Studies of nitride- and oxide-based materials as absorptive shifters for embedded attenuated phase-shifting mask in 193 nm

Abstract

Five materials which are PdSixOy CrAlxOy, SiNx, TiSixNy and TiSixOyNz as absorptive shifters for attenuated phase-shifting mask in 193 nm wavelength lithography are presented. PdSixOy films were deposited by dual e-gun evaporation. CrAlxOy, TiSixNy and TiSixOyNz films were formed by plasma sputtering and SiNx films were formed with LPCVD. All of these materials are shown to be capable of achieving 4%similar to 15% transmittance in 193 nm with thickness that produce a 180 degrees phase shift. Under BCl3:Cl-2=14:70 seem; chamber pressure 4 mtorr and RF power 1900W, the dry etching selectivity of TiSixNy over DQN positive resist and fused silica, were found to be 2:1 and 4.8:1, respectively. An embedded layer TiSixNy with 0.5 mu m line/space was successfully patterned.