Effect of initial molecular weight distribution on pattern formation of main-chain-scission-type resists

Abstract

Recently, main-chain-scission-type resists have attracted considerable interest because of their highly resolving properties. In this study, the effect of initial molecular weight distribution on the pattern formation of main-chain-scission-type resists was investigated. The main-chain-scission-type resists with different molecular weight distributions were prepared by blending ZEP520A (M w, 56,000; M w/M n: 2.2) and ZEP7000 (M w, 412 000; M w/M n, 2.6) of Zeon. Independently of their initial molecular weight distribution, the molecular weight distributions of the resists become similar through the random main-chain scission. However, the initial molecular weight distribution affected the formation of boundaries between lines and spaces. When their weight ratio was 1:1, the bridges formed by pattern collapse or transient swelling were clearly observed at an irradiation dose lower than those in the case of the other weight ratios.