A salt represented by formula (I): ##STR00001##
wherein Q.sup.1 and Q.sup.2 each independently represent a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, R.sup.1 and R.sup.2 each independently represent a hydrogen atom, a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, z represents an integer of 0 to 6, X.sup.1 represents *—O—, *—CO—O— or *—O—CO—, * represents a binding site to CR.sup.1R.sup.2 or CQ.sup.1Q.sup.2, L.sup.1 represents a C.sub.1 to C.sub.6 alkanediyl group, R.sup.3 represents a C.sub.5 to C.sub.18 alicyclic hydrocarbon group in which a hydrogen atom may be replaced by a hydroxy group, and in which a methylene group may be replaced by an oxygen atom or a carbonyl group, and which alicyclic hydrocarbon group may have a cyclic ketal structure optionally having a fluorine atom; and Z.sup.+ represents an organic cation.

A salt represented by formula (I): ##STR00001##
wherein Q.sup.1 and Q.sup.2 each independently represent a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, R.sup.1 and R.sup.2 each independently represent a hydrogen atom, a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, z represents an integer of 0 to 6, X.sup.1 represents *—O—, *—CO—O— or *—O—CO—, * represents a binding site to CR.sup.1R.sup.2 or CQ.sup.1Q.sup.2, L.sup.1 represents a C.sub.1 to C.sub.6 alkanediyl group, R.sup.3 represents a C.sub.5 to C.sub.18 alicyclic hydrocarbon group in which a hydrogen atom may be replaced by a hydroxy group, and in which a methylene group may be replaced by an oxygen atom or a carbonyl group, and which alicyclic hydrocarbon group may have a cyclic ketal structure optionally having a fluorine atom; and Z.sup.+ represents an organic cation.

A sulfonic acid derivative, wherein the sulfonic acid derivative is represented by the following general formula (1):

R.sup.1COOCH.sub.2CH.sub.2CFHCF.sub.2SO.sub.3.sup.−M.sup.+  (1)

where: R.sup.1 represents a monovalent organic group having carbon number of 1 to 200, having at least one hydroxyl group and optionally having a substituent other than the hydroxyl group; and M.sup.+ represents a counter cation.

A sulfonic acid derivative, wherein the sulfonic acid derivative is represented by the following general formula (1):

R.sup.1COOCH.sub.2CH.sub.2CFHCF.sub.2SO.sub.3.sup.−M.sup.+  (1)

where: R.sup.1 represents a monovalent organic group having carbon number of 1 to 200, having at least one hydroxyl group and optionally having a substituent other than the hydroxyl group; and M.sup.+ represents a counter cation.

A radiation-sensitive resin composition includes: a polymer, solubility of which in a developer solution is capable of being altered by an action of an acid; a radiation-sensitive acid generator; and a compound represented by formula (1). Ar.sup.1 represents a group obtained by removing (a+b+2) hydrogen atoms from an aromatic hydrocarbon ring having 6 to 30 ring atoms; R.sup.1 represents a halogen atom or a monovalent organic group having 1 to 20 carbon atoms; L.sup.1 represents a divalent linking group; R.sup.2 represents a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms; a is an integer of 0 to 10, b is an integer of 1 to 10, wherein a sum of a and b is no greater than 10; and X.sup.+ represents a monovalent radiation-sensitive onium cation.

##STR00001##

A radiation-sensitive resin composition includes: a polymer, solubility of which in a developer solution is capable of being altered by an action of an acid; a radiation-sensitive acid generator; and a compound represented by formula (1). Ar.sup.1 represents a group obtained by removing (a+b+2) hydrogen atoms from an aromatic hydrocarbon ring having 6 to 30 ring atoms; R.sup.1 represents a halogen atom or a monovalent organic group having 1 to 20 carbon atoms; L.sup.1 represents a divalent linking group; R.sup.2 represents a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms; a is an integer of 0 to 10, b is an integer of 1 to 10, wherein a sum of a and b is no greater than 10; and X.sup.+ represents a monovalent radiation-sensitive onium cation.

##STR00001##

A resist composition is provided comprising a base polymer and a quencher comprising a salt compound consisting of a cyclic ammonium cation and a 1,1,1,3,3,3-hexafluoro-2-propoxide anion having a trifluoromethyl, hydrocarbylcarbonyl or hydrocarbyloxycarbonyl group bonded thereto. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.

A resist composition is provided comprising a base polymer and a quencher comprising a salt compound consisting of a cyclic ammonium cation and a 1,1,1,3,3,3-hexafluoro-2-propoxide anion having a trifluoromethyl, hydrocarbylcarbonyl or hydrocarbyloxycarbonyl group bonded thereto. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.

Provided are a salt capable of producing a resist pattern with satisfactory CD uniformity (CDU), an acid generator, and a resist composition comprising the same. Disclosed are a salt represented by formula (I), an acid generator, and a resist composition comprising the same:

##STR00001##

wherein R.sup.4, R.sup.5, R.sup.7 and R.sup.8 each represent a halogen atom, a haloalkyl group or a hydrocarbon group; A.sup.1 and A.sup.2 each represent a hydrocarbon group, the hydrocarbon group may have a substituent, and —CH.sub.2— included in the hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO.sub.2—; ml represents an integer of 1 to 5, m2, m4, m5 and m8 represent an integer of 0 to 5, m7 represents an integer of 0 to 4, 1≤m1+m7≤5, 0≤m2+m8≤5; and AI.sup.− represents an organic anion.

Provided are a salt capable of producing a resist pattern with satisfactory CD uniformity (CDU), an acid generator, and a resist composition comprising the same. Disclosed are a salt represented by formula (I), an acid generator, and a resist composition comprising the same:

##STR00001##

wherein R.sup.4, R.sup.5, R.sup.7 and R.sup.8 each represent a halogen atom, a haloalkyl group or a hydrocarbon group; A.sup.1 and A.sup.2 each represent a hydrocarbon group, the hydrocarbon group may have a substituent, and —CH.sub.2— included in the hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO.sub.2—; ml represents an integer of 1 to 5, m2, m4, m5 and m8 represent an integer of 0 to 5, m7 represents an integer of 0 to 4, 1≤m1+m7≤5, 0≤m2+m8≤5; and AI.sup.− represents an organic anion.