A semiconductor manufacturing device has a conveyor configured to convey a tray having an unshielded semiconductor device mounted thereon to go through electromagnetic shielding, and a controller configured to control the conveyor. The controller performs control to take out the tray from a tray supply storage storing trays each having an unshielded semiconductor device mounted thereon to go through the electromagnetic shielding, place the tray on a carrier, and convey this carrier to a sputtering device which coats the unshielded semiconductor device with a sputtering material for the electromagnetic shielding, and the controller performs control to take out, from the sputtering device, the carrier having the tray placed thereon with an electromagnetically shielded semiconductor device being mounted on the tray, convey the tray, pick up the tray having the electromagnetically shielded semiconductor device mounted thereon from the carrier, and store the tray in the tray supply storage.