WO2018166955A1 - Method and device for the thermal treatment of a substrate - Google Patents

Abstract

The invention relates to a device and a method for the thermal treatment of at least one substrate (2) in a process chamber (1) of a treatment device at a regulated temperature with a heat flow from a heating element (5) heating a susceptor (4), to which the heating power (10) is supplied from the outside, through the substrate (2) heated by the susceptor (4) and the process chamber (1), to a cooling element (9) cooling a process chamber cover (7), from which a waste heat flow (26) is outwardly dissipated. The temperature regulation comprises at least one regulating circuit, in which the waste heat flow (26) is the regulating variable, the heat flow being detected by heat flow detection means (20). A variable heat flow resistance is modifiable in order to regulate the heat flow.

Description

 description

Method and device for the thermal treatment of a substrate. Field of technology

[0001] The invention relates to a method and a device for the thermal treatment of at least one substrate in a process chamber of a treatment device at a controlled temperature with a heat flow from a susceptor heating element, the heating power is supplied from the outside, heated by the susceptor Substrate and the process chamber through, toward a process chamber ceiling cooling cooling element, from which a waste heat flow is discharged to the outside.

State of the art

[0002] A generic device is used in semiconductor technology in order to coat substrates with layers, in particular semiconductor layers. The substrates lie on a susceptor or on a susceptor-supported substrate holder that can rotate about an axis. The susceptor is energized by the side facing away from the substrate with energy. A heating element provided for this purpose can be an infrared radiator or an RF coil. The surface of the substrate to be coated points into a process chamber into which process gases are fed, which decompose at least partially after chemical reactions, so that a layer can form on the surface of the substrate. A process chamber ceiling opposite the substrate is cooled by means of a cooling element to a temperature which is considerably lower than the temperature of the susceptor. Due to this temperature difference, a heat flow from the susceptor through the substrate and the process chamber through to the cooling chamber cooled process chamber ceiling forms. The heat flow depends on the heat transfer properties of the heating element and the cooling element arranged elements of the treatment device, wherein the heat transfer properties from the susceptor to the substrate remain substantially unchanged during a coating process at substantially constant process parameters. The thermal conductivity of the heat transport path from the susceptor to the substrate surface is essentially determined by the thermal conductivity of the solids, wherein, in the case of a substrate holder rotating on a gas cushion, the heat transfer through a gas gap must additionally be taken into account. Due to a changed gas flow, the heat transfer also changes. As a rule, this gas gap forms, together with the gas gap between the substrate and the substrate holder, the greatest heat transfer resistance between the susceptor and the substrate.

The heat transfer from the substrate surface through the process chamber to the process chamber ceiling occurs on the one hand by heat conduction through the gas in the process chamber, to a small extent also by convection, but essentially by heat radiation and depends on the emissivity or Reflectivity of the surfaces of the substrate and the process chamber ceiling. In particular, the surface of the process chamber ceiling has an emissivity that changes over time. This is a consequence of a parasitic coating of the process chamber surface, but also a consequence of aging.

The temperature control is carried out with the aim of maintaining the temperature of the surface of the substrate, at which surface the chemical reactions take place, at a constant value, wherein the substrate surface should have the same temperature as possible over its entire surface, the over the entire coating process and must remain constant over the following coating processes. For measuring the surface temperature used in the prior art pyrometers, especially those that operate on a wavelength of 400 nm. With such a pyrometer, the surface temperature of the substrate, but possibly also of the susceptor is optically determined. When using silicon substrates, the surface temperature of the substrate can be determined with such a pyrometer. For sapphire substrates this is not possible. Sapphire is transparent to light of this wavelength. If, for example, a GaN layer is deposited on a sapphire substrate, then only the temperature of the surface of the substrate holder or susceptor below the substrate is measured with such a pyrometer because of the transparency of the substrate. Only when a sufficiently thick GaN layer has been deposited on the substrate can the pyrometer be used to measure the surface temperature of the substrate or of the layer deposited thereon.

In the heat transfer path between the heating element and the cooling element, there are thus several heat flow resistances in the heat flow direction whose size influences the temperature profile between the heating element and the cooling element and thus also the substrate temperature.

Summary of the invention

The invention has the object of developing the genus in modern method or the genus in contemporary device to the effect that in successive growth processes with otherwise the same process parameters, the same substrate temperatures are adjustable.

[0007] The object is achieved by the invention specified in the claims, wherein the subclaims represent not only advantageous developments of the invention specified in the two independent claims, but also independent solutions to the problem. [0008] In a first variant of the invention, a variable heat flux resistance is varied. In this variant is located in the heat transport path from the susceptor to the cooling element and in particular between the process chamber ceiling and the cooling element, an element whose Wärmeleiteigen- schaff, in particular its thermal conductivity, is changeable. The element can be formed by moving parts, for example movable solids. However, the element is preferably formed by a gap through which a purge gas can flow. Through this gap, the heat must flow from the susceptor to the cooling element, so that this gap forms a heat flow resistance. The heat flow resistance can be varied by, for example, gases with different thermal conductivities are fed into the gap. In particular, it is provided to feed into the gap a mixture of two gases which have strongly divergent thermal conduction properties or heat capacities. In particular, a mixture of hydrogen and nitrogen is fed into the gap. The mixing ratio of the two gases is changed in such a way that the heat flow discharged to the outside from the cooling element is kept constant. In this variant, at least two control loops can be provided. A first loop controls the susceptor temperature. The susceptor is preferably heated by an RF heater. Within the susceptor or at the edge of the susceptor is a temperature measuring element. The temperature sensing element may be the end of a light pipe connected to a pyrometer. However, the temperature measuring element can also be a thermocouple, which supplies a thermoelectric voltage, which is used as a controlled variable for the heating power control. The temperature measurement can take place on the side of the susceptor facing the heating. A second control circuit regulates the waste heat flow to a setpoint. Heat flow detection means are also provided here which determine the waste heat flow via the mass flow of the coolant and its temperature or temperature difference between the inlet temperature and the outlet temperature, which flow rate is determined by means of the second control circuit. It is kept constant. The flushable by the purge gas gap extends parallel to the susceptor surface or to the process chamber ceiling substantially over the entire areas of the process chamber, in which substrates are arranged. With a gas flow regulator, the gas mixture in the gap can be changed in such a way that the waste heat flow of the coolant remains constant. The heating element control regulates the heating power. The gap between the cooling element and the process chamber ceiling can be in the range of one millimeter. Due to manufacturing tolerances, the gap width may change when the process chamber ceiling is replaced with another one. With the method according to the Invention also effects of such tolerances on the temperature balance are compensated. Similarly, changes in the emissivity of the gap-limiting surfaces can be compensated. The gap preferably extends between a cooling element and the process chamber ceiling delimiting the process chamber. It is also proposed that in the temperature control also a heat flow characterizing operating parameter is used. The temperature control is influenced according to the invention by the heat flow. According to a further aspect of the invention, it is provided that the temperature control has at least one control loop, in which the heat flow is the controlled variable. In the method according to the invention heating power is supplied to a heating element from the outside. The heating element heats a susceptor. Due to a temperature difference between the susceptor and the cooling element, a heat flow from the heating element to the cooling element is formed. The heat flow passes through the susceptor heated substrate and the process chamber through to the cooling element that cools the process chamber ceiling. According to the invention, heat flow detection means are provided with which the heat flow can be measured at a predetermined location. In a particularly preferred variant of the invention, the waste heat flow is determined and used for temperature control. The device according to the invention has for this purpose an electronic control device which is set up and programmed in such a way that That is, a control parameter determined from the heat dissipated by the coolant is used for temperature control. The cooling element has in particular cooling channels through which a coolant is passed. The coolant can be kept at a constant cooling temperature by a cooling control loop. However, it is sufficient and is preferred if only a constant mass flow of the coolant flows through the cooling channels. The mass flow of the coolant, together with the difference between the outlet temperature and the inlet temperature of the coolant, is a measure of the heat flow. The product of these two quantities and the specific heat capacity of the coolant forms the waste heat flux that is determined. The mass flow can also be varied, for example to keep the outlet temperature of the coolant at a constant value. The waste heat flow is used here preferably at constant coolant flow according to an aspect of the invention as a control variable to keep the temperature of the substrate at a constant value. In a variant, it is provided that the setpoint temperature is initially maintained at a constant value or the required heating power is observed to obtain the setpoint temperature. If, for example, an increase in the heating power compared to a reference value is detected, then the desired value of the temperature can be increased. In a variant, instead of the heating power, the waste heat flow difference can be used to determine a desired temperature correction. The heat flow forms in this variant, at least one controlled variable of the heating element control loop. This takes place, for example, at least for a time in which no reliable value of the substrate surface temperature can be determined with another, in particular optical, temperature measuring device. If the conditions allow the substrate temperature to be optically determined, then the heating power can also be regulated to a target value of the substrate temperature. This variant is used in particular in treatment devices in which one or more substrates rests on a susceptor, which is heated from the rear side via a resistance heating or via an IR heater. The process gases are introduced in particular in this variant preferably via a gas inlet member into the process chamber, which is designed as a showerhead. The showerhead has a gas outlet plate which extends parallel to the process chamber facing surface of the susceptor and having a plurality of gas passage openings through which the process gases can flow into the process chamber. The showerhead is both the process chamber ceiling and the cooling element, but can also be in touching contact with a process chamber ceiling. It has cooling channels through which a coolant flows. The device or the method may have a plurality of interacting control circuits. To avoid that the coolant can heat to impermissible temperatures, a cooling element control loop is provided. In the cooling element control circuit, by varying the mass flow of the coolant, the temperature of the coolant and in particular the outlet temperature of the coolant can be kept at a constant value. However, it is sufficient if the waste heat flow is determined merely by measuring the temperature difference between the inlet temperature and the outlet temperature at a constant mass flow. To control this against a setpoint, the heating power can be changed. This is done with a heating element control loop, which has the waste heat flow as a controlled variable. According to a further aspect of the invention, in which the temperature control is influenced by the heat flow, the setpoint of a heating controller for controlling the heating power is a surface temperature measured on the substrate and / or the susceptor. This can be measured optically by means of a pyrometer. The electronic control device, which in particular is part of a control device, receives the setpoint value for regulating the surface temperature from a nominal value setting device, which in turn receives the setpoint from a recipe programmed into the control. In this variant, the temperature of the process chamber ceiling is explicitly kept at a specific temperature via the purge gas composition, for example to ensure desirable chemical properties. reactions. Changes in the surface emissivity due to process deposition then lead to a deviation of the substrate temperature from the target value, which is compensated by correction of the heating setpoint. The control device determines continuously or at intervals the heat flow and in particular the waste heat flow, in which the heat flow of the coolant is determined. If the heat flow deviates from a predetermined value which has been determined, for example, in a growth process "Golden Run" carried out under standard conditions, then the target value for the surface temperature of the substrate or of the susceptor is varied by means of the desired value setting device Target value of the surface temperature occurs in particular when the heat flow has changed by a predetermined value compared to a standard heat flux. <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> According to the invention, it is possible, if necessary, for the control to be used only briefly, if the layer thickness or the physical property of the layer does not permit its temperature to be optically determined, the desired value of the heating control with a G derived from a heat flow difference correcting the size. For example, it is possible, when depositing a layer whose temperature is easily determinable by means of a pyrometer, to ascertain the current waste heat flux, in order to then determine this during the deposition of an earlier layer of a subsequent process in which the optical temperature determination is not yet possible. to be used as reference value. Also, the heat flow of a successful deposition process can serve as a reference value.

Brief description of the drawings

Embodiments of the invention are explained below with reference to the accompanying drawings. Show it: 1 shows schematically in cross section the process chamber of a treatment device of a first embodiment,

2 is a block diagram of the heat flow path from the heater 5 to the cooling element 9 of the first embodiment,

Fig. 3 is a representation according to Figure 1 of a second embodiment and

Fig. 4 is a representation according to Figure 2 of the second embodiment.

Description of the embodiments

FIG. 1 shows, essentially schematically, the cross section through the process chamber of a CVD reactor, as described, for example, in DE 10 2006 013 801 and the publications cited therein. The device is used for depositing III-V semiconductor layers on substrates. For this purpose, a mixture of two or more process gases is fed into a gas inlet element in the form of a shower head together with a carrier gas. The process gases may be a hydride of an element of the V main group and an organometallic compound of an element of the III main group. For example, to produce GaN layers, trimethyl gallium together with ammonia can be fed into the process chamber, where a III-V layer is deposited on one of the III-V substrates, but preferably a silicon or sapphire substrate. The decomposition reaction of the process gases takes place not only on the surface of the heated substrate 2, but also on the side facing the process chamber 1 side of a gas outlet plate of the showerhead. The gas outlet plate forms the process chamber ceiling 7. The gas outlet plate 9 has gas outlet openings 24 which are arranged like a shower head. Between the gas outlet openings 24 extend cooling channels 13 through which a coolant is passed. The gas inlet member, which forms the cooling element 9, an IR heater 5, a susceptor arranged between the showerhead 9 and the IR heater 5 for supporting the substrates 2, are located within a gas-tight reactor chamber of the CVD reactor.

The reference numeral 6 indicates a measuring point at which the surface temperature of the susceptor 4 can be measured. This is done with a temperature measuring device, which may be a pyrometer. The pyrometer is located outside the process chamber within the reactor housing and is able to visually measure the surface temperature of the substrate 2 and provides a temperature reading 12, which is fed to a heating controller 11, which can use the Temperaturmes s value as a controlled variable to a heating power Feeding 10 in the heating element 5, so that the susceptor 4 and in particular the surface of the substrate 2 heats up to a process temperature. In addition, a measuring point 6 'may be provided to determine the surface temperature of the substrate 2. The temperature measured there can be used, for example, to a setpoint adjustment. Through an inlet 14, a cooling liquid is fed into the cooling channels 13, passes through the cooling channels and leaves the cooling channels 13 through a drain 15. With the thermometer 16, the temperature of the cooling liquid can be measured, which leaves the cooling channel 13. A temperature difference is determined between the measured value of the outlet temperature of the cooling liquid and the inlet temperature of the cooling liquid. With a heat flow measuring device 20, the heat flow can be determined, which flows through the cooling water through the outlet 15 from the cooling element 9 to the outside. For this purpose, the temperature measured by the thermometer 16 can be used. The waste heat flow is designated by the reference numeral 26.

With Rtl a first heat flow resistance is referred to, which is influenced by the thermal conductivity of the substrate 2 and the heat transfer resistance between the substrate 2 and susceptor. This heat flow resistance Rtl remains essentially unchanged during the coating process, provided the other process parameters do not change.

With Rt2 a second heat flow resistance is called, the distance between the substrate surface and the process chamber ceiling 7, ie the underside of the cooling element 9 denotes the heat transfer. The heat flow via the first heat flow resistance Rtl takes place essentially via heat conduction. The heat flow through the second heat flow resistance

Rt2 takes place essentially by thermal radiation and depends on the emissivities of the surfaces of the substrate 2 and the process chamber ceiling 7 or the wall of the cooling element 9 facing the process chamber 1. The emissivity changes during the coating process for several reasons. First of all, the surfaces can age. However, it is also essential that coatings arise on the surfaces that influence the optical properties, such as emissivity and reflectivity. These properties of the process chamber thus also change if the other process parameters, which are essentially set according to the recipe used, remain constant. As a result of a changing second heat flux resistance Rt2, the temperature of the substrate surface may change.

The surface temperature of the substrate 2 can not be measured with a pyrometer, in particular, when the substrate 2 is transparent for the wavelength used, for example, a sapphire substrate is transparent to 400 nm light. When depositing a GaN layer on a sapphire substrate, a reliable measurement of the surface temperature of the substrate 2 or of the layer can only take place when a sufficient layer thickness has been reached. At the beginning of such a layer growth, therefore, the temperature control is not only performed via a temperature measurement value 12, but the setpoint value is corrected via a controlled variable 25, which is influenced by the heat flow. This correction quantity represents a difference of the actual value of the waste heat flow 26 from a desired value.

Instead of the deviation of the waste heat flow, the deviation of the heating power from an expected reference value can also be used to derive a temperature correction. This is preferably done in a device which has a set value setting device 28, with which the set value 29 for the heating controller 11 is varied. With a temperature measuring device, for example a pyrometer, the susceptor temperature 6, in particular the temperature of the surface of the susceptor 4 facing the process chamber, is determined. This forms the setpoint for the heating controller 11, which controls the heating power 10. The surface temperature of the susceptor 4 is controlled against a desired value 29. The desired value 29 is predetermined by the desired value setting device 28. The setpoint presetting device 28 receives the setpoint value 29 from an electronic controller which determines the setpoint value according to a recipe. By means of the heat flow measuring device 20, the waste heat flow 26 is permanently measured. If this deviates by a certain amount from a standard value for a certain time, then the nominal value presetting device 28 will vary the desired value 29, the substrate temperature being increased or decreased. As a result, it is possible to respond to effects that arise due to occupancies on the process chamber ceiling 7. In place of the waste heat, the heating power can generally also be considered.

If the substrate temperature 6 'can be measured, but this can also be supplied as a correction value 25 of the setpoint-setting device 28.

2 shows schematically the heat flow path of the heating element 10 via the two heat flow resistors Rtl and Rt2 toward a cooling element 9. The waste heat flow 26 is measured by a heat flow measuring device 20 and compared with a desired value. From this, a large control 25 is obtained, which is used to control the heating controller 11, the manipulated variable is the heating power 10.

FIG. 3 shows, in a cross-section, schematically the elements of a CVD reactor which are essential for the description of the invention, as described, for example, in DE 10 2009 003 624 A1 or in DE 10 2006 018 514 A1.

The process gases, which may likewise be a hydride of the V main group and an organometallic compound of the III main group, flow into the process chamber 1 through a gas inlet element (not shown in the drawings). This takes place together with a carrier. gergas. The process gases react in the process chamber 1 and in particular the surface of the substrate 2 disposed therein to a III-V layer. As in the first embodiment, the carrier gas and gaseous reaction products leave the process chamber 1 through a gas outlet connected to a vacuum pump, so that a low pressure can be set within the process chamber 1.

A susceptor 4 whose temperature is measured optically with a measuring element, for example a thermocouple 6 or a light pipe, is heated from below by a heating device 5. The heating device 5 may be an RF heater which generates eddy currents in the susceptor 4, so that the susceptor 4 is inductively heated. The temperature measured value 12 obtained by the measuring element 6 is fed to a heating controller 11, which supplies the heating power 10 with which the heating element 5 is operated as a manipulated variable.

On the susceptor 4 is a substrate holder 3. The substrate holder 3 rests in a pocket 17 on a gas cushion 18. The gas flowing into the gas cushion 18 is capable of rotating the substrate holder 3 about an axis. On the substrate holder 3 are one or more substrates. 2

In a coating process, the first heat flow resistance Rt1 changes essentially little or only slightly under the same process parameters. However, if the process parameters change, the heat flow resistance Rtl may also change. If the gas, which is fed into the gas gap forming the gas cushion 18, changed in terms of its heat transfer properties, so does Rtl. Although the coating steps following each other in a recipe are each carried out with different process parameters, because layer sequences with different layers are deposited on one another. The process steps, which are in the same position in the same recipe but have the same process parameters.

The process chamber 1 is bounded below by the substrates 2 and up through a process chamber ceiling 7, for example. Graphite. The process chamber ceiling 7 heats up due to radiant heat emitted by the substrate holder 3 and the substrate 2. The distance between substrate surface and process chamber ceiling 7 forms a second heat flow resistance Rt2, which is influenced by the optical properties of the surfaces of substrate 2, substrate holder 3 and process chamber ceiling 7. The emissivity, reflectivity, and absorbency of these surfaces changes with time, on the one hand, as a result of natural aging and, on the other hand, as a result of coating during the coating process.

Between the process chamber ceiling 7 and the underside of a wall, which is formed by a cooling element 9, a gap 8 is formed, which is purged with a purge gas, which consists of a mixture of two gases, the mutually different thermal conductivities or Have heat capacities.

The cooling element 9 has cooling channels 13, in which an inlet 14 feeds a coolant. The coolant heated in the cooling channel 13 leaves the cooling channel 13 through an outlet 15. The outlet temperature is measured by means of a thermometer 16.

With a heat flow measuring device 20 shown symbolically in FIG. 3, the heat flow 26 is measured. This can be obtained from the heat capacity of the coolant, its mass flow and the temperature difference between inlet temperature and outlet temperature. It is a gas flow regulator 21 is provided, with which the gas flow of two different gases can be controlled in the gap 8. In particular, a gas flow regulator 21 is provided, which can regulate a nitrogen inflow 22 and a hydrogen inflow 23 into the gap 8. By adjusting the mixing ratio between hydrogen and nitrogen, it is possible to influence the thermal conductivity within the gap 8 and thus the size of a third heat flux resistance Rt3. By variation of the heat flow resistance Rt3. By varying the heat flow resistance Rt3, the changing heat flow resistance Rt2 can be compensated. The variation of the heat flow resistance Rt3 takes place independently of component tolerances, which can influence the thermal properties of the gap 8. Thus, different gap heights, but also different emissivities of the gap limiting surfaces can be compensated by the variation of the gas composition. In the embodiment shown in Figure 3, the first heat flow resistance Rtl is determined on the one hand by the gas gap 18, the thermal conductivity of the substrate holder 3, the substrate 2 and the susceptor 4. On the other hand, in the region adjacent to the substrate 2, a heat flux resistance is determined by the susceptor 4 and cover plates 19 resting on the susceptor 4.

Figure 4 shows schematically the heat flow from the heating element 5 to the cooling element 9 influencing heat flow resistances Rtl, Rt2 and Rt3, wherein the heat flow resistance Rt3 is a variable heat flux resistance. He gets his manipulated variable from a control loop whose control variable is the waste heat 26. The latter is kept at a constant value by means of the regulator 21. The equivalent circuit diagrams shown in Figures 2 and 4 represent the actual physical conditions roughly simplified again. The heat flow generated by the heater 5 occurs only in part through the susceptor 4 and the substrate holder 3 as well as through the substrate 2. When viewed, however, this part of the heat flow generated by the heating power 10 can be regarded as constant, so that a substantially constant proportion of the heating power 10 is radiated as radiant heat from the surface of the substrate holder 3 and the surface of the substrate 2 into the process chamber 1. For physical reasons, only a portion of this emitted from the substrate 2 and the substrate holder 3 heat reaches the process chamber ceiling 7. For physical reasons, only a part of the heat coming to the process chamber ceiling 7 through the gap 8 reaches the cooling element. 9

It is considered advantageous that with the device according to the invention and with the method according to the invention, the temperature of the substrate 2 and in particular the surface temperature of the substrate 2 is controlled to a substantially constant value without the temperature must be measured explicitly. According to the invention, thermodynamically relevant properties of the CVD reactor are regulated by a controller such that a heat flow, in particular the waste heat flux 26, is kept at a constant value. The exemplary embodiments show, as examples, the influencing of the heating power of the heating element 5 and the influencing of an additional heat flow resistance Rt3 in the heat transfer path between the heating element 5 and the cooling element 9. The regulators 11, 18, 21 may be separate electronic devices , But it is also possible that these regulators 11, 18, 21 from an electro- nischen, in particular program-controlled control device are formed. The regulators 11, 18, 21 may be PID controllers. In the exemplary embodiment illustrated in FIGS. 1 and 2, the temperature control can optionally also be carried out by means of the temperature sensor 6, provided that this process technology is capable of determining the surface temperature of the substrate 2 with sufficient accuracy. However, the temperature control via the heat flow takes place when the surface temperature of the substrate 2 can not be determined with sufficient accuracy.

The above explanations serve to explain the invention as a whole of the inventions, which further develop the prior art, at least by the following feature combinations each independently, wherein two, several or all of these feature combinations can also be combined, namely:

[0039] A method which is characterized in that the temperature control is influenced by the heat flow.

A device, characterized in that the temperature control is influenced by the heat flow.

A method or a device, characterized in that the temperature control has at least one control loop, in which the heat flow is the controlled variable, or that a changing heat flow results in a temperature setpoint correction.

A method or apparatus characterized in that the heat flow is detected by heat flow sensing means 20. A method or apparatus characterized in that the heat flow used in the temperature set point correction or in the temperature control is the waste heat flux 26 or the heating power 10.

A method or a device, which is characterized in that the cooling element 9 cooling channels 13, for passing a coolant, which dissipates the waste heat by a mass flow to the outside, wherein for determining the waste heat flow 26, a temperature difference of the coolant and its mass flow is determined by the cooling channels 13. A method or a device, which are characterized in that for controlling the heat flow, the heating power 10 of the heating element 5 is varied.

[0046] A method or a device which is characterized in that a variable heat flow resistance Rt3 is varied to regulate the heat flow.

A method or a device, which is characterized in that a mixture of gases with different thermal conductivity is fed to regulate the heat flow into a gap 8 between the process chamber ceiling 7 and the cooling element 9, the mixing ratio being varied.

[0048] A method or a device, which is characterized in that the desired value 29 of a heating controller 11 for controlling the heating power 10 has a surface temperature measured on the susceptor 4 or the substrate 2. is which set point 29 is changed by a setpoint presetting device 28 when the heat flow changes.

A method or a device characterized in that the desired value 29 is changed when the integral of a deviation of the heat flow from a predetermined standard value, which has been determined over time, has changed by a predetermined amount.

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 in order to undertake divisional applications based on these claims. The invention specified in each claim may additionally have one or more of the features described in the preceding description, in particular with reference numerals and / or given in the reference numerals. The invention also relates to design forms in which individual of the features mentioned in the above description are not realized, in particular insofar as they are recognizable dispensable for the respective purpose or can be replaced by other technically equivalent means. List of reference numbers

1 process chamber 25 correction variable

 2 substrate 26 waste heat flow, heat dissipation

3 substrate holder 27 throttle valve

 4 susceptor 28 setpoint presetting device

5 heating element, heating 29 setpoint

 6 susceptor temperature

 6 'substrate temperature

 7 process chamber ceiling

 8 gap Rtl heat flow resistance

9 Gas outlet plate Rt2 Heat flow resistance

9 'cooling element Rt3 heat flow resistance

10 heating power

 11 heating reg

 12 temperature reading

 13 cooling channel

 14 inlet

 15 process

 16 thermometers

 17 bag

 18 gas gap

 19 cover plate

 20 heat flow measuring device

 21 gas flow controller

 22 Nitrogen inflow

 23 Hydrogen inflow

 24 gas outlet opening

Claims

 claims Method for the thermal treatment of at least one substrate (2) in a process chamber (1) of a treatment device at a controlled temperature with a heat flow from a heating element (5) heating a susceptor (4) to which heating power (10) is supplied from the outside from the susceptor (4) heated substrate (2) and the process chamber (1), towards a cooling a process chamber ceiling (7) cooling element (9) from which a waste heat flow (26) is discharged to the outside, wherein the temperature control at least one control loop in which the heat flow is the controlled variable, characterized in that a variable heat flow resistance (Rt3) is varied to regulate the heat flow. Device for thermal treatment of at least one substrate (2) in a process chamber (1) of the device at a controlled temperature with a heating element (5), which by supplying a heating power (10) from the outside a heat flow from a susceptor heated by the heating element (5) (4) through the substrate heated by the susceptor (4) (2) and the process chamber (1) through to a cooling a process chamber ceiling cooling element (9), from which cooling element (9) a waste heat flow (26) is discharged to the outside, wherein the temperature control has at least one control loop, wherein the heat flow the controlled variable is characterized by a variable heat flow resistance (Rt3) to control the heat flow. 3. Method according to claim 1 or device according to claim 2, characterized in that the heat flow is detected by heat flow detection means (20). 4. The method or apparatus according to any one of the preceding claims, characterized in that the heat flow used in the temperature control of the waste heat flux (26) or the heating power (10). Method or device according to one of the preceding claims, characterized in that the cooling element (9) cooling channels (13), for passing a coolant, the senfluss through a mass senfluss the waste heat, wherein for determining the waste heat flow (26) a Temperature difference of the coolant and the mass flow through the cooling channels (13) is determined. Method or device according to one of the preceding claims, characterized in that for controlling the heat flow in a gap (8) between the process chamber ceiling (7) and the cooling element (9), a mixture of gases with different thermal conductivity is fed, wherein the mixing ratio is varied. Method or device for the thermal treatment of at least one substrate (2) in a process chamber (1) of the device at a controlled temperature with a heating element (5) which, by supplying a heating power (10) from the outside, a heat flow from one of the heating element (5) heated susceptor (4) by the susceptor (4) heated substrate (2) and the process chamber (1) through to a process chamber ceiling cooling cooling element (9) generates from which cooling element (9) a waste heat flow (26) to the outside wherein a control circuit regulates an actual temperature to a desired temperature and wherein means are provided to determine a heat flow, characterized in that a change in the heat flow has a correction of a temperature setpoint result. 8. A method or apparatus according to claim 7, characterized in that the heat flow used in the temperature setpoint correction of the waste heat flow (26) or the heating power (10). Method or device for the thermal treatment of at least one substrate (2) in a process chamber (1) of the device at a controlled temperature with a heating element (5) which, by supplying a heating power (10) from the outside, a heat flow from one of the heating element (5) heated susceptor (4) by the susceptor (4) heated substrate (2) and the process chamber (1) through to a process chamber ceiling cooling cooling element (9) generated by which cooling element (9) a waste heat flow (26) is discharged to the outside, wherein the temperature control has at least one control loop, wherein the heat flow is the controlled variable, characterized in that the heat flow used in the temperature control of the waste heat flow (26) or the heating power (10) is. A method or apparatus according to claim 9, characterized in that for controlling the heat flow, the heating power (10) of the heating element (5) is varied. Method or device according to one of the preceding claims, in particular according to claim 10, characterized in that the desired value (29) of a heating controller (11) for controlling the heating power (10) is a surface temperature measured on the susceptor (4) or the substrate (2), which set value (29) is changed by a target value setting means (28) when the heat flow changes. 12. The method according to claim 11, characterized in that the desired value (29) is changed when the integral over time integral of a deviation of the heat flow has changed from a predetermined standard value by a predetermined amount. 13. A device or method characterized by one or more of the characterizing features of one of the preceding claims.