Radiation Source

摘要

A radiation source (SO) suitable for providing a beam of radiation to an illuminator of a lithographic apparatus. The radiation source comprises a nozzle (128) configured to direct a stream of fuel droplets along a trajectory (140) towards a plasma formation location (212). The radiation source is configured to receive a first amount of radiation (205) such that, in use, the first amount of radiation is incident on a fuel droplet at the plasma formation location. The first amount of radiation transfers energy to the fuel droplet to generate a radiation generating plasma that emits a second amount of radiation (132). The radiation source further comprises an alignment detector having a first sensor arrangement (122) and a second sensor arrangement (134). The first sensor arrangement is configured to measure a property of a third amount of radiation (205a) that is indicative of a focus position of the first amount of radiation. The second sensor arrangement is configured to measure a property of a fourth amount of radiation (138), the fourth amount of radiation being a portion of the first amount of radiation that is reflected by the fuel droplet upon which the first amount of radiation is incident.

主权项

1. A radiation source suitable for providing a beam of radiation to an illuminator of a lithographic apparatus, the radiation source comprising:
a nozzle configured to direct a stream of fuel droplets along a trajectory towards a plasma formation location; the radiation source configured to receive a first amount of radiation such that; the first amount of radiation is incident on a fuel droplet at the plasma formation location; the radiation source further comprising an alignment detector having a first sensor arrangement and a second sensor arrangement; the first sensor arrangement configured to measure a property of a third amount of radiation that is indicative of a focus position of the first amount of radiation; and the second sensor arrangement configured to measure a property of a fourth amount of radiation, the fourth amount of radiation comprising a portion of the first amount of radiation that is reflected by the fuel droplet upon which the first amount of radiation is incident.