Taiwan Semiconductor Manufacturing Comp. Ltd.

Po-Han Chen

Kuo-Cheng Lee

Fu-Cheng Chang

Chen-Chun Chen

A method of making an image sensor includes depositing a shield layer over a substrate, wherein the substrate comprises a first photodiode (PD) and a second PD. The method further includes etching the shield layer to define a first recess aligned with the first PD and a second recess aligned with the second PD. The method further includes depositing a flicker reduction layer in the first recess and in the second recess. The method further includes etching the flicker reduction layer to remove the flicker reduction layer from the first recess.

Image sensor and method of making

Photosensors may be formed on a front side of a semiconductor substrate. An optical refraction layer having a first refractive index may be formed on a backside of the semiconductor substrate. A grid structure including openings is formed over the optical refraction layer. A masking material layer is formed over the grid structure and the optical refraction layer. The masking material layer may be anisotropically etched using an anisotropic etch process that collaterally etches a material of the optical refraction layer and forms non-planar distal surface portions including random protrusions on physically exposed portions of the optical refraction layer. An optically transparent layer having a second refractive index that is different from the first refractive index may be formed on the non-planar distal surface portions of the optical refraction layer. A refractive interface refracts incident light in random directions, and improves quantum efficiency of the photo sensors.

Backside refraction layer for backside illuminated image sensor and methods of forming the same

An image sensor includes a substrate and a first photodiode (PD) having a first size in the substrate. The image sensor further includes a second PD having a second size in the substrate, wherein the first size is different from the second size. The image sensor further includes a first buffer layer over the substrate. The image sensor further includes a shield layer over the first buffer, wherein the first buffer layer and the shield layer define a first recess aligned with the first PD and a second recess aligned with the second PD. The image sensor further includes a flicker reduction layer in the first recess, wherein the second recess is free of the flicker reduction layer.

Photosensors may be formed on a front side of a semiconductor substrate. An optical refraction layer having a first refractive index may be formed on a backside of the semiconductor substrate. A grid structure including openings is formed over the optical refraction layer. A masking material layer is formed over the grid structure and the optical refraction layer. The masking material layer may be anisotropically etched using an anisotropic etch process that collaterally etches a material of the optical refraction layer and forms non-planar distal surface portions including random protrusions on physically exposed portions of the optical refraction layer. An optically transparent layer having a second refractive index that is different from the first refractive index may be formed on the non-planar distal surface portions of the optical refraction layer. A refractive interface refracts incident light in random directions, and improves quantum efficiency of the photosensors.

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Hsinchu, Taiwan

Po-Han Chen