Image sensor including dual isolation and method of making the same
First Claim
Patent Images
1. A method comprising:
- providing a mask over a substrate, wherein the substrate has a pixel area and a periphery area;
patterning a first opening in the pixel area and a second opening in the periphery area;
etching the mask via the first opening and the second opening;
protecting an entirety of the periphery area;
etching the substrate via the first opening to form a first STI structure having a first depth;
protecting the pixel area;
etching the substrate via the second opening to form a second STI structure having a second depth deeper than the first depth;
depositing an oxide layer in the first and the second STI structures;
removing the mask and an entirety of the oxide layer located above a top surface of the substrate, wherein after removal a surface of the oxide layer is coplanar with the top surface of the substrate;
forming at least one photo detector comprising one or more first NMOS devices in the pixel area, with the proviso that the pixel area does not contain any PMOS devices; and
forming second NMOS devices and PMOS devices in the periphery area.
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Abstract
An image sensor includes a substrate having a pixel region and a periphery region. The image sensor further includes a first isolation structure formed in the pixel region; the first isolation structure including a first trench having a first depth. The image sensor further includes a second isolation structure formed in the periphery region; the second isolation structure including a second trench having a second depth. The second depth is greater than the first depth.
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Citations
20 Claims
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1. A method comprising:
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providing a mask over a substrate, wherein the substrate has a pixel area and a periphery area; patterning a first opening in the pixel area and a second opening in the periphery area; etching the mask via the first opening and the second opening; protecting an entirety of the periphery area; etching the substrate via the first opening to form a first STI structure having a first depth; protecting the pixel area; etching the substrate via the second opening to form a second STI structure having a second depth deeper than the first depth; depositing an oxide layer in the first and the second STI structures; removing the mask and an entirety of the oxide layer located above a top surface of the substrate, wherein after removal a surface of the oxide layer is coplanar with the top surface of the substrate; forming at least one photo detector comprising one or more first NMOS devices in the pixel area, with the proviso that the pixel area does not contain any PMOS devices; and forming second NMOS devices and PMOS devices in the periphery area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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patterning a first photo resist layer over a mask to expose a first portion of a substrate, wherein the first portion is in a pixel array region of the substrate; etching the mask and the first portion of the substrate using the first photo resist layer as a lithography mask to form a first opening having a first depth in the first portion of the substrate; protecting the first portion of the substrate using a second photo resist layer, wherein the second photo resist layer exposes a second portion of the substrate, the second portion is in a peripheral region of the substrate, the second portion is protected during the etching of the first portion; etching the mask and the second portion of the substrate to form a second opening having a second depth in the second portion of the substrate, wherein the second depth is greater than the first depth; filling the first opening and the second opening with an insulating material; forming at least one photo detector in the pixel array region, wherein the forming of the at least one photo detector comprises forming one or more first NMOS devices in the pixel array region with the proviso that the pixel array region does not contain any PMOS devices; and forming second NMOS devices and PMOS devices in the peripheral region. - View Dependent Claims (10, 11)
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12. A method comprising:
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providing a mask over a substrate, wherein the substrate has a pixel area and a periphery area; depositing a photo resist layer over the mask; patterning the photo resist layer to form an opening therein; etching the mask and the substrate via the opening using the photo resist layer as a lithography mask to form a first STI structure having a first depth in the pixel area, wherein the periphery area is protected during the etching of the mask and the substrate; protecting the pixel area; etching the mask and the substrate to form a second STI structure in the periphery area, the second STI structure having a second depth deeper than the first depth; forming at least one photo detector comprising one or more first NMOS devices in the pixel area, with the proviso that the pixel area does not contain any PMOS devices; and forming second NMOS devices and PMOS devices in the periphery area. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification