A vacuum/airtight package with multifunctional LTCC substrate and integrated pirani vacuum gauge for 3D SIP integration applications

This paper reports the design and initial experimental investigation of a vacuum/airtight package, based on a multilayered LTCC substrate that acts not only as a chip carrier with flexible interconnects but an integrated panel with multiple functional structure. Design, validation and experimental results for various cooling microchannels embedded into the substrate are presented; the substrate temperature rise is cut by over 70% compared with substrate without microchannels. The effect of vacuum on cooling is simulated. A hot-wire micro Pirani gauge are integrated onto the substrate by wire bonding for a simple and effective in-situ vacuum measuring. The packaged sample display a leakage rate of lower than 10^-12 Pa · m³/s. Therefore, this packaging can be an optimal choice for 3D system-in-package applications demanding high integration density, medium vacuum circumstance and long usage/storage lifecycle.