Abstract: 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.

Abstract: A lithographic apparatus comprises a beam modifying apparatus mounted in the path of a beam of radiation. The beam modifying apparatus comprises a conduit configured to allow the flow of a fluid through it, the conduit being arranged such that, in use, the beam of radiation passes through the conduit and the fluid flowing through it. The beam modifying apparatus further comprises a heat exchanger in thermal communication with a portion of the conduit located upstream, having regard to the direction of the fluid flow, of the location at which the beam of radiation passes through the conduit.

Abstract: A radiation source suitable for providing a beam of radiation to an illuminator of a lithographic apparatus. The radiation source comprises a nozzle configured to direct a stream of fuel droplets along a trajectory towards a plasma formation location. The radiation source is configured to receive a first amount of radiation such that, in use, the first amount of radiation is incident on a fuel droplet at the plasma formation location, and such that, in use, the first amount of radiation transfers energy to the fuel droplet to generate a radiation generating plasma that emits a second amount of radiation. The radiation source further comprises a first sensor arrangement configured to measure a property of the first amount of radiation that is indicative of a focus position of the first amount of radiation; and a second sensor arrangement configured to measure a property of a fuel droplet that is indicative of a position of the fuel droplet.

Abstract: A lithographic apparatus is disclosed that includes a support constructed to support a patterning device, the patterning device being capable of imparting a radiation beam with a pattern in its cross-section to form a patterned radiation beam and a substrate table constructed to hold a substrate. Further, the lithographic apparatus includes a projection system configured to project the patterned radiation beam onto a target portion of the substrate, the projection system being mounted to a reference element of the lithographic apparatus by a resilient mount to reduce a transfer of high frequency vibration from the reference element to the projection system and a control system to counteract a position error of the substrate table and the support relative to the projection system.

Abstract: 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.

Abstract: A control method is provided for controlling a heating of a thermal optical element, the thermal optical element having a matrix of heater elements. The method includes stabilizing a nominal temperature of the thermal optical element with a feedback loop to control the heating of heater elements; providing a desired temperature profile of the thermal optical element by a set point signal; determining a feedforward control of the heater elements from the set point signal; and forwardly feeding an output of the feedforward control into the feedback loop.

Abstract: A lithographic apparatus comprises a beam modifying apparatus mounted in the path of a beam of radiation. The beam modifying apparatus comprises a conduit configured to allow the flow of a fluid through it, the conduit being arranged such that, in use, the beam of radiation passes through the conduit and the fluid flowing through it. The beam modifying apparatus further comprises a heat exchanger in thermal communication with a portion of the conduit located upstream, having regard to the direction of the fluid flow, of the location at which the beam of radiation passes through the conduit.

Abstract: A control method is provided for controlling a heating of a thermal optical element, the thermal optical element having a matrix of heater elements. The method includes stabilizing a nominal temperature of the thermal optical element with a feedback loop to control the heating of heater elements; providing a desired temperature profile of the thermal optical element by a set point signal; determining a feedforward control of the heater elements from the set point signal; and forwardly feeding an output of the feedforward control into the feedback loop.

Abstract: A control method is provided for controlling a heating of a thermal optical element, the thermal optical element having a matrix of heater elements. The method includes stabilizing a nominal temperature of the thermal optical element with a feedback loop to control the heating of heater elements; providing a desired temperature profile of the thermal optical element by a set point signal; determining a feedforward control of the heater elements from the set point signal; and forwardly feeding an output of the feedforward control into the feedback loop.

Abstract: A lithographic apparatus is disclosed that includes an optical arrangement having an array of optical elements arranged in a plane perpendicular to the radiation beam. Each optical element comprises an electrical heating device to change an optical path length of the radiation beam. By selectively actuating the electrical heating devices, a position dependent change in optical path length can be achieved in order to correct for irradiation-induced optical path length errors.

Abstract: A lithographic apparatus is disclosed that includes an optical arrangement having an array of optical elements arranged in a plane perpendicular to the radiation beam. Each optical element comprises an electrical heating device to change an optical path length of the radiation beam. By selectively actuating the electrical heating devices, a position dependent change in optical path length can be achieved in order to correct for irradiation-induced optical path length errors.

Abstract: A lithographic apparatus is disclosed that includes a support constructed to support a patterning device, the patterning device being capable of imparting a radiation beam with a pattern in its cross-section to form a patterned radiation beam and a substrate table constructed to hold a substrate. Further, the lithographic apparatus includes a projection system configured to project the patterned radiation beam onto a target portion of the substrate, the projection system being mounted to a reference element of the lithographic apparatus by a resilient mount to reduce a transfer of high frequency vibration from the reference element to the projection system and a control system to counteract a position error of the substrate table and the support relative to the projection system.