CMOS image sensor with embedded micro-lenses
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsVolume Chien, Zen-Fong Huang, Chia-Yu Wei, Chi-Cherng Jeng, Hsin-Chi Chen
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Abstract
A backside illuminated CMOS image sensor and a manufacturing method thereof are provided. Embedded micro-lenses disposed respectively on concave surfaces of a buffer oxide layer, wherein the concave surfaces are positioned to respectively align with photodiodes of pixel array of the CMOS image sensor. The embedded micro-lenses can confine incident light to the photodiodes to reduce optical crosstalk between adjacent pixels.
Claims17
A backside illuminated CMOS image sensor device, comprising:
- a substrate having a pixel array on a front surface of the substrate;
- a dielectric layer disposed on a back surface of the substrate to cover a backside of the pixel array;
- a buffer oxide layer disposed on the dielectric layer, wherein the buffer oxide layer has a plurality of concave surfaces positioned to respectively align with each photodiode in the pixel array;
- a grid layer disposed on the dielectric layer and having a plurality of openings to respectively expose the concave surfaces of the buffer oxide layer;
- a plurality of embedded micro-lenses respectively disposed on the concave surfaces of the buffer oxide layer;
- and
- a plurality of color filter sheets respectively disposed on each of the embedded micro-lenses, wherein a refractive index of the micro-lenses is smaller than a refractive index of the buffer oxide layer.
A method of manufacturing a backside illuminated CMOS image sensor device, the method comprising:
- forming a dielectric layer on a back surface of a substrate, wherein the substrate has a pixel array formed on a front surface of the substrate;
- forming a buffer oxide layer on the dielectric layer;
- etching the buffer oxide layer to form a plurality of concave surfaces positioned to respectively align with each photodiode in the pixel array;
- forming a plurality of micro-lenses respectively disposed on the concave surfaces of the buffer oxide layer;
- forming a grid layer on the buffer oxide layer and with a plurality of openings exposing each of the micro-lenses;
- and
- forming a plurality of color filter sheets respectively in the openings, wherein a refractive index of the micro-lenses is smaller than a refractive index of the buffer oxide layer, for avoiding total reflection of incident light.
A method of manufacturing a backside illuminated CMOS image sensor device, the method comprising:
- forming a dielectric layer on a back surface of a substrate, wherein the substrate has a pixel array formed on a front surface of the substrate;
- forming a buffer oxide layer on the dielectric layer;
- forming a grid layer on the buffer oxide layer and with a plurality of openings positioned to respectively align with each photodiode in the pixel array and continuously etching the exposed buffer oxide layer to form concave surfaces respectively at the bottoms of the openings;
- forming a plurality of micro-lenses respectively on the concave surfaces of the buffer oxide layer;
- and
- forming a plurality of color filter sheets respectively in the openings of the grid layer, wherein a refractive index of the micro-lenses is smaller than a refractive index of the buffer oxide layer, for avoiding total reflection of incident light.
Dependencies are inferred from the claim text.