Range modulated implants for image sensors
AssigneeAptina Imaging Corporation
InventorSatyadev Nagaraja
Life of this patent
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Abstract
Image sensors have photodiodes separated by isolations regions formed from p-well or n-well implants. Isolation regions may be formed that are narrow and deep. Isolation regions may be formed in a multi-step process that selectively places implants at desired depths in a substrate. Complementary photoresist patterns may be used. To form an implant near the surface of a substrate, a photoresist pattern with openings over the desired implant area may be used. Subsequent implantation may use a complementary pattern such that ions pass through photoresist before implanting in desired regions of a substrate.
Claims7
A method of forming an image sensor with implanted regions in an image sensor substrate, comprising:
- implanting ions into the image sensor substrate through a first layer of photoresist;
- and
- implanting ions into the image sensor substrate through a second layer of photoresist, wherein the first and second layers of photoresist have respective patterns and wherein the respective pattern of the second layer of photoresist is substantially complementary to the respective pattern of the first layer of photoresist in that the second layer of photoresist has resist islands that correspond to openings in the first layer of photoresist.
Dependencies are inferred from the claim text.