Patent ID: 7838318

Claim:
A method of forming a contact of a three-dimensional multi-layer structure image sensor in which a multi-layer photodiode layer is laminated and a transistor layer is laminated at the highest layer, the method comprising the steps of: forming a photoresist layer for etching on a substrate on which a plurality of photodiode layers and transistor layers are laminated; drilling a trench for pixel isolation to a desired depth; forming an insulating layer on sidewalls of an isolation type trench groove formed by the drilling; performing doping for forming a buried diode within a sidewall insulating layer of the isolation type trench groove; filling the isolation type trench groove with an insulating layer; drilling a trench groove for contact to a desired depth; doping a bottom surface of the contact type trench groove to form a contact becoming conductive to the polarity of an underlying photodiode; and filling the contact type trench groove with a conductor.