Laser system for target metrology and alteration in an euv light source
AssigneeASML Netherlands B.V.
InventorsRobert Jay Rafac, Igor Vladimirovich Fomenkov
Life of this patent
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Abstract
Disclosed is a system and method for generating EUV radiation in which a laser is used in a multistage process to illuminate without altering a target material and then irradiate the target material to alter a target material with the illumination stage being used to determine the timing for firing during the irradiation stage or stages.
Claims27
Apparatus comprising:
- a laser system configured to generate metrology radiation and operational radiation from a single laser source;
- a first optical system arranged to convey the metrology radiation along a first optical path to an irradiation region;
- a second optical system arranged to convey reflected metrology radiation reflected by target material in the irradiation region;
- metrology module arranged to receive the reflected metrology radiation and configured to perform an analysis of the reflected metrology radiation and to generate a control signal based at least in part on the analysis;
- and
- a steering module arranged to receive the control signal and configured to steer the operational radiation in response to the control signal, the first optical system conveying the operational radiation to an irradiation site in the irradiation region.
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A radiation source having a laser configured to have a first state in which the laser generates metrology radiation and a second state in which the laser generates operational radiation, the radiation source being responsive to a control signal to transition from the first state to the second state.
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A method of using a radiation source including a laser to irradiate target material, the method comprising the steps of:
- causing the laser to emit a metrology pulse;
- using the target material to reflect at least a portion of a reflected portion of the metrology pulse;
- determining a timing for the laser to emit an operational pulse based at least in part on whether the at least a portion of the reflected portion meets a predetermined criterion;
- and
- causing the laser to emit the operational pulse at the timing as determined.
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A method of using a radiation source including a laser to irradiate target material, the method comprising the steps of:
- controlling a beamwidth of a focusing module to increase the beamwidth of a beam passing through the focusing module;
- causing the laser to emit a metrology pulse through the focusing module;
- using the target material to reflect at least a portion of a reflected portion of the metrology pulse;
- using the at least a portion of a reflected portion of the metrology pulse to determine a position of the target material;
- determining a timing for emission by the laser of an operational pulse based at least in part on the position of the target material as determined;
- controlling the beamwidth of a focusing module to decrease the beamwidth of a beam passing through the focusing module;
- and
- causing the laser to emit the operational pulse through the focusing module at the timing as determined.
Dependencies are inferred from the claim text.