Line-End Roundness and Voids Improvement of BEOL Metal Layer

Cu Voids are a common defect frequently occurred in BEOL metal layer of any technology. According to the characteristic of orientation, location and formation mechanism, it can be divided into several types such as line end voids, line voids, island voids, seam voids and so on. Increase of line end roundness can improve the Cu fill performance and decrease the occurrence of line end voids. In this paper, methods to enhance the line end roundness are demonstrated from several OPC aspects. An effective verify approach to detect the non-round line end is also discussed. Combining effective OPC approach and verify method can avoid more voids and rapidly improve BEOL yield.