Abstract: Method and apparatus for generating broadband radiation. The method includes directing pulsed pump radiation through a moving nonlinear medium, and thereby generating, through spectral broadening, broadband radiation from the pulsed pump radiation inside the moving nonlinear medium. The power of the pump radiation inside the moving nonlinear medium is at least a critical power for initiating filamentation within the moving nonlinear medium.

Abstract: An assembly and method for separating first radiation and second radiation in the far field, wherein the first radiation and the second radiation have non-overlapping wavelengths, The assembly comprises a capillary structure, wherein the first radiation and the second radiation propagate coaxially along at least a portion of the capillary structure, and an optical structure configured to control the spatial distribution of the first radiation outside of the capillary structure, through interference, such that the intensity of the first radiation in the far field is reduced along an optical axis of the second radiation.

Abstract: An assembly comprises a space configured for placing a medium to receive a first radiation for generating a second radiation. In operation, the second radiation propagates coaxially with the first radiation after the medium. The assembly further comprises an optical element after the medium for transmitting or reflecting the first radiation with a surface area. The assembly is configured such that, in operation, a cleaning gas is in contact with the surface area. A reactive medium is generated from at least a part of the cleaning gas by the second radiation for removing a contamination from the surface area.

Abstract: Disclosed is a pellicle membrane comprising three or more layers, the three or more layers comprising at least one inner layer and at least one outer layer on either side of said at least one inner layer, wherein the at least one inner layer comprises and/or consists of one or more of boron, zirconium, beryllium, niobium, yttrium, molybdenum and/or carbon and/or one or more compounds of each of these materials. Also disclosed is a metrology apparatus which uses such a pellicle membrane as a beamsplitter and/or filter.

Abstract: A beam metrology device for determining at least one characteristic of first radiation and/or at least one characteristic of second radiation, said second radiation being generated via a first nonlinear process upon receiving a first portion of the first radiation; the beam metrology device comprising: a metrology device nonlinear medium configured to receive a second portion of the first radiation and thereby to generate third radiation via a second nonlinear process; at least one detector configured to measure at least one characteristic of the third radiation; and a processing unit operable to determine the at least one characteristic of the first radiation and/or the at least one characteristic of the second radiation based on said at least one characteristic of the third radiation.

Abstract: Disclosed is a method of correcting a measured spectrum for the effects of a source spectrum resulting from an illumination source. The method comprises obtaining a measured spectrum in terms of a measurement parameter, the measured spectrum being obtained from captured diffracted radiation from a periodic structure following illumination of said periodic structure using source radiation from said illumination source, the periodic structure being the spectrometer grating and an object being measured; determining an estimate of the source spectrum from the measured spectrum; and correcting the measured spectrum using the estimate of the source spectrum.

Abstract: An assembly comprises a space configured for placing a medium to receive a first radiation for generating a second radiation. In operation, the second radiation propagates coaxially with the first radiation after the medium. The assembly further comprises an optical element after the medium for transmitting or reflecting the first radiation with a surface area. The assembly is configured such that, in operation, a cleaning gas is in contact with the surface area. A reactive medium is generated from at least a part of the cleaning gas by the second radiation for removing a contamination from the surface area.

Abstract: Disclosed is a method for measuring a target located on a substrate beneath at least one layer. The method comprises exciting said at least one layer with pump radiation comprising at least one pump wavelength, so as to generate an acoustic wave within said at least one layer which reflects of said target thereby generating an acoustic replica of said target at a surface of said substrate and illuminating said acoustic replica with probe radiation comprising at least one probe wavelength and capturing the resultant scattered probe radiation, scattered from the acoustic replica. One or both of said exciting step and said illuminating step comprises generating Surface Plasmon Polaritons (SPPs) on residual topography of said at least one layer resultant from said target.

Abstract: An assembly and method for separating first radiation and second radiation in the far field, wherein the first radiation and the second radiation have non-overlapping wavelengths, The assembly comprises a capillary structure, wherein the first radiation and the second radiation propagate coaxially along at least a portion of the capillary structure, and an optical structure configured to control the spatial distribution of the first radiation outside of the capillary structure, through interference, such that the intensity of the first radiation in the far field is reduced along an optical axis of the second radiation.

Abstract: A method for determining a characteristic of a feature in an object, the feature being disposed below a surface of the object is disclosed. The surface of the object is irradiated with a pulsed pump radiation beam so as to produce an acoustic wave in the object. The surface of the object is then irradiated with a measurement radiation beam. A portion of the measurement radiation beam scattered from the surface is received and a characteristic of the feature in the object is determined from at least a portion of the measurement radiation beam scattered from the surface within a measurement time period. A temporal intensity distribution of the pulsed pump radiation beam is selected such that in the measurement time period a signal to background ratio is greater than a signal to background ratio achieved using a single pulse of the pulsed pump radiation beam.

Abstract: As increasing numbers of layers, using increasing numbers of specific materials, are deposited on substrates, it becomes increasingly difficult to detect alignment marks accurately for, for example, applying a desired pattern onto a substrate using a lithographic apparatus, in part due to one or more of the materials used in one or more of the layers being wholly or partially opaque to the radiation used to detect alignment marks. In a first step, the substrate is illuminated with excitation radiation. In a second step, at least one effect associated with a reflected material effect scattered by a buried structure is measured. The effect may, for example, include a physical displacement of the surface of the substrate. In a third step, at least one characteristic of the structure based on the measured effect is derived.

Abstract: A method for determining a characteristic of a feature in an object, the feature being disposed below a surface of the object is disclosed. The surface of the object is irradiated with a pulsed pump radiation beam so as to produce an acoustic wave in the object. The surface of the object is then irradiated with a measurement radiation beam. A portion of the measurement radiation beam scattered from the surface is received and a characteristic of the feature in the object is determined from at least a portion of the measurement radiation beam scattered from the surface within a measurement time period. A temporal intensity distribution of the pulsed pump radiation beam is selected such that in the measurement time period a signal to background ratio is greater than a signal to background ratio achieved using a single pulse of the pulsed pump radiation beam.

Abstract: As increasing numbers of layers, using increasing numbers of specific materials, are deposited on substrates, it becomes increasingly difficult to detect alignment marks accurately for, for example, applying a desired pattern onto a substrate using a lithographic apparatus, in part due to one or more of the materials used in one or more of the layers being wholly or partially opaque to the radiation used to detect alignment marks. In a first step, the substrate is illuminated with excitation radiation. In a second step, at least one effect associated with a reflected material effect scattered by a buried structure is measured. The effect may, for example, include a physical displacement of the surface of the substrate. In a third step, at least one characteristic of the structure based on the measured effect is derived.