Bump-Less Interconnect with Room Temperature Pre-Bondable Adhesive and Solder for High Throughput Chip Stacking

In this report, a new bump-less interconnect process for chip stacking with high throughput is proposed. We developed polymer-based adhesive MA-0208 for bonding and the solder bump can be embedded by coating MA-0208. It can be pre-bonded against itself and SiO
2
at room temperature even after curing process. In this work, we demonstrated the bump-less interconnect process with MA-0208. The top chip with flat bonding surface consists of solder and MA-0208 was stacked to the bottom chip composed of SiO
2
and Cu at room temperature for 1 second pressing. After thermal compression bonding process, permanent bonding of MA-0208 to SiO
2
and solder to Cu were achieved, and good electrical connection was obtained.