Silicon-oxynitride films prepared for 157-nm attenuated phase-shifting masks

Abstract

Suitable silicon-oxynitride films for constructing the attenuated phase shifting masks (APSM's) to be operated in the 157 am excimer laser regime are obtained by varying the gas flow ratios in a RF sputtering process. Characteristics of the films such as optical constants, material compositions, etching selectivity, surface profiles, and adhesion strength are experimentally analyzed. These results indicate that the silicon-oxynitride films thus fabricated can meet the requirements for building such APSM's working in the wavelength of 157 am.