Method for forming light pipe structure with high quantum efficiency

• Main Authors: Chou, Shih-Pei, Tsao, Tsun-Kai, Wang, Tzu-Ming, Lu, Jiech-Fun
• Format: Patent
• Language: English
• Published: 26.09.2023
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

Various embodiments of the present disclosure are directed towards a method for forming an image sensor. The method includes forming a photodetector in a substrate. A lower interconnect portion of an interconnect structure is formed over the photodetector. A removal process is performed to define a first opening overlying the photodetector in the lower interconnect portion. A lower etch stop layer is formed lining the first opening. The lower etch stop layer has a U-shape in the first opening. An upper interconnect portion of the interconnect structure is formed over the lower etch stop layer. A light pipe structure is formed overlying the photodetector. The U-shape of the lower etch stop layer extends continuously along sidewalls and a bottom surface of the light pipe structure.