OPTICAL SENSORS FOR MEASURING PROPERTIES OF CONSUMABLE PARTS IN A SEMICONDUCTOR PLASMA PROCESSING CHAMBER

A method of manufacturing semiconductor devices includes repeatedly performing a transfer operation which transfers each of a plurality of semiconductor wafers between a substrate handling module and a processing chamber through a wafer access port, the processing chamber including at least one consumable component. Using the processing chamber, a semiconductor manufacturing process is performed on each of the plurality of semiconductor wafers; and detecting an optical signal from the at least one consumable component during a time when the processing chamber is not performing the semiconductor manufacturing process on the wafers.