Patent ID: 8164126

Claim:
An image sensor having a backside illumination structure, comprising: a photo diode unit in a first wafer, the photo diode unit comprising photo diodes and transfer gate transistors coupled to respective ones of the photo diodes, and the photo diode unit configured to be positioned in an incident light path; a wiring line unit on a second wafer, a side of the second wafer that faces upstream in the incident light path bonded to a downstream-facing side of the photo diode unit, the wiring line unit comprising wiring lines and transistors configured to process signals provided by the photo diode unit and configured to control the photo diode unit, and the second wafer positioned between the transistors in the wiring line unit and the photo diodes; a supporting substrate bonded to a downstream-facing side of the wiring line unit; and a filter unit upstream in the incident light path from the first wafer such that the photo diode unit is between the filter unit and the wiring line unit.