Comparison of intermetallic compound growth and tensile behavior of Sn-3.0Ag-0.5Cu/Cu solder joints by conventional and microwave hybrid heating

Microwave hybrid heating (MHH) is a possible approach for soldering; yet, the long-term reliability of solder joints is still unclear. In this work, a comparative study was carried out on the influence of isothermal aging on SAC305/Cu solder joints by conventional reflow and MHH. The conventional reflow oven was set to 260 C at 60 s holding time, and MHH was carried out at high operating power at 40 s. The reflowed sample was isothermally aged at 150 C for various aging times (0, 240, 480 and 960 h) in a laboratory oven. The conventional reflow and MHH transformed the IMC structure from scallop-like to a planar like Cu6Sn5 with a linear increase in thickness and a thin layer of Cu3Sn was observed at 240 h of aging. While Ag3Sn particles grew larger at longer aging time. The MHH shows a thinner Cu6Sn5 layer, and a smaller grain size compared to conventional reflow. The ultimate tensile strength (UTS) for conventional reflow (32.7 MPa) is 26.8% lower compared to MHH (44.7 MPa). The UTS for MHH is greater than conventional reflow as the isothermal aging time increases.(C) 2022 The Author(s). Published by Elsevier B.V.& nbsp;

Automated summary

In this study, a comparative analysis was conducted to evaluate the influence of isothermal aging on SAC305/Cu solder joints by conventional reflow and microwave hybrid heating (MHH). The results showed that MHH resulted in a thinner Cu6Sn5 layer, smaller grain size, and higher ultimate tensile strength (UTS) compared to conventional reflow, indicating its potential for improving the long-term reliability of solder joints.