Color filter array alignment mark formation in backside illuminated image sensors
First Claim
1. A method of forming color filter array alignment marks in an image sensor wafer, the image sensor wafer being utilized to form a plurality of image sensors each having a pixel array configured for backside illumination, the image sensor wafer comprising at least a substrate and a sensor layer, the method comprising:
- forming color filter array alignment mark openings in the sensor layer; and
forming a single crystalline silicon epitaxial layer on unetched portions of a frontside surface of the sensor layer while simultaneously formingpolysilicon color filter array alignment marks in respective ones of the etched color filter array alignment mark openings in the sensor layer.
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Abstract
A backside illuminated image sensor includes a sensor layer comprising photosensitive elements of the pixel array, an epitaxial layer formed on a frontside surface of the sensor layer, and a color filter array formed on a backside surface of the sensor layer. The epitaxial layer comprises polysilicon color filter array alignment marks formed in locations corresponding to respective color filter array alignment mark openings in the frontside surface of the sensor layer. The color filter array is aligned to the color filter array alignment marks of the epitaxial layer. The image sensor may be implemented in a digital camera or other type of digital imaging device.
26 Citations
10 Claims
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1. A method of forming color filter array alignment marks in an image sensor wafer, the image sensor wafer being utilized to form a plurality of image sensors each having a pixel array configured for backside illumination, the image sensor wafer comprising at least a substrate and a sensor layer, the method comprising:
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forming color filter array alignment mark openings in the sensor layer; and forming a single crystalline silicon epitaxial layer on unetched portions of a frontside surface of the sensor layer while simultaneously forming polysilicon color filter array alignment marks in respective ones of the etched color filter array alignment mark openings in the sensor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification