Acid photogeneration from sulfonium salts in solid polymer matrices

Abstract

Much photoresist research in recent years has focused on the area of acid-catalyzed resist systems. These resists are unique in that the primary photochemistry results in the formation of an acid and then in a subsequent step the acid is employed to catalys is a bulk chemical change. The overall resist lithographic performance is thus not limited to only photochemical change and as a result extremely high resist sensitivities have been demonstrated by using acid catalysis. There are a number of photosensitizers which produce Bronsted acid on irradiation. Despite the impressive number of resists schemes which employ triphenylsulfonium salts, very little information is available on the efficiency of acid generation in resist films. The quantum yields for acid production in solution are quite high. The purpose of the present study was to determine the quantum yields in a solid polymer matrix. A merocyanine dye technique was applied for acid measurement.