Onium salt monomer, polymer, chemically amplified resist composition, and pattern forming process

Patent metadata

Field	Value
Publication number	US-2025298314-A1
Application number	US-202519076049-A
Country	US
Kind code	A1
Filing date	Mar 11, 2025
Priority date	Mar 22, 2024
Publication date	Sep 25, 2025
Grant date	—

Abstract

A sulfonium or iodonium salt monomer containing an aromatic sulfonic acid anion containing a polymerizable group of a styrene or vinylnaphthalene structure and an iodized aromatic ring structure is a useful acid generator. A resist composition comprising a polymer comprising repeat units derived from the monomer exhibits a high solvent solubility, high sensitivity and high contrast and forms a small-size pattern with satisfactory lithography properties such as EL, LWR, CDU and DOF.

First claim

1 . An onium salt monomer having the formula (a):

wherein n1 is 0 or 1, n2 is an integer of 0 to 4, n3 is 0 or 1, n4 is an integer of 1 to 4, n5 is an integer of 0 to 4, n4+n5 is from 1 to 4 when n3=0 and from 1 to 6 when n3=1, n6 is 0 or 1, n7 is an integer of 0 to 4, n8 is an integer of 0 to 4, n7+n8 is from 0 to 4 when n6=0 and from 0 to 6 when n6=1,
R A is hydrogen, fluorine, methyl or trifluoromethyl,
R 1 is halogen or a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, a plurality of R 1 may bond together to form a ring with the carbon atoms to which they are attached, when n2=2, 3 or 4,
R 2 is halogen exclusive of iodine or a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, a plurality of R 2 may bond together to form a ring with the carbon atoms to which they are attached, when n5=2, 3 or 4,
R 3 is halogen exclusive of fluorine or a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, a plurality of R 3 may bond together to form a ring with the carbon atoms to which they are attached, when n8=2, 3 or 4,
R F is fluorine, a C 1 -C 6 fluorinated saturated hydrocarbyl group, C 1 -C 6 fluorinated saturated hydrocarbyloxy group, or C 1 -C 6 fluorinated saturated hydrocarbylthio group, a plurality of R F may be identical or different when n7=2, 3 or 4,
L A , L B and L C are each independently a single bond, ether bond, ester bond, amide bond, sulfonate ester bond, sulfonamide bond, carbonate bond or carbamate bond,
X L is a single bond or a C 1 -C 40 hydrocarbylene group which may contain a heteroatom, and
Z + is an onium cation.

2 . The onium salt monomer of claim 1 , having the formula (a1):

wherein n1 to n8, R A , R 1 , R 2 , R 3 , R F , L A , L C and Z + are as defined above.

3 . The onium salt monomer of claim 2 , having the formula (a2):

wherein n1 to n5, R A , R 1 , R 2 , L A , L C and Z + are as defined above.

4 . The onium salt monomer of claim 1 wherein Z + is a sulfonium cation having the formula (cation-1) or iodonium cation having the formula (cation-2):

wherein R ct1 to R ct5 are each independently halogen or a C 1 -C 30 hydrocarbyl group which may contain a heteroatom, R ct1 and R ct2 may bond together to form a ring with the sulfur atom to which they are attached.

5 . A polymer comprising repeat units derived from the onium salt monomer of claim 1 .

6 . The polymer of claim 5 which functions as a polymer-bound acid generator.

7 . The polymer of claim 5 , further comprising repeat units having the formula (b1) or (b2):

wherein R A is each independently hydrogen, fluorine, methyl or trifluoromethyl,
X 1 is a single bond, phenylene group, naphthylene group, *—C(═O)—O—X 11 — or *—C(═O)—NH—X 11 —, the phenylene and naphthylene groups may be substituted with hydroxy, nitro, cyano, a C 1 -C 10 saturated hydrocarbyl moiety which may contain fluorine, C 1 -C 10 alkoxy moiety which may contain fluorine, or halogen, X 11 is a C 1 -C 10 saturated hydrocarbylene group, phenylene group or naphthylene group, the saturated hydrocarbylene group may contain hydroxy, ether bond, ester bond or lactone ring,
X 2 is a single bond, *—C(═O)—O— or *—C(═O)—NH—, * designates a point of attachment to the carbon atom in the backbone,
R 11 is halogen, cyano, hydroxy, nitro, a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, C 1 -C 20 hydrocarbyloxy group which may contain a heteroatom, C 2 -C 20 hydrocarbylcarbonyl group which may contain a heteroatom, C 2 -C 20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or C 2 -C 20 hydrocarbyloxycarbonyl group which may contain a heteroatom,
AL 1 and AL 2 are each independently an acid labile group, and
a is an integer of 0 to 4.

8 . The polymer of claim 5 , further comprising repeat units having the formula (b3):

wherein b1 is 0 or 1, b2 is an integer of 0 to 3 when b1=0 and an integer of 0 to 5 when b1=1,
R A is hydrogen, fluorine, methyl or trifluoromethyl,
X 3 is a single bond, *—C(═O)—O— or *—C(═O)—NH—, * designates a point of attachment to the carbon atom in the backbone,
R 12 and R 13 are each independently hydrogen or a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, R 12 and R 13 may bond together to form a ring with the carbon atom to which they are attached,
R 14 is halogen, hydroxy, cyano, nitro, a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, C 1 -C 20 hydrocarbyloxy group which may contain a heteroatom, C 2 -C 20 hydrocarbyloxycarbonyl group which may contain a heteroatom, C 1 -C 20 hydrocarbylthio group which may contain a heteroatom, or —N(R 14A )(R 14B ), R 14A and R 14B are each independently hydrogen or a C 1 -C 6 hydrocarbyl group, a plurality of R 14 may bond together to form a ring with the carbon atoms on the aromatic ring to which they are attached, when b2 is 2 or more,
X 4 is a single bond, C 1 -C 4 aliphatic hydrocarbylene group, carbonyl group, sulfonyl group or a group obtained by combining the foregoing,
X 5 and X 6 are each independently oxygen or sulfur, with the proviso that X 4 and X 6 are attached to adjacent carbon atoms on the aromatic ring.

9 . The polymer of claim 5 , further comprising repeat units having the formula (c1):

wherein R A is hydrogen, fluorine, methyl or trifluoromethyl,
Y 1 is a single bond, *—C(═O)—O— or *—C(═O)—NH—, * designates a point of attachment to the carbon atom in the backbone,
R 21 is halogen, nitro, cyano, carboxy, a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, C 1 -C 20 hydrocarbyloxy group which may contain a heteroatom, C 2 -C 20 hydrocarbylcarbonyl group which may contain a heteroatom, C 2 -C 20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or C 2 -C 20 hydrocarbyloxycarbonyl group which may contain a heteroatom,
c is an integer of 1 to 4, d is an integer of 0 to 3, and c+d is from 1 to 5.

10 . The polymer of claim 5 , further comprising repeat units having the formula (d1):

wherein R A is hydrogen, fluorine, methyl or trifluoromethyl,
Z 1 is a single bond, phenylene group, naphthylene group, *—C(═O)—O—Z 11 — or *—C(═O)—NH—Z 11 —, the phenylene and naphthylene groups may be substituted with hydroxy, nitro, cyano, a C 1 -C 10 saturated hydrocarbyl moiety which may contain fluorine, C 1 -C 10 alkoxy moiety which may contain fluorine, or halogen, * designates a point of attachment to the carbon atom in the backbone, Z 11 is a C 1 -C 10 saturated hydrocarbylene group, phenylene group or naphthylene group, the saturated hydrocarbylene group may contain hydroxy, ether bond, ester bond or lactone ring,
R 31 is hydrogen or a C 1 -C 20 group containing at least one structure selected from hydroxy other than phenolic hydroxy, cyano, carbonyl, carboxy, ether bond, ester bond, sulfonate ester bond, carbonate bond, lactone ring, sultone ring, a

Assignees

• Shinetsu Chemical Co

Inventors

• Fukushima Masahiro

Classifications

• C07C2603/74

  Adamantanes · CPC title

• G03F7/004

  Photosensitive materials (G03F7/12, G03F7/14 take precedence) · CPC title

• G03F7/2004

  characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light · CPC title

• G03F1/56

  Organic absorbers, e.g. of photo-resists · CPC title

• C07C25/18

  Polycyclic aromatic halogenated hydrocarbons · CPC title