Reliability analysis on epoxy based thermal interface subjected to moisture environment

A thermal challenge has been growing in microelectronics industry to dissipate more and more chip power. New thermal solutions have been developed in industry. High metal filled thermal compound is one of them. This kind of thermal compound often uses a polymer matrix such as epoxy as the metal carrier. This paper is to investigate the thermal reliability with the environmental exposure to temperature and humidity. A mathematical diffusion model with variables of temperature, humidity and exposure time is utilized to analyze the moisture content in the thermal compound. Experimental measurements on bonding strength have shown to decrease as the moisture level increases in the thermal interface bondline following an exponential curve. An acceleration model is also obtained for the moisture level in thermal interface. Combined with the mechanical modeling, the packaging products could be designed to achieve a reliable thermal performance in the field with the epoxy based thermal interface