WO2013123997A1

WO2013123997A1 - In-situ annealing in roll to roll sputter web coater and method of operating thereof

Info

Publication number: WO2013123997A1
Application number: PCT/EP2012/053150
Authority: WO
Inventors: Hans-Georg Lotz; Armin Reus
Original assignee: Applied Materials, Inc.
Priority date: 2012-02-24
Filing date: 2012-02-24
Publication date: 2013-08-29

Abstract

An apparatus for processing a flexible substrate is described. The apparatus includes an unwinding module configured for providing the flexible substrate, a deposition module configured for depositing a layer on the flexible substrate, an annealing module having one or more heaters configured for in-situ annealing the layer, and a winding module configured for winding of the substrate with the annealed layer.

Description

IN-SITU ANNEALING IN ROLL TO ROLL SPUTTER WEB COATER AND METHOD OF OPERATING THEREOF

TECHNICAL FIELD OF THE INVENTION

[0001] Embodiments of the present disclosure relate to in-situ annealing of flexible substrates and an apparatus for processing a flexible substrate configured for in-situ annealing of the flexible substrate. Specifically, embodiments relate to manufacturing of TCO layer containing layer stacks and annealing thereof before winding of the flexible substrate.

BACKGROUND OF THE INVENTION [0002] In many applications, it is necessary to deposit thin layers on a flexible substrate. Typically, the flexible substrates are coated in one or more chambers of a flexible substrate coating apparatus. Further, a stock of a flexible substrate, for example, a roll of a flexible substrate, may be disposed in one chamber of the substrate coating apparatus. Typically, the flexible substrates are coated in a vacuum, using a vapor deposition technique, for example, physical vapor deposition or chemical vapor deposition.

[0003] Roll to roll coaters typically allow for high throughput in light of the high speed at which the flexible substrate can be guided through the deposition system. Further, the flexible substrates such as films or the like can result in lower manufacturing prices as compared to similar layer stacks deposited on a glass substrate. One example, of an application can be layer stacks for touch panels. Touch panels are a particular class of electronic visual displays, which are able to detect and locate a touch within a display area. Generally, touch panels include a transparent body disposed over a screen and configured to sense a touch. Such a body is substantially transparent, so that light in the visible spectrum emitted by the screen can be transmitted therethrough. A common manufacturing process for touch panel applications can be a sputtering process, wherein a touch panel coating is deposited on a plastic film using a roll-to-roll sputter web coater. There are several types of touch panel coatings on the market.

[0004] For some layer stacks, e.g. touch panels, the layers are deposited in a roll to roll coater. Thereafter, the roll with the deposited material is removed from the deposition system and the layer stack is annealed by being heated in an oven or the like. However, there is the desire to even further improve the CoO advantage of a manufacturer of utilizing roll to roll coaters, i.e. deposition system for flexible substrates.

SUMMARY OF THE INVENTION [0005] In light of the above, an apparatus for processing a flexible substrate according to independent claim 1 and a method of in-situ annealing a layer on a flexible substrate according to independent claim 10 are provided. Further aspects, advantages and features of the present invention are apparent from the dependent claims, the description and the accompanying drawings. [0006] According to one embodiment, an apparatus for processing a flexible substrate is provided. The apparatus includes an unwinding module configured for providing the flexible substrate, a deposition module configured for depositing a layer on the flexible substrate, an annealing module having one or more heaters configured for in-situ annealing the layer, and a winding module configured for winding of the substrate with the annealed layer.

[0007] According to another embodiment, method of in-situ annealing a layer on a flexible substrate is provided. The method includes unwinding the flexible substrate in the apparatus, depositing a layer on the flexible substrate in the apparatus and after unwinding, in-situ annealing the layer in the apparatus during or after depositing the layer, and winding the flexible substrate in the apparatus after annealing of the layer.

[0008] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method step. These method steps 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 invention are also directed at methods by which the described apparatus operates. It includes method steps for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the invention and are described in the following:

FIG. 1 shows a deposition apparatus for depositing a layer on a flexible substrate and being adapted for in-situ annealing according to embodiments described herein;

FIG. 2 shows another deposition apparatus for depositing a layer on a flexible substrate and being adapted for in-situ annealing according to embodiments described herein;

FIG. 3 shows a yet further deposition apparatus for depositing a layer on a flexible substrate and being adapted for in-situ annealing according to embodiments described herein; FIG. 4 shows an even deposition apparatus for depositing a layer on a flexible substrate and being adapted for in-situ annealing according to embodiments described herein; and

FIG. 5 shows a flow chart for illustrating a method of in-situ annealing a layer on a flexible substrate according to embodiments described herein; DETAILED DESCRIPTION OF EMBODIMENTS

[0010] Reference will now be made in detail to the various embodiments of the invention, 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 invention and is not meant as a limitation of the invention. 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.

[0011] A flexible substrate or web as used within the embodiments described herein can typically be characterized in that it is bendable. The term "flexible substrate" or "web" may be synonymously used with the term "strip". For instance, the web as described in embodiments herein may be a foil, a film, or the like. [0012] FIG. 1 illustrates an apparatus 100 for depositing one or more layers on a flexible substrate 11. Thereby, the uncoated flexible substrate can be provided on a roll 10 in the unwinding chamber 102. The flexible substrate is guided, for example through guiding rollers 20 towards the processing drum 30. One or more layers are deposited on the flexible substrate 11 while the substrate is guided through the deposition chambers or sub- chambers 40. These sub-chambers can be a portion of the deposition chamber 104. As shown in FIG. 1, the deposition sources 50 can for example be sputter targets. After depositing the one or more layers in the deposition chamber 104, the substrate 11 is further guided through guiding rollers 20 in an adjacent chamber 112. Within the adjacent chamber three heating elements 130, 132, and 134 are shown in FIG. 1. According to some embodiments, which can be combined with other embodiments described herein, one or more heating elements can be provided. The heating elements heat the substrate in the chamber 112, i.e. after deposition of the layer or the layer stack on the substrate 11. Thereby, and in-situ annealing is provided. After annealing of the coated substrate the annealed and coated substrate is provided into winding chamber 106, wherein the substrate is wound on roll 12. [0013] According to embodiments described herein, the deposition process of the layer on a flexible film, for example in a roll to roll coater, is provided, wherein a separate heating step in an oven or the like can be avoided. According to typical embodiments, which can be combined with other embodiments described herein, the deposition process can be a PVD process, for example a sputtering process. Thereby, the apparatus includes one or more sputter targets for depositing a layer or a layer stack on the substrate.

[0014] According to typical embodiments, the layer or the layer stack provided on the flexible substrate 11 can include a transparent conductive oxide layer (TCO), particularly for use in the flexible touch panel film. The flexible touch panel film can be used on touch panels, which are provided on a glass substrate or on flexible touch panel displays. Thereby, the layer or the layer stack including the TCO-coating is heated in order to provide an annealing step. The heating process being an annealing can improve the durability of the TCO-coating, lower the specific resistivity thereof, and/or can change other layer properties such as the transmittance, which can typically be increased. Since an external heating step can be omitted by introducing an in-situ heating within the deposition apparatus, the cost of ownership of the roll to roll coater can be further improved.

[0015] According to some embodiments, which can be combined with other embodiments described herein, the heating, i.e. the annealing, can be conducted at a temperature of the heating element of 150°C and above. Typically, the temperature can be 150°C to 180°C. For some types of flexible substrates, the heating can be in the range of 150°C to 250°C, for example 150°C to 210°C.

[0016] According to embodiments described herein, the apparatus 100 includes an unwinding module having an unwinding chamber 102, a deposition module having a deposition chamber 104, and annealing module, which can, for example, have an annealing chamber 112, and the winding module having the winding chamber 106. These modules and chambers are typically provided in this order.

[0017] The annealing module typically has two or more guiding rollers 20 which guide the flexible substrate 11 in a free-span guiding arrangement. At least one heater 132-134 can be provided such that the flexible substrate is guided along the heater 132-134 in a first direction and in a second direction. Thereby, the time for annealing and/or the temperature for annealing of the flexible substrate, having the coating provided thereon, can be increased. Typically, as shown in FIG. 1, three heaters 130, 132, and 134 can be provided such that the substrate is guided from the first guiding roller between the heaters 130 and 132, and the substrate is further guided between the heaters 132 and 134 between the second and the further guiding roller 20. Typically, at least one of the guiding rollers, for example guiding roller 120 shown in FIG. 1, is configured for re-directing flexible substrate by 160° to 200°, for example 180°. Thereby the length of the flexible substrate 11 provided in the annealing module can be increased.

[0018] As shown in FIG. 1, the flexible substrate 11 is guided once in a first direction and back into an essentially opposing direction. This serpentine- shaped guiding is repeated once in FIG. 1. According to different embodiments, which can be combined with other embodiments described herein, this serpentine-shaped guiding can be provided two, three, four, five or even more times.

[0019] As shown in FIG. 1, each of the chambers 102, 104, 112, and 106 include a vacuum flange 103, 105, 113, and 107, respectively. Thereby, each of the chambers are configured to be connected to a vacuum arrangement having one or more vacuum pumps. Accordingly, each of the chambers can be evacuated independently from the adjacent chamber. Therefore, according to some embodiments, which can be combined with other embodiments described herein, a sealing element can be provided between chamber 102 and chamber 104, a sealing element can be provided between chamber 104 and chamber 112, and/or a sealing element can be provided between chamber 112 and 106. Particularly, a respective sealing element can be provided between the unwinding chamber 102 and the adjacent chamber and between the winding chamber 106 and the adjacent chamber. Thereby, it is possible to exchange the roll 10 and/or roll 12 by venting the chambers 102 and 106 respectively, while maintaining a vacuum in the other chambers of the deposition apparatus 100. According to typical embodiments, the seals between the chambers can be inflatable seals or the like such that the chambers can be sealed with respect to each other while the flexible substrate 11 is provided for guidance from one chamber to the adjacent chamber. [0020] As described above, one or more deposition sources 50 are provided in the apparatus 100. Typically, these sources can be sputter targets. However, other sources like evaporators, CVD sources and PECVD sources can also be included. Thereby, particularly if a layer stack is deposited in the deposition module, i.e. within chamber 104, two or more sources can be provided, wherein the sources can individually be selected from the group consisting of: a PVD source, a sputter source, a planar or rotatable sputter source, a planar or rotatable twin-sputter source, a CVD source, a PECVD source and an evaporator. According to some embodiments, which can be combined with other embodiments described herein, one or more sputter targets can be provided in the deposition module, e.g. one sputter target per sub-chamber 40. As shown in FIG. 1, the targets can be provided as twin targets having a first deposition surface 52 and a second deposition surface 54.

[0021] The term "twin target" refers to a pair of two targets, wherein the two targets are combined to a twin-target. A first target portion 52 and a second target portion 54 may form a twin target pair. For instance, both targets of the twin target pair may be simultaneously used in the same deposition process to coat the same substrate. Twin targets can be used to coat the same section of a substrate at the same time. According to some embodiments, which can be combined with other embodiments described herein, the two targets of a twin target include the same deposition material. According to some embodiments, the deposition apparatuses and the arrangements described above may be used such that the twin-targets are operated under middle frequency (MF). According to embodiments herein, middle frequency is a frequency in the range of 5 kHz to 100 kHz, for example, 10 kHz to 50 kHz. Sputtering from a target for a transparent conductive oxide film is typically conducted as DC sputtering. In one embodiment, the deposition apparatus and/or the target supports of the deposition apparatuses may be adapted for using one of the targets as an anode and the respective other one as a cathode. Generally, the deposition apparatus is adapted so that the operation of the targets as anode and cathode may be alternated. That means that the target portions 52 and 54 being formerly used as an anode may be used as a cathode, and the target being formerly used as a cathode may be operated as an anode.

[0022] According to embodiments described exemplarily with respect to FIG. 1, a processing drum 30 is provided. Commonly, the processing drum 30 can be utilized to cool the flexible substrate 11 during deposition, e.g. for receiving heat generated during deposition and/or the processing drum can be provided at a temperature for best deposition characteristics of the layer or layer stack to be deposited. Accordingly, the flexible substrate 11 is guided over the processing drum while the substrate is guided past the deposition sources 50. [0023] According to further embodiments, which can be combined with other embodiments described herein to the extent they are not inconsistent with each other, a free-span deposition apparatus 200 may also be provided. Therein, the flexible substrate 11 is guided from roll 10, optionally via further guiding rollers (not shown), in such a manner that the substrate passes deposition sources 50 without having contact to a roll, a drum, or a roller. Thereby, as shown in FIG. 2, a heater 60 can be provided for heating the substrate during deposition. Typically, the deposition heater 60 is provided on the opposing side of the flexible substrate 11 as compared to the deposition sources 50.

[0024] The apparatus 200 for depositing one or more layers on a flexible substrate 11, as shown in FIG. 2 similarly to the apparatus 100 shown in FIG. 1, is configured such that an uncoated flexible substrate can be provided on a roll 10 in the unwinding chamber 102. The flexible substrate is guided past the deposition sources 50. One or more layers are deposited on the flexible substrate 11 while the substrate is guided through the deposition chamber 204. The deposition sources 50 can for example be sputter targets. After depositing the one or more layers in the deposition chamber 204, the substrate 11 is further guided through guiding rollers 20 in an adjacent chamber 112. Within the adjacent chamber three heating elements 130, 132, and 134 are shown in FIG. 2. According to some embodiments, which can be combined with other embodiments described herein, one or more heating elements can be provided. The heating elements heat the substrate in the chamber 112, i.e. after deposition of the layer or the layer stack on the substrate 11. Thereby, an in-situ annealing is provided. After annealing of the coated substrate, the annealed and coated substrate is provided into winding chamber 106, wherein the substrate is wound on roll 12.

[0025] According to typical embodiments, the layer or the layer stack provided on the flexible substrate 11 can include a transparent conductive oxide layer (TCO), particularly for use in the flexible touch panel film. The flexible touch panel film can be used on touch panels, which are provided on a glass substrate or on flexible touch panel displays. [0026] According to some embodiments, which can be combined with other embodiments described herein, the TCO layer can be an ITO layer, which is sputtered on the flexible substrate 11. A layer stack for touch panel applications can further include one or more dielectric layers selected from the group consisting of: SiOx, SiOxNy, AlOx, AlOxNy, TiOx and NbOx. The layer or the layer stack including the TCO-coating, e.g. Π , is heated in order to provide an annealing step. The heating process can improve the durability of the TCO-coating and/or lower the specific resistivity thereof.

[0027] According to some embodiments, which can be combined with other embodiments described herein, the heating, i.e. the annealing, can be conducted at a temperature of the heating element of 150°C and above. Typically, the temperature can be 150°C to 180°C. For some types of flexible substrates, the heating can be in the range of 150°C to 250°C, for example 150°C to 210°C.

[0028] For the specific example of ITO-TCO layers, particularly for touch panel applications, it has been found that the annealing changes the properties of the ITO layer. The ΓΤΟ layer partly crystallizes during the annealing process. This improves the durability and other properties of the layer. For example a reduced optical absorption and an increased transmittance can be provided by annealing. It has been shown that in-situ annealing on heated coated drum (see, e.g. FIG. 1) in a range of 160°C to 200°C, e.g. 180°C, showed that the ITO film on a PEN substrate was partly converted to the crystallized state. Typically, annealing is referred to as a heating step, wherein the initial layer properties after or during growth of the layer are modified by the heating, i.e. the annealing.

[0029] According to embodiments described herein, the apparatus 200 includes an unwinding module having an unwinding chamber 102, a deposition module having a deposition chamber 104, and an annealing module which can, for example, have an annealing chamber 112, and the winding module having the winding chamber 106. These modules and chambers are typically provided in this order.

[0030] The annealing module typically has two or more guiding rollers 20 which guide the flexible substrate 11 in a free-span guiding arrangement. The annealing module shown in FIG. 2 can be similar to embodiments of annealing modules as described above with respect to FIG. 1.

[0031] As shown in FIG. 2, each of the chambers 102, 104, 112, and 106 includes a vacuum flange 103, 105, 113, and 107, respectively. Thereby, each of the chambers is configured to be connected to a vacuum arrangement having one or more vacuum pumps, as described above with respect to FIG. 1

[0032] The one or more deposition sources 50, which are provided in the apparatus 200 can be sputter targets. However, other sources like evaporators, CVD sources, PECVD sources can also be included. Thereby, particularly if a layer stack is deposited in the deposition module, i.e. within chamber 104, two or more sources can be provided, wherein the sources can individually be selected from the group consisting of: a PVD source, a sputter source, a CVD source, a PECVD source and an evaporator.

[0033] According to typical embodiments, which can be combined with other embodiments described herein, one of the targets can be an ITO target, whereas other targets can be selected from a target including Nb, Ti , Si, or the like. Layers forming oxides or nitrides of an element can either be deposited by a reactive sputtering process, wherein a reactive process gas is provided in the sputter region to form an oxide, a nitride, or an oxinitride of the material to be deposited. Alternatively, the deposition material can in some cases also be provided as an oxide, a nitride or an oxinitride. [0034] According to different embodiments, which can be combined with other embodiments described herein, the annealing of the flexible substrate and the layer deposited thereon can, for example, be conducted by heating of the coated substrate after the film has left the coating drum and/or a deposition free-span area. The film can be heated a separate vacuum zone, see chambers 112 in FIGS 1 and 2. For example, thermal heaters, such as IR lamps or other heat radiators, or alternative heating methods such as electron bombardment or microwave heating can be used. Thereby, the apparatus includes an annealing station, which is positioned such that the substrate is annealed before it is wound on the roll 12 in the winding chamber 106. [0035] According to other embodiments, which can be combined with other embodiments described herein, the heating of the coated layer to anneal the coated layer can be realized by using a coating drum (see, e.g. FIG. 1), which can be heated to the required annealing temperature. The heating, i.e. the annealing, can be conducted at a temperature of the coating drum of 150°C and above. Typically, the temperature can be 150°C to 180°C. For some types of flexible substrates, the heating can be in the range of 150°C to 250°C, for example 150°C to 210°C.

[0036] For embodiments, where the coating is conducted in a free span zone (see, e.g. FIG. 2) the substrate can be heated from the rear side by heating element 60. The heating, i.e. the annealing, can be conducted at a temperature of the heater 60 of 150°C and above. Typically, the temperature can be 150°C to 180°C. For some types of flexible substrates, the heating can be in the range of 150°C to 250°C, for example 150°C to 210°C.

[0037] According to typical embodiments, which can be combined with other embodiments described herein, the annealing in the deposition chamber can be conducted by heating the respective element to a temperature, which is about 30°C to about 150 °C higher than the temperature during deposition without annealing. For example, typical temperatures during deposition are below 80°C, e.g. the processing drum is controlled to be at a temperature below 80°C. If an annealing is conducted during deposition, the temperature of the respective element is increased. [0038] Particularly for embodiments, with heating elements 60 as shown in FIG. 2, the annealing can be conducted by providing a temperature ramp. Thereby, the heater 60 shown in FIG. 2 can be provided in two or more segments, which are configured for allowing different temperatures. Thereby, it is possible to provide a first segment of the heater, e.g. a rear side heater, at a temperature suitable for nucleation of the layer to be deposited. That is, while the first seeds and/or the first portion of the layer is deposited, a first temperature is provided. The first temperature is optimized for good deposition quality. A further segment or further segments provide a second temperature (or second and further temperatures), which are higher than the first temperature. Accordingly, a first portion of the layer, which has been deposited at the first temperature can be annealed at the second temperature, while the deposition process is still continuing. Thereby, nucleation, which can be critical for the entire deposition process, benefits from the first temperature while the second temperature already provides modification of the properties of the portion of the layer as compared to the properties of the layer portion grown at the first temperature. These annealing temperatures allow for in-situ annealing in the deposition chamber of the deposition apparatus. A further portion of the layer can, then be annealed in a post anneal module or station before winding of the flexible substrate. Thereby, the length of the post annealing module can be reduced.

[0039] The embodiments described herein, can be particularly useful for in-situ annealing in touch panel applications. The deposited ITO layers of touch panels on flexible substrates are often annealed outside the coating machine in an oven. The herein-described in-situ annealing allows for more effective substrate processing by in-situ annealing, which allows for omitting the external oven.

[0040] Another embodiment of a deposition apparatus 100 for deposition and for in-situ annealing is shown in FIG. 3. Fig. 3 shows an unwinding module having an unwinding chamber with a roll to be provided therein. The substrate 11 is guided over guiding rollers 20 to processing drum 30 in deposition chamber 104. Within the deposition chamber 104 there are sub-chambers 40 or respective areas, wherein the substrate can be processed while being guided over the coating drum.

[0041] According to different embodiments, which can be combined with other embodiments described herein, Fig. 3 also illustrates deposition sources, which can additionally or alternatively be used. Exemplarily, FIG. 3 shows a rotatable sputter target 350 and a rotatable twin target having rotatable targets 352 and 354. The rotatable targets can be rotated during sputtering in order to provide improved material usage as compared to planar targets. The rotatable twin-targets can also be provided as an alternating cathode- anode- arrangement as described for the planar twin-targets above. For example, middle frequency high power can be provided for sputtering from these targets. According to embodiments herein, middle frequency is a frequency in the range of 5 kHz to 100 kHz, for example, 10 kHz to 50 kHz.

[0042] In addition or alternatively to the annealing utilizing the coating drum 30 as described above, the latter two of the sub-chambers 40 or respective areas of the deposition chamber 104 are equipped with heaters 322, such as radiation heaters or the like. Accordingly, embodiments can also provide, additionally or alternatively, one ore more heating elements being front-side heating elements in the deposition chamber 104. As compared to the rear-side heater 60 shown in FIG. 2, the front-side is considered as the side onto which the layer is deposited. [0043] FIG. 4 shows a yet further apparatus 100 for processing a flexible substrate. Therein, heaters 322 for annealing in a deposition region of the deposition chamber 104, heaters 422 for annealing in a post-deposition region of the deposition chamber 104 and heaters in an annealing chamber 112 are provided. According to different embodiments, which can be combined with other embodiments described herein, one, two or three of these types of heaters can be provided in the apparatuses described herein. For example, thermal heaters, such as IR lamps or other heat radiators, or alternative heating methods such as electron bombardment can be used for heaters 322, heaters 422, and/or heaters 130, 132, 134.

[0044] The apparatus 100 for depositing one or more layers on a flexible substrate 11, as shown in FIG. 4 similarly to the apparatus 100 shown in FIG. 1, is configured such that an uncoated flexible substrate can be provided on a roll 10 in the unwinding chamber 102. The flexible substrate is guided past the deposition sources 450 and 50, respectively. One or more layers are deposited on the flexible substrate 11 while the substrate is guided through the deposition chamber 104. [0045] As shown in FIG. 4, the deposition sources can be a planar sputter source 450 or a planar twin-target. Likewise, rotatable sources as described with respect to FIG. 3 or other sources (other than sputter sources) can also be provided. For example, the sources can individually be selected from the group consisting of: a PVD source, a sputter source, a planar sputter sources, a rotatable sputter sources, a CVD source, a PECVD source and an evaporator. According to typical embodiments, which can be combined with other embodiments described herein, one of the targets can be an ITO target, whereas other targets can be selected from Nb, Ti, Si, or the like. Layers forming oxides or nitrides of an element can either be deposited by a reactive sputtering process, wherein a reactive process gas is provided in the sputter region to form an oxide, a nitride, or an oxinitride of the material to be deposited. Alternatively, the deposition material can in some cases also be provided as an oxide, a nitride, or an oxinitride. [0046] After depositing the one or more layers in the deposition chamber 204, the substrate 11 is further guided past the heaters 322 and 422 before being guided by guiding rollers 20 in an adjacent chamber 112. Within the adjacent chamber are three heating elements 130, 132, and 134, as shown in FIG. 4. According to some embodiments, which can be combined with other embodiments described herein, one or more heating elements can be provided. The heating elements heat the substrate in the chamber 104 and/or 112, i.e. after deposition of the layer or the layer stack on the substrate 11. As described above, deposition heating elements can alternatively or additionally be used for annealing during deposition of the layer or the stack of layers. Thereby, and in-situ annealing is provided. After annealing of the coated substrate the annealed and coated substrate is provided into winding chamber 106, wherein the substrate is wound on roll 12. The annealing chamber 112 typically has two or more guiding rollers 20 which guide the flexible substrate 11 in a free-span guiding arrangement. The annealing chamber 112 shown in FIG. 4 can be similar to embodiments of the annealing chamber as described above with respect to FIG. 1. [0047] According to typical embodiments, the layer or the layer stack provided on the flexible substrate 11 can include a transparent conductive oxide layer (TCO), particularly for use in the flexible touch panel film. The flexible touch panel film can be used on touch panels, which are provided on a glass substrate or on flexible touch panel displays. For the specific example of ITO-TCO layers, particularly for touch panel applications, it has been found that the annealing changes the properties of the ITO layer. The ITO layer partly crystallizes during the annealing process. This improves the durability and other properties of the layer.

[0048] As shown in FIG. 4, each of the chambers 102, 104, 112, and 106 includes a vacuum flange 103, 105, 113, and 107, respectively. Thereby, each of the chambers is configured to be connected to a vacuum arrangement having one or more vacuum pumps. As described above with respect to FIG. 1. FIG. 4 further shows a portion 404 of the chamber 104, which is provided as a gas separation portion. A gas separation element 412 is provided as well as, optionally a further vacuum flange 405. The gas separation device provides a gap between the gas separation device and the processing drum 30 for passing the substrate therethrough. The gap provides an increase flow resistance for processing gases from one end of the gas separation device to the other end of the gas separation device. The vacuum flange can be used to further evacuate the area around the gas separation device to avoid having processing gases from one side entering the other side.

[0049] A method of in-situ annealing a layer on a flexible substrate is shown in FIG. 5. In step 502 the flexible substrate is unwound, e.g. from a roll in an unwinding module. Thereafter, in step 504 a layer or a stack of layers is deposited on the flexible substrate in the apparatus. After or during the deposition the coated layer is annealed in step 506, e.g. by providing heating elements selected from the group consisting of a processing drum in the deposition chamber, a rear-side heatining element in the deposition chamber, a front-side heating element in a region suitable for deposition in the deposition chamber, a front-side heating element outside a region suitable for deposition in the deposition chamber, and a heating element in an annealing chamber. Thereby, a region outside the region suitable for deposition in the deposition chamber, the annealing chamber, and/or a portion of the winding chamber can be provided as the annealing module. Thereafter, in step 508, the flexible substrate is wound on a roll after annealing of the layer.

[0050] In light of the above, a plurality of embodiments has been described. According to one embodiment, an apparatus for processing a flexible substrate is provided. The apparatus includes an unwinding module configured for providing the flexible substrate, a deposition module configured for depositing a layer on the flexible substrate, an annealing module having one or more heaters configured for in-situ annealing the layer, and a winding module configured for winding the substrate with the annealed layer, wherein the annealing module is provided between the deposition module and the winding module. Yet further embodiments, can be yielded by combination of the details, features, aspects described in the other embodiments, the dependent claims and the drawings, wherein the details, features and aspects can be provided as alternatives or in addition to each other to the extent they are not inconsistent with each other.

[0051] The embodiments described herein, can be utilized to omit or reduce the need for external annealing in an oven being provided outside of the substrate processing apparatus, i.e. layer deposition apparatus. Replacing the annealing step in an oven by in-situ annealing saves time and costs for the owner of a roll to roll coater, such that the CoO will be improved. [0052] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. An apparatus for processing a flexible substrate, comprising: an unwinding module configured for providing the flexible substrate; a deposition module configured for depositing a layer on the flexible substrate; an annealing module having one or more heaters configured for in- situ annealing the layer; and a winding module configured for winding of the substrate with the annealed layer.

2. The apparatus according to claim 1, wherein the annealing module comprises: two or more guiding rollers configured for guiding the flexible substrate in a first free-span guiding arrangement and at least one heater of the one or more heaters is provided between a first guiding roller and a second guiding roller of the two or more guiding rollers.

3. The apparatus according to claim 2, wherein at least one guiding roller of the first guiding roller and the second guiding roller is configured for re-directing the flexible substrate by 160° to 200°.

4. The apparatus according to claim 3, wherein the at least one heater is positioned to heat the substrate before and after the re-directing of the flexible substrate.

5. The apparatus according to claim 4, further comprising: at least a third guiding roller of the two or more guiding rollers to provide a second free- span arrangement for the flexible substrate, wherein the one or more heaters are at least three heaters, wherein the substrate is guided between two of the at least three heaters in the first free-span arrangement, and wherein the substrate is guided between two of the at least three heaters in the second free-span arrangement.

6. The apparatus according to any of claims 1 to 5, wherein at least two modules of the unwinding module, the deposition module, the annealing module and the winding module are each provided in a sealable vacuum chamber, particularly wherein the unwinding module, the deposition module, the annealing module, and the winding module are each provided in a sealable vacuum chamber.

7. The apparatus according to any of claims 1 to 6, wherein the unwinding module and the winding module each comprises a roller for winding or unwinding the flexible substrate, respectively.

8. The apparatus according to any of claims 1 to 7, wherein the depositing module comprises a source configured for deposition of a TCO layer, particularly an ITO layer.

9. The apparatus according to any of claims 1 to 8, wherein the depositing module further comprises a heatable processing drum configured for heating the substrate during deposition or a deposition heater for heating the substrate in a deposition free-span arrangement configured for heating the substrate during deposition, particularly wherein the deposition heater is position on a substrate side opposing the deposition side of the substrate.

10. A method of in-situ annealing a layer on a flexible substrate in an apparatus, comprising: unwinding the flexible substrate in the apparatus; depositing a layer on the flexible substrate in the apparatus and after unwinding; in-situ annealing the layer in the apparatus during or after depositing the layer; and winding the flexible substrate in the apparatus after annealing of the layer.

11. The method of claim 10, wherein the layer is a TCO layer and particularly an ITO layer.

12. The method of any of claims 10 to 11, wherein the annealing comprises heating elements, which are configured for heating the substrate, to a temperature of 150°C to 250°C, particularly 150°C to 210°C.