Plasma assisted multichip-to-wafer direct bonding technology for self-assembly based 3D integration

We demonstrated plasma-assisted multichip-to-wafer direct bonding for self-assembly based 3D integration processes. We mainly evaluated the bonding yields and bonding strengths of dies obtained by multichip-to-wafer direct oxide-oxide bonding, and compared with wafer-to-wafer direct oxide-oxide bonding in their bonding properties. In this study, we employed thermal oxide and chemical mechanical polish (CMP)-treated oxide formed by plasma-enhanced chemical vapor deposition (PECVD) with tetraethyl orthosilicate (TEOS) as bonding interfaces, and in addition, N₂ or Ar plasmas were used for the surface activation. We finally introduce multichip-to-wafer direct oxide-oxide bonding between self-assembled dies and wafers having the PECVD-oxide layer.