An experimental setup and procedure for thermal resistance measurements of a thermal interface material

A thermal interface material (TIM) is the backbone of a thermal management system for cooling functional electronic devices. Experimental measurements of interfacial thermal resistance for a particular TIM is critical to address the issue of increasing power dissipation. This paper describes a test apparatus developed for steady state thermal resistance measurements of a TIM based on one-dimensional heat conduction and Fourier's law. The primary objective was to develop a measurement system compatible with industry needs for repeatable and accurate thermal resistance measurements. This was accomplished by utilizing a low cost, disposable, thermocouple instrumented test section containing the TIM. A commercially available thermally conductive and electrically insulating epoxy adhesive was selected as the TIM to be evaluated. The experiment comprised of determining the interfacial thermal resistance of assembled test samples as a function of their measured Bond Line Thickness (BLT). An uncertainty analysis was performed to find the maximum potential variation in the thermal resistance. It was confirmed that increasing heat flow and BLT reduces the uncertainty in interfacial temperature difference thereby reducing the overall uncertainty in thermal resistance.