Kaori Watanabe

Removal of metal and organic contaminants from silicon substrates using electrolysis-ionized water containing ammonium chloride

The efficiency of removing metal and organic contaminants from silicon substrate surfaces by using electrolysis-ionized water containing ammonium chloride was compared with the removal efficiency using an ammonium hydroxide and hydrogen peroxide mixture and a hydrochloric acid and hydrogen peroxide mixture. Before and after wet cleaning, metal impurities were measured using hydrofluoric acid vapor-phase decomposition atomic absorption spectrometry, and the organic impurities were measured using thermal desorption spectroscopy gas chromatography mass spectrometry. The electrolysis anode water removed both metal and organic contaminants due to its high oxidation-reduction potential and low pH. Oxidation and oxidative degradation are effective for the removal of both metal and organic contaminants from silicon substrate surfaces, and metallic complex acids are stable at low pH of the electrolysis anode water. The electrolysis cathode water, on the other hand, cannot remove metal or organic contaminants because of its high pH and low oxidation-reduction potential.