Methacrylic silicon-containing tercopolymers for chemically amplified resists

Tercopolymers of methyl methacrylate with methacrylic acid and dimethylphenyl (methyldiphenyl)silyl methacrylates are synthesized and investigated as components of chemically amplified resistive formulations with sulfonium and iodonium salts as photoacid generators for UV lithography in the 254-nm range. The surface behavior and the kinetics of dissolution of resistive films in an aqueous solution of tetraethylammonium hydroxide in relation to the concentration of onium salts and the temperatures of postapply and postexposure bakes are studied. The introduction of sulfonium salt into the resistive formulation brings about an increase in the solubility of unexposed films, thereby erasing the difference in dissolution rates of exposed and unexposed areas of a resist and preventing image formation. The iodonium salt plays the role of an inhibitor for dissolution of unexposed films of both copolymers, which makes it possible to obtain a high-contrast positive image in resists.