MANUFACTURING METHOD OF SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To improve the processing accuracy and speed of via hole formation in a semiconductor device equipped with a substrate made of SiC.SOLUTION: A manufacturing method of a semiconductor device 100 provided with a GaN layer 12 on a substrate 10 made of SiC and a via receiving pad 14 on the GaN layer 12 comprises: a step of forming a first via hole 22 penetrating the substrate 10 by performing etching from the lower side of the substrate 10 using fluorine-based gas as etching gas and the GaN layer 12 as a stopper layer, and a step of forming a second via hole 24 penetrating the GaN layer 12 by performing etching from the lower side of the GaN layer 12 using chlorine-based gas that is an etchant different from the formation of the first via hole 22 and the via receiving pad 14 as the stopper layer.