A plurality of semiconductor chips (23) are bonded to an adhesive layer (22) formed on a base plate (21). Then, first to third insulating films (31, 35, 39), first and second underlying metal layers (33, 37), first and second re-wirings (34, 38), and a solder ball (41) are collectively formed for the plural semiconductor chips (23). In this case, the first and second underlying metal layers (33, 37) are formed by a sputtering method, and the first and second re-wirings (34, 38) are formed by an electroplating method. Then, a laminate structure consisting of the three insulating films (39, 35, 31), the adhesive layer (22), and the base plate (21) is cut in a region positioned between the adjacent semiconductor chips (23).