Method of forming a device isolation region

摘要

A method of forming a device isolation region includes the steps of: forming a first dielectric film and an oxidation-resistant deposition film successively on a semiconductor substrate; forming a trench groove in the semiconductor substrate by successively processing the oxidation-resistant deposition film, the first dielectric film and the semiconductor substrate by anisotropic etching; forming a second dielectric film to cover at least an inner surface of the trench groove; depositing a third dielectric film in the trench groove so that the thickness of the third dielectric film buried in the trench groove is larger than a depth of the trench groove; planarizing a surface of the third dielectric film and an upper surface of the trench groove; and removing the oxidation-resistant deposition film and the first dielectric film to form the device isolation region, wherein a thermal treatment of the entire substrate is carried out to densify the third dielectric film and to oxidize an interface between the second dielectric film and the semiconductor substrate.