To provide a manufacturing method for semiconductor manufacturing device that can suppress the development of striations when forming holes by etching an etch target film composed of an inorganic insulating film, a first sacrifice film stacked on this insulating film and having components different from those of the insulating film, a second sacrifice film formed of an inorganic insulating film, whereon a pattern for forming grooves for wiring embedment on the insulating film is formed. In a substrate including a photoresist film, wherein a pattern for forming holes for embedding the wiring material on the upper layer of the above etch target film, a thickness of the above organic layer is greater than a thickness of an etch target layer composed of the above insulating film, the above first sacrifice film and the above second sacrifice film, a mixed gas containing CF4 gas and CHF3 gas is converted into plasma, and the etch target layer is etched by using the plasma.