Development of practical flare correction tool for full chip in EUV lithography

Abstract

A practical flare-aware optical proximity correction (OPC) tool for full-chip level has been developed for upcoming extreme ultraviolet lithography (EUVL). The conventional flare-aware OPC method for EUVL is unsuitable for practical use because it requires enormous time for lithography simulation to compensate for the long-range flare effect. By separating the lumped flare-aware OPC step into (1) the OPC step and (2) the flare correction step, the runtime required for lithography simulation is reduced to 1% by applying the same OPC for the identical pattern at different positions in step 1. And we found that there is a linear relation between amount of flare and correction bias for each pattern variation. Using this relation, a fast rule-based correction method can be adopted in step 2 without deterioration of correction accuracy for any pattern variation. Our new correction tool reduces the run-time to 1/70, which means it is the same as in the case of optical lithography for full-chip level, and also satisfies the target OPC residual of ±1nm. Consequently, it has been demonstrated that our new correction is practical and promising for the full-chip in EUVL in terms of run-time and correction accuracy.