WO2004059271A1 - Verfahren zum bestimmen der temperatur eines halbleiterwafers in einer schnelheizanlage - Google Patents
Verfahren zum bestimmen der temperatur eines halbleiterwafers in einer schnelheizanlage Download PDFInfo
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- WO2004059271A1 WO2004059271A1 PCT/EP2003/013387 EP0313387W WO2004059271A1 WO 2004059271 A1 WO2004059271 A1 WO 2004059271A1 EP 0313387 W EP0313387 W EP 0313387W WO 2004059271 A1 WO2004059271 A1 WO 2004059271A1
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Classifications
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- 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
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/324—Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering
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- 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
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- 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
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- 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
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67098—Apparatus for thermal treatment
- H01L21/67115—Apparatus for thermal treatment mainly by radiation
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- 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
Definitions
- the present invention relates to a method for determining at least one state variable from a model of an RTP system by means of at least one measurement signal tapped from the RTP system, the measured variable, which has a dependency on the state variable to be determined.
- the present invention relates to a method for determining the temperature of an object, preferably a substrate, such as e.g. a semiconductor wafer in a rapid heating system in which the object or the substrate is heated with radiation sources.
- Rapid heating systems for the thermal treatment of substrates such as Semiconductor wafers are widely known in semiconductor manufacturing. They are used for the thermal treatment of wafers, which are preferably made of silicon, but which also consist of compound semiconductors such as II-VI, III-V and IV-IV semiconductors can exist.
- An important feature in the thermal treatment of the semiconductor wafers in a rapid heating system is precise control or regulation of the wafer temperature during the thermal treatment. This control or regulation of the wafer temperature in turn requires a precise determination of the wafer temperature during the thermal treatment in order to control or regulate the rapid heating system accordingly.
- the present invention relates specifically to the aspect of determining the temperature of a semiconductor wafer during its thermal treatment in a rapid heating system. In general, the invention relates to the determination of a state variable from a model of an RTP system, which describes the state of the RTP system by means of model parameters.
- thermocouples Semiconductor wafers in a rapid heating system are known.
- thermocouples there is the problem that the thermocouples on the one hand require complex attachment to the semiconductor wafers and on the other hand lead to local temperature inhomogeneities, since they generally have to be in thermally conductive contact with the semiconductor wafers and furthermore the radiation field in the rapid heating system at least in the vicinity of the thermocouple influence.
- Another contactless method which is known, for example, from the applicant's patent applications and patents DE-A-19852320, US 6,191, 392 and US 6,396,363, uses a contactless temperature measurement.
- a first pyrometer is provided, which is directed towards one side of the wafer in order to detect radiation coming from the wafer, which contains both heat radiation from the wafer and radiation from the radiation sources reflected on the wafer.
- a second pyrometer is provided which is directed towards the radiation sources themselves in order to detect radiation emitted by the radiation sources and which is provided with a modulation.
- the modulation of the radiation sources is chosen such that it is not reflected in the thermal radiation of the wafer, but can be measured in the radiation of the radiation sources reflected on the wafer.
- the thermal radiation of the wafer measured on the first pyrometer can be separated to a certain degree from the radiation of the radiation source reflected on the wafer. The temperature of the wafer can then be determined from the heat radiation.
- this type of temperature determination requires two pyrometers or detectors, namely a so-called wafer pyrometer (or generally a detector for measuring the radiation emitted by the wafer and reflected on the wafer or transmitted through the wafer) and a lamp pyrometer (or a second measuring system for detection the radiation emitted by the lamps or radiation sources), each of which is associated with high costs.
- the lamp pyrometer or the second measuring system not only detects radiation originating from the radiation sources, but also partly radiation originating from the wafer, which complicates accurate temperature determination of the semiconductor wafer and requires additional means for the precise determination of the lamp radiation, as is described in the patent application DE-A-19852321, which goes back to the applicant.
- the contactless temperature determination described above with the aid of modulated radiation sources is therefore preferably suitable for quasi-stationary systems, ie for systems or temperature-time processes to which the rapid heating system-wafer system is subjected, which are quasi-stationary, ie in comparison to the modulation frequency of the Radiation sources change only slowly over time.
- a further problem arises from the sensor sensitivity or from the requirements with regard to measurement accuracy, since the contributions of the modulated radiation can be determined very precisely, since this is used to determine the emissivity and / or transmissivity of the object (the wafer) in situ.
- the present invention has for its object to provide a method for determining the temperature of a semiconductor wafer in a rapid heating system, in which the substrate is heated with a radiation source, which is a simple and inexpensive way of good temperature determination Semiconductor wafers enables. Furthermore, the present invention is based on the object of determining a state variable of an RTP system, in particular the state variable being the temperature of a semiconductor wafer in the rapid heating system.
- the method for determining the temperature of an object (preferably a substrate such as a semiconductor wafer) in a rapid heating system in which the object (e.g. a semiconductor wafer) is heated with radiation sources (e.g. radiant heaters), the detection of a control variable of the radiation sources, the detection of a measurement variable which strongly depends on the state variable of an object to be determined in the rapid heating system, or a has a sufficient dependency on the state variable to be determined, such as the temperature of the object (eg the semiconductor wafer), the determination of a predictive value of this measurement variable of the at least one object via a system model of the rapid heating system including the semiconductor wafer (object), which is acted upon by the control variable of the radiation sources, determining a state correction (also referred to in this application as a controlled variable) for the system model from the difference between the measured variable detected and the predicted value of the measured variable and determining at least one state variable of a state of the semiconductor wafer or a state of the system comprising the semiconductor wafer and rapid heating
- the model state is in very good agreement with the system state.
- the model thus represents the state of the real system, which is why the system state to be determined, e.g. the wafer temperature can be tapped directly from the system model.
- This method enables the determination of at least one state variable of a state vector, which preferably describes the state of the system comprising the semiconductor wafer and the rapid heating system, in a simple and inexpensive manner, the temporal development of the system state and its reaction to the control variable being described by a system model, which preferably comprises several sub-models comprises, on the one hand, at least one control variable of the rapid heating system, such as a control variable of the radiation sources, and on the other hand, at least one specific condition correction.
- rapid heating systems are systems in which the different components with distributed system parameters and system states such as emissivity and temperature are in a complex thermal interaction relationship. The complete description of the real system would therefore require a very large number of system parameters and a precise knowledge of the details of all thermal interactions. For reasons of real-time requirements alone, complete model descriptions are therefore generally not feasible, which is why the system models are preferably models that are reduced to the properties of the thermal system that are essential for the correct representation of the dynamics of the state variables of interest.
- This state correction (the reaction of the difference between the predicted values and the measured values to the state and / or the parameters of the observer is also referred to as a controlled variable or control parameter within this application) adjusts the state of the observer to that of the real system by the controller adjusting the difference minimized between the respective output variables.
- the controlled variable is determined by an algorithm that detects a measured variable of an object in the rapid heating system with a predicted value of the measured variable of the Object compares and aims to minimize the difference between these two values.
- the state variable determined on the basis of the model describes the actual state of the system consisting of the semiconductor wafer (object) and the rapid heating system, and thus also the state of the object (semiconductor wafer), which, in addition to other variables of this state, in particular the temperature of the object or the semiconductor wafer can be determined.
- the dynamic behavior of a system can be described using a state equation, whereby the state vector x is composed of one or more state variables.
- the state vector x (t) develops over time, the development over time generally being described by means of a system of differential equations.
- State variables of this type also describe the state or states of a system model, for example the system model comprising the RTP system and the object (semiconductor wafer, substrate).
- Systems or system models are further characterized by parameters, the system parameters generally not developing over time, or no explicit time dependency can be specified for the system parameters. Nevertheless, the parameters determine the transmission behavior of the system or system model, ie the relationship between input and output variables.
- Parameters are, for example, emissivity, transmissivity and reflectivity of the semiconductor wafer in the system model RTP system semiconductor wafer, while, for example, wafer and radiation source temperature (lamp temperature) are state variables.
- the state of the system consisting of the object and the rapid heating system or of the object is generally described, as described above, by a state vector which contains the state variable.
- the method for determining a state variable from a model of an RTP system by means of at least one measurement signal tapped from the RTP system, the measured variable, which has a dependency on the state variable to be determined comprises a measured variable predicted by the model, the predicted value, measured variable and predictive value each comprise components of a direct and alternating component, and wherein at least the alternating component is determined separately by filters in order to form a first difference between the alternating component of the measured variable and the alternated component of the measured variable predicted by the model, a parameter adaptation of at least one model parameter by returning the first difference to the model with the aim of adapting the model behavior to variable system parameters, form a second difference from the measured variable and the predictive value or from the measured variable adjusted for the alternating component and adjusted igt prediction value, state correction of a state of the model system by returning the second difference in the model with the aim of bringing the state of the model system into agreement with that of the real system and tapping at least one
- the state variable preferably represents the temperature of the semiconductor wafer or another variable from which the temperature of the semiconductor wafer can be derived in a unique manner.
- the particular advantage of the above method according to the invention is that only one sensor, for example a pyrometer, is required to record a measured variable in order then to determine the state of the system from the object (semiconductor wafer) and rapid heating system in such a way that, for example, the state of the object with regard to its temperature and / or any optical properties that are a priori unknown system parameters, such as emissivity, transmissivity and / or Reflectivity.
- the particular advantage of the method according to the invention is that only one sensor, for example a pyrometer, is required to record a measurement variable in order to determine a priori unknown system parameters such as emissivity, transmittance and / or reflectivity of the semiconductor wafer by changing the system model by parameter adjustment (Parmeter adaptation) is brought into the best possible agreement with the controlled system (the real system), and to enable the state correction with which the states of the observer and the controlled system are brought into agreement.
- a priori unknown system parameters such as emissivity, transmittance and / or reflectivity of the semiconductor wafer
- Parameter adaptation Parameter adaptation
- the states of the system model and the controlled system remain consistent even if the optical properties of the semiconductor wafer change (one speaks of variable system parameters, such as the reflectivity, transmissivity and emissivity of the semiconductor wafer, because these parameters are temperature-dependent and thus, at time-dependent temperature of the semiconductor wafer, implicitly time-dependent), as a result of which the temperature derived from a state variable is also close to the real temperature in the controlled system.
- variable system parameters such as the reflectivity, transmissivity and emissivity of the semiconductor wafer, because these parameters are temperature-dependent and thus, at time-dependent temperature of the semiconductor wafer, implicitly time-dependent
- a determination of the lamp or radiation source intensity by means of a further detector, as described, for example, in the aforementioned DE-A-198 52 320, can thus be dispensed with, and the methods according to the invention thus make a considerable simplification with regard to measurement accuracy and the expenditure on measurement technology and a clear one Improvement of the robustness, reliability and drift stability.
- the present invention allows an almost trouble-free temperature determination even with high system dynamics, ie with high heating and / or cooling rates of the wafer and in particular at low wafer temperatures, which is a prerequisite for the reliable control of the rapid heating system and thus the temperature of the semiconductor wafer, since any frequency components (Fourier components) which result from the system dynamics are also contained in the predicted values of the model of the method according to the invention.
- the actual modulation frequency of the radiation sources can be separated, which considerably improves the susceptibility to malfunction and the performance of the rapid heating system, particularly at high heating rates. Heating rates of up to 500 ° C can already be reliably achieved in the laboratory and partly in the area of mass production of chip production.
- the method according to the invention therefore preferably manages with a pyrometer (or radiation detector) for measuring the wafer radiation, since information such as the radiation source intensity (for example the lamp radiation) is provided from the model.
- the radiant heater in order that, for example, the radiation source intensity can be extracted from the model with sufficient accuracy, the radiant heater must be modeled with sufficient accuracy. If it is not possible to model the radiant heaters with sufficient accuracy, the radiation source intensity can be determined, for example, by means of a further radiation detector, for example by means of a pyrometer, which directly determines the radiation source intensity with sufficient accuracy, for example, by using suitable aperture means, such as those used by the applicant previous patent application DE 19852321 are described. However, the radiation source intensity can also be determined, for example, by measuring a variable which is related to the intensity of the radiation source, the radiation source intensity then being obtained by means of suitable conversion data.
- the radiation source intensity can also be obtained with the aid of an observer or an adaptive observer, which comprises a radiation source model.
- the measured variable serves to correct the state of the radiation source state and / or to adapt parameters of parameters of the radiation source model.
- 8 schematically shows the relationship between an input variable u (t) and a measured variable y (t) for determining the radiation source intensity.
- An input signal u (t) is applied to a controller 200 (controller) which regulates the radiation sources 220, for example lamps, in accordance with the input signal.
- a driver 210 is located between the controller and the radiation sources and provides the corresponding power for operating the radiation sources in accordance with the input variable u (t).
- the radiation sources for example halogen lamps, then emit the intensity I B B over a broad band, with some of radiation reaches the wafer 230.
- the wafer is thereby heated and, for example, a narrow-band signal I N B, which is used to determine the wafer temperature, is then determined using the wafer pyrometer.
- the radiation source intensity is not determined by means of a sufficiently precise modeling of the radiant heaters using only the input signal u (t), then, as mentioned above, further measured variables y (t) such as lamp voltage V and / or lamp current I and / or lamp radiation intensity (broadband IBB and / or narrow-band l NB ) are used to determine the radiation source intensity, and as mentioned, these measured variables y (t) can also be used to compare a radiation source model from which the radiation source intensity is then obtained.
- further measured variables y (t) such as lamp voltage V and / or lamp current I and / or lamp radiation intensity (broadband IBB and / or narrow-band l NB ) are used to determine the radiation source intensity, and as mentioned, these measured variables y (t) can also be used to compare a radiation source model from which the radiation source intensity is then obtained.
- the first difference is preferably returned via a first evaluation function and a first control algorithm and / or the second difference is returned via a second evaluation function and a second control algorithm.
- the evaluation functions represent a measure of the correspondence of the measured and predicted signal.
- the control algorithm determines how the respective difference influences the model, taking into account the evaluation function, i.e. how the states and / or parameters of the model are changed in order to achieve the state correction and / or parameter adaptation so that the predicted value and measured value match as closely as possible , In order to be able to compensate deviations of low frequency more effectively, it is often advantageous to use integrators in the feedback branches in addition to proportional corrections by means of feedback matrices.
- controlled variable The determination of a difference and its return to the system model for state correction or for parameter adaptation is generally also referred to in this application as the determination of a controlled variable with which the model states or model parameters are influenced.
- controlled variable is thus expanded compared to the term “controlled variable” which is used in control engineering and which means a system output variable to be controlled by means of a controller.
- the RTP system is a rapid heating system with which an object, preferably a semiconductor wafer, with radiation sources (radiant heaters such as, for example Halogen lamps) is heated, and / or the model comprises at least one object heated in the RTP system, for example at least one semiconductor wafer, and forms a system model.
- radiation sources radiatant heaters such as, for example Halogen lamps
- the model comprises at least one object heated in the RTP system, for example at least one semiconductor wafer, and forms a system model.
- Such an RTP system is usually referred to as a cold wall reactor because the heating of the wafer (object) takes place essentially via the radiant energy of the radiant heaters and the wall of the RTP system is cold in the sense that the temperature of the wall is significantly lower is than the temperature of the wafer.
- the RTP system can also be a hot-wall reactor in which the wall of the RTP system or the process chamber in which the object to be processed (for example the wafer) is located, usually at a higher temperature than the object to be heated is located.
- the RTP system preferably comprises different radiant heaters which are each controlled by means of a control variable, the radiant heaters (or generally the radiation sources) for their modulation of the radiated radiation intensity being controlled by the control variable with different modulation parameters, preferably by several
- model parameters of the system model in a clear manner, such as the transmissivity or reflectivity of a wafer. This is because the system model preferably takes into account the optical properties of the wafer by means of model parameters, in which case the optical properties of the wafer in the system model match the real optical properties of the
- Wafers are aligned in the rapid heating system.
- the radiant heaters can also be combined in groups, the respective groups then being controlled with one control variable each.
- the modulation of the radiation sources can also be achieved or represented by continuous, not necessarily periodic, excitation, for example these can be generated excitations are caused by pseudo-random sequences (random suggestions) or colored noise, these sequences or the noise being fed specifically to the manipulated variable of the radiant heater (or generally to the radiation source or sources).
- the non-periodic excitations can also be caused by parasitic excitations in the system (for example, by disturbances), which affect the manipulated variable of the radiant heater. In these cases, too, the present invention enables sensible parameter adaptation.
- the measurement variable comprises at least one thermal radiation coming from the semiconductor wafer, which is detected by a radiation detector, preferably a pyrometer.
- the heat radiation can, however, also be determined in another way, for example by means of a thermocouple which is spaced apart from the wafer and which measures a temperature change caused by the heat radiation, for example a blackened surface.
- a pyrometer enables precise determination of the radiation intensity and works without contact.
- the radiation signal detected by the pyrometer comprises at least a portion of the heat radiation of the wafer emitted by a measuring area on the semiconductor and radiation of the radiation sources reflected on the wafer and, depending on the wafer material and the wafer temperature, radiation transmitted through the wafer.
- the radiation from the radiation sources preferably has a modulation which allows a distinction to be made between the direct thermal radiation of the wafer. It is thus possible for the radiation reflected on the wafer and / or that caused by the wafer. identify transmitted radiation by means of modulation parameters of the radiation source modulation, as is described in more detail, for example, in the patents US Pat. Nos. 6,191, 392 and 6,396,363, whereby in the present method, as already mentioned, measurement of the radiation source intensity can be omitted.
- the measured variable comprises an alternating component which is essentially dependent on the optical properties of the wafer and which is generated by the modulation of the radiation sources, with which an adjustment of the optical properties (preferably emissivity and / or transmissivity and / or reflectivity) can be carried out by an algorithm which adjusts the alternating component in the detected measured variable and in the measured variable predicted by the system model by adapting the optical properties of the wafer (object) in the system model.
- an adjustment of the optical properties preferably emissivity and / or transmissivity and / or reflectivity
- the measured variable comprises radiation coming from an object, for example contactlessly using a pyrometer, and / or the measured variable detects the temperature or a measured variable related to the temperature of the object by direct contact, for example by means of a thermocouple.
- the object is related to the object, the semiconductor wafer, in such a way that a change in temperature of the object (semiconductor wafer) results in a change in temperature or in a change in the measured quantity of the object, such that, for example, by means of a model and / or a function from the knowledge of the state (for example temperature or a measured variable or the measured variable related to the temperature) of the object, the temperature and / or the state of the object (wafer) can be concluded.
- the object can be, for example, a second wafer or a “cover plate”, which is attached somewhat at a distance from the wafer above and / or below the actual wafer, as is shown in US Pat. No. 6,051,512 or in US Pat. No. 6,310,328.
- the object can furthermore, for example, be an area of the process chamber, an at least part of the wafer radiation reflecting surface located in the vicinity of an object or wafer side, an area of a quartz disk (eg which is part of a quartz process chamber) which is arranged in the vicinity of the object or an object additionally introduced into the process chamber, which reacts sensitively to any temperature changes and / or to the temperature of the wafer (object) with regard to its measured variable.
- the RTP system preferably also comprises at least one heating device which is modulated with respect to the heat energy it emits , and the measured variable on an object e is determined, which due to its thermal properties (such as thermal mass) and / or its thermal coupling to the modulated heating device (e.g.
- a relative parameter such as a modulation amplitude divided by the amplitude of the overall signal
- the object preferably comprises or is a semiconductor wafer, an encapsulation at least partially surrounding at least one semiconductor wafer (for example a graphite box, as are known from the patents US Pat. No. 5,837,555, US Pat. No.
- the determination of the prediction value of the measurement variable comprises the determination of a prediction value of the wafer radiation that predicts a portion of the pyrometer signal caused by the wafer radiation, that is to say the portion of the wafer radiation in the region of the measurement spot on the wafer that contributes to the measurement signal of the radiation measuring device , Since the detected signal comprises both a radiation component from the wafer and radiation components from the radiation sources, ie the radiant heater, the separation of the wafer and radiant heater components is advantageous for a clear state correction. The state reconstruction or in other words the correct interpretation is based on model predictions of both radiation components.
- the prediction of the signal portion of the wafer preferably includes determining an intensity value of the thermal radiation of the wafer in the range of a measurement wavelength of the pyrometer based on the determined State variables and a determined emissivity of the wafer.
- the predicted value of the wafer radiation is then preferably determined on the basis of a model, taking into account the previously determined intensity value of the wafer radiation in the range of the measuring wavelength of the pyrometer and a determined emissivity of the wafer.
- the portion of the pyrometer signal caused by the wafer can thus be advantageously predicted.
- the model takes into account the chamber's influence on the effective emissivity of the wafer, since the chamber geometry and reflectivity of the chamber walls can apparently increase emissivity.
- the determination of the prediction value of the measurement variable comprises, in addition to the determination of the wafer prediction value, also the determination of a lamp prediction value (radiation source prediction value) or in general.
- a prediction value of the radiation from the radiation sources detected on the radiation measuring device which are preferably lamps such as halogen lamps of any shape, flash lamps and / or arc lamps of any shape or laser light sources.
- radiation sources can also be hot surfaces such as heated plates.
- the lamp prediction value or radiation source prediction value predicts a portion of the pyrometer signal or detector signal caused by the radiation sources.
- Determining the lamp (radiation source) prediction value based on the interaction between the wafer and radiation sources (lamps) preferably comprises determining a broadband intensity value of the thermal radiation of the wafer on the basis of the determined state variable (for example the wafer temperature), taking into account an emissivity of the wafer.
- the radiation interactions or other heat coupling mechanisms such as, for example, heat convection and / or heat conduction between different objects (for example lamps, wafers, quartz elements within the process chamber) can generally be used or the process chamber or parts thereof) are taken into account.
- the determination of the lamp prediction value further comprises the determination of an intensity value for the radiation sources on the basis of a lamp model or radiation source model and the control variable of the radiation sources. Since the states of the radiant heaters do not exclusively depend on their manipulated variable but are also generally linked to one another via broadband radiation interactions, it is advantageous to take interactions between different radiant heaters into account in order to improve the accuracy of the prediction of the states of the radiant heaters.
- the lamp or radiation source model preferably takes into account interactions between the individual radiation sources with one another and / or with the wafer, in which the broadband intensity value of the thermal radiation of the wafer is incorporated into the input variable of the lamp radiation source model. Furthermore, the lamp model preferably takes into account interactions between the individual radiation sources, for example between the lamps of a lamp bank consisting of a plurality of lamps. Both the semiconductor wafer and the different radiation sources have interactions with one another on the respective intensity value of a radiation source. The interactions always have a delayed effect on the intensity value of a radiation source. In addition to the power input defined via the manipulated variable, the radiation interactions cause an additional power input that, like the manipulated variable, determines the temporal development of the radiator state. By taking these interactions into account, for example in the lamp or radiation source model, particularly precise intensity values for the individual radiation sources can be predicted.
- the radiation sources are therefore preferably grouped together and the determination of the Intensity value takes place for the respective groups.
- the intensity value for the respective groups is determined using at least one, but preferably at least two, representatives of the group in order to achieve greater accuracy.
- the radiation sources are preferably controlled at least within a group with the same control variable.
- a model is preferably used which predicts the portion of the lamp radiation reflected on the wafer and possibly transmitted through the wafer, which falls into the field of view of the pyrometer, on the basis of the determined intensity value of the radiation sources and one determined emissivity of the wafer.
- the model preferably determines the reflectivity and, if appropriate, the transmissivity of the wafer on the basis of the emissivity determined, in order to determine the reflected and transmitted portion of the lamp radiation.
- the model preferably takes into account the chamber geometry in order to take multiple reflections into account.
- the prediction value of the measurement variable is preferably formed by adding the wafer prediction value and the lamp (radiation source) prediction value, which together should predict the measurement signal of the pyrometer.
- the predicted value of the wafer radiation essentially contains a constant component of the predicted value of the measured variable and the lamp predicted value essentially contains a constant component and an alternating component of the predicted value of the measured variable.
- the alternating component of the predicted value of the measurement variable essentially results from the modulation of the radiation from the radiation sources and the component of the radiation reflected from the radiation sources on the wafer, which is intended to enable the two signals to be distinguished.
- the predictive value of the measured variable is preferably used at least in part.
- Predicted value of the measured variable preferably filtered to determine its alternating component, which is essentially the modeled component of the corresponds to radiation originating from the radiation sources and reflected on the wafer.
- an adaptive algorithm is preferably used which compares the alternating component (for example> 1 Hz) of the predictive value of the measured variable and an alternating component of the radiation coming from the semiconductor (which originates from at least one measuring spot on the semiconductor wafer) detected by the pyrometer. Since this adaptation algorithm only compares the alternating components, the adaptation succeeds regardless of the state of the real system and the system model. Therefore the adaptation algorithm and the state correction do not influence each other.
- this is preferably set in rotation relative to the lamps or radiation sources, the rotation (rotation) being an alternating component of the radiation coming from the semiconductor wafer, for example due to inhomogeneities on the wafer (object or substrate) ) Surface, or inhomogeneities (optical fluctuations, ie inhomogeneities with regard to transmission and / or reflection) on a rotating wafer support device (wafer carrier) which holds the wafer and can possibly set it in rotation.
- This alternating component is taken into account for the determination of a good emissivity value, i.e.
- the emissivity determined is then scaled before it is fed to other processes in order to provide compatibility with regard to the values used.
- the semiconductor wafer in the model for determining the state variable is regarded as a so-called black body, so that an emissivity determination is not necessary for determining the state variable, and the model only requires the control variable of the radiation sources and the specific state correction. to determine the state variable.
- the models used in the present invention can be based on physical models, ie the models describe the underlying physical effects as precisely as possible, or they can be empirical, ie described using a system transfer function, for example. A description of the models using neural networks can also be advantageous.
- several sub-models are preferably used, which only in their entirety and by means of their mutual interaction form an overall model of the object (substrate) and rapid heating system.
- Figure 1 is a schematic representation of a rapid heating system, in which the inventive method can be used.
- Fig. 2 is a schematic representation of part of the rapid heating system according to FIG. 1, in which the angle of incidence or opening angle of a
- Rapid heating system is shown on the measured signal of the radiation sensor;
- 3 shows a schematic illustration of a temperature control in an RTP system;
- Fig. 4 is a block diagram showing a flowchart for determining a
- FIG. 5 shows a schematic illustration of a partial aspect when determining the wafer temperature in a rapid heating system
- FIG. Fig. 6 is a schematic representation of a further aspect in the
- Fig. 7 is a schematic representation of functional blocks of a
- Rapid heating system is used and 8 shows a schematic representation of the relationship between an input variable u (t) and a measured variable y (t).
- FIG. 1 shows a schematic illustration of a rapid heating system 1 for the thermal treatment of a semiconductor wafer 2.
- the rapid heating system 1 has a housing 4 consisting of an upper wall 6, a lower wall 7 and a side wall 8 arranged between them.
- the walls 6, 7 and 8 together form a chamber 10.
- the chamber 10 is through two quartz plates 12 in an upper chamber area 14, a middle chamber area 15 and a lower chamber area 16 divided.
- a plurality of radiation sources 18 in the form of halogen lamps are provided in the upper and lower chamber regions 14, 16.
- other radiation sources such as, for example, arc lamps, flash lamps or lasers, can also be provided, the radiation sources having a high dynamic range in order to enable the wafer 2 to be heated up quickly.
- the quartz plates 12 are essentially transparent to the radiation from the radiation sources 18.
- the middle chamber section 15 forms a process chamber 15 in which the wafer 2 is received via a suitable holding device, not shown in detail.
- the holding device may comprise a rotation device for rotating the wafer 2, which is capable of rotating the semiconductor wafer 2 within the process chamber, i.e. to rotate the wafer relative to the radiation sources.
- the side wall 8 has an input / output opening 20 for loading and unloading the semiconductor wafer 2.
- the input / output opening 20 can be closed by a suitable mechanism, not shown in detail.
- a gas inlet opening 22 for introducing a gas into the central chamber section 15, i.e. the process chamber section.
- a compensation ring 24 is also preferably provided within the process chamber 15, which is capable of during the to compensate for thermal effects occurring with regard to temperature distribution over the wafer.
- An opening for introducing a radiation measuring device 26, in particular a pyrometer, is preferably provided in the lower housing wall 7.
- the pyrometer 26 has a field of view directed towards the wafer 2, which is shown with a dashed line in FIG. 1.
- the field of view is arranged and has an aperture angle such that radiation directly from the radiation sources does not fall into the field of vision of the pyrometer 26, or such radiation is only detected to a very reduced extent by the pyrometer.
- radiation from the radiation sources reflected on the wafer 2 can fall into the field of view of the pyrometer 26, as is shown schematically in FIG. 2 by means of the beam C.
- FIG. 2 schematically shows a partial area of the rapid heating system 1, and in particular different radiation components that fall into the field of view (alpha) of the pyrometer 26.
- thermal radiation originating from wafer 2 falls into the field of view of the pyrometer, provided that it comes from a point in the direct field of view of pyrometer 26, as shown by arrow A in FIG. 2.
- heat radiation from the wafer 2 falls into the field of view of the pyrometer 26, which is reflected on the lower chamber wall 7 and on the wafer 2 itself, as shown by the dashed arrow B.
- radiation originating from the radiation sources 18 also falls into the field of view of the pyrometer, in which it is reflected on the wafer 2, as shown by the arrow C.
- the wafer 2 is essentially opaque to the radiation from the radiation sources 18. If this is not the case, radiation originating from the upper radiation sources 18 can also fall through the wafer 2 into the field of view of the pyrometer 26.
- the radiation from the radiation sources 18 has a modulation.
- the modulation is chosen such that the heat radiation of the wafer 2 does not follow this modulation.
- radiation sources arranged above and below the wafer can have different types of modulation such as modulation frequency and / or modulation phase.
- FIG. 3 shows a schematic representation of a temperature control of a rapid heating system which uses a temperature determination according to the present invention.
- the rapid heating system which is also referred to as an RTP system (rapid thermal processing system) is represented by block 30.
- a sensor signal goes from block 30 to a block 32, in which a temperature determination according to the present invention takes place.
- the sensor signal is preferably the signal of the pyrometer 26, which contains both an alternating component and a direct component.
- the alternating component essentially originates exclusively from the lamp radiation reflected on the wafer, while the direct component originates both from the thermal radiation of the wafer and from the lamp radiation reflected on the wafer.
- An opaque wafer is present in silicon wafers at temperatures above 600 ° C, so that any radiation transmitted through the wafer e.g. from a radiation source above the wafer is no longer relevant.
- the temperature of the wafer is determined by the method described in more detail below.
- the determined temperature which should represent the actual temperature of the wafer (Tj S t) as best as possible, is forwarded to a control unit in block 34.
- the control unit in block 34 compares the actual temperature (T
- the control unit in block 34 can have any controller, such as a PID controller or a model-based controller that includes forward control. In any case, the value of the control signal U eff is also forwarded by the control unit in block 34 to block 32 in order to be used for the temperature determination.
- the temperature determination in block 32 is explained in more detail below with reference to FIGS. 4 to 7.
- FIG. 4 shows in block diagram form the currently preferred embodiment of a temperature determination method.
- the actual temperature is determined in block 40.
- the wafer temperature is determined using a static chamber model, which is a model of the chamber, the at least one model of the chamber properties, preferably a model of the objects in the chamber, preferably, for example, a wafer model and optionally a lamp - or radiation source model.
- a static chamber model which is a model of the chamber
- the at least one model of the chamber properties preferably a model of the objects in the chamber, preferably, for example, a wafer model and optionally a lamp - or radiation source model.
- at least partially idealized parameters are preferably used for the individual models.
- the wafer in the wafer model is viewed as a black emitter or so-called black body with an emissivity of one.
- the effective voltage applied to the entirety of the lamps (U e ff lamps complete), which is fed in, for example, by the control unit 34 according to FIG.
- the determined wafer temperature is also adapted on the basis of a state correction (controlled variable) Z.
- This status correction can be understood as a kind of control loop, since a difference or a correction value is determined from measured values and predicted by the model (the observer) analogously to a target / actual value comparison, the manipulated variable of a controller corresponding to the status correction.
- any radiation source parameter can be used which is suitable for making statements about the energy emitted by the radiation source. So, for example the current or even directly measured radiation quantity ⁇ by which the radiation from the radiation sources can be determined can be selected.
- the state correction (controlled variable) Z is in turn determined in block 42 and is proportional to a difference between a measured wafer pyrometer signal (DC + AC) compi.-g ⁇ m. and a predicted wafer pyrometer signal (DC + AC) com pi.-vor ..
- the block 42 can be designed as a so-called P controller, the correction would then be proportional to the error. To compensate for low-frequency residual errors, however, at least one I controller is usually added. Of course, the controller can also be designed as a PID controller.
- the measured wafer pyrometer signal corresponds to the sensor signal from block 30 to block 32 according to FIG. 3. This wafer pyrometer signal contains a DC component and an AC component.
- the DC component is essentially formed by radiation reflected on the wafer, as shown by arrow C in FIG. 2.
- the DC component contains wafer radiation, ie heat radiation from the wafer and a DC component of the lamp radiation reflected on the wafer and / or on the chamber walls of the process chamber and / or the housing.
- the predicted wafer pyrometer signal is a signal that afer from a predicted value of the wafer radiation DC. and a lamp prediction value (AC + DC) La P enrefi.-prev. is formed.
- the prediction value of the wafer radiation essentially contains only a DC component, while the lamp prediction value contains a DC and AC component.
- the predicted value of the wafer radiation is determined from the wafer temperature T wa fe determined in block 40. certainly.
- the determined wafer temperature is first forwarded to a block 44.
- a predicted intensity of the wafer radiation in the pyrometer measurement range, for example at 2.3 ⁇ m, is determined in block 44. The determination is made on the basis of the wafer temperature T wafer and a determined emissivity E wafer - scale of the wafer. The determination of the emissivity is explained in more detail below.
- the predicted intensity of the wafer radiation lwafer-2,3 is then forwarded to block 46.
- the portion of the wafer radiation in the pyrometer signal is predicted, the portion being essentially an equal portion, but possibly also containing an alternating portion.
- the prediction is carried out using a model in which the intensity of the wafer radiation in the pyrometer measuring range (lwafer-2,3) and the emissivity E wafer - ska i determined . enter as variable sizes.
- the model also contains a model that takes into account the influence of the chamber on the apparent emissivity of the wafer, ie an apparent increase in emissivity due to the reflection properties of the process chamber or the chamber walls.
- the predicted portion of the wafer radiation in the pyrometer signal DC wa fer-vor h . represents the prediction value of the wafer radiation and is passed to an adder in block 48 where it is added to the lamp prediction value to give the predicted wafer pyrometer signal (DC + AC) Ko mp .et - prev . to obtain.
- the lamp prediction value is determined separately from the prediction value of the wafer radiation.
- the intensity of the lamp radiation is determined on the basis of the effective voltage applied to the lamps or another suitable radiation source parameter using a lamp (radiation source) model, specifically in block 50.
- the effective voltage applied to the lamps is determined, for example, from the Control unit in block 34 shown in FIG. 3 to block 50.
- the intensity of each individual lamp of which, for example, over fifty can be provided in the rapid heating system, is not determined.
- the lamps are preferably divided into different groups, for example four groups, the lamps of each group being driven essentially with the same lamp voltage.
- the intensity value for the respective groups is determined using at least two representatives of the group.
- the lamp model is designed in such a way that it takes interactions between the respective lamp filaments into account.
- the lamp model also takes into account interactions between the respective lamps and the Wafer radiation. Therefore, when determining the intensity of the lamp radiation, in addition to the applied effective voltage of the lamps, a predicted broadband intensity Iwafer-prev. the wafer radiation entered into the lamp model.
- the predicted broadband intensity of the wafer radiation is determined in block 52, specifically on the basis of the wafer temperature T wa fer determined in block 40 and possibly the emissivity determined.
- the components that go into the lamp model are shown again in FIG. 7 for clarification.
- the circle 54 forms the actual lamp model.
- the lamp radiation is derived from the lamp model, as represented by the circle 56.
- a correction parameter from block 60 also takes into account the lamp model 54, which takes into account interactions between the individual lamp filaments of the lamps, in particular between adjacent lamps. These interactions are indicated schematically in the diagram shown in the lower right corner in FIG. 7.
- a second correction parameter from the circle 62 also takes into account the lamp model 54, which takes into account interactions between the lamp filament and the wafer 2. These interactions are also indicated in the schematic representation.
- the respective interactions between the lamp filaments with one another and between the lamp filaments and the wafer are determined in advance using a reference sensor, as represented by the circle 64.
- a reference sensor as represented by the circle 64.
- the determination of the lamp prediction value is further explained.
- the one determined in block 50 Intensity of the lamp radiation l ⁇ on p e n is then passed to block 66th
- the predicted portion of the lamp radiation in the pyrometer signal is determined.
- the determination is made by a model that lamps the intensity of the lamp radiation and the specific emissivity Ewafer-s k ai. of the wafer used as input variables.
- the model includes a weighting for the proportion of the individual lamps, since the different lamps have a different influence on the pyrometer signal.
- the model takes into account the portion of the lamp radiation in the pyrometer measurement range that is reflected on the wafer and falls within the field of view of the pyrometer, the model taking into account the reflectivity of the wafer and the chamber geometry.
- the reflectivity of the wafer in turn becomes the specific emissivity E wa fer-skai. determined. Essentially, the reflectivity of the wafer is equal to one minus the emissivity if the wafer is opaque to the lamp radiation.
- the predicted proportion of lamp radiation in the pyrometer signal (AC + DC) ia m penrefie t ⁇ o ⁇ -vor. is supplied as a lamp prediction value to the adder in block 48 and added there with the prediction value of the wafer radiation.
- the lamp prediction value contains a direct component and an alternating component, the alternating component originating from a modulation of the lamp intensity, for example by modulating the effective applied voltage.
- the prediction value of the wafer radiation is added to the lamp prediction value in block 48 by the predicted value
- Block 42 becomes a difference between what is actually measured
- the wafer pyrometer signal and the predicted wafer pyrometer signal are determined and a state correction (controlled variable) Z is determined therefrom, which in turn has an influence on the determined wafer temperature T wa f er in block 40.
- the system is designed in such a way that the difference converges to zero as the above loops continue to run. As soon as the difference is zero or within a predefined tolerance interval, it can be assumed that the determined wafer temperature T wafer corresponds to the actual wafer temperature.
- a "determined emissivity" was used as the input variable. How the determined emissivity can be determined is explained in more detail below with reference to FIG. 4.
- a prediction value of the wafer radiation is in block 48 of FIG. 4 adds a lamp forecast value to a predicted Waferpyrometersignal (DC + AC) ko mpi. forecast. to obtain.
- This predicted wafer pyrometer signal which has both an alternating and a direct component, is passed to a filter in block 90, in which the direct component is filtered out.
- the signal emerging from block 90 thus only contains an alternating component which essentially originates exclusively from the modulation of the lamp radiation.
- This signal is called AC.ampen-prev. designated.
- This signal is passed on as an input variable in block 92.
- a filtered portion of the measured wafer pyrometer signal is passed into block 92.
- the measured wafer pyrometer signal (DC + AC) k0 r ⁇ .pi.- g ⁇ m. passed through a filter in block 94 to filter out the DC component.
- the resulting signal corresponds to the measured alternating component of the wafer pyrometer signal AC in accordance with , which is also passed as an input variable into block 92.
- An emissivity value for the wafer is determined in block 92 from the measured alternating component of the wafer pyrometer signal and the predicted alternating component of the wafer pyrometer signal.
- an adaptive algorithm first adapts the optical properties of the system model (including e.g.
- the adaptation algorithm only uses and compares the alternating components of the measured wafer pyrometer signal and the predicted wafer pyrometer signal, the adaptation succeeds regardless of the state of the real system and the system model, in particular regardless of the temperature of the wafer (object). After the adaptation, the optical Properties and in particular the emissivity can be taken or tapped from the system model.
- the wafer rotation can generate an alternating component corresponding to the rotational speed, which in turn can be taken into account when determining the emissivity value in block 92.
- the alternating component corresponding to the rotational speed can be filtered out.
- the emissivity value E wa f er determined in block 92 is now passed on to block 94, in which it is scaled for subsequent processes, and as E wafe r- ska ⁇ . is delivered to subsequent determination processes.
- the emissivity determination essentially only the emissivity in the measuring range of the radiation detector used, such as, for example, the wafer pyrometer 26, which is, for example, 2.3 ⁇ m, is determined.
- This determination assumes that the alternating components of the radiation signals of the measurement and of the prediction, which originate primarily from the modulation of the radiation sources, are essentially generated by reflection on the wafer or reflection on the chamber walls. Therefore, the reflectivity of the wafer is an important factor in the adaptation of the optical properties described above by the adaptation algorithm.
- the transmissivity of the wafer can also play an important role, provided that the wafer is not opaque to the radiant heat.
- FIG. 5 shows a simplified illustration of a system for determining the temperature of a semiconductor wafer in a rapid heating system, or for determining a state or a state variable. 5, the same reference numerals are used as in the previous figures, provided that similar or equivalent elements are described.
- FIG. 6 shows a simplified illustration for determining the emissivity or for determining model parameters.
- the determination of at least one state variable for example the wafer temperature
- the determination or adaptation of at least one model parameter for example the emissivity
- the adaptation or adaptation of the model parameters takes place by means of an adaptive observer, which is described schematically in FIG. 6 by the function blocks 104, 102, 112, 110 and 108.
- the state determination and the parameter adaptation are described again separately from one another by means of the observers shown schematically in FIGS. 5 and 6, the state determination and parameter adaptation taking place in parallel in the inventive method according to FIG. 4.
- a sequential execution of the status and parameter determination would also be possible, e.g. Different measured variables and their predicted values are determined in succession, i.e. e.g. that AC and DC components of a measurement signal, in contrast to the embodiment in FIG. 4, are determined one after the other and used to determine the state or parameters.
- a rapid heating system 1 with heating lamps 18 is shown schematically.
- a semiconductor wafer 2 is arranged in the rapid heating system 1 for its thermal treatment.
- a pyrometer 26 is directed to one side of the wafer 2.
- the heating lamps 18 are controlled via a control unit 70.
- the measurement signal is forwarded to the block 72.
- the measurement signal is also shown schematically at 74.
- a model of a rapid heating system 1 ' is shown in the dashed box 76.
- the features of the model rapid heating system are each marked with an apostrophe.
- the model of the rapid heating system 1 ' includes, for example, a model of the lamps 18', a model of the wafer 2 ', a model of the chamber 4' and a model of the pyrometer 26 '.
- the control signal of the heating lamps 18 is input into the model of the rapid heating system 1, as shown by the dashed line 78.
- a temperature T of the wafer 2 ' is specified in the model as system 1', which influences the states of the wafer model or the states of the other models and / or the model of the Wafer 2 'or the other models.
- the model of the rapid heating system 1' calculates a predicted pyrometer signal (DC + AC) k om P ⁇ . - vo r h. and transmits this to block 82.
- the measured pyrometer signal from block 72 and the predicted pyrometer signal 82 are both transmitted in block 84 where a difference between these two values is calculated. From the difference, a state correction (controlled variable) is then determined, which is transferred to block 80 by the temperature variable T (which results as a state variable of a state of the model or models) of the wafer 2 'in the model, taking into account the state correction change.
- the temperature T is also output from the model to the circuit 86 and can be used outside the model, for example for temperature regulation or temperature control.
- the modeled wafer temperature T in circle 86 corresponds to the actual wafer temperature, which can thus be determined precisely using a single wafer pyrometer 26.
- the actual radiation intensity shown at 74 is contrasted at 88 with the modeled radiation intensity, which according to the model can be divided into a wafer radiation and a lamp radiation, since the respective contributions can be identified from the model predictions.
- FIG. 6 shows an alternative representation of a system for determining emissivity in accordance with the present invention, the structure of the representation being similar to that of FIG. 5. Therefore, the same reference numerals are used in FIG. 6 as in FIG. 5 if the same or equivalent parts are described.
- 6 again shows a schematic illustration of a rapid heating system 1 with a housing 4, as well as radiation sources 18 and a semiconductor wafer 2 accommodated therein. Furthermore, a pyrometer 26 is again shown. The heating lamps 18 are in turn controlled by a control unit 70.
- the actually measured radiation intensity of the pyrometer 26 is shown, only the alternating component being shown in FIG. 6.
- This alternating component AC ge m. is also forwarded to a block 102 by the pyrometer 26.
- a model of the rapid heating system is again shown in block 104, the model elements being provided with an apostrophe.
- the model of the rapid heating system 1 ' comprises a model of the wafer 2', the chamber 4 ', the heating lamps 18' and the pyrometer 26 '.
- the drive power of the drive unit 70 is fed into this model, as indicated by the dashed line 78.
- a block 106 is also specified, in which an emissivity of the wafer is set at 2.3 ⁇ m, which enters into the model of the wafer 2 ′ and is output to the oval (interface) 108.
- an alternating component of the pyrometer signal is now predicted AC V0 based on the control power applied to the rapid heating system 1. h .- This signal is transmitted to block 110, and from there to block 112. The signal AC acc . block 102 is also transferred to block 112.
- a difference between that actually measured Alternating component of the pyrometer signal and the predicted alternating component of the pyrometer signal are determined, and a control parameter is determined from this difference and is supplied to block 106.
- the emissivity is changed in block 106 as a state variable of the wafer (or more precisely as a parameter of the system model) and both fed into the model of the wafer 2 ′ and output to the oval (an interface) 108. It should be noted that a change in emissivity naturally also results in a change in other optical properties, such as reflectivity and / or transmissivity, in the model, although this is not dealt with in detail.
- the system is in turn constructed so that it tries to reduce the difference AC to zero or to a value within a predefined tolerance interval, so that the modeled emissivity matches the actual emissivity of the wafer.
- a calibration of the lamp model, and in particular the effect of each individual lamp on the model, and the weighting of each lamp with respect to the predicted pyrometer signal can be determined using a calibration method.
- individual lamps can be operated and the lamp radiation emanating from them can be measured. This can be done with and without a wafer in the rapid heating system.
- the weighting factor for the predicted pyrometer signal of the lamps is determined with wafers in the rapid heating system, while without wafers the pure radiation intensity of the lamp is determined at a specific actuation power.
- the model parameters are adjusted to the parameters of the real system and the state of the model also follows that of the real system within narrow limits. Therefore, a state variable, such as the wafer temperature, can be taken directly from the model or tapped from it.
- a method can be integrated in the system described above, in which irregularities on one side of the semiconductor wafer, such as spots to which the pyrometer is directed, are detected before the wafer is loaded into the rapid heating system 1. This can be done by scanning the surface and mapping the irregularities. For example, the individual layers of a stack can be determined by a multi-point measurement. These values are entered in the temperature calculation model so that the irregularities are known and can be compensated accordingly.
- the emissivity of the wafer can thus be calculated at any individual temperature and is available to a corresponding control unit or the model.
- the backside measurement and mapping can be done in real time at room temperature by a spectral typometer while the wafer is waiting for thermal treatment. Another possibility would be a surface reflection measurement and a mapping of the top or the surface, which could also be done at room temperature.
- This method which can provide information for the temperature calculation model, can alternatively also be used in a conventional system for determining the temperature of a wafer.
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Abstract
Description
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JP2005509691A JP4461097B2 (ja) | 2002-12-23 | 2003-11-28 | 高速加熱装置における半導体ウェーハの温度を決定する方法 |
US10/540,613 US7412299B2 (en) | 2002-12-23 | 2003-11-28 | Process for determining the temperature of a semiconductor wafer in a rapid heating unit |
CN2003801099279A CN1754087B (zh) | 2002-12-23 | 2003-11-28 | 用于确定速热设备中的半导体晶片的温度的方法 |
AU2003292147A AU2003292147A1 (en) | 2002-12-23 | 2003-11-28 | Method for determining the temperature of a semiconductor wafer in a rapid thermal processing system |
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DE10329107.5A DE10329107B4 (de) | 2002-12-23 | 2003-06-27 | Verfahren zum Bestimmung wenigstens einer Zustandsvariablen aus einem Modell eines RTP-Systems |
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DE102006036585A1 (de) * | 2006-08-04 | 2008-02-07 | Mattson Thermal Products Gmbh | Verfahren und Vorrichtung zum Ermitteln von Messwerten |
WO2011029739A1 (de) * | 2009-09-08 | 2011-03-17 | Aixtron Ag | Cvd-reaktor |
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JP4864396B2 (ja) * | 2005-09-13 | 2012-02-01 | 株式会社東芝 | 半導体素子の製造方法、及び、半導体素子の製造装置 |
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- 2003-11-28 US US10/540,613 patent/US7412299B2/en active Active
- 2003-11-28 KR KR1020057011860A patent/KR101018234B1/ko active IP Right Grant
- 2003-11-28 AU AU2003292147A patent/AU2003292147A1/en not_active Abandoned
- 2003-11-28 WO PCT/EP2003/013387 patent/WO2004059271A1/de active Application Filing
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DE102006036585A1 (de) * | 2006-08-04 | 2008-02-07 | Mattson Thermal Products Gmbh | Verfahren und Vorrichtung zum Ermitteln von Messwerten |
DE102006036585B4 (de) * | 2006-08-04 | 2008-04-17 | Mattson Thermal Products Gmbh | Verfahren und Vorrichtung zum Ermitteln von Messwerten |
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Also Published As
Publication number | Publication date |
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AU2003292147A1 (en) | 2004-07-22 |
US20060100735A1 (en) | 2006-05-11 |
KR101018234B1 (ko) | 2011-03-03 |
JP2006512590A (ja) | 2006-04-13 |
US7412299B2 (en) | 2008-08-12 |
KR20050088324A (ko) | 2005-09-05 |
JP4461097B2 (ja) | 2010-05-12 |
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