U.S. patent application number 13/336450 was filed with the patent office on 2012-07-12 for (meth)acrylate derivative, polymer and photoresist composition having lactone structure, and method for forming pattern by using it.
This patent application is currently assigned to NEC Corporation. Invention is credited to Etsuo Hasegawa, Shigeyuki Iwasa, Katsumi Maeda, Kaichiro Nakano.
Application Number | 20120178023 13/336450 |
Document ID | / |
Family ID | 26505189 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120178023 |
Kind Code |
A1 |
Maeda; Katsumi ; et
al. |
July 12, 2012 |
(METH)ACRYLATE DERIVATIVE, POLYMER AND PHOTORESIST COMPOSITION
HAVING LACTONE STRUCTURE, AND METHOD FOR FORMING PATTERN BY USING
IT
Abstract
Photoresist material for lithography using a light of 220 nm or
less comprising at least a polymer represented by following formula
(2) and a photo-acid generator for generating an acid by exposure:
##STR00001## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.5, each a
hydrogen atom or a methyl group; R.sup.4, an acid-labile group or
one of a specified subset of alicyclic hydrocarbon groups,
alicyclic hydrocarbon groups, or hydrocarbon groups; R.sup.6, a
hydrogen atom, a specified subset of hydrocarbon groups or
alicyclic hydrocarbon groups; x, y and z are optional values which
meet x+y+z=1, 0<x.ltoreq.1, 0.ltoreq.y<1 and 0.ltoreq.z<1;
resin having a (meth)acrylate unit of an alicyclic lactone
structure represented by formula (3): ##STR00002## wherein R.sup.8,
a hydrogen atom or a methyl group, and R.sup.9, one of a specified
subset of hydrocarbon groups.
Inventors: |
Maeda; Katsumi; (Tokyo,
JP) ; Iwasa; Shigeyuki; (Tokyo, JP) ; Nakano;
Kaichiro; (Tokyo, JP) ; Hasegawa; Etsuo;
(Tokyo, JP) |
Assignee: |
NEC Corporation
|
Family ID: |
26505189 |
Appl. No.: |
13/336450 |
Filed: |
December 23, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13088311 |
Apr 15, 2011 |
|
|
|
13336450 |
|
|
|
|
12230485 |
Aug 29, 2008 |
|
|
|
13088311 |
|
|
|
|
11713791 |
Mar 5, 2007 |
7432035 |
|
|
12230485 |
|
|
|
|
09750116 |
Dec 29, 2000 |
7186495 |
|
|
11713791 |
|
|
|
|
PCT/JP99/03580 |
Jul 2, 1999 |
|
|
|
09750116 |
|
|
|
|
Current U.S.
Class: |
430/281.1 ;
430/270.1 |
Current CPC
Class: |
C08F 222/14 20130101;
G03F 7/039 20130101; C08F 120/28 20130101; C07D 307/93 20130101;
G03F 7/0045 20130101; G03F 7/038 20130101; C08F 20/28 20130101;
G03F 7/004 20130101; Y10S 430/111 20130101; C08F 220/32 20130101;
G03F 7/0382 20130101 |
Class at
Publication: |
430/281.1 ;
430/270.1 |
International
Class: |
G03F 7/004 20060101
G03F007/004; G03F 7/027 20060101 G03F007/027 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 1998 |
JP |
188853/1998 |
Nov 18, 2008 |
JP |
328491-1998 |
Claims
1.-4. (canceled)
5. A photoresist material comprising: a polymer which is
represented by the formula (2) and has a weight-average molecular
weight of 2000 to 200000; and ##STR00068## a photo-acid generator
for generating an acid by exposure, wherein R.sup.1, R.sup.2,
R.sup.3 and R.sup.5 are each a hydrogen atom or a methyl group;
R.sup.4 is an acid-labile group, an alicyclic hydrocarbon group
having 7 to 13 carbon atoms, which has an acid.cndot.labile group,
an alicyclic hydrocarbon group having 7 to 13 carbon atoms, which
has a carboxyl group, or a hydrocarbon group having 3 to 13 carbon
atoms, which has an epoxy group; R.sup.6 is a hydrogen atom, a
hydrocarbon group having 1 to 12 carbon atoms, or an alicyclic
hydrocarbon group having 7 to 13 carbon atoms, which has a carboxyl
group; and x, y and z are optional values which meet x+y+z=1,
0<x.ltoreq.1, 0.ltoreq.y<1 and 0.ltoreq.z<1, wherein said
photo-acid generator for generating an acid by exposure comprises
derivatives of triphenylsulfonium salts.
6. The photoresist material according to claim 5, said photo-acid
generator for generating an acid by exposure is triphenylsulfonium
triflate.
7. A photoresist material comprising: a polymer; and a photo-acid
generator for generating an acid by exposure, wherein said polymer
which is obtained by polymerizing a (meth)acrylate derivative or by
copolymerizing a (meth)acrylate derivative with another
polymerizable compound, and has a weight-average molecular weight
of 2000 to 200000, wherein said (meth)acrylate derivative has an
alicyclic lactone structure which is represented by the formula
(4): ##STR00069## wherein R.sup.8 is a hydrogen atom or a methyl
group; R.sup.9 is a hydrocarbon group of 7 to 16 carbon atoms
having an alicyclic lactone structure, wherein said photo-acid
generator for generating an acid by exposure comprises derivatives
of triphenylsulfonium salts.
8. The photoresist material according to claim 7, said photo-acid
generator for generating an acid by exposure is triphenylsulfonium
triflate.
Description
TECHNICAL FIELD
[0001] The present invention relates to a novel (meth)acrylate
derivative, its polymer, particularly a resin for use in a
photoresist material in which a far ultraviolet light having a
wavelength of 220 nm or less is used as an exposure light, and a
photoresist composition.
BACKGROUND ART
[0002] In the field of the manufacture of various electron devices
typified by semiconductor devices in which fine working of
half-micron order is required, the further increase of density and
integration of these devices has been demanded. Therefore, a
photolithography technique required for the formation of fine
patterns has been more and more strict.
[0003] In particular, in the manufacture of DRAMs having an
integration degree of 1 gigabit or more in which a working
technique of 0.18 .mu.m or less is required, the utilization of
photolithography in which an ArF excimer laser (193 nm) is used has
been investigated in recent years [Donald C. Hofer et al., "Journal
of Photopolymer Science and Technology", Vol. 9, No. 3, p. 387-397
(1996)]. Accordingly, it has been desired to develop a resist
material suitable for the photolithography in which the ArF light
is used.
[0004] In developing this resist for ArF exposure, it is necessary
to improve a cost performance of the laser, because a life span of
a gas which is a raw material of the laser is short and a laser
apparatus itself is expensive. Therefore, high resolution
properties suitable for the fine working and the enhancement of
sensitivity are strongly desired.
[0005] As the resists having a heightened sensitivity, there are
well known chemically amplified resists in which a photo-acid
generator as a photosensitive material is utilized. For example, as
typical examples, resists comprising combinations of
triphenylsulfonium hexafluoroarcenate and
poly(p-tert-butoxycarbonyloxy-.alpha.-methylstyrene) are mentioned
in Japanese Patent Application Publication No. 27660/1990. Such
chemically amplified resists are now widely used as resists for a
KrF excimer laser [e.g., Hiroshi Ito, C. Grant Wilson, "American
Chemical Society Symposium Series", Vol. 242, p. 11-23 (1984)]. The
chemically amplified resists are characterized in that a proton
acid generated from the photo-acid generator as a contained
component by light irradiation gives rise to an acid catalytic
reaction with a resist resin or the like by a heat treatment after
exposure. As understood from the above, in the chemically amplified
resist, there can be achieved a much higher sensitivity as compared
with a conventional resist having a photoreactive efficiency (a
reaction per photon) of less than 1. Nowadays, most of the
developed resists are of the chemical amplification type.
[0006] However, in the case of the lithography in which a short
wavelength light of 220 nm or less typified by an ArF excimer laser
is used, the resists for forming fine patterns are required to
possess novel Characteristics which the conventional material
cannot satisfy, i.e., a high transparency to an exposure light of
220 nm or less, and a dry etching resistance.
[0007] A conventional photoresist material for g-line (438 nm),
1-line (365 nm) or the KrF excimer laser (248 nm) utilizes a resin
such as a novolak resin or a poly(p-vinylphenol) in which an
aromatic ring is present in a structural unit. The dry etching
resistance of this aromatic ring enables the etching resistance of
the resin to be maintained. As a negative photoresist material, a
crosslinking agent is further added to the resin. Examples of the
usable crosslinking agent include azide compounds such as
2,6-di(4'-azidobenzal)-4-methylcyclohexanone and
3,3'-diazidodiphenylsulfone as well as methylolmelamine resins.
However, the resin having the aromatic ring extremely strongly
absorbs a light having a wavelength of 220 nm or less. Therefore,
most of the exposure light is absorbed on the surface of the
resist, and so the exposure light cannot reach a substrate, with
the result that the fine resist pattern cannot be formed. For this
reason, the conventional resin cannot be directly applied to the
photolithography in which a short wavelength light of 220 nm or
less is used. Accordingly, a photoresist material is now desired
which contains no aromatic ring, has the etching resistance, and is
transparent to the wavelength light of 220 nm or less.
[0008] As polymeric compounds having the transparency to the ArF
excimer laser (193 nm) and the dry etching resistance, there have
been suggested copolymers each having an adamantyl methacrylate
unit which are alicyclic polymers [Takechi et al., "Journal of
Photopolymer Science and Technology", Vol. 5, No. 3, p. 439-446
(1992)] and copolymers each having an isobornyl methacrylate unit
[R. D. Allen et al., "Journal of Photopolymer Science and
Technology", Vol. 8, No. 4, p. 623-636 (1995) and Vol. 9, No. 3, p.
465-474 (1996)].
[0009] However, the (meth)acrylate derivative having an alicyclic
group which is used in the former resin does not have any polar
group having adhesive properties to a substrate (e.g., a carboxyl
group or a hydroxyl group). Therefore, a homopolymer of a monomer
having the alicyclic group is strongly hydrophobic and poor in the
adhesive properties to the substrate to be worked (e.g., a silicon
substrate), and so it is difficult to form a homogeneous coating
film with a high reproducibility. Furthermore, the former resin
does not have a residue capable of expressing a solubility
difference before and after exposure in an adamantane-including
residue, an to isobornyl-including residue or a menthyl-including
residue unit having the dry etching resistance, and therefore, any
pattern cannot be formed by the exposure. Thus, the former resin
can be utilized as the resin component of the positive resist only
by forming a copolymer of the former resin itself with a comonomer
such as t-butyl methacrylate or a tetrahydropyranyl-methacrylate
capable of exerting the solubility difference, or a comonomer such
as methacrylic acid having the adhesive properties to the
substrate. However, a content of the comonomer is required to be
about 50 mol %, and the dry etching resistance per comonomer is
noticeably low, so that a dry etching resistance effect by the
aliphatic group noticeably deteriorates. Accordingly, the former
resin is less practical as the resin having the dry etching
resistance.
SUMMARY OF THE INVENTION
[0010] Thus, an object of the present invention is to provide a
high-sensitive positive and negative photoresist materials having
excellent transparency and etching resistance for use in a
lithography in which an exposure light having a wavelength of 220
nm or less, in particular, an exposure light of 180 nm to 220 nm is
used.
[0011] Another object of the present invention is to provide a
method for forming a pattern by the use of these photoresist
materials.
[0012] Still another object of the present invention is to provide
a novel (meth)acrylate derivative and polymer for use in these
materials.
[0013] That is to say, the first aspect of the present invention is
directed to positive or negative photoresist materials which
comprises at least a polymer composed by copolymerizing
(meth)acrylate derivative represented by the formula (1), with
polymeric compounds and a photo-acid generator for generating an
acid by exposure:
##STR00003##
wherein R.sup.1 and R.sup.2 are each a hydrogen atom or a methyl
group.
[0014] As example of these polymer is represented by the following
formula (2):
##STR00004##
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.5 are each a hydrogen
atom or a methyl group; R.sup.4 is an acid-labile group, an
alicyclic hydrocarbon group having 7 to 13 carbon atoms, which has
an acid-liable group, an alicyclic hydrocarbon group having 7 to 13
carbon atoms, which has a carboxyl group, or a hydrocarbon group
having 3 to 13 carbon atoms, which has an epoxy group; R.sup.6 is a
hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or
an alicyclic hydrocarbon group having 7 to 13 carbon atoms, which
has a carboxyl group; and x, y and z are optional values which meet
x+y+z=1, 0<x.ltoreq.1, 0.ltoreq.y<1 and 0.ltoreq.z<1.
[0015] Furthermore, the above-mentioned material may contain a
polyhydric alcohol.
[0016] The second aspect of the present invention is directed to a
method for forming a pattern which comprises a step of applying the
above-mentioned photoresist material onto a substrate to be worked,
a step of exposing the material to a light having a wavelength of
180 to 220 nm, a step of carrying out baking, and a step of
performing development; and the exposure light may be an ArF
excimer laser light.
[0017] The third aspect of the present invention is directed to the
(meth)acrylate derivatives represented by the formula (1) and a
polymer composed by copolymerizing (meth)acrylate derivative
represented by the formula (1) with polymeric compounds.
[0018] The polymer of the present invention is excellent in dry
etching resistance and transparency, and the resist material using
the polymer of the present invention is excellent in resolution and
adhesive properties to the substrate, whereby the formation of a
fine pattern necessary to manufacture semiconductor elements is
possible.
[0019] The fourth aspect of the present invention is directed to a
resin for resist characterized in that, in the resin for resist,
the solubility to an alkaline aqueous solution of which increases
due to the decomposition of an acid-decomposable group thereof by
an action of an acid, said resin is the resin for resist having a
(meth)acrylate unit of an alicyclic lactone structure represented
by the formula (3), the resin for resist which is obtained by
polymerizing a (meth)acrylate derivative represented by the formula
(1) with other polymerizable compounds or the resin for resist
represented by the formula (2):
##STR00005##
wherein R.sup.8 is a hydrogen atom or a methyl group, and R.sup.9
is a hydrocarbon group of 7 to 16 carbon atoms having an alicyclic
lactone structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIGS. 1(A) to 1(D) are sectional views showing a formation
procedure of a negative resist pattern of the present
invention.
[0021] In these drawings: [0022] 1 . . . Substrate to be worked
[0023] 2 . . . Resist film [0024] 3 . . . Mask [0025] 4 . . .
Crosslinked region
DETAILED DESCRIPTION OF THE INVENTION
[0026] In the above-mentioned formula (1), R.sup.1 and R.sup.2 are
each a hydrogen atom or a methyl group.
[0027] In the above-mentioned formula (2), R.sup.1, R.sup.2,
R.sup.3 and R.sup.5 are each a hydrogen atom or a methyl group;
R.sup.4 is an acid-labile group, an alicyclic hydrocarbon group
having 7 to 13 carbon atoms, which has an acid-labile group, an
alicyclic hydrocarbon group having 7 to 13 carbon atoms, which has
a carboxyl group, or a hydrocarbon group having 3 to 13 carbon
atoms, which has an epoxy group; R.sup.6 is a hydrogen atom, a
hydrocarbon group having 1 to 12 carbon atoms, or an alicyclic
hydrocarbon group having 7 to 13 carbon atoms,
which has a carboxyl group.
[0028] Typical examples of the acid-labile group include, but are
not limited to, a t-butyl group, a tetrahydropyran-2-yl group, a
tetrahydrofuran-2-yl group, a 4-methoxytetrahydropyran-4-yl group,
a 1-ethoxyethyl group, a 1-butoxyethyl group, a 1-propoxyethyl
group, a 3-oxocyclohexyl group, a 2-methyl-2-adamantyl group, a
8-methyl-8-tricyclo[5.2.1.0.sup.2,6]decyl group, a
1,2,7,7-tetramethyl-2-norbornyl group, a 2-acetoxymenthyl group, a
2-hydroxymethyl group and a 1-methyl-1-cyclohexylethyl group.
[0029] Typical examples of the alicyclic hydrocarbon group having 7
to 13 carbon atoms which has an acid-labile group, alicyclic
hydrocarbon group having 7 to 13 carbon atoms which has the
carboxyl group include, but are not limited to, a
tricyclo[5.2.1.0.sup.2,6]decylmethyl group, a
tricyclo[5.2.1.0.sup.2,6]decyl group, an adamantyl group, a
norbornyl group, a methylnorbornyl group, an isobornyl group, a
tetracyclo[4.4.0.1.sup.2,5.1.sup.7,10] dodecyl group and a
methyltetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl group having
the carboxyl group or an ester group as shown in Table 1.
TABLE-US-00001 TABLE 1 Chemical Structure of Group
Tricyclo[5.2.1.0.sup.2,6]decyl- methyl group having the carboxyl
group or the ester group ##STR00006## or ##STR00007##
Tricyclo[5.2.1.0.sup.2,6]decyl group having the carboxyl group or
the ester group ##STR00008## or ##STR00009## Adamantyl group having
the carboxyl group or the ester group ##STR00010## Norbornyl group
having the carboxyl group or the ester group ##STR00011##
Methylnorbornyl group having the carboxyl group or the ester group
##STR00012## Isobornyl group having the carboxyl group or the ester
group ##STR00013## Tetracyclo[4.4.0.1.sup.2,5.1.sup.7,10] dodecyl
group having the carboxyl group or the ester group ##STR00014##
Methyltetracyclo[4.4.0.1.sup.2,5. 1.sup.7,10]dodecyl group having
the carboxyl group or the ester group ##STR00015##
[0030] R.sup.7 in Table 1 is a hydrogen atom or an acid-labile
group, and typical examples of the latter group include, but are
not limited to, a t-butyl group, a tetrahydropyran-2-yl group, a
tetrahydrofuran-2-yl group, a 4-methoxytetrahydropyran-4-yl group,
a 1-ethoxyethyl group, a 1-butoxyethyl group, a 1-propoxyethyl
group, a 3-oxocyclohexyl group, a 2-methyl-2-adamantyl group, a
8-methyl-8-tricyclo[5.2.1.0.sup.2,6]decyl group, a
1,2,7,7-tetramethyl-2-norbornyl group, a 2-acetoxymenthyl group, a
2-hydroxymenthyl group and a 1-methyl-1-cyclohexylethyl group.
[0031] Typical examples of the above-mentioned hydrocarbon group
having 3 to 13 carbon atoms which has the epoxy group include, but
are not limited to, a glycidyl group, a
3,4-epoxy-1-cyclohexylmethyl group, a 5,6-epoxy-2-norbornyl group,
a 5(6)-epoxyethyl-2-norbornyl group, a 5,6-epoxy-2-norbornylmethyl
group, a 3,4-epoxytricyclo[5.2.1.0.sup.2,6]decyl group, a
3,4-epoxytricyclo[5.2.1.0.sup.2,6]decyloxyethyl group, a
3,4-epoxytetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl group and a
3,4-epoxytetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecylmethyl group
as shown in Table 2.
TABLE-US-00002 TABLE 2 R.sup.4 Chemical Structure of Group Glycidyl
group ##STR00016## 3,4-Epoxy-1- cyclohexylmethyl group ##STR00017##
5,6-Epoxy-2-norbornyl group ##STR00018## 5(6)-Epoxyethyl-2-
norbornyl group ##STR00019## 5,6-Epoxy-2- norbornylmethyl group
##STR00020## 3,4-Epoxytricyclo [5.2.1.0.sup.2,6] decyl group
##STR00021## 3,4-Epoxytricyclo [5.2.1.0.sup.2,6] decyloxyethyl
group ##STR00022## 3,4-Epoxytetracyclo
[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl group ##STR00023##
3,4-Epoxytetracyclo [4.4.0.1.sup.2,5.1.sup.7,10]dodecyl- methyl
group ##STR00024##
[0032] Typical examples of the hydrocarbon group having 1 to 12
carbon atoms among the compounds represented by R.sup.6 include,
but are not limited to, a methyl group, an ethyl group, an n-propyl
group, an isopropyl group, an n-butyl group, an isobutyl group, a
t-butyl group, a cyclohexyl group, a tricyclo[5.2.1.0.sup.2,6]decyl
group, an adamantyl group, a norbornyl group, an isobornyl group
and a tetracyclo [4.4.0.1.sup.2,5.1.sup.7,10]dodecyl group.
[0033] Typical examples of the alicyclic hydrocarbon group having 7
to 13 carbon atoms which has the carboxyl group among the compounds
represented by R.sup.6 include, but are not limited to, a
carboxytricyclo[5.2.1.0.sup.2,6]decylmethyl group, a
carboxytricyclo[5.2.1.0.sup.2,6]decyl group, a carboxyadamantyl
group, a carboxynorbornyl group, a carboxymethylnorbornyl group, a
carboxylsobornyl group, a
carboxytetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl group and a
carboxymethyltetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl group as
shown in Table 3.
TABLE-US-00003 TABLE 3 Chemical Structure of Group
Carboxytricyclo[5.2.1.0.sup.2,6] decylmethyl group ##STR00025## or
##STR00026## Carboxytricyclo[5.2.1.0.sup.2,6] decyl group
##STR00027## or ##STR00028## Carboxyadamantyl group ##STR00029##
Carboxynorbornyl group ##STR00030## Carboxymethylnorbornyl group
##STR00031## Carboxyisobornyl group ##STR00032##
Carboxytetracyclo[4.4.0.1.sup.2,5. 1.sup.7,10]dodecyl group
##STR00033## Carboxymethyltetracyclo[4.4. 0.1.sup.2,5.
1.sup.7,10]dodecyl group ##STR00034##
[0034] Further, in the formula (3), R.sup.8 is a hydrogen atom or a
methyl group; R.sup.9 is a hydrocarbon group of 7 to 16 carbon
atoms having an alicyclic lactone structure. Typical examples of
the hydrocarbon group of 7 to 16 carbon atoms having an alicyclic
lactone structure include, but are not limited to, norbornyl groups
having a lactone structure, methylnorbornyl groups having a lactose
structure, tetracyclododecyl groups having a lactone structure,
methyltetracyclododecyl groups having a lactone structure and
adamantyl group having a lactone structure as shown in Table
13.
[0035] The resins for resist of the present invention have an
alicyclic lactone structure in the structure of the resins, and the
characteristic point resides in said lactone structure. Generally,
the lactone structure has a higher relative permittivity when
compared with an ester structure, an ether structure and an alcohol
structure (for example, when compared based on each of the
compounds having 4 carbon atoms, a relative permittivity of
.gamma.-butylolactone is 39, a relative permittivity of ethyl
acetate is 6.02, a relative permittivity of diethyl ether is 4.335,
and a relative permittivity of 1-butanole is 17.51 (A Handbook of
Chemistry, Fundamental Part II, revised 3rd edition, etc.). As a
result, the polarity of the resins having an alicyclic lactone
structure in the structure of the resins becomes high, and
consequently, the resist which uses the resins for photoresist of
the present invention has a superb adhesiveness against a
substrate.
[0036] Further, since the resins for photoresist of the present
invention have not only a lactone structure but also an alicyclic
hydrocarbon group, the resins have a superb characteristic of
excellent resistance property for dry-etching.
TABLE-US-00004 TABLE 13 Chemical Structure of R.sup.9 Norbornyl
group having a lactone structure (1) ##STR00035## Norbornyl group
having a lactone structure (2) ##STR00036## Norbornyl group having
a lactone structure (3) ##STR00037## Norbornyl group having a
lactone structure (4) ##STR00038## Methylnorbornyl group having a
lactone structure (1) ##STR00039## Methylnorbornyl group having a
lactone structure (2) ##STR00040## Methylnorbornyl group having a
lactone structure (3) ##STR00041## Methylnorbornyl group having a
lactone structure (4) ##STR00042## Tetracyclododecyl group having a
lactone structure (1) ##STR00043## Tetracyclododecyl group having a
lactone structure (2) ##STR00044## Tetracyclododecyl group having a
lactone structure (3) ##STR00045## Methyltetracyclododecyl group
having a lactone structure (1) ##STR00046## Methyltetracyclododecyl
group having a lactone structure (2) ##STR00047##
Methyltetracyclododecyl group having a lactone structure (3)
##STR00048## Adamantyl group having a lactone structure
##STR00049##
[0037] The polymer which can be used in the present invention can
be obtained by subjecting a (meth)acrylate monomer as a raw
material to a usual polymerization method such as radical
polymerization or ion polymerization. For example, the polymer can
be obtained by adding a suitable radical polymerization initiator
[e.g., azobisisobutyronitrile (AIBN)] to dry tetrahydrofuran under
an inert gas (argon, nitrogen or the like) atmosphere, and then
heating and stirring the mixture at 50 to 70.degree. C. for a
period of 0.5 to 12 hours. A weight-average molecular weight of the
polymer according to the present invention is in the range of 2000
to 200000, more preferably 3000 to 100000. Furthermore, by
selecting a feed ratio of the monomer for the copolymer and other
polymerization conditions, an optional copolymer can be
obtained.
[0038] Furthermore, the (meth)acrylate monomer containing the
alicyclic hydrocarbon group having 7 to 13 carbon atoms which has
the carboxyl group which is the raw material of the polymer can be
obtained by a method described in Japanese Patent Application
Laid-Open No. 259626/1996 which has already been disclosed by the
present inventors. Of the (meth)acrylate monomers each having the
epoxy group, for example,
3,4-epoxytricyclo[5.2.1.0.sup.2,6]decylacrylate can be obtained by
subjecting dicyclopentenyl acrylate to an epoxidizing reaction with
peracetic acid in acetic acid. Similarly, 5,6-epoxy-2-norbornyl
methacrylate can be obtained by subjecting
5-norbornene-2-methacrylate to an epoxidizing reaction.
[0039] A content of the polymer which is a constitutional factor of
the photoresist material according to the present invention is
usually in the range of 60 to 99.8 parts by weight, preferably 70
to 99 parts by weight with respect to 100 parts by weight of the
total constitutional components including the polymer itself.
[0040] A photo-acid generator which can be used in the present
invention is suitably a photo-acid generator which can generate an
acid by the irradiation of a light of 400 nm or less, preferably in
the range of 180 nm to 220 nm, and any photo-acid generator is
acceptable, so long as a mixture of the photo-acid generator, the
polymer of the present invention and the like can be sufficiently
dissolved in an organic solvent and this solution is capable of
forming a homogeneous coating film by a film formation method such
as spin coat. The photo-acid generators may be used singly or in
the form of a mixture of two or more thereof.
[0041] Examples of the usable photo-acid generator include
derivatives of triphenylsulfonium salts, other onium salts thereof
(e.g., compounds such as sulfonium salts, iodonium salts,
phosphonium salts, diazonium salts and ammonium salts),
2,6-dinitrobenzyl esters [O. Nalamasu et al., "SPIE Proceeding",
Vol. 2195, p. 137-151 (1994)], 1,2,3-tri(methanesulfonyloxy)benzene
[Takumi Ueno et al., "Proceeding of PME'89", Kodansha, p. 413-424
(1990)], and sulfosuccinimide disclosed in Japanese Patent
Application Laid-Open No. 5-134416. A content of the photo-acid
generator is usually in the range of 0.2 to 30 parts by weight,
preferably 1 to 15 parts by weight with respect to 100 parts by
weight of the total constitutional components including the
photo-acid generator itself.
[0042] When this content of the photo-acid generator is not less
than 0.2 part by weight, a sufficient sensitivity can be obtained,
and the formation of a pattern becomes easy. Conversely, if it is
more than 30 parts by weight, some problems occur. For example, it
is difficult to form a homogeneous coating film, and after
development, a scum is easily generated.
[0043] Examples of the above-mentioned polyhydric alcohol which can
be used in the present invention include, but are not limited to,
ethylene glycol, glycerol, 1,2-butanediol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, 1,2,4-butanetriol, 1,2-pentanediol,
1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 1,2-hexanediol,
1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol,
1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol,
1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,
1,3,5-cyclohexanetrimethanol, 1,2-cyclopentanediol,
1,3-cyclopentanediol, 1,2-cyclooctanediol, 1,5-cyclooctanediol,
tricyclodecanedimethanol, 2,3-norbornanediol,
2(3)-hydroxy-5,6-bis(hydroxymethyl)norbornane,
2,3-dihydroxy-5(6)-hydroxymethylnorbornane, 1,4-anhydroerythritol,
L-arabinose, L-arabitol, D-cellobiose, cellulose, 1,5-decalindiol,
glucose, galactose, lactose, maltose, mannose, mannitol and
tris(2-hydroxyethyl)isocyanurate. A content of the polyhydric
alcohol is usually in the range of 1 to 40 parts by weight,
preferably 5 to 30 parts by weight with respect to 100 parts by
weight of the total constitutional components including the
polyhydric alcohol itself. The polyhydric alcohols may be used
singly or in the form of a mixture of two or more thereof.
[0044] The photoresist material of the present invention can be
prepared by dissolving the total constitutional components in a
solvent so that the concentration of the total constitutional
components at its use may be in the range of 5 to 40% by weight,
and then filtering the resultant solution through a filter. As the
preferable solvent to be used, any solvent is acceptable, so long
as it can sufficiently dissolve the components of the resin, the
photo acid generator and the polyhydric alcohol, and from the
resultant solution, the homogeneous coating film can be formed in a
manner such as spin coat. Furthermore, the solvents may be used
singly or in the form of a mixture of two or more thereof.
[0045] Typical examples of the solvent include, but are not limited
to, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
tert-butyl alcohol, methyl cellosolve acetate, ethyl cellosolve
acetate, propylene glycol monoethyl ether acetate, methyl lactate,
ethyl lactate, 2-methoxybutyl acetate, 2-ethoxyethyl acetate,
methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl
3-methoxypropionate, N-methyl-2-pyrrolidinone, cyclohexanone,
cyclopentanone, cyclohexanol, methyl ethyl ketone, 1,4-dioxane,
ethylene glycol monomethyl ether, ethylene glycol monomethyl ether
acetate, ethylene glycol monoethyl ether, ethylene glycol
monoisopropyl ether, diethylene glycol monomethyl ether and
diethylene glycol dimethyl ether.
[0046] The "fundamental" constituents of the photoresist material
of the present invention are the above resins, the photo-acid
generator and the solvents. If necessary, other additives may be
added to the photoresist material of the present invention, and
examples of the additives include an organic base, a surface active
agent, a dyestuff, a basic additive, a stabilizer, an applicable
improver and a dye.
[0047] Furthermore, the present invention also provides a method
for forming a positive or negative pattern of the photoresist on a
substrate to be worked by the use of the above-mentioned
photoresist material. The method for forming the negative pattern
of the present invention is shown in FIG. 1. In the first place, as
shown in FIG. 1(A), the negative photoresist material of the
present invention is applied onto a substrate 1 to be worked, and
then prebaked at 60 to 170.degree. C. for 30 to 240 seconds by a
heating means such as a hot plate to form a resist film 2. Next, as
shown in FIG. 1(B), the resist film 2 is selectively exposed by the
use of an exposure device. After the exposure, the resist film 2 is
subjected to a heating treatment. As a result, in an exposed
region, an epoxy group causes a ring opening polymerization with
the is aid of the function of an acid generated from the photo-acid
generator to crosslink a resin as shown in FIG. 1(C).
Alternatively, when the photoresist material to which the
polyhydric alcohol has been added is used, the epoxy group reacts
not only with each other but also with the polyhydric alcohol by
the function of the acid in the exposed region, so that the
crosslinking of the resin is more promoted as compared with a case
where no polyhydric alcohol is added. In the last step, as shown in
FIG. 1 (D), the unexposed portion on the resist film 2 is
selectively dissolved and removed by an alkali developing solution
such as an aqueous tetramethylammonium hydroxide (TMAH) solution to
form the negative pattern.
[0048] The photoresist material of the present invention can be
utilized as a novel photoresist material having a high transparency
to a light of 220 nm or less and a high dry etching resistance.
Moreover, when the photoresist material of the present invention is
used in a photolithography step, a pattern can be formed.
[0049] Next, the present invention will be described in more detail
in accordance with examples, but the scope of to the present
invention should not be limited at all by these examples.
Example 1
Synthesis of 5-acryloyloxy-2,6-norbornanecarbolactone [an Acrylate
Having the Formula (1) in which R.sup.1 and R.sup.2 are Hydrogen
Atoms
##STR00050##
[0051] 10 g (0.0653 mol) of 5-hydroxy-2,6-norbornanecarbolactone
[H. B. Henbest et al., J. Chem. Soc., p. 221-226 (1959)], 9.49 g of
N,N-dimethylaniline and 20 mg of phenothiazine were dissolved in 60
ml of dry THF, followed by ice-cooling. To the mixture, a solution
obtained by dissolving 6.5 g of acryloyl chloride in 10 ml of dry
THF was added dropwise. After stirring for 2 hours under
ice-cooling and for 3 hours at room temperature, a filtrate was
concentrated under reduced pressure. Afterward, 250 ml of ether
were added to the resultant residue, and the solution was then
washed with 200 ml of 0.5 N hydrochloric acid, saturated brine, 200
ml of an aqueous 3% NaHCO.sub.3 solution, saturated brine and water
in this order. The ether layer was dried over MgSO.sub.4, and ether
was then distilled off under reduced pressure. The precipitated
white crystals were washed twice with 80 ml of hexane, thereby
obtaining 5.38 g of the desired product (white solid, yield=40% and
melting point=96.degree. C.).
[0052] .sup.1H-NMR (CDCl.sub.3) .delta. 1.66 (1H, d), 1.78 (1H, d),
1.99-2.11 (2H, m), 2.53-2.62 (2H, m), 3.18-3.25 (1H, m), 4.59 (1H,
d), 4.64 (1H, s), 5.89 (1H, dd), 6.11 (1H, dd), 6.43 (1H, dd): IR
(KBr) 2880, 2980 (.nu.C--H), 1712, 1773 (.nu.C.dbd.O), 1618, 1630
(.nu.C.dbd.C), 1186, 1205 (.nu.C--O) cm.sup.-1
Example 2
Synthesis of 5-methacryloyloxy-2,6-norbornanecarbolactone [a
methacrylate Represented by the Formula (1) Wherein R.sup.1 is a
Methyl Group and R.sup.2 is a Hydrogen Atom]
##STR00051##
[0054] The desired product was synthesized by the same procedure as
in Example 1 except that acryloyl chloride was replaced with
methacryloyl chloride (yield=20%).
[0055] .sup.1H-NMR (CDCl.sub.3) .delta. 1.62 (1H, d), 1.75 (1H, d),
1.92 (3H, s), 1.95-2.16 (2H, m), 2.53-2.66 (2H, m), 3.20-3.28 (1H,
m), 4.59 (1H, d), 4.65 (1H, s), 5.62 (1H, dd), 6.10 (1H, dd); IR
(KBr) 2880, 2982 (.nu.C--H), 1715, 1780 (.nu.C.dbd.O), 1630
(.nu.C.dbd.C), 1156, 1178 (.nu.C--O) cm.sup.-1
Example 3
Synthesis of 2-methyl-6-acryloyloxy-2,6-norbornanecarbolactone [an
Acrylate Represented by the Formula (1) Wherein R.sup.1 is a
Hydrogen Atom and R.sup.2 is a Methyl Group]
##STR00052##
[0057] The desired product was synthesized by the same procedure as
in Example 1 except that 5-hydroxy-2,6-norbornanecarbolactone was
replaced with 6-hydroxy-2,6-s norbornanecarbolactone [S. Beckmann
et al., Chem. Ber., Vol. 94, p. 48-58 (1961)] (yield=30%).
[0058] IR (KBr) 2880, 2982 (.nu.C--H), 1716, 1774 (.nu.C.dbd.O),
1619, 1629 (.nu.C--C), 1188, 1208 (.nu.C--O) cm.sup.-1
Example 4
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2 and R.sup.3 are Hydrogen Atoms;
R.sup.4 is a
t-butoxycarbonyltetracyclo-[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl
group; and x=0.7, y=0.3 and z=0]
##STR00053##
[0060] In a 100 ml round-bottom flask equipped with a reflux
condenser, 2.5 g of the acrylate obtained in Example 1 and 1.71 g
of t-butoxycarbonyltetracyclododecyl acrylate were dissolved in 23
ml of dry tetrahydrofuran, and to the mixture, 113 mg (30 mmol/l)
of AIBN was added, followed by stirring at 60 to 65.degree. C.
under an argon atmosphere. After 2 hours, the reaction mixture was
allowed to cool and then poured into 400 ml of methanol, and the
deposited precipitate was collected by filtration. Furthermore, the
reprecipitation/purification was carried out again to obtain 1.98 g
of the desired polymer (yield=47%). In this case, a
copolymerization ratio was 70:30 on the basis of an integration
ratio of .sup.1H-NMR (x=0.7, y=0.3). A weight-average molecular
weight (Mw) of the polymer by GPC analysis was 10800 (in terms of a
polystyrene), and its polydispersity (Mw/Mn) was 1.88.
Examples 5 and 6
[0061] Polymerization was carried out in the same manner as in
Example 4 except that a feed ratio of monomers was changed. Table 4
shows the feed ratios of the monomers, copolymerization ratios
(x/y) of polymers, and weight-average molecular weights of the
obtained copolymers.
TABLE-US-00005 TABLE 4 Weight-Average Molecular Feed Ratio x/y
Weight Example 5 0.5/0.5 0.49/0.51 13300 Example 6 0.35/0.65
0.35/0.65 11500
Examples 7 ad 8
[0062] Polymerization was carried out in the same manner as in
Example 4 except that an amount (concentration) of AIBN was
changed. Table 5 shows copolymerization ratios (x/y) of polymers,
weight-average molecular weights of the obtained copolymers, and
the like.
TABLE-US-00006 TABLE 5 Weight-Average AIBN Molecular Concentration
x/y Weight Example 7 5 mmol/l 0.7/0.3 154000 Example 8 70 mmol/l
0.69/0.31 3200
Example 9
[0063] Synthesis of a Polymer Having the Following Structure [in
the Formula (2). R.sup.1 and R.sup.2 are Hydrogen Atoms; R.sup.3 is
a Methyl Group; R.sup.4 is a
tetrahydropyranyloxycarbonyltetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl
Group; and x=0.7, y=0.3 and z=0]
##STR00054##
[0064] The desired polymer was synthesized by the same procedure as
in Example 4 except that t-butoxycarbonyltetracyclododecyl acrylate
was replaced with, tetrahydropyranyloxycarbonyltetracyclododecyl
methacrylate. Yield=52%, Mw=12000, and Mw/Mn=1.75.
Example 10
[0065] Synthesis of a Polymer Having the Following Structure (in
the Formula (2), R.sup.1 and R.sup.2 are Hydrogen Atoms; R.sup.3 is
a Methyl Group; R.sup.4 is a 2-methyl-2-adamantyl Group; and x=0.7,
y=0.3 and z=0]
##STR00055##
[0066] The desired polymer was synthesized by the same procedure as
in Example 4 except that t-butoxycarbonyltetracyclododecyl acrylate
was replaced with 2-methyl-2-adamantyl methacrylate. Yield=42%,
Mw=9500, and Mw/Mn=1.96.
Example 11
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1 and R.sup.2 are Hydrogen Atoms; R.sup.3 is a
Methyl Group; R.sup.4 is t-butyl methacrylate; and x=0.7, y=0.3 and
z=0]
##STR00056##
[0068] The desired polymer was synthesized by the same procedure as
in Example 4 except that t-butoxycarbonyltetracyclododecyl acrylate
was replaced with t-butyl methacrylate. Yield=60%, Mw=8400, and
Mw/Mn=1.74.
Example 12
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2 and R.sup.3 are Hydrogen Atoms;
R.sup.4 is a t-butoxycarbonylnorbornyl Group; and x=0.7, y=0.3 and
z=0]
##STR00057##
[0070] The desired polymer was synthesized by the same procedure as
in Example 4 except that t-butoxycarbonyltetracyclododecyl acrylate
was replaced with t-butoxycarbonylnorbornyl acrylate. Yield=44%,
Mw=9100, and Mw/Mn=1.72.
Example 13
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1 and R.sup.3 are Hydrogen Atoms; R.sup.2 is a
Methyl Group; R.sup.4 is a
t-butoxycarbonyltetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl
Group; and x=0.7, y=0.3 and z=0]
##STR00058##
[0072] The desired polymer was synthesized by the same procedure as
in Example 4 except that the acrylate obtained in Example 1 was
replaced with the acrylate obtained in Example 3. Yield=60%,
Mw=11300, and Mw/Mn=1.88.
Example 14
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2 and R.sup.3 are Hydrogen Atoms;
R.sup.4 is a
t-butoxycarbonyltetracyclo-[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl
Group; R.sup.5 is a Methyl Group; R.sup.6 is a Hydrogen Atom; and
x=0.6, Y=0.3 and z=0.1]
##STR00059##
[0074] In a 100 ml round-bottom flask equipped with a reflux
condenser, 3 g of the acrylate obtained in Example 1, 2.39 g of
t-butoxycarbonyltetracyclododecyl acrylate and 0.207 g of
methacrylic acid were dissolved in 30 ml of dry tetrahydrofuran,
and to the mixture, 147 mg (30 mmol/l) of AIBN was added, followed
by stirring at 60 to 65.degree. C. under an argon atmosphere. After
2 hours, the reaction mixture was allowed to cool and then poured
into 500 ml of methanol, and the deposited precipitate was
collected by filtration. Furthermore, the
reprecipitation/purification was carried out again to obtain 2.35 g
of the desired polymer (yield=42%). In this case, a
copolymerization ratio was 60:30:10 on the basis of an integration
ratio of .sup.1H-NMR (x=0.6, y=0.3, z=0.1). Mw=9700, and
Mw/Mn=1.74.
Example 15
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2, R.sup.3 and R.sup.2 are Hydrogen
Atoms; R.sup.4 is a t-butoxycarbonyltetracyclo
[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl Group; R.sup.6 is a
tricyclodecyl Group; and x=0.6, y=0.3 and z=0.1]
##STR00060##
[0076] The desired polymer was synthesized by the same procedure as
in Example 4 except that methacrylic acid was replaced with
tricyclodecyl acrylate (trade name FA-513A, made by Hitachi
Chemical Co., Ltd.). Yield=57%, Mw=13700, and Mw/Mn=2.13.
Example 16
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1 and R.sup.2 are Hydrogen Atoms; and x=1 and
y=z=0]
##STR00061##
[0078] In a 50 ml round-bottom flask equipped with a reflux
condenser, 3 g of the acrylate obtained in Example 1 were dissolved
in 16 ml of dry tetrahydrofuran, and to the mixture, 79 mg (30
mmol/l) of AIBN was added, followed by stirring at 60 to 65.degree.
C. under an argon atmosphere. After 1 hour, the reaction mixture
was allowed to cool and then poured into 200 ml of methanol, and
the deposited precipitate was collected by filtration. Furthermore,
the reprecipitation/purification was carried out again to obtain
1.8 g of the desired polymer (yield=60%). In this case, Mw=7100 and
Mw/Mn=2.05.
Example 17
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1 and R.sup.2 are Hydrogen Atoms; R.sup.3 is a
Methyl Group; R.sup.4 is a 2-acetoxymenthyl Group; and x=0.7, y=0.3
and z=0]
##STR00062##
[0080] The desired polymer was synthesized by the same procedure as
in Example 4 except that t-butoxycarbonyltetracyclododecyl acrylate
was replaced with 2-acetoxymenthyl methacrylate (which is mentioned
in Japanese Patent Application Laid-Open No. 335603/1996).
Yield=52%. Mw=8600, and Mw/Mn=1.77.
Example 18
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2, R.sup.3 and R.sup.5 are Hydrogen
Atoms; R.sup.4 is an epoxyethylnorbornyl Group; R.sup.6 is a
carboxytetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl Group; and
x=0.2, y=0.47 and z=0.33]
##STR00063##
[0082] In a 100 ml round-bottom flask equipped with a reflux
condenser, 2 g of the acrylate obtained in Example 1, 4.7 g of
epoxyethylnorbornyl acrylate and 4.38 g of carboxytetracyclododecyl
acrylate were dissolved in 60 ml of dry tetrahydrofuran, and to the
mixture, 295 mg of AIBN (the monomer/AIBN=28/1) was added, followed
by stirring at 60 to 65.degree. C. under an argon atmosphere. After
2 hours, the reaction mixture was allowed to cool and then poured
into 900 ml of a hexane/toluene (2/1) mixed solution, and the
deposited precipitate was collected by filtration. Furthermore, the
reprecipitation/purification was carried out again to obtain 5.69 g
of the desired polymer (yield=51%). In this case, a
copolymerization ratio was 20:47:33 on the basis of an integration
ratio of .sup.1H-NMR (x=0.2, y=0.47, z=0.33). A weight-average
molecular weight (Mw) of the polymer by GPC analysis was 8600 (in
terms of a polystyrene), and its polydispersity (Mw/Mn) was
1.45.
Examples 19, 20
[0083] Polymerization was carried out in the same manner as in
Example 18 except that a feed ratio of monomers was changed. Table
6 shows the feed ratios of the monomers, copolymerization ratios
(x/y/z) of polymers, and weight-average molecular weights of the
obtained copolymers.
TABLE-US-00007 TABLE 6 Weight-Average Molecular Feed Ratio x/y/z
Weight Example 19 0.1/0.65/0.25 0.1/0.66/0.24 7900 Example 20
0.4/0.4/0.2 0.4/0.42/0.18 8300
Examples 21, 22
[0084] Polymerization was carried out in the same manner as in
Example 18 except that an amount of AIBN (a monomer/AIBN) was
changed. Table 7 shows copolymerization ratios and weight-average
molecular weights of polymers.
TABLE-US-00008 TABLE 7 Weight-Average Molecular Monomer/AIBN x/y/z
Weight Example 21 50/l 0.21/0.46/0.33 14300 Example 22 200/l
0.2/0.48/0.32 36000
Example 23
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2 and R.sup.3 are Hydrogen Atoms;
R.sup.6 is an epoxyethylnorbornyl Group; R.sup.5 is a Methyl Group;
R.sup.6 is a Hydrogen Atom; and x=0.2, y=0.47 and z=0.33]
##STR00064##
[0086] The desired polymer was synthesized by the same procedure as
in Example 18 except that carboxytetracyclododecyl acrylate was
replaced with methacrylic acid. Yield=61%, Mw=10800, and
Mw/Mn=1.55.
Example 24
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1 and R.sup.5 are Methyl Groups; R.sup.2 and
R.sup.3 are Hydrogen Atoms; R.sup.4 is an epoxyethylnorbornyl
Group; R.sup.6 is a carboxynorbornyl Group; and x=0.2, y=0.47 and
z=0.33]
##STR00065##
[0088] The desired polymer was synthesized by the same procedure as
in Example 18 except that the monomer obtained in Example 1 was
replaced with the monomer obtained in Example 2 and
carboxytetracyclododecyl acrylate was replaced with
carboxynorbornyl acrylate. Yield=53%, Mw=16300, and Mw/Mn=1.4.
Example 25
Synthesis of a Polymer Having the Following Structure [in the
Formula (2), R.sup.1, R.sup.2 and R.sup.3 are Hydrogen Atoms;
R.sup.4 is a 3,4-epoxytricyclo[5.2.1.0.sup.2,6]decyl Group; R.sup.5
is a Methyl Group; R.sup.6 is a carboxytetracyclo
[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl Group; and x=0.2, y=0.47 and
z=0.33]
##STR00066##
[0090] The desired polymer was synthesized by the same procedure as
in Example 18 except that epoxyethylnorbornyl acrylate was replaced
with 3,4-epoxytricyclo[5.2.1.0.sup.2,6]decyl acrylate and
carboxytetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl acrylate was
replaced with carboxytetracyclo[4.4.0.1.sup.2,5.1.sup.7,10]dodecyl
methacrylate. Yield=46%, Mw=17000, and Mw/Mn=1.5.
Example 26
Synthesis of a Polyhydric Alcohol Having the Following Structure
(2,3-dihydroxy-5(6)-hydroxymethylnorbornane)
##STR00067##
[0092] 11 g of 2-hydroxymethyl-5-norboronene were dissolved in 21
ml of pyridine, and 11 ml of acetic anhydride were added dropwise
to the mixture, followed by stirring at room temperature for 12
hours. The resultant reaction mixture was poured into 100 ml of
water, and the organic layer was then extracted with 100 ml of
ethyl acetate. Afterward, the thus extracted organic layer was
washed with 0.5 N hydrochloric acid, a 3% aqueous sodium carbonate
solution and saturated saline in this order. This organic layer was
dried over magnesium sulfate, and ethyl acetate was distilled off
under reduced pressure, thereby obtaining 13 g of
2-acetoxy-5-norbornene. Next, 13 g of 2-acetoxy-5-norbornene were
added dropwise to a mixture of 50 ml of 90% formic acid and 13 ml
of 30% aqueous hydrogen peroxide under ice-cooling, followed by
stirring at room temperature for 12 hours. Formic acid was
distilled off under reduced pressure, and 30 ml of methanol, 13 g
of sodium hydroxide and 25 ml of water were added to the resultant
residue and reaction was then carried out at 45 to 50.degree. C.
for 1 hour. After the reaction solution was allowed to cool, the
resultant organic layer was extracted with 100 ml of ethyl acetate,
washed with saturated brine, and then dried over magnesium sulfate.
The solvent was distilled off under reduced pressure to obtain 5 g
of 2,3-dihydroxy-5(6)-hydroxymethylnorbornane.
[0093] IR (KBr) 3380 (.nu.O--H), 2950, 2860 (.nu.C--H), 1050
(.nu.C--O) cm.sup.-1
Example 27
Evaluation 1 of the Etching Resistance of a Polymer
[0094] 2 g of the polymer (resin) obtained in Example 5 were
dissolved in 10 g of propylene glycol monomethyl ether acetate, and
then filtered through a 0.2 .mu.m Teflon filter. Next, the filtered
mixture was applied onto a 3-inch silicon substrate by spin coat,
and then baked at 90.degree. C. for 60 seconds on a hot plate to
form a thin film having a thickness of 0.7 .mu.m thereon. An
etching velocity of the thus obtained film to a CF.sub.4 gas was
measured by the use of a DEM 451 reactive ion etching (RIE) device
made by Nichiden Aneluva Co., Ltd. (etching conditions: power=100
W, pressure=5 Pa, gas flow rate=30 sccm). The results are shown in
Table 8. Similarly, an etching rate of the polymer (resin) obtained
in Example 15 was also measured. As comparative examples, there are
also shown the results of a novolak resist (PFI-15A, made by
Sumitomo Chemical Co., Ltd.), a poly(p-vinylphenol) which is used
as a base resin for a KrF resist, and a poly(methyl methacrylate)
coating film which is a resin not having an alicyclic hydrocarbon
group in a molecular structure. Incidentally, the etching rate was
normalized on the basis of the novolak resist.
TABLE-US-00009 TABLE 8 Etching rate (Relative Ratio) Example 5 1.15
Example 15 1.15 Poly(methylmethacrylate) 1.9 Poly(p-vinylphenol)
1.2 Novolak Resist (PFI-15A) 1
[0095] It was apparent from the above-mentioned results that the
polymer (resin) of the present invention had the low etching rate
to the CF, gas, and so the polymer was excellent in dry etching
resistance.
Example 28
Evaluation 1 of the Transparency of a Polymer
[0096] 2.5 g of the polymer (resin) obtained in Example 5 were
dissolved in 10 g of propylene glycol monomethyl ether acetate, and
then filtered through a 0.2 .mu.m Teflon filter. Next, the filtered
mixture was applied onto a 3-inch quartz substrate by spin coat,
and then baked at 90.degree. C. for 60 seconds on a hot plate to
form a thin film having a thickness of 1 .mu.m. A transmittance of
the thus obtained thin film at 193.4 nm which was a central
wavelength of an ArF excimer laser light was measured by the use of
an ultraviolet visible spectrophotometer. Similarly, the
transmittance of the polymer (resin) obtained in Example 15 was
also measured.
[0097] The transmittance of the polymer obtained in Example 5 was
54%/.mu.m, and that of the polymer obtained in Example 15 was
55%/.mu.m. It was confirmed from these results that the polymer of
the present invention had a transparency which permitted the
polymer to be utilized as a single layer resist.
Example 29
Evaluation 1 of the Patterning of a Resist Using a Polymer
[0098] A resist comprising the following composition was
prepared:
[0099] (a) 2 g of the polymer (Example 5)
[0100] (b) 0.02 g of a photo-acid generator [triphenylsulfonium
triflate (TPS)]
[0101] (c) 11.5 g of propylene glycol monomethyl ether acetate
[0102] The mixture of the above-mentioned components was filtered
through a 0.2 .mu.m Teflon filter to prepare a resist. This resist
was applied onto a 4-inch silicon substrate by spin coat, and then
baked at 130.degree. C. for 1 minute on a hot plate to form a thin
film having a thickness of 0.4 .mu.m. The thus obtained wafer
having the film thereon was stilly put in a contact type exposure
experimental machine sufficiently purged with nitrogen. A mask
formed by depicting a pattern with chromium on a quartz plate was
closely attached onto the resist film, and this film was then
irradiated through the mask with an ArF excimer laser light.
Afterward, the resist film was immediately baked at 110.degree. C.
for 60 seconds on the hot plate, and development was then carried
out at a liquid temperature of 23.degree. C. for 60 seconds with a
2.38% aqueous TMAH solution in accordance with an immersion method.
In succession, a rinse treatment was done for 60 seconds with pure
water. As a result, the exposed portion alone on the resist film
was dissolved and removed with the developing solution to obtain a
positive pattern. A resist using the polymer obtained in Example 15
was also evaluated in the same manner. Table 9 shows the results of
sensitivity and resolution.
TABLE-US-00010 TABLE 9 Resolution Sensitivity (.mu.mL/S)
(mJ/cm.sup.2) Resist Including 0.19 6.5 Polymer of Example 5 Resist
Including 0.20 7 Polymer of Example 15
[0103] It was apparent from the above-mentioned results that the
photoresist material using the polymer of the present invention had
excellent resolution properties. In addition, since a phenomenon
such as pattern peeling was not observed, it could be confirmed
that the photoresist material was also excellent in adhesive
properties to the substrate.
Example 30
Evaluation 2 of the Etching Resistance of a Polymer
[0104] 2 g of the resin obtained in Example 18 were dissolved in 10
g of ethyl lactate, and then filtered through a 0.2 .mu.m Teflon
filter. Next, the filtered mixture was applied onto a 3-inch
silicon substrate by spin coat, and then baked at 90.degree. C. for
60 seconds on a hot plate to form a thin film having a thickness of
0.7 .mu.m. An etching velocity of the thus obtained film to a CF,
gas was measured by the use of a DEM 451 reactive ion etching (RIE)
device made by Nichiden Aneluva Co., Ltd. (etching conditions:
power=100 W, pressure=5 Pa, gas flow rate=30 sccm). The results are
shown in Table 10. Similarly, an etching rate of the resin obtained
in Example 25 was also measured. As comparative examples, there are
also shown the results of a novolak resist (PFI-15A, made by
Sumitomo Chemical Co., Ltd.), a poly(p-vinylphenol) which is used
as a base resin for a KrF resist, and a poly(methyl methacrylate)
coating film which is a resin not having an alicyclic hydrocarbon
group in a molecular structure. Incidentally, the etching rate was
normalized on the basis of the novolak resist.
TABLE-US-00011 TABLE 10 Etching rate (Relative Ratio) Example 18
1.1 Example 25 1.05 Poly(methyl methacrylate) 1.9
Poly(p-vinylphenol) 1.2 Novolak Resist (PFI-15A) 1
[0105] It was apparent from the above-mentioned results that the
resin of the present invention had the low etching velocity to the
CF, gas, and so the polymer was excellent in dry etching
resistance.
Example 31
Evaluation 2 of the Transparency of a Polymer
[0106] 2.5 g of the resin obtained in Example 18 were dissolved in
10 g of ethyl lactate, and then filtered through a 0.2 .mu.m Teflon
filter. Next, the filtered mixture was applied onto a 3-inch quartz
substrate by spin coat, and then baked at 90.degree. C. for 60
seconds on a hot plate to form a thin film having a thickness of 1
.mu.m. A transmittance of the thus obtained film at 193.4 nm which
was a central wavelength of an ArF excimer laser light was measured
by the use of an ultraviolet visible spectrophotometer. Similarly,
the transmittance of the resin obtained in Example 25 was also
measured.
[0107] As a result, the transmittance of the polymer obtained in
Example 18 was 53%/.mu.m, and that of the polymer obtained in
Example 25 was 57%/.mu.m. It was confirmed from these results that
the polymer of the present invention had a transparency which
permitted the polymer to be utilized as a single layer resist.
Example 32
Evaluation 2 of the Patterning of a Resist Using a Polymer
[0108] A resist solution comprising the following composition was
prepared:
[0109] (a) 2 g of the polymer (Example 18)
[0110] (b) 0.04 g of a photo-acid generator [triphenylsulfonium
triflate (TPS)]
[0111] (c) 11.5 g of ethyl lactate
[0112] The mixture of the above-mentioned components was filtered
through a 0.2 .mu.m Teflon filter to prepare a resist solution.
This resist solution was applied onto a 4-inch silicon substrate by
spin coat, and then baked at 80.degree. C. for 1 minute on a hot
plate to form a thin film having a thickness of 0.4 .mu.m. The thus
obtained wafer having the film thereon was stilly put in a close
type exposure experimental machine sufficiently purged with
nitrogen. A mask formed by depicting a pattern with chromium on a
quartz plate was closely attached onto the resist film, and this
film was then irradiated through the mask with an ArF excimer laser
light. Afterward, the resist film was immediately baked at
130.degree. C. for 60 seconds on the hot plate, and development was
then carried out at a liquid temperature of 23.degree. C. for 60
seconds with a 2.38% aqueous TMAH solution in accordance with an
immersion method. In succession, a rinse treatment was done for 20
seconds with pure water. As a result, the exposed portion alone on
the resist film was dissolved and removed with the developing
solution to obtain a negative pattern. A resist using the polymer
obtained in Example 25 was also evaluated in the same manner. Table
11 shows the results of sensitivity and resolution.
TABLE-US-00012 TABLE 11 Resolution Sensitivity (.mu.mL/S)
(mJ/cm.sup.2) Resist Including 0.25 32 Resin of Example 18 Resist
Including 0.24 28 Resin of Example 25
Example 33
Evaluation 3 of the Patterning of a Resist Using a Polymer
[0113] A resist comprising the following composition was
prepared:
[0114] (a) 2 g of the polymer (Example 18)
[0115] (b) 0.3 g of the polyhydric alcohol (Example 26)
[0116] (c) 0.04 g of a photo-acid generator (triphenylsulfonium
triflate)
[0117] (c) 11.5 g of ethyl lactate
[0118] Exposure, baking and a development treatment were carried
out in the same manner as in Example 32, followed by the evaluation
of patterning. Similarly, the evaluation was also made for a resist
to which tricyclo[5.2.1.0.sup.2,6]decanedimethanol (made by Tokyo
Chemical Industry Co., Ltd.) was added as the polyhydric alcohol.
Table 12 shows the results of sensitivity and resolution.
TABLE-US-00013 TABLE 12 Resolution Sensitivity (.mu.mL/S)
(mJ/cm.sup.2) Resist Including 0.19 6.8 Polyhydric Alcohol of
Example 26 Resist Including 0.20 9.4 Tricyclodecanedimethanol as
Polyhydric Alcohol
[0119] It was understood from the results of Examples 32 and 33
that the negative photoresist material of the present invention had
excellent resolution properties. In addition, since a phenomenon
such as pattern peeling was not observed, it could be confirmed
that the photoresist material was also excellent in adhesive
properties to the substrate. Furthermore, it was also apparent that
the sensitivity and the resolution could be improved by adding the
polyhydric alcohol.
[0120] As described above, in the resin for resist of the present
invention, by using a resin having an alicyclic lactone structure a
negative type chemical amplification resist having not only
excellent resistance for dry-etching and transparency, but also
superb resolution property and good adhesiveness against substrate
can be obtained, thus it is possible to form a fine pattern
necessary for producing semiconductor device.
* * * * *