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US 2010/0140729 A1Published application
Lateral overflow drain and channel stop regions in image sensors
AssigneeTruesense Imaging, Inc.
InventorsEdmund K. Banghart, Eric G. Stevens, Hung Q. Doan
Life of this patent
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Abstract
A lateral overflow drain and a channel stop are fabricated using a double mask process. Each lateral overflow drain is formed within a respective channel stop. Due to the use of two mask layers, one edge of each lateral overflow drain is aligned, or substantially aligned, with an edge of a respective channel stop.
Claims5
A method of fabricating one or more lateral overflow drains in an image sensor, the method comprising:
- forming a hard mask layer over an insulating layer, wherein the insulating layer is disposed on a layer having a first conductivity type;
- patterning the hard mask layer to create one or more first openings where channel stops will be formed;
- forming a second mask layer over the hard mask layer and the one or more first openings;
- patterning the second mask layer to create one or more second openings where the one or more lateral overflow drains will be formed, wherein each second opening is disposed in a portion of a respective first opening and a portion of the second mask layer is disposed in the remaining portion of each first opening;
- implanting one or more dopants of a second conductivity type opposite the first conductivity type through the one or more second openings and into the layer having the first conductivity type to form the one or more lateral overflow drains in the layer;
- removing the second mask layer;
- and
- implanting one or more dopants of the first conductivity type through the one or more first openings and into each lateral overflow drain and adjoining layer having the first conductivity type to form the one or more channel stops.
5 more elements
An image sensor comprising,
- a lateral overflow drain formed within a channel stop disposed in a layer, wherein an edge of the lateral overflow drain is aligned with an edge of the channel stop;
- and
- a field oxide region disposed on the channel stop and lateral overflow drain.
Dependencies are inferred from the claim text.