Performance-driven OPC for mask cost reduction

Abstract

With continued aggressive process scaling in the subwavelength lithographic regime, resolution enhancement techniques (RET) such as optical proximity correction (OPC) are an integral part of the design to mask flow. OPC adds complex features to the layout, resulting in mask data volume explosion and increased mask costs. Traditionally the mask flow has suffered from a lack of design information, such that all features (whether critical or non-critical) are treated alike by RET insertion. Gupta et al. (2003) proposes to exploit design information (timing slacks) to reduce OPC data volume, but has a number of impractical aspects. In this paper, we propose an implementable flow that drives model-based OPC explicitly by timing constraints, with the objective of reducing mask data volume and OPC runtime. We apply a mathematical programming based slack budgeting algorithm to determine edge placement error (EPE) tolerance budgets for all polysilicon gate geometries. These tolerances are then enforced by a commercial OPC tool to achieve up to 24% MEBES data volume and 41% OPC runtime reductions on a suite of six testcases implemented in Artisan TSMC 0.13 /spl mu/m libraries.