High-power applications in microelectronic devices and systems is a crucial and severe issue that may cause elevated thermal and thermomechanical phenomena and finally lead the fabricated system to degradation, limitation of its performance, or even failure and destruction of its features. In specific applications, such as those found in the industry and the automotive sector, the power produced by the components may reach 50W or even higher, leading to extreme temperatures in the electronics and mechanics parts. On one hand, the integrated circuits must be able to function properly under such elevated temperatures; on the other hand effective cooling solutions, including heat-sinks, heat-spreaders, thermal interface materials, fans, etc., must be implemented. Their primal role is to remove the major part of the dissipated heat to the environment (usually air), without severely affecting the performance of the included electronic components. Such phenomena and effects can be studied prior to device and system fabrication and their behavior and influence may be depicted and analyzed thanks to design and multiphysics finite elements simulation programs; this procedure is usually time- and cost-saving, since the software tools help us discover, remove or limit major undesired issues. However, the modeling and simulation procedures require that the necessary simplification and modeling guidelines will be applied, the right material properties will be given and the appropriate boundary conditions (such as coefficient of thermal expansion, the thermal conductivity, heat capacity, etc.) will be set.
We built a high-power thermal demonstrator consisting of several heat-sources and resistors, placed on a standard PCB (printed circuit board); it functions under several Watts power, up to 35 W. On one hand, we modeled and simulated the behavior of the system with respect to the induced power and the temperature found inside the system. For that purpose, we implemented several NTC (negative temperature coefficient) resistors serving as reference points for the temperature measurements of the demonstrator. On the other hand, we managed to reduce the temperature of the test system by applying several TIM (thermal interface materials) and a set-up including a fan and a heat-sink for high-power applications. Various simulation and test cases under different flow and power conditions have been investigated and their results have been compared. Moreover, a very good numerical proximity between the simulations and the results obtained from the actual test measurements have been found. Finally, the system has been proved stable and was able to operate after several thermal cycles under 40W without any troubleshoots.
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