Pressure Sensor With Dual Chambers

• US 20070266794A1
• Filed: 07/29/2007
• Published: 11/22/2007
• Est. Priority Date: 10/18/2004
• Status: Active Grant

• Current Assignee: Precision Mechatronics Pty Ltd
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Mallinson, Samuel
• Granted Patent: US 7,568,395 B2
• Time in Patent Office: Days
• US Class Current: 73/723
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0072 using variations in capacitance
• CPC Class Codes: G01L 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass
• CPC Class Codes: G01L 9/125 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

The present invention relates to a pressure sensor. The pressure sensor includes a substrate assembly. The substrate assembly defines sealed channels and includes a conductive layer. A conductive membrane extends from the substrate assembly and is spaced from the conductive layer to form a sealed reference chamber. A cap defines apertures. The cap extends from the substrate assembly to cover the membrane and thereby form an apertured chamber.

Claims

1. A pressure sensor comprising:

a substrate assembly defining sealed channels and having a conductive layer;

a conductive membrane extending from the substrate assembly and spaced from the conductive layer to form a sealed reference chamber; and

a cap defining apertures, and extending from the substrate assembly to cover the membrane and form an apertured chamber.

2. A pressure sensor as claimed in claim 1, wherein the substrate assembly comprises:

a silicon substrate;

a CMOS layer deposited on the silicon substrate;

the conductive layer deposited on the CMOS layer; and

a protective passivation layer deposited on the conductive layer.

3. A pressure sensor as claimed in claim 2, wherein the passivation layer is formed from an insulating material.

4. A pressure sensor as claimed in claim 2, wherein the passivation layer is formed from a semi-conducting material.

5. A pressure sensor as claimed in claim 2, wherein the CMOS layer has guard rings surrounding the sealed channels to prevent air contained in the sealed channels from corroding circuitry.

6. A pressure sensor as claimed in claim 1, wherein the membrane has a peripheral portion which is located between the substrate assembly and the cap.

7. A pressure sensor as claimed in claim 6, wherein the cap has a peripheral portion on the peripheral portion of the membrane.