Image Sensor with Pixel Wiring to Reflect Light

• US 20110163405A1
• Filed: 03/04/2011
• Published: 07/07/2011
• Est. Priority Date: 03/09/2007
• Status: Abandoned Application

• Current Assignee: Hiok-Nam Tay
• Original Assignee: Hiok-Nam Tay
• Inventors: TAY, Hiok Nam
• Application Number:
  US13/040,321
• Publication Number:
  US 20110163405A1
• Time in Patent Office: Days
• US Class Current: 257/448
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14629 Reflectors
• CPC Class Codes: H01L 27/14636 Interconnect structures

Abstract

An image sensor with a plurality of photodiode pixels supported by a substrate. At least one of the photodiode pixels includes a reflective element that prevents light from traveling onto an adjacent photodiode pixel. The reflective element may be a floating contact on a dielectric barrier that insulates the contact from a substrate. The reflective element may be a via that may or may not be an essential part of an electrical connection between two or more integrated devices. The reflective element may be elongated in a horizontal section parallel to the substrate to maximize the reflective surface area and thus longer than standard vias and contacts. The reflective element may be non-rectilinear. The via may be directly above but insulated from a conductor by a dielectric layer thinner than an inter-metal dielectric (IMD) thickness between interconnect layers, and may straddle one or more conductors.

Claims

1. An image sensor that includes a pixel array that has a center area and a corner area, comprising:

a photo-absorption region of a photodiode and in a substrate;

a first conductor that extends over and parallel to the substrate;

a via above said first conductor;

a hanging wire partially under said via and partially overlapping said first conductor below itself,

wherein a layer of dielectric less than half as thick as the first conductor in a vertical direction perpendicular to the substrate separates said hanging wire from said first conductor.

2. The image sensor of claim 1, wherein said layer of dielectric is at most 2,500 Angstroms thick in said vertical direction.

3. The image sensor of claim 1, wherein said via reaches as high above the substrate as a standard via in a periphery circuit of said image sensor.

4. The image sensor of claim 1, wherein said via is elongated in a horizontal direction.

5. The image sensor of claim 1, wherein said via is partially directly above said first conductor.

6. The image sensor of claim 1, wherein said via partially overlaps said hanging wire.

7. The image sensor of claim 1, wherein said via has a non-rectilinear horizontal section.

8. The image sensor of claim 1, wherein said via has an L-shaped horizontal section.

9. The image sensor of claim 1, wherein a relative lateral position between said via to said first conductor differs from said center area and said corner area.

10. The image sensor of claim 1, wherein said via is under a second conductor that also extends over and parallel to the substrate.

11. The image sensor of claim 10, wherein said via is partially under said second conductor.

12. The image sensor of claim 10, wherein a relative lateral position between said via to one of said first and second conductors differs from said center area and said corner area.