Multi-Chip 3D Integration Using Mechanical Interlock Bonding (MIB) Technology and Optimized TSV

The fabrication of through silicon via (TSV) and multi-chip integration are the key technologies in 3D integration and Chiplets technology. Traditional Cu-Sn solid liquid inter-diffusion bonding (SLID) technology usually needs 20–30 minutes, and the total bonding time is directly proportional to the number of chips. In this study, TSV process is optimized to lower the sidewall scallop size and fulfill conformal Cu filling of TSV. Then chips used for three-chip integration are fabricated using the optimized semiconductor process. Finally, Cu-Sn Mechanical Interlock Bonding (MIB) technology is applied for three-chip bonding. The bonding process includes twice pre-bonding at room temperature and 200°C respectively, and one-time annealing at the temperature of 260 °C. The total pre-bonding time is about 10 minutes and annealing time is 20 minutes. Resistance test results and cross-section image show electrical and mechanical interconnections have been built. The MIB technology has short total bonding time, which show great advantage in the multi-chip integration.