MANUFACTURING A BARRIER LAYER SYSTEM IN A CONTINUOUS ROLL-TO-ROLL PROCESS

TECHNICAL FIELD [0001] Embodiments of the present disclosure relate to barrier layer systems adapted for use in an electro-optical device and methods for manufacturing such barrier layer systems in a continuous roll-to-roll process. In particular, embodiments of the present disclosure relate to barrier layer systems including a stack of layers deposited on a flexible substrate. More specifically, embodiments of the present disclosure relate to barrier layer systems which are manufactured by a continuous roll-to-roll vacuum deposition process.

BACKGROUND

[0002] Processing of flexible substrates, such as plastic films or foils, is in high demand in the packaging industry, semiconductor industries and other industries. Processing may consist of coating a flexible substrate with a desired material, such as a metal, in particular aluminum, semiconductors and dielectric materials, etching and other processing steps conducted on a substrate for the desired applications. Systems performing this task typically include a process drum, e.g., a cylindrical roller, coupled to a processing system for transporting the substrate, and on which at least a portion of the substrate is processed. Accordingly, roll-to-roll (R2R) coating systems can provide a high throughput system.

[0003] Typically, a process, e.g. a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, and a plasma enhanced chemical vapor deposition (PECVD) process, can be utilized for depositing thin layers of metals which can be coated onto flexible substrates. In particular, roll-to-roll deposition systems are experiencing a strong increase in demand in the display industry and the photovoltaic (PV) industry.

[0004] Examples of products made of a coated flexible substrate are touch panels or organic light emitting diode (OLED) displays, which have received significant interest recently in display applications in view of their faster response times, larger viewing angles, higher contrast, lighter weight, lower power, and amenability to flexible substrates, as compared to liquid crystal displays (LCD). [0005] Therefore, over the years, electro-optical devices, e.g. display devices or touch panels, have evolved into multiple layer systems in which different layers have different functions. However, the quality of conventional multilayer systems still needs to be improved, for instance with respect to barrier properties. In particular, organic light emitting devices can suffer from reduced output or premature failure when exposed to water vapor or oxygen.

[0006] In light of the foregoing, there is a need to provide barrier layer systems adapted for use in electro-optical devices and methods for manufacturing such barrier layer systems that overcome at least some of the problems in the art.

SUMMARY

[0007] In light of the above, a barrier layer system and a method for manufacturing a barrier layer system according to the independent claims are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0008] According to an aspect of the present disclosure, a barrier layer system adapted for use in an electro-optical device is provided. The barrier layer system includes a flexible substrate, a first barrier layer and a second barrier layer. The first barrier layer and the second barrier layer are configured to have barrier properties against water/oxygen permeation. Further, the barrier layer system includes a polymeric buffer layer provided between the first barrier layer and the second barrier layer. The polymeric buffer layer is configured to increase a permeation path length between the first barrier layer and the second barrier layer.

[0009] According to another aspect of the present disclosure, a barrier layer system adapted for use in an electro-optical device is provided. The barrier layer system includes a flexible substrate of polymeric material, a first barrier layer and a second barrier layer, wherein the first barrier layer and the second barrier layer are configured to have barrier properties against water/oxygen permeation. A barrier layer thickness T _BR1 of the first barrier layer is 50 nm < T _BR1 < 125 nm and a barrier layer thickness T _BR2 of the second barrier layer is 50 nm < T _BR2 ≤ 125 nm. Further, the first barrier layer and the second barrier layer are made of SiN _x and the first barrier layer and the second barrier layer each have a fracture toughness K _Ic of 4 MPa m ^{0 5} < K _Ic < 6 MPa m ⁰ - ⁵ . Further, the barrier layer system includes a polymeric buffer layer provided between the first barrier layer and the second barrier layer. The polymeric buffer layer is configured to increase a permeation path length between the first barrier layer and the second barrier layer, wherein a buffer layer thickness T _BF of the polymeric buffer layer is 250 nm ≤ T _BF < 350 nm, and wherein the polymeric buffer layer is made of nHA/EGDA20. [0010] According to a further aspect of the present disclosure, an electro- optical device having a barrier layer system according to any embodiments described herein is provided.

[0011] According to yet another aspect of the present disclosure, a method for manufacturing a barrier layer system in a continuous roll-to-roll process is provided. The method includes providing a flexible substrate to at least one first processing zone, at least one second processing zone, and at least one third processing zone without breaking vacuum. Further, the method includes depositing a first barrier layer of inorganic material on the flexible substrate in the at least one first processing zone, depositing a buffer layer of organic material on the first barrier layer in the at least one second processing zone, and depositing a second barrier layer of inorganic material on the buffer layer in the at least one third processing zone. In particular, depositing the first barrier layer, depositing the buffer layer and depositing the second barrier layer includes using the same precursor. [0012] 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 [0013] 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: FIGS. 1 and 2 show schematic views of a barrier layer system according to embodiments described herein; shows a detailed view of a portion of a barrier layer system according to embodiments described herein for illustrating the function of the polymeric buffer layer; shows a schematic view of a barrier layer system according to further embodiments described herein; shows a detailed view of a portion of the barrier layer system of FIG. 4 A for illustrating the function of the polymeric buffer layers; shows a schematic view of a processing system for manufacturing a barrier layer system according to embodiments described herein; shows a schematic view of an electro-optical device having a barrier layer system according to embodiments described herein; and shows a flow chart illustrating a method for manufacturing a barrier layer system in a continuous roll-to-roll process according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS [0014] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is 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 yet a further embodiment. It is intended that the present disclosure includes such modifications and variations. [0015] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment can apply to a corresponding part or aspect in another embodiment as well.

[0016] Before various embodiments of the present disclosure are described in more detail, some aspects with respect to some terms and expressions used herein are explained. [0017] In the present disclosure, a "barrier layer system" is to be understood as a stack of layers having barrier properties against water vapor and oxygen transmission. In particular, a "barrier layer system" as described herein can include alternating layers (diades) including a polymeric buffer layer and a barrier layer. Typically, the barrier layer includes SiN _x and the polymeric buffer layer includes polyethylene glycol methacrylate (PGMA) and/or ethylene glycol diamine (EGDA). More specifically, a barrier layer system as described herein can be understood as a ultrahigh barrier (UHB) system having a water vapor transmission rate (WVTR; in units of g per cm ² and day) and/or an oxygen transmission rate (OTR; in units of g per cm ² and day) of less than 10 ^~4 , specifically less than 10 ^~5 , and more specifically less than lO ⁶ . In particular, a barrier layer system as described herein can be transparent. The term "transparent" as used herein can particularly include the capability of a structure to transmit light with relatively low scattering, so that, for example, light transmitted therethrough can be seen in a substantially clear manner.

[0018] In the present disclosure, a "flexible substrate" may be characterized in that the substrate is bendable. For example, the flexible substrate may be a foil. In particular, it is to be understood that a flexible substrate as described herein can be processed in a continuous roll-to-roll process as described herein, for instance in a roll-to-roll processing system as described herein. In particular, the flexible substrate as described herein is suitable for manufacturing coatings or electronic devices on the flexible substrate. In particular, a flexible substrate as described herein can be transparent, e.g. the flexible substrate may be made of a transparent polymer material. More specifically, a flexible substrate as described herein may include materials like polyethylene terephthalate (PET), polycarbonate (PC), polyethylene (PE), polyimide (PI), polyurethane (PU), poly(methacrylic acid methyl ester), triacetyl cellulose, cellulose triacetate (TAC), cyclo olefin polymer, poly(ethylene naphthalate), one or more metals, paper, combinations thereof, and already coated substrates like Hard Coated PET (HC-PET) or Hard Coated TAC (HC-TAC) and the like.

[0019] In the present disclosure, a "barrier layer" is to be understood as a layer having barrier properties against water vapor and oxygen transmission. In particular, a barrier layer as described herein can have water vapor transmission rate WVTR of less than 3x 10 ³ g/m ² per day. For instance, a barrier layer of the present disclosure can include SiN _x , particularly consist of SiN _x .

[0020] In the present disclosure, a "polymeric buffer layer" is to be understood as a layer of polymeric material including polyethylene glycol methacrylate (PGMA) and/or ethylene glycol diamine (EGDA). In particular, a polymeric buffer layer as described herein is to be understood as a layer configured to increase a permeation path length, e.g. for water vapor or oxygen, through the buffer layer, for instance from one side of the buffer layer to an opposing other side of the buffer layer. [0021] In the present disclosure, a "permeation path length" is to be understood as the length of a path a molecule travels when the molecule permeates through a material, e.g. through the polymeric buffer layer as described herein.

[0022] FIG. 1 shows a schematic view of a barrier layer system 100 according to embodiments described herein. According to embodiments which can be combined with any other embodiments described herein, the barrier layer system 100 adapted for use in an electro-optical device includes a flexible substrate 101 , a first barrier layer 1 10 and a second barrier layer 120. For example, the flexible substrate 101 may include a polymer material selected from the group consisting of: polycarbonate, polyethylene terephthalate, poly(methacrylic acid methyl ester), triacetyl cellulose, cyclo olefin polymer, and poly(ethylene naphthalate). In particular, the first barrier layer 1 10 and the second barrier layer 120 are configured to have barrier properties against water/oxygen permeation. Further, the barrier layer system includes a polymeric buffer layer 1 15 provided between the first barrier layer 1 10 and the second barrier layer 120, as exemplarily shown in FIG. 1. More specifically, as described in more detail with respect to FIG. 3, the polymeric buffer layer 1 15 is configured to increase a permeation path length between the first barrier layer 1 10 and the second barrier layer 120.

[0023] Accordingly, an improved barrier layer system is provided. In particular, embodiments of the barrier layer system as described herein provide for a layer system having improved barrier properties with respect to water vapor or oxygen compared to conventional barrier layer systems. Thus, by employing embodiments of the barrier layer system as described herein in electro-optical devices, e.g. display devices or touch panels, an improved product durability of the electro-optical devices can be achieved.

[0024] According to embodiments which can be combined with any other embodiments described herein, a thickness ratio TR of a buffer layer thickness T _BF of the polymeric buffer layer 1 15 to a barrier layer thickness T _BR I of the first barrier layer 1 10 can be 1.5 < TR = T _BF / T _BR1 < 4. For instance, the thickness ratio TR may be TR=3, e.g. for a configuration in which the buffer layer thickness T _BF = 300 nm and the barrier layer thickness T _BR1 of the first barrier layer 1 10 is T _BR1 = 100 nm. According to another example, the thickness ratio TR may be TR=1.6, e.g. for a configuration in which the buffer layer thickness T _BF = 400 nm and the barrier layer thickness T _BR I of the first barrier layer 1 10 is T _BR I = 150 nm.

[0025] Accordingly, it is to be understood that if two values for the three parameters: thickness ratio TR; buffer layer thickness T _BF of the polymeric buffer layer; and the barrier layer thickness T _BR1 of the first barrier layer are known, the remaining third value can be calculated from the equation

TR = T _BF /

[0026] According to embodiments which can be combined with any other embodiments described herein, the polymeric buffer layer 1 15 may have a thickness T _BF of approximately 400 nm, particularly approximately 300 nm, more particularly approximately 250 nm. It is to be understood that in the present disclosure, the term "approximately" shall include values deviating from the associated value by ± 5%. Accordingly, for example, approximately 400 nm is to be understood as 400 nm ± 20 nm. [0027] Accordingly, by providing a barrier layer system having a polymeric buffer layer as described herein, the barrier properties of the barrier layer system with respect to water vapor or oxygen is improved. Further, a thickness ratio TR of a buffer layer thickness T _BF of the polymeric buffer layer to a barrier layer thickness T _BR i of the first barrier layer may in particular be beneficial for increasing the barrier properties of the barrier layer system as described herein.

[0028] With exemplary reference to FIG. 2, according to some embodiments which can be combined with other embodiments described herein, the barrier layer system 100 may include a first polymeric buffer layer 1 14 provided between the flexible substrate 101 and the first barrier layer 1 10. In particular, the first polymeric buffer layer 1 14 may be configured to increase a permeation path length between the flexible substrate 101 and the first barrier layer 1 10. Further, the first polymeric buffer layer 1 14 may have a thickness T _BF1 corresponding to the thickness T _BF of the polymeric buffer layer 1 15 provided between the first barrier layer 110 and the second barrier layer 120. More specifically, the first polymeric buffer layer 114 can include at least one material selected form the group consisting of: PGMA, EGDA, and nHA/EGDA (nHexa- Acrylate/ethylene glycol diamine, particularly nHA/EGDA20. [0029] Accordingly, by providing a barrier layer system having a first polymeric buffer layer 114 provided between the flexible substrate 101 and the first barrier layer 110, the barrier properties with respect to water vapor or oxygen of the barrier layer system can be improved.

[0030] According to some embodiments which can be combined with other embodiments described herein, a thickness ratio TR1 of a first buffer layer thickness T _BF I of the first polymeric buffer layer 114 to a barrier layer thickness T _BR I of the first barrier layer 110 can be 1.5 < TR1 = T _BF I / T _B Ri≤ 4. For instance, the thickness ratio TR1 may be TR1=3, e.g. for a configuration in which the first buffer layer thickness T _BF1 = 300 nm and the barrier layer thickness T _BR I of the first barrier layer 110 is T _BR I = 100 nm. According to another example, the thickness ratio TR1 may be TR1=1.6, e.g. for a configuration in which the first buffer layer thickness T _BF I ⁼ 400 nm and the barrier layer thickness T _BR1 of the first barrier layer 110 is T _BR I ⁼ 150 nm. [0031] Accordingly, it is to be understood that if two values for the three parameters: thickness ratio TR1; buffer layer thickness T _BF I of the first polymeric buffer layer; and the barrier layer thickness T _BR I of the first barrier layer are known, the remaining third value can be calculated from the equation TR1 = T _BF I / T _BR I. A thickness ratio TR1 as described herein may in particular be beneficial for increasing the barrier properties of the barrier layer system as described herein.

[0032] According to embodiments which can be combined with any other embodiments described herein, the barrier layer thickness T _BR I of the first barrier layer 110 is 50 nm < T _BR I < 300 nm. For instance, the barrier layer thickness T _BR I of the first barrier layer 110 can be selected from a range having a lower limit of 50 nm, particularly a lower limit of 75 nm, more particularly a lower limit of 100 nm and an upper limit of 200 nm, particularly an upper limit of 250 nm, more particularly an upper limit of 300 nm. According to some examples, the barrier layer thickness T _BR1 of the first barrier layer 110 can be approximately 100 nm; approximately 150 nm, approximately 200 nm, or approximately 250 nm.

[0033] According to embodiments which can be combined with any other embodiments described herein, a barrier layer thickness T _BR2 of the second barrier layer 120 is 50 nm < T _BR2 < 300 nm. For instance, the barrier layer thickness T _BR2 of the second barrier layer 120 can be selected from a range having a lower limit of 50 nm, particularly a lower limit of 75 nm, more particularly a lower limit of 100 nm and an upper limit of 200 nm, particularly an upper limit of 250 nm, more particularly an upper limit of 300 nm. According to some examples, the barrier layer thickness T _BR2 of the second barrier layer 120 can be approximately 100 nm; approximately 150 nm, approximately 200 nm, or approximately 250 nm.

[0034] According to embodiments which can be combined with any other embodiments described herein, the polymeric buffer layer 115 may include at least one material selected form the group consisting of: PGMA, EGDA, and nHA/EGD A, particularly nH A/EGD A20.

[0035] Accordingly, by providing a barrier layer system having a polymeric buffer layer as described herein, the barrier properties of the barrier layer system can be improved compared to conventional barrier layer systems. [0036] FIG. 3 shows a detailed view of a portion of a barrier layer system according to embodiments described herein for illustrating the function of the polymeric buffer layer. In particular, FIG. 3 shows the barrier layer system having a flexible substrate 101, a first barrier layer 110, a polymeric buffer layer 115, and a second barrier layer 120, as described herein. Further, in FIG. 3, defects D in the first barrier layer 110 and the second barrier layer 120 are indicated as black squares. The dotted lines from the defects D in the first barrier layer 110 through the polymeric buffer layer 115 to the defects in the second barrier layer 120 indicate the permeation path of molecules, e.g. water vapor or oxygen, permeating through the layer system. Accordingly, as shown in FIG. 3, by providing a barrier layer system having a polymeric buffer layer as described herein, the permeation path length for molecules, e.g. water vapor or oxygen, through the barrier layer system can be increased, such that the barrier properties of the barrier layer system are improved compared to conventional barrier layer systems. [0037] According to embodiments which can be combined with any other embodiments described herein, the first barrier layer 110 and the second barrier layer 120 include SiN _x . In particular, the first barrier layer and the second barrier layer may consist of SiN _x . Such a configuration may in particular be beneficial for improving the barrier properties of the barrier layer system with respect to water vapor or oxygen. Further, the fracture toughness K _lc of the first barrier layer and/or the second barrier layer can be 4 MPa m ^{0 5} < K _Ic < 6 MPa m ^{0 5} .

[0038] According to embodiments which can be combined with any other embodiments described herein, a water vapor transmission rate WVTR of the first barrier layer 110 is less than 3x 10 ³ g/m ² per day. For instance, the water vapor transmission rate WVTR of the first barrier layer 110 can be approximately 2x 10 ^{" 3} g/m ² per day. In particular, it is to be understood that the water vapor transmission rate WVTR is typically measured with a permeation unit, e.g. the permeation unit "Aquatran 2", at 40°C and 100% relative humidity (RH). In this regard, it is to be noted that typically as the temperature and the relative humidity is decreased, the measured water vapor transmission rate decreases as well. For example, at 20°C and 50% relative humidity (RH), the measured WVTR can be approximately 10 times lower than at 40°C and 100% relative humidity (RH). [0039] According to embodiments which can be combined with any other embodiments described herein, a water vapor transmission rate WVTR of the second barrier layer 120 is less than 3x 10 ³ g/m ² per day. For instance, similar to the first barrier layer 110, the water vapor transmission rate WVTR of the second barrier layer 120 can be approximately 2x 10 ^{" 3} g/m ² per day, e.g. measured with the permeation unit "Aquatran 2", at 40°C and 100% relative humidity (RH).

[0040] With exemplary reference to FIG. 4A , according to embodiments which can be combined with any other embodiments described herein, the barrier layer system 100 further comprises at least one layer stack 130 provided on the second barrier layer 120. In particular, the at least one layer stack 130 can include a further polymeric buffer layer 135 and a further barrier layer 140. In particular, the further polymeric buffer layer 135 may be configured to increase a permeation path length between the second barrier layer 120 and the further barrier layer 140. More specifically, the further polymeric buffer layer 135 may include at least one material selected from the group consisting of: PGMA, EGDA, and nHA/EGDA, particularly nHA/EGDA20. Further, the further polymeric buffer layer 135 may have a thickness of approximately 400 nm, particularly approximately 300 nm, more particularly approximately 250 nm.

[0041] According to embodiments which can be combined with any other embodiments described herein, the further barrier layer 140 can include SiN _x . In particular, the further barrier layer 140 may consist of SiN _x . Further, the barrier layer thickness T _BRF of the further barrier layer 140 can be 50 nm < T _BRF ≤ 300 nm. For instance, the barrier layer thickness T _BRF of the further barrier layer 140 can be selected from a range having a lower limit of 50 nm, particularly a lower limit of 75 nm, more particularly a lower limit of 100 nm and an upper limit of 200 nm, particularly an upper limit of 250 nm, more particularly an upper limit of 300 nm. According to some examples, the barrier layer thickness T _BRF of the further barrier layer 140 can be approximately 100 nm; approximately 150 nm, approximately 200 nm, or approximately 250 nm.

[0042] According to embodiments which can be combined with any other embodiments described herein, a water vapor transmission rate WVTR of the further barrier layer 140 is less than 3 x 10 ³ g/m ² per day. For instance, similar to the first barrier layer 110 or the second barrier layer 120, the water vapor transmission rate WVTR of further barrier layer 140 can be approximately 2x 10 ^{" 3} g/m ² per day, e.g. measured with the permeation unit "Aquatran 2", at 40°C and 100% relative humidity (RH). [0043] In FIG. 4B, a detailed view of a portion of the barrier layer system of FIG. 4A is shown. In particular, FIG. 4B shows the barrier layer system having a flexible substrate 101, a first barrier layer 110, a polymeric buffer layer 115, a second barrier layer 120, a further polymeric buffer layer 135, and a further barrier layer 140, as described herein. Further, in FIG. 4B, defects D in the first barrier layer 110, the second barrier layer 120 and the further barrier layer 140 are indicated as black squares. The dotted lines from the defects D of the first barrier layer 110 through the polymeric buffer layer 115, the defects D of the second barrier layer 120, and the further polymeric buffer layer 135 to the defects D in the further barrier layer 140 indicate the permeation path of molecules, e.g. water vapor or oxygen, permeating through the layer system. Accordingly, as shown in FIG. 4B, by providing a barrier layer system having at least one layer stack 130 as described herein, the permeation path length for molecules, e.g. water vapor or oxygen, through the barrier layer system can be increased, such that the barrier properties of the barrier layer system are improved compared to conventional barrier layer systems. Accordingly, it is to be understood that by providing further layer stacks corresponding to the at least one layer stack 130, the barrier properties of the barrier layer system can be improved even further. [0044] According to an example which can be combined with other embodiments described herein, the barrier layer system 100 adapted for use in an electro-optical device includes a flexible substrate 101 of polymeric material, a first barrier layer 1 10 and a second barrier layer 120, wherein the first barrier layer and the second barrier layer are configured to have barrier properties against water/oxygen permeation. A barrier layer thickness T _B RI of the first barrier layer is 50 nm < T _B RI < 125 nm and a barrier layer thickness T _B R2 of the second barrier layer is 50 nm < T _B R2 < 125 nm. Further, the first barrier layer and the second barrier layer are made of SiN _x and the first barrier layer and the second barrier layer each have a fracture toughness Ki _c of 4 MPa m0.5 < Ki _c < 6 MPa m ^{0 5} . Further, the barrier layer system 100 includes a polymeric buffer layer 1 15 layer provided between the first barrier layer 1 10 and the second barrier layer 120. The polymeric buffer layer is configured to increase a permeation path length between the first barrier layer and the second barrier layer, wherein a buffer layer thickness T _BF of the polymeric buffer layer is 250 nm < T _BF < 350 nm, and wherein the polymeric buffer layer is made of nHA/EGDA20.

[0045] Accordingly, in view of the embodiments of the barrier layer system as described herein, it is to be understood that the barrier layer system is well suited for being manufactured in a continuous roll-to-roll process, particularly a continuous vacuum deposition roll-to-roll process.

[0046] As an example, a schematic view of a processing system 300 for manufacturing a barrier layer system according to embodiments described herein is shown in FIG. 5. In particular, FIG. 5 shows a roll-to-roll processing system configured for carrying out a method for manufacturing a barrier layer system in a continuous roll-to-roll process as exemplarily described in more detail with reference to FIG. 7.

[0047] As exemplarily shown in FIG. 5, the processing system 300 can include at least three chamber portions, such as a first chamber portion 302 A, a second chamber portion 302B and a third chamber portion 302C. At the third chamber portion 302C, one or more deposition sources 630 and optionally an etching station 430 can be provided as processing tools. A flexible substrate 101, e.g. a flexible substrate as described herein, is provided on a first roll 764, e.g. having a winding shaft. The flexible substrate is unwound from the first roll 764 as indicated by the substrate movement direction shown by arrow 108. A separation wall 701 is provided for separation of the first chamber portion 302 A and the second chamber portion 302B. The separation wall 701 can further be provided with gap sluices 740 to allow the flexible substrate 101 to pass therethrough. A vacuum flange 312 provided between the second chamber portion 302B and the third chamber portion 302C can be provided with openings to take up at least some processing tools.

[0048] The flexible substrate 101 is moved through the deposition areas provided at a coating drum 710 and corresponding to positions of the deposition sources 630. During operation, the coating drum 710 rotates around an axis such that the flexible substrate 101 moves in the direction of arrow 108. According to some embodiments, the flexible substrate 101 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 the second roll 764', e.g. having a winding shaft, on which the flexible substrate 101 is wound after processing thereof.

[0049] According to some embodiments, the deposition sources 630 can be configured for depositing the layers of the layer stack as described herein. As an example; at least one deposition source can be adapted for deposition of the first barrier layer 110, at least one deposition source can be adapted for deposition of the polymeric buffer layer 115; and at least one deposition source can be adapted for deposition of the second barrier layer 120. Further, at least one deposition source which is adapted for deposition of the further polymeric buffer layer 135 and at least one deposition source which is adapted for deposition of the further barrier layer 140 polymeric buffer layer can be provided. Additionally, a deposition source may be provided which is adapted for deposition of the first polymeric buffer layer 114.

[0050] In some implementations, the first chamber portion 302A is separated in an interleaf chamber portion unit 302A1 and a substrate chamber portion unit 302A2. For instance, interleaf rolls 766/766' and interleaf rollers 305 can be provided as a modular element of the processing system 300. The processing system 300 can further include a pre-heating unit 394 to heat the flexible substrate. Further, additionally or alternatively a pre-treatment plasma source 392, e.g. an RF (radio frequency) plasma source can be provided to treat the substrate with a plasma prior to entering the third chamber portion 302C.

[0051] According to yet further embodiments, which can be combined with other embodiments described herein, optionally also an optical measurement unit 494 for evaluating the result of the substrate processing and/or one or more ionization units 492 for adapting the charge on the substrate can be provided.

[0052] According to some embodiments, the deposition material may be chosen according to the deposition process and the later application of the coated substrate. For instance, the deposition material of the deposition sources may be selected according to the respective material of the polymeric buffer layers and the barrier layers, as described herein.

[0053] With exemplary reference to FIG. 6, according to one aspect of the present disclosure, an electro-optical device 150 having a barrier layer system 100 according to any embodiments described herein is provided. [0054] Accordingly, barrier layer systems as described herein can beneficially be used in optical applications, for instance protection of OLEDs. However, it is to be understood that the barrier layer system of the present disclosure can also be used in different applications. As an example, the barrier layer system of the present disclosures can be used in the field of packaging for instance of food for which high oxygen protection is beneficial, for example fresh pasta, sliced meat, dried fruit, or snacks. Further, the barrier layer system as described herein may provide a gas barrier and transparent properties in order provide a product's visibility. [0055] With exemplary reference to FIG. 7, embodiments of a method 200 for manufacturing a barrier layer system in a continuous roll-to-roll process is described. According to embodiments which can be combined with any other embodiments described herein, the method includes providing (see block 210) a flexible substrate to at least one first processing zone, at least one second processing zone, and at least one third processing zone without breaking vacuum. For example, the first processing zone may include a first deposition source adapted for deposition of the first barrier layer 110. The second processing zone may include a deposition source adapted for deposition of the polymeric buffer layer 115. The third processing zone may include a deposition source adapted for deposition of the second barrier layer 120.

[0056] Alternatively, e.g. for manufacturing a barrier layer system as described with reference to FIG. 2, the first processing zone may include a first deposition source adapted for deposition of the first polymeric buffer layer 114, the second processing zone may include a deposition source adapted for deposition of the first barrier layer 110, and the third processing zone may include a deposition source adapted for deposition of the polymeric buffer layer 115.

[0057] Further, the method includes depositing (see block 220) a first barrier layer 110 of inorganic material on the flexible substrate 101 in the at least one first processing zone, depositing (see block 230) a polymeric buffer layer 115 of organic material on the first barrier layer 110 in the at least one second processing zone, and depositing (see block 240) a second barrier layer 120 of inorganic material on the polymeric buffer layer 115 in the at least one third processing zone. Typically, depositing the first barrier layer 110, depositing the polymeric buffer layer 115 and depositing the second barrier layer 120 includes using the same precursor.

[0058] Alternatively, the method includes depositing (see block 220) a first polymeric buffer layer 114 of organic material on the flexible substrate in the at least one first processing zone, depositing (see block 230) a first barrier layer 110 of inorganic material on the first polymeric buffer layer 114 in the at least one second processing zone, and depositing (see block 240) a polymeric buffer layer 115 of organic material on the first barrier layer 110 in the at least one third processing zone. Typically, depositing the first polymeric buffer layer 114, depositing the first barrier layer 110, and depositing the polymeric buffer layer 115 includes using the same precursor.

[0059] According to embodiments which can be combined with any other embodiments described herein, depositing the first barrier layer 110, depositing the first polymeric buffer layer 114 and/or depositing the polymeric buffer layer 115, and depositing the second barrier layer 120 includes using a PECVD process and/or a HWCVD (Hot Wire Chemical Vapor Deposition) process. For instance, the first barrier layer 110 and/or the first polymeric buffer layer 114 and/or the polymeric buffer layer 115 and/or the second barrier layer 120 as described herein may be deposited using a low temperature microwave PECVD process.

[0060] According to embodiments which can be combined with any other embodiments described herein, using the same precursor includes using at least one precursor selected from the group consisting of: HMDSO hexamethyldisiloxane; TOMCAT Tetramethyl Cyclotetrasiloxane (C ₄ H ₁₆ 0 ₄ Si ₄ ); HMDSN Hexamethyldisilazane ([(CH ₃ )3Si] ₂ NH); and TEOS Tetraethyl Orthosilicate (Si(OC ₂ H ₅ ) ₄ ).

[0061] Further, according to some embodiments which can be combined with any other embodiments described herein, the method may include depositing at least one layer stack 130 as described herein. It is to be understood that depositing the at least one layer stack 130 includes depositing the further polymeric buffer layer 135 and depositing the further barrier layer 140. Further, it is to be understood that correspondingly adapted deposition sources can be used for depositing the further polymeric buffer layer 135 and for depositing the further barrier layer 140. The further polymeric buffer layer 135 can be deposited in accordance to the other polymeric buffer layers, e.g the polymeric buffer layer 115 or the first polymeric buffer layer 114. The further barrier layer 140 can be deposited in accordance to the other barrier layers, e.g the first barrier layer 110 or the second barrier layer 120. [0062] In light of the foregoing, it is to be understood that embodiments described herein provide for an improved barrier layer system as well as for methods for manufacturing such an improved barrier layer system, particularly for use in electro-optical devices.

[0063] 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.

[0064] In particular, this written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the described subject-matter, including making and using any devices or systems and performing any incorporated methods. While various specific embodiments have been disclosed in the foregoing, mutually non-exclusive features of the embodiments described above may be combined with each other. The patentable scope is defined by the claims, and other examples are intended to be within the scope of the claims if the claims have structural elements that do not differ from the literal language of the claims, or if the claims include equivalent structural elements with insubstantial differences from the literal language of the claims.