Heat treatment method and heat treatment apparatus for heating substrate by light irradiation

A heat treatment apparatus for heating a substrate implanted with impurities by irradiating the substrate with flash light, comprising:

• a chamber for housing a substrate in which a carbon or carbon compound thin film is formed on a surface thereof after being implanted with impurities;
• a holding part for holding said substrate in said chamber;
• a preheating part for preheating said substrate held by said holding part;
• a flash lamp for emitting flash light to said substrate held by said holding part;
• an oxygen gas supply part for supplying oxygen gas from around said substrate held by said holding part in said chamber;
• an exhaust part for exhausting the atmosphere in said chamber from below said substrate held by said holding part;
• and
• a control part configured to control said preheating part to heat said substrate held by said holding part, control said oxygen gas supply part to supply oxygen gas while controlling said exhaust part to exhaust the atmosphere from said chamber, to thereby make the film thickness smaller from the central portion of said thin film formed on said surface of said substrate toward the peripheral portion thereof, and then control said flash lamp to emit flash light.