U.S. patent application number 12/529341 was filed with the patent office on 2010-03-18 for positive-working radiation-sensitive composition and method for resist pattern formation using the composition.
Invention is credited to Yuusuke Anno, Nobuji Matsumura, Atsushi Nakamura, Yukio Nishimura, Kaori Sakai, Makoto Sugiura, Gouji Wakamatsu.
Application Number | 20100068650 12/529341 |
Document ID | / |
Family ID | 39788429 |
Filed Date | 2010-03-18 |
United States Patent
Application |
20100068650 |
Kind Code |
A1 |
Nishimura; Yukio ; et
al. |
March 18, 2010 |
POSITIVE-WORKING RADIATION-SENSITIVE COMPOSITION AND METHOD FOR
RESIST PATTERN FORMATION USING THE COMPOSITION
Abstract
A method of patterning using double exposure patterning in a
liquid immersion lithographic process is provided. The patterning
method comprises a step of forming a first pattern on a substrate
using a first resist layer forming composition, a step of making
the first pattern inactive, a step of forming a second pattern on a
substrate on which a pattern has been formed using a second resist
layer forming composition and exposing the second resist layer to
radiation, and a step of developing the exposed resist layer to
form a second pattern in the space area of the first pattern. The
first resist layer forming composition contains a cross-linking
agent which accelerates conversion of the first layer from
positive-working to negative-working.
Inventors: |
Nishimura; Yukio; (Tokyo,
JP) ; Sakai; Kaori; (Tokyo, JP) ; Matsumura;
Nobuji; (Tokyo, JP) ; Sugiura; Makoto; (Tokyo,
JP) ; Nakamura; Atsushi; (Tokyo, JP) ;
Wakamatsu; Gouji; (Tokyo, JP) ; Anno; Yuusuke;
(Tokyo, JP) |
Correspondence
Address: |
DITTHAVONG MORI & STEINER, P.C.
918 Prince Street
Alexandria
VA
22314
US
|
Family ID: |
39788429 |
Appl. No.: |
12/529341 |
Filed: |
March 17, 2008 |
PCT Filed: |
March 17, 2008 |
PCT NO: |
PCT/JP2008/054881 |
371 Date: |
August 31, 2009 |
Current U.S.
Class: |
430/280.1 ;
430/270.1; 430/285.1; 430/287.1; 430/326 |
Current CPC
Class: |
G03F 7/2041 20130101;
G03F 7/0035 20130101; H01L 21/0271 20130101; G03F 7/0397 20130101;
G03F 7/2024 20130101; G03F 7/40 20130101 |
Class at
Publication: |
430/280.1 ;
430/270.1; 430/287.1; 430/285.1; 430/326 |
International
Class: |
G03F 7/039 20060101
G03F007/039; G03F 7/40 20060101 G03F007/40 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2007 |
JP |
2007-084586 |
Feb 12, 2008 |
JP |
2008-030850 |
Claims
1. A positive-working radiation-sensitive resin composition
comprising (A) a crosslinking agent, (B1) a polymer containing an
acid-unstable group (not containing a crosslinking group), (C) a
radiation-sensitive acid generator, and (D) a solvent, the
positive-working radiation-sensitive resin composition being used
for forming a first resist layer used in a method of forming a
resist pattern which comprises: (1) a step of forming a first
resist pattern by forming a first resist layer on a substrate using
the positive-working radiation-sensitive resin composition for
forming the first resist layer, selectively exposing the first
resist layer to radiation through a mask, and developing the
exposed first resist layer, (2) a step of making the first resist
pattern inactive to radiation or insolubilizing the first resist
pattern in an alkaline developer or a positive-working
radiation-sensitive resin composition for forming a second resist
layer, (3) a step of forming a second resist layer on the substrate
on which the first resist pattern has been formed using the
positive-working radiation-sensitive resin composition for forming
the second resist layer, and selectively exposing the second resist
layer to radiation through a mask in the space area of the first
resist pattern, and (4) a step of forming a second resist pattern
in the space area of the first resist pattern by developing the
exposed second resist layer.
2. The positive-working radiation-sensitive resin composition
according to claim 1, wherein the crosslinking agent (A) is: a
compound having two or more groups shown by the following formula
(1), ##STR00046## wherein R.sup.1 and R.sup.2 represent a hydrogen
atom or a group shown by the following formula (2), at least one of
R.sup.1 and R.sup.2 being a group shown by the following formula
(2), ##STR00047## wherein R.sup.3 and R.sup.4 represent a hydrogen
atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxyalkyl
group having 1 to 6 carbon atoms, or R.sup.3 and R.sup.4 bond
together to form a ring having 2 to 10 carbon atoms, and R.sup.5
represents a hydrogen atom or an alkyl group having 1 to 6 carbon
atoms, a compound having two or more epoxy groups or oxetane
groups, or a compound having two or more vinyl groups and a
skeleton shown by any one of the following formulas (12-1) to
(12-4). ##STR00048##
3-10. (canceled)
11. The positive-working radiation-sensitive resin composition
according to claim 1, wherein the amount of the crosslinking agent
(A) is 1 to 30 mass % of the solid component of the
composition.
12. The positive-working radiation-sensitive resin composition
according to claim 2, wherein the amount of the crosslinking agent
(A) is 1 to 30 mass % of the solid component of the
composition.
13. The positive-working radiation-sensitive resin composition
according to claim 1, wherein the polymer (B1) has: a repeating
unit which contains an acid-unstable group shown by the following
formula (3), ##STR00049## wherein R.sup.6 represents a hydrogen
atom, a methyl group, or a trifluoromethyl group, R.sup.7
individually represents a monovalent alicyclic hydrocarbon group
having 4 to 20 carbon atoms, a derivative thereof, or a linear or
branched alkyl group having 1 to 4 carbon atoms, and a repeating
unit which contains a lactone structure shown by at least one of
the following formulas (4-1) to (4-6), ##STR00050## wherein R.sup.8
represents a hydrogen atom or a substituted or unsubstituted alkyl
group having 1 to 4 carbon atoms, R.sup.9 represents a hydrogen
atom or a methoxy group, A represents a single bond or a methylene
group, B represents an oxygen atom or a methylene group, p is an
integer of 1 to 3, and m is 0 or 1.
14. The positive-working radiation-sensitive resin composition
according to claim 2, wherein the polymer (B1) has: a repeating
unit which contains an acid-unstable group shown by the following
formula (3), ##STR00051## wherein R.sup.6 represents a hydrogen
atom, a methyl group, or a trifluoromethyl group, R.sup.7
individually represents a monovalent alicyclic hydrocarbon group
having 4 to 20 carbon atoms, a derivative thereof, or a linear or
branched alkyl group having 1 to 4 carbon atoms, and a repeating
unit which contains a lactone structure shown by at least one of
the following formulas (4-1) to (4-6), ##STR00052## wherein R.sup.8
represents a hydrogen atom or a substituted or unsubstituted alkyl
group having 1 to 4 carbon atoms, R.sup.9 represents a hydrogen
atom or a methoxy group, A represents a single bond or a methylene
group, B represents an oxygen atom or a methylene group, p is an
integer of 1 to 3, and m is 0 or 1.
15. The positive-working radiation-sensitive resin composition
according to claim 11, wherein the polymer (B1) has: a repeating
unit which contains an acid-unstable group shown by the following
formula (3), ##STR00053## wherein R.sup.6 represents a hydrogen
atom, a methyl group, or a trifluoromethyl group, R.sup.7
individually represents a monovalent alicyclic hydrocarbon group
having 4 to 20 carbon atoms, a derivative thereof, or a linear or
branched alkyl group having 1 to 4 carbon atoms, and a repeating
unit which contains a lactone structure shown by at least one of
the following formulas (4-1) to (4-6), ##STR00054## wherein R.sup.8
represents a hydrogen atom or a substituted or unsubstituted alkyl
group having 1 to 4 carbon atoms, R.sup.9 represents a hydrogen
atom or a methoxy group, A represents a single bond or a methylene
group, B represents an oxygen atom or a methylene group, p is an
integer of 1 to 3, and m is 0 or 1.
16. The positive-working radiation-sensitive resin composition
according to claim 12, wherein the polymer (B1) has: a repeating
unit which contains an acid-unstable group shown by the following
formula (3), ##STR00055## wherein R.sup.6 represents a hydrogen
atom, a methyl group, or a trifluoromethyl group, R.sup.7
individually represents a monovalent alicyclic hydrocarbon group
having 4 to 20 carbon atoms, a derivative thereof, or a linear or
branched alkyl group having 1 to 4 carbon atoms, and a repeating
unit which contains a lactone structure shown by at least one of
the following formulas (4-1) to (4-6), ##STR00056## wherein R.sup.8
represents a hydrogen atom or a substituted or unsubstituted alkyl
group having 1 to 4 carbon atoms, R.sup.9 represents a hydrogen
atom or a methoxy group, A represents a single bond or a methylene
group, B represents an oxygen atom or a methylene group, p is an
integer of 1 to 3, and m is 0 or 1.
17. A positive-working radiation-sensitive resin composition
comprising (B2) a polymer containing a crosslinking group and an
acid-unstable group, (C) a radiation-sensitive acid generator, and
(D) a solvent, the positive-working radiation-sensitive resin
composition being used for forming a first resist layer used in a
method of forming a resist pattern which comprises: (1) a step of
forming a first resist pattern by forming a first resist layer on a
substrate using the positive-working radiation-sensitive resin
composition for forming the first resist layer, selectively
exposing the first resist layer to radiation through a mask, and
developing the exposed first resist layer, (2) a step of making the
first resist pattern inactive to radiation or insolubilizing the
first resist pattern in an alkaline developer or a positive-working
radiation-sensitive resin composition for forming a second resist
layer (3) a step of forming a second resist layer on the substrate
on which the first resist pattern has been formed using the
positive-working radiation-sensitive resin composition for forming
the second resist layer and selectively exposing the second resist
layer to radiation through a mask in the space area of the first
resist pattern, and (4) a step of forming a second resist pattern
in the space area of the first resist pattern by developing the
exposed second resist layer.
18. The positive-working radiation-sensitive resin composition
according to claim 17, wherein the polymer (B2) has: a repeating
unit which contains an acid-unstable group shown by the following
formula (3), ##STR00057## wherein R.sup.6 represents a hydrogen
atom, a methyl group, or a trifluoromethyl group, R.sup.7
individually represents a monovalent alicyclic hydrocarbon group
having 4 to 20 carbon atoms, a derivative thereof, or a linear or
branched alkyl group having 1 to 4 carbon atoms, and a repeating
unit which contains a lactone structure shown by at least one of
the following formulas (4-1) to (4-6), ##STR00058## wherein R.sup.8
represents a hydrogen atom or a substituted or unsubstituted alkyl
group having 1 to 4 carbon atoms, R.sup.9 represents a hydrogen
atom or a methoxy group, A represents a single bond or a methylene
group, B represents an oxygen atom or a methylene group, p is an
integer of 1 to 3, and m is 0 or 1.
19. The positive-working radiation-sensitive resin composition
according claim 17, wherein the polymer (B2) contains at least one
repeating unit shown by the following formulas (5-1) or (5-2),
##STR00059## wherein, R.sup.10 represents a hydrogen atom, a methyl
group, or a trifluoromethyl group, D represents a methylene group,
an ethylene group, or a propylene group; and R.sup.11 is a group
shown by the following formula (5-1-A) or the following formula
(5-1-B), ##STR00060## wherein, R.sup.10 represents a hydrogen atom,
a methyl group, or a trifluoromethyl group, R.sup.12 represents a
methylene group or an alkylene group having 2 to 6 carbon atoms,
R.sup.13 represents a hydrogen atom, a methyl group, or an ethyl
group, and n is 0 or 1.
20. The positive-working radiation-sensitive resin composition
according claim 18, wherein the polymer (B2) contains at least one
repeating unit shown by the following formulas (5-1) or (5-2),
##STR00061## wherein, R.sup.10 represents a hydrogen atom, a methyl
group, or a trifluoromethyl group, D represents a methylene group,
an ethylene group, or a propylene group; and R.sup.11 is a group
shown by the following formula (5-1-A) or the following formula
(5-1-B), ##STR00062## wherein, R.sup.10 represents a hydrogen atom,
a methyl group, or a trifluoromethyl group, R.sup.12 represents a
methylene group or an alkylene group having 2 to 6 carbon atoms,
R.sup.13 represents a hydrogen atom, a methyl group, or an ethyl
group, and n is 0 or 1.
21. The positive-working radiation-sensitive resin composition
according to claim 19, containing the repeating unit shown by the
above formulas (5-1) or (5-2) in an amount of 1 to 30 mol % of 100
mol % of the total polymer component in the positive-working
radiation-sensitive resin composition.
22. The positive-working radiation-sensitive resin composition
according to claim 20, containing the repeating unit shown by the
above formulas (5-1) or (5-2) in an amount of 1 to 30 mol % of 100
mol % of the total polymer component in the positive-working
radiation-sensitive resin composition.
23. A method for forming a pattern comprising: (1) a step of
forming a first resist pattern by forming a first resist layer on a
substrate using a positive-working radiation-sensitive resin
composition for forming the first resist layer, selectively
exposing the first resist layer to radiation through a mask, and
developing the exposed first resist layer, (2) a step of making the
first resist pattern inactive to radiation or insolubilizing the
first resist pattern in an alkaline developer or a positive-working
radiation-sensitive resin composition for forming a second resist
layer (3) a step of forming a second resist layer on the substrate
on which the first resist pattern has been formed using the
positive-working radiation-sensitive resin composition for forming
the second resist layer and selectively exposing the second resist
layer to radiation through a mask in the space area of the first
resist pattern, and (4) a step of forming a second resist pattern
in the space area of the first resist pattern by developing the
exposed second resist layer, the positive-working
radiation-sensitive resin composition for forming the first resist
layer being the composition according to claim 1.
24. A method for forming a pattern comprising: (1) a step of
forming a first resist pattern by forming a first resist layer on a
substrate using a positive-working radiation-sensitive resin
composition for forming the first resist layer, selectively
exposing the first resist layer to radiation through a mask, and
developing the exposed first resist layer, (2) a step of making the
first resist pattern inactive to radiation or insolubilizing the
first resist pattern in an alkaline developer or a positive-working
radiation-sensitive resin composition for forming a second resist
layer (3) a step of forming a second resist layer on the substrate
on which the first resist pattern has been formed using the
positive-working radiation-sensitive resin composition for forming
the second resist layer and selectively exposing the second resist
layer to radiation through a mask in the space area of the first
resist pattern, and (4) a step of forming a second resist pattern
in the space area of the first resist pattern by developing the
exposed second resist layer, the positive-working
radiation-sensitive resin composition for forming the first resist
layer being the composition according to claim 17.
25. The method for forming a pattern according to claim 23, wherein
the step of making the first resist pattern inactive to radiation
comprises making inactive to heating at a 140.degree. C. or higher
temperature or to radiation at a wavelength of not more than 300
nm.
26. The method for forming a pattern according to claim 24, wherein
the step of making the first resist pattern inactive to radiation
comprises making inactive to heating at a 140.degree. C. or higher
temperature or to radiation at a wavelength of not more than 300
nm.
Description
TECHNICAL FIELD
[0001] The present invention relates to a positive-working
radiation-sensitive resin composition and a method for forming a
resist pattern using the composition. More particularly, the
present invention relates to a method for forming a resist pattern
using a positive-working radiation-sensitive resin composition
suitably used in liquid immersion lithography in which a resist
film is exposed to radiation through a liquid for liquid immersion
lithography such as water.
BACKGROUND ART
[0002] In the field of microfabrication represented by the
manufacture of integrated circuit devices, lithographic technology
enabling microfabrication with a line width of 0.10 .mu.m or less
has been demanded in recent years in order to increase the degree
of integration. However, microfabrication in a subquarter micron
level is said to be very difficult using near ultraviolet rays such
as i-lines which are generally used as radiation in a common
lithography process. Therefore, in order to perform
microfabrication with a line width of 0.10 .mu.m or less, use of
radiation with a shorter wavelength has been studied. As examples
of such short wavelength radiation, a bright line spectrum of a
mercury lamp, deep ultraviolet rays represented by excimer lasers,
X rays, electron beams, and the like can be given. A KrF excimer
laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 193
nm) are being given particular attention.
[0003] As a resist suitable for being irradiated with such an
excimer laser, many chemically amplified resists utilizing the
chemical amplification effect of a component having an
acid-dissociable functional group and a component (hereinafter
referred to as "an acid generator") which generates an acid upon
irradiation (hereinafter referred to as "exposure") have been
proposed. As a chemically amplified resist, a resist containing a
resin having a t-butyl ester group of carboxylic acid or a t-butyl
carbonate group of phenol and an acid generator has been proposed.
The t-butyl ester group or t-butyl carbonate group in the resin
dissociates by the action of an acid generated upon exposure,
whereby the resist is provided with an acidic group such as a
carboxylic group or a phenolic hydroxyl group. As a result, the
exposed areas of the resist film become readily soluble in an
alkaline developer.
[0004] Capability of forming more minute patterns (a minute resist
pattern with a line width of about 45 nm, for example) will be
required for the lithographic process in the future. Reducing the
wavelength of a light source of a photolithography instrument and
increasing the numerical aperture (NA) of a lens could be a means
for forming such a pattern with a line width of less than 45 nm.
However, an expensive exposure machine is necessary for reducing
the wavelength of a light source. In addition, due to a trade-off
relationship between the resolution and the depth of focus,
increasing the numerical aperture (NA) of a lens involves a problem
of decreasing the depth of focus even if the resolution is
increased.
[0005] Recently, a liquid immersion lithographic method has been
reported as a lithographic technique enabling solution of such a
problem. In the process, a layer of a liquid high refractive index
medium (liquid for liquid immersion lithography) such as pure water
or a fluorine-containing inert liquid is caused to be present
during exposure between the lens and the resist film on a
substrate, at least on the surface of the resist film. According to
this method, an inert gas atmosphere in the light-path space, such
as air and nitrogen, is replaced by a liquid with a high refractive
index (n), for example, pure water, whereby resolution can be
increased without a decrease in the focal depth by using a light
source with a given wavelength to the same degree as in the case in
which a light source with a shorter wavelength is used or the case
in which a higher NA lens is used. Since a resist pattern with a
higher resolution excelling in focal depth can be formed at a low
cost using a lens mounted in existing apparatuses by using the
liquid immersion lithographic method, the method has received a
great deal of attention and is currently being put into
practice.
[0006] Although downsizing of the line width of the above exposure
technology is said to be up to 45 nmhp at most, the technological
development is advancing toward a 32 nmhp generation requiring
further minute fabrication. More recently, in an effort to respond
to such device complication and high density requirement a double
patterning or double exposure technology of patterning 32 nm LS by
producing a rough line pattern or an isolated trench pattern and
superposing these patterns displacing one pattern from the other by
half a pitch has been proposed in Non-patent Document 1 and
Non-patent Document 2.
[0007] In one proposed example, after forming a 1:3 pitch 32 nm
line and after processing a hard mask made from a material such as
SiO.sub.2 by etching, another 1:3 pitch 32 nm line is formed in a
position displaced from the first position by half a pitch,
followed by HM processing again by etching. As a result, a 1:1
pitch 32 nm line can be ultimately formed (Non-patent Document
2).
Non-patent Document 1: SPIE 2006 61531K
Non-patent Document 2: Third International Symposium Immersion
Lithography PO-11
[0008] Although several processes have been proposed, none has
disclosed a specific material which can be put into practice.
DISCLOSURE OF THE INVENTION
[0009] The present invention has been achieved in view of this
situation and has an object of providing a method for forming a
resist pattern using a specific positive-working
radiation-sensitive resin composition which can be suitably used in
liquid immersion exposure for forming the first layer in double
exposure patterning using a liquid immersion lithographic process,
wherein the first resist pattern is made inactive to radiation to
enable formation of the second layer pattern while maintaining the
first layer pattern as is and without making it soluble in alkali
when the second layer is exposed to radiation for patterning.
[0010] In order to achieve the above object, the following method
for forming a pattern using a resin composition for forming a fine
pattern is provided according to the present invention.
[1] A positive-working radiation-sensitive resin composition
comprising (A) a crosslinking agent, (B1) a polymer containing an
acid-unstable group (not containing a crosslinking group), (C) a
radiation-sensitive acid generator, and (D) a solvent, the
positive-working radiation-sensitive resin composition being used
for forming a first resist layer used in a method of forming a
resist pattern which comprises (1) a step of forming a first resist
pattern by forming a first resist layer on a substrate using the
positive-working radiation-sensitive resin composition for forming
the first resist layer, selectively exposing the first resist layer
to radiation through a mask, and developing the exposed first
resist layer, (2) a step of making the first resist pattern
inactive to radiation or insolubilizing the first resist pattern in
an alkaline developer or a positive-working radiation-sensitive
resin composition for forming a second resist layer, (3) a step of
forming a second resist layer on the substrate on which the first
resist pattern has been formed using the positive-working
radiation-sensitive resin composition for forming the second resist
layer, and selectively exposing the second resist layer to
radiation through a mask in the space area of the first resist
pattern, and (4) a step of forming a second resist pattern in the
space area of the first resist pattern by developing the exposed
second resist layer. [2] The positive-working radiation-sensitive
resin composition according to [1], wherein the crosslinking agent
(A) is a compound having two or more groups shown by the following
formula (1),
##STR00001##
wherein R.sup.1 and R.sup.2 represent a hydrogen atom or a group
shown by the following formula (2), at least one of R.sup.1 and
R.sup.2 being a group shown by the following formula (2),
##STR00002##
wherein R.sup.3 and R.sup.4 represent a hydrogen atom, an alkyl
group having 1 to 6 carbon atoms, or an alkoxyalkyl group having 1
to 6 carbon atoms, or R.sup.3 and R.sup.4 bond together to form a
ring having 2 to 10 carbon atoms, and R.sup.5 represents a hydrogen
atom or an alkyl group having 1 to 6 carbon atoms, a compound
having two or more epoxy groups or oxetane groups, or a compound
having two or more vinyl groups and a skeleton shown by any one of
the following formulas (12-1) to (12-4),
##STR00003##
[3] The positive-working radiation-sensitive resin composition
according to [1] or [2], wherein the amount of the crosslinking
agent (A) is 1 to 30 mass % of the solid component of the
composition. [4] The positive-working radiation-sensitive resin
composition according to any one of [1] to [3], wherein the polymer
(B1) has a repeating unit which contains an acid-unstable group
shown by the following formula (3),
##STR00004##
wherein R.sup.6 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, R.sup.7 individually represents a monovalent
alicyclic hydrocarbon group having 4 to 20 carbon atoms, a
derivative thereof, or a linear or branched alkyl group having 1 to
4 carbon atoms, and a repeating unit which contains a lactone
structure shown by at least one of the following formulas (4-1) to
(4-6),
##STR00005##
wherein R.sup.8 represents a hydrogen atom or a substituted or
unsubstituted alkyl group having 1 to 4 carbon atoms, R.sup.9
represents a hydrogen atom or a methoxy group, A represents a
single bond or a methylene group, B represents an oxygen atom or a
methylene group, p is an integer of 1 to 3, and m is 0 or 1. [5] A
positive-working radiation-sensitive resin composition comprising
(B2) a polymer containing a crosslinking group and an acid-unstable
group, (C) a radiation-sensitive acid generator, and (D) a solvent,
the positive-working radiation-sensitive resin composition being
used for forming a first resist layer used in a method of forming a
resist pattern which comprises (1) a step of forming a first resist
pattern by forming a first resist layer on a substrate using the
positive-working radiation-sensitive resin composition for forming
the first resist layer, selectively exposing the first resist layer
to radiation through a mask, and developing the exposed first
resist layer, (2) a step of making the first resist pattern
inactive to radiation or insolubilizing the first resist pattern in
an alkaline developer or a positive-working radiation-sensitive
resin composition for forming a second resist layer (3) a step of
forming a second resist layer on the substrate on which the first
resist pattern has been formed using the positive-working
radiation-sensitive resin composition for forming the second resist
layer and selectively exposing the second resist layer to radiation
through a mask in the space area of the first resist pattern, and
(4) a step of forming a second resist pattern in the space area of
the first resist pattern by developing the exposed second resist
layer. [6] The positive-working radiation-sensitive resin
composition according to [5], wherein the polymer (B2) has a
repeating unit which contains an acid-unstable group shown by the
following formula (3),
##STR00006##
wherein R.sup.6 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, R.sup.7 individually represents a monovalent
alicyclic hydrocarbon group having 4 to 20 carbon atoms, a
derivative thereof, or a linear or branched alkyl group having 1 to
4 carbon atoms, and a repeating unit which contains a lactone
structure shown by at least one of the following formulas (4-1) to
(4-6),
##STR00007##
wherein R.sup.8 represents a hydrogen atom or a substituted or
unsubstituted alkyl group having 1 to 4 carbon atoms, R.sup.9
represents a hydrogen atom or a methoxy group, A represents a
single bond or a methylene group, B represents an oxygen atom or a
methylene group, p is an integer of 1 to 3, and in is 0 or 1. [7]
The positive-working radiation-sensitive resin composition
according [5] or [6], wherein the polymer (B2) contains at least
one repeating unit shown by the following formulas (5-1) or
(5-2),
##STR00008##
wherein, R.sup.10 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, D represents a methylene group, an ethylene
group, or a propylene group; and R.sup.11 is a group shown by the
following formula (5-1-A) or the following formula (5-1-B)
##STR00009##
wherein, R.sup.10 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, R.sup.12 represents a methylene group or an
alkylene group having 2 to 6 carbon atoms, R.sup.13 represents a
hydrogen atom, a methyl group, or an ethyl group, and n is 0 or 1.
[8] The positive-working radiation-sensitive resin composition
according to [7], containing the repeating unit shown by the above
formulas (5-1) or (5-2) in an amount of 1 to 30 mol % of 100 mol %
of the total polymer component in the positive-working
radiation-sensitive resin composition. [9] A method for forming a
pattern comprising (1) a step of forming a first resist pattern by
forming a first resist layer on a substrate using a
positive-working radiation-sensitive resin composition for forming
the first resist layer, selectively exposing the first resist layer
to radiation through a mask, and developing the exposed first
resist layer, (2) a step of making the first resist pattern
inactive to radiation or insolubilizing the first resist pattern in
an alkaline developer or a positive-working radiation-sensitive
resin composition for forming a second resist layer (3) a step of
forming a second resist layer on the substrate on which the first
resist pattern has been formed using the positive-working
radiation-sensitive resin composition for forming the second resist
layer and selectively exposing the second resist layer to radiation
through a mask in the space area of the first resist pattern, and
(4) a step of forming a second resist pattern in the space area of
the first resist pattern by developing the exposed second resist
layer, the positive-working radiation-sensitive resin composition
for forming the first resist layer being the composition according
to any one of [1] to [8]. [10] The method for forming a pattern
according to [9], wherein the step of making the first resist
pattern inactive to radiation comprises making inactive to heating
at a 140.degree. C. or higher temperature or to radiation at a
wavelength of not more than 300 nm.
[0011] According to the resist pattern forming method of the
present invention, in a double exposure patterning using a
radiation-sensitive resin composition containing a crosslinking
agent and the first layer resist pattern is made inactive to
radiation, the second layer pattern can be formed while maintaining
the first layer pattern as is without making it soluble in alkali
when the second layer is exposed to radiation for patterning.
[0012] Therefore, the composition can be suitably used for
manufacturing semiconductor devices, which are expected to become
more and more micronized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view for illustrating the steps of
forming a resist pattern.
[0014] FIG. 2 is a schematic view for illustrating the steps of
forming a resist pattern.
[0015] FIG. 3 is a schematic view for illustrating the steps of
forming a resist pattern.
[0016] FIG. 4 is a diagrammatic chart showing the correlation of
the exposure dose and the film thickness.
EXPLANATION OF SYMBOLS
[0017] 1: substrate, 2: first resist layer, 21: pattern latent
image part, 22: first resist pattern, 23: inactivated first resist
pattern, 3: liquid for liquid immersion lithographic process, 4:
mask, 5: second resist layer, 51: pattern latent image part, 52:
second resist pattern, 6: liquid for liquid immersion lithographic
process, 7: mask
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] The present invention will now be described in detail.
[1] Method of Forming Resist Pattern
[0019] The resist pattern forming method of the present invention
comprises the following steps (1) to (4):
Step (1): a step of forming a first resist layer on a substrate
using a positive-working radiation-sensitive resin composition for
forming the first resist layer (hereinafter referred to from time
to time as "first resist layer-forming resin composition"),
exposing a prescribed area of the first resist layer to radiation,
and developing the exposed resist layer to form a first resist
pattern. Step (2): a step of making the first resist pattern
inactive to radiation. Step (3): a step of forming a second resist
layer on a substrate on which the first resin pattern has been
formed using a positive-working radiation-sensitive resin
composition for forming the second resist layer (hereinafter
referred to from time to time as "second resist layer-forming resin
composition") and exposing a prescribed area of the second resist
layer to radiation. Step (4): a step of developing the second
resist layer to form a second resist pattern in the space area of
the first resist pattern.
[0020] The first resist layer forming resin composition and the
second resist layer forming resin composition used in the pattern
forming method of the present invention are both of the type in
which an acid-dissociable group in the resin dissociates by the
action of an acid which is generated from the acid generating
component upon exposure to radiation to form a carboxylic group
and, as a result, solubility of the exposed part of the resist in
an alkaline developer increases, whereby the exposed part is
dissolved in an alkaline developer and removed to provide a
positive-working resist pattern. The details of the components and
the like contained in the resin composition will be described
later.
[0021] In the step (1), the first resist layer is formed by
applying the first resist layer forming resin composition to a
substrate such as a silicon wafer, a wafer coated with aluminum, or
the like using an appropriate application method such as rotational
coating, cast coating, and roll coating. Although not particularly
limited, the thickness of the first resist layer is usually 10 to
1000 nm, and preferably 10 to 500 nm.
[0022] After applying the first resist layer forming resin
composition, the coating may be optionally prebaked (PB) to
vaporize the solvent. The heating temperature for the PB is usually
about 30 to 200.degree. C., and preferably about 50 to 150.degree.
C., although the heating conditions are changed according to the
composition of the resin composition.
[0023] In the step (1), a selected area on the first resist layer
thus formed is exposed to radiation through a mask with a
predetermined pattern, optionally, via a liquid for liquid
immersion lithography such as water or a fluorine-containing inert
liquid, and exposed to radiation to form a pattern latent image
part (part made insoluble in alkali by exposure) on the first
resist layer.
[0024] As radiation used for exposure, visible rays, ultraviolet
rays, deep ultraviolet rays, X-rays, charged particle beams, or the
like are appropriately selected depending on the types of the acid
generator contained in the resin composition. It is preferable to
use a deep ultraviolet ray represented by an ArF excimer laser
(wavelength: 193 nm) or a KrF excimer laser (wavelength: 248 nm).
An ArF excimer laser (wavelength: 193 nm) is particularly
preferable.
[0025] The exposure conditions such as a radiation dose are
appropriately determined depending on the composition, the type of
additives, and the like of the first resist layer forming resin
composition.
[0026] In the present invention, it is preferable to perform
post-exposure bake (PEB) after the exposure. The PEB ensures a
smooth dissociation reaction of the acid-dissociable group
contained in the resin components. The heating temperature for the
PEB is usually 30 to 200.degree. C., and preferably 50 to
170.degree. C., although the heating conditions are changed
according to the composition of the resin composition.
[0027] In the step (1), the exposed first resist layer is developed
to cause the pattern latent image part to be exposed, thereby
forming a positive-working first resist pattern.
[0028] As examples of the developer used for development, alkaline
aqueous solutions prepared by dissolving at least one of alkaline
compounds such as sodium hydroxide, potassium hydroxide, sodium
carbonate, sodium silicate, sodium metasilicate, aqueous ammonia,
ethylamine, n-propylamine, diethylamine, di-n-propylamine,
triethylamine, methyldiethylamine, ethyldimethylamine,
triethanolamine, tetramethylammonium hydroxide, pyrrole,
piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and
1,5-diazabicyclo-[4.3.0]-5-nonene are preferable.
[0029] The concentration of the alkaline aqueous solution is
usually 10 mass % or less. If the concentration of the alkaline
aqueous solution exceeds 10 mass %, an unexposed part may be
dissolved in the developer.
[0030] Organic solvents may be added to the developer containing an
alkaline aqueous solution. As examples of the organic solvent,
ketones such as acetone, methyl ethyl ketone, methyl i-butyl
ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and
2,6-dimethylcyclohexanone; alcohols such as methylalcohol,
ethylalcohol, n-propylalcohol, i-propylalcohol, n-butylalcohol,
t-butylalcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, and
1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane;
esters such as ethyl acetate, n-butyl acetate, and i-amyl acetate;
aromatic hydrocarbons such as toluene and xylene; phenol,
acetonylacetone, dimethylformamide; and the like can be given.
These organic solvents may be used either individually or in
combination of two or more.
[0031] The amount of the organic solvent to be used is preferably
100 vol % or less of the alkaline aqueous solution. An amount of
the organic solvent exceeding 100 vol % may decrease
developability, giving rise to a larger undeveloped portion in the
exposed area. In addition, an appropriate amount of a surfactant
and the like may be added to the developer containing the alkaline
aqueous solution.
[0032] After development using the alkaline aqueous solution
developer, the resist film is generally washed with water and
dried.
[0033] In order to bring out the potential of the resin composition
to the maximum extent, an organic or inorganic antireflection film
may be formed on the substrate as disclosed in JP-B-6-12452
(JP-A-59-93448), for example. A protective film may be provided on
the photoresist film in order to prevent an adverse effect of basic
impurities and the like that are present in the environmental
atmosphere using a method described in, for example, JP-A-5-188598.
Moreover, in order to prevent the acid generator and the like from
flowing out of the photoresist film, a protective film for liquid
immersion lithography may be provided on the photoresist film as
disclosed in, for example, JP-A-2005-352384. These techniques may
be used in combination.
[0034] In the step (2) an inactivating treatment which makes the
first resist pattern inactive to radiation is carried out. The term
"inactive to radiation" used in the present invention refers to the
properties of the resin components not being sensitized by exposure
to radiation. That is, the inactivated pattern does not become
soluble in alkali even if exposed to radiation.
[0035] As examples of the inactivation treatment, exposure to
radiation, heating, UV curing, and the like can be given.
[0036] As a specific method of exposure to radiation, a method of
exposing the first resist pattern to radiation at a dose of 2 to 20
times the optimum dose of the first resist pattern formation can be
given, for example.
[0037] As a specific example of the method of the heating
treatment, a method of heating at a temperature higher than the PEB
temperature applied when forming the first resist pattern can be
given.
[0038] As a specific method of UV curing, a method of using a lamp
such as an Are lamp, a KrCl lamp, a Kr.sub.2 lamp, an XeCl lamp,
and an Xe.sub.2 lamp (manufactured by USHIO, INC.) can be
given.
[0039] These inactivation methods may be used either individually
or in combination of two or more.
[0040] In the step (3), the second resist layer is formed by
applying the second resist layer forming resin composition to the
substrate on which the first resist pattern has been formed using
an appropriate application method such as rotational coating, cast
coating, and roll coating. With regard to the positive-working
radiation-sensitive resin composition containing a crosslinking
agent of the present invention, because the components insoluble in
the solvent used for the second resist layer forming resin
composition are used as the components for the polymer (B1) of the
first resist layer forming resin composition, the second resist
layer can be formed without causing mixing with the first resist
pattern. With regard to the positive-working radiation-sensitive
resin composition in which the polymer (B2) containing a
crosslinking agent and an acid-unstable group are used, since such
a resin composition is inactivated with heat, the second resist
layer can be formed without causing mixing with the first resist
pattern, and either the solvents used for the first resist layer
forming resin composition and the second resist layer forming resin
composition are the same or different.
[0041] Although not particularly limited, the thickness of the
second resist layer is usually 10 to 1000 nm, and preferably 10 to
500 nm.
[0042] After applying the second resist layer forming resin
composition, the coating may be optionally prebaked (PB) to
vaporize the solvent. The heating temperature for the PB is usually
about 30 to 200.degree. C., and preferably 50 to 150.degree. C.,
although the heating conditions are changed according to the
composition of the resin composition.
[0043] In the step (3), a selected area on the second resist layer
thus formed is exposed to radiation through a mask with a
predetermined pattern, optionally, via a liquid for liquid
immersion lithography such as water or a fluorine-containing inert
liquid, and exposed to radiation to form a pattern latent image
part (part made insoluble in alkali by exposure) in the second
resist layer.
[0044] In the step (4), the exposed second resist layer is
developed to cause the pattern latent image part to be exposed,
thereby forming a positive-working second resist pattern in the
space area of the first resist pattern.
[0045] The space area of the first resist pattern indicates the
area from which the resist coating has been removed by being
dissolved during development.
[0046] The developing method is the same as the developing method
of the step (1).
[0047] A specific example of the pattern forming method comprising
the above steps (1), (2), (3), and (4) using a positive-working
radiation-sensitive resin composition containing a crosslinking
agent (A) will be explained referring to FIG. 1.
[0048] As shown in FIG. 1(a), in the step (1), a pattern latent
image part 21 is formed in the first resist layer 2 formed on a
substrate 1 using a first resist layer forming resin composition by
exposing the desired area of the first resist layer 2 to radiation
(see the arrows in the Figure) through a mask 4 with a specified
pattern, optionally via a liquid 3 for liquid immersion lithography
such as water. The exposed resist is then developed to form a first
resist pattern 22 (1L3S) on the substrate 1 as shown in FIG.
1(b).
[0049] Next, in the step (2), the first resist pattern 22 is
exposed to radiation as shown in FIG. 1(c) (see the arrows in the
Figure), whereby the first resist pattern 22 is changed into an
inactivated pattern 23 which is inactive to radiation.
[0050] After that, in the step (3), a pattern latent image part 51
is formed in the second resist layer 5 formed on the substrate 1 on
which a first resist pattern 23 has been formed using a second
positive-working radiation-sensitive resin composition by exposing
the desired area of the second resist layer 5 to radiation (see the
arrows in the Figure) through a mask 7 with a specified pattern,
optionally via a liquid 6 for liquid immersion lithography such as
water, as shown in FIG. 1(d).
[0051] Next, in the step (4), the exposed area is developed to form
a second resist pattern 52 on the space part of the inactivated
first resist pattern 23, whereby a 1L1S resist pattern with the
first resist pattern 23 and the second resist pattern 52 being
alternately arranged on the substrate 1, as shown in FIG. 1(e), is
formed.
[0052] The resist pattern forming method of the present invention
may have the following step (2') instead of the above steps (2) and
(3), in which case, the method of the present invention may
comprises the above step (1), the following step (2'), and the
above step (4).
Step (2'): a step of forming a second resist layer on a substrate
on which the first resist layer has been formed using a the second
resist layer-forming resin composition and exposing prescribed
areas of the second resist layer and the above first resist layer
to radiation, to inactivate the first resist pattern to radiation
and, at the same time, to form the pattern latent image part in the
second resist layer.
[0053] In the step (2'), the second resist layer forming resin
composition is applied onto the substrate on which the first resist
pattern has been formed, whereby the second resist layer is formed.
The thickness of the second resist layer is the same as described.
After applying the second resist layer forming resin composition,
the coating may be optionally prebaked (PB) to vaporize the
solvent. The prebaking conditions are the same as mentioned
above.
[0054] Next, selected areas of the formed second resist layer and
the above-mentioned first resist pattern are exposed to radiation
through a mask with a predetermined pattern, optionally, via a
liquid for liquid immersion lithography such as water or a
fluorine-containing inert liquid, and exposed to radiation. In this
instance, a pattern latent image part (part made insoluble in
alkali by exposure) is formed on the second resist layer and, at
the same time, the first resist pattern is inactivated. Therefore,
when step (2') is performed, it is not necessary to perform an
inactivation step by exposure. Since the number of exposure
operations can be reduced in this manner, this method is
economical.
[0055] The dose of radiation in the step (2') is 2 to 10 times the
optimum dose applied for forming the first resist pattern and
preferably the same as the optimum dose applied for forming the
second resist pattern.
[0056] A specific example of the pattern forming method comprising
the above steps (1), (2'), and (4) will be explained referring to
FIG. 2.
[0057] As shown in FIG. 2(a), in the step (1), a pattern latent
image part 21 is formed in the first resist layer 2 formed on a
substrate 1 using the first resist layer forming resin composition
by exposing the desired area of the first resist layer 2 to
radiation (see arrows in the Figure) through a mask 4 with a
specified pattern, optionally via a liquid 3 for liquid immersion
lithography such as water. The exposed resist is then developed to
form a first resist pattern 22 (1L3S) on the substrate 1 as shown
in FIG. 2(b).
[0058] After that, in the above step (2'), desired areas of the
second resist layer 5 formed on the substrate 1 on which a first
resist pattern 22 has been formed using a second resist layer
forming resin composition and the first resist pattern 22 are
exposed to radiation (see the arrows in the Figure) through a mask
7 with a specified pattern, optionally via a liquid 6 for liquid
immersion lithography such as water, as shown in FIG. 2(c), whereby
a pattern latent image part 51 is formed in the second resist layer
5 and, at the same time, the first resist pattern 22 is
inactivated.
[0059] Next, in the step (4), the exposed area is developed to form
a second resist pattern 52 on the space part of the inactivated
first resist pattern 23, whereby a 1L1S resist pattern with the
first resist pattern 23 and the second resist pattern 52 being
alternately arranged on the substrate 1, as shown in FIG. 2(d), is
formed.
[0060] A specific example of the pattern forming method of the
present invention comprising the above steps (1), (2), (3), and (4)
using a positive-working radiation-sensitive resin composition in
which the polymer (B2) containing a crosslinking group and an
acid-unstable group is used will be explained referring to FIG.
3.
[0061] As shown in FIG. 3(a), in the step (1), a pattern latent
image part 21 is formed in the first resist layer 2 formed on a
substrate 1 using a first resist layer forming resin composition by
exposing the desired area of the first resist layer 2 to radiation
(see arrows in the Figure) through a mask 4 with a specified
pattern, optionally via a liquid 3 for liquid immersion lithography
such as water. The exposed resist is then developed to form a first
resist pattern 22 (1L3S) on the substrate 1 as shown in FIG.
3(b).
[0062] Next, in the step (2), as shown in FIG. 3(c), the first
resist pattern 22 is baked at a temperature of 120.degree. C. or
more, and preferably 140.degree. C. or more to change the first
resist pattern 22 into an inactivated pattern 23 which is inactive
to radiation.
[0063] After that, in the step (3), a pattern latent image part 51
is formed in the second resist layer 5 formed on the substrate 1 on
which a first resist pattern 23 has been formed using a second
resist layer forming resin composition by exposing the desired area
of the second resist layer 5 to radiation (see the arrows in the
Figure) through a mask 7 with a specified pattern, optionally via a
liquid 6 for liquid immersion lithography such as water, as shown
in FIG. 3(d).
[0064] Next, in the step (4), the exposed area is developed to form
a second resist pattern 52 on the space part of the inactivated
first resist pattern 23, whereby a 1L1S resist pattern with the
first resist pattern 23 and the second resist pattern 52 being
alternately arranged on the substrate 1, as shown in FIG. 3(e), is
formed.
[2] Positive-working radiation-sensitive resin composition for
forming first resist layer
[0065] When a positive-working radiation-sensitive resin
composition containing a crosslinking agent (A) is used, the first
resist layer forming resin composition of the present invention
comprises the crosslinking agent (A), a resin containing an
acid-unstable group, a radiation-sensitive acid generator (C), and
a solvent (D). This resin composition exhibits both a
positive-working response and a negative-working response to a
certain amount of radiation. Specifically, on the low exposure dose
side, the solubility increase of the composition due to the action
of an acid is more than the solubility decrease due to the action
of the crosslinking agent, whereby the composition exhibits a
positive-working response, whereas on the high exposure dose side,
the solubility decrease due to the action of the crosslinking agent
is more than the solubility increase of the composition due to the
action of an acid, whereby the composition exhibits a
negative-working response. The relationship between the exposure
dose and resist film thickness is as shown in FIG. 4.
[0066] When using the positive-working radiation-sensitive resin
composition in which the polymer (B2) containing a crosslinking
group and an acid-unstable group is used, the first resist layer
formed from the composition containing the polymer (B2) containing
a crosslinking group and an acid-unstable group, the
radiation-sensitive acid generator (C), and the solvent (D) is
provided with increased resistance to the second resist layer by
being baked at a temperature of 140.degree. C. or more and can thus
remain without being damaged when forming the second resist.
< Crosslinking Agent (A)>
[0067] The crosslinking component used in the present invention is
a compound having the group shown by the following formula (1)
(hereinafter referred to as "crosslinking component I"),
##STR00010##
wherein R.sup.1 and R.sup.2 represent a hydrogen atom or a group
shown by the following formula (2), at least one of R.sup.1 and
R.sup.2 being a group shown by the following formula (2),
##STR00011##
wherein R.sup.3 and R.sup.4 represent a hydrogen atom, an alkyl
group having 1 to 6 carbon atoms, or an alkoxyalkyl group having 1
to 6 carbon atoms, or R.sup.3 and R.sup.4 bond together to form a
ring having 2 to 10 carbon atoms, and R.sup.5 represents a hydrogen
atom or an alkyl group having 1 to 6 carbon atoms, a compound
having two or more epoxy groups or oxetane groups (hereinafter
referred to as "crosslinking component II"), or a compound having
two or more vinyl groups and a skeleton shown by any one of the
following formulas (12-1) to (12-4) (hereinafter referred to as
"crosslinking component III"),
##STR00012##
or a mixture of the crosslinking component I, the crosslinking
component II, and the crosslinking component III.
[0068] The above-mentioned crosslinking components act as a
crosslinking component (curing component) with which the resin
containing a hydroxyl group mentioned above and/or the crosslinking
components mutually react with the action of an acid.
[0069] As specific examples of the compound shown by the formula I
(the crosslinking component I), nitrogen-containing compounds
prepared by alkyl-ethrification of all or a part of active methylol
groups of a compound such as (poly)methylolized melamine,
(poly)methylolized glycoluril, (poly)methylolized benzoguanamine,
(poly)methylolized urea, and the like can be given. As examples of
the alkyl group, a methyl group, ethyl group, butyl group, or a
mixture of these groups can be given, and may include an oligomer
component which is made by partly self condensation. As specific
examples, hexamethoxymethylated melamine, hexabutoxymethylated
melamine, tetramethoxymethylated glycoluril, tetrabutoxymethylated
glycoluril, and the like can be given.
[0070] As commercially available compounds, Cymel 300, Cymel 301,
Cymel 303, Cymel 350, Cymel 232, Cymel 235, Cymel 236, Cymel 238,
Cymel 266, Cymel 267, Cymel 285, Cymel 1123, Cymel 1123-10, Cymel
1170, Cymel 370, Cymel 771, Cymel 272, Cymel 1172, Cymel 325, Cymel
327, Cymel 703, Cymel 712, Cymel 254, Cymel 253, Cymel 212, Cymel
1128, Cymel 701, Cymel 202, and Cymel 207 (manufactured by Nihon
Cytec Industries, Inc.), Nikalac MW-30M, Nikalac MW-30, Nikalac
MW-22, Nikalac MW-24X, Nikalac MS-21, Nikalac MS-11, Nikalac
MS-001, Nikalac MX-002, Nikalac MX-730, Nikalac MX-750, Nikalac
MX-708, Nikalac MX-706, Nikalac MX-042, Nikalac MX-035, Nikalac
MX-45, Nikalac MX-410, Nikalac MX-302, Nikalac MX-202, Nikalac
SM-651, Nikalac SM-652, Nikalac SM-653, Nikalac SM-551, Nikalac
SM-451, Nikalac SB-401, Nikalac SB-355, Nikalac SB-303, Nikalac
SB-301, Nikalac SB-255, Nikalac SB-203, Nikalac SB-201, Nikalac
BX-4000, Nikalac BX-37, Nikalac BX-55H, and Nikalac BL-60
(manufactured by Sanwa Chemical Co., Ltd.), and the like can be
given. Cymel 325, Cymel 327, Cymel 703, Cymel 712, Cymel 254, Cymel
253, Cymel 212, Cymel 1128, Cymel 701, Cymel 202, and Cymel 207
which are the compounds of the formula (1) in which either R.sup.1
or R.sup.2 is a hydrogen atom, that is, crosslinking components
having an imino group, are preferable.
[0071] As examples of the crosslinking component II which contains
two or more epoxy groups or oxetane groups as reactive groups,
epoxy cyclohexyl group-containing compounds such as
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate,
2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-m-dioxane,
bis(3,4-epoxycyclohexylmethyl)adipate,
bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate,
3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate,
methylenebis(3,4-epoxycyclohexane), ethylene glycol
di(3,4-epoxycyclohexylmethyl)ether,
ethylenebis(3,4-epoxycyclohexanecarboxylate),
.epsilon.-caprolactone-modified
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate,
trimethylcaprolactone-modified
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, and
.beta.-methyl-.delta.-valerolactone-modified
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate;
bisphenol A diglycidyl ether, bisphenol F diglycidyl ether,
bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl
ether, brominated bisphenol F diglycidyl ether, brominated
bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl
ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated
bisphenol S diglycidyl ether, 1,4-butanediol diglycidyl ether,
1,6-hexanediol diglycidyl ether, glycerol triglycidyl ether,
trimethylolpropane triglycidyl ether, polyethylene glycol
diglycidyl ether, polypropylene glycol diglycidyl ethers;
polydiglycidyl ethers of polyether polyol obtained by adding one or
more alkylene oxides to an aliphatic polyhydric alcohol such as
ethylene glycol, propylene glycol, and glycerol; diglycidyl esters
of an aliphatic long-chain dibasic acid; mono-diglycidyl ethers of
aliphatic higher alcohol; phenol, cresol, butyl phenol, or
mono-glycidyl ethers of polyether alcohol obtained by adding an
alkylene oxide to these; glycidyl esters of a higher fatty acid,
oxetane compounds having two or more oxetane rings in the molecule
such as 3,7-bis(3-oxetanyl)-5-oxa-nonane,
3,3'-(1,3-(2-methylenyl)propanediylbis(oxymethylene))bis-(3-ethyloxetane)-
, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene,
1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane,
1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol
bis(3-ethyl-3-oxetanylmethyl)ether, dicyclopentenyl
bis(3-ethyl-3-oxetanylmethyl)ether, triethylene glycol
bis(3-ethyl-3-oxetanylmethyl)ether, tetraethylene glycol
bis(3-ethyl-3-oxetanylmethyl)ether,
tricyclodecanediyldimethylene(3-ethyl-3-oxetanylmethyl)ether,
trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether,
1,4-bis(3-ethyl-3-oxetanylmethoxy)butane,
1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, pentaerythritol
tris(3-ethyl-3-oxetanylmethyl)ether, pentaerythritol
tetrakis(3-ethyl-3-oxetanylmethyl)ether, polyethylene glycol
bis(3-ethyl-3-oxetanylmethyl)ether, dipentaerythritol
hexakis(3-ethyl-3-oxetanylmethyl)ether, dipentaerythritol
pentakis(3-ethyl-3-oxetanylmethyl)ether, dipentaerythritol
tetrakis(3-ethyl-3-oxetanylmethyl)ether, caprolactone-modified
dipentaerythritol hexakis(3-ethyl-3-oxetanylmethyl)ether,
caprolactone-modified dipentaerythritol
pentakis(3-ethyl-3-oxetanylmethyl)ether, ditrimethylolpropane
tetrakis(3-ethyl-3-oxetanylmethyl)ether, ethylene oxide
(EO)-modified bisphenol A bis(3-ethyl-3-oxetanylmethyl)ether,
propylene oxide (PO)-modified bisphenol A
bis(3-ethyl-3-oxetanylmethyl)ether, EO-modified hydrogenated
bisphenol A bis(3-ethyl-3-oxetanylmethyl)ether, PO-modified
hydrogenated bisphenol A bis(3-ethyl-3-oxetanylmethyl)ether,
EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl)ether, and the
like can be given. As examples of commercially available products
among the specific examples of the crosslinking component II,
ARONOXETANE OXT-101, OXT-121, and OXT-221 (manufactured by Toagosei
Chemical Co., Ltd.), OXTP, OXBP, and OXIPA (manufactured by Ube
Industries, Ltd.), and the like can be given.
[0072] Of these, 1,6-hexanediol diglycidyl ether and
dipentaerythritol hexakis(3-ethyl-3-oxetanylmethyl)ether are
preferable as the crosslinking component II.
[0073] As examples of the compound of the crosslinking component
III having two or more vinyl groups as reactive groups and
containing at least one of the groups shown by the formulas (12-1)
to (12-4), 1,3,5-triacryloylhexahydro-1,3,5-triazine,
triallyl-1,3,5-benzenetricarboxylate,
2,4,6-triallyloxy-1,3,5-triazine, and
1,3,5-triallyl-1,3,5-triazine-2,4,6(1H, 3H, 5H)-trione can be
given.
[0074] Of these, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H, 3H,
5H)-trione is preferable as the crosslinking component III.
[0075] The amount of the crosslinking agents in the present
invention is 1 to 30 parts by mass, and preferably 2 to 25 parts by
mass for 100 parts by mass of the resin. If less than 1 part by
mass, the degree of inactivation to radiation is insufficient,
which may result in an impaired pattern. If more than 30 parts by
mass, the pattern may not be resolved.
<Resin (B) Containing Acid-Unstable Group>
[0076] Although not particularly limited, in order for the
radiation-sensitive resin composition to exhibit the effect of the
crosslinking agent (A), the resin (B) containing an acid-unstable
group (hereinafter referred to as "resin (B)") is preferably
insoluble or scarcely soluble in alkali, but becomes soluble in
alkali by the action of an acid in an environment in which a
radiation dose is small, and is made inactive to radiation by the
action of the crosslinking agent (A) in an environment in which a
radiation dose is large. The term "alkali-insoluble" or "scarcely
alkali-soluble" refers to properties in which 50% or more of the
initial thickness of the resist film remains after development, in
the case of developing a film using only the resin (B) instead of a
resist film under alkaline development conditions employed when
forming a resist pattern of the resist film formed from the first
resist layer forming resin composition containing the resin
(B).
[0077] The resin (B) preferably has a repeating unit which contains
an acid-unstable group shown by the following formula (3) and a
repeating unit which contains a lactone structure shown by at least
one of the following formulas (4-1) to (4-6),
##STR00013## ##STR00014##
wherein R.sup.6 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, and R.sup.7 individually represents a
monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms,
a derivative thereof, or a linear or branched alkyl group having 1
to 4 carbon atoms.
[0078] As examples of the monovalent alicyclic hydrocarbon group
having 4 to 20 carbon atoms represented by R.sup.7 in the formula
(3), groups containing an alicyclic ring derived from norbornane,
tricyclodecane, tetracyclododecane, or adamantane, or cycloalkanes
such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and
cyclooctane; groups in which the above group containing an
alicyclic ring is substituted with at least one of cyclic,
branched, or linear alkyl groups having 1 to 4 carbon atoms such as
a methyl group, an ethyl group, an n-propyl group, an i-propyl
group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl
group, and a t-butyl group; and the like can be given. Any two
groups represented by R.sup.7 may form a divalent alicyclic
hydrocarbon group or a derivative thereof in combination with the
carbon atom to which these two groups bond. Of these alicyclic
hydrocarbon groups, an alicyclic ring derived from norbornane,
tricyclodecane, tetracyclododecane, adamantane, cyclopentane, or
cyclohexane, a group in which such an alicyclic ring is substituted
with any one of the above alkyl groups, and the like are
preferable.
[0079] As examples of the linear or branched alkyl group having 1
to 4 carbon atoms represented by R.sup.7 in the formula (3), a
methyl group, an ethyl group, an n-propyl group, an i-propyl group,
an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group,
and a t-butyl group can be given.
[0080] As preferable examples of --C(R.sup.7).sub.3 in the formula
(3), a t-butyl group, a 1-n-(1-ethyl-1-methyl)propyl group, a
1-n-(1,1-dimethyl)propyl group, a 1-n-(1,1-dimethyl)butyl group, a
1-n-(1,1-dimethyl)pentyl group, 1-(1,1-diethyl)propyl group, a
1-n-(1,1-diethyl)butyl group, a 1-n-(1,1-diethyl)pentyl group, a
1-(1-methyl)cyclopentyl group, a 1-(1-ethyl)cyclopentyl group, a
1-(1-n-propyl)cyclopentyl group, a 1-(1-1-propyl)cyclopentyl group,
a 1-(1-methyl)cyclohexyl group, a 1-(1-ethyl)cyclohexyl group, a
1-(1-n-propyl)cyclohexyl group, a 1-(1-1-propyl)cyclohexyl group, a
1-{1-methyl-1-(2-norbornyl)}ethyl group, a
1-{1-methyl-1-(2-tetracyclodecanyl)}ethyl group, a
1-{1-methyl-1-(1-adamantyl)}ethyl group, a 2-(2-methyl)norbornyl
group, a 2-(2-ethyl)norbornyl group, a 2-(2-n-propyl)norbornyl
group, a 2-(2-i-propyl)norbornyl group, a
2-(2-methyl)tetracyclodecanyl group, a 2-(2-ethyl)tetracyclodecanyl
group, a 2-(2-n-propyl)tetracyclodecanyl group, a
2-(2-1-propyl)tetracyclodecanyl group, a 1-(1-methyl)adamantyl
group, a 1-(1-ethyl)adamantyl group, a 1-(1-n-propyl)adamantyl
group, and a 1-(1-1-propyl)adamantyl group; groups in which these
groups are substituted by one or more cyclic, branched, or linear
alkyl groups having 1 to 4 carbon atoms such as a methyl group, an
ethyl group, a n-propyl group, an i-propyl group, an n-butyl group,
a 2-methylpropyl group, a 1-methylpropyl group, and a t-butyl
group; and the like can be given.
[0081] As preferable examples of the monomer providing the
repeating unit (3), 2-methyladamantyl-2-yl(meth)acrylate,
2-methyl-3-hydroxyadamantyl-2-yl (meth)acrylate,
2-ethyladamantyl-2-yl(meth)acrylate,
2-ethyl-3-hydroxyadamantyl-2-yl (meth)acrylate,
2-n-propyladamantyl-2-yl(meth)acrylate, 2-isopropyladamantyl-2-yl
(meth)acrylate, 2-methylbicyclo[2.2.1]hept-2-yl(meth)acrylate,
2-ethylbicyclo[2.2.1]hept-2-yl(meth)acrylate,
8-methyltricyclo[5.2.1.0.sup.2,6]decan-8-yl (meth)acrylate,
8-ethyltricyclo[5.2.1.0.sup.2,6]decan-8-yl(meth)acrylate,
4-methyltetracyclo[6.2.1.sup.3,6.0.sup.2,7]dodecan-4-yl(meth)acrylate,
4-ethyltetracyclo[6.2.1.sup.3,6.0.sup.2,7]dodecan-4-yl(meth)acrylate,
1-(bicyclo[2.2.1]hept-2-yl)-1-methylethyl(meth)acrylate,
1-(tricyclo[5.2.1.0.sup.2,6]decan-8-yl)-1-methylethyl(meth)acrylate,
1-(tetracyclo[6.2.1.sup.3,6.0.sup.2,7]dodecan-4-yl)-1-methylethyl(meth)ac-
rylate, (adamantan-1-yl)-1-methylethyl(meth)acrylate,
1-(3-hydroxyadamantan-1-yl)-1-methylethyl(meth)acrylate,
1,1-dicyclohexylethyl (meth)acrylate,
1,1-di(bicyclo[2.2.1]hept-2-yl)ethyl(meth)acrylate,
1,1-di(tricyclo[5.2.1.0.sup.2,6]decan-8-yl)ethyl(meth)acrylate,
1,1-di(tetracyclo[6.2.1.sup.3,6.0.sup.2,7]dodecan-4-yl)ethyl(meth)acrylat-
e, 1,1-di(adamantan-1-yl)ethyl(meth)acrylate, a
1-methyl-1-cyclopentyl(meth)acrylate,
1-ethyl-1-cyclopentyl(meth)acrylate,
1-methyl-1-cyclohexyl(meth)acrylate, and
1-ethyl-1-cyclohexyl(meth)acrylate can be given. In the present
invention, (meth)acrylate refers to both acrylate and
methacrylate.
[0082] Of these monomers, 2-methyladamantyl-2-yl(meth)acrylate,
2-ethyladamantyl-2-yl(meth)acrylate,
2-methylbicyclo[2.2.1]hept-2-yl(meth)acrylate,
2-ethylbicyclo[2.2.1]hept-2-yl(meth)acrylate,
1-(bicyclo[2.2.1]hept-2-yl)-1-methylethyl (meth)acrylate,
1-(adamantan-1-yl)-1-methylethyl(meth)acrylate,
1-methyl-1-cyclopentyl(meth)acrylate,
1-ethyl-1-cyclopentyl(meth)acrylate,
1-methyl-1-cyclohexyl(meth)acrylate,
1-ethyl-1-cyclohexyl(meth)acrylate and the like are particularly
preferable.
[0083] The resin (B) may contain only one type of repeating unit
(3) or two or more types of repeating units (3).
[0084] In the formulas (4-1) to (4-6), R.sup.8 represents a
hydrogen atom or a substituted or unsubstituted alkyl group having
1 to 4 carbon atoms, R.sup.9 represents a hydrogen atom or a
methoxy group, A represents a single bond or a methylene group, B
represents an oxygen atom or a methylene group, p is an integer of
1 to 3, and m is 0 or 1.
[0085] As examples of the substituted or unsubstituted alkyl group
having 1 to 4 carbon atoms represented by R.sup.8 in the formula
(4-1), a methyl group, an ethyl group, an n-propyl group, an
i-propyl group, an n-butyl group, a 2-methylpropyl group, a
1-methylpropyl group, a t-butyl group, and the like can be
given.
[0086] As examples of the monomer providing the repeating units
(4-1) to (4-6),
5-oxo-4-oxa-tricyclo[4.2.1.0.sup.3,7]non-2-yl(meth)acrylate,
9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0.sup.3,7]non-2-yl(meth)acry-
late, 5-oxo-4-oxa-tricyclo[5.2.1.0.sup.3,8]dec-2-yl(meth)acrylate,
(10-methoxycarbonyl-5-oxo-4-oxa-tricyclo[5.2.1.0.sup.3,8]non-2-yl(meth)ac-
rylate, 6-oxo-7-oxa-bicyclo[3.2.1]oct-2-yl(meth)acrylate,
4-methoxycarbonyl-6-oxo-7-oxa-bicyclo[3.2.1]oct-2-yl(meth)acrylate,
7-oxo-8-oxa-bicyclo[3.3.1]oct-2-yl(meth)acrylate,
4-methoxycarbonyl-7-oxo-8-oxa-bicyclo[3.3.1]oct-2-yl(meth)acrylate,
2-oxotetrahydropyran-4-yl(meth)acrylate,
4-methyl-2-oxotetrahydropyran-4-yl (meth)acrylate,
4-ethyl-2-oxotetrahydropyran-4-yl(meth)acrylate,
4-propyl-2-oxotetrahydropyran-4-yl(meth)acrylate,
5-oxo-tetrahydrofuran-3-yl (meth)acrylate,
2,2-dimethyl-5-oxotetrahydrofuran-3-yl(meth)acrylate,
4,4-dimethyl-5-oxotetrahydrofuran-3-yl(meth)acrylate,
2-oxotetrahydrofuran-3-yl (meth)acrylate,
4,4-dimethyl-2-oxotetrahydrofuran-3-yl(meth)acrylate,
5,5-dimethyl-2-oxotetrahydrofuran-3-yl(meth)acrylate,
2-oxotetrahydrofuran-3-yl (meth)acrylate,
5-oxotetrahydrofuran-2-ylmethyl(meth)acrylate,
3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl(meth)acrylate, methyl
4,4-dimethyl-5-oxotetrahydrofuran-2-ylmethyl(meth)acrylate, and the
like can be given.
[0087] The resin (B) may contain only one type of repeating unit or
two or more types of the repeating units (4-1) to (4-6).
[0088] The resin (B) of the present invention may comprise one or
more repeating units other than the repeating unit (3) or the
repeating units (4-1) to (4-6) (hereinafter referred to as "other
repeating units").
[0089] As examples of the other repeating units, a repeating unit
of the following formula (5) (hereinafter called "repeating unit
(5)"), a repeating unit of the following formula (6) (hereinafter
called "repeating unit (6)"), and a repeating unit of the following
formula (7) (hereinafter called "repeating unit (7)") can be
given.
##STR00015##
wherein R.sup.14 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group and W represents an alicyclic hydrocarbon
group having 7 to 20 carbon atoms which may be substituted or
unsubstituted with an alkyl group having 1 to 4 carbon-atoms, a
hydroxyl group, a cyano group, or a hydroxy alkyl group having 1 to
10 carbon atoms.
[0090] As examples of the substituted or unsubstituted
polyalicyclic hydrocarbon group having 7 to 20 carbon atoms
represented by W of the repeating unit (5), hydrocarbon groups
originating from cycloalkanes such as bicyclo[2.2.1]heptane (5a),
bicyclo[2.2.2]octane (5b), tricyclo[5.2.1.0.sup.2,6]decane (5c),
tetracyclo[6.2.1.1.sup.3,6.0.sup.2,7]dodecane (5d), and
tricyclo[3.3.1.1.sup.3,7]decane (5e) which are shown by the
following formulas can be given.
##STR00016##
[0091] When the hydrocarbon group originating from the cycloalkanes
has a substituent, cyclic, branched, or liner alkyl groups having 1
to 4 carbon atoms such as a methyl group, an ethyl group, an
n-propyl group, an i-propyl group, an n-butyl group, a
2-methylpropyl group, a 1-methylpropyl group, and a t-butyl group
can be given as examples of the substituents. They are not limited
to the compounds substituted with the above alkyl groups and may
include compounds substituted with a hydroxyl group, a cyano group,
a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group,
or oxygen.
[0092] As examples of the monomer providing the repeating unit (5),
bicyclo[2.2.1]heptyl(meth)acrylate, cyclohexyl(meth)acrylate,
bicyclo[4.4.0]decanyl (meth)acrylate,
bicyclo[2.2.2]octyl(meth)acrylate, tricyclo[5.2.1.0.sup.2,6]decanyl
(meth)acrylate,
tetracyclo[6.2.1.1.sup.3,6.0.sup.2,7]dodecanyl(meth)acrylate, and
tricyclo[3.3.1.1.sup.3,7]decanyl(meth)acrylate can be given.
[0093] The resin (B) may contain only one type of repeating unit
(5) or two or more types of repeating unit (5).
##STR00017##
wherein R.sup.15 represents a hydrogen atom or a methyl group, Z
represents a single bond or a divalent organic group having 1 to 3
carbon atoms, Y individually represents a single bond or a divalent
organic group having 1 to 3 carbon atoms, R.sup.16 individually
represents a hydrogen atom, a hydroxyl group, a cyano group, or a
COOR.sup.17 group, (wherein R.sup.17 represents a hydrogen atom, a
linear or branched alkyl group having 1 to 4 carbon atoms, or an
alicyclic alkyl group having 3 to 20 carbon atoms), at least one of
the three R.sup.16s is not a hydrogen atom and when Z is a single
bond, at least one of the three Ys is a divalent organic group
having 1 to 3 carbon atoms.
[0094] As examples of the divalent organic group having 1 to 3
carbon atoms represented by Z and Y in the repeating unit (6), a
methylene group, an ethylene group, and a propylene group can be
given.
[0095] Examples of the linear or branched alkyl group having 1 to 4
carbon atoms represented by R.sup.17 in the group COOR.sup.17
include a methyl group, an ethyl group, an n-propyl group, an
i-propyl group, an n-butyl group, a 2-methylpropyl group, a
1-methylpropyl group, and a t-butyl group.
[0096] As examples of the alicyclic alkyl group having 3 to 20
carbon atoms represented by R.sup.17, cycloalkyl groups shown by
the formula --C.sub.tH.sub.2t-1 (wherein t is an integer of 3 to
20), polyalicyclic groups, and the like can be given. Examples of
the cycloalkyl group include a cyclopropyl group, cyclobutyl group,
cyclopentyl group, cyclohexyl group, a cycloheptyl group, and a
cyclooctyl group. In addition, as examples of the polyalicyclic
group, a bicyclo[2.2.1]heptyl group, a
tricyclo[5.2.1.0.sup.2,6]decyl group, a
tetracyclo[6.2.1.1.sup.3,6.0.sup.2,7]dodecanyl group, and adamantyl
group can be given. The cycloalkyl group or the polycyclic
alicyclic alkyl group may be substituted with one or more linear,
branched, or cyclic alkyl group. These substituents may be two or
more different groups.
[0097] As examples of the monomer providing with the repeating unit
(6), 3-hydroxyadamantan-1-ylmethyl(meth)acrylate,
3,5-dihydroxyadamantan-1-ylmethyl (meth)acrylate,
3-hydroxy-5-methyladamantan-1-yl(meth)acrylate,
3,5-dihydroxy-7-methyladamantan-1-yl(meth)acrylate,
3-hydroxy-5,7-dimethyladamantan-1-yl(meth)acrylate, and
3-hydroxy-5,7-dimethyladamantan-1-ylmethyl(meth)acrylate can be
given.
[0098] The resin (B) may contain only one type of repeating unit
(6) or two or more types of repeating units (6).
##STR00018##
wherein R.sup.18 represents a hydrogen atom, an alkyl group having
1 to 4 carbon atoms, a trifluoromethyl group, or a hydroxymethyl
group, and R.sup.19 represents a divalent organic group.
[0099] As examples of the alkyl group having 1 to 4 carbon atoms
represented by R.sup.18 in the repeating unit (7), a methyl group,
an ethyl group, an n-propyl an group, i-propyl group, an n-butyl
group, a 2-methylpropyl group, a 1-methylpropyl group, and a
t-butyl group can be given.
[0100] The divalent organic group represented by R.sup.19 in the
repeating unit (7) is preferably a divalent hydrocarbon group.
Among the divalent hydrocarbon groups, a chain or cyclic
hydrocarbon group is preferable. Such a group may also be an
alkylene glycol group, an alkylene ester group, or the like.
[0101] Specific examples include saturated linear hydrocarbon
groups such as a methylene group, an ethylene group, a propylene
group (e.g., 1,3-propylene group, 1,2-propylene group), a
tetramethylene group, a pentamethylene group, a hexamethylene
group, a heptamethylene group, an octamethylene group, a
nonamethylene group, a decamethylene group, an undecamethylene
group, a dodecamethylene group, a tridecamethylene group, a
tetradecamethylene group, a pentadecamethylene group, a
hexadecamethylene group, a heptadecamethylene group, an
octadecamethylene group, a nonadecamethylene group, an icosylene
group, a 1-methyl-1,3-propylene group, a 2-methyl-1,3-propylene
group, a 2-methyl-1,2-propylene group, a 1-methyl-1,4-butylene
group, a 2-methyl-1,4-butylene group, a methylidene group, an
ethylidene group, a propylidene group, and a 2-propylidene
group;
monocycle hydrocarbon ring groups, for example, cycloalkylene
groups having 3 to 10 carbon atoms, such as cyclobutylene groups
(e.g., 1,3-cyclobutylene group), cyclopentylene groups (e.g.,
1,3-cyclopentylene group), cyclohexylene groups (e.g.,
1,4-cyclohexylene group), and cycloctylene groups (e.g.,
1,5-cycloctylene group); bridged cyclic hydrocarbon ring groups
having 4 to 30 carbon atoms in 2 to 4 rings, for example,
norbornylene groups (e.g., 1,4-norbornylene group, 2,5-norbornylene
group) and admantylene groups (e.g., 1,5-admantylene group and
2,6-admantylene group); and the like. Among the above groups, a
hydrocarbon group having a 2,5-norbornylene group, a 1,2-ethylene
group, and a propylene group is preferable as R.sup.19.
[0102] When as R.sup.19 includes a divalent alicyclic hydrocarbon
group, it is preferable to insert an alkylene group having 1 to 4
carbon atoms as a spacer between the bistrifluoromethyl
hydroxylmethyl group [--C(CF.sub.3).sub.2OH] and the divalent
alicyclic hydrocarbon group.
[0103] As preferable examples of the monomer providing the
repeating unit (7), [0104]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl)(meth)acrylate,
[0105]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl)(meth)acrylat-
e, [0106]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl)(meth)acry-
late, [0107]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl)(meth)acrylate,
[0108]
2-{[5-(1',1',1'-trifluoro-2'-trifluoromethyl-2'-hydroxy)propyl]bic-
yclo[2.2.1]heptyl}(meth)acrylate, [0109]
3-{[8-(1',1',1'-trifluoro-2'-trifluoromethyl-2'-hydroxy)propyl]tetracyclo-
[6.2.1.1.sup.3,6.0.sup.2,7]dodecyl}(meth)acrylate, and the like can
be given.
[0110] The resin (B) may contain only one type of repeating unit
(7) or two or more types of repeating units (7).
[0111] Examples of the repeating units other than the repeating
units (5) to (7) (hereinafter referred to from time to time as
"repeating unit (15)") include units obtainable by cleavage of a
polymerizable unsaturated bond of a polyfunctional monomer such as
(meth)acrylates having a bridged hydrocarbon skeleton such as
dicyclopentenyl (meth)acrylate and adamantylmethyl(meth)acrylate;
carboxyl group-containing esters having a bridged hydrocarbon
skeleton of unsaturated carboxylic acid such as
carboxynorbornyl(meth)acrylate,
carboxytricyclodecanyl(meth)acrylate, and
carboxytetracycloundecanyl(meth)acrylate;
(meth)acrylates having no bridged hydrocarbon skeleton such as
methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate,
n-butyl(meth)acrylate, 2-methylpropyl (meth)acrylate,
1-methylpropyl(meth)acrylate, t-butyl(meth)acrylate, 2-hydroxyethyl
(meth)acrylate, 2-hydroxypropyl(meth)acrylate,
3-hydroxypropyl(meth)acrylate, cyclopropyl(meth)acrylate,
cyclopentyl(meth)acrylate, cyclohexyl(meth)acrylate,
4-methoxycyclohexyl(meth)acrylate,
2-cyclopentyloxycarbonylethyl(meth)acrylate,
2-cyclohexyloxycarbonylethyl(meth)acrylate, and 2-(4-methoxy
cyclohexyl)oxycarbonylethyl(meth)acrylate;
.alpha.-hydroxymethylacrylates such as methyl .alpha.-hydroxymethyl
acrylate, ethyl .alpha.-hydroxymethyl acrylate, n-propyl
.alpha.-hydroxymethyl acrylate, and n-butyl-.alpha.-hydroxymethyl
acrylate; unsaturated nitryl compounds such as (meta)acrylonitrile,
.alpha.-chloroacrylonitrile, crotonitrile, maleinitrile,
fumamitrile, mesaconitrile, citraconitrile, and itaconitrile;
unsaturated amide compounds such as (meth)acrylamide,
N,N-dimethyl(meth)acrylamide, crotonamide, maleinamide, fumaramide,
mesaconamide, citraconamide, and itaconamide; other
nitrogen-containing vinyl compounds such as
N-(meth)acryloylmorpholine, N-vinyl-.epsilon.-caprolactam,
N-vinylpyrrolidone, vinylpyridine, and vinylimidazole; unsaturated
carboxylic acid (anhydride) such as (meth)acrylic acid, crotonic
acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid,
itaconic anhydride, citraconic acid, citraconic anhydride, and
mesaconic acid; carboxyl group-containing esters having no bridged
hydrocarbon skeleton of unsaturated carboxylic acid such as
2-carboxyethyl(meth)acrylate, 2-carboxypropyl(meth)acrylate,
3-carboxypropyl(meth)acrylate, 4-carboxybutyl (meth)acrylate, and
4-carboxycyclohexyl(meth)acrylate; polyfunctional monomers having a
bridged hydrocarbon skeleton such as 1,2-adamantanediol
di(meth)acrylate, 1,3-adamantanediol di(meth)acrylate,
1,4-adamantanediol di(meth)acrylate, and tricyclodecanyldimethylol
di(meth)acrylate; and polyfunctional monomers having no bridged
hydrocarbon skeleton such as methylene glycol di(meth)acrylate,
ethylene glycol di(meth)acrylate, propylene glycol
di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,
2,5-dimethyl-2,5-hexanediol di(meth)acrylate, 1,8-octanediol
di(meth)acrylate, 1,9-nonanediol di(meth)acrylate,
1,4-bis(2-hydroxypropyl)benzene di(meth)acrylate, and
1,3-bis(2-hydroxypropyl)benzene di(meth)acrylate.
[0112] Of these repeating units (15), the units obtained by
cleavage of a polymerizable unsaturated bond of (meth)acrylates
having a bridged hydrocarbon skeleton and the like are
preferable.
[0113] It is preferable that the resin (B) of the present invention
contain at least one other repeating unit selected from these other
repeating units.
<Resin (B2) Containing Crosslinking Group and Acid-Unstable
Group>
[0114] The polymer (B2) having a crosslinking group and an
acid-unstable group (hereinafter referred as "polymer (B2)") has
either or both of the following crosslinking groups bonded to the
polymer (B1) mentioned above.
##STR00019##
wherein R.sup.10 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, D represents a methylene group, an ethylene
group, or a propylene group; and R.sup.11 is a group shown by the
following formula (5-1-A) or the following formula (5-1-B).
##STR00020##
[0115] In the formula (5-2), R.sup.10 represents a hydrogen atom, a
methyl group, or a trifluoromethyl group, R.sup.12 represents a
methylene group or an alkylene group having 2 to 6 carbon atoms,
R.sup.13 represents a hydrogen atom, a methyl group, or an ethyl
group, and n is 0 or 1.
[0116] The content of the repeating unit (3) in the polymer (B1) or
polymer (B2) of the first resist layer forming resin composition of
the present invention is preferably 10 to 90 mol %, and more
preferably 10 to 80 mol %, and still more preferably 20 to 70 mol %
for 100 mol % of all the repeating units contained in the polymer
(B1). If the content of the repeating unit (3) is less than 10 mol
%, resolution as a resist film may decrease. If more than 90 mol %,
the developability of the resist film may decrease.
[0117] The content of the repeating units (4-1) to (4-6) is
preferably 5 to 70 mol %, more preferably 5 to 65 mol %, and still
more preferably 10 to 60 mol % for 100 mol % of all the repeating
units contained in the polymer (B1) or the polymer (B2). If the
content of the repeating unit (4) is less than 5 mol %,
developability and process margin as a resist may decrease.
[0118] The content of the repeating unit (5) is preferably 30 mol %
or less, and more preferably 25 mol % or less for 100 mol % of all
repeating units contained in the polymer (B1) or polymer (B2). If
the content of the repeating unit (5) is more than 30 mol %, the
resist film produced tends to swell in an alkali developer and
solubility in an alkali developer may decrease.
[0119] The content of the repeating unit (6) is preferably 30 mol %
or less, and more preferably 25 mol % or less for 100 mol % of all
repeating units contained in the polymer (B1) or polymer (B2). If
the content of the repeating unit (6) is more than 30 mol %, the
resist film produced tends to swell in an alkali developer and
solubility in an alkali developer may decrease.
[0120] The content of the repeating unit (7) is preferably 30 mol %
or less, and more preferably 25 mol % or less for 100 mol % of all
repeating units contained in the polymer (B1) or polymer (B2). If
the content of the repeating unit (7) is more than 30 mol %, a top
loss of the resist pattern may be produced, giving rise to the
possibility of impairing the pattern profile.
[0121] The first resist layer forming resin composition may contain
only one type of the polymer (B1) or the polymer (B2) or may
contain two or more of types of the polymer (B1) and the polymer
(B2).
[0122] The resin (B1) or the resin (B2) in the present invention
may be prepared by polymerizing the polymerizable unsaturated
monomers for constituting the above described each repeating unit
in an appropriate solvent in the presence of a chain transfer
agent, as required, using a radical polymerization initiator such
as a hydroperoxides, dialkyl peroxides, diacyl peroxides, or azo
compounds.
[0123] As examples of the solvent used for polymerization, alkanes
such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and
n-decane; cycloalkanes such as cyclohexane, cycloheptane,
cyclooctane, decalin, and norbornane; aromatic hydrocarbons such as
benzene, toluene, xylene, ethylbenzene, and cumene; halogenated
hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes,
hexamethylene dibromide, and chlorobenzene; saturated carboxylic
acid esters such as ethyl acetate, n-butyl acetate, i-butyl
acetate, and methyl propionate; ketones such as acetone,
2-butanone, 4-methyl-2-pentanone, and 2-heptanone; and ethers such
as tetrahydrofuran, dimethoxyethanes, and diethoxyethanes can be
given. These solvents may be used either individually or in
combination of two more more.
[0124] The polymerization temperature is usually 40 to 150.degree.
C., and preferably 50 to 120.degree. C. The reaction time is
usually 1 to 48 hours, and preferably 1 to 24 hours.
[0125] Although not particularly limited, the polystyrene-reduced
weight average molecular weight (hereinafter referred to from time
to time as "Mw") of the polymer (B1) or the polymer (B2) determined
by gel permeation chromatography (GPC) is preferably 1000 to
100,000, more preferably 1000 to 30,000, and still more preferably
1000 to 20,000. If the Mw of the polymer (B1) or the polymer (B2)
is less than 1000, the heat resistance of the resist film may
decrease. If the Mw of the resin is more than 100,000, the
developability of the resist film may decrease.
[0126] The ratio of the Mw to the polystyrene-reduced number
average molecular weight (hereinafter referred to as "Mn")
determined by gel permeation chromatography (GPC) (Mw/Mn) of the
polymer (B1) or the polymer (B2) is usually 1 to 5, and preferably
1 to 3.
[0127] The polymer (B1) or the polymer (B2) may contain low
molecular weight components originating from the monomers used when
preparing the resin. The amount of the low molecular weight
components in the polymer (B1) or the polymer (B2) is preferably
not more than 0.1 mass %, more preferably not more than 0.07 mass
%, and still more preferably not more than 0.05 mass % for 100 mass
% (reduced to solid components) of the polymer (B1) or the polymer
(B2). When this content is not more than 0.1 mass %, the amount of
elusion in the liquid for liquid immersion lithography such as
water with which the resist film comes in contact during exposure
can be reduced. In addition, it is possible to prevent generation
of extraneous substances in the resist during storage,
inhibit-uneven resist application, and sufficiently suppress
production of defects during resist pattern formation.
[0128] The low molecular weight components may be components having
an Mw of 500 or less such as monomers, dimers, trimers, and
oligomers. The low molecular weight components (components having
an Mw of 500 or less) may be removed by purification using a
chemical purification process such as washing with water or
liquid-liquid extraction or a combination of the chemical
purification process and a physical purification process such as
ultrafiltration or centrifugation, for example. The content of the
low molecular weight components may be determined by high
performance liquid chromatography (HPLC).
[0129] It is preferable that the polymer (B1) or the polymer (B2)
contain only a small amount of impurities such as halogens and
metals. The sensitivity, resolution, process stability, pattern
shape, and the like of the formed resist film can be improved by
reducing such impurities.
[0130] The polymer (B1) or the polymer (B2) can be purified using,
for example, a chemical purification method such as washing with
water or liquid-liquid extraction or a combination of the chemical
purification method and a physical purification method such as
ultrafiltration or centrifugation.
<Radiation-Sensitive Acid Generator (C)>
[0131] The radiation-sensitive acid generator (hereinafter referred
to from time to time as "acid generator") generates an acid by
being exposed to radiation and causes an acid-dissociable group,
specifically, the acid-dissociable group possessed by the repeating
unit (3) in the polymer component, to dissociate (disconnect a
blocking group) by the action of the acid generated upon exposure.
As a result, an exposed part of the resist film becomes readily
soluble in an alkaline developer, thereby forming a
positive-working resist pattern.
[0132] As such an acid generator, a compound shown by the following
formula (8) (hereinafter referred to as an "acid generator 1") is
preferable.
##STR00021##
wherein R.sup.20 represents a hydrogen atom, a fluorine atom, a
hydroxyl group, a linear or branched alkyl group having 1 to 10
carbon atoms, a linear or branched alkoxyl group having 1 to 10
carbon atoms, or a linear or branched alkoxycarbonyl group having 2
to 11 carbon atoms, R.sup.21 represents a linear or branched alkyl
group having 1 to 10 carbon atoms, a linear or branched alkoxyl
group having 1 to 10 carbon atoms, or a linear, branched, or cyclic
alkanesulfonyl group having 1 to 10 carbon atoms, R.sup.22
individually represents a linear or branched alkyl group having 1
to 10 carbon atoms, a substituted or unsubstituted phenyl group, or
a substituted or unsubstituted naphthyl group, or two R.sup.22
groups bond to form a substituted or unsubstituted divalent group
having 2 to 10 carbon atoms, k is an integer of 0 to 2, X''
represents an anion represented by the formula
R.sup.23C.sub.qF.sub.2qSO.sub.3.sup.- or R.sup.23SO.sub.3.sup.-
(wherein R.sup.23 represents a fluorine atom or a substituted or
unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and q
is an integer of 1 to 10), or an anion represented by the following
formula (9-1) or (9-2), and r is an integer of 1 to 10;
##STR00022##
wherein R.sup.24 individually represents a linear or branched alkyl
group having a fluorine atom and 1 to 10 carbon atoms, or two
R.sup.24 groups in combination represent a divalent organic group
having a fluorine atom and 2 to 10 carbon atoms, wherein the
divalent organic group may have a substituent.
[0133] In the formula (8), as examples of the linear or the
branched alkyl group having 1 to 10 carbon atoms for R.sup.20,
R.sup.21, and R.sup.22, a methyl group, an ethyl group, an n-propyl
group, an i-propyl group, an n-butyl group, a 2-methylpropyl group,
a 1-methylpropyl group, a t-butyl group, an n-pentyl group, a
neopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl
group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group,
and the like can be given. Of these alkyl groups, a methyl group,
an ethyl group, an n-butyl group, a t-butyl group, and the like are
preferable.
[0134] Examples of the linear or branched alkoxyl group having 1 to
10 carbon atoms represented by R.sup.20 and R.sup.21 include a
methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy
group, an n-butoxy group, a 2-methylpropoxy group, a
1-methylpropoxy group, a t-butoxy group, an n-pentyloxy group, a
neopentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an
n-octyloxy group, a 2-ethylhexyloxy group, an n-nonyloxy group, and
an n-decyloxy group. Of these alkoxyl group, a methoxy group, an
ethoxy group, an n-propoxy group, and a t-butoxy group are
preferable.
[0135] Examples of the linear or branched alkoxycarbonyl group
having 2 to 11 carbon atoms represented by R.sup.20 include a
methoxycarbonyl group, an ethoxycarbonyl group, an
n-propoxycarbonyl group, an i-propoxycarbonyl group, an
n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, an
1-methylpropoxycarbonyl group, a t-butoxycarbonyl group, an
n-pentyloxycarbonyl group, a neopentyloxycarbonyl group, an
n-hexyloxycarbonyl group, an n-heptyloxycarbonyl group, an
n-octyloxycarbonyl group, a 2-ethylhexyloxycarbonyl group, an
n-nonyloxycarbonyl group, and an n-decyloxycarbonyl group. Of these
alkoxycarbonyl groups, a methoxycarbonyl group, an ethoxycarbonyl
group, an n-butoxycarbonyl group, and the like are preferable.
[0136] As examples of the linear, branched, or cyclic
alkanesulfonyl group having 1 to 10 carbon atoms represented by
R.sup.21, a methanesulfonyl group, an ethanesulfonyl group, an
n-propanesulfonyl group, an n-buthanesulfonyl group, a
tert-butanesulfonyl group, an n-pentanesulfonyl group, a
neopentanesulfonyl group, an n-hexanesulfonyl group, an
n-heptanesulfonyl group, an n-octanesulfonyl group, a
2-ethylhexanesulfonyl group, an n-nonanesulfonyl group, an
n-decanesulfonyl group, a cyclopentanesulfonyl group, and a
cyclohexanesulfonyl group can be given. Of these alkanesulfonyl
groups, a methanesulfonyl group, an ethanesulfonyl group, an
n-propanesulfonyl group, an n-butanesulfonyl group, a
cyclopentansulfonyl group, and a cyclohexanesulfonyl group are
preferable.
[0137] r is preferably 0 to 2.
[0138] Examples of the substituted or unsubstituted phenyl group
represented by R.sup.22 in the formula (8) include a phenyl group,
phenyl groups substituted with a linear, branched, or cyclic alkyl
group having 1 to 10 carbon atoms such as an o-tolyl group, an
m-tolyl group, a p-tolyl group, a 2,3-dimethylphenyl group, a
2,4-dimethylphenyl group, a 2,5-dimethylphenyl group, a
2,6-dimethylphenyl group, a 3,4-dimethylphenyl group, a
3,5-dimethylphenyl group, a 2,4,6-trimethylphenyl group, a
4-ethylphenyl group, a 4-t-butylphenyl group, 4-cyclohexylphenyl
group, and a 4-fluorophenyl group; and groups obtained by
substituting the phenyl groups or alkyl-substituted phenyl groups
with one or more groups such as a hydroxyl group, a carboxyl group,
a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl
group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group.
[0139] Examples of the alkoxyl group as the substituent for the
phenyl group and alkyl-substituted phenyl group include linear,
branched, or cyclic alkoxyl groups having 1 to 20 carbon atoms such
as a methoxy group, an ethoxy group, an n-propoxy group, an
i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, a
1-methylpropoxy group, a t-butoxy group, a cyclopentyloxy group,
and a cyclohexyloxy group.
[0140] Examples of the alkoxyalkyl group include linear, branched,
or cyclic alkoxyalkyl groups having 2 to 21 carbon atoms such as a
methoxymethyl group, an ethoxymethyl group, a 1-methoxyethyl group,
a 2-methoxyethyl group, a 1-ethoxyethyl group, and a 2-ethoxyethyl
group.
[0141] Examples of the alkoxycarbonyl group include linear,
branched, or cyclic alkoxycarbonyl groups having 2 to 21 carbon
atoms such as a methoxycarbonyl group, an ethoxycarbonyl group, an
n-propoxycarbonyl group, an i-propoxycarbonyl group, an
n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, a
1-methylpropoxycarbonyl group, a t-butoxycarbonyl group, a
cyclopentyloxycarbonyl group, and a cyclohexyloxycarbonyl
group.
[0142] Examples of the alkoxycarbonyloxy group include linear,
branched, or cyclic alkoxycarbonyloxy groups having 2 to 21 carbon
atoms such as a methoxycarbonyloxy group, an ethoxycarbonyloxy
group, an n-propoxycarbonyloxy group, an i-propoxycarbonyloxy
group, an n-butoxycarbonyloxy group, a t-butoxycarbonyloxy group, a
cyclopentyloxycarbonyl group, and a cyclohexyloxycarbonyl
group.
[0143] Preferable phenyl groups which may have a substituent
represented by R.sup.22 in the formula (8) are a phenyl group, a
4-cyclohexylphenyl group, a 4-t-butylphenyl group, a
4-methoxyphenyl group, a 4-t-butoxyphenyl group, and the like.
[0144] Examples of the substituted or unsubstituted naphthyl group
for R.sup.22 include naphthyl groups such as a 1-naphthyl group, a
2-methyl-1-naphthyl group, a 3-methyl-1-naphthyl group, a
4-methyl-1-naphthyl group, a 5-methyl-1-naphthyl group, a
6-methyl-1-naphthyl group, a 7-methyl-1-naphthyl group, an
8-methyl-1-naphthyl group, a 2,3-dimethyl-1-naphthyl group, a
2,4-dimethyl-1-naphthyl group, a 2,5-dimethyl-1-naphthyl group, a
2,6-dimethyl-1-naphthyl group, a 2,7-dimethyl-1-naphthyl group, a
2,8-dimethyl-1-naphthyl group, a 3,4-dimethyl-1-naphthyl group, a
3,5-dimethyl-1-naphthyl group, a 3,6-dimethyl-1-naphthyl group, a
3,7-dimethyl-1-naphthyl group, a 3,8-dimethyl-1-naphthyl group, a
4,5-dimethyl-1-naphthyl group, a 5,8-dimethyl-1-naphthyl group, a
4-ethyl-1-naphthyl group, a 2-naphthyl group, a 1-methyl-2-naphthyl
group, a 3-methyl-2-naphthyl group, and a 4-methyl-2-naphthyl group
or naphtyl groups substituted with a linear, branched, or cyclic
alkyl group having 1 to 10 carbon atoms such as a naphthyl group;
and groups obtained by further substituting the naphthyl group or
alkyl-substituted naphthyl group with at least one and at least one
kind of group such as a hydroxyl group, a carboxyl group, a cyano
group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an
alkoxycarbonyl group, or an alkoxycarbonyloxy group.
[0145] As examples of the alkoxyl group, an alkoxyalkyl group, an
alkoxycarbonyl group, and an alkoxycarbonyloxy group which are the
substituents, the groups illustrated for the phenyl group and
alkyl-substituted phenyl groups can be given.
[0146] As the naphtyl group which may have a substituent
represented by R.sup.22 in the formula (8), a 1-naphthyl group, a
1-(4-methoxynaphthyl) group, a 1-(4-ethoxynaphthyl) group, a
1-(4-n-propoxynaphtyp group, a 1-(4-n-butoxynaphthyl) group, a
2-(7-methoxynaphtyl) group, a 2-(7-ethoxynaphtyl) group, a
2-(7-n-propoxynaphtyl) group, a 2-(7-n-butoxynaphtyl) group, and
the like are preferable.
[0147] As an example of the divalent group having 2 to 10 carbon
atoms formed by two R.sup.22 groups, a group forming a 5 or 6
member ring together with the sulfur atom in the formula (8),
particularly preferably a 5 member ring (i.e. tetrahydrothiophene
ring) is preferable.
[0148] As examples of the substituent for the above divalent
groups, the groups previously mentioned for the phenyl group and
alkyl-substituted phenyl groups, such as a hydroxyl group, a
carboxyl group, a cyano group, a nitro group, an alkoxyl group, an
alkoxyalkyl group, an alkoxycarbonyl group, and an
alkoxycarbonyloxy group can be given.
[0149] As the group R.sup.22 in the formula (8), a methyl group, an
ethyl group, a phenyl group, a 4-methoxyphenyl group, a 1-naphthyl
group, and a divalent group having a tetrahydrothiophene cyclic
structure formed by two R.sup.22 groups together with the sulfur
atom, and the like are preferable.
[0150] X.sup.- in the formula (8) is an anion shown by
R.sup.23C.sub.qF.sub.2qSO.sub.3.sup.-, R.sup.23SO.sub.3.sup.-, or
the above formulas (9-1) or (9-2). When X.sup.- is
R.sup.23C.sub.qF.sub.2qSO.sub.3.sup.-, the --C.sub.qF.sub.2q--
group is a linear or branched perfluoroalkylene group having carbon
atoms of the number q. q is preferably 1, 2, 4, or 8.
[0151] As a hydrocarbon group having 1 to 12 carbon atoms which may
have a substituent represented by R.sup.23, an alkyl group, a
cycloalkyl group, and a bridge alicyclic hydrocarbon group having 1
to 12 carbon atoms are preferable.
[0152] As specific examples, a methyl group, an ethyl group, an
n-propyl group, an i-propyl group, an n-butyl group, a
2-methylpropyl group, a 1-methylpropyl group, a t-butyl group, an
n-pentyl group, a neopentyl group, an n-hexyl group, a cyclohexyl
group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group,
an n-nonyl group, an n-decyl group, a norbornyl group, a
norbornylmethyl group, a hydroxynorbornyl group, and an adamantyl
group can be given.
[0153] When X.sup.- is an anion shown by the formula (9-1) or
(9-2), R.sup.24 individually may represent a linear or branched
alkyl group having a fluorine atom and 1 to 10 carbon atoms, or two
R.sup.24 groups in combination may represent a divalent organic
group having a fluorine atom and 2 to 10 carbon atoms, wherein the
divalent organic group may have a substituent.
[0154] A trifluoromethyl group, a pentafluoroethyl group, a
heptafuluoropropyl group, a nonafluorobutyl group, a
dodecafluoropentyl group, a perfluorooctyl group, and the like can
be given as examples of R.sup.24 when R.sup.24 in the formula (9-1)
or (9-2) is a linear or branched alkyl group having 1 to 10 carbon
atoms.
[0155] A tetrafluoroethylene group, a hexafluoropropylene group, an
octafluorobutylene group, a decafluoropentylene group, an
undecafluorohexylene group, and the like can be given as examples
of R.sup.24 when R.sup.24 is a divalent organic group having 2 to
10 carbon atoms.
[0156] Accordingly, preferable examples of the anion r in the
formula (8) are trifluoromethanesulfonate anion,
perfluoro-nLbutanesulfonate anion, perfluoro-n-octanesulfonate
anion, 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate
anion, 2-bicyclo[2.2.1]hept-2-yl-1,1-difluoroethanesulfonate anion,
and the anions shown by the following formulas (10-1) to
(10-7).
##STR00023##
[0157] As preferable specific examples of the compound of the
formula (8), the following compounds can be given. [0158]
triphenylsulfonium trifluoromethanesulfonate, [0159]
tri-t-butylphenylsulfonium trifluoromethanesulfonate, [0160]
4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate,
[0161] 4-methanesulfonylphenyl-diphenylsulfonium
trifluoromethanesulfonate, [0162]
1-(3,5-dimethyl-4-hydroxyphenyptetrahydrothiophenium
trifluoromethanesulfonate, [0163]
1-(4-n-butoxynaphthyl)tetrahydrothiophenium
trifluoromethanesulfonate, [0164] triphenylsulfonium
perfluoro-n-butanesulfonate, [0165] tri-t-butylphenylsulfonium
perfluoro-n-butanesulfonate, [0166]
4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate,
[0167] 4-methanesulfonylphenyl-dipbenzylsulfonium
perfluoro-n-butanesulfonate, [0168]
1-(3,5-dimethyl-4-hydroxyphenyptetrahydrothiophenium
perfluoro-n-butanesulfonate, [0169]
1-(4-n-butoxynaphthyl)tetrahydrothiophenium
perfluoro-n-butanesulfonate, [0170] triphenylsulfonium
perfluoro-n-octanesulfonate, [0171] tri-t-butylphenylsulfonium
perfluoro-n-octanesulfonate, [0172]
4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octanesulfonate,
[0173] 4-methanesulfonylphenyl-diphenylsulfonium
perfluoro-n-octanesulfonate, [0174]
1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophenium
perfluoro-n-octanesulfonate, [0175]
1-(4-n-butoxynaphthyl)tetrahydrothiophenium
perfluoro-n-octanesulfonate, [0176] triphenylsulfonium
2-(bicyclo[2.2.1]hept-2'-yl)-1,1,2,2-tetrafluoroethanesulfonate,
[0177] tri-tert-butylphenylsulfonium [0178]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1,2,2-tetrafluoroethanesulfonate,
[0179] 4-cyclohexylphenyldiphenylsulfonium [0180]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1,2,2-tetrafluoroethanesulfonate,
[0181] 4-methanesulfonylphenyl-diphenylsulfonium [0182]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1,2,2-tetrafluoroethanesulfonate,
[0183] 1-(3,5-dimethyl-4-hydroxyphenyptetrahydrothiophenium [0184]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1,2,2-tetrafluoroethanesulfonate,
[0185] 1-(4-n-butoxynaphthyl)tetrahydrothiophenium [0186]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1,2,2-tetrafluoroethanesulfonate,
[0187] triphenylsulfonium
2-(bicyclo[2.2.1]hept-2'-yl)-1,1-difluoroethanesulfonate, [0188]
tri-tert-butylphenylsulfonium
2-(bicyclo[2.2.1]hept-2'-yl)-1,1-difluoroethanesulfonate, [0189]
4-cyclohexylphenyl diphenylsulfonium [0190]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1-difluoroethanesulfonate, [0191]
4-methanesulfonylphenyl-diphenylsulfonium [0192]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1-difluoroethanesulfonate, [0193]
1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophenium [0194]
2-(bicyclo[2.2.1]hept-2'-yl)-1,1-difluoroethanesulfonate, [0195]
1-(4-n-butoxynaphthyl)tetrahydrothiophenium [0196]
2-bicyclo[2.2.1]hept-2'-yl-1,1-difluoroethanesulfonate, and [0197]
compounds shown by the following formulas (C1) to (C15).
##STR00024## ##STR00025## ##STR00026## ##STR00027##
[0198] The above-described acid generator 1 may be used either
individually or in combinations of two or more.
[0199] As examples of the radiation-sensitive acid generators other
than the acid generator 1 (hereinafter referred to as "other acid
generator"), onium salts, halogen-containing compounds, diazoketone
compounds, sulfone compounds, and sulfonate compounds can be given.
Examples of the other acid generators are given below.
Onium Salt Compounds:
[0200] As examples of the onium salt compounds, an iodonium salt, a
sulfonium salt, a phosphonium salt, a diazonium salt, and a
pyridinium salt can be given.
[0201] As specific examples of the onium salt compounds,
diphenyliodonium trifluoromethanesulfonate, diphenylioodonium
nonafluoro-n-butanesulfonate, diphenyliodonium
perfluoro-n-octanesulfonate, diphenyliodonium
2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate,
bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate,
bis(4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate,
bis(4-t-butylphenyl)iodonium perfluoro-n-octanesulfonate,
bis(4-t-butylphenyl)iodonium
2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate,
cyclohexyl-2-oxocyclohexylmethylsulfonium
trifluoromethanesulfonate, dicyclohexyl-2-oxocyclohexylsulfonium
trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium
trifluoromethanesulfonate, and the like can be given.
Halogen-Containing Compounds:
[0202] As examples of the halogen-containing compound, haloalkyl
group-containing hydrocarbon compounds and haloalkyl
group-containing heterocyclic compounds can be given.
[0203] As specific examples of the halogen-containing compound,
(trichloromethyl)-s-triazine derivatives such as
phenylbis(trichloromethyl)-s-triazine,
4-methoxyphenylbis(trichloromethyl)-s-triazine,
1-naphthylbis(trichloromethyl)-s-triazine, and
1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane can be given.
Diazoketone Compound:
[0204] As examples of the diazoketone compound, 1,3-diketo-2-diazo
compounds, diazobenzoquinone compounds, and diazonaphthoquinone
compounds can be given.
[0205] As specific examples of the diazoketone compound,
1,2-naphthoquinonediazido-4-sulfonyl chloride,
1,2-naphthoquinonediazido-5-sulfonyl chloride,
1,2-naphthoquinonediazido-4-sulfonate or
1,2-naphthoquinonediazido-5-sulfonate of
2,3,4,4'-tetrahydroxybenzophenone, and
1,2-naphthoquinonediazido-4-sulfonate or
1,2-naphthoquinonediazido-5-sulfonate of
1,1,1-tris(4-hydroxyphenyl)ethane can be given.
Sulfone Compounds:
[0206] As examples of the sulfone compound, .beta.-ketosulfone,
.beta.-sulfonylsulfone, and .alpha.-diazo compounds of these
compounds can be given.
[0207] As specific examples of the sulfone compound,
4-trisphenacylsulfone, mesitylphenacylsulfone,
bis(phenylsulfonyl)methane, and the like can be given.
Sulfonic Acid Compounds:
[0208] As examples of the sulfonic acid compound, alkyl sulfonates,
alkyl sulfonylimides, haloalkyl sulfonates, aryl sulfonates, and
imino sulfonates can be given.
[0209] As specific examples of the sulfone compounds,
benzointosylate, tris(trifluoromethanesulfonate) of pyrogallol,
nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate,
trifluoromethanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide,
nonafluoro-n-butanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide,
perfluoro-n-octanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide,
2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonylbicyclo[2.2.1]-
hept-5-ene-2,3-dicarbodiimide,
N-(trifluoromethanesulfonyloxy)succinimide,
N-(nonafluoro-n-butanesulfonyloxy)succinimide,
N-(perfluoro-n-octanesulfonyloxy)succinimide,
N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy)succini-
mide, 1,8-naphthalenedicarboxylic acid imide
trifluoromethanesulfonate, 1,8-naphthalenedicarboxylic acid imide
nonafluoro-n-butanesulfonate, 1,8-naphthalenedicarboxylic acid
imide perfluoro-n-octanesulfonate, and the like can be given.
[0210] Among these other acid generators, diphenyliodonium
trifluoromethanesulfonate, diphenyliodonium
nonafluoro-n-butanesulfonate, diphenyliodonium
perfluoro-n-octanesulfonate, diphenyliodonium
2-bicyclo[2.2.1]hepta-2-yl-1,1,2,2-tetrafluoroethanesulfonate,
bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate,
bis(4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate,
bis(4-t-butylphenyl)iodonium perfluoro-n-octanesulfonate,
bis(4-t-butylphenyl)iodonium
2-bicyclo[2.2.1]hepta-2-yl-1,1,2,2-tetrafluoroethanesulfonate,
cyclohexy.2-oxocyclohexylmethylsulfonium trifluoromethanesulfonate,
dicyclohexy.2-oxocyclohexylsulfonium trifluoromethanesulfonate,
2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate,
trifluoromethanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide,
nonafluoro-n-butanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide,
perfluoro-n-octanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide,
2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonylbicyclo[2.2.1]-
hept-5-ene-2,3-dicarbodiimide,
N-(trifluoromethanesulfonyloxy)succinimide,
N-(nonafluoro-n-butanesulfonyloxy)succinimide,
N-(perfluoro-n-octanesulfonyloxy)succinimide,
N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy)succini-
mide, 1,8-naphthalenedicarboxylic acid imide
trifluoromethanesulfonate, and the like are preferable.
[0211] These other acid generators may be used either individually
or in combination of two or more.
[0212] The amount of the acid generator 1 and the other acid
generators to be used in the present invention is usually 0.1 to 20
parts by mass, and preferably 0.5 to 10 parts by mass for 100 parts
by mass of the resin (A) from the viewpoint of ensuring sensitivity
and developability as a resist. If this total amount is less than
0.1 part by mass, the sensitivity and developability as a resist
tend to be impaired. If this total amount is more than 20 parts by
mass, the transparency of the resist to radiation tends to
decrease, which makes it difficult to obtain a rectangular resist
pattern.
[0213] The proportion of the other acid generators to be added is
80 mass % or less, and preferably 60 mass % or less of the total
amount of acid generators (acid generator 1 and other acid
generators) used.
<Solvent (D)>
[0214] Examples of the "solvent (D)" contained in the first resist
layer forming resin composition include linear or branched ketones
such as 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone,
4-methyl-2-pentanone, 3-methyl-2-pentanone,
3,3-dimethyl-2-butanone, 2-heptanone, and 2-octanone; cyclic
ketones such as cyclopentanone, 3-methylcyclopentanone,
cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone,
and isophorone; propylene glycol monoalkyl ether acetates such as
propylene glycol monomethyl ether acetate, propylene glycol
monoethyl ether acetate, propylene glycol mono-n-propyl ether
acetate, propylene glycol mono-1-propyl ether acetate, propylene
glycol mono-n-butyl ether acetate, propylene glycol mono-1-butyl
ether acetate, propylene glycol mono-sec-butyl ether acetate, and
propylene glycol mono-t-butyl ether acetate; alkyl
2-hydroxypropionates such as methyl 2-hydroxypropionate, ethyl
2-hydroxypropionate, n-propyl 2-hydroxypropionate, i-propyl
2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl
2-hydroxypropionate, sec-butyl 2-hydroxypropionate, and t-butyl
2-hydroxypropionate; alkyl 3-alkoxypropionates such as methyl
3-methoxypropionate, ethyl 3-methoxypropionate, methyl
3-ethoxypropionate, and ethyl 3-ethoxypropionate;
n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl
alcohol, cyclohexanol, ethylene glycol monomethyl ether, ethylene
glycol monoethyl ether, ethylene glycol mono-n-propyl ether,
ethylene glycol mono-n-butyl ether, diethylene glycol dimethyl
ether, diethylene glycol diethyl ether, diethylene glycol
di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene
glycol monomethyl ether acetate, ethylene glycol monoethyl ether
acetate, ethylene glycol mono-n-propyl ether acetate, propylene
glycol monomethyl ether, propylene glycol monoethyl ether,
propylene glycol mono-n-propyl ether, toluene, xylene, ethyl
2-hydroxy-2-methyl propionate, ethyl ethoxyacetate, ethyl
hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl
acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl
propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate,
n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl
acetoacetate, methyl pyruvate, ethyl pyruvate, N-methyl
pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, benzyl
ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether,
diethylene glycol monoethyl ether, caproic acid, caprylic acid,
1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl
benzoate, diethyl oxalate, diethyl maleate, .gamma.-butyrolactone,
ethylene carbonate, and propylene carbonate.
[0215] Among these, linear or branched ketones, cyclic ketones,
propylene glycol monoalkyl ether acetates, alkyl
2-hydroxypropionates, alkyl 3-alkoxypropionates,
.gamma.-butyrolactone, and the like are preferable.
[0216] These solvents (D) may be used either individually or in
combinations of two or more.
[0217] The first resist layer forming resin composition of the
present invention is usually used in the form of a composition
solution prepared by dissolving the composition in the solvent (D)
so that the total solid content is usually 1 to 50 mass %, and
preferably 1 to 25 mass %, and filtering the solution using a
filter with a pore diameter of about 0.2 .mu.m, for example.
<Additives>
[0218] Various additives such as an acid diffusion controller, an
aliphatic additive, a surfactant, and a sensitizer can be
optionally added to the first resist layer forming resin
composition of the present invention.
[0219] The acid diffusion controller controls diffusion of an acid
generated from the acid generator upon exposure in the resist film
to suppress undesired chemical reactions in the unexposed area.
Addition of such an acid diffusion controller improves storage
stability of the resulting first resist layer forming resin
composition. Moreover, the addition of the acid diffusion
controller further increases resolution as a resist and suppresses
change of the resist pattern line width due to fluctuation of
post-exposure delay (PED) which is a period of time from exposure
to post-exposure heat treatment, whereby a composition with
remarkably superior process stability can be obtained.
[0220] As examples of the acid diffusion controller, tertiary amine
compounds, other amine compounds, amide group-containing compounds,
urea compounds, and other nitrogen-containing heterocyclic
compounds can be given.
[0221] As tertiary amine compounds, mono(cyclo)alkylamines such as
n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine,
n-decylamine, and cyclohexylamine; di(cyclo)alkylamines such as
di-n-butylamine, di-n-pentylamine, di-n-hexylamine,
di-n-heptylamine, di-n-octylamine, di-n-nonylamine,
di-n-decylamine, cyclohexylmethylamine, and dicyclohexylamine;
tri(cyclo)alkylamines such as triethylamine, tri-n-propylamine,
tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine,
tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine,
tri-n-decylamine, cyclohexyldimethylamine, methyldicyclohexylamine,
and tricyclohexylamine; substitute alkylamines such as
2,2',2''-nitrotriethanol; aniline, N-methylaniline,
N,N-dimethylaniline, 2-methylaniline, 3-methylaniline,
4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine,
naphthylamine, 2,4,6-tri-tert-butyl-N-methylaniline,
N-phenyldiethanolamine, 2,6-diisopropylaniline, and the like are
preferable.
[0222] Preferable examples of the above-mentioned other amine
compounds include ethylenediamine,
N,N,N',N'-tetramethylethylenediamine, tetramethylenediamine,
hexamethylenediamine, 4,4'-diaminodiphenylmethane,
4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone,
4,4'-diaminodiphenylamine, 2,2'-bis(4-aminophenyl)propane,
2-(3-aminophenyl)-2-(4-aminophenyepropane,
2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane,
2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane,
1,4-bis[1-(4-aminophenyl)-1-methylethyl]benzene,
1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene,
bis(2-dimethylaminoethyl)ether, bis(2-diethylaminoethyl)ether,
1-(2-hydroxyethyl)-2-imidazolizinone, 2-quinoxalinol,
N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and
N,N,N',N'',N''-pentamethyldiethylenetriamine.
[0223] As examples of the preferable amide group-containing
compounds, N-t-butoxycarbonyl group-containing amino compounds such
as N-t-butoxycarbonyl di-n-octylamine, N-t-butoxycarbonyl
di-n-nonylamine, N-t-butoxycarbonyl di-n-decylamine,
N-t-butoxycarbonyl dicyclohexylamine,
N-t-butoxycarbonyl-1-adamantylamine,
N-t-butoxycarbonyl-2-adamantylamine,
N-t-butoxycarbonyl-N-methyl-1-adamantylamine,
(S)-(-)-1-(t-butoxycarbonyl)-2-pyrrolidine methanol,
(R)-(+)-1-(t-butoxycarbonyl)-2-pyrrolidine methanol,
N-t-butoxycarbonyl-4-hydroxypiperidine,
N-t-butoxycarbonylpyrrolidine, N-t-butoxycarbonylpiperazine,
N-t-butoxycarbonylpiperidine,
N,N-di-t-butoxycarbonyl-1-adamantylamine,
N,N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine,
N-t-butoxycarbonyl-4,4'-diaminodiphenylmethane,
N,N'-di-t-butoxycarbonylhexamethylenediamine,
N,N,N'N'-tetra-t-butoxycarbonylhexamethylenediamine,
N,N'-di-t-butoxycarbonyl-1,7-diaminoheptane,
N,N'-di-t-butoxycarbonyl-1,8-diaminonooctane,
N,N'-di-t-butoxycarbonyl-1,9-diaminononane,
N,N'-di-t-butoxycarbonyl-1,10-diaminodecane,
N,N'-di-t-butoxycarbonyl-1,12-diaminododecane,
N,N'-di-t-butoxycarbonyl-4,4'-diaminodiphenylmethane,
N-t-butoxycarbonylbenzimidazole,
N-t-butoxycarbonyl-2-methylbenzimidazole, and
N-t-butoxycarbonyl-2-phenylbenzimidazole; formamide,
N-methylformamide, N,N-dimethylformamide, acetamide,
N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide,
pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine,
tris(2-hydroxyethyl)isocyanurate, and the like can be given.
[0224] As examples of the preferable urea compounds, urea,
methylurea, 1,1-dimethylurea, 1,3-dimethylurea,
1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tri-n-butylthiourea
can be given.
[0225] Examples of the preferable other nitrogen-containing
heterocyclic compounds include imidazoles such as imidazole,
4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole,
2-phenylbenzimidazole, 1-benzyl-2-methylimidazole, and
1-benzyl-2-methyl-1H-imidazole; pyridines such as pyridine,
2-methylpyridine, 4-methylpyridine, 2-ethylpyridine,
4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine,
2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide,
quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine, and
2,2':6',2''-terpyridine; piperazines such as piperazine and
1-(2-hydroxyethyl)piperazine; and pyrazine, pyrazole, pyridazine,
quinoxaline, purine, pyrrolidine, piperidine, piperidineethanol,
3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine,
1-(4-morpholinyl)ethanol, 4-acetylmorpholine,
3-(N-morpholino)-1,2-propanediol, 1,4-dimethylpiperazine, and
1,4-diazabicyclo[2.2.2]octane.
(Photodisintegrating BASE)
[0226] The photodisintegrating base is an onium salt compound which
generates a base exhibiting an acid diffusion controlling effect by
decomposing upon exposure to radiation. As specific examples of the
onium salt compound, the sulfonium salt compound shown by the
following formula (11) and the iodonium salt compound shown by the
following formula (12) can be given,
##STR00028##
wherein R.sup.25 to R.sup.29 individually represent a hydrogen
atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a
halogen atom and T represents OH.sup.-, RCOO.sup.-, RSO.sub.3.sup.-
(wherein R represents an alkyl group, an aryl group, or an alkaryl
group), or an anion shown by the following formula (13).
##STR00029##
[0227] As specific examples of the sulfonium salt compound and
iodonium salt compound, triphenylsulfonium hydrooxide,
triphenylsulfonium acetate, triphenylsulfonium salicylate,
diphenyl-4-hydroxyphenylsulfonium hydroxide,
diphenyl-4-hydroxyphenylsulfonium acetate,
diphenyl-4-hydroxyphenylsulfonium salicylate,
bis(4-t-butylphenyl)iodonium hydroxide,
bis(4-t-butylphenyl)iodonium acetate, bis(4-t-butylphenyl)iodonium
hydroxide, bis(4-t-butylphenyl)iodonium acetate,
bis(4-t-butylphenyl)iodonium salicylate,
4-t-butylphenyl-4-hydroxyphenyl)iodonium hydroxide,
4-t-butylphenyl-4-hydroxyphenyliodonium acetate,
4-t-butylphenyl-4-hydroxyphenyliodonium salicylate,
bis(4-t-butylphenyl)iodonium 10-camphorsulfonate, diphenyliodonium
10-camphorsulfonate, triphenylsulfonium 10-camphorsulfonate, and
4-t-butoxyphenyl diphenylsulfonium 10-camphorsulfonate can be
given.
[0228] These acid diffusion controllers may be used either
individually or in combinations of two or more.
[0229] The amount of acid diffusion controller to be added is
preferably 0.001 to 15 parts by mass, more preferably 0.01 to 10
parts by mass, and still more preferably 0.05 to 5 parts by mass
for 100 parts by mass of the resin (A). If the amount of the acid
diffusion controllers exceeds 15 parts by mass, sensitivity as a
resist may decrease. If the amount is less than 0.001 part by mass,
the pattern configuration or dimensional accuracy as a resist may
decrease depending on the processing conditions.
[0230] The alicyclic additives further improve dry etching
tolerance, pattern shape, and adhesion to substrate.
[0231] As examples of such alicyclic additives, adamantane
derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone,
t-butyl 1-adamantanecarboxylate, t-butoxycarbonylmethyl
1-adamantanecarboxylate, .alpha.-butyrolactone
1-adamantanecarboxylate, di-t-butyl 1,3-adamantanedicarboxylate,
t-butyl 1-adamantaneacetate, t-butoxycarbonylmethyl
1-adamantaneacetate, di-t-butyl 1,3-adamantanediacetate, and
2,5-dimethyl-2,5-di(adamantylcarbonyloxy)hexane; deoxycholates such
as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholate,
2-ethoxyethyl deoxycholate, 2-cyclohexyloxyethyl deoxycholate,
3-oxocyclohexyl deoxycholate, tetrahydropyranyl deoxycholate, and
mevalonolactone deoxycholate; lithocholates such as t-butyl
lithocholate, t-butoxycarbonylmethyl lithocholate, 2-ethoxyethyl
lithocholate, 2-cyclohexyloxyethyl lithocholate, 3-oxocyclohexyl
lithocholate, tetrahydropyranyl lithocholate, and mevalonolactone
lithocholate; alkyl carboxylates such as dimethyl adipate, diethyl
adipate, dipropyl adipate, di-n-butyl adipate, and di-t-butyl
adipate;
3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4.4.0.1.sup.2,5.1.s-
up.7,10]dodecane can be given. These alicyclic additives may be
used either individually or in combination of two or more.
[0232] Surfactants improve applicability, striation,
developability, and the like.
[0233] As the surfactants, nonionic surfactants such as
polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,
polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether,
polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate,
and polyethylene glycol distearate; commercially available products
such as "KP341" (manufactured by Shin-Etsu Chemical Co., Ltd.),
"Polyflow No. 75" and "Polyflow No. 95" (manufactured by Kyoeisha
Chemical Co., Ltd.), "EFTOP EF301", "EFTOP EF303", and "EFTOP
EF352" (manufactured by JEMCO, Inc.), "MEGAFAC F171" and "MEGAFAC
F173" (manufactured by Dainippon Ink and Chemicals, Inc.), "Fluorad
FC430" and "Fluorad FC431" (manufactured by Sumitomo 3M Ltd.),
"Asahi Guard AG710", "Surflon S-382", "Surflon SC-101", "Surflon
SC-102", "Surflon SC-103", "Surflon SC-104", "Surflon SC-105", and
"Surflon SC-106" (manufactured by Asahi Glass Co., Ltd.), and the
like can be given. These surfactants may be used either
individually or in combination of two or more.
[0234] The sensitizers absorb radiation energy and transmit the
energy to the acid generator, thereby increasing the amount of an
acid to be generated upon exposure. The sensitizers improve
apparent sensitivity of the resin composition.
[0235] As examples of the sensitizer, carbazoles, acetophenones,
benzophenones, naphthalenes, phenols, biacetyl, eosine, rose
bengal, pyrenes, anthracenes, phenothiazines, and the like can be
given. These sensitizers may be used either individually or in
combination of two or more.
[0236] As other additives, an alkali-soluble resin, low molecular
weight alkali solubility controllers containing acid dissociable
protecting group, halation inhibitors, preservation stabilizers,
antifoaming agents, and the like can be given. Addition of a dye or
a pigment visualizes a latent image in the exposed area, thereby
decreasing the effects of halation during exposure. Use of an
adhesion improver improves adhesion to the substrates.
[3] Positive-Working Radiation-Sensitive Resin Composition for
Forming Second Resist Layer
[0237] A resin composition comprising (a) a resin which becomes
alkali-soluble by the action of an acid and (b) a solvent is used
for forming the second resist layer in the resist pattern forming
method of the present invention.
<Resin (a) Which Becomes Alkali-Soluble by Action of
Acid>
[0238] The resin (a) which becomes alkali-soluble by action of acid
is a resin insoluble or scarcely soluble in alkali, but becomes
alkali-soluble by the action of an acid. The term
"alkali-insoluble" or "scarcely alkali-soluble" refers to
properties in which 50% or more of the initial thickness of the
resist film remains after development, in the case of developing a
film using only the resin (a) instead of a resist film under
alkaline development conditions employed when forming a resist
pattern of the resist film formed from the second resist layer
forming resin composition containing the resin (a).
[0239] Although any resins which becomes soluble in alkali by the
action of an acid can be used as the resin (a) without a particular
limitation, a resin containing a repeating unit shown by the
formula (14) (hereinafter referred to from time to time as
"repeating unit (14)") and a repeating unit having a skeleton shown
by the above-mentioned formula (3) which becomes soluble in alkali
by the action of an acid is preferable when a positive-working
radiation-sensitive composition containing the crosslinking agent
(A) is used. There no particular limitations when a
positive-working radiation-sensitive composition in which the
polymer (B2) having a crosslinking group and an acid-unstable group
is used.
##STR00030##
wherein R.sup.30 represents a hydrogen atom, a methyl group, or a
trifluoromethyl group, and R.sup.31 represents a single bond, a
methylene group, a linear or branched alkylene group having 2 to 6
carbon atoms, or an alicyclic alkylene group having 4 to 12 carbon
atoms.
[0240] R.sup.31 in the formula (14), which represents a single
bond, a methylene group, a linear or branched alkylene group having
2 to 6 carbon atoms, or an alicyclic alkylene group having 4 to 12
carbon atoms, may be an alkylene glycol group or an alkylene ester
group.
[0241] As preferable examples of R.sup.31, saturated chain
hydrocarbon groups such as a methylene group, an ethylene group, a
propylene group (e.g., a 1,3-propylene group, a 1,2-propylene
group), a tetramethylene group, a pentamethylene group, a
hexamethylene group, a 1-methyl-1,3-propylene group, a
2-methyl-1,3-propylene group, a 2-methyl-1,2-propylene group, a
1-methyl-1,4-butylene group, a 2-methyl-1,4-butylene group, a
methylidene group, an ethylidene group, a propylidene group, and a
2-propylidene group; monocyclic hydrocarbon groups such as
cyclobutylene groups (e.g., a 1,3-cyclobutylene group),
cyclopentylene groups (e.g., a 1,3-cyclopentylene group),
cyclohexylene groups (e.g., 1,4-cyclohexylene group), and
cyclooctylene groups (e.g., 1,5-cyclooctylene group); bridged
cyclic hydrocarbon groups such as cyclic hydrocarbon groups with 2
to 4 rings having 4 to 12 carbon atoms such as norbornylene groups
(e.g., 1,4-norbornylene group, 2,5-norbornylene group), and
admantylene groups (e.g., 1,5-admantylene group, 2,6-admantylene
group); and the like can be given.
[0242] Among these, a hydrocarbon group having a 2,5-norbornylene
group, a 1,2-ethylene group, and a propylene group are preferable
as R.sup.31.
[0243] When the R.sup.31 includes a divalent alicyclic hydrocarbon
group, it is preferable to insert an alkylene group having 1 to 4
carbon atoms as a spacer between the
bis(trifluoromethyl)hydroxymethyl group and the alicyclic
hydrocarbon group.
[0244] As preferable examples of the monomer providing the
repeating unit (14), [0245]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl)(meth)acrylate,
[0246]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl)(meth)acrylat-
e, [0247]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl)(meth)acry-
late, [0248]
(1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl)(meth)acrylate,
[0249]
2-{[5-(1',1',1'-trifluoro-2'-trifluoromethyl-2'-hydroxy)propyl]bic-
yclo[2.2.1]heptyl}(meth)acrylate, [0250]
3-{[8-(1',1',1'-trifluoro-2'-trifluoromethyl-2'-hydroxy)propyl]tetracyclo-
[6.2.1.1.sup.3,6.0.sup.2,7]dodecyl}(meth)acrylate, and the like can
be given.
[0251] The resin (a) may contain only one type of repeating unit
(14) or two or more types of repeating units (14).
[0252] The resin (a) used in the second resist layer forming resin
composition may comprise repeating units other than the
above-mentioned repeating unit (14) or the repeating unit (3).
[0253] As examples of the other repeating units, the
above-mentioned repeating units (4-1) to (7), the repeating unit
(15), and the like which are used in the first resist layer forming
resin composition can be given.
[0254] The content of the repeating unit (14) in the resin (a) for
the second resist layer forming resin composition is preferably 30
to 90 mol %, more preferably 30 to 80 mol %, and still more
preferably 40 to 80 mol % for 100 mol % of all the repeating units
contained in the resin (a). If the content of the repeating unit
(14) is less than 30 mol %, solubility of the resin in the
alcoholic solvent may decrease. If more than 90 mol %, resolution
of the resist film may decrease.
[0255] The content of the repeating unit (3) is preferably 10 to 70
mol %, more preferably 10 to 60 mol %, and still more preferably 20
to 60 mol % for 100 mol % of all the repeating units in the resin
(a). If the content of the repeating unit (3) is less than 10 mol
%, resolution as a resist may decrease. If more than 70 mol %, the
developability of the resist film may decrease.
[0256] The content of the repeating units (4-1) to (4-6) is
preferably not more than 50 mol %, more preferably not more than 40
mol %, and still more preferably not more than 35 mol % for 100 mol
% of all the repeating units in the resin (a). If the content of
the repeating units (4-1) to (4-6) exceeds 50 mol %, solubility in
alcohol solvents may decrease.
[0257] The content of the repeating unit (5) is preferably not more
than 30 mol %, and more preferably not more than 25 mol % of 100
mol % of all the repeating units contained in the resin (a). If the
content of the repeating unit (5) is more than 30 mol %, the resist
film produced tends to swell in an alkali developer and solubility
in an alkali developer may decrease.
[0258] The content of the repeating unit (6) is preferably not more
than 30 mol %, and more preferably not more than 25 mol % of 100
mol % of all the repeating units contained in the resin (a). If the
content of the repeating unit (6) is more than 30 mol %, the resist
film produced tends to swell in an alkali developer and solubility
in an alkali developer may decrease.
[0259] The content of the repeating unit (7) is preferably not more
than 30 mol %, and more preferably not more than 25 mol % of 100
mol % of all the repeating units contained in the resin (a). If the
content of the repeating unit (7) is more than 30 mol %, the resist
film produced tends to swell in an alkali developer and solubility
in an alkali developer may decrease.
[0260] The content of the repeating unit (15) is preferably not
more than 30 mol %, and more preferably not more than 25 mol % of
100 mol % of all the repeating units contained in the resin (a). If
the content of the repeating unit (15) is more than 30 mol %, the
resist film produced tends to swell in an alkali developer and
solubility in an alkali developer may decrease.
[0261] The amount of the other repeating units (the total of other
than the repeating unit (14) and repeating unit (3)) is preferably
not more than 50 mol %, and more preferably not more than 40 mol %
of the total amount of the all the repeating units in the resin
(a).
[0262] The second resist layer forming resin composition may
contain only one type of the resin (a) or may contain two or more
of types of the resin (a).
[0263] The resin (a) can be prepared by, for example, polymerizing
polymerizable unsaturated monomers for constituting each of the
above repeating units in the same manner as in the preparation of
the resin (A) mentioned above.
[0264] Although not particularly limited, the polystyrene-reduced
weight average molecular weight (hereinafter referred to from time
to time as "Mw") of the resin (a) determined by gel permeation
chromatography (GPC) is preferably 1000 to 100,000, more preferably
1000 to 30,000, and still more preferably 1000 to 20,000. If the Mw
of the resin (a) is less than 1000, the heat resistance of the
resist film may decrease. If the Mw of the resin is more than
100,000, the developability of the resist film may decrease. The
ratio of Mw to the polystyrene-reduced number average molecular
weight (hereinafter referred to time to time as "Mn") determined by
GPC (Mw/Mn) of the resin (a) is usually 1 to 5, and preferably 1 to
3.
[0265] The resin (a) may contain low molecular weight components
originating from the monomers used when preparing the resin. The
amount of the low molecular weight components in the resin (a) is
preferably not more than 0.1 mass %, more preferably not more than
0.07 mass %, and still more preferably not more than 0.05 mass %
for 100 mass % (reduced to solid components) of the resin (a). When
this content is not more than 0.1 mass %, the amount of elusion in
the liquid for liquid immersion lithography such as water with
which the resist film comes in contact during exposure can be
reduced. In addition, it is possible to prevent generation of
extraneous substances in the resist during storage, inhibit uneven
resist application, and sufficiently suppress production of defects
during pattern formation.
[0266] It is preferable that the resin (a) contain only a small
amount of impurities such as halogens and metals. The sensitivity,
resolution, process stability, pattern shape, and the like of
formed resist film can be improved by reducing such impurities.
[0267] The following methods can be given as methods for purifying
the resin (a).
<Solvent (b)>
[0268] As the solvent (b), a solvent not dissolving the first
resist pattern which is formed in the resist pattern forming method
of the present invention is preferably used when the
positive-working radiation-sensitive resin composition containing
the crosslinking agent (A) is used. That is, it is desirable to
select the solvent which is mixed with the first resist pattern
only with difficulty. There is no particular limitations when a
positive-working radiation-sensitive composition in which the
polymer (B2) having a crosslinking group and an acid-unstable group
is used.
[0269] As the solvent (b) which is mixed with the first resist
pattern only with difficulty, alcohol solvents are preferable. The
alcoholic solvent refers to (1) a solvent consisting of an alcohol
solvent or (2) a solvent consisting of an alcohol solvent and other
solvent.
[0270] As examples of the alcohol solvent, 1-butyl alcohol, 2-butyl
alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol,
2-pentanol, 3-pentanol, tert-amyl alcohol, neopentyl alcohol,
2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol,
cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol,
2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol,
3,3-dimethyl-2-butanol, 2-diethyl-1-butanol, 2-methyl-1-pentanol,
2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,
3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,
4-methyl-2-pentanol, 4-methyl-3-pentanol, and cyclohexanol can be
given.
[0271] Examples of the other solvents include diethyl ether,
dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl
ether, butyl propyl ether, dibutyl ether, diisobutyl ether,
tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl
ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether,
dihexyl ether, dioctyl ether, cyclopentyl methyl ether, cyclohexyl
methyl ether, cyclododecyl methyl ether, cyclopentyl ethyl ether,
cyclohexyl ethyl ether, cyclopentyl propyl ether,
cyclopentyl-2-propyl ether, cyclohexyl propyl ether,
cyclohexyl-2-propyl ether, cyclopentyl butyl ether,
cyclopentyl-tert-butyl ether, cyclohexyl butyl ether,
cyclohexyl-tert-butyl ether, bromomethyl methyl ether, iodomethyl
methyl ether, .alpha.,.alpha.-dichloromethyl methyl ether,
chloromethyl ethyl ether, 2-chloroethyl methyl ether, 2-bromoethyl
methyl ether, 2,2-dichloro ethyl methyl ether, 2-chloroethyl ethyl
ether, 2-bromoethyl ethyl ether,(.+-.)-1,2-dichloroethyl ethyl
ether, di-2-bromoethyl ether, 2,2,2-trifluoroethyl ether,
chloromethyl octyl ether, bromomethyl octyl ether, di-2-chloroethyl
ether, ethyl vinyl ether, butyl vinyl ether, allylethyl ether,
allyl propyl ether, allyl butyl ether, diallyl ether,
2-methoxypropene, ethyl-1-propenyl ether, 1-methoxy-1,3-butadiene,
cis-1-bromo-2-ethoxyethylene, 2-chloroethyl vinyl ether, and
allyl-1,1,2,2-tetrafluoro ethyl ether.
[0272] Among these, preferable ethers are dipropyl ether,
diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl
propyl ether, dibutyl ether, diisobutyl ether, tert-butyl-methyl
ether, tert-butyl ethyl ether, tert-butyl propyl ether,
di-tert-butyl ether, dipentyl ether, diisoamyl ether, cyclopentyl
methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether,
cyclohexyl ethyl ether, cyclopentyl propyl ether,
cyclopentyl-2-propyl ether, cyclohexyl propyl ether,
cyclohexyl-2-propyl ether, cyclopentyl butyl ether,
cyclopentyl-tert-butyl ether, cyclohexyl butyl ether, and
cyclohexyl-tert-butyl ether. In addition, octane, isooctane,
nonane, decane, methylcyclohexane, decalin, xylene, amyl benzene,
ethylbenzene diethyl benzene, cumene, sec-butylbenzene, cymene, and
a dipentene are preferable.
[0273] When the solvent (b) contains the other solvents, the
proportion of the other solvents is usually 60 mass % or less,
preferably 50 mass % or less, and still more preferably 40 mass %
or less of 100 mass % of the solvent (b).
[0274] These solvents (b) may be used either individually or in
combinations of two or more.
[0275] The second resist layer forming resin composition is usually
used in the form of a composition solution prepared by dissolving
the composition in the solvent (b) so that the total solid content
is usually 1 to 50 mass %, and preferably 1 to 25 mass %, and
thereafter filtering the solution using a filter with a pore
diameter of about 0.2 .mu.m, for example.
<Radiation-Sensitive Acid Generator>
[0276] A radiation-sensitive acid generator is usually added to the
second resist layer forming resin composition.
[0277] The above description concerning the acid generator in the
first resist layer forming resin composition can be applied as is
to the acid generator. The acid generator added to the first resist
layer forming resin composition and the second resist layer forming
resin composition may be either the same or different.
[0278] The total amount of the acid generator 1 and aforementioned
other acid generators is usually 0.1 to 20 parts by mass, and
preferably 0.5 to 10 parts by mass for 100 parts by mass of the
resin (a) from the viewpoint of ensuring sensitivity and
developability as a resist. If this total amount is less than 0.1
part by mass, the sensitivity and developability tend to be
impaired. If this total amount is more than 20 parts by mass, the
transparency of the resist to radiation tends to decrease, which
makes it difficult to obtain a rectangular resist pattern.
[0279] The proportion of the other acid generators to be added is
80 mass % or less, and preferably 60 mass % or less of the total
amount of 100 mass % of acid generators (acid generator 1 and other
acid generators) used.
<Additives>
[0280] Additives may be added to the second resist layer forming
resin composition. The above description of various additives used
in the first resist layer forming resin composition such as acid
diffusion controller can be applied as is to the each kinds of
additives.
[0281] When the acid diffusion controller is added, the amount of
the acid diffusion controller is preferably 0.001 to 15 parts by
mass, more preferably 0.01 to 10 parts by mass, and still more
preferably 0.05 to 5 parts by mass for 100 parts by mass of the
resin (a). If the amount of the acid diffusion controllers exceeds
15 parts by mass, sensitivity as a resist may decrease. If the
amount is less than 0.001 parts by mass, the pattern configuration
or dimensional accuracy as a resist may decrease depending on the
processing conditions.
EXAMPLES
[0282] Embodiments of the present invention are described below in
detail by examples. However, these examples should not be construed
as limiting the present invention. In the examples, "part" refers
to "part by mass" unless otherwise indicated.
[Case in Which Positive-Working Radiation-Sensitive Composition
Containing Crosslinking Agent (A) is Used]
Example 1
Preparation of First Resist Layer Forming Radiation-Sensitive Resin
Composition
[0283] 15 parts by mass of 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,
3H, 5H)-trione as the crosslinking agent (A), 3.0 parts by mass of
triphenylsulfonium nonafluoro-n-butanesulfonate as the
radiation-sensitive acid generator (C), 0.34 parts by mass of
N-t-butoxycarbonylpyrrolidine as the acid diffusion controller (D),
960 parts by mass of cyclohexanone as a main solvent, and 410 parts
by mass of propylene glycol monomethyl ether acetate as a
subsolvent were added to 100 parts by mass of the polymer of the
following formula (B-1) as the resin (B). These components were
mixed to obtain a homogeneous solution. The solution was filtered
through a membrane filter with a pore diameter of 200 nm to obtain
a coating solution of a radiation-sensitive resin composition
(total solid content: about 7 mass %).
##STR00031##
Comparative Example 1
Preparation of First Resist Layer Forming Radiation-Sensitive Resin
Composition
[0284] 3.0 parts by mass of triphenylsulfonium
nonafluoro-n-butanesulfonate as the radiation-sensitive acid
generator (C), 0.34 parts by mass of N-t-butoxycarbonylpyrrolidine
as the acid diffusion controller (D), 960 parts by mass of
cyclohexanone as a main solvent, and 410 parts by mass of propylene
glycol monomethyl ether acetate as a subsolvent were added to 100
parts by mass of the polymer of the above formula (B-1) as the
resin (B). These components were mixed to obtain a homogeneous
solution. The solution was filtered through a membrane filter with
a pore diameter of 200 nm to obtain a coating solution of a
radiation-sensitive resin composition (total solid content: about 7
mass %).
[0285] Measurement and evaluation of the resulting
radiation-sensitive resin compositions were carried out according
to the following procedures.
(1) Measurement of Characteristic Curve:
[0286] Using a CLEAN TRACK ACTS (manufactured by Tokyo Electron,
Ltd.), the radiation-sensitive resin composition was spin-coated on
a silicon substrate and baked (PB) at 80.degree. C. for 60 seconds
to obtain a resist film with a thickness of 150 nm. The resist film
was exposed to radiation through quartz not having a pattern using
an ArF excimer laser exposure apparatus ("NSR S306C" manufactured
by Nicon Corp., exposure conditions: NA 0.75 sigma 0.85). After PEB
at 130.degree. C. for 60 seconds, the resist coating was developed
at 23.degree. C. for 30 seconds in a 2.38 mass %
tetramethylammonium hydroxide aqueous solution, washed with water,
and dried to obtain a wafer for measuring a characteristic curve.
The film thickness was measured at various exposure doses using an
automatic thickness meter ("VM-2010" manufactured by Dainippon
Screen Mfg. Co., Ltd.) to confirm the correlation between the
exposure dose and the film thickness. The results are shown in FIG.
4.
[0287] As clear from the characteristic curve measurement shown in
FIG. 4, the radiation sensitive resin composition for liquid
immersion lithography of the present invention was confirmed to
function as a positive-working resist and a negative-working resist
responding to a certain amount of radiation at 193 nm.
Specifically, the resin composition can form a positive-working
resist pattern at a low exposure dose, of which the pattern is
converted into negative-working at a dose of several times the
optimum dose and can be expected to be inactivated when forming a
second resist pattern. In the resist pattern forming method
proposed by the present invention in which this resin composition
is used, it is possible to make the first resist pattern inactive
when the second resist pattern is formed by exposing the first
resist pattern to radiation at a dose several times the optimum
dose for forming the first resist pattern and heating the exposed
resist pattern, whereby it is possible to form a desired
pattern.
Case in which Positive-Working Radiation-Sensitive Composition
Using Polymer (B2) having Crosslinking Group and Acid-Unstable
Group is Used
Examples 2 to 13
Preparation of First Resist Layer Forming Radiation-Sensitive
Compositions
[0288] 7.5 parts by mass of triphenylsulfonium
nonafluoro-n-butanesulfonate (C-1) as the radiation-sensitive acid
generator (C), 0.94 parts by mass of N-t-butoxycarbonylpyrrolidine
(D-1) as the acid diffusion controller (D), 1287 parts by mass of
propylene glycol monomethyl ether acetate (E-1) as a main solvent,
and 551 parts by mass of cyclohexanone (E-2) as a subsolvent were
added to a mixture of 80 parts by mass of the polymer of the
following formula (B-2) and 20 parts by mass of one of the
following polymers (B-3) to (B-6) or (B-11) to (B-14) or 100 parts
by mass of one of the following polymers (B-7) to (B-10), as the
resin (B). These components were mixed to obtain homogeneous
solutions. The solutions were filtered through a membrane filter
with a pore diameter of 200 nm to obtain the radiation-sensitive
composition coating solutions (total solid content: about 7 mass %)
shown in Table 1.
TABLE-US-00001 TABLE 1 ##STR00032## ##STR00033## ##STR00034##
##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039##
##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044##
Polymer (B) Polymer (B) Acid generator Nitrogen-containing Solvent
(E) (part) (part) (C) (part) compound (D) (part) (part) Example 2
B-2 (80) B-3 (20) C-1 (7.5) D-1 (0.94) E-1 (1287) E-2 (551) Example
3 B-2 (80) B-4 (20) C-1 (7.5) D-1 (0.94) E-1 (1287) E-2 (551)
Example 4 B-2 (80) B-5 (20) C-1 (7.5) D-1 (0.94) E-1 (1287) E-2
(551) Example 5 B-2 (80) B-6 (20) C-1 (7.5) D-1 (0.94) E-1 (1287)
E-2 (551) Example 6 -- B-7 (100) C-1 (7.5) D-1 (0.94) E-1 (1287)
E-2 (551) Example 7 -- B-8 (100) C-1 (7.5) D-1 (0.94) E-1 (1287)
E-2 (551) Example 8 -- B-9 (100) C-1 (7.5) D-1 (0.94) E-1 (1287)
E-2 (551) Example 9 -- B-10 (100) C-1 (7.5) D-1 (0.94) E-1 (1287)
E-2 (551) Example 10 B-2 (80) B-11 (20) C-1 (7.5) D-1 (0.94) E-1
(1287) E-2 (551) Example 11 B-2 (80) B-12 (20) C-1 (7.5) D-1 (0.94)
E-1 (1287) E-2 (551) Example 12 B-2 (80) B-13 (20) C-1 (7.5) D-1
(0.94) E-1 (1287) E-2 (551) Example 13 B-2 (80) B-14 (20) C-1 (7.5)
D-1 (0.94) E-1 (1287) E-2 (551) Comparative B-1 (100) -- C-1 (7.5)
D-1 (0.94) E-1 (1287) Example 1 E-2 (551)
[Preparation of Second Resist Layer Forming Radiation-Sensitive
Resin Composition]
[0289] 7.0 parts by mass of triphenylsulfonium
nonafluoro-n-butanesulfonate as the radiation-sensitive acid
generator (C), 2.64 parts by mass of the compound shown by the
following formula (D2) as the acid diffusion controller (D), and
2014 parts by mass of propylene glycol monomethyl ether acetate as
a main solvent were added to 100 parts by mass of the polymer of
the following formula (B-15) as the resin (a). These components
were mixed to obtain a homogeneous solution. The solutions were
filtered through a membrane filter with a pore diameter of 200 nm
to obtain radiation-sensitive composition coating solutions (total
solid content: about 6.5 mass %).
##STR00045##
(1) Double Patterning (DP) Formation and Evaluation
[0290] Double patterns were formed from the first resist and second
resist according to the following steps (i) to (iii). (i) First
resist pattern formation, (ii) baking at 200.degree. C. for 90
seconds, (iii) second resist pattern formation
[0291] (i) A coated film with a thickness of 77 nm was formed on an
8 inch silicon wafer by spin coating a lower layer antireflection
film ("ARC29A" manufactured by Brewer Science) using a "CLEAN TRACK
ACT8" (manufactured by Tokyo Electron Ltd.) and baking (PB,
205.degree. C., 60 seconds). The first resist agent was spin coated
using the "CLEAN TRACK ACT8", baked (PB, 130.degree. C., 60
seconds), and cooled (23.degree. C., 30 seconds) to obtain a coated
film with a thickness of 150 nm. Next, the film was exposed to
radiation using an ArF exposure apparatus ("S306C" manufactured by
NIKON) under the optical conditions of NA: 0.78 and outer/inner=2/3
annular through a mask with a mask size of 105 nm line/262.5 nm
pitch. After PEB (125.degree. C. for 60 seconds) on a hot plate of
a "CLEAN TRACK ACT8" and cooling (23.degree. C., 30 seconds), the
exposed resist was developed by paddle development (30 seconds)
using a developing cup LD nozzle and 2.38 mass % TMAH aqueous
solution, and washed with ultra pure water. An evaluation substrate
A on which a first resist pattern was formed was obtained by
centrifugation at 2000 rpm for 15 seconds.
[0292] (ii) The first resist pattern of the resulting substrate A
for evaluation was baked (PEB: 200.degree. C., 90 seconds) on a
"CLEAN TRACK ACT8" hot plate to obtain an evaluation substrate B on
which an insolubilized resist pattern was formed.
[0293] (iii) The second resist agent ("CLEAN TRACK ACT8") was spin
coated on the insolubilized resist pattern of the evaluation
substrate B obtained in (ii) above, the coating was baked (PB,
100.degree. C., 60 seconds) and cooled (23.degree. C., 30 seconds)
to obtain a coated film with a thickness of 120 nm. The space area
of the insolubilized resist pattern was exposed to radiation using
an ArF exposure apparatus ("S306C" manufactured by NIKON) under the
optical conditions of NA: 0.78 and outer/inner=2/3 annular through
a mask with a mask size of 130 nm line/260 nm pitch. After PEB
(110.degree. C. for 60 seconds) on a hot plate of a "CLEAN TRACK
ACTS" and cooling (23.degree. C., 30 seconds), the exposed resist
was developed by paddle development (30 seconds) using a developing
cup LD nozzle and 2.38 mass % TMAH aqueous solution, and washed
with ultra pure water. An evaluation substrate C on which a second
resist pattern was formed was obtained by centrifugal drying at
2000 rpm for 15 seconds.
[0294] The results after the steps (i) and (ii) were evaluated as
"Bad" if the first resist pattern was lost or unresolved and as
"Good" if DP was formed and resolved without top loss scum. The
step conditions and results are shown in Table 2. As a Comparative
Example, B-2 (100 parts by mass) was used as a polymer.
TABLE-US-00002 TABLE 2 Step (i) Step (ii) Step (iii) Bake
(temp/time) PEB (temp/time) PEB (temp/time) Bake (temp/time) PEB
(temp/time) (.degree. C./s) (.degree. C./s) (.degree. C./s)
(.degree. C./s) (.degree. C./s) DP pattern Example 2 130/60 125/60
200/90 100/60 110/60 Good Example 3 130/60 125/60 200/90 100/60
110/60 Good Example 4 130/60 125/60 200/90 100/60 110/60 Good
Example 5 130/60 125/60 200/90 100/60 110/60 Good Example 6 130/60
125/60 200/90 100/60 110/60 Good Example 7 130/60 125/60 200/90
100/60 110/60 Good Example 8 130/60 125/60 200/90 100/60 110/60
Good Example 9 130/60 125/60 200/90 100/60 110/60 Good Example 10
130/60 125/60 200/90 100/60 110/60 Good Example 11 130/60 125/60
200/90 100/60 110/60 Good Example 12 130/60 125/60 200/90 100/60
110/60 Good Example 13 130/60 125/60 200/90 100/60 110/60 Good
Comparative 130/60 125/60 200/90 100/60 110/60 Bad Example 1
INDUSTRIAL APPLICABILITY
[0295] Since a good pattern surpassing a wavelength limit can be
economically formed according to the resist pattern forming method
in which the positive-working radiation-sensitive resin composition
of the present invention is used, the method of the present
invention can be used very suitably in the field of
microfabrication represented by production of integrated circuit
elements which are expected to become increasingly micronized in
the future.
* * * * *