New chip-to-wafer 3D integration technology using hybrid self-assembly and electrostatic temporary bonding

We proposed a new chip-to-wafer 3D integration technology using hybrid self-assembly and electrostatic temporary bonding. In the hybrid self-assembly-based chip-to-wafer 3D integration (HSA-CtW), liquid surface-tension-driven chip self-assembly is combined with high-speed robotic pick-and-place chip assembly and electrostatic multichip temporary bonding. Hybrid self-assembly can realize high-throughput chip assembly of above 10,000 chips/hour with a high alignment accuracy of <; 1 μm. The electrostatic multichip temporary bonding technique enabled stress-free direct bonding of self-assembled chips. We obtained good electrical characteristics from 3D stacked chips fabricated by HSA-CtW using Cu/SnAg microbumps and Cu-TSVs.