The trouble starts with using electrons - Putting charging effect correction models to the test

摘要

Improvement of pattern placement accuracy is essential to solve upcoming challenges in mask making. Placement errors are driven by multiple effects with electron mediated resist surface charging being a major error source. Modeling this systematic effect thus allows the determination of the placement errors before plate processing. This opens the door to an effective charging compensation. In this paper we study the simulated benefit of two distinct charging compensation models in the context of full-scale mask production layouts. The potential pattern placement improvements are evaluated using actual placement results obtained without charging effect corrections. An in depth comparison of the two models is presented, demonstrating the differences in placement error prediction between using a static or a dynamic charging model. We find that substantial improvements can be achieved using the dynamic charging model. Productive implementation of this functionality is the natural next step.