Post-Exposure Bake Temperature Considerations for High Activation Energy Resist Systems.

Polymers based on tertiary-butyl acrylate were synthesized with different compositions and glass transition temperature (Tg) values. These polymers are formulated identically and exposed under identical optical conditions. Lithographically, these polymers responded differently to different post exposure bake temperature (TPEB) conditions. In general, resist contrast, photosensitivity and PED-sensitivity improved at TPEB above polymer-Tg. The resist resolving power improved as TPEB approaches polymer-Tg. However, loss of resolution is observed at TPEB above polymer-Tg. Also, high Tg polymers show greater PEB sensitivity than the corresponding low Tg-polymers.