Design Benefits of Hybrid Bonding for 3D Integration

We present electrical and thermal analyses of 3D digital designs using hybrid bonding, specifically using the design rules, and other properties, for the XPERI DBI® technology at a $\mathrm{1.6}\ \mu \mathrm{m}$ pad pitch. We also go over the advantages of hybrid bonding over thermo-compression bonding (TCB) and 2D designs. Commercial 3D physical design tools were not mature when we did this work, so we came up with a methodology that builds on 2D tools. Our design flow includes scripts for optimal assignment of bonding locations, partitioning of netlist and delay constraints, and optimization techniques that involve iterating on delay constraints. Various partitioning schemes that include targeting long nets, managing flip-flop distribution between tiers, and minimum cut partitioning using an open source tool were analyzed. Because analysis results could vary from design to design, we propose potential metrics that can be used to identify designs that may benefit from 3DIC technology. Analysis results showed that we were able to reduce routed wire length by up to 57%. Logic power and total power decreased by up to 34% and 22% respectively. Silicon area also improved by 11%.11This work was supported, in part, by Xperi. DISTRIBUTION STATE-MENT A. Approved for public release: distribution unlimited.