Method of forming electrode for semiconductor device

A semiconductor device, comprising:

• an electrode pad formed on a first face of a semiconductor substrate via a first insulating film;
• and a penetrating electrode which connects the electrode pad and an external connection terminal on a second face of the semiconductor substrate,
• wherein
• a penetrating hole is formed in the semiconductor substrate having the first insulating film and the electrode pad formed on the first face thereof, the penetrating hole being immediately below the electrode pad,
• a second insulating film is formed of an inner wall of the penetrating hole and on the second face of the semiconductor substrate,
• the first insulating film immediately below the electrode pad is opened so as to expose a back face of the electrode pad to a second face side of the semiconductor substrate, and a side face of an opening part of the first insulating film is exposed at the inner wall of the penetrating hole;
• and
• wherein said second insulating film is integrally formed and of the same material on both the inner wall of the penetrating hole and the second face of the semiconductor substrate.