Radiation-sensitive resin composition, onium salt compound and method for forming resist pattern
A radiation-sensitive resin composition includes a resin including a structural unit having an acid-dissociable group, an onium salt compound represented by formula (1), and a solvent. R 1 is a hydrogen atom or a monovalent group provided that the monovalent group is not a fluoro group or a monovalent organic group containing a fluorine atom. X 1 and X 2 are each independently a single bond, —O—, —S— or —NR′— wherein R′ is a hydrogen atom or a monovalent hydrocarbon group. In a case where X 1 is —NR′—, R 2 is a monovalent organic group or a hydrogen atom. In a case where X 2 is —NR′—, R 3 is a monovalent organic group or a hydrogen atom. In a case where neither X 1 nor X 2 is —NR′—, R 2 and R 3 are each independently a monovalent organic group.
1. A radiation-sensitive resin composition, comprising:
a solvent;
a resin comprising a structural unit having an acid-dissociable group; and
an onium salt compound of formula (1),
wherein:
Z + is a monovalent onium cation;
R 1 is a hydrogen atom or a monovalent group provided that the monovalent group represented by R 1 is not a fluoro group or a monovalent organic group including a fluorine atom;
X 1 and X 2 are each independently a single bond, —O—, —S— or —NR′— where R′ is a hydrogen atom or a monovalent hydrocarbon group, provided that when two R's are present, the two R's are the same or different;
R 2 includes a methylene group directly bonded to X 1 and a cyclic structure directly bonded the methylene group; and
R 3 includes a methylene group directly bonded to X 2 and a cyclic structure directly bonded the methylene group.
2. The radiation-sensitive resin composition according to claim 1 , wherein each of R 2 and R 3 comprises the cyclic structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, a cyclic acetal structure, a cyclic ether structure and a sultone structure.
3. The radiation-sensitive resin composition according to claim 1 , wherein the cyclic structure of at least one of R 2 and R 3 is alicyclic hydrocarbon group.
4. The radiation-sensitive resin composition according to claim 1 , wherein at least one of R 2 and R 3 comprises the cyclic structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, a cyclic acetal structure, a cyclic ether structure and a sultone structure.
5. The radiation-sensitive resin composition according to claim 1 , wherein the cyclic structure of at least one of R 2 and R 3 is aromatic hydrocarbon group.
6. The radiation-sensitive resin composition according to claim 1 , wherein the cyclic structure of each of R 2 and R 3 is an aromatic hydrocarbon group.
7. The radiation-sensitive resin composition according to claim 1 , wherein the monovalent onium cation is a sulfonium cation or an iodonium cation.
8. The radiation-sensitive resin composition according to claim 1 , wherein the radiation-sensitive resin composition forms a resist pattern by exposure to a radioactive ray having a wavelength of 50 nm or less.
9. The radiation-sensitive resin composition according to claim 1 , wherein each of R 2 and R 3 is independently selected from the group consisting of structures,
where each * is a hand bonding to X 1 or X 2 .
10. The radiation-sensitive resin composition according to claim 1 , wherein each of R 2 and R 3 is independently selected from the group consisting of Structures (1-1), (1-2), (1-3), (1-4), (1-5), (1-6), (1-7), (1-8), (1-14), (1-15), (1-16), (1-17), (1-18), (1-19), (1-20), (1-21), (1-22), (1-23) and (1-24),
11. An onium salt compound of formula,
wherein:
Z + is a monovalent onium cation;
R 1 is a hydrogen atom or a monovalent group provided that the monovalent group of R 1 is not a fluoro group or a monovalent organic group including a fluorine atom;
X 1 and X 2 are each independently a single bond, —O—, —S— or —NR′ where R′ is a hydrogen atom or a monovalent hydrocarbon group, provided that when two R's are present, the two R's are the same or different;
R 2 includes a methylene group directly bonded to X 1 and a cyclic structure directly bonded the methylene group; and
R 3 includes a methylene group directly bonded to X 2 and a cyclic structure directly bonded the methylene group.
12. A method for forming a resist pattern, comprising:
applying the radiation-sensitive resin composition of claim 1 on a substrate to form a resist film;
exposing the resist film formed on the substrate; and
developing the resist film after the exposing of the resist film.
13. The method according to claim 12 , wherein the exposing comprises exposing the resist film formed on the substrate to a radioactive ray having a wavelength of 50 nm or less.
14. The method according to claim 12 , wherein each of R 2 and R 3 comprises the cyclic structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, a cyclic acetal structure, a cyclic ether structure and a sultone structure.
15. The method according to claim 12 , wherein the cyclic structure of at least one of R 2 and R 3 is an alicyclic hydrocarbon group.
16. The method according to claim 12 , wherein at least one of R 2 and R 3 comprises the cyclic structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, a cyclic acetal structure, a cyclic ether structure and a sultone structure.
17. The method according to claim 12 , wherein the cyclic structure of at least one of R 2 and R 3 is an aromatic hydrocarbon group.
18. The method according to claim 12 , wherein the cyclic structure of each of R 2 and R 3 is an aromatic hydrocarbon group.
19. The method according to claim 12 , wherein the monovalent onium cation is a sulfonium cation or an iodonium cation.
20. The onium salt compound according to claim 11 , wherein each of R 2 and R 3 is independently selected from the group consisting of structures,
where each * is a hand bonding to X 1 or X 2 .