Wafer bonded pressure sensor
First Claim
Patent Images
1. A pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
- a first wafer substrate with a front side and an opposing back side, a chamber partially defined by a flexible membrane formed on the front side and at least one hole etched from the back side to the chamber;
a second wafer on the back side of the first wafer to seal the at least one hole;
wherein,the chamber contains a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; and
,associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure;
wherein,the second wafer is wafer bonded to the first wafer substrate.
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Accused Products
Abstract
A pressure sensor (30) for sensing a fluid pressure in harsh environments such as the air pressure in a tire, by using a first wafer substrate (32) with a front side and an opposing back side, a chamber (58) partially defined by a flexible membrane (50) formed on the front side and at least one hole (33) etched from the back side to the chamber (58);
- a second wafer (31) on the back side of the first wafer (32) to seal the at least one hole (33); wherein,
- the chamber (58) containing a fluid at a reference pressure, such that the flexible membrane (50) deflects due to pressure differentials between the reference pressure and the fluid pressure; and,
- associated circuitry (34) for converting the deflection of the flexible membrane (50) into an output signal indicative of the fluid pressure; wherein,
- the second wafer (31) is wafer bonded to the first wafer substrate (32).
Wafer bonding offers an effective non-adhesive solution. It provides a hermetic seal with only minor changes to the fabrication procedure. Skilled workers in this field will readily understand that the most prevalent forms of wafer bonding are:
- direct wafer, or silicon fusion, bonding;
- anodic, or electrostatic Mallory process bonding; and,
- intermediate layer bonding.
22 Citations
43 Claims
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1. A pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
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a first wafer substrate with a front side and an opposing back side, a chamber partially defined by a flexible membrane formed on the front side and at least one hole etched from the back side to the chamber; a second wafer on the back side of the first wafer to seal the at least one hole;
wherein,the chamber contains a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; and
,associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure;
wherein,the second wafer is wafer bonded to the first wafer substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification