公开(公告)号：US11882697B2

公开(公告)日：2024-01-23

申请号：US17697380

申请日：2022-03-17

Applicant: RENESAS ELECTRONICS CORPORATION

Inventor： Shu Shimizu

IPC: H01L29/788 ,  H01L27/06 ,  H01L21/70 ,  H10B41/42 ,  H01L29/66

CPC classification number: H10B41/42 ,  H01L29/66825 ,  H01L29/7883

Abstract: A non-volatile semiconductor memory and three or more types of transistors are provided. A thickness of a first gate oxide film of a first transistor is larger than that of a second gate oxide film of a second transistor, and is smaller than that of a third gate oxide film of a third transistor. In a first transistor region, a first silicon oxide film is formed on a surface of a semiconductor substrate, and second and third silicon oxide films are formed on the first silicon oxide film. By removing the second and third silicon oxide films and a part of an upper layer of the first silicon oxide film, the first gate oxide film is formed from the first silicon oxide film.