Statistical analysis of poly line printability affected by sPSM manufacturing errors

LSI Logic's OPC package, Molotof, integrated into several RET flows has been successfully applied for strong phase shift mask simulation and optimization. Molotof simulator was used to predict sPSM imaging performance in response to statistical errors of alternating phase shift reticle manufacturing. Mask manufacturing errors were reproduced by generating a virtual gds mask with random values of sPSM control parameters such as phase depth, phase width and phase intensity. By measuring critical dimensions and image placement errors of a simulated aerial image for each random event, the image printability performance was calculated. The approach allows for quantitative evaluation and optimization of a strong PSM manufacturing specification by analyzing the distributions of critical dimensions and image placement errors. 2D-model, metrology and simulation flow for performing statistical analysis are discussed. Sensitivity to a single parameter variation and full statistical analysis of the 90nm poly line imaging performance affected by manufacturing errors is presented. The optimum range of phase depth, phase width and phase intensity, yielded 100% of critical dimensions and image placement errors, complying with 90nm technology design rules was found in simulation. Simulation results are confirmed by empirical data.