Cu-In Fine-Pitch-Interconnects with Enhanced Shear Strength

The heterogeneous 3D integration of temperature sensitive components requires a further development of joining processes at low temperatures. A viable approach is based on In as the low-melting component for eutectic/solid-liquid-interdiffusion (SLID) bonding. In our present study, we investigated the effect of different fluxes and processing conditions on the interconnect quality. The shear strength of the Cu-In fine-pitch interconnects was determined by shearing single-stack samples. Nearly defect-free joining zones and shear strengths up to 120 MPa indicate a high potential of the Cu-In SLID bonding technology.