Electromigration- and Parasitic-Aware ILP-Based Analog Router

Abstract

Interconnect and via failures due to the electromigration (EM) effect have become increasingly challenging in the advanced technology as a result of shrinking feature size. The parasitic effect, which has to be normally represented as analog and radio frequency (RF) circuit constraints for effective suppression in practice, has also made the modern physical design more intractable. In this paper, we present a new integer-linear-programming-based EM-aware and sensitivity-aware analog/RF router, which can effectively address the EM constraints as well as interconnect parasitics and matching constraints along the routing paths. Interconnect parasitics can be evaluated in the sensitivity analysis so that an appropriate width can be adopted for each subnet in order to gain better circuit performance. Any mismatch can be also minimized between ideally matching nets whenever the primitive methods fail to find exactly matched routes for these sensitive nets. By using our proposed routing methodology, the EM constraints are taken into account to guarantee a final EM-compliant routing solution. The experimental results show that our proposed method is able to produce better circuit performance compared to the previous works while EM can be seriously addressed for analog/RF circuits.