Patent ID: 8268396

Claim:
A film forming method for forming a thin film on a substrate by causing a chemical reaction of a source gas produced from a solid or a liquid source material on a surface of a substrate in a processing chamber by using a film forming apparatus including a processing chamber having a supply port for supplying the source gas and a exhaust port for exhausting a gas, a mounting table which is disposed in the processing chamber and mounts thereon the substrate, and an adsorption/desorption member for adsorbing and desorbing the source gas by changing a surface temperature thereof, the film forming method comprising the steps of: (a) setting a temperature of an inner wall of the processing chamber higher than or equal to a temperature TA at which the source material is sublimated or evaporated and lower than a temperature TB at which a chemical reaction takes place on the surface of the substrate; (b) setting a surface temperature of the adsorption/desorption member lower than the temperature TA, supplying the source gas into the processing chamber through the supply port while closing the exhaust port, and adsorbing the source gas in a solid or a liquid state onto the surface of the adsorption/desorption member while closing the supply port; (c) setting a temperature of the substrate mounted on the mounting table in the processing chamber higher than or equal to the temperature TB, setting the surface temperature of the adsorption/desorption member higher than or equal to the temperature TA, and causing a chemical reaction of the source gas desorbed from the surface of the adsorption/desorption member on the surface of the substrate to form a film on the substrate; and (d) replacing the source gas in the processing chamber with a purge gas.