Frontside deep trench isolation (fdti) structure for cmos image sensor

Abstract

In some embodiments, the present disclosure relates to a method for forming an image sensor and associated device structure. A FDTI trench is formed from a frontside of a substrate between a first pixel region and a second pixel region and then filled to form a FDTI structure. A cap layer is formed over the FDTI structure overlying the first pixel region and the second pixel region of the substrate. A first photodiode is formed in the first pixel region and a second photodiode is formed in the second pixel region. A FD node is formed within the cap layer between the first pixel region and the second pixel region overlying the FDTI structure. The FD node may be shared by a group of pixel regions not separated by the FDTI structure, such that few metal contacts are needed and thus reduce parasitic capacitance issues of proximity metal contacts.