PURPOSE:To enhance the mounting density of a semiconductor device such as a memory device, etc., by connecting the bump electrodes of a semiconductor chip to leads, and connecting the plurality of the chips having the leads to the interconnections of a module board to compose a semiconductor device. CONSTITUTION:The bump electrodes 6 of a semiconductor chip 4 are connected to leads 5, and a plurality of semiconductor chips 4 having the leads 5 are connected to the interconnections of a module board 1 to compose a semiconductor device. For example, eight semiconductor chips 4A to 4D are mounted on the front and rear faces of the board 1 composed by laminating a plurality of ceramic and interconnecting layers. The chips 4A to 4D are not sealed by a package made of ceramics, resin, etc., but the side provided with semiconductor elements and interconnections is molded with resin 7. Bump electrodes 6 are provided on the chips 4A to 4D, and the leads 5A to 5D are connected to the electrodes 6 by TABs.