阅读说明：本技术 确定密闭腔室中衬底位置的方法和执行该方法的装置 (Method for determining position of substrate in closed chamber and apparatus for performing the same ) 是由 彭寿 迈克尔·哈尔 殷新建 傅干华 克里斯蒂安·克拉夫特 斯特凡·拉乌 巴斯蒂安·希普欣 于 2017-11-30 设计创作，主要内容包括：本发明涉及一种确定密闭腔室中衬底位置的方法和装置,其中,所述衬底通过传输系统在腔室内移动,所述传输系统至少包括一个旋转轴。提供了相邻于至少一个所述旋转轴的负载转换元件,其中所述负载转换元件检测作用在所述至少一个旋转轴上的负载并将其转换成电参数。当所述至少一个旋转轴上不存在衬底时,测量对应于电参数的第一值的第一输出信号。当输出信号与第一输出信号相差至少预定量时,监测输出信号并检测所述至少一个旋转轴上是否存在衬底。(The invention relates to a method and an apparatus for determining the position of a substrate in a closed chamber, wherein the substrate is moved in the chamber by a transport system comprising at least one rotation axis. A load converting element is provided adjacent to at least one of the rotating shafts, wherein the load converting element detects the load acting on the at least one rotating shaft and converts it into an electrical parameter. A first output signal corresponding to a first value of an electrical parameter is measured when no substrate is present on the at least one rotational axis. When the output signal differs from the first output signal by at least a predetermined amount, the output signal is monitored and the presence or absence of a substrate on the at least one axis of rotation is detected.)

1. A method of determining the position of a substrate in a closed chamber, wherein the substrate is moved within the chamber by a transport system comprising at least one rotating shaft, the method comprising the steps of:

providing a load transferring element adjacent to at least one of said rotating shafts, wherein said load transferring element is adapted to detect a load acting on said at least one rotating shaft and to transfer it into an electrical parameter corresponding to said load,

measuring a first output signal corresponding to a first value of the electrical parameter of the load converting element in the absence of a substrate on the at least one rotational axis,

monitoring an output signal corresponding to a value of the electrical parameter of the load converting element, an

Detecting the presence of a substrate on the at least one rotational axis when the output signal of the load conversion element differs from the first output signal by at least a predetermined amount.

2. The method of claim 1, wherein if the presence of the substrate is not detected at a first point in time, damage or loss of the substrate or a disturbance of the motion of the substrate is detected, for which purpose the presence of the substrate on the rotation axis is predicted by inference using a known position of the substrate and characteristics of a movement system moving the substrate from the known position to the rotation axis.

3. The method of claim 1 or 2, further comprising: obtaining a first characteristic of the output signal for calibration by monitoring the output signal while a known calibration substrate is moved entirely on the rotation axis, wherein the first characteristic comprises a first gradient corresponding to the calibration substrate reaching the rotation axis, a second gradient corresponding to the substrate leaving, and a maximum.

4. The method of claim 3, further comprising at least one of:

detecting damage of the substrate at a leading edge thereof if a first gradient of a second characteristic of the output signal obtained by monitoring the output signal is different from a first gradient of the first characteristic when the substrate is completely moved on the rotation axis,

detecting damage of the substrate at its trailing edge if a second gradient of a second characteristic of the output signal obtained by monitoring the output signal when the substrate is moved completely on the rotation axis is different from a second gradient of the first characteristic,

detecting damage of the substrate on a side edge or a first surface if a maximum value of a second characteristic of the output signal obtained by monitoring the output signal when the substrate is completely moved on the rotation axis is smaller than a maximum value of the first characteristic, or

Determining a thickness of a layer deposited on the substrate within the chamber by monitoring a maximum of a second characteristic of the output signal obtained when the substrate is moved fully on the rotational axis.

5. The method of any one of the preceding claims,

a plurality of load converting elements are disposed adjacent to the plurality of rotating shafts, wherein each load converting element is adapted to detect a load acting on one of the rotating shafts,

measuring the output signal of each load conversion element at one and the same point in time in the presence of a substrate on at least some of said rotation axes, an

Determining a weight or size of the substrate from the measured output signal.

6. A method according to any of the preceding claims, wherein the load converting element is arranged within a radial bearing holding the rotating shaft and wear of the bearing is detected if the output signal shows linear or super-linear drift over a period of time, including a large number of substrate channels on the rotating shaft.

7. The method according to any of the preceding claims, wherein the load converting element is a piezoelectric element or a strain gauge.

8. A method according to any one of the preceding claims, wherein the transport system comprises a plurality of rotation axes and is adapted to move substrates directly on the rotation axes, or the transport system comprises a belt supported by the at least one rotation axis and is adapted to move substrates on the belt.

9. Method according to any one of the preceding claims, wherein the closed chamber is a vacuum or atmospheric pressure chamber adapted to provide a reactive, corrosive or misty atmosphere and/or adapted to be heated to a temperature above 300 ℃, in particular above 500 ℃.

10. The method of any of the preceding claims, wherein the closed chamber is a closed space sublimation chamber and a closed space sublimation process is performed while the substrate is within the closed chamber.

11. An apparatus to perform the method of claim 1, the apparatus comprising:

a closed chamber comprising a transport system having at least one axis of rotation and adapted to move a substrate through and/or within the chamber,

a load-converting element arranged adjacent to at least one of the rotating shafts and adapted to detect a load acting on the at least one rotating shaft,

a measuring device for measuring an output signal of the load conversion element, an

A control device for monitoring and evaluating the output signal and detecting the presence or absence of the substrate on the at least one axis of rotation when the output signal differs from the first output signal by a predetermined amount, the first output signal being measured without a substrate on the at least one axis of rotation.

12. The apparatus of claim 11, wherein the at least one rotating shaft is held by a radial bearing disposed within a chamber wall, and the load transfer element is disposed within the bearing.

13. Apparatus according to claim 11 or 12, wherein a plurality of load converting elements are arranged adjacent to a plurality of rotation axes, and the control means is adapted to evaluate the output signals of all the load converting elements and to determine the weight or size of the substrate present on the rotation axes.

14. The device of any one of claims 11 to 13, wherein the load converting element is a piezoelectric element or a strain gauge.

15. Apparatus according to any one of claims 11 to 14, wherein the transport system comprises a plurality of rotation axes and is adapted to move substrates directly on the rotation axes, or the transport system comprises a belt supported by the at least one rotation axis and is adapted to move substrates on the belt.

16. The device according to any one of claims 11 to 15, wherein the closed chamber is a vacuum or atmospheric pressure chamber adapted to provide a reactive, corrosive or misty atmosphere and/or adapted to be heated to a temperature above 300 ℃, in particular above 500 ℃.

17. Apparatus according to any one of claims 11 to 16, wherein the closed chamber is a closed space sublimation chamber.

Technical Field

The present application relates to a method of determining a position of a substrate in a closed chamber of a substrate processing apparatus and an apparatus for performing the method. In particular, the invention relates to determining the position of a substrate moving within or through a chamber that is closed on all sides and may be a vacuum chamber.

Background

In many production processes, especially for large planar substrates, the substrate to be processed is moved within or through a chamber of a production line, especially an in-line system. Such substrates may be used to fabricate optoelectronic devices (e.g., solar cells or photosensors), or light emitting devices (e.g., light emitting diodes), or light transmitting devices (e.g., liquid crystal displays or touch screens), or other devices. Typically, the substrate is moved using a device such as a roller or shaft or belt. Furthermore, some of the processes performed are vacuum processes and the chambers used may be sealed, i.e. airtight, closed on all sides, e.g. by locks or doors. Even if the chamber is not closed on all sides but has small openings for inserting and removing substrates into and from the chamber, respectively, it is unlikely that conscious control by eye from outside the chamber will simply determine the position of the substrate within the chamber. Thus, according to the prior art, the position of the substrate is typically inferred from the movement of the mobile device or determined using optical or thermal sensors within the chamber.

However, extrapolation does not meet the need to accurately determine position, and when the substrate motion is subject to some disturbance, such as slipping of the substrate or due to breakage or damage of the substrate, position determination is simply not possible. Optical sensors cannot generally be used due to vapor (e.g., in an evaporation process) or plasma in a plasma process, or simply due to insufficient space or boresight within the chamber. Thermal sensors typically do not have the required spatial resolution. If the sensor is installed in the chamber, the sensor is subjected to high stress due to a process performed in the chamber, for example, high temperature in an evaporation process. Even if the sensor is mounted outside the chamber, as described in US2013/0206065a1, it is necessary to mount a sensor window within the chamber wall, resulting in a complicated chamber structure and further reducing the resolution and positioning accuracy of the sensor. Furthermore, it is difficult to detect local damage of the substrate, for example, damage of the substrate.

Content of application

It is an object of the present invention to provide a method for determining the position of a substrate within a closed chamber with high determination accuracy and which avoids at least some of the disadvantages of the methods according to the prior art. It is a further object to provide an apparatus for performing the method.

These objects are solved by a method and an arrangement, respectively, according to the independent claims. Embodiments are given in the dependent claims.

According to the present invention, a method of determining the position of a substrate in a closed chamber comprises the steps of: providing a load cell adjacent to at least one axis of rotation that is part of a transport system on which a substrate is moved within a chamber; measuring a first output signal of the load converting element without a substrate on the at least one rotation axis; monitoring the output signal of the load conversion element and detecting the presence of a substrate on the at least one rotational axis when the output signal of the load conversion element differs from the first output signal by at least a predetermined amount.

The transport system may comprise a plurality of rotating shafts disposed within the enclosed chamber, wherein the substrate moves directly on the rotating shafts, or may comprise at least one belt, such as a conveyor belt. The conveyor belt moves through the closed chamber and is supported by at least one rotating shaft within the chamber, wherein the substrate moves indirectly on the rotating shaft while resting on the belt. The substrate may be conveyed continuously, or discontinuously, i.e. with stops, e.g. to perform a process step, or oscillated, i.e. oscillated, bi-directionally or back and forth, one or more times.

The closed chamber may be any kind of vacuum or atmospheric pressure chamber in which any kind of atmosphere may be present, such as a reactive, corrosive or misty (fogged) atmosphere, when performing the method. The chamber may be sealed, i.e. airtight, closed on all sides, e.g. by a lock or door, or may have an opening for inserting or removing a substrate into or from it, respectively. However, it is not possible to simply determine the position of the substrate within the chamber by conscious control with the eye outside the chamber, and therefore the chamber is referred to as a closed chamber. Additionally or alternatively, the inside of the closed chamber may be heated to a temperature above 300 ℃, above 400 ℃, above 500 ℃ or even above 550 ℃ when performing the method. For such high temperatures, other methods of determining the position of the substrate using optical or thermal sensors according to the prior art are generally not applicable. The process performed in the closed chamber and acting on the substrate may be any kind of process, for example a temperature treatment process such as annealing, an evaporation process such as CSS (closed space sublimation), other deposition processes such as CVD (chemical vapor deposition), PVD (physical vapor deposition) or a structuring process such as dry etching. That is, the substrate may be temperature treated or layers may be deposited on or removed from the substrate while the substrate is within the chamber, for example a closed space sublimation process may be performed.

The load conversion element is adapted to detect a load acting on the rotating shaft and convert it into a value of an electrical parameter corresponding to the load. The value of the electrical parameter may be determined by measuring an electrical output signal corresponding to the electrical parameter. The load converting element may be a piezoelectric element comprising a piezoelectric material and two electrodes arranged on the piezoelectric material. The piezoelectric material converts the load into an electrical charge, thereby generating a voltage between the electrodes. This voltage can then be measured as an output signal by a measuring device. In another embodiment, the load converting element is a strain gauge, which is a resistor whose resistance changes if the resistor is stretched or compressed. The resistance, which is an electrical parameter to which the load is converted, can be determined by measuring the current at a given voltage applied to the resistor, wherein the current is the output signal of the strain gauge, which can be measured by the measuring means. Alternatively, the voltage may be measured for a given current. By "adjacent to the rotation axis" is meant that the load converting element is arranged such that it directly or indirectly abuts the rotation axis and such that a load acting on the rotation axis also acts directly or indirectly on the load converting element. That is, the load conversion element may be provided directly on the surface of the rotating shaft (for example, in the case of using a strain gauge), or may be provided in the vicinity of a bearing that is directly connected to the rotating shaft and holds the rotating shaft (for example, in the case of using a piezoelectric element).

In order to detect the presence of a substrate, a predetermined amount of the output signal has to be changed, which predetermined amount is selected such that noise of the output signal is not detected as a signal which erroneously corresponds to the presence of a substrate. For example, piezoelectric elements are very sensitive and low noise devices, so even the presence or absence of a lightweight substrate can be detected. For example, a load change of 0.5mN can be detected. The strain gauge also provides a good signal-to-noise ratio.

Since the position of the axis of rotation is known within the chamber, detecting the presence of the substrate according to the method of the invention corresponds to determining the position of the substrate within the closed chamber. Thus, the output signal changes from the first output signal to a value that differs from the first output signal by a predetermined amount, the change corresponding to a position of the substrate at which the leading edge of the substrate is at the position of the axis of rotation. If the output signal has a value that differs from the first output signal by a predetermined amount, the predetermined amount of the value corresponds to a position of a substrate covering a region within the chamber that contains the position of the axis of rotation. And, a change in the output signal from a value different by a predetermined amount from the first output signal to the first output signal corresponds to a position of the substrate at which the trailing edge of the substrate is at the position of the rotation axis.

The "rotation axis" means each rotation structure fixedly disposed within the chamber as a whole, and is adapted to directly or indirectly rotate and hold the substrate as it moves thereover. In this connection, "directly holding the substrate" means that the substrate or the substrate carrier holding the substrate is situated with one of its surfaces directly on the axis of rotation, while "indirectly holding the substrate" means that the substrate or the substrate carrier is situated with one of its surfaces on at least one belt, which in turn is held by the axis of rotation. In the latter case, the substrate itself is moved through the chamber by a belt, which is supported at least by a rotating shaft within the chamber. In any manner, the rotating shaft may be driven to rotate by a motor, i.e., may actively participate in transporting the substrate through the chamber, or may be passively rotated only by the substrate or a belt moving thereon. The axis of rotation may include various components, such as a substrate spindle on which the substrate is placed directly or indirectly, and a drive shaft that passes through the chamber wall and is coupled to the substrate spindle by a coupling. Furthermore, the rotation shaft may also comprise other elements. For example, a roller may be formed or disposed on a substrate shaft, with the substrate placed directly or indirectly on the roller.

"measuring" means determining the actual value of the output signal at a given point in time. "monitoring" refers to determining and observing the value of the output signal over time, thereby allowing different values to be compared and the change in the value of the output signal to be detected and the characteristics of the output signal over time to be obtained.

In one embodiment, the first point in time at which the substrate should be present on the axis of rotation is inferred by extrapolation using the known position of the substrate (e.g., outside the closed chamber) and the characteristics of the movement system that moves the substrate from the known position to the axis of rotation. The mobile system may be formed similarly to the transmission system, or may be formed in other ways. For example, the moving system may comprise a conveyor belt and the transport system only comprises a rotational axis, or vice versa, the transport system may comprise a conveyor belt and the moving system only comprises a rotational axis. The movement system may also comprise any other moving parts, such as a robotic system feeding the substrate to the transport system. Depending on the position of the axis of rotation used to detect the position of the substrate within the chamber and the type of transport system and movement system, the movement system may be the same as the transport system, i.e. the movement system is a transport system, or may comprise a transport system and other moving parts, or may be completely separate from the transport system. If at a first point in time no substrate is detected using the output signal of the load converting element, damage or loss of the substrate or disturbance of the substrate movement is detected. That is, the lack of an output signal corresponding to the presence of the substrate at the first point in time may be caused by damage to the substrate, e.g., breakage of a leading edge of the substrate, or total loss of the substrate, or may be caused by a defect of the moving system. A damaged substrate or an obstructed movement of the substrate may cause a delay in the detection of the output signal for a certain period of time. A total loss of the substrate, for example due to the substrate falling off the moving system, or the moving system failing completely, will result in no output signal corresponding to the presence of the substrate being detected at all. In this case, it may be necessary to visually inspect the closed chamber, for example by opening the chamber.

In another embodiment, not only is a change in the output signal observed, but a characteristic of the output signal as the substrate is moved on the axis of rotation is obtained and evaluated to determine other characteristics of the substrate. To this end, for a known calibration substrate, a first characteristic of the output signal, i.e. the variation of the output signal over time, is obtained. That is, the first characteristic is used for calibration of the output signal. The first characteristic includes a first gradient of the output signal corresponding to the calibration substrate reaching the rotation axis, a second gradient of the output signal corresponding to the calibration substrate leaving the rotation axis, and a maximum value corresponding to the substrate completely covering the rotation axis. For a plate-shaped and substantially rectangular substrate, the output signal is substantially equal to the maximum value over time when the substrate covers the rotation axis. The calibration substrate is a substrate having the same dimensions and characteristics as the other substrates whose position should be observed, wherein the calibration substrate is known to be undamaged. It moves in the same manner as other substrates by closing the chamber.

If such a first characteristic is obtained, damage of the substrate at its leading edge is detected if a first gradient of a second characteristic of the output signal, which is monitored when the substrate is moved fully on the rotation axis, is different from the first gradient of the first characteristic. The leading edge of the substrate is the edge that reaches the axis of rotation first, i.e. the leading edge in the transport direction. If the leading edge is damaged, e.g. if a portion of the leading edge is missing, the first gradient of the output signal is lower than the first gradient of the first characteristic. However, if the damage to the leading edge of the substrate is parallel to a previously undamaged leading edge, the damage may not be detected using the first gradient.

On the other hand, if a second gradient of a second characteristic of the output signal, which is monitored when the substrate is moved completely on the rotation axis, is different from the second gradient of the first characteristic, damage of the substrate at its rear edge is detected. The trailing edge of the substrate is the edge that is the last to leave the axis of rotation, i.e. the trailing edge in the transport direction. If the trailing edge is damaged, for example if a portion of the trailing edge is missing, the second gradient of the output signal is lower than the second gradient of the first characteristic. Likewise, if the damage of the trailing edge is parallel to the previously undamaged trailing edge, the damage may not be detected using the second gradient.

In addition, damage of the substrate on the side edge or the first surface is detected if a maximum value of the second characteristic of the output signal, which is monitored when the substrate is moved completely on the rotation axis, is smaller than a maximum value of the first characteristic. The side edge of the substrate is an edge connecting a front edge and a rear edge of the substrate, and the first surface of the substrate may be a surface of a plate-shaped substrate on which the substrate is placed on the rotation axis or on a surface opposite to the rotation axis.

The maximum value of the second characteristic obtained may also be lower than the maximum value of the first characteristic if the thickness of the layer formed on or at the substrate inside the closed chamber is smaller than the thickness of the calibration substrate. That is, the thinning process of the formed layer may be detected and such failure may be counteracted, for example, by reducing the speed of movement of the substrate through the chamber.

In another embodiment, a plurality of load converting elements are arranged adjacent to a plurality of rotational axes, wherein each load converting element is adapted to detect a load acting on one of said rotational axes. The output signal of each load converting element is measured at one and the same point in time in the presence of a substrate on at least some of the rotation axes. Using the measured output signals, the weight or size of the substrate is determined using a calculation program that is obvious to a person skilled in the art.

In one embodiment, the load transfer element is arranged within a radial bearing that holds the rotating shaft. If the output signal experiences a linear or super-linear drift over a period of time, including a large number of channels of substantially equal substrates on the axis of rotation, wear of the bearings is detected. The super-linear drift describes a function of the output signal over time that eventually grows faster than any linear function. Since the output signal from the passing substrate appears periodic, e.g., once per minute, long term drift can be identified and separated from the output signal generated by the substrate channel without any problem.

The method according to the invention provides a simple possibility to determine the position of a substrate within a closed chamber with high spatial resolution and without using other methods using optical or thermal sensors. In addition, damage to the substrate may also be detected, and the deposition or removal process may be controlled relative to the thickness of a layer deposited on or removed from the substrate within the closed chamber. Furthermore, the load conversion element used exhibits low noise, high sensitivity and high linearity of the output signal from the load. Piezoelectric elements have other advantages. In particular they do not require an external power source and are wear resistant.

According to another aspect of the invention, an apparatus for performing the method of the invention comprises: a closed chamber comprising a transport system having at least one axis of rotation; a load transfer element disposed adjacent to at least one of the rotating shafts; a measuring device for measuring an output signal of the load conversion element; and a control device for monitoring and evaluating the output signal and detecting the presence of the substrate on the at least one axis of rotation.

The transport system is adapted to move the substrate through and/or within the chamber and may comprise a plurality of rotating shafts arranged within the closed chamber, wherein the substrate moves directly on the rotating shafts, or may comprise at least one belt, e.g. a conveyor belt. The conveyor belt moves through the closed chamber and is supported by at least one rotating shaft within the chamber, wherein the substrate moves indirectly on the rotating shaft while resting on the belt. The load converting element is adapted to detect a load acting on at least one rotating shaft arranged adjacent thereto. The load conversion element converts the load into a value of an electrical parameter corresponding to the load. The value of the electrical parameter may be determined by measuring an electrical output signal corresponding to the electrical parameter using a measuring device. The measuring device is configured to obtain a first output signal, which is measured when no substrate is present on the at least one rotation axis. The control means is adapted to monitor the measured output signal and to detect the presence of a substrate on the axis of rotation when the output signal differs from the first output signal by a predetermined amount. The control means may be a computer, for example. However, the measuring means and the control means may also be formed as an integrated device adapted to perform the functions of both devices.

In one embodiment, the at least one rotational axis of the device is held by a radial bearing arranged within the chamber wall, and the load transferring element is arranged within said bearing. In this case, the load converting element is protected from external influences, such as for example steam or other aggressive media or high temperatures in the chamber. Further, strain caused by the load on the rotating shaft is easily detected in the bearing. The output signal of the load switching element may be transmitted to the measuring device via a wire and a vacuum feed-through.

However, the load converting element may be arranged at any position where deformation or strain of the rotation axis caused by the load of the substrate occurs and may be measured.

In another embodiment, the device comprises a plurality of rotation axes and a plurality of load transferring elements, wherein each load transferring element is arranged adjacent to a specific one of the rotation axes, and the control means is adapted to evaluate the output signals of all load transferring elements and to determine the weight or size of the substrate present on the rotation axes.

The load converting element may be a piezoelectric element or a strain gauge or any other suitable element.

The apparatus according to the invention may be part of an in-line system in which the substrate is processed while being moved along a straight line through the system by a transport system. The transport system may comprise a plurality of rotating shafts disposed within the enclosed chamber, wherein the substrate moves directly on the rotating shafts, or may comprise at least one belt, such as a conveyor belt. The conveyor belt moves through the closed chamber and is supported by at least one rotating shaft within the chamber, wherein the substrate moves indirectly on the rotating shaft while resting on the belt. The transport system is adapted to transport the substrate continuously, or discontinuously, i.e. with a stop, for example to perform a process step, or to oscillate, i.e. to oscillate one or more times, bidirectionally or back and forth.

The closed chamber may be any kind of vacuum chamber or atmospheric pressure chamber as described above. In one embodiment, the closed chamber is a vacuum chamber, and may in particular be a Closed Space Sublimation (CSS) CSS chamber, such as CdTe or CdS, in order to produce thin film solar cells.

Drawings

The accompanying drawings are included to provide a further understanding of embodiments of the invention, and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate some embodiments of the invention and together with the description serve to explain the principles. Other embodiments of the present invention and many of the intended advantages will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.

Fig. 1 schematically shows a first embodiment of the method of the invention, in which the presence of a substrate on one axis of rotation is detected.

Fig. 2A schematically shows a second embodiment of the method of the invention, wherein damage or loss of the substrate or disturbance of the movement of the substrate can be detected.

Fig. 2B schematically shows two characteristics of the output signal over time according to the second embodiment of the method.

Fig. 3A schematically shows a third embodiment of the method of the invention, in which damage to the substrate can be detected.

Fig. 3B-3D each schematically show the behavior of the output signal over time according to a third embodiment of the method.

Fig. 4A schematically shows a fourth embodiment of the method of the invention, in which a plurality of load converting elements may be used to determine the size of the substrate.

Fig. 4B schematically shows the values of the output signals for different load converting elements according to a fourth embodiment of the method.

Fig. 5 schematically shows a first embodiment of the device according to the invention.

Fig. 6 schematically shows a first example of a rotating shaft and a load transforming element arranged in a bearing of a first embodiment of the device.

Detailed Description

Fig. 1 shows a first embodiment of the method of the invention. In a first step S110, a load transfer element, such as a piezoelectric element or strain gauge, is disposed adjacent to the axis of rotation within the enclosed chamber and at least serves to support the substrate during movement of the substrate within and/or through the chamber. The rotation axis may be actively rotated, i.e. driven by a motor or any other means, and may thus be an active part of moving the substrate, or the rotation axis may be passively rotated, i.e. passively rotated by the movement of the substrate on the rotation axis. In a second step S120, a first output signal of the load converting element is measured when no substrate is present on the rotation axis, i.e. the first output signal is a freewheel signal having a first value. During the movement of the substrate inside or through the sealed chamber, the output signal of the load conversion element is monitored (step S130), and when the output signal differs from the first output signal by a predetermined amount, the presence or absence of the substrate on the rotation axis is detected (step S140). Thus, if the presence of the substrate is detected for the first time, the substrate just reaches the axis of rotation in its movement. If the presence of the substrate is continuously detected, the substrate moves any part of its extension onto the rotation axis. And, if the presence of the substrate is no longer detected, i.e. the output signal changes back from a value differing from the first output signal by a predetermined amount to the first output signal, the substrate just leaves the axis of rotation. In this way, the position of the substrate within the closed chamber can be detected.

Fig. 2A shows a second embodiment of the method, wherein damage or loss of the substrate or disturbance of the movement of the substrate can be detected. Fig. 2B schematically shows two characteristics of the output signal over time according to the second implementation and helps to explain the second embodiment. Steps S210 and S220 are the same as steps S110 and S120 of fig. 1. The value of the first output signal measured in step S220 is represented by S in FIG. 2B₁And (4) showing. In step S230, a first point in time at which the substrate should be present on the rotation axis is inferred based on the known position of the substrate at a given point in time and the characteristics of the movement system moving the substrate from the known position to the rotation axis, in particular the speed of movement. The first time point is shown by t in FIG. 2A₁₁And (4) showing. Then, the output signal of the load conversion element is monitored (step S240). If at a first point in time t₁₁On which the presence of the substrate is not detected, the following can be concluded: the substrate has been damaged, i.e. the front edge of the substrate has been damaged, or the substrate has been lost, i.e. dropped from the moving system, or the movement of the substrate is disturbed, e.g. because the moving system has failed. In a first exemplary characteristic of the monitored output signal over time, as illustrated by the fact in FIG. 2BLine indicates that the output signal reaches a second value S₂Second value S₂And a first output signal S₁Differ by a predetermined amount and thus indicate the presence of the substrate on the axis of rotation at a second point in time t₁₂At a second point in time t₁₂Different from the first point in time. In this case, it can be concluded that the substrate has been damaged at its front edge or that the moving system is blocked. In a second exemplary characteristic of the monitored output signal over time, as shown by the dashed line in fig. 2B, the output signal never reaches the second value S₂But instead remains at the value S₁. In this case, the following conclusions can be drawn: the substrate may be lost or the moving system may fail completely. It is obvious that it is not always possible to make an exact statement as to what happens.

Fig. 3A shows a third embodiment of the method, wherein damage to the substrate can be detected and can be determined in a more detailed manner than in the second embodiment. Fig. 3B-3D schematically show the time-varying characteristics of the output signal of the load conversion element and plan views of different types of damage to the substrate 10 on the substrate 10 and the rotation axis 20, respectively. Step S310 is the same as step S110 in fig. 1. In step S320, the first output signal S is measured not only as described in step S120 of FIG. 1₁And the first characteristic of the output signal is obtained while the calibration substrate is moved on the rotation axis. These first characteristics are indicated in fig. 3B and 3D by dashed lines, wherein this dashed line is only visible when the "actual" substrate is moved on the rotation axis, as it differs from the second characteristics of the output signal obtained by monitoring the output signal. Exemplary second characteristics are indicated by solid lines in fig. 3B to 3D and dotted lines in fig. 3D. The calibration substrate is a substrate of known size, weight and integrity (i.e. without any damage). The "actual" substrate is one that should generally be the same as the calibration substrate, but may be damaged, or may be different in size or weight from the calibration substrate. The characteristic of each characteristic of the output signal for the substrate comprises a first gradient, a maximum S, corresponding to the arrival of the substrate at the rotation axis₃And a second gradient corresponding to the substrate moving away from the axis of rotation. The first gradient is calculated as the maximum S₃And a first output signal S₁The difference therebetween and a third point in time t₂₁And a fourth time point t₂₂The quotient of the first time period in between. During a first time period, the output signal is derived from the first output signal S₁Becomes the maximum value S₃. The second gradient is calculated as the first output signal S₁And a maximum value S₃Difference therebetween and a fifth point in time t₂₃And a sixth time point t₂₄The quotient of the second time period in between. During the second time period, the output signal is from the maximum value S₃Becomes a first output signal S₁. For a rectangular, undamaged substrate, the output signal is most of the time equal to the maximum value S when the substrate is present on (i.e., moving on) the axis of rotation₃. This is illustrated in the exemplary characteristics of fig. 3B-3D.

In step S330, a second characteristic of the output signal is obtained by monitoring the output signal while the "actual" and possibly damaged substrate is moved on the rotation axis. In step S340, the features of the second characteristic are compared with the respective features of the first characteristic, and when the features are different from each other, as described below, a specific damage of the substrate is detected.

Fig. 3B shows a plan view of the substrate 10 and the rotation axis 20, wherein the substrate 10 is damaged at its front edge 11. I.e. the area 11' adjoining the front edge 11 is broken and is therefore called broken area. The leading edge 11 is the edge of the substrate 10 which first reaches the axis of rotation 20 when the substrate 10 is moved in the direction indicated by the arrow. The load cell 30 is disposed adjacent to the rotating shaft 20 and measures the load acting on the rotating shaft 20. The break-off region 11' results in a slower increase of the measured output signal, i.e. a smaller first gradient of the second characteristic compared to the first gradient of the first characteristic. Therefore, at the delayed fourth time point t'₂₂Is at the maximum value S₃Wherein a third point in time t of the second characteristic₂₁And a fourth delayed time point t'₂₂A first time period in between is larger than a third point in time t of the first characteristic₂₁And a fourth time point t₂₂A first time period in between. Other features of the second characteristic may be the same as the first characteristic.

Fig. 3C shows a plan view of the substrate 10 and the rotation axis 20, wherein the substrate 10 is damaged at its rear edge 12. That is, the area 12' adjacent the trailing edge 12 is broken and is therefore referred to as a broken area. The trailing edge 12 is the edge of the substrate 10 that eventually moves away from the axis of rotation 20 as the substrate 10 moves in the direction indicated by the arrow. The disconnection region 12' results in a slower decrease of the measured output signal, i.e. a smaller second gradient of the second characteristic compared to the first gradient of the first characteristic. Thus, the output signal is at the fifth advanced time point t'₂₃Starting from the maximum value S₃Begins to decrease with the second characteristic at a fifth point in time t 'ahead'₂₃And a sixth point in time t₂₄A fourth point of time t between which the second time period characteristic is greater than the first characteristic₂₃And a sixth point in time t₂₄A second time period in between. Other features of the second characteristic may be the same as the first characteristic.

Third to sixth time points t₂₁To t₂₄And a delayed fourth time point t'₂₂And an advanced fifth time point t'₂₃But is a relative measure of time and does not represent an absolute point in time at which the respective output signal is measured.

Fig. 3D shows a plan view of the substrate 10 and the rotation axis 20, wherein the substrate 10 is damaged at the side edge 13 or at the first surface 14. I.e. the area 13' adjoining the side edge 13 is broken, and is therefore called broken area. The side edge 13 is an edge of the substrate 10 that extends in the direction of movement of the substrate 10 (indicated by the arrow). The laterally confined area 14', which is part of the first surface 14, is damaged and is therefore referred to as a damaged surface area. The first surface 14 is a plane of the substrate 10, i.e., a lower surface in contact with the rotation axis 20 or an upper surface opposite to the lower surface. The broken-off region 13 'or the damaged surface region 14' leads to a measured output signal from a maximum S₃Decrease to the timely limit decrease value S₃₁That is, the output signal is below the maximum value S for a defined period of time, as shown by the continuous second characteristic of the output signal over time_3。However, if the entire first surface 14 is damaged, i.e. the damaged area is not laterally limited, then this is indicated by the dotted lineThe second characteristic of the shown exemplary characteristics does not reach the maximum value S of the first characteristic at all₃. That is, the output signal of the second characteristic reaches only the reduced maximum value S₃₂The maximum value S of the reduction₃₂Less than a maximum value S₃. Such damage may be, for example, the thickness of a layer deposited on the substrate 10, wherein the thickness is less than the thickness of the individual layers of the calibration substrate. Therefore, the weight of the substrate 10 is smaller than the weight of the calibration substrate. Other features of the second characteristic may be the same as the first characteristic.

Of course, some of the impairments explained above may occur simultaneously, resulting in a combination or overlap of said variations in the characteristics of the output signal characteristics.

Furthermore, it is obvious to a person skilled in the art that the specific course of the first and second characteristics depends on the kind of electrical parameter into which the load converting element converts the load and on the kind of output signal which corresponds to the electrical parameter and which is measured and monitored. Therefore, the output signal may also be reduced in the case where the substrate is present on the rotation axis, compared to the first output signal in the case where the substrate is not present. In other words: the first and second characteristics may also operate in the opposite way and the maximum value of the output signal may alternatively be the minimum value of the output signal.

Fig. 4A shows a fourth embodiment of the method, in which a plurality of load converting elements may be used to detect the size of the substrate. Fig. 4B schematically shows the values of the output signals of the different load converting elements at a given point in time, and a plan view on the substrate 10 and the plurality of rotary shafts 20a-20f at the given point in time. In a first step S410, a plurality of load converting elements 30a to 30f are provided, wherein each individual load converting element 30a to 30f is arranged adjacent to one of the plurality of rotational shafts 20a to 20 f. That is, part or all of the rotating shafts forming part of the transport system within the closed chamber are provided with one load transferring element, wherein in the example shown each rotating shaft 20a to 20f is provided with one load transferring element 30a to 30 f. In the second step S420, similarly to step S120 of FIG. 1, in the case where no substrate is present on each of the rotating shafts 20a to 20fUnder the condition that the first output signal S of each load converting element 30a-30f is measured₁. During the movement of the substrate 10 on the rotation axes 20a-20f, the output signals of the load conversion elements are monitored (step S430), and when the respective output signals differ from the first output signal S1 by a predetermined amount (e.g., when the respective output signals are equal to or greater than the second value S1)₂In time), it is detected whether or not a substrate is present on a single one of the rotation axes 20a-20f (step S440). For example, since the substrate 10 exists on the respective rotation axes 20b to 20d, the output signals of the load conversion elements 30b to 30d are larger than the second value S₂. In contrast, since the substrate 10 is not present on the respective rotation shafts 20a, 20e, and 20f, the output signals of the load conversion elements 30a, 30e, and 30f are equal to the respective output signals S₁. As shown in fig. 4B, the output signals of the different load conversion elements 30B to 30d may differ from each other due to the difference in the load conversion elements and their load conversion themselves, or due to the difference in the load acting on the load conversion elements (i.e., the weight of the substrate portions located on the respective rotation shafts 20B to 20 d). Also, the first output signal S is for different rotation axes 20a to 20f₁The values of (c) may also be different. The slave axis (the output signal of which is equal to the first output signal S1 and equal to or greater than the second value S₂Adjacent to the axis of rotation of (e.g. 20a and 20e) in fig. 4B) by a known distance L₂₀₁And covering the rotating shaft (the output signal of which is equal to or greater than the second value S)₂Known extension L of a line, for example 20B to 20d) in FIG. 4B)₂₀₂The length L of the substrate 10 can be determined₁₀. Length L₁₀May be at least limited to be larger than the extension L₂₀₂And is less than the distance L₂₀₁A range of values of (c). By evaluating the maximum value of the output signal, the width of the substrate 10 can also be determined. Length L of substrate₁₀Refers to the extension of the substrate in the direction of motion (indicated by the arrow), and the width of the substrate refers to the substrate and the length L₁₀An extension orthogonal to and extending in the direction of the rotational axis of the rotary shafts 20a-20 f.

Fig. 5 schematically shows a first embodiment of the device according to the invention. The apparatus 100 includes a closed chamber 110 and two adjacent chambers 120 and 130, the chambers 120 and 130 being connected to the closed chamber 110 by a door 140. In the closed chamber 110, a plurality of rotating shafts 20a to 20e are arranged, which together with the rotating shafts 20 arranged in the adjacent chambers 120 and 130 form a transport system for moving substrates through the chambers in a transport direction (indicated by arrows). At least one load conversion member is disposed adjacent to at least one of the rotating shafts 20a to 20e in the hermetic chamber 110. As shown in the example in fig. 5, two load conversion members 30a and 30b are disposed adjacent to the rotation shafts 20b and 20 d. Each load converting element 30a, 30b is connected to a measuring device 40a, 40b, respectively, which measuring device 40a, 40b is adapted to measure the output signal of the respective load converting element 30a, 30 b. Of course, some or all of the output signals may be measured by applicable general purpose measuring devices. The measured output signal is transmitted to a control device 50, which control device 50 is adapted to monitor and evaluate the output signal. For this purpose, the value or characteristic of the output signal and the reference value may be stored in a memory unit, which may be arranged within the control device or outside the control device. The control means comprises comparison means and may comprise computing means or other means suitable for evaluating the output signal. Based on this evaluation, the control device determines whether there is a substrate on one of the rotating shafts 20B or 20d provided with the load-converting elements 30a, 30B, or the damage, weight, or size of the substrate as exemplarily depicted in fig. 2A-4B.

At least one of the rotary shafts 20 and 20a to 20e is connected with a driving device, wherein in the embodiment of fig. 5, each rotary shaft, which is not provided with a load conversion member, i.e., the rotary shaft 20 in the chambers 120 and 130 and the rotary shafts 20a, 20c and 20e in the hermetic chamber 110, is connected with the respective driving device 60. However, the rotary shaft provided with the load conversion element may be connected to the driving device. These rotary shafts are hereinafter referred to as driven shafts. Some or all of the driven shafts may also be connected to a common drive. The follower shaft allows the substrate to move through chambers 110, 120, and 130. The drive means 60 may be connected to the control means 50 such that the control means 50 may control the drive means 60 and thereby the movement, in particular the speed, of the substrates through the chambers 110, 120 and 130.

Fig. 6 schematically shows a first example of a rotary shaft and a load conversion element according to the invention in a cross-sectional view along the axis of rotation of the rotary shaft. The rotation axis comprises different parts: a substrate shaft 21 disposed within the hermetic chamber 110, a driving shaft 24 passing through a first sidewall 111 of the hermetic chamber 110 and adapted to be connected to a driving means, and a coupling 25. The shaft coupling 25 couples the substrate shaft 21 and the drive shaft 24 together so that rotation of the drive shaft 24 is transmitted to the substrate shaft 21 and vice versa. On the substrate spindle 21, two outer casters 22 and one inner caster 23 are arranged, wherein the casters 22 and 23 are fixedly secured to the substrate spindle 21 and move together with the substrate spindle 21. They may be formed integrally with the substrate spindle 21, i.e. they may be protrusions of the substrate spindle. The substrate is only or mostly located on these castors 22 and 23, wherein the outer castors 22 are used to guide the side edges of the substrate to ensure the direction of movement of the substrate. One end of the substrate shaft 21 passes through a second sidewall 112 of the hermetic chamber 110, the second sidewall 112 being opposite to the first sidewall 111. The other end of the substrate shaft 21 is located in the coupling 25, and the other end of the drive shaft 24 is also located in the coupling 25. Drive shaft 24 passes through first sidewall 111 and is retained by first bearing 160 disposed within feedthrough 150. If the enclosed chamber 110 is a vacuum chamber, the feedthrough 150 is a vacuum feedthrough. One end of the substrate shaft 21 is held by a second bearing 161, which second bearing 161 is closed to the environment by a blind flange 170. The first bearing 160 and the second bearing 161 may be any bearing suitable for supporting various portions of the rotating shaft without affecting the environmental conditions, particularly the vacuum conditions, within the hermetic chamber 110. For example, the bearing may be a ball bearing. In one embodiment, the bearings 160, 161 are disposed on the outside, i.e., on the atmospheric side, of the respective side wall 111 or 112 of the closed chamber. Adjacent to the first bearing 160, a load transfer element 30 is arranged, so that the load transfer element 30 can transfer the load acting on the substrate shaft 21, which is transmitted by the coupling 25 to the drive shaft 24 and the first bearing 160. Thus, the load converting element 30 is arranged outside the closed chamber 110 and thus outside the process atmosphere, which is advantageous in that the load converting element 30 is protected from adverse environmental conditions within the chamber 110, such as steam, electromagnetic fields or high temperatures. However, the load converting element may be arranged at any point where a load causes a deformation, which may be converted into an electrical parameter.

The materials of the rotary shaft 20, in particular the substrate shaft 21, the coupling 25 and the drive shaft 24, the load transfer element 30 and, if applicable, the bearings 160, 161 and the feed-through 150 depend on the conditions related to the processing of the substrate in the chamber 110 and on the position of the load transfer element 30 relative to the chamber 110. The rotating shaft 20, bearings 160, 161, and feedthrough 150 may be formed of stainless steel. The rotating shaft 20 may preferably be made of ceramic due to the high process temperatures within the chamber 110. If the load converting element 30 is a piezoelectric element, for example, SiO is known to those skilled in the art₂，GaPO₄，La₃Ga₅SiO₁₄Different materials such as polyvinylidene fluoride (PVDF). In addition, with different time resolution (from quasi-static (0.001Hz) to high dynamic (GHz)) and different power resolution (from 10)^-8N/cm²To 10⁵N/cm²) Are available. Furthermore, various surface adapters are known, such as a ball or concave top piece, to provide load transfer from the rotating shaft or bearing to the piezoelectric element. The substrate spindle may have a length (extension along the axis of rotation) of about 450mm and a diameter of about 45 mm. If it is made of ceramic, its weight may be, for example, about 1.35kg, wherein the rotating shaft made of stainless steel may weigh about 5.4 kg. The drive shaft may be shorter in length (e.g., 150mm) and smaller in diameter (e.g., 12 mm) and thus lighter in weight. The planar surface area was (30X50) cm²The weight of the substrate (2) is about 1.2 kg, and the planar surface area is (60x120) cm²The weight of the substrate of (1) is about 5.76 kg.

The embodiments of the present invention described in the foregoing description are given as examples, and the present invention is not limited thereto. Any modifications, variations and equivalent arrangements as well as combinations of the embodiments are to be considered as included within the scope of the present invention.

Reference numerals:

10 substrate

11 front edge

11' front edge breaking region

12 rear edge

12' rear edge breaking region

13 side edge

13' side edge break-off region

14 first surface

20, 20a-20f rotary shaft

21 substrate spindle

22 outer castor

23 inner castor

24 drive shaft

25 shaft coupling

30a-30f load transfer element

40a, 40b measuring device

50 control device

60 drive device

100 device

110 closed chamber

111 first side wall of a closed chamber

112 second side wall of the closed chamber

120, 130 adjacent chambers

140 door

150 feed-through

160 first bearing

161 second bearing

170 blind flange

L₁₀Length of substrate

L₂₀₁Distance between the axes of rotation

L₂₀₂Extension part of rotating shaft

S₁First output signal

S₂Second value of output signal

S₃Maximum value of output signal

S₃₁Timely limiting reduction value of output signal

S₃₂Reduced maximum value of output signal

t₁₁First point in time

t₁₂Second point in time

t₂₁Third time point

t₂₂A fourth point in time

t’₂₂Delayed fourth point in time

t₂₃Fifth time point

t’₂₃Fifth point of time of advance

t₂₄The sixth time point