Provided is a manufacturing method of a semiconductor device wherein the generation of voids is prevented in aluminum-based electrodes or the like. The method is suitable for manufacturing a semiconductor device adapted for vehicles, which is required to have a high reliability. However, it is very difficult that power semiconductor devices such as power MOSFETs, in particular, trench gate type power MOS devices are formed without having any void since the thickness of aluminum-based electrodes thereof is as large as about 3500 to 5500 nm (2.5 μm or more). In the present invention, a method is provided wherein at the time of forming an aluminum-based electrode metal film positioned over a wafer and having a thickness of 2.5 μm or more over a highland/lowland-repeated region in a line and space form by sputtering, the temperature of the wafer is set to 400° C. or higher and lower than 500° C.