CLEANING METHOD OF SILICON MATERIAL

PURPOSE:To restrain particles or heavy metal impurities from being attached to the surface of a silicon material so as not to produce micro irregularities on it by a method wherein a mixed liquid of hydrofluoric acid and hydrochloric acid is used in a final cleaning process carried out after a pre-cleaning process. CONSTITUTION:In a pre-cleaning process (defined as a main cleaning process to a final cleaning process as a finish cleaning process), an ammonia.hydrogen dioxide treatment 1a and a hydrochloric acid.hydrogen dioxide treatment 1b are carried out, wherein a mixed solution composed of ammonia, hydrogen dioxide, and pure water is used in a treatment 1a to mainly remove organic material attached to a work, and another mixed solution composed of hydrochloric acid, hydrogen dioxide, and pure water is used in a treatment 1b to chiefly remove heavy metal impurities attached to the work. Lastly, in a final cleaning process II, a cleaning liquid composed of dilute hydrochloric acid and dilute hydrofluoric acid is used. Thereafter, the work is cleaned with pure water in a final rinsing process.