Claims
- 1. A pressure sensing device formed in a substrate having at least one semiconductor device formed thereon for monitoring the pressure sensing device, the pressure sensing device comprising:
- a first cavity formed beneath a first surface of the substrate;
- first pressure sensing means formed between the first cavity and the first surface of the substrate so as to be responsive to a pressure at the first surface of the substrate;
- a second cavity formed beneath the first surface of the substrate so as to be adjacent the first cavity, the second cavity being vented to a second surface of the substrate;
- second pressure sensing means formed between the second cavity and the first surface of the substrate so as to be responsive to a pressure at the second surface of the substrate;
- an oxide layer formed on an interior surface of each of the first and second cavities; and
- a polysilicon layer formed over the oxide layer so as to seal the first and second cavities from the first surface.
- 2. A pressure sensing device as recited in claim 1 wherein the first surface is a front side of the substrate and the second surface is a backside of the substrate.
- 3. A pressure sensing device as recited in claim 1 wherein a portion of the first surface of the substrate is exposed to atmospheric pressure while a portion of the second surface of the substrate is exposed to a pressure other than atmospheric pressure.
Parent Case Info
This is a division of application Ser. No. 08/059,222 filed on 10 May 1993 now U.S. Pat. No. 5,427,975.
US Referenced Citations (11)
Divisions (1)
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Number |
Date |
Country |
Parent |
59222 |
May 1993 |
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