Protected unit distribution near interfaces of chemically amplified resists used for extreme ultraviolet lithography

In the nanofabrication, the interfacial effects are a serious issue. The effects of resist interfaces on the dynamics of low-energy (near thermal energy) electrons are among them for extreme ultraviolet lithography. In this study, the interfacial effects on the protected unit distribution (latent image) of chemically amplified resists were investigated using a simulation on the basis of their sensitization and reaction mechanisms. The formation of the latent images of line-and-space patterns with 12–32 nm pitch was calculated, assuming the chemically amplified resists consisting of an acid generator, a photodecomposable quencher, and partially protected acidic polymer. The aspect ratio was 2. The boundary conditions at the resist interfaces had a significant impact on the latent images near the resist interfaces even for the line-and-space patterns with 32 nm pitch. With a decrease of the pitch, the effects of boundary conditions became affecting the latent image even at the center (half-depth).