Indication device

Abstract

To provide a high-definition display device. To provide a display device with a high aperture ratio. [Solution] The display device includes a first pixel electrode, a second pixel electrode, a first insulating layer, a second insulating layer, a first EL layer, a second EL layer, and a common electrode. The first insulating layer covers the ends of the first and second pixel electrodes. The second insulating layer is provided on the first and second pixel electrodes and the first insulating layer, and covers the ends of the first insulating layer. The first EL layer is provided on the first pixel electrode, and the second EL layer is provided on the second pixel electrode. The ends of the first EL layer and the ends of the second EL layer face each other and overlap with the first insulating layer. The common electrode has a portion that overlaps with the first EL layer and a portion that overlaps with the second EL layer. The first insulating layer contains an organic resin, and the second insulating layer contains an inorganic insulating material.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device. Another aspect of the present invention relates to a method for manufacturing a display device.

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. Examples of technical fields of one aspect of the present invention disclosed herein include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, methods for driving them, or methods for manufacturing them. A semiconductor device refers to any device that can function by utilizing semiconductor properties. [Background technology]

[0003] In recent years, there has been a growing demand for higher resolution display panels. Devices requiring high-resolution display panels include smartphones, tablet devices, and notebook computers. Furthermore, stationary display devices such as television sets and monitors are also demanding higher resolutions. Devices requiring the highest level of resolution include those used for virtual reality (VR) and augmented reality (AR).

[0004] Furthermore, typical examples of display devices applicable to display panels include liquid crystal displays, organic EL (Electro Luminescence) elements, light-emitting devices equipped with light-emitting elements such as LEDs, and electronic paper that displays information using electrophoretic methods.

[0005] For example, an example of a display device for VR using an organic EL element is described in Patent Document 1. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2018 / 087625 [Overview of the project] [Problems that the invention aims to solve]

[0007] One aspect of the present invention aims to provide a high-definition display device. Another aspect of the present invention aims to provide a display device with a high aperture ratio. Another aspect of the present invention aims to provide a display device that combines high display quality and high resolution. Another aspect of the present invention aims to provide a display device with high contrast. Another aspect of the present invention aims to provide a highly reliable display device.

[0008] One aspect of the present invention aims to provide a display device having a novel configuration, or a method for manufacturing a display device. Another aspect of the present invention aims to provide a method for manufacturing the above-mentioned display device with a high yield. Another aspect of the present invention aims to mitigate at least one of the problems of the prior art.

[0009] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems can be identified from the description in the specification, drawings, claims, etc. [Means for solving the problem]

[0010] One aspect of the present invention is a display device having a first pixel electrode, a second pixel electrode, a first insulating layer, a second insulating layer, a first EL layer, a second EL layer, and a common electrode. The first pixel electrode and the second pixel electrode are provided side by side. The first insulating layer covers the end portions of the first pixel electrode and the second pixel electrode. Among the end portions of the first insulating layer, a part overlaps the upper surface of the first pixel electrode, and another part overlaps the upper surface of the second pixel electrode. The second insulating layer is provided on the first pixel electrode, the second pixel electrode, and the first insulating layer, and covers the end portion of the first insulating layer. Among the end portions of the second insulating layer, a part overlaps the upper surface of the first pixel electrode, and another part overlaps the upper surface of the second pixel electrode. The first EL layer is provided on the first pixel electrode, and the second EL layer is provided on the second pixel electrode. The end portion of the first EL layer and the end portion of the second EL layer face each other and overlap the first insulating layer. The common electrode has a portion overlapping the first EL layer and a portion overlapping the second EL layer. The first insulating layer contains an organic resin, and the second insulating layer contains an inorganic insulating material.

[0011] Also, in the above, it is preferable that the first insulating layer has a curved surface between the upper surface and the end portion. Further, it is preferable that the second insulating layer has a portion where the angle formed by the side surface and the bottom surface is 20 degrees or more and less than 90 degrees.

[0012] Also, in any of the above, it is preferable that the first insulating layer contains an acrylic resin, a polyimide resin, an epoxy resin, a polyamide resin, a polyimide amide resin, a siloxane resin, a benzocyclobutene-based resin, a phenol resin, or a precursor of these resins.

[0013] Also, in any of the above, it is preferable that the second insulating layer contains silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, hafnium oxide, indium gallium oxide, or indium gallium zinc oxide.

[0014] Furthermore, in either of the above, the second insulating layer may have a recess in a region that does not overlap with either the first EL layer or the second EL layer. Alternatively, the second insulating layer may be divided in a region that does not overlap with either the first EL layer or the second EL layer.

[0015] Furthermore, in any of the above, it is preferable that the second insulating layer comprises a first insulating film and a second insulating film on the first insulating film. In this case, it is preferable that the first angle formed by the side surface and bottom surface of the first insulating film and the second angle formed by the side surface and bottom surface of the second insulating film are different.

[0016] Furthermore, in the above, it is preferable that the first insulating film is thinner than the second insulating film and the first angle is larger than the second angle. Alternatively, it is preferable that the second insulating film is thinner than the first insulating film and the second angle is larger than the first angle.

[0017] Furthermore, in either of the above, it is preferable that the first insulating film includes a silicon nitride film and the second insulating film includes a silicon oxide film.

[0018] Furthermore, one aspect of the present invention is a method for manufacturing a display device, comprising: forming a first pixel electrode and a second pixel electrode; forming a photosensitive resin film covering the first and second pixel electrodes; exposing the resin film using a first photomask and developing it to form a first insulating layer covering the ends of the first and second pixel electrodes; forming an inorganic insulating film covering the first pixel electrode, the second pixel electrode and the first insulating layer; forming a resist film on the inorganic insulating film; exposing the resist film using a first photomask and developing it to form a resist mask; and etching the inorganic insulating film not covered by the resist mask to form a second insulating layer covering the upper surface of the first pixel electrode, the upper surface of the second pixel electrode and the upper surface of the first insulating layer.

[0019] Furthermore, in the above, it is preferable to form a first EL layer on the first pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the first and second EL layers after the formation of the second insulating layer. In this case, it is preferable that the first EL layer and the second EL layer are processed into island-like or strip-like shapes by photolithography. [Effects of the Invention]

[0020] According to one aspect of the present invention, a high-definition display device can be provided. Alternatively, a display device that combines high display quality and high resolution can be provided. Alternatively, a display device with high contrast can be provided. Alternatively, a highly reliable display device can be provided.

[0021] According to one aspect of the present invention, a display device having a novel configuration, or a method for manufacturing a display device, can be provided. Alternatively, a method for manufacturing the above-described display device with high yield can be provided. Alternatively, one aspect of the present invention can mitigate at least one of the problems of the prior art.

[0022] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawing]

[0023] [Figure 1] Figures 1A to 1D show examples of the configuration of a display device. [Figure 2] Figures 2A and 2B show examples of display device configurations. [Figure 3] Figures 3A to 3C show examples of display device configurations. [Figure 4] Figures 4A to 4C show examples of the configuration of a display device. [Figure 5] Figures 5A to 5G show examples of methods for manufacturing a display device. [Figure 6]Figures 6A to 6F show examples of methods for manufacturing a display device. [Figure 7] Figures 7A to 7E show examples of methods for manufacturing a display device. [Figure 8] Figures 8A to 8C show examples of methods for manufacturing a display device. [Figure 9] Figures 9A to 9C show examples of methods for manufacturing a display device. [Figure 10] Figures 10A to 10C show examples of the configuration of a display device. [Figure 11] Figures 11A to 11C show examples of display device configurations. [Figure 12] Figures 12A to 12C show examples of display device configurations. [Figure 13] Figure 13 is a perspective view showing an example of a display device. [Figure 14] Figures 14A and 14B are cross-sectional views showing an example of a display device. [Figure 15] Figure 15A is a cross-sectional view showing an example of a display device. Figure 15B is a cross-sectional view showing an example of a transistor. [Figure 16] Figures 16A to 16D show examples of the configuration of a light-emitting element. [Figure 17] Figures 17A to 17J show examples of display device configurations. [Figure 18] Figures 18A and 18B show examples of electronic devices. [Figure 19] Figures 19A to 19D show examples of electronic devices. [Figure 20] Figures 20A to 20F show examples of electronic devices. [Figure 21] Figures 21A to 21F show examples of electronic devices. [Figure 22] Figure 22A is a cross-sectional view. Figure 22B is a schematic diagram of the cross-section. [Modes for carrying out the invention]

[0024] The embodiments will be described below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the embodiments can be implemented in many different ways, and their form and details can be modified in various ways without departing from the spirit and scope thereof. Accordingly, the present invention shall not be construed as being limited to the contents of the following embodiments.

[0025] In the configuration of the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the hatch patterns are the same, and reference numerals may not be assigned.

[0026] In the figures described herein, the size of each component, the thickness of the layers, or the area may be exaggerated for clarity. Therefore, the scale is not necessarily limited to those figures.

[0027] Furthermore, ordinal numbers such as "the first," "the second," etc., used in this specification are added to avoid confusion of constituent elements and do not imply any numerical limitation.

[0028] Furthermore, in this specification, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" or "insulating layer" may be interchangeable with the terms "conductive film" or "insulating film."

[0029] In this specification, the term "EL layer" refers to a layer (also called a light-emitting layer) provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance, or a laminate including a light-emitting layer.

[0030] In this specification, a display panel, which is one form of a display device, has the function of displaying (outputting) images or the like on its display surface. Therefore, a display panel is one form of an output device.

[0031] Furthermore, in this specification, a display panel on which a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached, or on which an IC is mounted on the board using a COG (Chip On Glass) method, may be referred to as a display panel module, display module, or simply a display panel.

[0032] (Embodiment 1) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention, and an example of a method for manufacturing the display device.

[0033] One aspect of the present invention is a display device having light-emitting elements (also called light-emitting devices). The display device has at least two light-emitting elements with different emission colors. Each light-emitting element has a pair of electrodes and an EL layer between them. The light-emitting elements are preferably organic EL elements (organic electroluminescent elements). Two or more light-emitting elements that emit different colors each have an EL layer containing a different material. For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0034] Here, when differentiating between light-emitting elements of different colors by creating part or all of the EL layer, it is known that this is done by deposition using a shadow mask such as a metal mask. However, with this method, deviations from the design occur in the shape and position of the island-like organic film due to various influences such as the precision of the metal mask, the misalignment between the metal mask and the substrate, the deflection of the metal mask, and the spreading of the contour of the deposited film due to vapor scattering, making it difficult to increase the resolution and aperture ratio of the display device. For this reason, measures have been taken to artificially increase the resolution (also called pixel density) by applying special pixel arrangement methods such as pentile arrangements.

[0035] One aspect of the present invention involves processing the EL layer into a fine pattern without using a shadow mask such as a metal mask. This makes it possible to realize a display device with high resolution and a large aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be differentiated, it is possible to realize a display device with extremely vivid colors, high contrast, and high display quality.

[0036] Here, for simplicity, we will explain the case where the EL layers of two-color light-emitting elements are created separately. First, a first EL film and a first sacrificial film are laminated and formed covering the two pixel electrodes. Next, a resist mask is formed on the first sacrificial film at a position overlapping with one of the pixel electrodes (the first pixel electrode). Then, a portion of the first sacrificial film and a portion of the first EL film that do not overlap with the resist mask are etched. At this point, the etching is stopped when the other pixel electrode (the second pixel electrode) is exposed. As a result, a portion of the first EL film (also called the first EL layer), processed into a strip or island shape, and a portion of the sacrificial film (also called the first sacrificial layer) are formed on the first pixel electrode.

[0037] Next, the second EL film and the second sacrificial film are laminated together. Then, a resist mask is formed in a position that overlaps with the second pixel electrode. Subsequently, a portion of the second sacrificial film and a portion of the second EL film that do not overlap with the resist mask are etched in the same manner as above. As a result, the first EL layer and the first sacrificial layer are provided on the first pixel electrode, and the second EL layer and the second sacrificial layer are provided on the second pixel electrode. In this way, the first EL layer and the second EL layer can be created separately. Finally, the first and second sacrificial layers are removed, exposing the first and second EL layers, and then a common electrode is formed to create two different colored light-emitting elements.

[0038] Furthermore, by repeating the above process, it is possible to create EL layers of three or more light-emitting elements, thereby realizing a display device having three or four or more light-emitting elements.

[0039] Here, a first insulating layer is provided to cover the respective ends of the first and second pixel electrodes. By providing the first insulating layer, the step coverage of the first and second EL layers can be improved. In addition, it is possible to prevent an increase in leakage current due to the first or second EL layer becoming thinner at the ends of the first or second pixel electrode, and to prevent electrical short circuits between the first or second pixel electrode and the common electrode.

[0040] Furthermore, a second insulating layer is provided, covering the first insulating layer. In this case, it is preferable that the second insulating layer be formed to have a larger pattern than the first insulating layer. Specifically, it is preferable that they be formed so that, in a plan view, the first insulating layer is located inside the contour of the second insulating layer. In this case, the first insulating layer is covered by the second insulating layer. In addition, the second insulating layer has portions at its edges that overlap with the first and second pixel electrodes, respectively.

[0041] For the second insulating layer, it is preferable to use an insulating film containing an inorganic insulating material. For the etching process of the first EL layer and the second EL layer, it is more preferable to use an insulating film with etching resistance. Furthermore, for the removal process of the first sacrificial layer and the second sacrificial layer, it is preferable to use an insulating film with etching resistance.

[0042] On the other hand, it is preferable to use an insulating film containing an organic insulating material such as an organic resin for the first insulating layer. In this case, it is preferable that the first insulating layer has a curved shape with a gentle slope from the edge to the top surface. This makes it possible to improve the step coverage of the first EL layer and the second EL layer.

[0043] By providing a second insulating layer on top of the first insulating layer, it is possible to prevent part or all of the first insulating layer from being etched when the first EL layer or the second EL layer is etched. Furthermore, when these are etched, a recess is formed in the first insulating layer, which increases the height difference between the upper surfaces of the first EL layer and the second EL layer and the upper surface of the first insulating layer, thus preventing the common electrode from being broken when it is formed.

[0044] In this way, by covering the ends of the first and second pixel electrodes with a laminated film comprising a first insulating layer containing an organic resin and a second insulating layer containing an inorganic insulating material, a highly reliable display device can be realized.

[0045] Here, it is preferable that the first insulating layer and the second insulating layer are processed using the same photomask (exposure mask). For example, the first insulating layer is formed by depositing a photosensitive organic resin film, exposing it using a photomask, and then developing it. At this time, by controlling the exposure conditions, the first insulating layer is formed so that the pattern width is narrower than the pattern width of the photomask. The second insulating layer can be formed by forming a resist mask patterned using the above photomask on an insulating film, and etching the parts not covered by the resist mask. At this time, by controlling the exposure conditions of the resist mask, the resist mask is formed so that the pattern width is wider than that of the first insulating layer. This makes it possible to create insulating layers with different pattern widths using the same photomask.

[0046] In this configuration, an electrode (also called a first electrode or connecting electrode) can be provided on the same plane as the pixel electrode to supply potential to the common electrode, and the connecting electrode and the common electrode can be electrically connected. The connecting electrode is positioned outside the display section where the pixels are provided. Preferably, a first insulating layer and a second insulating layer are provided on the connecting electrode, covering its end.

[0047] Here, in order to prevent the upper surface of the connecting electrode from being exposed to etching during the etching of the first EL film, it is preferable to provide a first sacrificial layer on the connecting electrode as well. Similarly, when etching the second EL film, it is preferable to provide a second sacrificial layer on the connecting electrode. The first and second sacrificial layers provided on the connecting electrode can be removed by etching simultaneously with the first sacrificial layer on the first EL layer and the second sacrificial layer on the second EL layer.

[0048] While it is difficult to reduce the spacing between different colored EL layers to less than 10 μm using, for example, a metal mask formation method, the above method allows for narrowing the spacing to 3 μm or less, 2 μm or less, or even 1 μm or less. For example, by using an exposure apparatus for LSIs, the spacing can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, and even 50 nm or less. This significantly reduces the area of ​​the non-emitting region that may exist between two light-emitting elements, making it possible to approach an aperture ratio of 100%. For example, an aperture ratio of 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, can be achieved, and even less than 100%.

[0049] Furthermore, the pattern of the EL layer itself can be made extremely small compared to when a metal mask is used. Also, for example, when a metal mask is used to create different EL layers, variations in thickness occur between the center and edges of the pattern, so the effective area that can be used as an emitting region is small relative to the total area of ​​the pattern. On the other hand, with the above manufacturing method, the pattern is formed by processing a film deposited to a uniform thickness, so the thickness can be made uniform within the pattern, and even if the pattern is fine, almost the entire area can be used as an emitting region. Therefore, with the above manufacturing method, it is possible to achieve both high resolution and a high aperture ratio.

[0050] Furthermore, the first and second insulating layers, provided between two adjacent pixel electrodes, are positioned to cover the edges of the pixel electrodes. Since the area on the pixel electrode covered by the second insulating layer does not function as a light-emitting region of the light-emitting element, the smaller the width of the overlapping region between the second insulating layer and the pixel electrode, the higher the effective light-emitting area ratio, i.e., the aperture ratio, of the display device.

[0051] Furthermore, the edges of the EL layer are located on the first insulating layer and the second insulating layer. In this case, the sides of the two EL layers are arranged facing each other on the second insulating layer. The narrower the distance between the two EL layers, the smaller the width of the insulating layer can be, and thus the aperture ratio of the display device can be increased. For example, the distance between the sides of two opposing EL layers is 5 μm or less, preferably 4 μm or less, more preferably 3 μm or less, even more preferably 2 μm or less, and even more preferably 1 μm or less, and can be 10 nm or more, 50 nm, or 100 nm or more.

[0052] Thus, one aspect of the present invention makes it possible to realize a display device that integrates fine light-emitting elements. For example, since there is no need to apply a special pixel arrangement method such as the pentile method to artificially increase the resolution, a display device can be realized with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, even 3000 ppi or more, and even 5000 ppi or more, using a so-called stripe arrangement in which R, G, and B are each arranged in one direction. Furthermore, a display device can be realized with an effective light-emitting area ratio (aperture ratio) of 50% or more, even 60% or more, even 70% or more, and less than 100%.

[0053] Furthermore, one aspect of the present invention makes it possible to accurately fabricate minute light-emitting elements, thereby enabling the realization of complex pixel arrangement methods. For example, various arrangement methods such as S-strip arrangements, Bayer arrangements, and delta arrangements can be applied in addition to stripe arrangements.

[0054] In this specification, the effective light-emitting area ratio refers to the ratio of the area of ​​the region that can be considered as a light-emitting region within a single pixel to the area of ​​a single pixel calculated from the repeating pitch of the pixels of the display device.

[0055] In the following section, a more specific configuration example and manufacturing method example of a display device according to one aspect of the present invention will be described with reference to the drawings.

[0056] [Configuration Example 1] Figure 1A shows a schematic top view of a display device 100 according to one embodiment of the present invention. The display device 100 has multiple red-emitting light-emitting elements 110R, green-emitting light-emitting elements 110G, and blue-emitting light-emitting elements 110B. In Figure 1A, the labels R, G, and B are added within the light-emitting area of ​​each light-emitting element to simplify the distinction between them.

[0057] The light-emitting elements 110R, 110G, and 110B are each arranged in a matrix. Figure 1A shows a so-called stripe arrangement, in which light-emitting elements of the same color are arranged in one direction. However, the arrangement method of the light-emitting elements is not limited to this, and other arrangement methods such as S-stripe arrangement, delta arrangement, Bayer arrangement, zigzag arrangement may be applied, or a pentile arrangement may be used.

[0058] The light-emitting elements 110R, 110G, and 110B are arranged in the X direction. In addition, light-emitting elements of the same color are arranged in the Y direction, which intersects with the X direction.

[0059] It is preferable to use EL elements such as OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) as the light-emitting elements 110R, 110G, and 110B. Examples of light-emitting materials for EL elements include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. Not only organic compounds but also inorganic compounds (such as quantum dot materials) can be used as light-emitting materials for EL elements.

[0060] Figure 1B is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A, and Figure 1C is a schematic cross-sectional view corresponding to the dashed line B1-B2.

[0061] Figure 1B shows cross-sections of light-emitting elements 110R, 110G, and 110B. Light-emitting element 110R has a pixel electrode 111R, an EL layer 112R, an EL layer 114, and a common electrode 113. Light-emitting element 110G has a pixel electrode 111G, an EL layer 112G, an EL layer 114, and a common electrode 113. Light-emitting element 110B has a pixel electrode 111B, an EL layer 112B, an EL layer 114, and a common electrode 113. The EL layer 114 and the common electrode 113 are provided in common to light-emitting elements 110R, 110G, and 110B. The EL layer 114 can also be called a common layer.

[0062] The EL layer 112R of the light-emitting element 110R has a luminescent organic compound that emits light with intensity in at least the red wavelength range. The EL layer 112G of the light-emitting element 110G has a luminescent organic compound that emits light with intensity in at least the green wavelength range. The EL layer 112B of the light-emitting element 110B has a luminescent organic compound that emits light with intensity in at least the blue wavelength range.

[0063] Each of the EL layers 112R, 112G, and 112B may have, in addition to a layer containing a light-emitting organic compound (light-emitting layer), one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. The EL layer 114 may have a configuration without a light-emitting layer. For example, the EL layer 114 may have one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer.

[0064] In this case, it is preferable that the uppermost layer in the stacked structure of EL layer 112R, EL layer 112G, and EL layer 112B, i.e., the layer in contact with EL layer 114, be a layer other than the light-emitting layer. For example, it is preferable to cover the light-emitting layer with an electron injection layer, electron transport layer, hole injection layer, hole transport layer, or other layer, and to have this layer in contact with EL layer 114. In this way, the reliability of the light-emitting device can be improved by protecting the upper surface of the light-emitting layer with another layer when manufacturing each light-emitting device.

[0065] Pixel electrodes 111R, 111G, and 111B are provided for each light-emitting element. The common electrode 113 and EL layer 114 are provided as a continuous layer common to each light-emitting element. A conductive film that is transparent to visible light is used on either each pixel electrode or the common electrode 113, while a conductive film that is reflective is used on the other. By making each pixel electrode transparent and the common electrode 113 reflective, a bottom-emission type display device can be created. Conversely, by making each pixel electrode reflective and the common electrode 113 transparent, a top-emission type display device can be created. Furthermore, by making both each pixel electrode and the common electrode 113 transparent, a dual-emission type display device can be created.

[0066] An insulating layer 131 is provided covering the ends of the pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B. The insulating layer 131 is preferably tapered. In this specification, an object is said to be tapered in shape if the angle between the surface and the surface to be formed (also called the taper angle) in the region near its end is greater than 0 degrees and less than 90 degrees, and the cross-sectional shape has a thickness that increases continuously from the end.

[0067] Furthermore, by using an organic resin for the insulating layer 131, its surface can be made into a gently curved surface. This improves the coverage of the film formed on the insulating layer 131.

[0068] Examples of materials that can be used for the insulating layer 131 include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0069] An insulating layer 132 is provided on the insulating layer 131. The insulating layer 132 overlaps with the ends of the pixel electrodes 111R, 111G, and 111B via the insulating layer 131. The insulating layer 132 is also provided so as to cover the ends of the insulating layer 131. Furthermore, the insulating layer 132 has portions that are in contact with the upper surfaces of the respective pixel electrodes 111R, 111G, and 111B.

[0070] The insulating layer 132 is preferably tapered. This improves the step coverage of films formed on the insulating layer 132, such as the EL layer that covers the edges of the insulating layer 132.

[0071] Furthermore, it is preferable that the insulating layer 132 is thinner than the insulating layer 131. By making the insulating layer 132 thinner, the step coverage of the film formed on the insulating layer 132 can be improved.

[0072] As inorganic insulating materials that can be used for the insulating layer 132, for example, oxides or nitrides such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, aluminum oxide, aluminum oxide nitride, or hafnium oxide can be used. Alternatively, yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, and neodymium oxide may also be used.

[0073] Furthermore, a metal oxide film such as indium gallium oxide or indium gallium zinc oxide may be used as the insulating layer 132. Such metal oxide films have semiconductor electrical properties and high resistance, so there is almost no risk of the two pixel electrodes short-circuiting electrically through the insulating layer 132.

[0074] Furthermore, the insulating layer 132 may be laminated with a film containing the inorganic insulating material described above. For example, it can be a laminated structure in which a silicon oxide film or a silicon oxynitride film is laminated on a silicon nitride film, or a laminated structure in which a silicon oxide film or a silicon oxynitride film is laminated on an aluminum oxide film. Since the silicon oxide film and the silicon oxynitride film are particularly resistant to etching, it is preferable to place them on the upper side. Also, since the silicon nitride film and the aluminum oxide film are films that do not easily absorb water, hydrogen, oxygen, etc., placing them on the insulating layer 131 side functions as a barrier layer that prevents gases detached from the insulating layer 131 from diffusing into the light-emitting element.

[0075] Each of the EL layers 112R, 112G, and 112B has a region in contact with the upper surface of the pixel electrode and a region in contact with the surface of the insulating layer 131. The edges of the EL layers 112R, 112G, and 112B are located on the insulating layer 131.

[0076] As shown in Figure 1B, a gap is provided between two EL layers when the light-emitting elements have different emission colors. Furthermore, as shown in Figure 1C, it is preferable that a gap is also provided between two EL layers when the light-emitting elements have the same color. Thus, it is preferable that EL layers 112R, 112G, and 112B are arranged so that they do not touch each other. This effectively prevents current from flowing through two adjacent EL layers and causing unintended light emission. As a result, contrast can be increased, and a display device with high display quality can be realized.

[0077] Furthermore, in the Y direction, the EL layers 112R, 112G, or 112B may be formed in a strip shape so that they are continuous between light-emitting elements of the same color. By forming the EL layers 112R, 112G, or 112B in a strip shape, the space required to separate them is eliminated, and the area of ​​the non-emitting region between light-emitting elements can be reduced, thereby increasing the aperture ratio.

[0078] A protective layer 121 is provided on the common electrode 113, covering the light-emitting elements 110R, 110G, and 110B. The protective layer 121 has the function of preventing impurities such as water from diffusing to each light-emitting element from above.

[0079] The protective layer 121 can be, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of inorganic insulating films include oxide films or nitride films such as silicon oxide film, silicon oxide nitride film, silicon nitride film, silicon nitride film, aluminum oxide film, aluminum oxide nitride film, and hafnium oxide film. Alternatively, semiconductor materials such as indium gallium oxide and indium gallium zinc oxide may be used as the protective layer 121.

[0080] Furthermore, a laminated film of an inorganic insulating film and an organic insulating film can also be used as the protective layer 121. For example, it is preferable to have a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films. It is also preferable that the organic insulating film functions as a planarizing film. This makes the upper surface of the organic insulating film flat, thereby improving the coverage of the inorganic insulating film on top of it and enhancing its barrier properties. In addition, since the upper surface of the protective layer 121 is flat, it is preferable because it reduces the influence of uneven shapes caused by the structure below when a structure (e.g., a color filter, touch sensor electrodes, or lens array) is provided above the protective layer 121.

[0081] Figure 1A also shows a connecting electrode 111C that is electrically connected to the common electrode 113. The connecting electrode 111C is supplied with a potential (e.g., anode potential or cathode potential) to the common electrode 113. The connecting electrode 111C is located outside the display area where the light-emitting elements 110R and the like are arranged. The common electrode 113 is also shown with a dashed line in Figure 1A.

[0082] The connecting electrode 111C can be provided along the outer perimeter of the display area. For example, it may be provided along one side of the outer perimeter of the display area, or it may be provided across two or more sides of the outer perimeter of the display area. That is, if the top surface shape of the display area is rectangular, the top surface shape of the connecting electrode 111C can be a strip, L-shape, U-shape (angle bracket shape), or square, etc.

[0083] Figure 1D is a schematic cross-sectional view corresponding to the dashed line C1-C2 in Figure 1A. Figure 1D shows a connection portion 130 where the connecting electrode 111C and the common electrode 113 are electrically connected. In the connection portion 130, the common electrode 113 is placed in contact with the connecting electrode 111C, and a protective layer 121 is provided covering the common electrode 113. In addition, insulating layers 131 and 132 are provided covering the ends of the connecting electrode 111C.

[0084] Next, preferred configurations of the insulating layer 131, insulating layer 132, and their vicinity will be described in detail. Figure 2A shows an enlarged view of the insulating layer 131, insulating layer 132, and their vicinity between two adjacent light-emitting elements. Figure 2B shows a further enlarged view of the edges of the insulating layer 131, the edges of the insulating layer 132, and their vicinity.

[0085] Here, two arbitrary adjacent light-emitting elements are shown as light-emitting elements 110P and 110Q. Each of the light-emitting elements 110P and 110Q is independently one of light-emitting elements 110R, 110G, or 110B. Similarly, each of the EL layers 112P and 112Q is either EL layer 112R, EL layer 112G, or EL layer 112B, and each of the pixel electrodes 111P and 111Q is either pixel electrode 111R, pixel electrode 111G, or pixel electrode 111B.

[0086] The insulating layer 131 and the insulating layer 132 each have a portion that overlaps with the EL layer 112P, a portion that overlaps with the EL layer 112Q, and a portion that does not overlap with either of these.

[0087] Furthermore, the insulating layer 131 has a portion that overlaps with the pixel electrode 111P, a portion that overlaps with the pixel electrode 111Q, and a portion that does not overlap with either of these. Furthermore, the insulating layer 132 on the insulating layer 131 has a portion that is in contact with the pixel electrode 111P, a portion that overlaps with the pixel electrode 111P via the insulating layer 131, a portion that is in contact with the pixel electrode 111Q, and a portion that overlaps with the pixel electrode 111Q via the insulating layer 131.

[0088] As shown in Figure 2B, the angle between the bottom surface and the side surface near the end of the insulating layer 131 (called the taper angle) is defined as angle θ1, and the angle between the bottom surface and the side surface near the end of the insulating layer 132 is defined as angle θ2. Note that since the surface near the end of the insulating layer 131 has a curved shape, the tangent to the end of the insulating layer 131 is shown as a dashed line.

[0089] It is preferable that the angle θ1 of the insulating layer 131 is smaller than the angle θ2 of the insulating layer 132. By reducing the taper angle of the insulating layer 131, the formation of low-density regions in the insulating layer 132 can be suppressed.

[0090] The angle θ1 of the insulating layer 131 can be greater than 0 degrees and less than 90 degrees, preferably 5 degrees or more and 70 degrees or less, more preferably 10 degrees or more and 60 degrees or less, and even more preferably 15 degrees or more and 50 degrees or less.

[0091] On the other hand, the angle θ2 of the insulating layer 132 can be greater than 0 degrees and less than 90 degrees, preferably 10 degrees or more and less than 90 degrees, more preferably 20 degrees or more and less than 90 degrees, and even more preferably 25 degrees or more and 85 degrees or less.

[0092] Furthermore, if the surface of the insulating layer 131 is curved, the top surface and the side surface may be continuous and indistinguishable. In such cases, the surface of the insulating layer 131 near the edge can be defined as the side surface, where the thickness increases from the edge, and the surface of the portion with a constant thickness can be defined as the top surface.

[0093] Figure 3A shows an example where a portion of the upper surface of the insulating layer 132 is etched, and a recess is formed in a part of the insulating layer 132. The thickness of the insulating layer 132 is thinner in the portion not covered by the EL layer 112P and EL layer 112Q than in the portion covered by them. In Figure 3A, the thickness of the portion of the insulating layer 132 covered by EL layer 112P and the thickness of the portion covered by EL layer 112Q are shown to be equal, but these thicknesses may be different.

[0094] Figure 3B also shows an example where the portion of the insulating layer 132 not covered by the EL layer 112P and EL layer 112Q is erased by etching, and the insulating layer 132 is divided into two parts.

[0095] Figure 3C shows an example in which the end face of the insulating layer 132 has been further recessed by etching in Figure 3B. In Figure 3C, a space 133 is formed surrounded by the EL layer 112P, insulating layer 132, insulating layer 131, and EL layer 114.

[0096] Figures 4A to 4C show cross-sections of the insulating layer 131 and insulating layer 132 near the end on the light-emitting element 110 side. The light-emitting element 110 has a pixel electrode 111, an EL layer 112, an EL layer 114, a common electrode 113, etc. The light-emitting element 110 is either the light-emitting element 110P or the light-emitting element 110Q.

[0097] Figure 4A shows an example in which the pixel electrode 111 has a stacked structure. The pixel electrode 111 has a conductive layer 111a and a conductive layer 111b stacked from the substrate 101 side.

[0098] This example shows a conductive layer 111b covering the edge of the conductive layer 111a. This allows the surface of the conductive layer 111a to be protected by the conductive layer 111b.

[0099] The conductive layer 111a can be a film that is reflective to the light emitted by the EL layer 112. On the other hand, the conductive layer 111b can be a film that is transparent to the said light.

[0100] For example, a metal film or an alloy film can be used as the conductive layer 111a. It is preferable to use a metal film with high reflectivity to visible light, such as aluminum or silver, or an alloy film thereof, for the conductive layer 111a because it can improve the light extraction efficiency of the light-emitting element 110.

[0101] As the conductive layer 111b, a conductive material that is transparent to visible light can be used. For example, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, silicon-containing indium tin oxide, and silicon-containing indium zinc oxide can be used.

[0102] Figures 4B and 4C show an example where the insulating layer 132 has a laminated structure. The insulating layer 132 has a laminated structure in which insulating layer 132a and insulating layer 132b are laminated from the substrate 101 side.

[0103] In Figure 4B, the insulating layer 132b is thicker than the insulating layer 132a. In this case, it is preferable that the taper angle of the insulating layer 132b is smaller than the taper angle of the insulating layer 132a.

[0104] On the other hand, in Figure 4C, the insulating layer 132a is thicker than the insulating layer 132b. In this case, it is preferable that the taper angle of the insulating layer 132a is smaller than the taper angle of the insulating layer 132b.

[0105] Thus, when the insulating layer 132 has a laminated structure, the step coverage of the EL layer 112 can be improved by reducing the taper angle for thicker films.

[0106] Furthermore, the above is not limited to cases where a thinner film has a smaller taper angle than a thicker film. Also, the insulating layer 132 may have a laminated structure of three or more layers.

[0107] [Example of manufacturing method] In the following, an example of a method for manufacturing a display device according to one aspect of the present invention will be described with reference to the drawings. Here, the display device 100 shown in the above configuration example will be used as an example. Figures 5A to 8C are schematic cross-sectional views of each step in the method for manufacturing the display device illustrated below. In addition, in Figure 5A and the following, schematic cross-sectional views of the connection part 130 and its vicinity are also shown on the right side.

[0108] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), atomic layer deposition (ALD), and other methods. CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic CVD (MOCVD).

[0109] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0110] Furthermore, when processing the thin films that constitute the display device, photolithography or the like can be used. In addition, the thin films may be processed by nanoimprint lithography, sandblasting, lift-off lithography, or the like. Alternatively, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0111] There are two main methods of photolithography. One method involves forming a resist mask on the thin film to be processed, then processing the thin film by etching or other means, and removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0112] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other light sources such as ultraviolet light, KrF laser light, or ArF laser light can also be used. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light, X-rays, etc., may be used as the light source for exposure. An electron beam can also be used instead of the light source for exposure. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it enables extremely fine processing. Note that a photomask is not required when exposure is performed by scanning a beam such as an electron beam.

[0113] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0114] [Preparation of circuit board 101] As the substrate 101, a substrate having at least sufficient heat resistance to withstand subsequent heat treatment can be used. When an insulating substrate is used as the substrate 101, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, organic resin substrates, etc., can be used. In addition, semiconductor substrates such as single-crystal semiconductor substrates made of silicon, silicon carbide, etc., polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, and SOI substrates can be used.

[0115] In particular, it is preferable to use a substrate 101 on which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or insulating substrate. It is preferable that the semiconductor circuit constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), etc. In addition to the above, an arithmetic circuit, a memory circuit, etc. may also be configured.

[0116] [Formation of pixel electrodes 111R, 111G, 111B and connecting electrode 111C] Next, pixel electrodes 111R, 111G, 111B, and connecting electrode 111C are formed on the substrate 101 (Figure 5A). First, a conductive film to be used as the pixel electrode is deposited, a resist mask is formed by photolithography, and unnecessary parts of the conductive film are removed by etching. After that, the resist mask is removed to form the pixel electrodes 111R, 111G, and 111B.

[0117] When using a conductive film that is reflective to visible light as the electrode for each pixel, it is preferable to use a material (such as silver or aluminum) that has the highest possible reflectivity across the entire wavelength range of visible light. This not only improves the light extraction efficiency of the light-emitting element but also enhances color reproduction.

[0118] [Formation of insulating layer 131] Next, an insulating film 131f is formed to cover the pixel electrodes 111R, 111G, and 111B. As the insulating film 131f, a film containing a photosensitive organic resin can be used.

[0119] The insulating film 131f can be formed by a wet deposition method such as spin coating or inkjet printing. After deposition, heat treatment is performed to volatilize the solvent in the material. Alternatively, the material may be cured by heat treatment.

[0120] After forming the insulating film 131f, light 152 is irradiated using a photomask 151. Here, we show an example in which a so-called positive-type photosensitive material is used as the insulating film 131f, whose solubility in the developer improves when exposed to light.

[0121] Subsequently, developing is performed to form an insulating layer 131 (Figure 5C).

[0122] In this case, it is preferable to form the insulating layer 131 such that the pattern width of the insulating layer 131 is smaller than the pattern width of the mask pattern of the photomask 151 by adjusting the exposure time, exposure intensity, etc. in the exposure process. For example, exposure is performed under conditions where the exposure amount is greater than the appropriate value.

[0123] [Formation of insulating layer 132] Next, an insulating film 132f is formed, covering the insulating layer 131, pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, etc. (Figure 5D).

[0124] The insulating film 132f can be formed using film deposition methods such as ALD, sputtering, CVD, PLD, and vapor deposition, or a combination thereof.

[0125] Next, a resist film 141f is deposited on the insulating film 132f. Subsequently, light 153 is irradiated onto the resist film 141f using a photomask 151 (Figure 5E).

[0126] Next, the resist film 141f is subjected to a development process to form the resist mask 141 (Figure 5F).

[0127] Here, the same photomask 151 can be used for both the formation of the insulating layer 131 and the formation of the resist mask 141. It is not necessary to use strictly identical photomasks; any photomask manufactured to form the same pattern can be used. Since the photomask 151 used for forming the insulating layer 131 and the resist mask 141 can be shared, production costs can be reduced.

[0128] Furthermore, different photomasks may be used for the formation of the insulating layer 131 and the photomask used for the formation of the resist mask 141.

[0129] As shown in Figure 5F, it is preferable to form the resist mask 141 so as to encompass the insulating layer 131.

[0130] Next, the portion of the insulating film 132f not covered by the resist mask 141 is etched. Then, the resist mask 141 is removed. This forms the insulating layer 132 (Figure 5G).

[0131] [Formation of EL film 112Rf] Next, an EL film 112Rf, which will later become the EL layer 112R, is deposited on the pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, and insulating layer 132.

[0132] The EL film 112Rf has a film containing at least a luminescent compound. In addition, it may have a structure in which one or more films functioning as electron injection layers, electron transport layers, charge generation layers, hole transport layers, or hole injection layers are laminated. The EL film 112Rf can be formed by, for example, vapor deposition, sputtering, or inkjet. However, it is not limited to these, and the above-mentioned film formation methods can be used as appropriate.

[0133] As an example, it is preferable that the EL film 112Rf be a laminated film in which a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer are stacked in this order. In this case, the EL layer 114 to be formed later can be a film having an electron injection layer. In particular, by providing an electron transport layer covering the emissive layer, it is possible to suppress damage to the emissive layer during subsequent photolithography processes, etc., and a highly reliable light-emitting element can be manufactured. Furthermore, by using layers containing the same organic compound for the electron transport layer used in the EL film 112Rf, etc., and the electron injection layer used in the subsequent EL layer 114, the junction between them can be improved, resulting in a highly luminous and reliable light-emitting element. For example, an electron-transporting organic compound can be used for the electron transport layer, and a material containing the organic compound and a metal can be used for the electron injection layer.

[0134] It is preferable to form the EL film 112Rf so as not to be present on the connecting electrode 111C. For example, when forming the EL film 112Rf by vapor deposition or sputtering, it is preferable to use a shielding mask to prevent the EL film 112Rf from being deposited on the connecting electrode 111C.

[0135] [Formation of sacrificial film 144a] Next, a sacrificial film 144a is formed by covering the EL film 112Rf. The sacrificial film 144a is also provided in contact with the upper surface of the connecting electrode 111C.

[0136] The sacrificial film 144a can be a film with high resistance to etching treatment of each EL film, such as the EL film 112Rf, i.e., a film with a high etching selectivity ratio. Alternatively, the sacrificial film 144a can be a film with a high etching selectivity ratio with other sacrificial films, such as the sacrificial film 146a described later. Furthermore, it is particularly preferable that the sacrificial film 144a be a film that can be removed by a wet etching method that causes minimal damage to each EL film.

[0137] As the sacrificial film 144a, suitable examples include metal films, alloy films, metal oxide films, semiconductor films, and inorganic films such as inorganic insulating films. The sacrificial film 144a can be formed by various film deposition methods such as sputtering, vapor deposition, CVD, and ALD. In particular, since the ALD method causes little film deposition damage to the layer to be formed, it is preferable to form the sacrificial film 144a directly on the EL film 112Rf using the ALD method.

[0138] As the sacrificial film 144a, for example, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metallic materials, can be used. In particular, it is preferable to use low-melting-point materials such as aluminum or silver.

[0139] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) can be used as the sacrificial film 144a. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0140] In addition, element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium. In particular, it is preferable that M be one or more selected from gallium, aluminum, or yttrium.

[0141] Furthermore, as the sacrificial film 144a, oxides such as aluminum oxide, hafnium oxide, and silicon oxide, nitrides such as silicon nitride and aluminum nitride, or oxynitrides such as silicon oxynitride can be used. Such inorganic insulating materials can be formed using film deposition methods such as sputtering, CVD, or ALD, but it is particularly preferable to use the ALD method for the sacrificial film 144a that is formed directly on the EL film 112Rf.

[0142] Furthermore, as the sacrificial film 144a, a material that is soluble in a chemically stable solvent may be used, at least for the film located on the uppermost part of the EL film 112Rf. In particular, a material soluble in water or alcohol can be suitably used for the sacrificial film 144a. When forming the sacrificial film 144a, it is preferable to apply it using a wet deposition method while dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the EL film 112Rf.

[0143] Wet film deposition methods that can be used to form the sacrificial film 144a include spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0144] As the sacrificial film 144a, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used.

[0145] [Formation of sacrificial film 146a] Next, a sacrificial film 146a is formed on the sacrificial film 144a (Figure 6A).

[0146] The sacrificial film 146a is used as a hard mask when etching the sacrificial film 144a later. Also, when processing the sacrificial film 146a later, the sacrificial film 144a will be exposed. Therefore, the sacrificial film 144a and the sacrificial film 146a are selected as a combination of films with a high etching selectivity ratio for each other. Thus, depending on the etching conditions for the sacrificial film 144a and the sacrificial film 146a, the film that can be used for the sacrificial film 146a can be selected.

[0147] For example, when dry etching using a fluorine-containing gas (also called a fluorine-based gas) is used to etch the sacrificial film 146a, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, or an alloy containing molybdenum and tungsten can be used for the sacrificial film 146a. In the dry etching using the above-mentioned fluorine-based gas, films that allow for a large selectivity ratio between the sacrificial layer 146a and etching (i.e., a slower etching rate) include metal oxide films such as IGZO and ITO, which can be used for the sacrificial film 144a.

[0148] However, the sacrificial film 146a can be selected from a variety of materials depending on the etching conditions of the sacrificial film 144a and the sacrificial film 146a. For example, it can be selected from films that can be used for the sacrificial film 144a.

[0149] For example, an oxide film can be used as the sacrificial film 146a. Typically, oxide films or oxynitride films such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, and hafnium oxynitride can be used.

[0150] Furthermore, a nitride film can be used as the sacrificial film 146a, for example. Specifically, nitride films such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, and germanium nitride can be used.

[0151] For example, it is preferable to use an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the sacrificial film 144a, and to use an indium-containing metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) formed by the sputtering method as the sacrificial film 146a.

[0152] Furthermore, an organic film that can be used for EL films 112Rf, etc., may be used as the sacrificial film 146a. For example, the same organic film used for EL films 112Rf, EL films 112Gf, or EL films 112Bf can be used for the sacrificial film 146a. Using such an organic film is preferable because it allows the same deposition equipment to be used for both the EL film 112Rf and the EL film 112Bf. Moreover, the sacrificial layer can be used as a mask to simultaneously remove the EL film 112Rf, etc., during etching, thus simplifying the process.

[0153] [Formation of resist mask 143a] Next, a resist mask 143a is formed on the sacrificial film 146a at a position overlapping with the pixel electrode 111R and at a position overlapping with the connecting electrode 111C, respectively (Figure 6B).

[0154] The resist mask 143a can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0155] In this case, if a resist mask 143a is formed on the sacrificial film 144a without a sacrificial film 146a, there is a risk that the EL film 112Rf may dissolve due to the solvent of the resist material if defects such as pinholes exist in the sacrificial film 144a. Using a sacrificial film 146a prevents such problems from occurring.

[0156] Furthermore, in cases where a sacrificial film 144a is used that is less prone to defects such as pinholes, or when the EL film 112Rf is made of a material that does not dissolve in the solvent of the resist material, the resist mask 143a may be formed directly on the sacrificial film 144a without using the sacrificial film 146a.

[0157] [Etching of sacrificial film 146a] Next, the portion of the sacrificial film 146a not covered by the resist mask 143a is removed by etching to form island-shaped or strip-shaped sacrificial layers 147a (Figure 6C). At the same time, a sacrificial layer 147a is also formed on the connecting electrode 111C.

[0158] When etching the sacrificial film 146a, it is preferable to use etching conditions with a high selectivity ratio so that the sacrificial film 144a is not removed by the etching. The sacrificial film 146a can be etched by wet etching or dry etching, but using dry etching can suppress the reduction of the pattern of the sacrificial film 146a.

[0159] [Removal of resist mask 143a] Next, remove the resist mask 143a (Figure 6D).

[0160] The resist mask 143a can be removed by wet etching or dry etching. In particular, it is preferable to remove the resist mask 143a by dry etching (also called plasma ashing) using oxygen gas as the etching gas.

[0161] In this case, the removal of the resist mask 143a is performed while the EL film 112Rf is covered by the sacrificial film 144a, thus suppressing the impact on the EL film 112Rf. In particular, since contact with oxygen can adversely affect the electrical properties of the EL film 112Rf, this method is suitable when etching is performed using oxygen gas, such as plasma ashing.

[0162] [Etching of sacrificial film 144a] Next, using the sacrificial layer 147a as a mask, the portion of the sacrificial film 144a not covered by the sacrificial layer 147a is removed by etching to form island-shaped or strip-shaped sacrificial layers 145a (Figure 6E). At the same time, a sacrificial layer 145a is also formed on the connecting electrode 111C.

[0163] The sacrificial film 144a can be etched by wet etching or dry etching, but dry etching is preferred because it can suppress pattern reduction.

[0164] [Etching of EL film 112Rf] Next, a portion of the EL film 112Rf not covered by the sacrificial layer 145a is removed by etching to form island-shaped or strip-shaped EL layers 112R (Figure 6F). Etching of the EL film 112Rf exposes the upper surfaces of the pixel electrode 111G, the pixel electrode 111B, and the insulating layer 132.

[0165] In particular, for etching the EL film 112Rf, it is preferable to use dry etching with an etching gas that does not contain oxygen as its main component. This suppresses the deterioration of the EL film 112Rf and enables the realization of a highly reliable display device. Examples of etching gases that do not contain oxygen as their main component include noble gases such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, H2, or He. Alternatively, a mixed gas of the above gases and an oxygen-free diluent gas can be used as the etching gas.

[0166] Furthermore, etching of the EL film 112Rf is not limited to the above; it may also be performed by dry etching using other gases or by wet etching.

[0167] Furthermore, using an etching gas containing oxygen gas, or dry etching using oxygen gas, for etching the EL film 112Rf can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently fast etching rate, thereby reducing etching damage. In addition, defects such as the adhesion of reaction products generated during etching can be suppressed. For example, an etching gas to which oxygen gas is added to the above-mentioned etching gas that does not primarily contain oxygen can be used.

[0168] During etching of the EL film 112Rf, the insulating layer 132 is exposed. Therefore, it is preferable to use a film for the insulating layer 132 that is highly resistant to etching (difficult to etch) of the EL film 112Rf. Note that during etching of the EL film 112Rf, the upper part of the insulating layer 132 may be etched, and the portion not covered by the EL layer 112R may become thin.

[0169] Furthermore, the sacrificial layer 147a may be etched simultaneously with the EL film 112Rf. Etching the EL film 112Rf and the sacrificial layer 147a using the same process simplifies the process and reduces the manufacturing cost of the display device, which is therefore preferable.

[0170] [Formation of EL film 112Gf] Next, an EL film 112Gf, which will later become the EL layer 112G, is formed on the sacrificial layer 147a, the insulating layer 132, the pixel electrode 111G, and the pixel electrode 111B. At this time, it is preferable not to provide the EL film 112Gf on the connecting electrode 111C, similar to the EL film 112Rf described above.

[0171] The method for forming the EL film 112Gf can be described by referring to the description of the EL film 112Rf above.

[0172] [Formation of sacrificial film 144b] Next, a sacrificial film 144b is formed on the EL film 112Gf. The sacrificial film 144b can be formed in the same manner as the sacrificial film 144a. In particular, it is preferable to use the same material for the sacrificial film 144b as for the sacrificial film 144a.

[0173] At the same time, a sacrificial film 144a is formed on the connecting electrode 111C, covering the sacrificial layer 147a.

[0174] [Formation of sacrificial film 146b] Next, a sacrificial film 146b is formed on the sacrificial film 144b (Figure 7A). The sacrificial film 146b can be formed in the same manner as the sacrificial film 146a. In particular, it is preferable to use the same material for the sacrificial film 146b as for the sacrificial film 146a.

[0175] [Formation of resist mask 143b] Next, a resist mask 143b is formed on the sacrificial film 146b in a region that overlaps with the pixel electrode 111G (Figure 7B).

[0176] The resist mask 143b can be formed in the same manner as the resist mask 143a.

[0177] In this case, since the connecting electrode 111C is protected by sacrificial layers 145a and 147a, it is not necessary to form a resist mask 143b. Alternatively, the resist mask 143b may be provided to cover the connecting electrode 111C.

[0178] The resist mask 143b can be formed in the same manner as the resist mask 143a.

[0179] [Etching of sacrificial film 146b] Next, the portion of the sacrificial film 146b not covered by the resist mask 143b is removed by etching to form island-shaped or strip-shaped sacrificial layers 147b (Figure 7C). At the same time, the sacrificial film 146b on the connecting electrode 111C is also removed by etching.

[0180] For etching of the sacrificial film 146b, the description of the sacrificial film 146a above can be applied.

[0181] [Removal of resist mask 143b] Next, remove the resist mask 143b. The removal of resist mask 143b can be done by referring to the description of resist mask 143a above.

[0182] [Etching of sacrificial film 144b] Next, using the sacrificial layer 147b as a mask, the portion of the sacrificial film 144b not covered by the sacrificial layer 147b is removed by etching to form island-shaped or strip-shaped sacrificial layers 145b. At the same time, the sacrificial film 144b on the connecting electrode 111C is also removed by etching.

[0183] The etching of the sacrificial film 144b can be performed by referring to the description of the sacrificial film 144a above.

[0184] [Etching of EL film 112Gf] Next, a portion of the EL film 112Gf not covered by the sacrificial layer 145b is removed by etching to form island-shaped or strip-shaped EL layers 112G (Figure 7D).

[0185] The etching of the EL film 112Gf can be performed by referring to the description of the EL film 112Rf above.

[0186] At this time, the EL layer 112R and the connecting electrode 111C are protected by the sacrificial layer 145a and the sacrificial layer 147a, so that they are not damaged during the etching process of the EL film 112Gf.

[0187] In this way, island-shaped or strip-shaped EL layers 112R and island-shaped or strip-shaped EL layers 112G can be manufactured with high positional accuracy.

[0188] [Formation of EL layer 112B] By performing the above steps on the EL film 112Bf (not shown), island-shaped or strip-shaped EL layers 112B, a sacrificial layer 145c, and a sacrificial layer 147c can be formed (Figure 7E).

[0189] Specifically, after the formation of the EL layer 112G, the EL film 112Bf, sacrificial film 144c, sacrificial film 146c, and resist mask 143c (none of which are shown) are formed in order. Subsequently, the sacrificial film 146c is etched to form a sacrificial layer 147c (not shown), and then the resist mask 143c is removed. Next, the sacrificial film 144c is etched to form a sacrificial layer 145c. After that, the EL film 112Bf is etched to form island-shaped or strip-shaped EL layers 112B.

[0190] [Removal of the sacrificial layer] Next, sacrificial layers 147a, 147b, 147c, 145a, 145b, and 145c are removed, exposing the upper surfaces of EL layers 112R, 112G, and 112B (Figure 8A). At the same time, the upper surface of the connecting electrode 111C is also exposed.

[0191] It is preferable that the etching of sacrificial layers 147a, 147b, and 147c (hereinafter collectively referred to as sacrificial layer 147) and the etching of sacrificial layers 145a, 145b, and 145c (hereinafter collectively referred to as sacrificial layer 145) be carried out in the same process.

[0192] The etching of sacrificial layer 147 and sacrificial layer 145 may be carried out in different processes. In this case, sacrificial layer 147 is etched first, followed by sacrificial layer 145.

[0193] Alternatively, the sacrificial layer 147 may be lifted off by etching the sacrificial layer 145 by isotropic etching (e.g., wet etching).

[0194] Sacrificial layers 145 and 147 can be removed by wet etching or dry etching. In this case, it is preferable to use a method that minimizes damage to EL layers 112R, EL layer 112G, and EL layer 112B. Wet etching is particularly preferred. For example, wet etching using an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof is preferred.

[0195] Alternatively, it is preferable to remove either or both of the sacrificial layer 145 and the sacrificial layer 147 by dissolving them in a solvent such as water or alcohol. Here, various alcohols can be used as the alcohol that can dissolve the sacrificial layer 145 or the sacrificial layer 147, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0196] After removing sacrificial layers 145 and 147, it is preferable to perform a drying treatment to remove water contained inside EL layers 112R, EL layer 112G, and EL layer 112B, as well as water adsorbed on the surface. For example, it is preferable to perform a heat treatment under an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0197] In this way, EL layer 112R, EL layer 112G, and EL layer 112B can be manufactured separately.

[0198] [Formation of EL layer 114] Next, EL layer 114 is formed to cover EL layer 112R, EL layer 112G, and EL layer 112B.

[0199] The EL layer 114 can be deposited using the same method as the EL film 112Rf. When depositing the EL layer 114 by vapor deposition, it is preferable to use a shielding mask to prevent the EL layer 114 from being deposited on the connecting electrode 111C.

[0200] [Formation of common electrode 113] Next, the common electrode 113 is formed by covering the EL layer 114 and the connecting electrode 111C (Figure 8B).

[0201] The common electrode 113 can be formed by a film deposition method such as vapor deposition or sputtering. Alternatively, a film formed by vapor deposition and a film formed by sputtering may be laminated together. In this case, it is preferable to form the common electrode 113 so as to encompass the region where the EL layer 114 is formed. That is, the edges of the EL layer 114 can overlap with the common electrode 113. It is preferable to form the common electrode 113 using a shielding mask.

[0202] Furthermore, the common electrode 113 is electrically connected to the connecting electrode 111C outside the display area.

[0203] [Formation of protective layer 121] Next, a protective layer 121 is formed on the common electrode 113. For forming the inorganic insulating film used in the protective layer 121, sputtering, PECVD, or ALD methods are preferred. The ALD method is particularly preferred because it offers excellent step coverage and is less prone to defects such as pinholes. Furthermore, for forming the organic insulating film, the inkjet method is preferred because it allows for the formation of a uniform film in the desired area.

[0204] Based on the above, the display device 100 shown in Figures 1B and 1C can be manufactured.

[0205] In the above example, the common electrode 113 and the EL layer 114 were formed with different upper surface shapes, but they may also be formed in the same region.

[0206] Figure 9A shows a schematic cross-sectional view after the sacrificial layer has been removed. Subsequently, as shown in Figure 9B, the EL layer 114 and the common electrode 113 are formed using the same shielding mask, or without using a shielding mask. This reduces manufacturing costs compared to using different shielding masks.

[0207] In this case, as shown in Figure 9B, the connection portion 130 has a configuration in which an EL layer 114 is sandwiched between the connecting electrode 111C and the common electrode 113. In this case, it is preferable to use a material with the lowest possible electrical resistance for the EL layer 114. Alternatively, it is preferable to reduce the electrical resistance in the thickness direction of the EL layer 114 by forming it as thin as possible. For example, by using an electron-injection or hole-injection material with a thickness of 1 nm to 5 nm, preferably 1 nm to 3 nm, for the EL layer 114, the electrical resistance between the connecting electrode 111C and the common electrode 113 can be reduced to a negligible degree.

[0208] Next, as shown in Figure 9C, a protective layer 121 is formed. At this time, it is preferable to provide the protective layer 121 so as to cover the ends of the common electrode 113 and the ends of the EL layer 114, as shown in Figure 9C. This effectively prevents the diffusion of impurities such as water or oxygen from the outside to the EL layer 114 and the interface between the EL layer 114 and the common electrode 113.

[0209] The above is an explanation of an example of a method for manufacturing a display device.

[0210] [Differentiation] The following describes an example with a slightly different structure from the one described above. Note that parts that overlap with the above will be referenced and explained in more detail below.

[0211] [Variation 1] Figures 10A and 10B show schematic cross-sectional views of the display device 100A. The top view of the display device 100A is the same as in Figure 1A. Figure 10A corresponds to the cross-section in the X direction, and Figure 8B corresponds to the cross-section in the Y direction.

[0212] The display device 100A differs from the display device 100 in that it does not have a common layer, the EL layer 114.

[0213] The common electrode 113 is provided in contact with the upper surfaces of the EL layer 112R, EL layer 112G, and EL layer 112B. By omitting the EL layer 114, it becomes possible to make the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B each have completely different laminated structures, thus increasing the range of material choices and improving design flexibility.

[0214] The display device 100B shown in Figure 10C is an example in which the EL layer and common electrode 113 are processed continuously without being interrupted between light-emitting elements of the same color arranged in the Y direction. In other words, in the display device 100B, each EL layer and common electrode 113 is processed to have a strip-shaped upper surface.

[0215] [Variation 2] The display device 100C shown in Figures 11A and 11B differs from the above-mentioned display device 100, etc., mainly in the configuration of the light-emitting element.

[0216] The light-emitting element 110R has an optical adjustment layer 115R between the pixel electrode 111R and the EL layer 112R. The light-emitting element 110G has an optical adjustment layer 115G between the pixel electrode 111G and the EL layer 112G. The light-emitting element 110B has an optical adjustment layer 115B between the pixel electrode 111B and the EL layer 112B.

[0217] Optical adjustment layers 115R, 115G, and 115B each correspond to the conductive layer 111b exemplified in Figure 4A, etc. In this case, pixel electrodes 111R, 111G, and 111B each correspond to the conductive layer 111a.

[0218] Furthermore, optical adjustment layers 115R, 115G, and 115B are all transparent to visible light. The optical adjustment layers 115R, 115G, and 115B each have different thicknesses. This allows for different optical path lengths for each light-emitting element.

[0219] Here, a conductive film reflective to visible light is used for the pixel electrodes 111R, 111G, and 111B, and a conductive film reflective and transmittant to visible light is used for the common electrode 113. As a result, each light-emitting element realizes a so-called microcavity structure (micro-resonator structure), which intensifies light of a specific wavelength. This makes it possible to realize a display device with improved color purity.

[0220] Each optical adjustment layer can be made of a conductive material that is transparent to visible light. For example, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, indium tin oxide containing silicon, and indium zinc oxide containing silicon can be used.

[0221] Each optical adjustment layer can be formed after the pixel electrodes 111R, 111G, and 111B have been formed, but before the EL film 112Rf, etc., is formed. Each optical adjustment layer may use conductive films of different thicknesses, or it may be arranged in a single-layer structure, a two-layer structure, a three-layer structure, etc., from thinnest to thickest.

[0222] Furthermore, the display device 100D shown in Figure 11C is an example in which a strip-shaped EL layer extending in the Y direction and a common electrode 113 are applied to the above-mentioned display device 100C. Figure 11C shows a cross-section of two light-emitting elements 110G arranged side by side in the Y direction.

[0223] [Example 3] The display device 100E shown in Figures 12A and 12B differs from the display device 100C in that it does not have an optical adjustment layer.

[0224] Display device 100E is an example of realizing a microcavity structure by varying the thickness of the EL layer 112R, EL layer 112G, and EL layer 112B. This configuration eliminates the need for a separate optical adjustment layer, thus simplifying the manufacturing process.

[0225] For example, in the display device 100E, the EL layer 112R of the light-emitting element 110R, which emits the longest wavelength light, is the thickest, and the EL layer 112B of the light-emitting element 110B, which emits the shortest wavelength light, is the thinnest. However, this is not limited to this, and the thickness of each EL layer can be adjusted by considering the wavelength of light emitted by each light-emitting element, the optical properties of the layers constituting the light-emitting element, and the electrical properties of the light-emitting element.

[0226] Furthermore, the display device 100F shown in Figure 12C is an example in which a strip-shaped EL layer extending in the Y direction and a common electrode 113 are applied to the above-mentioned display device 100E. Figure 12C shows a cross-section of two light-emitting elements 110G arranged side by side in the Y direction.

[0227] The above is an explanation of the variations.

[0228] Although the above-described modified examples 2 and 3 show examples in which the EL layer 114 is used, a configuration without the EL layer 114 is also possible.

[0229] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0230] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0231] (Embodiment 2) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention.

[0232] The display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, smartphones, smartwatches, tablet devices, personal digital assistants, and audio playback devices.

[0233] [Display device 400A] Figure 13 shows a perspective view of the display device 400A, and Figure 14A shows a cross-sectional view of the display device 400A.

[0234] The display device 400A has a configuration in which substrate 452 and substrate 451 are bonded together. In Figure 13, substrate 452 is clearly indicated by a dashed line.

[0235] The display device 400A includes a display unit 462, a circuit 464, wiring 465, etc. Figure 13 shows an example in which IC 473 and FPC 472 are mounted on the display device 400A. Therefore, the configuration shown in Figure 13 can also be described as a display module having the display device 400A, an IC (integrated circuit), and an FPC.

[0236] For example, a scan line drive circuit can be used as circuit 464.

[0237] Wiring 465 has the function of supplying signals and power to the display unit 462 and the circuit 464. These signals and power are input to wiring 465 from an external source via FPC 472 or from IC 473.

[0238] Figure 13 shows an example in which IC 473 is mounted on the substrate 451 using a COG (Chip On Glass) method or COF (Chip On Film) method. IC 473 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 400A and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC using a COF method or the like.

[0239] Figure 14A shows an example of a cross-section obtained by cutting a portion of the display device 400A, including the FPC 472, a portion of the circuit 464, a portion of the display unit 462, and a portion of the area including the end.

[0240] The display device 400A shown in Figure 14A has a transistor 201, a transistor 205, a light-emitting element 430a that emits red light, a light-emitting element 430b that emits green light, and a light-emitting element 430c that emits blue light, etc., between substrates 451 and 452.

[0241] The light-emitting elements 430a, 430b, and 430c can be the light-emitting elements exemplified in Embodiment 1.

[0242] Here, if the pixels of the display device have three types of subpixels, each having a light-emitting element that emits a different color from the others, examples of these three subpixels include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of these four subpixels include subpixels of four colors: R, G, B, and white (W); and subpixels of four colors: R, G, B, and Y.

[0243] The protective layer 416 and the substrate 452 are bonded together via an adhesive layer 442. For sealing the light-emitting element, a solid sealing structure or a hollow sealing structure can be applied. In Figure 14A, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 is filled with an inert gas (such as nitrogen or argon), indicating a hollow sealing structure. The adhesive layer 442 may be provided overlapping the light-emitting element. Alternatively, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 may be filled with a resin different from the adhesive layer 442.

[0244] The light-emitting elements 430a, 430b, and 430c have an optical adjustment layer between the pixel electrode and the EL layer. Light-emitting element 430a has an optical adjustment layer 426a, light-emitting element 430b has an optical adjustment layer 426b, and light-emitting element 430c has an optical adjustment layer 426c. For details of the light-emitting elements, please refer to Embodiment 1.

[0245] The pixel electrodes 411a, 411b, and 411c are each connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214.

[0246] The edges of the pixel electrodes and optical adjustment layer are covered by insulating layer 421 and insulating layer 422. Insulating layer 421 contains an organic resin, and insulating layer 422 contains an inorganic insulating film. The pixel electrodes also contain a material that reflects visible light, and the counter electrodes contain a material that transmits visible light.

[0247] The light emitted by the light-emitting element is directed towards the substrate 452. It is preferable to use a material with high transmittance to visible light for the substrate 452.

[0248] Both transistors 201 and 205 are formed on the substrate 451. These transistors can be manufactured using the same materials and processes.

[0249] On the substrate 451, an insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided in this order. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. A part of the insulating layer 213 functions as a gate insulating layer of each transistor. The insulating layer 215 is provided to cover the transistors. The insulating layer 214 is provided to cover the transistors and has a function as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0250] It is preferable to use a material in which impurities such as water and hydrogen hardly diffuse in at least one of the insulating layers covering the transistors. Thereby, the insulating layer can function as a barrier layer. By adopting such a configuration, diffusion of impurities from the outside into the transistors can be effectively suppressed, and the reliability of the display device can be improved.

[0251] As the insulating layer 211, the insulating layer 213, and the insulating layer 215, it is preferable to use an inorganic insulating film respectively. As the inorganic insulating film, for example, a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, an aluminum nitride film, etc. can be used. Further, a hafnium oxide film, a yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, etc. may be used. Further, two or more of the above-mentioned inorganic insulating films may be laminated and used.

[0252] Here, the organic insulating film often has a lower barrier property than the inorganic insulating film. Therefore, it is preferable that the organic insulating film has an opening near the end of the display device 400A. Thereby, it is possible to suppress the entry of impurities from the end of the display device 400A through the organic insulating film. Alternatively, the organic insulating film may be formed such that the end of the organic insulating film is inside the end of the display device 400A so that the organic insulating film is not exposed at the end of the display device 400A.

[0253] As the insulating layer 214 that functions as a planarization layer, an organic insulating film is suitable. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimide amide resin, siloxane resin, benzocyclobutene-based resin, phenol resin, and precursors of these resins.

[0254] In the region 228 shown in FIG. 14A, an opening is formed in the insulating layer 214. Thereby, even when an organic insulating film is used for the insulating layer 214, it is possible to suppress impurities from entering the display unit 462 from the outside through the insulating layer 214. Therefore, the reliability of the display device 400A can be improved.

[0255] The transistor 201 and the transistor 205 include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is given to a plurality of layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0256] The structure of the transistor included in the display device of the present embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverse staggered transistor, or the like can be used. Also, either a top gate type or a bottom gate type transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0257] Transistors 201 and 205 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0258] The crystallinity of the semiconductor material used in the semiconductor layer of the transistor is not particularly limited; amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystalline properties other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors having crystalline regions in part) may be used. Using a single-crystal semiconductor or a semiconductor with crystalline properties is preferable because it can suppress the degradation of transistor characteristics.

[0259] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor (hereinafter referred to as an OS transistor) that uses a metal oxide in the channel formation region.

[0260] The band gap of the metal oxide used in the semiconductor layer of the transistor is preferably 2 eV or more, and more preferably 2.5 eV or more. By using a metal oxide with a large band gap, the off-current of the OS transistor can be reduced.

[0261] The metal oxide preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc. In particular, M is preferably one or more selected from gallium, aluminum, yttrium, and tin, and gallium is more preferred. A metal oxide containing indium, M, and zinc may hereafter be referred to as In-M-Zn oxide.

[0262] When the metal oxide is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is equal to or greater than the atomic ratio of M. Examples of such In-M-Zn oxide atomic ratios of metal elements include compositions where In:M:Zn=1:1:1 or close to it, In:M:Zn=1:1:1.2 or close to it, In:M:Zn=2:1:3 or close to it, In:M:Zn=3:1:2 or close to it, In:M:Zn=4:2:3 or close to it, In:M:Zn=4:2:4.1 or close to it, In:M:Zn=5:1:3 or close to it, In:M:Zn=5:1:6 or close to it, In:M:Zn=5:1:7 or close to it, In:M:Zn=5:1:8 or close to it, In:M:Zn=6:1:6 or close to it, In:M:Zn=5:2:5 or close to it, and so on. Note that "close to it" compositions include a range of ±30% of the desired atomic ratio. By increasing the atomic ratio of indium in a metal oxide, the on-current or field-effect mobility of a transistor can be increased.

[0263] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, with In being 4, Ga is between 1 and 3, and Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, with In being 5, Ga is greater than 0.1 and 2 or less, and Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, with In being 1, Ga is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0264] Furthermore, the atomic ratio of In in an In-M-Zn oxide may be less than the atomic ratio of M. Examples of such atomic ratios of metal elements in an In-M-Zn oxide include compositions where In:M:Zn = 1:3:2 or close to it, In:M:Zn = 1:3:3 or close to it, In:M:Zn = 1:3:4 or close to it, etc. By increasing the atomic ratio of M in the metal oxide, it is possible to increase the band gap of the In-M-Zn oxide and improve its resistance to photo-negative bias stress testing. Specifically, it is possible to reduce the change in threshold voltage or the change in shift voltage (Vsh) measured in the NBTIS (Negative Bias Temperature Illumination Stress) test of a transistor. Note that the shift voltage (Vsh) is defined as the Vg at which the tangent line at the point where the slope of the drain current (Id)-gate voltage (Vg) curve is maximum intersects the straight line where Id = 1 pA.

[0265] Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0266] Alternatively, the semiconductor layer of a transistor may have a layered material that functions as a semiconductor. A layered material is a general term for a group of materials having a layered crystalline structure. A layered crystalline structure is a structure in which layers formed by covalent or ionic bonds are stacked via weaker bonds than covalent or ionic bonds, such as van der Waals forces. Layered materials have high electrical conductivity within a unit layer, that is, high two-dimensional electrical conductivity. By using a material that functions as a semiconductor and has high two-dimensional electrical conductivity in the channel formation region, a transistor with a large on-current can be provided.

[0267] Examples of the above-mentioned layered materials include graphene, silicene, and chalcogenides. Chalcogenides are compounds containing chalcogens (elements belonging to Group 16). Examples of chalcogenides include transition metal chalcogenides and Group 13 chalcogenides. Specific examples of transition metal chalcogenides applicable as semiconductor layers in transistors include molybdenum sulfide (typically MoS2), molybdenum selenide (typically MoSe2), molybdenum tellurium (typically MoTe2), tungsten sulfide (typically WS2), tungsten selenide (typically WSe2), tungsten tellurium (typically WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically HfSe2), zirconium sulfide (typically ZrS2), and zirconium selenide (typically ZrSe2).

[0268] The transistors in circuit 464 and the transistors in display unit 462 may have the same structure or different structures. The structures of the multiple transistors in circuit 464 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in display unit 462 may all be the same or there may be two or more different structures.

[0269] A connection portion 204 is provided in the region of substrate 451 where substrate 452 does not overlap. At the connection portion 204, wiring 465 is electrically connected to FPC 472 via conductive layer 466 and connection layer 242. The conductive layer 466 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as the pixel electrode and a conductive film obtained by processing the same conductive film as the optical adjustment layer. The conductive layer 466 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and FPC 472 to be electrically connected via the connection layer 242.

[0270] It is preferable to provide a light-shielding layer 417 on the surface of the substrate 452 that faces the substrate 451. Various optical components can also be arranged on the outside of the substrate 452. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-collecting films. Furthermore, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may also be arranged on the outside of the substrate 452.

[0271] By providing a protective layer 416 that covers the light-emitting element, it is possible to suppress the ingress of impurities such as water into the light-emitting element and improve the reliability of the light-emitting element.

[0272] In the region 228 near the edge of the display device 400A, it is preferable that the insulating layer 215 and the protective layer 416 are in contact with each other through an opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 416 are in contact with each other. This makes it possible to suppress the entry of impurities into the display unit 462 from the outside through the organic insulating film. Therefore, the reliability of the display device 400A can be improved.

[0273] Figure 14B shows an example where the protective layer 416 has a three-layer structure. In Figure 14B, the protective layer 416 has an inorganic insulating layer 416a on the light-emitting element 430c, an organic insulating layer 416b on the inorganic insulating layer 416a, and an inorganic insulating layer 416c on the organic insulating layer 416b.

[0274] The inorganic insulating layer 416a and the inorganic insulating layer 416c extend outside the end of the organic insulating layer 416b and are in contact with each other. In a region where no common electrode is provided, the inorganic insulating layer 416a and the insulating layer 422 are in contact with each other. And the insulating layer 422 is in contact with the insulating layer 215 (inorganic insulating layer) through an opening of the insulating layer 214 (organic insulating layer). Thus, since the insulating layer 215 and the protective layer 416 can surround the light-emitting element, the reliability of the light-emitting element can be enhanced.

[0275] Thus, the protective layer 416 may have a laminated structure of an organic insulating film and an inorganic insulating film. At this time, it is preferable that the inorganic insulating film extends outside the organic insulating film.

[0276] For the substrates 451 and 452, glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc. can be used respectively. For the substrate on the side where light from the light-emitting element is extracted, a material that transmits the light is used. If a flexible material is used for the substrates 451 and 452, the flexibility of the display device can be enhanced. Also, a polarizing plate may be used as the substrate 451 or the substrate 452.

[0277] As the substrates 451 and 452, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. can be used respectively. Glass with a thickness that has flexibility may be used for one or both of the substrates 451 and 452.

[0278] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0279] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0280] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0281] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0282] Various types of curing adhesives can be used as the adhesive layer, including UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0283] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0284] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0285] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used for conductive layers of various wirings and electrodes that constitute a display device, and for conductive layers of light-emitting elements (conductive layers that function as pixel electrodes or common electrodes).

[0286] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0287] [Display device 400B] Figure 15A shows a cross-sectional view of the display device 400B. The perspective view of the display device 400B is the same as that of the display device 400A shown in Figure 13. Figure 15A shows examples of cross-sections of the display device 400B when a portion of the area including the FPC 472, a portion of the circuit 464, and a portion of the display unit 462 are cut. In Figure 15A, an example of a cross-section is shown when a portion of the display unit 462, in particular, including the green light-emitting element 430b and the blue light-emitting element 430c, is cut. Note that explanations of parts that are the same as those of the display device 400A may be omitted.

[0288] The display device 400B shown in Figure 15A has transistors 202, 210, light-emitting elements 430b, and 430c between substrates 453 and 454.

[0289] The substrate 454 and the protective layer 416 are bonded together via an adhesive layer 442. The adhesive layer 442 is provided in overlap with the light-emitting elements 430b and 430c, respectively, and a solid encapsulation structure is applied to the display device 400B.

[0290] The substrate 453 and the insulating layer 212 are bonded together by an adhesive layer 455.

[0291] The method for manufacturing the display device 400B involves first bonding a fabrication substrate, on which an insulating layer 212, transistors, light-emitting elements, etc., are provided, to a substrate 454 on which a light-shielding layer 417 is provided, using an adhesive layer 442. Then, the fabrication substrate is peeled off and a substrate 453 is attached to the exposed surface, thereby transferring the components formed on the fabrication substrate to the substrate 453. It is preferable that both the substrate 453 and the substrate 454 are flexible. This increases the flexibility of the display device 400B.

[0292] The insulating layer 212 can be made of an inorganic insulating film that can be used for insulating layer 211, insulating layer 213, and insulating layer 215, respectively.

[0293] The pixel electrodes are connected to the conductive layer 222b of the transistor 210 through an opening provided in the insulating layer 214. The transistor 210 has the function of controlling the driving of the light-emitting element.

[0294] The ends of the pixel electrodes are covered by insulating layers 421 and 422.

[0295] The light emitted by the light-emitting elements 430b and 430c is emitted towards the substrate 454. It is preferable to use a material with high transmittance to visible light for the substrate 454.

[0296] A connection portion 204 is provided in the region of substrate 453 that does not overlap with substrate 454. At the connection portion 204, wiring 465 is electrically connected to FPC 472 via conductive layer 466 and connection layer 242. The conductive layer 466 can be obtained by processing the same conductive film as the pixel electrode. This allows the connection portion 204 and FPC 472 to be electrically connected via the connection layer 242.

[0297] Transistors 202 and 210 each have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel forming region 231i.

[0298] The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n via openings provided in the insulating layer 215. Of the conductive layer 222a and the conductive layer 222b, one functions as a source and the other functions as a drain.

[0299] Figure 15A shows an example in which the insulating layer 225 covers the top and sides of the semiconductor layer. The conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and insulating layer 215, respectively.

[0300] On the other hand, in the transistor 209 shown in Figure 15B, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231, but does not overlap with the low-resistance region 231n. For example, the structure shown in Figure 15B can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 15B, an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layers 222a and 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215. Furthermore, an insulating layer 218 covering the transistor may also be provided.

[0301] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0302] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0303] (Embodiment 3) In this embodiment, a light-emitting element (also called a light-emitting device) that can be used in a display device according to one aspect of the present invention will be described.

[0304] In this specification, devices fabricated using a metal mask or an FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or an FMM may be referred to as MML (Metal Maskless) structured devices.

[0305] In this specification, a structure in which different light-emitting layers are created or painted for each color of light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. Also, in this specification, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0306] Furthermore, light-emitting devices can be broadly classified into single-structure and tandem-structure devices. A single-structure device has one light-emitting unit between a pair of electrodes, and it is preferable that this light-emitting unit includes one or more light-emitting layers. To obtain white light emission in a single-structure device, one should select light-emitting layers such that the light emitted from each of the two or more layers is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a configuration that emits white light as a whole can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0307] A tandem device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. By using light-emitting layers that emit light of the same color in each light-emitting unit, the brightness per given current can be increased, and a more reliable light-emitting device can be achieved compared to a single structure. To obtain white light emission in a tandem structure, the light from the light-emitting layers of multiple light-emitting units can be combined to produce white light emission. The combination of light-emitting colors that produces white light emission is the same as that for a single structure. In a tandem device, it is preferable to provide an intermediate layer, such as a charge-generating layer, between the multiple light-emitting units.

[0308] Furthermore, when comparing the aforementioned white light-emitting devices (single or tandem structure) with SBS structure light-emitting devices, SBS structure light-emitting devices can consume less power than white light-emitting devices. If you want to keep power consumption low, it is preferable to use SBS structure light-emitting devices. On the other hand, white light-emitting devices are preferable because their manufacturing process is simpler than that of SBS structure light-emitting devices, which can lead to lower manufacturing costs or higher manufacturing yields.

[0309] <Example of light-emitting element configuration> As shown in Figure 16A, the light-emitting element has an EL layer 23 between a pair of electrodes (lower electrode 21, upper electrode 25). The EL layer 23 can be composed of multiple layers, such as layer 4420, light-emitting layer 4411, and layer 4430. Layer 4420 may include, for example, a layer containing a material with high electron injection properties (electron injection layer) and a layer containing a material with high electron transport properties (electron transport layer). Light-emitting layer 4411 may include, for example, a light-emitting compound. Layer 4430 may include, for example, a layer containing a material with high hole injection properties (hole injection layer) and a layer containing a material with high hole transport properties (hole transport layer).

[0310] A configuration having a layer 4420, an emissive layer 4411, and a layer 4430 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 16A is referred to as a single structure.

[0311] Furthermore, Figure 16B shows a modified example of the EL layer 23 of the light-emitting element 20 shown in Figure 16A. Specifically, the light-emitting element 20 shown in Figure 16B has a layer 4430-1 on the lower electrode 21, a layer 4430-2 on layer 4430-1, a light-emitting layer 4411 on layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on layer 4420-1, and an upper electrode 25 on layer 4420-2. For example, when the lower electrode 21 is the anode and the upper electrode 25 is the cathode, layer 4430-1 functions as a hole injection layer, layer 4430-2 functions as a hole transport layer, layer 4420-1 functions as an electron transport layer, and layer 4420-2 functions as an electron injection layer. Alternatively, when the lower electrode 21 is used as the cathode and the upper electrode 25 as the anode, layer 4430-1 functions as an electron injection layer, layer 4430-2 functions as an electron transport layer, layer 4420-1 functions as a hole transport layer, and layer 4420-2 functions as a hole injection layer. This layer structure allows for efficient injection of carriers into the light-emitting layer 4411 and improves the efficiency of carrier recombination within the light-emitting layer 4411.

[0312] Furthermore, as shown in Figure 16C, a configuration in which multiple light-emitting layers (light-emitting layers 4411, 4412, and 4413) are provided between layer 4420 and layer 4430 is also a variation of the single structure.

[0313] Furthermore, as shown in Figure 16D, a configuration in which multiple light-emitting units (EL layer 23a, EL layer 23b) are connected in series via an intermediate layer (charge generation layer) 4440 is referred to as a tandem structure in this specification. In this specification, the configuration shown in Figure 16D is referred to as a tandem structure, but it is not limited to this, and for example, a tandem structure may also be called a stack structure. By using a tandem structure, a light-emitting element capable of high-brightness light emission can be made.

[0314] In Figure 16D, the same light-emitting material may be used for both the light-emitting layer 4411 and the light-emitting layer 4412. Alternatively, light-emitting materials that emit different types of light may be used for the light-emitting layer 4411 and the light-emitting layer 4412. When the light emitted by the light-emitting layer 4411 and the light emitted by the light-emitting layer 4412 are complementary colors, white light emission is obtained.

[0315] Furthermore, in Figures 16C and 16D, as shown in Figure 16B, layer 4420 and layer 4430 may be a laminated structure consisting of two or more layers.

[0316] Furthermore, a structure in which each light-emitting element produces a different emission color (in this case, blue (B), green (G), and red (R)) is sometimes called an SBS (Side By Side) structure.

[0317] The light-emitting color of the light-emitting element can be red, green, blue, cyan, magenta, yellow, or white, depending on the material constituting the EL layer 23. Furthermore, the color purity can be further enhanced by adding a microcavity structure to the light-emitting element.

[0318] A light-emitting element that emits white light preferably has a configuration that includes two or more types of light-emitting materials in its light-emitting layer. To obtain white light emission, it is sufficient to select light-emitting materials such that the light emitted by each of the two or more materials is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary in color, a light-emitting element that emits white light as a whole can be obtained. The same applies to light-emitting elements that have three or more light-emitting layers.

[0319] The light-emitting layer preferably contains two or more light-emitting materials that emit light such as R (red), G (green), B (blue), Y (yellow), and O (orange). Alternatively, it is preferable to have two or more light-emitting materials, and for each light-emitting material to emit light that contains spectral components of two or more colors from R, G, and B.

[0320] Here, we will describe a specific example of the configuration of a light-emitting element.

[0321] A light-emitting element has at least a light-emitting layer. Furthermore, the light-emitting element may also have layers other than the light-emitting layer, such as a material with high hole injection properties, a material with high hole transport properties, a hole-blocking material, a material with high electron transport properties, an electron-blocking material, a material with high electron injection properties, or a bipolar material (a material with high electron and hole transport properties).

[0322] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0323] For example, a light-emitting device may have a configuration that includes, in addition to the light-emitting layer, one or more layers from among a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0324] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0325] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0326] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds.

[0327] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer containing a material with high electron injection capabilities. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection capabilities. Composite materials containing both electron transport materials and donor materials (electron-donating materials) can also be used as materials with high electron injection capabilities.

[0328] Examples of electron injection layers include lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-(quinolinolato)lithium (abbreviated as Liq), 2-(2-pyridyl)phenolate (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolate (abbreviated as LiPPP), and lithium oxide (LiO2). x ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used.

[0329] Alternatively, an electron-transporting material may be used as the electron injection layer described above. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0330] Furthermore, it is preferable that the lowest unoccupied molecular orbital (LUMO) of an organic compound containing a lone pair of electrons is between -3.6 eV and -2.3 eV. In addition, the highest occupied molecular orbital (HOMO) level and LUMO level of an organic compound can generally be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0331] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0332] The luminescent layer is a layer containing a luminescent material. The luminescent layer may contain one or more types of luminescent materials. Suitable luminescent materials include those exhibiting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Furthermore, materials emitting near-infrared light may also be used as luminescent materials.

[0333] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0334] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0335] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0336] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and / or electron-transporting materials. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0337] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0338] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0339] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0340] (Embodiment 4) This embodiment describes a high-resolution display device.

[0341] [Example of display panel configuration] Wearable electronic devices for VR and AR can provide 3D images by using parallax. In this case, the image for the right eye must be displayed within the right eye's field of view, and the image for the left eye must be displayed within the left eye's field of view. Here, the display area of ​​the display device may be a horizontally elongated rectangle, but pixels located outside the fields of view of the right and left eyes do not contribute to the display, and therefore these pixels will always display black.

[0342] Therefore, it is preferable to divide the display panel into two areas, one for the right eye and one for the left eye, and to configure it so that pixels are not placed in the outer area that does not contribute to the display. This reduces the power consumption required for writing pixels. In addition, the load on source lines, gate lines, etc. is reduced, making it possible to display at a higher frame rate. As a result, smoother video can be displayed, which enhances the sense of realism.

[0343] Figure 17A shows an example of the display panel configuration. In Figure 17A, the left eye display unit 702L and the right eye display unit 702R are arranged inside the circuit board 701. In addition to the display units 702L and 702R, the circuit board 701 may also contain drive circuits, wiring, ICs, FPCs, etc.

[0344] The display units 702L and 702R shown in Figure 17A have a square top surface shape.

[0345] Furthermore, the top shapes of the display units 702L and 702R may be other regular polygons. Figure 17B shows an example of a regular hexagon, Figure 17C shows an example of a regular octagon, Figure 17D shows an example of a regular decagon, and Figure 17E shows an example of a regular dodecagon. In this way, by using a polygon with an even number of corners, the shape of the display unit can be made symmetrical. Note that polygons that are not regular polygons may also be used. In addition, regular polygons or polygons with rounded corners may be used.

[0346] Furthermore, because the display area is composed of pixels arranged in a matrix, the straight sections of the outline of each display area are not strictly straight lines, and there may be stepped sections. In particular, the straight sections that are not parallel to the direction of pixel arrangement will have a stepped top surface shape. However, since the user does not perceive the shape of the pixels when viewing the display, even if the diagonal outline of the display area is strictly stepped, it can be considered a straight line. Similarly, even if the curved sections of the outline of the display area are strictly stepped, they can be considered curves.

[0347] Figure 17F also shows an example where the top surface shape of the display unit 702L and the display unit 702R is a circle.

[0348] Furthermore, the top shapes of the display units 702L and 702R may be asymmetrical. Also, they do not have to be regular polygons.

[0349] Figure 17G shows an example where the top surfaces of the display units 702L and 702R are asymmetrical octagons. Figure 17H ​​shows an example where they are regular heptagons. Even when the top surfaces of the display units 702L and 702R are asymmetrical, it is preferable to arrange the display units 702L and 702R symmetrically. This allows for the provision of images that do not appear unnatural.

[0350] The above describes a configuration where the display unit is divided into two parts, but it may also be a single, continuous shape.

[0351] Figure 17I shows an example of connecting the two circular display units in Figure 17F. Figure 17J shows an example of connecting the two regular octagonal display units in Figure 17C.

[0352] The above is an explanation of an example of a display panel configuration.

[0353] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0354] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0355] (Embodiment 5) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0356] The metal oxide used in the OS transistor preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc. In particular, M is preferably one or more selected from gallium, aluminum, yttrium, and tin, and more preferably gallium.

[0357] Furthermore, metal oxides can be formed by methods such as sputtering, chemical vapor deposition (CVD) methods including metal-organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).

[0358] In the following sections, we will describe oxides containing indium (In), gallium (Ga), and zinc (Zn) as examples of metal oxides. Note that oxides containing indium (In), gallium (Ga), and zinc (Zn) are sometimes called In-Ga-Zn oxides.

[0359] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

[0360] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. For example, it can be evaluated using the XRD spectrum obtained from a GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also known as the thin-film method or the Seemann-Bohlin method. In the following text, the XRD spectrum obtained from a GIXD measurement may simply be referred to as the XRD spectrum.

[0361] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an In-Ga-Zn oxide film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peaks clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0362] Furthermore, the crystalline structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed using nano-beam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. On the other hand, a spot-like pattern is observed in the diffraction pattern of an In-Ga-Zn oxide film deposited at room temperature, rather than a halo. Therefore, it is presumed that an In-Ga-Zn oxide film deposited at room temperature is in an intermediate state, neither single-crystal nor polycrystalline, nor amorphous, and cannot be concluded to be in an amorphous state.

[0363] <<Oxide semiconductor structure>> It should be noted that oxide semiconductors may be classified differently from those described above when considering their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0364] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0365] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0366] Each of the multiple crystalline regions described above is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of a single minute crystal, the maximum diameter of that crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of that crystalline region may be around several tens of nanometers.

[0367] Furthermore, in In-Ga-Zn oxides, CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing gallium (Ga), zinc (Zn), and oxygen (hereinafter referred to as the (Ga,Zn) layer). Note that indium and gallium are mutually substitutable. Therefore, the (Ga,Zn) layer may contain indium. Also, the In layer may contain gallium. Also, the In layer may contain zinc. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0368] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the c-axis orientation peak (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0369] Furthermore, for example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0370] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have lattice arrangements such as pentagons or heptagons. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to factors such as the non-dense arrangement of oxygen atoms in the ab-plane direction and the change in interatomic bond distances due to the substitution of metal atoms.

[0371] A crystal structure in which clear grain boundaries are observed is called a polycrystal. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in transistor on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they suppress the generation of grain boundaries more than In oxide.

[0372] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities and the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0373] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0374] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0375] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0376] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0377] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0378] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0379] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0380] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0381] Furthermore, CAC-OS in In-Ga-Zn oxide refers to a material composition containing In, Ga, Zn, and O, in which regions with Ga as the main component and regions with In as the main component are arranged in a mosaic-like manner, with these regions existing randomly. Therefore, it is presumed that CAC-OS has a structure in which metal elements are unevenly distributed.

[0382] CAC-OS can be formed by sputtering, for example, under conditions where the substrate is not intentionally heated. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. Furthermore, a lower ratio of the oxygen gas flow rate to the total deposition gas flow rate during film formation is preferable. For example, the ratio of the oxygen gas flow rate to the total deposition gas flow rate during film formation should be 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0383] Furthermore, for example, in the case of CAC-OS in In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0384] Here, the first region is a region with higher conductivity compared to the second region. In other words, the conductivity of the metal oxide is exhibited when carriers flow through the first region. Therefore, a high field-effect mobility (μ) can be achieved when the first region is distributed in a cloud-like manner within the metal oxide.

[0385] On the other hand, the second region is a region with higher insulating properties compared to the first region. In other words, the distribution of the second region within the metal oxide can suppress leakage current.

[0386] Therefore, when using CAC-OS in a transistor, the conductivity caused by the first region and the insulating property caused by the second region act complementarily, enabling the function of switching (on / off function) to be imparted to the CAC-OS. That is, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and has a semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be enhanced to the maximum extent. Therefore, by using CAC-OS in a transistor, a high on-current (I on ), high field-effect mobility (μ), and good switching operation can be realized.

[0387] In addition, a transistor using CAC-OS has high reliability. Therefore, CAC-OS is optimal for various semiconductor devices including display devices.

[0388] Oxide semiconductors have various structures and each has different characteristics. The oxide semiconductor according to one aspect of the present invention may have two or more of amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0389] <Transistor having an oxide semiconductor> Subsequently, the case of using the above oxide semiconductor in a transistor will be described.

[0390] By using the above oxide semiconductor in a transistor, a transistor with high field-effect mobility can be realized. In addition, a highly reliable transistor can be realized.

[0391] For a transistor, it is preferable to use an oxide semiconductor with a low carrier concentration. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 or less, preferably 1×10 15 cm -3 or less, more preferably 1×10 13 cm -3More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, when lowering the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film should be lowered to reduce the defect level density. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that oxide semiconductors with low carrier concentrations are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0392] Furthermore, oxide semiconductor films that are highly intrinsic or substantially highly intrinsic may have a low trap level density due to their low defect level density.

[0393] Furthermore, charges trapped in the trap levels of oxide semiconductors can take a long time to disappear, sometimes behaving like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high trap level density may exhibit unstable electrical properties.

[0394] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in stabilizing the electrical characteristics of a transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon. Note that impurities in an oxide semiconductor refer to elements other than the main components that make up the oxide semiconductor. For example, elements with a concentration of less than 0.1 atomic percent can be considered impurities.

[0395] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0396] In oxide semiconductors, the presence of silicon or carbon, which are Group 14 elements, leads to the formation of defect levels in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are compared by 2 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0397] Furthermore, if an oxide semiconductor contains alkali metals or alkaline earth metals, it may form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0398] Furthermore, in oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. As a result, the electrical properties of the transistor may become unstable. For this reason, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻⁶. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0399] Furthermore, hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. Hydrogen can then fill these vacancies, generating electrons as carriers. Additionally, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0400] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0401] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0402] (Embodiment 6) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 18 to 21.

[0403] The electronic device of this embodiment has a display device according to one aspect of the present invention. The display device according to one aspect of the present invention is easily made high-definition, high-resolution, and large-scale. Therefore, the display device according to one aspect of the present invention can be used in the display units of various electronic devices.

[0404] Furthermore, since the display device according to one aspect of the present invention can be manufactured at a low cost, the manufacturing cost of electronic devices can be reduced.

[0405] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as other electronic devices with relatively large screens, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0406] In particular, a display device according to one aspect of the present invention can be used suitably in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include information terminals (wearable devices) such as wristwatches and bracelets, as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays and AR devices such as glasses. Wearable devices also include devices for SR (Substitutional Reality) and devices for MR (Mixed Reality).

[0407] A display device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K2K (3840 x 2160 pixels), or 8K4K (7680 x 4320 pixels). In particular, a resolution of 4K2K, 8K4K, or higher is preferred. Furthermore, the pixel density (resolution) of the display device according to one aspect of the present invention is preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using display devices with such high resolution or high detail, it becomes possible to enhance the sense of presence and depth in personal electronic devices such as portable or home-use devices.

[0408] The electronic device of this embodiment can be incorporated along the curved surfaces of the interior or exterior walls of a house or building, or the interior or exterior of an automobile.

[0409] The electronic device in this embodiment may have an antenna. By receiving signals with the antenna, the display unit can display images and information. Furthermore, if the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0410] The electronic device of this embodiment may have sensors (including those with the function of detecting, detecting, or measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0411] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0412] The electronic device 6500 shown in Figure 18A is a portable information terminal that can be used as a smartphone.

[0413] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0414] A display device according to one aspect of the present invention can be applied to the display unit 6502.

[0415] Figure 18B is a schematic cross-sectional view of the housing 6501, including the end on the microphone 6506 side.

[0416] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, battery 6518, etc. are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0417] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0418] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0419] A flexible display (a display device with flexibility) according to one embodiment of the present invention can be applied to the display panel 6511. As a result, an extremely lightweight electronic device can be realized. Furthermore, because the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel area, an electronic device with a narrow bezel can be realized.

[0420] Figure 19A shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7101. Here, the housing 7101 is shown supported by a stand 7103.

[0421] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0422] The television device 7100 shown in Figure 19A can be operated using the operation switches on the housing 7101 and a separate remote control unit 7111. Alternatively, the display unit 7000 may be equipped with a touch sensor, and the television device 7100 can be operated by touching the display unit 7000 with a finger or the like. The remote control unit 7111 may have a display unit that displays information output from the remote control unit 7111. Channels and volume can be controlled and the image displayed on the display unit 7000 can be controlled using the operation keys or touch panel on the remote control unit 7111.

[0423] The television system 7100 is configured to include a receiver and a modem. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0424] Figure 19B shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0425] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0426] Figures 19C and 19D show examples of digital signage.

[0427] The digital signage 7300 shown in Figure 19C comprises a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switches), connection terminals, various sensors, a microphone, etc.

[0428] Figure 19D shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0429] In Figures 19C and 19D, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0430] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0431] Applying a touch panel to the display unit 7000 is preferable because it not only allows images or videos to be displayed on the display unit 7000, but also enables intuitive operation by the user. Furthermore, when used for purposes such as providing route information or traffic information, intuitive operation can enhance usability.

[0432] Furthermore, as shown in Figures 19C and 19D, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or information terminal 7411. Also, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0433] Furthermore, the digital signage 7300 or digital signage 7400 can be used to run games using the screen of the information terminal 7311 or information terminal 7411 as the control device (controller). This allows a large number of users to participate in and enjoy the game simultaneously.

[0434] Figure 20A shows the external appearance of the camera 8000 with the viewfinder 8100 attached.

[0435] The camera 8000 includes a housing 8001, a display unit 8002, operation buttons 8003, a shutter button 8004, etc. A detachable lens 8006 is also attached to the camera 8000. The lens 8006 and the housing 8001 may be integrated into a single unit.

[0436] Camera 8000 can take an image by pressing the shutter button 8004 or by touching the display unit 8002, which functions as a touch panel.

[0437] The housing 8001 has a mount with electrodes, and in addition to the viewfinder 8100, a strobe device and the like can be connected to it.

[0438] The viewfinder 8100 includes a housing 8101, a display unit 8102, buttons 8103, etc.

[0439] The housing 8101 is attached to the camera 8000 by a mount that engages with the camera 8000's mount. The viewfinder 8100 can display images and other data received from the camera 8000 on the display unit 8102.

[0440] Button 8103 functions as a power button, etc.

[0441] A display device according to one embodiment of the present invention can be applied to the display unit 8002 of the camera 8000 and the display unit 8102 of the viewfinder 8100. The camera 8000 may also have a built-in viewfinder.

[0442] Figure 20B shows the external appearance of the head-mounted display 8200.

[0443] The head-mounted display 8200 includes a mounting section 8201, lenses 8202, a main unit 8203, a display unit 8204, a cable 8205, etc. The mounting section 8201 also has a built-in battery 8206.

[0444] Cable 8205 supplies power from battery 8206 to main unit 8203. Main unit 8203 is equipped with a wireless receiver and can display received video information on display unit 8204. In addition, main unit 8203 is equipped with a camera and can use information about the user's eyeball or eyelid movements as an input means.

[0445] Furthermore, the attachment unit 8201 may be provided with multiple electrodes at a position that touches the user, capable of detecting the current flowing in accordance with the user's eye movements, and may have a function to recognize the user's gaze. It may also have a function to monitor the user's pulse rate based on the current flowing through the electrodes. In addition, the attachment unit 8201 may have various sensors such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may have a function to display the user's biometric information on the display unit 8204, or a function to change the image displayed on the display unit 8204 in accordance with the user's head movements.

[0446] A display device according to one aspect of the present invention can be applied to the display unit 8204.

[0447] Figures 20C to 20E show the external appearance of the head-mounted display 8300. The head-mounted display 8300 includes a housing 8301, a display unit 8302, a band-shaped fixing device 8304, and a pair of lenses 8305.

[0448] The user can view the display on the display unit 8302 through the lens 8305. It is preferable to position the display unit 8302 in a curved shape, as this allows the user to experience a greater sense of presence. Furthermore, by viewing different images displayed in different areas of the display unit 8302 through the lens 8305, three-dimensional display using parallax can be performed. Note that the configuration is not limited to a single display unit 8302; two display units 8302 may be provided, with one display unit for each of the user's eyes.

[0449] A display device according to one embodiment of the present invention can be applied to the display unit 8302. This display device according to one embodiment of the present invention can achieve extremely high resolution. For example, even when the display is magnified and viewed using the lens 8305 as shown in Figure 20E, the pixels are difficult for the user to see. In other words, the display unit 8302 can be used to allow the user to view highly realistic images.

[0450] Figure 20F shows the external appearance of a goggle-type head-mounted display 8400. The head-mounted display 8400 has a pair of housings 8401, a mounting part 8402, and a cushioning member 8403. A display unit 8404 and a lens 8405 are provided inside each of the pair of housings 8401. By displaying different images on the pair of display units 8404, a three-dimensional display using parallax can be achieved.

[0451] The user can view the display unit 8404 through the lens 8405. The lens 8405 has a focusing mechanism, which allows the position of the lens 8405 to be adjusted according to the user's eyesight. The display unit 8404 is preferably a square or a horizontally elongated rectangle. This can enhance the sense of realism.

[0452] The mounting portion 8402 is preferably adjustable to the size of the user's face and has plasticity and elasticity to prevent it from slipping off. Furthermore, it is preferable that a part of the mounting portion 8402 has a vibration mechanism that functions as a bone conduction earphone. This eliminates the need for separate audio equipment such as earphones or speakers, allowing users to enjoy video and audio simply by wearing the device. The housing 8401 may also have a function to output audio data via wireless communication.

[0453] The mounting portion 8402 and the cushioning member 8403 are parts that come into contact with the user's face (forehead, cheeks, etc.). By ensuring that the cushioning member 8403 is in close contact with the user's face, light leakage can be prevented, thereby enhancing the sense of immersion. It is preferable to use a soft material for the cushioning member 8403 so that it adheres closely to the user's face when the user wears the head-mounted display 8400. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, if the surface of a sponge or similar material is covered with cloth, leather (genuine leather or synthetic leather), gaps are less likely to form between the user's face and the cushioning member 8403, effectively preventing light leakage. In addition, using such materials is preferable because it feels good against the skin and does not make the user feel cold when worn in cold seasons. It is preferable that the components that come into contact with the user's skin, such as the cushioning member 8403 or the mounting portion 8402, are removable, as this makes cleaning or replacement easier.

[0454] The electronic equipment shown in Figures 21A to 21F includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, sensors 9007 (including functions for detecting, detecting, or measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 9008, etc.

[0455] The electronic devices shown in Figures 21A to 21F have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them to a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0456] A display device according to one embodiment of the present invention can be applied to the display unit 9001.

[0457] Details of the electronic equipment shown in Figures 21A to 21F will be explained below.

[0458] Figure 21A is a perspective view showing a personal digital assistant (PDA) 9101. The PDA 9101 can be used, for example, as a smartphone. The PDA 9101 may also be equipped with a speaker 9003, connection terminals 9006, sensors 9007, etc. The PDA 9101 can also display text and image information on multiple surfaces. Figure 21A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, and phone calls, the subject of emails and SNS messages, the sender's name, date and time, battery level, and antenna signal strength. Alternatively, icons 9050 or the like may be displayed in the location where the information 9051 is displayed.

[0459] Figure 21B is a perspective view showing the personal digital assistant (PDA) 9102. The PDA 9102 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9102, while the PDA 9102 is stored in the breast pocket of their clothing. The user can check the display without taking the PDA 9102 out of their pocket and decide, for example, whether or not to answer a call.

[0460] Figure 21C is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also be used for hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0461] Figures 21D to 21F are perspective views showing a foldable portable information terminal 9201. Figure 21D shows the portable information terminal 9201 in an unfolded state, Figure 21F shows it in a folded state, and Figure 21E shows a perspective view of the state in between Figures 21D and 21F. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0462] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0463] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part. [Examples]

[0464] In this embodiment, we confirmed the step coverage when an insulating layer was formed to cover the edges of the pixel electrodes, and then an EL layer was formed.

[0465] First, a substrate was prepared on which a pixel circuit, comprising transistors and wiring, and a planarization film covering the pixel circuit were formed on a glass substrate. Next, a conductive layer 111a and a conductive layer 111b were laminated on the planarization film to form a pixel electrode. Subsequently, an insulating layer 131 was formed to cover the edges of the pixel electrode, and insulating layers 132a and 132b were laminated to form an insulating layer 131 and an insulating layer 132 to cover the insulating layer 131. Finally, an EL film 112Rf, a sacrificial film 144, and a sacrificial film 146 were formed.

[0466] For conductive layer 111a, an alloy of silver (Ag), palladium (Pd), and copper (Cu) (Ag-Pd-Cu(APC)) was deposited by sputtering to a thickness of 100 nm. For conductive layer 111b, indium tin oxide (ITSO) containing silicon oxide was formed by sputtering to a thickness of 100 nm.

[0467] As the insulating layer 131, a photosensitive polyimide was formed to a thickness of approximately 1 μm.

[0468] For the insulating layer 132a, a silicon nitride film was formed to a thickness of approximately 50 nm by plasma CVD. For the insulating layer 132b, a silicon oxynitride film was formed to a thickness of approximately 150 nm by plasma CVD.

[0469] For the EL film 112Rf, a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer were formed by vapor deposition to a thickness of approximately 200 nm. For the sacrificial film 144, a metal oxide film was formed by ALD to a thickness of approximately 30 nm. For the sacrificial film 146, a metal oxide film different from sacrificial film 144 was formed by sputtering to a thickness of approximately 50 nm.

[0470] Cross-sectional observation was performed on the substrate after the sacrificial layer 146 had been formed in this manner. Figure 22A shows cross-sectional STEM images of the edges and vicinity of the insulating layer 131, insulating layer 132a, and insulating layer 132b. Figure 22B is a schematic diagram showing the outlines of each layer in Figure 21A.

[0471] As shown in Figure 22A, it was confirmed that the taper angle at the end of insulating layer 132a was different from the taper angle at the end of insulating layer 132b. The taper angle of insulating layer 132a was approximately 90 degrees, and the taper angle of insulating layer 132b was approximately 65 degrees.

[0472] Furthermore, it was confirmed that the EL film 112Rf adequately covered the surfaces of the insulating layer 132a and the insulating layer 132b. In addition, the sacrificial films 144 and 146 on the EL film 112Rf also adequately covered the EL film 112Rf, and no defects were observed.

[0473] The above is a description of the examples. [Explanation of symbols]

[0474] 100, 100A-F: Display device 101: Substrate 110: Light-emitting element 110R, G, B, P, Q: Light-emitting element 111: Pixel electrode 111a, b: Conductive layer 111R, G, B, P, Q: Pixel electrode 111C: Connection electrode 112: EL layer 112R, G, B, P, Q: EL layer 112Rf, Gf, Bf: EL film 113: Common electrode 114: EL layer 115R, G, B: Optical adjustment layer 121: Protective layer 130: Connection part 131, 132a, b: Insulating layer 131f, 132f: Insulating film 133: Space 141, 143a-c: Resist mask 141f: Resist film 144, 144a-c: Sacrificial film 145, 145a-c: Sacrificial layer 146, 146a-c: Sacrificial film 147, 147a-c: Sacrificial layer 151: Photomask 152, 153: Light

Claims

[Claim 1] It comprises a first pixel electrode, a second pixel electrode, a first insulating layer, a second insulating layer, a first EL layer, a second EL layer, and a common electrode. The first pixel electrode and the second pixel electrode are provided side by side. The first insulating layer covers the ends of the first pixel electrode and the ends of the second pixel electrode. Of the edges of the first insulating layer, a portion overlaps with the upper surface of the first pixel electrode, and another portion overlaps with the upper surface of the second pixel electrode. The second insulating layer is provided on the first pixel electrode, the second pixel electrode, and the first insulating layer, and covers the edge of the first insulating layer. Of the edges of the second insulating layer, a portion overlaps with the upper surface of the first pixel electrode, and another portion overlaps with the upper surface of the second pixel electrode. The first EL layer is provided on the first pixel electrode, The second EL layer is provided on the second pixel electrode, The ends of the first EL layer and the ends of the second EL layer face each other and overlap with the first insulating layer. The common electrode has a portion that overlaps with the first EL layer and a portion that overlaps with the second EL layer. The first insulating layer comprises an organic resin, The display device comprises an inorganic insulating material as the second insulating layer.

Images