Interfacial reaction and reliability of high temperature die attach solders for power electronics

Lead-free solder alloys for high temperature applications is required to meet increasing demands for reliable replacements for lead-based alloys. Especially, high temperature solder is required for bonding in power electronics packages where first bonding on a lead-frame is performed at a temperature of about 330 °C. In this study, the SiC based TO-220 power package was developed by applying high temperature endurable material sets which can endure over 220°C device junction temperature. The interfacial reaction and reliability of SiC die attachment on and Ni plated lead frames using Zn-Al based solder was investigated. Zn-Al-Ge solder alloy showed good temperature tolerance after temperature cycle (TC), high temperature storage test whereas Zn-Al-Ge-Mg solder alloy showed failures after TC test.