Sulfonium salt, polymer, resist composition, and patterning process

Patent metadata

Field	Value
Publication number	US-11262653-B2
Application number	US-201816042179-A
Country	US
Kind code	B2
Filing date	Jul 23, 2018
Priority date	Jul 27, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A polymer comprising recurring units derived from a sulfonium salt of specific structure having a polymerizable group is coated to form a resist film which is amenable to precise micropatterning because of improved LWR, CDU and resolution.

First claim

The invention claimed is:

1. A sulfonium salt comprising an anion having the formula (1a) and a sulfonium cation having the formula (1b) or (1C):

wherein R is a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group containing at least one iodine atom, Rf 1 and Rf 2 are each independently hydrogen, fluorine or trifluoromethyl, n is an integer of 0 to 5, and L 1 is a single bond, or a divalent group containing an ether bond, thioether bond, ester bond, sulfonic acid ester bond, carbonate bond or carbamate bond,

wherein A is an organic group having a polymerizable group, R 1 , R 2 and R 3 are each independently a halogen, nitro, cyano, or C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, where a plurality of groups R 1 , R 2 or R 3 are included, two adjacent groups R 1 , R 2 or R 3 may bond together to form a ring with the carbon atoms to which they are attached, X is a single bond, or —O—, —NH—, —S—, —SO—, —SO 2 —, —CO— or —CH 2 —, p is an integer of 0 to 4, q and r are each independently an integer of 0 to 5, q′ and r′ are each independently an integer of 0 to 4.

2. The sulfonium salt of claim 1 wherein the sulfonium cation has the formula (1b-1) or (1c-1):

wherein R 1 , R 2 , R 3 , X, p, q, r, q′ and r′ are as defined above, L 2 is a C 1 -C 20 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom, and R A is each independently hydrogen or methyl.

3. The sulfonium salt of claim 1 wherein the anion has the formula (1a-1):

wherein Rf 1 , Rf 2 , L 1 and n are as defined above, R 4 is a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, s is an integer of 1 to 5, t is an integer of 0 to 4, and 1≤s+t≤5.

4. The sulfonium salt of claim 3 wherein the anion has the formula (1a-2):

wherein R 4 , s and t are as defined above, L 3 is a C 1 -C 20 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom, u and v are each independently 0 or 1.

5. The sulfonium salt of claim 1 wherein R is a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group containing at least two iodine atoms.

6. The sulfonium salt of claim 1 wherein R is a C 6 -C 20 aryl group containing at least one iodine atom.

Assignees

• Shinetsu Chemical Co

Inventors

• Ohashi Masaki
• Hatakeyama Jun
• Adachi Teppei

Classifications

• C07D339/08

  Six-membered rings · CPC title

• C08F12/22

  Oxygen · CPC title

• C07D327/08

  [b,e]-condensed with two six-membered carbocyclic rings · CPC title

• C07D327/06

  Six-membered rings · CPC title

• C08L41/00

  Compositions of homopolymers or 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 bond to sulfur or by a heterocyclic ring containing sulfur; Compositions of derivatives of such polymers · CPC title