Substrate feed control

A method of controlling the feeding of substrates in a substrate processing apparatus having a plurality of processing chamber groups including at least one processing chamber group of a plurality of processing chambers for identically processing substrates concurrently therein, and a single substrate feeder for feeding substrates to the processing chamber groups, the method comprising the steps of:

• calculating respective times for the processing chamber groups by dividing the sums of times required to process substrates in the processing chambers and times required to feed substrates to the processing chambers, by the number of the processing chambers included in said processing chamber groups;
• establishing a time equal to or greater than a maximum one of the calculated times of each of the chamber groups, as a tact time;
• loading substrates to be processed into said substrate processing apparatus with the substrate feeder at intervals of said tact time;
• establishing a time equal to or greater than a time required for the substrate feeder to perform a feed job as a feed slot;
• establishing, in each tact time, a feed job schedule of feed slots assigned to feed jobs with respect to the processing chamber groups;
• feeding substrates into said substrate processing apparatus with said substrate feeder in timed relation to said feed slots according to said feed job schedule,
• wherein said substrate feeder has at least two holders for holding and feeding substrates at a time, said two holders being alternately operable to introduce substrates into or remove substrates from respective ones of said processing chambers at a time in each feed slot;
• establishing a sequence to feed a substrate to either one of the processing chambers of a first of the processing chamber groups, to feed a substrate from said either one of the processing chambers of the first processing chamber group to either one of the processing chambers of a second of the processing chamber groups and to unload a substrate from the second processing chamber group, said feed slots being arranged according to said sequence in said feed job schedule in each tact time;
• repeating feed job schedules in respective tact time to feed substrates to the processing chambers according to said sequence,
• wherein said substrate processing apparatus has another substrate feeder for loading substrates to be processed into the substrate processing apparatus and unloading processed substrates from the substrate processing apparatus;
• adding, to said feed job schedule in each tact time, feed slots for the another substrate feeder to load substrates into the substrate processing apparatus, prior to slots for the other substrate feeder to unload substrates from the substrate processing apparatus;
• and
• repeating feed job schedules in respective tact time to repeatedly load substrates into the substrate processing apparatus and unload substrates from the substrate processing apparatus.