Sulfonate salts have the formula: CF.sub.3--CH(OCOR)--CF.sub.2SO.sub.3.sup.-M.sup.+ wherein R is C.sub.1-C.sub.20 alkyl or C.sub.6-C.sub.14 aryl, and M.sup.+ is a lithium, sodium, potassium, ammonium or tetramethylammonium ion. Onium salts, oximesulfonates and sulfonyloxyimides and other compounds derived from these sulfonate salts are effective photoacid generators in chemically amplified resist compositions.