Magnetic levitation system and method for measuring the distance between at least one electromagnetic actuator and a ferromagnetic element

Abstract

A magnetic levitation system (100) for magnetically levitating a ferromagnetic element (150) is described. The magnetic levitation system (100) includes at least one electromagnetic actuator (178), the at least one electromagnetic actuator being coupled to one or more transformers (140) disposed in a current supply system (135), the current supply system (135) being used to supply current to the at least one electromagnetic actuator (178). In addition, a substrate processing system including the magnetic levitation system and a method for measuring a distance between at least one electromagnetic actuator and a ferromagnetic element are described.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a magnetic levitation system for magnetically levitating a ferromagnetic element. In particular, embodiments of the present disclosure relate to a magnetic levitation system for contactless transport of a carrier, in particular in a substrate processing system. Additionally, embodiments of the present disclosure relate to a method for measuring a distance between at least one electromagnetic actuator and a ferromagnetic element, in particular, the ferromagnetic element being connected to a carrier for holding a substrate. Background Art

[0002] Systems for performing various processes such as coating a substrate in a processing chamber are known. Several methods for depositing materials on a substrate are known. For example, a substrate can be coated using an evaporation process, a physical vapor deposition (PVD) process such as a sputtering process, a spraying process, or a chemical vapor deposition (CVD) process. The process can be performed in a processing chamber of a deposition apparatus where the substrate to be coated is located. The deposited material is disposed in the processing chamber. A variety of materials such as small molecules, metals, oxides, nitrides, and carbides can be used for deposition on the substrate. In addition, other processes such as etching, structuring, annealing, etc. can be performed in the processing chamber.

[0003] For example, for example in display manufacturing technology, a coating process may be considered for a large area substrate. The coated substrate may be used in several applications and in several technical fields. For example, an application may be an organic light emitting diode (OLED) panel. Other applications include insulating panels, microelectronic devices (such as semiconductor devices), substrates with thin film transistors (TFTs), color filters, etc. OLED is a solid-state device composed of (organic) molecular films that generates light by applying electricity. As an example, an OLED display may provide a bright display on an electronic device and use reduced power compared to, for example, a liquid crystal display (LCD). In a processing chamber, organic molecules are generated (e.g., evaporated, sputtered, or sprayed, etc.) and deposited in layers on a substrate. The particles may, for example, pass through a mask having a boundary or a specific pattern to deposit material at a specific position on the substrate, for example, to form an OLED pattern on the substrate.

[0004] The processing system typically comprises a transport system for guiding the carrier in the processing chamber (e.g. during a coating process). For example, the transport system may be adapted to provide the carrier at a processing position and / or for transporting the carrier within the processing chamber. The transport system may be configured for magnetic levitation and may comprise one or more magnetic bearings. In order to measure the distance between the carrier and the magnetic bearing, a separate distance sensor is typically provided. However, a separate distance sensor has the disadvantage of requiring additional installation space and increasing complexity. In particular, the use of known distance sensors involves ultrafast and high-resolution measurement signal analysis. In addition, conventional distance measurement methods involve complex signal processing models to determine position information from the magnetic bearing actuator, in particular from high-bandwidth and high-resolution current measurements.

[0005] Therefore, there is a continuing need for an improved carrier transport system that at least partially overcomes some of the problems of the prior art, particularly with respect to measuring the distance between a magnetic bearing actuator and a carrier. In addition, there is a continuing need for an improved method of measuring the distance between a magnetic bearing actuator and a carrier that can overcome at least some of the problems in the prior art. Summary of the invention

[0006] In view of the above, a magnetic levitation system and a method of measuring the distance between at least one electromagnetic actuator and a ferromagnetic element according to the independent claims are provided. Further aspects, advantages and features are apparent from the dependent claims, the description and the drawings.

[0007] According to one aspect of the present disclosure, a magnetic suspension system for magnetically levitating ferromagnetic elements is provided. The magnetic suspension system includes at least one electromagnetic actuator. The at least one electromagnetic actuator is coupled to one or more transformers. The one or more transformers are arranged in a current supply system, and the current supply system is used to supply current to the at least one electromagnetic actuator.

[0008] According to another aspect of the present disclosure, a magnetic levitation system for magnetically levitating ferromagnetic elements is provided. The magnetic levitation system includes at least one electromagnetic actuator, one or more transformers, a current supply system, and a signal evaluation unit. At least one electromagnetic actuator is electrically coupled to one or more transformers. One or more transformers are disposed in the current supply system. The current supply system is configured to supply current to at least one electromagnetic actuator. One or more transformers have a secondary winding. The secondary winding is configured to provide an output signal to the signal evaluation unit. The signal evaluation unit is configured to determine a distance between at least one electromagnetic actuator and the ferromagnetic element based on the output signal.

[0009] According to another aspect of the present disclosure, a substrate processing system is provided, which includes the magnetic levitation system according to any embodiment of the present disclosure.

[0010] According to another aspect of the present disclosure, a method for measuring a distance between at least one electromagnetic actuator and a ferromagnetic element is provided. The method includes measuring an inductance of at least one electromagnetic actuator. The step of measuring the inductance includes measuring one or more output signals provided by one or more secondary windings of one or more transformers. The one or more transformers are arranged in a current supply system, which is used to supply current to the at least one electromagnetic actuator.

[0011] According to another aspect of the present disclosure, a method for manufacturing a coated substrate, in particular a coated substrate for manufacturing an electronic device, is provided. The method comprises using a magnetic levitation system according to any embodiment of the present disclosure.

[0012] Embodiments are also directed to devices for performing the disclosed methods, and include device components for performing the described method aspects. These method aspects can be performed by means of hardware components, computers programmed by appropriate software, any combination of the two, or in any other manner. In addition, embodiments according to the present disclosure also relate to methods for operating the described devices. The methods for operating the described devices include method aspects for performing each function of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to understand in detail the manner in which the above-mentioned features of the present disclosure are achieved, a more specific description of the present disclosure briefly summarized above may be obtained by reference to the embodiments. The accompanying drawings relate to embodiments of the present disclosure and are described as follows:

[0014] Figure 1 shows a schematic diagram of a magnetic levitation system according to embodiments described herein;

[0015] Figures 2 to 4 shows a schematic diagram of a magnetic levitation system according to another embodiment described herein;

[0016] Figure 5 shows a schematic diagram of a substrate processing system according to embodiments described herein;

[0017] Figure 6 A flow chart for illustrating a method of measuring a distance between at least one electromagnetic actuator and a ferromagnetic element according to embodiments described herein is shown; and

[0018] Figure 7 An exemplary test signal S is shown for illustrating an exemplary test signal S according to the embodiments described herein. testand an exemplary output signal S out . DETAILED DESCRIPTION

[0019] Reference will now be made in detail to various embodiments of the present disclosure, one or more examples of which are shown in the accompanying drawings. In the following description of the drawings, the same reference numerals refer to the same components. Only the differences relative to a separate embodiment are described. Each example is provided in a manner to explain the present disclosure and is not intended to be a limitation of the present disclosure. In addition, the features shown or described as part of an embodiment may be used on other embodiments or used in combination with other embodiments to produce additional embodiments. This specification is intended to include such modifications and variations.

[0020] For example, reference Figure 1 , describes a magnetic levitation system 100 for magnetically levitating a ferromagnetic element 150 according to the present disclosure. According to embodiments that can be combined with other embodiments described herein, the magnetic levitation system 100 includes at least one electromagnetic actuator 178. Typically, during operation, as Figure 1 As indicated, a distance x is provided between the at least one electromagnetic actuator 178 and the ferromagnetic element 150. The at least one electromagnetic actuator 178 is coupled to one or more transformers 140. The one or more transformers 140 are arranged in a current supply system 135, and the current supply system 135 is used to supply current to the at least one electromagnetic actuator 178. Typically, as Figure 1 As shown exemplarily, the current supply system 135 includes a power source 131. The power source 131 is configured to provide current to at least one electromagnetic actuator 178. Figure 1 The arrow I in the figure exemplarily indicates the direction of current flow. Figure 1 A coordinate system having a first direction 192, a second direction 194, and a third direction 196 is shown. Typically, the first direction 192 is the carrier transport direction, the second direction 194 is a vertical direction, and the third direction 196 may be a direction transverse to the carrier transport direction. In addition, it will be understood that at least one electromagnetic actuator 178 is electrically coupled to one or more transformers 140. More specifically, as Figure 1 As schematically shown, at least one electromagnetic actuator 178 may be inductively coupled to one or more transformers 140 .

[0021] Therefore, a magnetic levitation system is provided, which is improved in measuring the distance between a magnetic bearing actuator and a carrier, in particular between an electromagnetic actuator and a ferromagnetic element (for example, a ferromagnetic element is connected to the carrier or is part of the carrier). More specifically, a magnetic levitation system with a self-sensing actuator is provided by providing one or more transformers coupled to at least one electromagnetic actuator. "Self-sensing actuator" can be understood as not requiring an additional separate sensor for position or distance measurement. In other words, the magnetic levitation system as described herein has the advantage that information about the distance between the electromagnetic actuator and the ferromagnetic element can be obtained without the need for an additional position sensor or distance sensor.

[0022] In particular, the magnetic levitation system of the present disclosure is advantageously configured to provide an output signal at one or more transformers coupled to at least one electromagnetic actuator. The output signal can be used to determine the distance between the electromagnetic actuator and the ferromagnetic element, which is typically connected to the carrier. Therefore, compared to the prior art, the advantage of the magnetic levitation system according to the embodiments described herein is that distance measurement is facilitated. In particular, compared to conventional methods for distance measurement, the magnetic levitation system described herein is advantageously configured to provide an output signal of the transformer, which can be more easily processed and evaluated to determine the distance and / or position information of the ferromagnetic element relative to the electromagnetic actuator.

[0023] For example, reference Figure 1 According to an embodiment that can be combined with other embodiments described herein, the one or more transformers 140 have a voltage for providing one or more output signals S of the one or more transformers 140. out The electrical connection 144. Typically, as Figure 2 As shown exemplarily, one or more transformers 140 have a primary winding 141 electrically connected to the current supply system 135. In addition, typically, one or more transformers 140 have a secondary winding 142 inductively coupled to the primary winding 141. In particular, as Figure 2 As exemplarily shown, the electrical connection 144 is electrically connected to the secondary winding 142 of the one or more transformers 140 .

[0024] According to embodiments that can be combined with other embodiments described herein, as shown in reference Figure 4 As exemplarily described, at least one electromagnetic actuator 178 is part of the suspension unit 175. Typically, as Figure 2 As shown in an exemplary manner, at least one electromagnetic actuator 178 includes a coil 178A and at least one ferromagnetic core 178B. The coil 178A is electrically connected to the current supply system 135 .

[0025] When current is applied to coil 178A, at least one electromagnetic actuator 178 generates a magnetic field. The magnetic field generated by at least one electromagnetic actuator 178 applies a magnetic levitation force to ferromagnetic element 150 in second direction 194, causing carrier 110 to which ferromagnetic element 150 is attached to levitate.

[0026] like Figure 2 As shown exemplarily, according to an embodiment that can be combined with other embodiments described herein, the current supply system 135 includes a first line 135A for conducting current from the power source 131 to the at least one electromagnetic actuator 178. In addition, the current supply system 135 includes a second line 135B for conducting current from the at least one electromagnetic actuator 178 to the power source 131. One or more transformers 140 are disposed in at least one of the first line 135A and the second line 135B.

[0027] For example, reference Figure 2 According to an embodiment that can be combined with other embodiments described herein, the one or more transformers include a first transformer 140A and a second transformer 140B. The first transformer 140A has a first primary winding 141A electrically connected to the first line 135A. In addition, the first transformer 140A has a first secondary winding 142A, in particular inductively coupled to the first primary winding 141A. Typically, the first secondary winding 142A is provided for providing a first output signal S out1 The second transformer 140B has a second primary winding 141B electrically connected to the second line 135B. In addition, the second transformer 140B has a second secondary winding 142B, which is inductively coupled to the second primary winding 141B. Typically, the second secondary winding 142B is provided for providing a second output signal S out2 Electrical connection 144.

[0028] For example, reference Figure 3 According to an embodiment that can be combined with other embodiments described herein, the current supply system 135 further includes an amplifier 132 and a test signal unit 133. In particular, the test signal unit 133 is configured to convert the test signal S test Added to the output of amplifier 132.

[0029] According to an embodiment that can be combined with other embodiments described herein, the magnetic levitation system further comprises a signal evaluation unit 145, which is configured to acquire or read out the output signal S of the one or more transformers 140. out Typically, such as Figure 3As shown exemplarily, the signal evaluation unit 145 is connected to the electrical connection 144. Therefore, it will be understood that the signal evaluation unit 145 is typically configured to acquire or read out the first output signal S provided by the first secondary winding 142A. out1 and / or obtaining or reading the second output signal S provided by the second secondary winding 142B out2 .

[0030] In particular, it should be understood that the signal evaluation unit 145 is configured to generate a signal based on the output signal S of the one or more transformers 140. out To determine the distance between the at least one electromagnetic actuator 178 and the ferromagnetic element 150. Typically, the signal evaluation unit 145 comprises an analog-to-digital converter.

[0031] According to an example that can be combined with other embodiments described herein, a magnetic levitation system 100 for magnetically levitating a ferromagnetic element 150 is provided. The magnetic levitation system 100 includes at least one electromagnetic actuator 178, one or more transformers 140, a current supply system 135, and a signal evaluation unit 145. The at least one electromagnetic actuator 178 is electrically coupled to the one or more transformers 140. The one or more transformers 140 are disposed in the current supply system 135. The current supply system 135 is configured to supply current to the at least one electromagnetic actuator 178. The one or more transformers 140 include a current supply system 135 configured to provide an output signal S to the signal evaluation unit 145. out The signal evaluation unit 145 is configured to generate a signal based on the output signal S out To determine the distance between the at least one electromagnetic actuator 178 and the ferromagnetic element 150 .

[0032] Figure 4 A magnetic levitation system 100 is shown with a vertically oriented carrier 110. The carrier 110 supports a substrate 120 oriented in a plane defined by a first direction 192 and a second direction 194. The first direction 192 is oriented substantially in the carrier transport direction. The second direction 194 is oriented substantially parallel to the direction of gravity. In particular, the first direction 192 is oriented substantially perpendicular to the second direction 194. However, the embodiments described herein are not limited to vertically oriented carriers. Other orientations of the carrier, such as a horizontal orientation, may also be provided.

[0033] In the present disclosure, the term "substantially parallel" directions may include directions that form a small angle of up to 10 degrees or even up to 15 degrees with each other. The term "substantially perpendicular" directions may include directions that form an angle of less than 90 degrees (e.g., at least 80 degrees or at least 75 degrees) with each other. Similar considerations apply to the concepts of substantially parallel or perpendicular axes, planes, areas, orientations, etc.

[0034] Some embodiments described herein relate to the concept of a "vertical direction". The vertical direction is considered to be a direction parallel or substantially parallel to the direction in which gravity extends. The vertical direction may deviate from the exact vertical (the latter being defined by gravity) by an angle of, for example, up to 15 degrees.

[0035] The embodiments described herein may further relate to the concept of a “horizontal direction”. The horizontal direction is to be understood as being distinguished from the vertical direction. The horizontal direction may be perpendicular or substantially perpendicular to the exact vertical direction defined by gravity.

[0036] Figure 4 The illustrated magnetic levitation system 100 includes a carrier 110. The carrier 110 supports a substrate 120. The carrier 110 includes a ferromagnetic element 150, such as a rod of a ferromagnetic material. The magnetic levitation system 100 includes a plurality of suspension units 170, which include electromagnetic actuators. In particular, the plurality of suspension units 170 include individual suspension units 175, which include at least one electromagnetic actuator 178. The plurality of suspension units 170 extend in a first direction 192. The carrier 110 is movable along the plurality of suspension units 170. The ferromagnetic element 150 and the plurality of suspension units 170 are configured to provide a magnetic levitation force to suspend the carrier 110. The magnetic levitation force extends in a second direction 194.

[0037] in addition, Figure 4 The illustrated magnetic levitation system 100 includes a magnetic drive structure 180. The magnetic drive structure 180 includes a plurality of magnetic drive units 185. The carrier 110 may include a second ferromagnetic element 160 to interact with the magnetic drive units 185 of the magnetic drive structure 180. The magnetic drive units 185 of the magnetic drive structure 180 drive the carrier within the processing system, for example, along a first direction 192. For example, the second ferromagnetic element 160 may include a plurality of permanent magnets arranged with alternating polarities. The magnetic field generated by the second ferromagnetic element 160 may interact with the plurality of magnetic drive units 185 of the magnetic drive structure 180 to move the carrier 110 in the first direction 192 while being suspended. Although Figure 4 An embodiment is shown in which the plurality of suspension units 170 are arranged at the top and the magnetic drive structure 180 is arranged at the bottom, it will be understood that, alternatively, the suspension units and the magnetic drive structure may be arranged on the same side. For example, both the plurality of suspension units 170 and the magnetic drive structure 180 may be arranged at the bottom or at the top. In other words, the magnetic levitation system 100 may be configured so that both the plurality of suspension units 170 and the magnetic drive structure 180 are disposed above or below the carrier 110 to be transported.

[0038] In addition, if Figure 4As exemplarily shown, the magnetic levitation system 100 may include a control unit 130. The control unit 130 may be connected to the plurality of levitation units 170. The control unit 130 may be configured for controlling the magnetic levitation of the carrier 110. The control unit 130 may be configured for controlling the distance between the carrier 110 and the plurality of levitation units 170 during levitation of the carrier 110, for example based on a measured distance supplied to the control unit 130 by a signal evaluation unit 145. Therefore, it will be understood that the signal evaluation unit 145 may be connected to the control unit 130 or be a part of the control unit 130. The magnetic drive structure 180 may drive the carrier 110 under the control of the control unit 130.

[0039] Embodiments described herein relate to magnetic levitation and / or transportation of a carrier (e.g., a substrate carrier). Thus, the magnetic levitation of the carrier can be contactless. The term "contactless" as used throughout the present disclosure can be understood in the following sense: the weight of the carrier is not maintained by mechanical contact or mechanical force, but by magnetic force. Specifically, magnetic force rather than mechanical force can be used to maintain the substrate carrier in a suspended or floating state. In some embodiments, there may be no mechanical contact at all between the carrier and the rest of the device during suspension of the carrier in a vacuum system and, for example, during movement.

[0040] An advantage over mechanical means for guiding a carrier in a processing system is that non-contact levitation does not suffer from friction that affects the linearity and / or precision of the carrier's movement. Non-contact transport of the carrier allows for frictionless motion of the carrier, wherein the position of the carrier, e.g., the position of the carrier relative to a mask in a deposition process, can be controlled and maintained with high precision. Additionally, levitation allows for rapid acceleration or deceleration of the carrier and / or fine adjustment of the carrier's speed.

[0041] For example, non-contact levitation or transport of the carrier during the deposition process is beneficial because during the transport of the carrier, there are no particles generated by mechanical contact between the carrier and sections of the equipment (such as mechanical rails). Therefore, the non-contact magnetic levitation system provides improved purity and uniformity of the layer deposited on the substrate, especially because particle generation is minimized when using non-contact magnetic levitation.

[0042] The magnetic levitation system may be configured to operate in a vacuum environment. The processing system may include at least one vacuum chamber, wherein a deposition process is performed on a substrate. The at least one vacuum chamber may include one or more vacuum pumps, such as turbo pumps and / or cryopumps, connected to the vacuum chamber to create a vacuum within the vacuum chamber. The magnetic levitation system may be configured to transport a substrate into, out of, or through the vacuum chamber.

[0043] The magnetic levitation system may be used to transport the carrier. The carrier may be adapted to carry a substrate, a plurality of substrates and / or a mask. The carrier may be a substrate carrier, for example, adapted to carry a large area substrate and / or a plurality of large area substrates. Alternatively, the carrier may be a mask carrier, for example, adapted to carry an edge exclusion mask for preventing the edges of the substrate from being coated during a deposition process.

[0044] The carrier according to the embodiments described herein is not necessarily limited to a substrate carrier or a mask carrier. The methods described herein are also applicable to other types of carriers, ie carriers suitable for carrying objects or devices other than, for example, a substrate or a mask.

[0045] The term "substrate" as used herein encompasses non-flexible substrates (e.g., glass substrates, wafers, slices or glass plates of transparent crystals such as sapphire, etc.) and flexible substrates (such as rolls or foils). According to embodiments that can be combined with other embodiments described herein, the embodiments described herein can be used for display PVD, i.e., sputter deposition on large area substrates for the display market.

[0046] According to embodiments, the large-area substrate or the corresponding carrier may have a surface area of ​​at least 0.67 m 2 The size can be from about 0.67m 2 (0.73m×0.92m, 4.5th generation) to about 8m 2 , more specifically about 2m 2 About 9m 2 , or even up to 12m 2 For example, the large area substrate or carrier may be of Generation 4.5 (which corresponds to approximately 0.67 m 2 substrate (0.73m×0.92m)), the 5th generation (which corresponds to about 1.4m 2 Substrate (1.1m×1.3m)), 7.5th generation (which corresponds to about 4.29m 2 Substrate (1.95m×2.2m)), 8.5th generation (which corresponds to about 5.7m 2 substrate (2.2m×2.5m)) or even the 10th generation (which corresponds to about 8.7m 2 Substrate (2.85m×3.05m)). Even higher generations (such as 11th and 12th generations) and corresponding substrate areas can be similarly realized.

[0047] For example, reference Figure 5 , describes a substrate processing system 200 according to the present disclosure. The substrate processing system 200 includes a magnetic levitation system 100 according to the embodiments described herein. In particular, the substrate processing system can be a vacuum system. Typically, the substrate processing system is configured to deposit one or more layers of, for example, organic material on a substrate 10.

[0048] like Figure 5 As shown exemplarily, typically, the substrate processing system 200 includes a vacuum chamber 202 (particularly a vacuum deposition chamber), a carrier 110 as described herein, and a magnetic levitation system 100 according to any embodiment described herein. The magnetic levitation system 100 is configured to transport the carrier 110 in the vacuum chamber 202. In addition, typically, the substrate processing system 200 includes one or more material deposition sources 210 in the vacuum deposition chamber. The carrier 110 may be configured to hold the substrate 10 during a deposition process (such as a vacuum deposition process). The substrate processing system 200 may be configured to evaporate materials (e.g., organic materials) (particularly for manufacturing OLED devices). In another example, the substrate processing system 200 may be configured for chemical vapor deposition CVD or physical vapor deposition PVD, such as sputtering deposition. Therefore, it will be understood that the embodiments described herein can also be used in the production of semiconductor devices.

[0049] In some embodiments, one or more material deposition sources 210 may be evaporation sources, particularly evaporation sources for depositing one or more organic materials on a substrate to form layers of an OLED device. Alternatively, one or more material deposition sources 210 may be CVD or PVD deposition sources.

[0050] For example, reference Figure 5 It will be appreciated that a carrier 110 for supporting a substrate 10, for example during a layer deposition process, may be transported into and through a vacuum deposition chamber along a transport path, and in particular through a deposition area. Typically, the transport path is a linear transport path. In addition, it will be appreciated that the material to be deposited may be emitted from one or more material deposition sources 210 in an emission direction toward a deposition area where the substrate 10 to be coated is located. For example, the one or more material deposition sources 210 may provide a line source having a plurality of openings and / or nozzles, the plurality of openings and / or nozzles being arranged in at least one line along the length of the one or more material deposition sources 210. The material to be deposited may be ejected through the plurality of openings and / or nozzles.

[0051] like Figure 5 As indicated, a further chamber 203, in particular a further vacuum chamber, may be arranged adjacent to the vacuum chamber 202, in particular a vacuum deposition chamber. The vacuum chamber 202 may be separated from the adjacent further chamber 203 by a valve having a valve housing 204 and a valve unit 206. After the carrier 110 with the substrate 10 thereon is inserted into the vacuum chamber 202 as indicated by the arrow, the valve unit 206 may be closed. The atmosphere in the vacuum chamber 202 may be controlled separately by generating a technical vacuum, for example by means of a vacuum pump connected to the vacuum chamber 202.

[0052] According to some embodiments, which can be combined with other embodiments described herein, the carrier 110, the substrate 10 and the optional mask 20 are static or dynamic during material deposition. For example, a dynamic deposition process may be provided, for example, for manufacturing OLED devices.

[0053] In addition, exemplarily referring to Figure 5 It will be appreciated that the substrate processing system 200 typically includes one or more transport paths extending through the vacuum chamber 202. The carrier 110 may be configured for transport along the one or more transport paths, for example, past one or more material deposition sources 210. Figure 5 In the figure, one transport path is exemplarily indicated by an arrow, but it will be understood that the present disclosure is not limited thereto, and two or more transport paths may be provided. For example, at least two transport paths may be arranged substantially parallel to each other for transporting corresponding carriers. One or more material deposition sources 210 may be arranged between the two transport paths.

[0054] For example, reference Figure 6 , which describes a method 300 for measuring a distance X between at least one electromagnetic actuator 178 and a ferromagnetic element 150 according to the present disclosure. According to an embodiment that can be combined with other embodiments described herein, the method includes measuring an inductance (given by Figure 6 The step of measuring the inductance includes measuring one or more output signals S out (Depend on Figure 6 320 in FIG. 1 ). One or more output signals are provided by one or more secondary windings 142 of one or more transformers 140. One or more transformers 140 are located in a current supply system 135 for supplying current to at least one electromagnetic actuator 178.

[0055] According to embodiments that can be combined with other embodiments described herein, such as reference Figure 2 As exemplarily described, the one or more transformers 140 include a first transformer 140A and a second transformer 140B. Thus, the step of measuring one or more output signals may include measuring a first output signal S provided by a first secondary winding 142A of the first transformer 140A. out1 In addition, the step of measuring one or more output signals may include measuring a second output signal S provided by the second secondary winding 142B of the second transformer 140B. out2 .

[0056] According to an embodiment which can be combined with other embodiments described herein, the method further comprises: test Added to one or more output signals (by Figure 6330 in FIG.

[0057] Will understand, refer to Figures 1 to 6 The features of the described magnetic levitation system 100 may also be applied to embodiments of the method for measuring the distance x between at least one electromagnetic actuator 178 and a ferromagnetic element 150 .

[0058] Figure 7 A diagram is shown for illustrating a voltage applied to at least one electromagnetic actuator and a voltage supplied to a transformer as a function of time, wherein U ACT is the voltage applied to at least one electromagnetic actuator, U TRANS is the voltage supplied to the transformer, and t represents the time. 1 and -U 1 represents an exemplary value of the voltage supplied to the transformer. For example, U 1 It can be 30V<U 1 <60V, for example, U 1 =48V±5V. Figure 7 The solid line in represents the voltage applied to at least one electromagnetic actuator over time. Figure 7 An exemplary test signal S is shown test and an exemplary voltage U applied to the at least one electromagnetic actuator to provide a force generating current in the at least one electromagnetic actuator c The dotted line represents the test signal S test The first output voltage signal S generated and provided on the first secondary winding 142A out1 The dotted line represents the test signal S test The second output voltage signal S generated and provided on the second secondary winding 142B out2 T represents the sampling time, in particular the sampling time of the signal evaluation unit 145 .

[0059] According to another aspect of the present disclosure, a method for manufacturing a coated substrate is provided. In particular, the coated substrate can be used to manufacture an electronic device, in particular an optoelectronic device. The method for manufacturing a coated substrate (in particular an electronic device) comprises using a magnetic levitation system according to any embodiment of the present disclosure. More specifically, the method for manufacturing a coated substrate (in particular an electronic device) may comprise using a substrate processing system as described herein.

[0060] In view of the embodiments of the present disclosure, it will be appreciated that, compared to the prior art, an improved magnetic levitation system, an improved substrate processing system and an improved method of measuring the distance between at least one electromagnetic actuator and a ferromagnetic element are provided. In particular, the embodiments of the present disclosure are improved in terms of the possibility of measuring the distance between the electromagnetic actuator and the ferromagnetic element. More specifically, the embodiments of the present disclosure provide a system with a self-inductive magnetic bearing, in particular a self-inductive electromagnetic actuator, so that an additional separate sensor for position or distance measurement can be omitted.

[0061] With regard to self-sensing magnetic bearings, it is noted that it is highly important that the magnetic bearing system can measure the position of a suspended part (e.g. a shaft of a rotating magnetic bearing system or a carrier of a magnetic levitation system). Typically, a separate position sensor is used to determine the position of the carrier. Providing a separate position sensor results in additional cost and effort. However, it is noted that changes in the carrier position will change the inductance of the electromagnetic actuator of the magnetic bearing. Therefore, in theory, the carrier position can be determined by measuring the inductance of the actuator.

[0062] Basically, there is a relationship between the voltage, inductance, and current of the actuator: dI / dt=U(t) / L, where I is the current of the electromagnetic actuator, U is the voltage applied to the electromagnetic actuator, and L is the inductance of the electromagnetic actuator. Therefore, the inductance of the actuator can be determined by measuring the voltage and current changes in the electromagnetic actuator. In the past, there were many methods for measuring the inductance of the actuator, which either required high-bandwidth and high-accuracy current measurement and a powerful computing platform, or used modulation / demodulation methods with high-frequency test signals, both of which are expensive and have limited performance.

[0063] As described herein, embodiments of the present disclosure advantageously include one or more transformers disposed in the current loop of the electromagnetic actuator, such that the measurement of current changes is greatly simplified. In particular, the measurement of current changes is simplified because the transformer is able to provide an output voltage on the secondary side that is proportional to the current change on the primary side. Thus, in contrast to conventional methods, high-speed current measurement and curve fitting to determine dI / dt are no longer required in the embodiments described herein. Additionally, it is noted that by adding transformers to the positive and negative paths of the electromagnetic actuator (as described in reference to FIG. 1 ), the measurement of current changes is greatly simplified. Figure 2 As exemplarily described), and by adding the output signal S out1 and S out2 (output voltage), which removes the static offset in the current to obtain a better signal.

[0064] Therefore, compared with the prior art, the advantages of the embodiments of the present disclosure are that it is convenient to provide distance measurement. In particular, the embodiments of the present disclosure are advantageously configured to provide an output signal that can be more easily processed and evaluated to determine the distance and / or position information of the ferromagnetic element relative to the electromagnetic actuator.

[0065] In other words, embodiments as described herein provide a magnetic levitation system having a self-sensing magnetic bearing configured to measure the distance between an electromagnetic actuator and a carrier. Thus, the magnetic levitation system can operate without a separate position sensor. Specifically, according to embodiments of the present disclosure, the electromagnetic actuator is used to determine the position of the carrier, i.e., the distance between the electromagnetic actuator and the ferromagnetic element of the carrier. Typically, the magnetic levitation system is a linear magnetic levitation system for carrier transportation. The carrier may be a substrate carrier configured to carry one or more substrates. Alternatively, the carrier may be a mask carrier configured to carry one or more masks.

[0066] As described herein, a transformer is added to the current loop of the electromagnetic actuator. In addition, a test signal of a specific shape can be added to the output voltage of the power amplifier. The output signal of the transformer can be fed into the circuit for signal conditioning. The output signal can be evaluated by a software algorithm to determine the carrier position, i.e., the distance between the carrier and the electromagnetic actuator.

[0067] Therefore, an advantage of embodiments of the present disclosure is that the need for a separate position sensor for controlling the magnetic levitation system is removed. Therefore, embodiments of the present disclosure advantageously provide for saving installation space, wiring work and costs. In addition, there is no need to install the electronics, in particular the sensors, in a vacuum housing, for example, of the magnetic levitation system.

[0068] In addition, an advantage of embodiments of the present disclosure is that a specific test signal can be added to the output voltage of an amplifier, in particular as described herein, enabling a simpler signal analysis to determine the carrier position than by measuring the current directly. Thus, it will be appreciated that embodiments of the present disclosure provide for utilizing a transformer in the current loop of an electromagnetic actuator in conjunction with a specific test signal and signal conditioning in order to measure the carrier position, in particular in the vertical direction. Advantageously, for the embodiments described herein, the test signal can be simple, such that no demodulation is required.

[0069] Conventional methods for position detection using electromagnetic actuators use ultrafast and high-resolution current measurements. Additionally, complex, model-based observers are typically required to determine position information from magnetic bearing actuators from high-bandwidth and high-resolution current measurements. In contrast, embodiments as described herein provide a simpler and more robust method for determining carrier position.

[0070] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the described subject matter, including making and using any device or system and performing any covered method. Although various specific embodiments have been disclosed in the above, non-mutually exclusive features of the embodiments described above may be combined with each other. The scope of patent protection is defined by the claims, and as long as other examples have structural elements that do not differ from the literal language of the claims, or as long as other examples include equivalent structures that are not substantially different from the literal language of the claims, then these examples are also expected to fall within the scope of the claims.

[0071] While the foregoing is directed to embodiments, other and further embodiments may be envisaged without departing from the basic scope, and the scope is determined by the claims that follow.

Claims

1. A magnetic suspension system (100) for a magnetically suspended ferromagnetic element (150), the magnetic suspension system comprising at least one electromagnetic actuator (178), the at least one electromagnetic actuator (178) being inductively coupled to one or more transformers (140) arranged in a current supply system (135), the current supply system (135) being used to supply current to the at least one electromagnetic actuator (178), The one or more transformers (140) are configured to provide one or more output signals for determining a distance between the at least one electromagnetic actuator (178) and the ferromagnetic element (150).

2. The magnetic levitation system (100) of claim 1, wherein the one or more transformers (140) have electrical connections (144) for providing the one or more output signals of the one or more transformers (140).

3. The magnetic levitation system (100) of claim 2, wherein the one or more transformers (140) have a primary winding (141) electrically connected to the current supply system (135) and a secondary winding (142) inductively coupled to the primary winding (141), and the electrical connection (144) is electrically connected to the secondary winding (142).

4. The magnetic levitation system (100) according to any one of claims 1 to 3, wherein the at least one electromagnetic actuator (178) comprises a coil (178A) and at least one ferromagnetic core (178B), and the coil (178A) is electrically connected to the current supply system (135).

5. A magnetic levitation system (100) as described in any one of claims 1 to 3, wherein the current supply system (135) includes a first circuit (135A) for conducting current from a power supply (131) to the at least one electromagnetic actuator (178) and a second circuit (135B) for conducting current from the at least one electromagnetic actuator (178) to the power supply (131), and the one or more transformers (140) are arranged in at least one of the first circuit (135A) and the second circuit (135B).

6. The magnetic levitation system (100) as described in claim 4, wherein the current supply system (135) includes a first circuit (135A) for conducting current from a power supply (131) to the at least one electromagnetic actuator (178) and a second circuit (135B) for conducting current from the at least one electromagnetic actuator (178) to the power supply (131), and the one or more transformers (140) are arranged in at least one of the first circuit (135A) and the second circuit (135B).

7. The magnetic levitation system (100) of claim 5, wherein the one or more transformers (140) include a first transformer (140A) and a second transformer (140B), the first transformer (140A) having a first primary winding (141A) electrically connected to the first circuit (135A), and the second transformer (140B) having a second primary winding (141B) electrically connected to the second circuit (135B).

8. The magnetic levitation system (100) according to any one of claims 1 to 3, wherein the current supply system (135) further comprises an amplifier (132) and a test signal unit (133), wherein the test signal unit (133) is configured to add a test signal to the output of the amplifier (132).

9. The magnetic levitation system (100) of claim 4, wherein the current supply system (135) further comprises an amplifier (132) and a test signal unit (133), wherein the test signal unit (133) is configured to add a test signal to an output of the amplifier (132).

10. The magnetic levitation system (100) of claim 5, wherein the current supply system (135) further comprises an amplifier (132) and a test signal unit (133), wherein the test signal unit (133) is configured to add a test signal to an output of the amplifier (132).

11. The magnetic levitation system (100) as described in claim 2 or 3 further includes a signal evaluation unit (145) connected to the electrical connection (144), and the signal evaluation unit (145) is constructed to determine the distance between the at least one electromagnetic actuator (178) and the ferromagnetic element (150) based on the one or more output signals of the one or more transformers (140).

12. The magnetic levitation system (100) of claim 4, further comprising a signal evaluation unit (145) connected to the electrical connection (144), the signal evaluation unit (145) being constructed to determine the distance between the at least one electromagnetic actuator (178) and the ferromagnetic element (150) based on the one or more output signals of the one or more transformers (140).

13. The magnetic levitation system (100) of claim 11, the signal evaluation unit (145) comprising an analog-to-digital converter.

14. A magnetic suspension system (100) for magnetically suspending a ferromagnetic element (150), comprising: - at least one electromagnetic actuator (178); - one or more transformers (140); - a current supply system (135); and - a signal evaluation unit (145), The at least one electromagnetic actuator (178) is electrically coupled to the one or more transformers (140) disposed in the current supply system (135), the current supply system (135) being configured to supply current to the at least one electromagnetic actuator (178), the one or more transformers (140) having a secondary winding (142) configured to provide an output signal to the signal evaluation unit (145), the signal evaluation unit (145) being configured to determine a distance between the at least one electromagnetic actuator (178) and the ferromagnetic element (150) based on the output signal.

15. A substrate processing system (200), comprising the magnetic levitation system according to any one of claims 1 to 14.

16. A method for measuring the distance between at least one electromagnetic actuator (178) and a ferromagnetic element (150), the method comprising measuring the inductance of the at least one electromagnetic actuator (178), wherein the step of measuring the inductance comprises measuring one or more output signals provided by one or more secondary windings (142) of one or more transformers (140) arranged in a current supply system (135), the current supply system (135) being used to supply current to the at least one electromagnetic actuator (178).

17. A method as claimed in claim 16, wherein the one or more transformers (140) include a first transformer (140A) and a second transformer (140B), and wherein the step of measuring the one or more output signals includes measuring a first output signal provided by a first secondary winding (142A) of the first transformer (140A) and measuring a second output signal provided by a second secondary winding (142B) of the second transformer (140B).

18. The method of claim 16 or 17, further comprising: A test signal is added to the one or more output signals.

19. A method of manufacturing a coated substrate comprising using a magnetic levitation system according to any one of claims 1 to 14.

20. A method of manufacturing an electronic device using a coated substrate manufactured using the method according to claim 19.

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