POST-EXPOSURE-BAKE SIMULATION-MODEL WITH CONSTANT ACID LOSS OF CHEMICALLY AMPLIFIED RESIST

The post-exposure-bake (PEB) deprotective reaction was investigated as a function of the exposure energy and bake time with FT-IR spectrum m easurements of chemically amplified resist. It was found that the FEB deprotection model giving an acid loss rate that is proportional to it s concentration cannot describe the suppression of deprotection for re latively low exposure energies. This paper proposes a FEB reaction mod el that gives an acid loss whose rate remains constant irrespective of the concentration, which can describe the suppression accurately. In addition, a constant acid loss enhances contrast of the resist develop ment, which was observed experimentally over relatively long FEB times .