Relationship between blurring factors and interfacial effects in chemically amplified resist processes in photomask fabrication

Abstract

Chemically amplified resists are an indispensable technology for photomask fabrication. The formation of latent images near interfaces in resist films is strongly affected by low-energy electron dynamics at the interfaces. On the other hand, the latent images are blurred by low-energy electron migration and acid diffusion in latent image formation. In this study, the relationship between blurring factors and interfacial effects was investigated by simulating the latent image formation on the basis of the sensitization and reaction mechanisms of chemically amplified electron beam resists. For low-energy electron dynamics, the interfacial effects on the protected unit distribution was reduced and the chemical gradient slightly increased with decreasing thermalization distance. For acid diffusion, the decrease in exposure pattern width significantly reduced the interfacial effects on the protected unit distribution in the depth direction because the acid diffusion length can be increased without sacrificing resolution.