METHOD OF OPERATING A CLOSING DEVICE

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to a closing device, particularly to a closing device for closing an opening between a first pressure region and a second pressure region in a vacuum-tight manner. More specifically, a closing device for closing an opening of a vacuum chamber is described. Embodiments further relate to a vacuum system comprising a vacuum chamber and a closing device for closing an opening of the vacuum chamber in a vacuum-tight manner. Embodiments further relate to a method of operating a closing device, particularly a method of closing an opening of a vacuum chamber.

BACKGROUND

[0002] Lock valves, gate valves, gates and other closing devices can be used to close a vacuum chamber with respect to an atmospheric environment in a vacuum-tight manner or to separate regions of a vacuum system having different pressures from each other. For example, a gate valve or another closing device can be used as a closable door of a vacuum chamber or as a closable passage between two vacuum regions, in order to transport substrates or other objects into a vacuum chamber, out of a vacuum chamber, or between two vacuum regions of a vacuum system, when the closing device is in an open position. In a closed position of the closing device, two regions having different pressures are separated from each other by a blocking device such as a lid, a paddle or a closing plate of the closing device.

[0003] A closing device may include a flange which is typically a stationary component connected to or integrally formed with a wall of a vacuum chamber, wherein the flange is provided with an opening that is surrounded by a flange wall. The closing device may further include a movable blocking device such as a lid configured to close the opening of the flange in a vacuum-tight manner. In a closed position of the lid, the lid may sit on a sealing surface of the flange which surrounds the opening such that the opening is sealed. In an open position of the lid, the opening may be used for transporting components such as substrates or masks therethrough. [0004] Substrate sizes, e.g. for optical, electronic, or opto -electronic applications such as displays and/or OLED devices, are continuously increasing. Accordingly, it would be beneficial to provide a closing device with a large opening configured to transport large- area substrates therethrough in an open position. For example, the opening of a closing device may have an area of 0.5 m ² or more. [0005] A relevant factor in closing devices is the deformation of the lid and of the flange, e.g. when the lid is pressed toward the sealing surface of the flange in the closed state of the closing device. The consequence of a deformation may be a non-uniform pressure between the lid and the flange, particularly a non-uniform pressure on a sealing element. Accordingly, a high closing force may be needed which may in turn lead to particle generation in the vacuum system, e.g. due to frictional forces between the flange and the lid. Particle generation may negatively affect the vacuum quality. Further, small particles in a vacuum deposition system may negatively affect the deposition result, because some of the particles may become attached to a substrate.

[0006] Similarly, relative movements between an elastic sealing element and the lid during a closing movement of the lid may lead to particle generation.

[0007] Accordingly, it would be beneficial to provide a closing device for a vacuum chamber that is configured to reliably close also large openings, while reducing particle generation due to frictional forces in the vacuum chamber.

SUMMARY [0008] In light of the above, a closing device, a vacuum system as well as a method of operating a closing device are provided.

[0009] According to an aspect of the present disclosure, a closing device is provided. The closing device includes a flange to be provided at a vacuum chamber and including an opening; a blocking device configured to close the opening; a first magnetic device configured to generate a magnetic closing force between the flange and the blocking device for transferring the blocking device or a part of the blocking device from an open position to a closed position; and a magnetic levitation system configured to contactlessly transport the blocking device along a guiding structure in a first direction parallel to the flange, wherein the magnetic levitation system includes a second magnetic device configured to stabilize the blocking device in a second direction transverse to the first direction.

[0010] In some embodiments, the flange with the opening may be integrally formed with or connected to a vacuum chamber. Accordingly, the flange opening may constitute an opening in an inner or an outer wall of a vacuum chamber.

[0011] According to a further aspect of the present disclosure, a vacuum system is provided. The vacuum system includes a vacuum chamber; a flange provided at an inner or an outer wall of the vacuum chamber and including an opening; a blocking device configured to close the opening; a first magnetic device configured to generate a magnetic closing force between the flange and the blocking device for transferring the blocking device or a part of the blocking device from an open position to a closed position; and a magnetic levitation system configured to contactlessly transport the blocking device in a first direction parallel to the flange, wherein the magnetic levitation system includes a second magnetic device configured to stabilize the blocking device in a second direction transverse to the first direction.

[0012] In some embodiments, the vacuum system may include at least one deposition source, such as a vapor source, configured to deposit one or more layers on a substrate under sub-atmospheric conditions in the vacuum system. [0013] According to a further aspect described herein, a method of operating a closing device is provided. The method includes contactlessly transporting a blocking device in a first direction parallel to a flange, wherein the flange is provided at a vacuum chamber and includes an opening; magnetically stabilizing the blocking device in a second direction transverse to the first direction with a second magnetic device; and generating a magnetic closing force between the flange and the blocking device with a first magnetic device for transferring the blocking device or a part of the blocking device from an open position to a closed position in which the blocking device seals the opening.

[0014] Further aspects, advantages and features of the present disclosure are apparent from the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the present disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following. Typical embodiments are depicted in the drawings and are detailed in the description which follows.

[0016] FIG. 1A is a schematic sectional view of a closing device according to some embodiments described herein in an open position (I);

[0017] FIG. IB is a schematic sectional view of the closing device of FIG. 1A in a closed position (II) in which a blocking device seals an opening of a flange;

[0018] FIG. 2A is a schematic front view of the closing device of FIG. 1A, wherein the blocking device has been transported to a position distant from the opening;

[0019] FIG. 2B is a schematic front view of the closing device of FIG. 1A, wherein the blocking device is arranged in front of the opening; [0020] FIG. 3A is a schematic front view of a closing device according to some embodiments described herein in a closed position (II);

[0021] FIG. 3B is a schematic front view of the closing device of FIG. 3 A, wherein the blocking device has been transported away from the opening;

[0022] FIG. 4 is a schematic sectional view of the closing device of FIG. 3A, wherein a head part and a bottom part are additionally depicted in an enlarged view; [0023] FIG. 5 is a schematic sectional view of a closing device according to some embodiments described herein; and

[0024] FIG. 6 is a flow diagram illustrating a method of operating a closing device according to embodiments described herein. DETAILED DESCRIPTION OF EMBODIMENTS

[0025] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in the figures. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations.

[0026] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0027] FIG. 1A is a schematic sectional view of a closing device 100 according to embodiments described herein in an open position (I) in which a blocking device 120 is arranged in front of an opening 112 of a flange 110, but does not close the opening 112 in a vacuum-tight manner. FIG. IB is a schematic sectional view of the closing device 100 of FIG. 1A in a closed position (II) in which the blocking device 120 closes the opening 112 in a vacuum-tight manner.

[0028] A "closing device" as used herein may be understood as an arrangement configured for opening and closing an opening between two regions which are to be maintained at different pressures, e.g. an inner space and an environment of a vacuum chamber, such as, but not limited to, a gate valve, a lock valve, a gate lock or a door such as a sliding door of a vacuum system. [0029] A "blocking device" as used herein may be understood as a movable component that is utilized for closing the opening in a vacuum-tight manner. For example, the blocking device may be configured as or may include a movable plate, a lid, or a paddle.

[0030] The flange 110 may include a counterplate for the blocking device 120. In particular, the flange 110 may have a sealing surface which surrounds the opening 112, wherein the blocking device 120 can be pulled toward the sealing surface of the flange 110 in the closed position (II) of the closing device. A sealing element such as an elastic sealing may act between the blocking device 120 and the flange 110 in the closed position (II). [0031] For example, at least one sealing element may be provided in the sealing surface of the flange 110, wherein the at least one sealing element may include a sealing ring which surrounds the opening 112. When the blocking device 120 is moved toward the sealing surface of the flange, the at least one sealing element may be pressed onto a surface of the blocking device 120 such that the opening 112 is sealed (see FIG. IB). In some embodiments, at least one sealing element may be provided in a sealing surface of the blocking device which is directed toward the sealing surface of the flange.

[0032] The flange 110 may be attached to a vacuum chamber (not shown in FIG. 1A) such that the opening of the flange 110 provides an opening in an outer wall or in an inner wall of the vacuum chamber. In some embodiments, the flange 110 may be integrally formed with a vacuum chamber. For example, the flange may be a wall section of the vacuum chamber which surrounds an opening in the chamber.

[0033] The closing device 100 includes the blocking device 120 which is movable with respect to the flange 110. In particular, the blocking device 120 can be transferred between the open position (I) depicted in FIG. 1A and the closed position (II) depicted in FIG. IB in which the blocking device seals the opening in a vacuum-tight manner. The movement of the blocking device from the open position to the closed position may be in a direction perpendicular to the flange, e.g. perpendicular to the sealing surface of the flange. More particularly, the blocking device may be moved toward the sealing surface to the closed position, while the blocking device and the flange are oriented parallel to each other. Accordingly, the sealing element can be uniformly compressed in a direction perpendicular to the flange such that particle generation due to a relative movement under frictional contact between the flange and the blocking device can be reduced or avoided.

[0034] The blocking device 120 may be oriented essentially vertically. In other words, the main orientation of the blocking device 120 may be an essentially vertical orientation, wherein "essentially vertical" may encompass a deviation of +/-20 ⁰ from the gravity axis. Accordingly, also the flange 110 may be essentially vertically oriented. For example, the opening 112 may be an opening in a side wall of the vacuum chamber. In other embodiments, the blocking device 120 and the flange 110 may be oriented essentially horizontally. For example, the opening 112 may be an opening in a top wall of a vacuum chamber.

[0035] The closing device 100 further includes a first magnetic device 130 configured to generate a magnetic force between the flange 110 and the blocking device 120 for transferring the blocking device 120 (or at least a part of the blocking device) from the open position of FIG. 1A to the closed position of FIG. IB. The magnetic force between the flange 110 and the blocking device 120 may be an attractive magnetic force which pulls the blocking device toward the sealing surface of the flange.

[0036] In some embodiments, the first magnetic device 130 includes one or more magnets, particularly electromagnets, which may be provided at the flange 110 such that the blocking device 120 can be pulled toward the sealing surface of the flange by a magnetic closing force that can be generated by the one or more magnets. The direction of the magnetic closing force is indicated by two leftward directed arrows in FIG. IB. In particular, the first magnetic device 130 may include a plurality of magnets which are arranged at the flange 110 and which are provided at positions distributed around the opening. For example four or more magnets may be arranged at the flange adjacent to the opening, respectively.

[0037] The first magnetic device 130 may be a controllable magnet device configured to generate a controllable magnetic closing force. For example, an actively controlled magnet device may be provided. In particular, the magnetic field strength generated by the first magnet device may be variable, e.g. depending on a distance between the blocking device and the flange and/or depending on a pressure difference on both sides of the blocking device. In some embodiments, the first magnetic device 130 may be configured to generate selectively an attractive or a repulsive force between the blocking device and the flange, such that the blocking device may be selectively opened and closed by the first magnetic device 130. In other embodiments, the first magnetic device 130 may be configured to only provide an attractive force between the blocking device and the flange for closing the blocking device.

[0038] The magnetic closing force may act in a direction essentially perpendicular to the flange, i.e. perpendicular to the sealing surface of the flange. This direction is also referred to as a second direction (X) in the following. In the open position (I) depicted in FIG. 1A, a distance between the blocking device and the flange may be a small distance, e.g. 1 cm or less, particularly 5 mm or less. The first magnetic device 130 may be configured for transferring the blocking device or a part of the blocking device by said distance of 1 cm or less, particularly 5 mm or less, from the open position to the closed position. A uniform deformation of the sealing element which may act between the blocking device and the flange can be achieved, and particle generation due to frictional forces can be reduced.

[0039] The second direction (X) is typically a horizontal direction, and the flange is typically essentially vertically oriented. However, it is also possible to close a horizontally oriented flange with a blocking device which moves in an essentially vertical direction between an open position and a closed position. [0040] The blocking device 120 may include a closing plate configured to be pressed toward the sealing surface of the flange. The closing plate may be at least partially made of a magnetic material, e.g. a metal containing iron, particularly steel. Further, the closing plate may be a rigid and stiff component, in order to reduce deformations of the blocking device in the closed position (II). [0041] The closing device 100 further includes a magnetic levitation system 150 configured to contactlessly transport the blocking device 120 along a guiding structure in a first direction (T) parallel to the flange 110. The magnetic levitation system includes a second magnetic device 160 configured to stabilize the blocking device 120 in a second direction (X) transverse to the first direction (T), particularly perpendicular to the first direction (T). Both the first direction (X) and the second direction (T) are typically essentially horizontal directions. However, other embodiments are possible.

[0042] Accordingly, the blocking device 120 is movable in at least two directions: the blocking device can be transferred between the closed position (II) and the open position (I) in a direction away from the flange, i.e. perpendicular thereto, and the blocking device can be transported in a second direction essentially parallel to the flange by the magnetic levitation system in a contactless manner. The transport of the blocking device in the second direction (T) may be performed in a sliding door-like manner.

[0043] FIG. 2A and FIG. 2B show schematic front views of the closing device 100 of FIG. 1A and FIG. IB viewed from the right side. In FIG. 2A, the blocking device 120 has been transported with respect to the flange 110 via the magnetic levitation system 150 toward the side in the first direction (T). Accordingly, the opening 112 of the flange 110 is no longer covered by the blocking device 120 such that objects can be moved through the opening 112 in an unhindered way. For example, objects such as substrates or masks can be loaded through the opening 112 into or out of a vacuum chamber. The position depicted in FIG. 2A may therefore also be referred to as a "loading position".

[0044] In FIG. 2B, the blocking device 120 is arranged in front of the opening 112 and blocks the opening. The position depicted in FIG. 2B may therefore be referred to as a "blocking position". The sectional views of FIG. 1A and IB show the closing device 100 in the blocking position.

[0045] The guiding structure may include several tracks or rails for contactlessly guiding the blocking device 120 in the first direction (T) which is a direction perpendicular to the paper plane of FIG. 1A and parallel to the paper plane of FIG. 2A. For example, a top rail 182 may be provided at least partially above the blocking device 120, and at least one side guiding rail, e.g. an upper side guiding rail and a lower side guiding rail, may be provided on the sides of the blocking device. The second magnetic device 160 may be provided along the at least one side guiding rail, and a third magnetic device may be provided at the top rail for holding the blocking device. The top rail 182 and/or the at least one side guiding rail may have a length in the first direction (T) that is longer than a width of the opening 112 in the first direction (T), particularly longer than 50 cm, more particularly longer than 75 cm. For example, the blocking device 120 can be transported in the first direction (T) along the guiding structure by a distance of 20 cm or more, particularly 30 cm or more. In the position depicted in FIG. 2B the opening 112 may be completely unblocked. [0046] The magnetic levitation system 150 is configured to contactlessly hold the blocking device at the guiding structure and to contactlessly transport the blocking device along the guiding structure in the second direction (T), i.e. parallel to the flange 110. For example, in FIG. 1A, the blocking device 120 is contactlessly held at the guiding structure, e.g. below the top rail 182 and between the side guiding rails. Accordingly, when the blocking device 120 is transported in the second direction (T), the blocking device has no mechanical contact with the guiding structure and/or with another stationary component of the vacuum chamber such that particle generation due to a frictional contact of the blocking device can be further reduced. A contactless transport of the blocking device is particularly beneficial in cases where the blocking device is configured to close a passage inside a vacuum system, e.g. a passage between two vacuum chambers.

[0047] The second magnetic device 160 may be configured to stabilize the blocking device 120 in the second direction (X) which may extend perpendicular to the first direction (T). In other words, the second magnetic device 160 may be configured to stabilize the blocking device 120 in a direction perpendicular to the transport direction of the blocking device 120.

[0048] Stabilizing the blocking device in the second direction (X) perpendicular to the transport direction with the second magnetic device 160 may provide several advantages. For example, a distance between the blocking device and the flange may be maintained as appropriate during the transport of the blocking device, while allowing for a contactless transport. Further, a parallel orientation of the blocking device with respect to the sealing surface of the flange may be obtained and maintained by a side stabilization of the blocking device. A contactless magnetic side stabilization of the blocking device is further beneficial, because particle generation can be reduced and a high positioning accuracy can be achieved. [0049] In some embodiments, the second magnetic device 160 may be configured to hold the blocking device at a predetermined distance from the flange during the transport in the first direction (T). For example, the second magnetic device 160 may provide a two- side stabilization. In other words, if the blocking device tends to move away from the flange during the transport, the second magnetic device may urge the blocking device back toward the flange, and if the blocking device tends to move too close to the flange during the transport, the second magnetic device may urge the blocking device away from the flange toward an equilibrium position that is depicted in FIG. 1A. The second magnetic device 160 may be configured to act on the blocking device via magnetic forces. [0050] In some embodiments, the second magnetic device 160 includes a plurality of magnets, e.g. electromagnets and/or permanent magnets. Permanent magnets may be beneficial because no electrical power is needed. For example, permanent magnets may act from two opposite sides on the blocking device in order to stabilize the blocking device at the equilibrium position that is depicted in FIG. 1A during the transport along the guiding structure.

[0051] In some embodiments, which may be combined with other embodiments described herein, the second magnetic device 160 includes a passive magnetic stabilizing device. A passive magnetic stabilizing device may be understood as a magnetic device which is not actively controlled. For example, no output parameter such as an electric current is controlled depending on an input parameter such as a distance. Rather, the passive magnetic stabilizing device may stabilize the blocking device at a predetermined position without any feedback control.

[0052] In some embodiments, the second magnetic device 160 may include a first plurality of permanent magnets 165 fixed to at least one side of the blocking device 120 and a second plurality of permanent magnets 166 fixed to the guiding structure, e.g. to a side guiding portion of the guiding structure. The first plurality of permanent magnets 165 on the blocking device may face toward the second plurality of permanent magnets 166 on the side guiding portion such as to generate repulsive forces between the first plurality of permanent magnets 165 and the second plurality of permanent magnets 166. In particular, poles of the same polarities (north poles or south poles) of the first and second pluralities of permanent magnets may be directed toward each other such as to generate repulsive forces.

[0053] In some embodiments, the guiding structure may include a first side guiding portion 168 arranged on a first side of the blocking device 120 and a second side guiding portion 169 arranged on a second side of the blocking device opposite the first side, wherein permanent magnets of the second plurality of permanent magnets 166 are attached to both the first side guiding portion 168 and the second side guiding portion 169. Further, permanent magnets of the first plurality of permanent magnets 165 may be attached to two opposite sides of the blocking device 120. Accordingly, the blocking device 120 may be urged into an equilibrium position between the first side guiding portion 168 and the second side guiding portion 169 by the oppositely directed magnetic forces acting on both sides of the blocking device.

[0054] In FIG. 1A, poles of one polarity (e.g. south poles) are depicted with horizontal shaded lines, and poles of the opposite polarity (e.g. north poles) are depicted with vertical shaded lines. As can be seen from FIG. 1A, poles of the same polarity face toward each other on a first side of the blocking device such that the blocking device is urged away from the first side guiding portion 168, and poles of the same polarity face toward each other on a second side of the blocking device such that the blocking device is urged away also from the second side guiding portion 169. Accordingly, the blocking portion may be stabilized at a center position between the first and second side guiding portions.

[0055] In some embodiments, which may be combined with other embodiments described herein, the second magnetic device 160 may include a lower magnetic stabilizing device 162 for stabilizing a lower portion of the blocking device 120. For example, a bottom edge of the blocking device 120 may protrude into a U-shaped guiding rail 167 of the guiding structure, as is schematically depicted in FIG. 1A. The U-shaped guiding rail may include a first side guiding portion 168 with permanent magnets on a first side of the blocking device and a second side guiding portion 169 with permanent magnets on a second side of the blocking device. The permanent magnets arranged on both sides of the blocking device urge the blocking device into the equilibrium position which may correspond to a center position of the U-shaped guiding rail 167 between the first side guiding portion 168 and the second side guiding portion 169. [0056] Alternatively or additionally, an upper magnetic stabilizing device 161 for stabilizing an upper portion of the blocking device 120 in the second direction (X) may be provided. Similar to the lower magnetic stabilizing device 162, the upper magnetic stabilizing device 161 may include a first side guiding portion 168 and a second side guiding portion 169, wherein the blocking device 120 may be arranged between the first side guiding portion 168 and the second side guiding portion 169 and may be urged to an equilibrium position by magnetic forces acting from both sides onto the blocking device 120.

[0057] By providing an upper and a lower magnetic stabilizing device, an orientation of the blocking device 120 can be accurately set as appropriate. For example, a vertical orientation of the blocking device can be ensured.

[0058] In some embodiments, which may be combined with other embodiments described herein, a first plurality of permanent magnets 165 and a second plurality of permanent magnets 166 may be arranged on both sides of the blocking device 120 such as to generate a magnetic force effect acting in a vertically upward direction. Said magnetic force effect may urge the blocking device 120 upward, such that a portion of the weight of the blocking device 120 can be carried by the second magnetic device 160. Simply put, the blocking device 120 which is urged from both sides into the equilibrium position between the first side guiding portion 168 and the second side guiding portion 169 tries to escape from said oppositely acting magnetic forces by being lifted upward in a vertical direction.

[0059] The vertically acting force effect of the second magnetic device 160 may be increased by providing first permanent magnets fixed to the blocking device 120 at a first height which is different from a second height of second permanent magnets fixed to the guiding structure. For example, as is schematically depicted in FIG. 1A, first permanent magnets fixed to the blocking device 120 are arranged slightly higher than second permanent magnets fixed to the guiding structure in order to obtain a magnetic force acting vertically upward.

[0060] In some embodiments, both a lower magnetic stabilizing device 162 and an upper magnetic stabilizing device 161 may provide a vertical force effect, as is schematically depicted in FIG. 1A. [0061] In some embodiments, the second magnetic device 160 may be configured to generate a vertical magnetic force acting on the blocking device 120 which may carry 10% or more, particularly 20% or more, more particularly 50% or more of the weight of the blocking device 120. For example, the permanent magnets of the second magnetic device 160 may be configured to carry a weight of 20 kg or more, particularly 50 kg or more of the blocking device 120. Providing permanent magnets which carry at least a part of the weight of the blocking device may be beneficial, because no power supply for the permanent magnets is needed.

[0062] The magnetic closing force of the first magnetic device 130 may pull the blocking device 120 out of the equilibrium position depicted in FIG. 1A toward the flange 110 into the closed position (II) depicted in FIG. IB.

[0063] In some embodiments, which may be combined with other embodiments described herein, the second magnetic device 160 may be configured to transfer the blocking device from the closed position (II) to the open position (I). In particular, the first magnetic device 130 may be configured to generate the magnetic closing force for closing the blocking device, and the second magnetic device 160 may be configured to generate a magnetic force for opening the blocking device. For transferring the blocking device 120 from the closed position (II) to the open position (I), the magnetic closing force of the first magnet device 130 may be reduced or switched off, such that the magnetic stabilizing force of the second magnetic device 160 may move the blocking device away from the flange 110 into the equilibrium position that is depicted in FIG. 1A, which corresponds to the open position (I).

[0064] Since the second magnetic device 160 may be a passive magnetic device including permanent magnets, no additional power may be needed for opening the blocking device. Rather, for opening the blocking device, it may be sufficient to reduce or switch off the magnetic closing device.

[0065] In some embodiments, which may be combined with other embodiments described herein, the magnetic levitation system 150 may include a third magnetic device 180 configured to contactlessly hold the blocking device at the guiding structure. The third magnetic device 180 may be arranged at least partially above the blocking device 120 and may generate a vertical magnetic force which may pull the blocking device 120 upward. In particular, the blocking device 120 may hang below a top rail 182 of the guiding structure via a magnetic pulling force generated by the third magnetic device 180.

[0066] The third magnetic device 180 may include a plurality of active magnetic bearings 184. For example, coils of the active magnetic bearings 184 may be integrated in the blocking device 120 and/or coils of the active magnetic bearings 184 may be integrated in the guiding structure, e.g. in the top rail 182 of the guiding structure.

[0067] In the embodiment of FIG. 1A and FIG. IB, the active magnetic bearings 184 are integrated in the guiding structure. A head portion of the blocking device 120 arranged below the active magnetic bearings 184 may be pulled toward the active magnetic bearings 184. The third magnetic device 180 may carry at least a part of the weight of the blocking device. As already indicated above, a further part of the weight of the blocking device may be carried by a vertical magnetic force effect generated by the second magnetic device 160. In other embodiments, the whole weight of the blocking device 120 may be carried by the third magnetic device 180.

[0068] An active magnetic bearing 184 may be understood as an actively controlled magnetic actuator. For example, an output parameter such as an electric current which is applied to the active magnetic bearing may be controlled depending on an input parameter such as a distance, e.g. a distance between the blocking device 120 and the guiding structure. In particular, a distance between the top rail 182 and the blocking device 120 may be measured by a distance sensor, and the magnetic field strength of the active magnetic bearing may be set depending on the measured distance. The magnetic field strength may be increased in the case of a distance above a predetermined threshold value, and the magnetic field strength may be decreased in the case of a distance below the threshold value. The active magnetic bearings 184 may be controlled in a closed loop or feedback control. Magnetic counterparts may be attached to an upper part of the blocking device 120 which are attracted by the active magnetic bearings 184 in the top rail 182.

[0069] Thus, the blocking device 120 can be held and transported in a contactless floating state at the guiding structure which is beneficial, because contamination such as particle generation in the vacuum system can be reduced or avoided. [0070] In some embodiments, each active magnetic bearing 184 may include a magnetic actuator and a distance sensor for measuring a distance between the blocking device and the guiding structure, wherein the magnetic actuator may be controlled depending on the measured distance, particularly in a control loop or feedback loop. [0071] Oscillations of the blocking device 120 which may be stimulated by an active control can be reduced, when the active magnetic bearings 184 act in a direction in which the blocking device 120 is extremely stiff, particularly in an essentially vertical direction. On the other hand, the blocking device may be more flexible in the second direction (X), i.e. in a side direction. However, stimulated oscillations in the side direction can be reduced or avoided, when the second magnetic device 160 which provides the side stabilization of the blocking device is configured as a passive magnetic stabilization device. Accordingly, an accurate contactless transport of the blocking device without the risk of stimulated oscillations becomes possible.

[0072] A plurality of active magnetic bearings 184 may be provided along the guiding structure in the first direction (T), as is schematically indicated in FIG. 2A and FIG. 2B. For example, three, five, ten or more active magnetic bearings may be provided. In some embodiments, a distance between two adjacent active magnetic bearings may be smaller than a width dimension of the blocking device 120 in the first direction (T), such that at least two active magnetic bearings may be engaged with the blocking device at any time during the transport.

[0073] In some embodiments, the blocking device 120 is configured as a closing plate which hangs contactlessly below the top rail 182 of the guiding structure, wherein the plurality of active magnetic bearings 184 are attached to the top rail 182. In particular, the blocking device 120 itself may be a purely passive component, i.e. may be transportable without a supply of media such as electricity to the blocking device 120. For example, as is shown in FIG. 1A, the active components of the first magnetic device 130 and the third magnetic device 180 may be integrated in the flange 110 and in the guiding structure, respectively, and the blocking device 120 may include purely passive components such as the first plurality of permanent magnets 165. Providing the movable blocking device as a passive component is beneficial, because no movable media supply device for the blocking device such as a drag chain may be needed. [0074] The magnetic levitation system 150 may be configured to transfer the entire blocking device from the open position (I) to the closed position (II). In particular, the blocking device 120 may be formed as one monolithic or rigid part such as a metal plate or a metal paddle which can be transferred as a whole between the open position (I) and the closed position (II) and which can be transported as a whole in the first direction (T) by the magnetic levitation system 150.

[0075] In other embodiments, the blocking device 120 may include several parts which may be movable with respect to each other, wherein a subset of said parts may remain stationary during the movement of a part of the blocking device 120 between the open position and the closed position. For example, the blocking device may include a closing plate which is movably held with respect to a carrier such as a frame or a cart. The carrier and the closing plate may be transported in combination by the magnetic levitation system 150 in the first direction (T), but the closing plate may be transferred without the carrier in the second direction (X) by the first magnetic device 130. [0076] In some embodiments, which may be combined with other embodiments described herein, the magnetic levitation system 150 may further include a drive 170 for moving the blocking device 120 along the guiding structure in the first direction (T). The drive may be a linear motor which can drive the blocking device 120 contactlessly along a drive structure. Other contactless drives can be provided additionally or alternatively. [0077] FIG. 2A shows the closing device 100 of FIG. 1A in a schematic front view. The blocking device 120 has been transported to the left side with respect to the opening 112 of the flange 110 in a sliding door-like manner such that the opening 112 is in a loading position in which objects can be loaded through the opening 112. FIG. 2B shows the closing device 100 of FIG. 1A, wherein the closing device 100 is arranged in front of the opening 112 and covers the opening.

[0078] The magnetic levitation system is provided for the contactless transport of the blocking device 120 in the first direction (T), wherein the magnetic levitation system includes the third magnetic device 180 and the second magnetic device 160. The second magnetic device 160 may include a passive magnetic stabilization device for providing a stabilization of the blocking device 120 in the second direction (X). The second magnetic device 160 may optionally include an upper magnetic stabilizing device 161 and a lower magnetic stabilizing device 162. The third magnetic device 180 may be configured for actively stabilizing a vertical position of the blocking device 120. The third magnetic device may be arranged at least partially above the blocking device. The third magnetic device 180 may be configured to carry at least a part of the weight of the blocking device 120 and to maintain a predetermined vertical position of the blocking device 120.

[0079] Further, the drive 170 for driving the blocking device 120 in the transport direction (T) is shown in FIG. 2A and FIG. 2B. The drive 170 may be arranged at a side of the blocking device 120. Alternatively, the drive 170 may be arranged above or below the blocking device 120, e.g. integrated in the top rail 182 or in a bottom rail of the guiding structure.

[0080] FIG. 3A is a schematic front view of a closing device 200 according to embodiments described herein in a closed position in which a blocking device 220 closes and seals an opening 112 (shown in a dashed line in FIG. 3A) of a flange 110. FIG. 3B is a schematic front view of the closing device 200 of FIG. 3A in which the blocking device 220 has been transported into a loading position in which objects can be loaded through the opening 112.

[0081] FIG. 4 is a sectional view of the closing device 200 of FIG. 3A. An upper portion of the closing device 200 and a lower portion of the closing device 200 are depicted in respective enlarged views.

[0082] The closing device 200 is similar to the closing device 100 depicted in FIG. 1A and IB, such that reference can be made to the above explanations, which are not repeated here.

[0083] In particular, the blocking device 220 is configured to be transported in a first direction (T) via a magnetic levitation system between the positions depicted in FIG. 3A and 3B. The magnetic levitation system includes a second magnetic device 160 configured to stabilize the blocking device 220 in a second direction (X) transverse to the first direction (T), and a third magnetic device 180 configured to hold the blocking device. In some embodiments, the third magnetic device 180 is arranged at least partially above the blocking device 220, such that the blocking device can be contactlessly held below the third magnetic device 180 by a magnetic holding force. In some embodiments, the second magnetic device 160 is arranged on two opposite sides of the blocking device 220 such as to provide a magnetic side stabilization of the blocking device in the second direction (X). The second direction (X) may be a horizontal direction perpendicular to the first direction (T).

[0084] The third magnetic device 180 may be configured as an actively controlled device, particularly including active magnetic bearings 184 which are controlled in feedback loops such that a predetermined vertical position of the blocking device 220 can be maintained.

[0085] The second magnetic device 160 may be configured as a passive magnetic stabilizing device, as an active magnetic stabilizing device, or as a mixed active and passive magnetic stabilizing device. For example, a passive magnetic stabilizing device may be provided to stabilize a lower part of the blocking device 120, and an active magnetic stabilizing device may be provided to stabilize a head part of the blocking device 120 in the second direction (X), or vice versa. In other embodiments, a passive magnetic stabilizing device may be provided to stabilize a lower part of the blocking device 120, and a further passive magnetic stabilizing device may be provided to stabilize a head part of the blocking device 120 in the second direction (X), similar to the embodiment depicted in FIG. 1A.

[0086] In some embodiments, the active magnetic bearings 184 of the third magnetic device 180 may be integrated in the blocking device, particularly in a head part 222 of the blocking device 220. The top rail 182 may be configured as a purely passive track such as a simple metal track without actively controlled magnetic actuators. In particular, the active components of the third magnetic device 180 may be integrated in the blocking device 220, particularly in the head part 222 of the blocking device.

[0087] A media supply device may be provided for supplying the head part 222 of the blocking device with supply media, e.g. with electricity, control signals and/or cooling fluid. The media supply device may be configured as a drag chain. [0088] In some embodiments, the blocking device can be transported in the first direction (T) by a distance of 20 cm or more and 1 m or less. Providing a media supply device such as a drag chain for supplying the blocking device with supply media during the transport may be possible with an acceptable complexity due to the limited length of the transport path.

[0089] In some embodiments, active magnetic bearings 228 of an active magnetic side stabilizing device may be integrated in the blocking device, particularly in the head part 222 of the blocking device 220. For example, as is schematically depicted in FIG. 4, the head part 222 of the blocking device may include active magnetic bearings 184 of the third magnetic device providing a holding force in a vertical direction and active magnetic bearings 228 of the second magnetic device 160 providing an active side stabilization in a horizontal direction.

[0090] In some embodiments, the head part 222 of the blocking device 220 may be shaped such that the susceptibility of the head part 222 to stimulated oscillations is reduced in more than one direction. For example, the head part may be a massive metal component having a thickness of 5 cm or more, particularly 10 cm or more in at least two directions, e.g. in a vertical direction and in at least one side direction. For example, a cross- sectional shape of the head part 222 may be rectangular or essentially square-shaped with a minimum thickness of 5 cm. [0091] In particular, the position of the head part 222 may be actively stabilized in the vertical direction by the active magnetic bearings 184 and in the second direction (X) by the active magnetic bearings 228, wherein the thickness of the head part 222 both in the vertical and the second direction may be 5 cm or more. The stimulation of oscillations by said active stabilizations can be reduced. [0092] In some embodiments, the drive electronics, such as the drive electronics of the active magnetic bearings 184 and/or the drive electronics of a drive 170 for driving the blocking device in the first direction (T), may be integrated in the blocking device, particularly in the head part 222 of the blocking device. The top rail 182 may be a passive component, e.g. a simple metal rail. [0093] In particular, as is depicted in FIG. 4, a linear drive 170 may be provided for driving the blocking device 220 along the guiding structure in the first direction (T). A coil unit of the drive 170 may be integrated in the head part 222, wherein the coil unit of the drive 170 may be guided in magnet rail of the top rail 182, particularly wherein the magnet rail includes permanent magnets arranged along the first direction (T).

[0094] In some embodiments, which may be combined with other embodiments described herein, the blocking device 220 may include a lower part 221 and a head part 222 which may be movable with respect to each other. The lower part 221 may be arranged below the head part 222 and hang from the head part 222 via a mechanical connection. For example, the head part 222 and the lower part 221 may be connected via a flexible connection 225 such as a hinge connection. Accordingly, the head part 222 may be vibrationally decoupled from the lower part 221 so that potential oscillations of the head part due to the active stabilization of the head part may have a reduced effect on the lower part. [0095] The magnetic levitation system may be configured to transport both the head part 222 and the lower part 221 in unison in the first direction (T), as is depicted in figures 3 A and 3B. On the other hand, transferring the blocking device 220 from the open position (I) to the closed position (II) toward the flange 110 may include moving the lower part 221 of the blocking device without the head part 222 toward the flange 110. For example, the head part may remain in position, and only the lower part 221 may be attracted toward the flange 110 by the first magnetic device 130. The flexible connection 225 between the head part 222 and the lower part 221 may allow for a transferal of the lower part 221 toward the flange between the open position (I) and the closed position (II).

[0096] The second magnetic device 160 depicted in FIG. 4 may include a lower magnetic stabilizing device 162 which may be similar to the lower magnetic stabilizing device 162 of FIG. 1A, such that reference can be made to the embodiments described above, which are not repeated here.

[0097] According to a further embodiment described herein, a vacuum system 300 is provided. A vacuum system 300 according to embodiments described herein is schematically depicted in FIG. 5. The vacuum system 300 includes a vacuum chamber 101 (partially illustrated), particularly a plurality of vacuum chambers or vacuum modules which may be connected to each other. Closable passages or gate lock passages may be provided between some of the vacuum chambers or between a vacuum chamber and the atmospheric environment. A closing device according to any of the embodiments described herein may be provided for closing one or more of said passages, transits, gate locks or other openings of the vacuum system. FIG. 5 schematically depicts a part of a wall of a vacuum chamber 101 of an exemplary vacuum system.

[0098] A deposition source, particularly one or more of a vapor source, a sputter source and a CVD source may be arranged in at least one of the vacuum chambers of the vacuum system 300. Substrates to be coated may be transported through the vacuum system, e.g. between a vacuum chamber which houses the deposition source and an adjacent vacuum chamber. Particle generation in the vacuum system can be reduced and the deposition result can be improved by providing the vacuum system with one or more closing devices according to embodiments described herein. [0099] A flange 110 with an opening 112 is provided at an inner wall or at an outer wall of the vacuum chamber 101. The flange 110 may be fixed to the vacuum chamber. Further, a blocking device 120 such as a lid or a paddle configured to close the opening 112 is provided. The blocking device 120 can be transferred by a first magnetic device 130 between an open position that is shown in FIG. 5 and a closed position in which the blocking device seals the opening. The first magnetic device 130 is configured to generate a magnetic closing force between the flange 110 and the blocking device 120 for transferring the blocking device or a part of the blocking device from the open position to the closed position. Further, a magnetic levitation system 150 configured to contactlessly transport the blocking device 120 in a first direction (T) parallel to the flange 110 is provided, wherein the first direction (T) may be a direction perpendicular to the paper plane of FIG. 5. The magnetic levitation system includes a second magnetic device 160 configured to stabilize the blocking device in a second direction (X) transverse to the first direction (T) during the transport by the magnetic levitation system.

[00100] The closing device of the embodiment depicted in FIG. 5 may include some features or all the features of the closing device 100 of FIG. 1A and/or of the closing device 200 of FIG. 3A, such that reference can be made to the above explanations, which are not repeated here.

[00101] FIG. 5 shows the first magnetic device 130 and the flange 110 in more detail. The flange 110 may include a sealing surface 114, wherein an elastic sealing element 115 may be provided in the sealing surface 114. For example, the elastic sealing element 115 may be a sealing ring provided in a groove that is formed in the sealing surface 114. In the closed position, the blocking device 120 is pressed against the elastic sealing element 115 which may surround the opening 112.

[00102] The sealing surface 114 may be an essentially flat surface. In the open position, an essentially flat countersurface of the blocking device 120 may be arranged at a close distance from the sealing surface 114. The second direction (X) may be essentially perpendicular to the sealing surface 114. It is also possible to provide an elastic sealing element in the countersurface of the blocking device 120.

[00103] The magnetic closing force that is generated by a plurality of magnets 131 of the first magnetic device 130 may act in the second direction (X), i.e. perpendicular to the sealing surface 114. The blocking device 120 may include magnetic counterparts 132, e.g. iron or steel portions or permanent magnetic portions, which may be pulled toward the flange 110 by the magnetic closing force. Alternatively, the whole closing plate of the blocking device 120 may be made of a magnetic material such as steel. The plurality of magnets 131 may include electromagnets, particularly coils. By adjusting the electric current flowing through the coils, the magnetic closing force can be adapted as appropriate, i.e. depending on a measured pressure difference or depending on a measured distance.

[00104] In some embodiments, the first magnetic device 130 includes a distance sensor 135 for measuring a distance between the flange 110 and the blocking device 120. Accordingly, the magnetic closing force may be controlled depending on a distance measured by the distance sensor 135. The distance between the sealing surface 114 of the flange 110 and the blocking device 120 in the closed position can be accurately controlled, e.g. to avoid a direct metal contact between the flange and the blocking device in the closed position, e.g. during the evacuation of the vacuum chamber. [00105] One or more control loops 136 may be provided which couple the plurality of magnets 131 and one or more distance sensors. The control loop 136 may include a setpoint generator 137 which is connected to the distance sensor 135. The setpoint generator 137 compares the measured distance value with a preset distance setpoint which may be set by a central controller. A controller 139 may be supplied with a respective comparison signal which generates a control signal to be supplied to the plurality of magnets 131 via an amplifier 138. The amplified control signal is configured such that a predetermined distance between the blocking device 120 and the flange 110 can be maintained by the magnetic closing force generated by the plurality of magnets 131. The electronic elements of the control loop 136 may be configured as an integrated circuit, e.g. provided on a single board. Space requirements of the first magnetic device 130 can be reduced.

[00106] A plurality of control loops 136 may be provided such that a distance between the blocking device 120 and the flange 110 can be accurately set at a plurality of positions around the opening 112. Particle generation can be reduced and a uniform compression of the elastic sealing element 115 can be achieved.

[00107] In some embodiments, the plurality of magnets 131 which are provided as electromagnets at the flange may be configured to generate a variable attractive force between the blocking device 120 and the flange 110. The repulsive force between the blocking device 120 and the flange 110 may be the magnetic stabilizing force generated by the second magnetic device 160. The second magnetic device 160 may be a passive magnetic stabilizing device comprising permanent magnets which are arranged along the first transport direction (T) along respective side guiding rails. The permanent magnets of the second magnetic device 160 may urge the blocking device from two opposite sides into an equilibrium position that is depicted in FIG. 5. The second magnetic device 160 may include an upper magnetic stabilizing device 161 and a lower magnetic stabilizing device 162 configured to urge the blocking device into the equilibrium position.

[00108] FIG. 6 is a flow diagram for illustrating a method of operating a closing device in accordance with embodiments described herein. [00109] In box 610, a blocking device 120 is contactlessly transported in a first direction (T) parallel to a flange 110, wherein the flange is provided at a vacuum chamber and includes an opening. During the transport, the blocking device 120 is magnetically stabilized in a second direction (X) transverse, particularly perpendicular to the first direction (T) by a second magnetic device 160. During transport, the blocking device may have an essentially vertical orientation.

[00110] The blocking device 120 may be transported in a sliding door-like manner from a loading position in which the blocking device 120 does not block the opening to a blocking position in which the blocking device is arranged in front of the opening at a close distance from a sealing surface of the flange. In the loading position, objects such as substrates may be loaded through the opening. In the blocking position, the blocking device may be arranged in an orientation parallel to the orientation of the flange, particularly in a vertical orientation, at a close distance of, e.g., 1 cm or less in front of the opening. [00111] In box 620, a magnetic closing force is generated between the flange 110 and the blocking device 120 with a first magnetic device 130 for transferring the blocking device or a part of the blocking device from an open position (I) to a closed position (II) in which the blocking device seals the opening.

[00112] In particular, when the blocking device 120 has been transported to the blocking position in front of the opening, the first magnetic device 130 may be activated such that the blocking device is pulled toward a sealing surface of the flange in order to seal the opening in a vacuum-tight manner.

[00113] In optional box 630, the closing device is opened by transferring the blocking device from the closed position (II) back to the open position (I). The blocking device 120 may be transferred to the open position with a magnetic stabilizing force generated by the second magnetic device 160.

[00114] In particular, the blocking device 120 may be brought from the closed position to the open position by reducing or switching off the magnetic closing force of the first magnetic device 130 such that the magnetic stabilizing force of the second magnetic device 160 may shift the blocking device in a direction perpendicular to the flange to an equilibrium position in which the blocking device is held by the second magnetic device 160.

[00115] Then, the blocking device 120 may optionally be contactlessly transported by the magnetic levitation system in the first direction (T) parallel to the flange to the loading position in which objects can be fed through the opening.

[00116] The second magnetic device 160 may be or include a passive magnetic stabilizing device which may need no active control and/or no electric power.

[00117] Accordingly, a magnetic gate valve is provided according to embodiments described herein. The motion of the blocking device of the valve both in the first direction (T) and in the second direction (X) may be completely contactless and therefore frictionless. The only contact of the blocking device with a stationary structure may be in the closed position with the flange, particularly with an elastic sealing element of the flange. [00118] In some embodiments, the blocking device may have a height of 1 m or more, particularly 1.5 m or more in a vertical direction. In some embodiments, the blocking device may have a width in the first direction (T) of 30 cm or more, particularly 40 cm or more. The opening of the flange may have a cross sectional area of 0.5 m ² or more, particularly 1 m ² or more. [00119] The blocking device 120 may include a closing plate made at least partially of metal. The closing plate may be made at least partially of aluminum, in order to reduce the weight of the closing plate. The closing plate may include iron, particularly steel, as a magnetic material which interacts with one or more of the magnetic devices. For example, the blocking device may be an aluminum plate with steel parts for interacting with the first magnetic device 130, the second magnetic device 160, the third magnetic device 180 and/or the drive 170.

[00120] The second magnetic device 160 may be utilized for one or more of the following purposes, particularly when the second magnetic device 160 includes a passive magnetic guide based on permanent magnets: (i) side stabilization of the blocking device in the second direction perpendicular to the transport direction; (ii) reduce the stimulation of oscillations of the blocking device in a direction in which the blocking device has potentially many eigenfrequencies; (iii) partially compensate for the weight of the blocking device by generating a magnetic force effect in a vertical direction; (iv) use the magnetic stabilization force generated by the second magnetic device to open the blocking device.

[00121] A linear drive may be provided for driving the blocking device in a sliding motion in the first direction (T) along the guiding structure. The linear drive may include driving coils attached to the guiding structure and permanent magnets travelling with the blocking device.

[00122] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.