Bonding integrity enhancement in wafer to wafer fine pitch hybrid bonding by advanced numerical modelling

Abstract

This paper presents a 3D advanced numerical modelling methodology to simulate the bonding process for fine pitch TSV wafers using wafer to wafer hybrid bonding (W2W-HB) technology from thermo-mechanical viewpoint. Two critical results affecting bonding integrity, i.e. Cu to Cu bonding area and peeling stresses on both Cu to Cu and dielectric material bonding interfaces, are investigated in details. Bonding integrity could be enhanced by reducing the peeling stresses and achieving more Cu to Cu bonding area concurrently. This paper discusses some of common design and process parameters such as dishing value, annealing temperature and dwell duration, TSV pitch and depth with regard to bonding performance. The purpose of this study is to promote a better understanding on W2W-HB so that shorter development time and better bonding integrity could be achieved.