Hierarchical placement for power hybrid circuits under reliability and wireability constraints

While a PHC (power hybrid circuit) laid out for optimizing reliability could be unroutable or extremely time consuming, a PHC laid out for optimizing wireability could have poor reliability. Therefore, to obtain a better placement, one must consider reliability and wireability at the placement stage. This study presents a tradeoff between the two objectives through a hierarchical design. The components with higher heat dissipation rate are evenly distributed to reduce both the maximum temperature and the maximum temperature variation on the substrate. For other components, the placement objective is to optimize the wireability. Since the placement procedure considers both reliability and wireability, it improves circuit reliability, and only slightly increases the total wiring lengths when compared to the force-directed placement algorithm