Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-02-26
2004-03-30
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S271000, C525S291000, C525S293000, C525S294000, C525S299000, C525S326500, C525S328500, C526S313000
Reexamination Certificate
active
06713564
ABSTRACT:
RELATED APPLICATION
This application claims the benefit of International Application PCT/JP00/05919 filed Aug. 31, 2000 and which published in the Japanese language with an English abstract only as WO 01/16198 on Aug. 3, 2001.
TECHNICAL FIELD
The present invention relates to a star block copolymer with an arm moiety having an alkenylphenol homopolymer or copolymer as polymer chains and a process for producing the same. The star block copolymer of the present invention is a compound anticipated to be utilized as a resist material for excimer lasers and electron beams.
BACKGROUND ART
Alkenylphenol homopolymers and copolymers of which poly-p-hydroxystyrene is a representative are useful as resist materials for excimer lasers of chemical amplification. Among them, resists using a poly-(p-hydroxystyrene) or (p-hydroxystyrene/styrene) copolymer are known as resists capable of imaging with high resolution.
In regards to star block copolymers, for example, in Japanese Unexamined Patent Publication No. 222114 of 1993, a star polymer has been described in which a block copolymer molecule is produced by anionic polymerization of isoprene and styrene, coupled with a polyalkenyl coupling agent at 2.5 moles or more per 1 mole of the block copolymer molecule, and further 95% or more of isoprene units (olefin unsaturated) and less than 15% of styrene units (aromatic unsaturated) are selectively hydrogenated.
Japanese Unexamined Patent Publication No. 220203 of 1994 has described a modified block copolymer comprising a core crosslinking with a polyfunctional coupling agent, and comprising at least one type of polymer block induced from unsaturated carboxylate ester of alkyl, and at least one type of polymer block induced from conjugated diene and/or at least one type of a polymer block induced from monovinyl aromatic compound.
Japanese Unexamined Patent Publication No. 256436 of 1994 has described a polymer comprising at least three first arms with peak molecular weight of from 10,000 to 200,000 comprising hydrogenated polymerization conjugated diene; at least three second arms with peak molecular weight of from 500 to 10,000 comprising polymerized methacrylate and/or an amido or imide derivative thereof; and a central core connecting the first arms and second arms in a star configuration and comprising polymerized bis unsaturated monomer.
Japanese Unexamined Patent Publication No. 97413 of 1995 has described a star block polymer having the general formula:
wherein C is a block of crosslinked bis unsaturated monomer; each A is independently a block of anionic polymerization monomer; M is a block of polymerization methacrylic acid alkyl polymerized through ethylene unsaturation of methacrylic acid moiety; r is 0 or 1; and s and t are an average of 2 or more but s≦t wherein the molecular weight of from 20,000 to 2,000,000 and A is styrene or isoprene.
Japanese Unexamined Patent Publication No. 48987 of 1996 has described a star polymer having the structure represented by (EP′-S-EP″) n-X wherein EP′ is a first hydrogenated block of polyisoprene (I′) with the number average molecular weight (Mn) before hydrogenation of from 10,000 to 100,000, S is polystyrene block with the average molecular weight (Mn) of from 6,000 to 50,000, EP″ is a second hydrogenated block of polyisoprene (I″) with the number average molecular weight (Mn) before hydrogenation of from 2,500 to 50,000, a molecular ratio of I′/I″ is at least 1.4, X is a core consisting of a polyalkenyl coupling agent, and n is an average arm number per star molecule formed by reacting the polyalkenyl coupling agent at 2 moles or more for one mole of (EP′-S-EP″), wherein the star polymer consists of an intramolecular bound polystyrene block and hydrogenated polyisoprene block and is useful as an improver of the viscosity index (VI).
Japanese Unexamined Patent Publication No. 81514 of 1996 has described a polyfunctional initiator of anionic polymerization, which is soluble in non-polar solvents, not containing (or substantially not containing) any residual double bond and represented by the general formula, (PA)
a
N
r.−
nLi
+
wherein PA represents a polymer block generated from at least one type of monomer A selected from vinyl aromatic monomers and diene monomers; a represents a number of arms of PA block, from 3 to 30, especially from 3 to 15; N represents a crosslinked core not containing or substantially not containing any residual double bond and has the formula, (PMc) (RLi) p wherein Mc is a monomer containing at least two polymerized double bonds per molecule; PMc is a crosslinked core of at least one type of polymerization monomer Mc containing from 3 to 30% residual double bonds for initial double bonds derived from monomer Mc; R is an alkyl group and the like having straight or branched chains; and p is a number of residual double bonds in PMc neutralized with RLi; n is a number of anion sites present in the crosslinked PMc core and equal to a+p (or p) (p has the above meanings, and a is a number of anion sites present in the crosslinked core before addition of RLi.)
Japanese Patent Publication No. 504865 of 1996 has described a star block copolymer comprising (a) at least three arms from at least one anion polymerized monomer selected from the group consisting of monovinyl aromatic hydrocarbon, conjugated diene and the mixtures thereof, (b) at least three arms comprising polydimethyl siloxane and (c) a core comprising a polyalkenyl aromatic coupling agent (the above (a) and (b) radiate out from this core).
Published Japanese Translation of PCT International Publication for Patent Applications No. 505179 of 1996 has described a block copolymer of the general formula (A-B)n(B) mX wherein A is a block of polystyrene having peak molecular weight of less than 15,000, B is a polymer block of hydrogenated conjugated diene having peak molecular weight ranging from 15,000 to 50,000, X is a block of divinylbenzene, and n and m are integers of 0 or more wherein a sum of n and m is at least 10.
Published Japanese Translation of PCT International Publication for Patent Applications No. 510236 of 1997 has described a star copolymer containing (a) four molecules or more of polyfunctional binders forming a core selected from the group consisting of divinyl aromatic compound, trivinyl aromatic compound, diepoxide, diketone, and aldehyde; and (b) three or more of cation polymer branches bound to said core wherein said polymer branch is selected from the group consisting of a homopolymer, copolymer and block copolymer having at least one polyolefin segment and at least one polyaryl segment, and a graft copolymer.
DISCLOSURE OF THE INVENTION
Polymers with higher molecular weights have been conventionally known to be more preferable as base polymers for positive resist materials in terms of resolution, heat resistance and the like. However, when a molecular structure of a base polymer is accompanied with high molecular weight as a conventional linear structure, it has been problematic in that resist viscosity is increased resulting in difficulty of spin coating though resist application on substrates is usually performed by spin coating.
Among the star block copolymers described above, those having a hydroxystyrene skeleton at an arm moiety have not been known.
The subject of the present invention is to provide a novel star block copolymer which can be made to have a high molecular weight as a solution and has a lower viscosity than solutions of linear polymers having the same molecular weight as the copolymer and which is expected to be used as a resist material; and a process for producing the copolymer.
As results of an intensive study to achieve said subject, the present inventors have found that the star block copolymer with a narrow molecular weight range having alkenylphenol skeletons of which structure is controlled is obtained by homopolymerizing by living anionic polymerization an alkenylphenol compound in which the hydroxyl group of the phenol moiety has been prote
Kobayashi Asami
Matsumoto Hitoshi
Mitsuhiro Nakamura
Nobuhara Yukikazu
LaPointe Dennis G.
Mason Law, P.A.
Nippon Soda Co. Ltd.
Teskin Fred
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