Abstract: A radiation source generates short-wavelength radiation, such as extreme ultraviolet radiation, for use in lithography. Rotating electrodes are provided which dip into respective baths of liquid metal, for example, tin. An electrical discharge is produced between the electrodes to generate the radiation. Holes are provided in the electrodes and/or in a metal shielding plate around the electrodes to enable better pumping down to low pressure in the vicinity of the discharge to improve the conversion efficiency of the source. The holes in the electrodes improve cooling of the electrodes by causing stirring of the liquid metal, and by improving the thermal and electrical contact between the electrodes and the liquid metal. Improved electrical contact also reduces the time-constant of the discharge circuit, thereby further improving the conversion efficiency of the source.

Abstract: A device for generating radiation source based on a discharge includes a cathode and an anode. A discharge is created in a material comprising an alloy of two or more substances.

Abstract: A method for cleaning elements of a lithographic apparatus, for example optical elements such as a collector mirror, includes providing a gas containing nitrogen; generating nitrogen radicals from at least part of the gas, thereby forming a radical containing gas; and providing at least part of the radical containing gas to the one or more elements of the apparatus. A lithographic apparatus includes a source and an optical element, and an electrical discharge generator arranged to generate a radio frequency discharge.

Abstract: A foil trap is located in a path of a radiation beam. The foil trap includes an array of conductive strips. A voltage application circuit is coupled to the strips to apply voltage differences between pairs of adjacent ones of the strips. The voltage application circuit includes a current limiting circuit arranged to limit currents to the strips to values below a threshold value above which self-sustained arc discharge may arise in the foil trap.

Abstract: A lithographic apparatus is arranged to project a beam from a radiation source onto a substrate. The apparatus includes an optical element in a path of the beam, a gas inlet for introducing a gas into the path of the beam so that the gas will be ionized by the beam to create electric fields toward the optical element, and a gas source coupled to the gas inlet for supplying the gas. The gas has a threshold of kinetic energy for sputtering the optical element that is greater than the kinetic energy developed by ions of the gas in the electric fields.

Abstract: A device for generating radiation or a source based on a discharge includes a cathode and an anode. The cathode and anode material are supplied in fluid state. The material forms a plasma pinch when the device is in use. Optionally, nozzles may be used to supply the material. The cathode and/or anode may form a flat surface. The trajectories of the material may be elongated. A laser may be used to cause the discharge more easily. The laser may be directed on the anode of cathode or on a separate material located in between the anode and cathode.

Abstract: A device for generating radiation source based on a discharge includes a cathode and an anode. The cathode and anode material are supplied in fluid state. The material forms a plasma pinch when the device is in use. Optionally, nozzles may be used to supply the material. The cathode and/or anode may form a flat surface. The trajectories of the material may be elongated. A laser may be used to cause the discharge more easily. The laser may be directed on the anode of cathode or on a separate material located in between the anode and cathode.

Abstract: A radiation source unit is provided that includes an anode and a cathode that are configured and arranged to create a discharge in a substance in a space between said anode and cathode and to form a plasma so as to generate electromagnetic radiation. The substance may comprise xenon, indium, lithium, tin or any suitable material. To improve conversion efficiency, the source unit may be constructed to have a low inductance, and operated with a minimum of plasma. To, for example, improve heat dissipation, a fluid circulation system can be created within the source volume and a wick by using a fluid in both its vapor and liquid states. To, for example, prevent contamination from entering a lithographic projection apparatus, the source unit can be constructed to minimize the production of contamination, and a trap can be employed to capture the contamination without interfering with the emitted radiation.

Abstract: A lithographic apparatus is disclosed. The lithographic apparatus includes an illumination system that provides a beam of radiation, and a support structure that supports a patterning structure. The patterning structure is configured to impart the beam of radiation with a pattern in its cross-section. The apparatus also includes a substrate support that supports a substrate, and a projection system that projects the patterned beam onto a target portion of the substrate. The illumination system includes a radiation-production system that produces extreme ultra-violet radiation, and a radiation-collection system that collects extreme ultra-violet radiation. Particles that are produced as a by-product of extreme ultra-violet radiation production move substantially in a particle-movement direction. The radiation-collection system is arranged to collect extreme ultra-violet radiation which radiates in a collection-direction, which is substantially different from the particle-movement direction.

Abstract: A lithographic projection apparatus is provided. The apparatus includes a radiation system for providing a beam of radiation, and a support for supporting a patterning device. The patterning device serves to pattern the beam of radiation according to a desired pattern. The apparatus also includes a substrate table for holding a substrate, a projection system for projecting the patterned beam of radiation onto a target portion of the substrate, and a particle supply unit for supplying getter particles into the beam of radiation in order to act as a getter for contamination particles in the beam of radiation. The getter particles have a diameter of at least about 1 nm.