High‐Temperature Degradation Mechanism of Interfacial Thermal Resistance Based on Submicron Silver Adhesion

Abstract Thermal interface materials (TIM) represented by submicron silver adhesive provide a promising solution for ultra‐high heat dissipation in chip integration. However, it is difficult to accurately characterize the thermal performance of submicron silver adhesive interfaces, and their high‐temperature degradation mechanism still remains unclear. Herein, the accelerated high‐temperature aging experiments of submicron silver adhesion interfaces are performed, and a non‐destructive testing method is provided to measure the degeneration of interfacial thermal resistance (ITR). After performing the two‐sided test, ITR can be extracted with an error of less than 4.6%. Based on scanning electron microscopy and X‐ray microstructural analysis, the microstructural evolution of silver adhesive interfaces is presented and its high‐temperature degradation mechanism is determined. It is observed for the first time that ITR would change with the aging time following a bathtub curve. Such a degenerative process can be evidently divided into three stages including secondary solidification, fluctuation, and failure. In addition, a physical model is developed to interpret the degradation mechanism of ITR at high temperatures. The change in the trend of submicron silver body and TIM–solid contact thermal resistance at different stages is presented. This work helps promote submicron silver's application as high‐performance TIM.