This article introduces the fabrication technology processes of the capacitive pressure\nsensor based on the low temperature co-fired ceramic (LTCC) material. Filling the cavity with\ndifferent materials as a sacrificial layer is mainly discussed, and two different materials are chosen in\nthe fabrication. It is found that the cavity filled with polyimide expands largely during sintering,\nwhile carbon ESL49000 material filled is more preferable to keep the cavity flat. Finally, the\nstructure leaving without an air evacuation channel is designed and tested in a built-up pressure\nenvironment, the frequency measured decreases approximately linearly with the pressure applied,\nwhich proves the design leaving no air evacuation channel advisable.
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