Slater and Matsil, L.L.P.
Multiple metal film stack in BSI chips
A method includes forming an opening extending from a back surface of a semiconductor substrate to a metal pad on a front side of the semiconductor substrate, and forming a first conductive layer including a first portion overlapping active image sensors in the semiconductor substrate, a second portion overlapping black reference image sensors in the semiconductor substrate, and a third portion in the opening to contact the metal pad. A second conductive layer is formed over and contacting the first conductive layer. A first patterning step is performed to remove the first and the second portions of the second conductive layer, wherein the first conductive layer is used as an etch stop layer. A second patterning step is performed to remove a portion of the first portion of the first conductive layer. The second and the third portions of the first conductive layer remain after the second patterning step.
Taiwan Semiconductor Manufacturing Company, Ltd.
H H H H
H01L H01L H01L H01L
inventional additional inventional inventional
Yeur-Luen Ching-Chun Shyh-Fann Ming-I Jiech-Fun
Tu Wang Ting Wang Lu