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WO2009038608A2 - Optimisation de température de sources de rayons x - Google Patents

Optimisation de température de sources de rayons x Download PDF

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Publication number
WO2009038608A2
WO2009038608A2 PCT/US2008/007763 US2008007763W WO2009038608A2 WO 2009038608 A2 WO2009038608 A2 WO 2009038608A2 US 2008007763 W US2008007763 W US 2008007763W WO 2009038608 A2 WO2009038608 A2 WO 2009038608A2
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WO
WIPO (PCT)
Prior art keywords
temperature
nozzle
target
region
ray
Prior art date
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Ceased
Application number
PCT/US2008/007763
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English (en)
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WO2009038608A3 (fr
Inventor
Charles K. Rhodes
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University of Illinois at Urbana Champaign
University of Illinois System
Original Assignee
University of Illinois at Urbana Champaign
University of Illinois System
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Publication of WO2009038608A2 publication Critical patent/WO2009038608A2/fr
Publication of WO2009038608A3 publication Critical patent/WO2009038608A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H05G2/009—Auxiliary arrangements not involved in the plasma generation
    • H05G2/0092—Housing of the apparatus for producing X-rays; Environment inside the housing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S4/00—Devices using stimulated emission of electromagnetic radiation in wave ranges other than those covered by groups H01S1/00, H01S3/00 or H01S5/00, e.g. phonon masers, X-ray lasers or gamma-ray lasers

Definitions

  • DAADl 0-0 l-C-0068 awarded by the Army Research Office via the Defense Advanced Research Projects Agency (DARPA). The government has certain rights in the invention.
  • the present invention relates to the field of X-ray energy sources and, in particular, to sources including Laser amplifiers that produce Xe(L) X-ray energy.
  • High energy X-ray sources such as Laser amplifiers
  • the production of state of the art electronic devices can benefit from such sources.
  • certain technical hurdles must be overcome to attain desired goals.
  • High energy X-ray sources offer the promise of substantial improvement to photolithographic techniques used in the fabrication of silicon chips and other integrated circuits. With this process, light or other radiation from a specialized source is projected through a photomask of an electronic circuit. This produces an image of the circuit (or, more usually, a pattern of repeated copies of the image) on the semiconductor wafer. After exposure, the wafer is coated with a light-sensitive photoresist.
  • synchrotron sources have been used for research in this operating regime. However, these sources are very large and expensive. Smaller, more economical sources are needed to fuel continued economic growth. Moreover, it is desirable to increase x-ray amplifier emission of coherent X-ray sources. Additionally, a need exists for reliably producing amplification (i.e., gain) of X-ray sources in a controllable manner.
  • the invention provides an apparatus and method for the temperature enhancement of an X-ray source to increase gain and efficiency of the radiation source, and to minimize the disadvantages associated with the prior art systems and provide advantages in construction, mode of operation and use.
  • One embodiment of the X-ray source has a Xe target gas input and produces therefrom a Xe(L) X-ray laser emission.
  • a system for providing the temperature improvement comprises a gas input system for enhancing the density and collisional interactions that enable the Xe clusters to be formed.
  • the gas input system comprises a temperature control system at the target gas input to control of the temperature of the region in which the Xe gas cluster medium is found and the amplification develops.
  • the gas input system comprises a temperature control system having a cooling stage at the amplifier gas input for cooling the Xe target gas.
  • the invention provides a method for the temperature enhancement of an X-ray source to increase gain and efficiency.
  • the X-ray source has a Xe target gas input and produces therefrom a Xe(L) X- ray laser emission.
  • the method comprises controlling the temperature of the region in which the Xe gas cluster medium is found and the amplification develops.
  • the step of controlling the temperature comprises cooling the gas input of the source.
  • FIG. 1 is a schematic diagram of a signal representing saturated amplification detected from a plasma channel
  • FIGS. 2(a)-2(d) are schematic diagrams of data showing temperature dependence of Xe(L) X-ray pulse intensity
  • FIG. 3 is a schematic diagram showing temperature dependence of Xe(L) X-ray emission intensity
  • FIG. 4(a) is a perspective view of an apparatus for enhancing an X-ray source to increase gain and efficiency according to principles of the invention
  • FIG. 4(b) is an elevated side view of an apparatus for enhancing an X- ray source to increase gain and efficiency according to principles of the invention
  • FIGS. 5a-5d are schematic diagrams illustrating improved operation of the X-ray amplifier of FIGs. 4(a) - 4(b).
  • the invention includes an apparatus and method for generating ultrabright multikilovolt coherent X-ray radiation.
  • Physical evidence is provided herein and includes the strong enhancement of selected spectral components of Xenon (i.e., Xe 35+ and Xe 37+ ) hollow atom transition arrays radiated axially from confined and enlarged plasma channels.
  • measurements of line narrowing that is spectrally correlated with the amplified transitions demonstrate amplification of multikilovolt X-rays for wavelengths between ⁇ 2.7 IA and ⁇ 2.93A.
  • energy producing equipment embodying the present invention is described herein in its usual assembled position as shown in the accompanying drawings, and terms such as upper, lower, horizontal, longitudinal, etc., may be used herein with reference to this usual position.
  • the energy conversion equipment may be manufactured, transported, sold or used in orientations other than as described and shown herein.
  • the present invention provides an improved operation of X-ray radiation sources suitable, for example, in the semiconductor fabrication industry.
  • Generation of ultrabright, multikilovolt coherent X-ray radiation resulting from amplification on hollow atom transition arrays is known and described in U.S. Patent Number 7,016,390, which is incorporated by reference herein.
  • the present invention provides an improvement in the ability to produce and stably combine two new highly ordered forms of excited matter, hollow atoms and stable electronically hollow plasma channels.
  • Hollow atoms refers to atoms (ions) that have an inverted electronic configuration and include one or more deeply bound inner-shell vacancies with the simultaneous retention of several electrons in relatively weakly bound outer orbitals. Such electronic states of the atoms facilitate prompt emission and amplification of X-rays.
  • optical projection lithography which has been used for high volume integrated circuit manufacture, is useful for patterning line widths as small as a fraction (e.g., 1 A) of a micron.
  • a fraction e.g. 1 A
  • the feature size of semiconductors decreases about 25 to 30 percent every other year, and therefore, new technologies will be required in the near future if circuit lines as small as 50 nanometers are to be realized.
  • the present invention improves operation of X-ray sources that make practical lithography possible for mass semiconductor production.
  • advanced energy sources such as a Xe(L) X-ray laser radiation source operating at ⁇ ⁇ 2.9 A have well documented [1-6] properties.
  • This source is characterized by advanced coherent X-ray emissions made possible by the ability to controllably compress power to robust values that fall at or above the highest thermonuclear range ( ⁇ 10 20 W/cm 3 ).
  • thermonuclear range ⁇ 10 20 W/cm 3
  • such systems have been demonstrated to operate with saturated amplification in the multikilovolt ( ⁇ 4230-4570 eV) X-ray range on several Xe(L) transition arrays.
  • the brightness of the source is estimated to be in the 10 31 -10 32 ⁇ -s ⁇ l -mrrf 2 -mr ⁇ 2 (0.1% Bandwidth) "1 range.
  • the findings described herein demonstrate that the emission, and consequently the amplification, can be sharply enhanced in a cost effective manner. This enhancement is provided by control of the temperature of the region in which the Xe gas cluster medium is found and the amplification develops.
  • the basic dynamic variables governing the compressible flow of a given material are the temperature (T/°C), preferably ranging between about 25°C and about -80°C, the pressure (P/bar), preferably ranging between about 1 and about 10 and the density
  • FIGS. 2(a) - 2(d) illustrate the enhancement in both the strength of the X-ray emission and the length of the amplifying channel that occurs when the Xe nozzle temperature is reduced.
  • FIGS. 2(a) - 2(d) show experimental data including (1) an enhanced signal strength and (2) the formation of longer amplifying channels, that result from cooling the Xe gas in the nozzle flow of the Xe(L) laser.
  • the incident energy of the 248 nm pulse was 410 mJ and the observed channel length was E ⁇ 1.7 mm.
  • the incident 248 nm pulse was 400 mJ.
  • a strongly enhanced spectrum and lengthened laser channel (C ⁇ 2.25 mm) are evident.
  • the system 10 includes an apparatus 12 for forming densely packed Xe clusters that form a target (not shown).
  • the apparatus 12 includes Xe input lines 14 that supply Xe gas to be formed into Xe clusters that are used as targets.
  • the Xe clusters enable the creation of Xe hollow atom states.
  • the Xe passes through the input lines 14 and into a cylindrically-shaped nozzle 16 having a nozzle aperture 18 at an outlet end 20.
  • the Xe clusters are released from the nozzle aperture 18 as discrete units of media by solenoid actuators 22 located between the target gas input line 14 and nozzle 16.
  • a control 24 operates the solenoid actuators 22, and is connected to the actuator via lead lines 26 (one connection is shown in FIG. 4(b) for simplicity).
  • the solenoid actuators 22 can be pulsed to provide units of Xe gas to the nozzle 16.
  • the control 24 operates (i.e., opens and closes) the solenoid actuators 22.
  • the nozzle 16 is configured to receive the target from an inlet end 28 and expel the target as atomic clusters from the outlet end 20.
  • the channel is produced when the pondermotive potential pushes the free electrons out of the most intense part of the laser beam creating a positive index gradient at the beam center which augments the index gradient due to the relativistic mass increase of the electrons.
  • the X-ray laser delivers a light pulse, having an energy of about 400mj at a rate of 0.4Hz, and a temporal duration of about 230fs.
  • the X-ray laser radiation is focused into the Xe clusters resulting in the release of X-ray and other electromagnetic radiation from the Xe clusters.
  • Xe clusters other materials can be used as a target such as Sulfur hexafluoride (SF 6 ), Tungsten hexafluoride (WF 6 ), and Uranium hexafluoride (UF 6 ).
  • SF 6 Sulfur hexafluoride
  • WF 6 Tungsten hexafluoride
  • U 6 Uranium hexafluoride
  • it is contemplated that other heavy elements/molecules having an atomic number Z greater than or equal to 50 can be used as targets.
  • the nozzle 16 is formed in a cylindrical shape, however it is envisioned that the nozzle can be formed in other geometrical shapes depending on the desired application. Additionally, it is desirable that the nozzle 16 is formed of a heat conducting material, for example a metal, to facilitate heat transfer as discussed below.
  • the system 10 further includes an X-ray emission source, such as an X- ray laser amplifier or laser 30.
  • the laser produces a Xe(L) X-ray ( ⁇ ⁇ 2.9 A) laser emission when interacting with a Xe target.
  • the laser 30 is provided in a generally horizontal direction as viewed in the drawing such that the laser directs a laser beam or beams (not shown) horizontally above the nozzle aperture 18.
  • the nozzle aperture 18 is configured to release the Xe gas target as densely packed Xe clusters which the laser beams propagate there through.
  • the nozzle aperture 18 is about 1.5 mm in width, although other widths are contemplated depending on the intended power output of the system 10.
  • the Xe clusters are released from the nozzle aperture 18 in response to actuation of four solenoid actuators 22 that are located upstream of the nozzle packed Xe clusters and actuated in step with the laser beam from the laser 30.
  • the solenoid actuators 22 can operate to open and release densely packed Xe clusters prior to the laser 30 emitting a laser beam above the nozzle aperture 18. While four solenoid actuators are used with the present embodiment, it is contemplated that one or more solenoid actuators or other valve members can be used to provide the target to the nozzle 16.
  • the apparatus 12 a lso includes a temperature controlled fluid input system, designated generally as 32, which includes a coolant coil 34 having a coolant input 36 and a coolant output 38.
  • the coolant input 36 connects to a source (not shown) which provides a coolant fluid to the temperature controlled fluid input system 32.
  • a gas flows through the coolant coil 34 to cool the nozzle 16.
  • the cooled nozzle 16 cools the target and enhances the collisional interactions in the target to increase the size and density of the atomic clusters formed in the nozzle.
  • other fluids having different temperature characteristics may be either singly or in combination passed through the coolant coil to achieve specified temperatures in the range of 150K to less than 297K depending upon a particular application.
  • a fluid can be either a liquid or gas.
  • a central section 40 of the coolant coil 34 encircles the nozzle 16 and is secured against the nozzle by clamp members 42.
  • the clamp members 42 are each configured to receive a fastener 44 therethrough which secures each clamp member to the nozzle 16.
  • the clamp members 42 can be formed with arcuate portions 46 that maintain the central section 40 of the coolant coil 34 in a fixed position such that the coolant coil remains in contact with the nozzle 16.
  • the present embodiments has four clamp members 34 (two shown), however it is contemplated that more or less than four clamp members could be used to secure the coolant coil 34 to the nozzle 16.
  • the coolant coil 34 could be shaped to be in close proximity to or partially contacting the nozzle 16 depending on the selected material forming the coolant coil while still providing cooling to the nozzle.
  • the central section 40 is in direct contact with the nozzle 16 to facilitate heat transfer (i.e., cooling of the nozzle).
  • the coolant coil 34 is formed of a material that facilitates transfer of heat from gases or fluids flowing through the coolant coil in the temperature range of 80K to less than 297K.
  • the coolant coil 34 encircles the nozzle 16 twice and has a nitrogen gas (N 2 ) flowing therethrough.
  • N 2 nitrogen gas
  • other cooling gases/liquids may also be used to cool the nozzle and control the temperature of the nozzle in the range between 80K and less than 297K.
  • the coolant coil 34 is positioned to encircle the nozzle 16, other configurations are possible as long as cooling is provided between the nozzle and the coolant coil.
  • the coolant coil 34 is positioned in the nozzle region, other embodiments can position the coolant coil upstream of the nozzle 16 as long as the temperature of the Xe cluster can be controlled. For example, it is envisioned that at least some enhancement of the gain and efficiency of an X-ray source would occur if the cooling coil is provided to a line (not shown) feeding Xe to the solenoid actuators 22.
  • An advantage of cooling the nozzle 16 in this manner is that the Xe clusters exiting the nozzle aperture 18 are more densely packed resulting in improved amplification of the laser beam (i.e., improved gain and efficiency).
  • the cooling fluid which includes gases and/or liquids is confined within the coolant coil 34 it is possible to control the temperature of the nozzle more precisely than conventional systems which have no temperature control.
  • the ability to easily and efficiently control the temperature allows for cooling of the nozzle 16 to prescribed temperatures.
  • the present temperature controlled fluid input system allows a nozzle temperature of 230K for Xe, which results in several advantageous effects.
  • Other materials can be similarly controlled at different temperatures that maximize the above effects for those materials. It is envisioned that a different number of turns and/or the diameter of the coolant coil 34 can be used to facilitate heat transfer between the coolant coil and the nozzle as is known to those skilled in the art of cooling.
  • the coolant coil 34 is formed as a copper line, other metal lines or heat conducting materials may be used.
  • the apparatus 12 has a solenoid actuated valve 50 positioned in the coolant coil 34 between the coolant input 36 and central section 40 for regulation of cooling gas/fluid flow through the coolant coil 34.
  • the valve 50 is connected to the control 24 (connection not shown), and can be operated (i.e., opened and closed) by instructions from the control.
  • the apparatus also has a thermocouple 52 connected to the nozzle 16 via a fastener 54.
  • the thermocouple 52 is in contact with and configured to measure the temperature of the nozzle 16, and provides feedback via a pair of lead lines 56 (shown as one line) connected to the control 24 (connection not shown).
  • the control 24 uses the feedback and generates instructions to the solenoid actuated valve 50 to control the temperature of the nozzle 16. In this manner, precise control of the temperature of the nozzle 16 can advantageously be achieved by use of the present apparatus 12.
  • solenoid actuators 22, valve 50, and thermocouple 52 are connected to a single control 24, it is envisioned that multiple controls including a control for the laser 30 can be separately provided as stand alone controls or interconnected, depending on design choice.
  • solenoid actuators and a solenoid actuated valve are used in the present embodiment, any type of valve capable of controlling gas/fluid flow through the nozzle 16 and coolant coil 34 are contemplated for use with the apparatus 12.
  • the apparatus 12 of FIGs. 4(a)-4(b) produced the data shown in FIGs. 2(a) - 2(d) and FIG. 3.
  • the apparatus 12 can be economically constructed and is simple to install and operate. It is also effective and scalable to larger sizes that would be appropriate for correspondingly increased X-ray powers.
  • FIGs. 5(a) - 5(d) the illustrated data show the prominence of double-vacancy (2s2p) excitations in the cooled spectra.
  • FIG. 5(b) shows a previously recorded (film #6) spectrum showing the amplification on the Xe 37+ (2s2p) transition array [3].
  • FIG. 5(c) shows a spectral overlap of single-pulse spectrum #32x04 with that measured on film #6 from FIG.
  • FIG. 5(d) shows a corresponding laser propagation. Very good agreement is evident for the Xe 37+ (2 s2p) feature at ⁇ s 2.80 A. Other significant corresponding spectral features are also visible, for example, the strong lines at ⁇ ⁇ 2.6 A.
  • the precise overlap of the amplified feature shown on film #6 with the strong narrow signal on the single-pulse spectrum #32x04 confirms the presence of strong double-vacancy excitation in the cooled spectrum.
  • a method for generating laser radiation having increased efficiency and gain in the X-ray region of the electromagnetic spectrum can be done using the system shown in FIGs. 4(a)-4(b), and includes the following steps: generating a target in a first region; transferring the target to a second region; controlling a temperature of the second region such that the temperature of the second region is less than the first region; transferring the target to a third region; generating laser radiation of a selected intensity and size; and directing the laser radiation into the target in the third region whereby the target comprises atomic clusters having an increased average cluster size and density.
  • the method can be implemented such that the temperature of the second region is in a range of 150K to less than 297K.
  • the atomic clusters can be selected from the group consisting of Xe, SF 6 , UF 6 , and WF 6 and other heavy elements/molecules having an atomic number Z greater than or equal to 50.
  • the laser radiation can also be an X-ray laser radiation.
  • the method can also optionally include a step of measuring the temperature in the second region.
  • a step of adjusting the temperature in the second region based on the measured temperature in the second region may also be included.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Electromagnetism (AREA)
  • X-Ray Techniques (AREA)

Abstract

La présente invention concerne un appareil et un procédé pour l'optimisation de température d'une source de rayons X pour augmenter le gain et le rendement. La source de rayons X possède une cible et produit à partir de celle-ci une émission laser à rayons X. L'appareil comprend une buse configurée pour recevoir la cible à partir d'une extrémité d'entrée et pour expulser la cible à partir d'une extrémité de sortie sous forme d'agrégats atomiques, et un système d'entrée de fluide à régulation de température. Le système d'entrée de fluide à régulation de température est prévu pour refroidir la cible et optimiser les interactions de collision dans la cible pour augmenter la taille et la densité des agrégats atomiques formés à partir de la cible.
PCT/US2008/007763 2007-06-22 2008-06-20 Optimisation de température de sources de rayons x Ceased WO2009038608A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US93688207P 2007-06-22 2007-06-22
US60/936,882 2007-06-22

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WO2009038608A2 true WO2009038608A2 (fr) 2009-03-26
WO2009038608A3 WO2009038608A3 (fr) 2009-05-28

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Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8614177D0 (en) * 1986-06-11 1986-07-16 Vg Instr Group Glow discharge mass spectrometer
US5487078A (en) * 1994-03-14 1996-01-23 Board Of Trustees Of The University Of Illinois Apparatus and method for generating prompt x-radiation from gas clusters
JP3300773B2 (ja) * 1995-02-23 2002-07-08 ミヤチテクノス株式会社 レーザ装置
US5689542A (en) * 1996-06-06 1997-11-18 Varian Associates, Inc. X-ray generating apparatus with a heat transfer device

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WO2009038608A3 (fr) 2009-05-28

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