Method for manufacturing a display device

Abstract

Provided is a display device having high display quality. Provided is a display device having high reliability. Provided is a display device having low power consumption. Provided is a display device facilitating higher definition. Provided is a display device having both high display quality and high definition. Provided is a display device having high contrast. The present invention is a display device including an insulation layer, a first lower electrode, a first EL layer upon the first lower electrode, a second lower electrode, a second EL layer upon the second lower electrode, and an upper electrode upon the first EL layer, upon the second EL layer, and upon the insulation layer, wherein the first EL layer includes a first light-emitting layer, the second EL layer includes a second light-emitting layer, the first EL layer and the second EL layer are adjacent, the insulation layer includes a resin or a resin precursor, and the insulation layer includes a region interposed between a first end surface of the first EL layer and a second end surface of the second EL layer.

Description

display device

[0001] FIELD OF THE INVENTION One embodiment of the present invention relates to a display device and a manufacturing method of the display device.

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

[0003] In recent years, there has been a demand for higher definition display panels. Devices requiring high-definition display panels include, for example, smartphones, tablet terminals, and notebook computers. Furthermore, stationary display devices such as televisions and monitors are also required to have higher definitions in line with the trend toward higher resolutions. Furthermore, devices requiring the highest definition include, for example, devices for virtual reality (VR) or augmented reality (AR).

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

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

[0006] Patent Document 2 discloses a display device for VR that uses an organic EL device.

[0007] Patent Document 1: JP 2002-324673 A, International Publication No. 2018 / 087625

[0008] An object of one embodiment of the present invention is to provide a display device with high display quality.An object of one embodiment of the present invention is to provide a display device with high reliability.An object of one embodiment of the present invention is to provide a display device with low power consumption.An object of one embodiment of the present invention is to provide a display device that can easily be made high-definition.An object of one embodiment of the present invention is to provide a display device that has both high display quality and high definition.An object of one embodiment of the present invention is to provide a display device with high contrast.

[0009] An object of one embodiment of the present invention is to provide a display device having a novel structure or a manufacturing method of the display device.An object of one embodiment of the present invention is to provide a method for manufacturing the above-described display device with high yield.An object of one embodiment of the present invention is to alleviate at least one of the problems of the prior art.

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

[0011] One embodiment of the present invention is a display device including an insulating layer, a first lower electrode, a first EL layer on the first lower electrode, a second lower electrode, a second EL layer on the second lower electrode, and upper electrodes on the first EL layer, the second EL layer, and the insulating layer, in which the first EL layer has a first light-emitting layer, the second EL layer has a second light-emitting layer, the first EL layer and the second EL layer are adjacent to each other, the insulating layer includes a resin or a resin precursor, and the insulating layer has a region sandwiched between a first end face of the first EL layer and a second end face of the second EL layer.

[0012] In the above configuration, the resin preferably has one or more selected from an acrylic resin, a polyimide resin, an epoxy resin, a polyamide resin, a polyimideamide resin, a siloxane resin, a benzocyclobutene-based resin, and a phenol resin, and the precursor of the resin preferably is a precursor of a resin having one or more selected from an acrylic resin, a polyimide resin, an epoxy resin, a polyamide resin, a polyimideamide resin, a siloxane resin, a benzocyclobutene-based resin, and a phenol resin.

[0013] In the above structure, the insulating layer preferably contacts the first end face and the second end face.

[0014] In the above structure, it is preferable that the top surfaces of the first EL layer, the second EL layer, and the insulating layer are approximately aligned.

[0015] In the above structure, the top surface of the insulating layer preferably has a region lower in height than the top surfaces of the first EL layer and the second EL layer.

[0016] In the above structure, the upper surface of the insulating layer preferably has a recess.

[0017] In the above structure, the upper surface of the insulating layer preferably has a convex portion.

[0018] In the above structure, it is preferable that a common layer including an electron injection layer or a hole injection layer is provided, and the common layer is in contact with the top surface of the first EL layer, the top surface of the second EL layer, and the top surface of the insulating layer.

[0019] In the above structure, it is preferable that the common layer includes an electron injection layer, the first EL layer has a first electron transport layer sandwiched between the first light-emitting layer and the common layer, the second EL layer has a second electron transport layer sandwiched between the second light-emitting layer and the common layer, and the common layer is in contact with a top surface of the first EL layer, a top surface of the second EL layer, and a top surface of the insulating layer.

[0020] In the above structure, it is preferable that a common layer including an electron injection layer and an electron transport layer is provided, and the common layer is in contact with the top surface of the first EL layer, the top surface of the second EL layer, and the top surface of the insulating layer.

[0021] In the above structure, it is preferable that the first light-emitting layer contains a light-emitting substance that emits light of one color selected from blue, purple, blue-purple, green, yellow-green, yellow, orange, and red, and the second light-emitting layer contains a light-emitting substance that emits light of another color selected from blue, purple, blue-purple, green, yellow-green, yellow, orange, and red.

[0022] One embodiment of the present invention is a display device having a plurality of pixels over a substrate, each of the plurality of pixels having a light-emitting element, the light-emitting element having a pixel electrode, an EL layer over the pixel electrode, and a common electrode over the EL layer, the common electrode in the plurality of pixels being shared by each of the light-emitting elements in the plurality of pixels, the pixel electrodes of adjacent pixels in the plurality of pixels being separated by a first insulating layer containing an inorganic material and a second insulating layer containing an organic material, side surfaces of the pixel electrode and side surfaces of the EL layer having regions in contact with the first insulating layer, and the second insulating layer being on and in contact with the first insulating layer and disposed below the common electrode.

[0023] One embodiment of the present invention is a display device including a first pixel and a second pixel arranged adjacent to the first pixel. The first pixel includes a first light-emitting element having a first pixel electrode, a first EL layer over the first pixel electrode, and a common electrode over the first EL layer. The second pixel includes a second light-emitting element having a second pixel electrode, a second EL layer over the second pixel electrode, and a common electrode over the second EL layer. Side surfaces of the first pixel electrode, the first EL layer, the second pixel electrode, and the second EL layer have regions in contact with a first insulating layer. The display device also includes a second insulating layer provided on and in contact with the first insulating layer and arranged below the common electrode. The first insulating layer includes an inorganic material, and the second insulating layer includes an organic material.

[0024] One embodiment of the present invention is a display device including a first pixel and a second pixel arranged adjacent to the first pixel, the first pixel including a first light-emitting element having a first pixel electrode, a first EL layer over the first pixel electrode, and a common electrode over the first EL layer, and the second pixel including a second pixel electrode, a second EL layer over the second pixel electrode, and a common electrode over the second EL layer, the display device including a side surface of the first pixel electrode and a first light-emitting element having a first EL layer over the first pixel electrode and a common electrode over the second EL layer. The display device has a side surface of the EL layer, a side surface of the second pixel electrode, and a side surface of the second EL layer that have regions in contact with a first insulating layer, a second insulating layer that is provided on and in contact with the first insulating layer and is arranged below a common electrode, the first insulating layer having an inorganic material, and the second insulating layer having an organic material, and the top surface of the first EL layer, the top surface of the second EL layer, the top surface of the first insulating layer, and the top surface of the second insulating layer have regions in contact with the common electrode.

[0025] One embodiment of the present invention provides a display device including a first pixel and a second pixel arranged adjacent to the first pixel, the first pixel including a first light-emitting element having a first pixel electrode, a first EL layer over the first pixel electrode, a common layer over the first EL layer, and a common electrode over the common layer, and the second pixel including a second light-emitting element having a second pixel electrode, a second EL layer over the second pixel electrode, a common layer over the second EL layer, and a common electrode over the common layer, The display device has a side surface of the pixel electrode, a side surface of the first EL layer, a side surface of the second pixel electrode, and a side surface of the second EL layer each having an area in contact with a first insulating layer, a second insulating layer provided on and in contact with the first insulating layer and arranged below a common electrode, the first insulating layer having an inorganic material, the second insulating layer having an organic material, and an upper surface of the first EL layer, an upper surface of the second EL layer, an upper surface of the first insulating layer, and an upper surface of the second insulating layer each having an area in contact with a common layer.

[0026] In the above, in a cross-sectional view of the display device, the first insulating layer may have a region that protrudes above an upper surface of the first EL layer or an upper surface of the second EL layer.

[0027] Alternatively, in the above, the first EL layer or the second EL layer may have a region that protrudes above an upper surface of the first insulating layer in a cross-sectional view of the display device.

[0028] Alternatively, in the above, the upper surface of the second insulating layer may have a concave curved shape in a cross-sectional view of the display device.

[0029] Alternatively, in the above, the upper surface of the second insulating layer may have a convex curved shape in a cross-sectional view of the display device.

[0030] According to one embodiment of the present invention, a display device with high display quality can be provided. Furthermore, a highly reliable display device can be provided. Furthermore, a display device with low power consumption can be provided. Furthermore, a display device that can easily achieve high resolution can be provided. Furthermore, a display device that combines high display quality and high resolution can be provided. Furthermore, a display device with high contrast can be provided.

[0031] According to one embodiment of the present invention, a display device having a novel structure or a manufacturing method of the display device can be provided. Also, a method for manufacturing the above-described display device with high yield can be provided. According to one embodiment of the present invention, at least one of the problems of the prior art can be alleviated.

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

[0033] FIGS. 1A to 1C are diagrams showing a structural example of a display device. FIGS. 2A and 2B are diagrams showing a structural example of a display device. FIGS. 3A to 3F are diagrams showing a manufacturing method example of a display device. FIGS. 4A to 4E are diagrams showing a manufacturing method example of a display device and a structural example of a display device. FIGS. 5A to 5E are diagrams showing a manufacturing method example of a display device and a structural example of a display device. FIGS. 6A to 6C are diagrams showing a manufacturing method example of a display device. FIG. 6D is a diagram showing a structural example of a display device. FIGS. 7A and 7B are diagrams showing a structural example of a display device. FIGS. 8A and 8B are diagrams showing a manufacturing method example of a display device. FIG. 8C is a diagram showing a structural example of a display device. FIGS. 9A and 9B are diagrams showing a structural example of a display device. FIGS. 10A and 10B are diagrams showing a structural example of a display device. FIGS. 11A and 11B are diagrams showing a structural example of a display device. FIGS. 12A and 12B are diagrams showing a structural example of a display device. FIGS. 13A to 13F are diagrams showing a manufacturing method example of a display device. 14A to 14F are diagrams illustrating an example of a method for manufacturing a display device. FIGS. 15A to 15F are diagrams illustrating an example of a method for manufacturing a display device and a structural example of the display device. FIGS. 16A and 16B are diagrams illustrating a structural example of a display device. FIGS. 17A to 17C are diagrams illustrating a structural example of a display device. FIGS. 18A to 18C are diagrams illustrating a structural example of a display device. FIGS. 19A to 19D are diagrams illustrating a structural example of a display device. FIGS. 20A and 20B are diagrams illustrating a structural example of a display device. FIG. 21 is a perspective view illustrating an example of a display device. FIG. 22 is a cross-sectional view illustrating an example of a display device. 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 cross-sectional view illustrating an example of a display device. FIG. 26B is a cross-sectional view illustrating an example of a transistor. FIG. 27 is a cross-sectional view illustrating an example of a display device. FIGS. 28A and 28B are perspective views illustrating an example of a display module. FIG. 29 is a cross-sectional view illustrating an example of a display device. FIG. 30 is a cross-sectional view illustrating an example of a display device. 31, 32, and 33 are cross-sectional views showing an example of a display device.Fig. 34 is a cross-sectional view showing an example of a display device. Figs. 35A to 35D are diagrams showing configuration examples of light-emitting elements. Figs. 36A and 36B are diagrams showing an example of an electronic device. Figs. 37A to 37D are diagrams showing an example of an electronic device. Figs. 38A to 38F are diagrams showing an example of an electronic device. Figs. 39A to 39F are diagrams showing an example of an electronic device.

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

[0035] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0036] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0037] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0038] Furthermore, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" and "insulating layer" may be interchangeable with the terms "conductive film" and "insulating film."

[0039] In this specification, the EL layer refers to a layer provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance (also referred to as a light-emitting layer), or a stack including a light-emitting layer.

[0040] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting) an image or the like on a display surface, and therefore the display panel is one aspect of an output device.

[0041] In addition, in this specification, a display panel having a connector such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) attached to the substrate, or a display panel having an IC mounted on the substrate using a COG (Chip On Glass) method or the like, may be referred to as a display panel module, a display module, or simply a display panel.

[0042] A light-emitting element of one embodiment of the present invention may include a layer containing a substance with a high hole-injection property, a substance with a high hole-transport property, a substance with a high electron-transport property, a substance with a high electron-injection property, a bipolar substance, or the like.

[0043] The light-emitting layer and the layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a substance with high electron-transport properties, a substance with high electron-injection properties, a bipolar substance, or the like may each contain an inorganic compound such as quantum dots or a polymer compound (oligomer, dendrimer, polymer, or the like). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

[0044] Examples of quantum dot materials that can be used include colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, and core quantum dot materials. Materials containing elements from groups 12 and 16, 13 and 15, or 14 and 16 may also be used. Alternatively, quantum dot materials containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, and aluminum may also be used.

[0045] 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.

[0046] In this specification and the like, a structure in which different light-emitting layers are formed 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. In this specification and the like, a light-emitting device that can emit white light may be referred to as a white light-emitting device. In addition, a white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0047] Furthermore, light-emitting devices can be broadly divided into single structures and tandem structures. A single-structure device has one light-emitting unit between a pair of electrodes, and the light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, two or more light-emitting layers may be selected so that the light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration in which the entire light-emitting device emits white light can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0048] 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 an intermediate layer such as a charge-generating layer between the light-emitting units.

[0049] 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.

[0050] Embodiment 1 In this embodiment, a structural example of a display device according to one embodiment of the present invention and an example of a manufacturing method of the display device will be described.

[0051] One embodiment of the present invention is a display device having a light-emitting element (also referred to as a light-emitting device). The display device has at least two light-emitting elements that emit light of different colors. Each light-emitting element has a pair of electrodes and an EL layer therebetween. As the light-emitting element, an electroluminescent element such as an organic EL element or an inorganic EL element can be used. Alternatively, a light-emitting diode (LED) can be used. The light-emitting element of one embodiment of the present invention is preferably an organic EL element (organic electroluminescent element). Two or more light-emitting elements that emit light of different colors each have an EL layer containing a different material. For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0052] Here, when creating separate EL layers for light-emitting elements of different colors, it is known to form them by vapor deposition using a shadow mask such as a metal mask. However, this method makes it difficult to achieve high resolution and a high aperture ratio because the shape and position of the island-shaped organic film can deviate 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 deposited film due to vapor scattering. Furthermore, during vapor deposition, debris may be generated due to material adhering to the metal mask. Such debris may cause pattern defects in the light-emitting elements. Furthermore, the debris may cause short circuits. Furthermore, a process of cleaning the material adhering to the metal mask is required. Therefore, measures have been taken to artificially increase the resolution (also known as pixel density) by applying special pixel arrangement methods such as a pentile arrangement.

[0053] In one embodiment of the present invention, an EL layer is processed into a fine pattern without using a shadow mask such as a metal mask. This makes it possible to realize a display device with high definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, because the EL layer can be individually fabricated, a display device with extremely vivid, high contrast, and high display quality can be realized.

[0054] For simplicity, the following description will be given of the case where EL layers for two color light-emitting elements are formed separately. First, a first EL film and a first sacrificial film are laminated to cover the pixel electrodes. Next, a resist mask is formed on the first sacrificial film. Next, a portion of the first sacrificial film and a portion of the first EL film are etched using the resist mask to form the first EL layer and the first sacrificial layer on the first EL layer.

[0055] Next, a second EL film and a second sacrificial film are stacked and formed. Next, a resist mask is used to etch a portion of the second sacrificial film and a portion of the second EL film to form a second EL layer and a second sacrificial layer on the second EL layer. Next, the pixel electrodes are processed using the first sacrificial layer and the second sacrificial layer as masks to form a first pixel electrode overlapping the first EL layer and a second pixel electrode overlapping the second EL layer. In this manner, the first EL layer and the second EL layer can be separately formed. Finally, the first sacrificial layer and the second sacrificial layer are removed, and a common electrode is formed, thereby separately forming two-color light-emitting elements.

[0056] Furthermore, by repeating the above process, EL layers for light emitting elements of three or more colors can be produced separately, and a display device having light emitting elements of three or four or more colors can be realized.

[0057] At the edge of the EL layer, a step occurs between the area where the pixel electrode and the EL layer are provided and the area where the pixel electrode and the EL layer are not provided. When forming a common electrode on the EL layer, the step at the edge of the EL layer may reduce the coverage of the common electrode, which may lead to the common electrode being cut off. In addition, the common electrode may become thinner, which may increase the electrical resistance.

[0058] Furthermore, when the edge of the pixel electrode is roughly aligned with the edge of the EL layer, and when the edge of the pixel electrode is located outside the edge of the EL layer, the common electrode and the pixel electrode may short-circuit when the common electrode is formed on the EL layer.

[0059] In one embodiment of the present invention, by providing an insulating layer between the first EL layer and the second EL layer, unevenness of the surface on which the common electrode is provided can be reduced. Therefore, coverage of the edge of the first EL layer and the edge of the second EL layer with the common electrode can be improved, and good conductivity of the common electrode can be achieved. In addition, short-circuiting between the common electrode and the pixel electrode can be suppressed.

[0060] In one embodiment of the present invention, a sacrificial layer is formed using a resist mask, and the EL layer and the pixel electrode can be processed using the formed sacrificial layer. Therefore, a light-emitting element can be formed without using different resist masks for processing the pixel electrode and the EL layer. Therefore, a light-emitting element can be formed without providing a positional margin between the edge of the pixel electrode and the EL layer. By reducing the positional margin, the light-emitting region can be widened, thereby increasing the aperture ratio of the light-emitting element. Furthermore, by reducing the positional margin, the pixel size can be reduced, thereby enabling a display device with high resolution. Furthermore, the number of times a resist mask is used can be reduced, thereby simplifying the process, reducing costs, and improving yield.

[0061] When EL layers of different colors are adjacent, it is difficult to achieve a spacing of less than 10 μm using a formation method using, for example, a metal mask. However, the above method can narrow the spacing to 3 μm or less, 2 μm or less, or even 1 μm or less. For example, by using 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 elements, 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%.

[0062] Furthermore, the pattern of the EL layer itself can be made much smaller than when a metal mask is used. Furthermore, for example, when a metal mask is used to separately form an EL layer, thickness variations occur between the center and edges of the pattern, resulting in a smaller effective area that can be used as the light-emitting region relative to the overall area of ​​the pattern. On the other hand, with the above-described fabrication method, a pattern is formed by processing a film deposited to a uniform thickness, making it possible to achieve a uniform thickness within the pattern, and even with a fine pattern, almost the entire area can be used as the light-emitting region. Therefore, the above-described fabrication method can achieve both high definition and a high aperture ratio.

[0063] In this way, according to the above-described manufacturing method, a display device integrating minute light-emitting elements can be realized, and therefore there is no need to apply a special pixel arrangement method such as a pen tile method to artificially increase the resolution. Therefore, it is possible to realize a display device with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, and with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, or even 3000 ppi or more, or even 5000 ppi or more.

[0064] Below, a more specific example of a structure and an example of a manufacturing method of a display device of one embodiment of the present invention will be described with reference to the drawings.

[0065] <Structure Having Insulating Layer 131> Structural examples of a display device according to one embodiment of the present invention will be described below with reference to FIGS. 1A to 1C, 2A and 2B, 10A and 10B, and the like.

[0066] 1A shows a schematic top view of a display device 100 according to one embodiment of the present invention. The display device 100 includes a plurality of light-emitting elements 110R that emit red light, a plurality of light-emitting elements 110G that emit green light, and a plurality of light-emitting elements 110B that emit blue light. In FIG. 1A, the light-emitting regions of the light-emitting elements are labeled with R, G, and B to easily distinguish the light-emitting elements from one another.

[0067] The light emitting elements 110R, 110G, and 110B are arranged in a matrix. Fig. 1A shows a so-called stripe arrangement in which light emitting elements of the same color are arranged in one direction. Note that the arrangement of the light emitting elements is not limited to this, and arrangements such as a delta arrangement or a zigzag arrangement may also be used, or a pentile arrangement may also be used.

[0068] As the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B, it is preferable to use an EL element such as an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode). Examples of light-emitting materials that the EL elements have include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and materials that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials).

[0069] 1B is a schematic cross-sectional view corresponding to the dashed dotted line A1-A2 in FIG. 1A, and FIG. 1C is a schematic cross-sectional view corresponding to the dashed dotted line B1-B2.

[0070] The light-emitting device 100 has a light-emitting element 110R, a light-emitting element 110G, and a light-emitting element 110B on a substrate. FIG. 1B shows cross sections of the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B. The light-emitting element 110R has a pixel electrode 111R, an EL layer 112R, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an EL layer 112G, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an EL layer 112B, and a common electrode 113.

[0071] The light-emitting element 110R has an EL layer 112R between the pixel electrode 111R and the common electrode 113. The EL layer 112R contains a light-emitting organic compound that emits light having an intensity in at least the red wavelength range. The light-emitting element 110G has an EL layer 112G between the pixel electrode 111G and the common electrode 113. The EL layer 112G contains a light-emitting organic compound that emits light having an intensity in at least the green wavelength range. The light-emitting element 110B has an EL layer 112B between the pixel electrode 111B and the common electrode 113. The EL layer 112B contains a light-emitting organic compound that emits light having an intensity in at least the blue wavelength range.

[0072] The EL layer 112R, the EL layer 112G, and the EL layer 112B each include a layer (light-emitting layer) containing a light-emitting organic compound. The light-emitting layer may include one or more compounds (host material, assist material) in addition to a light-emitting substance (guest material). As the host material and the assist material, one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) can be selected and used. As the host material and the assist material, it is preferable to use a combination of compounds that form an exciplex. In order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole-transporting material) with a compound that easily accepts electrons (electron-transporting material).

[0073] The light-emitting element can be made of either a low molecular weight compound or a high molecular weight compound, and may contain an inorganic compound (such as a quantum dot material).

[0074] Each of the EL layers 112R, 112G, and 112B may have one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer in addition to a light-emitting layer.

[0075] The pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B are provided for each light-emitting element. The common electrode 113 is provided as a continuous layer common to each light-emitting element. A conductive film transmissive to visible light is used for either one of the pixel electrodes or the common electrode 113, and a conductive film reflective to visible light is used for the other. By making each pixel electrode transmissive and the common electrode 113 reflective, a bottom-emission display device can be obtained. Conversely, by making each pixel electrode reflective and the common electrode 113 transmissive, a top-emission display device can be obtained. Note that by making both the pixel electrodes and the common electrode 113 transmissive, a dual-emission display device can be obtained.

[0076] In the following, when describing matters common to the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B, the symbols added to the reference numerals may be omitted and the light-emitting element may be referred to as the light-emitting element 110. Similarly, the pixel electrodes 111R, 111G, and 111B may be referred to as the pixel electrodes 111. Similarly, the EL layers 112R, 112G, and 112B may be referred to as the EL layers 112. The same applies to the other layers.

[0077] An insulating layer 131 is provided between adjacent light-emitting elements 110. The insulating layer 131 is located between the EL layers 112 of the light-emitting elements 110. In addition, a common electrode 113 is provided on the insulating layer 131.

[0078] For example, the insulating layer 131 is provided between two EL layers 112 that exhibit different colors. Alternatively, the insulating layer 131 is provided between two EL layers 112 that exhibit the same color. Alternatively, a configuration may be adopted in which the insulating layer 131 is provided between two EL layers 112 that exhibit different colors, but not between two EL layers 112 that exhibit the same color.

[0079] The insulating layer 131 is provided, for example, between two EL layers 112 when viewed from above.

[0080] Each of the EL layers 112R, 112G, and 112B preferably has a region in contact with the upper surface of the pixel electrode and a region in contact with the side surface of the insulating layer 131. The ends of the EL layers 112R, 112G, and 112B preferably contact the side surface of the insulating layer 131.

[0081] By providing the insulating layer 131 between the light-emitting elements of different colors, the EL layer 112R, the EL layer 112G, and the EL layer 112G can be prevented from contacting each other. This can effectively prevent current from flowing through two adjacent EL layers, thereby preventing unintended light emission. As a result, contrast can be improved, and a display device with high display quality can be realized.

[0082] The top surface of the insulating layer 131 is preferably substantially flush with the top surface of the EL layer 112. The top surface of the insulating layer 131 has, for example, a flat shape.

[0083] In addition, the upper surface of the insulating layer 131 may be higher than the upper surface of the EL layer 112 (see, for example, FIG. 6C described later) or may be lower than the upper surface of the EL layer 112 (see, for example, FIG. 7A described later).

[0084] The upper surface of the insulating layer 131 may have a concave portion (see, for example, FIG. 8B described later), or may have a convex portion (see, for example, FIG. 9A described later).

[0085] The difference in height between the top surface of the insulating layer 131 and the top surface of the EL layer 112 is preferably, for example, 0.5 times or less the thickness of the insulating layer 131, and more preferably 0.3 times or less the thickness of the insulating layer 131. Alternatively, for example, the insulating layer 131 may be provided so that the top surface of the EL layer 112 is higher than the top surface of the insulating layer 131. Alternatively, for example, the insulating layer 131 may be provided so that the top surface of the insulating layer is higher than the top surface of the light-emitting layer included in the EL layer 112. The thickness of the insulating layer 131 is, for example, approximately the same as the thickness from the bottom surface of the pixel electrode 111 to the top surface of the EL layer 112. The thickness of the insulating layer 131 is preferably, for example, 0.3 times or more, 0.5 times or more, or 0.7 times or more the thickness from the bottom surface of the pixel electrode 111 to the top surface of the EL layer 112.

[0086] Examples of materials for the insulating layer 131 include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene-based resin, phenol resin, and precursors of these resins.

[0087] Furthermore, a protective layer 121 is provided on the common electrode 113 to cover the light emitting elements 110R, 110G, and 110B. The protective layer 121 has a function of preventing impurities such as water from diffusing from above into each light emitting element.

[0088] The protective layer 121 may have, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, the protective layer 121 may be made of a semiconductor material such as indium gallium oxide or indium gallium zinc oxide.

[0089] Alternatively, the protective layer 121 may be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, thereby improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 121 is flat, it is preferable that when a structure (e.g., a color filter, a touch sensor electrode, a lens array, etc.) is provided above the protective layer 121, the influence of uneven shapes caused by the structure below can be reduced.

[0090] [Configuration Example 2] Display device 100A shown in Figures 2A and 2B differs from display device 100 shown in Figures 1B and 1C mainly in that it has a common layer 114. Figure 2A is a schematic cross-sectional view corresponding to dashed dotted line A1-A2 in Figure 1A, and Figure 2B is a schematic cross-sectional view corresponding to dashed dotted line B1-B2.

[0091] The common layer 114, like the common electrode 113, is provided across a plurality of light-emitting elements. The common layer 114 is provided to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B. The structure including the common layer 114 can simplify the manufacturing process and reduce manufacturing costs. The common layer 114 and the common electrode 113 can be formed successively without any process such as etching therebetween. Therefore, the interface between the common layer 114 and the common electrode can be made clean, and good characteristics can be obtained in the light-emitting element.

[0092] The common layer 114 preferably contacts one or more of the top surfaces of the EL layer 112R, the EL layer 112G, and the EL layer 112B.

[0093] Preferably, each of the EL layers 112R, 112G, and 112B has a light-emitting layer containing a light-emitting material that emits light of at least one color. The common layer 114 is preferably a layer that includes one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. In a light-emitting element in which the pixel electrode serves as the anode and the common electrode serves as the cathode, the common layer 114 may include an electron injection layer or may include both an electron injection layer and an electron transport layer.

[0094] [Configuration Example 3] In each light-emitting element, by using a microcavity structure (a microresonator structure) to vary the optical path length, it is possible to intensify light of a specific wavelength, thereby realizing a display device with improved color purity.

[0095] For example, a microcavity structure can be realized by varying the thickness of the EL layer 112 in each light-emitting element. For example, the EL layer 112R of the light-emitting element 110R that emits light with the longest wavelength can be configured to be the thickest, and the EL layer 112B of the light-emitting element 110B that emits light with the shortest wavelength can be configured to be the thinnest. However, this is not limited to this, and the thickness of each EL layer can be adjusted taking into consideration the wavelength of light emitted by each light-emitting element, the optical characteristics of the layers that make up the light-emitting element, and the electrical characteristics of the light-emitting element.

[0096] Furthermore, for example, a layer that is transmissive to visible light can be used as the optical adjustment layer to make the optical path length different for each light-emitting element. For example, an optical adjustment layer may be provided between the pixel electrode 111 and the EL layer 112. For example, a conductive material that is transmissive to visible light can be used as the optical adjustment layer. For example, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, indium tin oxide containing silicon, and indium zinc oxide containing silicon can be used.

[0097] Each optical adjustment layer can be formed after forming the conductive films that will become the pixel electrodes 111R, 111G, and 111B, but before forming the EL film 112Rf shown in FIG. 13A (to be described later) and the like. By varying the thickness of each optical adjustment layer, the optical path length can be varied in each light-emitting element. Each optical adjustment layer may use a conductive film of a different thickness, or may have a single-layer structure, a two-layer structure, a three-layer structure, or the like, in order of thinnest to thickest.

[0098] Alternatively, an optical adjustment layer and an EL layer having a different thickness for each color may be used in combination.

[0099] For example, the thicknesses of the optical adjustment layer and the EL layer may be adjusted so that the total thickness of the optical adjustment layer and the EL layer of each light-emitting element is approximately equal. In this case, the surface on which the common electrode 113 is formed can be made more flat.

[0100] 10A , the light-emitting element 110R has an optical adjustment layer 115R between the pixel electrode 111R and the EL layer 112R. The light-emitting element 110G has an optical adjustment layer 115G between the pixel electrode 111G and the EL layer 112G. The light-emitting element 110B has an optical adjustment layer 115B between the pixel electrode 111B and the EL layer 112B.

[0101] The display device 100C shown in FIG. 10B differs from the display device 100B shown in FIG. 10A mainly in that the display device 100C has a common layer 114 between the EL layer 112 and the common electrode 113, which means that the configuration of the light-emitting element is different.

[0102] [Manufacturing Method Example 1] An example of a manufacturing method of a display device according to one embodiment of the present invention will be described below with reference to the drawings. Here, the display device 100A shown in the above configuration example will be described as an example. FIGS. 3A to 4E are schematic cross-sectional views illustrating steps in the manufacturing method of the display device exemplified below.

[0103] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an atomic layer deposition (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.

[0104] 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 method, slit coating, roll coating, curtain coating, knife coating, etc.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0109] [Preparation of Substrate 101] A substrate having heat resistance sufficient to withstand at least the subsequent heat treatment can be used as the substrate 101. When an insulating substrate is used as the substrate 101, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like can be used. In addition, a semiconductor substrate such as a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or an SOI substrate can be used.

[0110] In particular, it is preferable to use a substrate in which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or insulating substrate as the substrate 101. The semiconductor circuit preferably constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), etc. In addition to the above, an arithmetic circuit, a memory circuit, etc. may also be configured.

[0111] Subsequently, a conductive film 111 f that will become the pixel electrode 111 is formed on the substrate 101 .

[0112] When a conductive film reflective to visible light is used as the pixel electrode, it is preferable to use a material (such as silver or aluminum) with as high a reflectance as possible over the entire wavelength range of visible light, which not only increases the light extraction efficiency of the light-emitting element but also improves color reproducibility.

[0113] [Formation of EL Film 112Rf] Subsequently, an EL film 112Rf, which will later become the EL layer 112R, is formed on the conductive film 111f.

[0114] The EL film 112Rf includes a film containing at least a light-emitting compound. Alternatively, the EL film 112Rf may have a structure in which one or more of films functioning as an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, or a hole injection layer are stacked. The EL film 112Rf can be formed by, for example, a vapor deposition method, a sputtering method, an inkjet method, or the like. However, the EL film 112Rf is not limited to these methods, and the above-described film formation methods can be used as appropriate.

[0115] [Formation of Sacrificial Film 144a] Subsequently, the sacrificial film 144a is formed to cover the EL film 112Rf.

[0116] The sacrificial film 144a can be formed by, for example, sputtering, ALD (thermal ALD, PEALD), or vacuum evaporation. A formation method that causes less damage to the EL layer is preferable, and it is more suitable to form the first sacrificial film 144a by ALD or vacuum evaporation than by sputtering. Furthermore, using aluminum oxide as the sacrificial film 144a is particularly suitable because it can reduce manufacturing costs. Furthermore, the ALD method can cause less film formation damage to the underlying layer than the sputtering method.

[0117] The sacrificial film 144a can be a film that is highly resistant to the etching process of each EL film, such as the EL film 112Rf, i.e., a film with a high etching selectivity. The sacrificial film 144a can also be a film that has a high etching selectivity with respect to a protective film, such as the protective film 146a described below. Furthermore, the sacrificial film 144a can be a film that can be removed by a wet etching method that causes minimal damage to each EL film. When using the wet etching method, 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.

[0118] The sacrificial film 144a may be, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic film such as an inorganic insulating film.

[0119] The sacrificial film 144a may be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, 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.

[0120] The sacrificial film 144a may be made of a metal oxide such as indium gallium zinc oxide (In—Ga—Zn oxide, also referred to as IGZO). Other examples include indium oxide, indium zinc oxide (In—Zn oxide), indium tin oxide (In—Sn oxide), indium titanium oxide (In—Ti oxide), indium tin zinc oxide (In—Sn—Zn oxide), indium titanium zinc oxide (In—Ti—Zn oxide), and indium gallium tin zinc oxide (In—Ga—Sn—Zn oxide). Alternatively, indium tin oxide containing silicon may be used.

[0121] The present invention can also be applied to a case where, instead of the gallium, an element M (wherein M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) is used. In particular, it is preferable that M is one or more elements selected from gallium, aluminum, and yttrium.

[0122] The sacrificial film 144a can be made of an inorganic insulating material such as aluminum oxide, hafnium oxide, silicon oxide, etc. In particular, it is preferable to form an aluminum oxide film as the sacrificial film 144a by the ALD method, since this can reduce damage to the base (particularly the EL layer, etc.).

[0123] The sacrificial film 144 a may have a single layer structure or a laminated structure of two or more layers, such as a two-layer structure of an In—Ga—Zn oxide formed by sputtering and a silicon nitride film formed by sputtering, a two-layer structure of an In—Ga—Zn oxide formed by sputtering and aluminum oxide formed by ALD, or a two-layer structure of aluminum oxide formed by ALD and In—Ga—Zn oxide formed by sputtering.

[0124] Note that when the sacrificial film 144a is formed by the ALD method or the sputtering method, it may be configured to be heated. In this configuration, it is preferable that the base material (here, the EL film 112Rf) is not deteriorated, and the substrate temperature during the formation of the sacrificial film 144a may be set to a temperature of room temperature or higher and 200°C or lower, preferably 50°C or higher and 150°C or lower, more preferably 70°C or higher and 100°C or lower, typically around 80°C. By using the above configuration, it is possible to improve the adhesion between the base material and the sacrificial film 144a.

[0125] The sacrificial film 144a does not necessarily have to be formed, and the protective film 146a may be formed on the EL film 112Rf so as to be in contact with it. The same applies to pixels that exhibit other colors.

[0126] [Formation of Protective Film 146a] Subsequently, the protective film 146a is formed on the sacrificial film 144a.

[0127] The protective film 146a is a film that is used as a hard mask when etching the sacrificial film 144a later. Furthermore, when processing the protective film 146a later, the sacrificial film 144a is exposed. Therefore, a combination of films that have a large etching selectivity relative to each other is selected for the sacrificial film 144a and the protective film 146a. Therefore, a film that can be used for the protective film 146a can be selected depending on the etching conditions for the sacrificial film 144a and the etching conditions for the protective film 146a.

[0128] For example, when dry etching using a gas containing fluorine (also referred to as a fluorine-based gas) is used to etch the protective film 146a, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, an alloy containing molybdenum and tungsten, or the like can be used for the protective film 146a. Here, examples of films that can achieve a large etching selectivity (i.e., a slower etching rate) compared to dry etching using the fluorine-based gas include metal oxide films such as IGZO and ITO, which can be used for the sacrificial film 144a.

[0129] However, the protective film 146a is not limited to this, and can be selected from various materials depending on the etching conditions of the sacrificial film 144a and the etching conditions of the protective film 146a. For example, it can be selected from the films that can be used for the sacrificial film 144a.

[0130] The protective film 146a may be, for example, a nitride film, such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, or germanium nitride.

[0131] Alternatively, the protective film 146a may be an organic film that can be used for the EL film 112Rf, etc. For example, the same organic film as that used for the EL film 112Rf, EL film 112Gf, or EL film 112Bf may be used for the protective film 146a. Using such an organic film is preferable because it allows the same film-forming equipment to be used for the EL film 112Rf, etc.

[0132] [Formation of Resist Mask 143a] Subsequently, a resist mask 143a is formed on the protective film 146a (FIG. 3A).

[0133] The resist mask 143a can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0134] Here, if the resist mask 143a is formed on the sacrificial film 144a without the protective film 146a, there is a risk that the EL film 112Rf will be dissolved by the solvent of the resist material if there are defects such as pinholes in the sacrificial film 144a. By using the protective film 146a, it is possible to prevent such problems from occurring.

[0135] [Etching of Protective Film 146a] Subsequently, a portion of the protective film 146a that is not covered by the resist mask 143a is removed by etching to form island-shaped or strip-shaped protective layers 147a.

[0136] When etching the protective film 146a, it is preferable to use etching conditions with a high selectivity so that the sacrificial film 144a is not removed by the etching. The protective film 146a can be etched by wet etching or dry etching, but using dry etching can prevent the pattern of the protective film 146a from shrinking.

[0137] [Removal of Resist Mask 143a] Subsequently, the resist mask 143a is removed.

[0138] The resist mask 143a can be removed by wet etching or dry etching. In particular, the resist mask 143a is preferably removed by dry etching (also called plasma ashing) using oxygen gas as an etching gas.

[0139] At this time, the removal of the resist mask 143a is performed in a state where the EL film 112Rf is covered with the sacrificial film 144a, so that the influence on the EL film 112Rf is suppressed. In particular, if the EL film 112Rf comes into contact with oxygen, it may have an adverse effect on the electrical characteristics, so this is suitable when performing etching using oxygen gas, such as plasma ashing.

[0140] [Etching of Sacrificial Film 144a] Subsequently, using the protective layer 147a as a mask, the part of the sacrificial film 144a that is not covered by the protective layer 147a is removed by etching to form island-shaped or strip-shaped sacrificial layers 145a.

[0141] The sacrificial film 144a can be etched by wet etching or dry etching, but dry etching is preferable because it can prevent the pattern from shrinking.

[0142] [Etching of EL Film 112Rf] Subsequently, a part of the EL film 112Rf that is not covered with the sacrificial layer 145a is removed by etching to form island-shaped or strip-shaped EL layers 112R (FIG. 3B).

[0143] For etching the EL film 112Rf, it is preferable to use dry etching using an etching gas that does not contain oxygen as a main component. This makes it possible to suppress the deterioration of the EL film 112Rf and realize a highly reliable display device. As an etching gas that does not contain oxygen as a main component, for example, CF ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３Examples of the etching gas include a noble gas such as He or a noble gas such as He. A mixed gas of the above gas and a dilution gas that does not contain oxygen can also be used as the etching gas. Here, the protective layer 147a may be removed during the etching of the EL film 112Rf.

[0144] [Formation of EL Layer 112G and EL Layer 112B] Subsequently, an EL film 112Gf that will become the EL layer 112G is formed on the sacrificial layer 145a, the protective layer 147a, and the exposed conductive film 111f. For the EL film 112Gf, the description of the EL film 112Rf can be referred to.

[0145] Next, a sacrificial film 144b is formed on the EL film 112Gf, and a protective film 146b is formed on the sacrificial film 144b. The description of the sacrificial film 144a can be referred to for the sacrificial film 144b. The description of the protective film 146a can be referred to for the protective film 146b.

[0146] Subsequently, a resist mask 143b is formed on the protective film 146b (FIG. 3C).

[0147] Subsequently, the protective film 146b is etched using the resist mask 143b to form a protective layer 147b, and then the resist mask 143b is removed.

[0148] Subsequently, the sacrificial film 144b and the EL film 112Gf are etched using the protective layer 147b as a mask to form the sacrificial layer 145b and the EL layer 112Gf (FIG. 3D).

[0149] Subsequently, an EL film 112Bf to be the EL layer 112B is formed on the sacrificial layer 145a, the sacrificial layer 145b, the protective layer 147a, the protective layer 147b, and the exposed conductive film 111f. For the EL film 112Bf, the description of the EL film 112Rf can be referred to.

[0150] Next, a sacrificial film 144c is formed on the EL film 112Bf, and a protective film 146c is formed on the sacrificial film 144c. The description of the sacrificial film 144a can be referred to for the sacrificial film 144c. The description of the protective film 146a can be referred to for the protective film 146c.

[0151] Subsequently, a resist mask 143c is formed on the protective film 146c (FIG. 3E).

[0152] Subsequently, the protective film 146c is etched using the resist mask 143c to form a protective layer 147c, and then the resist mask 143c is removed.

[0153] Subsequently, the sacrificial film 144c and the EL film 112Bf are etched using the protective layer 147c as a mask to form the sacrificial layer 145c and the EL layer 112Bf (FIG. 3F).

[0154] [Formation of pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B] Subsequently, portions of the conductive film 111f that are not covered by the EL layer 112R, the EL layer 112G, the EL layer 112B, the sacrificial layer 145a, the sacrificial layer 145b, the sacrificial layer 145c, the protective layer 147a, the protective layer 147b, and the protective layer 147c are etched to form the pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B ( FIG. 4A ).

[0155] The conductive film 111f can be etched by wet etching or dry etching. Here, by using dry etching using an etching gas that does not contain oxygen as a main component as a condition for etching the conductive film 111f, damage to the EL layer 112 can be reduced. Furthermore, as will be described later with reference to FIGS. 5A to 5E , damage to the EL layer 112 can be reduced in some cases by forming the pixel electrodes 111R, 111G, and 111B in advance.

[0156] [Formation of Insulating Layer 131] Next, an insulating film 131f is formed to become the insulating layer 131 ( FIG. 4B ). The insulating film 131f is provided so as to cover the protective layer 147, the sacrificial layer 145, the EL layer 112, and the pixel electrodes 111. The insulating film 131f is preferably a planarizing film.

[0157] The insulating film 131f is preferably made of a resin, and is, for example, an organic insulating film.

[0158] Examples of materials that can be used for the insulating film 131f include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0159] Next, the insulating film 131f is etched to expose the upper surface of the protective layer 147 (FIG. 4C). The insulating film 131f is etched substantially uniformly across the upper surface of the insulating film 131f. This uniform etching and planarization is also called etch-back.

[0160] The insulating film 131f can be etched by dry etching or wet etching. Alternatively, the insulating film 131f may be etched by ashing using oxygen plasma or the like. Note that ashing using oxygen plasma has advantages such as high controllability, good in-plane uniformity, and suitability for processing using large substrates, and is therefore suitable for removing part of the insulating film 131f. Alternatively, chemical mechanical polishing (CMP) may be used to etch the insulating film 131f.

[0161] Note that when etching the insulating film 131f, it is preferable to suppress damage caused by etching to the EL layer 112. Therefore, for example, it is preferable to etch the insulating film 131f so that exposure of the side surfaces of the EL layer 112 is reduced.

[0162] Furthermore, by etching the insulating film 131f in a state where the sacrificial layer 145 is provided on the EL layer 112, damage to the upper surface of the EL layer 112 due to etching can be suppressed.

[0163] 4C , the insulating film 131f may be etched so that the upper surface of the insulating layer 131 is substantially flush with the upper surface of the EL layer 112. By providing the insulating layer 131 so that the upper surfaces of the insulating layer 131 and the EL layer are substantially flush with each other, when forming the common electrode 113 shown in FIG. 4E (to be described later), the unevenness of the surface on which the common electrode 113 is to be provided can be reduced, and coverage can be improved.

[0164] FIG. 4C shows an example in which the insulating layer 131 is formed so that the top and side surfaces of the protective layer 147 and the side surfaces of the sacrificial layer 145 are exposed.

[0165] The flatness of the surface of the insulating film 131f may change depending on the unevenness of the surface on which the insulating film 131f is formed and the density of the pattern formed on the surface on which the insulating film 131f is formed. In addition, the flatness of the insulating film 131f may change depending on the viscosity of the material used for the insulating film 131f.

[0166] For example, the insulating film 131f may be thinner in regions between the multiple EL layers 112 than in regions above the EL layers 112. In such a case, for example, by etching back the insulating film 131f, the height of the upper surface of the insulating layer 131 may become lower than the height of the upper surface of the protective layer 147 or the height of the upper surface of the sacrificial layer 145.

[0167] Furthermore, the insulating film 131f may have a recessed or bulged shape in the region between the plurality of EL layers 112.

[0168] 4C shows an example in which the insulating layer 131 is provided so that the top surface of the insulating layer 131 and the top surface of the EL layer are approximately flush with each other, but as will be described in detail later with reference to Figures 6A to 6D and the like, the insulating layer 131 may be provided so that the top surface of the insulating layer 131 is higher than the top surface of the EL layer 112. Alternatively, as will be described in detail later with reference to Figures 7A and 7B and the like, the insulating layer 131 may be provided so that the top surface of the insulating layer 131 is lower than the top surface of the EL layer 112.

[0169] The shape of the upper surface of the insulating layer 131 may have a recessed portion, as will be described in detail later in Figures 8A to 8C, etc. The shape of the upper surface of the insulating layer 131 may have a protruding portion, as will be described in detail later in Figures 9A and 9B, etc.

[0170] Furthermore, the shape and height of the upper surface of the insulating layer 131 may change due to the removal of the protective layer and the sacrificial layer shown in FIG. 4D, which will be described later.

[0171] [Removal of Protective Layer and Sacrificial Layer] Next, the protective layer 147a, the protective layer 147b, the protective layer 147c, the sacrificial layer 145a, the sacrificial layer 145b, and the sacrificial layer 145c are removed to expose the upper surfaces of the EL layer 112R, the EL layer 112G, and the EL layer 112B (Figure 4D).

[0172] 4D shows an example in which the insulating layer 131 is provided so that the height of the upper surface of the insulating layer 131 is approximately the same as the height of the upper surface of the EL layer 112. In Fig. 4D, the upper surface of the EL layer 112 is exposed, and the side surfaces of the EL layer 112 are covered with the insulating layer 131. Covering the side surfaces of the EL layer 112 with the insulating layer 131 can reduce damage to the EL layer when the protective layer 147 is etched.

[0173] The protective layers 147a, 147b, and 147c can be removed by wet etching or dry etching.

[0174] The sacrificial layers 145a, 145b, and 145c can be removed by wet etching or dry etching. At this time, it is preferable to use a method that causes as little damage as possible to the EL layers 112R, 112G, and 112B. In particular, it is preferable to use a wet etching method. For example, it is preferable to use wet etching using a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture of these. Using these wet etching conditions can reduce damage to the insulating layer, for example.

[0175] In this manner, the EL layer 112R, the EL layer 112G, and the EL layer 112B can be separately produced.

[0176] [Formation of Common Electrode 113] Subsequently, the common electrode 113 is formed to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B. The common electrode 113 can be formed by, for example, sputtering or vacuum deposition.

[0177] Through the above steps, the light emitting elements 110R, 110G, and 110B can be fabricated.

[0178] [Formation of Protective Layer 121] Next, the protective layer 121 is formed on the common electrode 113 ( FIG. 4E ). The inorganic insulating film used for the protective layer 121 is preferably formed by sputtering, PECVD, or ALD. The ALD method is particularly preferred because it has excellent step coverage and is less likely to cause defects such as pinholes. Furthermore, the inkjet method is preferably used to form the organic insulating film, because it allows for the formation of a uniform film in the desired area.

[0179] Through the above steps, the display device 100 shown in FIGS. 1B and 1C can be manufactured.

[0180] By using the above manufacturing method, process damage to the EL layers 112R, 112G, and 112B can be reduced, and therefore a display device with extremely high reliability can be realized.

[0181] [Formation of common layer 114] Before forming the common electrode 113, the common layer 114 is formed to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B, and then the common electrode 113 is formed, thereby making it possible to manufacture the display device 100A shown in Figures 2A and 2B.

[0182] [Modification of Configuration Example 1] The pixel electrodes 111R, 111G, and 111B may be formed before the EL film 112Rf is formed.

[0183] First, as shown in Fig. 5A, pixel electrodes 111R, 111G, and 111B are formed. Then, as described with reference to Figs. 3A to 3F, EL layers 112, sacrificial layers 145, and protective layers 147 corresponding to the light-emitting elements 110 are formed using a resist mask or the like (Fig. 5B). Then, an insulating layer 131 is formed (Fig. 5C), the sacrificial layer 145 and protective layer 147 are removed (Fig. 5D), and a common electrode 113 and protective layer 121 are formed, thereby obtaining the display device 100 shown in Fig. 5E.

[0184] 5E, the edge of the pixel electrode 111 is located outside the edge of the EL layer 112. In addition, on the upper surface of the pixel electrode 111, the edge and its vicinity are covered with an insulating layer 131.

[0185] [Structure Example 3] Note that the insulating layer 131 may be provided so that the top surface of the insulating layer 131 is higher than the top surface of the EL layer 112 .

[0186] The configuration shown in FIG. 6A differs from the configuration shown in FIG. 4C in that the insulating layer 131 is provided so that the top surface of the insulating layer 131 is higher than the top surface of the EL layer 112 .

[0187] In the configuration shown in FIG. 6A , the protective layer 147 and the sacrificial layer 145 are removed to obtain the configuration shown in FIG. 6B . In FIG. 6B , the insulating layer 131 is provided so that its upper surface is higher than the upper surface of the EL layer 112, and a portion of the side surface of the insulating layer 131 is exposed. Note that removing the protective layer 147 and the sacrificial layer 145 may etch a portion of the insulating layer 131, resulting in a change in the shape of the insulating layer 131. For example, the thickness of the insulating layer 131 may be reduced. Furthermore, for example, corners formed by the upper surface and side surface of the insulating layer 131 may be rounded. Furthermore, for example, the upper surface of the insulating layer 131 may change to a convex, concave, or other shape. Rounding the corners formed by the upper surface and side surface of the insulating layer 131 may improve the coverage of the common electrode 113 or the common layer 114.

[0188] In the step shown in Fig. 6B, the common electrode 113 and the protective layer 121 are formed to obtain the display device 100 shown in Fig. 6C. In addition, in the step shown in Fig. 6B, the common layer 114, the common electrode 113, and the protective layer 121 are formed to obtain the display device 100A shown in Fig. 6D.

[0189] By making the top surface of the insulating layer 131 higher than the top surface of the EL layer 112, the side surfaces of the EL layer 112 can be covered with the insulating layer 131. Therefore, damage to the EL layer 112 when the protective layer 147 is removed can be reduced.

[0190] Configuration Example 4 Furthermore, by providing the insulating layer 131 so that the top surface of the insulating layer 131 is lower than the top surface of the EL layer 112, the display device 100 shown in FIG. 7A and the display device 100A shown in FIG. 7B can be obtained.

[0191] By providing the insulating layer 131 so that the top surface of the insulating layer 131 is lower than the top surface of the EL layer 112, coverage of the common electrode 113 or the common layer 114 on the top surface of the EL layer 112 may be improved.

[0192] Configuration Example 5 The top surface of the insulating layer 131 may have a recess.

[0193] 8A shows the structure after etching back the insulating film 131f. As shown in Fig. 8A, the shape of the top surface of the insulating layer 131 formed by the etch back may have a recess. For example, the shape of the top surface of the insulating layer 131 has a gentle depression.

[0194] In the configuration of Fig. 8A, a common electrode 113 and a protective layer 121 are formed to obtain the display device 100 shown in Fig. 8B. Alternatively, in the configuration of Fig. 8A, a common layer 114, a common electrode 113, and a protective layer 121 are formed to obtain the display device 100A shown in Fig. 8C.

[0195] Configuration Example 6 The shape of the upper surface of the insulating layer 131 may have a convex portion. The shape of the upper surface of the insulating layer 131 shown in Figures 9A and 9B has a gently curved surface that is convex upward.

[0196] In the display device 100 shown in Fig. 9A, a common electrode 113 is provided on the EL layer 112 and an insulating layer 131 provided between the EL layers and having a convex upper surface. In the display device 100 shown in Fig. 9B, a common layer 114 is provided on the EL layer 112 and an insulating layer 131 provided between the EL layers and having a convex upper surface.

[0197] <Structure Including Insulating Layer 131 and Insulating Layer 130> Structural examples of the display device of one embodiment of the present invention will be described below with reference to FIGS. 11A and 11B, 12A and 12B, 20A and 20B, and the like.

[0198] [Configuration Example 1-2] Hereinafter, a configuration will be described in which the display device 100 has an insulating layer 130 in addition to the insulating layer 131 described above as an insulating layer provided between adjacent light-emitting elements.

[0199] The display device 100 shown in Fig. 11A differs from Fig. 1B etc. in that it has an insulating layer 130. Fig. 11A is a schematic cross-sectional view corresponding to the dashed-dotted line A1-A2 in Fig. 1A, and Fig. 11B is a schematic cross-sectional view corresponding to the dashed-dotted line B1-B2.

[0200] 11A shows cross sections of light-emitting elements 110R, 110G, and 110B. The light-emitting element 110R has a pixel electrode 111R, an EL layer 112R, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an EL layer 112G, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an EL layer 112B, and a common electrode 113.

[0201] The light-emitting element 110R has an EL layer 112R between the pixel electrode 111R and the common electrode 113. The light-emitting element 110G has an EL layer 112G between the pixel electrode 111G and the common electrode 113. The light-emitting element 110B has an EL layer 112B between the pixel electrode 111B and the common electrode 113.

[0202] Insulating layers 130 and 131 are provided so as to fill the gaps between the stacked pixel electrodes 111 and EL layers 112 and adjacent stacked pixel electrodes 111 and EL layers 112. The insulating layer 130 is provided so as to be in contact with the side surfaces of the pixel electrodes 111 and the EL layers 112 of the light-emitting elements 110. In addition, in a cross-sectional view, the insulating layer 131 is provided in contact with the insulating layer 130 so as to fill recesses in the insulating layer 130.

[0203] In FIG. 1A, the insulating layer 130 and the insulating layer 131 are arranged between the pixel electrodes 111 and / or the EL layers 112 between adjacent pixels so as to have a mesh-like (which can also be called a lattice-like or matrix-like) shape when viewed from above.

[0204] 11B, by providing insulating layers 130 and 131 between light-emitting elements of different colors, the EL layers 112R, 112G, and 112B can be prevented from contacting each other. This effectively prevents current from flowing through two adjacent EL layers, thereby preventing unintended light emission. This improves contrast and realizes a display device with high display quality.

[0205] Note that the insulating layers 130 and 131 may not be provided between adjacent pixels exhibiting the same color, and may be formed only between pixels exhibiting different colors. In this case, the insulating layers 130 and 131 may have a striped shape when viewed from above. By forming the insulating layers 130 and 131 in a striped shape, the space required to form the insulating layers 130 and 131 is eliminated compared to when the insulating layers 130 and 131 have a grid shape, thereby increasing the aperture ratio. When the insulating layers 130 and 131 are formed in a striped shape, adjacent EL layers of the same color may be processed into a strip shape so as to be continuous in the column direction.

[0206] The common electrode 113 is provided in contact with the top surface of the EL layer 112, the top surface of the insulating layer 130, and the top surface of the insulating layer 131. Between adjacent light-emitting elements, at the ends of the pixel electrode 111 and the EL layer 112, a step is formed between a region where the pixel electrode 111 and the EL layer 112 are provided and a region where the pixel electrode 111 and the EL layer 112 are not provided. In the display device of one embodiment of the present invention, the insulating layers 130 and 131 planarize the step, improving the coverage of the common electrode compared to when the common electrode 113 is provided in contact with the substrate 101 between adjacent light-emitting elements. This can suppress connection defects due to disconnection. Alternatively, the step can suppress an increase in electrical resistance due to a local thinning of the common electrode 113.

[0207] Furthermore, if an edge of the pixel electrode 111 is substantially aligned with an edge of the EL layer 112, the common electrode 113 and the pixel electrode 111 may be short-circuited when the common electrode 113 is formed on the EL layer 112. In one embodiment of the present invention, by providing the insulating layers 130 and 131 between the adjacent EL layers 112, unevenness on the formation surface of the common electrode 113 can be reduced, thereby improving coverage of the edge of the EL layer 112 with the common electrode 113 and realizing good conductivity of the common electrode 113. Furthermore, short-circuiting between the common electrode 113 and the pixel electrode 111 can be suppressed.

[0208] In order to improve the flatness of the surface on which the common electrode 113 is formed, it is preferable that the top surfaces of the insulating layer 130 and the insulating layer 131 are approximately aligned with the top surface of the EL layer 112. It is also preferable that the top surface of the insulating layer 131 has a flat shape. However, the top surfaces of the insulating layer 130, the insulating layer 131, and the EL layer 112 do not necessarily have to be aligned with each other.

[0209] The insulating layer 130 has a region in contact with the side surface of the EL layer 112 and functions as a protective insulating layer for the EL layer 112. By providing the insulating layer 130, it is possible to prevent oxygen, moisture, or their constituent elements from entering the inside from the side surface of the EL layer 112, thereby providing a highly reliable display device.

[0210] If the width of the insulating layer 130 in the region in contact with the side surface of the EL layer 112 in a cross-sectional view is large, the spacing between the EL layers 112 may become large, resulting in a low aperture ratio. Furthermore, if the width of the insulating layer 130 is small, the effect of suppressing the intrusion of oxygen, moisture, or their constituent elements into the interior of the EL layer 112 from the side surface may become small. The width of the insulating layer 130 in the region in contact with the side surface of the EL layer 112 is preferably 3 nm to 200 nm, more preferably 3 nm to 150 nm, even more preferably 5 nm to 150 nm, still more preferably 5 nm to 100 nm, even more preferably 10 nm to 100 nm, and still more preferably 10 nm to 50 nm. By setting the width of the insulating layer 130 within the above range, a display device having a high aperture ratio and high reliability can be obtained.

[0211] The insulating layer 130 can be an insulating layer containing an inorganic material. For example, the insulating layer 130 can be formed using a single layer or a stacked layer of aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride oxide, or the like.

[0212] In this specification, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0213] The insulating layer 130 can be formed by a sputtering method, a chemical vapor deposition (CVD) method, a molecular beam epitaxy (MBE) method, a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, etc. The insulating layer 130 can be preferably formed by the ALD method, which has good coverage.

[0214] The insulating layer 131 provided on the insulating layer 130 has the function of planarizing recesses formed in the insulating layer 130 between adjacent light-emitting elements. In other words, the presence of the insulating layer 131 has the effect of improving the planarity of the surface on which the common electrode 113 is formed. An insulating layer containing an organic material can be suitably used as the insulating layer 131. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene-based resin, phenolic resin, precursors of these resins, etc. can be used as the insulating layer 131.

[0215] The difference in height between the top surface of the insulating layer 131 and the top surface of the EL layer 112 is, for example, preferably 0.5 times or less the thickness of the insulating layer 131, and more preferably 0.3 times or less the thickness of the insulating layer 131. Alternatively, for example, the insulating layer 131 may be provided so that the top surface of the EL layer 112 is higher than the top surface of the insulating layer 131. Alternatively, for example, the insulating layer 131 may be provided so that the top surface of the insulating layer 131 is higher than the top surface of the light-emitting layer of the EL layer 112. Preferably, the thickness of the insulating layer 131 is, for example, 0.3 times or more, 0.5 times or more, or 0.7 times or more the thickness from the bottom surface of the pixel electrode 111 to the top surface of the EL layer 112.

[0216] Furthermore, a protective layer 121 is provided on the common electrode 113 to cover the light emitting elements 110R, 110G, and 110B.

[0217] [Configuration Example 2-2] Display device 100A shown in Figures 12A and 12B differs from display device 100 shown in Figures 11A and 11B mainly in having a common layer 114. Figure 12A is a schematic cross-sectional view corresponding to dashed dotted line A1-A2 in Figure 1A, and Figure 12B is a schematic cross-sectional view corresponding to dashed dotted line B1-B2.

[0218] 12A and 12B differs from the display device 100A shown in FIGS. 2A and 2B in that it has an insulating layer 130.

[0219] The common layer 114, like the common electrode 113, is provided across a plurality of light-emitting elements. The common layer 114 is provided to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B. The structure including the common layer 114 can simplify the manufacturing process and reduce manufacturing costs. The common layer 114 and the common electrode 113 can be formed successively without any process such as etching therebetween. Therefore, the interface between the common layer 114 and the common electrode can be made clean, and good characteristics can be obtained in the light-emitting element.

[0220] The common layer 114 preferably contacts one or more of the top surfaces of the EL layer 112R, the EL layer 112G, and the EL layer 112B.

[0221] [Configuration Example 3-2] Display device 100B shown in Fig. 20A differs from display device 100B shown in Fig. 10A mainly in that it has insulating layer 130. Display device 100C shown in Fig. 20B differs from display device 100C shown in Fig. 10B mainly in that it has insulating layer 130.

[0222] 20A , the light-emitting element 110R has an optical adjustment layer 115R between the pixel electrode 111R and the EL layer 112R. The light-emitting element 110G has an optical adjustment layer 115G between the pixel electrode 111G and the EL layer 112G. The light-emitting element 110B has an optical adjustment layer 115B between the pixel electrode 111B and the EL layer 112B.

[0223] The display device 100C shown in Figure 20B differs from the display device 100B shown in Figure 20A mainly in that it has a common layer 114 between the EL layer 112 and the common electrode 113, and the configuration of the light-emitting element is different due to the common layer 114.

[0224] As shown in Figures 20A and 20B, by having an optical adjustment layer 115 and filling the gaps between the light-emitting elements with insulating layers 130 and 131, a display device with high color purity and high reliability can be obtained.

[0225] In the display device of this embodiment mode described above, an EL layer is not formed using a metal mask, and therefore, a display device can be made larger, have higher resolution, or have higher definition.

[0226] Furthermore, since the display device of this embodiment has a configuration in which the gap between adjacent EL layers or between the pixel electrode and the EL layer is filled with an insulating layer having a stacked structure, the flatness of the surface on which the common electrode is formed can be improved, and therefore, the formation of a step or a local thin film region in the common electrode can be suppressed, thereby improving the reliability of the display device.

[0227] In particular, by using an insulating layer containing an organic material as one of the insulating layers having a laminated structure, the surface on which the common electrode or common layer is formed can be effectively flattened. Also, by providing an insulating layer containing an inorganic material as one of the insulating layers having a laminated structure in a manner in contact with the side surface of the EL layer, impurities can be prevented from being mixed into the EL layer, thereby improving the reliability of the display device.

[0228] By using the above-described structure and manufacturing method of a display device according to one embodiment of the present invention, a display device including a fine, high-luminance, and highly reliable organic EL element can be provided.

[0229] 11A and 11B will be described as an example. 13A to 14F are schematic cross-sectional views illustrating steps in a manufacturing method of a display device exemplified below.

[0230] [Preparation of Substrate 101] First, prepare the substrate 101. For the substrate 101, the description in the manufacturing method 1 can be referred to.

[0231] Subsequently, a conductive film 111 f that will become the pixel electrode 111 is formed on the substrate 101 .

[0232] [Formation of EL Film 112Rf] Subsequently, an EL film 112Rf, which will later become the EL layer 112R, is formed on the conductive film 111f. For the EL film 112Rf, the description in the above-mentioned manufacturing method 1 can be referred to.

[0233] [Formation of Sacrificial Film 144a] Subsequently, a sacrificial film 144a is formed to cover the EL film 112Rf. For the sacrificial film 144a, the description in the manufacturing method 1 above can be referred to.

[0234] [Formation of Protective Film 146a] Subsequently, the protective film 146a is formed on the sacrificial film 144a. For the protective film 146a, the description in the manufacturing method 1 can be referred to.

[0235] [Formation of Resist Mask 143a] Subsequently, a resist mask 143a is formed on the protective film 146a (FIG. 13A). The resist mask 143a can be formed as described in the manufacturing method 1.

[0236] [Etching of Protective Film 146a] Subsequently, a portion of the protective film 146a that is not covered by the resist mask 143a is removed by etching to form island-shaped or strip-shaped protective layers 147a.

[0237] When etching the protective film 146a, it is preferable to use etching conditions with a high selectivity so that the sacrificial film 144a is not removed by the etching. The protective film 146a can be etched by wet etching or dry etching, but using dry etching can prevent the pattern of the protective film 146a from shrinking.

[0238] [Removal of Resist Mask 143a] Subsequently, the resist mask 143a is removed.

[0239] The resist mask 143a can be removed by wet etching or dry etching. In particular, the resist mask 143a is preferably removed by dry etching (also called plasma ashing) using oxygen gas as an etching gas.

[0240] At this time, the removal of the resist mask 143a is performed in a state where the EL film 112Rf is covered with the sacrificial film 144a, so that the influence on the EL film 112Rf is suppressed. In particular, if the EL film 112Rf comes into contact with oxygen, it may have an adverse effect on the electrical characteristics, so this is suitable when performing etching using oxygen gas, such as plasma ashing.

[0241] [Etching of Sacrificial Film 144a] Subsequently, using the protective layer 147a as a mask, the part of the sacrificial film 144a that is not covered by the protective layer 147a is removed by etching to form island-shaped or strip-shaped sacrificial layers 145a.

[0242] The sacrificial film 144a can be etched by wet etching or dry etching, but dry etching is preferable because it can prevent the pattern from shrinking.

[0243] [Etching of EL Film 112Rf] Subsequently, a part of the EL film 112Rf that is not covered with the sacrificial layer 145a is removed by etching to form island-shaped or strip-shaped EL layers 112R (FIG. 13B).

[0244] For etching the EL film 112Rf, it is preferable to use dry etching using an etching gas that does not contain oxygen as a main component. This makes it possible to suppress the deterioration of the EL film 112Rf and realize a highly reliable display device. As an etching gas that does not contain oxygen as a main component, for example, CF ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ Examples of the etching gas include a noble gas such as He or a noble gas such as He. A mixed gas of the above gas and a dilution gas that does not contain oxygen can also be used as the etching gas. Here, the protective layer 147a may be removed during the etching of the EL film 112Rf.

[0245] [Formation of EL Layer 112G and EL Layer 112B] Subsequently, an EL film 112Gf that will become the EL layer 112G is formed on the sacrificial layer 145a and the exposed conductive film 111f. For the EL film 112Gf, the description of the EL film 112Rf can be referred to.

[0246] Next, a sacrificial film 144b is formed on the EL film 112Gf, and a protective film 146b is formed on the sacrificial film 144b. The description of the sacrificial film 144a can be referred to for the sacrificial film 144b. The description of the protective film 146a can be referred to for the protective film 146b.

[0247] Subsequently, a resist mask 143b is formed on the protective film 146b (FIG. 13C).

[0248] Subsequently, the protective film 146b is etched using the resist mask 143b to form a protective layer 147b, and then the resist mask 143b is removed.

[0249] Subsequently, the sacrificial film 144b and the EL film 112Gf are etched using the protective layer 147b as a mask to form the sacrificial layer 145b and the EL layer 112Gf (FIG. 13D).

[0250] Subsequently, an EL film 112Bf to be the EL layer 112B is formed on the sacrificial layer 145a, the sacrificial layer 145b, and the exposed conductive film 111f. For the EL film 112Bf, the description of the EL film 112Rf can be referred to.

[0251] Next, a sacrificial film 144c is formed on the EL film 112Bf, and a protective film 146c is formed on the sacrificial film 144c. The description of the sacrificial film 144a can be referred to for the sacrificial film 144c. The description of the protective film 146a can be referred to for the protective film 146c.

[0252] Subsequently, a resist mask 143c is formed on the protective film 146c (FIG. 13E).

[0253] Subsequently, the protective film 146c is etched using the resist mask 143c to form a protective layer 147c, and then the resist mask 143c is removed.

[0254] Subsequently, the sacrificial film 144c and the EL film 112Bf are etched using the protective layer 147c as a mask to form the sacrificial layer 145c and the EL layer 112Bf (FIG. 13F).

[0255] [Formation of pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B] Subsequently, portions of the conductive film 111f that are not covered by the EL layer 112R, the EL layer 112G, the EL layer 112B, the sacrificial layer 145a, the sacrificial layer 145b, the sacrificial layer 145c, the protective layer 147a, the protective layer 147b, and the protective layer 147c are etched to form the pixel electrode 111R, the pixel electrode 111G, and the pixel electrode 111B ( FIG. 14A ).

[0256] The conductive film 111f can be etched by wet etching or dry etching. Here, by using dry etching using an etching gas that does not contain oxygen as a main component as the etching condition for the conductive film 111f, damage to the EL layer 112 can be reduced.

[0257] [Formation of Insulating Layer 130] Next, an insulating film 130f that will become the insulating layer 130 is formed ( FIG. 14B ). The insulating film 130f is preferably a film containing an inorganic material. For example, a film containing aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride oxide, or the like can be used as a single layer or a stacked layer.

[0258] The insulating film 130f can be formed by sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), atomic layer deposition (ALD), etc. The insulating film 130f can be preferably formed by ALD, which has good coverage.

[0259] [Formation of Insulating Layer 131] Next, an insulating film 131f that will become the insulating layer 131 is formed ( FIG. 14C ). The insulating film 131f is provided so as to cover the protective layer 147, the sacrificial layer 145, the EL layer 112, and the pixel electrodes 111. The insulating film 131f is preferably a planarizing film.

[0260] The insulating film 131f is preferably an insulating film containing an organic material, and the organic material is preferably a resin.

[0261] Examples of materials that can be used for the insulating film 131f include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0262] Next, the insulating films 130f and 131f are etched to expose the upper surface of the protective layer 147 (FIG. 14D). As a result, the insulating layers 130 and 131 are formed to cover the side surfaces of the EL layers 112R, 112G, and 112B. The insulating films 130f and 131f are etched substantially uniformly over the upper surfaces of the insulating films 130f and 131f. This uniform etching and planarization is also referred to as etch-back.

[0263] The insulating films 130f and 131f can be etched by dry etching or wet etching. Alternatively, etching may be performed by ashing using oxygen plasma or the like. Note that ashing using oxygen plasma has advantages such as high controllability, good in-plane uniformity, and suitability for processing using large substrates, and is therefore suitable for removing parts of the insulating films 130f and 131f. Alternatively, chemical mechanical polishing (CMP) may be used to etch the insulating films 130f and 131f.

[0264] Note that when etching the insulating films 130f and 131f, it is preferable to suppress damage to the EL layer 112 due to etching. Therefore, for example, it is preferable to perform etching so as to reduce exposure of the side surfaces of the EL layer 112. Furthermore, by etching the insulating films 130f and 131f with the sacrificial layer 145 and / or the protective layer 147 provided on the EL layer 112, damage to the top surface of the EL layer 112 due to etching can be suppressed.

[0265] When the insulating layer 130 and the insulating layer 131 are formed, the height of the top surface of the insulating layer 130 and / or the height of the top surface of the insulating layer 131 can be adjusted by the etching amount. Here, it is preferable to adjust the etching amount so that the insulating layer 130 covers the side surfaces of the EL layer 112. In particular, it is preferable to adjust the etching amount so that the insulating layer 130 covers the side surfaces of the light-emitting layer included in the EL layer 112.

[0266] 14D , in this embodiment, etching is performed so that the top surfaces of the insulating layer 130 and the insulating layer 131 are substantially aligned with the top surface of the EL layer 112. Also shown is an example in which the insulating layer 130 and the insulating layer 131 are formed so that the top surface and side surface of the protective layer 147 and the side surface of the sacrificial layer 145 are exposed. By substantially aligning the top surfaces of the insulating layer 130 and the insulating layer 131 with the top surface of the EL layer, in the formation of the common electrode 113 shown in FIG. 14F (described later), unevenness on the surface on which the common electrode 113 is provided can be reduced, thereby improving coverage.

[0267] Note that the surface flatness of the insulating film 131f containing an organic material may change depending on the unevenness of the surface on which the insulating film 131f is formed and the density of the pattern formed on the surface on which the insulating film 131f is formed. Furthermore, the flatness of the insulating film 131f may change depending on the viscosity of the material used for the insulating film 131f. For example, the thickness of the insulating film 131f in a region that does not overlap with the EL layer 112 may be smaller than the thickness of the insulating film 131f in a region that overlaps with the EL layer 112. In such a case, for example, by etching back the insulating film 131f, the height of the top surface of the insulating layer 131 may become lower than the height of the top surface of the protective layer 147 or the height of the top surface of the sacrificial layer 145.

[0268] Furthermore, the insulating film 131f may have a shape having a concave curved surface (a recessed shape) or a shape having a convex curved surface (a bulging shape) in the region between the plurality of EL layers 112.

[0269] [Removal of Protective Layer and Sacrificial Layer] Next, the protective layer 147a, the protective layer 147b, the protective layer 147c, the sacrificial layer 145a, the sacrificial layer 145b, and the sacrificial layer 145c are removed to expose the upper surfaces of the EL layer 112R, the EL layer 112G, and the EL layer 112B (Figure 14E).

[0270] 14E shows an example in which the insulating layer 130 is provided so that the height of the top surface of the insulating layer 130 is approximately the same as the height of the top surface of the EL layer 112. In Fig. 14E, the top surface of the EL layer 112 is exposed, and the side surfaces of the EL layer 112 are covered with the insulating layer 130. Covering the side surfaces of the EL layer 112 with the insulating layer 130 prevents deterioration of the EL layer due to moisture and reduces damage to the EL layer when the protective layer 147 is etched.

[0271] The shape or height of the upper surface of the insulating layer 130 and / or the insulating layer 131 may change depending on the process of removing the protective layer and the sacrificial layer.

[0272] The protective layers 147a, 147b, and 147c can be removed by wet etching or dry etching.

[0273] The sacrificial layers 145a, 145b, and 145c can be removed by wet etching or dry etching. At this time, it is preferable to use a method that causes as little damage as possible to the EL layers 112R, 112G, and 112B. In particular, it is preferable to use a wet etching method. For example, it is preferable to use wet etching using a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture of these. Using these wet etching conditions can reduce damage to the insulating layer, for example.

[0274] 14C to 14E show an example in which the protective layer and the sacrificial layer are removed after etching back the insulating films 130f and 131f, but the embodiment of the present invention is not limited to this. For example, the insulating layers 130 and 131 may be formed by removing the sacrificial layer 145 and the protective layer 147, and the insulating films 130f and 131f in the regions overlapping the protective layer 147, by a lift-off method or the like.

[0275] In this manner, the EL layer 112R, the EL layer 112G, and the EL layer 112B can be separately produced.

[0276] It is known that separate EL layers for light-emitting elements of different colors are formed by vapor deposition using a shadow mask such as a metal mask. However, this method can result in deviations from the design in the shape and position of the island-shaped organic film 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 deposited film due to vapor scattering, making it difficult to achieve high resolution and a high aperture ratio. Furthermore, during vapor deposition, debris may be generated due to material adhering to the metal mask. This debris may cause pattern defects in the light-emitting element. Furthermore, the debris may cause short circuits. Furthermore, a process for cleaning the material adhering to the metal mask is required. Therefore, measures have been taken to artificially increase the resolution (also known as pixel density) by applying special pixel arrangements such as a pentile array.

[0277] In one embodiment of the present invention, an EL layer is processed into a fine pattern without using a shadow mask such as a metal mask. This makes it possible to realize a display device with high definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, because the EL layer can be individually fabricated, a display device with extremely vivid, high contrast, and high display quality can be realized.

[0278] In this embodiment, an example is shown in which a light-emitting element having any one of three different color EL layers is used as a light-emitting element arranged in a pixel, but the embodiment of the present invention is not limited to this, and a pixel may be formed by light-emitting elements that exhibit two different colors, or by light-emitting elements of three or more colors.

[0279] [Formation of Common Electrode 113] Subsequently, the common electrode 113 is formed to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B. The common electrode 113 can be formed by, for example, sputtering or vacuum deposition.

[0280] Through the above steps, the light emitting elements 110R, 110G, and 110B can be fabricated.

[0281] [Formation of Protective Layer 121] Next, the protective layer 121 is formed on the common electrode 113 ( FIG. 14F ). The inorganic insulating film used for the protective layer 121 is preferably formed by sputtering, PECVD, or ALD. The ALD method is particularly preferred because it has excellent step coverage and is less likely to produce defects such as pinholes. Furthermore, the inkjet method is preferably used to form the organic insulating film, because it allows for the formation of a uniform film in the desired area.

[0282] Through the above steps, the display device 100 shown in FIGS. 11A and 11B can be manufactured.

[0283] By using the above manufacturing method, process damage to the EL layers 112R, 112G, and 112B can be reduced, and therefore a display device with extremely high reliability can be realized.

[0284] [Formation of common layer 114] Before forming the common electrode 113, the common layer 114 is formed to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B, and then the common electrode 113 is formed, thereby making it possible to manufacture the display device 100A shown in Figures 12A and 12B.

[0285] In the manufacturing method of the display device described in this embodiment, a sacrificial layer is formed using a resist mask, and the EL layer and pixel electrode can be processed using the formed sacrificial layer. Therefore, a light-emitting element can be formed without using different resist masks for processing the pixel electrode and the EL layer. Therefore, a light-emitting element can be formed without providing a positional margin between the pixel electrode and the edge of the EL layer. By reducing the positional margin, the light-emitting region can be widened, thereby increasing the aperture ratio of the light-emitting element. Furthermore, by reducing the positional margin, the pixel size can be reduced, thereby enabling a display device with high resolution. Furthermore, by reducing the number of times a resist mask is used, the process can be simplified, leading to reduced costs and improved yields.

[0286] When EL layers of different colors are adjacent, it is difficult to achieve a spacing of less than 10 μm using a formation method using, for example, a metal mask. However, the above method can narrow the spacing to 3 μm or less, 2 μm or less, or even 1 μm or less. For example, by using 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 elements, 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%.

[0287] Furthermore, the pattern of the EL layer itself can be made much smaller than when a metal mask is used. Furthermore, for example, when a metal mask is used to separately form an EL layer, thickness variations occur between the center and edges of the pattern, resulting in a smaller effective area that can be used as the light-emitting region relative to the overall area of ​​the pattern. On the other hand, with the above-described fabrication method, a pattern is formed by processing a film deposited to a uniform thickness, making it possible to achieve a uniform thickness within the pattern, and even with a fine pattern, almost the entire area can be used as the light-emitting region. Therefore, the above-described fabrication method can achieve both high definition and a high aperture ratio.

[0288] In this way, according to the above-described manufacturing method, a display device integrating minute light-emitting elements can be realized, and therefore there is no need to apply a special pixel arrangement method such as a pen tile method to artificially increase the resolution. Therefore, it is possible to realize a display device with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, and with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, or even 3000 ppi or more, or even 5000 ppi or more.

[0289] 13A to 14F, a method is shown in which, after the EL layer 112 is formed, the conductive film 111f in a region not covered with the EL layer 112 is etched to form the pixel electrode 111 having edges that are substantially aligned with the edges of the EL layer 112. However, the embodiment of the present invention is not limited to this. With reference to FIGS. 15A to 15F, a second structural example and a manufacturing method thereof will be described in which the pixel electrodes 111R, 111G, and 111B are formed before the EL film 112Rf is formed.

[0290] First, as shown in Fig. 15A, pixel electrodes 111R, 111G, and 111B are formed. Then, as described with reference to Figs. 13A to 13F, EL layers 112, sacrificial layers 145, and protective layers 147 corresponding to the light-emitting elements 110 are formed using a resist mask or the like (Fig. 15B). Then, insulating films 130f and 131f are formed (Fig. 15C).

[0291] Next, as shown in FIG. 15D, the insulating films 130f and 131f are etched back, and then the sacrificial layer 145 and the protective layer 147 are removed (FIG. 15E), thereby obtaining the display device 100 shown in FIG. 15F.

[0292] 15F, the edge of the pixel electrode 111 is located outside the edge of the EL layer 112. In addition, on the upper surface of the pixel electrode 111, the edge and its vicinity are covered with an insulating layer 131.

[0293] 15A to 15F , by patterning the pixel electrodes 111R, 111G, and 111B in advance, damage to the EL layer 112 may be reduced compared to when a conductive film is patterned after the EL layer 112 is formed. Meanwhile, by configuring the edges of the EL layer 112 and the pixel electrode 111 to coincide with each other, as in Configuration Example 1, the width between adjacent light-emitting elements can be reduced, thereby improving the aperture ratio. Furthermore, the mask for forming the pixel electrode 111 can be reduced, thereby improving the yield of manufacturing the display device and reducing costs.

[0294] 16A shows another structural example of the display device 100 of this embodiment. In FIG. 16A, the upper surface of the insulating layer 131 has a region that is closer to the substrate 101 than the upper surface of the EL layer 112 (which can also be said to be lower than the upper surface of the EL layer 112).

[0295] 16A shows an example in which the upper surface of the insulating layer 131 formed by etch-back has a concave curved shape and its edge coincides with the upper surface of the insulating layer 130 and / or the EL layer 112 in a cross-sectional view, but the embodiment of the present invention is not limited to this. The upper surface of the insulating layer 131 may have a substantially flat shape and be located closer to the substrate 101 than the upper surface of the EL layer 112. Alternatively, the edge of the insulating layer 131 may contact the side surface of the insulating layer 130.

[0296] By providing the insulating layer 131 so that the upper surface of the insulating layer 131 is located closer to the substrate 101 than the upper surface of the EL layer 112, coverage of the upper surface of the EL layer 112 by the common electrode 113 may be improved.

[0297] 16B shows another structural example of the display device 100 of this embodiment. In FIG. 16B, the upper surface of the insulating layer 131 has a region that protrudes beyond the upper surface of the EL layer 112.

[0298] 16B shows an example in which the insulating layer 131 has a convex curved shape and its end coincides with the upper surface of the insulating layer 130 and / or the EL layer 112 in a cross-sectional view, but the embodiment of the present invention is not limited to this. The upper surface of the insulating layer 131 may have a substantially flat shape and may protrude from the upper surface of the EL layer 112.

[0299] By providing the insulating layer 131 so that the top surface of the insulating layer 131 is located closer to the substrate 101 than the top surface of the EL layer 112, the common electrode 113 has a region in contact with part of the side surface of the insulating layer 131. Note that, in the manufacturing process, removal of the protective layer 147 and the sacrificial layer 145 may etch part of the insulating layer 131, and the shape of the insulating layer 131 may change. For example, the thickness of the insulating layer 131 may become thinner. Furthermore, for example, corners formed by the top surface and side surface of the insulating layer 131 may become rounded. Rounding the corners formed by the top surface and side surface of the insulating layer 131 may improve the coverage of the common electrode 113.

[0300] As shown in configuration example 4, by making the upper surface of the insulating layer 131 protrude beyond the upper surface of the EL layer 112, the side surface of the EL layer 112 can also be protected by the insulating layer 131, and damage to the EL layer 112 during removal of the protective layer 147 can be reduced.

[0301] 17A shows another configuration example of the display device 100 of this embodiment. In FIG. 17A, the upper surface of the insulating layer 130 has a region that is closer to the substrate 101 than the upper surface of the EL layer 112 (which can also be said to be lower than the upper surface of the EL layer 112).

[0302] The insulating layer 131 is preferably in contact with at least a side surface of the light-emitting layer included in the EL layer 112. When the insulating layer 131 covers the side surface of the light-emitting layer, oxygen, moisture, or their constituent elements can be prevented from entering the interior from the side surface of the light-emitting layer, thereby providing a highly reliable display device.

[0303] 17B shows another configuration example of the display device 100 of this embodiment. In FIG. 17B, the upper surface of the insulating layer 130 has a region closer to the substrate 101 than the upper surface of the EL layer 112, and the upper surface of the insulating layer 131 has a region closer to the substrate 101 than the upper surface of the insulating layer 130.

[0304] 17B shows an example in which the upper surface of insulating layer 131 formed by etch-back has a concave curved shape, but the embodiment of the present invention is not limited to this. The upper surface of insulating layer 131 may have a substantially flat shape and be located closer to substrate 101 than the upper surface of insulating layer 130.

[0305] By configuring the upper surfaces of the insulating layers 130 and 131 to be positioned gradually closer to the substrate 101 than the upper surface of the EL layer 112, coverage of the common electrode 113 over the upper surface of the EL layer 112 may be improved.

[0306] 17C shows another configuration example of the display device 100 of this embodiment. In FIG. 17C , the upper surface of the insulating layer 130 has a region closer to the substrate 101 than the upper surface of the EL layer 112, and the upper surface of the insulating layer 131 has a region that protrudes beyond the upper surface of the insulating layer 130. In the protruding region, the side surface of the insulating layer 131 is in contact with the common electrode 113.

[0307] 17C shows an example in which the upper surface of insulating layer 131 has a convex curved shape, but the embodiment of the present invention is not limited to this. The upper surface of insulating layer 131 may have a substantially flat shape and may protrude further than the upper surface of insulating layer 130.

[0308] By making the top surface of the insulating layer 131 protrude beyond the top surface of the insulating layer 130, the side surfaces of the EL layer 112 in the areas not covered by the insulating layer 130 can be protected by the insulating layer 131, thereby reducing damage to the EL layer 112 when the protective layer 147 is removed.

[0309] 18A shows another configuration example of the display device 100 of this embodiment. In a cross-sectional view, the upper surfaces of the insulating layers 130 and 131 have regions that protrude beyond the upper surface of the EL layer 112. In the protruding regions, the side surfaces of the insulating layer 130 are in contact with the common electrode 113.

[0310] 18A , by making the upper surface of the insulating layer 130 protrude beyond the upper surface of the EL layer 112, the side surfaces of the EL layer 112 can be more reliably protected by the insulating layer 130, thereby improving the reliability of the display device. Furthermore, by making the upper surface of the insulating layer 131 protrude beyond the upper surface of the EL layer 112, like the upper surface of the insulating layer 130, the flatness of the formation surface of the common electrode 113 can be improved, thereby improving the coverage of the common electrode 113.

[0311] 18B shows another configuration example of the display device 100 of the present embodiment. The configuration example shown in Fig. 18B differs from the previously described configuration example 13 in that the upper surface of the insulating layer 131 has a region that is closer to the substrate 101 than the upper surface of the insulating layer 130, but is the same in other respects.

[0312] 18B shows an example in which the upper surface of insulating layer 131 formed by etch-back has a concave curved shape, but the embodiment of the present invention is not limited to this. The upper surface of insulating layer 131 may have a substantially flat shape and be located closer to substrate 101 than the upper surface of insulating layer 130.

[0313] 18C shows another configuration example of the display device 100 of the present embodiment. The configuration example shown in Fig. 18C differs from the previously described configuration example 13 in that the upper surface of the insulating layer 131 has a region that protrudes beyond the upper surface of the insulating layer 130, but is otherwise the same. In the region of the insulating layer 131 that protrudes beyond the upper surface of the insulating layer 130, the side surface of the insulating layer 131 is in contact with the common electrode 113.

[0314] 18C shows an example in which insulating layer 131 has a convex curved shape, but the embodiment of the present invention is not limited to this. The upper surface of insulating layer 131 may have a substantially flat shape and may protrude further than the upper surface of insulating layer 130.

[0315] By gradually protruding the upper surfaces of the insulating layers 130 and 131 in a direction away from the substrate 101 beyond the upper surface of the EL layer 112, coverage of the common electrode 113 over the upper surface of the EL layer 112 may be improved.

[0316] 19A to 19D show another structural example of this embodiment and a manufacturing method thereof. In Fig. 19, a groove is formed by etching a part of the substrate 101 when the pixel electrode 111 is formed.

[0317] 19A , pixel electrodes 111R, 111G, and 111B are formed. Depending on the etching conditions for the pixel electrodes 111, a part of the substrate 101 in an area not covered by the pixel electrodes 111 may be etched to form a groove 160. When a substrate on which a semiconductor circuit including semiconductor elements such as transistors is formed is used as the substrate 101, the groove 160 is formed at least in the uppermost insulating layer or conductive layer that will later come into contact with the insulating layer 130.

[0318] Thereafter, an insulating film 130f that covers the EL layer 112, the sacrificial layer 145, and the protective layer 147, and an insulating film 131f on the insulating film 130f are formed (FIG. 19B).

[0319] Next, as shown in FIG. 19C, the insulating films 130f and 131f are etched back, and then the sacrificial layer 145 and protective layer 147 are removed, and the common electrode 113 and protective layer 121 are formed to obtain the display device 100 shown in FIG. 19D.

[0320] 19A to 19D , the reliability of the insulating separation between the pixel electrodes 111R, 111G, and 111B is improved, and the common electrode 113 can be formed with good coverage by planarizing the irregularities caused by the groove portion 160 with the insulating layer 131. On the other hand, by using a configuration without the groove portion 160, as in Configuration Examples 1 to 10, the takt time in the pixel electrode 111 formation process can be shortened, and therefore the yield of manufacturing display devices can be improved.

[0321] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0322] Embodiment 2 In this embodiment, a structural example of a display device according to one embodiment of the present invention will be described.

[0323] 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, smartphones, wristwatch-type terminals, tablet terminals, personal digital assistants, and sound reproducing devices.

[0324] [Display Device 400A] FIG. 21 shows a perspective view of the display device 400A, and FIG. 22 shows a cross-sectional view of the display device 400A.

[0325] The display device 400A has a configuration in which a substrate 452 and a substrate 451 are bonded together. In Fig. 21, the substrate 452 is clearly indicated by a dashed line.

[0326] The display device 400A includes a display portion 462, a circuit 464, wiring 465, and the like. Fig. 21 shows an example in which an IC 473 and an FPC 472 are mounted on the display device 400A. Therefore, the configuration shown in Fig. 21 can also be considered as a display module including the display device 400A, an IC (integrated circuit), and an FPC.

[0327] The circuit 464 can be, for example, a scanning line driver circuit.

[0328] The wiring 465 has a function of supplying signals and power to the display portion 462 and the circuit 464. The signals and power are input to the wiring 465 from the outside via the FPC 472 or from the IC 473.

[0329] 21 shows an example in which an IC 473 is provided on a substrate 451 by a chip-on-glass (COG) method, a chip-on-film (COF) method, or the like. The IC 473 can be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 400A 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.

[0330] FIG. 22 shows an example of a cross section of the display device 400A, in which a part of a region including the FPC 472, a part of the circuit 464, a part of the display portion 462, and a part of a region including an end portion are cut away.

[0331] The display device 400A shown in Figure 22 has, between a substrate 451 and a substrate 452, a transistor 201, a transistor 205, a light-emitting element 430a that emits red light, a light-emitting element 430b that emits green light, and a light-emitting element 430c that emits blue light.

[0332] The light-emitting element described as an example in Embodiment 1 can be applied to the light-emitting element 430a, the light-emitting element 430b, and the light-emitting element 430c.

[0333] Here, when a pixel of a display device has three types of sub-pixels having light-emitting elements that emit different colors, the three sub-pixels include sub-pixels of three colors of R, G, and B, or sub-pixels of three colors of yellow (Y), cyan (C), and magenta (M), etc. When a pixel of a display device has four sub-pixels, the four sub-pixels include sub-pixels of four colors of R, G, B, and white (W), or sub-pixels of four colors of R, G, B, and Y, etc.

[0334] The protective layer 416 and the substrate 452 are bonded via an adhesive layer 442. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting element. In FIG. 22 , a space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 is filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure is applied. The adhesive layer 442 may be provided so as to overlap the light-emitting element. Furthermore, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 may be filled with a resin different from the adhesive layer 442.

[0335] The pixel electrode 411a, the pixel electrode 411b, and the pixel electrode 411c are each connected to a conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The pixel electrodes contain a material that reflects visible light, and the counter electrode contains a material that transmits visible light.

[0336] An insulating layer 421 is provided between the light-emitting elements 430a and 430b and between the light-emitting elements 430b and 430c. As the insulating layer 421, for example, the insulating layer 131 described in the above embodiment can be used.

[0337] Light emitted from the light-emitting element is emitted toward the substrate 452. The substrate 452 is preferably made of a material that is highly transparent to visible light.

[0338] The transistor 201 and the transistor 205 are both formed over a substrate 451. These transistors can be manufactured using the same material and through the same process.

[0339] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 451 in this order. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. A part of the insulating layer 213 functions as a gate insulating layer of each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0340] 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.

[0341] 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.

[0342] 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 400A. This makes it possible to prevent impurities from entering from the edge of the display device 400A through 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 400A, so that the organic insulating film is not exposed at the edge of the display device 400A.

[0343] An organic insulating film is suitable for the insulating layer 214 that functions as a planarizing layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0344] 22 , an opening is formed in the insulating layer 214. This makes it possible to prevent impurities from entering the display unit 462 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. This makes it possible to improve the reliability of the display device 400A.

[0345] 23 , after pixel electrodes 411a, 411b, and 411c are formed in openings provided in insulating layer 214, a layer 414 may be provided to fill recesses formed to cover the openings. By providing layer 414, unevenness on the surfaces on which optical adjustment layers 415a, 415b, 415c, EL layers 416a, 416b, and EL layers 416c are formed can be reduced, and coverage can be improved.

[0346] Layer 414 is preferably an insulating layer, or alternatively, layer 414 may be a conductive layer.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0351] 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).

[0352] 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.

[0353] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0354] 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.

[0355] For example, when describing a composition having an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when the atomic ratio of In is 4, the atomic ratio of Ga is 1 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when the atomic ratio of In is 5, the atomic ratio of Ga is more than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when the atomic ratio of In is 1, the atomic ratio of Ga is more than 0.1 and 2 or less, and the atomic ratio of Zn is more than 0.1 and 2 or less.

[0356] The transistors included in the circuit 464 may have the same structure as or different from the transistors included in the display portion 462. The transistors included in the circuit 464 may all have the same structure or may have two or more types of structures. Similarly, the transistors included in the display portion 462 may all have the same structure or may have two or more types of structures.

[0357] A connection portion 204 is provided in a region of the substrate 451 where the substrate 452 does not overlap. In the connection portion 204, a wiring 465 is electrically connected to an FPC 472 via a conductive layer 466 and a connection layer 242. The conductive layer 466 has an example of a stacked 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. The conductive layer 466 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 472 to be electrically connected via the connection layer 242.

[0358] It is preferable to provide a light-shielding layer 417 on the surface of substrate 452 facing substrate 451. In addition, various optical members can be arranged on the outside of substrate 452. 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 452.

[0359] By providing the protective layer 416 that covers the light-emitting element, impurities such as water can be prevented from entering the light-emitting element, and the reliability of the light-emitting element can be improved.

[0360] In a region 228 near the edge of the display device 400A, it is preferable that the insulating layer 215 and the protective layer 416 contact each other through the opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 416 contact each other. This makes it possible to prevent impurities from entering the display unit 462 from the outside via the organic insulating film. Therefore, it is possible to improve the reliability of the display device 400A.

[0361] The substrate 451 and the substrate 452 can each be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting element is extracted. Using a flexible material for the substrate 451 and the substrate 452 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used for the substrate 451 or the substrate 452.

[0362] The substrates 451 and 452 can be made of polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of the substrates 451 and 452 may be made of glass having a thickness sufficient to provide flexibility.

[0363] 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).

[0364] 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.

[0365] 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.

[0366] 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.

[0367] The adhesive layer can be made of various curable adhesives, such as photocurable adhesives (e.g., ultraviolet curable), reactive curable adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Adhesive sheets, etc., may also be used.

[0368] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0369] 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.

[0370] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials, can be used. Alternatively, nitrides of such metal materials (e.g., titanium nitride) can be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin them sufficiently to ensure light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These materials can also be used for conductive layers such as various wirings and electrodes constituting a display device, and for conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of light-emitting elements.

[0371] 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.

[0372] 24 shows an example of a cross section of the display device 400A-2, in which a portion of a region including the FPC 472, a portion of the circuit 464, a portion of the display portion 462, and a portion of a region including an end portion are cut away. The perspective view of the display device 400A-2 is the same as that of the display device 400A (FIG. 21). Note that descriptions of portions similar to those of the display device 400A may be omitted.

[0373] Note that the display device 400A-2 shown in Figure 24 differs from Figure 22 in that it has insulating layers 421a and 421b instead of insulating layer 421 as insulating layers provided between light-emitting elements 430a and 430b, and between light-emitting elements 430b and 430c.

[0374] The display device 400A-2 shown in Figure 24 has, between a substrate 451 and a substrate 452, a transistor 201, a transistor 205, a light-emitting element 430a that emits red light, a light-emitting element 430b that emits green light, and a light-emitting element 430c that emits blue light.

[0375] The light-emitting element described as an example in Embodiment 1 can be applied to the light-emitting element 430a, the light-emitting element 430b, and the light-emitting element 430c.

[0376] The protective layer 416 and the substrate 452 are bonded together via an adhesive layer 442 .

[0377] The pixel electrodes 411a, 411b, and 411c are each connected to a conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The pixel electrodes contain a material that reflects visible light, and the counter electrode contains a material that transmits visible light.

[0378] An insulating layer 421a is provided between the light-emitting element 430a and the light-emitting element 430b, and an insulating layer 421b is provided between the light-emitting element 430b and the light-emitting element 430c. For example, the insulating layer 130 shown in Fig. 11A, Fig. 12A, etc. in the previous embodiment and the insulating layer 131 provided to fill the recess of the insulating layer 130 can be used as the insulating layer 421a and the insulating layer 421b, respectively.

[0379] Light emitted from the light emitting element is emitted to the substrate 452 side.

[0380] The transistor 201 and the transistor 205 are both formed over a substrate 451 .

[0381] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over a substrate 451 in this order.

[0382] In region 228 shown in FIG. 24, an opening is formed in insulating layer 214 .

[0383] 25 , after pixel electrodes 411a, 411b, and 411c are formed in openings provided in an insulating layer 214, a layer 414 may be provided to fill recesses formed to cover the openings. By providing the layer 414, it is possible to reduce unevenness on the surfaces on which the optical adjustment layers 415a, 415b, and 415c and the EL layers 416a, 416b, and 416c are formed, thereby improving coverage. In FIG. 25 , descriptions of parts that are the same as those in the display device 400A may be omitted.

[0384] [Display Device 400B] Figure 26A shows a cross-sectional view of the display device 400B. The perspective view of the display device 400B is similar to that of the display device 400A (Figure 21). Figure 26A shows an example of a cross-section of the display device 400B, where a portion of a region including the FPC 472, a portion of the circuit 464, and a portion of the display unit 462 are cut away. Figure 26A shows an example of a cross-section of the display unit 462, where a region including the light-emitting element 430b that emits green light and the light-emitting element 430c that emits blue light is cut away. Note that descriptions of parts similar to those of the display device 400A may be omitted.

[0385] A display device 400B shown in FIG. 26A includes the transistor 202, the transistor 210, the light-emitting element 430b, the light-emitting element 430c, and the like between a substrate 453 and a substrate 454.

[0386] The substrate 454 and the protective layer 416 are bonded together via an adhesive layer 442. The adhesive layer 442 is provided to overlap the light-emitting element 430b and the light-emitting element 430c, respectively, and a solid sealing structure is applied to the display device 400B.

[0387] The substrate 453 and the insulating layer 212 are bonded together by an adhesive layer 455 .

[0388] The display device 400B is manufactured by first bonding a fabrication substrate provided with the insulating layer 212, the transistors, the light-emitting elements, and the like to a substrate 454 provided with a light-shielding layer 417 with an adhesive layer 442. The fabrication substrate is then peeled off, and a substrate 453 is attached to the exposed surface, thereby transferring each component formed on the fabrication substrate to the substrate 453. The substrate 453 and the substrate 454 are preferably flexible. This can increase the flexibility of the display device 400B.

[0389] The insulating layer 212 can be formed using the inorganic insulating film that can be used for the insulating layer 211, the insulating layer 213, and the insulating layer 215, respectively.

[0390] The pixel electrode is connected to a conductive layer 222b of the transistor 210 through an opening provided in the insulating layer 214. The conductive layer 222b is connected to a low-resistance region 231n through openings provided in the insulating layer 215 and the insulating layer 225. The transistor 210 has a function of controlling driving of a light-emitting element.

[0391] An insulating layer 421 is provided between the light emitting element 430b and the light emitting element 430c.

[0392] Light emitted from the light-emitting elements 430b and 430c is emitted toward the substrate 454. The substrate 454 is preferably made of a material that is highly transparent to visible light.

[0393] A connection portion 204 is provided in a region of the substrate 453 where the substrate 454 does not overlap. In the connection portion 204, a wiring 465 is electrically connected to an FPC 472 via a conductive layer 466 and a connection layer 242. The conductive layer 466 can be obtained by processing the same conductive film as the pixel electrode. This allows the connection portion 204 and the FPC 472 to be electrically connected via the connection layer 242.

[0394] The transistor 202 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 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 between the conductive layer 223 and the channel formation region 231i.

[0395] The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through an opening provided in the insulating layer 215. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0396] 26A shows an example in which the top surface and side surfaces of the semiconductor layer are covered with an insulating layer 225. 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.

[0397] 26B , the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the structure shown in FIG. 26B can be manufactured by processing the insulating layer 225 using the conductive layer 223 as a mask. In FIG. 26B , 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 each connected to the low-resistance region 231n through openings in the insulating layer 215. Furthermore, an insulating layer 218 may be provided to cover the transistor.

[0398] The transistor 210 and the transistor 202 may be replaced with a transistor 209 shown in FIG. 26B.

[0399] [Display device 400B-2] Fig. 27 shows a cross-sectional view of the display device 400B-2. The perspective view of the display device 400B-2 is similar to that of the display device 400A (Fig. 21). Fig. 27 shows an example of a cross-section of the display device 400B-2, where a part of a region including the FPC 472, a part of the circuit 464, and a part of the display portion 462 are cut away. Fig. 27 shows an example of a cross-section of the display portion 462, particularly, where a region including the light-emitting element 430b that emits green light and the light-emitting element 430c that emits blue light is cut away.

[0400] 22 in that the display device 400B-2 shown in Fig. 27 has insulating layers 421a and 421b instead of the insulating layer 421 as insulating layers provided between the light-emitting element 430b and the light-emitting element 430c. Descriptions of parts that are the same as those of the display device 400B may be omitted.

[0401] A display device 400B-2 illustrated in FIG. 27 includes the transistor 202, the transistor 210, the light-emitting element 430b, the light-emitting element 430c, and the like between a substrate 453 and a substrate 454.

[0402] The substrate 454 and the protective layer 416 are bonded together via an adhesive layer 442. The adhesive layer 442 is provided to overlap the light-emitting element 430b and the light-emitting element 430c, respectively, and a solid sealing structure is applied to the display device 400B.

[0403] The substrate 453 and the insulating layer 212 are bonded together by an adhesive layer 455 .

[0404] In a manufacturing method of the display device 400B-2, first, a manufacturing substrate provided with the insulating layer 212, each transistor, each light-emitting element, and the like is bonded to a substrate 454 provided with a light-shielding layer 417 with an adhesive layer 442. Then, the manufacturing substrate is peeled off, and a substrate 453 is attached to the exposed surface, thereby transferring each component formed on the manufacturing substrate to the substrate 453. The substrate 453 and the substrate 454 are preferably flexible. This can increase the flexibility of the display device 400B.

[0405] The pixel electrode is connected to a conductive layer 222b of the transistor 210 through an opening provided in the insulating layer 214. The conductive layer 222b is connected to a low-resistance region 231n through openings provided in the insulating layer 215 and the insulating layer 225. The transistor 210 has a function of controlling driving of a light-emitting element.

[0406] An insulating layer 421a and an insulating layer 421b are provided between the light emitting element 430b and the light emitting element 430c.

[0407] Light emitted from the light-emitting elements 430b and 430c is emitted toward the substrate 454. The substrate 454 is preferably made of a material that is highly transparent to visible light.

[0408] A connection portion 204 is provided in a region of the substrate 453 that does not overlap with the substrate 454. In the connection portion 204, a wiring 465 is electrically connected to an FPC 472 via a conductive layer 466 and a connection layer 242.

[0409] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0410] Embodiment Mode 3 In this embodiment mode, a structural example of a display device different from the above will be described.

[0411] 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.

[0412] 28A shows a perspective view of display module 280. Display module 280 has a display device 400C and an FPC 290. Note that the display device included in display module 280 is not limited to display device 400C, and may be display device 400D or display device 400E, which will be described later.

[0413] 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.

[0414] 28B 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.

[0415] The pixel portion 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of FIG. 28B . The pixel 284a includes light-emitting elements 430a, 430b, and 430c that emit light of different colors. The plurality of light-emitting elements are preferably arranged in a stripe array as shown in FIG. 28B . The stripe array allows pixel circuits containing light-emitting elements of one embodiment of the present invention to be arranged at high density, thereby providing a high-resolution display device. Furthermore, various arrangement methods, such as a delta array and a pentile array, can be applied.

[0416] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0417] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting elements included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting element. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitor for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0418] 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.

[0419] 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.

[0420] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are stacked below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 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.

[0421] 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.

[0422] [Display Device 400C] A display device 400C shown in FIG. 29 includes a substrate 301, light-emitting elements 430a, 430b, and 430c, a capacitor 240, and a transistor 310.

[0423] 28A and 28B. The laminated structure from the substrate 301 to the insulating layer 255 corresponds to the substrate in the first embodiment.

[0424] 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 and functions as an insulating layer.

[0425] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0426] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0427] 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.

[0428] 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.

[0429] An insulating layer 255 is provided to cover the capacitor 240, and light emitting elements 430a, 430b, 430c, etc. are provided on the insulating layer 255. A protective layer 416 is provided on the light emitting elements 430a, 430b, 430c, and a substrate 420 is bonded to the upper surface of the protective layer 416 by a resin layer 419. The substrate 420 corresponds to the substrate 292 in FIG. 28A .

[0430] The pixel electrode of the light-emitting element is electrically connected to one of the source or drain of the transistor 310 by a plug 256 embedded in the insulating layer 255, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261.

[0431] The insulating layers between the light-emitting elements 430a, 430b, and 430c and the light-emitting elements can have the structure described in Embodiment 1. Here, an example in which the structure shown in FIG. 1B is used is shown; however, applicable structures are not limited to this.

[0432] [Display device 400C-2] Display device 400C-2 shown in Fig. 30 differs from display device 400C shown in Fig. 29 in that a configuration having insulating layer 130 described in embodiment 1 is applied as an insulating layer between light-emitting elements. Fig. 30 shows an example in which the configuration shown in Fig. 10A is applied as light-emitting element 430a, light-emitting element 430b, light-emitting element 430c, and insulating layers between the light-emitting elements.

[0433] A display device 400C-2 shown in FIG. 30 includes a substrate 301, light-emitting elements 430a, 430b, and 430c, a capacitor 240, and a transistor 310.

[0434] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0435] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0436] 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.

[0437] 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.

[0438] An insulating layer 255 is provided to cover the capacitor 240, and light emitting elements 430a, 430b, 430c, etc. are provided on the insulating layer 255. A protective layer 416 is provided on the light emitting elements 430a, 430b, 430c, and a substrate 420 is bonded to the upper surface of the protective layer 416 by a resin layer 419. The substrate 420 corresponds to the substrate 292 in FIG. 28A .

[0439] The pixel electrode of the light-emitting element is electrically connected to one of the source or drain of the transistor 310 by a plug 256 embedded in the insulating layer 255, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261.

[0440] 31 is different from the display device 400C mainly in the configuration of the transistors. Note that descriptions of parts that are the same as those of the display device 400C may be omitted.

[0441] The transistor 320 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0442] 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 .

[0443] 28A and 28B . The stacked structure from the substrate 331 to the insulating layer 255 corresponds to the layer 401 including the transistor in Embodiment 2. The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0444] 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.

[0445] 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.

[0446] 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.

[0447] 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.

[0448] 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.

[0449] 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.

[0450] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0451] 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.

[0452] 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.

[0453] The configuration of the display device 400D from the insulating layer 254 to the substrate 420 is the same as that of the display device 400C.

[0454] [Display device 400D-2] Display device 400D-2 shown in Fig. 32 differs from display device 400C-2 mainly in the configuration of the transistors. Also, display device 400D-2 differs from display device 400D shown in Fig. 28 in that the configuration having insulating layer 130 described in embodiment 1 is applied. Note that descriptions of parts similar to display devices 400C, 400C-2, and 400D may be omitted.

[0455] The transistor 320 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0456] 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 .

[0457] An insulating layer 332 is provided on a substrate 331 .

[0458] 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.

[0459] 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 characteristics.

[0460] 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.

[0461] An insulating layer 328 is provided to cover the top surfaces and side surfaces of the pair of conductive layers 325 , the side surfaces of the semiconductor layer 321 , and the like, and an insulating layer 264 is provided over the insulating layer 328 .

[0462] 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.

[0463] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0464] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided so as to be embedded in the insulating layer 265 , the insulating layer 329 , and the insulating layer 264 .

[0465] The configuration of the display device 400D-2 from the insulating layer 254 to the substrate 420 is the same as that of the display device 400C-2.

[0466] 33 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 in which a metal oxide is included. Note that descriptions of parts similar to those of the display devices 400C and 400D may be omitted.

[0467] 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.

[0468] 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.

[0469] With this configuration, not only pixel circuits but also driver circuits and the like can be formed directly under the light-emitting elements, making it possible to miniaturize the display device compared to when driver circuits are provided around the periphery of the display area.

[0470] 34 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 semiconductor layer in which a channel is formed includes a metal oxide. The display device 400E-2 shown in Fig. 34 differs from the display device 400E shown in Fig. 33 in that the display device 400E-2 shown in Fig. 34 employs the structure including the insulating layer 130 described in Embodiment 1. Note that descriptions of parts similar to those of the display devices 400C, 400D, 400C-2, 400D-2, and 400E may be omitted.

[0471] 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.

[0472] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0473] Embodiment 4 In this embodiment, a light-emitting element (also referred to as a light-emitting device) that can be used for a display device that is one embodiment of the present invention will be described.

[0474] 35A , the light-emitting element has an EL layer 686 between a pair of electrodes (a lower electrode 672 and an upper electrode 688). The EL layer 686 can be composed of a plurality of layers such as a layer 4420, a light-emitting layer 4411, and a layer 4430. The layer 4420 can have, for example, a layer containing a substance with high electron-injection properties (electron-injection layer) and a layer containing a substance with high electron-transport properties (electron-transport layer). The light-emitting layer 4411 contains, for example, a light-emitting compound. The layer 4430 can have, for example, a layer containing a substance with high hole-injection properties (hole-injection layer) and a layer containing a substance with high hole-transport properties (hole-transport layer).

[0475] A structure having the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 35A is referred to as a single structure in this specification.

[0476] 35B shows a modified example of the EL layer 686 included in the light-emitting element shown in Fig. 35A. Specifically, the light-emitting element shown in Fig. 35B includes a layer 4430-1 on the lower electrode 672, a layer 4430-2 on the layer 4430-1, a light-emitting layer 4411 on the layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on the layer 4420-1, and an upper electrode 688 on the layer 4420-2. For example, when the lower electrode 672 is an anode and the upper electrode 688 is a cathode, the layer 4430-1 functions as a hole injection layer, the layer 4430-2 functions as a hole transport layer, the layer 4420-1 functions as an electron transport layer, and the layer 4420-2 functions as an electron injection layer. Alternatively, when the lower electrode 672 is a cathode and the upper electrode 688 is an anode, the layer 4430-1 functions as an electron injection layer, the layer 4430-2 functions as an electron transport layer, the layer 4420-1 functions as a hole transport layer, and the layer 4420-2 functions as a hole injection layer. By using such a layer structure, it is possible to efficiently inject carriers into the light-emitting layer 4411 and increase the efficiency of carrier recombination in the light-emitting layer 4411.

[0477] Note that a configuration in which a plurality of light-emitting layers (light-emitting layer 4411, light-emitting layer 4412, light-emitting layer 4413) are provided between layer 4420 and layer 4430 as shown in FIG. 35C is also a variation of the single structure.

[0478] 35D, a configuration in which a plurality of light-emitting units (EL layer 686a, EL layer 686b) are connected in series via an intermediate layer (charge generating layer) 4440 is referred to as a tandem structure in this specification. Note that although the configuration shown in FIG. 35D is referred to as a tandem structure in this specification and the like, it is not limited to this, and for example, the tandem structure may also be referred to as a stack structure. Note that by using a tandem structure, a light-emitting element capable of emitting light with high brightness can be obtained.

[0479] 35C and 35D, the layer 4420 and the layer 4430 may have a laminated structure consisting of two or more layers, as shown in FIG. 35B.

[0480] Furthermore, when the above-mentioned single structure and tandem structure are compared with the SBS structure described below, power consumption decreases in the order of the SBS structure, the tandem structure, and the single structure. If it is desired to keep power consumption low, the SBS structure is preferable. On the other hand, the single structure and tandem structure are preferable because their manufacturing processes are simpler than those of the SBS structure, allowing for lower manufacturing costs or higher manufacturing yields.

[0481] The light-emitting color of the light-emitting element can be red, green, blue, cyan, magenta, yellow, white, or the like, depending on the material constituting the EL layer 686. Furthermore, the color purity can be further improved by providing the light-emitting element with a microcavity structure.

[0482] A light-emitting element that emits white light preferably has a structure in which two or more types of light-emitting materials are contained in the light-emitting layer. To obtain white light emission, light-emitting materials may be selected such that the respective emissions of the two or more light-emitting materials have a complementary color relationship. 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 light-emitting element that emits white light as a whole can be obtained. The same applies to a light-emitting element having three or more light-emitting layers.

[0483] The light-emitting layer preferably contains two or more light-emitting materials that emit light of red (R), green (G), blue (B), yellow (Y), orange (O), etc. Alternatively, the light-emitting layer may contain light-emitting materials that emit light of purple, blue-purple, yellow-green, near-infrared, etc. Alternatively, the light-emitting layer preferably contains two or more light-emitting materials, and the light emitted by each of the light-emitting materials preferably contains spectral components of two or more colors of red, green, and blue.

[0484] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0485] Embodiment 5 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.

[0486] 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.

[0487] Furthermore, 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, an atomic layer deposition (ALD) method, or the like.

[0488] <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.

[0489] 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.

[0490] 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.

[0491] 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.

[0492] <<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.

[0493] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0494] [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.

[0495] 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.

[0496] 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.

[0497] 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.

[0498] 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).

[0499] 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 a dense arrangement of oxygen atoms in the a-b plane direction or the change in interatomic bond distance caused by metal atom substitution.

[0500] 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.

[0501] 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 or the generation of defects, 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.

[0502] [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.

[0503] [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.

[0504] <<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.

[0505] [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.

[0506] 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.

[0507] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In—Ga—Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In—Ga—Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0508] 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.

[0509] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0510] 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.

[0511] 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.

[0512] 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.

[0513] 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).

[0514] 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.

[0515] 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.

[0516] 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.

[0517] 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.

[0518] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0519] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0520] 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 or less, 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.

[0521] 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.

[0522] 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.

[0523] 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.

[0524] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0525] 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.

[0526] 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:

[0527] 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 or less, more preferably 1 × 10 １８ atoms / cm ３ or less, more preferably 5 × 10 １７ atoms / cm ３ Do the following:

[0528] 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.

[0529] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0530] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0531] Embodiment 6 In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS. 36A to 39F.

[0532] The electronic devices of this embodiment include the display device of one embodiment of the present invention. The display device of one embodiment of the present invention can easily achieve high definition, high resolution, and a large size. Therefore, the display device of one embodiment of the present invention can be used as a display portion of various electronic devices.

[0533] Furthermore, the display device of one embodiment of the present invention can be manufactured at low cost, which leads to a reduction in the manufacturing cost of electronic devices.

[0534] 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.

[0535] 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 information terminals (wearable devices) such as wristwatches and bracelets, as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays and AR glasses-type devices. Further, examples of wearable devices include SR devices and MR devices.

[0536] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280 × 720 pixels), FHD (1920 × 1080 pixels), WQHD (2560 × 1440 pixels), WQXGA (2560 × 1600 pixels), 4K2K (3840 × 2160 pixels), or 8K4K (7680 × 4320 pixels). A resolution of 4K2K, 8K4K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 300 ppi or higher, more preferably 500 ppi or higher, more preferably 1000 ppi or higher, more preferably 2000 ppi or higher, more preferably 3000 ppi or higher, more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using a display device with such high resolution or high definition, it is possible to further enhance the sense of presence and depth in electronic devices for personal use such as portable or home use.

[0537] The electronic device of this embodiment can be incorporated along the curved surface of the inner or outer wall of a house or building, or the interior or exterior of an automobile.

[0538] The electronic device of this embodiment may have an antenna. By receiving a signal through the antenna, images, information, and the like can be displayed on a display portion. In addition, when the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0539] 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).

[0540] 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.

[0541] The electronic device 6500 shown in FIG. 36A is a portable information terminal that can be used as a smartphone.

[0542] 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.

[0543] The display device of one embodiment of the present invention can be applied to the display portion 6502 .

[0544] FIG. 36B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0545] 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.

[0546] 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).

[0547] 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.

[0548] The flexible display (flexible display device) 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.

[0549] 37A 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.

[0550] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0551] 37A 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.

[0552] The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from a sender to a receiver) or two-way (between a sender and a receiver, or between receivers, etc.) information communication.

[0553] 37B 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, and an external connection port 7214. The housing 7211 includes a display portion 7000.

[0554] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0555] 37C and 37D show an example of digital signage.

[0556] 37C 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.

[0557] 37D 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.

[0558] 37C and 37D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0559] 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.

[0560] 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.

[0561] 37C and 37D , 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.

[0562] 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.

[0563] FIG. 38A is a diagram showing the appearance of the camera 8000 with the viewfinder 8100 attached.

[0564] The camera 8000 includes a housing 8001, a display unit 8002, operation buttons 8003, a shutter button 8004, and the like. A detachable lens 8006 is attached to the camera 8000. Note that the lens 8006 and the housing of the camera 8000 may be integrated together.

[0565] The camera 8000 can capture an image by pressing a shutter button 8004 or touching a display portion 8002 that functions as a touch panel.

[0566] The housing 8001 has a mount with electrodes, and can be connected to a finder 8100 as well as a strobe device and the like.

[0567] The finder 8100 includes a housing 8101, a display portion 8102, a button 8103, and the like.

[0568] The housing 8101 is attached to the camera 8000 by a mount that engages with the mount of the camera 8000. The viewfinder 8100 can display an image received from the camera 8000 on a display portion 8102.

[0569] The button 8103 has a function as a power button or the like.

[0570] The display device of one embodiment of the present invention can be applied to a display portion 8002 of a camera 8000 and a display portion 8102 of a finder 8100. Note that the camera 8000 may have a built-in finder.

[0571] FIG. 38B is a diagram showing the appearance of the head-mounted display 8200.

[0572] The head-mounted display 8200 includes a mounting portion 8201, a lens 8202, a main body 8203, a display portion 8204, and a cable 8205. The mounting portion 8201 has a built-in battery 8206.

[0573] A cable 8205 supplies power from a battery 8206 to the main body 8203. The main body 8203 includes a wireless receiver or the like and can display received video information on a display portion 8204. The main body 8203 also includes a camera and can use information on the movement of the user's eyeballs or eyelids as an input means.

[0574] The wearing unit 8201 may have a plurality of electrodes at positions that come into contact with the user, capable of detecting a current that flows in accordance with the movement of the user's eyeballs, and may have a function of recognizing the line of sight. The wearing unit 8201 may also have a function of monitoring the user's pulse based on the current that flows through the electrodes. The wearing unit 8201 may also have various sensors such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may have a function of displaying biometric information of the user on the display unit 8204 and a function of changing an image displayed on the display unit 8204 in accordance with the movement of the user's head.

[0575] The display device of one embodiment of the present invention can be applied to the display portion 8204 .

[0576] 38C to 38E are diagrams showing the appearance of a head mounted display 8300. The head mounted display 8300 includes a housing 8301, a display portion 8302, a band-shaped fixture 8304, and a pair of lenses 8305.

[0577] A user can view the display on the display portion 8302 through the lens 8305. Note that it is preferable to curve the display portion 8302 because the user can feel a high sense of presence. In addition, by viewing different images displayed in different regions of the display portion 8302 through the lens 8305, three-dimensional display using parallax can be performed. Note that the present invention is not limited to a configuration in which one display portion 8302 is provided, and two display portions 8302 may be provided, with one display portion provided for each eye of the user.

[0578] The display device of one embodiment of the present invention can be applied to the display portion 8302. The display device of one embodiment of the present invention can also achieve extremely high definition. For example, even when the display is enlarged and viewed using the lens 8305 as shown in FIG. 38E , the pixels are difficult for the user to view. That is, the display portion 8302 can be used to allow the user to view a highly realistic image.

[0579] 38F is a diagram showing the appearance of a goggle-type head-mounted display 8400. The head-mounted display 8400 includes a pair of housings 8401, an attachment portion 8402, and a cushioning member 8403. A display portion 8404 and a lens 8405 are provided in each of the pair of housings 8401. By displaying different images on the pair of display portions 8404, three-dimensional display using parallax can be performed.

[0580] A user can view the display portion 8404 through the lens 8405. The lens 8405 has a focus adjustment mechanism, and its position can be adjusted according to the user's eyesight. The display portion 8404 is preferably a square or a horizontally long rectangle. This can enhance the sense of realism.

[0581] The attachment portion 8402 preferably has plasticity and elasticity so that it can be adjusted according to the size of the user's face and does not slip off. Furthermore, a portion of the attachment portion 8402 preferably has a vibration mechanism that functions as a bone conduction earphone. This allows the user to enjoy video and audio simply by wearing the device, without the need for separate audio equipment such as earphones or speakers. The housing 8401 may also have a function for outputting audio data via wireless communication.

[0582] The mounting portion 8402 and the buffer member 8403 are portions that come into contact with the user's face (forehead, cheeks, etc.). The close contact of the buffer member 8403 with the user's face can prevent light leakage and enhance the sense of immersion. The buffer member 8403 is preferably made of a soft material so that it can be in close contact with the user's face when the user wears the head-mounted display 8400. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, using a sponge or the like with its surface covered with cloth, leather (natural leather or synthetic leather), or the like can prevent gaps from forming between the user's face and the buffer member 8403, thereby effectively preventing light leakage. Furthermore, using such a material is preferable because it feels pleasant to the touch and prevents the user from feeling cold when worn in cold seasons. It is preferable that the buffer member 8403 or the mounting portion 8402, or other components that come into contact with the user's skin, are removable for easy cleaning or replacement.

[0583] The electronic device shown in Figures 39A to 39F 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.

[0584] The electronic devices shown in Figures 39A to 39F 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.

[0585] The display device of one embodiment of the present invention can be applied to the display portion 9001 .

[0586] Details of the electronic device shown in Figures 39A to 39F will be described below.

[0587] FIG. 39A 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. 39A shows an example in which three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of the email or SNS message, the sender's name, the date and time, the remaining battery level, and the strength of antenna reception. Alternatively, an icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0588] 39B 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.

[0589] FIG. 39C 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 communication by intercommunicating 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. Charging may be performed by wireless power supply.

[0590] 39D to 39F are perspective views showing a foldable mobile information terminal 9201. Also, FIG. 39D is a perspective view of the mobile information terminal 9201 in an unfolded state, FIG. 39F is a perspective view of the mobile information terminal 9201 in a folded state, and FIG. 39E is a perspective view of a state in the process of changing from one of FIG. 39D and FIG. 39F to the other. The mobile information terminal 9201 has excellent portability in a folded state, and excellent display visibility due to a seamless, wide display area in an unfolded state. The display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

[0591] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0592] 100: display device, 100A: display device, 100B: display device, 100C: display device, 101: substrate, 110: light-emitting element, 110B: light-emitting element, 110G: light-emitting element, 110R: light-emitting element, 111: pixel electrode, 111B: pixel electrode, 111f: conductive film, 111G: pixel electrode, 111R: pixel electrode, 112: EL layer, 112B: EL layer, 112Bf: EL film, 112G: EL layer, 112Gf: EL film, 112R: EL layer, 112Rf: EL film, 113: common electrode, 114: common layer, 115: optical adjustment layer, 115B: optical adjustment layer, 115G: optical adjustment layer, 1 15R: optical adjustment layer, 121: protective layer, 130: insulating layer, 130f: insulating film, 131: insulating layer, 131f: insulating film, 143a: resist mask, 143b: resist mask, 143c: resist mask, 144a: sacrificial film, 144b: sacrificial film, 144c: sacrificial film, 145: sacrificial layer, 145a: sacrificial layer, 145b: sacrificial layer, 145c: sacrificial layer, 146a: protective film, 146b: protective film, 146c: protective film, 147: protective layer, 147a: protective layer, 147b: protective layer, 147c: protective layer, 201: transistor, 202: transistor, 204: connecting portion, 205: Transistor, 209: transistor, 210: transistor, 211: insulating layer, 212: 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, 228: region, 231: semiconductor layer, 231i: channel formation region, 231n: low resistance region, 240: capacitor, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 2 62: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274: plug, 274a: conductive layer, 274b: conductive layer, 280: display module, 281: display section, 282: circuit section, 283: pixel circuit section, 283a: pixel circuit, 284: pixel section, 284a: pixel, 285: terminal section, 286: wiring section, 290: FPC, 291: substrate, 292: substrate, 301: substrate, 310: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 321: semiconductor layer,323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 400A: display device, 400A-2: display device, 400B: display device, 400B-2: display device, 400C: display device, 400C-2: display device, 400D: display device, 400D-2: display device, 400E: display device, 400E-2: display device, 401: layer, 411a: pixel electrode, 411b: pixel electrode, 411c: pixel electrode, 414: layer, 415a: optical adjustment layer, 415b: optical adjustment layer, 41 5c: optical adjustment layer, 416: protective layer, 416a: EL layer, 416b: EL layer, 416c: EL layer, 417: light-shielding layer, 419: resin layer, 420: substrate, 421: insulating layer, 421a: insulating layer, 421b: insulating layer, 430a: light-emitting element, 430b: light-emitting element, 430c: light-emitting element, 442: adhesive layer, 443: space, 451: substrate, 452: substrate, 453: substrate, 454: substrate, 455: adhesive layer, 462: display section, 464: circuit, 465: wiring, 466: conductive layer, 472: FPC, 473: IC, 672: electrode, 686: EL layer, 686a: EL layer, 686b : EL layer, 688: electrode, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4420-1: layer, 4420-2: layer, 4430: layer, 4430-1: layer, 4430-2: layer, 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 operation 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 device, 7400: Digital signage, 7401: Pillar, 7411: Information terminal device, 8000: Camera, 8001: Housing, 8002: Display unit, 8003: Operation buttons,8004: shutter button, 8006: lens, 8100: viewfinder, 8101: housing, 8102: display unit, 8103: button, 8200: head-mounted display, 8201: attachment unit, 8202: lens, 8203: main body, 8204: display unit, 8205: cable, 8206: battery, 8300: head-mounted display, 8301: housing, 8302: display unit, 8304: fixture, 8305: lens, 8400: head-mounted display, 84 01: Housing, 8402: Mounting portion, 8403: Cushioning member, 8404: Display portion, 8405: Lens, 9000: Housing, 9001: Display portion, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Portable information terminal, 9102: Portable information terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

1. A first step of forming a first EL film on a first pixel electrode and on a second pixel electrode; a second step of forming a first sacrificial film on the first EL film; a third step of forming a first protective film on the first sacrificial film; a fourth step of forming a first resist mask on the first protective film in a region overlapping the first pixel electrode; a fifth step of etching the first protective film using the first resist mask to expose the first sacrificial film and forming a first protective layer on the first sacrificial film; a sixth step of removing the first resist mask; a seventh step of etching the first sacrificial film using the first protective layer as a mask to expose the first EL film and forming a first sacrificial layer on the first EL film; an eighth step of etching the first EL film using the first protective layer as a mask to expose the second pixel electrode and forming a first EL layer on the first pixel electrode; a ninth step of depositing a second EL film on the first protective layer and on the second pixel electrode; a tenth step of forming a second sacrificial film on the second EL film; an eleventh step of forming a second protective film on the second sacrificial film; a twelfth step of forming a second resist mask on the second protective film in a region overlapping the second pixel electrode; a thirteenth step of etching the second protective film using the second resist mask to expose the second sacrificial film and forming a second protective layer on the second sacrificial film; a fourteenth step of removing the second resist mask; a fifteenth step of etching the second sacrificial film using the second protective layer as a mask to expose the second EL film, and forming a second sacrificial layer on the second EL film; a sixteenth step of etching the second EL film using the second protective layer as a mask to expose the first protective layer and form a second EL layer on the second pixel electrode; a seventeenth step of forming a first insulating film on the first protective layer, on a side surface of the first protective layer, on a side surface of the first sacrificial layer, on a side surface of the first EL layer, on an upper surface end of the first pixel electrode, on a side surface of the first pixel electrode, between the first pixel electrode and the second pixel electrode, on the second protective layer, on a side surface of the second protective layer, on a side surface of the second sacrificial layer, on a side surface of the second EL layer, on an upper surface end of the second pixel electrode, and on a side surface of the second pixel electrode; an eighteenth step of forming a second insulating film on the first insulating film; a nineteenth step of etching the first insulating film and the second insulating film to expose the first protective layer and the second protective layer, and forming a first insulating layer and a second insulating layer on the first insulating layer on a side surface of the first pixel electrode, a side surface of the first EL layer, between the first pixel electrode and the second pixel electrode, a side surface of the second pixel electrode, and a side surface of the second EL layer; a twentieth step of etching the first protective layer, the first sacrificial layer, the second protective layer, and the second sacrificial layer to expose the first EL layer and the second EL layer; a 21st step of forming a common electrode on the first EL layer, on the first insulating layer, on the second insulating layer, and on the second EL layer; and a twenty-second step of forming a third protective layer on the common electrode.

2. In claim 1, The method for manufacturing a display device, wherein the first sacrificial film and the second sacrificial film include a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic insulating film.

3. In claim 1 or 2, the etching of the first sacrificial film and the second sacrificial film is performed by dry etching; The method for manufacturing a display device, wherein the etching of the first EL film and the second EL film is performed by dry etching.