公开(公告)号：US11862509B2

公开(公告)日：2024-01-02

申请号：US17319368

申请日：2021-05-13

Applicant: OmniVision Technologies, Inc.

Inventor： Seong Yeol Mun ,  Heesoo Kang ,  Xiang Zhang

IPC: H01L27/146 ,  H01L21/762

CPC classification number: H01L21/76224 ,  H01L27/1463 ,  H01L27/14643 ,  H01L27/14689

Abstract: A shallow trench isolation (STI) structure and method of fabrication includes forming a shallow trench isolation (STI) structure having a polygonal shaped cross-section in a semiconductor substrate of an image sensor includes a two-step etching process. The first step is a dry plasma etch that forms a portion of the trench to a first depth. The second step is a wet etch process that completes the trench etching to the desired depth and cures damage caused by the dry etch process. A CMOS image sensor includes a semiconductor substrate having a photodiode region and a pixel transistor region separated by a shallow trench isolation (STI) structure having a polygonal shaped cross-section.