AlSixNy as an embedded layer for attenuated phase-shifting mask in 193 nm and the utilization of a chemically amplified negative resist NEB-22 for maskmaking

Abstract

AlSixNy (x similar to 0.31, y similar to 0.45) thin film as a new embedded material for AttPSM in 193 nm lithography was presented. With the good controlling of plasma sputtering of Al (100 similar to 130 W) and Si (20 similar to 50 W) under Ar (75 seem), and nitrogen (2.5 similar to 5 seem), AlSixNy has enough deposition latitude to meet the requirements as an embedded layer. For required phase shift 180 degree, the calculated thickness d(180) of AlSixNy films is in the range of 87 similar to 100 nm. The T% in 365 and 488 nm for optical inspection and alignment is below 40%. Its sheet resistance R-s, is less than 0.8 k Omega/square. Helicon wave plasma etcher and Taguchi design of experiment have been applied to the study of the etching selectivity of AlSixNy over substrate fused silica and negative resist NEB-22. Under chamber pressure 3 mtorr, BCl3 45 sccm, Cl-2 7 seem, plasma source power 1400 W and substrate bias RF power 30 W for the selectivity of AlSixNy over NEB-22 was found to be 4.8:1. The selectivity of AlSixNy over fused silica was 12.3:1 under chamber pressure 9 mtorr, BCl3 13 seem, Cl-2 45 seem, O-2 8 seem, plasma source power 1400 W and substrate bias RF power 30 W. A 0.3 mu m line/space etched pattern using AlSixNy as embedded layer was successfully fabricated.