Patent ID: 9418887
Filing Date: 2016-08-16
CPC Classification: H01L

Claim Text:
1. A method for manufacturing a semiconductor device, comprising: forming a first insulating film; forming a second insulating film on the first insulating film; forming a third insulating film on the second insulating film; etching the third insulating film to form features extending in a first direction; forming a spacer film on lateral sides of the etched features of the third insulating film; removing the third insulating film; etching the second insulating film not covered by the spacer film to form features extending in the first direction; performing a first etching of the first insulating film to form features extending in the first direction; forming a first mask having features at intervals along the first direction and extending in a second direction, crossing the first direction, on the first and second insulating films; and performing a second etching of the first insulating film using the first mask wherein the first etching removes portions of the first insulating film to a first depth into the first insulating film, the second etching removes portions of the first insulating film to a second depth into the first insulating film that is greater than the first depth, the first etching forms trenches in the first insulating film, the trenches having a bottom surface at the first depth and sidewalls extending along the first direction and spaced from each other in the second direction, the second etching extends the depth of some but not all portions of at least one trench formed by the first etching from the first depth to the second depth, and the second insulating film is used as a mask for patterning the first insulating film.