DFM: linking design and manufacturing

Until the move to the 130nm node, yield was an issue only for product engineers and engineers on the production line. Design engineers did not need to think explicitly about yield, or understand the manufacturing process. Beginning at the 130nm node, yield has become more problematic, and the defect mechanisms that contribute to yield loss are very different. Where random defects used to be dominant, we now have defects due to lithographic issues, and pattern (or design) dependent issues. This paper explains how these latter defect mechanisms differ from random defects and how and why the design engineer needs to become involved to mitigate the problem. On the lithography topic, this paper briefly examines techniques such as OPC (optical proximity correction) and PSM (phase shift masking), and explain their design and yield impact. We also examine issues such as dummy metal fill for CMP, redundant via insertion, as ways to mitigate pattern dependent yield issues.