Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-04-28
2001-09-04
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S205000, C528S211000, C528S212000, C525S191000, C525S242000, C525S328800
Reexamination Certificate
active
06284863
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to polymers having O-substituted vinylphenol unit which is usable as a component of resist, and to resist compositions containing them.
In recent years, quarter-micron pattern formations have been demanded with the increase in the integration level of semi-conductor integrated circuits. Particularly, the eximer laser lithography has attracted attention because it enables producing 64 M to 1G DRAM (dynamic random access memory). As a resist suitable for such eximer laser lithography process, a resist utilizing the chemical amplification effects of an acid catalyst, generally called chemical amplification type resist, has been proposed and is putting in the practical use. For example, in the negative working chemical amplification type resist, an acid is generated from an acid generator by the action of high-energy radiation such as electromagnetic waves, and the solubility of a part exposed to a high-energy radiation of an alkali-soluble resin in an alkaline developing solution is reduced by cross-linking and hardening by the action of the generated acid and a cross-linking agent. On the other hand, the acid does not generate in a part that is not exposed to a high-energy radiation and thus the solubility in the alkaline developing solution is maintained. By such a mechanism, a negative working pattern is obtained by a series of treatments, i.e., a formation of a resist film, an irradiation for patterning and an alkaline development.
Conventionally, polyvinylphenol has been used in most cases as a resin for a chemical amplification type resist. Since, however, polyvinylphenol has a too high solubility in alkaline developing solutions, they have a problem that the sensitivity and the resolution are insufficient. In order to resolve such a problem, use of a polyvinylphenol in which phenolic hydroxyl groups are partly converted to alkyl ethers have been disclosed in JP-A-7-295220 and JP-A-10-69082.
While the use of a polyvinylphenol in which phenolic hydroxyl groups are partly converted to alkyl ethers allows improvement in the sensitivity and the resolution, there is a limit of about 0.22 &mgr;m for the resolution particularly of negative working resists. Therefore, improvement has been demanded in this respect. In addition, there is a demand for improvement in the profile (shape of pattern). Moreover, the facts are naturally required that the performance is not changed by the variation of period from the time of coating and drying a resist solution on a substrate to the time of exposing to rays., in other words, the storage stability after coating and before light-exposure is excellent; and that a change in the performance is not significant during a long term storage of a resist composition itself, in other words, the storage stability of the resist composition itself is acceptable.
The purpose of the present invention is to provide a novel polymer which gives an excellent resolution and profile when used as a resin component in a resist composition and gives an acceptable result for the sensitivity, film-forming rate, the coating property, the storage stability after coating and before light-exposure and the storage stability of resist composition itself. The purpose of the present invention is also to provide a resist composition having an excellent performances as described above, using such polymer. As the result of extensive studies for attaining such a purpose, the present inventors have successfully completed the present invention.
SUMMARY OF THE INVENTION
The present invention provides a polymer having an O-substituted vinylphenol unit represented by the following formula (I)
wherein R
1
, R
2
and R
3
independently represent an alkyl, having 1 to 4 carbon atoms, which may be optionally substituted: or R
1
and R
2
, R
1
and R
3
or R
2
and R
3
are bound together and respectively form an alkylene, having 2 to 9 carbon atoms, which may be optionally substituted; or R
2
is methylidyne wherein one bond in the methylidyne is bound to R
1
, the other bond is bound to R
3
, and R
1
and R
3
independently represent alkylene., having 2 to 9 carbon atoms, which may be optionally substituted.
The present invention also provides a resist composition comprising such a polymer as a resin component.
DETAILED DESCRIPTION OF THE INVENTION
In the formula (I) described above, when R
1
and R
2
are bound together and form an alkylene. The O-substituted vinylphenol unit of the formula (I) can specifically be represented by the following formula (Ia). When R
1
and R
3
are bound together and form an alkylens, the O-substituted vinylphenol unit of the formula (I) can specifically be represented by the following formula (Ib). When R
2
and R
3
are bound together and form an alkylene, the O-substituted vinylphenol unit of the formula (I) can specifically be represented by the following formula (Ic). When R
2
is methylidyne and one bond in the methylidyne is bound to R
1
, the other bond is bound to R
3
, and R
1
and R
3
represent an alkylene respectively, the O-substituted vinylphenol unit of the formula (I) can specifically be represented by the following formula (Id):
wherein R
11
, R
12
and R
13
independently represent an alkyl, having 1 to 4 carbon atoms, which may be optionally substituted; and X, Y and Z independently represent an alkylene, having 2 to 9 carbon atoms, which may be optionally substituted.
The polymer of the present invention may be either a homopolymer substantially consisting of O-substituted vinylphenol unit represented by the above formula (I) alone, or a copolymer having, together with the above unit, another unit derived from any vinyl compound. It is advantageous that another unit is a vinylphenol unit, namely a unit represented by the following formula (II):
In the formula (I), the group —OCH(R
1
)N(R
2
)COR
3
may be bound to anyone of o-position, m-position and p-position in benzene ring which is a pendant on the main chain of the polymer. Generally, it is bound to p-position because of the availability of raw material.
When R
1
and R
2
, R
1
and R
3
or R
2
and R
3
in the formula (I) are bound together and respectively form an alkylene having 2 to 9 carbon atoms, or when R
2
in the formula (I) is methylidyne wherein one bond In the methylidyne is bound to R
1
, the other bond is bound to R
3
, and R
1
and R
3
respectively form an alkylone having 2 to 9 carbon atoms, the alkylene may be polymethylene of straight chain or may be a branched chain. Therefore, X, Y and Z in the formulae (Ia), (Ib) or (Ic) and X and Z in the formula (Id) may also be polymethylene of straight chain or may be a branched chain. Polymethylene has usually about 2 to 5 carbon atoms.
Examples of the group which may be a substituent on alkyl represented by R
1
, R
2
or R
3
in the formula (I), or on alkylene formed by R
1
and R
2
, R
1
and R
3
or R
2
and R
3
in the formula (I), i.e. alkylene represented by X, Y and Z in the formulae (Ia), (Ib) or (Ic), or on alkylene formed by R
2
or R
3
when R
2
in the formula (I) is methylidyne wherein one bond in the methylidyne is bound to R
1
, the other bond is bound to R
3
, i.e. X and Z in the formula (Id), include alkoxy having 1 to 4 carbon atoms, alkoxycarbonyl wherein its alkyl part has 1 to 4 carbon atoms. acyl having 1 to 5 carbon atoms in total, and acyloxy having 1 to 5 carbon atoms in total. Specific examples of the alkoxy include methoxy, ethoxy, propoxy and butoxy, and this is also applied to specific examples of alkoxy in the alkoxycarbonyl. Specific examples of the acyl include formyl, acetyl, propionyl, butyryl, valeryl and pivaloyl, and this is also applied to specific examples of acyl in the acyloxy.
In the formula (I), preferably at least one of R
1
, R
2
and R
3
is an alkyl as described above, more preferably unsubstituted alkyl. Particularly preferred alkyl is methyl or ethyl. The alkylene formed by binding a part or whole of R
1
, R
2
and R
3
in the formula (I), i.e. The alkylene represented by X, Y or Z in formulae (Ia), (Ib), (Ic) and
Kim Sang-tae
Ohta Yoshiteru
Suetsugu Masumi
Birch & Stewart Kolasch & Birch, LLP
Sumitomo Chemical Company Ltd.
Truong Duc
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