U.S. patent application number 13/825925 was filed with the patent office on 2013-07-25 for resist underlayer film forming composition for lithography containing polyether structure-containing resin.
This patent application is currently assigned to NISSAN CHEMICAL INDUSTRIES, LTD.. The applicant listed for this patent is Keisuke Hashimoto, Masakazu Kato, Hiroaki Okuyama, Tetsuya Shinjo, Yasunobu Someya. Invention is credited to Keisuke Hashimoto, Masakazu Kato, Hiroaki Okuyama, Tetsuya Shinjo, Yasunobu Someya.
Application Number | 20130189533 13/825925 |
Document ID | / |
Family ID | 45938293 |
Filed Date | 2013-07-25 |
United States Patent
Application |
20130189533 |
Kind Code |
A1 |
Okuyama; Hiroaki ; et
al. |
July 25, 2013 |
RESIST UNDERLAYER FILM FORMING COMPOSITION FOR LITHOGRAPHY
CONTAINING POLYETHER STRUCTURE-CONTAINING RESIN
Abstract
There is provided a resist underlayer film forming composition
for forming a resist underlayer film providing heat resistance
properties and hardmask characteristics. A resist underlayer film
forming composition for lithography, comprising: a polymer
containing a unit structure of Formula (1): O--Ar.sub.1 Formula (1)
(in Formula (1), Ar.sub.1 is a C.sub.6-50 arylene group or an
organic group containing a heterocyclic group), a unit structure of
Formula (2): O--Ar.sub.2--O--Ar.sub.3-T-Ar.sub.4 Formula (2) (in
Formula (2), Ar.sub.2, Ar.sub.3, and Ar.sub.4 are individually a
C.sub.6-50 arylene group or an organic group containing a
heterocyclic group; and T is a carbonyl group or a sulfonyl group),
or a combination of the unit structure of Formula (1) and the unit
structure of Formula (2). The organic groups of Ar.sub.1 and
Ar.sub.2 containing arylene group may be organic groups containing
a fluorene structure.
Inventors: |
Okuyama; Hiroaki;
(Toyama-shi, JP) ; Someya; Yasunobu; (Toyama-shi,
JP) ; Kato; Masakazu; (Toyama-shi, JP) ;
Shinjo; Tetsuya; (Toyama-shi, JP) ; Hashimoto;
Keisuke; (Toyama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Okuyama; Hiroaki
Someya; Yasunobu
Kato; Masakazu
Shinjo; Tetsuya
Hashimoto; Keisuke |
Toyama-shi
Toyama-shi
Toyama-shi
Toyama-shi
Toyama-shi |
|
JP
JP
JP
JP
JP |
|
|
Assignee: |
NISSAN CHEMICAL INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
45938293 |
Appl. No.: |
13/825925 |
Filed: |
October 7, 2011 |
PCT Filed: |
October 7, 2011 |
PCT NO: |
PCT/JP2011/073233 |
371 Date: |
April 10, 2013 |
Current U.S.
Class: |
428/524 ;
438/703; 438/781; 524/544; 524/592; 524/611 |
Current CPC
Class: |
C08L 71/00 20130101;
G03F 7/2059 20130101; Y10T 428/31942 20150401; G03F 7/091 20130101;
G03F 7/11 20130101; H01L 21/308 20130101; C09D 171/00 20130101;
H01L 21/3086 20130101; G03F 7/32 20130101; G03F 7/094 20130101;
C08G 65/4006 20130101; C08G 2650/40 20130101; C08G 65/4012
20130101 |
Class at
Publication: |
428/524 ;
438/703; 524/592; 524/544; 524/611; 438/781 |
International
Class: |
G03F 7/09 20060101
G03F007/09; H01L 21/308 20060101 H01L021/308 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2010 |
JP |
2010-231217 |
Claims
1. A resist underlayer film forming composition for lithography,
comprising: a polymer containing a unit structure of Formula (1):
O--Ar.sub.1 Formula (1) (in Formula (1), Ar.sub.1 is a C.sub.6-50
arylene group or an organic group containing a heterocyclic group),
a unit structure of Formula (2):
O--Ar.sub.2--O--Ar.sub.3-T-Ar.sub.4 Formula (2) (in Formula (2),
Ar.sub.2, Ar.sub.3, and Ar.sub.4 are individually a C.sub.6-50
arylene group or an organic group containing a heterocyclic group;
and T is a carbonyl group or a sulfonyl group), or a combination of
the unit structure of Formula (1) and the unit structure of Formula
(2).
2. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (1), and the organic group of Ar.sub.1 is an organic group
containing a fluorene structure.
3. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (2), and the organic group of Ar.sub.2 is an organic group
containing a fluorene structure.
4. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing a combination of the unit
structure of Formula (1) and the unit structure of Formula (2), and
at least one of the organic group of Ar.sub.1 and the organic group
of Ar.sub.2 is an organic group containing a fluorene
structure.
5. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (1), and the organic group of Ar.sub.1 is an organic group
containing a combination of an arylene group with a group
containing a carbon-carbon triple bond and/or a group containing a
carbon-carbon double bond.
6. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (2), and the organic group of Ar.sub.2 is an organic group
containing a combination of an arylene group with a group
containing a carbon-carbon triple bond and/or a group containing a
carbon-carbon double bond.
7. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing a combination of the unit
structure of Formula (1) and the unit structure of Formula (2), and
at least one of the organic group of Ar.sub.1 and the organic group
of Ar.sub.2 is an organic group containing a combination of an
arylene group with a group containing a carbon-carbon triple bond
and/or a group containing a carbon-carbon double bond.
8. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (1), and the organic group of Ar.sub.1 is an organic group
containing a biphenylene structure.
9. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (2), and the organic group of Ar.sub.2 is an organic group
containing a biphenylene structure.
10. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing a combination of the unit
structure of Formula (1) and the unit structure of Formula (2), and
at least one of the organic group of Ar.sub.1 and the organic group
of Ar.sub.2 is an organic group containing a biphenylene
structure.
11. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing the unit structure of
Formula (2), and at least one of the organic group of Ar.sub.3 and
the organic group of Ar.sub.4 is a phenylene group.
12. The resist underlayer film forming composition according to
claim 1, wherein the resist underlayer film forming composition for
lithography contains a polymer containing a combination of the unit
structure of Formula (1) and the unit structure of Formula (2), and
at least one of the organic group of Ar.sub.3 and the organic group
of Ar.sub.4 is a phenylene group.
13. The resist underlayer film forming composition according to
claim 1, further comprising an acid or an acid generator.
14. A resist underlayer film obtained by applying the resist
underlayer film forming composition as claimed in claim 1 onto a
semiconductor substrate and baking the resultant film.
15. A method for producing a semiconductor device, the method
comprising: a process of forming an underlayer film with the resist
underlayer film forming composition as claimed in claim 1 on a
semiconductor substrate; a process of forming a resist film on the
underlayer film; a process of irradiating the resist film with
light or an electron beam and developing the resist film so as to
form a resist pattern; a process of etching the underlayer film
according to the resist pattern of the resist film; and a process
of processing the semiconductor substrate according to the
patterned underlayer film.
16. A method for producing a semiconductor device, the method
comprising: a process of forming an underlayer film with the resist
underlayer film forming composition as claimed in claim 1 on a
semiconductor substrate; a process of forming a hardmask on the
underlayer film; a process of further forming a resist film on the
hardmask; a process of irradiating the resist film with light or an
electron beam and developing the resist film so as to form a resist
pattern; a process of etching the hardmask according to the resist
pattern of the resist film; a process of etching the underlayer
film according to the patterned hardmask; and a process of
processing the semiconductor substrate according to the patterned
underlayer film.
Description
TECHNICAL FIELD
[0001] The present invention relates to a resist underlayer film
forming composition for lithography that is effectively used for
processing of a semiconductor substrate, a resist pattern forming
method employing the resist underlayer film forming composition,
and a method for producing a semiconductor device.
BACKGROUND ART
[0002] Conventionally, in the production of semiconductor devices,
fine processing by lithography using a photoresist composition has
been performed. The fine processing is a processing method
including: forming a thin film of a photoresist composition on a
substrate to be processed such as a silicon wafer; irradiating the
resultant thin film with an active ray such as an ultraviolet ray
through a mask pattern in which a pattern of a semiconductor device
is depicted for development; and etching the substrate to be
processed such as a silicon wafer using the resultant photoresist
pattern as a protecting film. Recently, however, the high
integration of semiconductor devices has progressed and the adopted
active ray tends to have a shorter wavelength, such as an ArF
excimer laser (193 nm) replacing a KrF excimer laser (248 nm).
Following such a tendency, the influence of diffused reflection of
an active ray on a substrate or a standing wave has become a large
problem. To address this, what has been widely studied is the use
of an anti-reflective coating (Bottom Anti-Reflective Coating,
BARC) between the photoresist and the substrate to be
processed.
[0003] Progress in refinement of the resist pattern will cause a
problem of the resolution or collapse of a resist pattern after
development; therefore, thinning of the resist will be required. In
this sense, it is difficult to secure a resist pattern film
thickness sufficient for processing the substrate, which requires a
process for imparting a function as a mask for processing the
substrate not only to the resist pattern, but also to the resist
underlayer film provided between the resist and the semiconductor
substrate to be processed. As a resist underlayer film for such a
process, there have started to be required a resist underlayer film
for lithography having a selection ratio of a dry etching rate
close to that of the resist, a resist underlayer film for
lithography having a selection ratio of a dry etching rate smaller
than that of the resist, and a resist underlayer film for
lithography having a selection ratio of a dry etching rate smaller
than that of the semiconductor substrate, as a resist underlayer
film, unlike a conventional resist underlayer film having high
etching rate property (high etching rate).
[0004] In addition, a heat resistant resist underlayer film having
a fluorene structure is disclosed (Patent Document 1).
PRIOR-ART DOCUMENT
Patent Document
[0005] Patent Document 1: International Publication No. WO
2010/041626 pamphlet
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0006] The present invention provides a resist underlayer film
forming composition for using for a lithography process of the
production of semiconductor devices. It is an object of the present
invention to provide a resist underlayer film for lithography
causing no intermixing with a resist layer, providing an excellent
resist pattern, and having: a selection ratio of a dry etching rate
close to that of the resist; a selection ratio of a dry etching
rate smaller than that of the resist; or a selection ratio of a dry
etching rate smaller than that of the semiconductor substrate. The
present invention also provides a resist underlayer film for
lithography capable of imparting performance of effectively
absorbing light reflected on the substrate when irradiated light
having a wavelength of 248 nm, 193 nm, 157 nm, or the like is used
for fine processing. Furthermore, it is an object of the present
invention to provide a resist pattern forming method using the
resist underlayer film forming composition. Then, the present
invention provides a resist underlayer film forming composition for
forming a resist underlayer film providing heat resistance in
combination with other advantageous properties.
Means for Solving the Problem
[0007] The present invention is, according to a first aspect, a
resist underlayer film forming composition for lithography,
containing a polymer containing a unit structure of Formula
(1):
O--Ar.sub.1 Formula (1)
(in Formula (1), Ar.sub.1 is a C.sub.6-50 arylene group or an
organic group containing a heterocyclic group), a unit structure of
Formula (2):
O--Ar.sub.2--O--Ar.sub.3-T-Ar.sub.4 Formula (2)
(in Formula (2), Ar.sub.2, Ar.sub.3, and Ar.sub.4 are individually
a C.sub.6-50 arylene group or an organic group containing a
heterocyclic group; and T is a carbonyl group or a sulfonyl group),
or a combination of the unit structure of Formula (1) and the unit
structure of Formula (2),
[0008] according to a second aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (1), and the
organic group of Ar.sub.1 is an organic group containing a fluorene
structure,
[0009] according to a third aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (2), and the
organic group of Ar.sub.2 is an organic group containing a fluorene
structure,
[0010] according to a fourth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing a combination of the unit structure of Formula
(1) and the unit structure of Formula (2), and at least one of the
organic group of Ar.sub.1 and the organic group of Ar.sub.2 is an
organic group containing a fluorene structure,
[0011] according to a fifth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (1), and the
organic group of Ar.sub.1 is an organic group containing a
combination of an arylene group with a group containing a
carbon-carbon triple bond and/or a group containing a carbon-carbon
double bond,
[0012] according to a sixth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (2), and the
organic group of Ar.sub.2 is an organic group containing a
combination of an arylene group with a group containing a
carbon-carbon triple bond and/or a group containing a carbon-carbon
double bond,
[0013] according to a seventh aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing a combination of the unit structure of Formula
(1) and the unit structure of Formula (2), and at least one of the
organic group of Ar.sub.1 and the organic group of Ar.sub.2 is an
organic group containing a combination of an arylene group with a
group containing a carbon-carbon triple bond and/or a group
containing a carbon-carbon double bond,
[0014] according to an eighth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (1), and the
organic group of Ar.sub.1 is an organic group containing a
biphenylene structure,
[0015] according to a ninth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (2), and the
organic group of Ar.sub.2 is an organic group containing a
biphenylene structure,
[0016] according to a tenth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing a combination of the unit structure of Formula
(1) and the unit structure of Formula (2), and at least one of the
organic group of Ar.sub.1 and the organic group of Ar.sub.2 is an
organic group containing a biphenylene structure,
[0017] according to an eleventh aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing the unit structure of Formula (2), and at
least one of the organic group of Ar.sub.3 and the organic group of
Ar.sub.4 is a phenylene group,
[0018] according to a twelfth aspect, the resist underlayer film
forming composition according to the first aspect, in which the
resist underlayer film forming composition for lithography contains
a polymer containing a combination of the unit structure of Formula
(1) and the unit structure of Formula (2), and at least one of the
organic group of Ar.sub.3 and the organic group of Ar.sub.4 is a
phenylene group,
[0019] according to a thirteenth aspect, the resist underlayer film
forming composition according to any one of the first aspect to the
twelfth aspect further containing an acid or an acid generator,
[0020] according to a fourteenth aspect, a resist underlayer film
obtained by applying the resist underlayer film forming composition
described in any one of the first aspect to the thirteenth aspect
onto a semiconductor substrate and baking the resultant film,
[0021] according to a fifteenth aspect, a method for producing a
semiconductor device including: a process of forming an underlayer
film with the resist underlayer film forming composition described
in any one of the first aspect to the thirteenth aspect on a
semiconductor substrate; a process of forming a resist film on the
underlayer film; a process of irradiating the resist film with
light or an electron beam and developing the resist film so as to
form a resist pattern; a process of etching the underlayer film
according to the resist pattern of the resist film; and a process
of processing the semiconductor substrate according to the
patterned underlayer film, and
[0022] according to a sixteenth aspect, a method for producing a
semiconductor device including: a process of forming an underlayer
film with the resist underlayer film forming composition described
in any one of the first aspect to the thirteenth aspect on a
semiconductor substrate; a process of forming a hardmask on the
underlayer film; a process of further forming a resist film on the
hardmask; a process of irradiating the resist film with light or an
electron beam and developing the resist film so as to form a resist
pattern; a process of etching the hardmask according to the resist
pattern of the resist film; a process of etching the underlayer
film according to the patterned hardmask; and a process of
processing the semiconductor substrate according to the patterned
underlayer film.
Effect of the Invention
[0023] With the resist underlayer film forming composition of the
present invention, an advantageous pattern shape of a resist can be
formed without causing intermixing with an upper layer of the
resist underlayer film.
[0024] The resist underlayer film forming composition of the
present invention can have performance of effectively suppressing
reflection on the substrate and provide an effect as an
anti-reflective coating for exposure light in combination with
other advantageous properties.
[0025] The resist underlayer film forming composition of the
present invention can provide an excellent resist underlayer film
having a selection ratio of a dry etching rate close to that of the
resist, a selection ratio of a dry etching rate smaller than that
of the resist, or a selection ratio of a dry etching rate smaller
than that of the semiconductor substrate.
[0026] Due to refinement of the resist pattern, for preventing the
resist pattern from collapsing after development, thinning of the
resist is performed. For such a thin film resist, there is a
process including: transferring a resist pattern to an underlayer
film thereof by etching process; and processing the substrate using
the underlayer film as a mask. There is another process in which a
process including transferring a resist pattern to an underlayer
film thereof by etching process and further transferring the
pattern transferred to the underlayer film to an underlayer film
thereof using a gas having a different gas composition is
repeatedly performed so that the substrate is processed. The resist
underlayer film and the forming composition thereof of the present
invention are effective for these processes and when the substrate
is processed using the resist underlayer film of the present
invention, the resist underlayer film has satisfactory etching
resistance relative to the substrate to be processed (for example,
a thermally oxidized silicon film, a nitride silicon film, a
polysilicon film, and the like on the substrate).
[0027] The resist underlayer film of the present invention can be
used as a planarization film, a resist underlayer film, a
contamination preventing film for the resist layer, and a film
having dry etching selectivity. Use of the resist underlayer film
of the present invention makes it possible to easily and accurately
perform the formation of a resist pattern in a lithography process
of the semiconductor production.
[0028] There is a process including: forming a resist underlayer
film with a resist underlayer film forming composition on a
substrate; forming a hardmask on the resist underlayer film;
forming a resist film on the hardmask; forming a resist pattern by
exposure and development; transferring the resist pattern to the
hardmask; transferring the resist pattern transferred to the
hardmask to the resist underlayer film; and processing the
semiconductor substrate according to the resist underlayer film. In
this process, there are a case where the formation of the hardmask
is performed by a coating-type composition containing an organic
polymer or an inorganic polymer and a solvent, and a case where the
formation of the hardmask is performed by vacuum deposition of an
inorganic substance. In vacuum deposition of an inorganic substance
(for example, silicon nitride oxide), a deposited substance is
deposited on the surface of the resist underlayer film and at this
time, the temperature of the surface of the resist underlayer film
is elevated to around 400.degree. C. In the resist underlayer film
forming composition of the present invention, the used polymer is a
copolymer containing a polyether structure, for example, a unit
structure of fluorene naphthol and a unit structure of arylene
alkylene, so that the used polymer has extremely high heat
resistance and is difficult to cause thermal degradation even by
the deposition of the deposited substance.
BEST MODES FOR CARRYING OUT THE INVENTION
[0029] The present invention is a resist underlayer film forming
composition for lithography containing a polymer containing a unit
structure of Formula (1), a unit structure of Formula (2), or a
unit structure containing a combination of these unit
structures.
[0030] The resist underlayer film forming composition may contain a
crosslinking agent, an acid, and if necessary, an additive such as
an acid generator and a surfactant. The solid content of the
composition is 0.1 to 70% by mass or 0.1 to 60% by mass. The solid
content is a content of a component remaining after a solvent is
removed from the resist underlayer film forming composition.
[0031] In the solid content, the above polymer can be contained in
a content of 1 to 100% by mass, 1 to 99% by mass, or 50 to 99% by
mass.
[0032] The polymer used in the present invention has a weight
average molecular weight of 600 to 1,000,000, preferably 1,000 to
200,000.
[0033] The unit structure of Formula (1) is a unit structure having
a polyether structure and the unit structure of Formula (2) is a
unit structure having a polyetheretherketone structure or a
polyetherethersulfon structure.
[0034] In the unit structure of Formula (1), Ar.sub.1 is a
C.sub.6-50 arylene group or an organic group containing a
heterocyclic group. The organic group is, for example, a divalent
to tetravalent group. In Formula (2), Ar.sub.2, Ar.sub.3, and
Ar.sub.4 are individually a C.sub.6-50 arylene group or an organic
group containing a heterocyclic group, and T is a carbonyl group or
a sulfonyl group. Arylene groups or heterocyclic groups in the
organic groups of Ar.sub.1 to Ar.sub.4 can be used individually or
in combination of two or more of them. The arylene group and the
heterocyclic group are, for example, a divalent to tetravalent
group.
[0035] The C.sub.6-50 arylene group is a divalent organic group
corresponding to an aryl group and examples thereof include
divalent groups corresponding to a phenyl group, an o-methylphenyl
group, a m-methylphenyl group, a p-methylphenyl group, an
o-chlorophenyl group, a m-chlorophenyl group, a p-chlorophenyl
group, an o-fluorophenyl group, a p-fluorophenyl group, an
o-methoxyphenyl group, a p-methoxyphenyl group, a p-nitrophenyl
group, a p-cyanophenyl group, an .alpha.-naphthyl group, a
.beta.-naphthyl group, an o-biphenylyl group, a m-biphenylyl group,
a p-biphenylyl group, a 1-anthryl group, a 2-anthryl group, a
9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a
3-phenanthryl group, a 4-phenanthryl group, a 9-phenanthryl group,
a fluorene group, a fluorene derivative group, a pyrene group, and
a pentacene group.
[0036] Examples of the heterocyclic group include organic groups
corresponding to heterocyclic rings such as pyrrole, thiophene,
furan, imidazole, triazole, oxazole, thiazole, pyrazole, isoxazole,
isothiazole, pyridine, pyridazine, pyrimidine, pyrazine,
piperidine, piperazine, morpholine, pyran, and carbazole.
[0037] The organic group containing a C.sub.6-50 arylene group can
be used as the above arylene group alone or as a combination of the
above arylene group with a group containing a carbon-carbon triple
bond and/or a group containing a carbon-carbon double bond.
[0038] Examples of the organic group containing the above arylene
group include an organic group containing a fluorene structure or
an organic group containing a biphenylene structure.
[0039] The unit structure of the polymer used in the present
invention can be exemplified as follows.
##STR00001## ##STR00002##
[0040] The resist underlayer film forming composition of the
present invention may contain a crosslinking agent component.
Examples of the crosslinking agent include a melamine-based
crosslinking agent, a substituted urea-based crosslinking agent,
and a polymer thereof-based crosslinking agent. The crosslinking
agent is preferably a crosslinking agent having at least two
crosslinkage forming substituents and examples thereof include
compounds such as methoxymethylated glycoluril, butoxymethylated
glycoluril, methoxymethylated melamine, butoxymethylated melamine,
methoxymethylated benzoguanamine, butoxymethylated benzoguanamine,
methoxymethylated urea, butoxymethylated urea, methoxymethylated
thiourea, and methoxymethylated thiourea. A condensation product of
these compounds can also be used.
[0041] As the crosslinking agent, a crosslinking agent having high
heat resistance can be used. As the crosslinking agent having high
heat resistance, a compound containing, in the molecule thereof, a
crosslinkage forming substituent having an aromatic ring (such as a
benzene ring and a naphthalene ring) can be preferably used.
[0042] Examples of such a compound include a compound having a
partial structure of Formula (4) below, a polymer or an oligomer
having a repeating unit of Formula (5) below.
##STR00003##
[0043] In Formula (4), R.sub.7 and R.sub.8 are individually a
hydrogen atom, a C.sub.1-10 alkyl group, or a C.sub.6-20 aryl
group; and n7 is an integer of 1 to 4, n8 is an integer of 1 to
(5-n7) and n7+n8 is an integer of 2 to 5. In Formula (5), R.sub.9
is a hydrogen atom or a C.sub.1-10 alkyl group; R.sub.10 is a
C.sub.1-10 alkyl group; and n9 is an integer of 1 to 4, n10 is an
integer of 0 to (4-n9) and n9+n10 is an integer of 1 to 4. The
polymer and the oligomer can be used in a range of the number of
repeating unit structures of 2 to 100 or 2 to 50. Examples of the
alkyl group and the aryl group include individually the above
examples.
[0044] The compound of Formula (4), the polymer, oligomer thereof
and the compound of Formula (5), the polymer and oligomer thereof
are exemplified as follows.
##STR00004## ##STR00005## ##STR00006## ##STR00007##
[0045] The above compounds are commercially available as the
products of Asahi Organic Chemicals Industry Co., Ltd. and Honshu
Chemical Industry Co., Ltd. For example, among the above
crosslinking agents, a compound of Formula (6-21) is commercially
available from Asahi Organic Chemicals Industry Co., Ltd. under a
trade name: TM-BIP-A.
[0046] Although the additive amount of the crosslinking agent is
varied depending on the used coating solvent, the used ground
substrate, the required viscosity of solution, the required film
shape, and the like, it is 0.001 to 80% by mass, preferably 0.01 to
50% by mass, further preferably 0.05 to 40% by mass, based on the
total mass of the solid content. Although the crosslinking agent
may effect a crosslinking reaction by self-condensation, when a
crosslinkable substituent exists in the above polymer of the
present invention, the crosslinking agent can effect the
crosslinking reaction with such a crosslinkable substituent.
[0047] In the present invention, as a catalyst for accelerating the
crosslinking reaction, an acidic compound such as p-toluenesulfonic
acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonic
acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic
acid, hydroxybenzoic acid, and naphthalenecarboxylic acid or/and a
thermoacid generator such as 2,4,4,6-tetrabromocyclohexadienone,
benzoin tosylate, 2-nitrobenzyl tosylate, and organic sulfonic acid
alkyl esters can be blended. The blending amount thereof is 0.0001
to 20% by mass, preferably 0.0005 to 10% by mass, more preferably
0.01 to 3% by mass, based on the total mass of the solid
content.
[0048] In the coating-type underlayer film forming composition for
lithography of the present invention, for conforming the acidity of
the underlayer film forming composition to the acidity of the
photoresist applied as an upper layer of the underlayer film
thereon in a lithography process, a photoacid generator can be
blended. Preferred examples of the photoacid generator include:
onium salt photoacid generators such as
bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate and
triphenylsulfonium trifluoromethanesulfonate; halogen-containing
compound photoacid generators such as
phenyl-bis(trichloromethyl)-s-triazine; and sulfonic acid-based
photoacid generators such as benzoin tosylate and
N-hydroxysuccinimide trifluoromethanesulfonate. The content of the
photoacid generator is 0.2 to 10% by mass, preferably 0.4 to 5% by
mass, based on the total mass of the solid content.
[0049] In the resist underlayer film material for lithography of
the present invention, besides the above components, if necessary,
an additional light absorber, a rheology controlling agent, an
adhesion assistant, a surfactant, and the like can be added.
[0050] As the additional light absorber, there can be preferably
used, for example, commercially available light absorbers described
in "Technology and market of industrial dyestuff" (published by CMC
Publishing CO., Ltd.) or "Dye handbook" (published by the Society
of Synthetic Organic Chemistry, Japan) such as C. I. Disperse
Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66,
68, 79, 82, 88, 90, 93, 102, 114, and 124; C. I. Disperse Orange 1,
5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; C. I. Disperse Red 1, 5,
7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199,
and 210; C. I. Disperse Violet 43; C. I. Disperse Blue 96; C. I.
Fluorescent Brightening Agent 112, 135, and 163; C. I. Solvent
Orange 2 and 45; C. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49;
C. I. Pigment Green 10; and C. I. Pigment Brown 2. The light
absorber is blended usually in a content of 10% by mass or less,
preferably 5% by mass or less, based on the total mass of the solid
content of the resist underlayer film material for lithography.
[0051] The rheology controlling agent is added for the purpose of
mainly enhancing the fluidity of the resist underlayer film forming
composition, particularly enhancing the homogeneity of the film
thickness of the resist underlayer film or enhancing the filling
property of the resist underlayer film forming composition into the
inside of a hole, in a baking process. Specific examples of the
rheology controlling agent include: phthalic acid derivatives such
as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate,
dihexyl phthalate, and butylisodecyl phthalate; adipic acid
derivatives such as di-n-butyl adipate, diisobutyl adipate,
diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives
such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate;
oleic acid derivatives such as methyl oleate, butyl oleate, and
tetrahydrofurfuryl oleate; and stearic acid derivatives such as
n-butyl stearate and glyceryl stearate. These rheology controlling
agents are blended in a content of usually less than 30% by mass,
based on the total mass of the solid content of the resist
underlayer film material for lithography.
[0052] The adhesion assistant is added for the purpose of mainly
enhancing the adhesion of the resist underlayer film forming
composition and the substrate or the resist, particularly
preventing the resist from being peeled during development.
Specific examples of the adhesion assistant include: chlorosilanes
such as trimethylchlorosilane, dimethylvinylchlorosilane,
methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane;
alkoxysilanes such as trimethylmethoxysilane,
dimethyldiethoxysilane, methyldimethoxysilane,
dimethylvinylethoxysilane, diphenyldimethoxysilane, and
phenyltriethoxysilane; silazanes such as hexamethyldisilazane,
N,N'-bis(trimethlsilyl)urea, dimethyltrimethylsilylamine, and
trimethylsilylimidazol; silanes such as vinyltrichlorosilane,
.gamma.-chloropropyltrimethoxysilane,
.gamma.-aminopropyltriethoxysilane, and
.gamma.-glycidoxypropyltrimethoxysilane; heterocyclic compounds
such as benzotriazole, benzimidazole, indazole, imidazole,
2-mercaptobenzimidazole, 2-mercaptobenzothiazole,
2-mercaptobenzooxazole, urazole, thiouracil, mercaptoimidazole, and
mercaptopyrimidine; and urea or thiourea compounds such as
1,1-dimethylurea and1,3-dimethylurea. These adhesion assistants are
blended in a content of usually less than 5% by mass, preferably
less than 2% by mass, based on the total mass of the solid content
of the resist underlayer film material for lithography.
[0053] In the resist underlayer film material for lithography of
the present invention, for causing no pinhole and no striation and
further, enhancing the applicability relative to a surface
unevenness, a surfactant can be blended. Examples of the surfactant
include: nonionic surfactants, for example polyoxyethylene alkyl
ethers such as polyoxyethylene lauryl ether, polyoxyethylene
stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene
oleyl ether, polyoxyethylene alkylallyl ethers such as
polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol
ether, polyoxyethylene-polyoxypropylene block copolymers, sorbitan
fatty acid esters such as sorbitan monolaurate, sorbitan
monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan
trioleate, and sorbitan tristearate, polyoxyethylene sorbitan fatty
acid esters such as polyoxyethylene sorbitan monolaurate,
polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan
monostearate, polyoxyethylene sorbitan trioleate, and
polyoxyethylene sorbitan tristearate; fluorine-based surfactants,
for example, EFTOP EF301, EF303, and EF352 (trade names,
manufactured by Tohkem Products Co., Ltd.), MEGAFAC F171, F173, and
R-30 (trade names, manufactured by DIC Corporation), Fluorad FC430
and FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahi
Guard AG710 and Surfron S-382, SC101, SC102, SC103, SC104, SC105,
and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.); and
Organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical
Co., Ltd.). The blending amount of the surfactant is usually 2.0%
by mass or less, preferably 1.0% by mass or less, based on the
total mass of the solid content of the resist underlayer film
material for lithography of the present invention. These
surfactants may be used individually or in combination of two or
more of them.
[0054] In the present invention, examples of the solvent for
dissolving the polymer, the crosslinking agent component, the
crosslinking catalyst, and the like include ethylene glycol
monomethyl ether, ethylene glycol monoethyl ether, methylcellosolve
acetate, ethylcellosolve acetate, diethylene glycol monomethyl
ether, diethylene glycol monoethyl ether, propylene glycol,
propylene glycol monomethyl ether, propylene glycol monomethyl
ether acetate, propylene glycol monoethyl ether, propylene glycol
monoethyl ether acetate, propylene glycol propyl ether acetate,
toluene, xylene, methyl ethyl ketone, cyclopentanone,
cyclohexanone, ethyl 2-hydroxypropionate, ethyl
2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl
hydroxyacetate, methyl 2-hydroxy-3-methylbutanate, methyl
3-methoxypropionate, ethyl 3-methoxypropionate, ethyl
3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate,
ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, and
butyl lactate. These organic solvents may be used individually or
in combination of two or more of them.
[0055] Furthermore, to the solvent, a high boiling point-solvent
such as propylene glycol monobutyl ether and propylene glycol
monobutyl ether acetate can be mixed to be used. Among these
solvents, propylene glycol monomethyl ether, propylene glycol
monomethyl ether acetate, ethyl lactate, butyl lactate, and
cyclohexanone are preferred for enhancing the leveling
property.
[0056] As the resist used in the present invention, a photoresist,
an electron beam resist, and the like can be used.
[0057] As the photoresist applied and formed on the resist
underlayer film for lithography in the present invention, both of a
negative-type photoresist and a positive-type photoresist can be
used. Examples of the photoresist include: a positive-type
photoresist containing a novolac resin and
1,2-naphthoquinonediazide sulfonic acid ester; a chemical
amplification type photoresist containing a binder having a group
elevating alkali dissolving rate by being decomposed by an acid,
and a photoacid generator; a chemical amplification type
photoresist containing an alkali-soluble binder, a low molecule
compound elevating alkali dissolving rate of a photoresist by being
decomposed by an acid, and a photoacid generator; a chemical
amplification type photoresist containing a binder having a group
elevating alkali dissolving rate by being decomposed by an acid, a
low molecule compound elevating alkali dissolving rate of a
photoresist by being decomposed by an acid, and a photoacid
generator; and a photoresist having, in the skeleton thereof, an Si
atom. Specific examples thereof include trade name: APEX-E
manufactured by Rohm and Haas Company.
[0058] Examples of the electron beam resist applied and formed on
the resist underlayer film for lithography in the present invention
include: a composition containing a resin containing a Si--Si bond
in the backbone thereof and containing an aromatic ring at a
terminal thereof, and an acid generator generating an acid by being
irradiated with an electron beam; or a composition containing
poly(p-hydroxystyrene) in which a hydroxy group is substituted with
an organic group containing N-carboxyamine and an acid generator
generating an acid by being irradiated with an electron beam. In
the later electron beam resist composition, an acid generated from
the acid generator by electron beam irradiation is reacted with an
N-carboxyaminoxy group in a side chain of the polymer and the side
chain of the polymer is decomposed to a hydroxy group to exhibit
alkali solubility and to be dissolved in an alkaline developer, so
that a resist pattern is formed. Examples of the acid generator
generating an acid by the electron beam irradiation include: a
halogenated organic compound such as
1,1-bis[p-chlorophenyl]-2,2,2-trichloroethane,
1,1-bis[p-methoxyphenyl]-2,2,2-trichloroethane,
1,1-bis[p-chlorophenyl]-2,2-dichloroethane, and
2-chloro-6-(trichloromethyl)pyridine; an onium salt such as a
triphenylsulfonium salt and a diphenyliodonium salt; and a sulfonic
acid ester such as nitrobenzyl tosylate and dinitrobenzyl
tosylate.
[0059] Examples of the developer for the resist having the resist
underlayer film formed using the resist underlayer film material
for lithography of the present invention include aqueous solutions
of alkalis such as: inorganic alkalis such as sodium hydroxide,
potassium hydroxide, sodium carbonate, sodium silicate, sodium
metasilicate, and ammonia water; primary amines such as ethylamine
and n-propylamine; secondary amines such as diethylamine and
di-n-butylamine; tertiary amines such as triethylamine and
methyldiethylamine; alcoholamines such as dimethylethanolamine and
triethanolamine; quaternary ammonium salts such as
tetramethylammonium hydroxide, tetraethylammonium hydroxide, and
choline; and cyclic amines such as pyrrole and piperidine.
Furthermore, to the aqueous solution of the above alkalis, an
appropriate amount of alcohols such as isopropyl alcohol or a
nonion-based or the like surfactant may be added to be used. Among
them, a preferred developer is a quaternary ammonium salt and
further preferred developers are tetramethylammonium hydroxide and
choline.
[0060] Next, the forming method of the resist pattern of the
present invention is described. Onto a substrate (for example, a
transparent substrate such as a glass substrate and an ITO
substrate which are coated with silicon/silicon dioxide) used for
the production of a precise integrated circuit element, a resist
underlayer film forming composition is applied by an appropriate
coating method such as spinner and coater, and is baked to be cured
to produce a coating-type underlayer film. The resist underlayer
film has a film thickness of preferably 0.01 to 3.0 .mu.m. The
conditions for baking after coating are at 80 to 350.degree. C. and
for 0.5 to 120 minutes. Then, onto the resist underlayer film,
either directly or if necessary, through a film formed with one
layer or several layers of a coating material on the coating-type
underlayer film, the resist is applied and the resist is irradiated
with light or an electron beam through a predetermined mask. Then,
by developing, rinsing, and drying the resist, an advantageous
resist pattern can be obtained. If necessary, heating after
irradiation with light or an electron beam (PEB: Post Exposure
Bake) can be performed. Then, by removing the resist underlayer
film in a part at which the resist is removed by development in the
above process by dry etching, a desired pattern can be formed on
the substrate.
[0061] The exposure light for the photoresist is a chemical ray
such as a near ultraviolet ray, a far ultraviolet ray, or an
extreme ultraviolet ray (for example, EUV) and as the exposure
light, light of a wavelength of 248 nm (KrF laser light), 193 nm
(ArF laser light), or 157 nm (F.sub.2 laser light) is used. The
light irradiating method is not particularly limited to be used as
long as the method is a method capable of generating an acid from
the photoacid generator and the light irradiating method is
performed with an exposure dose of 1 to 2,000 mJ/cm.sup.2, 10 to
1,500 mJ/cm.sup.2, or 50 to 1,000 mJ/cm.sup.2.
[0062] The electron beam irradiation for the electron beam resist
can be performed, for example, using an electron beam irradiating
apparatus.
[0063] In the present invention, a semiconductor device can be
produced through a process of forming a resist underlayer film with
a resist underlayer film forming composition on a semiconductor
substrate, a process of forming a resist film on the resist
underlayer film, a process of forming a resist pattern by light
irradiation or electron beam irradiation and development, a process
of etching the resist underlayer film according to the resist
pattern, and a process of processing the semiconductor substrate
according to the patterned resist underlayer film.
[0064] Progress in refinement of the resist pattern will cause a
problem of the resolution or collapse of a resist pattern after
development; therefore, thinning of the resist will be required. In
this sense, it is difficult to secure a film thickness of the
resist pattern sufficient for processing the substrate, which
requires a process for imparting a function as a mask for
processing the substrate not only to the resist pattern, but also
to the resist underlayer film provided between the resist and the
semiconductor substrate to be processed. As a resist underlayer
film for such a process, there has started to be required a resist
underlayer film for lithography having a selection ratio of a dry
etching rate close to that of the resist, a resist underlayer film
for lithography having a selection ratio of a dry etching rate
smaller than that of the resist, and a resist underlayer film for
lithography having a selection ratio of a dry etching rate smaller
than that of the semiconductor substrate, as a resist underlayer
film, unlike a conventional resist underlayer film having high
etching rate property. In addition, to such a resist underlayer
film, reflection preventing ability can also be imparted, so that
such a resist underlayer film can provide a function of a
conventional anti-reflective coating in combination with other
advantageous properties.
[0065] For obtaining a fine resist pattern, there has started to be
used also a process of making the resist pattern and the resist
underlayer film thinner than the pattern width during development
of the resist, during dry etching of the resist underlayer film. As
a resist underlayer film for such a process, there has started to
be required a resist underlayer film having a selection ratio of a
dry etching rate close to that of the resist, unlike a conventional
high etching rate anti-reflective coating. To such a resist
underlayer film, a reflection preventing ability can be imparted,
so that such a resist underlayer film can provide a function of a
conventional anti-reflective coating in combination with other
advantageous properties.
[0066] In the present invention, the resist underlayer film of the
present invention is formed on a substrate, and then on the resist
underlayer film, either directly or if necessary, through a film
formed with one layer or several layers of coating material on the
resist underlayer film, the resist can be applied. This makes it
possible to process the substrate by selecting an appropriate
etching gas even when the pattern width of the resist is small and
the resist is coated in a small thickness for preventing a pattern
collapse.
[0067] That is, through: a process of forming the resist underlayer
film with a resist underlayer film forming composition on a
semiconductor substrate; a process of forming a hardmask with a
coating material containing a silicon component or the like on the
resist underlayer film; a process of forming a resist film further
on the hardmask; a process of forming a resist pattern by
irradiation with light or an electron beam and development; a
process of etching the hardmask according to the resist pattern; a
process of etching the resist underlayer film according to the
patterned hardmask; and a process of processing the semiconductor
substrate according to the patterned resist underlayer film, a
semiconductor device can be produced.
[0068] In the resist underlayer film forming composition for
lithography of the present invention, when the effect thereof as an
anti-reflective coating is considered, a light absorbing moiety is
incorporated into the skeleton, so that there is no substance
diffused into the photoresist during heating and drying of the
composition. Furthermore the light absorbing moiety has
satisfactorily high light absorbing performance; therefore, the
composition has high effect of preventing reflected light.
[0069] The resist underlayer film forming composition for
lithography of the present invention has high thermal stability,
can prevent contamination of an upper layer film of the resist
underlayer film by a decomposed substance during baking the resist
underlayer film, and can allow leeway in the temperature margin for
the baking process.
[0070] Furthermore, the resist underlayer film material for
lithography of the present invention can be used, depending on the
process condition, as a film having a function of preventing
reflection of light and further, a function of preventing an
interaction between the substrate and the photoresist or a function
of preventing an adverse action of a material used for the
photoresist or a substance generated during light exposure of the
photoresist against the substrate.
EXAMPLE
Synthesis Example 1
[0071] Into a flask equipped with a stirrer, a reflux apparatus,
and a thermometer, 28.04 g of 9,9-bis(4-hydroxyphenyl)fluorene,
13.97 g of 4,4'-difluorobenzophenone, 12.32 g of potassium
carbonate, and 162.56 g of N-methyl-2-pyrrolidinone were charged.
Then, the inside of the flask was purged with nitrogen and the
flask was heated until the inner temperature thereof became
140.degree. C., followed by effecting the reaction for about 24
hours. The synthesized polymer was cooled down to room temperature
and the reaction mixture was filtered for removing a precipitate to
recover the resultant reaction filtrate. The reaction filtrate was
mixed with about 10 mL of a mixture of N-methyl-2-pyrrolidinone and
2 mol/L hydrochloric acid in a volume ratio of 90:10. Then, the
resultant reaction filtrate was charged into methanol to perform
reprecipitation purification of the reaction filtrate.
[0072] Furthermore, the resultant precipitate was washed with water
and methanol and was vacuum-dried at 85.degree. C. for about one
day to obtain a polyether used in the present invention. The
obtained polymer corresponded to Formula (3-1). The obtained
polymer having an ether structure was subjected to GPC analysis and
the polymer had a weight average molecular weight of 6,900 and a
polydispersity Mw/Mn of 1.83 in terms of standard polystyrene.
Synthesis Example 2
[0073] Into a 100 mL three-neck flask, 6.76 g of
6,6'-(9H-fluorene-9,9-diyl)dinaphthalene-2-ole, 3.27 g of
4,4'-difluorobenzophenone, 42.72 g of N-methyl-2-pyrrolidinone, and
2.49 g of potassium carbonate were charged. Then, the inside of the
flask was purged with nitrogen and the flask was heated to
170.degree. C., followed by effecting the reaction for about 24
hours. Then, to the resultant reaction mixture, 0.65 g of
1-naphthol dissolved in 5.84 g of N-methyl-2-pyrrolidinone was
added and the resultant reaction mixture was stirred further for 2
hours. After the completion of the reaction, the reaction mixture
was diluted with 20 g of N-methyl-2-pyrrolidinone and a precipitate
was removed by filtration. The recovered filtrate was dropped into
a mixed solution of methanol/water/toluene (350 g/50 g/30 g) to
perform reprecipitation. The resultant precipitate was filtered
under reduced pressure and the filtered substance was dried under
reduced pressure at 85.degree. C. over one night. Then, 7.92 g of a
polyether was obtained as a light skin color powder. The obtained
polymer corresponded to Formula (3-2). By GPC, the obtained polymer
had a weight average molecular weight Mw of 9,400 and a
polydispersity Mw/Mn of 2.21 that were measured in terms of
polystyrene.
Synthesis Example 3
[0074] Into a 100 mL three-neck flask, 5.09 g of
4-(4-fluorophenylethynyl)phenol, 45.84 g of
N-methyl-2-pyrrolidinone, and 3.65 g of potassium carbonate were
charged. Then, the inside of the flask was purged with nitrogen and
the flask was heated to 170.degree. C., followed by effecting the
reaction for about 24 hours. After the completion of the reaction,
a precipitate was removed by filtration. The recovered filtrate was
dropped into 400 g of methanol to perform reprecipitation. The
resultant precipitate was filtered under reduced pressure and the
filtered substance was dried under reduced pressure at 85.degree.
C. over one night. Then, 5.12 g of a polyether was obtained as a
green color powder. The obtained polymer corresponded to Formula
(3-3). By GPC, the obtained polymer had a weight average molecular
weight Mw of 51,000 and a polydispersity Mw/Mn of 5.47 that were
measured in terms of polystyrene.
Synthesis Example 4
[0075] Into a 100 mL three-neck flask, 2.76 g of
p-(3,4-difluorophenylethynyl)phenol, 2.10 g of
9,9-bis(4-hydroxyphenyl)fluorene, 27.57 g of
N-methyl-2-pyrrolidinone, and 3.48 g of potassium carbonate were
charged. Then, the inside of the flask was purged with nitrogen and
the flask was heated to 150.degree. C., followed by effecting the
reaction for about 6 hours. After the completion of the reaction, a
precipitate was removed by filtration. The recovered filtrate was
dropped into a mixed solution of methanol/water (500 g/250 g) to
perform reprecipitation. The resultant precipitate was filtered
under reduced pressure and the filtered substance was dried under
reduced pressure at 85.degree. C. over one night. Then, 3.70 g of a
polyether was obtained as a skin color powder. The obtained polymer
corresponded to Formula (3-4). By GPC, the obtained polymer had a
weight average molecular weight Mw of 20,000 and a polydispersity
Mw/Mn of 4.49 that were measured in terms of polystyrene.
Synthesis Example 5
[0076] Into a 100 mL three-neck flask, 8.06 g of
9,9-bis(4-hydroxyphenyl)fluorene, 4.81 g of 2,4-difluorobiphenyl,
32.35 g of N-methyl-2-pyrrolidinone, and 6.99 g of potassium
carbonate were charged. Then, the inside of the flask was purged
with nitrogen and the flask was heated to 170.degree. C., followed
by effecting the reaction for about 24 hours. Then, to the
resultant reaction mixture, 0.99 g of 1-naphthol dissolved in 8.95
g of N-methyl-2-pyrrolidinone was added and the resultant reaction
mixture was stirred further for 2 hours. After the completion of
the reaction, a precipitate was removed by filtration. The
recovered filtrate was dropped into a mixed solution of
methanol/water (160 g/40 g) to perform reprecipitation. The
resultant precipitate was filtered under reduced pressure and the
filtered substance was dried under reduced pressure at 85.degree.
C. over one night. Then, 5.90 g of a polyether was obtained as a
skin color powder. The obtained polymer corresponded to Formula
(3-5). By GPC, the obtained polymer had a weight average molecular
weight Mw of 1,000 and a polydispersity Mw/Mn of 1.21 that were
measured in terms of polystyrene.
Synthesis Example 6
[0077] As one example of synthesis of a polymer having a polyether
structure, into a flask equipped with a stirrer, a reflux
apparatus, and a thermometer, 32.02 g of
2,2-bis(4-hydroxyphenyl)propane, 25.97 g of
4,4'-difluorobenzophenone, 21.30 g of potassium carbonate, and
237.76 g of N-methyl-2-pyrrolidinone were charged. Then, the inside
of the flask was purged with nitrogen and the flask was heated
until the inner temperature thereof became 140.degree. C., followed
by effecting the reaction for about 24 hours. The synthesized
polymer was cooled down to room temperature and the reaction
mixture was filtered for removing a precipitate to recover the
resultant reaction filtrate. The reaction filtrate was mixed with
about 10 mL of a mixture of N-methyl-2-pyrrolidinone and 2 mol/L
hydrochloric acid in a volume ratio of 90:10. Then, the resultant
reaction filtrate was charged into a mixed solution of
methanol/water (volume ratio=90/10) to perform reprecipitation
purification of the reaction filtrate.
[0078] Furthermore, the resultant precipitate was washed with water
and methanol and was vacuum-dried at 85.degree. C. for about one
day to obtain a polyether used in the present invention. The
obtained polymer corresponded to Formula (3-6). The obtained
polymer having an ether structure was subjected to GPC analysis and
the polymer had a weight average molecular weight of 7,600 and a
polydispersity Mw/Mn of 1.96 in terms of standard polystyrene.
Synthesis Example 7
[0079] As one example of synthesis of a polymer having a polyether
structure, into a flask equipped with a stirrer, a reflux
apparatus, and a thermometer, 17.52 g of
9,9-bis(4-hydroxyphenyl)fluorene, 6.22 g of
2,6-difluorobenzonitrile, 7.64 g of potassium carbonate, and 94.63
g of N-methyl-2-pyrrolidinone were charged. Then, the inside of the
flask was purged with nitrogen and the flask was heated until the
inner temperature thereof became 140.degree. C., followed by
effecting the reaction for about 24 hours. The synthesized polymer
was cooled down to room temperature and the reaction mixture was
filtered for removing a precipitate to recover the resultant
reaction filtrate. The reaction filtrate was mixed with about 10 mL
of a mixture of N-methyl-2-pyrrolidinone and 2 mol/L hydrochloric
acid in a volume ratio of 90:10. Then, the resultant reaction
filtrate was charged into a methanol solution to perform
reprecipitation purification of the reaction filtrate.
[0080] Furthermore, the resultant precipitate was washed with water
and methanol and was vacuum-dried at 85.degree. C. for about one
day to obtain 19.72 g of a polyether used in the present invention.
The obtained polymer corresponded to Formula (3-7). The obtained
polymer having an ether structure was subjected to GPC analysis and
the polymer had a weight average molecular weight of 15,000 and a
polydispersity Mw/Mn of 2.65 in terms of standard polystyrene.
Synthesis Example 8
[0081] As one example of synthesis of a polymer having a polyether
structure, into a flask equipped with a stirrer, a reflux
apparatus, and a thermometer, 26.29 g of
9,9-bis(4-hydroxyphenyl)fluorene, 11.35 g of
2,5-difluoronitrobenzene, 11.40 g of potassium carbonate, and
147.07 g of N-methyl-2-pyrrolidinone were charged. Then, the inside
of the flask was purged with nitrogen and the flask was heated
until the inner temperature thereof became 140.degree. C., followed
by effecting the reaction for about 24 hours. The synthesized
polymer was cooled down to room temperature and the reaction
mixture was filtered for removing a precipitate to recover the
resultant reaction filtrate. The reaction filtrate was mixed with
about 10 mL of a mixture of N-methyl-2-pyrrolidinone and 2 mol/L
hydrochloric acid in a volume ratio of 90:10. Then, the resultant
reaction filtrate was charged into a methanol solution to perform
reprecipitation purification of the reaction filtrate.
[0082] Furthermore, the resultant precipitate was washed with water
and methanol and was vacuum-dried at 85.degree. C. for about one
day to obtain 28.39 g of a polyether used in the present invention.
The obtained polymer corresponded to Formula (3-8). The obtained
polymer having an ether structure was subjected to GPC analysis and
the polymer had a weight average molecular weight of 4,400 and a
polydispersity Mw/Mn of 1.70 in terms of standard polystyrene.
Example 1
[0083] 3 g of the resin obtained in Synthesis Example 1 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 2
[0084] 3 g of the resin obtained in Synthesis Example 2 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 3
[0085] 3 g of the resin obtained in Synthesis Example 3 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 4
[0086] 3 g of the resin obtained in Synthesis Example 4 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 5
[0087] 3 g of the polymer obtained in Synthesis Example 5 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 6
[0088] 3 g of the polymer obtained in Synthesis Example 6 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 7
[0089] To 20 g of the resin obtained in Synthesis Example 1, 3.0 g
of a crosslinking agent (manufactured by Japan Cytec Industries,
Inc., containing as a component, tetramethoxymethyl glycoluril,
Formula (7-1)) and 0.30 g of p-toluenesulfonic acid as a catalyst
were mixed and the resultant mixture was dissolved in 88 g of
cyclohexanone to prepare a solution of a resist underlayer film
forming composition used for a lithography process by a multilayer
film.
##STR00008##
Example 8
[0090] To 20 g of the resin obtained in Synthesis Example 2, 3.0 g
of a crosslinking agent (manufactured by Japan Cytec Industries,
Inc., containing as a component, tetramethoxymethyl glycoluril,
Formula (7-1)), 0.30 g of pyridinium p-toluenesulfonate as a
catalyst, and 0.06 g of MEGAFAC R-30 as a surfactant were mixed and
the resultant mixture was dissolved in 88 g of cyclohexanone to
prepare a solution of a resist underlayer film forming composition
used for a lithography process by a multilayer film.
Comparative Example 1
[0091] A solution of a cresol novolac resin (commercial product,
weight average molecular weight: 4,000) was used.
Example 9
[0092] 3 g of the polymer obtained in Synthesis Example 7 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Example 10
[0093] 3 g of the polymer obtained in Synthesis Example 8 was
dissolved in 12 g of cyclohexanone to prepare a solution of a
resist underlayer film forming composition used for a lithography
process by a multilayer film.
Comparative Example 2
[0094] 3 g of polyethylene glycol (manufactured by Tokyo Chemical
Industry Co., Ltd.) having a molecular weight of 1,000 was
dissolved in 12 g of propylene glycol monoethyl ether acetate to
prepare a solution.
[0095] (Measurement of Optical Parameters)
[0096] The resist underlayer film solutions prepared in Examples 1
to 10 and Comparative Examples 1 and 2 were individually applied
onto a silicon wafer with a spin coater. The solution was baked on
a hot plate at 240.degree. C. for 1 minute (in Comparative Example
1: at 205.degree. C. for 1 minute, in Comparative Example 2: at
160.degree. C. for 1 minute) or at 400.degree. C. for 2 minutes to
form a resist underlayer film (film thickness: 0.05 .mu.m). The
refractive index (n value) at a wavelength of 193 nm and optical
absorptivity (k value, also called attenuation coefficient) of
these resist underlayer films were measured using a spectroscopic
ellipsometer. The results of the measurements are listed in Table
1.
TABLE-US-00001 TABLE 1 Refractive index n and optical absorptivity
k n k (193 nm) (193 nm) Example 1 Film baked at 240.degree. C. 1.48
0.77 Film baked at 400.degree. C. 1.48 0.75 Example 2 Film baked at
240.degree. C. 1.39 0.49 Film baked at 400.degree. C. 1.39 0.51
Example 3 Film baked at 240.degree. C. 1.55 0.59 Film baked at
400.degree. C. 1.54 0.63 Example 4 Film baked at 240.degree. C.
1.49 0.64 Film baked at 400.degree. C. 1.63 0.73 Example 5 Film
baked at 240.degree. C. 1.47 0.77 Film baked at 400.degree. C. 1.46
0.73 Example 6 Film baked at 240.degree. C. 1.58 0.81 Film baked at
400.degree. C. 1.57 0.79 Example 7 Film baked at 240.degree. C.
1.49 0.72 Film baked at 400.degree. C. 1.47 0.73 Example 8 Film
baked at 240.degree. C. 1.43 0.49 Film baked at 400.degree. C. 1.40
0.51 Example 9 Film baked at 240.degree. C. 1.43 0.71 Film baked at
400.degree. C. 1.41 0.70 Example 10 Film baked at 240.degree. C.
1.47 0.75 Film baked at 400.degree. C. 1.46 0.74 Comparative Film
baked at 205.degree. C. 1.53 0.42 Example 1 Film baked at
400.degree. C. Unmeasurable Unmeasurable Comparative Film baked at
160.degree. C. 1.68 0.00 Example 2 Film baked at 400.degree. C.
Unmeasurable Unmeasurable
[0097] (Dissolution Test into Photoresist Solvents)
[0098] The solutions of the resist underlayer film forming
composition prepared in Examples 1 to 10 were individually applied
onto a silicon wafer with a spin coater. The solution was baked on
a hot plate at 240.degree. C. for 1 minute (in Comparative Example
1: at 205.degree. C. for 1 minute, in Comparative Example 2: at
160.degree. C. for 1 minute) or at 400.degree. C. for 2 minutes to
form a resist underlayer film (film thickness: 0.20 .mu.m). The
resist underlayer film was subjected to an immersion test in a
solvent used for the resist such as ethyl lactate, propylene glycol
monomethyl ether, propylene glycol monomethyl ether acetate, and
cyclohexanone.
[0099] Although the films prepared by baking the solutions of
Examples 1 to 6 and Examples 9 and 10 at 240.degree. C. for 1
minute were dissolved in these solvents, it was confirmed that the
films prepared by baking the solutions of these Examples at
400.degree. C. for 2 minutes were insoluble in these solvents. In
addition, it was also confirmed that not only the films prepared by
baking the solutions of Examples 7 and 8 at 400.degree. C. for 2
minutes, but also the films prepared by baking the solutions of
Examples 7 and 8 at 240.degree. C. for 1 minute were insoluble in
these solvents.
[0100] (Measurement of Dry Etching Rates)
[0101] The etcher and the etching gas used for the measurement of
dry etching rates were as follows. [0102] RIE-10NR (manufactured by
Samco, Inc.): CF.sub.4
[0103] The solutions of the resist underlayer film forming
composition prepared in Examples 1 to 10 and Comparative Examples 1
and 2 were individually applied onto a silicon wafer with a spin
coater. The solution was baked on a hot plate at 240.degree. C. for
1 minute (in Comparative Example 1: at 205.degree. C. for 1 minute,
in Comparative Example 2: at 160.degree. C. for 1 minute) or at
400.degree. C. for 2 minutes to form a resist underlayer film (film
thickness: 0.20 .mu.m). Using CF.sub.4 gas as an etching gas, dry
etching rates of the resist underlayer films were measured.
[0104] In the same manner, a phenol novolac resin solution was
applied onto a silicon wafer with a spin coater to form a coating
film. Using CF.sub.4 gas as an etching gas, the dry etching rate of
the coating film was measured and was compared with the dry etching
rate of the resist underlayer films of Examples 1 to 10 and
Comparative Examples 1 and 2. The results thereof are listed in
Table 2. In Examples 1 to 10, the dry etching rate ratio is a dry
etching rate ratio (1) of (resist underlayer film baked at
240.degree. C.)/(phenol novolac resin baked at 240.degree. C.) and
a dry etching rate ratio (2) of (resist underlayer film baked at
400.degree. C.)/(phenol novolac resin baked at 240.degree. C.).
[0105] In Comparative Example 1, the dry etching rate ratio is a
dry etching rate ratio (1) of (resist underlayer film baked at
205.degree. C.)/(phenol novolac resin baked at 240.degree. C.) and
a dry etching rate ratio (2) of (resist underlayer film baked at
400.degree. C.)/(phenol novolac resin baked at 240.degree. C.).
[0106] In Comparative Example 2, the dry etching rate ratio is a
dry etching rate ratio (1) of (resist underlayer film baked at
160.degree. C.)/(phenol novolac resin baked at 240.degree. C.) and
a dry etching rate ratio (2) of (resist underlayer film baked at
400.degree. C.)/(phenol novolac resin baked at 240.degree. C.).
TABLE-US-00002 TABLE 2 Dry etching rate ratios Example 1 Dry
etching rate ratio (1) 0.84 Dry etching rate ratio (2) 0.84 Example
2 Dry etching rate ratio (1) 0.79 Dry etching rate ratio (2) 0.79
Example 3 Dry etching rate ratio (1) 0.95 Dry etching rate ratio
(2) 0.95 Example 4 Dry etching rate ratio (1) 0.91 Dry etching rate
ratio (2) 0.98 Example 5 Dry etching rate ratio (1) 0.86 Dry
etching rate ratio (2) 0.85 Example 6 Dry etching rate ratio (1)
0.96 Dry etching rate ratio (2) 0.96 Example 7 Dry etching rate
ratio (1) 0.86 Dry etching rate ratio (2) 0.85 Example 8 Dry
etching rate ratio (1) 0.82 Dry etching rate ratio (2) 0.80 Example
9 Dry etching rate ratio (1) 0.82 Dry etching rate ratio (2) 0.81
Example 10 Dry etching rate ratio (1) 0.85 Dry etching rate ratio
(2) 0.84 Comparative Dry etching rate ratio (1) 1.00 Example 1 Dry
etching rate ratio (2) Unmeasurable Comparative Dry etching rate
ratio (1) 2.18 Example 2 Dry etching rate ratio (2)
Unmeasurable
[0107] (Heat Resistance Test of Films)
[0108] The solutions of the resist underlayer film forming
composition prepared in Examples 1 to 10 and Comparative Examples 1
and 2 were individually applied onto a silicon wafer with a spin
coater. The solution was baked on a hot plate at 400.degree. C. for
2 minutes to form a resist underlayer film (film thickness: 0.20
.mu.m). The obtained film was heated with a rate of 10.degree.
C./min and was subjected to thermogravimetric analysis in the
atmosphere to measure a temperature at which the mass of the film
decreased by 5%. The results thereof are listed in Table 3.
TABLE-US-00003 TABLE 3 Temperature at which mass of the film
decreased by 5% Film baked at 400.degree. C. for 2 minutes Example
1 496.degree. C. Example 2 500.degree. C. Example 3 452.degree. C.
Example 4 369.degree. C. Example 5 395.degree. C. Example 6
481.degree. C. Example 7 482.degree. C. Example 8 472.degree. C.
Example 9 500.degree. C. or more Example 10 408.degree. C.
Comparative Unmeasurable (when baked at 400.degree. C., the Example
1 film was sublimated) Comparative Unmeasurable (when baked at
400.degree. C., the Example 2 film was sublimated)
INDUSTRIAL APPLICABILITY
[0109] The resist underlayer film material of the present invention
used for a lithography process by a multilayer film can provide a
resist underlayer film having a selection ratio of a dry etching
rate close to or smaller than that of a photoresist and a selection
ratio of a dry etching rate smaller than that of a semiconductor
substrate and further, can provide an effect as an anti-reflective
coating in combination with other advantageous properties unlike a
conventional anti-reflective coating having high etching rate
property. In addition, it became apparent that the underlayer film
material of the present invention has such heat resistance that
allows a hardmask to be formed on the underlayer film as an upper
layer of the underlayer film by vapor deposition.
* * * * *