A Novel Photosensitive Polyimide Adhesive Material for Hybrid Bonding Processing

Cu/insulating material hybrid bonding technology was a promising process for high performance three-dimensional integrated package. A novel polyimide (PI) and thermal compression bonding (TCB) process were proposed for chip to wafer hybrid bonding. The new PI was developed by re-designing key components of the formulation. It showed high adhesion after TCB and high reliability performance. For the PI to PI bonding process evaluation, there were not any visible voids after pre-bonding at 250-350 degrees C and after TCB at 300 degrees C. Cu/PI co-planarization process was confirmed, and the PI showed a practical removal rate even though the PI was cured at high temperature. Furthermore, the PI showed highly smooth surface after CMP.