WO2007107783A1 - Réparation d'un filtre spectral - Google Patents

Réparation d'un filtre spectral Download PDF

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Publication number
WO2007107783A1
WO2007107783A1 PCT/GB2007/050108 GB2007050108W WO2007107783A1 WO 2007107783 A1 WO2007107783 A1 WO 2007107783A1 GB 2007050108 W GB2007050108 W GB 2007050108W WO 2007107783 A1 WO2007107783 A1 WO 2007107783A1
Authority
WO
WIPO (PCT)
Prior art keywords
chamber
filter
source
radiation
carbon
Prior art date
Application number
PCT/GB2007/050108
Other languages
English (en)
Inventor
Robert Bruce Grant
Original Assignee
Edwards Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Edwards Limited filed Critical Edwards Limited
Publication of WO2007107783A1 publication Critical patent/WO2007107783A1/fr

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/70983—Optical system protection, e.g. pellicles or removable covers for protection of mask
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70058—Mask illumination systems
    • G03F7/70191—Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
    • G03F7/70575—Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength

Definitions

  • This invention relates to the repair of a spectral filter through which EUV or other electromagnetic radiation is transmitted from a chamber housing the radiation source.
  • Photolithography is an important process step in semiconductor device fabrication.
  • a circuit design is transferred to a wafer through a pattern imaged on to a photoresist layer deposited on the wafer surface.
  • the wafer then undergoes various etch and deposition processes before a new design is transferred to the wafer surface. This cyclical process continues, building up the multiple layers of the semiconductor device.
  • EUV radiation has poor transmissibility through all materials and gases at atmospheric pressures, and therefore much of the mechanical, electrical and optical equipment located in the lithography tool must be operated in a high-purity vacuum environment.
  • the source of EUV radiation is typically housed within a chamber located adjacent the lithography tool.
  • a thin foil usually formed from zirconium, nickel or silicon, is often used as a window through which EUV radiation is transmitted into the lithography tool.
  • the foil can act as a spectral purity filter (SPF) by restricting the bandwidth of frequencies of electromagnetic radiation entering the tool.
  • SPPF spectral purity filter
  • the source of EUV radiation may be based on excitation of tin, lithium, or xenon.
  • a xenon plasma is generated, either by stimulating xenon by an electrostatic discharge or by intense laser illumination.
  • Electronic transitions of highly charged xenon species Xe +10 within the plasma to Xe +11 generate EUV radiation. Consequently, the source of EUV radiation also acts as a source of high energy particles. These particles can impact on the surface of the SPF, and cause atoms to be sputtered from the SPF.
  • SPFs tend to have a thickness in the range from 200 to 1000 nm, and so the impact of the charged particles on the surface of the SPF can lead to the growth of holes in the SPF, both by the enlargement of existing holes in the SPF and by the formation of new holes. This can result in contamination of the tool by the passage of gas from the chamber through the SPF. Once the holes have grown beyond a critical value, the SPF will need to be replaced, resulting in costly process downtime and potential re-qualification after the replacement of the SPF.
  • the present invention provides a method of repairing a spectral filter through which electromagnetic radiation passes from a chamber housing a radiation source, the method comprising the step of periodically supplying to the chamber a source of carbon for forming carbonaceous material on the filter to at least reduce the size of holes grown in the filter during generation of the radiation.
  • Electromagnetic radiation such as EUV radiation or X-rays
  • Electromagnetic radiation can promote the deposition of carbonaceous deposits on the filter by stimulating the emission of secondary electrons from the surface of the filter, which interact with the carbon source to form the carbonaceous deposits.
  • This carbonaceous material can block, or at least reduce the size of, holes grown in the filter during generation of the radiation through impact with high energy particles, such as photons and ions.
  • the growth of the holes in the filter may be caused by the generation of holes in the filter, and/or by the enlargement of holes already present in the filter. By blocking the holes in this manner whilst the filter is in situ, contamination of a lithography tool or other device that receives the radiation passing through the filter can be reduced.
  • the present invention provides a method of repairing a spectral filter through which electromagnetic radiation passes from a chamber housing a radiation source, the method comprising the steps of detecting the leakage of gas from the chamber through holes grown in the filter during generation of the radiation, and, depending on the amount of gas passing through the filter, supplying to the chamber a source of carbon for forming carbonaceous material on the filter to at least reduce the size of the holes.
  • the supply of carbon source to the chamber is preferably initiated when the amount of gas passing through the filter is at or above a first value, and is preferably discontinued when the amount of gas passing through the filter is at or below a second value lower than the first, that is, when contamination of a tool that receives the radiation from the chamber is at or below an acceptable level.
  • the leakage of gas through the filter can be detected by a sensor, for example a mass spectrometer or ionisation gauge, for detecting the presence of gas within the tool.
  • Controlling the partial pressure of the carbon source within the chamber can provide one mechanism for controlling the deposition rate. By adjusting the partial pressure of the carbon source, the steady state coverage of carbonaceous deposits can be regulated at an acceptable level.
  • the partial pressure can be conveniently controlled by controlling the rate of supply of the carbon source to the surface.
  • the radiation source is a plasma generated within the chamber.
  • a number of different materials may be used as the source of the plasma, for example, one of lithium, tin and xenon.
  • the source may generate radiation through impact of electrons on a metal or semiconductor surface.
  • X-rays may be generated through the impact of electrons on an aluminium or magnesium surface, or EUV may be generated by impact of electrons on a silicon of beryllium surface.
  • the carbon source is preferably a source of organic molecules.
  • the choice of the carbon source is determined by a number of criteria, including the probability and rate of dissociative chemisorption on the surface, adequate cross-section for activation by secondary electrons, stability against polymerisation, and gas phase adsorption cross-section to EUV radiation. Examples include carbon monoxide, alkanes, alkynes, alkenes, aryl oxygenates, aromatics, nitrogen-containing species and halogen-containing species.
  • the present invention provides apparatus for repairing a spectral filter through which electromagnetic radiation passes from a chamber housing a radiation source, the apparatus comprising means for supplying to the chamber a source of carbon for forming carbonaceous material on the filter, and means for controlling the duration of the carbon source supply to the chamber so that the carbonaceous material blocks holes grown in the filter during generation of the radiation.
  • the present invention provides apparatus for repairing a spectral filter through which electromagnetic radiation passes from a chamber housing a radiation source, the apparatus comprising means for detecting the leakage of gas from the chamber through holes grown in the filter during generation of the radiation, means for supplying to the chamber a source of carbon for forming carbonaceous material on the filter to at least reduce the size of the holes, and means for controlling the supply of the source of carbon to the chamber depending on the amount of gas passing through the filter.
  • the present invention provides apparatus for generating extreme ultra violet (EUV) radiation, the apparatus comprising a chamber having a spectral filter through which EUV radiation is output from the chamber, the chamber housing a source of EUV radiation and means for focussing EUV radiation generated by the source towards the filter, and means for periodically supplying to the chamber a source of carbon for forming carbonaceous material on the filter to at least reduce the size of holes grown in the filter by the impact of particles generated by the source.
  • EUV extreme ultra violet
  • the apparatus comprises a chamber 10 containing a source 12 of EUV radiation.
  • the source 12 may be a discharge plasma source or a laser-produced plasma source.
  • a discharge plasma source a discharge is created in a medium between two electrodes, and a plasma created from the discharge emits EUV radiation.
  • a laser-produced plasma source a target is converted to a plasma by an intense laser beam focused on the target.
  • a suitable medium for a discharge plasma source and for a target for a laser-produced plasma source is xenon, as xenon plasma radiates EUV radiation at a wavelength of 13.5 nm.
  • xenon plasma radiates EUV radiation at a wavelength of 13.5 nm.
  • other materials such as lithium and tin, may be used as the target material, and so the present invention is not limited to the particular material or mechanism used to generate EUV radiation.
  • the invention is also applicable to apparatus generating other forms of electromagnetic radiation.
  • the source 12 may be a source of X-rays, in which X-rays are produced by the impact of electrons on a metal surface, for example Al or Mg.
  • EUV radiation, indicated at 14, generated in chamber 10 is supplied to another chamber 16 optically linked or connected to chamber 10 via, for example, one or more windows 18 formed in the walls of the chambers 10, 16.
  • the window 18 is provided by a spectral purity filter (SPF) comprising a very thin foil, typically formed from zirconium, nickel or silicon, for transmitting EUV radiation into the chamber 16 whilst preventing contaminants from entering the lithography tool chamber 16 from the chamber 10.
  • SPPF spectral purity filter
  • the chamber 16 houses a lithography tool which projects a beam of EUV radiation on to a mask or reticle for the selective illumination of a photoresist on the surface of a substrate, such as a semiconductor wafer.
  • the chamber 10 houses a plurality of reflective surfaces 20.
  • these reflective surfaces may be provided by multi-layer mirrors (MLMs), providing both collection and focussing optics for the radiation.
  • MLMs comprise a plurality of layers, each layer comprising, from the bottom a first layer of molybdenum and a second layer of silicon.
  • An interface barrier layer formed for example from boron carbide, may be provided between each molybdenum and silicon layer.
  • a metallic layer typically formed from ruthenium, may be formed on the upper surface of each MLM to improve the oxidation resistance of the MLMs whilst transmitting substantially all of the EUV radiation incident thereon.
  • collection optics for the EUV radiation are provided by grazing incidence mirrors instead of MLMs.
  • a vacuum pumping system (not shown) is provided for generating a vacuum within the chambers 10, 16.
  • the pumping system may include, for each chamber, both a cryogenic vacuum pump and a transfer pump, such as a turbomolecular pump, backed by a roughing pump.
  • the source 12 of EUV radiation can also be a source of high energy particles, such as ions and photons.
  • ions and photons For example, when a xenon plasma is used as the EUV source, Xe +10 ions can be emitted from the source. These ions can impact on the surface of SPF 18 located within the chamber 10, and cause atoms to be sputtered from those surfaces. The impact of the charged particles on the surface of the SPF 18 can lead to the growth of holes in the SPF 18, both by the enlargement of existing holes in the SPF 18 and by the formation of new holes. If allowed to continue unabated, the growth of holes in the SPF 18 can result in contamination of the chamber 16 by the passage of gas from the chamber 10 through the SPF 18.
  • a layer of carbon on the surfaces of the SPF 18 and reflective surfaces 20 clearly would normally be undesirable; the presence of a carbon coating on the surface of the SPF 18 would reduce its transmissivity, whilst a carbon coating of the surfaces of the reflective surfaces 20 would reduce their reflectivity.
  • the formation of a carbon coating on the surfaces of these components of the apparatus can serve to protect the surfaces from sputtering due to the impact of these ions with the surfaces.
  • the carbon layer formed on the SPF 18 can at least partially block the holes grown in the SPF 18 during the generation of the EUV radiation.
  • a carbon source for the controlled deposition of carbonaceous deposits on the surface of the SPF 18 under EUV radiation is introduced into the chamber 10 from a supply 22. Deliberately supplying a carbon source can overwhelm the effects of background carbon-containing impurities inevitably present in the chamber 10.
  • the carbon source is preferably selected from the group comprising carbon monoxide, alkynes, alkenes, aryl oxygenates, aromatics, nitrogen-containing species and halogen-containing species.
  • suitable oxygenates are alcohols, esters and ethers.
  • suitable nitrogen-containing compounds are amines, pyrrole and its derivatives, and pyridine and its derivatives.
  • suitable halogen-containing compounds are saturated aryl hydrides, unsaturated aryl hydrides, saturated alkyl hydrides, and unsaturated alkyl hydrides.
  • the carbon source is ethyne (C 2 H 2 ).
  • a controlled amount of carbonaceous material can be deposited on the surface of the SPF 18 such that the holes formed in the SPF 18 are at least partially blocked without significant reduction in the transmissivity of the SPF 18 for the EUV radiation.
  • the addition of the carbon source to the chamber 10 may be conducted on a time basis, for example after a chosen number of hours of generation of EUV radiation by the source 12.
  • a sensor 24 may be provided for monitoring the amount of gas entering the chamber 16 from the chamber 10.
  • the sensor 24 outputs a signal indicative of the amount of gas passing through the SPF 18 to a controller 26, which, in response to the received signal, outputs a control signal to a mass flow controller 28 for controlling the rate of supply of the carbon source from the supply 22 to the chamber 10 through inlet 30.
  • the controller 26 may control the mass flow controller 28 to supply the carbon source to the chamber 10 until the signal received from the sensor 24 indicates that the amount of gas passing through the SPF 18 has fallen to, or below, a second level lower than the first.
  • a second sensor 32 may be provided in the chamber 10 for monitoring the partial pressure of the carbon source, with the controller 26 preferably being configured to control the supply rate of the carbon source to the chamber 10 in dependence on the output from this second sensor 32.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Epidemiology (AREA)
  • Public Health (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

L'invention concerne une méthode pour réparer un filtre spectral (18) à travers lequel passent des rayonnements électromagnétiques (14) provenant d'une chambre (10) contenant une source de rayonnement (12) vers un outil lithographique, dans lequel une source de carbone destinée à former un matériau carboné sur le filtre est périodiquement placée dans la chambre pour au moins réduire la dimension des trous se formant dans le filtre pendant l'utilisation de l'outil. Dans un mode de réalisation préféré, la méthode comprend les étapes suivantes : détecter les fuites de gaz de la chambre par les trous, et, en fonction de la quantité de gaz traversant le filtre, fournir la source de carbone à la chambre.
PCT/GB2007/050108 2006-03-23 2007-03-07 Réparation d'un filtre spectral WO2007107783A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0605725.1 2006-03-23
GB0605725A GB0605725D0 (en) 2006-03-23 2006-03-23 Spectral filter repair

Publications (1)

Publication Number Publication Date
WO2007107783A1 true WO2007107783A1 (fr) 2007-09-27

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GB (1) GB0605725D0 (fr)
TW (1) TW200741375A (fr)
WO (1) WO2007107783A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008007134A2 (fr) * 2006-07-14 2008-01-17 Edwards Limited Procédé de contrôle de la contamination d'une surface
WO2011098169A1 (fr) * 2010-02-09 2011-08-18 Asml Netherlands B.V. Source de rayonnement, appareil lithographique et procédé de fabrication de dispositif
WO2013050198A1 (fr) * 2011-10-07 2013-04-11 Carl Zeiss Smt Gmbh Procédé de réglage de la distribution d'intensité dans un système optique d'un appareil d'exposition par projection microlithographique et système optique
DE102012212394A1 (de) 2012-07-16 2013-05-29 Carl Zeiss Smt Gmbh Abtrennvorrichtung und abtrennverfahren für projektionsbelichtungsanlagen
DE102012215698A1 (de) 2012-09-05 2013-08-29 Carl Zeiss Smt Gmbh Überwachungseinrichtung für eine Projektonsbelichtungsanlage und Verfahren zu deren Betrieb
DE102012215697A1 (de) 2012-09-05 2014-03-06 Carl Zeiss Smt Gmbh Blockierelement zum Schutz von optischen Elementen in Projektionsbelichtungsanlagen

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111082874B (zh) * 2019-12-24 2022-09-30 哈尔滨工业大学 基于气体吸收和相位调制的微波光子滤波器

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1186957A2 (fr) * 2000-09-04 2002-03-13 Asm Lithography B.V. Appareil de projection lithographique
US6507641B1 (en) * 1999-10-08 2003-01-14 Nikon Corporation X-ray-generation devices, X-ray microlithography apparatus comprising same, and microelectronic-device fabrication methods utilizing same
US20040061930A1 (en) * 2001-01-26 2004-04-01 Marco Wedowski Narrow-band spectral filter and the use thereof
WO2005101122A2 (fr) * 2004-04-16 2005-10-27 The Boc Group Plc Nettoyage de miroirs multicouches
WO2006056730A2 (fr) * 2004-11-26 2006-06-01 The Boc Group Plc Protection de surfaces exposees a des particules chargees

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6507641B1 (en) * 1999-10-08 2003-01-14 Nikon Corporation X-ray-generation devices, X-ray microlithography apparatus comprising same, and microelectronic-device fabrication methods utilizing same
EP1186957A2 (fr) * 2000-09-04 2002-03-13 Asm Lithography B.V. Appareil de projection lithographique
US20040061930A1 (en) * 2001-01-26 2004-04-01 Marco Wedowski Narrow-band spectral filter and the use thereof
WO2005101122A2 (fr) * 2004-04-16 2005-10-27 The Boc Group Plc Nettoyage de miroirs multicouches
WO2006056730A2 (fr) * 2004-11-26 2006-06-01 The Boc Group Plc Protection de surfaces exposees a des particules chargees

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
K SUGISAKI ET AL.: "Evaluation of contamination deposition on pinholes used in EUV at wavelength PDI", PROCEEDINGS OF SPIE, vol. 5374, 2004, Bellingham,WA,USA, pages 702 - 709, XP002445549 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008007134A2 (fr) * 2006-07-14 2008-01-17 Edwards Limited Procédé de contrôle de la contamination d'une surface
WO2008007134A3 (fr) * 2006-07-14 2008-03-27 Edwards Ltd Procédé de contrôle de la contamination d'une surface
WO2011098169A1 (fr) * 2010-02-09 2011-08-18 Asml Netherlands B.V. Source de rayonnement, appareil lithographique et procédé de fabrication de dispositif
US9164403B2 (en) 2010-02-09 2015-10-20 Asml Netherlands B.V. Radiation source, lithographic apparatus and device manufacturing method
WO2013050198A1 (fr) * 2011-10-07 2013-04-11 Carl Zeiss Smt Gmbh Procédé de réglage de la distribution d'intensité dans un système optique d'un appareil d'exposition par projection microlithographique et système optique
DE102012212394A1 (de) 2012-07-16 2013-05-29 Carl Zeiss Smt Gmbh Abtrennvorrichtung und abtrennverfahren für projektionsbelichtungsanlagen
DE102012215698A1 (de) 2012-09-05 2013-08-29 Carl Zeiss Smt Gmbh Überwachungseinrichtung für eine Projektonsbelichtungsanlage und Verfahren zu deren Betrieb
DE102012215697A1 (de) 2012-09-05 2014-03-06 Carl Zeiss Smt Gmbh Blockierelement zum Schutz von optischen Elementen in Projektionsbelichtungsanlagen

Also Published As

Publication number Publication date
GB0605725D0 (en) 2006-05-03
TW200741375A (en) 2007-11-01

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