Fine-pitch interconnection by hybrid Cu/Sn-adhesive bonding for 3D integration

In this study, we developed 8 μm-pitch microbump bonding and encapsulating by hybrid Cu/Sn-adhesive bonding technology. As an adhesive material, we used a non-conductive film (NCF). To realize simultaneous bonding of a metal and an adhesive, planar structure was formed by chemical mechanical polishing (CMP). After the planarization, hybrid bonding was carried out at 250 °C for 60 s. From scanning electron microscopic (SEM) observation of the bonded sample, it was confirmed that 8 μm-pitch bump bonding and the NCF filling 2.5-μm gap between the chip and substrate were performed at the same time. This result indicated that hybrid bonding was effective in fine-pitch bonding and encapsulating for future three-dimensional (3D) integration.