Space-charge results from the SCALPEL proof-of-concept system

Charged particle lithography systems face a unique challenge because throughput and resolution are linked though the dependence of beam blur on beam current. Understanding the functional form of this dependence is vital, both for understanding the throughput limits of such systems, and also for the purposes of optimizing system designs. We have developed a simple model describing the effects of image blur on printed resist feature size. The uncertainty in resist feature measurement enables us to determine the overall image blur to an accuracy of approximate to 5 nm. We have also begun to develop an aerial image monitoring scheme that can, in principle, measure the image blur to an accuracy of less than or equal to 1 nm. While the resist based measurement scheme is useful for determining large space-charge blurs, and for optimizing the resist itself, the aerial image monitoring approach has sufficient accuracy to allow us to determine the functional dependence of beam blur on current.