Electronic device and fabrication method thereof

An electronic device comprising:

• a first semiconductor substrate on which a bonding projection section is projected via an insulation film;
• a second semiconductor substrate that is bonded by welding to the bonding projection section of the first semiconductor substrate via conductive bonding material;
• a through hole that has a main hole penetrating the bonding projection section and a sub-hole penetrating the insulation film and having a cross sectional area which is formed to be larger than a cross sectional area of the main hole;
• and
• a conduction wiring section that is formed by the conductive bonding material filled in the through hole at a time of the bonding by welding and that conducts the first semiconductor substrate with the second semiconductor substrate.