DE102010009794A1 - Coating heated substrates in a continuous vacuum coating systems, comprises moving substrate in transport direction continuously through functional process chamber, in which coating particle stream is produced by using the coating sources - Google Patents

Abstract

The method comprises moving a substrate (9) in a transport direction (11) continuously through a functional process chamber (8), in which a coating particle stream is produced by using the coating sources (22) in the process chamber, coating the substrate in the process chamber by using the coating particle stream, past guiding the substrate inside the process chamber to two heaters (10), where the temperature of the substrates is controlled in the transport direction after the heater using a cascade control, which consists of a guidance control and a sequence control. The method comprises moving a substrate (9) in a transport direction (11) continuously through a functional process chamber (8), in which a coating particle stream is produced by using the coating sources (22) in the process chamber, coating the substrate in the process chamber by using the coating particle stream, past guiding the substrate inside the process chamber to two heaters (10), where the temperature of the substrates is controlled in the transport direction after the heater using a cascade control, which consists of a guidance control and a sequence control, where the substrate is controlled as a controlled system of the guidance control and the heater is controlled as a controlled system of sequence control. The temperature of the heater over the sequence control is controlled with the temperature of the respective heater as a control parameter, an respective energy supply to the respective heater as regulating variable, a respective target temperature as respective guidance parameter and a respective control deviation as difference of the respective guidance parameter of the sequence control and the respective control parameter of the sequence control. The substrate temperature over the guidance control is controlled with the substrate temperature as control parameter, a target substrate temperature as guidance parameter, a regulating variable controlling the respective control deviation of the sequence control and a control deviation as difference of guidance parameter of the guidance control and the control parameter of the guidance control. The respective target temperature is determined from the respective guidance parameter weighted with the regulating variable of the sequence control, as guidance parameter of the sequence control, where the respective guidance parameter corresponds to the respective basic adjustment of the heater temperature without guidance control. The weighting takes place by multiplication. The control deviation of the guidance control is compared with an adjustable maximum value and so long the control deviation of the guidance control exceeds the maximum value, which is weighted with a fixed value independent of the regulating variable of the sequence control. The respective guidance parameter is neutrally weighted i.e. is selected equal to the respective target temperature. The selection of the weighting takes place in dependent of an adjustable release signal. An independent claim is included for an arrangement for coating heated substrates in a continuous vacuum coating systems.

Description

The invention relates to a method for coating heated substrates in continuous vacuum coating systems, in which a substrate is moved continuously in a transport direction through a functional process chamber. In this case, a coating particle stream is generated by means of coating sources in the process chamber, by means of which the substrate is coated in this process chamber.

The invention also relates to an arrangement for coating heated substrates in continuous vacuum coating systems, comprising a functional process chamber, a transport device for the continuous transport of a substrate in a transport direction within the process chamber, and coating sources in the process chamber.

The coating sources given here can be designed differently. Thus, these may be formed as thermal evaporator, in which the coating particle stream is a vapor. Such thermal evaporators can be designed as pure steam crucibles in which the material to be evaporated is heated by various types of heating, such as direct heating or electron beam heating, so that a vapor phase is created in the vacuum of the process chamber.

However, the coating sources can also be called sputtering devices in the form of sputtering sources, also called magnetrons. In these cases, the magnetron is always connected as a cathode. In these coating sources, a plasma is generated primarily of the process gas, which ensures that the target material is atomized and this atomized material can be deposited as a coating particle stream on the substrate. A magnetron comprises a target of a material to be sputtered and a magnet system by means of which a magnetic field penetrating the target is generated.

The coating itself can be non-reactive, with the material dissolved out of the target or crucible depositing unchanged on the substrate. However, the coating can also take place in a reactive manner, with a second material, as a rule this is a reactive gas, being conducted into the process chamber, which then reacts with the coating particle stream of the target material, for example oxidized upon addition of oxygen. The so chemically altered material is deposited on the substrate. In a reactive coating with a magnetron, the reactive gas is ionized in the plasma and reacts with the atomized target material.

Partly reactive processes are also possible in which partially reactively modified material and unaltered material or substoichiometrically changed material are deposited.

The invention can be used for all possible types of coatings. Here, it is not the type of coating that is important, but rather the fact that each coating source in the above-mentioned o. Understanding represents a heat source that generates a disturbance, as will be explained in more detail below.

It is known to coat longitudinally extended substrates, such as band-shaped substrates, or plate-shaped substrates, which are arranged one behind the other in a longitudinal extension, in so-called continuous vacuum coating systems. The substrates are moved in a transport direction, which lies in the longitudinal extent of the substrates, through the vacuum coating system. This vacuum coating system also has a plurality of functional chambers in a longitudinal extent which lies in the transport direction. For example, the vacuum coating systems are designed as 3-chamber systems or as 5-chamber systems.

• – einer ersten funktionalen Kammer, nämlich der Eingangsschleuse, die auch eine physische Anlagenkammer darstellt,
• – einer zweiten funktionalen Kammer, bestehend häufig aus mehreren physischen Anlagenkammern, nämlich
• • einer ersten Transferkammer (in einer physischen Anlagenkammer),
• • einer Prozesskammer (zumeist in mehreren physischen Anlagenkammern) und
• • einer zweiten Transferkammer (in einer physischen Anlagenkammer), und
• – einer dritten (funktionalen) Kammer, nämlich der Ausgangsschleuse die wiederum eine physische Anlagenkammer darstellt.

A 3-chamber system consists of

• A first functional chamber, namely the entrance lock, which also constitutes a physical installation chamber,
• - a second functional chamber, often consisting of several physical enclosures, namely
• A first transfer chamber (in a physical plant chamber),
• • a process chamber (usually in several physical enclosures) and
• • a second transfer chamber (in a physical investment room), and
• - a third (functional) chamber, namely the exit lock, which in turn constitutes a physical installation chamber.

• – einer ersten funktionalen Kammer, nämlich der Eingangsschleuse, die auch eine physische Anlagenkammer darstellt,
• – einer zweiten funktionalen Kammer, nämlich einer ersten Pufferkammer, die auch eine physische Anlagenkammer darstellt,
• – einer dritten funktionalen Kammer, bestehend aus mehreren physischen Anlagenkammern, nämlich
• • einer ersten Transferkammer (in einer physischen Anlagenkammer),
• • einer Prozesskammer (zumeist in mehreren physischen Anlagenkammern) und
• • einer zweiten Transferkammer (in einer physischen Anlagenkammer),
• – einer vierten funktionalen Kammer, nämlich einer zweiten Pufferkammer, die auch eine physische Anlagenkammer darstellt, und
• – einer fünften (funktionalen) Kammer, nämlich der Ausgangsschleuse die wiederum eine physische Anlagenkammer darstellt.

A 5-chamber system consists of

• A first functional chamber, namely the entrance lock, which also constitutes a physical installation chamber,
• A second functional chamber, namely a first buffer chamber, which also constitutes a physical plant chamber,
• - a third functional chamber, consisting of several physical enclosures, namely
• A first transfer chamber (in a physical plant chamber),
• • a process chamber (usually in several physical enclosures) and
• A second transfer chamber (in a physical plant chamber),
• A fourth functional chamber, namely a second buffer chamber, which also constitutes a physical plant chamber, and
• - a fifth (functional) chamber, namely the exit lock, which in turn constitutes a physical installation chamber.

The invention now relates to a design of the process chamber in which the coating of the substrate takes place.

For various coating tasks, for example in the production of photovoltaic layers, it is necessary to keep the substrate at a certain temperature. Although it has always been important in the past that the substrate temperature does not exceed a certain amount, that is superheated, for which measures for substrate cooling were taken. However, it is not known in the prior art, substrates in the above-described form in the process chamber of continuous vacuum deposition systems to a temperature, in particular to temperatures of the order of 400 ° C to heat and maintain at this temperature.

Heating devices are known in continuous vacuum coating systems that adjust a temperature behavior of the substrates. In particular, they ensure targeted heating or targeted cooling (tempering) after vacuum treatment processes.

Thus, in the case of a coating with a heated substrate in the transport direction in front of the process chamber, a temperature of about 200 ° C. is set by preheating on the substrate. It is known to arrange several heaters or heater groups above or below the substrate transport system in the transport direction one behind the other. Each of these heaters or heater groups are provided with their own control circuit for controlling the heater temperature. Each heater or each heater group can be controlled so that they emit a constant heat radiation.

Such a control of conventional type is in 1 shown. The essential part is the controlled system 1 , In this context, the term "controlled system" generally refers to the physical unit, which is acted on by means of a manipulated variable and thus influences a parameter of this physical unit. In this case, this is a heater acted upon by the power supply, thereby changing its temperature, as shown below. In the scheme after 1 represents the controlled system 1 the heater or an interconnection of several heaters. On this heater affects a disturbance z. This can be, for example, a different heat absorption by the substrate, which is to be heated by heaters.

The controlled variable x, ie the variable to be controlled, in this case represents the temperature of the heater. This is measured and in the control loop 2 such that it is compared with a reference variable w, ie the setpoint size to be maintained. This gives the control loop 2 a control deviation x _w , ie a difference between controlled variable x and command variable w. By means of this control deviation, the controller provides 3 the manipulated variable y, in this case the energy supply to the heater, a.

By this regulation, although the temperature of the heater and thus the heat radiation to the substrate can be kept constant. However, the temperature of the substrate is only adjusted and not regulated. Since the heating takes place before the actual process chamber, beyond the substrate remains left after preheating temperature side itself, that is, any further heating or cooling processes remain out of consideration.

In addition, each heater is kept constant at a radiation intensity or temperature and thereafter by the control. Thus it is only possible to drive a certain "recipe", d. H. certain temperature ratios of the heaters to each other can not be changed dynamically.

In the DE 19907497 C2 is a cascade control of several heaters known, wherein the measurement of the temperature is carried out as a controlled variable by means of a pyrometer. Here, the heaters are controlled so that the same temperature as possible over the substrate surface is achieved. Temperature effects caused by any treatment steps are not taken into account here.

In the DE 25 01 895 B2 is an inline system described in which a steel belt is driven continuously. In this case, the steel strip is heated by induction. A temperature adjustment takes place via the regulation of the voltage in the coils, which serve the heating.

Out Töpfer, H. and Besch, P .: Fundamentals of Automation Technology, Berlin 1989, p. 292 is a cascade control known. Such a cascade control is in 2 shown. In such a cascade control is the controlled system 1 divided. In the example described in the reference, the temperature of the liquid should be controlled in a stirred tank. The stirred tank is heated via a water bath. The water of the water bath is heated via a heat exchanger whose energy supply in the primary circuit is adjustable and serves as a manipulated variable. In this case, the controlled system 1 in a first part of the rule 4 , which includes the water bath, and a second sub-rule 5 , which divided the stirred tank divided. Accordingly, by a first controller 6 the first part of the route 4 , ie, the energy supply to the primary circuit due to the control deviation x _w1 , which is determined from the temperature of the water bath as controlled variable x ₁ and set point W _{1 of} the water bath temperature regulated. The peculiarity consists in the fact that the desired value W ₁ itself is the result of a control process. In fact, this setpoint W ₁ becomes the manipulated variable y _{1 of} a second controller 7 from the control deviation x _{w2 determined} from the actual temperature of the liquid in the stirred tank as the second control variable x ₂ and setpoint of this temperature as the second command variable w ₂ .

Such a cascade control thus assumes that a total controlled system 1 in a first part of the rule 4 , which listened to a sequence loop, which corresponds to the above-mentioned usual control loop, and in a second part of the control loop 5 , which belongs to a master control loop is divided. The manipulated variable y _{1 of} the controller is used 7 of the master control loop as a reference variable w ₁ for the follower loop.

The invention is now based on the object of enabling a coating of substrates in continuous vacuum coating systems, in which the substrate temperature is influenced within the functional process chamber.

The object is achieved according to a method according to the invention in that the substrate is guided past at least one heater within the process chamber, wherein the substrate temperature, d. H. the temperature of the substrate in the direction of transport after the heater, by means of a cascade control, consisting of a guidance and a follow-up control, in which the substrate is controlled as a controlled system of the command control and the heater as a controlled system of the sequence control, referring to the definition of the controlled system introduced at the outset becomes. Thus, it is possible to perform coating processes with a heated substrate, wherein the temperature of the substrate within the functional process chamber which is indeed influenced by at least the disturbance of the heat input via the coating sources is not left uncontrolled. In particular, this makes it possible to heat substrates within the process chamber, without the result that an inadmissible thermal stress of the substrate can occur due to the thermal disturbances.

In one embodiment variant of the method according to the invention, it is provided that, on the one hand, the temperature (T _ist1 ) of the heater is regulated via the follow-up control. This follow-up control is characterized in that it is the temperature (T _ist1 ) of the heater as a controlled variable, a power supply (Y ₁ ) to the heater as a control variable, a setpoint temperature (T set _internally ) as a reference variable and a control deviation (ΔT _{soll-ist Heizer} ) as a difference from the reference variable (T _internally ) of the follow-up control and controlled variable (T _ist1 ) of the follow-up control. On the other hand, the substrate temperature (T _{is substrate} ) is controlled by the lead control. These guide control being characterized in that they substrate temperature (T _{is the substrate)} as a control variable, a desired substrate temperature (T _{soll substrate)} as a reference variable, a control deviation (.DELTA.T _{target-heater)} of the sequence control controlling the manipulated variable (Y _u), and a control deviation (ΔT _{should-is substrate} ) as the difference between the reference variable (T _{soll substrate} ) of the command control and controlled variable (T _{is substrate} ) of the command control. Reference is made here to the terms known from the above-described prior art for defining the invention. This also applies to the arrangement described below.

In a further embodiment of the method according to the invention, it is provided that the substrate is guided past at least two heaters within the process chamber, wherein the substrate temperature, ie. H. the temperature of the substrate in the transport direction after the last heater, by means of a cascade control, consisting of a management and a follow-up control, in which the substrate is controlled as a controlled system of the control and the heaters control systems of the sequence control. This means that each heater is provided with its own follower loop, whereas each follower loop is influenced by one and the same guide control in its respective reference variable. Thus, it becomes possible to eliminate, via the heaters, the thermal disturbances which influence the temperature of the substrate in their thermal effect on the substrate. For example, an arrangement can be selected in which a coating source, for. B. a magnetron is arranged between two heaters.

In a further embodiment of the method according to the invention, which can be applied both to a heater and to the arrangement of two or more heaters, it is provided that the temperatures (T _ist1 , T _ist2 ... T _istn ) of the heater or _heaters respectively a sequence control with in each case the temperature (T _ist1 , T _ist2 ... T _istn ) of the respective heater as controlled variable, of a respective energy supply (Y ₁ , Y ₂ ... Y _n ) to the respective heater as manipulated variable, of a respective setpoint temperature ( T _{soll1 internally} , T _{soll2 internally} ... T _{solln internally} ) as a reference variable and a respective control deviation (ΔT _{soll-ist Heater1} , ΔT _{should-is heater2} ... ΔT _{should-is heater} ) as a difference from the respective _reference variable (T _{set1 internal} , T _{set2 internal} ... T _{set internal} ) of the following control and the respective control variable (T _ist1 , T _ist2 . .. T _istn ) of the _follow-up regulation is regulated. In this case, the substrate temperature (T _{is substrate} ) via the guide control with the substrate temperature (T _{is substrate} ) as a controlled variable, a target substrate _temperature (T _substrate ) as a _{reference variable} , the respective control deviations (.DELTA.T _{should-is Heizer1} , _{.DELTA.T is-is Heizer2} ... ΔT _{is-is heaters} ) of the _{follow-up controls} controlling variable (Y _ü ) and the control deviation (.DELTA.T _{should-is substrate} ) as the difference between the reference variable (T _substrate ) of the control and controlled variable (T _{is substrate} ) of the control loop regulated.

Certain heat profiles can also be set via the substrate, with the substrate, for example, passing through a particularly fast or particularly slow heating process, where certain temperatures must be maintained at certain locations within the process chamber, or the like. This can be realized with an embodiment of the method according to the invention in that the respective setpoint temperature (T _{soll1 internally} , T _{soll2 internally} ... T _{solln internally} ) as a _{reference variable of the follow-up control} from a respective _reference variable weighted with the manipulated variable (Y _u ) of the sequence control ( T _soll1 , T _soll2 ... T _solln ), which corresponds to a respective basic setting of the heater temperature without a master control.

It can be provided that the weighting is done by multiplication. Thus, the respective setpoint temperature (T _{setpoint 1} , T _{setpoint 2} ... T _setpoint ) predetermined for the heater is reduced or increased with the value of the manipulated variable (Y _u ).

In a further embodiment of the method according to the invention, it is provided that the control deviation (.DELTA.T _{should-is substrate} ) of the control is compared with an adjustable maximum value (max .DELTA.T _{is-is substrate} ) and as long as the control deviation (.DELTA.T _{is-is substrate} ) of the control Maximum value (max ΔT _{should-is substrate} ), the respective _reference variable (T _soll1 , T _soll2 ... T _solln ) is _weighted independently of the manipulated variable (Y _ü ) of the follow-up control with a fixed value. A special configuration consists in the fact that the respective _reference variable (T _soll1 , T _soll2 ... T _solln ) is weighted neutral, irrespective of the manipulated variable (Y _ü ), ie equal to the respective setpoint temperature (T _{soll1 intern} , T _{soll2 intern} . .. T _{solln internally} ) is selected. This ensures that the control of certain process sections is, so to speak, eliminated or rendered ineffective. This can be the case, in particular in heating processes, in a newly started process. By this measure, the heaters can be set (either by specifying their respective setpoints (T _soll1 , T _soll2 ... T _solln ) and / or by increasing the respective _reference variables (T _{soll1 intern} , T _{soll2 intern} ... T _{solln internally} ) by the manipulated variable (Y _ü )) that a retracted process status can be reached very quickly.

The process of weighting independent of the master control can also be turned on or off by selecting the weighting in response to an adjustable enable signal.

The arrangement-side solution of the task is that within the process chamber at least one heater which can be heated by the substrate is arranged. In the transport direction after the heater, a substrate temperature measuring sensor is arranged. A master controller, which is connected to the substrate as a controlled system and the sensor to a master control loop, and a slave controller, which is connected together with the heater as a controlled system to a follower loop, are both part of a cascade control such that the master control circuit sets the reference variable of the sequence control circuit. Due to the features of this arrangement, it is even possible, in addition to the coating sources, which introduce an uncontrolled heat input into the substrate, still bring in heaters. Thus, the setting of substrate temperatures above 400 ° C is possible, which significantly increases the range of coating application. The invention may include individual heaters as well as groups of heaters, which consist of individual heaters and are considered here as a heater.

In one embodiment of the invention, it is provided that a first measuring point measuring the actual temperature (T _ist1 ) of the heater is connected to a control variable input of a first comparator whose reference variable input via a weighting point with a setpoint generator for specifying the Heizersolltemperatur (T _soll1 ) and its control deviation _output connected to a power supply to the heater subsequent slave controller. A second measuring point which measures the actual temperature (T _{is substrate} ) of the substrate is connected to a controlled variable input of a second comparator whose command variable input _is connected to a setpoint generator for specifying the substrate target temperature (T _{soll substrate} ) and whose control deviation output is connected to a master controller adjusting the weighting of the weighting point.

The invention also encompasses the arrangement of a plurality of heaters, which are arranged, for example, next to one another or behind one another, possibly between a plurality of coating sources, in that at least two heaters which can be heated by the substrate are arranged within the process chamber. In the transport direction is after the last heater a substrate temperature measuring sensor arranged. A master controller, which is interconnected with the substrate as a controlled system and the sensor to a master control loop, and one slave controller, which are connected together with the respective heaters as controlled systems, each a follower loop, are part of a cascade control such that the master control loop, the reference variable of the sequence control circuits pretends.

In a further embodiment, it is provided that each sequence control loop is assigned a weighting point, which is connected to a setpoint generator for specifying the respective desired heater temperature (T _soll1 , T _soll2 ... T _solln ). This makes it possible to assign each setter to its setpoint temperature, ie to set different temperature profiles. It is of course possible to set temperature profile pattern with several heaters, either manually or via appropriate adjustment.

The master control loop can be taken out of action as needed, for example, in processes that would not necessarily slow down with the guide control by the master control loop is provided with a comparator whose one comparison input with the output of the second comparator, ie the output of the control deviation Guiding control loop, and the second comparison input _is connected to a maximum value (max ΔT _{is-is substrate} ) for the control deviation of the command control predetermining setpoint generator. The digital output of the comparator is connected to a control input of a switch, the switch connects the input of the weighting point either to the output of the master controller or to a fixed value generator.

The temporary switching off of the master control loop can be controlled by an AND gate connected between the comparator output and the control input of the switch, wherein an AND input to the comparator output and the other AND input is connected to an enable signal generating means.

In a further embodiment of the invention, the possibility is opened up that the command control and the manipulated variable of the command control means are implemented in a processor. The construction according to the invention and the method allow for such an implementation, whereby the production costs decrease considerably.

Another possibility of the embodiment of the arrangement according to the invention is that the weighting point is designed as a multiplier.

As already explained above, the invention can refer to individual heaters or to groups of individual heaters, which are understood here as heaters. However, it is also possible to apply the invention to individual heaters within a heater group, in which case the individual heaters of the heater group are understood as heaters in the sense of the invention. It is also possible to use the invention for setting a temperature profile along the transport direction by the heaters are arranged one behind the other in the transport direction, or transversely to the transport direction by the heaters are arranged side by side transversely to the transport direction. Of course, it is possible to set both a longitudinal and a transverse distribution by controlling an entire heater field, consisting of transversely and longitudinally arranged individual heaters according to the invention.

For non-contact measurement of the substrate temperature, which is useful in particular as a result of the substrate movement, it is provided in one embodiment of the invention that the sensor measuring the substrate temperature is designed as a pyrometer.

The invention will be explained in more detail with reference to an embodiment. In the accompanying drawings shows

1 a standard control loop according to the prior art,

2 a control circuit of a cascade control according to the prior art,

3 an inventive arrangement with a heater,

4 an inventive arrangement with several heaters

5 an inventive arrangement with several heaters and a fixed value control,

6 an inventive arrangement with several heaters and a switchable fixed value control,

7 an arrangement according to the invention with a plurality of heaters and a disturbance-dependent fixed value control,

8th an embodiment of the inventive arrangement with pyrometer control circuits

9 an arrangement with several pyrometer control circuits,

10 a schematic representation of the position of heaters of the arrangement according to the invention.

As in 3 is shown within a process chamber 8th at least one the substrate 9 heatable heater 10 arranged. In transport direction 11 after the heater 10 is a first measuring point measuring the substrate temperature 12 arranged.

A leader 13 , is with the substrate 9 as a second partial control section 5 and the first measuring point 12 connected to a master control loop, and a slave controller 14 , the first controller 6 in 2 matches, is with the heater 10 as the first partial control section 4 interconnected to a sequence loop.

The master control loop gives the command variable T set _{internally of} the sequence control loop, here as the heating control loop 15 designated before.

In detail, one is the actual temperature T _{ist1 of} the heater 10 measuring first measuring point 12 with a controlled variable input of a first comparator 16 whose reference variable input is via a weighting point 17 with a first setpoint generator 18 for specifying the heater target temperature T _soll1 and its control deviation _output with an energy supply to the heater 10 secondary sequencer 14 connected is. An actual temperature T _{is the substrate of} the substrate 9 measuring second measuring point 19 is with a controlled variable input of a second comparator 20 whose reference variable input is connected to a second setpoint generator 21 for specifying the substrate target temperature T _{is substrate} and its deviation output with the weighting of the weighting point 17 adjusting master controller 13 connected is.

In 4 is the arrangement of several heaters 10 represented, for example, side by side or one behind the other, possibly between several coating sources 22 , within the process chamber 8th and in several heating control loops 15 (Heating RK1, heating RK2, ... heating RKn) are arranged. In transport direction 11 is after the last of the heater 10 the second measuring point measuring the substrate temperature 19 arranged. The weighting points 17 are each heating loop 15 (Heating RK1, heating RK2, ... heating RKn) assigned. These are with a setpoint generator 18 for specifying the respective Heizersolltemperatur T _soll1 , T _soll2 ... T _solln connected. Thus, it becomes possible for each of the heaters 10 its target temperature T _soll1 , T _soll2 ... T _solln assign, so set different temperature profiles.

The temperatures T _ist1 , T _ist2 ... T _istn the heater 10 are in this arrangement via a respective sequence control, each with the temperature T _ist1 , T _ist2 ... T _istn the respective heater 10 as a control variable, a respective energy supply Y ₁ , Y ₂ ... Y _n to the respective heater 10 as a manipulated variable, a respective set temperature T _{set1 internally} T _{set2 internally} ... T _{solln internally} as a reference variable and a respective control error .DELTA.T _{target is Heizer1,} .DELTA.T _{target is Heizer2} ... .DELTA.T _{target is heaters} as the difference between the respective command variable T _{set1 internal,} T ... T _{set2 internally solln} the sequence control and the respective control variable T _{IST1, IST2} T ... T _istn the sequence control _internally regulated. In this case, the substrate temperature T _{is substrate} via the guide control with the substrate temperature T _{is substrate} as a controlled variable, a target substrate _temperature T _{soll substrate} as a _{reference variable} , the respective control deviations ΔT _{soll-ist Heizer1} , ΔT _{soll-ist Heizer2} ... ΔT _{soll- is heater of} the follow-up controls controlling variable Y _ü and the control deviation .DELTA.T _{should-is substrate} as a difference from the reference variable T _{should substrate of} the control and controlled variable T _is controlled _{substrate of} the control.

As in 5 shown, the master control loop can be taken as needed from its action. For this purpose, it is provided that the master control loop with a comparator 23 is provided, the first comparison input 24 with the output of the second comparator 20 , ie the output of the control deviation .DELTA.T _{soll-is substrate} of the master control loop, and its second comparison input 25 with a maximum value max .DELTA.T _{soll-ist substrate} for the control deviation .DELTA.T _{soll-ist substrate} is connected to the master control preselected setpoint generator. The digital output 26 of the comparator 23 is with a control input of a changeover switch 27 connected, the switch 27 the entrance of the weighting point 17 either with the output of the master controller 13 or with a fixed value generator 28 combines.

In this embodiment, the control deviation .DELTA.T _{is-is substrate} of the closed-loop control _is compared with an adjustable maximum value max .DELTA.T _{soll-ist substrate} . As long as the control deviation .DELTA.T _{should-substrate of} the control is the maximum value max .DELTA.T _{soll-ist substrate} exceeds, so long as, for example, the substrate 9 is cold, the respective _reference variable T _soll1 , T _soll2 ... T _solln regardless of the manipulated variable Y _{ü of} the _sequence control weighted with a fixed value. An increase of the setpoint temperatures T _{soll1 internally} , T _{soll2 internally} ... T _{solln internally} compared to the set target temperatures T _soll1 , T _soll2 ... T _{solln can be} effected, for example, to heat up faster. A special design consists in the fact that the respective _reference variable T _soll1 , T _soll2 ... T _solln regardless of the manipulated variable Y _{ü of} the _sequence control is effective. It can also, as in 5 and 6 a neutral weighting is carried out, ie the _reference variables T _soll1 , T _soll2 ... T _solln become the value 1,0 weighted, with the weighting points 17 are trained as multipliers.

The temporary switching off of the master control loop can be controlled by switching between the comparator output 26 and the control input 29 the switch an AND gate 30 is switched, wherein the one AND input to the comparator output 26 and the other AND input with an enable signal generating means 31 connected is.

As in 7 illustrated, the shutdown of the master control loop can also by a second comparator 32 be controlled by this a signal to the AND gate 30 until the sum of all disturbance variables Z ₁ , Z ₂ ,... Z _{n has reached} a maximum value Z _max .

Below is the function of in 8th described inventive arrangement described. For non-contact measurement of the substrate temperature, which is useful in particular as a result of the substrate movement, it is provided that the second measuring point 19 is designed as a pyrometer.

The deviations of the target temperature T _{soll substrate} from the actual temperature T _{is substrate of} the substrate 9 that from the pyrometer 19 is measured by the higher-level PI controller in the pyrometer control loop 33 for controlling the internal heater setpoint temperatures of the heaters 10 Heater 1, ..., heater i, ..., heater n, used here as heater groups used. As long as the leader 13 acting higher-level PI controller 34 is active (enable), all internal heater setpoint temperatures T _{set1 internal} , T _{set2 internal} ... T _{set internally to} the assigned heater 10 calculated using the manipulated variable Y _ü . The associated heaters 10 change their temperature T _ist1 , T _ist2 ... T _istn and as a result the temperature changes T _{is substrate of} the substrate 9 , The manipulated variable Y _ü changes accordingly. The control process should lead to the predefined substrate temperature T _{ist substrate} in a timely manner given correct control loop parameters. If interference from additional heat sources or heat sinks from the process occurs, then the cascaded control loop will correct these disturbances in a timely manner.

In certain cases, the parent PI controller must 34 and thus the pyrometer control loop 33 not yet active. For this purpose, no release is granted and the heaters 10 are _regulated according to the setpoint temperatures T _soll1 , T _soll2 ... T _solln from the current heater recipe.

So that the pyrometer control loop 33 becomes active, also the starting temperature T _{is substrate of} the substrate 9 lie within a tolerance range specified by the operator. If the temperature is outside this range, for technological reasons, the cause must be clarified and eliminated, until then the pyrometer control loop 33 not active. However, this condition can be overridden by a proper choice of tolerance.

Below is the in 9 illustrated inventive arrangement described.

With this setup, there is a form of cascading PI controllers when a pyrometer control loop (master) issues a release of the successor pyrometer control loop (Slawe). The temperature of the substrate at the exit of the effective range of a pyrometer control loop is at the same time the input temperature into the range of action of the follower pyrometer control loop. The result of the work of the slave pyrometer control loop depends on the error of the master pyrometer control loop. For technological and safety reasons, however, this error may only be within certain limits, or a technologically and safety-related maximum / minimum permissible temperature of the substrate need not be exceeded or fallen below. As a necessary measure against impermissible disturbances of the temperature, this form of cascading is proposed here - the release by the master. It guarantees the technologically and safety-related required input temperature in the slave pyrometer control loop. A slave pyrometer control loop can only be active (ie, can change setpoint temperatures) if it receives clearance from the software / operator and the master. In addition, each higher-level PI controller in the maximum and minimum value of the manipulated variable Y _ü limited so that the actual and target temperatures of the substrate at the output of the respective pyrometer control loops smaller difference than the corresponding max. ΔT _substrate e should have, so that the pyrometer control loop can regulate.

The first pyrometer control loop gets a release from the server and / or from the software. This release may be technologically conditioned (heating the system up to working temperature, only then does a pyrometer control make sense) or when testing recipes in which the work of the pyrometer control loop is not desired.

At the in 8th and 9 described embodiment is the pyrometer control loop 33 implemented in a computer. The software used has the following characteristics:

a) Basic functions

• - The software evaluates the temperature T _{is substrate of} the substrate 9 from the pyrometers 19 out.
• - The absence of a substrate 9 in front of a pyrometer 19 shall be recognized by the software and no evaluation of temperatures from this pyrometer shall take place during this time. During this time, the software gives the higher-level PI controller 34 the last valid temperature value of the substrate.
• - The software guarantees at least one pyrometer control loop 33 and is due to a larger number of pyrometer control loops 33 modular expandable.

b) Functions for usability

• - Visualization of the control parameters as well as the state of the higher-level controller (active / inactive)
• - Configurability of the release ratios is possible for advanced users.
• - The software allows the operator to
• Turn off the control logic to avoid changes to the heater parameters in the appropriate C4 sections as necessary.
• - The manual change of control parameters as well as switching on and off of the higher-level PI controllers is logged.
• - For service purposes and for advanced service operators, the software allows direct access to the controller parameters of the respective higher level controller.
• - The parameters of the higher-level controllers are recorded in heater recipes.

As already explained above, the invention can be applied to individual heaters or to groups 35 from single heaters refer to here as heaters 10 be understood. In 10 Now different constellations are shown. It is possible, the invention to individual heaters within a heater group 35 apply, in which case the individual heaters of the heater group 35 as a heater 10 be understood within the meaning of the invention apply. It is also possible, the invention for setting a temperature profile along the transport direction 11 to use by the heaters 10 in the transport direction 11 are arranged one behind the other, or transversely to the transport direction 11 by the heaters 10 are arranged side by side transversely to the transport direction.

Of course, it is possible to adjust both a longitudinal and a transverse distribution by a whole heater field, consisting of transversely and longitudinally arranged heaters 10 is regulated according to the invention.

Each of the heaters, which are arranged side by side transversely to the transport direction (in 10 the middle and the lower illustration), must be part of a separate control operating on a separate track in the direction of transport. Only then is a transverse distribution of the temperature adjustable. Between such pyrometer control loops, however, there may be interaction, which are designed in the form of release signals.

LIST OF REFERENCE NUMBERS

1

controlled system

2

loop

3

regulator

4

first partial control section

5

second partial control section

6

first controller

7

second controller

8th

process chamber

9

substratum

10

stoker

11

transport direction

12

first measuring point (in the heating control loop)

13

master controller

14

slave controller

15

Heating control loop (follower loop)

16

first comparator (in the heating loop)

17

Weighting place

18

Setpoint generator

19

second measuring point, pyrometer

20

second comparator

21

second setpoint generator

22

coating source

23

comparator

24

first comparison input

25

second comparison input

26

comparator output

27

switch

28

Fixed value generator

29

control input

30

AND gate

31

enable signal

32

second comparator

33

Pyrometer control loop

34

higher-level PI controller

35

heater group

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19907497 C2 [0019]
• DE 2501895 B2 [0020]

Cited non-patent literature

• Töpfer, H. and Besch, P .: Fundamentals of Automation Technology , Berlin 1989, p. 292 [0021]

Claims (20)

A method of coating the heated substrates in the continuous vacuum coating systems in which a substrate is moved continuously in a transport direction by a functional process chamber in which a coating particle is produced by coating sources in the process chamber by means of which the substrate is coated in the process chamber, characterized in that the substrate is guided past at least one heater within the process chamber, wherein the substrate temperature, ie the temperature of the substrate in the transport direction after the heater, by means of a cascade control, consisting of a guidance and a follow-up control, in which the substrate as the controlled system Guiding control and the heater is controlled as a controlled system of the sequence control. A method according to claim 1, characterized in that - the temperature (T _is ) of the heater on the follow-up control with the temperature (T _ist1 ) of the heater as a control variable, an energy supply (Y ₁ ) to the heater as a manipulated variable, a set temperature (T _{soll internally} ) as a reference variable and a control deviation (.DELTA.T _{is-is heater} ) as a difference from the reference variable (T _{is internal} ) of the sequence control and controlled variable (T _ist1 ) of the follow-up control is controlled, and - the substrate temperature (T _{is substrate} ) via the guide control with the Substrate temperature (T _{is substrate} ) as a controlled variable, a target substrate temperature (T _{soll substrate} ) as a reference variable, a control deviation (.DELTA.T _{is-is heater} ) of the follow-up control controlling variable (Y _ü ) and a control deviation (.DELTA.T _{should-is substrate} ) as difference between the reference variable (T _{soll substrate)} of the guide and control controlled variable (T _{is the substrate)} of the guide rules is regulated. A method according to claim 1 or 2, characterized in that the substrate is guided within the process chamber past at least two heaters, wherein the substrate temperature, d. H. the temperature of the substrate in the transport direction after the last heater, by means of a cascade control, consisting of a management and a follow-up control, in which the substrate is controlled as a controlled system of the control and the heaters control systems of the sequence control. A method according to claim 3, characterized in that - the temperatures (T _ist1 , T _ist2 ... T _istn ) are the heaters via a respective _{sequence control} with the respective temperature (T _ist1 , T _ist2 ... T _istn ) of the respective heater as Controlled variable, a respective energy supply (Y ₁ , Y ₂ ... Y _n ) to the respective heater as a manipulated variable, a respective setpoint temperature (T _{soll1 internally} , T _{soll2 internally} ... T _{solln internally} ) as a _reference variable and a respective control deviation (.DELTA.T _{target is Heizer1,} .DELTA.T _{target is Heizer2} ... .DELTA.T _{target is heaters)} as the difference (from the respective reference variable T _{set1 internally} T _{set2 internally} ... T _{internal) solln} the sequence control and the respective control variable (T _IST1, T _act2 ... T _istn) of the sequence control is regulated, and - the substrate temperature (T _{is the substrate)} over the guide arrangement with the substrate temperature (T _{is the substrate)} as a control variable, (a target substrate temperature T _{set substrate)} as the reference variable, the jewe iligen control deviations (.DELTA.T _{target is Heizer1,} .DELTA.T _{target is Heizer2} ... .DELTA.T _{target is heaters)} of the sequence rules controlling the manipulated variable (Y _u) and the system deviation (.DELTA.T _{target-substrate)} as the difference between reference variable (T _{soll substrate)} the guiding control and controlled variable (T _{is substrate} ) of the guiding control is regulated. A method according to any one of claims 1 to 4, characterized in that the respective target temperature (T _{set1 internally} T _{set2 internally} ... T _{solln internal)} weighted as a reference variable of the sequence control from one with the manipulated variable (Y _u) of the sequence control respective reference variable ( T _soll1 , T _soll2 ... T _solln ), which corresponds to a respective basic setting of the heater temperature without a master control. A method according to claim 5, characterized in that the weighting is done by multiplication. A method according to claim 5 or 6, characterized in that the control deviation (.DELTA.T _{should-is substrate} ) of the control loop with an adjustable maximum value (max .DELTA.T _{is-is substrate} ) is compared and as long as the control deviation (.DELTA.T _{is-substrate substrate} ) of the guide control Maximum value (max ΔT _{should-is substrate} ), the respective _reference variable (T _soll1 , T _soll2 ... T _solln ) is _weighted independently of the manipulated variable (Y _ü ) of the follow-up control with a fixed value. Method according to Claim 7, characterized in that the respective _reference variable (T _soll1 , T _soll2 ... T _solln ) is weighted neutrally, ie equal to the respective setpoint temperature (T _{soll1 internal} , T _{soll2 internal} ... T _{nominal internal} ). A method according to claim 7, characterized in that the selection of the weighting takes place in dependence on an adjustable enable signal. Arrangement for coating heated substrates in continuous vacuum coating systems, with a functional process chamber, a transport device for continuously transporting a substrate in a transport direction within the process chamber, and with coating sources in the process chamber, characterized in that within the process chamber at least one heater which heats the substrate is arranged, that in the transport direction after the heater a the Substrate temperature measuring sensor is arranged, that a master controller, which is interconnected with the substrate as a controlled system and the sensor to a master control loop, and a slave controller, which is connected to the heater as a controlled system to a sequence control circuit, both of which are part of a cascade control such that the master control loop specifies the reference variable of the sequence control loop. Arrangement according to Claim 10, characterized in that a first measuring point measuring the actual temperature (T _ist1 ) of the heater is connected to a control variable input of a first comparator, whose command variable input via a weighting point with a setpoint generator for specifying the desired heater temperature (T _soll1 ) and whose control deviation _output a subsequent control of the energy supply to the heater is connected, that the actual temperature (T _{is substrate} ) of the substrate measuring second measuring point is connected to a controlled variable input of a second comparator, the reference variable input with a setpoint generator for specifying the substrate target temperature (T _substrate ) and its control deviation output is connected to a weighting position adjusting master controller. Arrangement according to claim 10 or 11, characterized in that within the process chamber at least two heatable the substrate heaters are arranged, that in the transport direction after the last heater, a substrate temperature measuring sensor is arranged, that a guide controller, with the substrate as a controlled system and the Sensor is interconnected to a master control loop, and each a slave controller, which are interconnected with the respective heaters as controlled systems to each a follower loop, which are part of a cascade control such that the master control circuit sets the reference variable of the follower circuits. Arrangement according to claim 12, characterized in that each sequence control loop is assigned a weighting point, which is connected to a setpoint generator for specifying the respective desired heater temperature (T _soll1 , T _soll2 ... T _solln ). Arrangement according to one of claims 10 to 13, characterized in that the master control loop is provided with a comparator whose one comparison input with the output of the second comparator, ie the output of the control deviation of the control loop, and the second comparison input with a maximum value (max .DELTA.T _{should-is substrate} ) is connected to the control deviation of the default setpoint generator whose digital output is connected to a control input of a switch, the switch connects the input of the weighting point either to the output of the master controller or to a fixed value generator. Arrangement according to claim 14, characterized in that between the comparator output and the control input of the switch an AND gate is connected, wherein an AND input to the comparator output and the other AND input is connected to a release signal generating means. Arrangement according to one of claims 11 to 14, characterized in that the control means and the manipulated variable of the command control means are implemented in a processor. Arrangement according to one of claims 11 to 16, characterized in that the weighting point is designed as a multiplier. Arrangement according to one of claims 11 to 17, characterized in that the heaters are arranged one behind the other in the transport direction Arrangement according to one of claims 11 to 17, characterized in that the heaters are arranged transversely to the transport direction side by side. Arrangement according to one of claims 10 to 19, characterized in that the substrate temperature measuring sensor is designed as a pyrometer.

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