Challenges of implementing contour modeling in 32nm technology

Optical Proximity Correction (OPC) Model Calibration has required an increasing number of measurements as the critical dimension tolerances have gotten smaller. Measurement of two dimensional features have been increasing at a faster rate than features with one dimensional character as the technologies require better accuracy in the OPC models for line-end pull-back and corner rounding. New techniques are becoming available from metrology tool manufacturers to produce GDSII contours of shapes from wafers and modeling software has been improved to use these contours. The challenges of implementing contour generation from the SEM tools will be discussed including calibration methods, physical dimensions, algorithm derivations, and contour registration, resolution, scan direction, and parameter space coverage.