Intrinsic thermal interfacial resistance measurement in bonded metal–polymer foils

Abstract

Heat conduction through bonded metal-polymer interfaces often limits the overall heat transfer in electronics packaging, batteries, and heat recovery systems. To design the thermal circuit in such systems, it is essential to measure the thermal interfacial resistance (TIR) across ~1-100 μm junctions. Previously reported TIR of metal-polymer junctions utilize ASTM E1530-based twoblock systems that measure the TIR by applying pressure across the interface through external heating and cooling blocks. Here, we report a novel modification of the ASTM-E1530 technique that employs integrated heaters and sensors to provide an intrinsic TIR measurement of an adhesively bonded metal-polymer junction. We design the measurement technique using finite element simulations to either passively suppress or actively compensate the lateral heat diffusion through the polymer, which can minimize the systematic error to ≲5%. Through proof-of-concept experiments, we report the TIR of metal-polymer interfaces made from DuPont's Pyralux doubleside copper-clad laminates, commonly used in flexible printed circuit boards. Our TIR measurement errors are <10%. We highlight additional sources of errors due to non-idealities in the experiment and discuss possible ways to overcome them. Our measurement technique is also applicable to interfaces that are electrically insulating such as adhesively-joined metal-metal junctions and sputter-coated or welded metal-polymer junctions. Overall, the technique is capable of measuring TIR ≳10 -5 m 2 KW -1 in bonded metal-polymer foils, and can be tailored for in situ measurements in flexible electronics, circuit packaging, and other hybrid metal-polymer systems.

Advances in thermal contact resistance studies

“…Besides its invulnerability to radiation heat loss and its fast response, the 3ω method is also very reliable when working at microscopic scales. Rajagopal et al 154 proposed an improved method based on bonded metal-polymer interfaces. Using a more comprehensive test section to reduce fabrication complexities, a higher amperage can be applied to reduce systematic errors.…”

Cellular Thermometry Considerations for Probing Biochemical Pathways

“…On the other hand, continuum models such as finite element methods (FEM) approximate the temperature discontinuity across dissimilar interfaces using the interfacial resistance as an input parameter [48], [54]. Typically, the thermal interfacial resistances are either measured experimentally [33], [54] or calculated from MD simulations [48], [53]. MD based simulations are usually limited to confined domains of few nm 2 -μm 2 and are also limited by the computational capacity to be able to model an entire cell.…”

“…(4)) using Figure 2. We use finite element simulations that were validated for interfacial resistance modeling in our previous work [40], [54], [61] and for modeling transients in the supplementary material. A nominal volumetric heat of 2.5 nW is assumed to be released per cell, which corresponds to a typical cell metabolism rate [41], [62].…”

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“…More recently, the RNM was extended to evaluate the effective elastic modulus of particulate systems. 45 While interfacial resistance can have a significant influence on the effective conductance in particle systems, [46][47][48][49][50] experimentally validated RNM simulations by Kanuparthi et al 1 demonstrated that spatial arrangement of particles play a very significant role in transport of heat in high contrast composites. The overall effective thermal conductivity can be accurately described if an appropriate statistical distribution of filler-matrix gap is captured.…”