Wafer-level 3D integration using hybrid bonding

In this paper, several material candidates for hybrid bonding technology in wafer-level 3D integration were investigated. Polymer materials, including BCB, SU-8, AL-Polymer, and polyimide (PI), were studied and then thermal-compression bonded between 150°C and 450°C. Characterization of bonded layer and evaluation of bond quality for these bonded wafers were investigated by Scanning Acoustic Tomograph (SAT), dicing test, shear test, and cross-sectional SEM. To understand the behavior and physics meaning of failure bonding, the mechanism is studied to explain the relation between bonding failure and material properties. In addition, samples with hybrid scheme were fabricated to perform hybrid bonding and realize the compatibility in whole processes. The demonstration of wafer-level 3D integration using hybrid bonding is significant to prove the manufacturability of 3D IC applications.