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US 7,888,159 B2Granted
Image sensor having curved micro-mirrors over the sensing photodiode and method for fabricating
AssigneeOmniVision Technologies, Inc.
InventorsVincent Venezia, Hsin-chih Tai
Life of this patent
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Abstract
The invention involves the integration of curved micro-mirrors over a photodiode active area (collection area) in a CMOS image sensor (CIS) process. The curved micro-mirrors reflect light that has passed through the collection area back into the photo diode. The curved micro-mirrors are best implemented in a backside illuminated device (BSI).
Claims16
A method comprising:
- fabricating an image sensor up to, but not including, a first metallization layer, wherein the image sensor includes a light sensitive element configured to receive light from a light-incident side of the image sensor;
- fabricating a micro-lens on a pre-metal dielectric layer;
- depositing a metal layer of a reflective material on the micro-lens and pre-metal dielectric layer;
- covering the metal layer with photoresist;
- patterning the photoresist to remove the photoresist from all areas except the surface of the micro-lens, wherein the metal layer is exposed in areas where the photoresist is removed;
- etching the exposed metal layer away to form a micro-mirror, wherein the light sensitive element is disposed between the light incident side of the image sensor and the micro-minor;
- removing remaining photoresist;
- and
- covering the micro-minor with a layer of dielectric material.
6 more elements
A method, comprising:
- fabricating a first layer of an image sensor, wherein the image sensor includes a light sensitive element configured to receive light from a light-incident side of the image sensor;
- fabricating a micro-lens on the first layer of the image sensor;
- depositing a metal layer of reflective material on the micro-lens and on the first layer of the image sensor;
- covering the image sensor with photoresist;
- patterning the photoresist to remove the photoresist from all areas except the micro-lens, wherein the metal layer is exposed in areas where the photoresist is removed;
- etching the exposed metal layer of reflective material away to form a micro-mirror, wherein the light sensitive element is disposed between the light incident side of the image sensor and the micro-minor;
- and
- removing remaining photoresist.
5 more elements
Dependencies are inferred from the claim text.