WO2019166103A1

WO2019166103A1 - Method for forming a coating on a substrate in a vacuum processing chamber, vacuum processing chamber and vacuum processing system

Info

Publication number: WO2019166103A1
Application number: PCT/EP2018/055188
Authority: WO
Inventors: Elisabeth Sommer; Peter Olbrich
Original assignee: Applied Materials, Inc.
Priority date: 2018-03-02
Filing date: 2018-03-02
Publication date: 2019-09-06

Abstract

According to one aspect of the present disclosure, a method for forming a coating on a substrate (10) in a vacuum processing chamber (100) is provided. The method includes: forming a liquid film (110) on the substrate (10) by spraying a liquid (L) on the substrate (10), wherein the coating is formed to a thickness of less than 1 µm.

Description

METHOD FOR FORMING A COATING ON A SUBSTRATE IN A VACUUM PROCESSING CHAMBER, VACUUM PROCESSING CHAMBER AND

VACUUM PROCESSING SYSTEM

TECHNICAE FIEED

[0001] Embodiments of the present disclosure relate to methods for forming a coating on a substrate in a vacuum processing chamber, vacuum processing chambers and vacuum processing systems. Embodiments of the present disclosure particularly relate to methods for forming a coating on a substrate in a vacuum processing chamber by spraying a liquid on the substrate. Embodiments also particularly relate to vacuum processing chambers having a nozzle arrangement configured for spraying fine liquid droplets on a substrate.

BACKGROUND

[0002] Substrates, e.g. flexible substrates, are regularly processed while being moved past processing equipment. Processing may include coating of a flexible substrate with a coating material, e.g. metal, particularly aluminum or copper, semiconductors or dielectric materials. Systems performing this task may include a coating drum coupled to a transport system for moving the substrate along a substrate transportation path, wherein at least a portion of the substrate is processed while the substrate is guided on the coating drum. So- called roll-to-roll (R2R-) coating systems, allowing substrates to be coated while being moved on the guiding surface of a coating drum, can provide a high throughput. [0003] An evaporation process, such as a thermal evaporation process, a PVD (physical vapor deposition) process and/or a CVD (chemical vapor deposition) process can be utilized for depositing thin layers of coating material on the flexible substrate. Roll-to-roll deposition systems are also experiencing a strong increase in demand in the display industry, the photovoltaic (PV) industry the, e.g. lithium, battery industry, and flexible barrier packaging applications. For example, touch panel elements, flexible displays, and flexible PV modules result in an increasing demand for depositing suitable layers in roll- to-roll coaters with low manufacturing costs. Such devices are typically manufactured with several layers of coating material, which may be produced in roll-to-roll coating apparatuses which successively utilize several deposition units. The deposition units may be adapted for coating the substrate with a particular coating material while the substrate is moved past the deposition units by a transport system, e.g. a roller assembly.

[0004] In some applications, substrates, e.g. flexible substrates, such as foils, or inflexible substrates, such as glass plates, are passivated for further processing, e.g. inside or outside a vacuum processing system. The passivation is usually performed under a certain elevated temperature which may deteriorate the layers coated on the substrate. Furthermore freshly coated layers may be deteriorated if not protected, e.g. during contact with guide rollers.

[0005] There remains a need for methods for forming a coating on a substrate in a vacuum processing chamber and vacuum processing chambers that overcome at least some of the problems in the art. The present disclosure aims to provide a method for forming a coating on a substrate in a vacuum processing chamber which can be performed at ambient temperature.

SUMMARY

[0006] In light of the above, a method for forming a coating on a substrate in a vacuum processing chamber and vacuum processing chambers are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0007] According to one aspect of the present disclosure, a method for forming a coating on a substrate in a vacuum processing chamber is provided. The method includes: forming a thin film on the substrate by spraying the liquid on the substrate. The coating is formed to a thickness of less than 1 pm. Specifically, the liquid can be sprayed on the substrate as fine liquid droplets, e.g. by use of a nozzle arrangement that can transfer the liquid into the fine liquid droplets.

[0008] According to a further aspect of the present disclosure, a vacuum processing chamber for forming a coating on a substrate is provided. The vacuum processing chamber includes: a nozzle arrangement configured for forming a liquid film on the substrate by spraying a liquid on the substrate. The coating to be formed has a thickness of less than 1 pm.

[0011] Further aspects, advantages, and features of the present disclosure are apparent from the dependent claims, the description, and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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. Typical embodiments are depicted in the drawings and are detailed in the description which follows.

[0013] FIG. 1 shows a schematic side view of a vacuum processing chamber according to embodiments described herein;

[0014] FIGs. 2A, 2B and 2C show schematic side views of vacuum processing chambers according to embodiments described herein;

[0015] FIG. 3 shows a schematic sectional view of a vacuum processing chamber according to embodiments described herein;

[0016] FIG. 4 shows a schematic side view of a vacuum processing chamber according to embodiments described herein; and

[0017] FIG. 5 shows a flow diagram of a method for forming a coating on a substrate in a vacuum processing chamber according to embodiments described herein.

DETAILED DESCRIPTION

[0018] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in the figures. The examples are provided by way of explanation and are not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield a further embodiment. Intension is that the present disclosure includes such modifications and variations.

[0019] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Specifically, the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0020] According to embodiments described herein, a vacuum processing chamber is provided. The vacuum processing chamber can be included in a processing system for processing a substrate, specifically a flexible substrate. The processing system can include the vacuum processing chamber according to embodiments described herein. The processing system can be configured to coat the substrate with one or more layers, e.g. metal layers, dielectric layers, and/or semiconductor layers in the vacuum processing chamber. Specifically,“processing” can be understood or can include depositing a film on a substrate, e.g. by PVD processes such as sputtering, or CVD processes, winding a substrate by use of roller assembly, transporting a substrate through a vacuum processing chamber etc.

[0021] The term substrate as used herein shall particularly embrace flexible substrates such as a plastic film, a web, a foil, flexible glass or a strip. The term substrate shall also embrace other types of flexible substrates. A flexible substrate as used within the embodiments described herein can be bendable. The term “flexible substrate” or “substrate” may be synonymously used with the term“foil” or the term“web”. In particular, some embodiments of the processing system described herein can be utilized for coating any kind of flexible substrate, e.g. for manufacturing flat coatings with a uniform thickness, or for manufacturing coating patterns or coating structures in a predetermined shape on the flexible substrate or on top of an underlying coating structure. For example, electronic devices may be formed on the flexible substrate by masking, etching and/or depositing. For example, a flexible substrate as described herein may include materials like PET, HC-PET, PE, PI, PUR, OPP, CPP, GLASS, one or more metals, paper, PLA, biopolymers, combinations thereof, and coated substrates like Hard Coated PET (e.g. HC-PET) and the like. In some embodiments, the flexible substrate is a COP substrate provided with an index matched (IM) layer on both sides thereof.

[0022] A substrate may be moved while being processed in the vacuum processing chamber. For example, the substrate may be transported along a substrate transportation path P past deposition units for coating the flexible substrate. In some implementations, the substrate, specifically a flexible substrate, may be unwound from a storage roller, may be transported on the outer surface of a coating drum, and may be guided along the outer surfaces of further rollers. The coated flexible substrate may be wound onto a wind-up spool.

[0023] According to some embodiments, which can be combined with other embodiments described herein, the processing system may be configured for processing a substrate with a length of 500 m or more, 1000 m or more, or several kilometres. The substrate width can be 100 mm or more, 300 mm or more 500 mm or more, or 1 m or more. The substrate width can be 5 m or less, particularly 2 m or less. Typically, the substrate thickness can be 20 pm or more and 1 mm or less, particularly from 50 pm to 200 pm.

[0024] Furthermore, in the following description, a roller or roller device, e.g. as part of a roller assembly, may be understood as a device, which provides a surface, with which a substrate (or a part of a substrate) may be in contact during the presence of the substrate in a deposition arrangement (such as a deposition apparatus or deposition chamber). At least a part of the roller device may include a circular-like shape for contacting the substrate. In some embodiments, the roller device may have a substantially cylindrical shape. The substantially cylindrical shape may be formed about a straight longitudinal axis or may be formed about a bent longitudinal axis. According to some embodiments, the roller device as described herein may be adapted for being in contact with the flexible substrate. The roller device as referred to herein may be a guiding roller adapted to guide a substrate while the substrate is coated (or a portion of the substrate is coated) or while the substrate is present in a processing apparatus, a spreader roller adapted for providing a defined tension for the substrate to be coated, a deflecting roller for deflecting the substrate according to a defined travelling path or the like. [0025] FIG. 1 shows a schematic side view of a vacuum processing chamber 100 according to embodiments described herein. The vacuum processing chamber 100 can be configured for providing a vacuum during processing of a substrate 10 in the vacuum processing chamber 100.

[0026] The vacuum processing chamber 100 includes a nozzle arrangement 150 configured for forming a liquid film 110 on the substrate 10 by spraying a liquid L on the substrate 10. In the context of the present disclosure“liquid”, such as the liquid L, can be understood as a nearly incompressible fluid that can conform to a shape of a container but retains a (nearly) constant volume independent of pressure. As such, liquid can be considered as one of the four fundamental states of matter (the others being solid, gas, and plasma), and is a state with a definite volume but no fixed shape. Accordingly“liquid” as used in the context of the present disclosure, can be particularly distinguished from gas. Further,“liquid film”, such as the liquid film 110, can be understood as a film made of a “liquid”. That is, a“liquid film” can be liquid and particularly distinguished from a gaseous film or a solid film.

[0027] Specifically, the nozzle arrangement 150 can be configured for forming an aerosol A by atomizing a liquid L and spraying the aerosol A on the substrate 10. In the context of the present disclosure, an“aerosol”, such as the aerosol A, can be understood as a liquid, specifically as a colloid of fine liquid droplets that may be dissolves in a gaseous medium. The liquid droplets or particles can have a diameter mostly smaller than 1 pm or so.

Accordingly, an“aerosol” can be understood as liquid droplets being dissolved in a gaseous medium, such as processing gases used during vacuum processing or carrying gases used in spraying the liquid L, in vacuum.

[0028] For instance, an“aerosol” can be formed by atomizing a liquid. In this context, “atomizing” can be understood as transferring a liquid into an aerosol. For instance,

“atomizing a liquid” can be understood as“producing (fine) liquid droplets from a liquid”. Accordingly, the sprayed liquid L and/or an“aerosol” can be particularly delimited from a vapour or steam. For forming a vapour or steam, a liquid is transitioned into the gaseous phase and hence includes a gaseous phase of the liquid. According to embodiments described herein, the liquid is not or mainly not transitioned into the gaseous phase by atomizing the liquid.

[0029] An “aerosol”, such as the aerosol A, can be beneficially formed at low temperatures, such as an ambient temperature or room temperature. Whereas a vapour or steam is normally formed under elevated temperatures to transition the liquid from the liquid phase to the gaseous phase. Accordingly, the temperature at which the“aerosol” is formed can be another factor to delimit an“aerosol” from a vapour or steam.

[0030] According to embodiments described herein, the liquid film 110 can be formed on the substrate 10 in the vacuum processing chamber by atomizing a liquid L for forming an aerosol A and spraying the aerosol A on the substrate 10.

[0031] As outlined, the liquid film and/or coating can be formed at lower temperatures as compared to an evaporation process. Hence, the coating can be formed at temperatures low enough to avoid a deterioration of a functional layer or layer system that has been formed on the substrate 10 already. When practicing embodiments, a reaction with an underlying functional layer or layer system can be minimized.

[0032] Further, when practicing embodiments, contamination of the vacuum processing chamber can be minimized and/or lifetime of the vacuum processing chamber can be increased. Contrarily, if the protective material would be deposited from the vapour phase the material would condense on, particularly cold, parts of the vacuum processing chamber and even jam the vacuum pumping system. Accordingly, maintenance can be reduced when practicing embodiments.

[0033] The vacuum processing chamber 100 can further include a transport system (not shown) configured to guide the substrate 10, specifically the flexible substrate 10, through the vacuum processing chamber 100 along a substrate transportation path P.

[0034] For example, the nozzle arrangement 150 can be used for the production of a protective coating and/or a barrier layer on the substrate 10. Coating the flexible substrate with one or more barrier layers or protective coatings may reduce the permeation rates for gases such as oxygen, carbon dioxide and water vapor. Thus, the shelf life of products packed into the barrier layers or protective coatings can be increased, and the quality of the packed product can be maintained over a longer period of time. The barrier properties of the barrier layers and/or the protective properties of the protective coatings can depend on the type and thickness of the substrate 10 as well as on the type and thickness of the barrier layer(s) and/or protective coating(s) deposited thereon.

[0035] According to embodiments described herein, the liquid L can include a liquid polymer composition. Specifically, the liquid can include polymer strains which are not interconnected. For instance, the liquid L can include a polymer composition containing Mono- , Di- und Triacrylate and other components like Acid Ester.

[0036] According to embodiments described herein, the liquid (L) has a low vapor pressure p_vap. In the context of the present disclosure,“vapor pressure” or“equilibrium vapor pressure”, such as the vapor pressure p_vap, can be understood as the pressure exerted by a vapor in thermodynamic equilibrium at a given pressure and temperature in a closed system. The equilibrium vapor pressure can be an indication of a liquid's evaporation rate. The equilibrium vapor can relate to the tendency of particles to escape from the liquid. A substance with a high vapor pressure at normal or ambient temperatures is often referred to as volatile. The pressure exhibited by vapor present above a liquid surface may be known as vapor pressure. As the temperature of a liquid increases, the kinetic energy of the molecules also increases. As the kinetic energy of the molecules increases, the number of molecules transitioning into a vapor also increases, hence increasing the vapor pressure. For instance, the vapor pressure p_vap can be measured and/or determined by an effusion method using a Knudsen Cell.

[0037] The liquid L can have a low vapor pressure p_vap. For instance, the vapor pressure p_vap of the liquid at room temperature RT can be equal to or smaller than 1E-1 mbar, specifically equal to or smaller than 1E-3 mbar, particularly equal to or smaller than 1E-4 mbar, further specifically equal to or smaller than 1E-5 mbar. As the liquid F can have the low vapor pressure p_vap, the liquid F tends not to transition into the gaseous phase and/or to remain in the liquid phase. This effect can even be increased by lower temperatures applied during the formation of the liquid film.

[0038] According to embodiments described herein, the liquid F can be atomized and/or sprayed in vacuum at a temperature T below or significantly below an evaporation temperature T_evap of the liquid L. Specifically, the liquid L can be atomized and/or sprayed at ambient temperature or room temperature. In the context of the present disclosure, an“evaporation temperature”, such as the evaporation temperature T_eVap, can be understood as a temperature, specifically a temperature elevated by heating, at which the liquid will turn into vapor.

[0039] According to embodiments, the liquid L can have low surface tension. Specifically, the liquid L can have a surface tension so that a surface energy of the substrate 10 is higher than a surface energy of the liquid L or the liquid film 110. When practicing embodiments, the surface of the substrate can be wetted completely and/or a homogeneous and/or thin liquid film and/or coating can be formed. Specifically, the surface homogeneity can be increased in practice.

[0040] According to embodiments described herein, the nozzle arrangement 150 can be configured for altering a particle size of the liquid L and/or the aerosol A. Specifically, the nozzle arrangement 150 can be configured to alter a size of the liquid droplets or particles. For instance, the nozzle arrangement 150 can be configured to atomize the liquid L into smaller or larger particles depending on the liquid L used and/or an intended thickness of the coating to be formed. According to embodiments described herein, the nozzle arrangement 150 can be configured for altering the particle size of the liquid droplets to a particle size of equal to or smaller than 10 pm, specifically equal to or smaller than 5 pm, particularly equal to or smaller than 3 pm. According to embodiments described herein, the nozzle arrangement 150 can be configured for altering the particle size of the liquid droplets to a particle size of equal to or smaller than 1 pm, specifically equal to or smaller than 0.5 pm, particularly equal to or smaller than 0.1 pm. When practicing embodiments, thin coatings with high homogeneity can be formed.

[0041] Without being wished to be bound by theory, the liquid droplets may disperse on the substrate 10, in particular on the surface of the substrate 10. Accordingly, the thickness of the coating may be smaller than a particle size of the liquid droplets. According to embodiments described herein, the surface may have low surface tension. Alternatively or additionally, the surface can be coated with a preparation layer having a modified surface tension and or energy. For instance, the preparation layer can have a lower or greater surface tension as the substrate 10. According to embodiments described herein, the preparation layer can modify a surface tension with respect to the surface of the substrate 10.

[0042] According to embodiments, the nozzle arrangement 150 can include a plurality of nozzles 151, 152, 153. The nozzles 151, 152, 153 can be mechanical nozzles, injection valves, ultrasonic nozzles and/or combinations thereof. According to embodiments, the nozzles 151, 152, 153 can be configured for altering a particle size of the droplets.

[0043] Specifically, the plurality of nozzles 151, 152, 153 can be arranged parallel to a transverse direction TD of the substrate 10. The transverse direction TD can be within or parallel to a plane of the substrate 10 and/or perpendicular to a direction of the substrate transportation path P. The nozzle arrangement 150 can be configured to form the coating along a lateral dimension, specifically a total lateral dimension, of the substrate 10 in the transverse direction TD. Specifically, the plurality of nozzles 151, 152, 153 can be arranged so as to form the coating along the lateral dimension, specifically the total lateral dimension, of the substrate 10 in the transverse direction TD. Additionally or alternatively, masking arrangements (not shown) may be provided that cover some areas of the substrate 10 and/or avoid coating of some areas of the substrate 10.

[0044] Further, the plurality of nozzles 151, 152, 153 can be arranged with a displacement in a direction perpendicular to the transverse direction TD. For instance, the plurality of nozzles 151, 152, 153 can be arranged with a displacement in the direction of the substrate transportation path P. Specifically, the plurality of nozzles 151, 152, 153 can be arranged with an alternating displacement, a gradual displacement and/or combinations thereof.

[0045] Furthermore, the plurality of nozzles 151, 152, 153 can be moveable in the transverse direction TD and/or the direction of the substrate transportation path P. Beneficial, the plurality of nozzles 151, 152, 153 can be moveable in the transverse direction TD. When practicing embodiments, the surface homogeneity can be optimized.

[0046] The nozzles of the plurality of nozzles 151, 152, 153 can be arranged with a distance d or gap d between adjacent nozzles. The distance d can be the same for all nozzles of the plurality of nozzles 151, 152, 153 and or vary from nozzle to nozzle. For instance, the distance g can be equal to or greater than 20 cm, specifically equal to or greater than 10 cm, particularly equal to or greater than 5 cm and/or equal to or smaller than 5 cm, specifically equal to or smaller than 1 cm, particularly equal to or smaller than 0.5 cm.

[0047] The nozzle arrangement 150, specifically the nozzles of the plurality of nozzles

151, 152, 153, can be configured to spray the liquid L under a spraying angle a. The angle a can be the same for all nozzles of the plurality of nozzles 151, 152, 153 and/or vary from nozzle to nozzle. For instance, the angle a can be equal to or greater than 160°, specifically equal to or greater than 120°, particularly equal to or greater than 90° and/or equal to or smaller than 90°, specifically equal to or smaller than 60°, particularly equal to or smaller than 30°.

[0048] Depending on a distance d between the substrate 10 and the nozzles of the plurality of nozzles 151, 152, 153, specifically each nozzle of the plurality of nozzles 151,

152, 153, can coat an area of the substrate 10 having a width w. The width w multiplied with an amount of the nozzles of the plurality of nozzles 151, 152, 153 can be equal to, greater than and/or smaller than the lateral dimension of the substrate 10 in the transverse direction TD.

[0049] The distance d between the substrate 10 and the nozzle arrangement 150 can be relatively small, e.g. compared to the lateral dimension of the substrate 10 in the transverse direction TD. For instance, the distance d can be equal to or greater than 50 cm, specifically equal to or greater than 20 cm, particularly equal to or greater than 10 cm and/or equal to or smaller than 10 cm, specifically equal to or smaller than 5 cm, particularly equal to or smaller than 1 cm When practicing embodiments, the nozzle arrangement 150 can be brought close enough to the substrate 10 so that the liquid L is sprayed on the substrate 10 without a noteworthy amount of the liquid L being diffused into the vacuum processing chamber 100. Thus, pollution of the vacuum processing chamber can be avoided in practice.

[0050] According to embodiments, the vacuum processing chamber 100 can be evacuated to a vacuum pressure level. The vacuum pressure level, i.e. the pressure level in the vacuum processing chamber 100 during processing of the substrate 10, can be a pressure below atmospheric pressure. For instance, the vacuum processing chamber can include or can be connected to components and equipment allowing for generating or maintaining a vacuum in the vacuum processing chamber 100 or a main volume of the vacuum processing chamber 100. Respective components and/or equipment can include vacuum pumps, evacuation ducts, vacuum seals and the like for generating or maintaining the vacuum in the vacuum processing chamber 100. For instance, the vacuum processing chamber 100 can have one or more vacuum pumps for evacuating the vacuum processing chamber 100. In some embodiments, two or more suitable vacuum pumps may be connected to the vacuum processing chamber 100.

[0051] Accordingly, the vacuum processing chamber 100 can form a vacuum tight enclosure, i.e. can be evacuated to a vacuum with a pressure of 10 mbar or less, particularly 1 mbar or less, or even to a pressure between lxl 0 ⁴ and lxl 0 ² mbar or less during deposition. Different pressure ranges are to be considered specifically for PVD processes such as sputtering, which may be conducted in the l0^_3-mbar range, and CVD processes, which are typically conducted in the mbar-range. Further, the vacuum chambers can be evacuated to a background vacuum with a pressure of lxl 0 ⁶ mbar or less. Background pressure can be understood as the pressure which is reached by evacuation of a chamber without any inlet of any media.

[0052] According to embodiments, the vacuum pressure level may be provided in a main volume of the vacuum processing chamber 100, where the substrate 10 is processed, e.g. transported and coated. Therein, the vacuum pressure level can be below 10 mbar or below 1 mbar during deposition.

[0053] Although the nozzle arrangement 150 is exemplary shown in Fig. 1 as including a plurality of nozzles 151, 152, 153 containing three nozzles, the nozzle arrangement 150, specifically the plurality of nozzles 151, 152, 153, can include a greater or smaller number of nozzles such as one nozzle, two nozzles, four nozzles or more nozzles. The amount of nozzles of the nozzle arrangement 150, specifically the plurality of nozzles 151, 152, 153, can depend upon the lateral dimension of the substrate 10 in the transverse direction TD, the gap d between the nozzles, the distance d to the substrate 10, the spraying angle a and/or a thickness of the coating to be formed. [0054] Figs. 2A, 2B and 2C show vacuum processing chambers 100 according to embodiments.

[0055] As shown in FIGs. 2A, 2B and 2C, the transport system can include a first substrate support 22 and a second substrate support 24 arranged at a distance from the first substrate support 22. The substrate 10 may be carried and conveyed from the first substrate support 22 to the second substrate support 24 along the substrate transportation path P (indicated by the circle having a dot in the center so as to indicate the substrate transportation path P being perpendicular to the plane of projection). The nozzle arrangement 150 can be provided at a position between the first substrate support 22 and the second substrate support 24. The area between the first substrate support 22 and the second substrate support 24, where the substrate 10 is not supported on a substrate support surface, may also be referred to as“free span” or“free span position”, as shown in Figs. 2 A and 2B.

[0056] As shown in Fig. 2C, a further substrate support 26 can be provided between the first substrate support 22 and the second substrate support 24, particularly opposite to the nozzle arrangement 150. Specifically, the further substrate support 26 can be tempered. Specifically, the further substrate support 26 can be cooled or heated. When practicing embodiments, cooling can improve condensation and/or reduce contamination of the processing chamber. Elevated temperature can improve flow properties of the liquid film and/or the liquid droplets on the substrate to increase homogeneity of the liquid film and/or coating.

[0057] According to embodiments, the transport system may be configured to guide the substrate 10 at a speed of 1 m/s or more, particularly 5 m/s or more, more particularly 10 m/s or more, or even 15 m/s or more. A high speed R2R coating system may be provided. A reliable coating of the substrate may be possible in spite of the high guiding speed of the substrate. The guiding speed of the substrate may be determined by an active roller, also referred to as the “master roller”, which may be preset to rotate at a predetermined rotation speed. One or more further active rollers may be tension- controlled rollers such that the tension of the substrate can be controlled as appropriate and an extensive or an insufficient substrate tension can be avoided. [0058] According to some embodiments, the transport system may be configured for a lower guiding speed of the flexible substrate, e.g. a guiding speed of 10 m/min or less.

[0059] Further, a shielding device 156 or housing 156 can be provided. Specifically, the nozzle arrangement 150 can include the housing 156. The housing 156 can be provided at least partially around the nozzle arrangement 150. Specifically, the housing 156 can at least partially surround and/or encompass the nozzle arrangement 150. At least some parts of the housing 156 can be provided between the nozzle arrangement 150 and the substrate 10. The housing 156 can be provided with a slit to permit the liquid L to be sprayed through the slit on the substrate 10. Additionally or alternatively, the housing 156 can be free of parts between the nozzle arrangement 150 and the substrate 10. Specifically, the housing 156 can be open to the substrate 10. The housing 156 can include parts delimiting the nozzle arrangement laterally and/or parts that run parallel to a surface of the substrate 10. The parts running parallel to the surface of the substrate 10 can be arranged relatively close to the surface of the substrate, e.g. compared to the nozzle arrangement. For instance, the liquid can be confined within the housing 156. When practicing embodiments, diffusion of the liquid L into the vacuum processing chamber 100 can be permitted. Thus, pollution of the vacuum processing chamber can be avoided in practice.

[0060] Fig. 2A shows exemplary a housing 156 including side parts for delimiting the nozzle arrangement laterally and/or bottom parts running parallel to a surface of the substrate 10. The bottom parts can be arranged between the side parts and with a gap between the bottom parts. The gap can form a slit to permit the liquid L to be sprayed through the slit on the substrate 10.

[0061] Fig. 2B shows exemplary a housing 156 including side parts for delimiting the nozzle arrangement laterally, top parts running parallel to a surface of the substrate 10, and/or bottom parts running parallel to a surface of the substrate 10. The top parts can be arranged between the side parts and so as to interpose the nozzle arrangement 150 between the top parts. The bottom parts can be arranged outside of the side parts.

[0062] Fig. 2C shows exemplary the nozzle arrangement 150 being arranged so as to face the first substrate support 22. In the configuration, the first substrate support 22 can function as the further substrate support to obtain the tempering effect described herein. [0063] The nozzle arrangement 150 can be connected to a liquid container 158. The liquid container 158 can be configured for containing a reservoir of the liquid L. The liquid container 158 can be connected to the nozzle arrangement 150 by a liquid tube 159. Specifically, the liquid L can be delivered from the liquid container 158 to the nozzle arrangement 150 through the liquid tube 159.

[0064] In the embodiment exemplarily shown in FIGs. 2A, 2B and 2C, the nozzle arrangement 150 is arranged inside the vacuum processing chamber 100, e.g. inside a main volume of the vacuum processing chamber 100 in which the substrate 10 is processed, and the liquid container 158 is arranged outside the vacuum processing chamber 100, i.e. in an atmospheric environment with a second pressure level (for example atmospheric pressure) different from the vacuum pressure level in the vacuum processing chamber 100 or the main volume of the vacuum processing chamber 100.

[0065] According to embodiments described herein, one or more vacuum feed-throughs may be arranged in a wall of the vacuum processing chamber 100 for supplying the nozzle arrangement with the liquid L, e.g. water, electricity, a control signal, a detector signal, and an operating voltage. For example, one or more vacuum feed-throughs may be provided for introducing the liquid tube 159, one or more power cables and/or one or more control cables into the vacuum processing chamber 100.

[0066] As shown in FIGs. 3 A and 3B, the vacuum processing chamber 100 can further include a curing device 160 configured for curing the liquid film 110 sprayed on the substrate 10. The curing device 160 can be arranged downstream of the nozzle arrangement 150. That is, the curing device 160 can be arranged after the nozzle arrangement 150 along the substrate transportation path P. Specifically, the nozzle arrangement 150 can be configured to form a liquid film 110 on the substrate. The liquid film 110 can be transformed to a solid or solid-like state to form the coating. According to embodiments described herein, the liquid film can be cured to form the coating.

[0067] The liquid L or aerosol A sprayed on the substrate 10 can include a monomer, oligomer and/or polymer, specifically in the polymer composition. The liquid film can thus include a layer of monomer, oligomer and/or polymer. The curing device 160 can be configured for crosslinking the liquid L sprayed on the substrate 10 by crosslinking the monomer, oligomer and/or polymer. That is the liquid L can include a crosslinkable polymer composition.

[0068] For instance, the curing device 160 can include an e-beam curing device, such as an electron beam apparatus, or an UV curing device, such as an UV light source, an electrical discharge apparatus or another suitable device.

[0069] As shown in Fig. 3 A, the curing device 160 can be arranged facing a free span position. Further, the curing device 160 can be arranged facing a substrate support. Furthermore, the nozzle arrangement 150 or the curing device 160 can be arranged in a free span position whereas the other one of the nozzle arrangement 150 and the curing device 160 can be arranged facing a substrate support. For instance, as shown in Fig. 3B, the curing device 160 can be arranged facing the second substrate support 24 which can function as a curing substrate support. Specifically, the curing substrate support can be tempered. Specifically, the curing substrate support can be cooled. When practicing embodiments, cooling can avoid evaporation of the liquid film, reduce contamination of the processing chamber and/or compensate for generated heat by the curing device to avoid thermal impacts on and/or damages of the substrate.

[0070] FIG. 4 shows a schematic side view of a vacuum processing chamber 100 for forming the coating on the substrate 10 according to embodiments described herein. According to embodiments described herein, the vacuum processing chamber 100 can be a roll-to-roll vacuum processing chamber.

[0071] In the embodiment shown in FIG. 4, the vacuum processing chamber 100 houses a coating drum 201 configured for guiding the substrate 10 past one or more deposition units 202 and a wind-up spool 203 for winding the substrate 10 thereon after deposition. A roller assembly for guiding the substrate 10 along the substrate transportation path P is shown, wherein the roller assembly includes the first substrate support 22 and the second substrate support 24 arranged at a distance from the first substrate support 22. The second substrate support 24 may be arranged directly upstream from the wind-up spool 203.

[0072] According to embodiments described herein, the vacuum processing chamber 100 can include one or more deposition units 202 configured for depositing one or more layers on the substrate 10. The nozzle arrangement 150 can be arranged downstream of the one or more deposition units 202. Further, the nozzle arrangement 150 can be configured for forming the coating on the one or more layers. According to embodiments, at least one layer is formed, specifically deposited, on the substrate 10 prior to and/or after spraying the liquid film 110 on the substrate 10. When practicing embodiments, the liquid film and/or coating can be used to smoothen the surface of the substrate. For instance, a, e.g. functional, layer formed on the liquid film and/or coating can have improved characteristics, such as improved barrier characteristics, e.g. by being formed with less pinholes due to the smoothen surface.

[0073] Fig. 4 shows the nozzle arrangement 150 and the curing device being arranged downstream of the one or more deposition units 202. Such an arrangement can be e.g. beneficial for providing a protective coating on functional layers deposited by the one or more deposition units 202 and/or for increase adhesion to a layer formed subsequently on the coating, e.g. during a subsequent converting process. Alternatively, the nozzle arrangement 150 and the curing device being arranged upstream of the one or more deposition units 202. Such an arrangement can be beneficial e.g. for providing a smooth and homogenous surface onto which the layers deposited by the one or more deposition units 202 can be deposited, which may lead to an increased barrier function of the layers deposited on the coating. Further, the coating formed before depositing layers by the one or more deposition units 202 can increase adhesion of the functional layers deposited by one or more deposition units 202.

[0074] According to embodiments described herein, the transport system configured to transport the substrate 10, specifically the flexible substrate 10, along the substrate transportation path P can be a roller assembly including a plurality of guiding rollers configured to guide the flexible substrate on a respective roller surface. At least one roller may be an active roller with a drive or motor for rotating the roller. In some embodiments, more than one active rollers may be provided. For example, a storage spool, the coating drum and/or the wind-up spool may be active rollers. In some embodiments, the roller assembly may include one or more passive rollers.

[0075] An“active” roller or roll as used herein may be understood as a roller that is provided with a drive or a motor for actively moving or rotating the respective roller. For example, an active roller may be adjusted to provide a predetermined torque. Active rollers can be configured as substrate tensioning rollers configured for tensioning the substrate with a predetermined tensioning force during operation. A“passive” roller as used herein may be understood as a roller or roll that is not provided with a drive for actively moving or rotating the passive roller. The passive roller may be rotated by the frictional force of the flexible substrate that may be in direct contact with an outer roller surface during operation.

[0076] In the context of the present disclosure, a“roll” or“roller” may be understood as a device which provides a surface with which the substrate 10, specifically the flexible substrate 10, or part of the substrate may come into contact during transport of the substrate along the substrate transportation path in the deposition apparatus. At least a part of the roller as referred to herein may include a circular-like shape for contacting the substrate 10 during transport. The substantially cylindrical shape may be formed about a straight longitudinal axis. According to some embodiments, a roller may be a guiding roller adapted to guide a substrate while the substrate is transported, e.g. during a deposition process or while the substrate is present in the deposition apparatus. The roller may be configured as a spreader roller, i.e. an active roller adapted for providing a defined tension for the flexible substrate, a processing roller, e.g. a coating drum, for supporting the flexible substrate while being coated, a deflecting roller for deflecting the substrate along the curved substrate transportation path, an adjusting roller, a storage spool, a wind- up spool, etc. According to embodiments, none, some or all of the rollers or substrate supports can be tempered, specifically cooled and/or heated. For instance, one, some or all of the rollers or substrate supports can be cooled for one process and heated for another process.

[0077] The first substrate support 22 may be a first roller of the roller assembly, and the second substrate support 24 may be a second roller of the roller assembly. The first roller and the second roller may be adjacent rollers with a gap formed therebetween for conducting a transmission measurement on the free-span portion of the substrate between the first roller and the second roller. [0078] FIG. 5 shows a flow diagram of a method for forming a coating on a substrate 10 in a vacuum processing chamber 100 according to embodiments described herein.

[0079] According to optional box 910, the substrate 10 is guided through the vacuum processing chamber 100 along a substrate transportation path P. The vacuum processing chamber 100 can be evacuated to a vacuum pressure level. According to optional box 920, the substrate 10 can be guided past one or more deposition units 202 provided in the vacuum processing chamber 100 such that one or more layers can be deposited on the substrate 10. According to box 930, a liquid film 110 is formed on the substrate 10 by spraying a liquid L on the substrate 10. Specifically, a liquid L can be atomized, specifically for forming an aerosol A. Further, the aerosol A can be sprayed on the substrate 10, specifically for forming the liquid film 110. Atomizing and spraying of the liquid L can be performed concurrently and/or form a single process. Specifically, the nozzle arrangement can be configured to atomize and spray the liquid on the substrate. According to optional box 940, the liquid film 110 sprayed on the substrate 10 can be cured. Specifically, the aerosol sprayed on the substrate 10 can form a liquid film 110, which can be cured for forming a coating. When practicing embodiments, the coating can provide a surface having modified properties with regard to friction, tension, wettability and/or printability, can provide a smooth or plane surface, a protective function and/or a barrier enhancement function. For instance, the coating may be provided on a substrate having improper surface properties, such as high surface friction, to provide a surface having increased surface properties, e.g. a smooth surface with low surface friction.

[0080] According to embodiments described herein, coatings having a thickness of less than 1 pm. While it may be generally considered to form the coating as thin as possible, to e.g. save costs for the liquid, the coating may be formed with a minimum thickness for achieving an intended function. For instance, there may be a tendency to form barrier layers thicker than protective layers, while of course there may exist a particular example of a barrier layer that may be formed thinner than a particular example of a protective layer. Accordingly, the thickness of the coating may be equal to or less than 0.8 pm, particularly equal to or less than 0.5 pm, specifically equal to or less than 0.3 pm for e.g. barrier layers and/or equal to or less than 0.2 pm, particularly equal to or less than 0.1 pm, specifically equal to or less than 0.05 pm for e.g. protective layers. [0081] Furthermore, additional layers can be formed on the coating. For instance, functional layers can be formed on the coating. When practicing embodiments, a surface of the substrate can be made planar by the coating.

[0082] Although the present disclosure particularly relates to a flexible substrate processed in a roll-to-roll vacuum processing chamber, the coating can be also formed vy the liquid on an inflexible substrate, which can be, e.g., transported along the transportation path P. Accordingly, the term“substrate” can encompass flexible and inflexible substrates.

[0083] 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. For instance, according to embodiments, a vacuum processing system is provided that includes at least one vacuum processing chamber described herein.

Claims

1. A method for forming a coating on a substrate (10) in a vacuum processing chamber (100), the method comprising:

forming a liquid film (110) on the substrate (10) by spraying a liquid (L) on the substrate (10), wherein the coating is formed to a thickness of less than 1 pm.

2. The method according to claim 1, further comprising: curing the liquid film (110) on the substrate (10).

3. The method according to claim 1 or 2, wherein the liquid (L) is, particularly mechanically, atomized to fine liquid droplets, particularly wherein the liquid droplets have a diameter mostly equal to or smaller than 1 pm, specifically equal to or smaller than 0.5 pm, particularly equal to or smaller than 0.1 pm.

4. The method according to any one of claims 1 to 3, wherein the liquid (L) includes a liquid polymer composition.

5. The method according to any one of claims 1 to 4, wherein the liquid (L) is atomized and/or sprayed at temperature (T) below an evaporation temperature (T_eVap) of the liquid (L), particularly wherein the liquid (L) is atomized and/or sprayed at ambient temperature (T_ambient) or below ambient temperature (T_ambient).

6. The method according to any one of claims 1 to 5, wherein the liquid (L) has a low vapor pressure (p_vap), particularly equal to or lower than 1E-1 mbar at room temperature, specifically equal to or lower than 1E-2 mbar at room temperature, particularly equal to or lower than 1E-3 mbar at room temperature.

7. The method according to any one of claims 1 to 6, wherein the coating (110) is a protective coating, a barrier layer or any other functional layer, e.g. for substrate surface homogenization or for increasing adhesion of functional layers.

8. The method according to any one of claims 1 to 7, further comprising:

moving the substrate (10) along a transportation path (P) through the vacuum processing chamber (100).

9. The method according to any one of claims 1 to 8, further comprising:

evacuating the vacuum processing chamber (100) to a vacuum pressure level; and particularly

forming at least one layer on the substrate (10) prior to and/or after spraying the liquid film ( 110) on the substrate (10).

10. A vacuum processing chamber (100) for forming coating on a substrate (10), comprising:

a nozzle arrangement (150) configured for forming a liquid film (110) on a substrate (10) by spraying a liquid (L) on the substrate (10), wherein the coating has a thickness of less than 1 pm.

11. The vacuum processing chamber according to claim 10, wherein the nozzle arrangement (150) includes a plurality of nozzles (151, 152, 153) particularly arranged in a direction parallel to a transverse direction (TD) of the substrate (10).

12. The vacuum processing chamber according to claim 10 or 11, further comprising: a curing device (160) configured for curing the liquid film (110) sprayed on the substrate (10), specifically wherein the curing device (160) includes an e-beam curing device and/or an UV curing device.

13. The vacuum processing chamber according to any one of claims 10 to 12, wherein the nozzle arrangement (150), specifically a plurality of nozzles of the nozzle arrangement (150), is configured for altering a particle size of the liquid (L) spayed on the substrate (10).

14. The vacuum processing chamber according to any one of claims 10 to 13, wherein the vacuum processing chamber (100) is a roll-to-roll vacuum processing chamber.

15. A vacuum processing system configured to form a coating on a substrate and comprising a vacuum processing chamber according to any one of claims 10 to 14.