Substrate processing apparatus, substrate processing method and storage medium

A non-transitory computer-readable recording medium storing a computer executable program that, when executed, causes a computer to perform a substrate processing method using a substrate processing apparatus that includes a processing liquid supplying unit that stores and supplies a processing liquid, a level gauge that detects a level of the processing liquid at the processing liquid supplying unit, a plurality of liquid processing units, a flow rate meter installed at a distribution pipe provided between the processing liquid supplying unit and the plurality of liquid processing units, a plurality of branch pipes provided for each of the plurality of liquid processing units, and a plurality of flow rate gauges installed at each of the plurality of branch pipes, the substrate processing method comprising:

• sequentially carrying a plurality of substrates into the plurality of liquid processing units;
• supplying a processing liquid from the processing liquid supply unit to the plurality of liquid processing units to conduct a liquid processing for each of the plurality of substrates;
• carrying one of the plurality of substrates out of the plurality of liquid processing units after the liquid processing is completed for the one of the plurality of substrates while the rest of the plurality of substrates remain in the liquid processing units;
• detecting an amount of the processing liquid remaining in the processing liquid supply unit using the level gauge while each of the liquid processing units is conducting a liquid processing for each of the plurality of substrates;
• carrying an unprocessed substrate into one of the plurality of liquid processing units where the one of the plurality of substrates completed with the liquid processing is carried out;
• when it is detected by the level gauge that the amount of the processing liquid remaining in the processing liquid supply units is below a predetermined threshold, suspending the carrying of the unprocessed substrate into one of the plurality of liquid processing units where the one of the plurality of substrates completed with the liquid processing is carried out while continuing the liquid processing for the plurality of substrates remaining in the processing units, thereby completing the liquid processing for the plurality of substrates remaining in the processing units;
• detecting a flow rate of the processing liquid supplied to each of the liquid processing units from the distribution pipe using a corresponding flow rate gauge installed at each of the plurality of branch pipes;
• when it is detected by the corresponding flow rate gauge that the supplying of the processing liquid to a corresponding liquid processing unit is suspended, suspending an operation of the corresponding liquid processing unit and recording an event that the liquid processing of the substrate in the corresponding liquid processing unit is incomplete;
• returning the processing liquid that is not used by the corresponding liquid processing unit to the processing liquid supply unit in a lump;
• detecting a flow rate of the processing liquid returning to the processing liquid supply unit using the flow rate meter;
• and
• when it is detected by the flow rate meter that the flow rate of the processing liquid returning to the processing liquid supply unit is below a predetermined threshold, suspending the liquid processing of the substrates in all of the operating processing units and recording an event that the liquid processing of the substrates in all of the operating liquid processing units is incomplete.