# US 10,120,279 B2 · Negative resist composition and resist pattern forming process

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- Number: US 10,120,279 B2
- Document ID: US10120279B2
- Status: Granted
- Kind: B2
- Application number: 15/666,757
- Filed: 2017-08-02
- Published: 2018-02-08
- Granted: 2018-11-06
- Earliest claimed: 2016-08-05
- Assignees: Shin-Etsu Chemical Co., Ltd.
- Applicants: Shin-Etsu Chemical Co., Ltd.
- Inventors: Keiichi Masunaga; Satoshi Watanabe; Masaaki Kotake; Kenji Yamada; Masaki Ohashi
- Web page: https://patentgrep.com/patent/US10120279B2

## CPC

- G03F 7/0045: {with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors}
- C07C 69/753: of polycyclic acids
- C07C 303/32: of salts of sulfonic acids
- C07C 309/04: containing only one sulfo group
- C07C 309/06: containing halogen atoms, or nitro or nitroso groups bound to the carbon skeleton
- C07C 309/17: containing carboxyl groups bound to the carbon skeleton
- C07C 309/19: of a saturated carbon skeleton containing rings
- C07C 309/23: of an unsaturated carbon skeleton containing rings other than six-membered aromatic rings
- C07C 309/24: of a carbon skeleton containing six-membered aromatic rings
- C07C 309/29: of non-condensed six-membered aromatic rings
- C07C 309/30: of six-membered aromatic rings substituted by alkyl groups
- C07C 309/31: by alkyl groups containing at least three carbon atoms
- C07C 309/32: containing at least two non-condensed six-membered aromatic rings in the carbon skeleton
- C07C 309/35: Naphthalene sulfonic acids
- C07C 309/44: containing doubly-bound oxygen atoms bound to the carbon skeleton
- C07C 309/58: Carboxylic acid groups or esters thereof
- C08F 212/02: Monomers containing only one unsaturated aliphatic radical
- C08F 220/22: Esters containing halogen
- C08F 220/24: containing perhaloalkyl radicals
- C08F 222/10: Esters
- 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)
- C08F 228/02: by a bond to sulfur
- 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 7/2006: {using coherent light; using polarised light}
- G03F 7/2037: {Exposure with X-ray radiation or corpuscular radiation, through a mask with a pattern opaque to that radiation}
- G03F 7/322: {Aqueous alkaline compositions}
- C08F 220/283: {and containing one or more carboxylic moiety in the chain, e.g. acetoacetoxyethyl(meth)acrylate}
- C08F 220/303: {and one or more carboxylic moieties in the chain}
- C08F 220/382: {and containing oxygen, e.g. 2-sulfoethyl (meth)acrylate}
- 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 7/38: Treatment before imagewise removal, e.g. prebaking {(G03F7/265 takes precedence)}
- 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)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

A negative resist composition comprising (A) a sulfonium compound of betaine type and (B) a polymer is provided. The resist composition is effective for controlling acid diffusion during the exposure step, exhibits a very high resolution during pattern formation, and forms a pattern with minimal LER.

## Claims

### Claim 1

A negative resist composition comprising
(A) a sulfonium compound having the formula (A):
wherein R1, R2 and R3 are each independently a C1-C20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, p and q are each independently an integer of 0 to 5, r is an integer of 0 to 4, in case of p=2 to 5, two adjoining groups R1 may bond together to form a ring with the carbon atoms to which they are attached, in case of q=2 to 5, two adjoining groups R2 may bond together to form a ring with the carbon atoms to which they are attached, and in case of r=2 to 4, two adjoining groups R3 may bond together to form a ring with the carbon atoms to which they are attached, and
(B) a base polymer containing a polymer comprising recurring units having the formula (B1):
wherein RA is hydrogen, fluorine, methyl or trifluoromethyl, R11 is each independently halogen, an optionally halogenated C2-C8 straight, branched or cyclic acyloxy group, optionally halogenated C1-C6 straight, branched or cyclic alkyl group, or optionally halogenated C1-C6 straight, branched or cyclic alkoxy group, A1 is a single bond or a C1-C10 straight, branched or cyclic alkylene group in which an ether bond may intervene in a carbon-carbon bond, s is 0 or 1, w is an integer of 0 to 2, a is an integer in the range: 0≤a≤5+2w−b, and b is an integer of 1 to 3.

### Claim 2 (depends on 1)

The negative resist composition of claim 1 wherein the polymer further comprises recurring units of at least one type selected from units having the formulae (B2), (B3), and (B4):
wherein RA is as defined above, R12 and R13 are each independently a hydroxyl group, halogen atom, acetoxy group, optionally halogenated C2-C8 straight, branched or cyclic acyloxy group, optionally halogenated C1-C8 straight, branched or cyclic alkyl group, optionally halogenated C1-C8 straight, branched or cyclic alkoxy group, or optionally halogenated C2-C8 straight, branched or cyclic alkylcarbonyloxy group, R14 is an acetyl group, acetoxy group, C1-C20 straight, branched or cyclic alkyl group, C1-C20 straight, branched or cyclic alkoxy group, C2-C20 straight, branched or cyclic acyloxy group, C2-C20 straight, branched or cyclic alkoxyalkyl group, C2-C20 alkylthioalkyl group, halogen atom, nitro group, cyano group, sulfinyl group, or sulfonyl group, A2 is a single bond or C1-C10 straight, branched or cyclic alkylene group in which an ether bond may intervene in a carbon-carbon bond, c and d are each independently an integer of 0 to 4, e is an integer of 0 to 5, x is an integer of 0 to 2, and t is 0 or 1.

### Claim 3 (depends on 1)

The negative resist composition of claim 1 wherein the polymer further comprises recurring units having the formula (B5):
wherein RA is as defined above, A3 is a single bond or C1-C10 straight, branched or cyclic alkylene group in which an ether bond may intervene in a carbon-carbon bond, R15 is each independently halogen, an optionally halogenated C2-C8 straight, branched or cyclic acyloxy group, optionally halogenated C1-C6 straight, branched or cyclic alkyl group, or optionally halogenated C1-C6 straight, branched or cyclic alkoxy group, W is hydrogen, a C1-C10 straight, branched or cyclic monovalent aliphatic hydrocarbon group in which an ether, carbonyl or carbonyloxy moiety may intervene in a carbon-carbon bond, or an optionally substituted monovalent aromatic group, Rx and Ry are each independently hydrogen, a C1-C15 alkyl group which may be substituted with a hydroxy or alkoxy moiety, or an optionally substituted monovalent aromatic group, Rx and Ry may bond together to form a ring with the carbon atom to which they are attached, excluding that Rx and Ry are hydrogen at the same time, y is an integer of 0 to 2, u is 0 or 1, f is an integer in the range: 0≤f≤5+2y−g, and g is an integer of 1 to 3.

### Claim 4 (depends on 3)

The negative resist composition of claim 3 wherein the polymer further comprises recurring units of at least one type selected from units having the formulae (a1), (a2), and (a3):
wherein RB is each independently hydrogen or methyl, Z1 is a single bond, phenylene group, —O—Z12—, or —C(═O)—Z11—Z12—, Z11 is —O— or —NH—, Z12 is a C1-C6 straight, branched or cyclic alkylene, C2-C6 straight, branched or cyclic alkenylene or phenylene group, which may contain a carbonyl, ester, ether or hydroxy moiety, Z2 is a single bond or —Z21—C(═O)—O—, Z21 is a C1-C20 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom-containing moiety, Z3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, —O—Z32—, or —C(═O)—Z31—Z32—, Z31 is —O— or —NH—, Z32 is a C1-C6 straight, branched or cyclic alkylene, C2-C6 straight, branched or cyclic alkenylene or phenylene group, which may contain a carbonyl, ester, ether or hydroxy moiety, M− is a non-nucleophilic counter ion, R21, R22, R23, R24, R25, R26, R27, and R28 are each independently a C1-C20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom-containing moiety, or R21 and R22 may bond together to form a ring with the sulfur atom to which they are attached, or any two of R23, R24 and R25 or any two of R26, R27 and R28 may bond together to form a ring with the sulfur atom to which they are attached.

### Claim 5 (depends on 4)

The negative resist composition of claim 4 wherein the polymer comprises recurring units having the formula (B1-1), recurring units having the formula (B5-1), and recurring units having the formula (a2):
wherein RA, RB, Z2, R23, R24, R25, Rx, Ry, W, b, and g are as defined above.

### Claim 6 (depends on 4)

The negative resist composition of claim 4 wherein the base polymer (B) further contains another polymer comprising recurring units having the formula (B1) and recurring units having the formula (B5), but free of recurring units having the formulae (a1), (a2), and (a3).

### Claim 7 (depends on 1)

The negative resist composition of claim 1, further comprising (C) a crosslinker.

### Claim 8 (depends on 3)

The negative resist composition of claim 3, which is free of a crosslinker.

### Claim 9 (depends on 1)

The negative resist composition of claim 1, further comprising (D) a polymer comprising recurring units having the formula (D1) and recurring units of at least one type selected from units having the formulae (D2), (D3), (D4) and (D5):
wherein RB is each independently hydrogen or methyl, RC is each independently hydrogen, fluorine, methyl or trifluoromethyl, R41 is hydrogen or a C1-C5 straight or branched monovalent hydrocarbon group in which a heteroatom may intervene in a carbon-carbon bond, R42 is a C1-C5 straight or branched monovalent hydrocarbon group in which a heteroatom may intervene in a carbon-carbon bond, R43a, R43b, R45a and R45b are each independently hydrogen or a C1-C10 straight, branched or cyclic alkyl group, R44, R46, R47 and R48 are each independently hydrogen, a C1-C15 straight, branched or cyclic monovalent hydrocarbon group or monovalent fluorinated hydrocarbon group, or an acid labile group, with the proviso that an ether or carbonyl moiety may intervene in a carbon-carbon bond in the monovalent hydrocarbon groups or monovalent fluorinated hydrocarbon groups represented by R44, R46, R47 and R48, h is an integer of 1 to 3, i is an integer in the range: 0≤i≤5+2j−h, j is 0 or 1, m is an integer of 1 to 3, X1 is a single bond, —C(═O)—O— or —C(═O)—NH—, and X2 is a C1-C20 straight, branched or cyclic (m+1)-valent hydrocarbon group or fluorinated hydrocarbon group.

### Claim 10 (depends on 1)

The negative resist composition of claim 1, further comprising (E) an acid generator.

### Claim 11 (depends on 1)

A resist pattern forming process comprising the steps of:
applying the negative resist composition of claim 1 onto a processable substrate to form a resist film thereon,
exposing the resist film patternwise to high-energy radiation, and
developing the resist film in an alkaline developer to form a resist pattern.

### Claim 12 (depends on 11)

The process of claim 11 wherein the high-energy radiation is KrF excimer laser radiation, EUV or EB.

### Claim 13 (depends on 11)

The process of claim 11 wherein the processable substrate is a photomask blank.