Liquid Surface Tension-Driven Chip Self-Assembly Technology with Cu-Cu Hybrid Bonding for High-Precision and High-Throughput 3D Stacking of DRAM

Using self-assembly technology with liquid surface tension, hybrid bonding is demonstrated with 50-μm thin chips fabricated by Plasma Dicing Before Grinding (PDBG). The surface tension of liquid droplets drives the thin chips to achieve <50-nm alignment accuracy. Critical parameters affecting self-assembly and hybrid bonding accuracy are investigated to solve challenges in trade-offs between alignment accuracy and assembly throughput for HBM fabrication.