U.S. patent application number 11/434917 was filed with the patent office on 2006-09-14 for novel fluorine-containing polymer, resist composition prepared from same and novel fluorine-containing monomer.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. Invention is credited to Takayuki Araki, Takuji Ishikawa, Meiten Koh.
Application Number | 20060204893 11/434917 |
Document ID | / |
Family ID | 26623667 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060204893 |
Kind Code |
A1 |
Araki; Takayuki ; et
al. |
September 14, 2006 |
Novel fluorine-containing polymer, resist composition prepared from
same and novel fluorine-containing monomer
Abstract
There is provided a fluorine-containing copolymer having an
aliphatic monocyclic structure in the polymer trunk chain which has
a number average molecular weight of from 500 to 1,000,000 and is
represented by the formula (Ma): -(M1)-(M2a)-(N)- (Ma) in which the
structural unit M1 is a structural unit derived from an ethylenic
monomer having 2 or 3 carbon atoms and at least one fluorine atom,
the structural unit M2a is at least one structural unit which
introduces an aliphatic monocyclic structure in the polymer trunk
chain and is represented by the formula (a): ##STR1## wherein
R.sup.1 is at least one hydrocarbon group selected from the group
consisting of a divalent hydrocarbon group having 1 to 8 carbon
atoms and constituting a ring which may be further substituted with
a hydrocarbon group or a fluorine-containing alkyl group and a
divalent hydrocarbon group having ether bond which has the sum of
carbon atoms and oxygen atoms of 2 to 8, constitutes a ring and may
be further substituted with a hydrocarbon group or a
fluorine-containing alkyl group; R.sup.2 is an alkylene group which
has 1 to 3 carbon atoms and constitutes a ring; R.sup.3 and R.sup.4
are the same or different and each is a divalent alkylene group
which has 1 or 2 carbon atoms and constitutes a ring; n1, n2 and n3
are the same or different and each is 0 or 1, the structural unit N
is a structural unit derived from a monomer copolymerizable with
the monomers to introduce the structural units M1 and M2a, and the
structural units M1, M2a and N are contained in amounts of from 1
to 99% by mole, from 1 to 99% by mole and from 0 to 98% by mole,
respectively. The fluorine-containing polymer possesses excellent
dry etching resistance and transparency in a vacuum ultraviolet
region.
Inventors: |
Araki; Takayuki; (Osaka,
JP) ; Ishikawa; Takuji; (Osaka, JP) ; Koh;
Meiten; (Osaka, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
|
Family ID: |
26623667 |
Appl. No.: |
11/434917 |
Filed: |
May 17, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10815801 |
Apr 2, 2004 |
|
|
|
11434917 |
May 17, 2006 |
|
|
|
PCT/JP02/10242 |
Oct 2, 2002 |
|
|
|
10815801 |
Apr 2, 2004 |
|
|
|
Current U.S.
Class: |
430/270.1 |
Current CPC
Class: |
C07F 9/5435 20130101;
C07C 2601/08 20170501; C07C 2602/42 20170501; G03F 7/0045 20130101;
C07C 43/313 20130101; C08F 8/00 20130101; C07F 9/5442 20130101;
C07F 9/59 20130101; C07C 25/22 20130101; G03F 7/0392 20130101; C07C
31/38 20130101; C07C 49/167 20130101; C07C 45/63 20130101; Y10S
430/108 20130101; C07F 9/5456 20130101; C07C 33/423 20130101; C08F
8/00 20130101; C08F 2800/10 20130101; C08F 8/00 20130101; C08F
234/00 20130101; C07C 49/167 20130101; C08F 220/22 20130101; C08F
214/265 20130101; C07C 45/63 20130101; C07C 35/52 20130101; C08F
214/186 20130101; C08F 8/00 20130101; G03F 7/0046 20130101; C07C
25/18 20130101; C07C 33/44 20130101; C08F 232/04 20130101; G03F
7/0382 20130101; C07C 25/13 20130101; C07F 9/5407 20130101; G03F
7/0395 20130101; C07F 9/5449 20130101; C08F 214/18 20130101; Y10S
430/106 20130101; Y02P 20/55 20151101; C08F 2800/20 20130101; C08F
8/00 20130101 |
Class at
Publication: |
430/270.1 |
International
Class: |
G03C 1/76 20060101
G03C001/76 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 3, 2001 |
JP |
2001-307823 |
Feb 28, 2002 |
JP |
2002-54964 |
Claims
1-38. (canceled)
39. A fluorine-containing polymer having a number average molecular
weight of from 500 to 1,000,000 represented by the formula (61):
-(M3-1)-(N-3-1)- (61) in which M3-1 is a structural unit
represented by the formula (53): ##STR168## wherein Rf.sup.50 and
Rf.sup.51 are the same or different and each is a perfluoroalkyl
group having 1 to 20 carbon atoms; X.sup.10 and X.sup.11 are the
same or different and each is H, F, an alkyl group having 1 to 20
carbon atoms or a fluorine-containing alkyl group which has 1 to 20
carbon atoms and may have ether bond; X.sup.12 is hydrogen atom,
fluorine atom, an alkyl group having 1 to 20 carbon atoms, a
fluorine-containing alkyl group which has 1 to 20 carbon atoms and
may have ether bond, OH group or a group represented by the
formula: ##STR169## wherein Rf.sup.52 and Rf.sup.53 are the same or
different and each is a perfluoroalkyl group having 1 to 20 carbon
atoms; R.sup.50 is at least one selected from an alkylene group or
fluorine-containing alkylene group which has 1 to 3 carbon atoms
and constitutes a ring; R.sup.51 and R.sup.52 are the same or
different and each is at least one selected from a divalent
hydrocarbon group which has 1 to 7 carbon atoms and constitutes a
ring, oxygen atom, a divalent hydrocarbon group having ether bond
which has the sum of oxygen atoms and carbon atoms of 2 to 7 and
constitutes a ring, a divalent fluorine-containing alkylene group
which has 1 to 7 carbon atoms and constitutes a ring or a divalent
fluorine-containing alkylene group having ether bond which has the
stun of oxygen atoms and carbon atoms of 2 to 7 and constitutes a
ring; the sum of carbon atoms constituting a trunk chain in
R.sup.51 and R.sup.52 is not more than 7, and OH group or a group
represented by the formula: ##STR170## wherein Rf.sup.52 and
Rf.sup.53 are as defined above, may be bonded to any of carbon
atoms in R.sup.51; R.sup.53 and R.sup.54 are the same or different
and each is a divalent alkylene group having 1 or 2 carbon atoms or
a divalent fluorine-containing alkylene group having 1 or 2 carbon
atoms; n50, n51, n52, n53 and n54 are the same or different and
each is 0 or 1, N3-1 is a structural unit derived from a monomer
copolymerizable with the monomer to introduce the structural unit
M3-1, and the structural units M3-1 and N3-1 are co in amounts of
from 0.1 to 100% by mole and from 0 to 99.9% by mole, respectiv
40. A fluorine-containing polymer having a number average molecular
weight of from 500 to 1,000,000 represented by the formula (61):
-(M3-1)-(N-3-1)- (61) in which M3-1 is a structural unit
represented by the formula (54): ##STR171## wherein Rf.sup.50 is a
perfluoroalkyl group having 1 to 20 carbon atoms: X.sup.10 and
X.sup.11 are the same or different and each is H, F, an alkyl group
having 1 to 20 carbon atoms or a fluorine-containing alkyl group
which has 1 to 20 carbon atoms and may have ether bond; R.sup.50 is
at least one selected from an alkylene group or fluorine-containing
alkylene group which has 1 to 3 carbon atoms and constitutes a
ring; R.sup.51 and R.sup.52 are the same or different and each is
at least one selected from a divalent hydrocarbon group which has 1
to 7 carbon atoms and constitutes a ring, oxygen atom, a divalent
hydrocarbon group having ether bond which has the sum of oxygen
atoms and carbon atoms of 2 to 7 and constitutes a ring, a divalent
fluorine-containing alkylene group which has 1 to 7 carbon atoms
and constitutes a ring or a divalent fluorine-containing alkylene
group having ether bond which has the sum of oxygen atoms and
carbon atoms of 2 to 7 and constitutes a ring; the sum of carbon
atoms constituting a trunk chain in R.sup.51 and R.sup.52 is not
more than and OH group or a group represented by the formula:
##STR172## wherein Rf.sup.52 and Rf.sup.53 are the same or
different and each is a perfluoroalkyl group having 1 to 20 carbon
atoms, may be bonded to any of carbon atoms in R.sup.51, R.sup.53,
and R.sup.54 are the same or different and each is a divalent
alkylene group having 1 or 2 carbon atoms or a divalent
fluorine-containing alkylene group having 1 or 2 carbon atoms; n50,
n51, n52, n53 and n54 are the same or different and each is 0 or 1,
N3-1 is structural unit derived from a monomer copolymerizable with
the monomer to introduce the structural unit M3-1, and the
structural units M3-1 and N3-1 are contained in amounts of from 0.1
to 100% by mole and from 0 to 99.9% by mole, respectively.
41. The fluorine-containing polymer of claim 39, wherein in the
formula (53), X.sup.12 is fluorine atom or a perfluoroalkyl group
having 1 to 20 carbon atoms.
42. The fluorine-containing polymer of claim 40, wherein in
R.sup.51 and R.sup.52 of the formula (54), at least one of fluorine
atom or a perfluoroalkyl group having 1 to 20 carbon atoms is
bonded to at least one of neighboring carbon atoms of the carbon
atom bonded to OH group.
43. The fluorine-containing polymer of claim 40, wherein in the
formula (54), the structure of R.sup.51 contains at least one
structural unit represented by the formula: ##STR173## wherein
R.sup.52 is as defined above.
44. The fluorine-containing polymer of claim 39, wherein when in
the structural unit M3-1, the carbon atom bonded to OH group is
named the first carbon atom and a structure consisting of the first
carbon atom up to the neighboring fourth carbon atom is assumed to
be a model structure, the model structure having OH group satisfies
Equation 1: .DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH).ltoreq.75
(Equation 1) wherein H(M-OH) is a produced enthalpy of the model
structure, H(M-O.sup.-) is a produced enthalpy of the model
structure after dissociation of the OH group and a produced
enthalpy of hydrogen ion is assumed to be a constant of 200
kJ/mol.
45. The fluorine-containing polymer of claim 40, wherein when in
the structural unit M3-1, the carbon atom bonded to OH group is
named the first carbon atom and a structure consisting of the first
carbon atom up to the neighboring fourth carbon atom is assumed to
be a model structure, the model structure having OH group satisfies
Equation 1: .DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH).ltoreq.75
(Equation 1) wherein H(M-OH) is a produced enthalpy of the model
structure, H(M-O.sup.-) is a produced enthalpy of the model
structure after dissociation of the OH group and a produced
enthalpy of hydrogen ion is assumed to be a constant of 200
kJ/mol.
46. A fluorine-containing cyclopentene having OH group represented
by the formula (70): ##STR174## wherein Rf.sup.70 is a
perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.70 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms; X.sup.71 is hydrogen atom, fluorine atom, a hydrocarbon
group having 1 to 20 carbon atoms or a perfluoroalkyl group having
1 to 20 carbon atoms; X.sup.72 is hydrogen atom, fluorine atom, OH
group, a hydrocarbon group having 1 to 20 carbon atoms or a
perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.73 is
hydrogen atom, fluorine atom, a hydrocarbon group having 1 to 20
carbon atoms or a perfluoroalkyl group having 1 to 20 carbon atoms;
when X.sup.72 is OH group, X.sup.73 is not fluorine atom.
47. The fluorine-containing cyclopentene having OH group of claim
46, wherein in the formula (70), both of X.sup.70 and X.sup.71 are
fluorine atoms or perfluoroalkyl groups having 1 to 20 carbon
atoms.
48. The fluorine-containing cyclopentene having OH group of claim
46, wherein in the formula (70), X.sup.72 is OH group and X.sup.73
is a perfluoroalkyl group having 1 to 20 carbon atoms.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. application Ser.
No. 10/815,801 filed Apr. 2, 2004, which is a continuation-in-part
of PCT international application No. PCT/JP02/10242 filed on Oct.
2, 2002; the above-noted applications incorporated herein by
reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a novel fluorine-containing
unsaturated cyclic compound, a novel fluorine-containing polymer
having an aliphatic monocyclic structure in its trunk chain, and a
chemically amplifying photoresist composition which is obtained
from the fluorine-containing polymer, is excellent in transparency
and possesses improved dry etching resistance.
[0003] As a result of an increasing necessity for high integration
of a large scale integrated circuit (LSI), microfabrication
technology is required for photolithography. In order to satisfy
such requirements, there have been tried to use, as exposure light
sources, a deep ultraviolet, a KrF excimer laser beam (wavelength:
248 nm) and a ArF excimer laser beam (wavelength: 193 nm) which
have a wavelength shorter than conventional g-rays (wavelength: 436
nm) and i-rays (wavelength: 365 nm). Those light sources are put
into practical use.
[0004] Recently a process using a F.sub.2 laser beam (wavelength:
157 nm) having a wavelength in a vacuum ultraviolet region has been
studied in an ultra-microfabrication technology and is considered
promising as an exposure technology aiming at a technology node of
0.1 .mu.m.
[0005] On the other hand, in the pattern formation, a chemically
amplifying resist which becomes advantageous in transparency,
resolution, sensitivity and dry etching resistance in cases of
energy rays having various wavelengths has been studied. The
chemically amplifying resist means, for example, in case of a
positive resist, an energy-sensitive composition comprising a resin
being soluble in an alkali developing solution and having an
introduced substituent which has an effect of inhibiting
dissolution of the resin but is deprotected due to action of an
acid, and a compound which generates an acid by irradiation of
energy rays such as light and electron beam (hereinafter referred
to as a photoacid generator). When the composition is irradiated
with light or electron beam, an acid is generated from the
photoacid generator, and by heating (post-exposure bake, which may
be hereinafter referred to as "PEB") after the exposure to light,
the substituent which has been giving a dissolution inhibiting
effect on the resin is deprotected due to action of an acid. As a
result, the exposed portion becomes soluble in alkali, and by
treating the exposed portion with an alkali developing solution, a
positive resist pattern can be obtained. In that case, the acid
acts as a catalyst and exhibits its effect in a very small amount.
Also action of the acid becomes active by the PEB and a chemical
reaction is accelerated like a chain reaction, and thus sensitivity
is enhanced.
[0006] Examples of conventional resins for chemically amplifying
resist are phenol resins in which a part or the whole of hydroxyl
is protected by a protective group such as acetal or ketal (KrF
resist), methacrylic acid resins in which an acid-labile ester
group is introduced to carboxyl (ArF resist) and the like.
[0007] However those conventional resist polymers have strong
absorption in a wavelength range of a vacuum ultraviolet region and
have a significant problem that transparency against F.sub.2 laser
beam having a wavelength of 157 nm which is studied in a process
for ultra fine pattern is low (an absorption coefficient is high).
Therefore for exposing with F.sub.2 laser, it is necessary to make
a resist film thickness very thin and it is substantially difficult
to use the polymers as a single layer F.sub.2 resist.
[0008] R. R. Kunz, T. M. Bloomstein, et al. suggest in Journal of
Photopolymer Science and Technology (Vol. 12, No. 4 (1999) 561-569)
that fluorocarbons have good transparency at 157 nm as compared
with other various materials and have possibility of use as a
F.sub.2 resist.
[0009] However in that literature, there is only description that
existing fluorocarbon polymers are high in transparency at 157 nm,
but there is no description as to preferable structure of
fluorine-containing polymers. Also, for example, with respect to a
fluorine-containing polymer having functional group necessary for a
positive type or negative type chemically amplifying resist,
neither evaluation of transparency nor synthesis of the polymer was
made. Moreover the literature does not suggest a
fluorine-containing base polymer material being preferable as a
chemically amplifying resist and a preferable resist composition
obtained therefrom at all, and there is found no possibility of
forming a F.sub.2 resist pattern by using a fluorine-containing
polymer.
[0010] Thereafter A. E. Feiring, et al. of E. I. du Pont de Nemours
and Company disclosed in WO00/17712 pamphlet (published Mar. 30,
2000) that a specific fluorine-containing polymer is useful for
F.sub.2 resist application.
[0011] That pamphlet describes the use of a fluorine-containing
polymer having a structural unit of fluoroolefin and a structural
unit having a polycyclic condensed structure which is mainly a
structural unit derived from norbornene.
[0012] Also an acid-labile (acid-decomposable) functional group
necessary for a positive type resist is introduced to the
fluorine-containing polymer by copolymerizing a conventional
acrylic, methacrylic, norbornene or vinyl ester monomer with a
monomer having an introduced acid-labile (acid-decomposable)
functional group.
[0013] Further thereafter A. E. Feiring, et al. of E. I. du Pont de
Nemours and Company disclosed in WO00/67072 pamphlet (published
Nov. 9, 2000) that a fluorine-containing polymer having
--C(Rf)(Rf')OH or --C(Rf)(Rf')O--Rb is useful for F.sub.2 resist
application.
[0014] In that pamphlet, a structural unit of norbornene in which
--C(Rf)(Rf')OH or --C(Rf)(Rf')O--Rb is bonded through a part of
--CH.sub.2OCH.sub.2-- is disclosed. Further there is disclosed
norbornene derivatives having --C(Rf)(Rf')OH or --C(Rf)(Rf')O--Rb
as an example of a fluorine-containing polymer to be used for a
resist.
[0015] However in those patent publications, there is no
description as to the use of a fluorine-containing copolymer
comprising a structural unit of fluoroolefin and a structural unit
having an aliphatic monocyclic structure in its trunk chain, and
further there is no description as to an aliphatic monocyclic
structure to which a functional group necessary for a resist is
introduced.
[0016] Further Katsuyama, et al. of Matsushita Electric Industrial
Co., Ltd. proposed a method of forming a pattern with exposure
light having a wavelength of from 1 to 180 nm using a resist
material containing halogen atom, etc. (JP2000-321774A published
Nov. 24, 2000). However there is disclosed only a methacrylic resin
having a structural unit of methacrylic acid ester having
--CH.sub.2CF.sub.3 group and --CH(CF.sub.3).sub.2 group in its side
chain as a base resin having halogen atom for a resist, and neither
a resin containing fluorine atom in its trunk chain nor a polymer
having an aliphatic monocyclic structure in its trunk chain is
disclosed. Also there is disclosed no polymer which has, in an
aliphatic monocyclic structure, a functional group and is capable
of working as a chemically amplifying resist (positive type or
negative type).
[0017] There is generally known that dry etching resistance of a
polymer is enhanced by introducing a norbornene backbone to the
polymer. However transparency, particularly transparency in a
vacuum ultraviolet region of conventional norbornene derivatives
cannot be said to be sufficient.
[0018] The present inventors have found that fluoroolefins
represented by tetrafluoroethylene have good copolymerizability
with unsaturated compounds (monomers) of aliphatic monocyclic
structure, and a novel fluorine-containing polymer was obtained. It
has been considered that dry etching resistance of monocyclic
compounds was insufficient as compared with compounds having
polycyclic condensed structure. However the present inventors have
found that the copolymer which is obtained in the present invention
and comprises fluoroolefin and an unsaturated compound (monomer) of
aliphatic monocyclic structure has dry etching resistance higher
than that of an unsaturated compound having polycyclic condensed
structure, for example, norbornene.
[0019] Also it was found that transparency in a vacuum ultraviolet
region is excellent as compared with the use of norbornene.
[0020] Also studies have been made as to introduction of an
acid-reactive functional group necessary for a resist, and as a
result, it was found that in addition to the fluoroolefin and
unsaturated compound (monomer) of aliphatic monocyclic structure, a
specific ethylenic monomer having an acid-reactive functional group
has good copolymerizability, which made it possible to introduce an
acid-reactive functional group to a polymer. Further the present
inventors have found a fluorine-containing polymer in which an
acid-reactive functional group is introduced directly to a
monocyclic structure and also a novel unsaturated compound of
monocyclic structure having an acid-reactive functional group and
partly having fluorine atoms. The copolymer comprising such a novel
unsaturated compound of monocyclic structure and a fluoroolefin
exhibits excellent dry etching resistance and high transparency
when used for a resist.
SUMMARY OF THE INVENTION
[0021] The first object of the present invention is to provide a
novel fluorine-containing polymer having an aliphatic monocyclic
structure in its trunk chain.
[0022] The second object of the present invention is to provide a
novel fluorine-containing unsaturated aliphatic monocyclic compound
having functional group.
[0023] The third object of the present invention is to provide a
chemically amplifying photoresist composition which comprises a
fluorine-containing aliphatic monocyclic polymer having an
acid-reactive group and a photoacid generator and can be used for a
patterning process using F.sub.2 laser as light source.
[0024] The present inventors have made intensive studies to achieve
the above-mentioned objects and as a result, have found a novel
fluorine-containing unsaturated aliphatic monocyclic compound and a
novel fluorine-containing polymer having an aliphatic monocyclic
structure in its trunk chain and have found that the
fluorine-containing polymer is useful as a polymer for a
resist.
[0025] Namely, the present inventors have made various studies with
respect to copolymerization of a fluoroolefin, typically
tetrafluoroethylene with unsaturated monocyclic hydrocarbon
compounds and as a result, have found that a specific unsaturated
monocyclic hydrocarbon compound which can constitute a ring in its
trunk chain has good copolymerizability with fluoroolefins having 2
or 3 carbon atoms, and have found a novel fluorine-containing
polymer.
[0026] The first of the present invention relates to novel
fluorine-containing polymers. The first novel fluorine-containing
polymer is a fluorine-containing polymer having an aliphatic
monocyclic structure in the polymer trunk chain which has a number
average molecular weight of from 500 to 1,000,000 and is
represented by the formula (Ma): -(M1)-(M2a)-(N)- (Ma) in which the
structural unit M1 is a structural unit derived from an ethylenic
monomer having 2 or 3 carbon atoms and at least one fluorine atom,
the structural unit M2a is at least one structural unit which
introduces an aliphatic monocyclic structure in the polymer trunk
chain and is represented by the formula (a): ##STR2## wherein
R.sup.1 is at least one hydrocarbon group selected from the group
consisting of a divalent hydrocarbon group which has 1 to 8 carbon
atoms and constitutes a ring (which may be further substituted with
a hydrocarbon group or a fluorine-containing alkyl group) and a
divalent hydrocarbon group having ether bond which has the sum of
carbon atoms and oxygen atoms of 2 to 8 and constitutes a ring
(which may be further substituted with a hydrocarbon group or a
fluorine-containing alkyl group); R.sup.2 is an alkylene group
which has 1 to 3 carbon atoms and constitutes a ring; R.sup.3 and
R.sup.4 are the same or different and each is a divalent alkylene
group having 1 or 2 carbon atoms; n1, n2 and n3 are the same or
different and each is 0 or 1, the structural unit N is a structural
unit derived from a monomer copolymerizable with the monomers to
introduce the structural units M1 and M2a, and the structural units
M1, M2a and N are contained in amounts of from 1 to 99% by mole,
from 1 to 99% by mole and from 0 to 98% by mole, respectively.
[0027] The second fluorine-containing polymer of the first
invention is a fluorine-containing polymer having an aliphatic
monocyclic structure in the polymer trunk chain which has a number
average molecular weight of from 500 to 1,000,000 and is
represented by the formula (Mb): -(M1)-(M2b)-(N)- (Mb) in which the
structural units M1 and N are as defined in the above-mentioned
formula (Ma), the structural unit M2b is at least one structural
unit which introduces an aliphatic monocyclic structure in the
trunk chain and is represented by the formula (b): ##STR3## wherein
R.sup.1, R.sup.2, R.sup.3, R.sup.4, n1, n2 and n3 are as defined in
the above-mentioned formula (a); Z are the same or different and
each is: ##STR4## wherein Z.sup.1 is at least one functional group
selected from the group consisting of OH group, COOH group, a
derivative of carboxylic acid group and a functional group
protected by a protective group which can convert the functional
group to OH group by reaction with an acid; R.sup.5 is a divalent
organic group; n5 is 0 or 1; n4 is an integer of from 1 to 3, and
the structural units M1, M2b and N are contained in amounts of from
1 to 99% by mole, from 1 to; 99% by mole and from 0 to 98% by mole,
respectively.
[0028] The second of the present invention relates to a
fluorine-containing unsaturated cyclic compound represented by the
formula (1): ##STR5## wherein Z.sup.3 are the same or different and
each is --Rf.sup.3-Z.sup.4, in which Z.sup.4 is at least one
functional group selected from the group consisting of OH group,
COOH group, a derivative of carboxylic acid group and a functional
group protected by a protective group which can converted the
functional group to OH group by reaction with an acid; Rf.sup.3 is
a fluorine-containing alkylene group which has 1 to 30 carbon atoms
and may have ether bond; n11 is an integer of from 1 to 4.
[0029] The third of the present invention relates to a photoresist
composition which comprises:
(A-1) a fluorine-containing polymer having OH group, COOH group
and/or a group which can be dissociated by an acid and converted to
OH group or COOH group,
(B) a photoacid generator and
(C) a solvent,
in which the fluorine-containing polymer (A-1) is a polymer
comprising a structural unit derived from a fluoroolefin and a
structural unit derived from a monomer introducing an aliphatic
monocyclic structure in the polymer trunk chain.
[0030] The fourth of the present invention relates to a photoresist
composition which comprises:
[0031] (A-2) a fluorine-containing polymer having OH group which
has recurring units of an aliphatic monocyclic structure in the
polymer trunk chain, in which OH group or a moiety having OH group
is bonded to the carbon atom constituting the aliphatic monocyclic
structure,
(B) a photoacid generator and
(C) a solvent,
[0032] in which when in the recurring units of the aliphatic
monocyclic structure of the fluorine-containing polymer (A-2), the
carbon atom bonded to OH group is named the first carbon atom and a
structure consisting of the first carbon atom up to the neighboring
fourth carbon atom is assumed to be a model structure, the model
structure having OH group satisfies Equation 1:
.DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH).ltoreq.75 (Equation 1) and
further Equation 2: .DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH).ltoreq.70
(Equation 2) wherein H(M-OH) is a produced enthalpy of the model
structure, H(M-O.sup.-) is a produced enthalpy of the model
structure after dissociation of the OH group and a produced
enthalpy of hydrogen ion is assumed to be a constant of 200
kJ/mol.
[0033] The fifth of the present invention relates to a photoresist
composition which comprises:
[0034] (A-3) a fluorine-containing polymer having OH group which
has recurring units of an aliphatic monocyclic structure in the
polymer trunk chain, in which OH group or a moiety having OH group
is bonded to the carbon atom constituting the aliphatic monocyclic
structure,
(B) a photoacid generator and
(C) a solvent,
[0035] in which the recurring units of the aliphatic monocyclic
structure of the fluorine-containing polymer (A-3) have a structure
represented by the formula (50): ##STR6## wherein Rf.sup.11 is a
perfluoroalkyl group having 1 to 20 carbon atoms; Z.sup.10 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms.
[0036] The OH group in the recurring units of the aliphatic
monocyclic structure may be protected by a protective group.
[0037] The sixth of the present invention relates to a photoresist
composition which comprises:
[0038] (A-5) a fluorine-containing polymer having OH group which
has recurring units of an aliphatic monocyclic structure in the
polymer trunk chain, in which OH group or a moiety having OH group
is bonded to the carbon atom constituting the aliphatic monocyclic
structure,
(B) a photoacid generator and
(C) a solvent,
[0039] in which the fluorine-containing polymer (A-5) is a polymer
having a structural unit represented by the formula (53): ##STR7##
wherein Rf.sup.50 and Rf.sup.51 are the same or different and each
is a perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.10 and
X.sup.11 are the same or different and each is H, F, an alkyl group
having 1 to 20 carbon atoms or a fluorine-containing alkyl group
which has 1 to 20 carbon atoms and may have ether bond; X.sup.12 is
hydrogen atom, fluorine atom, an alkyl group having 1 to 20 carbon
atoms, a fluorine-containing alkyl group which has 1 to 20 carbon
atoms and may have ether bond, OH group or a group represented by
the formula: ##STR8## wherein Rf.sup.52 and Rf.sup.53 are the same
or different and each is a perfluoroalkyl group having 1 to 20
carbon atoms; R.sup.50 is at least one selected from an alkylene
group or fluorine-containing alkylene group which has 1 to 3 carbon
atoms and constitutes a ring; R.sup.51 and R.sup.52 are the same or
different and each is at least one selected from a divalent
hydrocarbon group which has 1 to 7 carbon atoms and constitutes a
ring, oxygen atom, a divalent hydrocarbon group having ether bond
which has the sum of oxygen atoms and carbon atoms of 2 to 7 and
constitutes a ring, a divalent fluorine-containing alkylene group
which has 1 to 7 carbon atoms and constitutes a ring or a divalent
fluorine-containing alkylene group having ether bond which has the
sum of oxygen atoms and carbon atoms of 2 to 7 and constitutes a
ring; the sum of carbon atoms constituting a trunk chain in
R.sup.51 and R.sup.52 is not more than 7, and OH group or a group
represented by the formula: ##STR9## wherein Rf.sup.52 and
Rf.sup.53 are as defined above, may be bonded to any of carbon
atoms in R.sup.51; R.sup.53 and R.sup.54 are the same or different
and each is a divalent alkylene group having 1 or 2 carbon atoms or
a divalent fluorine-containing alkylene group having 1 or 2 carbon
atoms; n50, n51, n52, n53 and n54 are the same or different and
each is 0 or 1.
[0040] The seventh of the present invention relates to a
photoresist composition which comprises:
[0041] (A-5) a fluorine-containing polymer having OH group which
has recurring units of an aliphatic monocyclic structure in the
polymer trunk chain, in which OH group or a moiety having OH group
is bonded to the carbon atom constituting the aliphatic monocyclic
structure,
(B) a photoacid generator and
(C) a solvent,
[0042] in which the fluorine-containing polymer (A-5) is a polymer
having a structural unit represented by the formula (54): ##STR10##
wherein Rf.sup.50 is a perfluoroalkyl group having 1 to 20 carbon
atoms; X.sup.10 and X.sup.11 are the same or different and each is
H, F, an alkyl group having 1 to 20 carbon atoms or a
fluorine-containing alkyl group which has 1 to 20 carbon atoms and
may have ether bond; R.sup.50 is at least one selected from an
alkylene group or fluorine-containing alkylene group which has 1 to
3 carbon atoms and constitutes a ring; R.sup.51 and R.sup.52 are
the same or different and each is at least one selected from a
divalent hydrocarbon group which has 1 to 7 carbon atoms and
constitutes a ring, oxygen atom, a divalent hydrocarbon group
having ether bond which has the sum of oxygen atoms and carbon
atoms of 2 to 7 and constitutes a ring, a divalent
fluorine-containing alkylene group which has 1 to 7 carbon atoms
and constitutes a ring or a divalent fluorine-containing alkylene
group having ether bond which has the sum of oxygen atoms and
carbon atoms of 2 to 7 and constitutes a ring; the sum of carbon
atoms constituting a trunk chain in R.sup.51 and R.sup.52 is not
more than 7, and OH group or a group represented by the formula:
##STR11## wherein Rf.sup.52 and Rf.sup.53 are the same or different
and each is a perfluoroalkyl group having 1 to 20 carbon atoms, may
be bonded to any of carbon atoms in R.sup.51; R.sup.53 and R.sup.54
are the same or different and each is a divalent alkylene group
having 1 or 2 carbon atoms or a divalent fluorine-containing
alkylene group having 1 or 2 carbon atoms; n50, n51, n52, n53 and
n54 are the same or different and each is 0 or 1.
[0043] It is preferable that in the formula (53), X.sup.12 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon atoms
and that in R.sup.51 or R.sup.52 of the formula (54), at least one
fluorine atom or perfluoroalkyl group having 1 to 20 carbon atoms
is bonded to at least one of neighboring carbon atoms of the carbon
atom bonded to the OH group.
[0044] Further in the formula (54), also preferred is a structural
unit having, in the structure of R.sup.51, at least one structural
unit represented by the formula: ##STR12## wherein Rf.sup.52 is as
defined above.
[0045] The eighth of the present invention relates to a
fluorine-containing polymer having a number average molecular
weight of from 500 to 1,000,000 which is represented by the formula
(61): -(M3-1)-(N-3-1)- (61) in which M3-1 is a structural unit
represented by the formula (53): ##STR13## wherein Rf.sup.50 and
Rf.sup.51 are the same or different and each is a perfluoroalkyl
group having 1 to 20 carbon atoms; X.sup.10 and X.sup.11 are the
same or different and each is H, F, an alkyl group having 1 to 20
carbon atoms or a fluorine-containing alkyl group which has 1 to 20
carbon atoms and may have ether bond; X.sup.12 is hydrogen atom,
fluorine atom, an alkyl group having 1 to 20 carbon atoms, a
fluorine-containing alkyl group which has 1 to 20 carbon atoms and
may have ether bond, OH group or a group represented by the
formula: ##STR14## wherein Rf.sup.52 and Rf.sup.53 are the same or
different and each is a perfluoroalkyl group having 1 to 20 carbon
atoms; R.sup.50 is at least one selected from an alkylene group or
fluorine-containing alkylene group which has 1 to 3 carbon atoms
and constitutes a ring; R.sup.51 and R.sup.52 are the same or
different and each is at least one selected from a divalent
hydrocarbon group which has 1 to 7 carbon atoms and constitutes a
ring, oxygen atom, a divalent hydrocarbon group having ether bond
which has the sum of oxygen atoms and carbon atoms of 2 to 7 and
constitutes a ring, a divalent fluorine-containing alkylene group
which has 1 to 7 carbon atoms and constitutes a ring or a divalent
fluorine-containing alkylene group having ether bond which has the
sum of oxygen atoms and carbon atoms of 2 to 7 and constitutes a
ring; the sum of carbon atoms constituting a trunk chain in
R.sup.51 and R.sup.52 is not more than 7, and OH group or a group
represented by the formula: ##STR15## wherein Rf.sup.52 and
Rf.sup.23 are as defined above, may be bonded to any of carbon
atoms in R.sup.51; R.sup.53 and R.sup.54 are the same or different
and each is a divalent alkylene group having 1 or 2 carbon atoms or
a divalent fluorine-containing alkylene group having 1 or 2 carbon
atoms; n50, n51, n52, n53 and n54 are the same or different and
each is 0 or 1, N3-1 is a structural unit derived from a monomer
copolymerizable with the monomer to introduce the structural unit
M3-1, and the structural units M3-1 and N3-1 are contained in
amounts of from 0.1 to 100% by mole and from 0 to 99.9% by mole,
respectively.
[0046] The ninth of the present invention relates to a
fluorine-containing polymer having a number average molecular
weight of from 500 to 1,000,000 which is represented by the formula
(61): -(M3-1)-(N-3-1)- (61) in which M3-1 is a structural unit
represented by the formula (54): ##STR16## wherein Rf.sup.50 is a
perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.10 and
X.sup.11 are the same or different and each is H, F, an alkyl group
having 1 to 20 carbon atoms or a fluorine-containing alkyl group
which has 1 to 20 carbon atoms and may have ether bond; R.sup.50 is
at least one selected from an alkylene group or fluorine-containing
alkylene group which has 1 to 3 carbon atoms and constitutes a
ring; R.sup.51 and R.sup.52 are the same or different and each is
at least one selected from a divalent hydrocarbon group which has 1
to 7 carbon atoms and constitutes a ring, oxygen atom, a divalent
hydrocarbon group having ether bond which has the sum of oxygen
atoms and carbon atoms of 2 to 7 and constitutes a ring, a divalent
fluorine-containing alkylene group which has 1 to 7 carbon atoms
and constitutes a ring or a divalent fluorine-containing alkylene
group having ether bond which has the sum of oxygen atoms and
carbon atoms of 2 to 7 and constitutes a ring; the sum of carbon
atoms constituting a trunk chain in R.sup.51 and R.sup.52 is not
more than 7, and OH group or a group represented by the formula:
##STR17## wherein Rf.sup.52 and Rf.sup.53 are the same or different
and each is a perfluoroalkyl group having 1 to 20 carbon atoms, may
be bonded to any of carbon atoms in R.sup.51; R.sup.53 and R.sup.54
are the same or different and each is a divalent alkylene group
having 1 or 2 carbon atoms or a divalent fluorine-containing
alkylene group having 1 or 2 carbon atoms; n50, n51, n52, n53 and
n54 are the same or different and each is 0 or 1, N3-1 is a
structural unit derived from a monomer copolymerizable with the
monomer to introduce the structural unit M3-1, and the structural
units M3-1 and N3-1 are contained in amounts of from 0.1 to 100% by
mole and from 0 to 99.9% by mole, respectively.
[0047] It is preferable that in the formula (53), X.sup.12 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms, or that in R.sup.51 or R.sup.52 of the formula (54), at
least one of fluorine atom or a perfluoroalkyl group having 1 to 20
carbon atoms is bonded to at least one of neighboring carbon atoms
of the carbon atom bonded to OH group.
[0048] Further in the formula (54), also preferred is a structural
unit having, in the structure of R.sup.51, at least one structural
unit represented by the formula: ##STR18## wherein Rf.sup.52 is as
defined above.
[0049] Further it is preferable that the above-mentioned structural
unit M3-1 is a structural unit satisfying the above-mentioned
Equation 1 and further Equation 2.
[0050] The tenth of the present invention relates to a
fluorine-containing cyclopentene having OH group which is
represented by the formula (70): ##STR19## wherein Rf.sup.70 is a
perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.70 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms; X.sup.71 is hydrogen atom, fluorine atom, a hydrocarbon
group having 1 to 20 carbon atoms or a perfluoroalkyl group having
1 to 20 carbon atoms; X.sup.72 is hydrogen atom, fluorine atom, OH
group, a hydrocarbon group having 1 to 20 carbon atoms or a
perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.73 is
hydrogen atom, fluorine atom, a hydrocarbon group having 1 to 20
carbon atoms or a perfluoroalkyl group having 1 to 20 carbon atoms;
when X.sup.72 is OH group, X.sup.73 is not fluorine atom.
[0051] In the above-mentioned formula (70), it is preferable that
both of X.sup.70 and X.sup.71 are fluorine atoms or perfluoroalkyl
groups having 1 to 20 carbon atoms or X.sup.72 is OH group and
X.sup.73 is a perfluoroalkyl group having 1 to 20 carbon atoms.
BRIEF DESCRIPTION OF THE DRAWING
[0052] FIG. 1 is a graph in which .DELTA.H and pKa calculated in
Experimental Example 1 are plotted.
DETAILED DESCRIPTION
[0053] First, the first novel fluorine-containing polymer of the
present invention is explained below.
[0054] The first novel fluorine-containing polymer is, as mentioned
above, a fluorine-containing polymer having an aliphatic monocyclic
structure in the polymer trunk chain which has a number average
molecular weight of from 500 to 1,000,000 and is represented by the
formula (Ma): -(M1)-(M2a)-(N)- (Ma) in which the structural unit M1
is a structural unit derived from an ethylenic monomer having 2 or
3 carbon atoms and at least one fluorine atom, the structural unit
M2a is at least one structural unit which introduces an aliphatic
monocyclic structure in the polymer trunk chain and is represented
by the formula (a): ##STR20## wherein R.sup.1 is at least one
hydrocarbon group selected from the group consisting of a divalent
hydrocarbon group which has 1 to 8 carbon atoms and constitutes a
ring (which may be further substituted with a hydrocarbon group or
a fluorine-containing alkyl group) and a divalent hydrocarbon group
having ether bond which has the sum of carbon atoms and oxygen
atoms of 2 to 8 and constitutes a ring (which may be further
substituted with a hydrocarbon group or a fluorine-containing alkyl
group); R.sup.2 is an alkylene group which has 1 to 3 carbon atoms
and constitutes a ring; R.sup.3 and R.sup.4 are the same or
different and each is a divalent alkylene group having 1 or 2
carbon atoms; n1, n2 and n3 are the same or different and each is 0
or 1, the structural unit N is a structural unit derived from a
monomer copolymerizable with the monomers to introduce the
structural units M1 and M2a, and the structural units M1, M2a and N
are contained in amounts of from 1 to 99% by mole, from 1 to 99% by
mole and from 0 to 98% by mole, respectively.
[0055] In the structural unit M2a introducing the monocyclic
structure, the divalent hydrocarbon groups R.sup.1 and R.sup.2
constitute a ring, and two neighboring carbon atoms of the divalent
hydrocarbon group R.sup.1 may be bonded to each other without
R.sup.2.
[0056] The divalent hydrocarbon group R.sup.1 in the structural
unit M2a is a divalent hydrocarbon group which constitutes a ring
and has 1 to 8 carbon atoms, and hydrogen atom thereof may be
substituted with a hydrocarbon group (for example, a hydrocarbon
group having 1 to 20 carbon atoms, preferably an alkyl group having
1 to 5 carbon atoms) or a fluorine-containing alkyl group (for
example, a fluorine-containing alkyl group which has 1 to 20 carbon
atoms and may have ether bond, preferably a fluorine-containing
alkyl group which has 1 to 5 carbon atoms and may have ether bond
or a perfluoroalkyl group which may have ether bond). R.sup.1 may
have an unsaturated bond.
[0057] The divalent hydrocarbon group R.sup.1 may have ether bond,
and in that case, is a group which has the sum of carbon atoms and
oxygen atoms of from 2 to 8 and constitutes a ring. Hydrogen atoms
of R.sup.1 also may be substituted with hydrocarbon groups or
fluorine-containing alkyl groups similar to those mentioned above,
and R.sup.1 may have an unsaturated bond.
[0058] In the first fluorine-containing polymer of the present
invention, the structural unit M2a constituting a ring does not
have functional group.
[0059] Examples of preferred structural unit M2a are structural
units derived from unsaturated aliphatic monocyclic compounds such
as: ##STR21## The structural unit M2a encompasses those in which
hydrogen atoms other than the hydrogen atoms bonded to the carbon
atoms of carbon-carbon double bond are substituted with a
hydrocarbon group (for example, a hydrocarbon group having 1 to 20
carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms)
or a fluorine-containing alkyl group (for example, a
fluorine-containing alkyl group which has 1 to 20 carbon atoms and
may have ether bond, preferably a fluorine-containing alkyl group
which has 1 to 5 carbon atoms and may have ether bond or a
perfluoroalkyl group which may have ether bond).
[0060] Among them, preferred are unsaturated compounds constituting
a three-membered ring (in the formula (a), any of n1, n2 and n3 are
0 and the number of carbon atoms of R.sup.1 constituting a ring is
1), five-membered ring (in the formula (a), any of n1, n2 and n3
are 0 and the number of carbon atoms of R.sup.1 constituting a ring
is 3) or eight-membered ring (in the formula (a), any of n1, n2 and
n3 are 0 and the number of carbon atoms of R.sup.1 constituting a
ring is 6) from the viewpoint of good copolymerizability with
fluoroolefins, and particularly preferred are three-membered ring
and eight-membered ring.
[0061] More concretely it is preferable that the structural unit
M2a is a structural unit represented by the formula (a-1):
##STR22## wherein R.sup.6 is selected from hydrogen atom, an alkyl
group having 1 to 5 carbon atoms or a fluorine-containing alkyl
group which has 1 to 5 carbon atoms and may have ether bond; n6 is
0 or an integer of from 1 to 12, or the formula (a-2): ##STR23##
wherein R.sup.7 and R.sup.8 are the same or different and each is
hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a
fluorine-containing alkyl group which has 1 to 5 carbon atoms and
may have ether bond.
[0062] The second novel fluorine-containing polymer of the present
invention is, as mentioned above, a fluorine-containing polymer
having an aliphatic monocyclic structure in the polymer trunk chain
which has a number average molecular weight of from 500 to
1,000,000 and is represented by the formula (Mb): -(M1)-(M2b)-(N)-
(Mb) in which the structural units M1 and N are as defined in the
above-mentioned formula (Ma), the structural unit M2b is at least
one structural unit which introduces an aliphatic monocyclic
structure in the polymer trunk chain and is represented by the
formula (b): ##STR24## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4,
n1, n2 and n3 are as defined in the above-mentioned formula (a); Z
are the same or different and each is: ##STR25## wherein Z.sup.1 is
at least one functional group selected from the group consisting of
OH group, COOH group, a derivative of carboxylic acid group and a
functional group protected by a protective group which can convert
the functional group to OH group by reaction with an acid; R.sup.5
is a divalent organic group; n5 is 0 or 1; n4 is an integer of from
1 to 3, and the structural units M1, M2b and N are contained in
amounts of from 1 to 99% by mole, from 1 to 99% by mole and from 0
to 98% by mole, respectively.
[0063] Those fluorine-containing polymers have a moiety Z having
functional group which is introduced to carbon atom constituting a
ring structure equal to the ring structure of the above-mentioned
structural unit M2a having a ring structure, and photosensitivity
necessary for resist application and various useful functions for
other applications can be imparted to the polymer.
[0064] Particularly in the resist application, it is preferable to
introduce the functional group directly to the ring structure
because a polymer having excellent dry etching resistance and
transparency can be obtained.
[0065] The moiety Z having functional group is represented by the
formula: ##STR26## and the functional group Z.sup.1 is at least one
functional group selected from the group consisting of OH group,
COOH group, a derivative of carboxylic acid group and a functional
group protected by a protective group which can convert the
functional group to OH group by reaction with an acid.
[0066] Among them, the derivative of carboxylic acid group is
selected from carboxylic acid esters, functional groups protected
by a protective group which can convert the functional group to
COOH group due to reaction with an acid, carboxylic acid halides
and acid amides. Preferred are carboxylic acid esters and
functional groups protected by a protective group which can convert
the functional group to COOH group due to reaction with an acid.
The derivative of carboxylic acid group is selected, for example,
from --COOR.sup.10, wherein R.sup.10 is an alkyl group having 1 to
10 carbon atoms or --COO--P group mentioned infra.
[0067] The functional group (abbreviated to --COO--P) protecting
the above-mentioned functional group with a protective group (--P)
which can convert the functional group to COOH group due to
reaction with an acid is a functional group necessary, for example,
for the use in positive type resist application, and has a function
that the protective group (--P) is released due to reaction with an
acid generated from a photoacid generator and converts the
functional group to COOH group, thereby making a polymer soluble in
an alkali developing solution though the whole polymer is insoluble
in an alkali developing solution due to action of the protective
group before the reaction with an acid.
[0068] Examples of the functional group (--COO--P) having a
protective group which converts the functional group to COOH group
due to reaction with an acid are: ##STR27## and the like, wherein
R.sup.25, R.sup.26, R.sup.27, R.sup.28, R.sup.29, R.sup.30,
R.sup.31, R.sup.32, R.sup.36, R.sup.37 and R.sup.38 are the same or
different and each is a hydrocarbon group having 1 to 10 carbon
atoms; R.sup.33 and R.sup.34 are the same or different and each is
H or a hydrocarbon group having 1 to 10 carbon atoms; R.sup.35 is a
divalent hydrocarbon group having 2 to 10 carbon atoms. More
concretely there are preferably: ##STR28## and the like, wherein
R.sup.32 is as defined above.
[0069] The functional group (abbreviated to --O--P) protecting the
above-mentioned functional group with a protective group (--P)
which can convert the functional group to --OH group due to
reaction with an acid is a functional group necessary, for example,
for the use in positive type resist application, and has a function
that the protective group (--P) is released due to reaction with an
acid generated from a photoacid generator and converts the
functional group to OH group, thereby making a polymer soluble in
an alkali developing solution though the whole polymer is insoluble
in an alkali developing solution due to action of the protective
group before the reaction with an acid.
[0070] Examples of the functional group (--O--P) having a
protective group which converts the functional group to --OH group
due to reaction with an acid are preferably groups represented by:
##STR29## wherein R.sup.21, R.sup.22, R.sup.23 and R.sup.24 are the
same or different and each is an alkyl group having 1 to 5 carbon
atoms. More concretely there are preferably: ##STR30## and among
them, from the viewpoint of good reactivity with an acid, preferred
are: ##STR31## and further from the viewpoint of good transparency,
preferred are --OC(CH.sub.3).sub.3, --OCH.sub.2OCH.sub.3 and
--OCH.sub.2OC.sub.2H.sub.5.
[0071] The moiety Z having functional group may have R.sup.5, or
the moiety Z may not have R.sup.5 and the functional group Z.sup.1
may be bonded directly to the ring structure.
[0072] When the moiety Z have R.sup.5, R.sup.5 may be one selected
from divalent organic groups. Examples thereof are preferably a
divalent hydrocarbon group which has 1 to 30 carbon atoms and may
have ether bond and a fluorine-containing divalent alkylene group
having 1 to 30 carbon atoms and ether bond.
[0073] Examples of preferred moiety Z having functional group are
those represented by the formula: --(R.sup.9).sub.n7--COOR.sup.10,
wherein R.sup.9 is an alkylene group which has 1 to 10 carbon atoms
and may have ether bond or a fluorine-containing alkylene group
which has 1 to 10 carbon atoms and may have ether bond; R.sup.10 is
hydrogen atom or an alkyl group having 1 to 10 carbon atoms; n7 is
0 or 1. More concretely there are: --COOR.sup.10,
--CH.sub.2COOR.sup.10, --CH.sub.2CH.sub.2COOR.sup.10,
--CH.sub.2CH(CH.sub.3)COOR.sup.10, --CF.sub.2COOR.sup.10,
--CF.sub.2CF.sub.2COOR.sup.10,
--CH.sub.2CH.sub.2CF.sub.2CF.sub.2COOR.sup.10,
--OCH.sub.2COOR.sup.10 and the like.
[0074] Also Z is preferably an alcohol structure represented by the
formula: ##STR32## wherein R.sup.11 is an alkylene group which has
1 to 5 carbon atoms and may have ether bond or a
fluorine-containing alkylene group which has 1 to 5 carbon atoms
and may have ether bond; R.sup.12 and R.sup.13 are the same or
different and each is hydrogen atom, an alkyl group having 1 to 10
carbon atoms, an aryl group having 3 to 10 carbon atoms, a
fluorine-containing alkyl group which has 1 to 10 carbon atoms and
may have ether bond or a fluorine-containing aryl group which has 3
to 10 carbon atoms and may have ether bond; n8 is 0 or 1. Among
them, preferred is a structure having fluorine atom, for example, a
structure represented by the formula: ##STR33## wherein Rf.sup.1 is
a fluorine-containing alkyl group which has 1 to 10 carbon atoms
and may have ether bond; Rf.sup.2 is hydrogen atom, an alkyl 25
group having 1 to 10 carbon atoms, an aryl group having 3 to 10
carbon atoms or a fluorine-containing alkyl group which has 1 to 10
carbon atoms and may have ether bond; n9 is 0 or an integer of from
1 to 5; n10 is 0 or 1, from the viewpoint of transparency and
solubility in a developing solution iii the case of resist
application.
[0075] In the above-mentioned fluorine-containing alcohol
structure, it is further preferable that Rf.sup.1 and Rf.sup.2 are
the same or different and each is a perfluoroalkyl group having 1
to 5 carbon atoms, from the viewpoint of transparency and
solubility in a developing solution.
[0076] Examples of preferred alcohol structure are: ##STR34## and
the like.
[0077] In the second fluorine-containing polymer of the present
invention, example of preferred structural unit M2b forming a ring
is a structural unit represented by the formula (b-1): ##STR35##
wherein Z and n4 are as defined in the formula (b), and examples of
the moiety having functional group are the same as those preferably
exemplified supra.
[0078] Also the present inventors have found that when a specific
diallyl compound having functional group is subjected to cyclic
copolymerization with a fluoroolefin, a fluorine-containing
copolymer having a monocyclic structure in the polymer trunk chain
can be obtained.
[0079] Thereby structural units represented by the formula (b-2):
##STR36## and/or the formula (b-3): ##STR37## wherein Z and n4 are
as defined above, can be obtained.
[0080] Concretely when, for example, a diallyl compound represented
by: ##STR38## wherein Z.sup.5 is the same as the above-mentioned Z
and Z.sup.6 is H or is the same as the above-mentioned Z, is
subjected to cyclic copolymerization with a fluoroolefin,
structural units represented by the formula (b-4): ##STR39## and/or
the formula (b-5): ##STR40## wherein Z.sup.5 and Z.sup.6 are as
defined above, can be obtained.
[0081] In the above-mentioned formulae (b-4) and (b-5), it is
preferable from the viewpoint of copolymerizability that Z.sup.5
and Z.sup.6 are the same or different and each is at least one
selected from COOH or a derivative of carboxylic acid group.
[0082] Example of preferred derivative of carboxylic acid group is
one selected from carboxylic acid esters, functional groups
protected by a protective group which can convert the functional
group to COOH group due to reaction with an acid, acid halides and
acid amides.
[0083] In the fluorine-containing polymer of the present invention,
the structural unit M1 derived from a fluoroolefin is at least one
structural unit selected from structural units derived from
fluorine-containing ethylenic monomers having 2 or 3 carbon atoms.
Examples thereof are, for instance, tetrafluoroethylene,
chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride,
trifluoroethylene, hexafluoropropylene and the like.
[0084] Among them, preferred are structural units derived from
tetrafluoroethylene and chlorotrifluoroethylene because
transparency and dry etching resistance can be improved in resist
application.
[0085] In the polymers of the formulae (Ma) and (Mb) of the present
invention, the structural unit M1, the structural unit M2a or M2b
and the structural unit N are contained in amounts of from 1 to 99%
by mole, from 1 to 99% by mole and from 0 to 98% by mole,
respectively. Provided that (M1)+(M2a) or (M1)+(M2b) is 100% by
mole, a percent by mole ratio of (M1)/(M2a) or (M1)/(M2b) is
preferably 80/20 to 20/80, more preferably 70/30 to 30/70, further
preferably 60/40 to 40/60.
[0086] The present inventors have found that a specific ethylenic
monomer having functional group can be copolymerized in addition to
the fluoroolefin and the above-mentioned monomer being capable of
introducing a monocyclic structure, thereby making it possible to
introduce the functional group to the fluorine-containing polymer
having a monocyclic structure in its trunk chain.
[0087] Accordingly photosensitivity necessary in resist application
and various useful functions necessary in other applications can be
imparted to the polymer.
[0088] The structural unit derived from an ethylenic monomer having
functional group which is copolymerized with the fluoroolefin and
the monomer introducing the monocyclic structure is a structural
unit derived from an ethylenic monomer and represented by the
formula (N-1): ##STR41## wherein X.sup.1 and X.sup.2 are the same
or different and each is H or F; X.sup.3 is H, F, CH.sub.3 or
CF.sub.3; X.sup.4 and X.sup.5 are the same or different and each is
H, F or CF.sub.3; Rf is a fluorine-containing alkylene group having
1 to 40 carbon atoms or a fluorine-containing alkylene group having
2 to 100 carbon atoms and ether bond; a is 0 or an integer of from
1 to 3; b and c are the same or different and each is 0 or 1;
Z.sup.2 is at least one functional group selected from the group
consisting of OH group, COOH group, a derivative of carboxylic acid
group and a functional group protected by a protective group which
can convert the functional group to OH group due to reaction with
an acid.
[0089] Examples thereof are, for instance, as follows. (i)
Structural Unit Derived from Acrylic Monomer and Represented by:
##STR42## wherein X.sup.1 and X.sup.2 are the same or different and
each is H or F; X.sup.3 is H, F, CH.sub.3 or CF.sub.3; R is
selected from hydrogen atom, a hydrocarbon group having 1 to 20
carbon atoms, a fluorine-containing alkyl group having 1 to 20
carbon atoms, a fluorine-containing alkyl group having 2 to 100
carbon atoms and ether bond or a fluorine-containing aryl group
having 3 to 20 carbon atoms.
[0090] In the above-mentioned formula, examples of preferred --R
are: hydrogen atom,
--C(CH.sub.3).sub.3, --CH.sub.2CH.sub.2OH,
--(CH.sub.2).sub.m(CF.sub.2).sub.n--F,
--(CH.sub.2).sub.m(CF.sub.2).sub.n--H,
--(CH.sub.2).sub.m(CF.sub.2).sub.n--Cl,
(m is an integer of from 1 to 5, n is an integer of from 1 to 10)
--CH(CF.sub.3).sub.2, --CH.sub.2CFHCF.sub.3,
--(CH.sub.2).sub.m(CF.sub.2).sub.n--CF(CF.sub.3).sub.2,
[0091] (m is an integer of from 1 to 5, n is an integer of from 1
to 10) ##STR43## and the like.
[0092] Examples thereof are, for instance, acrylic acid,
methacrylic acid, .alpha.-fluoroacrylic acid,
.alpha.-trifluoromethylacrylic acid, acrylic acid esters,
.alpha.-fluoroacrylic acid esters, methacrylic acid esters,
.alpha.-trifluoromethylacrylic acid esters, hydroxyethyl acrylate,
hydroxyethyl methacrylate, glycidyl acrylate, glycidyl
methacrylate, acrylamides, methacrylamides and the like.
[0093] The introduction of the structural unit derived therefrom is
preferred because it is possible to enhance solubility in a
solvent, photosensitivity with a photoacid generator, adhesion to a
substrate and compatibility with a photoacid generator and other
additives.
[0094] It is preferable that at least any one of X.sup.1, X.sup.2
and X.sup.3 has fluorine atom and/or X.sup.3 is a trifluoromethyl
group, from the viewpoint of transparency and dry etching
resistance. It is particularly preferable that X.sup.3 is fluorine
atom or a trifluoromethyl group. (ii)-Structural Unit Derived from
Fluorine-Containing Ethylenic Monomer Having Functional Group and
Represented by: ##STR44## wherein X.sup.1, X.sup.2, X.sup.3,
X.sup.4, a, b, Rf and Z.sup.2 are as defined in the formula (N-1).
Particularly preferred is a structural unit represented by:
##STR45## wherein Rf and Z.sup.2 are as defined in the formula
(N-1).
[0095] Concretely there are preferably structural units derived
from fluorine-containing ethylenic monomers such as: ##STR46## and
the like, wherein Z.sup.2 is as defined in the formula (N-1). Also
preferred is a structural unit represented by the formula:
##STR47## wherein Rf and Z.sup.2 are as defined in the formula
(N-1). Concretely there are preferably structural units derived
from monomers such as: ##STR48## and the like, wherein Z.sup.2 is
as defined in the formula (N-1).
[0096] Examples of the other fluorine-containing ethylenic monomer
having functional group are:
CF.sub.2.dbd.CFCF.sub.2--O--Rf-Z.sup.2,
CF.sub.2.dbd.CF--Rf-Z.sup.2,
CH.sub.2.dbd.CH--Rf-Z.sup.2, CH.dbd.CHO--Rf-Z.sup.2
[0097] and the like, wherein Rf and Z.sup.2 are as defined in the
formula (N-1). More concretely there are: ##STR49## and the like,
wherein Z.sup.2 is as defined in the formula (N-1).
[0098] Examples of the functional group Z.sup.2 contained in the
above-mentioned respective structural units N1 are preferably the
same as the examples of the above-mentioned functional group
Z.sup.1.
[0099] The fluorine-containing polymer of the present invention
having the structural unit N 1 having functional group is
represented by the formula (Ma-1): -(M1)-(M2a)-(N1)-(N)- (Ma-1)
wherein M1 and M2a are as defined in the above-mentioned formula
(Ma) and the structural unit N1 is the same as the formula (N-1).
Examples of preferred structural units M 1, M2a and N1 are the same
as the preferred examples mentioned supra.
[0100] Further the structural unit N1 having functional group may
be introduced to a fluorine-containing polymer having functional
group on the ring, namely, the polymer is represented by the
formula (Mb-1): -(M1)-(M2b)-(N1)-(N)- (Mb-1) wherein M1 and M2b are
as defined in the formula (Mb) and the structural unit N1 is the
same as the formula (N-1). Examples of preferred structural units
M1, M2b and N1 are preferably the same as the preferred examples
mentioned supra. The polymer represented by the formula (Mb-1) is
preferred because functional groups can be introduced in a higher
content and resolution can be improved in the case of use in resist
application.
[0101] With respect to proportions of each structural unit in the
polymers of the formulae (Ma-1) and (Mb-1) of the present
invention, the structural units M1, M2a or M2b, N1 and N are
contained in amounts of from 1 to 98% by mole, from 1 to 98% by
mole, from 1 to 98% by mole and from 0 to 97% by mole,
respectively. It is preferable that when (M1)+(M2a)+(N1) or
(M1)+(M2b)+(N1) is 100% by mole, a percent by mole ratio of
((M1)+(M2a))/(N1) or ((M1)+(M2b))/(N1) is 99/1 to 20/80, more
preferably 95/5 to 30/70, further preferably 90/10 to 40/60.
[0102] In the formulae (Ma), (Mb), (Ma-1) and (Mb-1) of the present
invention, the structural unit N is an optional component
copolymerizable with the other structural units.
[0103] Examples of the optional component are, for instance,
(i) Structural Units Derived from Fluorine-Containing Ethylenic
Monomers (Excluding M1)
[0104] For example, there are preferably structural units derived
from monomers such as: ##STR50## and the like, wherein X is
selected from H, F and Cl, m is from 2 to 10. (ii) Structural Units
Derived from Ethylenic Monomers Having no Fluorine
[0105] The structural units derived from ethylenic monomers having
no fluorine may be introduced to the polymer within a range not
lowering transparency and dry etching resistance (within a range
where the refractive index does not increase).
[0106] The introduction of these structural units is preferred
since adhesion to a substrate is improved, solubility in a
general-purpose solvent is enhanced and compatibility with, for
example, a photoacid generator and additives to be added as case
demands can be improved.
[0107] Examples of the non-fluorine-containing ethylenic monomer
are as follows.
.alpha.-Olefins:
[0108] Ethylene, propylene, butene, vinyl chloride, vinylidene
chloride and the like.
Vinyl Ether or Vinyl Ester Monomers:
[0109] CH.sub.2.dbd.CHOR, CH.sub.2.dbd.CHOCOR (R: hydrocarbon group
having 1 to 20 carbon atoms) and the like.
Allyl Monomers:
[0110] CH.sub.2.dbd.CHCH.sub.2Cl, CH.sub.2.dbd.CHCH.sub.2OH,
CH.sub.2.dbd.CHCH.sub.2COOH, CH.sub.2.dbd.CHCH.sub.2Br and the
like. Allyl Ether Monomers:
[0111] CH.sub.2.dbd.CHCH.sub.2OR
[0112] (R: hydrocarbon group having 1 to 20 carbon atoms),
##STR51## and the like.
[0113] The molecular weight of the fluorine-containing polymers of
the formulae (Ma), (Mb), (Ma-1) and (Mb-1) of the present invention
can be selected in a range of from 500 to 1,000,000 in number
average molecular weight depending on application, purpose and form
in use of the polymer. Preferred molecular weight is from 1,000 to
700,000, more preferably from about 2,000 to about 500,000. When
the molecular weight is too low, heat resistance and mechanical
properties of the obtained polymer coating film easily becomes
insufficient, and a too high molecular weight is apt to be
disadvantageous from the viewpoint of processability. Particularly
in the case of aiming at forming a thin coating film by using the
polymer as a coating material, a too high molecular weight is
disadvantageous from the viewpoint of film forming property. The
molecular weight is preferably not more than 300,000, particularly
preferably not more than 200,000.
[0114] The fluorine-containing polymers of the formulae (Ma), (Mb),
(Ma-1) and (Mb-1) of the present invention can be obtained by
various processes, for example, by copolymerizing, through known
process, monomers corresponding to the respective structural units,
namely, the fluoroolefin (M1), the unsaturated compound having a
monocyclic structure or the diene compound (M2) being capable of
undergoing cyclic polymerization, the ethylenic monomer (N1) having
functional group as case demands and the monomer (N) corresponding
to the optional component. For the polymerization, radical
polymerization method, anion polymerization method, cation
polymerization method and the like can be employed. Among them, the
radical polymerization method is preferably used from the point
that each monomer for obtaining the polymer of the present
invention has good radical polymerizability, control of composition
and molecular weight is easy and production in an industrial scale
is easy.
[0115] Namely, in order to initiate the polymerization, means for
initiation is not limited particularly as far as the polymerization
proceeds radically. The polymerization is initiated, for example,
with an organic or inorganic radical polymerization initiator,
heat, light, ionizing radiation or the like. The polymerization can
be carried out by solution polymerization, bulk polymerization,
suspension polymerization, emulsion polymerization or the like. The
molecular weight is controlled by the contents of monomers to be
used for the polymerization, the content of polymerization
initiator, the content of chain transfer agent, temperature, etc.
The components of the copolymer to be produced can be controlled by
the starting monomer components.
[0116] The second of the present invention relates to a novel
fluorine-containing unsaturated aliphatic monocyclic compound
having functional group.
[0117] The novel fluorine-containing unsaturated cyclic compound of
the present invention is a compound represented by the formula (1):
##STR52## wherein Z.sup.3 are the same or different and each is
--Rf.sup.3-Z.sup.4, in which Z.sup.4 is at least one functional
group selected from the group consisting of OH group, COOH group, a
derivative of carboxylic acid group and a functional group
protected by a protective group which can convert the functional
group to OH group due to reaction with an acid; Rf.sup.3 is a
fluorine-containing alkylene group which has 1 to 30 carbon atoms
and may have ether bond; n11 is an integer of from 1 to 4.
[0118] The compound of the formula (1) of the present invention is
a fluorine-containing unsaturated cyclic compound having functional
group, and the moiety Z.sup.3 having functional group and bonded to
the cyclic structure is characterized by having a
fluorine-containing alkylene group Rf.sup.3, which is preferred
because copolymerizability with fluoroolefins becomes better and
transparency of the obtained fluorine-containing polymer becomes
excellent.
[0119] Examples of preferred functional group Z.sup.4 are the same
as the examples of the functional group Z.sup.1 contained in the
structural unit of the formula (b) in the above-mentioned
fluorine-containing polymer.
[0120] Examples of preferred fluorine-containing alkylene group
Rf.sup.3 are: --(CF.sub.2).sub.n--,
--(CH.sub.2).sub.m--(CF.sub.2).sub.n-- (m and n are integers of
from 1 to 10), ##STR53## and the like.
[0121] The first of the preferred fluorine-containing unsaturated
cyclic compounds of the present invention is represented by the
formula (2): ##STR54## wherein Rf.sup.4 is a perfluoroalkylene
group which has 1 to 10 carbon atoms and may have ether bond;
R.sup.14 is hydrogen atom or an alkyl group having 1 to 10 carbon
atoms; n 1 is as defined in the formula (1). Examples thereof are:
##STR55## and the like.
[0122] Those unsaturated cyclic compounds may be synthesized by any
processes. For example, synthesis can be carried out by the
following process.
[0123] First, a halide X.sup.4--Rf.sup.4--COOR.sup.14, in which
X.sup.4 is selected from bromine or iodine, is reacted at low
temperature directly with a metal such as zinc, magnesium or Li or
with an organometallic compound comprising the above-mentioned
metal such as a Grignard reagent or an alkyl lithium compound, thus
preparing a fluorine-containing alkylation agent
X.sup.4MRf.sup.4--COOR.sup.14, in which X.sup.4 is bromine or
iodine, M is a metal.
[0124] Next, a halide of cyclopentene: ##STR56## wherein X.sup.5 is
selected from chlorine, bromine and iodine, is reacted at low
temperature with the previously prepared fluorine-containing
alkylation agent X.sup.4MRf.sup.4--COOR.sup.14 and thereby a
fluorine-containing cyclopentene compound having carboxylic acid or
derivative of carboxylic acid corresponding thereto can be
obtained.
[0125] The second of the preferred fluorine-containing unsaturated
cyclic compound of the present invention is a cyclopentene compound
having a fluorine-containing alcohol structure which is represented
by the formula (3): ##STR57## wherein R.sup.15 is an alkylene group
which has 1 to 5 carbon atoms and may have ether bond or a
fluorine-containing alkylene group which has 1 to 5 carbon atoms
and may have ether bond; Rf.sup.5 is a fluorine-containing alkyl
group which has 1 to 10 carbon atoms and may have ether bond;
Rf.sup.6 is hydrogen atom, an alkyl group having 1 to 10 carbon
atoms or a fluorine-containing alkyl group which has 1 to 10 carbon
atoms and may have ether bond; n12 is 0 or 1; n 1 is as defined in
the formula (1).
[0126] Particularly preferred is a cyclopentene compound having a
fluorine-containing alcohol structure which is represented by the
formula (4): ##STR58## wherein Rf.sup.5 and Rf.sup.6 are as defined
in the above-mentioned formula; n13 is 0 or an integer of from 1 to
5; n14 is 0 or 1; n 1 is as defined in the formula (1).
[0127] Further it is preferable that Rf.sup.5 and Rf.sup.6 are the
same or different and each is a perfluoroalkyl group having 1 to 5
carbon atoms.
[0128] Those cyclopentene compounds having a fluorine-containing
alcohol structure are particularly useful monomers for resist
application because particularly high transparency can be imparted
to the polymer obtained by copolymerization and solubility in a
developing solution can also be imparted because of high acidity of
OH group.
[0129] Examples of those cyclopentene compounds having a
fluorine-containing alcohol structure are: ##STR59## and the
like.
[0130] Those unsaturated cyclic compounds may be synthesized by any
processes. For example, synthesis can be carried out by the
following process.
[0131] First, a magnesium metal is reacted directly with a halide
of cyclopentene compound: ##STR60## wherein X.sup.5 is selected
from chlorine, bromine and iodine, to synthesize a cyclopentene
magnesium halide (Grignard reagent) and then hexafluoro acetone is
reacted therewith, and thus an unsaturated cyclic compound can be
produced.
[0132] The third of the present invention relates to the
photoresist composition, preferably the chemically amplifying
photoresist composition which comprises a fluorine-containing
aliphatic monocyclic polymer having an acid-reactive group and a
photoacid generator and can be used for a patterning process using
F.sub.2 laser as light source.
[0133] The chemically amplifying photoresist comprises a resin
(polymer) component and a photoacid generator. An acid is generated
from the acid generator at an energy-exposed portion of the resist
and a catalytic action of the acid is used. In the chemically
amplifying positive photoresist, an acid generated at an
energy-exposed portion is scattered by the following heat-treatment
(post exposure bake: hereinafter abbreviated to PEB) to release an
acid-labile or acid-decomposable functional group of the resin and
re-generate an acid, thereby making the energy-exposed portion
soluble in alkali. The chemically amplifying negative photoresist
generally has a functional group being capable of undergoing
condensation reaction by an acid and is alkali-soluble. The
negative photoresist contains a crosslinking agent in addition to
the resin component and acid generator.
[0134] The photoresist composition of the present invention
(preferably chemically amplifying photoresist composition) can be
used as the above-mentioned positive type and negative type
photoresists and comprises:
(A-1) a fluorine-containing polymer having OH group, COOH group
and/or a group which can be dissociated by an acid and converted to
OH group or COOH group,
(B) a photoacid generator and
(C) a solvent,
[0135] in which the fluorine-containing polymer (A-1) is a polymer
comprising a structural unit derived from a fluoroolefin and a
structural unit derived from a monomer introducing an aliphatic
monocyclic structure in the polymer trunk chain, preferably, among
the above-mentioned polymers having an aliphatic monocyclic
structure in the polymer trunk chain, a fluorine-containing polymer
having, as a functional group, OH group, COOH group and/or a
functional group protected by a protective group which can convert
the functional group to OH group or COOH group by reaction with an
acid.
[0136] It has been considered that when a polymer having a
monocyclic structure was used for a resist, dry etching resistance
was insufficient. The present inventors have found that enough dry
etching resistance can be obtained by copolymerizing a structural
unit having a monocyclic structure in its trunk chain with a
fluoroolefin.
[0137] The fluorine-containing polymer (A-1) to be used in the
photoresist composition of the present invention (preferably
chemically amplifying photoresist composition) is selected from
those having a functional group working for a positive or negative
resist among the above-mentioned fluorine-containing polymers
having functional group of the formula (Mb) and/or (Ma-1).
[0138] The functional group working for a resist represents OH
group, COOH group, a functional group (--O--P) protected by a
protective group (--P) which can convert the functional group to OH
group by reaction with an acid or a functional group (--COO--P)
protected by a protective group (--P) which can convert the
functional group to COOH group by reaction with an acid, and at
least one of them is selected.
[0139] Examples of the protected functional groups --O--P and
--COO--P are preferably the same as those described in the
above-mentioned explanation with respect to the functional group of
the fluorine-containing polymer.
[0140] When the fluorine-containing polymer is used for the
photoresist composition (preferably chemically amplifying
photoresist composition), the content of the above-mentioned
functional group in the polymer (when a plurality of functional
groups are used, the sum thereof) varies depending on the polymer
backbone and kind of the functional group and is from 5 to 80% by
mole, preferably from 20 to 70% by mole, more preferably from 30 to
60% by mole based on the whole structural units. When the content
is too low, it is not preferred because solubility in a developing
solution and resolution become insufficient. When the content is
too high, it is not preferred because transparency and dry etching
resistance are lowered.
[0141] The fluorine-containing polymer (A-1) to be used in the
photoresist composition (preferably chemically amplifying
photoresist composition) can be selected from the preferred
examples of the above-mentioned fluorine-containing polymers
(functional group is selected from those mentioned above).
[0142] As a result of further studies by the present inventors, it
was found that a fluorine-containing polymer having a specific
monocyclic structure having hydroxyl (OH) group in trunk chain is
well dissolved in an alkaline developing solution which is used in
a developing step of photoresist process.
[0143] Also it was found that a composition comprising the above
fluorine-containing polymer or the fluorine-containing polymer
having protected OH group and a photoacid generator is useful as a
photoresist composition.
[0144] Namely, the fourth of the present invention relates to a
photoresist composition which comprises:
[0145] (A-2) a fluorine-containing polymer having OH group which
has recurring units of an aliphatic monocyclic structure in the
polymer trunk chain, in which OH group or a moiety having OH group
is bonded to the carbon atom constituting the aliphatic monocyclic
structure,
(B) a photoacid generator and
(C) a solvent,
[0146] in which when in the recurring units of aliphatic monocyclic
structure of the fluorine-containing polymer (A-2), the carbon atom
bonded to OH group is named the first carbon atom and a structure
consisting of the first carbon atom up to the neighboring fourth
carbon atom is assumed to be a model structure, the model structure
having OH group satisfies Equation 1:
.DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH).ltoreq.75 (Equation 1),
preferably Equation 2:
.DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH).ltoreq.70 (Equation 2)
wherein H(M-OH) is a produced enthalpy of the model structure,
H(M-O.sup.-) is a produced enthalpy of the model structure after
dissociation of the OH group and a produced enthalpy of hydrogen
ion is assumed to be a constant of 200 kJ/mol.
[0147] It has been generally said that with respect to a relation
between an acidity and alkali solubility, when an acidity is
increased, namely when an acid dissociation constant pKa is
decreased, alkali solubility becomes high. However, it is not
always said that any of compositions having a smaller pKa have high
solubility in alkali. For example, solubility of a resist in a
developing solution is not determined only by pKa of a OH
group-containing monomer.
[0148] For example, a pKa value of OH group of phenol which is a
representative example of hydrocarbon compound having OH group is
10 and solubility in a developing solution is good. However among
fluorine-containing polymers obtained by copolymerizing a OH
group-containing monomer having a pKa value of about 10, there are
some polymers insoluble in a developing solution.
[0149] As mentioned above, it has been difficult to select a
compound having an optimum solubility in a developing solution only
by a pKa value.
[0150] The present inventors have made another approach to the
above-mentioned problem taking account of produced energy of OH
group before and after the acid dissociation and have found that a
fluorine-containing polymer having OH group which has, in its trunk
chain, recurring units satisfying a specific equation of .DELTA.H
(difference in produced energy) defined above has unexpectedly
excellent solubility in a developing solution. This equation of
.DELTA.H mentioned above was firstly found by the present
inventors.
[0151] Conventional hydrocarbon compounds having OH group have a
pKa value of not less than 12, generally from 14 to 16. However
those hydrocarbon compounds do not have enough correlation between
the above-mentioned difference in produced enthalpy (.DELTA.H) of
OH group before and after the dissociation and the actually
measured pKa value.
[0152] As mentioned above, the present inventors actually measured
pKa values of various fluorine-containing compounds having OH group
and on the other hand, suggested the above-mentioned .DELTA.H. As a
result of investigation with respect to a relation between the
.DELTA.H and the actually measured pKa value, the present inventors
have found that the pKa value of particularly a fluorine-containing
compound having OH group which has a pKa value of not more than 12
has a good proportional relation with the .DELTA.H, and further
have found that a pKa value of OH group of a fluorine-containing
compound having OH group can be conjectured by calculating .DELTA.H
of the compound according to the equation (Equation 1 or Equation
2).
[0153] When paying attention to application as a polymer for a
resist, it is necessary for the polymer to have high solubility in
an alkaline developing solution such as an aqueous solution of
2.38% by weight of tetramethylammonium hydroxide which is generally
used in a developing step. On the other hand, in F2 resist
application, transparency at 157 nm in a vacuum ultraviolet region
is required and the use of carboxyl group and phenolic hydroxyl
group which have been used for conventional resists as a group
soluble in a developing solution is disadvantageous from the
viewpoint of transparency. Therefore, in the polymer structure, it
is necessary to select a structure including OH group and its
neighboring structure which gives high transparency and excellent
solubility in a developing solution.
[0154] Hitherto studies have been made with respect to the use of a
fluorine-containing polymer to which a norbornene backbone having
--C(CF.sub.3).sub.2OH group as a group soluble in a developing
solution is introduced, as a polymer for F2 resist possessing
improved transparency and solubility in a developing solution
(WO00/67072, etc.). However though the OH group of this
fluorine-containing polymer has solubility in a developing solution
by an effect of two CF.sub.3 groups, a dissolving rate of the
polymer itself is insufficient only by the introduction of
--C(CF.sub.3.sub.2 OH.
[0155] The present inventors have studied various
fluorine-containing monomers having OH group and structural units
derived therefrom taking advantage of the above-mentioned relation
between AH and pKa value. As a result, the present inventors
defined a model structure of not only --C(CF.sub.3).sub.2OH portion
but also its neighboring structure and calculated .DELTA.H thereof
and have found that when the .DELTA.H is not more than a specific
value, the polymer possesses good solubility in a developing
solution.
[0156] Based on those new findings, further studies have been made,
and it was found that the fluorine-containing polymer having, in
the polymer trunk chain, recurring units of aliphatic monocyclic
structure having OH group which satisfies the above-mentioned
equation of .DELTA.H (Equation 1 or Equation 2) or the
fluorine-containing polymer having a functional group protecting
the OH group is excellent in solubility in a developing solution
while maintaining excellent transparency as the resist polymer.
[0157] Next, a method of calculating a difference .DELTA.H in
produced energy before and after acid dissociation in the present
invention is explained below.
[0158] First, the aliphatic monocyclic structural unit having OH
group in the polymer is selected. Provided that the carbon atom
bonded to OH group of the aliphatic monocyclic structural unit is
the first carbon atom, attention is paid only to the neighboring
carbon atoms and the carbon atom adjacent to the first carbon atom
is assumed to be the second carbon atom and the carbon atom
adjacent to the second carbon atom is assumed to be the third
carbon atom. A structure up to the fourth carbon atom is selected.
If an atomic valence on the fourth carbon atom is insufficient, a
structure subjected to replacement with hydrogen atom is assumed to
be the model structure. When the number of carbon atoms
constituting the aliphatic monocyclic structural unit is few and
the fourth carbon atom is not present, the aliphatic monocyclic
structural unit is assumed to be a model structure.
[0159] The reason why the structure up to the fourth carbon atom is
assumed to be the model structure is that even if a structure
including the fifth or more carbon atoms which are far from OH is
considered, it does not have an effect greatly on the .DELTA.H
value, and for comparing .DELTA.H, the structure up to the fourth
carbon atom suffices. Also in case of a large model structure,
there arises a problem that a sufficient accuracy is difficult to
obtain by a software of calculation method of molecular orbital
available on the market, which is not preferable.
[0160] If technical problems of the calculation are solved, the
.DELTA.H value of the whole fluorine-containing monomer having the
aliphatic monocyclic structure may be calculated without using the
model structure.
[0161] For example, in the case of a structure which is represented
by the formula: ##STR61## when the carbon atoms are numbered, the
structure is represented by: ##STR62## and the structure including
carbon atoms up to the fourth carbon atom (C.sup.4) constitutes a
ring. A structure having hydrogen atoms bonded to the carbon atoms
(C.sup.3 and C.sup.4) having insufficient atomic valence is used as
the model structure.
[0162] Then the calculation of molecular orbital of the adopted
model structure is first carried out to calculate a produced
enthalpy: H(M-OH) before the acid dissociation.
[0163] Each produced enthalpy is calculated using the
semi-empirical calculation method of molecular orbital: AM1 method
(described in Journal of American Chemical Society, 107, p 3902
(1985) by M. J. S. Dewar, E. G. Zoebisch, E. F. Heary and J. J. P.
Stewart,). In the present invention, the calculation is carried out
using MOPAC calculation software MOPAC97 (software for calculation
of molecular orbital) available from FUJITSU LIMITED which uses CS
Chem3D.RTM. Version 4.0 available from Cambridge Soft
Corporation.
[0164] With respect to the same model structure in which OH has
been dissociated, a produced enthalpy H(M-O.sup.-) after the acid
dissociation is calculated by the same method as above. The
produced enthalpy of hydrogen ion is set at 200 kJ/mol as a
constant.
[0165] The .DELTA.H values of the respective aliphatic monocyclic
structures (model structure) having OH group in the
fluorine-containing polymer are determined unambiguously by the
above-mentioned calculation.
[0166] It is a surprise that the above-mentioned Equation 1 and
Equation 2 can be applied on the fluorine-containing polymer
having, in its trunk chain, a structural unit derived from a
fluorine-containing ethylenic monomer having OH group and also the
fluorine-containing polymer having, in its trunk chain, a
structural unit derived from a fluorine-containing norbornene
derivative.
[0167] In the case of the fluorine-containing polymer prepared by
copolymerizing a fluorine-containing ethylenic monomer having OH
group, the model structure thereof is determined by the following
method.
[0168] Provided that the carbon atom bonded to OH group is the
first carbon atom, attention is paid only to the neighboring carbon
atoms and the carbon atom adjacent to the first carbon atom is
assumed to be the second carbon atom and the carbon atom adjacent
to the second carbon atom is assumed to be the third carbon atom. A
structure up to the third or the fourth carbon atom is selected. If
an atomic valence on the third or the fourth carbon atom is
insufficient, a structure subjected to replacement with hydrogen
atom is assumed to be the model structure.
[0169] The reason why the structure up to the fourth carbon atom at
maximum is assumed to be the model structure is the same as
mentioned above. If technical problems of the calculation are
solved, the .DELTA.H value of the whole fluorine-containing
ethylenic monomer may be calculated without using the model
structure, which is also as mentioned above. However if the number
of fluorine atoms in the structure increases, accuracy of the MOPAC
calculation (explained infra) is lowered. Therefore, when the
number of fluorine atoms in the model structure up to the fourth
carbon is not less than seven, it is preferable that the
calculation is carried out using a structure up to the third carbon
as the model structure.
[0170] For example, in the case of a fluorine-containing ethylenic
monomer having OH group which is represented by the formula:
CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH, when the carbon atoms
are numbered, the monomer is represented by:
C.sup.4H.sub.2.dbd.C.sup.3HC.sup.2H.sub.2C.sup.1(C.sup.2F.sub.3).sub.2OH
and the structure including carbon atoms up to the fourth carbon
atom (C.sup.4) and having six or less fluorine atoms can be used
for the calculation. Therefore the whole molecular structure
CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH is used for the
calculation.
[0171] Also in the case of the following fluorine-containing
ethylenic monomer: ##STR63## when carbon atoms up to the fourth
carbon atom (C.sup.4) are used, the number of fluorine atoms is not
less than seven. Therefore the model structure up to the third
carbon atom (C.sup.3), namely: ##STR64## is used for the
calculation of the structural unit derived from the
fluorine-containing ethylenic monomer having OH group.
[0172] Next, in the case of a fluorine-containing polymer having a
structural unit derived from a fluorine-containing norbornene
derivative in its trunk chain, the model structure is basically
selected according to the same definition as in the aliphatic
monocyclic structural unit.
[0173] For example, in the case of: ##STR65## when carbon atoms up
to the fourth one is used, the model structure of the structural
unit derived from a fluorine-containing norbornene derivative is
represented by: ##STR66## and, the structure subjected to bonding
of hydrogen to the carbon (C.sup.4) due to insufficient atomic
valence can be used as the model structure.
[0174] In this case, too, if technical problems of the calculation
are solved because a percentage of replacement with fluorine atom
is small, the .DELTA.H value of the whole structural unit derived
from a fluorine-containing norbornene derivative may be
calculated.
[0175] The fluorine-containing polymer (A-2) for the photoresist
composition of the present invention has a structural unit having
not more than 75 kJ/mol of the AH value calculated by the
above-mentioned method among the aliphatic monocyclic structures
(model structure) having OH group. This polymer is preferable as a
photoresist being excellent in transparency and being high in
solubility in an aqueous solution (developing solution) of 2.38% by
weight of tetramethylammonium hydroxide in which
fluorine-containing polymers have been said to be hardly
dissolved.
[0176] The .DELTA.H value is preferably not more than 70 kJ/mol,
more preferably not more than 50 kJ/mol. When the .DELTA.H value is
too large, solubility in a developing solution of the polymer
obtained by polymerization becomes insufficient, and at forming a
resist pattern, a sufficient resolution is not obtained, a fine
pattern is not obtained and scum and residue easily remain in the
resist. A lower limit of the .DELTA.H value is -110 kJ/mol,
preferably not less than -65 kJ/mol, more preferably not less than
-40 kJ/mol.
[0177] The photoresist composition of the fifth of the present
invention is a photoresist composition which comprises:
[0178] (A-3) a fluorine-containing polymer having OH group which
has recurring units of an aliphatic monocyclic structure in the
polymer trunk chain, in which OH group or a moiety having OH group
is bonded to the carbon atom constituting the aliphatic monocyclic
structure,
(B) a photoacid generator and
(C) a solvent,
[0179] in which the recurring units of the aliphatic monocyclic
structure of the fluorine-containing polymer (A-3) have a structure
represented by the formula (50): ##STR67## wherein Rf.sup.11 is a
perfluoroalkyl group having 1 to 20 carbon atoms; Z.sup.10 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms.
[0180] The fluorine-containing polymer (A-3) having such a
structure of the formula (50) exhibits better solubility in an
aqueous solution of 2.38% by weight of tetramethylammonium
hydroxide which is generally used as a developing solution for a
resist, because of effects of Rf.sup.11 and in addition, the group
Z.sup.10 bonded to the neighboring carbon atom of the carbon atom
bonded to Rf.sup.11 and therefore, is preferred as a resist
polymer.
[0181] In the structure of the formula (50), Rf.sup.11 is a
perfluoroalkyl group and examples thereof are
[0182] F(CF.sub.2).sub.n1 (n1 is an integer of from 1 to 20),
##STR68##
[0183] (n2 is an integer of from 1 to 6) and ##STR69##
[0184] (n3 and n4 are integers which make the sum of carbon atoms
being not more than 20),
and among them, CF.sub.3, C.sub.2F.sub.5, C.sub.3F.sub.7,
C.sub.4F.sub.9, (CF.sub.3).sub.2CF and the like are preferred.
[0185] In the structure of the formula (50), Z.sup.10 is selected
from fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms. Examples of preferred perfluoroalkyl group are the same as
those of Rf.sup.11, and particularly preferred are F, CF.sub.3 and
C.sub.2F.sub.5.
[0186] The structure of the formula (50) may be present in the form
of a side chain on the aliphatic monocyclic structure constituting
the fluorine-containing polymer (A-3) or in the form of a part of
the ring structure forming the aliphatic monocyclic structure. Also
at least one OH group may be present in one molecule of the
monocyclic structure, and the aliphatic monocyclic structure may
have two or more OH groups.
[0187] Example of the preferred structure of the formula (50) in
the recurring units of aliphatic monocyclic structure of the
fluorine-containing polymer (A-3) is a structure represented by the
formula (51): ##STR70## wherein Rf.sup.11 and Rf.sup.12 are the
same or different and each is a perfluoroalkyl group having 1 to 20
carbon atoms; Z.sup.10 is fluorine atom or a perfluoroalkyl group
having 1 to 20 carbon atoms.
[0188] In the structure of the formula (51), examples of the
Rf.sup.12 are preferably the same as those of the Rf.sup.11.
Rf.sup.11 and Rf.sup.12 may be the same or different.
[0189] Also the structure of the formula (51) may be present in the
form of a side chain on the aliphatic monocyclic structure
constituting the fluorine-containing polymer (A-3) or in the form
of a part of the ring structure forming the aliphatic monocyclic
structure. At least one OH group may be present in one molecule of
the monocyclic structure, and the aliphatic monocyclic structure
may have two or more OH groups.
[0190] Also preferable example of the structure of the formula (50)
in the recurring units of aliphatic monocyclic structure of the
fluorine-containing polymer (A-3) is a structure represented by the
formula (52): ##STR71## wherein Rf.sup.11 is a perfluoroalkyl group
having 1 to 20 carbon atoms; Z.sup.10 and Z.sup.11 are the same or
different and each is fluorine atom or a perfluoroalkyl group
having 1 to 20 carbon atoms.
[0191] In the structure of the formula (52), examples of the
Z.sup.11 are preferably the same as those of the above-mentioned
Z.sup.10. Z.sup.10 and Z.sup.11 may be the same or different.
[0192] Also the structure of the formula (52) may be present in the
form of a side chain on the aliphatic monocyclic structure
constituting the fluorine-containing polymer (A-3) or in the form
of a part of the ring structure forming the aliphatic monocyclic
structure. At least one OH group may be present in one molecule of
the monocyclic structure, and the aliphatic monocyclic structure
may have two or more OH groups.
[0193] In the fluorine-containing polymer having the structure of
the formula (50), (51) or (52), though the .DELTA.H value of the
structure may exceed 75 kJ/mol, many structural units having the
.DELTA.H value of not more than 75 kJ/mol are contained in the
polymer and as a matter of course, the .DELTA.H value of the
polymer is preferably not more than 75 kJ/mol, more preferably not
more than 70 kJ/mol, particularly preferably not more than 50
kJ/mol.
[0194] Example of the preferred structure of the recurring unit of
the aliphatic monocyclic structure contained in the
fluorine-containing polymer which is used for the photoresist
composition of the present invention is the structural unit of the
formula (53): ##STR72## wherein Rf.sup.50 and Rf.sup.51 are the
same or different and each is a perfluoroalkyl group having 1 to 20
carbon atoms; X.sup.10 and X.sup.11 are the same or different and
each is H, F, an alkyl group having 1 to 20 carbon atoms,
preferably 1 to 5 carbon atoms or a fluorine-containing alkyl group
which has 1 to 20 carbon atoms, preferably 1 to 5 carbon atoms and
may have ether bond; X.sup.12 is hydrogen atom, fluorine atom, an
alkyl group having 1 to 20 carbon atoms, a fluorine-containing
alkyl group which has 1 to 20 carbon atoms and may have ether bond,
OH group or a group represented by the formula: ##STR73## wherein
Rf.sup.52 and Rf.sup.53 are the same or different and each is a
perfluoroalkyl group having 1 to 20 carbon atoms; R.sup.50 is at
least one selected from an alkylene group or fluorine-containing
alkylene group which has 1 to 3 carbon atoms and constitutes a
ring; R.sup.51 and R.sup.52 are the same or different and each is
at least one selected from a divalent hydrocarbon group which has 1
to 7 carbon atoms and constitutes a ring, oxygen atom, a divalent
hydrocarbon group having ether bond which has the sum of oxygen
atoms and carbon atoms of 2 to 7 and constitutes a ring, a divalent
fluorine-containing alkylene group which has 1 to 7 carbon atoms
and constitutes a ring or a divalent fluorine-containing alkylene
group having ether bond which has the sum of oxygen atoms and
carbon atoms of 2 to 7 and constitutes a ring; and the sum of
carbon atoms constituting a trunk chain in R.sup.51 and R.sup.52 is
not more than 7, and OH group or a group represented by the
formula: ##STR74## wherein Rf.sup.52 and Rf.sup.53 are as defined
above, may be bonded to any of carbon atoms in R.sup.51; R.sup.53
and R.sup.54 are the same or different and each is a divalent
alkylene group having 1 or 2 carbon atoms or a divalent
fluorine-containing alkylene group having 1 or 2 carbon atoms; n50,
n51, n52, n53 and n54 are the same or different and each is 0 or 1,
or the structural unit represented by the formula (54): ##STR75##
wherein Rf.sup.50, X.sup.10, X.sup.11, R.sup.50, R.sup.51,
R.sup.52, R.sup.53, R.sup.54, n50, n51, n52, n53 and n54 are as
defined in the above-mentioned formula (53). The
fluorine-containing polymer having the structural unit (53) or (54)
is referred to as (A-5).
[0195] Also it is preferable that the structural unit (53) or (54)
contains any of the above-mentioned structures of the formula (50),
(51) and (52).
[0196] Concretely it is preferable that X.sup.12 in the formula
(53) is Z.sup.10 in the formula (51), wherein Z.sup.10 is fluorine
atom or a perfluoroalkyl group having 1 to 20 carbon atoms.
[0197] It is preferable that at least one Z.sup.10 of the formula
(50), wherein Z.sup.10 is fluorine atom or a perfluoroalkyl group
having 1 to 20 carbon atoms, is bonded to any one of neighboring
carbon atoms of the carbon atom bonded to OH group of the formula
(54) or it is preferable that one or two of Z.sup.10 and of
Z.sup.11 of the formula (52), wherein Z.sup.10 and Z.sup.11 are the
same or different and each is fluorine atom or a perfluoroalkyl
group having 1 to 20 carbon atoms, are bonded to both neighboring
carbon atoms of the carbon atom bonded to OH group of the formula
(54).
[0198] Those fluorine-containing polymers having recurring unit of
monocyclic structure represented by the formula (53) or (54) are
novel substances which have not been disclosed in prior literatures
and patent publications. Also the above-mentioned preferred
structural units of the formula (53) and (54) are novel substances
which have not been disclosed in prior literatures and patent
publications.
[0199] More concretely examples thereof are those mentioned below,
and calculated .DELTA.H values of some of them are also mentioned
below. ##STR76##
[0200] Also in the photoresist composition of the present
invention, two or more OH groups or moieties having OH group may be
bonded in the aliphatic monocyclic structure having OH group. For
example, preferred is the monocyclic structure of the formula (53),
in which a group: ##STR77## wherein Rf.sup.52 and Rf.sup.53 are the
same or different and each is a perfluoroalkyl group having 1 to 20
carbon atoms, is bonded instead of X.sup.12, and/or at least one
group: ##STR78## wherein R.sup.52 and R.sup.53 are as defined
above, is bonded to any of carbon atoms of R.sup.51 (in case where
n51 is 1). Also preferred is the monocyclic structural unit of the
formula (54), in which OH group is bonded to any of carbon atoms of
R.sup.51 (in case where n51 is 1) and/or at least one structural
unit: ##STR79## wherein R.sup.52 is as defined above, is contained
in the structure of R.sup.51 (in case where n51 is 1).
[0201] Examples thereof are: ##STR80## and the like. It is
preferable that the fluorine-containing polymer has those
structural units. The fluorine-containing polymers having recurring
units of those monocyclic structures are novel substances which
have not been disclosed in any of literatures and patent
publications.
[0202] Among them, a monomer: ##STR81## which can introduce a
structural unit: ##STR82## is also a novel compound. Example of a
preparation process thereof is as shown in the following
preparation scheme (1). ##STR83##
[0203] Also a monomer: ##STR84## which can introduce a structural
unit: ##STR85## is a novel compound. Example of a preparation
process thereof is as shown in the following preparation scheme
(2). ##STR86##
[0204] Also a monomer: ##STR87## which can introduce a structural
unit: ##STR88## is a novel compound. Example of a preparation
process thereof is as shown in the following preparation scheme
(3). ##STR89## (MEC-31 is a fluorinating agent available from
DAIKIN INDUSTRIES, LTD.)
[0205] Also a monomer represented by: ##STR90## which can introduce
a structural unit represented by: ##STR91## is a novel compound,
and example of a preparation process thereof is the following
preparation scheme (4). ##STR92##
[0206] Also a structural unit represented by: ##STR93## can be
obtained by cyclic polymerization of a diene compound represented
by: ##STR94## and further can be obtained by (co)polymerization of
a novel monomer represented by: ##STR95## and example of a
preparation process thereof is the following preparation scheme
(5). ##STR96##
[0207] It is preferable that the fluorine-containing polymer having
OH group for the photoresist composition of the present invention
has at least one of the aliphatic monocyclic structure satisfying
the above-mentioned Equation 1, aliphatic monocyclic structures
having the structures of the formulae (50) to (52) or the
monocyclic structures of the formula (53) to (54) (which are
generically referred to as "structural unit M3"). The
fluorine-containing polymer is a homopolymer consisting of the
structural unit M3 of monocyclic structure having OH group or a
copolymer comprising the structural unit M3 and a structural unit
copolymerizable therewith (the above-mentioned M1, N, etc.).
Concretely it is preferable that the fluorine-containing polymer is
a fluorine-containing polymer having a number average molecular
weight of from 500 to 1,000;000 which is represented by the formula
(60): -(M3)-(N3)- (60) wherein M3 is at least one recurring unit
selected from recurring units of the aliphatic monocyclic structure
satisfying the above-mentioned Equation 1 or 2, aliphatic
monocyclic structures having the structures of the formula (50) to
(52) or the monocyclic structures of the formula (53) to (54); N3
is a structural unit derived from a monomer copolymerizable with
the monomer to introduce the structural unit M3, and the structural
units M3 and N3 are contained in amounts of from 0.1 to 100% by
mole and from 0 to 99.9% by mole, respectively.
[0208] Particularly the fluorine-containing polymer having the
recurring unit selected from the monocyclic structures of the
formula (53) to (54) is a novel substance which has not been
disclosed in literatures and patent publications.
[0209] Namely, the novel fluorine-containing polymer of the present
invention is a fluorine-containing polymer having a number average
molecular weight of from 500 to 1,000,000 which is represented by
the formula (61): (M3-1)-(N-3-1)- (61) wherein M3-1 is at least one
structural unit selected from the monocyclic structural units of
the formulae (53) and (54); N3-1 is a structural unit derived from
a monomer copolymerizable with the monomer to introduce the
structural unit M3-1, and the structural units M3-1 and N3-1 are
contained in amounts of from 0.1 to 100% by mole and from 0 to
99.9% by mole, respectively.
[0210] Examples of the structural unit M3-1 of the
fluorine-containing polymer of the present invention are the same
as those mentioned above as preferred examples of the formulae (53)
and (54).
[0211] In the formulae (60) and (61), the copolymerizable
components N3 and N3-1 are optional components and are not
particularly limited as far as they are monomers copolymerizable
with the structural units M3 and M3-1. The structural units N3 and
N3-1 may be optionally selected depending on required
characteristics of intended fluorine-containing polymer.
[0212] It is particularly preferable that the structural unit N3 or
N3-1 is the structural unit M1 in the above-mentioned novel
fluorine-containing polymer (Ma) (the structural unit derived from
an ethylenic monomer having 2 or 3 carbon atoms and at least one
fluorine atom), and examples thereof are preferably the same as the
above-mentioned preferred examples of the structural unit M1. When
those structural units are used, a polymer which has excellent
transparency and dry etching resistance and is preferred as a
photoresist polymer can be obtained.
[0213] Examples of the structural unit N3 are preferably the same
as the above-mentioned examples of the structural units N and N1
(examples mentioned in (i) and (ii) of the structural unit N and
examples of N1) explained in the first of the present invention
(fluorine-containing polymer having an aliphatic monocyclic
structure in its trunk chain).
[0214] In the fluorine-containing polymer of the present invention
(fluorine-containing polymer used for a photoresist composition),
various combinations and proportions of the structural unit M3 or
M3-1 and the structural unit N3 or N3-1 can be selected from the
above-mentioned examples depending on intended application,
physical properties (particularly glass transition point, hardness,
etc.), functions (transparency, refractive index), etc.
[0215] One of the fluorine-containing polymers of the present
invention (fluorine-containing polymers used for a photoresist
composition) contains the structural unit M3 or M3-1 as an
essential component and has functions due to the structural unit M3
or M3-1 itself such as maintaining a low refractive index and
imparting transparency to the polymer, and functions due to
hydroxyl such as imparting solubility in a solvent, solubility in
an aqueous alkaline solution (developing solution), adhesion to a
substrate and crosslinkability because OH group and fluorine atom
can be introduced to the cyclic structural unit. In addition, dry
etching resistance also becomes good because of the cyclic
structural unit. Therefore even if the fluorine-containing polymer
of the present invention contains a larger amount of the structural
unit M3 or M3-1 or in the extreme case, even if the polymer
consists of the structural unit M3 or M3-1 (100% by mole),
transparency and the dry etching resistance can be maintained.
[0216] Further in the case of the copolymer of the present
invention comprising the structural unit M3 or M3-1 and the
structural unit N3 or N3-1 of a copolymerizable monomer, when the
structural unit N3 or N3-1 is selected from the above-mentioned
examples, a fluorine-containing polymer having a higher glass
transition point, a higher transparency (particularly in a vacuum
ultraviolet region) and a higher dry etching resistance can be
obtained.
[0217] In the copolymer comprising the structural unit M3 or M3-1
and the structural unit N3 or N3-1, the proportion of the
structural unit M3 or M3-1 may be not less than 0.1% by mole based
on the whole monomers constituting the fluorine-containing polymer.
In order to impart solubility in an alkaline solution (developing
solution) to the fluorine-containing polymer, it is preferable that
the structural unit M3 or M3-1 is contained in an amount of not
less than 10% by mole, preferably not less than 20% by mole, more
preferably not less than 30% by mole. An upper limit thereof is
(not more than) 100% by mole.
[0218] The fluorine-containing polymer of the present invention
(fluorine-containing polymer used for a photoresist composition) is
preferable particularly for the resist application since
transparency and dry etching resistance are not lowered even if the
proportion of the structural unit M3 or M3-1 is increased.
[0219] Also in the case of the above-mentioned application
requiring transparency, preferred combinations and proportions of
the structural unit M3 or M3-1 and the structural unit N3 or N3-1
are those which can make the fluorine-containing polymer
non-crystalline.
[0220] The molecular weight of the fluorine-containing polymer of
the present invention (fluorine-containing polymer used for a
photoresist composition) can be selected, for example, within a
range of from 500 to 1,000,000 in number average molecular weight.
Preferred molecular weight is from 1,000 to 500,000, particularly
from 2,000 to 200,000.
[0221] When the molecular weight is too low, mechanical properties
easily become insufficient, and the resist film is apt to be
insufficient in strength. If the molecular weight is too high,
solubility in a solvent is lowered, and film forming property and
leveling property are easily lowered particularly at forming a thin
coating film. For coating applications, most preferable number
average molecular weight is selected within a range of from 5,000
to 100,000.
[0222] With respect to transparency, it is preferable that the
polymer is transparent in the case of vacuum ultraviolet light
having a wavelength of not more than 200 nm. For example, an
absorption coefficient at 157 nm is not more than 3.0 .mu.m.sup.-1,
preferably not more than 2.0 .mu.m.sup.-1, particularly preferably
not more than 1.0 .mu.m.sup.-1. Such a fluorine-containing polymer
is preferable as a base polymer for a F.sub.2 resist.
[0223] Also it is preferable that the fluorine-containing polymer
is soluble in general-purpose solvents, for example, in at least
one of ketone solvents, acetic acid ester solvents, alcohol
solvents, aromatic solvents, glycol ether solvents or glycol ester
solvents or in a solvent mixture containing at least one of the
above-mentioned general-purpose solvents.
[0224] The fluorine-containing polymer of the present invention
(fluorine-containing polymer used for a photoresist composition)
can be obtained by polymerizing a monomer capable of introducing
the structural unit M3 or M3-1, for example, an unsaturated
compound containing an aliphatic monocyclic structure having OH
group, by cyclic (co)polymerization of an ethylenic diene monomer
having OH group or by (co)polymerizing, through known method, a
monomer capable of introducing the structural unit M3 or M3-1 and a
monomer which is a copolymerizable component as the structural unit
N3 or N3-1. For the polymerization, radical polymerization method,
anion polymerization method, cation polymerization method and the
like can be employed. Among them, the radical polymerization method
is preferably used from the point that each monomer exemplified to
obtain the fluorine-containing polymer having OH group of the
present invention has good radial polymerizability, control of
composition and molecular weight is easy and production in an
industrial scale is easy.
[0225] In order to initiate the radical polymerization, means for
initiation is not limited particularly as far as the polymerization
proceeds radically. The polymerization is initiated, for example,
with an organic or inorganic radical polymerization initiator,
heat, light, ionizing radiation or the like. The polymerization can
be carried out by solution polymerization, bulk polymerization,
suspension polymerization, emulsion polymerization or the like. The
molecular weight is controlled by the contents of monomers to be
used for the polymerization, the content of polymerization
initiator, the content of chain transfer agent, temperature, etc.
The components of the copolymer can be controlled by the starting
monomer components.
[0226] Further in the fluorine-containing polymer which is used for
the photoresist composition of the present invention, a part or the
whole of OH groups may be protected by a protective group which can
undergo conversion to OH group by reaction with an acid. The
protective group undergoes conversion to OH group by an acid
generated from a photoacid generator and thereby the polymer can
work as a positive type resist.
[0227] Namely, the present invention relates to the photoresist
composition which comprises:
(A-4) a fluorine-containing polymer having functional group
protected by a protective group which can convert the functional
group to OH group by reaction with an acid,
(B) a photoacid generator and
(C) a solvent,
[0228] in which the fluorine-containing polymer (A-4) is a
fluorine-containing polymer having functional group comprising OH
group contained in the recurring unit of aliphatic monocyclic
structure of any of the above-mentioned fluorine-containing
polymers (A-2), (A-3) and (A-5) and the protective group protecting
the OH group.
[0229] Examples of the preferred acid-labile group which is used as
a protective group are groups represented by: ##STR97## wherein
R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are the same or different and
each is an alkyl group having 1 to 5 carbon atoms.
[0230] More concretely there are preferably: ##STR98## and from the
viewpoint of good acid-reactivity, preferred are
--OC(CH.sub.3).sub.3, ##STR99## --OCH.sub.2OCH.sub.3 and
--OCH.sub.2OC.sub.2H.sub.5 and from the viewpoint of good
transparency, preferred are --OC(CH.sub.3).sub.3,
--OCH.sub.2OCH.sub.3 and --OCH.sub.2OC.sub.2H.sub.5.
[0231] The fluorine-containing polymer having only OH group can be
used as a negative type resist in combination with a known
crosslinking agent.
[0232] Also in the case of use for a positive type resist, when OH
is present together with another acid-labile group, for example, a
functional group which is converted to COOH group due to action of
an acid, solubility in a developing solution and a dissolving rate
can be adjusted and resolution can be enhanced.
[0233] Also the introduction of OH group and COOH group to the
fluorine-containing polymer is preferred since adhesion to a
substrate can be improved.
[0234] In the photoresist composition of the present invention
(preferably a chemically amplifying photoresist composition), the
photoacid generator (B) is a compound which generates acid or
cation by irradiating the photoacid generator itself or the
photoresist composition containing the photoacid generator with
radiation. The photoacid generators can be used in a mixture of two
or more thereof.
[0235] Examples of the photoacid generator (B) are, for instance,
known compounds such as an organic halogen compound, sulfonic acid
ester, onium salt, diazonium salt, disulfone compound and a mixture
thereof.
[0236] Examples thereof are, for instance, haloalkyl
group-containing containing s-triazine derivatives such as
tris(trichloromethyl)-s-triazine, tris(tribromomethyl)-s-triazine,
tris(dibromomethyl)-s-triazine and
2,4-bis(tribromomethyl)-6-p-methoxyphenyl-s-triazine,
halogen-substituted paraffin hydrocarbons such as
1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon
tetrabromide and iodoform, halogen-substituted cycloparaffin
hydrocarbons such as hexabromocyclohexane, hexachlorocyclohexane
and hexabromocyclododecane, haloalkyl group-containing benzene
derivatives such as bis(trichloromethyl)benzene and
bis(tribromomethyl)benzene, haloalkyl group-containing sulfone
compounds such as tribromomethylphenyl sulfone and
trichloromethylphenyl sulfone, halogen-containing sulfolane
compounds such as 2,3-dibromosulfolane, haloalkyl group-containing
isocyanurates such as tris(2,3-dibromopropyl)isocyanurate,
sulfonium salts such as triphenylsulfonium chloride,
triphenylsulfoniummethane sulfonate,
triphenylsulfoniumtrifluoromethane sulfonate,
triphenylsulfonium-p-toluene sulfonate,
triphenylsulfoniumtetrafluoro borate, triphenylsulfoniumhexafluoro
arcenate and triphenylsulfoniumhexafluoro phosphonate, iodonium
salts such as diphenyl-iodonium-trifluoromethane-sulfonate,
diphenyl-iodonium-p-toluene-sulfonate, diphenyliodonium
tetrafluoroborate, diphenyliodonium hexafluoroarcenate and
diphenyliodonium hexafluorophosphonate, sulfonic acid esters such
as methyl p-toluenesulfonate, ethyl p-toluenesulfonate, butyl
p-toluenesulfonate, phenyl p-toluenesulfonate,
1,2,3-tris(p-toluenesulfonyloxy)benzene, p-toluenesulfonic acid
benzoin ester, methyl methanesulfonate, ethyl methanesulfonate,
butyl methanesulfonate, 1,2,3-tris(methanesulfonyloxy)benzene,
phenyl methanesulfonate, methane sulfonic acid benzoin ester,
methyl, trifluoromethanesulfonate, ethyl trifluoromethanesulfonate,
butyl trifluoromethanesulfonate,
1,2,3-tris(trifluoromethanesulfonyloxy)benzene, phenyl
trifluoromethanesulfonate and benzoin trifluoromethanesulfonate,
disulfones such as diphenyldisulfone, sulfonediazides such as
bis(phenylsulfonyl)diazomethane,
bis(2,4-dimethylphenylsulfonyl)diazomethane,
bis(cyclohexylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-methoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-methoxyphenylsulfonyl)diazomehtane,
cyclopentylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-methoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-methoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-fluorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-fluorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-fluorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-fluorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-fluorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-fluorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-chlorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-chlorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-chlorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-chlorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-chlorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-chlorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-trifluoromethyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-trifluoromethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-trifluoromethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-trifluoromethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-trifluoromethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-trifluoromethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2-methoxylphenylsulfonyl)diazomethane,
phenylsulfonyl-(3-methoxylphenylsulfonyl)diazomethane,
phenylsulfonyl-(4-methoxylphenylsulfonyl)diazomethane,
bis(2-methoxylphenylsulfonyl)diazomethane,
bis(3-methoxylphenylsulfonyl)diazomethane,
bis(4-methoxylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane,
2,4-dimethylphenylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
2,4-dimethylphenylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2-fluorophenylsulfonyl)diazomethane,
phenylsulfonyl-(3-fluorophenylsulfonyl)diazomethane and
phenylsulfonyl-(4-fluorophenylsulfonyl)diazomethane, o-nitrobenzyl
esters such as o-nitrobenzyl-p-toluenesulfonate, sulfone hydrazides
such as N,N'-di(phenylsulfonyl)hydrazide and the like.
[0237] Examples of the preferable photoacid generator are compounds
generating any of sulfonic acid, sulfenic acid or sulfinic acid.
Examples thereof are onium sulfonates such as
triphenylsulfonium-p-toluenesulfonate and
diphenyliodonium-p-toluenesulfonate, sulfonic acid esters such as
phenyl p-toluenesulfonate and
1,2,3-tris(p-toluenesulfonyloxy)benzene, disulfones such as
diphenyldisulfone, sulfonediazides such as
bis(phenylsulfonyl)diazomethane,
bis(2,4-dimethylphenylsulfonyl)diazomethane,
bis(cyclohexylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-methoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-methoxyphenylsulfonyl)diazomehtane,
cyclopentylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-methoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-methoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-fluorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-fluorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-fluorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-fluorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-fluorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-fluorophenylsulfonyl)diazomethane;
cyclohexylsulfonyl-(2-chlorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-chlorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-chlorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-chlorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-chlorophenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-chlorophenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-trifluoromethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-trifluoromethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-trifluoromethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-trifluoromethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-trifluoromethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-trifluoromethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(3-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(4-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(3-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(4-trifluoromethoxyphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane,
cyclohexylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane,
cyclopentylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2-methoxylphenylsulfonyl)diazomethane,
phenylsulfonyl-(3-methoxylphenylsulfonyl)diazomethane,
phenylsulfonyl-(4-methoxylphenylsulfonyl)diazomethane,
bis(2-methoxylphenylsulfonyl)diazomethane,
bis(3-methoxylphenylsulfonyl)diazomethane,
bis(4-methoxylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane,
2,4-dimethylphenylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,
2,4-dimethylphenylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane,
phenylsulfonyl-(2-fluorophenylsulfonyl)diazomethane,
phenylsulfonyl-(3-fluorophenylsulfonyl)diazomethane and
phenylsulfonyl-(4-fluorophenylsulfonyl)diazomethane, o-nitrobenzyl
esters such as o-nitrobenzyl-p-toluenesulfonate, and the like.
Particularly sulfonediazides are preferable.
[0238] Further in addition to the above-mentioned examples, a
photoacid generator of onium salts having fluorine atom can be
used. For example, there are preferably used a fluoroalkyl onium
salt represented by the formula: ##STR100## wherein A.sup.1 is an
element selected from iodine, sulfur, selenium, tellurium, nitrogen
and phosphorus; when A.sup.1 is iodine, R.sup.2-1 and R.sup.3-1 are
not present and R.sup.1-1 is an alkyl group having 1 to 15 carbon
atoms or an aryl group having 6 to 15 carbon atoms; when A.sup.1 is
sulfur, selenium or tellurium, R.sup.3-1 is not present and
R.sup.1-1 and R.sup.2-1 are independently an alkyl group having 1
to 15 carbon atoms, an aryl group having 6 to 20 carbon atoms, a
dialkylamino group having 2 to 30 carbon atoms, an alkylarylamino
group having 7 to 35 carbon atoms or a diarylamino group having 12
to 40 carbon atoms and R.sup.1-1 and R.sup.2-1 may be bonded to
each other to constitute a ring; when A.sup.1 is nitrogen or
phosphorus, R.sup.1-1, R.sup.2-1 and R.sup.3-1 are independently an
alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to
20 carbon atoms, a dialkylamino group having 2 to 30 carbon atoms,
an alkylarylamino group having 7 to 35 carbon atoms or a
diarylamino group having 12 to 40 carbon atoms and R.sup.1-1,
R.sup.2-1 and R.sup.3-1 may be bonded to each other to form one or
more rings, or R.sup.3-1 may not be present and R.sup.1-1 and
R.sup.2-1 may be bonded to each other to constitute an aromatic
ring including A.sup.1; the above-mentioned alkyl group, an alkyl
group of the dialkylamino group and an alkyl group of the
alkylarylamino group may be substituted with an aryl group, halogen
atom, oxygen atom, nitrogen atom, sulfur atom or silicon atom, may
be branched or may constitute a ring, and the above-mentioned aryl
group, an aryl group of the alkylarylamino group and an aryl group
of the diarylamino group may be substituted with an alkyl group,
haloalkyl group, halogen atom, alkoxyl group, aryloxy group, nitro
group, amide group, cyano group, alkanoyl group, aroyl group,
alkoxycarbonyl group, aryloxycarbonyl group or acyloxy group;
R.sub.f is a perfluoroalkyl group having 1 to 15 carbon atoms which
may be branched or may constitute a ring, or is the perfluoroalkyl
group in which a part of its fluorine atoms is substituted with
hydrogen atoms; X.sup.- is a conjugated base of Bronsted acid, or a
fluoroalkyl onium salt represented by the formula: ##STR101##
wherein A.sup.2 and A.sup.3 are the same or different and each is
an element selected from iodine, sulfur, selenium, tellurium,
nitrogen and phosphorus; when A.sup.2 or A.sup.3 is iodine,
R.sup.4-1, R.sup.5-1, R.sup.7-1 and R.sup.8-1 are not present; when
A.sup.2 or A.sup.3 is sulfur, selenium or tellurium, R.sup.5-1 and
R.sup.8-1 are not present and R.sup.4-1 and R.sup.7-1 are
independently an alkyl group having 1 to 15 carbon atoms, an aryl
group having 6 to 20 carbon atoms, a dialkylamino group having 2 to
30 carbon atoms, an alkylarylamino group having 7 to 35 carbon
atoms or a diarylamino group having 12 to 40 carbon atoms; when
A.sup.2 or A.sup.3 is nitrogen or phosphorus, R.sup.4-1, R.sup.5-1,
R.sup.7-1 and R.sup.8-1 are independently an alkyl group having 1
to 15 carbon atoms, an aryl group having 6 to 20 carbon atoms, a
dialkylamino group having 2 to 30 carbon atoms, an alkylarylamino
group having 7 to 35 carbon atoms or a diarylamino group having 12
to 40 carbon atoms, and R.sup.4-1 and R.sup.5-1 or R.sup.7-1 and
R.sup.8-1 may be bonded to each other, respectively to constitute a
ring; the above-mentioned alkyl group, an alkyl group of the
dialkylamino group and an alkyl group of the alkylarylamino group
may be substituted with an aryl group, halogen atom, oxygen atom,
nitrogen atom, sulfur atom or silicon atom, may be branched or may
constitute a ring, and the above-mentioned aryl group, an aryl
group of the alkylarylamino group and an aryl group of the
diarylamino group may be substituted with an alkyl group, haloalkyl
group, halogen atom, alkoxyl group, aryloxy group, nitro group,
amide group, cyano group, alkanoyl group, aroyl group,
alkoxycarbonyl group, aryloxycarbonyl group or acyloxy group,
R.sup.6-1 is an alkylene group having 1 to 15 carbon atoms which
may be substituted with an aryl group, halogen atom, oxygen atom,
nitrogen atom, sulfur atom or silicon atom, may be branched or may
constitute a ring; R.sub.f is a perfluoroalkyl group having 1 to 15
carbon atoms which may be branched or may constitute a ring, or is
the perfluoroalkyl group in which a part of its fluorine atoms is
substituted with hydrogen atoms; X.sup.- is a conjugated base of
Bronsted acid and the like.
[0239] Examples thereof are fluoroalkyl onium salts having iodine
atom as its center element: ##STR102##
[0240] Fluoroalkyl onium salt having sulfur atom as its center
element: ##STR103## ##STR104## ##STR105## ##STR106## ##STR107##
##STR108## ##STR109## ##STR110## ##STR111## ##STR112## ##STR113##
##STR114## ##STR115## ##STR116## ##STR117## ##STR118##
##STR119##
[0241] Fluoroalkyl onium salt having selenium atom as its center
element: ##STR120## ##STR121## ##STR122##
[0242] Fluoroalkyl onium salt haying tellurium atom as its center
element: ##STR123## ##STR124## ##STR125##
[0243] Fluoroalkyl onium salt having nitrogen atom as its center
element: ##STR126## ##STR127## ##STR128##
[0244] Fluoroalkyl onium salt having phosphorus atom as its center
element: ##STR129## ##STR130## ##STR131## ##STR132##
[0245] X.sup.- in those exemplified fluoroalkyl onium salts is a
conjugated base of Bronsted acid. Non-restricted examples of the
Bronsted acid are fluoroalkylsulfonic acids such as
trifluoromethanesulfonic acid, tetrafluoroethanesulfonic acid,
perfluorobutanesulfonic acid, perfluoropentanesulfonic acid,
perfluorohexanesulfonic acid, perfluorooctanesulfonic acid and
difluoromethanesulfonic acid, methanesulfonic acid,
trichloromethanesulfonic acid, benzenesulfonic acid,
toluenesulfonic acid, sulfuric acid, fluorosulfonic acid,
chlorosulfonic acid, HBF.sub.4, HSbF.sub.6, HPF.sub.6,
HSbCl.sub.5F, HSbCl.sub.6, HAsF.sub.6, HBCl.sub.3F, HalCl.sub.4 and
the like. Particularly fluoroalkylsulfonic acids which are strong
acids are preferred because neither hydrogen fluoride nor hydrogen
chloride is generated.
[0246] Those onium salts having a fluorine-containing alkyl group
are preferred because transparency thereof is high in a vacuum
ultraviolet region and also because of good compatibility with the
fluorine-containing polymer having an acid-reactive group in the
chemically amplifying photoresist composition of the present
invention.
[0247] The content of photoacid generator in the photoresist
composition of the present invention (chemically amplifying
photoresist composition) is preferably from 0.1 to 30 parts by
weight, more preferably from 0.2 to 20 parts by weight, most
preferably from 0.5 to 10 parts by weight based on 100 parts by
weight of the fluorine-containing polymer having an acid-reactive
group.
[0248] When the content of photoacid generator is less than 0.1
part by weight, sensitivity is lowered, and when the content is
more than 30 parts by weight, an amount of light absorbed by the
photoacid generator is increased and light does not reach a
substrate sufficiently, thereby lowering resolution easily.
[0249] Also to the photoresist composition of the present invention
may be added an organic base which can act, as a base, on an acid
generated from the above-mentioned photoacid generator.
[0250] The purpose of adding the organic base is to prevent
migration of the acid generated from the photoacid generator and to
prevent a resist pattern from undergoing a dimensional change
during an interval between the exposure and the PEB treatment.
Therefore the organic base is not limited particularly as far as it
is a compound being capable of neutralizing the acid generated from
the photoacid generator as mentioned above. The organic base is
preferred because when an inorganic compound is used as a base, a
very small amount of its residue remains after forming a pattern
and eliminating the resist and has an adverse effect on the pattern
formation. The organic base is an organic amine compound selected
from nitrogen-containing compounds. Examples thereof are pyrimidine
compounds such as pyrimidine, 2-aminopyrimidine, 4-aminopyrimidine,
5-aminopyrimidine, 2,4-diaminopyrimidine, 2,5-diaminopyrimidine,
4,5-diaminopyrimidine, 4,6-diaminopyrimidine,
2,4,5-triaminopyrimidine, 2,4,6-triaminopyrimidine,
4,5,6-triaminopyrimidine, 2,4,5,6-tetraminopyrimidine,
2-hydroxypyrimidine, 4-hydroxypyrimidine, 5-hydroxypyrimidine,
2,4-dihydroxypyrimidine, 2,5-dihydroxypyrimidine,
4,5-dihydroxypyrimidine, 4,6-dihydroxypyrimidine,
2,4,5-trihydroxypyrimidine, 2,4,6-trihydroxypyrimidine,
4,5,6-trihydroxypyrimidine, 2,4,5,6-tetrahydroxypyrimidine,
2-amino-4-hydroxypyrimidine, 2-amino-5-hydroxypyrimidine,
2-amino-4,5-dihydroxypyrimidine, 2-amino-4,6-dihydroxypyrimidine,
4-amino-2,5-dihydroxypyrimidine, 4-amino-2,6-dihydroxypyrimidine,
2-amino-4-methylpyrimidine, 2-amino-5-methylpyrimidine,
2-amino-4,5-dimethylpyrimidine, 2-amino-4,6-dimethylpyrimidine,
4-amino-2,5-dimethylpyrimidine, 4-amino-2,6-dimethylpyrimidine,
2-amino-4-methoxypyrimidine, 2-amino-5-methoxypyrimidine,
2-amino-4,5-dimethoxypyrimidine, 2-amino-4,6-dimethoxypyrimidine,
4-amino-2,5-dimethoxypyrimidine, 4-amino-2,6-dimethoxypyrimidine,
2-hydroxy-4-methylpyrimidine, 2-hydroxy-5-methylpyrimidine,
2-hydroxy-4,5-dimethylpyrimidine, 2-hydroxy-4,6-dimethylpyrimidine,
4-hydroxy-2,5-dimethylpyrimidine, 4-hydroxy-2,6-dimethylpyrimidine,
2-hydroxy-4-methoxypyrimidine, 2-hydroxy-5-methoxypyrimidine,
2-hydroxy-4,5-dimethoxypyrimidine,
2-hydroxy-4,6-dimethoxypyrimidine,
4-hydroxy-2,5-dimethoxypyrimidine and
4-hydroxy-2,6-dimethoxypyrimidine, pyridine compounds such as
pyridine, 4-dimethylaminopyridine and 2,6-dimethylpyridine, amines
substituted with hydroxyalkyl group and having not less than 1 and
not more than 4 carbon atoms such as diethanolamine,
triethanolamine, triisopropanolamine,
tris(hydroxymethyl)aminomethane and
bis(2-hydroxyethyl)iminotris(hydroxymethyl)methane, aminophenols
such as 2-aminophenol, 3-aminophenol and 4-aminophenol and the
like. Preferable organic bases are pyrimidines, pyridines or amines
having hydroxyl group, and particularly preferred are amines having
hydroxyl group. Those organic bases may be used alone or in a
mixture of two or more thereof. The content of organic base in the
photoresist composition of the present invention is preferably from
0.1 to 100% by mole, more preferably from 1 to 50% by mole based on
the content of photoacid generator. When the content of organic
base is less than 0.1% by mole, resolution is lowered, and when the
content of organic base is more than 100% by mole, sensitivity
tends to be lowered.
[0251] In the photoresist composition of the present invention
(chemically amplifying photoresist composition), when a negative
resist composition is prepared using the fluorine-containing
polymer, a crosslinking agent may be used as base demands as
mentioned above.
[0252] The crosslinking agent is not limited particularly and can
be optionally selected from crosslinking agents which have been
usually used for negative resists.
[0253] Examples of preferable crosslinking agent are, for instance,
N-methylol melamine, N-alkoxymethylol melamine compounds, urea
compounds, epoxy compounds, isocyanate compounds and the like.
[0254] Those crosslinking agents may be used alone or in a
combination of two or more thereof. Among them, a combination of
the melamine resin and the urea resin is advantageous.
[0255] The content of crosslinking agent in the photoresist
(particularly negative type) composition of the present invention
is from 3 to 70 parts by weight, preferably from 5 to 50 parts by
weight, more preferably from 10 to 40 parts by weight based on 100
parts by weight of the fluorine-containing polymer. When the
content is less than 3 parts by weight, a resist pattern is
difficult to be formed, and the content of more than 70 parts by
weight is not preferable because light transmittance is lowered,
resolution is easily lowered and developing property is
lowered.
[0256] The photoresist composition of the present invention may
contain, as case demands, various additives which have been usually
used in this field, such as dissolution inhibitor, sensitizer, dye,
adhesion betterment material and water storage material. While the
presence of water is necessary for generating an acid in a
chemically amplifying resist, the acid can be generated effectively
in the presence of a small amount of water storage material such as
polypropylene glycol.
[0257] When those additives are used, a total amount thereof is up
to about 20% by weight based on the weight of the whole solids in
the composition.
[0258] In the photoresist composition of the present invention
(chemically amplifying photoresist composition), the solvent (C) is
one which is capable of dissolving the fluorine-containing polymer,
the photoacid generator (B) and the above-exemplified various
additives. The solvent is not limited particularly as far as good
coatability (surface smoothness, uniformity of coating thickness,
etc.) can be obtained.
[0259] Examples of the preferable solvent (C) are, for instance,
cellosolve solvents such as methyl cellosolve, ethyl cellosolve,
methyl cellosolve acetate and ethyl cellosolve acetate, ester
solvents such as diethyl oxalate, ethyl pyruvate,
ethyl-2-hydroxybutyrate, ethyl acetoacetate, butyl acetate, amyl
acetate, ethyl butyrate, butyl butyrate, methyl lactate, ethyl
lactate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate,
methyl 2-hydroxyisobutyrate and ethyl 2-hydroxyisobutyrate,
propylene glycol solvents such as propylene glycol monomethyl
ether, propylene glycol monoethyl ether, propylene glycol monobutyl
ether, propylene glycol monomethyl ether acetate, propylene glycol
monoethyl ether acetate, propylene glycol monobutyl ether acetate
and dipropylene glycol dimethyl ether, ketone solvents such as
2-hexanone, cyclohexanone, methyl amino ketone and 2-heptanone,
aromatic hydrocarbons such as toluene, xylene, chlorobenzene and
chlorotoluene, a solvent mixture of two or more thereof and the
like.
[0260] Also in order to enhance solubility of the
fluorine-containing polymer, a fluorine-containing solvent may be
used as case demands.
[0261] Examples thereof are, for instance, CH.sub.3CCl.sub.2F
(HCFC-141b), a mixture of CF.sub.3CF.sub.2CHCl.sub.2 and
CClF.sub.2CF.sub.2CHClF (HCFC-225), perfluorohexane,
perfluoro(2-butyltetrahydrofuran), methoxy-nonafluorobutane,
1,3-bistrifluoromethylbenzene, and in addition, fluorine-containing
alcohols such as: [0262] H(CF.sub.2CF.sub.2.sub.nCH.sub.2OH (n: an
integer of from 1 to 3) F(CF.sub.2.sub.nCH.sub.2OH (n: an integer
of from 1 to 5) and (CF.sub.3.sub.2 CHOH, benzotrifluoride,
perfluorobenzene, perfluoro(tributylamine),
ClCF.sub.2CFClCF.sub.2CFCl.sub.2 and the like.
[0263] Those fluorine-containing solvents may be used alone, in a
mixture of two or more thereof or in a mixture of one or more of
the fluorine-containing solvents and non-fluorine-containing
solvents.
[0264] The amount of the solvent (C) is selected depending on kind
of solids to be dissolved, kind of a substrate to be coated, an
intended coating thickness, etc. From the viewpoint of easiness of
coating, it is preferable that the solvent is used in such an
amount that the concentration of the whole solids of the resist
composition becomes from 0.5 to 70% by weight, preferably from 1 to
50% by weight, particularly preferably from 5 to 30% by weight.
[0265] The photoresist composition of the present invention
(chemically amplifying resist composition) is subjected to resist
pattern formation according to conventional photoresist technology.
In order to form a pattern properly, first, a solution of the
resist composition is applied on a substrate such as a silicon
wafer by a spinner or the like, and is dried to form a
photosensitive layer. A pattern is drawn by irradiating the layer
with ultraviolet ray, deep-UV, excimer laser or X-ray by a
reduction projection exposure system, etc. through a proper mask
pattern or the pattern is drawn with an electron beam, and then
heating follows. The layer is then subjected to developing
treatment with a developing solution, for example, an aqueous
alkaline solution such as an aqueous solution of 1 to 10% by weight
of tetramethylammonium hydroxide. Thus an image faithful to the
mask pattern can be obtained by the above-mentioned pattern forming
method.
[0266] It was found that by using the photoresist composition of
the present invention (chemically amplifying resist composition), a
resist film (photosensitive layer) having a high transparency even
in a vacuum ultraviolet region could be formed. Therefore the
resist composition of the present invention can be preferably used
particularly for a photolithography process using a F.sub.2 laser
(wavelength of 157 nm) which is under development aiming at a
technology node of 0.1 .mu.m.
[0267] The tenth of the present invention relates to a
fluorine-containing cyclopentene having OH group which is
represented by the formula (70): ##STR133## wherein Rf.sup.70 is a
perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.70 is
fluorine atom or a perfluoroalkyl group having 1 to 20 carbon
atoms; X.sup.71 is hydrogen atom, fluorine atom, a hydrocarbon
group having 1 to 20 X.sup.72 carbon atoms or a perfluoroalkyl
group having 1 to 20 carbon atoms; X is hydrogen atom, fluorine
atom, OH group, a hydrocarbon group having 1 to 20 carbon atoms or
a perfluoroalkyl group having 1 to 20 carbon atoms; X.sup.73 is
hydrogen atom, fluorine atom, a hydrocarbon group having 1 to 20
carbon atoms or a perfluoroalkyl group having 1 to 20 carbon atoms;
when X.sup.72 is OH group, X.sup.73 is not fluorine atom, and the
fluorine-containing cyclopentene having OH group can impart
recurring units of monocyclic structure to the polymer.
[0268] This novel monocyclic monomer is high in copolymerizability
with a fluoroolefin as mentioned above, and therefore, OH group can
be introduced easily to the polymer and solubility in a developing
solution and other functions (for example, transparency in a vacuum
ultraviolet region) can be imparted to the polymer. Also since a
monocyclic structural unit can be introduced in the polymer trunk
chain, a glass transition temperature can be increased and
therefore the polymer is preferred from the viewpoint of dry
etching resistance.
[0269] In the above-mentioned formula (70), it is particularly
preferable that both of X.sup.70 and X.sup.71 are fluorine atoms or
perfluoroalkyl groups having 1 to 20 carbon atoms and further it is
preferable that X.sup.72 is OH group and X.sup.73 is a
perfluoroalkyl group having 1 to 20 carbon atoms, since excellent
solubility in a developing solution and transparency can be
imparted to the polymer.
[0270] Examples of the novel fluorine-containing cyclopentene
having OH group of the present invention are, for instance,
##STR134## and the like as mentioned above.
[0271] Those monomers which are novel cyclopentene derivatives can
be synthesized by the processes of the preparation schemes (1) to
(4) mentioned supra.
[0272] Those monomers can be polymerized alone using a radical
polymerization initiator or a cation polymerization initiator, and
further can be subjected to radical polymerization with the
above-mentioned various fluoroolefins (monomers providing the
structural unit M1), acrylic monomers and .alpha.-olefins, thereby
being capable of imparting hydrophilic property, solubility in a
developing solution, transparency and other various functions to
the polymer.
EXAMPLE
[0273] The present invention is then explained by means of examples
but is not limited to them.
[0274] In the following Examples, equipment and measuring
conditions used for evaluation of physical properties are as
follows.
(1) NMR: NMR analyzer is AC-300 available from BRUKER CO., LTD.
Measuring conditions of .sup.1H-NMR: 300 MHz (tetramethylsilane=0
ppm) Measuring conditions of .sup.19F-NMR: 280 MHz
(trichlorofluoromethane=0 ppm)
Measuring conditions of .sup.13C-NMR: 75 MHz (tetramethylsilane=0
ppm)
(2) IR analysis: Measuring is carried out at room temperature with
a Fourier-transform infrared spectrophotometer 1760X available from
Perkin Elmer Co., Ltd.
[0275] (3) GPC: A number average molecular weight is calculated
from data measured by gel permeation chromatography (GPC) by using
GPC HLC-8020 available from Toso Kabushiki Kaisha and columns
available from Shodex Co., Ltd. (one GPC KF-801, one GPC KF-802 and
two GPC KF-806M were connected in series) and flowing
tetrahydrofuran (THF) as a solvent at a flowing rate of 1
ml/minute.
Example 1
(Synthesis of Copolymer Comprising Cyclopentene and
Tetrafluoroethylene)
[0276] A 100 ml autoclave was charged with 3.4 g of cyclopentene:
##STR135## 40 ml of HCFC-141b and 0.3 g of
bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the inside
of a system was sufficiently replaced with nitrogen gas while
cooling with dry ice/methanol solution. Then 10.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.78
MPaG (8.0 kgf/cm.sup.2G) before the reaction to 0.75 MPaG (7.7
kgf/cm.sup.2G).
[0277] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with hexane to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 1.5 g of a copolymer was obtained. As a
result of .sup.1H-NMR and .sup.19F-NMR analyses, the copolymer was
one represented by the following formula. ##STR136##
[0278] The copolymer was one comprising TFE/cyclopentene in a
percent by mole ratio of 50/50 according to an elementary analysis.
According to GPC analysis, a number average molecular weight of the
copolymer was 5,700.
Example 2
(Synthesis of Copolymer Comprising 2,3-dihydrofuran and
Tetrafluoroethylene)
[0279] Reaction was carried out in the same manner as in Example 1
except that 3.5 g of 2,3-dihydrofuran: ##STR137## was used instead
of cyclopentene.
[0280] With the advance of the reaction, a gauge pressure was
decreased from 0.78 MPaG (8.0 kgf/cm.sup.2G) before the reaction to
0.75 MPaG (7.7 kgf/cm.sup.2G).
[0281] After releasing the un-reacted monomer, a polymer was
separated in the same manner as in Example 1 and 2.1 g of a
copolymer was obtained. As a result of .sup.1H-NMR and .sup.19F-NMR
analyses, the copolymer was one represented by the following
formula. ##STR138##
[0282] The copolymer was one comprising TFE/2,3-dihydrofuran in a
percent by mole ratio of 50/50 according to an elementary analysis.
According to GPC analysis, a number average molecular weight of the
copolymer was 17,000.
Example 3
(Synthesis of Copolymer Comprising Cyclooctene and
Tetrafluoroethylene)
[0283] A 100 ml autoclave was charged with 2.8 g of cyclooctene:
##STR139## 40 ml of HCFC-141b and 0.4 g of
bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the inside
of a system was sufficiently replaced with nitrogen gas while
cooling with dry ice/methanol solution. Then 10.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.88
MPaG (9.0 kgf/cm.sup.2G) before the reaction to 0.84 MPaG (8.6
kgf/cm.sup.2G).
[0284] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with methanol to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 2.7 g of a copolymer was obtained. As a
result of .sup.1H-NMR analysis, the copolymer was one represented
by the following formula. ##STR140##
[0285] The copolymer was one comprising TFE/cyclooctene in a
percent by mole ratio of 52/48 according to an elementary analysis.
According to GPC analysis, a number average molecular weight of the
copolymer was 9,900.
Example 4
(Synthesis of Copolymer Comprising 3,3'-Dimethylcyclopropene and
Tetrafluoroethylene)
[0286] A 300 ml autoclave was charged with 4.0 g of
3,3'-dimethylcyclopropene: ##STR141## 140 ml of HCFC-141b and 0.8 g
of bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the
inside of a system was sufficiently replaced with nitrogen gas
while cooling with dry ice/methanol solution. Then 23.5 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.80
MPaG (8.2 kgf/cm.sup.2G) before the reaction to 0.65 MPaG (6.6
kgf/cm.sup.2G).
[0287] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with methanol to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 1.7 g of a copolymer was obtained. As a
result of .sup.1H-NMR analysis, the copolymer was one represented
by the following formula. ##STR142##
[0288] The copolymer was one comprising
TFE/3,3'-dimethylcyclopropene in a percent by mole ratio of 61/39
according to an elementary analysis.
Example 5
(Synthesis of Copolymer Comprising Dicyclopentene and
Tetrafluoroethylene)
[0289] A 100 ml autoclave was charged with 3.4 g of dicyclopentene:
##STR143## 40 ml of HCFC-141b and 0.4 g of
bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the inside
of a system was sufficiently replaced with nitrogen gas while
cooling with dry ice/methanol solution. Then 10.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.90
MPaG (9.2 kgf/cm.sup.2G) before the reaction to 0.88 MPaG (9.0
kgf/cm.sup.2G).
[0290] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with methanol to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 1.0 g of a copolymer was obtained.
[0291] As a result of .sup.1H-NMR analysis, the copolymer was one
having the following structure. Also according to IR analysis, an
absorption of carbon-carbon double bond was recognized.
##STR144##
[0292] The copolymer was one comprising TFE/dicyclopentene in a
percent by mole ratio of 51/49 according to an elementary analysis.
Also according to IR analysis, an absorption of carbon-carbon
double bond was recognized. According to GPC analysis, a number
average molecular weight of the copolymer was 3,800.
Example 6
(Synthesis of Copolymer Comprising 2,3-dihydrofuran,
Tetrafluoroethylene and tert-butyl-.alpha.fluoroacrylate)
[0293] A 500 ml autoclave was charged with 7.0 g of
2,3-dihydrofuran, 5.8 g of tert-butyl-.alpha.fluoroacrylate, 40 ml
of HCFC-141b and 0.8 g of
bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the inside
of a system was sufficiently replaced with nitrogen gas while
cooling with dry ice/methanol solution. Then 40.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.88
MPaG (9.0 kgf/cm 2G) before the reaction to 0.86 MPaG (8.8
kgf/cm.sup.2G).
[0294] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with hexane to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 11.2 g of a copolymer was obtained.
[0295] As a result of .sup.1H-NMR and .sup.19F-NMR analyses, the
copolymer was one comprising
TFE/2,3-dihydrofuran/tert-butyl-.alpha.fluoroacrylate in a percent
by mole ratio of 23/33/44. According to GPC analysis, a number
average molecular weight of the copolymer was 18,000.
Example 7
(Synthesis of Copolymer Comprising Cyclopentene,
Tetrafluoroethylene and tert-butyl-.alpha.fluoroacrylate)
[0296] A 100 ml autoclave was charged with 3.4 g of cyclopentene,
1.5 g of tert-butyl-.alpha.fluoroacrylate, 40 ml of HCFC-141b and
0.3 g of bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and
the inside of a system was sufficiently replaced with nitrogen gas
while cooling with dry ice/methanol solution. Then 10.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.78
MPaG (8.0 kgf/cm.sup.2G) before the reaction to 0.77 MPaG (7.9
kgf/cm.sup.2G).
[0297] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with hexane to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 2.2 g of a copolymer was obtained.
[0298] As a result of .sup.1H-NMR and .sup.19F-NMR analyses, the
copolymer was one comprising
TFE/cyclopentene/tert-butyl-.alpha.fluoroacrylate in a percent by
mole ratio of 15.1/39.3/45.6. According to GPC analysis, a number
average molecular weight of the copolymer was 12,000.
Example 8
(Synthesis of Copolymer Comprising Cyclopentene,
Tetrafluoroethylene and tert-butyl-.alpha.fluoroacrylate)
[0299] Reaction was carried out in the same manner as in Example 7
except that 1.7 g of cyclopentene and 1.5 g of
tert-butyl-.alpha.fluoroacrylate were used. With the advance of the
reaction, a gauge pressure was decreased from 0.78 MPaG (8.0
kgf/cm.sup.2G) before the reaction to 0.74 MPaG (7.6
kgf/cm.sup.2G).
[0300] After releasing the un-reacted monomer, a polymer was
isolated in the same manner as in Example 7 and 1.7 g of a
copolymer was obtained.
[0301] As a result of .sup.1H-NMR and .sup.19F-NMR analyses, the
copolymer was one comprising
TFE/cyclopentene/tert-butyl-.alpha.fluoroacrylate in a percent by
mole ratio of 26.7/34.1/39.2. According to GPC analysis, a number
average molecular weight of the copolymer was 14,000.
Example 9
(Synthesis of Copolymer Comprising Cyclopentene,
Tetrafluoroethylene and tert-butyl-.alpha.fluoroacrylate)
[0302] Reaction was carried out in the same manner as in Example 7
except that 3.4 g of cyclopentene and 4.5 g of
tert-butyl-.alpha.fluoroacrylate were used. With the advance of the
reaction, a gauge pressure was decreased from 0.78 MPaG (8.0
kgf/cm.sup.2G) before the reaction to 0.75 MPaG (7.7
kgf/cm.sup.2G).
[0303] After releasing the un-reacted monomer, a polymer was
isolated in the same manner as in Example 7 and 3.5 g of a
copolymer was obtained.
[0304] As a result of .sup.1H-NMR and .sup.19F-NMR analyses, the
copolymer was one comprising
TFE/cyclopentene/tert-butyl-.alpha.fluoroacrylate in a percent by
mole ratio of 6.6/51.9/41.5. According to GPC analysis, a number
average molecular weight of the copolymer was 21,000.
Example 10
(Synthesis of Copolymer Comprising
2-cyclopentene-1-tert-butylacetate and Tetrafluoroethylene)
[0305] A 100 ml autoclave was charged with 4.6 g of
2-cyclopentene-1-tert-butylacetate: ##STR145## 40 ml of HCFC-141b
and 0.5 g of bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP),
and the inside of a system was sufficiently replaced with nitrogen
gas while cooling with dry ice/methanol solution. Then 10.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.98
MPaG (10.0 kgf/cm G) before the reaction to 0.96 MPaG (9.8
kgf/cm.sup.2G).
[0306] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with hexane to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 1.0 g of a copolymer was obtained. As a
result of .sup.1H-NMR analysis, the copolymer was one represented
by the following formula. ##STR146##
[0307] The copolymer was one comprising
TFE/2-cyclopentene-1-tert-butylacetate in a percent by mole ratio
of 50/50 according to an elementary analysis. According to GPC
analysis, a number average molecular weight of the copolymer was
1,800.
Example 11
(Synthesis of Copolymer Comprising Diallylmalonate Ethyl Ester and
Tetrafluoroethylene)
[0308] A 100 ml autoclave was charged with 9.6 g of diallylmalonate
ethyl ester: ##STR147## 40 ml of HCFC-225 and 0.18 g of
bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the inside
of a system was sufficiently replaced with nitrogen gas while
cooling with dry ice/methanol solution. Then 8.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 20 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.78
MPaG (8.0 kgf/cm.sup.2G) before the reaction to 0.64 MPaG (6.5
kgf/cm.sup.2G).
[0309] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by concentration and
re-precipitation with hexane to separate a copolymer. Until a
constant weight was reached, vacuum drying was continued and 12.0 g
of a copolymer was obtained.
[0310] As a result of an elementary analysis, the copolymer was one
comprising TFE/diallylmalonate ethyl ester in a percent by mole
ratio of 52/48. According to GPC analysis, a number average
molecular weight of the copolymer was 11,000.
[0311] As a result of IR and .sup.1H-NMR analyses, disappearing of
a peak of C.dbd.C double bond which could be recognized in a
diallylmalonate ethyl ester monomer was confirmed. Also according
to .sup.13C-NMR and DEPT analyses, it was confirmed that the
diallylmalonate ethyl ester unit in the copolymer was a 5-membered
ring represented by the following formula. ##STR148##
[0312] This copolymer was dissolved uniformly in the solvents such
as acetone, THF, DMF and HFC-225.
Example 12
(Synthesis of Cyclopentene Having --C(CF.sub.3).sub.2OH Group)
[0313] A 500 ml four-necked glass flask equipped with a blowing
tube was charged with 100 g of cyclopentadiene, followed by
stirring in nitrogen gas atmosphere while cooling in dry
ice/acetone bath. HCl gas was slowly introduced at a solution
temperature of not more than 0.degree. C. through a gas feeding
tube and sometimes the flask was separated to measure the weight
thereof. HCl gas was introduced up to 90% of theoretical amount to
synthesize 3-chlorocyclopentene which was not isolated and used for
the following reaction.
[0314] Magnesium was put in an amount of 24 g into a 1-liter
four-necked glass flask equipped with a blowing tube, dry ice
condenser and dropping funnel and was dried by heating in vacuo.
Thereto was added 200 ml of THF, followed by cooling in ice bath. A
solution obtained by mixing 31 g of previously prepared
3-chlorocyclopentene to 150 ml of THF was slowly added dropwise
through the dropping funnel in a state of the solution temperature
being 10.degree. to 15.degree. C. After completion of the addition,
hexafluoroacetone was introduced slowly through the gas feeding
tube so that the solution temperature did not exceed 20.degree. C.
Hexafluoroacetone was introduced until generation of heat was not
recognized. After completion of the introduction of
hexafluoroacetone, stirring was further continued at room
temperature for three hours. The reaction mixture was put in 500 ml
of 1N hydrochloric acid, followed by separating an organic layer,
washing with water, drying and distilling after concentration. As a
result, 56.0 g of fluorine-containing alcohol represented by the
formula: ##STR149## having a boiling point of from 62.degree. to
64.degree. C./45 mmHg was obtained. The monomer obtained above was
determined by .sup.19F-NMR, .sup.1H-NMR, .sup.13C-NMR and IR
analyses.
Example 13
(Synthesis of Copolymer Comprising Tetrafluoroethylene and
Cyclopentene Having --C(CF.sub.3).sub.2OH Group)
[0315] A 100 ml autoclave was charged with 5.5 g of the
cyclopentene having --C(CF.sub.3).sub.2OH group obtained in Example
12, 40 ml of HCFC-141b and 0.7 g of
bis(4-tert-butylcyclohexyl)peroxydicarbonate (TCP), and the inside
of a system was sufficiently replaced with nitrogen gas while
cooling with dry ice/methanol solution. Then 10.0 g of
tetrafluoroethylene (TFE) was introduced through a valve, followed
by shaking for reaction at 40.degree. C. for 18 hours. With the
advance of the reaction, a gauge pressure was decreased from 0.88
MPaG (9.0 kgf/cm.sup.2G) before the reaction to 0.85 MPaG (8.7
kgf/cm.sup.2G).
[0316] After releasing the un-reacted monomer, the polymerization
solution was removed, followed by re-precipitation with hexane to
separate a copolymer. Until a constant weight was reached, vacuum
drying was continued and 1.2 g of a copolymer having a structure
represented by the following formula was obtained. ##STR150##
[0317] As a result of .sup.1H-NMR and .sup.19F-NMR analyses, the
copolymer was one comprising TFE/cyclopentene having
--C(CF.sub.3).sub.2OH group in a percent by mole ratio of
50/50.
Example 14
(Measurement of Transparency at a Wavelength of 157 nm)
(1) Preparation of Coating Composition
[0318] The fluorine-containing polymers prepared in Examples 1 to
3, 6 to 10 and 13 were dissolved in butyl acetate so that the
concentration thereof became 3%, respectively. Thus coating
compositions were prepared.
(2) Coating
(i) Coating on a Substrate (MgF.sub.2) for Measuring
Transparency
[0319] Each coating composition was applied on a MgF.sub.2
substrate at room temperature with a spin coater under the
condition of 1,000 rpm. After the coating, the coating composition
was baked at 100.degree. C. for 15 minutes to form transparent
coating films.
(ii) Measurement of Coating Thickness
[0320] Coating films were formed by applying the respective coating
compositions under the same conditions as above except that a
silicon wafer was used instead of the MgF.sub.2 substrate.
[0321] The coating thickness was measured with a AFM device
(SPI3800 available from SEIKO DENSHI KABUSHIKI KAISHA). The results
are shown in Table 1.
(3) Measurement of Transparency in Vacuum Ultraviolet Region
(i) Measuring Device
[0322] Setani-Namioka type spectrometer (BL-7B available from HIGH
ENERGY KENKYU KIKO) [0323] Slit: 7/8-7/8 [0324] Detector: PMT
[0325] Grating (GII: Blaze wavelength 160 nm, 1,200
gratings/mm)
[0326] For an optical system, refer to Rev. Sic. Instrum., 60(7),
1917 (1989) by H. Namba, et al.
(ii) Measurement of Transmitting Spectrum
[0327] A transmitting spectrum at a wavelength of 200 to 100 nm in
a coating film formed by applying each coating composition on the
MgF.sub.2 substrate by the method of (2)(i) was measured using the
above-mentioned device.
[0328] A molecular absorption coefficient was calculated from the
transmittance at 157 nm and the coating thickness and is shown in
Table 1.
Example 15
(Evaluation of Dry Etching Resistance)
[0329] 10% butyl acetate solutions of fluorine-containing polymers
prepared in Examples 1 to 3, 6 to 10 and 13 were prepared and
coated on a Si substrate with a spin coater so that the coating
thickness became 200 nm. After the coating film was pre-baked at
120.degree. C. for 2 minutes, the coating thickness was measured
with an interference coating thickness meter. Then the coated
substrate was put in a chamber of ICP (inductively-coupled plasma)
etching equipment to carry out etching. A pressure of etching gas
(Ar/N.sub.2/C.sub.4F.sub.8 mixed gas) was 1.33 Pa (10 mTorr).
Plasma etching was carried out at 13.56 MHz and 900 W for an upper
electrode and at 400 kHz and 100 W for a lower electrode. An
etching time was 60 seconds.
[0330] The coating thickness after the etching was measured with an
interference coating thickness meter and an etching rate was
calculated. For comparison, an etching rate was obtained similarly
using a resist (TArF-6a-63 available from Tokyo Oka Kabushiki
Kaisha) used for lithography for ArF laser. The etching rate is
represented in comparison with the rate obtained for comparison.
Namely, each etching rate is shown by a ratio to the etching rate
of comparative polymer (the above-mentioned resist for ArF laser)
provided that the latter etching rate is 1. The results are shown
in Table 1.
Example 16
(Evaluation of Solubility in Developing Solution)
(1) Deprotection Reaction of Protective Group
[0331] Each protective group contained in the fluorine-containing
polymers of Examples 6 to 10 and 13 was subjected to deprotection
by reacting the fluorine-containing polymers with trifluoroacetic
acid by using dichloromethane solvent.
[0332] It was confirmed by .sup.1H-NMR and IR analyses that 85% or
more of protective groups were deprotected and converted to COOH
group.
(2) Coating
[0333] 10% butyl acetate solutions of fluorine-containing polymers
prepared in Examples 6 to 10 and 13 and deprotected
fluorine-containing polymers obtained above were prepared and
coated on a Si substrate with a spin coater so that a coating
thickness became 200 nm, followed by drying.
(3) Determination of Solubility
[0334] The Si substrate after the drying was dipped in a 2.38%
aqueous solution of tetramethylammonium hydroxide for 60 seconds.
Then the substrate was removed and dried at room temperature, and
whether or not there was a remaining film was checked with naked
eyes.
[0335] When there remain no film, solubility is assumed to be
.largecircle.. The results are shown in Table 1
Example 17
(1) Preparation of Coating Composition
[0336] The fluorine-containing polymers prepared in Examples 6 to
10 and 13 and a photoacid generator (B) in an amount of 5% by
weight based on the polymer were dissolved in butyl acetate as the
solvent (C) and a concentration of the polymer was diluted to 5% by
weight.
[0337] As the photoacid generator,
S-(trifluoromethyl)-dibenzothiopheniumtrifluoromethane sulfonate:
##STR151## was used. (2) Coating
[0338] Coating compositions were coated on a Si substrate with a
spin coater so that a coating thickness became 200 nm, followed by
drying.
(3) Measurement of Transparency in Vacuum Ultraviolet Region
[0339] Measurement was made in the same manner as in Example 14. A
molecular absorption coefficient at 157 nm is shown in Table 1.
TABLE-US-00001 TABLE 1 Ex. 16 Solubility in Ex. 14 Ex. 15
developing Ex. 17 Absorption Etching solution Absorption Fluorine-
coefficient rate Before After coefficient containing at 157 nm (to
ArF depro- depro- at 157 nm polymer (.mu.m.sup.-1) resist) tection
tection (.mu.m.sup.-1) Ex. 1 0.9 0.8 -- -- -- Ex. 2 1.0 0.9 -- --
-- Ex. 3 1.1 0.9 -- -- -- Ex. 6 3.5 1.05 X .largecircle. 3.7 Ex. 7
3.6 1.2 X .largecircle. 3.9 Ex. 8 3.7 1.1 X .largecircle. 3.9 Ex. 9
4.1 1.5 X .largecircle. 4.4 Ex. 10 3.2 0.9 X .largecircle. 3.4 Ex.
13 0.7 1.0 .largecircle. -- 1.0
Example 18
(Synthesis of Fluorine-Containing Cyclopentene Derivative Having OH
Group)
(1) Synthesis of CF.sub.3COCF.sub.2COCF.sub.3
[0340] A 500 ml four-necked glass flask was charged with 31.2 g of
CF.sub.3COCH.sub.2COCF.sub.3 and 250 ml of acetonitrile, followed
by replacement with nitrogen at 0.degree. C. The mixture was cooled
to -10.degree. C. and thereto was introduced 10% by volume of
F.sub.2/N.sub.2 (600 mmol as F.sub.2, four times the molar
quantity) over five hours. As a result, the solution temperature
was increased to a temperature near 5.degree. C. After the
introduction of fluorine gas, nitrogen gas was flowed at 0.degree.
C. for 30 minutes to purge fluorine gas. Then a solution prepared
by dissolving 52 g of BF.sub.3.NEt.sub.3 in 20 ml of acetonitrile
was added dropwise at 0.degree. C. After completion of the
addition, stirring was further carried out at room temperature for
15 hours and the flask was heated to 50.degree. C. in an oil bath,
followed by distilling in nitrogen gas atmosphere to obtain 26.4 g
of CF.sub.3COCF.sub.2COCF.sub.3 (boiling point: 34.degree. to
35.degree. C.). According to .sup.19F-NMR, .sup.1H-NMR,
.sup.13C-NMR and IR analyses, the obtained product was determined
as CF.sub.3COCF.sub.2COCF.sub.3.
(2) Synthesis of Diene.Diol Derivative with CH.sub.2.dbd.CHMgBr and
C.sub.2H.sub.5OCH.sub.2Cl
[0341] The inside of a 500 ml four-necked glass flask was replaced
with nitrogen and 10.5 g of CF.sub.3COCF.sub.2COCF.sub.3 and 50 ml
of THF were introduced thereto, followed by cooling the flask in an
ice bath. Then 129 ml of 1N THF solution of CH.sub.2.dbd.CHMgBr was
slowly added thereto dropwise so that the solution temperature did
not exceed 10.degree. C. After completion of the addition, the
solution temperature was increased to room temperature over one
hour and the flask was again cooled to 0.degree. C. in an ice bath.
Then 21.3 g of C.sub.2H.sub.5OCH.sub.2Cl and 81 ml of DMF were
slowly added thereto dropwise through a dropping funnel so that the
solution temperature did not exceed 10.degree. C. After stirring at
room temperature for 24 hours, the reaction solution was poured
into 1 liter of water to separate an organic layer. An aqueous
layer was extracted with 200 ml of hexane, and washed together with
the organic layer using 200 ml of 1N HCl two times and 200 ml of
saturated brine once, followed by drying with potassium carbonate,
concentrating with an evaporator and separating and collecting a
concentrated residue with a silica gel column (a developing solvent
was ethyl acetate:hexane=1:15, Rf value was 0.2). The obtained
fraction was concentrated with an evaporator and 15.2 g of
diene-diol derivative represented by the formula: ##STR152## was
obtained. The above-mentioned structure was determined according to
.sup.19F-NMR, .sup.1H-NMR, .sup.13C-NMR and IR analyses. (3)
Synthesis of Cyclopentene.Diol Derivative by Metathesis
Ring-Closing Reaction
[0342] In 50-liter two-necked flask was put 0.8 g of
PhCH.dbd.RuCl.sub.2 (PCy.sub.3).sub.2 (Cy represents cyclohexyl),
followed by replacement with nitrogen. Then thereto were added 2
liter of CH.sub.2Cl.sub.2 subjected to drying and deaeration and
8.32 g of diene.diol derivative prepared above. Stirring was
continued at room temperature for 24 hours, followed by
concentrating and separating and collecting with a silica gel
column (a developing solvent was ethyl acetate:hexane=1:20, Rf
value was 0.25). The obtained fraction was concentrated with an
evaporator and 6.21 g of cyclopentene.diol derivative represented
by the formula: ##STR153## was obtained. The above-mentioned
structure was determined according to .sup.19F-NMR, .sup.1H-NMR,
.sup.13C-NMR and IR analyses. (4) Deprotection of Cyclopentene.Diol
Derivative
[0343] In a four-necked flask equipped with a refluxing tube were
put 15 g of cyclopentene.diol derivative obtained above, 40 ml of
dichloromethane, 4 g of trifluoroacetic acid and 1 g of water,
followed by refluxing at 40.degree. C. for 12 hours. The separation
of solution and distillation were carried out and 8.5 g of
fluorine-containing cyclopentene.diol represented by the formula:
##STR154## was obtained. The above-mentioned structure was
determined according to .sup.19F-NMR, .sup.1H-NMR, .sup.13C-NMR and
IR analyses.
Experimental Example 1
(Relation Between pKa Value and .DELTA.H of Fluorine-Containing
Ethylenic Monomer Having OH Group)
(1) Calculation of .DELTA.H of Fluorine-Containing Ethylenic
Monomers Having OH Group
[0344] With respect to various fluorine-containing ethylenic
monomers having OH group shown in Table 2, calculation of molecular
orbital was carried out by the above-mentioned MOPAC97, AM1 method
to calculate a produced enthalpy H(M-OH) before acid dissociation
and a produced enthalpy H(M-O.sup.-) after acid dissociation. With
respect to the monomers having a long chain, calculation of
molecular orbital was carried out using the model structures shown
in Table 2. Then provided that a produced enthalpy of hydrogen ion
is a constant of 200 kJ/mol, each produced enthalpy was substituted
in the following Equation 3: .DELTA.H.dbd.H(M-O.sup.-)+200-H(M-OH)
(Equation 3) to obtain .DELTA.H (kJ/mol). The results are shown in
Table 2. (2) (Measurement of pKa Value of Various
Fluorine-Containing Compounds Having OH Group) Measurement of pKa
Value of Cyclopentene Derivative Having --C(CF.sub.3).sub.2OH Group
##STR155##
[0345] In a water/acetone mixture (10/15 ml) solution was put
0.4045 g of the above-mentioned cyclopentene derivative, followed
by stirring at room temperature. After it was confirmed that the
solution became homogeneous, titration was carried out with about
0.2 mol/liter NaOH solution. A titration curve was obtained by
adding a NaOH solution dropwise in increments of 0.15 ml and
recording a pH value at every addition. An equivalence point was
determined by an inflection point (maximum differential value of
titration curve=dpH/dml) of the titration curve. In this case, the
equivalence point was 8.0 ml. A pH value at 4.0 ml which was a half
of the equivalence point was read from the titration curve and was
found to be 11.12. From a titration curve of water/acetone solution
and aqueous solution which had been measured previously as a blank
solution, a difference in a pH value derived from an electric
potential difference between the solutions at titration of 4.0 ml
was 1.50. Therefore from 11.12-1.50=9.62, a pKa value of this
norbornene derivative was determined as 9.62.
[0346] In the case of titration of 0.8104 g of cyclopentene
derivative by the same procedures as above, an equivalence point
was 16.4 ml and a half of equivalence point was 8.4 ml. A pH value
at a half of the equivalence point was 11.14. A difference in a pH
value between the both solutions at 8.4 ml was 1.19, and from
11.14-1.19=9.95, a pKa value of the cyclopentene derivative was
determined as 9.95.
[0347] In the case of titration of 0.9812 g of cyclopentene
derivative by the same procedures as above, an equivalence point
thereof was 18.95 ml and a half of equivalence point was 9.48 ml. A
pH value at this time was 11.03. A difference in a pH value between
the both solutions at 9.48 ml was 1.17, and from 11.03-1.17=9.86, a
pKa value of the cyclopentene derivative was determined as
9.86.
[0348] From those experiments carried out three times, a pKa value
of the cyclopentene derivative was determined as 9.8.
[0349] With respect to the various fluorine-containing compounds
having OH group shown in Table 2, a pKa value was measured by the
same procedures as above. The results are shown in Table 2.
(3) Relation Between .DELTA.H and Actually Measured pKa
[0350] With respect to the various fluorine-containing compounds
having OH group shown in Table 2, FIG. 1 is a graph in which
calculated .DELTA.H and actually measured pKa are plotted in an
abscissa and an ordinate, respectively. As shown in FIG. 1, it was
found that a good proportional relation is exhibited.
[0351] From the graph, an equation: (pKa)=0.0442.DELTA.H+6.8613
(Equation 4)
[0352] (R.sup.2=0.9224) was obtained. TABLE-US-00002 TABLE 2
Fluorine-containing compound having OH group Model structure (1)
.DELTA.H (2) pKa ##STR156## ##STR157## 60.5 9.8 ##STR158##
##STR159## 59.5 10.2 ##STR160## ##STR161## 40.4 9.0 ##STR162##
##STR163## 29.9 8.3 ##STR164## ##STR165## 116.3 11.5
CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH
CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH 74.2 9.6
CF.sub.2.dbd.CF--C(CF.sub.3).sub.2OH
CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH 13.2 7.1
CF.sub.3CH(CF.sub.3)--OH CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH
50.4 9.3 CH.sub.2.dbd.CF--C(CF.sub.3).sub.2OH
CH.sub.2.dbd.CHCH.sub.2C(CF.sub.3).sub.2OH 38.7 8.0 ##STR166##
##STR167## 122.3 12.6
[0353] The novel fluorine-containing polymer of the present
invention possesses dry etching resistance higher than that of
polymers prepared using norbornene and transparency thereof even in
a vacuum ultraviolet region is excellent as compared with polymers
prepared using norbornene.
[0354] Also the copolymer obtained by copolymerizing a fluoroolefin
with the novel unsaturated compound having a monocyclic structure
of the present invention which has an acid-reactive functional
group directly bonded to a ring and partly contains fluorine
possesses an excellent dry etching resistance and high transparency
when used for a resist.
* * * * *