WO2019207295A1

WO2019207295A1 - Sealing device

Info

Publication number: WO2019207295A1
Application number: PCT/GB2019/051134
Authority: WO
Inventors: Ben CLEMENTS; Trevor CLEMENTS; Steven DICKEN
Original assignee: Emerson & Renwick Ltd
Priority date: 2018-04-23
Filing date: 2019-04-23
Publication date: 2019-10-31
Also published as: GB202018266D0; GB2573110A; GB2588529A; GB201806585D0

Abstract

There is provided a sealing device for a substrate processing apparatus, the sealing device comprising: an outer body at least partially defining a passage for the transfer of a substrate therethrough, a sealing member configured to selectively obstruct the passage so as to form a substantially gas-tight seal in response to an input, wherein the sealing member is a substantially continuous loop peripherally surrounding the passage or surrounded by the passage.

Description

SEALING DEVICE

The present invention relates to a sealing device for a substrate processing apparatus, a substrate processing device comprising a sealing device, a method of forming a seal within a substrate processing device, and a method of operating a substrate processing device.

Technologies such as near field communications tags, flexible electronics and flexible displays often require the deposition of one or more layers of material onto a flexible substrate. Depending upon the technology, the deposition processes used to apply additional layers of material to the substrate may be adversely affected by the presence of contaminants in the atmosphere, such as, for example, water vapour or oxygen. To reduce the exposure of the materials to contaminants, it is often necessary to perform the deposition processes at a substantially reduced pressure, such as for example in a vacuum. Typically, the deposition processes are carried out within a substrate processing apparatus which is hermetically sealed from the atmosphere so as to permit the formation of a vacuum. Certain deposition processes may only be achievable in a vacuum, whilst other deposition processes which are achievable outside of vacuum can be improved when exposed to a vacuum.

Known substrate processing apparatuses comprise a winding chamber and a processing chamber separated by a partition wall. Normally, the substrate to be processed is wound upon a pair of spools positioned in the winding chamber. As the substrate is fed between the two spools, it passes into and out of the processing chamber, in which the deposition process is carried out, via a pair of passages formed in the wall. The wall typically comprises sealing devices which can be actuated to selectively seal the passages extending between the winding chamber and the processing chamber. Sealing is typically possible even when substrate is still disposed within the passage. The sealing devices mean that the winding chamber and the processing chamber can be isolated from one another such that vacuum can be maintained in one of the chambers whilst the other chamber is at atmospheric pressure. This may be particularly useful, for example, when one of the chambers requires maintenance or when the spools of substrate need replacement. Many deposition processes can only be conducted within a“medium” vacuum (less than 10³ mBar) or a“high” vacuum (less than 10⁶ mBar). At such vacuum levels, even a relatively small amount of leakage from the atmosphere can cause the pressure in the chambers to increase to unacceptable levels. When a vacuum is formed in only one of the winding and processing chambers, leakage of atmospheric air into the vacuum containing chamber will occur via the sealing device. It is therefore desirable to provide a sealing device which exhibits reduced leakage.

It is desirable to obviate or mitigate one or more of the disadvantages mentioned above. It is further desirable to provide an alternative sealing device, substrate processing apparatus, method of sealing, and method of operating a substrate processing apparatus.

According to a first aspect of the invention there is provided a sealing device for a substrate processing apparatus, the sealing device comprising: an outer body at least partially defining a passage for the transfer of a substrate therethrough, a sealing member configured to selectively obstruct the passage so as to form a substantially gas-tight seal in response to an input, wherein the sealing member is a substantially continuous loop peripherally surrounding the passage or surrounded by the passage.

In use, substrate is transferred from one chamber of a substrate processing apparatus to another through the passage of the sealing device. In order to permit substrate to move from one chamber to the other the passage of the sealing device must be relatively unobstructed. Because of this, space is available within the passage around the substrate for the transfer of gasses between the two chambers. In some circumstances, it is desirable to seal one chamber from the other such that the pressure of each chamber can be controlled independently. For example, by maintaining a vacuum in one of the chambers whilst the other chamber is at atmospheric pressure. Because the sealing member can selectively obstruct the passage, movement of gasses between the chambers can be prevented and the pressure within each chamber controlled separately.

By“selectively obstruct” it is meant that the sealing member is capable of moving or deforming such that in a first (unsealed) configuration transfer of substrate and gasses through the passage is permitted and in a second (sealed) configuration transfer of substrate and gasses through the passage is substantially prevented. The sealing member need not exclude the substrate from the passage, and, in particular, is preferably configured to obstruct the passage with the substrate in situ.

The substrate may be under tension as it passes through the sealing device. When the sealing member is obstructing the passage, friction between the sealing member and the substrate prevents the substrate from moving. As such, any tension in the substrate is maintained whilst the sealing member is obstructing the passage. This is particularly advantageous where substrate on a first side of the sealing device needs to be cut from substrate on a second side of the sealing device. New substrate can then be attached to the cut portion on the first side of the sealing device and re-tensioned, without affecting the tension of the substrate on the second side of the sealing device.

By“continuous loop” it is meant that the sealing member does not comprise terminal ends. As such, the only possible location for leakage to occur when the sealing member is in the sealed configuration is at the points where the sealing member contacts the substrate. In contrast, where a non-continuous type sealing member is used, it is also necessary to seal the terminal ends of that sealing member.

In this context, the term“peripherally surrounded” may mean that the sealing member extends around the entire perimeter of the passage. As such, the sealing member is able to seal substantially all of the passage between the substrate and the outer body. Where it is said that the sealing member is surrounded by the passage, what is meant is that, in an embodiment where the sealing device includes an inner body (see below), the sealing member may be located on the inner body such that the passage is outboard of the sealing member, the passage thereby surrounding the sealing member.

It is envisaged that some embodiments of the present invention may not include an inner body (as discussed below). In such embodiments the passage may be sealed by the sealing member expanding to the extent that it contacts itself, i.e. such that a first portion of the sealing member contacts a second portion of the sealing member, the first and second portions being spaced from one another when the sealing member is not expanded. The sealing device may further comprise an inner body peripherally surrounded by the outer body, the inner body being spaced apart from the outer body so as to define the passage therebetween. In this context, the term“peripherally surrounded” may mean that the entire perimeter of the inner body is surrounded by the outer body. As such, the passage may be generally annular in shape. In such arrangements, the seal may be formed between the sealing member and the inner body. The use of an inner body means that the radius of curvature of the sealing member can be made relatively large, and thus the likelihood of any kinks or creases occurring in the sealing member (which may be associated with an area of overly tight curvature) are reduced.

The sealing member may be expandable between an unsealed configuration in which passage of gas through the passage is permitted and a sealed configuration in which passage of gas through the passage is substantially prevented. In the unsealed configuration passage of the substrate through the passage may be permitted. In the sealed configuration the substrate may pass through the passage, but movement of the substrate through the passage may be substantially prevented. Because the sealing member is expandable, the sealing member itself may be the only moving part of the sealing device. As such, there is no requirement to provide ancillary components such as pistons-cylinder devices to control the movement of the sealing member. Thus the overall cost and complexity of the sealing device is reduced.

The sealing member may comprise a resiliently deformable material. Because the material of the sealing member is resiliently deformable, the sealing member is able to expand and contract in response to an input force. Examples of resiliently deformable materials suitable for the sealing member include silicon-based rubbers or vulcanised rubbers. Furthermore, the resilient nature of the sealing member means that the sealing member is able to conform to the contours of the inner and/or outer bodies and any substrate disposed in the passage so as to form a seal. Preferably, the resiliently deformable material is also a low-permeability and/or low-outgassing material.

The sealing member may comprise a hollow interior configured to receive a pressurised fluid. Because the interior of the sealing device can be pressurised, the pressure of the fluid within the interior can be used to control the expansion and/or contraction of the sealing member. The pressure of the fluid in the interior of the sealing member therefore provides the input force for controlling the configuration of the sealing member. For example, the sealing member can be placed in a sealed configuration by adjusting the pressure of the fluid so that it is higher than the pressure exterior the sealing member (e.g. the pressure of the adjacent chambers of the substrate processing apparatus). Likewise, the sealing member can be placed in an unsealed configuration by adjusting the pressure of the fluid so that it is lower than the pressure exterior to the sealing member (e.g. the pressure of the adjacent chambers).

The sealing member may comprise a sealing member port configured to place the interior of the sealing device in fluid communication with a pressure regulating system. The sealing member port allows the pressure of the fluid in the interior of the sealing member to be adjusted using the pressure regulating system. The pressure regulating system may be substantially any system capable of maintaining and/or adjusting the pressure of the fluid in the interior of the sealing member, and may optionally be used to regulate the pressure of the fluid in the chambers of the substrate processing apparatus. The pressure regulating system may include a source of negative pressure, a source of positive pressure and one or more valves to selectively connect the source of positive pressure and the source of negative pressure to at least one of the sealing member port and one of the chambers of the substrate processing apparatus. The pressure regulating system may selectively connect the source of positive pressure and the source of negative pressure to each of the chambers of the substrate processing apparatus and the sealing member port.

The outer body may comprise a groove configured to receive the sealing member. The groove is able to hold the sealing member in position so that in operating conditions where the pressure difference between the two chambers is large, the sealing member does not detach from the outer body. In some embodiments, the sealing member may be held in position using an interference fit, suitable fixing(s) and/or with the use of adhesive.

The inner body may comprise a groove configured to receive the sealing member. The groove is able to hold the sealing member in position so that in operating conditions where the pressure difference between the two chambers is large, the sealing member does not detach from the inner body. In some embodiments, the sealing member may be held in position using an interference fit, suitable fixing(s) and/or with the use of adhesive. The sealing member may be supported by the outer body. Because the sealing device is supported by the outer body, any control lines (such as for example fluid lines) can be directly connected to the sealing member. In some embodiments, the inner and/or outer body may include a gas flow passage through which the sealing port of the sealing member may be connected to a source of positive and/or negative pressure.

The sealing member may be a first sealing member and the sealing device may further comprise a second sealing member. The second sealing member may be identical to the first sealing member, and in particular, may have one or more of the optional features of the first sealing member listed above. In alternative embodiments, the sealing device may comprise substantially any number of sealing members, such as for example three or four sealing members.

In alternative embodiments, the first and second sealing members may have a different configuration. For example, the first sealing member may be supported by the outer body and the second sealing member may be supported by the inner body.

An intermediate zone may be defined between the first sealing member and the second sealing member. In addition, the sealing device may comprise an intermediate port in fluid communication with the intermediate zone and a pressure regulating system. The intermediate port may be defined by the outer body, or in embodiments comprising an inner body it may alternatively be defined by the inner body. When the sealing members are in their sealed configurations and one of the chambers is at low pressure and the other chamber is at a higher pressure, a small amount of fluid may leak from the higher pressure chamber to the low pressure chamber, via the sealing device. However, because the intermediate port is in communication with a pressure regulating system, the pressure regulating system can control the pressure of the fluid in the intermediate zone. In particular, the pressure regulating system can be operated to extract fluid which has leaked past one of the sealing members. As such, the sealing device is able to maintain a steady pressure in the low pressure chamber, by substantially preventing leakage from the high pressure to the low pressure chamber via the intermediate zone. According to a second aspect of the invention there is provided a substrate processing apparatus comprising a first chamber and a second chamber separated by a wall, wherein the wall comprises a sealing device according to the first aspect of the invention.

During use of the substrate processing apparatus, substrate may be passed between the first and second chambers via the sealing device, and, in particular, via the passage of the sealing device. For example, one chamber may be a winding chamber and the other chamber may be a processing chamber. As described above, the sealing device is able to form a substantially gas-tight seal between the first and second chambers so that the pressure in either chamber can be independently controlled.

In some embodiments, the substrate may be passed from the first chamber to the second chamber through a first portion of the passage of the sealing device, and from the second chamber to the first chamber through a second portion of the passage of the sealing device.

For example, during use it may be required to maintain both chambers at vacuum pressures. When one of the chambers needs to be accessed, it is normally necessary for both chambers to be brought back up to atmospheric pressure. However, by using a sealing device according to the first aspect present invention, vacuum can be maintained in whichever one of the chambers the user does not need access to. As such, vacuum only needs to be regenerated in one of the chambers (and not both) after accessing the relevant chamber. Therefore the amount of down time and cost associated with regenerating a vacuum after it has been necessary to access one of the chambers is reduced.

The sealing device may be a first sealing device and the wall may further comprise a second sealing device. In such an arrangement, the substrate may be passed from the first chamber to the second chamber through the first sealing device (and, in particular, via the passage of the first sealing device) and from the second chamber to the first chamber through the second sealing device (and, in particular, via the passage of the second sealing device. The precise positioning of the passages between the first and second chambers may be dependent upon the nature of the substrate used, an in particular the geometry or materials of the substrate. By having two sealing devices, the substrate processing apparatus can accommodate greater variations in the position of the passages between the first and second chambers. For example it is possible to space the passages for traversing the wall further away from one another than by using a single sealing device (for example, due to the structural limitations regarding the size of the sealing member). As such, providing two sealing devices allows for improved versatility in the positioning of the passages between the first and second chambers. Furthermore, by using two sealing devices rather than only a single sealing device, the pressure of the sealing members of each sealing device can be controlled independently from one another. This provides greater control and adjustability for each seal.

According to a third aspect of the invention, there is provided a method of forming a seal between a first chamber and a second chamber in a substrate processing apparatus, the method comprising: providing a sealing device including a passage in a wall of the substrate processing apparatus separating the first chamber and the second chamber; arranging a sealing member within the passage in a substantially continuous loop; actuating the sealing member so as to obstruct the passage to form a substantially gas-tight seal.

It will be appreciated that a number of the advantages set out above with respect to the first aspect of the invention apply equally to the third aspect of the invention. In particular, the sealing member is able to form an effective seal between the first and second chambers whether a substrate is located within the passage or not.

The method may further comprise forming the sealing member from a resilient material, providing the sealing member with a hollow interior, and adjusting the pressure of a fluid contained in the interior of the sealing member so that it is higher than the pressure of the environment to the exterior of the sealing member. In particular, the pressure of a fluid contained in the interior of the sealing member may be adjusted so that it is higher than the pressure of one of the first or second chambers. Because the pressure of the fluid in the interior of the sealing member is higher than the pressure of the environment to the exterior of the sealing member (e.g. the pressure of one of the chambers), the sealing member will expand so as to obstruct the passage and form the seal. When both the first and second chambers are at the same pressure, the pressure of the fluid in the interior of the sealing member may need to be higher than the pressure in both chambers in order to expand and form the seal. When one of the chambers is at a low pressure and the other chamber is at a high pressure, the pressure of the fluid in the interior of the sealing member may need to be the same or higher than the pressure of the more highly pressurised chamber.

According to a fourth aspect of the invention there is provided a method of operating a substrate processing apparatus comprising forming a seal according to the third aspect of the invention.

It will be appreciated that any of the optional features discussed above in relation to one aspect of the present invention may, where appropriate, be applied to any of the other aspects of the present invention.

Figure 1 is a schematic diagram of a substrate processing apparatus according to the present invention;

Figure 2 is a schematic top view of a sealing device according to the present invention in an unsealed configuration;

Figure 3 is a schematic partial cross-sectional side view of a sealing device according to the present invention in an unsealed configuration;

Figure 4 is a schematic top view of a sealing device according to the present invention in a sealed configuration;

Figure 5 is a schematic partial cross-sectional side view of a sealing device according to the present invention in a sealed configuration; and

Figure 6 is a schematic diagram of a pressure regulating system for the substrate processing apparatus of the present invention.

Figure 1 shows a substrate processing apparatus 2 comprising a housing 4 divided into a winding chamber 6 and a processing chamber 8 by a partition wall 10. A first end of a flexible substrate 12 is wound upon a first spool support 14 to form a first spool 16. A second, opposite, end of the substrate 12 is wound upon a second spool support 18 to form a second spool 20. The first and second spools 16, 20 are positioned in the winding chamber 6. A pair of sealing devices 22, 23 are positioned in the partition wall 10. The sealing devices 22, 23 define a passage (described below) through which the substrate 12 can pass to move between the winding chamber 6 and the processing chamber 8. The path of the substrate 12 as it passes through the sealing devices 22, 23 is shown by dashed lines. The sealing device 22 is preferably identical to the sealing device 23.

During use, the substrate is fed along a substrate path from the first spool 16 through a first one of the sealing devices 22, 23 and into the processing chamber 8 where it is processed by one or more processing units 24. After processing, the substrate 12 is fed along the substrate path through a second one of the sealing devices 23, into the winding chamber 6 and onto the second spool 20. In some embodiments, the substrate 12 can be fed in either direction between the first spool 16 and the second spool 20. Processing of the substrate 12 may comprise adding material to the substrate 12 using any suitable technique. Such techniques include but not limited to: physical vapour deposition (including thermal evaporation, electron beam or sputtering processes), chemical vapour deposition (including plasma-enhanced chemical vapour deposition), atomic layer deposition, reactive ion etching, plasma treatment (including micro- or radio-frequency treatment using a linear ion source), curing (including ultraviolet, thermal or photonic curing), or the like. In Figure 1 , the processing physics are indicated schematically by divergent lines 25.

The winding chamber 6 and the processing chamber 8 are connected to a pressure regulating system via ports formed in the housing 4 (described below). In many applications, the processing of the substrate 12 must be conducted in a vacuum. Typically, this requires that at least the processing chamber 8 is maintained at either a “medium” vacuum (less than 10³ mBar) or a“high” vacuum (less than 10⁶ mBar).

With reference to Figure 2, the first sealing device 22 comprises an outer body 26, an inner body 28 and a first sealing member 30. The outer body 26 defines an inner wall 27 and the inner body 28 defines an outer wall 29, the inner and outer walls 27, 29 being positioned to face one another and define a seal space therebetween in which the first sealing member is located. The outer body 26 and the inner body 28 of the sealing device 22 are composed of a solid material such as stainless steel or aluminium. The outer body 26 is a generally oval-shaped ring having a hollow interior defined by the inner wall 27. The inner body 28 is received within the hollow interior, such that entire perimeter of the inner body 28 is surrounded by the outer body 26, and, in particular, by the inner wall 27. The inner body 28 is held in position by a bridge (not shown) connected to the outer body 26, the partition wall 10, and/or the housing 4. The bridge may be located at any appropriate position, provided it does not obstruct the path of the substrate 12 passing through the sealing device 22. The outer perimeter of the inner body 28 defined by the outer wall 29 is also generally oval-shaped, such that an inner wall 27 of the outer body 26 and an outer wall 29 of the inner body 28 are complementarily shaped. The sealing device 22 comprises a passage 32 between the inner wall 27 of the outer body 26 and the outer wall 29 of the inner body 28, such that the passage 32 is generally annular in cross-section. The separation between the inner and outer walls 27, 29 which define the passage is substantially constant, and, in one example, is typically about 6 to 12 mm. The thickness of the substrate, in one example, is typically 1 to 200 pm.

The inner and outer walls 27, 29 define opposing generally planar sections 27a, 29a which are joined at either end by generally arcuate surfaces 27b, 29b. During use, the substrate 12 extends through the part of the passage 32 defined between the opposing planar sections 27a, 29a of the inner and outer walls 27, 29. In particular, the substrate passes through the passage 32 in a parallel direction relative to the planar sections 27a, 29a of the outer and inner bodies 26, 28 (that is to say, in a direction normal to the cross-sectional view of Figure 2). In other words, the substrate path is generally perpendicular to the normal to each of the planar sections 27a, 29a, and, furthermore, is generally parallel to the surface of the planar sections 27a, 29a.

As shown in Figure 3, in addition to the first sealing member 30, the sealing device 22 comprises a second sealing member 31 located in the seal space. The first sealing member 30 is positioned in a first groove 34 of the outer body 26, and the second sealing member is positioned in a second groove 35 of the outer body 26. The first and second grooves 34, 35 and the first and second sealing members 30, 31 are, in the present embodiment, substantially identical. Although, this need not be the case. The first and second grooves 34, 35, and hence the first and second sealing members 30, 31 , are spaced from one another in a direction parallel to the direction of travel of the substrate through the sealing device, in use - that is to say, they may be said to be located one over the other. Typically, the first and second sealing members 30, 31 are retained in the grooves 34, 35 by an interference fit, but may optionally or alternatively be secured using an adhesive. The sealing members 30, 31 and grooves 34, 35 extend around the entire perimeter of the outer body 26 such that each sealing member 30, 31 and groove 34, 35 is substantially continuous. Each sealing member 30, 31 comprises a hollow interior which is connected to the pressure regulating system via a pair of ports 36. The first sealing member 30 is spaced apart from the second sealing member 31 to define an intermediate zone 33 therebetween. The intermediate zone 33 is also connected to the pressure regulating system via a port 37 defined by the inner wall 27 of the outer body 26.

The sealing members 30, 31 are composed of a flexible, resilient material such that the sealing members 30, 31 are able to expand and contract in response to the pressure of a fluid in their interiors. The material of the sealing members 30, 31 must also be able to resist leakage of gas through the material itself, and therefore is preferably made from a low-permeability and/or low-outgassing material. Preferably, the sealing members 30, 31 are made from silicon-based rubbers, however other suitable materials for the sealing members 30, 31 include vulcanised rubbers.

As discussed in more detail below, in use, the sealing members each create a seal by having their interiors supplied with pressurised fluid such that they expand to contact both the inner and outer walls 27, 29 (and substrate) so as to prevent a gas leak path between the inner and outer walls 27, 29 from above the sealing device to below the sealing device (e.g. from the winding chamber to the processing chamber).

The sealing members 30, 31 are substantially continuous such that they are similar in character to an O-ring. The sealing members 30, 31 are preferably manufactured as a continuous loop, such that the need to create a bond anywhere along the body of the sealing members 30, 31 is avoided. As such, the profile of the sealing members 30, 31 is free from dislocations and/or surface defects such that optimum sealing can be achieved. The fluid in the interior of the sealing members 30, 31 may be a liquid or a gas, for example air, nitrogen or any inert gas, such as for example argon.

The unsealed state of the sealing device 22, as shown in Figures 2 and 3, is defined by contraction of the sealing members 30, 31. In their contracted state, the sealing members 30, 31 are spaced apart from the outer wall 29 of the inner body 28 such that they do not contact the substrate 12 as it passes through the passage 32. So as to cause the sealing members 30, 31 to contract, the pressure of the fluid inside the sealing members 30, 31 may be the same or less than the pressure of the environment to the exterior of the sealing members (e.g. the winding chamber 6 and/or the processing chamber 8).

Figures 4 and 5 show the sealing arrangement 22 in a sealed state in which the sealing members 30, 31 are expanded so that, as well as bearing against the inner wall 27, they bear against the outer wall 29 of the inner body 28. Expansion of the seal members 30, 31 substantially blocks the passage 32 between the inner and outer walls 27,29 thus isolating the winding chamber 6 from the processing chamber 8. As shown most clearly in Figure 5, the sealing members 30, 31 force the portion of the substrate 12 in the passage 32 against the outer wall 29 of the inner body, thus holding the substrate 12 in compression therebetween. Due to friction between the substrate 12 and the sealing members 30, 31 , when the sealing members 30, 31 are in their sealed position, movement of the substrate 12 is substantially prevented. This holding of the substrate in place may, in certain applications, be beneficial. For example, holding the substrate in place whilst changing at least one of the substrate spools ensures that i) the substrate stays in position such that when the machine is restarted the processing unit processes the substrate from the point at which it left off, and ii) the tension within the substrate is maintained whilst the machine is stopped.

As shown in Figure 4, the sealing members 30, 31 flex around the edges of the substrate 12 so that the seal is formed with the substrate 12 in situ. That is to say, due to their resilient materials, the sealing members 30, 31 are able to conform to the contours of the substrate 12 when located against the outer wall 29. It is possible that small gaps 40 could be formed along the edges of the substrate 12. However, due to the resilience of the sealing members 30, 31 the size of such gaps 40 is minimal. For the sake of clarity, the gaps 40 shown in Figure 4 have been exaggerated in size. It will be appreciated that the depth of the gaps 40 will be defined by the thickness of the substrate 12, and therefore the size of the gaps 40 will be no more than 1 to 200 pm.

With reference to Figure 6, the substrate processing apparatus 2 comprises a pressure regulating system 42. Preferably, the pressure regulating system 42 is configured to individually control the pressure of the winding chamber 6, processing chamber 8, sealing members 30, 31 and the intermediate zone 33. An embodiment of such a pressure regulating system is described below, however it will be appreciated that any suitable pressure regulating system may be used for controlling pressure in different parts of the substrate processing apparatus 2.

The pressure regulating system 42 comprises a negative pressure source 44 and a positive pressure source 46. The negative pressure source 44 is configured to supply a pressure below atmospheric pressure and the positive pressure source 46 is configured to supply a pressure the same or greater than atmospheric pressure. In the case where the positive pressure source is configured to supply atmospheric pressure, the positive pressure source may be the atmosphere itself. The negative pressure source 44 is fluidly connected to the winding chamber 6 and the processing chamber 8 via first and second fluid lines 48, 50 respectively. The negative pressure source 44 is fluidly connected to the intermediate zone 33 via a third fluid line 52. Each of the first, second and third fluid lines 48, 50, 52 has a valve V1 , V2, V3 disposed therein which is configured to regulate the flow of fluid along that line. Vacuum can be applied to the winding chamber 6 and the processing chamber by opening the valves V1 and V2. Likewise vacuum can be applied to the intermediate zone 33 by opening the valve V3.

Both the negative pressure source 44 and the positive pressure source 46 are connected to the first and second sealing members 30, 31. In particular, the negative pressure source 44 is fluidly connected to the first and second sealing members 30, 31 via a fourth fluid line 54. The fourth fluid line 54 comprises a pair of valves V4 configured to regulate the flow of fluid through the fourth fluid line 54. The positive pressure source 46 is fluidly connected to the fourth fluid line 54 via a fifth fluid line at a position between the valve V4 and the sealing members 30, 31. The fifth fluid line 56 comprises a valve V5 configured to regulate the flow of fluid through the fifth fluid line 56. Vacuum can be applied to the first and second sealing members 30, 31 by opening valve V4, so as to maintain the sealing members 30, 31 in their unsealed configuration. When it is desired to expand the sealing members 30, 31 so that they are in their sealed configuration, valve V4 is closed so as isolate the sealing members 30, 31 from the negative pressure source 44, and valve V5 is opened so as to expose the sealing members 30, 31 to the positive pressure source 46. So as to ensure that the substrate 12 can move freely between the winding chamber 6 and the processing chamber 8, during processing of the substrate 12 the sealing devices 22, 23 are maintained in their unsealed configurations. Any gas present in the substrate processing apparatus 2 may therefore pass through the sealing devices 22, 23 between the winding chamber 6 and the processing chamber 8. As such, during processing of the substrate 12 it is necessary to apply vacuum to both the winding chamber 6 and the processing chamber 8 using the pressure regulating system 42, for example by opening valves V1 and V2. In order to cause the sealing members 30, 31 to remain in their unsealed configuration, the pressure of the fluid in the interior of the sealing members 30, 31 may be equal to or less than the vacuum within the winding chamber 6 and the processing chamber 8. As such, the valve V4 of the pressure regulating system is opened and the valve V5 is closed so as to expose the interior of the sealing members 30, 31 to the same pressure as the winding chamber 6 and the processing chamber 8.

With reference to Figure 1 , in some circumstances the user may require access to the interior of one of the winding chamber 6 or processing chamber 8. For example, the user may need to access the winding chamber to unload a processed substrate, or load more unprocessed substrate; or may need to access the processing chamber to carry out maintenance. Access to the chambers 6, 8 is typically provided by removing a section of the housing 4 in the vicinity of the relevant chamber 6, 8 or may be provided by a door or port (not shown). When the interior of one of the chambers 6, 8 is to be accessed, it is necessary, in order to avoid potentially dangerous re-pressurisation, for the relevant chamber to be brought up to atmospheric pressure. This may occur by connecting the relevant chamber to the positive pressure source. Accordingly, increasing the pressure in the relevant chamber 6, 8 destroys the vacuum in that chamber 6, 8 and enables opening up of the housing 4. If the sealing devices 22, 23 are maintained in their unsealed configuration, it may be necessary to destroy the vacuum in both the winding chamber 6 and the processing chamber 8. Once the vacuum has been destroyed in both the winding chamber 6 and the processing chamber 8, the amount of energy and time required to reduce the pressure in the winding chamber 6 and the processing chamber 8 back to the required vacuum level (known as“pump-down”) is relatively large, and can increase the cost of processing the substrate 12. As such, it is desirable to maintain vacuum conditions in whichever one of the chambers 6, 8 the user does not require access to, so that only the chamber the user requires access to is re-pressurised and subsequently requires pump down.

In such situations, the sealing devices 22, 23 are actuated so as to isolate the winding chamber 6 from the processing chamber 8, so that one of the winding chamber 6 and the processing chamber 8 can be brought up to atmospheric pressure and safely opened to the atmosphere. In order to maintain the sealing devices 22, 23 in their sealed configurations, the pressure in the interior of the sealing members 30, 31 may be the same as or greater than the exterior of the sealing members 30, 31. That is to say the pressure in the sealing members may be greater than the pressure in the open chamber (e.g. atmospheric pressure). A positive difference in pressure between the interiors of the sealing members 30, 31 and the chambers 6, 8 will urge the sealing members 30, 31 to expand, thus blocking the passage 32 and forming the seal. However, if the pressure of the interiors of the sealing members 30, 31 is less than that of the environment exterior to the sealing members (e.g. the open chamber 6 or 8) the (negative) difference in pressure between the open chamber 6 or 8 and the interiors of the sealing members 30, 31 will urge the sealing members 30, 31 to contract. The quality of the seal provided may therefore be affected by fluctuations of the pressure in the winding chamber 6. In order to avoid such an occurrence, in some embodiments the sealing members 30, 31 are pressurised above atmospheric pressure, for example by using positive pressure source 46 which is at above atmospheric pressure.

The situation above may occur, for example, when processing of the substrate 12 is completed and the processed substrate 12 needs replacing. At the end of processing, most of the substrate 12 will be wound upon the second spool 20 and the first spool 16 will be largely depleted. To replace the substrate 12, firstly the sealing devices 22, 23 are actuated by closing valve V4 to shut off the negative pressure source 44, and opening valve V5 to expose the sealing members to the positive pressure source 46. This causes the sealing members 30, 31 to expand and form a seal against the inner body 28 with the substrate 12 in situ, as shown in Figures 4 and 5. In doing so, the sealing members 30, 31 isolate the winding chamber 6 from the processing chamber 8. As such, when the winding chamber 6 is opened, the vacuum is in the processing chamber is unaffected. Once the winding chamber 6 is open, the substrate 12 is cut at two positions, namely: (i) between the first spool 16 and the first one of the sealing devices 22, 23, and (ii) between the second spool 20 and the second one of the sealing devices 22, 23. Under the action of the sealing devices 22, 23, the portion of the substrate 12 within the processing chamber 8 remains in situ. A new first spool 16 is placed upon the first spool support 14 and is attached to the portion of the substrate 12 extending from the first sealing device 22 (for example by using an adhesive). A new second spool 20 is placed upon the second spool support 18 and is attached to the portion of the substrate 12 extending from the second sealing device 23. The winding chamber 6 is closed, and then pumped down such that its internal vacuum pressure is equal to the vacuum pressure of the processing chamber 8. The sealing devices 22, 23 are then returned to their unsealed configurations by closing the valve V5 and opening the valve V4 (causing the sealing members 30, 31 to contract) so that processing of substrate 12 can resume.

In some applications, the substrate 12 must be held in tension whilst it is passing through the processing chamber 8. Due to friction between the substrate 12 the sealing members 30, 31 , the contact force exerted by the sealing members 30, 31 on the substrate 12 prevents movement of the substrate 12 through the passage 32. As such, when the sealing devices 22, 23 are actuated, the tension in the substrate 12 is maintained even when the spools of substrate 16, 20 in the winding zone are being replaced. When fresh substrate is subsequently attached to the remaining portion of the substrate 12 in the processing chamber 8, the spool supports 14, 18 can be adjusted so as to exert a tension on the fresh substrate 12 which matches the tension of the substrate in the processing chamber. When the sealing members 22, 23 are returned to their unsealed configurations, the tension across the entire length of substrate 12 will be unaffected. As such, the need to re-tension the substrate 12 in the processing chamber 8 is avoided.

Compared to previous sealing devices, the benefit of the sealing devices 22, 23 of the present invention is that when the sealing devices 22, 23 are in their sealed configurations, there are only two possible positions at which leakage can occur. This is namely at the edges of the substrate 12, as shown by gaps 40 in Figure 5. Because the sealing members 30, 31 are continuous loops, when they are in their sealed configurations, there are no other positions along the sealing members 30, 31 through which leakage can occur. In contrast, where a non-continuous sealing member is used, leakage gaps will form both along the edges of the substrate and at the terminal ends of the sealing members (for example, where they are connected to a housing).

It will be appreciated that over time the pressure of the vacuum in the processing chamber 8 will increase as gasses leak into the processing chamber 8 from the outside environment. This “pressure creep” is dependent upon a large range of factors, including for example the materials, volume and surface area of the processing chamber 8, and the presence of any leaks elsewhere in the chamber. However, as set out above, the size of the gaps 40 is typically very small, and therefore any change in pressure directly attributable to fluid flow through the gaps 40 is negligible. However, in order to further reduce the effect of gas leakage through the gaps 40, vacuum pressure is also applied to the intermediate zone 33 via the port 37. The port 37 is therefore able to remove leaked gas before it passes beyond the second sealing member 31 , so as to improve the sealing performance of the sealing devices 22, 23. However, if any gas does pass beyond the second sealing member 31 and into the processing chamber 8, this gas will be removed via the second fluid line 50 under the vacuum applied by the negative pressure source 44 (see Figure 6).

In alternative embodiments of the invention, the sealing device 22, 23 may comprise a more than two sealing members, or may comprise only a single sealing member. The sealing members 30, 31 and grooves 34, 35 may both be positioned in the inner body 28, or may be positioned so that one of the sealing members 30, 31 is in the inner body 28 and the other of the sealing members 30, 31 is in the outer body 26. Furthermore, in certain embodiments two sealing members may be used in opposition to one another such that they are configured to contact one another so as to form the seal.

Rather than having two sealing devices 22, 23, the substrate processing apparatus may instead comprise a single sealing device 22. In this case, the substrate 12 can be passed through both portions of the passage 32 (see Figures 2 and 3) defined between the corresponding planar portions of the inner and outer walls. That is to say, in such an embodiment, the substrate passing from the winding chamber to the processing chamber may pass through a first portion of the passage which is defined between first corresponding planar portions of the inner and outer walls, and the substrate passing from the processing chamber to the winding chamber may pass through a second portion of the passage which is defined between second corresponding planar portions of the inner and outer walls. The inner and outer bodies 28, 26 of the sealing devices 22, 23 can have substantially any shape provided the passage 32 formed therebetween is capable of receiving and transferring substrate 12 between two chambers and providing the shape is compatible with the use of one or more sealing member which has a continuous loop configuration (i.e. no ends).

Claims

CLAIMS:

1. A sealing device for a substrate processing apparatus, the sealing device comprising:

an outer body at least partially defining a passage for the transfer of a substrate therethrough,

a sealing member configured to selectively obstruct the passage so as to form a substantially gas-tight seal in response to an input,

wherein the sealing member is a substantially continuous loop peripherally surrounding the passage or surrounded by the passage.

2. A sealing device according to claim 1 , further comprising an inner body peripherally surrounded by the outer body, the inner body being spaced apart from the outer body so as to define the passage therebetween.

3. A sealing device according to any preceding claim, wherein the sealing member is expandable between an unsealed configuration in which passage of gas through the passage is permitted and a sealed configuration in which passage of gas through the passage is substantially prevented.

4. A sealing device according to claim 3, wherein the sealing member comprises a resiliently deformable material.

5. A sealing device according to claim 3 or 4, wherein the sealing member comprises a hollow interior configured to receive a pressurised fluid.

6. A sealing device according to claim 5, wherein the sealing member comprises a sealing member port configured to place the interior of the sealing device in fluid communication with a pressure regulating system.

7. A sealing device according to any preceding claim, wherein the outer body comprises a groove configured to receive the sealing member.

8. A sealing device according to any preceding claim wherein the sealing member is supported by the outer body.

9. A sealing device according to any preceding claim, wherein the sealing member is a first sealing member and the sealing device further comprises a second sealing member.

10. A sealing device according to claim 9, wherein an intermediate zone is defined between the first sealing member and the second sealing member, the sealing device comprising an intermediate port in fluid communication with the intermediate zone and a pressure regulating system.

11. A substrate processing apparatus comprising a first chamber and a second chamber separated by a wall, wherein the wall comprises a sealing device according to any preceding claim.

12. A substrate processing apparatus according to claim 11 , wherein sealing device is a first sealing device and the wall further comprises a second sealing device.

13. A method of forming a seal between a first chamber and a second chamber in a substrate processing apparatus, the method comprising:

providing a sealing device including a passage in a wall of the substrate processing apparatus separating the first chamber and the second chamber;

arranging a sealing member within the passage in a substantially continuous loop;

actuating the sealing member so as to obstruct the passage to form a substantially gas-tight seal.

14. A method of forming a seal according to claim 13, wherein the method further comprises:

forming the sealing member from a resilient material,

providing the sealing member with a hollow interior, and

adjusting the pressure of a fluid contained in the interior of the sealing member so that it is higher than the pressure of the environment to the exterior of the sealing member.

15. A method of operating a substrate processing apparatus comprising forming a seal according to claim 13 or 14.