One-component chemically amplified resist composed of polymeric sulfonium salt PAGs for high resolution patterning

Abstract Photoacid generator (PAG) bound polymers have been developed to form chemically amplified resists (CARs) due to their improved lithographic performance. With poly(sodium p-styrenesulfonate-co-4-hydroxystyrene-co-alkyl methacrylate) prepared as a precursor, a new type of PAG bound polymers are synthesized with sulfonium salts units bonded onto the copolymers and partly protection of phenolic hydroxy groups with t-BOC groups. The PAG bound polymers exihibit good solubilities in common resist solvents, high thermal stability and moderate absorbance at 248 nm. Upon irradiation, the sulfonium salt units undergo photolysis effectively to generate a small amount of polymeric sulfonic acids. By incorporating the sulfonium salt PAGs and the acidolytic t-BOC protect groups into the same polymer chains, we can prepare one-component positive-tone chemically amplified resists (CARs) with this new kind of PAG bound polymer. The photolithography of the resists are evaluated with KrF laser stepper and show outstanding performance in resolution and photosensitivity.