US20020072301A1 - Apparatus and method for detecting a work piece in an automatic processing apparatus - Google Patents

Apparatus and method for detecting a work piece in an automatic processing apparatus Download PDF

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Publication number
US20020072301A1
US20020072301A1 US09/962,412 US96241201A US2002072301A1 US 20020072301 A1 US20020072301 A1 US 20020072301A1 US 96241201 A US96241201 A US 96241201A US 2002072301 A1 US2002072301 A1 US 2002072301A1
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United States
Prior art keywords
work piece
ultrasound
holder
ultrasound waves
intensity
Prior art date
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Abandoned
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US09/962,412
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English (en)
Inventor
Stephan Bradl
Olaf Heitzsch
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Individual
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Individual
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Publication of US20020072301A1 publication Critical patent/US20020072301A1/en
Abandoned legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/22—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring existing or desired position of tool or work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/006—Arrangements for observing, indicating or measuring on machine tools for indicating the presence of a work or tool in its holder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/16—Programme controls
    • B25J9/1694—Programme controls characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion

Definitions

  • Wafer polishing devices are used for the polishing of wafers, monocrystalline, flat silicon disks which can be used for the production of integrated circuits.
  • the wafer is placed, in this case, on a polishing cloth and held by a polishing tool (polishing head, “carrier”).
  • a polishing agent (“slurry”) is applied to the polishing cloth, and a relative movement is produced between the polishing cloth and the wafer.
  • wafer losses on the so-called polishing platen may occur as a result of various irregularities, such as tool problems, process instabilities, faults in the transport or in the provision of the wafers.
  • rapid detection of a wafer loss is important in order to be able to interrupt the polishing process.
  • Polishing machines of the prior art therefore to some extent have optical sensors which, using the different optical reflection capacity of the wafer, on the one hand, and the substrate (polishing cloth) on the other hand, are able to detect a loss of the wafer.
  • these sensors are suitable to only a limited extent for the reliable detection of the presence of a wafer, since they cannot always distinguish between the wafer and the polishing cloth. They can therefore not be employed universally and, from time to time, lead to erroneous detection.
  • many of the polishing agents normally used lead to a coloration of the polishing cloth, which results in a change in the reflection behavior. This effect occurs above all in the case of polishing agents for metal polishing.
  • the proportion of erroneous detections is increased, which runs counter to the trouble-free and automatic processing of the wafers in the polishing machine.
  • a further method of detecting the presence or absence of a wafer has been proposed in the prior art.
  • the vacuum on the polishing head is measured, in order in this way to detect a possible loss of the wafer by a dip in vacuum that occurs.
  • a method of detecting a presence of a work piece in an automatic processing apparatus includes the steps of providing a holder for the work piece in the automatic processing apparatus; irradiating the holder and/or at least part of a surroundings of the holder with ultrasound waves; receiving reflected ultrasound waves; and using the reflected ultrasound waves to determine if the work piece is held in the holder or if the work piece is located outside the holder.
  • the invention makes use of the different acoustic reflection capacity of a work piece as compared with its surroundings, for example a gripping arm or a substrate.
  • the invention is used in particular to provide a wafer loss detection system that operates reliably.
  • the invention is intended to include the application of sound waves to the detection of the presence and absence of a work piece to be processed.
  • the invention provides work piece detection mechanisms precisely for very flat work pieces.
  • the detection is preferably carried out by using the ratio of emitted to received ultrasound waves. Processing of a work piece is usually not started if its absence is detected. However, in programming terms, it may be expedient instead to determine the presence of the work piece in the surroundings of the holder. However, these alternatives correspond in terms of their result, since absence from the holder results in a presence in the surroundings.
  • the irradiating step, the receiving step and the using step can be carried out repetitively during the entire processing of the work piece.
  • the processing is preferably interrupted if the absence of a work piece from the holder is detected.
  • the invention is in particular directed to applications in which the work piece is flat, for example a wafer.
  • the holder has a support plane for holding the wafer.
  • the invention provides that the holder has a polishing head and a polishing cloth within a polishing apparatus.
  • the invention is likewise directed to an apparatus for detecting the presence of a work piece in an automatic processing apparatus, provision being made for an ultrasound transmitter for irradiating the area of a work piece holder in the processing apparatus, at least one ultrasound receiver and a detection device for detecting the presence of a work piece.
  • the ultrasound receiver preferably contains a means or is programmed for converting the intensity of the received ultrasound waves into an electrical signal.
  • the detection device preferably contains means (or programmed) for determining the intensity of the ultrasound waves received by the ultrasound receiver, means (or programmed) for comparing the intensity with the intensity of the ultrasound waves emitted by the ultrasound transmitter, and means (or programmed) for deciding about the presence or absence of a work piece.
  • the detection device can contain a control device for starting and interrupting the processing of a work piece.
  • a plurality of ultrasound receivers can be present in one apparatus.
  • the apparatus can be equipped in such a way that the ultrasound transmitter can output directed ultrasound waves.
  • FIG. 1 a is a block diagram of a detection apparatus in a processing apparatus having a gripping arm for holding a work piece according to the invention
  • FIG. 1 b is a block diagram of the processing apparatus without the work piece
  • FIG. 2 a is a block diagram of a detection apparatus in a wafer polishing system with a wafer.
  • FIG. 2 b is a block diagram of the detection apparatus in the wafer polishing system after the loss of the wafer.
  • the present invention makes use of an acoustic reflection capacity of work pieces, which always differs from the reflection capacity of the background, for example a polishing cloth in a wafer polishing system, or from the reflection capacity of an empty space, which exists in the absence of a work piece between the holders of a gripping arm.
  • ultrasound waves of a defined intensity are emitted and strike the work piece, if present, and/or strike the surroundings, for example a polishing cloth, of the work piece. From there, a portion of the ultrasound waves is reflected and received by an ultrasound receiver.
  • a detection device that is to say a controller, for example a process computer, then carries out a detection method in which a decision is made as to whether there is a work piece at the proper point or not, use being made of the different reflection capacity of the work piece as compared with the holder or the background.
  • a ratio of the intensities of the emitted and the received ultrasound waves is preferably determined.
  • FIG. 1 a there is shown in schematic form a configuration having a machine tool with a gripping arm 1 , which holds a work piece 2 .
  • a spindle drive 3 with a milling head 4 is ready to process the work piece 2 .
  • An ultrasound transmitter 5 emits ultrasound waves (arrow), which are reflected by the work piece and pass to the ultrasound receiver 6 . They are converted by the receiver 6 into electrical signals, which are received by a controller 7 via a line 8 and are evaluated there.
  • the work piece 2 reflects a high proportion of the ultrasound waves that strike it, and therefore indicates its presence.
  • FIG. 1 b shows the same machine tool with identical reference symbols, in which no work piece 2 is held by the gripping arm 1 .
  • the ultrasound receiver 6 receives only a few ultrasound waves, so that the absence of the work piece 2 is detected.
  • the present invention can be used particularly beneficially in the case of flat work pieces 2 , such as the wafers described above.
  • the additional difficulty arises that, in the case of flat work pieces, detection by light barriers or the like, for example, is difficult.
  • the wafers are polished on polishing cloths that, in terms of their compressibility (elasticity), differ considerably from a wafer lying on them.
  • the compressibility of the polishing cloth is comparatively high, which, on account of the associated sound absorption coefficient, leads to the sound waves being returned with a considerably lower intensity than in the case of the wafer alone.
  • the polishing cloth and the wafer can therefore be distinguished clearly and simply.
  • FIG. 2 a shows schematically a polishing system for a wafer 12 , having a polishing cloth 11 as the background and a wafer 12 disposed thereon.
  • the detection device 7 has the same structure as in FIGS. 1 a and 1 b, so that the same reference symbols are used.
  • the wafer 12 reflects a large proportion of the ultrasound radiation striking it, so that the received intensity at the ultrasound receiver 6 is high.
  • FIG. 2 b shows the polishing system without the presence of the wafer 12 .
  • the polishing cloth 11 reflects less ultrasound than the wafer 12 , so that correspondingly fewer ultrasound waves are received by the ultrasound receiver 6 .
  • a wafer loss can therefore be detected in a simple way, quickly, independently of the process (e.g. polishing paste, etc.) and independently of the hardware.
  • the controller 7 is used for the detection of the presence or absence of the work piece at the envisaged position. It is equipped with a device to receive the electrical signals generated by the ultrasound receiver 6 via the line 8 . In addition, it has a means that decides whether a work piece is present or not.
  • the controller can also has a means that causes the ultrasound transmitter 5 to emit ultrasound. This can be done via a further line 8 ′, which connects the controller 7 and ultrasound transmitter 5 to each other. In this way, synchronization of emission and measurement is possible, which reduces the influence of possible interference waves. Furthermore, the intensity of the emission can also be controlled and therefore defined clearly.
  • the controller 7 compares the intensity of the emitted ultrasound waves with the intensity of the waves received by the ultrasound receiver 6 , and can carry out the detection of the work piece from their ratio.
  • the various means used for the control may be accommodated, for example, in a process computer.
  • the controller 7 can advantageously intervene directly in the processing of the work piece, by starting the latter and, if necessary, interrupting it. This can be achieved via conventional control lines between the controller 7 and the processing apparatus 3 , 4 .
  • Directed ultrasound which is emitted by a specifically aimed ultrasound transmitter, permits more accurate echo location of the location in the apparatus at which the work piece should be found. In this way, the influence of other elements in the processing apparatus is minimized, which further improves the precision of the decision process of the controller.
US09/962,412 1999-03-24 2001-09-24 Apparatus and method for detecting a work piece in an automatic processing apparatus Abandoned US20020072301A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19913365.4 1999-03-24
DE19913365A DE19913365C2 (de) 1999-03-24 1999-03-24 Verfahren und Vorrichtung zur Erkennung der Anwesenheit eines Wafers in einer automatischen Poliervorrichtung
PCT/DE2000/000943 WO2000057251A1 (de) 1999-03-24 2000-03-24 Vorrichtung und verfahren zur detektion eines werkstückes in einer automatischen bearbeitungsvorrichtung

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2000/000943 Continuation WO2000057251A1 (de) 1999-03-24 2000-03-24 Vorrichtung und verfahren zur detektion eines werkstückes in einer automatischen bearbeitungsvorrichtung

Publications (1)

Publication Number Publication Date
US20020072301A1 true US20020072301A1 (en) 2002-06-13

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US09/962,412 Abandoned US20020072301A1 (en) 1999-03-24 2001-09-24 Apparatus and method for detecting a work piece in an automatic processing apparatus

Country Status (8)

Country Link
US (1) US20020072301A1 (ja)
EP (1) EP1169671B1 (ja)
JP (1) JP3464459B2 (ja)
KR (1) KR100438459B1 (ja)
AT (1) ATE224071T1 (ja)
DE (2) DE19913365C2 (ja)
TW (1) TW467790B (ja)
WO (1) WO2000057251A1 (ja)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004011327B3 (de) * 2004-03-09 2005-11-10 S-Y Systems Technologies Europe Gmbh Vorrichtung und Verfahren zum Bestimmen, ob ein Bauteil fehlt.
KR100711937B1 (ko) * 2005-07-28 2007-05-02 삼성전자주식회사 초음파를 이용한 기판 검사 방법 및 이를 수행하기 위한장치
DE102016116012A1 (de) * 2016-08-29 2018-03-01 Lapmaster Wolters Gmbh Verfahren zum Messen der Dicke von flachen Werkstücken
DE102017118422B4 (de) * 2017-08-11 2020-12-31 Carl Zeiss Industrielle Messtechnik Gmbh Vorrichtung zur vermessung und / oder bearbeitung von werkstücken und verfahren zur erfassung von werkstücken in koordinatenmessgeräten oder bearbeitungsmaschinen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4562756A (en) * 1983-07-19 1986-01-07 Matsushita Electric Industrial Co., Ltd. Numerical control screw tightening machine
US5540098A (en) * 1993-02-16 1996-07-30 Tokyo Electron Limited Transfer device
US5823853A (en) * 1996-07-18 1998-10-20 Speedfam Corporation Apparatus for the in-process detection of workpieces with a monochromatic light source

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5967505A (en) * 1997-03-21 1999-10-19 Levi Strauss & Co. Automatic feeder and inverter for fabric workpieces

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4562756A (en) * 1983-07-19 1986-01-07 Matsushita Electric Industrial Co., Ltd. Numerical control screw tightening machine
US5540098A (en) * 1993-02-16 1996-07-30 Tokyo Electron Limited Transfer device
US5823853A (en) * 1996-07-18 1998-10-20 Speedfam Corporation Apparatus for the in-process detection of workpieces with a monochromatic light source

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Publication number Publication date
JP3464459B2 (ja) 2003-11-10
DE19913365A1 (de) 2000-10-26
ATE224071T1 (de) 2002-09-15
EP1169671B1 (de) 2002-09-11
KR100438459B1 (ko) 2004-07-03
KR20010108385A (ko) 2001-12-07
WO2000057251A1 (de) 2000-09-28
DE50000500D1 (de) 2002-10-17
DE19913365C2 (de) 2002-07-18
EP1169671A1 (de) 2002-01-09
JP2002540409A (ja) 2002-11-26
TW467790B (en) 2001-12-11

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