U.S. patent application number 09/397117 was filed with the patent office on 2002-02-07 for bottom anti-reflective coating material composition for photoresist and method of forming resist pattern using the same.
Invention is credited to MIZUTANI, KAZUYOSHI, MOMOTA, MAKOTO.
Application Number | 20020015909 09/397117 |
Document ID | / |
Family ID | 17480729 |
Filed Date | 2002-02-07 |
United States Patent
Application |
20020015909 |
Kind Code |
A1 |
MIZUTANI, KAZUYOSHI ; et
al. |
February 7, 2002 |
BOTTOM ANTI-REFLECTIVE COATING MATERIAL COMPOSITION FOR PHOTORESIST
AND METHOD OF FORMING RESIST PATTERN USING THE SAME
Abstract
A bottom anti-reflective coating material composition for a
photoresist comprising the following components (a) to (d): (a) a
polymer containing a dye structure having a molar extinction
coefficient of 1.0.times.10.sup.4 or more to light including a
wavelength used for exposure of the photoresist; (b) a thermal
crosslinking agent which is activated by an acid to react with
component (a) described above, thereby forming a crosslinked
structure; (c) a sulfonic acid ester compound or diaryl iodonium
salt, which is decomposed to generate an acid with heating at
temperature between 150 to 200.degree. C.; and (d) an organic
solvent capable of dissolving components (a) to (c) described
above. The bottom anti-reflective coating material composition for
a photoresist provides a bottom anti-reflective coating having a
large absorbance to light including a wavelength used for exposure,
and an adverse effect due to a standing wave generated by
reflection from a substrate can be reduced, a limiting resolution
of the photoresist is increased, and a good resist profile is
obtained. A method of forming a resist pattern using the
composition is also disclosed.
Inventors: |
MIZUTANI, KAZUYOSHI;
(SHIZUOKA, JP) ; MOMOTA, MAKOTO; (SHIZUOKA,
JP) |
Correspondence
Address: |
SUGHRUE MION ZINN MACPEAK & SEAS PLLC
2100 PENNSYLVANIA AVENUE N W
WASHINGTON
DC
20037
|
Family ID: |
17480729 |
Appl. No.: |
09/397117 |
Filed: |
September 16, 1999 |
Current U.S.
Class: |
430/270.1 ;
430/281.1; 430/286.1; 430/338 |
Current CPC
Class: |
G03F 7/091 20130101 |
Class at
Publication: |
430/270.1 ;
430/281.1; 430/286.1; 430/338 |
International
Class: |
G03F 007/09; G03F
007/004 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 24, 1998 |
JP |
10-270042 |
Claims
What is claimed is:
1. A bottom anti-reflective coating material composition for a
photoresist comprising the following components (a) to (d): (a) a
polymer containing a dye structure having a molar extinction
coefficient of 1.0.times.10.sup.4 or more to light including a
wavelength used for exposure of the photoresist; (b) a thermal
crosslinking agent which is activated by an acid to react with
component (a) described above, thereby forming a crosslinked
structure; (c) a sulfonic acid ester compound or diaryl iodonium
salt, which is decomposed to generate an acid with heating at
temperature between 150 to 200.degree. C.; and (d) an organic
solvent capable of dissolving components (a) to (c) described
above.
2. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1, wherein the polymer of component
(a) has a glass transition temperature of from 80 to 180.degree.
C.
3. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1, wherein the polymer of component
(a) contains a repeating unit having the dye structure in an amount
of 10% by weight or more.
4. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1, wherein the dye structure in the
polymer of component (a) is a structure represented by the
following formula (I) or (II); 12wherein W represents a linking
group to the polymer main chain; Y represents an oxygen atom, a
sulfur atom or .dbd.N--V; Z.sub.1 and Z.sub.2, which may be the
same or different, each represents an electron donating group; m
and n represent an integer of from 0 to 2 and from 0 to 3,
respectively, and when m and n each is 2 or 3, the Z.sub.1 groups
or Z.sub.2 groups may be the same or different; and V represents a
hydroxy group, an amino group, a straight chain, branched or cyclic
alkyl group having from 1 to 20 carbon atoms which may have a
substituent, an aromatic or heteroaromatic ring group having from 5
to 14 carbon atoms which may have a substituent or an alkoxy group
having from 1 to 20 carbon atoms.
5. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1, wherein the polymer of component
(a) is a polymer containing a repeating unit represented by the
following formula (IA) or (IIA): 13wherein R.sup.1 represents a
hydrogen atom, a methyl group, a chlorine atom, a bromine atom or a
cyano group; X represents a divalent linking group; Y represents an
oxygen atom, a sulfur atom or --N--V; Z.sub.1 and Z.sub.2, which
may be the same or different, each represents an electron donating
group; m and n represent an integer of from 0 to 2 and from 0 to 3,
respectively, and when m and n each is 2 or 3, the Z.sub.1 groups
or Z.sub.2 groups may be the same or different; and V represents a
hydroxy group, an amino group, a straight chain, branched or cyclic
alkyl group having from 1 to 20 carbon atoms which may have a
substituent, an aromatic or heteroaromatic ring group having from 5
to 14 carbon atoms which may have a substituent or an alkoxy group
having from 1 to 20 carbon atoms.
6. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 5, wherein Z.sub.1 and Z.sub.2 in
formula (IA) or (IIA), which may be the same or different, each
represents a hydroxy group, --OR.sub.4 (wherein R.sub.4 represents
a hydrocarbon group having from 1 to 20 carbon atoms), --SR.sub.4
or --NR.sub.5R.sub.6 (wherein R.sub.5 and R.sub.6, which may be the
same or different, each represents a hydrogen atom or a hydrocarbon
group having from 1 to 20 carbon atoms).
7. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1, wherein the thermal crosslinking
agent of component (b) is a melamine, benzoguanamine, glycoluril or
urea compound substituted with at least one substituent selected
from a methylol group, an alkoxymethyl group and an acyloxymethyl
group.
8. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 7, wherein the thermal crosslinking
agent of component (b) is a compound selected from
hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine and
tetramethoxymethylglycoluril.
9. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1, wherein the compound of
component (c) is a salt of a diaryliodonium cation and an organic
sulfonic acid anion, or an organic sulfonic acid ester having from
3 to 20 carbon atoms.
10. A bottom anti-reflective coating material composition for a
photoresist comprising the following components (a'), (b) and (d):
(a') a polymer containing a repeating unit including a dye
structure having a molar extinction coefficient of
1.0.times.10.sup.4 or more to light including a wavelength used for
exposure of the photoresist and a repeating unit including a
sulfonic acid ester structure or diaryl iodonium structure, which
is decomposed to generate an acid with heating at temperature
between 150 to 200.degree. C.; (b) a thermal crosslinking agent
which is activated by an acid to react with component (a')
described above, thereby forming a crosslinked structure; and (c)
an organic solvent capable of dissolving components (a') and (b)
described above.
11. A method of forming a resist pattern comprising employing the
bottom anti-reflective coating material composition for a
photoresist as claimed in claim 1.
12. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 4, wherein Y in formula (I) is an
oxygen atom.
13. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 5, wherein the polymer of component
(a) further contains a repeating unit of a non-light-absorbing
monomer.
14. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 13, wherein the non-light-absorbing
monomer is selected from an acrylic ester, a methacrylic ester, an
acrylamide, a methacrylamide, an allyl compound, a vinyl ether, a
vinyl ester, a styrene and a crotonic ester.
15. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 13, wherein the non-light-absorbing
monomer is a monomer having a hydroxy group.
16. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 13, wherein the non-light-absorbing
monomer is an alkyl (meth)acrylate monomer containing the alkyl
group having from 1 to 10 carbon atoms.
17. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 5, wherein the polymer of component
(a) further contains a repeating unit having a crosslinking
group.
18. A bottom anti-reflective coating material composition for a
photoresist as claimed in claim 17, wherein the repeating unit
having a crosslinking group is represented by the following formula
(A), (B) or (C): 14wherein R.sup.2 represents a hydrogen atom, a
methyl group, a chlorine atom, a bromine atom or a cyano group; A
represents a functional group having a --CH.sub.2OH,
--CH.sub.2OR.sup.14 or --CH.sub.2OCOCH.sub.3 terminal group
(wherein R.sup.14 represents a hydrocarbon group having from 1 to
20 carbon atoms); B represents a functional group having a
--CO.sub.2H terminal group; and D represents a functional group
having an epoxy terminal group.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a composition of a bottom
anti-reflective coating material for a photoresist capable of
forming a bottom anti-reflective coating which is effective in
reducing an adverse effect of reflection from a background
substrate in a lithography process using various radiations, and to
a method of forming a resist pattern using the composition of a
bottom anti-reflective coating material.
BACKGROUND OF THE INVENTION
[0002] A photoresist is coated on a substrate such as semiconductor
wafer, glass, ceramic or metal to have a thickness of from 0.5 to 2
.mu.m by a spin coating method or a roller coating method and
thereafter subjected to heating, drying, printing of a circuit
pattern through an exposure mask with radiation such as ultraviolet
ray, post exposure baking if desired, and development to form an
image.
[0003] Etching is conducted using the image as a mask so as to
effect pattern working on a substrate. Representative examples of
the application field thereof include production process of
semiconductors such as IC, production of circuit substrates such as
liquid crystal and thermal head and other photofabrication
process.
[0004] In the semiconductor fine working using a photoresist,
accompanying the tendency towards finer dimensions, a matter of
great importance is the prevention of light reflection from the
substrate. For this purpose, a photoresist containing a light
absorbent has been conventionally used. However, the use has a
problem in that the resolution is impaired. Accordingly, a method
of providing a bottom anti-reflective coating (BARC) between the
photoresist and the substrate has been extensively investigated.
Known examples of the bottom anti-reflective coating include an
inorganic coating type such as titanium, titanium dioxide, titanium
nitride, chromium oxide, carbon and .alpha.-silicon, and an organic
coating type comprising a light absorbent and a polymer
material.
[0005] The former requires equipments such as a vacuum evaporation
apparatus, a CVD apparatus and a sputtering apparatus, for the
coating formation. The latter is advantageous since it does not
require any particular equipment, and a large number of
investigations have been made thereon.
[0006] For example, JP-B-7-69611 (the term "JP-B" as used herein
means an "examined Japanese patent publication") describes a
coating comprising a condensate of a diphenylamine derivative with
a formaldehyde-modified melamine resin, an alkali-soluble resin and
a light absorbent, U.S. Pat. No. 5,294,680 describes a reaction
product of a maleic anhydride copolymer with a diamine-type light
absorbent, JP-A-6-118631 (the term "JP-A" as used herein means an
"unexamined published Japanese patent application") describes a
coating comprising a resin binder and a methylolmelamine-base heat
cross-linking agent, JP-A-6-118656 describes an acrylic resin-type
anti-reflective coating containing within the same molecule a
carboxylic acid group, an epoxy group and a light absorbing group,
JP-A-8-87115 describes a coating comprising methylolmelamine and a
benzophenone-base light absorbent, and JP-A-8-179509 describes a
coating obtained by adding a low molecular light absorbent to a
polyvinyl alcohol resin.
[0007] The material for organic bottom anti-reflective coating
preferably has physical properties such that it exhibits a large
absorbance to radiations, it is insoluble in a photoresist solvent
(not to cause intermixing with a photoresist layer), it is free
from diffusion of a low molecular substance from the
anti-reflective coating material to the overcoat photoresist layer
during the coating or drying with heating, and it has a high dry
etching rate as compared with the photoresist. These are also
described, for example, in Proc. SPIE, Vol. 2195, 225-229
(1994).
[0008] Recently, from a standpoint of the rationalization of
production process, it has been desired to use a common solvent for
coating the bottom anti-reflective coating composition and the
resist composition. Thus, an attempt of adding to the bottom
anti-reflective coating composition a compound which causes a
crosslinking reaction by heating and hardens the coating to prevent
the occurrence of intermixing with the resist layer has been made
as described, for example, in JP-A-6-118631 and U.S. Pat. No.
5,693,691.
[0009] However, the compounds described in the above-described
patents fail to satisfy all these requirements and improvements
have been demanded. For example, some conventional bottom
anti-reflective coatings are insufficient in the light absorbing
power of the binder and require separate loading of a light
absorbent, and some contain a large amount of an aromatic light
absorbent for increasing the absorbance have a problem of the
occurrence of intermixing with the resist layer through interface
of the light absorbent. Further, those having, in the crosslinking
system, a functional group capable of increasing alkali
permeability such as a carboxylic acid group, are accompanied by a
problem in that when development with an alkaline aqueous solution
is performed, the anti-reflective coating swells to incur
deterioration of a resist pattern shape.
SUMMARY OF THE INVENTION
[0010] Therefore, an object of the present invention is to provide
a bottom anti-reflective coating material composition for a
photoresist, which is capable of forming a bottom anti-reflective
coating having a large absorbance to light including a wavelength
used for exposure, which does not cause intermixing with a
photoresist, and which can reduce an adverse effect due to a
standing wave generated by reflection from a substrate.
[0011] Another object of the present invention is to provide a
bottom anti-reflective coating material composition for a
photoresist, which is capable of forming a bottom anti-reflective
coating that can increase a limiting resolution of the photoresist
and provide a good resist profile.
[0012] A further object of the present invention is to provide a
method of forming a resist pattern, which is capable of forming an
excellent resist pattern.
[0013] Other objects of the present invention will become apparent
from the following description.
[0014] These objects of the present invention are accomplished with
the bottom anti-reflective coating material composition for a
photoresist and method of forming a resist pattern described
below.
[0015] (1) a bottom anti-reflective coating material composition
for a photoresist comprising the following components (a) to
(d):
[0016] (a) a polymer containing a dye structure having a molar
extinction coefficient of 1.0.times.10.sup.4 or more to light
including a wavelength used for exposure of the photoresist;
[0017] (b) a thermal crosslinking agent which is activated by an
acid to react with component (a) described above, thereby forming a
crosslinked structure;
[0018] (c) a sulfonic acid ester compound or diaryl iodonium salt,
which is decomposed to generate an acid with heating at temperature
between 150 to 200.degree. C.; and
[0019] (d) an organic solvent capable of dissolving components (a)
to (c) described above;
[0020] (2) a bottom anti-reflective coating material composition
for a photoresist as described in item (1) above, wherein the
polymer of component (a) has a glass transition temperature of from
80 to 180.degree. C.;
[0021] (3) a bottom anti-reflective coating material composition
for a photoresist as described in item (1) or (2) above, wherein
the polymer of component (a) contains a repeating unit having the
dye structure in an amount of 10% by weight or more;
[0022] (4) a bottom anti-reflective coating material composition
for a photoresist as described in any one of items (1) to (3)
above, wherein the dye structure in the polymer of component (a) is
a structure represented by the following formula (I) or (II); 1
[0023] wherein W represents a linking group to the polymer main
chain; Y represents an oxygen atom, a sulfur atom or .dbd.N--V;
Z.sub.1 and Z.sub.2, which may be the same or different, each
represents an electron donating group; m and n represent an integer
of from 0 to 2 and from 0 to 3, respectively, and when m and n each
is 2 or 3, the Z.sub.1 groups or Z.sub.2 groups may be the same or
different; and V represents a hydroxy group, an amino group, a
straight chain, branched or cyclic alkyl group having from 1 to 20
carbon atoms which may have a substituent, an aromatic or
heteroaromatic ring group having from 5 to 14 carbon atoms which
may have a substituent or an alkoxy group having from 1 to 20
carbon atoms;
[0024] (5) a bottom anti-reflective coating material composition
for a photoresist as described in item (4) above, wherein the
polymer of component (a) is a polymer containing a repeating unit
represented by the following formula (IA) or (IIA): 2
[0025] wherein R.sup.1 represents a hydrogen atom, a methyl group,
a chlorine atom, a bromine atom or a cyano group; X represents a
divalent linking group; and Y, Z.sub.1, Z.sub.2, m and n have the
same meanings as defined in formulae (I) and (II),
respectively;
[0026] (6) a bottom anti-reflective coating material composition
for a photoresist as described in item (5) above, wherein Z.sub.1
and Z.sub.2 in formula (IA) or (IIA), which may be the same or
different, each represents a hydroxy group, --OR.sub.4 (wherein
R.sub.4 represents a hydrocarbon group having from 1 to 20 carbon
atoms), --SR.sub.4 or --NR.sub.5R.sub.6 (wherein R.sub.5 and
R.sub.6, which may be the same or different, each represents a
hydrogen atom or a hydrocarbon group having from 1 to 20 carbon
atoms);
[0027] (7) a bottom anti-reflective coating material composition
for a photoresist as described in any one of items (1) to (6)
above, wherein the thermal crosslinking agent of component (b) is a
melamine, benzoguanamine, glycoluril or urea compound substituted
with at least one substituent selected from a methylol group, an
alkoxymethyl group and an acyloxymethyl group;
[0028] (8) a bottom anti-reflective coating material composition
for a photoresist as described in item (7), wherein the thermal
crosslinking agent of component (b) is a compound selected from
hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine and
tetramethoxymethyl-glycoluril;
[0029] (9) a bottom anti-reflective coating material composition
for a photoresist as described in any one of items (1) to (8),
wherein the compound of component (c) is a salt of a diaryliodonium
cation and an organic sulfonic acid anion, or an organic sulfonic
acid ester having from 3 to 20 carbon atoms;
[0030] (10) a bottom anti-reflective coating material composition
for a photoresist comprising the following components (a'), (b) and
(d):
[0031] (a') a polymer containing a repeating unit including a dye
structure having a molar extinction coefficient of
1.0.times.10.sup.4 or more to light including a wavelength used for
exposure of the photoresist and a repeating unit including a
sulfonic acid ester structure or diaryl iodonium structure, which
is decomposed to generate an acid with heating at temperature
between 150 to 200.degree. C.;
[0032] (b) a thermal crosslinking agent which is activated by an
acid to react with component (a') described above, thereby forming
a crosslinked structure; and
[0033] (c) an organic solvent capable of dissolving components (a')
and (b) described above; and
[0034] (11) a method of forming a resist pattern comprising
employing the bottom anti-reflective coating material composition
for a photoresist as described in any one of items (1) to (10).
DETAILED DESCRIPTION OF THE INVENTION
[0035] The bottom anti-reflective coating material composition for
a photoresist according to the present invention will be described
in detail below.
[0036] Component (a) in the composition is a polymer (hereinafter
also referred to as polymer (a) sometimes) containing a dye
structure necessary for exhibiting the anti-reflective function.
The dye structure has a molar extinction coefficient as large as
1.0.times.10.sup.4 or more, preferably 4.0.times.10.sup.4 or more
to light including a wavelength used for exposure of the
photoresist. For instance, in case of using a KrF excimer laser
(wavelength of 248 nm) as an exposure light source, the dye
structure satisfying the above described condition as to the molar
extinction coefficient includes an anthracene structure, a
phenanthrene structure, a benzophenone (which may have a hydroxy
group as a substituent) structure, a naphthalene-carbonyl
structure, and the like.
[0037] Among these structures, the structure represented by the
above described formula (I) or (II) is preferred, since it is
excellent in a dry etching property as well as it fulfills the
above described condition as to the molar extinction coefficient to
light used for exposure, e. g., a KrF excimer laser (wavelength of
248 nm) or a ArF excimer laser (wavelength of 193 nm).
[0038] In formula (I) or (II), W represents a linking group to the
polymer main chain. More specifically, the linking group preferably
includes a single bond, --CO.sub.2--, --NH--, --CONH--, --O--,
--CO--, --SO.sub.2--, a straight chain alkylene group having from 1
to 20 carbon atoms which may have a substituent, a branched
alkylene group having from 1 to 20 carbon atoms which may have a
substituent and an alkylene group having from 1 to 20 carbon atoms
which may have a cyclic alkylene structure. Also, linking groups
composed of a combination of two or more of these linking groups
are preferably used as W.
[0039] Suitable examples of the straight chain alkylene group
having from 1 to 20 carbon atoms include a methylene group, an
ethylene group, a propylene group, a butylene group, a pentylene
group and a hexylene group.
[0040] Suitable examples of the alkylene group having from 1 to 20
carbon atoms which may have a cyclic alkylene structure include a
cyclohexylene group, a cyclopentylene group and a cyclobutylene
group.
[0041] Suitable examples of the substituent for the above described
alkylene group include an alkyl group having from 1 to 10 carbon
atoms, --OH, --OR.sub.4 (wherein R.sub.4 represents an alkyl group
having from 1 to 20 carbon atoms), --SR.sub.4, --NR.sub.5R.sub.6
(wherein R.sub.5 and R.sub.6, which may be the same or different,
each represents a hydrogen atom or an alkyl group having from 1 to
20 carbon atoms) and a halogen atom.
[0042] Preferred examples of W include --O--,
--CO.sub.2C.sub.2H.sub.4O--, --CONHC.sub.2H.sub.4O--,
--CO.sub.2C.sub.2H.sub.4NH--, --CONHC.sub.2H.sub.4NH--,
--CO.sub.2CH.sub.2CH(OH)CH.sub.2O-- and
--CONHCH.sub.2CH(OH)CH.sub.2O--.
[0043] In formula (I), Y represents an oxygen atom, a sulfur atom
or .dbd.N--V wherein V represents a hydroxy group, an amino group,
a straight chain, branched or cyclic alkyl group having from 1 to
20 carbon atoms which may have a substituent, an aromatic or
heteroaromatic ring group having from 5 to 14 carbon atoms which
may have a substituent or an alkoxy group having from 1 to 20
carbon atoms.
[0044] Suitable examples of the straight chain, branched or cyclic
alkyl group having from 1 to 20 carbon atoms which may have a
substituent include a methyl group, an ethyl group, an n-propyl
group, an isopropyl group, an n-butyl group, an isobutyl group, a
tert-butyl group, an n-pentyl group, an n-hexyl group, a cyclohexyl
group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an
n-decyl group, an n-lauryl group, an n-stearyl group, a
2-hydroxyethyl group, a 2,3-dichloropropyl group and a
2,3-dibromopropul group.
[0045] Suitable examples of the aromatic or heteroaromatic ring
group having from 5 to 14 carbon atoms which may have a substituent
include a phenyl group, a naphthyl group, an anthryl group and a
phenanthryl group.
[0046] Suitable examples of the alkoxy group having from 1 to 20
carbon atoms include a methoxy group, an ethoxy group, an n-propoxy
group, an isopropoxy group, an n-butoxy group, a tert-butoxy group,
a phenoxy group and a benzyloxy group.
[0047] Preferred examples of Y include an oxygen atom, a sulfur
atom and --N(OH)--. An oxygen atom is particularly preferred.
[0048] In formula (I) or (II), Z.sub.1 and Z.sub.2, which may be
the same or different, each represents an electron donating group.
The electron donating group is preferably a group having a
Hammett's substituent constant .sigma..sub.P of a negative value.
In formula (I) or (II), m and n represent an integer of from 0 to 2
and from 0 to 3, respectively, and when m and n each is 2 or 3, the
Z.sub.1 groups or Z.sub.2 groups may be the same or different.
[0049] The electron donating group for Z.sub.1 and Z.sub.2
preferably includes --OH, --OR.sub.4 (wherein R.sub.4 represents an
alkyl group having from 1 to 20 carbon atoms) or --NR.sub.5R.sub.6
(wherein R.sub.5 and R.sub.6, which may be the same or different,
each represents a hydrogen atom or an alkyl group having from 1 to
20 carbon atoms). These groups each has the Hammett's substituent
constant .sigma..sub.p in a range of from -0.9 to -0.2.
[0050] Preferred examples of the alkyl group having from 1 to 20
carbon atoms for R.sub.4, R.sub.5 and R.sub.6 include a methyl
group, an ethyl group, an n-propyl group, an isopropyl group, an
n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl
group, an n-hexyl group, a cyclohexyl group, an n-octyl group, a
2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-lauryl
group and an n-stearyl group. In order to prevent the reduction in
a dry etching rate, a straight chain or branched alkyl group having
from 1 to 6 carbon atoms, for example, a methyl group, an ethyl
group, an n-propyl group, an isopropyl group, an n-butyl group, an
isobutyl group, a tert-butyl group, an n-pentyl group and an
n-hexyl group, a 2-hydroxyethyl group, an allyl group, a
2,3-dichloropropyl group and a 2,3-dibromopropul group are
particularly preferred.
[0051] Polymer (a) preferably has a glass transition temperature of
from 80 to 180.degree. C. in view of a coating ability,
film-forming property and thermal crosslinking property. When the
glass transition temperature of polymer (a) is lower than
80.degree. C., a problem of intermixing may tend to occur due to
disturbance of interface resulting from baking at the application
of a resist composition. On the other hand, if the glass transition
temperature of polymer (a) is higher than 180.degree. C., it may be
difficult to form a uniform coating. Also, a thermal crosslinking
property, specifically, diffusibility of an acid formed from a
thermally acid-generating agent of component (c) described in
detail hereinafter is adversely affected and thus, the problem of
intermixing may again tend to occur.
[0052] It is preferred that the polymer (a) dose not include an
aromatic carbon ring other than the dye structure described above
in the main chain thereof in view of preventing from the reduction
in a dry etching rate. Specifically, the main chain of polymer (a)
is preferably a vinyl polymer chain formed, e.g., from a
(meth)acrylate, a (meth)acrylamide, a vinyl ester or a vinyl ether,
a non-aromatic polyester chain, a non-aromatic polyurethane chain,
a non-aromatic polyamide chain, a non-aromatic polyether chain or a
non-aromatic polysulfone chain.
[0053] A polymer containing a repeating unit represented by the
following formula (IA) or (IIA) is preferred, since it is simply
synthesized and has a large film absorbance, good solubility to a
solvent and good dry etching property: 3
[0054] In the above formulae, R.sup.1 represents a hydrogen atom, a
methyl group, a chlorine atom, a bromine atom or a cyano group.
[0055] X in the formulae represents a divalent linking group,
preferably --CO.sub.2--, --CONH--, --O--, --CO--, --SO.sub.2--,
--NH--, --NR.sub.4--, a straight chain alkylene group having from 1
to 20 carbon atoms which may have a substituent, a branched
alkylene group having from 1 to 20 carbon atoms which may have a
substituent and a combination of two or more thereof. Suitable
examples of the substituent for the above described straight chain
or branched alkylene group include an alkyl group having from 1 to
10 carbon atoms, --OH, --OR.sub.4 (wherein R.sub.4 represents an
alkyl group having from 1 to 20 carbon atoms), --SR.sub.4,
--NR.sub.5R.sub.6 (wherein R.sub.5 and R.sub.6, which may be the
same or different, each represents a hydrogen atom or an alkyl
group having from 1 to 20 carbon atoms) and a halogen atom.
[0056] Particularly, --CO.sub.2-(a straight chain alkylene group
having from 1 to 8 carbon atoms which may have a substituent)-O--,
--CONH-(a straight chain alkylene group having from 1 to 8 carbon
atoms which may have a substituent)-O--, --CONR.sub.4-(a straight
chain alkylene group having from 1 to 8 carbon atoms which may have
a substituent)-O--, --CO.sub.2-(a straight chain alkylene group
having from 1 to 8 carbon atoms which may have a substituent)-NH--,
--CONH-(a straight chain alkylene group having from 1 to 8 carbon
atoms which may have a substituent)-NH-- and --CONR.sub.4-(a
straight chain alkylene group having from 1 to 8 carbon atoms which
may have a substituent)-NR.sub.5-- are preferred, since these are
easily synthesized. In the above formulae, R.sub.4, R.sub.5 and
R.sub.6 have the same meanings as described above,
respectively.
[0057] In the formulae (IA) and (IIA), Y, Z.sub.1, Z.sub.2, m and n
have the same meanings as defined in formulae (I) and (II) above,
respectively. When m and n each is 2 or 3, the Z.sub.1 groups or
Z.sub.2 groups may be the same or different.
[0058] Specific preferred examples of the repeating unit
represented by formula (IA) or (IIA) are set forth below, but the
present invention should not be construed as being limited thereto.
4
[0059] Polymer (a) used in the composition according to the present
invention may include a repeating unit of a non-light-absorbing
monomer in addition to the repeating unit represented by formula
(IA) or (IIA) in order to minutely control a dry etching rate, a
reflectivity or the like.
[0060] Examples of the non-light-absorbing monomer include
compounds having an addition-polymerizable unsaturated bond, for
example, an acrylic ester, a methacrylic ester, an acrylamide, a
methacrylamide, an allyl compound, a vinyl ether, a vinyl ester, a
styrene and a crotonic ester. Specific examples thereof
include:
[0061] Acrylic esters such as an alkyl acrylate (the alkyl group
preferably having from 1 to 10 carbon atoms) (e.g., methyl
acrylate, ethyl acrylate, propyl acrylate, tert-butyl acrylate,
amyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, octyl
acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl
acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl
acrylate, trimethylolpropane monoacrylate, pentaerythritol
monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl
acrylate, and tetrahydrofurfuryl acrylate) and an aryl acrylate
(e.g., phenyl acrylate, and hydroxyphenyl acrylate);
[0062] methacrylic esters such as an alkyl methacrylate (the alkyl
group preferably having from 1 to 10 carbon atoms) (e.g., methyl
methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl
methacrylate, tert-butyl methacrylate, amyl methacrylate, hexyl
methacrylate, cyclohexyl methacrylate, benzyl methacrylate,
chlorobenzyl methacrylate, octyl methacrylate, 2-hydroxyethyl
methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl
methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate,
trimethylolpropane monomethacrylate, pentaerythritol
monomethacrylate, furfuryl methacrylate, and tetra-hydrofurfuryl
methacrylate) and an aryl methacrylate (e.g., phenyl methacrylate,
hydroxyphenyl methacrylate, cresyl methacrylate, and naphthyl
methacrylate);
[0063] acrylamides such as acrylamide, an N-alkylacrylamide (the
alkyl group having from 1 to 10 carbon atoms and examples thereof
including a methyl group, an ethyl group, a propyl group, a butyl
group, a tert-butyl group, a heptenyl group, an octyl group, a
cyclohexyl group, a benzyl group, a hydroxyethyl group and a benzyl
group), an N-arylacrylamide (examples of the aryl group including a
phenyl group, a tolyl group, a nitrophenyl group, a naphthyl group,
a cyanophenyl group, a hydroxyphenyl group and a carboxyphenyl
group), an N,N-dialkylacrylamide (the alkyl group having from 1 to
10 carbon atoms and examples thereof including a methyl group, an
ethyl group, a butyl group, an isobutyl group, an ethylhexyl group
and a cyclohexyl group), an N,N-arylacrylamide (examples of the
aryl group including a phenyl group), N-methyl-N-phenylacrylamide,
N-hydroxyethyl-N-methylacrylamide and
N-2-acetoamidoethyl-N-acetylacrylam- ide;
[0064] methacrylamides such as methacrylamide, an
N-alkyl-methacrylamide (the alkyl group having from 1 to 10 carbon
atoms and examples thereof including a methyl group, an ethyl
group, a tert-butyl group, an ethylhexyl group, a hydroxyethyl
group and a cyclohexyl group), an N-arylmethacrylamide (examples of
the aryl group include a phenyl group, a hydroxyphenyl group and a
carboxyphenyl group), an N,N-dialkylmethacrylamide (examples of the
alkyl group including an ethyl group, a propyl group and a butyl
group), an N,N-diarylmethacrylamide (examples of the aryl group
include a phenyl group), N-hydroxyethyl-N-methylmethacrylamide,
N-methyl-N-phenylmethacrylamide and
N-ethyl-N-phenylmethacrylamide;
[0065] allyl compounds such as an allyl ester (e.g., allyl acetate,
allyl caproate, allyl caprylate, allyl laurate, allyl palmitate,
allyl stearate, allyl benzoate, allyl acetoacetate, and ally
lactate) and allyloxyethanol;
[0066] vinyl ethers such as an alkyl vinyl ether (e.g., hexyl vinyl
ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl
ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether,
chloroethyl vinyl ether, 1-methyl-2,2-dimethypropyl vinyl ether,
2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene
glycol vinyl ether, dimethylaminoethyl vinyl ether,
diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl
vinyl ether, and tetrahydrofurfuryl vinyl ether), a vinylaryl ether
(e.g., vinylphenyl ether, vinyltolyl ether, vinylchlorophenyl
ether, vinyl-2,4-dichlorophenyl ether, vinylnaphthyl ether, and
vinylanthranyl ether);
[0067] vinyl esters such as vinyl butyrate, vinyl isobutyrate,
vinyltrimethyl acetate, vinyldiethyl acetate, vinyl valerate, vinyl
caproate, vinyl chloroacetate, vinyl dichloroacetate, vinylmethoxy
acetate, vinylbutoxy acetate, vinylphenyl acetate, vinyl
acetoacetate, vinyl lactate, vinyl-.beta.-phenyl butyrate,
vinylcyclohexyl carboxylate, vinyl benzoate, vinyl salicylate,
vinyl chlorobenzoate, vinyl tetrachlorobenzoate and vinyl
naphthoate;
[0068] styrenes such as styrene, an alkylstyrene (e.g.,
methylstyrene, dimethylstyrene, trimethylstyrene, ethyl-styrene,
diethylstyrene, isopropylstyrene, butylstyrene, hexylstyrene,
cyclohexylstyrene, decylstyrene, benzyl-styrene,
chloromethylstyrene, trifluoromethylstyrene, ethoxymethylstyrene,
and acetoxymethylstyrene), an alkoxy-styrene (e.g., methoxystyrene,
4-methoxy-3-methylstyrene, and dimethoxystyrene), a halogenated
styrene (e.g., chlorostyrene, dichlorostyrene, trichlorostyrene,
tetra-chlorostyrene, pentachlorostyrene, bromostyrene,
dibromo-styrene, iodostyrene, fluorostyrene, trifluorostyrene,
2-bromo-4-trifluoromethylstyrene, and
4-fluoro-3-trifluoromethylstyrene), a hydroxystyrene (e.g.,
4-hydroxy-styrene, 3-hydroxystyrene, 2-hydroxystyrene,
4-hydroxy-3-methylstyrene, 4-hydroxy-3,5-dimethylstyrene,
4-hydroxy-3-methoxystyrene, and
4-hydroxy-3-(2-hydroxybenzyl)styrene), and carboxystyrene;
[0069] crotonic acid esters such as an alkyl crotonate (e.g., butyl
crotonate, hexyl crotonate, and glycerol mono-crotonate);
[0070] dialkyl itaconates (e.g., dimethyl itaconate, diethyl
itaconate, and dibutyl itaconate);
[0071] dialkyl esters of maleic acid or fumaric acid (e.g.,
dimethyl maleate, and dibutyl fumarate) or monoalkyl esters of
maleic acid or fumaric acid;
[0072] acrylic acid, methacrylic acid, crotonic acid, itaconic
acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile
and maleylonitrile. In addition, an addition-polymerizable
unsaturated compound capable of copolymerization with the repeating
unit for use in the present invention may be used. The
non-light-absorbing monomers can be employed individually or in a
combination of two or more thereof.
[0073] Among these, in view of the capability of intensifying the
thermal cross-linking property of polymer (a), monomers having a
hydroxy group, for example, 2-hydroxyethyl (meth)acrylate,
2-hydroxypropyl (meth)acrylate, ethylene glycol mono(meth)acrylate,
polyethylene glycol mono(meth)acrylate, propylene glycol
mono(meth)acrylate and polypropylene glycol mono(meth)acrylate,
corresponding (meth)acrylamide monomers having the hydroxy
group-containing moiety on the nitrogen atoms, vinyl alcohol,
hydroxystyrene and hydroxymethylstyrene are preferred.
[0074] From the standpoint that good solubility of the polymer to a
solvent can be maintained without the reduction of a dry etching
rate, an alkyl (meth)acrylate monomer containing the alkyl group
having from 1 to 10 carbon atoms is also preferred.
[0075] Further, polymer (a) may contain a crosslinking group in the
polymer chain thereof. For example, polymer (a) may contain a
repeating unit having a crosslinking group, represented by the
following formula (A), (B) or (C): 5
[0076] In formulae (A), (B) and (C), R.sup.2 represents a hydrogen
atom, a methyl group, a chlorine atom, a bromine atom or a cyano
group, and A represents a functional group having a --CH.sub.2OH,
--CH.sub.2OR.sup.14 or --CH.sub.2OCOCH.sub.3 terminal group
(wherein R.sup.14 represents a hydrocarbon group having from 1 to
20 carbon atoms). A is preferably --CONHCH.sub.2OH,
--CONHCH.sub.2OCH.sub.3, --CH.sub.2OCOCH.sub.3,
--C.sub.6H.sub.4CH.sub.2OH, --C.sub.6H.sub.4CH.sub.2OCH.sub.3 or a
group resulting from a reaction of
--CONHC(CH.sub.3).sub.2CH.sub.2COCH.sub.3 with formalin.
[0077] B represents a functional group having a --CO.sub.2H
terminal group, preferably --CO.sub.2H or
--C.sub.6H.sub.4CO.sub.2H.
[0078] D represents a functional group having an epoxy terminal
group, preferably a group shown below: 6
[0079] In polymer (a), the content of the repeating unit having the
dye structure (preferably the repeating unit having the dye
structure represented by formula (I) or (II)) is preferably from 10
to 100% by weight, more preferably from 30 to 97% by weight, and
yet more preferably from 50 to 95% by weight.
[0080] The content of the unit derived from a non-light-absorbing
monomer in polymer (a) is preferably from 0 to 50% by weight, more
preferably from 10 to 30% by weight.
[0081] The content of the unit derived from a monomer having a
crosslinking group in polymer (a) is preferably from 0 to 50% by
weight, more preferably from 10 to 30% by weight.
[0082] Specific examples of the polymer used in the present
invention are set forth below, but the present invention should not
be construed as being limited thereto. 7
[0083] Polymer (a) for use in the composition according to the
present invention can be synthesized by radical polymerization,
anion polymerization or cation polymerization. Various methods, for
example, a solution polymerization method, a suspension
polymerization method, an emulsion polymerization method and a bulk
polymerization method can be employed.
[0084] The molecular weight of polymer (a) may be varied depending
on various factors, for example, a coating solvent used, a solution
viscosity required and a coating shape required. However, the
weight average molecular weight thereof measured by gel permeation
chromatography and calculated in terms of polystyrene is ordinarily
from 1,000 to 1,000,000, preferably from 2,000 to 300,000, and more
preferably from 3,000 to 200,000.
[0085] The content of polymer (a) in the bottom anti-reflective
coating material composition according to the invention is
preferably from 50 to 90% by weight, more preferably from 70 to 90%
by weight, based on the total solid contents.
[0086] Now, the thermal crosslinking agent of component (b) will be
described in more detail below.
[0087] Component (b) in the composition is a thermal crosslinking
agent (hereinafter also referred to as thermal crosslinking agent
(b) sometimes) which is activated by an acid to react with
component (a) described above, thereby forming a crosslinked
structure. Preferred examples of the thermal crosslinking agent
include a melamine, benzoguanamine, glycoluril or urea compound
substituted with at least one substituent selected from a methylol
group, an alkoxymethyl group and an acyloxymethyl group.
[0088] Specific examples of the alkoxymethyl group includes
methoxymethyl, ethoxymethyl, propoxymethyl and butoxymethyl.
[0089] Specific examples of the acyloxymethyl group includes
acetyloxymethyl.
[0090] The number of methylol, alkoxymethyl and acyloxymethyl
groups contained in the compound is varied depending on the
compound having these substituents, but, it is from 2 to 6,
preferably from 5 to 6, per molecule in case of the melamine
compound, from 2 to 4, preferably from 3 to 4, per molecule in case
of the glycoluril compound and benzoguanamine compound, and from 3
to 4 per molecule in case of the urea compound.
[0091] On these compounds, hexamethoxymethylmelamine,
tetramethoxymethylbenzoguanamine and tetramethoxy-methylglycoluril
are particularly preferred in view of a thermal crosslinking
property and storage stability.
[0092] The methylol group-containing compound can be obtained by
reacting melamine, benzoguanamine, glycoluril or urea with formalin
in the presence of a basic catalyst, for example, sodium hydroxide,
potassium hydroxide, ammonia or a tetraalkylammonium hydroxide.
[0093] The alkoxymethyl group-containing compound can be obtained
by heating the methylol group-containing compound in an alcohol in
the presence of an acid catalyst, for example, hydrochloric acid,
sulfuric acid, nitric acid or methanesulfonic acid.
[0094] The acyloxymethyl group-containing compound can be obtained
by reacting the methylol group-containing compound with an acid
anhydride or acid halide in the presence of a basic catalyst.
[0095] The content of thermal crosslinking agent (b) in the bottom
anti-reflective coating material composition according to the
invention is ordinarily from 2 to 50% by weight, preferably from 5
to 30% by weight, based on the total solid contents.
[0096] Now, the sulfonic acid ester compound or diaryl iodonium
salt (hereinafter also referred to as thermally acid-generating
agent (c) sometimes) of component (c) will be described in more
detail below.
[0097] Component (c) is a compound which is decomposed with heating
to generate an acid that accelerates the thermal crosslinking
reaction between polymer (a) and thermal crosslinking agent
(b).
[0098] The inventors have been investigated various thermally
acid-generating agents and as a result, it has been found that a
compound which is decomposed to generate an acid at temperature
between 150 to 200.degree. C. is suitable for use in the bottom
anti-reflective coating material composition for a photoresist.
Thermally acid-generating agents having the decomposition
temperature of lower than 150.degree. C. are disadvantageous in
view of storage stability. Specifically, these compounds cause the
crosslinking reaction to increase the molecular weight thereof
during storage of the composition and thus, a coating ability of
the composition is deteriorated. On the other hand, thermally
acid-generating agents having the decomposition temperature of
higher than 200.degree. C. are also not suitable, since they need
high temperature for the crosslinking, which is inefficient, and
unevenness of crosslinking tends to occur in the resulting
coating.
[0099] The temperature at which the thermally acid-generating agent
used as component (c) initiates to generate an acid with heating is
from 150 to 200.degree. C., preferably from 170 to 190.degree.
C.
[0100] Of the thermally acid-generating agents of component (c),
the sulfonic acid ester compound is preferably an organic sulfonic
acid ester having from 3 to 20 carbon atoms, and specifically
includes a sulfonic acid ester of a secondary alcohol such as
2-propanol or 1-methoxy-2-propanol.
[0101] The diaryl iodonium salt includes a salt of a diaryl
iodonium cation with an organic sulfonic acid anion, SbF.sub.6
anion, PF.sub.6 anion or AsF.sub.6 anion. The organic sulfonic acid
anion is preferred as the anion.
[0102] Specific examples of the diaryl iodonium salt are set forth
below, but the present invention should not be construed as being
limited thereto. 8
[0103] Of these compounds, a salt of a diaryl iodonium cation with
an organic sulfonic acid anion is preferred in view of stability
and solubility to a solvent.
[0104] Further, a salt of a diaryl iodonium cation having a
straight chain or branched alkyl group having from 1 to 12 carbon
atoms or an alkoxy group having from 1 to 12 carbon atoms as a
substituent on the aryl group thereof with an organic sulfonic acid
anion is preferred also in view of safety. Specific examples of the
straight chain or branched alkyl group having from 1 to 12 carbon
atoms or alkoxy group having from 1 to 12 carbon atoms include a
methyl group, an ethyl group, an n-propyl group, an isopropyl
group, an n-butyl group, a sec-butyl group, an isobutyl group, a
tert-butyl group, an n-amyl group, an isoamyl group, a tert-amyl
group, an n-hexyl group, an n-heptyl group, an n-octyl group, a
2-ethylhexyl group, an n-decyl group, an n-dodecyl group, a
cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a
methoxy group, an ethoxy group, a propoxy group and a butoxy group.
Specific examples of the aryl group in diaryl iodonium include a
phenyl group, a naphthyl group, an anthryl group and a phenanthryl
group.
[0105] Of the organic sulfonic acid anions,
trifluoro-methanesulfonato, methanesulfonato and an arylsulfonato
which may have a straight chain or branched alkyl group having from
1 to 12 carbon atoms (including specifically those described
above), an alkoxy group having from 1 to 12 carbon atoms(including
specifically those described above) or a halogen atom, as a
substituent on the aryl group thereof are preferred in view of
solubility to a solvent. The aryl group of the arylsulfonato
specifically includes those described above.
[0106] Thermally acid-generating agents (c) can be employed
individually or in a combination of two or more thereof.
[0107] Thermally acid-generating agent (c) is employed, in terms of
a solid basis, ordinarily from 0.5 to 10 parts by weight,
preferably from 1 to 5 parts by weight, based on 100 parts by
weight of the bottom anti-reflective coating material composition
according to the invention.
[0108] In the composition of the present invention, a polymer
having both the function of polymer (a) as described above and the
function of thermally acid-generating agent (c) as described above
is preferably used.
[0109] Such a polymer includes a polymer (hereinafter also referred
to as polymer (a') sometimes) containing a repeating unit including
a dye structure having a molar extinction coefficient of
1.0.times.10.sup.4 or more to light including a wavelength used for
exposure of the photoresist and a repeating unit including a
sulfonic acid ester structure or diaryl iodonium structure, which
is decomposed to generate an acid with heating at temperature
between 150 to 200.degree. C.
[0110] Polymer (a') is a polymer having the structure capable of
generating an acid with heating connected to a polymer chain of the
light-absorbing polymer.
[0111] The structure capable of generating an acid with heating is
preferably bonded to a repeating unit constituting polymer (a').
Such a repeating unit includes a repeating unit constituting the
above described polymer and containing the above described dye
structure.
[0112] The sulfonic acid ester structure or diaryl iodonium
structure suitable for polymer (a') includes those of thermally
acid-generating agents (c) described above and the sulfonic acid
ester structure or diaryl iodonium structure is connected to the
repeating unit in any position thereof.
[0113] Specific examples of the repeating unit having the sulfonic
acid ester structure or diaryl iodonium structure are set forth
below. 9
[0114] With respect to the repeating unit including a dye
structure, other copolymerizing components, a content of each
repeating unit, glass transition temperature, weight average
molecular weight and other physical properties of the polymer (a'),
the descriptions on those for polymer (a) above are fully
applied.
[0115] Synthesis of polymer (a') can be conducted by addition
polymerization such as radical polymerization, cation
polymerization or anion polymerization or condensation
polymerization of a monomer including a dye structure and a monomer
including a thermally acid-generating structure.
[0116] The content of the repeating unit including the sulfonic
acid ester structure or diaryl iodonium structure in polymer (a')
is ordinarily from 1 to 10% by weight, preferably from 2 to 5% by
weight, based on the whole repeating units.
[0117] Further, polymer (a') may contain a non-light-absorbing
monomer and a thermal crosslinking monomer as copolymer components
for the same reason as described in the case of polymer (a).
[0118] In case of using polymer (a'), thermal crosslinking agent
(b) is also employed in an amount same as that described for
polymer (a). On the other hand, thermally acid-generating agent (c)
is not always necessarily used. However, in some cases, it is
preferred to additionally use thermally acid-generating agent (c)
for obtaining good results depending on the amount of the thermally
acid-generating structure contained in polymer (a').
[0119] The bottom anti-reflective coating material composition for
a photoresist according to the present invention may contain an
additional light absorbent, an adhesion aid or a surface active
agent, if desired.
[0120] Suitable examples of the light absorbent include anthracene
and a derivative thereof, .beta.-carbonylnaphtalene and a
derivative thereof, benzophenone and a derivative thereof,
phenanthrene and a derivative thereof, quinoline and a derivative
thereof, acridine and a derivative thereof, and thioxanthone and a
derivative thereof.
[0121] Specific examples thereof include anthracene,
9-hydroxymethylanthracene, 9-carboxyanthracene, 2-naphthoic acid,
1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid,
7-methoxy-3-hydroxy-2-naphthoic acid, benzophenone,
2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone,
2,3,4-trihydroxybenzophenone, phenanthrene, hydroxy-phenanthrene,
quinoline, N-phenylacridine, thioxanthone and
diethylthioxanthone.
[0122] The light absorbent is ordinarily employed in a proportion
of 30 parts by weight or less, preferably 20 parts by weight or
less, per 100 parts by weight of the bottom anti-reflective coating
material composition.
[0123] The adhesion aid is added mainly for the purpose of
improving the adhesion between the bottom anti-reflective coating
composition and a substrate or a resist, particularly for
preventing from peeling of the resist in an etching process.
Specific examples of the adhesion aid include chlorosilanes such as
trimethylchlorosilane, dimethylvinylchlorosilane,
methyldiphenylchlorosilane and chloromethyldimethylchlorosilnae,
alkoxysilanes such as trimethylmethoxysilane,
dimethyldiethoxysilane, methyl-dimethoxysilane,
dimethylvinylethoxysilane, diphenyl-dimethoxysilane and
phenyltriethoxysilane, silazanes such as hexamethyldisilazane,
N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine and
trimethylsilylimidazole, silanes such as vinyltrichlorosilane,
.gamma.-chloro-propyltrimethoxysilane,
.gamma.-aminopropyltriethoxysilane and
.gamma.-glycidoxypropyltrimethoxysilane, heterocyclic compounds
such as benzotriazole, benzimidazole, indazole, imidazole,
2-mercaptobenzimidazole, 2-mercaptobenzothiazole,
2-mercaptobenzoxazole, urazolthiouracil, mercaptoimidazole and
mercaptopyrimidine, and ureas and thiourea compounds such as
1,1-dimethylurea and 1,3-dimethylurea.
[0124] The adhesion aid is ordinarily employed in a proportion of
less than 10 parts by weight, preferably less than 5 parts by
weight, per 100 parts by weight of the bottom anti-reflective
coating material composition.
[0125] The bottom anti-reflective coating material composition of
the present invention may contain a surface active agent so as to
further improve the coating ability such as to prevent
striation.
[0126] Suitable examples of the surface active agent include
nonionic surface active agents such as polyoxyethylene alkyl ethers
(e.g., polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,
polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether),
polyoxyethylene alkylaryl ethers (e.g., polyoxyethylene octylphenyl
ether, and polyoxyethylene nonylphenyl ether),
polyoxyethylenepolyoxyprop- ylene block copolymers, sorbitan fatty
acid esters (e.g., sorbitan monolaurate, sorbitan monopalmitate,
sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and
sorbitan tristearate), and polyoxyethylenesorbitan fatty acid
esters (e.g., polyoxyethylene-sorbitan monolaurate,
polyoxyethylenesorbitan monopalmitate, polyoxyethylenesorbitan
monostearate, polyoxyethylene-sorbitan trioleate, and
polyoxyethylenesorbitan tristearate), fluorine-base surface active
agents such as Eftop EF301, EF303 and EF352 (all produced by Shin
Akita Kasei KK), Megafac F171 and F173 (both produced by Dainippon
Ink and Chemicals, Inc.), Florad FC430 and FC431 (both produced by
Sumitomo 3M KK), Asahiguard AG710, and Surflon S-382, SC101, SC102,
SC103, SC104, SC105 and SC106 (all produced by Asahi Glass Co.,
Ltd.), Organosiloxane Polymer KP341 (produced by Shin-Etsu Chemical
Co., Ltd.), and an acrylic acid-base or methacrylic acid-base
(co)polymer such as Polyflow No. 75 and 95 (both produced by
Kyoeisha Chemical Co., Ltd.). Among these surface active agents, a
fluorine-base surface active agent and a silicon-base surface
active agent are preferred. The surface active agent is ordinarily
employed in a proportion of 2 parts by weight or less, preferably 1
part by weight or less, per 100 parts by weight of the solid
content in the composition of the present invention.
[0127] The surface active agents can be employed individually or in
a combination of two or more thereof.
[0128] Now, the organic solvent (hereinafter also referred to as
solvent (d) sometimes) of component (d) of the bottom
anti-reflective coating material composition according to the
present invention will be described in more detail below.
[0129] Suitable examples of solvent (d) include ethylene glycol
monomethyl ether, ethylene glycol monoethyl ether, methyl
cellosolve acetate, ethyl cellosolve acetate, diethylene glycol
monomethyl ether, diethylene glycol monoethyl ether, propylene
glycol methylether acetate, propylene glycol propylether acetate,
toluene, xylene, methyl ethyl ketone, cyclopentanone,
cyclohexanone, ethyl 2-hydroxypropionate, ethyl
2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl
hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl
3-methoxypropionate, ethyl 3-methoxypropionate, ethyl
3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate,
ethyl pyruvate, ethyl acetate and butyl acetate. The organic
solvents can be used individually or in a combination of two or
more thereof.
[0130] Further, a high boiling point solvent such as
N-methylformamide, N,N-dimethylformamide, N-methylacetamide,
N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide and
benzyl ethyl ether may be used in combination.
[0131] Among these solvents, propylene glycol methyl ether acetate
and ethyl 3-ethoxypropionate are preferred in view of safety.
[0132] A resist coated on the bottom anti-reflective coating
material composition according to the present invention may be
either negative or positive. A chemical amplification type resist
comprising a photo-acid generator and a binder having a group
capable of being decomposed by an acid to increase an alkali
dissolution rate, a chemical amplification type resist comprising
an alkali soluble binder, a photo-acid generator and a low
molecular weight compound capable of being decomposed by an acid to
increase an alkali dissolution rate of the resist, or a chemical
amplification type resist comprising a photo-acid generator, a
binder having a group capable of being decomposed by an acid to
increase an alkali dissolution rate and a low molecular weight
compound capable of being decomposed by an acid to increase an
alkali dissolution rate of the resist can be suitably used.
Specific examples thereof include FKR-321BC and ARCH-2 both
manufactured by Fuji Film Olin Co., Ltd.
[0133] Examples of a developer suitable for a photoresist in case
of using the bottom anti-reflective coating material composition
for a photoresist of the present invention, include an aqueous
solution of an alkali, for example, an inorganic alkali such as
sodium hydroxide, potassium hydroxide, sodium carbonate, sodium
silicate, sodium metasilicate and aqueous ammonia, a primary amine
such as ethylamine and n-propylamine, a secondary amine such as
diethylamine and di-n-butylamine, a tertiary amine such as
triethylamine and methyldiethylamine, an alcohol amine such as
dimethylethanolamine and triethanolamine, a quaternary ammonium
salt such as tetramethylammonium hydroxide, tetraethylammonium
hydroxide and choline, and a cyclic amine such as pyrrole and
piperazine. Further, an alcohol such as isopropyl alcohol or a
surface active agent such as a nonionic surface active agent may be
added to use to the aqueous solution of alkali in an appropriate
amount.
[0134] Among the above-described a developers, a quaternary
ammonium salt is preferred, and tetramethylammonium hydroxide and
chlorine are more preferred.
[0135] The bottom anti-reflective coating material composition of
the present invention is coated on a substrate (for example, a
transparent substrate such as a silicon/silicon dioxide coating, a
glass substrate and an ITO substrate) as used in the production of
a precision integrated circuit element by an appropriate coating
method using a device such as a spinner or a coater. Then, the
coating was baked to cure the bottom anti-reflective coating
material composition, thereby forming a bottom anti-reflective
coating. The bottom anti-reflective coating preferably has a
thickness of form 0.01 to 3.0 .mu.m. the baking after the coating
is preferably performed at a temperature of from 80 to 250.degree.
C. for from 1 to 120 minutes. On the thus-obtained anti-reflective
coating, a photoresist composition is coated, then exposed through
a predetermined mask to light, for example, KrF excimer laser light
having a wavelength of 248 nm, developed, rinsed and dried to
obtain a good resist pattern. After the exposure, heating (post
exposure bake: PEB) is performed, if desired.
[0136] According to the bottom anti-reflective coating material
composition for a photoresist and the method of forming a resist
pattern using the same of the present invention, a bottom
anti-reflective coating having a large absorbance to light
including a wavelength used for exposure is formed, an adverse
effect due to a standing wave generated by reflection from a
substrate can be reduced, a limiting resolution of the photoresist
is increased, and a good resist profile is obtained.
[0137] The present invention will be described in greater detail
with reference to the following examples, but the present invention
should not be construed as being limited thereto.
[0138] A molar extinction coefficient of the dye structure linking
to a polymer was measured in the following manner.
[0139] Specifically, a low molecular weight compound having the dye
structure substantially exhibiting a light-absorbing property was
dissolved in a solvent capable of dissolving the low molecular
weight compound, an absorption spectrum of the solution was
measured by means of an ultraviolet-visible spectrophotometer, and
a molar extinction coefficient was obtained according to Beer's
low.
SYNTHETIC EXAMPLE 1
[0140] Synthesis of Polymer (11)
[0141] Synthesis of Monomer
[0142] 130 g of 2-hydroxyethyl methacrylate and 190.5 g of
2-chloronaphthoyl were added to 600 ml of acetone and thereto was
added dropwise 101 g of triethylamine. The mixture was reacted at
40.degree. C. for 4 hours, 2 liters of distilled water was added
thereto, and the product precipitated was collected by decantation.
The product was purified by silica gel column chromatography.
Yield: 75%.
[0143] Synthesis of Polymer
[0144] 10 g of the monomer prepared above and 31 g of
2-hydroxyethyl methacrylate were dissolved in 60 g of
dimethylformamide (DMF), the reaction solution was then heated at
65.degree. C. and at the same time, nitrogen gas was blown into the
reaction solution for 30 minutes. 50 mg of V-65 (manufactured by
Wako Pure Chemical Industries, Ltd.) as a polymerization initiator
was added thereto three times every two hours. The reaction product
was reprecipitated in one liter of distilled water to recover
Polymer (11) as powder. The polymer obtained was subjected to GPC
analysis and it was found to have a weight average molecular
weight, in terms of standard polystyrene, of 34,000.
[0145] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
108.degree. C. The dye structure included in Polymer (11) exhibited
a molar extinction coefficient of 6.1.times.10.sup.4 to light
having a wavelength of 248 nm.
SYNTHETIC EXAMPLE 2
[0146] Synthesis of Polymer (14)
[0147] Synthesis of Monomer
[0148] 144 g of 2-hydroxypropyl methacrylate and 190.5 g of
2-chloronaphthoyl were added to 600 ml of acetone and thereto was
added dropwise 101 g of triethylamine. The mixture was reacted at
40.degree. C. for 4 hours, 2 liters of distilled water was added
thereto, and the product precipitated was collected by decantation.
The product was purified by silica gel column chromatography.
Yield: 80%.
[0149] Synthesis of Polymer
[0150] 12 g of the monomer prepared above and 3 g of
2-hydroxypropyl methacrylate were dissolved in 60 g of DMF, the
reaction solution was then heated at 65.degree. C. and at the same
time, nitrogen gas was blown into the reaction solution for 30
minutes. 50 mg of V-65 (manufactured by Wako Pure Chemical
Industries, Ltd.) as a polymerization initiator was added thereto
three times every two hours. The reaction product was
reprecipitated in one liter of distilled water to recover Polymer
(14) as powder. The polymer obtained was subjected to GPC analysis
and it was found to have a weight average molecular weight, in
terms of standard polystyrene, of 22,000.
[0151] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
128.degree. C. The dye structure included in Polymer (14) exhibited
a molar extinction coefficient of 6.1.times.10.sup.4 to light
having a wavelength of 248 nm.
SYNTHETIC EXAMPLE 3
[0152] Synthesis of Polymer (15)
[0153] Synthesis of Monomer
[0154] 142 g of glycidyl methacrylate, 172 g of 2-naphthoic acid
and 0.5 g of methoxyhydroquinone were added to 600 ml of acetone
and thereto was added dropwise 101 g of triethylamine. The mixture
was reacted at 70.degree. C. for 4 hours, 2 liters of distilled
water was added thereto, and the product precipitated was collected
by decantation. The product was purified by silica gel column
chromatography. Yield: 80%.
[0155] Synthesis of Polymer
[0156] 12 g of the monomer prepared above and 3 g of 2-hydroxyethyl
methacrylate were dissolved in 60 g of DMF, the reaction solution
was then heated at 65.degree. C. and at the same time, nitrogen gas
was blown into the reaction solution for 30 minutes. 50 mg of V-65
(manufactured by Wako Pure Chemical Industries, Ltd.) as a
polymerization initiator was added thereto three times every two
hours. The reaction product was reprecipitated in one liter of
distilled water to recover Polymer (15) as powder. The polymer
obtained was subjected to GPC analysis and it was found to have a
weight average molecular weight, in terms of standard polystyrene,
of 19,000.
[0157] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
138.degree. C. The dye structure included in Polymer (15) exhibited
a molar extinction coefficient of 6.3.times.10.sup.4 to light
having a wavelength of 248 nm.
SYNTHESIS EXAMPLE 4
[0158] Synthesis of Polymer (16)
[0159] Synthesis of Monomer
[0160] 128 g of glycidyl methacrylate, 188 g of
3-hydroxy-2-naphtoic acid and 0.5 g of methoxyhydroquinone were
added to 600 ml of acetone and thereto was added dropwise 101 g of
triethylamine. The mixture was reacted at 70.degree. C. for 4
hours, 2 liters of distilled water was added thereto, and the
product precipitated was collected by decantation. The product was
purified by silica gel column chromatography. Yield: 80%.
[0161] Synthesis of Polymer
[0162] 12 g of the monomer prepared above and 3 g of 2-hydroxyethyl
acrylate were dissolved in 60 g of DMF, the reaction solution was
heated at 650C and at the same time, nitrogen gas was blown into
the reaction solution for 30 minutes. 50 mg of V-65 (manufactured
by Wako Pure Chemical Industries, Ltd.) as a polymerization
initiator was added thereto three times every two hours. The
reaction product was reprecipitated in one liter of distilled water
to recover Polymer (16) as powder. The polymer obtained was
subjected to GPC analysis and it was found to have a weight average
molecular weight, in terms of standard polystyrene, of 19,000.
[0163] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
128.degree. C. The dye structure included in Polymer (16) exhibited
a molar extinction coefficient of 7.9.times.10.sup.4 to light
having a wavelength of 248 nm.
SYNTHESIS EXAMPLE 5
[0164] Synthesis of Polymer (17)
[0165] Synthesis of Monomer
[0166] 142 g of glycidyl methacrylate, 218 g of
3-hydroxy-7-methoxy-2-naph- toic acid and 0.5 g of
methoxyhydroquinone were added to 600 ml of acetone and thereto was
added dropwise 101 g of triethylamine. The mixture was reacted at
70.degree. C. for 4 hours, 2 liters of distilled water was added
thereto, and the product precipitated was collected by decantation.
The product was purified by silica gel column chromatography.
Yield: 85%.
[0167] Synthesis of Polymer
[0168] 12 g of the monomer prepared above and 3 g of 2-hydroxyethyl
methacrylate were dissolved in 60 g of DMF, the reaction solution
was heated at 65.degree. C. and at the same time, nitrogen gas was
blown into the reaction solution for 30 minutes. 50 mg of V-65
(manufactured by Wako Pure Chemical Industries, Ltd.) as a
polymerization initiator was added thereto three times every two
hours. The reaction product was reprecipitated in one liter of
distilled water to recover Polymer (17) as powder. The polymer
obtained was subjected to GPC analysis and it was found to have a
weight average molecular weight, in terms of standard polystyrene,
of 31,000.
[0169] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
105.degree. C. The dye structure included in Polymer (17) exhibited
a molar extinction coefficient of 8.5.times.10.sup.4 to light
having a wavelength of 248 nm.
SYNTHESIS EXAMPLE 6
[0170] Synthesis of Polymer (18)
[0171] Synthesis of Monomer
[0172] 142 g of glycidyl methacrylate, 204 g of
3,7-dihydroxy-2-naphtoic acid and 0.5 g of methoxyhydroquinone were
added to 600 ml of acetone and thereto was added dropwise 101 g of
triethylamine. The mixture was reacted at 70.degree. C. for 4
hours, 2 liters of distilled water was added thereto, and the
product precipitated was collected by decantation. The product was
purified by silica gel column chromatography. Yield: 62%.
[0173] Synthesis of Polymer
[0174] 12 g of the monomer prepared above and 3 g of
2-hydroxypropyl methacrylate were dissolved in 60 g of DMF, the
reaction solution was heated at 65.degree. C. and at the same time,
nitrogen gas was blown into the reaction solution for 30 minutes.
50 mg of V-65 (manufactured by Wako Pure Chemical Industries, Ltd.)
as a polymerization initiator was added thereto three times every
two hours. The reaction product was reprecipitated in one liter of
distilled water to recover Polymer (18) as powder. The polymer
obtained was subjected to GPC analysis and it was found to have a
weight average molecular weight, in terms of standard polystyrene,
of 27,000.
[0175] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
110.degree. C. The dye structure included in Polymer (18) exhibited
a molar extinction coefficient of 8.9.times.10.sup.4 to light
having a wavelength of 248 nm.
SYNTHESIS EXAMPLE 7
[0176] Synthesis of Comparative Polymer (1)
[0177] Synthesis of Monomer
[0178] 160 g of triethylene glycol acrylate and 190.5 g of
2-chloronaphtholy were added to 600 ml of acetone and thereto was
added dropwise 101 g of triethylamine. The mixture was reacted at
40.degree. C. for 4 hours, 2 liters of distilled water was added
thereto, and the product precipitated was collected by decantation.
The product was purified by silica gel column chromatography.
Yield: 80%.
[0179] Synthesis of Polymer
[0180] 12 g of the monomer prepared above and 3 g of 2-hydroxyethyl
acrylate were dissolved in 60 g of DMF, the reaction solution was
heated at 65.degree. C. and at the same time, nitrogen gas was
blown into the reaction solution for 30 minutes. 150 mg of. V-65
(manufactured by Wako Pure Chemical Industries, Ltd.) as a
polymerization initiator was added thereto three times every two
hours. The reaction product was reprecipitated in one liter of
distilled water to recover Comparative Polymer (1) as powder. The
polymer obtained was subjected to GPC analysis and it was found to
have a weight average molecular weight, in terms of standard
polystyrene, of 28,000.
[0181] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
62.degree. C. The dye structure included in Comparative Polymer (1)
exhibited a molar extinction coefficient of 6.1.times.10.sup.4 to
light having a wavelength of 248 nm.
[0182] Comparative Polymer (1) obtained had the following structure
units: 10
SYNTHESIS EXAMPLE 8
[0183] Synthesis of Comparative Polymer (2)
[0184] Synthesis of Monomer
[0185] To 198 g of 2,3-naphthalenedicarboxylic acid anhydride were
added 75g of 3-aminopropanol and 400 g of dioxane, and the mixture
was reacted at 80.degree. C. for 4 hours. 200 g of the resulting
imide compound was dissolved in 500 g of DMF, and to the solution
was added 74 g of methacryloyl chloride and then 72 g of
triethylamine was added dropwise. The mixture was reacted at
40.degree. C. for 4 hours, 2 liters of distilled water was added
thereto, and the product deposited was collected by filtration. The
product was recrystallized from a solvent mixture of DMF/water.
Yield: 72%.
[0186] Synthesis of Polymer
[0187] 12 g of the monomer prepared above and 4 g of glycidyl
methacrylate were dissolved in 60 g of DMF, the reaction solution
was heated at 65.degree. C. and at the same time, nitrogen gas was
blown into the reaction solution for 30 minutes. 50 mg of V-65
(manufactured by Wako Pure Chemical Industries, Ltd.) as a
polymerization initiator was added thereto three times every two
hours. The reaction product was reprecipitated in one liter of
distilled water to recover Comparative Polymer (2) as powder. The
polymer obtained was subjected to GPC analysis and it was found to
have a weight average molecular weight, in terms of standard
polystyrene, of 41,000.
[0188] A glass transition temperature of the polymer was measured
by means of differential scanning calorimetry using an apparatus
(DSC220C manufactured by Seiko Instruments Inc.) and it was
188.degree. C. The dye structure included in Comparative Polymer
(2) exhibited a molar extinction coefficient of 6.1.times.10.sup.4
to light having a wavelength of 248 nm.
[0189] Comparative Polymer (1) obtained had the following structure
units: 11
EXAMPLES 1 TO 8 AND COMPARATIVE EXAMPLES 1 TO 6
[0190] 17 g of each polymer light absorbent obtained in Synthesis
Examples described above, 2.5 g of hexamethoxymethylmelamine and
0.5 g of thermally acid-generating agent shown in Table 1 below
were dissolved in propylene glycol methylether acetate to prepare a
10% solution, and the solution was filtered through a microfilter
made of Teflon having a pore size of 0.10 .mu.m to prepare a bottom
anti-reflective coating solution. The solution was coated on a
silicon wafer by means of a spinner and heated on a vacuum contact
type hot plate at 205.degree. C. for one minute to form a bottom
anti-reflective coating having a thickness of 0.11 .mu.m. The
coating absorbance of the bottom anti-reflective coating to KrF
excimer laser light having a wavelength of 248 nm was determined by
providing the coating on a quartz wafer and measuring its
absorbance by means of an ultraviolet-visible
spectrophotometer.
[0191] In Comparative Examples 1 to 6, the thermally
acid-generating agent other than the compound defined in the
present invention, i.e., triphenylsulfonium tosylate (having a
thermally decomposing temperature of 220.degree. C.) or cyclohexyl
tosylate (having a thermally decomposing temperature of 140.degree.
C.) was used as component (c). On each bottom anti-reflective
coating obtained was coated a positive photoresist for KrF excimer
laser (FKR-321BC manufactured by Fuji Film Olin Co., Ltd.) to
prepare a photoresist layer having a thickness of 0.70 .mu.m. The
layer was exposed to KrF excimer laser light having a wavelength of
248 nm using a reduction projection exposure apparatus
(NSR-2205EX12B manufactured by Nikon Corp.), subjected to post
exposure baking at 110.degree. C. for 60 seconds, and developed
with a 2.38% aqueous solution of tetramethylammonium hydroxide for
60 seconds to prepare a resist pattern.
[0192] The thus-obtained resist pattern on the silicon wafer was
observed by means of a scanning electron microscope and evaluated
with limiting resolution, film thickness dependency and resist
profile, specifically, the occurrence of footing or undercut
resulting from intermixing.
[0193] The limiting resolution means limiting resolution at an
exposure amount necessary for reproducing a mask patter of 0.50
.mu.m when the film thickness is 0.70 .mu.m.
[0194] The film thickness dependency was evaluated using a ratio of
the limiting resolution with a resist film thickness of 0.70 .mu.m
to the limiting resolution with a resist film thickness of 0.73
.mu.m. A value closer to 1.0 is preferred.
[0195] The results obtained are shown in Table 2 below.
1TABLE 1 Compounds used in Examples and Comparative Examples
Polymer Thermally Example or Light Acid- Comparative Absorbent
Thermal Generating Example (a) Crosslinking Agent (b) Agent (c)
Example 1 Synthesis Hexamethoxymethylmelamine TAG14 Example 1
Example 2 Synthesis Hexamethoxymethylmelamine TAG10 Example 2
Example 3 Synthesis Hexamethoxymethylmelamine TAG18 Example 3
Example 4 Synthesis Hexamethoxymethylmelamine TAG17 Example 4
Example 5 Synthesis Hexamethoxymethylmelamine TAG18 Example 5
Example 6 Synthesis Hexamethoxymethylmelamine TAG21 Example 6
Example 7 Synthesis Hexamethoxymethylmelamine TAG21 Example 7
Example 8 Synthesis Hexamethoxymethylmelamine TAG21 Example 8
Comparative Synthesis Hexamethoxymethylmelamine Triphenyl- Example
1 Example 1 sulfonium tosylate Comparative Synthesis
Hexamethoxymethylmelamine Triphenyl- Example 2 Example 2 sulfonium
tosylate Comparative Synthesis Hexamethoxymethylmelamine Triphenyl-
Example 3 Example 3 sulfonium tosylate Comparative Synthesis
Hexamethoxymethylmelamine Cyclohexyl Example 4 Example 4 tosylate
Comparative Synthesis Hexamethoxymethylmelamine Cyclohexyl Example
5 Example 5 tosylate Comparative Synthesis
Hexamethoxymethylmelamine Cyclohexyl Example 6 Example 6
tosylate
[0196]
2TABLE 2 Coating Example or Absorbance Limiting Film Comparative at
248 nm Resolution Thickness Example (/.mu.m) (.mu.m) Dependency
Resist Profile Example 1 8.311 0.20 0.98 Good (rectangular) Example
2 8.373 0.20 0.98 Good (rectangular) Example 3 7.843 0.20 0.98 Good
(rectangular) Example 4 7.668 0.20 0.98 Good (rectangular) Example
5 8.041 0.20 0.98 Good (rectangular) Example 6 8.618 0.20 0.98 Good
(rectangular) Example 7 7.739 0.20 0.97 slight undercut Example 8
7.993 0.20 0.97 slight footing Comparative 7.637 0.23 0.97 Footing
Example 1 Comparative 7.711 0.22 0.97 Footing Example 2 Comparative
7.316 0.21 0.97 Footing Example 3 Comparative 7.816 0.21 0.97
Undercut Example 4 Comparative 8.153 0.22 0.97 Undercut Example 5
Comparative 8.127 0.21 0.97 Undercut Example 6
[0197] From the results shown in Table 2, it can be seen that the
large coating absorbance, improved limiting resolution of a
photoresist, excellent film thickness dependency of resolution due
to a standing wave resulting from the decrease in reflection from a
substrate, and good resist profile are obtained when the bottom
anti-reflective coating was formed using the bottom anti-reflective
coating material composition for a resist according to the present
invention.
[0198] While the invention has been described in detail and with
reference to specific embodiments thereof, it will be apparent to
one skilled in the art that various changes and modifications can
be made therein without departing from the spirit and scope
thereof.
* * * * *