U.S. patent application number 15/232872 was filed with the patent office on 2016-12-01 for pattern forming method, resist composition for multiple development used in the pattern forming method, developer for negative development used in the pattern forming method, and rinsing solution for negative development used in the pattern forming method.
This patent application is currently assigned to FUJIFILM Corporation. The applicant listed for this patent is FUJIFILM Corporation. Invention is credited to Shinichi KANNA, Hideaki TSUBAKI.
Application Number | 20160349619 15/232872 |
Document ID | / |
Family ID | 39106125 |
Filed Date | 2016-12-01 |
United States Patent
Application |
20160349619 |
Kind Code |
A1 |
TSUBAKI; Hideaki ; et
al. |
December 1, 2016 |
PATTERN FORMING METHOD, RESIST COMPOSITION FOR MULTIPLE DEVELOPMENT
USED IN THE PATTERN FORMING METHOD, DEVELOPER FOR NEGATIVE
DEVELOPMENT USED IN THE PATTERN FORMING METHOD, AND RINSING
SOLUTION FOR NEGATIVE DEVELOPMENT USED IN THE PATTERN FORMING
METHOD
Abstract
A pattern forming method, including: (A) coating a substrate
with a positive resist composition of which solubility in a
positive developer increases and solubility in a negative developer
decreases upon irradiation with actinic rays or radiation, so as to
form a resist film; (B) exposing the resist film; and (D)
developing the resist film with a negative developer; a positive
resist composition for multiple development used in the method; a
developer for use in the method; and a rinsing solution for
negative development used in the method.
Inventors: |
TSUBAKI; Hideaki; (Shizuoka,
JP) ; KANNA; Shinichi; (Shizuoka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIFILM Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
FUJIFILM Corporation
Tokyo
JP
|
Family ID: |
39106125 |
Appl. No.: |
15/232872 |
Filed: |
August 10, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14973097 |
Dec 17, 2015 |
9465298 |
|
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15232872 |
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|
14549164 |
Nov 20, 2014 |
9291904 |
|
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14973097 |
|
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|
13588762 |
Aug 17, 2012 |
8951718 |
|
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14549164 |
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13285782 |
Oct 31, 2011 |
|
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|
13588762 |
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11964454 |
Dec 26, 2007 |
8227183 |
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13285782 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/30 20130101; G03F
7/039 20130101; G03F 7/325 20130101; G03F 7/2024 20130101; G03F
7/32 20130101; G03F 7/16 20130101; G03F 7/0397 20130101; G03F 7/038
20130101; G03F 7/0392 20130101; G03F 7/2002 20130101; G03F 7/40
20130101; Y10T 428/24802 20150115 |
International
Class: |
G03F 7/32 20060101
G03F007/32; G03F 7/40 20060101 G03F007/40; G03F 7/038 20060101
G03F007/038; G03F 7/16 20060101 G03F007/16; G03F 7/20 20060101
G03F007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 25, 2006 |
JP |
2006-347560 |
Apr 11, 2007 |
JP |
2007-103901 |
Apr 26, 2007 |
JP |
2007-117158 |
Dec 18, 2007 |
JP |
2007-325915 |
Claims
1. A method of manufacturing an electronic device, comprising:
applying, to a substrate, a resist composition of which solubility
in a positive developer which is an alkali developer increases and
solubility in a negative developer containing an organic solvent
decreases upon irradiation with actinic rays or radiation, so as to
form a resist film; exposing the resist film; and developing the
resist film with the negative developer, wherein the negative
developer containing an organic solvent is a developer consisting
of butyl acetate, and the resist composition contains a resin
having a monocyclic or polycyclic alicyclic hydrocarbon structure
and contains a repeating unit represented by the following formula
(pA): ##STR00102## wherein R represents a hydrogen atom, a halogen
atom or a linear or branched alkyl group having a carbon number of
1 to 4, and a plurality of R's may be the same or different; A
represents a single bond, or a sole group or a combination of two
or more groups selected from the group consisting of an alkylene
group, an ether group, a thioether group, a carbonyl group, an
ester group, an amido group, a sulfonamido group, a urethane group
and a ureylene group; and Rp.sub.1 represents a group represented
by any one of the following formulae (pI) to (pV); ##STR00103## in
formulae (pI) to (pV), R.sub.11 represents a methyl group, an ethyl
group, an n-propyl group, an isopropyl group, an n-butyl group, an
isobutyl group or a sec-butyl group; Z represents an atomic group
necessary for forming a cycloalkyl group together with the carbon
atom; R.sub.12 to R.sub.16 each independently represents a linear
or branched alkyl group having a carbon number of 1 to 4 or a
cycloalkyl group, provided that at least one of R.sub.12 to
R.sub.14 or either one of R.sub.15 and R.sub.16 represents a
cycloalkyl group; R.sub.17 to R.sub.21 each independently
represents a hydrogen atom, a linear or branched alkyl group having
a carbon number of 1 to 4 or a cycloalkyl group, provided that at
least one of R.sub.17 to R.sub.21 represents a cycloalkyl group and
that either one of R.sub.19 and R.sub.21 represents a linear or
branched alkyl group having a carbon number of 1 to 4 or a
cycloalkyl group; R.sub.22 to R.sub.25 each independently
represents a hydrogen atom, a linear or branched alkyl group having
a carbon number of 1 to 4 or a cycloalkyl group, provided that at
least one of R.sub.22 to R.sub.25 represents a cycloalkyl group;
and R.sub.23 and R.sub.24 may combine with each other to form a
ring.
2. The method of manufacturing an electronic device according to
claim 1, wherein the resin has a lactone group.
3. The method of manufacturing an electronic device according to
claim 1, further comprising: washing the resist film with a rinsing
solution containing an organic solvent after the developing of the
resist film with the negative developer.
4. The method of manufacturing an electronic device according to
claim 3, wherein the rinsing solution contains at least one kind of
an organic solvent selected from the group consisting of a
hydrocarbon-based solvent, a ketone-based solvent, an ester-based
solvent, an alcohol-based solvent, an amide-based solvent and an
ether-based solvent.
5. The method of manufacturing an electronic device according to
claim 3, wherein the rinsing solution contains at least one kind of
an organic solvent selected from the group consisting of an
alcohol-based solvent and an ester-based solvent.
6. The method of manufacturing an electronic device according to
claim 1, wherein the resist composition further contains a basic
compound.
7. The method of manufacturing an electronic device according to
claim 1, wherein the resist composition further contains a
fluorine-containing surfactant, a silicon-containing surfactant or
a surfactant containing both a fluorine atom and a silicon
atom.
8. The method of manufacturing an electronic device according to
claim 1, wherein the exposing of the resist film is performed with
light having a wavelength of 193 nm.
9. A method of manufacturing an electronic device, comprising:
applying, to a substrate, a resist composition of which solubility
in a positive developer which is an alkali developer increases and
solubility in a negative developer containing an organic solvent
decreases upon irradiation with actinic rays or radiation, so as to
form a resist film; exposing the resist film; and developing the
resist film with the negative developer, wherein the resist
composition contains a resin having a monocyclic or polycyclic
alicyclic hydrocarbon structure and contains a repeating unit
represented by the following formula (pA): ##STR00104## wherein R
represents a hydrogen atom, a halogen atom or a linear or branched
alkyl group having a carbon number of 1 to 4, and a plurality of
R's may be the same or different; A represents a single bond, or a
sole group or a combination of two or more groups selected from the
group consisting of an alkylene group, an ether group, a thioether
group, a carbonyl group, an ester group, an amido group, a
sulfonamido group, a urethane group and a ureylene group; and
Rp.sub.1 represents a group represented by any one of the following
formulae (pI) to (pV); ##STR00105## in formulae (pI) to (pV),
R.sub.11 represents a methyl group, an ethyl group, an n-propyl
group, an isopropyl group, an n-butyl group, an isobutyl group or a
sec-butyl group; Z represents an atomic group necessary for forming
a cycloalkyl group together with the carbon atom; R.sub.12 to
R.sub.16 each independently represents a linear or branched alkyl
group having a carbon number of 1 to 4 or a cycloalkyl group,
provided that at least one of R.sub.12 to R.sub.14 or either one of
R.sub.15 and R.sub.16 represents a cycloalkyl group; R.sub.17 to
R.sub.21 each independently represents a hydrogen atom, a linear or
branched alkyl group having a carbon number of 1 to 4 or a
cycloalkyl group, provided that at least one of R.sub.17 to
R.sub.21 represents a cycloalkyl group and that either one of
R.sub.19 and R.sub.21 represents a linear or branched alkyl group
having a carbon number of 1 to 4 or a cycloalkyl group; R.sub.22 to
R.sub.25 each independently represents a hydrogen atom, a linear or
branched alkyl group having a carbon number of 1 to 4 or a
cycloalkyl group, provided that at least one of R.sub.22 to
R.sub.25 represents a cycloalkyl group; and R.sub.23 and R.sub.24
may combine with each other to form a ring; wherein the negative
developer containing an organic solvent is
ethyl-3-ethoxypropionate.
10. The method of manufacturing an electronic device according to
claim 9, wherein the resin has a lactone group.
11. The method of manufacturing an electronic device according to
claim 9, further comprising: washing the resist film with a rinsing
solution containing an organic solvent after the developing of the
resist film with the negative developer.
12. The method of manufacturing an electronic device according to
claim 11, wherein the rinsing solution contains at least one kind
of an organic solvent selected from the group consisting of a
hydrocarbon-based solvent, a ketone-based solvent, an ester-based
solvent, an alcohol-based solvent, an amide-based solvent and an
ether-based solvent.
13. The method of manufacturing an electronic device according to
claim 11, wherein the rinsing solution contains at least one kind
of an organic solvent selected from the group consisting of an
alcohol-based solvent and an ester-based solvent.
14. The method of manufacturing an electronic device according to
claim 9, wherein the resist composition further contains a basic
compound.
15. The method of manufacturing an electronic device according to
claim 9, wherein the resist composition further contains a
fluorine-containing surfactant, a silicon-containing surfactant or
a surfactant containing both a fluorine atom and a silicon
atom.
16. The method of manufacturing an electronic device according to
claim 9, wherein the exposing of the resist film is performed with
light having a wavelength of 193 nm.
Description
[0001] This is a continuation of U.S. application Ser. No.
14/973,097, filed Dec. 17, 2015, which is a continuation of U.S.
application Ser. No. 14/549,164, filed Nov. 20, 2014 (now U.S. Pat.
No. 9,291,094), which is a continuation of U.S. application Ser.
No. 13/588,762, filed Aug. 17, 2012 (now U.S. Pat. No. 8,951,718),
which is a continuation of U.S. application Ser. No. 13/285,782,
filed Oct. 31, 2011 (now abandoned), which is a continuation of
U.S. application Ser. No. 11/964,454, filed Dec. 26, 2007 (now U.S.
Pat. No. 8,227,183), which claims priority from JP 2006-347560,
filed Dec. 25, 2006, JP 2007-103901 filed Apr. 11, 2007, JP
2007-117158, filed Apr. 26, 2007 and JP 2007-325915, filed Dec. 18,
2007, the contents of all of which are hereby incorporated by
reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a pattern forming method
for use in the process of producing a semiconductor such as IC, in
the production of a circuit board for liquid crystal, thermal head
and the like, and in the lithography process of other photo
applications; a positive resist composition for multiple
development used in the pattern forming method; a developer for
negative development used in the pattern forming method; and a
rinsing solution for negative development used in the pattern
forming method. More specifically, the present invention relates to
a pattern forming method suitable for exposure with an ArF exposure
apparatus using a light source that emits far ultraviolet light at
a wavelength of 300 nm or less or with an immersion-type projection
exposure apparatus; a positive resist composition for multiple
development used in the pattern forming method; a developer for
negative development used in the pattern forming method; and a
rinsing solution for negative development used in the pattern
forming method.
[0004] 2. Description of the Related Art
[0005] Since the advent of a resist for KrF excimer laser (248 nm),
an image forming method called chemical amplification is used as a
resist image forming method so as to compensate for sensitivity
reduction incurred from light absorption. For example, the image
forming method by positive chemical amplification is an image
forming method of decomposing an acid generator in the exposed area
by exposure to generate an acid, converting an alkali-insoluble
group into an alkali-soluble group by using the generated acid as a
reaction catalyst in the post-exposure baking (PEB), and removing
the exposed area by alkali development.
[0006] Along with the finer fabrication of a semiconductor device,
there is becoming shorter the wavelength of the exposure light
source and higher the numerical aperture (high NA) of the
projection lens, and an exposure machine using an ArF excimer laser
having a wavelength of 193 nm as a light source has been so far
developed. As commonly well known, these features can be expressed
by the following formulae:
(Resolving power)=k.sub.1(.lamda./NA)
(Focal depth)=.+-.k.sub.2.lamda./NA.sup.2
wherein .lamda. is the wavelength of the exposure light source, NA
is the numerical aperture of the projection lens, and k.sub.1 and
k.sub.2 are coefficients related to the process.
[0007] A so-called immersion method of filling a high
refractive-index liquid (hereinafter sometimes referred to as an
"immersion liquid") between the projection lens and the sample has
been conventionally advocated as a technique of increasing the
resolving power.
[0008] As for the "effect of immersion", assuming that NA.sub.0=sin
.theta., the above-described resolving power and focal depth in the
immersion can be expressed by the following formulae:
(Resolving power)=k.sub.1(.lamda..sub.0/n)/NA.sub.0
(Focal depth)=.+-.k.sub.2(.lamda..sub.0/n)/NA.sub.0.sup.2
wherein .lamda..sub.0 is the wavelength of exposure light in air, n
is the refractive index of the immersion liquid based on air, and
.theta. is the convergence half-angle of beam.
[0009] That is, the effect of immersion is equal to use of an
exposure wavelength of 1/n. In other words, in the case of a
projection optical system with the same NA, the focal depth can be
made n times larger by the immersion. This is effective for all
pattern profiles and can be combined with a super-resolution
technique under study at present, such as phase-shift method and
modified illumination method.
[0010] A double exposure technology or a double patterning
technology is being advocated as a technique for more enhancing the
resolving power. This is to make small k.sub.1 in the
above-described formula of resolving power and is positioned as a
resolving power-increasing technique.
[0011] In conventional pattern formation of an electronic device
such as semiconductor device, a mask or reticle pattern in a size
of 4 to 5 times larger than the pattern intended to form is reduced
and transferred on an exposure target such as wafer by using a
reduction projection exposure apparatus.
[0012] With the progress to finer dimension, the conventional
exposure system comes to encounter a problem that lights irradiated
on adjacent patterns interfere each other to decrease the optical
contrast. Therefore, in these techniques, a process of dividing the
exposure mask design into two or more parts and synthesizing an
image by independently exposing these masks is being employed. In
these double exposure systems, it is necessary to divide the
exposure mask design and again synthesize an image of the design on
an exposure target (wafer), and division of the mask design needs
to be devised so that the pattern on the reticle can be faithfully
reproduced on the exposure target.
[0013] Studies of applying the effect of these double exposure
systems to the transfer of a fine image pattern of a semiconductor
device are introduced, for example, in JP-A-2006-156422 (the term
"JP-A" as used herein means an "unexamined published Japanese
patent application").
[0014] Also, the recent progress of double exposure technology is
reported in SPIE Proc 5754, 1508 (2005), SPIE Proc 5377, 1315
(2004), SPIE Proc 61531K-1 (2006) and the like.
[0015] However, in these double exposure systems, the pattern
formation needs to be performed in the vicinity of resolution limit
of the resist and therefore, if the pattern formation is performed
by merely applying the conventional resist composition to the
conventional resist process, there arises a problem that sufficient
exposure margin or focal depth cannot be obtained.
[0016] In other words, when the pattern forming process of coating
a positive resist composition on a substrate and subjecting the
resist film to exposure and development with an alkali developer
described, for example, in SP-A-2001-109154 or the pattern forming
process of coating a negative resist composition on a substrate and
subjecting the resist film to exposure and development with an
alkali developer described, for example, in JP-A-2003-76019 is
applied to a double exposure process, a sufficiently high resolving
performance cannot be obtained.
[0017] As regards the developer for g-line, I-line, KrF, ArF, EB or
EUV lithography, an aqueous alkali developer of 2.38 mass % TMAH
(tetramethylammonium hydroxide) is being used at present as a
positive resist developer and a negative resist developer.
[0018] Other than the above-described developer, for example,
JP-A-2001-215731 describes a positive resist developer containing
an aliphatic linear ether-based solvent or aromatic ether-based
solvent and a ketone-based solvent having a carbon number of 5 or
more, which is used for developing a resist material containing a
copolymer of a styrene-based monomer and an acryl-based monomer.
Also, JP-A-2006-227174 describes a positive resist developer having
at least two or more acetic acid groups, ketone groups, ether
groups or phenyl groups and having a molecular weight of 150 or
more, which is used for a resist material capable of dissolving in
a solvent as a result of reduction in the molecular weight due to
breakage of the polymer chain upon irradiation with radiation.
JP-A-6-194847 describes a negative photoresist developer, where an
aromatic compound having a carbon number of 6 to 12 or a mixed
solvent containing 50 mass % or more of an aromatic compound having
a carbon number of 6 to 12 is used as the developer for developing
a negative photoresist mainly comprising a photosensitive
polyhydroxy ether resin obtained by the reaction of a polyhydroxy
ether resin and a diglycidyl(meth)acrylate.
[0019] Furthermore, JP-T-2002-525683 (the term "JP-T" as used
herein means a "published Japanese translation of a PCT patent
application") describes a positive resist developer for developing
a resist composition containing a specific fluorine-containing
resin, where the positive resist developer contains an organic
solvent, particularly, a halogenated organic solvent, and
JP-T-2006-518779 describes a negative resist developer for
developing a negative photoresist composition containing a specific
polycyclic olefin polymer, where the negative resist developer
contains one or more solvents selected from the group consisting of
propylene glycol methyl ether acetate, cyclohexanone, butyrolactate
and ethyl lactate.
[0020] JP-A-2000-199953 discloses a method to improve the
resolution double with an ordinary positive resist.
[0021] However, the above-described combinations of a resist
compositions and a developer merely provide a system of performing
pattern formation by combining a specific resist composition with
either a positive developer or a negative developer.
[0022] That is, as shown in FIG. 1, in the case of a positive
system (a combination of a resist composition and a positive
developer), a material system of performing pattern formation by
selectively dissolving and removing the region having a strong
light irradiation intensity out of the optical aerial image (light
intensity distribution) is merely provided. On the other hand, as
for the combination of a negative system (a resist composition and
a negative developer), a material system of performing pattern
formation by selectively dissolving and removing the region having
a weak light irradiation intensity is merely provided.
SUMMARY OF THE INVENTION
[0023] An object of the present invention is to solve those
problems and provide a method for stably forming a high-precision
fine pattern to produce a highly integrated electronic device with
high precision.
[0024] The present invention has the following constructions, and
the object of the present invention has been attained by these
constructions. [0025] (1) A pattern forming method, comprising;
[0026] (A) coating a substrate with a positive resist composition
of which solubility in a positive developer increases and
solubility in a negative developer decreases upon irradiation with
actinic rays or radiation, so as to form a resist film; [0027] (B)
exposing the resist film; and [0028] (D) developing the resist film
with a negative developer. [0029] (2) The pattern forming method as
described in (I) above, which further comprises: [0030] (C)
developing the resist film with a positive developer, [0031] (3) A
pattern forming method, comprising in the following order: [0032]
(A) coating a substrate with a positive resist composition of which
solubility in a positive developer increases and solubility in a
negative developer decreases upon irradiation with actinic rays or
radiation, so as to form a resist film; [0033] (B) exposing the
resist film; [0034] (D) developing the resist film with a negative
developer; and [0035] (C) developing the resist film with a
positive developer. [0036] (4) The pattern forming method as
described in any of (1) to (3) above, which further comprises:
[0037] (E) heating (baking, also called PEB (post exposure bake))
resist film after (B) exposing the resist film. [0038] (5) The
pattern forming method as described in any of (1) to (4) above,
comprising: [0039] (B) exposing the resist film a plurality of
times. [0040] (6) The pattern forming method as described in (4) or
(5) above, comprising: [0041] (E) heating (baking, also called PEB
(post exposure bake)) the resist film a plurality of times. [0042]
(7) A pattern forming method, comprising in the following order:
[0043] (A) coating a substrate with a positive resist composition
for multiple development of which solubility in a positive
developer increases and solubility in a negative developer
decreases upon irradiation with actinic rays or radiation, so as to
form a resist film; [0044] (B-1) exposing the resist film; [0045]
(E-1) heating (baking, also called PEB (post exposure bake)) the
resist film; [0046] (C) developing the resist film with a positive
developer, so as to form a patterned resist film; [0047] (B-2)
exposing the patterned resist film; [0048] (E-2) heating (baking,
also called PEB (post exposure bake)) the patterned resist film;
and [0049] (D) developing the patterned resist film with a negative
developer. [0050] (8) A pattern forming method, comprising in the
following order: [0051] (A) coating a substrate with a positive
resist composition for multiple development of which solubility in
a positive developer increases and solubility in a negative
developer decreases upon irradiation with actinic rays or
radiation, so as to form a resist film; [0052] (B-1) exposing the
resist film; [0053] (E-1) heating (baking, also called PEB (post
exposure bake)) the resist film; [0054] (D) developing the resist
film with a negative developer, so as to form a patterned resist
film; [0055] (B-2) exposing the patterned resist film; [0056] (E-2)
heating (baking, also called PEB (post exposure bake)) the
patterned resist film; and [0057] (C) developing the patterned
resist film with a positive developer. [0058] (9) The pattern
forming method as described in (7) or (8) above, [0059] wherein the
positive resist composition for multiple development comprises a
resin having an alicyclic hydrocarbon structure and being capable
of increasing solubility in an alkali developer and decreasing
solubility in an organic solvent under an action of an acid. [0060]
(10) The pattern forming method as described in any of (1) to (9)
above, [0061] wherein (D) developing the resist film with a
negative developer is performing development with a developer
containing at least one kind of a solvent selected from the group
consisting of a ketone-based solvent, an ester-based solvent, an
alcohol-based solvent, an amide-based solvent and an ether-based
solvent. [0062] (11) The pattern forming method as described in any
of (1) to (10) above, [0063] wherein (D) developing the resist film
with a negative developer is performing development with a
developer containing a solvent represented by formula (1):
[0063] ##STR00001## [0064] wherein R and R' each independently
represents a hydrogen, atom, an alkyl group, a cycloalkyl group, an
alkoxyl group, an alkoxycarbonyl group, a carboxyl group, a
hydroxyl group, a cyano group or a halogen atom, and R and R' may
combine with each other to form a ring. [0065] (12) The pattern
forming method as described in any of (1) to (11) above, [0066]
wherein (D) developing the resist film with a negative developer is
performing development with a developer containing a solvent
represented by formula (2):
[0066] ##STR00002## [0067] wherein R'' and R''' each independently
represents a hydrogen atom, an alkyl group, a cycloalkyl group, an
alkoxyl group, an alkoxycarbonyl group, a carboxyl group, a
hydroxyl group, a cyano group or a halogen atom, and R'' and R''''
may combine with each other to form a ring; and [0068] R'''
represents an alkylene group or a cycloalkylene group. [0069] (13)
The pattern forming method as described in any of (1) to (11)
above, [0070] wherein (D) developing the resist film with a
negative developer is performing development with a developer
containing butyl acetate. [0071] (14) The pattern forming method as
described in any of (2) to (13) above, [0072] wherein (C)
developing the resist film with a positive developer is selectively
dissolving and removing a film, an exposure dose of which is not
less than a threshold value (a), and [0073] (D) developing the
resist film with a negative developer is selectively dissolving and
removing a film, an exposure dose of which is not more than a
threshold value (b). [0074] (15) The pattern forming method as
described in any of (1) to (14) above, which further comprises:
[0075] (F) washing the resist film with a rinsing solution
containing an organic solvent after (D) developing the resist film
with a negative developer. [0076] (16) A positive resist
composition for multiple development, comprising: [0077] (a) a
resin capable of increasing solubility in an alkali developer and
decreasing solubility in an organic solvent by decomposition of a
side chain; [0078] (b) a photoacid generator; and [0079] (c) a
solvent. [0080] (17) A developer for negative development, which is
used for a positive resist composition, the developer comprising:
[0081] at least one kind of a solvent selected from the group
consisting of a ketone-based solvent, an ester-based solvent, an
alcohol-based solvent, an amide-based solvent and an ether-based
solvent. [0082] (18) A rinsing solution for negative development,
which is used for a positive resist composition, the rinsing
solution comprising: [0083] at least one kind of an organic solvent
selected from the group consisting of a hydrocarbon-based solvent,
a ketone-based solvent, an ester-based solvent, an alcohol-based
solvent, an amide-based solvent and an ether-based solvent.
[0084] Preferred embodiments of the present invention are further
set forth below. [0085] (19) The pattern forming method as
described in (14) above, [0086] wherein the threshold value
(a)>the threshold value (b). [0087] (20) The pattern forming
method as described in (7) or (8) above, [0088] wherein an exposure
dose (Eo1 [mJ/cm.sup.2]) in (B-1) exposing the resist film and an
exposure dose (Eo2 [mJ/cm.sup.2]) in (B-2) exposing the patterned
resist film satisfy the following formula:
[0088] Eo1<Eo2-5 [0089] (21) The pattern forming method as
described in (15) above, [0090] wherein the rinsing solution
contains at least one kind of an organic solvent selected from the
group consisting of a hydrocarbon-based solvent, a ketone-based
solvent, an ester-based solvent, an alcohol-based solvent, an
amide-based solvent and an ether-based solvent, [0091] (22) The
pattern forming method as described in any of (1) to (15) and (19)
to (21) above, [0092] wherein the positive resist composition
comprises: [0093] (A) a resin of which solubility in an alkali
developer increases under an action of an acid; [0094] (B) a
compound capable of generating an acid upon irradiation with
actinic rays or radiation; and [0095] (C) a solvent. [0096] (23)
The pattern forming method as described in (22) above, [0097]
wherein the resin of the component (A) of the positive resist
composition has an alicyclic hydrocarbon structure. [0098] (24) The
pattern forming method as described in (22) or (23) above, [0099]
wherein the resin of the component (A) of the positive composition
has a weight average molecular weight of 1,000 to 100,000. [0100]
(25) The pattern forming method as described in any of (22) to (24)
above, [0101] wherein the resin of the component (A) of the
positive resist composition is a (meth)acrylic resin having a
lactone structure. [0102] (26) The pattern forming method as
described in any of (22) to (25) above, [0103] wherein the positive
resist composition further comprises a basic compound. [0104] (27)
The pattern forming method as described, in any of (22) to (26)
above, [0105] wherein the positive resist composition further
comprises at least one of a fluorine-containing surfactant and a
silicon-containing surfactant, [0106] (28) The pattern forming
method as described in any of (22) to (27) above, [0107] wherein
the positive resist composition further comprises a resin having at
least one of a fluorine atom and a silicon atom. [0108] (29) The
pattern forming method as described in (15) or (21) above, [0109]
wherein the rinsing solution containing an organic solvent contains
at least one kind of an organic solvent selected from the group
consisting of a hydrocarbon-based solvent, a ketone-based solvent,
an ester-based solvent, an alcohol-based solvent and an amide-based
solvent. [0110] (30) The pattern forming method as described in
(15), (21) or (29) above, [0111] wherein the rinsing solution
containing an organic solvent contains at least one kind of an
organic solvent selected from the group consisting of an
alcohol-based solvent and an ester-based solvent. [0112] (31) The
pattern forming method as described in any of (15), (29) and (30)
above, [0113] wherein the rinsing solution containing an organic
solvent contains a monohydric alcohol having a carbon number of 1
to 8. [0114] (32) A pattern forming method, comprising in the
following order: [0115] (A) coating a substrate with a positive
resist composition for multiple development of which solubility in
a positive developer increases and solubility in a negative
developer decreases upon irradiation with actinic rays or
radiation, so as to form a resist film; [0116] (B-1) exposing the
resist film; [0117] (E-1) heating (baking, also called PEB (post
exposure bake)) the resist film; [0118] (C) developing the resist
film with a positive developer, so as to form a patterned resist
film; [0119] (B-2) exposing the patterned resist film; [0120] (E-2)
heating (baking, also called PEB (post exposure bake)) the
patterned resist film; [0121] (D) developing the patterned resist
with a negative developer; and [0122] (F) washing the patterned
resist film with a rinsing solution containing an organic solvent.
[0123] (33) A pattern forming method, comprising in the following
order: [0124] (A) coating a substrate with a positive resist
composition for multiple development of which solubility in a
positive developer increases and solubility in a negative developer
decreases upon irradiation with actinic rays or radiation, so as to
form a resist film; [0125] (B-1) exposing the resist film; [0126]
(E-1) heating (baking, also called PEB (post exposure bake)) the
resist film; [0127] (D) developing the resist film with a negative
developer; [0128] (F) washing the resist film with a rinsing
solution containing an organic solvent, so as to form a patterned
resist film; [0129] (B-2) exposing the patterned resist film;
[0130] (E-2) heating (baking, also called PEB (post exposure bake))
the patterned resist film; and [0131] (C) developing the patterned
resist film with a positive developer. [0132] (34) The pattern
forming method as described in any of (1) to (15) and (19) to (33)
above, [0133] wherein the exposure is performed using a wavelength
of 200 nm or less. [0134] (35) The pattern forming method as
described in any of (1) to (15) and (19) to (34) above, [0135]
wherein the exposure is performed at a wavelength of 193 nm. [0136]
(36) The pattern forming method as described in any of (1) to (15)
and (19) to (35) above, [0137] wherein immersion exposure is
performed at a wavelength of 193 nm. [0138] (37) The pattern
forming method as described in any of (2) to (15) and (19) to (36)
above, [0139] wherein developing the resist film with a positive
developer is performing development with an alkali developer.
[0140] (38) The pattern forming method as described in (7) or (8)
above, [0141] wherein a temperature in (E-1) heating (baking, also
called PEB (post exposure bake)) the resist film is higher than a
temperature in (E-2) heating (baking, also called PEB (post
exposure bake)) the patterned resist film. [0142] (39) The positive
resist composition as described in (16) above, [0143] wherein the
resin, of the component (a) is a resin having an alicyclic
hydrocarbon structure. [0144] (40) The positive resist composition
as described in (16) or (39) above, [0145] wherein the resin of the
component (a) is at least one of an acrylic resin and a methacrylic
resin each having an alicyclic hydrocarbon structure. [0146] (41)
The positive resist composition for multiple development as
described in any of (16), (39) and (40) above, [0147] wherein the
resin of the component (a) has a weight average molecular weight of
from 1,000 to 100,000. [0148] (42) The positive resist composition
for multiple development as described in any of (16) and (39) to
(41) above, [0149] wherein the resin of the component (a) is a
(meth)acrylic resin having a lactone structure. [0150] (43) The
positive resist composition for multiple development as described
in any of (16) and (39) to (42) above, which further comprises a
basic compound. [0151] (44) The positive resist composition for
multiple development as described in any of (16) and (39) to (43)
above, which further comprises at least one of a
fluorine-containing surfactant and a silicon-containing surfactant.
[0152] (45) The positive resist composition for multiple
development as described in any of (16) and (39) to (44) above,
which farther comprises a resin having at least one of a fluorine
atom and a silicon atom. [0153] (46) The developer as described in
(17) above, which comprises a solvent represented by formula
(1):
[0153] ##STR00003## [0154] wherein R and R' each independently
represents a hydrogen atom, an alkyl group, a cycloalkyl group, an
alkoxyl group, an alkoxycarbonyl group, a carboxyl group, a
hydroxyl group, a cyano group or a halogen atom, and R and R' may
combine with each other to form a ring. [0155] (47) The developer
as described in (17) or (46) above, which comprises a solvent
represented by formula (2):
[0155] ##STR00004## [0156] wherein R'' and R'''' each independently
represents a hydrogen atom, an alkyl group, a cycloalkyl group, an
alkoxyl group, an alkoxycarbonyl group, a carboxyl group, a
hydroxyl group, a cyano group or a halogen atom, and R'' and R''''
may combine with each other to form a ring; and [0157] R'''
represents an alkylene group or a cycloalkylene group. [0158] (48)
The developer as described in (17) or (46) above, which comprises
butyl acetate. [0159] (49) The developer for negative development
as described in any of (17) and (46) to (48) above, which comprises
two or more kinds of solvents. [0160] (50) The rinsing solution as
described in (18) above, which comprises at least one kind of an
organic solvent selected from the group consisting of a
hydrocarbon-based solvent, a ketone-based solvent, an ester-based
solvent, an alcohol-based solvent and an amide-based solvent.
[0161] (51) The rinsing solution as described in (17) (50) above,
which comprises an alcohol-based solvent or an ester-based solvent.
[0162] (52) The rinsing solution as described in any of (17), (50)
and (51) above, which comprises a monohydric alcohol having a
carbon number of 6 to 8. [0163] (53) The rinsing solution for
negative development as described in any of (17) and (50) to (52)
above, which comprises two or more kinds of solvents. [0164] (54)
The rinsing solution for negative development as described in any
of (17) and (50) to (53) above, which comprises at least one
developer component used in performing negative development.
BRIEF DESCRIPTION OF THE DRAWINGS
[0165] FIG. 1 represents a schematic view showing the relationship
among positive development, negative development and exposure dose
in a conventional method;
[0166] FIG. 2 represents a schematic view showing the relationship
among positive development, negative development and exposure dose
in the method of the present invention;
[0167] FIG. 3 represents a graph showing the relationship between
exposure dose and residual film curve when a positive developer or
a negative developer is used;
[0168] FIG. 4 represents a schematic view showing the relationship
among positive development, negative development and exposure dose
in the method of the present invention;
[0169] FIG. 5 represents a schematic view showing the relationship
among positive development, negative development and exposure dose
in the method of the present invention;
[0170] FIG. 6 represents a schematic view showing the relationship
among positive development, negative development and exposure dose
in the method of the present invention;
[0171] FIG. 7 represents a view showing the spatial intensity
distribution of an optical image;
[0172] FIG. 8 represents a schematic view showing the relationship
among positive development, threshold value (a) and light
intensity;
[0173] FIG. 9 represents a schematic view showing the spatial
intensity distribution of an optical image;
[0174] FIG. 10 represents a schematic view showing the relationship
among negative development, threshold value (b) and light
intensity; and
[0175] FIG. 11 represents a schematic view showing the state of
forming a pattern by two exposure processes.
DETAILED DESCRIPTION OF THE INVENTION
[0176] The best mode for carrying out the present invention is
described below.
[0177] Incidentally, in the present invention, when a group (atomic
group) is denoted without specifying whether substituted or
unsubstituted, the group includes both a group having no
substituent and a group having a substituent. For example, an
"alkyl group" includes not only an alkyl group having no
substituent (unsubstituted alkyl group) but also an alkyl group
having a substituent (substituted alkyl group).
[0178] The present invention provides, as a technique for enhancing
the resolving power, a new pattern forming method using a
combination of a developer (negative developer) capable of
selectively dissolving and removing an exposed area not more than a
predetermined threshold value (b), and a positive resist
composition capable of forming a film of which solubility in a
negative developer (preferably an organic developer) decreases upon
irradiation with actinic ray or radiation.
[0179] The present invention provides, as a technique for enhancing
the resolving power, a new pattern forming method using preferably
a combination of a developer (positive developer) capable of
selectively dissolving and removing an exposed area not less than
predetermined threshold value (a), a developer (negative developer)
capable of selectively dissolving and removing an exposed area not
more than a predetermined threshold value (b), and a positive
resist composition capable of forming a film of which solubility in
a positive developer (preferably an alkali developer) increases and
solubility in a negative developer (preferably an organic
developer) decreases upon irradiation with actinic ray or
radiation.
[0180] That is, as shown in FIG. 2, when a pattern element on an
exposure mask is projected on a wafer by light irradiation, the
region having a strong light irradiation intensity (exposed area
not less than a predetermined threshold value (a)) is dissolved and
removed using a positive developer and the region having a weak
light irradiation intensity (exposed area not more than a
predetermined threshold value (b)) is dissolved and removed using a
negative developer, whereby a pattern with resolution as high as 2
times the frequency of the optical aerial image (light intensity
distribution) can be obtained. Also, in the method of the present
invention, the design of the exposure mask need not be divided.
[0181] The pattern forming process necessary for practicing the
present invention comprises the following steps: [0182] (A) a step
of coating a substrate with a positive resist composition of which
solubility in a positive developer increases and solubility in a
negative developer decreases upon irradiation with actinic rays or
radiation, [0183] (B) an exposure step, and [0184] (D) a step of
developing the resist film with a negative developer.
[0185] The pattern forming method of the present invention
preferably further comprises (C) a step of developing the resist
film with a positive developer.
[0186] The pattern forming method of the present invention
preferably further comprises (F) a step of washing the resist film
with a rinsing solution containing an organic solvent, after the
step (D) of developing the resist film with a negative
developer.
[0187] The pattern forming method of the present invention
preferably comprises (E) a heating (baking, also called PEB (post
exposure bake)) step, after the exposure step (B).
[0188] In the pattern forming method of the present invention, the
exposure step (B) may be performed a plurality of times.
[0189] In the pattern forming method of the present invention, the
heating (baking, also called PEB (post exposure bake)) step (E) may
be performed a plurality of times.
[0190] In practicing the present invention, (a) a positive resist
composition of which solubility in a positive developer increases
and solubility in a negative developer decreases upon irradiation
with actinic rays or radiation, and (b) a negative developer
(preferably an organic developer) are necessary.
[0191] In practicing the present invention, (c) a positive
developer (preferably an alkali developer) is preferably further
used.
[0192] In practicing the present invention, (d) a rinsing solution
containing an organic solvent is preferably further used.
[0193] The pattern forming system includes a positive type and a
negative type and although both types utilize a phenomenon that the
solubility of the resist film in a developer is varied through a
chemical reaction triggered, by light irradiation, a resist causing
the light-irradiated part to dissolve in a developer is called a
positive system, and a resist causing the non-light-irradiated part
to dissolve in a developer is called a negative system. The
positive resist utilizes a chemical reaction such as polarity
conversion for enhancing the solubility in a developer, and the
negative resist utilizes bond formation between molecules, such as
crosslinking reaction or polymerization reaction.
[0194] Since the advent of a resist for KrF excimer lasers (248
nm), an image forming method called chemical amplification is used
as an image forming method for a resist so as to compensate for
sensitivity reduction caused by light absorption. The image forming
method, for example, using positive chemical amplification is an
image forming method where an acid generator in the exposed area
decomposes upon exposure to generate an acid, the acid generated is
used as a reaction catalyst in the baking after exposure (FEB: post
exposure bake) to convert the alkali-insoluble group into an
alkali-soluble group, and the exposed area is removed by alkali
development.
[0195] In the present invention, one positive resist composition
(a) acts as a positive resist for a positive developer and as a
negative resist for a negative developer.
[0196] In the present invention, an alkali developer (aqueous) can
be used as the positive developer, and an organic developer
containing an organic solvent can be used as the negative
developer.
[0197] Also, the positive resist composition (a) is a "resin
composition capable of thrilling a film of which solubility in an
alkali developer increases and solubility in an organic
solvent-containing developer decreases as a result of a chemical
reaction triggered by exposure to irradiation".
[0198] In conventionally employed negative image-forming systems
(negative resist+negative developer), a material system utilizing a
mechanism of increasing the molecular weight exclusively by the
bonding between molecules and decreasing the solubility in a
developer has been proposed. However, it has been difficult for the
image forming mechanism utilizing a change in the molecular weight
to establish a system such that one resist material system acts as
a positive resist for one developer and as a negative resist for
another developer.
[0199] In the present invention, the positive resist composition
(a) not only decreases in the solubility in a negative developer as
a result of a polarity conversion reaction of the polymer side
chain but also brings about both increase in the solubility in an
alkali developer and decrease in the solubility in an organic
developer particularly by virtue of a specific chemical reaction (a
polarity conversion reaction of the polymer side chain).
[0200] In the present invention, by the combination of a positive
resist composition and a negative developer or the combination of a
positive resist composition, a negative developer and a positive
developer, a fine pattern can be formed without generating a resist
residue.
[0201] In another preferred embodiment of the present invention,
first development using a negative developer (preferably an organic
developer) is performed, and second development using a positive
developer (preferably an alkali developer) is then performed,
whereby chipping of the resist pattern can be more suppressed. When
chipping of the resist pattern is suppressed, failure of the
circuit pattern transferred on a substrate can be reduced.
[0202] As disclosed, for example, in Macromolecules, Vol. 38,
1882-1898 (2005) and J. Photopolymer Science and Technology, Vol.
12, 545-551 (1999), it is important for obtaining a pattern with
good resolution performance to cause smooth penetration of the
developer into the resist film in the development step. The reason
why chipping of the resist pattern can be suppressed by performing,
in the development step, first development using a negative
developer and then performing second development using a positive
developer is not clearly known, but the combination of the positive
resist composition, the positive developer and the negative
developer of the present invention is considered to play an
important role. More specifically, it is considered that when
development is performed twice by using a negative developer and a
positive developer and these two development processes are
performed in the above-described order, the developer (positive
developer) in the second development step more smoothly penetrates
into the resist film, as a result, the uniformity of development is
enhanced and a pattern can be formed without causing chipping of
the resist pattern.
[0203] In the present invention, the matter of importance is to
control the "threshold value" of exposure dose (in the light
irradiation region, the exposure dose with which the film is
solubilized or insolubilized in the developer). The "threshold
value" is the minimum exposure dose to make the film soluble in a
positive developer and the minimum exposure dose to make the film
insoluble in a negative developer at the pattern formation for
obtaining a desired line width.
[0204] The "threshold value" can be determined as follows.
[0205] That is, the "threshold value" is the minimum exposure dose
to make the film soluble in a positive developer and the minimum
exposure dose to make the film insoluble in a negative developer at
the pattern formation for obtaining a desired line width.
[0206] The residual film ratio of the resist film to the exposure
dose is measured and at this time, as shown in FIG. 3, the exposure
dose giving a residual film ratio of 0% for the negative developer
is designated as a threshold value (a) and the exposure dose giving
a residual film ratio of 100% for the negative developer is
designated as a threshold value (b).
[0207] For example, as shown in FIG. 4, the threshold value (a) of
the minimum exposure dose to make the film soluble in the positive
developer is set to be higher than the threshold value (b) of the
minimum exposure dose to make the film insoluble in a negative
developer, whereby the pattern formation can be achieved by one
exposure process.
[0208] The method for controlling the threshold value includes a
method of controlling the material-related parameters of the
positive resist composition (a) and the developer or controlling
the parameters related to the process.
[0209] As for the material-related parameter, control of various
physical values related to solubility of the positive resist
composition (a) in the developer and the organic solvent, such as
SP value (solubility parameter) and Log value, is effective.
Specific examples thereof for the positive resist composition (a)
include the average molecular weight of polymer contained, the
molecular weight dispersity, the monomer compositional ratio, the
polarity of monomer, the monomer sequence, the polymer blend and
the addition of low molecular additive, and specific examples for
the developer include the concentration of developer, the addition
of low molecular additive and the addition of surfactant.
[0210] Also, specific examples of the process-related parameter
include the ation temperature, the film formation time, the
temperature and time of post-heating after exposure, the
temperature at development, the development time, the nozzle system
(puddle method) of developing apparatus, and the rinsing method
after development.
[0211] In the pattern forming process using two kinds of
developers, that is, a positive developer and a negative developer,
one exposure process may be performed as described above or two or
more exposure processes may be performed in the following manner.
That is, development using a positive developer or a negative
developer is performed after first exposure, and negative or
positive development using a developer different from that in the
first development is performed after second exposure.
[0212] A pattern forming method comprising, in order: [0213] (A) a
step of coating a substrate with a positive resist composition for
multiple development, of which solubility in a positive developer
increases and solubility in a negative developer decreases upon
irradiation with actinic rays or radiation, [0214] (B-1) a first
exposure step, [0215] (E-1) a first heating (baking, also called
PEB (post exposure bake)) step, [0216] (C) a step of developing the
resist film with a positive developer, [0217] (B-2) a second
exposure step, [0218] (E-2) a second heating (baking, also called
PEB (post exposure bake)) step, and [0219] (D) a step of developing
the resist film with a negative developer.
[0220] A pattern forming method shown in FIG. 6, comprising, in
order: [0221] (A) a step of coating a substrate with a positive
resist composition for multiple development, of which solubility in
a positive developer increases and solubility in a negative
developer decreases upon irradiation with actinic rays or
radiation, [0222] (B-1) a first exposure step, [0223] (E-1) a first
heating (baking, also called PEB (post exposure bake)) step, [0224]
(D) a step of developing the resist film with a negative developer,
[0225] (B-2) a second exposure step, [0226] (E-2) a second heating
(baking, also called PEB (post exposure bake)) step, and [0227] (C)
a step of developing the resist film with a positive developer.
[0228] As regards the positive resist composition for multiple
development, the positive resist composition described later can be
used.
[0229] When exposure is performed twice or more, this is
advantageous in that the latitude in the control of the threshold
value in the development, after first exposure and the control of
the threshold value in the development after second exposure
increases. In the case of performing the exposure twice or more,
the second exposure dose is preferably set to be larger than the
first exposure dose. Because, in the second development, the
threshold value is determined based on the amount to which the
history of first and second exposure doses is added, and when the
second exposure dose is sufficiently larger than the first exposure
dose, the first exposure dose is reduced in its effect and
depending on the case, can be neglected.
[0230] The exposure dose (Eo1 [mJ/cm.sup.2]) in the step of
performing first exposure is preferably 5 [mJ/cm.sup.2] or more
smaller than the exposure dose (Eo2 [mJ/cm.sup.2]) in the step of
performing second exposure. In this case, the history of first
exposure can be made to less affect the process of performing the
pattern formation by second exposure.
[0231] In the case of performing the exposure twice, the first
development is not limited to positive development, and development
using a negative developer may be performed first.
[0232] For changing the first exposure dose and the second exposure
dose, a method of adjusting the above-described various parameters
related to the material and process is effective. In particular,
control of the temperature in the first heating (baking, also
called PEB (post exposure bake)) step and the temperature in the
second heating (baking, also called PEB (post exposure bake)) step
is effective. That is, in order to make the first exposure dose to
be smaller than the second exposure dose, it is effective to set
the temperature in the first heating step to be higher than the
temperature in the second heating step.
[0233] The threshold value (a) in the positive development is as
follows in the actual lithography process.
[0234] A film comprising a positive resist composition of which
solubility in a positive developer increases and solubility in a
negative developer decreases upon irradiation with actinic rays or
radiation is formed on a substrate, and the resist film is exposed
through a photomask in a desired pattern size under desired
illumination conditions. At this time, the exposure is performed by
fluctuating the exposure focus in 0.05 [.mu.m] steps and the
exposure dose in 0.5 [mJ/cm.sup.2] steps. After the exposure, the
resist film is heated (baking, also called PEB (post exposure
bake)) at a desired temperature for a desired time and then
developed with an alkali developer in a desired concentration for a
desired time. After the development, the line width of the pattern
is measured using CD-SEM, and the exposure dose A [mJ/cm.sup.2] and
focus position for forming a desired line width are determined.
Subsequently, the intensity distribution of an optical image when
the above-described photomask is irradiated with a specific
exposure dose A [mJ/cm.sup.2] and a specific focus position is
calculated. The calculation can be performed using a simulation
software (Prolith, ver. 9.2.0.15, produced by KLA). Details of the
calculation method are described in Chris. A. Mack, Inside PROLITH,
Chapter 2, "Aerial Image Formation", FINLE Technologies, Inc.
[0235] As a result of calculation, for example, the spatial
intensity distribution shown in FIG. 7 of an optical image is
obtained.
[0236] Here, as shown in FIG. 8, the light intensity at a position
when the spatial position is shifted by 1/2 of the obtained pattern
line width from the minimum value in the spatial intensity
distribution of an optical image corresponds to the threshold value
(a).
[0237] The threshold value (b) in the negative development is as
follows in the actual lithography process.
[0238] A film comprising a positive resist composition of which
solubility in a positive developer increases and solubility in a
negative developer decreases upon irradiation with actinic rays or
radiation is formed on a substrate, and the resist film is exposed
through a photomask in a desired pattern size under desired
illumination conditions. At this time, the exposure is performed by
fluctuating the exposure focus in 0.05 [mJ/cm] steps and the
exposure dose in 0.5 [mJ/cm.sup.2] steps. After the exposure, the
resist film is heated (baking, also called PEB (post exposure
bake)) at a desired temperature for a desired time and then
developed with an organic developer in a desired concentration for
a desired time. After the development, the line width of the
pattern is measured using CD-SEM, and the exposure dose A
[mJ/cm.sup.2] and focus position for forming a desired line width
are determined. Subsequently, the intensity distribution of an
optical image when the above-described photomask is irradiated with
a specific exposure dose A [mJ/cm.sup.2] and a specific focus
position is calculated. The calculation is performed using a
simulation software (Prolith, produced by KLA).
[0239] For example, a spatial intensity distribution shown in FIG.
9 of an optical image is obtained.
[0240] Here, as shown in FIG. 10, the light intensity at a position
when the spatial position is shifted by 1/2 of the obtained pattern
line width from the maximum value in the spatial intensity
distribution of an optical image is defined as the threshold value
(b).
[0241] The threshold value (a) is preferably from 0.1 to 100
[mJ/cm.sup.2], more preferably from 0.5 to 50 [mJ/cm.sup.2], still
more preferably from 1 to 30 [mJ/cm.sup.2]. The threshold value (b)
is preferably from 0.1 to 100 [mJ/cm.sup.2], more preferably from
0.5 to 50 [mJ/cm.sup.2], still more preferably from 1 to 30
[mJ/cm.sup.2]. The difference between threshold values (a) and (b)
is preferably from 0.1 to 80 [mJ/cm.sup.2], more preferably from
0.5 to 50 [mJ/cm.sup.2], still more preferably from 1 to 30
[mJ/cm.sup.2].
[0242] In the present invention, the film formed on a substrate is
a film comprising a positive resist composition of which solubility
in a positive developer increases and solubility in a negative
developer decreases upon irradiation with actinic rays or
radiation.
[0243] The positive resist composition which can be used in the
present invention is described below.
(A) Resin of which Solubility in an Alkali Developer Increases and
Solubility in an Organic Solvent Decreases Under the Action of an
Acid
[0244] The resin of which solubility in an alkali developer
increases and solubility in an organic solvent decreases under the
action of an acid is a resin having a group capable of decomposing
under the action of an acid to produce an alkali-soluble group
(hereinafter sometimes referred to as an "acid-decomposable group")
on either one or both of the main chain and the side chain of the
resin (sometimes referred to as an "acid-decomposable resin", an
"acid-decomposable resin (A)" or a "resin (A)) and is preferably a
resin having a monocyclic or polycyclic alicyclic hydrocarbon
structure and being capable of increasing the solubility in an
alkali developer and decreasing the solubility in an organic
solvent under the action of an acid, because the polarity of the
resin is greatly changed between before and after irradiation of
actinic rays or radiation and when the resist film is developed
using a positive developer (preferably an alkali developer) and a
negative developer (preferably an organic solvent), the dissolution
contrast is enhanced. Furthermore, the resin having a monocyclic or
polycyclic alicyclic hydrocarbon structure generally has high
hydrophobicity and favors a high development rate at the time of
developing the resist film in a region of weak light irradiation
intensity with a negative developer (preferably an organic
developer), and the developability on use of a negative developer
is enhanced.
[0245] Examples of the alkali-soluble group include groups having a
phenolic hydroxyl group, a carboxylic acid group, a fluorinated
alcohol group, a sulfonic acid group, a sulfonamide group, a
sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene
group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a
bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group,
a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)-imide
group, a tris(alkylcarbonyl)methylene group or a
tris(alkylsulfonyl)methylene group.
[0246] Among these alkali-soluble groups, a carboxylic acid group,
a fluorinated alcohol group (preferably hexafluoroisopropanol) and
a sulfonic acid group are preferred.
[0247] As for the group capable of decomposing under the action of
an acid (acid-decomposable groups), a group obtained by
substituting the hydrogen atom of the above-described
alkali-soluble group with a group capable of desorbing under the
action of an acid is preferred.
[0248] Examples of the acid capable of desorbing under the action
of an acid include --C(R.sub.36)(R.sub.37)(R.sub.38),
--C(R.sub.36)(R.sub.37)(OR.sub.39) and
--C(R.sub.01)(R.sub.02)(OR.sub.39).
[0249] In the formulae, R.sub.36 to R.sub.39 each independently
represents an alkyl group, a cycloalkyl group, an aryl group, an
aralkyl group or an alkenyl group. R.sub.36 and R.sub.37 may be
bonded with each other to form a ring.
[0250] R.sub.01 and R.sub.02 each independently represents a
hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group,
an aralkyl group or an alkenyl group.
[0251] The acid-decomposable group is preferably a cumyl ester
group, an enol ester group, an acetal ester group, a tertiary alkyl
ester group or the like, more preferably a tertiary alkyl ester
group.
[0252] The positive resist composition of the present invention
containing a resin having a monocyclic or polycyclic alicyclic
hydrocarbon structure and being capable of increasing the
solubility in an alkali developer and decreasing the solubility in
an organic solvent under the action of an acid can be suitably used
when ArF excimer laser light is irradiated.
[0253] The resin having a monocyclic or polycyclic alicyclic
hydrocarbon structure and being capable of increasing the
solubility in an alkali developer and decreasing the solubility in
an organic solvent under the action of an acid (hereinafter
sometimes referred to as an "alicyclic hydrocarbon-based
acid-decomposable resin") is preferably a resin containing at least
one member selected from the group consisting of a repeating unit
having a alicyclic hydrocarbon-containing partial structure
represented by any one of the following formulae (pI) to (pV) and a
repeating unit represented by the following formula (II-AB).
##STR00005##
[0254] In formulae (pI) to (pV), R.sub.11 represents a methyl
group, an ethyl group, an n-propyl group, an isopropyl group, an
n-butyl group, an isobutyl group or a sec-butyl group.
[0255] Z represents an atomic group necessary for forming a
cycloalkyl group together with the carbon atom.
[0256] R.sub.12 to R.sub.16 each independently represents a linear
or branched alkyl group having a carbon number of 1 to 4 or a
cycloalkyl group, provided that at least one of R.sub.12 to
R.sub.14 or either one of R.sub.15 and R.sub.16 represents a
cycloalkyl group.
[0257] R.sub.17 to R.sub.21 each independently represents a
hydrogen atom, a linear or branched alkyl group having a carbon
number of 1 to 4 or a cycloalkyl group, provided that at least one
of R.sub.17 to R.sub.21 represents a cycloalkyl group and that
either one of R.sub.19 and R.sub.21 represents a linear or branched
alkyl group having a carbon number of 1 to 4 or a cycloalkyl
group.
[0258] R.sub.22 to R.sub.25 each independently represents a
hydrogen atom, a linear or branched alkyl group having a carbon
number of 1 to 4 or a cycloalkyl group, provided that at least one
of R.sub.22 to R.sub.25 represents a cycloalkyl group. R.sub.23 and
24 may combine with each other to form a ring.
##STR00006##
[0259] In formula (II-AB), R.sub.11' and R.sub.12' each
independently represents a hydrogen atom, a cyano group, a halogen
atom or an alkyl group.
[0260] Z' represents an atomic group for forming an alicyclic
structure containing two bonded carbon atoms (C--C).
[0261] Formula (II-AB) is preferably the following formula (II-AB1)
or (III-AB2):
##STR00007##
[0262] In formulae (II-AB1) and (II-AB2), R.sub.13' to R.sub.16'
each independently represents a hydrogen atom, a halogen atom, a
cyano group, --COOH, --COOR.sub.5, a group capable of decomposing
under the action of an acid, --C(.dbd.O)--X-A'--R.sub.17', an alkyl
group or a cycloalkyl group, and at least two members out of
R.sub.13' to R.sub.16' may combine to form a ring.
[0263] R.sub.5 represents an alkyl group, a cycloalkyl group or a
group having a lactone structure.
[0264] X represents an oxygen atom, a sulfur atom, --NH--,
--NHSO.sub.2-- or --NHSO.sub.2NH--.
[0265] A' represents a single bond or a divalent linking group.
[0266] R.sub.17' represents --COOH, --COOR.sub.5, --CN, a hydroxyl
group, an alkoxy group, --CO--NH--R.sub.6,
--CO--NH--SO.sub.2--R.sub.6 or a group having a lactone
structure.
[0267] R.sub.6 represents an alkyl group or a cycloalkyl group.
[0268] n represents 0 or 1.
[0269] In formulae (pI) to (pV), the alkyl group of R.sub.12 to
R.sub.25 is a linear or branched alkyl group having a carbon number
of 1 to 4.
[0270] The cycloalkyl group of R.sub.11 to R.sub.25 and the
cycloalkyl group formed by Z together with the carbon atom may be
monocyclic or polycyclic. Specific examples thereof include a group
having a carbon number of 5 or more and having a monocyclo,
bicyclo, tricyclo or tetracyclo structure or the like. The carbon
number thereof is preferably from 6 to 30, more preferably from 7
to 25. These cycloalkyl groups each may have a substituent.
[0271] Preferred examples of the cycloalkyl group include an
adamantyl group, a noradamantyl group, a decalin residue, a
tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl
group, a cedrol group, a cyclopentyl group, a cyclohexyl group, a
cycloheptyl group, a cyclooctyl group, a cyclodecanyl group and a
cyclododecanyl group. Among these, more preferred are an adamantyl
group, a norbornyl group, a cyclohexyl group, a cyclopentyl group,
a tetracyclododecanyl group and a tricyclodecanyl group.
[0272] Examples of the substituent which the alkyl group and
cycloalkyl group each may further have include an alkyl group
(having a carbon number of 1 to 4), a halogen atom, a hydroxyl
group, an alkoxy group (having a carbon number of 1 to 4), a
carboxyl group and an alkoxycarbonyl group (having a carbon number
of 2 to 6). Examples of the substituent which these alkyl group,
alkoxy group, alkoxycarbonyl group and the like each may further
have include a hydroxyl group, a halogen atom and an alkoxy
group.
[0273] The structures represented by formulae (pI) to (pV) each can
be used for the protection of an alkali-soluble group in the resin.
Examples of the alkali-soluble group include various groups known
in this technical field.
[0274] Specific examples thereof include a structure where the
hydrogen atom of a carboxylic acid group, a sulfonic acid group, a
phenol group or a thiol group is replaced by the structure
represented by any one of formulae (pI) to (pV). Among these,
preferred is a structure where the hydrogen atom of a carboxylic
acid group or a sulfonic acid group is replaced by the structure
represented by any one of formulae (pI) to (pV).
[0275] The repeating unit having an alkali-soluble group protected
by the structure represented by any one of formulae (pI) to (pV) is
preferably a repeating unit represented by the following formula
(pA):
##STR00008##
[0276] In the formula, R represents a hydrogen atom, a halogen atom
or a linear or branched alkyl group having a carbon number of 1 to
4, and the plurality of R's may be the same or different.
[0277] A represents a single bond, or a sole group or a combination
of two or more groups selected from the group consisting of an
alkylene group, an ether group, a thioether group, a carbonyl
group, an ester group, an amido group, a sulfonamido group, a
urethane group and a urea group. A is preferably a single bond.
[0278] Rp.sub.1 represents a group represented by any one of
formulae (pI) to (pV).
[0279] The repeating unit represented by formula (pA) is more
preferably a repeating unit comprising a
2-alkyl-2-adamantyl(meth)acrylate or a
dialkyl(l-adamantyl)methyl(meth)acrylate.
[0280] Specific examples of the repeating unit represented by
formula (pA) are set forth below, but the present invention is not
limited thereto.
[0281] (In the formulae, Rx represents H, CH.sub.3 or CH.sub.2OH,
and Rxa and Rxb each independently represents an alkyl group having
a carbon number of 1 to 4.)
##STR00009## ##STR00010## ##STR00011## ##STR00012##
##STR00013##
[0282] Examples of the halogen atom of R.sub.11' and R.sub.12' in
formula (II-AB) include a chlorine atom, a bromine atom, a fluorine
atom and an iodine atom.
[0283] The alkyl group of R.sub.1' and R.sub.12' includes a linear
or branched alkyl group having a carbon number of 1 to 10.
[0284] The atomic group of Z' for forming an alicyclic structure is
an atomic group for forming a repeating unit comprising an
alicyclic hydrocarbon which may have a substituent, in the resin.
Above all, an atomic group for forming a crosslinked alicyclic
structure to form a crosslinked alicyclic hydrocarbon repeating
unit is preferred.
[0285] Examples of the skeleton of the alicyclic hydrocarbon formed
are the same as those of the alicyclic hydrocarbon group of
R.sub.12 to R.sub.25 in formulae (pI) to (pV).
[0286] The skeleton of the alicyclic hydrocarbon may have a
substituent, and examples of the substituent include R.sub.13' to
R.sub.16' in formulae (II-AB1) and (II-AB2).
[0287] In the alicyclic hydrocarbon-based acid-decomposable resin
for use in the present invention, the group capable of decomposing
under the action of an acid may be contained in at least one
repeating unit out of the repeating unit having an alicyclic
hydrocarbon-containing partial structure represented by any one of
formulae (pI) to (pV), the repeating unit represented by formula
(II-AB), and the repeating unit comprising a copolymerization
component described later. The group capable of decomposing under
the action of an acid is preferably contained in the repeating unit
having an alicylcic hydrocarbon-containing partial structure
represented by any one of formulae (pI) to (pV).
[0288] Various substituents R.sub.13' to R.sub.16' in formulae
(II-AB1) and (II-AB2) may become substituents of the atomic group
for forming an alicyclic hydrocarbon structure in formula (II-AB)
or the atomic group Z for forming a crosslinked alicyclic
hydrocarbon structure.
[0289] Specific examples of the repeating units represented by
formulae (II-AB1) and (II-AB2) are set forth below, but the present
invention is not limited to these specific examples.
##STR00014## ##STR00015## ##STR00016## ##STR00017##
[0290] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention preferably has a lactone group. As for
the lactone group, any group may be used as long as it has a
lactone structure, but a group having a 5- to 7-membered ring
lactone structure is preferred. The 5- to 7-membered ring lactone
structure is preferably condensed with another ring structure in
the form of forming a bicyclo or spiro structure. The resin more
preferably contains a repeating unit containing a group having a
lactone structure represented by any one of the following formulae
(LC1-1) to (LC1-16). The group having a lactone structure may be
bonded directly to the main chain. Among these lactone structures,
preferred are groups represented by formulae (LC1-1), (LC1-4),
(LC1-5), (LC1-6), (LC1-13) and (LC1-14). By virtue of using a
specific lactone structure, the line edge roughness and development
defect are improved
##STR00018## ##STR00019##
[0291] The lactone structure moiety may or may not have a
substituent (Rb.sub.2). Preferred examples of the substituent
(Rb.sub.2) include an alkyl group having a carbon number of 1 to 8,
a cycloalkyl group having a carbon number of 4 to 7, an alkoxy
group having a carbon number of 1 to 8, an alkoxycarbonyl group
having a carbon number of 1 to 8, a carboxyl group, a halogen atom,
a hydroxyl group, a cyano group and an acid-decomposable group.
n.sub.2 represents an integer of 0 to 4. When n.sub.2 is an integer
of 2 or more, the plurality of substituents (Rb.sub.2) may be the
same or different and also, the plurality of substituents
(Rb.sub.2) may combine with each other to form a ring.
[0292] Examples of the repeating unit containing a group having a
lactone structure represented by any one of formulae (LCI-1) to
(LCI-16) include a repeating unit where at least one of R.sub.13'
to Rt.sub.16 in formula (II-AB1) or (II-AB2) has a group
represented by any one of formulae (LC1-1) to (LC1-16) (for
example, R.sub.5 of --COOR.sub.5 is a group represented by any one
of formulae (LC1-1) to (LC1-16)), and a repeating unit represented
by the following formula (AI):
##STR00020##
[0293] In formula (AI), Rb.sub.0 represents a hydrogen atom, a
halogen atom or an alkyl group having a carbon number of 1 to
4.
[0294] Preferred examples of the substituent which the alkyl group
of Rb.sub.0 may have include a hydroxyl group and a halogen
atom.
[0295] The halogen atom of Rb.sub.0 includes a fluorine atom, a
chlorine atom, a bromine atom and an iodine atom.
[0296] Rb.sub.0 is preferably a hydrogen atom or a methyl
group.
[0297] Ab represents a single bond, an alkylene group, a divalent
linking group having a monocyclic or polycyclic alicyclic
hydrocarbon structure, an ether group, an ester group, a carbonyl
group, a carboxyl group, or a divalent group comprising a
combination thereof, and is preferably a single bond or a linking
group represented by -Ab.sub.1-CO.sub.2--. Ab.sub.1 represents a
linear or branched alkylene group or a monocyclic or polycyclic
cycloalkylene group and is preferably a methylene group, an
ethylene group, a cyclohexylene group, an adamantyl group or a
norbornyl group.
[0298] V represents a group represented by any one of formulae
(LC1-1) to (LC1-16).
[0299] The repeating unit having a lactone structure usually has an
optical isomer, but any optical isomer may be used. One optical
isomer may be used alone or a mixture of a plurality of optical
isomers may be used. In the case of mainly using one optical
isomer, the optical purity (ee) thereof is preferably 90 or more,
more preferably 95 or more.
[0300] Specific examples of the repeating unit having a lactone
structure are set forth below, but the present invention is not
limited thereto.
[0301] (In the formulae, Rx is H, CH.sub.3, CH.sub.2OH or
CF.sub.3.)
##STR00021## ##STR00022## ##STR00023##
[0302] (In the formulae, Rx is H, CH.sub.3, CH.sub.2OH or
CF.sub.3.)
##STR00024## ##STR00025## ##STR00026##
[0303] (In the formulae, Rx is H, CH.sub.3, CH.sub.2OH or
CF.sub.3.)
##STR00027## ##STR00028##
[0304] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention preferably contains a repeating unit
containing an organic group having a polar group, more preferably a
repeating unit having an alicyclic hydrocarbon structure
substituted by a polar group. By virtue of this repeating unit, the
adhesion to substrate and the affinity for developer are enhanced.
The alicyclic hydrocarbon structure of the polar group-substituted
alicyclic hydrocarbon structure is preferably an adamantyl group, a
diamantyl group or a norbornane group. The polar group is
preferably a hydroxyl group or a cyano group.
[0305] The polar group-substituted alicyclic hydrocarbon structure
is preferably a partial structure represented by any one of the
following formulae (VIIa) to (VIId):
##STR00029##
[0306] In formulae (VIIa) to (VIIc), R.sub.2c to R.sub.4c each
independently represents a hydrogen atom, a hydroxyl group or a
cyano group, provided that at least one of R.sub.2c to R.sub.4c
represents a hydroxyl group or a cyano group. A structure where one
or two members out of R.sub.2c to R.sub.4c are a hydroxyl group
with the remaining being a hydrogen atom is preferred.
[0307] In formula (VIIa), it is more preferred that two members out
of R.sub.2c to R.sub.4c are a hydroxyl group and the remaining is a
hydrogen atom.
[0308] The repeating unit having a group represented by any one of
formulae (VIIa) to (VIId) includes a repeating unit where at least
one of R.sub.13' to R.sub.16' in formula (II-AB1) or (II-AB2) has a
group represented by formula (VII) (for example, R.sub.5 of
--COOR.sub.5 is a group represented by any one of formulae (VIIa)
to (VIId)), and repeating units represented by the following
formulae (AIIa) to (AIId):
##STR00030##
[0309] In formulae (AIIa) to (AIId), R.sub.1c represents a hydrogen
atom, a methyl group, a trifluoromethyl group or a hydroxymethyl
group.
[0310] R.sub.2c to R.sub.4c have the same meanings as R.sub.2c to
R.sub.4c in formulae (VIIa) to (VIIc).
[0311] Specific examples of the repeating unit having a structure
represented by any one of formulae (AIIa) to (AIId) are set forth
below, but the present invention is not limited thereto.
##STR00031## ##STR00032##
[0312] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention may contain a repeating unit
represented by the following formula (VIII):
##STR00033##
[0313] In formula (VIII), Z.sub.2 represents --O-- or
--N(R.sub.41)--. R.sub.41 represents a hydrogen atom, a hydroxyl
group, an alkyl group or --OSO.sub.2--R.sub.42. R.sub.42 represents
an alkyl group, a cycloalkyl group or a camphor residue. The alkyl
group of R.sub.41 and R.sub.42 may be substituted by a halogen atom
(preferably fluorine atom) or the like.
[0314] Specific examples of the repeating unit represented by
formula (VIII) are set forth below, but the present invention is
not limited thereto.
##STR00034##
[0315] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention preferably contains a repeating unit
having an alkali-soluble group, more preferably a repeating unit
having a carboxyl group. By virtue of containing this repeating
unit, the resolution increases in the usage of forming contact
holes. As for the repeating unit having a carboxyl group, a
repeating unit where a carboxyl group is directly bonded to the
resin main chain, such as repeating unit by an acrylic acid or a
methacrylic acid, a repeating unit where a carboxyl group is bonded
to the resin main chain through a linking group, and a repeating
unit where a carboxyl group is introduced into the terminal of the
polymer chain by using a polymerization initiator or chain transfer
agent having an alkali-soluble group at the polymerization, all are
preferred. The linking group may have a monocyclic or polycyclic
hydrocarbon structure. A repeating unit by an acrylic acid or a
methacrylic acid is more preferred.
[0316] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention may further contain a repeating unit
having from 1 to 3 groups represented by formula (F1). By virtue of
this repeating unit, the performance in terms of line edge
roughness is enhanced.
##STR00035##
[0317] In formula (F1), R.sub.50 to R.sub.55 each independently
represents a hydrogen atom, a fluorine atom or an alkyl group,
provided that at least one of R.sub.50 to R.sub.55 is a fluorine
atom or an alkyl group with at least one hydrogen atom being
substituted by a fluorine atom.
[0318] Rx represents a hydrogen atom or an organic group
(preferably an acid-decomposable protective group, an alkyl group,
a cycloalkyl group, an acyl group or an alkoxycarbonyl group).
[0319] The alkyl group of R.sub.50 to R.sub.55 may be substituted
by a halogen atom (e.g., fluorine), a cyano group or the like, and
the alkyl group is preferably an alkyl group having a carbon number
of 1 to 3, such as methyl group and trifluoromethyl group.
[0320] It is preferred that R.sub.50 to R.sub.55 all are a fluorine
atom.
[0321] The organic group represented by Rx is preferably an
acid-decomposable protective group or an alkyl, cycloalkyl, acyl,
alkylcarbonyl, alkoxycarbonyl, alkoxycarbonylmethyl, alkoxymethyl
or 1-alkoxyethyl group which may have a substituent.
[0322] The repeating unit having a group represented by formula
(F1) is preferably a repeating unit represented by the following
formula (F2):
##STR00036##
[0323] In formula (F2), Rx represents a hydrogen atom, a halogen
atom or an alkyl group having a carbon number of 1 to 4. Preferred
examples of the substituent which the alkyl group of Rx may have
include a hydroxyl group and a halogen atom.
[0324] Fa represents a single bond or a linear or branched alkylene
group and is preferably a single bond.
[0325] Fb represents a monocyclic or polycyclic hydrocarbon
group.
[0326] Fc represents a single bond or a linear or branched alkylene
group and is preferably a single bond or a methylene group.
[0327] F.sub.1 represents a group represented by formula (F1).
[0328] p.sub.1 represents a number of 1 to 3.
[0329] The cyclic hydrocarbon group in Fb is preferably a
cyclopentyl group, a cyclohexyl group or a norbornyl group.
[0330] Specific examples of the repeating unit having a group
represented by formula (F1) are set forth below, but the present
invention is not limited thereto.
##STR00037##
[0331] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention may further contain a repeating unit
having an alicyclic hydrocarbon structure and not exhibiting acid
decomposability. By virtue of this repeating unit, the dissolving
out of low molecular components from the resist film to the
immersion liquid at the immersion exposure can be reduced. Examples
of this repeating unit include 1-adamantyl(meth)acrylate,
tricyclodecanyl(meth)acrylate and cyclohexyl(meth)acrylate.
[0332] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention may contain, in addition to the
above-described repeating units, various repeating structural units
for the purpose of controlling dry etching resistance, suitability
for standard developer, adhesion to substrate, resist profile and
properties generally required of the resist, such as resolving
power, heat resistance and sensitivity.
[0333] Examples of such a repeating structural unit include, but
are not limited to, repeating structural units corresponding to the
monomers described below.
[0334] By virtue of such a repeating structural unit, the
performance required of the alicyclic hydrocarbon-based
acid-decomposable resin, particularly,
[0335] (1) solubility in coating solvent,
[0336] (2) film-forming property (glass transition point),
[0337] (3) solubility in positive or negative developer,
[0338] (4) film loss (selection of hydrophilic, hydrophobic or
alkali-soluble group),
[0339] (5) adhesion of unexposed area to substrate,
[0340] (6) dry etching resistance
and the like, can be subtly controlled.
[0341] Examples of the monomer include a compound having one
addition-polymerizable unsaturated bond selected from acrylic acid
esters, methacrylic acid esters, acrylamides, methacrylamides,
allyl compounds, vinyl ethers and vinyl esters.
[0342] Other than these, an addition-polymerizable unsaturated
compound copolymerizable with the monomers corresponding to the
above-described various repeating structural units may be
copolymerized.
[0343] In the alicyclic hydrocarbon-based acid-decomposable resin,
the molar ratio of respective repeating structural units contained
is appropriately determined to control the dry etching resistance
of resist, suitability for standard developer, adhesion to
substrate, resist profile and performances generally required of
the resist, such as resolving power, heat resistance and
sensitivity.
[0344] The preferred embodiment of the alicyclic hydrocarbon-based
acid-decomposable resin for use in the present invention includes
the followings:
[0345] (1) a resin containing a repeating unit having an alicyclic
hydrocarbon-containing partial structure represented by any one of
formulae (pI) to (pV) (side chain type), preferably a resin
containing a (meth)acrylate repeating unit having a structure
represented by any one of formulae (pI) to (pV), and
[0346] (2) a resin containing a repeating unit represented by
formula (II-AB) (main chain type).
[0347] The resin of (2) further includes:
[0348] (3) a resin having a repeating unit represented by formula
(II-AB), a maleic anhydride derivative and a (meth)acrylate
structure (hybrid type).
[0349] In the alicyclic hydrocarbon-based acid-decomposable resin,
the content of the repeating unit having an acid-decomposable group
is preferably from 10 to 60 mol %, more preferably from 20 to 50
mol %, still more preferably from 25 to 40 mol %, based on all
repeating structural units.
[0350] In the acid-decomposable resin, the content of the repeating
unit having an acid-decomposable group is preferably from 10 to 60
mol %, more preferably from 20 to 50 mol %, still more preferably
from 25 to 40 mol %, based on all repeating structural units.
[0351] In the alicyclic hydrocarbon-based acid-decomposable resin,
the content of the repeating unit having an alicyclic
hydrocarbon-containing partial structure represented by any one of
formulae (pI) to (pV) is preferably from 20 to 70 mol %, more
preferably from 20 to 50 mol %, still more preferably from 25 to 40
mol %, based on all repeating structural units.
[0352] In the alicyclic hydrocarbon-based acid-decomposable resin,
the content of the repeating unit represented by formula (II-AB) is
preferably from 10 to 60 mol %, more preferably from 15 to 55 mol
%, still more preferably from 20 to 50 mol %, based on all
repeating structural units.
[0353] In the acid-decomposable resin, the content of the repeating
unit having a lactone ring is preferably from 10 to 70 mol %, more
preferably from 20 to 60 mol %, still more preferably from 25 to 40
mol %, based on all repeating structural units.
[0354] In the acid-decomposable resin, the content of the repeating
unit having a polar group-containing organic group is preferably
from 1 to 40 mol %, more preferably from 5 to 30 mol %, still more
preferably from 5 to 20 mol %, based on all repeating structural
units.
[0355] The content of the repeating structural unit based on the
monomer as the further copolymerization component in the resin can
also be appropriately selected according to the desired resist
performance but in general, the content thereof is preferably 99
mol % or less, more preferably 90 mol % or less, still more
preferably 80 mol % or less, based on the total molar number of the
repeating structural unit having an alicyclic
hydrocarbon-containing partial structure represented by any one of
formulae (pI) to (pV) and the repeating unit represented by formula
(II-AB).
[0356] In the case of using the positive resist composition of the
present invention for exposure with ArF, the resin preferably has
no aromatic group in view of transparency to ArF light.
[0357] The alicyclic hydrocarbon-based acid-decomposable resin for
use in the present invention is preferably a resin where all
repeating units are composed of a (meth)acrylate-based repeating
unit. In this case, the repeating units may be all a
methacrylate-based repeating unit, all an acrylate-based repeating
unit, or all a mixture of methacrylate-based repeating
unit/acrylate-based repeating unit, but the content of the
acrylate-based repeating unit is preferably 50 mol % or less based
on all repeating units.
[0358] The alicyclic hydrocarbon-based acid-decomposable resin is
preferably a copolymer having three kinds of repeating unit, that
is, a (meth)acrylate-based repeating unit having a lactone ring, a
(meth)acrylate-based repeating unit having an organic group
substituted by either one of a hydroxyl group and a cyano group,
and a (meth)acrylate-based repeating unit having an
acid-decomposable group.
[0359] The copolymer is preferably a ternary copolymerization
polymer comprising from 20 to 50 mol % of the repeating unit having
an alicyclic hydrocarbon-containing partial structure represented
by any one of formulae (pI) to (pV), from 20 to 50 mol % of the
repeating unit having a lactone structure and from 5 to 30 mol % of
the repeating unit having a polar group-substituted alicyclic
hydrocarbon structure, or a quaternary copolymerization polymer
further comprising from 0 to 20 mol % of other repeating units.
[0360] In particular, the resin is preferably a ternary
copolymerization polymer comprising from 20 to 50 mol % of an
acid-decomposable group-containing repeating unit represented by
any one of the following formulae (ARA-1) to (ARA-7), from 20 to 50
mol % of a lactone group-containing repeating unit represented by
any one of the following formulae (ARL-1) to (ARL-6), and from 5 to
30 mol % of a repeating unit having a polar group-substituted
alicyclic hydrocarbon structure represented by any one of the
following formulae (ARH-1) to (ARH-3), or a quaternary
copolymerization polymer further comprising from 5 to 20 mol % of a
repeating unit containing a carboxyl group or a structure
represented by formula (F1) and a repeating unit having an
alicyclic hydrocarbon structure and not exhibiting acid
decomposability.
[0361] (In the formulae, Rxy.sub.1 represents a hydrogen atom or a
methyl group, Rxa.sub.1 and Rxb.sub.1 each independently represents
a methyl group or an ethyl group, and Rxc.sub.1 represents a
hydrogen atom or a methyl group).
##STR00038## ##STR00039## ##STR00040##
[0362] In the case of irradiating the acid-decomposable resin (A)
with KrF excimer laser light, electron beam, X-ray or high energy
beam at a wavelength of 50 nm or less (e.g., EUV), the
acid-decomposable resin preferably contains a hydroxystyrene-based
repeating unit such as repeating unit comprising hydroxystyrene.
The resin is more preferably a resin containing a
hydroxystyrene-based repeating unit and a repeating unit having an
acid-decomposable group (hereinafter sometimes referred to as a
"hydroxystyrene-based acid-decomposable resin"). As for the
repeating unit having an acid-decomposable group, a
hydroxystyrene-based repeating unit protected by an
acid-dissociatable group, and an acid-decomposable tertiary
alkyl(meth)acrylate-based repeating unit are preferred.
[0363] The hydroxystyrene-based repeating unit protected by an
acid-dissociatable group is preferably a repeating unit comprising
1-alkoxyethoxystyrene, tert-butylcarbonyloxystyrene or the like.
The alkyl group in the acid-decomposable tertiary
alkyl(meth)acrylate-based repeating unit includes a chain alkyl and
a monocyclic or polycyclic cycloalkyl group. The acid-decomposable
tertiary alkyl(meth)acrylate-based repeating unit is preferably a
repeating unit comprising a tert-butyl(meth)acrylate, a
2-alkyl-2-adamantyl(meth)acrylate, a
2-(1-adamantyl)-2-propyl(meth)acrylate, a
1-alkyl-1-cyclohexyl(meth)acrylate, a
1-alkyl-1-cyclopentyl(meth)acrylate or the like.
[0364] Specific examples of the hydroxystyrene-based
acid-decomposable resin are set forth below, but the present
invention is not limited thereto.
##STR00041## ##STR00042## ##STR00043## ##STR00044##
[0365] In these specific examples, tBu indicates a tert-butyl
group.
[0366] The content of the acid-decomposable group is expressed by
B/(B+S) using the number (B) of acid-decomposable groups in the
hydroxystyrene-based acid-decomposable resin and the number (S) of
alkali-soluble groups not protected by a group which leaves under
the action of an acid. The content is preferably from 0.01 to 0.7,
more preferably from 0.05 to 0.50, still more preferably from 0.05
to 0.40.
[0367] The acid-decomposable resin (A) for use in the present
invention can be synthesized by an ordinary method (for example,
radical polymerization). Examples of the synthesis method in
general include a batch polymerization method of dissolving the
monomer species and an initiator in a solvent and heating the
solution, thereby effecting the polymerization, and a dropping
polymerization method of adding dropwise a solution containing
monomer species and an initiator to a heated solvent over 1 to 10
hours. A dropping polymerization method is preferred. Examples of
the reaction solvent include tetrahydrofuran, 1,4-dioxane, ethers
such as diisopropyl ether, ketones such as methyl ethyl ketone and
methyl isobutyl ketone, an ester solvent such as ethyl acetate, an
amide solvent such as dimethylformamide and dimethylacetamide, and
a solvent capable of dissolving the composition of the present
invention, which is described later, such as propylene glycol
monomethyl ether acetate, propylene glycol monomethyl ether and
cyclohexanone. The polymerization is more preferably performed
using the same solvent as the solvent used in the resist
composition of the present invention. By the use of this solvent,
production of particles during storage can be suppressed.
[0368] The polymerization reaction is preferably performed in an
inert gas atmosphere such as nitrogen and argon. As for the
polymerization initiator, the polymerization is started using a
commercially available radical initiator (e.g., azo-based
initiator, peroxide). The radical initiator is preferably an
azo-based initiator, and an azo-based initiator having an ester
group, a cyano group or a carboxyl group is preferred. Preferred
examples of the initiator include azobisisobutyronitrile,
azobisdimethylvaleronitrile and dimethyl
2,2'-azobis(2-methyl-propionate). The initiator is added
additionally or in parts, if desired. After the completion of
reaction, the reactant is charged into a solvent, and the desired
polymer is recovered by a method such as powder or solid recovery.
The reaction concentration is from 5 to 50 mass %, preferably from
10 to 30 mass %, and the reaction temperature is usually from 10 to
150.degree. C., preferably from 30 to 120.degree. C., more
preferably from 60 to 100.degree. C. (In this specification, mass
ratio is equal to weight ratio.)
[0369] The purification may be performed by the same method as that
for the resin (C) described later, and a normal method, for
example, a liquid-liquid extraction method of applying water
washing or combining an appropriate solvent to remove residual
monomers or oligomer components, a purification method in a
solution sate, such as ultrafiltration of removing by extraction
only polymers having a molecular weight lower than a specific
molecular weight, a reprecipitation method of adding dropwise the
resin solution in a bad solvent to solidify the resin in the bad
solvent and thereby remove residual monomers or the like, or a
purification method in a solid state, such as washing of the resin
slurry with a bad solvent after separation by filtration, may be
applied.
[0370] The weight average molecular weight of the acid-decomposable
resin (A) for use in the present invention is preferably from 1,000
to 200,000, more preferably from 3,000 to 20,000, and most
preferably from 5,000 to 15,000, in terms of polystyrene by the GPC
method. When the weight average molecular weight is from 1,000 to
200,000, the heat resistance, dry etching resistance and
developability can be prevented from deterioration and also, the
deterioration in the film-forming property due to high viscosity
can be prevented.
[0371] Another preferred embodiment of the weight average molecular
weight of the acid-decomposable resin (A) for use in the present
invention is from 3,000 to 9,500 in terms of polystyrene by the GPC
method. When the weight average molecular weight is from 3,000 to
9,500, particularly the resist residue (hereinafter sometimes
referred to as "scum") is reduced and a better pattern can be
formed.
[0372] The dispersity (molecular weight distribution) is usually
from 1 to 5, preferably from 1 to 3, more preferably from 1.2 to
3.0, still more preferably from 1.2 to 2.0. As the dispersity is
smaller, the resolution and resist profile are more excellent, the
side wall of the resist pattern is smoother, and the property in
terms of roughness is more improved.
[0373] In the positive resist composition of the present invention,
the amount of all acid-decomposable resin (A) for use in the
present invention blended in the entire composition is preferably
from 50 to 99.9 mass %, more preferably from 60 to 99.0 mass %,
based on the entire solid content.
[0374] In the present invention, one resin may be used or a
plurality of resins may be used in combination.
[0375] The acid-decomposable resin (A) for use in the present
invention preferably contains no fluorine or silicon atom in view
of compatibility with the resin (D).
(B) Compound Capable of Generating an Acid Upon Irradiation with
Actinic Rays or Radiation
[0376] The positive resist composition of the present invention
contains a compound capable of generating an acid upon irradiation
with actinic rays or radiation (sometimes referred to as a
"photoacid generator" or "component (B)").
[0377] The photoacid generator which can be used may be
appropriately selected from a photoinitiator for photocationic
polymerization, a photoinitiator for photoradical polymerization, a
photo-decoloring agent for coloring matters, a photo-discoloring
agent, a known compound used for microresist or the like and
capable of generating an acid upon irradiation with actinic rays or
radiation, and a mixture thereof.
[0378] Examples thereof include a diazonium salt, a phosphonium
salt, a sulfonium salt, an iodonium salt, an imidosulfonate, an
oxime sulfonate, a diazodisulfone, a disulfone and an o-nitrobenzyl
sulfonate.
[0379] Also, a compound where such a group or compound capable of
generating an acid upon irradiation with actinic rays or radiation
is introduced into the main or side chain of the polymer, for
example, compounds described in U.S. Pat. No. 3,849,137, German
Patent 3,914,407, JP-A-63-26653, JP-A-55-164824, JP-A-62-69263,
JP-A-63-146038, JP-A-63-163452, JP-A-62-153853 and JP-A-63-146029,
may be used.
[0380] Furthermore, compounds capable of generating an acid by the
effect of light described, for example, in U.S. Pat. No. 3,779,778
and European Patent 126,712 may also be used.
[0381] Out of the compounds capable of generating an acid upon
irradiation with actinic rays or radiation, preferred are the
compounds represented by the following formulae (ZI), (ZII) and
(ZIII):
##STR00045##
[0382] In formula (ZI), R.sub.201, R.sub.202 and R.sub.203 each
independently represents an organic group.
[0383] X' represents a non-nucleophilic anion, and preferred
examples thereof include sulfonate anion, carboxylate anion,
bis(alkylsulfonyl)amide anion, tris(alkylsulfonyl)methide anion,
BF.sub.4.sup.-, PF.sub.6.sup.- and SbF.sub.6.sup.-. The anion is
preferably an organic anion containing a carbon atom.
[0384] The preferred organic anion includes organic anions
represented by the following formulae:
##STR00046##
[0385] In the formulae, Rc.sub.1 represents an organic group.
[0386] The organic group of Rc.sub.1 includes an organic group
having a carbon number of 1 to 30, and preferred examples thereof
include an alkyl group which may be substituted, an aryl group, and
a group where a plurality of these groups are connected through a
single bond or a linking group such as --O--, --CO.sub.2--, --S--,
--SO.sub.3-- and --SO.sub.2N(Rd.sub.1)--. Rd.sub.1 represents a
hydrogen atom or an alkyl group.
[0387] Rc.sub.3, Rc.sub.4 and Rc.sub.5 each independently
represents an organic group. Preferred organic groups of Rc.sub.3,
Rc.sub.4 and Re.sub.5 are the same as preferred organic groups in
Rc.sub.1. The organic group is most preferably a perfluoroalkyl
group having a carbon number of 1 to 4.
[0388] Rc.sub.3 and Rc.sub.4 may combine to form a ring. The group
formed after Rc.sub.3 and Rc.sub.4 are combined includes an
alkylene group and an arylene group, and a perfluoroalkylene group
having a carbon number of 2 to 4 is preferred.
[0389] The organic group of Rc.sub.1 and Rc.sub.3 to Rc.sub.5 is
particularly preferably an alkyl group with the 1-position being
substituted by a fluorine atom or a fluoroalkyl group, or a phenyl
group substituted by a fluorine atom or a fluoroalkyl group. By
virtue of having a fluorine atom or a fluoroalkyl group, the
acidity of the acid generated upon irradiation with light increases
and the sensitivity is enhanced. Also, when Rc.sub.3 and Rc.sub.4
are combined to form a ring, the acidity of the acid generated upon
irradiation with light increases and the sensitivity is
enhanced.
[0390] The carbon number of the organic group as R.sub.201,
R.sub.202 and R.sub.203 is generally from 1 to 30, preferably from
1 to 20.
[0391] Two members out of R.sub.201 to R.sub.203 may combine to
form a ring structure, and the ring may contain an oxygen atom, a
sulfur atom, an ester bond, an amide bond or a carbonyl group.
Examples of the group formed after two members out of R.sub.201 to
R.sub.203 are combined include an alkylene group (e.g., butylene,
pentylene).
[0392] Specific examples of the organic group as R.sub.201,
R.sub.202 and R.sub.203 include corresponding groups in the
compounds (ZI-1), (ZI-2) and (ZI-3) which are described later.
[0393] The compound may be a compound having a plurality of
structures represented by formula (ZI). For example, the compound
may be a compound having a structure that at least one of R.sub.201
to R.sub.203 in the compound represented by formula (ZI) is bonded
to at least one of R.sub.201 to R.sub.203 in another compound
represented by formula (ZI).
[0394] The component (ZI) is more preferably a compound (ZI-1),
(ZI-2) or (ZI-3) described below.
[0395] The compound (ZI-1) is an arylsulfonium compound where at
least one of R.sub.201 to R.sub.203 in formula (Z1) is an aryl
group, that is, a compound having an arylsulfonium as the
cation.
[0396] In the arylsulfonium compound, R.sub.201 to R.sub.203 all
may be an aryl group or a part of R.sub.201 to R.sub.203 may be an
aryl group with the remaining being an alkyl group or a cycloalkyl
group.
[0397] Examples of the arylsulfonium compound include a
triarylsulfonium compound, a diarylalkylsulfonium compound, an
aryldialkylsulfonium compound, a diarylcycloalkyl-sulfonium
compound and an aryldicycloalkylsulfonium compound.
[0398] The aryl group in the arylsulfonium compound is preferably
an aryl group such as phenyl group and naphthyl group, or a
heteroaryl group such as indole residue and pyrrole residue, more
preferably a phenyl group or an indole residue. In the case where
the arylsulfonium compound has two or more aryl groups, these two
or more aryl groups may be the same or different.
[0399] The alkyl group which is present, if desired, in the
arylsulfonium compound is preferably a linear or branched alkyl
group having a carbon number of 1 to 15, and examples thereof
include a methyl group, an ethyl group, a propyl group, an n-butyl
group, a sec-butyl group and a tert-butyl group.
[0400] The cycloalkyl group which is present, if desired, in the
arylsulfonium compound is preferably a cycloalkyl group having a
carbon number of 3 to 15, and examples thereof include a
cyclopropyl group, a cyclobutyl group and a cyclohexyl group.
[0401] The aryl group, alkyl group and cycloalkyl group of
R.sub.201 to R.sub.203 each may have, as the substituent, an alkyl
group (for example, an alkyl group having a carbon number of 1 to
15), a cycloalkyl group (for example, a cycloalkyl group having a
carbon number of 3 to 15), an aryl group (for example, an aryl
group having a carbon number of 6 to 14), an alkoxy group (for
example, an alkoxy group having a carbon number of 1 to 15), a
halogen atom, a hydroxyl group or a phenylthio group. The
substituent is preferably a linear or branched alkyl group having a
carbon number of 1 to 12, a cycloalkyl group having a carbon number
of 3 to 12, or a linear, branched or cyclic alkoxy group having a
carbon number of 1 to 12, more preferably an alkyl group having a
carbon number of 1 to 4 or an alkoxy group having a carbon number
of 1 to 4. The substituent may be substituted to any one of three
members R.sub.201 to R.sub.203 or may be substituted to all of
these three members. In the case where R.sub.201 to R.sub.203 are
an aryl group, the substituent is preferably substituted at the
p-position of the aryl group.
[0402] The compound (ZI-2) is described below. The compound (ZI-2)
is a compound where R.sub.201 to R.sub.203 in formula (ZI) each
independently represents an aromatic ring-free organic group. The
aromatic ring as used herein includes an aromatic ring containing a
heteroatom.
[0403] The aromatic ring-free organic group as R.sub.201 to
R.sub.203 generally has a carbon number of 1 to 30, preferably from
1 to 20.
[0404] R.sub.201 to R.sub.203 each is independently preferably an
alkyl group, a cycloalkyl group, an allyl group or a vinyl group,
more preferably a linear, branched or cyclic 2-oxoalkyl group or an
alkoxycarbonylmethyl group, still more preferably a linear or
branched 2-oxoalkyl group.
[0405] The alkyl group as R.sub.201 to R.sub.203 may be either
linear or branched and includes a linear or branched alkyl group
preferably having a carbon number of 1 to 10 (e.g., methyl, ethyl,
propyl, butyl, pentyl). The alkyl group as R.sub.201 to R.sub.203
is preferably a linear or branched 2-oxoalkyl group or an
alkoxycarbonylmethyl group.
[0406] The cycloalkyl group as R.sub.201 to R.sub.203 includes a
cycloalkyl group preferably having a carbon number of 3 to 10
(e.g., cyclopentyl, cyclohexyl, norbornyl). The cycloalkyl group as
R.sub.201 to R.sub.203 is preferably a cyclic 2-oxoalkyl group.
[0407] The linear, branched or cyclic 2-oxoalkyl group as R.sub.201
to R.sub.203 is preferably a group having >C.dbd.O at the
2-position of the above-described alkyl or cycloalkyl group.
[0408] The alkoxy group in the alkoxycarbonylmethyl group as
R.sub.201 to R.sub.203 includes an alkoxy group preferably having a
carbon number of 1 to 5 (e.g., methoxy, ethoxy, propoxy, butoxy,
pentoxy).
[0409] R.sub.201 to R.sub.203 each may be further substituted by a
halogen atom, an alkoxy group (for example, an alkoxy group having
a carbon number of 1 to 5), a hydroxyl group, a cyano group or a
nitro group.
[0410] The compound (ZI-3) is a compound represented by the
following formula (ZI-3), and this is a compound having a
phenacylsulfonium salt structure.
##STR00047##
[0411] In formula (ZI-3), R.sub.1c to R.sub.5c each independently
represents a hydrogen atom, an alkyl group, a cycloalkyl group, an
alkoxy group or a halogen atom.
[0412] R.sub.6c and R.sub.7c each independently represents a
hydrogen atom, an alkyl group or a cycloalkyl group.
[0413] R.sub.x and R.sub.y each independently represents an alkyl
group, a cycloalkyl group, an allyl group or a vinyl group.
[0414] Any two or more members out of R.sub.1c to R.sub.7c or a
pair of R.sub.x and R.sub.y may combine with each other to form a
ring structure, and the ring structure may contain an oxygen atom,
a sulfur atom, an ester bond or an amide bond. Examples of the
group formed after any two or more members out of R.sub.1c to
R.sub.7c or a pair of R.sub.x and R.sub.y are combined include a
butylene group and a pentylene group.
[0415] X.sup.- represents a non-nucleophilic anion, and examples
thereof are the same as those of the non-nucleophilic anion of
X.sup.- in formula (ZI).
[0416] The alkyl group as R.sub.1c to R.sub.7c may be linear or
branched and includes, for example, a linear or branched alkyl
group having a carbon number of 1 to 20, preferably a linear or
branched alkyl group having a carbon number of 1 to 12 (for
example, a methyl group, an ethyl group, a linear or branched
propyl group, a linear or branched butyl group, and a linear or
branched pentyl group).
[0417] The cycloalkyl group as R.sub.1c to R.sub.7c includes a
cycloalkyl group preferably having a carbon number of 3 to 8 (e.g.,
cyclopentyl, cyclohexyl).
[0418] The alkoxy group as R.sub.1c to R.sub.5c may be linear,
branched or cyclic and includes, for example, an alkoxy group
having a carbon number of 1 to 10, preferably a linear or branched
alkoxy group having a carbon number of 1 to 5 (for example, a
methoxy group, an ethoxy group, a linear or branched propoxy group,
a linear or branched butoxy group, and a linear or branched pentoxy
group), and a cyclic alkoxy group having a carbon number of 3 to 8
(e.g., cyclopentyloxy, cyclohexyloxy).
[0419] A compound where any one of R.sub.1c to R.sub.5c is a linear
or branched alkyl group, a cycloalkyl group or a linear, branched
or cyclic alkoxy group is preferred, and a compound where the sum
of carbon numbers of R.sub.1c to R.sub.5c is from 2 to 15 is more
preferred. By virtue of this construction, the solubility in a
solvent is more enhanced and generation of particles during storage
is suppressed.
[0420] The alkyl group as R.sub.x and R.sub.y is the same as the
alkyl group of R.sub.1c to R.sub.7c. The alkyl group as R.sub.x and
R.sub.y is preferably a linear or branched 2-oxoalkyl group or an
alkoxycarbonylmethyl group.
[0421] The cycloalkyl group as R.sub.x and R.sub.y is the same as
the cycloalkyl group of R.sub.1c to R.sub.7c. The cycloalkyl group
as R.sub.x to R.sub.y is preferably a cyclic 2-oxoalkyl group.
[0422] The linear, branched or cyclic 2-oxoalkyl group includes a
group having >C.dbd.O at the 2-position of the alkyl group or
cycloalkyl group as R.sub.1c to R.sub.7c.
[0423] The alkoxy group in the alkoxycarbonylmethyl group is the
same as the alkoxy group of R.sub.1c to R.sub.5c.
[0424] R.sub.x and R.sub.y each is preferably an alkyl group having
a carbon number of 4 or more, more preferably 6 or more, still more
preferably 8 or more.
[0425] In formulae (ZII) and (ZIII), R.sub.204 to R.sub.207 each
independently represents an aryl group, an alkyl group or a
cycloalkyl group.
[0426] The aryl group of R.sub.204 to R.sub.207 is preferably a
phenyl group or a naphthyl group, more preferably a phenyl
group.
[0427] The alkyl group of R.sub.204 to R.sub.207 may be linear or
branched and includes a linear or branched alkyl group preferably
having a carbon number of 1 to 10 (e.g., methyl, ethyl, propyl,
butyl, pentyl).
[0428] The cycloalkyl group of R.sub.204 to R.sub.207 includes a
cycloalkyl group preferably having a carbon number of 3 to 10
(e.g., cyclopentyl, cyclohexyl, norbornyl).
[0429] R.sub.204 to R.sub.207 each may have a substituent. Examples
of the substituent which R.sub.204 to R.sub.207 each may have
include an alkyl group (for example, an alkyl group having a carbon
number of 1 to 15), a cycloalkyl group (for example, a cycloalkyl
group having a carbon number of 3 to 15), an aryl group (for
example, an aryl group having a carbon number of 6 to 15), an
alkoxy group (for example, an alkoxy group having a carbon number
of 1 to 15), a halogen atom, a hydroxyl group and a phenylthio
group.
[0430] X.sub.- represents a non-nucleophilic anion and is the same
as the non-nucleophilic anion of X.sup.- in formula (ZI).
[0431] Out of the compounds capable of generating an acid upon
irradiation with actinic rays or radiation, preferred compounds
further include the compounds represented by the following formulae
(ZIV), (ZV) and (ZVI):
##STR00048##
[0432] In formulae (ZIV) to (ZVI), Ar.sub.3 and Ar.sub.4 each
independently represents an aryl group.
[0433] R.sub.206 represents an alkyl group or an aryl group.
[0434] R.sub.207 and R.sub.208 each independently represents an
alkyl group, an aryl group or an electron-withdrawing group.
R.sub.207 is preferably an aryl group.
[0435] R.sub.208 is preferably an electron-withdrawing group, more
preferably a cyano group or a fluoroalkyl group.
[0436] A represents an alkylene group, an alkenylene group or an
arylene group.
[0437] The compound capable of generating an acid upon irradiation
with actinic rays or radiation is preferably a compound represented
by any one of formulae (ZI) to (ZIII).
[0438] The compound (B) is preferably a compound capable of
generating a fluorine atom-containing aliphatic sulfonic acid or
fluorine atom-containing benzenesulfonic acid upon irradiation with
actinic rays or radiation.
[0439] The compound (B) preferably has a triphenylsulfonium
structure.
[0440] The compound (B) is preferably a triphenylsulfonium salt
compound having a fluorine-unsubstituted alkyl or cycloalkyl group
in the cation moiety.
[0441] Particularly preferred examples out of the compounds capable
of generating an acid upon irradiation with actinic rays or
radiation are set forth below.
##STR00049## ##STR00050## ##STR00051## ##STR00052## ##STR00053##
##STR00054## ##STR00055## ##STR00056## ##STR00057## ##STR00058##
##STR00059## ##STR00060## ##STR00061##
[0442] One of these photoacid generators may be used alone, or two
or more species thereof may be used in combination. In the case of
using two or more species in combination, compounds capable of
generating two kinds of organic acids differing in the total atom
number except for hydrogen atom by 2 or more are preferably
combined.
[0443] The content of the photoacid generator is preferably from
0.1 to 20 mass %, more preferably from 0.5 to 10 mass %, still more
preferably from 1 to 7 mass %, based on the entire solid content of
the positive resist composition.
(C) Solvent
[0444] Examples of the solvent which can be used for dissolving
respective components described above to prepare a positive resist
composition include an organic solvent such as alkylene glycol
monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl
lactate, alkyl alkoxypropionate, cyclic lactone having a carbon
number of 4 to 10, monoketone compound having a carbon number of 4
to 10 which may contain a ring, alkylene carbonate, alkyl
alkoxyacetate and alkyl pyruvate.
[0445] Preferred examples of the alkylene glycol monoalkyl ether
carboxylate include propylene glycol monomethyl ether acetate,
propylene glycol monoethyl ether acetate, propylene glycol
monopropyl ether acetate, propylene glycol monobutyl ether acetate,
propylene glycol monomethyl ether propionate, propylene glycol
monoethyl ether propionate, ethylene glycol monomethyl ether
acetate and ethylene glycol monoethyl ether acetate.
[0446] Preferred examples of the alkylene glycol monoalkyl ether
include propylene glycol monomethyl ether, propylene glycol
monoethyl ether, propylene glycol monopropyl ether, propylene
glycol monobutyl ether, ethylene glycol monomethyl ether and
ethylene glycol monoethyl ether.
[0447] Preferred examples of the alkyl lactate include methyl
lactate, ethyl lactate, propyl lactate and butyl lactate.
[0448] Preferred examples of the alkyl alkoxypropionate include
ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl
3-ethoxypropionate and ethyl 3-methoxypropionate.
[0449] Preferred examples of the cyclic lactone having a carbon
number of 4 to 10 include .beta.-propiolactone,
.beta.-butyrolactone, .gamma.-butyrolactone,
.alpha.-methyl-.gamma.-butyrolactone,
.beta.-methyl-.gamma.-butyrolactone, .gamma.-valerolactone,
.gamma.-caprolactone, .gamma.-octanoic lactone and
.alpha.-hydroxy-.gamma.-butyrolactone.
[0450] Preferred examples of the monoketone compound having a
carbon number of 4 to 10 which may contain a ring include
2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,
3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-methyl-3-pentanone,
4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone,
2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone,
5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,
2-methyl-3-heptanone, 5-methyl-3-heptanone,
2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone,
3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone,
5-hexen-2-one, 3-penten-2-one, cyclopentanone,
2-methylcyclopentanone, 3-methylcyclopentanone,
2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,
cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,
4-ethylcyclohexanone, 2,2-dimethylcyclohexanone,
2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone,
cycloheptanone, 2-methylcycloheptanone and
3-methylcycloheptanone.
[0451] Preferred examples of the alkylene carbonate include
propylene carbonate, vinylene carbonate, ethylene carbonate and
butylene carbonate.
[0452] Preferred examples of the alkyl alkoxyacetate include
2-methoxyethyl acetate, 2-ethoxyethyl acetate,
2-(2-ethoxyethoxy)ethyl acetate, 3-methoxy-3-methylbutyl acetate
and 1-methoxy-2-propyl acetate.
[0453] Preferred examples of the alkyl pyruvate include methyl
pyruvate, ethyl pyruvate and propyl pyruvate.
[0454] The solvent which can be preferably used is a solvent having
a boiling point of 130.degree. C. or more at ordinary temperature
under atmospheric pressure, and specific examples thereof include
cyclopentanone, .gamma.-butyrolactone, cyclohexanone, ethyl
lactate, ethylene glycol monoethyl ether acetate, propylene glycol
monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate,
2-ethoxyethyl acetate, 2-(2-ethoxyethoxy)ethyl acetate and
propylene carbonate.
[0455] In the present invention, one of these solvents may be used
alone, or two or more species thereof may be used in
combination.
[0456] In the present invention, a mixed solvent prepared by mixing
a solvent containing a hydroxyl group in the structure and a
solvent not containing a hydroxyl group may be used as the organic
solvent.
[0457] Examples of the solvent containing a hydroxyl group include
ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol
monoethyl ether, propylene glycol, propylene glycol monomethyl
ether, propylene glycol monoethyl ether and ethyl lactate. Among
these, propylene glycol monomethyl ether and ethyl lactate are
preferred.
[0458] Examples of the solvent not containing a hydroxyl group
include propylene glycol monomethyl ether acetate, ethyl
ethoxypropionate, 2-heptanone, .gamma.-butyrolactone,
cyclohexanone, butyl acetate, N-methylpyrrolidone,
N,N-dimethylacetamide and dimethylsulfoxide. Among these, propylene
glycol monomethyl ether acetate, ethyl ethoxy-propionate,
2-heptanone, .gamma.-butyrolactone, cyclohexanone and butyl acetate
are preferred, and propylene glycol monomethyl ether acetate, ethyl
ethoxypropionate and 2-heptanone are most preferred.
[0459] The mixing ratio (by mass) of the solvent containing a
hydroxyl group and the solvent not containing a hydroxyl group is
from 1/99 to 99/1, preferably from 10/90 to 90/10, more preferably
from 20/80 to 60/40. A mixed solvent in which the solvent not
containing a hydroxyl group is contained in an amount of 50 mass %
or more is preferred in view of coating uniformity.
[0460] The solvent is preferably a mixed solvent of two or more
species including propylene glycol monomethyl acetate.
(D) Resin Having at Least Either a Fluorine Atom or a Silicon
Atom
[0461] The positive resist composition of the present invention
preferably contains (D) a resin having at least either a fluorine
atom or a silicon atom.
[0462] In the resin (D), the fluorine atom or silicon atom may be
present in the main chain of the resin or may be substituted to the
side chain.
[0463] The resin (D) is preferably a resin having a fluorine
atom-containing alkyl group, a fluorine atom-containing cycloalkyl
group or a fluorine atom-containing aryl group, as a fluorine
atom-containing partial structure.
[0464] The fluorine atom-containing alkyl group (preferably having
a carbon number of 1 to 10, more preferably from 1 to 4) is a
linear or branched alkyl group with at least one hydrogen atom
being substituted by a fluorine atom and may further have another
substituent.
[0465] The fluorine atom-containing cycloalkyl group is a
monocyclic or polycyclic cycloalkyl group with at least one
hydrogen atom being substituted by a fluorine atom and may further
have another substituent.
[0466] The fluorine atom-containing aryl group is an aryl group
(e.g., phenyl, naphthyl) with at least one hydrogen atom being
substituted by a fluorine atom and may further have another
substituent.
[0467] Specific examples of the fluorine atom-containing alkyl
group, fluorine atom-containing cycloalkyl group and fluorine
atom-containing aryl group are set forth below, but the present
invention is not limited thereto.
##STR00062##
[0468] In formulae (F2) to (F4), R.sub.57 to R.sub.68 each
independently represents a hydrogen atom, a fluorine atom or an
alkyl group, provided that at least one of R.sub.57 to R.sub.61, at
least one of R.sub.62 to R.sub.64 and at least one of R.sub.65 to
R.sub.68 are a fluorine atom or an alkyl group (preferably having a
carbon number of 1 to 4) with at least one hydrogen atom being
substituted by a fluorine atom. It is preferred that R.sub.57 to
R.sub.61 and R.sub.65 to R.sub.67 all are a fluorine atom.
R.sub.62, R.sub.63 and R.sub.68 each is preferably an alkyl group
(preferably having a carbon number of 1 to 4) with at least one
hydrogen atom being substituted by a fluorine atom, more preferably
a perfluoroalkyl group having a carbon number of 1 to 4. R.sub.62
and R.sub.63 may combine with each other to form a ring.
[0469] Specific examples of the group represented by formula (F2)
include p-fluorophenyl group, pentafluorophenyl group and
3,5-di(trifluoromethyl)phenyl group.
[0470] Specific examples of the group represented by formula (F3)
include trifluoroethyl group, pentafluoropropyl group,
pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl
group, heptafluoroisopropyl group, hexafluoro(2-methyl)isopropyl
group, nonafluorobutyl group, octafluoroisobutyl group,
nonafluorohexyl group, nonafluoro-tert-butyl group,
perfluoroisopentyl group, perfluorooctyl group,
perfluoro(trimethyl)hexyl group, 2,2,3,3-tetrafluorocyclobutyl
group and perfluorocyclohexyl group. Among these,
hexafluoroisopropyl group, heptafluoroisopropyl group,
hexafluoro(2-methyl)isopropyl group, octafluoroisobutyl group,
nonafluoro-tert-butyl group and perfluoroisopentyl group are
preferred, and hexafluoroisopropyl group and heptafluoroisopropyl
group are more preferred.
[0471] Specific examples of the group represented by formula (F4)
include --C(CF.sub.3).sub.2OH, --C(C.sub.2F.sub.5).sub.2OH,
--C(CF.sub.3)(CH.sub.3)OH and --CH(CF.sub.3)OH, with
--C(CF.sub.3).sub.2OH being preferred.
[0472] The resin (D) is preferably a resin having an alkylsilyl
structure (preferably a trialkylsilyl group) or a cyclic siloxane
structure, as a silicon atom-containing partial structure.
[0473] Specific examples of the alkylsilyl structure and cyclic
siloxane structure include the groups represented by the following
formulae (CS-1) to (CS-3):
##STR00063##
[0474] In formulae (CS-1) to (CS-3), R.sub.12 to R.sub.26 each
independently represents a linear or branched alkyl group
(preferably having a carbon number of 1 to 20) or a cycloalkyl
group (preferably having a carbon number of 3 to 20).
[0475] L.sub.3 to L.sub.5 each represents a single bond or a
divalent linking group. The divalent linking group is a sole group
or a combination of two or more groups selected from the group
consisting of an alkylene group, a phenyl group, an ether group, a
thioether group, a carbonyl group, an ester group, an amide group,
a urethane group and a urea group. n represents an integer of 1 to
5.
[0476] The resin (D) is preferably a resin containing at least one
member selected from the group consisting of repeating units
represented by the following formulae (C-I) to (C-V):
##STR00064##
[0477] In formulae (C-I) to (C-V), R.sub.1 to R.sub.3 each
independently represents a hydrogen atom, a fluorine atom, a linear
or branched alkyl group having a carbon number of 1 to 4, or a
linear or branched fluorinated alkyl group having a carbon number
of 1 to 4.
[0478] W.sub.1 and W.sub.2 each represents an organic group having
at least either a fluorine atom or a silicon atom.
[0479] R.sub.4 to R.sub.7 each independently represents a hydrogen
atom, a fluorine atom, a linear or branched alkyl group having a
carbon number of 1 to 4, or a linear or branched fluorinated alkyl
group having a carbon number of 1 to 4, provided that at least one
of R.sub.4 to R.sub.7 represents a fluorine atom. R.sub.4 and
R.sub.5, or R.sub.6 and R.sub.7 may form a ring.
[0480] R.sub.8 represents a hydrogen atom or a linear or branched
alkyl group having a carbon number of 1 to 4.
[0481] R.sub.9 represents a linear or branched alkyl group having a
carbon number of 1 to 4, or a linear or branched fluorinated alkyl
group having a carbon number of 1 to 4.
[0482] L.sub.1 and L.sub.2 each represents a single bond or a
divalent linking group and is the same as L.sub.3 to L.sub.5
above.
[0483] Q represents a monocyclic or polycyclic aliphatic group,
that is, an atomic group for forming an alicyclic structure,
including the two bonded carbon atoms (C--C).
[0484] R.sub.30 and R.sub.31 each independently represents a
hydrogen or fluorine atom.
[0485] R.sub.32 and R.sub.33 each independently represents an alkyl
group, a cycloalkyl group, a fluorinated alkyl group or a
fluorinated cycloalkyl group.
[0486] Here, the repeating unit represented by formula (C-V) has at
least one fluorine atom in at least one member out of R.sub.30,
R.sub.31, R.sub.32 and R.sub.33.
[0487] The resin (D) preferably has a repeating unit represented by
formula (C-I), more preferably a repeating unit represented by any
one of the following formulae (C-Ia) to (C-Id):
##STR00065##
[0488] In formulae (C-Ia) to (C-Id), R.sub.10 and R.sub.11 each
represents a hydrogen atom, a fluorine atom, a linear or branched
alkyl group having a carbon number of 1 to 4, or a linear or
branched fluorinated alkyl group having a carbon number of 1 to
4.
[0489] W.sub.3 to W.sub.6 each represents an organic group having
one or more of at least either a fluorine atom or a silicon
atom.
[0490] When W.sub.1 to W.sub.6 are an organic group having a
fluorine atom, the organic group is preferably a fluorinated linear
or branched alkyl or cycloalkyl group having a carbon number of 1
to 20, or a fluorinated linear, branched or cyclic alkyl ether
group having a carbon number of 1 to 20.
[0491] Examples of the fluorinated alkyl group of W.sub.1 to
W.sub.6 include a trifluoroethyl group, a pentafluoropropyl group,
a hexafluoroisopropyl group, a hexafluoro(2-methyl)isopropyl group,
a heptafluorobutyl group, a heptafluoroisopropyl group, an
octafluoroisobutyl group, a nonafluorohexyl group, a
nonafluoro-tert-butyl group, a perfluoroisopentyl group, a
perfluorooctyl group and a perfluoro(trimethyl)hexyl group.
[0492] When W.sub.1 to W.sub.6 are an organic group having a
silicon atom, the organic group preferably has an alkylsilyl
structure or a cyclic siloxane structure. Specific examples thereof
include the groups represented by formulae (CS-1) to (CS-3).
[0493] Specific examples of the repeating unit represented by
formula (C-I) are set forth below. X represents a hydrogen atom,
--CH.sub.3, --F or --CF.sub.3.
##STR00066## ##STR00067## ##STR00068##
[0494] The resin (D) is preferably any one resin selected from the
following (D-1) to (D-6):
[0495] (D-1) a resin containing (a) a repeating unit having a
fluoroalkyl group (preferably having a carbon number of 1 to 4),
more preferably containing only the repeating unit (a),
[0496] (D-2) a resin containing (b) a repeating unit having a
trialkylsilyl group or a cyclic siloxane structure, more preferably
containing only the repeating unit (b),
[0497] (D-3) a resin containing (a) a repeating unit having a
fluoroalkyl group (preferably having a carbon number of 1 to 4) and
(c) a repeating unit having a branched alkyl group (preferably
having a carbon number of 4 to 20), a cycloalkyl group (preferably
having a carbon number of 4 to 20), a branched alkenyl group
(preferably having a carbon number of 4 to 20), a cycloalkenyl
group (preferably having a carbon number of 4 to 20) or an aryl
group (preferably having a carbon number of 4 to 20), more
preferably a copolymerization resin of the repeating unit (a) and
the repeating unit (c),
[0498] (D-4) a resin containing (b) a repeating unit having a
trialkylsilyl group or a cyclic siloxane structure and (c) a
repeating unit having a branched alkyl group (preferably having a
carbon number of 4 to 20), a cycloalkyl group (preferably having a
carbon number of 4 to 20), a branched alkenyl group (preferably
having a carbon number of 4 to 20), a cycloalkenyl group
(preferably having a carbon number of 4 to 20) or an aryl group
(preferably having a carbon number of 4 to 20), more preferably a
copolymerization resin of the repeating unit (b) and the repeating
unit (c),
[0499] (D-5) a resin containing (a) a repeating unit having a
fluoroalkyl group (preferably having a carbon number of 1 to 4) and
(b) a repeating unit having a trialkylsilyl group or a cyclic
siloxane structure, more preferably a copolymerization resin of the
repeating unit (a) and the repeating unit (b), and
[0500] (D-6) a resin containing (a) a repeating unit having a
fluoroalkyl group (preferably having a carbon number of 1 to 4),
(b) a repeating unit having a trialkylsilyl group or a cyclic
siloxane structure, and (c) a repeating unit having a branched
alkyl group (preferably having a carbon number of 4 to 20), a
cycloalkyl group (preferably having a carbon number of 4 to 20), a
branched alkenyl group (preferably having a carbon number of 4 to
20), a cycloalkenyl group (preferably having a carbon number of 4
to 20) or an aryl group (preferably having a carbon number of 4 to
20), more preferably a copolymerization resin of the repeating unit
(a), the repeating unit (b) and the repeating unit (c).
[0501] As for the repeating unit (c) having a branched alkyl group,
a cycloalkyl group, a branched alkenyl group, a cycloalkenyl group
or an aryl group in the resins (D-3), (D-4) and (D-6), an
appropriate functional group can be introduced considering the
hydrophilicity/hydrophobicity, interaction and the like, but in
view of followability of immersion liquid or receding contact
angle, a functional group having no polar group is preferred.
[0502] In the resins (D-3), (D-4) and (D-6), the content of the
repeating unit (a) having a fluoroalkyl group and/or the repeating
unit (b) having a trialkylsilyl group or a cyclic siloxane
structure is preferably from 20 to 99 mol %.
[0503] Incidentally, the receding contact angle is a contact angle
measured when a contact line recedes on the liquid
droplet-substrate interface, and is generally known to be useful in
simulating the mobility of a liquid droplet in the dynamic state.
In a simple manner, the receding contact angle can be defined as a
contact angle created by the liquid droplet interface on receding
when a liquid droplet ejected from a needle tip is landed on a
substrate and then the liquid droplet is again sucked into the
needle. The receding contact angle can be generally measured by a
contact angle measuring method called an expansion/contraction
method.
[0504] In the immersion exposure step, the immersion liquid needs
to move on a wafer following the movement of an exposure head when
scanning the wafer at a high speed and forming an exposure pattern.
Therefore, the contact angle of the immersion liquid in a dynamic
state with the resist film is important and the resist is required
to have a performance of allowing a liquid droplet to follow the
high-speed scanning of an exposure head without remaining.
[0505] The resin (D) is preferably a resin having a repeating unit
represented by the following formula (Ia):
##STR00069##
[0506] In formula (Ia), Rf represents a fluorine atom or an alkyl
group with at least one hydrogen atom being substituted by a
fluorine atom.
[0507] R.sub.1 represents an alkyl group.
[0508] R.sub.2 represents a hydrogen atom or an alkyl group.
[0509] In formula (Ia), the alkyl group with at least one hydrogen
atom being substituted by a fluorine atom of Rf is preferably an
alkyl group having a carbon number of 1 to 3, more preferably a
trifluoromethyl group.
[0510] The alkyl group of R.sub.1 is preferably a linear or
branched alkyl group having a carbon number of 3 to 10, more
preferably a branched alkyl group having a carbon number of 3 to
10.
[0511] R.sub.2 is preferably a linear or branched alkyl group
having a carbon number of 1 to 10, more preferably a linear or
branched alkyl group having a carbon number of 3 to 10.
[0512] Specific examples of the repeating unit represented by
formula (Ia) are set forth below, but the present invention is not
limited thereto.
X.dbd.F or CF.sub.3
##STR00070## ##STR00071##
[0514] The repeating unit represented by formula (Ia) can be formed
by polymerizing a compound represented by the following formula
(I):
##STR00072##
[0515] In formula (I), Rf represents a fluorine atom or an alkyl
group with at least one hydrogen atom being substituted by a
fluorine atom.
[0516] R.sub.1 represents an alkyl group.
[0517] R.sub.2 represents a hydrogen atom or an alkyl group.
[0518] R.sub.f, R.sub.1 and R.sub.2 in formula (I) have the same
meanings as R.sub.f, R.sub.1 and R.sub.2 in formula (Ia).
[0519] The compound represented by formula (I) is a novel
compound.
[0520] As for the compound represented by formula (I), a
commercially available product or a compound synthesized may be
used. In the case of synthesizing the compound, this can be
attained by converting a 2-trifluoromethyl methacrylic acid into an
acid chloride and then esterifying the acid chloride.
[0521] The resin (D) containing a repeating unit represented by
formula (Ia) preferably further contains a repeating unit
represented by the following formula (III):
##STR00073##
[0522] In formula (III), R.sub.4 represents an alkyl group, a
cycloalkyl group, an alkenyl group, a cycloalkenyl group, a
trialkylsilyl group or a group having a cyclic siloxane
structure.
[0523] L.sub.6 represents a single bond or a divalent linking
group.
[0524] In formula (III), the alkyl group of R.sub.4 is preferably a
linear or branched alkyl group having a carbon number of 3 to
20.
[0525] The cycloalkyl group is preferably a cycloalkyl group having
a carbon number of 3 to 20.
[0526] The alkenyl group is preferably an alkenyl group having a
carbon number of 3 to 20.
[0527] The cycloalkenyl group is preferably a cycloalkenyl group
having a carbon number of 3 to 20.
[0528] The trialkylsilyl group is preferably a trialkylsilyl group
having a carbon number of 3 to 20.
[0529] The group having a cyclic siloxane structure is preferably a
group containing a cyclic siloxane structure having a carbon number
of 3 to 20.
[0530] The divalent linking group of L.sub.6 is preferably an
alkylene group (preferably having a carbon number of 1 to 5) or an
oxy group.
[0531] Specific examples of the resin (D) having a repeating unit
represented by formula (Ia) are set forth below, but the present
invention is not limited thereto.
##STR00074## ##STR00075## ##STR00076## ##STR00077##
##STR00078##
[0532] The resin (D) is preferably a resin containing a repeating
unit represented by the following formula (II) and a repeating unit
represented by the following formula (III):
##STR00079##
[0533] In formulae (II) and (III), Rf represents a fluorine atom or
an alkyl group with at least one hydrogen atom being substituted by
a fluorine atom.
[0534] R.sub.3 represents an alkyl group, a cycloalkyl group, an
alkenyl group, a cycloalkenyl group, or a group formed after two or
more members thereof are combined.
[0535] R.sub.4 represents an alkyl group, a cycloalkyl group, an
alkenyl group, a cycloalkenyl group, a trialkylsilyl group, a group
having a cyclic siloxane structure, or a group formed after two or
more members thereof are combined.
[0536] In the alkyl group, cycloalkyl group, alkenyl group,
cycloalkenyl group and trialkylsilyl group of R.sub.3 and R.sub.4,
a functional group can be introduced but in view of followability
of immersion liquid, a functional group not having a polar group is
preferred, and an unsubstituted functional group is more
preferred.
[0537] L.sub.6 represents a single bond or a divalent linking
group.
[0538] 0<m<100.
[0539] 0<n<100.
[0540] In formula (II), Rf has the same meaning as Rf in formula
(Ia).
[0541] The alkyl group of R.sub.3 is preferably a linear or
branched alkyl group having a carbon number of 3 to 20.
[0542] The cycloalkyl group is preferably a cycloalkyl group having
a carbon number of 3 to 20.
[0543] The alkenyl group is preferably an alkenyl group having a
carbon number of 3 to 20.
[0544] The cycloalkenyl group is preferably a cycloalkenyl group
having a carbon number of 3 to 20.
[0545] L.sub.6 is preferably a single bond, a methylene group, an
ethylene group or an ether group.
[0546] m=30 to 70 and n=30 to 70 are preferred, and m=40 to 60 and
n=40 to 60 are more preferred.
[0547] Specific examples of the resin (D) containing a repeating
unit represented by formula (11) and a repeating unit represented
by formula (III) are set forth below, but the present invention is
not limited thereto.
##STR00080## ##STR00081## ##STR00082## ##STR00083##
[0548] The resin (D) may contain a repeating unit represented by
the following formula (VIII):
##STR00084##
[0549] In formula (VIII), Z.sub.2 represents --O-- or
--N(R.sub.41)--. R.sub.41 represents a hydrogen atom, an alkyl
group or --OSO.sub.2--R.sub.42. R.sub.42 represents an alkyl group,
a cycloalkyl group or a camphor residue. The alkyl group of
R.sub.41 and R.sub.42 may be substituted by a halogen atom
(preferably fluorine atom) or the like.
[0550] The resin (D) is preferably solid at ordinary temperature
(25.degree. C.). Furthermore, the glass transition temperature (Tg)
is preferably from 50 to 200.degree. C., more preferably from 80 to
160.degree. C.
[0551] When the resin is solid at 25.degree. C., this means that
the melting point is 25.degree. C. or more.
[0552] The glass transition temperature (Tg) can be measured by a
scanning calorimeter (Differential Scanning Calorimeter). For
example, after once elevating the temperature of the sample and
then cooling it, the value by which the specific volume is changed
when the temperature of the sample is again elevated at 5.degree.
C./min is analyzed, whereby the glass transition temperature can be
measured.
[0553] The resin (D) is preferably stable to an acid and insoluble
in an alkali developer.
[0554] In view of followability of immersion liquid, the resin (D)
preferably contains none of (x) an alkali-soluble group, (y) a
group which decomposes under the action of an alkali (alkali
developer) to increase the solubility in an alkali developer, and
(z) a group which decomposes under the action of an acid to
increase the solubility in a developer.
[0555] In the resin (D), the total amount of repeating units having
an alkali-soluble group or a group of which solubility in a
developer increases under the action of an acid or alkali is
preferably 20 mol % or less, more preferably from 0 to 10 mol %,
still more preferably from 0 to 5 mol %, based on all repeating
units constituting the resin (D).
[0556] Also, unlike a surfactant generally used for resists, the
resin (D) does not have an ionic bond or a hydrophilic group such
as (poly(oxyalkylene)) group. If the resin (D) contains a
hydrophilic polar group, followability of immersion water tends to
decrease. Therefore, it is more preferred to not contain a polar
group selected from a hydroxyl group, alkylene glycols and a
sulfone group. Furthermore, an ether group bonded to the carbon
atom of the main chain through a linking group is preferably not
contained because the hydrophilicity increases and the
followability of immersion liquid deteriorates. On the other hand,
an ether group bonded directly to the carbon atom of the main chain
as in formula (III) sometimes express activity as a hydrophobic
group and is preferred.
[0557] Examples of the alkali-soluble group (x) include groups
having a phenolic hydroxyl group, a carboxylic acid group, a
fluorinated alcohol group, a sulfonic acid group, a sulfonamide
group, a sulfonylimide group, an
(alkylsulfonyl)(alkylcarbonyl)methylene group, an
(alkylsulfonyl)(alkylcarbonyl)imide group, a
bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group,
a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)-imide
group, a tris(alkylcarbonyl)methylene group or a
tris(alkylsulfonyl)methylene group.
[0558] Examples of the group (y) which decomposes under the action
of an alkali (alkali developer) to increase the solubility in an
alkali developer include a lactone group, an ester group, a
sulfonamide group, an acid anhydride and an acid imide group.
[0559] Examples of the group (z) which decomposes under the action
of an acid to increase the solubility in a developer include the
same groups as those of the acid-decomposable group in the
acid-decomposable resin (A).
[0560] However, the repeating unit represented by the following
formula (pA-C) is not or scarcely decomposed under the action of an
acid as compared with the acid-decomposable group of the resin (A)
and is regarded as substantially non-acid-decomposable.
##STR00085##
[0561] In formula (pA-c), Rp.sub.2 represents a hydrocarbon group
having a tertiary carbon atom bonded to the oxygen atom in the
formula.
[0562] In the case where the resin (D) contains a silicon atom, the
silicon atom content is preferably from 2 to 50 mass %, more
preferably from 2 to 30 mass %, based on the molecular weight of
the resin (D). Also, the silicon atom-containing repeating unit
preferably occupies from 10 to 100 mass %, more preferably from 20
to 100 mass %, in the resin (D).
[0563] In the case where the resin (D) contains a fluorine atom,
the fluorine atom content is preferably from 5 to 80 mass %, more
preferably from 10 to 80 mass %, based on the molecular weight of
the resin (D). Also, the fluorine atom-containing repeating unit
preferably occupies from 10 to 100 mass %, more preferably from 30
to 100 mass %, in the resin (D).
[0564] The standard polystyrene-reduced weight average molecular of
the resin (D) is preferably from 1,000 to 100,000, more preferably
from 1,000 to 50,000, still more preferably from 2,000 to 15,000,
yet still more preferably from 3,000 to 15,000.
[0565] The residual monomer amount in the resin (D) is preferably
from 0 to 10 mass %, more preferably from 0 to 5 mass %, still more
preferably from 0 to 1 mass %. Also, in view of the resolution,
resist profile, and side wall, roughness or the like of the resist
pattern, the molecular weight distribution (Mw/Mn, also called
dispersity) is preferably from 1 to 5, more preferably from 1 to 3,
still more preferably from 1 to 1.5.
[0566] The amount added of the resin (D) in the positive resist
composition is preferably from 0.1 to 20 mass %, more preferably
from 0.1 to 10 mass %, still more preferably from 0.1 to 5 mass %,
still even more preferably from 0.2 to 3.0 mass %, yet still even
more preferably from 0.3 to 2.0 mass %, based on the entire solid
content of the resist composition.
[0567] Similarly to the acid-decomposable resin (A), it is
preferred that, as a matter of course, the resin (D) has less
impurities such as metal and also, the content of the residual
monomer or oligomer component is not more than a specific value,
for example, 0.1 mass % by HPLC. When these conditions are
satisfied, not only the resist can be improved in the sensitivity,
resolution, process stability, pattern profile and the like but
also a resist free from foreign matters in liquid or change in the
sensitivity and the like with the lapse of time can be
obtained.
[0568] As for the resin (D), various commercially available
products may be used or the resin may be synthesize by an ordinary
method (for example, radical polymerization)). Examples of the
synthesis method in general include a batch polymerization method
of dissolving monomer species and an initiator in a solvent and
heating the solution, thereby effecting the polymerization, and a
dropping polymerization method of adding dropwise a solution
containing monomer species and an initiator to a heated solvent
over 1 to 10 hours. A dropping polymerization method is preferred.
Examples of the reaction solvent include tetrahydrofuran,
1,4-dioxane, ethers such as diisopropyl ether, ketones such as
methyl ethyl ketone and methyl isobutyl ketone, an ester solvent
such as ethyl acetate, an amide solvent such as dimethylformamide
and dimethylacetamide, and a solvent capable of dissolving the
composition of the present invention, which is described later,
such as propylene glycol monomethyl ether acetate, propylene glycol
monomethyl ether and cyclohexanone. The polymerization is more
preferably performed using the same solvent as the solvent used in
the resist composition of the present invention. By the use of this
solvent, generation of particles during storage can be
suppressed.
[0569] The polymerization reaction is preferably performed in an
inert gas atmosphere such as nitrogen and argon. As for the
polymerization initiator, the polymerization is started using a
commercially available radical initiator (e.g., azo-based
initiator, peroxide). The radical initiator is preferably an
azo-based initiator, and an azo-based initiator having an ester
group, a cyano group or a carboxyl group is preferred. Preferred
examples of the initiator include azobisisobutyronitrile,
azobisdimethylvaleronitrile and dimethyl
2,2'-azobis(2-methyl-propionate). A chain transfer agent may also
be used, if desired. The reaction concentration is usually from 5
to 50 mass %, preferably from 20 to 50 mass %, more preferably from
30 to 50 mass %, and the reaction temperature is usually from 10 to
150.degree. C., preferably from 30 to 120.degree. C., more
preferably from 60 to 100.degree. C.
[0570] After the completion of reaction, the reactant is allowed to
cool to room temperature and purified. The purification may be
performed by a normal method, for example, a liquid-liquid
extraction method of applying water washing or combining an
appropriate solvent to remove residual monomers or oligomer
components; a purification method in a solution sate, such as
ultrafiltration of removing by extraction only polymers having a
molecular weight lower than a specific molecular weight; a
reprecipitation method of adding dropwise the resin solution in a
bad solvent to solidify the resin in the bad solvent and thereby
remove residual monomers or the like; and a purification method in
a solid state, such as washing of the resin slurry with a bad
solvent after separation by filtration. For example, the resin is
precipitated as a solid through contact with a solvent in which the
resin is sparingly soluble or insoluble (bad solvent) and which is
in a volume amount of 10 times or less, preferably from 10 to 5
times, the reaction solution.
[0571] The solvent used at the operation of precipitation or
reprecipitation from the polymer solution (precipitation or
reprecipitation solvent) may be sufficient if it is a bad solvent
to the polymer, and the solvent used may be appropriately selected
according to the kind of the polymer from, for example, a
hydrocarbon (e.g., an aliphatic hydrocarbon such as pentane,
hexane, heptane and octane; an alicyclic hydrocarbon such as
cyclohexane and methyl-cyclohexane; an aromatic hydrocarbon such as
benzene, toluene and xylene), a halogenated hydrocarbon (e.g., a
halogenated aliphatic hydrocarbon such as methylene chloride,
chloroform and carbon tetrachloride; a halogenated aromatic
hydrocarbon such as chlorobenzene and dichlorobenzene), a nitro
compound (e.g., nitromethane, nitroethane), a nitrile (e.g.,
acetonitrile, benzonitrile), an ether (e.g., a chain ether such as
diethyl ether, diisopropyl ether and dimethoxyethane; a cyclic
ether such as tetrahydrofuran and dioxane), a ketone (e.g.,
acetone, methyl ethyl ketone, diisobutyl ketone), an ester (e.g.,
ethyl acetate, butyl acetate), a carbonate (e.g., dimethyl
carbonate, diethyl carbonate, ethylene carbonate, propylene
carbonate), an alcohol (e.g., methanol, ethanol, propanol,
isopropyl alcohol, butanol), a carboxylic acid (e.g., acetic acid),
water, and a mixed solvent containing such a solvent. Among these,
the precipitation or reprecipitation solvent is preferably a
solvent containing at least an alcohol (particularly methanol or
the like) or water. In such a solvent containing at least a
hydrocarbon, the ratio of the alcohol (particularly methanol or the
like) to other solvents (for example, an ester such as ethyl
acetate, and ethers such as tetrahydrofuran) is approximately, for
example, the former/the latter (volume ratio, at 25.degree.
C.)=from 10/90 to 99/1, preferably the former/the latter (volume
ratio, at 25.degree. C.)=from 30/70 to 98/2, more preferably the
former/the latter (volume ratio, at 25.degree. C.)=from 50/50 to
97/3.
[0572] The amount of the precipitation or reprecipitation solvent
used may be appropriately selected by taking into account the
efficiency, yield and the like, but in general, the amount used is
from 100 to 10,000 parts by mass, preferably from 200 to 2,000
parts by mass, more preferably from 300 to 1,000 parts by mass, per
100 parts by mass of the polymer solution.
[0573] The nozzle bore diameter at the time of feeding the polymer
solution into a precipitation or reprecipitation solvent (bad
solvent) is preferably 4 mm.phi. or less (for example, from 0.2 to
4 mm.phi.), and the feeding rate (dropping rate) of the polymer
solution into the bad solvent is, for example, in terms of the
linear velocity, from 0.1 to 10 m/sec, preferably from 0.3 to 5
m/sec.
[0574] The precipitation or reprecipitation operation is preferably
performed under stirring. Examples of the stirring blade which can
be used for the stirring include a disc turbine, a fan turbine
(including paddle), a curved vane turbine, a feathering turbine, a
Pfaudler type, a bull margin type, an angled vane fan turbine, a
propeller, a multistage type, an anchor type (or horseshoe type), a
gate type, a double ribbon type and a screw type. The stirring is
preferably further performed for 10 minutes or more, more
preferably 20 minutes or more, after the completion of feeding of
the polymer solution. If the stirring time is short, the monomer
content in the polymer particle may not be sufficiently reduced.
The mixing and stirring of the polymer solution and the bad solvent
may also be performed using a line mixer instead of the stirring
blade.
[0575] The temperature at the precipitation or reprecipitation may
be appropriately selected by taking into account the efficiency or
operability, but the temperature is usually on the order of 0 to
50.degree. C., preferably in the vicinity of room temperature (for
example, approximately from 20 to 35.degree. C.). The precipitation
or reprecipitation operation may be performed using a commonly
employed mixing vessel such as stirring tank according to a known
method such as batch system and continuous system.
[0576] The precipitated or reprecipitated particulate polymer is
usually subjected to commonly employed solid-liquid separation such
as filtration and centrifugation, then dried and used. The
filtration is performed using a solvent-resistant filter element
preferably under pressure. The drying is performed under
atmospheric pressure or reduced pressure (preferably under reduced
pressure) at a temperature of approximately from 30 to 100.degree.
C., preferably on the order of 30 to 50.degree. C.
[0577] Incidentally, after the resin is once precipitated and
separated, the resin may be again dissolved in a solvent and then
put into contact with a solvent in which the resin is sparingly
soluble or insoluble.
[0578] More specifically, there may be used a method comprising,
after the completion of radical polymerization reaction,
precipitating a resin by bringing the polymer into contact with a
solvent in which the polymer is sparingly soluble or insoluble
(step a), separating the resin from the solution (step b), anew
dissolving the resin in a solvent to prepare a resin solution A
(step c), precipitating a resin solid by bringing the resin
solution A into contact with a solvent in which the resin is
sparingly soluble or insoluble and which is in a volume amount of
less than 10 times (preferably a volume amount of 5 times or less)
the resin solution A (step d), and separating the precipitated
resin (step e).
[0579] As for the solvent used at the preparation of the resin
solution A, the same solvent as the solvent for dissolving the
monomer at the polymerization reaction may be used, and the solvent
may be the same as or different from the solvent used at the
polymerization reaction.
(E) Basic Compound
[0580] The positive resist composition of the present invention
preferably comprises (E) a basic compound for reducing the change
of performance in aging from exposure until heating.
[0581] Preferred examples of the basic compound include compounds
having a structure represented by any one of the following formulae
(A) to (E):
##STR00086##
[0582] In formulae (A) to (E), R.sup.200, R.sup.201 and R.sup.202,
which may be the same or different, each represents a hydrogen
atom, an alkyl group (preferably having a carbon number of 1 to
20), a cycloalkyl group (preferably having a carbon number of 3 to
20) or an aryl group (having a carbon number of 6 to 20), and
R.sup.201 and R.sup.202 may combine with each other to form a
ring.
[0583] As for the alkyl group, the alkyl group having a substituent
is preferably an aminoalkyl group having a carbon number of 1 to
20, a hydroxyalkyl group having a carbon number of 1 to 20, or a
cyanoalkyl group having a carbon number of 1 to 20.
[0584] R.sup.203, R.sup.204, R.sup.205 and R.sup.206, which may be
the same or different, each represents an alkyl group having a
carbon number of 1 to 20.
[0585] The alkyl group in these formulae (A) to (E) is more
preferably unsubstituted.
[0586] Preferred examples of the compound include guanidine,
aminopyrrolidine, pyrazole, pyrazoline, piperazine,
aminomorpholine, aminoalkylmorpholine and piperidine. More
preferred examples of the compound include a compound having an
imidazole structure, a diazabicyclo structure, an onium hydroxide
structure, an onium carboxylate structure, a trialkylamine
structure, an aniline structure or a pyridine structure; an
alkylamine derivative having a hydroxyl group and/or an ether bond;
and an aniline derivative having a hydroxyl group and/or an ether
bond.
[0587] Examples of the compound having an imidazole structure
include imidazole, 2,4,5-triphenylimidazole and benzimidazole.
Examples of the compound having a diazabicyclo structure include
1,4-diazabicyclo[2,2,2]octane, 1,5-diazabicyclo[4,3,0]non-5-ene and
1,8-diazabicyclo[5,4,0]undec-7-ene. Examples of the compound having
an onium hydroxide structure include triarylsulfonium hydroxide,
phenacylsulfonium hydroxide and sulfonium hydroxide having a
2-oxoalkyl group, specifically, triphenylsulfonium hydroxide,
tris(tert-butylphenyl)sulfonium hydroxide,
bis(tert-butylphenyl)iodonium hydroxide, phenacylthiophenium
hydroxide and 2-oxopropylthiophenium hydroxide. Examples of the
compound having an onium carboxylate structure include a compound
where the anion moiety of the compound having an onium hydroxide
structure is converted into a carboxylate, such as acetate,
adamantane-1-carboxylate and perfluoroalkyl carboxylate. Examples
of the compound having a trialkylamine structure include
tri(n-butyl)amine and tri(n-octyl)amine. Examples of the aniline
compound include 2,6-diisopropylaniline, N,N-dimethylaniline,
N,N-dibutylaniline and N,N-dihexylaniline. Examples of the
alkylamine derivative having a hydroxyl group and/or an ether bond
include ethanolamine, diethanolamine, triethanolamine and
tris(methoxyethoxyethyl)amine. Examples of the aniline derivative
having a hydroxyl group and/or an ether bond include
N,N-bis(hydroxyethyl)aniline.
[0588] Other examples include an amine compound having a phenoxy
group, and an ammonium salt compound having a phenoxy group.
[0589] As for the amine compound, a primary, secondary or tertiary
amine compound can be used, and an amine compound where at least
one alkyl group is bonded to the nitrogen atom is preferred. The
amine compound is preferably a tertiary amine compound. In the
amine compound, as long as at least one alkyl group (preferably
having a carbon number of 1 to 20) is bonded to the nitrogen atom,
a cycloalkyl group (preferably having a carbon number of 3 to 20)
or an aryl group (preferably having a carbon number of 6 to 12) may
be bonded to the nitrogen atom in addition to the alkyl group.
[0590] The amine compound preferably has an oxygen atom in the
alkyl chain to form an oxyalkylene group. The number of oxyalkylene
groups within the molecule is 1 or more, preferably from 3 to 9,
more preferably from 4 to 6. Among oxyalkylene groups, an
oxyethylene group (--CH.sub.2CH.sub.2O--) and an oxypropylene group
(--CH(CH.sub.3)CH.sub.2O-- or --CH.sub.2CH.sub.2CH.sub.2O--) are
preferred, and an oxyethylene group is more preferred.
[0591] As for the ammonium salt compound, a primary, secondary,
tertiary or quaternary ammonium salt compound can be used, and an
ammonium salt compound where at least one alkyl group is bonded to
the nitrogen atom is preferred. In the ammonium salt compound, as
long as at least one alkyl group (preferably having a carbon number
of 1 to 20) is bonded to the nitrogen atom, a cycloalkyl group
(preferably having a carbon number of 3 to 20) or an aryl group
(preferably having a carbon number of 6 to 12) may be bonded to the
nitrogen atom in addition to the alkyl group.
[0592] The ammonium salt compound preferably has an oxygen atom in
the alkyl chain to form an oxyalkylene group. The number of
oxyalkylene groups within the molecule is 1 or more, preferably
from 3 to 9, more preferably from 4 to 6. Among oxyalkylene groups,
an oxyethylene group (--CH.sub.2CH.sub.2O--) and an oxypropylene
group (--CH(CH.sub.3)CH.sub.2O-- or --CH.sub.2CH.sub.2CH.sub.2O--)
are preferred, and an oxyethylene group is more preferred.
[0593] Examples of the anion of the ammonium salt compound include
a halogen atom, a sulfonate, a borate and a phosphate, with a
halogen atom and a sulfonate being preferred. The halogen atom is
preferably chloride, bromide or iodide, and the sulfonate is
preferably an organic sulfonate having a carbon number of 1 to 20.
Examples of the organic sulfonate include an alkyl sulfonate having
a carbon number of 1 to 20 and an aryl sulfonate. The alkyl group
of the alkyl sulfonate may have a substituent, and examples of the
substituent include fluorine, chlorine, bromine, an alkoxy group,
an acyl group and an aryl group.
[0594] Specific examples of the alkyl sulfonate include
methanesulfonate, ethanesulfonate, butanesulfonate,
hexanesulfonate, octanesulfonate, benzylsulfonate,
trifluoromethanesulfonate, pentafluoroethanesulfonate and
nonafluorobutanesulfonate. The aryl group of the aryl sulfonate
includes a benzene ring, a naphthalene ring and an anthracene ring.
The benzene ring, naphthalene ring and anthracene ring may have a
substituent and as for the substituent, a linear or branched alkyl
group having a carbon number of 1 to 6 and a cycloalkyl group
having a carbon number of 3 to 6 are preferred. Specific examples
of the linear or branched alkyl group and the cycloalkyl group
include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl,
tert-butyl, n-hexyl and cyclohexyl. Other examples of the
substituent include an alkoxy group having a carbon number of 1 to
6, a halogen atom, cyano, nitro, an acyl group and an acyloxy
group.
[0595] The amine compound having a phenoxy group and the ammonium
salt compound having a phenoxy group are a compound where the alkyl
group of an amine compound or ammonium salt compound has a phenoxy
group at the terminal opposite the nitrogen atom. The phenoxy group
may have a substituent. Examples of the substituent of the phenoxy
group include an alkyl group, an alkoxy group, a halogen atom, a
cyano group, a nitro group, a carboxyl group, a carboxylic acid
ester group, a sulfonic acid ester group, an aryl group, an aralkyl
group, an acyloxy group and an aryloxy group. The substitution
position of the substituent may be any of 2- to 6-positions, and
the number of substituents may be any in the range from 1 to 5.
[0596] The compound preferably has at least one oxyalkylene group
between the phenoxy group and the nitrogen atom. The number of
oxyalkylene groups within the molecule is 1 or more, preferably
from 3 to 9, more preferably from 4 to 6. Among oxyalkylene groups,
an oxyethylene group (--CH.sub.2CH.sub.2O--) and an oxypropylene
group (--CH(CH.sub.3)CH.sub.2O-- or --CH.sub.2CH.sub.2CH.sub.2O--)
are preferred, and an oxyethylene group is more preferred.
[0597] The amine compound having a phenoxy group can be obtained by
reacting a primary or secondary amine having a phenoxy group with a
haloalkyl ether under heating, adding an aqueous solution of strong
base such as sodium hydroxide, potassium hydroxide and
tetraalkylammonium, and performing extraction with an organic
solvent such as ethyl acetate and chloroform, or by reacting a
primary or secondary amine with a haloalkyl ether having a phenoxy
group at the terminal under heating, adding an aqueous solution of
strong base such as sodium hydroxide, potassium hydroxide and
tetraalkylammonium, and performing extraction with an organic
solvent such as ethyl acetate and chloroform.
[0598] One of these basic compounds is used alone, or two or more
species thereof are used in combination.
[0599] The amount of the basic compound used is usually from 0.001
to 10 mass %, preferably from 0.01 to 5 mass %, based on the solid
content of the positive resist composition.
[0600] The ratio of the acid generator and the basic compound used
in the composition is preferably acid generator/basic compound (by
mol)=from 2.5 to 300. That is, the molar ratio is preferably 2.5 or
more in view of sensitivity and resolution and preferably 300 or
less from the standpoint of suppressing the reduction in resolution
due to thickening of the resist pattern in aging after exposure
until heat treatment. The acid generator/basic compound (by mol) is
more preferably from 5.0 to 200, still more preferably from 7.0 to
150.
(F) Surfactant
[0601] The positive resist composition of the present invention
preferably further comprises (F) a surfactant, more preferably any
one fluorine-containing and/or silicon-containing surfactant (a
fluorine-containing surfactant, a silicon-containing surfactant or
a surfactant containing both a fluorine atom and a silicon atom) or
two or more species thereof.
[0602] When the positive resist composition of the present
invention contains the surfactant (F), a resist pattern with good
sensitivity, resolution and adhesion as well as less development
defects can be obtained when an exposure light source of 250 nm or
less, particularly 220 nm or less, is used.
[0603] Examples of the fluorine-containing and/or
silicon-containing surfactant include surfactants described in
JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950,
JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432,
JP-A-9-5988, JP-A-2002-277862 and U.S. Pat. Nos. 5,405,720,
5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511
and 5,824,451. The following commercially available surfactants
each may also be used as it is.
[0604] Examples of the commercially available surfactant which can
be used include a fluorine-containing surfactant and a
silicon-containing surfactant, such as EFtop EF301 and EF303
(produced by Shin-Akita Kasei K.K.); Florad FC430, 431 and 4430
(produced by Sumitomo 3M Inc.); Megafac F171, F173, F176, F189,
F113, F110, F177, F120 and R08 (produced by Dainippon Ink &
Chemicals, Inc.); Surflon S-382, SC101, 102, 103, 104, 105 and 106
(produced by Asahi Glass Co., Ltd.); Troysol S-366 (produced by
Troy Chemical); GF-300 and GF-150 (produced by Toagosei Chemical
Industry Co., Ltd.); Surftlon S-393 (produced by Seimi Chemical
Co., Ltd.); Eftop EF121, EF122A, EF122B, RF122C, EF125M, EF135M,
EF351, 352, EF801, EF802 and EF601 (produced by JEMCO Inc.); PF636,
PF656, PF6320 and PF6520 (produced by OMNOVA); and FTX-204D, 208G,
218G, 230G, 204D, 208D, 212D, 218 and 222D (produced by NEOS Co.,
Ltd.). In addition, polysiloxane polymer KP-341 (produced by
Shin-Etsu Chemical Co., Ltd.) may also be used as the
silicon-containing surfactant.
[0605] Other than those known surfactants, a surfactant using a
polymer having a fluoro-aliphatic group derived from a
fluoro-aliphatic compound which is produced by a telomerization
process (also called a telomer process) or an oligomerization
process (also called an oligomer process), may be used. The
fluoro-aliphatic compound can be synthesized by the method
described in JP-A-2002-90991.
[0606] The polymer having a fluoro-aliphatic group is preferably a
copolymer of a fluoro-aliphatic group-containing monomer with a
(poly(oxyalkylene)) acrylate and/or a (poly(oxyalkylene))
methacrylate, and the polymer may have an irregular distribution or
may be a block copolymer. Examples of the poly(oxyalkylene) group
include a poly(oxyethylene) group, a poly(oxypropylene) group and a
poly(oxybutylene) group. This group may also be a unit having
alkylenes differing in the chain length within the same chain, such
as block-linked poly(oxyethylene, oxypropylene and oxyethylene) and
block-linked poly(oxyethylene and oxypropylene). Furthermore, the
copolymer of a fluoro-aliphatic group-containing monomer and a
(poly(oxyalkylene)) acrylate (or methacrylate) is not limited only
to a binary copolymer but may also be a ternary or greater
copolymer obtained by simultaneously copolymerizing two or more
different fluoro-aliphatic group-containing monomers or two or more
different (poly(oxyalkylene)) acrylates (or methacrylates).
[0607] Examples thereof include, as the commercially available
surfactant, Megafac F178, F-470, F-473, F-475, F-476 and F-472
(produced by Dainippon Ink & Chemicals, Inc.) and further
include a copolymer of a C.sub.6F.sub.13 group-containing acrylate
(or methacrylate) with a (poly(oxyalkylene)) acrylate (or
methacrylate), and a copolymer of a C.sub.3F.sub.7 group-containing
acrylate (or methacrylate) with a (poly(oxyethylene)) acrylate (or
methacrylate) and a (poly(oxypropylene)) acrylate (or
methacrylate).
[0608] In the present invention, a surfactant other than the
fluorine-containing and/or silicon-containing surfactant may also
be used. Specific examples thereof include a nonionic surfactant
such as polyoxyethylene alkyl ethers (e.g., polyoxyethylene lauryl
ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether,
polyoxyethylene oleyl ether), polyoxyethylene alkylallyl ethers
(e.g., polyoxyethylene octylphenol ether, polyoxyethylene
nonylphenol ether), polyoxyethylene.polyoxypropylene block
copolymers, sorbitan fatty acid esters (e.g., sorbitan monolaurate,
sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate,
sorbitan trioleate, sorbitan tristearate) and polyoxyethylene
sorbitan fatty acid esters (e.g., polyoxyethylene sorbitan
monolaurate, polyoxyethylene sorbitan monopalmitate,
polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan
trioleate, polyoxyethylene sorbitan tristearate).
[0609] One of these surfactants may be used alone, or several
species thereof may be used in combination.
[0610] The amount of the surfactant (F) used is preferably from
0.01 to 10 mass %, more preferably from 0.1 to 5 mass %, based on
the entire amount of the positive resist composition (excluding the
solvent).
(G) Onium Carboxylate
[0611] The positive resist composition of the present invention may
comprise (G) an onium carboxylate. Examples of the onium
carboxylate include sulfonium carboxylate, iodonium carboxylate and
ammonium carboxylate. In particular, the onium carboxylate (G) is
preferably an iodonium salt or a sulfonium salt. Furthermore, the
carboxylate residue of the onium carboxylate (H) for use in the
present invention preferably contains no aromatic group and no
carbon-carbon double bond. The anion moiety is preferably a linear,
branched, monocyclic or polycyclic alkylcarboxylate anion having a
carbon number of 1 to 30, more preferably an anion of the
carboxylic acid with the alkyl group being partially or entirely
fluorine-substituted. The alkyl chain may contain an oxygen atom.
By virtue of such a construction, the transparency to light of 220
nm or less is ensured, the sensitivity and resolution are enhanced,
and the defocus latitude depended on line pitch and the exposure
margin are improved.
[0612] Examples of the anion of a fluorine-substituted carboxylic
acid include anions of fluoroacetic acid, difluoroacetic acid,
trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric
acid, nonafluoropentanoic acid, perfluorododecanoic acid,
perfluoro-tridecanoic acid, perfluorocyclohexanecarboxylic acid and
2,2-bistrifluoromethylpropionic acid.
[0613] These onium carboxylates (G) can be synthesized by reacting
a sulfonium, iodonium or ammonium hydroxide and a carboxylic acid
with silver oxide in an appropriate solvent.
[0614] The content of the onium carboxylate (G) in the composition
is generally from 0.1 to 20 mass %, preferably from 0.5 to 10 mass
%, more preferably from 1 to 7 mass %, based on the entire solid
content of the composition.
(H) Other Additives
[0615] The positive resist composition of the present invention may
further contain, for example, a dye, a plasticizer, a
photosensitizer, a light absorbent, an alkali-soluble resin, a
dissolution inhibitor and a compound for accelerating dissolution
in a developer (for example, a phenol compound having a molecular
weight of 1,000 or less, or a carboxyl group-containing alicyclic
or aliphatic compound), if desired.
[0616] The phenol compound having a molecular weight of 1,000 or
less can be easily synthesized by one skilled in the art with
reference to the methods described, for example, in JP-A-4-122938,
JP-A-2-28531, U.S. Pat. No. 4,916,210 and European Patent
219294.
[0617] Specific examples of the carboxyl group-containing alicyclic
or aliphatic compound include, but are not limited to, a carboxylic
acid derivative having a steroid structure, such as cholic acid,
deoxycholic acid and lithocholic acid, an adamantanecarboxylic acid
derivative, an adamantanedicarboxylic acid, a cyclohexanecarboxylic
acid and a cyclohexanedicarboxylic acid.
[0618] In the pattern forming method of the present invention, the
step of forming a film on a substrate by using a resin composition
of which solubility in a positive developer increases and
solubility in a negative developer decreases upon irradiation with
actinic rays or radiation, the step of exposing the film, the step
of heating (baking, also called PEB (post exposure bake)) the film,
and the step of effecting positive development of the film may be
performed by generally known methods.
[0619] The exposure device for use in the present invention is not
limited in the light source wavelength, but, for example, a KrF
excimer laser wavelength (248 nm), an ArF excimer laser wavelength
(193 nm), an F.sub.2 excimer laser wavelength (157 nm) and an EUV
light (13.5 nm) can be applied.
[0620] In the step of performing exposure of the present invention,
an immersion exposure method can be applied.
[0621] The immersion exposure method is a technique for enhancing
the resolving power, and according to this technique, exposure is
performed by filling a high refractive-index liquid (hereinafter
sometimes referred to as an "immersion liquid") between the
projection lens and the sample.
[0622] As for the "effect of immersion", assuming that NA.sub.0=sin
.theta., the resolving power and focal depth when immersed can be
expressed by the following formulae:
(Resolving power)=k.sub.1(.lamda..sub.0/n)/NA.sub.0
(Focal depth)=.+-.k.sub.2(.lamda..sub.0/n)/NA.sub.0.sup.2
wherein .lamda..sub.0 is the wavelength of exposure light in air, n
is the refractive index of the immersion liquid based on air, and
.theta. is the convergence half-angle of beam.
[0623] That is, the effect of immersion is equal to use of an
exposure wavelength of 1/n. In other words, when the projection
optical system has the same NA, the focal depth can be made n times
larger by the immersion. This is effective for all pattern profiles
and can be combined with super-resolution techniques under study at
present, such as phase-shift method and modified illumination
method.
[0624] In the case of performing immersion exposure, a step of
washing the film surface with an aqueous chemical solution may be
performed (1) after the film is formed on a substrate and exposed
and/or (2) after the step of exposing the film through an immersion
liquid but before the step of heating the film.
[0625] The immersion liquid is preferably a liquid transparent to
light at the exposure wavelength and having a small temperature
coefficient of refractive index as much as possible so as to
minimize the distortion of an optical image projected on the film.
Particularly, when the exposure light source is an ArF excimer
laser (wavelength: 193 nm), water is preferably used in view of
easy availability and easy handleability, in addition to the
above-described aspects.
[0626] In the case of using water, an additive (liquid) capable of
decreasing the surface tension of water and increasing the surface
activity may be added in a small ratio. This additive is preferably
an additive which does not dissolve the resist layer on a wafer and
at the same time, gives only a negligible effect on the optical
coat at the undersurface of the lens element.
[0627] Such an additive is preferably, for example, an aliphatic
alcohol having a refractive index nearly equal to that of water,
and specific examples thereof include methyl alcohol, ethyl alcohol
and isopropyl alcohol. By virtue of adding an alcohol having a
refractive index nearly equal to that of water, even when the
alcohol component in water is evaporated and its content
concentration is changed, the change in the refractive index of the
entire liquid can be advantageously made very small.
[0628] On the other hand, if a substance opaque to light at 193 nm
or an impurity greatly differing in the refractive index from water
is mingled, this incurs distortion of the optical image projected
on the resist. Therefore, the water used is preferably distilled
water. Pure water after further filtration through an ion exchange
filter or the like may also be used.
[0629] In the present invention, the substrate on which the film is
formed is not particularly limited, and an inorganic substrate such
as silicon, SiN, SiO.sub.2 and SiN, a coating-type inorganic
substrate such as SOG, or a substrate generally used in the process
of producing a semiconductor such as IC or producing a circuit
board of liquid crystal, thermal head or the like or in the
lithography process of other photo applications can be used. If
desired, an organic antireflection film may be formed between the
resist film and the substrate.
[0630] As for the organic antireflection film, organic films
comprising a light absorbent and a polymer material all can be
used. For example, a commercially available organic antireflection
film such as DUV-30 Series and DUV-40 Series produced by Brewer
Science, Inc., AR-2, AR-3 and AR-5 produced by Shipley Co., Ltd.,
and ARC Series (e.g., ARC29A) produced by Nissan Chemical
Industries, Ltd. may be used. Furthermore, an inorganic
antireflection film can also be used as the antireflection film.
For example, an antireflection film such as titanium, titanium
dioxide, titanium nitride, chromium oxide, carbon and amorphous
silicon may be used.
[0631] At the time of performing positive development, an alkali
developer is preferably used.
[0632] The alkali developer which can be used when performing
positive development is, for example, an alkaline aqueous solution
of inorganic alkalis such as sodium hydroxide, potassium hydroxide,
sodium carbonate, sodium silicate, sodium metasilicate and aqueous
ammonia, primary amines such as ethylamine and n-propylamine,
secondary amines such as diethylamine and di-n-butylamine, tertiary
amines such as triethylamine and methyldiethyl-amine, alcohol
amines such as dimethylethanolamine and triethanolamine, quaternary
ammonium salts such as tetramethylammonium hydroxide and
tetraethylammonium hydroxide, and cyclic amines such as pyrrole and
piperidine.
[0633] Furthermore, this alkaline aqueous solution may be used
after adding thereto alcohols and a surfactant each in an
appropriate amount.
[0634] The alkali concentration of the alkali developer is usually
from 0.1 to 20 mass %.
[0635] The pH of the alkali developer is usually from 10.0 to
15.0.
[0636] In particular, an aqueous 2.38% tetramethylammonium
hydroxide solution is preferred.
[0637] As for the rinsing solution in the rinsing treatment
performed after positive development, pure water is used, and the
pure water may be used after adding thereto a surfactant in an
appropriate amount.
[0638] At the time of performing negative development, an organic
developer containing an organic solvent is preferably used.
[0639] As for the organic developer which can be used when
performing negative development, a polar solvent such as
ketone-based solvent, ester-based solvent, alcohol-based solvent,
amide-based solvent and ether-based solvent, and a
hydrocarbon-based solvent can be used.
[0640] In the present invention, the ketone-based solvent indicates
a solvent having a ketone group within the molecule, the
ester-based solvent indicates a solvent having an ester group
within the molecule, the alcohol-based solvent indicates a solvent
having an alcoholic hydroxyl group within the molecule, the
amide-based solvent indicates a solvent having an amide group
within the molecule, and the ether-based solvent indicates a
solvent having an ether bond within the molecule. Some of these
solvents have a plurality of kinds of the functional groups
described above within one molecule and in this case, the solvent
comes under all solvent species corresponding to the functional
groups contained in the solvent. For example, diethylene glycol
monomethyl ether comes under both an alcohol-based solvent and an
ether-based solvent in the classification above. The
hydrocarbon-based solvent indicates a hydrocarbon solvent having no
substituent.
[0641] Examples of the ketone-based solvent include 1-octanone,
2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone,
1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone,
methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl
isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl
alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone,
isophorone, propylene carbonate and .gamma.-butyrolactone.
[0642] Examples of the ester-based solvent include methyl acetate,
butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate,
isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate,
propylene glycol monomethyl ether acetate, ethylene glycol
monoethyl ether acetate, ethylene glycol monopropyl ether acetate,
ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl
ether acetate, diethylene glycol monomethyl ether acetate,
diethylene glycol monopropyl ether acetate, diethylene glycol
monoethyl ether acetate, diethylene glycol monophenyl ether
acetate, diethylene glycol monobutyl ether acetate, diethylene
glycol monoethyl ether acetate, 2-methoxybutyl acetate,
3-methoxybutyl acetate, 4-methoxybutyl acetate,
3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate,
propylene glycol monomethyl ether acetate, propylene glycol
monoethyl ether acetate, propylene glycol monopropyl ether acetate,
2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl
acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate,
4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate,
3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate,
4-methyl-4-methoxypentyl acetate, propylene glycol diacetate,
methyl formate, ethyl formate, butyl formate, propyl formate, ethyl
lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl
carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl
pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate,
methyl propionate, ethyl propionate, propyl propionate, isopropyl
propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate,
methyl-3-methoxypropionate, ethyl-3-methoxypropionate,
ethyl-3-ethoxypropionate and propyl-3-methoxypropionate.
[0643] As for the ester-based solvent, a solvent represented by
formula (1) described later or a solvent represented by formula (2)
described later is preferred, a solvent represented by formula (1)
is more preferred, an alkyl acetate is still more preferred, and
butyl acetate is most preferred.
[0644] Examples of the alcohol-based solvent include an alcohol
such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl
alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol,
isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl
alcohol, n-decanol and 3-methoxy-1-butanol; a glycol-based solvent
such as ethylene glycol, diethylene glycol and triethylene glycol;
and a hydroxyl group-containing glycol ether-based solvent such as
ethylene glycol monomethyl ether, propylene glycol monomethyl
ether, ethylene glycol, diethylene glycol monomethyl ether,
triethylene glycol monoethyl ether, methoxymethyl butanol, ethylene
glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene
glycol monobutyl ether, propylene glycol monoethyl ether, propylene
glycol monopropyl ether, propylene glycol monobutyl ether and
propylene glycol monophenyl ether. Among these, a glycol
ether-based solvent is preferred.
[0645] Examples of the ether-based solvent include, in addition to
the hydroxyl group-containing glycol ether-based solvents above, a
hydroxyl group-free glycol ether-based solvent such as propylene
glycol dimethyl ether, propylene glycol diethyl ether, diethylene
glycol dimethyl ether and diethylene glycol diethyl ether; dioxane;
tetrahydrofuran; anisole; perfluoro-2-butyltetrahydrofuran; and
1,4-dioxane. A glycol ether-based solvent is preferably used.
[0646] Examples of the amide-based solvent which can be used
include N-methyl-2-pyrrolidone, N,N-dimethylacetamide,
N,N-dimethylformamide, hexamethylphosphoric triamide and
1,3-dimethyl-2-imidazolidinone.
[0647] Examples of the hydrocarbon-based solvent include an
aromatic hydrocarbon-based solvent such as toluene and xylene, an
aliphatic hydrocarbon-based solvent such as pentane, hexane,
octane, decane, 2,2,4-trimethylpentane, 2,2,3-trimethylhexane,
perfluorohexane and perfluoroheptane, and an aromatic
hydrocarbon-based solvent such as toluene, xylene, ethylbenzene,
propylbenzene, 1-methylpropylbenzene, 2-methylpropylbenzene,
dimethylbenzene, diethylbenzene, ethylmethylbenzene,
trimethylbenzene, ethyldimethylbenzene and dipropylbenzene. Among
these, an aromatic hydrocarbon-based solvent is preferred.
[0648] A plurality of these solvents may be mixed, or the solvent
may be mixed with a solvent other than those described above or
water and used.
[0649] As for the developer which can be used when performing
negative development, a solvent represented by the following
formula (1) is preferably used.
##STR00087##
[0650] In formula (1), R and R' each independently represents a
hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl
group, an alkoxycarbonyl group, a carboxyl group, a hydroxyl group,
a cyano group or a halogen atom, and R and R' may combine with each
other to form a ring. R and R' each is preferably a hydrogen atom
or an alkyl group, and the alkyl group of R and R' may be
substituted by a hydroxyl group, a carbonyl group, a cyano group or
the like.
[0651] Examples of the solvent represented by formula (1) include
methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate,
amyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl
formate, propyl formate, ethyl lactate, butyl lactate, propyl
lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl
pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl
acetoacetate, ethyl acetoacetate, methyl propionate, ethyl
propionate, propyl propionate, isopropyl propionate, methyl
2-hydroxypropionate and ethyl 2-hydroxypropionate.
[0652] Above all, in the solvent represented by formula (1), R and
R' each is preferably an unsubstituted alkyl group, more preferably
an alkyl acetate, still more preferably butyl acetate.
[0653] The solvent represented by formula (1) may be used in
combination with one or more other solvents. In this case, the
solvent used in combination is not particularly limited as long as
it can be mixed with the solvent represented by formula (1) without
causing separation, and the solvents represented by formula (1) may
be used in combination with each other or the solvent represented
by formula (1) may be used by mixing it with a solvent selected
from other ester-based, ketone-based, alcohol-based, amide-based,
ether-based and hydrocarbon-based solvents. As for the solvent used
in combination, one or more species may be used but from the
standpoint of obtaining a stable performance, one species is
preferably used. In the case where one species of the solvent used
in combination is mixed and used, the mixing ratio between the
solvent represented by formula (1) and the solvent used in
combination is usually from 20:80 to 99:1, preferably from 50:50 to
97:3, more preferably from 60:40 to 95:5, and most preferably from
60:40 to 90:10.
[0654] As for the developer which can be used when performing
negative development, a solvent represented by the following
formula (2) is preferably used.
##STR00088##
[0655] In formula (2), R'' and R'''' each independently represents
a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl
group, an alkoxycarbonyl group, a carboxyl group, a hydroxyl group,
a cyano group or a halogen atom, and R'' and R'''' may combine with
each other to form a ring. R'' and R'''' each is preferably a
hydrogen atom or an alkyl group.
[0656] R''' represents an alkylene group or a cycloalkylene group.
R''' is preferably a hydrogen atom or an alkyl group.
[0657] The alkyl group of R'', R''' and R'''' may be substituted by
a hydroxyl group, a carbonyl group, a cyano group or the like.
[0658] In formula (2), the alkylene group of R''' may have an ether
bond in the alkylene chain.
[0659] Examples of the solvent represented by formula (2) include
propylene glycol monomethyl ether acetate, ethylene glycol
monoethyl ether acetate, ethylene glycol monopropyl ether acetate,
ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl
ether acetate, diethylene glycol monomethyl ether acetate,
diethylene glycol monopropyl ether acetate, diethylene glycol
monophenyl ether acetate, diethylene glycol monobutyl ether
acetate, diethylene glycol monoethyl ether acetate, propylene
glycol monomethyl ether acetate, propylene glycol monoethyl ether
acetate, propylene glycol monopropyl ether acetate,
methyl-3-methoxypropionate, ethyl-3-methoxypropionate,
ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, ethyl
methoxyacetate, ethyl ethoxyacetate, 2-methoxybutyl acetate,
3-methoxybutyl acetate, 4-methoxybutyl acetate,
3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate,
2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl
acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate,
4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate,
3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate
and 4-methyl-4-methoxypentyl acetate.
[0660] The solvent represented by formula (2) may be used in
combination with one or more other solvents. In this case, the
solvent used in combination is not particularly limited as long as
it can be mixed with the solvent represented by formula (2) without
causing separation, and the solvents represented by formula (2) may
be used in combination with each other or the solvent represented
by formula (2) may be used by mixing it with a solvent selected
from other ester-based, ketone-based, alcohol-based, amide-based,
ether-based and hydrocarbon-based solvents. As for the solvent used
in combination, one or more species may be used but from the
standpoint of obtaining a stable performance, one species is
preferably used. In the case where one species of the solvent used
in combination is mixed and used, the mixing ratio between the
solvent represented by formula (2) and the solvent used in
combination is usually from 20:80 to 99:1, preferably from 50:50 to
97:3, more preferably from 60:40 to 95:5, and most preferably from
60:40 to 90:10.
[0661] In view of cost saving of the solvent used for development,
the solvent used at the negative development is preferably an
organic solvent not containing a halogen atom. The content of the
halogen atom-free solvent occupying in the total weight of all
solvents used at the negative development is usually 60 mass % or
more, preferably 80 mass % or more, more preferably 90 mass % or
more, still more preferably 97 mass % or more.
[0662] The boiling point of the solvent used at the negative
development is preferably from 50.degree. C. to less than
250.degree. C.
[0663] The ignition point of the solvent used at the negative
development is preferably 200.degree. C. or more.
[0664] In the developer usable at the negative development, a
surfactant can be added in an appropriate amount, if desired.
[0665] The surfactant is not particularly limited but, for example,
an ionic or nonionic fluorine-containing and/or silicon-containing
surfactant can be used. Examples of such a fluorine-containing
and/or silicon-containing surfactant include the surfactants
described in JP-A-62-36663, JP-A-61-226746, JP-A-61-226745,
JP-A-62-170950, JP-A-63-34540, JP-A-7-230165, JP-A-8-62834,
JP-A-9-54432, JP-A-9-5988 and U.S. Pat. Nos. 5,405,720, 5,360,692,
5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511 and
5,824,451. The surfactant is preferably a nonionic surfactant. The
nonionic surfactant is not particularly limited, but a
fluorine-containing surfactant or a silicon-containing surfactant
is more preferred.
[0666] The amount of the surfactant used is usually from 0.001 to 5
mass %, preferably from 0.005 to 2 mass %, more preferably from
0.01 to 0.5 mass %, based on the entire amount of the
developer.
[0667] As regards the negative development method, for example, a
method of dipping a substrate in a bath filled with the developer
for a fixed time (dip method), a method of raising the developer on
a substrate surface by the effect of a surface tension and keeping
it still for a fixed time, thereby performing the development
(puddle method), a method of spraying the developer on a substrate
surface (spray method), and a method of continuously ejecting the
developer on a substrate rotating at a constant speed while
scanning the developer ejecting nozzle at a constant rate (dynamic
dispense method) may be applied.
[0668] After the step of performing negative development, a step of
stopping the development by the replacement with another solvent
may be practiced.
[0669] A step of washing the resist film with a rinsing solution
containing an organic solvent is preferably provided after the step
of performing negative development.
[0670] In the washing step after negative development, a rinsing
solution containing at least one kind of a solvent selected from a
hydrocarbon-based solvent, a ketone-based solvent, an ester-based
solvent, an alcohol-based solvent, an amide-based solvent and an
ether-based solvent may be usually used.
[0671] In the present invention, the hydrocarbon-based solvent
indicates a hydrocarbon solvent having no substituent, the
ketone-based solvent indicates a solvent having a ketone group
within the molecule, the ester-based solvent indicates a solvent
having an ester group within the molecule, the alcohol-based
solvent indicates a solvent having an alcoholic hydroxyl group
within the molecule, the amide-based solvent indicates a solvent
having an amide group within the molecule, and the ether-based
solvent indicates a solvent having an ether bond within the
molecule. Some of these solvents have a plurality of kinds of the
functional groups described above within one molecule and in this
case, the solvent comes under all solvent species corresponding to
the functional groups contained in the solvent.
[0672] For example, diethylene glycol monomethyl ether comes under
both an alcohol-based solvent and an ether-based solvent in the
classification above.
[0673] For example, there may be used a ketone-based solvent such
as 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone,
4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone,
cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl
ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone,
ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl
naphthyl ketone, isophorone and propylene carbonate; and an
ester-based solvent such as methyl acetate, butyl acetate, ethyl
acetate, isopropyl acetate, amyl acetate, propylene glycol
monomethyl ether acetate, ethylene glycol monoethyl ether acetate,
diethylene glycol monobutyl ether acetate, diethylene glycol
monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl
acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl
formate, butyl formate, propyl formate, ethyl lactate, butyl
lactate and propyl lactate.
[0674] Examples of the alcohol-based solvent include an alcohol
such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl
alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol,
isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl
alcohol and n-decanol; a glycol-based solvent such as ethylene
glycol, diethylene glycol and triethylene glycol; and a glycol
ether-based solvent such as ethylene glycol monomethyl ether,
propylene glycol monomethyl ether, ethylene glycol, propylene
glycol, diethylene glycol monomethyl ether, triethylene glycol
monoethyl ether and methoxymethyl butanol.
[0675] Examples of the ether-based solvent include, in addition to
the glycol ether-based solvents above, dioxane and
tetrahydrofuran.
[0676] Examples of the amide-based solvent which can be used
include N-methyl-2-pyrrolidone, N,N-dimethylacetamide,
N,N-dimethylformamide, hexamethylphosphoric triamide and
1,3-dimethyl-2-imidazolidinone.
[0677] Examples of the hydrocarbon-based solvent include an
aromatic hydrocarbon-based solvent such as toluene and xylene, and
an aliphatic hydrocarbon-based solvent such as pentane, hexane,
octane and decane.
[0678] The rinsing solution containing an organic solvent
preferably uses at least one kind of a solvent selected from a
hydrocarbon-based solvent, a ketone-based solvent, an ester-based
solvent, an alcohol-based solvent and an amide-based solvent. The
rinsing solution may use, more preferably, at least one kind of a
solvent selected from an alcohol-based solvent and an ester-based
solvent. The rinsing solution is most preferably a rinsing solution
containing a monohydric alcohol having a carbon number of 6 to 8.
The monohydric alcohol having a carbon number of 6 to 8, which is
contained in the rinsing solution used in the washing step after
negative development, includes a linear, branched or cyclic
monohydric alcohol, and specific examples of the monohydric alcohol
which can be used include a 1-hexanol, 1-heptanol, 1-octanol,
2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol,
4-octanol and benzyl alcohol, with 1-hexanol, 2-heptanol and
2-hexanol being preferred, and 1-hexanol and 2-hexanol being more
preferred.
[0679] A plurality of these solvents may be mixed, or the solvent
may be mixed with an organic solvent other than those described
above and used.
[0680] The solvent may be mixed with water, and the water content
in the rinsing solution is usually 30 mass % or less, preferably 10
mass % or less, more preferably 5 mass % or less, and most
preferably 3 mass % or less. By setting the water content to 30
mass % or less, good development characteristics can be
obtained.
[0681] In the rinsing solution, a surfactant can be added in an
appropriate amount, if desired.
[0682] The surfactant is not particularly limited but, for example,
an ionic or nonionic fluorine-containing and/or silicon-containing
surfactant can be used.
[0683] The amount of the surfactant used is usually from 0.001 to 5
mass %, preferably from 0.005 to 2 mass %, more preferably from
0.01 to 0.5 mass %, based on the entire amount of the
developer.
[0684] In the step of washing the resist film with a rinsing
solution, the resist after negative development is washed using the
above-described organic solvent-containing rinsing solution. The
washing treatment method is not particularly limited but, for
example, a method of continuously ejecting the rinsing solution on
a substrate rotating at a constant speed (rotary coating method), a
method of dipping a substrate in a bath filled with the rinsing
solution for a fixed time (dip method), and a method of spraying
the rinsing solution of a substrate surface (spray method) may be
applied.
[0685] Also, a treatment of removing the developer or rinsing
solution adhering on the pattern by using a supercritical fluid may
be performed after the development or rinsing treatment.
[0686] Furthermore, after the development, the rinsing or the
treatment with a supercritical fluid, a heat treatment may be
performed for removing the solvent remaining in the pattern. The
heating temperature is not particularly limited as long as a good
resist pattern is obtained, and the heating temperature is usually
from 40 to 160.degree. C. The heat treatment may be performed a
plurality of times.
EXAMPLES
[0687] The present invention is described in greater detail below
by referring to Examples, but the present invention should not be
construed as being limited thereto.
Example 1
[0688] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer by a spin
coater and baked at 205.degree. C. for 60 seconds to form a 78-nm
antireflection film, and a commercially available product,
FAiRS-9101A12 (an ArF positive resist composition, produced by
FUJIFILM Electronic Materials Co., Ltd.), was coated thereon and
baked at 100.degree. C. for 60 seconds to form a 150-nm resist
film. The obtained wafer was subjected to pattern exposure at 25
[mJ/cm.sup.2] by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with butyl acetate (negative developer) for 30
seconds (negative development), and rinsed with decane for 30
seconds to obtain a resist pattern having a pitch of 200 nm and a
line width of 100 nm.
Synthesis Example 1
Synthesis of Resin (A1)
[0689] Under a nitrogen stream, 8.4 g of methyl isobutyl ketone was
charged into a three-neck flask and heated at 80.degree. C.
Thereto, a solution obtained by dissolving 9.4 g of
2-cyclohexylpropan-2-yl methacrylate, 4.7 g of
3-hydroxy-1-adamantyl methacrylate, 6.8 g of
.beta.-methacryloyloxy-.gamma.-butyrolactone and
azobisisobutyronitrile corresponding to 6 mol % based on the entire
monomer amount, in 75.3 g of methyl isobutyl ketone was added
dropwise over 6 hours. After the completion of dropwise addition,
the reaction was further allowed to proceed at 80.degree. C. for 2
hours. The resulting reaction solution was left standing to cool
and then, poured in 720 ml of heptane/80 ml of ethyl acetate, and
the powder precipitated was collected by filtration and dried, as a
result, 18.3 g of Resin (A1) was obtained. The weight average
molecular weight of the obtained resin was 9,300 and the dispersity
(Mw/Mn) was 1.98.
(Resin A1)
##STR00089##
[0690] Positive Resist Composition (A):
[0691] A solution having a solid content concentration of 5.8 mass
% obtained by dissolving the components shown below in a mixed
solvent of polyethylene glycol monomethyl ether
acetate/polyethylene glycol monomethyl ether (60:40) was filtered
through a 0.1-.mu.m polyethylene filter to prepare Positive Resist
Composition (A).
[0692] Resin (A1): 1.83 g, triphenylsulfonium nonaflate: 69.6 mg,
diphenylaniline: 8.7 mg, and PF6320 (fluorine-containing surfactant
produced by OMNOVA): 1.7 mg.
Positive Resist Composition (B):
[0693] Positive Resist Composition (B) was prepared using Resin
(A2) shown below in place of Resin (A1).
(Resin A2)
##STR00090##
[0695] Weight average molecular weight: 8,000
[0696] Dispersity: 1.81
[0697] Molar ratio: 40/20/40
Positive Resist Composition (C):
[0698] Positive Resist Composition (C) was prepared using Resin (B)
shown below in place of Resin (A1).
(Resin B)
##STR00091##
[0700] Weight average molecular weight: 9,500
[0701] Dispersity: 1.85
[0702] Molar ratio: 40/20/40
Positive Resist Composition (D):
[0703] Positive Resist Composition (D) was prepared using Resin (C)
shown below in place of Resin (A1).
(Resin C)
##STR00092##
[0705] Weight average molecular weight: 8,000
[0706] Dispersity: 1.80
[0707] Molar ratio: 50/50
Example 2
[0708] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (B) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with an aqueous tetramethylammonium hydroxide
solution (2.38 mass %) (positive developer) for 30 seconds
(positive development), and rinsed with pure water for 30 seconds
to obtain a pattern having a pitch of 1,000 nm and a line width of
750 nm. Furthermore, the resist film was developed with a 2:3 (by
mass) solution of butyl acetate/2-hexanol (negative developer) for
30 seconds (negative development) to obtain a 250-nm (1:1) resist
pattern.
Example 3
[0709] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (A) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 20 [mJ/cm.sup.2] by using an ArF excimer laser
scanner (NA: 0.75). Thereafter, the resist film was heated at
130.degree. C. for 60 seconds, developed with an aqueous
tetramethylammonium hydroxide solution (2.38 mass %) (positive
developer) for 30 seconds (positive development, and rinsed with
pure water for 30 seconds to obtain a pattern having, as shown in
FIG. 11, a pitch of 600 nm and a line width of 450 nm. Furthermore,
the resist film was subjected to second exposure at 56
[mJ/cm.sup.2] through the same mask for pattern formation as used
in the first exposure, heated at 120.degree. C. for 60 seconds and
developed with a 1:2 (by mass) solution of butyl acetate/2-hexanol
(negative developer) for 30 seconds (negative development) to
obtain a 150-nm (1:1) resist pattern.
Example 4
[0710] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (B) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 18 [mJ/cm.sup.2] by using an ArF excimer laser
scanner (NA: 0.75). Thereafter, the resist film was heated at
135.degree. C. for 60 seconds, developed with a 2:3 (by mass)
solution of butyl acetate/2-hexanol (negative developer) for 30
seconds (negative development) to obtain a pattern having a pitch
of 600 nm and a line width of 450 nm. Furthermore, the resist film
was subjected to second exposure at 45 [mJ/cm.sup.2] through the
same mask for pattern formation as used in the first exposure,
heated at 90.degree. C. for 60 seconds, developed with an aqueous
tetramethylammonium hydroxide solution (2.38 mass %) (positive
developer) for 30 seconds (positive development, and rinsed with
pure water for 30 seconds to obtain a 150-nm (1:1) resist
pattern.
Example 5
[0711] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (B) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with an aqueous tetramethylammonium hydroxide
solution (2.38 mass %) for 30 seconds, and rinsed with pure water
for 30 seconds to obtain a pattern having a pitch of 920 nm and a
line width of 690 nm. Furthermore, the resist film was developed
with a 2:3 (by mass) solution of butyl acetate/2-hexanol for 30
seconds and then rinsed with 2-hexanol for 30 seconds to obtain a
230-nm (1:1) resist pattern.
Example 6
[0712] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (C) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with an aqueous tetramethylammonium hydroxide
solution (2.38 mass %) for 30 seconds, and rinsed with pure water
for 30 seconds to obtain a pattern having a pitch of 880 nm and a
line width of 660 nm. Furthermore, the resist film was developed
with a 2:3 (by mass) solution of butyl acetate/2-hexanol for 30
seconds and then rinsed with 2-hexanol for 30 seconds to obtain a
220-nm (1:1) resist pattern.
Example 7
[0713] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (A) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 20 [mJ/cm.sup.2] by using an ArF excimer laser
scanner (NA: 0.75). Thereafter, the resist film was heated at
130.degree. C. for 60 seconds, developed with an aqueous
tetramethylammonium hydroxide solution (2.38 mass %) for 30
seconds, and rinsed with pure water for 30 seconds to obtain a
pattern having a pitch of 560 nm and a line width of 420 nm.
Furthermore, the resist film was subjected to second exposure at 56
[mJ/cm.sup.2] through the same mask for pattern formation as used
in the first exposure, heated at 120.degree. C. for 60 seconds,
developed with butyl acetate for 30 seconds and then rinsed with
1-hexanol for 30 seconds to obtain a 140-nm (1:1) resist
pattern.
Example 8
[0714] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (B) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 18 [mJ/cm.sup.2] by using an ArF excimer laser
scanner (NA: 0.75). Thereafter, the resist film was heated at
135.degree. C. for 60 seconds, developed with a 2:3 (by mass)
solution of butyl acetate/2-hexanol for 30 seconds, and rinsed with
2-hexanol for 30 seconds to obtain a pattern having a pitch of 560
nm and a line width of 420 nm. Furthermore, the resist film was
subjected to second exposure at 45 [mJ/cm.sup.2] through the same
mask for pattern formation as used in the first exposure, heated at
90.degree. C. for 60 seconds, developed with an aqueous
tetramethylammonium hydroxide solution (2.38 mass %) for 30
seconds, and rinsed with pure water for 30 seconds to obtain a
140-nm (1:1) resist pattern.
Example 9
[0715] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (B) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds and developed with a 2:3 (by mass) solution of butyl
acetate/2-hexanol for 30 seconds to obtain a pattern having a pitch
of 1,000 nm and a line width of 750 nm. Furthermore, the resist
film was developed with an aqueous tetramethylammonium hydroxide
solution (2.38 mass %) for 30 seconds, and rinsed with pure water
for 30 seconds to obtain a 250-nm (1:1) resist pattern.
Example 10
[0716] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (B) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure using a ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with an aqueous tetramethylammonium hydroxide
solution (2.38 mass %) for 30 seconds and rinsed with pure water
for 30 seconds to obtain a pattern having a pitch of 1,200 nm and a
line width of 900 nm. Furthermore, the resist film was developed
with a 2:3 (by mass) solution of butyl acetate/2-hexanol for 30
seconds to obtain a 300-nm (1:1) resist pattern.
Example 11
[0717] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (D) prepared above was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure using a ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with an aqueous tetramethylammonium hydroxide
solution (2.38 mass %) for 30 seconds and rinsed with pure water
for 30 seconds to obtain a pattern having a pitch of 1,280 nm and a
line width of 960 nm. Furthermore, the resist film was developed
with a 2:3 (by mass) solution of butyl acetate/2-hexanol for 30
seconds to obtain a 320-nm (1:1) resist pattern.
Example 12
[0718] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and a commercially available product, FAiRS-9101A12 (an ArF
positive resist composition, produced by FUJIFILM Electronic
Materials Co., Ltd.), was coated thereon by a spin coater and baked
at 100.degree. C. for 60 seconds to form a 150-nm resist film. The
obtained wafer was subjected to pattern exposure at 25
[mJ/cm.sup.2] by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with butyl acetate (negative developer) for 30
seconds (negative development) and rinsed with 1-hexanol for 30
seconds to obtain a pattern having a pitch of 180 nm and a line
width of 90 nm.
[0719] Structures of Resins (E) to (R) used in Examples 13 to 26
are shown below.
##STR00093## ##STR00094## ##STR00095## ##STR00096## ##STR00097##
##STR00098##
[0720] The compositional ratio (molar ratio, corresponding to
repeating units from the left), weight average molecular weight and
dispersity of each of Resins (E) to (R) are shown in Table 1
below.
TABLE-US-00001 TABLE 1 Weight Average Resin Compositional Ratio
Molecular Weight Dispersity E 50:40:10 10,000 1.52 F 30:20:50
12,500 1.61 G 40:10:50 14,300 1.75 H 40:15:35:10 11,100 1.64 I
60:30:10 9,200 1.58 J 30:50:20 7.600 1.44 K 40:10:40:10 8,300 1.82
L 40:15:35:5:5 7,200 1.77 M 60:20:20 6,000 1.71 N 40:15:45 5,000
1.69 O 30:30:40 18,000 2.23 P 40:5:55 9,000 1.7 Q 50:50 8,000 1.22
R 50:50 5,500 1.41
Positive Resist Compositions (E) to (R):
[0721] Positive Resist Compositions (E) to (R) were prepared by
filtering respective solutions according to the formulation shown
in Table 2 below through a 0.1 .mu.m polyethylene filter.
TABLE-US-00002 TABLE 2 Positive Concen- Resist Acid Ratio tration
of Composi- Resin Gener- Amount Amount by Solid Surfac- Amount tion
(1.83 g) ator Added Basic Compound Added Solvent Mass Contents tant
Added E E PAG-1 130 mg N,N-dibutylaniline 10.5 mg PGMEA/PGME 60/40
3.0 wt % W-1 1.7 mg F F z61/ 70.0 mg/ diazabicyclo- 4.3 mg
PGMBA/PGME 60/40 4.3 wt % W-2 3.4 mg PAG-2 52.0 mg [4.3.0]nonene G
G z2 80 mg tris(methoxy- 6.3 mg PGMEA/cyclo- 40/60 4.0 wt % W-3 5.1
mg ethoxy]ethylamine hexanone H H z63 52.1 mg E-1 13.5 mg
PGMEA/PGME 60/40 8.0 wt % W-4 0.8 mg I I PAG-3/ 32.5 mg/
triethanolamine 3.5 mg PGMEA/PGME 80/20 6.2 wt % W-4 0.07 mg z2
41.2 mg J J z20/ 31.5 mg/ N-phenyldi- 4.2 mg/ PGMEA/PGME 20/80 5.5
wt % W-1 17 mg PAG-4 51.3 mg ethanolamine/N,N- 4.2 mg
dibutylaniline K K PAG-5 65.0 mg N-cyanoethylaniline 5.5 mg PGME --
5.2 wt % W-2 1.7 mg L L z8/z42 89.5 mg/ 4-dimethyl- 6.3 mg
.gamma.-butyrolactone -- 6.6 wt % W-3 1.7 mg 11 mg aminopyridine M
M PAG-6 118.2 mg N-(2-cyanoethyl)-N- 10.1 mg cyclohexanone -- 5.8
wt % W-4 8.2 mg ethylaniline N N PAG-7/ 50.3 mg/ 2-phenylbenz- 8.3
mg PGMEA/cyclo- 80/20 5.8 wt % W-4 1.2 mg z2 30.3 mg imidazole
hexanone O O PAG-8 130 mg dicyclohexyl- 2.1 mg/ ethyl lactate --
5.8 wt % W-4 3.2 mg methylamine/2,6- 6.5 mg diisopropylaniline P P
PAG-9 100.2 mg tetrabutylammonium 12.0 mg PGMEA/ 95/5 5.8 wt % W-4
0.8 mg hydroxide propylene carbonate Q Q PAG-10 145 mg
2,6-diisopropylaniline 6.1 mg PGMEA/PGME 60/40 3.7 wt % W-4 1.2 mg
R R z7 300 mg trioctylamiae 11.5 mg PGMEA/PGME 80/20 2.5 wt % W-1
1.2 mg
[0722] Abbreviations in the Table indicate the followings.
[Acid Generator]
##STR00099## ##STR00100##
[0723] [Basic Compound]
##STR00101##
[0724] [Solvent]
[0725] PGMEA: propylene glycol monomethyl ether acetate [0726]
PGME: propylene glycol monomethyl ether
[Surfactant]
[0726] [0727] W-1: Megafac F-176 (produced by Dainippon Ink &
Chemicals, Inc.) (fluorine-containing surfactant) [0728] W-2:
Megafac R08 (produced by Dainippon Ink & Chemicals, Inc.)
(fluorine- and silicon-containing surfactant) [0729] W-3:
Polysiloxane Polymer KP-341 (produced by Shin-Etsu Chemical Co.,
Ltd.) (silicon-containing surfactant) [0730] W-4: PF6320 (produced
by OMNOVA) (fluorine-containing surfactant)
Example 13
[0731] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (E) prepared was coated
thereon by a spin coater and baked at 90.degree. C. for 80 seconds
to form a 80-nm resist film. The obtained wafer was subjected to
exposure at 18 [mJ/cm.sup.2] through a mask for pattern formation
by using PAS5500/1250i equipped with a lens of NA=0.85, produced by
ASML, as an ArF excimer laser scanner. Thereafter, the resist film
was heated at 120.degree. C. for 60 seconds, developed with butyl
acetate (negative developer) for 30 seconds (negative development),
and rinsed with 1-hexanol for 30 seconds to obtain a pattern having
a pitch of 320 nm and a line width of 240 nm. Furthermore, the
resist film was developed with an aqueous tetramethylammonium
hydroxide solution (0.05 mass %) (positive developer) for 30
seconds (positive development) and then rinsed with pure water for
30 seconds, whereby a resist pattern (1:1) of 80 nm was
obtained.
Example 14
[0732] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (F) prepared was coated
thereon by a spin coater and baked at 120.degree. C. for 60 seconds
to form a 120-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with methyl isobutyl ketone (negative developer)
for 30 seconds (negative development), and rinsed with 2-heptanol
for 30 seconds to obtain a pattern having a pitch of 200 nm and a
line width of 120 nm.
Example 15
[0733] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (G) prepared was coated
thereon by a spin coater and baked at 110.degree. C. for 60 seconds
to form a 100-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 100.degree. C. for 80
seconds, developed with ethyl lactate (negative developer) for 30
seconds (negative development), and rinsed with 2-heptanol for 60
seconds to obtain a pattern having a pitch of 200 nm and a line
width of 120 nm.
Example 16
[0734] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (H) prepared was coated
thereon by a spin coater and baked at 105.degree. C. for 60 seconds
to form a 220-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 90.degree. C. for 60
seconds, developed with a 1:1 (by mass) solution of butyl
acetate/2-hexanone (negative developer) for 30 seconds (negative
development), and rinsed with decane for 30 seconds to obtain a
pattern having a pitch of 200 nm and a line width of 100 nm.
Example 17
[0735] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (I) prepared was coated
thereon by a spin coater and baked at 95.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 110.degree. C. for 60
seconds, developed with a 7:3 (by mass) solution of butyl
acetate/dihexyl ether (negative developer) for 30 seconds (negative
development), and rinsed with 1-hexanol for 30 seconds to obtain a
pattern having a pitch of 240 nm and a line width of 100 nm.
Example 18
[0736] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (J) prepared was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 105.degree. C. for 60
seconds, developed with methyl ethyl ketone (negative developer)
for 30 seconds (negative development), and rinsed with 1-hexanol
for 30 seconds to obtain a pattern having a pitch of 260 nm and a
line width of 130 nm.
Example 19
[0737] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (K) prepared was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with ethyl-3-ethoxypropionate (negative
developer) for 30 seconds (negative development), and rinsed with
1-hexanol for 30 seconds to obtain a pattern having a pitch of 240
nm and a line width of 120 nm.
Example 20
[0738] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (L) prepared was coated
thereon by a spin coater and baked at 100.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 17 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with a 95:5 (by mass) solution of isoamyl
acetate/decane (negative developer) for 60 seconds (negative
development), and rinsed with 1-hexanol for 15 seconds to obtain a
pattern having a pitch of 400 nm and a line width of 300 nm.
Furthermore, the resist film was subjected to second exposure at 3
[mJ/cm.sup.2] without intervention of a mask for pattern formation,
developed with an aqueous tetramethylammonium hydroxide solution
(0.238 mass %) (positive developer) for 20 seconds (positive
development), and rinsed with pure water for 30 seconds to obtain a
resist pattern (1:1) of 100 nm.
Example 21
[0739] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (M) prepared was coated
thereon by a spin coater and baked at 130.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 100.degree. C. for 60
seconds, developed with a 3:2 (by mass) solution of
cyclohexanone/1-hexanol (negative developer) for 15 seconds
(negative development), and rinsed with a 1:1 (by mass) solution of
2-heptanol/decane for 40 seconds to obtain a pattern having a pitch
of 240 nm and a line width of 120 nm.
Example 22
[0740] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (N) prepared was coated
thereon by a spin coater and baked at 105.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 90.degree. C. for 60
seconds, developed with a 1:3 (by mass) solution of diethylene
glycol monoethyl ether acetate/methyl isobutyl ketone (negative
developer) for 10 seconds (negative development), and rinsed with a
1:1 (by mass) solution of 1-hexanol/2-heptanol for 60 seconds to
obtain a pattern having a pitch of 240 nm and a line width of 120
nm.
Example 23
[0741] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (O) prepared was coated
thereon by a spin coater and baked at 120.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 25 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 110.degree. C. for 60
seconds, developed with a 95:5 (by mass) solution of amyl
acetate/isopropanol (negative developer) for 30 seconds (negative
development), and rinsed with 1-hexanol for 30 seconds to obtain a
pattern having a pitch of 200 nm and a line width of 100 nm.
Example 24
[0742] An organic antireflection film, ARC29A (produced by Nissan
Chemical Industries, Ltd.), was coated on a silicon wafer and baked
at 205.degree. C. for 60 seconds to form a 78-nm antireflection
film, and Positive Resist Composition (P) prepared was coated
thereon by a spin coater and baked at 90.degree. C. for 60 seconds
to form a 150-nm resist film. The obtained wafer was subjected to
pattern exposure at 17 [mJ/cm.sup.2] through a mask for pattern
formation by using an ArF excimer laser scanner (NA: 0.75).
Thereafter, the resist film was heated at 120.degree. C. for 60
seconds, developed with an aqueous tetramethylammonium hydroxide
solution (0.238 mass %) (positive developer) for 30 seconds
(positive development), and rinsed with pure water for 30 seconds
to obtain a pattern having a pitch of 480 nm and a line width of
360 nm. Furthermore, the resist film was subjected to second
exposure at 3 [mJ/cm.sup.2] without intervention of a mask for
pattern formation, developed with butyl acetate (negative
developer) for 30 seconds (negative development), rinsed with
1-hexanol for 20 seconds, and then heated at 90.degree. C. for 90
seconds to obtain a resist pattern (1:1) of 120 nm.
[0743] The dimensions of patterns formed in Examples 1 to 24 are
shown in Table 3 below. A smaller value indicates higher
performance.
[0744] After pattern formation, the top surface of line pattern and
the space portion were observed using a length-measuring scanning
electron microscope (S9380II, manufactured by Hitachi, Ltd.), and
the pattern was rated A when the resist residue was not observed at
all, rated B when scarcely observed, and rated C when slightly
observed. The results are shown in Table 3.
[0745] The resist pattern profile was observed by a scanning
electron microscope and rated B when the resist pattern at each
resolved line width was partially lost or chipped from the middle
or top of the pattern, and rated A when chipping was not observed.
The results are shown in Table 3.
TABLE-US-00003 TABLE 3 Example Pattern Residue Chipping 1 100 nm
L/S A B 2 250 nm L/S B B 3 150 nm L/S B B 4 150 nm L/S B A 5 230 nm
L/S A B 6 220 nm L/S A B 7 140 nm L/S A B 8 140 nm L/S A A 9 250 nm
L/S B A 10 300 nm L/S B B 11 320 nm L/S C B 12 90 nm L/S A B 13 80
nm L/S A A 14 120 nm L/S B B 15 120 nm L/S A B 16 100 nm L/S A B 17
100 nm L/S A B 18 130 nm L/S B B 19 120 nm L/S A B 20 100 nm L/S A
B 21 120 nm L/S B B 22 120 nm L/S B B 23 100 nm L/S A B 24 120 nm
L/S A B
[0746] As apparent from these Examples, by virtue of the
combination of negative development and positive resist composition
of the present invention or the combination of positive
development, negative development and positive resist composition
of the present invention, a good pattern resolution performance is
obtained and the problem of resist residue is overcome.
Particularly, it is seen that when a resin having a monocyclic or
polycyclic alicyclic hydrocarbon structure is used as the positive
resist composition, a higher pattern resolution performance is
obtained and the generation of residue is more suppressed.
[0747] Furthermore, it is revealed that when development is
performed twice and the order of two development operations is such
that negative development is performed first and positive
development is next performed, chipping of the resist pattern can
be suppressed.
Example 25
[0748] On a silicon wafer treated with hexamethyldisilazane,
Positive Resist Composition (Q) was coated by a spin coater and
baked at 90.degree. C. for 60 seconds to form a 100-nm resist film.
The obtained wafer was subjected to surface exposure using EUV
light (wavelength: 13.5 nm) by changing the exposure dose in steps
of 0.5 mJ in the range from 0 to 10.0 mJ and then heated at
120.degree. C. for 60 seconds. Thereafter, the dissolution rate at
each exposure dose was measured using butyl acetate (negative
developer) to obtain a sensitivity curve. The exposure dose when
the dissolution rate of the resist was saturated in this
sensitivity curve was taken as the sensitivity and also, the
dissolution contrast (.gamma. value) was calculated from the
gradient in the straight line part of the sensitivity curve. As the
.gamma. value is larger, the dissolution contrast is more
excellent. The results obtained are shown in Table 4 below.
Example 26
[0749] On a silicon wafer treated with hexamethyldisilazane,
Positive Resist Composition (R) was coated by a spin coater and
baked at 100.degree. C. for 60 seconds to form a 50-nm resist film.
The obtained wafer was subjected to surface exposure using EUV
light (wavelength: 13.5 nm) by changing the exposure dose in steps
of 0.5 mJ in the range from 0 to 10.0 mJ and then heated at
100.degree. C. for 60 seconds. Thereafter, the dissolution rate at
each exposure dose was measured using butyl acetate (negative
developer) to obtain a sensitivity curve. The exposure dose when
the dissolution rate of the resist was saturated in this
sensitivity curve was taken as the sensitivity and also, the
dissolution contrast (.gamma. value) was calculated from the
gradient in the straight line part of the sensitivity curve. As the
.gamma. value is larger, the dissolution contrast is more
excellent. The results obtained are shown in Table 4 below.
TABLE-US-00004 TABLE 4 Example Sensitivity .gamma. value 25 5.4
mJ/cm.sup.2 7.1 26 2.5 mJ/cm.sup.2 10.3
[0750] As apparent from the results in Table 4, by virtue of the
combination of negative development and positive resist composition
of the present invention, good dissolution contrast and high
sensitivity are obtained even in the characteristic evaluation by
the irradiation with EUV light.
[0751] According to the present invention, a method of stably
forming a high-precision fine pattern, a positive resist
composition for multiple development used in the method, a
developer for negative development used in the method, and a
rinsing solution for negative development used in the method can be
provided.
[0752] The entire disclosure of each and every foreign patent
application from which the benefit of foreign priority has been
claimed in the present application is incorporated herein by
reference, as if fully set forth.
* * * * *