Influence of Acid Diffusion on the Lithographic Performance of Chemically Amplified Resists

The distribution of chemical amplification reactions incidental to catalytic acid diffusion is calculated to clarify its influence on the lithographic performance of chemically amplified resists. The distribution of the chemical amplification reaction is less extensive than that of catalytic acid. There exists an optimum diffusion length for maximizing sensitivity without sacrificing resolution. Acid diffusion coefficients in the chemically amplified resist EXP are 15 nm 2 /s at 55°C and 50 nm 2 /s at 65°C. A trade-off between sensitivity and resolution is observed in the EXP, which is attributed to acid diffusion. The relation between the variables is formulated by ( Resolution )\propt( Sensitivity ) -1/2 on the basis of a simple model, and guidelines are proposed for the material design of high-performance chemically amplified resists.