Advanced Thermal Management Solutions on PCBs for High Power Applications

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 the rapid advances in semiconductor technology, particularly in the regime of high-power components, the temperature dependence of the long-term reliability is a critical parameter and has to be considered with highest possible care 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 (lines / 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 thicknesses. This can lead to significant component temperature and therewith 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, which 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 aim of this paper is to give a short overview about standard thermal solutions like thick copper, thermal vias, plugged vias or metal core based PCBs. Furthermore, attention will be turned on the development of copper filled thermal vias in thin board constructions. In another approach advanced thermal management solutions will be presented on the board level, exploring different buildup concepts (e.g. cavities). Advantages of cavity solutions in the board will be shown, which 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 packaging solution and show an increase in mechanical and thermal reliability. Moreover, thermal simulations will be conducted and presented in this paper in order to reduce production efforts and to offer optimized designs and board buildups.