Aqueous base development and acid diffusion length optimization in negative epoxy resist for electron beam lithography

A new aqueous base developable, chemically amplified negative resist based on epoxy chemistry is evaluated for high-resolution, high-speed e-beam lith ography. This resist is formulated using partially hydrogenated poly(hydrox y styrene) and epoxy novolac polymers. Degree of hydrogenation controls the aqueous base solubility and microphase separation phenomena. Reduction of edge roughness compared to the pure epoxy systems is observed whereas the a bsence of swelling phenomena allows lithography up to 100 nm regime and a s ensitivity of 4-8 muC/cm(2) at 50 keV. The diffusion coefficient has been e valuated both from high-resolution line and dot exposures and it is found t o be 5X10(-14) cm(2)/s for the optimal thermal processing conditions select ed. (C) 2000 American Vacuum Society. [S0734-211X(00)15806-8].