Thermal Performance of an Indium-Silver Alloy Metal TIM for a Large Body Lidded FCBGA After EOL and Long-term Reliability Tests

The power consumption required for semiconductors has increased to hundreds of watts due to the growing artificial intelligence (AI) and high-performance computing (HPC) industries. High temperatures resulting from high-power consumption can reduce the electrical performance of integrated circuit (IC) chips, therefore, effective heat dissipation is essential to enhance the chip's performance and extend its life.For thermally improved packaging solutions, the thermal interface material (TIM) is one of the key factors. A lot of TIMs, such as polymer, graphite and metal TIMs have been developed to provide the best thermal performance for packages.Among the various TIMs, a metal-based TIM with high thermal conductivity showed superior thermal performance at end-of-line (EOL) in a previous study. However, it is also important to stably maintain the excellent performance even after long-term reliability testing. This paper explains the thermal performance of Indium-Silver-based metal TIM with two long-term reliability tests as well as EOL measurements: 1) 2, 000 cycles temperature cycling (TC) test at Condition K; and 2) 2,000 hours high temperature storage (HTS) test at 135°C.Junction-to-case thermal resistance (Ө JC ) measurements of 60 body (BD) lidded Flip Chip ball grid array (FCBGA) packages were performed with water-cooled cold plate cooling system. The 60 BD lidded FCBGA thermal test vehicle (TTV) has 25.6 x 25.6 mm die divided into 36 unit-cells with the temperature of each cell measured individually.Scanning acoustic tomography (SAT) and scanning electron microscope (SEM) images were measured to correlate Ө JC results. Also, the difference of the heat flow mechanism from the die to lid between HTS and TC test conditions was also described using three-dimensional (3D) thermal simulation for further understanding the thermal characteristics of the metal TIM.