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US 6,638,786 B2Granted
Image sensor having large micro-lenses at the peripheral regions
AssigneeHua Wei Semiconductor (Shanghai) Co., Ltd.
InventorKatsumi Yamamoto
Life of this patent
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Abstract
An image sensor includes an array of pixels formed in a semiconductor substrate. The pixels are grouped as a center portion of pixels and an outer portion of pixels. A first set of micro-lenses is formed over each of the pixels in the center portion of pixels. A second set of micro-lenses is formed over each of the pixels in the outer portion of pixels. The second set of micro-lenses differ from said first set of micro-lenses. In one embodiment, the second set of micro-lenses are taller than the first set of micro-lenses.
Claims6
A method for forming an image sensor comprising:
- forming a plurality of pixels in a semiconductor substrate, each pixel including a light sensitive element, said pixels grouped as a center portion of pixels and an outer portion of pixels;
- forming a micro-lens material over said plurality of pixels, wherein said micro-lens material is a photoresist;
- exposing said micro-lens material with a first reticle mask to generate gap sections in said micro-lens material;
- exposing said micro-lens material with a second reticle mask to generate top portions in said micro-lens material located in said center portion of pixels;
- developing said micro-lens material to remove said top portions and said gap sections;
- reflowing said micro-lens material to form a first set of micro-lenses over each of said pixels in said center portion of pixels and a second set of micro-lenses over each of said pixels in said outer portion of said pixels,
- wherein said second set of micro-lenses differ from said first set of micro-lenses.
4 more elements
Dependencies are inferred from the claim text.