Title: Chemical amplification type positive resist composition
Abstract: A chemical amplification type positive resist composition comprising:
- (A) a resin which itself is insoluble or poorly soluble in an alkali aqueous solution but becomes soluble in an alkali aqueous solution by the action of an acid, and which contains a structural unit derived from p-hydroxystyrene and a structural unit represented by the formula (Ia) or (Ib) ##STR1##
wherein R1 and R2 each independently represents hydrogen or methyl, and R3 to R5 each independently represents alkyl having 1 to 8 carbon atoms; and - (B) radiation-sensitive acid generator comprising sulfonic acid ester of N-hydroxyimide compound; and onium salt is provided.
Patent Number: 6,893,794 Issued on 05/17/2005 to Akita, et al.
| Inventors:
|
Akita; Makoto (Kusatsu, JP);
Yamaguchi; Satoshi (Toyonaka, JP)
|
| Assignee:
|
Sumitomo Chemical Company, Limited (Osaka, JP)
|
| Appl. No.:
|
622692 |
| Filed:
|
July 21, 2003 |
Foreign Application Priority Data
| Jul 25, 2002[JP] | 2002-216355 |
| Oct 25, 2002[JP] | 2002-311246 |
| Current U.S. Class: |
430/270.1; 430/905; 430/910 |
| Intern'l Class: |
G03F 007/00.4 |
| Field of Search: |
430/2701,905,910
|
References Cited [Referenced By]
U.S. Patent Documents
| 6013416 | Jan., 2000 | Nozaki et al.
| |
| 6692884 | Feb., 2004 | Fujimori et al.
| |
| 2003/0207201 | Nov., 2003 | Hatakeyama et al.
| |
| 2003/0224290 | Dec., 2003 | Kobayashi et al.
| |
| Foreign Patent Documents |
| 1 167 349 | Jan., 2002 | EP.
| |
| 1 225 479 | Jul., 2002 | EP.
| |
| 2002-49155 | Feb., 2002 | JP.
| |
Primary Examiner: Chu; John S.
Attorney, Agent or Firm: Birch, Stewart, Kolasch & Birch, LLP
Claims
1. A chemical amplification type positive resist composition comprising:
(A) a resin which itself is insoluble or poorly soluble in an alkali aqueous
solution but becomes soluble in an alkali aqueous solution by the action of an
acid, and which contains a structural unit derived from p-hydroxystyrene and a
structural unit represented by the formula (Ia) or (Ib)
##STR11##
wherein R
1 and R
2 each independently represents hydrogen
or methyl, and R
3 to R
5 each independently represents alkyl
having 1 to 8 carbon atoms; and
(B) radiation-sensitive acid generator comprising sulfonic acid ester of N-hydroxyimide
compound; and onium salt.
2. The composition according to claim 1, wherein said sulfonic acid ester of
N-hydroxyimide compound is a compound represented by the formula (II):
##STR12##
wherein R
6 represents arylene which may be substituted, alkylene which
may be substituted or alkenylene which may be substituted, and R
7 represents
alkyl which may be substituted or aryl which may be substituted.
3. The composition according to claim 1, wherein said onium salt is a salt represented
by the formula (IIIa) or (IIIb):
##STR13##
wherein P
1 to P
5 each independently represents hydrogen,
hydroxyl, alkyl having 1 to 6 carbon atoms or alkoxy having 1 to 6 carbon atoms,
X
- represents a counter ion.
4. The composition according to claim 3, wherein said counter ion X
-
is an ion represented by the following formula (IVa) or (IVb):
##STR14##
wherein p represents an integer of 1 to 8, and Q
1 to Q
5 each
independently represents hydrogen, hydroxyl, alkyl having 1 to 12 carbon atoms,
perfluoroalkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms,
electron-withdrawing group, or a group represented by the formula (V):
wherein Y represents alkylene having 1 to 16 carbon atoms in which —CH
2—
other than that binding to the adjacent —COO— group may be substituted
by —S— or —O—, and Z represents hydrogen or alicyclic
hydrocarbon having 3 to 20 carbon atoms.
5. The composition according to claim 3, wherein a weight ratio of the sulfonic
acid ester of N-hydroxyimide compound represented by the formula (II) to the total
onium salt of the formula (IIIa) and the formula (IIIb) is 9:1 to 1:9.
6. The composition according to claim 1, wherein the radiation-sensitive acid
generator (B) is contained at 0.3 to 50 parts by weight per 100 parts by weight
of the resin (A).
7. The composition according to claim 1, wherein a nitrogen-containing basic
organic compound is further contained as a quencher.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chemical amplification type resist composition
for use in microfabrication of semiconductor.
2. Prior Art
Semiconductor microfabrication employs a lithography process using
a resist composition. In lithography, theoretically, the shorter the exposure wavelength
becomes, the higher the resolution can be made, as expressed by Rayleigh's diffraction
limit formula. The wavelength of an exposure light source for lithography used
in the manufacture of semiconductor devices has been shortened year by year as
g-line having a wavelength of 436 nm, i-line having a wavelength of 365 nm, KrF
excimer laser having a wavelength of 248 nm and ArF excimer laser having a wavelength
of 193 nm. F
2 excimer laser having a wavelength of 157 nm seems to be
promising as the next-generation exposure light source. Further, as the exposure
light source of the subsequent generation, soft X ray (EUV) having a wavelength
of 13 nm or shorter has been proposed as the exposure light source following the
157 nm-wavelength F
2 excimer laser. As a somewhat different type of
lithography technology from above, the electron beam lithography has been intensively studied.
As the resists suitable for such light sources, the chemical amplification type
resists utilizing chemical amplification effect of acid catalysts have been proposed.
When a chemical amplification type resist is radiated, an acid is generated at
the radiated part from acid generator in the resist, and then the solubility of
the resist at the radiated part to alkali developing solution changes by heat treatment
called as post exposure bake, which may hereinafter be abbreviated as PEB, and
thereby the resist provides positive or negative patterns.
For a chemical amplification type positive resist, a resin in which an alkali
soluble group is protected by a group to be cleaved by the action of an acid is
frequently used in combination with an acid generator. It has been reported that
high resolution and good dry etching resistance are acquired when a protecting
group such as 2-alkyl-2-adamantyl group or 1-adamantyl-1-alkylalkyl group is used
as the group to be cleaved by the action of an acid (for example, JP 9-73173-A,
S. Takechi et al., J. Photopolym. Sci. Technol., Vol. 9, No. 3, 475-487 (1996)
etc.). In addition, a resist for electron beam utilizing a copolymer of 2-methyl-2-adamantyl
methacrylate or 2-ethyl-2-adamantyl methacrylate and hydroxystyrene is presented
and, in particular, a resist for electron beam utilizing a copolymer of 2-ethyl-2-adamantyl
methacrylate and hydroxystyrene has been reported to have high sensitivity, good
etching resistance and high resolution in KrF excimer laser exposure (for example,
Nozaki et al., J. Photopolym. Sci. Technol., Vol. 13, No. 3, 397-403 (2000)).
In electron beam lithography, however, sensitivity is low and throughput in production
of an integrated circuit is problematic when these resists are used as they are.
In this respect, it is desired to acquire high sensitivity for resist. However,
in general, when sensitivity of resist is enhanced, resolution deteriorates, and
smoothness of pattern shape as well as pattern profile (edge roughness) becomes
poor. Since large edge roughness of pattern exerts an influence on accuracy of
microfabrication, the edge roughness is desired to be smooth. Thus, the results
obtained with conventional resists cannot meet desirable performances in sensitivity,
resolution, pattern shape and the like.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a chemical amplification type
positive resist composition which possesses a high sensitivity and high resolution,
gives, in particular, greatly improved line edge roughness and is suitable for
electron beam lithography, EUV lithography and the like.
The present invention relates to the followings:
<1> A chemical amplification type positive resist composition comprising:
- (A) a resin which itself is insoluble or poorly soluble in an alkali
aqueous solution but becomes soluble in an alkali aqueous solution by the action
of an acid, and which contains a structural unit derived from p-hydroxystyrene
and a structural unit represented by the formula (Ia) or (Ib)
##STR2##
wherein R1 and R2 each independently represents hydrogen
or methyl, and R3 to R5 each independently represents alkyl
having 1 to 8 carbon atoms; and
- (B) radiation-sensitive acid generator comprising sulfonic acid ester
of N-hydroxyimide compound; and onium salt, which hereinafter referred to as "the
present composition".
<2> The composition according to <1>, wherein said
sulfonic acid ester of N-hydroxyimide compound is a compound represented by the
formula (II):
##STR3##
wherein R6 represents arylene which may be substituted, alkylene which may
be substituted or alkenylene which may be substituted, and R7 represents
alkyl which may be substituted or aryl which may be substituted.
<3> The composition according to <1> or <2>,
wherein said onium salt is a salt represented by the formula (IIIa) or (IIIb):
##STR4##
wherein P1 to P5 each independently represents hydrogen,
hydroxyl, alkyl having 1 to 6 carbon atoms or alkoxy having 1 to 6 carbon atoms,
X- represents a counter ion.
<4> The composition according to <3>, wherein said
counter ion X- is an ion represented by the following formula (IVa)
or (IVb):
##STR5##
wherein p represents an integer of 1 to 8, and Q1 to Q5 each
independently represents hydrogen, hydroxyl, alkyl having 1 to 12 carbon atoms,
perfluoroalkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms,
electron-withdrawing group, or a group represented by the formula (V):
wherein Y represents alkylene having 1 to 16 carbon atoms in which —CH2—
other than that binding to the adjacent —COO— group may be substituted
by —S— or —O—, and Z represents hydrogen or alicyclic
hydrocarbon having 3 to 20 carbon atoms.
<5> The composition according to any one of <2>
to <4>, wherein a weight ratio of the sulfonic acid ester of N-hydroxyimide
compound represented by the formula (II) to the total onium salt of the formulae
(IIIa) and (IIIb) is 9:1 to 1:9.
<6> The composition according to any one of <1>
to <5>, wherein the radiation-sensitive acid generator (B) is contained
at 0.3 to 50 parts by weight per 100 parts by weight of the resin (A).
<7> The composition according to any one of <1>
to <6>, wherein a nitrogen-containing basic organic compound is further
contained as a quencher.
DESCRIPTION OF PREFERRED EMBODIMENTS
The resin component in the present composition contains a structural unit having
an acid labile group and the resin component itself is insoluble or poorly soluble
in an alkali aqueous solution but becomes soluble in an alkali aqueous solution
by the action of an acid. The resin component contains a structural unit derived
from p-hydroxystyrene as well as at least one structural unit represented by the
above formula (Ia) or (Ib) as the structural unit having an labile group.
Examples of monomers for the structural unit represented by the formula
(Ia) or (Ib) include 2-alkyl-2-adamantyl (meth)acrylate and 1-(1-adamantyl)-1-alkylalkyl
(meth)acrylate. The use of 2-alkyl-2-adamantyl (meth)acrylate as the monomer for
the structural unit is preferable for excellent resolution. Representative examples
of such 2-alkyl-2-adamantyl (meth)acrylate include 2-methyl-2-adamantyl acrylate,
2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl
methacrylate, 2-n-butyl-2-adamantyl acrylate, and the like. Among these, the use
of 2-ethyl-2-adamantyl (meth)acrylate is, in particular, preferable for an excellent
balance of sensitivity and heat resistance.
The resin containing the structural unit derived from p-hydroxystyrene and the
structural unit derived from 2-ethyl-2-adamantyl (meth)acrylate can be prepared,
for example, by the following way: First, p-acetoxystyrene and 2-ethyl-2-adamantyl
(meth)acrylate are copolymerized by a conventional method, and then subjected to
hydrolysis appropriately to convert a part or all of the acetoxy groups into hydroxyl
group, thereby enabling its production.
Copolymerization of hydroxystyrene or acetoxystyrene and 2-ethyl-2-adamantyl
(meth)acrylate, and if necessary, further adding another monomer having an acid
labile group and/or a monomer other than that can be carried out by a conventional
method. For example, a usable method is that a raw material monomer is dissolved
in an appropriate solvent, followed by adding a polymerization initiator therein
to initiate polymerization and continuing the reaction under heating or cooling.
As the solvent, alcohols such as methanol, ethanol, 2-propanol and tert-butanol,
aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as tetrahydrofuran,
1,4-dioxane and the like can be used. As the polymerization initiator, azo compounds
such as 2,2′-azobis(isobutyronitrile) and dimethyl 2,2′azobis(2-methyl
propionate), peroxides such as benzoyl peroxide and tert-butyl peroxide, redox-based
initiators such as hydrogen peroxide/ferrous salt and benzoyl peroxide/dimethylaniline,
alkylated metal compounds such as butyllithium and triethylaluminum, and the like
can be used.
The resin component constituting the present composition essentially contains
the structural unit derived from p-hydroxystyrene and the structural unit represented
by the formula (Ia) or (Ib), other structural units, for example, structural units
derived from styrene, acrylonitrile, methyl methacrylate, methyl acrylate and the
like respectively may also be contained. Further, the resin component may contain
a structural unit having partially hydrogenated benzene ring, or alkylated or alkoxylated
benzene ring as long as alkali solubility is retained.
It is advantageous for the total amount of the structural unit derived from p-hydroxystyrene
and the structural unit represented by the formulae (Ia) and (Ib) to occupy 50
mol % or more of the whole resin. As for the ratio of both structural units, the
molar ratio of the structural unit derived from p-hydroxystyrene to the structural
unit represented by the formulae (Ia) and (Ib) is usually in the range of 99:1
to 60:40, and preferably in the range of 95:5 to 70:30. In addition, the amount
of the structural unit represented by the formulae (Ia) and (Ib) is usually 50
mol % or less based on the whole resin component, and preferably 10 to 45 mol %.
The present composition contains a radiation-sensitive acid generator comprising
a sulfonic acid ester of N-hydroxyimide compound and an onium salt. A combined
use of the sulfonic acid ester of N-hydroxyimide compound and the onium salt in
the present composition is effective in making it possible to achieve high sensitivity
without decreasing resolution and yield an excellent pattern shape as well as edge roughness.
Examples of the sulfonic acid ester of N-hydroxyimide compound include the
compounds represented by the following formula (II):
##STR6##
wherein R
6 represents arylene which may be substituted, alkylene
which may be substituted, or alkenylene which may be substituted, and R
7 represents
alkyl which may be substituted or aryl which may be substituted.
The arylene of R
6 in the formula (II) may be, for example, phenylene,
naphthylene or the like, and the phenylene or naphthylene may be unsubstituted
or substituted. Substituent groups of phenylene and naphthylene include alkyl having
1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, halogen such as fluorine,
chlorine, bromine and iodine, nitro, acetylamino and the like. It is preferable
for the phenylene to be 1,2-phenylene and for the naphthylene to be 1,2-, 2,3-
or 1,8-naphthylene.
The alkylene represented by R
6 may have 1 to 6 carbon atoms and may
be either unsubstituted or substituted. In addition, the alkylene having 2 or more
carbon atoms may be straight chained or branched. Preferable alkylene is, for example,
ethylene, propylene or trimethylene. The substituents of the alkylene include halogen
such as fluorine, chlorine, bromine and iodine, alkoxy having 1 to 4 carbon atoms
and phenyl which is unsubstituted or substituted by a group such as alkyl having
1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, halogen, nitro or acetylamino.
The alkenylene represented by R
6 may have 2 to 4 carbon atoms, be
either unsubstituted or substituted, and be straight chained or branched. Preferable
alkenylene is, for example, vinylene. Substituent groups of the alkenylene include
unsubstituted phenyl and phenyl substituted with a group, for example, alkoxy having
1 to 4 carbon atoms, halogen, nitro or acetylamino.
The alkyl of R
7 in the formula (II) may have, for example, 1 to 12
carbon atoms, and may be either unsubstituted or substituted. In addition, alkyl
having 3 or more carbon atoms may be straight chained, branched or cyclic. Substituents
of the alkyl include halogen such as fluorine, chlorine, bromine and iodine, alkoxy
having 1 to 4 carbon atoms, oxo, and phenyl which is unsubstituted or substituted
with a group such as alkyl having 1 to 4 carbon atoms, halogen, nitro or acetylamino.
The aryl of R
7 may be, for example, phenyl or naphthyl, and the phenyl
and naphthyl may be unsubstituted or substituted. Substituents of the phenyl or
naphthyl include alkyl. having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon
atoms, halogen such as fluorine, chlorine, bromine and iodine, nitro, and acetylamino.
The compounds represented by the formula (II) can be prepared by reacting N-hydroxydicarboxyimide
with alkylsulfonyl chloride or arylsulfonyl chloride under a basic condition according
to the method described by L. Bauer et al., J. Org. Chem. 24, 1293 (1959). The
N-hydroxydicarboxyimide can be synthesized, for example, according to the method
described by G. F. Jaubert, Ber. Dtsch. Chem. 28, 360 (1985), D. E. Ames et al.,
J. Chem. Soc., 3518 (1955), or M. A. Stolberg et al., J. Amer. Chem. Soc., 79,
2615 (1957).
Examples of the N-hydroxyimide compounds include the followings:
- N-(ethylsulfonyloxy)succinimide,
- N-(isopropylsulfonyloxy)succinimide,
- N-(butlysulfonyloxy)succinimide,
- N-(hexylsulfonyloxy)succinimide,
- N-(trifluoromethylsulfonyloxy)succinimide,
- N-(chloromethylsulfonyloxy)succinimide,
- N-(cyclohexylsulfonyloxy)succinimide,
- N-(benzylsulfonyloxy)succinimide,
- N-(phenylsulfonyloxy)succinimide,
- N-(p- or o-tolylsulfonyloxy)succinimide,
- N-(2,5-xylylsulfonyloxy)succinimide,
- N-(4-ethylphenylsulfonyloxy)succinimide,
- N-(2,4,6-trimethylphenylsulfonyloxy)succinimide,
- N-(2,4,6-triisopropylphenylphenylsulfonyloxy)succinimide,
- N-(4-methoxyphenylsulfonyloxy)succinimide,
- N-(4-chlorophenylsulfonyloxy)succinimide,
- N-(2,4,5-trichlorophenylsulfonyloxy)succinimide,
- N-(2- or 4-nitrophenylsulfonyloxy)succinimide,
- N-(4-methoxy-2-nitrophenylsulfonyloxy)succinimide,
- N-(1-naphtylsulfonyloxy)succinimide,
- N-(10-canphorsulfonyloxy)succinimide,
- N-(trifluoromethylsulfonyloxy)succinimide,
- N-(trifluoromethylsulfonyloxy)-5-norbornen-2,3-dicarboxyimide,
- N-(trifluoromethylsulfonyloxy)naphtalimide,
- N-(10-canphorsulfonyloxy)naphtalimide, and the like.
The onium salt in the present composition includes triphenylsulfonium salt represented
by the following formula (IIIa) and diphenyliodonium salt represented by the following
formula (IIIb) respectively:
##STR7##
In the formulae (IIIa) and (IIIb), P
1, P
2, P
3,
P
4 and P
5 each independently represent hydrogen, hydroxyl,
alkyl having 1 to 6 carbon atoms or alkoxy having 1 to 6 carbon atoms, and the
alkyl and alkoxy may be either straight chained or branched when their carbon atoms
are 3 or more. X
- represents a counter ion.
Specific examples of the alkyl having 1 to 6 carbon atoms include methyl,
ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl and the like, and examples
of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, propoxy,
butoxy and the like.
Further, it is preferable that the counter ion X
- of the above
onium salt is the compound represented by the following formula (IVa) or (IVb).
##STR8##
In the formula (IVa), p is an integer of 1 to 8. In the formula (IVb), Q
1,
Q
2, Q
3, Q
4 and Q
5 each independently
represent hydrogen, hydroxyl, alkyl having 1 to 12 carbon atoms which may be branched,
perfluoroalkyl having 1 to 12 carbon atoms which may be branched, alkoxy having
1 to 12 carbon atoms, electron-withdrawing group, or a group represented by the
following formula (V):
wherein Y represents alkylene having 1 to 16 carbon atoms in which —CH
2—
other than that binding to the adjacent —COO— group may be substituted
by —S— or —O—, Z represents hydrogen or alicyclic hydrocarbon
having 3 to 20 carbon atoms.
Examples of the perfluoroalkyl having 1 to 12 carbon atoms includes trifluoromethyl,
perfluorobutyl, perfluorooctyl and the like, examples of the alkyl having 1 to
12 carbon atoms includes methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl,
cyclohexyl, octyl and the like, examples of the alkoxy group having 1 to 12 carbon
atoms includes methoxy, ethoxy, propoxy, butoxy and the like, and examples of the
electron-withdrawing group includes halogen such as fluoro, chloro and bromo, cyano,
nitro, carbonyl, sulfonyl and the like, and preferably nitro among them.
Further, when a plurality of groups represented by the formula (V) are present
in the formula (IVb), they may be the same or different from one another.
Examples of the alkylene having 1 to 16 carbon atoms in the formula (V)
include methylene, ethylene, propan-1,3-diyl, methylethylene, propan-2,2-diyl,
butan-1,4-diyl, 2-methylpropan-1,2-diyl, pentan-1,5-diyl, hexan-1,6-diyl, octan-1,8-diyl,
decan-1,10-diyl, dodecan-1,10-diyl, hexadecan-1,16-diyl and the like.
Examples of the alkylene group having 1 to 16 carbon atoms in which —CH
2—
other than that binding to the adjacent —COO— group is substituted
by —S— or —O— following groups:
Examples of the alicyclic hydrocarbon having 3 to 20 carbon atoms include
following groups:
##STR9##
In the above, preferable groups include cyclohexyl, 2-norbornyl, 1-adamantyl
and 2-adamantyl.
The triphenylsulfonium salt of the formula (IIIa) can be used as it is when it
is commercially available, and also can be produced according to conventional methods.
The methods for producing triphenylsulfonium salt produced may be, for example,
a method reacting corresponding triphenylsulfonium bromide with silver salt of
sulfonic acid having the same structure of anion part of the intended sulfonium
salt; a method reacting corresponding diphenylsulfoxide, aryl compound (i.e. diphenyl
ether, diphenylsufoxide, and the like) and perfluoroalkanesulfonic acid in the
presence of trifluoroacetic anhydride according to the method described in Chem.
Pharm. Bull., Vol. 29, 3753 (1981); a method reacting corresponding aryl Grignard
reagent with thionyl chloride, reacting the product with triorganosilyl halide
to obtain triarylsulfonium halide, and then reacting the triarylsulfonium halide
with silver salt of sulfonic acid having the same structure of anion part of the
intended sulfonate according to the method described in JP-H08-311018-A; and the
like. The sulfonium salt in which P
1, P
2 or P
3 in
the formula (IIIa) is hydroxy, can be produced by reacting triphenylsulfonium salt
having tert-butoxy on its benzene ring with sulfonic acid having the same structure
of anion part of the intended sulfonium salt to eliminate the tert-butyl according
to the method described in JP-H08-311018-A.
The methods for producing diphenyliodonium salt of the formula (IIIb) may be,
for example, a method reacting iodosyl sulfate with corresponding aryl compound,
and then adding thereto corresponding sulfonic acid having the same structure of
anion part of the intended diphenyliodonium salt according to a method described
in J. Am. Chem. Soc., vol. 81, 342 (1959); a method adding iodine and trifluoro
acetic acid to a mixture of acetic anhydride and fuming nitric acid, then reacting
the reaction mixture and corresponding aryl compound, and then adding thereto corresponding
sulfonic acid having the same structure of anion part of the intended diphenyliodonium
salt; a method reacting a mixture of corresponding aryl compound, acetic anhydride
and potassium iodate by adding drop-wise concentrated sulfuric acid thereto, and
then adding thereto corresponding sulfonic acid having the same structure of anion
part of the intended diphenyliodonium salt according to a method described in JP-H09-179302-A;
and the like.
Specific examples of the triphenylsulfonium salt of the formula (IIIa) and
the diphenyliodonium salt of the formula (IIIb) include as follows:
- triphenylsulfonium trifluoromethanesulfonate,
- triphenylsulfonium perfluorobutanesulfonate,
- triphenylsulfonium perfluorooctanesulfonate,
- 4-methylphenyldiphenylsulfonium trifluoromethanesulfonate,
- 4-methylphenyldiphenylsulfonium perfluorobutanesulfonate,
- 4-methylphenyldiphenylsulfonium perfluorooctanesulfonate,
- 4-hydroxyphenyldiphenylsulfonium perfluorobutanesulfonate,
- 4-hydroxyphenyldiphenylsulfonium perfluorooctanesulfonate,
- 4-methoxyphenyldiphenylsulfonium perfluorobutanesulfonate,
- 4-methoxyphenyldiphenylsulfonium perfluorooctanesulfonate,
- tris(4-methylphenyl)sulfonium perfluorobutanesulfonate,
- tris(4-methylphenyl)sulfonium perfluorooctanesulfonate,
- tris(4-methoxyphenyl)sulfonium perfluorobutanesulfonate,
- tris(4-methoxyphenyl)sulfonium perfluorooctanesulfonate,
- 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate,
- 4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate,
- diphenyliodonium trifluoromethanesulfonate,
- diphenyliodonium perfluorobutanesulfonate,
- 4-methoxyphenylphenyliodonium trifluoromethanesulfonate,
- di(4-methoxyphenyl)iodonium perfluorooctanesulfonate,
- di(4-tert-butylphenyl)iodonium trifluoromethanesulfonate,
- di(4-tert-butylphenyl)iodonium perfluorooctanesulfonate,
- triphenylsulfonium benzenesulfonate,
- triphenylsulfonium p-toluenesulfonate,
- triphenylsulfonium triisopropylbenzenesulfonate,
- triphenylsulfonium 2-fluorobenzenesulfonate,
- triphenylsulfonium 4-fluorobenzenesulfonate,
- triphenylsulfonium 2,4-difluorobenzenesulfonate,
- triphenylsulfonium 4-(n-butyl)benzenesulfonate,
- triphenylsulfonium 4-(n-octyl)benzenesulfonate,
- triphenylsulfonium 4-(n-dodecyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium benzenesulfonate,
- 4-methylphenyldiphenylsulfonium p-toluenesulfonate,
- 4-methylphenyldiphenylsulfonium triisopropylbenzenesulfonate,
- 4-methylphenyldiphenylsulfonium 2-fluorobenzenesulfonate,
- 4-methylphenyldiphenylsulfonium 4-fluorobenzenesulfonate,
- 4-methylphenyldiphenylsulfonium 2,4-difluorobenzenesulfonate,
- 4-methylphenyldiphenylsulfonium 4-(n-butyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 2,4,6-triisopropyl-3-nitrobenzenesulfonate,
- 4-methylphenyldiphenylsulfonium 4-(n-octyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium 4-(n-dodecyl)benzenesulfonate,
- tris(4-methylphenyl)sulfonium benzenesulfonate,
- tris(4-methylphenyl)sulfonium p-toluenesulfonate,
- tris(4-methylphenyl)sulfonium triisopropylbenzenesulfonate,
- tris(4-methylphenyl)sulfonium 2-fluorobenzenesulfonate,
- tris(4-methylphenyl)sulfonium 4-fluorobenzenesulfonate,
- tris(4-methylphenyl)sulfonium 2,4-difluorobenzenesulfonate,
- tris(4-methylphenyl)sulfonium 4-(n-butyl)benzenesulfonate,
- tris(4-methylphenyl)sulfonium 4-(n-octyl)benzenesulfonate,
- tris(4-methylphenyl)sulfonium 4-(n-dodecyl)benzenesulfonate,
- 4-hydroxyphenyldiphenylsulfonium benzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium p-toluenesulfonate,
- 4-methoxyphenyldiphenylsulfonium triisopropylbenzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium 2-fluorobenzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium 4-fluorobenzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium 2,4-difluorobenzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium 4-(n-butyl)benzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium 4-(n-octyl)benzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium 4-(n-dodecyl)benzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium benzenesulfonate,
- 4-methoxyphenyldiphenylsulfonium benzenesulfonate,
- tris(4-methoxyphenyl)sulfonium benzenesulfonate,
- tris(4-methoxyphenyl)sulfonium p-toluenesulfonate,
- tris(4-methoxyphenyl)sulfonium triisopropylbenzenesulfonate,
- tris(4-methoxyphenyl)sulfonium 2-fluorobenzenesulfonate,
- tris(4-methoxyphenyl)sulfonium 4-fluorobenzenesulfonate,
- tris(4-methoxyphenyl)sulfonium 2,4-difluorobenzenesulfonate,
- tris(4-methoxyphenyl)sulfonium 4-(n-butyl)benzenesulfonate,
- tris(4-methoxyphenyl)sulfonium 4-(n-octyl)benzenesulfonate,
- tris(4-methoxyphenyl)sulfonium 4-(n-dodecyl)benzenesulfonate,
- triphenylsulfonium 1-(methoxycarbonyl)benzenesulfonate,
- triphenylsulfonium 4-(n-pentyloxycarbonyl)benzenesulfonate,
- triphenylsulfonium 4-(n-octyloxycarbonyl)benzenesulfonate,
- triphenylsulfonium 3,5-bis(methoxycarbonyl)benzenesulfonate,
- triphenylsulfonium 3,5-bis(ethoxycarbonyl)benzenesulfonate,
- triphenylsulfonium 3,5-bis(n-octyloxycarbonyl)benzenesulfonate,
- triphenylsulfonium 3,5-bis(n-hexadecyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(methoxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(n-octyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(n-hexadecyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(cyclopentyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(cyclohexylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(2-norbornylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(1-adamantylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(2-adamantylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium 2,4-dichloro-5-(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium 2,6-dichloro-5-(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3-bromo-6-(cyclohexylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium 2,6-dinitro-4-(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(10-cyclohexyl-3,6-dioxadecyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 4-(10-cyclohexyl-3,6-dithiadecyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,4-bis(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(2-norbornylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(1-adamantylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 3,5-bis(2-adamantylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 2,4,6-tris(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 2,4,6-tris(2-norbornylmethyloxycarbonyl)benzenesulfonate,
- 4-methylphenyldiphenylsulfonium
- 2,4,6-tris(1-adamantylmethyloxycarbonyl)benzenesulfonate,
- diphenyliodonium p-toluenesulfonate,
- di(4-methoxyphenyl)iodonium p-toluenesulfonate,
- di(4-tert-butylphenyl)iodonium benzenesulfonate,
- di(4-tert-butylphenyl)iodonium p-toluenesulfonate,
- di(4-tert-butylphenyl)iodonium triisopropylbenzenesulfonate,
- di(4-tert-butylphenyl)iodonium 2,4,6-triisopropyl-3-nitrobenzenesulfonate,
- di(4-tert-butylphenyl)iodonium 2-fluorobenzenesulfonate,
- di (4-tert-butylphenyl)iodonium 4-fluorobenzenesulfonate,
- di(4-tert-butylphenyl)iodonium 2,4-difluorobenzenesulfonate,
- di(4-tert-butylphenyl)iodonium 4-(n-butyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium 4-(n-octyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium 4-(n-dodecyl)benzenesulfonate,
- diphenyliodonium 4-(n-octyloxycarbonyl)benzenesulfonate,
- diphenyliodonium 4-(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 4-(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 4-(2-norbornylmethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 4-(1-adamantylmethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 4-(2-adamantylmethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 3,5-bis(2-cyclohexylethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 3,5-bis(2-norbornylmethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 3,5-bis(1-adamantylmethyloxycarbonyl)benzenesulfonate,
- di(4-tert-butylphenyl)iodonium
- 3,5-bis(2-adamantylmethyloxycarbonyl)benzenesulfonate.
A basic organic compound may preferably be contained in the present composition,
because performance deterioration due to the deactivation of an acid associated
with leaving after exposure can be reduced. In such case, the basic organic compound
is also called a quencher. Examples of the basic compounds include nitrogen-containing
basic organic compound, such as amines. Specific examples of the nitrogen-containing
basic organic compound include the ones represented by the following formulae:
##STR10##
In the formulae, R
12, R
13 and R
18 each independently
represent hydrogen, alkyl, cycloalkyl or aryl. The alkyl preferably has about 1
to 6 carbon atoms, the cycloalkyl preferably has about 5 to 10 carbon atoms, and
the aryl preferably has about 6 to 10 carbon atoms. Furthermore, at least one hydrogen
on the alkyl, cycloalkyl or aryl may each independently be substituted with hydroxyl,
amino, or alkoxy having 1 to 6 carbon atoms. At least one hydrogen on the amino
group each independently may be substituted with alkyl group having 1 to 4 carbon atoms.
R
14, R
15 and R
16 each independently represent
hydrogen, alkyl cycloalkyl, aryl or alkoxy. The alkyl preferably has about 1 to
6 carbon atoms, the cycloalkyl preferably has about 5 to 10 carbon atoms, the aryl
preferably has about 6 to 10 carbon atoms, and the alkoxy preferably has about
1 to 6 carbon atoms. Furthermore, at least one hydrogen on the alkyl, cycloalkyl,
aryl or alkoxy each independently may be substituted with hydroxyl, amino, or alkoxy
having 1 to 6 carbon atoms. At least one hydrogen on the amino may be substituted
with alkyl having 1 to 4 carbon atoms.
R
17 represents alkyl or cycloalkyl. The alkyl preferably has
about 1 to 6 carbon atoms, and the cycloalkyl preferably has about 5 to 10 carbon
atoms. Furthermore, at least one hydrogen on the alkyl or cycloalkyl may each independently
be substituted with hydroxyl, amino, or alkoxy having 1 to 6 carbon atoms. At least
one hydrogen on the amino may be substituted with alkyl having 1 to 4 carbon atoms.
However, none of R
12, R
13, R
17 and R
18
in the compound represented by the above formula [3] is hydrogen.
A represents alkylene, carbonyl, imino, sulfide or disulfide. The alkylene preferably
has about 2 to 6 carbon atoms.
Moreover, among R
12-R
18, in regard to those which
can be straight-chained or branched, either of these may be permitted.
R
19, R
20 and R
21 each independently
represent hydrogen, alkyl having 1 to 6 carbon atoms, aminoalkyl having 1 to 6
carbon atoms, hydroxyalkyl having 1 to 6 carbon atoms or substituted or unsubstituted
aryl having 6 to 20 carbon atoms, or R
19 and R
20 bond to
form alicyclic hydrocarbon ring together with adjacent carbon atom.
Examples of such compounds include hexylamine, heptylamine, octylamine,
nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, 1-
or 2-naphtylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine,
4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane,
4,4′-diamino-3,3′-diethyldiphenylmethane, dibutylamine, dipentylamine,
dihexylamine, diheptylamine, dibutylamine, dinonylamine, didecylamine, N-methylaniline,
piperidine, diphenylamine, triethylamine, trimethylamine, tripropylamine, tributylamine,
tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine,
methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine,
methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine,
ethyldibutylamine, ethydipentylamine, ethyldihexylamine, ethydiheptylamine, ethyldioctylamine,
ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2-(2-methoxyethoxy)
ethyl]amine, trilsopropanolamine, N,N-dimethylaniline, 2,6-isopropylaniline, imidazole,
pyridine, 4-methylpyridine, 4-methyimidazole, bipyridine, 2,2′-dipyri dylaamine,
di-2-pyridyl ketone, 1,2-di(2-pyridyl)ethane, 1,2-di(4-pyridyl)ethane, 1,3-di(4-pyridyl)propane,
1,2-bis(2-pyridyl)ethylene, 1,2-bis(4-pyridyl)ethylene, 1,2-bis(2-pyridyloxy)ethane,
4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 1,2-bis(4-pyridyl)ethylene,
2,2′-dipicolylamine, 3,3′-dipicolylamine, tetramethylammonium hydroxide,
tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium
hydroxide, tetra-n-octylammonium hydroxide, phenyltrimethylammonium hydroxide,
3-trifluoromethylphenyltrimethylammonium hydroxide, (2-hydroxyethyl)trimethylammonium
hydroxide (so-called "choline"), N-methylpyrrolidone, dimethylimidazole, and the like.
Furthermore, hindered amine compounds having piperidine skeleton as
disclosed in JP-A-H11-52575 can be used as quencher.
The present composition contains a radiation-sensitive acid generator preferably
in a range of 0.3 to 50 parts by weight per 100 parts by weight of resin component.
When a combination of a compound shown by the formula (II) and at least one sulfonium
salt selected from the formula (IIIa) or (IIIb) is used as a radiation-sensitive
acid generator, both compounds are used preferably at a weight ratio of 9:1 to
1:9, more preferably at a weight ratio of 8:2 to 2:8. When a basic compound as
a quencher the compound is contained preferably at a range of 0.001 to 5 parts
by weight, more preferably at a range of 0.01 to 1 part by weight per 100 parts
by weight of a resin in the present composition.
The present composition may contain, as required, small amounts of various additives
such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers,
dyes and the like as long as the effect of the present invention is not prevented.
The present composition is usually in the form of a resist liquid composition
in which the aforementioned ingredients are dissolved in a solvent, and the resist
liquid composition is to be applied onto a substrate such as a silicon wafer by
a conventional process such as spin coating. The solvent used here is sufficient
to dissolve the aforementioned ingredients, have an adequate drying rate, and give
a uniform and smooth coat after evaporation of the solvent and, hence, solvents
generally used in the art can be used. In the present invention, the total solid
content means total content exclusive of solvents.
Examples thereof include glycol ether esters such as ethylcellosolve acetate,
methylcellosolve acetate and propylene glycol monomethyl ether acetate; esters
such as ethyl lactate, butyl lactate, amyl lactate and ethyl pyruvate and the like;
ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone;
cyclic esters such as γ-butyrolactone, and the like. These solvents can be
used each alone or in combination of two or more.
A resist film applied onto the substrate and then dried is subjected to exposure
for patterning, then heat-treated for facilitating a deblocking reaction, and thereafter
developed with an alkali developer. The alkali developer used here may be any one
of various alkaline aqueous solutions used in the art, and generally, an aqueous
solution of tetramethylammonium hydroxide or (2-hydroxyethyl)trimethylammonium
hydroxide (commonly known as "choline") is often used.
It should be construed that embodiments disclosed here are examples in all aspects
and not restrictive. It is intended that the scope of the present invention is
determined not by the above descriptions but by appended Claims, and includes all
variations of the equivalent meanings and ranges to the Claims.
The present invention will be further illustrated by examples. However, the present
invention is not limited to them at all.
In the examples, % and parts showing content and use amount are by weight unless
otherwise stated. Weight-average molecular weight (Mw) and degree of polydispersion
(Mw/Mn) are values measured by gel permeation chromatography using polystyrene
as a standard.
SYNTHETIC EXAMPLE 1
Synthesis of 2-ethyl-2-adamantyl methacrylate/p-acetoxystyrene (20:80) copolymer
Into a flask were added 39.7 g (0.16 mol) of 2-ethyl-2-adamantyl methacrylate,
103.8 g (0.64 mol) of p-acetoxystyrene and 265 g of isopropanol, followed by heating
up to 75° C. under an atmosphere of nitrogen. To this solution was dropped
a solution of 11.05 g (0.048 mol) of dimethyl 2,2′-azobis(2-methylpropionate)
dissolved in 22.11 g of isopropanol. The solution was heated for about 0.3 hour
at 75° C. and further refluxed for about 12 hours. After diluting with acetone,
the reaction mixture was poured into a large amount of methanol to precipitate
the polymerized product, which was separated by filtration. The weight of the obtained
copolymer of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene was 250 g (note:
wet weight of cake containing methanol).
SYNTHETIC EXAMPLE 2
Synthesis of 2-ethyl-2-adamantyl methacrylate/p-hydroxystyrene (20:80) copolymer
Into a flask were added 250 g of the 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene
copolymer (20:80) obtained in Synthetic Example 1, 10.3 g (0.084 mol) of 4-dimethylaminopyridine
and 202 g of methanol, followed by refluxing for 20 hours. After cooling, the reaction
mixture was neutralized with 7.6 g (0.126 mol) of glacial acetic acid, and the
product was precipitated by pouring the reaction mixture into a large amount of
water. After the precipitated polymerized product was separated by filtration and
redissolved in acetone, the procedure of precipitation by pouring polymer solution
into a large amount of water was repeated for a total of 3 times to purify the
polymerized product. The obtained copolymer of 2-ethyl-2-adamantyl methacrylate
and p-hydroxystyrene was 95.9 g. This copolymer had a weight-average molecular
weight of about 8,600 with dispersion of 1.65 (GPC method; on polystyrene basis),
and its copolymerization ratio was determined to be about 20:80 by a nuclear magnetic
resonance (
13C-NMR) analyzer. This resin was referred to as Resin A1.
SYNTHETIC EXAMPLE 3
Synthesis of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene copolymer (30:70)
Into a flask were added 59.6 g (0.24 mol) of 2-ethyl-2-adamantyl methacrylate,
90.8 g (0.56 mol) of p-acetoxystyrene and 279 g of isopropanol, followed by heating
up to 75° C. under an atmosphere of nitrogen. To the solution was dropped
a solution of 11.05 g (0.048 mol) of dimethyl 2,2′azobis(2-methylpropionate)
dissolved in 22.11 g of isopropanol. After the solution was heated for about 0.3
hour at 75 degrees C and further refluxed for about 12 hours, the reaction mixture
was diluted with acetone and poured into a large amount of methanol to precipitate
the polymerized product, which was separated by filtration. The weight of the obtained
copolymer of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene was 250 g (note;
wet weight of cake containing methanol).
SYNTHETIC EXAMPLE 4
Synthesis of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene copolymer (30:70)
Into a flask were added 250 g of the 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene
copolymer (30:70) obtained in Synthetic Example 3, 10.8 g (0.088 mol) of 4-dimethylamino),ridine
and 239 g of methanol, followed by refluxing for 20 hours. After cooling, the reaction
mixture was neutralized with 8.0 g (0.133 mol) of glacial acetic acid, and the
product was precipitated by pouring the reaction mixture into a large amount of
water. After the precipitated polymerized product was redissolved in acetone, the
procedure of precipitation by pouring polymer solution into water was repeated
for a total of 3 times to purify the polymerized product. The obtained crystalline
copolymer of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene was 102.8 g.
This copolymer had a weight-average molecular weight of about 8,200 with dispersion
of 1.68 (GPC method; on polystyrene basis), and its copolymerization ratio was
determined to be about 30:70 by a nuclear magnetic resonance (
13C-NMR)
analyzer. This resin was referred to as Resin A2.
Examples 1 to 6 and Comparative Examples 1 to 4
Each of the following compositions was mixed together, dissolved, and further
filtrated through a fluorine resin filter having pore diameter of 0.2 μm,
to prepare resist solution:
| Resin |
Resin A1 (solid amount) |
5.0 |
parts |
| |
Resin A2 (solid amount) |
5.0 |
parts |
| Acid generator |
Kind and amount shown in Table 1 |
| Quencher |
2,6-Diisopropylaniline |
0.055 |
part |
| Solvent |
Propyleneglycol monomethyl ether |
232.0 |
parts* |
| |
acetate |
| |
Propyleneglycol monomethyl ether |
58.0 |
parts |
| *Solvent amount includes carried from resin solution. |
It should be noted that symbols shown in the "acid generator" column of Table
1 refer to the following compounds, respectively:
- B1: N-(Ethylsulfonyloxy)succinimide
- B1: N-(Butylsulfonyloxy)succinimide
- B1: N-(Isopropylsulfonyloxy)succinimide
- C1: Triphenylsulfonium triisopropylbenzenesulfonate
- C2: Di(4-tert-butylphenyl)iodonium
- 2,4,6-triisopropyl-3-nitorobenzenesulfonate
- C3: 4-Methylphenyldiphenylsulfonium
- 3,5-bis (2-cyclohexylethyloxycarbonyl)benzenesulfonate
- C4: 4-Methylphenyldiphenylsulfonium
- 3,5-bis(1-adamantylmethyloxycarbonyl)benzenesulfonate
Each resist solution was spin-coated on a silicone wafer treated with hexamethyldisilazane
(HMDS), and then pre-baked on a proximity hot plate under a condition of 125°
C. for 60 seconds to form resist film having a thickness of 0.10 μm. The
wafer on which the resist film was formed as described above was exposed to radiation
using an electron beam direct writing system (HL-800D, 50 keV; manufactured by
Hitachi Ltd.). Then, PEB was carried out on a hot plate under a condition of 110°
C. for 60 seconds, and further paddle development was conducted for 60 seconds
using an aqueous solution of 2.38% tetramethylammonium hydroxide. The pattern profile
after the development was observed by a scanning electron microscope, and sensitivity,
resolution and shape were examined. The results are shown in Table 1.
Effective sensitivity: It is expressed as the amount of exposure that the
line pattern (light-shielding layer) and the space pattern (light-transmnitting
layer) become 1:1 after exposure through 0.1 μm line and space pattern.
Resolution: It is expressed as the minimum size of space pattern which
gave the space pattern split by the line pattern at the exposure amount of the
effective sensitivity.
Shape: Shape of cross section of the pattern walls was observed by a scanning
electron microscope, and when the shape is rectangular, judge is O (good), when
the shape is reverse tapered, judge is X (poor).
Smoothness of pattern wall surface: A pattern wall surface of dense line
pattern was observed by a scanning electron microscope, and when line edge roughness
is observed, judge is "X" (poor), and when it is not observed, judge is "O" (good).
| TABLE 1 |
| |
Acid gen- |
|
|
|
Smoothness |
| Example |
erator and |
Effective |
Resolu- |
|
of pattern |
| No. |
its amount |
sensitivity |
tion |
Shape |
profile |
| |
| Example 1 |
B1: 1.0 part |
13.5 |
0.07 |
◯ |
◯ |
| |
C1: 1.0 part |
| Example 2 |
B2: 1.0 part |
7.0 |
0.06 |
◯ |
◯ |
| |
C1: 1.0 part |
| Example 3 |
B3: 1.0 part |
12.8 |
0.07 |
◯ |
◯ |
| |
C1: 1.0 part |
| Example 4 |
B2: 1.0 part |
12.4 |
0.07 |
◯ |
◯ |
| |
C2: 1.0 part |
| Example 5 |
B2: 1.0 part |
9.0 |
0.06 |
◯ |
◯ |
| |
C3: 1.0 part |
| Example 6 |
B2: 1.0 part |
11.4 |
0.07 |
◯ |
◯ |
| |
C4: 1.0 part |
| Comparative |
B1: 1.0 part |
21.0 |
0.10 |
X |
◯ |
| Example 1 |
— |
| Comparative |
— |
31.0 |
0.07 |
X |
X |
| Example 2 |
C1. 1.0
|
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