Low-temperature joining of semiconductor substrates and thin layers on solid and flexible wafers by solid-liquid inter-diffusion bonding using a low-thickness Ni-Sn system

In this study, we investigate the conditions of bonding by implementing Transient Liquid Phase of the metal technique in order to secure a flexible polyimide sheet to different semiconductor substrates (Si, SOI, InP). We test the TLP bonding using Ni and Sn as filler and parental metals at low thicknesses (from 300 nm/600 nm to 1.5 μm/3 μm, for Ni/Sn respectively). At these conditions, we highlight a discrepancy with the expected behavior, especially above 280°C.