A New Flexible Algorithm for Random Yield Improvement

This paper presents a new and improved solution for random yield improvement at the post-routing stage. The proposed solution is better suited for current processes, where a clustering effect has been observed resulting in differing particle densities in the metal and empty regions of the chip. To account for this clustering effect, we introduce the concept of weighted critical area to serve as a proxy for random yield loss. A new algorithm for weighted critical area minimization is also introduced. The proposed optimization solution derives a weighted critical area based on the user-specified particle densities. It then uses this weighted critical area information to dynamically select the appropriate critical area reduction technique in each local region to guarantee a reduction of the weighted critical area in both the local region and the whole layer. This makes the algorithm flexible and readily applicable to different process lines. It consistently improves the random yield irrespective of the particle densities in the metal and empty regions of the chip.