Salt compound, chemically amplified resist composition, and patterning process

Patent metadata

Field	Value
Publication number	US-11435666-B2
Application number	US-201916669780-A
Country	US
Kind code	B2
Filing date	Oct 31, 2019
Priority date	Nov 15, 2018
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A novel salt having an amide bond in its anion structure is provided. A chemically amplified resist composition comprising the salt has advantages including minimal defects and improved values of sensitivity, LWR, MEF and CDU, when processed by lithography using high-energy radiation such as KrF excimer laser, ArF excimer laser, EB or EUV.

First claim

The invention claimed is:

1. A salt compound having the formula (A):

wherein R 1 is a C 1 -C 20 monovalent hydrocarbon group which may contain a heteroatom, R 2 is a C 1 -C 20 divalent hydrocarbon group which may contain a heteroatom, R 3 is hydrogen or a C 1 -C 12 monovalent hydrocarbon group, R 1 and R 3 may bond together to form a ring with the carbon and nitrogen atoms to which they are attached, R f1 , R f2 , R f3 and R f4 are each independently hydrogen, fluorine or trifluoromethyl, at least one of R f1 , R f2 , R f3 and R f4 is fluorine or trifluoromethyl, L 1 is —CO—O—, —O—CO—, —O—CO—O— or —O—, M + is a monovalent organic cation, m is 1, and n is 1.

2. The salt compound of claim 1 wherein R f1 and R f2 are fluorine, R f3 and R f4 are hydrogen.

3. The salt compound of claim 1 wherein R f1 and R f2 are fluorine, R f3 is trifluoromethyl, and R f4 is hydrogen.

4. The salt compound of claim 1 wherein R 1 is a lactone structure-containing group.

5. The salt compound of claim 1 wherein M + is a sulfonium cation having the formula (A1), an iodonium cation having the formula (A2) or an ammonium cation having the formula (A3):

wherein R 11 to R 19 are each independently a C 1 -C 20 monovalent hydrocarbon group which may contain a heteroatom.

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

7. A chemically amplified 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 a phenylene or naphthylene group, 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, sulfonate bond, carbonate bond, lactone ring, sultone ring and carboxylic anhydride.

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

10. The resist composition of claim 7 , further comprising a quencher.

11. The resist composition of claim 10 wherein the quencher contains a compound having the formula (1a) or (1b):

wherein R q1 is hydrogen or a C 1 -C 40 monovalent hydrocarbon group which may contain a heteroatom, excluding the hydrocarbon group in which the hydrogen atom 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.

12. The resist composition of claim 10 wherein the quencher contains an amine compound.

13. The resist composition of claim 7 , further comprising a photoacid generator other than the photoacid generator.

14. The resist composition of claim 13 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 fc3 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 C 1 -C 40 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 is fluorine or trifluoromethyl.

15. The resist composition of claim 7 , further comprising 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.

16. A pattern forming process comprising the steps of applying the chemically amplified resist composition of claim 7 onto a substrate to form a resist film thereon, exposing a selected region of the resist film to KrF excimer laser, ArF excimer laser, EB or EUV, and developing the exposed resist film in a developer.

17. The pattern forming process of claim 16 wherein the developing step uses an alkaline aqueous solution as the developer, thereby forming a positive pattern in which an exposed region of the resist film is dissolved away and an unexposed region of the resist film is not dissolved.

18. The pattern forming process of claim 16 wherein the developing step uses an organic solvent as the developer, thereby forming a negative pattern in which an unexposed region of the resist film is dissolved away and an exposed region of the resist film is not dissolved.

19. The pattern forming process of claim 18 wherein the organic solvent is at least one solvent selected from the group consisting of 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate.

20. The process of claim 16 wherein the exposure step is carried out by immersion lithography while a liquid having a refractive

Assignees

• Shinetsu Chemical Co

Inventors

• Ono Emiko
• Sagehashi Masayoshi
• Fukushima Masahiro
• Kera Yuki

Classifications

• C07D311/00

  Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings · CPC title

• G03F1/48

  Protective coatings · CPC title

• C09D133/08

  Homopolymers or copolymers of acrylic acid esters · CPC title

• G03F1/22

  Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof · CPC title

• C07C381/12

  Sulfonium compounds · CPC title