Evaluation and application of a very high performance chemically amplified resist for electron‐beam lithography

This article reports on sub‐0.25 μm electron‐beam lithography using a new positive‐tone chemically amplified resist system called KRS. Unlike conventional chemically amplified resist systems, KRS is immune to N‐methylpyrolidone contamination and does not require a postexposure bake step. The resist is aqueous developable and shows a contrast figure of about 10 and a sensitivity of about 12 μC/cm2 at 50 kV. A 0.15 μm feature size with a shaped‐beam system in 0.8 μm thick resist on silicon with −0.05 μm print bias was achieved. Sub‐100 nm features are resolved in 0.3 μm thick KRS using a high‐resolution Gaussian‐beam system. The resist was found to be extremely suitable for patterning densely packed, high resolution, and high aspect ratio structures. As examples, the application of this resist for fabricating high resolution x‐ray masks and very high performance 0.1 μm gate‐length n‐metal–oxide–semiconductor field effect transistors are reported.