Magnetic suspension system, base and carrier of magnetic suspension system and method for suspending carrier

Abstract

A magnetic levitation system (100) for transporting a carrier (10) is described. The magnetic levitation system comprises: a base (20) defining a transport track; a carrier (10) movable relative to the base (20) along the transport track; and a plurality of active magnetic bearings (30) disposed at the base (20) and configured to face the guide structure (12) of the carrier. The guide structure (12) comprises a first guide region (13) and a second guide region (14) configured to interact with the plurality of active magnetic bearings (30), and a recessed region (15). The recess region (15) is arranged between the first guide region (13) and the second guide region (14) in the transport direction (T) of the carrier and is recessed relative to the first guide region (13) and the second guide region (14).

Description

[0001] This application is a divisional application of the invention patent application with the application date of April 29, 2019, application number 201980095601.6, and invention name "Magnetic levitation system, base and carrier of magnetic levitation system, and method of suspending carrier". Technical Field

[0002] Embodiments of the present disclosure relate to systems and methods for transporting carriers, particularly carriers for carrying large area substrates. More specifically, embodiments of the present disclosure relate to magnetic levitation systems for suspending and transporting carriers, particularly in vacuum chambers. In particular, embodiments of the present disclosure relate to magnetic levitation systems for transporting carriers, carriers of magnetic levitation systems, bases of magnetic levitation systems, and methods of suspending carriers. Background Art

[0003] Techniques for layer deposition on substrates include, for example, sputtering deposition, physical vapor deposition (PVD), chemical vapor deposition (CVD), and thermal evaporation. Coated substrates can be used in several applications and in several technical fields. For example, coated substrates can be used in the field of display devices. Display devices can be used to manufacture television screens, computer displays, mobile phones, other handheld devices, etc. to display information. Typically, displays are produced by coating substrates with layer stacks of different materials.

[0004] The substrate is typically coated in a vacuum deposition system that may include multiple deposition sources and other substrate processing equipment. The substrate is typically transported through the vacuum deposition system along a transport track, such as from a first deposition source to a second deposition source and to other substrate processing equipment. The substrate can be transported through the processing system in a substantially vertical orientation.

[0005] Typically, the substrate is carried by a carrier, i.e., a carrying device for carrying the substrate. Typically, the carrier is transported through the vacuum system using a carrier transport system (e.g., a magnetic levitation system in which the weight of the carrier is maintained by magnetic force). The carrier transport system can be configured to transport the carrier carrying the substrate along a base structure defining a transport track.

[0006] Accurately and smoothly transporting carriers through vacuum systems is challenging. For example, particle generation due to friction between moving parts can lead to degradation of the manufacturing process. Transporting carriers using a magnetic levitation system can reduce particle generation because mechanical contact between moving parts is reduced. For example, a magnetic levitation system can include a base with a plurality of actively controlled magnetic bearings that generate a magnetic levitation force to hold the carrier at the base in a non-contact or substantially non-contact manner. However, since tolerance requirements increase with the size of the object to be transported, it is difficult to transport large-area carriers having a size of several square meters using a magnetic levitation system.

[0007] Therefore, it would be beneficial to provide an improved magnetic levitation system for suspending and transporting a carrier in a vacuum system and an improved method for suspending a carrier in a vacuum system that overcomes at least some of the problems of the prior art. In particular, it would be beneficial to provide a magnetic levitation system for transporting a carrier carrying a large area substrate. Summary of the invention

[0008] In view of the above, a magnetic levitation system for transporting a vehicle, a vehicle of a magnetic levitation system, a base of a magnetic levitation system and a method of levitating a vehicle are provided.Further aspects, advantages and features are apparent from the dependent claims, the description and the drawings.

[0009] According to one aspect of the present disclosure, a magnetic levitation system for transporting a carrier is provided. The magnetic levitation system includes: a carrier that defines a transport track; a carrier that is movable along the transport track; and a plurality of active magnetic bearings that are arranged at the base and are configured as a guide structure facing the carrier. The guide structure of the carrier includes a first guide area, a second guide area, and a recessed area arranged between the first guide area and the second guide area in the transport direction of the carrier. The first guide area and the second guide area are configured to interact with the plurality of active magnetic bearings, and the recessed area is recessed relative to the first guide area and the second guide area.

[0010] According to one aspect of the present disclosure, there is provided a carrier of a magnetic levitation system, the carrier being movable along a transport track defined by a base. The carrier comprises: a guide structure, the guide structure comprising a first guide area and a second guide area, and a recessed area, the first guide area and the second guide area being configured to interact magnetically with a plurality of active magnetic bearings arranged at the base, the recessed area being arranged between the first guide area and the second guide area in a transport direction of the carrier, and the recessed area being recessed relative to the first guide area and the second guide area.

[0011] According to one aspect of the present disclosure, there is provided a base for a magnetic levitation system, the base defining a transport track for a carrier. The base includes: a plurality of active magnetic bearings for generating a levitation force to hold the carrier; and one or more controllers for individually controlling the plurality of active magnetic bearings according to the position of the carrier along the transport track. The one or more controllers are configured to actively control a first subset of the plurality of active magnetic bearings facing one of a first guide area and a second guide area of ​​the carrier, and not actively control a second subset of the plurality of active magnetic bearings facing a recessed area of ​​the carrier arranged between the first guide area and the second guide area.

[0012] In other words, the one or more controllers may be configured to actively control a first subset of the plurality of active magnetic bearings facing two distal regions of the carrier, and not to actively control a second subset of the plurality of active magnetic bearings facing a recessed region of the carrier arranged between the two distal regions.

[0013] According to another aspect of the present disclosure, a method for suspending a carrier is provided, the carrier comprising a first guide area, a second guide area, and a recessed area between the first guide area and the second guide area in a transport direction of the carrier. The method comprises controlling a plurality of active magnetic bearings to suspend the carrier relative to a base, wherein a first subset of the plurality of active magnetic bearings facing one of the first guide area and the second guide area is actively controlled or opened, and a second subset of the plurality of active magnetic bearings facing the recessed area is not actively controlled or closed.

[0014] The carrier can be used to carry a large-area substrate, especially a substrate with a size of 1 m 2 or larger, especially 5m 2 or larger, more particularly 10m 2 The carrier may be configured to carry a substrate of a size of 100 mm or larger. The substrate carried by the carrier may be a large area substrate for display manufacturing. The carrier may be configured to carry the substrate in a substantially vertical orientation.

[0015] The magnetic levitation system may be configured for transporting the carrier through a vacuum deposition system having a deposition source to deposit a layer stack on the substrate carried by the carrier.

[0016] The magnetic levitation system may be configured for non-contact or substantially non-contact transportation of the carrier, such that particle generation due to frictional forces may be reduced or avoided.

[0017] Embodiments also relate to apparatus for performing the disclosed methods and include apparatus portions for performing each described method aspect. These method aspects may be performed by means of hardware components, computers programmed with 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 apparatus. The methods for operating the described apparatus include method aspects for performing each function of the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to understand the above-mentioned features of the present disclosure in detail, a more particular description of the present disclosure briefly summarized above may be obtained by reference to the embodiments. The accompanying drawings relate to the embodiments of the present disclosure and are described as follows:

[0019] Figure 1shows a front view of a magnetic levitation system according to an embodiment described herein, the magnetic levitation system comprising a base and a carrier according to an embodiment described herein;

[0020] Figure 2 shows a schematic perspective view of a magnetic levitation system according to an embodiment described herein;

[0021] Figure 3 Shows Figure 2 A cross-sectional view of a magnetic suspension system in a first section (A);

[0022] Figure 4 Shows Figure 2 A cross-sectional view of the magnetic levitation system in a second section (B); and

[0023] Figure 5 is a flow chart illustrating a method of suspending a carrier according to embodiments described herein. DETAILED DESCRIPTION

[0024] 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 single embodiment are described. Each example is provided in a manner to explain the present disclosure and is not intended to limit the present disclosure. In addition, features shown or described as parts of one embodiment may be used on other embodiments or in combination with other embodiments to produce yet another embodiment. The specification is intended to include such modifications and variations.

[0025] Figure 1 is a schematic diagram of a magnetic levitation system 100 according to embodiments described herein. The magnetic levitation system 100 comprises a base 20 defining a transport track and a carrier 10 movable along the transport track in a transport direction T, typically a substantially horizontal direction.

[0026] The magnetic levitation system 100 described herein can be a carrier transport system configured to hold and transport a carrier in a vacuum environment, in particular in a vacuum chamber or in a vacuum system comprising a plurality of vacuum chambers arranged close to each other, for example, in a linear array or a 2-dimensional array. Specifically, the magnetic levitation system 100 can be part of a vacuum processing system, in particular a vacuum deposition system configured to deposit a material on a substrate carried by a carrier.

[0027] As used herein, "carrier" may be understood as a carrying device configured to carry an object, in particular a substrate to be coated, through a vacuum environment. The carrier may include a carrier body and a holding device (e.g., mechanical, electrostatic or magnetic adsorption device) configured to hold the substrate at a supporting surface of the carrier body.

[0028] The carrier can be configured to carry a large area substrate, i.e. a substrate having a size of 1 m 2 or larger, especially 5m 2 or larger, more particularly 8m 2 or larger or even 10m 2 The carrier can be a large and heavy component, with the carrier body having a substrate support surface of several square meters. For example, the carrier can have a weight of 200 kg or more (e.g., from 400 kg to 2000 kg, such as 1000 kg or more) and / or a length of several meters. It is challenging to transport and hold large and heavy carriers using the levitation magnets of a magnetic levitation system.

[0029] As used herein, a "magnetic levitation system" may be understood as a carrier transport system configured to hold at least a portion of the weight of the carrier or the entire weight of the carrier by magnetic force. For example, the carrier may be held relative to a base in a non-contact manner or in a substantially non-contact manner during transportation along a transport track. The magnetic levitation system may include a plurality of levitation magnets for suspending the carrier relative to the base, for example active and / or passive levitation magnets, such as a plurality of active magnetic bearings.

[0030] The base is typically a fixed structure along which the carrier can move. In one embodiment, the base includes a rail or track structure in which the suspension magnets are arranged at regular intervals. For example, the base can extend from a first vacuum chamber to a second vacuum chamber, and the substrate can be loaded on the carrier in the first vacuum chamber, and a deposition source for coating the substrate is arranged in the second vacuum chamber. The carrier can typically be transported along the base using a drive unit (e.g., a linear motor).

[0031] like Figure 1 Schematically depicted, the magnetic levitation system 100 includes a plurality of active magnetic bearings 30 disposed at a base 20. Active magnetic bearings are actively controlled magnetic bearings. Actively controlled magnetic bearings are configured to maintain a carrier at a predetermined distance at a base by applying a magnetic force. For example, each active magnetic bearing may include an actuator having a controllable magnet (e.g., an electromagnet) disposed at a base, such as at a top rail of the base. The actuator may be actively controllable for maintaining a predetermined distance (or "gap G") between the base 20 and the carrier 10.

[0032] For example, output parameters (such as the current applied to the actuator) may be controlled based on input parameters (such as the distance between the carrier and the base). The distance between the base and the carrier may be measured with a distance sensor, and the magnetic field strength of the actuator may be set based on the measured distance. Specifically, the magnetic field strength may be increased at a distance above a predetermined threshold, and the magnetic field strength may be reduced at a distance below the threshold. The actuator may be controlled in a closed loop or feedback control manner.

[0033] Each of the plurality of active magnetic bearings 30 may include an actuator (e.g., an electromagnet) and a distance sensor. A controller may be provided for controlling the actuator according to the distance measured by the distance sensor. Each magnetic bearing may have a corresponding controller. Alternatively, a common controller may be provided for controlling a plurality of active magnetic bearings.

[0034] A plurality of active magnetic bearings 30 are configured to face the guide structure 12 of the carrier during transportation of the carrier along the transport track. The guide structure 12 of the carrier may include a magnetic component having an upwardly facing surface, which faces the plurality of active magnetic bearings 30. The magnetic component of the guide structure 12 may include a ferromagnetic material, for example an iron alloy such as steel. A controlled attractive force may be generated between the guide structure 12 of the carrier and at least some of the active magnetic bearings so that the carrier may be suspended. The guide structure 12 may be an upper portion of the carrier, which is configured to interact magnetically with the plurality of active magnetic bearings 30.

[0035] During transport of the carrier 10 in a floating state in the transport direction T, the plurality of active magnetic bearings 30 are typically controlled such that the distance (or “gap G”) between the base 20 and the carrier 10 remains substantially constant, for example in a range between 0.5 mm and 2 mm, such as about 1 mm or 1.5 mm.

[0036] However, if the carrier 10 is very long and very heavy, it is difficult to maintain a substantially constant gap over the entire length of the carrier 10. In this case, the guide structures of the base and the carrier need to be manufactured with very high precision and flatness, because surface flatness or changes in the curvature of the carrier beyond the allowed level will cause contact between the carrier and the base, or even make magnetic levitation of the carrier impossible. In addition, there is a risk that the base or the carrier may bend due to pressure or temperature changes in the vacuum system, so that maintaining a constant gap width through the control of the multiple active magnetic bearings may be difficult or impossible.

[0037] The embodiments described herein allow for magnetic levitation of long and heavy carriers. The guide structure 12 of the carrier 10 described herein comprises a first guide area 13 and a second guide area 14 configured to interact with a plurality of active magnetic bearings 30, and a recessed area 15 arranged between the first guide area 13 and the second guide area 14 in the transport direction T of the carrier (i.e. in the longitudinal direction of the carrier). The recessed area 15 is recessed relative to the first guide area 13 and the second guide area 14. For example, the recessed area 15 may be recessed by at least 2 mm or more, in particular 3 mm or more (mm) relative to the first guide area and the second guide area. Figure 1 In other words, the recessed area 15 may form a deepening or indentation in the guide structure 12 of the carrier, which is further away from the plurality of active magnetic bearings 30 than the first guide area 13 and the second guide area 14 during transport of the carrier.

[0038] During the carrier transport, only the first guide area 13 and the second guide area 14 can interact magnetically with the active controlled magnetic bearings of the plurality of active magnetic bearings 30. Specifically, the first gap between the first guide area 13 and the base 20 can be controlled to remain substantially constant, for example, in the range from G = 0.5 mm to G = 2 mm, and the second gap between the second guide area 14 and the base can be controlled to remain substantially constant, for example, in the range from G = 0.5 mm to G = 2 mm. The distance between the recessed area 15 and the base 20 is large, for example, 4 mm or more, in particular 5 mm or more, which corresponds to the sum of the gap G and the recessed depth X.

[0039] According to the embodiments described herein, there is no need to provide a single highly flat actuator surface of the base 20 and a single highly flat guide zone of the carrier 10. Instead, the active magnetic bearing interacts magnetically with two separate and distal zones of the carrier, namely with the first guide zone 13 and the second guide zone 14. The active magnetic bearing is controlled to keep the first guide zone and the second guide zone at a predetermined small distance from the base, respectively. Therefore, even if the carrier and / or the base bend due to temperature or pressure changes, there is no risk of contact between the guide structure 12 and the base 20, the distance between the recessed zone 15 and the base 20 being large enough to avoid any risk of contact during transport of the carrier. A smooth and reliable suspension of long carriers is possible.

[0040] In some embodiments that may be combined with other embodiments described herein, the first guide area 13 and the second guide area 14 define a first plane P1. In other words, the first guide area 13 and the second guide area 14 are substantially located in the same plane, and the first plane P1 has a first distance (corresponding to the gap G) from the plurality of active magnetic bearings 30 during transport of the carrier. For example, the guide structure 12 of the carrier may include a magnetic material component having a first upwardly facing surface in a front portion of the carrier, the first upwardly facing surface constituting the first guide area 13, and having a second upwardly facing surface in a rear portion of the carrier in the transport direction T, the second upwardly facing surface constituting the second guide area 14. During transport of the carrier, the first upwardly facing surface and the second upwardly facing surface may be substantially in the same plane, i.e., in the first plane P1.

[0041] In some embodiments, the recessed area 15 defines a second plane P2, which has a second distance greater than the first distance from the plurality of active magnetic bearings during carrier transport. The recessed area 15 may have an upwardly facing surface that is arranged between the first guide area and the second guide area and is recessed by at least the second distance relative to the first guide area and the second guide area. The recessed area 15 may have a substantially flat surface. In other embodiments, the recessed area 15 is not completely flat. However, it is beneficial that the recessed area 15 is recessed by a recessed depth X of at least 2 mm or at least 4 mm relative to both the first guide area 13 and the second guide area 14 over the entire extended length between the first guide area 13 and the second guide area 14, so that contact between the base and the carrier can be reliably avoided.

[0042] In some embodiments, the first distance (corresponding to the gap G) is 2 mm or less, in particular about 1.5 mm, and / or the second distance (corresponding to the sum G+X) is 3 mm or more, in particular about 5 mm. In other words, the second plane P2 may be recessed relative to the first plane P1 by at least 1 mm, in particular by a recessed depth X of 3 mm or more. Therefore, even if the recessed area 15 has some curvature or is uneven, when the gap G between the first guide area and the second guide area and the base is controlled to remain within a predetermined range of less than 2 mm, there is no risk of contact between the recessed area 15 and the base 20.

[0043] In some embodiments, the carrier has a substantially vertical orientation during carrier transport. In other words, the carrier can be oriented so that the main surface of the carrier is substantially vertical (vertical + / - 10°) during carrier transport. The guide structure 12 can constitute an upper portion of the carrier 10, which is configured to interact magnetically with multiple active magnetic bearings 30. During carrier transport, the top guide rail of the base 20 with multiple active magnetic bearings 30 can be arranged above the guide structure 12 of the carrier. The transport direction T can be a substantially horizontal direction. The transport direction T can correspond to the longitudinal direction of the carrier, along which the carrier moves.

[0044] In some embodiments that may be combined with other embodiments described herein, the carrier 10 has an upper carrier surface. During carrier transport, the upper carrier surface faces the plurality of active magnetic bearings 30. A front portion of the upper carrier surface in the transport direction T may constitute a first guide area 13, and a rear portion of the upper carrier surface in the transport direction T may constitute a second guide area 14. A space corresponding to the recessed area 15 located between the first guide area 13 and the second guide area 14 in the transport direction T may have a length of 1 m or more.

[0045] In the front and rear parts of the carrier, only the gap G between the carrier and the base may be actively controlled, while no active control of the gap may be provided in the central part of the carrier provided with the recessed area 15. Smooth and reliable carrier transport may be provided without the risk of control difficulties caused by varying gap widths.

[0046] In some embodiments that may be combined with other embodiments described herein, the first guide area 13 and the second guide area 14 have a size of 30 cm or more in the transport direction, and / or the recessed area 15 may have a size of 1 m or more, in particular 2 m or more, in the transport direction T. According to the embodiments described herein, active control of the gap between the carrier and the base at two different areas of the carrier is sufficient to provide reliable carrier suspension. Active control in the central area of ​​the carrier where the recessed area is arranged may not be required. In some specific implementations, the total length of the carrier in the transport direction may be 2 m or more, in particular 3 m or more. The recessed area 15 may extend in the transport direction over half of the length of the carrier.

[0047] In some embodiments, the magnetic levitation system may further include one or more controllers 50 for individually controlling the plurality of active magnetic bearings 30 based on the position of the carrier along the transport track.

[0048] Specifically, a position of a carrier along a transport track may be determined, and a plurality of active magnetic bearings may be controlled based on the position of the carrier.

[0049] For example, the one or more controllers 50 may be configured to actively control at least one magnetic bearing 31 of the plurality of active magnetic bearings 30 when the at least one magnetic bearing 31 faces one of the first guide area 13 and the second guide area 14. In other words, when it is determined that the carrier is at a carrier position along the transport track where the at least one magnetic bearing 31 faces the first guide area 13 or the second guide area 14, the at least one magnetic bearing 31 is actively controlled to maintain a constant gap G between the corresponding guide area and the base. Alternatively or additionally, the one or more controllers 50 may be configured to turn off active control of the at least one magnetic bearing 31 when the at least one magnetic bearing 31 faces the recessed area 15. In other words, when it is determined that the carrier is at a carrier position along the transport track where the at least one magnetic bearing 31 faces the recessed area 15, the at least one magnetic bearing 31 may not be actively controlled and / or may be turned off.

[0050] In some specific implementations, the plurality of active magnetic bearings 30 may be controlled so that a first subset of the plurality of active magnetic bearings facing one of the first guide area 13 and the second guide area 14 is actively controlled or opened, and a second subset of the plurality of active magnetic bearings facing the recessed area 15 is not actively controlled or closed. A third subset of the active magnetic bearings that does not face the guide structure 12 of the carrier at all may also not be actively controlled or may be closed.

[0051] Therefore, in some embodiments, only the active magnetic bearing facing the first guide area 13 or the second guide area 14 may be actively controlled, and the remaining magnetic bearings may be switched off, or the active control may be deactivated. Smooth and reliable carrier transport may be ensured.

[0052] A plurality of active magnetic bearings 30 may be distributed at constant intervals along the transport track defined by the base, wherein the interval between two adjacent active magnetic bearings may be smaller than the dimension of the first guide area 13 (and the second guide area 14) in the transport direction T. Therefore, it is ensured that at least one active magnetic bearing faces the first guide area 13 (and the second guide area 14) at any time during the movement of the carrier along the transport track. Typically, at least two active magnetic bearings face the first guide area 13 and at least two other active magnetic bearings face the second guide area 14 at any time during the movement of the carrier.

[0053] In some embodiments, which may be combined with other embodiments described herein, the magnetic levitation system further comprises a drive unit for moving the carrier 10 along the transport track. The drive unit may comprise a linear motor 60, which moves the carrier in the transport direction T by magnetic force. Figure 1 Schematically depicted, the linear motor 60 may optionally be arranged at a lower rail of a base arranged below the carrier.The linear motor 60 may interact with a magnetic counterpart arranged at a bottom portion of the carrier, for example, an array of permanent magnets arranged at the carrier.

[0054] In some implementations, the linear motor 60 may be configured to determine the position of the carrier along the transport track and send the carrier position to one or more controllers 50 of the plurality of active magnetic bearings 30. For example, the motor 60 may include a position detection device, such as an encoder or a resolver, which provides information about the current carrier position. Thus, one or more controllers 50 in the plurality of active magnetic bearings 30 know the current carrier position and may control the plurality of active magnetic bearings 30 based on the current carrier position along the transport track. Alternatively or additionally, a separate position detection device (e.g., a sensor, such as a distance sensor) may be provided to determine the presence of the carrier at a particular position along the base. The output of the sensor may be sent to one or more controllers of the plurality of active magnetic bearings.

[0055] Thus, the position of the carrier along the transport track can be determined, and information about the position of the carrier can be sent to one or more controllers of the plurality of active magnetic bearings. Thus, the plurality of active magnetic bearings can be controlled according to the current position of the carrier, and a subset of the plurality of active magnetic bearings facing the recessed area 15 can be temporarily shut down or deactivated.

[0056] According to another aspect described herein, a carrier 10 of a magnetic levitation system 100 is described. The carrier 10 is movable along a transport track defined by a base 20. A plurality of magnetic bearings for holding the carrier in a contactless or substantially contactless manner may be provided at the base. Figure 1 The carrier 10 according to embodiments described herein is shown during contactless transport along a base 20 .

[0057] The carrier includes a guide structure 12. The guide structure 12 may include a magnetic material component having an upwardly facing surface, which faces toward the magnetic bearing of the base during the transport of the carrier. The guide structure 12 includes a first guide area 13 and a second guide area 14 configured to interact magnetically with a plurality of active magnetic bearings 30, and a recessed area 15 arranged between the first guide area 13 and the second guide area 14 in the transport direction of the carrier T. The recessed area is recessed relative to the first guide area 13 and the second guide area 14, for example, the recessed depth X along the entire longitudinal extension length of the recessed area is at least 2 mm.

[0058] The carrier 10 may further include a holding device for holding the substrate 11 at a holding surface of the carrier. The substrate 11 may be a large-area substrate for display manufacturing, which has a size of, for example, several square meters. Alternatively, the substrate 11 may be a semiconductor wafer, or may include a plurality of wafers. The holding device may be a mechanical clamping device, for example, a clamp, an electrostatic chuck, or a magnetic chuck.

[0059] In particular, the substrate 11 may be at least 1 m in size. 2The size can be from about 1.375m 2 (1.1m×1.25m, 5th generation) to about 15m 2 , more specifically from about 5m 2 About 9m 2 or even up to 15m 2 For example, a large area substrate may correspond to about 4.39 m 2 The surface area of ​​the 7.5th generation (1.95m × 2.25m) corresponds to about 5.7m 2 The surface area of ​​​​(2.2m×2.5m) is 8.5 times the original surface area, or about 9m 2 (2.88 m x 3.13 m) of surface area. Even higher generations (such as 11th and 12th generations) are achievable. The carrier 10 has a substrate supporting surface for supporting and holding a substrate.

[0060] The dimension of the carrier 10 in the vertical direction V may be 1 m or more, in particular 2 m or more or even 3 m or more. The dimension of the carrier 10 in the longitudinal direction corresponding to the transport direction T may be 1 m or more, in particular 2 m or more or even 3 m or more. The carrier may have a 5 m 2 or larger, especially 9m 2 or larger or even 15m 2 or larger size.

[0061] A guide structure 12 configured to interact with the base 20 may be provided at an upper portion of the carrier. Alternatively or additionally, a bottom portion of the carrier 10 may be configured to interact with a linear motor 60 to move the carrier 10 along the transport track.

[0062] The guide structure 12 comprises at least three different areas, namely a first guide area 13, a recessed area 15 and a second guide area 14. The guide structure 12 may be constructed according to any of the embodiments described herein, so that reference may be made to the above description and no further description is given here.

[0063] According to another aspect described herein, a base 20 of a magnetic levitation system 100 is described, wherein the base defines a transport track for a carrier. The base includes a plurality of active magnetic bearings 30 for generating at least a portion of the levitation force to maintain the carrier in a floating state. The plurality of active magnetic bearings may optionally be arranged at a top rail of the base, i.e., above a guide structure 12 of the carrier during transport of the carrier. The base also includes one or more controllers 50 for individually controlling the plurality of active magnetic bearings 30 according to the position of the carrier along the transport track.

[0064] In some embodiments that may be combined with other embodiments described herein, one or more controllers 50 are configured to actively control a first subset of one of the first guide areas 13 and the second guide areas 14 of a plurality of active magnetic bearings facing the carrier, and to shut down active control of a second subset of the recessed areas 15 of the plurality of active magnetic bearings 30 facing the carrier and arranged between the first guide area 13 and the second guide area 14.

[0065] In other words, the one or more controllers 50 may be configured to control the plurality of active magnetic bearings 30 such that a first subset is actively controlled, and a second subset arranged between the actively controlled magnetic bearings of the first subset is not actively controlled, or is turned off. Thus, the carrier may be suspended by applying an actively controlled magnetic force on two distal regions of the carrier's guide structure while at least one active magnetic bearing arranged between the actively controlled magnetic bearings is not actively controlled.

[0066] Figure 2 2 shows a schematic perspective view of an upper portion of a magnetic levitation system 200 according to an embodiment described herein. The magnetic levitation system 200 is similar to Figure 1 The magnetic levitation system 100 can be referred to the above description and will not be described again here.

[0067] The magnetic levitation system 200 includes a base having a plurality of active magnetic bearings 30 arranged along a transport track, and a carrier 10 that can be levitated using the plurality of active magnetic bearings 30 . Figure 2 Only the upper front portion of the carrier 10 is depicted.

[0068] The plurality of active magnetic bearings 30 interact magnetically with the guide structure 12 on the carrier. The guide structure 12 may be arranged at the head portion of the carrier and may include a magnetic material (such as magnetic steel) having an upwardly facing surface. The guide structure 12 may be attracted toward the plurality of active magnetic bearings 30, wherein the plurality of active magnetic bearings are actively controlled so that a constant gap G is maintained between the carrier 10 and the base 20 (see Figure 3 ).

[0069] The guide structure 12 of the carrier includes a first guide area 13 , a recessed area 15 and a second guide area, wherein the recessed area 15 is arranged between the first guide area 13 and the second guide area in the transport direction T of the carrier. Figure 2 Only the upper front portion of the carrier without the second guide area is shown. The recessed area 15 may be recessed to a depth X of at least 2 mm or more relative to the first guide area and the second guide area, such as Figure 3 and Figure 4 Schematically indicated.

[0070] The first guide area and the second guide area may comprise a guide surface 17 which is flat and lies in the same plane, in particular in a substantially horizontal plane, during transport of the carrier. The guide surface 17 may extend in a transport direction T of the carrier so that the guide surface 17 may interact with a magnetic bearing of the plurality of active magnetic bearings. The guide surface 17 may be an upwardly facing surface of the carrier, in particular a top surface of the carrier.

[0071] Figure 3 Shows Figure 2 A schematic cross-sectional view of a magnetic suspension system 200 in a first section (A). The first section (A) is located at Figure 2 The first section (A) intersects the first guide area 13 .

[0072] Figure 4 Shows Figure 2 A schematic cross-sectional view of the magnetic suspension system 200 in the second section (B). The second section (B) is located at Figure 2 The second cross section (B) intersects the recessed area 15 .

[0073] like Figure 3 and Figure 4 Schematically indicated, the distance between the first guide area 13 (and the second guide area) and the base 20 corresponds to the actively controlled gap G and is smaller than the distance between the recessed area and the base by a recessed depth X of, for example, 2 mm or more.

[0074] In some embodiments, which may be combined with other embodiments described herein, a plurality of permanent magnets 18 configured to contribute to the carrier levitation force may be disposed at the recessed area 15 .

[0075] Even if the active control of the magnetic bearing is turned off, a magnetic attraction force may act between the permanent magnet 18 of the recessed area 15 and the magnetic bearing facing the permanent magnet among the plurality of active magnetic bearings 30. This is because the active magnetic bearing typically includes an actuator (e.g., an electromagnet) that includes a magnetic material component 19, such as an iron or steel core of the electromagnet. The permanent magnet 18 of the recessed area 15 may be attracted toward the magnetic material component 19 of the actuator, even if the actuator is not actively controlled, thereby causing a levitation force acting on the carrier.

[0076] In particular, a first (actively controlled) part of the suspension force of the suspended carrier may act between a first subset of the plurality of active magnetic bearings and the first and second guide zones, and a second (passive) part of the suspension force of the suspended carrier may act between the permanent magnet 18 and the magnetic material components 19 of the actuators when some of the actuators of the plurality of active magnetic bearings may not be actively controlled. The first part of the suspension force is actively controlled to maintain a constant gap G between the first subset of the plurality of active magnetic bearings and the first and second guide zones. Therefore, it may not be necessary for the entire weight of the carrier to be carried by the actively controlled magnetic bearings. Instead, at least a portion of the weight of the carrier may be carried by the mutual magnetic action between the passive element acting as a weight compensation element, i.e., the permanent magnet 18 and the magnetic material component 19 of the actuator (e.g., the iron core of the electromagnet).

[0077] In some implementations, a static current may be applied to the coil 16 surrounding the magnetic material component 19 in order to adapt the second part of the levitation force. For example, the second part of the levitation force may be adapted to the weight and size of the carrier and / or the substrate carried by the carrier. In particular, a static current may be applied to the coil 16 surrounding the actuator iron of the magnetic bearing in order to increase or decrease the magnetic field between the permanent magnet 18 and the magnetic material component 19.

[0078] In some specific implementations, the plurality of permanent magnets 18 may be arranged in two parallel traces at a distance corresponding to the distance between the magnetic material components 19 of the plurality of active magnetic bearings 30. For example, the active magnetic bearings may each include two actuator irons arranged at a distance corresponding to the distance between the two parallel traces, such as Figure 4 Schematically depicted. Since only a part of the carrier weight is carried by the actively controlled magnetic bearing, the carrier levitation may be facilitated. Two parallel tracks may be arranged adjacent to each other in a lateral direction L perpendicular to the transport direction T of the carrier.

[0079] In some embodiments, which may be combined with other embodiments described herein, the permanent magnets 18 may provide a lateral stabilization device, which stabilizes the carrier relative to the base 20 in a lateral direction L perpendicular to the transport direction T. In particular, the permanent magnets 18 may be arranged so that when the carrier moves in the lateral direction L from the base 20 Figure 4 The depicted equilibrium position exerts a restoring force on the carrier in the event of a displacement. In the equilibrium position of the carrier, the permanent magnets 18 of the carrier are arranged below the magnetic material component 19 of the magnetic bearing. Thus, the permanent magnets 18 can contribute to both the carrier levitation force and a stable carrier position in the lateral direction L.

[0080] Specifically, according to some implementations, the permanent magnets 18 may be arranged at a lateral distance matching the width of the actuator of the active magnetic bearing, so that a lateral position deviation of the carrier will generate a restoring force towards the center position.

[0081] In the following, some of the advantageous effects provided by the embodiments described herein will be summarized. According to the embodiments described herein, only the magnetic bearings arranged above the front section and above the rear section of the carrier in the transport direction can be actively controlled, while the active control of at least some magnetic bearings arranged between the actively controlled magnetic bearings can be temporarily turned off. Active control only at the front section and the rear section of the carrier reduces the risk of exciting vibrations of the carrier, because the vibration eigenmodes of the carrier typically have large vibration amplitudes at the center of the carrier where no active control is applied.

[0082] In some embodiments, carrier vibrations may induce currents in the coils 16 of the active magnetic bearings facing the recessed areas 15. Thus, the coils 16 may be used as active dampers to damp carrier vibrations by adjusting the coil currents accordingly. In some implementations, a first subset of the first and second guide areas of the plurality of active magnetic bearings 30 facing the carrier is used to control the width of the gap G, and thereby the vertical carrier position. Optionally, a second subset of the recessed areas 15 of the plurality of active magnetic bearings facing the carrier may be used as a tunable damper for damping carrier vibrations and / or for carrying at least a portion of the weight of the carrier.

[0083] The carrier deformation due to thermal and / or pressure changes is typically strongest in the center of the carrier. According to the embodiments described herein, the gap between the carrier and the base in the center region of the carrier may not be actively controlled. Therefore, carrier deformation is less problematic in terms of active control of the magnetic bearing. That is, two distal gaps in the front and rear sections of the carrier, where carrier deformation is typically less pronounced, may be actively controlled according to the embodiments described herein.

[0084] According to some embodiments described herein, an actively controlled magnetic bearing may carry only a portion of the weight of the carrier, while another portion of the weight of the carrier may be carried by a passive magnetic unit on a central section that may act on the carrier. Thus, a smaller active magnetic unit may be used, and the actuator iron of the active magnetic bearing may interact with a permanent magnet 18 arranged at the recessed area 15, which acts as a weight compensation magnet.

[0085] Figure 5 is a flow chart illustrating a method of suspending a carrier according to an embodiment described herein.The carrier comprises a first guide area 13, a second guide area 14 and a recessed area 15 located between the first guide area 13 and the second guide area 14 in a transport direction T of the carrier.

[0086] In block 510, the plurality of active magnetic bearings 30 are controlled to suspend the carrier 10 relative to the base 20. A first subset of the plurality of active magnetic bearings facing one of the first guide area 13 and the second guide area 14 is actively controlled, or turned on, and a second subset of the plurality of active magnetic bearings facing the recessed area 15 is not actively controlled, or turned off. "Active control" of magnetic bearings as used herein involves actively controlling the magnetic bearings according to a measured width of the gap between the carrier and the base to maintain a constant gap width, i.e., to maintain a predetermined vertical carrier positioning relative to the base.

[0087] A first subset of the plurality of active magnetic bearings may be controlled such that a first gap between the first guide region 13 and the base and a second gap between the second guide region 14 and the base remain substantially constant.

[0088] In (optional) block 520, the method may further include transporting the carrier 10 along a transport track defined by the base 20. During transport of the carrier, the position of the carrier along the transport track is repeatedly determined, and the plurality of active magnetic bearings may be controlled based on the carrier position.

[0089] Specifically, according to the current carrier position, the magnetic bearings in the plurality of active magnetic bearings 30 can be allocated to the first subset (and therefore, the first subset is actively controlled) and / or the second subset (and therefore, the second subset is not actively controlled or turned off). Therefore, during the carrier transportation, the active magnetic bearings facing one of the first guide area and the second guide area are actively controlled, while the active magnetic bearings facing the recessed area are not actively controlled or turned off.

[0090] In some embodiments, a first portion of the levitation force of the levitation carrier acts between a first subset of the plurality of active magnetic bearings and the first guide area and the second guide area. A second portion of the levitation force of the levitation carrier may act between a second subset of the plurality of active magnetic bearings and a plurality of permanent magnets 18 disposed at the recessed area 15. The second portion of the levitation force may be generated by a passive unit that is not actively controlled based on the measured gap width.

[0091] In particular, a first portion of the suspension force is varied by one or more controllers to maintain a constant distance between a first subset of the plurality of active magnetic bearings and the first and second guide regions, while a second portion of the suspension force may be generated by a passive unit (e.g., a permanent magnet).

[0092] In (optional) block 530, the carrier carrying the large area substrate is transported to a vacuum deposition chamber, and one or more materials are deposited on the substrate in the vacuum deposition chamber. During deposition, the carrier may not be suspended, but may be held on a mechanical mounting device. After deposition, the carrier may be transported outside the vacuum deposition chamber in a floating state by a magnetic levitation system.

[0093] The embodiments described herein may be used to transport a carrier carrying at least one of a large area substrate, a glass substrate, a wafer, a semiconductor substrate, a mask, a shield, and other objects. The carrier may carry a single object, such as a 1 m 2 or larger, especially 5m 2 or 10m 2 The carrier may be used to carry a large-area substrate of a size of 1000 or larger, or may carry a plurality of objects of a smaller size (e.g., a plurality of semiconductor wafers). The carrier may include a holding device configured to hold the object at the carrier, such as a magnetic chuck, an electrostatic chuck, or a mechanical chuck device.

[0094] The carrier may have a substantially vertical orientation during transport (eg, vertical + / - 10°). Alternatively, the carrier may have a substantially horizontal orientation during transport (eg, horizontal + / - 10°). Specifically, the vacuum deposition system may be configured for vertical substrate transport and processing.

[0095] While the foregoing is directed to embodiments, other and further embodiments may be envisaged without departing from the basic scope, and the scope is to be determined by the scope of the appended claims.

Claims

1. A magnetic suspension system (100) for transporting a carrier, comprising: a base (20), the base (20) defining a transport track; A carrier (10), wherein the carrier (10) is movable along the transport track; and A plurality of active magnetic bearings (30), the plurality of active magnetic bearings (30) being arranged at the base (20) and being configured to face a guide structure (12) of the carrier, the guide structure (12) comprising: a first guide region (13) and a second guide region (14), wherein the first guide region (13) and the second guide region (14) are configured to interact with the plurality of active magnetic bearings (30); and A recessed area (15), wherein the recessed area (15) is arranged between the first guide area (13) and the second guide area (14) in the transport direction (T) of the carrier, the recessed area is recessed relative to the first guide area (13) and the second guide area (14), and the recessed area (15) has a size of 1 m or more in the transport direction.

2. The magnetic suspension system according to claim 1, wherein the first guide area (13) and the second guide area (14) define a first plane (P1), the first plane (P1) being at a first distance from the plurality of active magnetic bearings (30) during transport of the carrier, and The recessed area (15) defines a second plane (P2) which, during transport of the carrier, has a second distance from the plurality of magnetic bearings that is greater than the first distance. 3 . The magnetic levitation system of claim 2 , wherein the first distance is 2 mm or less, and wherein the second distance is 3 mm or more.

4. The magnetic levitation system of claim 2, wherein the first distance is 1.5 mm, and wherein the second distance is 5 mm.

5. A magnetic levitation system as described in any one of claims 1 to 4, wherein the carrier (10) has an upper carrier surface, a front part of the upper carrier surface in the transport direction (T) constituting the first guide area (13), and a rear part of the upper carrier surface in the transport direction (T) constituting the second guide area (14).

6. The magnetic levitation system according to any one of claims 1 to 4, wherein the first guide area (13) and the second guide area (14) have a size of 30 cm or more in the transport direction.

7. The magnetic levitation system according to any one of claims 1 to 4, wherein the recessed area (15) has a dimension of 2 m or more in the transport direction.

8. The magnetic levitation system according to any one of claims 1 to 4, further comprising one or more controllers (50), wherein the one or more controllers (50) are used to individually control the multiple active magnetic bearings (30) according to the position of the carrier along the transport track.

9. A magnetic levitation system as described in any one of claims 1 to 4, wherein one or more controllers (50) are constructed to actively control at least one magnetic bearing (31) when at least one magnetic bearing (31) of the multiple active magnetic bearings (30) faces one of the first guide area (13) and the second guide area (14), and / or wherein the one or more controllers (50) are constructed to turn off the active control of the at least one magnetic bearing (31) when the at least one magnetic bearing (31) faces the recessed area (15).

10. The magnetic levitation system of any one of claims 1 to 4, further comprising a linear motor (60) for moving the carrier (10) along the transport track, wherein the linear motor (60) is configured to determine a position of the carrier along the transport track and send the position of the carrier to one or more controllers (50) of the plurality of active magnetic bearings (30).

11. The magnetic levitation system according to any one of claims 1 to 4, wherein a plurality of permanent magnets (18) configured to contribute to the levitation force of the carrier are arranged at the recessed area (15).

12. The magnetic levitation system of claim 11, wherein the plurality of permanent magnets (18) are arranged in two parallel tracks at a distance corresponding to the distance between the magnetic material components (19) of the plurality of active magnetic bearings (30).

13. A carrier (10) of a magnetic levitation system, the carrier being movable along a transport track defined by a base (20), the carrier comprising: A guide structure (12), the guide structure (12) comprising a first guide area (13) and a second guide area (14), the first guide area (13) and the second guide area (14) being configured to interact magnetically with a plurality of active magnetic bearings (30); and A recessed area (15), which is arranged between the first guide area (13) and the second guide area (14) in the transport direction (T) of the carrier and is recessed relative to the first guide area (13) and the second guide area (14), wherein the recessed area (15) has a size of 1m or more in the transport direction.

14. A method for suspending a carrier (10), the carrier comprising a first guide area (13), a second guide area (14) and a recessed area (15) located between the first guide area (13) and the second guide area (14) in a transport direction (T) of the carrier, wherein the recessed area (15) has a size of 1 m or more in the transport direction, the method comprising: A plurality of active magnetic bearings (30) are controlled to suspend the carrier (10) relative to the base (20), and the first guide area (13) and the second guide area (14) magnetically interact with the plurality of active magnetic bearings.

15. A method as claimed in claim 14, wherein a first subset of the multiple active magnetic bearings facing one of the first guide area (13) and the second guide area (14) is actively controlled or opened, and a second subset of the multiple active magnetic bearings facing the recessed area (15) is not actively controlled or closed.

16. The method of claim 15, further comprising: transporting the carrier (10) along a transport track defined by the base (20); and The position of the carrier along the transport track is repeatedly determined and magnetic bearings of the plurality of active magnetic bearings (30) are assigned to the first subset or the second subset depending on the carrier position.

17. A method as claimed in claim 15 or 16, wherein a first part of the suspension force for suspending the carrier acts between the first subset of the multiple active magnetic bearings and the first guide area and the second guide area, and a second part of the suspension force acts between the second subset of the multiple active magnetic bearings and the multiple permanent magnets (18) arranged in the recessed area (15).

18. The method of claim 17, wherein the first portion of the levitation force is actively controlled to maintain a constant distance between the first subset and the first and second guide regions.

19. The method of claim 17, wherein the second portion of the levitation force is generated by a passive unit.

20. The method of claim 14 or 15, wherein the carrier has a substantially vertical orientation during transport.

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