EP1463929A1 - Procede et dispositif de reconnaissance de gaz etranger dans des systemes optiques de formation d'images et/ou de guidage de faisceaux - Google Patents

Procede et dispositif de reconnaissance de gaz etranger dans des systemes optiques de formation d'images et/ou de guidage de faisceaux

Info

Publication number
EP1463929A1
EP1463929A1 EP02806029A EP02806029A EP1463929A1 EP 1463929 A1 EP1463929 A1 EP 1463929A1 EP 02806029 A EP02806029 A EP 02806029A EP 02806029 A EP02806029 A EP 02806029A EP 1463929 A1 EP1463929 A1 EP 1463929A1
Authority
EP
European Patent Office
Prior art keywords
wave field
analysis
useful
protective gas
impurities
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP02806029A
Other languages
German (de)
English (en)
Inventor
Gerhart Schroff
Michael Stetter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP1463929A1 publication Critical patent/EP1463929A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/12—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/12—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure
    • B23K26/127—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure in an enclosure
    • B23K26/128—Laser beam path enclosures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/70—Auxiliary operations or equipment
    • B23K26/702—Auxiliary equipment
    • B23K26/705—Beam measuring device

Definitions

  • the invention relates to a method and an arrangement for the detection of foreign gases or impurities in the beam path of optical imaging or beam guiding systems according to the preamble of claims 1 and 16.
  • the entire beam path is filled with an extremely pure gas that does not absorb the laser light used or, more generally, the electromagnetic waves used , filled.
  • disruptive influences of foreign gases or other impurities such as very fine aerosols or smoke or dust particles on the imaging properties are to be excluded.
  • the entire beam path is slowly flushed with an extremely pure gas. Flushing the beam path may also be necessary if some of the components used in the construction of the optical system outgas and thus - mostly very slowly and hard to predict - foreign gases get into the beam path.
  • the use of very pure protective gases causes very high costs.
  • the object of the invention is to use a method and an arrangement of the type mentioned in the introduction to rapidly and reliably detect and evaluate the influences of foreign substances present in the protective gas, even under harsh operating conditions.
  • the invention is based on the knowledge that in optical systems which contain gases between the individual optical components (such as mirrors, beam splitters, lenses, optical gratings or prisms), the optical properties depend on the refractive index of the gas used.
  • gases such as mirrors, beam splitters, lenses, optical gratings or prisms
  • the essential influence of foreign gases or other contaminants, which absorb these electromagnetic useful wave fields radiating through the optical system, can be seen in the fact that these foreign gases or contaminants locally or also in the entire beam path of the useful wave field lead to heating of the protective gas used and thus changing the refractive index of the gas and thus the imaging properties.
  • the protective gas surrounding the beam path and usually also the optical components is examined for such foreign gases or impurities by means of the photo-acoustic effect .
  • the shielding gas to be examined is exposed in an examination volume to an intensity-modulated electromagnetic analysis wave field emitted by a beam source (for example by a laser). If this wave field is selected so that at least frequency fractions of these waves can be absorbed by the foreign gases or contaminants, part of the molecules and / or atoms of the foreign gases or contaminants are absorbed by the electromagnetic see waves brought into an energetically excited state.
  • the excited molecules or atoms can release their excitation energy in whole or in part and convert them, for example, into translation, rotation and vibration energy of the collision partners.
  • the increase in the translation energy of the molecules or atoms present in the investigation volume means an increase in temperature and thus an increase in pressure (photoacoustic effect). Periodic pressure fluctuations result from the wave field radiated into the examination volume and changed in intensity periodically.
  • the great advantage of this type of determination of the influences of foreign gases or impurities is to be seen in the direct connection between the heating of the protective gas and the photoacoustic signals used to identify these influences. If, on the other hand, you wanted to work with mass spectrometers, you would first have to identify and clearly identify all foreign gases or impurities in question, their concentration should be determined and the expected thermal influences should be calculated using a comprehensive table.
  • the photoacoustic signal is advantageously used as a measure for the changed imaging properties of the optical system and / or for the concentration of the foreign substances.
  • the spectral composition can advantageously be chosen such that the analysis wave field contains all or at least some frequency components of the useful wave field and / or the useful wave field contains all and / or some frequency components of the analysis wave field.
  • a preferred embodiment of the invention provides that the spectral composition of the useful wave field and the analysis wave field match.
  • an analysis laser beam can be used to estimate the influence of foreign gases or impurities on the imaging properties of the laser cutting system (and thus on the cutting quality), which preferably only one, several or all of these laser lines or even more additional Contains laser lines.
  • the analysis laser beam contains all laser lines of the useful laser beam, but no further ones, then the intensity distribution of the individual lines of the analysis laser beam can advantageously be selected to be equal to the intensity distribution of the lines of the useful laser beam (with which the cut is made).
  • the light sources in the UV range can also be used in imaging systems of exposure systems, or the procedure can also be used in laser fusion arrangements, etc.
  • a preferred embodiment of the invention provides that the intensity-modulated analysis wave field is generated by preferably using a beam splitter or a partially transparent mirror or a mirror provided with a bore or a scattering body, such as a thin wire, for a low intensity component from the useful wave field is decoupled.
  • a further advantageous embodiment of the invention provides that the intensity of the analysis wave field is modulated by pulsing the excitation power of the beam source or by periodic masking, preferably by means of a mechanical interrupter wheel.
  • a second laser beam can also be coupled out of the laser very simply by not only laser power from the laser resonator at the output window at which the useful laser beam emerges from the laser decouples, but also on a resonator mirror or another component located in the resonator, such as an etalon, decouples another laser beam with low laser power.
  • a further advantageous embodiment of the invention provides that the examination volume is arranged within the imaging and / or beam guidance system in such a way that gas exchange is possible without great time delays.
  • the signals that are photoacoustically generated in the examination volume are advantageously converted into electrical output signals in a sound sensor designed, for example, as a microphone and evaluated with determination of their intensity.
  • a sound sensor designed, for example, as a microphone and evaluated with determination of their intensity.
  • the beam source 11 designed as a laser emits the useful wave beam 1 as a collimated, slightly divergent laser beam.
  • the beam path of the useful wave field 1 there is a beam splitter 6 and then the actual optical components 10 ′ of the optical imaging or beam guiding system 10, which direct the useful wave field 1 onto the surface 16 to be exposed, processed or evaporated, for example of wafers to be cut or should suitably image targets to be heated in laser fusion.
  • the analysis wave field 4 is coupled out of the useful wave field 1 by means of the beam splitter 6.
  • a decoupling window 19 and a modulation unit 12 are located one after the other in the beam path of the analysis wave field 4.
  • the analysis wave field 4 can emerge from the housing of the imaging or beam guidance system 10 through the decoupling window 19.
  • the analysis beam 4 can be modulated in intensity.
  • the detection chamber 3 is located in the beam path of the analysis wave field 4 'modulated in this way. It has an inlet and outlet window 18, 18', an interior 17 which can be filled with gas and an acoustic sensor 7 arranged in the interior and designed as a microphone.
  • the detection chamber 3 is provided with a filling connection 8 and an evacuation connection 9. It can be filled with the protective gas to be examined for foreign gases or impurities by means of these connections and, after an analysis, emptied, evacuated or also flushed. Since the intensity-modulated analysis wave field 4 'has the same spectral composition as the useful wave field 1 at all times, energy from the analysis wave field 4' is absorbed by the foreign gases or impurities contained in the protective gas if and only if energy from the useful wave field 1 is also absorbed.
  • the radiation energy absorbed when the detection chamber 3 is irradiated by the foreign gases or impurities contained in the protective gas leads to Photoacoustic effect on temperature changes and thus on pressure fluctuations with the frequency impressed by the modulation frequency, which can be converted at the sound sensor 7 into electrical output signals. Since the temperature changes generated are directly proportional to the pressure fluctuations generated under suitable conditions, such as a beam diameter, the dimensions of the detection chamber, the shielding gas used, the pressure set in the detection chamber and the external gases to be detected a photoacoustic signal 5 generated in this way is a unique feature for assessing the beam properties of the optical imaging or beam guidance system.
  • the filling connection 8 of the detection chamber 3 is connected via the line 22 to the drain opening 21 of the beam guidance system 10 and is provided with a filling valve 22 '.
  • a sample of the protective gas located in the beam guiding system 10 can then be taken via the discharge opening 21 for analysis.
  • the imaging or beam guidance system 10 can be filled with protective gas via the inlet opening 20 and / or flushed by continuously introducing protective gas. The shielding gas then emerges from the beam guidance system at leaks or other openings.
  • the evacuation connection 9 of the detection chamber is connected to a vacuum pump 24 via line 23 and is provided with an evacuation valve 23 '.
  • the shielding gas is analyzed for foreign gases and / or impurities as follows:
  • Evacuation valve 23 ' is opened until a sufficiently deep vacuum is established in the detection chamber 3 and / or the pressure falls below.
  • the vacuum can preferably be measured by means of a pressure sensor installed in the line 23 between the evacuation valve 23 'and the detection chamber 3;
  • the evacuation valve 23 ' is closed.
  • the pressure sensor mounted in line 23 between the evacuation valve 23 'and the detection chamber 3 indicates the desired pressure, preferably atmospheric pressure
  • the filling valve 22' is closed and the protective gas is then analyzed for any foreign gases or impurities that may be present.
  • the cleaning of the detection chamber 3 can then be controlled by a sufficiently deep evacuation by means of the evacuation valve 23 '.
  • a constant volume flow can be drawn through the detection chamber by attaching a throttle in the line between the vacuum pump 24 and the evacuation valve 23 'with the evacuation valve and the filling valve open, so that a continuous analysis of the protective gas can be carried out.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Analytical Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

L'invention concerne un procédé et un dispositif de reconnaissance de substances étrangères dans la trajectoire des faisceaux de systèmes optiques de formation d'images ou de guidage de faisceaux (10), dans lesquels l'enceinte entourant la trajectoire des faisceaux ainsi que des composants optiques (10') est remplie ou purgée au moyen d'un gaz inerte. Selon l'invention, ledit gaz inerte est exposé à un champ d'ondes électromagnétiques analytique (4'), modulé en intensité, dans un volume test (3). Un signal photoacoustique (5) est produit pour détecter des impuretés ou des gaz étrangers au moyen d'un effet photoacoustique, lorsque les composantes de fréquences du champ d'ondes analytique (4') sont absorbées par les gaz étrangers et/ou les impuretés.
EP02806029A 2002-01-08 2002-12-30 Procede et dispositif de reconnaissance de gaz etranger dans des systemes optiques de formation d'images et/ou de guidage de faisceaux Withdrawn EP1463929A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10200349 2002-01-08
DE10200349A DE10200349A1 (de) 2002-01-08 2002-01-08 Verfahren und Anordnung zur Fremdgaserkennung im Strahlengang optischer Abbildungs- und/oder Strahlführungssysteme
PCT/EP2002/014806 WO2003058213A1 (fr) 2002-01-08 2002-12-30 Procede et dispositif de reconnaissance de gaz etranger dans des systemes optiques de formation d'images et/ou de guidage de faisceaux

Publications (1)

Publication Number Publication Date
EP1463929A1 true EP1463929A1 (fr) 2004-10-06

Family

ID=7711622

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02806029A Withdrawn EP1463929A1 (fr) 2002-01-08 2002-12-30 Procede et dispositif de reconnaissance de gaz etranger dans des systemes optiques de formation d'images et/ou de guidage de faisceaux

Country Status (4)

Country Link
EP (1) EP1463929A1 (fr)
AU (1) AU2002367326A1 (fr)
DE (1) DE10200349A1 (fr)
WO (1) WO2003058213A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9358636B2 (en) 2008-06-20 2016-06-07 Trumpf Werkzeugmaschinen Gmbh + Co. Kg Laser processing machine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10253162B4 (de) * 2002-11-14 2005-11-03 Infineon Technologies Ag Verfahren zum Spülen einer optischen Linse
DE102004029672B4 (de) * 2004-06-11 2007-04-12 Novapax Kunststofftechnik Steiner Gmbh & Co. Kg Vorrichtung zur Bearbeitung von Werkstücken
DE102004034832B4 (de) * 2004-07-19 2014-05-22 Gerhart Schroff Verfahren und Anordnung zur Gasanalyse

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Publication number Priority date Publication date Assignee Title
DE2820444C2 (de) * 1978-05-10 1982-04-29 Aleksandr Fedorovič Egorov Verfahren und Vorrichtung zur quantitativen Bestimmung des Fremdgas- bzw. -dampfgehaltes in einem Gasgemisch
DE3707622A1 (de) * 1987-03-10 1988-09-22 Pierburg Gmbh Verfahren und vorrichtung zum messen geringer gaskonzentrationen
DE3804134A1 (de) * 1988-02-11 1989-08-24 Felten & Guilleaume Energie Verfahren und einrichtung zum messen der konzentration eines fremdgases in einem gasgemisch unter nutzung eines moires
IT1248992B (it) * 1990-06-25 1995-02-11 Cise Spa Cella optoacustica per la misura di concentrazioni di specie chimiche in fluidi in genere
DE4126885A1 (de) * 1991-08-14 1993-02-18 Michael Rupp Verfahren und vorrichtung zum untersuchen von behaeltnissen auf fremdstoffe
DE4342624C1 (de) * 1993-12-14 1995-06-29 Deutsche Forsch Luft Raumfahrt Vorrichtung zum Erzeugen eines definierten Ozon-Fremdgas-Gemisches und Verfahren zum Bereitstellen eines definierten Ozon-Fremdgas-Gemisches in einem geschlossenen Behälter
DE4427314C2 (de) * 1994-08-02 1997-02-20 Graessle Walter Gmbh Vorrichtung zur Untersuchung von Behältern auf Fremdgase
US5929981A (en) * 1996-06-18 1999-07-27 Ohmeda Inc. System for monitoring contamination of optical elements in a Raman gas analyzer
NL1007970C2 (nl) * 1998-01-07 1999-07-08 Stichting Tech Wetenschapp Werkwijze voor het spectroscopisch bepalen van een vluchtige organische verbinding in een door een zoogdier afgegeven gas.
US6442182B1 (en) * 1999-02-12 2002-08-27 Lambda Physik Ag Device for on-line control of output power of vacuum-UV laser
DE19840345B4 (de) * 1998-09-04 2004-09-30 Dräger Medical AG & Co. KGaA Verfahren und Vorrichtung zum quantitativen Aufspüren eines vorgegebenen Gases

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See references of WO03058213A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9358636B2 (en) 2008-06-20 2016-06-07 Trumpf Werkzeugmaschinen Gmbh + Co. Kg Laser processing machine

Also Published As

Publication number Publication date
AU2002367326A1 (en) 2003-07-24
WO2003058213A1 (fr) 2003-07-17
DE10200349A1 (de) 2003-07-17

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