Light guide array for an image sensor

Abstract

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 cascaded light guide located within an opening of the insulator. The cascaded light guide may include a color filter having an air gap between adjacent color filters that is sealed from above by a transparent sealing film having a concave surface over the air gap to diverge light crossing into the air gap from the concave surface into adjacent color filters. A portion of a support wall between a pair of color filters may have a larger width above than below to form a necking to hold down the color filters for better retention.

1 . An image sensor, comprising:
 a substrate;   a pair of photoelectric conversion units supported by the substrate;   a pair of color filters disposed above the substrate to transmit light to the pair of photoelectric conversion units, the pair being arranged side-by-side with a gap between them, the gap sharing a solid-to-solid interface with each color filter of the pair,   wherein the interface leans towards said each color filter.   
     
     
         2 . The image sensor of  claim 1 , wherein the gap comprises a gaseous medium. 
     
     
         3 . The image sensor of  claim 1 , wherein said each color filter is being pressed down at the solid-to-solid interface. 
     
     
         4 . An image sensor, comprising:
 a substrate;   a photoelectric conversion unit supported by the substrate;   a color filter disposed above the substrate to transmit light to the photoelectric conversion unit, there being a gap between the color filter and an adjacent color filter on one side of the color filter and another gap between the color filter and another adjacent color filter on another side of the color filter, the gap sharing a solid-to-solid interface with the color filter, the other gap also sharing a solid-to-solid interface with the color filter,   wherein both solid-to-solid interfaces lean towards the color filter.   
     
     
         5 . The image sensor of  claim 4 , wherein both gaps comprise a gaseous medium. 
     
     
         6 . The image sensor of  claim 4 , wherein the color filter is being pressed down at the solid-to-solid interfaces. 
     
     
         7 . A method to form an image sensor, comprising:
 providing a substrate;   forming a support film over the substrate;   forming a plurality of openings in the substrate, each opening being wider at a deeper depth than at a shallower depth; and   forming color filters in the plurality of openings.   
     
     
         8 . The method of  claim 7 , further comprising:
 removing at least a portion of the support film between adjacent color filters.   
     
     
         9 . The method of  claim 8 , further comprising:
 forming a solid film in a gap left after said removing to contact the adjacent color filters.   
     
     
         10 . The method of  claim 9 , wherein the solid film extends at least between said deeper depth and said shallower depth.