A methodology for fast and accurate yield factor estimation during global routing

In this paper, a novel and computationally efficient methodology to accurately estimate key yield factors during the global routing stage is presented. Such an yield factor estimator at the global routing stage is essential since it can used to either get an early estimate of the final yield of the same design (i.e. the yield after applying the required sequence of detailed routing and post-routing yield optimizations) and/or to improve the final yield of the design by making the solution at the end of global routing more amenable to post-routing yield optimizations. The proposed yield factor estimator is inherently flexible and can easily be programmed to estimate during global routing a variety of key yield factors of the same design after a typical sequence of detailed routing and representative post-routing yield optimizations has been applied. Examples are provided to show how the yield factor estimator can be used to predict short and open critical area and metal density after typical yield optimization solutions like wire-spreading, wire-widening and metal filling, respectively. Experimental results presented in the paper show that the proposed yield factor estimator can predict final yield factor hotspots/values with a high degree of accuracy. The proposed estimator is also shown to be more suited for the purpose of yield factor estimation compared with typical metrics at the global routing stage like congestion.