Image sensor and manufacturing method of image sensor
An image sensor comprises a substrate that comprises a first surface, a second surface facing the first surface, and a plurality of pixel regions disposed along a first direction and a second direction. The sensor comprises a plurality of ground regions that are disposed within a portion of the substrate along a depth direction perpendicular to the first direction and the second direction from the first surface of the substrate. The sensor comprises a deep trench that extends from the first surface of the substrate to the second surface of the substrate. The sensor comprises a shallow trench that extends into the portion of the substrate along the depth direction from the first surface of the substrate and is disposed at an outer edge of at least a portion of the deep trench.
1 . An image sensor comprising:
a substrate comprising:
a first surface;
a second surface facing the first surface; and
a plurality of pixel regions disposed along a first direction and a second direction different from the first direction; and
a plurality of ground regions that are disposed within a portion of the substrate along a depth direction perpendicular to the first direction and the second direction from the first surface of the substrate;
a deep trench that extends from the first surface of the substrate to the second surface of the substrate and defines the plurality of pixel regions within the substrate; and
a shallow trench that extends into the portion of the substrate along the depth direction from the first surface of the substrate and is disposed at an outer edge of at least a portion of the deep trench, the shallow trench having a depth that is less than a depth of the deep trench;
wherein on a plane where the first direction and the second direction intersect, the deep trench and the shallow trench are disposed between two ground regions of the plurality of ground regions disposed along the first direction and the deep trench is disposed between two ground regions of the plurality of ground regions disposed along the second direction.
2 . The image sensor of claim 1 , wherein a first distance between the two ground regions disposed along the first direction is wider than a second distance between the two ground regions disposed along the second direction on the plane where the first direction and the second direction intersect.
3 . The image sensor of claim 2 , further comprising:
a pixel separation structure disposed within the deep trench; and
an element separation film disposed within the shallow trench,
wherein first edges parallel to the second direction of the two ground regions disposed along the first direction contact the element separation film, and wherein second edges parallel to the first direction of the two ground regions disposed along the second direction contact the pixel separation structure.
4 . The image sensor of claim 3 , wherein each second depth of the second edges is greater than each first depth of the first edges along the depth direction.
5 . The image sensor of claim 1 , wherein the plurality of ground regions are disposed at a central portion of a region where the plurality of pixel regions are disposed, the central portion located between each of the plurality of pixel regions.
6 . The image sensor of claim 5 , wherein the plurality of pixel regions include a first pixel and a second pixel adjacent to each other along the first direction and a third pixel and a fourth pixel adjacent to each other along the first direction, and the first pixel and the third pixel are adjacent to each other along the second direction and the second pixel and the fourth pixel are adjacent to each other along the second direction.
7 . The image sensor of claim 6 , wherein the plurality of ground regions include a first ground region disposed at the first pixel, a second ground region disposed at the second pixel, a third ground region disposed at the third pixel, and a fourth ground region disposed at the fourth pixel,
wherein the deep trench and the shallow trench parallel to the second direction are disposed between the first ground region and the second ground region and between the third ground region and the fourth ground region, and the deep trench parallel to the first direction is disposed between the first ground region and the third ground region and between the second ground region and the fourth ground region.
8 . The image sensor of claim 7 , wherein a first distance between the first ground region and the second ground region is wider than a second distance between the first ground region and the third ground region on the plane where the first direction and the second direction intersect.
9 . The image sensor of claim 8 , further comprising:
a pixel separation structure disposed within the deep trench; and
an element separation film disposed within the shallow trench,
wherein first edges parallel to the second direction of the first ground region and the second direction of the second ground region contact the element separation film, and second edges parallel to the first direction of the first ground region and the first direction of the third ground region contact the pixel separation structure.
10 . The image sensor of claim 9 , wherein each second depth of the second edges is greater than each first depth of the first edges along the depth direction.