Passivation method and heat treatment apparatus

Abstract

A chamber in a heat treatment apparatus is made of stainless steel. After pressure in the chamber is reduced, ozone is introduced into the chamber, and is sealed in the chamber by stopping the supply and exhaust of gas to and from the chamber. The ozone is kept sealed in the chamber for a waiting time period that is not greater than the half-life of ozone. The ozone having an extremely strong oxidizing power acts on an inner surface of the chamber made of stainless steel, whereby an inert passive film is formed on the inner surface. This inert passive film suppresses the precipitation of manganese from the chamber made of stainless steel. This prevents metal contamination of a semiconductor wafer from the chamber even when the semiconductor wafer is subjected to heating treatment in the chamber.

Dependencies are inferred from the claim text.