Convergence-based OPC method for dense simulations

摘要

As the process of migration of Optical process correction (OPC) recipes continues to go from sparse to densecomputations, a run time effectiveness issue persists to remain for huge structures that exist in some metal and activelayers designs. Even for 45 and 32 nm technology nodes, some polygons might be several microns in width consuming avast amount of simulation time and order of magnitudes more than sparse simulations to converge. Practically, thisproblem is pronounced, which is usually the case, when the design comprises these huge structures and other smallcritical ones that needs many iterations and careful tuning to converge. And thus, a considerable amount of run time willbe wasted while applying these sophisticated recipes on big structures that could originally converge within fewiterations using a simple recipe. In this context, a convergence-based dense OPC recipe is proposed to deal with designs that have both types ofstructures. The basic idea is to check convergence prior starting next iteration and skip the rest of the iterations if thewhole simulated frame has converged within a predefined tolerance. Also, a reasonable way to define tolerances isexplored.