A semiconductor device has through electrodes with property as an electrode and excellent in manufacturing stability. The through electrode composed of a conductive small diameter plug and a conductive large diameter plug is provided on the semiconductor device. A cross sectional area of the small diameter plug is made larger than a cross sectional area of a connection plug and its diameter each, and the cross sectional area of the small diameter plug is made smaller than a cross sectional area of the large diameter plug and its diameter each. Further, a projecting portion where the small diameter plug is projected from a silicon substrate is put into an upper face of the large diameter plug. Further, an upper face of the small diameter plug is connected to a first interconnect.
