ECOS: Stable Matching Based Metal-Only ECO Synthesis

To ease the time-to-market pressure and save the photomask cost, metal-only ECO realizes the last-minute design changes by revising the photomasks of metal layers only. This task is challenging because the pre-injected spare cells are limited in number and in cell types. Metal-only ECO has to implement these functional and/or timing changes using available spare cells. In this paper, we propose a stable matching based metal-only ECO synthesizer, named ECOS, that can implement the incremental design changes correctly without sacrificing timing and routability. The experiments are conducted on nine industrial testcases. These testcases reflect the real difficulties faced by designers and our results show that ECOS is promising for all of them.