# US 12,222,649 B2 · Positive resist composition and pattern forming process

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- Number: US 12,222,649 B2
- Document ID: US12222649B2
- Status: Granted
- Kind: B2
- Application number: 17/570,612
- Filed: 2022-01-07
- Published: 2022-08-04
- Granted: 2025-02-11
- Earliest claimed: 2021-01-27
- Assignees: Shin-Etsu Chemical Co., Ltd.
- Applicants: Shin-Etsu Chemical Co., Ltd.
- Inventors: Jun Hatakeyama; Koji Hasegawa
- Web page: https://patentgrep.com/patent/US12222649B2

## CPC

- G03F 7/0397: {the macromolecular compound having an alicyclic moiety in a side chain}
- 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 7/0392: {the macromolecular compound being present in a chemically amplified positive photoresist composition}
- G03F 7/2006: {using coherent light; using polarised light}
- G03F 7/322: {Aqueous alkaline compositions}
- G03F 7/38: Treatment before imagewise removal, e.g. prebaking {(G03F7/265 takes precedence)}
- G03F 7/40: Treatment after imagewise removal, e.g. baking
- 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 positive resist composition comprising a base polymer comprising repeat units having the structure of a sulfonium salt of a fluorinated phenol exhibits a high sensitivity, high resolution, low edge roughness and small size variation, and forms a pattern of good profile after exposure and development.

## Claims

### Claim 1

A positive resist composition comprising a base polymer comprising repeat units (a) having the structure of a sulfonium salt of a fluorinated phenol compound; wherein the repeat units (a) have the formula (a):
wherein RA is hydrogen or methyl,
X1 is, an ester bond, ether bond, phenylene group or naphthylene group,
X2 is a single bond, a phenylene group, or a C1-C12 saturated hydrocarbylene group which may contain an ether bond, ester bond, amide bond, lactone ring or sultone ring,
X3 is a single bond, ester bond or ether bond,
Rf is a fluorine atom, trifluoromethyl, trifluoromethoxy, or trifluoromethylthio group,
R1 is a C1-C4 alkyl group,
R2 to R4 are each independently a halogen or a C1-C20 hydrocarbyl group which may contain a heteroatom, R2 and R3 may bond together to form a ring with the sulfur atom to which they are attached,
m is an integer of 1 to 4, n is an integer of 0 to 3, and m+n is from 1 to 4.

### Claim 2 (depends on 1)

The positive resist composition of claim 1 wherein the base polymer further comprises repeat units (b1) having a carboxy group in which the hydrogen is substituted by an acid labile group and/or repeat units (b2) having a phenolic hydroxy group in which the hydrogen is substituted by an acid labile group.

### Claim 3 (depends on 2)

The positive resist composition of claim 2 wherein the repeat units (b1) have the formula (b1) and the repeat units (b2) have the formula (b2):
wherein RA is each independently hydrogen or methyl, Y1 is a single bond, phenylene, naphthylene, or a C1-C12 linking group containing an ester bond, ether bond or lactone ring, Y2 is a single bond, ester bond or amide bond, Y3 is a single bond, ether bond or ester bond, R11 and R12 are each independently an acid labile group, R13 is fluorine, trifluoromethyl, cyano or a C1-C6 saturated hydrocarbyl group, R14 is a single bond or a C1-C6 alkanediyl group which may contain an ether bond or ester bond, a is 1 or 2, b is an integer of 0 to 4, and a+b is from 1 to 5.

### Claim 4 (depends on 1)

The positive resist composition of claim 1 wherein the base polymer further comprises repeat units (c) containing an adhesive group selected from the group consisting of hydroxy, carboxy, lactone ring, carbonate bond, thiocarbonate bond, carbonyl, cyclic acetal, ether bond, ester bond, sulfonic ester bond, cyano, amide bond, —O—C(═O)—S—, and —O—C(═O)—NH—.

### Claim 5 (depends on 1)

The positive resist composition of claim 1 wherein the base polymer further comprises repeat units of at least one type selected from repeat units having the formulae (d1) to (d3):
wherein RA is each independently hydrogen or methyl,
Z1 is a single bond, a C1-C6 aliphatic hydrocarbylene group, phenylene, naphthylene or a C7-C18 group obtained by combining the foregoing, or —O-Z11-, —C(═O)—O—Z11- or —C(═O)—NH—Z11-, Z11 is a C1-C6 aliphatic hydrocarbylene group, phenylene, naphthylene or a C7-C18 group obtained by combining the foregoing, which may contain a carbonyl moiety, ester bond, ether bond or hydroxy moiety,
Z2 is a single bond or ester bond,
Z3 is a single bond, -Z31-C(═O)—O—, -Z31-O— or -Z31-O—C(═O)—, Z31 is a C1-C12 aliphatic hydrocarbylene group, phenylene or a C7-C18 group obtained by combining the foregoing, which may contain a carbonyl moiety, ester bond, ether bond, bromine or iodine,
Z4 is methylene, 2,2,2-trifluoro-1,1-ethanediyl or carbonyl,
Z5 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, trifluoromethyl-substituted phenylene, —O-Z51-, —C(═O)—O—Z51-, or —C(—O)—NH-Z51-, Z31 is a C1-C6 aliphatic hydrocarbylene group, phenylene, fluorinated phenylene, or trifluoromethyl-substituted phenylene group, which may contain a carbonyl moiety, ester bond, ether bond, halogen or hydroxy moiety,
R21 to R28 are each independently halogen or a C1-C20 hydrocarbyl group which may contain a heteroatom, a pair of R23 and R24, or R26 and R27 may bond together to form a ring with the sulfur atom to which they are attached, and
M− is a non-nucleophilic counter ion.

### Claim 6 (depends on 1)

The positive resist composition of claim 1, further comprising an acid generator.

### Claim 7 (depends on 1)

The positive resist composition of claim 1, further comprising an organic solvent.

### Claim 8 (depends on 1)

The positive resist composition of claim 1, further comprising a quencher.

### Claim 9 (depends on 1)

The positive resist composition of claim 1, further comprising a surfactant.

### Claim 10 (depends on 1)

A pattern forming process comprising the steps of applying the positive resist composition of claim 1 onto a substrate to form a resist film thereon, exposing the resist film to high-energy radiation, and developing the exposed resist film in a developer.

### Claim 11 (depends on 10)

The pattern forming process of claim 10 wherein the high-energy radiation is i-line, KrF excimer laser, ArF excimer laser, EB, or EUV of wavelength 3 to 15 nm.

### Claim 12 (depends on 1)

The positive resist composition of claim 1, wherein m is 4.

### Claim 13 (depends on 1)

The positive resist composition of claim 1, wherein the base polymer comprises
repeat units (a),
repeat units (b1) having a carboxy group in which the hydrogen is substituted by an acid labile group and/or repeat units (b2) having a phenolic hydroxy group in which the hydrogen is substituted by an acid labile group,
repeat units (c) containing an adhesive group selected from the group consisting of hydroxy, carboxy, lactone ring, carbonate bond, thiocarbonate bond, carbonyl, cyclic acetal, ether bond, ester bond, sulfonic ester bond, cyano, amide bond, —O—C(—O)—S—, and —O—C(═O)—NH—,
repeat units (d) of at least one type selected from repeat units (d1) to (d3) having the formulae (d1) to (d3),
repeat units (e) which are free of an amino group and contain iodine, and
repeat units (f) which are derived from styrene, vinylnaphthalene, indene, acenaphthylene, coumarin, and coumarone,
wherein a fraction of repeat units (a), (b1), (b2), (c), (d1), (d2), (d3), (e) and (f) in the base polymer is 0.01≤a≤0.7, 0≤b1≤0.7, 0≤b2≤0.7, 0≤b1+b2≤0.7, 0≤c≤0.7, 0≤d1≤0.3, 0≤d2≤0.3, 0≤d3≤0.3, 0≤d1+d2+d3≤0.3, 0≤e≤0.3, 0≤f≤0.3, and a+b1+b2+c+d1+d2+d3+e+f=1.0,
wherein RA is each independently hydrogen or methyl,
Z1 is a single bond, a C1-C6 aliphatic hydrocarbylene group, phenylene, naphthylene or a C7-C18 group obtained by combining the foregoing, or —O-Z11-, —C(═O)—O—Z11- or —C(═O)—NH—Z11-, Z11 is a C1-C6 aliphatic hydrocarbylene group, phenylene, naphthylene or a C7-C18 group obtained by combining the foregoing, which may contain a carbonyl moiety, ester bond, ether bond or hydroxy moiety,
Z2 is a single bond or ester bond,
Z3 is a single bond, -Z31-C(═O)—O—, -Z31-O— or -Z31-O—C(═O)—, Z31 is a C1-C12 aliphatic hydrocarbylene group, phenylene or a C7-C18 group obtained by combining the foregoing, which may contain a carbonyl moiety, ester bond, ether bond, bromine or iodine,
Z4 is methylene, 2,2,2-trifluoro-1,1-ethanediyl or carbonyl,
Z5 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, trifluoromethyl-substituted phenylene, —O-Z51-, —C(—O)—O-Z51-, or —C(═O)—NH—Z51-, Z51 is a C1-C6 aliphatic hydrocarbylene group, phenylene, fluorinated phenylene, or trifluoromethyl-substituted phenylene group, which may contain a carbonyl moiety, ester bond, ether bond, halogen or hydroxy moiety,
R21 to R28 are each independently halogen or a C1-C20 hydrocarbyl group which may contain a heteroatom, a pair of R23 and R24, or R26 and R27 may bond together to form a ring with the sulfur atom to which they are attached, and
M− is a non-nucleophilic counter ion.