Investigation of an Embedded Cooling RF Silicon Interposer for an Ultrahigh Heat Flux GaN TR Array

Abstract

To achieveefficient thermal management with the increase in the heat flux of radio frequency (RF) microsystems, an embedded micro pin-fin flow boiling cooling RF silicon interposer was looked into. Since through-silicon via (TSV) arrays have to be constructed through micro pin-fin pillars, the cooling cavity architecture of uneven micro pin-fin arrays is defined by the TSVs’ distribution in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $ </tex-math></inline-formula> 4 RF transceiver/receiver (TR) array package. Based on the validation of a flow boiling visualization, the hydro-thermodynamic behaviors of a triangular micro pin-fin geometry might allow the detachment time of the quickest nucleation boiling bubbles. Comprehensively considering the functioning stability (single-phase flow or two-phase flow at 100 mL/min) and temperature uniformity (less than ±4.45 °C), the optimized regular (28.8 W/400 W/cm2 heat flux) and shock (64.8 W/900 W/cm2 heat flux) modes could be dependably operated for the embedded cooling RF silicon interposer to serve the RF microsystem. In addition, the analytical solutions on the wrapped TSV RF signal (4–40 GHz) vertical transmission showed good agreement (less than 0.08 dB, 0.152 variance) with the measurements. Overall, the demonstrated thermal–electric codesign verification process in this study can be applied to the embedded cooling packages used in high-power RF devices.