Surface property control for 193 nm immersion resist by addition of Si compound

Abstract

In ArF immersion lithography, the presence of immersion liquid between the resist surface and the lens causes problems, such as the leaching of the photoacid generator into the liquid and the presence of residual liquid on the resist surface, which can result in watermarks and other defects. One method to address such issues is adding an F-based compound with low dry-etch resistance to the resist. In the present study, we developed a novel resist for ArF immersion exposure that replaces the F compound with an Si (dimethylpolysiloxane)-based additive to enhance dry-etch resistance. We experimentally evaluated contact angles with respect to water and developer solution, depth concentration of the additives (segregation), agent dissolution (leaching), dry-etch resistance, and spectral transmittance of the comparative resists. Simulation studies were performed to evaluate pattern profiles. The developed resist with the Si-based additive showed improved properties compared with that with the F-based additive.