Salt, photoresist composition and method for producing photoresist pattern

1. A photoresist composition which comprises a resin which is soluble in an aqueous alkali solution by action of an acid and a salt represented by formula (I):

wherein Q 1 and Q 2 each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group,

L 1 represents a group represented by any one of formulae (L 1 -1), (L 1 -2) and (L 1 -3)

wherein X 0 represents a single bond,

a C1-C14 divalent aliphatic hydrocarbon group which can have a fluorine atom,

or a group represented by formula (a-1)

where s represents an integer of 0 or 1, X 10 and X 11 each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group, or an oxycarbonyl group, A 10 and A 11 each independently represent a C1-C12 divalent aliphatic hydrocarbon group which can have a fluorine atom, A 12 represents a single bond or a C1-C12 divalent aliphatic hydrocarbon group which can have a fluorine atom,

* represents a binding position to a carbon atom binding to R L ,

X 1 represents —O—* 1 , —NR 3 —* 1 , —O—CO—* 1 , —O—CH 2 —* 1 , —O—CH 2 —CO—O—* 1 or —NR 3 —CH 2 —* 1 where * 1 represents a binding position to W 1 ,

X 2 represents —O—* 2 , —NR 3 —* 2 , —O—CO—* 2 , —O—CH 2 —* 2 , —O—CH 2 —CO—O—* 2 or —NR 3 —CH 2 —* 2 where * 2 represents a binding position to W 2 ,

X 3 represents —O—* 1 , —NR 3 —* 1 , —O—CH 2 —CO—O—* 1 or —O—CH 2 —CO—NR 3 —* 1 where * 1 represents a binding position to W 1 ,

X 4 represents —O—* 2 , —NR 3 —* 2 , —O—CH 2 —CO—O—* 2 or —O—CH 2 —CO—NR 3 —* 2 where * 2 represents a binding position to W 2 ,

X 5 represents —O—* 1 , —NR 3 —* 1 , —O—CO—* 1 , —O—CH 2 —* 1 , or —NR 3 —CH 2 —* 1 where * 1 represents a binding position to W 1 ,

X 6 represents —O—* 2 , —NR 3 —* 2 , —O—CO—* 2 , —O—CH 2 —* 2 or —NR 3 —CH 2 —* 2 where * 2 represents a binding position to W 2 , R 3 represents a hydrogen atom or a C1-C6 alkyl group,

R L represents a hydrogen atom or a C1-C14 aliphatic hydrocarbon group which can have a fluorine atom,

* 0 represents a binding position to a carbon atom binding to C(Q 1 )(Q 2 ), and

m 1 , m 2 , m 3 , m 4 and m 5 each independently represent an integer of 0 to 6,

W 1 and W 2 each independently represent a C3-C36 alicyclic hydrocarbon ring in which a methylene group can be replaced by an oxygen atom, a sulfur atom, —NR 4 —, a sulfonyl group or a carbonyl group, where R 4 represents a hydrogen atom or a C1-C6 alkyl group,

R 1 and R 2 each independently represent a hydroxy group or a C1-C6 alkyl group,

t 1 and t 2 each independently represent an integer of 0 to 2, and

Z + represents an organic cation.

2. The photoresist composition according to claim 1 , wherein Z + is an arylsulfonium cation.

3. The photoresist composition according to claim 1 wherein the resin has a structural unit represented by formula (a1-1)

wherein R a4 represents a hydrogen atom or a methyl group,

R a6 represents a C1-C10 aliphatic hydrocarbon group,

L a1 represents *—O— or *—-O—(CH 2 ) k1 —CO—O— in which * represents a binding position to —CO—, and

k1 represents an integer of 1 to 7, m1 represents an integer of 0 to 14.

4. The photoresist composition according to claim 1 , which further comprises a basic compound.

5. A process for producing a photoresist pattern comprising the steps (1) to (5):

(1) a step of applying the photoresist composition according to claim 1 on a substrate,

(2) a step of forming a photoresist film by conducting drying,

(3) a step of exposing the photoresist film to radiation,

(4) a step of baking the exposed photoresist film, and

(5) a step of developing the baked photoresist film, thereby forming a photoresist pattern.

6. A salt represented by formula (I):

wherein Q 1 and Q 2 each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group,

L 1 represents a group represented by any one of formulae (L 1 -1), (L 1 -2) and (L 1 -3)

wherein X 0 represents a single bond,

a C1-C14 divalent aliphatic hydrocarbon group which can have a fluorine atom,

or a group represented by formula (a-1)

where s represents an integer of 0 or 1, X 10 and X 11 each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group, or an oxycarbonyl group, A 10 and A 11 each independently represent a C1-C12 divalent aliphatic hydrocarbon group which can have a fluorine atom, A 12 represents a single bond or a C1-C12 divalent aliphatic hydrocarbon group which can have a fluorine atom,

* represents a binding position to a carbon atom binding to R L ,

X 1 represents —O—* 1 , —NR 3 —* 1 , —O—CO—* 1 , —O—CH 2 —* 1 , —O—CH 2 —CO—O—* 1 or —NR 3 —CH 2 —* 1 where * 1 represents a binding position to W 1 ,

X 2 represents —O—* 2 , —NR 3 —* 2 , —O—CO—* 2 , —O—CH 2 —* 2 , —O—CH 2 —CO—O—* 2 or —NR 3 —CH 2 —* 2 where * 2 represents a binding position to W 2 ,

X 3 represents —O—* 1 , —NR 3 —* 1 , —O—CH 2 —CO—O—* 1 or —O—CH 2 —CO—NR 3 —* 1 where * 1 represents a binding position to W 1 ,

X 4 represents —O—* 2 , —NR 3 —* 2 , —O—CH 2 —CO—O—* 2 or —O—CH 2 —CO—NR 3 —* 2 where * 2 represents a binding position to W 2 , R 3 represents a hydrogen atom or a C1-C6 alkyl group,

X 5 represents —O—* 1 , —NR 3 —* 1 , —O—CO—* 1 , —O—CH 2 —* 1 , or —NR 3 —CH 2 —* 1 where * 1 represents a binding position to W 1 ,

X 6 represents —O—* 2 , —NR 3 —* 2 , —O—CO—* 2 , —O—CH 2 —* 2 or —NR 3 —CH 2 —* 2 where * 2 represents a binding position to W 2 ,

R L represents a hydrogen atom or a C1-C14 aliphatic hydrocarbon group which can have a fluorine atom,

* 0 represents a binding position to a carbon atom binding to C(Q 1 )(Q 2 ), and

m 1 , m 2 , m 3 , m 4 and m 5 each independently represent an integer of 0 to 6,

W 1 and W 2 each independently represent a C3-C36 alicyclic hydrocarbon ring in which a methylene group can be replaced by an oxygen atom, a sulfur atom, —NR 4 —, a sulfonyl group or a carbonyl group, where R 4 represents a hydrogen atom or a C1-C6 alkyl group,

R 1 and R 2 each independently represent a hydroxy group or a C1-C6 alkyl group,

t 1 and t 2 each independently represent an integer of 0 to 2, and

Z + represents an organic cation.