Silicon interposer and method for manufacturing the same

A silicon interposer comprising:

• a silicon substrate, said silicon substrate having a first surface and a second surface and defining a through hole that extends from said first surface to said second surface;
• an element portion made of an impurity diffusion layer, the element portion being formed on said first surface of the silicon substrate;
• a protection film that covers a surface of the element portion and said first surface of said silicon substrate, said protection film being made of a SiN film;
• a contact portion provided in the protection film and connected to said element portion;
• a through electrode, said through electrode being received in said through hole and passing through the protection film and the silicon substrate in a thickness direction from said first surface to said second surface;
• an oxide film formed on inner wall surfaces of the through hole and said second surface of said silicon substrate, said oxide film, which is formed of a material that is different than said SiN film, electrically insulates the through electrode from the silicon substrate;
• a first plurality of wirings formed on said protection film;
• and,
• a second plurality of wirings formed on the second surface of the silicon substrate, wherein
• one of the first plurality of wirings, which is formed on the protection film, is connected electrically to the element portion via the contact portion.