A set of tracking devices can be placed within a geographic area as part of a scavenger hunt. A user with a mobile device can traverse the area, and when the user moves within a threshold proximity or communicative range of a tracking device, the mobile device can receive a communication from the tracking device identifying the tracking device. In response to determining that the tracking device is part of the set of tracking devices and thus part of the scavenger hunt, the mobile device can modify a tracking device interface displaying a representation of the tracking device to indicate that the tracking device has been found. In response to each tracking device being found, the mobile device can modify the tracking device interface to indicate that the scavenger hunt has been completed.

Degradation of the reflectivity of one or more reflective optical elements in a system (SO) for generating EUV radiation is reduced by the controlled introduction of a gas into a vacuum chamber (26) containing the optical element. The gas may be added to the flow of another gas such as hydrogen or alternated with the introduction of hydrogen radicals.

A laser produced plasma light source comprises a vacuum chamber with a rotating target assembly supplying a target into an interaction zone with focused laser beam. The target is layer of a fluid and/or free-flowing target material on a surface of annular groove in the rotating target assembly. An output beam of short-wavelength radiation exits the interaction zone to an optical collector through the means for debris mitigation. A linear velocity of the target is not less than 100 m/s and a vector of the linear velocity of the target in the interaction zone is directed on one side of a plane passing through the interaction zone and the rotation axis while the focused laser beam and the output beam are located on another side of said plane. The optical collector comprises two ellipsoidal mirror units arranged in a tandem.

An extreme ultraviolet (EUV) light generating apparatus includes a vessel including a first end and a second end opposite to each other and providing an internal space extending from the first end to the second end, a concave mirror adjacent to the first end of the vessel, a droplet generator supplying a droplet to the internal space of the vessel, a laser light source irradiating a laser beam to cause the droplet to emit EUV light, and a gas jet receiving a flow control gas and spraying the received flow control gas into the internal space of the vessel. The gas jet includes a ring-shaped main body including nozzles spaced apart from one another in a circumferential direction. The nozzles spray the received flow control gas in a downward direction.

A set of tracking devices can be placed within a geographic area as part of a scavenger hunt. A user with a mobile device can traverse the area, and when the user moves within a threshold proximity or communicative range of a tracking device, the mobile device can receive a communication from the tracking device identifying the tracking device. In response to determining that the tracking device is part of the set of tracking devices and thus part of the scavenger hunt, the mobile device can modify a tracking device interface displaying a representation of the tracking device to indicate that the tracking device has been found. In response to each tracking device being found, the mobile device can modify the tracking device interface to indicate that the scavenger hunt has been completed.

A pellicle including: a pellicle film including a carbon-based film having a carbon content rate of 40 mass % or more; a support frame that supports the pellicle film; and an adhesive layer containing an adhesive, the pellicle having the total amount of aqueous outgas of 5.0×10.sup.−4 Pa.Math.L/sec or less in an atmosphere of 23° C. and 1×10.sup.−3 Pa or less.

A mirror, such as for a microlithographic projection exposure apparatus, comprises an optical effective surface. The mirror comprises a mirror substrate and a plurality of cavities in the mirror substrate. Fluid can be applied to each cavity. A deformation is transferable to the optical effective surface by varying the fluid pressure in the cavities. Related optical systems methods are provided.

A photolithography system utilizes tin droplets to generate extreme ultraviolet radiation for photolithography. The photolithography system irradiates the droplets with a laser. The droplets become a plasma and emit extreme ultraviolet radiation. The photolithography system senses contamination of a collector mirror by the tin droplets and adjusts the flow of a buffer fluid to reduce the contamination.

An extreme ultraviolet (EUV) lithography system includes a vane bucket module. The vane bucket module includes a temperature adjusting pack and a collecting tank inserted into the temperature adjusting pack. The temperature adjusting pack has a plurality of inlets. The collecting tank has a cover and the cover includes a plurality of through holes. The inlets of the temperature adjusting pack are aligned with the through holes of the cover. Thicknesses of edges of the cover is different from a thickness of a center of the cover.

A photolithography system utilizes tin droplets to generate extreme ultraviolet radiation for photolithography. The photolithography system irradiates the droplets with a laser. The droplets become a plasma and emit extreme ultraviolet radiation. The photolithography system senses contamination of a collector mirror by the tin droplets and adjusts the flow of a buffer fluid to reduce the contamination.