Analysis of a SCALPEL™ multi-pass writing strategy

In SCALPEL(TM). the microcircuit pattern information is written on the wafer in a series of stripes, typically 2.75 mm wide with 0.24 mm pitch. To distribute the heat in the wafer as evenly as possible, each stripe may be written with multiple passes of the sub-field illumination along each stripe, and a blending scheme will be used to improve the dose uniformity and reduce CD errors near the boundaries at the ends and sides of each stripe. Our software has been extended to simulate the performance of SCALPEL(TM) including multi-pass writing strategies and blending regions. The method is described and illustrative results are presented. The results show that there is no significant loss of performance due to the multi-pass and blending schemes.