Advanced Thermal Management Solutions on PCBs for High Power Applications

Abstract

With increasing power loss of electrical components, thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to rapid advances in semiconductor technology, particularly in the field of high-power components, the temperature distribution inside of a component is a critical parameter of long-term reliability and must be carefully considered during the design phase. Two main drivers in the electronics industry are miniaturization and reliability. Whereas there is a continuous improvement concerning miniaturization of conductor tracks (i.e., lines and spaces have been reduced continuously over the past years), miniaturization of the circuit carrier itself, however, has mostly been limited to decreased layer counts and base material thickness. This can lead to significant component temperature increase and thence to accelerated system degradation. Enhancement of the system reliability is directly connected to an efficient thermal management on the PCB level. There are several approaches that can be used to address this issue: optimization of the board design, use of base materials with advanced thermal performance, and use of innovative buildup concepts. The paper provides a short overview about standard thermal solutions such as thick copper, thermal vias, plugged vias, or metal core based PCBs. Furthermore, attention will be focused on the development of copper filled thermal vias in thin board construction. In another approach, advanced thermal management solutions are presented at the board level, exploring different buildup concepts (e.g., cavities). Advantages of cavity solutions in the board are shown that not only decrease the thermal path leading from the high power component through the board to the heat sink, but also have an impact concerning the mechanical miniaturization of the entire system (reduction of z axis). Such buildups serve as a favorable packaging solution with promising thermal performance. Moreover, using thermal simulations different setups are compared and a deeper insight into the thermally relevant geometry and material parameters is provided, allowing production efforts to be reduced and to offering optimized designs and board buildups.