Abstract: For a working wavelength in the range from 1 nm to 12 nm, a reflective optical element has, on a substrate, a multilayer system that includes at least two alternating materials having a different real part of the refractive index at the working wavelength. The multilayer system includes a first alternating material from the group formed from thorium, uranium, barium, nitrides thereof, carbides thereof, borides thereof, lanthanum carbide, lanthanum nitride, lanthanum boride, and a second alternating material from the group formed from carbon, boron, boron carbide, or lanthanum as first alternating material and carbon or boron as second alternating material. It has, on the side of the multilayer system remote from the substrate, a protective layer system including a nitride, an oxide and/or a platinum metal.

Abstract: For a working wavelength in the range from 1 nm to 12 nm, a reflective optical element has, on a substrate, a multilayer system that includes at least two alternating materials having a different real part of the refractive index at the working wavelength. The multilayer system includes a first alternating material from the group formed from thorium, uranium, barium, nitrides thereof, carbides thereof, borides thereof, lanthanum carbide, lanthanum nitride, lanthanum boride, and a second alternating material from the group formed from carbon, boron, boron carbide, or lanthanum as first alternating material and carbon or boron as second alternating material. It has, on the side of the multilayer system remote from the substrate, a protective layer system including a nitride, an oxide and/or a platinum metal.

Abstract: A source-collector device includes a target unit having a target surface of plasma-forming material and a laser unit to generate a beam of radiation directed onto the target surface to form a plasma from said plasma-forming material. A contaminant trap is provided to reduce propagation of particulate contaminants generated by the plasma. A radiation collector includes a one or more grazing-incidence reflectors arranged to collect radiation emitted by the plasma and form a beam therefrom, and a filter is configured to attenuate at least one wavelength range of the beam.

Abstract: A radiation source (60) 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 (62) along a trajectory (64) towards a plasma formation location (66). The radiation source is configured to receive a first amount of radiation (68) such that the first amount of radiation is incident on a fuel droplet (62a) at the plasma formation location, and such that the first amount of radiation transfers energy into the fuel droplet to generate a modified fuel distribution (70), the modified fuel distribution having a surface.

Abstract: A spectral purity filter includes a body of material, through which a plurality of apertures extend. The apertures are arranged to suppress radiation having a first wavelength and to allow at least a portion of radiation having a second wavelength to be transmitted through the apertures. The second wavelength of radiation is shorter than the first wavelength of radiation. The body of material is formed from tungsten-molybdenum alloy or a molybdenum-rhenium alloy or a tungsten-rhenium alloy or a tungsten-molybdenum-rhenium alloy.

Abstract: A source-collector device is constructed and arranged to generate a radiation beam, The device includes a target unit constructed and arranged to present a target surface of plasma-forming material; a laser unit constructed and arranged to generate a beam of radiation directed onto the target surface so as to form a plasma from said plasma-forming material; a contaminant trap constructed and arranged to reduce propagation of particulate contaminants generated by the plasma; a radiation collector comprising a plurality of grazing-incidence reflectors arranged to collect radiation emitted by the plasma and form a beam therefrom; and a filter constructed and arranged to attenuate at least one wavelength range of the beam.

Abstract: A radiation source (60) 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 (62) along a trajectory (64) towards a plasma formation location (66). The radiation source is configured to receive a first amount of radiation (68) such that the first amount of radiation is incident on a fuel droplet (62a) at the plasma formation location, and such that the first amount of radiation transfers energy into the fuel droplet to generate a modified fuel distribution (70), the modified fuel distribution having a surface.

Abstract: A reflector includes a multi layer mirror structure configured to reflect radiation at a first wavelength, and one or more additional layers. The absorbance and refractive index at a second wavelength of the multi layer mirror structure and the one or more additional layers, and the thickness of the multi layer mirror structure and the one or more additional layers, are configured such that radiation of the second wavelength which is reflected from a surface of the reflector interferes in a destructive manner with radiation of the second wavelength which is reflected from within the reflector.

Abstract: A spectral purity filter includes a body of material, through which a plurality of apertures extend. The apertures are arranged to suppress radiation having a first wavelength and to allow at least a portion of radiation having a second wavelength to be transmitted through the apertures. The second wavelength of radiation is shorter than the first wavelength of radiation. The body of material is formed from tungsten-molybdenum alloy or a molybdenum-rhenium alloy or a tungsten-rhenium alloy or a tungsten-molybdenum-rhenium alloy.

Abstract: A multilayer mirror is configured to reflect extreme ultraviolet (EUV) radiation while absorbing a second radiation having a wavelength substantially-longer than that of the EUV radiation. The mirror includes a plurality of layer pairs stacked on a substrate. Each layer pair comprises a first layer that includes a first material, and a second layer that includes a second material. The first layer is modified to reduce its contribution to reflection of the second radiation, compared with a simple layer of the same metal having the same thickness. Modifications can include doping with a third material in or around the metal layer to reduce its electric conductivity by chemical bonding or electron trapping, and/or splitting the metal layer into sub-layers with insulating layers. The number of layers in the stack is larger than known multilayer mirrors and may be tuned to achieve a minimum in IR reflection.