Resiliently packaged MEMs device and method for making same

• US 20020097952A1
• Filed: 01/25/2001
• Published: 07/25/2002
• Est. Priority Date: 01/25/2001
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Jin, Sungho, Soh, Hyongsok, Mavoori, Hareesh
• Granted Patent: US 6,711,317 B2
• Time in Patent Office: Days
• US Class Current: 385/18
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C

Abstract

In accordance with the invention, a MEMs device comprises a component layer, an actuator layer and an intervening spacer. The component layer, the spacer and the actuator layer are assembled at ambient temperature and held together in lateral alignment by resilient spring members. The spacer provides the walls of a cavity between a component and an actuator to permit movement of the component. The walls are advantageously conductive and cover the bulk of the peripheral boundary of the cavity to provide electrostatic isolation and aerodynamic isolation.

Claims

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

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

b) an actuator layer having at least one conductive path and at least one actuator for moving the component;

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

d) at least one resilient member coupled to the component layer and the actuator layer, wherein the component layer, spacer and actuator layer are held in laterally-aligned and vertically spaced relation by resilient force from the resilient member.

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

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

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

5. The MEMs device of claim 1 wherein the spacer aerodynamically isolates the mirror by blocking at least 20% of the peripheral area underlying the component.

6. The MEMs device of claim 1 wherein the component is a mirror.

7. The MEMs device of claim 1 wherein the actuator layer has a mirror image pattern of the component layer.

8. The MEMs device of claim 1 wherein the component layer comprises single crystal silicon.

9. The MEMs device of claim 1 wherein the component layer comprises polycrystalline silicon.

10. The MEMs device of claim 1 wherein the component is a mirror comprising a coating of metal.

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

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

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

15. The MEMs device of claim 1 wherein a transparent plate is disposed overlying the component layer.

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

17. The MEMs device of claim 16 wherein the walls substantially cover the peripheral area around the cavity to aerodynamically isolate the cavity.

18. The MEMs device of claim 1 wherein the resilient member is coupled to the component layer or the actuator layer by bonding.

19. The MEMs device of claim 1 wherein the resilient member is coupled to the component layer or the actuator layer by solder bonding, fusion bonding, glass frit bonding or adhesive bonding.

20. The MEMs device of claim 1 wherein the resilient member is coupled to the component layer or the actuator layer by resilient compressive force.

21. The MEMs device of claim 1 further comprising a stiffening frame disposed over the component layer.

22. The MEMs device of claim 1 wherein the resilient member is hermetically sealed to the actuator layer.

23. MEMs device of claim 15 wherein the resilient member is hermetically sealed to the actuator layer and the transparent plate to hermetically package the MEMs device.

25. The method of claim 24 wherein the of component layer and the actuator layer each have facing surfaces in a planar configuration.

26. The method of claim 24 wherein at least one of the component layer and the actuator layer has a mesa configuration.

27. The method of claim 24 wherein the component layer comprises a plurality of components comprising movable mirrors.

28. The method of claim 27 wherein the spacer forms a cavity between at least one mirror and its actuator, the cavity having walls blocking at least 20% of the peripheral area around the cavity.

29. The method of claim 24 wherein the component layer comprises single crystal silicon.

30. The method of claim 24 wherein the component layer comprises polycrystalline silicon.

31. The method of claim 24 wherein the spacer has a coefficient of thermal expansion (CTE) different from that of the component layer and the actuator layer by not more than 50%.

32. The method of claim 31 wherein the spacer material is selected from the group consisting of Si, Mo, W, Zr, Hf, Ta, Ti, Fe—

Ni alloys or Fe—

Co—

Ni alloys.

33. The method of claim 24 wherein the assembly is performed at ambient temperature.

34. An improved optical power gain equalizer system for dynamically reducing the variation of optical signal strength comprising a MEMs device according to claim 6.

35. An improved wavelength division multiplexing telecommunication system comprising a MEMs device according to claim 6.

36. An improved light signal switch for an optical telecommunication system comprising a MEMs device according to claim 6.

37. An improved variable optical attenuator for an optical telecommunication system comprising a MEMs device according to claim 6.

12. The MEMs device of 11 wherein the spacer comprises a material selected from the group consisting of Si, Mo, W, Zr, Hf, Ta, Ti, Fe—

Ni alloys or Fe—

Co—

Ni alloys.

24. A method of assembling a MEMS device at ambient temperature comprising the steps of:

a) providing a component layer comprising a frame and at least one movable component movably coupled to the frame;

b) providing an actuation layer which contains at least one actuator for moving the movable component;

c) disposing a spacer between the component layer and the actuator layer so as to provide a predetermined vertical spacing gap between them, the spacer optionally being separate from or part of the mirror layer and/or the actuator layer; and

d) coupling at least one resilient member to the component layer and the actuator layer to hold the component layer, the spacer and the actuator layer together by resilient force.