Method and apparatus for enhancing resist sensitivity and resolution by application of an alternating electric field during post-exposure bake

摘要

A method for enhancing resist sensitivity and resolution based on influencing the effects of photoacid drift and diffusion by an externally applied electric field that may optionally include a direct current offset bias is disclosed. An electric field applied to the resist film during post exposure bake (PEB) enhances photoacid drift in the direction of the applied electric field, reduces bake time, and results in less undesired diffusion. Electric-field enhanced PEB can reduce PEB time by about 30%, and at the same time, improve the sharpness of 2D corners and increase the verticality of resist sidewalls. Electric-field-enhanced PEB also significantly improves the tolerance of over-exposure and provides better critical dimension control. It is estimated that the lateral acid diffusion length is reduced by about 50%. An apparatus for carrying out the aforementioned method is also provided.