Salt and photoresist composition containing the same

A salt comprising an anion represented by formula (aa2):

• wherein Xa and Xb independently each represent an oxygen atom or a sulfur atom,
• a ring W represents a C3-C18 heterocycle which has a carbonate ester structure and which can have a substituent,
• a ring W1 represents a C3-C18 non-aromatic hydrocarbon ring which can have a substitute and in which a methylene group can be replaced by —O—, —S—, —CO— or —SO2—,
• L1 represents a C1-C24 divalent saturated hydrocarbon group in which a hydrogen atom can be replaced by a fluorine atom or a hydroxyl group and in which a methylene group can be replaced by —O— or —CO—, and
• Q1 and Q2 independently each represent a fluorine atom or a C1-C6 perfluoroalkyl group.