Low-Cost 3-D Integration of RF and Micro-Cooling Systems

A heterogeneous 3-D integration scheme of low cost Liquid Crystal Polymer (LCP) and silicon substrates with microfluidic channels and circulating water is demonstrated. Theoretical and experimental data show the applicability of this technique as a means to introduce effective active cooling in high-frequency electronics without adversely impacting their RF performance. An LCP coplanar waveguide fabricated on top of a silicon-etched microchannel with circulating water under a shielding ground plane is the vehicle to demonstrate the integration technology of this paper. The measured RF results are nearly identical with and without water in the microchannel. A water flow rate of ~12 ml/min is measured with a micropump that occupies less than 9.5 cm³ and consumes less than 1.2 W.