Collective and Gang Bonding for Three-Dimensional Integrated Circuits in Chip-on-Wafer Process

We report on a thermal compression postbonder (PB3000W) that can simultaneously bond 2-6 cubes and an eight-layer stacked integrated circuit on a wafer in a two-step bonding process. This bonder can perform both collective bonding and gang bonding. The throughput can be remarkably improved because multiple layers of chips can be pre-bonded using a pre-applied non-conductive film adhesive activated simultaneously for multiple chip layers with thermal pressure. Therefore, this bonder has a high throughput of over 7000 UPH. To perform both collective and gang bonding, this bonder is equipped with a new structure head for gang bonding, a backup stage with a pulse heater, and support stages as a heat sink and wafer holder.