Sensor and method for fabricating the same

• US 8,435,821 B2
• Filed: 06/18/2010
• Issued: 05/07/2013
• Est. Priority Date: 06/18/2010
• Status: Expired due to Fees

• Current Assignee: Amphenol Thermometrics, Inc. (Amphenol Corporation)
• Original Assignee: General Electric Company
• Inventors: Gamage, Sisira Kankanam, Mantravadi, Naresh Venkata, Klitzke, Michael, Cookson, Terry Lee
• Primary Examiner(s): Lee, Cheung
• Application Number:
  US12/818,611
• Publication Number:
  US 20110308324A1
• Time in Patent Office: 1,054 Days
• Field of Search: 438/411, 257/E21.536
• US Class Current: 438/53
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81C 1/00182 Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers
• 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 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A sensor and method for fabricating a sensor is disclosed that in one embodiment bonds an etched semiconductor substrate wafer to an etched device wafer comprising a silicon on insulator wafer to create a suspended structure, the flexure of which is determined by an embedded sensing element to measure absolute pressure. Interconnect channels embedded in the sensor facilitate streamlined packaging of the device while accommodating interconnectivity with other devices.

Claims

1. A method for fabricating a sensor comprising the steps of:

forming a diaphragm cavity that extends into the top surface of a substrate wafer, the top surface of the substrate wafer comprising silicon;

bonding said silicon top surface of said substrate wafer directly to the bottom surface of as device wafer, the bottom surface of the device wafer comprising silicon, without an intermediate insulating layer forming a diaphragm over said diaphragm cavity, wherein said device wafer comprises a device layer whose silicon bottom surface forms the silicon bottom surface of the device wafer, a handle, and an insulator layer located between said device layer and said handle;

removing said handle and said insulator layer from said device wafer;

placing a sensing element, in said device layer proximate said diaphragm to sense flexure in said diaphragm; and

forming an interconnect channel by removing a portion of said device layer.

2. The method for fabricating a sensor of claim 1, wherein the step of forming an interconnect channel further comprises the step of removing a portion of said substrate wafer.

3. The method for fabricating a sensor of claim 1, further comprising the step of forming a metallization layer that fits at least partially within said interconnect channel.

4. The method for fabricating as sensor of claim 1, wherein said sensing element is a piezoresistive sensing element.

5. The method for fabricating a sensor of claim 1, wherein said substrate wafer comprises a double side polished semiconductor wafer.

8. The method for fabricating a sensor of claim 1, wherein said sensor measures absolute pressure.

10. The method for fabricating a sensor of claim 1, wherein the step of forming a diaphragm cavity that extends into the top surface of a substrate wafer comprises forming a V-shaped diaphragm cavity haying tapered sidewalls that join together in the substrate wafer.

6. The method for fabricating a sensor of claim wherein said substrate wafer comprises a device layer, an insulator layer, and a handle, wherein said insulator layer is located between said device layer and said handle.

7. The method for fabricating a sensor of claim 6, further comprising the step of removing said handle and said insulator layer from said substrate wafer.

9. The method for fabricating, a sensor of claim wherein the thickness of said device layer determines the sensitivity of said sensor.