There is provided a semiconductor device manufacturing method which comprises a step of forming titanium silicide layers (conductive patterns) on a silicon substrate (semiconductor substrate), a step of forming a cover insulating film (underlying insulating film), a step of forming a laminated film containing an alumina film (metal oxide film) on the cover insulating film, a first etching step of forming first holes in the laminated film by etching the laminated film, a cleaning step of cleaning the first holes, and a second etching step of forming second holes in the cover insulating film by etching the cover insulating film via the first holes under second etching conditions after the cleaning step.