Implementation of a chemo-epitaxy flow for directed self-assembly on 300-mm wafer processing equipment

The implementation of our previously reported chemo-epitaxy method for directed self-assembly (DSA) of block copolymers (BCPs) on 300-mm wafers is described in detail. Some challenges to be addressed include edge bead removal control of the layers forming the exposure stack and uniformity of the deposited films across the wafer. With the fine tuning of the process conditions, this flow provides chemically nanopatterned substrates with well-defined geometry and chemistry. After a film of BCP is annealed on the chemical patterns, high degrees of perfection are achieved. A BCP with natural periodicity of 25 nm was assembled on100-nm pitch prepatterns, obtaining 4X feature multiplication. Top-down scanning electron microscope images show a wide process window with depth of focus >200 nm and exposure latitude >40% for lines and spaces of 12.5-nm half-pitch. We provide a platform for future study of the origin of DSA generated defects and their relationship to process conditions and materials that are amenable to use by the semiconductor industry.