Substrate transport method, substrate transport apparatus, and coating and developing system

A substrate transport method that is performed in a substrate processing system, the substrate processing system including a substrate transport apparatus, which has a holding unit configured to hold the substrate by vacuum suction and which is configured to transport the substrate held by the holding unit, the substrate processing system further including a plurality of placement locations each allowing the substrate transported by the substrate transport apparatus to be placed thereon, said method comprising:

• receiving the substrate placed on one of the plurality of placement locations by the holding unit and holding the substrate by vacuum suction;
• retracting the holding unit from the one placement location with the holding unit holding the substrate;
• detecting a first positional deviation of the substrate from a reference position of the substrate on the holding unit;
• transporting the substrate held by the holding unit to a position facing another placement location;
• detecting a second positional deviation of the substrate from the reference position of the substrate on the holding unit, when the substrate is located at the position facing said another placement location;
• calculating, based on the first and second positional deviations, a positional displacement of the substrate relative to the holding unit that occurred during the transporting of the substrate to the position facing the another placement location;
• and
• determining whether or not the positional displacement thus calculated falls within a predetermined range.