Methods and systems for generating X-ray illumination from a laser produced plasma (LPP) employing a liquid sheet jet target are presented herein. A highly focused, short duration laser pulse is directed to a liquid sheet jet target. The interaction of the focused laser pulse with the sheet jet target ignites a plasma. In some embodiments, the liquid sheet jet is generated by a convergent capillary nozzle or a convergent, planar cavity nozzle. In some embodiments, the target material includes one or more elements having a relatively low atomic number. In some embodiments, the liquid sheet jet LPP light source generates multiple line or broadband X-ray illumination in a soft X-ray (SXR) spectral range used to measure structural and material characteristics of semiconductor structures. In some embodiments, Reflective, Small-Angle X-ray Scatterometry measurements are performed with a liquid sheet jet LPP illumination source as described herein.

An extreme ultraviolet light generating system may include: a chamber; a target feeding unit configured to feed a target into the chamber; a drive laser unit configured to irradiate the target with a drive pulsed laser light beam to generate a plasma to thereby generate extreme ultraviolet light; a probe laser unit configured to irradiate the plasma with a probe pulsed laser light beam to thereby generate Thomson scattered light; a spectrometer configured to measure a spectrum waveform of an ionic term in the Thomson scattered light; and a wavelength filter disposed upstream of the spectrometer, and configured to suppress light with a predetermined wavelength from entering the spectrometer. The light with the predetermined wavelength may be part of light containing the Thomson scattered light, and the predetermined wavelength may be substantially same as a wavelength of the probe pulsed laser light beam.

A target supply device according to a first aspect of the present disclosure is configured to supply a metal target in a plasma generation region and may include a tank configured to house the metal target, a filter having been subjected to a dehydration process, the filter being configured to suppress passage of particles in the metal target housed in the tank, and a nozzle provided with a nozzle hole configured to eject the metal target that has passed through the filter.

A beam delivery system may include: beam adjusters configured to adjust a divergence angle of a pulse laser beam; a beam sampler configured to separate a part of the pulse laser beam outputted from a first beam adjuster provided at the most downstream among the beam adjusters to acquire a sample beam; a beam monitor configured to receive the sample beam and output a monitored diameter; and a beam delivery controller configured to control the beam adjusters based on the monitored diameter. The beam delivery controller may adjust each of beam adjusters other than the first beam adjuster selected one after another from the most upstream so that the monitored diameter at the beam monitor becomes a predetermined value specific to the beam adjuster, and adjust the first beam adjuster so that the pulse laser beam becomes focused at a position downstream of a target position.

A light source with radiating plasma sustained in the gas-filled chamber by a focused beam of CW laser. The gas is inert gas with a purity of at least 99.99%. The chamber contains a metal housing with at least one window made of MgF.sub.2 for outputting a plasma radiation. Each window is located in a hole of the housing on the end of a sleeve and is soldered to the sleeve by means of glass cement, and each sleeve is welded to the hole of the metal housing on the outside seam. The sleeves and the housing are made of an alloy with a coefficient of linear thermal expansion (CLTE), matched with the CLTE of the MgF.sub.2 crystal in the direction perpendicular to the optical axis of the MgF.sub.2 crystal. The technical result consists in expanding the radiation spectrum of the light source into the VUV region.

A method and apparatus for control of a dose of extreme ultraviolet (EUV) radiation generated by a laser produced plasma (LPP) EUV light source that combines pulse control mode and pulse modulation. The EUV energy created by each pulse is measured and total EUV energy created by the fired pulses determined, a desired energy for the next pulse is determined based upon whether the total EUV energy is greater or less than a desired average EUV energy times the number of pulses. If the desired pulse energy for the next droplet is within the range of one or more pulse modulation actuators, the pulse is modulated; otherwise, the pulse is fired to miss the droplet. This provides greater control of the accumulated dose as well as uniformity of the EUV energy over time, greater ability to compensate for pulses that generate EUV energy that is higher or lower than nominal expected values, and ability to provide an average EUV energy per pulse that is less than the nominal minimum EUV energy per pulse of the system.

A beam adjusting apparatus of an extreme ultraviolet light generating apparatus may include: a first pair of mirrors constituted by a first concave mirror and a first convex mirror, provided along the optical path of the pulsed laser beam; a second pair of mirrors constituted by a second concave mirror and a second convex mirror, which are arranged in an order reversed from the order of arrangement of the first concave mirror and the first convex mirror, provided along the optical path of the pulsed laser beam downstream from the first pair of mirrors; and a moving apparatus configured to simultaneously increase or simultaneously decrease the distance between the first concave mirror and the first convex mirror and the distance between the second concave mirror and the second convex mirror.

A beam adjusting apparatus of an extreme ultraviolet light generating apparatus may include: a first pair of mirrors constituted by a first concave mirror and a first convex mirror, provided along the optical path of the pulsed laser beam; a second pair of mirrors constituted by a second concave mirror and a second convex mirror, which are arranged in an order reversed from the order of arrangement of the first concave mirror and the first convex mirror, provided along the optical path of the pulsed laser beam downstream from the first pair of mirrors; and a moving apparatus configured to simultaneously increase or simultaneously decrease the distance between the first concave mirror and the first convex mirror and the distance between the second concave mirror and the second convex mirror.

A deoxidation system for purifying target material for an EUV light source includes a furnace having a central region and a heater for heating the central region in a uniform manner. A vessel is inserted in the central region of the furnace, and a crucible is disposed within the vessel. A closure device covers an open end of the vessel to form a seal having vacuum and pressure capability. The system also includes a gas input tube, a gas exhaust tube, and a vacuum port. A gas supply network is coupled in flow communication with an end of the gas input tube and a gas supply network is coupled in flow communication with an end of the gas exhaust tube. A vacuum network is coupled in flow communication with one end of the vacuum port. A method and apparatus for purifying target material also are described.

High-contrast, subtraction, x-ray images of an object are produced via scanned illumination by a laser-Compton x-ray source. The spectral-angle correlation of the laser-Compton scattering process and a specially designed aperture and/or detector are utilized to produce/record a narrow beam of x-rays whose spectral content consists of an on-axis region of high-energy x-rays surrounded by a region of slightly lower-energy x-rays. The end point energy of the laser-Compton source is set so that the high-energy x-ray region contains photons that are above the k-shell absorption edge (k-edge) of a specific contrast agent or specific material within the object to be imaged while the outer region consists of photons whose energy is below the k-edge of the same contrast agent or specific material. Scanning the illumination and of the object by this beam will simultaneously record and map the above edge and below k-edge absorption response of the object.