摘要 |
After semiconductor wafers are loaded into a reaction vessel, and ruthenium (Ru) film or ruthenium oxide film is formed, the interior of the reaction vessel is efficiently cleaned without contaminating the wafers. The interior of the reaction vessel is heated to a temperature of above 850°C while the pressure inside the reaction vessel is reduced to, e.g., 133 pa (1 Torr) - 13.3 Kpa (100 Torr), and oxygen gas is fed into the reaction vessel at a flow rate of, e.g., above 1.5 Lm, whereby the ruthenium film or the ruthenium oxide film formed inside the reaction vessel is cleaned off. In place of oxygen gas, active oxygen, such as O3, O* and OH*, etc. may be used. |