Roller device for guiding flexible substrate, use of roller device for transporting flexible substrate, vacuum processing apparatus, and method of processing flexible substrate

Abstract

To provide a roller device for guiding a flexible substrate, use of a roller device for transporting a flexible substrate, a vacuum processing apparatus for processing a flexible substrate, and a method of processing a flexible substrate in a vacuum processing apparatus.SOLUTION: A roller device (100) includes a support surface (110) for contacting a flexible substrate (10). The support surface (110) has a coating (120) containing an electronegative polymer. The coating and the flexible substrate are configured to provide a charge affinity difference ΔCA of 50 nC / J≤ΔCA≤200 nC / J.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present disclosure relate to rollers for guiding flexible substrates. Further, embodiments of the present disclosure relate to apparatuses and methods for flexible substrate processing, specifically, flexible substrate coating in thin layers using roll-to-roll processing. Specifically, embodiments of the present disclosure relate to rollers utilized in the conveyance of flexible substrates in apparatuses and methods for coating flexible substrates in a stack of layers, for example, for thin film solar cell production, thin film battery production, and flexible display production.

Background Art

[0002] The processing of flexible substrates such as plastic films or plastic foils is in high demand in the packaging industry, semiconductor industry, and other industries. In particular, roll-to-roll (R2R) processing of flexible substrates has received high attention due to its low cost and high throughput. In particular, in the manufacturing of thin film batteries, display industry, and photovoltaic (PV) industry, roll-to-roll deposition systems have received high attention. For example, with the increasing demand for flexible touch panel elements, flexible displays, and flexible PV modules, the demand for depositing appropriate layers with an R2R coater has increased as a result.

[0003] Processing may involve coating, etching, and other processing operations performed on the substrate for corresponding applications, with materials such as metals, semiconductors, and dielectric materials. For example, coating processes (such as CVD processes or PVD processes, particularly sputtering processes) may be utilized to deposit thin layers on flexible substrates. Systems for performing such operations generally include a coating drum (such as a cylindrical roller) connected to a processing system equipped with a roller assembly for conveying flexible substrates.

[0004] In order to achieve high-quality coating on a flexible substrate, various issues related to the conveyance of the flexible substrate must be overcome. For example, it is still difficult to achieve appropriate substrate tension and good contact between the substrate and the roller while processing a flexible substrate moving under vacuum conditions.

[0005] Accordingly, there is a continuing need to improve the conveyance of flexible substrates in roll-to-roll processing systems, particularly for coating flexible substrates with high-quality layers or layer stacks having improved uniformity, improved product lifetime, and fewer defects per surface area. SUMMARY OF THE INVENTION

[0006] In light of the above, there is provided a roller device for guiding a flexible substrate, the use of a roller device for conveying a flexible substrate, a vacuum processing apparatus for processing a flexible substrate, and a method for processing a flexible substrate within a vacuum processing apparatus according to the independent claims. Further aspects, advantages, and features will be apparent from the dependent claims, the description herein, and the accompanying drawings.

[0007] According to one aspect of the present disclosure, there is provided a roller device for guiding a flexible substrate. The roller device includes a support surface for contacting the flexible substrate. The support surface has a coating including an electro-negative polymer.

[0008] According to a further aspect of the present disclosure, there is provided the use of a roller device for conveying a flexible substrate within a vacuum processing apparatus. The roller device includes a support surface for contacting the flexible substrate. The support surface has a coating including an electro-negative polymer.

[0009] According to another aspect of the present disclosure, a vacuum processing apparatus for processing a flexible substrate is provided. The vacuum processing apparatus includes a first spool chamber that houses a storage spool for supplying the flexible substrate. Further, the vacuum processing apparatus includes a processing chamber disposed downstream from the first spool chamber. The processing chamber includes a plurality of processing units including at least one deposition unit. Further, the processing chamber includes a roller device for guiding the flexible substrate to pass through the plurality of processing units. The roller device includes a support surface for contacting the flexible substrate. The support surface has a coating including an electro-negative polymer. Further, the vacuum processing apparatus includes a second spool chamber disposed downstream from the processing chamber. The second spool chamber houses a take-up spool for winding up the flexible substrate after processing.

[0010] According to a further aspect of the present disclosure, a method for processing a flexible substrate in a vacuum processing apparatus is provided. The method includes feeding out the flexible substrate from a storage spool provided in a first spool chamber. Further, the method includes processing the flexible substrate while guiding the flexible substrate by a roller device provided in a processing chamber. The roller device includes a support surface for contacting the flexible substrate. The support surface has a coating including an electro-negative polymer. Further, the method includes winding up the flexible substrate onto a take-up spool provided in a second spool chamber after processing.

[0011] Embodiments are also directed to an apparatus for implementing the disclosed methods and include components of the apparatus for performing the aspects of the methods described respectively. These aspects of the methods can be implemented using hardware components, a computer programmed by appropriate software, any combination of these two, or any other means. Further, embodiments according to the present disclosure are also directed to a method for operating the described apparatus. The method for operating the described apparatus includes aspects of the methods for implementing any function of the apparatus.

Brief Description of the Drawings

[0012] To enable a more detailed understanding of the above features of the present disclosure, a more specific description of the present disclosure, briefly outlined above, can be obtained by referring to the various embodiments. The accompanying drawings relate to embodiments of the present disclosure and are described in the following description.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A-6B

Modes for Carrying Out the Invention

[0013] Various embodiments of the present disclosure are referred to in more detail hereinafter. One or more examples of these embodiments are shown in the drawings. In the following description of the drawings, the same reference numerals represent the same components. For each individual embodiment, only the differences will be described. Each example is provided as an illustration of the present disclosure, but the examples are not intended to limit the present disclosure. Furthermore, features illustrated and described as part of one embodiment may be used in or with other embodiments, thereby resulting in still other embodiments. This description is intended to include such modifications and variations.

[0014] Referring to FIG. 1, a roller device 100 for guiding a flexible substrate 10 according to the present disclosure is shown. According to an embodiment that can be combined with any other embodiment described herein, the roller device 100 includes a support surface 110 for contacting the flexible substrate 10. The support surface 110 has a coating 120 including an electronegative polymer.

[0015] By providing a roller device with a coating including an electronegative polymer, an improvement in the contact between the flexible substrate and the roller device is beneficially achieved during the conveyance of the flexible substrate. Thus, the embodiments of the roller devices described herein are improved as compared to conventional rollers used for guiding flexible substrates, particularly in roll-to-roll vacuum processing apparatuses. More specifically, in the roller devices described herein, a substantially constant and homogeneous contact force can be achieved between the flexible substrate and the roller device, and as a result, the clamping or adhesion of the flexible substrate to the roller device can be improved. The contact force may also be referred to as a clamping force. Further, by utilizing the roller devices having the coatings described herein, the heat transfer from the flexible substrate to the roller device can be improved as compared to the prior art. This can be advantageous for processing heat-sensitive flexible substrates, particularly thin polymer flexible substrates having a substrate width W of 0.3 m ≤ W ≤ 8 m. This improved heat transfer results from the fact that during guiding of the flexible substrate by the roller device of the present disclosure, direct contact between the substrate and the coated support surface can be realized at a substantially complete contact surface, i.e., the fact that the region having a gap (up to the microscale) between the flexible substrate and the coated support surface can be reduced or substantially eliminated.

[0016] Furthermore, in state-of-the-art technologies, substrate tension is typically increased to improve the contact between the substrate and the substrate transfer roller. However, it should be noted that this can cause several problems when thin flexible substrates (e.g., flexible substrates having a substrate thickness ST of 20 μm ≤ ST ≤ 1 mm) are used. Therefore, it should be noted that in order to compensate for the reduction in the effective substrate rigidity of thinner substrates, it is necessary to improve the effective contact force or clamping force between the flexible substrate and the roller as the substrate width increases.

[0017] Therefore, the embodiments of the roller device described herein are beneficially well-suited for guiding polymer flexible substrates where the substrate width W is 0.3 m ≤ W ≤ 8 m and the substrate thickness ST is 20 μm ≤ ST ≤ 1 mm.

[0018] Furthermore, other conventional means for improving the contact between the flexible substrate and the transfer roller or guiding roller (e.g., application of electrostatic charges to the substrate and / or the transfer roller / guiding roller) can be reduced or even eliminated. In this regard, it should be noted that applying electrostatic charges to the substrate (e.g., by using a scalable linear electron beam source) and / or to the transfer roller / guiding roller (e.g., by applying a DC voltage to the transfer roller / guiding roller) can cause damage to the flexible substrate and / or the roller surface, for example, due to arc discharges during operation. Therefore, beneficially, the roller device of the present disclosure can substantially reduce or even eliminate problems associated with conventional means for improving the contact between the flexible substrate and the transfer roller.

[0019] Before explaining various further embodiments of the present disclosure in more detail, some aspects related to several terms used herein will be explained.

[0020] In the present disclosure, a "roller device" can be understood as a drum or a roller having a substrate support surface for contacting a flexible substrate. Specifically, the roller device can be rotatable about a rotation axis and can include a substrate guiding region. Typically, the substrate guiding region is a curved substrate support surface (e.g., a cylindrically symmetric surface) of the roller device. The curved substrate support surface of the roller device can be adapted to (at least partially) contact the flexible substrate while guiding the flexible substrate. The substrate guiding region can be defined as the angular range of the roller device where the substrate contacts the curved substrate surface while the substrate is being guided, and can correspond to the enlacement angle of the roller device. In some embodiments, the enlacement angle of the roller device can be 120° or more, specifically 180° or more, or even 270° or more.

[0021] In the present disclosure, a "flexible substrate" can be understood as a substrate that can be bent. For example, a "flexible substrate" can be a "foil" or a "web". In the present disclosure, the terms "flexible substrate" and "substrate" can be used synonymously. For example, the flexible substrates described herein can include materials such as PET, HC-PET, PE, PI, PU, TaC, OPP, BOOP, CPP, one or more metals, paper, combinations thereof, and coated substrates such as hard-coated PET (e.g., HC-PET, HC-TaC). In some embodiments, the flexible substrate is a COP substrate provided with index-matched (IM) layers on both sides thereof. For example, the thickness of the substrate can be 1 μm or more and 200 μm or less. More specifically, the thickness of the substrate can be selected from a range having a lower limit of 8 μm and an upper limit of 25 μm, for example, for food packaging applications.

[0022] In the present disclosure, the expression "support surface for contacting a flexible substrate" can be understood as the outer surface of a roller device configured to contact the flexible substrate during the induction or conveyance of the flexible substrate. Usually, the support surface is the curved outer surface of the roller device, particularly a cylindrical outer surface.

[0023] In the present disclosure, the expression "support surface having a coating" can be understood as the support surface of the roller device including a coating, that is, the support surface is coated. Specifically, the coating includes an electro-negative polymer. An "electro-negative polymer" can be understood as a polymer having electro-negative properties. Usually, the coating is provided on the entire support surface. Specifically, the coating has a certain thickness (for example, a thickness T selected from the range of 2.5 μm ≤ T ≤ 15 μm).

[0024] According to some embodiments that can be combined with other embodiments described herein, the coating 120 has triboelectric properties. In other words, the electro-negative polymer can be configured to generate static charges by frictional contact with the flexible substrate. Specifically, the electro-negative polymer (for example, a fluoropolymer) can be configured to generate mirror charges on the flexible substrate surface during induction by the triboelectric effect. The triboelectric effect (also called triboelectrification) is a type of contact electrification in which a material becomes charged after frictional contact with another material. In other words, the triboelectric effect can be explained as the movement of charges (electrons) from one material to another material after frictional contact or sliding contact. The total charge transfer between two materials is defined by the difference in charge affinity between the surfaces of the two contacting materials.

[0025] For example, the substrate material described in this specification has a charge affinity (CA) of -90 nC / J ≤ CA ≤ -40 nC / J. For example, PET has a charge affinity CA of CA ≈ -40 nC / J, BOOP has a charge affinity CA of CA ≈ -85 nC / J, and LDEP, HDPE, and PP have a charge affinity CA of CA ≈ -90 nC / J. Coatings containing the electro-negative polymers described in this specification, specifically coatings containing or consisting of fluoropolymers, specifically coatings containing or consisting of PTFE and / or PFA, have a charge affinity CA of CA ≈ -190 nC / J.

[0026] Therefore, advantageously, the coating provided on the support surface of the roller device described in this specification ensures that the coated roller device is negatively charged compared to the substrate even in the absence of an externally applied electric field. Therefore, according to an embodiment that can be combined with other embodiments of this specification, it should be understood that the coating of the support surface of the roller device can be configured to provide a charge affinity difference ΔCA with respect to the flexible substrate induced by the roller device. Specifically, the charge affinity difference ΔCA between the coating and the substrate can be 50 nC / J ≤ ΔCA ≤ 200 nC / J, specifically 100 nC / J ≤ ΔCA ≤ 150 nC / J.

[0027] As outlined above, in the embodiment of the roller device described in this specification, the coating of the electro-negative polymer provided on the support surface of the roller device can be configured to cause triboelectrification with the flexible substrate during the induction of the flexible substrate. Usually, the flexible substrate is induced by rotating the roller device 100 about the rotation axis 111 of the roller device, as exemplarily shown by the arrow in FIG. 1. For example, the roller device can be actively driven. In other words, drive can be applied to rotate the roller device.

[0028] Therefore, by providing a coating containing an electronegative polymer on the support surface of the roller device configured to generate mirror charges on the surface of the flexible substrate in contact with the roller device during induction of the substrate, improvement in adhesion of the flexible substrate to the roller device is beneficially achieved. In other words, by providing a coating having triboelectric properties on the support surface of the roller device, charge transfer between the coating and the flexible substrate is beneficially achieved, and as a result, a constant and homogeneous contact force (also called a pinning force or a clamping force) between the flexible substrate and the roller device can be ensured. Further, by utilizing the triboelectric effect, slippage between the flexible substrate and the coating provided on the support surface of the roller device is beneficially reduced.

[0029] According to some embodiments that can be combined with other embodiments described herein, the electronegative polymer can be dielectric. Specifically, the electronegative polymer can be an electrically insulating material, which can be polarized. For example, the electronegative polymer can be an elastomeric fluoropolymer including a fluoropolymer, specifically, for example, perfluoroalkoxy polymer (PFA) and / or polytetrafluoroethylene (PTFE). In particular, the fluoropolymer can consist of PFA or PTFE. A coating containing or consisting of a fluoropolymer (e.g., PFA or PTFE) beneficially provides a coating having a very high dielectric breakdown strength. Further, a coating containing or consisting of a fluoropolymer (e.g., PFA or PTFE) beneficially provides a low coefficient of friction, specifically, an ultra-low coefficient of friction. Therefore, beneficially, a low wear rate of the coating comparable to, for example, steel is achieved, guaranteeing the life of the coating. In other words, a fluoropolymer coating providing a fluorinated polymer coating surface beneficially provides an excellent low friction performance level for reducing effective coating wear.

[0030] According to some embodiments, which may be combined with other embodiments described herein, the coating 120 may have a coefficient of friction μ of μ≦0.1, particularly μ≦0.05. More specifically, the non-lubricated fluoropolymer coefficient of friction μ may be μ≦0.1, particularly μ≦0.05. It is noted that local wear from the coating asperities can result in highly hydrophobic hydrodynamic boundary lubrication, beneficially further reducing the coefficient of friction by a factor F of about F=10. Thus, beneficially, an effective coating material wear rate close to the intrinsic wear rate level of steel can be achieved.

[0031] For example, according to some embodiments, which may be combined with other embodiments described herein, the coating 120 has a surface roughness of 0.4×10 -7 MPa -1 ≦k a ≦2.0×10 -6 Wear rate constant k in MPa-1 a In other words, the coating may have a -7 MPa -1 ≦k a ≦2.0×10 -6 MPa -1 The wear rate constant k is selected from the range a The wear rate constant k a is the dimensionless wear rate constant k divided by the hardness [MPa], i.e., k a [MPa -1 ]=k / hardness [MPa].

[0032] According to some embodiments, which may be combined with other embodiments described herein, the coating 120 may have a thickness T in the range of 2.5 μm≦T≦15 μm. Providing a coating with a thickness T selected from the range of 2.5 μm≦T≦15 μm may be beneficial to ensure sufficient capacitance to ensure sufficient pinning force between the flexible substrate and the coated support surface of the roller device.

[0033] According to some embodiments that can be combined with other embodiments described herein, the coating 120 has a breakdown field strength BFS of 2.0 MV / cm ≤ BFS ≤ 30 MV / cm. For example, a PFA coating with a thickness T of T = 5 μm has a BFS of 2.0 MV / cm when an electric field of 300 V is applied. A PTFE coating with a thickness T of T = 10 μm has a BFS of 24 MV / cm when an electric field of 300 V is applied.

[0034] Referring illustratively to FIG. 2, according to some embodiments that can be combined with other embodiments described herein, the roller device 100 is cylindrical and has a length L of 0.5 m ≤ L ≤ 8.5 m. Further, the roller device 100 can have a diameter D of 1.0 m ≤ D ≤ 3.0 m. Thus, beneficially, the roller device is configured to guide and convey a flexible substrate having a large width.

[0035] According to some embodiments that can be combined with other embodiments described herein, the roller device can have one or more E - chuck devices (not explicitly shown). The E - chuck device can be understood to be a device configured to supply an electrostatic charge for holding the substrate by electrostatic force. Specifically, one or more E - chuck devices can apply an attractive force for holding the flexible substrate and / or bringing the web into contact with the curved surface of the roller device. Thus, a constant and homogeneous contact force between the flexible substrate and the roller device can be further improved.

[0036] In view of the above, according to a further aspect of the present disclosure, it should be understood that there is provided the use of a roller device according to any of the embodiments described herein for conveying a flexible substrate within a vacuum processing apparatus, specifically, within a vacuum processing apparatus according to the embodiments described with reference to FIGS. 3 and 4.

[0037] Referring to FIG. 3 by way of example, a vacuum processing apparatus 200 according to the present disclosure is described. According to an embodiment that can be combined with any other embodiment described herein, the vacuum processing apparatus 200 includes a first spool chamber 210 that houses a storage spool 212 for supplying the flexible substrate 10. Further, the vacuum processing apparatus 200 includes a processing chamber 220 disposed downstream from the first spool chamber 210. The processing chamber 220 includes a plurality of processing units 221. The plurality of processing units 221 includes at least one deposition unit. For example, the plurality of processing units may be circumferentially arranged around the roller device 100 as schematically shown in FIGS. 3 and 4. When the roller device 100 rotates, the flexible substrate is guided to pass through the processing unit facing the curved substrate support surface of the roller device, so that the surface of the flexible substrate can be processed while passing through the processing unit at a predetermined speed. For example, the plurality of processing units may include one or more units selected from the group consisting of a deposition unit, an etching unit, and a heating unit. The deposition unit of the vacuum processing apparatus described herein may be a sputter deposition unit (e.g., an AC (alternating current) sputter source or a DC (direct current) sputter source, a CVD deposition unit, a PECVD deposition unit, or a PVD deposition unit).

[0038] Further, the processing chamber 220 includes a roller device 100 for guiding the flexible substrate to pass through the plurality of processing units 221. The roller device 100 includes a support surface 110 for contacting the flexible substrate 10. The support surface 110 has a coating 120 including an electro-negative polymer. Specifically, the roller device is a roller device according to any embodiment described herein. Further, the vacuum processing apparatus 200 includes a second spool chamber 250 disposed downstream from the processing chamber 220. The second spool chamber 250 houses a take-up spool 252 for taking up the flexible substrate 10 after processing.

[0039] Therefore, the embodiments of the vacuum processing apparatus described in this specification are improved compared to conventional vacuum processing apparatuses. Specifically, by providing a vacuum processing apparatus equipped with a roller device as described in this specification, beneficially, improved induction and conveyance of flexible substrates are realized. More specifically, the roller device described in this specification provides a substantially constant and homogeneous contact force between the flexible substrate and the roller device, and can improve the clamping or adhesion of the flexible substrate to the roller device, so that the induction and conveyance of the flexible substrate can be improved. Therefore, beneficially, the conveyance of a flexible substrate that is substantially wrinkle-free can be reliably performed, and as a result, a higher-quality processing result (for example, a higher-quality coating on the flexible substrate) can be obtained.

[0040] In the present disclosure, the "vacuum processing apparatus" can be understood as an apparatus configured to process a substrate, particularly a flexible substrate described in this specification. Specifically, the vacuum processing apparatus can be a roll-to-roll (R2R) processing apparatus configured to coat a flexible substrate with a stack of layers. Usually, the vacuum processing apparatus has at least one vacuum chamber, specifically, a vacuum processing chamber. Further, the processing apparatus can be configured such that the substrate length is 500 m or more, 1000 m or more, or several km. The width of the substrate can be 300 mm or more, specifically, 500 mm or more, more specifically, 1 m or more. Further, the substrate width can be 8 m or less, particularly 6 m or less.

[0041] In the present disclosure, the "processing chamber" can be understood as a chamber having at least one deposition unit for depositing a material on a substrate. Therefore, the processing chamber may also be referred to as a deposition chamber. The term "vacuum" as used in this specification can be understood to mean a technical vacuum having a vacuum pressure of less than 10 mbar, for example. Typically, the pressure in the vacuum chamber described in this specification is between 10 -5 mbar and about 10 -8 mbar, more typically between 10 -5 mbar and 10-7 between mbar, and more typically still, about 10 -6 mbar to about 10 -7 mbar.

[0042] As used herein, the terms "upstream from" and "downstream from" may indicate the relative position of each chamber or component along the substrate transport path with respect to another chamber or component. For example, during operation, a substrate is directed from a first spool chamber 210 through a processing chamber 220 and then, via a roller assembly, to a second spool chamber 250 along the substrate transport path. Thus, the processing chamber 220 is downstream of the first spool chamber 210, and the first spool chamber 210 is upstream of the processing chamber 220. During operation, a substrate is first directed or transported to pass through a first roller or a first component and then is directed or transported to pass through a second roller or a second component. The second roller or the second component is downstream of the first roller or the first component.

[0043] As illustrated in FIGS. 3 and 4, the first spool chamber 210 is typically configured to house a storage spool 212, and the storage spool 212 can be provided with the flexible substrate 10 wound thereon. During operation, the flexible substrate 10 can be fed out from the storage spool 212 and conveyed from the first spool chamber 210 towards the processing chamber 220 along a substrate conveyance path (illustrated by the arrows in FIGS. 3 and 4). The term "storage spool" as used herein can be understood to be a roll that houses the flexible substrate to be coated. Thus, the term "wind-up spool" as used herein can be understood to be a roll adapted to receive the coated flexible substrate. Further, the term "storage spool" may also be referred to as a "supply roll", and the term "wind-up spool" may also be referred to as a "take-up roll".

[0044] In the present disclosure, a "processing unit" can be understood to be a unit or device configured to process the flexible substrate described herein. For example, the processing unit may be a deposition unit. Specifically, the deposition unit may be a sputter deposition unit (e.g., an AC sputter source or a DC sputter source). However, the processing apparatus described herein is not limited to sputter deposition, and other deposition units may also be used additionally or alternatively. For example, in some implementations, a CVD deposition unit, an evaporation deposition unit, a PECVD deposition unit, or other deposition units may be utilized. Thus, it should be understood that a deposition unit (e.g., a plasma deposition source) can deposit a thin film on a flexible substrate and can be adapted to form, for example, a flexible display device, a touch screen device component, or other electronic or optical devices.

[0045] According to some embodiments that can be combined with other embodiments described herein, the roller device 100 of the vacuum processing apparatus is a processing drum. In the present disclosure, the "processing drum" can be understood as a drum or roller having a substrate support surface for contacting the flexible substrate during processing. Specifically, the processing drum can be rotatable about a rotation axis 111 and can include a substrate guiding region. Typically, the substrate guiding region is a curved substrate support surface (e.g., a cylindrically symmetric surface) of the processing drum. The curved substrate support surface of the processing drum can be adapted to (at least partially) contact the flexible substrate during the operation of the processing apparatus described herein.

[0046] Specifically, with exemplary reference to FIG. 4, the roller device 100 can be connected to a device 240 for applying a potential to the processing drum. The processing drum is the roller device 100 according to any of the embodiments described herein.

[0047] In the present disclosure, the "device for applying a potential to the processing drum" can be understood as a device configured to apply a potential to the processing drum, specifically, to the substrate support surface of the processing drum. In particular, the device for applying a potential can be configured to supply a medium frequency (MF) potential. For example, the intermediate frequency (MF) potential can be from 1 kHz to 100 kHz. In the present disclosure, the "device for applying a potential" can also be referred to as a "potential application device". Applying an MF potential to the processing drum has the advantage that it can substantially avoid or even eliminate the charge-up of the substrate, particularly the layer deposited on the substrate. Therefore, a layer of higher quality (e.g., higher uniformity, fewer defects, etc.) can be deposited on the substrate. Therefore, providing a potential application device is beneficial for further improving a constant and homogeneous contact force between the flexible substrate and the roller device, and as a result, improved substantially wrinkle-free flexible substrate conveyance can be achieved during substrate processing.

[0048] Referring to FIGS. 3 and 4 by way of example, it should be understood that typically, the vacuum processing apparatus 200 is configured to be able to guide the flexible substrate 10 from the first spool chamber 210 to the second spool chamber 250 along a substrate conveyance path. The substrate conveyance path can pass through the processing chamber 220. For example, the flexible substrate can be coated with a stack of layers in a deposition chamber. Further, as illustrated in FIGS. 3 and 4, a roller assembly including a plurality of rolls or rollers can be provided to convey the substrate along the substrate conveyance path. FIGS. 3 and 4 show a roller assembly including four rollers. According to different configurations, it should be understood that the roller assembly can include five or more rollers, particularly ten or more rollers, disposed between the storage spool and the take-up spool.

[0049] Referring to FIGS. 3 and 4 by way of example, according to some embodiments of the present specification that can be combined with any other embodiments described herein, the roller assembly can be configured to convey the flexible substrate along a substrate conveyance path that is partially convex and partially concave from the first spool chamber to the second spool chamber. In other words, the substrate conveyance path can be curved partially to the right and partially to the left, whereby some guide rollers contact the first major surface of the flexible substrate and some guide rollers contact the second major surface on the opposite side of the first major surface of the flexible substrate.

[0050] For example, the first guide roller 207 in FIG. 4 contacts the second major surface of the flexible substrate, and the flexible substrate is bent to the left while being guided by the first guide roller 207 (the "convex" portion of the substrate conveyance path). The second guide roller 208 in FIG. 4 contacts the first major surface of the flexible substrate, and the flexible substrate is bent to the right while being guided by the second guide roller 208 (the "concave" portion of the substrate conveyance path).

[0051] In some embodiments, one or more rollers of the roller assembly (e.g., guide rollers) can be disposed between the storage spool 212 and the processing drum (i.e., the roller device 100) and / or downstream of the processing drum. For example, in the embodiment shown in FIG. 3, two guide rollers are provided between the storage spool 212 and the processing drum, and at least one guide roller may be disposed within the first spool chamber, and at least one guide roller may be disposed within the processing chamber upstream of the processing drum. In some embodiments, three, four, five or more, particularly eight or more guide rollers are provided between the storage spool and the processing drum. The guide rollers may be active or passive rollers.

[0052] As used herein, an “active” roller or roll can be understood to be a roller provided with a drive unit or motor for actively moving or rotating each roller. For example, the active roller can be adjusted to produce a predetermined torque or a predetermined rotational speed. Typically, the storage spool 212 and the take-up spool 252 can be provided as active rollers. Further, the active roller can be configured as a substrate tension roller configured to adjust the tension of the substrate with a predetermined tension during operation. A “passive” roller can be understood to be a roller or roll not provided with a drive unit for actively moving or rotating the passive roller. The passive roller can rotate by the frictional force of the flexible substrate that can come into direct contact with the outer roller surface during operation.

[0053] As illustrated in FIG. 4, one or more guiding rollers 213 may be disposed downstream from the processing drum (i.e., the roller device 100) and upstream from the second spool chamber 250. For example, in order to smoothly guide the flexible substrate 10 to the take-up spool 252, at least one guiding roller may be disposed within the processing chamber 220 downstream from the processing drum for guiding the flexible substrate 10 toward the second spool chamber 250 disposed downstream from the processing chamber 220, or at least one guiding roller may be disposed within the second spool chamber 250 upstream from the processing drum for guiding the flexible substrate in a substantially tangential direction with respect to the substrate support surface of the processing drum.

[0054] According to some embodiments that can be combined with other embodiments described herein, one or more guiding rollers of the roller assembly may include a coating including an electro-negative polymer, as exemplified for the roller device according to any of the embodiments described herein.

[0055] According to some embodiments, some or all of the chambers of the vacuum processing apparatus 200 may be configured as evacuable vacuum chambers. For example, the vacuum processing apparatus may include components and devices that enable the generation or maintenance of a vacuum within the first spool chamber 210 and / or the processing chamber 220 and / or the second spool chamber 250. Specifically, the vacuum processing apparatus may include a vacuum pump, an exhaust duct, a vacuum seal, etc. for generating or maintaining a vacuum within the first spool chamber 210 and / or the processing chamber 220 and / or the second spool chamber 250.

[0056] Referring to FIG. 4 by way of example, according to an embodiment that can be combined with other embodiments described herein, the sealing device 205 can be provided between adjacent chambers, for example, between the first spool chamber 210 and the processing chamber 220, and / or between the processing chamber 220 and the second spool chamber 250. Thus, advantageously, the take-up chambers (i.e., the first spool chamber 210 and the second spool chamber 250) can be evacuated or evacuated independently, particularly independently of the processing chamber. The sealing device 205 can include an expandable seal configured to press the substrate against a flat sealing surface.

[0057] As illustrated in FIG. 4, typically, the processing drum (i.e., the roller device described herein) is configured to guide the flexible substrate 10 through a plurality of deposition units (e.g., through the first deposition unit 221A, the second deposition unit 221B, and the third deposition unit 221C). As shown in FIG. 4, the individual deposition units may be provided in separate compartments. By being provided in separate compartments, a modular combination of several different subsequent deposition processes (e.g., CVD, PECVD, and / or PVD) is possible, and very good gas separation between the various subsequent deposition processes is ensured. Thus, depending on the selected sequence of deposition units, various different laminated layers can be deposited on the flexible substrate.

[0058] FIG. 5A shows a schematic side view of a processing apparatus according to an alternative configuration, and FIG. 5B shows a schematic bottom view of the processing apparatus shown in FIG. 5A. In particular, with reference to FIGS. 5A and 5B by way of example, the plurality of processing units may include a set 230 of evaporation crucibles aligned along a line 222 extending parallel to the axis of rotation 111 of the roller device 100, or may be configured as a set 230 of evaporation crucibles. Thus, the vacuum processing apparatus can be an evaporation apparatus for depositing a vapor deposition material on the substrate 10. For example, the set 230 of evaporation crucibles shown in FIG. 5A includes crucibles 211 to 217. As illustrated in FIG. 5B, the evaporation crucibles are typically configured to generate a cloud 255 of evaporation material deposited on the flexible substrate 10. As shown in FIG. 5B, the plurality of processing units can be arranged in a direction across the substrate width W.

[0059] The "evaporation crucible" can be understood to be a reservoir for the material that evaporates by heating the evaporation crucible. More specifically, the evaporation crucible can be provided with a material supply unit for supplying the material to be evaporated to the crucible. For example, the material to be evaporated may be supplied to the evaporation crucible in the form of a wire that can be melted by the evaporation crucible. According to some embodiments, the evaporation crucible can be configured as an evaporator boat, particularly when the material to be evaporated is supplied in the form of a wire. Thus, the set of evaporation crucibles described herein can be a set of evaporator boats. The material to be vapor deposited may be a metal (e.g., aluminum, copper, or any other metal). The processing apparatus exemplarily described with reference to FIGS. 5A and 5B is particularly well-suited for coating substrates used in the packaging industry, particularly the food packaging industry.

[0060] Referring illustratively to the flowchart shown in FIG. 6A, a method 300 for processing a flexible substrate 10 within a vacuum processing apparatus 200 according to the present disclosure is described. According to an embodiment that can be combined with any other embodiment described herein, the method includes feeding the flexible substrate 10 from a storage spool 212 provided within a first spool chamber 210 (shown by block 310 in FIG. 6A). Further, the method includes processing the flexible substrate 10 (shown by block 320 in FIG. 6A) while guiding the flexible substrate by a roller device 100 provided within a processing chamber 220. The roller device 100 includes a support surface 110 for contacting the flexible substrate 10. The support surface 110 has a coating 120 including an electro-negative polymer. Specifically, the roller device 100 can be a roller device according to any embodiment described herein. Further, the method includes winding the flexible substrate onto a take-up spool 252 provided within a second spool chamber 250 after processing (represented by block 330 in FIG. 6A).

[0061] Referring illustratively to FIG. 6B, according to some embodiments that can be combined with other embodiments described herein, the method further includes applying a potential to the roller device 100 (represented by block 340 in FIG. 6B). For example, applying a potential to the roller device (block 340) can include applying an intermediate frequency potential having a frequency from 1 kHz to 100 kHz. Specifically, applying a potential to the roller device 100 typically includes using a device 240 for applying a potential, as described with reference to FIG. 4 for example.

[0062] It should be understood that the method for processing a flexible substrate within a vacuum processing apparatus can be implemented, for example, by using a vacuum processing apparatus 200 according to any embodiment described herein with reference to FIGS. 3 and 4.

[0063] In view of the above, it should be understood that the embodiments described herein provide improved flexible substrate conveyance in a roll-to-roll processing apparatus so as to be able to process a thinner and wider flexible substrate and improve the processing result as compared with the prior art.

[0064] The above description is directed to embodiments, but other and further embodiments may be devised without departing from the basic scope of the disclosure, and the scope of the disclosure is defined by the appended claims.

Claims

1. A roller device (100) for guiding a flexible substrate (10), the roller device comprising a support surface (110) for contacting the flexible substrate (10), the support surface (110) having a coating (120) comprising an electronegative polymer.

2. The roller device (100) of claim 1 , wherein the coating (120) has triboelectric properties.

3. The roller device (100) of claim 1 or 2, wherein the electronegative polymer is dielectric.

4. 4. The roller device (100) of claim 1, wherein the coating (120) has a coefficient of friction μ of μ≦0.

1.

5. The coating (120) is 0.4×10 －７ MPa －１ ≦k ａ ≦2.0×10 －６ MPa －１ Friction constant k ａ The roller device (100) according to any one of claims 1 to 4, comprising:

6. 6. The roller device (100) of claim 1, wherein the coating (120) has a thickness T of 2.5 μm≦T≦15 μm.

7. 7. The roller device (100) of claim 1, wherein the coating (120) has a breakdown field strength BFS of 2.0 MV / cm < BFS < 30 MV / cm.

8. 8. The roller device (100) according to any one of claims 1 to 7, wherein the electronegative polymer is a fluoropolymer, in particular a perfluoroalkoxy polymer (PFA) or a polytetrafluoroethylene (PTFE).

9. 9. The roller device (100) of claim 1, wherein the roller device is cylindrical with a length L of 0.5 m≦L≦5.0 m.

10. 10. The roller device (100) of any one of claims 1 to 9, wherein the roller device has a diameter D, where 1.0 m≦D≦3.0 m.

11. 1. Use of a roller device (100) for transporting a flexible substrate (10) in a vacuum processing apparatus (200), the roller device comprising a support surface (110) for contacting the flexible substrate (10), the support surface (110) having a coating (120) comprising an electronegative polymer.

12. A vacuum processing apparatus (200) for processing a flexible substrate (10), comprising: a first spool chamber (210) for housing a storage spool (212) for supplying the flexible substrate (10); a processing chamber (220) disposed downstream from the first spool chamber (210), the processing chamber (220) comprising a plurality of processing units (221) comprising at least one deposition unit, and a roller device (100) for guiding the flexible substrate past the plurality of processing units (221), the roller device comprising a support surface (110) for contacting the flexible substrate (10), the support surface (110) having a coating (120) comprising an electronegative polymer; and a second spool chamber (250) disposed downstream from said processing chamber (220) for accommodating a take-up spool (252) for taking up said flexible substrate (10) after processing; A vacuum processing apparatus (200) comprising:

13. 13. The vacuum processing apparatus (200) of claim 12, wherein the roller device (100) is a processing drum, the processing drum being connected to a device (240) for applying an electrical potential to the processing drum.

14. A method (300) for processing a flexible substrate (10) in a vacuum processing apparatus (200), comprising: unloading the flexible substrate (10) from a storage spool (212) disposed within a first spool chamber (210); processing the flexible substrate (10) while guiding the flexible substrate by a roller device (100) disposed in a processing chamber (220), the roller device (100) comprising a support surface (110) for contacting the flexible substrate (10), the support surface (110) having a coating (120) comprising an electronegative polymer; After processing, winding the flexible substrate onto a take-up spool (252) located within a second spool chamber (250). The method includes:

15. The method of claim 14, further comprising applying (340) an electrical potential to the roller device (100).

Images