Measurement and prediction of the contact conductance across epoxied copper contacts at cryogenic temperatures

Literature has demonstrated that the investigation of the contact conductance (h _c) across epoxied joints at cryogenic temperatures is important to the microelectronic, satellite and other space industries. The accurate theoretical prediction of the h _c arising across a metalepoxy interface is still being researched. Several researchers have shown that the acoustic mismatch and other theories do not agree well with experimental data This paper presents the results of an experimental and theoretical investigation of the h _c across copper/epoxy/copper contacts. From the h _c data, it was possible to extract the thermal conductivity (k) of the epoxy and the thermal boundary resistance (R _b) between the epoxy and copper. The R _b extracted from the experimental data was compared to model predictions made by the Acoustic Mismatch Model (AMM) and the Scattering Mediated Acoustic Mismatch Model (SMAMM). In the case of the AMM, the predictions underestimated the experimental values significantly. This finding is consistent with many investigations to date. The SMAMM was able to predict the experimental data very well when using an extremely small scattering time of 5×10 ^-18 s.