Sn めっき上もしくははんだ上に発生するSnO ウィスカの研究

抄録

SnO whisker with a tube-like shape was found on Sn plating or on Sn-Ag-Cu solder after humidity testing (85 ℃ 85 %RH). The SnO whisker is an insulator and it has no risk of short circuit fault. However, the formation of SnO whisker may have risk of corrosion. The growth mechanism of the tube-like SnO whisker was investigated. The tube-like SnO whisker is formed by bromination of Sn plating or Sn-Ag-Cu solder and oxidation of the surface of tin bromide in 85 ℃ 85 %RH atmosphere. Br included in flux residues causes bromination of Sn plating and organic acid included in flux residues casues the insulation deterioration of the flux residues.