Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05G—X-RAY TECHNIQUE
  • H05G2/00—Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma
  • H05G2/001—Production of X-ray radiation generated from plasma
  • H05G2/003—Production of X-ray radiation generated from plasma the plasma being generated from a material in a liquid or gas state
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05G—X-RAY TECHNIQUE
  • H05G2/00—Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma
  • H05G2/001—Production of X-ray radiation generated from plasma
  • H05G2/003—Production of X-ray radiation generated from plasma the plasma being generated from a material in a liquid or gas state
  • H05G2/006—Production of X-ray radiation generated from plasma the plasma being generated from a material in a liquid or gas state details of the ejection system, e.g. constructional details of the nozzle
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05G—X-RAY TECHNIQUE
  • H05G2/00—Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma
  • H05G2/001—Production of X-ray radiation generated from plasma
  • H05G2/008—Production of X-ray radiation generated from plasma involving an energy-carrying beam in the process of plasma generation

Definitions

• the invention relates to a device for producing a droplet target, at least comprising a vessel for holding a target liquid, in which a high pressure is achieved by means of gaseous nitrogen, a magnetic valve connected to the vessel and switching in the ms range, and a nozzle, as well as a procedure.
• No. 6,324,256 also contains a device for generating droplet targets in an arrangement which describes a laser plasma source for generating EUV light.
• the droplets produced have a larger diameter than droplets which are generated from a gas which is passed through a nozzle, condenses here and forms a cloud of extremely small particles in the form of clusters.
• a liquid is first generated from a gas by means of a heat exchanger which reduces the temperature of the gas. This liquid is fed to a nozzle, the opening of which becomes larger in the direction of the outlet opening.
• the droplets are formed, which then emerge from the outlet opening of the nozzle and interact with a laser beam to generate EUV light to step.
• the droplet size cannot be set in a defined manner.
• the gaseous starting material is first converted into a liquid one.
• the droplets interact with the laser beam very close to the nozzle, which is subsequently destroyed by heating and erosion.
• High-density droplet mist with a density of up to 10 19 atoms / cm 3 and a droplet diameter of approximately 1 ⁇ m was produced using a droplet source, which is described in Rev. Sei. Instrum. 69, 3780 (1998) by LC Mountford, RA Smith and MRHR Hutchinson and from which the present invention is based.
• a solenoid valve, which forms the liquid pulse and thus the liquid volume, is the starting point of the droplet source.
• a vessel was filled with a liquid and kept under high pressure by means of ethanol. In synchronization with the laser the valve is opened for 2500 ⁇ s so that the droplets emerge from the nozzle.
• Droplets with a smaller diameter of approximately 0.6 ⁇ m could be achieved by subsequent electrostatic splitting of the droplets, which, however, requires a technically complex arrangement.
• the mist consisting of these droplets has a lower density, namely approximately 10 16 atoms / cm 3 .
• droplet targets are available which have the size of possible laser wavelengths (TD Donelly, M. Rust, I. Weiner, M. Allen, RA Smith , CA. Steinke, S. Wilks, J. Zweiack, TE Cowan and T. Ditmire J. Phys. B: At. Mol. Opt. Phys. 34, L313 (2001)) and thus a smaller one compared to the prior art Have diameter and form a nebula that has an atomic density of> 10 18 atoms / cm 3 .
• the high density should also be realized at a greater distance from the nozzle, i.e. the droplet target has better collimation compared to the prior art in order to increase the service life of the nozzle.
• the nozzle is designed as a supersonic nozzle
• the valve is connected to the supersonic nozzle via an expansion channel
• means for heating the expansion channel are designed such that the temperature can be adjusted to a size is, in which a supersaturated vapor is formed in the expansion channel
• an insulator is arranged between the electromagnetic valve and the means for heating.
• the device according to the invention enables the generation of high-density sub- ⁇ liquid targets that are used for the investigation of the Interaction processes of laser radiation with plasmas are required.
• the droplets in the solution according to the invention arise from supersaturated steam, which condenses in a cloud of fog.
• the target produced with the device according to the invention consists of droplets with an average diameter of approximately 150 nm and has an average atomic density of> 10 18 atoms / cm 3 .
• Such a target enables the investigation of hitherto unexplored states that exist between clusters (from a few atoms up to 10 6 atoms / clusters with a local density that is approximately similar to that of a solid) and solids.
• the spatial expansion of the droplets has an impact on the increased space charge limitation of hot electrons, which in turn leads to an improved coupling of the laser energy into the ions of the droplets. This makes it possible to generate a much hotter plasma and to achieve a higher efficiency in the conversion into X-rays.
• the droplet target produced with the device according to the invention can be produced continuously and has a time-unlimited mode of operation.
• Embodiments of the device according to the invention relate to the configuration of its individual components. It is provided that the pulsed electromagnetic valve operates with a pulse duration of 2 ms; the expansion channel has a length of a few mm to a few 10 mm and a diameter of a few 100 ⁇ m into the mm range, the supersonic nozzle has a conical opening angle 2 ⁇ of a few degrees to a few 10 degrees, an inlet opening of a few 100 ⁇ m in diameter and one has a few mm long conical section.
• the process according to the invention comprises the following process steps: filling a target liquid into a vessel in which a high pressure is achieved by means of non-reactive gas, briefly opening this vessel by means of a pulsed electromagnetic valve, intermittent introduction of the target liquid into an expansion channel, heating the Expansion channel in such a way that supersaturated liquid vapor forms, cooling of this vapor when passing through a supersonic nozzle connected to the expansion channel and droplets emerging from the outlet opening of the nozzle into the vacuum.
• a pulsed electromagnetic valve operating in the ms range with a pulse duration in particular of 2 ms is used.
• the target liquid is pressed into the expansion channel and the corresponding vapor into the supersonic nozzle.
• the nozzle diameter also determines the diameter of the liquid droplets which emerge from the nozzle opening into the vacuum.
• the valve in the solution according to the invention directly regulates the feed into an additionally arranged expansion channel in which the target Liquid is heated.
• the super-saturated gas now present is led to the nozzle outlet opening and cooled in the process, which causes droplet formation in the nozzle.
• the valve directly switches the nozzle on and off, as a result of which much less influence on the formation and expansion of the droplets and their collimation is possible.
• FIG. 1 shows the schematic structure of a device according to the invention
• Fig. 2 is a curve with the switching pulse of the valve and the associated
• Fig. 3 is a curve with the spread of the liquid mist in
• Air and vacuum; 4 shows a curve with the density of the liquid mist as a function of the distance from the outlet opening of the nozzle;
• the inventive device for generating a droplet target has a pulsed electromagnetic valve 1.
• This valve 1 closes a vessel (not shown) in which the target liquid is kept at a pressure of 35 bar by means of gaseous nitrogen.
• the target liquid can be water, but also in principle any other liquid.
• the valve 1 opens and closes with a pulse duration of 2 ms and releases water droplets into an expansion channel 2 with a diameter of 1 mm and a length of 15 mm in the opening phase.
• this expansion channel 2 is a temperature of 150 ° C by means of a heater 3 generated, the expansion channel 2 is separated from the valve 1 by means of an insulator 5.
• a droplet target which can be generated continuously and which enables an unlimited working time.
• Fig. 2 shows a curve with the switching pulse of the valve and the associated intensity of the resulting liquid mist as a function of time, at a distance of 1 mm from the outlet opening of the nozzle.
• the pulse duration of the valve in this measurement in which the radiation generated by a cw He-Ne laser was aimed at the droplet target, scattered there and the intensity of the scattered radiation was determined at a distance of 1 mm from the nozzle opening, was 2 ms , It can be seen that the main part of the spray pulse occurs about 1 ms after opening the valve.
• the measured droplet density varies for droplets with a diameter of 0.15 ⁇ m from (1, 6 + 0.5) 10 11 droplets / cm 3 (or an average molecular density of 1, 5-10 18 cm “3 ) directly at the Outlet opening of the nozzle up to (7.5 + 0.7) -10 9 droplets / cm 3 (or an average molecular density of 8-10 16 cm “3 ) at a distance of 20 mm from the outlet opening.
• this droplet size this is up to three orders of magnitude higher droplet density than with currently described spray droplet sources, which is important for the conversion of irradiated laser energy.
• the solid line indicates the theoretical distribution of the scattered light intensity of particles with a diameter of 0.15 ⁇ m.
• the good agreement with the measurement data shows that there is a narrower distribution of the droplet sizes than in comparison with the current state of the art, so that no droplet size filter has to be connected, as in the current state, and the effective droplet density is thus advantageously increased.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• X-Ray Techniques (AREA)
• Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
• Structure Of Belt Conveyors (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

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• 2002
  • 2002-12-13 DE DE10260376A patent/DE10260376A1/de not_active Ceased
• 2003
  • 2003-12-11 WO PCT/DE2003/004129 patent/WO2004056158A2/fr active IP Right Grant
  • 2003-12-11 US US10/538,802 patent/US7306015B2/en not_active Expired - Lifetime
  • 2003-12-11 EP EP03813077A patent/EP1574116B1/fr not_active Expired - Lifetime
  • 2003-12-11 DE DE50307397T patent/DE50307397D1/de not_active Expired - Fee Related
  • 2003-12-11 JP JP2004559610A patent/JP4488214B2/ja not_active Expired - Lifetime
  • 2003-12-11 AT AT03813077T patent/ATE363819T1/de not_active IP Right Cessation
  • 2003-12-11 AU AU2003300494A patent/AU2003300494A1/en not_active Abandoned

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