Magnetically-packaged optical MEMs device

• US 6,574,026 B2
• Filed: 12/07/2000
• Issued: 06/03/2003
• Est. Priority Date: 12/07/2000
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.), Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Jin, Sungho, Soh, Hyongsok
• Primary Examiner(s): CHERRY, EUNCHA P
• Application Number:
  US09/731,493
• Publication Number:
  US 20020071166A1
• Time in Patent Office: 908 Days
• Field of Search: 359/223, 359/224, 359/225, 359/226, 359/838, 359/290, 359/291, 359/872, 385/17, 385/18
• US Class Current: 359/224.1
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 7/0067 for controlling the passage of optical signals through the package
• CPC Class Codes: B81C 2203/058 Aligning components using methods not provided for in B81C2203/051 - B81C2203/052
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

In accordance with the invention, the component layer, the spacer and the actuator layer of a MEMs device are assembled at ambient temperature and held together in lateral alignment by upper and lower magnets. Such ambient temperature magnetic packaging greatly minimizes the undesirable exposure of the sensitive MEMs components to high temperatures. The resulting MEMs device exhibits the high dimensional accuracy and stability. In a preferred embodiment, the component layer comprises a layer of movable mirrors and a spacer aerodynamically and electrostatically isolates each mirror, minimizing cross-talk between adjacent mirrors.

Claims

1. A magnetically-packaged optical micro-electro-mechanical (MEMS) device comprising:

a) a mirror layer having a frame and at least one mirror, each mirror movably connected to the frames;

b) an actuator layer having at least one conductive path and at least one electrode, each electrode capable of inducing movement in the mirror;

c) at least one spacer to separate the mirror layer and the actuator layer by a vertical gap spacing, the spacing being separate from or part of the mirror layer and/or the actuator;

d) a first body of magnetic material disposed distally with respect to the mirror layer or secured thereto;

e) a second body of magnetic material disposed distally with respect to the actuator layer or secured thereto;

f) wherein the mirror layer, spacer and actuator layer are held in laterally-aligned and vertically spaced relation by magnetic attractive force between the first and second bodies of magnetic material.

2. The MEMs device of claim 1 wherein the mirror layer and the actuator layer have facing surfaces, each having a planar configuration.

3. The MEMs devices of claim 1 wherein the mirror layer or the actuator layer has a mesa configuration.

4. The MEMs device of claim 1 wherein the mirror layer, the spacer, the actuator layer, and the first and second bodies are laterally self-aligned by alignment slots, protruding features, or stepped edges present in one or more of the layers or bodies.

5. The MEMs device of claim 1 wherein the spacer aerodynamically isolates the mirror by blocking at least 30% of the peripheral area underlying the mirror.

6. The MEMs device of claim 1 wherein the first body has a cavity to allow a light signal to reach the mirror surface.

7. The MEMs device of claim 6 wherein the first body has a thickness of at least 5% of the mirror diameter.

8. The MEMs device of claim 1 wherein the first body or the second body comprises soft magnetic material having a coercive force of less than 50 Oe.

9. The MEMs device of claim 1 wherein the first body or the second body comprises permanent magnetic material having a coercive force of at least 200 Oe.

10. The MEMs device of claim 1 wherein the second body has a mirror image pattern of the first body.

11. The MEMs device of claim 1 wherein the mirror layer comprises single crystal silicon.

12. The MEMs device of claim 1 wherein the mirror layer comprises polycrystalline silicon.

13. The MEMs device of claim 1 wherein the movable mirror comprises a coating of metal.

14. The MEMs device of claim 1 wherein the spacer has a coeffecient of thermal expansion (CTE) different from the mirror layer and the actuator layer by not more than 50%.

16. The device of claim 1 wherein the first and second bodies of magnetic material are resiliently coupled.

17. The device of claim 1 wherein the range of resilient coupling is at least 5 micrometers.

18. The device of claim 1 wherein the spacer is comprised of ferromagnetic material.

19. The device of claim 1 wherein the first body is distal with respect to the mirror layer and further comprises a transparent plate disposed between the first body and the mirror layer.

20. The device of claim 1 wherein the spacer includes walls defining a cavity below the mirror and the walls are conductive to electrostatically isolate the cavity.

21. The device of claim 20 wherein the walls substantially cover the peripheral area around the cavity to aerodynamically isolate the cavity.

15. The MEMs device of 14 wherein the spacer comprise a material selected from Si, Mo, W, Zr, Hf, or Ta.

22. A optical micro-electro-mechanical (MEMS) device comprising:

a) A component layer having a frame and at least one component, each component movably connected to the frame;

b) an actuator layer having at least one conductive path and at least one electrode, each electrode capable of inducing movement of the component;

c) at least one spacer to separate the component layer and the actuator layer by a vertical gap spacing, the spacer being separate from or part of the component layer and/or the actuator layer;

d) a first body of magnetic material disposed distally with respect to the component layer or secured thereto;

e) a second body of magnetic material disposed distally with respect to the actuator layer or secured thereto;

f) wherein the component layer, spacer and actuator layer are held in laterally-aligned and vertically spaced relation by magnetic attractive force between the first and second bodies of magnetic material.

23. The MEMs device of claim 22 wherein the component layer and the actuator layer have facing surfaces, each having a planar configuration.

24. The MEMs devices of claim 22 wherein the component layer or the actuator layer has a mesa configuration.

25. The MEMs device of claim 22 wherein the component layer, the spacer, the actuator layer, and the first and second bodies are laterally self-aligned by alignment slots, protruding features, or stepped edges present in one or more of the layers or bodies.

26. The MEMs device of claim 22 wherein the spacer aerodynamically isolates the component by blocking at least 30% of the peripheral area underlying the component.

27. The MEMs device of claim 22 wherein the first body has a cavity to allow a light signal to reach the component.