A salt represented by formula (I): ##STR00001##
wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom, a hydroxy group or a C.sub.1 to C.sub.12 hydrocarbon group in which a methylene group may be replaced by a —O— or —CO—; m and n independently represent 1 or 2; Ar represents an optionally substituted phenyl group; Q.sup.1 and Q.sup.2 independently represent a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, A.sup.1 represents a single bond, a C.sub.1 to C.sub.24 alkanediyl group or the like, and Y represents an optionally substituted C.sub.1 to C.sub.18 alkyl group or monovalent C.sub.3 to C.sub.18 alicyclic hydrocarbon group, and a methylene group therein may be replaced by a —O—, O— or —SO.sub.2—, provided that the alkyl group or the alicyclic hydrocarbon group has at least one substituent, or at least one methylene group contained therein is replaced by a —O—, —CO— or —SO.sub.2—.

A salt represented by formula (I): ##STR00001##
wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom, a hydroxy group or a C.sub.1 to C.sub.12 hydrocarbon group in which a methylene group may be replaced by a —O— or —CO—; m and n independently represent 1 or 2; Ar represents an optionally substituted phenyl group; Q.sup.1 and Q.sup.2 independently represent a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, A.sup.1 represents a single bond, a C.sub.1 to C.sub.24 alkanediyl group or the like, and Y represents an optionally substituted C.sub.1 to C.sub.18 alkyl group or monovalent C.sub.3 to C.sub.18 alicyclic hydrocarbon group, and a methylene group therein may be replaced by a —O—, O— or —SO.sub.2—, provided that the alkyl group or the alicyclic hydrocarbon group has at least one substituent, or at least one methylene group contained therein is replaced by a —O—, —CO— or —SO.sub.2—.

A compound represented by formula (I): ##STR00001##
wherein R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 represents a C1-C12 hydrocarbon group; X.sup.a and X.sup.b each independently represent an oxygen atom or a sulfur atom; X.sup.11 represents a C1-C12 divalent saturated hydrocarbon group where a hydrogen atom can be replaced by a fluorine atom; and A.sup.1 represents a C1-C12 divalent saturated hydrocarbon group or *-A.sup.2-X.sup.1-(A.sup.3-X.sup.2).sub.a-A.sup.4-, where * represents a binding site to an oxygen atom, A.sup.2, A.sup.3 and A.sup.4 each independently represent a C1-C12 divalent hydrocarbon group, X.sup.1 and X.sup.2 each independently represent O, COO, OCO or OCOO, and a represents 0 or 1.

A compound represented by formula (I): ##STR00001##
wherein R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 represents a C1-C12 hydrocarbon group; X.sup.a and X.sup.b each independently represent an oxygen atom or a sulfur atom; X.sup.11 represents a C1-C12 divalent saturated hydrocarbon group where a hydrogen atom can be replaced by a fluorine atom; and A.sup.1 represents a C1-C12 divalent saturated hydrocarbon group or *-A.sup.2-X.sup.1-(A.sup.3-X.sup.2).sub.a-A.sup.4-, where * represents a binding site to an oxygen atom, A.sup.2, A.sup.3 and A.sup.4 each independently represent a C1-C12 divalent hydrocarbon group, X.sup.1 and X.sup.2 each independently represent O, COO, OCO or OCOO, and a represents 0 or 1.