WO2008122292A1 - Diffusion-barrier coating for protection of moisture and oxygen sensitive devices - Google Patents

Diffusion-barrier coating for protection of moisture and oxygen sensitive devices Download PDF

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Publication number
WO2008122292A1
WO2008122292A1 PCT/EP2007/003021 EP2007003021W WO2008122292A1 WO 2008122292 A1 WO2008122292 A1 WO 2008122292A1 EP 2007003021 W EP2007003021 W EP 2007003021W WO 2008122292 A1 WO2008122292 A1 WO 2008122292A1
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Prior art keywords
barrier film
coating
layer
oxygen
encapsulation
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PCT/EP2007/003021
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French (fr)
Inventor
Yves Leterrier
Bandeep Singh
Jérôme BOUCHET
Jan-Anders Manson
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Ecole Polytechnique Federale De Lausanne (Epfl)
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Priority to PCT/EP2007/003021 priority Critical patent/WO2008122292A1/en
Publication of WO2008122292A1 publication Critical patent/WO2008122292A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
    • H01L23/291—Oxides or nitrides or carbides, e.g. ceramics, glass
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
    • H01L23/293—Organic, e.g. plastic
    • H01L23/296—Organo-silicon compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
    • H01L23/3157—Partial encapsulation or coating
    • H01L23/3192—Multilayer coating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/12—Passive devices, e.g. 2 terminal devices
    • H01L2924/1204—Optical Diode
    • H01L2924/12044—OLED

Definitions

  • the present invention relates to a diffusion barrier coating for protection of moisture and oxygen sensitive devices such as organic light emitting displays and thin film solar cells.
  • the invention also relates to a method of manufacturing such a barrier coating.
  • the residual permeation of the coated polymer film is attributed to process-induced defects such as pin-holes and microcracks [3], which in addition limit the toughness and achievable flexibility of the package [4-7].
  • the strain to failure of such thin coatings is usually less than 2%, which can be greatly reduced depending on the residual stress state within the layered structure.
  • a specific object of the invention is to provide a coating for encapsulation of devices, having a vapour deposited layer of an inorganic silicon oxide (SiOx or SiOxCy) applied onto a polymer base substrate, having improved oxygen and water vapour barrier properties as well as improved toughness and flexibility.
  • SiOx or SiOxCy inorganic silicon oxide
  • Another specific object of the invention is to provide a coating for encapsulation of devices, having a vapour deposited layer of aluminium oxide (AIOx) applied onto a polymer base substrate, having improved oxygen and water vapour barrier properties as well as improved toughness and flexibility.
  • AIOx aluminium oxide
  • Another specific object of the invention is to provide a coating for encapsulation of devices, having a vapour deposited layer of silicon nitride (SiNx) or silicon oxynitride (SiOxNy) applied onto a polymer base substrate, having improved oxygen and water vapour barrier properties as well as improved toughness and flexibility.
  • SiNx silicon nitride
  • SiOxNy silicon oxynitride
  • a further object of the invention is to provide a flexible multilayer polymer composite film for long-term protection of oxygen and moisture sensitive devices, including a barrier film comprising a vapour deposited coating of an inorganic material applied onto a polymer base substrate, having improved barrier properties and improved toughness and flexibility.
  • Yet a further object of the invention is to provide a multilayer polymer composite film for long-term protection of oxygen and moisture sensitive devices, including a barrier film comprising a vapour deposited coating of an inorganic material applied onto a polymer base substrate, having improved barrier properties, toughness and flexibility, as well as improved device integrity by the improved adhesion between the inorganic coating and an adjacent polymer layer.
  • the invention is also directed to the encapsulation of devices such as a flexible optoelectronic devices and flexible photovoltaic modules, produced using a multilayer polymer composite film comprising the barrier coating.
  • the invention is directed to a method for manufacturing of the improved barrier coating of the invention.
  • a further layer onto the vapour deposited coating comprising an inorganic material, which layer is consisting of a crosslinked organo-polysiloxane, which is covalently bound to the inorganic coating and functions as a healing layer.
  • Such a crosslinked healing layer has particularly positive effects on the toughness, flexibility and barrier properties of vapour deposited silicon oxide coatings, but positive effects are expected for any inorganic oxide having similar chemistry to silicon oxides, such as for example aluminium oxides, magnesium oxides, titanium oxides and other metal oxides. Positive effects will also be achieved regarding the toughness and barrier properties of other inorganic coatings, insofar as the surface e of the inorganic coating is hydrated and comprises OH groups.
  • the inorganic coatings are applied by means of physical vapour deposition (PVD) or reactive vapour deposition and, more preferably, by plasma enhanced chemical vapour deposition (PECVD). This type of coatings provide gas barrier properties to the coated polymer film as well as some degree of water vapour barrier properties, and are transparent coatings, which may be preferred in some cases.
  • An especially preferred silicon oxide coating has the formula SiOxCy 1 wherein carbon is covalently bound in the formula and x varies between 0,1 and 2,5, and y may vary between 0,1 and 2,5.
  • Such carbon-containing coatings have improved water vapour barrier in addition to gas barrier properties.
  • Another preferred coating is a silicon oxide coating of the formula SiO x CyN 2 , wherein the carbon atoms and the nitrogen atoms are covalently bound and x is from 0.1 to 2.5, y is from 0.1 to 2.5 and z is from 0.1 to 2.5.
  • Another preferred coating is a silicon nitride coating of the formula SiN x , wherein x is from 1 to 2.
  • a sole coating of SiO x C y N z has a thickness of from 5 to 100 nm and is deposited by PECVD using a process gas mixture comprising an organosilicon compound and nitrogen as the carrier gas.
  • the thin vapour deposited inorganic-oxide comprising layers according to the invention are nanometer-thick, i.e. they have a thickness that is most suitably counted in nanometers, for example of from 5 to 500 nm, preferably from 5 to 200 nm, and more preferably from 5-100 nm.
  • a further preferable coating is a coating of aluminium oxide having the formula AIOx wherein x varies from 1.0 to 1.5, preferably of AI 2 O 3 .
  • the thickness of such a coating is from 5 to 100 nm, preferably from 5 to 30 nm.
  • Deposition by a plasma enhanced chemical vapour deposition method is preferred for the deposition of inorganic oxide and nitride coatings, because of cost advantages and the advantageous barrier and flexibility qualities obtained of the coating, but also other vapour deposition methods, i.e. any reactive evaporation or electron beam reactive evaporation method or any heat evaporation method. These methods are normally batch-wise processes, requiring a reaction chamber with under-pressure or vacuum for the reactive evaporation operation.
  • deposition by an atmospheric plasma method is also advantageous and desirable because it is a continuous coating method, enabling easier control and logistics of the production of coated film.
  • Another, such continuous and highly desirable vapour deposition coating method is the so-called flame coating or combustion chemical vapour deposition (CCVD) method.
  • the polymer base substrate comprises a layer for receiving the vapour deposited material, which layer is made of a material suitable for receiving the functional layer with good adhesion and coating quality.
  • the material is a thermoplastic polymer material having a glass transition temperature (Tg) higher than or equal to - 10 0 C.
  • Tg glass transition temperature
  • Such polymer materials are generally more suitable for substrate layers for heat-generating coating operations, because they have other melt behaviour characteristics than, on the other hand polyethylene, for example.
  • high-Tg polymer materials are selected from the group that consists of polyamide (PA), polyamide copolymer, polyester, and polyester copolymer.
  • PET polyethylene terephthalate
  • PET-X copolymers
  • PET-G polyethylene terephthalate modified with glycol units
  • PBT polybutylene terephthalate
  • PEN polyethylene naphthalate
  • very high-Tg polymers are selected from the group of amorphous polymers that consists in polyimides (Pl), polyethersulfones (PES) and aromatic polyesters. These polymers all have Tg ' s above room temperature.
  • polypropylene is a polymer having the required Tg, i.e. a Tg of just about -10 0 C.
  • the base film or layer is made of polyethyleneterephthalate (PET) or polyamide (PA) 1 and most preferably of polyamide, because polyamides provide a smooth surface for receiving a coating of a polymer or composition of the functional layer and, therefore, improves the quality and properties of the applied functional layer.
  • PET polyethyleneterephthalate
  • PA polyamide
  • a preferred polymer base substrate is made of polyethylenenaphthalate (PEN).
  • the high Tg polymers such as Pl and PES are preferred materials.
  • the thickness of the polymer base substrate is less important for the quality of the functional layer and as long as the surface of the substrate layer is smooth and well suited for coating, the thickness of the substrate layer is less important. Practical requirements on the base film thickness may provide a lower thickness limit at about 2 ⁇ m, which is easily accessible for solution processed polymers such as polyimides, and an upper limit of about 300 ⁇ m appears reasonable, for cost reasons.
  • the healing layer is thus a crosslinked reaction product from a composition consisting essentially of unsaturated silanes having three silanol-forming groups. It is important for the inventive results that the composition consists of essentially only unsaturated silanes and possibly only minor amounts of a similar saturated silane compound. Such minor amounts should constitute less than 5 weight-% of the total of the silane compounds of the composition, preferably less than 3 weight-%. A minor amount of unsaturated silanes having only two silanol-forming groups may be present in the composition, but should constitute less than 5 weight-%, preferably less than 3 weight-%. The content of silanes other than unsaturated silanes having three silanol-forming groups should be less than 10-weight % of the total silane coating composition.
  • the unsaturated, reactive silane having three silanol-forming groups may generally be represented by the formula R-Si-X 3 , where R is a radical which contains a functional group capable of undergoing free radical polymerisation and X is a hydrolysable radical.
  • R is a radical which contains a functional group capable of undergoing free radical polymerisation
  • X is a hydrolysable radical.
  • Representative R substituents may include gammamethacryloxypropyl, gammaacryloxypropyl, vinyl or allyl.
  • Representative silanol-forming X substituents may include acetoxy and alkoxy having 1- to 8 carbons such as for example methoxy, ethoxy, isobutoxy, methoxymethoxy, ethoxymethoxy and ethoxyphenoxy.
  • the reactive silanes employed are selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, butenyltrimethoxysilane, butenyltriethoxysilane, gamma- metacryloxypropyltriethoxysilane, gamma-metacryloxypropyltrimethoxysilane, gamma-acryloxypropyltriethoxysilane, gamma-acryloxypropyltrimethoxysilane, vinyltriacetoxysilane and mixtures thereof.
  • the most preferred reactive silane is selected from the group consisting of vinyltrimethoxysilane and vinyltriethoxysilane.
  • the thickness of the crosslinked polyorganosiloxane is within the range of 1 to 50 nm, preferably 1-30 nm, more preferably 10-30 nm.
  • the barrier film as described above is useful in multilayer flexible polymer composite encapsulation for long-term protection of oxygen and moisture sensitive devices.
  • the barrier film of the invention is manufactured by a method comprising the steps of providing a base film of a polymer, applying onto the base film a barrier coating comprising an inorganic coating by means of a vapour deposition method and further coating said vapour deposited inorganic coating, wherein the further coating step comprises the steps of providing a composition consisting essentially of a reactive unsaturated silane compound having three silanol-forming groups dissolved in a solvent, coating the composition onto the inorganic vapour deposited coating, subjecting the coated composition to hydrolysis and condensation reaction to provide an ethylenically unsaturated organosiloxane oligomer, which is covalently bound to the inorganic coating and, finally, curing the coated organosiloxane oligomer to provide the crosslinked polysiloxane layer.
  • the reactive silane layer composition is applied as a liquid film on top of the inorganic coating by means of any suitable liquid film coating method, as a solution of from 1 to 10, preferably from 2 to 6 weight-% more preferably from 3 to 6 weight-% of the reactive silane in ethanol.
  • the coating solution is applied by means of a transfer roller, which is dipped into the solution and rolled onto the inorganic coating.
  • An alternative is to apply the silane layer using a spin-coating method.
  • the silane composition penetrates down into the micrometer- and nanometer-sized cracks and pinholes of the inorganic coating, whereafter the composition is hydrolysed and further subjected to condensation reaction such that the silanol-forming groups are partly condensed within the organosilane composition layer into an organosiloxane oligomer, as well as partly condensed with hydroxyl groups formed on the surface of the inorganic coating.
  • the organosiloxane oligomer is crosslinked at the sites of carbon-to-carbon unsaturation, whereby a crosslinked polyorganosiloxane layer is obtained, which is tightly bound to the inorganic coating by covalent bonds.
  • the thickness of the thus applied reactive silane solution may vary from 1 to 50 nm, preferably from 10 to 30 nm, as measured before condensation and curing.
  • the reaction product at the interface between the inorganic coating and the polyorganosiloxane layer may be referred to as a hybrid material rather than two separate layers.
  • the two materials are reacted with each other by closely situated covalent bonds extending over the whole surface of the barrier film, and there is no longer a distinct interface between the layers. Consequently, the layers are inseparable and will not delaminate or detach from each other at any point within the barrier hybrid layer.
  • the curing step is carried out by crosslinking by means of irradiation energy and according to a preferred embodiment, UV irradiation is employed in combination with the inclusion of a photoinitiator to the healing layer coating composition.
  • concentration of the photoinitiator included in the healing layer coating composition is suitably from 1 to 10 weight-%, preferably from 2 to 5 weight- % more preferably from 3 to 5 weight-%, most preferably from 3 to 4 weight-%.
  • Fig. 1a, 1b and 1c are schematically showing, in cross-section, the steps of the creation of the barrier layer in the barrier film according to the invention
  • Fig. 2 schematically shows an embodiment of a multilayer polymer composite barrier film according to the invention.
  • Fig. 3-6 are graphs showing the relationship between oxygen transmission and nominal strain of the respective tests of hybrid layers described in the Examples.
  • Figure 1 thus shows how the hybrid barrier layer of the invention is created.
  • the defects of the inorganic coating (preferably silicon oxide) layer 11 are shown and at Figure 1 b, the defects are filled with the organosilane monomer/oligomer.
  • the base film 12 which is a polymer film, preferably with a very smooth surface for obtaining optimal barrier properties of the inorganic coating.
  • the organosilane monomer/oligomer condensates with each other and with the inorganic surface hydroxyl/silanol groups and, subsequently, are polymerised by an external source of UV irradiation, to form a crosslinked polyorganosiloxane layer on the inorganic substrate surface.
  • FIG. 1 shows, in cross-section, a first embodiment of a flexible multilayer polymer composite barrier film produced according to the invention.
  • the multilayer structure comprises a base polymer substrate 21 and a hybrid barrier layer 22, which is applied onto the base polymer substrate, and composed of a first vapour deposited inorganic coating 22-1 and a second, covalently bound layer of a cross-linked polyorganosiloxane 22-2.
  • barrier film of the invention may be combined with further layers providing functionality, such as barrier properties or toughness properties or the like, as also electrical properties for use as transparent electrodes.
  • the healing layer coating tests were carried out on films of 12 ⁇ m thick PET coated with a silicon oxide of the general formula SiOx, where in x is from about 1 ,7 to about 2,2, by means of plasma enhanced chemical vapour deposition (PECVD). Two different thickness of the SiOx coating were tested, 50 nm and 10 nm as indicated in Table 1.1.
  • PECVD plasma enhanced chemical vapour deposition
  • the silane and photoinitiators that were tested are reported in Table 1.2.
  • the unsaturated organosilane monomers are MAPS and VS.
  • Two photoinitiators were used, with concentration from 2 to 5 we ⁇ ght-%, so that 4 different silane formulations were tested (2 silanes x 2 photoinitiators).
  • the organosilane with photoinitiator was dissolved to a concentration of from 3 to 6 weight-% in ethanol.
  • the organosilane solution composition was applied as a liquid film on top of the SiOx layer by means of a transfer roller which was dipped into the solution composition and then contacted with the SiOx surface. The thickness of the thus applied coating of organosilane was about 25 nm
  • Table 2.2 OTR data points taken from strained 50-nm thick SiOx layers not treated with organosilane.
  • Table 3 1 summarizes the OTR data for the respective treatments with MAPS-1 , MAPS-2, VS-1 and VS-2 formulations
  • Figure 3 shows semi-log plots of the OTR data as a function of nominal strain This figure shows also the OTR data taken from strained SiOx/PET samples without the organosilane treatment from Table 2 2
  • the effect of the UV-cured organosilane is clearly observable by comparing the COS position of the different samples
  • the non-treated SiOx/PET samples have a COS at 2% nominal strain, whilst MAPS-treated and VS-treated SiOx/PET samples show COS at 3%, 4% and beyond 5% depending on the photo-initiator compounds, PI-1 or PI-2, mixed in the solution
  • Table 3 1 OTR points taken from strained SiOx layers 50 nm thick treated with MAPS-1, MAPS-2, VS-1 and VS-2 healing formulations
  • Figure 3 shows semi-log plots of OTR data taken during straining of 50 nm thick SiOx barrier coatings deposited on PET 12 mm films by PECVD
  • the graph shows the OTR behaviour for non-treated SiOx/PET samples and SiOx/PET samples treated with the organosilane formulations MAPS-1 , MAPS-2, VS-1 and VS-2
  • Figure 4 shows the semi-log plots of the OTR data taken from strained SiOx 50 nm thick barrier coatings deposited on PET 12 mm films by PECVD.
  • the graph shows the OTR behaviour of the eight SiOx/PET samples treated with the VS-2 organosilane formulation It shows also the behaviour of non-treated SiOx/PET samples as a function of nominal strain.
  • Figure 4 shows the typical behaviour of healed samples where the OTR is constant below the critical strain (COS) and increases dramatically beyond this point. Out of the eight samples, seven have a COS at 5 %, whilst 6% is reached by one sample. For the non-treated 50-nm thick SiOx layers, the behaviour is much different from the organosilane-modified samples: the COS is localized around 2% nominal strain and the OTR 1 at 5%, reaches 100-cm 3 /m 2 /day/bar.
  • COS critical strain
  • Figure 5 shows the OTR data taken from strained 50 nm thick SiOx barrier coatings deposited on PET 12-mm films by PECVD.
  • the graph shows the average OTR data from the eight SiOx/PET samples treated with the VS-2 organosilane formulation and the behaviour of the 3 non-treated SiOx/PET samples of Table 2.2
  • Figure 6 shows OTR data taken from strained 10 nm thick SiOx barrier coatings deposited on PET 12- ⁇ m films by PECVD.
  • the graph shows the average OTR from the three SiOx/PET samples treated with the VS-2 organosilane formulation of Table 3.3 and the behaviour of the non-treated SiOx/PET samples of Table 2.1
  • the oxygen barrier of the treated samples increase with the formation of the polysiloxane hybrid and the corresponding COS is between 5 and 6% nominal strain.
  • the improvement is less drastic than for the thicker SiOx layers.
  • One other feature of SiOx oxide barriers is the COS position dependence on the SiOx thickness. This dependence is clearly seen when looking at the COS positions of non-treated samples of 10 nm and 50 nm thickness, respectively.
  • the COS of the 10 nm thick SiOx layers is positioned at 4%, whilst at 2% only for 50 nm thick SiOx layers (Fig. 3 and 6). This difference might explain why the healing effect of the crosslinked organosilane is less active with the thinner SiOx layer.
  • the 50 nm and 10 nm un-coated not organosilane-healed SiOx/PET samples have COS at 2% and 4%, respectively.
  • the 3% Vinylsilane-coated 50 nm and 10 nm SiOx/PET samples have COS at 6% and 5.5% respectively.
  • Rochat, G. Leterrier, Y., Plummer, C. J. G., et al., J. Appl. Phys., 95, 5429-5434 (2004).
  • Rochat G. Delachaux A., Leterrier Y., et al., Surf. Interf. Anal., 35, 948-952 (2003).

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Abstract

Barrier film for encapsulation of oxygen and moisture sensitive devices comprising a base polymer substrate and applied onto the base substrate, a barrier layer comprising an inorganic coating deposited by a vapour deposition method, characterised in that the deposited barrier coating is further coated with a healing layer consisting of a crosslinked organopolysiloxane, which is covalently bound to the inorganic coating.

Description

DIFFUSION-BARRIER COATING FOR PROTECTION OF MOISTURE AND
OXYGEN SENSITIVE DEVICES
TECHNICAL FIELD
The present invention relates to a diffusion barrier coating for protection of moisture and oxygen sensitive devices such as organic light emitting displays and thin film solar cells. The invention also relates to a method of manufacturing such a barrier coating.
STATE OR THE ART
Lifetime stability of emerging organic opto-electronic devices is a major concern, due to the sensitivity of their constituents to moisture and oxygen, and hermetic encapsulation of the device is mandatory [1]. Glass has been systematically used for decades as the only transparent encapsulation material. In recent years however, a broad diversity of transparent inorganic materials have been proposed in the prior art as gas-barrier coatings deposited on polymer films against oxygen and/or water vapour, including oxides and nitrides (for example SiOx, SiOxCy, AIOx, SiNx, SiOxNy) [2] as alternatives to heavy and brittle glass. Single coatings enable a two- to three-orders of magnitude improvement of the barrier properties of uncoated polymer films. The residual permeation of the coated polymer film is attributed to process-induced defects such as pin-holes and microcracks [3], which in addition limit the toughness and achievable flexibility of the package [4-7]. The strain to failure of such thin coatings is usually less than 2%, which can be greatly reduced depending on the residual stress state within the layered structure.
Various methods have been identified to further improve the barrier performance of these ceramic/polymer films, such as alternate organic/inorganic coating layers, multiple ceramic coatings etc. Recent developments include layered stacks, where the defect structure of the individual inorganic layers is decoupled [8] using intermediate non-conformal organic layers [9], and inorganic coatings with composition gradient, such as silicon oxide-silicon nitride. These nano-composite materials are very effective to stop the diffusion of small molecules and, therefore, enable remarkable barrier performance. However, their mechanical integrity is often reduced compared to single coatings, with increasing risk of interfacial delamination, as also as a result of uncontrolled residual stress states. This is because of the multiple-step production of these multilayer coatings resulting in complex internal stress states, especially at interfaces. The consequence is an increased risk of premature mechanical failure such as cracking and delamination, during both manufacturing and service life. There is thus a need to improve the durability and flexibility of such vapour deposited inorganic layers and also their barrier properties.
DISCLOSURE OF THE INVENTION
It is, therefore, an object of the present invention to overcome the above-described problems.
It is a general object of the invention to provide a coating for encapsulation of devices, having a vapour deposited layer comprising an inorganic coating applied onto a polymer base substrate, having improved barrier properties.
It is a further general object of the invention to provide a coating for encapsulation of devices, having a vapour deposited layer comprising an inorganic coating applied onto a polymer base substrate, having improved toughness and flexibility.
A specific object of the invention is to provide a coating for encapsulation of devices, having a vapour deposited layer of an inorganic silicon oxide (SiOx or SiOxCy) applied onto a polymer base substrate, having improved oxygen and water vapour barrier properties as well as improved toughness and flexibility.
Another specific object of the invention is to provide a coating for encapsulation of devices, having a vapour deposited layer of aluminium oxide (AIOx) applied onto a polymer base substrate, having improved oxygen and water vapour barrier properties as well as improved toughness and flexibility.
Another specific object of the invention is to provide a coating for encapsulation of devices, having a vapour deposited layer of silicon nitride (SiNx) or silicon oxynitride (SiOxNy) applied onto a polymer base substrate, having improved oxygen and water vapour barrier properties as well as improved toughness and flexibility.
A further object of the invention is to provide a flexible multilayer polymer composite film for long-term protection of oxygen and moisture sensitive devices, including a barrier film comprising a vapour deposited coating of an inorganic material applied onto a polymer base substrate, having improved barrier properties and improved toughness and flexibility.
Yet a further object of the invention is to provide a multilayer polymer composite film for long-term protection of oxygen and moisture sensitive devices, including a barrier film comprising a vapour deposited coating of an inorganic material applied onto a polymer base substrate, having improved barrier properties, toughness and flexibility, as well as improved device integrity by the improved adhesion between the inorganic coating and an adjacent polymer layer.
The invention is also directed to the encapsulation of devices such as a flexible optoelectronic devices and flexible photovoltaic modules, produced using a multilayer polymer composite film comprising the barrier coating.
In addition, the invention is directed to a method for manufacturing of the improved barrier coating of the invention.
These objects are attained according to the present invention by the barrier coating, the flexible multilayer polymer composite film for encapsulation of devices and the method as defined in the appended claims.
These objects are thus attained according to the present invention by a further layer onto the vapour deposited coating comprising an inorganic material, which layer is consisting of a crosslinked organo-polysiloxane, which is covalently bound to the inorganic coating and functions as a healing layer.
Such a crosslinked healing layer has particularly positive effects on the toughness, flexibility and barrier properties of vapour deposited silicon oxide coatings, but positive effects are expected for any inorganic oxide having similar chemistry to silicon oxides, such as for example aluminium oxides, magnesium oxides, titanium oxides and other metal oxides. Positive effects will also be achieved regarding the toughness and barrier properties of other inorganic coatings, insofar as the surface e of the inorganic coating is hydrated and comprises OH groups. Preferably, the inorganic coatings are applied by means of physical vapour deposition (PVD) or reactive vapour deposition and, more preferably, by plasma enhanced chemical vapour deposition (PECVD). This type of coatings provide gas barrier properties to the coated polymer film as well as some degree of water vapour barrier properties, and are transparent coatings, which may be preferred in some cases.
An especially preferred silicon oxide coating has the formula SiOxCy1 wherein carbon is covalently bound in the formula and x varies between 0,1 and 2,5, and y may vary between 0,1 and 2,5. Such carbon-containing coatings have improved water vapour barrier in addition to gas barrier properties.
Another preferred coating is a silicon oxide coating of the formula SiOxCyN2, wherein the carbon atoms and the nitrogen atoms are covalently bound and x is from 0.1 to 2.5, y is from 0.1 to 2.5 and z is from 0.1 to 2.5.
Another preferred coating is a silicon nitride coating of the formula SiNx, wherein x is from 1 to 2.
Preferably, a sole coating of SiOxCyNz has a thickness of from 5 to 100 nm and is deposited by PECVD using a process gas mixture comprising an organosilicon compound and nitrogen as the carrier gas.
The thin vapour deposited inorganic-oxide comprising layers according to the invention are nanometer-thick, i.e. they have a thickness that is most suitably counted in nanometers, for example of from 5 to 500 nm, preferably from 5 to 200 nm, and more preferably from 5-100 nm.
A further preferable coating is a coating of aluminium oxide having the formula AIOx wherein x varies from 1.0 to 1.5, preferably of AI2O3. Preferably, the thickness of such a coating is from 5 to 100 nm, preferably from 5 to 30 nm.
Deposition by a plasma enhanced chemical vapour deposition method (PECVD) is preferred for the deposition of inorganic oxide and nitride coatings, because of cost advantages and the advantageous barrier and flexibility qualities obtained of the coating, but also other vapour deposition methods, i.e. any reactive evaporation or electron beam reactive evaporation method or any heat evaporation method. These methods are normally batch-wise processes, requiring a reaction chamber with under-pressure or vacuum for the reactive evaporation operation. On the other hand, deposition by an atmospheric plasma method is also advantageous and desirable because it is a continuous coating method, enabling easier control and logistics of the production of coated film. Another, such continuous and highly desirable vapour deposition coating method is the so-called flame coating or combustion chemical vapour deposition (CCVD) method.
The polymer base substrate comprises a layer for receiving the vapour deposited material, which layer is made of a material suitable for receiving the functional layer with good adhesion and coating quality. Suitably the material is a thermoplastic polymer material having a glass transition temperature (Tg) higher than or equal to - 10 0C. Such polymer materials are generally more suitable for substrate layers for heat-generating coating operations, because they have other melt behaviour characteristics than, on the other hand polyethylene, for example. Examples of such high-Tg polymer materials are selected from the group that consists of polyamide (PA), polyamide copolymer, polyester, and polyester copolymer. Examples are polyethylene terephthalate (PET) and copolymers (PET-X), such as for example polyethylene terephthalate modified with glycol units (PET-G), polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN). Further examples of very high-Tg polymers are selected from the group of amorphous polymers that consists in polyimides (Pl), polyethersulfones (PES) and aromatic polyesters. These polymers all have Tg 's above room temperature. Also polypropylene is a polymer having the required Tg, i.e. a Tg of just about -100C. Further examples are found in the group of polyvinylidene fluoride (PVDF) and other fluoropolymers such as polytetrafluoroethylene (PTFE) and copolymers such as copolymers of ethylene and tetrafluoroethylene (ETFE). Preferably, for those devices that do not require process temperatures above 1000C, the base film or layer is made of polyethyleneterephthalate (PET) or polyamide (PA)1 and most preferably of polyamide, because polyamides provide a smooth surface for receiving a coating of a polymer or composition of the functional layer and, therefore, improves the quality and properties of the applied functional layer. For more demanding temperature requirements, a preferred polymer base substrate is made of polyethylenenaphthalate (PEN). For even more demanding process conditions, where temperature stability of the base substrate must be higher than 2000C, the high Tg polymers such as Pl and PES are preferred materials. The thickness of the polymer base substrate is less important for the quality of the functional layer and as long as the surface of the substrate layer is smooth and well suited for coating, the thickness of the substrate layer is less important. Practical requirements on the base film thickness may provide a lower thickness limit at about 2 μm, which is easily accessible for solution processed polymers such as polyimides, and an upper limit of about 300 μm appears reasonable, for cost reasons.
The healing layer is thus a crosslinked reaction product from a composition consisting essentially of unsaturated silanes having three silanol-forming groups. It is important for the inventive results that the composition consists of essentially only unsaturated silanes and possibly only minor amounts of a similar saturated silane compound. Such minor amounts should constitute less than 5 weight-% of the total of the silane compounds of the composition, preferably less than 3 weight-%. A minor amount of unsaturated silanes having only two silanol-forming groups may be present in the composition, but should constitute less than 5 weight-%, preferably less than 3 weight-%. The content of silanes other than unsaturated silanes having three silanol-forming groups should be less than 10-weight % of the total silane coating composition. The unsaturated, reactive silane having three silanol-forming groups may generally be represented by the formula R-Si-X3, where R is a radical which contains a functional group capable of undergoing free radical polymerisation and X is a hydrolysable radical. Representative R substituents may include gammamethacryloxypropyl, gammaacryloxypropyl, vinyl or allyl. Representative silanol-forming X substituents may include acetoxy and alkoxy having 1- to 8 carbons such as for example methoxy, ethoxy, isobutoxy, methoxymethoxy, ethoxymethoxy and ethoxyphenoxy. Preferably, the reactive silanes employed are selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, butenyltrimethoxysilane, butenyltriethoxysilane, gamma- metacryloxypropyltriethoxysilane, gamma-metacryloxypropyltrimethoxysilane, gamma-acryloxypropyltriethoxysilane, gamma-acryloxypropyltrimethoxysilane, vinyltriacetoxysilane and mixtures thereof. The most preferred reactive silane is selected from the group consisting of vinyltrimethoxysilane and vinyltriethoxysilane.
The thickness of the crosslinked polyorganosiloxane is within the range of 1 to 50 nm, preferably 1-30 nm, more preferably 10-30 nm.
According to a second aspect of the invention, the barrier film as described above is useful in multilayer flexible polymer composite encapsulation for long-term protection of oxygen and moisture sensitive devices.
According to a further aspect of the invention, the barrier film of the invention is manufactured by a method comprising the steps of providing a base film of a polymer, applying onto the base film a barrier coating comprising an inorganic coating by means of a vapour deposition method and further coating said vapour deposited inorganic coating, wherein the further coating step comprises the steps of providing a composition consisting essentially of a reactive unsaturated silane compound having three silanol-forming groups dissolved in a solvent, coating the composition onto the inorganic vapour deposited coating, subjecting the coated composition to hydrolysis and condensation reaction to provide an ethylenically unsaturated organosiloxane oligomer, which is covalently bound to the inorganic coating and, finally, curing the coated organosiloxane oligomer to provide the crosslinked polysiloxane layer. The reactive silane layer composition is applied as a liquid film on top of the inorganic coating by means of any suitable liquid film coating method, as a solution of from 1 to 10, preferably from 2 to 6 weight-% more preferably from 3 to 6 weight-% of the reactive silane in ethanol. Preferably, the coating solution is applied by means of a transfer roller, which is dipped into the solution and rolled onto the inorganic coating. An alternative is to apply the silane layer using a spin-coating method. At application of the layer, the silane composition penetrates down into the micrometer- and nanometer-sized cracks and pinholes of the inorganic coating, whereafter the composition is hydrolysed and further subjected to condensation reaction such that the silanol-forming groups are partly condensed within the organosilane composition layer into an organosiloxane oligomer, as well as partly condensed with hydroxyl groups formed on the surface of the inorganic coating. Subsequently, the organosiloxane oligomer is crosslinked at the sites of carbon-to-carbon unsaturation, whereby a crosslinked polyorganosiloxane layer is obtained, which is tightly bound to the inorganic coating by covalent bonds.
The thickness of the thus applied reactive silane solution may vary from 1 to 50 nm, preferably from 10 to 30 nm, as measured before condensation and curing.
The reaction product at the interface between the inorganic coating and the polyorganosiloxane layer may be referred to as a hybrid material rather than two separate layers. The two materials are reacted with each other by closely situated covalent bonds extending over the whole surface of the barrier film, and there is no longer a distinct interface between the layers. Consequently, the layers are inseparable and will not delaminate or detach from each other at any point within the barrier hybrid layer.
Preferably, the curing step is carried out by crosslinking by means of irradiation energy and according to a preferred embodiment, UV irradiation is employed in combination with the inclusion of a photoinitiator to the healing layer coating composition. The concentration of the photoinitiator included in the healing layer coating composition is suitably from 1 to 10 weight-%, preferably from 2 to 5 weight- % more preferably from 3 to 5 weight-%, most preferably from 3 to 4 weight-%. EXAMPLES AND DESCRIPTION OF PREFERRED EMBODIMENTS
In the following, preferred embodiments of the invention will be described with reference to the drawings, of which:
Fig. 1a, 1b and 1c are schematically showing, in cross-section, the steps of the creation of the barrier layer in the barrier film according to the invention,
Fig. 2 schematically shows an embodiment of a multilayer polymer composite barrier film according to the invention.
Fig. 3-6 are graphs showing the relationship between oxygen transmission and nominal strain of the respective tests of hybrid layers described in the Examples.
Figure 1 thus shows how the hybrid barrier layer of the invention is created. At Figure 1a, the defects of the inorganic coating (preferably silicon oxide) layer 11 are shown and at Figure 1 b, the defects are filled with the organosilane monomer/oligomer. The base film 12, which is a polymer film, preferably with a very smooth surface for obtaining optimal barrier properties of the inorganic coating. After hydrolysis, at Figure 1c, the organosilane monomer/oligomer condensates with each other and with the inorganic surface hydroxyl/silanol groups and, subsequently, are polymerised by an external source of UV irradiation, to form a crosslinked polyorganosiloxane layer on the inorganic substrate surface. Accordingly, gas and vapour permeation linked to defects in the inorganic coating is reduced and, hence, the barrier properties of the hybrid material is increased. In parallel, the toughness of the healed inorganic coating is improved such that the crack onset strain (COS) shifts to a higher level. The COS is the critical strain level at which the oxygen transmission is still unaffected, before it is rapidly increased, due to the increased amount of cracks appearing in the barrier layer. Figure 2 shows, in cross-section, a first embodiment of a flexible multilayer polymer composite barrier film produced according to the invention. The multilayer structure comprises a base polymer substrate 21 and a hybrid barrier layer 22, which is applied onto the base polymer substrate, and composed of a first vapour deposited inorganic coating 22-1 and a second, covalently bound layer of a cross-linked polyorganosiloxane 22-2.
The invention is not limited by the embodiments shown and described above, but may be varied within the scope of the claims. It is for example to be understood that the barrier film of the invention may be combined with further layers providing functionality, such as barrier properties or toughness properties or the like, as also electrical properties for use as transparent electrodes.
Furthermore, it is to be understood that conventional adhesion-promoting surface treatments as well as conventional adhesives and primers may be used in order to secure integrity properties, i.e. adhesion between layers.
EXAMPLES
1. Chemicals and Materials Used
The healing layer coating tests were carried out on films of 12 μm thick PET coated with a silicon oxide of the general formula SiOx, where in x is from about 1 ,7 to about 2,2, by means of plasma enhanced chemical vapour deposition (PECVD). Two different thickness of the SiOx coating were tested, 50 nm and 10 nm as indicated in Table 1.1.
Table 1. 1 SiOx/PET films
Figure imgf000012_0001
The silane and photoinitiators that were tested are reported in Table 1.2. The unsaturated organosilane monomers are MAPS and VS. Two photoinitiators were used, with concentration from 2 to 5 weιght-%, so that 4 different silane formulations were tested (2 silanes x 2 photoinitiators). The organosilane with photoinitiator was dissolved to a concentration of from 3 to 6 weight-% in ethanol. The organosilane solution composition was applied as a liquid film on top of the SiOx layer by means of a transfer roller which was dipped into the solution composition and then contacted with the SiOx surface. The thickness of the thus applied coating of organosilane was about 25 nm
Table 1.2. Silanes and photo Initiators
Name of Manufacturer Structure Properties characte Compound ristics
Gamma- 99% Pure from MoI Weight UV- methacryloxy GE speciality CH3 |? OE. 274 g/mol curable
CH,= = C C -O -(CH3), Si^-OEt propyltπethoxy materials, \
OEt Density silane silane Switzerland 1 045 g cm"1
(MAPS)
Vinyltπmethoxy 99% Pure from MoI Weight UV- silane GE speciality 219 g/mol curable (VS) materials, Density silane
Switzerland 1 12 g/cm3
Phenyl bis > 99% pure Melting point UV-
(2,4,6-tπmethyl Ciba speciality 127-133°C Photo- benzoyl) chemicals, initiator
(PI-1) Switzerland
2-Benzyl-2- > 99% pure MoI Weight UV- dimethylamino- Ciba speciality 366 5 g/mol Photo- 1-(4-morpholιno chemicals, Melting point initiator phenyl)- Switzerland
Figure imgf000013_0001
115 °C butanone-1 dissociates
(PI-2) hetrolytically
2 OTR at traction of non-treated SiOx/PET films Film samples taken from PEVCD SiOx deposition-coated PET films were prepared for oxygen transmission rate (OTR) measurements whilst the samples were submitted to uniaxial straining force. The measurement device consists of a straining apparatus mounted on a Mocon® oxygen diffusion cell. The arrangement allows simultaneous measurement of OTR and of position of the crack onset strain (COS) as function of the uniaxial straining force applied on the samples. At straining beyond the COS critical point, the oxygen gas diffusion through the samples increased by about one order of magnitude because of the fragmentation of the SiOx or organosilane/SiOx layers. OTR data have been taken for each 1.0% step increase of the nominal strain.
The OTR measurements of non-treated samples have been made for 10- and 50-nm thick SiOx layers PECVD deposited onto 12-mm PET films. Table 2.1 and Table 2.2 list the respective OTR measurement points for plain SiOx/PET films without the deposition of the healing organosilane coating.
Table 2.1: OTR data points taken from strained 10-nm thick SiOx layers not treated with organosilane
Figure imgf000014_0001
Table 2.2: OTR data points taken from strained 50-nm thick SiOx layers not treated with organosilane.
Figure imgf000014_0002
3 OTR at traction of orqanosilane-healed films
Samples 50 nm SiOx-coated 12 μm PET films were prepared in roll form at a liquid film coating pilot line for coating of the organosilane layer on the SiOx side and subsequently curing by UV-irradiation prior to rewinding MAPS-1 and MAPS-2 were formulations with Gamma-methacryloxypropyltriethoxysilane diluted in ethanol at 3 weιght-% with the addition of an amount of 2 to 5 volume-% of photo-initiators PI-1 and PI-2 respectively VS-1 and VS-2 were formulations with Vinyltrimethoxysilane diluted in ethanol at 3 weιght-% with the addition of an amount of 2 to 5 weιght-% of photo-initiators PI-1 and PI-2 respectively (see Table 1 2 for PI-1 and PI-2 compounds) The 4 organosilane formulations have been applied at a thickness of about 25 nm prior to the UV-curing irradiation step and coil rewinding Film samples taken from the prepared coils were mounted on the apparatus for measuring OTR of strained samples as described above
Table 3 1 summarizes the OTR data for the respective treatments with MAPS-1 , MAPS-2, VS-1 and VS-2 formulations Figure 3 shows semi-log plots of the OTR data as a function of nominal strain This figure shows also the OTR data taken from strained SiOx/PET samples without the organosilane treatment from Table 2 2 The effect of the UV-cured organosilane is clearly observable by comparing the COS position of the different samples The non-treated SiOx/PET samples have a COS at 2% nominal strain, whilst MAPS-treated and VS-treated SiOx/PET samples show COS at 3%, 4% and beyond 5% depending on the photo-initiator compounds, PI-1 or PI-2, mixed in the solution The photoinitiator no 2, i e the ammo-functional photoinitiator, produced the best improvement of COS, and OTR
Table 3 1 OTR points taken from strained SiOx layers 50 nm thick treated with MAPS-1, MAPS-2, VS-1 and VS-2 healing formulations
Figure imgf000015_0001
Figure 3 shows semi-log plots of OTR data taken during straining of 50 nm thick SiOx barrier coatings deposited on PET 12 mm films by PECVD The graph shows the OTR behaviour for non-treated SiOx/PET samples and SiOx/PET samples treated with the organosilane formulations MAPS-1 , MAPS-2, VS-1 and VS-2
From the above data, it is obvious that the VS-2 healing composition (3% Vinylsilane with photo-initiator PI-2 in ethanol) was the best formulation Therefore, eight consecutive tests with this particular healing composition were carried out to check the repeatability of the results Table 3 2 lists the OTR results of samples under strain and treated with the VS-2 formulation The semi-log plots of Figure 4 depict the behaviour for the eight VS-2 treated SiOx/PET samples For ease of comparison, the OTR data of the non-treated SiOx/PET samples from Table 2 2 are plotted in Figure 4
Table 3 2 OTR points taken from 8 straining tests on SiOx layers 50 nm thick treated with VS-2 organosilane formulation
Figure imgf000016_0001
Figure 4 shows the semi-log plots of the OTR data taken from strained SiOx 50 nm thick barrier coatings deposited on PET 12 mm films by PECVD. The graph shows the OTR behaviour of the eight SiOx/PET samples treated with the VS-2 organosilane formulation It shows also the behaviour of non-treated SiOx/PET samples as a function of nominal strain.
Figure 4 shows the typical behaviour of healed samples where the OTR is constant below the critical strain (COS) and increases dramatically beyond this point. Out of the eight samples, seven have a COS at 5 %, whilst 6% is reached by one sample. For the non-treated 50-nm thick SiOx layers, the behaviour is much different from the organosilane-modified samples: the COS is localized around 2% nominal strain and the OTR1 at 5%, reaches 100-cm3/m2/day/bar.
One other important feature of the polysiloxane formation is the improvement of oxygen barrier of healed SiOx layers. This improvement is clearly shown in Fig. 4, where all treated samples exhibit a much lower OTR compared to 1.6- cm3/m2/day/bar for non treated sample.
Averaging OTR measurements for each data point gives a clear picture of the healing effectiveness of the VS-2 organosilane formulation compared to the non- treated 50-nm SiOx/PET sample data from Table 2.2. This is showed at Figure 5, which presents OTR data in a linear plot.
Figure 5 shows the OTR data taken from strained 50 nm thick SiOx barrier coatings deposited on PET 12-mm films by PECVD. The graph shows the average OTR data from the eight SiOx/PET samples treated with the VS-2 organosilane formulation and the behaviour of the 3 non-treated SiOx/PET samples of Table 2.2
For cost reduction it is interesting to coat polymer films with as thin oxide coating as possible. To this end a similar study was performed on 10-nm SiOx barrier layer deposited on PET 12-μm films by PECVD. After subsequent VS-2 organosilane treatment and UV-curing, film samples have been submitted to the strain OTR test. The data are presented in Table 3.3 and are plotted in Figure 6. In this Figure the OTR measurements of non-treated samples of Table 2.1 are also plotted.
Table 3.3: OTR points taken from 3 straining tests on SiOx layers 10 nm thick treated with VS-2 organosilane formulation
Figure imgf000018_0001
Figure 6 shows OTR data taken from strained 10 nm thick SiOx barrier coatings deposited on PET 12-μm films by PECVD. The graph shows the average OTR from the three SiOx/PET samples treated with the VS-2 organosilane formulation of Table 3.3 and the behaviour of the non-treated SiOx/PET samples of Table 2.1
The oxygen barrier of the treated samples increase with the formation of the polysiloxane hybrid and the corresponding COS is between 5 and 6% nominal strain. The improvement is less drastic than for the thicker SiOx layers. One other feature of SiOx oxide barriers is the COS position dependence on the SiOx thickness. This dependence is clearly seen when looking at the COS positions of non-treated samples of 10 nm and 50 nm thickness, respectively. The COS of the 10 nm thick SiOx layers is positioned at 4%, whilst at 2% only for 50 nm thick SiOx layers (Fig. 3 and 6). This difference might explain why the healing effect of the crosslinked organosilane is less active with the thinner SiOx layer.
The conclusions from the above Examples are, thus, the following.
The 50 nm and 10 nm un-coated not organosilane-healed SiOx/PET samples have COS at 2% and 4%, respectively.
The 3% Vinylsilane-coated 50 nm and 10 nm SiOx/PET samples have COS at 6% and 5.5% respectively.
By coating 3% VS-2, a tremendous improvement of the COS of 50 nm SiOx/PET has been observed while the same silane shows a smaller improvement of the COS of 10 nm SiOx/PET. By coating 3% VS-2, a large decrease of the oxygen transmission OTR is furthermore observed for both 10 nm and 50 nm SiOx/PET samples.
REFERENCES
1. Chwang AB, Rothman MA, Mao SY, et al., Appl. Phys. Lett., 83, 413 (2003).
2. Leterrier Y., Prog. Mater. ScL, 48, 1 (2003). 3. Roberts, A P, Henry, B M, Sutton, et al., J. Membr. ScL1 208, 75 (2002).
4. Rochat, G., Leterrier, Y., Fayet, P. and Manson, J.-A.E., Surf. Coat. Technol., 200/7, 2236 (2005).
5. Rochat, G., Leterrier, Y., Plummer, C. J. G., et al., J. Appl. Phys., 95, 5429-5434 (2004). 6. Rochat G., Delachaux A., Leterrier Y., et al., Surf. Interf. Anal., 35, 948-952 (2003).
7. Rochat G., Leterrier Y., Garamszegi L., et al., Surf. Coat. Technol., 174-175, 1029-1032 (2003).
8. M. Schaepkens, T.W. Kim, A.G. Erlat, M. Yan, K. W. Flanagan, CM. Heller and P.A. McConnelee, UJ. Vac. Sci. Technol. A, 2004. 22: p. 1716.
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Claims

1. Barrier film for encapsulation of oxygen and moisture sensitive devices comprising a base polymer substrate and applied onto the base substrate, a barrier layer comprising an inorganic coating deposited by a vapour deposition method, characterised in that the deposited barrier coating is further coated with a healing layer consisting of a crosslinked organopolysiloxane, which is covalently bound to the inorganic coating.
2. Barrier film according to claim ^ characterised in that that the inorganic coating comprises, at least at the surface, a metal oxide.
3. Barrier film according to claim 1 or 2, characterised in that the inorganic layer comprises, an oxide selected from the group consisting of silicon oxide and aluminium oxide.
4. Barrier film according to claim 3, characterised in that the inorganic layer comprises silicon oxide further containing covalently bound carbon in its formula (SiOxCy), wherein x is from 0,1 to 2,5 and y is from to 0,1 to 2,5.
5. Barrier film according to claim 1, characterised in that that the inorganic coating comprises, a nitride from the group consisting in silicon nitride.
6. Barrier film according to any one of the preceding claims, characterised in that said deposited inorganic coating has a thickness of from 5 to 500 nm, preferably from 5 to 200 nm.
7. Barrier film according to any one of the preceding claims, characterised in that the base film comprises a polymer layer for receiving the vapour deposited layer, which polymer layer is made of a material selected from the group consisting of polyethyleneterephtalate (PET), polyethylenenaphalene (PEN), polyamide (PA) and fluoropolymers.
8. Barrier film according to any one of the preceding claims, c h a r a c t e r i s e d in that the base film comprises a polymer layer for receiving the vapour deposited layer, which polymer layer is made of a material selected from the group consisting of polyimide (Pl), polyethesulfone (PES) and high glass transition temperature aromatic polyesters.
9. Barrier film according to any one of the preceding claims, characterised in that said deposited inorganic layer has been applied by means of plasma enhanced chemical vapour deposition (PECVD).
10. Barrier film according to any one of the preceding claims, characterised in that said coated polysiloxane is a crosslinked reaction product from a composition consisting essentially of unsaturated silanes
11. Barrier film according to any one of the preceding claims, characterised in that said coated polysiloxane is a crosslinked reaction product from a composition consisting essentially of a reactive unsaturated silane selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, butenyltrimethoxysilane, butenyltriethoxysilane, gamma-metacryloxypropyltriethoxysilane gamma- metacryloxypropyltrimethoxysilane, gamma-acryloxypropyltriethoxysilane gamma-acryloxypropyltrimethoxysilane, vinyltriacetoxysilane and mixtures thereof.
12. Barrier film according to any one of the preceding claims, characterised in that said coated polysiloxane is a crosslinked reaction product from a composition consisting essentially of a reactive unsaturated silane selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane and mixtures thereof.
13. Barrier film according to any one of the preceding claims, characterised in that said coated polyorganosiloxane has a thickness of from 1 to 50 nm, preferably from 1-30 nm, more preferably from 10 to 30 nm.
14. Multilayer polymer composite film for encapsulation of oxygen and moisture sensitive devices comprising the barrier film according to any one of claims 1- 13.
15. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices as specified in any one of claims 1-12, comprising the steps of providing a base film of a polymer applying onto the base film, a barrier layer comprising an inorganic coating by means of a vapour deposition method further coating said vapour deposited inorganic coating characterised in that the further coating step comprises the steps of providing a composition consisting essentially of a reactive unsaturated silane compound having three silanol-forming groups dissolved in a solvent - coating the composition onto the inorganic vapour deposited coating subjecting the coated composition to hydrolysis and condensation reaction to provide an ethylenically unsaturated organosiloxane oligomer, which is covalently bound to the inorganic coating curing the coated organosiloxane oligomer to provide the crosslinked polyorganosiloxane layer.
16. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according to claim 15, characterised in that the curing step is carried out by crosslinking with irradiation energy.
17. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according to claim 16, characterised in that a photoinitiator is added to the healing layer coating composition and the curing is carried out by UV irradiation.
18. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according to claim 17, characterised in that a photoinitiator is added at an amount of from 1 to 10, preferably from 2 to 5 weight-%, more preferably from 3-5 weight-%.
19. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according to any one of claims 15-18, characterised in that the reactive unsaturated silane compound is dissolved in ethanol at a concentration of from 1 to 10 weight-%, preferably from 2 to 6 weight-%, more preferably from 3 to 6 weight-%.
20. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according claim 19, characterised in that the reactive unsaturated silane compound is dissolved in ethanol at a concentration of from 3 to 6 weight-% and coated at a thickness of from 10 nm to 30 nm.
21. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according to any one of claims 15-20, characterised in that the reactive unsaturated silane compound is selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, butenyltrimethoxysilane, butenyltriethoxysilane, gamma-metacryloxypropyltriethoxysilane gamma- metacryloxypropyltrimethoxysilane, gamma-acryloxypropyltriethoxysilane gamma-acryloxypropyltrimethoxysilane, vinyltriacetoxysilane and mixtures thereof.
22. Method of manufacturing a barrier film for encapsulation of oxygen and moisture sensitive devices according to any one of claims 15-21 , characterised in that the reactive unsaturated silane compound is selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane and mixtures thereof.
23. Use of a barrier film or multilayer polymer composite film as specified in any one of claims 1-13 for encapsulation of sensitive devices from oxygen and moisture
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