Formulation robustness of a chemically amplified ESCAP-type resist based on hydroxystyrene/t-butyl acrylate copolymer

This paper describes the formulation robustness of an 'ESCAP' type resist based on hydroxystyrene/t-butyl acrylate copolymer. The resist formation matrix consists of the polymer, a photo acid generator (PAG) and a base. The performance of the resist design was tested lithographically over 900 angstrom DUV-30 BARC as a function of variations in the PAG concentration and the base ratio to the PAG. The post exposure bake (PEB) temperature was also investigated as a third process variable in addition to the first two formation variables. The analysis of the results shows high performance tolerance to the formation variables. The resolution, focus latitude and exposure margin exhibited high tolerance to changes in the PEB temperature, PAG or base ratios.