Patent ID: 9570503
Date: 2017-02-14
CPC Classifications: H01L

Claim:
1. A method of fabricating an image sensor device, comprising: providing a substrate having a front surface and a back surface; forming a plurality of radiation-sensing regions in the substrate, each of the radiation-sensing regions being operable to sense radiation projected toward the radiation-sensing region through the back surface; forming an interconnect structure over the front surface of the substrate; thinning the substrate from the back surface; forming a plurality of anti-reflective features over the back surface of the substrate, each of the anti-reflective features being approximately aligned to one of the radiation-sensing regions, the anti-reflective features being separated by a first material that has a lower refractive index than each of the anti-reflective features; forming a layer of a second material that has a lower refractive index than each of the anti-reflective features over the anti-reflective features; and forming a plurality of lenses on the layer of the second material such that each of the plurality of lenses is disposed directly over a respective anti-reflective feature of the plurality of anti-reflective features and such that each of the plurality of lenses extends horizontally beyond the respective anti-reflective feature, wherein the first material is air, and wherein the air extends uninterrupted between adjacent anti-reflective features of the plurality of anti-reflective features.