Wafer Level High Density Hybrid Bonding for High Performance Computing

Abstract

Recently, there has been an increasing use of 3D stack integration for high-performance computing applications. Wafer-to-wafer (W2W) hybrid bonding is a key technology in 3D stacking integration process. However, high-density Cu-Cu hybrid bonding interconnections between W2W can give rise to structural defects, such as misalignment and delamination during the bonding process. The testing and characterization of such defects can also be difficult and challenging. This article investigates the W2W alignment accuracy of hybrid bonding process, and studies the defects in the unbonded zone around the Cu pad bonding area.