Pressure Sensor Having Sealed And Apertured Chambers

• US 20090272196A1
• Filed: 07/09/2009
• Published: 11/05/2009
• Est. Priority Date: 10/18/2004
• Status: Abandoned Application

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Mallinson, Samuel George
• Application Number:
  US12/500,594
• Publication Number:
  US 20090272196A1
• Time in Patent Office: Days
• US Class Current: 73/729.200
• 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

A pressure sensor is provided having a substrate assembly having a first substrate bonded to a second substrate via an intermediate bonding layer so as to define sealed channels in the first substrate, a sealed reference chamber on said first substrate and having the sealed channels, and an apertured chamber on said first substrate and covering the sealed reference chamber.

Claims

1. A pressure sensor comprising:

a substrate assembly having a first substrate bonded to a second substrate via an intermediate bonding layer so as to define sealed channels in the first substrate;

a sealed reference chamber on said first substrate and having said sealed channels; and

an apertured chamber on said first substrate and covering the sealed reference chamber.

2. A pressure sensor as claimed in claim 1, wherein the sealed reference chamber is defined by a conductive layer on the first substrate and a conductive membrane extending from the first substrate which is spaced from the conductive layer.

3. A pressure sensor as claimed in claim 2, wherein the apertured chamber is defined by a cap having apertures which extends from the first substrate to cover the conductive membrane.

4. A pressure sensor as claimed in claim 2, wherein:

the first substrate is a silicon substrate;

a CMOS layer is deposited on the silicon substrate;

the conductive layer is deposited on the CMOS layer; and

a protective passivation layer is deposited on the conductive layer.

5. A pressure sensor as claimed in claim 4, wherein the passivation layer is formed from an insulating material.

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

7. A pressure sensor as claimed in claim 4, wherein the CMOS layer has guard rings surrounding the sealed channels to prevent air contained in the sealed channels from corroding circuitry.

8. A pressure sensor as claimed in claim 3, wherein the membrane has a peripheral portion which is located between the substrate assembly and the cap.

9. A pressure sensor as claimed in claim 8, wherein the cap has a peripheral portion on the peripheral portion of the membrane.

10. A pressure sensor as claimed in claim 1, wherein the intermediate bonding layer comprises a low melting point material.

11. A pressure sensor as claimed in claim 11, wherein the low melting point material is selected from the group consisting of:

Au—

Si;

Glass Frit;

Au—

Au;

PDMS;

TiN;

Si₃N₄;

LPCVD PSG;

APCVD BO; and

Boron-Doped Si.