Light guide array for an image sensor
An image sensor pixel that includes a photoelectric conversion unit supported by a substrate and an insulator adjacent to the substrate. The pixel includes a light guide that is located within an opening of the insulator and extends above the insulator such that a portion of the light guide has an air interface. The air interface improves the internal reflection of the light guide. Additionally, the light guide and an adjacent color filter are constructed with a process that optimizes the upper aperture of the light guide. These characteristics of the light guide eliminate the need for a microlens.
1. A method of forming an image sensor, comprising:
forming a plurality of photoelectric conversion units supported by a substrate;
forming a support film adjacent to the plurality of photoelectric conversion units;
creating a plurality of openings in the support film each adjacent to a different one of the plurality of photoelectric conversion units and each being separated laterally from another one of the plurality of openings by a support wall, each of the plurality of openings being made wider than a corresponding mask opening to reduce a lateral thickness of the support wall; and,
forming a color filter in each of the plurality of openings.
2. The method of claim 1 , further comprising:
removing at least a portion of the support wall.
3. The method of claim 1 , wherein each of the plurality of openings is made wider than a corresponding mask opening by an undercutting of mask.
4. The method of claim 1 , further comprising:
forming a light guide in each of the plurality of openings.
5. A method of forming an image sensor, comprising:
forming a plurality of photoelectric conversion units supported by a substrate;
forming a support film adjacent to the plurality of photoelectric conversion units;
creating a plurality of openings in the support film each adjacent to a different one of the plurality of photoelectric conversion units and each being separated laterally from another one of the plurality of openings by a support wall, each of the plurality of openings being made wider than a corresponding mask opening to reduce a lateral thickness of the support wall; and,
forming a light guide in each of the plurality of openings.