Sensitive polysilane resists for bilayer lithography

Abstract

Previously, we described the use of sensitizing additives in polysilane photoresists for wet developing processes. The systems show a 10 fold increase in photospeed (i.e. a resist sensitivity of < 20mJ/cm2 at 248 nm) using non-optimized formulations. In the following discussion, we would like to describe the extension of this technique to the particular 'all dry' developing system described above and also to discuss some of the chemistry which we believe to be common to both the wet and dry developing processes. We have described a technique to dramatically increase the sensitivity of polysilane resists used in 248 nm wet developed and 193 nm HBr dry etched bilayer schemes. A common feature of both systems is the use of certain small molecule additives. Based on preliminary experiments, it would appear that the enhanced photodegradation observed after electron transfer may be more complicated than the simple fragmentation of the polysilane radical cation.