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Electrical capacitance pressure sensor having electrode with fixed area and manufacturing method thereof

  • US 6,584,852 B2
  • Filed: 06/24/2002
  • Issued: 07/01/2003
  • Est. Priority Date: 07/06/2001
  • Status: Active Grant
First Claim
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1. An electrical capacitance pressure sensor comprising:

  • a substrate having a first and a second surface;

    a lower electrode formed on the first surface of the substrate;

    a movable electrode formed on the lower electrode and separated by a predetermined distance from the lower electrode to form a diaphragm;

    a cavity portion formed between the lower electrode and the movable electrode to form an electrical capacitance that is to be changed when the movable electrode deforms based on an applied pressure thereon; and

    a cover member formed on the lower electrode;

    wherein the substrate has an opening portion that penetrates the substrate from the first surface to the second surface, the lower electrode has at least one window portion that penetrates the lower electrode from a side of the substrate to a side of the cavity portion and communicates the cavity portion to the opening portion of the substrate;

    the cover member is formed on a side of the opening portion of the substrate and covers the at least one window portion to separate the cavity portion from an outside thereof and to form a reference pressure chamber in the cavity portion.

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