EP0461119A1 - Dispositif de mesure interferometrique de structures superficielles - Google Patents

Dispositif de mesure interferometrique de structures superficielles

Info

Publication number
EP0461119A1
EP0461119A1 EP19900902162 EP90902162A EP0461119A1 EP 0461119 A1 EP0461119 A1 EP 0461119A1 EP 19900902162 EP19900902162 EP 19900902162 EP 90902162 A EP90902162 A EP 90902162A EP 0461119 A1 EP0461119 A1 EP 0461119A1
Authority
EP
European Patent Office
Prior art keywords
laser
laser sources
measuring
partial beams
phase difference
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.)
Ceased
Application number
EP19900902162
Other languages
German (de)
English (en)
Inventor
Thomas Pfendler
Pawel Drabarek
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0461119A1 publication Critical patent/EP0461119A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02002—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies
    • G01B9/02005—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies using discrete frequency stepping or switching
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
    • G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02002—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies
    • G01B9/02003—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies using beat frequencies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02007—Two or more frequencies or sources used for interferometric measurement
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02041—Interferometers characterised by particular imaging or detection techniques
    • G01B9/02044—Imaging in the frequency domain, e.g. by using a spectrometer

Definitions

  • the invention relates to a device for the interferometric detection of surface structures by measuring the phase difference in laser-speckle pairs in the measuring points on this surface.
  • the device according to the invention with the characterizing features of the main claim has the advantage that a very simple arrangement of optical fiber lines can be used for beam splitting and frequency change of a beam.
  • Optical couplers and dividers for such fiber lines are available as common components.
  • the beam guidance is therefore variable and does not require any adjustment, at least in this area.
  • the frequency shift is achieved by a certain extension of a fiber line and frequency modulation or wavelength modulation, which makes the "frequency converter” very simple and inexpensive. Since the fiber lines can be guided very close to one another without any accuracy being important, the entire arrangement is not only very inexpensive but also very compact.
  • a particular problem with the measurement is that the height differences to be measured on the measuring surface in the known methods must be less than half a wavelength of the measuring beam. Differences in height, which differ by half a wavelength, result in the same signal, namely a phase difference of 360 °.
  • the wavelength of the measuring beam must be selected accordingly in the known measuring devices, that is to say certain pre-information or estimates of the roughness and structure of the surface to be measured are required.
  • this problem takes a back seat.
  • the phase differences are determined in a known form, and then a comparison of the various determined phase differences is carried out.
  • a simple design is achieved in that the divider device is provided with an optical coupler for the at least two input-side optical fiber lines.
  • the wavelengths of the different laser sources differ only slightly.
  • the accuracy of the result increases with a larger number of laser sources.
  • the laser sources work at the same time and that a number of photo receivers corresponding to the number of laser sources is provided in the photo receiving device, means in front of these photo receivers being provided with means for splitting the laser beam into its components with different wavelengths and for feeding to the individual photo receivers is.
  • the laser sources can be controlled very easily, and a very simple evaluation is possible due to the simultaneous presence of the measurement results.
  • several photo receivers and a device for splitting the laser beam are required.
  • the laser sources can also work sequentially, in which case only a single photo receiver is required in the photo receiver device.
  • a memory device for temporarily storing the measurement results is required for the evaluation, and the laser sources must be controlled sequentially.
  • Fig. 1 is a schematic representation of the measurement setup for sequential operation and Fig. 2 shows a detail of the measurement setup for the
  • three laser sources 10 to 12 designed as laser diodes are provided, the frequency of which by current modulation, in particular injection current modulation.
  • the dotted line between the laser sources 11 and 12 is intended to indicate that the number of laser sources can also be higher.
  • at least two laser diodes must be provided.
  • the laser beams emerging from these laser diodes are each fed via optical fiber lines 13 to 15 to a coupler and divider device 16, where they are first coupled to form a single beam and then divided again into two identical output beams, namely into a reference beam. and into a measuring beam.
  • the reference beam is continued in an optical fiber line 17 and the measuring beam in an optical fiber line 18.
  • the optical fiber line 17 has a loop 19 for the reference beam, which extends this fiber line 17 relative to the fiber line 18 by the length of this loop 19.
  • the reference beam and the measuring beam leave the fiber lines 17, 18 at their ends, are collimated and fed to a deflection device which consists of a mirror 22 inclined at 45 and a beam splitter 23 which is at an angle of 45 ° is inclined in the opposite direction.
  • the reference beam emerging from the end 20 is deflected at right angles at the mirror 22, passes through the beam splitter 23 and arrives at a photo receiver 24 designed as a photodiode in a photo receiver device 25.
  • the measuring beam runs from the end 21 through the beam _ _
  • the splitter 23 to the surface of an object 26 to be measured is reflected from there and also passed from the beam splitter 23 to the photo receiver 24.
  • the two components overlap after the interferometer pr ip and thus illuminate the photo receiver unit.
  • the received signal from the photo receiver unit 24 is processed in the photo receiver device 25, if necessary, and fed to an evaluation device 27 which, together with a frequency modulator 28, forms the control and evaluation electronics 29.
  • the frequency modulator 28 the laser sources 10 to 12 can be current-modulated to change their frequency or wavelength, in particular inject-current-modulated, and can be switched on sequentially in certain time ranges.
  • the measuring device shown in FIG. 1 operates in the so-called monocolor mode, that is, the laser sources 10 to 12 are switched on sequentially in their respective time range, so that only laser light of one wavelength is ever present.
  • this laser light of one wavelength is divided into a measuring beam and a reference beam in the coupler and divider device 16.
  • the reference beam experiences a relative frequency shift of e.g. a few kHz.
  • This reference beam and the measuring beam reflected on the surface of the object 26 are then superimposed after the interferometer principle and illuminate the photoreceiver 24, whose measuring signal thus also has a frequency of e.g. has a few kHz, which corresponds to the frequency difference between the measuring and reference beams
  • a phase difference arises which depends on these height differences. This is described in more detail in the prior art specified at the outset. For example, a profile change that corresponds to half a wavelength of the laser light results in a measurement signal shift of 360.
  • phase difference angles of 36 and 72 are thus recognized. If, on the other hand, height differences on the object 26 were an entire wavelength of the laser light from the first laser source 10, then phase difference angles of 72 and 144 ° would result. In this way, exact measurements of surface structures are also possible, the height differences of which are multiples of half a wavelength.
  • the second exemplary embodiment shown in detail in FIG. 2 largely corresponds to the first exemplary embodiment.
  • all three laser sources 10 to 12 work simultaneously, and the correspondingly superimposed laser beams with the three different wavelengths are shortly before the photo receiver device 30 by a prism 34 or another wavelength divider, for example an optical grating, in their individual components different wavelengths split.
  • the evaluation can take place here simultaneously, since all three measured values are available simultaneously, while in the first embodiment an intermediate storage is required before the phase differences are can be voted.
  • the mode of operation on which FIG. 2 is based can also be referred to as multicolor operation

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)

Abstract

Un dispositif permet de mesurer par interférométrie des structures superficielles par interférométrie en mesurant la différence de phase de paires de tavelures laser aux points de mesure de ladite surface. Le dispositif comprend au moins deux sources (10-12) de lumière laser dont la fréquence ou la longueur d'onde est modulée, un diviseur (16) qui divise les faisceaux lasers générés en deux faisceaux partiels, un décaleur pour décaler les fréquences des deux faisceaux partiels l'une par rapport à l'autre et un dispositif de guidage des faisceaux qui guide jusqu'à un dispositif photorécepteur (25) les deux faisceaux partiels, l'un en tant que faisceau de référence et l'autre, interférométriquement superposé au premier, en tant que faisceau de mesure guidé jusqu'au point de mesure et réfléchi par celui-ci. Un dispositif d'évaluation (27) qui détermine la différence des phases est connecté au dispositif photorécepteur (25). Le diviseur est connecté du côté entrée par une fibre optique (13-15) avec au moins les deux sources de lumière laser (10-12), et les deux faisceaux partiels émis par le diviseur (16) se propagent pendant au moins une partie de leur parcours dans des fibres optiques (17 et 18) également, une des fibres optiques (17) ayant un prolongement (19) par rapport à l'autre. On peut ainsi générer de manière simple et économique un faisceau de mesure et un faisceau de référence ayant une différence minime de fréquence, avec une structure compacte qui requiert des ajustements minimes.
EP19900902162 1989-02-28 1990-02-01 Dispositif de mesure interferometrique de structures superficielles Ceased EP0461119A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3906118A DE3906118A1 (de) 1989-02-28 1989-02-28 Vorrichtung zur interferometrischen erfassung von oberflaechenstrukturen
DE3906118 1989-02-28

Publications (1)

Publication Number Publication Date
EP0461119A1 true EP0461119A1 (fr) 1991-12-18

Family

ID=6375049

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900902162 Ceased EP0461119A1 (fr) 1989-02-28 1990-02-01 Dispositif de mesure interferometrique de structures superficielles

Country Status (5)

Country Link
US (1) US5293215A (fr)
EP (1) EP0461119A1 (fr)
JP (1) JPH04504615A (fr)
DE (1) DE3906118A1 (fr)
WO (1) WO1990010195A1 (fr)

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JPH06500857A (ja) * 1990-08-31 1994-01-27 コモンウェルス・サイエンティフィック・アンド・インダストリアル・リサーチ・オーガナイゼイション 干渉顕微鏡
DE4033253A1 (de) * 1990-10-19 1992-04-23 Hommelwerke Gmbh Optisches interferometer
IL100655A (en) * 1991-02-08 1994-11-28 Hughes Aircraft Co Profile gauge for interferometric laser
GB9116115D0 (en) * 1991-07-25 1991-09-11 Nat Res Dev Fibre-optic probe for surface measurement
AT399222B (de) * 1992-10-19 1995-04-25 Tabarelli Werner Interferometrische einrichtung zur messung der lage eines reflektierenden objektes
JP3234353B2 (ja) * 1993-06-15 2001-12-04 富士写真フイルム株式会社 断層情報読取装置
US5506672A (en) * 1993-09-08 1996-04-09 Texas Instruments Incorporated System for measuring slip dislocations and film stress in semiconductor processing utilizing an adjustable height rotating beam splitter
US5474381A (en) * 1993-11-30 1995-12-12 Texas Instruments Incorporated Method for real-time semiconductor wafer temperature measurement based on a surface roughness characteristic of the wafer
DE19708163A1 (de) * 1997-02-28 1998-09-10 Bosch Gmbh Robert Schaltung zur Signalaufbereitung von in einem Heterodyninterferometer auftretenden Signalen
DE19721881C2 (de) 1997-05-26 1999-05-20 Bosch Gmbh Robert Interferometrische Meßvorrichtung
DE19721882C2 (de) * 1997-05-26 1999-04-29 Bosch Gmbh Robert Interferometrische Meßvorrichtung
DE19721842C2 (de) 1997-05-26 1999-04-01 Bosch Gmbh Robert Interferometrische Meßvorrichtung
DE29715904U1 (de) * 1997-09-01 1997-10-23 Omeca Messtechnik Gmbh Interferenzoptische Meßeinrichtung
US6094269A (en) * 1997-12-31 2000-07-25 Metroptic Technologies, Ltd. Apparatus and method for optically measuring an object surface contour
DE19808273A1 (de) * 1998-02-27 1999-09-09 Bosch Gmbh Robert Interferometrische Meßeinrichtung zum Erfassen der Form oder des Abstandes insbesondere rauher Oberflächen
DE19819762A1 (de) * 1998-05-04 1999-11-25 Bosch Gmbh Robert Interferometrische Meßeinrichtung
US6151127A (en) * 1998-05-28 2000-11-21 The General Hospital Corporation Confocal microscopy
US6181430B1 (en) * 1999-03-15 2001-01-30 Ohio Aerospace Institute Optical device for measuring a surface characteristic of an object by multi-color interferometry
DE10204133B4 (de) * 2002-02-01 2004-05-27 Robert Bosch Gmbh Interferometrisches Messverfahren und Vorrichtung
US7106446B2 (en) * 2002-06-21 2006-09-12 Therma-Wave, Inc. Modulated reflectance measurement system with multiple wavelengths
US20040001662A1 (en) * 2002-06-27 2004-01-01 Biotechplex Corporation Method of and apparatus for measuring oscillatory motion
US6762846B1 (en) 2002-09-19 2004-07-13 Nanometrics Incorporated Substrate surface profile and stress measurement
US7280215B2 (en) * 2003-09-24 2007-10-09 Therma-Wave, Inc. Photothermal system with spectroscopic pump and probe
DE102004010754A1 (de) * 2004-03-05 2005-09-22 Robert Bosch Gmbh Interferometrische Messanordnung
DE102010037207B3 (de) * 2010-08-27 2011-11-03 Technische Universität München Rauheits-Messvorrichtung und -Messverfahren
CN112098039B (zh) * 2020-09-08 2021-06-18 中国科学院力学研究所 一种高超声速流场脉动密度测量系统及测量方法
CN113029036B (zh) * 2021-04-23 2023-03-28 中国工程物理研究院流体物理研究所 一种非接触式物体三维轮廓光学检测装置及检测方法

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US4830486A (en) * 1984-03-16 1989-05-16 Goodwin Frank E Frequency modulated lasar radar
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JPS62127641A (ja) * 1985-11-29 1987-06-09 Ando Electric Co Ltd 光部品測定用光源選択装置

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Also Published As

Publication number Publication date
US5293215A (en) 1994-03-08
WO1990010195A1 (fr) 1990-09-07
DE3906118A1 (de) 1990-08-30
JPH04504615A (ja) 1992-08-13

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