JP2011083990A - Gas barrier layer structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas barrier layer structure best suited as a barrier layer for electronic device by reducing an amount of water vapor transmission as compared with that of a conventional technique. <P>SOLUTION: A gas barrier layer structure 6 demonstrating gas barrier properties in an electronic device structure is composed of a layer 61 of a passive metal and a layer 62 of an oxide of passive metal laminated in sequence, wherein the passive metal is selected from Al, Cr, Ti, Ni, Fe, Zr and Ta or an alloy of two or more of them. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas barrier layer structure that exhibits gas barrier performance particularly against water vapor in electronic devices such as organic electroluminescence (hereinafter referred to as “organic EL”) elements, solar cells, and thin film lithium batteries.

  This type of electronic device includes those that are easily deteriorated by gas such as water vapor and oxygen in the atmosphere, and in order to increase durability, it is necessary to provide the electronic device with a structure that specifically blocks water vapor. It has been known for some time.

  Here, in Patent Document 1, in an organic EL element, a polymer compound film is provided so as to cover the surface of the organic EL element and the surrounding substrate, and then the polymer compound film, its edge and its surroundings are covered. It is disclosed that an inorganic barrier film made of an alumina layer or the like is provided so as to cover the substrate surface.

  Patent Document 2 discloses an organic polymer or organometallic complex that functions as a diffusion barrier against oxygen and water vapor after a pixel array of an organic light emitting device (LED) is capped with a stable metal layer such as indium (In). It is disclosed to provide either buffer layer.

  However, when the barrier layer is formed from a single oxide or nitride layer or resin as in the above conventional example, the water vapor permeation amount is still large, and the water vapor barrier property is sufficient to reliably prevent deterioration of the device. It turned out that was not obtained.

JP 2007-134099 A JP-A-9-185994

  In view of the above points, it is an object of the present invention to provide a gas barrier layer structure that can reduce the amount of water vapor permeation particularly as compared with that of the prior art and is optimal as a barrier layer for electronic devices. .

  In order to solve the above-described problems, the present invention provides a gas barrier layer structure that exhibits gas barrier performance in an electronic device structure, and includes a passivation metal layer and an oxide layer of the passivation metal in order. It is characterized by being laminated.

  According to the present invention, by laminating the passivated metal oxide layer on the passivated metal layer, the thickness is about the same as the total thickness of the passivated metal layer and the oxide layer. It was confirmed that the amount of water vapor permeation can be reduced to about 1/5 as compared with the barrier layer of the above-described conventional example composed of a single layer of oxide or nitride. This is considered that when this oxide layer was laminated on the passivating metal layer, the oxide layer existing in the vicinity of the interface between the two was modified to exert a strong water vapor barrier property. .

  In addition, the electronic device in this invention means electronic components with specific functions, such as an organic EL element, a solar cell, and a thin film lithium battery, and is not limited to the thing of the said illustration. Further, when the passivating metal is Al, the thickness of the Al layer needs to be thin, for example, about 5 nm, compared with the oxide layer of the passivating metal. Here, in order to reduce the amount of water vapor permeated, the thickness of the Al layer may be increased. However, as the thickness of the Al layer increases, the insulating property decreases. For this reason, it may become unsuitable depending on a use. Further, it is necessary to adjust the thickness of the Al layer even when optical transparency is required in the electronic device to which the present invention is applied.

  In the present invention, the passivating metal may be selected from Al, Cr, Ti, Ni, Fe, Zr and Ta, or an alloy of two or more of these.

  In the present invention, the passivating metal layer and the passivating metal oxide layer are preferably formed successively by a sputtering method. According to this, a passivation layer and an oxide film layer made of a dense film can be continuously formed in a vacuum only by introducing an oxygen reactive gas during sputtering, which improves production costs and productivity. This is advantageous.

The figure explaining the structure of the organic EL element to which the gas barrier layer structure of this invention is applied. The figure which shows the measurement result of the water vapor transmission rate by the gas barrier layer structure of this invention. The graph which shows a sheet resistance value when the film thickness of a passivation layer is changed in the gas barrier layer structure of the present invention. The figure explaining the structure of the thin film lithium ion battery which can apply the gas barrier layer structure of this invention.

  Embodiments of the present invention will be described below with reference to the drawings, taking as an example the case where the gas barrier layer structure of the present invention is applied to an organic EL element.

  Referring to FIG. 1, D1 is an organic EL element. The organic EL element D1 includes a first display electrode 2 constituting an anode, one or more organic functional layers 3 composed of an organic compound, and a cathode constituting a cathode on the surface of a substrate 1 such as an inorganic substance such as glass. 2 display electrodes 4 are sequentially stacked, and the organic functional layer 3 is sandwiched between an anode and a cathode.

The first display electrode 2 is made of, for example, an ITO film, is formed by a known method such as an EB vapor deposition method or a sputtering method, and is patterned into a predetermined shape by a photolithography process. The organic functional layer 3 has a known structure, for example, by a vapor deposition method, a hole injection layer made of copper phthalocyanine, a hole transport layer made of TPD (triphenylamine derivative), and Alq3 (aluminum chelate complex). And a light emitting layer made of Li and an electron injection layer made of Li ₂ O are sequentially stacked. The second display electrode 4 is made of, for example, an Al film, is formed by a known method such as EB vapor deposition or sputtering, and is patterned into a predetermined shape by a photolithography process.

  Further, on the surface of the substrate 1 including the organic EL element D1 and the periphery thereof, a polymer compound film 5 and a barrier film 6 covering the polymer compound film 5, an edge thereof, and the substrate 1 surface in the periphery thereof are sequentially laminated. Has been. The barrier film 6 exhibits gas barrier performance against gases such as water vapor and oxygen. As for the polymer compound film 5, since a patent application has been filed by the present applicant and a film described in Japanese Patent Application Laid-Open No. 2007-134099 can be used, for example, detailed description is omitted here.

The barrier film 6 is composed of a gas barrier layer structure in which an Al layer 61 as a passivating metal layer and an Al oxide (Al ₂ O ₃ ) layer 62 are sequentially stacked. The Al layer 61 and the Al ₂ O ₃ layer 62 are continuously formed in a vacuum using the same sputtering apparatus. That is, the film is formed using a known sputtering apparatus (not shown) equipped with a target made of Al (99.99%).

That is, at the beginning of forming the gas barrier layer structure by sputtering, only the sputtering gas such as Ar is introduced into the vacuum chamber of the sputtering apparatus, and predetermined power is supplied to the target to form the Al layer 61 made of Al. Next, when the Al layer 61 reaches a predetermined thickness from the sputtering rate calculated from the input power to the target, the chamber pressure, and the like, a reactive gas composed of oxygen is introduced into the vacuum chamber and Al _{2 is formed} by reactive sputtering. The O ₃ layer 62 is formed with a predetermined thickness. In this case, the thickness of the Al layer 61 is preferably 5 nm or less. When the thickness of the Al layer 61 exceeds 5 nm, there arises a problem that the insulating property is lowered.

Next, in order to evaluate the gas barrier performance of the gas barrier layer structure 6 of the present embodiment, the following experiment was performed. A PET film having a thickness of 50 μm was used as the substrate. Then, an Al film having a film thickness of 3 nm is formed on the surface of the film by a known sputtering apparatus equipped with an Al (99.99%) target, and then reactive gas consisting of oxygen is introduced to perform reactive sputtering. An Al ₂ O ₃ layer having a thickness of 50 nm was formed (invention product).

As a comparative experiment, the same film surface as described above, the same sputtering apparatus, and an Al ₂ O ₃ layer with a thickness of 50 nm formed by reactive sputtering (Comparative product 1) and the same film as above An Al ₂ O ₃ layer having a thickness of 50 nm was formed by reactive sputtering on the surface using reactive sputtering, and then the introduction of oxygen was stopped to form an Al film with a thickness of 3 nm. (Comparative product 2) was produced.

FIG. 2 shows the measurement results of the water vapor permeation amount of the inventive product and the comparative product 1 and the comparative product 2. The amount of water vapor permeation was measured by the pressure increase method (Vacuum Volume 35, No. 3, page 317 (1992)). According to this, the water vapor permeation amount of the inventive product is 5.0 × 10 ⁻² g / cm ² / day, which is 1/5 times that of the comparative product 1 that has been widely used conventionally. You can see that In addition, from the comparison product 2 with the product according to the invention and the comparison product 2 in which the stacking order of the Al layer and the Al ₂ O ₃ layer is different (device structure such as a substrate or an organic El element), an Al layer, It was confirmed that sufficient gas barrier properties would not be exhibited unless the laminate was formed in the stacking order of Al ₂ O ₃ layers.

Next, in order to evaluate the insulation of the gas barrier layer structure 6 of the present embodiment, the following experiment was performed. A PET film having a thickness of 50 μm was used as the substrate. Then, an Al film having a predetermined thickness is formed on the surface of the film with a known sputtering apparatus equipped with a target made of Al (99.99%), and subsequently, reactive gas composed of oxygen is introduced for reactive sputtering. An Al ₂ O ₃ layer having a thickness of 50 nm was formed. FIG. 3 is a graph when the sheet resistance value (Ω / □) is measured by changing the thickness of the Al film. The sheet resistance value was measured by a four-terminal four-probe method. According to this, it was confirmed that when the thickness of the Al layer exceeds 5 nm, the sheet resistance value rapidly decreases. Thereby, when using the gas barrier layer structure 6 of this embodiment for a specific device structure, it turns out that it is necessary to consider the film thickness of an Al layer.

As described above, according to the above embodiment, the Al ₂ O ₃ layer 62 that is the passivated metal oxide layer is laminated on the Al layer 61 that is the passivated metal, and these Al films 61 and the Al ₂ O ₃ layer 62 are continuously formed by the same sputtering apparatus to form a dense film, so that the total film of the passivation metal layer and the oxide layer is formed. Compared with the conventional example having the same thickness, the water vapor transmission amount can be greatly reduced.

  In the above embodiment, the gas barrier layer structure 6 is applied to an organic EL element as an example, but the present invention is not limited to this. For example, as shown in FIG. 4, in a thin film lithium ion battery D2 in which a positive electrode current collecting layer, a crystallized positive electrode, a solid electrolyte layer, a negative electrode current collecting layer, and a Li negative electrode are sequentially formed on a substrate. The gas barrier layer structure 60 of the present invention can be applied as a sealing film.

  In the above-described embodiment, the case where Al is used as the passivating metal has been described as an example. However, the present invention is not limited to this and is selected from Cr, Ti, Ni, Fe, Zr, and Ta. Even if it is a thing or these 2 or more types of alloys, there can exist the said effect. In this case, the film thicknesses of the passivating metals Cr, Ti, Ni, Fe, Zr and Ta are appropriately set according to the device to be used, as described above.

D1 ... organic EL element, D2 ... thin-film lithium ion battery, 6,60 ... gas barrier layer structure, 61 ... Al layer (passivation layer of metal), 62 ... _Al 2 _{O 3} layer (oxide of passive metal layer)

Claims (3)

A gas barrier layer structure that exhibits gas barrier performance in an electronic device structure,
A gas barrier layer structure comprising a passivating metal layer and an oxide layer of the passivating metal sequentially laminated.   2. The gas barrier according to claim 1, wherein the passivating metal is selected from Al, Cr, Ti, Ni, Fe, Zr and Ta, or an alloy of two or more thereof. Layer structure.   The gas barrier layer structure according to claim 1 or 2, wherein the passivating metal layer and the passivating metal oxide layer are continuously formed by a sputtering method. .

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