| Several new families of chemically amplified photoresists were designed, synthesized and evaluated for microlithography. These materials were based on copolymers of the following but-2-enedioic acid derivatives: (i) maleic anhydride, maleic acid, fumaric acid; (ii) maleic or fumaric acid monoester; and (iii) fumaric acid di-t-butyl ester. Heating with photogenerated strong acid induced significant alteration of copolymer properties by acid-catalyzed reactions of, respectively: (i) dehydration, (ii) dehydroallcoxylation, and (iii) de-alkenation. Depending on the developing solvent, both negative-tone and positive-tone relief images were obtained with 1 micron resolution. The material alteration also allowed further patterned chemical modification ("functional development"), such as through sorption of various organic and inorganic species from contacting solutions or vapours into either exposed or unexposed resist areas. |
