Patent ID: 8590484

Claim:
A substrate processing apparatus comprising: a substrate processing chamber configured to accommodate a substrate; a source gas supply unit configured to supply a source gas to the substrate processing chamber; a modification gas supply unit configured to supply a modification gas to the substrate processing chamber; an inert gas supply unit configured to supply an inert gas to the substrate processing chamber; an exhaust unit configured to exhaust an inside atmosphere of the substrate processing chamber; and a control unit configured to control the source gas supply unit, the modification gas supply unit, the inert gas supply unit and the exhaust unit, wherein the inert gas supply unit comprises: an inert gas supply pipe connected to the substrate processing chamber; a first inert gas on-off valve configured to open and close the inert gas supply pipe; and a gas tank installed at an upstream side of the first inert gas on-of valve, wherein the control unit is configured to: (a) cause the inert gas supply unit to close the first inert gas on-off valve to store the inert gas in the gas tank during a supply of the source gas to the substrate processing chamber; (b) cause the inert gas supply unit to open the first inert gas on-off valve to supply the inert gas from the gas tank to the substrate processing chamber after the supply of the source gas is stopped such that an inside pressure of the substrate processing chamber after the supply of the source gas is stopped is higher than an inside pressure during the supply of the source gas; (c) cause the inert gas supply unit to close the first inert gas on-off valve to store the inert gas in the gas tank during a supply of the modification gas to the substrate processing chamber; and (d) cause the inert gas supply unit to open the first inert gas on-off valve to supply the inert gas from the gas tank to the substrate processing chamber after the supply of the modification gas is stopped such that an inside pressure of the substrate processing chamber after the supply of the modification gas is stopped is higher than an inside pressure during the supply of the modification gas.