Patent ID: 9502282
Filing Date: 2016-11-22
CPC Classification: G03F,H01L

Claim Text:
1. A method of manufacturing a semiconductor integrated circuit device comprising the steps of: (a) forming a first silicon nitride-based insulating film over a first main surface of a semiconductor wafer; (b) forming a first silicon oxide-based insulating film over the first silicon nitride-based insulating film; (c) forming a second silicon nitride-based insulating film over the first silicon oxide-based insulating film; d) applying a carbon-rich film directly onto the second silicon nitride-based insulating film; (e) applying a silicon-containing film containing carbon and silicon as main components thereof directly onto the carbon-rich film; (f) applying a photoresist film directly onto the silicon-containing film; (g) exposing the photoresist film by reduction projection exposure using an ultraviolet exposure light; (h) after the step (g), developing the photoresist film to pattern the photoresist film and transferring the resulting pattern to the silicon-containing film and the carbon-rich film successively; (i) forming a through-hole in the second silicon nitride-based insulating film by first dry etching with the resulting carbon-rich film as a mask; (j) after the step (i), extending the through-hole to a bottom surface of the first silicon oxide-based insulating film by second dry etching with the carbon-rich film as a mask; (k) after the step (j), removing the carbon-rich film; and (l) after the step (k), removing the second silicon nitride-based insulating film outside the through-hole and the first silicon nitride-based insulating film at a bottom of the through-hole, wherein in the step (g), by an off-axis type oblique incidence autofocus optical system using a reference beam having a wavelength longer than that of the ultraviolet exposure light, the reference beam is made incident obliquely to the first main surface of the semiconductor wafer and based on the reflected light, autofocusing is performed.