BACKSIDE ILLUMINATED IMAGE SENSOR WITH SHALLOW BACKSIDE TRENCH FOR PHOTODIODE ISOLATION
First Claim
1. A wafer level processing method for forming a plurality of image sensors each having a pixel array configured for backside illumination, the image sensors being formed utilizing an image sensor wafer, the image sensor wafer comprising a substrate and a sensor layer formed over the substrate, the method comprising the steps of:
- forming backside trenches in a backside surface of the sensor layer;
implanting a dopant into the sensor layer through the backside trenches so as to form backside field isolation implant regions corresponding to the backside trenches;
filling the backside trenches;
forming at least one antireflective layer over the filled backside trenches; and
further processing the image sensor wafer to form the plurality of image sensors.
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Accused Products
Abstract
A backside illuminated image sensor comprises a sensor layer implementing a plurality of photosensitive elements of a pixel array, an oxide layer adjacent a backside surface of the sensor layer, and at least one dielectric layer adjacent a frontside surface of the sensor layer. The sensor layer further comprises a plurality of backside trenches formed in the backside surface of the sensor layer and arranged to provide isolation between respective pairs of the photosensitive elements. The backside trenches have corresponding backside field isolation implant regions formed in the sensor layer, and the resulting structure provides reductions in carrier recombination and crosstalk between adjacent photosensitive elements. The image sensor may be implemented in a digital camera or other type of digital imaging device.
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Citations
20 Claims
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1. A wafer level processing method for forming a plurality of image sensors each having a pixel array configured for backside illumination, the image sensors being formed utilizing an image sensor wafer, the image sensor wafer comprising a substrate and a sensor layer formed over the substrate, the method comprising the steps of:
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forming backside trenches in a backside surface of the sensor layer; implanting a dopant into the sensor layer through the backside trenches so as to form backside field isolation implant regions corresponding to the backside trenches; filling the backside trenches; forming at least one antireflective layer over the filled backside trenches; and further processing the image sensor wafer to form the plurality of image sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An image sensor having a pixel array configured for backside illumination, comprising:
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a sensor layer comprising a plurality of photosensitive elements of the pixel array; an oxide layer adjacent a backside surface of the sensor layer; and at least one dielectric layer adjacent a frontside surface of the sensor layer; wherein the sensor layer comprises a plurality of backside trenches formed in the backside surface of the sensor layer and arranged to provide isolation between respective pairs of the photosensitive elements, said backside trenches having corresponding backside field isolation implant regions formed in the sensor layer. - View Dependent Claims (15, 16, 17, 18)
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19. A digital imaging device comprising:
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an image sensor having a pixel array configured for backside illumination; and one or more processing elements configured to process outputs of the image sensor to generate a digital image; wherein said image sensor comprises; a sensor layer comprising a plurality of photosensitive elements of the pixel array; an oxide layer adjacent a backside surface of the sensor layer; and at least one dielectric layer adjacent a frontside surface of the sensor layer; wherein the sensor layer comprises a plurality of backside trenches formed in the backside surface of the sensor layer and arranged to provide isolation between respective pairs of the photosensitive elements, said backside trenches having corresponding backside field isolation implant regions formed in the sensor layer. - View Dependent Claims (20)
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Specification