| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cleaning liquid which has a higher capability for removing org. dirt than that of an SPM cleaning liquid by dissolving peroxodisulfuric acid or peroxomonosulfuric acid or a salt thereof in pure water. SOLUTION: Peroxodisulfuric acid or peroxomonosulfuric acid or a salt thereof is dissolved in ultrapure water having an electrical resistivity (25 deg.C) of 18 MΩ.cm or higher, an org. carbon content of 10μg/l or lower, and a fine particle content of 10, 000/l or lower, in a concn. of the acid or salt of 0.01-10 g/l, pref. 0.05-5 g/l, or is dissolved in a mixture of 98 wt.% sulfuric acid and 30 wt.% aq. hydrogen peroxide soln. in a vol. ratio of about 4/1 or in a soln. obtd. by diluting the mixture with 2-4 times (by vol.) as much water, in a concn. of the acid or sal of 0.05-50 g/l, pref. 0.1-10 g/l. Thus, the amts. of chemicals used can be reduced.
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