Full-Chip Analysis of Unintentional Forward Biased Diodes

Amir Grinshpon1,  Adam Segoli Schubert1,  Ziyang Lu2
1Freescale Semiconductor, 2Mentor Graphics


Multi-power domains have become a common practice in modern VLSI designs. As the number of different operational modes and different power schemes increases, the problem of unintentional forward-biased diodes, which cause power loss and chip malfunction, has become a critical issue. In this paper, we present a novel static analysis solution to detect unintentional forward biased diodes during full-chip verification, using a device-level vector-less approach. The key feature of our method is a hierarchical Multi-Stage Filtering algorithm, which drastically reduces the runtime. Our method has been extensively tested and verified in production flows.