The effect of diffusion, reaction order, and developer selectivity on the performance of positive DUV resists

Abstract

Two different positive acid catalyzed DUV resists were investigated and the differences in the reaction order, developer selectivity, and magnitude of acid diffusion were determined. The threshold acid theory of image formation is used in conjunction with a reaction-diffusion model to determine the reaction order of the acid catalyzed deprotection reaction and the effect of acid diffusion in positive DUV resists. The acid diffusion coefficient for these positive DUV resists was also measured. Finally, the developer selectivity of the different resists was determined and the effect of developer selectivity on resist performance was presented. It was also shown that this model does apply to positive acid catalyzed resists and thus can have general utility in describing acid catalyzed resist performance.