Comparison of Mechanical Property and Thermal Cycling Lifetime of Sintered Cu and Sintered Ag

Die-bonding technology using a Cu sinter paste is an attractive and promising joint method for high-power devices operating at higher temperatures. However, sintering properties and quantification of bonding reliability for sintered Cu (sCu) have been rarely studied. Here, we report the mechanical properties and the lifetime of thermal cycling test (TCT) towards the sCu, and a comparison material, sintered Ag (sAg). The mechanical properties such as porosity, coefficient of thermal expansion (CTE), Young's modulus, tensile strength, fatigue lifetime were measured. The TCT (-40 °C/200 °C) was also conducted. To quantitatively estimate the TCT lifetime, finite-element analysis (FEA) was used. The sCu showed higher mechanical properties than the sAg. The estimated TCT lifetime of sCu was longer than that of the sAg, and the simulated results mainly correspond to the experimental TCT results. The reason for the long TCT lifetime of sCu is the lower plastic strain of sCu due to the higher yield stress of sCu.