PURPOSE: To reduce the thickness of a metal mask and, at the same time, to improve the adhesive property of the mask by closely sticking the mask to a substrate by means of a magnetizing member provided on the rear surface of the substrate.

CONSTITUTION: When the switch of an electromagnet 3 is turned on after aligning a metal mask 2, the mask 2 is closely stuck to a semiconductor wafer 1. The wafer 1, mask 2, and electromagnet 3 fixed on a fixing member 4 are put in a BLM film forming device and CCB bumps are formed on the wafer 1. Since the mask 2 is formed of such a ferromagnetic material as the 42-alloy, the mask is closely stuck to the substrate 1 by utilizing the magnetic force of the electromagnet 3. Therefore, the mask 2 does not bloat, but closely adhere to the wafer 1. In addition, since the mask 2 can be formed in a desired thickness, the surface of the formed CCB bumps can be flattened and electrical inspections can be smoothly performed with probes.