Patent ID: 9564468
Date: 2017-02-07
CPC Classifications: H01L

Claim:
1. A semiconductor structure for back side illumination (BSI) pixel sensors, the semiconductor structure comprising: a plurality of photodiodes arranged within a semiconductor substrate; a metal grid overlying the semiconductor substrate and made up of a plurality of metal grid segments that surround outer perimeters of the plurality of photodiodes, respectively, such that a plurality of first openings within the metal grid overlie the plurality of photodiodes, respectively; a low refractive index (low-n) grid made up of a plurality of low-n grid segments that surround the outer perimeters of the plurality of photodiodes, respectively, such that a plurality of second openings within the low-n grid overlie the plurality of photodiodes, respectively; color filters arranged in the first and second openings and having a refractive index greater than a refractive index of the low-n grid; and a substrate isolation grid extending into the semiconductor substrate and made up of a plurality of isolation grid segments that surround the outer perimeters of the plurality of photodiodes, respectively, wherein the substrate isolation grid is a metal or a low-n material having a refractive index less than a refractive index of the color filters.