Carboxylic acid onium salt, chemically amplified resist composition, and pattern forming process

Patent metadata

Field	Value
Publication number	US-10120278-B2
Application number	US-201715488774-A
Country	US
Kind code	B2
Filing date	Apr 17, 2017
Priority date	Apr 28, 2016
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

A carboxylic acid onium salt of formula (1) exerts a satisfactory acid diffusion control (or quencher) function. A resist composition comprising the carboxylic acid onium salt can be processed by DUV or EUV lithography to form a resist pattern with improved resolution, reduced LWR and minimal defects after development.

First claim

The invention claimed is:

1. A carboxylic acid onium salt having the formula (1):

wherein R 0 is hydrogen, or a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom,
R 1 and R 2 are each independently hydrogen, or a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a hydroxyl moiety, cyano moiety, carbonyl moiety, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sultone ring, or carboxylic anhydride, or R 1 and R 2 may bond together to form a ring with the carbon atom to which they are attached,
R f1 and R f2 are each independently fluorine or a C 1 -C 6 perfluoroalkyl group,
L A is a single bond or forms an ester bond, sulfonate bond, carbonate bond or carbamate bond with the vicinal oxygen atom,
Z + is a sulfonium cation having the formula (2) or an iodonium cation having the formula (3):

wherein R 11 , R 12 and R 13 are each independently a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, any two of R 11 , R 12 and R 13 may bond together to form a ring with the sulfur atom in the formula, R 14 and R 15 are each independently a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom.

2. The onium salt of claim 1 wherein R f1 and R f2 are trifluoromethyl.

3. The onium salt of claim 1 wherein Z + is a sulfonium cation of formula (2).

4. The onium salt of claim 1 wherein L A is a single bond or forms a sulfonate bond with the vicinal oxygen atom.

5. The onium salt of claim 1 wherein L A is a single bond and R 0 is hydrogen.

6. The onium salt of claim 1 wherein the anion moiety of the onium salt is selected from the group consisting of the following formulae:

7. An acid diffusion inhibitor comprising the carboxylic acid onium salt of claim 1 .

8. A chemically amplified resist composition comprising (A) the acid diffusion inhibitor of claim 7 , (B) a base resin, (C) a photoacid generator, and (D) an organic solvent, wherein
said base resin contains a polymer comprising recurring units having the formula (a) and recurring units having the formula (b):

wherein R A is hydrogen, methyl or trifluoromethyl, Z A is a single bond, phenylene, naphthylene or (backbone)—C(═O)—O—Z′—, Z′ is a C 1 -C 10 straight, branched or cyclic alkylene group which may contain a hydroxyl moiety, ether bond, ester bond, or lactone ring, or a phenylene or naphthylene group, X A is an acid labile group, and Y A is hydrogen or a polar group having at least one structure selected from the group consisting of hydroxyl, cyano, carbonyl, carboxyl, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sultone ring, and carboxylic anhydride.

9. The resist composition of claim 8 wherein said polymer further comprises recurring units of at least one type selected from recurring units having the formulae (c1) to (c3):

wherein R A is as defined above,
R 21 is a single bond, phenylene, —O—R 31 —, or —C(═O)—Z 22 —R 31 —, Z 22 is —O— or —NH—, R 31 is a C 1 -C 6 straight, branched or cyclic alkylene group, C 2 -C 6 straight, branched or cyclic alkenylene group or phenylene group, which may contain a carbonyl (—CO—), ester (—COO—), ether (—O—) or hydroxyl moiety,
L B is a single bond or —Z 33 —C(═O)—O—, Z 33 is a C 1 -C 20 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom,
Z 11 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, —O—R 32 —, or —C(═O)—Z 44 —R 32 —, Z 44 is —O— or —NH—, R 32 is a C 1 C 6 straight, branched or cyclic alkylene, C 2 -C 6 straight, branched or cyclic alkenylene or phenylene group, which may contain a carbonyl, ester, ether or hydroxyl moiety,
R 22 to R 26 are each independently a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, or any two of R 21 , R 22 and R 23 may bond together to form a ring with the sulfur atom in the formula, any two of R 24 , R 25 and R 26 may bond together to form a ring with the sulfur atom in the formula, and
M − is a non-nucleophilic counter ion.

10. The resist composition of claim 8 wherein component (C) is a photoacid generator having the formula (4) or (5):

wherein R 101 , R 102 and R 103 are each independently a C 1 -C 20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, any two of R 101 , R 102 and R 103 may bond together to form a ring with the sulfur atom to which they are attached, and X − is an anion selected from the formulae (4A) to (4D):

wherein R fa , R fb1 , R fb2 , R fc1 , R fc2 , and R fc3 are each independently fluorine or a C 1 -C 40 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, R fb1 and R fb2 , or R fc1 and R fc2 may bond together to form a ring with the carbon atoms to which they are attached and the carbon atom therebetween, R fd is a C 1 -C 40 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom,

wherein R 104 and R 105 are each independently a C 1 -C 30 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, R 106 is a C 1 -C 30 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom, any two of R 104 , R 105 and R 106 may bond together to form a ring with the sulfur atom to which they are attached, L C is a single bond, ether bond, or a C 1 -C 20 straight, branched or cyclic divalent hydrocarbon group which may contain a heteroatom, X 1 , X 2 , X 3 and X 4 are each independently hydrogen, fluorine or trifluoromethyl, with the proviso that at least one of X 1 , X 2 , X 3 and X 4 is a substituent other than hydrogen, and k is an integer of 1 to 3.

11. The resist composition of claim 8 , further comprising (E) a nitrogen-containing compound.

12. The resist composition of claim 8 , further comprising (F) a surfactant which is insoluble or substantially insoluble in water and soluble in alkaline developer and/or a surfactant which is insoluble or substantially insoluble in water and alkaline developer.

13. A pattern forming process comprising the steps of applying the chemically amplified resist composition of claim 8 onto a substrate, prebaking to form a resist film, exposing the resist film to KrF excimer laser, ArF excimer laser, EB or EUV through a photomask, baking, and developing the exposed resist film in a developer.

Assignees

• Shinetsu Chemical Co

Inventors

• Fukushima Masahiro
• Katayama Kazuhiro

Classifications

• C07C2601/14

  The ring being saturated · CPC title

• G03F7/11

  having cover layers or intermediate layers, e.g. subbing layers {(G03F7/091 - G03F7/093, B41N3/03 take precedence)} · CPC title

• G03F7/168

  Finishing the coated layer, e.g. drying, baking, soaking · CPC title

• G03F7/70025

  by lasers · CPC title

• G03F7/38

  Treatment before imagewise removal, e.g. prebaking {(G03F7/265 takes precedence)} · CPC title