| abstract |
An electrode structure has a Cu electrode that provided in a surface of a substrate, a diffusion preventing film that is made of a material in which a diffusion coefficient of Sn is equal to or lower than 3×10 −23 cm 2 /sec, the whole Cu electrode being covered with the diffusion preventing film, and a solder layer that is provided above the diffusion preventing film, the solder layer being made of Au—Sn solder. |