A LTCC microsystem vacuum package substrate with embedded cooling microchannel and Pirani gauge

This paper reports the designing, simulation and initial experimental investigation into a LTCC vacuum microsystem package substrate acting both as a vital panel and a functional structure for compact system-in-package (SiP) integration. Design, validation and experimental results for microchannels with different planar axial shapes are presented. Experimental and simulated temperature distribution over the substrate demonstrate the effectiveness of microchannel design, with substrate temperature rise cut by over 70% compared with those without microchannels. The effect of vacuum on cooling is simulated and potential ways to enhance heat transfer are suggested. The structure and principles of a Pirani gauge integrated onto the substrate are displayed. This micro gauge is formed by wire bonded, instead of by micromachining, and is proved to be both simple and effective in in-situ vacuum measuring inside a compact package. Therefore, this substrate proves an promising option for SiP applications in defense, industrial and consumer domains demanding high packaging density and vacuum or airtight circumstances.