Patent ID: 9536776
Date: 2017-01-03
CPC Classifications: H01L

Claim:
1. A method of manufacturing a semiconductor device, comprising: (a) forming a trench portion in a main surface of a semiconductor substrate; (b) forming a first insulating film having a silicon oxide film in the trench portion and over the main surface of the semiconductor substrate by chemical vapor deposition; (c) forming a second insulating film having a silicon oxide film over the first insulating film by plasma chemical vapor deposition; and (d) forming a third insulating film having a silicon oxide film over the second insulating film by chemical vapor deposition, wherein in (b), the first insulating film covers a first side surface of the trench portion, wherein in (c), the second insulating film covers the first side surface of the trench portion via the first insulating film, wherein in (d), the third insulating film closes therewith the trench portion while leaving a space in the trench portion, and wherein a step coverage property of the second insulating film is lower than those of the first insulating film and third insulating film.