FIELD

[0001] Embodiments of the present disclosure relate to an apparatus for supporting a flexible substrate in a vacuum processing chamber, a processing apparatus configured for layer deposition on a flexible substrate, and a method for supporting a flexible substrate on a coating drum. Embodiments of the present disclosure particularly relate to thin-film processing apparatuses, for example, to an apparatus for processing a flexible substrate, and more particularly to roll-to-roll (R2R) systems.

BACKGROUND

[0002] Processing of flexible substrates, such as plastic films or foils, can be employed in the packaging industry, semiconductor industry and other industries. The processing may include a coating of the flexible substrate with one or more coating materials, such as metals, semiconductor materials and dielectric materials. The processing can further include other processing aspects, such as etching. Processing apparatuses performing the processing aspects can include a coating drum coupled to a system for transportation of the flexible substrate. Such roll-to-roll systems can provide a high throughput.

[0003] A coating process, such as a sputter deposition process, a thermal evaporation process, or a chemical vapor deposition (CVD) process, can be utilized for depositing thin layers of the coating materials onto a flexible substrate. During the coating process, a temperature of the flexible substrate can be increased. The flexible substrate can be damaged due to the increased temperature. In particular, the edges of the flexible substrate can experience heat damages. For example, the edges of the flexible substrate can develop wrinkles. [0004] In view of the above, new apparatuses for supporting a flexible substrate in a vacuum processing chamber, processing apparatuses configured for layer deposition on a flexible substrate, and methods for supporting a flexible substrate on a coating drum, that overcome at least some of the problems in the art, are beneficial. Specifically, apparatuses, processing apparatuses and methods are beneficial that can avoid heat damage of the flexible substrate, such as heat damage of edges of the flexible substrate.

SUMMARY [0005] In light of the above, an apparatus for supporting a flexible substrate in a vacuum processing chamber, a processing apparatus configured for layer deposition on a flexible substrate, and a method for supporting a flexible substrate on a coating drum are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings. [0006] According to an aspect of the present disclosure, an apparatus for supporting a flexible substrate in a vacuum processing chamber is provided. The apparatus includes a coating drum rotatable around a rotational axis, wherein the coating drum has a support surface configured for supporting the flexible substrate, wherein the support surface is symmetrical with respect to the rotational axis, and wherein a first distance between the rotational axis and a center portion of the support surface in a direction perpendicular to the rotational axis is smaller than a second distance between the rotational axis and a periphery of the support surface.

[0007] According to another aspect of the present disclosure, a processing apparatus configured for layer deposition on a flexible substrate is provided. The processing apparatus includes a vacuum processing chamber, the apparatus for supporting the flexible substrate according to the present disclosure in the vacuum processing chamber, and one or more processing tools selected from the group consisting of a deposition source and an etching tool, wherein the one or more processing tools are positioned adjacent to the coating drum of the apparatus. [0008] According to yet another aspect of the present disclosure, a method for supporting a flexible substrate on a coating drum is provided. The method includes supporting the flexible substrate on a support surface of the coating drum, wherein the support surface is symmetrical with respect to a rotational axis of the coating drum, and wherein a distance between the rotational axis and the support surface in a direction perpendicular to the rotational axis varies along the rotational axis, and applying a tension at edge portions of the flexible substrate by the support surface.

[0009] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the disclosure are also directed at methods for operating the described apparatus. The methods for operating the described apparatus include method aspects for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:

FIG. 1 shows a schematic cross-sectional view of an apparatus for supporting a flexible substrate in a vacuum processing chamber according to embodiments described herein;

FIG. 2 shows another schematic cross-sectional view of the apparatus of FIG.1 ;

FIG. 3 shows a schematic view of an apparatus supporting a flexible substrate according to embodiments described herein; shows a schematic cross-sectional view of an apparatus for supporting a flexible substrate in a vacuum processing chamber according to embodiments described herein; shows a schematic cross-sectional view of an apparatus for supporting a flexible substrate in a vacuum processing chamber according to further embodiments described herein; shows a schematic cross-sectional view of an apparatus for supporting a flexible substrate in a vacuum processing chamber according to yet further embodiments described herein; shows a schematic view of a processing apparatus configured for layer deposition on a flexible substrate according to embodiments described herein; and shows a flow chart of a method for supporting a flexible substrate on a coating drum according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS [0011] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. 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. [0012] During substrate processing, such as during a coating process, a temperature of the flexible substrate can be increased. The flexible substrate can be damaged due to the increased temperature. In particular, the edges of the substrate can experience heat damages, e.g., the edges of the substrate can become wavy or wrinkled. According to the present disclosure, the coating drum has a varying diameter to locally increase a tension of the flexible substrate. As an example, the varying diameter can increase the tension of the substrate towards and/or at the substrate edges. The local increase in the tension of the flexible substrate allows for a reduction or even avoidance of heat damages of the flexible substrate. Specifically, increasing the tension at the substrate edges can prevent the substrate edges from becoming wavy or wrinkled.

[0013] The term "tension" as used throughout the present disclosure can be understood in the sense of a "pulling force" exerted on the flexible substrate by the curved support surface. Specifically, "tension" is the opposite of "compression".

[0014] The term "flexible substrate" as used herein shall embrace flexible substrates such as a web or a foil. It is noted here that a flexible substrate as used within the embodiments described herein can be characterized in that it is bendable.

[0015] FIG. 1 shows a cross-sectional schematic view of an apparatus 100 for supporting a flexible substrate in a vacuum processing chamber according to embodiments described herein having a coating drum rotatable around a rotational axis 105. Specifically, FIG. 1 shows a cross-sectional view of the apparatus 100 in a plane parallel to the rotational axis 105. FIG. 2 shows another cross-sectional schematic view of the apparatus of FIG.1 in a plane perpendicular to the rotational axis 105.

[0016] The apparatus 100 includes, or is, a coating drum rotatable around a rotational axis 105. The coating drum has a support surface 110 configured for supporting the flexible substrate, wherein the support surface 110 is symmetrical with respect to the rotational axis 105. As an example, the support surface 110 is substantially rotationally symmetric around the rotational axis 105. The term "substantially" shall account for manufacturing tolerances of the coating drum, and specifically manufacturing tolerances of the support surface 110. A first distance 120 between the rotational axis 105 and a center portion 112 of the support surface 110 in a direction perpendicular to the rotational axis 105 is smaller than a second distance 122 between the rotational axis 105 and a periphery of the support surface 110.

[0017] The coating drum can also be referred to as "substrate support". Specifically, the coating drum can be configured to support the flexible substrate during substrate processing, for example, a coating process, in the vacuum processing chamber. Specifically, the flexible substrate can be moved through a coating area of the vacuum processing chamber provided at the coating drum and corresponding to positions of one or more deposition sources. During operation, the coating drum rotates around the rotational axis 105 such that the flexible substrate is moved forward or backward. As an example, the coating drum is configured to rotate clockwise or counterclockwise around the rotational axis 105 for transportation of the flexible substrate.

[0018] The term "support surface" as used throughout the present disclosure refers to a surface configured to contact the flexible substrate for supporting the flexible substrate. Specifically, the support surface is different from other surface portions of the coating drum that are not intended or provided to contact or support the flexible substrate.

[0019] According to some embodiments, which can be combined with other embodiments described herein, the support surface 110 can be provided by a circumferential surface, for example, an outer circumferential surface, of the coating drum. In some implementations, the coating drum can be substantially cylindrical, wherein the support surface 110 can be provided by the circumferential surface of the substantially cylindrical coating drum. The term "substantially cylindrical" shall take account for the varying distance between the rotational axis 105 of the coating drum and the support surface 110.

[0020] According to some embodiments, which can be combined with other embodiments described herein, the periphery of the support surface 110 is a boundary (for example, an edge or end) of the support surface 110 in a direction parallel to the rotational axis 105. As an example, the periphery of the support surface 110 includes a first boundary 114 and a second boundary 116 opposite the first boundary 114. The support surface 110 can extend between the first boundary 114 and the second boundary 116. In the cross- sectional view of FIG. 1, the first boundary 114 can be a left edge or left end of the support surface 110. The second boundary 116 can be a right edge or right end of the support surface 110.

[0021] The support surface 110 has a width 124 in a direction parallel to the rotational axis 105. The width 124 can be defined between the peripheries of the support surface 110, for example, the first boundary 114 and the second boundary 116. The width 124 of the support surface 110 can be at least 300 mm, specifically at least 1 m, and more specifically at least 3 m. As an example, the width of the support surface 110 can be in a range between 300 mm and 5 m, and can more specifically be in a range between 400 mm and 4.5 m.

[0022] The center portion 112 of the support surface 110 can be at, or around, a center or midpoint between the peripheries of the support surface 110 in the direction parallel to the rotational axis 105. As an example, the center portion 112 can be at, or around, a center or midpoint between the first boundary 114 and the second boundary 116.

[0023] The first distance 120 and the second distance 122 can be defined or measured along a line connecting the rotational axis 105 and the support surface 110. The line can be perpendicular to the rotational axis 105. It is to be understood that the line can, in some implementations, be non-perpendicular to the support surface 110 due to the curvature of the support surface in the direction parallel to the rotational axis 105.

[0024] According to some embodiments, which can be combined with other embodiments described herein, the first distance 120 is at least 90% of the second distance 122, specifically at least 95% of the second distance 122, and more specifically at least 99% of the second distance 122. The difference between the first distance 120 and the second distance 122 provides for a locally increased tension in the flexible substrate.

[0025] In some implementations, the coating drum or support surface 110 can have a diameter with respect to the rotational axis 105. The diameter can be measured or defined in a plane perpendicular to the rotational axis 105. The diameter varies along at least a part of the rotational axis 105 to provide for the first distance 120 and the second distance 122. The diameter can also be referred to as "local diameter". The local diameter can be twice the (local) distance between the rotational axis 105 and the support surface 110. As an example, a maximum diameter of the coating drum or support surface 110 can be twice the second distance 122. A minimum diameter of the coating drum or support surface 110 can be twice the first distance 120.

[0026] According to some embodiments, which can be combined with other embodiments described herein, the diameter or maximum diameter of the coating drum at the periphery of the support surface 110 is at least 300 mm, specifically at least 0.5 m, and more specifically at least 1 m. In particular, the diameter or maximum diameter of the coating drum at the periphery of the support surface is at least 0.5 m. The diameter or maximum diameter can be in a range between 300 mm and 3 m, specifically in a range between 400 mm and 2 m, and more specifically in a range between 400 mm and 1.8 m. [0027] According to some embodiments, which can be combined with other embodiments described herein, a diameter difference is in a range of 0.005% to 5% of the width 124 of the support surface 110, specifically in a range of 0.01% to 2% of the width 124 of the support surface 110, and more specifically in a range of 0.01% to 0.5% of the width 124 of the support surface 110. The diameter difference can be defined as a difference between the maximum diameter and the minimum diameter of the support surface 110. As an example, the diameter difference can be defined as the difference between the diameter of the support surface 110 at the periphery of the support surface 110 (e.g., the maximum diameter) and the diameter of the support surface 110 at the center portion 112 of the support surface 110 (e.g., minimum diameter). [0028] According to some embodiments, which can be combined with other embodiments described herein, a diameter difference per meter of the width of the support surface 110 is less than 5 mm, specifically less than 2 mm, and more specifically less than 1 mm.

[0029] According to some embodiments, which can be combined with other embodiments described herein, the distance, such as the first distance 120 and the second distance 122, between the rotational axis 105 and the support surface 110 is substantially constant in a plane perpendicular to the rotational axis 105. Specifically, the distance or diameter changes along the rotational axis 105, and does not change in a plane perpendicular to the rotational axis 105. [0030] According to some embodiments, which can be combined with other embodiments described herein, the support surface 110 has one or more concavely shaped portions. Specifically, the support surface 110 can have a cross section in a plane parallel to rotational axis 105 with the rotational axis 105 lying in the plane (e.g., FIG. 1). The outer circumference of the cross section of the support surface 110 can have the one or more concavely shaped portions. The concave coating drum (also referred to as "concave roller") can increase the tension at the edges of the flexible substrate. Heat damages on the edges of the flexible substrate can be reduced or even avoided.

[0031] The terms "concavely shaped" and "concave" as used throughout the present disclosure are to be understood in the sense that the support surface is curved inwardly with respect to the rotational axis 105. As an example, the distance between the support surface 110 and the rotational axis 105 (or diameter) of the support surface 110 can continuously and/or non-linearly decrease in a direction from the peripheries of the support surface 110 towards the center portion 112. The distance or diameter of the support surface 110 can continuously and/or non-linearly increase in a direction from the center portion 112 towards the peripheries of the support surface 110, such as the first boundary 114 and the second boundary 116.

[0032] In some implementation, as illustrated in FIG. 1, the support surface 110 consists of the concavely shaped portion. In other words, the entire support surface 110 is concavely shaped. In other implementations, the support surface 110 has two or more concavely shaped portions that can be sequentially arranged in a direction parallel to the rotational axis 105.

[0033] The one or more concavely shaped portions can provide at least one of the periphery and the center portion 112 of the support surface 110. As an example, the one or more concavely shaped portions can provide the first boundary 114, the center portion 112 and the second boundary 116 of the support surface 110.

[0034] In some implementations, the coating drum includes a cooling device configured to cool the support surface 110, for example, during substrate processing. The cooling of the support surface 110 can further reduce heat damages of the flexible substrate, for example, during a coating process. According to some embodiments, the coating drum can be a double-walled coating drum. A cooling liquid can be provided between the two walls of the double-ward coating drum. The two walls can be an inner wall and an outer wall, wherein the outer wall can provide the support surface 110.

[0035] FIG. 3 shows a schematic view of the apparatus 100 supporting a flexible substrate 10 according to embodiments described herein. The coating drum is configured to support the flexible substrate 10 during substrate processing, for example, a coating process, in the vacuum processing chamber. Specifically, the flexible substrate 10 can be moved through a coating area provided at the coating drum and corresponding to positions of one or more deposition sources (not shown). During operation, the coating drum rotates, for example, clockwise or counterclockwise, around the rotational axis 105 such that the flexible substrate 10 is moved forward or backward.

[0036] The coating drum having the varying diameter can locally increase a tension in the substrate. For example, the varying diameter can increase the tension of the substrate towards the substrate edges. The local increase in the tension of the flexible substrates allows for a reduction or even avoidance of heat damages of the flexible substrate. Specifically, increasing the tension at the substrate edges can prevent the substrate edges from becoming wavy or wrinkled. It is noted that the present disclosure is not limited to increasing the tension at the substrate edges. The diameter of the coating drum can be varied such that the tension is (locally) increased at selected positions of the flexible substrates, e.g., where heat damages can occur.

[0037] FIG. 4 shows a schematic view of an apparatus 400 for supporting a flexible substrate in a vacuum processing chamber according to embodiments described herein.

[0038] According to some embodiments, which can be combined with other embodiments described herein, the support surface has one or more linearly inclined portions that are linearly inclined in a direction parallel to the rotational axis 105. Specifically, the support surface can have a cross section in a plane parallel to the rotational axis 105 with the rotational axis 105 lying in the plane (e.g., FIG. 4). The outer circumference of the cross section of the support surface can have the one or more linearly inclined portions. [0039] In some implementations, the one or more linearly inclined portions include a first linearly inclined portion 410 and a second linearly inclined portion 412, wherein the first linearly inclined portion 410 and the second linearly inclined portion 412 are oppositely inclined. As an example, the distance between the support surface and the rotational axis 105 can linearly increase from the center portion 414 towards each of the peripheries of the support surface, such as the first boundary 415 and the second boundary 416. Specifically, the first linearly inclined portion 410 and the second linearly inclined portion 412 can be mirror-inverted with respect to each other. According to some embodiments, the first linearly inclined portion 410 and the second linearly inclined portion 412 together can form a V-shape.

[0040] According to some embodiments, the first linearly inclined portion 410 and the second linearly inclined portion 412 are connected to each other, for example, in the center portion 414 of the support surface. In particular, the connection portion between the first linearly inclined portion 410 and the second linearly inclined portion 412 can provide the center portion 414.

[0041] In some implementations, the first linearly inclined portion 410 can be a first truncated cone, and the second linearly inclined portion 412 can be a second truncated cone. The first truncated cone and the second truncated cone can have substantially the same shape. Specifically, the first truncated cone and the second truncated cone can be mirror-inverted with respect to each other.

[0042] FIG. 5 shows a schematic view of an apparatus 500 for supporting a flexible substrate in a vacuum processing chamber according to further embodiments described herein.

[0043] According to some embodiments, which can be combined with other embodiments described herein, the support surface has one or more straight portions 520 substantially parallel to the rotational axis 105. Specifically, a distance between the rotational axis 105 and the one or more straight portions 520 of the support surface can be substantially constant along (or parallel to) the rotational axis 105. The distance can be measured in the direction perpendicular to the rotational axis 105. The term "substantially parallel" relates to a substantially parallel orientation e.g. of the rotational axis 105 and the one or more straight portions 520 of the support surface, wherein a deviation of a few degrees, e.g. up to 5° or even up to 10°, from an exact parallel orientation is still considered as "substantially parallel".

[0044] The one or more straight portions 520 can have a width 522 in the direction parallel to the rotational axis 105. The width 522 of the one or more straight portions 520 can be less than 25%, less than 10%, and more specifically less than 5% of the total width of the support surface (indicated with reference numeral 124 in FIG. 1).

[0045] In some implementations, the one or more straight portions 520 provide the center portion of the support surface. As an example, the one or more straight portions 520 can be provided between two or more portions having the varying distances with respect to the rotational axis 105. Specifically, the one or more straight portions 520 can be provided between two or more linearly inclined portions, such as the first linearly inclined portion 410 and the second linearly inclined portion 412.

[0046] FIG. 6 shows a schematic view of an apparatus 600 for supporting a flexible substrate in a vacuum processing chamber according to yet further embodiments described herein. The apparatus 600 has the one or more straight portions 520 described above with reference to FIG. 5. In the example of FIG. 6, the one or more straight portions 520 are provided between two or more curved portions, such as a first curved portion 610 and a second curved portion 612. The one or more curved portions can be at least one of non- linear portions and concavely shaped portions.

[0047] In some implementations, the distance between the one or more curved portions of the support surface and the rotational axis 105 can non-linearly increase from the center portion (for example, provided by the one or more straight portions 520) towards each of the peripheries of the support surface, such as the first boundary 615 and the second boundary 616. Specifically, the first curved portion 610 and the second curved portion 612 can be mirror-inverted with respect to each other.

[0048] FIG. 7 shows a schematic view of a processing apparatus 700, such as a roll-to- roll deposition apparatus, configured for layer deposition on a flexible substrate 10 in a vacuum processing chamber according to embodiments described herein. [0049] The processing apparatus 700 includes the apparatus for supporting a flexible substrate in a vacuum processing chamber according to the embodiments described herein, and one or more processing tools selected from the group consisting of a deposition source and an etching tool. The one or more processing tools are positioned adjacent to the coating drum 710 of the apparatus. The coating drum 710 has the varying diameter, as it is indicated with the dashed line 711.

[0050] The processing apparatus 700 can include at least three chamber portions, such as a first chamber portion 702, a second chamber portion 704 and a third chamber portion 706. The third chamber portion 706 or a combination of the second chamber portion 704 and the third chamber portion 706 can be configured as the vacuum processing chamber of the present disclosure. The one or more processing tools, such as one or more deposition sources 730 and one or more etching tools 732, can be provided in the third chamber portion 706.

[0051] The flexible substrate 10 is provided on a first roll 764, e.g. having a winding shaft. The flexible substrate 10 is unwound from the first roll 764 as indicated by the substrate movement direction shown by arrow 1. A separation wall 708 is provided for separation of the first chamber portion 702 and the second chamber portion 704. The separation wall 708 can further be provided with gap sluices 709 for having the flexible substrate 10 pass therethrough. A vacuum flange 705 between the second chamber portion 704 and the third chamber portion 706 may be provided with openings to take up the one or more processing tools, such as the one or more deposition sources 730 and the one or more etching tools 732.

[0052] The flexible substrate 10 is moved through the deposition areas (or coating areas) provided at the coating drum 710 and corresponding to positions of the one or more deposition sources 730. During operation, the coating drum 710 rotates around the rotational axis 105 such that the flexible substrate 10 moves in the direction of arrow 1. According to some embodiments, the flexible substrate 10 is guided via one, two or more rollers from the first roll 764 to the coating drum 710 and from the coating drum 710 to a second roll 765, e.g. having a winding shaft, on which the flexible substrate 10 is wound after processing thereof. [0053] In some implementations, the first chamber portion 702 is separated in an interleaf chamber portion unit 701 and a substrate chamber portion unit 703. Interleaf rolls 766 and interleaf rollers 767 can be provided as a modular element of the processing apparatus 700. The processing apparatus 700 can further include a pre-heating unit 740 to heat the fiexible substrate 10. Further, additionally or alternatively a pre-treatment plasma source 742, e.g., an RF plasma source can be provided to treat the fiexible substrate 10 with a plasma prior to entering the third chamber portion 706.

[0054] According to yet further embodiments, which can be combined with other embodiments described herein, optionally an optical measurement unit 744 for evaluating the result of the substrate processing and/or one or more ionization units 746 for adapting the charge on the fiexible substrate 10 can be provided.

[0055] FIG. 8 shows a flow chart of a method 800 for supporting a flexible substrate on a coating drum according to embodiments described herein. The method can be implemented using the apparatus for supporting a flexible substrate in a vacuum processing chamber and the processing apparatus configured for layer deposition on a flexible substrate according to the embodiments described herein.

[0056] The method includes in block 810 a supporting of the flexible substrate on a support surface of the coating drum, wherein the support surface is symmetrical with respect to a rotational axis of the coating drum, and wherein a distance between the rotational axis and the support surface in a direction perpendicular to the rotational axis varies along the rotational axis. The method includes in block 820 an application of a tension at edge portions of the flexible substrate by the support surface.

[0057] According to some embodiments, the method 800 further includes a rotating of the coating drum around the rotational axis to move the fiexible substrate through a processing area provided in the vacuum processing chamber. In some implementations, the method 800 includes a processing of the flexible substrate in the processing area. The processing of the fiexible substrate can include at least one of depositing a material layer on the flexible substrate and performing an etching process. [0058] According to embodiments described herein, the method for supporting a flexible substrate on a coating drum can be conducted by means of computer programs, software, computer software products and the interrelated controllers, which can have a CPU, a memory, a user interface, and input and output means being in communication with the corresponding components of the apparatuses according to the present disclosure.

[0059] According to the present disclosure, the coating drum has a varying diameter to locally increase a tension of the substrate. As an example, the varying diameter can increase the tension of the substrate towards the substrate edges. The local increase in the tension of the flexible substrates allows for a reduction or even avoidance of heat damages of the flexible substrate. Specifically, increasing the tension at the substrate edges can prevent the substrate edges from becoming wavy or wrinkled.

[0060] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.