Resist Sensitivity Enhancement by Radiation-Induced Modification

摘要

Exposure of poly methy methacrylate. PMMA to electrons, protons, xrays and ultraviolet radiation creates free radicals which combine with acrylic acid in a chain reaction to form graft and/or block copolymers with solubilities different from PMMA. Appropriate solvents develop negative images generated at doses on the order of 1,000 times less than those needed to form positive images in PMMA. At doses exceeding optimum values growth of the image occurs vertically and laterally. High fidelity replication can be accomplished by controlling dose and by using more aggressive solvents. Enhanced dry etch resistance can be conferred on the acrylic acid-modified PMMA by permitting it to imbibe calcium ion. Keywords: Polymethyl methacrylates. (MJM)