Patent ID: 7833817

Claim:
A method for fabricating an image sensor, comprising: providing a substrate having a plurality of semiconductor devices formed thereon; forming a plurality of interlayer insulating films and a plurality of interlayer conductive films on the substrate alternately, wherein the interlayer conductive films are electrically connected to the semiconductor devices; forming a plurality of isolated photo-diodes on the topmost layer of the interlayer conductive films, wherein a bottom amorphous silicon layer of the isolated photo-diodes are electrically connected to the topmost layer of the interlayer conductive films; forming a top insulating layer on the topmost layer of the interlayer conductive films, wherein the isolated photo-diodes are covered by the top insulating layer; and forming a top conductive layer in the top insulating layer, wherein the top conductive layer is electrically connected to a top amorphous silicon layer of the isolated photo-diodes, and the step of forming the top insulating layer comprises: performing a low temperature rapid thermal process or atomic layer chemical vapor deposition to form a high quality silicon oxide layer on a surface and sidewall of the isolated photo-diodes; forming a planarization layer to cover the high quality silicon oxide layer and fill a space between the isolated photo-diodes; performing a chemical-mechanical-polish (CMP) process to planarize the planarization layer; forming a plurality of trenches and a plurality of dual damascene contact openings in the high quality silicon oxide layer and the planarization layer, wherein periphery of the top amorphous silicon layer of each isolated photo-diode is exposed by the trenches and the topmost layer of the interlayer conductive films are exposed by the dual damascene contact openings.