WO2015172847A1

WO2015172847A1 - Barrier layer stack, method for manufacturing a barrier layer stack, and ultra-high barrier layer and antireflection system

Info

Publication number: WO2015172847A1
Application number: PCT/EP2014/060134
Authority: WO
Inventors: Hans-Georg Lotz; Neil Morrison; Tobias Stolley
Original assignee: Applied Materials, Inc.
Priority date: 2014-05-16
Filing date: 2014-05-16
Publication date: 2015-11-19
Also published as: KR20170003999A; JP2017518204A; TW201611371A; CN106415873A; JP6685932B2; KR101985923B1; CN106415873B

Abstract

A barrier layer stack is provided. The barrier layer stack (10, 20, 30, 40) includes a first layer (11), a second layer (12), a third layer (13) and a fourth layer (14) arranged in this order. The first layer (11) and the third layer (13) have a refractive index of at least 1.9, and the second layer (12) and the fourth layer (14) have a refractive index of less than 1.7. Each of the layers (11-14) has a thickness of at least 70 nm.

Description

BARRIER LAYER STACK, METHOD FOR

MANUFACTURING A BARRIER LAYER STACK, AND ULTRA-HIGH BARRIER LAYER AND ANTIREFLECTION

SYSTEM

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to a barrier layer stack, a method for manufacturing a barrier layer stack, and an ultra-high barrier layer and antireflection system.

BACKGROUND ART

[0002] Organic light emitting devices (OLEDs) can suffer from reduced output or premature failure when exposed to water vapor or oxygen. Several barrier systems have been used to protect OLED devices from such water vapor or oxygen. As an example, when glass is used to encapsulate OLED devices, a structural stability of the OLED device is compromised, since glass lacks flexibility.

[0003] There is a need for a barrier system, e.g. on a substrate such as a flexible polymer substrate, that overcomes at least some of the above aspects. There is particularly a need for a barrier system that exhibits enhanced optical performance compared to conventional structures.

SUMMARY

[0004] In light of the above, a barrier layer stack, a method for manufacturing a barrier layer stack, and an ultra-high barrier layer and antireflection system are provided. Further aspects, advantages, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0005] According to an aspect of the present disclosure, a barrier layer stack is provided. The barrier layer stack includes a first layer, a second layer, a third layer and a fourth layer arranged in this order. The first layer and the third layer have a refractive index of at least 1.9, and the second layer and the fourth layer have a refractive index of less than 1.7. Each of the layers has a thickness of at least 70 nm.

[0006] According to another aspect of the present disclosure, a method for manufacturing a barrier layer stack is provided. The method includes: alternately depositing a first layer material and a second layer material on a substrate to form at least four layers, wherein the first layer material has a refractive index of at least 1.9, wherein the second layer material has a refractive index of less than 1.7, and wherein each of the layers has a thickness of at least 70 nm.

[0007] According to yet another aspect of the present disclosure, an ultrahigh barrier layer and antireflection system is provided. The ultra-high barrier layer and antireflection system includes a substrate and a layer stack over the substrate. The layer stack includes a first layer, a second layer, a third layer and a fourth layer arranged in this order. The first layer and the third layer have a refractive index of at least 1.9, and the second layer and the fourth layer have a refractive index of less than 1.7. Each of the layers has a thickness of at least 70 nm.

[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 disclosure 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 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:

[0010] Figures 1A-C show cross sectional views of barrier layer stacks according to embodiments described herein;

[0011] Figure 2 shows a cross sectional view of a barrier layer stack according to further embodiments described herein;

[0012] Figure 3 shows a graph of a reflectance of barrier layer stacks according to embodiments described herein;

[0013] Figure 4 shows a schematic view of a deposition apparatus used for manufacturing a barrier layer stack according to embodiments described herein; and

[0014] Figure 5 shows a flow chart of a method for manufacturing a barrier layer stack according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0015] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0016] Layer stacks can be used in optical applications (for instance protection of OLEDs), but they can reduce the transmittance particularly in the visible spectrum and may create undesired colors. The present disclosure overcomes this drawback by providing a barrier layer stack having combined barrier and antireflection properties. The barrier layer stack according to embodiments described herein can have color neutrality, the color neutrality providing improved optical characteristics of the barrier layer stack.

[0017] Although OLED applications have been mentioned so far, the barrier layer stack of the present disclosure can also be used in different applications. As an example, the barrier layer stack of the present disclosures can be used in the field of packaging for instance of food that requires high oxygen protection, for example fresh pasta, sliced meat, dried fruit, or snacks. The barrier layer stack may provide a gas barrier and transparent properties in order provide a product' s visibility.

[0018] The disclosure is related to barrier layer systems with low water vapor and oxygen transmission, and is particularly related to ultra-high barrier layer systems (UHB). The barrier layer stacks of the present disclosure include alternating layers (diades), and particularly include at least four layers. A thickness of the individual layers is at least 70 nm, and is particularly in the range of 70 nm to 300 nm, and more particularly in the range of 100 nm to 150 nm. Thicknesses and/or optical properties of the individual layers can be different. The barrier layer stack can include at least two materials with a low and a high refractive index. At least some of the layers of the barrier layer stack can be dielectric layers. According to some embodiments, which can be combined with other embodiments described herein, the first layer, the second layer, the third layer and the further layer are dielectric layers. In some implementations, all of the layers of the barrier layer stack are dielectric layers.

[0019] According to some embodiments, which can be combined with other embodiments described herein, the uppermost layer, i.e., the last layer arranged e.g. over the substrate such as the fourth layer, has the low refractive index. The barrier layer stack having the uppermost layer with the low refractive index provides improved optical characteristics.

[0020] An aspect of the present disclosure is to provide layer thicknesses of the individual layers in order to provide a transmittance, which is for instance higher than a transmittance of a (uncoated) substrate on which the layer stack is disposed. Particularly, an aspect of the present disclosure is to provide a transmittance, which is higher than a transmittance of a (uncoated) substrate in the visible region.

[0021] The present disclosure provides barrier layer stacks with antireflection properties. According to some embodiments, a barrier layer stack with four layers may be referred to as NONO, a barrier layer stack with five layers may be referred to as NONON and a barrier layer stack with six layers may be referred to as NONONO. The symbols N and O may denote a material of the layers. In some implementations, the symbol N denotes the material or layer with high refractive index (e.g., SiNx) and the symbol O denotes the material or layer with low refractive index (e.g., SiOx). The low refractive index can be in the range of 1.4 to 1.6, specifically about n=1.46. However, it is to be understood that the present disclosure is not limited to SiNx and SiOx, and that any suitable materials having the high refractive index of at least 1.9 and the low refractive index of less than 1.7 could be used for the layers with the high refractive index and the layers with the low refractive index, respectively. Some examples can be insulating materials with high and low refractive indexes, for example SiOx, TiOx, NbOx, SiNx, SiOxNy, AlOx, AlOxNy, TaOx, an organic material such as a polymer material, and combinations thereof. [0022] In some implementations, an extinction coefficient of the materials with the high refractive index and the low refractive index can be small. The index of refraction and the extinction coefficient are the real part and the imaginary part, respectively, of the complex index of refraction. Particularly, when light passes through a medium, some part of it will be absorbed. This can be described by defining the complex index of refraction as being equal to n+ik. The real part "n" indicates the phase velocity, while the imaginary part "ik" indicates the amount of absorption loss when the electromagnetic wave propagates through the material.

[0023] The term "refractive index" (or index of refraction) n of a material or optical medium is a dimensionless number that describes how light, or any other radiation, propagates through that material. It is defined as n=c/v, where c is the speed of light in vacuum and v is the speed of light in the material.

[0024] According to some embodiments, with an optimized layer system of the present disclosure, the transmittance of a NONO/NONONO design can be enhanced above the transmittance for instance of uncoated PET. In comparison to non-optimized NONON/NONONON designs the (absolute) transmittance gain can be in the range of about 4% to about 6% (e.g., increasing a transmittance (Ty) from about 88% to about 92-94%). The contrast/color difference may be b*<0.3 (b* value as defined by the International Commission on Illumination (CIE) in 1976).

[0025] Figures 1A-C show barrier layer stacks according to embodiments described herein. According to some embodiments, the layer stack of the present embodiments is constituted by a number of films formed (e.g., by deposition) one atop of another.

[0026] In figure 1A a barrier layer stack 10 according to embodiments of the present disclosure is depicted. The barrier layer stack 10 includes a first layer 11, a second layer 12, a third layer 13 and a fourth layer 14 arranged in this order. The first layer 11 and the third layer 13 have a refractive index of at least 1.9, and the second layer 12 and the fourth layer 14 have a refractive index of less than 1.7. Each of the layers 11-14 has a thickness of at least 70 nm.

[0027] The first layer 11 and the third layer 13 having a refractive index of at least 1.9, the second layer 12 and the fourth layer 14 having a refractive index of less than 1.7, and each of the layers 11- 14 having a thickness of at least 70 nm provide a barrier layer stack having combined barrier and antireflection functions.

[0028] According to some embodiments, which can be combined with other embodiments herein, the barrier layer stack can include one or more further layers over the fourth layer 14, particularly a fifth or a fifth and a sixth layer as it is shown in figures IB and 1C, respectively.

[0029] In figure IB a barrier layer stack 20 according to embodiments of the present disclosure is depicted. The barrier layer stack 20 is similar to the barrier layer stack 10 of figure 1 with the difference being that a fifth layer 15 is arranged over the fourth layer 14.

[0030] In figure 1C a barrier layer stack 30 according to embodiments of the present disclosure is depicted. The barrier layer stack 30 is similar to the barrier layer stack 20 of figure 2 with the difference being that a sixth layer 16 is arranged over the fifth layer 15.

[0031] In some implementations, the odd numbered layers have the refractive index of at least 1.9, and the even numbered layers have the refractive index of less than 1.7. The terms "odd" and "even" as used throughout this application refer to parity in mathematics, i.e. that an integer is even if it is evenly divisible by two and odd if it is not even. As an example, the odd numbered layers can be the first, third, fifth etc. layers, and the even numbered layers can be the second, fourth, sixth, etc. layers.

[0032] The odd numbered layers having a refractive index of at least 1.9, the even numbered layers having a refractive index of less than 1.7, and each of the layers having a thickness of at least 70 nm provide a barrier layer stack having combined barrier and antireflection functions.

[0033] The first to sixth layers, the odd numbers layers and the even numbered layers as referred to in this application are the layers providing the barrier and antireflection functions, i.e., the layers having the refractive index of at least 1.9 or the refractive index of less than 1.7, and the thickness of at least 70 nm. Thus, the numbering excludes any other layers that could additionally be provided, such as seed layers, hard coatings, adhesive layers and the like.

[0034] In some implementations, a water vapor transmission rate (WVTR; in units of g per cm² and day) and/or an oxygen transmission rate (OTR) of the barrier layer stack is less than 10^"4, specifically less than 10^"5, and more specifically about 10^"6. A transmittance of the barrier layer stack can be at least 85%, and particularly more than 90%. As an example, the barrier layer stack including the at least four layers and the substrate may have a transmittance in the range of 87 to 95%, specifically 88% or 89%, and more specifically 93% or 94%.

[0035] As an example, the odd numbered layers can have a refractive index of about at least 1.9, and specifically about 2. The even numbered layers can have a refractive index of less than 1.7, specifically a refractive index of less than 1.5, and particularly of about 1.46. According to some embodiments, the odd numbered layers of the barrier layer stack include at least one of SiNx, NbOx, SiN, SiOxNy, AlOx, AlOxNy, TiOx TaOx, an organic material such as a polymer material, and/or combinations thereof, and/or the even numbered layers of the barrier layer stack include at least one of SiOx, MgFx, SiOxNy, an organic material such as a polymer material, and/or combinations thereof.

[0036] As an example, the first layer 11, e.g. a first dielectric layer, can have a high refractive index. By successively providing layers with alternating or different refractive indexes, a barrier layer stack that also has antireflection characteristics can be provided. According to some embodiments, which can be combined with other embodiments described herein, layers having the lower refractive indexes (e.g. the even numbered layers) can be provided by layers containing SiOx, MgFx, SiOxNy, an organic material such as a polymer material, and/or combinations thereof, or the like. For example, layers having the higher refractive indexes (e.g. the odd numbered layers) can be provided by films containing NbOx, SiNx, SiN, SiOxNy, AlOx, AlOxNy, TiOx TaOx, an organic material such as a polymer material, and/or combinations thereof, or the like.

[0037] According to some implementations, the layers (e.g., dielectric films) can be manufactured by chemical vapor deposition or physical vapor deposition, for example sputtering or evaporation. Some examples can be insulating materials with high and low refractive indexes, for example SiOx, SiN, TiOx, NbOx, SiNx, SiOxNy, AlOx, AlOxNy, TaOx, an organic material such as a polymer material, and/or combinations thereof.

[0038] According to some embodiments, which can be combined with other embodiments herein, at least one of the layers has a thickness of more than 100 nm. As an example, the thickness of each of the odd numbered layers is less than the thickness of each of the even numbered layers.

[0039] In some embodiments, a barrier layer stack having four layers is provided, as it is for instance shown in figure 1A. The first layer 11 may have a thickness of 139 nm to 143 nm, e.g. about 141 nm, the second layer 12 may have a thickness of 169 nm to 173 nm, e.g. about 171, the third layer 13 may have a thickness of 92 nm to 96 nm, e.g. about 94 nm, and the fourth layer 14 may have a thickness of 76 nm to 80 nm, e.g. about 78 nm. In some implementations, the first layer 11 and the third layer 13 may include or be made of SiNx, and the second layer 12 and the fourth layer 14 may include or be made of Si0₂. A water vapor transmission rate (WVTR) of the barrier layer stack can be less than 10^"5, and specifically about 10^~6. A transmittance of the barrier layer stack can be about 94%, particularly in a wavelength range of about 400nm to 700nm.

[0040] In some embodiments, a barrier layer stack having five layers is provided, as it is for instance shown in figure IB. The first layer 11 may have a thickness of 138 nm to 142 nm, e.g. about 140 nm, the second layer 12 may have a thickness of 163 nm to 167 nm, e.g. about 165 nm, the third layer 13 may have a thickness of 120 nm to 124 nm, e.g. about 122 nm, the fourth layer 14 may have a thickness of 155 nm to 159 nm, e.g. about 157 nm, and the fifth layer 15 may have a thickness of 114 nm to 118 nm, e.g. about 116 nm. In some implementations, the first layer 11, the third layer 13 and the fifth layer 15 may include or be made of SiNx, and the second layer 12 and the fourth layer 14 may include or be made of Si0₂. A water vapor transmission rate (WVTR) of the barrier layer stack can be less than 10^"5, and specifically about 10^"6. A transmittance of the barrier layer stack can be about 88%, particularly in a wavelength range of about 400 nm to 700 nm.

[0041] In other implementations, the first layer 11 may have a thickness of 140 nm to 144 nm, e.g. about 142 nm, the second layer 12 may have a thickness of 169 nm to 173 nm, e.g. about 171 nm, the third layer 13 may have a thickness of 126 nm to 130 nm, e.g. about 128 nm, the fourth layer 14 may have a thickness of 160 nm to 164 nm, e.g. about 162 nm, and the fifth layer 15 may have a thickness of 137 nm to 141 nm, e.g. about 139 nm. In some implementations, the first layer 11, the third layer 13 and the fifth layer 15 may include or be made of SiNx, and the second layer 12 and the fourth layer 14 may include or be made of Si0₂. A water vapor transmission rate (WVTR) of the barrier layer stack can be less than 10^"5, and specifically about 10^"6. A transmittance of the barrier layer stack can be in the range of about 88% to about 92%, particularly in a wavelength range of about 400 nm to 700 nm.

[0042] In some embodiments, a barrier layer stack having six layers is provided, as it is for instance shown in figure 1C. The first layer 11 may have a thickness of 137 nm to 141 nm, e.g. about 139 nm, the second layer 12 may have a thickness of 160 nm to 164 nm, e.g. about 162 nm, the third layer 13 may have a thickness of 114 nm to 118 nm, e.g. about 116 nm, the fourth layer 14 may have a thickness of 154 nm to 158 nm, e.g. about 156 nm, the fifth layer 15 may have a thickness of 85 nm to 89 nm, e.g. about 87 nm, and the sixth layer 16 may have a thickness of 75 nm to 79 nm, e.g. about 77 nm. In some implementations, the first layer 11, the third layer 13 and the fifth layer 15 may include or be made of SiNx, and the second layer 12, the fourth layer 14 and the sixth layer 16 may include or be made of Si0₂. A water vapor transmission rate (WVTR) of the barrier layer stack can be less than 10^~5, and specifically about 10^~6. A transmittance of the barrier layer stack can be about 94%, particularly in a wavelength range of about 400nm to 700nm.

[0043] According to some embodiments, which can be combined with other embodiments herein, the layers are formed or arranged over each other. In the examples of figures 1A-C, the second layer 12 is formed or arranged over the first layer 11, the third layer 13 is formed or arranged over the second layer 12 and the fourth layer 14 is formed or arranged over the third layer 13.

[0044] As an example, when reference is made to the term "over", i.e. one layer being over the other, it is understood that, starting from the first layer 11, the second layer 12 is deposited over the first layer 11, and a further layer, deposited after the second layer 12, is thus over the second layer 12 and over the first layer 11. In other words, the term "over" is used to define an order of layers, layer stacks, and/or films wherein the starting point is the substrate. This is irrespective of whether the barrier layer stack is depicted upside down or not.

[0045] According to some embodiments, which can be combined with other embodiments herein, at least some of the layers 11- 14 are directly disposed on each other. In the example of figure 1A, the second layer 12 is formed or arranged on the first layer 11, the third layer 13 is formed or arranged on the second layer 12 and the fourth layer 14 is formed or arranged on the third layer 13. In other words, in some embodiments no further layers or films are present between the layers of the barrier layer stack. In some other embodiments further layers can be provided between at least some of the layers of the barrier layer stack.

[0046] Figure 2 shows a barrier layer stack 40 according to further embodiments described herein.

[0047] According to some embodiments, which can be combined with other embodiments herein, the barrier layer stack 40 further includes a substrate 41, and particularly a transparent substrate. The term "substrate" as used herein can particularly embrace flexible substrates such as a web or a foil. However, the present disclosure is not limited thereto and the term "substrate" may also embrace inflexible substrates, e.g., a wafer, slices of transparent crystal such as sapphire or the like, or a glass plate.

[0048] 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 clearly manner. In some embodiments, which can be combined with other embodiments described herein, the substrate includes a transparent polymer material selected from the group including polycarbonate (PC), polyethylene terephthalate (PET), poly(methacrylic acid methyl ester) (PMMA), triacetyl cellulose (TAC), cyclo olefin polymer (COP), poly(ethylene naphthalate) (PEN), and combinations thereof. As an example, the substrate includes polyethylene terephthalate (PET). PET can have a transmittance of about 90%. For instance, the layers 11-14 are provided on or over the substrate 41.

[0049] Although in figure 2 four layers 11-14 are arranged over the substrate 41, the present embodiments are not limited thereto. Any number of layers can be aixanged over the substrate, as it is for instance described above with reference to figures 1A-C. [0050] According to an aspect of the present embodiments an ultra high barrier (UHB) layer and antireflection system is provided. The ultra high barrier (UHB) layer and antireflection system includes a substrate and a layer stack over or on the substrate. The layer stack may be anyone of the barrier layer stacks described above with reference to figures 1A-C and 2.

The layer stack may particularly include a first layer, a second layer, a third layer and a fourth layer arranged in this order, wherein the first layer and the third layer have a refractive index of at least 1.9, wherein the second layer and the fourth layer have a refractive index of less than 1.7, and wherein each of the layers has a thickness of at least 70 nm.

[0051] Figure 3 shows a graph of a reflectance of barrier layer stacks according to embodiments described herein. The term "reflectance" as used herein is the fraction of incident electromagnetic power that is reflected. The term "reflectance" may be synonymously used with the term "reflectivity".

[0052] In figure 3 the y-axis of the graph denotes a reflectance in % (percent), and the x-axis denotes a wavelength λ (lambda) in units of nanometer (nm). Denoted with reference numeral 50 is a reflectance of an uncoated PET substrate (about 5%). Denoted with reference numeral 51 is a reflectance of a barrier layer stack according to embodiments described herein with four layers (NONO), which is less than 1 percent in a range from about 420 nm to about 680 nm. Reference numeral 52 indicates a reflectance of a barrier layer stack according to embodiments described herein with six layers (NONONO), which is also less than 1 percent in a range from about 420 nm to about 680 nm.

[0053] Methods for depositing a material for instance on a substrate may include a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, a plasma enhanced chemical vapor deposition (PECVD) process etc. As an example, the process is performed in a process apparatus or process chamber, where the substrate to be coated is located. A deposition material is provided in the apparatus. A plurality of materials such as oxides, nitrides or carbides thereof may be used for deposition. Further, other processing steps like etching, structuring, annealing, or the like can be conducted in processing chambers.

[0054] Figure 4 shows a schematic view of an apparatus 100, e.g. a roll- to-roll deposition apparatus, for depositing or coating the layers according to embodiments described herein, and particularly for manufacturing a barrier layer stack according to embodiments described herein.

[0055] The apparatus 100 can include at least three chamber portions 102A, 102B and 102C. At chamber portion 102C one or more deposition sources 630 and optionally an etching station 430 can be provided as processing tools. A substrate 41, e.g. a flexible substrate, is provided on a first roll 764, e.g. having a winding shaft. The flexible substrate is unwound from the roll 764 as indicated by the substrate movement direction shown by arrow 108. A separation wall 401 is provided for separation of chamber portions 102A and 102B. The separation wall 401 can further be provided with gap sluices 140 for having the substrate 41 pass therethrough. A vacuum flange 112 provided between the chamber portions 102B and 102C can be provided with openings to take up at last some processing tools.

[0056] The substrate 41 is moved through the deposition areas provided at a coating drum 110 and corresponding to positions of the deposition sources 630. During operation, the coating drum 110 rotates around an axis such that the substrate 41 moves in direction of arrow 108. According to some embodiments, the substrate 41 is guided via one, two or more rollers from the roll 764 to the coating drum 110 and from the coating drum 110 to the second roll 764', e.g. having a winding shaft, on which the substrate 41 is wound after processing thereof.

[0057] According to some embodiments, the deposition sources 630 can be configured for depositing the layers of the layer stack. As an example, at least one deposition source 630 can be adapted for deposition of the layer material having the refractive index of at least 1.9, and at least one deposition source 630 can be adapted for deposition of the layer material having the refractive index of less than 1.7.

[0058] In some implementations, a first deposition source can be configured for depositing the first layer, a second deposition source can be configured for depositing the second layer, a third deposition source can be configured for depositing the third layer, and a fourth deposition source can be configured for depositing the fourth layer.

[0059] In some implementations, the first chamber portion 102A is separated in an interleaf chamber portion unit 102A1 and a substrate chamber portion unit 102A2. Thereby, interleaf rolls 766/766' and interleaf rollers 105 can be provided as a modular element of the apparatus 100. The apparatus 100 can further include a pre-heating unit 194 to heat the flexible substrate. Further, additionally or alternatively a pre-treatment plasma source 192, e.g. an RF (radio frequency) plasma source can be provided to treat the substrate with a plasma prior to entering chamber portion 102C.

[0060] 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.

[0061] 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 630 may be silicon. As an example, oxide-, nitride- or carbide- layers, which can include such materials, can be deposited by providing the material from the source or by reactive deposition, i.e. the material from the source reacts with elements like oxygen, nitride, or carbon from a processing gas. [0062] According to an aspect of the present disclosure and as shown in figure 4, a method 700 for manufacturing a barrier layer stack is provided. The method may include alternately depositing a first layer material and a second layer material on a substrate to form at least four layers. The first layer material has a refractive index of at least 1.9, the second layer material has a refractive index of less than 1.7, and each of the layers has a thickness of at least 70 nm. A first layer may be deposited for instance on a substrate (block 701). Then, a second layer may be deposited on or over the first layer (block 702). Afterwards a third layer may be deposited on or over the second layer (block 703). A fourth layer may be deposited on or over the third layer (block 704).

[0063] Although in the present example of figure 4 four layers are arranged over each other, the present embodiments are not limited thereto. Any number of layers can be arranged, as it is for instance described above with reference to figures 1A-C and 2.

[0064] 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.

Claims

1. Barrier layer stack, comprising: a first layer, a second layer, a third layer and a fourth layer arranged in this order, wherein the first layer and the third layer have a refractive index of at least 1.9, wherein the second layer and the fourth layer have a refractive index of less than 1.7, and wherein each of the layers has a thickness of at least 70 nm.

2. Barrier layer stack of claim 1, further comprising one or more further layers over the fourth layer, particularly a fifth or a fifth and a sixth layer.

3. Barrier layer stack of claim 1 or 2, wherein the layers are directly disposed on each other.

4. Barrier layer stack of one of claims 1 to 3, wherein odd numbered layers have the refractive index of at least 1.9, and wherein even numbered layers have the refractive index of less than 1.7.

5. Barrier layer stack of one of claims 1 to 4, wherein the odd numbered layers have a refractive index of about 2.

6. Barrier layer stack of one of claims 1 to 5, wherein the even numbered layers have a refractive index of less than 1.6., and particularly of about 1.46.

7. Barrier layer stack of one of claims 1 to 4, wherein odd numbered layers of the barrier layer stack include at least one of SiNx, NbOx, SiN, SiOxNy, AlOx, AlOxNy, TiOx TaOx, an organic material, particularly a polymer material, and combinations thereof, and/or wherein even numbered layers of the barrier layer stack include at least one of SiOx, MgFx, SiOxNy, an organic material, particularly a polymer material, and combinations thereof.

8. Barrier layer stack of one of claims 1 to 7, wherein at least one of the layers has a thickness of more than 100 nm, and particularly has a thickness in the range of 100 to 300 nm.

9. Barrier layer stack of one of claims 1 to 8, wherein the thickness of each of the odd numbered layers is less than the thickness of each of the even numbered layers.

10. Barrier layer stack of one of claims 1 to 9, wherein a water vapor transmission rate of the barrier layer stack is less than 10^"4, particularly less than 10^"5 and specifically about 10^"6.

11. Barrier layer stack of one of claims 1 to 10, wherein a transmittance of the barrier layer stack is at least 85%, and particularly more than 90%.

12. Barrier layer stack of one of claims 1 to 11 , further including a substrate, wherein the layers are provided over the substrate.

13. Barrier layer stack of claim 12, wherein the substrate includes a transparent polymer material selected from the group including polycarbonate, polyethylene terephthalate, poly(mefhacrylic acid methyl ester), triacetyl cellulose, cyclo olefin polymer, poly(ethylene naphthalate), and combinations thereof.

14. Method for manufacturing a barrier layer stack, comprising alternately depositing a first layer material and a second layer material on a substrate to form at least four layers, wherein the first layer material has a refractive index of at least 1.9, wherein the second layer material has a refractive index of less than 1.7, and wherein each of the layers has a thickness of at least 70 nm.

15. Ultra high barrier layer and antireflection system, comprising: a substrate, and a layer stack over the substrate, wherein the layer stack comprises: a first layer, a second layer, a third layer and a fourth layer arranged in this order, wherein the first layer and the third layer have a refractive index of at least 1.9, wherein the second layer and the fourth layer have a refractive index of less than 1.7, and wherein each of the layers has a thickness of at least 70 nm.