Abstract: A method for manufacturing a semiconductor device includes forming a mask layer including a) one metal from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, and iridium, b) boron, and c) carbon on a layer to be etched. The mask layer is patterned. A hole or a groove is formed in the layer to be etched by performing dry etching on the layer to be etched using the patterned mask layer. The mask layer includes a first region and a second region. The first region includes boron and the second region includes boron such that a density of boron in the second region is different from a density of boron in the first region, or the first region includes carbon and the second region includes carbon such that a density of carbon in the second region is different from a density of carbon in the first region.