Dissolution characteristics of chemically amplified 193 nm resists

Abstract

The dissolution kinetics of two types of chemically amplified positive 193 nm resists were investigated; a ter-polymer resist consisting of poly(tricyclodecylacrylate-co-tetrahydrodpyranyl-methacrylate-co-methacrylic acid) and triphenylsulfonium triflate as a photoacid generator, and a copolymer resist consisting of poly(carboxytetracyclododecylmethacrylate-co-tetrahydro-pyranyloxy-carbonyl-tetracyclododecylmethacrylate) and triphenylsulfonium triflate as a photoacid generator. The dissolution rate contrast was higher and the slope of dissolution rate curve was steeper for the ter-polymer resist than those for the copolymer resist. However, the Arrhenius plots of the dissolution rates were straight lines for both resists irrespective of the exposure doses. This indicates that only one mechanism determines the dissolution of both resists, and it is believed that the dominant rate-determining step in both resists is the tetramethylammoniumhydroxide penetration into the resist films. The resolution capability of the ter-polymer resist was very high, 0.14 μm lines and spaces pattern. The resolution capability of the copolymer resist was moderate, 0.16 μm lines and spaces in spite of its lower dissolution contrast and smaller slope value. In addition, the dry-etch resistance of both resists was close to that of a conventional polyhydroxystyrene base KrF resist. These results indicate that both the ter-polymer and the copolymer resists are candidates for practical use.