Patent ID: 7527910

Claim:
A salt of the formula (I): wherein X represents alkylene group or substituted alkylene group in which a —CH 2 — except for the one connected to the adjacent —COO— is substituted with —S— or —O—; Y represents hydrocarbon ring group containing at least one aromatic ring and having 5 to 30 carbon atoms in which one or more of —CH 2 — on the hydrocarbon ring is optionally substituted with —O— or —CO— and in which one or more of hydrogen atom on the hydrocarbon ring is optionally substituted with alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, 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 fluorine atom or perfluoroalkyl group having 1 to 6 carbon atoms; A + represents organic counter ion; and n shows 0 or 1.