Pattern Processing Results and Characteristics for SCALPEL(TM) Masks

SCALPEL(TM) (SCattering with Angular Limitation in Projection Electron Beam Lithography) masks consisting of a 150 nm thick SiN sub x, membrane layer and 25-27.5 nm and 5-6 nm thick tungsten and chromium scatterer bi-layer have been fabricated and used to investigate pattern transfer processes for the mask scatterer layer. Wet and dry (plasma) processes have been developed and investigated in terms CD control, uniformity, linearity and line edge roughness. Introduction of a baking step after resist development was found to improve the resist and scatterer layer pattern edge quality. Wet pattern transfer processes are shown to meet CD specifications down to 0.40 micron and the dry process provided meeting CD specifications down to 0.32 micron. CD uniformity for the dry process was measured to be 15 nm 3 sigma.