MEMS device with integrated optical element

• US 20070285761A1
• Filed: 01/23/2007
• Published: 12/13/2007
• Est. Priority Date: 01/27/2006
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Zhong, Fan, Wang, Chun-Ming, Zee, Stephen
• Granted Patent: US 7,652,814 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

MEMS devices are fabricated by a method that involves forming an optical element (e.g., etalon) over a substrate and then forming a light modulating element (e.g., interferometric modulator) over the optical element. In an embodiment, a support structure for the light modulating element is aligned with the underlying optical element to thereby alter the appearance of the support structure to a viewer. Such an optical element is separated from the support structure by one or more buffer layers.

Claims

1. A spatial light modulator comprising:

a substrate;

an optical element over the substrate;

a buffer layer over the optical element; and

a light modulating element over the buffer layer, wherein the light modulating element comprises a support directly aligned with the optical element.

2. The spatial light modulator of claim 1, wherein the optical element is an etalon.

3. A MEMS device comprising:

a substrate;

an etalon over the substrate;

at least one buffer layer over the etalon; and

a light modulating element on the buffer layer, wherein the light modulating element comprises a support aligned with the underlying etalon.

4. The MEMS device of claim 3, wherein the etalon is electrically insulated from the light modulating element.

5. The MEMS device of claim 3, wherein the etalon comprises a first reflective layer, a second reflective layer, and a dielectric layer sandwiched between the first and the second reflective layers.

6. The MEMS device of claim 5, wherein the second reflective layer is fully reflective.

7. The MEMS device of claim 5, wherein the first and the second reflective layers each comprises a metal.

8. The MEMS device of claim 3, wherein the buffer layer comprises a dielectric material.

9. The MEMS device of claim 3 further comprising a conductive layer on top of the buffer layer.

10. The MEMS device of claim 3, wherein the light modulating element comprises an interferometric modulator.

11. The MEMS device of claim 10, wherein the interferometric modulator comprises an optical stack, a movable layer, and a cavity separating the optical stack from the movable layer.

12. The MEMS device of claim 3, wherein the support contacts the buffer layer in an area that is about the same size as the cross-sectional area of the etalon.

13. The MEMS device of claim 3, wherein the support comprises a post.

14. A method of making a MEMS device, comprising:

providing a substrate;

fabricating an etalon on the substrate;

forming at least one buffer layer over the etalon; and

forming a support on the buffer layer, wherein the support is aligned with the underlying etalon.

15. The method of claim 14, wherein fabricating the etalon comprises:

forming a sandwich stack over a portion of the substrate, wherein the sandwich stack comprises a first reflective layer, a second reflective layer, and a dielectric layer between the first and second reflective layers; and

removing a portion of the sandwich stack.

16. The method of claim 14, wherein fabricating the etalon comprises:

depositing a first reflective layer on at least a portion of the substrate;

removing a portion of the first reflective layer to form a recess;

depositing a dielectric layer over the first reflective layer and over the recess;

depositing a second reflective layer over the dielectric layer; and

removing at least a portion of the second reflective layer from over the recess.

17. The method of claim 14, wherein forming at least one buffer layer comprises:

depositing a dielectric layer on the etalon;

forming a planarization layer on the dielectric layer; and

removing the planarization layer and a part of the dielectric layer.

18. The method of claim 17, wherein removing the planarization layer and the part of the dielectric layer comprises etching to form a substantially flat buffer layer.

19. The method of claim 14, further comprising forming at least a light modulating element on the buffer layer.

20. The method of claim 19, wherein forming the light modulating element comprises:

forming a first reflective layer on the buffer layer;

forming a second reflective layer over the first reflective layer; and

forming a cavity between the first reflective layer and the second reflective layer, wherein the second reflective layer is supported over the first reflective layer by the support.

21. A MEMS device made by the method of claim 14.

22. A MEMS device comprising:

a means for transmitting or reflecting light;

a means for modulating light transmitted through or reflected from the transmitting or reflecting means;

a means for supporting at least a portion of the light modulating means over the transmitting or reflecting means;

a means for absorbing at least a portion of the light transmitted through or reflected from the transmitting or reflecting means; and

a means for separating the light absorbing means from the supporting means.

23. The MEMS device of claim 22, wherein the transmitting or reflecting means comprises a substrate.

24. The MEMS device of claim 22, wherein the light modulating means comprises an interferometric modulator.

25. The MEMS device of claim 22, wherein the supporting means comprises a post.

26. The MEMS device of claim 22, wherein the light absorbing means comprises an etalon.

27. The MEMS device of claim 22, wherein the separating means comprises one or more dielectric layers.

28. A MEMS display device comprising:

a substrate;

a plurality of etalons on the substrate;

at least one buffer layer over the plurality of etalons; and

an array of interferometric modulators on said buffer layer, wherein said array comprises a plurality of supports configured to align with the plurality of etalons.

29. The MEMS display device of claim 28, comprising:

a processor that is configured to communicate with the array, the processor being configured to process image data; and

a memory device configured to communicate with the processor.

30. The MEMS display device of claim 29, further comprising a driver circuit configured to send at least one signal to the array.

31. The MEMS display device of claim 30, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

32. The MEMS display device of claim 29, further comprising an image source module configured to send the image data to the processor.

33. The MEMS display device of claim 32, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

34. The MEMS display device of claim 29, further comprising an input device configured to receive input data and to communicate the input data to the processor.