Pattern processing results and characteristics for SCALPEL masks

SCALPEL (SCattering with Angular Limitation in Projection Electron Beam Lit hography) masks consisting of a 150 nm thick SiNx membrane layer and 25-27. 5 nm and 5-6 nm thick tungsten and chromium scatterer bi-layer have been fa bricated and used to investigate pattern transfer processes for the mask sc atterer layer. Wet and dry (plasma) processes have been developed and inves tigated in terms of CD control, uniformity, linearity and line edge roughne ss. Introduction of a baking step after resist development was found to imp rove the resist and scatterer layer pattern edge quality. Wet pattern trans fer processes are shown to meet CD specifications down to 0.40 mu m and the dry process provided meeting CD specifications down to 0.32 mu m CD unifor mity for the dry process was measured to be 15 nm 30.