Wet processing apparatus, wet processing method and storage medium

A wet processing apparatus for processing substrates by pouring a processing liquid supplied by a processing liquid supply system onto the substrates, said wet processing apparatus comprising:

• 2n processing units arranged in a lateral row and respectively including 2n substrate holders for supporting a substrate in a horizontal position and 2n splash cups respectively surrounding the substrate holders, and divided into a first group of the n processing units on the left side and a second group of the n processing units on the right side, n being an integer not smaller than 2;
• a first nozzle unit to be used exclusively for the n processing units of the first group in a normal processing mode;
• a first nozzle support mechanism supporting the first nozzle unit and capable of laterally moving the first nozzle unit to all the 2n processing units;
• a second nozzle unit to be used exclusively for the n processing units of the second group in a normal processing mode;
• a second nozzle support mechanism supporting the second nozzle and capable of laterally moving the second nozzle unit to all the 2n processing units;
• a substrate carrying mechanism for transferring a substrate to and receiving a substrate from the substrate holders;
• and
• a controller which provides control signals for controlling the substrate carrying mechanism to deliver substrates alternately to the processing unit of the first group and that of the second group so as to use the processing units of the first and the second group in order in a normal processing mode, and for moving the first nozzle unit for the processing units of the first group to use the first nozzle unit for processing substrates by the serviceable ones of the processing units of the second group when the processing unit of the second group becomes unable to process substrates due to the inoperativeness of the substrate holder, the processing solution supply system or the nozzle support mechanism or for moving the second nozzle unit for the processing units of the second group to use the second nozzle unit for processing substrates by the serviceable ones of the processing units of the first group when the processing unit of the first group becomes unable to process substrates due to the inoperativeness of the substrate holder, the processing solution supply system or the nozzle support mechanism.