Backside structure and method for BSI image sensors

摘要

BSI image sensors and methods. In an embodiment, a substrate is provided having a sensor array and a periphery region and having a front side and a back side surface; a bottom anti-reflective coating (BARC) is formed over the back side to a first thickness, over the sensor array region and the periphery region; forming a first dielectric layer over the BARC; a metal shield is formed; selectively removing the metal shield from over the sensor array region; selectively removing the first dielectric layer from over the sensor array region, wherein a portion of the first thickness of the BARC is also removed and a remainder of the first thickness of the BARC remains during the process of selectively removing the first dielectric layer; forming a second dielectric layer over the remainder of the BARC and over the metal shield; and forming a passivation layer over the second dielectric layer.

主权项

1. A method of forming an image sensor, the method comprising:
receiving a substrate having a sensor array region and a periphery region, the substrate having a front side surface and a back side surface; forming a plurality of metallization layers overlying the front side surface of the substrate; forming a bottom anti-reflective coating (BARC) layer over the back side surface of the substrate, the BARC layer having a first thickness over the sensor array region and a second thickness over the periphery region, the second thickness being greater than the first thickness; forming a metal shield over the second thickness of the BARC layer; and forming one or more dielectric layers over the metal shield and the first thickness of the BARC layer.