Accurate device simulations through CD-SEM-based edge-contour extraction

A new methodology to predict changes in device performances due to systematic lithography and etch effects is described in this paper. Our methodology consists on Automatic Edge-Contour-Extraction (ECE) on Poly Over Active Layer, taking along the manufacturing variability. In general, the AMAT SEM (Scanning Electron Microscopy) ECE algorithm is based on CAD (GDS) to SEM pattern recognition, followed by CD based 2D edge extraction. Device modeling (using SPICE simulation) is used, to predict the nominal values as well as the device performances variability of the transistors drive current (Ion) and leakage current (Ioff). We used our method to compare a classical (simple rectangular) transistors and "U-Shape AA" transistors, both manufactured using Tower TS013LL (0.13um Low-Leakage) Platform. It was found, as predicted, that U-shape transistors have larger W distribution. However, "U-shape" also showed much tighter L distribution and the overall Ion spread is lower comparing to classical transistors. Also, U-Shape transistors found to have lower Lstdev (gate length distribution of each individual transistor). We also used the ECE methodology, to compare transistors of single side dog-bone to double-side dog-bone. Based on our work, we can predict that single-side dog-bone transistors, will have higher and larger Ioff distributions, and the overall Ioff speared along the wafer, will go up to a factor of x2.5.