公开(公告)号：US11164946B2

公开(公告)日：2021-11-02

申请号：US16461721

申请日：2017-12-14

Applicant: CSMC TECHNOLOGIES FAB2 CO., LTD.

Inventor： Tao Liu ,  Zhibin Liang ,  Song Zhang ,  Yan Jin ,  Dejin Wang

IPC: H01L29/423 ,  H01L21/28 ,  H01L29/66 ,  H01L27/11517 ,  H01L29/788

Abstract: A manufacturing method for a flash device. A manufacturing method for a flash device, comprising: providing a substrate; forming sequentially, on the substrate, a floating gate (FG) oxide layer, an FG polycrystalline layer, and an FG mask layer; etching, at the FG location region, the FG polycrystalline layer and the FG mask layer, forming a window on the FG mask layer, and forming a trench on the FG polycrystalline layer, the window being communicated with the trench; performing second etching of the side wall of the window of the FG mask layer, enabling the width of the trench located on the FG polycrystalline layer to be less than the width of the secondarily-etched window located on the FG mask layer; and oxidizing the FG polycrystalline layer, enabling the oxide to fill the trench to form a field oxide layer; and etching an FG having sharp angles.