Electromechanical system having a controlled atmosphere, and method of fabricating same

• US 8,018,077 B2
• Filed: 03/13/2009
• Issued: 09/13/2011
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Partridge, Aaron, Lutz, Markus, Kronmueller, Silvia
• Primary Examiner(s): LOUIE, WAI SING
• Application Number:
  US12/403,468
• Publication Number:
  US 20090309175A1
• Time in Patent Office: 914 Days
• Field of Search: 257/417, 257/790, 257/795, 216/2, 216/80, 438/48, 438/50, 438/52
• US Class Current: 257/790
• CPC Class Codes: B81C 1/00293 maintaining a controlled atmosphere with processes not provided for in B81C1/00285
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer

Abstract

There are many inventions described and illustrated herein. In one aspect, the present invention is directed to a technique of fabricating or manufacturing MEMS having mechanical structures that operate in controlled or predetermined mechanical damping environments. In this regard, the present invention encapsulates the mechanical structures within a chamber, prior to final packaging and/or completion of the MEMS. The environment within the chamber containing and/or housing the mechanical structures provides the predetermined, desired and/or selected mechanical damping. The parameters of the encapsulated fluid (for example, the gas pressure) in which the mechanical structures are to operate are controlled, selected and/or designed to provide a desired and/or predetermined operating environment.

Claims

1. An electromechanical device comprising:

a chamber including a first encapsulation layer having at least one vent;

a mechanical structure, wherein the mechanical structure is disposed in the chamber; and

a second encapsulation layer, deposited over or in the vent, to thereby seal the chamber, wherein the second encapsulation layer is a semiconductor material and wherein the chamber includes at least one relatively stable gas.

2. The electromechanical device of claim 1, wherein the second encapsulation layer is deposited using an epitaxial, a sputtering or a CVD reactor.

3. The electromechanical device of claim 2, wherein the first encapsulation layer is deposited using an epitaxial, a sputtering or a CVD reactor.

4. The electromechanical device of claim 1, wherein the at least one relatively stable gas is helium, nitrogen, neon, argon, krypton, xenon or perfluorinated hydrofluorocarbons.

5. The electromechanical device of claim 1, wherein the second encapsulation layer is a silicon-bearing compound.

6. The electromechanical device of claim 5, wherein the silicon-bearing compound is at least one of monocrystalline silicon and polycrystalline silicon.

7. The electromechanical device of claim 1, wherein the relatively stable gas has a low diffusivity.

8. The electromechanical device of claim 1, further including a third encapsulation layer, disposed over the second encapsulation layer, to reduce the diffusion of the fluid from the chamber.

9. The electromechanical device of claim 8, wherein the third encapsulation layer is a metal bearing material.

10. The electromechanical device of claim 9, wherein the metal bearing material is deposited using an epitaxial, a sputtering or a CVD reactor.

11. The electromechanical device of claim 8, wherein the third encapsulation layer is at least one of monocrystalline silicon, polycrystalline silicon, silicon dioxide, BPSG, PSG, silicon nitride or silicon carbide.

12. The electromechanical device of claim 1, further including a third encapsulation layer, disposed over the second encapsulation layer, to reduce the diffusion of the fluid from the chamber, wherein the fluid includes helium, neon or hydrogen that was diffused through the second encapsulation layer and into the chamber to adjust the pressure of the fluid to be within a predetermined range of pressures.

13. The electromechanical device of claim 12, wherein the third encapsulation layer is a metal bearing material.