P. Topart, C. Alain, L. N. L., S. Leclair, P. Desroches, B. Tremblay, H. Jerominek "Hybrid micropackaging technology for uncooled FPAs" Proc. of SPIE, 5783:544-550, 2005
Abstract: A novel concept for low-cost, wafer-level packaging of MEMS is proposed and applied to vacuum packaging of INO's 160×120 pixel uncooled bolometric focal plane arrays, FPAs, based on vanadium oxide as thermistor material. The wafer-scale fabrication of both metallic and ceramic micropackages is described. In the former case, a nickel tray composed of several tens of micropackages is electroplated by using a thick negative resist as micromold. In the latter case, micropackages are fabricated from up to 1 mm-thick, polished, laser machined alumina wafers equipped with solderable layers and solder seals. FPA dies and infrared windows are then soldered to the main tray by thermo-compression bonding. Contrary to the conventional wafer-to-wafer bonding approach, assembly and vacuum sealing steps are dissociated. For that purpose, each micropackage is equipped with a pump-out hole for outgassing prior to vacuum sealing. To monitor in-situ pressure changes within the sealed microcavity, micromachined pressure sensors were specifically designed for thermal conductance measurements. The initial characterization of dies after assembly in the metallic micropackage is presented.
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