Abstract: A radiation sensor apparatus for determining a position and/or power of a radiation beam, the radiation sensor apparatus including a chamber to contain a gas, one or more sensors, and a processor. The chamber has a first opening and a second opening such that a radiation beam can enter the chamber through the first opening, propagate through the chamber generally along an axis, and exit the chamber through the second opening. Each of the one or more sensors is arranged to receive and detect radiation emitted from a region of the chamber around the axis. The processor is operable to use the radiation detected by the one or more sensors to determine a position and/or power of the radiation beam.

Abstract: A target structure (T) made by lithography or used in lithography is inspected by irradiating the structure at least a first time with EUV radiation (304) generated by inverse Compton scattering. Radiation (308) scattered by the target structure in reflection or transmission is detected (312) and properties of the target structure are calculated by a processor (340) based on the detected scattered radiation. The radiation may have a first wavelength in the EUV range of 0.1 nm to 125 nm. Using the same source and controlling an electron energy, the structure may be irradiated multiple times with different wavelengths within the EUV range, and/or with shorter (x-ray) wavelengths and/or with longer (UV, visible) wavelengths. By rapid switching of electron energy in the inverse Compton scattering source, irradiation at different wavelengths can be performed several times per second.

Abstract: Methods and apparatus for generation of radiation by high harmonic generation, HHG. The apparatus comprises: a chamber for holding a vacuum, the chamber comprising a radiation input, a radiation output and an interaction region at which, in use, a medium is present, the chamber being arranged such that, in use, when driving radiation propagates through the radiation input and is incident upon the medium, the medium emits radiation via HHG, the emitted radiation propagating through the radiation output; and at least one plasma generator at the radiation input and/or the radiation output for generating a plasma volume allowing the driving radiation and emitted radiation, respectively, to propagate through the plasma volume.

Abstract: A target structure (T) made by lithography or used in lithography is inspected by irradiating the structure at least a first time with EUV radiation (304) generated by inverse Compton scattering. Radiation (308) scattered by the target structure in reflection or transmission is detected (312) and properties of the target structure are calculated by a processor (340) based on the detected scattered radiation. The radiation may have a first wavelength in the EUV range of 0.1 nm to 125 nm. Using the same source and controlling an electron energy, the structure may be irradiated multiple times with different wavelengths within the EUV range, and/or with shorter (x-ray) wavelengths and/or with longer (UV, visible) wavelengths. By rapid switching of electron energy in the inverse Compton scattering source, irradiation at different wavelengths can be performed several times per second.

Abstract: A membrane transmissive to EUV radiation, which may be used as a pellicle or spectral filter in a lithographic apparatus. The membrane has one or more high doped regions wherein the membrane is doped with a dopant concentration greater than 1017 cm?3, and one or more regions with low (or no) doping. The membrane may have a main substrate having low doping and one or more additional layers, wherein the high doped regions are within some or all of the additional layers.

Abstract: A membrane transmissive to EUV radiation, which may be used as a pellicle or spectral filter in a lithographic apparatus. The membrane includes one or more high doped regions wherein the membrane is doped with a dopant concentration greater than 1017 cm?3, and one or more regions with low (or no) doping. The membrane may have a main substrate having low doping and one or more additional layers, wherein the high doped regions are comprised within some or all of the additional layers.

Abstract: Methods and apparatus for generation of radiation by high harmonic generation, HHG. The apparatus comprises: a chamber for holding a vacuum, the chamber comprising a radiation input, a radiation output and an interaction region at which, in use, a medium is present, the chamber being arranged such that, in use, when driving radiation propagates through the radiation input and is incident upon the medium, the medium emits radiation via HHG, the emitted radiation propagating through the radiation output; and at least one plasma generator at the radiation input and/or the radiation output for generating a plasma volume allowing the driving radiation and emitted radiation, respectively, to propagate through the plasma volume.

Abstract: A photocathode comprises a substrate in which a cavity is formed and a film of material disposed on the substrate. The film of material comprises an electron emitting surface configured to emit electrons when illuminated by a beam of radiation. The electron emitting surface is on an opposite side of the film of material from the cavity.

Abstract: A pellicle that includes graphene is constructed and arranged for an EUV reticle. A multilayer mirror includes graphene as an outermost layer.

Abstract: Disclosed is a suppression filter having a profile defining at least two reflective surface levels, each reflected surface level being separated by a separation distance. The separation distance is such that the reflective suppression filter is operable to substantially prevent specular reflection of radiation at a first wavelength and at a second wavelength incident on said reflective suppression filter. Also disclosed is a radiation collector, radiation source and lithographic apparatus comprising such a suppression filter, and to a method of determining a separation distance between at least two reflective surface levels of a suppression filter.

Abstract: A target structure (T) made by lithography or used in lithography is inspected by irradiating the structure at least a first time with EUV radiation (304) generated by inverse Compton scattering. Radiation (308) scattered by the target structure in reflection or transmission is detected (312) and properties of the target structure are calculated by a processor (340) based on the detected scattered radiation. The radiation may have a first wavelength in the EUV range of 0.1 nm to 125 nm. Using the same source and controlling an electron energy, the structure may be irradiated multiple times with different wavelengths within the EUV range, and/or with shorter (x-ray) wavelengths and/or with longer (UV, visible) wavelengths. By rapid switching of electron energy in the inverse Compton scattering source, irradiation at different wavelengths can be performed several times per second.

Abstract: A radiation source for a lithographic apparatus uses a plurality of fiber lasers to ignite a fuel droplet at an ignition location to generate EUV radiation. The fiber lasers may be provided to emit parallel to an optical axis and a telescopic optical system is provided to focus the lasers at the ignition location, or the lasers may be directed towards the optical axis with a final focus lens being used to reduce beam waist. The lasers may be provided in two or more groups to allow them to be independently controlled and some of the lasers may be focused at a different location to provide a pre-pulse. Radiation from fiber lasers may also be combined using dichroic mirrors.

Abstract: A lithographic apparatus for patterning a beam of radiation and projecting it onto a substrate, comprising at least two spectral purity filters configured to reduce the intensity of radiation in the beam of radiation in at least one undesirable range of radiation wavelength, wherein the two spectral purity filters are provided with different radiation filtering structures from each other.

Abstract: A pellicle that includes graphene is constructed and arranged for an EUV reticle. A multilayer mirror includes graphene as an outermost layer.

Abstract: A method of generating radiation for a lithography apparatus. The method comprises providing a continuously renewing fuel target (50) at a plasma formation location (12) and directing a continuous-wave excitation beam (6) at the plasma formation location such that fuel within the continuously renewing fuel target is excited by the continuous-wave excitation beam to a radiation generating plasma.

Abstract: A lithographic apparatus and device manufacturing method makes use of a liquid confined in a reservoir between the projection system and the substrate. Bubbles forming in the liquid from dissolved atmospheric gases or from out-gassing from apparatus elements exposed to the liquid are detected and/or removed so that they do not interfere with exposure and lead to printing defects on the substrate. Detection may be carried out by measuring the frequency dependence of ultrasonic attenuation in the liquid and bubble removal may be implemented by degassing and pressurizing the liquid, isolating the liquid from the atmosphere, using liquids of low surface tension, providing a continuous flow of liquid through the imaging field, and/or phase shifting ultrasonic standing-wave node patterns.

Abstract: An imprint lithography apparatus is disclosed which includes a pattern fixing system configured to use actinic radiation to fix a pattern provided in a layer of imprintable medium by an imprint lithography template, and an inspection system configured to use inspection radiation to inspect an element constituting or, in use, being located within, the imprint lithography apparatus. The imprint lithography apparatus is configured such that the pattern fixing system and the inspection system are provided, in use, with, respectively, actinic radiation and inspection radiation from a single source of radiation.

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: A radiation sensor apparatus for determining a position and/or power of a radiation beam, the radiation sensor apparatus including a chamber to contain a gas, one or more sensors, and a processor. The chamber has a first opening and a second opening such that a radiation beam can enter the chamber through the first opening, propagate through the chamber generally along an axis, and exit the chamber through the second opening. Each of the one or more sensors is arranged to receive and detect radiation emitted from a region of the chamber around the axis. The processor is operable to use the radiation detected by the one or more sensors to determine a position and/or power of the radiation beam.

Abstract: A lithographic apparatus includes an optical element that includes an oriented carbon nanotube sheet. The optical element has an element thickness in the range of about 20-500 nm and has a transmission for EUV radiation having a wavelength in the range of about 1-20 nm of at least about 20% under perpendicular irradiation with the EUV radiation.