Separable modulator

• US 7,672,035 B2
• Filed: 12/01/2008
• Issued: 03/02/2010
• Est. Priority Date: 12/19/1996
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence, Miles, Mark W., Sampsell, Jeffrey B., Kothari, Manish
• Primary Examiner(s): Thompson; Timothy J
• Application Number:
  US12/325,964
• Publication Number:
  US 20090080060A1
• Time in Patent Office: 456 Days
• Field of Search: 359/291, 359/290, 359/224, 359/223, 359/297, 359/298
• US Class Current: 359/291
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• 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
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/216 using liquid crystals, e.g. liquid crystal Fabry-Perot filters
• CPC Class Codes: G02F 2203/03 scattering
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

A separable modulator architecture is disclosed. The modulator has a mirror suspended from a flexible layer over a cavity. The flexible layer also forms supports and support posts for the mirror. An alternative separable modulator architecture has a mirror suspended over a cavity. The modulator is supported by supports and support posts. The support posts comprise a flexible layer over support post plugs. A bus structure may be formed upon the flexible layer arranged over the support posts.

Claims

1. A device comprising at least one light modulator, the light modulator comprising:

an electrode layer located over a substrate;

an optical stack located over the substrate;

a movable minor spaced apart from the electrode layer and optical stack by a cavity, said movable minor having a reflective surface facing the cavity; and

a flexible layer located over the movable minor and supporting the movable minor, wherein a portion of the flexible layer overlying the movable minor is spaced apart from a portion of the movable mirror by a gap.

2. The device of claim 1, additionally comprising a plurality of support posts located over the substrate, wherein the flexible layer is supported by said plurality of support posts.

3. The device of claim 2, wherein the plurality of support posts comprise a portion of the flexible layer.

4. The device of claim 2, additionally comprising at least one bus structure located over at least one of the plurality of support posts.

5. The device of claim 2, wherein the plurality of support posts comprise a planarizing material.

6. The device of claim 1, wherein the flexible layer is in contact with the movable minor at more than one location.

7. The device of claim 1, additionally comprising at least one landing pad arranged between the minor and the optical stack, wherein the landing pad comprises an insulating material.

8. The device of claim 7, wherein the landing pad is located on the 1/2 optical stack and configured to contact the minor.

9. The device of claim 7, wherein the landing pad is located on the optical stack and configured to contact the flexible layer.

10. The device of claim 1, wherein the optical stack comprises a metal layer.

11. The device of claim 1, wherein the device comprises at least two interferometric modulators, wherein a first modulator corresponding to a first color comprises a cavity having a first dimension, and wherein a second modulator corresponding to a second color comprises a cavity having a second dimension, said first and second dimensions being different.

12. The device of claim 11, wherein the device comprises at least a third interferometric modulator corresponding to a third color and comprising a cavity having a third dimension, said third dimension being different from said first and second dimensions.

13. A method of manufacturing a light modulating device, comprising:

forming an electrode layer over a substrate;

forming an optical stack over the substrate;

depositing a first sacrificial layer over the electrode layer and optical stack;

forming at least one mirror over the first sacrificial layer;

depositing a second sacrificial layer over the mirror layer;

forming a flexible layer over the second sacrificial layer; and

removing the sacrificial layers.

14. The method of claim 13, additionally comprising patterning at least said first and second sacrificial layers to form a plurality of post holes.

15. The method of claim 14, wherein forming the flexible layer comprises:

depositing a flexible layer over the second sacrificial layer; and

patterning and etching the sacrificial layer to form a plurality of supports.

16. The method of claim 15, wherein the plurality of supports have predetermined mechanical properties such that the mirror assumes a quiescent state at a predetermined vertical position from the electrode layer and optical stack.

17. The method of claim 15, wherein the plurality of supports have predetermined physical restraints that cause the mirror to move to a predetermined position relative to the electrode layer and optical stack upon application of a constant voltage.

18. The method of claim 14, additionally comprising:

depositing a layer of planarizing material prior to deposition of the flexible layer; and

partially removing the planarizing material to form a plurality of support posts.

19. The method of claim 18, wherein forming a flexible layer over the second sacrificial layer comprises forming a flexible layer over the plurality of support posts.

20. The method of claim 14, additionally comprising:

depositing a third sacrificial layer over the flexible layer; and

forming at least one bus structure over at least one of the plurality of post holes.

21. The method of claim 20, wherein forming at least one bus structure over at least one of the plurality of post holes comprises:

patterning the third sacrificial layer to form a hole located over at least one of the plurality of post holes;

depositing a conductive bus layer over the third sacrificial layer, such that the conductive bus layer fills the hole in the third sacrificial layer; and

patterning the conductive bus layer to form at least one bus structure over at least one of the plurality of post holes.

22. The method of claim 13, additionally comprising forming at least one landing pad over the optical stack.

23. The method of claim 13, wherein the optical stack comprises a metal layer.

24. The method of claim 13, wherein depositing a first sacrificial layer comprises depositing a first sacrificial layer having multiple thicknesses.

25. The method of claim 24, wherein the first sacrificial layer comprises a first portion having a first thickness, a second portion having a second thickness, and a third portion having a third thickness, and wherein at least one minor is located over each of said first, second, and third portions.

26. The method of claim 25, wherein each minor corresponds to an interferometric modulator, and wherein the thickness of the portions of the first sacrificial layer underneath the minors determines the colors reflected by the corresponding modulators.

27. A light modulator, comprising:

means for conducting an electrical signal, wherein the conducting means comprise an electrode layer formed over a substrate;

first means for reflecting light operable in response to the conducting means, wherein the first reflecting means comprise a movable mirror;

second means for reflecting at least a portion of the light incident upon said second reflecting means, said second reflecting means are substantially parallel to said first reflecting means, wherein said second reflecting means comprise an optical stack formed over a substrate; and

means for suspending said first reflecting means, wherein a portion of the suspending means is spaced apart from a portion of the first reflecting means by a gap.

28. The light modulator of claim 27, wherein the suspending means comprise a flexible layer in contact with the first reflecting means.

29. The light modulator of claim 28, wherein the suspending means additionally comprise a plurality of support posts.