Direct Die to Wafer Cu Hybrid Bonding for Volume Production

Hybrid bonding has been widely used in CMOS image sensor with wafer-to-wafer process (W2W), and is now, due to the fact of continuously advancement in node/CMOS scaling, extending further to IC Logic application such as High Performance Computing (HPC) and data center market with 3D advanced packaging by means of die to wafer (D2W) Hybrid. By considering the bond interface nature (direct bonding among 2 active surface) and bond pad size (down to 5μm, to 2 μm or even sub-micron size), process challenges and requirements is far beyond the traditional back-end assembly and is closed to front-end. Among those, cleanliness on both device material and assembly environment, and placement accuracy is especially critical. On the other hand, besides the quality, how to achieve good production yield and acceptable overall cost-of-ownership (CoO) is getting essential by soon entering High Volume Manufacturing (HVM). In this paper, it demonstrates a complete process for Direct D2W Hybrid Bonding, including die cleaning, surface activation, high prevision die to wafer (D2W) die bonding and annealing. HVM equipment will be used in critical process such as die preparation and die bonding.