Method for manufacturing a substrate processing apparatus and a semiconductor device

PROBLEM TO BE SOLVED: To provide a wafer treatment apparatus that can form a film thickness not thinner than a constant thickness while securing the in-plane uniformity of an oxide film formed by using a batch-type semiconductor manufacturing device. SOLUTION: The wafer treatment apparatus 1 has a treatment furnace 202, a gas supply means for supplying an ozone gas into a treatment chamber 201 of the treatment furnace 202, a plasma generating means for generating plasma in the treatment chamber 201, a control means for controlling at least the gas supply means and the plasma generating means, and a gas discharge means for discharging an ambient atmosphere in the treatment chamber 201, wherein the gas supply means has an open/close valve and a buffer tank 503, the gas supply means is so controlled that, while the ozone gas is supplied by the gas supply means, the buffer tank is filled with the ozone gas by setting the open/close valve to "close" and the gas is supplied into the treatment chamber 201 by setting the open/close valve to "open", thus forming an oxide film on the surface of wafer 200, and when the ozone gas is supplied into the treatment chamber 201, plasma is controlled so as to be generated in the treatment chamber 201 by the plasma generating means, and the ozone gas is controlled so as to be excited, thus forming an oxide film. COPYRIGHT: (C)2009,JPO&INPIT