TiSixNy and TiSixOyNz as embedded materials for attenuated phase-shifting mask in 193 nm

Abstract

TiSixNy and TiSixOyNz were presented as new embedded materials for APSM in 193 nm lithography. TiSixNy films were formed by plasma sputtering of Ti (180 similar to 230 W) and Si (60 similar to 80 W) under Ar (50 seem) and nitrogen (4 similar to 6 seem). For required phase shift degree theta = 180 degrees, the calculated thickness d(180) of TiSixNy film is 82 similar to 93 nm. TiSixOyNz films were formed by plasma sputtering of Ti (200 similar to 240 W) and Si (60 similar to 80 W) under Ar (50 sccm), nitrogen (4 similar to 6 seem) and oxygen (0.2 similar to 0.7 seem). The d(180) of TiSixOyNz film is 92 similar to 105 nm. With the thickness d(180), the transmittance at visible wavelength (488, 632.8 nm) for optical alignment is 35 similar to 50% for TiSixNy and TiSixOyNz. Under BCl3:Cl-2=14:70 seem; chamber pressure 4 mtorr and RF power 1900 W, the dry etching selectivity of TiSixNy over DQN positive resist and fused silica, were found to be 2:1 and 4.8.1, respectively. A TiSixNy embedded layer with 0.6 mu m lines/space was successfully patterned.