DEVICE FOR MONITORING A RADIATION SOURCE, RADIATION SOURCE, METHOD OF MONITORING A RADIATION SOURCE, DEVICE MANUFACTURING METHOD

摘要

Capacitive measurements for monitoring vapor or deposits from a vapor in a radiation source for a lithography apparatus. The measurements may be used to control operation of the radiation source. In one particular arrangement measurements from a plurality of capacitors are used to distinguish between changes in capacitance caused by the vapor and changes in capacitance caused by deposits from the vapor.