Radiation source apparatus and method for decreasing debris in radiation source apparatus

A radiation source apparatus, comprising:

• a light source configured to provide an extreme ultraviolet (EUV) radiation, comprising:
• a chamber;
• a collector configured to collect the EUV radiation and direct the EUV radiation in the chamber;
• a measuring device configured to measure concentration of debris generated during the lithography exposure process in the chamber;
• a debris collection device disposed in the chamber;
• and
• a controller configured to adjust a first gas flow rate according to the measured concentration of the debris when the lithography exposure process is completed, so as to perform a purge operation in the chamber;
• and
• an exhaust module configured to extract the debris out a space defined by the collector and the debris collection device according to the first gas flow rate.

A method for decreasing debris in a radiation source apparatus, comprising:

• measuring concentration of the debris in a chamber;
• extracting the debris out of the chamber according to a first gas flow rate of an exhaust module;
• providing a gas into the chamber according to a second gas flow rate of a gas supply module;
• and
• in response to the measured concentration of the debris, performing a purge operation to synchronically adjust the first gas flow rate of the exhaust module and the second gas flow rate of the gas supply module.