| 摘要 |
PROBLEM TO BE SOLVED: To properly remove both metallic impurities and fine particles which adhere to the surface of a semiconductor substrate. SOLUTION: In a cleaning method, a contaminated semiconductor substrate 11 is cleaned with a cleaning solution, containing 0.1-50 wt.% organic acid and 0.005-0.25 wt.% hydrofluoric acid having a pH value of or less. When the substrate 11 is dipped in the cleaning solution, a natural oxide film 12 formed on the surface of the substrate 11 is removed by the hydrofluoric acid and the fine particles 13 and metallic impurities 14 on the film 12 and the metallic impurities 14 in the film 12 migrate into the solution. Since the cleaning solution is an acidic solution containing organic acid and has a pH value of 4 or less, the fine particles 13 are charged negatively similar to the surface of the substrate 11, and at the same time, the metallic impurity ions in the solution become negative complex ions due to the complexing effect of the organic acid. Consequently, the adhesion or re-adhesion of the fine particles 13 and metallic impurities 14 to the substrate 11 is prevented, because the surface potentials of the particles 13 and impurities 14 become negative, similar to that of the substrate 11.
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