Thermal effects study of chemically amplified resist

Abstract

For the sub-100-nm pattern generation, thermal treatment is one of the new process extension techniques with current day lithography equipment and chemically-amplified resist. The key element to introduce these new techniques is in the understanding of mechanistic behaviors that drive photo resist image rendering. Thermal processes, such as soft bake, post exposure bake, and thermal reflow process, are same thermal processes, but produce different chemical and physical behaviors in the chemically-amplified resist. In this paper, those thermal processes are described and modeled for the property change of a positive type 193 nm chemically amplified resist. Those simulated results agree well with experimental results. Those thermal effects move the boundaries of resist bulk images to a center point and make these boundaries dense. Due to pattern types, the thermal reflow process technology and the overbake and underbake technologies of soft bake and post exposure bake can be used for the 45 nm critical dimension. Combining the benefits of thermal processes becomes possible to produced the below 45 nm critical dimension.