Thermal-Mechanical Impact of Thermal Solutions in Handheld Devices

Use of Thermal Interface Materials (TIM) is a common thermal solution approach in handheld devices to reduce junction temperature and control device skin temperature. This work summarizes the thermal benefits of using a TIM for enhancing the user experience and increasing System on Chip (SoC) performance. On the other hand, TIM induces a load on the package which in turn can impose stress on the package solder joints. This paper explains the impact of a variety of parameters such as TIM material and thickness and system boundary conditions on thermal performance of the SoC/system and the load distribution on solder joints. The complexity of mechanical load distribution is discussed through extensive data collection and simulation in phone and tablet form factors. Design guidelines for selection of appropriate TIM are proposed to improve the thermal performance without compromising the reliability of the SoC package.