U.S. patent application number 12/058329 was filed with the patent office on 2008-10-02 for negative resist composition and pattern forming method using the same.
This patent application is currently assigned to FUJIFILM CORPORATION. Invention is credited to Koji Shirakawa, Tadateru Yatsuo.
Application Number | 20080241745 12/058329 |
Document ID | / |
Family ID | 39689049 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080241745 |
Kind Code |
A1 |
Shirakawa; Koji ; et
al. |
October 2, 2008 |
NEGATIVE RESIST COMPOSITION AND PATTERN FORMING METHOD USING THE
SAME
Abstract
A negative resist composition, includes: (A) an alkali-soluble
polymer containing a specific repeating unit as defined in the
specification; (B) a crosslinking agent capable of crosslinking
with the alkali soluble polymer (A) under an action of an acid; (C)
a compound capable of generating an acid upon irradiation with
actinic rays or radiation; (D) a specific quaternary ammonium salt
as defined in the specification; and (E) an organic carboxylic
acid, and a pattern forming method uses the composition.
Inventors: |
Shirakawa; Koji; (Shizuoka,
JP) ; Yatsuo; Tadateru; (Shizuoka, JP) |
Correspondence
Address: |
SUGHRUE-265550
2100 PENNSYLVANIA AVE. NW
WASHINGTON
DC
20037-3213
US
|
Assignee: |
FUJIFILM CORPORATION
Tokyo
JP
|
Family ID: |
39689049 |
Appl. No.: |
12/058329 |
Filed: |
March 28, 2008 |
Current U.S.
Class: |
430/281.1 ;
430/322 |
Current CPC
Class: |
C09D 125/18 20130101;
G03F 7/0382 20130101; G03F 7/11 20130101; H01L 21/32 20130101; Y10S
430/143 20130101; H01L 21/31144 20130101; H01L 21/0274
20130101 |
Class at
Publication: |
430/281.1 ;
430/322 |
International
Class: |
G03F 7/004 20060101
G03F007/004; G03F 7/26 20060101 G03F007/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2007 |
JP |
2007-088557 |
Mar 25, 2008 |
JP |
2008-079338 |
Claims
1. A negative resist composition, comprising: (A) an alkali-soluble
polymer containing a repeating unit represented by formula (1); (B)
a crosslinking agent capable of crosslinking with the alkali
soluble polymer (A) under an action of an acid; (C) a compound
capable of generating an acid upon irradiation with actinic rays or
radiation; (D) a quaternary ammonium salt represented by formula
(2); and (E) an organic carboxylic acid: ##STR00055## wherein A
represents a hydrogen atom, an alkyl group, a halogen atom or a
cyano group; R.sub.1 and R.sub.2 each independently represents a
hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, a
cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group
or an alkylcarbonyloxy group; and n represents an integer of 1 to
3; ##STR00056## wherein R.sub.3 to R.sub.6 each independently
represents an alkyl group, an alkenyl group, an aryl group or an
aralkyl group; B.sup.- represents an OH.sup.- group, a halogen
atom, an R.sub.7--CO.sub.2.sup.- group or an
R.sub.7--SO.sub.3.sup.- group; and R.sub.7 represents an alkyl
group, an alkenyl group, an aryl group or an aralkyl group.
2. The negative resist composition according to claim 1, wherein
the crosslinking agent (B) is a phenol compound having two or more
benzene rings within a molecular thereof and not containing a
nitrogen atom.
3. A pattern forming method, comprising: forming a resist film from
the negative resist composition according to claim 1; and exposing
and developing the resist film.
4. The negative resist composition according to claim 1, wherein
the alkali-soluble polymer (A) further contains at least one
repeating unit selected from the repeating units represented by
formulae (3), (4) and (5): ##STR00057## ##STR00058## represents any
group selected from the following structures: ##STR00059## wherein
A has the same meaning as A in formula (1); X represents a single
bond, a --COO-- group, an --O-- group or a --CON(R.sub.16)-- group;
R.sub.16 represents a hydrogen atom or an alkyl group; R.sub.11 to
R.sub.15 each independently has the same meaning as R.sub.1 in
formula (1); R.sub.101 to R.sub.106 each independently represents a
hydroxy group, a halogen atom, an alkyl group, an alkoxy group, an
alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkenyl
group, an aryl group, an aralkyl group or a carboxy group; and a to
f each independently represents an integer of 0 to 3.
5. The negative resist composition according to claim 1, wherein
the crosslinking agent (B) is a phenol derivative having a
molecular weight of 1,200 or less, containing from 3 to 5 benzene
rings within a molecule thereof, and having two or more
hydroxymethyl groups or alkoxymethyl groups in total, the two or
more hydroxymethyl groups or alkoxymethyl groups being bonded to at
least any one benzene ring in a concentrated manner or distributed
among the benzene rings.
6. The negative resist composition according to claim 1, wherein
the organic carboxylic acid (E) is at least one selected from the
group consisting of a saturated or unsaturated aliphatic carboxylic
acid, an alicyclic carboxylic acid, an oxycarboxylic acid, an
alkoxycarboxylic acid, a ketocarboxylic acid and an aromatic
carboxylic acid.
7. The negative resist composition according to claim 6, wherein
the organic carboxylic acid (E) is at least one selected from the
group consisting of a benzoic acid, a 1-hydroxy-2-naphthoic acid
and a 2-hydroxy-3-naphthoic acid.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a negative resist
composition suitably usable for the ultramicrolithography process
such as production of VLSI or a high-capacity microchip or in other
fabrication processes, and a pattern forming method using the same.
More specifically, the present invention relates to a negative
resist composition capable of forming a high-resolution pattern by
using electron beam or X-ray, and a pattern forming method using
the same. That is, the present invention relates to a negative
resist composition for use in the process using a substrate having
thereon a specific underlying film.
[0003] 2. Description of the Related Art
[0004] In the process of producing a semiconductor device such as
IC and LSI, fine processing by lithography using a photoresist
composition has been conventionally performed. Recently, the
integration degree of an integrated circuit is becoming higher and
formation of an ultrafine pattern in the sub-micron or
quarter-micron region is required. To cope with this requirement,
the exposure wavelength also tends to become shorter, for example,
from g line to i line or further to KrF excimer laser light. At
present, other than the excimer laser light, development of
lithography using electron beam or X-ray is proceeding.
[0005] In particular, the electron beam lithography is positioned
as a next-generation or next-next-generation pattern formation
technique and a negative resist assured of high sensitivity and
high resolution is being demanded.
[0006] Also, the electron beam lithography is widely used for the
preparation of a photomask employed in the semiconductor exposure
because of its high resolution property. The process of preparing a
photomask is as follows. A shielding layer mainly comprising a
shielding material such as chromium is provided on a transparent
substrate such as glass substrate to prepare a shielding substrate,
and a resist layer is formed thereon and selectively exposed to
form a resist pattern on the shielding layer. Subsequently, the
shielding layer in the portion where the pattern is not formed is
etched using the resist pattern as a mask to transfer the pattern
to the shielding layer, whereby a photomask comprising a
transparent substrate having provided thereon a shielding layer in
a predetermined pattern can be obtained.
[0007] In the processing using an electron beam, which is a
different system from the block exposure of light, elevation of
sensitivity is very important for reducing the processing time, but
in the case of a negative resist for use with an electron beam,
when higher sensitivity is pursued, the line edge roughness is
worsened in addition to reduction of the resolution and
deterioration of the pattern profile, and a resist capable of
satisfying these properties all at the same time is strongly
demanded. The line edge roughness as used herein means that the
resist edge at the interface between the pattern and the substrate
irregularly fluctuates in the direction perpendicular to the line
direction due to the resist characteristics and when the pattern is
viewed from right above, the edge gives an uneven appearance. This
unevenness is transferred by the etching step using the resist as a
mask and impairs the dimensional precision. Particularly, in the
ultrafine region of 0.25 .mu.m or less, the line edge roughness is
a very important problem to be solved.
[0008] Also, it is known that when a resist pattern is formed on
the shielding layer used for the preparation of a photomask,
deterioration of the pattern profile is brought about. In
particular, when a negative resist is used, pattern collapse occurs
due to erosion at the interface with the substrate, giving rise to
an issue that the resolving power significantly deteriorates, and
this becomes a problem.
[0009] The high sensitivity is in a trade-off relationship with
high resolution, good pattern profile and good line edge roughness
and it is very important how to satisfy these properties all at the
same time.
[0010] As regards the resist suitable for the electron beam or
X-ray lithography process, a chemical amplification-type resist
utilizing an acid catalytic reaction is mainly used in view of high
sensitivity and in the case of a negative resist, a chemical
amplification-type resist composition mainly comprising an
alkali-soluble resin, a crosslinking agent, an acid generator and
an additive is being effectively used.
[0011] Various studies have been heretofore made to enhance the
performance of the chemical amplification-type negative resist. The
following studies have been made on the additive, particularly, the
ammonium salt-type additive. For example, JP-A-4-51243 discloses a
combination of a tetraalkylammonium salt and a novolak resin,
JP-A-8-110638 discloses a trialkylammonium hydroxide, and
JP-A-11-149159 discloses a combination of a tetraalkylammonium salt
and a polymer having a carboxylic acid in the side chain.
[0012] However, it is impossible by any combination of these
conventionally known compounds to satisfy high sensitivity, high
resolution, good pattern profile, good line edge roughness, and
good in-vacuum PED characteristic in an ultrafine region all at the
same time.
[0013] Also, in JP-A-10-186660, use of an organic carboxylic acid
is studied, but use of a specific resin and a specific ammonium
salt is not described. Furthermore, JP-A-2003-295439 sets forth use
of an ammonium salt but is silent on use of an organic carboxylic
acid. In addition, neither of these patent publications refers to
improving the line edge roughness while giving a good pattern
profile with less erosion, which is the effect of the present
invention.
SUMMARY OF THE INVENTION
[0014] An object of the present invention is to solve the problems
in the technique of enhancing performances at the fine processing
of a semiconductor device or a photomask and provide a negative
resist composition satisfying high sensitivity, high resolution,
good pattern profile, good line edge roughness and good in-vacuum
PED characteristic all at the same time particularly in the fine
processing of a semiconductor or a photomask, where electron beam
or X-ray is used, and a pattern forming method using the
composition.
[0015] As a result of intensive studies, the present inventors have
found that the object of the present invention can be attained by a
negative resist composition using an alkali-soluble resin with a
specific structure, a crosslinking agent, an acid generators an
ammonium salt with a specific structure, and an organic carboxylic
acid.
[0016] That is, the present invention is as follows.
[0017] (1) A negative resist composition, comprising:
[0018] (A) an alkali-soluble polymer containing a repeating unit
represented by formula (1);
[0019] (B) a crosslinking agent capable of crosslinking with the
alkali soluble polymer (A) under an action of an acid;
[0020] (C) a compound Capable of generating an acid upon
irradiation with actinic rays or radiation;
[0021] (D) a quaternary ammonium salt represented by formula (2);
and
[0022] (E) an organic carboxylic acid:
##STR00001##
[0023] wherein A represents a hydrogen atom, an alkyl group, a
halogen atom or a cyano group;
[0024] R.sub.1 and R.sub.2 each independently represents a hydrogen
atom, a halogen atom, an alkyl group, an alkenyl group, a
cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group
or an alkylcarbonyloxy group; and
[0025] n represents an integer of 1 to 3;
##STR00002##
[0026] wherein R.sub.3 to R.sub.6 each independently represents an
alkyl group, an alkenyl group, an aryl group or an aralkyl
group;
[0027] B.sup.- represents an OH.sup.- group, a halogen atom, an
R.sub.7--CO.sub.2.sup.- group or an R.sub.7--SO.sub.3.sup.- group;
and
[0028] R.sub.7 represents an alkyl group, an alkenyl group, an aryl
group or an aralkyl group.
[0029] (2) The negative resist composition as described in
[0030] (1) above,
[0031] wherein the crosslinking agent (B) is a phenol compound
having two or more benzene rings within a molecular thereof and not
containing a nitrogen atom.
[0032] (3) A pattern forming method, comprising:
[0033] forming a resist film from the negative resist composition
as described in (1) or (2) above; and
[0034] exposing and developing the resist film.
[0035] Furthermore, preferred embodiments of the present invention
are set forth below,
[0036] (4) The negative resist composition as described in (1) or
(2) above,
[0037] wherein the alkali-soluble polymer (A) further contains at
least one repeating unit selected from the repeating units
represented by formulae (3), (4) and (5):
##STR00003##
##STR00004##
[0038] represents any group selected from the following
structures:
##STR00005##
[0039] wherein A has the same meaning as A in formula (1);
[0040] X represents a single bond, a --COO-- group, an --O-- group
or a --CON(R.sub.16)-- group;
[0041] R.sub.16 represents a hydrogen atom or an alkyl group;
[0042] R.sub.11 to R.sub.15 each independently has the same meaning
as R.sub.1 in formula (1);
[0043] R.sub.101 to R.sub.106 each independently represents a
hydroxy group, a halogen atom, an alkyl group, an alkoxy group, an
alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkenyl
group, an aryl group, an aralkyl group or a carboxy group; and
[0044] a to f each independently represents an integer of 0 to
3.
[0045] (5) The negative resist composition as described in any of
(1), (2) and (4) above,
[0046] wherein the crosslinking agent (B) is a phenol derivative
having a molecular weight of 1,200 or less, containing from 3 to 5
benzene rings within a molecule thereof, and having two or more
hydroxymethyl groups or alkoxymethyl groups in total, the two or
more hydroxymethyl groups or alkoxymethyl groups being bonded to at
least any one benzene ring in a concentrated manner or distributed
among the benzene rings.
[0047] (6) The negative resist composition as described in any of
(1), (2), (4) and (5) above,
[0048] wherein the organic carboxylic acid (E) is at least one
selected from the group consisting of a saturated or unsaturated
aliphatic carboxylic acid, an alicyclic carboxylic acid, an
oxycarboxylic acid, an alkoxycarboxylic acid, a ketocarboxylic acid
and an aromatic carboxylic acid.
[0049] (7) The negative resist composition as described in (6)
above,
[0050] wherein the organic carboxylic acid (E) is at least one
selected from the group consisting of a benzoic acid, a
1-hydroxy-2-naphthoic acid and a 2-hydroxy-3-naphthoic acid.
DETAILED DESCRIPTION OF THE INVENTION
[0051] The negative resist composition of the present invention is
described in detail below.
[0052] Incidentally, when a group (atomic group) is denoted without
specifying whether substituted or unsubstituted, the group includes
both a group having no substituent and a group having a
substituent. For example, an "alkyl group" includes not only an
alkyl group having no substituent (unsubstituted alkyl group) but
also an alkyl group having a substituent (substituted alkyl
group).
[1] (A) Alkali-Soluble Polymer
[0053] The alkali-soluble polymer for use in the present invention
contains a repeating unit represented by formula (1) as an
essential component.
[0054] In formula (1), the alkyl group as A is preferably an alkyl
group having a carbon number of 1 to 3. Examples of the halogen
atom as A include Cl, Br and F.
[0055] A is preferably a hydrogen atom or an alkyl group having a
carbon number of 1 to 3 (e.g., methyl, ethyl), more preferably a
hydrogen atom or a methyl group.
[0056] Examples of the halogen atom as R.sub.1 and R.sub.2 include
Cl, Br, F and I.
[0057] The alkyl group, alkenyl group, cycloalkyl group, aryl
group, aralkyl group, alkoxy group, alkylcarbonyloxy group or
alkylsulfonyloxy group as R.sub.1 and R.sub.2 may have a
substituent. Also, R.sub.1 and R.sub.2 may form a ring in
cooperation.
[0058] R.sub.1 and R.sub.2 each is independently, preferably a
linear or branched alkyl group having a carbon number of 1 to 8,
which may have a substituent, an alkenyl group having a carbon
number of 1 to 8, which may have a substituent, a cycloalkyl group
having a carbon number of 5 to 10, which may have a substituent, an
aryl group having a carbon number of 6 to 15, which may have a
substituent, an aralkyl group having a carbon number of 7 to 16,
which may have a substituent, an alkoxy group having a carbon
number of 1 to 8, which may have a substituent, or an
alkylcarbonyloxy group having a carbon number of 1 to 8, which may
have a substituent.
[0059] Examples of the substituent include an alkyl group (e.g.,
methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, hexyl), an
aryl group (e.g., phenyl, naphthyl), an aralkyl group, a hydroxyl
group, an alkoxy group (e.g., methoxy, ethoxy, butoxy, octyloxy,
dodecyloxy), an acyl group (e.g., acetyl, propanoyl, benzoyl) and
an oxo group.
[0060] R.sub.1 and R.sub.2 each is independently, more preferably a
hydrogen atom, a halogen atom, an alkyl group having a carbon
number of 1 to 4, which may have a substituent, an alkoxy group
having a carbon number of 1 to 4, which may have a substituent, or
an alkylcarbonyloxy group having a carbon number of 1 to 4, which
may have a substituent, still more preferably a hydrogen atom, a
chlorine atom, a bromine atom, an iodine atom, an alkyl group
having a carbon number of 1 to 3 (e.g., methyl, ethyl, propyl,
isopropyl), or an alkoxy group having a carbon number of 1 to 3
(e.g., methoxy, ethoxy, propyloxy, isopropyloxy).
[0061] The polymer as the component (A) for use in the present
invention may have at least one repeating unit represented by
formulae (3) to (5), together with the repeating unit represented
by formula (1).
[0062] In formulae (3) to (5), A has the same meaning as A in
formula (1), X represents a single bond, a --COO-- group, a --O--
group, or a --CON(R.sub.16)-- group, R.sub.16 represents a hydrogen
atom or an alkyl group having a carbon number of 1 to 3 (e.g.,
methyl, ethyl, propyl). X is preferably a single bond, --COO--, or
--CON(R.sub.16), more preferably a --COO-- group.
[0063] R.sub.11 to R.sub.15 each independently has the same meaning
as R.sub.1 in formula (1).
[0064] R.sub.101 to R.sub.106 each independently represents a
hydroxy group, a halogen atom (Cl, Br, F, I), a linear or branched
alkyl group having a carbon number of 1 to 8, which may have a
substituent, a linear or branched alkoxy group having a carbon
number of 1 to 8, a linear or branched alkylcarbonyloxy group
having a carbon number of 1 to 8, which may have a substituent, a
linear or branched alkylsulfonyloxy group having a carbon number of
1 to 8, which may have a substituent, an alkenyl group having a
carbon number of 1 to 8, which may have a substituent, an aryl
group having a carbon number of 7 to 15, which may have a
substituent, an aralkyl group having a carbon number of 7 to 16,
which may have a substituent, or a carboxy group.
[0065] Examples of the substituent thereof are the same as those of
the substituent of R.sub.1 in formula (1).
[0066] R.sub.101 to R.sub.106 each is independently, preferably a
hydrogen atom, a halogen atom, an alkyl group having a carbon
number of 1 to 4, which may have a substituent, an alkoxy group
having a carbon number of 1 to 4, which may have a substituent, or
an alkylcarbonyloxy group having a carbon number of 1 to 4, which
may have a substituent, more preferably a hydrogen atom, a chlorine
atom, a bromine atom, an iodine atom, an alkyl group having a
carbon number of 1 to 3 (e.g., methyl, ethyl, propyl, isopropyl),
an alkoxy group having a carbon number of 1 to 3 (e.g., methoxy,
ethoxy, propyloxy, isopropyloxy), or an alkylcarbonyloxy group
having a carbon number of 1 to 3 (e.g., acetyl, propionyl).
[0067] a to f each independently represents an integer of 0 to
3.
[0068] The polymer as the component (A) for use in the present
invention may be any of a resin having only one repeating unit
represented by formula (1), a resin having two or more repeating
units each represented by formula (1), and a resin having a
repeating unit represented by formula (1) and at least one
repeating unit selected from the repeating units represented by
formulae (3) to (5), and other polymerizable monomers capable of
controlling the film-forming property or alkali solubility may be
also polymerized therein.
[0069] Example of such a polymerizable monomer include, but are not
limited to, styrene, an alkyl-substituted styrene, an
alkoxy-substituted styrene, an O-alkylated styrene, an O-acylated
styrene, a hydrogenated hydroxystyrene, maleic anhydride, an
acrylic acid derivative (e.g., acrylic acid, acrylic acid ester), a
methacrylic acid derivative (e.g., methacrylic acid, methacrylic
acid ester), an N-substituted maleimide, acrylonitrile and
methacrylonitrile.
[0070] The content of the repeating unit represented by formula (1)
in the polymer as the component (A) for use in the present
invention is generally from 50 to 100 mol %, preferably from 70 to
100 mol %.
[0071] In the polymer as the component (A), the ratio between the
repeating unit represented by formula (1) and the repeating unit(s)
represented by formulae (3) to (5) is, in terms of the molar ratio,
preferably from 100/0 to 50/50, more preferably from 100/0 to
60/40, still more preferably from 100/0 to 70/30.
[0072] The molecular weight of the polymer as the component (A) is,
in terms of the weight average molecular weight, preferably from
1,000 to 200,000, more preferably from 2,000 to 50,000.
[0073] The molecular weight distribution (Mw/Mn) of the polymer as
the component (A) is preferably from 1.0 to 2.0, more preferably
from 1.0 to 1.35.
[0074] The amount added of the polymer as the component (A) is from
30 to 95 mass %, preferably from 40 to 90 mass %, more preferably
from 50 to 80 mass %, based on the entire solid content of the
composition. (In this specification, mass ratio is equal to weight
ratio.)
[0075] Here, the molecular weight and molecular weight distribution
of the polymer are defined as a polystyrene-reduced value by the
GPC measurement.
[0076] The polymer as the component (A) can be synthesized by a
known radical polymerization method or anionic polymerization
method. For example, in the radical polymerization method, the
vinyl monomer is dissolved in an appropriate organic solvent, and
the reaction is allowed to proceed at room temperature or under
heating by using a peroxide (e.g., benzoyl peroxide), a nitrile
compound (e.g., azobisisobutyronitrile) or a redox compound (e.g.,
cumene hydroperoxide-ferrous salt) as the initiator, whereby the
polymer can be obtained. In the anionic polymerization method, the
vinyl monomer is dissolved in an appropriate organic solvent, and
the reaction is allowed to proceed usually under cooling by using a
metal compound (e.g., butyllithium) as the initiator, whereby the
polymer can be obtained.
[0077] Specific examples of the alkali-soluble polymer as the
component (A) for use in the present invention are set forth below,
but the present invention is not limited thereto.
##STR00006## ##STR00007## ##STR00008## ##STR00009## ##STR00010##
##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015##
##STR00016## ##STR00017## ##STR00018## ##STR00019## ##STR00020##
##STR00021## ##STR00022## ##STR00023##
[0078] In specific examples above, n represents a positive integer,
and x, y and z represent the molar ratio of the composition. In the
case of a resin comprising two components, the molar ratio is x=10
to 95 and y=5 to 90, preferably x=40 to 90 and y=10 to 60, and in
the case of a resin comprising three components, the molar ratio is
x=10 to 90, y=5 to 85 and z=5 to 85, preferably x=40 to 80, y=10 to
50 and z=10 to 50.
[0079] One of these polymers may be used alone, or two or more
thereof may be mixed and used,
[2] Acid Cross-Linking Agent (Component (B))
[0080] In the present invention, a compound capable of crosslinking
under the action of an acid (hereinafter sometimes referred to as
an "acid crosslinking agent" or simply as a "crosslinking agent")
is used together with the alkali-soluble polymer. A known acid
crosslinking agent can be effectively used here.
[0081] The acid crosslinking agent is preferably a compound or
resin having two or more hydroxymethyl groups, alkoxy-methyl
groups, acyloxymethyl groups or alkoxymethyl ether groups, or an
epoxy compound.
[0082] More preferred examples thereof include an alkoxymethylated
or acyloxymethylated melamine compound or resin, an
alkoxymethylated or acyloxymethylated urea compound or resin, a
hydroxymethylated or alkoxymethylated phenol compound or resin, and
an alkoxymethyl-etherified phenol compound or resin.
[0083] The component (B) is still more preferably a phenol
derivative having a molecular weight of 1,200 or less, containing
from 3 to 5 benzene rings within the molecule, and having two or
more hydroxymethyl groups or alkoxymethyl groups in total, where
the hydroxymethyl groups or alkoxymethyl groups are bonded in a
concentrated manner to at least any one benzene ring or distributed
among the benzene rings. By virtue of using such a phenol
derivative, the effects of the present invention are more
remarkably brought out.
[0084] The alkoxymethyl group bonded to the benzene ring is
preferably an alkoxymethyl group having a carbon number of 6 or
less, specifically, a methoxymethyl group, an ethoxymethyl group,
an n-propoxymethyl group, an i-propoxymethyl group, an
n-butoxymethyl group, an i-butoxymethyl group, a sec-butoxymethyl
group, or a tert-butoxymethyl group. An alkoxy-substituted alkoxy
group such as 2-methoxyethoxy group and 2-methoxy-1-propyl group is
also preferred.
[0085] The crosslinking agent (B) is preferably a phenol compound
having two or more benzene rings within the molecule and containing
no nitrogen atom.
[0086] Out of these phenol derivatives, particularly preferred
compounds are set forth below.
##STR00024## ##STR00025## ##STR00026##
(wherein L.sup.1 to L.sup.8 may be the same or different and each
represents a hydroxymethyl group, a methoxymethyl group or an
ethoxymethyl group).
[0087] The phenol derivative having a hydroxymethyl group can be
obtained by reacting a corresponding phenol compound having no
hydroxymethyl group (a compound where in the formulae above,
L.sup.1 to L.sup.8 each is a hydrogen atom) with formaldehyde in
the presence of a base catalyst. At this time, in order to prevent
resinification or gelling, the reaction is preferably performed at
a temperature of 60.degree. C. or less. Specifically, this phenol
derivative can be synthesized by the method described, for example,
in JP-A-6-282067 and JP-A-7-64285.
[0088] The phenol derivative having an alkoxymethyl group can be
obtained by reacting a corresponding phenol derivative having a
hydroxymethyl group with an alcohol in the presence of an acid
catalyst. At this time, in order to prevent resinification or
gelling, the reaction is preferably performed at a temperature of
100.degree. C. or less. Specifically, this phenol derivative can be
synthesized by the method described, for example, in
EP-A-632003.
[0089] The thus-synthesized phenol derivative having a
hydroxymethyl group or an alkoxymethyl group is preferred in view
of stability during storage, but a phenol derivative having an
alkoxymethyl group is particularly preferred in view of stability
during storage.
[0090] One of these phenol derivatives having two or more
hydroxymethyl groups or alkoxymethyl groups in total bonded in a
concentrated manner to at least any one benzene ring or distributed
among the benzene rings may be used alone, or two or more thereof
may be used in combination.
[0091] Preferred examples of the crosslinking agent further include
(i) a compound having an N-hydroxymethyl group, an N-alkoxymethyl
group or an N-acyloxymethyl group, and (ii) an epoxy group, which
are described below.
[0092] Examples of the (i) compound having an N-hydroxymethyl
group, an N-alkoxymethyl group or an N-acyloxymethyl group include
monomers, oligomer-melamine-formaldehyde condensates and
urea-formaldehyde condensates disclosed in EP-A-0133216 and West
German Patent Nos. 3,634,671 and 3,711,264, and alkoxy-substituted
compounds and benzoguanamine-formaldehyde condensates disclosed in
EP-A-0212482.
[0093] More preferred examples include a melamine-formaldehyde
derivative having at least two free N-hydroxymethyl groups,
N-alkoxymethyl groups or N-acyloxymethyl groups, with an
N-alkoxymethyl derivative being still more preferred.
[0094] The (ii) epoxy compound includes a monomer-, dimer-,
oligomer- or polymer-form epoxy compound containing one or more
epoxy groups. Examples thereof include a reaction product of
bisphenol A and epichlorohydrin, and a reaction product of low
molecular weight phenol-formaldehyde resin and epichlorohydrin.
Other examples include epoxy resins described and used in U.S. Pat.
No. 4,026,705 and British Patent 1,539,192.
[0095] The crosslinking agent is preferably added in an amount of 3
to 65 mass %, more preferably from 5 to 50 mass %. When the amount
of the crosslinking agent added is from 3 to 65 mass %, reduction
in the residual film ratio and resolving power can be prevented and
at the same time, good stability of the resist solution can be
maintained during storage.
[0096] In the present invention, one crosslinking agent may be used
alone, or two or more kinds of crosslinking agents may be used in
combination.
[0097] For example, in the case of using other crosslinking agents
such as (i) and (ii) above in addition to the phenol derivative,
the ratio between the phenol derivative and the other crosslinking
agent is, in terms of the molar ratio, from 100/0 to 20/80,
preferably from 90/10 to 40/60, more preferably from 80/20 to
50/50.
[3] Compound Capable of Generating an Acid Upon Irradiation with
Actinic Rays or Radiation (Component (C))
[0098] The negative resist composition of the present invention
comprises a compound capable of generating an acid upon irradiation
with actinic rays or radiation (hereinafter sometimes referred to
as an "acid generator").
[0099] The acid generator which can be used may be appropriately
selected from a photoinitiator for photo-cationic polymerization, a
photoinitiator for photoradical polymerization, a photo-decoloring
agent for coloring matters, a photo-discoloring agent, a compound
known to generate an acid upon irradiation with actinic rays or
radiation and used for microresist or the like, and a mixture
thereof.
[0100] Examples thereof include a diazonium salt, a phosphonium
salt, a sulfonium salt, an iodonium salt, imidosulfonate, oxime
sulfonate, diazodisulfone, disulfone and o-nitrobenzyl
sulfonate.
[0101] Also, a compound where a group or compound capable of
generating an acid upon irradiation with actinic rays or radiation
is introduced into the main or side chain of a polymer, such as
compounds described in U.S. Pat. No. 3,849,137, German Patent
3,914,407, JP-A-63-26653, JP-A-55-164824, JP-A-62-69263,
JP-A-63-146038, JP-A-63-163452, JP-A-62-153853 and JP-A-63-146029,
may be used.
[0102] Furthermore, compounds capable of generating an acid by the
effect of light described, for example, in U.S. Pat. No. 3,779,778
and European Patent 126,712 may also be used.
[0103] Out of the compounds capable of decomposing upon irradiation
with actinic rays or radiation to generate an acid, the compounds
represented by the following formulae (ZI), (ZII) and (ZIII) are
preferred.
##STR00027##
[0104] In formula (ZI), R.sub.201, R.sub.202 and R.sub.203 each
independently represents an organic group.
[0105] X.sup.- represents a non-nucleophilic anion, and preferred
examples thereof include sulfonate anion, carboxylate anion,
bis(alkylsulfonyl)amide anion, tris(alkylsulfonyl)methide anion,
BF.sub.4.sup.-, PF.sub.6.sup.- and SbF.sub.6.sup.-. The anion is
preferably an organic anion containing a carbon atom.
[0106] The preferred organic anion includes organic anions
represented by the following formulae (AN1) to (AN4):
##STR00028##
[0107] In formulae (AN1) and (AN2), Rc.sub.1 represents an organic
group.
[0108] The organic group in Rc.sub.1 includes an organic group
having a carbon number of 1 to 30 and is preferably an alkyl or
aryl group which may be substituted, or a group where a plurality
of such groups are connected through a single bond or a linking
group such as --O--, --CO.sub.2--, --S--, --SO.sub.3-- and
--SO.sub.2N(Rd.sub.1)-.
[0109] Rd.sub.1 represents a hydrogen atom or an alkyl group and
may form a ring structure together with the alkyl or aryl group to
which Rd.sub.1 is bonded.
[0110] The organic group of Rc.sub.1 is more preferably an alkyl
group substituted by a fluorine atom or a fluoroalkyl group at the
1-position, or a phenyl group substituted by a fluorine atom or a
fluoroalkyl group. By virtue of having a fluorine atom or a
fluoroalkyl group, the acidity of the acid generated upon
irradiation with light increases and the sensitivity is enhanced.
When Rc.sub.1 has 5 or more carbon atoms, at least one carbon atom
is preferably such that a part of hydrogen atoms remain without
replacing all hydrogen atoms by a fluorine atom, and more
preferably such that the number of hydrogen atoms is larger than
the number of fluorine atoms. The absence of a perfluoroalkyl group
having a carbon number of 5 or more enables reduction in the
toxicity to ecology.
[0111] The most preferred embodiment of Rc.sub.1 is a group
represented by the following formula.
##STR00029##
[0112] In the formula, Rc.sub.6 represents a perfluoroalkylene
group having a carbon number of 4 or less, preferably from 2 to 4,
more preferably 2 or 3, or a phenylene group substituted by from 1
to 4 fluorine atoms and/or from 1 to 3 fluoroalkyl groups.
[0113] Ax represents a single bond or a divalent linking group
(preferably --O--, --CO.sub.2--, --S--, --SO.sub.3-- or
--SO.sub.2N(Rd.sub.1)-). Rd.sub.1 represents a hydrogen atom or an
alkyl group and may combine with Rc.sub.7 to form a ring
structure.
[0114] Rc.sub.7 represents a hydrogen atom, a fluorine atom, a
linear or branched alkyl group which may be substituted, a
monocyclic or polycyclic cycloalkyl group which may be substituted,
or an aryl group which may be substituted. The alkyl group,
cycloalkyl group and aryl group, which each may be substituted,
preferably contain no fluorine atom as the substituent.
[0115] In formulae (AN3) and (AN4), Rc.sub.3, Rc.sub.4 and Rc.sub.5
each independently represents an organic group.
[0116] The preferred organic groups for Rc.sub.3, Rc.sub.4 and
Rc.sub.5 in formulae (AN3) and (AN4) are the same as the preferred
organic groups in Rc.sub.1.
[0117] Rc.sub.3 and Rc.sub.4 may combine to form a ring.
[0118] The group formed by combining Rc.sub.3 and Rc.sub.4 includes
an alkylene group and an arylene group and is preferably a
perfluoroalkylene group having a carbon number of 2 to 4. When
Rc.sub.3 and Rc.sub.4 combine to form a ring, the acidity of the
acid generated upon irradiation with light increases and this is
preferred because the sensitivity is enhanced.
[0119] The carbon number of the organic group as R.sub.201,
R.sub.202 and R.sub.203 in formula (ZI) is generally from 1 to 30,
preferably from 1 to 20.
[0120] Two members out of R.sub.201 to R.sub.203 may combine to
form a ring structure, and the ring may contain an oxygen atom, a
sulfur atom, an ester bond, an amide bond or a carbonyl group.
[0121] Examples of the group formed by combining two members out of
R.sub.201, to R.sub.203 include an alkylene group (e.g., butylene,
pentylene).
[0122] Specific examples of the organic group as R.sub.201,
R.sub.202 and R.sub.203 include corresponding groups in the
compounds (ZI-1), (ZI-2) and (ZI-3) which are described later.
[0123] The compound may be a compound having a plurality of
structures represented by formula (ZI). For example, the compound
may be a compound having a structure where at least one of
R.sub.201 to R.sub.203 in a compound represented by formula (ZI) is
bonded to at least one of R.sub.201 to R.sub.203 in another
compound represented by formula (ZI).
[0124] The component (ZI) is more preferably a compound (ZI-1),
(ZI-2) or (ZI-3) described below.
[0125] The compound (ZI-1) is an arylsulfonium compound where at
least one of R.sub.201 to R.sub.203 in formula (ZI) is an aryl
group, that is, a compound having an arylsulfonium as the
cation.
[0126] In the arylsulfonium compound, R.sub.201 to R.sub.203 all
may be an aryl group or a part of R.sub.201 to R.sub.203 may be an
aryl group with the remaining being an alkyl group or a cycloalkyl
group.
[0127] Examples of the arylsulfonium compound include a
triarylsulfonium compound, a diarylalkylsulfonium compound, an
aryldialkylsulfonium compound, a diarylcycloalkylsulfonium
compound, and an aryldicycloalkylsulfonium compound.
[0128] The aryl group in the arylsulfonium compound is preferably
an aryl group such as phenyl group and naphthyl group, or a
heteroaryl group such as indole residue and pyrrole residue, more
preferably a phenyl group or an indole residue. In the case where
the arylsulfonium compound has two or more aryl groups, these two
or more aryl groups may be the same or different.
[0129] The alkyl group which is present, if desired, in the
arylsulfonium compound is preferably a linear or branched alkyl
group having a carbon number of 1 to 15, and examples thereof
include a methyl group, an ethyl group, a propyl group, an n-butyl
group, a sec-butyl group and a tert-butyl group.
[0130] The cycloalkyl group which is present, if desired, in the
arylsulfonium compound is preferably a cycloalkyl group having a
carbon number of 3 to 15, and examples thereof include a
cyclopropyl group, a cyclobutyl group and a cyclohexyl group.
[0131] The aryl group, alkyl group and cycloalkyl group of
R.sub.201 to R.sub.203 each may have, as the substituent, an alkyl
group (for example, an alkyl group having a carbon number of 1 to
15), a cycloalkyl group (for example, a cycloalkyl group having a
carbon number of 3 to 15), an aryl group (for example, an aryl
group having a carbon number of 6 to 14), an alkoxy group (for
example, an alkoxy group having a carbon number of 1 to 15), a
halogen atom, a hydroxyl group or a phenylthio group. The
substituent is preferably a linear or branched alkyl group having a
carbon number of 1 to 12, a cycloalkyl group having a carbon number
of 3 to 12, or a linear, branched or cyclic alkoxy group having a
carbon number of 1 to 12, more preferably an alkyl group having a
carbon number of 1 to 4 or an alkoxy group having a carbon number
of 1 to 4. The substituent may be substituted to any one of three
members R.sub.201 to R.sub.203 or may be substituted to all of
these three members. In the case where R.sub.201 to R.sub.203 are
an aryl group, the substituent is preferably substituted at the
p-position of the aryl group.
[0132] The compound (ZI-2) is described below.
[0133] The compound (ZI-2) is a compound where R.sub.201 to
R.sub.203 in formula (ZI) each independently represents an aromatic
ring-tree organic group. The aromatic ring as used herein includes
an aromatic ring containing a heteroatom.
[0134] The aromatic ring-free organic group as R.sub.201 to
R.sub.203 generally has a carbon number of 1 to 30, preferably from
1 to 20.
[0135] R.sub.201 to R.sub.203 each is independently preferably an
alkyl group, a cycloalkyl group, an allyl group or a vinyl group,
more preferably a linear, branched or cyclic 2-oxoalkyl group or an
alkoxycarbonylmethyl group, still more preferably a linear or
branched 2-oxoalkyl group.
[0136] The alkyl group as R.sub.201 to R.sub.203 may be either
linear or branched and is preferably a linear or branched alkyl
group preferably having a carbon number of 1 to 10 (e.g., methyl,
ethyl, propyl, butyl, pentyl). The alkyl group as R.sub.201 to
R.sub.203 is more preferably a linear or branched 2-oxoalkyl group
or an alkoxycarbonylmethyl group.
[0137] The cycloalkyl group as R.sub.201 to R.sub.203 is preferably
a cycloalkyl group having a carbon number of 3 to 10 (e.g.,
cyclopentyl, cyclohexyl, norbornyl).
[0138] The cycloalkyl group as R.sub.201 to R.sub.203 is more
preferably a cyclic 2-oxoalkyl group.
[0139] The 2-oxoalkyl group as R.sub.201 to R.sub.203 may be
linear, branched or cyclic and is preferably a group having
>C.dbd.O at the 2-position of the above-described alkyl or
cycloalkyl group.
[0140] The alkoxy group in the alkoxycarbonylmethyl group as
R.sub.201 to R.sub.203 is preferably an alkoxy group preferably
having a carbon number of 1 to 5 (e.g., methoxy, ethoxy, propoxy,
butoxy, pentoxy).
[0141] R.sub.201 to R.sub.203 each may be further substituted by a
halogen atom, an alkoxy group (for example, an alkoxy group having
a carbon number of 1 to 5), a hydroxyl group, a cyano group or a
nitro group.
[0142] The compound (ZI-3) is a compound represented by the
following formula (ZI-3), and this is a compound having a
phenacylsulfonium salt structure.
##STR00030##
[0143] In formula (ZI-3), R.sub.1c to R.sub.5c each independently
represents a hydrogen atom, an alkyl group, a cycloalkyl group, an
alkoxy group or a halogen atom.
[0144] R.sub.6c and R.sub.7c each independently represents a
hydrogen atom, an alkyl group or a cycloalkyl group.
[0145] R.sub.x and R.sub.y each independently represents an alkyl
group, a cycloalkyl group, an allyl group or a vinyl group.
[0146] Any two or more members out of R.sub.1c to R.sub.7c or a
pair of R.sub.x and R.sub.y may combine with each other to form a
ring structure, and the ring structure may contain an oxygen atom,
a sulfur atom, an ester bond or an amide bond. Examples of the
group formed by combining any two or more members out of R.sub.1c
to R.sub.7c or a pair of R.sub.x and R.sub.y include a butylene
group and a pentylene group.
[0147] X.sup.- represents a non-nucleophilic anion, and examples
thereof are the same as those of the non-nucleophilic anion of
X.sup.- in formula (ZI).
[0148] The alkyl group as R.sub.1c to R.sub.7c may be linear or
branched and is, for example, an alkyl group having a carbon number
of 1 to 20, preferably a linear or branched alkyl group having a
carbon number of 1 to 12 (for example, a methyl group, an ethyl
group, a linear or branched propyl group, a linear or branched
butyl group, or a linear or branched pentyl group).
[0149] The cycloalkyl group as R.sub.1c to R.sub.7c is preferably a
cycloalkyl group having a carbon number of 3 to 8 (e.g.,
cyclopentyl, cyclohexyl).
[0150] The alkoxy group as R.sub.1c to R.sub.5c may be linear,
branched or cyclic and is, for example, an alkoxy group having a
carbon number of 1 to 10, preferably a linear or branched alkoxy
group having a carbon number of 1 to 5 (for example, a methoxy
group, an ethoxy group, a linear or branched propoxy group, a
linear or branched butoxy group, or a linear or branched pentoxy
group), or a cyclic alkoxy group having a carbon number of 3 to 8
(e.g., cyclopentyloxy, cyclohexyloxy).
[0151] A compound where any one of R.sub.1c to R.sub.5c is a linear
or branched alkyl group, a cycloalkyl group, or a linear, branched
or cyclic alkoxy group is preferred, and a compound where the sum
of carbon numbers of R.sub.1c to R.sub.5c is from 2 to 15 is more
preferred. By virtue of this construction, the solvent solubility
is more enhanced and generation of particles during storage is
suppressed.
[0152] The alkyl group as R.sub.x and R.sub.y is the same as the
alkyl group of R.sub.1c to R.sub.7c. The alkyl group as R.sub.x and
R.sub.y is preferably a linear or branched 2-oxoalkyl group or an
alkoxycarbonylmethyl group.
[0153] The linear, branched or cyclic 2-oxoalkyl group includes a
group having >C.dbd.O at the 2-position of the alkyl group or
cycloalkyl group as R.sub.1c to R.sub.7c.
[0154] The alkoxy group in the alkoxycarbonylmethyl group is the
same as the alkoxy group of R.sub.1c to R.sub.5c.
[0155] R.sub.x and R.sub.y each is preferably an alkyl group having
a carbon number of 4 or more, more preferably 6 or more, still more
preferably 8 or more.
[0156] In formulae (ZII) and (ZIII), R.sub.204 to R.sub.207 each
independently represents an aryl group which may have a
substituent, an alkyl group which may have a substituent, or a
cycloalkyl group which may have a substituent.
[0157] The aryl group of R.sub.204 to R.sub.207 is preferably a
phenyl group or a naphthyl group, more preferably a phenyl
group.
[0158] The alkyl group of R.sub.204 to R.sub.207 may be linear or
branched and is preferably a linear or branched alkyl group having
a carbon number of 1 to 10 (e.g., methyl, ethyl, propyl, butyl,
pentyl).
[0159] The cycloalkyl group of R.sub.204 to R.sub.207 is preferably
a cycloalkyl group having a carbon number of 3 to 10 (e.g.,
cyclopentyl, cyclohexyl, norbornyl).
[0160] Examples of the substituent which R.sub.204 to R.sub.207
each may have include an alkyl group (for example, an alkyl group
having a carbon number of 1 to 15), a cycloalkyl group (for
example, a cycloalkyl group having a carbon number of 3 to 15), an
aryl group (for example, an aryl group having a carbon number of 6
to 15), an alkoxy group (for example, an alkoxy group having a
carbon number of 1 to 15), a halogen atom, a hydroxyl group and a
phenylthio group.
[0161] X.sup.- represents a non-nucleophilic anion and is the same
as the non-nucleophilic anion of X.sup.- in formula (ZI).
[0162] Out of the compounds capable of generating an acid upon
irradiation with actinic rays or radiation, preferred compounds
further include the compounds represented by the following formulae
(ZIV), (ZV) and (ZVI):
##STR00031##
[0163] In formulae (ZIV) to (ZVI), Ar.sub.3 and Ar.sub.4 each
independently represents a substituted or unsubstituted aryl
group.
[0164] R.sub.208 represents a substituted or unsubstituted alkyl
group, a substituted or unsubstituted cycloalkyl group, or a
substituted or unsubstituted aryl group.
[0165] R.sub.209 and R.sub.210 each represents a substituted or
unsubstituted alkyl group, a substituted or unsubstituted
cycloalkyl group, a substituted or unsubstituted aryl group, or an
electron-withdrawing group. R.sub.209 is preferably a substituted
or unsubstituted aryl group, and R.sub.210 is preferably an
electron-withdrawing group, more preferably a cyano group or a
fluoroalkyl group.
[0166] A represents a substituted or unsubstituted alkylene group,
a substituted or unsubstituted alkenylene group, or a substituted
or unsubstituted arylene group.
[0167] Among the compounds capable of generating an acid upon
irradiation with actinic rays or radiation, the compounds
represented by formulae (ZI) to (ZIII) are preferred, the compounds
represented by formulae (ZI) and (ZII) are more preferred, and the
compounds represented by formulae (ZI-1) to (ZI-3) are still more
preferred.
[0168] Furthermore, a compound capable of generating an acid
represented by any one of the following formulae (AC1) to (AC3)
upon irradiation with actinic rays or radiation is preferred.
##STR00032##
[0169] That is, a preferred acid generator is a compound where in
the structure of formula (ZI), X.sup.- is an anion selected from
formulae (AN1), (AN3) and (AN4), and a more preferred compound is a
compound where X.sup.- is an anion selected from formulae (AN3) and
(AN4).
[0170] Out of the compounds capable of decomposing upon irradiation
with actinic rays or radiation to generate an acid, particularly
preferred examples are set forth below.
##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037##
##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042##
##STR00043## ##STR00044## ##STR00045##
[0171] One of these acid generators may be used alone, or two or
more kinds thereof may be used in combination. In the case of using
two or more kinds in combination, compounds capable of generating
two or more kinds of organic acids differing in the total number of
atoms except for hydrogen atom by 2 or more are preferably
combined.
[0172] The content of the acid generator in the composition is
preferably from 0.1 to 20 mass %, more preferably from 0.5 to 10
mass %, still more preferably from 1 to 7 mass %, based on the
entire solid content of the negative resist composition.
[4] Quaternary Ammonium Salt Represented by Formula (2) (Component
(D))
[0173] The alkyl group, alkenyl group, aryl group and aralkyl group
as R.sub.3 to R.sub.6 in formula (2) each may have a substituent.
Also, two or more groups out of R.sub.3 to R.sub.6 may combine to
form an alicyclic or aromatic ring.
[0174] R.sub.3 to R.sub.6 each is preferably a linear or branched
alkyl group having a carbon number of 1 to 30, a linear or branched
alkenyl group having a carbon number of 1 to 30, an aryl group
having a carbon number of 6 to 18, an aralkyl group having a carbon
number of 7 to 18, or a group comprising a combination of these
groups.
[0175] These groups each may have a substituent, and examples of
the substituent include the same as those of the substituent of
R.sub.1 in formula (1), and a hydroxyl group. Furthermore, these
groups each may have therein a linking group such as ether group,
ester group and amide group.
[0176] R.sub.3 to R.sub.6 each is more preferably a linear or
branched alkyl group having a carbon number of 1 to 25, or a linear
or branched alkenyl group having a carbon number of 1 to 25, still
more preferably a linear or branched alkyl group having a carbon
number of 1 to 20.
[0177] In the R.sub.7CO.sub.2.sup.- group and
R.sub.7--SO.sub.3.sup.- group as B.sup.-, R.sub.7 preferably
represents a linear or branched alkyl group having a carbon number
of 1 to 8, a linear or branched alkenyl group having a carbon
number of 1 to 8, an aryl group having a carbon number of 6 to 18,
or an aralkyl group having a carbon number of 7 to 18.
[0178] B.sup.- is preferably an OH.sup.- group, a halogen atom
(e.g., chlorine, bromine, iodine, fluorine), or an
R.sub.7--CO.sub.2-- group (wherein R.sub.7 is preferably an alkyl
group having a carbon number of 1 to 12, more preferably from 1 to
6), more preferably an OH group, a halogen atom (e.g., chlorine,
bromine, iodine, fluorine, or an R.sub.7--CO.sub.2.sup.- group
(wherein R.sub.7 is an alkyl group having a carbon number of 1 to
4).
[0179] Specific preferred examples of the component (D) are set
forth below, but the present invention is not limited thereto.
##STR00046## ##STR00047## ##STR00048## ##STR00049##
[0180] The content of the component (D) for use in the present
invention is preferably from 0.01 to 10 mass %, more preferably
from 0.03 to 5 mass %, still more preferably from 0.05 to 3 mass %,
based on the solid content of the entire negative resist
composition.
[0181] In the present invention, one of the quaternary ammonium
salts as the component (D) may be used alone, or two or more kinds
thereof may be mixed and used.
[5] Organic Carboxylic Acid (Component (E))
[0182] The organic carboxylic compound as the component (E) is not
particularly limited and, for example, a saturated or unsaturated
aliphatic carboxylic acid, an alicyclic carboxylic acid, an
oxycarboxylic acid, an alkoxycarboxylic acid, a ketocarboxylic
acid, and an aromatic carboxylic acid all may be used. Examples
thereof include a monovalent or polyvalent aliphatic carboxylic
acid such as formic acid, acetic acid, propionic acid, butyric
acid, isobutyric acid, oxalic acid, malonic acid, succinic acid,
glutaric acid and adipic acid, an alicyclic carboxylic acid such as
1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexane-dicarboxylic
acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic
acid and 1,1-cyclohexyldiacetic acid, an unsaturated aliphatic
carboxylic acid such as acrylic acid, crotonic acid, isocrotonic
acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid,
propiolic acid, 2-butenoic acid, maleic acid, fumaric acid and
acetylene carboxylic acid, an oxycarboxylic acid such as oxyacetic
acid, an alkoxycarboxylic acid such as methoxyacetic acid and
ethoxyacetic acid, a ketocarboxylic acid such as pyruvic acid, a
benzoic acid, a p-hydroxybenzoic acid, an o-hydroxybenzoic acid, a
2-hydroxy-3-nitrobenzoic acid, a 3,5-dinitrobenzoic acid, a
2-nitrobenzoic acid, a 2,4-dinitrobenzoic acid, a
2,5-dinitrobenzoic acid, a 2,6-dinitrobenzoic acid, a
3,5-dinitrobenzoic acid, a 2-vinylbenzoic acid, a 4-vinylbenzoic
acid, a phthalic acid, a terephthalic acid, an isophthalic acid, a
2-naphthoic acid, a 1-hydroxy-2-naphthoic acid, and a
2-hydroxy-3-naphthoic acid. In the present invention, at the time
of forming a pattern by using an electron beam in vacuum, the
organic carboxylic acid may vaporize from the resist film surface
to contaminate the imaging chamber, and for this reason, the
preferred compound is an organic carboxylic acid having an
aromatic. Above all, for example, a benzoic acid, a
1-hydroxy-2-naphthoic acid and a 2-hydroxy-3-naphthoic acid are
more preferred.
[0183] One of these organic carboxylic acids may be use alone, or
two or more kinds thereof may be used in combination.
[0184] The amount of the organic carboxylic acid (E) blended is
preferably from 0.01 to 10 parts by mass, more preferably from 0.01
to 5 parts by mass, still more preferably from 0.01 to 3 parts by
mass, per 100 parts by mass of the alkali-soluble polymer (A).
[0185] Also, the blending ratio between the quaternary ammonium
salt as the component (D) and the organic carboxylic acid as the
component (E) is preferably (D)/(E)=5 to 95/95 to 5 (by mass), more
preferably (D)/(E)=10 to 90/90 to 10 (by mass).
[0186] The negative resist composition of the present invention may
further contain, if desired, a known compound such as
nitrogen-containing organic basic compound, dye, surfactant,
photolyzable base compound and photo-base generator. Examples of
these compounds include respective compounds described in
JP-A-2002-6500.
[0187] Also, examples of the solvent for use in the negative resist
composition of the present invention include solvents described
similarly in JP-A-2002-6500.
[0188] Preferred examples of the solvent include ethylene glycol
monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene
glycol monomethyl ether, propylene glycol monomethyl ether acetate,
propylene glycol monomethyl ether propionate, propylene glycol
monoethyl ether acetate, methyl 3-methoxypropionate, ethyl
3-ethoxypropionate, methyl .beta.-methoxyisobutyrate, ethyl
butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate,
isoamyl acetate, ethyl lactate, toluene, xylene, cyclohexyl
acetate, diacetone alcohol, N-methylpyrrolidone,
N,N-dimethylformamide, .gamma.-butyrolactone,
N,N-dimethylacetamide, propylene carbonate and ethylene carbonate.
One of these solvents may be used alone, or some may be used in
combination.
[0189] The solid materials of the resist composition preferably
dissolve in the solvent described above to a solid material
concentration of 1 to 40 mass %, more preferably from 1 to 30 mass
%, still more preferably from 3 to 20 mass %.
[0190] The negative resist composition of the present invention is
coated on a substrate to form a thin film. The thickness of this
coated film is preferably from 0.05 to 4.0 .mu.m.
[0191] In the present invention, a commercially available inorganic
or organic antireflection film may be used, if desired.
Furthermore, an antireflection film may be used by coating it on
the resist upper layer. As for this antireflection film, the
antireflection film described in JP-A-2002-6500 may be used.
[0192] The use mode of the negative resist composition of the
present invention is described below.
[0193] For example, in the production of a precision integrated
circuit device, the step of forming a pattern on a resist film
comprises coating the negative resist composition of the present
invention directly on a substrate (for example, a silicon/silicon
dioxide film, a glass substrate, a metal substrate, a silicon
nitride substrate, a titanium nitride substrate or a chromium oxide
substrate) or on an antireflection film previously provided by
coating on the substrate, irradiating the coated film with
radiation or actinic rays from a light source directly or through a
mask, and subjecting the resist film to heating, development,
rinsing and drying, whereby a good resist pattern can be formed. In
the present invention, the substrate is preferably a substrate
except for silicon (bare silicon), more preferably a substrate
having provided on the surface thereof a metal deposition film or a
metal-containing film, still more preferably a substrate on which
surface a vapor deposition film by Cr, Mo, MoSi, TaSi or an oxide
or nitride thereof or a film containing Cr, Mo, MoSi, TaSi or an
oxide or nitride thereof is provided, yet still more preferably a
substrate on which surface a vapor deposition film by Cr, MoSi,
TaSi or an oxide or nitride thereof is provided.
[0194] The light source is preferably a light source emitting light
at a wavelength of 150 to 250 nm (specifically, a KrF excimer laser
(248 nm), an ArF excimer laser (193 nm), or an F2 excimer laser
(157 nm)), an electron beam or an X-ray. In the present invention,
a device using an exposure light source emitting an electron beam
or an X-ray is most preferred.
[0195] The developer used for the negative resist composition of
the present invention may be a known developer, and examples
thereof include a developer described in JP-A-2002-6500.
EXAMPLES
[0196] The present invention is described in greater detail below
by referring to Examples, but the present invention should not be
construed as being limited thereto.
1. Synthesis Example of Constituent Material
(1) Alkali-Soluble Polymer (Component A)
Synthesis Example 1
Synthesis of Resin (29))
[0197] 4-Acetoxystyrene (3.9 g (0.024 mol)) and 0.8 g (0.006 mol)
of 4-methoxystyrene were dissolved in 30 ml of
1-methoxy-2-propanol, and under stirring in a nitrogen stream, 70
ml of a 1-methoxy-2-propanol solution containing 50 mg of
2,21-azobis(2,4-dimethylvaleronitrile) (V-65, trade name, produced
by Wako Pure Chemical Industries, Ltd.) as a polymerization
initiator, 9.1 g (0.056 mol) of 4-acetoxystyrene and 1.9 g (0.014
mol) of 4-methoxystyrene was added dropwise thereto at 70.degree.
C. over 2 hours. After 2 hours, 50 mg of the initiator was added,
and the reaction was further allowed to proceed for 2 hours.
Thereafter, the temperature was raised to 90.degree. C., and the
stirring was continued for 1 hour. The obtained reaction solution
was allowed to cool and then poured into 1 liter of ion-exchanged
water with vigorous stirring to precipitate a white resin. The
resin obtained was dried and then dissolved in 100 ml of methanol
and after adding 25% tetramethylammonium hydroxide to hydrolyze the
acetoxy group in the resin, the resulting solution was neutralized
with an aqueous hydrochloric acid solution to precipitate a white
resin. This resin was washed with ion-exchanged water and dried
under reduced pressure to obtain 11.6 g of Resin (29) of the
present invention. The obtained resin was measured for the
molecular weight by GPC and found to have a weight average
molecular weight (Mw, in terms of polystyrene) of 9,200 and a
dispersity (Mw/Mn) of 2.0.
[0198] The polymers as the component (A) for use in the present
invention were synthesized in the same manner.
(2) Synthesis of Crosslinking Agent (Component B)
Synthesis of (HM-1):
[0199]
1-[.alpha.-Methyl-.alpha.-(4-hydroxyphenyl)ethyl]-4-[.alpha.,.alpha-
.-bis(4-hydroxyphenyl)ethyl]benzene (Trisp-PA manufactured by
Honshu Chemical Industry Co., Ltd.) (20 g) was added to an aqueous
10% potassium hydroxide solution and dissolved with stirring, and
while stirring this solution, 60 ml of an aqueous 37% formalin
solution was gradually added thereto at room temperature over 1
hour. After further stirring at room temperature for 6 hours, the
solution was poured into an aqueous dilute sulfuric acid solution,
and the precipitate formed was collected by filtration, thoroughly
washed with water and then recrystallized from 30 ml of methanol to
obtain 20 g of white powder of Hydroxymethyl Group-Containing
Phenol Derivative [HM-1] having a structure shown below. The purity
was 92% (as determined by a liquid chromatography method).
##STR00050##
Synthesis of (MM-1):
[0200] Hydroxymethyl Group-Containing Phenol Derivative [HM-1] (20
g) obtained in synthesis Example above was added to 1 liter of
methanol and dissolved under heating with stirring. Subsequently, 1
ml of concentrated sulfuric acid was added to the resulting
solution, and the mixture was refluxed under heating for 12 hours.
After the completion of reaction, the reaction solution was cooled,
and 2 g of potassium carbonate was added thereto. This mixture was
sufficiently concentrated, and 300 ml of ethyl acetate was added
thereto. The resulting solution was washed with water and then
concentrated to dryness to obtain 22 g of a white solid of
Methoxymethyl Group-Containing Phenol Derivative [MM-1] having a
structure shown below. The purity thereof was 90% (as determined by
a liquid chromatography method).
##STR00051##
[0201] Furthermore, the phenol derivatives shown below were
synthesized in the same manner.
##STR00052## ##STR00053##
2. Examples
Example 1
(1) Preparation and Coating of Negative Resist Coating Solution
TABLE-US-00001 [0202] (Composition of Negative Resist Coating
Solution) Component (A): Resin (29) 0.40 g Component (B):
Crosslinking Agent MM-1 0.12 g Component (C): Acid Generator C-1
0.05 g Component (D): Ammonium Salt D-1 0.002 g Component (E):
Organic Carboxylic Acid 0.012 g E-1
[0203] The coating solution composition above was dissolved in 9.0
g of propylene glycol monomethyl ether acetate, and 0.001 g of
PF6320 (produced by OMNOVA, hereinafter simply referred to as
"W-1") as a surfactant was added thereto and dissolved. The
obtained solution was microfiltered through a membrane filter
having a pore size of 0.1 .mu.m to obtain a resist solution.
[0204] This resist solution was coated using a spin coater, Mark 8,
manufactured by Tokyo Electron Ltd. on a 6-inch wafer having
thereon Cr oxide vapor-deposited by the same processing as the
shielding film used for a photomask, and dried at 110.degree. C.
for 90 seconds on a hot plate to obtain a resist film having a
thickness of 0.3 .mu.m.
(2) Production of Negative Resist Pattern
[0205] This resist film was subjected to pattern irradiation using
an electron beam imaging device (HL750 manufactured by Hitachi,
Ltd., accelerating voltage: 50 KeV). After the irradiation, the
resist film was heated at 120.degree. C. for 90 seconds on a hot
plate, dipped in an aqueous 2.38 mass % tetramethylammonium
hydroxide (TMAH) solution for 60 seconds, rinsed with water for 30
seconds and dried. The obtained pattern was evaluated for the
sensitivity, resolving power, pattern profile and line edge
roughness by the following methods.
(2-1) Sensitivity
[0206] The cross-sectional profile of the pattern obtained was
observed by using a scanning electron microscope (S-4300,
manufactured by Hitachi, Ltd.), and the exposure dose necessary for
resolving a 0.15-.mu.m line (line:space=1:1) was defined as the
sensitivity.
(2-2) Resolving Power
[0207] The limiting resolving power (the line and space were
separated and resolved) at the exposure dose giving the sensitivity
above was defined as the resolving power.
(2-3) Pattern Profile
[0208] The cross-sectional profile of a 0.15-.mu.m line pattern at
the exposure dose giving the sensitivity above was observed by a
scanning electron microscope (S-4300, manufactured by Hitachi,
Ltd.) and rated on a three-point scale of rectangular, slightly
eroded, and eroded.
(2-4) Line Edge Roughness
[0209] The line width was measured at arbitrary 30 points in the
region of 50 .mu.m in the longitudinal direction of a 0.15-.mu.m
line pattern at the irradiation dosage giving the sensitivity
above, and the variation thereof was evaluated by 3.sigma..
(2-5) In-Vacuum PED Characteristics
[0210] The wafer was set in a vacuum chamber and irradiated with an
electron beam at the irradiation dose giving the sensitivity above,
and immediately or 3 hours after the irradiation, the wafer was
baked (heat-treated) at 120.degree. C. for 90 seconds and then
developed as described above to obtain a line pattern.
[0211] With respect to the 0.15-.mu.m line pattern obtained by
performing the baking and development immediately after the
irradiation of an electron beam and the 0.15-.mu.m line pattern
obtained by performing the baking and development 3 hours after the
irradiation of an electron beam, the line width was measured
through a scanning electron microscope (S-9220, manufactured by
Hitachi Ltd.), and the difference therebetween was defined as the
in-vacuum PED characteristic.
[0212] The results in Example 1 were good, that is, sensitivity;
6.0 .mu.C/cm.sup.2, resolving power: 0.11 .mu.m, pattern profile:
rectangular, line edge roughness: 6.0 nm, and in-vacuum PED
characteristic: 2.0 nm.
Examples 2 to 16
[0213] Preparation of the Resist Solution and Formation of the
negative pattern were performed in the same manner as in Example 1
except for using respective components shown in Table 1 below. In
Table 1, the ratio in using two or more kinds for a component is
the ratio by mass. The evaluation results are shown in Table 2.
Comparative Example 1
[0214] Preparation of the Resist Solution and Formation of the
negative pattern were performed in the same manner as in Example 1
except for, as shown in Table 1, not using an organic carboxylic
acid as the component (E). The evaluation results are shown in
Table 2.
Comparative Example 2
[0215] Preparation of the Resist Solution and Formation of the
negative pattern were performed in the same manner as in Example 1
except that, as shown in Table 1, a novolak resin not having a
repeating unit of formula (1) was used for the resin as the
component (A). The evaluation results are shown in Table 2.
Comparative Examples 3 and 4
[0216] Preparation of the Resist Solution and Formation of the
negative pattern were performed in the same manner as in Example 1
except for, as shown in Table 1, using only a known
nitrogen-containing organic basic compound without using a
quaternary ammonium salt as the component (D). The evaluation
results are shown in Table 2.
TABLE-US-00002 TABLE 1 Cross- Acid Organic linking Generator
Ammonium Carboxylic Agent as as Salt as Acid as Exam- Resin as
Component (A) Component Component Component Other Component Solvent
Surfactant ple (0.40 g) (B) (C) (D) Components (E) (9.0 g) (0.001
g) 1 (29) Mw = 9200 MM-1 C-1 D-1 E-1 S-1 W-1 x/y = 80/20 Mw/Mn =
2.0 0.12 g 0.05 g 0.002 g 0.012 g 2 (2) Mw = 5000 MM-1 C-1 D-1 E-3
S-1/S-2 = 80/20 W-1 Mw/Mn = 1.18 0.12 g 0.05 g 0.002 g 0.012 g 3
(1) Mw = 2500 MM-2 C-2 D-3 E-3 S-1 W-1 Mw/Mn = 1.15 0.11 g 0.05 g
0.003 g 0.012 g 4 (2) Mw = 7000 MM-3 C-3 D-10 E-3 S-1 W-2 Mw/Mn =
1.3 0.12 g 0.05 g 0.004 g 0.012 g 5 (27) Mw = 3500 MM-1 C-2 D-1 F-2
E-1 S-1/S-2 = 80/20 W-1 x/y = 85/15 Mw/Mn = 1.2 0.12 g 0.05 g 0.002
g 0.002 g 0.012 g 6 (25) Mw = 5000 MM-3 C-2/C-4 = 50/50 D-12 E-3
S-2 W-1 x/y = 60/40 Mw/Mn = 1.1 0.12 g 0.05 g 0.006 g 0.012 g 7
(32) Mw = 7500 MM-1 C-2 D-2 F-1 E-2 S-1/S-2 = 80/20 W-2 x/y = 80/20
Mw/Mn = 1.6 0.12 g 0.05 g 0.002 g 0.002 g 0.012 g 8 (2) Mw = 5000
CL-1 C-4 D-2 E-4 S-1 W-1 Mw/Mn = 1.18 0.12 g 0.05 g 0.002 g 0.012 g
9 (2) Mw = 5000 1.1/ MM-1 C-2/C-3 = 50/50 D-1 E-3 S-1/S-2 = 80/20
W-1 (1) Mw = 2500 1.1 = 75/25 0.12 g 0.05 g 0.002 g 0.024 g 10 (58)
Mw = 3500 MM-1 C-4 D-1 E-1 S-1/S-2 = 80/20 W-1 x/y = 80/20 Mw/Mn =
2.0 0.12 g 0.06 g 0.002 g 0.012 g 11 (2) Mw = 5000 MM-1 C-1 D-1 E-1
S-1/S-2 = 80/20 W-1 MW/Mn = 1.18 0.12 g 0.05 0.002 g 0.012 g 12
(25) Mw = 5000 MM-1 Z-85 D-1 E-1 S-1/S-2 = 80/20 W-2 x/y = 60/40
Mw/Mn = 1.1 0.08 g 0.04 g 0.002 g 0.012 g 13 (1) Mw = 2500 Mw/Mn =
1.15 MM-1 Z-85 D-1 E-2 S-1/S-2 = 80/20 W-2 (2) Mw = 5000 Mw/Mn =
1.18 0.08 g 0.04 g 0.002 g 0.012 g (1)/(2) = 25/75 (by mass) 14 (1)
Mw = 2500 Mw/Mn = 1.15 MM-1 Z-87 0.02 g D-1 E-1 S-1/S-2 = 80/20 W-2
(2) Mw = 5000 Mw/Mn = 1.18 0.08 g Z-88 0.02 g 0.002 g 0.012 g
(1)/(2) = 25/75 (by mass) 15 (1) Mw = 2500 Mw/Mn = 1.15 MM-1 Z-87
0.02 g D-1 E-1 S-1/S-2 = 80/20 W-2 (2) Mw = 5000 Mw/Mn = 1.18 0.08
g Z-88 0.02 g 0.002 g 0.012 g (1)/(2) = 25/75 (by mass) 16 (1) Mw =
2500 Mw/Mn = 1.15 MM-1 Z-88 D-1 E-1 S-1/S-2 = 80/20 W-2 (2) Mw =
5000 Mw/Mn = 1.18 0.08 g 0.04 g 0.002 g 0.012 g (1)/(2) = 25/75 (by
mass) Cross- Acid Organic linking Generator Ammonium Carboxylic
Agent as as Salt or Acid as Comparative Component Component
Comparative Other Component Solvent Surfactant Example Resin (0.40
g) (B) (C) Compound Components (E) (9.0 g) (0.001 g) 1 (29) Mw =
9200 MM-1 C-1 D-1 S-1 W-1 x/y = 80/20 Mw/Mn = 2.0 0.12 g 0.05 g
0.002 g 2 Novolak Resin AG-2B MM-1 C-1 D-1 E-1 S-1 W-1 (produced by
Gun Ei 0.12 g 0.05 g 0.002 g 0.012 g Chemical Industry Co., Ltd.) 3
(25) Mw = 5000 MM-1 C-4 F-3 E-1 S-1 W-1 x/y = 60/40 Mw/Mn = 1.1
0.12 g 0.05 g 0.004 g 0.012 g 4 (29) Mw = 9200 MM-1 C-1 G-1 E-1 S-1
W-1 x/y = 80/20 Mw/Mn = 2.0 0.12 g 0.05 g 0.002 g 0.012 g * When a
mixed solvent is used, the values in the Table indicate the mass
ratio.
[0217] The abbreviations in the Table are described below.
(Crosslinking Agent)
##STR00054##
[0219] The acid generators used in Table 1 are as follows. [0220]
C-1: Triphenylsulfonium nonafluorobutanesulfonate [0221] C-2:
Triphenylsulfonium pentafluorobenzenesulfonate [0222] C-3;
Triphenylsulfonium-2,4-dimethylbenzenesulfonate [0223] C-4:
Bisphenyl-4-cyclohexylphenylsulfonium
pentafluorobenzenesulfonate
[0224] The organic carboxylic acids used in Table 1 are as follows.
[0225] E-1: Benzoic acid [0226] E-2: 2-Naphthoic acid [0227] E-3:
2-Hydroxy-3-naphthoic acid [0228] E-4: o-Hydroxybenzoic acid
[0229] Other components used in Table 1 are as follows (all
produced by Tokyo Kasei Kogyo Co., Ltd.). [0230] F-1:
2,4,5-Triphenylimidazole [0231] F-2: 4-Dimethylaminopyridine [0232]
F-3: Triethylamine [0233] G-1: Trimethylammonium hydrochloride
[0234] The solvents used in Table 1 are as follows. [0235] S-1:
Propylene glycol monomethyl ether acetate [0236] S-2: Propylene
glycol monomethyl ether
[0237] The surfactants used in Table 1 are as follows. [0238] W-1:
PF6320 (produced by OMNOVA) [0239] W-2: Megafac F176 (produced by
Dainippon Ink & Chemicals, Inc.)
TABLE-US-00003 [0239] TABLE 2 Line Resolv- Pattern Edge In-Vacuum
ing Profile Rough- PED Sensitivity Power (rating on 3- ness
Character- (.mu.C/cm.sup.2) (.mu.m) stage scale) (nm) istic (nm)
Example 1 6.0 0.11 rectangular 6.0 2.0 2 5.0 0.10 rectangular 5.0
1.7 3 6.0 0.12 rectangular 6.0 2.0 4 7.0 0.12 rectangular 6.5 1.8 5
5.0 0.10 rectangular 5.5 1.5 6 6.0 0.13 rectangular 7.0 1.6 7 7.0
0.12 rectangular 6.5 1.5 8 6.0 0.14 rectangular 7.0 1.9 9 5.0 0.10
rectangular 5.0 1.6 10 5.0 0.10 rectangular 5.0 1.8 11 7.0 0.14
rectangular 6.5 1.9 12 7.0 0.12 rectangular 6.5 2.0 13 6.0 0.10
rectangular 6.0 1.8 14 5.0 0.10 rectangular 5.5 1.7 15 6.0 0.11
rectangular 6.0 1.6 16 5.0 0.11 rectangular 6.0 1.8 Comparative
Example 1 6.0 0.22 eroded 7.0 2.3 2 10.0 0.20 slightly 12.5 8.6
eroded 3 8.0 0.18 slightly 10.5 5.6 eroded 4 9.0 0.18 slightly 11.5
4.3 eroded
[0240] It is seen from Table 2 that the negative resist composition
of the present invention is excellent in terms of sensitivity,
resolving power, pattern profile, line edge roughness and in-vacuum
PED characteristic and assured of good performance.
[0241] According to the present invention, a negative resist
composition excellent in terms of sensitivity, resolving power,
pattern profile, line edge roughness and in-vacuum PED
characteristic, and a pattern forming method using the composition
can be provided.
[0242] The entire disclosure of each and every foreign patent
application from which the benefit of foreign priority has been
claimed in the present application is incorporated herein by
reference, as if fully set forth.
* * * * *