Indication device

Abstract

Provided are a high-resolution display device and a method for manufacturing same. The display device has: a first insulation layer; a light-emitting element and a first conductive layer on the first insulation layer; a first layer on the first conductive layer; a second conductive layer on the first layer; a second insulation layer on the light-emitting element, the second conductive layer, and the first insulation layer; and a third conductive layer on the second insulation layer. The light-emitting element has: a fourth conductive layer; a second layer on the fourth conductive layer; a third layer on the second layer; and a fifth conductive layer on the third layer. The third conductive layer has a region contacting the second conductive layer through a first opening provided in the second insulation layer, and a region contacting the fifth conductive layer through a second opening provided in the second insulation layer. The second layer includes a light-emitting compound. The first conductive layer and the fourth conductive layer include the same material, the first layer and the third layer include the same material, and the second conductive layer and the fifth conductive layer include the same material.

Description

[Technical Field]

[0001] 1. Field of the Invention One embodiment of the present invention relates to a display device and a manufacturing method of the display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, driving methods thereof, and manufacturing methods thereof. Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. [Background technology]

[0003] In recent years, there has been a demand for higher resolution display panels. Devices requiring high-resolution display panels, such as devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), have been actively developed in recent years.

[0004] Representative examples of display devices that can be applied to display panels include liquid crystal display devices, organic EL (Electro Luminescence) elements, light-emitting devices equipped with light-emitting elements such as light-emitting diodes (LEDs: Light Emitting Diodes), and electronic paper that displays using electrophoresis methods.

[0005] For example, the basic structure of an organic EL element is a layer containing a light-emitting organic compound sandwiched between a pair of electrodes. By applying a voltage to this element, light can be emitted from the light-emitting organic compound. A display device using such an organic EL element does not require a backlight, which is necessary in liquid crystal display devices and the like, and therefore can realize a thin, lightweight, high-contrast, and low-power display device. For example, an example of a display device using an organic EL element is described in Patent Document 1. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-324673 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, in the wearable devices for VR, AR, SR, or MR described above, a focus adjustment lens must be provided between the eyes and the display panel. Because the lens magnifies part of the screen, if the resolution of the display panel is low, this can cause a problem of diminishing the sense of realism and immersion.

[0008] Furthermore, display panels are required to have high color reproducibility. In particular, in the above-mentioned devices for VR, AR, SR, or MR, by using a display panel with high color reproducibility, it is possible to display colors that are close to the colors of real objects, thereby enhancing the sense of realism and immersion.

[0009] An object of one embodiment of the present invention is to provide a display device with extremely high resolution.An object of one embodiment of the present invention is to provide a display device with high color reproducibility.An object of one embodiment of the present invention is to provide a display device with high luminance.An object of one embodiment of the present invention is to provide a display device with high reliability.Another object of one embodiment of the present invention is to provide a method for manufacturing the above-described display device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0011] One embodiment of the present invention is a display device including a first insulating layer, a light-emitting element and a first conductive layer on the first insulating layer, a first layer on the first conductive layer, a second conductive layer on the first layer, and a third conductive layer on the light-emitting element and the second conductive layer. The light-emitting element includes a fourth conductive layer, a second layer on the fourth conductive layer, a third layer on the second layer, and a fifth conductive layer on the third layer. The third conductive layer has a region in contact with the second conductive layer and a region in contact with the fifth conductive layer. The second layer includes a light-emitting compound. The first conductive layer and the fourth conductive layer include the same material. The first layer and the third layer include the same material. The second conductive layer and the fifth conductive layer include the same material.

[0012] Another embodiment of the present invention is a display device including a first insulating layer, a light-emitting element and a first conductive layer over the first insulating layer, a first layer over the first conductive layer, a second conductive layer over the first layer, a second insulating layer over the light-emitting element, the second conductive layer, and the first insulating layer, and a third conductive layer over the second insulating layer. The light-emitting element has a fourth conductive layer, a second layer on the fourth conductive layer, a third layer on the second layer, and a fifth conductive layer on the third layer, the second insulating layer having regions in contact with each of a side surface of the fourth conductive layer, a side surface of the second layer, a side surface of the third layer, a side surface of the fifth conductive layer, and a top surface of the fifth conductive layer, the second insulating layer having a first opening having a region overlapping with the second conductive layer and a second opening having a region overlapping with the fifth conductive layer, the third conductive layer having a region in contact with the second conductive layer through the first opening and a region in contact with the fifth conductive layer through the second opening, the second layer containing a light-emitting compound, the first conductive layer and the fourth conductive layer containing the same material, the first layer and the third layer containing the same material, and the second conductive layer and the fifth conductive layer containing the same material.

[0013] In the above display device, it is preferable that the second insulating layer has a laminated structure of a third insulating layer and a fourth insulating layer on the third insulating layer, and the third insulating layer has a region in contact with a side surface of the fourth conductive layer, a region in contact with a side surface of the second layer, a region in contact with a side surface of the third layer, a region in contact with a side surface of the fifth conductive layer, and a region in contact with a top surface of the fifth conductive layer, and that the third insulating layer contains aluminum and oxygen, and the fourth insulating layer contains silicon and nitrogen.

[0014] In the display device, it is preferable that a gap be formed between the third insulating layer and the fourth insulating layer in a region that does not overlap with the fifth conductive layer.

[0015] In the display device, the third layer preferably contains a substance with a high electron injecting property and lithium fluoride.

[0016] Alternatively, in the above display device, the third layer preferably contains a compound having an electron-deficient heteroaromatic ring and silver.

[0017] Another embodiment of the present invention is a method for forming a first conductive film on a first insulating layer, forming a first film containing a light-emitting compound on the first conductive film, forming a first sacrificial layer on the first film, forming a first resist mask on the first sacrificial layer, and removing the first sacrificial layer and the first film that are not covered with the first resist mask to form a second sacrificial layer from the first sacrificial layer, forming a second film from the first film, removing the second sacrificial layer, forming a third film on the second film, and forming a third film. A method for manufacturing a display device includes forming a second conductive film over a film, forming a second resist mask over the second conductive film, and removing the second conductive film, the third film, the second film, and the first conductive film that are not covered with the second resist mask, thereby forming a fifth conductive layer and a second conductive layer from the second conductive film, forming the third layer and the first layer from the third film, forming the second layer from the second film, and forming a fourth conductive layer and the first conductive layer from the first conductive film.

[0018] Another embodiment of the present invention is a method for forming a first conductive film over a first insulating layer, forming a first film containing a light-emitting compound over the first conductive film, forming a first sacrificial layer over the first film, forming a first resist mask over the first sacrificial layer, and removing the first sacrificial layer and the first film that are not covered with the first resist mask to form a second sacrificial layer from the first sacrificial layer, forming a second film from the first film, removing the second sacrificial layer, forming a third film over the second film using a metal mask, and forming a third film. a second conductive film is formed on the first conductive film and the second conductive film; a second resist mask is formed on the second conductive film; and the second conductive film, the third film, the second film, and the first conductive film that are not covered with the second resist mask are removed to form a fifth conductive layer and a second conductive layer from the second conductive film, form a third layer from the third film, form a second layer from the second film, and form a fourth conductive layer and a first conductive layer in contact with the second conductive layer from the first conductive film.

[0019] In the above-mentioned method for manufacturing a display device, it is preferable that after forming the fifth conductive layer and the second conductive layer, the third layer and the first layer, the second layer, and the fourth conductive layer and the first conductive layer, a second insulating layer is formed on the second conductive layer, the fifth conductive layer, and the first insulating layer, a first opening is formed in the second insulating layer in a region overlapping with the second conductive layer, and a second opening is formed in the second insulating layer in a region overlapping with the fifth conductive layer, and a third conductive layer is formed so as to be in contact with the second conductive layer through the first opening and in contact with the fifth conductive layer through the second opening.

[0020] In the above-mentioned method for manufacturing a display device, it is preferable that the second insulating layer has a laminated structure of a third insulating layer and a fourth insulating layer on the third insulating layer, the third insulating layer is formed by an ALD method, and the fourth insulating layer is formed by a sputtering method.

[0021] Furthermore, in the above-mentioned method for manufacturing a display device, it is preferable that the second insulating layer has a laminated structure of a third insulating layer, a fourth insulating layer on the third insulating layer, and a fifth insulating layer on the fourth insulating layer, and that the third insulating layer and the fifth insulating layer are deposited by an ALD method, and that the fourth insulating layer is deposited by a sputtering method.

[0022] In the above-described method for manufacturing a display device, the third film preferably contains a substance having a high electron injection property and lithium fluoride.

[0023] Alternatively, in the above-described method for manufacturing a display device, the third film preferably contains a compound having an electron-deficient heteroaromatic ring and silver. [Effects of the Invention]

[0024] According to one aspect of the present invention, it is possible to provide a display device with extremely high resolution, a display device with high color reproducibility, a display device with high brightness, a display device with high reliability, or a method for manufacturing the display device.

[0025] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0026] 1A to 1C are diagrams showing configuration examples of a display device. 2A to 2C are diagrams showing configuration examples of a display device. 3A to 3D are diagrams showing configuration examples of a display device. 4A1 to 4C2 are diagrams illustrating an example of a method for manufacturing a display device. 5A1 to 5D2 are diagrams illustrating an example of a method for manufacturing a display device. 6A1 to 6C2 are diagrams illustrating an example of a method for manufacturing a display device. 7A1 to 7D2 are diagrams illustrating an example of a method for manufacturing a display device. 8A1 to 8B2 are diagrams illustrating an example of a method for manufacturing a display device. 9A1 to 9C2 are diagrams illustrating an example of a method for manufacturing a display device. FIG. 10 is a diagram showing an example of the configuration of a display device. FIG. 11 is a diagram illustrating an example of the configuration of a display device. FIG. 12 is a diagram illustrating an example of the configuration of a display device. FIG. 13 is a diagram illustrating an example of the configuration of a display device. 14A and 14B are diagrams showing configuration examples of a display module. 15A and 15B are circuit diagrams showing an example of a display device. Figures 16A and 16C are circuit diagrams showing an example of a display device, and Figure 16B is a timing chart showing an example of the operation of the display device. 17A and 17B are diagrams showing configuration examples of electronic devices. 18A and 18B are diagrams showing configuration examples of electronic devices. 19A to 19F are diagrams showing an example of an electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

[0028] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0029] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0030] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0031] Furthermore, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" and "insulating layer" may be interchangeable with the terms "conductive film" and "insulating film."

[0032] In this specification, the EL layer refers to a layer provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance (also referred to as a light-emitting layer), or a stack including a light-emitting layer.

[0033] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting) images etc. on a display surface, and therefore the display panel is one aspect of an output device.

[0034] In addition, in this specification, a display panel having a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) attached to the substrate, or having an IC mounted on the substrate using a COG (Chip On Glass) method or the like, may be referred to as a display panel module, display module, or simply a display panel.

[0035] In addition, in this specification, when upper and lower limit values ​​are specified, it is also considered that a configuration in which the upper limit values ​​and the lower limit values ​​are freely combined is also disclosed.

[0036] (Embodiment 1) In this embodiment, a structural example of a display device according to one embodiment of the present invention and an example of a manufacturing method of the display device will be described.

[0037] A display device according to one embodiment of the present invention includes light-emitting elements (also referred to as light-emitting devices) that emit light of different colors. The light-emitting elements include a lower electrode, an upper electrode, and a layer containing a light-emitting compound (also referred to as a light-emitting layer or an EL layer) between them. As the light-emitting elements, electroluminescent elements such as organic EL elements and inorganic EL elements are preferably used. Alternatively, light-emitting diodes (LEDs) may be used.

[0038] The EL element can be an organic light-emitting diode (OLED) or a quantum-dot light-emitting diode (QLED). Examples of light-emitting materials that EL elements have include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (TADF) materials.

[0039] 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.

[0040] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0041] The light-emitting layer may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). One or more organic compounds may be a hole-transporting material or an electron-transporting material, or both. Alternatively, a bipolar material or a TADF material may be used as the one or more organic compounds.

[0042] The light-emitting layer preferably contains, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triplet Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth, allowing for efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting device.

[0043] As the light-emitting substance, a substance that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, etc. may be appropriately used. A substance that emits near-infrared light may also be used.

[0044] The light-emitting layer may contain one or more compounds (host material, assist material) in addition to the light-emitting substance (guest material). As the host material and the assist material, one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) can be selected and used. As the host material and the assist material, it is preferable to use a combination of compounds that form an exciplex. In order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole-transporting material) with a compound that easily accepts electrons (electron-transporting material).

[0045] The light-emitting element can be made of either a low molecular weight compound or a high molecular weight compound, and may contain an inorganic compound (such as a quantum dot material).

[0046] A display device according to one embodiment of the present invention can produce light-emitting elements of different colors with extremely high precision. Therefore, a display device with higher resolution than conventional display devices can be realized. For example, a highly precise display device is preferred in which pixels each having one or more light-emitting elements are arranged at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and at a resolution of 20000 ppi or less, or 30000 ppi or less.

[0047] Below, a more specific example of a structure and an example of a manufacturing method of a display device of one embodiment of the present invention will be described with reference to the drawings.

[0048] [Configuration example 1] [Configuration Example 1-1] 1A to 1C are diagrams illustrating a display device according to one embodiment of the present invention. FIG. 1A is a schematic top view of a display device 100, and FIGS. 1B and 1C are schematic cross-sectional views of the display device 100. FIG. 1B is a cross-sectional view of a portion indicated by a dashed line X1-X2 in FIG. 1A. FIG. 1C is a cross-sectional view of a portion indicated by a dashed line Y1-Y2 in FIG. 1A. Note that some elements are omitted from the top view of FIG. 1A for clarity.

[0049] When the light emitting elements are arranged in a stripe pattern as shown in FIG. 1A, adjacent light emitting elements of different colors are arranged in the X1-X2 direction, and adjacent light emitting elements of the same color are arranged in the Y1-Y2 direction.

[0050] The display device 100 has an insulating layer 121, a light-emitting element 120R, a light-emitting element 120G, and a light-emitting element 120B. The light-emitting element 120R is a light-emitting element that exhibits red, the light-emitting element 120G is a light-emitting element that exhibits green, and the light-emitting element 120B is a light-emitting element that exhibits blue. In other words, the light-emitting element 120R and the light-emitting element 120G exhibit light of different colors. Furthermore, the light-emitting element 120G and the light-emitting element 120B exhibit light of different colors. Furthermore, the light-emitting element 120B and the light-emitting element 120R exhibit light of different colors. A structure in which each light-emitting element is painted with a different emission color (here, red (R), green (G), and blue (B)) is sometimes called an SBS (Side By Side) structure.

[0051] In this specification, a structure in which different light-emitting layers are fabricated or differently painted for each color light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS structure. In this specification, a light-emitting device that can emit 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.

[0052] In the following, when describing matters common to the light-emitting element 120R, the light-emitting element 120G, and the light-emitting element 120B, the symbols added to the reference numerals may be omitted and the light-emitting element may be referred to as the light-emitting element 120. Similarly, the conductive layer 111R, the conductive layer 111G, and the conductive layer 111B described below may also be referred to as the conductive layer 111. Similarly, the EL layer 115R, the EL layer 115G, and the EL layer 115B described below may also be referred to as the EL layer 115. Similarly, the conductive layer 116R, the conductive layer 116G, and the conductive layer 116B described below may also be referred to as the conductive layer 116. The conductive layer 111R, the EL layer 115R, and the conductive layer 116R are included in the light-emitting element 120R. Similarly, conductive layer 111G, EL layer 115G, and conductive layer 116G are included in light emitting element 120G, and conductive layer 111B, EL layer 115B, and conductive layer 116B are included in light emitting element 120B.

[0053] Furthermore, the combination of colors of light emitted by the light emitting element 120 is not limited to the above, and colors such as cyan, magenta, yellow, etc. may also be used. Furthermore, although the above example shows three colors of red (R), green (G), and blue (B), the number of colors of light emitted by the light emitting element 120 included in the display device 100 may be two colors, or four or more colors.

[0054] The light-emitting element 120 includes a conductive layer 111 functioning as a lower electrode, an EL layer 115, and a conductive layer 116 functioning as an upper electrode. The conductive layer 116 is transparent to and reflective of visible light. The EL layer 115 contains a light-emitting compound.

[0055] The light-emitting element 120 can be an electroluminescent element that emits light in response to a current flowing through the EL layer 115 when a potential difference is applied between the conductive layer 111 and the conductive layer 116. In particular, it is preferable to use an organic EL element that uses a light-emitting organic compound for the EL layer 115. Furthermore, it is preferable that the light-emitting element 120 is an element that emits monochromatic light whose emission spectrum has one peak in the visible light region. Note that the light-emitting element 120 may also be an element that emits white light whose emission spectrum has two or more peaks in the visible light region.

[0056] A potential is independently applied to the conductive layer 111 provided in each light emitting element 120 to control the amount of light emitted by the light emitting element 120. The conductive layer 111 functions as, for example, a pixel electrode.

[0057] The EL layer 115 has at least a layer containing a light-emitting compound. Alternatively, the EL layer 115 may have a laminated structure of one or more layers selected from an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, and a hole injection layer. The EL layer 115 can be formed by a liquid phase method such as a vapor deposition method or an inkjet method.

[0058] The conductive layer 116 is formed to be transmissive and reflective to visible light. For example, a metal film or alloy film thin enough to transmit visible light can be used. Alternatively, a light-transmitting conductive film (for example, a metal oxide film) may be stacked on such a film.

[0059] In the display device 100, the EL layer 115 and the conductive layer 116 are separated between adjacent light-emitting elements of different colors. This prevents current (also called leakage current) from flowing through the EL layer 115 between adjacent light-emitting elements of different colors. This suppresses light emission caused by the leakage current, enabling a high-contrast display. Furthermore, even when the resolution is increased, a highly conductive material can be used for the EL layer 115, thereby broadening the range of material options and facilitating improved efficiency, reduced power consumption, and improved reliability.

[0060] The EL layer 115 and the conductive layer 116 may be formed into island patterns by film formation using a shadow mask such as a metal mask, but it is preferable to use a processing method that does not use a metal mask. This makes it possible to form extremely fine patterns, thereby improving the definition and aperture ratio compared to formation methods that use metal masks. A typical processing method that can be used is photolithography. Other formation methods that can be used include nanoimprinting and sandblasting.

[0061] In this specification, etc., a device fabricated using a metal mask or FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification, etc., a device fabricated without using a metal mask or FMM may be referred to as a device with an MML (metal maskless) structure.

[0062] From the above, it is possible to realize an extremely high-definition display device in which pixels having one or more light-emitting elements are arranged at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20,000 ppi or less, or 30,000 ppi or less.

[0063] The display device 100 has a configuration in which the side surfaces of the conductive layer 111, the EL layer 115, and the conductive layer 116 are generally aligned.

[0064] In this specification, "side surfaces that approximately match" refers to the overlapping of at least a portion of the contours of the upper and lower layers when viewed from above. For example, this includes cases where the upper and lower layers are processed using the same mask pattern or a portion of the same mask pattern. "side surfaces that approximately match" also includes cases where the side surfaces match. However, strictly speaking, the contours may not overlap, and the contour of the upper layer may be located inside the contour of the lower layer, or the contour of the upper layer may be located outside the contour of the lower layer. In these cases, the term "side surfaces that approximately match" is also used.

[0065] The insulating layer 121 has a single layer or a stacked structure of two or more layers. For example, when the insulating layer 121 has a stacked structure of two layers, it is preferable to select an insulator that functions as an etching stopper film when the conductive film that will become the conductive layer 111 is etched to form the conductive layer 111, for the layer on the conductive layer 111 side. For example, when silicon oxide or silicon oxynitride is used for the layer on the substrate 101 side, it is preferable to use silicon nitride, aluminum oxide, hafnium oxide, or the like for the layer on the conductive layer 111 side.

[0066] The display device 100 includes a structure 132 .

[0067] The structure 132 functions as a wiring. Alternatively, the structure 132 functions as a plug that electrically connects the conductive layer 139 and a wiring (not shown) located below the structure 132. The structure 132 has a conductive layer 133 on the insulating layer 121, a layer 134 on the conductive layer 133, and a conductive layer 135 on the layer 134. The structure 132 has a configuration in which the side surfaces of the conductive layer 133, the layer 134, and the conductive layer 135 are generally aligned.

[0068] The conductive layer 133 and the conductive layer 111 contain the same material. The conductive layer 135 and the conductive layer 116 contain the same material. The layer 134 contains the same material as the EL layer 115.

[0069] The structure 132 must be conductive to function as a wiring or a plug. On the other hand, the layer 134 has a band gap because it contains the material contained in the EL layer 115. Therefore, it is preferable that the film thickness of the layer 134 is thin. The film thickness of the layer 134 is preferably 0.5 nm or more and 10 nm or less, and more preferably 1 nm or more and 5 nm or less. With this configuration, the conductive layer 133 and the conductive layer 135 are electrically connected to each other by the tunnel effect or dielectric breakdown. Therefore, the structure 132 can be conductive.

[0070] The display device 100 includes an insulating layer 117 , an insulating layer 118 on the insulating layer 117 , and a conductive layer 139 .

[0071] The insulating layer 117 and the insulating layer 118 are provided with a first opening located in a region overlapping with the conductive layer 135 and a second opening located in a region overlapping with the conductive layer 116 .

[0072] Insulating layer 117 contacts each of a portion of the upper surface of insulating layer 121, the side surface of light-emitting element 120, and a portion of the upper surface of light-emitting element 120. In other words, insulating layer 117 contacts each of a portion of the upper surface of insulating layer 121, the side surface of conductive layer 111, the side surface of EL layer 115, the side surface of conductive layer 116, and a portion of the upper surface of conductive layer 116. In addition, insulating layer 117 contacts each of the side surface of structure 132 and a portion of the upper surface of structure 132. In other words, insulating layer 117 contacts each of the side surface of conductive layer 133, the side surface of layer 134, the side surface of conductive layer 135, and a portion of the upper surface of conductive layer 135.

[0073] An inorganic material is preferably used for the insulating layer 117. Examples of such an inorganic material include an inorganic oxide, an inorganic nitride, and an inorganic oxynitride. A film containing such a material can be used as a single layer or a stacked layer. For example, an aluminum oxide film, a silicon oxide film, or a silicon nitride film can be used for the insulating layer 117. This can suppress the diffusion of impurities such as water.

[0074] Furthermore, it is preferable that the insulating layer 117 be a film formed by an atomic layer deposition (ALD) method or the like.

[0075] The ALD method utilizes the self-regulating property of atoms to deposit atoms layer by layer, and therefore has the advantages of being able to form extremely thin films, be able to form films on structures with high aspect ratios, be able to form films with few defects such as pinholes, be able to form films with excellent coverage, be able to form films at low temperatures, etc. Therefore, insulating layer 117 can be formed with good coverage on the side surfaces of conductive layer 116, EL layer 115, conductive layer 111, etc.

[0076] For the above reasons, an aluminum oxide film formed by an ALD method can be suitably used as the insulating layer 117.

[0077] For example, the insulating layer 118 is preferably made of an inorganic material, an organic material, or a composite material of an inorganic material and an organic material, and more preferably made of an inorganic material. Examples of the inorganic material include inorganic oxides, inorganic nitrides, and inorganic oxynitrides. A film containing any of these materials can be used as a single layer or a stacked layer. For example, the insulating layer 118 can be made of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxide film, an indium gallium zinc oxide film (also referred to as an IGZO film), or the like. These films can be used as a single layer or a stacked layer. Note that a silicon nitride film is a dense film and has an excellent function of suppressing the diffusion of impurities such as water, and therefore can be suitably used as the insulating layer 118.

[0078] Alternatively, the insulating layer 118 may include, for example, polyester, polyolefin, polyamide, polyimide, polycarbonate, polysiloxane, or acrylic resin. Alternatively, the insulating layer 118 may have a laminated structure of the above-mentioned materials. Alternatively, the insulating layer 118 may be a composite material of the above-mentioned materials.

[0079] Alternatively, the insulating layer 118 may be made of an organic material such as a reaction-curing adhesive, a photo-curing adhesive, a thermosetting adhesive, and / or an anaerobic adhesive.

[0080] Note that although the display device 100 has a structure in which the insulating layer 117 and the insulating layer 118 are provided, one embodiment of the present invention is not limited to this. For example, a structure in which the insulating layer 117 is provided but the insulating layer 118 is not provided may be used. Alternatively, a structure in which the insulating layer 117 is not provided but the insulating layer 118 is provided may be used. Alternatively, one or both of the insulating layer 117 and the insulating layer 118 may have a stacked structure.

[0081] The conductive layer 139 has a region in contact with the conductive layer 135 through a first opening provided in the insulating layer 117 and the insulating layer 118, and a region in contact with the conductive layer 116 through a second opening provided in the insulating layer 117 and the insulating layer 118. With this structure, the conductive layer 116 and the conductive layer 135 can be electrically connected to each other.

[0082] The conductive layer 139 can be formed using a conductive film that can be used for the conductive layer 111, the conductive layer 116, and the like.

[0083] With the above configuration, the EL layer of the light-emitting element 120 can be made different for each light-emitting element of a different color, enabling color display with high color reproducibility and low power consumption. Furthermore, by adjusting the film thickness of the EL layer of the light-emitting element 120 to match the peak wavelength of the emission spectrum, a microcavity structure (a microresonator structure) can be imparted, enabling a high-brightness display device to be realized. Furthermore, it becomes possible to arrange the light-emitting elements 120 at an extremely high density. For example, a display device with a resolution exceeding 2000 ppi can be realized.

[0084] The light emitting elements 120 are preferably arranged in a stripe pattern, but may be arranged in a pattern other than a stripe pattern, such as a delta pattern or a mosaic pattern.

[0085] The display device 100 includes the insulating layer 121, the light emitting element 120R, the light emitting element 120G, and the light emitting element 120B, which are provided on a substrate 101 that includes a semiconductor circuit.

[0086] The substrate 101 can be a circuit substrate having transistors, wiring, or the like. When a passive matrix system or a segment system is applicable, an insulating substrate such as a glass substrate can be used as the substrate 101. The substrate 101 is provided with a circuit for driving each light-emitting element (also referred to as a pixel circuit) or a semiconductor circuit that functions as a driver circuit for driving the pixel circuit. A more specific example of the configuration of the substrate 101 will be described later.

[0087] The substrate 101 and the conductive layer 111 of the light emitting element 120 are electrically connected via a plug 131. The plug 131 is formed so as to be embedded in an opening provided in the insulating layer 121. The conductive layer 111 is provided in contact with the upper surface of the plug 131.

[0088] [Configuration Example 1-2] Display device 100 may have an air gap between insulating layer 117 and insulating layer 118. Figure 2A is a schematic cross-sectional view of display device 100 having air gap 137 between insulating layer 117 and insulating layer 118.

[0089] As shown in FIG. 2A, the void 137 is located between the insulating layer 117 and the insulating layer 118 in a region that does not overlap with the conductive layer 116.

[0090] The voids 137 contain, for example, one or more selected from air, nitrogen, oxygen, carbon dioxide, and a Group 18 element. The voids 137 may also contain, for example, a gas used in forming the insulating film that will become the insulating layer 118. For example, when the insulating film that will become the insulating layer 118 is formed by sputtering, the voids 137 may contain a Group 18 element (typically, helium, neon, argon, xenon, krypton, etc.). When the voids 137 contain a gas, the gas can be identified by gas chromatography or the like. When the insulating film that will become the insulating layer 118 is formed by sputtering, the gas used during sputtering may also be contained in the insulating layer 118. In this case, elements such as argon may be detected when the insulating layer 118 is analyzed by energy dispersive X-ray analysis (EDX analysis) or the like.

[0091] When the refractive index of void 137 is lower than the refractive index of EL layer 115, light emitted by EL layer 115 and incident on the interface between EL layer 115 and void 137 is totally reflected. This prevents the light from entering adjacent light-emitting elements. Specifically, light emitted by EL layer 115R can be prevented from entering light-emitting element 120G or light-emitting element 120B. Furthermore, light emitted by EL layer 115G can be prevented from entering light-emitting element 120R or light-emitting element 120B. Furthermore, light emitted by EL layer 115B can be prevented from entering light-emitting element 120R or light-emitting element 120G. This prevents light of different colors from mixing, allowing display device 100 to display high-quality images.

[0092] [Configuration Example 1-3] Insulating layer 118 may have a stacked structure of insulating layer 118a and insulating layer 118b. Figure 2B is a schematic cross-sectional view of display device 100 in which insulating layer 118 has a stacked structure of insulating layer 118a and insulating layer 118b.

[0093] The insulating layer 118 includes an insulating layer 118a on the insulating layer 117 and an insulating layer 118b on the insulating layer 118a.

[0094] The insulating layer 118a and the insulating layer 118b are different in material and / or deposition method. For example, it is preferable to use a silicon nitride film deposited by a sputtering method as the insulating layer 118a and a silicon nitride film deposited by a PEALD method as the insulating layer 118b. In this way, if a pinhole or a step is formed in the film deposited by the sputtering method, the portion overlapping the pinhole or the step can be blocked by using the film deposited by the ALD method, which has good coverage.

[0095] The insulating layer 118 may be formed by stacking three or more layers of films made of different materials and / or formed by different film-forming methods.

[0096] Furthermore, as shown in FIG. 2B, insulating layer 121 may have a recess in a region that does not overlap with conductive layer 111.

[0097] [Configuration Example 1-4] Structure 132 may not have layer 134. Figure 2C is a schematic cross-sectional view of display device 100 having structure 132 made up of conductive layer 133 and conductive layer 135.

[0098] The structure 132 includes a conductive layer 133 on the insulating layer 121 and a conductive layer 135 on the conductive layer 133. With this structure, the structure 132 can have conductivity regardless of the material used for the EL layer 115. Therefore, the structure 132 can function as a wiring or a plug.

[0099] [About the components] [Light-emitting element] The light-emitting element that can be used for the light-emitting element 120 can be a self-luminous element, and includes elements whose brightness is controlled by current or voltage. For example, an LED, an organic EL element, an inorganic EL element, etc. can be used. In particular, it is preferable to use an organic EL element.

[0100] Light-emitting elements are classified into top-emission type, bottom-emission type, dual-emission type, etc. A conductive film that transmits visible light is used for the electrode on the side from which light is extracted, and a conductive film that reflects visible light is used for the electrode on the side from which light is not extracted.

[0101] In one embodiment of the present invention, a top-emission or dual-emission light-emitting element that emits light toward the opposite side to the surface where the light is formed can be preferably used.

[0102] The EL layer 115 includes at least a light-emitting layer. The EL layer 115 may further include a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, a substance with high electron-injection properties, an electron-blocking material, or a bipolar substance (a substance with high electron-transport properties and high hole-transport properties), as a layer other than the light-emitting layer.

[0103] Both low molecular weight compounds and high molecular weight compounds, and inorganic compounds may be used for the EL layer 115. The layers constituting the EL layer 115 can be formed by a deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like.

[0104] When a voltage higher than the threshold voltage of the light-emitting element 120 is applied between the cathode and anode, holes are injected from the anode side and electrons are injected from the cathode side into the EL layer 115. The injected electrons and holes recombine in the EL layer 115, causing the luminescent material contained in the EL layer 115 to emit light.

[0105] When a white-emitting light-emitting element is used as the light-emitting element 120, it is preferable that the EL layer 115 contains two or more types of light-emitting materials. For example, white light can be obtained by selecting light-emitting materials such that the light emitted from the two or more light-emitting materials has a complementary color relationship. For example, it is preferable to include two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), etc., or light-emitting materials that emit light containing spectral components of two or more colors of R, G, and B. It is also preferable to use a light-emitting element whose emission spectrum has two or more peaks in the wavelength range of the visible light region (e.g., 350 nm to 750 nm). It is also preferable that the emission spectrum of a material that has a peak in the yellow wavelength region also contains spectral components in the green and red wavelength regions.

[0106] The EL layer 115 preferably has a configuration in which an emitting layer containing an emitting material that emits one color and an emitting layer containing an emitting material that emits another color are stacked. For example, the multiple emitting layers in the EL layer 115 may be stacked in contact with each other, or may be stacked via a region that does not contain any emitting material. For example, a configuration may be adopted in which, between the fluorescent emitting layer and the phosphorescent emitting layer, there is provided a region that contains the same material (e.g., host material, assist material) as the fluorescent emitting layer or the phosphorescent emitting layer, but does not contain any emitting material. This facilitates fabrication of the light-emitting element and reduces the driving voltage.

[0107] Furthermore, the light-emitting element 120 may be a single element (also called a single-structure device) having one EL layer, or may be a tandem element (also called a tandem-structure device) in which multiple EL layers are stacked with a charge-generating layer interposed therebetween.

[0108] A single-structure device preferably has one light-emitting unit between a pair of electrodes, and the light-emitting unit includes one or more light-emitting layers. To obtain white light emission, two or more light-emitting layers may be selected so that the light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the color of the light emitted from the first light-emitting layer and the color of the light emitted from the second light-emitting layer complementary to each other, a configuration in which the entire light-emitting device emits white light can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0109] A tandem-structured 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. To obtain white light, light from the light-emitting layers of the multiple light-emitting units may be combined to obtain white light. The configuration for obtaining white light is the same as that of the single-structured device. In a tandem-structured device, it is preferable to provide an intermediate layer such as a charge-generating layer between the multiple light-emitting units.

[0110] Furthermore, when comparing the above-mentioned white light-emitting device (single structure or tandem structure) with a light-emitting device having an SBS structure, the light-emitting device having an SBS structure can reduce power consumption compared to the white light-emitting device. If you want to keep power consumption low, it is preferable to use a light-emitting device having an SBS structure. On the other hand, the manufacturing process of a white light-emitting device is simpler than that of a light-emitting device having an SBS structure, so it is preferable because it can reduce manufacturing costs or increase manufacturing yields.

[0111] A conductive film that transmits visible light and can be used for the conductive layer 111 or the like can be formed using, for example, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide doped with gallium, or the like. Metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, alloys containing these metal materials, or nitrides of these metal materials (e.g., titanium nitride), can also be used by forming them thin enough to have light-transmitting properties. A stacked film of any of the above materials can also be used for the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferably used because it can increase conductivity. Graphene or the like may also be used.

[0112] The conductive layer 111 preferably includes a conductive film that reflects visible light in a portion thereof located on the EL layer 115 side. Examples of the conductive film include metal materials such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, and palladium, and alloys containing these metal materials. Silver is preferable because it has a high reflectance to visible light. Aluminum is also preferable because it is easy to process since electrodes can be easily etched and has a high reflectance to visible light and near-infrared light. Lanthanum, neodymium, germanium, or the like may be added to the metal materials or alloys. An alloy containing aluminum with titanium, nickel, or neodymium (aluminum alloy) may also be used. An alloy containing silver with copper, palladium, or magnesium may also be used. An alloy containing silver and copper is preferable because it has high heat resistance.

[0113] The conductive layer 111 may also have a structure in which a conductive metal oxide film is stacked over a conductive film that reflects visible light. Such a structure can suppress oxidation or corrosion of the conductive film that reflects visible light. For example, stacking a metal film or a metal oxide film in contact with an aluminum film or an aluminum alloy film can suppress oxidation. Examples of materials for such metal films and metal oxide films include titanium and titanium oxide. Alternatively, the conductive film that transmits visible light and a film made of a metal material may be stacked. For example, a stacked film of silver and indium tin oxide, or a stacked film of an alloy of silver and magnesium and indium tin oxide can be used.

[0114] When aluminum is used for the conductive layer 111, the thickness is preferably 40 nm or more, more preferably 70 nm or more, to sufficiently increase the reflectance of visible light, etc. When silver is used for the conductive layer 111, the thickness is preferably 70 nm or more, more preferably 100 nm or more, to sufficiently increase the reflectance of visible light, etc.

[0115] A film obtained by forming the above-mentioned conductive film that reflects visible light to a thickness that is thin enough to transmit visible light can be used as a light-transmitting and reflective conductive film that can be used for the conductive layer 116. Furthermore, by using a stacked structure of the conductive film and the above-mentioned conductive film that transmits visible light, conductivity, mechanical strength, and the like can be increased.

[0116] The reflectance of a light-transmitting and reflective conductive film to visible light (for example, the reflectance to light of a predetermined wavelength in the range of 400 nm to 700 nm) is preferably 20% to 80% and more preferably 40% to 70%. The reflectance of a reflective conductive film to visible light is preferably 40% to 100% and more preferably 70% to 100%. The reflectance of a light-transmitting conductive film to visible light is preferably 0% to 40% and more preferably 0% to 30%.

[0117] The conductive layer 111 functioning as the lower electrode can be made of a metal material such as aluminum, yttrium, zirconium, gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, tantalum, or titanium, an alloy containing these metal materials, or a nitride of these metal materials (for example, titanium nitride). These can also be suitably used as the conductive film of the plug 131.

[0118] The electrodes constituting the light-emitting element may be formed by vapor deposition, sputtering, or the like. Alternatively, they may be formed by a discharge method such as an ink-jet method, a printing method such as a screen printing method, or a plating method.

[0119] The above-described light-emitting layer and the layer containing a substance having a high hole-injecting property, a substance having a high hole-transporting property, a substance having a high electron-transporting property, a substance having a high electron-injecting property, a bipolar substance, or the like may each contain an inorganic compound such as quantum dots or a polymer compound (oligomer, dendrimer, polymer, or the like). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

[0120] Examples of quantum dot materials that can be used include colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, and core quantum dot materials. Materials containing elements from groups 12 and 16, 13 and 15, or 14 and 16 may also be used. Quantum dot materials containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, and aluminum may also be used.

[0121] It is preferable that each light-emitting element is adjusted so that the optical distance between the surface of the reflective layer that reflects visible light and the conductive layer 116 that is transparent and reflective to visible light is m×λ / 2 (m is an integer of 1 or greater) or close to that value, where λ is the wavelength of light whose intensity is to be increased.

[0122] It is difficult to precisely adjust the optical distance described above because it is related to the product of the physical distance between the reflective surface of the reflective layer and the reflective surface of the conductive layer 116 that has light-transmitting and reflecting properties and the refractive index of the layer provided therebetween. Therefore, it is preferable to adjust the optical distance by assuming that the surface of the reflective layer and the surface of the conductive layer 116 that has light-transmitting and reflecting properties are each a reflective surface.

[0123] Examples of materials that can be used for the plug 131 include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, gold, silver, platinum, magnesium, iron, cobalt, palladium, tantalum, and tungsten, alloys containing these metal materials, and nitrides of these metal materials. Also, as the plug 131, a film containing these materials can be used as a single layer or as a multilayer structure. Examples of suitable structures include a single-layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is laminated on a titanium film, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a three-layer structure in which a titanium film or titanium nitride film is laminated on top of an aluminum film or copper film, and a titanium film or titanium nitride film is further formed on top of that, and a three-layer structure in which a molybdenum film or molybdenum nitride film is laminated on top of an aluminum film or copper film, and a molybdenum film or molybdenum nitride film is further formed on top of that. Oxides such as indium oxide, tin oxide, or zinc oxide may also be used. Furthermore, using copper containing manganese is preferable because it improves the controllability of the shape by etching.

[0124] [Configuration example of EL layer 115] As shown in FIG. 3A , the EL layer 115 of the light-emitting element 120 can be composed of multiple layers, such as a layer 4420, a light-emitting layer 4411, and a layer 4430. When the conductive layer 111 functions as an anode and the conductive layer 116 functions as a cathode, the layer 4420 can have, for example, a layer containing a substance with high electron injection properties (electron injection layer) and a layer containing a substance with high electron transport properties (electron transport layer). The light-emitting layer 4411 can have, for example, a light-emitting compound. The layer 4430 can have, for example, a layer containing a substance with high hole injection properties (hole injection layer) and a layer containing a substance with high hole transport properties (hole transport layer). Note that when the conductive layer 111 functions as a cathode and the conductive layer 116 functions as an anode, the layer 4420 can have, for example, a hole injection layer and a hole transport layer, the light-emitting layer 4411 can have, for example, a light-emitting compound, and the layer 4430 can have, for example, an electron injection layer and an electron transport layer.

[0125] A structure including the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as one light-emitting unit, and the structure of FIG. 3A is referred to as a single structure in this specification.

[0126] 3B shows a modified example of the EL layer 115 included in the light-emitting element 120 shown in Fig. 3A. Specifically, the light-emitting element 120 shown in Fig. 3B includes a layer 4430-1 on the conductive layer 111, a layer 4430-2 on the layer 4430-1, a light-emitting layer 4411 on the layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on the layer 4420-1, and a conductive layer 116 on the layer 4420-2. For example, when the conductive layer 111 is an anode and the conductive layer 116 is a cathode, the layer 4430-1 functions as a hole injection layer, the layer 4430-2 functions as a hole transport layer, the layer 4420-1 functions as an electron transport layer, and the layer 4420-2 functions as an electron injection layer. Alternatively, when the conductive layer 111 is used as a cathode and the conductive layer 116 is used as an anode, the layer 4430-1 functions as an electron injection layer, the layer 4430-2 functions as an electron transport layer, the layer 4420-1 functions as a hole transport layer, and the layer 4420-2 functions as a hole injection layer. With such a layer structure, it is possible to efficiently inject carriers into the light-emitting layer 4411 and increase the efficiency of carrier recombination in the light-emitting layer 4411.

[0127] Note that a configuration in which a plurality of light-emitting layers (light-emitting layer 4411, light-emitting layer 4412, and light-emitting layer 4413) are provided between layer 4420 and layer 4430 as shown in FIG. 3C is also a variation of the single structure.

[0128] Furthermore, as shown in FIG. 3D, a configuration in which a plurality of light-emitting units (EL layer 115a, EL layer 115b) are connected in series via an intermediate layer 4440 is referred to as a tandem structure in this specification. Note that the intermediate layer 4440 may also be referred to as a charge generation layer. Furthermore, in this specification and the like, the configuration as shown in FIG. 3D is referred to as a tandem structure, but is not limited to this, and for example, the tandem structure may also be referred to as a stack structure. Note that by using a tandem structure, a light-emitting element capable of emitting light with high brightness can be obtained.

[0129] 3C and 3D, the layer 4420 and the layer 4430 may have a laminated structure made up of two or more layers, as shown in FIG. 3B.

[0130] 1B and 1C, EL layer 115 is shown as having a two-layer laminate structure. For example, EL layer 115R is composed of layer 113R and layer 114R on layer 113R. EL layer 115G is composed of layer 113G and layer 114G on layer 113G. EL layer 115B is composed of layer 113B and layer 114B on layer 113B.

[0131] In the following, when describing matters common to the layers 113R, 113G, and 113B, the symbols added to the reference numerals may be omitted and the layers may be described as layer 113. Similarly, the layers 114R, 114G, and 114B may be described as layer 114.

[0132] When the conductive layer 111 functions as an anode and the conductive layer 116 functions as a cathode, the layer 114 is a layer including at least an electron injection layer, for example, an electron injection layer. Furthermore, the layer 113 is all of the layers included in the EL layer 115 other than the layer 114. For example, when the light-emitting element 120 has the electron injection layer and the electron transport layer as the layer 4420, and the layer 114 is an electron injection layer, the layer 113 included in the light-emitting element 120 shown in FIG. 3A includes an electron transport layer, a light-emitting layer 4411, and a layer 4430. The layer 113 included in the light-emitting element 120 shown in FIG. 3B includes a layer 4420-1, a light-emitting layer 4411, a layer 4430-2, and a layer 4430-1. The layer 113 included in the light-emitting element 120 shown in FIG. 3C includes an electron transport layer, a light-emitting layer 4411, a light-emitting layer 4412, a light-emitting layer 4413, and a layer 4430. Furthermore, layer 113 included in light-emitting element 120 shown in FIG. 3D includes an electron transport layer, light-emitting layer 4411, layer 4430, intermediate layer 4440, and EL layer 115b.

[0133] In the above configuration, the layer 114 and the layer 134 contain the same material. Note that the "same material" refers to the case where the constituent elements are the same and the composition is approximately the same. Furthermore, the film thickness of the layer 134 is approximately the same as the film thickness of the layer 114.

[0134] [Hole injection layer] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0135] [Hole transport layer] 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 that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 -6 cm 2 A material having a hole mobility of 1 / Vs or more is preferred. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0136] [Electron transport layer] 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 that contains an electron transporting material. The electron transporting material is a material having a molecular weight of 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. Examples of electron-transporting materials that can be used include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and 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 π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0137] [Electron injection layer] The electron injection layer is a layer containing a substance with high electron injection properties. The electron injection layer is a layer for increasing the efficiency of electron injection from the conductive layer 116, and it is preferable to use a material whose work function value of the material used for the conductive layer 116 and whose LUMO level value have a small difference (0.5 eV or less) when compared. Therefore, the electron injection layer may be made of lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO x Alkali metals, alkaline earth metals, such as cesium carbonate, or compounds thereof can be used. Rare earth metal compounds, such as erbium fluoride (ErF3), can also be used. Electrides can also be used in the electron injection layer. Examples of electrides include substances in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum. Note that materials that form the electron transport layer can also be used.

[0138] The electron injection layer may also use a composite material obtained by mixing an organic compound and an electron donor (donor). Such composite materials have excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent at transporting the generated electrons. Specifically, for example, electron transport materials (metal complexes, heteroaromatic compounds, etc.) used in the electron transport layer can be used. The electron donor may be any substance that exhibits electron donating properties to the organic compound. Specifically, alkali metals, alkaline earth metals, or rare earth elements are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides or alkaline earth metal oxides are preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Organic compounds such as tetrathiafulvalene (TTF) can also be used.

[0139] Alternatively, the electron injection layer may be made of a composite material obtained by mixing an organic compound and a metal. The organic compound used here preferably has a LUMO (Lowest Unoccupied Molecular Orbital) level of -3.6 eV to -2.3 eV. Materials having unshared electron pairs are also preferred. The highest occupied molecular orbital (HOMO) and LUMO levels of organic compounds can generally be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, and the like.

[0140] Therefore, the organic compound is preferably a material having an unshared electron pair, such as a heterocyclic compound having a pyridine skeleton, a diazine skeleton (pyrimidine, pyrazine, etc.), or a triazine skeleton.

[0141] Examples of heterocyclic compounds having a pyridine skeleton include 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), and bathophenanthroline (abbreviation: BPhen). Compared to BPhen, NBPhen has a higher glass transition temperature (Tg) and is more heat resistant.

[0142] Furthermore, examples of heterocyclic compounds having a diazine skeleton include 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), and 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f, h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4-{3-[3'-(9H-carbazol-9-yl)]biphenyl-3-yl}benzofuro[3,2-d]pyrimidine (abbreviation: 4mCzBPBfpm), and the like.

[0143] Examples of heterocyclic compounds having a triazine skeleton include 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tz).

[0144] As the metal, it is preferable to use a transition metal belonging to Group 5, 7, 9, or 11 in the periodic table, or a material belonging to Group 13. Examples of such metals include silver (Ag), copper (Cu), aluminum (Al), and indium (In). In this case, the organic compound forms a Singly Occupied Molecular Orbital (SOMO) with the metal.

[0145] The thickness of the electron injection layer is preferably 3 nm or more, more preferably 5 nm or more. The thickness of the electron injection layer is preferably 50 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. This configuration reduces the influence of light absorption by the electron injection layer, making it possible to provide a light-emitting device that exhibits high luminous efficiency. The thickness of the electron injection layer is not limited to the above, and may be any thickness that allows it to function as an electron injection layer. For example, the thickness of the electron injection layer may be 0.5 nm or more, or 1 nm or more. The thickness of the electron injection layer may be 100 nm or less.

[0146] [Example of manufacturing method] An example of a method for manufacturing a display device according to one embodiment of the present invention will be described with reference to FIGS.

[0147] 4 to 9, A1, B1, C1, and D1 in each figure are cross-sectional views corresponding to the portion indicated by the dashed line X1-X2 in Fig. 1A, and A2, B2, C2, and D2 in each figure are cross-sectional views corresponding to the portion indicated by the dashed line Y1-Y2 in Fig. 1A.

[0148] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and ALD. CVD methods include plasma enhanced chemical vapor deposition (PECVD) and thermal CVD. One type of thermal CVD method is metal organic chemical vapor deposition (MOCVD).

[0149] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating.

[0150] Furthermore, when processing the thin film that constitutes the display device, it can be processed using a photolithography method or the like. Alternatively, the thin film may be processed using a nanoimprint method, a sandblasting method, a lift-off method or the like. Furthermore, an island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask. In this specification, the term "island-shaped" refers to a state in which two or more layers made of the same material and formed in the same process are physically separated.

[0151] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0152] 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 of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure can also be performed using immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays can also be used as the light used for exposure. Instead of light used for exposure, an electron beam can also be used. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0153] The thin film can be processed by dry etching, wet etching, sandblasting, etc. The resist mask can be removed by a dry etching process such as ashing, a wet etching process, a wet etching process after a dry etching process, or a dry etching process after a wet etching process.

[0154] As a typical example of a planarization treatment for a thin film, a polishing treatment such as chemical mechanical polishing (CMP) can be suitably used. Alternatively, dry etching or plasma treatment may be used. The polishing treatment, dry etching treatment, and plasma treatment may be performed multiple times, or may be performed in combination. When combined, the order of the steps is not particularly limited, and may be set appropriately according to the unevenness of the surface to be treated.

[0155] To precisely process a thin film to a desired thickness, for example, a CMP method is used. In this method, the thin film is first polished at a constant processing speed until a portion of the top surface thereof is exposed. Then, the thin film is polished at a slower processing speed until the desired thickness is achieved, thereby enabling highly accurate processing.

[0156] Methods for detecting the end point of polishing include an optical method in which light is irradiated onto the surface of the surface to be treated and changes in the reflected light are detected, a physical method in which changes in the polishing resistance that the processing device receives from the surface to be treated are detected, and a method in which magnetic field lines are applied to the surface to be treated and changes in the magnetic field lines due to the eddy currents that are generated are used.

[0157] After the upper surface of the thin film is exposed, the thickness of the thin film can be controlled with high precision by performing a polishing process under conditions of a slow processing speed while monitoring the thickness of the thin film by an optical method such as a laser interferometer. If necessary, the polishing process may be performed multiple times until the thin film reaches the desired thickness.

[0158] [Production method example 1] The following description will be given taking the display device 100 shown in FIGS. 1A to 1C, which is exemplified in the above configuration example, as an example.

[0159] {Preparing the Substrate 101} A substrate having heat resistance sufficient to withstand at least a subsequent heat treatment can be used as the substrate 101. When an insulating substrate is used as the substrate 101, examples include a glass substrate, a quartz substrate, a sapphire substrate, and a ceramic substrate. Also usable are semiconductor substrates such as a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, and an SOI substrate.

[0160] In particular, it is preferable to use the above-mentioned semiconductor substrate or the above-mentioned insulating substrate on which a semiconductor circuit including a semiconductor element such as a transistor is formed as the substrate 101. The semiconductor circuit preferably 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.

[0161] In this embodiment, a substrate on which at least pixel circuits are formed is used as the substrate 101 .

[0162] {Formation of insulating layer 121 and plug 131} An insulating layer 121 is formed on the substrate 101. Then, an opening is formed in the insulating layer 121 at a position where a plug 131 is to be formed, reaching the substrate 101. The opening preferably reaches an electrode or wiring provided on the substrate 101. Then, a conductive film is formed to fill the opening, and then planarization treatment is performed to expose the top surface of the insulating layer 121. This allows the plug 131 embedded in the insulating layer 121 to be formed.

[0163] {Formation of the light-emitting element 120R, the light-emitting element 120G, the light-emitting element 120B, and the structure 132} A conductive film 111f is formed on the insulating layer 121 and the plug 131 (see FIGS. 4A1 and 4A2). The conductive film 111f can be formed by appropriately using a sputtering method, a CVD method, an MBE method, a PLD method, an ALD method, or the like.

[0164] Next, a film 113RF that will become the layer 113R and a sacrificial film 141RF are sequentially formed on the conductive film 111f (see FIGS. 4B1 and 4B2). As will be described in detail later, the sacrificial layer formed by processing the sacrificial film 141RF functions as a protective layer that protects a film (film 113Rf described later) provided below the sacrificial layer from damage in subsequent processes. The sacrificial layer may also function as a mask when processing the film (film 113Rf described later) provided below the sacrificial layer. Therefore, in this specification and the like, the sacrificial layer may be referred to as a mask layer or a protective layer. The sacrificial film that will become the sacrificial layer may also be referred to as a mask film or a protective film.

[0165] The film 113RF includes at least a film containing a light-emitting compound. Alternatively, the film 113RF may have a structure in which one or more films functioning as an electron transport layer, a charge generation layer, a hole transport layer, or a hole injection layer are stacked. The film 113RF can be formed by, for example, a vapor deposition method, a sputtering method, an inkjet method, or the like. However, the present invention is not limited to these methods, and the above-described film formation methods can be used as appropriate.

[0166] The sacrificial film 141RF can be formed by, for example, sputtering, ALD (thermal ALD, PEALD), or vacuum deposition. Note that a formation method that causes less damage to the film that becomes the layer 113 is preferable, and it is more suitable to form the sacrificial film 141RF by using the ALD or vacuum deposition method rather than the sputtering method.

[0167] In addition to these film formation methods, wet film formation methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating may also be used to form the sacrificial film 141RF.

[0168] It is preferable to use a film that can be removed by wet etching for the sacrificial film 141RF. By using wet etching, damage to the film that will become the layer 113 during processing of the sacrificial film 141RF can be reduced compared to when dry etching is used. When wet etching is used, it is preferable to use a chemical solution such as a developer, a tetramethylammonium hydroxide solution (TMAH), diluted hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0169] In the manufacturing method of the display device of this embodiment, it is desirable that the film that becomes the layer 113 is not easily processed in the process of processing the various sacrificial films, and that the various sacrificial films are not easily processed in the process of processing the film that becomes the layer 113. It is desirable to select the material and processing method of the sacrificial film and the processing method of the film that becomes the layer 113 in consideration of these factors.

[0170] The sacrificial film 141RF may be, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic film such as an inorganic insulating film.

[0171] The sacrificial film 141RF may be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or an alloy material containing such a metal material.

[0172] The sacrificial film 141RF can be made of a metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO). Other examples include 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), and indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide). Alternatively, silicon-containing indium tin oxide can be used.

[0173] Instead of the gallium, an element M (wherein M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used. In particular, it is preferable that M is one or more elements selected from gallium, aluminum, and yttrium.

[0174] The sacrificial film 141RF can be made of any of various inorganic insulating films that can be used for the insulating layer 117 or the insulating layer 118. In particular, an oxide insulating film is preferable because it has higher adhesion to the film that becomes the layer 113 than a nitride insulating film. For example, the sacrificial film 141RF can be made of inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide. In particular, forming an aluminum oxide film using the ALD method as the sacrificial film 141RF is preferable because it can reduce damage to the underlying layer (especially the EL layer, etc.).

[0175] Alternatively, the sacrificial film 141RF may be made of a material that is soluble in a chemically stable solvent, at least for the film located at the top of the film 113RF. For example, a material that dissolves in water or alcohol may be used for the sacrificial film 141RF. When forming the sacrificial film 141RF using such a material, it is preferable to dissolve the material in a solvent such as water or alcohol, apply it using the wet film formation method described above, and then perform a heat treatment to evaporate the solvent. In this case, performing the heat treatment under a reduced pressure atmosphere allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the film 113RF.

[0176] Examples of materials that dissolve in water or alcohol include organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, and alcohol-soluble polyamide resins.

[0177] Subsequently, a resist mask 151R is formed on the sacrificial film 141RF (see FIGS. 4B1 and 4B2). Note that the width of the resist mask 151R in the X1-X2 direction is preferably larger than the width of the conductive layer 111R to be formed later.

[0178] The resist mask 151R can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0179] In FIG. 4B1, in a cross-sectional view of the display device 100, the edge of the resist mask 151R is perpendicular or approximately perpendicular to the substrate 101; however, the shape of the edge of the resist mask 151R is not limited to this. The edge of the resist mask 151R may have a tapered or inversely tapered shape. A tapered shape refers to a case where, when the side of a layer (corresponding to the resist mask 151R here) is observed from the cross-sectional direction (a plane perpendicular to the surface of the substrate), the angle formed between the side and the bottom surface of the layer is less than 90°. An inversely tapered shape refers to a case where, when the side of a layer (corresponding to the resist mask 151R here) is observed from the cross-sectional direction (a plane perpendicular to the surface of the substrate), the angle formed between the side and the bottom surface of the layer is greater than 90°. Alternatively, an inversely tapered shape refers to a shape having a side or top that protrudes in a direction parallel to the substrate more than the bottom.

[0180] Subsequently, the sacrificial film 141RF and the film 113RF that are not covered by the resist mask 151R are removed to expose a part of the upper surface of the conductive film 111f (see FIGS. 4C1 and 4C2). This allows the sacrificial layer 141R and the film 113Rf to be formed.

[0181] The sacrificial film 141RF and a portion of the film 113RF can be removed by dry etching or wet etching. Anisotropic dry etching is particularly preferable because it etches the exposed side surfaces of the film 113RF, preventing the pattern of the film 113RF from shrinking after etching. The removal of the portion of the sacrificial film 141RF and the removal of the portion of the film 113RF may be performed under the same conditions or under different conditions.

[0182] Next, the resist mask 151R is removed (see FIGS. 4C1 and 4C2). Note that, by providing the sacrificial layer 141R on the film 113Rf, the film 113Rf is preferably not exposed to chemicals or the like used when removing the resist mask 151R.

[0183] When the above steps are completed, it is preferable that the sacrificial layer 141R remains on the film 113Rf, so that the sacrificial layer 141R can function as a protective layer that protects the film 113Rf from damage in subsequent steps.

[0184] Subsequently, a film 113GF that will become the layer 113G and a sacrificial film 141GF are sequentially formed on the sacrificial layer 141R and the conductive film 111f (see FIGS. 5A1 and 5A2). At this time, as shown in FIG. 5A1, the film 113GF has a region that contacts the side surface of the film 113Rf.

[0185] The description of the film 113RF above can be applied to the method of forming the film 113GF. Also, the description of the sacrificial film 141RF above can be applied to the materials that can be used for the sacrificial film 141GF and the method of forming the sacrificial film 141GF.

[0186] Next, a resist mask 151G is formed on the sacrificial film 141GF (see FIGS. 5A1 and 5A2). As shown in FIG. 5A1, one side of the resist mask 151G is preferably located near one side of the film 113Rf, and more preferably roughly coincident with the one side of the film 113Rf. This allows the light-emitting elements to be arranged at an extremely high density, thereby significantly increasing the resolution of the display device 100.

[0187] The resist mask 151G can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0188] 5A1 and 5A2, in the cross-sectional view of the display device 100, the edge of the resist mask 151G is approximately perpendicular to the substrate 101, but the shape of the edge of the resist mask 151G is not limited to this. The edge of the resist mask 151G may have a tapered shape or an inverse tapered shape.

[0189] Next, the sacrificial film 141GF and the film 113GF that are not covered by the resist mask 151G are removed to expose a part of the upper surface of the conductive film 111f and the upper surface of the sacrificial layer 141R (see FIGS. 5B1 and 5B2). This allows the sacrificial layer 141G and the film 113Gf to be formed.

[0190] Dry etching or wet etching can be used to remove the sacrificial film 141GF and a portion of the film 113GF. Anisotropic dry etching is particularly preferable because it etches the exposed side surfaces of the film 113Gf, preventing the pattern of the film 113Gf from shrinking after etching. The removal of the portion of the sacrificial film 141GF and the removal of the portion of the film 113GF may be performed under the same conditions or under different conditions.

[0191] Furthermore, as shown in FIG. 5B1, the film 113Gf may have a convex portion at the end on the side in contact with the film 113Rf. In this case, the sacrificial layer 141G may have a convex portion in a region overlapping the convex portion of the film 113Gf. Note that FIG. 5B1 shows a configuration in which the ends of the convex portions of the film 113Gf and the sacrificial layer 141G are approximately perpendicular to the substrate 101, but the shapes of the ends of the convex portions of the film 113Gf and the sacrificial layer 141G are not limited to this. The ends of the convex portions of the film 113Gf and / or the sacrificial layer 141G may have a tapered shape.

[0192] Depending on the shape of the resist mask 151G, the method of removing a portion of the sacrificial film 141GF and the film 113GF, and the like, the film 113Gf and / or the sacrificial layer 141G may not have a protrusion.

[0193] Next, the resist mask 151G is removed (see FIGS. 5B1 and 5B2). Note that, by providing the sacrificial layer 141G on the film 113Gf, the film 113Gf is preferably not exposed to chemicals or the like used when removing the resist mask 151G.

[0194] When the above steps are completed, it is preferable that the sacrificial layer 141R remains on the film 113Rf and the sacrificial layer 141G remains on the film 113Gf. This allows the sacrificial layer 141R and the sacrificial layer 141G to function as protective layers that protect the films 113Rf and 113Gf from damage in subsequent steps. While FIG. 5B1 shows a configuration in which the film 113Gf and the sacrificial layer 141G each have a convex portion at their end, the shape of the end of the film 113Gf and the sacrificial layer 141G is not limited thereto. The film 113Gf and / or the sacrificial layer 141G may not have a convex portion at their end.

[0195] Next, a film 113BF to become layer 113B and a sacrificial film 141BF are sequentially formed on the sacrificial layers 141R, 141G, and the conductive film 111f (see FIGS. 5C1 and 5C2). At this time, as shown in FIG. 5C1, the film 113BF has a region in contact with a side surface of the film 113Rf and a region in contact with a side surface of the film 113Gf.

[0196] The description of the film 113RF above can be applied to the method of forming the film 113BF. Also, the description of the sacrificial film 141RF above can be applied to the materials that can be used for the sacrificial film 141BF and the method of forming the sacrificial film 141BF.

[0197] Next, a resist mask 151B is formed on the sacrificial film 141BF (see FIGS. 5C1 and 5C2). As shown in FIG. 5C1, one side of the resist mask 151B is preferably located near one side of the film 113Gf, and more preferably roughly coincident with the one side of the film 113Gf. This allows the light-emitting elements to be arranged at an extremely high density, thereby significantly increasing the resolution of the display device 100. Furthermore, the other side of the resist mask 151B is preferably located near the other side of the film 113Rf, and more preferably roughly coincident with the other side of the film 113Rf. This allows the light-emitting elements to be arranged at an extremely high density, thereby significantly increasing the resolution of the display device 100.

[0198] The resist mask 151B can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0199] 5C1 and 5C2, in the cross-sectional view of the display device 100, the edge of the resist mask 151B is perpendicular or approximately perpendicular to the substrate 101, but the shape of the edge of the resist mask 151B is not limited to this. The edge of the resist mask 151B may have a tapered shape or a reverse tapered shape.

[0200] Next, the sacrificial film 141BF and the film 113BF that are not covered by the resist mask 151B are removed to expose a part of the upper surface of the conductive film 111f, the upper surface of the sacrificial layer 141R, and the upper surface of the sacrificial layer 141G (see FIGS. 5D1 and 5D2). This allows the sacrificial layer 141B and the film 113Bf to be formed.

[0201] Dry etching or wet etching can be used to remove the sacrificial film 141BF and a portion of the film 113BF. Anisotropic dry etching is particularly preferable because it etches the exposed side surfaces of the film 113Bf, preventing the pattern of the film 113Bf from shrinking after etching. The removal of the portion of the sacrificial film 141BF and the removal of the portion of the film 113BF may be performed under the same conditions or under different conditions.

[0202] Furthermore, as shown in FIG. 5D1, the film 113Bf may have a convex portion at each of its end portions on the side in contact with the film 113Rf and on the side in contact with the film 113Gf. In this case, the sacrificial layer 141B may have a convex portion in a region overlapping with the convex portion of the film 113Bf. Note that FIG. 5D1 shows a configuration in which the ends of the convex portions of the film 113Bf and the sacrificial layer 141B are perpendicular or approximately perpendicular to the substrate 101, but the shapes of the ends of the convex portions of the film 113Bf and the sacrificial layer 141B are not limited thereto. The ends of the convex portions of the film 113Bf and / or the sacrificial layer 141B may have a tapered shape.

[0203] Depending on the shape of the resist mask 151B, the method of removing a portion of the sacrificial film 141BF and the film 113BF, and the like, the film 113Bf and / or the sacrificial layer 141B may not have a protrusion.

[0204] Next, the resist mask 151B is removed (see FIGS. 5D1 and 5D2). Note that, by providing the sacrificial layer 141B on the film 113Bf, the film 113Bf is preferably not exposed to chemicals or the like used when removing the resist mask 151B.

[0205] Upon completion of the above steps, it is preferable that the sacrificial layer 141R remains on the film 113Rf, the sacrificial layer 141G remains on the film 113Gf, and the sacrificial layer 141B remains on the film 113Bf. This allows the sacrificial layers 141R, 141G, and 141B to function as protective layers that protect the films 113Rf, 113Gf, and 113Bf from damage in subsequent steps. While FIG. 5D1 illustrates a configuration in which the films 113Gf, 113Bf, 141G, and 141B each have a convex portion at their end, the shape of the end of the films 113Gf, 113Bf, 141G, and 141B is not limited thereto. One or more of the films 113Gf, 113Bf, 141G, and 141B may not have a convex portion at their end.

[0206] Subsequently, the sacrificial layers 141R, 141G, and 141B are removed to expose the upper surfaces of the films 113Rf, 113Gf, and 113Bf (see FIGS. 6A1 and 6A2).

[0207] The sacrificial layers 141R, 141G, and 141B can be removed by wet etching or dry etching, preferably using a method that causes as little damage as possible to the films 113Rf, 113Gf, and 113Bf.

[0208] When inorganic films are used as the sacrificial layers 141R, 141G, and 141B, it is preferable to use wet etching using, for example, a tetramethylammonium hydroxide aqueous solution (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof to remove the sacrificial layers 141R, 141G, and 141B.

[0209] Alternatively, when the sacrificial layers 141R, 141G, and 141B are made of an organic material, the sacrificial layers 141R, 141G, and 141B are preferably removed by dissolving them in a solvent such as water or alcohol.

[0210] Here, various alcohols such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin can be used as the alcohol capable of dissolving the sacrificial layers 141R, 141G, and 141B.

[0211] 6A1 shows a configuration in which each of the films 113Gf and 113Bf has a convex portion at its end, but the shape of each of the ends of the films 113Gf and 113Bf is not limited to this. Depending on the shapes of the ends of the films 113Gf, 113Bf, sacrificial layers 141G, and 141B, the methods for removing the sacrificial layers 141R, 141G, and 141B, and the like, each of the films 113Gf and 113Bf may not have a convex portion at its end.

[0212] After removing the sacrificial layers 141R, 141G, and 141B, it is preferable to perform a drying process to remove water contained inside the films 113Rf, 113Gf, and 113Bf and water adsorbed on the surfaces. For example, it is preferable to perform a heat treatment in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0213] Next, film 114f and conductive film 116f are sequentially formed on film 113Rf, film 113Gf, and film 113Bf (see FIGS. 6B1 and 6B2). When film 113Gf and film 113Bf each have a convex portion at their end, film 114f and conductive film 116f each have a convex portion in an area overlapping with the convex portion of film 113Gf and film 113Bf, as shown in FIG. 6B1. Note that when film 113Gf and film 113Bf each do not have a convex portion at their end, film 114f and conductive film 116f may not each have a convex portion.

[0214] The film 114f may be, for example, a film containing the material that can be used for the electron injection layer. Examples of materials that can be used for the electron injection layer include alkali metals, alkaline earth metals, or their compounds, and composite materials that are mixtures of organic compounds and metals. Specifically, the film 114f may be, for example, a film containing lithium fluoride (LiF), or a film containing NBPhen and Ag.

[0215] The method for forming the film 114f can be the same as that for the film 113RF.

[0216] The conductive film 116f can be formed by, for example, sputtering or vacuum deposition.

[0217] Subsequently, a resist mask 152R, a resist mask 152G, a resist mask 152B, and a resist mask 152P are formed over the conductive film 116f (see FIGS. 6B1 and 6B2).

[0218] In the following description, when matters common to the resist masks 152R, 152G, and 152B are described, the symbols added to the reference numerals may be omitted and the resist masks may be referred to as the resist masks 152.

[0219] The resist mask 152R is formed to overlap with the film 113Rf. The resist mask 152R has a region overlapping with the plug 131. The width of the resist mask 152R in the X1-X2 direction is preferably smaller than the width of the film 113Rf. When the film 114f and the conductive film 116f each have a convex portion, the resist mask 152R preferably does not overlap with the convex portion of the film 114f, and more preferably does not overlap with the convex portion of the conductive film 116f. Note that FIG. 6B1 shows a configuration in which the side surface of the resist mask 152R and the side surface of the convex portion of the conductive film 116f are in contact with each other.

[0220] The resist mask 152G is formed to overlap with the film 113Gf. The resist mask 152G has a region overlapping with the plug 131. The width of the resist mask 152G in the X1-X2 direction is preferably smaller than the width of the film 113Gf. When the film 114f and the conductive film 116f each have a convex portion, the resist mask 152G preferably does not overlap with the convex portion of the film 113Gf, more preferably does not overlap with the convex portion of the film 114f, and further preferably does not overlap with the convex portion of the conductive film 116f. Note that FIG. 6B1 shows a configuration in which the side surface of the resist mask 152G and the side surface of the convex portion of the conductive film 116f are in contact with each other.

[0221] The resist mask 152B is formed to overlap with the film 113Bf. The resist mask 152B has a region overlapping with the plug 131. The width of the resist mask 152B in the X1-X2 direction is preferably smaller than the width of the film 113Bf. When the film 114f and the conductive film 116f each have a convex portion, the resist mask 152B preferably does not overlap with the convex portion of the film 113Bf, more preferably does not overlap with the convex portion of the film 114f, and further preferably does not overlap with the convex portion of the conductive film 116f. Note that FIG. 6B1 shows a configuration in which the side surface of the resist mask 152B is in contact with the side surface of the convex portion of the conductive film 116f.

[0222] Furthermore, the shortest distance from the side surface of resist mask 152R to the side surface of resist mask 152G, which face each other in the X1-X2 direction (distance L1 shown in FIG. 6B1), may be set appropriately depending on the film thickness, processing accuracy, definition, etc. of insulating layer 117. For example, distance L1 is set to 50 nm or more and 600 nm or less, preferably 100 nm or more and 500 nm or less, and more preferably 150 nm or more and 400 nm or less.

[0223] The preferred range of distance L1 can be applied to the shortest distance from the side surface of resist mask 152R to the side surface of resist mask 152B, which face each other in the X1-X2 direction, and also to the shortest distance from the side surface of resist mask 152G to the side surface of resist mask 152B, which face each other in the X1-X2 direction.

[0224] The preferable range of the distance L1 can also be applied to the shortest distance between the opposing side surfaces of the resist masks 152 adjacent to each other in the Y1-Y2 direction.

[0225] With the above configuration, it is possible to arrange light-emitting elements at an extremely high density, and the resolution of the display device 100 can be made extremely high.

[0226] Depending on the resolution of the display device, the side surface of the resist mask 152 of the light-emitting element 120 and the side surface of the conductive film 116f may not be in contact with each other as shown in FIGS. 8A1 and 8A2.

[0227] The resist mask 152P is formed in a region that does not overlap with the film 113Rf, the film 113Gf, and the film 113Bf.

[0228] The resist mask 152 and the resist mask 152P can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0229] Subsequently, the conductive film 116f, the film 114f, the film 113Rf, the film 113Gf, the film 113Bf, and the conductive film 111f that are not covered by the resist mask 152 and the resist mask 152P are removed, thereby exposing a part of the upper surface of the insulating layer 121.

[0230] By the above processing, conductive layer 116 (conductive layer 116R, conductive layer 116G, and conductive layer 116B) and conductive layer 135 are formed from conductive film 116f (see FIGS. 6C1 and 6C2). Because conductive layer 116 and conductive layer 135 are formed by processing conductive film 116f, conductive layer 116 and conductive layer 135 contain the same material.

[0231] Furthermore, layers 114 (layers 114R, 114G, and 114B) and layer 134 are formed from film 114f (see FIGS. 6C1 and 6C2). Since layers 114 and 134 are formed by processing film 114f, layers 114 and 134 contain the same material.

[0232] Furthermore, the layer 113R is formed from the film 113Rf, the layer 113G is formed from the film 113Gf, and the layer 113B is formed from the film 113Bf (see FIGS. 6C1 and 6C2).

[0233] Furthermore, the conductive layer 111 (conductive layer 111R, conductive layer 111G, and conductive layer 111B) and the conductive layer 133 are formed from the conductive film 111f (see FIGS. 6C1 and 6C2). Since the conductive layer 111 and the conductive layer 133 are formed by processing the conductive film 111f, the conductive layer 111 and the conductive layer 133 contain the same material. Furthermore, the conductive layer 111 is electrically connected to the plug 131.

[0234] Dry etching or wet etching can be used to remove part of the conductive film 116f, part of the film 114f, part of the film 113Rf, part of the film 113Gf, part of the film 113Bf, and part of the conductive film 111f. Note that the removal of part of the conductive film 116f, part of the film 114f, part of the film 113Rf, part of the film 113Gf, part of the film 113Bf, and part of the conductive film 111f may be performed under the same conditions or under different conditions.

[0235] The above processing may result in partial removal of insulating layer 121 in areas not overlapping with resist mask 152 and resist mask 152P. At this time, as shown in FIG. 2B , insulating layer 121 has recesses in areas not overlapping with conductive layer 111. In other words, the film thickness of insulating layer 121 in areas not overlapping with conductive layer 111 is thinner than the film thickness of insulating layer 121 in areas overlapping with conductive layer 111.

[0236] Subsequently, the resist mask 152 and the resist mask 152P are removed (see FIGS. 6C1 and 6C2).

[0237] As a result of the above, it is possible to form light-emitting element 120R composed of conductive layer 111R, layer 113R, layer 114R, and conductive layer 116R, light-emitting element 120G composed of conductive layer 111G, layer 113G, layer 114G, and conductive layer 116G, light-emitting element 120B composed of conductive layer 111B, layer 113B, layer 114B, and conductive layer 116B, and structure 132 composed of conductive layer 135, layer 134, and conductive layer 133.

[0238] The order in which the films 113RF, 113GF, and 113BF are formed is not limited to the above. For example, the films may be formed in the order of film 113RF, film 113BF, and film 113GF. Furthermore, the films may be formed first, either film 113GF or film 113BF.

[0239] Furthermore, the manufacturing method may be adjusted appropriately depending on the number of colors of light emitted by the light-emitting elements 120 included in the display device 100. For example, if the number of colors of light emitted by the light-emitting elements 120 included in the display device 100 is two, the steps of forming at least a film containing a light-emitting compound and a sacrificial film, forming a resist mask, removing the sacrificial film and the film not covered by the resist mask, and removing the resist mask may be performed twice. Alternatively, if the number of colors of light emitted by the light-emitting elements 120 included in the display device 100 is four, the steps may be performed four times.

[0240] According to the above-described example of the manufacturing method, by providing a sacrificial layer on the layer 113, the layer 113 is not exposed to chemicals or the like used to remove the resist masks 151R, 151G, and 151B. Therefore, the light-emitting element 120 can be formed without using a metal mask to form the layer 113.

[0241] {Formation of insulating layer 117, insulating layer 118, and conductive layer 139} Subsequently, insulating films 117f and 118f are formed in this order on the conductive layers 116R, 116G, 116B, 135, and 121 (see FIGS. 7A1 and 7A2).

[0242] The insulating film 117f can be formed by appropriately using a sputtering method, a CVD method, an MBE method, a PLD method, an ALD method, or the like. In this embodiment, an aluminum oxide film is formed as the insulating film 117f by an ALD method. The insulating film 117f needs to be formed with good coverage on the side surfaces of the conductive layer 116, the layer 114, the layer 113, and the conductive layer 111. The ALD method can deposit atomic layers one by one on these side surfaces, and therefore the insulating film 117f can be formed with good coverage.

[0243] For example, when forming an aluminum oxide film using the ALD method, two types of gases are used: a source gas made by vaporizing a liquid containing a solvent and an aluminum precursor compound (such as trimethylaluminum (TMA, Al(CH3)3)), and H2O as an oxidizer. Other materials include tris(dimethylamido)aluminum, triisobutylaluminum, and aluminum tris(2,2,6,6-tetramethyl-3,5-heptanedionate).

[0244] The insulating film 118f can be formed as appropriate by a sputtering method, a CVD method, an MBE method, a PLD method, an ALD method, etc. In this embodiment, a silicon nitride film is formed as the insulating film 118f.

[0245] 2A, when the insulating film 118f is formed by a method with low coverage, a gap 137 may be formed between the insulating films 117f and 118f between the light-emitting elements 120. Examples of film formation methods with low coverage include sputtering and CVD.

[0246] Alternatively, two films made of different materials and / or formed by different deposition methods may be deposited as insulating film 118f. For example, an insulating film that will become insulating layer 118a is deposited on insulating film 117f, and an insulating film that will become insulating layer 118b is deposited on the insulating film that will become insulating layer 118a. Specifically, an insulating film that will become insulating layer 118a is deposited on insulating film 117f by sputtering, and an insulating film that will become insulating layer 118b is deposited on the insulating film that will become insulating layer 118a by ALD. In this way, if a pinhole or a step is formed in the film deposited by sputtering, the film deposited by ALD, which has good coverage, can be used to block the portion that overlaps with the pinhole or step.

[0247] Subsequently, a resist mask 153 is formed on the insulating film 118f (see FIGS. 7A1 and 7A2).

[0248] The resist mask 153 can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0249] Next, the insulating films 118f and 117f that are not covered by the resist mask 153 are removed to expose a part of the upper surface of the conductive layer 116 and a part of the upper surface of the conductive layer 135 (see FIGS. 7B1 and 7B2). This allows the insulating layers 118 and 117 to be formed. Each of the insulating layers 118 and 117 has a first opening in a region overlapping with at least a part of the conductive layer 135 and a second opening in a region overlapping with at least a part of the conductive layer 116.

[0250] Subsequently, the resist mask 153 is removed (see FIGS. 7B1 and 7B2).

[0251] Subsequently, a conductive film 139f is formed on the conductive layer 116, the conductive layer 135, and the insulating layer 118 (see FIGS. 7C1 and 7C2). The conductive film 139f can be formed by appropriately using a sputtering method, a CVD method, an MBE method, a PLD method, an ALD method, or the like.

[0252] Subsequently, a resist mask 154 is formed on the conductive film 139f (see FIGS. 7C1 and 7C2).

[0253] The resist mask 154 can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0254] Next, the conductive film 139f not covered by the resist mask 154 is removed to expose a portion of the upper surface of the insulating layer 118 (see FIGS. 7D1 and 7D2). This allows the conductive layer 139 to be formed. The conductive layer 139 has a region in contact with the conductive layer 135 through a first opening provided in the insulating layer 117 and the insulating layer 118. The conductive layer 139 also has a region in contact with the conductive layer 116 through a second opening provided in the insulating layer 117 and the insulating layer 118.

[0255] Subsequently, the resist mask 154 is removed (see FIGS. 7D1 and 7D2).

[0256] In this manner, the display device 100 can be manufactured.

[0257] Note that the conductive layer 139 is formed uniformly in a region overlapping with the light-emitting element 120 and the structure 132, and therefore may not require fine processing. Therefore, the conductive layer 139 may be formed using a metal mask in some cases. For example, as shown in FIGS. 8B1 and 8B2, the conductive layer 139 may be formed in the region 171 using a metal mask. When the conductive layer 139 is formed using a metal mask, the steps of forming the resist mask 154, removing the conductive film not covered by the resist mask 154, and removing the resist mask 154 can be omitted. Therefore, productivity can be improved by reducing the number of steps.

[0258] According to the above-described example of the manufacturing method, the difference in optical path length between the conductive layer 111 and the conductive layer 116 can be precisely controlled by adjusting the thickness of the EL layer 115. This makes it possible to easily manufacture a display device that is less likely to have deviations in chromaticity between the light-emitting elements, has excellent color reproducibility, and has extremely high display quality.

[0259] Furthermore, the light-emitting element 120 can be formed on an insulating layer 121 having a planarized upper surface. Furthermore, since the lower electrode (conductive layer 111) of the light-emitting element 120 can be configured to be electrically connected to a pixel circuit or the like of the substrate 101 via a plug 131, it is possible to configure extremely fine pixels, and an extremely high-definition display device can be realized. Furthermore, since the light-emitting element 120 can be arranged overlapping the pixel circuit or the drive circuit, a display device with a high aperture ratio (effective light-emitting area ratio) can be realized.

[0260] [Production method example 2] The following description will be given taking the display device 100 shown in FIG. 2C, which is exemplified in the above configuration example, as an example.

[0261] In the following, parts that overlap with the above-mentioned Preparation Method Example 1 will be referred to, and explanations thereof may be omitted.

[0262] {Preparing the Substrate 101} As in the above, a substrate on which at least pixel circuits are formed is used as the substrate 101 .

[0263] {Formation of insulating layer 121 and plug 131} Subsequently, the insulating layer 121 and the plug 131 are formed (see FIGS. 4A1 and 4A2). The insulating layer 121 and the plug 131 can be formed by the same method as described above.

[0264] {Formation of the light-emitting element 120R, the light-emitting element 120G, the light-emitting element 120B, and the structure 132} Subsequently, the films 113Rf, 113Gf, and 113Bf are formed on the conductive film 111f (see FIGS. 6A1 and 6A2). The films 113Rf, 113Gf, and 113Bf can be formed by the same method as described above.

[0265] Subsequently, a film 114f is formed on the films 113Rf, 113Gf, and 113Bf (see FIGS. 9A1 and 9A2).

[0266] As shown in FIG. 9A2, the film 114f is not formed in the region where the structure 132 is to be formed. In other words, the film 114f is formed in the region where the structure 132 is not to be formed. For example, the region where the film 114f is formed is the region 172 shown in FIG. 9A2. The region 172 is the region where the light-emitting element 120 is to be formed, and is the region where the structure 132 is not to be formed. In this case, it is preferable to use a metal mask for forming the film 114f. With this configuration, the film 114f is not formed in the region where the structure 132 is to be formed.

[0267] Subsequently, a conductive film 116f is formed on the film 114f, and a resist mask 152 (resist mask 152R, resist mask 152G, and resist mask 152B) and a resist mask 152P are formed on the conductive film 116f (see FIGS. 9A1 and 9A2). The conductive film 116f and the resist masks 152 and 152P can be formed by the same method as described above.

[0268] The conductive film 116f may be formed over the entire upper surface of the conductive film 111f, or may be formed in a region 171 as shown in Fig. 9A2. When the conductive film 116f is formed in the region 171, the metal mask used when forming the conductive layer 139 can be used.

[0269] Subsequently, the conductive film 116f, the film 114f, the film 113Rf, the film 113Gf, the film 113Bf, and the conductive film 111f that are not covered by the resist mask 152 and the resist mask 152P are removed, and then the resist mask 152 and the resist mask 152P are removed (see FIGS. 9B1 and 9B2). The conductive film 116f, the film 114f, the film 113Rf, the film 113Gf, the film 113Bf, and the conductive film 111f that are not covered by the resist mask 152 and the resist mask 152P, and the resist mask 152 and the resist mask 152P can be removed by the same method as described above.

[0270] As described above, the light emitting element 120R, the light emitting element 120G, the light emitting element 120B, and the structural body 132 constituted by the conductive layer 133 and the conductive layer 135 can be formed.

[0271] The method for forming the structure 132 including the conductive layer 133 and the conductive layer 135 is not limited to the above. For example, the structure 132 including the conductive layer 133 and the conductive layer 135 may be formed through a process of depositing the film 114f, removing the film 114f in an area overlapping with the structure 132, and then depositing the conductive film 116f.

[0272] 4B2, 5A2, and 5C2, the films 113RF, 113GF, and 113BF may be formed over the entire upper surface of the conductive film 111f, but this is not limitative. The films 113RF, 113GF, and 113BF do not have to be formed in the region where the structure 132 is formed. For example, the region where the films 113RF, 113GF, and 113BF are formed may be the region 172 shown in FIGS. 9C1 and 9C2. In this case, the metal mask used when forming the film 114f can be used.

[0273] [Configuration example 2] An example of a display device including a transistor will be described below.

[0274] [Configuration Example 2-1] FIG. 10 is a schematic cross-sectional view of the display device 200A.

[0275] The display device 200A includes a substrate 201, a light emitting element 120R, a light emitting element 120G, a light emitting element 120B, a capacitor element 240, a transistor 210, and the like.

[0276] The laminated structure from the substrate 201 to the capacitive element 240 corresponds to the substrate 101 in the first configuration example.

[0277] The transistor 210 is a transistor in which a channel formation region is formed in a substrate 201. The substrate 201 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 210 includes a part of the substrate 201, a conductive layer 211, a low-resistance region 212, an insulating layer 213, an insulating layer 214, and the like. The conductive layer 211 functions as a gate electrode. The insulating layer 213 is located between the substrate 201 and the conductive layer 211 and functions as a gate insulating layer. The low-resistance region 212 is a region in which the substrate 201 is doped with impurities and functions as either a source or a drain. The insulating layer 214 is provided to cover a side surface of the conductive layer 211 and functions as an insulating layer.

[0278] In addition, an element isolation layer 215 is provided between two adjacent transistors 210 so as to be embedded in the substrate 201 .

[0279] In addition, an insulating layer 261 is provided to cover the transistor 210 , and a capacitor 240 is provided over the insulating layer 261 .

[0280] The capacitor 240 includes a conductive layer 241, a conductive layer 242, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 242 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0281] The conductive layer 241 is provided over the insulating layer 261 and is electrically connected to one of the source and drain of the transistor 210 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 242 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0282] An insulating layer 121 is provided to cover the capacitive element 240, and the light emitting elements 120R, 120G, and 120B are provided on the insulating layer 121. Here, an example is shown in which the light emitting elements 120R, 120G, and 120B are configured as illustrated in Configuration Example 1-1 and FIG. 1B, but the present invention is not limited to this, and various configurations illustrated above can be applied.

[0283] In the display device 200A, insulating layers 161, 162, and 163 are provided in this order to cover the conductive layer 139 on the light-emitting element 120. These three insulating layers function as protective layers to prevent impurities such as water from diffusing into the light-emitting element 120. The insulating layers 161 and 163 are preferably made of inorganic insulating films with low moisture permeability, such as silicon oxide, silicon nitride, or aluminum oxide. The insulating layer 162 can be made of an organic insulating film with high light transmissivity. Using an organic insulating film for the insulating layer 162 reduces the influence of unevenness below the insulating layer 162, thereby smoothing the surface on which the insulating layer 163 is formed. This reduces the likelihood of defects such as pinholes occurring in the insulating layer 163, thereby further improving the moisture permeability of the protective layer. The configuration of the protective layer covering the light-emitting element 120 is not limited to this, and it may be a single-layer structure, a two-layer structure, or a stacked structure of four or more layers.

[0284] On the insulating layer 163, a colored layer 165R overlapping the light-emitting element 120R, a colored layer 165G overlapping the light-emitting element 120G, and a colored layer 165B overlapping the light-emitting element 120B are provided. For example, the colored layer 165R transmits red light, the colored layer 165G transmits green light, and the colored layer 165B transmits blue light. This increases the color purity of the light from each light-emitting element, resulting in a display device with higher display quality. Furthermore, by forming each colored layer on the insulating layer 163, it is easier to align each light-emitting unit with each colored layer than when the colored layers are formed on the substrate 202 (described later), and a display device with extremely high resolution can be realized.

[0285] The display device 200A has a substrate 202 on the viewing side. The substrate 202 and the substrate 201 are bonded together by a light-transmitting adhesive layer 164. The substrate 202 may be a light-transmitting substrate such as a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate.

[0286] With this configuration, a display device with extremely high definition and high display quality can be realized.

[0287] [Configuration Example 2-2] 11 is a schematic cross-sectional view of the display device 200 B. The display device 200 B differs from the display device 200 A mainly in the configuration of the transistors.

[0288] The transistor 220 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0289] The transistor 220 includes a semiconductor layer 221, an insulating layer 223, a conductive layer 224, a pair of conductive layers 225, an insulating layer 226, a conductive layer 227, and the like.

[0290] The substrate 201 on which the transistor 220 is provided can be the insulating substrate or semiconductor substrate described above.

[0291] An insulating layer 232 is provided over the substrate 201. The insulating layer 232 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 201 to the transistor 220 and prevents oxygen from being released from the semiconductor layer 221 toward the substrate 201. The insulating layer 232 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0292] A conductive layer 227 is provided over the insulating layer 232, and an insulating layer 226 is provided to cover the conductive layer 227. The conductive layer 227 functions as a first gate electrode of the transistor 220, and part of the insulating layer 226 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 226 that is in contact with the semiconductor layer 221. The top surface of the insulating layer 226 is preferably planarized.

[0293] The semiconductor layer 221 is provided over the insulating layer 226. The semiconductor layer 221 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor characteristics. Materials that can be suitably used for the semiconductor layer 221 will be described in detail later.

[0294] The pair of conductive layers 225 is provided over and in contact with the semiconductor layer 221 and functions as a source electrode and a drain electrode.

[0295] An insulating layer 228 is provided to cover top surfaces and side surfaces of the pair of conductive layers 225 and side surfaces of the semiconductor layer 221, and an insulating layer 261b is provided over the insulating layer 228. The insulating layer 228 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 261b or the like to the semiconductor layer 221 and prevents oxygen from being released from the semiconductor layer 221. The insulating layer 228 can be an insulating film similar to the insulating layer 232.

[0296] An opening is provided in the insulating layer 228 and the insulating layer 261b, reaching the semiconductor layer 221. An insulating layer 223 and a conductive layer 224 are buried inside the opening and are in contact with the side surfaces of the insulating layer 261b, the insulating layer 228, and the conductive layer 225, as well as the upper surface of the semiconductor layer 221. The conductive layer 224 functions as a second gate electrode, and the insulating layer 223 functions as a second gate insulating layer.

[0297] The upper surfaces of the conductive layer 224, the insulating layer 223, and the insulating layer 261b are flattened so that they are at roughly the same height, and insulating layers 229 and 261a are provided to cover them.

[0298] In this specification, "approximately the same height" refers to a configuration in which the heights from a reference surface (e.g., a flat surface such as a substrate surface) are equal in cross-sectional view. For example, in the manufacturing process of a semiconductor device, a planarization process (typically a CMP process) may be performed to expose the surface of a single layer or multiple layers. In this case, the surfaces processed by the CMP process are configured to be equal in height from the reference surface. "Approximately the same height" also includes cases in which the heights are equal. However, the heights of multiple layers may differ depending on the processing equipment, processing method, or material of the processed surface during the CMP process. In this specification, this case is also considered to be "approximately the same height." For example, when there are two layers (here, a first layer and a second layer) with different heights relative to the reference surface, the difference in height between the top surface of the first layer and the top surface of the second layer is 20 nm or less, this is also considered to be "approximately the same height."

[0299] The insulating layers 261a and 261b function as interlayer insulating layers. The insulating layer 229 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 261a or the like to the transistor 220. The insulating layer 229 can be formed using an insulating film similar to the insulating layer 228 and the insulating layer 232.

[0300] A plug 271 electrically connected to one of the pair of conductive layers 225 is provided so as to be embedded in the insulating layer 261a, the insulating layer 229, and the insulating layer 261b. Here, the plug 271 preferably has a conductive layer 271a covering the side surfaces of the openings of the insulating layer 261a, the insulating layer 261b, the insulating layer 229, and the insulating layer 228 and a part of the upper surface of the conductive layer 225, and a conductive layer 271b in contact with the upper surface of the conductive layer 271a. In this case, the conductive layer 271a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0301] [Configuration Example 2-3] 12 is a schematic cross-sectional view of a display device 200C. The display device 200C has a stacked configuration of a transistor 210 having a channel formed in a substrate 201 and a transistor 220 having a channel formed in a semiconductor layer containing a metal oxide.

[0302] An insulating layer 261 is provided to cover the transistor 210, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layer 251 and the conductive layer 252 each function as a wiring. An insulating layer 263 and an insulating layer 232 are provided to cover the conductive layer 252, and a transistor 220 is provided over the insulating layer 232. An insulating layer 265 is provided to cover the transistor 220, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 220 are electrically connected to each other by a plug 274.

[0303] The transistor 220 can be used as a transistor included in a pixel circuit. The transistor 210 can be used as a transistor included in a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistors 210 and 220 can be used as transistors included in various circuits such as an arithmetic circuit or a memory circuit.

[0304] By using this configuration, not only pixel circuits but also driving circuits etc. can be formed directly below the light-emitting units, making it possible to make the display device smaller than when driving circuits are provided around the periphery of the display area.

[0305] [Configuration Example 2-4] 13 is a schematic cross-sectional view of a display device 200D. The display device 200D differs from the display device 200C described above mainly in that two transistors using an oxide semiconductor are stacked.

[0306] The display device 200D includes a transistor 230 between the transistor 210 and the transistor 220. The transistor 230 has a similar structure to the transistor 220 except that the transistor 230 does not include a first gate electrode. Note that the transistor 230 may include a first gate electrode.

[0307] An insulating layer 263 and an insulating layer 231 are provided to cover the conductive layer 252, and a transistor 230 is provided over the insulating layer 231. The transistor 230 and the conductive layer 252 are electrically connected to each other through a plug 273, the conductive layer 253, and a plug 272. Furthermore, an insulating layer 264 and an insulating layer 232 are provided to cover the conductive layer 253, and a transistor 220 is provided over the insulating layer 232.

[0308] For example, the transistor 220 functions as a transistor for controlling a current flowing through the light-emitting element 120. The transistor 230 functions as a selection transistor for controlling the selection state of the pixel. The transistor 210 functions as a transistor that constitutes a driver circuit for driving the pixel.

[0309] In this way, by stacking three or more layers in which transistors are formed, the area occupied by a pixel can be further reduced, and a high-definition display device can be realized.

[0310] Components such as transistors that can be applied to a display device will be described below.

[0311] [Transistor] The transistor includes a conductive layer functioning as a gate electrode, a semiconductor layer, a conductive layer functioning as a source electrode, a conductive layer functioning as a drain electrode, and an insulating layer functioning as a gate insulating layer.

[0312] Note that the structure of a transistor included in a display device of one embodiment of the present invention is not particularly limited. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Furthermore, a top-gate or bottom-gate transistor structure may be used. Alternatively, gate electrodes may be provided above and below a channel.

[0313] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0314] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably uses a transistor using a metal oxide for a channel formation region (hereinafter referred to as an OS transistor). Metal oxides that can be used for the OS transistor will be described in Embodiment 4.

[0315] Alternatively, silicon may be used as a semiconductor in which a channel of a transistor is formed. Although amorphous silicon may be used as the silicon, it is preferable to use silicon having crystallinity. For example, it is preferable to use microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field-effect mobility and higher reliability than amorphous silicon.

[0316] [Conductive Layer] Materials that can be used for the gate (gate terminal or gate electrode), source (source terminal, source region, or source electrode), and drain (drain terminal, drain region, or drain electrode) of a transistor, as well as conductive layers such as various wirings and electrodes that constitute a display device, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys containing these as main components. Films containing these materials can be used as a single layer or a laminated structure. Examples of suitable structures include a single-layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is laminated on a titanium film, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a three-layer structure in which a titanium film or titanium nitride film is laminated on top of an aluminum film or copper film, and a titanium film or titanium nitride film is further formed on top of that, and a three-layer structure in which a molybdenum film or molybdenum nitride film is laminated on top of an aluminum film or copper film, and a molybdenum film or molybdenum nitride film is further formed on top of that. Oxides such as indium oxide, tin oxide, or zinc oxide may also be used. Furthermore, using copper containing manganese is preferable because it improves the controllability of the shape by etching.

[0317] [Insulating layer] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, resins having siloxane bonds such as silicone, as well as inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0318] In this specification, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0319] Furthermore, the light emitting element is preferably provided between a pair of insulating films with low water permeability, which can prevent impurities such as water from entering the light emitting element and prevent a decrease in the reliability of the device.

[0320] Examples of the insulating film with low water permeability include a film containing nitrogen and silicon, such as a silicon nitride film or a silicon nitride oxide film, or a film containing nitrogen and aluminum, such as an aluminum nitride film. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

[0321] For example, the water vapor permeation rate of a low-permeability insulating film is 1×10 -5 [g / (m 2 ·day)] or less, preferably 1 × 10 -6 [g / (m 2 ·day)] or less, more preferably 1 × 10 -7 [g / (m 2 ·day)] or less, more preferably 1 × 10 -8 [g / (m 2 ·day)] or less.

[0322] [Display module configuration example] A structural example of a display module including a display device of one embodiment of the present invention will be described below.

[0323] 14A is a perspective schematic diagram of a display module 280. The display module 280 includes a display device 200 and an FPC 290. As the display device 200, any of the display devices exemplified in the above configuration example 2 (display device 200A to display device 200D) can be applied.

[0324] The display module 280 has a substrate 201 and a substrate 202. The display module 280 also has a display unit 281 on the substrate 202 side. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 (described later) can be viewed.

[0325] 14B is a perspective view schematically illustrating the configuration on the substrate 201 side. The substrate 201 has a configuration in which a circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked. The substrate 201 also has a terminal portion 285 for connecting to an FPC 290 in a portion of the substrate 201 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0326] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 14B. The pixel 284a has a light emitting element 120R, a light emitting element 120G, and a light emitting element 120B.

[0327] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically. The plurality of pixel circuits 283a may be arranged in a stripe arrangement as shown in Fig. 14B. Various arrangement methods such as a delta arrangement and a pentile arrangement can also be applied.

[0328] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting elements included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting element. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitance element for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0329] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, the circuit portion 282 preferably includes a gate line driver circuit, a source line driver circuit, etc. In addition, the circuit portion 282 may include an arithmetic circuit, a memory circuit, a power supply circuit, etc.

[0330] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit section 282. An IC may also be mounted on the FPC 290.

[0331] The display module 280 can be configured such that the pixel circuit unit 283 or the circuit unit 282 is stacked below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a are arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0332] Such a display module 280 has extremely high resolution and can therefore be suitably used in VR devices such as head-mounted displays or eyeglass-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so that even if the display unit is enlarged with the lenses, the pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices having relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0333] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0334] (Embodiment 2) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0335] 15A includes a pixel portion 502, a driver circuit portion 504, a protective circuit 506, and a terminal portion 507. Note that the display device of one embodiment of the present invention does not necessarily need to include the protective circuit 506.

[0336] The pixel section 502 has a plurality of pixel circuits 501 arranged in X rows and Y columns (X and Y are each independently a natural number of 2 or more). Each pixel circuit 501 has a circuit for driving a display element.

[0337] The driver circuit unit 504 includes driver circuits such as a gate driver 504a that outputs scan signals to the gate lines GL_1 to GL_X and a source driver 504b that supplies data signals to the data lines DL_1 to DL_Y. The gate driver 504a may include at least a shift register. The source driver 504b may include, for example, a plurality of analog switches. Alternatively, the source driver 504b may include a shift register.

[0338] The terminal portion 507 is a portion provided with terminals for inputting power, control signals, image signals, and the like from an external circuit to the display device.

[0339] 15A is connected to various wirings, such as a gate line GL that is a wiring between a gate driver 504a and a pixel circuit 501, or a data line DL that is a wiring between a source driver 504b and a pixel circuit 501.

[0340] Furthermore, the gate driver 504a and the source driver 504b may be provided on the same substrate as the pixel unit 502, or a substrate on which a gate driver circuit or a source driver circuit is separately formed (for example, a drive circuit substrate formed of a single crystal semiconductor or a polycrystalline semiconductor) may be mounted on the substrate by COG or TAB (Tape Automated Bonding).

[0341] In particular, it is preferable to arrange the gate driver 504 a and the source driver 504 b below the pixel section 502 .

[0342] Furthermore, the plurality of pixel circuits 501 shown in FIG. 15A can be configured as shown in FIG. 15B, for example.

[0343] 15B includes a transistor 552, a transistor 554, a capacitor 562, and a light-emitting element 572. The pixel circuit 501 is also connected to a data line DL_n (n is an integer greater than or equal to 1 and less than or equal to Y), a gate line GL_m (m is an integer greater than or equal to 1 and less than or equal to X), a potential supply line VL_a, a potential supply line VL_b, and the like.

[0344] A high power supply potential VDD is applied to one of the potential supply lines VL_a and VL_b, and a low power supply potential VSS is applied to the other. The current flowing through the light-emitting element 572 is controlled in accordance with the potential applied to the gate of the transistor 554, thereby controlling the luminance of light emitted from the light-emitting element 572.

[0345] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0346] (Embodiment 3) A pixel circuit including a memory for correcting a gray scale displayed in a pixel, which can be applied to a display device of one embodiment of the present invention, and a display device including the pixel circuit will be described below.

[0347] [Circuit configuration] 16A shows a circuit diagram of a pixel circuit 400. The pixel circuit 400 includes a transistor M1, a transistor M2, a capacitor C1, and a circuit 401. The pixel circuit 400 is connected to a wiring S1, a wiring S2, a wiring G1, and a wiring G2.

[0348] The transistor M1 has a gate connected to the wiring G1, one of a source and a drain connected to the wiring S1, and the other connected to one electrode of the capacitor C1. The transistor M2 has a gate connected to the wiring G2, one of a source and a drain connected to the wiring S2, and the other connected to the other electrode of the capacitor C1 and the circuit 401.

[0349] The circuit 401 is a circuit including at least one display element. Various elements can be used as the display element, but typically, a light-emitting element such as an organic EL element or an LED element can be used. In addition, a liquid crystal element, a MEMS (Micro Electro Mechanical Systems) element, or the like can also be used.

[0350] The node connecting the transistor M1 and the capacitor C1 is referred to as a node N1, and the node connecting the transistor M2 and the circuit 401 is referred to as a node N2.

[0351] In the pixel circuit 400, the potential of the node N1 can be maintained by turning off the transistor M1. In addition, the potential of the node N2 can be maintained by turning off the transistor M2. In addition, by writing a predetermined potential to the node N1 via the transistor M1 while the transistor M2 is in the off state, the potential of the node N2 can be changed in accordance with the change in the potential of the node N1 due to capacitive coupling via the capacitor C1.

[0352] Here, the transistor including an oxide semiconductor, as exemplified in Embodiment 1, can be used as one or both of the transistor M1 and the transistor M2. Therefore, the potentials of the node N1 and the node N2 can be held for a long period of time due to an extremely small off-state current. Note that when the period for holding the potentials of the nodes is short (specifically, when the frame frequency is 30 Hz or higher), a transistor including a semiconductor such as silicon may be used.

[0353] [Driving method example] Next, an example of an operation method of pixel circuit 400 will be described with reference to Fig. 16B. Fig. 16B is a timing chart relating to the operation of pixel circuit 400. Note that, to simplify the explanation, the influence of various resistances such as wiring resistance, parasitic capacitance of transistors or wiring, threshold voltage of transistors, etc. will not be taken into consideration here.

[0354] 16B, one frame period is divided into period T1 and period T2. Period T1 is a period in which a potential is written to node N2, and period T2 is a period in which a potential is written to node N1.

[0355] [Period T1] In the period T1, a potential that turns on the transistor is applied to both the wiring G1 and the wiring G2. In addition, a fixed potential V ref is supplied to the line S2, and the first data potential V w supply.

[0356] The node N1 is connected to the line S1 via the transistor M1. ref The node N2 is supplied with a first data potential V w Therefore, the capacitance C1 has a potential difference V w -V ref is maintained.

[0357] [Period T2] Subsequently, in a period T2, a potential that turns on the transistor M1 is applied to the wiring G1, and a potential that turns off the transistor M2 is applied to the wiring G2. data A predetermined constant potential is applied to the wiring S2, or the wiring S2 may be in a floating state.

[0358] The node N1 receives a second data potential V data At this time, the second data potential V data In other words, the potential of the node N2 changes by a potential dV in response to the first data potential V w The potential obtained by adding the second data potential V to the potential dV is input. Note that although the potential dV is shown as a positive value in FIG. 16B, it may be a negative value. That is, data is the potential V ref It may be lower.

[0359] Here, the potential dV is roughly determined by the capacitance value of the capacitor C1 and the capacitance value of the circuit 401. When the capacitance value of the capacitor C1 is sufficiently larger than the capacitance value of the circuit 401, the potential dV is equal to the second data potential V data The potential is close to

[0360] In this way, the pixel circuit 400 can combine two types of data signals to generate a potential to be supplied to the circuit 401 including a display element, and therefore, gray scale correction can be performed within the pixel circuit 400.

[0361] The pixel circuit 400 can also generate a potential that exceeds the maximum potential that can be supplied to the wirings S1 and S2. For example, when a light-emitting element is used, high dynamic range (HDR) display or the like can be performed. Furthermore, when a liquid crystal element is used, overdrive driving or the like can be realized.

[0362] [Application example] 16C includes a circuit 401EL. The circuit 401EL includes a light-emitting element EL, a transistor M3, and a capacitor C2.

[0363] The transistor M3 has a gate connected to the node N2 and one electrode of the capacitor C2, and one of its source and drain connected to the potential V H The other electrode of the capacitor C2 is connected to a wiring that supplies a potential V com The other electrode of the light-emitting element EL is connected to a wiring that provides a potential V L Connect with the wiring provided.

[0364] The transistor M3 has a function of controlling the current supplied to the light-emitting element EL. The capacitor C2 functions as a storage capacitor. The capacitor C2 can be omitted if it is not necessary.

[0365] Although the anode side of the light-emitting element EL is connected to the transistor M3 in this example, the transistor M3 may be connected to the cathode side. H and potential V L The value of can be changed as appropriate.

[0366] In the pixel circuit 400EL, by applying a high potential to the gate of the transistor M3, a large current can flow through the light-emitting element EL, thereby realizing, for example, HDR display, etc. Furthermore, by supplying a correction signal to the wiring S1 or the wiring S2, it is possible to correct variations in the electrical characteristics of the transistor M3 or the light-emitting element EL.

[0367] It should be noted that the circuit is not limited to that shown in FIG. 16C, and a configuration in which a separate transistor or capacitor is added may also be used.

[0368] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0369] (Fourth embodiment) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0370] As a semiconductor material for a transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used, typically a metal oxide containing indium.

[0371] The metal oxide preferably contains, for example, indium, M (M is one or more elements selected from gallium, aluminum, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0372] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0373] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include compositions with In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:2 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, In:M:Zn=4:2:3 or thereabouts, In:M:Zn=4:2:4.1 or thereabouts, In:M:Zn=5:1:3 or thereabouts, In:M:Zn=5:1:6 or thereabouts, In:M:Zn=5:1:7 or thereabouts, In:M:Zn=5:1:8 or thereabouts, In:M:Zn=6:1:6 or thereabouts, and In:M:Zn=5:2:5 or thereabouts, etc. Note that "nearby compositions" includes a range of ±30% of the desired atomic ratio.

[0374] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when the atomic ratio of In is 4, the atomic ratio of Ga is 1 to 3 and the atomic ratio of Zn is 2 to 4. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1 and less than 2 and the atomic ratio of Zn is greater than 5 and less than 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when the atomic ratio of In is 1, the atomic ratio of Ga is greater than 0.1 and less than 2 and the atomic ratio of Zn is greater than 0.1 and less than 2.

[0375] Note that an oxide semiconductor having an appropriate composition may be used depending on the semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the transistor that are required. In order to obtain the semiconductor characteristics of the transistor that are required, it is preferable to set the carrier concentration, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like of the semiconductor layer appropriately.

[0376] The metal oxide can be formed by a sputtering method, a CVD method such as an MOCVD method, or an ALD method.

[0377] <Classification of crystal structures> Examples of the crystalline structure of oxide semiconductors include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0378] The crystalline structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectra. For example, it can be evaluated using XRD spectra obtained by GIXD (Grazing-Incidence XRD) measurements. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0379] For example, for a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, for an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum 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.

[0380] The crystalline structure of a film or substrate can also be evaluated by the diffraction pattern (also called the nanobeam electron diffraction pattern) observed using nanobeam 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. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film deposited at room temperature, rather than a halo. For this reason, it is estimated that an IGZO film deposited at room temperature is neither crystalline nor amorphous, but is in an intermediate state, and it cannot be concluded that it is in an amorphous state.

[0381] <<Structure of oxide semiconductor>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0382] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0383] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction can be 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 the atomic arrangement is considered as a lattice arrangement, a crystalline region can also be a region with a uniform lattice arrangement. Furthermore, CAAC-OS has a region where multiple crystalline regions are connected in the ab-plane direction, and the region may have distortion. Note that distortion refers to a location where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor with a c-axis aligned but no clear orientation in the ab-plane direction.

[0384] Each of the multiple crystalline regions 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 one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the maximum diameter of the crystalline region may be several tens of nm.

[0385] In an In-M-Zn oxide (wherein M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and the element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. The In layer may contain M. The In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0386] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD apparatus, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type and composition of the metallic elements constituting the CAAC-OS.

[0387] For example, in the electron diffraction pattern of a CAAC-OS film, multiple bright spots are observed, and the spots are observed at positions that are point-symmetric with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0388] When the crystalline region is observed from the specific direction, the lattice arrangement within the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundaries are observed even near the distortion. This indicates that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed oxygen atom arrangement in the ab-plane direction or the change in interatomic bond distance caused by metal atom substitution.

[0389] A crystal structure with clear grain boundaries is called polycrystalline. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in the on-state current and field-effect mobility of a transistor. Therefore, CAAC-OS, which lacks clear grain boundaries, is one of the crystalline oxides with a crystal structure suitable for use in the semiconductor layer of a transistor. Zn is preferred for use in CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0390] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the decrease in electron mobility due to crystal grain boundaries is unlikely to occur in CAAC-OS. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities or the generation of defects, CAAC-OS can also be said to be an oxide semiconductor with few impurities or defects (such as oxygen vacancies). Therefore, oxide semiconductors with CAAC-OS have stable physical properties. Therefore, oxide semiconductors with CAAC-OS are heat-resistant and highly reliable. Furthermore, CAAC-OS is stable even under high temperatures (so-called thermal budgets) during the manufacturing process. Therefore, using CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0391] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystalline structures. The size of these microcrystalline structures is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore these microcrystalline structures are also called nanocrystalline structures. Furthermore, the nc-OS exhibits no regularity in the crystal orientation between different nanocrystalline structures. Therefore, the entire film lacks orientation. Therefore, depending on the analytical method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD system, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Furthermore, when electron diffraction (also known as selected-area electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of nanocrystalline structures (e.g., 50 nm or larger), a halo-like diffraction 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 nanocrystals (for example, 1 nm to 30 nm), an electron diffraction pattern can be obtained in which multiple spots are observed within a ring-shaped region centered on the direct spot.

[0392] [a-like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0393] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, which relates to the material composition.

[0394] [CAC-OS] CAC-OS is a material structure in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range. Hereinafter, a metal oxide in which one or more metal elements are unevenly distributed and the regions containing the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range, is also referred to as a mosaic or patch state.

[0395] Furthermore, CAC-OS has a mosaic structure in which the material is separated into first and second regions, and the first regions are distributed throughout the film (hereinafter also referred to as a cloud structure). That is, CAC-OS is a composite metal oxide having a structure in which the first and second regions are mixed.

[0396] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In-Ga-Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0397] Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region whose main component is gallium oxide, gallium zinc oxide, or the like. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0398] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0399] In addition, CAC-OS in In-Ga-Zn oxide refers to a material structure containing In, Ga, Zn, and O, in which some regions primarily composed of Ga and other regions primarily composed of In are randomly arranged in a mosaic pattern. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0400] The CAC-OS can be formed, for example, by a sputtering method under conditions where the substrate is not intentionally heated. When the CAC-OS is formed by a sputtering method, any one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition, the better. For example, the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0401] Furthermore, for example, in the case of CAC-OS in an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) confirms that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0402] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0403] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0404] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region complement each other, providing the CAC-OS with a switching function (on / off function). In other words, CAC-OS has a conductive function in some parts of the material and an insulating function in other parts, while the entire material functions as a semiconductor. Separating the conductive and insulating functions maximizes both functions. Therefore, using CAC-OS in a transistor can achieve high on-state current (Ion), high field-effect mobility (μ), and good switching performance.

[0405] Furthermore, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0406] Oxide semiconductors have a variety of structures, each with different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0407] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0408] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0409] For the transistor, an oxide semiconductor with a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than 1 × 10 15 cm -3 or less, more preferably 1 × 10 13 cm -3Less than or equal to 1×10 11 cm -3 or less, more preferably 1 × 10 10 cm -3 Less than 1 x 10 -9 cm -3 That is all. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0410] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states may also be low.

[0411] Furthermore, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0412] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0413] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0414] When an oxide semiconductor contains silicon or carbon, which is a Group 14 element, defect levels are formed 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 calculated to be 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0415] Furthermore, when an oxide semiconductor contains an alkali metal or alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or alkaline earth metal is likely to have normally-on characteristics. Therefore, when the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 Do the following:

[0416] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than 5 × 10, more preferably 17 atoms / cm 3 Do the following:

[0417] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0418] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0419] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0420] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0421] The electronic devices of this embodiment include the display device of one embodiment of the present invention. The display device of one embodiment of the present invention can easily achieve high definition, high resolution, and a large size. Therefore, the display device of one embodiment of the present invention can be used as a display portion of various electronic devices.

[0422] Furthermore, the display device of one embodiment of the present invention can be manufactured at low cost, which leads to a reduction in the manufacturing cost of electronic devices.

[0423] Examples of electronic devices include electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound playback devices.

[0424] In particular, the display device of one embodiment of the present invention can be suitably used in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include head-mounted information terminals (wearable devices), such as glasses-type devices for AR and VR devices such as head-mounted displays, and wearable devices such as wristwatches and bracelets. Examples of wearable devices include devices for SR and MR.

[0425] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280 × 720 pixels), FHD (1920 × 1080 pixels), WQHD (2560 × 1440 pixels), WQXGA (2560 × 1600 pixels), 4K2K (3840 × 2160 pixels), or 8K4K (7680 × 4320 pixels). A resolution of 4K2K, 8K4K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 300 ppi or higher, more preferably 500 ppi or higher, more preferably 1000 ppi or higher, more preferably 2000 ppi or higher, more preferably 3000 ppi or higher, more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using a display device with such high resolution or high definition, it is possible to further enhance the sense of presence and depth in electronic devices for personal use such as portable or home use.

[0426] The electronic device of this embodiment can be incorporated along the curved surface of the inner or outer wall of a house or building, or the interior or exterior of an automobile.

[0427] The electronic device of this embodiment may have an antenna. By receiving a signal through the antenna, images, information, and the like can be displayed on a display portion. In addition, when the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0428] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0429] The electronic device of the present embodiment can have various functions, such as a function 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, time, etc., a function to execute various software (programs), a wireless communication function, a function to read out programs or data recorded on a recording medium, etc.

[0430] 17A shows a perspective view of glasses-type electronic device 700. Electronic device 700 has a pair of display panels 701, a pair of housings 702, a pair of optical members 703, a pair of mounting portions 704, and the like.

[0431] The electronic device 700 can project an image displayed on the display panel 701 onto a display area 706 of the optical member 703. Furthermore, because the optical member 703 is translucent, the user can see the image displayed in the display area 706 superimposed on a transmitted image visually recognized through the optical member 703. Therefore, the electronic device 700 is an electronic device capable of AR display.

[0432] One of the housings 702 is provided with a camera 705 that can capture an image in front of it. Although not shown, one of the housings 702 is provided with a connector to which a wireless receiver or a cable can be connected, and a video signal or the like can be supplied to the housing 702. By providing an acceleration sensor such as a gyro sensor in the housing 702, the orientation of the user's head can be detected and an image corresponding to that orientation can be displayed in the display area 706. The housing 702 is preferably provided with a battery, which can be charged wirelessly or via a wired connection.

[0433] 17B, ​​a method for projecting an image onto display area 706 of electronic device 700 will be described. A display panel 701, a lens 711, and a reflector 712 are provided inside housing 702. In addition, a portion of optical member 703 corresponding to display area 706 has a reflecting surface 713 that functions as a half mirror.

[0434] Light 715 emitted from the display panel 701 passes through the lens 711 and is reflected by the reflector 712 toward the optical member 703. Inside the optical member 703, the light 715 is repeatedly totally reflected at the end face of the optical member 703 and reaches the reflecting surface 713, whereby an image is projected onto the reflecting surface 713. This allows the user to view both the light 715 reflected by the reflecting surface 713 and the transmitted light 716 that has passed through the optical member 703 (including the reflecting surface 713).

[0435] 17 shows an example in which the reflector 712 and the reflecting surface 713 each have a curved surface. This allows for greater freedom in optical design and allows for a thinner optical member 703 than when these surfaces are flat. Note that the reflector 712 and the reflecting surface 713 may also be flat.

[0436] A member having a mirror surface, preferably one with high reflectivity, can be used as the reflector 712. Furthermore, a half mirror utilizing reflection from a metal film may be used as the reflecting surface 713, but the transmittance of the transmitted light 716 can be increased by using a prism or the like utilizing total reflection.

[0437] Here, the housing 702 preferably has a mechanism for adjusting the distance between the lens 711 and the display panel 701 or the angle therebetween. This makes it possible to adjust the focus, enlarge or reduce the image, etc. For example, the lens 711 or the display panel 701 or both may be configured to be movable in the direction of the optical axis.

[0438] Furthermore, it is preferable that the housing 702 has a mechanism that can adjust the angle of the reflector 712. By changing the angle of the reflector 712, it is possible to change the position of the display area 706 where an image is displayed. This makes it possible to position the display area 706 in an optimal position according to the position of the user's eyes.

[0439] The display device or display module of one embodiment of the present invention can be applied to the display panel 701. Therefore, the electronic device 700 can provide an extremely high-resolution display.

[0440] 18A and 18B show perspective views of a goggle-type electronic device 750. Fig. 18A is a perspective view showing the front, top, and left side of electronic device 750, and Fig. 18B is a perspective view showing the back, bottom, and right side of electronic device 750.

[0441] Electronic device 750 includes a pair of display panels 751, a housing 752, a pair of mounting portions 754, buffer members 755, and a pair of lenses 756. The pair of display panels 751 are provided inside housing 752 at positions that can be viewed through lenses 756.

[0442] The electronic device 750 is an electronic device for VR. A user wearing the electronic device 750 can view an image displayed on a display panel 751 through a lens 756. Also, by displaying different images on a pair of display panels 751, a three-dimensional display using parallax can be performed.

[0443] Furthermore, an input terminal 757 and an output terminal 758 are provided on the rear side of the housing 752. A cable for supplying a video signal from a video output device or the like, or power for charging a battery provided within the housing 752, can be connected to the input terminal 757. The output terminal 758 functions as, for example, an audio output terminal, and earphones, headphones, etc. can be connected. Note that if the configuration is such that audio data can be output via wireless communication, or if audio is output from an external video output device, the audio output terminal need not be provided.

[0444] Furthermore, it is preferable that housing 752 has a mechanism that can adjust the left and right positions of lens 756 and display panel 751 so that they are optimally positioned according to the position of the user's eyes.It is also preferable that housing 752 has a mechanism that can adjust the focus by changing the distance between lens 756 and display panel 751.

[0445] The display device or display module of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device 750 can display images with extremely high resolution. This allows the user to feel a high sense of immersion.

[0446] The buffer member 755 is a portion that comes into contact with the user's face (forehead, cheeks, etc.). The close contact of the buffer member 755 with the user's face can prevent light leakage and enhance the sense of immersion. It is preferable to use a soft material for the buffer member 755 so that it can fit snugly against the user's face when the user wears the electronic device 750. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, using a sponge or the like with its surface covered with cloth, leather (natural leather or synthetic leather), or the like can prevent gaps from forming between the user's face and the buffer member 755, thereby effectively preventing light leakage. Furthermore, using such a material is preferable because it feels pleasant to the touch and prevents the user from feeling cold when worn in cold weather. It is preferable to make components that come into contact with the user's skin, such as the buffer member 755 or the attachment portion 754, removable for easy cleaning or replacement.

[0447] 19A to 19F have various functions. For example, they may have a function 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 using various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. Note that the functions of the electronic device are not limited to these, and the electronic device may have various other functions. The electronic device may have multiple display units. Furthermore, the electronic device may have a function to include a camera or the like to capture still images or videos and store them on a recording medium (external or built-in to the camera), a function to display the captured images on the display unit, etc.

[0448] The display device of one embodiment of the present invention can be applied to the display portion 9001 .

[0449] The electronic device shown in FIGS. 19A to 19F will be described in detail below.

[0450] FIG. 19A is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and a display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free communication by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and reception with another information terminal and charge itself via a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0451] FIG. 19B is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. The mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on multiple surfaces thereof. FIG. 19B shows an example in which three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of the email or SNS message, the sender's name, the date and time, the remaining battery level, and the strength of antenna reception. Alternatively, the icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0452] 19C is a perspective view showing a mobile information terminal 9102. The mobile information terminal 9102 has a 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, while the user holds the mobile information terminal 9102 in a breast pocket of their clothes, the user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9102. The user can check the display without taking the mobile information terminal 9102 out of their pocket and decide, for example, whether to answer a call.

[0453] 19D to 19F are perspective views showing a foldable mobile information terminal 9201. FIG. 19D shows the mobile information terminal 9201 in an unfolded state, FIG. 19F shows it in a folded state, and FIG. 19E is a perspective view showing a state in the process of changing from one of FIG. 19D and FIG. 19F to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent viewability of the display. A display unit 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

[0454] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings. [Explanation of symbols]

[0455] DL_1: data line, DL_n: data line, DL_Y: data line, DL: data line, dV: potential, GL_1: gate line, GL_m: gate line, GL_X: gate line, GL: gate line, V com :Potential, V data : Second data potential, VDD: High power supply potential, V H : Potential, VL_a: Potential supply line, VL_b: Potential supply line, V L :Potential, V ref :Potential, VSS: Low power supply potential, V w -V ref :Potential difference, V w:first data potential, 100: display device, 101: substrate, 111: conductive layer, 111B: conductive layer, 111f: conductive film, 111G: conductive layer, 111R: conductive layer, 113: layer, 113B: layer, 113Bf: film, 113BF: film, 113G: layer, 113Gf: film, 113GF: film, 113 R: layer, 113Rf: film, 113RF: film, 114: layer, 114B: layer, 114f: film, 114G: layer, 114R: layer, 115: EL layer, 115a: EL layer, 115b: EL layer, 115B: EL layer, 115G: EL layer, 115R: EL layer, 116: Conductive layer, 116B: Conductive layer, 1 16f: conductive film, 116G: conductive layer, 116R: conductive layer, 117: insulating layer, 117f: insulating film, 118: insulating layer, 118a: insulating layer, 118b: insulating layer, 118f: insulating film, 120: light-emitting element, 120B: light-emitting element, 120G: light-emitting element, 120R: light-emitting element, 121: insulating layer, 131: plug, 132: structure, 133: conductive layer, 134: layer, 135: conductive layer, 137: gap, 139: conductive layer, 139f: conductive film, 141B: sacrificial layer, 141BF: sacrificial film, 141G: sacrificial layer, 141GF: sacrificial film, 141R: sacrificial layer, 141RF: sacrificial film, 151B: Resist mask, 151G: resist mask, 151R: resist mask, 152: resist mask, 152B: resist mask, 152G: resist mask, 152P: resist mask, 152R: resist mask, 153: resist mask, 154: resist mask, 161: insulating layer, 162: insulating layer, 163: insulating layer, 164: adhesive layer, 165B: colored layer, 165G: colored layer, 165R: colored layer, 171: region, 172: region, 200: display device, 200A: display device, 200B: display device, 200C: display device, 200D: display device, 201: substrate Plate, 202: substrate, 210: transistor, 211: conductive layer, 212: low resistance region, 213: insulating layer, 214: insulating layer, 215: element isolation layer, 220: transistor, 221: semiconductor layer, 223: insulating layer, 224: conductive layer, 225: conductive layer, 226: insulating layer, 227: conductive layer, 228: insulating layer, 229: insulating layer, 230: transistor, 231: insulating layer, 232: insulating layer, 240: capacitance element, 241: conductive layer, 242: conductive layer, 243: insulating layer, 251: conductive layer, 252: conductive layer, 253: conductive layer, 261: insulating layer, 261a: insulating layer, 261b: insulating layer,262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 271a: conductive layer, 271b: conductive layer, 272: plug, 273: plug, 274: plug, 280: display module, 281: display section, 282: circuit section, 283: pixel circuit section, 283a: pixel circuit, 284: pixel section, 284a: pixel, 285: terminal section, 286: wiring section, 290: FPC, 400: pixel circuit , 400EL: pixel circuit, 401: circuit, 401EL: circuit, 501: pixel circuit, 502: pixel unit, 504: drive circuit unit, 504a: gate driver, 504b: source driver, 506: protection circuit, 507: terminal unit, 552: transistor, 554: transistor, 562: capacitance element, 572: light-emitting element, 700: electronic device, 701: display panel, 702: housing, 703: optical member, 704: attachment part, 705: camera, 706: display area, 711: lens, 712: reflector, 713: reflective surface, 715: light, 716: transmitted light, 750: electronic device, 751: display panel, 752: housing, 754: mounting part, 755: cushioning material, 756: lens, 757: input terminal, 758: output terminal, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4420-1: layer, 4420-2: layer, 4430: layer, 4430-1: layer, 4430-2: layer, 4440: intermediate layer, 9000: housing, 9001: display unit, 9003: speaker, 9006: connection terminal, 9007: sensor, 9050: icon, 9051: information, 9052: information, 9053: information, 9054: information, 9055: hinge, 9101: mobile information terminal, 9102: mobile information terminal, 9200: mobile information terminal, 9201: mobile information terminal,

Claims

1. a first insulating layer; a light-emitting element and a first conductive layer on the first insulating layer; a first layer on and in contact with the first conductive layer; a second conductive layer on the first layer; and a third conductive layer on the light-emitting element and on the second conductive layer; The light-emitting element is a fourth conductive layer; and a second layer on the fourth conductive layer; and a third layer on the second layer; and a fifth conductive layer on the third layer; the third conductive layer has a region in contact with the second conductive layer and a region in contact with the fifth conductive layer, the second layer comprises a light-emitting compound; the first conductive layer and the fourth conductive layer include the same material; the first layer and the third layer comprise the same material; The display device, wherein the second conductive layer and the fifth conductive layer contain the same material.

2. a first insulating layer; a light-emitting element and a first conductive layer on the first insulating layer; a first layer on and in contact with the first conductive layer; a second conductive layer on the first layer; and a second insulating layer on the light emitting element, the second conductive layer, and the first insulating layer; a third conductive layer on the second insulating layer; The light-emitting element is a fourth conductive layer; and a second layer on the fourth conductive layer; and a third layer on the second layer; and a fifth conductive layer on the third layer; the second insulating layer has regions in contact with a side surface of the fourth conductive layer, a side surface of the second layer, a side surface of the third layer, a side surface of the fifth conductive layer, and a top surface of the fifth conductive layer; The second insulating layer comprises: a first opening having an area overlapping the second conductive layer; a second opening having a region overlapping the fifth conductive layer; The third conductive layer comprises: a region in contact with the second conductive layer through the first opening; a region in contact with the fifth conductive layer through the second opening, the second layer comprises a light-emitting compound; the first conductive layer and the fourth conductive layer include the same material; the first layer and the third layer comprise the same material; The display device, wherein the second conductive layer and the fifth conductive layer contain the same material.

3. In claim 2, the second insulating layer has a laminated structure of a third insulating layer and a fourth insulating layer on the third insulating layer, the third insulating layer has a region in contact with a side surface of the fourth conductive layer, a region in contact with a side surface of the second layer, a region in contact with a side surface of the third layer, a region in contact with a side surface of the fifth conductive layer, and a region in contact with a top surface of the fifth conductive layer; the third insulating layer contains aluminum and oxygen; The fourth insulating layer includes silicon and nitrogen.

4. In any one of claims 1 to 3, The display device, wherein the third layer contains a material with high electron injection property.

5. In any one of claims 1 to 3, The display device, wherein the third layer includes lithium fluoride.

Images