Patterning device cooling apparatus

A patterning apparatus for a lithographic apparatus, the patterning apparatus comprising:

• a patterning device support structure configured to support a patterning device;
• a patterning device conditioning system comprising at least one first gas outlet configured to provide a gas flow over a surface of the patterning device and at least one second gas outlet configured to provide a gas flow over a part of a surface of the patterning device support structure not supporting the patterning device;
• and
• a control system configured to control a value of parameter of gas exiting the at least one first gas outlet to be a different value than that parameter of gas exiting the at least one second gas outlet or control a value of parameter of gas exiting the at least one second gas outlet to be a different value than that parameter of gas exiting the at least one first gas outlet.

A patterning apparatus for a lithographic apparatus, the patterning apparatus comprising:

• a patterning device support structure configured to support a patterning device;
• a patterning device conditioning system comprising:
• at least one first gas outlet configured to provide a gas flow over a surface of the patterning device;
• and
• at least one second gas outlet configured to provide a gas flow over a part of a surface of the patterning device support structure not supporting the patterning device,
• wherein the at least one first gas outlet is independently controllable from the at least one second gas outlet.

A device manufacturing method using a lithographic apparatus, the method comprising:

• projecting a beam through a patterning device, wherein the beam is patterned by the patterning device;
• providing at least one first gas outlet providing a gas flow over a surface of the patterning device and at least one second gas outlet providing a gas flow over a part of a surface of the patterning device support structure not supporting the patterning device;
• controlling a value of parameter of gas exiting the at least one first gas outlet to be a different value than that parameter of gas exiting the at least one second gas outlet or control a value of parameter of gas exiting the at least one second gas outlet to be a different value than that parameter of gas exiting the at least one first gas outlet;
• and
• directing the beam onto a substrate.