Grounding System for Integrated Circuits of Particular Usefulness for Circuits Incorporating Backside-Illuminated Photosensor Arrays

摘要

A backside-illuminated photosensor array IC is formed in a thinned circuit wafer. Silicon is removed in at least one substrate-stripped zone where a doped edge-contact ring surrounds the substrate-stripped zone, the edge-contact ring formed in a same first side of the wafer as a plurality of transistors, and opposite to a backside of the wafer. Backside metal is disposed on the backside of the wafer, the backside metal having window openings over the photosensors, and having sidewalls contacting the edge-contact ring around the substrate-stripped zone. The edge contact region is formed in the first side of the device wafer before providing structural support and thinning the device wafer. Substrate-stripped zones, such as bondpad openings and guardring openings, are formed by removing silicon to expose the edge-contact region, and backside metal is deposited with sidewall metal at edges of the substrate-stripped zones and thereby contacting the edge-contact region.

主权项

1. A photosensor array integrated circuit configured for backside illumination comprising:
a thinned circuit Silicon wafer substrate having formed within it an array of photosensors and transistors, the wafer having silicon removed in at least one substrate-stripped zone; a doped edge-contact region adjacent to the at least one substrate-stripped zone, and formed in a same side of the wafer as a plurality of transistors, a side of the wafer in which the transistors are formed being an opposite side to a backside of the wafer; and backside metal disposed over the backside of the wafer, the backside metal having window openings over the photosensors, and having sidewalls extending into the substrate-stripped zone and contacting the edge-contact region adjacent to the substrate-stripped zone.