Resist processes for hybrid (electron-beam deep ultraviolet) lithography

This article describes the different mix and match writing strategies using both an optical deep ultraviolet (DUV) stepper (ASML/90) and an electron-b eam (e-beam) system (LEICA VB6HR) with both positive and negative tone chem ically amplified resists. These resists, mainly developed for DUV applicati ons, have shown very good performance under e-beam exposure. Negative tone resists such as the Shipley XP90166 and UVN2, and positive tone resists suc h as the Shipley UVIII and UV5 have been optimized in terms of soft bake te mperatures, postexposure bake temperatures, and development process. Resolu tions in the range of 40-50 nm have been obtained using a 50 keV accelerati ng voltage. Delay time effect has been quantified and different behaviors u nder vacuum and in air have been pointed out. (C) 1998 American Vacuum Soci ety. [S0734-211X(98)15906-1].