Comparison of PEC Approaches for SCALPEL

SCALPEL is a projection electron lithography technology with resolution limited by aberrations and electron-electron interactions, not diffraction. The main CD control issue is adequate dose latitude, for image blur approaching the feature size in a high throughput scenario. This includes the effect of the unwanted electron back- scatter (EBS) proximity dose. Due to operation at 100KeV, the back-scatter range is large (~ 25 microns) and resulting CD changes depend only on the density surroundings of a critical feature. We compare mask pattern data biasing (adjustment of binary mask object sizes) with our proposed SHOST scheme; both available as methods of proximity effect correction (PEC). We demonstrate data bias for a gate-level test pattern with realistic features and density, using a very simple model. These CD control results are confirmed with CAPROX(TM), a complete device- driven PEC calculation tool from Sigma-C.