Investigating the Reliability of SnAgCu Solder Alloys at Elevated Temperatures in Microelectronic Applications

The demand for miniaturised electronic devices has led to various challenges in microelectronic industries. One of the challenge is the removal of fans in some applications, which has led to increased heat retention, thereby causing overheating. In the assembly of electronic devices, thermal interface materials (TIMs) can be used for bonding the surface between the flip chip and a heat sink base or heat spreader. Lead-free solder (Sn-Ag-Cu) alloys are becoming more popular as TIMs in electronic assembly. Therefore, these lead-free solders could fail during operation at elevated temperatures over a period of time. The reliability of lead-free TIMs is vital in sustaining the life span of an electronic device. Three Sn-Ag-Cu (SAC) solders were considered for this investigation, namely, SAC305, SAC105, and SAC396. An ANSYS design modeller was used in the design and analysis of the microelectronic application investigated. Temperature loads ranging between 100°C and 200°C were applied over a period of time during the simulation of the electronic package. The findings from the research suggested that the SAC305 solder TIMs will outperform SAC105 and SAC396 during operation. This is because SAC305 can accommodate more stress, while the strain rate is low compared to SAC105 and SAC396. In addition, the fatigue life of SAC305 was higher than that of SAC105 and SAC396 in the different temperature ranges investigated. Therefore, SAC305 is recommended as a better thermal interface material compared to SAC105 and SAC396.