3D integration by Cu-Cu thermo-compression bonding of extremely thinned bulk-Si die containing 10 μm pitch through-Si vias

Abstract

Using standard single damascene type techniques on bulk-Si, combined on one hand with extreme wafer thinning and on the other with Cu-Cu thermo-compression bonding technology, the paper demonstrate yielding 10k through-wafer 3D-via chains with a via pitch of 10μm for a via diameter of 5μm. The bonded contacts exhibit shear strengths exceeding 40MPa. Measurements indicate there is no significant contact resistance at the Cu-Cu bonded interface: within measurement accuracy, the 4-point via chain resistance is consistent with bulk Cu resistivity