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:
- 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 with a material;
forming at least one antireflective layer over the filled backside trenches;
attaching a temporary carrier wafer to the backside surface and removing the substrate; and
after removing the substrate, further processing the image sensor wafer to form the plurality of image sensors including the pixel arrays for the plurality of image sensors.
1 Assignment
0 Petitions
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.
40 Citations
16 Claims
-
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:
-
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 with a material; forming at least one antireflective layer over the filled backside trenches; attaching a temporary carrier wafer to the backside surface and removing the substrate; and after removing the substrate, further processing the image sensor wafer to form the plurality of image sensors including the pixel arrays for the plurality of image sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
Specification