Image sensor with pad structure
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsYun-Wei Cheng, Chun-Hao Chou, Kuo-Cheng Lee, Hsun-Ying Huang, Yin-Chieh Huang
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Abstract
The present disclosure relates to an image sensor with a pad structure formed during a front-end-of-line process. The pad structure can be formed prior to formation of back side deep trench isolation structures and metal grid structures. An opening is formed on a back side of the image sensor device to expose the embedded pad structure and to form electrical connections.
Claims20
A method of forming a semiconductor image sensor device, the method comprising:
- forming a plurality of photo detectors in a semiconductor layer, wherein the plurality of photo detectors are configured to detect light that enters into the semiconductor layer through a first surface of the semiconductor layer;
- etching the semiconductor layer to form a first opening in a second surface of the semiconductor layer, wherein the second surface is opposite to the first surface;
- forming, in the first opening, a pad structure that comprises a metal fill;
- disposing interconnect structures on the second surface of the semiconductor layer;
- and
- etching the semiconductor layer to form a second opening in the semiconductor layer to expose at least a portion of the pad structure.
A method of forming a semiconductor image sensor device, the method comprising:
- forming a plurality of photo detectors in a semiconductor layer;
- etching the semiconductor layer to form a first opening in a surface of the semiconductor layer and adjacent to at least one pixel of the plurality of photo detectors;
- forming, in the first opening, a pad structure that comprises a liner layer and a metal fill;
- forming a plurality of isolation structures in the semiconductor layer;
- forming metal grid structures on the plurality of isolation structures;
- and
- etching the semiconductor layer to form a second opening in the semiconductor layer to expose at least a portion of the pad structure.
A semiconductor image sensor device comprising:
- a semiconductor layer having a first surface and a second surface that is opposite the first surface;
- an interconnect structure disposed over the first surface of the semiconductor layer;
- a plurality of radiation-sensing regions formed in the semiconductor layer, wherein the plurality of radiation-sensing regions are configured to sense radiation that enters the semiconductor layer from the second surface;
- a plurality of back side deep trench isolation (BDTI) structures formed in the semiconductor layer;
- and
- a pad structure formed in the semiconductor layer, wherein the pad structure has a depth less than a thickness of the semiconductor layer.
Dependencies are inferred from the claim text.