Flexible substrate transport roller, vacuum processing apparatus, and roller cooling method

Abstract

A roller (100) for transporting a flexible substrate is described. The roller (100) includes a first coolant supply (110) for cooling a first portion (101) of the roller (100) and a second coolant supply (120) for cooling a second portion (102) and a third portion (103) of the roller (100). The first portion (101) is disposed between the second portion (102) and the third portion (103). Additionally, a vacuum processing apparatus including the roller and a method for cooling the roller are described.

Description

[Technical field]

[0001]

[0001] Embodiments of the present disclosure relate to rollers for conveying flexible substrates. Furthermore, embodiments of the present disclosure relate to apparatuses and methods for processing flexible substrates using roll-to-roll processes, in particular for coating flexible substrates with thin layers. In particular, embodiments of the present disclosure relate to rollers used to convey flexible substrates in apparatuses and methods for coating flexible substrates with a stack of layers, for example for thin-film solar cell manufacturing, thin-film battery manufacturing, or flexible display manufacturing. [Background technology]

[0002]

[0002] The processing of flexible substrates, such as plastic films or foils, is in high demand in the packaging, semiconductor, and other industries. Processing may consist of coating the flexible substrate with materials, such as metals, semiconductors, dielectric materials, etching, and other processing operations performed on the substrate depending on the respective application. Systems that perform this task typically include a coating drum, e.g., a cylindrical roller, on which at least a portion of the substrate is coated, coupled to a processing system that includes a roller assembly for transporting the substrate.

[0003]

[0003] Thin layers can be deposited on flexible substrates using coating processes such as, for example, CVD, PVD, or evaporation processes. Roll-to-roll deposition machines are understood in which a significant length of flexible substrate, such as a kilometer or more, is unwound from a supply spool, coated with a stack of thin layers, and rewound on a take-up spool. Particularly in the manufacture of thin-film batteries, for example, lithium batteries, the display industry, and the photovoltaic (PV) industry, roll-to-roll deposition systems are of high interest. For example, the increasing demand for flexible touch panel elements, flexible displays, and flexible PV modules increases the demand for depositing suitable layers with a roll-to-roller.

[0004] In order to achieve high quality coatings on flexible substrates, various challenges related to the transportation of the flexible substrate must be overcome. For example, providing adequate substrate tension during processing of a moving flexible substrate under reduced pressure conditions, providing good substrate-to-roller contact and substrate cooling remain challenges. Furthermore, it has been found that heat extraction from flexible substrates using cooled substrate rollers still requires improvement, especially with regard to the uniformity of heat extraction.

[0005]

[0005] Thus, there is a continuing need for improved substrate transport rollers, improved roll-to-roll processing apparatus and methods. Summary of the Invention

[0006]

[0006] In view of the above, there is provided a roller for transporting a flexible substrate, a vacuum processing apparatus for processing a flexible substrate, and a method for cooling the roller according to the independent claims. Further aspects, advantages and features are apparent from the dependent claims, the description, and the accompanying drawings.

[0007] According to one aspect of the disclosure, there is provided a roller for transporting a flexible substrate, the roller including a first coolant supply for cooling a first portion of the roller, the roller further including a second coolant supply for cooling a second portion and a third portion of the roller, the first portion being disposed between the second portion and the third portion.

[0008] 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 processing chamber including a plurality of processing units having at least one deposition unit. Further, the vacuum processing apparatus includes a roller according to any embodiment described herein for guiding the flexible substrate through the plurality of processing units. In particular, the roller is connected to a coolant supply.

[0009] According to another aspect of the present disclosure, there is provided a method for cooling a roller for guiding a flexible substrate. The method includes cooling a first portion of the roller by supplying a first coolant to the first portion of the roller. Further, the method includes cooling a second portion and a third portion of the roller by supplying a second coolant to the second portion and the third portion of the roller. The first portion is provided between the second portion and the third portion. In particular, the first coolant has a first temperature and the second coolant has a second temperature different from the first temperature, in particular, the first temperature is lower than the second temperature.

[0010] According to another aspect of the present disclosure, there is provided a method of manufacturing a coated flexible substrate, the method including a roller according to any embodiment described herein, a vacuum processing apparatus according to any embodiment described herein, and a method of cooling the roller according to any embodiment described herein.

[0011]

[0011] The embodiments are also directed to apparatus for carrying out the disclosed methods, including apparatus parts for performing each of the described method aspects. These method aspects may be performed by hardware components, a computer programmed by appropriate software, by any combination of the two, or in any other manner. Additionally, embodiments according to the present disclosure also relate to methods for operating the described apparatus. Methods for operating the described apparatus include method aspects for performing any function of the apparatus.

[0012]

[0012] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the disclosure briefly outlined above can be had by reference to the embodiments. The accompanying drawings relate to embodiments of the present disclosure and are described below. [Brief description of the drawings]

[0013] [Figure 1A] 1 shows a schematic longitudinal cross-sectional view of a roller according to an embodiment described herein. [Diagram 2] 3 shows a schematic longitudinal cross-sectional view of a roller according to a further embodiment described herein; [Diagram 3] 1 shows a schematic diagram of a vacuum processing apparatus according to embodiments described herein. [Figure 4A-4B] 4A and 4B show block diagrams for explaining an embodiment of a method for cooling a roller that guides a flexible substrate according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0013] Reference will now be made in detail to various embodiments of the present disclosure. One or more examples of these embodiments are illustrated in the drawings. In the following description of the drawings, like reference numerals represent like components. Only the differences with respect to the individual embodiments are described. Each example is provided for the purposes of illustration of the disclosure and is not intended to limit the disclosure. Moreover, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to produce yet further embodiments. It is intended that the description include such modifications and variations.

[0015]

[0014] With reference to Fig. 1 by way of example, a roller 100 for conveying a flexible substrate according to the present disclosure is described. According to an embodiment, which may be combined with other embodiments described herein, the roller 100 includes a first coolant supply 110 for cooling a first portion 101 of the roller 100. Furthermore, the roller 100 includes a second coolant supply 120 for cooling a second portion 102 and a third portion 103 of the roller 100. The first portion (101) is provided between the second portion (102) and the third portion (103). In particular, the first portion 101 is an axially intermediate portion of the body 106 of the roller 100. Typically, the first portion 101 is a first cylindrical portion of the cylindrical body 106 of the roller 100. Thus, typically, the second portion 102 is a second cylindrical portion of the body 106 and the third portion 103 is a third cylindrical portion of the body 106.

[0016]

[0015] Thus, compared to the prior art, it is advantageous that an improved roller for transporting a flexible substrate is provided. In particular, the roller embodiments described herein provide for selective and separate cooling of different parts of the roller for transporting a flexible substrate. Thus, when a part of the roller is exposed to high temperatures, the central part of the roller, which is usually exposed to high temperatures during deposition of the material, can be cooled independently from the other parts of the roller. Furthermore, the roller embodiments described herein advantageously provide the possibility to extract heat from the flexible substrate in a uniform manner. Thus, the risk of wrinkling during transportation of the flexible substrate can be reduced or eliminated. As a result, the quality of the coating deposited on the flexible substrate can be improved. Furthermore, providing a roller with selectively coolable parts has the advantage that the shape of the roller can be controlled by using thermal material deformation effects such as thermal expansion and contraction. For example, the shape of the roller, and in particular the substrate support surface, can be modified. In particular, the shape of the roller can be controlled to have a flat substrate support surface, a concave substrate support surface, or a convex substrate support surface.

[0017] Before describing various further embodiments of the present disclosure in more detail, some aspects regarding some of the terminology used herein are explained.

[0018]

[0017] In the present disclosure, a "roller" may be understood as a drum or roller having a substrate support surface for contacting a flexible substrate. The expression "substrate support surface for contacting a flexible substrate" may be understood as an outer surface of the roller, for example an outer surface of a sleeve as described herein, configured to contact a flexible substrate during guiding or transporting the flexible substrate. Typically, the support surface is a curved outer surface of the roller, in particular a cylindrical outer surface. Thus, typically, the roller is rotatable about an axis of rotation and includes a substrate guiding region. Usually, the substrate guiding region is a curved substrate support surface of the roller, for example a cylindrically symmetric surface. The curved substrate support surface of the roller may be adapted to (at least partially) contact the flexible substrate during guiding of the flexible substrate. The substrate guiding region may be defined as an angular range of the roller in which the substrate contacts the curved substrate support surface during guiding of the substrate, and may correspond to a wrap angle of the roller. For example, the wrap angle of the roller may be 120° or more, in particular 180° or more, or even 270° or more. According to some embodiments, which may be combined with other embodiments described herein, the roller 100 is cylindrical and has a length L, where 0.5 m≦L≦8.5 m. The roller 100 may also have a diameter D, where 0.2 m≦D≦3.0 m, in particular 0.2 m≦D≦2.0 m, for example D=0.4 m±0.2 m. The roller is thus advantageously configured to guide and transport wide flexible substrates.

[0019]

[0018] 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 substrate described herein can be made of or include materials such as PET, HC-PET, PE, PI, PU, ​​TaC, OPP, BOOP, CPP, one or more metals (such as copper), paper, combinations thereof, and already coated substrates such as hard-coated PET (HC-PET, HC-TaC), etc. In some embodiments, the flexible substrate is a COP substrate provided with index matching (IM) layers on both sides thereof. For example, the thickness of the substrate can be 1 μm to 1 mm, in particular 500 μm or less, or even 200 μm or less. The substrate width WS can be 0.3 m≦W≦8 m. The substrate can be a transparent substrate or an opaque substrate.

[0020]

[0019] In the present disclosure, the "body" of the roller may be understood as a cylindrical body, in particular a cylindrical shell body of a solid material. Typically, the body is made of a material having a high thermal conductivity λ, in particular λ≧50 W / (m·K), more particularly λ≧100 W / (m·K). For example, the body may be composed of a material containing copper, such as a copper alloy. In particular, the body may be made of copper. It should be understood that the body may alternatively be made of other suitable materials having a high thermal conductivity λ.

[0021]

[0020] In the present disclosure, a "coolant supply" may be understood as an apparatus or system configured to provide a coolant. Thus, a coolant supply as described herein typically includes a coolant and piping for delivering the coolant. More specifically, a coolant supply may include a closed loop refrigeration system having a heat sink, a pressure reducer, a pressure booster, and a heat rejector. Generally, the heat sink is provided by piping provided at the site to be cooled, for example, at one or more components of the roller as described herein. In the present disclosure, a "coolant" may be understood as a cooling fluid, in particular, a non-compressible cooling fluid capable of providing a cooling temperature in the range of -100°C to +80°C, in particular -50°C to +80°C, more specifically -30°C to +80°C. Moreover, the coolant is typically non-toxic and does not react with lithium. For example, the coolant may be oil.

[0022] In the present disclosure, a "part of a roller" can be understood as a part of a roller having a substrate support surface. Typically, a "part of a roller" as described herein can be understood as a cylindrical portion of a cylindrical body as described herein.

[0023] 1, according to an embodiment, which may be combined with other embodiments described herein, a first coolant supply 110 is configured to provide a first coolant at a first temperature T1. A second coolant supply 120 is configured to provide a second coolant at a second temperature T2, which is different from the first temperature T1. In particular, the first temperature T1 is lower than the second temperature T2.

[0024]

[0023] As shown diagrammatically in FIG. 1, according to an embodiment that can be combined with other embodiments described herein, the first coolant supply 110 includes a first heat sink 161 for removing heat from the first portion 101 of the roller 100. Typically, the second coolant supply 120 includes a second heat sink 162 for removing heat from the second portion 102 of the roller 100. Furthermore, as exemplarily shown in FIG. 1, the second coolant supply 120 includes a third heat sink 163 for removing heat from the third portion 103 of the roller 100. For example, the "heat sink" described herein can be provided by piping that is in contact with the portion of the roller that is to be cooled specifically. For example, the piping of the heat sink can include a winding provided around the central rotation axis 111 of the roller. To simplify the drawing, only the upper part of FIG. 1 shows the coolant supplies, i.e. the first coolant supply 110 and the second coolant supply 120. However, typically, the complete cylindrical portions, e.g., first portion 101, second portion 102 and third portion 103 shown in Figure 1, may be cooled by their respective coolant supplies as described herein, and therefore the illustration of the top portion of Figure 1 may also be applied to the bottom portion of Figure 1.

[0025]

[0024] As shown diagrammatically in Fig. 1, according to an embodiment that can be combined with other embodiments described herein, the first coolant supply 110 includes a first coolant pipe 141 and the second coolant supply 120 includes a second coolant pipe 142, both connected to a common coolant outlet pipe 150. In particular, as exemplarily shown in Fig. 1, the coolant outlet pipes extend along the direction of the central rotation axis 111 of the roller.

[0026]

[0025] With exemplarily reference to Fig. 2, according to an embodiment that can be combined with other embodiments described herein, the roller further comprises a third coolant supply 130 for cooling the fourth portion 104 and the fifth portion 105 of the roller 100. Typically, the second portion 102 is provided between the first portion 101 and the fourth portion 104. The third portion 103 can be provided between the first portion 101 and the fifth portion 105. Usually, the fourth portion 104 is a fourth cylindrical portion of the cylindrical body 106 of the roller 100. Thus, typically, the fifth portion 105 is a fifth cylindrical portion of the cylindrical body 106.

[0027]

[0026] As shown diagrammatically in Figure 2, according to an embodiment that may be combined with other embodiments described herein, the third coolant supply 130 includes a fourth heat sink 164 for removing heat from the fourth portion 104 of the roller 100. Furthermore, typically, the third coolant supply 130 includes a fifth heat sink 165 for removing heat from the fifth portion 105 of the roller 100. Similarly, as in Figure 1, to simplify the illustration, only the lower portion of Figure 2 shows the third coolant supply. However, it should be understood that the illustration of the third coolant supply 130 shown in the lower portion of Figure 2 generally also applies to the upper portion of Figure 2.

[0028]

[0027] As exemplarily shown in Fig. 2, according to an embodiment that can be combined with other embodiments described herein, the third coolant supply unit 130 includes a third coolant pipe 143 connected to a coolant outlet pipe 150 extending along the direction of the central rotation axis 111 of the roller 100. In particular, as exemplarily shown in Fig. 2, each of the first coolant pipe 141, the second coolant pipe 142 and the third coolant pipe 143 is connected to a common coolant outlet pipe.

[0029] According to an embodiment, which may be combined with other embodiments described herein, the third coolant supply 130 is configured to provide a third coolant at a third temperature T3 different from the first temperature T1 and the second temperature T2. In particular, the third temperature T3 may be lower than the first temperature T1. Additionally or alternatively, the third temperature T3 may be lower than the second temperature T2.

[0030] 3, a vacuum processing apparatus 200 according to the present disclosure is described. According to an embodiment that may be combined with other embodiments described herein, the vacuum processing apparatus 200 includes a processing chamber 220 including a plurality of processing units 221. The plurality of processing units 221 includes at least one deposition unit. Furthermore, the vacuum processing apparatus 200 includes a roller 100 according to any embodiment described herein for guiding a flexible substrate through the plurality of processing units 221.

[0031]

[0030] As shown diagrammatically in Fig. 3, the roller 100 can be connected to a coolant supply 225. Typically, the coolant supply 225 is configured to provide two or more coolants of different temperatures. In particular, the coolant supply 225 is configured to provide a first coolant having a first temperature T1 and a second coolant having a second temperature T2 different from the first temperature T1. Typically, the first temperature T1 is lower than the second temperature T2. It should be understood that the coolant supply 225 can furthermore be configured to provide a third coolant having a third temperature T3, the third temperature T3 being different from the first temperature T1 and the second temperature T2. For example, the third temperature T3 can be lower than the first temperature T1 and / or lower than the second temperature T2.

[0032] As exemplarily shown in FIG. 3, typically the vacuum processing apparatus 200 is a roll-to-roll processing system. The roller 100 according to any embodiment described herein may be a processing drum or a coating drum of the vacuum processing apparatus. According to an embodiment, which may be combined with other embodiments described herein, the vacuum processing apparatus 200 includes a first spool chamber 210 that accommodates a storage spool 212 for providing the flexible substrate 10. The vacuum processing apparatus 200 also includes a processing chamber 220 downstream of the first spool chamber 210. Typically, the processing chamber 220 is a vacuum chamber and includes a plurality of processing units 221. The plurality of processing units 221 includes at least one deposition unit. Thus, in the present disclosure, a "processing chamber" can be understood as a chamber having at least one deposition unit for depositing a material on a substrate. Thus, the processing chamber is also referred to as a deposition chamber. The term "vacuum" as used herein can be understood in the sense of a technical vacuum, for example having a vacuum pressure below 10 mbar. Typically, the pressure in the vacuum chamber described herein is below 10 mbar. -5 Millibar to about 10 -8 Between millibars, or more generally, 10 -5 mbar~10 -7 mbar, more typically about 10 -6 Millibar to about 10 -7 It may be between millibars.

[0033]

[0032] As exemplarily shown in FIG. 3, the multiple processing units may be arranged in a circumferential direction around the roller 100. As the roller 100 rotates, the flexible substrate 10 is guided through the processing units facing the curved substrate support surface of the roller, thereby allowing the surface of the flexible substrate to be processed while passing through the processing units at a predetermined speed. For example, the multiple 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 can be a sputter deposition unit, such as an AC (alternating current) sputter source or a DC (direct current) sputter source, an RF (radio frequency) sputter source, an MF (medium frequency) sputter source, a pulsed sputter source, a pulsed DC sputter source, a magnetron sputter source, a reactive sputter source, a CVD deposition unit, a PECVD deposition unit, a PVD deposition unit, or another suitable deposition unit. It should be understood that the deposition units described herein are generally adapted to deposit thin films on flexible substrates, for example to form flexible display devices, touch screen device components, or other electronic or optical devices. The deposition units described herein may be configured to deposit at least one material selected from the group of conductive, semiconductive, dielectric, or insulating materials.

[0034] 3, the vacuum processing apparatus 200 may further include a second spool chamber 250 disposed downstream of the processing chamber 220. The second spool chamber 250 contains a take-up spool 252 for taking up the flexible substrate 10 after processing.

[0035]

[0034] With exemplarily reference to the block diagram shown in FIG. 4A, a method 300 of cooling a roller for guiding a flexible substrate according to the present disclosure is described. According to an embodiment, which may be combined with other embodiments described herein, the method 300 includes cooling the first portion 101 of the roller (100) (represented by block 310 in FIG. 4A) by supplying a first coolant to the first portion 101 of the roller (100) (represented by block 311 in FIG. 4A). Furthermore, the method 300 includes cooling the second portion 102 and the third portion 103 of the roller 100 (represented by block 320 in FIG. 4A) by supplying a second coolant to the second portion 102 and the third portion 103 (represented by block 321 in FIG. 4A). As described herein, the first portion 101 is provided between the second portion 102 and the third portion 103. In particular, the first coolant has a first temperature T1 and the second coolant has a second temperature T2 different from the first temperature T1. In particular, the first temperature T1 is lower than the second temperature T2.

[0036]

[0035] Referring exemplarily to Fig. 4B, according to an embodiment that may be combined with other embodiments described herein, the method 300 includes cooling the fourth and fifth portions 104 and 105 of the roller 100 (represented by block 330 in Fig. 4B) by supplying a third coolant to the fourth and fifth portions 104 and 105 of the roller 100 (represented by 331 in Fig. 4B). As described herein, the second portion 102 is typically provided between the first and fourth portions 101 and 104. The third portion 103 is typically provided between the first and fifth portions 101 and 105. More specifically, the third coolant typically has a third temperature T3 that is different from the first and second temperatures T1 and T2. In particular, the third temperature T3 may be lower than the first temperature T1 and / or lower than the second temperature T2.

[0037] According to an embodiment that may be combined with other embodiments described herein, the method 300 further includes modifying the shape of the roller 100 (represented by block 340 in FIG. 4B) by thermally expanding (represented by block 341 in FIG. 4B) or thermally contracting (represented by block 342 in FIG. 4B) at least a portion of the roller 100. In particular, modifying the shape of the roller may include providing a convex roller shape or providing a concave roller shape. For example, the concave roller shape is obtained by cooling an axially central portion of the roller (e.g., a first portion 101 as described herein) to a lower temperature than the side portions of the roller (e.g., a second portion 102 and a third portion 103 as described herein). Providing a concave roller shape may be beneficial because it may achieve elongation of the flexible substrate, which is beneficial for avoiding wrinkles.

[0038] According to an embodiment, which may be combined with other embodiments described herein, the method 300 includes using a roller 100 according to any embodiment described herein.

[0039]

[0038] Although not explicitly described herein, it should be understood that more than two individually controllable coolant supplies may be provided, for example, by providing a fourth and fifth coolant supply configured similarly to the second and third coolant supplies, ten separate portions of the roller may be cooled.

[0040] In view of the embodiments described herein, it should be appreciated that according to one aspect of the disclosure, there may be provided a method of manufacturing a coated flexible substrate, the method including using at least one of the rollers 100 according to any embodiment described herein, and the present invention provides a vacuum processing apparatus 200 according to any embodiment described herein, and a method 300 of cooling the roller according to any embodiment described herein.

[0041]

[0040] In view of the above, in comparison to the state of the art, the embodiments described herein provide improved flexible substrate transport, with improved roller cooling and improved substrate cooling, advantageously allowing thinner and wider flexible substrates to be processed, resulting in improved processing results.

[0042]

[0041] While the foregoing description is directed to embodiments, other and further embodiments may be devised without departing from the basic scope of the disclosure, the scope of which is defined by the appended claims.

Claims

1. A roller (100) for transporting a flexible substrate, comprising a first coolant supply (110) for cooling a first portion (101) of the roller (100) and a second coolant supply (120) for cooling a second portion (102) and a third portion (103) of the roller (100), the first portion (101) being disposed between the second portion (102) and the third portion (103).

2. The roller (100) of claim 1, wherein the first portion (101) is an axially intermediate portion of a body (106) of the roller (100).

3. 3. The roller (100) of claim 1 or 2, wherein the first coolant supply (110) is configured to provide a first coolant at a first temperature (T1) and the second coolant supply (120) is configured to provide a second coolant at a second temperature (T2) different from the first temperature (T1).

4. 3. The roller (100) of claim 1 or 2, wherein the first coolant supply (110) comprises a first coolant pipe (141) and the second coolant supply (120) comprises a second coolant pipe (142), the first coolant pipe (141) and the second coolant pipe (142) are both connected to a common coolant outlet pipe (150), the coolant outlet pipe extending along a central rotation axis (111) of the roller.

5. 3. The roller (100) of claim 1 or 2, wherein the first portion (101) is a first cylindrical portion of a cylindrical body (106) of the roller, the second portion (102) is a second cylindrical portion of the body (106), and the third portion (103) is a third cylindrical portion of the body (106).

6. 3. The roller (100) of claim 1 or 2, further comprising a third coolant supply (130) for cooling a fourth portion (104) and a fifth portion (105) of the roller (100), the second portion (102) being provided between the first portion (101) and the fourth portion (104), and the third portion (103) being provided between the first portion (101) and the fifth portion (105).

7. A roller (100) as described in claim 6, wherein the first coolant supply (110) includes a first coolant pipe (141), the second coolant supply (120) includes a second coolant pipe (142), the first coolant pipe (141) and the second coolant pipe (142) are both connected to a common coolant outlet pipe (150), and the third coolant supply (130) includes a third coolant pipe (143) connected to the coolant outlet pipe extending along the direction of the central rotation axis (111) of the roller.

8. 7. The roller (100) of claim 6, wherein the fourth portion (104) is a fourth cylindrical portion of a cylindrical body (106) of the roller (100) and the fifth portion (105) is a fifth cylindrical portion of the cylindrical body (106).

9. A roller (100) as described in claim 6, wherein the first coolant supply (110) is configured to provide a first coolant at a first temperature (T1), the second coolant supply (120) is configured to provide a second coolant at a second temperature (T2) different from the first temperature (T1), and the third coolant supply (130) is configured to provide a third coolant at a third temperature (T3) different from the first temperature (T1) and the second temperature (T2).

10. The roller (100) of claim 2, wherein the body (106) is a cylinder made of a material including copper.

11. A vacuum processing apparatus (200) for processing a flexible substrate (10), comprising: a processing chamber (220) including a plurality of processing units (221) including at least one deposition unit; A roller (100) according to claim 1 or 2 for guiding the flexible substrate through the plurality of processing units (221); wherein said roller (100) is connected to a coolant supply (225).

12. 12. The vacuum processing apparatus (200) of claim 11, wherein the coolant supply (225) is configured to provide at least a first coolant having a first temperature (T1) and a second coolant having a second temperature (T2) different from the first temperature (T1).

13. A method (300) for cooling a roller (100) for guiding a flexible substrate, comprising: cooling (310) a first portion (101) of the roller (100) by providing (311) a first coolant to the first portion (101); and cooling (320) the second portion (102) and the third portion (103) of the roller (100) by providing (321) a second coolant to the second portion (102) and the third portion (103), wherein the first portion (101) is disposed between the second portion (102) and the third portion (103), the first coolant having a first temperature (T1), and the second coolant having a second temperature (T2) different from the first temperature (T1).

14. 14. The method (300) of claim 13, further comprising cooling (330) the fourth (104) and fifth (105) portions of the roller (100) by supplying (331) a third coolant to the fourth (104) and fifth (105) portions of the roller (100), wherein the second portion (102) is disposed between the first portion (101) and the fourth portion (104), and the third portion (103) is disposed between the first portion (101) and the fifth portion (105), and the third coolant has a third temperature (T3), the third temperature (T3) being different from the first temperature (T1) and the second temperature (T2).

15. 15. The method (300) of claim 13 or 14, further comprising altering (340) a shape of the roller (100) by thermally expanding (341) or thermally contracting (342) at least a portion of the roller (100), wherein altering (340) the shape of the roller (100) comprises providing a convex roller shape or providing a concave roller shape.

Images