Apparatus and method for reducing cross talk in image sensors
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJeng-Shyan Lin, Dun-Nian Yaung, Jen-Cheng Liu, Tzu-Hsuan Hsu, Shuang-Ji Tsai, Min-Feng Kao
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Abstract
A method for reducing cross talk in image sensors comprises providing a backside illuminated image sensor wafer, forming an isolation region in the backside illuminated image sensor wafer, wherein the isolation region encloses a photo active region, forming an opening in the isolation region from a backside of the backside illuminated image sensor wafer and covering an upper terminal of the opening with a dielectric material to form an air gap embedded in the isolation region of the backside illuminated image sensor wafer.
Claims20
An apparatus comprising:
- a substrate having a first side and a second side, wherein the first side is adjacent to a photo active region;
- an isolation region disposed adjacent to the photo active region in the first side of the substrate;
- an air gap embedded in the isolation region, wherein the air gap is encapsulated by a dielectric material, and wherein the air gap is adjacent to the second side of the substrate, and wherein a bottom of the air gap is lower than a bottom of the photo active region with reference to the second side;
- and
- a negative charge layer along sidewalls of the air gap.
A device comprising:
- a substrate with a first conductivity;
- an epitaxial layer formed on the substrate;
- a first photo active region having a second conductivity formed in a first side of the substrate;
- a second photo active region having the first conductivity formed in the first side of the substrate;
- an isolation region, wherein the first photo active region and the second photo active region are enclosed by the isolation region;
- an air gap in the isolation region, wherein a bottom of the air gap is deeper than the first photo active region and the second photo active region with reference to the first side of the substrate;
- and
- an air gap covering layer on an opening of the air gap.
A structure comprising:
- an epitaxial layer over a substrate;
- a photodiode in the epitaxial layer, wherein the photodiode is adjacent to a front side of the epitaxial layer;
- and
- an isolation region surrounding the photodiode, wherein the isolation region comprises an air gap structure, and wherein a bottom of the air gap structure is deeper than the photodiode with reference to the front side.
Dependencies are inferred from the claim text.