Simulation based Post OPC Verification to Enhance Process Window, Critical Failure Analysis and Yield

摘要

Optical Proximity Correction (OPC) often reaches its limitation, especially low-k imaging. It results in yield drop by bridging, pinching, and other process window sensitive issues. It happens more when the original layout contains OPC-unfriendly patterns. With OPC-unfriendly layout, OPC model generates totally unexpected results such as narrow space, small jog, small serif and etc. Those unexpected OPC results induce bridged patterns as well as narrow process margin. And they will give direct yield loss of device. Thus, it is critical to implement the flow for Litho Friendly Design (LFD) and nevertheless simulation-based OPC verification. In this study, a new approach of OPC has been tested, which contains the simulation based analysis of OPC failure and in turn out reconstruct OPC features in a way to fix not only bridging and pinching but also to improve process window. This proves to reduce mask respin by 50% or more. It also has been tried to be a complementary checking in addition to conventional CD monitor in pilot production.