Mechanical layer and methods of shaping the same

• US 8,547,626 B2
• Filed: 03/25/2010
• Issued: 10/01/2013
• Est. Priority Date: 03/25/2010
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Tao, Yi, Zhong, Fan, Sasagawa, Teruo
• Primary Examiner(s): Sugarman, Scott J
• Assistant Examiner(s): Patel, Vipin
• Application Number:
  US12/731,583
• Publication Number:
  US 20110235155A1
• Time in Patent Office: 1,286 Days
• Field of Search: 359290-296
• 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 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• 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 5/284 of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

A method of shaping a mechanical layer is disclosed. In one embodiment, the method comprises depositing a support layer, a sacrificial layer and a mechanical layer over a substrate, and forming a support post from the support layer. A kink is formed adjacent to the support post in the mechanical layer. The kink comprises a rising edge and a falling edge, and the kink can be configured to control the shaping and curvature of the mechanical layer upon removal of the sacrificial layer.

Claims

1. An electromechanical (EMS) systems device, comprising:

a substrate;

a light-absorbing structure on the substrate;

a movable layer; and

a support structure on the substrate for supporting the movable layer, wherein the support structure is configured to space the movable layer from the substrate to define a collapsible gap,

wherein the movable layer includes a kink adjacent to the support structure, wherein the kink includes a rising portion and a falling portion, wherein the rising portion extends away from the gap and the falling portion extends toward the gap, wherein the kink overlaps the light-absorbing structure, wherein the kink is configured to control curvature of the movable layer in such a way that the curvature changes upon application of a bias voltage.

2. The EMS device of claim 1, wherein the kink is spaced from the support structure by less than about 5 μ

m.

3. The EMS device of claim 2, further comprising a stationary electrode positioned between the substrate and the collapsible gap.

4. The EMS device of claim 3, wherein the stationary electrode is an optical stack.

5. The EMS device of claim 3, wherein the movable layer further comprises a bottom reflective surface facing the gap, and wherein the optical stack and the bottom reflective surface of the movable layer form an interferometric modulator (IMOD).

6. The EMS device of claim 5, further comprising a bias circuit configured to apply the bias voltage, wherein when the bias voltage is applied at least a portion of the movable layer is substantially parallel to the substrate.

7. The EMS device of claim 2, wherein the kink extends away from the substrate.

8. The EMS device of claim 7, wherein the kink divides the movable layer into a first portion and a second portion, wherein the first portion is positioned between the support structure and the rising portion of the kink, and wherein thicknesses of the movable layer along the rising portion, the falling portion, the first portion, and the second portion are substantially equal.

9. The EMS device of claim 8, wherein the rising portion of the kink is spaced from the falling portions of the kink by a width of less than about 5 μ

m.

10. The EMS device of claim 8, wherein the rising portion contacts the first portion at a first juncture and the falling portion contacts the second portion at a second juncture, wherein a line drawn through the first juncture and the second juncture is substantially parallel to the first portion and the second portion when the movable layer is in the relaxed position.

11. The EMS device of claim 2, wherein a first portion of the kink is elongated along a first side of the support structure, the first side being along the perimeter of the support structure.

12. The EMS device of claim 11, further comprising one or more additional kinks, wherein the kink and the one or more additional kinks surround greater than about 25 percent of the perimeter of the support structure.

13. The EMS device of claim 11, wherein the kink comprises a closed shape, wherein a side of the closed shape is substantially parallel to the first side of the support structure in contact with the movable layer.

14. The EMS device of claim 2, wherein the movable layer comprises a first conductive layer, a second conductive layer, and a supporting layer, wherein the supporting layer is positioned between the first and second conductive layers.

15. The EMS device of claim 2, wherein the kink extends toward the substrate.

16. The EMS device of claim 1, further comprising:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

17. The EMS device of claim 16, further comprising:

a driver circuit configured to send at least one signal to said display; and

a controller configured to send at least a portion of said image data to said driver circuit.

18. The EMS device of claim 17, further comprising:

an image source module configured to send said image data to said processor.

19. The EMS device of claim 1 wherein the kink is spaced from the support structure by less than a width of the support structure.

20. The EMS device of claim 1, wherein the light-absorbing structure includes a black mask.

21. An electromechanical systems (EMS) device, comprising:

a substrate means;

a light-absorbing means on the substrate means;

a deformable means having a relaxed and an actuated position; and

a support means for supporting the deformable means and for spacing the deformable means from the substrate by a gap,

wherein the deformable means comprises a shaping means for directing curvature of the deformable means so that the curvature changes upon application of a bias voltage, wherein the shaping means overlaps the light absorbing means.

22. The EMS device of claim 21, wherein the shaping means is spaced from the support means by less than about 5 μ

m.

23. The EMS device of claim 21, wherein the shaping means is spaced from the support means by less than a width of the support means.

24. The EMS device of claim 21, wherein the shaping means is adapted to direct the curvature of the deformable means away from the substrate means when the deformable means is in the relaxed position.

25. The EMS device of claim 21, wherein the shaping means includes an elongated rail extending along a side of the support means, the side being along the perimeter of the support means.

26. The EMS device of claim 25, wherein the shaping means includes a kink extending away from the substrate.

27. The EMS device of claim 21, further comprising a fixed electrode positioned between the substrate means and the collapsible gap and a bias means for applying a bias voltage between the fixed electrode and the deformable means, wherein the shaping means is further configured for ensuring flatness of at least a portion of the deformable means when the bias voltage is applied.

28. The EMS device of claim 21, wherein the light-absorbing means includes a black mask.

29. A method of forming a movable layer in an electromechanical systems (EMS) device, comprising:

providing a substrate;

depositing a light-absorbing structure over at least a portion of the substrate;

depositing a support layer over at least a portion of the substrate;

forming a support post from at least the support layer;

providing a movable layer with a kink adjacent to the support post, wherein the kink comprises a rising edge and a falling edge, and wherein the kink overlaps the light-absorbing structure, wherein the kink is configured to control curvature of the movable layer in such a way that the curvature changes upon application of a bias voltage; and

supporting the movable layer with the support post to define a gap over the substrate.

30. The method of claim 29, further comprising depositing a shaping layer over at least a portion of the substrate to form a protrusion, and further comprising depositing a conformal movable layer over the protrusion so that when the movable layer is deposited, the kink is formed in the movable layer over the protrusion.

31. The method of claim 30, wherein a portion of the shaping layer and a portion of the light-absorbing structure are configured to overlap so as to form the protrusion.

32. The method of claim 31, wherein the protrusion comprises the portion of the light-absorbing structure over the portion of the shaping layer.

33. The method of claim 31, wherein the protrusion comprises the portion of the shaping layer over the portion of the light-absorbing structure.

34. The method of claim 30, further comprising:

depositing a sacrificial layer adjacent to the support layer and over at least a portion of the shaping layer and the light-absorbing structure, wherein the step of depositing the sacrificial layer is performed before depositing the movable layer; and

removing the sacrificial layer.

35. The method of claim 29, wherein the light-absorbing structure includes a black mask.