Substrate processing apparatus and substrate processing method

A substrate processing apparatus to etch a molybdenum film of a substrate having a device structure that includes, in a multistage manner, multilayer films including the molybdenum film, the apparatus comprising:

• a processing tank that retains therein etchant including acetic acid, phosphoric acid, nitric acid, and water as components;
• a supply unit that supplies acetic acid, phosphoric acid, nitric acid, and water individually or as the etchant to the processing tank;
• an open/close valve that opens/closes a liquid discharging passage of the processing tank;
• a concentration measuring unit that measures a concentration for each of the components of the etchant retained in the processing tank;
• a liquid amount measuring unit that measures an amount of the etchant retained in the processing tank;
• and
• a controller that controls the open/close valve and the supply unit to execute a discharging and replenishing process including:
• discharging a part of the etchant from the processing tank;
• and
• replenishing the processing tank with acetic acid, phosphoric acid, and nitric acid, wherein
• in the discharging and replenishing process, the controller is configured to:
• based on concentrations of the respective components measured by the concentration measuring unit, an amount of the etchant measured by the liquid amount measuring unit, a preliminarily-set target amount of the etchant, and preliminarily-set target concentrations of the respective components;
• decide a discharging amount of the etchant from the processing tank, and replenishing amounts of acetic acid, phosphoric acid, and nitric acid to the processing tank;
• control the open/close valve to discharge the decided discharging amount of the etchant from the processing tank;
• and
• control the supply unit to replenish the processing tank with the decided replenishing amounts of acetic acid, phosphoric acid, and nitric acid.