Patent ID: 7579497

Claim:
A salt of the formula (I): wherein ring Y represents monocyclic or polycyclic hydrocarbon group having 3 to 30 carbon atoms, in which one —CH 2 — group is substituted with —COO— group, and at least one hydrogen atom in the monocyclic or polycyclic hydrocarbon group may optionally be substituted with alkyl group having 1 to 6 carbon atom, alkoxy group having 1 to 6 carbon atom, perfluoroalkyl group having 1 to 4 carbon atoms, hydroxyalkyl group having 1 to 6 carbon atoms, hydroxyl group or cyano group; Q 1 and Q 2 each independently represent a fluorine atom; n is an integer of 0 to 12; and A + is a cation of the formula (IIa) wherein P 1 , P 2 and P 3 each independently represent hydrogen atom, hydroxyl group, alkyl group having 1 to 12 carbon atoms or alkoxy group having 1 to 12 carbon atoms.