Method and apparatus for employing a light shield to modulate pixel color responsivity

• US 6,933,168 B2
• Filed: 03/09/2001
• Issued: 08/23/2005
• Est. Priority Date: 09/26/1997
• Status: Expired due to Term

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Intel Corporation
• Inventors: Clark, Lawrence T., Bawolek, Edward J., Beiley, Mark A.
• Primary Examiner(s): Eckert, George
• Assistant Examiner(s): DIAZ, JOSE R
• Application Number:
  US09/802,464
• Publication Number:
  US 20040012029A1
• Time in Patent Office: 1,628 Days
• Field of Search: 257/434, 257/435, 257/440, 257/443, 257/448, 257/457, 257/459, 257/294, 257/98, 438/48, 438/69, 438/70
• US Class Current: 438/70
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H01L 27/14654 Blooming suppression
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration

Abstract

A method and apparatus for employing a light shield to modulate pixel color responsivity. The improved pixel includes a substrate having a photodiode with a light receiving area. A color filter array material of a first color is disposed above the substrate. The pixel has a first relative responsivity. A light shield is disposed above the substrate to modulate the pixel color responsivity. The light shield forms an aperture whose area is substantially equal to the light receiving area adjusted by a reduction factor. The reduction factor is the result of an arithmetic operation between the first relative responsivity and a second relative responsivity, associated with a second pixel of a second color.

Claims

1. A method comprising:

exposing a plurality of photodiodes formed on a first layer of a substrate of an image sensor to a light source;

modifying a light receiving area of a first photodiode and a second photodiode by the use of one or more light shields formed on at least a different second layer of the sensor substrate, such that, for a given size of light receiving area, a first photodiode is exposed to a greater amount of incident light than a second; and

wherein modifying the light receiving area comprises modifying on the basis of a responsivity of a color assigned to one of the first photodiode and the second photodiode.

2. The method of claim 1, wherein modifying the light receiving area comprises masking a portion of one of the first photodiode and the second photodiode from incident light.

3. A method comprising:

providing an image sensor comprising a plurality of pixels formed on a first layer of a sensor substrate;

modifying a light receiving area of alternate pixels by the use of one or more light shields formed on at least a different second layer of the sensor substrate, such that, for a given size of light receiving area, a first pixel is exposed to a greater amount of incident light than a second pixel;

capturing an incident light; and

wherein modifying the light receiving area comprises modifying on the basis of a responsivity of a color assigned to one of the first pixel and the second pixel.

4. The method of claim 3, wherein modifying the light receiving area comprises masking a portion of one of the first pixel and the second pixel from the incident light.