WO2019179762A1 - Device and method for measuring a surface temperature of substrates arranged on a rotating susceptor - Google Patents

Device and method for measuring a surface temperature of substrates arranged on a rotating susceptor Download PDF

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Publication number
WO2019179762A1
WO2019179762A1 PCT/EP2019/055447 EP2019055447W WO2019179762A1 WO 2019179762 A1 WO2019179762 A1 WO 2019179762A1 EP 2019055447 W EP2019055447 W EP 2019055447W WO 2019179762 A1 WO2019179762 A1 WO 2019179762A1
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Prior art keywords
value
measuring
reflectivity
emissivity
values
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Application number
PCT/EP2019/055447
Other languages
German (de)
French (fr)
Inventor
Markus LÜNENBÜRGER
Original Assignee
Aixtron Se
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Publication date
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Publication of WO2019179762A1 publication Critical patent/WO2019179762A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/0022—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiation of moving bodies
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/458—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber
    • C23C16/4582—Rigid and flat substrates, e.g. plates or discs
    • C23C16/4583—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally
    • C23C16/4584—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally the substrate being rotated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/46—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for heating the substrate
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/0003—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiant heat transfer of samples, e.g. emittance meter
    • G01J5/0007—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiant heat transfer of samples, e.g. emittance meter of wafers or semiconductor substrates, e.g. using Rapid Thermal Processing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/80—Calibration
    • G01J5/806—Calibration by correcting for reflection of the emitter radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67248—Temperature monitoring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68764—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by a movable susceptor, stage or support, others than those only rotating on their own vertical axis, e.g. susceptors on a rotating caroussel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68771—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by supporting more than one semiconductor substrate
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/0022—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiation of moving bodies
    • G01J2005/0033—Wheel
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J2005/0074—Radiation pyrometry, e.g. infrared or optical thermometry having separate detection of emissivity

Definitions

  • the invention relates to a method and a measuring V oriques for measuring a surface temperature of an in particular radially offset relative to an axis of rotation on a rotating about the rotational axis susceptor angeordne- th substrate, wherein a position at a radial distance from the rotational axis measurement to a first optical reflectivity value of the surface is measured at a first time, then an optical emissivity value at a second time and then a second optical reflectivity value of the surface at a third time, wherein a temperature measured value corrected with the reflectivity value is calculated from the emissivity value.
  • the invention further relates to a CVD reactor with a heater heated by a rotary drive means in a rotation about a rotation axis, a plurality of particular radially offset to the rotational axis arranged substrate receptacles for receiving substrates having susceptor, with a stationary to the reactor housing radially offset from the axis of rotation on the susceptor arranged measuring point, with an optical emission value measuring device and an optical Reflecti- onswert-measuring device, which are adapted to measure mutually different times at the measuring point emissivity values and reflectivity values on the rotating susceptor, and with an evaluation device which calculates temperature values from the emissivity values corrected by means of the reflectivity values or which calculates raw temperatures from the uncorrected emissivity values which are corrected by means of the measured reflectivity values be.
  • a heater heated by a rotary drive means in a rotation about a rotation axis a plurality of particular radially offset to the rotational axis arranged substrate recept
  • the surface temperature is determined by means of pyrometers.
  • the surface temperatures can be used to control a heating with which the susceptor carrying the substrates is heated to a process temperature.
  • the goal is to achieve the most uniform possible temperature distribution on the substrate surface, even if the substrate bends slightly during the thermal treatment. During bending, a radially uneven contact of the substrate with the bearing surface can cause temperature inhomogeneities.
  • a multi-zone heating with radially different circumferential heaters different radial areas of the susceptor can be heated differently. With rotating substrates on a rotating substrate carrier, the edge regions of the substrate can be heated differently than a central region of the substrate.
  • a different heat transport behavior attributable to a bending of the substrate from the susceptor to the substrate can thereby be compensated.
  • the diameter of a typical wafer is 200 mm.
  • An object of the inventive method is the production of GaN / AlGaN structures on silicon.
  • Essential is the deposition of thin, relatively uniform layers. While the substrate, for example Silicon substrate, for the wavelength of the pyrometer is intransparent, the previously designated layers for the wavelength of the pyrometer are usually semitransparent.
  • the spectral radiation intensity is measured, which starts from the measurement object, ie the substrate surface or from the surface of the susceptor.
  • each radiation intensity can be assigned a temperature.
  • a clear allocation of temperature presupposes that the reflectivity of the
  • Layer surface does not change.
  • the surface emissivity or the surface reflectivity changes greatly during the layer growth.
  • a reflectivity measurement is determined. This is done by means of two mutually different measuring devices, for example, with a pyrometer to determine the emissivity value and a light source and a light detector for determining the reflectivity value.
  • the light source may be a light emitting diode or a laser.
  • the light detector may be a photosensor or phototransistor.
  • the reflectivity measurement takes place at the same measuring wavelength of, for example, 880 nm to 950 nm, at which the emissivity value determination is also carried out. From the emissivity value, a raw temperature value can be determined which is corrected using the reflectivity value. In this way, the Fabry-Perot effect can be compensated.
  • the emissivity value determination and the reflectivity value determination should ideally take place at the same location of the measurement object. In reality, however, this is not possible because the measurements are performed alternately to avoid mutual interference. For example, in pulses of about 100Hz To determine the emission value at a - fixed relative to the reactor housing - fixed measuring point on the rotating susceptor.
  • the determination of the reflectivity of the surface of the measurement object is then performed phase-shifted. Since the susceptor rotates during the measurement and the measuring point is, for example, offset by 200 mm from the axis of rotation, the measuring position on the measuring object moves by about 1 to 2 mm from the time of measuring the emissivity value at the time of measuring the reflectivity value. This has the consequence that the measured emission value does not locally correlate with the measured reflectivity value. However, in the prior art, this reflectivity value is used to correct the raw temperature obtained from the emissivity value. For details of the described measurement method, reference is made to WG Breiland, "Reflectance-Correcting Pyrometry in Thin Film Deposition Applications" 2003 (approved for public release).
  • US 2008/0036997 A1 describes a method for measuring reflection values on rotating substrates.
  • the measurement times are synchronized with the rotation times of the substrate, so that the measuring device supplies time-sequential measured values which are assigned from the same location of the substrate.
  • US 2006/0171442 A1 describes a method for calibrating a pyrometer.
  • US 2012/0293813 Al describes a method for measuring reflection values on a substrate surface.
  • the previously operated measuring method leads to erroneous temperature values, in particular at measuring positions which lie at the edge of the substrate.
  • the invention is based on the object of improving the generic method with regard to the determination of temperature and of specifying a device designed for this purpose.
  • the object is achieved by the invention specified in the claims, wherein the subclaims represent not only advantageous developments of the invention disclosed in the independent claims, but also independent solutions to the problem.
  • a plurality of reflectivity values measured at different times be used to correct in particular exactly one emissivity value.
  • a raw temperature is calculated.
  • This is corrected by the use of at least two reflectivity values, which are measured at two different points in time.
  • the correction can be effected by the formation of an average value between the two reflectivity measured values.
  • a first reflectivity measurement value is determined temporally before the emissivity value and a second reflectivity value is determined temporally after the emissivity value.
  • the average value of these two reflectivity values can be formed in order to obtain one from the emis- value that is measured at a point in time between the two instants at which the reflectivity values are determined, to correct the raw temperature obtained. It can also be a weighted averaging.
  • the two times for determining the reflectivity values used for the correction are preferably immediately adjacent to the time of the determination of the emissivity value.
  • the calculation / correction value formation can be carried out by means of a linear interpolation or by a higher-order interpolation between a plurality of reflectivity measurement values taken in temporally immediately successive fashion.
  • the temperature value obtained by the methods described above can be used to control the heating.
  • An inventive CVD reactor has a susceptor which can be heated by a heating device.
  • the susceptor can rotate about a vertical axis.
  • a rotary drive device is provided which rotates a shaft of the susceptor to bring the firmly connected to the shaft susceptor in a rotation about the drive axis.
  • the heating device is preferably arranged below the susceptor. It may be RF heating, IR heating or other heating.
  • substrate receptacles are provided on the upper side of the susceptor pointing away from the heating. The substrate receptacles can be recesses in the upper side of the susceptor, in which a substrate rests. But they can also be projections for Lüjust réelle.
  • the substrate receptacles are preferably arranged radially offset from the axis of rotation, so that they are arranged on the susceptor fixing substrates off-center of the substrate.
  • a process chamber Above the substrate is a process chamber that is bounded above by a process chamber ceiling.
  • a gas inlet element is provided, with which process gases, for example hydrides of the V main group and organometallic compounds of the III main group are fed into the process chamber.
  • the feed of the process gases is preferably carried out together with a carrier. gergas, for example hydrogen.
  • the gas inlet member may be disposed in the center of the process chamber. It can also extend in a shower head over the entire ceiling of the process chamber.
  • Two measuring devices are provided: a first measuring device with which an emissivity measurement value and a second measuring device can be determined with which a reflectivity value at a measuring position of the surface of the substrate or of the susceptor can be determined.
  • They are preferably optical measuring devices, for example pyrometers, phototransistors or photodiodes.
  • a light source can be used to measure the emissivity.
  • a beam splitter can be achieved that both optical measuring devices have the same beam path, which is preferably directed parallel to the axis of rotation.
  • the measurement can be made through the process chamber ceiling. The latter preferably has an opening for this purpose.
  • the circular arc line (on which the measuring positions are located) can run through the centers of the preferably circular substrates, but the circular arc line can also extend outside the centers of the substrates and in particular by the di e edges of the substrates go through.
  • a plurality of sensor pairs are provided at different radial distances, each sensor pair having a sensor for determining the emissivity value and a sensor for determining the reflectivity value.
  • the fiction, contemporary preamble Direction has an evaluation device with which raw temperature measured values are determined from the emissivity values. For each emissivity value, a raw temperature is determined. This is formed by using at least two reflectivity measured values, which have been determined at mutually different measuring positions on the rotating susceptor, a correction value with which the raw temperature is corrected to a temperature value.
  • the device according to the invention is, in particular, a measuring device for measuring a surface temperature with an evaluation device which uses an emissivity value and at least two reflectivity values to determine a temperature value.
  • FIG. 1 is a schematic sectional view of a first embodiment of a CVD reactor for carrying out the method according to the invention
  • FIG. 2 is a top view of the susceptor 4 arranged thereon substrates 7, as shown in section line II-II in Figure 1,
  • FIG. 3 shows a representation according to FIG. 1 of a second exemplary embodiment
  • FIG. 4 shows a representation according to FIG. 2 of the second exemplary embodiment, Fig. 5 in the form of a curve measured over the angular position
  • Fig. 7 shows schematically the measured at different times ti to t 7
  • the CVD reactors shown in Figures 1 to 4 each have a reactor housing 1, a heater 5 disposed therein, a arranged above the heater 5 susceptor 4 and a gas inlet member 2 for introducing, for example TMGa, TMA1, NH 3 AsHi, PHi and H 2 .
  • the susceptor 4 is driven in rotation about a vertical axis of rotation A by means of a rotary drive device 14.
  • a drive shaft 9 is connected, on the one hand, to the rotary drive device 14 and, on the other hand, to the underside of the susceptor 4.
  • substrates 7 On the technological of the heater 5 horizontal surface of the susceptor 4 are substrates 7.
  • the substrates 7 are located radially outside the axis of rotation A and are held in position by substrate holders which are formed by a cover 8 or by a substrate holder 6.
  • an emission measuring device 10 which is formed by a pyrometer, which measures the emissivity value.
  • a second measuring device 11 is likewise an optimal see measuring device. It has a light detector and a light source. The light source may be a laser. The light detector is a phototransistor. With this reflection value measuring device 11, the reflectivity value is measured. With the two measuring devices 10, 11 emissivity values and reflectivity values can be obtained according to the invention. Via a beam splitter 12, the "measuring beams" of the two measuring devices 10, 11 are combined to form a vertical measuring beam, which is located on a measuring point 13 fixed relative to the reactor housing 1 on the surface of the substrate 7 or of the susceptor 4. With the measuring devices 10, 11, an emission value E and a reflectivity value R of the substrate surface are thus measured.
  • measured values can be determined with the measuring devices 10, 11 at measuring positions lying on a circular line L.
  • the determination of the emissivity value E by means of the Emiss foundedswert- Mes device 10 takes place at periodically successive times t 2 , t 4 (see Figure 6).
  • reflectivity values R are determined.
  • the measurement positions on the susceptor top side and in particular of the substrate surface on the line L are offset in the circumferential direction relative to one another.
  • the positions represented by an X in FIGS. 2 and 4 symbolize the measuring positions for the determination of the emissivity value and the positions shown with an open circle the measuring positions of the reflectivity value determination.
  • the substrates 7 can still rotate about a substrate axis of rotation. They lie on a substrate holder 6, which can rotate about this axis.
  • the line L represented in FIG. 2, on which the measuring positions lie, is therefore more complicated in terms of reality than shown in FIG. 2 for the sake of simplicity.
  • the line forms cycloids on the substrate surfaces.
  • the invention is based on the finding that the reflectivity values R, as shown in FIG. 5, change greatly in the region of the edge of the substrate 7 in a radial direction, relative to the center of the substrate. While the reflectivity values in the central region of the substrate 7 change only slightly along a line running through the center, the reflectivity values at the edge of the substrate change more strongly on a straight line through the diameter of the substrate. The differences between two measured values of the reflectivity determined at respectively equally spaced measuring positions are greater in the edge region than in the central region.
  • the lower curve in the figure 7 shows qualitatively spread the course of the reflectivity of the substrate surface in the radial direction, ie at a migrating over the substrate in the radial direction measuring point as a function of time.
  • the open circles denote the reflectivity values Ri, R 2 , R 3 , R 4 which were measured at the times ti, h, ts and t 7 .
  • emissivity values Ei, E 2 , E3 and E 4 have been measured at times t 2 , t 4 , t 6 , t s. It can be seen that a reflectivity value Ri used to correct for example the emissivity value Ei is too low and a measured value of the reflectivity R 2 used for the correction is too high.
  • an average value Rr or interpolated value is formed from the two adjacent measured values of the reflectivity Ri, R 2 , which is shown in FIG. 7 as a filled square.
  • the calculation of the reflectivity correction value R 2 'of the time to correct the emissivity value E 2 is determined by a quadratic interpolation.
  • the reflectivity values of the correction time point t4 immediately adjacent lying, at times t 3 and ts determined are not only R 2, and R 3 is used but also the reflectivity Ri and R 4, which have been determined at the times ti and t. 7
  • Temperature values Ti, T 2 , T 3 and T 4 which can be used to control the heater 5, can be determined by the correction of the emissivity value Ei, E 2 , E 3 , E 4 that has taken place in such an interpolatory manner.
  • the above explanations serve to explain the of the
  • the invention relates to inventions which have been recorded in their entirety and that independently further develop the state of the art, at least by the following combinations of features, whereby two, several or all of these combinations of features can also be combined, namely: A method or a device, which are characterized in that an emissivity value Ei and a plurality of reflectivity values Ri, Ri + i measured at different times ti, ti + i are used to calculate the temperature value Ti.
  • a method for measuring a surface temperature of a substrate 7 arranged on a susceptor 4 rotating about a rotation axis A wherein at a measuring point 13 spaced radially from the axis of rotation A, optical emissivity values Ei are arranged on the surface and phase-shifted in sequence optical reflectivity values Ri of the surface are measured and from each emissivity value (Ei) a temperature value corrected by the use of at least two reflectivity values Ri, Ri + i measured at different times ti, ti + i is calculated.
  • a method or a device characterized in that the use of the reflectivity values Ri, Ri + i comprises an averaging.
  • a method or a device which is characterized in that the points in time at which the reflectivity values Ri, Ri + i used for the correction are measured are immediately adjacent to the times at which the measurement of the emissivity worth egg.
  • a method or a device which are characterized in that the temperature measured value Ti is used to control a heater 5.
  • a method or a device which is characterized in that the measuring device (10) for measuring the emissivity value Ei is a pyrometer 10 and the measuring device (11) for measuring the reflectivity value Ri comprises an LED and a light detector.
  • a method or a device which are characterized in that the beam path of the two measuring devices 10, 11 is identical.
  • a CVD reactor which is characterized in that the evaluation device 15 is set up such that at least two reflectivity values Ri, Ri + i are used to calculate a temperature value Ti.
  • a method, a device or a CVD reactor which is characterized in that exactly one temperature value is calculated from exactly one emissivity value Ei using a plurality of reflectivity values Ri, Ri + i.
  • a measuring device which is characterized in that the training is W erte Hughes 15 set up so that for calculating a temperature turiness Ti least two reflectivity values Ri, Ri + i are used.

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Abstract

The invention relates to a method or a device for measuring a surface temperature of a substrate (7) arranged, radially offset with respect to an axis of rotation (A), on a susceptor (4) rotating about the axis of rotation (A), wherein a first optical reflectivity value (Ri) of the surface is measured at a first time (t1) at a measuring point (13) radially spaced from the axis of rotation (A), then an optical emissivity value (Ei) is measured at a second time (ti), and then a second optical reflectivity value (Ri+1) of the surface is measured at a third time (t3), wherein a temperature measurement value (Ti) is calculated from each emissivity value (Ei) and at least two reflectivity values (Ri, Ri+1) which have been measured at different times (ti, ti+1).

Description

Beschreibung  description
Vorrichtung und Verfahren zum Messen einer Oberflächentemperatur von auf einem drehenden Suszeptor angeordneten Substraten Apparatus and method for measuring a surface temperature of substrates disposed on a rotating susceptor
Gebiet der Technik Field of engineering
[0001] Die Erfindung betrifft ein Verfahren und eine Mess Vorrichtung zum Messen einer Oberflächentemperatur eines insbesondere radial versetzt zu ei- ner Drehachse auf einem um die Drehachse rotierenden Suszeptor angeordne- ten Substrates, wobei an einer radial von der Drehachse beabstandeten Mess- stelle zu einem ersten Zeitpunkt ein erster optischer Reflektivitätswert der Oberfläche, danach zu einem zweiten Zeitpunkt ein optischer Emissivitätswert und danach zu einem dritten Zeitpunkt ein zweiter optischer Reflektivitätswert der Oberfläche gemessen wird, wobei aus dem Emissivitätswert ein mit dem Reflektivitätswert korrigierter Temperatur-Messwert berechnet wird. [0001] The invention relates to a method and a measuring V orrichtung for measuring a surface temperature of an in particular radially offset relative to an axis of rotation on a rotating about the rotational axis susceptor angeordne- th substrate, wherein a position at a radial distance from the rotational axis measurement to a first optical reflectivity value of the surface is measured at a first time, then an optical emissivity value at a second time and then a second optical reflectivity value of the surface at a third time, wherein a temperature measured value corrected with the reflectivity value is calculated from the emissivity value.
[0002] Die Erfindung betrifft darüber hinaus einen CVD-Reaktor mit einem von einer Heizeinrichtung beheizbaren, von einer Drehantriebseinrichtung in eine Drehung um eine Drehachse bringbaren, eine Mehrzahl von insbesondere radial zur Drehachse versetzt angeordnete Substrataufnahmen zur Aufnahme von Substraten aufweisender Suszeptor, mit einer ortsfest zum Reaktorgehäuse radial versetzt zur Drehachse auf dem Suszeptor angeordneten Messstelle, mit einer optischen Emissionswert-Messeinrichtung und einer optischen Reflekti- onswert-Messeinrichtung, die eingerichtet sind, zu voneinander verschiedenen Zeiten an der Messstelle Emissivitäts werte und Reflektivitätswerte auf dem sich drehenden Suszeptor zu messen, und mit einer Auswerteeinrichtung, die aus dem mittels der Reflektivitätswerte korrigierten Emissivitäts werten Tempera- turwerte berechnet oder die aus den unkorrigierten Emissivitätswerten Roh- temperaturen berechnet, die mittels der gemessenen Reflektivitätswerte korri- giert werden. Stand der Technik The invention further relates to a CVD reactor with a heater heated by a rotary drive means in a rotation about a rotation axis, a plurality of particular radially offset to the rotational axis arranged substrate receptacles for receiving substrates having susceptor, with a stationary to the reactor housing radially offset from the axis of rotation on the susceptor arranged measuring point, with an optical emission value measuring device and an optical Reflecti- onswert-measuring device, which are adapted to measure mutually different times at the measuring point emissivity values and reflectivity values on the rotating susceptor, and with an evaluation device which calculates temperature values from the emissivity values corrected by means of the reflectivity values or which calculates raw temperatures from the uncorrected emissivity values which are corrected by means of the measured reflectivity values be. State of the art
[0003] Bei der Herstellung von dünnen Halbleiterschichten auf Substraten, insbesondere bei der Herstellung von GaN-Halbleitertransistoren wird die Oberflächentemperatur mittels Pyrometern ermittelt. Mit den Oberflächentem- peraturen kann eine Heizung geregelt werden, mit der der Suszeptor, der die Substrate trägt, auf eine Prozesstemperatur aufgeheizt wird. Das Ziel besteht darin, eine möglichst gleichförmige Temperaturverteilung auf der Substratober- fläche zu erreichen, selbst wenn sich das Substrat während der thermischen Behandlung leicht verbiegt. Bei der Verbiegung kann ein radial ungleichmäßi- ger Kontakt des Substrates zur Auflagefläche Temperatur-Inhomogenitäten bewirken. Bei einer Mehrzonenheizung mit in Radialrichtung verschiedenen Umfangs-Heizeinrichtungen können verschiedene Radialbereiche des Suszep- tors unterschiedlich beheizt werden. Bei sich drehenden Substraten auf einem sich drehenden Substratträger können so die Randbereiche des Substrates an- ders beheizt werden, als ein Zentralbereich des Substrates. Ein auf eine Verbie- gung des Substrates zurückzuführendes unterschiedliches Wärmetransportver- halten vom Suszeptor zum Substrat kann dadurch ausgeglichen werden. Es ist aber auch möglich, bewusst ein radial nach außen ansteigendes Temperatur- profil zu erzeugen, um beispielsweise Zugspannungen in einem Siliziumwafer in Umfangsrichtung aufgrund der thermischen Ausdehnung des Wafers in der Mitte auszu gleichen. Der Durchmesser eines typischen Wafers beträgt 200 mm. In the production of thin semiconductor layers on substrates, in particular in the production of GaN semiconductor transistors, the surface temperature is determined by means of pyrometers. The surface temperatures can be used to control a heating with which the susceptor carrying the substrates is heated to a process temperature. The goal is to achieve the most uniform possible temperature distribution on the substrate surface, even if the substrate bends slightly during the thermal treatment. During bending, a radially uneven contact of the substrate with the bearing surface can cause temperature inhomogeneities. In a multi-zone heating with radially different circumferential heaters, different radial areas of the susceptor can be heated differently. With rotating substrates on a rotating substrate carrier, the edge regions of the substrate can be heated differently than a central region of the substrate. A different heat transport behavior attributable to a bending of the substrate from the susceptor to the substrate can thereby be compensated. However, it is also possible to intentionally generate a temperature profile rising radially outward in order, for example, to compensate for tensile stresses in a silicon wafer in the circumferential direction due to the thermal expansion of the wafer in the middle. The diameter of a typical wafer is 200 mm.
[0004] Ein Ziel des erfindungs gemäßen Verfahrens ist die Herstellung von GaN / AlGaN-Strukturen auf Silizium. Als Anwendung kommt aber auch die Herstellung aller Arten von opto-elektronischen Bauelementen basierend auf der GaN-Technologie, wie auch GaAs oder InP-Technologie in Frage, bei- spielsweise die Herstellung von Lasern, Detektoren, Leuchtdioden, Solarzellen oder sonstigen dielektrischen Schichten. Wesentlich ist die Abscheidung von dünnen, relativ gleichförmigen Schichten. Während das Substrat, beispielsweise Siliziumsubstrat, für die Wellenlänge des Pyrometers intransparent ist, sind die zuvor bezeichneten Schichten für die Wellenlänge des Pyrometers in der Regel semitransparent. An object of the inventive method is the production of GaN / AlGaN structures on silicon. As an application, however, it is also possible to manufacture all types of optoelectronic components based on GaN technology, as well as GaAs or InP technology, for example the production of lasers, detectors, light-emitting diodes, solar cells or other dielectric layers. Essential is the deposition of thin, relatively uniform layers. While the substrate, for example Silicon substrate, for the wavelength of the pyrometer is intransparent, the previously designated layers for the wavelength of the pyrometer are usually semitransparent.
[0005] Bei der Temperaturmessung wird die spektrale Strahlungsintensität gemessen, die vom Messobjekt, also der Substratoberfläche oder von der Ober- fläche des Suszeptors ausgeht. Gemäß dem Planck' sehen Strahlungsgesetz kann jeder Strahlungsintensität eine Temperatur zugeordnet werden. Eine eindeutige Temper aturzuordnung setzt aber voraus, dass sich die Reflektivität der In the temperature measurement, the spectral radiation intensity is measured, which starts from the measurement object, ie the substrate surface or from the surface of the susceptor. According to Planck's law of radiation, each radiation intensity can be assigned a temperature. However, a clear allocation of temperature presupposes that the reflectivity of the
Schichtoberfläche nicht ändert. Letztere hängt mit der Emissivität nach dem Kirchhoff'schen Gesetz r=1-e zusammen. Wegen der Semitransparenz der Schichten und einer Schichtdicke, die ungefähr in der Größenordnung der Wel- lenlänge zur Emissionswert-Bestimmung liegt, ändert sich jedoch die Oberflä- chen-Emissivität beziehungsweise die Oberflächen-Reflektivität während des Schichtwachstums stark. Um diese systematischen Änderungen zu berücksich- tigen, wird nicht nur ein Emissivitäts-Messwert, sondern auch ein Reflektivi- täts-Messwert bestimmt. Dies erfolgt mittels zweier voneinander verschiedener Messeinrichtungen, beispielsweise mit einem Pyrometer zur Ermittlung des Emissivitäts wertes und einer Lichtquelle und einem Lichtdetektor zur Ermitt- lung des Reflektivitäts wertes. Die Lichtquelle kann eine Leuchtdiode oder ein Laser sein. Der Lichtdetektor kann ein Fotosensor oder Fototransistor sein. Die Reflektivitätsmessung erfolgt bei derselben Messwellenlänge von beispielswei- se 880 nm bis 950 nm, bei der auch die Emissivitätswert-Ermittlung erfolgt. Aus dem Emissivitätswert kann ein Rohtemperaturwert bestimmt werden, der unter Verwendung des Reflektivitäts wertes korrigiert wird. Auf diese Weise kann der Fabry-Perot-Effekt kompensiert werden. Die Emissivitätswert-Bestimmung und die Reflektivitätswert-Bestimmung sollen optimalerweise an derselben Stelle des Messobjektes erfolgen. In der Realität ist dies jedoch nicht möglich, da die Messungen alternierend durchgeführt werden, um eine gegenseitige Beeinflus- sung zu vermeiden. So ist beispielsweise vorgesehen, in Pulsen von etwa 100Hz den Emissionswert an einer - bezogen auf das Reaktorgehäuse - ortsfesten Messstelle auf dem sich drehenden Suszeptor zu ermitteln. In den Pulspausen erfolgt dann phasenversetzt dazu die Ermittlung der Reflektivität der Oberflä- che des Messobjektes. Da sich der Suszeptor während der Messung dreht und die Messstelle beispielsweise 200 mm versetzt zur Drehachse liegt, wandert die Messposition am Messobjekt vom Zeitpunkt der Messung des Emissivitätswer- tes zum Zeitpunkt der Messung des Reflektivitätswertes etwa um 1 bis 2 mm weiter. Dies hat zur Folge, dass der gemessene Emissionswert örtlich nicht mit dem gemessenen Reflektivitätswert korreliert. Gleichwohl wird beim Stand der Technik dieser Reflektivitätswert verwendet, um die aus dem Emissivitätswert gewonnene Rohtemperatur zu korrigieren. Hinsichtlich der Einzelheiten des beschriebenen Messverfahrens wird auf W. G. Breiland,„Reflectance- Correcting Pyrometry in Thin Film Deposition Applications" 2003 (approved for public release) verwiesen. Layer surface does not change. The latter is related to emissivity according to Kirchhoff's law r = 1-e. However, because of the semitransparency of the layers and a layer thickness which is approximately on the order of the wavelength for determining the emission value, the surface emissivity or the surface reflectivity changes greatly during the layer growth. In order to take these systematic changes into account, not only an emissivity measurement, but also a reflectivity measurement is determined. This is done by means of two mutually different measuring devices, for example, with a pyrometer to determine the emissivity value and a light source and a light detector for determining the reflectivity value. The light source may be a light emitting diode or a laser. The light detector may be a photosensor or phototransistor. The reflectivity measurement takes place at the same measuring wavelength of, for example, 880 nm to 950 nm, at which the emissivity value determination is also carried out. From the emissivity value, a raw temperature value can be determined which is corrected using the reflectivity value. In this way, the Fabry-Perot effect can be compensated. The emissivity value determination and the reflectivity value determination should ideally take place at the same location of the measurement object. In reality, however, this is not possible because the measurements are performed alternately to avoid mutual interference. For example, in pulses of about 100Hz To determine the emission value at a - fixed relative to the reactor housing - fixed measuring point on the rotating susceptor. In the pulse pauses, the determination of the reflectivity of the surface of the measurement object is then performed phase-shifted. Since the susceptor rotates during the measurement and the measuring point is, for example, offset by 200 mm from the axis of rotation, the measuring position on the measuring object moves by about 1 to 2 mm from the time of measuring the emissivity value at the time of measuring the reflectivity value. This has the consequence that the measured emission value does not locally correlate with the measured reflectivity value. However, in the prior art, this reflectivity value is used to correct the raw temperature obtained from the emissivity value. For details of the described measurement method, reference is made to WG Breiland, "Reflectance-Correcting Pyrometry in Thin Film Deposition Applications" 2003 (approved for public release).
[0006] Aus der US 5,326,173 , US 6,349,270 und US 2016/0282188 Al sind Vor- richtungen und Verfahren zur Messung der Temperatur eines sich drehenden Substrates bekannt. In zeitlicher Aufeinanderfolge wird an der Substratoberflä- che unter Verwendung von Pyrometern und Lichtquellen Reflektions werte und Emissionswerte gewonnen, aus denen Temperaturen berechnet werden. [0006] Devices and methods for measuring the temperature of a rotating substrate are known from US Pat. Nos. 5,326,173, 6,349,270 and US 2016/0282188 A1. In temporal succession, reflection values and emission values are obtained on the substrate surface using pyrometers and light sources, from which temperatures are calculated.
[0007] Die US 2008/0036997 Al beschreibt ein Verfahren zum Messen von Re- flektionswerten an sich drehenden Substraten. Die Messzeiten werden mit den Drehzeiten des Substrates synchronisiert, sodass die Messvorrichtung zeitlich aufeinanderfolgende Messwerte liefert, die von derselben Stelle des Substrates zugeordnet sind. [0007] US 2008/0036997 A1 describes a method for measuring reflection values on rotating substrates. The measurement times are synchronized with the rotation times of the substrate, so that the measuring device supplies time-sequential measured values which are assigned from the same location of the substrate.
[0008] Die US 2006/0171442 Al beschreibt ein Verfahren zum Kalibrieren ei- nes Pyrometers. [0009] Die US 2012/ 0293813 Al beschreibt ein Verfahren zur Messung von Reflektionswerten an einer Substratoberfläche. [0008] US 2006/0171442 A1 describes a method for calibrating a pyrometer. US 2012/0293813 Al describes a method for measuring reflection values on a substrate surface.
[0010] Das bisher betriebene Messverfahren führt insbesondere an Messpositi- onen, die am Rand des Substrates liegen, zu fehlerhaften Temperaturwerten. [0010] The previously operated measuring method leads to erroneous temperature values, in particular at measuring positions which lie at the edge of the substrate.
Zusammenfassung der Erfindung Summary of the invention
[0011] Der Erfindung liegt die Aufgabe zugrunde, das gattungs gemäße Ver- fahren hinsichtlich der Temperaturbestimmung zu verbessern und eine diesbe- züglich ausgebildete Vorrichtung anzugeben. Gelöst wird die Aufgabe durch die in den Ansprüchen angegebene Erfindung, wobei die Unteransprüche nicht nur vorteilhafte Weiterbildungen der in den nebengeordneten Ansprüchen an- gegebenen Erfindung, sondern auch eigenständige Lösungen der Aufgabe dar- stellen. [0011] The invention is based on the object of improving the generic method with regard to the determination of temperature and of specifying a device designed for this purpose. The object is achieved by the invention specified in the claims, wherein the subclaims represent not only advantageous developments of the invention disclosed in the independent claims, but also independent solutions to the problem.
[0012] Während beim Stand der Technik zur Korrektur des Emis sions wertes jeweils genau ein Reflektivitätswert verwendet wird, wird erfindungsgemäß vorgeschlagen, dass mehrere, zu verschiedenen Zeiten gemessene Reflektivi- tätswerte zur Korrektur insbesondere genau eines Emis sivitäts wertes verwen- det werden. So wird insbesondere vorgeschlagen, dass periodisch aufeinander- folgend Emis sivitäts werte und phasenversetzt dazu Reflektivitätswerte gemes- sen werden. Aus bevorzugt jedem Emissivitätswert wird eine Rohtemperatur berechnet. Diese wird durch die Verwendung von zumindest zwei Reflektivi- tätswerten, die an zwei verschiedenen Zeitpunkten gemessen werden, korri- giert. Die Korrektur kann dabei durch die Bildung eines Mittelwertes zwischen den beiden Reflektivitäts-Messwerten erfolgen. Bevorzugt wird ein erster Re- flektivitäts-Messwert zeitlich vor dem Emissivitätswert und ein zweiter Reflek- tivitätswert zeitlich nach dem Emissivitätswert ermittelt. Es kann der Mittel- wert dieser beiden Reflektivitätswerte gebildet werden, um eine aus dem Emis- sivitätswert, der zu einem Zeitpunkt zwischen den beiden Zeitpunkten, an de- nen die Reflektivitätswerte ermittelt werden, gemessen wird, gewonnene Roh- temperatur zu korrigieren. Es kann sich auch um eine gewichtete Mittelwert- bildung handeln. Die beiden Zeitpunkte zur Ermittlung der zur Korrektur ver- wendeten Reflektivitätswerte sind dem Zeitpunkt der Emissivitätswert- Ermittlung bevorzugt unmittelbar zeitlich benachbart. Die Berech- nung/ Korrekturwertbildung kann durch eine lineare Interpolation oder durch eine Interpolation höherer Ordnung zwischen mehreren zeitlich unmittelbar aufeinanderfolgend aufgenommenen Reflektivitäts-Mess werten erfolgen. Der mit den zuvor beschriebenen Verfahren gewonnene Temper aturwert kann zur Regelung der der Heizung verwendet werden. While precisely one reflectivity value is used in each case for correcting the emission value in the prior art, it is proposed according to the invention that a plurality of reflectivity values measured at different times be used to correct in particular exactly one emissivity value. For example, it is proposed in particular that periodically successive emissivity values and phase-shifted reflectivity values are measured. From preferred each emissivity value, a raw temperature is calculated. This is corrected by the use of at least two reflectivity values, which are measured at two different points in time. The correction can be effected by the formation of an average value between the two reflectivity measured values. Preferably, a first reflectivity measurement value is determined temporally before the emissivity value and a second reflectivity value is determined temporally after the emissivity value. The average value of these two reflectivity values can be formed in order to obtain one from the emis- value that is measured at a point in time between the two instants at which the reflectivity values are determined, to correct the raw temperature obtained. It can also be a weighted averaging. The two times for determining the reflectivity values used for the correction are preferably immediately adjacent to the time of the determination of the emissivity value. The calculation / correction value formation can be carried out by means of a linear interpolation or by a higher-order interpolation between a plurality of reflectivity measurement values taken in temporally immediately successive fashion. The temperature value obtained by the methods described above can be used to control the heating.
[0013] Ein erfindungsgemäßer CVD-Reaktor besitzt einen von einer Heizein- richtung beheizbaren Suszeptor. Der Suszeptor kann sich um eine Vertikalachse drehen. Hierzu ist eine Drehantriebseinrichtung vorgesehen, die einen Schaft des Suszeptors dreht, um den fest mit dem Schaft verbundenen Suszeptor in eine Drehung um die Antriebsachse zu bringen. Die Heizeinrichtung ist bevor- zugt unterhalb des Suszeptors angeordnet. Es kann sich um eine RF-Heizung, eine IR-Heizung oder eine anderweitige Heizung handeln. Auf der von der Heizung wegweisenden Oberseite des Suszeptors sind mehrere Substratauf- nahmen vorgesehen. Die Substrataufnahmen können Vertiefungen in der Ober- seite des Suszeptors sein, in denen ein Substrat einliegt. Sie können aber auch Vorsprünge zur Lagejustierung sein. Die Substrataufnahmen sind bevorzugt radial versetzt zur Drehachse angeordnet, so dass die sie auf dem Suszeptor fixierenden Substrate außermittig des Substrates angeordnet sind. Oberhalb des Substrates befindet sich eine Prozesskammer, die nach oben durch eine Pro- zesskammerdecke begrenzt ist. Es ist ein Gaseinlassorgan vorgesehen, mit dem Prozessgase, beispielsweise Hydride der V-Hauptgruppe und metallorganische Verbindungen der III-Hauptgruppe in die Prozesskammer eingespeist werden. Das Einspeisen der Prozessgase erfolgt bevorzugt zusammen mit einem Trä- gergas, beispielsweise Wasserstoff. Das Gaseinlassorgan kann im Zentrum der Prozesskammer angeordnet sein. Es kann sich aber auch duschkopfartig über die gesamte Decke der Prozesskammer erstrecken. Es sind zwei Messeinrich- tungen vorgesehen: Eine erste Messeinrichtung, mit der ein Emissivitätsmess- wert und eine zweite Messeinrichtung, mit der ein Reflektivitätswert an einer Messposition der Oberfläche des Substrates beziehungsweise des Suszeptors ermittelt werden kann. Es handelt sich bevorzugt um optische Messeinrichtun- gen, beispielsweise Pyrometer, Fototransistoren oder Fotodioden. Zur Emissivi- tätsmessung kann darüber hinaus eine Lichtquelle verwendet werden. Über beispielsweise einen Strahlteiler kann erreicht werden, dass beide optische Messeinrichtungen denselben Strahlengang besitzen, der bevorzugt parallel zur Drehachse gerichtet ist. Die Messung kann durch die Prozesskammerdecke hindurch erfolgen. Letztere besitzt hierzu bevorzugt eine Öffnung. Der„Mess- strahl", der durch den Strahlengang bestimmt ist, trifft bevorzugt senkrecht an einer zum Reaktorgehäuse ortsfesten Messstelle auf den sich während der Mes- sung drehenden Suszeptor, so dass, bezogen auf das sich drehende Bezugssys- tem des Suszeptors, die Messstelle auf einer Kreisbahn um das Drehzentrum des Suszeptors wandert. Mit den Messeinrichtungen werden somit mehrere, auf einer Kreisbogenlinie um das Drehzentrum des Suszeptors in Umfangsrich- tung voneinander beabstandeten Messpositionen Messwerte ermittelt, wobei jeweils eine Emissivitäts-Messwertposition zwischen zwei Reflektivitäts- Messwertpositionen angeordnet sind. Die Messstelle kann um mehr als die Hälfte des Radius des Suszeptors in der Drehachse beabstandet sein. Die Kreis- bogenlinie (auf der sich die Messpositionen befinden) kann durch die Zentren der bevorzugt kreisrunden Substrate verlaufen. Die Kreisbogenlinie kann aber auch außerhalb der Zentren der Substrate verlaufen und insbesondere durch die Ränder der Substrate hindurchgehen. Es kann vorgesehen sein, dass mehre- re Sensorpaare in unterschiedlichen Radialabständen vorgesehen sind, wobei jedes Sensorpaar einen Sensor zur Emissivitätswertbestimmung und einen Sen- sor zur Reflektivitätswertbestimmung aufweist. Die erfindungs gemäße Vor- richtung weist eine Auswerteeinrichtung auf, mit der aus den Emissivitätswer- ten Rohtemperatur-Messwerte ermittelt werden. Zu jedem Emissivitätswert wird eine Rohtemperatur ermittelt. Diese wird unter Verwendung zumindest zweier Reflektivitäts-Messwerte, die an voneinander verschiedenen Messposi- tionen auf dem sich drehenden Suszeptor ermittelt worden sind, ein Korrek- turwert gebildet, mit dem die Rohtemperatur zu einem Temper aturwert korri- giert wird. Die erfindungs gemäße Vorrichtung ist insbesondere eine Messvor- richtung zur Messung einer Oberflächentemperatur mit einer Auswerteeinrich- tung, die zur Ermittlung eines Temper aturwertes einen Emissivitätswert und zumindest zwei Reflektivitäts werte verwendet. An inventive CVD reactor has a susceptor which can be heated by a heating device. The susceptor can rotate about a vertical axis. For this purpose, a rotary drive device is provided which rotates a shaft of the susceptor to bring the firmly connected to the shaft susceptor in a rotation about the drive axis. The heating device is preferably arranged below the susceptor. It may be RF heating, IR heating or other heating. Several substrate receptacles are provided on the upper side of the susceptor pointing away from the heating. The substrate receptacles can be recesses in the upper side of the susceptor, in which a substrate rests. But they can also be projections for Lagejustierung. The substrate receptacles are preferably arranged radially offset from the axis of rotation, so that they are arranged on the susceptor fixing substrates off-center of the substrate. Above the substrate is a process chamber that is bounded above by a process chamber ceiling. A gas inlet element is provided, with which process gases, for example hydrides of the V main group and organometallic compounds of the III main group are fed into the process chamber. The feed of the process gases is preferably carried out together with a carrier. gergas, for example hydrogen. The gas inlet member may be disposed in the center of the process chamber. It can also extend in a shower head over the entire ceiling of the process chamber. Two measuring devices are provided: a first measuring device with which an emissivity measurement value and a second measuring device can be determined with which a reflectivity value at a measuring position of the surface of the substrate or of the susceptor can be determined. They are preferably optical measuring devices, for example pyrometers, phototransistors or photodiodes. In addition, a light source can be used to measure the emissivity. By way of example, a beam splitter can be achieved that both optical measuring devices have the same beam path, which is preferably directed parallel to the axis of rotation. The measurement can be made through the process chamber ceiling. The latter preferably has an opening for this purpose. The "measuring beam", which is determined by the beam path, preferably impinges perpendicularly on a measuring point fixed to the reactor housing on the susceptor rotating during the measurement, so that, based on the rotating reference system of the susceptor, the measuring point With the measuring devices, a plurality of measuring positions, which are circumferentially spaced from each other about the center of rotation of the susceptor, are thus determined, wherein in each case one emissivity measured value position is arranged between two reflectivity measured value positions The circular arc line (on which the measuring positions are located) can run through the centers of the preferably circular substrates, but the circular arc line can also extend outside the centers of the substrates and in particular by the di e edges of the substrates go through. It may be provided that a plurality of sensor pairs are provided at different radial distances, each sensor pair having a sensor for determining the emissivity value and a sensor for determining the reflectivity value. The fiction, contemporary preamble Direction has an evaluation device with which raw temperature measured values are determined from the emissivity values. For each emissivity value, a raw temperature is determined. This is formed by using at least two reflectivity measured values, which have been determined at mutually different measuring positions on the rotating susceptor, a correction value with which the raw temperature is corrected to a temperature value. The device according to the invention is, in particular, a measuring device for measuring a surface temperature with an evaluation device which uses an emissivity value and at least two reflectivity values to determine a temperature value.
Kurze Beschreibung der Zeichnungen Brief description of the drawings
[0014] Ausführungsbeispiele der Erfindung werden nachfolgend anhand bei- gefügter Zeichnungen erläutert. Es zeigen: Exemplary embodiments of the invention are explained below with reference to attached drawings. Show it:
Fig. 1 schematisch in einer Schnittdarstellung ein erstes Ausfüh- rungsbeispiel eines CVD-Reaktors zur Durchführung des erfin- dungs gemäßen Verfahrens, 1 is a schematic sectional view of a first embodiment of a CVD reactor for carrying out the method according to the invention;
Fig. 2 etwa gemäß der Schnittlinie II-II in Figur 1 eine Draufsicht auf den Suszeptor 4 darauf angeordneten Substraten 7, 2 is a top view of the susceptor 4 arranged thereon substrates 7, as shown in section line II-II in Figure 1,
Fig. 3 eine Darstellung gemäß Figur 1 eines zweiten Ausführungsbei- spiels, 3 shows a representation according to FIG. 1 of a second exemplary embodiment,
Fig. 4 eine Darstellung gemäß Figur 2 des zweiten Ausführungsbei- spiels, Fig. 5 in Form einer Kurve die über die Winkelposition gemessenen4 shows a representation according to FIG. 2 of the second exemplary embodiment, Fig. 5 in the form of a curve measured over the angular position
Reflektivitätswerte R entlang einer Linie L in den Figuren 2 und 4, Reflectivity values R along a line L in FIGS. 2 and 4,
Fig. 6 die zeitliche Abfolge der Messungen der Emissivitätswerte E und der Reflektivitätswerte R und 6 shows the time sequence of the measurements of the emissivity values E and the reflectivity values R and
Fig. 7 schematisch die zu verschiedenen Zeiten ti bis t7 gemessenen Fig. 7 shows schematically the measured at different times ti to t 7
Reflektivitätswerte R, Emissivitätswerte E und daraus berech- neten Temperaturen T.  Reflectivity values R, emissivity values E and calculated temperatures T.
Beschreibung der Ausführungsformen Description of the embodiments
[0015] Die in den Figuren 1 bis 4 dargestellten CVD-Reaktoren besitzen jeweils ein Reaktorgehäuse 1, eine darin angeordnete Heizung 5, einem oberhalb der Heizung 5 angeordneten Suszeptor 4 und ein Gaseinlassorgan 2 zum Einleiten von beispielsweise TMGa, TMA1, NH3 AsHi, PHi und H2. Der Suszeptor 4 wird mit Hilfe einer Drehantriebseinrichtung 14 um eine vertikale Drehachse A drehangetrieben. Eine Antriebswelle 9 ist hierzu einerseits mit der Drehan- triebseinrichtung 14 und andererseits mit der Unterseite des Suszeptors 4 ver- bunden. The CVD reactors shown in Figures 1 to 4 each have a reactor housing 1, a heater 5 disposed therein, a arranged above the heater 5 susceptor 4 and a gas inlet member 2 for introducing, for example TMGa, TMA1, NH 3 AsHi, PHi and H 2 . The susceptor 4 is driven in rotation about a vertical axis of rotation A by means of a rotary drive device 14. For this purpose, a drive shaft 9 is connected, on the one hand, to the rotary drive device 14 and, on the other hand, to the underside of the susceptor 4.
[0016] Auf der von der Heizung 5 wegweisenden horizontalen Oberfläche des Suszeptors 4 liegen Substrate 7 auf. Die Substrate 7 liegen radial außerhalb der Drehachse A und werden von Substrataufnahmen in Position gehalten, die von einer Abdeckung 8 oder von einem Substrathalter 6 gebildet sind. On the groundbreaking of the heater 5 horizontal surface of the susceptor 4 are substrates 7. The substrates 7 are located radially outside the axis of rotation A and are held in position by substrate holders which are formed by a cover 8 or by a substrate holder 6.
[0017] Es sind zwei Messeinrichtungen vorgesehen, eine Emissions- Messeinrichtung 10, die von einem Pyrometer gebildet wird, welches den Emissivitätswert misst. Eine zweite Messeinrichtung 11 ist ebenfalls eine opti- sehe Messeinrichtung. Sie besitzt einen Lichtdetektor und eine Lichtquelle. Die Lichtquelle kann ein Laser sein. Der Lichtdetektor ein Fototransistor. Mit dieser Reflektionswert-Messeinrichtung 11 wird der Reflektivitätswert gemessen. Mit den beiden Messeinrichtungen 10, 11 können erfindungsgemäß Emissivitäts- werte und Reflektivitäts werte gewonnen werden. Über einen Strahl teiler 12 sind die„Messstrahlen" der beiden Messeinrichtungen 10, 11 zu einem vertika- len Messstrahl zusammengefasst, der an einer - bezogen auf das Reaktorgehäu- se 1 - ortsfesten Messstelle 13 auf die Oberfläche des Substrates 7 beziehungs- weise des Suszeptors 4 trifft. Mit den Messeinrichtungen 10, 11 wird somit ein Emissionswert E und ein Reflektivitätswert R der Substratoberfläche gemessen. There are provided two measuring devices, an emission measuring device 10, which is formed by a pyrometer, which measures the emissivity value. A second measuring device 11 is likewise an optimal see measuring device. It has a light detector and a light source. The light source may be a laser. The light detector is a phototransistor. With this reflection value measuring device 11, the reflectivity value is measured. With the two measuring devices 10, 11 emissivity values and reflectivity values can be obtained according to the invention. Via a beam splitter 12, the "measuring beams" of the two measuring devices 10, 11 are combined to form a vertical measuring beam, which is located on a measuring point 13 fixed relative to the reactor housing 1 on the surface of the substrate 7 or of the susceptor 4. With the measuring devices 10, 11, an emission value E and a reflectivity value R of the substrate surface are thus measured.
[0018] Da sich der Suszeptor 4 während der Messung um die Drehachse A dreht, können mit den Messeinrichtungen 10, 11 an auf einer Kreislinie L lie- genden Messpositionen Messwerte ermittelt werden. Since the susceptor 4 rotates about the axis of rotation A during the measurement, measured values can be determined with the measuring devices 10, 11 at measuring positions lying on a circular line L.
[0019] Die Ermittlung des Emissivitäts wertes E mittels der Emissivitätswert- Mes seinrichtung 10 erfolgt zu periodisch aufeinander folgenden Zeitpunkten t2, t4 (siehe Figur 6). Zu den Zeitpunkten ti, h, ts, die zwischen zwei Zeitpunkten t2, t4 liegen, an denen Emissivitätswerte bestimmt werden, werden Reflektivitäts- werte R bestimmt. Als Folge dieser Phasenverschiebung zwischen Emissivi- tätswert-Bestimmung und Reflektivitätswert-Bestimmung liegen die Messposi- tionen auf der Suszeptoroberseite und insbesondere der Substratoberfläche auf der Linie L in Umfangsrichtung versetzt zueinander. Beispielsweise symbolisie- ren die in den Figuren 2 und 4 mit einem X dargestellten Positionen die Mess- positionen für die Emissivitätswert-Bestimmung und die mit einem offenen Kreis dargestellten Positionen die Messpositionen der Reflektivitätswert- Bestimmung. [0020] Bei dem in der Figur 1 dargestellten CVD-Reaktor können sich die Sub- strate 7 noch um eine Substrat-Drehachse drehen. Sie liegen hierzu auf einem Substrathalter 6, der sich um diese Achse drehen kann. Die in der Figur 2 dar- gestellte Linie L, auf der die Messpositionen liegen, ist demzufolge in der Reali- tät komplizierter, als in der Figur 2 der Einfachheit halber dargestellt ist. Die Linie bildet auf den Substratoberflächen Zykloiden aus. The determination of the emissivity value E by means of the Emissivitätswert- Mes device 10 takes place at periodically successive times t 2 , t 4 (see Figure 6). At the times ti, h, ts which lie between two times t 2 , t 4 at which emissivity values are determined, reflectivity values R are determined. As a consequence of this phase shift between emissivity value determination and reflectivity value determination, the measurement positions on the susceptor top side and in particular of the substrate surface on the line L are offset in the circumferential direction relative to one another. For example, the positions represented by an X in FIGS. 2 and 4 symbolize the measuring positions for the determination of the emissivity value and the positions shown with an open circle the measuring positions of the reflectivity value determination. In the case of the CVD reactor shown in FIG. 1, the substrates 7 can still rotate about a substrate axis of rotation. They lie on a substrate holder 6, which can rotate about this axis. The line L represented in FIG. 2, on which the measuring positions lie, is therefore more complicated in terms of reality than shown in FIG. 2 for the sake of simplicity. The line forms cycloids on the substrate surfaces.
[0021] Der Erfindung liegt die Erkenntnis zugrunde, dass sich die Reflektivi- tätswerte R, wie in der Figur 5 dargestellt ist, im Bereich des Randes des Sub- strates 7 in einer Radialrichtung - bezogen auf die Mitte des Substrates - stark ändern. Während die Reflektivitätswerte im Zentralbereich des Substrates 7 sich entlang einer durch das Zentrum verlaufenden Linie nur geringfügig än- dert, ändern sich die Reflektivitätswerte am Rand des Substrates auf einer ge- raden Linie durch den Durchmesser des Substrates stärker. Die Differenzen zweier an jeweils gleich beabstandeten Messpositionen ermittelter Messwerte der Reflektivität sind im Randbereich größer als im Zentralbereich. The invention is based on the finding that the reflectivity values R, as shown in FIG. 5, change greatly in the region of the edge of the substrate 7 in a radial direction, relative to the center of the substrate. While the reflectivity values in the central region of the substrate 7 change only slightly along a line running through the center, the reflectivity values at the edge of the substrate change more strongly on a straight line through the diameter of the substrate. The differences between two measured values of the reflectivity determined at respectively equally spaced measuring positions are greater in the edge region than in the central region.
[0022] Die untere Kurve in der Figur 7 zeigt qualitativ gespreizt den Verlauf der Reflektivität der Substratoberfläche in Radialrichtung, also bei einer über das Substrat in Radialrichtung wandernden Messstelle in Abhängigkeit von der Zeit. Mit den offenen Kreisen sind die Reflektivitätswerte Ri, R2, R3, R4 bezeich- net, die zu den Zeiten ti, h, ts und t7 gemessen worden sind. Zwischen diesen Zeiten sind an den Zeiten t2, t4, t6, ts jeweils Emissivitätswerte Ei, E2, E3 und E4 gemessen worden. Es ist erkennbar, dass ein zur Korrektur beispielsweise des Emissivitäts wertes Ei verwendeter Reflektivitätswert Ri zu niedrig und ein zur Korrektur verwendeter Messwert der Reflektivität R2 zu hoch ist. Erfindungs- gemäß wird aus den beiden benachbarten Messwerten der Reflektivität Ri, R2 ein Mittelwert Rr beziehungsweise interpolierter Wert gebildet, der in der Fi- gur 7 als gefülltes Quadrat dargestellt ist. Zur Ermittlung eines für die Korrek- tur verwendeten Reflektivitätswertes der Zeit t6 zur Korrektur des Emissivi- tätswertes E3 kann ebenfalls ein interpolierter Wert oder Mittelwert verwendet werden, wobei hierzu der Mittelwert der Reflektivitätswerte R3 und R4 ver- wendet wird. Auch der Korrekturwert R4' kann durch Mittelwertbildung be- rechnet werden. The lower curve in the figure 7 shows qualitatively spread the course of the reflectivity of the substrate surface in the radial direction, ie at a migrating over the substrate in the radial direction measuring point as a function of time. The open circles denote the reflectivity values Ri, R 2 , R 3 , R 4 which were measured at the times ti, h, ts and t 7 . Between these times, emissivity values Ei, E 2 , E3 and E 4 have been measured at times t 2 , t 4 , t 6 , t s. It can be seen that a reflectivity value Ri used to correct for example the emissivity value Ei is too low and a measured value of the reflectivity R 2 used for the correction is too high. According to the invention, an average value Rr or interpolated value is formed from the two adjacent measured values of the reflectivity Ri, R 2 , which is shown in FIG. 7 as a filled square. In order to determine one for the correc- For the reflectivity value of the time t 6 used for the correction of the emissivity value E 3, it is likewise possible to use an interpolated value or mean value, the mean value of the reflectivity values R 3 and R 4 being used for this purpose. The correction value R4 'can also be calculated by averaging.
[0023] Die Berechnung des Reflektivitäts-Korrekturwertes R2' der Zeit zur Korrektur des Emissivitäts wertes E2 wird durch eine quadratische Interpolation ermittelt. Hierzu werden nicht nur die den Korrekturzeitpunkt t4 unmittelbar benachbart liegenden, zu den Zeiten t3 und ts ermittelten Reflektivitätswerte R2 und R3 verwendet, sondern auch die Reflektivitätswerte Ri und R4, die zu den Zeiten ti und t7 ermittelt worden sind. The calculation of the reflectivity correction value R 2 'of the time to correct the emissivity value E 2 is determined by a quadratic interpolation. For this purpose, the reflectivity values of the correction time point t4 immediately adjacent lying, at times t 3 and ts determined are not only R 2, and R 3 is used but also the reflectivity Ri and R 4, which have been determined at the times ti and t. 7
[0024] Durch die derart interpolatorisch erfolgte Korrektur des Emissivitäts- wertes Ei, E2, E3, E4 können Temperaturwerte Ti, T2, T3 und T4 ermittelt werden, die zur Regelung der Heizung 5 verwendet werden können. [0025] Die vorstehenden Ausführungen dienen der Erläuterung der von derTemperature values Ti, T 2 , T 3 and T 4 , which can be used to control the heater 5, can be determined by the correction of the emissivity value Ei, E 2 , E 3 , E 4 that has taken place in such an interpolatory manner. The above explanations serve to explain the of the
Anmeldung insgesamt erfassten Erfindungen, die den Stand der Technik zu- mindest durch die folgenden Merkmalskombinationen jeweils auch eigenstän- dig weiterbilden, wobei zwei, mehrere oder alle dieser Merkmalskombinatio- nen auch kombiniert sein können, nämlich: [0026] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass zur Berechnung des Temper aturwertes Ti ein Emissivitätswert Ei und mehrere zu verschiedenen Zeiten ti, ti+i gemessene Reflektivitätswerte Ri, Ri+i verwendet werden. [0027] Ein Verfahren zum Messen einer Oberflächentemperatur eines auf ei- nem um eine Drehachse A rotierenden Suszeptors 4 angeordneten Substrates 7, wobei an einer radial von der Drehachse A beabstandeten Messstelle 13 perio- disch aufeinanderfolgend optische Emissivitäts werte Ei an der Oberfläche und phasenversetzt dazu optische Reflektivitätswerte Ri der Oberfläche gemessen werden und aus jedem Emissivitätswert (Ei) ein durch die Verwendung zu- mindest zweier zu verschiedenen Zeitpunkten ti, ti+i gemessener Reflektivi- tätswerten Ri, Ri+i korrigierter Temper aturwert berechnet wird. The invention relates to inventions which have been recorded in their entirety and that independently further develop the state of the art, at least by the following combinations of features, whereby two, several or all of these combinations of features can also be combined, namely: A method or a device, which are characterized in that an emissivity value Ei and a plurality of reflectivity values Ri, Ri + i measured at different times ti, ti + i are used to calculate the temperature value Ti. [0027] A method for measuring a surface temperature of a substrate 7 arranged on a susceptor 4 rotating about a rotation axis A, wherein at a measuring point 13 spaced radially from the axis of rotation A, optical emissivity values Ei are arranged on the surface and phase-shifted in sequence optical reflectivity values Ri of the surface are measured and from each emissivity value (Ei) a temperature value corrected by the use of at least two reflectivity values Ri, Ri + i measured at different times ti, ti + i is calculated.
[0028] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass die Verwendung der Reflektivitätswerte Ri, Ri+i eine Mittelwertbildung umfasst. A method or a device, characterized in that the use of the reflectivity values Ri, Ri + i comprises an averaging.
[0029] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass die Mittelwertbildung eine gewichtete Mittelwertbildung ist. A method or apparatus characterized in that the averaging is a weighted averaging.
[0030] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass die Zeitpunkte, an denen die zur Korrektur verwendeten Reflektivitäts- werte Ri, Ri+i gemessen werden, zeitlich unmittelbar den Zeitpunkten benach- bart sind, an denen die Messung des Emissivitäts wertes Ei erfolgt. A method or a device, which is characterized in that the points in time at which the reflectivity values Ri, Ri + i used for the correction are measured are immediately adjacent to the times at which the measurement of the emissivity worth egg.
[0031] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass ein virtueller Reflektivitätswert berechnet wird, der durch eine lineare In- terpolation oder eine Interpolation höherer Ordnung der Reflektivitätswerte Ri, Ri+i, ... berechnet wird. A method or a device characterized in that a virtual reflectivity value is calculated, which is calculated by a linear interpolation or a higher-order interpolation of the reflectivity values Ri, Ri + i ,.
[0032] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass der Temperatur-Messwert Ti zur Regelung einer Heizung 5 verwendet wird. [0033] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass die Messeinrichtung (10) zur Messung des Emissivitätswertes Ei ein Pyro- meter 10 ist und die Messeinrichtung (11) zur Messung des Reflektivitätswertes Ri eine LED und einen Lichtdetektor umfasst. [0034] Ein Verfahren oder eine Vorrichtung, die dadurch gekennzeichnet sind, dass der Strahlengang der beiden Messeinrichtungen 10, 11 identisch ist. A method or a device, which are characterized in that the temperature measured value Ti is used to control a heater 5. [0033] A method or a device, which is characterized in that the measuring device (10) for measuring the emissivity value Ei is a pyrometer 10 and the measuring device (11) for measuring the reflectivity value Ri comprises an LED and a light detector. A method or a device, which are characterized in that the beam path of the two measuring devices 10, 11 is identical.
[0035] Ein CVD-Reaktor, der dadurch gekennzeichnet ist, dass die Auswer- teeinrichtung 15 so eingerichtet ist, dass zur Berechnung eines Temper aturwer- tes Ti mindestens zwei Reflektivitäts werte Ri, Ri+i verwendet werden. [0036] Ein Verfahren, eine Vorrichtung oder ein CVD-Reaktor, die dadurch gekennzeichnet sind, dass aus genau einem Emissivitätswert Ei unter Verwen- dung mehrerer Reflektivitätswerte Ri, Ri+i genau ein Temper aturwert berechnet wird. A CVD reactor, which is characterized in that the evaluation device 15 is set up such that at least two reflectivity values Ri, Ri + i are used to calculate a temperature value Ti. A method, a device or a CVD reactor, which is characterized in that exactly one temperature value is calculated from exactly one emissivity value Ei using a plurality of reflectivity values Ri, Ri + i.
[0037] Eine Messeinrichtung, die dadurch gekennzeichnet ist, dass die Aus- Werteeinrichtung 15 so eingerichtet ist, dass zur Berechnung eines Tempera- turwertes Ti mindestens zwei Reflektivitätswerte Ri, Ri+i verwendet werden. [0037] A measuring device, which is characterized in that the training is W erteeinrichtung 15 set up so that for calculating a temperature turwertes Ti least two reflectivity values Ri, Ri + i are used.
[0038] Alle offenbarten Merkmale sind (für sich, aber auch in Kombination untereinander) erfindungswesentlich. In die Offenbarung der Anmeldung wird hiermit auch der Offenbarungsinhalt der zugehörigen/beigefügten Prioritäts- unterlagen (Abschrift der Voranmeldung) vollinhaltlich mit einbezogen, auch zu dem Zweck, Merkmale dieser Unterlagen in Ansprüche vorliegender An- meldung mit aufzunehmen. Die Unteransprüche charakterisieren, auch ohne die Merkmale eines in Bezug genommenen Anspruchs, mit ihren Merkmalen eigenständige erfinderische Weiterbildungen des Standes der Technik, insbe- sondere um auf Basis dieser Ansprüche Teilanmeldungen vorzunehmen. Die in jedem Anspruch angegebene Erfindung kann zusätzlich ein oder mehrere der in der vorstehenden Beschreibung, insbesondere mit Bezugsziffern versehene und/ oder in der Bezugsziffernliste angegebene Merkmale aufweisen. Die Er- findung betrifft auch Gestaltungsformen, bei denen einzelne der in der vorste- henden Beschreibung genannten Merkmale nicht verwirklicht sind, insbeson- dere soweit sie erkennbar für den jeweiligen Verwendungszweck entbehrlich sind oder durch andere technisch gleichwirkende Mittel ersetzt werden kön- nen. All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure content of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of this application. The subclaims characterize, even without the features of a claimed claim, with their features independent inventive developments of the prior art, in particular in particular to make divisional applications based on these claims. The invention specified in each claim may additionally have one or more of the features described in the preceding description, in particular with reference numerals and / or given in the reference numerals. The invention also relates to design forms in which individual features mentioned in the above description are not realized, in particular insofar as they are identifiable for the respective intended use or can be replaced by other technically equivalent means.
Liste der Bezugszeichen List of reference numbers
1 Reaktorgehäuse R Reflektivitätswert1 reactor housing R reflectivity value
2 Gaseinlassorgan Ri Reflektivitätswert2 Gas inlet element Ri reflectivity value
3 Gaszuleitung Ri Reflektivitätswert3 Gas supply Ri reflectivity value
4 Suszeptor R2 Reflektivitätswert4 susceptor R 2 reflectivity value
5 Heizung R3 Reflektivitätswert5 heating R3 reflectivity value
6 Substrathalter R4 Reflektivitätswert6 Substrate holder R4 reflectivity value
7 Substrat T Temperatur 7 substrate T temperature
8 Abdeckung Ti Temperatur-Messwert 8 Cover Ti Temperature reading
9 Drehachse Ti Temperatur-Messwert9 Rotary axis Ti Temperature measured value
10 Emis sions wert- T2 Temperatur-Messwert Messeinrichtung T3 Temperatur-Messwert10 Emis sions wert- T 2 Temperature reading Measuring device T3 Temperature reading
11 Reflektionswert- T4 Temperatur-Messwert Messeinrichtung 11 Reflection value T 4 Temperature reading Measuring device
12 Strahlleiter  12 beam conductors
13 Messstelle  13 measuring point
14 Drehantriebseinrichtung  14 rotary drive device
ti Zeit  ti time
t2 Zeit t 2 time
A Drehachse t3 Zeit A rotation axis t 3 time
E Emis sivitäts wert t4 Zeit E Emis sivitätswert t 4 time
Ei Emis sivitäts wert ts Zeit  Egg's worth ts time
Ei Emis sivitäts wert t6 Zeit Egg emis- sity value t 6 time
E2 Emis sivitäts wert t7 Zeit E 2 Emissivity value t 7 Time
E3 Emis sivitäts wert ts Zeit  E3 Emis sivit worth ts time
E4 Emis sivitäts wert E 4 Emis sivitätswert
L Kreislinie  L circle line

Claims

Ansprüche claims
1. Verfahren oder Vorrichtung zum Messen einer Oberflächentemperatur eines auf einem um eine Drehachse (A) rotierenden Suszeptor (4) ange- ordneten Substrates (7), wobei an einer radial von der Drehachse (A) be- abstandeten Messstelle (13) zu einem ersten Zeitpunkt (ti) ein erster opti- scher Reflektivitätswert (Ri) der Oberfläche, danach zu einem zweiten1. Method or device for measuring a surface temperature of a substrate (7) arranged on a susceptor (4) rotating about an axis of rotation (A), wherein at a measuring point (13) spaced radially from the axis of rotation (A) First time (ti) a first optical reflectivity value (Ri) of the surface, then to a second
Zeitpunkt (t2) ein optischer Emissivitätswert (Ei) und danach zu einem dritten Zeitpunkt (t3) ein zweiter optischer Reflektivitätswert (R2) der Oberfläche gemessen wird, wobei aus jedem Emissivitätswert (Ei) ein mit dem Reflektivitätswert (Ri) korrigierter Temper aturwert (Ti) berechnet wird, dadurch gekennzeichnet, dass zur Berechnung des Temper aturwer- tes (Ti) ein Emissivitätswert (Ei) und mehrere zu verschiedenen Zeiten (ti, ti+i) gemessene Reflektivitätswerte (Ri, Ri+i) verwendet werden. Time (t 2 ) an optical emissivity value (Ei) and then at a third time (t3) a second optical reflectivity value (R 2 ) of the surface is measured, wherein from each emissivity value (Ei) with the Reflektivitätswert (Ri) corrected temperament value (Ti), characterized in that an emissivity value (Ei) and a plurality of reflectivity values (Ri, Ri + i ) measured at different times (ti, ti + i ) are used to calculate the temperature value (Ti).
2. Verfahren oder Vorrichtung zum Messen einer Oberflächentemperatur eines auf einem um eine Drehachse (A) rotierenden Suszeptor (4) ange- ordneten Substrates (7), wobei an einer radial von der Drehachse (A) be- abstandeten Messstelle (13) periodisch aufeinanderfolgend optische Emis- sivitätswerte (Ei) an der Oberfläche und phasenversetzt dazu optische Re- flektivitätswerte (Ri) der Oberfläche gemessen werden und aus jedem Emissivitätswert (Ei) ein durch die Verwendung zumindest zweier zu ver- schiedenen Zeitpunkten (ti, ti+i) gemessener Reflektivitätswerten (Ri, Ri+i) korrigierter Temper aturwert berechnet wird. 2. Method or device for measuring a surface temperature of a substrate (7) arranged on a susceptor (4) rotating about an axis of rotation (A), wherein at a measuring point (13) spaced radially from the axis of rotation (A), successive periods occur optical emissivity values (Ei) at the surface and out of phase with optical reflectivity values (Ri) of the surface are measured and from each emissivity value (Ei) a measured by the use of at least two at different times (ti, ti + i ) Reflectivity values (Ri, Ri + i ) corrected temperature value is calculated.
3. Verfahren oder Vorrichtung nach Anspruch 1 oder 2, dadurch gekenn- zeichnet, dass die Verwendung der Reflektivitätswerte (Ri, Ri+i) eine Mit- telwertbildung umfasst. 3. Method or device according to claim 1 or 2, characterized in that the use of the reflectivity values (Ri, Ri + i ) comprises an averaging.
4. Verfahren oder Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, dass die Mittelwertbildung eine gewichtete Mittelwertbildung ist. 4. A method or apparatus according to claim 3, characterized in that the averaging is a weighted averaging.
5. Verfahren oder Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Zeitpunkte, an denen die zur Korrektur verwendeten Reflektivitätswerte (Ri, Ri+i) gemessen werden, zeitlich un- mittelbar den Zeitpunkten benachbart sind, an denen die Messung des Emissivitäts wertes (Ei) erfolgt. 5. A method or device according to one of the preceding claims, characterized in that the times at which the reflectivity values used for the correction (Ri, Ri + i) are measured are immediately adjacent to the time points at which the measurement of the emissivity worth (egg) takes place.
6. Verfahren oder Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass ein virtueller Reflektivitätswert berechnet wird, der durch eine lineare Interpolation oder eine Interpolation höherer6. A method or device according to one of the preceding claims, characterized in that a virtual reflectivity value is calculated by a linear interpolation or an interpolation higher
Ordnung der Reflektivitätswerte (Ri, Ri+i, ...) berechnet wird. Order of the reflectivity values (Ri, Ri + i, ...) is calculated.
7. Verfahren oder Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Temperatur-Messwert (Ti) zur Rege- lung einer Heizung (5) verwendet wird. 7. Method or device according to one of the preceding claims, characterized in that the temperature measurement value (Ti) is used to control a heater (5).
8. Verfahren oder Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Messeinrichtung (10) zur Messung des Emissivitäts wertes (Ei) ein Pyrometer (10) ist und die Messeinrichtung (11) zur Messung des Reflektivitätswertes (Ri) eine LED und einen Lichtdetek- tor umfasst. 8. The method or apparatus according to any one of the preceding claims, characterized in that the measuring device (10) for measuring the emissivity value (Ei) is a pyrometer (10) and the measuring device (11) for measuring the Reflektivitätswertes (Ri) an LED and comprises a light detector.
9. Verfahren oder Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Strahlengang der beiden Messeinrich- tungen (10, 11) identisch ist. 9. Method or device according to one of the preceding claims, characterized in that the beam path of the two measuring devices (10, 11) is identical.
10. CVD-Reaktor mit einem von einer Heizeinrichtung (5) beheizbaren, von einer Drehantriebseinrichtung (14) in eine Drehung um eine Drehachse (A) bringbaren, eine Mehrzahl von insbesondere radial zur Drehachse (A) versetzt angeordneten Substrataufnahmen zur Fixierung von Substraten (7) aufweisender Suszeptor (4), mit einer ortsfest zum Reaktorgehäuse (1) radial versetzt zur Drehachse (A) auf dem Suszeptor (4) angeordneten Messstelle (13), mit einer optischen Emissionswert-Messeinrichtung (10) und einer optischen Reflektionswert-Messeinrichtung (11), die eingerich- tet sind, zu voneinander verschiedenen Zeiten (ti, ti+i) an der Messstelle (13) Emissivitäts werte (Ei) und Reflektivitätswerte (Ri, Ri+i) auf dem sich drehenden Suszeptor (4) zu messen, und mit einer Auswerteeinrichtung (15), die aus den Reflektivitätswerten (Ri, Ri+i) und den Emissivitäts werten (Ei) Temperaturwerte (Ti) berechnet, dadurch gekennzeichnet, dass die Auswerteeinrichtung (15) so eingerichtet ist, dass zur Berechnung eines Temper aturwertes (Ti) mindestens zwei Reflektivitätswerte (Ri, Ri+i) ver- wendet werden. 10. CVD reactor with one of a heating device (5) heated by a rotary drive device (14) in a rotation about a rotation axis (A) can be brought, a plurality of particular radially to the axis of rotation (A) staggered substrate receptacles for fixing substrates ( 7) exhibiting susceptor (4), with a stationary to the reactor housing (1) radially offset from the axis of rotation (A) on the susceptor (4) arranged measuring point (13), with an optical emission value measuring device (10) and an optical reflection value measuring device (11), which are set to different times (ti, ti + i ) at the measuring point (13) emissivity values (Ei) and reflectivity values (Ri, Ri + i ) on the rotating susceptor (4) measure, and with an evaluation device (15), which from the reflectivity values (Ri, Ri + i ) and the emissivity values (Ei) temperature values (Ti) calculated, characterized in that the evaluation device (15) is arranged so that s for calculating a temperature value (Ti) at least two reflectivity values (Ri, Ri + i ) are used.
11. Verfahren oder Vorrichtung nach einem der vorhergehenden Ansprüche oder CVD-Reaktor nach Anspruch 10, dadurch gekennzeichnet, dass aus genau einem Emissivitäts wert (Ei) unter Verwendung mehrerer Reflekti- vitätswerte (Ri, Ri+i) genau ein Temperaturwert berechnet wird. 11. A method or apparatus according to any one of the preceding claims or CVD reactor according to claim 10, characterized in that exactly one temperature value is calculated from exactly one emissivity value (Ei) using a plurality of reflectivity values (Ri, Ri + i ).
12. Messeinrichtung zum Messen einer Oberflächentemperatur aufweisend eine Emissionswert-Messeinrichtung (10) zur Messung der Emissivität der Oberfläche an einer Messstelle (13), eine Reflektionswert-Messeinrichtung (11) zur Messung eines Reflektivitätswertes der Oberfläche an der Mess- stelle (13) und eine Auswerteeinrichtung (15), dadurch gekennzeichnet, dass die Auswerteeinrichtung (15) so eingerichtet ist, dass zur Berechnung eines Temper aturwertes (Ti) mindestens zwei Reflektivitäts werte (Ri, Ri+i) verwendet werden. 12. A measuring device for measuring a surface temperature comprising an emission value measuring device for measuring the emissivity of the surface at a measuring point, a reflection value measuring device for measuring a reflectivity value of the surface at the measuring point an evaluation device (15), characterized in that the evaluation device (15) is set up so that for the calculation a temperature value (Ti) at least two reflectivity values (Ri, Ri + i ) are used.
13. Verfahren, Vorrichtung, CVD-Reaktor oder Messeinrichtung, gekenn- zeichnet durch eines oder mehrere der kennzeichnenden Merkmale eines der vorhergehenden Ansprüche. 13. Method, device, CVD reactor or measuring device, characterized by one or more of the characterizing features of one of the preceding claims.
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