Study of High-Speed Bonding Process with Thin Adhesive for Chiplet Heterogenous Integration

To realize high-volume manufacturing in chiplet heterogenous integration, a high-speed chip bonding process for the Chip-on-Wafer (COW) process has been developed. For dynamic mechanical evaluation, a stress relaxation test was performed. An epoxy-based adhesive exhibited viscoelastic deformation, which means the adhesive thickness decreased with elapsed time. In a bonding test, a uniform adhesive thickness of 4.9±0.5 μm was achieved with no crack damage for the Si dies observed. The bonding process with a thin adhesive showed 4-times higher throughput compared with thermal compression bonding.