Mechanical layer and methods of forming the same

• US 8,817,357 B2
• Filed: 04/08/2011
• Issued: 08/26/2014
• Est. Priority Date: 04/09/2010
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Tao, Yi, Zhong, Fan, de Groot, Wilhelmus A.
• Primary Examiner(s): Choi, William
• Assistant Examiner(s): BROOME, SHARRIEF I
• Application Number:
  US13/082,955
• Publication Number:
  US 20110249315A1
• Time in Patent Office: 1,236 Days
• Field of Search: 359/290, 359/291, 359/578, 359/528, 359/529, 359/522
• US Class Current: 359/290
• 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

This disclosure provides mechanical layers and methods of forming the same. In one aspect, an electromechanical systems device includes a substrate and a mechanical layer having an actuated position and a relaxed position. The mechanical layer is spaced from the substrate to define a collapsible gap. The gap is in a collapsed condition when the mechanical layer is in the actuated position and in a non-collapsed condition when the mechanical layer is in the relaxed position. The mechanical layer includes a reflective layer, a conductive layer, and a supporting layer. The supporting layer is positioned between the reflective layer and the conductive layer and is configured to support the mechanical layer.

Claims

1. An electromechanical device, comprising:

a substrate;

a partially reflective optical stack disposed on the substrate;

a movable mechanical layer positioned so that the partially reflective optical stack is between the mechanical layer and the substrate, the mechanical layer including a reflective layer, a conductive layer, and a supporting layer that is disposed between the reflective layer and the conductive layer, wherein the supporting layer is anchored on the optical stack in an optically non-active anchor region and extends from the anchor region away from the optical stack spacing the mechanical layer from the optical stack to define a collapsible gap between the mechanical layer and the optical stack; and

a dielectric layer disposed on the mechanical layer such that the mechanical layer is between the dielectric layer and the collapsible gap,

wherein the mechanical layer is movable to an actuated position and a relaxed position by applying a voltage across the mechanical layer and a stationary electrode disposed between the substrate and the collapsible gap, and wherein the collapsible gap is in a collapsed state when the mechanical layer is in the actuated position and the gap is in a non-collapsed state when the mechanical layer is in the relaxed position, and wherein the mechanical layer further includes a kink disposed adjacent to the anchor region and in at least a portion of an optically non-active region, wherein the kink includes an upwardly extending portion of the mechanical layer configured to control at least one of a height of the collapsible gap and a curvature of the mechanical layer.

2. The device of claim 1, wherein the kink in the mechanical layer includes a rising portion extending away from the gap and a falling portion extending towards the gap.

3. The device of claim 1, wherein the reflective layer and the conductive layer include aluminum alloys.

4. The device of claim 1, wherein the supporting layer includes a dielectric material.

5. The device of claim 4, wherein the supporting layer includes silicon oxynitride (SiON).

6. The device of claim 4, wherein a portion of the supporting layer extends past the reflective layer and towards the optical stack, and wherein the supporting layer contacts the optical stack in the anchor region.

7. The device of claim 1, wherein the supporting layer is between about 500 Å

and about 8000 Å

thick.

8. The device of claim 1, wherein the dielectric layer is between about 500 Å

and about 4000 Å

thick.

9. The device of claim 1, wherein the reflective layer includes an aluminum-copper (AlCu) layer having a thickness of between about 200 Å

and about 500 Å

.

10. The device of claim 9, wherein the conductive layer includes an AlCu layer having a thickness of between about 200 Å

and about 500 Å

.

11. The device of claim 1, wherein a height dimension of the kink is between about 400 Å

and about 5000 Å

.

12. The device of claim 11, where a width dimension of the kink is between about 0.2 μ

m and about 5 μ

m.

13. The device of claim 1, wherein the optical stack includes the stationary electrode.

14. The device of claim 1, wherein the optical stack, the reflective layer of the mechanical layer, and the collapsible gap form an interferometric modulator.

15. The device of claim 1, further comprising:

a display including the substrate, the optical stack, and the mechanical layer;

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

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

16. The device of claim 15, further comprising a driver circuit configured to send at least one signal to the display.

17. The device of claim 16, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

18. The device of claim 15, further comprising an image source module configured to send the image data to the processor.

19. The device of claim 18, wherein the image source module includes at least one of a receiver, transceiver, and transmitter.

20. The device of claim 15, further comprising an input device configured to receive input data and to communicate the input data to the processor.

21. A device, comprising:

a substrate;

means for partially reflecting light, the partially reflecting means disposed on the substrate;

movable means for reflecting light, the movable reflecting means positioned so that the partially reflecting means is between the movable reflecting means and the substrate, the movable reflecting means including a means for supporting the movable reflecting means, the supporting means anchored on the partially reflecting means in an optically non-active anchor region, wherein the supporting means extends from the anchor region away from the partially reflecting means spacing the movable reflecting means from the partially reflecting means to define a collapsible gap between the movable reflecting means and the partially reflecting means; and

a dielectric layer disposed on the movable reflecting means such that the supporting means is between the dielectric layer and the collapsible gap,

wherein the movable reflecting means is movable to an actuated position and a relaxed position by applying a voltage across the movable reflecting means and a stationary electrode disposed between the substrate and the collapsible gap, and wherein the collapsible gap is in a collapsed state when the movable reflecting means is in the actuated position and the gap is in a non-collapsed state when the movable reflecting means is in the relaxed position, wherein the movable reflecting means further includes a kink disposed adjacent to the anchor region and in at least a portion of an optically non-active region, wherein the kink includes an upwardly extending portion of the movable reflecting means configured to control at least one of a height of the collapsible gap and a curvature of the movable reflecting means.

22. The device of claim 21, wherein the partially reflecting means includes an optical stack, and the optical stack includes the stationary electrode.

23. The device of claim 22, wherein the movable reflecting means includes a reflective layer and a conductive layer, wherein the supporting means includes a support layer comprising a dielectric material, and wherein the support layer is disposed between the reflective layer and the conductive layer.

24. The device of claim 23, wherein a portion of the support layer in the anchor region extends past the reflective layer and towards the optical stack, and the optical layer contacts the optical stack in the anchor region.

25. A method of forming a mechanical layer in an electromechanical device, the method comprising:

providing a substrate;

forming an optical stack over the substrate;

providing a sacrificial layer over the optical stack;

removing a portion of the sacrificial layer that is disposed over an anchoring region;

forming a mechanical layer over the sacrificial layer and the anchoring region, wherein forming the mechanical layer includes providing a reflective layer over the sacrificial layer, removing a portion of the reflective layer that is disposed over the anchoring region, providing a supporting layer over the reflective layer such that a portion of the supporting layer contacts the anchoring region, and providing a conductive layer over the supporting layer;

depositing a dielectric layer over the conductive layer;

removing the sacrificial layer to form a collapsible gap between the mechanical layer and the substrate; and

depositing a shaping layer over at least a portion of the substrate adjacent to the anchoring region, the shaping layer including at least one protrusion that extends away from the substrate, wherein the optical stack is formed over the shaping layer, and wherein forming the mechanical layer includes forming the mechanical layer over the at least one protrusion such that a kink is formed in a portion of the mechanical layer over the at least one protrusion, wherein the kink includes an upwardly extending portion of the mechanical layer configured to control at least one of a height of the collapsible gap after removing the sacrificial layer and a curvature of the mechanical layer after removing the sacrificial layer.

26. The method of claim 25, wherein providing the sacrificial layer includes forming the sacrificial layer as a conformal layer over the shaping layer including over the at least one protrusion, and wherein forming the mechanical layer further includes forming the mechanical layer over the sacrificial layer and the shaping layer, including the at least one protrusion, as a conformal layer such that the kink is formed in the portion of the mechanical layer over the at least one protrusion.

27. The method of claim 26, further comprising depositing a black mask over at least a portion of the substrate, wherein a portion of the shaping layer and a portion of the black mask overlap so as to define a height dimension of the protrusion.

28. The method of claim 25, wherein the supporting layer includes a dielectric material.

29. The method of claim 25, wherein the supporting layer directly contacts the optical stack over the anchoring region.

30. The method of claim 25, wherein the supporting layer has a thickness of between about 500 Å

and about 8000 Å

.

31. The method of claim 25, wherein the conductive layer includes an AlCu layer having a thickness of between about 200 Å

and about 500 Å

.

32. The method of claim 25, wherein the dielectric layer has a thickness of between about 500 Å

to about 4000 Å

.

33. The method of claim 25, wherein the shaping layer includes a buffer oxide layer having a thickness of about 500 Å

to about 6000 Å

.

34. The method of claim 27, further comprising depositing an aluminum oxide layer on the substrate before depositing the black mask.

35. The method of claim 34, wherein the aluminum oxide layer has a thickness of between about 50 Å

and about 250 Å

.