Sn-enhanced high-temperature reliability of Cu/Nano-Ag/Cu joint via transient-liquid-phase bonding

JX Liu and WS Lv and Y Mou and Y Peng and FL Zhu and MX Chen, JOURNAL OF MATERIALS SCIENCE (2023).

DOI: 10.1007/s10853-023-08702-1

Due to the excellent thermoelectric properties and low sintering temperature, nano-Ag paste is a promising die-attach material for high power electronic device. Unfortunately, it is difficult to resolve the critical issues including poor interfacial wettability, high porosity and poor high-temperature reliability of sintered nano-Ag joint. In this study, a novel bonding method was proposed to solve these problems by introducing Sn into the nano-Ag joint through the transient-liquid-phase (TLP) bonding technology. The Ag-Sn joint reported in this paper maintained excellent mechanical properties after high temperature aging and thermal shock test. The addition of Sn reduced the porosity of nano- Ag joint and improved the wettability of bonded interface. After aging at 200 ? for 2000 h, the shear strength still remains higher than 50 MPa. Besides, this bonding approach resolves the oxidization problem of Cu substrate at high temperature. The molecular dynamics (MD) simulation results indicate the addition of Sn could effectively inhibit the permeation of oxygen into the interface.

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