Silylation of (photo)resist materials using polyfunctional organosilicon compounds

Abstract

The silylation of novolak based photoresists using polyfunctional organosilicon compounds was studied. The most effective silylating agent of the 12 compounds studied, was bis(dimethylamino)dimethylsilane. It was found that the rate of silylation indicated a diffusion process which was limited to the chemical reactivity of the silylating agent with both the base resin and the photoactive compound. Notably it was determined that the higher the reactivity of the organosilicon compound, the smaller was the extent of silylation due to the formation of a diffusion barrier as a result of crosslinking. The oxygen plasma etch rates of the silylated resist film were found to be effected by a pre-silylation UV exposure step. The unexpected films showed an irregular etch rates, whereas exposed and then silylated films showed a uniform etch rate of about 40 A/min.