Manufacturing method of a silicon carbide semiconductor device

A manufacturing method of a silicon carbide semiconductor device, comprising:

• depositing an Al film and an Ni film in that order to form a metal lamination film on a SiC semiconductor substrate;
• patterning the metal lamination film by etching using an induction-coupled plasma obtained by ionizing a mixed gas of SF6, O2, and Ar gases, under conditions that the SF6, O2, and Ar gases are caused to flow at flow rates of 26% to 35%, 7.5% to 8.5%, and 58% to 65% with respect to a total gas flow rate, respectively, wherein the temperature of the silicon carbide semiconductor substrate is 30° C.±5° C. and pressure is kept at 3 Pa or more during the patterning of the metal lamination film, wherein the etching produces a metal lamination mask in which Ni film portions cover and overhang Al film portions;
• and
• dry etching a mesa groove at least 10 μm deep in the silicon carbide semiconductor substrate using the metal lamination mask.