WO2016083373A1

WO2016083373A1 - Method for calibrating a pyrometer arrangement of a cvd or pvd reactor

Info

Publication number: WO2016083373A1
Application number: PCT/EP2015/077502
Authority: WO
Inventors: Ben Russell VAN WELL; Paul Janis Timans
Original assignee: Aixtron Se
Priority date: 2014-11-27
Filing date: 2015-11-24
Publication date: 2016-06-02
Also published as: TWI680281B; TW201625910A; DE102014117388A1; CN107110709A; CN107110709B

Abstract

The invention relates to a method for calibrating a pyrometer arrangement for measuring the surface temperature of a substrate resting on a susceptor of a CVD or PVD reactor. Said pyrometer arrangement comprises a first pyrometer which is precalibrated in a factory or in a precalibrating step, which is sensitive in a narrow spectral range having a width of less than 20nm, and at least one second pyrometer which is sensitive in a second, wide spectral range having a width of more than 100nm. According to said method, in a first step, the first pyrometer is calibrated and in a second step, the susceptor or a calibrating element is tempered to a calibration temperature or subsequently to several calibrating temperatures (T1, T2, T3, T4) which are different from each other, which is measured by the first pyrometer and is used as a reference point (S1, S2, S3, S4) for determining a characteristic curve of the second pyrometer.

Description

Method for calibrating a pyrometer arrangement of a CVD or PVD reactor

A device for depositing semiconductor layers, for example in III-IV semiconductor layers, has a reactor housing, a susceptor arranged therein, for example of graphite or coated graphite, a heating device arranged below the susceptor, for example an IR, RF or A lamp heating device, a gas inlet member, which is arranged above the susceptor, and with which process gases are introduced into the process chamber, and one or more temperature-sensitive sensors, to determine the surface temperature of the substrates resting on the susceptor and supply them to a control device, with the the heater can be controlled so that the surface temperature is maintained at a predetermined value. Such a device describes, for example, DE 10 2012 101 717 AI. In conjunction with a plurality of sensors and a multi-zone heating, the control device can regulate the temperature distribution on the susceptor and thus on the substrates and from substrate to substrate.

DE 10 2004 007 984 A1 describes a CVD reactor with a process chamber arranged in a reactor housing. The bottom of the process chamber is formed by a susceptor which carries the substrates to be treated, in particular to be coated. The process chamber ceiling is formed by a gas inlet member having inlet openings through which the process gases can enter the process chamber. Below the susceptor, a heater is arranged to heat the susceptor to the treatment temperature. The surface temperature of the susceptor is measured by means of a plurality of temperature measuring sensors. Moreover, the prior art also includes US Pat. No. 6,492,625 B1, EP 1 481 117 Bl, DE 10 2007 023 970 A1. The temperature measurement of the surfaces of the substrates is usually carried out with a pyrometer. The pyrometer must be calibrated before using it as a temperature measuring device. EP 2 251 658 B1 and EP 2 365 307 Bl describe a method for calibrating a pyrometer using a light source which simulates a "Planck" emitter. It is a light source which the pyrometer uses during calibration with a regulated light source Irradiated reference radiation flux, which is equivalent to a black body radiation in a relatively limited spectral wavelength range and corresponds to a previously calibrated reference temperature in the pyrometer.

Such a device with multiple light sources describes a

US 2013/0294476 AI.

The aforementioned documents each describe methods for calibrating a narrow-band pyrometer. Such pyrometers are, for example, sensitive to a wavelength of 950 nm, the bandwidth being <10 nm. The intensity measured with a narrow-band pyrometer of this type depends on the temperature T as follows: I = A * exp (- B / T), where A and B are constants to be determined in the calibration method. It is essentially important to determine the parameter A, which depends on the quality of the light path from the measuring point to the sensor, ie in particular on the permeability of a window or the size of a critical aperture. Parameter B is typically set during manufacture when the pyrometer is being baseline calibrated. This is done using a black body radiator. The parameter B is determined in particular by a narrow-band pyrometer by the wavelength at which the pyrometer is sensitive, and is often determined by the choice of Filters, which determines the wavelength and wavelength bandwidth in the sensor, set.

The prior art also includes the following writings pertaining to the calibra- tion of pyrometers: US Pat. No. 6,398,406, EP 0 490 290 B1, US Pat.

US 6,151,446, US 8,296,091, US 6,963,816, WO 2004/00184, US 6,379,038,

WO 0054017, US 2002/066859, WO 99/13304, WO 98/04892, EP 0 801 292,

WO 97/11340, WO 98/53286, US 5,249,142, US 4,979,134, US 4,979,133,

EP 0 317 653, US 4,708,474 and US 4,222,663.

The temperature measurement of a substrate surface with a narrow-band pyrometer, as is common in the prior art, has the disadvantage that a reliable control of the heating is not possible. The temperature measurement value is influenced, for example, during layer growth by the Fabry-Perot effect. Because of the low intensity, the measured values of a narrow-band pyrometer suffer from a large signal noise. To avoid sensor drift due to changing sensor temperatures, filters are used in narrowband pyrometers. Also, occupying the window through which the optical path passes affects the measurement result.

In addition to narrow band pyrometers (bandwidth <20 nm, preferably <10 nm), broadband pyrometers are used (bandwidth> 100 nm, preferably> 200 nm). Due to their larger bandwidth, these pyrometers receive a much stronger light signal from the surface to be measured. They are less sensitive to temperature drift. For larger bandwidth pyrometers, the temperature reading is less sensitive to thin film interference effects (Fabry-Perot effect) and less sensitive to wavelength aberrations. pendent scattering on structured substrates. However, there is a significant temperature drift due to missing filters.

The method described above for the calibration of narrow-band pyrometers is no longer possible with broadband pyrometers for a number of reasons. On the one hand, the reference radiation sources with defined radiation flux described above, which corresponds to a calibrated radiation temperature, and which has the spectral characteristic of a black body radiator, are virtually unavailable for larger bandwidths (eg> 10 nm). On the other hand, the relation I = A * exp (- B / T) over larger spectral ranges is not true because the sensitivity of the photodetectors used is wavelength-dependent. The relation for the spectral radiation intensity, the Planck equation is:, where the constant Cl is wave-length

may be gene dependent, if the detector sensitivity is wavelength dependent. As a result, the relation I = A * exp (- B / T) no longer applies over the entire spectral range, but runs non-linearly in the plot log (I) over 1 / T. Due to this non-linearity, it is no longer possible to represent the relation between signal intensity in the detector and temperature of the measurement object by means of two calibration constants A and B. Therefore, it is often customary to use blackbody radiation sources for the calibration of broadband pyrometers. These are cavity radiant heaters heated to the respective radiant temperature. These are common for initial factory calibration of the pyrometers, but too bulky for calibration or sporadic recalibration of pyrometers on the system and too time consuming due to long temperature stabilization times.

Numerous methods are known for describing or approximating the relation for the measuring method with sufficient precision, for example by increasing a fit function. Order of the log in (1) over 1 / T plot non-linear curve or by piecewise linearization, so that the relation I = A * exp (- B / T) for certain temperature sections 1,2,3, ... exists , with calibration parameters AI, A2, A3,..., Bl, B2, B3,..., or a combination of both, that is, piecewise approximations of a higher order. The starting point is in each case the availability of sufficiently many support points along the log (I) via 1 / T plot of the pyrometer.

The amount of light reaching the pyrometer can depend on further geometric effects, for example on the occupation of a window. If the window occupancy affects the transmissivity of the window differently for mutually different wavelengths, several pyrometers sensitive to each other from different wavelengths can be used. To determine the surface temperature then not only the absolute intensity value, but also a ratio between the two intensity values is used.

The amount of light reaching the pyrometer can depend on geometric effects, but also on the unknown emissivity of the hot object to be measured, in particular of the substrate coated in the process. Unknown or erroneously known emissivity leads to errors in the temperature determination by pyrometers, in which the radiation quantity arriving at the sensor is set in relation to the temperature of the radiation-emitting object via the Planck's radiation equation. To address this problem, the following known technical solutions exist: a) determination of the emissivity during the temperature measurement process by measuring the reflection of a light signal at the same wavelength at which the detector of the pyrometer is sensitive b) use of two or more different from each other Wavelength sensitive detectors in the pyrometer array and determining the surface temperature of the object by the ratio of the two or more intensities. tätswerte, as a so-called quotient pyrometer. The technical solution a) has several disadvantages, for example scattering of the reflection signal on structured substrates or on the surface of a rough susceptor instead of the substrate surface leads to an underestimation of the reflectivity and overestimation of the emissivity (E = 1-R), with partially transparent substrates , such as sapphire, E = 1-R is no longer valid, and the spectral distribution of the reflection signal must match the spectral distribution of the sensitivity of the detector, in practice this is only for relatively narrow bandwidths (<50 nm, often only <20) nm), the above-mentioned advantages of broadband measurement are then incompatible with this type of emissivity correction. The technical solution b) circumvents these limitations of the solution a) by no reflection measurement is required and thus by the use of broadband detection of the radiation emitted by the measuring object (substrate, susceptor) radiation is possible in a simple manner. With the solution b), ie broadband ratio pyrometer, the insensitivity to thin-film interference effects (Fabry-Perot effect) can be combined with the use on rough surfaces or structured substrates and combined with the use at low signal intensities, so that the signal-to-noise ratio. Noise ratio is superior to narrowband detectors. A limiting prerequisite for accurate temperature determination by forming the ratio of the intensities at the mutually different wavelengths is that the emissivity of the measurement object is approximately constant at the two wavelengths, within the range of the temperature measurement accuracy to be achieved. The emissivity then cuts out in the quotient formation. Sapphire and GaN as well as the susceptor graphite meet this requirement relatively well in the wavelength range relevant for the measurement (again within the scope of the accuracy of the method to be achieved). Strong wavelength-dependent influences on the emissivity, such as the Fabry-Perot effects, are sufficiently attenuated by the broadbandness of the detection. Another advantage of using quotient pyrometers is that geometric changes along the optical path, or changes in the optical path Transmission as by turbidity or occupancy of optical windows along the beam path in a manner analogous to the emissivity of the test object in the quotient formation, provided that these changes to the intensity at the location of the detector evenly for the mutually different wavelengths, with broadband detectors evenly over the affect the entire relevant spectral range.

However, certain technical problems arise in solution b): The occupancy or turbidity of an optical window in the optical path from measurement object to detector can change the transmission of the radiation in a wavelength-dependent manner. As a result, the temperature measurement result is erroneous, there is a drift in the determined temperature compared to the actual temperature of the measurement object. In the case of long-term use of the pyrometer arrangement, for example in semiconductor manufacturing, this requires recalibration of the detectors, for example as part of the usual maintenance cycles. One known method of calibration relies on the use of blackbody radiation over the entire relevant spectral range produced by cavity-cavity ovens. However, these ovens are virtually unsuitable for recalibration of pyrometers installed on the process chamber or in the process chamber due to their size and long temperature stabilization times.

This results in the total for the use of broadband pyrometers for temperature measurement in the described application in semiconductor processing the task of finding a calibration method that does not have the disadvantages of the known calibration and the restriction to sufficiently narrowband pyrometer. The invention has for its object to provide a method for calibrating a broadband pyrometer.

The object is achieved by the invention specified in the claims.

To enable the described calibration, use is made of a pyrometer arrangement consisting of a first narrow-band pyrometer sensitive in a certain spectral range and of at least one second broadband pyrometer having a spectral range different from the first pyrometer and larger as that of the first pyrometer. Both pyrometers are preferably directed to the same location. They may have the same optical path, but may alternatively have different optical paths. Alternatively, for a rotating susceptor, both pyrometers may also be at the same radius at different locations. The second pyrometer can also consist of a quotient pyrometer in which two or more broadband pyrometers or detectors are used to determine the temperature from the intensity ratio. The actual temperature measurement is carried out with the broadband pyrometer, the narrowband pyrometer has an auxiliary function for the calibration of the one or more broadband pyrometer. During temperature measurement during production on the system, the narrow-band pyrometer for temperature control is not used at all.

The inventive calibration method, for example, essentially begins with the following preparatory steps: Providing a pyrometer array whose pyrometers have individually undergone a factory calibration by a black body furnace, so that by the steps described below, an adaptation to the actual geometric conditions in the process chamber during assembly or to a Fehlkalibrierung by long-term operation, window opacity, aging of the detectors or electronics ,

Providing a CVD or PVD reactor having a susceptor for receiving a substrate,

Providing a first pyrometer, which is sensitive to a first wavelength in a first spectral range, in particular narrowband,

Providing a second pyrometer, which is sensitive in a second spectral range, in particular broadband at a second wavelength.

First, in a first step, the first pyrometer is calibrated. This is done with the calibration tools described in the aforementioned literature, that is, for example, with a reference body which is heated to different temperatures. Since the first pyrometer is a narrow-band pyrometer, an elevated temperature is generally sufficient to determine the position of the line in a plot log (I) over 1 / T, rectilinear characteristic. However, the calibration can also be carried out with a calibration tool, which is essentially a light source, which simulates the light emission of a heated reference body in a certain, in practice relatively narrow, wavelength range, and wherein the radiation power of the light emission is assigned by factory calibration a fixed temperature. In a subsequent step, the susceptor or, instead of a substrate, a calibration body resting on the susceptor is brought to one or more different calibration temperatures. This is done in particular by Heating the susceptor, which may be a calibration, or a resting on the susceptor calibration. The calibration temperatures are measured with the already calibrated first pyrometer. The measured values resulting from the measurement of the temperatures by the already calibrated narrow-band pyrometer are used as reference points of a characteristic curve of the second pyrometer. By the characteristic of a pyrometer is meant the assignment of temperatures to signal intensities, it is often plotted in the form log (I) over 1 / T. From the characteristic calibration parameters for the associated pyrometer can be determined, which are stored on the control unit of the pyrometer, and measurements in the subsequent use on targets of unknown temperature and / or unknown emissivity for the assignment of to be determined measuring temperature to the corresponding measured signal intensity due to the Pyrometer incoming spectral radiant power. The measured values can also be used to determine the calibration parameters for the broadband pyrometers for a section-wise linear approximation or section-wise approximation of a higher order or for a higher-order approximation over the entire temperature range. The characteristic of the second broadband pyrometer is generally not a straight line in the Arrhenius plot, but a curve whose course depends on the diversity of the sensitivity spectrum of the sensor from the emission spectrum of the reference body. It is envisaged that both pyrometers measure the intensity of the light emitted by the same measuring point (infrared light). The optical path from the measuring point to the pyrometers preferably passes through a gas outlet opening of the gas inlet member and through a window arranged on the rear side of the gas inlet member. The pyrometer assembly may be located within the reactor housing. However, it can also be located outside the reactor housing. Then the optical path passes through another window. A steel divider can be provided, with which the optical path is divided into at least two partial paths, each partial path leading to one of the two pyrometers. The narrowband pyrometer can work on one Wavelength of 950 nm sensitive. The bandwidth is preferably below 50 nm, preferably in the range of 20 nm, 10 nm or below. The broadband pyrometer can be sensitive to the same wavelength. The bandwidth is preferably greater than 100 nm. It may be greater than 200 nm. While a measuring point is generally sufficient for calibrating the narrow-band pyrometer, at least three measuring points are preferably determined for calibrating the broadband pyrometer in a temperature range between 200 and 1,300 ° C. This results in two temperature ranges, the basic characteristic curve consisting of two interpolation points define. The basic characteristic can be formed in a representation log (I) over 1 / T of two straight lines or a smooth curve laid down by the support points. Preferably, more than three support points are recorded at more than three different temperatures. As a calibration body, a ceramic body can be used. It is intended in particular to use a graphite body, a SiC-coated graphite body, a silicon substrate, a SiC body or a substrate coated with S1O2 or S13N4 as the calibration body. The calibration body can be an optically gray body. The emissivity of the calibration body must be known for the assignment of temperature and signal intensity. If it is a calibration body with non-constant emissivity (ie non-gray body), 20 then the dependence of the emissivity of temperature and wavelength must be known. In a further development of the invention, the pyrometer arrangement has a third broadband pyrometer, which has substantially the same task as the second broadband pyrometer, namely in regular operation of the CVD / PVD device, the surface temperature of the susceptor or a substrate at a certain point to eat. The two broadband pyrometers are sensitive to spectral regions which are different from one another, for example, the broadband pyrometer can be formed by a Si PIN diode. This pyrometer is sensitive in a spectral range from 400 to 1200 nm. The second broadband pyrometer may be an InGaAs detector. This pyro meter is sensitive in a range between 1,100 and 1,700 nm. The temperature Determination of the temperature in regular operation of the PVD / resp. CVD setup is performed using the measurements of both broadband pyrometers, using not only the absolute measurement, but also the ratio, that is, the quotient of the two measurements. The calibration of the third pyrometer, ie the second broadband pyrometer, is analogous to the calibration of the first broadband pyrometer, ie in the second calibration step. The calibration of the two broadband pyrometer takes place at the same time at the same calibration temperatures and using the same calibration element, which may be a calibration or a special susceptor. The narrow-band pyrometer is sensitive to a first wavelength λι. The second pyrometer is sensitive to a second wavelength λ ₂ . The third pyrometer is sensitive to a wavelength λ ₃ . The first wavelength λι, the second wavelength λ ₂ and the third wavelength λ ₃ may be within a frequency band corresponding to the bandwidth of one of the broadband pyrometer. The wavelengths λι, λ ₂ , λ ₃ may be the same wavelengths, but they may also be different from each other. The bandwidth of the two broadband pyrometers can be different. But you can also be the same. They can be offset by a certain amount, with the bandwidths overlapping or not overlapping. The broadband pyrometer is preferably a quotient pyrometer having a silicon detector that is substantially sensitive in a spectral range between 450 nm and 1000 nm, and an InGaAs detector that is substantially sensitive in a special range between 1,000 and 1,700 nm is. The measured value supplied by this pyrometer is the quotient of the measured values of the two detectors. The first pyrometer is a broadband pyrometer by design. However, it is preceded by a narrowband filter, so that it receives only light in the wavelength range specified by the filter. The calibration element used is a body in which the temperature profile of the emissivity is known. Embodiments of the invention are explained below with reference to accompanying drawings. Show it:

1 is a schematic sectional view of the essential details of a process chamber of a CVD reactor with a pyrometer arrangement 10, 11, 12, 12 'of a first embodiment,

2 shows the illustration according to FIG. 1 during the calibration of the narrowband first pyrometer 11, FIG.

3 shows a representation according to FIG. 1 during calibration of the two broadband pyrometers 12, 12 ',

4 shows a representation according to FIG. 1 of a second exemplary embodiment,

Fig. 5 is a graph log (I) on 1 / T of a characteristic of a narrow-band pyrometer 11, and

Fig. 6 is a plot log (I) on 1 / T of a characteristic of a broadband pyrometer, which is determined by four at temperatures Ti, T ₂ , T ₃ , T ₄ measured support points Si, S ₂ , S ₃ , S _{4 is} drawn.

FIG. 1 or FIG. 4 show the interior of a CVD reactor 1. The reactor housing is not shown. Within the reactor housing is a shower-head-like gas inlet member 2 with a gas outlet surface which has a multiplicity of gas outlet openings 3, 3 'distributed uniformly over the circular disk-shaped surface. Below the gas outlet surface of the gas inlet member 2 is located a process chamber 8, whose bottom is formed by a susceptor 6 of coated graphite. On the side facing the process chamber 8 top of the susceptor 6 are to be coated substrates 9. In FIG. 1, for the sake of clarity, only one substrate 9 is shown. Below the susceptor 6 is a heater 7. It can be an infrared heater.

The rear side of the inlet member, that is, the side facing away from the gas outlet surface has a window 5, 5 '. The window 5, 5 'is located above a gas outlet opening 3. An optical path 13 emanating from a measuring point 15 on the substrate 9 is split into a beam splitter 14 into two optical paths 13', 13 "via the optical path 13, 13 ' a first pyrometer 11 light emitted by the measuring point 15 according to Planck 's law of radiation .A second pyrometer 12 receives from the measuring point 15 the temperature radiation in the infrared range via the optical path 13, 13 ".

An electronic control device 10 is provided, which cooperates with the two pyrometers 11 and 12 and is able to control the heating device 7.

The first pyrometer 11 is a narrow-band pyrometer, which is sensitive to a wavelength of 950 +/- 5 nm. It may be a silicon photodiode, which is preceded by a narrow band filter 18, which passes only the said wavelength of 950 nm.

The second pyrometer 12 has a silicon photodiode. This Si photodiode is not preceded by a bandpass filter. The second pyrometer 12 is part of a pyrometer arrangement consisting of two pyrometers 12, 12 '. It is from a Silicon photodiode formed. It is a broadband pyrometer, which is operated on the entire spectral range of a silicon photodiode. This pyrometer assembly may include a third pyrometer 12 'which is formed by an InGaAs diode. This broadband pyrometer 12 'is sensitive to a correspondingly wide spectral range of an InGaAs diode. The narrowband pyrometer 11 and the two broadband pyrometers 12, 12 'receive infrared light from the same measuring point 15 through the same gas outlet 3 and the same window 5. Instead of two gangrenous pyrometers 12, 12', it is also possible to use only a broadband pyrometer 12 - the.

In the embodiment shown in FIG. 4, two pyrometer arrangements are provided, which have a same structure. The two broadband pyrometers 12, 12 'are separated from one another and receive their associated light in each case via a steel divider 14'. The two sensor arrangements measure the light emission at two different locations on the surface of the susceptor 6. The two locations 15, 15 'differ substantially by their radial distance Rl, R2 from a center axis A. The susceptor 6 can be rotated about this center axis A. , Temperatures at different radial distances can thus be measured with the sensor arrangements.

During operation of the CVD reactor, in which process gases are introduced through a feed line 4 into the process chamber 2, 3 enter through the Gasaustrittsöffnun- 3, 3 'in the process chamber 8 and there pyrolytically disassemble on the surface of the substrate 9 layer forming, is with the second pyrometer 12, 12 ', the temperature at the measuring point 15, 15' measured. This temperature is supplied to the control device 10, which is able to apply the heater 7 in such a way. control that the temperature measured at the measuring point 15 is kept at a constant value.

When using pyrometer arrangements with in each case two broadband pyrometers 12, 12 ', not only the absolute values of the two broadband pyrometers 12, 12' are evaluated for temperature regulation or for determining a temperature measurement value. In addition, a quotient of the two absolute measured values is formed and this quotient is evaluated. By means of this measured value evaluation, it is possible to take into account assignments of windows through which the light emitted by the measuring point passes.

In a variant, not shown, further pyrometer arrangements 11, 12, 12 'are provided, each receiving infrared light passing through mutually different gas outlet openings 3' in order to determine the temperature on the susceptor surface at different measuring points. The pyrometer arrangements are arranged at further radial positions.

The calibration of the broadband pyrometer 12 or the two broadband pyrometers 12, 12 'takes place in the following steps:

First, a calibration tool 16 is used, as described in the aforementioned EP 2 365 307 Bl and EP 2 251 658 Bl. This, a temperature-radiating gray or black body simulating tool 16 is located below the gas outlet opening 3. The light emitted by the calibration tool 16 hits the sensor surface of the narrow-band pyrometer. It may be a Si PIN diode with an optical filter defining the spectral range. The narrow-band pyrometer 11 is factory in such a way precalibrated that the slope of the characteristic need not be changed in a representation log (I) over 1 / T. By calibration, essentially only the vertical position of the characteristic curve is determined. With the calibration tool 16, the characteristic shown in Figure 4 and in particular their altitude (characterized by the double arrow and the dashed parallel lines) determined.

Alternatively, however, a calibration element within the process chamber can be heated to a predetermined temperature. The first, narrowband pyrometer 11 is then calibrated with the light of this heated calibration element.

Subsequently, the calibration tool 16 or a calibration element is removed from the process chamber. In the process chamber 8, a calibration body 17 is used. The calibration body may be a silicon or sapphire substrate or a coated silicon substrate or a coated sapphire substrate. However, it may also be a silicon substrate or a sapphire substrate which is provided with GaN or another III-V layer. It may be the same body used as a calibration element in calibrating the first pyrometer. It may be a ceramic plate, a graphite plate or a metal plate. By means of the heater 7, the susceptor 6 is first heated to a calibration temperature of> 200 ° C. If the surface temperature on the calibrating body 17 has stabilized, a first temperature Ti is measured with the already calibrated narrowband pyrometer 11. The at this temperature Ti from the second

Pyrometer 12 measured intensity is plotted as a supporting point Si in the diagram (Figure 5). Likewise, at the same temperature Ti, the third pyrometer 12 'is also calibrated. The temperature is then increased, for example, to 400 °. This temperature T ₂ is measured with the first pyrometer 11. The intensity measured at this temperature T ₂ with the second pyrometer 12 is entered as a support point S ₂ in the diagram according to FIG. Corresponding measurements are measured at higher temperatures, for example at a temperature T ₃ of 800 ° C. and a temperature T ₄ 1200 ° C. The associated intensities are entered as support points S ₃ and S ₄ in the diagram shown in FIG. In the same way, the third pyrometer 12 'can be calibrated.

Subsequently, a characteristic curve is created for each of the second pyrometer 12 and / or the third pyrometer 12 '. For this purpose, a polygonal line (dashed line in FIG. 5) is drawn through the support points or a smooth spline is laid.

The result is a basic characteristic with which the broadband pyrometer 12 or 12 'is able to determine the temperature of a substrate with the optical properties of the calibration body. From the basic characteristic, other characteristics can be derived for substrates having another known optical property.

The above explanations serve to explain the inventions as a whole, which further develop the state of the art independently, at least by the following feature combinations, namely:

A method, characterized in that in the first step, the first pyrometer 11 is calibrated and in a second step of the Susceptor 6 or a calibration element 17 to a calibration temperature or successively to a plurality of mutually different calibration temperatures Ti, T _{2 /} T ₃ , T _{4 is} tempered, which is measured with the first pyrometer 11 and as a support point Si, S _{2 /} S _{3 /} S _4th is used to determine a characteristic of the second pyrometer 12.

A method which is characterized in that the bandwidth of the first pyrometer 11 is smaller than 10 nm and the bandwidth of the second pyrometer broadband, in particular with a bandwidth greater than 100 nm, preferably greater than 200 nm.

A method, characterized by a third, in a third broadband spectral sensitive pyrometer 12 ', which is calibrated together with the second pyrometer 12 in the second step and which forms a second Pyrometer 12 a quotient pyrometer with different spectral ranges.

A method which is characterized in that the first pyrometer 11 is calibrated with a susceptor 6 or calibration element 17 arranged inside the CVD or PVD reactor.

A method which is characterized in that the calibration of the first pyrometer 11 takes place by means of a light-emitting calibration tool 16 with a known temperature dependence of the emissivity, for example of a temperature-controlled reference body or of a light source. A method which is characterized in that the two or three pyrometers 11, 12, 12 'in the calibration evaluate the intensity of the light emitted by the same measuring point 15 light.

A method in which the two pyrometers 11, 12, light, which is emitted from the same place, receive and in particular and at least over a partial route using the same optical path.

A method which is characterized in that the optical path 13 from the measuring point 15 to the first pyrometer 11 and the second pyrometer 12 or third pyrometer 12 'through a arranged on the front side of the Gasauslassorganes 2 gas outlet opening 3 of a gas inlet member 2 and through a window 5 on the back of the gas inlet member 2 passes.

A method which is characterized in that three or more support points Si, S ₂ , S _{4 are determined} at a different temperature Ti, T ₂ , T ₃ , T ₄ , in particular in a temperature range between 200 and 1300 ° C.

A method, characterized in that the reference body or the calibration element 17 is a susceptor used only for the calibration is a plate made of a ceramic material, graphite or a semiconductor material, which is arranged on the susceptor 6 instead of a substrate.

A method which is characterized in that, when the susceptor 6 or the calibration element 17 is tempered, second or third pyrometers 12, 12 'are provided. terer Pyrometeranordnungen be calibrated, each evaluating the intensity of the light emitted from different measuring points light.

A method characterized in that the calibration element 17 is made of a material belonging to the following group of materials: SiC, SiC coated Si, graphite, SiC coated graphite, Si, Si with a coating of SiO ₂ or S13N4 ,

All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure 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 the present application. The subclaims characterize with their features independent inventive developments of the prior art, in particular to make on the basis of these claims divisional applications.

LIST OF REFERENCE NUMBERS

1 CVD reactor

2 process chamber

3 gas outlet

4 supply line

5 windows

5 'window

6 susceptor

7 heating

8 process chamber

9 substrate

10 control device / pyrometer arrangement

11 pyrometer / arrangement

12 Pyrometer / Array A Center Axis 12 'Pyrometer / Array

13 Optical path / path

13 'Optical path / path

13 "optical path / path

14 beam splitter

14 'beam splitter

15 measuring point

16 calibration tool

17 Calibration element

18 narrowband filters

Claims

A method of calibrating a pyrometer array (11, 12) for measuring the surface temperature of a substrate (9) resting on a susceptor (6) of a CVD or PVD reactor (1), the pyrometer array having a first, in a narrow spectral range with a bandwidth smaller than 20 nm sensitive, pre-calibrated at the factory or in a Vorkalibrierschritt pyrometer (11) and at least a second, in a second broadband spectral range with a bandwidth greater than 100 nm sensitive pyrometer (12, 12 ') at in a first step the first pyrometer (11) is calibrated and in a second step the susceptor (6) or a calibration element (17) to a calibration temperature or successively to a plurality of mutually different calibration temperatures (Ti, T ₂ , T ₃ , T ₄ ), which is measured in each case with the first pyrometer (11) and as a support point (Si, S ₂ , S ₃ , S ₄ ) for determining a characteristic of the second n pyrometer (12) is used.

2. The method according to claim 1, characterized in that the bandwidth of the first pyrometer (11) is less than 10 nm and the bandwidth of the second pyrometer is greater than 200 nm.

3. The method according to any one of the preceding claims, characterized

by a third, in a third broadband spectral range sensitive pyrometer (12 '), which is calibrated together with the second pyrometer (12) in the second step and which forms with the second pyrometer (12) a quotient pyrometer with different spectral ranges.

4. The method according to any one of the preceding claims, characterized in that the first pyrometer (11) with the one of the inside of the CVD or PVD reactor arranged susceptor (6) or calibration element (17) emitted temperature radiation is calibrated.

5. The method according to any one of the preceding claims, characterized in that the calibration of the first pyrometer (11) by means of a light-emitting Kalibrierwerkzeugs (16) with a known temperature dependence of the emissivity, eg. A tempered reference body or a light source.

6. The method according to any one of the preceding claims, characterized in that the two or three pyrometers (11, 12, 12 ') in the calibration evaluate the intensity of the light emitted from the same measuring point (15).

7. The method according to any one of the preceding claims, characterized in that the first pyrometer (11) and the second pyrometer (12) are directed to the same measuring location and at least over a partial route have the same optical path.

8. The method according to any one of the preceding claims, characterized in that the optical path (13) from the measuring point (15) to the first pyrometer (11) and the second pyrometer (12) or third pyrometer (12 ') by a on the front side of Gas outlet organ (2) arranged

Gas outlet opening (3) of a gas inlet member (2) and through a window (5) on the back of the gas inlet member (2) passes.

9. The method according to any one of the preceding claims, characterized in that three or more support points (Si, S ₂ , S ₄ ) in each case one another Temperature (Ti, T _{2 /} T 3, T ₄ ) are determined, in particular in a temperature range between 200 and 1300 ° C.

Method according to one of the preceding claims 4 to 9, characterized in that the reference body or the calibration element (17) is a susceptor used only for the calibration of a ceramic material, graphite or a semiconductor material consisting of plate instead of a substrate on the Susceptor (6) is arranged.

11. The method according to any one of the preceding claims 4 to 10, characterized in that during the temperature control of the susceptor (6) or the calibration (17) second or third pyrometer (12, 12 ') further pyrometer assemblies are calibrated, each of the intensity of Evaluate emitted light from different measuring points.

12. The method according to any one of the preceding claims 4 to 11, characterized in that the calibration element (17) consists of a material belonging to the following group of materials: SiC, SiC coated Si, graphite, SiC coated graphite, Si, Si with a coating of Si0 ₂ or Si ₃ N ₄ .

13. Method, characterized by one or more of the characterizing features of one of the preceding claims.