JP7109492B2 - Method for manufacturing organic EL device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organic EL device (eg, an organic EL display device and an organic EL lighting device) and a manufacturing method thereof.

Organic EL (Electro Luminescence) display devices have begun to be put to practical use. One of the features of the organic EL display device is that a flexible display device can be obtained. An organic EL display device has at least one organic EL element (Organic Light Emitting Diode: OLED) for each pixel and at least one TFT (Thin Film Transistor) for controlling current supplied to each OLED. Hereinafter, the organic EL display device will be called an OLED display device. An OLED display device having a switching element such as a TFT for each OLED is called an active matrix type OLED display device. A substrate on which TFTs and OLEDs are formed is called an element substrate.

OLEDs (particularly organic light-emitting layers and cathode electrode materials) are susceptible to deterioration due to the influence of moisture, and display unevenness is likely to occur. A thin film encapsulation (TFE) technique has been developed as a technique for protecting an OLED from moisture and providing an encapsulation structure that does not impair flexibility. Thin-film encapsulation technology aims to obtain sufficient water vapor barrier properties with a thin film by alternately laminating inorganic barrier layers and organic barrier layers. From the viewpoint of moisture resistance reliability of an OLED display device, a WVTR (Water Vapor Transmission Rate) of 1×10 ⁻⁴ g/m ² /day or less is typically required for a thin-film sealing structure.

Thin-film encapsulation structures currently used in commercially available OLED displays have an organic barrier layer (polymeric barrier layer) with a thickness of about 5 μm to about 20 μm. Such a relatively thick organic barrier layer also serves to planarize the surface of the element substrate. However, thicker organic barrier layers have the disadvantage of limiting the flexibility of the OLED display.

Moreover, there is also a problem that mass productivity is low. The relatively thick organic barrier layer described above is formed using a printing technique such as an inkjet method or a microjet method. On the other hand, the inorganic barrier layer is formed in a vacuum (for example, 1 Pa or less) atmosphere using a thin film deposition technique. The formation of the organic barrier layer using printing technology is carried out in the air or nitrogen atmosphere, and the formation of the inorganic barrier layer is carried out in a vacuum. Mass production is low due to loading and unloading.

Therefore, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100002, a film forming apparatus has been developed that can continuously manufacture an inorganic barrier layer and an organic barrier layer.

Further, in Patent Document 2, when a first inorganic material layer, a first resin material, and a second inorganic material layer are formed in this order from the element substrate side, the first resin material is A thin-film encapsulation structure is disclosed that is unevenly distributed around a convex portion of an inorganic material layer (the first inorganic material layer covering the convex portion). According to Patent Document 2, by unevenly distributing the first resin material around a convex portion that may not be sufficiently covered with the first inorganic material layer, the intrusion of moisture and oxygen from that portion is suppressed. Further, since the first resin material functions as a base layer for the second inorganic material layer, the second inorganic material layer is properly formed, and the side surface of the first inorganic material layer is formed to have a desired film thickness. It becomes possible to coat properly with The first resin material is formed as follows. A mist-like organic material vaporized by heating is supplied onto an element substrate maintained at room temperature or lower, and the organic material condenses on the substrate to form droplets. The droplets of the organic material move on the substrate due to capillary action or surface tension, and are unevenly distributed at the boundaries between the side surfaces of the projections of the first inorganic material layer and the substrate surface. After that, the first resin material is formed at the boundary by curing the organic material. Patent Document 3 also discloses an OLED display device having a similar thin-film sealing structure. Further, Patent Document 4 discloses a film forming apparatus used for manufacturing an OLED display device.

JP 2013-186971 A WO2014/196137 JP 2016-39120 A JP 2013-64187 A

It is believed that the thin film encapsulation structures described in US Pat. Moreover, since the inorganic barrier layer and the organic barrier layer can be continuously formed, productivity is also improved.

However, according to the studies of the present inventors, when the organic barrier layer is formed by the method described in Patent Documents 2 and 3, there is a problem that sufficient humidity resistance reliability cannot be obtained.

When the organic barrier layer is formed using a printing method such as an inkjet method, the organic barrier layer is formed only in the active region (also referred to as "element formation region" or "display region") on the element substrate, It can be made so that it is not formed in regions other than the active region. Therefore, in the periphery (outside) of the active region, there is a region where the first inorganic material layer and the second inorganic material layer are in direct contact, and the organic barrier layer is formed between the first inorganic material layer and the second inorganic material layer. completely surrounded by and isolated from the surroundings.

On the other hand, in the method for forming an organic barrier layer described in Patent Documents 2 and 3, a resin (organic material) is supplied to the entire surface of the element substrate, and the surface tension of the liquid resin is utilized to reduce the surface tension of the element substrate. The resin is unevenly distributed on the boundary between the side surface of the projection and the substrate surface. Therefore, a region outside the active region (sometimes referred to as a "peripheral region"), that is, a terminal region where a plurality of terminals are arranged and a lead wiring region where a lead wiring extending from the active region to the terminal region is formed. An organic barrier layer may form. Specifically, for example, the resin is unevenly distributed at the boundary between the side surface of the lead wiring and the terminal and the surface of the substrate. Then, the end of the portion of the organic barrier layer formed along the lead-out wiring is not surrounded by the first inorganic barrier layer and the second inorganic barrier layer, and is exposed to the atmosphere (surrounding atmosphere).

Since the organic barrier layer has a lower water vapor barrier property than the inorganic barrier layer, the organic barrier layer formed along the lead wiring serves as a path for introducing water vapor in the atmosphere into the active region.

Here, the problem of the thin film encapsulation structure suitably used for flexible organic EL display devices has been described, but the thin film encapsulation structure is not limited to organic EL display devices, and other organic EL devices such as organic EL lighting devices. Also used for

In addition, a lower electrode and an organic layer (also referred to as an organic EL layer, including at least an organic light-emitting layer) of an OLED are required to have high flatness. Poor flatness, for example, reduces the luminous efficiency of the OLED. For example, if the flatness of the lower electrode and the organic layer of the OLED is low, there is a problem that even if a microresonator structure is adopted, its effect cannot be sufficiently exhibited.

The present invention was made to solve at least one of the above problems, and an embodiment of the present invention provides a thin film having a relatively thin organic barrier layer with improved mass productivity and moisture resistance reliability. An object of the present invention is to provide an organic EL device having a sealing structure and a manufacturing method thereof. Another embodiment of the present invention aims to provide an organic EL device capable of improving luminous efficiency and a method of manufacturing the same.

An organic EL device according to an embodiment of the present invention comprises a substrate, a plurality of TFTs formed on the substrate, a plurality of gate bus lines and a plurality of source buses each connected to one of the plurality of TFTs. a driver circuit layer having lines, a plurality of terminals, and a plurality of lead wirings connecting the plurality of terminals to either the plurality of gate bus lines or the plurality of source bus lines; and on the driver circuit layer. an organic EL element layer formed on the interlayer insulating layer and having a plurality of organic EL elements each connected to one of the plurality of TFTs; and the organic EL element layer a thin film encapsulation structure formed so as to cover the interlayer insulating layer, the interlayer insulating layer having a contact hole, and a contact portion connecting the drive circuit layer and the organic EL element layer in the contact hole. is formed, the surface of the interlayer insulating layer and the surface of the contact portion are flush with each other, and the arithmetic mean roughness Ra is 50 nm or less.

In one embodiment, each has a plurality of pixels including one of the plurality of organic EL elements, and the contact section is formed inside each of the plurality of pixels.

In one embodiment, each of the plurality of organic EL elements has a lower electrode, an organic layer, and an upper electrode facing the lower electrode via the organic layer, and the contact section is different from the lower electrode. made of material.

In one embodiment, the interlayer insulating layer includes a first inorganic protective layer formed on the drive circuit layer and exposing at least the plurality of terminals, and an organic planarizing layer formed on the first inorganic protective layer. and the surface arithmetic mean roughness Ra of the organic planarizing layer is 50 nm or less.

In one embodiment, the interlayer insulating layer includes a first inorganic protective layer formed on the drive circuit layer and exposing at least the plurality of terminals, and an organic planarizing layer formed on the first inorganic protective layer. and a second inorganic protective layer formed on the organic planarizing layer, and the surface arithmetic mean roughness Ra of the second inorganic protective layer is 50 nm or less.

In one embodiment, the thin film encapsulation structure has a first inorganic barrier layer, an organic barrier layer in contact with the top surface of the first inorganic barrier layer, and a second inorganic barrier layer in contact with the top surface of the organic barrier layer. and the organic barrier layer is formed in a region surrounded by an inorganic barrier layer junction where the first inorganic barrier layer and the second inorganic barrier layer are in direct contact, When viewed from the line direction, the organic planarization layer is formed in the region in which the first inorganic protective layer is formed, and the plurality of organic EL devices are formed in the region in which the organic planarization layer is formed. an element is arranged, the outer edge of the thin film encapsulation structure intersects with the plurality of lead wires, and is between the outer edge of the organic planarization layer and the outer edge of the first inorganic protective layer; A section of the first inorganic barrier layer parallel to the line width direction of the plurality of lead wires in a portion where the first inorganic protective layer and the first inorganic barrier layer are in direct contact on the plurality of lead wires. The taper angle of the sides in the shape of is less than 90°.

In one embodiment, the taper angle of the side surface of the first inorganic barrier layer is less than 70°.

In one embodiment, the organic planarization layer is formed from polyimide.

A method for manufacturing an organic EL device according to an embodiment of the present invention is a method for manufacturing the organic EL device according to any one of the above, comprising a step A of forming the drive circuit layer on the substrate; A step B of forming an interlayer insulating film having a contact hole on the drive circuit layer, a step C of forming a conductive contact film covering the interlayer insulating film, a surface of the contact film and the interlayer insulating film. and a step D of obtaining the interlayer insulating layer and the contact portion by subjecting the surface of the substrate to chemical mechanical polishing.

In one embodiment, the step C includes a step of forming a titanium film by a sputtering method and a step of forming a copper film on the titanium film by a plating method.

In one embodiment, the step B includes forming a first inorganic protective film on the drive circuit layer, and forming an organic planarizing film on the first inorganic protective film, and After D, a step E of heating the interlayer insulating layer to a temperature of 100° C. or higher, and after the step E, a step F of forming an organic layer included in the organic EL element on the interlayer insulating layer. contain.

In one embodiment, step D includes the step of subjecting the surface of the organic planarization film to chemical mechanical polishing.

In one embodiment, the step B includes forming a first inorganic protective film on the drive circuit layer, forming an organic planarizing film on the first inorganic protective film, and forming the organic planarizing film on the first inorganic protective film. forming a second inorganic protective film thereon; and collectively forming a contact hole penetrating through the first inorganic protective film, the organic planarizing film and the second inorganic protective film, Step D includes the step of subjecting the surface of the second inorganic protective film to chemical mechanical polishing.

According to one embodiment of the present invention, an organic EL display device having a thin-film encapsulation structure with a relatively thin organic barrier layer and a method of manufacturing the same are provided with improved mass productivity and moisture resistance reliability. According to another embodiment of the present invention, an organic EL device capable of improving luminous efficiency and a manufacturing method thereof are provided.

(a) is a schematic partial cross-sectional view of an active region of an OLED display 100 according to an embodiment of the present invention, and (b) is a partial cross-sectional view of a TFE structure 10 formed on an OLED 3. FIG. 1 is a schematic plan view of an OLED display device 100A according to an embodiment of the invention; FIG. (a) and (b) are schematic cross-sectional views of the OLED display device 100A, (a) is a cross-sectional view along line 3A-3A' in FIG. 3B-3B' is a cross-sectional view along line 3B-3B', and (c) is a cross-sectional view showing the taper angle θ of the side surface of each layer. FIG. (a) to (d) are schematic cross-sectional views of the OLED display device 100A, (a) is a cross-sectional view along line 4A-4A' in FIG. 2, and (b) is a cross-sectional view in FIG. 4B-4B' is a cross-sectional view along the line, (c) is a cross-sectional view along the 4C-4C' line in FIG. 2, and (d) is a cross-sectional view along the 4D-4D' line in FIG. It is a sectional view. (a) and (b) are schematic cross-sectional views corresponding to FIG. 4(b) in OLED display devices 100B1 and 100B2 of comparative examples. FIG. 10 is a schematic plan view of an OLED display device 100C of a comparative example; (a) and (b) are schematic cross-sectional views of an OLED display device 100C, (a) is a cross-sectional view along line 7A-7A' in FIG. 7B-7B' is a cross-sectional view along line 7B-7B'; (a) to (c) are schematic cross-sectional views of an OLED display device 100C, (a) is a cross-sectional view along line 8A-8A' in FIG. FIG. 7 is a cross-sectional view taken along line 8B-8B', and (c) is a cross-sectional view taken along line 8C-8C' in FIG. 6; 4A and 4B are schematic cross-sectional views each showing an example of a TFT that the OLED display device according to the embodiment can have; FIG. (a) to (c) are schematic cross-sectional views of other OLED display devices according to embodiments, corresponding to FIGS. 4(b) to (d), respectively. (a) and (b) are schematic cross-sectional views of still another OLED display device 100D according to the embodiment. (a) to (c) are schematic cross-sectional views for explaining the manufacturing method of the OLED display device 100D. (a) and (b) are schematic cross-sectional views of still another OLED display device 100E according to the embodiment. (a) to (c) are schematic cross-sectional views for explaining the manufacturing method of the OLED display device 100E. (a) and (b) are diagrams schematically showing the configuration of the film forming apparatus 200, and (a) shows the structure of the film forming apparatus 200 in the step of condensing the photocurable resin on the first inorganic barrier layer. 4B shows the state of the film forming apparatus 200 in the step of curing the photocurable resin.

Hereinafter, an OLED display device and a method for manufacturing the same according to embodiments of the present invention will be described with reference to the drawings. Although an OLED display device having a flexible substrate is exemplified below, the embodiments of the present invention are not limited to organic EL display devices, and may be other organic EL devices such as organic EL lighting devices. It is not limited to the embodiment to do.

First, the basic configuration of an OLED display device 100 according to an embodiment of the present invention will be described with reference to FIGS. 1(a) and 1(b). FIG. 1(a) is a schematic partial cross-sectional view of an active region of an OLED display 100 according to an embodiment of the present invention, and FIG. 1(b) is a partial cross-sectional view of a TFE structure 10 formed on an OLED 3. is.

The OLED display device 100 has a plurality of pixels, each pixel having at least one organic EL element (OLED). Here, for simplicity, the structure corresponding to one OLED will be described.

As shown in FIG. 1A, an OLED display device 100 includes a flexible substrate (hereinafter sometimes simply referred to as "substrate") 1 and a circuit ("drive circuit") including TFTs formed on the substrate 1. 2, an inorganic protective layer (first inorganic protective layer) 2Pa formed on the circuit 2, and an organic planarizing layer 2Pb formed on the inorganic protective layer 2Pa. , an OLED 3 formed on the organic planarization layer 2Pb, and a TFE structure 10 formed on the OLED 3. FIG. Hereinafter, the substrate 1, the circuit 2 formed on the substrate 1, the inorganic protective layer 2Pa, the organic planarizing layer 2Pb and the OLED 3 are sometimes referred to as an element substrate 20. FIG. In other words, the substrate 1 and the components arranged closer to the substrate 1 than the TFE structure 10 on the substrate 1 are collectively referred to as the device substrate.

OLED 3 is, for example, a top emission type. The top of the OLED 3 is, for example, an upper electrode or a cap layer (refractive index adjusting layer). A layer in which a plurality of OLEDs 3 are arranged is sometimes called an OLED layer 3 . An optional polarizer 4 is placed over the TFE structure 10 . Note that the circuit 2 and the OLED layer 3 may share some components. Further, for example, a layer having a touch panel function may be arranged between the TFE structure 10 and the polarizing plate 4 . That is, the OLED display device 100 can be modified into an on-cell display device with a touch panel.

The substrate 1 is, for example, a polyimide film with a thickness of 15 μm. The thickness of the circuit 2 including TFTs is, for example, 4 μm. The inorganic protective layer 2Pa is, for example, a SiN _x layer (500 nm)/SiO ₂ layer (100 nm) (upper layer/lower layer). In addition, the inorganic protective layer 2Pa may also have a three-layer structure of, for example, SiO ₂ layer/SiN _x layer/SiO ₂ layer, and the thickness of each layer is, for example, 200 nm/300 nm/100 nm. Also, the inorganic protective layer 2Pa may be a single layer of SiN _x layer (200 nm). The organic planarization layer 2Pb is, for example, an acrylic resin layer, an epoxy resin layer, or a polyimide layer with a thickness of 4 μm. The organic planarizing layer 2Pb may be formed using a photosensitive resin, or may be formed using a non-photosensitive resin. The thickness of the OLED 3 is, for example, 1 μm. The thickness of the TFE structure 10 is, for example, 2.5 μm or less.

FIG. 1(b) is a partial cross-sectional view of the TFE structure 10 formed on the OLED 3. FIG. A first inorganic barrier layer (eg, SiN _x layer) 12 is formed directly above the OLED 3, and an organic barrier layer (eg, an acrylic resin layer) 14 is formed on the first inorganic barrier layer 12. The organic barrier layer A second inorganic barrier layer (eg, SiN _x layer) 16 is formed over 14 .

For example, the first inorganic barrier layer 12 is, for example, a _SiNx layer with a thickness of 1.5 μm, the second inorganic barrier layer 16 is, for example, a _SiNx layer with a thickness of 800 nm, and the organic barrier layer 14 is, for example, a thickness of is an acrylic resin layer of less than 100 nm. The thicknesses of the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are each independently 200 nm or more and 1500 nm or less, and the thickness of the organic barrier layer 14 is 50 nm or more and less than 200 nm. The thickness of the TFE structure 10 is preferably 400 nm or more and less than 3 μm, more preferably 400 nm or more and 2.5 μm or less.

The TFE structure 10 is formed to protect the active region (see active region R1 in FIG. 2) of the OLED display device 100, and at least in the active region R1, as described above, sequentially from the side closer to the OLED 3 , a first inorganic barrier layer 12 , an organic barrier layer 14 and a second inorganic barrier layer 16 . The organic barrier layer 14 does not exist as a film covering the entire surface of the active region R1, but has an opening. A portion of the organic barrier layer 14, excluding the opening, where the organic film actually exists will be referred to as a “solid portion”. The organic barrier layer 14 can be formed using, for example, the method described in Patent Document 1 or 2, or a film forming apparatus 200 described later.

In addition, the “opening” (sometimes referred to as “non-solid portion”) does not have to be surrounded by a solid portion, and includes notches and the like. and the second inorganic barrier layer 16 are in direct contact. Hereinafter, a portion where the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are in direct contact is referred to as an "inorganic barrier layer junction".

Next, with reference to FIGS. 2 and 3, the structure and manufacturing method of the OLED display device 100A according to the embodiment of the invention will be described.

FIG. 2 shows a schematic plan view of an OLED display device 100A according to an embodiment of the invention. A cross-sectional structure of the OLED display device 100A will be described with reference to FIGS. 3(a) to (c) and FIGS. 4(a) to (d). 3A and 3B are schematic cross-sectional views of the OLED display device 100A. FIG. 3A is a cross-sectional view along line 3A-3A′ in FIG. ) is a cross-sectional view taken along line 3B-3B' in FIG. FIG. 3(c) is a cross-sectional view showing the taper angle θ of the side surface of each layer. 4A to 4D are schematic cross-sectional views of the OLED display device 100A, FIG. 4A is a cross-sectional view along line 4A-4A′ in FIG. ) is a cross-sectional view along line 4B-4B′ in FIG. 2, FIG. 4C is a cross-sectional view along line 4C-4C′ in FIG. 2, and FIG. FIG. 4D is a cross-sectional view along line 4D-4D′ in FIG.

First, refer to FIG. A circuit 2 formed on a substrate 1 includes a plurality of TFTs (not shown), a plurality of gate bus lines (not shown) and a plurality of source bus lines (not shown) each connected to one of the plurality of TFTs (not shown). and a bus line (not shown). Circuit 2 may be a known circuit for driving multiple OLEDs 3 . A plurality of OLEDs 3 are connected to any of a plurality of TFTs included in circuit 2 . OLED 3 may also be a known OLED.

The circuit 2 further includes a plurality of terminals 34 arranged in a peripheral region R2 outside the active region (the region surrounded by the dashed line in FIG. 2) R1 where the plurality of OLEDs 3 are arranged, and a plurality of terminals 34. It has a plurality of lead-out wirings 32 that connect to either a plurality of gate bus lines or a plurality of source bus lines. The entire circuit 2 including a plurality of TFTs, a plurality of gate bus lines, a plurality of source bus lines, a plurality of lead wirings 32 and a plurality of terminals 34 is sometimes referred to as a drive circuit layer 2 . A portion of the drive circuit layer 2 that is formed within the active region R1 is referred to as a drive circuit layer 2A.

In FIG. 2 and the like, only the lead-out wiring 32 and/or the terminal 34 are sometimes illustrated as components of the drive circuit layer 2. but also has one or more conductive layers, one or more insulating layers and one or more semiconductor layers. The configurations of the conductive layer, the insulating layer, and the semiconductor layer included in the drive circuit layer 2 can be changed, for example, depending on the configurations of TFTs illustrated in FIGS. 9A and 9B. Moreover, an insulating film (base coat) may be formed on the substrate 1 as a base film for the drive circuit layer 2 .

When viewed from the normal direction of the substrate 1, the organic planarizing layer 2Pb is formed in the region in which the inorganic protective layer 2Pa is formed, and the active region R1 is formed in the region in which the organic planarizing layer 2Pb is formed. (2A, 3) are arranged. The outer edge of the TFE structure 10 crosses the plurality of lead wires 32 and exists between the outer edge of the organic planarization layer 2Pb and the outer edge of the inorganic protective layer 2Pa. Therefore, the organic planarizing layer 2Pb is surrounded, together with the OLED layer 3, by the junction where the inorganic protective layer 2Pa and the first inorganic barrier layer 12 are in direct contact (see FIGS. 3(b) and 4(b). ). The inorganic protective layer 2Pa is formed, for example, by plasma CVD using a mask (for example, a metal mask) so as to expose at least a plurality of terminals 34 . Alternatively, once an inorganic protective film is formed by a plasma CVD method so as to cover the terminals 34, patterning is performed by a photolithography process (including a dry etching step) to form openings exposing the terminals 34, thereby forming an inorganic protective film. A protective layer 2Pa may be obtained. As will be described later, when the second inorganic protective layer 2Pa2 is formed on the organic planarizing layer 2Pb (see FIG. 13A), the patterning including the formation of contact holes is performed by the inorganic protective film 2Pa (first inorganic protective layer 2Pa). It is preferable that the protective film 2Pa1), the organic planarization film 2Pb, and the second inorganic protective layer 2Pa2 are collectively treated (see FIG. 14(b)).

The inorganic protective layer 2Pa protects the drive circuit layer 2 . The organic planarization layer 2Pb planarizes the surface of the base on which the OLED layer 3 is formed. The organic planarizing layer 2Pb, like the organic barrier layer 14, has a lower water vapor barrier property than the inorganic protective layer 2Pa and the inorganic barrier layers 12 and 16. Therefore, like the organic planarizing layer 2Pbc of the OLED display device 100C of the comparative example shown in FIGS. 6 to 8, if part of it is exposed to the atmosphere (surrounding atmosphere), it absorbs moisture therefrom. As a result, the organic planarization layer 2Pbc becomes a path for guiding water vapor in the atmosphere into the active region R1. As described above, in the OLED display device 100 according to the embodiment, the organic planarization layer 2Pb is surrounded by the junction where the inorganic protective layer 2Pa and the first inorganic barrier layer 12 are in direct contact, so that the organic planarization Moisture is prevented from being led into the active region R1 from the layer 2Pb.

The organic planarization layer 2Pb is made of, for example, a photosensitive resin. The organic planarization layer 2Pb is formed using various coating methods and printing methods. Moreover, if it has photosensitivity, it is possible to easily form the organic planarization layer 2Pb only in a predetermined region by a photolithography process. For example, after applying a photosensitive resin to almost the entire surface of the element substrate, the photosensitive resin is exposed and developed to form an organic material in a predetermined region (see, for example, FIG. 11B) except for the peripheral portion of the element substrate. A resin film can be formed. If a photosensitive resin is used, contact holes can also be formed by a photolithographic process. The photosensitive resin may be positive or negative. Acrylic resins, epoxy resins, and polyimide resins having photosensitivity can be preferably used. Of course, the organic planarization layer 2Pb can also be formed using a non-photosensitive resin by using a separate photoresist.

Organic resins tend to contain moisture. On the other hand, as described above, OLEDs (particularly organic light-emitting layers and cathode electrode materials) are susceptible to deterioration due to the influence of moisture. Therefore, before forming the OLED layer 3 on the organic planarizing layer 2Pb, it is preferable to heat (bake) the organic planarizing layer 2Pb in order to remove moisture contained therein. The heating temperature is, for example, preferably 100° C. or higher (eg, 1 hour or longer), more preferably 250° C. or higher (eg, 15 minutes or longer). The atmosphere may be atmospheric pressure. By heating in a reduced pressure atmosphere, the heating time can be shortened. A resin material with high heat resistance is preferable, for example, polyimide, so as not to cause thermal deterioration in this heating (baking) step.

Note that the device substrate may be stored or transported before the OLED layer 3 is formed after the organic planarization layer 2Pb is formed. That is, after manufacturing the element substrate on which the drive circuit layer 2, the inorganic protective layer 2Pa, and the organic planarizing layer 2Pb are formed, it takes time to form the OLED layer 3 (for example, it is stored for one day or more and several days). ), or moved to another factory. During this time, as a method for preventing the surface of the organic planarization layer 2Pb from being contaminated or dust from adhering during movement, for example, a positive photoresist film is formed to cover the organic planarization layer 2Pb. do it. This photoresist film is formed by applying a photoresist solution and then pre-baking (solvent volatilization removal: heating for about 5 minutes to about 30 minutes at a temperature range of about 90 ° C. or higher and about 110 ° C. or lower). preferably. After storage or transfer, a clean surface of the organic planarization layer 2Pb can be obtained by removing the photoresist film just before the OLED layer 3 is formed. The photoresist film is preferably removed by exposing the entire surface of the photoresist film and then developing the film without performing normal post-baking, or pre-baking the film, and then stripping the film with a stripping solution without exposing the entire surface. . As a material for forming a positive photoresist film, for example, OFPR-800 manufactured by Tokyo Ohka Co., Ltd., which is a positive photoresist, can be suitably used.

As will be described later with reference to FIG. 11(a), a bank layer may be formed during the process of forming the OLED layer 3. FIG. The bank layer is formed after forming the lower electrode and before forming the organic layer (organic EL layer). Since the bank layer is made of an organic resin (for example, polyimide), it easily absorbs moisture and is in contact with the organic layer. Therefore, it is preferable to heat the bank layer to remove moisture. Therefore, after forming the organic planarizing layer 2Pb, forming the lower electrode and forming the bank layer, a positive photoresist film for protecting the surface of the element substrate may be formed as described above. good. After the necessary storage and/or transportation, the photoresist film is removed as described above, and the moisture contained in the organic planarizing layer 2Pb and the bank layer is removed by heating immediately before forming the organic layer. Thus, the heating process for removing moisture contained in the organic planarizing layer 2Pb may serve as the heating process for removing moisture contained in the bank layer. Of course, as described above, after the organic planarizing layer 2Pb is protected with a positive photoresist film and the positive photoresist film is removed, a heating process is performed to remove moisture contained in the organic planarizing layer 2Pb. After that, after forming the lower electrode and the bank layer, and before forming the organic layer, a heating step for removing moisture contained in the bank layer may be performed.

Next, the cross-sectional structure of the OLED display device 100A will be described in more detail with reference to FIGS. 3(a) to (c) and FIGS. 4(a) to (d).

As shown in FIGS. 3(a), (b) and FIGS. 4(a), (b), the TFE structure 10A includes the first inorganic barrier layer 12 formed on the OLED 3 and the first inorganic barrier layer 12. It has a contacting organic barrier layer 14 and a second inorganic barrier layer 16 contacting the organic barrier layer 14 . The first inorganic barrier layer 12 and the second inorganic barrier layer 16 are, for example, SiN _x layers, and are selectively formed only in predetermined regions so as to cover the active region R1 by plasma CVD using a mask. .

The organic barrier layer 14 can be formed, for example, by the method described in Patent Document 2 or 3 above. For example, in a chamber, a vapor or mist of an organic material (for example, an acrylic monomer) is supplied onto an element substrate maintained at a temperature below room temperature, condensed on the element substrate, and becomes a liquid organic material. Due to capillarity or surface tension of the material, the first inorganic barrier layer 12 is unevenly distributed at the boundary between the side surface of the convex portion and the flat portion. After that, by irradiating the organic material with, for example, ultraviolet rays, a solid portion of the organic barrier layer (for example, an acrylic resin layer) 14 is formed on the boundary portion around the convex portion. The organic barrier layer 14 formed by this method has substantially no solid portion in the flat portion. Regarding the method of forming the organic barrier layer, the disclosures of Patent Documents 2 and 3 are incorporated herein by reference.

The organic barrier layer 14 is also formed by adjusting the initial thickness of the resin layer formed using the film forming apparatus 200 (for example, less than 100 nm) and/or by ashing the once-formed resin layer. , can also be formed. The ashing treatment can be performed, for example, by plasma ashing using at least one of N ₂ O, O ₂ and O ₃ gases, as will be detailed later.

FIG. 3(a) is a cross-sectional view taken along line 3A-3A' in FIG. 2 and shows a portion including particles P. FIG. The particles P are fine dust generated during the manufacturing process of the OLED display device, such as fine glass fragments, metal particles, and organic particles. Particles are particularly likely to occur when the mask vapor deposition method is used.

As shown in FIG. 3A, the organic barrier layer (solid portion) 14 can be formed only around the particles P. As shown in FIG. This is because the acrylic monomer applied after forming the first inorganic barrier layer 12 is condensed and unevenly distributed around the surface (taper angle θ of 90° or more) of the first inorganic barrier layer 12a on the particles P. is. An opening (non-solid portion) of the organic barrier layer 14 is formed on the flat portion of the first inorganic barrier layer 12 .

Cracks (defects) 12 c may be formed in the first inorganic barrier layer 12 when particles (for example, having a diameter of approximately 1 μm or more) P are present. It is considered that this is caused by impingement between the SiN _{x layer 12 a growing from the surface of the particle P and the SiN x layer} 12 b growing from the flat portion of the surface of the OLED 3 . The presence of such cracks 12c reduces the barrier properties of the TFE structure 10A.

In the TFE structure 10A of the OLED display device 100A, as shown in FIG. The surface connects the surface of the first inorganic barrier layer 12a on the particles P and the surface of the first inorganic barrier layer 12b on the flat portion of the OLED 3 continuously and smoothly. Therefore, a dense film is formed without forming defects in the first inorganic barrier layer 12 on the particles P and the second inorganic barrier layer 16 formed on the organic barrier layer 14 . Thus, the organic barrier layer 14 can maintain the barrier properties of the TFE structure 10A even when the particles P are present.

Next, referring to FIG. 3(b) and FIGS. 4(a) to (d), the cross-sectional structure on the lead wire 32 and the terminal 34 will be described.

As shown in FIG. 3B, lead wires 32 and terminals 34 are integrally formed on the substrate 1, and an inorganic protective layer 2Pa is formed on the lead wires 32 so as to expose the terminals 34. ing. An organic planarization layer 2Pb is formed on the inorganic protective layer 2Pa, and an OLED layer 3 is formed on the organic planarization layer 2Pb. The TFE structure 10A is formed to cover the OLED layer 3 and the organic planarization layer 2Pb, and the OLED layer 3 and the organic planarization layer 2Pb are in direct contact with the inorganic protective layer 2Pa and the first inorganic barrier layer 12. Surrounded by junctions. Note that the organic barrier layer (solid portion) 14 between the first inorganic barrier layer 12 and the second inorganic barrier layer 16 of the TFE structure 10A is formed only around convex portions such as particles, so here Not shown. The organic barrier layer (solid portion) 14 is surrounded by an inorganic barrier layer junction where the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are in direct contact.

As shown in FIG. 4A, in a region near the active region R1 (cross section along line 4A-4A′ in FIG. 2), on the lead wire 32, an inorganic protective layer 2 Pa and an organic planarizing layer 2Pb and TFE structures 10A are formed.

As shown in FIG. 4B, in the cross section along line 4B-4B' in FIG. 2, the inorganic protective layer 2Pa and the first inorganic barrier layer 12 are in direct contact, and the organic planarizing layer 2Pb is surrounded by a junction where the inorganic protective layer 2Pa and the first inorganic barrier layer 12 are in direct contact (see FIGS. 2 and 3(b)).

As shown in FIG. 4(c), only the inorganic protective layer 2Pa is formed on the lead wire 32 in the region near the terminal 34. As shown in FIG.

As shown in FIG. 4D, the terminals 34 are also exposed from the inorganic protective layer 2Pa and used for electrical connection with external circuits (for example, FPC (Flexible Printed Circuits)).

4(b) to 4(d) are not covered with the organic planarization layer 2Pb. part) can be formed. For example, if the side surface of the lead wire 32 in cross section parallel to the line width direction has a taper angle θ of 90° or more, the organic barrier layer can be formed along the side surface of the lead wire 32 . However, as shown in FIGS. 4(b) to 4(d), in the OLED display device 100A according to the embodiment, at least in these regions, the taper angle θ of the side surface in the cross-sectional shape of the lead wire 32 and the terminal 34 is 90°. It is less than that, and the photocurable resin is not unevenly distributed. Therefore, no organic barrier layer (solid portion) is formed along the side surfaces of the lead-out wiring 32 and the terminal 34 .

Here, the taper angle θ of the side surface of each layer will be described with reference to FIG. 3(c). FIG. 3(c) is a cross-sectional view showing the taper angle θ of the side surface of each layer, and corresponds to the cross-sectional view shown in FIG. 4(b), for example. As shown in FIG. 3C, the taper angle θ of the side surface in the cross-sectional shape parallel to the width direction of the lead wire 32 is expressed as θ(32), and similarly the taper angle θ of the side surface of the other layers is θ( (reference numerals of the components).

Then, the inorganic protective layer 2Pa formed on the lead wire 32, the side surfaces of the first inorganic barrier layer 12 and the side surface of the second inorganic barrier layer 16 of the TFE structure 10A formed on the inorganic protective layer 2Pa are tapered. The angle θ satisfies the relationship θ(32)≧θ(2Pa)≧θ(12)≧θ(16). Therefore, if the taper angle θ (32) of the side surface of the lead wire 32 is less than 90°, the taper angle θ (2 Pa) of the side surface of the inorganic protective layer 2 Pa and the taper angle θ (12 Pa) of the side surface of the first inorganic barrier layer 12 ) is also less than 90°.

When the taper angle θ of the side surface is 90° or more, in the method for forming an organic barrier layer described in Patent Document 2 or 3, along the boundary (with an angle of 90° or less) between the side surface and the flat surface, Vapor or mist of organic material (eg, acrylic monomer) will condense to form an organic barrier layer (solid portion). Then, for example, the organic barrier layer (solid portion) formed along the lead-out wiring becomes a path for guiding water vapor in the atmosphere into the active region.

For example, as shown in the schematic cross-sectional view corresponding to FIG. 4B in the OLED display device 100B1 of the comparative example in FIG. When the taper angle θ (12B1) of the side surface of the barrier layer 12B1 is 90° or more, the first inorganic barrier layer 12B1 and the second inorganic barrier layer 16B1 are formed along the side surface of the first inorganic barrier layer 12B1 of the TFE structure 10B1. An organic barrier layer (solid portion) 14B1 is formed therebetween. Note that the OLED display device 100B1, for example, omits the inorganic protective layer 2Pa in the OLED display device 100 according to the embodiment, and the taper angle θ (32) of the side surface of the lead wiring 32 and the The taper angle θ(12) may be changed to 90° or more.

Further, as shown in the schematic cross-sectional view corresponding to FIG. 4B in the OLED display device 100B2 of the comparative example in FIG. When the taper angles θ(32B2), θ(2PaB2), and θ(12B2) of the side surfaces are 90° or more, the first inorganic barrier layer 12B2 and the second 2 An organic barrier layer (solid portion) 14B2 is formed between the two inorganic barrier layers 16B2. In the OLED display device 100B2, for example, the side taper angle θ(32) of the lead wire 32 and the side taper angle θ(12) of the first inorganic barrier layer 12 in the OLED display device 100A according to the embodiment are changed to 90° or more. It may be

Unlike the OLED display device 100B1, the OLED display device 100B2 has the inorganic protective layer 2PaB2. Therefore, the side taper angle θ (12B2) of the first inorganic barrier layer 12B2 is It tends to be smaller than the side taper angle θ (12B1) of 12B1.

Taper angles θ(32), θ( 2Pa) and θ(12) are both less than 90°, and the organic barrier layer 14 is not formed along these sides. Therefore, moisture in the atmosphere does not reach the active region R1 through the organic barrier layer (solid portion) 14, and excellent humidity resistance reliability can be obtained. Although an example in which the taper angles θ(32), θ(2Pa) and θ(12) are all less than 90° is shown here, the present invention is not limited to this, and at least the surface immediately below the organic barrier layer 14 is composed of If the taper angle θ (12) of the side surface of the first inorganic barrier layer 12 to the side surface is less than 90°, the laminated structure shown in FIG. (no organic planarization layer 2Pb is present) and a portion where the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are in direct contact (no organic barrier layer 14 is present) are formed. Therefore, it is possible to suppress/prevent moisture in the air from entering the active region R1 via the organic planarization layer 2Pb or the organic barrier layer 14. In addition, by having the inorganic protective layer 2Pa, the second Since the taper angle θ(12) of the first inorganic barrier layer 12 can be reduced, even if the taper angle θ(32) of the lead wire 32 is relatively large (for example, 90°), the first inorganic barrier layer 12 The taper angle θ(12) can be less than 90°, that is, the taper angle θ(32) of the lead wire 32 can be 90° or close to 90°, so the L/S of the lead wire 32 can be reduced. You get the advantage of being able to

When the taper angle θ of the side surface is in the range of 70° or more and less than 90°, the organic barrier layer (solid portion) 14 may be formed along the side surface. Of course, if the ashing process is performed, the resin unevenly distributed along the inclined side surface can be removed, but the time required for the ashing process is lengthened. For example, a long ashing process is required even after removing the resin formed on the flat surface. Alternatively, as a result of excessive ashing (removal) of the organic barrier layer (solid portion) formed around the particles P, a problem may occur in which the effect of forming the organic barrier layer is not sufficiently exhibited. In order to suppress or prevent this, the taper angle θ(12) of the first inorganic barrier layer 12 is preferably less than 70°, more preferably less than 60°.

Next, the structure of the OLED display device 100C of the comparative example will be described with reference to FIGS. 6 to 8. FIG. FIG. 6 shows a schematic plan view of the OLED display device 100C. 7A and 7B are schematic cross-sectional views of the OLED display device 100C, FIG. 7A is a cross-sectional view along line 7A-7A′ in FIG. ) is a cross-sectional view taken along line 7B-7B' in FIG. 8A to 8C are schematic cross-sectional views of the OLED display device 100C, FIG. 8A is a cross-sectional view along line 8A-8A' in FIG. ) is a sectional view taken along line 8B-8B' in FIG. 6, and FIG. 8(c) is a sectional view taken along line 8C-8C' in FIG.

The OLED display device 100C differs from the OLED display device 100 according to the embodiment in that it does not have the inorganic protective layer 2Pa and that the organic planarization layer 2Pbc extends to the region not covered by the TFE structure 10C. . Components that are substantially the same as those of the OLED display device 100A are denoted by the same reference numerals, and description thereof may be omitted.

For example, as is clear from FIGS. 6, 7B, and 8B, part of the organic planarization layer 2Pbc is exposed to the atmosphere (surrounding atmosphere). As a result, the organic planarization layer 2Pbc absorbs moisture from the portion exposed to the atmosphere, and becomes a path for guiding water vapor in the atmosphere into the active region R1. On the other hand, in the OLED display device 100A according to the embodiment, as shown in FIGS. It is surrounded by a junction in direct contact with the barrier layer 12 . Therefore, the above problem of the OLED display device 100C of the comparative example can be solved.

Next, with reference to FIGS. 9 and 10, an example of a TFT used in an OLED display device 100A and an example of lead wires and terminals formed using a gate metal layer and a source metal layer when manufacturing the TFT are shown. explain. The structures of TFTs, lead wires, and terminals, which will be described below, can be used in the OLED display device 100A of the above-described embodiment.

Low-temperature polysilicon (abbreviated as "LTPS") TFTs or oxide TFTs (e.g., In (indium), Ga (gallium), Zn (zinc ) and O (oxygen) (In--Ga--Zn--O system) oxide TFT) is preferably used. Since the structures and manufacturing methods of LTPS-TFTs and In--Ga--Zn--O-based TFTs are well known, only a brief description will be given below.

FIG. 9(a) is a schematic cross-sectional view of the LTPS _{- TFT2PT} , which can be included in the circuit 2 of the OLED display device 100A. The LTPS-TFT2 _P T is a top-gate type TFT.

The TFT 2 _P T is formed on a base coat 2 _PP on a substrate (eg polyimide film) 1 . Although omitted in the above description, it is preferable to form a base coat made of an inorganic insulator on the substrate 1 .

The TFT _2PT is formed on the polysilicon layer _2Pse formed on the base coat _2Pp , the gate insulating layer _2Pgi formed on the polysilicon layer _2Pse , and the gate insulating layer _2Pgi . a gate electrode _2Pg , an interlayer insulating layer _2Pi formed on the gate electrode _2Pg , and a source electrode _2Pss and a drain electrode _2Psd formed on the interlayer insulating layer _2Pi . have. The source electrode _2Pss and the drain electrode _2Psd are connected to the source region and the drain region of the polysilicon layer _2Pse in contact holes formed in the interlayer insulating layer _2Pi and the gate insulating layer _2Pgi , respectively. It is

The gate electrode _2Pg is included in the same gate metal layer as the gate bus lines, and the source electrode _2Pss and the drain electrode _2Psd are included in the same source metal layer as the source bus lines. Using the gate metal layer and the source metal layer, lead wires and terminals are formed (described later with reference to FIG. 10).

The _TFT2PT is manufactured, for example, as follows.

As the substrate 1, for example, a polyimide film having a thickness of 15 μm is prepared.

A base coat 2 _Pp (SiO ₂ film: 250 nm/SiN _x film: 50 nm/SiO ₂ film: 500 nm (upper layer/intermediate layer/lower layer)) and an a-Si film (40 nm) are formed by plasma CVD.

A dehydrogenation treatment (eg, annealing at 450° C. for 180 minutes) is performed on the a-Si film.

The a-Si film is polysiliconized by excimer laser annealing (ELA).

An active layer (semiconductor island) is formed by patterning the a-Si film by a photolithography process.

A gate insulating film (SiO ₂ film: 50 nm) is deposited by plasma CVD.

A channel region of the active layer is doped (B ⁺ ).

A gate metal (Mo: 250 nm) film is formed by a sputtering method, and patterned by a photolithography process (including a dry etching process) (to form a gate electrode _2Pg , a gate bus line, etc.).

Doping (P ⁺ ) is performed on the source and drain regions of the active layer.

Activation annealing (eg, annealing at 450° C. for 45 minutes) is performed. A polysilicon layer _2Pse is thus obtained.

An interlayer insulating film (for example, SiO ₂ film: 300 nm/SiN _x film: 300 nm (upper layer/lower layer)) is formed by plasma CVD.

A contact hole is formed in the gate insulating film and the interlayer insulating film by dry etching. Thus, the interlayer insulating layer 2 _P i and the gate insulating layer 2 _P gi are obtained.

A source metal (Ti film: 100 nm/Al film: 300 nm/Ti film: 30 nm) is formed by sputtering, and patterned by a photolithography process (including a dry etching process) (source electrode 2 _P ss, drain electrode 2 _P ss). sd and source bus lines, etc.).

After that, the above inorganic protective layer 2Pa (see FIGS. 2 and 3) is formed by plasma CVD, for example.

FIG. 9B is a schematic cross-sectional view of an In--Ga--Zn-- _O based TFT _2.sub.OT , which can be included in the circuit 2 of the OLED display device 100A. The _TFT2OT is a bottom gate type TFT.

The TFT 2 _O T is formed on a base coat 2 _O p on a substrate (eg polyimide film) 1 . The TFT _2OT is formed on the gate electrode _20g formed on the base coat _20p , the gate insulating layer _20gi formed on the gate electrode _20g , and the gate insulating layer _20gi . It has an oxide semiconductor layer 2 _{0 se} , and a source electrode 2 0 ss and a drain electrode 2 _{0 sd} respectively connected to the source region and the drain region of the oxide semiconductor layer 2 0 se. The source electrode 2 0 _ss and the drain electrode 2 0 _sd are covered with an interlayer insulating layer 2 ₀ i.

The gate electrode _20g is included in the same gate metal layer as the gate bus line, and the source electrode _20ss and the drain electrode _20sd are included in the same source metal layer as the source bus line. Using the gate metal layer and the source metal layer, lead wires and terminals are formed and may have a structure described later with reference to FIG.

The _TFT2OT is manufactured, for example, as follows.

As the substrate 1, for example, a polyimide film having a thickness of 15 μm is prepared.

_A base coat 20p (SiO ₂ film: 250 nm/SiN _x film: 50 nm/SiO ₂ film: 500 nm (upper layer/intermediate layer/lower layer)) is formed by plasma CVD.

A gate metal (Cu film: 300 nm/Ti film: 30 nm (upper layer/lower layer)) is formed by a sputtering method, and patterned by a photolithography process (including a dry etching process) (gate electrodes 20 _g , gate bus lines, etc.). ).

A gate insulating film (SiO ₂ film: 30 nm/SiN _x film: 350 nm (upper layer/lower layer)) is formed by plasma CVD.

An active layer (semiconductor island) is formed by forming an oxide semiconductor film (In-Ga-Zn-O-based semiconductor film: 100 nm) by a sputtering method and patterning it by a photolithography process (including a wet etching process). do.

A source metal (Ti film: 100 nm/Al film: 300 nm/Ti film: 30 nm (upper layer/intermediate layer/lower layer)) is formed by sputtering and patterned by a photolithography process (including a dry etching process) (source electrode 2 _{0 ss} , drain electrode 2 0 _sd and source bus lines, etc.).

Activation annealing (for example, annealing at 300° C. for 120 minutes) is performed. Thus, the oxide semiconductor layer 2 _Ose is obtained.

Thereafter, an interlayer insulating layer _20i (for example, SiN _x film: 300 nm/SiO ₂ film: 300 nm (upper layer/lower layer)) is formed as a protective film by plasma CVD. This interlayer insulating layer 20i can also serve as the inorganic protective layer _2Pa (see FIGS. 2 and 3). Of course, an inorganic protective layer 2Pa may be further formed on the interlayer insulating layer _2Oi .

Next, structures of other OLED display devices according to embodiments will be described with reference to FIGS. The circuit (backplane) 2 of this OLED display device has the _TFT2PT shown in FIG. _9A or the _{TFT2OT shown} in FIG. A lead-out wiring 32A and a terminal 34A are formed using the original gate metal layer and source metal layer. FIGS. 10(a)-(c) correspond to FIGS. 4(b)-(d), respectively, and the reference numerals of the corresponding components are denoted by "A". Also, the base coat 2p in FIG. 10 corresponds to the base coat 2 _P p in FIG. 9A and the base coat 2 _O p in FIG. 9B, and the gate insulating layer 2gi in FIG. a) and the gate insulating layer _20gi in FIG. 9(b), and the interlayer insulating layer _2i in FIG. 10 corresponds to the interlayer insulating layer _2Pgi in FIG. 9(a). i and the interlayer insulating layer 2 _o i in FIG. 9(b), respectively.

As shown in FIGS. 10A to 10C, the gate metal layer 2g and the source metal layer 2s are formed on the base coat 2p formed on the substrate 1. As shown in FIGS. Although omitted in FIGS. 3 and 4, it is preferable to form a base coat 2p made of an inorganic insulator on the substrate 1. As shown in FIG.

As shown in FIGS. 10(a) to 10(c), the lead wiring 32A and the terminal 34A are formed as a laminate of the gate metal layer 2g and the source metal layer 2s. The portion of the lead wire 32A and the terminal 34A formed of the gate metal layer 2g has, for example, the same cross-sectional shape as that of the gate bus line, and the portion of the lead wire 32A and the terminal 34A formed of the source metal layer 2s is, for example, the source. It has the same cross-sectional shape as the bus line. For example, in the case of a 500 ppi 5.7-inch display device, the line width of the portion formed of the gate metal layer 2g is, for example, 10 μm, the adjacent distance is 16 μm (L/S=10/16), and the source metal The line width of the portion formed by the layer 2s is, for example, 16 μm, and the distance between adjacent portions is 10 μm (L/S=16/10). The taper angles θ are all less than 90°, preferably less than 70°, more preferably 60° or less. The taper angle of the portion formed under the organic planarization layer Pb may be 90° or more.

Next, still another embodiment according to the present invention will be described with reference to FIGS. 11 to 14. FIG. According to the following embodiments, an organic EL device capable of improving luminous efficiency and a manufacturing method thereof are provided. Note that the OLED display device exemplified in the following embodiments has the structure of the OLED display device according to the above-described embodiment, and is improved in mass productivity and humidity resistance reliability, but is independent of the above-described embodiment. In addition, the luminous efficiency can be improved.

The OLED display device of the embodiments described below includes a substrate, a plurality of TFTs formed on the substrate, a plurality of gate bus lines and a plurality of source bus lines each connected to one of the plurality of TFTs. a driver circuit layer having a plurality of terminals and a plurality of lead wirings connecting the plurality of terminals to either the plurality of gate bus lines or the plurality of source bus lines; and an interlayer insulation formed on the driver circuit layer. an organic EL element layer formed on the interlayer insulating layer and having a plurality of organic EL elements each connected to one of the plurality of TFTs; and a thin film encapsulant formed to cover the organic EL element layer. structure. The interlayer insulating layer has a contact hole, and a contact portion for connecting the driving circuit layer and the organic EL element layer is formed in the contact hole. 1, and the arithmetic mean roughness Ra is 50 nm or less.

That is, since the arithmetic mean roughness Ra of the surface on which the OLED layer is formed is 50 nm or less, the luminous efficiency is improved. Furthermore, since the arithmetic average roughness Ra of the surface of the contact portion is also 50 nm or less, the luminous efficiency does not decrease even if the contact portion is arranged in the pixel. Therefore, since it is not necessary to form pixels while avoiding the contact portion, the degree of freedom in design is increased, and the area ratio of the pixels can be improved.

A conductive contact film that forms a contact portion, that is, a contact film that fills a contact hole in an interlayer insulating film is formed of a material different from that of the lower electrode, for example. For example, it is a laminated film of a titanium film and a copper film. The titanium film is formed by sputtering, for example, and the copper film is formed on the titanium film by plating. For example, it can be formed by electroplating using a titanium film as a power supply layer.

By subjecting the surface of the contact film and the surface of the interlayer insulating film to chemical mechanical polishing, surfaces having an arithmetic mean roughness Ra of 50 nm or less can be obtained.

For example, the interlayer insulating layer has a first inorganic protective layer formed on the drive circuit layer and exposing at least the plurality of terminals, and an organic planarizing layer formed on the first inorganic protective layer, and includes an organic planarizing layer. The arithmetic mean roughness Ra of the surface of the coating layer is 50 nm or less (see FIG. 11).

Alternatively, the interlayer insulating layer comprises a first inorganic protective layer formed on the drive circuit layer and exposing at least a plurality of terminals, an organic planarizing layer formed on the first inorganic protective layer, and an organic planarizing layer formed on the organic planarizing layer. and the arithmetic mean roughness Ra of the surface of the second inorganic protective layer is 50 nm or less (see FIG. 13).

11-14, another OLED display structure and manufacturing method according to another embodiment of the present invention will be described. The OLED display device 100D shown in FIG. 11 and the OLED display device 100E shown in FIG. 13 have the LTPS- _TFT2PT shown in FIG. 9(a). Of course, instead of the LTPS-TFT 2 _P T, the In--Ga--Zn--O system TFT 2 _O T shown in FIG. 9B can be used, or other known TFTs can be used. 11(a) and 13(a) also show the common wiring 2 _P c and the contact portion 2 _P cv electrically connected to the upper electrode (common electrode) 46 of the OLED. there is

First, refer to FIGS. 11 and 12. FIG. 11A and 11B are schematic cross-sectional views of the OLED display device 100D, and FIGS. It is a sectional view.

An OLED display device 100D shown in FIG. 11A includes a driver circuit layer 2 having a plurality of TFTs and the like formed on a substrate 1, an interlayer insulating layer formed on the driver circuit layer 2, and a and a thin-film sealing structure 10</b>D formed to cover the organic EL element layer 3 . The interlayer insulating layer here includes an inorganic protective layer 2Pa and an organic planarizing layer 2Pb formed on the inorganic protective layer 2Pa. The interlayer insulating layers, that is, the inorganic protective layer 2Pa and the organic planarizing layer 2Pb have contact holes CH1 and CH2, and contact holes CH1 and CH2 for connecting the drive circuit layer 2 and the organic EL element layer 3 are provided in the contact holes CH1 and CH2. Parts C1 and C2 are formed. The surface 2Pb_Sb of the organic planarization layer 2Pb and the surfaces C_Sb of the contact portions C1 and C2 are flush with each other, and have an arithmetic mean roughness Ra of 50 nm or less.

An OLED layer 3 is formed on the organic planarization layer 2Pb. A lower electrode and an organic layer (also referred to as an organic EL layer, including at least an organic light-emitting layer) of the OLED 3 are required to have high flatness. If the flatness is low, for example, the luminous efficiency of the OLED 3 is lowered. The organic planarization layer 2Pb is formed from a liquid organic resin material (which may contain a solvent) applied to the surface of the element substrate (which will be called the element substrate for simplicity during manufacturing). It is possible to absorb irregularities (steps) of the base of the planarizing layer 2Pb and form a flat surface. However, the surface of an organic resin film formed from a liquid resin material has roughness (which can be expressed as “undulation”) with an arithmetic mean roughness Ra exceeding 100 nm and up to about 300 nm (FIG. 12). (a)). If the OLED 3 is formed on the organic planarization layer 2Pb having such surface roughness, the luminous efficiency cannot be sufficiently improved. For example, even if a microresonator structure is adopted, there is a problem that its effect cannot be sufficiently exhibited.

Furthermore, when the lower electrode and the organic layer are formed over the contact hole CH1 of the organic planarization layer 2Pb, a depression (concave portion) may be formed in the lower electrode and the organic layer positioned immediately above the contact hole CH1. If the contact hole CH1 is provided outside the pixel Pix, this problem can be avoided, but the area ratio of the pixel is reduced.

Therefore, in the OLED display device 100D, the surface 2Pb_Sb of the organic planarization layer 2Pb and the surfaces C_Sb of the contact portions C1 and C2 are flush with each other, and the arithmetic mean roughness Ra is 50 nm or less.

Now, refer to FIGS. 12(a) to 12(c).

FIG. 12(a) schematically shows a state immediately after forming an inorganic protective film 2Pa to be the inorganic protective layer 2Pa on the drive circuit layer 2 and then forming an organic planarizing film 2Pb to be the organic planarizing layer 2Pb. shown in The thickness of the inorganic protective layer 2Pa is, for example, 100 nm or more and 1000 nm or less. The thickness of the organic planarization film 2Pb is, for example, 1000 nm or more and 5000 nm or less. The inorganic protective film 2Pa is selectively deposited on a desired region using a metal mask. Further, the organic planarizing film 2Pb is selectively formed by coating on a desired region of the element substrate 20, or once formed on the entire surface, and then an unnecessary portion is removed. The inorganic protective film 2Pa is different from the inorganic protective layer 2Pa in that it does not have openings such as contact holes CH1 and CH2, but is indicated by the same reference numerals for the sake of simplicity. Similarly, the organic planarization film 2Pb is different from the organic planarization layer 2Pb in that it does not have openings such as contact holes CH1 and CH2, but is indicated by the same reference numerals for the sake of simplicity.

The surface 2Pb_Sa of the organic planarization film 2Pb immediately after being formed has roughness with an arithmetic mean roughness Ra exceeding 100 nm and up to about 300 nm. As shown in FIG. 12B, contact holes CH1 and CH2 are formed by patterning the inorganic protective film 2Pa and the organic planarizing film 2Pb. This patterning can be performed, for example, by dry etching using a mixed gas of O ₂ and CF ₄ . In addition, as shown in FIG. 11B, only the inorganic protective layer 2Pa is formed in order to form a portion where the inorganic protective layer 2Pa and the first inorganic barrier layer (not shown) constituting the TFE structure 10D are in direct contact. The remaining portion can be formed, for example, by using a multi-tone mask.

When the conductive contact film C is formed on the patterned organic planarization film 2Pb, the surface C_Sa of the contact film C has a surface roughness reflecting the surface roughness of the surface 2Pb_Sa of the organic planarization film 2Pb. become. The contact film C includes, for example, a titanium (Ti) film Ca and a copper (Cu) film Cb formed on the titanium film Ca. The titanium film Ca is formed by sputtering, for example, and the copper film Cb is formed by plating, for example. From the viewpoint of mass productivity, it is preferable to form the copper film Cb by electroplating using the titanium film Ca as a power supply layer. The thickness of the titanium film Ca is, for example, 5 nm or more and 150 nm or less, more preferably 10 nm or more and 100 nm or less. The thickness of the copper (Cu) film Cb is, for example, 1000 nm or more and 3000 nm or less, more preferably 1500 nm or more and 2500 nm or less.

Next, as shown in FIG. 12(c), the surface 2Pb_Sa of the organic planarizing film 2Pb and the surface C_Sa of the contact film C are subjected to chemical mechanical polishing to obtain a smooth surface of the organic planarizing layer 2Pb and the contact portion. C1 and C2 are obtained. The contact portions C1 and C2 respectively have C11 and C21 formed from a titanium film Ca and C12 and C22 formed from a copper film Cb. The surface 2Pb_Sb of the organic planarization layer 2Pb and the surface C_Sb of the contact layer C are flush with each other and have an arithmetic mean roughness Ra of 50 nm or less.

By subjecting the surface 2Pb_Sa of the organic planarizing film 2Pb and the surface C_Sa of the contact film C (both Ra>50 nm) shown in FIG. and the surface C_Sb can be obtained. The arithmetic mean roughness Ra of the surface 2Pb_Sb and the surface C_Sb of the contact film C is preferably 30 nm or less. The arithmetic mean roughness Ra is preferably as small as possible, and there is no lower limit value. However, considering the relationship between the cost and time required for CMP and the effect, the arithmetic mean roughness Ra may be 10 nm or more, and may be 20 nm or more. may be

Specifically, CMP may be performed using a slurry containing an oxidizing agent such as hydrogen peroxide, an organic acid such as citric acid, or an amino acid such as glycine, and a fumed silica-based or colloidal silica-based abrasive. Even if such an acid-based chemical solution is used, it does not erode the polyimide substrate. A slurry containing alumina (Al ₂ O ₃ ) powder may also be used. The load of the polishing pad is preferably 50 g/cm ² or more and 150 g/cm ² or less, and the rotation speed is preferably 20 rpm or more and 40 rpm or less. The polishing time is about 30 seconds to about 90 seconds.

In the OLED display device according to the embodiment of the present invention, the level of smoothing required to suppress a decrease in luminous efficiency is about one order lower than the level of smoothing required for photoprocessing of VLSI ( The value of the arithmetic mean roughness Ra is about 10 times larger), so a wide range of known abrasives used for CMP of copper wiring in semiconductor processes can be used.

Surface roughness can be measured using, for example, a confocal laser microscope or an atomic force microscope (AFM). The measurement range preferably includes the vicinity of the center of the pixel, and the reference length is appropriately set according to the surface roughness.

In this specification, planarization by CMP is sometimes referred to as "smoothing" in order to distinguish between planarization by the organic planarization layer 2Pb and planarization by CMP.

Since the arithmetic mean roughness Ra of the surface on which the OLED layer 3 is formed is 50 nm or less, the luminous efficiency is improved. Furthermore, since the arithmetic mean roughness Ra of the surface C_Sb of the contact portions C1 and C2 is also 50 nm or less, the luminous efficiency does not decrease even if the contact portion C1 is arranged within the pixel Pix. Therefore, since it is not necessary to form the pixel Pix while avoiding the contact portion C1, the degree of freedom in design is increased, and the area ratio of the pixel Pix can be improved.

Please refer to FIG. 11 again.

Next, on the surface 2Pb_Sb of the organic planarization film 2Pb and the surface C_Sb of the contact film C, the lower electrode 42 and the upper electrode contact portion 43 are formed. The lower electrode 42 is electrically connected to the drain electrode 2 _Psd via the contact portion C1. The lower electrode 42 has, for example, a silver (Ag) layer and an ITO layer formed on the silver (Ag) layer. Ag is preferable because it easily forms an alloy with Cu (the main constituent element of the contact portion C1) and can make the contact resistance almost zero. In the conventional structure in which the contact portion C1 is not formed, the metal forming the drain electrode 2 _P sd is in contact with the ITO layer in the contact hole CH1. You can also get the effect of lowering. The thickness of the silver layer is, for example, 50 nm or more and 150 nm or less, and the thickness of the ITO layer is, for example, 5 nm or more and 15 nm or less.

Next, a bank layer 48 that defines each of the plurality of pixels Pix is formed. The bank layer 48 has an opening corresponding to the pixel Pix, and the side surface of the opening has an inclined surface with forward tapered side portions. The slope of the bank layer 48 surrounds each pixel. The bank layer 48 is formed using, for example, a photosensitive resin (such as polyimide or acrylic resin). The thickness of the bank layer 48 is, for example, 1 μm or more and 2 μm or less. The inclination angle of the slope of the bank layer 48 is 60° or less. If the inclination angle θb of the slope of the bank layer 48 exceeds 60°, defects may occur in the layer positioned above the bank layer 48 .

As described above, it is preferable to heat (bake) in order to remove moisture contained in the bank layer 48 and moisture contained in the organic planarization layer 2Pb. The heating temperature is, for example, preferably 100° C. or higher (eg, 1 hour or longer), more preferably 250° C. or higher (eg, 15 minutes or longer). The atmosphere may be atmospheric pressure. By heating in a reduced pressure atmosphere, the heating time can be shortened. The bank layer 48 and the organic planarizing layer 2Pb are preferably made of a highly heat-resistant resin material, such as polyimide, so that thermal deterioration does not occur in this heating (baking) step. is preferred.

After that, the manufacturing of the element substrate may be interrupted and the element substrate may be stored or transported. In that case, as described above, a positive photoresist film may be formed to cover the surface of the element substrate formed up to the bank layer 48 . After storage or transfer, a clean surface can be obtained by removing the photoresist film just prior to forming the organic layer 44 . Also, just before the formation of the organic layer 44, the moisture contained in the organic planarization layer 2Pb and the bank layer 48 is removed by heating.

Next, an organic layer 44 is formed on the lower electrode 42 . The organic layer 44 is formed by vapor deposition, for example. An upper electrode 46 is formed over the organic layer 44 . The upper electrode 46 is in contact with the upper electrode contact portion 43 and is electrically connected to the common wiring 2 _Pc via the contact portion 2 _P cv.

Lower electrode 42 and upper electrode 46 constitute, for example, an anode and a cathode, respectively. The upper electrode 46 is a common electrode formed over the entire pixels in the active region, and the lower electrode (pixel electrode) 42 is formed for each pixel. If the bank layer 48 exists between the lower electrode 42 and the organic layer 44 , holes are not injected from the lower electrode 42 into the organic layer 44 . Therefore, since the region where the bank layer 48 exists does not function as the pixel Pix, the bank layer 48 defines the outer edge of the pixel Pix. The bank layer 48 is also called PDL (Pixel Defining Layer).

After forming the OLED 3 in this way, the TFE structure 10D is formed. TFE structure 10D has a structure similar to TFE structure 10A described above. That is, the TFE structure 10D has a first inorganic barrier layer (eg SiN _x layer) 12, an organic barrier layer 14, and a second inorganic barrier layer (eg SiN _x layer) 16 from the side closer to the OLED 3. . As shown in FIG. 11(b), the first inorganic barrier layer 12 is in contact with the upper and inclined side surfaces of the organic planarizing layer 2Pb and the upper surface of the inorganic protective layer 2Pa. That is, the OLED display device 100D has a structure similar to that of the OLED display device 100A shown in FIG. 3B at its end portions, and has excellent moisture resistance reliability.

Next, with reference to FIGS. 13 and 14, an OLED display device 100E and a method of manufacturing the same according to still another embodiment of the present invention will be described. FIGS. 13A and 13B are schematic cross-sectional views of an OLED display device 100E. 14A to 14C are schematic cross-sectional views for explaining the manufacturing method of the OLED display device 100E.

The OLED display device 100E is characterized in that the interlayer insulating layer formed between the drive circuit layer 2 and the OLED layer 3 has the second inorganic protective layer 2Pa2 formed on the organic planarizing layer 2Pb. , is different from the OLED display device 100D. The first inorganic protective layer 2Pa1 of the OLED display device 100E is the same as the inorganic protective layer 2Pa of the OLED display device 100D. In FIGS. 13 and 14, members common to the OLED display device 100D are denoted by common reference numerals, and description thereof may be omitted.

As shown in FIG. 13A, in the OLED display device 100E, the organic planarization layer 2Pb has a surface 2Pb_Sb with a large surface roughness (Ra>50 nm), and the second inorganic protective layer 2Pa2 has a smooth surface. surface 2Pa2_Sb. The surface 2Pa2_Sb of the second inorganic protective layer 2Pa2 and the surfaces C_Sb of the contact portions C1 and C2 are flush with each other, and have an arithmetic mean roughness Ra of 50 nm or less. Therefore, the OLED display device 100E has improved luminous efficiency, like the OLED display device 100D. Furthermore, the degree of freedom in designing the arrangement of the contact portions is increased, and the area ratio of pixels can be improved.

Further, as shown in FIG. 13B, the first inorganic barrier layer 12 is formed on the upper surface and inclined side surfaces of the second inorganic protective layer 2Pa2, the inclined side surfaces of the organic planarization layer 2Pb, and the upper surface of the first inorganic protective layer 2Pa1. in contact. That is, the OLED display device 100E has a structure similar to that of the OLED display device 100A shown in FIG. 3B at its end portions, and has excellent moisture resistance reliability.

A method of manufacturing the OLED display device 100E will be described with reference to FIGS. Here, differences from the OLED display device 100D are mainly described.

As shown in FIG. 14A, a second inorganic protective film 2Pa2 is formed on the organic planarizing layer 2Pb. As with the first inorganic protective film 2Pa1, the second inorganic protective film 2Pa2 is also selectively formed in a desired region using a mask. Since the second inorganic protective film 2Pa2 is formed on the surface 2Pb_Sa of the organic planarizing film 2Pb, it has a surface roughness (Ra>50 nm) that is approximately the same as the surface 2Pb_Sa of the organic planarizing film 2Pb. For example, when forming the second inorganic protective film 2Pa2 with a single layer of SiN _x film by plasma CVD, the SiN _x film having a thickness of 150 nm or more is formed at a deposition rate not exceeding 10 nm/s, for example. As a result, the second inorganic protective film 2Pa2 reflecting the surface roughness of the base is obtained.

Next, as shown in FIG. 14B, the first inorganic protective film 2Pa1, the organic planarizing film 2Pb, and the second inorganic protective film 2Pa2 formed on desired regions of the element substrate 20 are collectively patterned. , contact holes CH1 and CH2 are formed. This patterning can be performed, for example, by dry etching using a mixed gas of O ₂ and CF ₄ . In addition, as shown in FIG. 13(b), in order to form a portion where the first inorganic protective layer 2Pa1 and the first inorganic barrier layer (not shown) constituting the TFE structure 10E are in direct contact, the first inorganic protective layer The portion where only layer 2Pa1 is left can be formed, for example, by using a multi-tone mask.

Next, as shown in FIG. 14(c), the surface 2Pa2_Sa of the second inorganic protective film 2Pa2 and the surface C_Sa of the contact film C are subjected to chemical mechanical polishing to obtain a smooth surface of the second inorganic protective layer 2Pa2 and the surface C_Sa of the contact film C. Contact portions C1 and C2 are obtained. The surface 2Pa2_Sb of the second inorganic protective layer 2Pa2 and the surface C_Sb of the contact layer C are flush with each other and have an arithmetic mean roughness Ra of 50 nm or less. Chemical mechanical polishing can be performed in the same manner as described above.

Next, a film forming apparatus 200 used for forming an organic barrier layer and a film forming method using the same will be described with reference to FIGS. 15(a) and (b) are diagrams schematically showing the configuration of the film forming apparatus 200. FIG. 15(a) shows a chamber containing photocurable resin vapor or atomized photocurable resin. 15B shows the state of the film forming apparatus 200 in the step of condensing the photocurable resin on the first inorganic barrier layer, and FIG. The state of the film forming apparatus 200 in the step of curing the curable resin is shown.

The film forming apparatus 200 has a chamber 210 and a partition wall 234 that divides the interior of the chamber 210 into two spaces. A stage 212 and a shower plate 220 are arranged in one of the spaces inside the chamber 210 partitioned by the partition wall 234 . An ultraviolet irradiation device 230 is arranged in the other space partitioned by the partition wall 234 . The chamber 210 controls the internal space to a predetermined pressure (degree of vacuum) and temperature. The stage 212 has an upper surface for receiving the element substrate 20 having a plurality of OLEDs 3 on which the first inorganic barrier layer is formed, and the upper surface can be cooled to -20°C, for example.

The shower plate 220 is arranged to form a gap 224 with the partition wall 234 and has a plurality of through holes 222 . The vertical size of the gap 224 can be, for example, 100 mm or more and 1000 mm or less. The acrylic monomer (vapor or mist) supplied to the gap 224 is supplied to the space on the stage 212 side inside the chamber 210 through the plurality of through holes 222 of the shower plate 220 . The acrylic monomer is heated as necessary. Acrylic monomer vapor or mist of acrylic monomer 26 p adheres to or contacts the first inorganic barrier layer of device substrate 20 . Acrylic monomer 26 is supplied from container 202 into chamber 210 at a predetermined flow rate. The container 202 is supplied with the acrylic monomer 26 through a pipe 206 and is supplied with nitrogen gas through a pipe 204 . The flow rate of acrylic monomer to vessel 202 is controlled by mass flow controller 208 . The shower plate 220, the container 202, the pipes 204 and 206, the mass flow controller 208, etc. constitute a raw material supply device.

The ultraviolet irradiation device 230 has an ultraviolet light source and optional optical elements. The ultraviolet light source may be, for example, an ultraviolet lamp (eg, a mercury lamp (including high pressure and ultrahigh pressure), a mercury xenon lamp, or a metal halide lamp). Optical elements are, for example, reflectors, prisms, lenses, and diffraction elements.

When the ultraviolet irradiation device 230 is placed at a predetermined position, it emits light having a predetermined wavelength and intensity toward the upper surface of the stage 212 . The partition wall 234 and the shower plate 220 are preferably made of a material having high ultraviolet transmittance, such as quartz.

Using the film forming apparatus 200, the organic barrier layer 14 can be formed, for example, as follows. Here, an example using an acrylic monomer as the photocurable resin will be described.

In the chamber 210, an acrylic monomer 26p is supplied. The element substrate 20 is cooled to -15° C., for example, on the stage 212 . Acrylic monomer 26p is condensed on first inorganic barrier layer 12 of device substrate 20 . By controlling the conditions at this time, the liquid acrylic monomer can be unevenly distributed only around the protrusions of the first inorganic barrier layer 12 . Alternatively, the conditions are controlled so that the acrymonomer condensed on the first inorganic barrier layer 12 forms a liquid film.

By adjusting the viscosity and/or surface tension of the liquid photocurable resin, it is possible to control the thickness of the liquid film and the shape (concave shape) of the portion of the first inorganic barrier layer 12 in contact with the convex portion. For example, viscosity and surface tension are temperature dependent and can be controlled by adjusting the temperature of the device substrate. For example, the size of the solid portion existing on the flat portion can be controlled by the shape (concave shape) of the portion of the liquid film in contact with the convex portion of the first inorganic barrier layer 12 and the conditions of the ashing treatment to be performed later.

Subsequently, the acrylic monomer on the first inorganic barrier layer 12 is cured, typically by irradiating the entire upper surface of the element substrate 20 with ultraviolet rays 232 using an ultraviolet irradiation device 230 . As an ultraviolet light source, for example, a ^high pressure mercury lamp having a main peak at 365 nm is used.

The organic barrier layer 14 made of acrylic resin is thus formed. The tact time of the process of forming the organic barrier layer 14 is, for example, less than about 30 seconds, which is very high in mass productivity.

The organic barrier layer 14 may be formed only around the projections through an ashing process after the liquid film-like photocurable resin is cured. The ashing process may also be performed when the organic barrier layer 14 is formed by curing the unevenly distributed photocurable resin. The ashing treatment can improve the adhesiveness between the organic barrier layer 14 and the second inorganic barrier layer 16 . That is, the ashing treatment may be used not only to remove the excess portion of the organic barrier layer once formed, but also to modify (make hydrophilic) the surface of the organic barrier layer 14 .

Ashing can be performed using a known plasma ashing device, photoexcited ashing device, or UV ozone ashing device. For example, plasma ashing using at least one gas selected from N ₂ O, O ₂ and O ₃ , or a combination thereof with ultraviolet irradiation can be performed. When SiN _x films are formed as the first inorganic barrier layer 12 and the second inorganic barrier layer 16 by the CVD method, N ₂ O is used as a raw material gas, so using N ₂ O for ashing can simplify the equipment. You get the advantage of

When ashing is performed, the surface of the organic barrier layer 14 is oxidized and modified to be hydrophilic. In addition, the surface of the organic barrier layer 14 is scraped almost uniformly, and extremely fine unevenness is formed, increasing the surface area. The effect of increasing the surface area by ashing is greater for the surface of the organic barrier layer 14 than for the first inorganic barrier layer 12, which is an inorganic material. Therefore, since the surface of the organic barrier layer 14 is modified to be hydrophilic and the surface area is increased, the adhesion to the second inorganic barrier layer 16 is improved.

Thereafter, the substrate is transferred to a CVD chamber for forming the second inorganic barrier layer 16, and the second inorganic barrier layer 16 is formed under the same conditions as the first inorganic barrier layer 12, for example. Since the second inorganic barrier layer 16 is formed in the region where the first inorganic barrier layer 12 is formed, the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are formed in the non-solid portion of the organic barrier layer 14 . An inorganic barrier layer junction is formed that directly contacts the . Therefore, as described above, water vapor in the atmosphere is suppressed or prevented from reaching the active region through the organic barrier layer.

The first inorganic barrier layer 12 and the second inorganic barrier layer 16 are formed, for example, as follows. By a plasma CVD method using SiH ₄ and N ₂ O gas, for example, a film having a thickness of 400 nm is formed at a film forming rate of 400 nm/min while the temperature of the substrate (OLED 3) to be film-formed is controlled to 80° C. or less. An inorganic barrier layer can be formed. The inorganic barrier layer thus obtained has a refractive index of 1.84 and a transmittance of visible light of 400 nm of 90% (thickness of 400 nm). Also, the absolute value of the film stress is 50 MPa.

As the inorganic barrier layer, in addition to the _SiNx layer, a _SiO2 layer, a _SiOxNy ( _x >y) layer, a SiNxOy ( _x > _y ) layer, an _Al2O3 layer _, or the like can also be used. . Photocurable resins include, for example, vinyl group-containing monomers. Among these, acrylic monomers are preferably used. A photopolymerization initiator may be mixed with the acrylic monomer, if necessary. Various known acrymonomers can be used. A plurality of acrylic monomers may be mixed. For example, a bifunctional monomer and a trifunctional or higher polyfunctional monomer may be mixed. Moreover, you may mix an oligomer. The viscosity of the photocurable resin at room temperature (for example, 25° C.) before curing preferably does not exceed 10 Pa·s, particularly preferably from 1 to 100 mPa·s. If the viscosity is high, it may be difficult to form a thin liquid film with a thickness of 500 nm or less.

Although embodiments of an OLED display device having a flexible substrate and a method of manufacturing the same have been described above, the embodiments of the present invention are not limited to the exemplified ones. It can be widely applied to an organic EL device (for example, an organic EL lighting device) having an organic EL element and a thin-film sealing structure formed on the organic EL element.

Embodiments of the present invention are used in organic EL devices and methods of manufacturing the same. Embodiments of the present invention are particularly suitable for flexible organic EL display devices and manufacturing methods thereof.

1: flexible substrate 2: backplane (circuit)
2 Pa: inorganic protective layer (first inorganic protective layer), inorganic protective film (first inorganic protective film)
2Pa1: first inorganic protective layer, first inorganic protective film 2Pa2: second inorganic protective layer, second inorganic protective film 2Pb: organic planarizing layer, organic planarizing film 3: organic EL element 4: polarizing plate 10: thin film sealing Stopping structure (TFE structure)
12: first inorganic barrier layer (SiN _x layer)
14: Organic barrier layer (acrylic resin layer)
16: Second inorganic barrier layer (SiN _x layer)
20: Element substrate 100, 100A, 100D, 100E: Organic EL display device 200: Film deposition device

Claims (7)

A method for manufacturing an organic EL device,
The organic EL device is
a substrate;
a plurality of TFTs formed on the substrate, a plurality of gate bus lines and a plurality of source bus lines each connected to one of the plurality of TFTs, a plurality of terminals, the plurality of terminals and the plurality of a driving circuit layer having a plurality of lead-out wirings connecting to either one of the gate bus lines or the plurality of source bus lines;
an interlayer insulating layer formed on the drive circuit layer;
an organic EL element layer formed on the interlayer insulating layer and having a plurality of organic EL elements each connected to one of the plurality of TFTs;
a thin film encapsulation structure formed to cover the organic EL element layer;
the interlayer insulating layer has a contact hole,
a contact portion connecting the drive circuit layer and the organic EL element layer is formed in the contact hole,
The interlayer insulating layer has a first inorganic protective layer exposing at least the plurality of terminals, and an organic planarizing layer formed on the first inorganic protective layer, wherein the surface of the organic planarizing layer is processed. Average roughness Ra is 50 nm or less,
The thin-film sealing structure has a first inorganic barrier layer, an organic barrier layer in contact with the upper surface of the first inorganic barrier layer, and a second inorganic barrier layer in contact with the upper surface of the organic barrier layer, and the organic barrier a layer formed in a region surrounded by an inorganic barrier layer junction where the first inorganic barrier layer and the second inorganic barrier layer are in direct contact;
When viewed from the normal direction of the substrate, the organic planarizing layer is formed within the region where the first inorganic protective layer is formed, and the organic planarizing layer is formed within the region where the organic planarizing layer is formed. A plurality of organic EL elements are arranged, the outer edge of the thin-film sealing structure crosses the plurality of lead wirings, and is between the outer edge of the organic planarization layer and the outer edge of the first inorganic protective layer. exists in
A section of the first inorganic barrier layer parallel to the line width direction of the plurality of lead wires in a portion where the first inorganic protective layer and the first inorganic barrier layer are in direct contact on the plurality of lead wires. The taper angle of the side surface in the shape of is less than 90°,
forming the drive circuit layer on the substrate;
forming an interlayer insulating film having a contact hole on the drive circuit layer;
forming a conductive contact film covering the interlayer insulating film;
obtaining the interlayer insulating layer having the organic planarization layer and the contact portion by subjecting the surface of the contact film and the surface of the interlayer insulating film to chemical mechanical polishing;
forming an organic layer included in the organic EL element on the organic planarizing layer;
forming a positive photoresist film covering the organic planarization layer before forming the organic layer; and exposing and developing the photoresist film after moving or storing the substrate . , and removing the photoresist film. the organic EL device having a plurality of pixels, each pixel including one of the plurality of organic EL elements;
2. The manufacturing method according to claim 1, wherein said contact portion is formed inside each of said plurality of pixels. The plurality of organic EL elements have a lower electrode, an organic layer, and an upper electrode facing the lower electrode via the organic layer,
3. The manufacturing method according to claim 1, wherein said contact portion is made of a material different from that of said lower electrode. 4. The manufacturing method according to any one of claims 1 to 3, wherein the taper angle of the side surface of the first inorganic barrier layer is less than 70[deg.]. 5. The manufacturing method according to claim 1, wherein said organic planarization layer is made of polyimide. 6. The step of forming the contact film according to any one of claims 1 to 5, wherein the step of forming the contact film includes the step of forming a titanium film by a sputtering method and the step of forming a copper film on the titanium film by a plating method. manufacturing method. 7. The manufacturing method according to claim 1, further comprising a step of removing moisture contained in said organic planarizing layer after said step of removing said photoresist film and before forming said organic layer. .

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