EUV lithography system and method for decreasing debris in EUV lithography system

An extreme ultraviolet (EUV) lithography system, comprising:

• an EUV scanner configured to perform a lithography exposure process in response to EUV radiation;
• a light source, comprising:
• a chamber;
• a collector configured to collect the EUV radiation and direct the EUV radiation to the EUV scanner;
• a concentration detector configured to measure concentration of debris generated during the lithography exposure process in the chamber;
• and
• a debris collection device disposed in the chamber;
• an exhaust device configured to extract the debris out the light source according to a first gas flow rate corresponding to the measured concentration of the debris;
• and
• a gas supply device configured to provide a gas into the collector of the light source according to a second gas flow rate corresponding to the measured concentration of the debris,
• wherein a controller is configured to control a ratio of the second gas flow rate to the first gas flow rate to be greater than one.

A method for decreasing debris in an extreme ultraviolet (EUV) lithography system, comprising:

• measuring concentration of the debris in a chamber of a light source;
• extracting the debris out of the chamber according to a first gas flow rate of an exhaust device;
• providing a gas into the chamber according to a second gas flow rate of a gas supply device;
• in response to the measured concentration of the debris, adjusting the first gas flow rate of the exhaust device and the second gas flow rate of the gas supply device;
• and
• in response to a first control signal, performing a purge operation according to the adjusted first gas flow rate of the exhaust device and the adjusted second gas flow rate of the gas supply device,
• wherein the first control signal indicates a lithography exposure process has been completed,
• wherein the adjusted first gas flow rate is proportional to the adjusted second gas flow rate, and a ratio of the adjusted second gas flow rate to the adjusted first gas flow rate is greater than one.