摘要 |
A combination of a first surface treating solution comprising an inorganic or organic alkali such as ammonia or a quaternary ammonium hydroxide, hydrogen peroxide, water and a second surface treating solution of ultra-pure water, at least one of the first and second surface treating solutions containing as a complexing agent a compound having one or more phosphonic acid groups in the molecule and showing chelating ability, or an oxidized form thereof, or polyphosphoric acid or a salt thereof, is effective for making semiconductor surfaces free from harmful metallic impurities such as Fe, A?, Zn, etc.
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