Inverse lithography technology (ILT): a natural solution for model-based SRAF at 45nm and 32nm

Abstract

In this paper, we present the Luminescent's ILT approach that can rapidly solve for the optimal photomask design. We will discuss the latest development of ILT at Luminescent in the areas of sub-resolution assist feature (SRAF) generation, process-window-based ILT and mask rule compliance (MRC). Results collected internally and from customers demonstrate that ILT is not only an R&D tool, but also a tool quickly maturing for production qualification at advanced technology nodes. By enforcing the proper constraints while optimizing the masks, ILT can improve process windows while maintaining mask costs at a reasonable level.