Regularization in inverse lithography: enhancing manufacturability and robustness to process variations

Abstract

Inverse lithography, as a mask design tool, has the capability of producing unintuitive patterns with topologies much different from those obtained from either rule-based or model-based optical proximity correction (OPC). These mask patterns may have the advantage of producing circuit patterns that are otherwise very difficult to achieve; on the other hand, the mask may be too complicated that renders it impossible to manufacture, or that, the cost of producing it would be astronomical. There is also good likelihood that the resulting circuit patterns may be severely affected when there are process variations, such as in focus or dose. In this work, we discuss how various regularization techniques may be employed to tackle these two problems: simplifying the mask pattern in an inverse lithography process, and incorporating robustness explicitly in the design algorithm. ©The Electrochemical Society.