Temporary spin-on glass bonding technologies for via-last/backside-via 3D integration using multichip self-assembly

In this study, we proposed and demonstrated self-assembly-based via-last/backside-via 3D integration using a temporary spin-on glass (SOG) bonding technology. A hydrogenated amorphous silicon (a-Si:H) was employed as a debonding layer. Known good dies (KGDs) were precisely self-assembled right side up on an electrostatic carrier wafer by surface tension of water, and then, the KGDs were fixed by applying DC voltage to the carrier. After that, the KGDs were temporarily bonded and transferred to another support glass wafer on which the a-Si:H and SOG layers were deposited. After multichip thinning, Cu-TSVs were formed on the KGDs. The resulting TSV daisy chains showed good electrical characteristics. The KGDs can be debonded with a 308-nm laser and transferred again to target interposer wafers.