Abstract: The invention provides a method and apparatus for a commercially viable EUV light source for EUV metrology and actinic inspection of EUV lithography masks. The invention is carried out using a laser target in the form of a continuous jet of liquid Lithium, circulated in a closed loop system by means of a high temperature pump. The collector mirror is placed outside the vacuum chamber in an environment filled with an inert gas and EUV output to a collector mirror is provided through the spectral purity filter, configured as an EUV exit window for the vacuum chamber. In the vacuum chamber, the input window for the laser beam is coated with a screening optical element. Evaporative cleaning of the EUV spectral purity filter and the screening optical element is provided. The protective shield with a temperature higher than 180° C. may be adjusted around the target jet.

Abstract: The invention relates to light sources with laser pumping and to methods for generating radiation with a high luminance in the ultraviolet (UV) and visible spectral ranges. The technical result of the invention includes extending the functional possibilities of a light source with laser pumping by virtue of increasing the luminance, increasing the coefficient of absorption of the laser radiation by a plasma, and significantly reducing the numerical aperture of a divergent laser beam which is to be occluded and which is passing through the plasma. The device comprises a chamber containing a gas, a laser producing a laser beam, an optical element, a region of radiating plasma produced in the chamber by the focused laser beam, an occluder, which is mounted on the axis of the divergent laser beam on the second side of the chamber, and an optical system for collecting plasma radiation.

Abstract: Invention provides extending the functional possibilities of a light source with laser pumping due to increasing its spatial and energy stability brightness and the reliability under long-term operation whilst ensuring compactness of the device. The result is achieved due to the fact that a focused laser beam is directed into a region of radiating plasma from the bottom upwards: from the lower wall of a chamber to an upper wall of the chamber which is opposite said lower wall, and the region of radiating plasma is arranged close to the upper wall of the chamber. In embodiments of the invention, the focused laser beam is directed along a vertical axis of symmetry of the walls of the chamber, the region of radiating plasma is produced at an optimally small distance away from the upper wall of the chamber and determined radiation power is maintained via an automated control system.

Abstract: Invention provides extending the functional possibilities of a light source with laser pumping due to increasing its spatial and energy stability, brightness and the reliability under long-term operation whilst ensuring compactness of the device. The result is achieved due to the fact that a focused laser beam is directed into a region of radiating plasma from the bottom upwards: from the lower wall of a chamber to an upper wall of the chamber which is opposite said lower wall, and the region of radiating plasma is arranged close to the upper wall of the chamber. In embodiments of the invention, the focused laser beam is directed along a vertical axis of symmetry of the walls of the chamber, the region of radiating plasma is produced at an optimally small distance away from the upper wall of the chamber and predetermined radiation power is maintained via an automated control system.

Abstract: The invention relates to light sources with laser pumping and to methods for generating radiation with a high luminance in the ultraviolet (UV) and visible spectral ranges. The technical result of the invention includes extending the functional possibilities of a light source with laser pumping by virtue of increasing the luminance, increasing the coefficient of absorption of the laser radiation by a plasma, and significantly reducing the numerical aperture of a divergent laser beam which is to be occluded and which is passing through the plasma. The device comprises a chamber containing a gas, a laser producing a laser beam, an optical element, a region of radiating plasma produced in the chamber by the focused laser beam, an occluder, which is mounted on the axis of the divergent laser beam on the second side of the chamber and an optical system for collecting plasma radiation.