The semiconductor device is capable of coping with speedup of operation using a low dielectric constant material film other than silicon. The base (10) formed by the substrate (11) and the low dielectric constant material film (12) whose relative dielectric constant is lower than silicon is provided. The semiconductor element layer including the MOS transistor (30) is adhered onto the surface of the base (10) for stacking. The transistor (30) is formed by using the island-shaped single-crystal Si film (31) and buried in the insulator films (15), (16) and (17). The multilayer wiring structure (18) is formed on the semiconductor element layer and is electrically connected to the transistor (30). The electrode (20) functioning as a return path for the signals is formed on the back surface of the base (10). Instead of forming the electrode (20) on the base (10), the electrodes (20A) may be arranged on the back surface of the base (10A), configuring the base (10A) as an interposer.