Sulfonium salt and chemically amplified positive resist composition

Abstract

Trifluoromethanesulfonic and p-toluenesulfonic acid bis- or tris(p-tert-butoxyphenyl)sulfonium salts are novel. They are prepared from bis(p-tert-butoxyphenyl)sulfoxide which is also novel. A chemically amplified positive resist composition which contains the sulfonium salt as a photo-acid generator is highly sensitive to deep-UV rays, electron beams and X-rays, can be developed with alkaline aqueous solution to form a pattern, and is thus suitable for use in a fine patterning technique.

Dependencies are inferred from the claim text.