WO2020221415A1

WO2020221415A1 - Improved top emission device with active organic film and method of processing a substrate

Info

Publication number: WO2020221415A1
Application number: PCT/EP2019/060903
Authority: WO
Inventors: Daniel Severin; Andreas KLÖPPEL; Anke Hellmich; Thomas Werner ZILBAUER
Original assignee: Applied Materials, Inc.
Priority date: 2019-04-29
Filing date: 2019-04-29
Publication date: 2020-11-05
Also published as: CN113748530A

Abstract

A method of manufacturing an organic layer stack on a substrate is described. The method includes depositing an organic layer stack of one or more organic layers over the substrate; exposing the substrate have the organic layer stack of one or more organic layers to a material generating a protective component over the organic layer stack; and depositing a transparent conductive electrode over the organic layer stack having the protective component

Description

IMPROVED TOP EMISSION DEVICE WITH ACTIVE ORGANIC FILM AND METHOD OF PROCESSING A SUBSTRATE

BACKGROUND

Field

[0001] Implementations described herein generally relate to processes for the fabrication of an electro-optical device, particularly a top emission device, having an active organic layer stack.

Description of the Related Art

[0002] Coated substrates may be used in several applications and in several technical fields. For instance, coated substrates may be used in the field of organic light emitting diode (OLED) devices. OLEDs can be used in the manufacture of television screens, computer monitors, mobile phones, other hand-held devices, and the like for displaying information. An OLED device, such as an OLED display, may include one or more layers of an organic material situated between two electrodes that are deposited on a substrate. OLED devices can include a stack of several organic materials, which are for example evaporated in a vacuum chamber of a processing apparatus.

[0003] Top emission OLED devices provide some advantages, for example, the opportunity to have larger light emitting areas. Accordingly, the aperture ratio of the display can be increased. This may result in an improved brightness of a display due to the enlarged emitting surface. For top emission OLED devices, a transparent conductive layer is provided on top of the device. For example, a transparent cathode can be provided as a front contact. The transparent cathode may be a common electrode to individual pixels. The transparent, common electrode can bias the active area of a pixel between the transparent conductive electrode and individual pixel electrodes. [0004] Top-emission OLED devices often suffer from OLED damaging when coating the conductive front contact on top of the devices, i.e. over an organic layer or a stack of organic layers. Accordingly, for mass production of top-emission OLED devices, it can be difficult to arrive at damage free OLED devices.

[0005] Thus, there is a need for an improved method of manufacturing OLED devices and for improved OLED devices.

SUMMARY

[0006] In light of the above, a method of processing a substrate and a layer stack for an OLED device are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0007] According to one embodiment, a method of manufacturing an organic layer stack on a substrate is provided. The method includes depositing an organic layer stack of one or more organic layers over the substrate; exposing the substrate have the organic layer stack of one or more organic layers to a material generating a protective component over the organic layer stack; and depositing a transparent conductive electrode over the organic layer stack having the protective component.

[0008] According to one embodiment, a method of manufacturing a top emission OLED device on a large area substrate is provided. The method includes depositing a reflective layer over the large area substrate; depositing an organic layer stack of one or more organic layers over the reflective layer; exposing the substrate have the organic layer stack of one or more organic layers to a material generating a protective component over the organic layer stack; and sputtering a transparent conductive oxide over the organic layer stack having the protective component.

[0009] According to one embodiment, a layer stack for an active organic emission device is provided. The layer stack includes a substrate; an organic layer stack having one or more layers of an organic material; a protective component over the organic layer stack; and a transparent conductive electrode over the protective component. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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 implementations, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary implementations and are therefore not to be considered limiting of scope, and may admit to other equally effective implementations.

[0011] FIG. 1 illustrates a schematic, cross-sectional view of an exemplary OLED device according to embodiments of the present disclosure;

[0012] FIGS. 2A to 2D illustrate a schematic, cross-sectional view of a workpiece processed according to embodiments of the present disclosure;

[0013] FIGS. 3 A to 3D illustrate a schematic, cross-sectional view of a workpiece processed according to embodiments of the present disclosure;

[0014] FIG. 4 illustrates a flow diagram depicting a method of processing a substrate according to embodiments of the present disclosure; and

[0015] FIG. 5 illustrates a flow diagram depicting a method of processing a substrate according to embodiments of the present disclosure.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one implementation may be beneficially incorporated in other implementations without further recitation. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations. Many of the details, dimensions, angles and other features shown in the figures are merely illustrative of particular implementations. Accordingly, other implementations can have other details, components, and features without departing from the spirit or scope of the present disclosure. In addition, further implementations of the disclosure can be practiced without several of the details described below.

[0018] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment can apply to a corresponding part or aspect in another embodiment as well.

[0019] Embodiments of the present disclosure provide a protective component for an organic film stack. The protective component can be deposited over or on, e.g. directly on, an organic layer stack or layer stack with some layers containing organic materials. The protective component can reduce or prevent the one or more organic layers from being damaged during subsequent deposition of a transparent conductive layer, for example, as a front contact of the OLED device. A transparent conductive layer or a conductive layer may have a single layer absorbance of 30% or below, such as 10% or below. For example, a transparent cathode can be provided as a front contact. The conductive layer may be provided by a transparent conductive material, such as a transparent conductive oxide (TCO) or by a thin conductive layer.

[0020] According to an embodiment, a method of processing a substrate is provided. The method includes depositing an organic layer stack of one or more organic layers over the substrate. The substrate having the organic layer stack of the one or more organic layers is exposed to material, generating a protective component over the organic layer stack. A transparent conductive electrode, e.g. a transparent conductive layer or a conductive layer, is deposited over the organic layer stack having the protective component.

[0021] According to embodiments of the present disclosure, which can be combined with the embodiments described herein, the one or more organic layers can be deposited by a vacuum deposition process, such as PVD process, e.g. evaporation, or by other deposition techniques such as printing, for example, ink jet printing.

[0022] FIG. 1 illustrates an exemplary device 100. The device 100 can be an electro-optical device, for example, for emission of light. For example, the device can be a display. The device 100 includes one or more layers of active organic material for photon emission.

[0023] FIG. 1 shows a substrate 102. A reflective layer 104 can be provided over the substrate. The reflective layer reflects light emitted by the OLED material. Accordingly, the emission to the top of the device (corresponding to the top in FIG. 1) can be increased. An assembly for activating a pixel of, for example, a display is schematically shown in FIG. 1. FIG. 1 shows a gate 112 and schematically further components 114 of the transistor, for example, a TFT. An electrode 116 for control of the pixel is provided.

[0024] One or more organic layers 130 form an organic layer stack. A transparent conductive electrode 118 is provided over the organic layer stack. The transparent conductive electrode 118 can be provided for a plurality of pixels, such as for the pixels of the display. As shown in FIG. 1 and as illustrated in further detail with respect to FIGS. 2A to 2D and 3A to 3D, a protective component 120 is provided over the organic layer stack. According to some embodiments, which can be combined with other embodiments described herein, the protective component can be provided below the transparent conductive electrode 118, i.e. between the organic layer stack and the transparent conductive electrode. [0025] According to embodiments of the present disclosure, the protective component can be a protective material, for example, a thin layer that may not fully cover the organic layer stack, or the protective component can be a protective layer fully covering the organic material. The protective material may also referred to as a sacrificial oxidation material or a“sacrificial anode”. In the following, the protective component may also be refer to a protection layer irrespective of whether or not a full coverage of the organic layer stack is provided, i.e. irrespective of whether or not the protection layer or the protection component is thick enough to fully cover the organic layer stack.

[0026] According to some embodiments, which can be combined with other embodiments described herein, the protection layer can be a non-oxygen containing metal layer. The metal layer without oxygen can include a metal or a metal alloy. The oxygen free metal layer or metal alloy layer can be oxidized in subsequent processes.

[0027] For top emission OLED devices, a transparent and conductive layer is deposited over the organic layer stack, i.e. the active OLED material, for example, as a front contact. For mass production of displays, layers are beneficially deposited for a plurality of displays on large area substrates.

[0028] In the present disclosure, a“large area substrate” can have a main surface with an area of 0.15 m² or larger, particularly of 0.3 m² or larger. In some embodiments, a large area substrate can be GEN 4.5, which corresponds to about 0.67 m² of substrate (0.73x0.92m), GEN 5, which corresponds to about 1.4 m² of substrate (1.1 m x 1.3 m), GEN 7.5, which corresponds to about 4.29 m² of substrate (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7 m² of substrate (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m² of substrate (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented. For example, for OLED display manufacturing, half sizes of the above mentioned substrate generations, including GEN 4.5 half-cut, GEN 6, or GEN 6 half-cut, can be coated by evaporation of an apparatus for evaporating material. The half sizes of the substrate generation may result from some processes running on a full substrate size, and subsequent processes running on half of a substrate previously processed.

[0029] Deposition on large area substrates of transparent conductive layers may use a plasma process, which can result in OLED layer damage during coating. The complete OLED device may be damaged due to oxidation and/or energetic input during the layer growth of the transparent conductive electrode. Embodiments of the present disclosure having an additional protection layer, i.e. protective component can reduce or prevent damage of the organic material.

[0030] For example, the transparent conductive electrode can be a transparent conductive oxide. According to some embodiments, which can be combined with other embodiments described herein, the transparent conductive oxide can be selected from the group consisting of: indium tin oxide, IZO (In-Zn-O), ZnO:x (wherein x may be Al, Ga, etc.), SnO:x (wherein x may be Sb, F, etc.). For the manufacturing of OLED devices, particularly indium tin oxide (ITO) may be applicable to provide a transparent conductive electrode, i.e. a transparent anode, for the OLED device.

[0031] According to some embodiments, which can be combined with other embodiments described herein, the transparent conductive electrode can be deposited with a PVD process, such as a sputtering process. For example, a magnetron sputtering process can be provided. The sputtering process can be provided on a large area substrate as described herein.

[0032] As shown in FIG. 2A, a substrate 102 is provided. For instance, the substrate may be made of a material selected from the group consisting of glass (for instance soda-lime glass, borosilicate glass etc.), metal, polymer, ceramic, compound materials, carbon fiber materials or any other material or combination of materials which can be coated by a deposition process.

[0033] The substrate 102 can be processed to have a plurality of elements 204, such as, for example, a reflective layer to improve top emission, a TFT backplane, or other structures and layers for operation of an OLED device. [0034] At operation 402, as shown in FIG. 4, an organic layer stack 130 (see FIG. 2B) is provided over the substrate 102. The organic layer stack can include one or more organic layers. The one or more organic layers include active organic material for light emission. The active organic material emits light due to a voltage provided between the pixel electrode 116 (see FIG. 1) and the transparent conductive electrode 118.

[0035] At operation 404, the substrate having the organic layer stack is exposed to material generating a protective component over the organic layer stack. FIG. 2C shows a protective component or a protection layer as protective material 220 (i.e. a material serving as a“sacrificial anode”). For example, the protective material can be chromium (Cr), chromium alloy, nickel chromium (NiCr) or a nickel chromium alloy. According to yet further embodiments, the sacrificial anode material, i.e. an oxygen catching layer (or“sacrificial Layer”), can include: Zr, Hf, Ti, In, Ag, Al, In, InSn, InZn, Ga, GaZn, Ti, Nb, Mn, alkali metals (Li, Na, K, Cs), alkaline earth metals (Mg, Ca, Sr, Ba), Sc, Y, La, and lanthanides (Ce, Nd, Sm, Eu, Dy) and alloys of the above materials, understoichiometric oxides from the above materials, and understoichiometric fluorides or fluorides.. According to some embodiments, the protective material can be deposited to have a material thickness of 5 nm or below, particularly 2 nm or below.

[0036] At operation 406, a transparent conductive electrode 118 is deposited over the protective component, for example, the protective material 220 shown in FIGS. 2C and 2D. According to some embodiments, which can be combined with other embodiments described herein, the deposition of the transparent conductive electrode is provided without vacuum breakage after the deposition of the protective component. The substrate is maintained in a vacuum atmosphere between the formation of the protective component and the deposition of the transparent conductive electrode.

[0037] The protective material, for example, a nickel chromium alloy is oxidized to some extend (fully or partially) in a subsequent deposition, i.e. as a“sacrificial anode”, that may partially or fully oxidized during deposition of a TCO. The protective material can prevent or reduce organic material of the organic layer stack being oxidized during the subsequent deposition of the transparent conductive electrode, for example, a layer of transparent conductive oxide.

[0038] As shown in, for example, FIG. 2C, the protective material may be provided with the thickness of the protection layer of 2 nm or below, for example about 1 nm. Accordingly, the material may not fully cover the organic layer stack. Organic material may still be exposed. An area of 99% or below, e.g. of 80% or below, of the organic material may be covered. Due to the material selection, oxygen atoms or oxygen-containing molecules existent during deposition of the transparent conductive electrode, for example, a layer of a transparent conductive oxide, interacts with the protective material. Oxidation of organic material can be reduced or prevented.

[0039] According to some embodiments, which can be combined with other embodiments described herein, a further transparent conductive electrode (not shown in FIGS. 2A to 2D) can be deposited over the organic layer stack. For example, the transparent conductive electrode, such as a transparent conductive electrode common to a plurality of pixels, may additionally include a thin metal layer. For example, a metal layer may include silver. According to additional or alternative modifications, the metal layer may have a layer thickness of 20 nm or below, and for example from 10 nm or above such as from 15 nm to 20 nm. According to some embodiments, which can be combined with other embodiments described herein, a metal layer, such as silver layer, e.g. a thin silver layer, can be provided over the organic layer stack, the protective material can be provided over the metal layer, and the transparent conductive oxide can be deposited over the protective material. As described herein, the transparent conductive oxide can be a transparent conductive electrode and the metal layer may serve as a further transparent conductive electrode.

[0040] FIGS. 3 A to 3D illustrate yet further embodiments of the present disclosure. The substrate 102 can be processed to have a plurality of elements 204 and an organic layer stack 130 is provided over the substrate 102 (see, for example, operation 402 in FIG. 4). Operation 404 results in a protective layer 320 as shown in FIG. 3C. According to some embodiments, which can be combined with other embodiments described herein, the protective layer forming the protective component can be a metal alloy. The metal alloy can be oxidized in a subsequent operation or during operation 406 of depositing the transparent conductive electrode 118 (see FIG. 3D).

[0041] According to some embodiments, which can be combined with other embodiments described herein, the protective layer including, for example, a metal alloy, can have thickness of about 10 nm or above, for example, about 10 nm to about 20 nm. The protective layer may fully cover the organic layer stack.

[0042] According to some embodiments, which can be combined with other embodiments described herein, the metal alloy can include indium, indium alloys, InSn alloys, zinc, zinc alloys, ZnAl alloys, InZn, Sn and alloys of InZn and Sn. According to some embodiments, which can be combined with other embodiments described herein, the metal alloy of the protective layer includes at least one element or at least one alloy provided for the transparent conductive electrode.

[0043] For example, if indium tin oxide (ITO) is used as a transparent conductive oxide for the transparent conductive electrode, an InSn alloy can be provided as the protective layer. If ZnO:Al is used as the transparent conductive oxide for the transparent conductive electrode, a ZnAl alloy can be used as the protective layer. Accordingly, the protective layer can include at least one first chemical element and the transparent conductive electrode includes at least the same first chemical element. Particularly, the metal alloy of the protective layer includes the same element(s) as a transparent conductive oxide forming the transparent conductive electrode.

[0044] A metal alloy of a protective layer as described with respect to FIGS. 3 A to 3D may have a potentially lower reactivity as compared to protective material described herein. Accordingly, a protective layer of a metal alloy may have a larger thickness as compared to a protective component including protective material described with respect to FIGS. 2A to 2D. The thicker protection layer may compensate for the lower reactivity. Further, the thicker layer may beneficially protect from energetic input of a subsequent plasma process depositing the transparent conductive electrode, such as a sputtering process.

[0045] According to some embodiments, which can be combined with other embodiments described herein, the metal alloy protective layer can be oxidized after deposition of the protective component and before depositing the transparent conductive electrode. Additionally or alternatively, the metal alloy can be oxidized or further oxidized during the coating of the transparent conductive electrode, for example, a transparent conductive oxide.

[0046] FIG. 5 illustrates a flow diagram of an exemplary method for processing a substrate, particularly for manufacturing an OLED device. At operation 502, the reflective layer is deposited over the substrate. For example, the reflective layer according to embodiments of the present disclosure can be a metal layer or a TCO / Metal/ TCO stack. For example, the reflective layer may be a reflective electrode. For example, a pixel electrode may serve as a reflective layer with a high reflectivity to reflect photos generated by an active organic material to participate at top emission of the OFED device.

[0047] One or more organic layers are deposited over the substrate to form an organic layer stack. This is indicated by operation 402. The reflective layer is provided between the substrate and the organic layer stack. Similar to operation 404 described with respect to FIG. 4, the protective component is formed. The protection component can be protective material or a protective layer. At operation 504, the protective component can be oxidized in an optional operation, particularly partially oxidized or pre-oxidized. According to some embodiments, the protective component, i.e. the protective material or the protective layer can be partially oxidized or pre-oxidized during generation of the protective component or after generation, i.e. deposition, of the protective component over the organic layer stack. At operation 506, a transparent conductive oxide is sputtered over the organic layer stack having the protective component. [0048] According to some embodiments, which can be combined with other embodiments described herein, a further transparent conductive electrode (not shown in FIGS. 3 A to 3D) can be deposited over the organic layer stack. For example, the transparent conductive electrode, such as a transparent conductive electrode common to a plurality of pixels, may additionally include a thin metal layer. For example, a metal layer may include silver. According to additional or alternative modifications, the metal layer may have a layer thickness of 20 nm or below. According to some embodiments, which can be combined with other embodiments described herein, a metal layer, such as silver layer, e.g. a thin silver layer, can be provided over the organic layer stack, the protective material can be provided over the metal layer, and the transparent conductive oxide can be deposited over the protective material. As described herein, the transparent conductive oxide can be a transparent conductive electrode and the metal layer may serve as a further transparent conductive electrode.

[0049] Embodiments of the present disclosure also refer to a layer stack for an OLED device, such as an active organic emission device manufactured according to any of the embodiments described herein. For example, exemplary layer stacks are shown in FIG. 1, FIG. 2D and FIG. 3D. A layer stack includes a substrate, an organic layer stack having one or more layers of organic material, a protective component over the organic layer stack, and a transparent conductive electrode over the protective component. Optionally a further conductive electrode may be provided between the organic layer stack and the transparent conductive electrode.

[0050] The present disclosure relates to the term“over” with respect to a second layer, or the like being provided over a first layer or the like, in the event optionally a further layer or the like may be provided between the first layer and the second layer. A direct contact of a first layer and a second layer is described as the second layer being directly on the first layer.

[0051] Embodiments of the present disclosure protect an OFED stack and enable top emission OFED device production using large area PVD equipment, such as for example deposition systems utilizing sputtering on large area substrates. [0052] While the foregoing is directed to implementations of the present disclosure, other and further implementations 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. A method of manufacturing an organic layer stack on a substrate, comprising: depositing an organic layer stack of one or more organic layers over the substrate; exposing the substrate have the organic layer stack of one or more organic layers to a material generating a protective component over the organic layer stack; and depositing a transparent conductive electrode over the organic layer stack having the protective component.

2. The method of claim 1, wherein the transparent conductive electrode includes a transparent conductive oxide.

3. The method of claim 2, wherein the transparent conductive oxide is selected from the group consisting of: indium tin oxide, IZO (In-Zn-O), ZnO:x, and SnO:x.

4. The method of claim 3, wherein the transparent conductive oxide is indium tin oxide.

5. The method of any of claims 1 to 4, wherein the transparent conductive electrode is deposited with a PVD process, particularly sputtered over the organic layer stack.

6. The method of any of claims 1 to 5, wherein the protective component is a protective material deposited over the organic layer stack.

7. The method of claim 6, wherein the protective material has a material thickness of 10 nm or below, particularly 5 nm or below, more particularly 2 nm or below.

8. The method of any of claims 6 to 7, wherein the protective material does not fully cover an area of the organic layer stack.

9. The method of any of claims 6 to 8, wherein the protective material is selected from the group consisting of: Cr, a Cr alloy, NiCr, Zr, Hf, Ti, In, Ag, , Al, In, InSn, InZn, Ga, GaZn, Ti, Nb, Mn, alkali metals (Li, Na, K, Cs), alkaline earth metals (Mg, Ca, Sr, Ba), Sc, Y, La, and lanthanides (Ce, Nd, Sm, Eu, Dy) and alloys of the above materials, understoichiometric oxides from the above materials, and understoichiometric fluorides or fluorides.

10. The method of claim 9, wherein the protective material is NiCr.

11. The method of any of claims 1 to 5, wherein the protective component is a protective layer of a metal alloy.

12. The method of claim 11, wherein the protective layer is oxidized after deposition of the protective layer.

13. The method of any of claims 11 to 12, wherein the protective layer has a layer thickness of 5 nm or more.

14. The method of any of claims 11 to 13, wherein the protective layer includes at least one first chemical element and wherein the transparent conductive electrode includes at least the first chemical element, particularly wherein the metal alloy of the protective layer includes the same element as a transparent conductive oxide forming the transparent conductive electrode.

15. The method of any of claims 1 to 14, further comprising: depositing a reflective layer between the substrate and the organic layer stack.

16. The method of any of claims 1 to 15, further comprising: depositing a further conductive electrode between the organic layer stack and the transparent conductive electrode.

17. A method of manufacturing a top emission OLED device on a large area substrate, comprising: depositing a reflective layer over the large area substrate; depositing an organic layer stack of one or more organic layers over the reflective layer; exposing the substrate have the organic layer stack of one or more organic layers to a material generating a protective component over the organic layer stack; and sputtering a transparent conductive oxide over the organic layer stack having the protective component.

18. A layer stack for an active organic emission device; comprising: a substrate; an organic layer stack having one or more layers of an organic material; a protective component over the organic layer stack; and a transparent conductive electrode over the protective component.

19. The layer stack of claim 18, further comprising: a further conductive electrode between the organic layer stack and the transparent conductive electrode.