Thermally isolated membrane structure

• US 7,372,115 B2
• Filed: 11/16/2005
• Issued: 05/13/2008
• Est. Priority Date: 11/16/2005
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Baney, William J.
• Primary Examiner(s): Smith; Zandra V.
• Assistant Examiner(s): Green; Telly D
• Application Number:
  US11/274,977
• Publication Number:
  US 20070108542A1
• Time in Patent Office: 909 Days
• Field of Search: 257/40, 257/414, 257/53, 257/419, 257/619
• US Class Current: 257/419
• 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: B81B 3/0081 Thermal properties

Abstract

An MEMS device including a semiconductor substrate having an upper and lower surface, and a support structure disposed at least partially in the semiconductor substrate. The support structure includes a plurality of support members oriented to define a plurality of cells in the semiconductor substrate. A thermally isolated membrane is disposed above the upper surface of the semiconductor substrate and is supported by the support structure. At least one functional component is mounted to the membrane. The plurality of cells are located substantially beneath the at least one functional component.

Claims

1. A microelectromechanical device, comprising:

a semiconductor substrate having an upper and lower surface;

a membrane support structure disposed at least partially in said semiconductor substrate, said support structure including a plurality of support members, said plurality of support members oriented to define a plurality of cells in said semiconductor substrate, each of said plurality of cells defining a cell space;

a thermally isolated membrane disposed above said upper surface of said semiconductor substrate and supported by contact with said support members; and

at least one functional component mounted to said membrane, said plurality of cells located substantially beneath said at least one functional component.

2. The microelectromechanical device of claim 1 wherein said support members comprise oxidized portions of said semiconductor substrate.

3. The microelectromechanical device of claim 1 wherein said cell space is evacuated.

4. The microelectromechanical device of claim 1 further comprising a protective layer overlying said functional components and said membrane.

5. The microelectromechanical device of claim 1 wherein said cells are rectangular in shape.

6. The microelectromechanical device of claim 1 wherein said cells are octagonal in shape.

7. The microelectromechanical device of claim 1 further comprising a cavity formed in said semiconductor substrate beneath said support structure.

8. A method of making a microelectromechanical device, comprising the steps of:

providing a semiconductor substrate having an upper surface and a lower surface;

forming a thermally isolated layer on both the upper and lower surfaces of the semiconductor substrate;

forming a plurality of support members in the upper thermally isolated layer and the semiconductor substrate, the support members defining a plurality of cells in the semiconductor substrate, each of the cells defining a cell space;

supporting a thermally isolated membrane on the plurality of support members, wherein the support members are in contact with the thermally isolated membrane; and

securing at least one functional component to the membrane at a position above the plurality of cells.

9. The method of claim 8 further comprising forming a protective layer on the membrane, the protective layer coating the at least one functional component.

10. The method of claim 8 wherein the step of forming a plurality of support members includes etching through the semiconductor substrate and the upper thermally isolated layer.

11. The method of claim 8 further including the step of forming a cavity extending into the semiconductor substrate from said lower surface, said cavity disposed beneath the plurality of cells.

12. The method of claim 8 wherein the step of forming a plurality of support members further comprises oxidizing said support members and said plurality of cells.

13. The method of claim 8 wherein said cells are rectangular in shape.

14. The method of claim 8 wherein said cells are octagonal in shape.

15. A method of making a microelectromechanical device, comprising the steps of:

providing a semiconductor substrate having an upper surface and a lower surface;

forming a plurality of support members in the semiconductor substrate defining a grid, said support members cooperating to form a plurality of cells in the semiconductor substrate, each of the plurality of cells defining a cell space;

supporting a thermally isolated membrane on the grid defined by the support members of the of the semiconductor substrate;

securing at least one functional component to the membrane.

16. The method of claim 15 further comprising forming a protective layer on the membrane, the protective layer overlying the functional components.

17. The method of claim 15 wherein the step of forming a plurality of cells includes etching into the semiconductor substrate to form the plurality of cells in the semiconductor substrate.

18. The method of claim 15, further comprising the step of forming a cavity in the semiconductor substrate and the lower thermally isolated layer, the cavity located substantially beneath the plurality of cells.

19. The method of claim 15, wherein the thermally isolated membrane is disposed on said semiconductor substrate and said plurality of support members and sealed by silicon direct bonding.

20. The method of claim 15, wherein the step of forming a plurality of support members further comprises oxidizing said support members.