公开(公告)号：US20180033677A1

公开(公告)日：2018-02-01

申请号：US15547200

申请日：2015-09-24

Applicant: CSMC TECHNOLOGIES FAB2 CO., LTD.

Inventor： Hua SONG ,  Jiao WANG ,  Huan YANG

IPC: H01L21/762

CPC classification number: H01L21/76202 ,  H01L21/762 ,  H01L21/76205 ,  H01L21/76224 ,  H01L21/76227 ,  H01L21/76264 ,  H01L21/76286 ,  H01L21/763 ,  H01L21/823481

Abstract: A method for preparing a trench isolation structure, which comprises the following steps of: providing a substrate; forming an oxide layer on the substrate; successively generating an oxidation barrier layer and an ethyl orthosilicate layer on the surface of the oxide layer; etching the oxidation barrier layer and the ethyl orthosilicate layer; corroding the substrate to form a trench by using the oxidation barrier layer and the ethyl orthosilicate layer as mask layers; removing the ethyl orthosilicate layer, and oxidizing a side wall of the trench by using the oxidation barrier layer as a barrier layer; filling the trench with a polysilicon and then etching back the polysilicon, and removing the polysilicon on the surface of the oxidation barrier layer; and removing the oxidation barrier layer and the oxide layer on the surface of the substrate.