Impact of Chip, Package, and Set Design on Transient Temperature in Mobile Application

Recently, the power density has been increasing due to the high bandwidth of 5G mobile devices and it leads to temperature rise. Increased temperature reduces lifetime by quality deterioration and degrade performance with thermal throttling. Therefore, thermal design is more important to increase lifetime and performance in limited environment. Typically, thermal analysis is conducted one by one for concerning parameter, but it cannot give us insight systematically because sensitive analysis for single parameter is not enough to get globally optimal solution. In this paper, we present transient thermal sensitivity approach (TTSA) to see the effect of design parameter on total thermal resistance for packages synthetically. As an example, Single Chip Package (SCP) and Package on Package (POP) is used, and chip thickness, thermal conductivity of Epoxy Modeling Compound (EMC) and Thermal Interface Material (TIM) was varied as a design parameter. Our simulation results show that chip level thermal solution is dominant for both POP and SCP. In case of SCP, package and set level thermal solution is effective when operating time is long enough for heat to arrive at package and set structure. With TTSA, package thermal designer can obtain the direction of package design directly.