Onium salt, chemically amplified resist composition, and patterning process

Patent metadata

Field	Value
Publication number	US-11333974-B2
Application number	US-201916660081-A
Country	US
Kind code	B2
Filing date	Oct 22, 2019
Priority date	Oct 24, 2018
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A novel onium salt and a resist composition comprising the same as a PAG are provided. When processed by photolithography using KrF or ArF excimer laser, EB or EUV, the resist composition is reduced in acid diffusion and improved in exposure latitude, MEF, and LWR.

First claim

The invention claimed is:

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

wherein Z is a monocyclic or polycyclic group having a lactam structure,
Rf 1 to Rf 4 are each independently hydrogen, fluorine or trifluoromethyl, at least one of Rf 1 to Rf 4 being fluorine or trifluoromethyl,
R 1 is hydrogen or a C 1 -C 20 monovalent hydrocarbon group which may contain a heteroatom,
R 2 is a C 1 -C 20 monovalent hydrocarbon group which may contain a heteroatom,
L 1 , L 2 and L 3 are each independently a single bond, ether bond, ester bond, sulfonic acid ester bond, carbonate bond or carbamate bond,
L 4 is an ether bond, ester bond, sulfonic acid ester bond, carbonate bond or carbamate bond,
X 1 is a single bond or a C 1 -C 40 divalent hydrocarbon group which may contain a heteroatom,
n 1 is an integer of 0 to 6, with the proviso that R 1 and R 2 may bond together to form a ring structure when n 1 is 1 and R 1 is not hydrogen, and two R 1 may bond together to form a ring structure when n 1 is an integer of at least 2 and R 1 is not hydrogen, and
Q + is an onium cation.

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

wherein Z, Rf 1 to Rf 4 , R 1 , R 2 , L 1 to L 3 , X 1 , n 1 and Q + are as defined above.

3. The onium salt of claim 2 , having any one of the formulae (1a) to (1c):

wherein Rf 1 to Rf 4 , R 1 , R 2 , L 1 to L 3 , X 1 , n 1 and Q + are as defined above, X is —CH 2 —, —CH 2 CH 2 —, —O—, —S— or two separate —H, and n 2 is an integer of 1 to 4.

4. The onium salt of claim 3 wherein the onium salts having formulae (1a) to (1c) are represented by the formulae (1aa) to (1cc), respectively:

wherein R 1 , R 2 , L 1 to L 3 , X, X 1 , n 1 , n 2 , and Q + are as defined above, and R f is hydrogen or trifluoromethyl.

5. The onium salt of claim 1 wherein Q −1 is a sulfonium cation having the formula (2a) or an iodonium cation having the formula (2b):

wherein R 11 to R 15 are each independently a C 1 -C 20 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 to which they are attached.

6. A photoacid generator comprising the onium salt of claim 1 .

7. A resist composition comprising the photoacid generator of claim 6 .

8. The resist composition of claim 7 , further comprising a base resin containing a polymer comprising recurring units having the formula (a) and recurring units having the formula (b):

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

9. The resist composition of claim 7 wherein the polymer further comprises recurring units of at least one type selected from recurring units having the formulae (c1) to (c3):

wherein R A is each independently hydrogen, fluorine, methyl or trifluoromethyl,
Z 1 is a single bond, phenylene, —O—Z 11 —, —C(═O)—O—Z 11 — or —C(═O)—NH—Z 11 —, Z 11 is a C 1 -C 20 alkanediyl group, C 2 -C 20 alkenediyl group or phenylene group, which may contain a carbonyl moiety, ester bond, ether bond or hydroxyl moiety,
Z 2 is a single bond or —Z 21 —C(═O)—O—, Z 21 is a C 1 -C 20 divalent hydrocarbon group which may contain a heteroatom,
Z 3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, —O—Z 31 —, —C(═O)—O—Z 31 — or —C(═O)—NH—Z 31 —, Z 31 is a C 1 -C 6 alkanediyl group, C 2 -C 6 alkenediyl group or phenylene group, which may contain a carbonyl moiety, ester bond, ether bond or hydroxyl moiety,
R 21 and R 22 are each independently a C 1 -C 20 monovalent hydrocarbon group which may contain a heteroatom, R 21 and R 22 may bond together to form a ring with the sulfur atom to which they are attached,
M − is a non-nucleophilic counter ion, and
A + is a sulfonium or iodonium cation.

10. The resist composition of claim 7 , further comprising an organic solvent.

11. The resist composition of claim 7 , further comprising another photoacid generator.

12. The resist composition of claim 11 wherein the other photoacid generator has the formula (3) or (4):

wherein R 101 , R 102 and R 103 are each independently a C 1 -C 20 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 following formulae (3A) to (3D):

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

wherein R 201 and R 202 are each independently a C 1 -C 30 monovalent hydrocarbon group which may contain a heteroatom, R 203 is a C 1 -C 30 divalent hydrocarbon group which may contain a heteroatom, any two of R 201 , R 202 and R 203 may bond together to form a ring with the sulfur atom to which they are attached, L A is a single bond, ether bond or a C 1 -C 20 divalent hydrocarbon group which may contain a heteroatom, X a , X b , X c and X d are each independently hydrogen, fluorine or trifluoromethyl, at least one of X a , X b , X c and X d being fluorine or trifluoromethyl.

13. The resist composition of claim 7 , further comprising a compound having the formula (5) or (6):
R q1 —SO 3 − Mq +   (5)

R q2 —CO 2 − Mq +   (6)

wherein R q1 is hydrogen or a monovalent hydrocarbon group which may contain a heteroatom, exclusive of the group wherein hydrogen bonded to the carbon atom at α-position relative to the sulfo group is substituted by fluorine or fluoroalkyl, R q2 is hydrogen or a C 1 -C 40 monovalent hydrocarbon group which may contain a heteroatom, and Mq + is an onium cation.

14. The resist composition of claim 7 , further comprising an amine compound.

15. The resist composition of claim 7 , further com

Assignees

• Shinetsu Chemical Co

Inventors

• Fukushima Masahiro

Classifications

• C07D405/12

  linked by a chain containing hetero atoms as chain links · CPC title

• G03F7/2053

  using a laser (ablative removal B41C) · CPC title

• C07D333/46

  substituted on the ring sulfur atom · CPC title

• C07C381/12 Primary

  Sulfonium compounds · CPC title

• G03F7/0045 Primary

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