Patent ID: 8217280

Claim:
A circuit board comprising: a substrate; a circuit pattern; a through electrode; and a dispersed area, wherein said circuit pattern is disposed on one side of said substrate in a thickness direction thereof, said through electrode is filled in a through-hole formed in said substrate with one end connected to said circuit pattern, and said dispersed area is an area in which said circuit pattern and said through electrode are connected to each other by dispersion and alloying of a dispersed metal component, and said dispersed metal component is dispersed to have such a concentration gradient that its dispersed amount is the highest at but decreases with distance from an interface between said circuit pattern and said through electrode, and said through electrode comprises high melting metal particles and low melting metal particles, and intermettalic bond is formed between said high melting metal particles and low metal particles, said high melting metal particles contain at least one component selected from the group consisting of Ag, Cu, Au, Pt, Ti, Zn, Al, Fe, Si and Ni, and the low melting metal particles have a composite structure and contain at least one component selected from the group consisting of Sn, In, and Bi.