Optimization of Ion Beam Etch Sidewall Angle in Mo and Cr Films
Abstract– We studied the effect of performing a two-angle Ion Beam etch process in shaping the sidewall profiles of patterned Mo and Cr films. Cross-sectional SEM is used to study both the sidewall angle and the effects of redeposition on the sidewall shape. By etching first at 45° and then 5°, favorable sidewall profiles for further processing and conformal coverage are produced. We find that a total high-angle etch time of 30-40% produces sidewall angles near 80° with minimal trenching in both single edges and in 70 nm width, 200 nm period, 45 nm thick line features.