Sulfonium salt, resist composition and resist pattern forming process

Patent metadata

Field	Value
Publication number	US-9604921-B2
Application number	US-201514861303-A
Country	US
Kind code	B2
Filing date	Sep 22, 2015
Priority date	Sep 25, 2014
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A sulfonium salt of formula (0-1) is provided wherein W is alkylene or arylene, R 01 is a monovalent hydrocarbon group, m is 0, 1 or 2, k is an integer: 0≦k≦5+4m, R 101 , R 102 and R 103 are a monovalent hydrocarbon group, or at least two of R 101 , R 102 and R 103 may bond together to form a ring with the sulfur atom, and L is a single bond, ester, sulfonic acid ester, carbonate or carbamate bond. A resist composition comprising the sulfonium salt as PAG exhibits a very high resolution when processed by EB and EUV lithography. A pattern with minimal LER is obtainable.

First claim

The invention claimed is:

1. A resist composition comprising:
a sulfonium salt having the general formula (1):

wherein R 01 is a C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom,
m is an integer of 0 to 2, k is an integer satisfying 1≦k≦5+4m,
R 101 , R 102 and R 103 are each independently a C 1 -C 20 straight or C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom, or at least two of R 101 , R 102 and R 103 may bond together to form a ring with the sulfur atom,
L is an ester, sulfonic acid ester, carbonate or carbamate bond,
R 02 is a C 1 -C 10 straight or C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom,
n is an integer of 0 to 2, and p is an integer satisfying 0≦p≦4+4n; and
a polymer comprising recurring units having the general formula (U-1):

wherein q is 0 or 1, r is an integer of 0 to 2, R 1 is hydrogen, fluorine, methyl or trifluoromethyl, R 2 is each independently hydrogen or C 1 -C 6 alkyl group, B 1 is a single bond or a C 1 -C 10 alkylene group which may contain an ether bond, a is an integer satisfying a≦5+2r−b, and b is an integer of 1 to 3;
wherein the polymer further comprises recurring units having the general formula (U-3) and/or (U-4):

wherein f is an integer of 0 to 6, R 3 is each independently hydrogen, or a C 1 -C 6 alkyl, primary or secondary alkoxy, or C 1 -C 7 alkylcarbonyloxy group which may be substituted with halogen, g is an integer of 0 to 4, and R 4 is each independently hydrogen, or a C 1 -C 6 alkyl, primary or secondary alkoxy, or C 1 -C 7 alkylcarbonyloxy group which may be substituted with halogen.

2. The resist composition of claim 1 which is a chemically amplified positive tone resist composition, the polymer comprising recurring units adapted to be decomposed under the action of acid to increase the solubility in alkaline developer.

3. The resist composition of claim 2 wherein the recurring unit adapted to be decomposed under the action of acid to increase the solubility in alkaline developer has the general formula (U-2):

wherein s is 0 or 1, t is an integer of 0 to 2, R 1 , R 2 and B 1 are as defined above, c is an integer satisfying c≦5+2t−e, d is 0 or 1, e is an integer of 1 to 3, X is an acid labile group when e=1, X is hydrogen or an acid labile group when e=2 or 3, with at least one Y being an acid labile group.

4. The resist composition of claim 1 which is a chemically amplified negative tone resist composition, the polymer comprising, in addition to the recurring units having formula (U-1), recurring units having the general formula (UN-2):

wherein R 1 and B 1 are as defined above,
Z is hydrogen, or a C 1 -C 20 straight, branched or cyclic alkyl, C 2 -C 20 hydroxyalkyl, C 2 -C 20 alkoxyalkyl, C 2 -C 20 alkylthioalkyl, halogen, nitro, cyano, sulfinyl, or sulfonyl group,
Y is a C 1 -C 20 alkyl or C 1 -C 20 acyl group, h is an integer of 0 to 4, i is an integer of 0 to 5, u is 0 or 1, and v is an integer of 0 to 2.

5. The resist composition of claim 4 , further comprising a crosslinker.

6. The resist composition of claim 1 wherein the anion moiety in the sulfonium salt is selected from the group consisting of the following formulae:

7. The resist composition of claim 1 wherein n is 0.

8. The resist composition of claim 1 wherein k is an integer of 1 to 3.

9. A resist composition comprising:
a sulfonium salt having the general formula (1):

wherein R 01 is a C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom,
m is an integer of 0 to 2, k is an integer satisfying 1≦k≦5+4m,
R 101 , R 102 and R 103 are each independently a C 1 -C 20 straight or C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom, or at least two of R 101 , R 102 and R 103 may bond together to form a ring with the sulfur atom,
L is an ester, sulfonic acid ester, carbonate or carbamate bond,
R 02 is a C 1 -C 10 straight or C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom,
n is an integer of 0 to 2, and p is an integer satisfying 0≦p≦4+4n; and
at least one of basic compounds having the general formulae (7) to (9):

wherein R 12 and R 13 each are a C 1 -C 20 straight, branched or cyclic alkyl, C 6 -C 20 aryl, C 7 -C 20 aralkyl, C 2 -C 20 hydroxyalkyl, C 2 -C 20 alkoxyalkyl, C 2 -C 20 acyloxyalkyl, or C 2 -C 20 alkylthioalkyl group, or R 12 and R 13 may bond together to form a cyclic structure with the nitrogen atom to which they are attached,
R 14 is hydrogen, a C 1 -C 20 straight, branched or cyclic alkyl, C 6 -C 20 aryl, C 7 -C 20 aralkyl, C 2 -C 20 hydroxyalkyl, C 2 -C 20 alkoxyalkyl, C 2 -C 20 acyloxyalkyl, or C 2 -C 20 alkylthioalkyl group, or halogen,
R 15 is a single bond, a C 1 -C 20 straight, branched or cyclic alkylene or C 6 -C 20 arylene group,
R 16 is an optionally substituted, C 1 -C 20 straight or branched alkylene group which may contain at least one carbonyl, ether, ester or sulfide bond between two carbon atoms thereof, and
R 17 is a C 1 -C 20 straight, branched or cyclic alkylene or C 6 -C 20 arylene group.

10. A pattern forming process comprising the steps of applying a resist composition onto a processable substrate to form a resist film, exposing patternwise the resist film to high-energy radiation, and developing in an alkaline developer to form a resist pattern;
wherein the resist composition comprises a sulfonium salt having the general formula (1):

wherein R 01 is a C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom,
m is an integer of 0 to 2, k is an integer satisfying 1≦k≦5+4m,
R 101 , R 102 and R 103 are each independently a C 1 -C 20 straight or C 3 -C 20 branched or cyclic monovalent hydrocarbon group which may be substituted with or separated by a heteroatom, or at least two of R 101 , R 102 and R 103 may bond together to form a ring with the sulfur atom,
L is an ester, sulfonic acid ester, carbonate or carbamate bond,
R 02 is a C 1 -C 10 straight or C 3 -C 20 branched or cyclic monovalent

Assignees

• Shinetsu Chemical Co

Inventors

• Domon Daisuke
• Watanabe Satoshi
• Masunaga Keiichi
• Fukushima Masahiro

Classifications

• C07D335/16

  Oxygen atoms, e.g. thioxanthones · CPC title

• C07C2101/08

  Chemistry & Metallurgy · mapped topic

• G03F7/0045 Primary

  with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors · CPC title

• C07C309/73

  to carbon atoms of non-condensed six-membered aromatic rings · CPC title

• C07C309/42

  having the sulfo groups bound to carbon atoms of non-condensed six-membered aromatic rings · CPC title