Display device, method for manufacturing display device, display module, and electronic apparatus

Abstract

Provided is a display device that has a high definition or a high resolution. The display device has a first light-emitting element, a second light-emitting element, and a side wall. Each of the first and second light-emitting elements has a pixel electrode, a first light-emitting layer on the pixel electrode, an intermediate layer on the first light-emitting layer, a second light-emitting layer on the intermediate layer, and a common electrode on the second light-emitting layer. In other words, the first and second light-emitting elements can have a tandem structure. The pixel electrode, the first light-emitting layer, the intermediate layer, and the second light-emitting layer are provided separately for each light-emitting element. The first light-emitting element and the second light-emitting element are adjacent to each other, and the side wall is provided between the first light-emitting element and the second light-emitting element. The side wall is provided so as to cover at least part of a side surface of the pixel electrode.

Description

Display device, display device manufacturing method, display module, and electronic device

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

[0002] One embodiment of the present invention is not limited to the above technical field, and examples of the technical field of one embodiment of the present invention include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), driving methods thereof, and manufacturing methods thereof.

[0003] In recent years, display devices have been expected to be used in a variety of applications. For example, applications of large display devices include home television devices (also called televisions or television receivers), digital signage, and public information displays (PIDs). In addition, development of mobile information terminals, such as smartphones and tablet terminals equipped with touch panels, is progressing.

[0004] There is also a demand for higher definition display devices. Devices requiring high-definition display devices, such as devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), are being actively developed.

[0005] As a display device, for example, a light-emitting device having a light-emitting element has been developed. A light-emitting element (also referred to as a light-emitting device, an EL element, or an EL device) utilizing the electroluminescence (hereinafter referred to as EL) phenomenon has features such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power supply, and is therefore applied to a display device.

[0006] Patent Document 1 discloses a display device for VR that uses an organic EL element (also called an organic EL device).

[0007] International Publication No. 2018 / 087625

[0008] When fabricating a display device having multiple organic EL elements, it is preferable to form the light-emitting layers of the organic EL elements in an island shape, i.e., separate them for each organic EL element. This prevents current from flowing between two adjacent light-emitting units through one or more layers shared by the two adjacent light-emitting units, such as a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and an intermediate layer (charge generation layer). This prevents unintended light emission (also known as crosstalk) from the organic EL elements. This improves the contrast of images displayed on the display device, enabling the realization of a display device with high display quality.

[0009] When forming an island-shaped light-emitting layer, for example, a vacuum deposition method using a metal mask (also called a shadow mask) is used. However, during deposition, the contours of the layer may become blurred, resulting in a thin edge. In other words, the island-shaped light-emitting layer may have thickness variations depending on the location. Furthermore, when manufacturing large, high-resolution, or high-definition displays, there is a concern that yields may be low due to the low dimensional accuracy of the metal mask and deformation due to heat, etc.

[0010] Furthermore, when manufacturing a display device using a vacuum deposition method that uses a metal mask, there is a problem that multiple lines of manufacturing equipment are required. For example, since the metal mask needs to be cleaned periodically, at least two or more lines of manufacturing equipment must be prepared, and one manufacturing equipment must be used for manufacturing while the other manufacturing equipment is being maintained. Therefore, considering mass production, multiple lines of manufacturing equipment are required. Therefore, there is a problem that the initial investment for introducing the manufacturing equipment is very large.

[0011] An object of one embodiment of the present invention is to provide a high-resolution display device.An object of one embodiment of the present invention is to provide a high-resolution display device.An object of one embodiment of the present invention is to provide a large-sized display device.An object of one embodiment of the present invention is to provide a highly reliable display device.An object of one embodiment of the present invention is to provide a low-cost display device.An object of one embodiment of the present invention is to provide a novel display device.

[0012] An object of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device.An object of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device.An object of one embodiment of the present invention is to provide a method for manufacturing a large-sized display device.An object of one embodiment of the present invention is to provide a method for manufacturing a highly reliable display device.An object of one embodiment of the present invention is to provide a method for manufacturing a display device with a high yield.An object of one embodiment of the present invention is to provide a novel method for manufacturing a display device.

[0013] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description in the specification, drawings, and claims.

[0014] One embodiment of the present invention is a display device having a first light-emitting element, a second light-emitting element, a first sidewall, and a second sidewall, wherein the first light-emitting element has a first pixel electrode, a first light-emitting layer on the first pixel electrode, a first intermediate layer on the first light-emitting layer, a second light-emitting layer on the first intermediate layer, and a common electrode on the second light-emitting layer, and the second light-emitting element has a second pixel electrode, a third light-emitting layer on the second pixel electrode, a second intermediate layer on the third light-emitting layer, a fourth light-emitting layer on the second intermediate layer, and a common electrode on the fourth light-emitting layer, the first light-emitting element and the second light-emitting element are adjacent to each other, the first sidewall covers at least a part of a side surface of the first pixel electrode, and the second sidewall covers at least a part of a side surface of the second pixel electrode.

[0015] Alternatively, in the above aspect, a gap may be provided between the first side wall and the second side wall.

[0016] Alternatively, one embodiment of the present invention includes a first light-emitting element, a second light-emitting element, a first sidewall, a second sidewall, a third sidewall, and a fourth sidewall. The first light-emitting element includes a first pixel electrode, a first light-emitting layer over the first pixel electrode, a first intermediate layer over the first light-emitting layer, a second light-emitting layer over the first intermediate layer, and a common electrode over the second light-emitting layer. The second light-emitting element includes a second pixel electrode, a third light-emitting layer over the second pixel electrode, a second intermediate layer over the third light-emitting layer, and a fourth light-emitting layer over the second intermediate layer. and a common electrode on the fourth light-emitting layer, the first light-emitting element and the second light-emitting element are adjacent to each other, the first sidewall covers at least a portion of the side surface of the first pixel electrode, the side surfaces of the first and second light-emitting layers, and the side surface of the first intermediate layer, the second sidewall covers at least a portion of the side surface of the first sidewall, the third sidewall covers at least a portion of the side surface of the second pixel electrode, the side surfaces of the third and fourth light-emitting layers, and the side surface of the second intermediate layer, and the fourth sidewall covers at least a portion of the side surface of the third sidewall.

[0017] Alternatively, in the above aspect, a gap may be provided between the second side wall and the fourth side wall.

[0018] Alternatively, in the above aspect, the second side wall may cover at least a portion of the upper surface of the first side wall, and the fourth side wall may cover at least a portion of the upper surface of the third side wall.

[0019] Alternatively, in the above embodiment, a protective layer may be provided on the common electrode, a first colored layer may be provided on the protective layer so as to have an overlapping region with the first light-emitting layer and the second light-emitting layer, and a second colored layer may be provided on the protective layer so as to have an overlapping region with the third light-emitting layer and the fourth light-emitting layer, the first colored layer and the second colored layer having a function of transmitting light of different colors, the first light-emitting layer and the third light-emitting layer having a function of emitting light of the same color, and the second light-emitting layer and the fourth light-emitting layer having a function of emitting light of the same color.

[0020] Alternatively, in the above embodiment, a common layer may be provided between the second and fourth light-emitting layers and the common electrode, and the common layer may function as either an electron injection layer or a hole injection layer in the first and second light-emitting elements.

[0021] Alternatively, in the above aspect, the first pixel electrode and the second pixel electrode may be provided on an insulating layer, and the insulating layer may have a first convex portion in a region overlapping with the first pixel electrode, and the insulating layer may have a second convex portion in a region overlapping with the second pixel electrode.

[0022] Another aspect of the present invention is a display module including a display device according to one aspect of the present invention and at least one of a connector and an integrated circuit.

[0023] An electronic device including a display module of one embodiment of the present invention and at least one of a housing, a battery, a camera, a speaker, and a microphone is also one embodiment of the present invention.

[0024] Alternatively, one embodiment of the present invention includes forming an insulating layer, sequentially depositing a conductive film, a first light-emitting film, an intermediate film, a second light-emitting film, and a sacrificial film over the insulating layer, and etching the sacrificial film, the second light-emitting film, the intermediate film, the first light-emitting film, and the conductive film to form a first pixel electrode and a second pixel electrode over the insulating layer, a first light-emitting layer over the first pixel electrode and a second light-emitting layer over the second pixel electrode, a first intermediate layer over the first light-emitting layer and a second intermediate layer over the second light-emitting layer, a third light-emitting layer over the first intermediate layer and a fourth light-emitting layer over the second intermediate layer, a first sacrificial layer over the third light-emitting layer, and a second sacrificial layer on the fourth light-emitting layer; forming an insulating film that covers at least a portion of the side surfaces of the first and second pixel electrodes, the side surfaces of the first to fourth light-emitting layers, the side surfaces of the first and second intermediate layers, and the side surfaces and top surfaces of the first and second sacrificial layers; etching the insulating film to form a first sidewall that covers at least a portion of the side surface of the first pixel electrode and a second sidewall that covers at least a portion of the side surface of the second pixel electrode; removing the first sacrificial layer and the second sacrificial layer; and forming a common electrode on the third light-emitting layer and the fourth light-emitting layer.

[0025] Alternatively, one embodiment of the present invention includes forming an insulating layer, sequentially depositing a conductive film, a first light-emitting film, an intermediate film, a second light-emitting film, and a sacrificial film over the insulating layer, and etching the sacrificial film, the second light-emitting film, the intermediate film, the first light-emitting film, and the conductive film to form a first pixel electrode and a second pixel electrode over the insulating layer, a first light-emitting layer over the first pixel electrode and a second light-emitting layer over the second pixel electrode, a first intermediate layer over the first light-emitting layer and a second intermediate layer over the second light-emitting layer, a third light-emitting layer over the first intermediate layer and a fourth light-emitting layer over the second intermediate layer, a first sacrificial layer over the third light-emitting layer, and a second sacrificial layer over the fourth light-emitting layer, and forming side surfaces of the first and second pixel electrodes and the first to fourth light-emitting layers. a first insulating film covering at least a portion of the side surfaces of the light-emitting layer, the side surfaces of the first and second intermediate layers, and the side surfaces and top surfaces of the first and second sacrificial layers; a second insulating film on the first insulating film; etching the first insulating film and the second insulating film to form a first side wall covering at least a portion of the side surface of the first pixel electrode, a second side wall covering at least a portion of the side surface of the second pixel electrode, a third side wall covering at least a portion of the side surface of the first side wall, and a fourth side wall covering at least a portion of the side surface of the second side wall; removing the first sacrificial layer and the second sacrificial layer; and forming a common electrode on the third light-emitting layer and the fourth light-emitting layer.

[0026] Alternatively, in the above embodiment, the conductive film may be etched using the first sacrificial layer and the second sacrificial layer as a mask.

[0027] Alternatively, in the above embodiment, a protective layer may be formed on the common electrode, and a first colored layer having an area overlapping with the first and third light-emitting layers and a second colored layer having an area overlapping with the second and fourth light-emitting layers may be formed on the protective layer, and the first colored layer and the second colored layer may have the function of transmitting light of different colors.

[0028] Alternatively, in the above embodiment, after removing the first sacrificial layer and the second sacrificial layer, a common layer that functions as either an electron injection layer or a hole injection layer may be formed on the third light-emitting layer and the fourth light-emitting layer, and a common electrode may be formed on the common layer.

[0029] Alternatively, in the above embodiment, recesses may be formed in the insulating layer in the step of etching the conductive film.

[0030] According to one embodiment of the present invention, a high-definition display device can be provided. According to one embodiment of the present invention, a high-resolution display device can be provided. According to one embodiment of the present invention, a large-sized display device can be provided. According to one embodiment of the present invention, a highly reliable display device can be provided. According to one embodiment of the present invention, a low-cost display device can be provided. According to one embodiment of the present invention, a novel display device can be provided.

[0031] According to one embodiment of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one embodiment of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one embodiment of the present invention, a method for manufacturing a large-sized display device can be provided. According to one embodiment of the present invention, a method for manufacturing a highly reliable display device can be provided. According to one embodiment of the present invention, a method for manufacturing a display device with high yield can be provided. According to one embodiment of the present invention, a method for manufacturing a novel display device can be provided.

[0032] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims.

[0033] FIG. 1 is a top view showing a structural example of a display device. FIGS. 2A to 2E are top views showing a structural example of a display device. FIGS. 3A and 3B are cross-sectional views showing a structural example of a display device. FIG. 3C is a cross-sectional view showing a structural example of a light-emitting unit. FIGS. 4A and 4B are cross-sectional views showing a structural example of a display device. FIG. 4C is a cross-sectional view showing a structural example of a light-emitting unit. FIGS. 5A and 5B are cross-sectional views showing a structural example of a display device. FIGS. 6A and 6B are cross-sectional views showing a structural example of a display device. FIGS. 7A and 7B are cross-sectional views showing a structural example of a display device. FIG. 8 is a top view showing a structural example of a display device. FIGS. 9A and 9B are cross-sectional views showing a structural example of a display device. FIGS. 10A to 10F are top views showing a structural example of a display device. FIGS. 11A to 11E are top views showing an example of a method for manufacturing a display device. FIGS. 12A to 12E are cross-sectional views showing an example of a method for manufacturing a display device. FIGS. 13A and 13B are cross-sectional views showing an example of a method for manufacturing a display device. 14A and 14B are perspective views showing an example of the configuration of a display module. FIG. 15 is a cross-sectional view showing an example of the configuration of a display device. FIG. 16 is a cross-sectional view showing an example of the configuration of a display device. FIG. 17 is a cross-sectional view showing an example of the configuration of a display device. FIG. 18 is a cross-sectional view showing an example of the configuration of a display device. FIG. 19 is a cross-sectional view showing an example of the configuration of a display device. FIGS. 20A and 20B are diagrams showing an example of an electronic device. FIGS. 21A and 21B are diagrams showing an example of an electronic device. FIGS. 22A and 22B are diagrams showing an example of an electronic device. FIGS. 23A to 23D are diagrams showing an example of an electronic device. FIGS. 24A to 24F are diagrams showing an example of an electronic device.

[0034] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0035] 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.

[0036] Furthermore, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0037] It should be noted that the terms "film" and "layer" can be interchangeable depending on the circumstances. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" can be changed to the term "insulating layer."

[0038] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0039] Embodiment 1 In this embodiment, a display device according to one embodiment of the present invention and a manufacturing method thereof will be described with reference to drawings.

[0040] In a method for manufacturing a display device according to one embodiment of the present invention, a conductive film is first formed over an insulating layer. Next, a first layer having a first light-emitting film is formed over the entire surface of the conductive film. Next, an intermediate film is formed over the first layer. Next, a second layer having a second light-emitting film is formed over the entire surface of the intermediate film. After that, a sacrificial film is formed over the second layer.

[0041] Next, a resist mask is formed on the sacrificial film using photolithography or the like. Then, the sacrificial film, the second layer, the intermediate film, the first layer, and the conductive film are etched using the resist mask. As a result, the first pixel electrode on the insulating layer, the first light-emitting unit on the first pixel electrode, the first intermediate layer on the first light-emitting unit, the second light-emitting unit on the first intermediate layer, and the first sacrificial layer on the second light-emitting unit are formed in an island shape. Furthermore, the second pixel electrode on the insulating layer, the third light-emitting unit on the second pixel electrode, the second intermediate layer on the third light-emitting unit, the fourth light-emitting unit on the second intermediate layer, and the second sacrificial layer on the fourth light-emitting unit are formed in an island shape. The first to fourth light-emitting units each have first to fourth light-emitting layers.

[0042] As described above, in the manufacturing method of a display device according to one embodiment of the present invention, island-shaped light-emitting units and the like are formed not by a metal mask pattern but by a photolithography method or the like. Therefore, a high-resolution display device or a display device with a high aperture ratio, which has been difficult to achieve until now, can be realized. Furthermore, since the light-emitting units can be formed in an island shape, a display device with high contrast and high display quality can be realized. Furthermore, by providing a sacrificial layer over the light-emitting units, damage to the light-emitting units during the manufacturing process of the display device can be reduced. This allows a highly reliable display device to be realized.

[0043] Regarding the distance between adjacent light-emitting elements, it is difficult to make it less than 10 μm using a formation method that uses a metal mask, for example, but with the above method, it is possible to narrow it to 3 μm or less, 2 μm or less, or even 1 μm or less.

[0044] Furthermore, the pattern of the light-emitting unit itself can be made much smaller than when a metal mask is used. Furthermore, for example, when a metal mask is used to form the light-emitting unit, thickness variations occur between the center and edges of the pattern, resulting in a smaller effective area that can be used as the light-emitting region relative to the overall area of ​​the pattern. On the other hand, with the above-described manufacturing method, a film formed to a uniform thickness is etched, so island-shaped light-emitting layers, etc., can be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as the light-emitting region. This makes it possible to manufacture a display device that combines high definition and a high aperture ratio.

[0045] As described above, the light-emitting element in the display device of one embodiment of the present invention has a structure in which two or more light-emitting units are stacked with an intermediate layer interposed therebetween. That is, the light-emitting element included in the display device of one embodiment of the present invention can have a tandem structure. In a light-emitting element with a tandem structure, for example, the colors of light emitted by the two stacked light-emitting units can be complementary to each other, so that the light-emitting element can emit white light. Therefore, by providing a colored layer in a region overlapping with the light-emitting element, the display device of one embodiment of the present invention can display, for example, full color images.

[0046] Here, each of the first to fourth light-emitting units includes at least a light-emitting layer, and preferably includes multiple layers. Specifically, it is preferable to have one or more layers on the light-emitting layer. By having another layer between the light-emitting layer and the sacrificial layer, it is possible to prevent the light-emitting layer from being exposed to the outermost surface during the manufacturing process of the display device, thereby reducing damage to the light-emitting layer. This can improve the reliability of the light-emitting element. For example, it is preferable that each of the first to fourth light-emitting units includes a carrier transport layer on the light-emitting layer in addition to the light-emitting layer.

[0047] Note that it is not necessary to form all layers constituting the light-emitting element in an island shape. In a manufacturing method of a display device according to one embodiment of the present invention, after some layers constituting the light-emitting element are formed in an island shape, a sacrificial layer is removed, and the remaining layers constituting the light-emitting element and a common electrode (also referred to as an upper electrode) are formed in common to each light-emitting element. For example, a carrier injection layer and a common electrode can be formed in common to each light-emitting element.

[0048] On the other hand, the carrier injection layer is often a layer with relatively high conductivity in a light-emitting element. Therefore, when the carrier injection layer comes into contact with the side surface of the island-shaped layer, the light-emitting element may be short-circuited. Even when the carrier injection layer is provided in an island shape and a common electrode is formed in common between the light-emitting elements, the light-emitting element may be short-circuited when the common electrode comes into contact with the side surface of the light-emitting unit or the side surface of the pixel electrode.

[0049] Therefore, in a display device according to one embodiment of the present invention, a sidewall (also referred to as a sidewall, a sidewall protective layer, a sidewall insulating film, an insulating layer, or the like) is provided to cover the side surface of the layer formed in an island shape.

[0050] This prevents the island-shaped layer from coming into contact with the carrier injection layer or the common electrode, thereby preventing short circuits in the light-emitting element and improving the reliability of the light-emitting element.

[0051] 1 is a top view illustrating a configuration example of a display device 100, which is a display device according to one embodiment of the present invention. The display device 100 includes a display portion in which a plurality of pixels 110 are arranged in a matrix and a connection portion 140 located outside the display portion. Each pixel 110 includes three subpixels: a subpixel 110a, a subpixel 110b, and a subpixel 110c.

[0052] 1 shows an example in which sub-pixels of different colors are arranged side by side in the X direction, and sub-pixels of the same color are arranged side by side in the Y direction. Note that sub-pixels of different colors may also be arranged side by side in the Y direction, and sub-pixels of the same color may also be arranged side by side in the X direction.

[0053] 1 shows an example in which the connection unit 140 is located below the display unit when viewed from above, but this is not particularly limited. The connection unit 140 only needs to be located in at least one of the upper, right, left, and lower sides of the display unit when viewed from above, and may be located so as to surround all four sides of the display unit. Furthermore, the number of connection units 140 may be singular or plural.

[0054] 1, the sub-pixels 110a, 110b, and 110c are arranged in a stripe pattern. However, the arrangement of the sub-pixels is not limited to the stripe pattern. For example, an S-stripe pattern, a matrix pattern, a delta pattern, a Bayer pattern, a Pentile pattern, or the like can also be used.

[0055] Examples of the top surface shape of the sub-pixel include a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, a circle, etc. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting element.

[0056] 2A to 2C are top views showing an example of the configuration of a pixel 110, which is a modification of the pixel 110 shown in FIG. 1. An S-stripe arrangement is applied to the pixel 110 shown in FIG. 2A. The pixel 110 shown in FIG. 2A is composed of three subpixels: subpixel 110a, subpixel 110b, and subpixel 110c. For example, the subpixel 110a may be a blue subpixel, the subpixel 110b may be a red subpixel, and the subpixel 110c may be a green subpixel.

[0057] The pixel 110 shown in FIG. 2B includes a subpixel 110a having a generally trapezoidal top surface shape with rounded corners, a subpixel 110b having a generally triangular top surface shape with rounded corners, and a subpixel 110c having a generally rectangular or hexagonal top surface shape with rounded corners. The subpixel 110a has a larger light-emitting area than the subpixel 110b. In this manner, the shape and size of each subpixel can be determined independently. For example, the size of a subpixel having a more reliable light-emitting element can be made smaller. For example, the subpixel 110a may be a green subpixel, the subpixel 110b may be a red subpixel, and the subpixel 110c may be a blue subpixel.

[0058] The pixel 125a and pixel 125b shown in Fig. 2C are arranged in a Pentile arrangement. Fig. 2C shows an example in which pixel 125a having subpixels 110a and 110b and pixel 125b having subpixels 110b and 110c are arranged alternately. For example, subpixel 110a may be a blue subpixel, subpixel 110b may be a green subpixel, and subpixel 110c may be a red subpixel.

[0059] 2D and 2E are top views showing configuration examples of the pixel 125a and the pixel 125b. The display device 100 may have a configuration in which a plurality of pixels 125a and a plurality of pixels 125b are arranged in a matrix, instead of the pixel 110.

[0060] 2D and 2E, a delta arrangement is applied to the pixels 125a and 125b. The pixel 125a has two subpixels (subpixels 110a and 110b) in the upper row (first row) and one subpixel (subpixel 110c) in the lower row (second row). The pixel 125b has one subpixel (subpixel 110c) in the upper row (first row) and two subpixels (subpixels 110a and 110b) in the lower row (second row).

[0061] FIG. 2D shows an example in which each subpixel has a substantially rectangular top surface shape with rounded corners, and FIG. 2E shows an example in which each subpixel has a circular top surface shape.

[0062] In photolithography, the finer the etching pattern, the more significant the effect of light diffraction becomes. This reduces the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to etch the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, it is likely to have rounded corners. As a result, the top surface shape of the subpixel may become a polygon with rounded corners, an ellipse, a circle, or the like.

[0063] Furthermore, in a method for manufacturing a display device according to one embodiment of the present invention, a light-emitting unit or the like having a light-emitting layer is etched into an island shape using a resist mask. The resist film formed on the light-emitting unit needs to be cured at a temperature lower than the heat resistance temperature of the light-emitting unit or the like. Therefore, depending on the heat resistance temperature of the material of the light-emitting unit or the like and the curing temperature of the resist material, the resist film may not be cured sufficiently. A resist film that is not cured sufficiently may have a shape different from the desired shape during etching. As a result, the top surface shape of the light-emitting unit or the like may become a polygon with rounded corners, an ellipse, a circle, or the like. For example, when a resist mask with a square top surface shape is formed, a resist mask with a circular top surface shape may be formed, resulting in a circular top surface shape of the light-emitting unit or the like.

[0064] In order to make the top surface of the light-emitting unit or the like have a desired shape, a technique for correcting the mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern match. Specifically, the OPC technique adds a correction pattern to the corners of figures on the mask pattern.

[0065] The display device of one embodiment of the present invention may be any of a top emission type that emits light in a direction opposite to a substrate on which a light-emitting element is formed, a bottom emission type that emits light toward a substrate on which a light-emitting element is formed, and a dual emission type that emits light to both sides.

[0066] 3A is a cross-sectional view showing an example of the configuration between the dashed dotted line X1-X2 in FIG.

[0067] 3A , in the display device 100, light-emitting elements 130 are provided on a layer 101 including transistors, and protective layers 131 and 132 are provided to cover the light-emitting elements. Colored layers 133 (colored layers 133a, 133b, and 133c) are provided on the protective layer 132. A substrate 120 is bonded to the colored layer 133 by a resin layer 119. In addition, sidewalls 121 are provided in the regions between adjacent light-emitting elements 130.

[0068] The transistor-including layer 101 may have, for example, a stacked structure in which a plurality of transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The transistor-including layer 101 may have a recess between adjacent light-emitting elements 130. That is, the transistor-including layer 101 may have a protrusion in a region overlapping with the light-emitting element 130. For example, the recess and the protrusion may be provided in an insulating layer located on the outermost surface of the transistor-including layer 101. A configuration example of the transistor-including layer 101 will be described later in Embodiment 2.

[0069] The light-emitting element 130 has a function of emitting white light, for example. In this specification and the like, a light-emitting element having a function of emitting white light may be referred to as a white light-emitting element. A display device having a white light-emitting element can perform full-color display by combining it with a colored layer (also referred to as a color filter).

[0070] The light-emitting element 130 has a light-emitting unit between a pair of electrodes. In this specification and the like, one of the pair of electrodes may be referred to as a pixel electrode, and the other as a common electrode.

[0071] One of the pair of electrodes of the light-emitting element functions as an anode and the other functions as a cathode. In the following, unless otherwise specified, a case will be described in which the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0072] The light-emitting element 130 includes a pixel electrode 111 on the layer 101 including a transistor, a light-emitting unit 112_1 on the pixel electrode 111, an intermediate layer 113 on the light-emitting unit 112_1, a light-emitting unit 112_2 on the intermediate layer 113, a common layer 114 on the light-emitting unit 112_2, and a common electrode 115 on the common layer 114. Here, the common layer 114 may include, for example, a layer containing a substance with high electron injection properties (electron injection layer). Note that when the pixel electrode 111 functions as a cathode and the common electrode 115 functions as an anode, the common layer 114 may include, for example, a hole injection layer.

[0073] The pixel electrode 111, the light-emitting unit 112, and the intermediate layer 113 are formed in an island shape for each light-emitting element 130. That is, the pixel electrode 111, the light-emitting unit 112, and the intermediate layer 113 are provided separately for each light-emitting element 130. By forming the pixel electrode 111 and the like, the layer 101 including the transistor can have a convex portion in a region overlapping with the pixel electrode 111. Note that the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2 can be collectively referred to as layer 103a.

[0074] In this specification and the like, in order to distinguish between different light-emitting units 112, reference numerals such as _1, _2, etc. are used. Similar notations may be used for other elements.

[0075] A conductive film that transmits visible light is used for the electrode from which light is extracted, either the pixel electrode 111 or the common electrode 115. It is preferable to use a conductive film that reflects visible light for the electrode from which light is not extracted.

[0076] A metal, an alloy, an electrically conductive compound, a mixture thereof, or the like can be appropriately used as a material for forming the pair of electrodes (the pixel electrode 111 and the common electrode 115) of the light-emitting element 130. Specific examples include indium tin oxide (In-Sn oxide, also referred to as ITO), In-Si-Sn oxide (also referred to as ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, an alloy containing aluminum (aluminum alloy) such as an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and an alloy of silver, palladium, and copper (Ag-Pd-Cu, also referred to as APC). Other examples of the metals that can be used include aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), as well as alloys containing appropriate combinations of these metals. Other examples of the metals that can be used include elements belonging to Group 1 or Group 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)), rare earth metals such as europium (Eu), and ytterbium (Yb), as well as alloys containing appropriate combinations of these metals, graphene, and the like.

[0077] A micro-optical resonator (microcavity) structure is preferably applied to the light-emitting element 130. Therefore, one of a pair of electrodes of the light-emitting element 130 preferably has an electrode that is transparent and reflective to visible light (semi-transmissive / semi-reflective electrode), and the other preferably has an electrode that is reflective to visible light (reflective electrode). By having the light-emitting element 130 have a microcavity structure, the light emitted from the light-emitting unit 112 can be resonated between both electrodes, thereby intensifying the light emitted from the light-emitting element 130.

[0078] The semi-transmitting / semi-reflective electrode can have a laminated structure of a reflective electrode and an electrode that is transparent to visible light (also called a transparent electrode).

[0079] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode for the light emitting element 130 that has a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more. The visible light reflectance of the semi-transparent / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 −２ Preferably, it is Ωcm or less.

[0080] 3B is a cross-sectional view showing an example of the configuration between the dashed dotted line Y1-Y2 in FIG. 1 , and is a cross-sectional view showing an example of the configuration of the connection portion 140. The connection portion 140 has a connection electrode 111C on the transistor-containing layer 101, a common electrode 115 on the connection electrode 111C, a protective layer 131 on the common electrode 115, a protective layer 132 on the protective layer 131, a resin layer 119 on the protective layer 132, and a substrate 120 on the resin layer 119. The connection electrode 111C is electrically connected to the common electrode 115.

[0081] 3C is a cross-sectional view showing a detailed configuration example of the layer 103a. The light-emitting unit 112_1 includes, for example, a layer 181, a layer 182 on the layer 181, a light-emitting layer 183_1 on the layer 182, and a layer 184 on the light-emitting layer 183_1. The light-emitting unit 112_2 includes, for example, a layer 182 on the intermediate layer 113, a light-emitting layer 183_2 on the layer 182, and a layer 184 on the light-emitting layer 183_2.

[0082] The layer 181 includes, for example, a layer containing a substance with high hole-injection properties (hole injection layer). The layer 182 includes, for example, a layer containing a substance with high hole-transport properties (hole transport layer). The layer 184 includes, for example, a layer containing a substance with high electron-transport properties (electron transport layer). Here, when the pixel electrode 111 functions as a cathode and the common electrode 115 functions as an anode, the layer 181 includes an electron injection layer or the like. The layer 182 includes an electron transport layer or the like. The layer 184 also includes a hole-transport layer or the like. Note that the light-emitting unit 112 may include a layer containing a substance with high hole-blocking properties (hole blocking layer) or a layer containing a substance with high electron-blocking properties (electron blocking layer).

[0083] Note that the layers 182 and 184 may have the same configuration (material, film thickness, etc.) between the light-emitting unit 112_1 and the light-emitting unit 112_2, or may have different configurations.

[0084] 3C , the layer 181 and the layer 182 are separately illustrated, but the present invention is not limited to this. For example, when the layer 181 has a function as both a hole injection layer and a hole transport layer, or when the layer 181 has a function as both an electron injection layer and an electron transport layer, the layer 182 may be omitted.

[0085] By providing the layer 184 over the light-emitting layer 183_2, exposure of the light-emitting layer 183 to the outermost surface during the manufacturing process of the display device 100 can be suppressed, and damage to the light-emitting layer 183 can be reduced. This can improve the reliability of the light-emitting element 130.

[0086] The intermediate layer 113 has a function of injecting electrons into one of the light-emitting unit 112_1 and the light-emitting unit 112_2 and injecting holes into the other when a voltage is applied between the pixel electrode 111 and the common electrode 115. The intermediate layer 113 can also be called a charge generation layer.

[0087] The color of light emitted by the light-emitting layer 183_1 and the color of light emitted by the light-emitting layer 183_2 can be, for example, complementary colors. This allows the light-emitting element 130 to emit white light as a whole. For example, one of the light-emitting layer 183_1 and the light-emitting layer 183_2 can emit red light and green light, and the other of the light-emitting layer 183_1 and the light-emitting layer 183_2 can emit blue light. Alternatively, one of the light-emitting layer 183_1 and the light-emitting layer 183_2 can emit yellow light or orange light, and the other of the light-emitting layer 183_1 and the light-emitting layer 183_2 can emit blue light. Here, when one light-emitting layer 183 emits light of two or more colors, the light-emitting layer 183 can have a stacked structure of two or more layers. For example, when one light-emitting layer 183 emits red light and green light, the light-emitting layer 183 can have a stacked structure of a layer that emits red light and a layer that emits green light.

[0088] In this specification, a structure in which a plurality of light-emitting units 112 are stacked with an intermediate layer 113 interposed therebetween, as in the light-emitting element 130, is referred to as a tandem structure. On the other hand, a structure in which one light-emitting unit 112 is disposed between a pair of electrodes is referred to as a single structure. Note that the tandem structure can also be referred to as a stack structure, for example. By forming a light-emitting element into a tandem structure, a light-emitting element capable of emitting light with high luminance can be obtained. Furthermore, compared to a single structure, a tandem structure can reduce the current required to obtain the same luminance, thereby reducing the power consumption of the display device and improving the reliability of the light-emitting element.

[0089] Furthermore, a structure in which the light-emitting layer is separated for each light-emitting element, such as the light-emitting element 130, is sometimes called an SBS (Side By Side) structure. The SBS structure allows the material and configuration to be optimized for each light-emitting element, increasing the degree of freedom in selecting the material and configuration, and making it easier to improve the brightness and reliability of the light-emitting element.

[0090] The light-emitting element 130 can be said to have both a tandem structure and an SBS structure. Therefore, it can combine the advantages of both the tandem structure and the SBS structure. Note that, as shown in FIG. 3A , the display device 100 has a structure in which the light-emitting units 112 are formed in two stages in series, so it can also be said to have a two-stage tandem structure.

[0091] Here, the light-emitting element 130 is a white light-emitting element. In other words, the color emitted by the light-emitting element 130 is not varied depending on the color of the sub-pixel. Therefore, the color emitted by the light-emitting layer 183 does not need to be varied for each light-emitting element 130. Therefore, for example, the light-emitting layers 183 of all the light-emitting elements 130 can be formed collectively. Therefore, the display device 100 can be manufactured at a lower cost and with a higher yield than in a case where the color emitted by the light-emitting layer 183 is varied depending on the color of the sub-pixel. Therefore, the display device 100 can be manufactured at a lower price.

[0092] Specific examples of each layer of the light emitting element 130 will be described below.

[0093] 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).

[0094] 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 substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances 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.

[0095] 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 other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0096] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0097] The electron injection layer may be formed of, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF Ｘ , where X is an arbitrary number), 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 such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. The electron injection layer may have a stacked structure of two or more layers. For example, the stacked structure may have a structure in which lithium fluoride is used in the first layer and ytterbium is provided in the second layer.

[0098] Alternatively, the electron injection layer may be formed using a material having electron transport properties. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the material having electron transport properties. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring may be used.

[0099] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) of -3.6 eV to -2.3 eV. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0100] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), etc. can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition point (Tg) and is superior in heat resistance compared to BPhen.

[0101] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can contain one or more light-emitting substances. As the light-emitting substance, a substance that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, or the like is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0102] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0103] 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.

[0104] 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.

[0105] 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). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material can be used.

[0106] The light-emitting layer preferably includes, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material, which are a combination that easily forms an exciplex. This configuration allows efficient emission using Exciplex-Triple 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, energy transfer becomes smooth, allowing efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting element.

[0107] For example, a material applicable to an electron injection layer, such as lithium, can be suitably used for the intermediate layer. For example, a material applicable to a hole injection layer can be suitably used for the intermediate layer. For example, a layer containing a hole transport material and an acceptor material (electron acceptor material) can be used for the intermediate layer. For example, a layer containing an electron transport material and a donor material can be used for the intermediate layer. By forming an intermediate layer having such a layer, an increase in driving voltage can be suppressed when light-emitting units are stacked.

[0108] At least a portion of the side surface of the pixel electrode 111 is covered by the side wall 121. This can prevent the common layer 114 from coming into contact with the side surface of the pixel electrode 111. Furthermore, at least a portion of the side surface of the light-emitting unit 112 and the side surface of the intermediate layer 113 may be covered by the side wall 121. This can prevent the common layer 114 from coming into contact with either the side surface of the light-emitting unit 112 or the intermediate layer 113. As a result, short-circuiting of the light-emitting element 130 can be prevented.

[0109] 3A and 3B show an example in which the side wall 121 has a two-layer structure of a side wall 121a and a side wall 121b. The thickness of the side wall 121b in the X direction and the Y direction can be greater than the thickness of the side wall 121a in the X direction and the Y direction. The end of the side wall 121b can be rounded. By rounding the end of the side wall 121b, coverage of the common layer 114, the common electrode 115, and the protective layer 131 is improved, which is preferable.

[0110] The side wall 121a covers at least a part of the side surface of the pixel electrode 111. The side wall 121a may also cover at least a part of the side surface of the light-emitting unit 112 and the side surface of the intermediate layer 113. The side wall 121b covers the side surface of the side wall 121a and at least a part of the upper surface of the side wall 121a.

[0111] The sidewalls 121a and 121b can be formed using inorganic insulating films such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film.

[0112] The sidewalls 121a and 121b can be formed by various film formation methods, such as sputtering, evaporation, chemical vapor deposition (CVD), and atomic layer deposition (ALD). In particular, the ALD method causes less film formation damage to the layer on which the film is formed, so it is preferable to form the sidewalls 121a, which are formed directly on the light-emitting unit 112 and the intermediate layer 113, by the ALD method. In this case, it is preferable to form the sidewalls 121b by sputtering, because this can increase productivity.

[0113] For example, the sidewall 121a may be formed of an aluminum oxide film by ALD, and the sidewall 121b may be formed of a silicon nitride film by sputtering.

[0114] One or both of the sidewalls 121a and 121b preferably function as a barrier insulating film against at least one of water and oxygen. Alternatively, one or both of the sidewalls 121a and 121b preferably have a function of suppressing diffusion of at least one of water and oxygen. Alternatively, one or both of the sidewalls 121a and 121b preferably have a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0115] In this specification and the like, a barrier insulating film refers to an insulating film having barrier properties. Furthermore, in this specification and the like, the term "barrier properties" refers to a function of suppressing the diffusion of a corresponding substance (also referred to as low permeability), or a function of capturing or fixing a corresponding substance (also referred to as gettering).

[0116] The sidewalls 121 a and 121 b, or both of them, have the above-mentioned barrier insulating film function or gettering function, which can suppress the intrusion of impurities (typically, water or oxygen) that may diffuse into each light-emitting element from the outside. With this configuration, a display device with excellent reliability can be provided.

[0117] Voids 134 may be formed in regions between the light-emitting elements 130 (between the sidewalls 121) and in recesses in the transistor-containing layer 101. FIG. 3A shows an example in which the voids 134 are formed between the transistor-containing layer 101 and the common layer 114. Note that the voids 134 may not be formed depending on the distance between adjacent light-emitting elements 130, the thickness of the common layer 114, the thickness of the common electrode 115, the thickness of the protective layer 131, and the like. In this case, the spaces between adjacent light-emitting elements 130 are filled with at least one of the common layer 114, the common electrode 115, and the protective layer 131. Furthermore, an insulating material may be filled into regions that could become voids.

[0118] The void 134 contains, for example, one or more selected from air, nitrogen, oxygen, carbon dioxide, and Group 18 elements (typically, helium, neon, argon, xenon, krypton, etc.). The void may also contain a gas used during film formation, such as the common layer 114. For example, when the common layer 114 is formed by vacuum deposition, the void may be in a reduced pressure atmosphere. When the void 134 contains a gas, the gas can be identified by gas chromatography or the like.

[0119] Furthermore, when the refractive index of the void 134 is lower than that of the side wall 121, the light emitted from the light-emitting unit 112 is reflected at the interface between the side wall 121 and the void 134. This prevents the light emitted from the light-emitting unit 112 from entering an adjacent pixel (or sub-pixel). This prevents light of different colors from mixing, thereby improving the display quality of the display device.

[0120] Alternatively, an insulating material may be filled into the portion that could become the void 134. The insulating material may be an organic insulating material or an inorganic insulating material, or both. The insulating material may be at least one of a solid material, a gel material, and a liquid material.

[0121] Examples of the organic insulating material include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyimideamide resin, polysiloxane resin, benzocyclobutene resin, and phenol resin. Also, various resins that can be used for the resin layer 119 may be used.

[0122] Examples of inorganic insulating materials include oxide insulating materials, nitride insulating materials, oxynitride insulating materials, and nitride oxide insulating materials. In addition, the insulating materials that can be used for the protective layers 131 and 132 may also be used.

[0123] As described above, the shape of the layer formed after the sidewall 121 is formed can vary depending on the material, the film formation method, the film thickness, etc., and is not particularly limited. The display device of one embodiment of the present invention has a structure in which the sidewall 121 prevents short circuits of the light-emitting element 130. Therefore, the range of options for the material, the film formation method, and the film thickness of the layer formed after the sidewall 121 is formed can be expanded.

[0124] The display device 100 preferably includes a protective layer 131 and a protective layer 132 over the light-emitting element 130. Providing the protective layer 131 and the protective layer 132 can improve the reliability of the light-emitting element 130. Note that the display device 100 does not necessarily include the protective layer 131 or the protective layer 132.

[0125] There is no limitation on the conductivity of the protective layer 131 and the protective layer 132. The protective layer 131 and the protective layer 132 can be formed using at least one of an insulating film, a semiconductor film, and a conductive film.

[0126] The protective layers 131 and 132 each having an inorganic film can suppress oxidation of the common electrode 115 and can also suppress impurities (moisture, oxygen, etc.) from entering the light-emitting element 130. This can suppress deterioration of the light-emitting element 130 and improve the reliability of the display device.

[0127] The protective layer 131 and the protective layer 132 can be formed using an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film.

[0128] In this specification and elsewhere, an oxynitride refers to a material having a composition in which oxygen is contained in a larger amount than nitrogen, and a nitride oxide refers to a material having a composition in which nitrogen is contained in a larger amount than oxygen.

[0129] Each of the protective layers 131 and 132 preferably includes an insulating nitride film or an insulating nitride oxide film, and more preferably includes an insulating nitride film.

[0130] Alternatively, an inorganic film containing In—Sn oxide (also referred to as ITO), In—Zn oxide, Ga—Zn oxide, Al—Zn oxide, indium gallium zinc oxide (In—Ga—Zn oxide, also referred to as IGZO), or the like can be used for the protective layer 131 and the protective layer 132. The inorganic film preferably has high resistance, specifically, preferably has higher resistance than the common electrode 115. The inorganic film may further contain nitrogen.

[0131] When light emitted from the light-emitting element 130 is extracted through the protective layer 131 and the protective layer 132, it is preferable that the protective layer 131 and the protective layer 132 have high transparency to visible light. For example, ITO, IGZO, and aluminum oxide are preferable because they are inorganic materials that have high transparency to visible light.

[0132] For example, a stacked structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a stacked structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used for the protective layer 131 and the protective layer 132. By using such a stacked structure, impurities (water, oxygen, etc.) can be prevented from entering the light-emitting unit 112.

[0133] Furthermore, the protective layer 131 and the protective layer 132 may include an organic film. For example, the protective layer 132 may include both an organic film and an inorganic film.

[0134] Different film formation methods may be used for the protective layer 131 and the protective layer 132. Specifically, the protective layer 131 may be formed by an ALD method, and the protective layer 132 may be formed by a sputtering method.

[0135] A coloring layer 133 is provided on the protective layer 132. The coloring layer 133 has a region overlapping with the light-emitting element 130. Specifically, the coloring layer 133 has a region overlapping with the light-emitting layer 183. FIG. 3A shows an example in which a different coloring layer 133 (coloring layer 133a, coloring layer 133b, or coloring layer 133c) is provided for each light-emitting element 130. The coloring layer 133a, coloring layer 133b, and coloring layer 133c have a function of transmitting light of different colors. For example, the coloring layer 133a has a function of transmitting red light, the coloring layer 133b has a function of transmitting green light, and the coloring layer 133c has a function of transmitting blue light. This enables the display device 100 to perform full-color display. Note that the coloring layer 133a, coloring layer 133b, and coloring layer 133c may have a function of transmitting any of cyan, magenta, and yellow light.

[0136] Here, it is preferable that adjacent colored layers 133 have overlapping regions. Specifically, it is preferable that adjacent colored layers 133 have overlapping regions in regions that do not overlap with the light-emitting units 112. By overlapping the colored layers 133 that transmit light of different colors, the colored layers 133 can function as light-blocking layers in the overlapping regions. This makes it possible to prevent light emitted by the light-emitting elements 130 from leaking to adjacent subpixels. For example, it is possible to prevent light emitted by the light-emitting elements 130 that overlap with the colored layer 133a from being incident on the colored layer 133b. This makes it possible to increase the contrast of images displayed on the display device, thereby realizing a display device with high display quality.

[0137] Note that adjacent colored layers 133 do not necessarily have to have overlapping regions. In this case, it is preferable to provide a light-shielding layer in a region that does not overlap with the light-emitting unit 112. The light-shielding layer can be provided, for example, on the surface of the substrate 120 facing the resin layer 119. Alternatively, the colored layer 133 may be provided on the surface of the substrate 120 facing the resin layer 119.

[0138] The upper end of the pixel electrode 111 is not covered with an insulating layer, so the distance between adjacent light emitting elements 130 can be made extremely small, resulting in a high-definition or high-resolution display device.

[0139] The display device 100 can narrow the distance between the light-emitting elements 130. Specifically, the distance between the light-emitting elements 130 can be 1 μm or less, preferably 500 nm or less, and more preferably 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, for example, there is an area where the distance between the side surface of the light-emitting unit 112 of one light-emitting element 130 and the side surface of the light-emitting unit 112 of an adjacent light-emitting element 130 is 1 μm or less, preferably 0.5 μm (500 nm) or less, and more preferably 100 nm or less.

[0140] In this specification and the like, adjacent elements do not necessarily have to be in contact with each other. For example, even if the light-emitting units 112 of adjacent light-emitting elements 130 are not in contact with each other, the two light-emitting units 112 can still be said to be adjacent.

[0141] Various optical members can be disposed on the outside of the substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. In addition, an antistatic film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses scratches caused by use, an impact absorbing layer, etc. may also be disposed on the outside of the substrate 120.

[0142] The substrate 120 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting element is extracted. Using a flexible material for the substrate 120 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as the substrate 120.

[0143] The substrate 120 may be made of polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. The substrate 120 may be made of glass having a thickness sufficient to provide flexibility.

[0144] When a circularly polarizing plate is superimposed on a display device, it is preferable that the display device has a substrate with high optical isotropy. A substrate with high optical isotropy has small birefringence (or a small amount of birefringence).

[0145] The absolute value of the retardation (phase difference) of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0146] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

[0147] Furthermore, when a film is used as a substrate, the film may absorb water, causing deformation such as wrinkles in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less.

[0148] The resin layer 119 can be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet curable adhesive), a reactive curable adhesive, a thermosetting adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability, such as epoxy resin, is preferable. Alternatively, a two-component resin may be used. Alternatively, an adhesive sheet or the like may be used.

[0149] Materials that can be used for conductive layers such as the gate, source, and drain of a transistor, as well 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 metals as main components, etc. Films containing these materials can be used as a single layer or a stacked layer structure.

[0150] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials, can be used. Alternatively, nitrides of such metal materials (e.g., titanium nitride) can be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin them sufficiently to ensure light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These materials can also be used for conductive layers such as various wirings and electrodes constituting a display device, and for conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of light-emitting elements.

[0151] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0152] 3A illustrates an example in which two light-emitting units 112 are stacked, but one embodiment of the present invention is not limited to this. Fig. 4A is a cross-sectional view illustrating an example of a configuration between dashed dotted lines X1-X2 in Fig. 1 when three light-emitting units 112 are stacked, and Fig. 4B is a cross-sectional view illustrating an example of a configuration between dashed dotted lines Y1-Y2 in Fig. 1.

[0153] 4A , the light-emitting element 130 includes a pixel electrode 111 on a layer 101 including a transistor, a light-emitting unit 112_1 on the pixel electrode 111, an intermediate layer 113_1 on the light-emitting unit 112_1, a light-emitting unit 112_2 on the intermediate layer 113_1, an intermediate layer 113_2 on the light-emitting unit 112_2, a light-emitting unit 112_3 on the intermediate layer 113_2, a common layer 114 on the light-emitting unit 112_3, and a common electrode 115 on the common layer 114. In the example shown in FIG. 4A , three light-emitting units 112 are stacked, which can be referred to as a three-tiered tandem structure. Here, the light-emitting units 112_1 to 112_3 and the intermediate layers 113_1 and 113_2 can be collectively referred to as layer 103b.

[0154] 4C is a cross-sectional view showing a detailed configuration example of the layer 103b. The light-emitting unit 112_3 includes, for example, a layer 182 on the intermediate layer 113_2, a light-emitting layer 183_3 on the layer 182, and a layer 184 on the light-emitting layer 183_3.

[0155] The light-emitting layers 183_1 to 183_3 can emit, for example, red light, green light, or blue light, respectively. For example, the light-emitting layer 183_1 can emit red light, the light-emitting layer 183_2 can emit green light, and the light-emitting layer 183_3 can emit blue light. Alternatively, the light-emitting layer 183_1 can emit blue light, the light-emitting layer 183_2 can emit yellow light, yellow-green light, or green light, and the light-emitting layer 183_3 can emit blue light. Alternatively, the light-emitting layer 183_1 can emit blue light, the light-emitting layer 183_2 can emit red light and yellow, yellow-green, or green light, and the light-emitting layer 183_3 can emit blue light.

[0156] The light emitting element 130 may have a structure in which four or more light emitting units 112 are stacked. That is, the light emitting element 130 may have a tandem structure of four or more stages.

[0157] In this way, by increasing the number of stacked light-emitting units 112, the luminance obtained from the light-emitting element 130 with the same amount of current can be increased in accordance with the number of stacked layers. Furthermore, by increasing the number of stacked light-emitting units 112, the current required to obtain the same luminance can be reduced, and therefore the power consumption of the light-emitting element 130 can be reduced in accordance with the number of stacked layers.

[0158] 5A is a cross-sectional view showing an example of the configuration between dashed dotted lines X1-X2 in FIG. 1 , and FIG. 5B is a cross-sectional view showing an example of the configuration between dashed dotted lines Y1-Y2 in FIG. 5A and FIG. 5B are modified versions of the configuration shown in FIG. 3A and FIG. 3B , differing in that the sidewall 121 has a single-layer structure. In the configurations shown in FIG. 5A and FIG. 5B , the sidewall 121 can be formed, for example, using the same material as the sidewall 121a and by the same method as the sidewall 121a. For example, the sidewall 121 shown in FIG. 5A and FIG. 5B can be formed using an aluminum oxide film formed by an ALD method.

[0159] 5A and 5B , the manufacturing process of the side wall 121 can be simplified, and the number of manufacturing processes for the display device 100 can be reduced. This allows the display device 100 to be manufactured at low cost and with a high yield. Therefore, the price of the display device 100 can be reduced.

[0160] Fig. 6A is a cross-sectional view showing an example of the configuration between dashed dotted lines X1-X2 in Fig. 1, and Fig. 6B is a cross-sectional view showing an example of the configuration between dashed dotted lines Y1-Y2 in Fig. 1. Figs. 6A and 6B are modified examples of the configuration shown in Figs. 3A and 3B, and differ from display device 100 shown in Figs. 3A and 3B in that light-emitting element 130 has layer 114a instead of common layer 114.

[0161] The layer 114a may include, for example, an electron injection layer, similar to the common layer 114. When the pixel electrode 111 functions as a cathode and the common electrode 115 functions as an anode, the layer 114a may include, for example, a hole injection layer.

[0162] The layer 114a is formed in an island shape for each light emitting element 130, similar to the pixel electrode 111, the light emitting unit 112, and the intermediate layer 113. In other words, the layer 114a is provided separately for each light emitting element 130.

[0163] 7A is a cross-sectional view showing an example of the configuration between dashed dotted lines X1-X2 in FIG. 1 , and FIG. 7B is a cross-sectional view showing an example of the configuration between dashed dotted lines Y1-Y2 in FIG. 1 . FIGS. 7A and 7B are modified versions of the configuration shown in FIGS. 3A and 3B , showing an example in which no gap 134 is formed between adjacent light-emitting elements 130, and a common layer 114 is filled in. Note that in addition to the common layer 114, a common electrode 115 may be filled in between adjacent light-emitting elements 130. Furthermore, a protective layer 131 may be filled in. When the distance between adjacent light-emitting elements 130 is long, for example, the gap 134 may not be formed as shown in FIG. 7A .

[0164] 7A , even if the common layer 114 or the like is filled between adjacent light-emitting elements 130, the display device 100 has the sidewalls 121, and therefore the common layer 114 can be prevented from coming into contact with any of the side surfaces of the pixel electrodes 111, the light-emitting units 112, and the intermediate layer 113. Therefore, even if the common layer 114 or the like is filled between adjacent light-emitting elements 130, short-circuiting of the light-emitting elements 130 can be prevented.

[0165] 1 illustrates an example in which the pixel 110 includes three subpixels, ie, the subpixel 110a, the subpixel 110b, and the subpixel 110c, but one embodiment of the present invention is not limited to this.

[0166] 8 is composed of four subpixels: subpixel 110a, subpixel 110b, subpixel 110c, and subpixel 110d. The subpixels 110a, 110b, 110c, and 110d may be subpixels of different colors. For example, the subpixels 110a, 110b, and 110c may be red, green, and blue subpixels, respectively, and the subpixel 110d may be a white subpixel.

[0167] 8 shows an example in which subpixels are arranged in two rows and three columns within one pixel 110. The pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and one subpixel (subpixel 110d) in the bottom row (second row). In other words, the pixel 110 has the subpixel 110a in the left column (first column), the subpixel 110b in the center column (second column), the subpixel 110c in the right column (third column), and further has the subpixels 110d across these three columns.

[0168] Fig. 9A is a cross-sectional view showing an example of the configuration between dashed dotted lines X3-X4 in Fig. 8. Fig. 9B is a cross-sectional view showing an example of the configuration between dashed dotted lines Y3-Y4 in Fig. 8, and is a cross-sectional view showing an example of the configuration of connection portion 140.

[0169] When the light-emitting element 130 has a function of emitting white light, the sub-pixel not provided with the colored layer 133 can be a white sub-pixel.

[0170] 10A to 10F are top views showing configuration examples of a pixel 110 having subpixels 110a, 110b, 110c, and 110d, which are modifications of the pixel 110 shown in FIG.

[0171] The pixels 110 shown in Figures 10A to 10C are arranged in a stripe pattern, while the pixels 110 shown in Figures 10D to 10F are arranged in a matrix pattern.

[0172] Fig. 10A shows an example in which each subpixel has a rectangular top surface shape, Fig. 10B shows an example in which each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, Fig. 10C shows an example in which each subpixel has an elliptical top surface shape, Fig. 10D shows an example in which each subpixel has a square top surface shape, Fig. 10E shows an example in which each subpixel has a substantially square top surface shape with rounded corners, and Fig. 10F shows an example in which each subpixel has a circular top surface shape.

[0173] [Example of a Method for Manufacturing a Display Device] Next, a description will be given of an example of a method for manufacturing the display device 100. Specifically, a description will be given of an example of a method for manufacturing the display device 100 shown in FIGS.

[0174] 11A to 11E, 12A to 12E, 13A, and 13B are cross-sectional views showing an example of a method for manufacturing the display device 100, and show a cross-sectional view between dashed dotted lines X1-X2 and a cross-sectional view between Y1-Y2 in FIG. 1 side by side.

[0175] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using a sputtering method, a CVD method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. One type of thermal CVD method is a metal organic CVD (MOCVD) method.

[0176] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) constituting 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.

[0177] In particular, vacuum processes such as vapor deposition, and solution processes such as spin coating and inkjet printing can be used to fabricate light-emitting elements. Vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, and chemical vapor deposition (CVD). In particular, functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, etc.) included in the light-emitting unit can be formed by methods such as vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet printing, screen (stencil printing), offset (lithographic printing), flexography (relief printing), gravure, microcontact printing, etc.), etc.

[0178] 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, the island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0179] 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.

[0180] 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, ArF laser light, etc. Exposure can also be performed by immersion exposure technology. Extreme ultraviolet light (EUV) or X-rays can also be used as the light used for exposure. An electron beam can also be used instead of the light used for exposure. 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.

[0181] The thin film can be processed by dry etching, wet etching, sandblasting, or the like.

[0182] To manufacture the display device 100, first, a layer 101 including a transistor is formed. As described above, the outermost surface of the layer 101 including a transistor can be an insulating layer. Subsequently, a conductive film 111A, which will later become a pixel electrode 111 and a connection electrode 111C, is formed on the layer 101 including a transistor.

[0183] Next, a layer 112_1A to become the light-emitting unit 112_1 is formed on the conductive film 111A. Specifically, a film to become the layer 181, a film to become the layer 182, a light-emitting film to become the light-emitting layer 183_1, and a film to become the layer 184 are formed in this order. Then, an intermediate film 113A to become the intermediate layer 113 is formed on the layer 112_1A.

[0184] Subsequently, a layer 112_2A to become the light-emitting unit 112_2 is formed on the intermediate film 113A. Specifically, a film to become the layer 182, a light-emitting film to become the light-emitting layer 183_2, and a film to become the layer 184 are formed in this order.

[0185] The films included in the layer 112_1A, the intermediate film 113A, and the layer 112_2A can be formed by, for example, an evaporation method, a sputtering method, an ink-jet method, or the like. Note that the present invention is not limited to these methods, and any of the above-described film formation methods can be used as appropriate.

[0186] It is preferable that the layer 112_1A, the intermediate film 113A, and the layer 112_2A are not provided in the connection portion 140. For example, when the films included in the layer 112_1A, the intermediate film 113A, and the layer 112_2A are formed by evaporation (or sputtering), it is preferable to use a shielding mask so that these films are not formed in the connection portion 140.

[0187] Subsequently, a sacrificial film 141 is formed on the layer 112_2 A. The sacrificial film 141 is also provided in the connection portion 140.

[0188] The sacrificial film 141 can be a film that is highly resistant to etching of the films included in the layer 112_2A, the intermediate film 113A, and the layer 112_1A, i.e., a film with a high etching selectivity. Furthermore, the sacrificial film 141 can be a film that has a high etching selectivity with respect to a protective film such as a protective film 143 described later. Furthermore, the sacrificial film 141 can be a film that can be removed by wet etching, which causes little damage to the films included in the layer 112_2A, the intermediate film 113A, and the layer 112_1A.

[0189] The sacrificial film 141 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. The sacrificial film 141 may be formed by various film formation methods such as a sputtering method, a vapor deposition method, a CVD method, or an ALD method.

[0190] For example, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metal materials can be used as the sacrificial film 141. In particular, it is preferable to use a low-melting-point material such as aluminum or silver.

[0191] Furthermore, a metal oxide such as indium gallium zinc oxide (In—Ga—Zn oxide, also referred to as IGZO) can be used as the sacrificial film 141. Further, indium oxide, indium zinc oxide (In—Zn oxide), indium tin oxide (In—Sn oxide), indium titanium oxide (In—Ti oxide), indium tin zinc oxide (In—Sn—Zn oxide), indium titanium zinc oxide (In—Ti—Zn oxide), indium gallium tin zinc oxide (In—Ga—Sn—Zn oxide), etc. can also be used. Alternatively, indium tin oxide containing silicon can also be used.

[0192] The present invention can also be applied to a case where 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) is used instead of the gallium. In particular, it is preferable that M is one or more elements selected from gallium, aluminum, and yttrium.

[0193] The sacrificial film 141 can be made of an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide.

[0194] Furthermore, it is preferable to use a material that can be dissolved in a chemically stable solvent for the sacrificial film 141. In particular, a material that can be dissolved in water or alcohol can be suitably used for the sacrificial film 141. When forming the sacrificial film 141, it is preferable to apply the sacrificial film 141 by a wet film formation method in a state where the sacrificial film 141 is dissolved in a solvent such as water or alcohol, and then perform heat treatment to evaporate the solvent. At this time, by performing heat treatment under a reduced pressure atmosphere, the solvent can be removed at a low temperature in a short time, which is preferable because thermal damage to the layer 112_2A, the intermediate film 113A, and the layer 112_1A can be reduced.

[0195] Wet film formation methods that can be used to form the sacrificial film 141 include spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, knife coating, etc.

[0196] The sacrificial film 141 can be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0197] Subsequently, a protective film 143 is formed on the sacrificial film 141 (FIG. 11A).

[0198] The protective film 143 is a film that is used as a mask when etching the sacrificial film 141 later. Furthermore, when etching the protective film 143 later, the sacrificial film 141 is exposed. Therefore, a combination of films that have a large etching selectivity between the sacrificial film 141 and the protective film 143 is selected. Therefore, a film that can be used for the protective film 143 can be selected depending on the etching conditions for the sacrificial film 141 and the etching conditions for the protective film 143.

[0199] For example, when dry etching using a gas containing fluorine (also referred to as a fluorine-based gas) is used to etch the protective film 143, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, an alloy containing molybdenum and tungsten, or the like can be used for the protective film 143. Here, metal oxide films such as IGZO and ITO can be used as films that can have a large etching selectivity (i.e., can slow down the etching rate) compared to dry etching using the fluorine-based gas.

[0200] However, the protective film 143 is not limited to this, and can be selected from various materials depending on the etching conditions of the sacrificial film 141 and the etching conditions of the protective film 143. For example, it can be selected from the films that can be used for the sacrificial film 141.

[0201] Furthermore, for example, a nitride film can be used as the protective film 143. Specifically, nitrides such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, and germanium nitride can also be used.

[0202] Alternatively, an oxide film can be used as the protective film 143. Typically, an oxide film or an oxynitride film such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, or hafnium oxynitride can be used.

[0203] Subsequently, a resist mask 145 is formed on the protective film 143 (FIG. 11B).

[0204] The resist mask 145 can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0205] Here, when the resist mask 145 is formed on the sacrificial film 141 without forming the protective film 143, if defects such as pinholes exist in the sacrificial film 141, a film of the layer 112_2A that will later become the layer 184 may be dissolved by a solvent of the resist material. By using the protective film 143, it is possible to prevent such problems from occurring.

[0206] When the sacrificial film 141 is made of a film that is less likely to have defects such as pinholes, the resist mask 145 may be formed directly on the sacrificial film 141 without using the protective film 143 .

[0207] Subsequently, a part of the protective film 143 that is not covered by the resist mask 145 is removed by etching to form a protective layer 149. At this time, the protective layer 149 is also formed on the connection portion 140.

[0208] When etching the protective film 143, it is preferable to use etching conditions with a high selectivity so that the sacrificial film 141 is not removed by the etching. The protective film 143 can be etched by wet etching or dry etching, but by using dry etching, it is possible to prevent the pattern of the protective film 143 from shrinking.

[0209] Subsequently, the resist mask 145 is removed (FIG. 11C).

[0210] The resist mask 145 can be removed by wet etching or dry etching. In particular, it is preferable to remove the resist mask 145 by dry etching (also called plasma ashing) using oxygen gas as an etching gas.

[0211] At this time, the resist mask 145 is removed in a state in which the sacrificial film 141 is provided over the layer 112_2A, and therefore influence on the layer 112_2A, the intermediate film 113A, and the layer 112_1A is suppressed. In particular, if the layer 112_1A and the layer 112_2A are exposed to oxygen, the electrical characteristics may be adversely affected. Therefore, this is preferable when etching using oxygen gas, such as plasma ashing, is performed.

[0212] Next, using the protective layer 149 as a mask, a portion of the sacrificial film 141 that is not covered by the protective layer 149 is removed by etching to form a sacrificial layer 147 (FIG. 11D). At the same time, the sacrificial layer 147 is also formed on the connecting portion 140.

[0213] The sacrificial film 141 can be etched by wet etching or dry etching, but dry etching is preferable because it can prevent the pattern from shrinking.

[0214] Next, using the sacrificial layer 147 as a mask, parts of the layer 112_2A, the intermediate film 113A, the layer 112_1A, and the conductive film 111A that are not covered with the sacrificial layer 147 are removed by etching to form the light-emitting unit 112_2, the intermediate layer 113, the light-emitting unit 112_1, the pixel electrode 111, and the connection electrode 111C (FIG. 11E). Note that the protective layer 149 may be removed by etching simultaneously with or before the etching of the layer 112_2A, the intermediate film 113A, the layer 112_1A, and the conductive film 111A.

[0215] The layer 112_2A, the intermediate film 113A, the layer 112_1A, and the conductive film 111A are preferably etched by dry etching using an etching gas that does not contain oxygen as a main component. This can suppress deterioration of the layer 112_2A, the intermediate film 113A, the layer 112_1A, and the conductive film 111A, thereby achieving a highly reliable display device. Examples of the etching gas that does not contain oxygen as a main component include CF ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ , H ２ Alternatively, a noble gas such as He may be used. A mixed gas of the above gas and a dilution gas that does not contain oxygen may be used as the etching gas.

[0216] When the conductive film 111A is etched, a part of the transistor-containing layer 101 (specifically, the insulating layer located at the outermost surface) may be etched, forming a recess. In the following description, a case where a recess is provided in the transistor-containing layer 101 will be described as an example, but the recess may not be provided.

[0217] Subsequently, an insulating film 121A, which will later become the sidewall 121a, is formed so as to cover the pixel electrode 111, the connection electrode 111C, the light-emitting unit 112_1, the intermediate layer 113, the light-emitting unit 112_2, the sacrificial layer 147, and the protective layer 149. Next, an insulating film 121B, which will later become the sidewall 121b, is formed on the insulating film 121A ( FIG. 12A ).

[0218] The insulating film 121A is preferably formed by a method that causes little damage to the light-emitting unit 112. The insulating films 121A and 121B are formed at a temperature lower than the heat resistance temperature of the light-emitting unit 112. For example, an aluminum oxide film can be formed as the insulating film 121A by an ALD method. The ALD method is preferable because it allows the formation of a film with high coverage. For example, a silicon oxynitride film or a silicon nitride film can be formed as the insulating film 121B by a PECVD method or a sputtering method.

[0219] Next, the insulating films 121B and 121A are etched to form sidewalls 121b and 121a ( FIG. 12B ). The sidewalls 121a are formed to cover at least a portion of the side surfaces of the pixel electrode 111 and the connection electrode 111C. This prevents the common layer 114 or common electrode 115, which will be formed later, from contacting the pixel electrode 111 or the connection electrode 111C, thereby preventing the light-emitting element from shorting out. Furthermore, the sidewalls 121a are preferably formed to cover at least a portion of the side surfaces of the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2. This prevents the common layer 114 or common electrode 115, which will be formed later, from contacting the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2, thereby preventing the light-emitting element from shorting out. Furthermore, damage to the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2 in subsequent steps can be suppressed.

[0220] In particular, if a recess is provided in a part of the layer 101 including the transistor (specifically, the insulating layer located on the outermost surface), it is possible to cover the entire side surface of the pixel electrode 111 and the entire side surface of the connection electrode 111C with the sidewall 121a, which is preferable.

[0221] Here, the side wall 121b is formed so as to cover at least a part of the side surface of the side wall 121a.

[0222] The insulating films 121A and 121B are preferably etched by dry etching. The insulating films 121A and 121B are preferably etched by anisotropic etching. Here, the insulating films 121A and 121B can be etched using an etching gas that can be used to etch the sacrificial film 141. Furthermore, when etching the insulating films 121A and 121B, the light-emitting unit 112_2 is not exposed, so the range of etching methods is wider than when etching the sacrificial film 141. Specifically, when etching the insulating films 121A and 121B, a gas containing oxygen may be used as an etching gas.

[0223] Next, the sacrificial layer 147 and the protective layer 149 are removed (FIG. 12C), thereby exposing the light-emitting unit 112_2 and the connection electrode 111C.

[0224] Next, the common layer 114 is formed on the sidewall 121b and the light-emitting unit 112_2 (FIG. 12D). As a result, a gap 134 may be formed in the region between the sidewalls 121b and in the recess of the transistor-including layer 101. Here, the common layer 114 is not provided on the connection electrode 111C, and the connection electrode 111C remains exposed. As described above, the common layer 114 functions as either an electron injection layer or a hole injection layer.

[0225] The common layer 114 can be formed by a method such as a vapor deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0226] The common layer 114 is provided to cover the top surface of the light-emitting unit 112_2 and at least a part of the top surface and side surface of the sidewall 121. Here, if the common layer 114 has high conductivity, contact between the pixel electrode 111 and the common layer 114 may cause a short circuit in the light-emitting element. However, in the display device of one embodiment of the present invention, the sidewall 121 covers the side surfaces of the pixel electrode 111, the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2. This prevents the highly conductive common layer 114 from coming into contact with these surfaces, thereby preventing a short circuit in the light-emitting element. This can improve the reliability of the light-emitting element.

[0227] Subsequently, a common electrode 115 is formed on the common layer 114 and the connection electrode 111C (FIG. 12E), thereby forming the light-emitting element 130. The common electrode 115 can be formed by, for example, sputtering or vacuum deposition.

[0228] Next, a protective layer 131 is formed on the common electrode 115, and a protective layer 132 is formed on the protective layer 131 ( FIG. 13A ). Examples of methods for forming the protective layer 131 and the protective layer 132 include vacuum deposition, sputtering, CVD, and ALD. The protective layer 131 and the protective layer 132 may be films formed using different film formation methods. Furthermore, the protective layer 131 and the protective layer 132 may each have a single-layer structure or a multilayer structure.

[0229] Next, colored layers 133a, 133b, and 133c are formed on the protective layer 132 so as to have regions overlapping with the light-emitting units 112_1 and 112_2 ( FIG. 13B ). The colored layers 133a, 133b, and 133c can be formed at desired positions by an inkjet method, a photolithography method, or the like. Specifically, a different colored layer 133 (colored layer 133a, colored layer 133b, or colored layer 133c) can be formed for each light-emitting element 130.

[0230] Thereafter, the substrate 120 is attached onto the colored layer 133 using the resin layer 119, whereby the display device 100 shown in FIGS. 3A and 3B can be manufactured.

[0231] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped light-emitting unit having the light-emitting layer is not formed by a metal mask pattern, but is formed by etching after forming the light-emitting unit on the entire surface. Therefore, the island-shaped light-emitting unit can be formed with a uniform thickness. Furthermore, a high-definition display device or a display device with a high aperture ratio can be realized.

[0232] A display device according to one embodiment of the present invention has a tandem-structured light-emitting element. The pixel electrode, light-emitting layer, carrier transport layer, and intermediate layer of the light-emitting element are covered with sidewalls on their respective sides. In a manufacturing process of the display device, the light-emitting unit of the light-emitting element is etched while the light-emitting layer and the carrier transport layer are stacked. Therefore, the display device has a structure in which damage to the light-emitting layer is reduced. Furthermore, the sidewalls prevent the pixel electrode from contacting the carrier injection layer or the common electrode, thereby preventing the light-emitting element from shorting out.

[0233] This embodiment mode can be combined with other embodiment modes as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0234] Embodiment 2 In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0235] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0236] The display device of the present embodiment can be a high-definition display device, and can therefore be used as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays and AR glasses-type devices.

[0237] 14A shows a perspective view of a display module 280. The display module 280 includes the display device 100 and an FPC 290.

[0238] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display portion 281. The display portion 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 portion 284 (described later) can be viewed.

[0239] 14B is a perspective view schematically illustrating the configuration on the substrate 291 side. 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 on the substrate 291. A terminal portion 285 for connecting to the FPC 290 is provided in a portion of the substrate 291 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.

[0240] The pixel unit 284 has a plurality of pixels 110 arranged periodically. An enlarged view of one pixel 110 is shown on the right side of Fig. 14B. The pixel 110 has subpixels 110a, 110b, and 110c. The pixel 110 may also have a subpixel 110d. The subpixels may be arranged in a stripe array as shown in Fig. 14B. Various subpixel arrangement methods, such as a delta array or a pentile array, may also be applied.

[0241] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0242] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting elements included in one pixel 110. 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 capacitor for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a video signal is input to either the source or the drain. This realizes an active matrix display device.

[0243] 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.

[0244] The semiconductor layer of the transistor preferably contains metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably uses a transistor using metal oxide in a channel formation region (hereinafter referred to as an OS transistor). Alternatively, the semiconductor layer of the transistor preferably contains silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0245] The semiconductor layer preferably contains, for example, indium, M (wherein M is one or more elements selected from gallium, aluminum, silicon, 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.

[0246] 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.

[0247] 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 a composition in which In:M:Zn=1:1:1 or thereabouts, a composition in which In:M:Zn=1:1:1.2 or thereabouts, a composition in which In:M:Zn=2:1:3 or thereabouts, a composition in which In:M:Zn=3:1:2 or thereabouts, a composition in which In:M:Zn=4:2:3 or thereabouts, a composition in which In:M:Zn=4:2:4.1 or thereabouts, a composition in which In:M:Zn=5:1:3 or thereabouts, a composition in which In:M:Zn=5:1:6 or thereabouts, a composition in which In:M:Zn=5:1:7 or thereabouts, a composition in which In:M:Zn=5:1:8 or thereabouts, a composition in which In:M:Zn=6:1:6 or thereabouts, and a composition in which In:M:Zn=5:2:5 or thereabouts. The term "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0248] For example, when describing a composition having 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 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Furthermore, when describing a composition having 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 more than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Furthermore, when describing a composition having 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 more than 0.1 and 2 or less, and the atomic ratio of Zn is more than 0.1 and 2 or less.

[0249] The transistors included in the circuit portion 282 and the transistors included in the pixel circuit portion 283 may have the same structure or different structures. The transistors included in the circuit portion 282 may all have the same structure or may have two or more types. Similarly, the transistors included in the pixel circuit portion 283 may all have the same structure or may have two or more types.

[0250] The circuit portion 282 includes a circuit for driving each pixel circuit 283 a of the pixel circuit portion 283. For example, the circuit portion 282 preferably includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0251] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. An IC (integrated circuit) may be mounted on the FPC 290.

[0252] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are 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 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 110 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 110 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 20,000 ppi or less, or 30,000 ppi or less.

[0253] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-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 even when the display unit is enlarged with 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 with relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0254] 15 is a cross-sectional view showing an example of the configuration of the display device 100 A. The display device 100 A shown in FIG. 15 includes, between a substrate 451 and a substrate 120, a transistor 201, a transistor 205, a light-emitting element 130, a coloring layer 133 a, a coloring layer 133 b, and a coloring layer 133 c.

[0255] The light-emitting element exemplified in Embodiment 1 can be applied to the light-emitting element 130 .

[0256] The transistor 201 and the transistor 205 are both formed over a substrate 451. These transistors can be manufactured using the same material and through the same process.

[0257] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 451 in this order. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. A part of the insulating layer 213 functions as a gate insulating layer of each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0258] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0259] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 213, and 215. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0260] Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 100A. This can prevent impurities from entering through the edge of the display device 100A via the organic insulating film. Alternatively, the organic insulating film may be formed so that the edge of the organic insulating film is located inside the edge of the display device 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0261] An organic insulating film is suitable for the insulating layer 214 that functions as a planarizing layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0262] 15 , an opening is formed in the insulating layer 214. This makes it possible to prevent impurities from entering the light emitting element 130 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. This makes it possible to improve the reliability of the display device 100A.

[0263] The transistor 201 and the transistor 205 each include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0264] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0265] The transistor 201 and the transistor 205 have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and the same signal may be supplied to drive the transistor. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0266] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than a single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0267] The semiconductor layer of the transistor preferably contains metal oxide. That is, the display device of this embodiment preferably uses a transistor in which a channel formation region is formed using metal oxide. Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0268] The semiconductor layer preferably contains, for example, indium, M (wherein M is one or more elements selected from gallium, aluminum, silicon, 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.

[0269] 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.

[0270] 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 a composition in which In:M:Zn=1:1:1 or thereabouts, a composition in which In:M:Zn=1:1:1.2 or thereabouts, a composition in which In:M:Zn=2:1:3 or thereabouts, a composition in which In:M:Zn=3:1:2 or thereabouts, a composition in which In:M:Zn=4:2:3 or thereabouts, a composition in which In:M:Zn=4:2:4.1 or thereabouts, a composition in which In:M:Zn=5:1:3 or thereabouts, a composition in which In:M:Zn=5:1:6 or thereabouts, a composition in which In:M:Zn=5:1:7 or thereabouts, a composition in which In:M:Zn=5:1:8 or thereabouts, a composition in which In:M:Zn=6:1:6 or thereabouts, and a composition in which In:M:Zn=5:2:5 or thereabouts. The term "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0271] For example, when describing a composition having 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 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Furthermore, when describing a composition having 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 more than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Furthermore, when describing a composition having 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 more than 0.1 and 2 or less, and the atomic ratio of Zn is more than 0.1 and 2 or less.

[0272] A connection portion 204 is provided in a region of the substrate 451 that does not overlap with the substrate 120. In the connection portion 204, a wiring 465 is electrically connected to an FPC 472 via a conductive layer 466 and a connection layer 242. The conductive layer 466 can be formed in the same process as the pixel electrode. The conductive layer 466 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 472 to be electrically connected via the connection layer 242.

[0273] Various optical members can be disposed on the outside of the substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. In addition, an antistatic film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses scratches caused by use, an impact absorbing layer, etc. may also be disposed on the outside of the substrate 120.

[0274] By providing the protective layer 131 that covers the light emitting element, impurities such as water can be prevented from entering the light emitting element, and the reliability of the light emitting element can be improved.

[0275] In a region 228 near the edge of the display device 100A, it is preferable that the insulating layer 215 and the protective layer 131 contact each other through the opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 131 contact each other. This makes it possible to prevent impurities from entering the light-emitting element 130 from the outside through the organic insulating film. Therefore, it is possible to improve the reliability of the display device 100A.

[0276] The substrate 451 and the substrate 120 can each be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting element is extracted. Using a flexible material for the substrate 451 and the substrate 120 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used for the substrate 451 or the substrate 120.

[0277] The substrate 451 and the substrate 120 may each be made of a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of the substrate 451 and the substrate 120 may be made of glass having a thickness sufficient to provide flexibility.

[0278] The adhesive layer can be made of various curable adhesives, such as photocurable adhesives (e.g., ultraviolet curable), reactive curable adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Adhesive sheets, etc., may also be used.

[0279] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0280] In the display device 100A, the colored layers 133a, 133b, and 133c are provided between the light-emitting element 130 and the substrate 120. As described above, the transistors are formed on the substrate 451. As described above, the display device 100A can be a top-emission display device. Therefore, in the display device 100A, the substrate 451 can be a non-light-transmitting substrate.

[0281] [Display Device 100B] Fig. 16 is a cross-sectional view showing an example of the configuration of the display device 100B. The display device 100B is a modified example of the display device 100A, and differs from the display device 100A in that the colored layers 133a, 133b, and 133c are provided between the light-emitting element 130 and the substrate 451. In other words, the display device 100B can be a bottom-emission display device. Therefore, in the display device 100B, the substrate 120 can be a substrate that does not have light-transmitting properties.

[0282] [Display Device 100C] A display device 100C shown in FIG. 17 includes a substrate 301, a light-emitting element 130, a capacitor 240, and a transistor 310.

[0283] 14A and 14B. The stacked structure from the substrate 301 to the insulating layer 255 corresponds to the layer 101 including the transistor in Embodiment 1.

[0284] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0285] An element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0286] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0287] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0288] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0289] An insulating layer 255 is provided to cover the capacitor 240, and the light emitting element 130 and the like are provided on the insulating layer 255. A protective layer 131 is provided on each of the light emitting elements 130. A protective layer 132 is provided on the protective layer 131, and a substrate 120 is bonded to the protective layer 132 with a resin layer 119. For details of the components from the light emitting element to the substrate 120, refer to Embodiment 1. The substrate 120 corresponds to the substrate 292 in FIG. 14A .

[0290] The pixel electrode of the light-emitting element is electrically connected to one of the source or drain of the transistor 310 by an insulating layer 255, a plug 256 embedded in the insulating layer 243, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261.

[0291] 18 is different from the display device 100C mainly in the configuration of the transistors. Note that descriptions of parts that are the same as those of the display device 100C may be omitted.

[0292] The transistor 320 is a transistor (OS transistor) in which a metal oxide is used for a semiconductor layer in which a channel is formed.

[0293] The transistor 320 includes a semiconductor layer 321 , an insulating layer 323 , a conductive layer 324 , a pair of conductive layers 325 , an insulating layer 326 , and a conductive layer 327 .

[0294] 14A and 14B . The stacked structure from the substrate 331 to the insulating layer 255 corresponds to the layer 101 including the transistor in Embodiment 1. The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0295] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 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.

[0296] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 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 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0297] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide film having semiconductor properties.

[0298] The pair of conductive layers 325 are provided over and in contact with the semiconductor layer 321 and function as a source electrode and a drain electrode.

[0299] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like to the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0300] Openings reaching the semiconductor layer 321 are provided in the insulating layer 328 and the insulating layer 264. Inside the openings, an insulating layer 323 and a conductive layer 324 are buried, which are in contact with side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and an upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0301] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0302] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0303] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided to be embedded in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328. Here, the plug 274 preferably includes a conductive layer 274a covering the side surfaces of the openings of the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and part of the top surface of the conductive layer 325, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. In this case, the conductive layer 274a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0304] Additionally, the layer 101 including the transistor may include various inorganic insulating films. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Also, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0305] The configuration of the display device 100D from the insulating layer 254 to the substrate 120 is the same as that of the display device 100C.

[0306] 19 has a stacked structure of a transistor 310 in which a channel is formed in a substrate 301 and a transistor 320 in which a channel is formed and a semiconductor layer containing metal oxide. Note that descriptions of parts similar to those of the display device 100C and the display device 100D may be omitted.

[0307] An insulating layer 261 is provided to cover the transistor 310, 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 layers 251 and 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and the transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0308] The transistor 320 can be used as a transistor that forms a pixel circuit. The transistor 310 can be used as a transistor that forms a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) that drives the pixel circuit. The transistors 310 and 320 can be used as transistors that form various circuits such as an arithmetic circuit or a memory circuit.

[0309] With this configuration, not only pixel circuits but also driver circuits and the like can be formed directly under the light-emitting elements, making it possible to miniaturize the display device compared to when driver circuits are provided around the periphery of the display area.

[0310] This embodiment mode can be combined with other embodiment modes as appropriate.

[0311] Embodiment 3 In this embodiment, a metal oxide that can be used for the OS transistor described in the above embodiment will be described.

[0312] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. It is also preferable that it contains aluminum, gallium, yttrium, tin, or the like in addition to these. It may also contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, and the like.

[0313] The metal oxide can be formed by a sputtering method, a CVD method such as an MOCVD method, or an ALD method.

[0314] <Classification of Crystal Structure> Examples of the crystal structure of an oxide semiconductor include amorphous (including completely amorphous), c-axis-aligned crystalline line (CAAC), nanocrystalline line (nc), cloud-aligned composite (CAC), single crystal, and polycrystalline.

[0315] The crystalline structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using an XRD spectrum obtained by a GIXD (Grazing-Incident XRD) measurement. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0316] For example, in the case of a quartz glass substrate, the shape of the peak in the XRD spectrum is almost symmetrical. On the other hand, in the case of an IGZO film having a crystalline structure, the shape of the peak in the XRD spectrum is asymmetrical. The asymmetrical shape of the peak in the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the shape of the peak in the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0317] The crystalline structure of the film or substrate can be evaluated by a diffraction pattern (also referred to as a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, and it can be confirmed that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film formed at room temperature, rather than a halo. For this reason, it is estimated that the IGZO film formed 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.

[0318] <<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 classified 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, pseudo-amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0319] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0320] [CAAC-OS] A CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction refers to the thickness direction of the CAAC-OS film, the normal direction to the surface where the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystalline region is also a region with a uniform lattice arrangement. Furthermore, a CAAC-OS has a region where multiple crystalline regions are connected in the a-b plane direction, and the region may have distortion. Note that distortion refers to a portion where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with another uniform lattice arrangement in a region where multiple crystalline regions are connected. In other words, a CAAC-OS is an oxide semiconductor whose c-axes are aligned and whose orientation is not clearly aligned in the a-b plane direction.

[0321] 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 a single 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 size of the crystalline region may be several tens of nanometers.

[0322] In an In-M-Zn oxide (wherein the element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, and the like), 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 the element 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 the element 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.

[0323] When a CAAC-OS film is subjected to structural analysis using an XRD apparatus, for example, a peak indicating c-axis orientation is detected at or near 2θ = 31° in out-of-plane XRD measurement using θ / 2θ scanning. Note that the position of the peak indicating c-axis orientation (the value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0324] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film, and the spots are observed at positions that are point-symmetric with respect to a spot of an incident electron beam that has passed through the sample (also referred to as a direct spot).

[0325] When a crystalline region is observed from the specific direction, the lattice arrangement in the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. The distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundary can be identified even near the distortion. This indicates that the distortion in the lattice arrangement suppresses the formation of grain boundaries. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed arrangement of oxygen atoms in the a-b plane and the change in interatomic bond distance caused by metal atom substitution.

[0326] Note that a crystal structure in which clear grain boundaries are observed is called polycrystalline. The grain boundaries act as recombination centers, and are likely to trap carriers, resulting in a decrease in the on-state current of a transistor and a decrease in field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. Note that a structure containing Zn is preferable for forming a 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.

[0327] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities, the formation of defects, or the like, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, an oxide semiconductor having a CAAC-OS has stable physical properties. Therefore, an oxide semiconductor having a CAAC-OS is heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of a CAAC-OS in an OS transistor can increase the flexibility of the manufacturing process.

[0328] [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 microcrystals. Note that the size of the microcrystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the microcrystals are also called nanocrystals. Furthermore, the nc-OS does not exhibit regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis 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 apparatus, no peak indicating crystallinity is detected in out-of-plane XRD measurement using θ / 2θ scanning. When an nc-OS film is subjected to electron diffraction (also referred to as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of a nanocrystal (e.g., 50 nm or more), a diffraction pattern resembling a halo pattern is observed. On the other hand, when an nc-OS film is subjected to electron diffraction (also referred to as nanobeam electron diffraction) using an electron beam with a probe diameter close to or smaller than that of a nanocrystal (e.g., 1 nm to 30 nm), an electron diffraction pattern in which multiple spots are observed within a ring-shaped region centered on a direct spot may be obtained.

[0329] [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 the CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and the CAAC-OS.

[0330] <<Structure of Oxide Semiconductor>> Next, the above-described CAC-OS will be described in detail. Note that the CAC-OS relates to a material structure.

[0331] [CAC-OS] CAC-OS is, for example, a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. Note that hereinafter, a state in which one or more metal elements are unevenly distributed in a metal oxide and regions containing the metal elements are mixed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0332] Furthermore, the CAC-OS has a mosaic structure in which a material is separated into a first region and a second region, and the first region is distributed throughout the film (hereinafter also referred to as a cloud structure). That is, the CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0333] 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.

[0334] 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 referred to as a region whose main component is In. The second region can be referred to as a region whose main component is Ga.

[0335] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0336] Furthermore, CAC-OS in In—Ga—Zn oxide refers to a structure in which a mosaic of regions containing Ga as the main component and regions containing In as the main component are randomly arranged in a material composition containing In, Ga, Zn, and O. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0337] The CAC-OS can be formed by sputtering without heating the substrate. When the CAC-OS is formed by sputtering, 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 of oxygen gas relative to the total flow rate of deposition gas during deposition, the more preferable it is. For example, the flow rate of oxygen gas relative 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.

[0338] Furthermore, for example, in the case of CAC-OS in an In—Ga—Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) can confirm 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.

[0339] 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).

[0340] 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.

[0341] Therefore, when a CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (a function of turning on / off). In other words, a CAC-OS has a conductive function in a part of the material and an insulating function in a part of the material, and the entire material functions as a semiconductor. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using a CAC-OS in a transistor, a high on-current (I ｏｎ), high field-effect mobility (μ), and good switching behavior can be achieved.

[0342] Furthermore, a transistor using the CAC-OS has high reliability, and therefore, the CAC-OS is ideal for various semiconductor devices such as display devices.

[0343] Oxide semiconductors have a variety of structures, each of which has 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.

[0344] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0345] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0346] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 １７ cm −３ Below 1 × 10, preferably １５ cm −３ More preferably, 1×10 １３ cm −３ Less than 1×10, more preferably 1×10 １１ cm −３ More preferably, 1×10 １０ cm −３ is less than 1×10 −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.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0351] When an oxide semiconductor contains silicon or carbon, which is one of Group 14 elements, 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 set to 2×10 １８ atoms / cm ３ Below 2 × 10, preferably １７ atoms / cm ３ The following applies.

[0352] Furthermore, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed and carriers are generated in some cases. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 １８ atoms / cm ３ Below 2 × 10, preferably１６ atoms / cm ３ Do the following:

[0353] 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 5×10 １８ atoms / cm ３ Less than 1×10, more preferably 1×10 １８ atoms / cm ３ or less, more preferably 5 × 10 １７ atoms / cm ３ Do the following:

[0354] 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. Hydrogen entering the oxygen vacancy may generate electrons as carriers. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. Therefore, it is preferable to reduce hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor measured by SIMS is 1×10 ２０ atoms / cm ３ less than 1×10 １９ atoms / cm ３ less than 5×10 １８ atoms / cm ３ less than 1×10 １８ atoms / cm ３ Make it less than.

[0355] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0356] This embodiment mode can be combined with other embodiment modes as appropriate.

[0357] Embodiment 4 In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0358] The electronic devices of this embodiment include the display device of one embodiment of the present invention in their display portions. The display device of one embodiment of the present invention can easily achieve high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portions of various electronic devices.

[0359] 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.

[0360] 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 wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices such as head-mounted displays, AR glasses-type devices, and MR devices.

[0361] 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), 4K (3840 × 2160 pixels), or 8K (7680 × 4320 pixels). A resolution of 4K, 8K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 100 ppi or higher, more 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 having either or both of high resolution and high definition, it is possible to further enhance the sense of realism and depth in electronic devices for personal use, such as portable or home use. Furthermore, the screen ratio (aspect ratio) of the display device of one embodiment of the present invention is not particularly limited. For example, the display device can support various screen ratios, such as 1:1 (square), 4:3, 16:9, and 16:10.

[0362] 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).

[0363] 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.

[0364] 20A, 20B, 21A, and 21B, examples of wearable devices that can be worn on the head will be described. These wearable devices have one or both of a function to display AR content and a function to display VR content. Note that these wearable devices may also have a function to display SR or MR content in addition to AR and VR. By having an electronic device have the function to display content such as AR, VR, SR, and MR, it is possible to enhance the user's sense of immersion.

[0365] The electronic device 700A shown in FIG. 20A and the electronic device 700B shown in FIG. 20B each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0366] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device can provide an extremely high-definition display.

[0367] The electronic device 700A and the electronic device 700B can each project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Because the optical member 753 is translucent, the user can see the image displayed in the display area 756 superimposed on a transmitted image visually recognized through the optical member 753. Therefore, the electronic device 700A and the electronic device 700B are each electronic devices capable of AR display.

[0368] Electronic device 700A and electronic device 700B may be provided with a camera capable of capturing an image in front of them as an imaging unit. Furthermore, electronic device 700A and electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to that orientation in display area 756.

[0369] The communication unit has a wireless communication device, and can supply a video signal, etc. Instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential are supplied may be provided.

[0370] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or by wire.

[0371] The housing 721 may be provided with a touch sensor module. The touch sensor module has a function of detecting a touch on the outer surface of the housing 721. The touch sensor module can detect a tap operation or a slide operation by the user and perform various processes. For example, a tap operation can perform a process such as pausing or resuming a video, and a slide operation can perform a process such as fast-forwarding or fast-rewinding. Furthermore, providing a touch sensor module on each of the two housings 721 can expand the range of operations.

[0372] Various touch sensors can be used as the touch sensor module. For example, various types of touch sensors can be used, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, and an optical type. In particular, it is preferable to use a capacitance type or an optical type sensor in the touch sensor module.

[0373] When an optical touch sensor is used, a photoelectric conversion device (also called a photoelectric conversion element) can be used as the light receiving device (also called a light receiving element). The active layer of the photoelectric conversion device can be made of either or both of an inorganic semiconductor and an organic semiconductor.

[0374] The electronic device 800A shown in FIG. 21A and the electronic device 800B shown in FIG. 21B each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0375] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, an electronic device capable of displaying images with extremely high definition can be provided. This allows a user to feel a high sense of immersion.

[0376] The display unit 820 is provided inside the housing 821 at a position that can be viewed through the lens 832. In addition, by displaying different images on the pair of display units 820, it is possible to perform three-dimensional display using parallax.

[0377] The electronic device 800A and the electronic device 800B can be said to be electronic devices for VR. A user wearing the electronic device 800A or the electronic device 800B can view an image displayed on the display unit 820 through the lens 832.

[0378] It is preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the left and right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes. It is also preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the focus by changing the distance between lens 832 and display unit 820.

[0379] The mounting unit 823 allows the user to wear the electronic device 800A or the electronic device 800B on the head. Note that, in Fig. 21A and other figures, the mounting unit 823 is shaped like the temples of glasses (also called joints or temples), but is not limited to this. The mounting unit 823 may be shaped like a helmet or a band, for example, as long as it can be worn by the user.

[0380] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. Furthermore, multiple cameras may be provided to support multiple angles of view, such as telephoto and wide-angle.

[0381] Although an example including the imaging unit 825 is shown here, a distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object may be provided. That is, the imaging unit 825 is one aspect of the detection unit. As the detection unit, for example, an image sensor or a range image sensor such as a LIDAR (Light Detection and Ranging) can be used. By using an image obtained by the camera and an image obtained by the range image sensor, more information can be obtained, enabling more accurate gesture operations.

[0382] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having such a vibration mechanism can be applied to one or more of the display unit 820, the housing 821, and the wearing unit 823. This allows a user to enjoy video and audio simply by wearing the electronic device 800A, without the need for separate audio equipment such as headphones, earphones, or speakers.

[0383] The electronic device 800A and the electronic device 800B may each have an input terminal to which a cable can be connected for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0384] The electronic device of one embodiment of the present invention may have a function of wireless communication with an earphone 750. The earphone 750 includes a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., audio data) from the electronic device through the wireless communication function. For example, the electronic device 700A shown in FIG. 20A has a function of transmitting information to the earphone 750 through the wireless communication function. Furthermore, for example, the electronic device 800A shown in FIG. 21A has a function of transmitting information to the earphone 750 through the wireless communication function.

[0385] The electronic device may also have an earphone unit. Electronic device 700B shown in Fig. 20B has earphone unit 727. For example, earphone unit 727 and the control unit may be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or attachment unit 723.

[0386] Similarly, electronic device 800B shown in Fig. 21B has earphone unit 827. For example, earphone unit 827 and control unit 824 can be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 827 and control unit 824 may be disposed inside housing 821 or wearing unit 823. Furthermore, earphone unit 827 and wearing unit 823 may have magnets. This allows earphone unit 827 to be fixed to wearing unit 823 by magnetic force, which is preferable as it makes storage easier.

[0387] The electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have one or both of an audio input terminal and an audio input mechanism. For example, a sound collection device such as a microphone can be used as the audio input mechanism. By having the audio input mechanism, the electronic device may be endowed with the functionality of a so-called headset.

[0388] As described above, as electronic devices of one embodiment of the present invention, both glasses-type devices (such as the electronic devices 700A and 700B) and goggle-type devices (such as the electronic devices 800A and 800B) are suitable.

[0389] Furthermore, the electronic device of one embodiment of the present invention can transmit information to the earphone by wire or wirelessly.

[0390] The electronic device 6500 shown in FIG. 22A is a portable information terminal that can be used as a smartphone.

[0391] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. The display portion 6502 has a touch panel function.

[0392] The display device of one embodiment of the present invention can be applied to the display portion 6502 .

[0393] FIG. 22B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0394] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0395] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by adhesive layers (not shown).

[0396] In a region outside the display portion 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0397] The flexible display of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. Furthermore, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0398] 23A shows an example of a television set. A television set 7100 has a display portion 7000 built into a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0399] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0400] 23A can be operated using operation switches provided on the housing 7101 and a separate remote control 7111. Alternatively, the display portion 7000 may be provided with a touch sensor, and the television set 7100 may be operated by touching the display portion 7000 with a finger or the like. The remote control 7111 may have a display portion that displays information output from the remote control 7111. Using operation keys or a touch panel provided on the remote control 7111, the channel and volume can be controlled, and an image displayed on the display portion 7000 can be controlled.

[0401] The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from a sender to a receiver) or two-way (between a sender and a receiver, or between receivers, etc.) information communication.

[0402] 23B shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. The housing 7211 includes a display portion 7000.

[0403] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0404] 23C and 23D show an example of digital signage.

[0405] 23C includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0406] 23D shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0407] 23C and 23D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0408] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0409] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used to provide information such as route information or traffic information, the intuitive operation can improve usability.

[0410] 23C and 23D , the digital signage 7300 or the digital signage 7400 is preferably capable of wirelessly linking with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. By operating the information terminal 7311 or the information terminal 7411, the display on the display unit 7000 can be switched.

[0411] Furthermore, the digital signage 7300 or the digital signage 7400 can be made to run a game using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0412] The electronic device shown in Figures 24A to 24F has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to measure force, displacement, position, speed, 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), a microphone 9008, etc.

[0413] The electronic devices shown in Figures 24A to 24F 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 devices are not limited to these, and they may have various other functions. The electronic devices may have multiple display units. Furthermore, the electronic devices 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.

[0414] The electronic device shown in FIGS. 24A to 24F will be described in detail below.

[0415] FIG. 24A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. Note that 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. FIG. 24A 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 radio wave intensity. Alternatively, an icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0416] 24B is a perspective view showing the mobile information terminal 9102. The mobile information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9102 while the mobile information terminal 9102 is placed in a breast pocket of clothes. The user can check the display without taking the mobile information terminal 9102 out of the pocket and decide, for example, whether to answer a call.

[0417] FIG. 24C 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 display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free calling by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and charging with another information terminal through a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0418] 24D to 24F are perspective views showing a foldable mobile information terminal 9201. Also, FIG. 24D is a perspective view of the mobile information terminal 9201 in an unfolded state, FIG. 24F is a perspective view of the mobile information terminal 9201 in a folded state, and FIG. 24E is a perspective view of a state in the process of changing from one of FIGS. 24D and 24F to the other. The mobile information terminal 9201 has excellent portability in a folded state, and excellent display visibility due to a seamless, wide display area in an unfolded state. The display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

[0419] This embodiment mode can be combined with other embodiment modes as appropriate.

[0420] 100: display device, 100A: display device, 100B: display device, 100C: display device, 100D: display device, 100E: display device, 101: layer, 103a: layer, 103b: layer, 110: pixel, 110a: sub-pixel, 110b: sub-pixel, 110c: sub-pixel, 110d: sub-pixel, 111: pixel electrode, 111A: conductive film, 111C: connection electrode, 112: light-emitting unit, 112_1: light-emitting unit, 112_1A: layer, 112_2: light-emitting unit, 112_2A: layer, 112_3: light-emitting unit, 113: intermediate layer, 113_1: intermediate layer, 113_2: intermediate layer, 113 A: intermediate film, 114: common layer, 114a: layer, 115: common electrode, 119: resin layer, 120: substrate, 121: side wall, 121a: side wall, 121A: insulating film, 121b: side wall, 121B: insulating film, 125a: pixel, 125b: pixel, 130: light-emitting element, 131: protective layer, 132: protective layer, 133: colored layer, 133a: colored layer, 133b: colored layer, 133c: colored layer, 134: gap, 140: connecting portion, 141: sacrificial film, 143: protective film, 145: resist mask, 147: sacrificial layer, 149: protective layer, 181: layer, 182: layer, 183: light-emitting layer, 183_1: light-emitting layer , 183_2: light-emitting layer, 183_3: light-emitting layer, 184: layer, 201: transistor, 204: connection portion, 205: transistor, 211: insulating layer, 213: insulating layer, 214: insulating layer, 215: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 228: region, 231: semiconductor layer, 240: capacitance, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274: plug, 274a: conductive layer, 274b: conductive layer, 280: display module, 281: display section, 282: circuit section, 283: pixel circuit section, 283a: pixel circuit, 284: pixel section, 285: terminal section, 286: wiring section, 290: FPC, 291: substrate, 292: substrate, 301: substrate, 310: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer,327: Conductive layer, 328: Insulating layer, 329: Insulating layer, 331: Substrate, 332: Insulating layer, 451: Substrate, 465: Wiring, 466: Conductive layer, 472: FPC, 700A: Electronic device, 700B: Electronic device, 721: Housing, 723: Wearing part, 727: Earphone part, 750: Earphone, 751: Display panel, 753: Optical member, 756: Display area, 757: Frame, 758: Nose pad, 800A: Electronic device, 800B: Electronic device, 820: Display part , 821: Housing, 822: Communication unit, 823: Wearing unit, 824: Control unit, 825: Imaging unit, 827: Earphone unit, 832: Lens, 6500: Electronic device, 6501: Housing, 6502: Display unit, 6503: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective member, 6511: Display panel, 6512: Optical member, 6513: Touch sensor panel, 6515: FPC, 65 16: IC, 6517: printed circuit board, 6518: battery, 7000: display unit, 7100: television device, 7101: housing, 7103: stand, 7111: remote control device, 7200: notebook personal computer, 7211: housing, 7212: keyboard, 7213: pointing device, 7214: external connection port, 7300: digital signage, 7301: housing, 7303: speaker, 7311: information terminal, 74 00: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Housing, 9001: Display unit, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Portable information terminal, 9102: Portable information terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

1. a first light emitting element, a second light emitting element, a first sidewall, a second sidewall, a third sidewall, and a fourth sidewall; the first light-emitting element has a first pixel electrode, a first light-emitting layer on the first pixel electrode, a first intermediate layer on the first light-emitting layer, a second light-emitting layer on the first intermediate layer, and a common electrode on the second light-emitting layer; the second light-emitting element has a second pixel electrode, a third light-emitting layer on the second pixel electrode, a second intermediate layer on the third light-emitting layer, a fourth light-emitting layer on the second intermediate layer, and the common electrode on the fourth light-emitting layer; The first light emitting element and the second light emitting element are adjacent to each other, the first sidewall covers at least a portion of a side surface of the first pixel electrode, side surfaces of the first and second light emitting layers, and a side surface of the first intermediate layer; the second side wall covers at least a portion of a side surface of the first side wall; the third sidewall covers at least a portion of a side surface of the second pixel electrode, side surfaces of the third and fourth light emitting layers, and a side surface of the second intermediate layer; the fourth side wall covers at least a portion of a side surface of the third side wall; The display device has a gap between the second side wall and the fourth side wall.

2. In claim 1, the second side wall covers at least a portion of an upper surface of the first side wall; The fourth side wall covers at least a portion of an upper surface of the third side wall.

3. In claim 1 or 2, A protective layer is provided on the common electrode, a first colored layer is provided on the protective layer so as to have an area overlapping with the first light-emitting layer and the second light-emitting layer; a second colored layer is provided on the protective layer so as to have an area overlapping with the third light-emitting layer and the fourth light-emitting layer; the first colored layer and the second colored layer have a function of transmitting light of different colors; the first light-emitting layer and the third light-emitting layer have a function of emitting light of the same color; The second light-emitting layer and the fourth light-emitting layer have a function of emitting light of the same color.

4. In any one of claims 1 to 3, a common layer between the second and fourth light-emitting layers and the common electrode; The common layer functions as either an electron injection layer or a hole injection layer in the first and second light-emitting elements.

5. In any one of claims 1 to 4, the first pixel electrode and the second pixel electrode are provided on an insulating layer; the insulating layer has a first convex portion in a region overlapping the first pixel electrode, The insulating layer has a second convex portion in a region overlapping with the second pixel electrode.

6. A display device according to any one of claims 1 to 5, A display module having at least one of a connector and an integrated circuit.

7. A display module according to claim 6; An electronic device having at least one of a housing, a battery, a camera, a speaker, and a microphone.

8. Forming an insulating layer; forming a conductive film, a first light-emitting film, an intermediate film, a second light-emitting film, and a sacrificial film in this order on the insulating layer; etching the sacrificial film, the second light-emitting film, the intermediate film, the first light-emitting film, and the conductive film to form a first pixel electrode on the insulating layer, a second pixel electrode, a first light-emitting layer on the first pixel electrode, a second light-emitting layer on the second pixel electrode, a first intermediate layer on the first light-emitting layer, a second intermediate layer on the second light-emitting layer, a third light-emitting layer on the first intermediate layer, a fourth light-emitting layer on the second intermediate layer, a first sacrificial layer on the third light-emitting layer, and a second sacrificial layer on the fourth light-emitting layer; forming an insulating film covering at least a portion of side surfaces of the first and second pixel electrodes, side surfaces of the first to fourth light emitting layers, side surfaces of the first and second intermediate layers, and side surfaces and an upper surface of the first and second sacrificial layers; Etching the insulating film to form a first sidewall covering at least a part of a side surface of the first pixel electrode and a second sidewall covering at least a part of a side surface of the second pixel electrode; removing the first sacrificial layer and the second sacrificial layer; A method for manufacturing a display device, comprising forming a common electrode over the third light-emitting layer and the fourth light-emitting layer.

9. Forming an insulating layer; forming a conductive film, a first light-emitting film, an intermediate film, a second light-emitting film, and a sacrificial film in this order on the insulating layer; etching the sacrificial film, the second light-emitting film, the intermediate film, the first light-emitting film, and the conductive film to form a first pixel electrode on the insulating layer, a second pixel electrode, a first light-emitting layer on the first pixel electrode, a second light-emitting layer on the second pixel electrode, a first intermediate layer on the first light-emitting layer, a second intermediate layer on the second light-emitting layer, a third light-emitting layer on the first intermediate layer, a fourth light-emitting layer on the second intermediate layer, a first sacrificial layer on the third light-emitting layer, and a second sacrificial layer on the fourth light-emitting layer; forming a first insulating film covering at least a portion of side surfaces of the first and second pixel electrodes, side surfaces of the first to fourth light emitting layers, side surfaces of the first and second intermediate layers, and side surfaces and an upper surface of the first and second sacrificial layers; forming a second insulating film on the first insulating film; etching the first insulating film and the second insulating film to form a first sidewall covering at least a part of a side surface of the first pixel electrode, a second sidewall covering at least a part of a side surface of the second pixel electrode, a third sidewall covering at least a part of a side surface of the first sidewall, and a fourth sidewall covering at least a part of a side surface of the second sidewall; removing the first sacrificial layer and the second sacrificial layer; A method for manufacturing a display device, comprising forming a common electrode over the third light-emitting layer and the fourth light-emitting layer.

10. In claim 8 or 9, A method for manufacturing a display device, comprising the steps of: etching the conductive film by using the first sacrificial layer and the second sacrificial layer as a mask.

11. In any one of claims 8 to 10, forming a protective layer on the common electrode; forming a first colored layer having an area overlapping with the first and third light-emitting layers and a second colored layer having an area overlapping with the second and fourth light-emitting layers on the protective layer; A method for manufacturing a display device, wherein the first colored layer and the second colored layer have a function of transmitting light of different colors.

12. In any one of claims 8 to 11, after removing the first sacrificial layer and the second sacrificial layer, forming a common layer having a function as either an electron injection layer or a hole injection layer on the third light-emitting layer and on the fourth light-emitting layer; The method for manufacturing a display device further comprises forming the common electrode on the common layer.

13. In any one of claims 8 to 12, The method for manufacturing a display device further comprises forming a recess in the insulating layer in the step of etching the conductive film.