THEREOF

TECHNICAL FIELD OF THE INVENTION

[0001] Embodiments of the present invention relate to gas separation between different processing regions. Particularly, they relate to the separation of processing regions or vacuum chambers with different pressure regimes or different processing gases provided therein. Specifically, they relate to a gas separation device for separating processing regions being in fluid communication through an opening in a wall, a processing system for processing substrates therein, and a method of operating a gas separation device.

BACKGROUND OF THE INVENTION [0002] Substrate processing such as thin-film deposition, etching, patterning, or the like is conducted in a plurality of industrial applications. For example, displays with thin-film transistors (TFT) are widely used and can be generated by depositing thin layers on a substrate. Thereby, LEDs of semiconductor materials or organic light emitting diodes (OLED) can be used. As a further example, glasses can be coated for architectural purposes or other applications, such as electrochromic coated glass. According to yet further examples, thin-film solar cells can be manufactured by deposition of the layer stack of thin films for converting light energy into electrical energy.

[0003] These and other applications generally have different processing stations such as coating stations, which can, for example, be provided in an in-line processing system. In order to provide different processing steps or different deposited layers within a processing system in a cost-efficient manner, there is a desire to have different processing stations or coating stations adjacent to each other in the processing system. The increasing demand for new structures and for new applications can thereby result in increasing deviations of pressures within the vacuum chambers or of processing gases, such as reactive gases, in adjacent processing regions. In order to maintain the desired processing condition in each of the processing regions, a gas separation is typically provided such that the pressure and the mixture of the processing gas in the respective regions can be controlled independently. Thereby, tunnels or ducts can be used to provide low conductance for the processing gases between the processing regions. Further, if, for example, foils are processed in a roll-to-roll coating device, sweep gas or other measures can be used for avoiding cross-talk between the processing regions.

[0004] Particularly for large area substrates, the substrate-transfer-openings have to be increased in size which makes the use of tunnels or ducts more difficult. Yet, the use of isolating vacuum valves, which can seal the different processing regions with respect to each other, increases the costs of the processing system significantly. This increase of costs can be generated by at least one of the costs for the valve or additional vacuum chambers, which might be necessary in the system having a continuous substrate flow.

SUMMARY OF THE INVENTION

[0005] In light of the above, a gas separation device according to independent claim 1, a processing system for processing substrates therein according to claim 14, and a method of operating a gas separation device according to independent claim 15 are provided.

[0006] According to one embodiment, a gas separation device for separating evacuated processing regions, wherein the processing regions are in fluid communication with each other by an opening in a wall, are provided. The gas separation device includes at least one adjustable flow resistance control unit configured for adjusting the gas flow resistance between the evacuated processing regions, wherein the at least one adjustable flow resistance control unit includes at least one further opening. [0007] According to a further embodiment, a processing system for processing a substrate therein is provided. The processing system includes a first vacuum chamber providing a first processing region therein, a second vacuum chamber providing a second processing region therein, wherein at least one of the first vacuum chamber and the second vacuum chamber provides the wall having the opening therein, and at least one gas separation device, which is provided within the first vacuum chamber or the second vacuum chamber and which is provided adjacent to the opening in the wall. The gas separation device includes at least one adjustable flow resistance control unit configured for adjusting the gas flow resistance between the evacuated processing regions, wherein the at least one adjustable flow resistance control unit includes at least one further opening.

[0008] According to a yet further embodiment, a method of operating a gas separation device, particularly a gas separation device according to embodiments described herein is provided. The method includes switching the gas separation device to an open position, transferring one or more substrates or one or more carriers with substrates through the gas separation device and from a first evacuated processing region to a second evacuated processing region, wherein a first gap is provided when the one or more substrate or the one or more carriers are transferred through the gas separation device, and switching the gas separation device to a closed position after transfer of the one or more substrates or the one or more carriers such that a second gap is provided which has a flow resistance equal to or smaller than the first gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the invention and are described in the following:

Figure 1 is a schematic view of a processing system utilizing gas separation devices according to embodiments described herein;

Figure 2 is a schematic view of the gas separation device having a housing portion and a movable portion according to embodiments described herein;

Figure 3 is a schematic view illustrating the use of two gas separation devices as shown in Fig. 2;

Figures 4A and 4B are schematic views of a yet further gas separation device according to embodiments described herein and having a movable portion with an opening for trespassing of substrates therein;

Figure 5 is a schematic view of a yet further gas separation device having a movable portion for adjusting the flow resistance between two adjacent processing regions; Figure 6 is a schematic view of a yet further gas separation device having a housing portion and a movable portion according to embodiments described herein;

Figure 7 is a schematic view of yet a further gas separation device having a housing portion and a movable portion according to embodiments described herein; Figure 8 is a schematic view illustrating the use of two gas separation devices as shown in Fig. 7;

Figure 9 is schematic view illustrating switching of a gas separation device according to embodiments described herein; and Figure 10 is a flowchart illustrating a method of operating a gas separation device according to embodiments described herein.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0010] Reference will now be made in detail to the various embodiments of the invention, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to the same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the invention and is not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the present invention includes such modifications and variations.

[0011] Embodiments described herein relate to separation of processing regions such that gas transfer between the processing regions can be controlled. Thereby, different pressures, i.e., different levels of vacuum in different gas mixtures can be maintained in adjacent processing regions. Thereby, according to some embodiments, which can be combined with other embodiments described herein, it is referred to inline processing systems, such as inline coating systems, where one substrate after the other is moved through the processing system from one processing region to another processing region, i.e., one processing area to another processing area. Such an inline processing system may, in optimal conditions, transfer one substrate directly after the other substrate in order to maximize throughput. Thereby, the continuous flow of substrates, or a quasi-continuous flow of substrates, is provided. However, in some operation conditions, the continuous flow of substrates cannot be guaranteed. Thus, the opening or slit through which the substrates are transferred might not always have a substrate provided therein. In such a case, the gap between the first processing area and the second processing area is not filled or occupied with a substrate. Hence, a gas separation device having a switchable element should be provided when no substrate is provided in the opening.

[0012] As described herein, the element to be transferred through a processing system is sometimes referred to as a substrate and sometimes referred to a carrier. Typically, the substrates are to be processed in the processing system. For some embodiments, which can be combined with other embodiments described herein, the substrate can be provided in a carrier. Typically, a carrier can support and may also optionally mask a substrate during processing steps such as thin-film deposition. Thus, a substrate can be transferred through a processing system within the carrier. In other words, the carrier is transferred through the processing system while supporting a substrate.

[0013] According to typical embodiments, which can be combined with other embodiments described herein, a substrate can be a glass substrate, a metal substrate, a polymer substrate, or any other substrate suitable for material deposition. According to yet further embodiments, which can be combined with other embodiments described herein, substrates can be transferred through a processing system with an essentially vertical orientation or a horizontal orientation. Thereby, figures 2 to 9 would correspond to the top view if the substrates would be transported vertically and would correspond to a side view if the substrates would be transported horizontally.

[0014] Figure 1 illustrates a top view of a substrate processing system 100, wherein the substrates are moved vertically through the processing system. The substrates are moved into and out of the processing system through gate valves 112 and 114, respectively. Typically, load lock chambers (not shown in figure 1) can be provided for inserting or removing the carriers or substrates while maintaining a vacuum in the system. According to typically embodiments, as described herein, the term evacuated or maintaining a vacuum relates to providing reduced pressures in a vacuum chamber, e.g., below 1 mbar. The substrates can be moved into the first chamber 102 and can then have a continuous flow through chamber 104, chamber 105, chamber 106, and chamber 108 before the substrates are removed out of the processing system 100 through gate valve 114. Within the processing system 100 a transport device having rollers 122 is provided. The substrates can be supported by the rollers 122 and can thereby be supported in an essentially vertical position. Typically, the substrate position can deviate slightly from the vertical orientation such that the substrates are stably supported by the rollers 122. When entering the processing system 100 through gate valve 112, heating elements 124 can be provided in a first processing chamber 102. Figure 1 shows frontside and backside heating elements 124 in order to raise the temperature of the substrates as desired for a processing step in a subsequent processing chamber. In figure 2, the subsequent deposition step is shown to be a deposition or coating step, wherein coating unit 126 is provided for depositing a thin film on a substrate moving between the rollers 122 and the coating units 126. Chamber 105 is illustrated as a round chamber indicating that the substrates can be rotated within the chamber in order to be transferred from chamber 104 to chamber 106. Thereby, a robot or another substrate handling device can typically be provided within chamber 105 for transferring the substrates from one side of the processing system, i.e. the lower side in Fig. 1, to the other side of the processing system, i.e. the upper side in Fig. 1. Within chamber 106 a further deposition step such as a sputtering process can be conducted. This is exemplarily indicated by rotatable sputter cathodes 128. Chamber 108 can, for example, be used for providing a cooling down period for the substrates before leaving the processing system 100 through gate valve 114. [0015] Reference 103, which is shown in figure 1, indicates a wall of the chamber 102. Typically, the wall of the chamber 102 has an opening formed therein in order to allow the substrates to pass through the opening. Similar openings are provided in chambers 104, 105, 106 and 108. Figure 1 shows four gas separation devices 200 which separate the processing atmospheres of the adjacent chambers with respect to each other. Typical embodiments of gas separation devices are illustrated with respect to figures 2, 3, 4 A, 4B, 5, 6, 7, and 8 below. The gas separation devices adjust or switch the flow resistance of a processing gas in one of the adjacent process areas, particularly when the continuous flow of substrates cannot be guaranteed or the thickness of the opening filling element, which passes through the opening in the chamber wall 103, changes. According to typical embodiments described herein, a wall with an opening can either be a wall next to a subsequent chamber, i.e. an outer wall of a vacuum chamber, or can be an inner wall in a vacuum chamber, i.e. a wall separating the inner region of the vacuum chamber in different regions. In order to attain the necessary process stability, the flow resistance between the different processing areas is switchable, i.e. adjustable. This can be particularly useful if the vacuum condition, i.e., the pressure varies between the adjacent processing regions by at least one order of magnitude, typically by at least two orders of magnitude, and/or if the mixtures of processing gases in the adjacent processing regions are significantly different. This can be the case if, for example, reactive gases such as oxygen are used for one process and not the other process. For example, at least one of the processes in the adjacent processing areas, which are separated by the gas separation device according to embodiments described herein, can be a reactive sputter process. In light thereof, according to some embodiments, which can be combined with other embodiments described herein, the embodiments described herein can be utilized for coaters for electrochromic coated glass and for methods of manufacturing electrochromic coated glass.

[0016] Figure 2 shows a first embodiment of a gas separation device for separating a first processing region 1 and a second processing region 2. The chamber wall 103 has an opening 203. The chamber wall can, for example, be a wall of a vacuum chamber as shown in figure 1. As shown in figure 2, the carrier 3 with a substrate 4 provided therein, is passing through the opening 203 in the chamber wall 103 and through the gas separation device or the adjustable flow resistance control unit 201. The gas separation device includes a housing portion 210 and a movable portion 220. During the transfer of the carrier or substrate through the opening 203, a gap 291 exists between the wall 103 and the carrier. The gap is chosen to be sufficiently small in order to separate the first processing area from the second processing area. However, during an operation mode where no carrier is provided within the opening 203, the gap 291 corresponds to the opening 203 itself. Under such operating conditions, the movable portion 220 can be moved to adjust the flow resistance, which is, for example, shown in figure 3.

[0017] According to some embodiments, which can be combined with other embodiments described herein, the gas separation device 200 or the adjustable flow resistance control unit 201 can be provided such that another gap 292 exists between the gas separation device and the wall 103. Further, there exists a gap 294 between the carrier 3 and the housing portion 210 and a gap 293 between the housing portion and the movable portion 220. Yet, alternatively at least the gap 292 can be minimized such that the adjustable flow resistance control unit 201 is directly coupled or fixed to the wall 103. This is, for example, shown in figure 3. During an operation condition where no carrier is transferred through the gas separation device (see, e.g., figure 3) an opening 213 and an opening 223, which are provided in the housing portion 210 and the movable portion 220, respectively, provides the gas flow resistance . These openings have a cross-sectional area, which is not sufficiently small as to provide the desired gas separation. Thus, the movable portion 220 can be rotated such that the flow resistance of the gas through the adjustable flow resistance control unit 201 is adjusted or switched between at least two values. In light of the above, according to some embodiments, which can be combined with other embodiments described herein, a adjustable flow resistance control unit is provided to adjust the flow resistance or the gap conductance between the first processing region 1 and the second processing region 2.

[0018] According to one embodiment, the housing portion 210 can include a first housing portion 212 and a second housing portion 214. Thereby, it is possible to insert the movable portion 220 within the housing portion during manufacturing of the gas separation device. For the embodiments described with respect to figures 2 and 3, the movable portion is a rotatable gate with an opening 223 that is sufficient in size to allow the substrates or carriers pass therethrough. The housing portion 210 and the rotatable gate are configured to provide a sufficiently small gap therebetween. Typically, this gap can be as small as possible. However, friction between the housing portion and the movable portion needs to be considered, particularly if particle generation of undesired particles in deposition region needs to be considered. Thus, typically a small gap can be provided to minimize friction and particle generation, the material of the housing and the movable portion can be chosen such that friction and/or particle generation can be reduced or minimized, for example, if a gap-less design is desired. Therefore, typical examples of materials can be a metal, such as aluminum, aluminum alloys or stainless steel, can be plastics such as PEEK, or combinations of these materials can be used. According to typical embodiments, which can be combined with other embodiments described herein, the flow resistance or gap conductance, which separates the two processing regions, can be adjusted or can be switched between at least two values. According to typical embodiments, which can be combined with other embodiments described herein the gap 293 between the housing portion 210 and the movable portion 220 can be 0.1 mm or larger, typically 0.5 mm or larger, such as, for example, 1 mm or 2 mm.

[0019] Figure 3 illustrates the use of two adjustable flow resistance control units 201, which are described in more detail above, to form a gas separation device 300. Thereby, two adjustable flow resistance control units 201 are provided next to each other in order to elongate the duct or gap which is provided for having an increased flow resistance. Figure 3 illustrates an operation condition, where the movable portions of the flow resistance control unit are in the closed position respectively. Thereby, the flow resistance or gap conductance between the first processing area on the left-hand side of chamber wall 103 and the right-hand side of the second flow resistance control unit is mainly controlled by the gap 293 between the movable portion 220 and the housing portion 210.

[0020] According to yet further embodiments, which can be combined with other embodiments described herein, the two adjustable flow resistance control units 201, which are shown in figure 3, might be provided with a space therebetween, such that the duct is provided. Thereby, a vacuum pump can be connected to the duct between the two adjustable flow resistance control units and the area between the flow resistance control units can be evacuated in order to remove any residual gases which might have been diffused from one processing region in the direction of the other processing region. Depending on the processing steps conducted in the first processing region and the second processing region, such as duct could, according to yet further embodiments, also be used for introducing the sweep gas or the like.

[0021] Further embodiments are illustrated in figures 4A and 4B. An adjustable flow resistance control unit 400 is provided next to the chamber wall 120 having an opening 203. Typically, the opening 203 can be a slit opening, which is adapted for transfer of carriers or substrates therethrough. Accordingly, the vertical processing system, i.e. the processing system with a vertical substrate transport, corresponds to the top view shown in figures 4A and 4B, whereas the horizontal processing system, i.e. the processing system with a horizontal substrate transport, corresponds to the site view shown in figures 4A and 4B. The adjustable flow resistance control unit 400 includes the further opening 423 within the movable portion 420 of the adjustable flow resistance control unit. As shown in figures 4A and 4B, the movable portion 420 is a linear movable portion, which is also indicated by arrow 403. In order to move the movable portion from a closed position, i.e. an upper position in figures 4A and 4B, to an open position, i.e. a lower position in figures 4A and 4B, in which the opening 203 and the opening 423 essentially overlap, a lever arm 426 is provided. Typically, the level arm 426 can be connected to a linear drive unit for adjusting the flow resistance independent of the presence of a carrier or substrate. According to yet further optional modifications, the drive unit could generally be positioned outside of the vacuum camber. Thereby, access to the drive unit itself can be simplified.

[0022] As compared to the embodiment shown in figure 4A, the embodiments shown in figure 4B further includes a housing portion 410, wherein the housing portion 410 also has an opening 413. The housing portion 410 can be connected to the wall 103 to provide a guidance for the movable portion 420. According to some embodiments, which can be combined with other embodiments described herein, a gap is provided when the adjustable flow resistance control unit is in the closed position and when it is in an open position. Thus, according to typical embodiments, the gap conductance between the adjacent processing areas is not reduced to essentially zero as this would, for example, be the case for a vacuum valve. Further, the adjustable flow resistance control unit does not require excessive forces such as above 1000 N, i.e. the forces can be 500 N and below in order to bring the flow resistance control unit to the closed position, as might be, for example, desired for the deformation of an O-ring in a valve flap. Thus, the gas separation devices described herein allow for an easy and cost efficient separation of processing areas. According to typical embodiments, which can be combined with other embodiments described herein, the gap between the movable portion 420 and the chamber wall 103 or a gap between the housing portion 410 and the movable portion 420 can be at least 0.1 mm, or at least 0.5 mm, for example, 0.7 mm to 2 mm, such as about 1mm.

[0023] According to typical embodiments, which can be combined with other embodiments described herein, the gas separation can thereby be provided for, and the gas separation devices can be adapted for, a pressure difference between the first processing region and the second processing region of at least one order of magnitude, or even at least two orders of magnitudes and/or a difference in processing gases, wherein only one of the processing gases in the adjacent processing regions includes the gas selected from the group consisting of: a reactive gas, oxygen, nitrogen and mixtures thereof. For example, typical pressure differences can be a factor of 1: 10 and above, such as 1 :60. A typical separation factor between two processing regions can be at least 100 or at least 5000, such as, for example, a separation factor of about 10000. A separation factor is thereby determined such only the portion of the factor (e.g., only 1 of 10000 molecules) of a gas in one processing region can be detected in the other processing region.

[0024] Figure 5 shows another embodiment, which can be useful for understanding the invention. Therein, a flap 520 can be rotated around a rotation axis 521. The opening 220 in the wall 120 is covered when the adjustable flow resistance control unit is in a closed position. Thereby, typically a gap of at least 0.1 mm or at least 0.5 mm, for example, 0.7 mm to 2 mm, such as about 1 mm can be maintained between the flap 520 and the wall 103. Contrary to the use of a valve flap, which would generally require a sealing such as an O-ring, a rigid material of the movable portion, i.e., the flap 520, would be directly adjacent or closer to the wall 103. Further, the forces required to close the movable portion would be 1000 N or less or when referring to the moment of torque for the rotation below 200 Nm. In light thereof, an adjustable flow resistance control unit could be configured for varying the flow resistance of the gas between two processing regions wherein it is switched between two non-zero conductances. Thereby, the gap conductance or the flow resistance can also be adjusted for an operating condition where a carrier or substrate is transferred through an opening in the wall and through a gas separation device, and for the operating condition where no carrier or substrate is transferred through an opening in the wall and through a gas separation device. . [0025] According to yet further embodiments, which can be combined with other embodiments described herein, the adjustable flow resistance control unit can be provided by the housing portion 610 in the form of two guiding rails and the shutter 620, which can be moved from a first position to a second position. Thereby, the housing portion 610 includes an opening, which can have a size of at least the opening 203 in the wall 103. Typically, this opening can be provided between the two guiding rails. For example, a flexible belt or tape can be guided between the guiding rails of the housing portion 610, such that the flexible belt or tape is rolled onto roll 622 and can be moved up and down as shown in figure 6. According to typical examples, the flexible belt or tape can be made of steel, other metals, or other materials suitable for adjusting the flow resistance between two processing areas being in fluid communication through opening 203. Such an embodiment might be particularly useful if there is little space available in the region of the opening 203. The width of the guiding rails and the movable portion 620 can be designed to be relatively small and the roll 622 can be provided in an area, which is distant from the opening 203. Further, as already described with respect to figure 2 the drives for moving the belt, i.e., to wind up and wind out the belt, can be a rotary drive, which allows for simplified feedthrough of the rotating shaft from within the vacuum atmosphere to outside of the vacuum atmosphere in order to provide the rotary drive outside of the vacuum chamber. In light of the above, according to some embodiments, which can be combined with other embodiments described herein, a rotating drive for moving the movable portion of the adjustable flow resistance control unit might be beneficial if the drive is to be positioned outside of a vacuum chamber. [0026] According to yet further embodiments, the flow resistance control unit can also include a housing portion 710 with a slit or opening 713 therein and a movable portion 720, which can include at least one flap element, typically two flap elements. Thereby, a yet further opening for having substrates or carriers passing therethrough can be provided between the two flap elements of the movable portion 720. As shown with respect to figures 7 and 8, one adjustable flow resistance control unit or two adjustable flow resistance control unit can be provided adjacent to the opening in the wall 103. According to yet further optional modifications, which can be combined with other embodiments described herein, more than two adjustable flow resistance control units can also be provided. The two flow resistance control units shown in figure 8 have a spacing therebetween. Thereby a duct is formed, which allows the vacuum pumps 802 to evacuate the region between the two flow resistance control units. It is to be understood that the region needs to be connected to a vacuum pump with a suitable duct, which is not shown in figure 8. [0027] According to some embodiments, as described above, the movable portion of the adjustable flow resistance control units can be moved with a drive. Such a drive could be provided within the vacuum chamber or, for simplified access to the drive unit, outside of the vacuum chamber. Thereby, rotary drives might further simplify vacuum feedthroughs. Typically, these drives can be small and can be adapted for providing forces of 200 Nm and below, e.g., 20 Nm to 100 Nm, since no atmospheric pressure is applied and the housing portions and movable portions can be configured such they move frictionless with respect to each other, because a gap may remain for the first (closed) and second (open) position.

[0028] According to other embodiments, the movable portions of the flow resistance control units can also be spring-loaded or could have at least one other resetting element for switching the flow resistance control unit in one of the first position or second position. For such embodiments, at least one lever surface or at least one lever arm having a lever surface can be provided. Thereby, a substrate or carrier moving through the gas separation device and contacting the level arm lever surface can switch the adjustable flow resistance control unit in one position and the resetting element, such as a spring, can reset the adjustable flow resistance control unit to the other position. Figures 7 and 8 show movable portions 720 having two flap elements and a spring 725 between a flap and a corresponding housing portion. If a substrate or carrier moves through the gas separation device, in figures 7 and 8 from right to left, the movable portion 720 of the adjustable flow resistance control unit is contacted at a lever portion or surface portion of the flap and increases the distance between the two flap elements in order to allow trespassing of the carrier or substrate. After the carrier or substrate has passed through the gas separation device, the springs 725 switch the flow resistance control unit back to the closed position.

[0029] As shown in figure 9, a similar principle could also be applied for the embodiments shown in figures 2 and 3. The gas separation device 200 can be provided with an opening mechanism having a first roller 950, which is connected to the movable portion of the gas separation device, and two further rollers 954. A lever arm 952 is connected to one of the rollers 954. On impingement of the carrier 10 due to the movement as indicated by arrow 11, the lever arm 952 rotates the roller 954. The drive mechanism, which can, for example, be a belt 956 connecting the rollers 954 and the roller 950, rotates the roller 950 and, thereby, the movable portion of the gas separation device 200. As will be understood, similar principles can also be applied for other gas separation devices described herein. For example, a flap 520, which is shown in figure 5, could be opened by a carrier moving from left to right in figure 5, and could be back-switched or reset by a spring or another resetting element. As described above, a lever surface, i.e. a surface to apply a force to a lever, could either be provided by a surface portion of a lever arm or by a surface portion of the movable portion itself.

[0030] Typical embodiments of methods of operating a gas separation device, particularly the gas separation device according to embodiments described herein, include, for example three steps as shown in figure 10. In step 1002 a gas separation device or an adjustable flow resistance control unit is switched to an open position such that in step 1004 one or more substrates can be transferred from one processing area to another processing area through the gas separation device. Thereafter, the gas separation device is switched to a closed position in step 1006. According to typical embodiments, which can be combined with other embodiments described herein, a gap is provided between an opening in the wall and a carrier or substrate and between at least one opening in the gas separation device and the carrier or substrate. Typically, the gap size with a carrier or substrate being transferred is sufficiently small to allow for gas separation between the process areas. According to typical embodiments, which can be combined with other embodiments described herein, the openings, such as slits, can have a width which allows for the transfer of carriers having a thickness of 10 mm or above, 20 mm or above or even 30 mm or above, for example 25 mm to 32 mm. The widths of the openings in the housing portion and/or the movable portion of the adjustable flow resistance control unit are sized accordingly, for example, 12 mm or above 24 mm or above, for example 35 to 45 mm. When the gas separation devices are switched to a closed position in step 1006, the gap sizes, i.e. the gaps of the closed positions without a carrier in the gas separation device, can be similar in size to the gaps in the open position with a carrier being transferred through the gas separation device. Yet according to some embodiments, the gap sizes in the closed position might be reduced as compared to the gap sizes between the gas distribution device and the transferred substrate. However, even if the gap sizes might be 0.1 mm or smaller, no sealing, which might, e.g. require forces of at least 1000 N, would be provided. According to embodiments described herein, the flow resistance is controlled, i.e. limited, and/or the gap conductance is controlled, for example, between a value of essentially zero to 1200 l/(s*cm ² ).

[0031] As described herein, embodiments typically relate to providing a gas separation device for an opening through which a substrate or a carrier can be transferred. Thereby, it is typically referred to large-area substrates as described herein, e.g. having dimensions of at least 0.5 m, at least 1 m, at least 2 m or above. For example, typical substrate sizes can be 1.8 m x 3m. As compared to a tunnel or duct, wherein the gas separation, i.e. the gas flow resistance is increased, by the length of the duct or tunnel, the space consumption can be reduced because the gas flow resistance (proportional to the inverse of the gap conductance) can be adjusted depending on the operating conditions. As described herein, the gas flow resistance can be adjusted for the cases where a substrate is transferred and where no substrate is transferred. Further, the gas separation devices can be built into or fitted to existing chambers and no separate or additional modules or housings would be required. Typical separation factors can be 1:5 to 1: 10000, particularly even when large-area substrates are considered.

[0032] In light of the above, a plurality of embodiments has been described. According to one embodiment, a gas separation device for separating evacuated processing regions, wherein the processing regions are in fluid communication with each other by an opening in a wall, are provided. The gas separation device includes at least one adjustable flow resistance control unit configured for adjusting the gas flow resistance between the evacuated processing regions, wherein the at least one adjustable flow resistance control unit includes at least one further opening. According to typical optional modifications thereof the at least one further opening of the adjustable flow resistance control unit can essentially correspond to the opening in the wall. According to yet further alternative or additional modifications, the at least one further opening of the adjustable flow resistance control unit and the opening in the wall can be slits configured for allowing of a carrier or a substrate to pass therethrough; the carrier or the substrate can have at least a size corresponding to Gen 4, particularly wherein the slit has a cross-section with a ratio of a length to a height being at least 10: 1, more particularly the length being at least 1 m and the height being at least 0.1 m; and/or the device can further include a housing portion and a movable portion, wherein the movable portion is movable within the housing portion to provide a first gap when switched to a first position and a second gap when switched to a second position. According to yet further embodiments, which can be combined with other embodiments described herein, at least one of the housing portion and the movable portion can include the at least one further opening; the housing portion can have a first further opening of the at least one further opening and the movable portion has a second further opening of the at least one further opening; and/or the adjustable flow resistance control unit can be adapted to provide the first gap when the first further opening and the second further opening overlap with respect to each other and to provide the second gap when the first further opening and the second further opening are offset with respect to each other. According to typical examples, the movable portion can be a rotatable cylinder with the at least one further opening extending in an essentially radial direction through the cylinder; the movable portion can be a linear movable portion, which is movable along a first direction, wherein the at least one further opening is provided in the linear movable portion and extends in a direction, which is non-parallel to the first direction, particularly essentially perpendicular to the first direction, the housing portion can include at least two guide rails with the at least one further opening provided between the guide rails, and wherein the movable portion is a shutter movable between the guide rails, or the movable portion can include at least one flap element, particularly two flap elements, which is movably mounted in the at least one further opening provided in the housing portion. According to a yet further alternative or additional modification, the gas separation device can further include at least one lever surface adapted for switching the flow resistance control unit on impingement of a substrate or a carrier, and at least one resetting element adapted for back-switching the flow resistance control unit. [0033] According to another embodiment, a processing system for processing a substrate therein is provided. The processing system includes a first vacuum chamber providing a first processing region therein, a second vacuum chamber providing a second processing region therein, wherein at least one of the first vacuum chamber and the second vacuum chamber provides the wall having the opening therein, and at least one gas separation device according to any of the embodiments described herein, which is provided within the first vacuum chamber or the second vacuum chamber and which is provided adjacent to the opening in the wall. [0034] According to a yet further embodiment, a method of operating a gas separation device, particularly a gas separation device according to embodiments described herein is provided. The method includes switching the gas separation device to an open position, transferring one or more substrates or one or more carriers with substrates through the gas separation device and from a first evacuated processing region to a second evacuated processing region, wherein a first gap is provided when the one or more substrate or the one or more carriers are transferred through the gas separation device, and switching the gas separation device to a closed position after transfer of the one or more substrates or the one or more carriers such that a second gap is provided which has a flow resistance equal to or smaller than the first gap.

[0035] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.