Movable MEMS-based noncontacting device

• US 20040223686A1
• Filed: 03/01/2004
• Published: 11/11/2004
• Est. Priority Date: 07/03/2001
• Status: Active Grant

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: PTS Corporation
• Inventors: Roth, Richard, Staple, Bevan
• Granted Patent: US 7,030,537 B2
• Time in Patent Office: Days
• US Class Current: 385/18
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0008 Structures for avoiding electrostatic attraction, e.g. avoiding charge accumulation
• 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 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3548 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3558 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/3566 involving bending a beam, e.g. with cantilever
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system

Abstract

A microstructure for steering light that mitigates stiction problems is provided. A first tiltable assembly that includes a reflective coating is connected with a substrate. A second tiltable assembly is also connected with the substrate. First hand second electrodes are connected with the substrate and are configured to tilt the two tiltable assemblies such that they are interdigitated. In various embodiments, the tiltable assemblies are configured as cantilever arrangements and/or torsion-beam arrangements.

Claims

1. A movable microstructure comprising:

a first tiltable assembly formed over a substrate;

a second tiltable assembly formed over the substrate; and

first and second electrodes respectively positioned relative to the substrate to tilt the first and second tiltable assemblies upon activation such that the first and second tiltable assemblies are interdigitated.

2. The microstructure recited in claim 1 wherein the first tiltable assembly is configured as a cantilever arrangement.

3. The microstructure recited in claim 2 wherein the second tiltable assembly is configured as a torsion-beam arrangement.

4. The microstructure recited in claim 1 wherein the second tiltable assembly is configured as a torsion-beam arrangement.

6. The microstructure recited in claim 1,

wherein the first tiltable assembly includes:

a first structural linkage formed over the substrate;

a first structural film supported by the first structural linkage and having a plurality of fingers at an end of the first structural film; and

wherein the second tiltable assembly includes;

a second structural linkage formed over the substrate; and

a second structural film supported by the second structural linkage and having a plurality of fingers at an end of the second structural film.

7. The microstructure recited in claim 6 wherein the first and second electrodes comprise polysilicon.

8. The microstructure recited in claim 6 wherein the first and second structural films comprise polysilicon.

9. The microstructure recited in claim 6 wherein the first structural linkage has a greater height above the substrate than the second structural linkage.

5. (Canceled).

10. A method for fabricating a movable microstructure, the method comprising:

forming a first tiltable assembly over a substrate;

forming a second tiltable assembly over the substrate; and

forming first and second electrodes relative to the substrate to tilt the first and second tiltable assemblies upon activation such that the first and second tiltable assemblies interdigitate.

11. The method recited in claim 10 wherein forming the first tiltable assembly comprises creating a cantilever arrangement.

12. The method recited in claim 11 wherein forming the second tiltable assembly comprises creating a torsion-beam arrangement.

13. The method recited in claim 10 wherein forming the second tiltable assembly comprises creating a torsion-beam arrangement.

15. The method recited in claim 10,

wherein forming the first tiltable assembly includes:

forming a first structural linkage over the substrate;

forming a first structural film on the first structural linkage, the first structural film having a plurality of fingers at an end of the first structural film; and

wherein forming the second tiltable assembly includes;

forming a second structural linkage over the substrate; and

forming a second structural film on the second structural linkage, the second structural film having a plurality of fingers at an end of the second structural film.

16. The method recited in claim 15 wherein forming the first structural linkage comprises forming the first structural linkage over the substrate at a height greater than the second structural linkage.

14. (Canceled).

17. A method for operating a movable microstructure, the method comprising:

tilting a first assembly by applying a first electrostatic force, the first assembly including;

a first structural linkage formed over a substrate; and

a first structural film supported by the first structural linkage and having a plurality of fingers at an end of the first structural film;

tilting a second assembly by applying a second electrostatic force, the second assembly including;

a second structural linkage formed over the substrate; and

a second structural film supported by the second structural linkage and having a plurality of fingers at an end of the second structural film; and

holding the first and second assemblies electrostatically in a fixed position with the fingers of the first and second structural films interdigitated.

18. The method recited in claim 17 wherein the first assembly is configured as a cantilever arrangement.

19. The method recited in claim 18 wherein the second assembly is configured as a torsion-beam arrangement.

20. The method recited in claim 17 wherein the second assembly is configured as a torsion-beam arrangement.

22. The method recited in claim 17 wherein tilting the first assembly comprises tilting the end of the first structural film having a plurality of fingers towards the substrate and tilting the second assembly comprises tilting the end of the second structural film having a plurality of fingers away from the structural assembly.

21. (Canceled).

23. A movable microstructure, the microstructure comprising:

tiltable micromirror means formed over a support means;

tiltable snare means connected with the support means; and

means for generating electrostatic forces for tilting the tiltable micromirror means and the tiltable snare means into an interdigitated configuration.

24. The microstructure recited in claim 23 wherein the tiltable micromirror means comprises cantilever means.

26. The microstructure recited in claim 23 wherein the micromirror means comprises torsion-beam means.

27-29. -29. (Canceled).