METHOD OF FORMING FILED REGION OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: The method improves the reliability in the fabrication of a semiconductor device requiring a fine pattern by assuring an active region sufficiently by forming a field oxide(88) easily using a SiON film(84). CONSTITUTION: The method comprises the steps of: forming a pad oxide(82), the SiON film and a silicon nitride film(86) on a semiconductor substrate(80) in sequence; removing the silicon nitride film and the SiON film on some region on the semiconductor substrate in sequence; forming the field oxide with the pad oxide revealed by the removal of the silicon nitride film and the SiON film; and removing the silicon nitride film and the SiON film completely which are remained behind on the semiconductor substrate. The SiON film is formed in the thickness of 260 angstrom or 340 angstrom with PECVD, and the SiON film and the silicon nitride film are removed using a phosphoric acid.