Abstract:
A method of patterning lithographic substrates, the method comprising using a free electron laser to generate EUV radiation and delivering the EUV radiation to a lithographic apparatus which projects the EUV radiation onto lithographic substrates, wherein the method further comprises reducing fluctuations in the power of EUV radiation delivered to the lithographic substrates by using a feedback-based control loop to monitor the free electron laser and adjust operation of the free electron laser accordingly.
Abstract:
An EUV optical apparatus includes a number of adjustable mirrors (22x) on mirror bodies (120). Each mirror body is supported on an actuator (l00x) comprising a moving part (132, 134, 136) and a fixed casing part (128, 130). The actuator provides a resilient support (140, 142) for the mirror body so that it is tiltable with two degrees relative to the casing. An electromagnetic motor (166, 170-178) applies first part, under the influence of an applied motive force, the resilient mounting being arranged to provide a biasing force that resists said motive force. A magnetic coupling (102, 104a, 104b) is arranged between the moving and fixed parts so as to provide a counter-biasing force. The counter-biasing force partly opposes said biasing force and thereby reduces the motive force required to effect a given displacement. The actuator can thus be made with reduced size, weight and heat dissipation.
Abstract:
An illumination system includes a field-facet mirror-device and a pupil mirror configured to condition a beam of radiation incident on the field-facet mirror-device. The field-facet mirror-device includes reflective field facets movable between first and second orientations relative to the incident beam. The field facets in their first orientations are effective to reflect the incident radiation towards respective reflective pupil facets so as to form part of a conditioned beam reflected from the pupil-facet mirror-device. The field facets in their second orientations are effective to reflect the incident radiation onto respective areas of the pupil-facet mirror-device designated as beam dump areas. The areas are arranged to prevent radiation incident on the areas from forming part of the conditioned beam and are arranged between the limits of an annular area on the pupil-facet mirror-device effective to define the inner and outer regions of the conditioned beam reflected from the pupil-facet mirror-device.
Abstract:
An optical apparatus having a moveable reflective element (110) and associated actuator (109) is disclosed. The actuator comprises a first magnet (113) which is connected to the moveable reflective element such that movement of the first magnet will cause the moveable ref lectiveelement to move, and a second magnet (114) which is connected to a motor (116) such that operation of the motor will cause the second magnet to move, wherein the second magnet is positioned relative to the first magnet such that moving the second magnet will cause the first magnet to move.
Abstract:
An actuator system is provided that is configured to move a component relative to a base of the actuator system. The actuator system includes first and second actuating elements, each comprising two sections of material that are joined to each other and have different coefficients of thermal expansion. The two actuating elements are configured such that if the temperature of one is increased it applies a force on the component in a direction that is opposite to the force applied by the other actuating element if its temperature is increased. The actuator system further includes at least one power supply configured to provide independently controllable heating to the first and second actuating elements.
Abstract:
An actuator to displace, for example a mirror, provides movement with at least two degrees of freedom by varying the currents in two electromagnets. A moving part includes a permanent magnet with a magnetic face constrained to move over a working area lying substantially in a first plane perpendicular to a direction of magnetization of the magnet. The electromagnets have pole faces lying substantially in a second plane closely parallel to the first plane, each pole face substantially filling a quadrant of the area traversed by the face of the moving magnet. An optical position sensor may direct a beam of radiation at the moving magnet through a central space between the electromagnets. The sizes of facets in a pupil mirror device may be made smaller in a peripheral region, but larger in a central region, thereby relaxing focusing requirements.
Abstract:
An illumination system having a plurality of reflective elements, the reflective elements being movable between different orientations which direct radiation towards different locations in a pupil plane, thereby forming different illumination modes, is described. Each reflective element is moveable to a first orientation in which it directs radiation to a location in an inner illumination location group, to a second orientation in which it directs radiation to a location in an intermediate illumination location group, and to a third orientation in which it directs radiation to a location in an outer illumination location group. The reflective elements are configured to be oriented such that they can direct equal amounts of radiation towards the inner, intermediate and outer illumination location groups, and are configured to be oriented such that they can direct substantially no radiation into the outer illumination location group and direct substantially equal amounts of radiation towards the inner and intermediate illumination location groups.
Abstract:
A delivery system for use within a lithographic system. The beam delivery system comprises optical elements arranged to receive a radiation beam from a radiation source and to reflect portions of radiation along one or more directions to form a one or more branch radiation beams for provision to one or more tools.
Abstract:
A method of patterning lithographic substrates that includes using a free electron laser to generate EUV radiation and delivering the EUV radiation to a lithographic apparatus which projects the EUV radiation onto lithographic substrates. The method further includes reducing fluctuations in the power of EUV radiation delivered to the lithographic substrates by using a feedback-based control loop to monitor the free electron laser and adjust operation of the free electron laser accordingly, and applying variable attenuation to EUV radiation that has been output by the free electron laser in order to further control the power of EUV radiation delivered to the lithographic apparatus.