Soldering is essential technique for assembly of parts of cars, devices, IC’s, and so on. The main component of solder is tin. We electrochemically analyzed the oxidation rate of tin because the oxide thickness affects the strength of oxide film on tin surface. The thickness were measured with TEM, SERA, and AES. The film layer order is SnO/ SnO2/Sn. Though equilibrium phase diagrams shows that SnO2 is the most stable state at the exposure condition, SnO was formed. The reduction of tin oxide at NaCl solution is carried out in order to improve the wettability. Tin oxide was reduced about 1nm. Then, pitting was occurred and the wettability of Tin is improved.
