Passivation method and heat treatment apparatus

The invention provides a passivation method and a heat treatment apparatus capable of preventing metal contamination of a substrate from a chamber. The chamber of the heat treatment apparatus is formed of stainless steel. After the pressure in the chamber is reduced, ozone is introduced into the chamber, and the gas supply and the gas discharge are stopped to seal the ozone in the chamber. The state in which the ozone is sealed in the chamber is maintained during a stand-by time that is equal to or less than the half-life period of the ozone. An inert passive film is formed on an inner surface of a chamber formed from stainless steel by the action of ozone having an extremely strong oxidizing ability on the inner surface of the chamber. The inert passive film suppresses the deposition of manganese from the stainless steel chamber, so that metal contamination of the semiconductor wafer from the chamber can be prevented even when the semiconductor wafer is subjected to heat treatment in the chamber. 本发明提供一种能够防止