Pixel via and methods of forming the same

• US 8,963,159 B2
• Filed: 04/04/2011
• Issued: 02/24/2015
• Est. Priority Date: 04/04/2011
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lee, Hojin, Zhong, Fan, Tao, Yi
• Primary Examiner(s): NGUYEN, CUONG QUANG
• Application Number:
  US13/079,487
• Publication Number:
  US 20120248478A1
• Time in Patent Office: 1,422 Days
• Field of Search: 257 57- 60, 257/72, 257/E29.003
• US Class Current: 257/72
• 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 systems, methods and apparatuses for pixel vias. In one aspect, a method of forming an electromechanical device having a plurality of pixels includes depositing an electrically conductive black mask on a substrate at each of four corners of each pixel, depositing a dielectric layer over the black mask, depositing an optical stack including a stationary electrode over the dielectric layer, depositing a mechanical layer over the optical stack, and anchoring the mechanical layer over the optical stack at each corner of each pixel. The method further includes providing a conductive via in a first pixel of the plurality of pixels, the via in the dielectric layer electrically connecting the stationary electrode to the black mask, the via disposed at a corner of the first pixel, offset from where the mechanical layer is anchored over the optical stack in an optically non-active area of the first pixel.

Claims

1. A device, comprising:

an array of pixels, each pixel including;

a substrate;

an electrically conductive black mask disposed on the substrate and masking an optically non-active portion of the pixel at each of four corners of the pixel;

a dielectric layer disposed over the black mask;

an optical stack disposed over the dielectric layer, the optical stack including a stationary electrode; and

a mechanical layer positioned over the optical stack and defining a cavity between the mechanical layer and the optical stack, the mechanical layer movable through the cavity between an actuated position and a relaxed position, the mechanical layer anchored over the optical stack at each corner of the pixel;

wherein the array of pixels includes a first pixel having a conductive via in the dielectric layer electrically connecting the stationary electrode to the black mask, the via disposed at a corner of the first pixel offset from where the mechanical layer is anchored over the optical stack in an optically non-active area of the first pixel.

2. The device of claim 1, wherein the array of pixels further includes a second pixel adjacent the first pixel, wherein the second pixel does not include a conductive via in the dielectric layer for electrically connecting the black mask to the stationary electrode.

3. The device of claim 2, wherein a height of the cavity over the first pixel is greater than a height of the cavity over the second pixel.

4. The device of claim 3, wherein the first pixel is a high gap pixel and the second pixel is a mid gap pixel, and wherein the array of pixels further includes a low gap pixel on a side of the mid gap pixel opposite the high gap pixel, wherein the low gap pixel does not include a conductive via in the dielectric layer for electrically connecting the black mask to the stationary electrode.

5. The device of claim 2, wherein an area of the black mask at the corner of the first pixel where the via is disposed is greater than an area of the black mask at a corner of the second pixel.

6. The device of claim 5, wherein the distance from an edge of the black mask at the corner of the first pixel to where the mechanical layer is anchored over the optical stack at the corner of the first pixel is in the range of about 10 μ

m to about 12 μ

m, and wherein the distance from an edge of the black mask at the corner of the second pixel to where the mechanical layer is anchored over the optical stack at the corner of the second pixel is in the range of about 7 μ

m to about 9 μ

m.

7. The device of claim 1, wherein the via is spaced from where the mechanical layer is anchored over the optical stack by a distance ranging between about 6 μ

m to about 8 μ

m.

8. The device of claim 1, wherein the mechanical layer is anchored over the optical stack using a support post.

9. The device of claim 1, wherein the first pixel includes a conductive via in the dielectric layer at each of the four corners of the first pixel, each via electrically connecting the stationary electrode to the black mask, each via offset from where the mechanical layer is anchored over the optical stack at each corner of the first pixel.

10. The device of claim 1, wherein the black mask includes at least one of an optical absorber layer, a dielectric layer, and a conductive bussing layer.

11. The device of claim 10, wherein the via is an opening in the dielectric layer for electrically connecting the conductive bussing layer of the black mask to the stationary electrode of the optical stack.

12. The device of claim 10, wherein the conductive bussing layer includes an aluminum alloy.

13. The device of claim 10, wherein the stationary electrode includes molybdenum-chromium (MoCr).

14. The device of claim 13, further including a bias circuit configured to apply a bias voltage, wherein when the bias voltage is applied at least a portion of the mechanical layer is substantially parallel to the substrate.

15. The device of claim 1, further comprising:

a display;

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; and

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

17. The device of claim 16, further comprising an image source module configured to send the image data to the processor.

18. A device, comprising:

a plurality of pixels, each pixel including

a substrate;

a means for absorbing light disposed on the substrate and masking an optically non-active portion of the pixel at each of four corners of the pixel;

a dielectric layer disposed over the light absorbing means; and

an optical stack disposed over the dielectric layer, the optical stack including a stationary electrode;

wherein the array of pixels includes a first pixel having a means for electrically connecting in the dielectric layer the stationary electrode to the light absorbing means, the connecting means disposed at a corner of the first pixel, offset from where the mechanical layer is anchored over the optical stack in an optically non-active area of the first pixel.

19. The device of claim 18, wherein the first pixel is a high gap pixel, and wherein the array of pixels further includes a mid gap pixel and a low gap pixel, the mid gap pixel adjacent the high gap pixel and the low gap pixel adjacent the mid gap pixel on a side of the mid gap pixel opposite the high gap pixel, wherein the mid gap and low gap pixels do not include a means for electrically connecting in the dielectric layer the stationary electrode to the light absorbing means.

20. The device of claim 19, wherein an area of the light absorbing means at the corner of the high gap pixel where the connecting means is disposed is greater than an area of the light absorbing means at each corner of the low gap and mid gap pixels.

21. The device of claim 18, wherein the connecting means is spaced from where the mechanical layer is anchored over the optical stack by a distance ranging between about 6 μ

m to about 8 μ

m.

22. The device of claim 18, wherein first pixel includes at each of the four corners of the first pixel a means for electrically connecting in the dielectric layer the stationary electrode to the light absorbing means, each connecting means offset from where the mechanical layer is anchored over the optical stack at each corner of the first pixel.