Pressure sensor with two membranes forming a capacitor

• US 6,662,663 B2
• Filed: 04/10/2002
• Issued: 12/16/2003
• Est. Priority Date: 04/10/2002
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Chen, Chien-Hua
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Ellington, Alandra
• Application Number:
  US10/120,944
• Publication Number:
  US 20030192383A1
• Time in Patent Office: 615 Days
• Field of Search: 737/18, 737/15, 737/24, 731/94, 737/26, 737/27, 737/30, 219/522, 219/203, 219/543, 318/483, 318/587, 318/130, 361/283, 361/284, 361/706
• US Class Current: 73/718
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm

Abstract

A pressure sensor may include a first membrane that flexes in response to pressure, a reference cavity covered by the first membrane where the reference cavity contains a vacuum and a second membrane, adjacent to the first membrane, the first and second membranes forming a capacitor having a capacitance that varies in accordance with the flexing of the first membrane and the pressure.

Claims

1. A pressure sensor comprising:

a first membrane that flexes in response to pressure;

a reference cavity covered by said first membrane, said reference cavity containing a vacuum; and

a second membrane adjacent to said first membrane and not within said reference cavity, said first and second membranes forming a capacitor having a capacitance that varies in accordance with the flexing of said first membrane and said pressure;

wherein said first and second membranes are formed in a silicon substrate; and

further comprising a polysilicon anchor on both edges of said first membrane securing said first membrane in said silicon substrate.

2. A pressure sensor comprising:

a first membrane that flexes in response to pressure;

a reference cavity covered by said first membrane, said reference cavity containing a vacuum; and

a second membrane adjacent to said first membrane and not within said reference cavity, said first and second membranes forming a capacitor having a capacitance that varies in accordance with the flexing of said first membrane and said pressure;

wherein said first membrane has a curvature that curves toward said second membrane.

3. A pressure sensor comprising:

a first membrane that flexes in response to pressure;

a reference cavity covered by said first membrane, said reference cavity containing a vacuum; and

a second membrane adjacent to said first membrane and not within said reference cavity, said first and second membranes forming a capacitor having a capacitance that varies in accordance with the flexing of said first membrane and said pressure;

wherein said first membrane has a curvature that curves away from said second membrane.

4. A pressure senior comprising:

a first membrane that flexes in response to pressure;

a reference cavity covered by said first membrane, said reference cavity containing a vacuum;

a second membrane adjacent to said first membrane and not within said reference cavity, said first and second membranes forming a capacitor having a capacitance that varies in accordance with the flexing of said first membrane and said pressure;

an upper substrate; and

a lower substrate;

wherein said first and second membranes are supported between and bonded to said upper and lower substrates; and

wherein opposite edges of each of said first and second membranes are bonded respectively to said upper and lower substrates.