# US 10,310,376 B2 · Resist composition, pattern forming process, polymer, and monomer

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- Number: US 10,310,376 B2
- Document ID: US10310376B2
- Status: Granted
- Kind: B2
- Application number: 15/372,622
- Filed: 2016-12-08
- Published: 2017-06-29
- Granted: 2019-06-04
- Earliest claimed: 2015-12-25
- Assignees: Shin-Etsu Chemical Co., Ltd.
- Applicants: Shin-Etsu Chemical Co., Ltd.
- Inventors: Teppei Adachi; Ryosuke Taniguchi; Koji Hasegawa; Kenji Yamada
- Web page: https://patentgrep.com/patent/US10310376B2

## CPC

- C07D 307/77: ortho- or peri-condensed with carbocyclic rings or ring systems
- C07D 307/93: condensed with a ring other than six-membered
- C07D 307/94: spiro-condensed with carbocyclic rings or ring systems, e.g. griseofulvins
- C07D 493/18: Bridged systems
- C07D 493/20: Spiro-condensed systems
- C08F 220/1818: {C13or longer chain (meth)acrylate, e.g. stearyl (meth)acrylate}
- C08F 220/283: {and containing one or more carboxylic moiety in the chain, e.g. acetoacetoxyethyl(meth)acrylate}
- C08F 224/00: Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a heterocyclic ring containing oxygen (cyclic esters of polyfunctional acids C08F218/00; cyclic anhydrides of unsaturated acids C08F220/00, C08F222/00)
- G03F 7/0045: {with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors}
- G03F 7/0046: {with perfluoro compounds, e.g. for dry lithography (G03F7/0048 takes precedence)}
- G03F 7/0382: {the macromolecular compound being present in a chemically amplified negative photoresist composition}
- G03F 7/0397: {the macromolecular compound having an alicyclic moiety in a side chain}
- G03F 7/11: having cover layers or intermediate layers, e.g. subbing layers {(G03F7/091 - G03F7/093, B41N3/03 take precedence)}
- G03F 7/162: {Coating on a rotating support, e.g. using a whirler or a spinner}
- G03F 7/168: {Finishing the coated layer, e.g. drying, baking, soaking}
- G03F 7/2002: {with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image}
- G03F 7/2041: {in the presence of a fluid, e.g. immersion; using fluid cooling means}
- G03F 7/322: {Aqueous alkaline compositions}
- G03F 7/325: {Non-aqueous compositions}
- G03F 7/327: {Non-aqueous alkaline compositions, e.g. anhydrous quaternary ammonium salts}
- G03F 7/38: Treatment before imagewise removal, e.g. prebaking {(G03F7/265 takes precedence)}
- C08F 2800/20: as weight or mass percentages
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

A polymer comprising recurring units containing a specific lactone ring and having an alkyl group on γ-butyrolactone skeleton of fused ring lactone and an alkyl ester substituent group intervening between the lactone structure and the polymer backbone is provided. A resist composition comprising the polymer as base resin is improved in such properties as DOF margin and MEF and quite effective for precise micropatterning.

## Claims

### Claim 1

A polymer comprising recurring units having the formula (1):
wherein R1 is hydrogen or methyl,
R2 is a C1-C20 straight, branched or cyclic divalent hydrocarbon group in which any constituent —CH2— moiety may be replaced by —O— or —C(═O)—,
R3 and R4 are each independently a C1-C15 straight, branched or cyclic alkyl group, R3 and R4 may bond together to form a ring with the carbon atom to which they are attached, a ring-forming combination of R3 and R4 is a C2-C15 straight, branched or cyclic alkylene group,
W is —CH2—, —CH2CH2— or —O—, or two separate —H,
the broken line designates a single bond or divalent organic group bonding the norbornane, bicyclo[2.2.2]octane, 7-oxanorbornane or cyclohexane ring structure to the γ-butyrolactone ring structure, or a structure sharing one or two constituent carbon atoms between these ring structures.

### Claim 2 (depends on 1)

The polymer of claim 1 wherein the recurring units having the formula (1) are recurring units having the formula (2) or (3):
wherein R1 to R4 are as defined above.

### Claim 3 (depends on 1)

The polymer of claim 1, further comprising recurring units having the formula (4):
wherein R1 is as defined above, and X is an acid labile group.

### Claim 4 (depends on 1)

The polymer of claim 1, further comprising recurring units of at least one type selected from recurring units having the formulae (5) to (7):
wherein R1 is as defined above, R5 and R6 are each independently hydrogen or hydroxyl, Y is a substituent group containing a lactone structure different from formula (1) or a substituent group containing a sultone structure, Z is hydrogen, a C1-C15 fluorinated hydrocarbon group, or a C1-C15 fluoroalcohol-containing substituent group.

### Claim 5 (depends on 1)

A resist composition comprising (A) a base resin comprising the polymer of claim 1, (B) a photoacid generator, and (C) a solvent.

### Claim 6 (depends on 5)

The resist composition of claim 5 wherein the photoacid generator (B) comprises a photoacid generator having the formula (B-1):
wherein R7 is a C1-C35 straight, branched or cyclic monovalent hydrocarbon group which may contain an oxygen atom, a nitrogen-containing heterocyclic group, or a group of the formula (i):
(R8)(R9)N—R10— (i)
wherein R8 and R9 are each independently hydrogen or a C1-C20 monovalent hydrocarbon group which may contain a heteroatom, R8 and R9 may bond together to form a ring with the nitrogen atom to which they are attached, R10 is a C1-C20 divalent hydrocarbon group which may contain a heteroatom,
A is hydrogen or trifluoromethyl,
R101, R102 and R103 each independently an optionally substituted C1-C10 straight or branched alkyl, alkenyl or oxoalkyl group, or an optionally substituted C6-C18 aryl, aralkyl or aryloxoalkyl group, any two of R101, R102 and R103 may bond together to form a ring with the sulfur atom to which they are attached.

### Claim 7 (depends on 5)

The resist composition of claim 5 wherein the photoacid generator (B) comprises a photoacid generator having the formula (B-2):
wherein A is hydrogen or trifluoromethyl,
R104, R105 and R106 are each independently hydrogen or a C1-C20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom,
r and s are each independently an integer of 0 to 5, t is an integer of 0 to 4, and
L is a single bond or a C1-C20 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom.

### Claim 8 (depends on 5)

The resist composition of claim 5 wherein the photoacid generator (B) comprises a photoacid generator having the formula (B-3):
wherein R7 is a C1-C35 straight, branched or cyclic monovalent hydrocarbon group which may contain an oxygen atom, a nitrogen-containing heterocyclic group, or a group of the formula (i):
(R8)(R9)N—R10— (i)
wherein R8 and R9 are each independently hydrogen or a C1-C20 monovalent hydrocarbon group which may contain a heteroatom, R8 and R9 may bond together to form a ring with the nitrogen atom to which they are attached, R10 is a C1-C20 divalent hydrocarbon group which may contain a heteroatom,
R101, R102 and R103 are each independently an optionally substituted C1-C10 straight or branched alkyl, alkenyl or oxoalkyl group, or an optionally substituted C6-C18 aryl, aralkyl or aryloxoalkyl group, any two of R101, R102 and R103 may bond together to form a ring with the sulfur atom to which they are attached.

### Claim 9 (depends on 5)

The resist composition of claim 5, further comprising (D) a second polymer different from the polymer (A), the second polymer comprising recurring units of at least one type selected from recurring units having the formulae (D-1) to (D-5):
wherein R1 and W are as defined above,
R11 is each independently hydrogen or a C1-C10 straight, branched or cyclic monovalent hydrocarbon group,
R12 is a single bond or a C1-C5 straight or branched divalent hydrocarbon group,
R13 is each independently hydrogen, a C1-C15 straight, branched or cyclic monovalent hydrocarbon or monovalent fluorinated hydrocarbon group, or an acid labile group, the monovalent hydrocarbon or fluorinated hydrocarbon group represented by R13 may have an ether bond (—O—) or carbonyl moiety (—C(═O)—) intervening in a carbon-carbon bond,
R14 is a C1-C20 straight, branched or cyclic (u+1)-valent hydrocarbon or fluorinated hydrocarbon group,
u is an integer of 1 to 3,
R15 is each independently hydrogen or a group of the formula (ii):
—C(═O)—O—R17 (ii)
wherein R17 is a C1-C20 straight, branched or cyclic monovalent fluorinated hydrocarbon group,
R16 is a C1-C15 straight, branched or cyclic monovalent hydrocarbon or monovalent fluorinated hydrocarbon group which may have an ether bond (—O—) or carbonyl moiety (—C(═O)—) intervening in a carbon-carbon bond.

### Claim 10 (depends on 5)

A pattern forming process comprising the steps of applying the resist composition of claim 5 onto a substrate, prebaking to form a resist film, exposing the resist film to KrF excimer laser, ArF excimer laser, EB or EUV, baking, and developing the exposed resist film in a developer.

### Claim 11 (depends on 10)

The process of claim 10 wherein the exposure step is carried out by immersion lithography using a liquid having a refractive index of at least 1.0 between the resist film and a projection lens.

### Claim 12 (depends on 11)

The process of claim 11, further comprising the step of forming a protective film on the resist film prior to the exposure step, wherein immersion lithography is carried out while the liquid is held between the protective film and the projection lens.

### Claim 13 (depends on 10)

The process of claim 10 wherein the developing step uses the developer comprising an organic solvent to form a negative pattern.