10 μm and 5 μm Die-to-Wafer Direct Hybrid Bonding

Die-To-Wafer (DTW) direct hybrid bonding process, using copper/oxide mix interfaces, is foreseen by major microelectronic industrials as essential to support Moore's law continuation, thanks to its ability to stack heterogeneous dies and to select known good die prior the bonding. This paper presents a multi-interconnection pitch test site where Cu pitch varies from 5 μm to 10 μm. The additional challenge of multipitch die bonding stands in the design rules knowledge and CMP process control to reach the surface specifications for direct hybrid bonding. After several physical characterizations before and after bonding, bonding interface quality was assessed by electrical characterization with daisy chains showing >95% yield. Preliminary results on robustness to aging tests showed very promising results with regard to thermal cycling, and high temperature storage.