Transient Liquid Phase Sintering of Ni and Sn-58Bi on Microstructures and Mechanical Properties for Ni–Ni Bonding

Transient liquid phase sintering (TLPS), which is a combined bonding technology of sintering and transient liquid phase bonding, is considered to be a promising sic. die attach material owing to its excellent mechanical properties and low cost. To prevent the oxidation problem, Ni is typically plated onto direct bonded copper and sic. chip. In this study, we investigated the Ni–Ni bonding by adapting TLPS method using Ni and Sn-58Bi. The bonding temperature and time were 220 °C and 60 min, respectively. In addition, the bonding atmosphere was maintained in air without bonding pressure. To confirm the bonding reliability, high-temperature storage test was conducted at 200 °C for 1000 h. With an increase in the remelting temperature to 271 °C, the bonding strength of the TLPS joint of 20 wt% Ni case was about 15 MPa. In addition, the bonding strength decreased by approximately 32% after the high-temperature storage test for 1000 h. In conclusion, Ni–Ni bonding was successfully achieved by the TLPS of Sn-58Bi with Ni. The high-heat endurance bonding between Ni to Ni was achieved by transient liquid phase sintering bonding using Ni and Sn-58Bi. By the sintering reaction between Ni, and the intermetallic reaction of Ni, Sn, and Bi, the remelting temperature increased from 139 to 271 °C. This bonding method can be applied in SiC die attachment technology.