SUPPORT STRUCTURES FOR ELECTROMECHANICAL SYSTEMS AND METHODS OF FABRICATING THE SAME

• US 20090213450A1
• Filed: 05/05/2009
• Published: 08/27/2009
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Sampsell, Jeffrey B.
• Granted Patent: US 8,081,370 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2203/0361 Tips, pillars
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• 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

A method of making an interferometric modulator element includes forming at least two posts, such as posts formed from spin-on glass, on a substrate. In alternate embodiments, the posts may be formed after certain layers of the modulator elements have been deposited on the substrate. An interferometric modulator element includes at least two spin-on glass support posts located on the substrate. In alternate embodiments, the support posts may be located over certain layers of the modulator element, rather than on the substrate. A method of making an interferometric modulator element includes forming a rigid cap over a support post. An interferometric modulator element includes support posts having rigid cap members.

Claims

1. A method of fabricating an electromechanical device, the method comprising:

forming an optical stack over a substrate;

forming a sacrificial layer over the optical stack;

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patterning the sacrificial layer to form holes;

forming a support structure located at least partially within said holes in the sacrificial layer, wherein forming a support structure comprises

depositing a first layer over the sacrificial layer,

depositing a second layer over the conformal layer, wherein the second layer comprises a different material than the first layer, and

patterning said first layer and said second layer to form a support structure; and

forming a flexible layer over the support structure, wherein the flexible layer is supported by the support structure.

2. The method of claim 1, further comprising removing the sacrificial layer to form a cavity between the flexible layer and the optical stack.

3. The method of claim 1, wherein depositing a first layer over the support structure comprises depositing a layer of conformal material over the sacrificial layer.

4. The method of claim 1, wherein the support structure comprises an insulating material.

5. The method of claim 1, wherein the support structure comprises an oxide.

6. The method of claim 1, wherein a width of the support structure increases with increased distance from the optical stack.

7. The method of claim 1, wherein the support structure comprises an outwardly extending portion located away from the optical stack

8. An electromechanical device, comprising:

an optical stack located over a substrate;

a flexible layer spaced apart from the optical stack by a gap; and

a support structure located between the optical stack and the flexible layer, wherein the support structure comprises

a first layer comprising a material more rigid than the flexible layer, and

a second layer overlying the first layer.

9. The device of claim 8, wherein the first layer of the support structure comprises a non-planarizing material.

10. The device of claim 8, wherein a width of the support structure increases with increased distance from the optical stack.

11. The device of claim 8, wherein the support structure comprises an outwardly extending portion located away from the optical stack.

12. A method of fabricating an electromechanical device, the method comprising:

forming an optical stack over a substrate;

forming a sacrificial layer over the optical stack;

forming support structures located over the substrate;

forming a flexible layer over the sacrificial layer, wherein the flexible layer is supported by the support structures; and

forming at least one overlying support structure over a portion of the flexible layer, wherein at least a portion of the at least one overlying support structure is located over a support structure.

13. The method of claim 12, wherein forming a support structure comprises:

patterning the sacrificial layer to form apertures; and

depositing the flexible layer over the sacrificial layer, wherein the flexible layer comprises a conformal layer over the sacrificial layer, and wherein portions of the flexible layer located within the apertures in the sacrificial layer form support structures.

14. The method of claim 12, wherein the overlying support structure is more rigid than the flexible layer.

15. The method of claim 12, wherein the overlying support structure comprises the same material as the flexible layer.

16. The method of claim 12, wherein the overlying support structure comprises nickel.

17. The method of claim 12, wherein the overlying support structure comprises a non-planarizing material.

18. An electromechanical device, comprising:

an optical stack located over a substrate;

support structures located over the substrate;

a flexible layer spaced apart from the optical stack by a cavity, wherein the flexible layer is supported by the support structures; and

at least one overlying support structure over a portion of the flexible layer, wherein at least a portion of the at least one overlying support structure is located over a support structure.

19. The device of claim 18, wherein the support structures comprise portions of the flexible layer which contact the optical stack.

20. The device of claim 18, wherein the overlying support structure is more rigid than the flexible layer.

21. The device of claim 18, wherein the overlying support structure comprises a non-planarizing material.