Dead Via Minimization by Simultaneous Routing and Redundant Via Insertion

Abstract

While via failure significantly contributes to yield loss during manufacturing, post-routing redundant via insertion method is the conventional means of reducing the via failure rate, but only alive vias can be protected. As existing dead vias still lower manufacturing yield, identifying a routing result with fewer dead vias can increase the redundant via insertion rate, subsequently enhancing the yield of chips. This work presents, for the first time, a redundant-via-aware routing system to retain redundant via resources in track assignment, in which redundant vias are inserted in detailed routing. The proposed via prediction scheme performs trial route using L-shaped patterns to estimate via positions. Meanwhile, the proposed redundant-via-aware detailed router gradually relaxes the limitation on the number of generated dead vias during path searching to minimize the number of dead vias. Experimental results indicate that the proposed redundant-via-aware routing system is, to our knowledge, the first routing system that can achieve 100% redundant via insertion rate with all MCNC benchmark circuits.