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 contamination prevention system is constructed and arranged to prevent material from propagating with radiation into a lithographic apparatus. The contamination prevention system includes a rotatable carrier provided with a plurality of generally radially outwardly extending blades. The blades are constructed and arranged to absorb or deflect the material. The system also includes a stationary shaft, and a bearing constructed and arranged to rotate the rotatable carrier and the blades around the shaft. The rotatable carrier is provided with a space for at least partially receiving a portion of the shaft.

Abstract: A lithographic apparatus, comprising a collector being constructed to receive radiation from a radiation source and transmit radiation to an illumination system, wherein the collector is provided with at least one fluid duct, the apparatus including a temperature conditioner to thermally condition the collector utilizing the fluid duct of the collector, the temperature conditioner being configured to feed a first fluid to the fluid duct during a first period, and to feed a second fluid to the fluid duct during at least a second period.

Abstract: A collector assembly with a radiation collector, a cover plate and a support member connecting the radiation collector to the cover plate are provided. The cover plate is designed to cover an opening in a collector chamber. The collector chamber opening may be large enough to pass the radiation collector and the support member. The removed radiation collector can be cleaned with different cleaning procedures, which may be performed in a cleaning device. Such cleaning device may for example consist of the following: a circumferential hull designed to provide an enclosure volume for circumferentially enclosing at least the radiation collector; an inlet configured to provide at least one of a cleaning gas and a cleaning liquid to the enclosure volume to clean at least said radiation collector; and an outlet configured to remove said at least one of said cleaning gas and said cleaning liquid from the enclosure volume.

Abstract: The invention pertains to a measurement system for measuring displacement of a moveable object relative to a base in at least a first direction of measurement, the moveable object having at least one reference part that is moveable in a plane of movement relative to the base, the actual movements of the reference part being within an area of said plane of movement that is bounded by a closed contour having a shape. The measurement system comprises a sensor head that operatively communicates with a planar element. The sensor head is mounted onto the base and the planar element being mounted onto the reference part of the moveable object or the other way around, wherein the planar element has a shape that is essentially identical to the shape of the closed contour.