Front side implanted guard ring structure for backside
First Claim
1. A method of forming a backside illuminated image sensor, the method comprising:
- forming a guard ring structure of a predetermined depth in a front-side surface of a semiconductor substrate, the guard ring structure outlining a two-dimensional array of pixels, each pixel of the array of pixels separated from an adjacent pixel by the guard ring structure;
forming at least one image sensing element on the front-side surface of the semiconductor substrate, the at least one image sensing element being formed in a pixel of the array of pixels and surrounded by the guard ring structure; and
reducing a thickness of the semiconductor substrate until the guard ring structure is co-planar with a back-side surface of the semiconductor substrate.
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Abstract
A method of forming a backside illuminated image sensor includes forming a guard ring structure of a predetermined depth in a front-side surface of a semiconductor substrate, the guard ring structure outlining a two-dimensional array of pixels, each pixel of the array of pixels separated from an adjacent pixel by the guard ring structure. The method further includes forming at least one image sensing element on the front-side surface of the semiconductor substrate, the at least one image sensing element being formed in a pixel of the array of pixels and surrounded by the guard ring structure. The method further includes reducing a thickness of the semiconductor substrate until the guard ring structure is co-planar with a back-side surface of the semiconductor substrate.
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Citations
20 Claims
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1. A method of forming a backside illuminated image sensor, the method comprising:
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forming a guard ring structure of a predetermined depth in a front-side surface of a semiconductor substrate, the guard ring structure outlining a two-dimensional array of pixels, each pixel of the array of pixels separated from an adjacent pixel by the guard ring structure; forming at least one image sensing element on the front-side surface of the semiconductor substrate, the at least one image sensing element being formed in a pixel of the array of pixels and surrounded by the guard ring structure; and reducing a thickness of the semiconductor substrate until the guard ring structure is co-planar with a back-side surface of the semiconductor substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of forming a backside illuminated image sensor, the method comprising:
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forming a guard ring structure of a predetermined depth in a front-side surface of a semiconductor substrate, the guard ring structure outlining a two-dimensional array of pixels, each pixel of the array of pixels separated from an adjacent pixel by the guard ring structure; forming at least one image sensing element on the front-side surface of the semiconductor substrate, the at least one image sensing element being formed in a pixel of the array of pixels and surrounded by the guard ring structure; determining a thickness difference between a thickness of the semiconductor substrate and the predetermined depth; and reducing a thickness of the semiconductor substrate to remove an entirety of the determined thickness difference.
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12. An image sensor, comprising:
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a semiconductor substrate, the substrate having a front-side surface and a back-side surface opposite the front-side surface; a plurality of image sensing elements formed on the front-side surface of the substrate; and a guard ring structure separating each of the image sensing elements from other image sensing elements, wherein the guard ring structure is co-planar with the back-side surface of the substrate. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification