TECHNICAL FIELD

[0001] Embodiments relate to reduction of contamination in substrate processing systems and/or substrate processing apparatuses. Embodiments further relate to trapping of contaminants and/or cleaning of a carrier at or within a vacuum processing system. Embodiments particularly relate to a particle trapping device, a particle removal device, a transportation system, a load lock chamber and a vacuum processing system.

BACKGROUND

[0002] Substrates are often coated, for example, in vacuum coating plants, under high- vacuum conditions, at pressures within the range of 5*10' ⁴ hPa to 0.5 hPa. In order to increase the plant productivity and to avoid the need of having to evacuate the entire installation for each substrate and, especially, the high-vacuum section, load and unload locks are used for the substrates.

[0003] For example, in flat panel display production, particles, both from mechanical components of the processing system and the process as such, are a main factor for yield loss. Accordingly, the wish for less contamination during a vacuum process has increased in recent years. Particle contamination may for instance occur if the transport system or components in the process system produce particles during the process, if the substrate to be processed introduces particles into the evacuated process system, and the like. For example, mechanical friction, e.g. during transportation of a substrate carrier or a substrate respectively, may cause particle generation. There is a plurality of possible contamination particle sources in the deposition system during operation, which influences the product quality. [0004] Cleaning and exchanging components as well as continuous vacuum pumping in the process system is a way to reduce the contamination risk of the product. As stated above, the process is beneficially performed in the fastest possible and most efficient way. Cleaning and exchanging procedures take time for maintenance, which reduces production time.

[0005] For example, in a physical vapor deposition (PVD) system, the substrate can be transported with a moving substrate carrier. The substrate carrier can be in rolling contact with multiple support rollers. The tribological wear from the contact zone leads to particle release and to particle generation. Device yield loss can be caused when the particles land on a substrate, for example, as an on-film defect. The reduction of particles that may negatively impact the substrate processing results in a yield improvement and, in turn, a commercial benefit.

[0006] Reducing the number of particles that impact substrate processing can be provided by a) reducing particle generation and b) trapping or collecting the generated particles such that the particles may not impact the substrate processing. Trapping the particles, such as transport particles, enables to reduce pre- and post- deposition particle adders onto the substrate as well as consecutive particle induced defect formation and yield loss. The improvement on killer defects, especially from metallic conductive particles, exhibits a large lever, as improvement of yield for one production system by 1%-point can easily provide large revenue opportunities.

[0007] In view of the above, it is beneficial to provide a particle reduction device, an improved load lock chamber, an improved vacuum processing system, and an improved method of transporting and/or cleaning a carrier in a vacuum processing system.

SUMMARY

[0008] According to the invention, a carrier cleaning head according to claims 1 to 8, a substrate processing system according to claims 9 to 11, a method of maintaining a substrate processing system according to claim 12, and a method of manufacturing a device according to claim 13 are provided. [0009] According to one embodiment, a roller for a carrier transport assembly is provided. The roller includes a roller body being rotatable and having a substrate support surface; a roller casing surround at least a portion of the roller; and a trapping surface of the roller casing, the trapping surface having at least a first surface portion facing the roller.

[0010] According to one embodiment, a substrate processing system is provided. The substrate processing system includes a carrier transport assembly having a plurality of rollers arranged along a transport direction of the carrier transport assembly, each roller of the plurality of rollers being a roller according to embodiments of the present disclosure.

[0011] According to one embodiment, a method of maintaining a substrate processing system is provided. The method includes removing a plurality of roller casings from a plurality of rollers of a carrier transport assembly; cleaning or removing a trapping surface of each of the plurality of roller casings; and assembling the plurality of rollers by providing a roller casing for each of the rollers.

[0012] According to one embodiment, a method of manufacturing a device is provided. The method includes transporting a carrier supporting a substrate with a carrier transport assembly having a plurality of rollers, the transporting including a rotation of a roller body for each of the rollers; trapping particles generated at the roller in a roller casing having a trapping surface; and processing or depositing one or more thin film layers of the device.

[0013] According to one embodiment, a carrier cleaning head for cleaning a carrier moving along a transport direction is provided. The carrier cleaning head includes a cleaning head body having a first conduit and a second conduit; two or more pairs of brushes, each pair of brushes having a first brush at a first side and a second brush at a second side, opposing the first side, the pairs of brushes being arranged along the transport direction; a first opening assembly in fluid communication with the first conduit and being configured to provide a purge gas; and a second opening assembly in fluid communication with the second conduit and being configured for particle removal.

[0014] According to one embodiment, a substrate processing system is provided. The substrate processing system includes a first vacuum chamber having a first wall; and a carrier cleaning head according to embodiments of the present disclosure, the carrier cleaning head being arranged adjacent the first wall, particularly outside of the first vacuum chamber.

[0015] According to one embodiment, a method of maintaining a substrate processing system is provided. The method includes removing a plurality of brushes of two or more pairs of brushes from a cleaning head body of a carrier cleaning head; cleaning the plurality of brushes; and assembling the carrier cleaning head by providing clean brushes.

[0016] According to one embodiment, a method of manufacturing a device is provided. The method includes transporting a carrier supporting a substrate into a substrate processing system having load lock chamber; trapping particles adhering to the carrier with a carrier cleaning head according to embodiments of the present disclosure; and processing or depositing one or more thin film layers of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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:

[0018] FIG. 1 shows a view of a transport system for conveying a carrier according to embodiments described herein;

[0019] FIG. 2 shows a schematic cross section view of a carrier transport system that can be utilized with embodiments described herein; and

[0020] FIG. 3 shows a perspective view of a roller assembly of a transport system, for example, a transport system shown in FIGS. 1 or 2, and including a particle reduction device according to embodiments of the present disclosure;

[0021] FIG. 4 A shows a perspective view of a roller assembly of a transport system, for example, a transport system shown in FIGS. 1 or 2, and including a particle reduction device according to embodiments of the present disclosure; [0022] FIG. 4B shows a perspective view of a roller assembly of a transport system, for example, a transport system shown in FIGS. 1 or 2, and including a particle reduction device according to embodiments of the present disclosure;

[0023] FIG. 5 shows a schematic view of a particle reduction device according to embodiments described herein, particularly a particle removal device, and having a brush for cleaning of a carrier, gas nozzles and a suction port;

[0024] FIG. 6 shows a schematic view of a particle reduction device according to embodiments described herein, particularly a particle removal device, and having a brush for cleaning of a carrier, gas nozzles and a suction port;

[0025] FIGS. 7A and 7B show an enlarged view of a particle reduction device according to embodiments described herein and as, for example, shown in FIG. 5 and/or 6;

[0026] FIG. 8 shows a portion of a vacuum processing system a including a particle trap according to embodiments described herein, the particle trap including rollers having a trapping surface at a roller casing and a carrier cleaning head;

[0027] FIG. 9 shows a flowchart illustrating methods of maintaining a substrate processing system and including replacement of brushes of the carrier cleaning head and replacement of carrier casings having a trapping surface according to embodiments of the present disclosure; and

[0028] FIG. 10 shows a flow chart illustrating methods of manufacturing a device including particle trapping according to embodiments of the present disclosure to reduce the number of particles impacting substrate processing.

[0029] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. DETAILED DESCRIPTION OF EMBODIMENTS

[0030] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in the figures. Generally, only the differences with respect to individual embodiments are described. Further, 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 description includes such modifications and variations.

[0031] According to embodiments of the present disclosure, apparatuses and methods are provided that enable reducing the number of particles that may impact the substrate processing. According to some embodiments, particles are trapped after generation of the particles. According to yet further, additional or alternative embodiments, particles are removed from a carrier and trapped after generation of the particles. As compared to other concepts aiming for the reduction of particle generation, embodiments of the present disclosure relate to trapping of particles after generation of the particles.

[0032] According to some embodiments, a method and device for particle trapping during substrate transportation in a PVD system is provided. Particles generated in a substrate transportation system, for example, a roller for supporting a carrier, are attracted to a predetermined location. Particles can, thus, be prevented from landing on a substrate, for example, a glass substrate. The mechanical trapping mechanism at a rolling contact zone can be provided.

[0033] According to some embodiments, methods and devices for in-situ cleaning and particle removal of particles from a carrier in a PVD system is provided. Particles adhering to, for example, a carrier can be removed from the carrier and attracted to a predetermined location. Particles can thus be prevented from landing on a substrate, for example, a glass substrate. For example, a cleaning device for particle removal from each moving carrier can be provided.

[0034] Accordingly, trapping of particles can result in a reduced number of particles that may negatively impact substrate processing. Yet further, additionally or alternatively, maintenance can be simplified and, thus, product maintenance time can be reduced. Cleaning procedures during product maintenance may be simplified due to the trapping of particles at the predetermined location.

[0035] FIG. 1 shows a carrier 10 supported by rollers 100 of a carrier transport assembly. The carrier 10 can include a frame 12. For example, the frame 12 can include one or more frame bars. Further, the carrier 10 can include a plurality of clamps 11. The clamps 11 support a substrate 13 at the carrier 10. According to some embodiments, which can be combined with other embodiments described herein, the carrier 10 can include a rod 14. The rod 14 can have a cylindrical cross-section. According to some embodiments, which can be combined with other embodiments described herein, the carrier may also include a bar or a rail, for example, a flat rail. The rod, rail or bar is provided at one or more of the frame bars and is configured for contacting the one or more rollers 100 of the carrier transport assembly. In the example shown in FIG. 1, the rod, rail or bar is attached to the frame, e.g., by one or more connecting elements such as connecting bridges.

[0036] A carrier transport assembly can include a plurality of rollers 100. Two rollers are exemplarily shown in FIG. 1. The rollers 100 may support the weight of the carrier 10 or at least a portion of the weight of carrier 10 (see also FIG. 2). Further, the rollers 100 can be configured to convey the carrier along a transport direction. For example, the rollers can be driven to rotate and/or to move the carrier along the transport direction. The rollers 100 include a roller body 102. The roller body 102 is rotatable around an axis. Further, the rollers include a substrate support surface 104. According to some embodiments, the substrate support surface 104 can be a cylindrical surface. According to yet further embodiments, which can be combined with other embodiments described herein, the substrate support surface can be shaped to be concave. A concave shaped substrate support surface 104 may correspond to a cylindrical shape of a rod 14 as exemplarily shown in FIG. 1. A substrate support surface being shaped to include a recess, for example, a recess along the perimeter of the roller body 102 can at least partially accommodate the rod or bar. Accordingly, the carrier 10 can be guided along the transport direction by the contact surface.

[0037] The roller 100 includes a roller casing 110. The roller casing 110 surrounds at least a portion of the roller and particularly the substrate support surface 104 of the roller 100. The roller casing includes a trapping surface 112. FIG. 1 shows two trapping surfaces 112. At least one trapping surface of the roller casing 110 faces the roller and, particularly the substrate support surface of the roller. The trapping surface 112 can trap particles released from the roller. For example, particles can be trapped by a magnetic force, an adhesive, by a mechanical labyrinth, and/or by an electrostatic force.

[0038] FIG. 2 is a schematic cross section view of carrier transport system 200 including a track assembly 210 according to embodiments described herein. FIG. 2 shows a schematic front view of carrier transport assembly and a carrier according to embodiments described herein. The carrier transport system 200 is configured for transportation of a carrier 10. The carrier may carry a substrate or mask in a transport direction in a vacuum chamber. The transport direction T is perpendicular to the paper plane of FIG.1. The carrier 10 has an essentially vertical orientation V during the transport (e.g., a vertical orientation +/-10 ⁰ ).

[0039] Some embodiments described herein involve the notion of the carrier being transported in a “vertical or near-vertical orientation” or an essentially vertical orientation. A vertical orientation of carrier 10 in the context of the present disclosure refers to carrier 10 being aligned to extend in a direction substantially parallel to the direction along which the force of gravity is oriented, i.e. substantially parallel to vertical direction Y. A nearvertical orientation may be defined as an orientation which deviates from exact verticality (the latter being defined by the gravitational force) by an angle of up to 15 degrees. In a vertical or near-vertical orientation, the carrier may support a substrate in a vertically standing or near- vertically standing orientation. Similarly, an essentially horizontal orientation may have a deviation of up to 15 degrees from horizontal.

[0040] According to embodiments described herein, the track assembly 210 includes the first passive magnetic unit 220 extending in the transportation direction T. As shown in FIG. 2, the first passive magnetic unit is configured to be on top of the carrier. The first passive magnetic unit 220 has a first magnetic pole and a second magnetic pole. According to embodiments described herein, the apparatus for vacuum processing of a substrate can include a carrier 10 configured to support a substrate or mask. The carrier 10 can include the first passive magnetic unit 20 on top of the carrier as shown in FIG. 2. The first passive magnetic unit 20 can have a first magnetic pole and a second magnetic pole. The magnet poles of the carrier and of the track assembly may both be vertically arranged or may both be horizontally arranged. Accordingly, lateral stabilization can be provided. The first passive magnetic unit 20 of the carrier is configured to magnetically couple with the first passive magnetic unit 220 of the track assembly. For example, the north pole of the first passive magnetic unit of the track assembly may face the south pole of the first passive magnetic unit of the carrier and vice versa.

[0041 ] According to embodiments described herein, the track assembly 210 includes the second passive magnetic unit 222 extending in the transportation direction T. The second passive magnetic unit 222 has a third magnetic pole and a fourth magnetic pole. The carrier 10 further includes a second passive magnetic unit 22 having a third magnetic pole and a fourth magnetic pole. The second passive magnetic unit 22 of the carrier is configured to magnetically couple with the second passive magnetic unit 222 of the track assembly. The third magnetic pole and the fourth magnetic pole of the carrier are the opposite poles of the third magnetic pole and the fourth magnetic pole of the track assembly. Accordingly, the magnetic force between the second passive magnetic unit of the carrier and the second passive magnetic unit of the track assembly is an attractive force in the counter direction of the gravitation force.

[0042] As shown in FIG. 2, the second passive magnetic unit 222 of the track assembly may be configured to be on the side of the carrier 10 being coupled with the second passive magnetic unit 22 of the carrier 10. The second passive magnetic unit 222 of the track assembly is configured to counteract the at least 60% of the weight of the carrier and partially levitate the substrate carrier.

[0043] According to embodiments described herein, the first passive magnetic unit of the track assembly and the second passive magnetic unit of the track assembly are configured to counteract at least the weight of a carrier or more. The magnetic levitation provided from coupling the first passive magnetic unit of the track assembly and the first passive magnetic unit of the carrier together with the magnetic levitation provided from coupling the second passive magnetic unit of the track assembly and the second passive magnetic unit of the carrier, counteracts at least 70%, particularly at least 90% of the carrier weight, more particularly 100% or more.

[0044] According to embodiments of the present disclosure, the weight of the carrier, particularly an essentially vertically oriented carrier is supported by the first passive magnetic unit at the top of the carrier, the second magnetic unit oriented towards the bottom of the carrier, i.e. vertically below the first passive magnetic unit and the rollers. A downward pulling force of the drive assembly is further counteracted by the first passive magnetic unit at the top of the carrier, the second magnetic unit oriented towards the bottom of the carrier, i.e. vertically below the first passive magnetic unit and the rollers.

[0045] During processing of a substrate, the carrier may be heated. Accordingly, there is a thermal expansion. Particularly for vertically oriented or essentially vertically oriented substrates, wherein the substrates may have a vertical height of 1 m or above or even up to several meters, i.e. large area substrates, the thermal expansion can be significant. Accordingly, it is beneficial if the second passive magnetic unit, i.e. the passive magnetic unit below the first passive magnetic unit at the top of the carrier, counteracts a majority of the weight of the carrier. The amount of thermal expansion at the position of the second passive magnetic unit is less as compared to the amount of thermal expansion adjacent to the first passive magnetic unit. Accordingly, the supporting forces of the passive magnetic units are less impacted by thermal expansion at the position of the second passive magnetic unit.

[0046] FIG. 2 shows the second passive magnetic unit at a vertical position between the rollers and the first passive magnetic unit. According to some embodiments, which can be combined with other embodiments described herein, the second passive magnetic unit may also be provided vertically below the rollers. The second passive magnetic unit and the rollers can be vertically close to each other in order to reduce the effect of thermal expansion. For example, the second passive magnetic unit and the rollers may have a vertical distance that is 20% or less of the vertical carrier dimension, particularly 10% or less of the vertical carrier dimension, more particularly 5% or less of the vertical carrier dimension.

[0047] According to embodiments described herein, the carrier 10 has a first rail, e.g. a top rail 204, configured to be in contact with an upward oriented portion of a substrate support surface of the at least one of the plurality of rollers 100. The carrier 10 further includes the second rail, e.g. a bottom rail 206. The second rail may be configured to be in contact with the downward oriented portion of a substrate support surface of the at least one of the pluralities of the rollers 100. According to some embodiments, which can be combined with other embodiments described herein, a gap can be provided between the second rail and the bottom of the rollers. For example, the gap can be 1 mm or less, such as 0.5 mm or less or even less than 0.3 mm. The distance between the first rail and the second rail is slightly larger than the diameter of the rollers, e.g. by 1 mm or less, such as 0.5 mm or less or even less than 0.3 mm.

[0048] According to embodiments described herein, the resultant force of the weight, the magnetic levitation forces, the pulling downward force generated by drive assembly 230 and the third passive magnetic unit can be 30% of the carrier weight or less, for example 20 % or less, such as 10% or less. The resultant force is supported by the at least one of the pluralities of rollers 100. The top of the at least one of the plurality of rollers is configured to be in contact with the first rail to be able to compensate the resultant force. The at least one of the plurality of rollers 100 carry the resultant force and overcome instability of magnet pairs in the vertical direction. The minimized contact surface between carrier and track assembly as well as minimizing the weight on the rollers significantly lowers the particle generation due to transportation. In the event of an upward resulting force during, for example, some operation conditions, the carrier can contact the second rail, e.g. the bottom rail 206. A roller casing 110 is shown by a dashed line in FIG. 2. A roller casing may be provided before and/or in front of roller body 102 in the transport direction and is, thus, illustrated with a dashed line.

[0049] Embodiments of the present disclosure with a roller casing having a trapping surface provide a particle trap function that allows for in situ particle trapping to a predetermined location, i.e. the trapping surface. The trapping surface is provided at the roller casing or roller housing. Accordingly, upon replacement of the roller casing or roller housing during product maintenance, particles can be removed from a substrate processing system. Experiments could show that 80% or more of the particles generated at a roller can be trapped at the roller casing. Further, particle trapping at the roller can be provided during atmospheric conditions and under vacuum conditions. According to some embodiments, which can be combined with other embodiments described herein, trapping concepts can include magnetic trapping, trapping with adhesion, for example, by an adhesive, and mechanical labyrinth trapping, wherein the mechanical labyrinth prevents escape of particles. Accordingly, particles that may have an impact on a substrate processing can be reduced. Furthermore, the predetermined location at which the particles are trapped at the roller casing results in low effort during product maintenance. [0050] FIG. 3 shows a roller 100. The roller 100 has a roller body 102 with a substrate support surface 104. A roller casing 110 surrounds at least a portion of the roller and provides a trap for particles. For example, particles can be generated during contact of a rail of a carrier and the substrate support surface 104 of the roller body 102. Some embodiments of the present disclosure, as exemplarily shown in FIG. 3, provide a magnetic trap for ferromagnetic particles. The roller casing 110 includes one or more trapping surfaces 112. At least the first surface portion faces the roller body 102. The roller casing can include a magnet housing, for example, with a plurality of openings 312 and 314. A magnet 320 is provided in the magnet housing. For example, the magnet 320 can be a permanent magnet having a magnet surface.

[0051] According to some embodiments, which can be combined with other embodiments described herein, the magnet housing can be made of magnetic material, particularly a ferromagnetic material. Accordingly, the magnet 320 is fixed relative to the magnet housing 315. Thus, vibrations during operation of the carrier transport assembly do not result in movement of the magnet 320 within the magnet housing 315. Particles are not released from the particle trap due to undesired movement.

[0052] Particles released during contact between the substrate support surface 104 and a rail or rod of a carrier are trapped to the magnet and the magnet housing. Particularly, ferromagnetic particles can be attracted by an attracting force of the permanent magnet. According to some embodiments, which can be combined with other embodiments described herein, the roller casing may include a first magnet housing and a first magnet on a first side of the roller in transport direction T and a second magnet housing and a second magnet on a second side of the roller in transport direction T. An upper side and a lower side of the roller are not surrounded by the roller casing to allow for a substrate support surface for a top rail and a bottom rail of the carrier.

[0053] The magnet housings 315 shown in FIG. 3 include a first side and a second side facing in transport direction T. The openings 312 can be provided at the first side and the second side. Particularly, the openings 312 are provided at a side of the respective magnet housing facing the roller body 102. The first side and the second side can be vertical sides of the magnet casing. According to some embodiments, which can be combined with other embodiments described herein, further openings 314 can be provided in the magnet housing at a third side and a fourth side of the magnet housing. The third side can be provided between the first side and the second side. The fourth side can be provided between the first side and the second side. The third side and the fourth side of the respective making housing can be horizontal sides.

[0054] According to some embodiments, which can be combined with other embodiments described herein, the trapping surface can include a magnet surface of the magnet 320 and can include a surface of the magnet housing. Particularly for ferromagnetic magnet housings, the magnetic attracting forces generated by the magnet 320 are also provided by the surface of the magnet housing. The openings 312 and the further openings 314 allow for trapping of particles, which are released from the roller during rotation of the roller due to the centripetal force of particles present at the roller during rotation of the roller. Tests durations with a roller casing having a trapping surface being equivalent to 1 /i years of operation of a carrier transport assembly proved efficient particle trapping, particularly for the trapping of ferromagnetic particles with a magnetic attracting force. For example, an amount of about 80% of the particles could be trapped during testing of a roller casing according to embodiments of the present disclosure.

[0055] According to one embodiment, a roller for a carrier transport assembly is provided. The roller includes a roller body being rotatable and having a substrate support surface and a roller casing which surrounds at least a portion of the roller. The roller further includes a trapping surface of the roller casing, the trapping surface having at least a first surface portion facing the roller. For example, the trapping surface includes a magnet housing. The magnet housing can be configured to house a magnet, particularly a permanent magnet. According to some embodiments, which can be combined with other embodiments described herein, the magnet housing can include a plurality of openings and/or the magnet housing can be made of a magnetic material, particularly a ferromagnetic material.

[0056] Yet further, additionally or alternatively, the trapping surface may include a magnet surface of a permanent magnet. According to some embodiments, which can be combined with other embodiments described herein, the roller casing can include a first magnetic trap at a first radial orientation of the roller and a second magnetic trap at a second radial orientation of the roller, wherein the second radial orientation is different from the first radial orientation. The roller casing surrounds at least a portion of the roller, for example, by having two or more magnetic traps at different sides of the roller and/or by having a trapping surface partially surrounding the substrate support surface of the roller body.

[0057] According to some embodiments, which can be combined with other embodiments described herein, additionally or alternatively, the trapping surface may include an adhesive, and electrostatic surface, and/or a mechanical labyrinth to trap the particles at the roller casing. FIG. 4 shows a roller 100 having a roller casing 110. The roller body has a substrate support surface 104. A portion of the roller casing is provided with a trapping surface including an adhesive. According to some embodiments, which can be combined with other embodiments described herein, the adhesive can be an adhesive mat, i.e. a sticky mat, an adhesive tape, or another adhesive. According to embodiments of the present disclosure, the trapping surface can have an area of 50 cm ² or above for one roller of the carrier transport assembly. Having, for example, 5 to 15 rollers contacting a carrier configured to support a substrate, a trapping surface of 250 cm ² to 750 cm ² can be provided.

[0058] According to some embodiments, which can be combined with other embodiments described herein, a vacuum compatible grease can be provided as a trapping surface of the roller casing. Utilizing a vacuum compatible grease allows for good desorption characteristics for substrate processing under vacuum conditions.

[0059] FIG. 4A shows a roller having a roller casing that may beneficially be utilized for a carrier transport assembly as illustrated in FIG. 1. For a carrier transport assembly as illustrated in FIG. 2, a roller 100 as shown in FIG. 4B can be utilized. The roller casing includes a first portion on a first side of the roller body 102 and the second portion on an opposite side of the roller body 102. A substrate support surface 104 is provided at an upper portion and lower portion of the roller body 102 to contact an upper rail and a lower rail of a carrier. A trapping surface 112, for example with an adhesive, such as a vacuum compatible grease, can be provided at a portion of the trapping surface facing the roller body 102.

[0060] Embodiments of the present disclosure relate to trapping of particles at a predetermined position for a substrate processing system. Trapping of the particles reduces the number of particles impacting the substrate processing. Additionally or alternatively, trapping the particles at a predetermined location reduces maintenance effort, since the particles can be removed by cleaning the trapping location. Some embodiments of the present disclosure relate to a roller having a roller casing with a trapping surface. Particularly particles generated at the contact surface of the roller and the carrier can be trapped with the roller casing. According to additional or alternative embodiments, particles adhering to the carrier can be trapped. For example, particles can be trapped before a carrier enters a vacuum processing system, i.e. upon transport of a carrier into a load lock chamber of a substrate processing system.

[0061] According to one embodiment, a carrier cleaning head for cleaning a carrier moving along a transport direction is provided. The carrier cleaning head includes a cleaning head body having a first conduit and a second conduit and two or more pairs of brushes, each pair of brushes having a first brush extending in a first direction, for example, in an inclined manner relative to the first direction, and a second brush extending in a second direction, for example, in an inclined manner relative to the second direction, the second direction being opposite the first direction, the pairs of brushes being arranged along the transport direction. The first direction may be upward and the second direction may be downward. The brushes may be included with respect to an upward or downward direction but can still be considered to extend upward or downward. The carrier cleaning head includes a first opening assembly in fluid communication with the first conduit and being configured to provide a purge gas and a second opening assembly in fluid communication with the second conduit and being configured for particle removal.

[0062] FIG. 5 shows a carrier cleaning head 500, particularly a carrier cleaning head for a carrier as exemplarily illustrated in FIG. 2. The carrier 10 includes a top rail 204 and a bottom rail 206. A portion 504 of a carrier body is provided between the top rail 204 and the bottom rail 206, particularly between the rails in the vertical direction. Particles that may adhere to the carrier, particularly to the rails of the carrier, may be removed from the carrier by the carrier cleaning head 500. Carrier cleaning is provided while the carrier is transported past the carrier cleaning head.

[0063] According to implementations of a carrier cleaning head, a combination of brushing, purging and suction for particle removal is combined. For example, purging can be provided as purging with clean dry air (CD A), i.e. as the CD A purge. According to some embodiments, which can be combined with other embodiments described herein, a cascade cleaning concept of multiple brushes, particularly, of multiple pairs of brushes can be provided. A pair of brushes may include a first brush or a first brush pad for the top rail 204 and a second brush or a second brush pad for the bottom rail 206. The cascade arrangement of the carrier cleaning head provides two or more brushes or pairs of brushes along the transport direction of the carrier. According to some embodiments, which can be combined with other embodiments described herein, four, six or eight flat bushes can be provided in two rows, e.g. an upper row and a lower row. One or more openings for particle removal, for example, through a suction port allows for trapping of the particles. The number of particles impacting the substrate processing can be reduced and the effort for product maintenance can be reduced.

[0064] FIG. 5 shows a carrier cleaning head 500, the carrier cleaning head including a cleaning head body 510. The cleaning head body 510 supports the first brush 522 and a second brush 524. The first brush and the second brush form a pair of brushes 520. The first brush is directed to clean the top rail 204. The second brush 524 is directed to clean the bottom rail 206. The cleaning head body 510 includes a first conduit 512. The first conduit 512 is connected to a gas line 518 for providing a purge gas. The purge gas can be, for example, a CDA purge gas. The cleaning head body further includes a second conduit 514. The second conduit 514 is configured for particle removal and is connected to a suction port 519. For example, the suction port 519 can be connected to a pump.

[0065] The carrier cleaning head provides an in-situ method for cleaning a carrier, and particularly for the removal of particles adhering to the carrier. The in-situ cleaning is provided for a moving carrier. The particles are trapped. The cleaning head body 510 can be provided in a system and may be provided for an existing system without impacting the production process.

[0066] According to some embodiments, which can be combined with other embodiments described herein, the carrier cleaning head provides a plurality of pairs of brushes. For example, two, three, four, or five pairs of brushes can be provided along the transport direction of the carrier. The pairs of brushes are provided in a cascade arrangement.

[0067] FIG. 6 shows a detailed view of a portion of the carrier cleaning head. The cleaning head body 510 is spaced apart from the top rail 204 of the carrier by a gap Gl. Similarly (not shown in FIG. 6) the cleaning head body 510 is spaced apart from the bottom rail 206 by a gap. According to some embodiments, which can be combined with other embodiments described herein, the cleaning head body is further spaced apart from a portion 504 of the carrier being arranged between the top rail and the bottom rail of the carrier. FIG. 6 shows a gap G2 illustrating the space between the cleaning head body 510 and the portion 504 of the carrier. According to some embodiments, one or more further openings 622 can be provided in the cleaning head body. The one or more further openings 622 face the portion 504 of the carrier and are in fluid communication with the second conduit for particle removal.

[0068] The spokes 620 or bristles of a brush are inclined relative to a vertical orientation and a horizontal orientation. The inclination is illustrated by an angle a in FIG. 6. For example, the angle a can be 30° to 75°. The length of the spokes 620 is longer than the gap Gl, particularly longer than the gap G1 along the direction of the spokes. Accordingly, the spokes provide the pressing force to the carrier rail. According to some embodiments, which can be combined with other embodiments described herein, the spokes of the brush and/or the brush is compressed. The length of the spokes that would provide an overlap depth without defamation of the spokes, can result in an overlap depth of 2 mm or above. The inclination of the spokes further provides cleaning of the carrier rail in an area of the gap G2 between the cleaning head body 510 and the portion 504 of the carrier. For example, the portion 504 of the carrier can extend vertically and/or parallel to a substrate support surface of the carrier. Due to the inclination of the spokes of the brush, a comer between the rail of the carrier and the body of the carrier, for example, at the portion 504 of the carrier, can be reached by the brush for particle removing. According to some implementations, which can be combined with embodiments of the present disclosure, the gap Gl and the gap G2 can be between 3 mm and 6 mm.

[0069] According to some embodiments, spokes of the pairs of brushes or the bristles of the pairs of brushes can be inclined with respect to the transport direction and are inclined with respect to a direction perpendicular to the transport direction. Further, additionally or alternatively, a first brush of a pair of brushes is arranged at a first side of the cleaning head body, for example at a top side and facing a top rail of the carrier. A second brush of a pair of brushes is arranged at a second side of the cleaning head body, for example, at a bottom side, i.e. the second side opposite the first side and facing the bottom rail of the carrier. The cleaning head body can further include a third opening assembly with one or more third openings (i.e. one or more further openings 622) arranged in the carrier head body at a third side, the third side being arranged between the first side and the second side.

[0070] According to yet further implementations, which can be combined with other embodiments described herein, a brush can be made of a conductive material or can be coated with a conductive material. A brush can include a brush pad and spokes attached to the brush pad. By having a conductive material or a conductive coating, electrostatic discharge (ESD) during brushing can be reduced or avoided. The spokes, i.e. the bristles of brush, have antistatic characteristics. According to some implementations, the brush pad can include a conductive material, for example, aluminum or the like.

[0071] FIGS. 7A and 7B show a portion of a cleaning head body 510. A plurality of brushes 522 are arranged along the transport direction T. Accordingly, upon movement of the carrier along the carrier cleaning head, a portion of a rail, bar or rod of a carrier is subsequently cleaned by the brushes. A brush includes a brush pad 722 and spokes 724. For example, two rows of spokes can be attached to a brush pad. The spokes of adjacent rows of spokes can be offset with respect to each other. The entire surface of a rail can be cleaned.

[0072] A carrier cleaning head includes a first opening assembly with openings 710. The openings 710 are in fluid communication with the first conduit and provide a purge gas in the direction of the brushing area. The first opening assembly can be provided between a first brush 522 and a second brush 524, particularly along the transport direction. FIG. 7A shows a top view of the carrier cleaning head. Corresponding brushes and corresponding openings 710 are provided at a bottom side of the cleaning head body 510. A brush at the top side and a corresponding brush at the bottom side form a pair of brushes according to embodiments of the present disclosure.

[0073] A carrier cleaning head includes a second opening assembly with openings 712. The openings 712 are in fluid communication with the second conduit. The second conduit can be connected to a suction port for removal of the particles during cleaning of the carrier. Openings 712 of the second opening assembly can be arranged between brushes along the transport direction. Further, additionally or alternatively, openings 712 can be arranged between rows of spokes at one brush 522. As exemplarity shown in FIG. 6, one or more third openings 622 can be provided, e.g. as vertical slits to remove particles adhering to the vertical plane of the carrier, i.e. a carrier portion between the top and bottom rail.

[0074] As illustrated in FIG. 7B, a brush 522 can be removed from the cleaning head body 510. The brush pad 722 of the brush 522 can be connected to the cleaning head body 510 with a clamping mechanism, which may for example be based on screws. During maintenance, a carrier cleaning head having three pairs of brushes can be maintained by removing six brushes and replacing the six brushes with cleaned or fresh brushes.

[0075] As described above, a carrier cleaning head includes a first opening assembly in fluid communication with the first conduit and is configured to provide a purge gas, and a second opening assembly in fluid communication with the second conduit is configured for particle removal. According to some embodiments, the first opening assembly and a second opening assembly can be arranged between two brushes along the transport direction. The first opening assembly can be oriented to direct purge gas to at least a pair of brushes of the two or more pairs of brushes. A pair of brushes can include two brush pads removably coupled to the cleaning head body. Additionally or alternatively, each brush of a pair of brushes includes rows of spokes and the rows of spokes are offset with respect to each other in a direction perpendicular to the transport direction.

[0076] A carrier cleaning head according to embodiments of the present disclosure provides a small distance of the openings of the first opening assembly relative to the workpiece to be cleaned. Accordingly, the ratio of the flow speed of purge gas at the nozzle or opening relative to the distance can be high even for comparably low flow speeds. For example, the distance of the openings of the first opening assembly to the workpiece can be 15 mm or below. Accordingly, a ratio of the flow speed and the distance can be 330 [1/s] or more at comparably low flow speeds. A consumption of a purge gas, for example, CD A, can be reduced. Yet further, the ratio between purge gas flow and the suction capacity can be improved. Having a higher suction capacity as compared to purge gas flow increases the cleaning effectiveness. For example, a suction capacity can be between 200 m ³ /h and 300 m ³ /h. According to some implementations, which can be combined with embodiments described herein, the suction capacity can be at least two times, particularly at least three times the flow of the purge gas. [0077] A carrier cleaning head according to embodiments of the present disclosure combines brushing, purging and suction to remove particles from the rail surface of the rail of a carrier. Purging, for example, with CDA and suction, enables continuous particles removal and may further enable brush cooling.

[0078] FIG. 8 shows a substrate processing system 800. The substrate processing system 800 includes a front end module 802. The front end module provides carriers and substrates, respectively, into the one or more vacuum chambers of the substrate processing system. FIG. 8 shows a first vacuum chamber 804 being a load lock chamber. Further, a second vacuum chamber 806 being a production chamber or processing chamber is provided. One or more carriers are removed from the front end module 802 into the load lock chamber. One carrier 10 is exemplarily shown in FIG. 8. Further, substrate processing station 850 or a substrate processing tool are exemplarily shown in FIG. 8. For example, the processing modules can be deposition sources, for example, PVD sources, such as rotatable sputter cathodes. According to other implementations, substrate processing station 850 can include CVD sources, heaters, etch tools or other processing tools.

[0079] A carrier rail has an area exposed in a horizontal direction and showing a risk for collecting loose particles. A carrier cleaning head 500 is shown at the exit from the front end module 802. The carrier cleaning head 500 can be adjacent to an entrance into a load lock chamber, i.e. the first vacuum chamber 804. The carrier cleaning head can be provided under atmospheric conditions, i.e. outside the first vacuum chamber 804. A carrier, and particularly one or more carrier rails, rods, or bars are cleaned by the carrier cleaning head 500 before the carrier enters the vacuum chambers of the substrate processing system 800. The carriers can be cleaned in-situ, i.e. while being within the substrate processing system. According to some embodiments, the position of the carrier cleaning head can be adjusted relative to a transport assembly of the vacuum processing system. For example, the position can be adjusted vertically and horizontally, perpendicular to the transport direction T.

[0080] According to one embodiment, a substrate processing system is provided. The substrate processing system includes a first vacuum chamber having a first wall. A carrier cleaning head according to embodiments of the present disclosure is arranged adjacent to the first wall of the first vacuum chamber, and particularly outside of the vacuum chamber. For example, a carrier transport assembly can be provided, wherein the carrier transport assembly is configured to transport a carrier having a top rail and bottom rail along a transport direction. The cleaning head body is distant from the top rail in a vertical direction and distant from the bottom rail in the vertical direction, and wherein the cleaning head body is distant from the carrier in a horizontal direction different from the transport direction.

[0081] A substrate processing system may further include a pump 820 in fluid communication with the second conduit of the carrier cleaning head. Further, a gas source 822, for example, for CD A, can be provided in fluid communication with the first conduit of the carrier cleaning head. The gas source can be a gas tank or a gas line of a factory for substrate processing.

[0082] FIG. 8 shows a carrier transport assembly including a plurality of rollers 100 in the first vacuum chamber 804 and in the second vacuum chamber 806. Exemplarily, the rollers 100 in the first vacuum chamber include a roller casing with a trapping surface. A carrier transport assembly can include rollers according to embodiments of the present disclosure. FIG. 8 shows the roller casings 110 exemplarily in the first vacuum chamber 804. Rollers according to embodiments of the present disclosure can be provided in each of the vacuum chambers of the substrate processing system.

[0083] FIG. 8 shows a substrate processing system 800 including a carrier cleaning head according to embodiments of the present disclosure and a carrier transport assembly with rollers according to the present disclosure. According to some embodiments, which can be combined with other embodiments described herein, particle trapping with a carrier cleaning head and particle trapping with a trapping surface of a roller casing can be provided separately from each other or in combination with each other.

[0084] According to one embodiment, a substrate processing system including a carrier transport assembly is provided. The carrier transport assembly includes a plurality of rollers arranged along a transport direction. Each of the plurality of rollers can be a roller according to embodiments of the present disclosure. The substrate processing system can include a vacuum chamber, wherein the plurality of rollers is provided within the vacuum chamber. Yet further, the substrate processing system can include one or more substrate processing stations 850. [0085] According to some implementations, in a physical vapor deposition (PVD) tool, such as AKT Pivot and NewAristo from Applied Materials Inc., substrate carriers move on a carrier transport assembly, wherein a rod or a rail of a carrier is moved on a roller arrangement. During system operation, particles can be generated due to the friction between the roller arrangement and the carrier. The particles may accumulate on the rod of the substrate carrier or may cause the substrate processing in a vacuum chamber to deteriorate. The particles accumulated on a carrier are transported through the system and may circulate in the system. Eventually, the particles can reach a flat panel substrate either because of airflow patterns, e.g. during venting and pumping of a vacuum chamber such as a load lock chamber, or because of electrostatic and/or dynamic effects.

[0086] FIG. 9 shows a method of maintaining a substrate processing system. At operation 902, maintenance is started. At operation 912 a plurality of brushes of two or more pairs of brushes or a plurality of brush pads, respectively, are removed from a cleaning head body of a carrier cleaning head. The plurality of brushes can be cleaned or the brushes can be replaced by new, for example, clean brushes. At operation 914, the carrier cleaning head is assembled by providing cleaned brushes to the carrier cleaning head. At an additional or alternative maintenance process, as shown at operation 922, a plurality of roller casings can be removed from a plurality of rollers of a carrier transport assembly. A trapping surface of the roller casings can be cleaned or removed for each of the plurality of roller casings. At operation 924, the plurality of rollers is assembled by providing a roller casing for each of the rollers. For example, a clean roller casing can be provided, either a new roller casing or a roller casing that has previously been cleaned.

[0087] FIG. 9 shows the pressure replacement and the roller casing replacement as separate maintenance processes. The two maintenance processes can be provided separately from each other or both maintenance processes can be provided.

[0088] FIG. 10 shows the method of manufacturing a device in a substrate processing system. For example, a device can be a display. The display may be manufactured on large area substrates of generation GEN 4.5 or higher, particularly in a PVD substrate processing system. At operation 950, a carrier supporting a substrate is transported into a substrate processing system having a load lock chamber. Particles adhering to the carrier can be trapped with a carrier cleaning head according to embodiments of the present disclosure. This is illustrated by operation 952. The substrate processing system includes a carrier transport assembly with a plurality of rollers. The transporting includes a rotation of a roller body for each of the rollers. At operation 954, particles generated at the roller are trapped in a roller casing having a trapping surface. At operation 956, one or more thin film layers of the device can be processed or deposited in the substrate processing system. FIG. 10 shows the trapping of particles adhering to the carrier and the trapping of particles generated during carrier transportation. Both trapping mechanisms can be provided separately from each other or in combination according to embodiments of the present disclosure.

[0089] According to embodiments, an in-situ removal of particles enables to reduce pre- and post-deposition particles that may adhere to the production sheets or substrates as well as consecutive particle-induced defect formation and yield loss.

[0090] Embodiments of the present disclosure provide one or more of the following advantages. Particles that are generated in a substrate processing system or potentially transferred into a vacuum processing system are trapped. Accordingly, the number of particles that may negatively impact substrate processing are reduced. Further, particle trapping is provided at predetermined locations such that product maintenance can be simplified, since the particles can be removed from the predetermined location during product maintenance. A cleaning efficiency is improved by providing an improved ratio of a purge gas flow and nozzle distance of the purge gas openings to the cleaning position. Purge gas flow can be reduced, which further impacts the ratio between the amount of purge gas and the suction capacity to improve cleaning efficiency. Trapping surfaces provided at a roller casing, i.e. adjacent to particle generation, can reduce distribution of particles in the substrate processing system.

[0091] 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.