Radiation source

A lithographic apparatus arranged to project a pattern from a patterning device onto a substrate, wherein the lithographic apparatus comprises at least one secondary radiation source and a radiation source configured to provide a beam of radiation to the patterning device along an optical axis, the radiation source comprising:

• a nozzle configured to direct a stream of fuel droplets along a trajectory towards a plasma formation location;
• and
• the radiation source being configured to receive a first amount of radiation from the at least one secondary radiation source such that the first amount of radiation is incident on a fuel droplet at the plasma formation location, and such that the first amount of radiation transfers energy into the fuel droplet to generate a modified fuel distribution, the modified fuel distribution having a surface;
• the radiation source being configured to receive a second amount of radiation from the at least one secondary radiation source such that the second amount of radiation is incident on a portion of the surface of the modified fuel distribution, the second amount of radiation having a p-polarized component with respect to portion of the surface;
• and such that the second amount of radiation transfers energy to the modified fuel distribution to generate a radiation generating plasma, the radiation generating plasma emitting a third amount of radiation;
• the radiation source further comprising a collector configured to collect and direct at least a portion of the third amount of radiation along the optical axis towards the patterning device;
• wherein the radiation source is configured such that the second amount of radiation propagates in a first direction, the first direction being non-parallel to a normal to the portion of the surface of the modified fuel distribution.

A device manufacturing method using a lithographic apparatus, the lithographic apparatus comprising at least one secondary radiation source, a patterning device and a radiation source having nozzle, a plasma formation location and a collector, the method comprising:

• directing a stream of fuel droplets from the nozzle along a trajectory towards the plasma formation location;
• producing a first amount of radiation from the at least one radiation source such that the first amount of radiation is incident on a fuel droplet at the plasma formation location;
• transferring energy from the first amount of radiation into the fuel droplet to generate a modified fuel distribution, the modified fuel distribution having a surface;
• producing a second amount of radiation having a p-polarized component with respect to a portion of the surface from the at least one radiation source such that the second amount of radiation is incident on the portion of the surface of the modified fuel distribution;
• transferring energy from the second amount of radiation to the modified fuel distribution to generate a radiation generating plasma, the radiation generating plasma emitting a third amount of radiation;
• collecting at least a portion of the third amount of radiation at the collector to produce a radiation beam;
• directing the radiation beam from the collector along an optical axis towards the patterning device,
• producing a patterned radiation beam using the patterning device;
• and
• projecting the patterned radiation beam onto a substrate;
• wherein the second amount of radiation propagates in a first direction, the first direction being non-parallel to a normal to the portion of the surface of the modified fuel distribution.