SEMICONDUCTOR DEVICE MANUFACTURING METHOD AND SEMICONDUCTOR DEVICE

There is provided a method of manufacturing a semiconductor device that is suitable for forming a one-step tapered groove even when a substrate material is a difficult-to-etch material. The method of manufacturing a semiconductor device includes a metal mask forming step, a dry etching step, and a metal mask removing step. The metal mask formation step forms a tapered metal mask having an opening on the back surface of the substrate. The opening exposes a part in the back surface, and an edge portion of the opening has a forward taper to the back surface. The dry etching step forms a tapered groove on the substrate by performing, from an upper side of the tapered metal mask, dry etching on the edge portion of the opening and the substrate exposed from the opening. The metal mask removing step removes the tapered metal mask.