Display device and manufacturing method thereof

Abstract

Provided is a display device that has a high definition or a high resolution. The display device is fabricated by a method comprising: forming a conductive film, a first layer, and a first sacrificial layer; processing the first layer and the first sacrificial layer to expose a part of the conductive film; forming a second layer and a second sacrificial on the first sacrificial layer and the conductive film; processing the second layer and the second sacrificial layer to expose a part of the conductive film; processing the conductive film to form a first pixel electrode overlapping the first sacrificial layer and a second pixel electrode overlapping the second sacrificial layer; forming a two-layer insulating film covering at least the side surfaces of the first pixel electrode, second pixel electrode, first layer, and second layer, the side surface and upper surface of the first sacrificial layer, and the side surface and the upper surface of the second sacrificial layer; processing the two-layer insulating film to form a side wall covering the side surfaces of at least the first pixel layer and the first layer; and removing the first sacrificial layer and the second sacrificial layer to form a common electrode on the first layer and second layer.

Description

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

[0001] 1. Field of the Invention One embodiment of the present invention relates to a display device, a display module, and an electronic device. 2. Description of the Related Art One embodiment of the present invention relates to a manufacturing method of a display device.

[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 device (also referred to as a light-emitting element) has been developed. A light-emitting device (also referred to as an EL device or an EL element) utilizing an 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 device (also called an organic EL element).

[0007] International Publication No. 2018 / 087625

[0008] When manufacturing a display device having a plurality of organic EL devices each emitting a different light color, it is necessary to form the light-emitting layers each emitting a different light color in an island shape.

[0009] For example, island-shaped light-emitting layers can be formed by vacuum deposition using a metal mask (also known as a shadow mask). However, this method can result in deviations in the shape and position of the island-shaped light-emitting layers from the design due to various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and the spread of the contours of the formed film due to vapor scattering, making it difficult to achieve high-definition and high-aperture displays. Furthermore, during deposition, the contours of the layer can become blurred, resulting in thin edges. In other words, the thickness of the island-shaped light-emitting layer can vary depending on the location. Furthermore, when fabricating large, high-resolution, or high-definition display devices, there is a concern that low manufacturing yields may be caused by low dimensional accuracy of the metal mask and deformation due to heat, etc.

[0010] Furthermore, when manufacturing display devices using a vacuum deposition method with a metal mask, the metal mask must be cleaned periodically, which stops the process. Therefore, it is desirable to prepare at least two lines of manufacturing equipment, and use one manufacturing equipment while the other is under maintenance. Considering mass production, multiple manufacturing equipment lines are required. Therefore, there is a problem in 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 small-sized display device.An object of one embodiment of the present invention is to provide a highly reliable 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 small-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.

[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 includes forming an insulating layer, forming a conductive film over the insulating layer, forming a first layer over the conductive film, forming a first sacrificial layer over the first layer, processing the first layer and the first sacrificial layer to expose a part of the conductive film, forming a second layer over the first sacrificial layer and the conductive film, forming a second sacrificial layer over the second layer, processing the second layer and the second sacrificial layer to expose a part of the conductive film, and processing the conductive film to form a first pixel electrode overlapping with the first sacrificial layer and a second pixel electrode overlapping with the second sacrificial layer, and forming a first pixel electrode overlapping with the second sacrificial layer. a first insulating film covering the side surfaces of the first pixel electrode, the side surfaces of the first layer, the side surfaces of the second layer, the side surfaces and top surface of the first sacrificial layer, and the side surfaces and top surface of the second sacrificial layer; a second insulating film on the first insulating film; and processing the first insulating film and the second insulating film to form first side walls and second side walls on the first side walls that cover at least the side surfaces of the first pixel electrode and the side surfaces of the first layer; removing the first sacrificial layer and the second sacrificial layer; and forming a common electrode on the first layer and the second layer.

[0015] It is preferable to form a first sacrificial film and a second sacrificial film on the first sacrificial film as the first sacrificial layer, form a first resist mask on the second sacrificial film, process the second sacrificial film using the first resist mask, remove the first resist mask, use the processed second sacrificial film as a hard mask to process the first sacrificial film, and then use the processed first sacrificial film as a hard mask to process the first layer.

[0016] It is preferable to process the conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask.

[0017] The first layer may have a first light-emitting unit, a charge generating layer on the first light-emitting unit, and a second light-emitting unit on the charge generating layer, and the first and second light-emitting units may have light-emitting layers that emit light of the same color.

[0018] After removing the first sacrificial layer and the second sacrificial layer, a third layer may be formed on the first layer and the second layer, and a common electrode may be formed on the third layer.

[0019] In the process of processing the conductive film, a recess may be formed in the insulating layer.

[0020] One embodiment of the present invention is a display device including a first light-emitting device, a second light-emitting device, a first sidewall, and a second sidewall. The first light-emitting device includes a first pixel electrode, a first light-emitting layer over the first pixel electrode, and a common electrode over the first light-emitting layer. The second light-emitting device includes a second pixel electrode, a second light-emitting layer over the second pixel electrode, and a common electrode over the second light-emitting layer. The first light-emitting device and the second light-emitting device have a function of emitting light of different colors. The first sidewall covers at least a side surface of the first pixel electrode and a side surface of the first light-emitting layer. The second sidewall overlaps with at least a side surface of the first pixel electrode and a side surface of the first light-emitting layer via the first sidewall.

[0021] The first light-emitting device may have a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, and a first electron transport layer on the first light-emitting layer, each of which has a side surface covered by the first sidewall, and may further have an electron injection layer on the first electron transport layer. Alternatively, the first light-emitting device may have a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, a first electron transport layer on the first light-emitting layer, and a first electron injection layer on the first electron transport layer, each of which has a side surface covered by the first sidewall.

[0022] One aspect of the present invention is a light-emitting device having a first light-emitting device, a second light-emitting device, a first sidewall, and a second sidewall. The first light-emitting device has a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, a second light-emitting unit on the first charge generation layer, and a common electrode on the second light-emitting unit. The second light-emitting device has a second pixel electrode, a third light-emitting unit on the second pixel electrode, and a common electrode on the third light-emitting unit. a second charge generation layer on the first pixel electrode, a fourth light-emitting unit on the second charge generation layer, and a common electrode on the fourth light-emitting unit, wherein the first light-emitting device and the second light-emitting device have the function of emitting light of different colors from each other, the first sidewall covers at least a side surface of the first pixel electrode and a side surface of the first charge generation layer, and the second sidewall overlaps at least a side surface of the first pixel electrode and a side surface of the first charge generation layer via the first sidewall.

[0023] Preferably, the first and second light-emitting units each emit light of a first color, and the third and fourth light-emitting units each emit light of a second color.

[0024] One aspect of the present invention provides a light-emitting device having a first light-emitting device, a second light-emitting device, a third light-emitting device, a first sidewall, and a second sidewall. The first light-emitting device has a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, a second light-emitting unit on the first charge generation layer, and a common electrode on the second light-emitting unit. The second light-emitting device has a second pixel electrode, a third light-emitting unit on the second pixel electrode, a second charge generation layer on the third light-emitting unit, a fourth light-emitting unit on the second charge generation layer, and a common electrode on the fourth light-emitting unit. the third light-emitting device has a third pixel electrode, a fifth light-emitting unit on the third pixel electrode, a third charge generation layer on the fifth light-emitting unit, a sixth light-emitting unit on the third charge generation layer, and a common electrode on the sixth light-emitting unit; the first light-emitting device, the second light-emitting device, and the third light-emitting device each have the function of emitting light of a different color; the first sidewall covers at least a side surface of the first pixel electrode and a side surface of the first charge generation layer; and the second sidewall overlaps at least a side surface of the first pixel electrode and a side surface of the first charge generation layer via the first sidewall.

[0025] Preferably, the first and second light-emitting units emit light of a first color, the third and fourth light-emitting units emit light of a second color, and the fifth and sixth light-emitting units emit light of a third color, where the first color is red, the second color is green, and the third color is blue.

[0026] It is preferable to have a protective layer on the common electrode.

[0027] The first light emitting device and the second light emitting device may be disposed on an insulating layer having a recess.

[0028] There may be an air gap between the first light emitting device and the second light emitting device.

[0029] One embodiment of the present invention is a display module including a display device having any of the above structures, and including a connector such as a flexible printed circuit (FPC) or a tape carrier package (TCP) attached thereto, or a display module including an integrated circuit (IC) mounted thereon by a chip-on-glass (COG) method, a chip-on-film (COF) method, or the like.

[0030] One embodiment of the present invention is an electronic device including the above-described display module and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0031] 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 small-sized display device can be provided. According to one embodiment of the present invention, a highly reliable display device can be provided.

[0032] 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 small-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 a high yield can be provided.

[0033] 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.

[0034] FIG. 1A is a top view showing an example of a display device. FIG. 1B is a cross-sectional view showing an example of a display device. FIG. 2A is a top view showing an example of a display device. FIG. 2B is a cross-sectional view showing an example of a display device. FIGS. 3A to 3F are top views showing an example of a pixel. FIGS. 4A to 4F are top views showing an example of a pixel. FIGS. 5A to 5G are top views showing an example of a pixel. FIGS. 6A to 6D are top views showing an example of a pixel. FIGS. 7A to 7D are top views showing an example of a pixel. FIGS. 7E to 7G are cross-sectional views showing an example of a display device. FIGS. 8A to 8C are top views showing an example of a manufacturing method of a display device. FIGS. 9A to 9C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 10A to 10C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 11A to 11C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 12A to 12C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 13A to 13C are cross-sectional views illustrating an example of a method for manufacturing a display device. FIGS. 14A to 14E are cross-sectional views illustrating an example of a method for manufacturing a display device. FIGS. 15A to 15C are cross-sectional views illustrating an example of a display device. FIGS. 16A and 16B are cross-sectional views illustrating an example of a display device. FIGS. 17A and 17B are cross-sectional views illustrating an example of a display device. FIGS. 18A and 18B are cross-sectional views illustrating an example of a display device. FIG. 19 is a perspective view illustrating an example of a display device. FIG. 20A is a cross-sectional view illustrating an example of a display device. FIGS. 20B and 20C are cross-sectional views illustrating an example of a transistor. FIG. 21 is a cross-sectional view illustrating an example of a display device. FIGS. 22A and 22B are perspective views illustrating an example of a display module. FIG. 23 is a cross-sectional view illustrating an example of a display device. FIG. 24 is a cross-sectional view illustrating an example of a display device. FIG. 25 is a cross-sectional view illustrating an example of a display device. FIG. 26A is a block diagram illustrating an example of a display device. FIGS. 26B to 26D are diagrams illustrating an example of a pixel circuit. FIGS. 27A to 27D are diagrams illustrating an example of a transistor. 28A and 28B are diagrams illustrating an example of an electronic device, 29A and 29B are diagrams illustrating an example of an electronic device, and 30A and 30B are diagrams illustrating an example of an electronic device.31A to 31D are diagrams showing an example of an electronic device, and FIGS. 32A to 32G are diagrams showing an example of an electronic device.

[0035] 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.

[0036] 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. Furthermore, when referring to similar functions, the same hatching pattern may be used and no particular reference numeral may be assigned.

[0037] 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.

[0038] 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."

[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 FIGS.

[0040] In a manufacturing method of a display device according to one embodiment of the present invention, a conductive film is formed, and a first layer (which can be referred to as an EL layer or a part of an EL layer) including a light-emitting layer emitting light of a first color is formed over the entire surface. Then, a first sacrificial layer is formed over the first layer. Then, a first resist mask is formed over the first sacrificial layer, and the first layer and the first sacrificial layer are processed using the first resist mask to form an island-shaped first layer. Subsequently, a second layer (which can be referred to as an EL layer or a part of an EL layer) including a light-emitting layer emitting light of a second color is formed in an island shape using a second sacrificial layer and a second resist mask, similar to the first layer.

[0041] As described above, in the manufacturing method of a display device according to one embodiment of the present invention, the island-shaped EL layer is formed by forming the EL layer over the entire surface and then processing it, rather than by using a metal mask having a fine pattern. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be formed separately for each color, it is possible to realize a display device that is extremely vivid, has high contrast, and has high display quality. Furthermore, by providing a sacrificial layer (which may also be referred to as a mask layer) on the EL layer, damage to the EL layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0042] While it is difficult to achieve a spacing of less than 10 μm between adjacent light-emitting devices using, for example, a metal mask, the above-described method can narrow the spacing to less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less. Furthermore, by using, for example, an exposure device for LSIs, the spacing can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, or even 50 nm or less. This significantly reduces the area of ​​the non-light-emitting region that may exist between two light-emitting devices, enabling the aperture ratio to approach 100%. For example, the aperture ratio can be 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more, and even less than 100%.

[0043] Furthermore, the pattern of the EL layer itself (also known as the processing size) can be made much smaller than when a metal mask is used. Furthermore, for example, when a metal mask is used to separately fabricate an EL layer, thickness variations occur between the center and edges of the EL layer, resulting in a smaller effective area that can be used as a light-emitting region relative to the area of ​​the EL layer. On the other hand, the above-described fabrication method processes a film formed to a uniform thickness, allowing island-shaped EL layers to be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as a light-emitting region. This allows the fabrication of a display device that combines high definition and a high aperture ratio.

[0044] After forming the EL layers emitting light of each color, the sacrificial layer remaining on each EL layer can be used as a hard mask to process the conductive film to form pixel electrodes. Since there is no need to provide a separate mask for forming the pixel electrodes in an island shape, the manufacturing cost of the display device can be reduced. Furthermore, there is no need to provide an insulating layer between the pixel electrodes and the EL layer to cover the edges of the pixel electrodes, so the distance between adjacent light-emitting devices can be made extremely narrow. This allows for higher definition or higher resolution of the display device. Furthermore, there is no need for a mask for forming the insulating layer, so the manufacturing cost of the display device can be reduced.

[0045] Here, the first layer and the second layer each include at least a light-emitting layer and preferably consist of 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 device. Therefore, it is preferable that the first layer and the second layer each include a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer.

[0046] In light-emitting devices emitting light of different colors, it is not necessary to separately fabricate all layers constituting the EL layer; some layers can be formed in the same process. In a method for fabricating a display device according to one embodiment of the present invention, some layers constituting the EL layer are formed in an island shape for each color, and then the sacrificial layer is removed. The remaining layers constituting the EL layer and a common electrode (also referred to as an upper electrode) are formed (as a single film) in common to the light-emitting devices of each color. For example, a carrier injection layer and a common electrode can be formed in common to the light-emitting devices of each color. Meanwhile, the carrier injection layer is often a relatively highly conductive layer among the EL layers. Therefore, contact between the carrier injection layer and the side surface of a part of the island-shaped EL layer or the side surface of the pixel electrode may cause a short circuit in the light-emitting device. Even when the carrier injection layer is formed in an island shape and a common electrode is formed in common to the light-emitting devices of each color, contact between the common electrode and the side surface of the EL layer or the side surface of the pixel electrode may cause a short circuit in the light-emitting device.

[0047] Therefore, a display device according to one embodiment of the present invention has a sidewall (also referred to as a sidewall, a sidewall protective layer, a sidewall insulating film, an insulating layer, or the like) covering the side surfaces of the island-shaped light-emitting layer and the side surfaces of the pixel electrode.

[0048] This prevents at least a portion of the island-shaped EL layer and the pixel electrode from coming into contact with the carrier injection layer or the common electrode, thereby preventing short circuits in the light-emitting device and improving the reliability of the light-emitting device.

[0049] A display device of one embodiment of the present invention includes a pixel electrode functioning as an anode; a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer, each of which has an island shape and is provided in this order over the pixel electrode; sidewalls provided so as to cover side surfaces of the pixel electrode, the hole injection layer, the hole transport layer, the light-emitting layer, and the electron transport layer; an electron injection layer provided over the electron transport layer; and a common electrode provided over the electron injection layer and functioning as a cathode.

[0050] Alternatively, a display device of one embodiment of the present invention includes a pixel electrode that functions as a cathode; an electron-injection layer, an electron-transport layer, a light-emitting layer, and a hole-transport layer that are provided in this order over the pixel electrode, each of which has an island shape; sidewalls that are provided so as to cover side surfaces of the pixel electrode, the electron-injection layer, the electron-transport layer, the light-emitting layer, and the hole-transport layer; a hole-injection layer that is provided over the hole-transport layer; and a common electrode that is provided over the hole-injection layer and functions as an anode.

[0051] Alternatively, a display device according to one embodiment of the present invention includes a pixel electrode, a first light-emitting unit over the pixel electrode, a charge generation layer (also referred to as an intermediate layer) over the first light-emitting unit, a second light-emitting unit over the charge generation layer, sidewalls provided so as to cover side surfaces of the pixel electrode, the first light-emitting unit, the charge generation layer, and the second light-emitting unit, and a common electrode provided over the second light-emitting unit. Note that one or both of an electron-transport layer and an electron-injection layer may be provided as a layer common to light-emitting devices of each color between the second light-emitting unit and the common electrode.

[0052] Among EL layers, the hole injection layer, the electron injection layer, the charge generation layer, and the like are often layers with relatively high conductivity. In the display device of one embodiment of the present invention, the side surfaces of these layers are covered with an insulating layer, so that contact with a common electrode or the like can be suppressed. Therefore, short circuits in the light-emitting device can be suppressed, and the reliability of the light-emitting device can be improved.

[0053] By adopting such a configuration, a display device with high definition or resolution and high reliability can be manufactured. For example, there is no need to artificially increase the definition by applying a special pixel arrangement method such as a pen tile method, and even an arrangement method using three or more sub-pixels per pixel can realize an extremely high-definition display device. For example, a display device with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, and a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, even 3000 ppi or more, or even 5000 ppi or more can be realized.

[0054] The sidewalls may have a single-layer structure or a laminated structure. In particular, it is preferable to use sidewalls with a two-layer structure. For example, since the first layer of the sidewalls is formed in contact with the EL layer, it is preferable to form it using atomic layer deposition (ALD), which causes less film damage. Furthermore, it is preferable to form the second layer of the sidewalls using sputtering, chemical vapor deposition (CVD), or plasma enhanced chemical vapor deposition (PECVD), which have a faster film formation rate than the ALD method. This allows for the production of highly reliable display devices with high productivity.

[0055] For example, an aluminum oxide film formed by ALD can be used as the first layer of the sidewall, and a silicon nitride film or silicon nitride oxide film formed by sputtering or PECVD can be used as the second layer of the sidewall.

[0056] [Structure Example 1 of Display Device] FIGS. 1A and 1B illustrate a display device of one embodiment of the present invention.

[0057] 1A shows a top view of a display device 100. The display device 100 has a display section in which a plurality of pixels 110 are arranged in a matrix, and a connection section 140 outside the display section. The connection section 140 can also be called a cathode contact section.

[0058] A stripe arrangement is applied to the pixel 110 shown in Fig. 1A. The pixel 110 shown in Fig. 1A is composed of three subpixels, 110a, 110b, and 110c. The subpixels 110a, 110b, and 110c each have a light-emitting device that emits light of a different color. Examples of the subpixels 110a, 110b, and 110c include three subpixels of red (R), green (G), and blue (B), and three subpixels of yellow (Y), cyan (C), and magenta (M).

[0059] The top surface shape of the sub-pixel shown in FIG. 1A corresponds to the top surface shape of the light-emitting region.

[0060] Furthermore, the circuit layout constituting the subpixels is not limited to the range of the subpixels shown in Fig. 1A and may be located outside of it. For example, some or all of the transistors included in the subpixel 110a may be located outside the range of the subpixel 110a shown in Fig. 1A. For example, the transistor included in the subpixel 110a may have a portion located within the range of the subpixel 110b and a portion located within the range of the subpixel 110c.

[0061] 1A shows the subpixels 110a, 110b, and 110c as having the same or approximately the same aperture ratio (which can also be referred to as the size or size of the light-emitting region), but this is not a limitation of one embodiment of the present invention. The aperture ratios of the subpixels 110a, 110b, and 110c can be determined as appropriate. The aperture ratios of the subpixels 110a, 110b, and 110c may be different from one another, or two or more of the subpixels 110a, 110b, and 110c may be the same or approximately the same.

[0062] 1A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction. Note that subpixels of different colors may also be arranged side by side in the Y direction, and subpixels of the same color may also be arranged side by side in the X direction.

[0063] 1A 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.

[0064] FIG. 1B shows a cross-sectional view taken along the dashed line X1-X2 in FIG. 1A.

[0065] 1B , display device 100 includes light-emitting devices 130a, 130b, and 130c on transistor-containing layer 101, and protective layers 131 and 132 that cover these light-emitting devices. Substrate 120 is bonded to protective layer 132 with resin layer 122. In addition, a sidewall 125a and a sidewall 125b on sidewall 125a are provided in the region between adjacent light-emitting devices.

[0066] 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 device is formed, a bottom emission type that emits light toward a substrate on which a light-emitting device is formed, and a dual emission type that emits light from both sides.

[0067] The transistor-containing layer 101 may have a stacked structure in which, for example, a plurality of transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The transistor-containing layer 101 may have a recess between adjacent light-emitting devices. For example, a recess may be provided in an insulating layer located on the outermost surface of the transistor-containing layer 101. Configuration examples of the transistor-containing layer 101 will be described later in Embodiments 3 and 4.

[0068] The light emitting devices 130a, 130b, and 130c each emit light of a different color, and preferably emit light of three colors, for example, red (R), green (G), and blue (B).

[0069] As the light-emitting devices 130a, 130b, and 130c, for example, it is preferable to use an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode). Examples of the light-emitting substance (also referred to as a light-emitting material) included in the light-emitting device include a fluorescent substance (fluorescent material), a phosphorescent substance (phosphorescent material), and a substance exhibiting thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) material). Note that, as the TADF material, a material in thermal equilibrium between a singlet excited state and a triplet excited state may be used. Such a TADF material has a short emission lifetime (excitation lifetime), and therefore, can suppress a decrease in efficiency in the high-brightness region of the light-emitting device. Furthermore, an inorganic compound (such as a quantum dot material) may be used as the light-emitting substance contained in the light-emitting device.

[0070] A light-emitting device has an EL layer between a pair of electrodes, one of which may be referred to as a pixel electrode and the other as a common electrode in this specification and the like.

[0071] A light-emitting device has a pair of electrodes, one of which functions as an anode and the other as a cathode. In the following, an example will be described in which the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0072] The light-emitting device 130a has a pixel electrode 111a on a layer 101 including a transistor, an island-shaped first layer 113a on the pixel electrode 111a, a fifth layer 114 on the island-shaped first layer 113a, and a common electrode 115 on the fifth layer 114.

[0073] In this embodiment, a case where the light-emitting device has a tandem structure will be described as an example. Therefore, the light-emitting device of this embodiment has a configuration in which a plurality of light-emitting units each having a light-emitting layer are provided, and a charge generation layer is provided between the two light-emitting units. The configuration of the light-emitting device is not particularly limited, and it may have a single structure. Note that an example of the configuration of the light-emitting device will be described later in embodiment 2.

[0074] The first layer 113a includes a first light-emitting unit 181a on the pixel electrode 111a, a charge generation layer 182a on the first light-emitting unit 181a, and a second light-emitting unit 183a on the charge generation layer 182a. In the light-emitting device 130a, the first layer 113a and the fifth layer 114 can be collectively referred to as an EL layer. The first light-emitting unit 181a and the second light-emitting unit 183a may be configured to emit light of the same color or different colors.

[0075] The light-emitting device 130b includes a pixel electrode 111b on the transistor-containing layer 101, an island-shaped second layer 113b on the pixel electrode 111b, a fifth layer 114 on the island-shaped second layer 113b, and a common electrode 115 on the fifth layer 114. The second layer 113b includes a first light-emitting unit 181b on the pixel electrode 111b, a charge generation layer 182b on the first light-emitting unit 181b, and a second light-emitting unit 183b on the charge generation layer 182b. In the light-emitting device 130b, the second layer 113b and the fifth layer 114 can be collectively referred to as an EL layer. The first light-emitting unit 181b and the second light-emitting unit 183b may be configured to emit light of the same color or different colors.

[0076] The light-emitting device 130c includes a pixel electrode 111c on the transistor-containing layer 101, an island-shaped third layer 113c on the pixel electrode 111c, a fifth layer 114 on the island-shaped third layer 113c, and a common electrode 115 on the fifth layer 114. The third layer 113c includes a first light-emitting unit 181c on the pixel electrode 111c, a charge generation layer 182c on the first light-emitting unit 181c, and a second light-emitting unit 183c on the charge generation layer 182c. In the light-emitting device 130c, the third layer 113c and the fifth layer 114 can be collectively referred to as an EL layer. The first light-emitting unit 181c and the second light-emitting unit 183c may be configured to emit light of the same color or different colors.

[0077] The light emitting devices of each color share the same film as a common electrode. The common electrode shared by the light emitting devices of each color is electrically connected to a conductive layer provided in the connection section 140.

[0078] Of the pixel electrode and the common electrode, the electrode from which light is extracted is preferably made of a conductive film that transmits visible light, and the electrode from which light is not extracted is preferably made of a conductive film that reflects visible light.

[0079] The pair of electrodes (pixel electrode and common electrode) of the light-emitting device can be formed from a material such as a metal, an alloy, an electrically conductive compound, or a mixture thereof. 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 aluminum-containing alloy (aluminum alloy) such as an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and an alloy of silver and magnesium, 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), magnesium (Mg), 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.

[0080] The light-emitting device preferably has a micro-optical resonator (microcavity) structure. Therefore, one of a pair of electrodes of the light-emitting device preferably has a transmissive and reflective electrode for visible light, and the other preferably has a reflective electrode for visible light. By having the light-emitting device have a microcavity structure, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby intensifying the light emitted from the light-emitting device.

[0081] 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).

[0082] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for a light-emitting device. 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.

[0083] The first layer 113 a, the second layer 113 b, and the third layer 113 c are each provided in an island shape. Each of the first layer 113 a, the second layer 113 b, and the third layer 113 c has a light-emitting layer. It is preferable that the first layer 113 a, the second layer 113 b, and the third layer 113 c each have a light-emitting layer that emits light of a different color.

[0084] 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 a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0085] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] The light-emitting layer preferably includes, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-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 for efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting device.

[0090] The first layer 113a, the second layer 113b, and the third layer 113c may further include, as a layer other than the light-emitting layer, a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties (also referred to as a hole-transport material), a hole-blocking material, a substance with high electron-transport properties (also referred to as an electron-transport material), a substance with high electron-injection properties, an electron-blocking material, a bipolar substance (a substance with high electron-transport properties and high hole-transport properties, also referred to as a bipolar material), or the like.

[0091] For example, the first layer 113a, the second layer 113b, and the third layer 113c may each include one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0092] The EL layer may include one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer, as layers commonly formed in the light-emitting devices of each color. For example, a carrier injection layer (hole injection layer or electron injection layer) may be formed as the fifth layer 114. It is also possible to form all layers of the EL layer separately for each color. In other words, the EL layer does not need to include a layer commonly formed in the light-emitting devices of each color.

[0093] Each of the second light-emitting units 183 a, 183 b, and 183 c preferably includes a light-emitting layer and a carrier transport layer on the light-emitting layer. This prevents the light-emitting layer from being exposed to the outermost surface during the manufacturing process of the display device 100, thereby reducing damage to the light-emitting layer. This improves the reliability of the light-emitting device.

[0094] The side surfaces of the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c are covered with side walls 125a, 125b, and the side walls 125a, 125b are located between the side surfaces of these layers and the fifth layer 114 (or the common electrode 115). This prevents the fifth layer 114 (or the common electrode 115) from coming into contact with any of the side surfaces of the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing short circuits in the light-emitting device.

[0095] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a substance 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).

[0096] 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 transporting material. The hole transporting 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 substance 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.

[0097] 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 concentration of 1×10 −６ cm ２ / 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.

[0098] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a substance with high electron injection properties. Examples of the substance with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the substance with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0099] 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.

[0100] Alternatively, an electron transporting material may be used for the electron injection layer. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the electron transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring may be used.

[0101] 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.

[0102] 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 temperature (Tg) and is superior in heat resistance compared to BPhen.

[0103] In addition, when a light-emitting device with a tandem structure is fabricated, a charge generation layer is provided between two light-emitting units. The charge generation layer has at least a charge generation region. The charge generation layer has the function of injecting electrons into one of the two light-emitting units and injecting holes into the other when a voltage is applied between a pair of electrodes.

[0104] As described above, the charge generation layer has at least a charge generation region. The charge generation region preferably contains an acceptor material, for example, a hole transport material and an acceptor material applicable to the hole injection layer.

[0105] The charge generation layer preferably includes a layer containing a substance with high electron injection properties. This layer may also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing the electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be alleviated, so that electrons generated in the charge generation region can be easily injected into the electron transport layer.

[0106] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and may contain, for example, an alkali metal compound or an alkaline earth metal compound. Specifically, the electron injection buffer layer preferably contains an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and may contain an inorganic compound containing lithium and oxygen (lithium oxide (Li ２In addition, the electron injection buffer layer can be suitably made of the materials applicable to the electron injection layer described above.

[0107] The charge generation layer preferably has a layer containing a substance with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. When the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or the electron transport layer) and smoothly transferring electrons.

[0108] For the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper (II) phthalocyanine (abbreviated as CuPc) or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0109] It should be noted that the charge generation region, electron injection buffer layer, and electron relay layer may not be clearly distinguishable from one another depending on their cross-sectional shapes or characteristics.

[0110] The charge generation layer may contain a donor material instead of an acceptor material. For example, the charge generation layer may contain a layer containing an electron transport material and a donor material that can be used for the electron injection layer.

[0111] When light-emitting units are stacked, an increase in driving voltage can be suppressed by providing a charge generating layer between two light-emitting units.

[0112] The light-emitting device can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. The layers constituting the light-emitting device can be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet printing, or coating.

[0113] The sidewalls 125a and 125b can each 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.

[0114] 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.

[0115] The sidewall 125 a is preferably formed by ALD, which causes less damage to the first layer 113 a, the second layer 113 b, and the third layer 113 c, and therefore is preferably formed by ALD, for example, using an aluminum oxide film formed by ALD.

[0116] The sidewall 125b is preferably formed by a sputtering method, a CVD method, a PECVD method, or the like, which has a faster film formation rate than the ALD method. For example, the sidewall 125b can be formed using a silicon nitride film formed by a sputtering method or a silicon nitride oxide film formed by a PECVD method. This allows a highly reliable display device to be manufactured with high productivity.

[0117] It is preferable that the light-emitting devices 130 a, 130 b, and 130 c have protective layers 131 and 132. Providing the protective layers 131 and 132 can improve the reliability of the light-emitting devices. In this embodiment, a two-layer structure of the protective layers 131 and 132 will be described as an example, but the protective layers may have a single-layer structure or a stacked structure of three or more layers.

[0118] There is no limitation on the conductivity of the protective layers 131 and 132. The protective layers 131 and 132 can be formed using at least one of an insulating film, a semiconductor film, and a conductive film.

[0119] The protective layers 131 and 132 have inorganic films, which can prevent oxidation of the common electrode 115 and prevent impurities (moisture, oxygen, etc.) from entering the light-emitting devices 130a, 130b, and 130c, thereby suppressing deterioration of the light-emitting devices and improving the reliability of the display device.

[0120] The protective layers 131 and 132 can be made of 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.

[0121] 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.

[0122] 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 layers 131 and 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.

[0123] When light emitted from the light-emitting device is extracted through the protective layers 131 and 132, it is preferable that the protective layers 131 and 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.

[0124] 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 as the protective layers 131 and 132. By using such a stacked structure, impurities (water, oxygen, etc.) can be prevented from entering the EL layer side.

[0125] Furthermore, the protective layers 131 and 132 may include an organic film. For example, the protective layer 132 may include both an organic film and an inorganic film.

[0126] 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 atomic layer deposition (ALD), and the protective layer 132 may be formed by sputtering.

[0127] The upper end portions of the pixel electrodes 111a, 111b, and 111c are not covered with an insulating layer, which allows the distance between adjacent light-emitting devices to be extremely narrow, thereby enabling a high-definition or high-resolution display device.

[0128] 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. Also, 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.

[0129] In this specification and the like, a structure in which different light-emitting layers are fabricated or different light-emitting layers are painted for each color light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. The SBS structure allows the materials and configuration to be optimized for each light-emitting device, increasing the freedom of material and configuration selection and facilitating improvements in brightness and reliability.

[0130] In this specification and the like, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. Note that a white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0131] Light-emitting devices can be broadly divided into single structures and tandem structures. A single-structure device preferably has one light-emitting unit between a pair of electrodes, and the light-emitting unit includes one or more light-emitting layers. When two light-emitting layers are used to obtain white light emission, the light-emitting layers may be selected so that the emission colors of the two light-emitting layers are complementary to each other. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary to each other, a configuration in which the entire light-emitting device emits white light can be obtained. When three or more light-emitting layers are used to obtain white light emission, the emission colors of the three or more light-emitting layers may be combined to produce a configuration in which the entire light-emitting device emits white light.

[0132] A tandem-structure device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, light from the light-emitting layers of the light-emitting units may be combined to obtain white light emission. The configuration for obtaining white light emission is the same as that of the single-structure device. In a tandem-structure device, it is preferable to provide a charge-generating layer between the light-emitting units.

[0133] Furthermore, when comparing the above-described white light-emitting device (single structure or tandem structure) with a light-emitting device having an SBS structure, the light-emitting device having an SBS structure can reduce power consumption compared to the white light-emitting device. If it is desired to reduce power consumption, it is preferable to use a light-emitting device having an SBS structure. On the other hand, the manufacturing process of a white light-emitting device is simpler than that of a light-emitting device having an SBS structure, and therefore the manufacturing cost can be reduced or the manufacturing yield can be increased, making it preferable.

[0134] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices, the distance between EL layers, or the distance between pixel electrodes can be less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 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, the distance between the side surface of the first layer 113 a and the side surface of the second layer 113 b or the distance between the side surface of the second layer 113 b and the side surface of the third layer 113 c has a region of 1 μm or less, preferably a region of 0.5 μm (500 nm) or less, and more preferably a region of 100 nm or less.

[0135] A light-shielding layer may be provided on the surface of the substrate 120 facing the resin layer 122. Various optical members may 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. The outside of the substrate 120 may also be provided with an anti-static 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 the occurrence of scratches during use, an impact absorbing layer, etc.

[0136] 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 device is extracted. Using a flexible material for the substrate 120 can increase the flexibility of the display device and realize a flexible display. A polarizing plate may also be used as the substrate 120.

[0137] The substrate 120 can 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 can also be made of glass having a thickness sufficient to provide flexibility.

[0138] 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).

[0139] 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.

[0140] 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.

[0141] 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.

[0142] The resin layer 122 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. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Adhesive sheets or the like may also be used.

[0143] 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.

[0144] 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 display devices, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) in light-emitting devices.

[0145] 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.

[0146] As shown in FIG. 2A, a pixel can be configured to have four types of sub-pixels.

[0147] 2A shows a top view of the display device 100. The display device 100 has a display section in which a plurality of pixels 110 are arranged in a matrix, and a connection section 140 on the outside of the display section.

[0148] 2A is composed of four types of subpixels, 110a, 110b, 110c, and 110d. The subpixels 110a, 110b, 110c, and 110d each have a light-emitting device that emits light of a different color. Examples of the subpixels 110a, 110b, 110c, and 110d include subpixels of four colors (R, G, B, and white (W)) and subpixels of four colors (R, G, B, and Y).

[0149] FIG. 2A shows an example in which one pixel 110 is configured with two rows and three columns. The pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and three subpixels 110d in the bottom row (second row). In other words, the pixel 110 has the subpixels 110a and 110d in the left column (first column), the subpixels 110b and 110d in the center column (second column), and the subpixels 110c and 110d in the right column (third column). By aligning the subpixels in the top row and bottom row as shown in FIG. 2A, it is possible to efficiently remove dust and other contaminants that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0150] Fig. 2B shows a cross-sectional view taken along dashed line X3-X4 in Fig. 2A. The configuration shown in Fig. 2B is the same as that shown in Fig. 1B except that it includes a light-emitting device 130d. Therefore, a description of the same parts as those in Fig. 1B will be omitted.

[0151] 2B , display device 100 includes light-emitting devices 130a, 130b, 130c, and 130d on transistor-containing layer 101, and protective layers 131 and 132 that cover these light-emitting devices. Substrate 120 is bonded to protective layer 132 with resin layer 122. In addition, a sidewall 125a and a sidewall 125b on sidewall 125a are provided in the region between adjacent light-emitting devices.

[0152] The light emitting devices 130a, 130b, 130c, and 130d each emit light of a different color, and preferably, the light emitting devices 130a, 130b, 130c, and 130d emit light of four colors, for example, red (R), green (G), blue (B), and white (W).

[0153] The light-emitting device 130d has a pixel electrode 111d on the layer 101 including the transistor, an island-shaped fourth layer 113d on the pixel electrode 111d, a fifth layer 114 on the island-shaped fourth layer 113d, and a common electrode 115 on the fifth layer 114.

[0154] The fourth layer 113d includes a first light-emitting unit 181d on the pixel electrode 111d, a charge generation layer 182d on the first light-emitting unit 181d, and a second light-emitting unit 183d on the charge generation layer 182d. In the light-emitting device 130d, the fourth layer 113d and the fifth layer 114 can be collectively referred to as an EL layer.

[0155] The three sub-pixels 110d may each have an independent light-emitting device 130d, or may share one light-emitting device 130d. That is, the pixel 110 may have one or three light-emitting devices 130d.

[0156] [Pixel Layout] Next, pixel layouts different from those shown in Figures 1A and 2A will be described. There are no particular limitations on the arrangement of sub-pixels, and various methods can be applied. Examples of the arrangement of sub-pixels include a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0157] Examples of the top surface shape of the subpixel 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 subpixel corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0158] An S-stripe arrangement is applied to the pixel 110 shown in Fig. 3A. The pixel 110 shown in Fig. 3A is composed of three subpixels, namely, subpixels 110a, 110b, and 110c. For example, as shown in Fig. 4A, the subpixel 110a may be a blue subpixel B, the subpixel 110b may be a red subpixel R, and the subpixel 110c may be a green subpixel G.

[0159] The pixel 110 shown in FIG. 3B 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 subpixel having a more reliable light-emitting device can be made smaller in size. For example, as shown in FIG. 4B, the subpixel 110a may be a green subpixel G, the subpixel 110b may be a red subpixel R, and the subpixel 110c may be a blue subpixel B.

[0160] The pixels 124a and 124b shown in Fig. 3C are arranged in a Pentile arrangement. Fig. 3C shows an example in which a pixel 124a having subpixels 110a and 110b and a pixel 124b having subpixels 110b and 110c are arranged alternately. For example, as shown in Fig. 4C, the subpixel 110a may be a red subpixel R, the subpixel 110b may be a green subpixel G, and the subpixel 110c may be a blue subpixel B.

[0161] The pixels 124a and 124b shown in Figures 3D and 3E are arranged in a delta configuration. The pixel 124a has two subpixels (subpixels 110a and 110b) in the top row (first row) and one subpixel (subpixel 110c) in the bottom row (second row). The pixel 124b has one subpixel (subpixel 110c) in the top row (first row) and two subpixels (subpixels 110a and 110b) in the bottom row (second row). For example, as shown in Figure 4D, the subpixel 110a may be a red subpixel R, the subpixel 110b may be a green subpixel G, and the subpixel 110c may be a blue subpixel B.

[0162] FIG. 3D shows an example in which each subpixel has a substantially rectangular top surface shape with rounded corners, and FIG. 3E shows an example in which each subpixel has a circular top surface shape.

[0163] 3F shows an example in which subpixels of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper edges of two subpixels arranged in the column direction (e.g., subpixels 110a and 110b, or subpixels 110b and 110c) are misaligned. For example, as shown in FIG. 4E, the subpixel 110a may be a red subpixel R, the subpixel 110b may be a green subpixel G, and the subpixel 110c may be a blue subpixel B.

[0164] In photolithography, the finer the pattern to be processed, 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 process 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.

[0165] Furthermore, in a manufacturing method of a display device according to one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the material for the EL layer 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 that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer 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 EL layer.

[0166] In order to form the top surface of the EL layer into a desired shape, a technique for correcting a mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern coincide with each other. Specifically, the OPC technique adds a correction pattern to the corners of figures on the mask pattern.

[0167] In addition, even in the pixel 110 to which the stripe arrangement shown in FIG. 1A is applied, for example, as shown in FIG. 4F, the subpixel 110a can be a red subpixel R, the subpixel 110b can be a green subpixel G, and the subpixel 110c can be a blue subpixel B.

[0168] The pixel 110 shown in FIGS. 5A to 5C is configured in a stripe arrangement.

[0169] FIG. 5A shows an example in which each subpixel has a rectangular top surface shape, FIG. 5B shows an example in which each subpixel has a top surface shape that is a combination of two semicircles and a rectangle, and FIG. 5C shows an example in which each subpixel has an elliptical top surface shape.

[0170] The pixels 110 shown in FIGS. 5D to 5F are arranged in a matrix.

[0171] Figure 5D is an example in which each subpixel has a square top surface shape, Figure 5E is an example in which each subpixel has an approximately square top surface shape with rounded corners, and Figure 5F is an example in which each subpixel has a circular top surface shape.

[0172] The pixel 110 shown in Figures 5A to 5F is composed of four subpixels, 110a, 110b, 110c, and 110d. Each of the subpixels 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. For example, the subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively. For example, as shown in Figures 6A and 6B, the subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively. Alternatively, the subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and infrared-emitting subpixels, respectively.

[0173] 5G shows an example in which one pixel 110 is configured with two rows and three columns. 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 subpixel 110d across these three columns.

[0174] In the pixel 110 shown in Figures 2A and 5G, for example, as shown in Figures 6C and 6D, the subpixel 110a can be a red subpixel R, the subpixel 110b can be a green subpixel G, the subpixel 110c can be a blue subpixel B, and the subpixel 110d can be a white subpixel W.

[0175] The display device according to one embodiment of the present invention may include a light-receiving device in a pixel.

[0176] Of the four types of sub-pixels included in pixel 110 shown in FIG. 2A, three may be configured to include a light-emitting device, and the remaining one may be configured to include a light-receiving device.

[0177] The light receiving device may be, for example, a pn-type or pin-type photodiode. The light receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on the light receiving device and generates electric charges. The amount of electric charges generated by the light receiving device is determined based on the amount of light incident on the light receiving device.

[0178] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thin, lightweight, and large in area, and have a high degree of freedom in shape and design, making them applicable to a variety of display devices.

[0179] In one embodiment of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, the organic photodiode can be built into a display device using the organic EL device.

[0180] The light-receiving device has an active layer that functions as at least a photoelectric conversion layer 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.

[0181] For example, the subpixels 110a, 110b, and 110c may be subpixels of three colors, R, G, and B, and the subpixel 110d may be a subpixel having a light-receiving device. In this case, the fourth layer 113d may have at least an active layer.

[0182] Of the pair of electrodes that a light-receiving device has, one electrode functions as an anode and the other electrode functions as a cathode. The following describes an example in which the pixel electrode functions as the anode and the common electrode functions as the cathode. The light-receiving device can detect light incident on the light-receiving device, generate electric charges, and extract them as a current by applying a reverse bias between the pixel electrode and the common electrode. Alternatively, the pixel electrode may function as a cathode and the common electrode may function as an anode.

[0183] The same manufacturing method as for the light-emitting device can be applied to the light-receiving device. The island-shaped active layer (also called a photoelectric conversion layer) of the light-receiving device is formed by depositing a film to become the active layer on the entire surface and then processing it, rather than using a fine metal mask. Therefore, the island-shaped active layer can be formed with a uniform thickness. Furthermore, by providing a sacrificial layer on the active layer, damage to the active layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-receiving device.

[0184] Here, a layer shared by a light-receiving device and a light-emitting device may have different functions in the light-emitting device and in the light-receiving device. In this specification, components may be referred to based on their functions in the light-emitting device. For example, a hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Furthermore, a layer shared by a light-receiving device and a light-emitting device may have the same function in the light-emitting device and in the light-receiving device. A hole transport layer functions as a hole transport layer in both the light-emitting device and the light-receiving device, and an electron transport layer functions as an electron transport layer in both the light-emitting device and the light-receiving device.

[0185] The active layer of the light-receiving device includes a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In this embodiment, an example in which an organic semiconductor is used as the semiconductor of the active layer is shown. Using an organic semiconductor is preferable because the light-emitting layer and the active layer can be formed by the same method (e.g., vacuum deposition), allowing the use of a common manufacturing device.

[0186] The n-type semiconductor material of the active layer is fullerene (e.g., C ６０ Fullerene, C ７０Examples of electron-accepting organic semiconductor materials include fullerenes and fullerene derivatives. Fullerenes have a soccer ball-like shape, and this shape is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Because fullerenes have a deep LUMO level, they have extremely high electron-accepting (acceptor) properties. Normally, when π-electron conjugation (resonance) spreads on a plane, as in benzene, electron-donating (donor) properties increase, but fullerenes have a spherical shape, so they have high electron-accepting properties despite the large spread of π-electrons. High electron-accepting properties cause charge separation quickly and efficiently, making them useful as light-receiving devices. C ６０ Fullerene, C ７０ Both fullerenes and fluorenes have a wide absorption band in the visible light region, especially C ７０ Fullerene is C ６０ It is preferable because it has a larger π-electron conjugated system than fullerene and has a wide absorption band in the long wavelength region. Other fullerene derivatives include [6,6]-Phenyl-C71-butylic acid methyl ester (abbreviation: PC70BM), [6,6]-Phenyl-C61-butylic acid methyl ester (abbreviation: PC60BM), and 1',1",4',4"-Tetrahydro-di[1,4]methanenaphthaleno[1,2:2',3',56,60:2"3"][5,6]fullerene-C60 (abbreviation: ICBA).

[0187] Examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0188] Examples of the p-type semiconductor material contained in the active layer include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin(II) phthalocyanine (SnPc), and quinacridone.

[0189] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, compounds having an aromatic amine skeleton, etc. Examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, polythiophene derivatives, etc.

[0190] The HOMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the HOMO level of the electron-accepting organic semiconductor material, and the LUMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the LUMO level of the electron-accepting organic semiconductor material.

[0191] It is preferable to use a spherical fullerene as the electron-accepting organic semiconductor material and a planar organic semiconductor material as the electron-donating organic semiconductor material. Molecules with similar shapes tend to aggregate together, and when molecules of the same type aggregate, the energy levels of their molecular orbitals become close, which can improve carrier transport properties.

[0192] For example, the active layer is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor, or may be formed by laminating an n-type semiconductor and a p-type semiconductor.

[0193] The light-receiving device may further include, as a layer other than the active layer, a layer containing a substance with high hole-transporting properties, a substance with high electron-transporting properties, a bipolar substance (a substance with high electron-transporting properties and high hole-transporting properties), etc. Furthermore, without being limited to the above, the light-receiving device may further include a layer containing a substance with high hole-injecting properties, a hole-blocking material, a substance with high electron-injecting properties, an electron-blocking material, etc.

[0194] The light-receiving device may be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. The layers constituting the light-receiving device may be formed by a method such as vapor deposition (including vacuum deposition), transfer, printing, inkjet printing, or coating.

[0195] For example, a polymer compound such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can be used as the hole transport material, and an inorganic compound such as molybdenum oxide or copper iodide (CuI) can be used as the electron transport material.

[0196] Furthermore, a polymer compound such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]] polymer (abbreviated as PBDB-T) or a PBDB-T derivative, which functions as a donor, can be used in the active layer. For example, a method of dispersing an acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0197] The active layer may also contain a mixture of three or more materials. For example, in order to broaden the absorption wavelength range, a third material may be mixed in addition to an n-type semiconductor material and a p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0198] In a display device having a light-emitting device and a light-receiving device in each pixel, the pixel has a light-receiving function, and therefore it is possible to detect contact or proximity of an object while displaying an image. For example, in addition to displaying an image using all of the sub-pixels of the display device, some of the sub-pixels can emit light as a light source, while other sub-pixels can detect light, and the remaining sub-pixels can display an image.

[0199] A display device according to one embodiment of the present invention has a display portion in which light-emitting devices are arranged in a matrix, and can display an image on the display portion. Furthermore, light-receiving devices are arranged in a matrix on the display portion, and the display portion has an imaging function and / or a sensing function in addition to an image display function. The display portion can be used as an image sensor or a touch sensor. That is, by detecting light in the display portion, an image can be captured or the proximity or contact of an object (such as a finger, a hand, or a pen) can be detected. Furthermore, the display device according to one embodiment of the present invention can use a light-emitting device as a light source for a sensor. Therefore, a light-receiving portion and a light source are not required separately from the display device, and the number of components in an electronic device can be reduced.

[0200] In a display device of one embodiment of the present invention, when light emitted from a light-emitting device included in a display portion is reflected (or scattered) by an object, the light-receiving device can detect the reflected light (or scattered light). Therefore, imaging or touch detection is possible even in a dark place.

[0201] When the light receiving device is used as an image sensor, the display device can capture an image using the light receiving device. For example, the display device of the present embodiment can be used as a scanner.

[0202] For example, an image sensor can be used to acquire data related to biometric information such as fingerprints and palm prints. That is, a biometric authentication sensor can be built into the display device. By building a biometric authentication sensor into the display device, the number of components in the electronic device can be reduced compared to when a biometric authentication sensor is provided separately from the display device, and the electronic device can be made smaller and lighter.

[0203] Furthermore, when the light-receiving device is used as a touch sensor, the display device can detect the proximity or contact of an object using the light-receiving device.

[0204] The pixel shown in FIGS. 7A and 7B has subpixels G, B, R, and PS.

[0205] The pixels shown in Fig. 7A are arranged in a stripe pattern, while the pixels shown in Fig. 7B are arranged in a matrix pattern.

[0206] The pixel shown in FIGS. 7C and 7D has subpixels G, B, R, PS, and IRS.

[0207] 7C and 7D show an example in which one pixel is arranged across two rows and three columns. The top row (first row) has three subpixels (subpixel G, subpixel B, and subpixel R). In FIG. 7C , the bottom row (second row) has three subpixels (one subpixel PS and two subpixels IRS). In contrast, in FIG. 7D , the bottom row (second row) has two subpixels (one subpixel PS and one subpixel IRS). As shown in FIG. 7C , by aligning the subpixels in the top row and bottom row, it is possible to efficiently remove dust and other impurities that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided. The subpixel layout is not limited to the configurations shown in FIGS. 7A to 7D .

[0208] Subpixel R has a light-emitting device that emits red light, subpixel G has a light-emitting device that emits green light, and subpixel B has a light-emitting device that emits blue light.

[0209] The subpixels PS and IRS each have a light receiving device. The wavelength of light detected by the subpixels PS and IRS is not particularly limited.

[0210] 7C, the two subpixels IRS may each have an independent light receiving device, or may share one light receiving device. That is, the pixel 110 shown in FIG. 7C may have one light receiving device for the subpixel PS and one or two light receiving devices for the subpixel IRS.

[0211] The light receiving area of ​​the subpixel PS is smaller than the light receiving area of ​​the subpixel IRS. The smaller the light receiving area, the narrower the imaging range, which makes it possible to suppress blurring in the imaging result and improve the resolution. Therefore, by using the subpixel PS, it is possible to perform imaging with higher definition or resolution than when using the subpixel IRS. For example, the subpixel PS can be used to perform imaging for personal authentication using a fingerprint, palm print, iris, pulse shape (including vein shape and artery shape), face, etc.

[0212] The light receiving device included in the subpixel PS preferably detects visible light, and preferably detects one or more of the colors blue, purple, blue-purple, green, yellow-green, yellow, orange, red, etc. The light receiving device included in the subpixel PS may also detect infrared light.

[0213] The sub-pixel IRS can be used as a touch sensor (also called a direct touch sensor) or a near-touch sensor (also called a hover sensor, hover touch sensor, non-contact sensor, or touchless sensor). The wavelength of light to be detected by the sub-pixel IRS can be appropriately determined depending on the application. For example, it is preferable that the sub-pixel IRS detects infrared light. This enables touch detection even in dark places.

[0214] Here, the touch sensor or near-touch sensor can detect the proximity or contact of an object (such as a finger, hand, or pen).

[0215] A touch sensor can detect an object when the display device and the object are in direct contact with each other. A near-touch sensor can detect an object even if the object does not touch the display device. For example, a configuration in which the display device can detect an object when the distance between the display device and the object is between 0.1 mm and 300 mm, preferably between 3 mm and 50 mm, is preferred. This configuration allows the display device to be operated without the object directly touching it, in other words, it allows the display device to be operated in a non-contact (touchless) manner. This configuration reduces the risk of the display device becoming dirty or scratched, or allows the object to operate the display device without directly touching dirt (e.g., dust, viruses, etc.) attached to the display device.

[0216] Furthermore, the display device of one embodiment of the present invention can have a variable refresh rate. For example, the refresh rate can be adjusted (for example, adjusted within a range of 1 Hz to 240 Hz) depending on the content displayed on the display device to reduce power consumption. Furthermore, the drive frequency of the touch sensor or the near-touch sensor may be changed depending on the refresh rate. For example, when the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or the near-touch sensor can be configured to be higher than 120 Hz (typically 240 Hz). This configuration enables low power consumption and an increased response speed of the touch sensor or the near-touch sensor.

[0217] The display device 100 shown in FIGS. 7E to 7G includes a layer 353 having a light-receiving device, a functional layer 355, and a layer 357 having a light-emitting device between a substrate 351 and a substrate 359.

[0218] The functional layer 355 includes a circuit for driving the light-receiving device and a circuit for driving the light-emitting device. The functional layer 355 may be provided with switches, transistors, capacitors, resistors, wiring, terminals, etc. Note that when the light-emitting device and the light-receiving device are driven by a passive matrix method, a configuration without switches and transistors may be used.

[0219] For example, as shown in Fig. 7E , when a finger 352 touches the display device 100, light emitted from a light-emitting device in a layer 357 having a light-emitting device is reflected by the light-receiving device in a layer 353 having a light-receiving device, and the reflected light is detected by the light-receiving device. This makes it possible to detect that the finger 352 has touched the display device 100. Alternatively, as shown in Figs. 7F and 7G , the display device may have a function of detecting or capturing an object that is close to (not in contact with) the display device. Fig. 7F shows an example of detecting a person's finger, and Fig. 7G shows an example of detecting information about the periphery, surface, or interior of a person's eye (such as the number of blinks, eyeball movement, and eyelid movement).

[0220] By mounting two types of light receiving devices in one pixel, two functions can be added in addition to the display function, making it possible to multi-function the display device.

[0221] In order to capture high-resolution images, it is preferable that the sub-pixels PS be provided in all pixels of the display device. On the other hand, the sub-pixels IRS used in touch sensors or near-touch sensors do not require higher accuracy than detection using the sub-pixels PS, so they may be provided in only some of the pixels of the display device. By making the number of sub-pixels IRS in the display device smaller than the number of sub-pixels PS, the detection speed can be increased.

[0222] As described above, by incorporating two types of light-receiving devices into one pixel, the display device of one embodiment of the present invention can add two functions in addition to a display function, thereby enabling the display device to have multiple functions. For example, a high-resolution imaging function and a sensing function such as a touch sensor or a near-touch sensor can be realized. Furthermore, by combining a pixel incorporating two types of light-receiving devices with a pixel having a different configuration, the functions of the display device can be further increased. For example, a pixel including a light-emitting device that emits infrared light or various sensor devices can be used.

[0223] [Example of Manufacturing Method of Display Device] Next, an example of a manufacturing method of a display device will be described with reference to Fig. 8 to Fig. 14. Fig. 8A to Fig. 8C are top views showing a manufacturing method of a display device. Fig. 9A to Fig. 9C show cross-sectional views taken along dashed dotted lines X1-X2 and Y1-Y2 in Fig. 1A side by side. Fig. 10 to Fig. 13 are similar to Fig. 9. Fig. 14A to Fig. 14E show cross-sectional views taken along dashed dotted lines X1-X2 in Fig. 1A.

[0224] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using a sputtering method, a chemical vapor deposition (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 chemical vapor deposition (MOCVD) method.

[0225] 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.

[0226] 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 devices. 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 included in the EL layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) can be formed by 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.

[0227] Furthermore, when processing the thin film that constitutes the display device, a photolithography method or the like can be used. Alternatively, the thin film may be processed by 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.

[0228] 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.

[0229] In photolithography, the light used for exposure may 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 may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays may also be used as the light used for exposure. An electron beam may 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.

[0230] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0231] First, as shown in FIG. 9A, a conductive film 111 is formed over a layer 101 including a transistor.

[0232] Then, a first light-emitting unit 181A, a charge generation layer 182A, and a second light-emitting unit 183A are formed in this order on the conductive film 111, a first sacrificial layer 118A is formed on the second light-emitting unit 183A, and a second sacrificial layer 119A is formed on the first sacrificial layer 118A.

[0233] 9A , in the cross-sectional view between Y1 and Y2, the ends of the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A on the connection portion 140 side are located inside the end of the first sacrificial layer 118A. For example, by using a mask for defining the film formation area (also referred to as an area mask or a rough metal mask to distinguish it from a fine metal mask), the regions where the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A are formed, and the regions where the first sacrificial layer 118A and the second sacrificial layer 119A are formed can be varied. In one embodiment of the present invention, a light-emitting device is formed using a resist mask. However, by combining the resist mask with an area mask as described above, a light-emitting device can be manufactured by a relatively simple process.

[0234] The conductive film 111 is a layer that will be processed later to become the pixel electrodes 111a, 111b, and 111c and the conductive layer 123. Therefore, the structure applicable to the pixel electrodes described above can be applied to the conductive film 111. The conductive film 111 can be formed by, for example, sputtering or vacuum evaporation.

[0235] The first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A are layers that will later become the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a, respectively. Therefore, the above-described structures applicable to the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a can be applied to each of them. The first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be formed by a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like. Each layer is preferably formed by a vapor deposition method. A premixed material may be used for film formation using a vapor deposition method. In this specification and the like, a premixed material refers to a composite material in which multiple materials are blended or mixed in advance.

[0236] For the first sacrificial layer 118A and the second sacrificial layer 119A, a film having high resistance to processing conditions for the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A, as well as the first light-emitting unit 181B, the charge generation layer 182B, the second light-emitting unit 183B, the first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C to be formed in a later step, specifically a film having a large etching selectivity with respect to various EL layers, is used.

[0237] The first sacrificial layer 118A and the second sacrificial layer 119A can be formed by, for example, sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum evaporation. The first sacrificial layer 118A, which is formed on and in contact with the EL layer, is preferably formed using a method that causes less damage to the EL layer than the second sacrificial layer 119A. For example, the first sacrificial layer 118A is preferably formed using ALD or vacuum evaporation rather than sputtering. The first sacrificial layer 118A and the second sacrificial layer 119A are formed at a temperature lower than the heat-resistant temperature limit of the EL layer (typically, 200° C. or lower, preferably 100° C. or lower, and more preferably 80° C. or lower).

[0238] It is preferable to use a film that can be removed by wet etching for the first sacrificial layer 118A and the second sacrificial layer 119A. By using wet etching, damage to the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A can be reduced compared to when dry etching is used.

[0239] It is also preferable to use a film for the first sacrificial layer 118A that has a large etching selectivity with respect to the second sacrificial layer 119A.

[0240] In the process of processing the various sacrificial layers in the manufacturing method of the display device of this embodiment, it is desirable that the layers constituting the EL layer (such as the hole injection layer, the hole transport layer, the light-emitting layer, and the electron transport layer) are not easily processed, and that the various sacrificial layers are not easily processed in the process of processing the layers constituting the EL layer. It is desirable to select the material and processing method of the sacrificial layer and the processing method of the EL layer taking these factors into consideration.

[0241] In this embodiment, an example is shown in which the sacrificial layer is formed with a two-layer structure of a first sacrificial layer and a second sacrificial layer, but the sacrificial layer may have a single-layer structure or a stacked structure of three or more layers.

[0242] The first sacrificial layer 118A and the second sacrificial layer 119A can each be made of, 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.

[0243] The first sacrificial layer 118A and the second sacrificial layer 119A can be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy material containing such a metal material. In particular, it is preferable to use a low-melting-point material such as aluminum or silver. Using a metal material capable of blocking ultraviolet light for one or both of the first sacrificial layer 118A and the second sacrificial layer 119A can prevent the EL layer from being exposed to ultraviolet light, thereby suppressing deterioration of the EL layer.

[0244] The first sacrificial layer 118A and the second sacrificial layer 119A can be made of a metal oxide such as In—Ga—Zn oxide. For example, an In—Ga—Zn oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A by sputtering. Other examples include indium oxide, In—Zn oxide, In—Sn oxide, indium titanium oxide (In—Ti oxide), indium tin zinc oxide (In—Sn—Zn oxide), indium titanium zinc oxide (In—Ti—Zn oxide), and indium gallium tin zinc oxide (In—Ga—Sn—Zn oxide). Alternatively, indium tin oxide containing silicon can be used.

[0245] In addition, instead of the above gallium, an element M (M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used.

[0246] Furthermore, the first sacrificial layer 118A and the second sacrificial layer 119A can be made of any of the various inorganic insulating films that can be used for the protective layers 131 and 132. In particular, oxide insulating films are preferable because they have higher adhesion to the EL layer than nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the first sacrificial layer 118A and the second sacrificial layer 119A. For example, an aluminum oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A by the ALD method. The ALD method is preferable because it can reduce damage to the underlying layer (particularly the EL layer).

[0247] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed by ALD can be used as the first sacrificial layer 118A, and an In—Ga—Zn oxide film formed by sputtering can be used as the second sacrificial layer 119A. Alternatively, an inorganic insulating film (e.g., an aluminum oxide film) formed by ALD can be used as the first sacrificial layer 118A, and an aluminum film or tungsten film formed by sputtering can be used as the second sacrificial layer 119A.

[0248] The first sacrificial layer 118A and the second sacrificial layer 119A may be made of a material that is soluble in a solvent that is chemically stable with respect to at least the film located at the top of the second light-emitting unit 183A. In particular, a material that dissolves in water or alcohol is preferably used for the first sacrificial layer 118A or the second sacrificial layer 119A. When forming a film of such a material, it is preferable to apply the material dissolved in a solvent such as water or alcohol by a wet film formation method, and then perform a heat treatment to evaporate the solvent. In this case, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature in a short time, thereby reducing thermal damage to the EL layer.

[0249] The first sacrificial layer 118A and the second sacrificial layer 119A may be formed using a wet film formation method such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0250] The first sacrificial layer 118A and the second sacrificial layer 119A may be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0251] 9B, a resist mask 190a is formed on the second sacrificial layer 119A. The resist mask can be formed by applying a photosensitive resin (photoresist) and then performing exposure and development.

[0252] The resist mask may be made of either a positive resist material or a negative resist material.

[0253] 8A, the resist mask 190a is provided in a position that overlaps with an area that will later become the sub-pixel 110a. Preferably, the resist mask 190a has an island-shaped pattern for each sub-pixel 110a. Alternatively, the resist mask 190a may have a strip-shaped pattern for multiple sub-pixels 110a that are aligned in a line (aligned in the Y direction in FIG. 8A).

[0254] Note that the resist mask 190a is preferably provided also in a position overlapping with a region that will later become the connection portion 140. This can prevent the region of the conductive film 111 that will later become the conductive layer 123 from being damaged during the manufacturing process of the display device.

[0255] 9C , a resist mask 190a is used to remove a portion of the second sacrificial layer 119A to form a second sacrificial layer 119a. The second sacrificial layer 119a remains in a region that will later become the subpixel 110a and a region that will later become the connection portion 140.

[0256] When etching the second sacrificial layer 119A, it is preferable to use etching conditions with a high selectivity so that the first sacrificial layer 118A is not removed by the etching. Furthermore, since the EL layer is not exposed when processing the second sacrificial layer 119A, the range of processing methods available is wider than when processing the first sacrificial layer 118A. Specifically, even when a gas containing oxygen is used as an etching gas when processing the second sacrificial layer 119A, deterioration of the EL layer can be further suppressed.

[0257] Thereafter, the resist mask 190a is removed. For example, the resist mask 190a can be removed by ashing using oxygen plasma. Alternatively, the resist mask 190a can be removed by ashing using oxygen gas and CF ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ Alternatively, a noble gas (also referred to as a rare gas) such as He may be used. Alternatively, the resist mask 190a may be removed by wet etching. At this time, the first sacrificial layer 118A is located on the outermost surface, and the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A are not exposed. Therefore, damage to the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be suppressed in the process of removing the resist mask 190a. Furthermore, the range of options for removing the resist mask 190a can be expanded.

[0258] Next, as shown in FIG. 10A, the second sacrificial layer 119a is used as a hard mask to remove a portion of the first sacrificial layer 118A, thereby forming a first sacrificial layer 118a.

[0259] The first sacrificial layer 118A and the second sacrificial layer 119A can be processed by wet etching or dry etching, respectively. The first sacrificial layer 118A and the second sacrificial layer 119A are preferably processed by anisotropic etching.

[0260] Compared to the case of using dry etching, using wet etching can reduce damage to first light-emitting unit 181A, charge generation layer 182A, and second light-emitting unit 183A during processing of first sacrificial layer 118A and second sacrificial layer 119A. When using wet etching, it is preferable to use a chemical solution such as a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0261] When dry etching is used, deterioration of the first light-emitting unit 181A, the charge generating layer 182A, and the second light-emitting unit 183A can be suppressed by not using a gas containing oxygen as the etching gas. ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing a noble gas (also called a rare gas) such as He or the like as an etching gas.

[0262] For example, when an aluminum oxide film formed by ALD is used as the first sacrificial layer 118A, CHF ３ The first sacrificial layer 118A can be processed by dry etching using He. When an In-Ga-Zn oxide film formed by sputtering is used as the second sacrificial layer 119A, the second sacrificial layer 119A can be processed by wet etching using diluted phosphoric acid. ４ The second sacrificial layer 119A may be processed by dry etching using Ar and diluted phosphoric acid. Alternatively, the second sacrificial layer 119A may be processed by wet etching using diluted phosphoric acid. When a tungsten film formed by sputtering is used as the second sacrificial layer 119A, CF ４ and O ２ , or CF ４ and Cl ２ and O ２The second sacrificial layer 119A can be processed by dry etching using the above.

[0263] Next, as shown in FIG. 10B, the second sacrificial layer 119a and the first sacrificial layer 118a are used as hard masks to remove a portion of the first light-emitting unit 181A, a portion of the charge generation layer 182A, and a portion of the second light-emitting unit 183A, thereby forming the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a.

[0264] 10B , in a region corresponding to the subpixel 110a, a stacked structure of the first light-emitting unit 181a, the charge generation layer 182a, the second light-emitting unit 183a, the first sacrificial layer 118a, and the second sacrificial layer 119a remains on the conductive film 111. Note that the stacked structure of the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a is also referred to as the first layer 113a. Furthermore, in a region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a and the second sacrificial layer 119a remains on the conductive film 111.

[0265] By the above process, the regions of the first light-emitting unit 181A, the charge generation layer 182A, the second light-emitting unit 183A, the first sacrificial layer 118A, and the second sacrificial layer 119A that do not overlap with the resist mask 190a can be removed.

[0266] Note that the resist mask 190a may be used to remove part of the first light-emitting unit 181A, part of the charge generation layer 182A, and part of the second light-emitting unit 183A, and then the resist mask 190a may be removed.

[0267] Alternatively, the process may proceed to the next step without removing the resist mask 190a. In this case, when processing the conductive film 111 in a later step, not only the sacrificial layer but also the resist mask can be used as a mask. Processing the conductive film 111 using the resist masks 190a, 190b, and 190c may make the conductive film 111 easier to process than when only the sacrificial layer is used as a hard mask. For example, the range of options for the processing conditions of the conductive film 111, the material of the sacrificial layer, or the material of the conductive film can be expanded.

[0268] The first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A are preferably processed by anisotropic etching. Anisotropic dry etching is particularly preferable. Alternatively, wet etching may be used.

[0269] When dry etching is used, deterioration of the first light-emitting unit 181A, the charge generating layer 182A, and the second light-emitting unit 183A can be suppressed by not using a gas containing oxygen as the etching gas.

[0270] Alternatively, a gas containing oxygen may be used as the etching gas. The inclusion of oxygen in the etching gas can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate. This can reduce damage to the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A. Furthermore, problems such as adhesion of reaction products that occur during etching can be reduced.

[0271] When dry etching is used, for example, H ２ , C.F. ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing one or more of the following gases as the etching gas: H, Ar, or a noble gas (also called a rare gas). Alternatively, it is preferable to use a gas containing one or more of these gases and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas. Specifically, for example, H ２ and a gas containing Ar, or CF ４ A gas containing CF and He can be used as an etching gas. ４ A gas containing He and oxygen can be used as the etching gas.

[0272] Next, as shown in FIG. 10C, a first light-emitting unit 181B, a charge generation layer 182B, and a second light-emitting unit 183B are formed in this order on the second sacrificial layer 119a and the conductive film 111, a first sacrificial layer 118B is formed on the second light-emitting unit 183B, and a second sacrificial layer 119B is formed on the first sacrificial layer 118B.

[0273] As shown in Figure 10C, in the cross-sectional view between Y1 and Y2, the ends of the first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B on the connection portion 140 side are located inside the ends of the first sacrificial layer 118B.

[0274] The first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B are layers that will later become the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b, respectively. The first light-emitting unit 181b and the second light-emitting unit 183b emit light of different colors from the first light-emitting unit 181a and the second light-emitting unit 183a, respectively. The structures, materials, etc. that can be applied to the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b are similar to those of the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a, respectively. The first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B can be formed using the same methods as the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A, respectively.

[0275] The first sacrificial layer 118B can be formed using a material that can be used for the first sacrificial layer 118A. The second sacrificial layer 119B can be formed using a material that can be used for the second sacrificial layer 119A.

[0276] Next, as shown in FIG. 10C, a resist mask 190b is formed on the second sacrificial layer 119B.

[0277] 8B , the resist mask 190b is provided in a position that overlaps with an area that will later become the sub-pixel 110b. Preferably, the resist mask 190b has an island-shaped pattern for each sub-pixel 110b. Alternatively, the resist mask 190b may have a strip-shaped pattern for a plurality of sub-pixels 110b that are arranged in a row.

[0278] The resist mask 190b may also be provided at a position that overlaps with the region that will later become the connection portion 140.

[0279] Next, a resist mask 190b is used to remove a portion of the second sacrificial layer 119B to form a second sacrificial layer 119b, which remains in the region that will later become the sub-pixel 110b.

[0280] Thereafter, the resist mask 190b is removed, and then, using the second sacrificial layer 119b as a hard mask, a part of the first sacrificial layer 118B is removed to form a first sacrificial layer 118b.

[0281] Then, as shown in FIG. 11A, using the second sacrificial layer 119b and the first sacrificial layer 118b as a hard mask, a portion of the first light-emitting unit 181B, a portion of the charge generation layer 182B, and a portion of the second light-emitting unit 183B are removed to form the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b.

[0282] 11A , in a region corresponding to the subpixel 110b, a stacked structure of the first light-emitting unit 181b, the charge generation layer 182b, the second light-emitting unit 183b, the first sacrificial layer 118b, and the second sacrificial layer 119b remains on the conductive film 111. Note that the stacked structure of the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b is also referred to as the second layer 113b. Furthermore, in a region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a and the second sacrificial layer 119a remains on the conductive film 111.

[0283] Through the above steps, regions of the first light-emitting unit 181B, the charge generation layer 182B, the second light-emitting unit 183B, the first sacrificial layer 118B, and the second sacrificial layer 119B that do not overlap with the resist mask 190b can be removed. These layers can be processed using a method that can be applied to processing the first light-emitting unit 181A, the charge generation layer 182A, the second light-emitting unit 183A, the first sacrificial layer 118A, and the second sacrificial layer 119A.

[0284] Next, as shown in FIG. 11B, a first light-emitting unit 181C, a charge generation layer 182C, and a second light-emitting unit 183C are formed in this order on the second sacrificial layer 119a, the second sacrificial layer 119b, and the conductive film 111, a first sacrificial layer 118C is formed on the second light-emitting unit 183C, and a second sacrificial layer 119C is formed on the first sacrificial layer 118C.

[0285] As shown in Figure 11B, in the cross-sectional view between Y1 and Y2, the ends of the first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C on the connection portion 140 side are located more inward than the end of the first sacrificial layer 118C.

[0286] The first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C are layers that will later become the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c, respectively. The first light-emitting unit 181c and the second light-emitting unit 183c emit light of a different color from the first light-emitting units 181a and 181b and the second light-emitting units 183a and 183b, respectively. The structures, materials, and the like that can be applied to the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c are similar to those of the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a, respectively. The first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C can be formed using the same methods as the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A, respectively.

[0287] The first sacrificial layer 118C can be formed using a material that can be used for the first sacrificial layer 118A. The second sacrificial layer 119C can be formed using a material that can be used for the second sacrificial layer 119A.

[0288] Next, as shown in FIG. 11B, a resist mask 190c is formed on the second sacrificial layer 119C.

[0289] 8C , the resist mask 190c is provided in a position that overlaps with an area that will later become the sub-pixel 110c. Preferably, the resist mask 190c has an island-shaped pattern for each sub-pixel 110c. Alternatively, the resist mask 190c may have a strip-shaped pattern for a plurality of sub-pixels 110c arranged in a row.

[0290] The resist mask 190c may also be provided at a position that overlaps with the region that will later become the connection section 140.

[0291] Next, a resist mask 190c is used to remove a portion of the second sacrificial layer 119C to form a second sacrificial layer 119c, which remains in a region that will later become the sub-pixel 110c.

[0292] Thereafter, the resist mask 190c is removed. Then, using the second sacrificial layer 119c as a hard mask, a part of the first sacrificial layer 118C is removed to form a first sacrificial layer 118c.

[0293] Then, as shown in FIG. 11C, the second sacrificial layer 119c and the first sacrificial layer 118c are used as hard masks to remove a portion of the first light-emitting unit 181C, a portion of the charge generation layer 182C, and a portion of the second light-emitting unit 183C, thereby forming the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c.

[0294] 11C , in a region corresponding to the subpixel 110c, a stacked structure of the first light-emitting unit 181c, the charge generation layer 182c, the second light-emitting unit 183c, the first sacrificial layer 118c, and the second sacrificial layer 119c remains on the conductive film 111. Note that the stacked structure of the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c is also referred to as a third layer 113c. Furthermore, in a region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a and the second sacrificial layer 119a remains on the conductive film 111.

[0295] Through the above steps, regions of the first light-emitting unit 181C, the charge generation layer 182C, the second light-emitting unit 183C, the first sacrificial layer 118C, and the second sacrificial layer 119C that are not overlapped with the resist mask 190c can be removed. These layers can be processed using a method that can be applied to processing the first light-emitting unit 181A, the charge generation layer 182A, the second light-emitting unit 183A, the first sacrificial layer 118A, and the second sacrificial layer 119A.

[0296] The side surfaces of the light-emitting units and the charge generating layer are preferably perpendicular or approximately perpendicular to the surface on which they are formed. For example, the angle between the surface on which they are formed and the side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0297] Next, as shown in FIG. 12A, the conductive film 111 is processed using the first sacrificial layers 118a, 118b, and 118c and the second sacrificial layers 119a, 119b, and 119c as hard masks to form pixel electrodes 111a, 111b, and 111c and a conductive layer 123.

[0298] Note that sidewalls covering the respective side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may be formed before processing the conductive film 111. This can suppress damage to the first layer 113a, the second layer 113b, and the third layer 113c in the process of processing the conductive film 111.

[0299] When the conductive film 111 is processed, a part of the transistor-including layer 101 (specifically, the insulating layer located at the outermost surface) may be processed to form a recess. In the following description, a case where a recess is provided in the transistor-including layer 101 will be described as an example, but the recess may not be provided.

[0300] Here, in order to form the conductive layer 123, it is preferable that any one of the first sacrificial layers 118a, 118b, and 118c and any one of the second sacrificial layers 119a, 119b, and 119c are provided in the connection portion 140. Any two or all of the first sacrificial layers 118a, 118b, and 118c and any two or all of the second sacrificial layers 119a, 119b, and 119c may be provided in the connection portion 140. By providing the sacrificial layer in the connection portion 140, a region of the conductive film 111 that will become the conductive layer 123 can be prevented from being damaged during the manufacturing process of the display device. Therefore, it is preferable to form the first sacrificial layer 118a and the second sacrificial layer 119a, which are manufactured earliest.

[0301] The conductive film 111 can be processed by a wet etching method or a dry etching method. The conductive film 111 is preferably processed by anisotropic etching.

[0302] Next, as shown in FIG. 12B, an insulating film 125A is formed so as to cover the pixel electrodes 111a, 111b, and 111c, the first layer 113a, the second layer 113b, the third layer 113c, the first sacrificial layers 118a, 118b, and 118c, and the second sacrificial layers 119a, 119b, and 119c, and an insulating film 125B is formed on the insulating film 125A.

[0303] The insulating films 125A and 125B can each be made of 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 magnesium oxide film, a gallium oxide film, a germanium oxide film, a 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.

[0304] The insulating films 125A and 125B are preferably formed by a method that causes less damage to the EL layer. In particular, since the insulating film 125A is formed in contact with the side surface of the EL layer, it is preferably formed by a method that causes less damage to the EL layer than the insulating film 125B. Furthermore, the insulating films 125A and 125B are each formed at a temperature lower than the heat resistance temperature of the EL layer (typically 200°C or lower, preferably 100°C or lower, and more preferably 80°C or lower). For example, an aluminum oxide film can be formed as the insulating film 125A by the ALD method. The ALD method is preferable because it can reduce film damage and form a film with high coverage. Furthermore, for example, a silicon oxynitride film or a silicon nitride film can be formed as the insulating film 125B by the sputtering method, the CVD method, or the PECVD method. These methods have a faster film formation rate than the ALD method, thereby increasing productivity. Furthermore, the insulating film 125B is preferably thicker than the insulating film 125A.

[0305] One or both of the insulating films 125A and 125B preferably function as a barrier insulating film against at least one of water and oxygen. Alternatively, one or both of the insulating films 125A and 125B preferably have a function of suppressing diffusion of at least one of water and oxygen. Alternatively, one or both of the insulating films 125A and 125B preferably have a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0306] 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).

[0307] One or both of the insulating films 125A and 125B have the above-mentioned barrier insulating film function or gettering function, which makes it possible to suppress the intrusion of impurities (typically water or oxygen) that can diffuse into each light-emitting device from the outside. With this configuration, it is possible to provide a display device with excellent reliability.

[0308] Next, as shown in FIG. 12C , the insulating films 125A and 125B are processed to form sidewalls 125a and 125b. The sidewalls 125b are formed so as to contact the upper and side surfaces of the sidewall 125a. The sidewalls 125a and 125b are provided so as to cover the side surfaces of the pixel electrodes 111a, 111b, and 111c. This prevents a film (a film constituting an EL layer or a common electrode) to be formed later from contacting the pixel electrodes 111a, 111b, and 111c, thereby preventing a short circuit in the light-emitting device. Furthermore, the sidewalls 125a and 125b are preferably provided so as to cover the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c. This prevents a film to be formed later from contacting the side surfaces of these layers, thereby preventing a short circuit in the light-emitting device. Furthermore, damage to the first layer 113a, the second layer 113b, and the third layer 113c in subsequent steps can be suppressed.

[0309] In particular, it is preferable to provide a recess in a part of the layer 101 including the transistor (specifically, in the insulating layer located on the outermost surface), because this makes it possible to cover the entire side surfaces of the pixel electrodes 111a, 111b, and 111c with the sidewalls 125a and 125b.

[0310] The insulating films 125A and 125B are preferably processed by dry etching. The insulating films 125A and 125B are preferably processed by anisotropic etching. The insulating films 125A and 125B can be processed using an etching gas that can be used to process the first sacrificial layer 118A and the second sacrificial layer 119A. Furthermore, since the EL layer is not exposed when processing the insulating films 125A and 125B, the range of processing methods available is wider than when processing the first sacrificial layer 118A. Specifically, even when a gas containing oxygen is used as an etching gas when processing the insulating film 125A or 125B, deterioration of the EL layer can be further suppressed.

[0311] The end of the sidewall 125b may be rounded. For example, when forming the insulating film 125B, if the upper portion of the insulating film 125B is etched by anisotropic etching using a dry etching method, the end of the sidewall 125b will be rounded as shown in FIG. 12C . Rounding the end of the sidewall 125b is preferable because it improves coverage with the fifth layer 114 or the common electrode 115 to be formed later. As shown in FIG. 12B , making the thickness of the insulating film 125B thicker than the thickness of the insulating film 125A may make it easier to round the end of the sidewall 125b.

[0312] Although an example in which the sidewall is formed with a two-layer structure is shown here, the sidewall may have a single-layer structure or a laminated structure of three or more layers.

[0313] 13A , the first sacrificial layers 118a, 118b, and 118c and the second sacrificial layers 119a, 119b, and 119c are removed, thereby exposing the first layer 113a on the pixel electrode 111a, the second layer 113b on the pixel electrode 111b, the third layer 113c on the pixel electrode 111c, and the conductive layer 123 at the connection portion 140.

[0314] The sacrificial layer removal step can be performed using a method similar to that used in the sacrificial layer processing step. In particular, by using a wet etching method, damage to the first layer 113 a, the second layer 113 b, and the third layer 113 c can be reduced compared to when a dry etching method is used.

[0315] The first sacrificial layer and the second sacrificial layer may be removed in separate steps or in the same step.

[0316] Alternatively, one or both of the first and second sacrificial layers may be removed by dissolving them in a solvent such as water or alcohol, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0317] After removing the first sacrificial layer and the second sacrificial layer, a drying treatment may be performed to remove water contained in the EL layer and water adsorbed on the surface of the EL layer. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0318] Next, as shown in Fig. 13B, a fifth layer 114 is formed to cover the sidewalls 125a, 125b, the first layer 113a, the second layer 113b, and the third layer 113c. As shown in Fig. 13B, in the cross-sectional view between Y1 and Y2, the end of the fifth layer 114 on the connection portion 140 side is located inside the connection portion 140, and the conductive layer 123 remains exposed. Note that, as shown in Fig. 13C, depending on the level of conductivity of the fifth layer 114, the fifth layer 114 may be provided at the connection portion 140.

[0319] The materials that can be used for the fifth layer 114 are as described above. The fifth 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. The fifth layer 114 may also be formed using a premixed material.

[0320] The fifth layer 114 is provided to cover the sidewall 125a, the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, and the top surface and side surfaces of the sidewall 125b. If the fifth layer 114 has high conductivity, contact between the fifth layer 114 and any of the pixel electrodes 111a, 111b, and 111c may cause a short circuit in the light-emitting device. However, in the display device of one embodiment of the present invention, the sidewalls 125a and 125b cover the first layer 113a, the second layer 113b, the third layer 113c, and the side surfaces of the pixel electrodes 111a, 111b, and 111c. This prevents the highly conductive fifth layer 114 from contacting these layers, thereby preventing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0321] Then, as shown in FIG. 13B, a common electrode 115 is formed on the fifth layer 114 and the conductive layer 123 .

[0322] A mask for defining a film formation area may be used when forming the common electrode 115. Alternatively, the mask may not be used when forming the common electrode 115, and the common electrode 115 may be processed using a resist mask or the like after the common electrode 115 is formed.

[0323] The materials that can be used for the common electrode 115 are as described above. The common electrode 115 can be formed by, for example, sputtering or vacuum deposition. Alternatively, a film formed by deposition and a film formed by sputtering may be stacked.

[0324] 14A , a gap 134 may be formed in a region between the side surfaces (between the sidewalls 125 b) of two opposing EL layers and in a recess of the transistor-including layer 101. Specifically, in FIG. 14A , the gap 134 is surrounded by the transistor-including layer 101, the sidewalls 125 a and 125 b, and the fifth layer 114.

[0325] As described above, a void 134 may exist in the region between the side surfaces of two opposing EL layers and in the recessed portion of the transistor-including layer 101. Depending on the distance between adjacent EL layers, the thickness of the fifth layer 114, the thickness of the common electrode 115, the thickness of the protective layer 131, and the like, the void may not be formed. In this case, the region between the side surfaces of two opposing EL layers and the recessed portion of the transistor-including layer 101 are filled with at least one of the fifth layer 114, the common electrode 115, and the protective layer 131. Alternatively, an insulating material may be filled into the region that could become a void.

[0326] The void 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 in forming the fifth layer 114 or the like. For example, when the fifth layer 114 is formed by vacuum deposition, the void may be in a reduced pressure atmosphere. When the void contains a gas, the gas can be identified by gas chromatography or the like.

[0327] Furthermore, when the refractive index of the void is lower than that of the fifth layer 114, the common electrode 115, or the protective layer 131, light emitted from the first layer 113a, the second layer 113b, or the third layer 113c is reflected at the interface between the fifth layer 114, the common electrode 115, or the protective layer 131 and the void. This prevents light emitted from the first layer 113a, the second layer 113b, or the third layer 113c from entering an adjacent pixel (or subpixel). This prevents light of different colors from mixing, thereby improving the display quality of the display device.

[0328] 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.

[0329] Examples of organic insulating materials 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 122 may be used.

[0330] 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.

[0331] 14B , the fifth layer 114 may be omitted, and the common electrode 115 may be formed to cover the sidewalls 125 a, 125 b, the first layer 113 a, the second layer 113 b, and the third layer 113 c. In other words, all layers constituting the EL layer may be formed separately for each light-emitting device that emits light of a different color. In this case, the EL layer of each light-emitting device is formed in an island shape.

[0332] Here, contact between any of the pixel electrodes 111a, 111b, and 111c and the common electrode 115 may cause a short circuit in the light-emitting device. However, in the display device of one embodiment of the present invention, the sidewalls 125a and 125b cover the side surfaces of the first layer 113a, the second layer 113b, the third layer 113c, and the pixel electrodes 111a, 111b, and 111c. This prevents the common electrode 115 from contacting these layers, thereby preventing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0333] 14B shows an example in which the common electrode 115 is embedded in the region between the light-emitting devices (between the sidewalls 125b) and even in the recess of the transistor-containing layer 101. Alternatively, as shown in FIG. 14A, a gap 134 may be provided.

[0334] As described above, the shape of the layer formed after the sidewalls 125 a and 125 b are not particularly limited and may vary depending on the material, deposition method, film thickness, etc. The display device of one embodiment of the present invention has the sidewalls 125 a and 125 b, which suppresses short circuits in the light-emitting device. Therefore, the range of options for the material, deposition method, and film thickness of the layer formed after the sidewalls 125 a and 125 b are broadened.

[0335] 14C, a single-layer sidewall 125 may be provided. The sidewall 125 may be made of the same material and formed by the same method as those for the sidewalls 125a and 125b.

[0336] Furthermore, as shown in FIG. 14D, when processing the insulating film 125A, a part of the layer 101 including the transistor (specifically, the insulating layer located on the outermost surface) may be processed, and a recess may be formed.

[0337] Furthermore, as shown in FIG. 14E, if a portion of the layer 101 including the transistor (specifically, the insulating layer located on the outermost surface) is not processed during processing of the conductive film 111, a recess may not be formed in the layer 101 including the transistor.

[0338] Thereafter, a protective layer 131 is formed on the common electrode 115, and a protective layer 132 is formed on the protective layer 131. Furthermore, by using a resin layer 122, a substrate 120 is bonded onto the protective layer 132, whereby the display device 100 shown in FIG.

[0339] The materials and film formation methods that can be used for the protective layers 131 and 132 are as described above. Examples of film formation methods for the protective layers 131 and 132 include vacuum deposition, sputtering, CVD, and ALD. The protective layers 131 and 132 may be films formed using different film formation methods. Furthermore, the protective layers 131 and 132 may each have a single-layer structure or a multilayer structure.

[0340] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is formed by forming the EL layer on the entire surface and then processing it, rather than by using a fine metal mask, so that the island-shaped EL layer can be formed with a uniform thickness, and a high-definition display device or a display device with a high aperture ratio can be realized.

[0341] The first, second, and third layers constituting the light-emitting device of each color are formed in separate processes. Therefore, each EL layer can be fabricated with a configuration (material, film thickness, etc.) suitable for the light-emitting device of each color. This allows the fabrication of light-emitting devices with excellent characteristics.

[0342] A display device according to one embodiment of the present invention has sidewalls covering the respective side surfaces of the pixel electrode, the light-emitting layer, and the carrier transport layer. In a manufacturing process of the display device, the EL layer is processed in a state in which 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 a short circuit of the light-emitting device.

[0343] 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.

[0344] Embodiment 2 In this embodiment, a structural example of a light-emitting device that can be applied to a display device of one embodiment of the present invention will be described with reference to FIGS.

[0345] The display device 500 shown in FIGS. 15A to 15C includes a light emitting device 550R that emits red light, a light emitting device 550G that emits green light, and a light emitting device 550B that emits blue light.

[0346] 15A and 15B includes a light-emitting unit 512R_1 between a pair of electrodes (electrode 501 and electrode 502). Similarly, a light-emitting device 550G includes a light-emitting unit 512G_1, and a light-emitting device 550B includes a light-emitting unit 512B_1.

[0347] That is, each of the light emitting devices 550R, 550G, and 550B shown in FIGS. 15A and 15B is a light emitting device having a single structure and including one light emitting unit.

[0348] 15C has a configuration in which two light-emitting units (light-emitting unit 512R_1 and light-emitting unit 512R_2) are stacked between a pair of electrodes (electrode 501 and electrode 502) via a charge generation layer 531. Similarly, light-emitting device 550G has light-emitting units 512G_1 and 512G_2, and light-emitting device 550B has light-emitting units 512B_1 and 512B_2.

[0349] That is, the light emitting devices 550R, 550G, and 550B shown in FIG. 15C are each light emitting devices with a tandem structure having two light emitting units.

[0350] A configuration in which multiple light-emitting units are connected in series via a charge generation layer 531, such as light-emitting device 550R, light-emitting device 550G, and light-emitting device 550B shown in FIG. 15C, is referred to as a tandem structure in this specification. On the other hand, a configuration in which one light-emitting unit is located between a pair of electrodes, such as light-emitting devices 550R, 550G, and 550B shown in FIGS. 15A and 15B, is referred to as a single structure. Although the term "tandem structure" is used in this specification and the like, this is not limiting; for example, the tandem structure may also be referred to as a "stack structure." The tandem structure allows for a light-emitting device capable of emitting light with high brightness. Furthermore, the tandem structure can reduce the current required to achieve the same brightness compared to a single structure, thereby improving reliability.

[0351] Furthermore, a structure in which a separate light-emitting layer is formed for each light-emitting device, such as the display device 500 shown in FIGS. 15A to 15C, is sometimes called an SBS (Side By Side) structure.

[0352] The display device 500 shown in FIG. 15C has light-emitting devices with a tandem structure and can be considered to have an SBS structure. Therefore, it can combine the advantages of both a tandem structure and an SBS structure. The display device 500 shown in FIG. 15C may also be referred to as a two-tier tandem structure because the light-emitting units are formed in two tiers in series. The two-tier tandem structure of the light-emitting device 550R shown in FIG. 15C is structured such that a second light-emitting unit having a red light-emitting layer is stacked on top of a first light-emitting unit having a red light-emitting layer. Similarly, the two-tier tandem structure of the light-emitting device 550G shown in FIG. 15C is structured such that a second light-emitting unit having a green light-emitting layer is stacked on top of a first light-emitting unit having a green light-emitting layer. The two-tier tandem structure of the light-emitting device 550B is structured such that a second light-emitting unit having a blue light-emitting layer is stacked on top of a first light-emitting unit having a blue light-emitting layer.

[0353] The electrode 501 functions as a pixel electrode and is provided for each light-emitting device, while the electrode 502 functions as a common electrode and is provided in common to a plurality of light-emitting devices.

[0354] The light-emitting unit has at least one light-emitting layer. The light-emitting unit may have any number of light-emitting layers, and may have one, two, three, four or more light-emitting layers.

[0355] The light-emitting unit 512R_1 includes a layer 521, a layer 522, a light-emitting layer 523R, a layer 524, and the like. FIG. 15A shows an example in which the light-emitting unit 512R_1 includes a layer 525, and FIG. 15B shows an example in which the light-emitting unit 512R_1 does not include the layer 525, and the layer 525 is provided in common among the light-emitting devices. In this case, the layer 525 can be referred to as a common layer. By providing one or more common layers to the plurality of light-emitting devices in this way, the manufacturing process can be simplified, and therefore the manufacturing cost can be reduced.

[0356] The light-emitting unit 512R_2 includes a layer 522, a light-emitting layer 523R, a layer 524, and the like. Although the example in which the layer 525 is provided as a common layer is shown in Fig. 15C, the layer 525 may be provided for each light-emitting device. In other words, the layer 525 may be included in the light-emitting unit 512R_2.

[0357] The layer 521 includes, for example, a layer containing a substance with a high hole-injection property (hole-injection layer). The layer 522 includes, for example, a layer containing a substance with a high hole-transport property (hole-transport layer). The layer 524 includes, for example, a layer containing a substance with a high electron-transport property (electron-transport layer). The layer 525 includes, for example, a layer containing a substance with a high electron-injection property (electron-injection layer).

[0358] Alternatively, a structure in which the layer 521 has an electron-injecting layer, the layer 522 has an electron-transporting layer, the layer 524 has a hole-transporting layer, and the layer 525 has a hole-injecting layer may be used.

[0359] The layer 522, the light-emitting layer 523R, and the layer 524 may have the same configuration (material, film thickness, etc.) between the light-emitting unit 512R_1 and the light-emitting unit 512R_2, or may have different configurations.

[0360] 15A and the like, the layer 521 and the layer 522 are separately illustrated, but this is not limiting. For example, when the layer 521 has a function of both a hole injection layer and a hole transport layer, or when the layer 521 has a function of both an electron injection layer and an electron transport layer, the layer 522 may be omitted.

[0361] The charge generation layer 531 has a function of injecting electrons into one of the light-emitting unit 512R_1 and the light-emitting unit 512R_2 and injecting holes into the other when a voltage is applied between the electrode 501 and the electrode 502. The charge generation layer 531 has at least a charge generation region.

[0362] The light-emitting layer 523R of the light-emitting device 550R contains a light-emitting material that emits red light, the light-emitting layer 523G of the light-emitting device 550G contains a light-emitting material that emits green light, and the light-emitting layer 523B of the light-emitting device 550B contains a light-emitting material that emits blue light. The light-emitting devices 550G and 550B have a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with the light-emitting layer 523G and the light-emitting layer 523B, respectively, and are otherwise similar in configuration to the light-emitting device 550R.

[0363] The layers 521, 522, 524, and 525 may have the same configuration (material, film thickness, etc.) for each color light-emitting device, or may have different configurations.

[0364] 15A and 15B, the light-emitting unit 512R_1, the light-emitting unit 512G_1, and the light-emitting unit 512B_1 can be formed as island layers. That is, the layer 113 shown in FIG. 15A and 15B corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B and the like.

[0365] 15C , the light-emitting unit 512R_1, the charge generation layer 531, and the light-emitting unit 512R_2 can be formed as island layers. The light-emitting unit 512G_1, the charge generation layer 531, and the light-emitting unit 512G_2 can be formed as island layers. The light-emitting unit 512B_1, the charge generation layer 531, and the light-emitting unit 512B_2 can be formed as island layers. In other words, the layer 113 shown in FIG. 15C corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B, etc.

[0366] In Figures 15B and 15C, layer 525 corresponds to fifth layer 114 shown in Figure 1B.

[0367] 15C , the light-emitting layer 523R of the light-emitting unit 512R_1 contains a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 contains a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 contains a fluorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 contains a fluorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 contains a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 contains a fluorescent material.

[0368] Alternatively, in the display device 500 shown in FIG. 15C, the light-emitting layer 523R of the light-emitting unit 512R_1 can have a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 can have a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 can have a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 can have a phosphorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 can have a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 can have a fluorescent material.

[0369] Note that the display device of one embodiment of the present invention may have a structure in which all light-emitting layers are formed using a fluorescent material or a structure in which all light-emitting layers are formed using a phosphorescent material.

[0370] 15C , the light-emitting layer 523R of the light-emitting unit 512R_1 may be made of a phosphorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 may be made of a fluorescent material, or the light-emitting layer 523R of the light-emitting unit 512R_1 may be made of a fluorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 may be made of a phosphorescent material, that is, the light-emitting layers of the first and second stages may be made of different materials. Note that while the light-emitting units 512R_1 and 512R_2 have been described above, similar configurations can also be applied to the light-emitting units 512G_1 and 512G_2, and the light-emitting units 512B_1 and 512B_2.

[0371] The display device 500 shown in Figures 16 to 18 has a light-emitting device 550R that emits red light, a light-emitting device 550G that emits green light, a light-emitting device 550B that emits blue light, and a light-emitting device 550W that emits white light.

[0372] The display device shown in Figures 16A and 16B is an example in which a light-emitting device 550W that emits white light is provided in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 15B. The display device shown in Figure 17A is an example in which a light-emitting device 550W that emits white light is provided in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 15C.

[0373] The light-emitting device 550W shown in Figures 16A and 17A has a configuration in which two light-emitting units (light-emitting unit 512Q_1 and light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501 and electrode 502) with a charge generation layer 531 interposed therebetween.

[0374] The light-emitting device 550W shown in Figure 16B has a configuration in which three light-emitting units (light-emitting unit 512Q_1, light-emitting unit 512Q_2, and light-emitting unit 512Q_3) are stacked between a pair of electrodes (electrode 501 and electrode 502) with a charge generation layer 531 interposed between them.

[0375] The light-emitting unit 512Q_1 includes a layer 521, a layer 522, a light-emitting layer 523Q_1, a layer 524, etc. The light-emitting unit 512Q_2 includes a layer 522, a light-emitting layer 523Q_2, a layer 524, etc. The light-emitting unit 512Q_3 includes a layer 522, a light-emitting layer 523Q_3, a layer 524, etc.

[0376] In the light-emitting device 550W shown in FIGS. 16A and 17A, white light can be emitted from the light-emitting device 550W by selecting light-emitting layers 523Q_1 and 523Q_2 such that the light emitted from the light-emitting layers 523Q_1 and 523Q_2 has a complementary color relationship.

[0377] In the light-emitting device 550W shown in FIG. 16B, white light can be obtained from the light-emitting device 550W by selecting light-emitting layers 523Q_1, 523Q_2, and 523Q_3 such that the light emitted from these layers has a complementary color relationship.

[0378] The light-emitting device 550W has a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with a light-emitting layer 523Q_1 or the like, and the other configurations are the same as those of the light-emitting device 550R.

[0379] The display device 500 shown in FIG. 17B is an example in which a light-emitting device 550R emitting red light, a light-emitting device 550G emitting green light, a light-emitting device 550B emitting blue light, and a light-emitting device 550W emitting white light all have a three-tiered tandem structure in which three light-emitting units are stacked. In FIG. 17B , the light-emitting device 550R has a light-emitting unit 512R_3 stacked on top of a light-emitting unit 512R_2 with a charge generation layer 531 interposed therebetween. The light-emitting unit 512R_3 includes a layer 522, a light-emitting layer 523R, a layer 524, and the like. The light-emitting unit 512R_3 can have a similar configuration to the light-emitting unit 512R_2. The same applies to the light-emitting unit 512G_3 included in the light-emitting device 550G, the light-emitting unit 512B_3 included in the light-emitting device 550B, and the light-emitting unit 512Q_3 included in the light-emitting device 550W.

[0380] FIG. 18A shows an example in which a light emitting device 550W that emits white light is provided in addition to the light emitting devices 550R, 550G, and 550B shown in FIG. 15A.

[0381] 18A has a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531. The light-emitting device 550W has n light-emitting units, light-emitting unit 512Q_1 to light-emitting unit 512Q_n, and the light from these light-emitting units has a complementary color relationship, so that the light can emit white light.

[0382] 18B , a light-emitting device 550R emitting red light, a light-emitting device 550G emitting green light, a light-emitting device 550B emitting blue light, and a light-emitting device 550W emitting white light all have a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked. The light-emitting device 550R has n light-emitting units, light-emitting unit 512R_1 to light-emitting unit 512R_n, each having a light-emitting layer that emits red light. The light-emitting device 550G has n light-emitting units, light-emitting unit 512G_1 to light-emitting unit 512G_n, each having a light-emitting layer that emits green light. The light-emitting device 550B has n light-emitting units, light-emitting unit 512B_1 to light-emitting unit 512B_n, each having a light-emitting layer that emits blue light.

[0383] In this way, by increasing the number of stacked light-emitting units, the luminance obtained from the light-emitting device with the same amount of current can be increased in proportion to the number of stacked light-emitting units.Furthermore, by increasing the number of stacked light-emitting units, the current required to obtain the same luminance can be reduced, and therefore the power consumption of the light-emitting device can be reduced in proportion to the number of stacked light-emitting units.

[0384] This embodiment mode can be combined with other embodiment modes as appropriate.

[0385] Embodiment 3 In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0386] 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.

[0387] [Display Device 100A] FIG. 19 shows a perspective view of the display device 100A, and FIG. 20A shows a cross-sectional view of the display device 100A.

[0388] The display device 100A has a configuration in which a substrate 152 and a substrate 151 are bonded together. In Fig. 19, the substrate 152 is clearly indicated by a dashed line.

[0389] The display device 100A includes a display portion 162, a circuit 164, wiring 165, and the like. Fig. 19 shows an example in which an IC 173 and an FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Fig. 19 can also be considered as a display module including the display device 100A, an IC (integrated circuit), and an FPC.

[0390] The circuit 164 can be, for example, a scanning line driver circuit.

[0391] The wiring 165 has a function of supplying signals and power to the display portion 162 and the circuit 164. The signals and power are input to the wiring 165 from the outside via the FPC 172 or input to the wiring 165 from the IC 173.

[0392] 19 shows an example in which an IC 173 is provided on a substrate 151 by a chip-on-glass (COG) method or a chip-on-film (COF) method. The IC 173 may be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 100A and the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by a COF method or the like.

[0393] FIG. 20A shows an example of a cross section of the display device 100A, in which a part of a region including the FPC 172, a part of the circuit 164, a part of the display portion 162, and a part of a region including an end portion are cut away.

[0394] The display device 100A shown in Figure 20A has, between a substrate 151 and a substrate 152, a transistor 201, a transistor 205, a light-emitting device 130a that emits red light, a light-emitting device 130b that emits green light, and a light-emitting device 130c that emits blue light.

[0395] Here, when a pixel of a display device has three types of subpixels having light-emitting devices that emit light of different colors, the three subpixels include subpixels of three colors of R, G, and B, or subpixels of three colors of yellow (Y), cyan (C), and magenta (M), etc. When a pixel of a display device has four subpixels, the four subpixels include subpixels of four colors of R, G, B, and white (W), or subpixels of four colors of R, G, B, and Y, etc.

[0396] The light-emitting devices 130a, 130b, and 130c each have a similar structure to the stacked structure shown in FIG. 1B except that an optical adjustment layer is provided between the pixel electrode and the EL layer. The light-emitting device 130a has an optical adjustment layer 126a, the light-emitting device 130b has an optical adjustment layer 126b, and the light-emitting device 130c has an optical adjustment layer 126c. For details of the light-emitting devices, refer to Embodiment 1. The side surfaces of the pixel electrodes 111a, 111b, and 111c, the optical adjustment layers 126a, 126b, and 126c, the first layer 113a, the second layer 113b, and the third layer 113c are covered with sidewalls 125a and 125b, respectively. A fifth layer 114 is provided on the first layer 113a, the second layer 113b, the third layer 113c, and the sidewalls 125a and 125b, and a common electrode 115 is provided on the fifth layer 114. In addition, a protective layer 131 is provided on each of the light-emitting devices 130a, 130b, and 130c. A protective layer 132 is provided on the protective layer 131.

[0397] 20A shows an example in which optical adjustment layer 126a is thicker than optical adjustment layer 126b, which is thicker than optical adjustment layer 126c. It is preferable to set the thickness of optical adjustment layer 126a so as to enhance red light, optical adjustment layer 126b so as to enhance green light, and optical adjustment layer 126c so as to enhance blue light. This allows for a microcavity structure to be realized, improving the color purity of the light emitted by each light-emitting device.

[0398] The optical adjustment layer is preferably formed using a conductive material that is transparent to visible light, among conductive materials that can be used as electrodes of a light-emitting device.

[0399] The protective layer 132 and the substrate 152 are bonded via an adhesive layer 142. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting device. In FIG. 20A , the space between the substrates 152 and 151 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Alternatively, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0400] The pixel electrodes 111 a , 111 b , and 111 c are connected to a conductive layer 222 b of the transistor 205 through openings provided in the insulating layer 214 .

[0401] The pixel electrodes include a material that reflects visible light, and the common electrode 115 (which may also be called a counter electrode) includes a material that transmits visible light.

[0402] The display device 100A is a top-emission type. Light emitted from the light-emitting device is emitted toward the substrate 152. The substrate 152 is preferably made of a material that is highly transparent to visible light.

[0403] The stacked structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 including the transistor in Embodiment 1.

[0404] The transistor 201 and the transistor 205 are both formed over a substrate 151. These transistors can be manufactured using the same material and through the same process.

[0405] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 151 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for 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.

[0406] 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.

[0407] 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.

[0408] 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.

[0409] An organic insulating film is suitable for the insulating layer 214, which functions as a planarization 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, phenolic resin, and precursors of these resins. The insulating layer 214 may also have a laminated structure of an organic insulating film and an inorganic insulating film. The outermost layer of the insulating layer 214 preferably functions as an etching protection film. This can prevent recesses from being formed in the insulating layer 214 during processing of the sidewalls 125a, 125b, etc. Alternatively, recesses may be formed in the insulating layer 214 during processing of the sidewalls 125a, 125b, etc.

[0410] 20A , an opening is formed in insulating layer 214. This makes it possible to prevent impurities from entering display unit 162 from the outside through insulating layer 214, even when an organic insulating film is used for insulating layer 214. This makes it possible to improve the reliability of display device 100A.

[0411] 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.

[0412] 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.

[0413] 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.

[0414] 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.

[0415] 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 in which a channel formation region is formed using metal oxide (hereinafter referred to as an OS transistor). 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).

[0416] 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.

[0417] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) for the semiconductor layer. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc.

[0418] 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.

[0419] 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 In is taken as 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when In is taken as 5, Ga is more than 0.1 and 2 or less and Zn is 5 to 7. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when In is taken as 1, Ga is more than 0.1 and 2 or less and Zn is more than 0.1 and 2 or less.

[0420] The transistors included in the circuit 164 may have the same structure as or different from the transistors included in the display portion 162. The transistors included in the circuit 164 may all have the same structure or may have two or more types. Similarly, the transistors included in the display portion 162 may all have the same structure or may have two or more types.

[0421] 20B and 20C show other examples of the configuration of the transistor.

[0422] The transistor 209 and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer 231 including a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel formation region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0423] 20B shows an example in which the insulating layer 225 covers the top surface and side surfaces of the semiconductor layer 231. The conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0424] 20C , the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the insulating layer 225 is processed using the conductive layer 223 as a mask, thereby manufacturing the structure shown in FIG. 20C . In FIG. 20C , the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings in the insulating layer 215.

[0425] A connection portion 204 is provided in a region of the substrate 151 where the substrate 152 does not overlap. In the connection portion 204, the wiring 165 is electrically connected to the FPC 172 via a conductive layer 166 and a connection layer 242. The conductive layer 166 has an example of a laminated structure of a conductive film obtained by processing the same conductive film as the pixel electrode and a conductive film obtained by processing the same conductive film as the optical adjustment layer 126c. The conductive layer 166 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 172 to be electrically connected via the connection layer 242.

[0426] It is preferable to provide a light-shielding layer 117 on the surface of substrate 152 facing substrate 151. In addition, various optical members can be arranged on the outside of substrate 152. 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 the occurrence of scratches during use, an impact absorbing layer, etc. may be arranged on the outside of substrate 152.

[0427] By providing the protective layers 131 and 132 that cover the light-emitting device, impurities such as water can be prevented from entering the light-emitting device, and the reliability of the light-emitting device can be improved.

[0428] 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 or the protective layer 132 contact each other through the opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating films contact each other. This makes it possible to prevent impurities from entering the display unit 162 from the outside via the organic insulating film. This can therefore improve the reliability of the display device 100A.

[0429] The substrate 151 and the substrate 152 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 device is extracted. Using a flexible material for the substrate 151 and the substrate 152 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used for the substrate 151 or the substrate 152.

[0430] Substrates 151 and 152 may each 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. One or both of substrates 151 and 152 may be made of glass having a thickness sufficient to provide flexibility.

[0431] 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).

[0432] 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.

[0433] 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.

[0434] 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.

[0435] The adhesive layer 142 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.

[0436] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0437] 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.

[0438] 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 display devices, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) in light-emitting devices.

[0439] 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.

[0440] 21 is different from the display device 100A mainly in that it is a bottom emission type. Note that a description of the same parts as those of the display device 100A will be omitted.

[0441] Light emitted from the light-emitting device is emitted toward the substrate 151. A material that is highly transparent to visible light is preferably used for the substrate 151. On the other hand, the light-transmitting property of the material used for the substrate 152 does not matter.

[0442] A light-shielding layer 117 is preferably formed between the substrate 151 and the transistor 201 and between the substrate 151 and the transistor 205. Fig. 21 shows an example in which the light-shielding layer 117 is provided over the substrate 151, the insulating layer 153 is provided over the light-shielding layer 117, and the transistors 201, 205, and the like are provided over the insulating layer 153.

[0443] This embodiment mode can be combined with other embodiment modes as appropriate.

[0444] Embodiment 4 In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0445] The display device of the present embodiment can be a high-definition display device, and therefore can be used as a display unit of a wearable device that can be worn on the head, such as a wristwatch-type or bracelet-type information terminal (wearable device), a head-mounted display or other VR device, or a glasses-type AR device.

[0446] 22A shows a perspective view of a display module 280. The display module 280 includes a display device 100C and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100C, and may be a display device 100D or a display device 100E, which will be described later.

[0447] 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.

[0448] 22B 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.

[0449] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 22B. The pixel 284a has light-emitting devices 130a, 130b, and 130c that emit light of different colors. The plurality of light-emitting devices can be arranged in a stripe array as shown in Fig. 22B. Various light-emitting device arrangement methods, such as a delta array or a pentile array, can also be applied.

[0450] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0451] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. 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 element for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0452] 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.

[0453] 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 may be mounted on the FPC 290.

[0454] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are provided overlapping 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 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a be 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.

[0455] 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.

[0456] [Display Device 100C] A display device 100C shown in FIG. 23 includes a substrate 301, light-emitting devices 130a, 130b, and 130c, a capacitor 240, and a transistor 310.

[0457] 22A and 22B. The stacked structure from the substrate 301 to the insulating layer 255b corresponds to the layer 101 including the transistor in Embodiment 1.

[0458] 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 one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0459] An element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0460] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0461] 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.

[0462] 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.

[0463] An insulating layer 255a is provided to cover the capacitor 240, an insulating layer 255b is provided on the insulating layer 255a, and light-emitting devices 130a, 130b, 130c, etc. are provided on the insulating layer 255b. In this embodiment, an example is shown in which the light-emitting devices 130a, 130b, and 130c have a stacked structure similar to the stacked structure shown in FIG. 1B . Side surfaces of the pixel electrodes 111a, 111b, and 111c, the first layer 113a, the second layer 113b, and the third layer 113c are covered with sidewalls 125a and 125b, respectively. A fifth layer 114 is provided on the first layer 113a, the second layer 113b, the third layer 113c, and the sidewalls 125a and 125b, and a common electrode 115 is provided on the fifth layer 114. Furthermore, a protective layer 131 is provided on the light-emitting devices 130a, 130b, and 130c. A protective layer 132 is provided on the protective layer 131, and a substrate 120 is bonded to the protective layer 132 via a resin layer 122. For details of the components from the light-emitting devices to the substrate 120, refer to Embodiment 1. The substrate 120 corresponds to the substrate 292 in FIG. 22A .

[0464] The insulating layers 255a and 255b can be formed using various inorganic insulating films such as an insulating oxide film, an insulating nitride film, an oxynitride insulating film, and an insulating nitride oxide film. The insulating layer 255a is preferably formed using an oxide insulating film or an oxynitride insulating film such as a silicon oxide film, a silicon oxynitride film, or an aluminum oxide film. The insulating layer 255b is preferably formed using a nitride insulating film or a nitride oxide insulating film such as a silicon nitride film or a silicon nitride oxide film. More specifically, the insulating layer 255a is preferably formed using a silicon oxide film, and the insulating layer 255b is preferably formed using a silicon nitride film. The insulating layer 255b preferably functions as an etching protective film. Alternatively, the insulating layer 255a may be formed using a nitride insulating film or a nitride oxide insulating film, and the insulating layer 255b may be formed using an oxide insulating film or an oxynitride insulating film. Although this embodiment shows an example in which a recess is provided in the insulating layer 255b, the insulating layer 255b does not necessarily have a recess.

[0465] The pixel electrode of the light-emitting device is electrically connected to one of the source and drain of the transistor 310 via a plug 256 embedded in the insulating layers 255a and 255b, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the top surface of the insulating layer 255b and the height of the top surface of the plug 256 are the same or approximately the same. Various conductive materials can be used for the plug.

[0466] 24 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.

[0467] The transistor 320 is a transistor (OS transistor) in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0468] 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 .

[0469] 22A and 22B . The stacked structure from the substrate 331 to the insulating layer 255b corresponds to the layer 101 including the transistor in Embodiment 1. The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0470] 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.

[0471] 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.

[0472] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor properties. Materials that can be suitably used for the semiconductor layer 321 will be described in detail later.

[0473] 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.

[0474] 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.

[0475] 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.

[0476] The top surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are the same or approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0477] 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.

[0478] 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, and the insulating layer 264. 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.

[0479] 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.

[0480] 25 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 devices 100C and 100D may be omitted.

[0481] 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.

[0482] 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.

[0483] By using this configuration, not only pixel circuits but also driving circuits etc. can be formed directly below the light-emitting device, making it possible to make the display device smaller than when driving circuits are provided around the periphery of the display area.

[0484] This embodiment mode can be combined with other embodiment modes as appropriate.

[0485] Embodiment 5 In this embodiment, a structural example of a transistor that can be applied to a display device of one embodiment of the present invention will be described. In particular, the case where a transistor containing silicon as a semiconductor in which a channel is formed will be described.

[0486] One embodiment of the present invention is a display device including a light-emitting device and a pixel circuit. The display device can achieve a full-color display device by including, for example, three types of light-emitting devices that emit red (R), green (G), and blue (B) light, respectively.

[0487] It is preferable that all transistors included in a pixel circuit that drives a light-emitting device be transistors having silicon in a semiconductor layer where a channel is formed. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, it is preferable to use a transistor having low temperature polysilicon (LTPS) in the semiconductor layer (hereinafter also referred to as an LTPS transistor). LTPS transistors have high field-effect mobility and good frequency characteristics.

[0488] By using silicon transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0489] At least one of the transistors included in the pixel circuit preferably includes a transistor (hereinafter also referred to as an OS transistor) having a metal oxide (hereinafter also referred to as an oxide semiconductor) as a semiconductor in which a channel is formed. The OS transistor has significantly higher field-effect mobility than an amorphous silicon transistor. Furthermore, the OS transistor has a significantly smaller source-drain leakage current in an off state (hereinafter also referred to as an off-state current), and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0490] A display device with low power consumption and high driving capability can be realized by using LTPS transistors for some of the transistors included in a pixel circuit and OS transistors for the other. As a more preferred example, it is preferable to use OS transistors as transistors that function as switches for controlling conduction / non-conduction between wirings and LTPS transistors as transistors that control current.

[0491] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling a current flowing through a light-emitting device and can be called a driving transistor. One of the source and drain of the driving transistor is electrically connected to a pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor as the driving transistor. This allows the current flowing through the light-emitting device in the pixel circuit to be increased.

[0492] On the other hand, another transistor provided in the pixel circuit functions as a switch for controlling pixel selection / non-selection and can also be called a selection transistor. The gate of the selection transistor is electrically connected to a gate line, and one of the source and drain is electrically connected to a source line (signal line). It is preferable to use an OS transistor as the selection transistor. This allows the gradation of a pixel to be maintained even when the frame frequency is significantly reduced (for example, 1 fps or less), and therefore power consumption can be reduced by stopping the driver when displaying a still image.

[0493] A more specific configuration example will be described below with reference to the drawings.

[0494] 26A shows a block diagram of the display device 10. The display device 10 includes a display unit 11, a drive circuit unit 12, a drive circuit unit 13, and the like.

[0495] The display unit 11 has a plurality of pixels 30 arranged in a matrix. Each pixel 30 has sub-pixels 21R, 21G, and 21B. Each of the sub-pixels 21R, 21G, and 21B has a light-emitting device that functions as a display device.

[0496] The pixel 30 is electrically connected to a wiring GL, a wiring SLR, a wiring SLG, and a wiring SLB. The wirings SLR, SLG, and SLB are each electrically connected to a driver circuit unit 12. The wiring GL is electrically connected to a driver circuit unit 13. The driver circuit unit 12 functions as a source line driver circuit (also referred to as a source driver), and the driver circuit unit 13 functions as a gate line driver circuit (also referred to as a gate driver). The wiring GL functions as a gate line, and the wirings SLR, SLG, and SLB function as source lines.

[0497] Sub-pixel 21R has a light-emitting device that emits red light. Sub-pixel 21G has a light-emitting device that emits green light. Sub-pixel 21B has a light-emitting device that emits blue light. This allows the display device 10 to display full color. Note that pixel 30 may also have sub-pixels that have light-emitting devices that emit light of other colors. For example, in addition to the above three sub-pixels, pixel 30 may also have a sub-pixel that has a light-emitting device that emits white light, or a sub-pixel that has a light-emitting device that emits yellow light, etc.

[0498] The wiring GL is electrically connected to the sub-pixels 21R, 21G, and 21B arranged in the row direction (extension direction of the wiring GL). The wiring SLR, wiring SLG, and wiring SLB are electrically connected to the sub-pixels 21R, 21G, and 21B (not shown) arranged in the column direction (extension direction of the wiring SLR, etc.), respectively.

[0499] [Configuration Example of Pixel Circuit] Figure 26B shows an example of a circuit diagram of a pixel 21 that can be applied to the subpixels 21R, 21G, and 21B. The pixel 21 includes a transistor M1, a transistor M2, a transistor M3, a capacitor C1, and a light-emitting device EL. A wiring GL and a wiring SL are electrically connected to the pixel 21. The wiring SL corresponds to any one of the wirings SLR, SLG, and SLB shown in Figure 26A.

[0500] The transistor M1 has a gate electrically connected to a wiring GL, one of a source and a drain electrically connected to a wiring SL, and the other electrically connected to one electrode of a capacitor C1 and the gate of the transistor M2. The transistor M2 has one of a source and a drain electrically connected to a wiring AL, and the other of a source and a drain electrically connected to one electrode of a light-emitting device EL, the other electrode of the capacitor C1, and one of a source and a drain of the transistor M3. The transistor M3 has a gate electrically connected to a wiring GL, and the other of a source and a drain electrically connected to a wiring RL. The light-emitting device EL has the other electrode electrically connected to a wiring CL.

[0501] A data potential is applied to the wiring SL. A selection signal is applied to the wiring GL. The selection signal includes a potential that turns on a transistor and a potential that turns off a transistor.

[0502] A reset potential is applied to the wiring RL. An anode potential is applied to the wiring AL. A cathode potential is applied to the wiring CL. In the pixel 21, the anode potential is higher than the cathode potential. The reset potential applied to the wiring RL can be a potential such that the potential difference between the reset potential and the cathode potential is smaller than the threshold voltage of the light-emitting device EL. The reset potential can be a potential higher than the cathode potential, the same as the cathode potential, or a potential lower than the cathode potential.

[0503] The transistors M1 and M3 function as switches. The transistor M2 functions as a transistor for controlling the current flowing through the light-emitting device EL. For example, it can be said that the transistor M1 functions as a selection transistor and the transistor M2 functions as a drive transistor.

[0504] Here, it is preferable that all of the transistors M1 to M3 be LTPS transistors. Alternatively, it is preferable that the transistors M1 and M3 be OS transistors and the transistor M2 be an LTPS transistor.

[0505] Alternatively, all of the transistors M1 to M3 may be OS transistors. In this case, one or more of the transistors included in the driver circuit portion 12 and the transistors included in the driver circuit portion 13 may be LTPS transistors, and the remaining transistors may be OS transistors. For example, OS transistors may be used as transistors provided in the display portion 11, and LTPS transistors may be used as transistors provided in the driver circuit portion 12 and the driver circuit portion 13.

[0506] A transistor using an oxide semiconductor, which has a wider band gap and a lower carrier concentration than silicon, can achieve an extremely small off-state current. Therefore, the small off-state current allows charge stored in a capacitor connected in series with the transistor to be held for a long period of time. Therefore, it is preferable to use transistors including oxide semiconductors for the transistors M1 and M3 connected in series with the capacitor C1. Using transistors including oxide semiconductors as the transistors M1 and M3 can prevent charge stored in the capacitor C1 from leaking through the transistor M1 or M3. Furthermore, because charge stored in the capacitor C1 can be held for a long period of time, a still image can be displayed for a long period of time without rewriting data in the pixel 21.

[0507] Note that although the transistors are shown as n-channel transistors in FIG. 26B, p-channel transistors can also be used.

[0508] Moreover, it is preferable that the transistors included in the pixel 21 are formed side by side on the same substrate.

[0509] As the transistor included in the pixel 21, a transistor having a pair of gates overlapping with each other with a semiconductor layer interposed therebetween can be used.

[0510] In a transistor having a pair of gates, when the pair of gates are electrically connected to each other and supplied with the same potential, the on-state current of the transistor is increased and the saturation characteristics are improved. A potential for controlling the threshold voltage of the transistor may be supplied to one of the pair of gates. Supplying a constant potential to one of the pair of gates can improve the stability of the electrical characteristics of the transistor. For example, one gate of the transistor may be electrically connected to a wiring to which a constant potential is supplied, or to its own source or drain.

[0511] 26C is an example of a pixel 21 in which the transistors M1 and M3 each have a pair of gates. The pair of gates of the transistors M1 and M3 are electrically connected. With this configuration, the period for writing data to the pixel 21 can be shortened.

[0512] 26D is an example in which a transistor having a pair of gates is used for the transistor M2 in addition to the transistors M1 and M3. The pair of gates of the transistor M2 are electrically connected. By using such a transistor for the transistor M2, the saturation characteristics are improved, which makes it easier to control the light emission luminance of the light-emitting device EL, thereby improving the display quality.

[0513] [Example of Transistor Structure] Hereinafter, an example of a cross-sectional structure of a transistor that can be applied to the display device will be described.

[0514] Configuration Example 1 FIG. 27A is a cross-sectional view including a transistor 410. FIG.

[0515] The transistor 410 is provided on the substrate 401 and has a semiconductor layer made of polycrystalline silicon. For example, the transistor 410 corresponds to the transistor M2 of the pixel 21. That is, Fig. 27A illustrates an example in which one of the source and the drain of the transistor 410 is electrically connected to the conductive layer 431 of the light-emitting device.

[0516] The transistor 410 includes a semiconductor layer 411, an insulating layer 412, a conductive layer 413, and the like. The semiconductor layer 411 includes a channel formation region 411i and a low-resistance region 411n. The semiconductor layer 411 includes silicon. The semiconductor layer 411 preferably includes polycrystalline silicon. A part of the insulating layer 412 functions as a gate insulating layer. A part of the conductive layer 413 functions as a gate electrode.

[0517] Note that the semiconductor layer 411 can also include a metal oxide (also referred to as an oxide semiconductor) that exhibits semiconductor characteristics. In this case, the transistor 410 can be called an OS transistor.

[0518] The low-resistance region 411n is a region containing an impurity element. For example, when the transistor 410 is an n-channel transistor, phosphorus, arsenic, or the like may be added to the low-resistance region 411n. On the other hand, when the transistor 410 is a p-channel transistor, boron, aluminum, or the like may be added to the low-resistance region 411n. Furthermore, in order to control the threshold voltage of the transistor 410, the above-mentioned impurities may be added to the channel formation region 411i.

[0519] An insulating layer 421 is provided over a substrate 401. A semiconductor layer 411 is provided over the insulating layer 421. An insulating layer 412 is provided to cover the semiconductor layer 411 and the insulating layer 421. A conductive layer 413 is provided over the insulating layer 412 so as to overlap with the semiconductor layer 411.

[0520] An insulating layer 422 is provided to cover the conductive layer 413 and the insulating layer 412. A conductive layer 414a and a conductive layer 414b are provided over the insulating layer 422. The conductive layer 414a and the conductive layer 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 422 and the insulating layer 412. A part of the conductive layer 414a functions as one of the source electrode and the drain electrode, and a part of the conductive layer 414b functions as the other of the source electrode and the drain electrode. An insulating layer 423 is provided to cover the conductive layer 414a, the conductive layer 414b, and the insulating layer 422.

[0521] A conductive layer 431 functioning as a pixel electrode is provided over the insulating layer 423. The conductive layer 431 is provided over the insulating layer 423 and is electrically connected to the conductive layer 414b in an opening provided in the insulating layer 423. Although not shown here, an EL layer and a common electrode can be stacked over the conductive layer 431.

[0522] 27B shows a transistor 410a having a pair of gate electrodes, which is different from the transistor 410a shown in FIG. 27A in that a conductive layer 415 and an insulating layer 416 are included.

[0523] The conductive layer 415 is provided over the insulating layer 421. An insulating layer 416 is provided to cover the conductive layer 415 and the insulating layer 421. The semiconductor layer 411 is provided so that at least a channel formation region 411i overlaps with the conductive layer 415 with the insulating layer 416 interposed therebetween.

[0524] 27B , part of the conductive layer 413 functions as a first gate electrode, part of the conductive layer 415 functions as a second gate electrode, part of the insulating layer 412 functions as a first gate insulating layer, and part of the insulating layer 416 functions as a second gate insulating layer.

[0525] Here, when the first gate electrode and the second gate electrode are electrically connected, the conductive layer 413 and the conductive layer 415 may be electrically connected through openings provided in the insulating layers 412 and 416 in a region not shown. When the second gate electrode and the source or drain are electrically connected, the conductive layer 414a or the conductive layer 414b may be electrically connected to the conductive layer 415 through openings provided in the insulating layers 422, 412, and 416 in a region not shown.

[0526] 27A or 27B can be applied to all of the transistors constituting the pixel 21. In this case, the transistor 410a may be used for all of the transistors constituting the pixel 21, the transistor 410 may be used for all of the transistors constituting the pixel 21, or the transistor 410 may be used for all of the transistors, or the transistor 410a and the transistor 410 may be used in combination.

[0527] [Structure Example 3] Hereinafter, a structure example including both a transistor in which silicon is used for a semiconductor layer and a transistor in which a metal oxide is used for a semiconductor layer will be described.

[0528] FIG. 27C shows a cross-sectional schematic diagram including transistor 410a and transistor 450.

[0529] The transistor 410a can be configured as in the above-described Structure Example 1. Note that although the example using the transistor 410a is shown here, a structure including the transistor 410 and the transistor 450 may be used, or a structure including all of the transistor 410, the transistor 410a, and the transistor 450 may be used.

[0530] The transistor 450 is a transistor in which a metal oxide is used for a semiconductor layer. The configuration shown in Fig. 27C is an example in which the transistor 450 corresponds to the transistor M1 of the pixel 21 and the transistor 410a corresponds to the transistor M2. That is, Fig. 27C shows an example in which one of the source and the drain of the transistor 410a is electrically connected to the conductive layer 431.

[0531] FIG. 27C shows an example in which the transistor 450 has a pair of gates.

[0532] The transistor 450 includes a conductive layer 455, an insulating layer 422, a semiconductor layer 451, an insulating layer 452, a conductive layer 453, and the like. Part of the conductive layer 453 functions as a first gate of the transistor 450, and part of the conductive layer 455 functions as a second gate of the transistor 450. In this case, part of the insulating layer 452 functions as a first gate insulating layer of the transistor 450, and part of the insulating layer 422 functions as a second gate insulating layer of the transistor 450.

[0533] The conductive layer 455 is provided over the insulating layer 412. The insulating layer 422 is provided to cover the conductive layer 455. The semiconductor layer 451 is provided over the insulating layer 422. The insulating layer 452 is provided to cover the semiconductor layer 451 and the insulating layer 422. The conductive layer 453 is provided over the insulating layer 452 and has a region overlapping with the semiconductor layer 451 and the conductive layer 455.

[0534] An insulating layer 426 is provided to cover the insulating layer 452 and the conductive layer 453. A conductive layer 454a and a conductive layer 454b are provided over the insulating layer 426. The conductive layer 454a and the conductive layer 454b are electrically connected to the semiconductor layer 451 through openings provided in the insulating layer 426 and the insulating layer 452. A part of the conductive layer 454a functions as one of the source electrode and the drain electrode, and a part of the conductive layer 454b functions as the other of the source electrode and the drain electrode. An insulating layer 423 is provided to cover the conductive layer 454a, the conductive layer 454b, and the insulating layer 426.

[0535] Here, the conductive layers 414a and 414b electrically connected to the transistor 410a are preferably formed by processing the same conductive film as the conductive layers 454a and 454b. Figure 27C shows a configuration in which the conductive layers 414a, 414b, 454a, and 454b are formed on the same surface (i.e., in contact with the top surface of the insulating layer 426) and contain the same metal element. In this case, the conductive layers 414a and 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 426, the insulating layer 452, the insulating layer 422, and the insulating layer 412. This is preferable because it simplifies the manufacturing process.

[0536] The conductive layer 413 functioning as the first gate electrode of the transistor 410a and the conductive layer 455 functioning as the second gate electrode of the transistor 450 are preferably formed by processing the same conductive film. In Figure 27C, the conductive layer 413 and the conductive layer 455 are formed on the same surface (i.e., in contact with the top surface of the insulating layer 412) and contain the same metal element. This is preferable because it simplifies the manufacturing process.

[0537] In Figure 27C, the insulating layer 452 functioning as the first gate insulating layer of the transistor 450 covers the end portion of the semiconductor layer 451. However, as in the transistor 450a shown in Figure 27D, the insulating layer 452 may be processed so that the top surface shape thereof matches or approximately matches the top surface shape of the conductive layer 453.

[0538] In this specification, the phrase "top surface shapes generally match" refers to the overlap of at least a portion of the contours between stacked layers. For example, this includes cases where the upper and lower layers are processed using the same mask pattern or a portion of the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or outside the lower layer. In these cases, the phrase "top surface shapes generally match" also applies.

[0539] Although the transistor 410a corresponds to the transistor M2 and is electrically connected to the pixel electrode in this example, the present invention is not limited to this. For example, the transistor 450 or the transistor 450a may correspond to the transistor M2. In this case, the transistor 410a corresponds to the transistor M1, the transistor M3, or another transistor.

[0540] This embodiment mode can be combined with other embodiment modes as appropriate.

[0541] Embodiment 6 In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0542] 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.

[0543] The metal oxide can be formed by a sputtering method, a chemical vapor deposition (CVD) method such as a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method.

[0544] <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.

[0545] 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.

[0546] 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.

[0547] 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.

[0548] <<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.

[0549] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0550] [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.

[0551] 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.

[0552] 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.

[0553] 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.

[0554] 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).

[0555] 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.

[0556] 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.

[0557] 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.

[0558] [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.

[0559] [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.

[0560] <<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.

[0561] [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.

[0562] 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.

[0563] 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 CAC-OS composition. The second region is a region where [Ga] is larger than [Ga] in the CAC-OS composition. 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.

[0564] 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.

[0565] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0566] 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.

[0567] 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.

[0568] 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.

[0569] 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).

[0570] 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.

[0571] 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.

[0572] 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.

[0573] 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.

[0574] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0575] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0576] 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.

[0577] 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.

[0578] 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.

[0579] 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.

[0580] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0581] 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.

[0582] 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, preferably １６ atoms / cm ３ Do the following:

[0583] 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:

[0584] 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 ２０atoms / 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.

[0585] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0586] This embodiment mode can be combined with other embodiment modes as appropriate.

[0587] Embodiment 7 In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0588] 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.

[0589] 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.

[0590] 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.

[0591] 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.

[0592] 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).

[0593] 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.

[0594] 28A, 28B, 29A, and 29B, 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.

[0595] The electronic device 700A shown in FIG. 28A and the electronic device 700B shown in FIG. 28B 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.

[0596] 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.

[0597] 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 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.

[0598] 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.

[0599] 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.

[0600] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or by wire.

[0601] 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.

[0602] 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.

[0603] 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.

[0604] The electronic device 800A shown in FIG. 29A and the electronic device 800B shown in FIG. 29B 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.

[0605] 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.

[0606] 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.

[0607] 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.

[0608] 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.

[0609] The mounting unit 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head. Note that, in Fig. 29A 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.

[0610] 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.

[0611] 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.

[0612] 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.

[0613] 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.

[0614] 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, an electronic device 700A shown in FIG. 28A has a function of transmitting information to the earphone 750 through the wireless communication function. Furthermore, for example, an electronic device 800A shown in FIG. 29A has a function of transmitting information to the earphone 750 through the wireless communication function.

[0615] The electronic device may also have an earphone unit. Electronic device 700B shown in Fig. 28B 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 wearing unit 723.

[0616] Similarly, electronic device 800B shown in Fig. 29B 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.

[0617] 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.

[0618] 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.

[0619] Furthermore, the electronic device of one embodiment of the present invention can transmit information to the earphone by wire or wirelessly.

[0620] The electronic device 6500 shown in FIG. 30A is a portable information terminal that can be used as a smartphone.

[0621] 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.

[0622] The display device of one embodiment of the present invention can be applied to the display portion 6502 .

[0623] FIG. 30B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0624] 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.

[0625] 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).

[0626] 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.

[0627] 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.

[0628] 31A 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.

[0629] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0630] 31A 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.

[0631] The television device 7100 is configured to include a receiver, a modem, and the like. Ordinary television broadcasts can be received using the receiver. 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.

[0632] 31B 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. A display portion 7000 is incorporated in the housing 7211.

[0633] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0634] 31C and 31D show an example of digital signage.

[0635] 31C 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.

[0636] 31D 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.

[0637] 31C and 31D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0638] 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.

[0639] 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.

[0640] 31C and 31D , 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.

[0641] 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.

[0642] The electronic device shown in Figures 32A to 32G 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.

[0643] 32A to 32G, the display device of one embodiment of the present invention can be applied to the display portion 9001.

[0644] The electronic devices shown in Figures 32A to 32G 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 a display unit, etc.

[0645] Details of the electronic device shown in Figures 32A to 32G will be described below.

[0646] FIG. 32A 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. 32A 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.

[0647] 32B 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.

[0648] 32C is a perspective view showing a tablet terminal 9103. The tablet terminal 9103 is capable of executing various applications such as mobile phone calls, e-mail, text browsing and creation, music playback, internet communication, and computer games, for example. The tablet terminal 9103 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front side of a housing 9000, operation keys 9005 as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0649] FIG. 32D 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.

[0650] 32E to 32G are perspective views showing a foldable mobile information terminal 9201. Also, FIG. 32E is a perspective view of the mobile information terminal 9201 in an unfolded state, FIG. 32G is a perspective view of the mobile information terminal 9201 in a folded state, and FIG. 32F is a perspective view of a state in the process of changing from one of FIGS. 32E and 32G to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent visibility of the display. 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.

[0651] This embodiment mode can be combined with other embodiment modes as appropriate.

[0652] AL: wiring, CL: wiring, GL: wiring, IRS: subpixel, PS: subpixel, RL: wiring, SL: wiring, SLB: wiring, SLG: wiring, SLR: wiring, 10: display device, 11: display unit, 12: drive circuit unit, 13: drive circuit unit, 21B: subpixel, 21G: subpixel, 21R: subpixel, 21: pixel, 30: pixel, 100A: display device, 100B: display device, 100C: display device, 100D: display device, 100E: display device, 100: display device, 101: layer, 110a: subpixel, 110b: subpixel, 110c: subpixel, 110d: subpixel, 110: pixel, 111 a: pixel electrode, 111b: pixel electrode, 111c: pixel electrode, 111d: pixel electrode, 111: conductive film, 113a: first layer, 113b: second layer, 113c: third layer, 113d: fourth layer, 113: layer, 114: fifth layer, 115: common electrode, 117: light-shielding layer, 118A: first sacrificial layer, 118a: first sacrificial layer, 118B: first sacrificial layer, 118b: first sacrificial layer, 118C: first sacrificial layer, 118c: first sacrificial layer, 119A: second sacrificial layer, 119a: second sacrificial layer, 119B: second sacrificial layer, 119b: second sacrificial layer, 119C: second sacrificial layer layer, 119c: second sacrificial layer, 120: substrate, 122: resin layer, 123: conductive layer, 124a: pixel, 124b: pixel, 125a: side wall, 125A: insulating film, 125b: side wall, 125B: insulating film, 125: side wall, 126a: optical adjustment layer, 126b: optical adjustment layer, 126c: optical adjustment layer, 130a: light emitting device, 130b: light emitting device, 130c: light emitting device, 130d: light emitting device, 131: protective layer, 132: protective layer, 134: gap, 140: connecting portion, 142: adhesive layer, 151: substrate, 152: substrate, 153: insulating layer, 162: display portion, 16 4: circuit, 165: wiring, 166: conductive layer, 172: FPC, 173: IC, 181A: first light-emitting unit, 181a: first light-emitting unit, 181B: first light-emitting unit, 181b: first light-emitting unit, 181C: first light-emitting unit, 181c: first light-emitting unit, 181d: first light-emitting unit, 182A: charge generation layer, 182a: charge generation layer, 182B: charge generation layer, 182b: charge generation layer, 182C: charge generation layer, 182c: charge generation layer, 182d: charge generation layer, 183A: second light-emitting unit, 183a: second light-emitting unit,183B: second light-emitting unit, 183b: second light-emitting unit, 183C: second light-emitting unit, 183c: second light-emitting unit, 183d: second light-emitting unit, 190a: resist mask, 190b: resist mask, 190c: resist mask, 201: transistor, 204: connection portion, 205: transistor, 209: transistor, 210: transistor, 211: insulating layer, 213: insulating layer, 214: insulating layer, 215: insulating layer, 218: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 225: insulating layer, 2 28: region, 231i: channel formation region, 231n: low resistance region, 231: semiconductor layer, 240: capacitor, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255a: insulating layer, 255b: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274a: conductive layer, 274b: conductive layer, 274: plug, 280: display module, 281: display section, 282: circuit section, 283a: pixel circuit, 283: pixel circuit section , 284a: pixel, 284: pixel portion, 285: terminal portion, 286: wiring portion, 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, 351: substrate, 352: finger, 353: layer, 355: functional layer, 357: layer, 359: substrate, 4 01: substrate, 410a: transistor, 410: transistor, 411i: channel formation region, 411n: low resistance region, 411: semiconductor layer, 412: insulating layer, 413: conductive layer, 414a: conductive layer, 414b: conductive layer, 415: conductive layer, 416: insulating layer, 421: insulating layer, 422: insulating layer, 423: insulating layer, 426: insulating layer, 431: conductive layer, 450a: transistor, 450: transistor, 451: semiconductor layer, 452: insulating layer, 453: conductive layer, 454a: conductive layer, 454b: conductive layer, 455: conductive layer, 500: display device, 501: electrode, 502: electrode,512B_1: light-emitting unit, 512B_2: light-emitting unit, 512B_3: light-emitting unit, 512B_n: light-emitting unit, 512G_1: light-emitting unit, 512G_2: light-emitting unit, 512G_3: light-emitting unit, 512G_n: light-emitting unit, 512Q_1: light-emitting unit, 512Q_2: light-emitting unit, 512Q_3: light-emitting unit, 512Q_n: light-emitting unit, 512R_1: light-emitting unit, 512R_2: light-emitting unit, 512R_3: light-emitting unit, 512R_n: light-emitting unit, 521: layer, 522: layer, 523B: light-emitting layer, 523G: Light-emitting layer, 523Q_1: light-emitting layer, 523Q_2: light-emitting layer, 523Q_3: light-emitting layer, 523R: light-emitting layer, 524: layer, 525: layer, 531: charge generation layer, 550B: light-emitting device, 550G: light-emitting device, 550R: light-emitting device, 550W: light-emitting device, 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, 6516: 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, 7400: digital signage, 7401: pillar, 7411: information terminal, 9000: housing, 9001: display unit, 9002: camera, 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, 9103: Tablet terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

1. Forming an insulating layer; forming a conductive film on the insulating layer; forming a first layer on the conductive film; forming a first sacrificial layer on the first layer; processing the first layer and the first sacrificial layer to expose a portion of the conductive film; forming a second layer on the first sacrificial layer and on the conductive film; forming a second sacrificial layer on the second layer; processing the second layer and the second sacrificial layer to expose a portion of the conductive film; forming a first pixel electrode overlapping the first sacrificial layer and a second pixel electrode overlapping the second sacrificial layer by processing the conductive film; forming a first insulating film covering at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first layer, a side surface of the second layer, a side surface and a top surface of the first sacrificial layer, and a side surface and a top surface of the second sacrificial layer; forming a second insulating film on the first insulating film; forming a first sidewall and a second sidewall on the first sidewall, the first sidewall covering at least a side surface of the first pixel electrode and a side surface of the first layer, by processing the first insulating film and the second insulating film; removing the first sacrificial layer and the second sacrificial layer; A method for manufacturing a display device, comprising forming a common electrode over the first layer and the second layer.

2. In claim 1, forming a first sacrificial film and a second sacrificial film on the first sacrificial film as the first sacrificial layer; forming a first resist mask on the second sacrificial film, and then processing the second sacrificial film using the first resist mask; removing the first resist mask; The first sacrificial film is processed using the processed second sacrificial film as a hard mask; A method for manufacturing a display device, comprising: processing the first layer by using the processed first sacrificial film as a hard mask.

3. In claim 1 or 2, A method for manufacturing a display device, comprising: processing the conductive film by using the first sacrificial layer and the second sacrificial layer as a hard mask.

4. In any one of claims 1 to 3, the first layer has a first light-emitting unit, a charge generating layer on the first light-emitting unit, and a second light-emitting unit on the charge generating layer; The first light-emitting unit and the second light-emitting unit have light-emitting layers that emit light of the same color.

5. In any one of claims 1 to 4, A protective layer is formed on the common electrode.

6. In any one of claims 1 to 5, forming a third layer on the first layer and on the second layer after removing the first sacrificial layer and the second sacrificial layer; The common electrode is formed over the third layer.

7. In any one of claims 1 to 6, The method for manufacturing a display device further comprises forming a recess in the insulating layer in the processing of the conductive film.

8. a first light emitting device, a second light emitting device, a first sidewall, and a second sidewall; the first light-emitting device comprises a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generating layer on the first light-emitting unit, a second light-emitting unit on the first charge generating layer, and a common electrode on the second light-emitting unit; the second light-emitting device comprises a second pixel electrode, a third light-emitting unit on the second pixel electrode, a second charge generating layer on the third light-emitting unit, a fourth light-emitting unit on the second charge generating layer, and the common electrode on the fourth light-emitting unit; the first light-emitting device and the second light-emitting device have a function of emitting light of different colors; the first sidewall covers at least a side surface of the first pixel electrode and a side surface of the first charge generating layer; the second sidewall overlaps at least a side surface of the first pixel electrode and a side surface of the first charge generating layer via the first sidewall; the first light emitting device and the second light emitting device are disposed on an insulating layer; The display device, wherein the insulating layer has a recess.

9. In claim 8, the first light-emitting unit and the second light-emitting unit each emit light of a first color; The third light-emitting unit and the fourth light-emitting unit each emit light of a second color.

10. a first light emitting device, a second light emitting device, a third light emitting device, a first sidewall, and a second sidewall; the first light-emitting device comprises a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generating layer on the first light-emitting unit, a second light-emitting unit on the first charge generating layer, and a common electrode on the second light-emitting unit; the second light-emitting device comprises a second pixel electrode, a third light-emitting unit on the second pixel electrode, a second charge generating layer on the third light-emitting unit, a fourth light-emitting unit on the second charge generating layer, and the common electrode on the fourth light-emitting unit; the third light-emitting device comprises a third pixel electrode, a fifth light-emitting unit on the third pixel electrode, a third charge generating layer on the fifth light-emitting unit, a sixth light-emitting unit on the third charge generating layer, and the common electrode on the sixth light-emitting unit; the first light-emitting device, the second light-emitting device, and the third light-emitting device each have a function of emitting light of a different color; the first sidewall covers at least a side surface of the first pixel electrode and a side surface of the first charge generating layer; the second sidewall overlaps at least a side surface of the first pixel electrode and a side surface of the first charge generating layer via the first sidewall; The display device further comprises an air gap between the first light emitting device and the second light emitting device.

11. In claim 10, the first light-emitting unit and the second light-emitting unit each emit light of a first color; the third light-emitting unit and the fourth light-emitting unit each emit light of a second color; The fifth light-emitting unit and the sixth light-emitting unit each emit light of a third color.

12. In claim 11, the first color is red; the second color is green; The display device, wherein the third color is blue.

13. In any one of claims 8 to 12, The display device further comprises a protective layer on the common electrode.