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

Abstract

A display device with high resolution is provided. A display device with high display quality is provided. The display device comprises a transistor, a light-emitting diode, a first conductive layer positioned above the transistor and electrically connected to the transistor, a second conductive layer positioned above the first conductive layer and electrically connected to the light-emitting diode, a first insulating layer positioned above the transistor, and a second insulating layer positioned above the first insulating layer. The upper surface of the first conductive layer is approximately the same height as the upper surface of the first insulating layer, and the lower surface of the second conductive layer is approximately the same height as the lower surface of the second insulating layer. The first insulating layer and the second insulating layer are bonded to each other, and the first conductive layer and the second conductive layer are bonded to each other.

Description

Technology Field

[0001] One embodiment of the present invention relates to a display device, a display module, an electronic device, and a method for manufacturing the same.

[0002] Furthermore, 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 include semiconductor devices, display devices, light-emitting devices, capacitor devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), a method of driving any of these, and a method of manufacturing any of these. Background Technology

[0003] In recent years, display devices including micro light-emitting diodes (micro LEDs) as display devices (also called display elements) have been proposed (e.g., Patent Document 1). Display devices including micro LEDs as display devices have advantages such as high brightness, high contrast, and long lifespan, and are being actively developed as next-generation display devices. Prior art literature

[0004] U.S. Patent Application Publication US2014 / 0367705 The problem to be solved

[0005] As display devices, including Micro LEDs, it is necessary to reduce manufacturing costs because mounting LED chips takes a very long time. For example, in the pick-and-place method, red (R), green (G), and blue (B) LEDs are formed on separate wafers, and then the LEDs are cut out one by one and mounted on a circuit board. Therefore, as the number of pixels in the display device increases, the number of mounted LEDs also increases, leading to longer mounting times. Furthermore, as the resolution of the display device increases, mounting LEDs becomes more difficult.

[0006] An objective of one embodiment of the present invention is to provide a display device with high resolution. An objective of one embodiment of the present invention is to provide a display device with high resolution. An objective of one embodiment of the present invention is to provide a display device with high display quality. An objective of one embodiment of the present invention is to provide a display device with low power consumption. An objective of one embodiment of the present invention is to provide a display device with high reliability.

[0007] An objective of one embodiment of the present invention is to reduce the manufacturing cost of a display device including a micro LED as a display device. An objective of one embodiment of the present invention is to manufacture a display device including a micro LED as a display device with a high yield.

[0008] Furthermore, the description of these problems does not prevent the existence of other problems. One embodiment of the present invention is not required to achieve all of these problems. Other problems can be derived from the description of the specification, drawings, and claims. means of solving the problem

[0009] A display device of one embodiment of the present invention comprises a transistor, a light-emitting diode, a first conductive layer, a second conductive layer, a first insulating layer, and a second insulating layer. The transistor is electrically connected to the first conductive layer. The light-emitting diode is electrically connected to the second conductive layer. The first conductive layer is located over the transistor. The first insulating layer is located over the transistor. The second conductive layer is located over the first conductive layer. The second insulating layer is located over the first insulating layer. The light-emitting diode is located over the second insulating layer. The surface of the first conductive layer on the side of the second conductive layer is approximately the same height as the surface of the first insulating layer on the side of the second insulating layer. The surface of the second conductive layer on the side of the first conductive layer is approximately the same height as the surface of the second insulating layer on the side of the first insulating layer. The first insulating layer and the second insulating layer are directly bonded to each other. The first conductive layer and the second conductive layer are directly bonded to each other.

[0010] A display device of one embodiment of the present invention preferably further comprises a third insulating layer and a fourth insulating layer. The third insulating layer is preferably located between a transistor and a first insulating layer. The fourth insulating layer is preferably located between a light-emitting diode and a second insulating layer. The first insulating layer and the second insulating layer each preferably comprise a silicon oxide film. The third insulating layer and the fourth insulating layer each preferably comprise at least one of an aluminum oxide film, a hafnium oxide film, and a silicon nitride film.

[0011] It is preferable that the angle between the transistor-side surface of the first conductive layer and the side surface of the first conductive layer be greater than 0° and less than 90°, or greater than 0° and less than 90°. It is preferable that the angle between the transistor-side surface of the second conductive layer and the side surface of the second conductive layer be greater than 90° and less than 180°, or greater than 90° and less than 180°. In addition, according to a cross-sectional observation of a display device of one embodiment of the present invention, since the two conductive layers have different tapered shapes, the boundary between these two conductive layers can be estimated as the interface of adhesion.

[0012] A display device of one embodiment of the present invention preferably further comprises a fifth insulating layer. A transistor preferably comprises a metal oxide layer and a gate electrode. The metal oxide layer preferably comprises a channel forming region. The upper surface of the gate electrode preferably has a height approximately equal to that of the upper surface of the fifth insulating layer.

[0013] In one embodiment of the present invention, when a display device comprises a fifth insulating layer, the transistor preferably comprises a metal oxide layer, a gate insulating layer, a gate electrode, a third conductive layer, and a fourth conductive layer. The metal oxide layer preferably comprises a channel forming region. The metal oxide layer preferably comprises a first region overlapping with the third conductive layer, a second region overlapping with the fourth conductive layer, and a third region between the first region and the second region. The third conductive layer and the fourth conductive layer preferably are located apart from each other on the metal oxide layer. The fifth insulating layer preferably is located on the third conductive layer and the fourth conductive layer. The fifth insulating layer preferably comprises an opening overlapping with the third region. The gate insulating layer preferably is located inside the opening and overlaps with the side surface of the fifth insulating layer and the upper surface of the third region. The gate electrode preferably is located inside the opening and overlaps with the side surface of the fifth insulating layer and the upper surface of the third region through the gate insulating layer.

[0014] A display device of one embodiment of the present invention preferably further includes a driving circuit. The driving circuit preferably includes a circuit transistor. The circuit transistor preferably includes a channel forming region on a semiconductor substrate. The transistor, the light-emitting diode, the first conductive layer, the second conductive layer, the first insulating layer, and the second insulating layer preferably are located on the semiconductor substrate.

[0015] A display device of one embodiment of the present invention comprises a first transistor, a second transistor, a light-emitting diode, a first conductive layer, a second conductive layer, a first insulating layer, and a second insulating layer. The first transistor includes a channel forming region in a semiconductor substrate. The second transistor includes a metal oxide layer. The metal oxide layer includes a channel forming region. The second transistor is electrically connected to the first conductive layer. The light-emitting diode is electrically connected to the second conductive layer. The second transistor is located on the first transistor. The first conductive layer is located on the second transistor. The first insulating layer is located on the second transistor. The second conductive layer is located on the first conductive layer. The second insulating layer is located on the first insulating layer. The light-emitting diode is located on the second insulating layer. The surface of the first conductive layer on the side of the second conductive layer is approximately the same height as the surface of the first insulating layer on the side of the second insulating layer. The surface of the second conductive layer on the side of the first conductive layer is approximately the same height as the surface of the second insulating layer on the side of the first insulating layer. The first insulating layer and the second insulating layer are directly bonded to each other. The first conductive layer and the second conductive layer are directly bonded to each other.

[0016] It is preferable that the first conductive layer and the second conductive layer contain the same metal. It is preferable that the metal is gold, aluminum, tungsten, or copper.

[0017] It is preferable that the light-emitting diode be a micro light-emitting diode. It is also preferable that the light-emitting diode include a compound containing Group 13 and Group 15 elements. It is also preferable that the light-emitting diode include gallium nitride.

[0018] A display device of one embodiment of the present invention may include a first light-emitting diode and a second light-emitting diode that emit light of different colors. In this case, the transistor electrically connected to the first light-emitting diode and the transistor electrically connected to the second light-emitting diode may have different channel lengths and / or channel widths.

[0019] Alternatively, a display device of one form of the present invention may include a plurality of light-emitting diodes that emit light of the same color to each pixel of color.

[0020] A display device of one embodiment of the present invention preferably further comprises a functional layer. The functional layer preferably is positioned above a light-emitting diode. Light emitted from the light-emitting diode is preferably extracted to the outside of the display device through the functional layer. The functional layer preferably comprises one or both of a coloring layer and a color conversion layer. The color conversion layer preferably comprises quantum dots.

[0021] One embodiment of the present invention is a display module including a display device of any of the above structures. The display module may be provided with a connector such as a flexible printed circuit board (hereinafter referred to as FPC) or a TCP (tape carrier package). In addition, an integrated circuit (IC) may be mounted on the display module using a COG (chip on glass) method or a COF (chip on film) method.

[0022] One embodiment of the present invention is an electronic device comprising at least one of the display module, an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

[0023] One embodiment of the present invention is an electronic device comprising the display device, optical member, frame, and housing. The housing includes a touch sensor.

[0024] One embodiment of the present invention is a method for manufacturing a display device, comprising: forming a plurality of transistors as a matrix on a first substrate; forming a plurality of first conductive layers on the plurality of transistors, each electrically connected to at least one of the plurality of transistors; forming a plurality of light-emitting diodes as a matrix on a second substrate; forming a plurality of second conductive layers on the plurality of light-emitting diodes, each electrically connected to at least one of the plurality of light-emitting diodes; and bonding the first substrate and the second substrate by directly bonding each of the plurality of first conductive layers to at least one of the plurality of second conductive layers so that each of the plurality of transistors is electrically connected to at least one of the plurality of light-emitting diodes. In the step of forming the plurality of transistors, it is preferable to perform a planarization treatment at least once.

[0025] In a method for manufacturing a display device of one embodiment of the present invention, at least one of a coloring layer, a color conversion layer, and a touch sensor may be formed on a third substrate, the first substrate and the second substrate may be bonded together, the second substrate may be peeled off, and the third substrate may be bonded to the surface exposed by peeling off the second substrate.

[0026] Alternatively, in a method for manufacturing a display device of one embodiment of the present invention, at least one of a coloring layer, a color conversion layer, and a touch sensor may be formed on a third substrate, and after bonding the first substrate and the second substrate together, the second substrate may be polished to reduce the thickness of the second substrate, and the third substrate may be bonded to the polished surface of the second substrate.

[0027] One embodiment of the present invention is a method for manufacturing a display device, comprising the steps of: forming a plurality of first transistors, each including a channel forming region, on a first substrate; forming a plurality of second transistors as a matrix on the plurality of first transistors; forming a plurality of first conductive layers on the plurality of second transistors, each electrically connected to at least one of the plurality of second transistors; forming a plurality of light-emitting diodes as a matrix on a second substrate; forming a plurality of second conductive layers on the plurality of light-emitting diodes, each electrically connected to at least one of the plurality of light-emitting diodes; bonding the first substrate and the second substrate by directly bonding each of the plurality of first conductive layers to at least one of the plurality of second conductive layers so that each of the plurality of second transistors is electrically connected to at least one of the plurality of light-emitting diodes; subsequently, peeling off the second substrate; and forming at least one of a coloring layer, a color conversion layer, and a light-blocking layer on the surface exposed by peeling off the second substrate. In the step of forming the plurality of second transistors, it is preferable to perform a planarization treatment at least once.

[0028] It is preferable that at least one of the plurality of light-emitting diodes is a micro light-emitting diode. It is preferable that at least one of the plurality of transistors includes a metal oxide in the channel-forming region. Effects of the invention

[0029] According to one embodiment of the present invention, a display device with high resolution can be provided. According to one embodiment of the present invention, a display device with high resolution can be provided. According to one embodiment of the present invention, a display device with high display quality can be provided. According to one embodiment of the present invention, a display device with low power consumption can be provided. According to one embodiment of the present invention, a display device with high reliability can be provided.

[0030] According to one embodiment of the present invention, the manufacturing cost of a display device including a micro LED as a display device can be reduced. According to one embodiment of the present invention, a display device including a micro LED as a display device can be manufactured with a high yield.

[0031] Furthermore, the description of these effects does not interfere with the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Other effects may be derived from the descriptions in the specification, drawings, and claims. Brief explanation of the drawing

[0032] Figure 1 is a cross-sectional view showing an example of a display device. Figures 2 (A) to (C) are cross-sectional views showing an example of a method for manufacturing a display device. Figure 3 is a cross-sectional view showing an example of a display device. Figure 4 is a cross-sectional view showing an example of a display device. Figures 5 (A) and (B) are cross-sectional views showing examples of display devices, respectively. Figures 6 (A) and (B) are cross-sectional views showing an example of a method for manufacturing a display device. FIG. 7 is a cross-sectional view showing an example of a display device. FIG. 8 is a cross-sectional view showing an example of a display device. FIG. 9 is a cross-sectional view showing an example of a display device. Figures 10 (A) and (B) are cross-sectional views showing an example of a method for manufacturing a display device. FIG. 11 is a cross-sectional view showing an example of a method for manufacturing a display device. FIG. 12 is a cross-sectional view showing an example of a method for manufacturing a display device. FIG. 13 is a cross-sectional view showing an example of a method for manufacturing a display device. Figures 14 (A) to (D) are top and cross-sectional views showing an example of a transistor. Figure 15 is a circuit diagram showing an example of a pixel circuit. Figures 16 (A) and (B) show examples of electronic devices. Figures 17 (A) and (B) show examples of electronic devices. Figures 18 (A) and (B) show examples of electronic devices. Figures 19 (A) and (B) show examples of electronic devices. Figures 20 (A) to (D) each show an example of an electronic device. Figures 21 (A) to (F) each show an example of an electronic device. Specific details for implementing the invention

[0033] The embodiments will be described in detail with reference to the drawings. Furthermore, the present invention is not limited to the description below, and it is readily understood by those skilled in the art that the form and details of the present invention can be varied without departing from the spirit and scope of the invention. Accordingly, the present invention should not be interpreted as being limited to the descriptions of the embodiments and examples below.

[0034] In addition, in the structure of the present invention described below, the same parts or parts having similar functions are indicated by the same reference numerals in different drawings, and their description is not repeated. Parts having similar functions may use the same hatching pattern, and in some cases, those parts may not be indicated by a specific reference numeral.

[0035] The actual location, size, or range of each component shown in the drawings may not be indicated to facilitate understanding. Therefore, the disclosed invention is not necessarily limited to the location, size, or range disclosed in the drawings.

[0036] In addition, the terms "film" and "layer" may be interchanged depending on the case or situation. For example, the term "conductive layer" can be substituted with the term "conductive film." As another example, the term "insulating film" can be substituted with the term "insulating layer."

[0037] (Embodiment 1)

[0038] In this embodiment, a display device of one form of the present invention will be described with reference to FIGS. 1, FIGS. 2 (A) and (B), FIGS. 3, FIGS. 4, FIGS. 5 (A) and (B), FIGS. 6 (A) and (B), and FIGS. 7.

[0039] The display device of the present embodiment includes a plurality of light-emitting diodes that are display devices and a plurality of transistors that drive the display devices. The plurality of light-emitting diodes are arranged in a matrix on a substrate having transparency to visible light. Each of the plurality of transistors is electrically connected to at least one of the plurality of light-emitting diodes. The plurality of light-emitting diodes are located on the substrate side rather than the plurality of transistors. The plurality of light-emitting diodes emit light toward the substrate side.

[0040] The display device of the present embodiment is formed by bonding a plurality of transistors formed on a substrate and a plurality of light-emitting diodes formed on another substrate.

[0041] In the method for manufacturing a display device according to the present embodiment, since a plurality of light-emitting diodes and a plurality of transistors are bonded together at once, even when manufacturing a display device with a large number of pixels or high precision, the manufacturing time of the display device can be shortened and the difficulty of manufacturing can be lowered compared to the case of mounting light-emitting diodes one by one on a circuit board.

[0042] A method for manufacturing a display device of one embodiment of the present invention first forms a plurality of transistors as a matrix on a first substrate, and forms a first insulating layer and a plurality of first conductive layers on the plurality of transistors. Each of the plurality of first conductive layers is electrically connected to at least one of the plurality of transistors. Here, the first insulating layer and the first conductive layer are formed such that the upper surface of the first insulating layer and the upper surface of the first conductive layer are of the same height. A plurality of light-emitting diodes are formed as a matrix on a second substrate, and a second insulating layer and a plurality of second conductive layers are formed on the plurality of light-emitting diodes. Each of the plurality of second conductive layers is electrically connected to at least one of the plurality of light-emitting diodes. Here, the second insulating layer and the second conductive layer are formed such that the upper surface of the second insulating layer and the upper surface of the second conductive layer are of the same height.

[0043] A first substrate and a second substrate are bonded together so that each of a plurality of transistors is electrically connected to at least one of a plurality of light-emitting diodes. By bonding the first substrate and the second substrate, a plurality of light-emitting diodes and a plurality of transistors can be bonded together at once. Specifically, each of a plurality of first conductive layers is directly bonded to at least one of a plurality of second conductive layers. By doing so, the transistor can be electrically connected to the light-emitting diode through the first conductive layer and the second conductive layer. It is preferable that the first conductive layer and the second conductive layer contain the same metal element as their main components, and it is more preferable that the first conductive layer and the second conductive layer are formed using the same material. This increases the bonding strength between the first conductive layer and the second conductive layer. A first insulating layer is directly bonded to the second insulating layer. It is preferable that the first insulating layer and the second insulating layer are formed using the same material, and in particular, it is preferable to use a silicon oxide film as each of the first insulating layer and the second insulating layer. The adhesive strength between the first insulating layer and the second insulating layer can be increased by hydrophilic adhesion through hydroxyl groups (OH groups).

[0044] In the manufactured display device, the surface of the first conductive layer on the side of the second conductive layer is approximately the same height as the surface of the first insulating layer on the side of the second insulating layer. The surface of the second conductive layer on the side of the first conductive layer is approximately the same height as the surface of the second insulating layer on the side of the first insulating layer. Furthermore, in the present specification, etc., "A is approximately the same height as B" includes cases where the heights of A and B are the same, and cases where the heights of A and B are different due to manufacturing errors even if A and B are formed to have the same height.

[0045] A display device of one embodiment of the present invention preferably further comprises a third insulating layer and a fourth insulating layer. The third insulating layer is preferably located between a transistor and a first insulating layer. The fourth insulating layer is preferably located between a light-emitting diode and a second insulating layer. For each of the third insulating layer and the fourth insulating layer, it is preferable to use a film in which one or both of hydrogen and oxygen are less likely to diffuse than in the first insulating layer and the second insulating layer. The third insulating layer and the fourth insulating layer are preferably each comprising at least one of an aluminum oxide film, a hafnium oxide film, and a silicon nitride film. By using a film in which one or both of hydrogen and oxygen are less likely to diffuse than in a silicon oxide film, the diffusion of impurities from one of the stacked structure on the first substrate side and the stacked structure on the second substrate side to the other of these can be suppressed.

[0046] It is preferable that the angle between the side of the first conductive layer and the side of the transistor be greater than 0° and less than 90°, or greater than 0° and less than 90°. It is preferable that the angle between the side of the second conductive layer and the side of the transistor be greater than 90° and less than 180°, or greater than 90° and less than 180°. When both the first conductive layer and the second conductive layer are formed on the same substrate as the transistor, the first conductive layer and the second conductive layer are often formed such that the angle between the respective side of the first conductive layer and the second conductive layer and the side of the transistor is 90° or less. Accordingly, according to cross-sectional observation of the display device using a scanning electron microscope (SEM) or a scanning transmission electron microscope (STEM), the two conductive layers have different tapered shapes, so the boundary between these two conductive layers can be estimated as the interface of adhesion.

[0047] The display device of the present embodiment has the function of displaying an image using a light-emitting diode. When a light-emitting diode, which is a self-emissive device, is used as a display device, a backlight is unnecessary for the display device, and a polarizer does not need to be provided. Therefore, the power consumption of the display device can be reduced, and the display device can be made thin and light. A display device using a light-emitting diode as a display device has high brightness (e.g., 5000 cd / m²). 2 Ideally, 10,000 cd / m² 2 Above), because it has high contrast and a wide viewing angle, it can have high display quality. In addition, by using inorganic materials as light-emitting materials, the lifespan of the display device can be extended and reliability increased.

[0048] In this embodiment, an example in which a micro LED is used as a light-emitting diode is described in particular. In this embodiment, a micro LED having a double heterojunction is described. Furthermore, there are no particular limitations on the light-emitting diode, and, for example, a micro LED having a quantum well junction or a nanocolumn LED may be used.

[0049] The area of ​​the light-emitting region of a light-emitting diode is 1mm 2 The following is preferable, and 10,000 μm 2 The following is more preferable, and 3000μm 2 The following is more preferable, and 700μm 2 The following is even more preferable. In addition, the area of ​​the above region is 1 μm 2 The above is desirable, and 10μm 2 The above is more desirable, and 100μm 2 The above is more preferable. In addition, in this specification, etc., the area is 10,000 μm 2 Light-emitting diodes that include a light-emitting region of the following length are sometimes referred to as micro LEDs.

[0050] It is desirable for the transistor included in the display device to include a metal oxide in the channel-forming region. Transistors containing metal oxides have low power consumption. Therefore, by combining them with micro LEDs, a display device with extremely reduced power consumption can be realized.

[0051] In particular, the display device of the present embodiment preferably includes a transistor in which the height of the upper surface of the gate electrode and the upper surface of the insulating layer are approximately the same. For example, by flattening the upper surface of the gate electrode and the upper surface of the insulating layer using a flattening treatment such as chemical mechanical polishing (CMP), their upper surfaces become the same height.

[0052] Transistors with this structure can be easily reduced in size. Reducing the size of the transistor allows for a reduction in pixel size, which in turn increases the resolution of the display device.

[0053] Since the display device of the present embodiment can increase the resolution, it can be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type or bracelet-type information terminals (wearable devices), VR (virtual reality) devices such as head-mounted displays, glasses-type AR (augmented reality) devices, and MR (mixed reality) devices that can be mounted on the head.

[0054] [Example of Display Device Structure 1]

[0055] FIG. 1 is a cross-sectional view of a display device (100A). FIG. 2 (A), (B), and (C) are cross-sectional views showing the method of manufacturing the display device (100A).

[0056] The display device (100A) in FIG. 1 is formed by bonding the LED substrate (150A) shown in (A) of FIG. 2 and the circuit board (150B) shown in (B) of FIG. 2 together (see (C) of FIG. 2).

[0057] Figure 2 (A) is a cross-sectional view of an LED substrate (150A).

[0058] The LED substrate (150A) includes a substrate (101), a light-emitting diode (110a), a light-emitting diode (110b), an insulating layer (102), an insulating layer (103), and an insulating layer (104). The insulating layers (102, 103, and 104) may each have a single-layer structure or a stacked structure.

[0059] A light-emitting diode (110a) includes a semiconductor layer (113a), a light-emitting layer (114a), a semiconductor layer (115a), a conductive layer (116a), a conductive layer (116b), an electrode (117a), and an electrode (117b). A light-emitting diode (110b) includes a semiconductor layer (113b), a light-emitting layer (114b), a semiconductor layer (115b), a conductive layer (116c), a conductive layer (116d), an electrode (117c), and an electrode (117d). Each layer included in the light-emitting diode may have a single-layer structure or a stacked structure.

[0060] A semiconductor layer (113a) is provided on a substrate (101), a light-emitting layer (114a) is provided on the semiconductor layer (113a), and a semiconductor layer (115a) is provided on the light-emitting layer (114a). An electrode (117a) is electrically connected to the semiconductor layer (115a) through a conductive layer (116a). An electrode (117b) is electrically connected to the semiconductor layer (113a) through a conductive layer (116b).

[0061] A semiconductor layer (113b) is provided on a substrate (101), a light-emitting layer (114b) is provided on the semiconductor layer (113b), and a semiconductor layer (115b) is provided on the light-emitting layer (114b). An electrode (117c) is electrically connected to the semiconductor layer (115b) through a conductive layer (116c). An electrode (117d) is electrically connected to the semiconductor layer (113b) through a conductive layer (116d).

[0062] An insulating layer (102) is provided to cover a substrate (101), semiconductor layers (113a and 113b), light-emitting layers (114a and 114b), and semiconductor layers (115a and 115b). It is preferable that the insulating layer (102) has a flattening function. An insulating layer (103) is provided on top of the insulating layer (102). Conductive layers (116a, 116b, 116c, and 116d) are provided to fill the openings formed in the insulating layers (102 and 103). It is preferable that the upper surface of the conductive layers (116a, 116b, 116c, and 116d) has approximately the same height as the upper surface of the insulating layer (103). An insulating layer (104) is provided on top of the conductive layers (116a, 116b, 116c, and 116d) and the insulating layer (103). Electrodes (117a, 117b, 117c, and 117d) are provided to fill an opening formed in the insulating layer (104). It is preferable that the upper surface of the electrodes (117a, 117b, 117c, and 117d) has approximately the same height as the upper surface of the insulating layer (104).

[0063] The display device of the present embodiment includes at least one structure in which the upper surface of the insulating layer has approximately the same height as the upper surface of the conductive layer. An example of a method for manufacturing the above structure is a method of forming an insulating layer, providing an opening in the insulating layer, forming a conductive layer to fill the opening, and then performing a planarization treatment such as a CMP method. By doing so, the heights of the upper surface of the conductive layer and the upper surface of the insulating layer can be made equal.

[0064] The insulating layer (102) is preferably formed using an inorganic insulating material such as silicon oxide, silicon nitride, silicon nitride, silicon nitride, aluminum oxide, hafnium oxide, or titanium nitride.

[0065] In this specification and others, silicon nitride contains more oxygen than nitrogen. Silicon nitride contains more nitrogen than oxygen.

[0066] As for the insulating layer (103), a film in which one or both of hydrogen and oxygen are more difficult to diffuse than, for example, a silicon oxide film may be used. Examples of such films include aluminum oxide films, hafnium oxide films, and silicon nitride films. It is preferable that the insulating layer (103) function as a barrier layer to prevent impurities from diffusing from the LED substrate (150A) to the circuit board (150B).

[0067] It is particularly preferable to use an oxide insulating film as the insulating layer (104). The insulating layer (104) is a layer that is directly bonded to the insulating layer included in the circuit board (150B). By directly bonding the oxide insulating films to each other, the bonding strength (bonding strength) can be increased.

[0068] Examples of materials that can be used for the conductive layers (116a to 116d) include metals such as aluminum (Al), titanium, chromium, nickel, copper (Cu), yttrium, zirconium, tin (Sn), zinc (Zn), silver (Ag), platinum (Pt), gold (Au), molybdenum, tantalum, and tungsten (W), and alloys containing these metals as main components (e.g., an alloy of silver, palladium (Pd), and copper (Ag-Pd-Cu (APC)). Alternatively, oxides such as tin oxide or zinc oxide may be used.

[0069] For the electrodes (117a to 117d), for example, Cu, Al, Sn, Zn, W, Ag, Pt, or Au can be used. The electrodes (117a to 117d) are layers that are directly adhered to a conductive layer included in the circuit board (150B). To facilitate adhesion, it is preferable to use Cu, Al, W, or Au.

[0070] The light-emitting layer (114a) is located between the semiconductor layer (113a) and the semiconductor layer (115a). The light-emitting layer (114b) is located between the semiconductor layer (113b) and the semiconductor layer (115b). In the light-emitting layers (114a and 114b), electrons and holes combine to emit light. One of the semiconductor layers (113a and 113b) and the semiconductor layers (115a and 115b) is an n-type semiconductor layer, and the other is a p-type semiconductor layer.

[0071] A stacked structure comprising a semiconductor layer (113a), a light-emitting layer (114a), and a semiconductor layer (115a), and a stacked structure comprising a semiconductor layer (113b), a light-emitting layer (114b), and a semiconductor layer (115b) are each formed to emit light such as red, yellow, green, or blue. Any of the stacked structures may be formed to emit ultraviolet light. It is preferable that the two stacked structures emit light of different colors. For these stacked structures, compounds (also referred to as III-V compounds) including, for example, Group 13 elements and Group 15 elements may be used. Examples of Group 13 elements include aluminum, gallium, and indium. Examples of Group 15 elements include nitrogen, phosphorus, arsenic, and antimony. Light-emitting diodes can be formed using, for example, a compound of gallium and phosphorus, a compound of gallium and arsenic, a compound of gallium, aluminum, and arsenic, a compound of aluminum, gallium, indium, and phosphorus, gallium nitride (GaN), a compound of indium and gallium nitride, or a compound of selenium and zinc.

[0072] When the light-emitting diode (110a) and the light-emitting diode (110b) are formed to emit light of different colors, the step of forming a color conversion layer is unnecessary. Therefore, the manufacturing cost of the display device can be reduced.

[0073] Alternatively, two stacked structures may emit light of the same color. In this case, the light emitted from the light-emitting layers (114a and 114b) may be extracted to the outside of the display device through a color conversion layer and / or a coloring layer. Furthermore, a structure comprising light-emitting diodes in which each color pixel emits light of the same color will be described later in Example 2 of the structure of the display device.

[0074] The display device of the present embodiment may include a light-emitting diode that emits infrared light. The light-emitting diode that emits infrared light can be used, for example, as a light source for an infrared light sensor.

[0075] As the substrate (101), a compound semiconductor substrate may be used, for example, a compound semiconductor substrate containing group 13 elements and group 15 elements may be used. As the substrate (101), a single crystal substrate made of, for example, sapphire (Al2O3), silicon carbide (SiC), silicon (Si), or gallium nitride (GaN) may be used.

[0076] As shown in FIG. 1, light from the light-emitting diodes (110a and 110b) is emitted toward the substrate (101). Therefore, it is desirable for the substrate (101) to have transparency to visible light. For example, the transparency to visible light of the substrate (101) may be increased by reducing its thickness through polishing, etc.

[0077] Figure 2 (B) is a cross-sectional view of a circuit board (150B).

[0078] The circuit board (150B) includes a substrate (151), an insulating layer (152), a transistor (120a), a transistor (120b), a conductive layer (184a), a conductive layer (184b), a conductive layer (189a), a conductive layer (189b), an insulating layer (186), an insulating layer (187), an insulating layer (188), a conductive layer (190a), a conductive layer (190b), a conductive layer (190c), and a conductive layer (190d). The circuit board (150B) further includes insulating layers such as insulating layers (162, 181, 182, 183, and 185). Although one or more of these insulating layers may be considered as components of a transistor, they are not included as components of a transistor in the description of this embodiment. Additionally, each of the conductive layer and the insulating layer included in the circuit board (150B) may have a single-layer structure or a stacked structure.

[0079] As a substrate (151), an insulating substrate such as a glass substrate, a quartz substrate, a sapphire substrate, or a ceramic substrate; a single-crystal semiconductor substrate or a polycrystalline semiconductor substrate including silicon or silicon carbide as a material; a compound semiconductor substrate made of silicon germanium, etc.; or a semiconductor substrate such as an SOI (silicon on insulator) substrate may be used.

[0080] It is preferable that the substrate (151) blocks visible light (has non-transmittance to visible light). If the substrate (151) blocks visible light, it can suppress light from the outside from entering the transistors (120a and 120b) formed on the substrate (151). However, one embodiment of the present invention is not limited thereto, and the substrate (151) may have transmittance to visible light.

[0081] An insulating layer (152) is provided on the substrate (151). The insulating layer (152) functions as a barrier layer to prevent impurities such as water and hydrogen from diffusing from the substrate (151) to the transistors (120a and 120b), and to prevent oxygen from escaping from the metal oxide layer (165) to the insulating layer (152). As the insulating layer (152), a film that is more difficult for one or both of hydrogen and oxygen to diffuse than, for example, a silicon oxide film may be used. Examples of such films include aluminum oxide films, hafnium oxide films, and silicon nitride films.

[0082] The transistors (120a and 120b) each include a conductive layer (161), an insulating layer (163), an insulating layer (164), a metal oxide layer (165), a pair of conductive layers (166), an insulating layer (167), and a conductive layer (168), etc. Specific examples of transistors that can be used in a display device of one form of the present invention are described in detail in Embodiment 3.

[0083] The metal oxide layer (165) includes a channel-forming region. The metal oxide layer (165) includes a first region that overlaps with one of a pair of conductive layers (166), a second region that overlaps with the other of a pair of conductive layers (166), and a third region between the first region and the second region.

[0084] A conductive layer (161) and an insulating layer (162) are provided on an insulating layer (152), and insulating layers (163 and 164) are provided covering the conductive layer (161) and the insulating layer (162). A metal oxide layer (165) is provided on the insulating layer (164). The conductive layer (161) functions as a gate electrode, and the insulating layers (163 and 164) function as gate insulating layers. The conductive layer (161) overlaps with the metal oxide layer (165) through the insulating layers (163 and 164). It is preferable that the insulating layer (163) functions as a barrier layer, similar to the insulating layer (152). As for the insulating layer (164) in contact with the metal oxide layer (165), it is preferable to use an oxide insulating film such as a silicon oxide film.

[0085] Here, the upper surface of the conductive layer (161) is approximately the same height as the upper surface of the insulating layer (162). This allows the size of the transistors (120a and 120b) to be reduced.

[0086] A pair of conductive layers (166) are provided on the metal oxide layer (165) so as to be spaced apart from each other. The pair of conductive layers (166) function as a source and a drain. An insulating layer (181) is provided covering the metal oxide layer (165) and the pair of conductive layers (166), and an insulating layer (182) is provided on top of the insulating layer (181). An opening reaching the metal oxide layer (165) is provided in the insulating layer (181) and the insulating layer (182), and an insulating layer (167) and a conductive layer (168) are provided to fill this opening. The opening overlaps with the third region. The insulating layer (167) overlaps with the side of the insulating layers (181 and 182). The conductive layer (168) overlaps with the side of the insulating layers (181 and 182) through the insulating layer (167). The conductive layer (168) functions as a gate electrode, and the insulating layer (167) functions as a gate insulating layer. The conductive layer (168) overlaps with the metal oxide layer (165) through the insulating layer (167).

[0087] Here, the upper surface of the conductive layer (168) is approximately the same height as the upper surface of the insulating layer (182). This allows the size of the transistors (120a and 120b) to be reduced.

[0088] Insulating layers (183 and 185) are provided to cover the upper surfaces of insulating layers (182 and 167) and conductive layers (168). It is preferable that insulating layers (181 and 183) each function as barrier layers, such as insulating layer (152). If a pair of conductive layers (166) are covered with insulating layer (181), oxidation of the pair of conductive layers (166) due to oxygen contained in insulating layer (182) can be suppressed.

[0089] A plug electrically connected to one of a pair of conductive layers (166) and a conductive layer (189a) is provided to fill an opening provided in an insulating layer (181, 182, 183, and 185). The plug preferably comprises a conductive layer (184b) in contact with the side of the opening and the upper surface of one of the pair of conductive layers (166), and a conductive layer (184a) embedded inside the conductive layer (184b). Here, it is preferable to use a conductive material that is resistant to diffusion of hydrogen and oxygen as the conductive layer (184b).

[0090] A conductive layer (189a) and an insulating layer (186) are provided on an insulating layer (185), a conductive layer (189b) is provided on the conductive layer (189a), and an insulating layer (187) is provided on the insulating layer (186). It is preferable that the insulating layer (186) has a flattening function. Here, the upper surface of the conductive layer (189b) is approximately the same height as the upper surface of the insulating layer (187). An opening is provided in the insulating layers (187 and 186) that reaches the conductive layer (189a), and a conductive layer (189b) is provided to fill this opening. The conductive layer (189b) functions as a plug that electrically connects the conductive layer (189a) and the conductive layer (190a or 190c).

[0091] One of the pair of conductive layers (166) of the transistor (120a) is electrically connected to the conductive layer (190a) through the conductive layers (184a, 184b, 189a, and 189b).

[0092] Likewise, one of the pair of conductive layers (166) of the transistor (120b) is electrically connected to the conductive layer (190c) through the conductive layers (184a, 184b, 189a, and 189b).

[0093] The insulating layer (186) is preferably formed using an inorganic insulating material such as silicon oxide, silicon nitride, silicon nitride, silicon nitride, aluminum oxide, hafnium oxide, or titanium nitride.

[0094] As for the insulating layer (187), a film that is more difficult for one or both of hydrogen and oxygen to diffuse than, for example, a silicon oxide film may be used. Examples of such films include aluminum oxide films, hafnium oxide films, and silicon nitride films. It is preferable that the insulating layer (187) function as a barrier layer to prevent impurities (e.g. hydrogen and water) from diffusing from the LED substrate (150A) to the transistor. It is preferable that the insulating layer (187) function as a barrier layer to prevent impurities from diffusing from the circuit board (150B) to the LED substrate (150A).

[0095] The insulating layer (188) is a layer that is directly bonded to the insulating layer (104) included in the LED substrate (150A). It is preferable that the insulating layer (188) be formed using the same material as the insulating layer (104). It is preferable to use an oxide insulating film as the insulating layer (188). By directly bonding the oxide insulating films to each other, the bonding strength (bonding strength) can be increased. In addition, if one or both of the insulating layers (104 and 188) have a laminated structure, it is preferable that the layers in contact with each other (including the surface layer and the bonding surface) be formed using the same material.

[0096] The conductive layers (190a to 190d) are layers that are directly adhered to the electrodes (117a to 117d) of the LED substrate (150A). It is preferable that the main components of the conductive layers (190a to 190d) and the main components of the electrodes (117a to 117d) are the same metal element, and it is more preferable that the conductive layers (190a to 190d) and the electrodes (117a to 117d) are formed using the same material. For the conductive layers (190a to 190d), for example, Cu, Al, Sn, Zn, W, Ag, Pt, or Au may be used. It is preferable to use Cu, Al, W, or Au for easy adhesion. In addition, when one or both of the conductive layer (190) (conductive layers (190a to 190d)) and the electrode (117) (electrodes (117a to 117d)) have a laminated structure, it is preferable that the layers in contact with each other (including the surface layer and the adhesive surface) be formed using the same material.

[0097] Additionally, the circuit board (150B) may include one or both of a reflective layer that reflects light from a light-emitting diode and a light-blocking layer that blocks this light.

[0098] As shown in FIG. 1, the electrodes (117a, 117b, 117c, and 117d) provided on the LED substrate (150A) are each adhered to and electrically connected to the conductive layers (190a, 190b, 190c, and 190d) provided on the circuit board (150B).

[0099] For example, by connecting the electrode (117a) and the conductive layer (190a) to each other, the transistor (120a) and the light-emitting diode (110a) can be electrically connected to each other. The electrode (117a) functions as a pixel electrode of the light-emitting diode (110a). The electrode (117b) and the conductive layer (190b) are connected to each other. The electrode (117b) functions as a common electrode of the light-emitting diode (110a).

[0100] Likewise, by connecting the electrode (117c) and the conductive layer (190c) to each other, the transistor (120b) and the light-emitting diode (110b) can be electrically connected to each other. The electrode (117c) functions as a pixel electrode of the light-emitting diode (110b). The electrode (117d) and the conductive layer (190d) are connected to each other. The electrode (117d) functions as a common electrode of the light-emitting diode (110b).

[0101] It is preferable that the main components of the electrodes (117a, 117b, 117c, and 117d) and the main components of the conductive layers (190a, 190b, 190c, and 190d) are the same metal element.

[0102] The insulating layer (104) provided on the LED substrate (150A) and the insulating layer (188) provided on the circuit board (150B) are directly bonded to each other. It is preferable that the insulating layers (104 and 188) be formed using the same main component or the same material.

[0103] A connection having mechanical strength can be obtained by layers formed using the same material at the adhesive surface between the LED substrate (150A) and the circuit board (150B) coming into contact with each other.

[0104] To bond metal layers together, surface-activated bonding and diffusion bonding can be used. Surface-activated bonding is a method in which oxide films and impurity-adsorbing layers on the surface of metal layers are removed by sputtering or similar processes, and then the cleaned and activated surfaces of the metal layers are brought into contact and bonded. Diffusion bonding is a method in which the surfaces of metal layers are bonded together by adjusting both temperature and pressure. Since both of these methods can induce bonding at the atomic level, they can achieve bonding with excellent electrical and mechanical strength.

[0105] To bond insulating layers together, hydrophilic bonding can be used after achieving high flatness through methods such as polishing. Hydrophilic bonding is a method in which the surfaces of insulating layers treated with hydrophilicity using oxygen plasma are brought into contact and temporarily bonded, followed by final bonding through dehydration by heat treatment. Since hydrophilic bonding can induce bonding at the atomic level, a bond with excellent mechanical strength can be obtained. When using oxide insulating films, using hydrophilic treatment is desirable as it can further increase bond strength. Furthermore, when using oxide insulating films, hydrophilic treatment is not required.

[0106] Since both an insulating layer and a metal layer exist on the bonding surface between the LED substrate (150A) and the circuit board (150B), two or more bonding methods may be combined for bonding. For example, a combination of surface-activated bonding and hydrophilic bonding may be used.

[0107] For example, a method may be used in which the surface of the metal layer is cleaned after polishing, and then an anti-oxidation and hydrophilic treatment is applied to the surface of the metal layer, followed by bonding. Alternatively, a hydrophilic treatment may be performed on the surface of the metal layer using a non-oxidizing metal such as Au. If hydrophilic treatment is not performed, the anti-oxidation treatment can be omitted, and since there are no restrictions on the type of material, manufacturing costs can be reduced and the number of manufacturing steps can be cut. Furthermore, bonding methods other than the above may also be used.

[0108] In addition, the entire surface of the LED substrate (150A) and the circuit board (150B) does not necessarily need to be directly bonded, and at least a portion of these substrates may be connected to each other by a conductive paste such as silver, carbon, or copper, or by bumps such as gold or solder.

[0109] In addition, multiple light-emitting diodes may be electrically connected to a single transistor.

[0110] Next, a cross-sectional view of the display device (100B) is shown in FIG. 3.

[0111] An example is shown in which the transistors (120a) and (120b) of the display device (100B) have different channel lengths. The other components are the same as those of the display device (100A).

[0112] The transistor (120a) driving the light-emitting diode (110a) and the transistor (120b) driving the light-emitting diode (110b) may differ from each other in at least one of the size, channel length, channel width, and structure of the transistors. For example, if the light-emitting diode (110a) and the light-emitting diode (110b) emit light of different colors, the structure of the transistor may be changed for each color. Specifically, depending on the amount of current required for light emission with a desired brightness, one or both of the channel length and channel width of the transistor may be changed for each color.

[0113] Next, FIG. 4 is a cross-sectional view of a display device (100C).

[0114] The display device (100C) has a stacked structure comprising a transistor (transistor (130a and 130b)) each having a channel forming region in a substrate (131) and a transistor (transistor (120a and 120b)) each having a channel forming region in a metal oxide layer.

[0115] As for the substrate (131), it is suitable to use a single-crystal silicon substrate. The transistors (130a and 130b) each include a conductive layer (135), an insulating layer (134), an insulating layer (136), and a pair of low-resistance regions (133). The conductive layer (135) functions as a gate. The insulating layer (134) is located between the conductive layer (135) and the substrate (131) and functions as a gate insulating layer. The insulating layer (136) is provided to cover the side of the conductive layer (135) and functions as a sidewall. The pair of low-resistance regions (133) on the substrate (131) are doped with impurities, and one of the pair of low-resistance regions (133) functions as the source of the transistor, and the other functions as the drain of the transistor.

[0116] A device isolation layer (132) is provided between two adjacent transistors so as to be embedded in the substrate (131).

[0117] An insulating layer (139) is provided covering the transistors (130a and 130b), and a conductive layer (138) is provided on the insulating layer (139). The conductive layer (138) is electrically connected to one of a pair of low-resistance regions (133) through a conductive layer (137) provided to fill the opening of the insulating layer (139). An insulating layer (141) is provided covering the conductive layer (138), and a conductive layer (142) is provided on the insulating layer (141). The conductive layer (138) and the conductive layer (142) each function as wiring. An insulating layer (143) and an insulating layer (152) are provided covering the conductive layer (142), and transistors (120a and 120b) are provided on the insulating layer (152). Since the stacked structure from the insulating layer (152) to the substrate (101) is the same as that of the display device (100A), a detailed description thereof is omitted.

[0118] Transistors (120a and 120b) can be used as transistors included in a pixel circuit. Transistors (130a and 130b) can each be used as transistors included in a pixel circuit or as transistors included in a driving circuit (one or both of a gate driver and a source driver) for driving the pixel circuit. Transistors (120a, 120b, 130a, and 130b) can also be used as transistors included in various circuits such as arithmetic circuits and memory circuits.

[0119] By having this structure, not only the pixel circuit but also the driving circuit can be formed directly below the light-emitting diode, so the display device can be miniaturized compared to the case where the driving circuit is provided on the outside of the display area. In addition, it is possible to make a display device with a narrow frame (narrow non-display area).

[0120] [Example of Display Device Structure 2]

[0121] Figure 5 (A) is a cross-sectional view of a display device (100D), and Figure 5 (B) is a cross-sectional view of a display device (100E).

[0122] Each of the display devices (100D and 100E) includes a light-emitting diode in which each pixel of a color emits light of the same color.

[0123] The display devices (100D and 100E) each include a substrate (191) provided with a coloring layer (CFR) and a color conversion layer (CCMR).

[0124] Specifically, the substrate (191) includes a coloring layer (CFR) and a color conversion layer (CCMR) in an area overlapping with the red pixel light-emitting diode (110a). The color conversion layer (CCMR) has the function of converting blue light into red light.

[0125] In Figures 5 (A) and (B), light emitted from the light-emitting diode (110a) of the red pixel is converted from blue light to red light by a color conversion layer (CCMR), the purity of the red light is enhanced by a coloring layer (CFR), and the red light is emitted outside of the display device (100D or 100E).

[0126] Although not shown in the drawing, the substrate (191) likewise includes a green coloring layer in an area overlapping with the light-emitting diode of the green pixel and a color conversion layer that converts blue light into green light. Accordingly, light emitted from the light-emitting diode of the green pixel is converted from blue light into green light by the color conversion layer, the purity of the green light is enhanced by the coloring layer, and the green light is emitted to the outside of the display device.

[0127] Meanwhile, a color conversion layer is not provided in the area of ​​the substrate (191) that overlaps with the blue pixel light-emitting diode (110b). The substrate (191) may include a blue coloring layer in the area that overlaps with the blue pixel light-emitting diode (110b). If a blue coloring layer is provided, the purity of the blue light can be improved. If a blue coloring layer is not provided, the manufacturing process can be simplified.

[0128] Blue light emitted from the light-emitting diode (110b) is emitted to the outside of the display device (100D or 100E) through the adhesive layer (192) and the substrate (191).

[0129] In the fabrication of a display device comprising light-emitting diodes having the same structure for each color pixel, since only light-emitting diodes of the same type are formed on a substrate, the fabrication device and the fabrication process can be simplified compared to the case where multiple types of light-emitting diodes are formed.

[0130] Since the substrate (191) is located on the side that extracts light from the light-emitting diode, it is preferable to use a material with high transmittance to visible light as the substrate (191). Examples of materials that can be used for the substrate (191) include glass, quartz, sapphire, and resin. A film such as a resin film may also be used as the substrate (191). In this case, the weight and thickness of the display device can be reduced.

[0131] As a color conversion layer, it is preferable to use a phosphor or a quantum dot (QD). In particular, since quantum dots have a narrow peak in their emission spectrum, they can obtain emission with high color purity. This can improve the display quality of the display device.

[0132] The color conversion layer can be formed by droplet extrusion (e.g., inkjet method), coating, imprinting, or various printing methods (screen printing or offset printing). Additionally, a color conversion film such as a quantum dot film may be used.

[0133] To process a film that serves as a color conversion layer, it is preferable to employ a photolithography method. Examples of photolithography methods include a method of forming a resist mask on a thin film to be processed, processing the thin film by etching or the like, and removing the resist mask, and a method of forming a photosensitive thin film, exposing the photosensitive thin film to light, and developing it to process it into a desired shape. For example, a thin film can be formed using a material in which quantum dots are mixed with photoresist, and by processing the thin film using a photolithography method, an island-shaped color conversion layer can be formed.

[0134] There are no limitations on the materials of quantum dots, and examples include group 14 elements, group 15 elements, group 16 elements, compounds of multiple group 14 elements, compounds of an element belonging to any of groups 4 to 14 and a group 16 element, compounds of a group 2 element and a group 16 element, compounds of a group 13 element and a group 15 element, compounds of a group 13 element and a group 17 element, compounds of a group 14 element and a group 15 element, compounds of a group 11 element and a group 17 element, iron oxides, titanium oxides, chalcogenide spinels, and various semiconductor clusters.

[0135] Specific examples include cadmium selenide; cadmium sulfide; cadmium telluride; zinc selenide; zinc oxide; zinc sulfide; zinc telluride; mercury sulfide; mercury selenide; mercury telluride; indium arsenide; indium phosphide; gallium arsenide; gallium phosphide; indium nitride; gallium nitride; indium antimonide; gallium antimonide; aluminum phosphide; aluminum arsenide; aluminum antimonide; lead selenide; lead telluride; lead sulfide; indium selenide; indium telluride; indium sulfide; gallium selenide; arsenic sulfide; arsenic selenide; arsenic telluride; antimony sulfide; antimony selenide; antimony telluride; bismuth sulfide; bismuth selenide; bismuth telluride; silicon; silicon carbide; germanium; tin; Selenium; Tellurium; Boron; Carbon; Phosphorus; Boron nitride; Boron phosphide; Boron arsenide; Aluminum nitride; Aluminum sulfide; Barium sulfide; Barium selenide; Barium telluride; Calcium sulfide; Calcium selenide; Calcium telluride; Beryllium sulfide; Beryllium selenide; Beryllium telluride; Magnesium sulfide; Magnesium selenide; Germanium sulfide; Germanium selenide; Germanium telluride; Tin sulfide; Tin selenide; Tin telluride; Lead oxide; Copper fluoride; Copper chloride; Copper bromide; Copper iodide; Copper oxide; Copper selenide; Nickel oxide; Cobalt oxide; Cobalt sulfide; Iron oxide; Iron sulfide; Manganese oxide; Molybdenum sulfide; Vanadium oxide; Tungsten oxide; Tantalum oxide; Titanium oxide; Zirconium oxide; silicon nitride; germanium nitride; aluminum oxide; barium titanate; compounds of selenium, zinc, and cadmium; compounds of indium, arsenic, and phosphorus; compounds of cadmium, selenium, and sulfur; compounds of cadmium, selenium, and tellurium; compounds of indium, gallium, and arsenic; compounds of indium, gallium, and selenium; compounds of indium, selenium, and sulfur; compounds of copper, indium, and sulfur; and combinations thereof are included, but not limited to these. So-called alloy-type quantum dots, in which the composition is expressed in any proportion, may also be used.

[0136] Examples of quantum dots include core-type quantum dots, core-shell quantum dots, and core-multishell quantum dots. Because quantum dots have a high proportion of surface atoms, they are highly reactive and prone to aggregation. For this reason, it is desirable to attach a protective agent or provide a protective group to the surface of the quantum dots. By attaching the protective agent or providing the protective group, aggregation can be prevented and solubility in a solvent can be increased. Reactivity can also be reduced and electrical stability improved.

[0137] Since the band gap of quantum dots increases as their size decreases, their size is appropriately adjusted to obtain light of the desired wavelength. As the crystal size decreases, the light emission from the quantum dots shifts toward the blue side, that is, the high-energy side; therefore, by changing the size of the quantum dots, the emission wavelengths of the quantum dots can be adjusted across the wavelength ranges of the spectrum in the ultraviolet, visible, and infrared regions. The range of the quantum dot size (diameter) is, for example, 0.5 nm or more and 20 nm or less, preferably 1 nm or more and 10 nm or less. As the size distribution of the quantum dots decreases, the emission spectrum narrows, allowing for the acquisition of light with high color purity. The shape of the quantum dots is not particularly limited and may be spherical, rod-shaped, or circular. Quantum rods, which are rod-shaped quantum dots, have the function of emitting directional light.

[0138] A colored layer is a colored layer that transmits light within a specific wavelength range. For example, a color filter that transmits light within the wavelength ranges of red, green, blue, or yellow can be used. Examples of materials that can be used for the colored layer include metallic materials, resin materials, and resin materials containing pigments or dyes.

[0139] A display device (100D) can be manufactured by first bonding a circuit board and an LED board together as in the case of a display device (100A), peeling off the substrate (101) of the LED board, and then bonding a substrate (191) provided with a coloring layer (CFR) and a color conversion layer (CCMR), etc., to the surface exposed by peeling using an adhesive layer (192).

[0140] There are no limitations on the method of peeling off the substrate (101), and, for example, as shown in (A) of FIG. 6, a method of irradiating a laser beam over the entire surface of the substrate (101) may be used. By doing so, the substrate (101) can be peeled off, and the insulating layer (102) and the light-emitting diodes (110a and 110b) can be exposed ((B) of FIG. 6).

[0141] As for the laser, an excimer laser or a solid-state laser can be used. For example, a diode-pumped solid-state (DPSS) laser may be used.

[0142] A peeling layer may be provided between the substrate (101) and the light-emitting diodes (110a and 110b).

[0143] The exfoliation layer can be formed using organic or inorganic materials.

[0144] Examples of organic materials that can be used in the release layer include polyimide resin, acrylic resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, and phenol resin.

[0145] Examples of inorganic materials that can be used in the peeling layer include metals containing elements selected from tungsten, molybdenum, titanium, tantalum, niobium, nickel, cobalt, zirconium, zinc, ruthenium, rhodium, palladium, osmium, iridium, and silicon, alloys containing said elements, and compounds containing said elements. The crystal structure of the silicon-containing layer may be amorphous, microcrystalline, or polycrystalline.

[0146] As the adhesive layer (192), any of the various curing adhesives such as reaction-curing adhesives, heat-curing adhesives, and anaerobic adhesives, and photo-curing adhesives such as UV-curing adhesives may be used. An adhesive sheet may also be used.

[0147] Alternatively, a substrate (191) provided with a coloring layer (CFR) and a color conversion layer (CCMR), etc., such as a display device (100E), may be bonded to a substrate (101) using an adhesive layer (192). That is, the substrate (101) does not need to be peeled off.

[0148] At this time, it is preferable to thin the substrate (101) by polishing, etc. By doing so, the extraction efficiency of light emitted from the light-emitting diode can be increased. In addition, the display device can be made thin and light.

[0149] A display device (100E) can be manufactured by first bonding a circuit board and an LED board together as in the case of a display device (100A), polishing the substrate (101) of the LED board, and then bonding a substrate (191) provided with a coloring layer (CFR) and a color conversion layer (CCMR), etc., to the polished surface of the substrate (101) using an adhesive layer (192).

[0150] [Example of Display Device Structure 3]

[0151] Figure 7 is a cross-sectional view of a display device (100F).

[0152] A display device of one embodiment of the present invention may be a display device equipped with a touch sensor (such a display device may also be referred to as an input / output device or a touch panel). Any structure of the above-described display device may be applied to a touch panel. A display device (100F) is an example in which a touch sensor is provided on a display device (100A).

[0153] There are no particular limitations on the sensing device (also referred to as a sensor device, a sensing element, or a sensor element) included in a touch panel of one embodiment of the present invention. Various sensors capable of detecting proximity or contact of a sensed object, such as a finger or a stylus, may be used as the sensing device.

[0154] Various methods can be used for sensors, such as capacitive, resistive, surface acoustic wave, infrared, optical, and pressure-sensitive methods.

[0155] In this embodiment, a touch panel including a capacitive sensing device is described as an example.

[0156] Examples of capacitive touch sensing devices include surface-type capacitive touch sensing devices and projected-type capacitive touch sensing devices. Examples of projected-type capacitive touch sensing devices include magnetic-capacitive touch sensing devices and mutual-capacitive touch sensing devices. Using mutual-capacitive touch sensing devices is desirable because it allows for the simultaneous detection of multiple points.

[0157] A touch panel of one embodiment of the present invention may have any of various structures, including a structure for bonding separately formed display devices and sensing devices together, and a structure for providing electrodes, etc., included in the sensing device on one or both of a substrate supporting the display device and a counter-substrate.

[0158] Since the stacked structure from the substrate (151) of the display device (100F) to the substrate (101) is the same as that of the display device (100A), a detailed description thereof is omitted.

[0159] The conductive layer (189c) is electrically connected to FPC1 through the conductive layer (189d), the conductive layer (190e), and the conductive layer (195). Signal and power are supplied to the display device (100F) through FPC1.

[0160] The conductive layer (189c) can be formed in the same step using the same material as the conductive layer (189a). The conductive layer (189d) can be formed in the same step using the same material as the conductive layer (189b). The conductive layer (190e) can be formed in the same step using the same material as the conductive layers (190a to 190d).

[0161] As for the conductive layer (195), for example, anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) can be used.

[0162] A touch sensor is provided on the substrate (171). The substrate (171) and the substrate (101) are bonded together by an adhesive layer (179) such that the side of the substrate (171) on which the touch sensor is provided faces the substrate (101).

[0163] Electrodes (177) and (178) are provided on the side of the substrate (171) facing the substrate (101). Electrodes (177 and 178) are formed on the same plane. The electrodes (177 and 178) use a material that transmits visible light. An insulating layer (173) is provided to cover the electrodes (177 and 178). Electrode (174) is electrically connected to two electrodes (178) provided on both sides of electrode (177) through an opening provided in the insulating layer (173).

[0164] A wiring (172) obtained by processing a conductive layer such as electrodes (177 and 178) is connected to a conductive layer (175) obtained by processing a conductive layer such as electrode (174). The conductive layer (175) is electrically connected to FPC2 through a connector (176).

[0165] As described above, since the display device of the present embodiment can be manufactured by bonding a plurality of light-emitting diodes and a plurality of transistors at once, the manufacturing cost of the display device is reduced and the yield is improved. In addition, by combining a micro LED with a transistor including a metal oxide, a display device with reduced power consumption can be obtained.

[0166] In the display device of the present embodiment, a first insulating layer over a plurality of transistors and a second insulating layer over a plurality of light-emitting diodes are formed using a film of the same material (preferably an oxide insulating film, more preferably a silicon oxide film). By directly bonding the first insulating layer and the second insulating layer, the bonding strength can be increased. A third insulating layer is provided between the plurality of transistors and the first insulating layer, and a fourth insulating layer is provided between the plurality of light-emitting diodes and the second insulating layer. For each of the third insulating layer and the fourth insulating layer, a film in which one or both of hydrogen and oxygen are less likely to diffuse than in the first insulating layer and the second insulating layer (preferably an aluminum oxide film, a hafnium oxide film, and a silicon nitride film, more preferably a silicon nitride film) is used. By doing so, it is suitably possible to prevent impurities from entering the transistors and light-emitting diodes.

[0167] In the display device of the present embodiment, since the size of the transistor can be reduced, it becomes easy to increase the resolution of the display device and to apply it to electronic devices having a relatively small display area.

[0168] This embodiment may be appropriately combined with any of the other embodiments. In this specification, where multiple structural examples are presented in one embodiment, the structural examples may be appropriately combined.

[0169] (Embodiment 2)

[0170] In this embodiment, a display device of one form of the present invention will be described with reference to FIGS. 8, FIGS. 9, FIGS. 10 (A) and (B), FIGS. 11, FIGS. 12, and FIGS. 13.

[0171] The display devices (100D and 100E) described in Example 2 of the structure of the display device of Embodiment 1 ((A) and (B) of FIG. 5) are examples in which a substrate provided with a color conversion layer is attached to a substrate provided with a transistor and a light-emitting diode, respectively, but the present invention is not limited thereto.

[0172] In this embodiment, an example is presented in which a substrate on the light-emitting diode side is peeled off and a color conversion layer is formed on the surface exposed by this peeling.

[0173] In addition, detailed descriptions of components such as those in Embodiment 1 may be omitted.

[0174] The display device of the present embodiment includes a plurality of light-emitting diodes that are display devices and a plurality of transistors that drive the display devices. The plurality of light-emitting diodes are arranged in a matrix. Each of the plurality of transistors is electrically connected to at least one of the plurality of light-emitting diodes.

[0175] The display device of the present embodiment is formed by bonding a plurality of transistors formed on a substrate and a plurality of light-emitting diodes formed on another substrate.

[0176] In the method for manufacturing a display device according to the present embodiment, since a plurality of light-emitting diodes and a plurality of transistors are bonded together at once, even when manufacturing a display device with a large number of pixels or high precision, the manufacturing time of the display device can be shortened and the difficulty of manufacturing can be lowered compared to the case of mounting light-emitting diodes one by one on a circuit board.

[0177] The display device of the present embodiment has a stacked structure comprising a transistor having a channel forming region in a semiconductor substrate and a transistor having a channel forming region in a metal oxide layer. With this structure, high-speed operation of the circuit is enabled, and power consumption can be drastically reduced.

[0178] A method for manufacturing a display device of one embodiment of the present invention first forms a plurality of first transistors, each including a channel forming region, on a first substrate, forms a plurality of second transistors as a matrix on the plurality of first transistors, and forms a first insulating layer and a plurality of first conductive layers on the plurality of second transistors. Each of the plurality of first conductive layers is electrically connected to at least one of the plurality of second transistors. Here, the first insulating layer and the first conductive layer are formed such that the upper surface of the first insulating layer and the upper surface of the first conductive layer are of the same height. A plurality of light-emitting diodes are formed as a matrix on a second substrate, and a second insulating layer and a plurality of second conductive layers are formed on the plurality of light-emitting diodes. Each of the plurality of second conductive layers is electrically connected to at least one of the plurality of light-emitting diodes. Here, the second insulating layer and the second conductive layer are formed such that the upper surface of the second insulating layer and the upper surface of the second conductive layer are of the same height.

[0179] A first substrate and a second substrate are bonded together so that each of a plurality of second transistors is electrically connected to at least one of a plurality of light-emitting diodes. By bonding the first substrate and the second substrate, a plurality of light-emitting diodes and a plurality of second transistors can be bonded together at once. Specifically, each of a plurality of first conductive layers is directly bonded to at least one of a plurality of second conductive layers. By doing so, the second transistor can be electrically connected to the light-emitting diode through the first conductive layer and the second conductive layer. It is preferable that the first conductive layer and the second conductive layer contain the same metal element as their main components, and it is more preferable that the first conductive layer and the second conductive layer are formed using the same material. The metal element is preferably gold, aluminum, tungsten, or copper, and gold is particularly preferred. This increases the bonding strength between the first conductive layer and the second conductive layer. The first insulating layer is directly bonded to the second insulating layer. It is preferable that the first insulating layer and the second insulating layer be formed using the same material, and in particular, it is preferable to use a silicon oxide film as each of the first insulating layer and the second insulating layer.

[0180] After that, the second substrate is peeled off, and at least one of a coloring layer, a color conversion layer, and a light-blocking layer is formed on the surface exposed by this peeling.

[0181] In one embodiment of the present invention, a display device preferably includes a light-emitting diode that emits light of the same color for each color pixel. As a result, the manufacturing of the display device is facilitated, the process is simplified, and the yield is improved.

[0182] In this embodiment, an example is described in which each color pixel includes a light-emitting diode that emits blue light. In the blue pixel, the blue light emitted by the light-emitting diode does not pass through the color conversion layer and is extracted to the outside of the display device. In each of the red pixel and the green pixel, the blue light emitted by the light-emitting diode is converted into red light or green light by the color conversion layer and extracted to the outside of the display device.

[0183] It is desirable that the light emitted from the light-emitting diode in each color pixel be extracted to the outside through a coloring layer. This allows for an increase in the color purity of the light. Additionally, a coloring layer does not need to be provided for at least one color pixel. If a coloring layer is not provided, the light emitted from the light-emitting diode can be efficiently extracted to the outside of the display device.

[0184] It is desirable to provide a light-blocking layer between pixels of each color. By doing so, light emitted from a light-emitting diode can be suppressed from entering adjacent pixels (also known as light crosstalk). Consequently, the display quality of the display device can be improved.

[0185] In the manufactured display device, the surface of the first conductive layer on the side of the second conductive layer is approximately the same height as the surface of the first insulating layer on the side of the second insulating layer. The surface of the second conductive layer on the side of the first conductive layer is approximately the same height as the surface of the second insulating layer on the side of the first insulating layer.

[0186] It is preferable that the display device includes a transistor containing silicon in the channel forming region and a transistor containing a metal oxide in the channel forming region. For example, a transistor containing a metal oxide in the channel forming region may be used in a pixel circuit and a gate driver, and a transistor containing silicon in the channel forming region may be used in a source driver. Alternatively, for example, a transistor containing a metal oxide in the channel forming region may be used in a pixel circuit, and a transistor containing silicon in the channel forming region may be used in a source driver and a gate driver. Alternatively, a transistor containing silicon in the channel forming region and / or a transistor containing a metal oxide in the channel forming region may be used as a transistor included in various circuits such as an arithmetic circuit and a memory circuit.

[0187] <Example of Display Device Structure 4>

[0188] FIG. 8 is a cross-sectional view of a display device (100G). FIG. 9 is a cross-sectional view of a display device (100H). FIG. 10 (A) and (B), FIG. 11, FIG. 12, and FIG. 13 are cross-sectional views showing a method of manufacturing a display device (100G).

[0189] Each of the display device (100G) and the display device (100H) includes a transistor (130a, 130b, and 130c) each having silicon in a channel forming region, a transistor (120a, 120b, and 120c) each having a metal oxide in a channel forming region, and a light-emitting diode (110a, 110b, and 110c).

[0190] In the display device (100G and 100H), each pixel of a color includes a light-emitting diode that emits blue light.

[0191] In the display device (100G and 100H), a coloring layer (CFR) and a color conversion layer (CCMR) are provided in an area overlapping with the red pixel light-emitting diode (110a). The color conversion layer (CCMR) has the function of converting blue light into red light.

[0192] Light emitted from the light-emitting diode (110a) is converted from blue light to red light by a color conversion layer (CCMR), the purity of the red light is enhanced by a coloring layer (CFR), and the red light is emitted outside of the display device (100G or 100H).

[0193] Likewise, in the display device (100G and 100H), a green coloring layer (CFG) and a color conversion layer (CCMG) that converts blue light into green light are provided in an area overlapping with the light-emitting diode (110c) of the green pixel. Accordingly, light emitted from the light-emitting diode (110c) is converted from blue light into green light by the color conversion layer (CCMG), the purity of the green light is enhanced by the coloring layer (CFG), and the green light is emitted outside the display device (100G or 100H).

[0194] Meanwhile, in the display device (100G and 100H), a color conversion layer is not provided in the area overlapping with the light-emitting diode (110b) of the blue pixel. The blue light emitted from the light-emitting diode (110b) is not color-converted and is emitted outside the display device (100G or 100H) through the coloring layer (CFB).

[0195] In a display device (100G or 100H), it is preferable to provide a blue coloring layer (CFB) in an area overlapping with a blue pixel light-emitting diode (110b). In this case, the purity of the blue light can be increased. If the blue coloring layer (CFB) is not provided, the manufacturing process can be simplified. In addition, if the blue coloring layer (CFB) is not provided, the light emitted from the light-emitting diode (110b) can be efficiently extracted to the outside of the display device.

[0196] In the fabrication of display devices (100G and 100H) in which each color pixel includes a light-emitting diode having the same structure, only light-emitting diodes of the same type are formed on the substrate, so the fabrication device and the fabrication process can be simplified compared to the case where multiple types of light-emitting diodes are formed.

[0197] A light-blocking layer (106) is provided between pixels of each color. The light-blocking layer (106) is provided on the underlayer (109). By the light-blocking layer (106), light emitted from the light-emitting diode can be prevented from entering adjacent pixels of other colors. Thus, the display quality of the display device can be improved.

[0198] The display device (100H) of FIG. 9 differs from the display device (100G) of FIG. 8 in that a light-blocking layer (105) is provided. A display device of one embodiment of the present invention preferably includes a light-blocking layer (105). The light-blocking layer (105) is provided to fill an opening provided in the underlayer (109), insulating layer (102), insulating layer (103), and insulating layer (104). By the light-blocking layer (105), light emitted from a light-emitting diode can be prevented from entering an adjacent pixel of a different color. Thus, the display quality of the display device can be improved. Additionally, an opening does not need to be provided in the underlayer (109) or the insulating layer (104). The light-blocking layer (105) may be formed to fill an opening provided in at least one of the underlayer (109), insulating layer (102), insulating layer (103), and insulating layer (104).

[0199] There are no particular limitations on the material of the light-blocking layer (106 and 105), and for example, inorganic materials such as metal materials, or organic materials such as resin materials containing pigments (e.g., carbon black) or dyes may be used. Alternatively, the light-blocking layer may be formed by laminating color filters used in all colored layers. For example, the light-blocking layer may be formed by laminating three color filters of red, green, and blue.

[0200] The display device (100G) shown in FIG. 8 can be manufactured by first bonding the LED substrate (150C) shown in FIG. 10 (A) and the circuit board (150D) shown in FIG. 10 (B) together (see FIG. 11), peeling off the substrate (101) of the LED substrate (150C) (see FIG. 12 and FIG. 13), and forming a coloring layer, a color conversion layer, and a light-blocking layer (106), etc., on the surface exposed by this peeling.

[0201] (A) of FIG. 10 is a cross-sectional view of an LED substrate (150C).

[0202] The LED substrate (150C) includes a substrate (101), a lower film (109), a light-emitting diode (110a), a light-emitting diode (110b), a light-emitting diode (110c), an insulating layer (102), an insulating layer (103), and an insulating layer (104). The lower film (109), the insulating layer (102), the insulating layer (103), and the insulating layer (104) may each have a single-layer structure or a stacked structure. Additionally, when manufacturing the display device (100H) of FIG. 9, the LED substrate (150C) further includes a light-blocking layer (105).

[0203] Light-emitting diodes (110a, 110b, and 110c) emit light of the same color. Each light-emitting diode includes a semiconductor layer (113), a light-emitting layer (114), and a semiconductor layer (115). Light-emitting diode (110a) further includes a conductive layer (116a), a conductive layer (116b), an electrode (117a), and an electrode (117b). Light-emitting diode (110b) further includes a conductive layer (116c), a conductive layer (116d), an electrode (117c), and an electrode (117d). Light-emitting diode (110c) further includes a conductive layer (116e), a conductive layer (116f), an electrode (117e), and an electrode (117f). Each layer included in the light-emitting diode may have a single-layer structure or a stacked structure.

[0204] A lower film (109) is provided on a substrate (101), a semiconductor layer (113) is provided on the lower film (109), a light-emitting layer (114) is provided on the semiconductor layer (113), and a semiconductor layer (115) is provided on the light-emitting layer (114).

[0205] The electrode (117a) is electrically connected to the semiconductor layer (115) included in the light-emitting diode (110a) through the conductive layer (116a). The electrode (117b) is electrically connected to the semiconductor layer (113) included in the light-emitting diode (110a) through the conductive layer (116b).

[0206] Likewise, the electrode (117c) is electrically connected to the semiconductor layer (115) included in the light-emitting diode (110b) through the conductive layer (116c). The electrode (117d) is electrically connected to the semiconductor layer (113) included in the light-emitting diode (110b) through the conductive layer (116d).

[0207] The electrode (117e) is electrically connected to the semiconductor layer (115) included in the light-emitting diode (110c) through the conductive layer (116e). The electrode (117f) is electrically connected to the semiconductor layer (113) included in the light-emitting diode (110c) through the conductive layer (116f).

[0208] An insulating layer (102) is provided to cover a substrate (101), a semiconductor layer (113), a light-emitting layer (114), and a semiconductor layer (115). It is preferable that the insulating layer (102) has a flattening function. An insulating layer (103) is provided on top of the insulating layer (102). Conductive layers (116a, 116b, 116c, 116d, 116e, and 116f) are provided to fill the openings provided in the insulating layer (102) and the insulating layer (103). It is preferable that the upper surface of the conductive layers (116a, 116b, 116c, 116d, 116e, and 116f) has approximately the same height as the upper surface of the insulating layer (103). An insulating layer (104) is provided on the conductive layer (116a, 116b, 116c, 116d, 116e, and 116f) and the insulating layer (103). Electrodes (117a, 117b, 117c, 117d, 117e, and 117f) are provided to fill the openings provided in the insulating layer (104). It is preferable that the upper surface of the electrodes (117a, 117b, 117c, 117d, 117e, and 117f) has approximately the same height as the upper surface of the insulating layer (104).

[0209] The display device of the present embodiment includes at least one structure in which the upper surface of the insulating layer has approximately the same height as the upper surface of the conductive layer. An example of a method for manufacturing the above structure is a method of forming an insulating layer, providing an opening in the insulating layer, forming a conductive layer to fill the opening, and then performing a planarization treatment such as a CMP method. By doing so, the heights of the upper surface of the conductive layer and the upper surface of the insulating layer can be made equal.

[0210] For materials that can be used for components of the LED substrate (150C), refer to Embodiment 1.

[0211] The lower film (109) is preferably formed using an inorganic insulating material such as silicon oxide, silicon nitride, silicon nitride, silicon nitride, aluminum oxide, hafnium oxide, or titanium nitride.

[0212] As for the insulating layer (103), for example, a film in which one or both of hydrogen and oxygen are more difficult to diffuse than a silicon oxide film may be used. It is preferable that the insulating layer (103) functions as a barrier layer to prevent impurities from diffusing from the LED substrate (150C) to the circuit board (150D).

[0213] It is particularly preferable to use an oxide insulating film as the insulating layer (104). The insulating layer (104) is a layer that is directly bonded to the insulating layer included in the circuit board (150D). By directly bonding the oxide insulating films to each other, the bonding strength (bonding strength) can be increased.

[0214] For the electrodes (117a to 117d), for example, Cu, Al, Sn, Zn, W, Ag, Pt, or Au can be used. The electrodes (117a to 117d) are layers that are directly adhered to a conductive layer included in the circuit board (150D). To facilitate adhesion, it is preferable to use Cu, Al, W, or Au.

[0215] As the substrate (101), a single-crystal substrate made of, for example, sapphire (Al2O3), silicon carbide (SiC), silicon (Si), or gallium nitride (GaN) may be used. In addition, in this embodiment, since the substrate (101) is peeled off in a subsequent step, the substrate (101) does not need to be transparent to visible light.

[0216] (B) of FIG. 10 is a cross-sectional view of a circuit board (150D).

[0217] Since the circuit board (150D) has a structure similar to the stacked structure from the substrate (131) to the insulating layer (188) of the display device (100C) shown in FIG. 4, a detailed description thereof may be omitted. For materials that can be used for the components of the circuit board (150D), reference may be made to Embodiment 1.

[0218] The circuit board (150D) has a stacked structure comprising a transistor (transistor (130a, 130b, and 130c)) each having a channel forming region in the substrate (131) and a transistor (transistor (120a, 120b, and 120c)) each having a channel forming region in the metal oxide layer. Additionally, each layer included in the circuit board (150D) may be a single-layer structure or a stacked structure.

[0219] It is preferable to use a single-crystal silicon substrate as the substrate (131). Alternatively, a compound semiconductor substrate may be used as the substrate (131).

[0220] The transistors (130a, 130b, and 130c) each comprise a conductive layer (135), an insulating layer (134), an insulating layer (136), and a pair of low-resistance regions (133). The conductive layer (135) functions as a gate. The insulating layer (134) is located between the conductive layer (135) and the substrate (131) and functions as a gate insulating layer. The insulating layer (136) is provided to cover the side of the conductive layer (135) and functions as a sidewall. The pair of low-resistance regions (133) on the substrate (131) are doped with impurities, and one of the pair of low-resistance regions (133) functions as the source of the transistor, and the other functions as the drain of the transistor.

[0221] A device isolation layer (132) is provided between two adjacent transistors so as to be embedded in the substrate (131).

[0222] An insulating layer (139) is provided covering the transistors (130a, 130b, and 130c), and a conductive layer (138) is provided on the insulating layer (139). The conductive layer (138) is electrically connected to one of a pair of low-resistance regions (133) through a conductive layer (137) provided to fill the opening of the insulating layer (139). An insulating layer (141) is provided covering the conductive layer (138), and a conductive layer (142) is provided on the insulating layer (141). The conductive layer (138) and the conductive layer (142) each function as wiring. An insulating layer (143) and an insulating layer (152) are provided covering the conductive layer (142).

[0223] The insulating layer (152) functions as a barrier layer that prevents impurities such as water and hydrogen from diffusing from the transistor (130a) side, transistor (130b) side, and transistor (130c) side to transistor (120a), transistor (120b), and transistor (120c), and prevents oxygen from escaping from the metal oxide layer (165) to the insulating layer (152) side. As the insulating layer (152), a film that is more difficult for hydrogen and oxygen to diffuse than a silicon oxide film may be used.

[0224] The transistors (120a, 120b, and 120c) each include a conductive layer (161), an insulating layer (163), an insulating layer (164), a metal oxide layer (165), a pair of conductive layers (166), an insulating layer (167), and a conductive layer (168), etc.

[0225] The metal oxide layer (165) includes a channel-forming region. The metal oxide layer (165) includes a first region that overlaps with one of a pair of conductive layers (166), a second region that overlaps with the other of a pair of conductive layers (166), and a third region between the first region and the second region.

[0226] A conductive layer (161) and an insulating layer (162) are provided on an insulating layer (152), and insulating layers (163 and 164) are provided covering the conductive layer (161) and the insulating layer (162). A metal oxide layer (165) is provided on the insulating layer (164). The conductive layer (161) functions as a gate electrode, and the insulating layers (163 and 164) each function as gate insulating layers. The conductive layer (161) overlaps with the metal oxide layer (165) through the insulating layers (163 and 164). It is preferable that the insulating layer (163) functions as a barrier layer, similar to the insulating layer (152). As for the insulating layer (164) in contact with the metal oxide layer (165), it is preferable to use an oxide insulating film such as a silicon oxide film.

[0227] Here, the upper surface of the conductive layer (161) is approximately the same height as the upper surface of the insulating layer (162). This allows the size of the transistors (120a and 120b) to be reduced.

[0228] A pair of conductive layers (166) are provided on the metal oxide layer (165) so as to be spaced apart from each other. The pair of conductive layers (166) function as a source and a drain. An insulating layer (181) is provided covering the metal oxide layer (165) and the pair of conductive layers (166), and an insulating layer (182) is provided on top of the insulating layer (181). An opening reaching the metal oxide layer (165) is provided in the insulating layer (181) and the insulating layer (182), and an insulating layer (167) and a conductive layer (168) are provided to fill this opening. The opening overlaps with the third region. The insulating layer (167) overlaps with the side of the insulating layers (181 and 182). The conductive layer (168) overlaps with the side of the insulating layers (181 and 182) through the insulating layer (167). The conductive layer (168) functions as a gate electrode, and the insulating layer (167) functions as a gate insulating layer. The conductive layer (168) overlaps with the metal oxide layer (165) through the insulating layer (167).

[0229] Here, the upper surface of the conductive layer (168) is approximately the same height as the upper surface of the insulating layer (182). This allows the size of the transistors (120a and 120b) to be reduced.

[0230] Insulating layers (183 and 185) are provided to cover the upper surfaces of insulating layers (182 and 167) and conductive layers (168). It is preferable that insulating layers (181 and 183) each function as barrier layers, such as insulating layer (152). If a pair of conductive layers (166) are covered with insulating layer (181), oxidation of the pair of conductive layers (166) due to oxygen contained in insulating layer (182) can be suppressed.

[0231] A plug electrically connected to one of a pair of conductive layers (166) and a conductive layer (189a) is provided to fill an opening provided in an insulating layer (181, 182, 183, and 185). The plug preferably comprises a conductive layer (184b) in contact with the side of the opening and the upper surface of one of the pair of conductive layers (166), and a conductive layer (184a) embedded inside the conductive layer (184b). Here, it is preferable to use a conductive material in which hydrogen and oxygen are difficult to diffuse for the conductive layer (184b).

[0232] A conductive layer (189a) and an insulating layer (186) are provided on an insulating layer (185), a conductive layer (189b) is provided on the conductive layer (189a), and an insulating layer (187) is provided on the insulating layer (186). It is preferable that the insulating layer (186) has a flattening function. Here, the upper surface of the conductive layer (189b) is approximately the same height as the upper surface of the insulating layer (187). An opening is provided in the insulating layers (187 and 186) that reaches the conductive layer (189a), and a conductive layer (189b) is provided to fill this opening. The conductive layer (189b) functions as a plug that electrically connects the conductive layer (189a) and the conductive layer (190a or 190c).

[0233] One of the pair of conductive layers (166) of the transistor (120a) is electrically connected to the conductive layer (190a) through the conductive layers (184a, 184b, 189a, and 189b).

[0234] Likewise, one of the pair of conductive layers (166) of the transistor (120b) is electrically connected to the conductive layer (190c) through the conductive layers (184a, 184b, 189a, and 189b).

[0235] One of the pair of conductive layers (166) of the transistor (120c) is electrically connected to the conductive layer (190e) through the conductive layers (184a, 184b, 189a, and 189b).

[0236] As for the insulating layer (187), for example, a film that is more difficult for one or both of hydrogen and oxygen to diffuse than a silicon oxide film may be used. It is preferable that the insulating layer (187) functions as a barrier layer that prevents impurities (e.g. hydrogen and water) from diffusing from the LED substrate (150C) to the transistor. It is preferable that the insulating layer (187) functions as a barrier layer that prevents impurities from diffusing from the circuit board (150D) to the LED substrate (150C).

[0237] The insulating layer (188) is a layer that is directly bonded to the insulating layer (104) included in the LED substrate (150C). It is preferable that the insulating layer (188) be formed using the same material as the insulating layer (104). It is preferable to use an oxide insulating film as the insulating layer (188). By directly bonding the oxide insulating films to each other, the bonding strength (bonding strength) can be increased. In addition, if one or both of the insulating layers (104 and 188) have a laminated structure, it is preferable that the layers in contact with each other (including the surface layer and the bonding surface) be formed using the same material.

[0238] The conductive layers (190a to 190e) and the conductive layer (190f) are layers that are directly adhered to the electrodes (117a to 117f) of the LED substrate (150C). It is preferable that the main components of the conductive layers (190a to 190f) and the main components of the electrodes (117a to 117f) are the same metal element, and it is more preferable that the conductive layers (190a to 190f) and the electrodes (117a to 117f) are formed using the same material. For the conductive layers (190a to 190f), for example, Cu, Al, Sn, Zn, W, Ag, Pt, or Au may be used. It is preferable to use Cu, Al, W, or Au for easy adhesion. In addition, if one or both of the conductive layers (190) and the electrodes (117) have a laminated structure, it is preferable that the layers in contact with each other (including the surface layer and the adhesive surface) are formed using the same material.

[0239] Additionally, the circuit board (150D) may include one or both of a reflective layer that reflects light from a light-emitting diode and a light-blocking layer that blocks this light.

[0240] As shown in FIG. 11, electrodes (117a, 117b, 117c, 117d, 117e, and 117f) provided on the LED substrate (150C) are each adhered to and electrically connected to conductive layers (190a, 190b, 190c, 190d, 190e, and 190f) provided on the circuit board (150D).

[0241] For example, by connecting the electrode (117a) and the conductive layer (190a) to each other, the transistor (120a) and the light-emitting diode (110a) can be electrically connected to each other. The electrode (117a) functions as a pixel electrode of the light-emitting diode (110a). The electrode (117b) and the conductive layer (190b) are connected to each other. The electrode (117b) functions as a common electrode of the light-emitting diode (110a).

[0242] Likewise, by connecting the electrode (117c) and the conductive layer (190c) to each other, the transistor (120b) and the light-emitting diode (110b) can be electrically connected to each other. The electrode (117c) functions as a pixel electrode of the light-emitting diode (110b). The electrode (117d) and the conductive layer (190d) are connected to each other. The electrode (117d) functions as a common electrode of the light-emitting diode (110b).

[0243] By connecting the electrode (117e) and the conductive layer (190e) to each other, the transistor (120c) and the light-emitting diode (110c) can be electrically connected to each other. The electrode (117e) functions as a pixel electrode of the light-emitting diode (110c). The electrode (117f) and the conductive layer (190f) are connected to each other. The electrode (117f) functions as a common electrode of the light-emitting diode (110c).

[0244] It is preferable that the main components of the electrodes (117a, 117b, 117c, 117d, 117e, and 117f) and the main components of the conductive layers (190a, 190b, 190c, 190d, 190e, and 190f) are the same metal element.

[0245] The insulating layer (104) provided on the LED substrate (150C) and the insulating layer (188) provided on the circuit board (150D) are directly bonded to each other. It is preferable that the insulating layers (104 and 188) be formed using the same main component or the same material.

[0246] A connection having mechanical strength can be obtained by the layers formed using the same material at the adhesive surface between the LED substrate (150C) and the circuit board (150D) coming into contact with each other.

[0247] After bonding the LED substrate (150C) and the circuit board (150D), the substrate (101) is peeled off.

[0248] There are no limitations on the method of peeling off the substrate (101), and, for example, as shown in FIG. 12, a method of irradiating a laser beam over the entire surface of the substrate (101) may be used. By doing so, the substrate (101) can be peeled off and the underlayer (109) can be exposed (Fig. 13).

[0249] A release layer may be provided between the substrate (101) and the light-emitting diodes (110a and 110b). For materials that can be used for the release layer, refer to Embodiment 1.

[0250] Then, a light-blocking layer (106), a color-converting layer (CCMR), a color-converting layer (CCMG), a coloring layer (CFR), a coloring layer (CFG), and a coloring layer (CFB) are formed on the lower film (109).

[0251] Specifically, a light-blocking layer (106) is formed between the red pixel and the blue pixel, and between the blue pixel and the green pixel.

[0252] A color conversion layer (CCMR) is formed in an area overlapping with the red pixel light-emitting diode (110a), and a coloring layer (CFR) is formed on the color conversion layer (CCMR). Similarly, a color conversion layer (CCMG) is formed in an area overlapping with the green pixel light-emitting diode (110c), and a coloring layer (CFG) is formed on the color conversion layer (CCMG). A coloring layer (CFB) is formed in an area overlapping with the blue pixel light-emitting diode (110b).

[0253] As a color conversion layer, it is preferable to use a phosphor or a quantum dot (QD). In particular, since quantum dots have a narrow peak in their emission spectrum, they can obtain emission with high color purity. This can improve the display quality of the display device.

[0254] The color conversion layer can be formed by droplet extrusion (e.g., inkjet method), coating, imprinting, or various printing methods (screen printing or offset printing). Additionally, a color conversion film such as a quantum dot film may be used.

[0255] For details regarding the quantum dots, refer to Embodiment 1.

[0256] A colored layer is a colored layer that transmits light within a specific wavelength range. For example, a color filter that transmits light within the wavelength ranges of red, green, blue, or yellow can be used. Examples of materials that can be used for the colored layer include metallic materials, resin materials, and resin materials containing pigments or dyes.

[0257] As described above, since the display device of the present embodiment can be manufactured by bonding a plurality of light-emitting diodes and a plurality of transistors at once, the manufacturing cost of the display device is reduced and the yield is improved. By combining a micro LED, a transistor using a metal oxide, and a transistor using a semiconductor substrate (in particular, a silicon substrate), high-speed operation of the circuit is possible, and a display device with reduced power consumption can be obtained.

[0258] In the display device of the present embodiment, a substrate on which a light-emitting diode is provided is peeled off, and a color conversion layer, a coloring layer, and a light-blocking layer are provided on the surface exposed by the peeling. Accordingly, the display quality of the display device can be improved.

[0259] In the display device of the present embodiment, since the size of the transistor can be reduced, it becomes easy to increase the resolution of the display device and to apply it to electronic devices having a relatively small display area.

[0260] This embodiment can be appropriately combined with any of the other embodiments.

[0261] (Embodiment 3)

[0262] In this embodiment, a transistor that can be used in a display device of one form of the present invention is described.

[0263] There are no specific limitations on the structure of the transistors in the display device. For example, planar transistors, staggered transistors, or inverse staggered transistors may be used. Top-gate transistors or bottom-gate transistors may also be used. Gate electrodes may be provided above and below the channel.

[0264] As a transistor for a display device, for example, a transistor containing a metal oxide in the channel forming region can be used. By doing so, a transistor with a very low off-state current can be obtained.

[0265] As a transistor for a display device, a transistor containing silicon in the channel forming region may be used. Examples of the above transistor include a transistor containing amorphous silicon, a transistor containing crystalline silicon (typically low-temperature polysilicon), and a transistor containing single-crystal silicon. For example, a combination of a transistor containing a metal oxide in the channel forming region and a transistor containing silicon in the channel forming region may be used.

[0266] In addition, as described in this specification and others, a transistor is a device having at least three terminals (gate, drain, and source). The transistor includes a region (hereinafter also referred to as a channel forming region) in which a channel is formed between a drain (drain terminal, drain region, or drain electrode) and a source (source terminal, source region, or source electrode), and current can flow between the source and the drain through the channel forming region. In addition, as described in this specification and others, a channel forming region refers to a region through which current mainly flows.

[0267] In addition, the functions of the source and drain may change, for example, when transistors of opposite polarity are used or when the direction of current flow changes during circuit operation. Therefore, in this specification and others, the terms "source" and "drain" may be interchangeable.

[0268] Furthermore, channel length refers to the distance between the source (source region or source electrode) and the drain (drain region or drain electrode) in the region where the semiconductor (or the part of the semiconductor through which current flows when the transistor is turned on) and the gate electrode overlap, for example, in a top view of a transistor, or in the channel forming region. In a single transistor, the channel length does not necessarily have to be the same in all regions. In other words, the channel length of a single transistor may not be fixed to a single value. Therefore, in this specification, any value, maximum value, minimum value, or average value in the channel forming region is defined as the channel length.

[0269] Channel width refers to the region where the semiconductor (or the part of the semiconductor through which current flows when the transistor is turned on) and the gate electrode overlap, for example in a top view of a transistor, or the length of the channel forming region perpendicular to the channel length direction in the channel forming region. In a single transistor, the channel width does not necessarily have to be the same in all regions. In other words, the channel width of a single transistor may not be fixed to a single value. Therefore, in this specification, any value, maximum value, minimum value, or average value in the channel forming region is defined as the channel width.

[0270] Furthermore, in the present specification and others, depending on the structure of the transistor, the channel width in the region where the channel is actually formed (hereinafter also referred to as "effective channel width") and the channel width shown in the top view of the transistor (hereinafter also referred to as "apparent channel width") may differ. For example, in a transistor having a gate electrode covering the side of the semiconductor, the effective channel width may be larger than the apparent channel width, and the influence thereof may not be negligible. As another example, in a miniaturized transistor having a gate electrode covering the side of the semiconductor, the proportion of the channel formation region formed on the side of the semiconductor may increase. In this case, the effective channel width is larger than the apparent channel width.

[0271] In such cases, it may be difficult to estimate the effective channel width through actual measurement. For instance, to estimate the effective channel width from design values, it is necessary to assume that the semiconductor shape is already known. Therefore, if the semiconductor shape is not precisely known, it is difficult to accurately measure the effective channel width.

[0272] In this specification, the simple term "channel width" may refer to the apparent channel width. The simple term "channel width" may also refer to the effective channel width. Additionally, values ​​such as channel length, channel width, effective channel width, and apparent channel width can be determined by analyzing a cross-sectional image obtained by a transmission electron microscope (TEM), etc.

[0273] Insulators, conductors, oxides, or semiconductors may be deposited by methods such as sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), or atomic layer deposition (ALD). In this specification and other contexts, the term "insulator" may be substituted with an insulating film or insulating layer. The term "conductor" may be substituted with a conductive film or conductive layer. The term "oxide" may be substituted with an oxide film or oxide layer. The term "semiconductor" may be substituted with a semiconductor film or semiconductor layer.

[0274] FIG. 14 (A) is a top view of a transistor (200). Also, for simplification, some components are not shown in FIG. 14 (A). FIG. 14 (B) is a cross-sectional view taken along the dotted line A1-A2 in FIG. 14 (A). FIG. 14 (B) can also be described as a cross-sectional view in the channel length direction of the transistor (200). FIG. 14 (C) is a cross-sectional view taken along the dotted line A3-A4 in FIG. 14 (A). FIG. 14 (C) can also be described as a cross-sectional view in the channel width direction of the transistor (200). FIG. 14 (D) is a cross-sectional view taken along the dotted line A5-A6 in FIG. 14 (A).

[0275] The semiconductor device shown in FIG. 14 (A) to (D) comprises an insulator (212) on a substrate (not shown in the drawing), an insulator (214) on the insulator (212), a transistor (200) on the insulator (214), an insulator (280) on the transistor (200), an insulator (282) on the insulator (280), an insulator (283) on the insulator (283), and an insulator (285) on the insulator (283). The insulators (212, 214, 280, 282, 283, and 285) each function as interlayer insulating films. The semiconductor device also includes a conductor (240) (conductor (240a) and conductor (240b)) that is electrically connected to the transistor (200) and functions as a plug. Additionally, an insulator (241) (insulator (241a) and insulator (241b)) is provided in contact with the side of the conductor (240) that functions as a plug. Above the insulator (285) and the conductor (240), a conductor (246) (conductor (246a) and conductor (246b)) is provided that is electrically connected to the conductor (240) and functions as wiring.

[0276] An insulator (241a) is provided in contact with the inner wall of an opening formed in the insulators (280, 282, 283, and 285), a first conductor of a conductor (240a) is provided in contact with the side of the insulator (241a), and a second conductor of a conductor (240a) is provided inside the first conductor. An insulator (241b) is provided in contact with the inner wall of an opening formed in the insulators (280, 282, 283, and 285), a first conductor of a conductor (240b) is provided in contact with the side of the insulator (241b), and a second conductor of a conductor (240b) is provided inside the first conductor. In the area overlapping with the conductor (246), the height of the upper surface of the conductor (240) and the upper surface of the insulator (285) can be made approximately the same. In the transistor (200), a first conductor and a second conductor are stacked as conductors (240), but the present invention is not limited thereto. For example, the conductor (240) may have a single-layer structure or a stacked structure of three or more layers. When a stacked structure is adopted, the layers may be distinguished by numbers corresponding to the order of formation.

[0277] [Transistor (200)]

[0278] As shown in FIG. 14 (A) to (D), the transistor (200) comprises an insulator (216) on an insulator (214), a conductor (205) (conductor (205a), conductor (205b), and conductor (205c)) provided to be embedded in the insulator (216), an insulator (222) on the insulator (216) and conductor (205), an insulator (224) on the insulator (222), an oxide (230a) on the insulator (224), an oxide (230b) on the oxide (230a), an oxide (243) (oxide (243a) and oxide (243b)) on the oxide (230b), a conductor (242a) on the oxide (243a), an insulator (271a) on the conductor (242a), a conductor (242b) on the oxide (243b), and a conductor (242b) on the insulator (242b). It includes an insulator (271b), an insulator (250) (insulator (250a) and insulator (250b)) on an oxide (230b), a conductor (260) (conductor (260a) and conductor (260b)) provided on the insulator (250) and overlapping with a portion of the oxide (230b), and an insulator (222), an insulator (224), an oxide (230a), an oxide (230b), an oxide (243a), an oxide (243b), a conductor (242a), a conductor (242b), an insulator (271a), and an insulator (275) provided covering the insulator (271b).

[0279] In the following, oxide (230a) and oxide (230b) may be collectively referred to as oxide (230). Conductor (242a) and conductor (242b) may be collectively referred to as conductor (242). Insulator (271a) and insulator (271b) may be collectively referred to as insulator (271).

[0280] The insulators (280 and 275) are provided with an opening reaching the oxide (230b). An insulator (250) and a conductor (260) are provided within the opening. Additionally, in the channel length direction of the transistor (200), a conductor (260) and an insulator (250) are provided between the insulator (271a), the conductor (242a), and the oxide (243a), and between the insulator (271b), the conductor (242b), and the oxide (243b). The insulator (250) includes a region in contact with the side of the conductor (260) and a region in contact with the bottom of the conductor (260).

[0281] The oxide (230) preferably comprises an oxide (230a) provided on the insulator (224) and an oxide (230b) provided on the oxide (230a). If the oxide (230a) is provided below the oxide (230b), the diffusion of impurities from the component formed below the oxide (230a) into the oxide (230b) can be suppressed.

[0282] The oxide (230) of the transistor (200) has a structure in which two layers of oxide (230a) and oxide (230b) are stacked, but the present invention is not limited to this structure. For example, the oxide (230) may have a single-layer structure of oxide (230b) or a stacked structure of three or more layers, and the oxide (230a) and oxide (230b) may each have a stacked structure.

[0283] The conductor (260) functions as a first gate (also called a top gate) electrode, and the conductor (205) functions as a second gate (also called a back gate) electrode. The insulator (250) functions as a first gate insulating film, and the insulator (224) and insulator (222) function as second gate insulating films. The conductor (242a) functions as one of the source electrode and the drain electrode, and the conductor (242b) functions as the other of the source electrode and the drain electrode. In the oxide (230), the region overlapping with the conductor (260) functions as at least a portion of the channel forming region.

[0284] The region overlapping with the conductor (242a) in the oxide (230b) includes one of the source region and the drain region, and the region overlapping with the conductor (242b) in the oxide (230b) includes the other of the source region and the drain region. The region sandwiched between the source region and the drain region in the oxide (230b) includes a channel forming region (the region indicated by the diagonal line in (B) of FIG. 14).

[0285] Since the channel-forming region has less oxygen deficiency or a lower impurity concentration than the source and drain regions, it has a lower carrier concentration and higher resistance. Here, the carrier concentration in the channel-forming region is 1×10 18 cm -3 The following is preferable, and 1X10 17 cm -3 Less than is more desirable, and 1X10 16 cm -3 Less than is more desirable, and 1X10 13 cm -3 Less than is more desirable, and 1X10 12 cm -3 It is even more desirable for it to be less than. In addition, the lower limit of the carrier concentration in the channel-forming region is not specifically limited, for example, 1×10 -9 cm -3 It can be done as.

[0286] In the example described above, a channel-forming region, a source region, and a drain region are formed in the oxide (230b), but the present invention is not limited thereto. For example, a channel-forming region, a source region, and a drain region may also be formed in the oxide (230a).

[0287] In the transistor (200), it is preferable that the oxide (230) (oxide (230a and 230b)) including the channel forming region be formed using a metal oxide (hereinafter referred to as an oxide semiconductor) that functions as a semiconductor.

[0288] It is preferable that the metal oxide functioning as a semiconductor has a band gap of 2 eV or more, preferably 2.5 eV or more. By using such a metal oxide with a wide band gap, the off-state current of the transistor can be reduced.

[0289] For example, as an oxide (230), indium, element M , and In- including zinc M - Using metal oxides such as Zn oxide, and elements M It is one or more selected from aluminum, gallium, yttrium, tin, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium. Alternatively, In-Ga oxide, In-Zn oxide, or indium oxide may be used as the oxide (230).

[0290] Here, the element in the metal oxide used as the oxide (230b) M The atomic number ratio of In to is the element in the metal oxide used as the oxide (230a). M It is desirable that the ratio of the number of atoms of In to is higher than that of .

[0291] Specifically, as an oxide (230a), the atomic ratio is In: M :Zn=1:3:4 or its vicinity, or the atomic ratio In: M It is preferable to use a metal oxide with an atomic ratio of :Zn=1:1:0.5 or a similar ratio. As for the oxide (230b), the atomic ratio is In: M :Zn=1:1:1 or its vicinity, or the atomic ratio is In: M It is preferable to use metal oxides with a Zn ratio of 4:2:3 or a similar range. Additionally, the nearby atomic ratios contain ±30% of the intended atomic ratio. Element M It is preferable to use gallium as such.

[0292] When depositing metal oxides by sputtering, the above-mentioned atomic ratio is not limited to the atomic ratio of the deposited metal oxide, but may also be the atomic ratio of the sputtering target used for depositing the metal oxide.

[0293] If an oxide (230a) is provided below the oxide (230b) in the manner described above, the diffusion of impurities and oxygen from the component formed below the oxide (230a) into the oxide (230b) can be suppressed.

[0294] In addition, by including a common element other than oxygen (as a main component) in oxide (230a) and oxide (230b), the defect level density at the interface between oxide (230a) and oxide (230b) can be lowered. Since the defect level density at the interface between oxide (230a) and oxide (230b) can be lowered, the influence of interfacial scattering on carrier conduction can be reduced, and a high on-state current can be obtained.

[0295] It is preferable that the oxides (230a and 230b) each have crystallinity. In particular, it is preferable to use a CAAC-OS (c-axis-aligned crystalline oxide semiconductor) as the oxide (230b).

[0296] CAAC-OS has high crystallinity and impurities or defects (oxygen vacancies (V)). O It is a metal oxide having a dense structure with a small amount of ) etc. In particular, after the formation of the metal oxide, at a temperature (e.g., 400°C) at which the metal oxide does not become polycrystalline. to 600 By performing a heat treatment, a CAAC-OS with a more crystallin and dense structure can be obtained. By increasing the density of the CAAC-OS in this way, the diffusion of impurities or oxygen within the CAAC-OS can be further reduced.

[0297] On the other hand, in CAAC-OS, since it is difficult to observe distinct grain boundaries, a decrease in electron mobility caused by grain boundaries is unlikely to occur. Therefore, metal oxides containing CAAC-OS are physically stable. Consequently, metal oxides containing CAAC-OS are heat-resistant and highly reliable.

[0298] It is preferable that at least one of the insulators (212, 214, 271, 275, 282, and 283) functions as a barrier insulating film that suppresses the diffusion of impurities, such as water and hydrogen, from the substrate side or from the top of the transistor (200) to the transistor (200). Accordingly, it is preferable that at least one of the insulators (212, 214, 271, 275, 282, and 283) is formed using an insulating material that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitric oxide molecules (e.g., N2O, NO, and NO2), and copper atoms, i.e., an insulating material that is difficult for said impurities to penetrate. Alternatively, it is preferable to use an insulating material that has the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules, etc.), i.e., an insulating material that is difficult for said oxygen to penetrate.

[0299] In addition, as defined herein, a barrier insulating film refers to an insulating film having barrier properties. As defined herein, barrier properties refer to a function of inhibiting the diffusion of a specific substance (also referred to as a function that does not easily allow this substance to pass through). Alternatively, as defined herein, barrier properties refer to a function of capturing and fixing a specific substance (also referred to as gettering).

[0300] For the insulators (212, 214, 271, 275, 282, and 283), for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon nitride oxide may be used. For example, it is preferable to use silicon nitride, which has high hydrogen barrier properties, for the insulators (212, 275, and 283). For example, it is preferable to use aluminum oxide or magnesium oxide, which has excellent hydrogen trapping and fixing capabilities, for the insulators (214, 271, and 282). By doing so, the diffusion of impurities such as water and hydrogen from the substrate side to the transistor (200) side through the insulators (212 and 214) can be suppressed. Additionally, the diffusion of impurities such as water and hydrogen from an interlayer insulating film, etc., disposed on the outside of the insulator (283) to the transistor (200) side can be suppressed. In addition, oxygen contained in the insulator (224), etc., can be suppressed from diffusing to the substrate side through the insulator (212 and 214). Oxygen contained in the insulator (280), etc., can be suppressed from diffusing to the components on the transistor (200) through the insulator (282), etc. In this way, it is preferable to surround the transistor (200) with insulators (212, 214, 271, 275, 282, and 283) having the function of suppressing the diffusion of oxygen and impurities such as water and hydrogen.

[0301] Here, it is preferable to use oxides having an amorphous structure as insulators (212, 214, 271, 275, 282, and 283). For example, AlO x ( x is any number greater than 0) or MgO y ( yIt is preferable to use a metal oxide such as (an arbitrary number greater than 0). In such metal oxides having an amorphous structure, oxygen atoms may have dangling bonds, and the metal oxide may have the property of capturing or fixing hydrogen through these dangling bonds. By using such a metal oxide having an amorphous structure as a component of the transistor (200) or providing it near the transistor (200), hydrogen contained in the transistor (200) or hydrogen in the vicinity of the transistor (200) can be captured or fixed. In particular, it is preferable to capture or fix hydrogen contained in the channel forming region of the transistor (200). By using a metal oxide having an amorphous structure as a component of the transistor (200) or providing it near the transistor (200), a transistor (200) and a semiconductor device having good characteristics and high reliability can be manufactured.

[0302] The insulators (212, 214, 271, 275, 282, and 283) preferably have an amorphous structure, but they may include regions having a polycrystalline structure. Alternatively, the insulators (212, 214, 271, 275, 282, and 283) may have a multilayer structure in which a layer having an amorphous structure and a layer having a polycrystalline structure are stacked. For example, a stacked structure in which a layer having a polycrystalline structure is formed on a layer having an amorphous structure may be adopted.

[0303] The insulators (212, 214, 271, 275, 282, and 283) can be deposited, for example, by sputtering. Since the sputtering method does not require the use of hydrogen as a deposition gas, the hydrogen concentration of the insulators (212, 214, 271, 275, 282, and 283) can be reduced. In addition, the deposition method is not limited to the sputtering method, and the CVD method, MBE method, PLD method, or ALD method can be appropriately used.

[0304] It is preferable that the dielectric constant of the insulators (216, 280, and 285) be lower than the dielectric constant of the insulator (214). By using a material with a low dielectric constant for the interlayer insulating film, parasitic capacitance between the wires can be reduced. For example, silicon oxide, silicon nitride, silicon nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, or porous silicon oxide are appropriately used for the insulators (216, 280, and 285).

[0305] A conductor (205) is provided to overlap with an oxide (230) and a conductor (260). Here, it is preferable that the conductor (205) be provided to fill an opening formed in an insulator (216).

[0306] The conductor (205) includes conductors (205a, 205b, and 205c). Conductor (205a) is provided in contact with the bottom surface and side wall of the opening. Conductor (205b) is provided to be embedded in a recess formed in the conductor (205a). Here, the height of the upper surface of the conductor (205b) is lower than the height of the upper surfaces of the conductor (205a) and the insulator (216). Conductor (205c) is provided in contact with the upper surface of the conductor (205b) and the side surface of the conductor (205a). Here, the upper surface of the conductor (205c) is approximately the same height as the upper surfaces of the conductor (205a) and the insulator (216). That is, the conductor (205b) is surrounded by the conductor (205a) and the conductor (205c).

[0307] For the conductors (205a and 205c), it is preferable to use a conductive material that can be used for the conductor (260a) described later. For the conductor (205b), it is preferable to use a conductive material that can be used for the conductor (260b) described later. The conductor (205) of the transistor (200) has a stacked structure of conductors (205a, 205b, and 205c), but the present invention is not limited to this structure. For example, the conductor (205) may have a single-layer structure or a stacked structure of two layers or four or more layers.

[0308] The insulators (222 and 224) function as gate insulating films.

[0309] It is preferable that the insulator (222) has a function of inhibiting the diffusion of hydrogen (e.g., at least one of hydrogen atoms and hydrogen molecules). Additionally, it is preferable that the insulator (222) has a function of inhibiting the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules). For example, it is preferable that the insulator (222) has a function of inhibiting the diffusion of hydrogen and / or oxygen more than the insulator (224).

[0310] As the insulator (222), it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium, which are insulating materials. As the insulator, it is preferable to use aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate), etc. As the insulator (222), a barrier insulating film that can be used as an insulator (214), etc. may be used.

[0311] Silicon oxide or silicon nitride, etc., may be appropriately used for the insulator (224). By providing an insulator (224) containing oxygen in contact with the oxide (230), the oxygen deficiency within the oxide (230) can be reduced, thereby improving the reliability of the transistor (200). It is preferable that the insulator (224) be processed into an island shape so as to overlap with the oxide (230a). In this case, the insulator (275) is in contact with the side of the insulator (224) and the top surface of the insulator (222). By doing so, the insulator (224) and the insulator (280) can be separated from each other by the insulator (275), thereby reducing the diffusion of oxygen contained in the insulator (280) into the insulator (224), and thus preventing the amount of oxygen within the insulator (224) from becoming excessive.

[0312] Additionally, the insulators (222 and 224) may each have a stacked structure of two or more layers. In this case, the stacking does not necessarily have to be formed of the same material and may be formed of different materials. Also, in Fig. 14 (B), etc., a structure is shown in which the insulator (224) is formed in an island shape so as to overlap with the oxide (230a), but the present invention is not limited to this structure. If the amount of oxygen contained in the insulator (224) can be appropriately adjusted, a structure in which the insulator (224) is not patterned in the same way as the insulator (222) may be adopted.

[0313] Oxides (243a and 243b) are provided on the oxide (230b). The oxides (243a and 243b) are provided separated from each other by interposing a conductor (260). It is preferable that the oxide (243) (oxides (243a and 243b)) has the function of inhibiting oxygen permeation. It is preferable to provide an oxide (243) having the function of inhibiting oxygen permeation between the oxide (230b) and the conductor (242) which functions as a source electrode or drain electrode, so that the electrical resistance between the oxide (230b) and the conductor (242) is reduced. If the electrical resistance between the oxide (230b) and the conductor (242) can be sufficiently reduced, the oxide (243) does not need to be provided.

[0314] Element as oxide (243) M Metal oxides containing may also be used. In particular, the element M As such, it is preferable to use aluminum, gallium, yttrium, or tin. Element in oxide (243) M The concentration of the element in the oxide (230b) M It is preferable that the concentration be higher than that of . Alternatively, gallium oxide may be used as the oxide (243). In- as the oxide (243) M Metal oxides such as Zn oxide may also be used. Specifically, the element for In in the metal oxide used as the oxide (243) M The atomic ratio of the element for In in the metal oxide used as the oxide (230b) M It is preferable that the atomic ratio is higher than that of the oxide (243). The thickness of the oxide (243) is preferably 0.5 nm or more and 5 nm or less, more preferably 1 nm or more and 3 nm or less, and even more preferably 1 nm or more and 2 nm or less.

[0315] It is preferable that the conductor (242a) be provided in contact with the upper surface of the oxide (243a), and the conductor (242b) be provided in contact with the upper surface of the oxide (243b). The conductor (242a) and the conductor (242b) function as the source electrode and the drain electrode of the transistor (200).

[0316] For the conductor (242) (conductor (242a and 242b)), it is preferable to use, for example, a nitride containing tantalum, a nitride containing titanium, a nitride containing molybdenum, a nitride containing tungsten, a nitride containing tantalum and aluminum, or a nitride containing titanium and aluminum. In one embodiment of the present invention, a nitride containing tantalum is particularly preferred. As other examples, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, or an oxide containing lanthanum and nickel may be used. These materials are preferred because they are conductive materials that do not oxidize easily or materials that maintain conductivity even when absorbing oxygen.

[0317] It is preferable that no curved surface be formed between the side and top surfaces of the conductor (242). If there is no curved surface, the cross-sectional area of ​​the conductor (242) in the channel width direction can be increased as shown in (D) of FIG. 14. By doing so, the conductivity of the conductor (242) is increased, thereby increasing the on-state current of the transistor (200).

[0318] An insulator (271a) is provided in contact with the upper surface of a conductor (242a), and an insulator (271b) is provided in contact with the upper surface of a conductor (242b).

[0319] The insulator (275) is provided in contact with the upper surface of the insulator (222), the side of the insulator (224), the side of the oxide (230a), the side of the oxide (230b), the side of the oxide (243), the side of the conductor (242), and the upper surface and side of the insulator (271). An opening is provided in the area where the insulator (250) and the conductor (260) are provided in the insulator (275).

[0320] By providing an insulator (214, 271, and 275) having the function of capturing impurities such as hydrogen in a region sandwiched between an insulator (212) and an insulator (283), impurities such as hydrogen contained in the insulator (224) or an insulator (216), etc., can be captured, and the amount of hydrogen in the region can be maintained constant. In this case, it is preferable that the insulator (214, 271, and 275) include aluminum oxide having an amorphous structure.

[0321] The insulator (250) comprises an insulator (250a) and an insulator (250b) on top of the insulator (250a) and functions as a gate insulating film. It is preferable that the insulator (250a) be provided in contact with the upper surface of the oxide (230b), the side surface of the oxide (243), the side surface of the conductor (242), the side surface of the insulator (271), the side surface of the insulator (275), and the side surface of the insulator (280). The thickness of the insulator (250) is preferably 1 nm or more and 20 nm or less.

[0322] Insulator (250a) may use silicon oxide, silicon nitride, silicon nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, or porous silicon oxide. In particular, silicon oxide and silicon nitride are preferred because they are thermally stable. In the insulator (250a), it is preferable that the concentration of impurities such as water and hydrogen be reduced, as in the insulator (224).

[0323] It is preferable that the insulator (250a) be formed using an insulator from which oxygen is released upon heating, and the insulator (250b) be formed using an insulator having a function to inhibit the diffusion of oxygen. By having this structure, the diffusion of oxygen contained in the insulator (250a) into the conductor (260) can be inhibited. That is, the reduction of the amount of oxygen supplied to the oxide (230) can be inhibited. In addition, the oxidation of the conductor (260) caused by the oxygen contained in the insulator (250a) can be inhibited. For example, the insulator (250b) can be formed using the same material as that used for the insulator (222).

[0324] Specifically, the insulator (250b) may use a metal oxide or an oxide (230) that can be used as a metal oxide containing one or more of hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium. In particular, it is preferable to use an insulator containing an oxide of either or both of aluminum and hafnium. As the insulator, it is preferable to use aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate), etc. The thickness of the insulator (250b) is preferably 0.5 nm or more and 3.0 nm or less, and more preferably 1.0 nm or more and 1.5 nm or less.

[0325] Figures 14 (B) and (C) show that the insulator (250) has a two-layer stacked structure, but the present invention is not limited thereto. The insulator (250) may have a single-layer structure or a stacked structure of three or more layers.

[0326] A conductor (260) is provided on an insulator (250b) and functions as a first gate electrode of a transistor (200). The conductor (260) preferably comprises a conductor (260a) and a conductor (260b) on top of the conductor (260a). For example, it is preferable that the conductor (260a) be positioned to cover the bottom and side surfaces of the conductor (260b). As shown in FIG. 14 (B) and (C), the top surface of the conductor (260) is approximately the same height as the top surface of the insulator (250). FIG. 14 (B) and (C) show that the conductor (260) has a two-layer structure of a conductor (260a) and a conductor (260b), but the conductor (260) may be a single-layer structure or a stacked structure of three or more layers.

[0327] The conductor (260a) is preferably formed using a conductive material having the function of inhibiting the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitric oxide molecules, and copper atoms. Alternatively, the conductor (260a) is preferably formed using a conductive material having the function of inhibiting the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules).

[0328] If the conductor (260a) has a function of inhibiting the diffusion of oxygen, it is possible to prevent the conductor (260b) from being oxidized due to oxygen in the insulator (250) and thereby reducing the conductivity of the conductor (260b). As a conductive material having a function of inhibiting the diffusion of oxygen, it is preferable to use, for example, titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, or ruthenium oxide.

[0329] Since the conductor (260) also functions as wiring, it is desirable that it be a highly conductive conductor. For example, the conductor (260b) may use a conductive material containing tungsten, copper, or aluminum as a main component. The conductor (260b) may have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the conductive material.

[0330] In the transistor (200), the conductor (260) is formed self-aligned to fill an opening formed in the insulator (280), etc. In this way, the conductor (260) can be reliably provided without alignment in the region between the conductor (242a) and the conductor (242b).

[0331] As shown in (C) of FIG. 14, in the channel width direction of the transistor (200), when based on the height of the bottom surface of the insulator (222), it is preferable that the height of the bottom surface of the region of the conductor (260) that does not overlap with the oxide (230b) is lower than the height of the bottom surface of the oxide (230b). When the conductor (260), which functions as a gate electrode, covers the side and top surfaces of the channel forming region of the oxide (230b) with the insulator (250) or the like, it becomes easier to apply the electric field of the conductor (260) to the entire channel forming region of the oxide (230b). Therefore, the on-state current of the transistor (200) can be increased, and the frequency characteristics can be improved. Based on the height of the bottom surface of the insulator (222), the distance between the bottom surface of the conductor (260) and the bottom surface of the oxide (230b) in the region where the conductor (260) does not overlap with the oxide (230a and 230b) is 0 nm or more and 100 nm or less, preferably 3 nm or more and 50 nm or less, more preferably 5 nm or more and 20 nm or less.

[0332] An insulator (280) is provided over an insulator (275), and an opening is formed in the area where the insulator (250) and the conductor (260) are provided. The upper surface of the insulator (280) may be flattened. In this case, it is preferable that the upper surface of the insulator (280) be approximately the same height as the upper surface of the insulator (250) and the upper surface of the conductor (260).

[0333] An insulator (282) is provided in contact with the upper surface of the insulator (280), the upper surface of the insulator (250), and the upper surface of the conductor (260). It is preferable that the insulator (282) functions as a barrier insulating film that suppresses the diffusion of impurities such as water and hydrogen from the top into the insulator (280), and it is also preferable that it has a function of capturing impurities such as hydrogen. It is also preferable that the insulator (282) functions as a barrier insulating film that suppresses the permeation of oxygen. For example, an insulator such as aluminum oxide can be used as the insulator (282). By providing an insulator (282) that has a function of capturing impurities such as hydrogen in contact with the insulator (280) in the area sandwiched between the insulator (212) and the insulator (283), impurities such as hydrogen contained in the insulator (280) can be captured, and the amount of hydrogen in the said area can be maintained at a constant level. In particular, using aluminum oxide having an amorphous structure as an insulator (282) is preferable because it can more effectively capture or bind hydrogen. By doing so, a transistor (200) and a semiconductor device with good characteristics and high reliability can be manufactured.

[0334] The conductors (240a and 240b) are preferably formed using a conductive material containing tungsten, copper, or aluminum as a main component. The conductors (240a and 240b) may have a laminated structure. If the conductor (240) has a laminated structure, the conductor in contact with the insulator (241) is preferably formed using a conductive material that has the function of suppressing the permeation of impurities such as water and hydrogen. For example, any of the above conductive materials that can be used for the conductor (260a) may be used.

[0335] As for the insulators (241a and 241b), it is preferable to use insulators such as silicon nitride, aluminum oxide, or silicon nitride oxide. Since the insulators (241a and 241b) are provided in contact with the insulators (283, 282, and 271), impurities such as water and hydrogen contained in the insulators (280), etc., can be prevented from entering the oxide (230) through the conductors (240a and 240b).

[0336] A conductor (246) (conductors (246a and 246b)) that functions as wiring in contact with the upper surface of the conductors (240a and 240b) may be provided. The conductor (246) is preferably formed using a conductive material containing tungsten, copper, or aluminum as a main component. The conductor may have a laminated structure, for example, a laminate of titanium or titanium nitride and the conductive material. Additionally, the conductor may be formed to fill an opening in the insulator.

[0337] In the manner described above, a semiconductor device having good electrical characteristics can be provided. A semiconductor device with high reliability can also be provided. A semiconductor device capable of miniaturization or high integration can be provided. Alternatively, a semiconductor device with low power consumption can be provided.

[0338] [Metal Oxide]

[0339] Next, we will explain metal oxides (also called oxide semiconductors) that can be used in transistors.

[0340] It is preferable that the metal oxide contains at least indium or zinc. In particular, it is preferable that it contains indium and zinc. It is also preferable that it contains aluminum, gallium, yttrium, or tin, etc. 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, and cobalt, etc.

[0341] Metal oxides can be formed using CVD methods such as sputtering, MOCVD (metal organic chemical vapor deposition), or ALD.

[0342] Classification of Crystal Structures

[0343] Examples of crystal structures of oxide semiconductors include amorphous (including completely amorphous structures), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single-crystal, and polycrystalline structures.

[0344] The crystal structure of a film or substrate can be analyzed using X-ray diffraction (XRD) spectra. For example, evaluation can be performed using XRD spectra obtained by grazing-incidence XRD (GIXD) measurements. The GIXD method is also known as the thin film method or the Seemann-Bohlin method.

[0345] For example, the peaks in the XRD spectrum of a quartz glass substrate have a left-right symmetrical shape. On the other hand, the peaks in the XRD spectrum of an IGZO film with a crystalline structure have a left-right asymmetrical shape. Left-right asymmetrical peaks indicate the presence of crystals within the film or substrate. In other words, if the peaks in the XRD spectrum are not left-right symmetrical, the crystalline structure of the film or substrate cannot be considered "amorphous."

[0346] The crystal structure of a film or substrate can be analyzed using diffraction patterns obtained by nanobeam electron diffraction (NBED), also known as nanobeam electron diffraction patterns. For example, a halo pattern is observed in the diffraction pattern of a quartz glass substrate, indicating that the quartz glass substrate is in an amorphous state. Furthermore, a spot-shaped pattern is observed in the diffraction pattern of an IGZO film formed at room temperature, rather than a halo pattern. Therefore, it is presumed that the IGZO film formed at room temperature is in an intermediate state, neither crystalline nor amorphous, and it cannot be concluded that the IGZO film is in an amorphous state.

[0347] Structure of Oxide Semiconductors

[0348] When classified in terms of structure, oxide semiconductors are sometimes classified differently from those described above. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the CAAC-OS and nc-OS described above. Other examples of non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, a-like OS (amorphous-like oxide semiconductor), and amorphous oxide semiconductors.

[0349] Here, the aforementioned CAAC-OS, nc-OS, and a-like OS are explained in detail.

[0350] [[CAAC-OS]]

[0351] CAAC-OS is an oxide semiconductor having multiple crystal regions, each having a c-axis orientation in a specific direction. Furthermore, the specific direction refers to the thickness direction of the CAAC-OS film, the normal direction of the plane where the CAAC-OS film is formed, or the normal direction of the surface of the CAAC-OS film. A crystal region refers to a region having a periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystal region also refers to a region where the lattice arrangement is regular. CAAC-OS has a region where multiple crystal regions are connected in the direction of the ab plane, and said region may have deformation. Furthermore, deformation refers to the part where the direction of the lattice arrangement changes between a region with a regular lattice arrangement and another region with a regular lattice arrangement within the region where multiple crystal regions are connected. In other words, CAAC-OS is an oxide semiconductor that has a c-axis orientation and does not have a clear orientation in the direction of the ab plane.

[0352] In addition, each of the above plurality of crystal regions is formed by one or more microcrystalline crystals (each having a maximum diameter of less than 10 nm). When a crystal region is formed by a single microcrystalline crystal, the maximum diameter of this crystal region is less than 10 nm. When a crystal region is formed by a plurality of microcrystalline crystals, the size of this crystal region may be several tens of nm.

[0353] Also In- M -Zn oxide (element) M In one or more of aluminum, gallium, yttrium, tin, and titanium, etc., CAAC-OS comprises a layer containing indium (In) and oxygen (hereinafter, the In layer), and an element M A layer containing , zinc (Zn), and oxygen (hereinafter, ( M It tends to have a layered crystal structure (also called a layered structure) in which layers of indium (Zn) are stacked. Indium and element M can be substituted for each other. Therefore ( M Indium is sometimes contained in the Zn layer. Additionally, the In layer contains elementsM There are cases where this is included. In addition, Zn may be included in the In layer. Such layered structures are observed as a lattice structure, for example, in high-resolution TEM images.

[0354] For example, when structural analysis is performed on a CAAC-OS film using an out-of-plane XRD measurement with an XRD device using a θ / 2θ scan, a peak indicating c-axis orientation is detected at 2θ = 31° or nearby. In addition, the position of the peak indicating c-axis orientation (value of 2θ) may vary depending on the type or composition of the metal element included in the CAAC-OS.

[0355] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. Furthermore, some spots and others are symmetric with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0356] When observing the crystal region from the aforementioned specific direction, the lattice arrangement within the crystal region is fundamentally a hexagonal lattice; however, the unit cell is not always a regular hexagon and may be non-regular hexagonal. The aforementioned deformation may include pentagonal and heptagonal lattice arrangements. Furthermore, in CAAC-OS, clear grain boundaries cannot be observed even near deformation. In other words, the formation of grain boundaries is suppressed by the deformation of the lattice arrangement. This is thought to be because CAAC-OS allows for deformation due to factors such as the low density of oxygen atoms in the ab plane direction and changes in interatomic bond distances caused by the substitution of metal atoms.

[0357] Crystal structures in which distinct grain boundaries are observed are so-called polycrystalline structures. Since grain boundaries act as recombination centers and trap carriers, there is a high likelihood that, for example, the on-state current and field-effect mobility of a transistor will be degraded. Therefore, CAAC-OS, in which distinct grain boundaries are not observed, is one of the crystalline oxides having a crystal structure suitable for the semiconductor layer of a transistor. Furthermore, it is desirable to include Zn to form CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the occurrence of grain boundaries more effectively compared to In oxide.

[0358] CAAC-OS is an oxide semiconductor with high crystallinity in which distinct grain boundaries are not observed. Therefore, in CAAC-OS, a decrease in electron mobility caused by grain boundaries is unlikely to occur. The crystallinity of oxide semiconductors can be degraded by the intrusion of impurities or the formation of defects. This implies that CAAC-OS can be described as an oxide semiconductor with low levels of impurities and defects (e.g., oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS are physically stable. Therefore, oxide semiconductors containing CAAC-OS possess heat resistance and high reliability. Furthermore, CAAC-OS is stable under high temperatures (so-called thermal budget) during the fabrication process. Thus, using CAAC-OS in OS transistors allows for greater flexibility in the fabrication process.

[0359] [[nc-OS]]

[0360] In nc-OS, minute regions (e.g., regions with a size of 1 nm or more and 10 nm or less, particularly regions with a size of 1 nm or more and 3 nm or less) have a periodic atomic arrangement. In other words, nc-OS contains microcrystals. Furthermore, since the size of the microcrystals is, for example, 1 nm or more and 10 nm or less, particularly 1 nm or more and 3 nm or less, these microcrystals are also referred to as nanocrystals. In nc-OS, there is no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the entire film. Consequently, depending on the analysis method, nc-OS may not be distinguishable from α-like OS or amorphous oxide semiconductors. When structural analysis is performed on an nc-OS film using, for example, out-of-plane XRD measurements with an XRD device using θ / 2θ scans, no peaks indicating crystallinity are observed. Additionally, a halo pattern appears in the limited-field electron diffraction pattern of the nc-OS film obtained using an electron beam with a probe diameter larger than the diameter of the nanocrystals (e.g., 50 nm or more). Meanwhile, in the nanobeam electron diffraction pattern of an nc-OS film obtained using an electron beam having a probe diameter that is close to or smaller than the diameter of the nanocrystal (e.g., 1 nm or more and 30 nm or less), multiple spots may be observed within a ring-shaped region centered on a direct spot.

[0361] [[a-like OS]]

[0362] a-like OS is an oxide semiconductor with a structure intermediate between nc-OS and amorphous oxide semiconductors. a-like OS contains voids or low-density regions. In other words, a-like OS has lower crystallinity than nc-OS and CAAC-OS. Additionally, a-like OS has a higher hydrogen concentration than nc-OS and CAAC-OS.

[0363] Structure of Oxide Semiconductors

[0364] Next, the above-mentioned CAC-OS will be explained in detail. Furthermore, CAC-OS relates to the material composition.

[0365] [[CAC-OS]]

[0366] CAC-OS has a composition in which elements contained in, for example, metal oxides are unevenly distributed. Each material containing unevenly distributed elements has a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or less, or a size in the vicinity thereof. Furthermore, in the following description regarding metal oxides, a state in which one or more types of metal elements are unevenly distributed and regions containing these metal elements are mixed is referred to as a mosaic pattern or a patch pattern. Each of the said regions has a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or less, or a size in the vicinity thereof.

[0367] In addition, CAC-OS has a configuration in which the material is separated into a first region and a second region to form a mosaic pattern, and the first region is distributed within the film. Hereinafter, this configuration is also referred to as a cloud-like configuration. That is, CAC-OS is a composite metal oxide having a configuration in which the first region and the second region are mixed.

[0368] Here, the atomic number ratios of In, Ga, and Zn to the metal elements included in the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in In-Ga-Zn oxide, the first region has [In] higher than [In] in the composition of the CAC-OS film. Also, in the CAC-OS in In-Ga-Zn oxide, the second region has [Ga] higher than [Ga] in the composition of the CAC-OS film. Or, for example, [In] in the first region is higher than [In] in the second region, and [Ga] in the first region is lower than [Ga] in the second region. Also, the second region has [Ga] higher and [In] lower than the first region.

[0369] Specifically, the first region comprises indium oxide or indium zinc oxide, etc. as a main component. The second region comprises gallium oxide or gallium zinc oxide, etc. as a main component. That is, the first region can be described as a region comprising In as a main component. The second region can be described as a region comprising Ga as a main component.

[0370] In addition, there are cases where a clear boundary cannot be observed between the first region and the second region.

[0371] In the material composition of CAC-OS in In-Ga-Zn oxides containing In, Ga, Zn, and O, regions containing Ga as the main component are observed in parts of the CAC-OS, and regions containing In as the main component are observed in parts of the CAC-OS. These regions are randomly dispersed to form a mosaic pattern. Therefore, it is suggested that CAC-OS has a structure in which metal elements are unevenly distributed.

[0372] CAC-OS can be formed, for example, by a sputtering method under conditions where the substrate is not heated. When forming CAC-OS by a sputtering method, it is preferable to use one or more selected from an inert gas (typically argon), oxygen gas, and nitrogen gas as the deposition gas. The ratio of the oxygen gas flow rate to the total flow rate of the deposition gas during film formation is preferably as low as possible; for example, the oxygen gas flow rate ratio is preferably 0% or more and less than 30%, and more preferably 0% or more and less than 10%.

[0373] For example, energy dispersive X-ray spectroscopy (EDX) is used to obtain an EDX mapping, and according to the EDX mapping, the CAC-OS in In-Ga-Zn oxide has a composition in which regions containing In as the main component (first region) and regions containing Ga as the main component (second region) are unevenly distributed and mixed.

[0374] Here, the first region has higher conductivity than the second region. In other words, the conductivity of the metal oxide is manifested by carrier flow in the first region. Therefore, if the first region is distributed in a cloud-like manner in the metal oxide, high field-effect mobility (μ) can be realized.

[0375] The second region has higher insulation than the first region. In other words, if the second region is distributed in the metal oxide, leakage current can be suppressed.

[0376] Therefore, when CAC-OS is used in a transistor, the conductive function attributed to the first region and the insulating function attributed to the second region act complementarily, allowing the CAC-OS to possess a switching function (On / Off function). In other words, CAC-OS has a conductive function in part of the material and an insulating function in another part, and as a whole, CAC-OS functions as a semiconductor. By separating the conductive and insulating functions, each function can be maximized. Therefore, by using CAC-OS in a transistor, a high on-state current ( I on It is possible to realize high electric field effect mobility (μ) and good switching operation.

[0377] Transistors containing CAC-OS have high reliability. Therefore, CAC-OS is suitable for use in various semiconductor devices, such as display devices.

[0378] Oxide semiconductors may have any of several structures exhibiting various and different characteristics. An oxide semiconductor of one embodiment of the present invention may include two or more of amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0379] This embodiment can be appropriately combined with any of the other embodiments.

[0380] (Embodiment 4)

[0381] In this embodiment, a display device of one form of the present invention will be described with reference to FIG. 15.

[0382] The display device of this embodiment m line n heat( m and n It includes a plurality of pixels arranged in a matrix of integers greater than or equal to 1. FIG. 15 shows pixels (PIX( i , j ))( i is 1 or more m Integers less than or equal to, j is 1 or more n An example of a circuit diagram of the following integers is shown.

[0383] The pixel (PIX) of Fig. 15 i , j A pixel (PIX) includes a light-emitting device (110) (also called a light-emitting element), a switch (SW21), a transistor (M), and a capacitance element (C1). i , j )) may further include a switch (SW22). Here, for example, a light-emitting diode is used as the light-emitting device (110). In particular, it is preferable to use a micro light-emitting diode as the light-emitting device (110).

[0384] In this embodiment, a transistor is used as the switch (SW21). The gate of the switch (SW21) is a scan line (GL1( iIt is electrically connected to )). One of the source and drain of the switch (SW21) is the signal line (SL( j It is electrically connected to the source and drain, and the other side is electrically connected to the gate of the transistor (M).

[0385] In this embodiment, a transistor is used as the switch (SW22). The gate of the switch (SW22) is a scan line (GL2( i It is electrically connected to the source and drain of the switch (SW22). One of the source and drain is electrically connected to the wiring (COM), and the other of the source and drain is electrically connected to the gate of the transistor (M).

[0386] The gate of the transistor (M) is electrically connected to one electrode of the capacitance element (C1), the other side of the source and drain of the switch (SW21), and the other side of the source and drain of the switch (SW22). One side of the source and drain of the transistor (M) is electrically connected to the wiring (CATHODE), and the other side of the source and drain is electrically connected to the cathode of the light-emitting device (110).

[0387] The other electrode of the capacitive element (C1) is electrically connected to the wiring (CATHODE).

[0388] The anode of the light-emitting device (110) is electrically connected to the wiring (ANODE).

[0389] Scan line (GL1( i )) has the function of supplying a selection signal. Scan line (GL2( i )) has the function of supplying control signals. Signal line (SL( j )) has the function of supplying an image signal. A constant potential is supplied to each of the wiring (COM), wiring (CATHODE), and wiring (ANODE). In the light-emitting device (110), the anode side can be set to a high potential, and the cathode side can be set to a lower potential than the anode side.

[0390] The switch (SW21) is controlled by a selection signal, and the pixel (PIX) i , j It functions as a select transistor to control the selection state of )).

[0391] The transistor (M) functions as a driving transistor that controls the current flowing through the light-emitting device (110) according to the potential supplied to the gate. When the switch (SW21) is on, the signal line (SL( j An image signal supplied to )) is supplied to the gate of the transistor (M), and the brightness of the light-emitting device (110) can be controlled according to the potential of the image signal.

[0392] The switch (SW22) has the function of controlling the gate potential of the transistor (M) based on a control signal. Specifically, the switch (SW22) can supply a potential to the gate of the transistor (M) to turn off the transistor (M).

[0393] The switch (SW22) can be used, for example, to control the pulse width. It can supply current from the transistor (M) to the light-emitting device (110) for a period based on the control signal. The light-emitting device (110) can express a grayscale based on the image signal and the control signal.

[0394] Here, pixel(PIX( i , j For each of the transistors included in )), it is preferable to use a transistor containing a metal oxide (oxide semiconductor) in the semiconductor layer where the channel is formed.

[0395] Transistors containing metal oxides, which have a wider band gap and lower carrier density than silicon, have a very low off-state current. Therefore, because the off-state current is low, the charge accumulated in the capacitance element connected in series with the transistor can be maintained for a long period. Therefore, it is particularly desirable to use a transistor containing an oxide semiconductor as each of the switches (SW21 and SW22) connected in series with the capacitance element (C1). If the other transistors also each contain an oxide semiconductor, the manufacturing cost can be reduced.

[0396] or pixel (PIX) i , j As a transistor included in )), a transistor including silicon can be used as the semiconductor in which the channel is formed. In particular, using silicon with high crystallinity, such as single-crystal silicon or polycrystalline silicon, is desirable because it can realize high field-effect mobility and perform operation at a higher speed.

[0397] or pixel (PIX) i , j It is also acceptable to adopt a structure in which one or more of the transistors included in )) use a transistor containing an oxide semiconductor, and another transistor containing silicon is used.

[0398] Also, in Fig. 15, the transistor is an n-channel transistor, but a p-channel transistor can also be used.

[0399] This embodiment can be appropriately combined with any of the other embodiments.

[0400] (Embodiment 5)

[0401] In this embodiment, an electronic device of one form of the present invention will be described with reference to FIGS. 16 (A) and (B), FIGS. 17 (A) and (B), FIGS. 18 (A) and (B), FIGS. 19 (A) and (B), FIGS. 20 (A), (B), (C), and (D), and FIGS. 21 (A), (B), (C), (D), (E), and (F).

[0402] Each electronic device of the present embodiment is provided with a display device of one form of the present invention in its display section. The display device of one form of the present invention has high display quality and low power consumption. In addition, the display device of one form of the present invention can easily increase resolution and precision. Therefore, the display device of one form of the present invention can be used in the display section of various electronic devices.

[0403] Examples of electronic devices include, in addition to electronic devices having a relatively large screen such as television devices, desktop or laptop personal computers, monitors for computers, digital signage, and large game machines such as pachinko machines, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, and sound playback devices.

[0404] In particular, since one form of the present invention can increase the resolution, it can be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type or bracelet-type information terminals (wearable devices), and wearable devices mounted on the head such as VR devices such as head-mounted displays, glasses-type AR devices, and MR devices.

[0405] In one embodiment of the present invention, the resolution of the display device is preferably high, such as HD (pixels: 1280 x 720), FHD (pixels: 1920 x 1080), WQHD (pixels: 2560 x 1440), WQXGA (pixels: 2560 x 1600), 4K (pixels: 3840 x 2160), or 8K (pixels: 7680 x 4320). In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (resolution) of the display device in 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 3000 ppi or higher, more preferably 5000 ppi or higher, and further more preferably 7000 ppi or higher. By using a display device with such high resolution and precision, the realism and depth of electronic devices can be further enhanced for personal use, such as portable and home use.

[0406] The electronic device of the present embodiment may include a sensor (a sensor having the function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, inclination, vibration, odor, or infrared radiation).

[0407] The electronic device of the present embodiment may have various functions. For example, an electronic device of one form of the present invention may have a function of displaying various data (still images, video, and text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, and time, etc., a function of executing various software (programs), a wireless communication function, and a function of reading programs or data stored on a recording medium.

[0408] FIG. 16 (A) is a perspective view of an eyeglass-type electronic device (700). The electronic device (700) includes a pair of display panels (701), a pair of housings (702), a pair of optical members (703), a pair of temples (704), a frame (707), and nose pads (708), etc.

[0409] The electronic device (700) can project an image displayed on a display panel (701) onto a display area (706) of an optical member (703). Since the optical member (703) has light transmittance, the user can see the image displayed on the display area (706) superimposed on the transmitted image visible through the optical member (703). Thus, the electronic device (700) is an electronic device capable of AR display.

[0410] One or each of the housings (702) may be provided with a camera capable of capturing what is in front of them. The housing (702) may have a wireless communication device and may supply video signals, etc. to the housing (702) via this wireless communication device. In addition, a connector may be provided to which a cable supplying video signals or power potential can be connected, for example, instead of or in addition to the wireless communication device. In addition, if an accelerometer sensor, such as a gyroscope sensor, is provided in the housing (702), the direction of the user's head can be detected and an image corresponding to that direction can be displayed in the display area (706).

[0411] A processor may be provided in one or each of the housings (702). The processor has the function of controlling components of the electronic device (700), such as a camera, a wireless communication device, and a pair of display panels (701), and the function of generating images. The processor may have the function of generating composite images for AR display.

[0412] Data communication with an external device can be performed via a wireless communication device. For example, data transmitted from the outside can be output to a processor, and the processor can generate image data for AR display based on this data. Examples of data transmitted from the outside include image data and data containing biometric information transmitted from a biosensor device, etc.

[0413] A method for projecting an image onto a display area (706) of an electronic device (700) is described with reference to (B) of FIG. 16. A display panel (701) is provided inside a housing (702). A reflector (712) is provided on an optical member (703), and a reflective surface (713) that functions as a half mirror is provided on a portion of the optical member (703) corresponding to the display area (706).

[0414] Light (715) emitted from the display panel (701) is reflected toward the optical member (703) by the reflector (712). At the optical member (703), the light (715) undergoes repeated total internal reflection by the end surface of the optical member (703) and reaches the reflective surface (713), thereby projecting an image onto the reflective surface (713). Accordingly, the user can see both the light (715) reflected by the reflective surface (713) and the transmitted light (716) that has passed through the optical member (703) (including the reflective surface (713)).

[0415] Figures 16 (A) and (B) illustrate examples in which the reflector (712) and the reflective surface (713) each have a curved surface. By using this structure, the degree of freedom in optical design is increased compared to the case where the reflector (712) and the reflective surface (713) are flat, and the thickness of the optical member (703) can be reduced. Additionally, the reflector (712) and the reflective surface (713) may be flat.

[0416] The reflector (712) can be a part having a mirror surface, and it is preferable that it has a high reflectivity. As for the reflective surface (713), a half mirror utilizing the reflection of a metal film may be used, but if a total reflection prism is used, the transmittance of the transmitted light (716) can be increased.

[0417] Here, the housing (702) may include a lens between the display panel (701) and the reflector (712). Here, it is preferable that the housing (702) include a mechanism for adjusting the distance and angle between the lens and the display panel (701), in which case the focus can be adjusted and the image can be enlarged and reduced. For example, it is preferable that at least one of the lens and the display panel (701) be configured to move in the direction of the optical axis.

[0418] It is preferable that the housing (702) includes a mechanism capable of adjusting the angle of the reflector (712). By changing the angle of the reflector (712), the position of the display area (706) where the image is displayed can be changed. Accordingly, the display area (706) can be positioned at an optimal location according to the position of the user's eyes.

[0419] It is preferable that the housing (702) be provided with a battery (717) and a wireless power supply module (718). By having the battery (717), the electronic device (700) can be used without connecting another battery, thus increasing convenience. Additionally, by having the wireless power supply module (718), wireless charging is possible, thereby increasing convenience and design. Furthermore, compared to charging via a wired connection using a connector, the risk of failure such as poor contact can be reduced, thus increasing the reliability of the electronic device (700). The battery may also be provided in the temple (704).

[0420] A touch sensor module (719) is provided in the housing (702). The touch sensor module (719) has the function of detecting whether the outer surface of the housing (702) is touched. In (B) of FIG. 16, the surface of the housing (702) is touched by a finger (720). By detecting the user's tap operation or slide operation, etc., through the touch sensor module (719), various processing can be performed. For example, processing such as pausing or resuming a video can be performed by tap operation, and processing such as fast-forwarding or rewinding can be performed by slide operation. By providing a touch sensor module (719) to each of the two housings (702), the range of operations can be expanded.

[0421] Various touch sensors may be applied to the touch sensor module (719). Any of the various types of touch sensors, such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, and optical types, may be adopted. In particular, it is preferable to use a capacitive sensor or an optical sensor in the touch sensor module (719).

[0422] When using an optical touch sensor, a photoelectric conversion device (also called a photoelectric conversion element) may be used as a light receiving device (also called a light receiving element). Examples of photoelectric conversion devices include photoelectric conversion devices using an inorganic semiconductor or an organic semiconductor in the active layer.

[0423] A display device of one form of the present invention may be used in the display panel (701). Thus, an electronic device (700) capable of displaying very high resolution can be provided.

[0424] Figure 17 (A) is a perspective view of an eyeglass-type electronic device (900). The electronic device (900) includes a pair of display panels (901), a pair of housings (902), a pair of optical members (903), and a pair of eyeglass temples (904), etc.

[0425] The electronic device (900) can project an image displayed on a display panel (901) onto a display area (906) of an optical member (903). Since the optical member (903) has light transmittance, the user can see the image displayed on the display area (906) superimposed on the transmitted image visible through the optical member (903). Thus, the electronic device (900) is an electronic device capable of AR display.

[0426] It is preferable that the display panel (901) included in the electronic device (900) has a function of capturing an image in addition to a function of displaying an image. In this case, the electronic device (900) can receive light incident on the display panel (901) through an optical member (903), convert this light into an electrical signal, and output this electrical signal. By doing so, an image of the user's eye, or the user's eye and its surroundings, can be captured, and this image can be output as image information to an external or a processing unit included in the electronic device (900).

[0427] Each housing (902) includes a camera (905) capable of capturing what is in front of it. Although not shown in the drawing, a connector capable of connecting a wireless receiver or a cable to one side of the housing (902) can be provided to supply video signals, etc. to the housing (902). Additionally, by providing an accelerometer sensor, such as a gyroscope sensor, to the housing (902), the direction of the user's head can be detected, and an image corresponding to that direction can be displayed in the display area (906). Furthermore, it is preferable that the housing (902) be provided with a battery that can be charged wirelessly or via a wire.

[0428] Next, a method for projecting an image onto a display area (906) of an electronic device (900) is described with reference to (B) of FIG. 17. A housing (902) is provided with a display panel (901), a lens (911), and a reflector (912). As a portion corresponding to the display area (906) of the optical member (903), a reflective surface (913) that functions as a half mirror is provided.

[0429] Light (915) emitted from the display panel (901) passes through the lens (911) and is reflected toward the optical member (903) by the reflector (912). At the optical member (903), the light (915) undergoes repeated total internal reflection by the end surface of the optical member (903) and reaches the reflective surface (913), thereby projecting an image onto the reflective surface (913). Accordingly, the user can see both the light (915) reflected by the reflective surface (913) and the transmitted light (916) that has passed through the optical member (903) (including the reflective surface (913)).

[0430] Figures 17 (A) and (B) illustrate examples in which the reflector (912) and the reflective surface (913) each have a curved surface. By using this structure, the degree of freedom in optical design is increased compared to the case where the reflector (912) and the reflective surface (913) are flat, and the thickness of the optical member (903) can be reduced. Additionally, the reflector (912) and the reflective surface (913) may be flat.

[0431] The reflector (912) can be a part having a mirror surface, and it is preferable that it has a high reflectivity. As for the reflective surface (913), a half mirror utilizing the reflection of a metal film may be used, but if a total reflection prism is used, the transmittance of the transmitted light (916) can be increased.

[0432] Here, the electronic device (900) preferably includes a mechanism for adjusting the distance and / or angle between the lens (911) and the display panel (901), in which case, for example, the focus can be adjusted and the image can be enlarged and reduced. For example, it is preferable that at least one of the lens (911) and the display panel (901) be configured to move in the direction of the optical axis.

[0433] It is preferable that the electronic device (900) includes a mechanism capable of adjusting the angle of the reflector (912). By changing the angle of the reflector (912), the position of the display area (906) where the image is displayed can be changed. Accordingly, the display area (906) can be positioned at an optimal location according to the position of the user's eyes.

[0434] A display device of one form of the present invention may be used in the display panel (901). Thus, an electronic device (900) capable of displaying very high resolution can be provided.

[0435] Figures 18 (A) and (B) are perspective views of a goggle-type electronic device (950). Figure 18 (A) is a perspective view showing the front, top, and left side of the electronic device (950), and Figure 18 (B) is a perspective view showing the back, bottom, and right side of the electronic device (950).

[0436] The electronic device (950) includes a pair of display panels (951), a housing (952), a pair of eyeglass temples (954), a cushioning member (955), and a pair of lenses (956), etc. The pair of display panels (951) are positioned so as to be visible through the lenses (956) inside the housing (952).

[0437] The electronic device (950) is a VR electronic device. A user wearing the electronic device (950) can see an image displayed on a display panel (951) through a lens (956). Additionally, by displaying different images on a pair of display panels (951), a three-dimensional display using parallax can be performed.

[0438] An input terminal (957) and an output terminal (958) are provided at the rear of the housing (952). A cable supplying a video signal from a video output device, etc., or power for charging a battery provided in the housing (952), etc., can be connected to the input terminal (957). The output terminal (958) can function, for example, as a voice output terminal and can connect earphones or headphones, etc. Additionally, if voice data can be output via wireless communication or if voice is output from an external video output device, the voice output terminal does not need to be provided.

[0439] It is preferable that the electronic device (950) includes a mechanism capable of adjusting the left and right positions of the lens (956) and the display panel (951) to an optimal position according to the position of the user's eyes. Additionally, it is preferable that the electronic device (950) includes a mechanism for adjusting the focus by changing the distance between the lens (956) and the display panel (951).

[0440] A display device of one form of the present invention may be used in the display panel (951). Thus, an electronic device (950) capable of displaying very high resolution can be provided. As a result, the user can obtain a high sense of immersion.

[0441] The cushioning member (955) comes into contact with the user's face (forehead or cheek, etc.). Since light leakage can be prevented when the cushioning member (955) is in close contact with the user's face, the sense of immersion can be enhanced. It is preferable to use a soft material for the cushioning member (955) so that the cushioning member (955) comes into close contact with the user's face, which is equipped with the electronic device (950). For example, materials such as silicone rubber, urethane, or sponge can be used. Additionally, if a sponge or similar material with a surface covered with a chuck or leather (natural leather or synthetic leather) is used as the cushioning member (955), it is difficult for a gap to form between the user's face and the cushioning member (955), thus effectively preventing light leakage. It is preferable that the cushioning member (955) or the temple (954), which come into contact with the user's skin, be detachable so that cleaning or replacement can be easily performed.

[0442] The electronic device (6500) shown in (A) of Fig. 19 is a portable information terminal that can be used as a smartphone.

[0443] The electronic device (6500) includes a housing (6501), a display unit (6502), a power button (6503), a button (6504), a speaker (6505), a microphone (6506), a camera (6507), and a light source (6508), etc. The display unit (6502) has a touch panel function.

[0444] A display device of one form of the present invention may be used in the display unit (6502).

[0445] (B) of FIG. 19 is a schematic cross-sectional view including the end of the housing (6501) on the side of the microphone (6506).

[0446] A protective member (6510) having light transmittance is provided on the display side of the housing (6501), and a display panel (6511), an optical member (6512), a touch sensor panel (6513), a printed circuit board (6517), and a battery (6518) are provided within the space enclosed by the housing (6501) and the protective member (6510).

[0447] In the protective member (6510), a display panel (6511), an optical member (6512), and a touch sensor panel (6513) are fixed by an adhesive layer (not shown in the drawing).

[0448] A portion of the display panel (6511) is folded in an area outside the display section (6502), and an FPC (6515) is connected to this folded portion. An IC (6516) is mounted on the FPC (6515). The FPC (6515) is connected to a terminal provided on a printed circuit board (6517).

[0449] As the display panel (6511), a flexible display of one form of the present invention can be used. Therefore, a very lightweight electronic device can be provided. Since the display panel (6511) is very thin, a large capacity battery (6518) can be installed while controlling the thickness of the electronic device. By folding a part of the display panel (6511) and placing a part connected to the FPC (6515) behind the pixel part, an electronic device with a narrow frame can be obtained.

[0450] An example of a television device is shown in (A) of FIG. 20. In the television device (7100), a display unit (7000) is included in the housing (7101). Here, a structure is shown in which the housing (7101) is supported by a stand (7103).

[0451] A display device of one form of the present invention may be used in the display unit (7000).

[0452] The operation of the television device (7100) shown in (A) of FIG. 20 can be performed by an operation switch provided in the housing (7101) or by a separate remote controller (7111). Alternatively, the display unit (7000) may include a touch sensor, and the television device (7100) may be operated by touching the display unit (7000) with a finger or the like. The remote controller (7111) may be provided with a display unit that displays data output from the remote controller (7111). By means of an operation key or touch panel provided in the remote controller (7111), the channel and volume can be operated, and the image displayed on the display unit (7000) can be operated.

[0453] Additionally, the television device (7100) has a structure provided with a receiver and a modem, etc. It can receive general television broadcasts through the receiver. By connecting the television device to a communication network via a wired or wireless connection through the modem, it can perform unidirectional (from sender to receiver) or bidirectional (e.g., between sender and receiver or between receivers) data communication.

[0454] Figure 20 (B) shows an example of a notebook-type personal computer. The notebook-type personal computer (7200) includes a housing (7211), a keyboard (7212), a pointing device (7213), and an external connection port (7214), etc. The housing (7211) includes a display unit (7000).

[0455] A display device of one form of the present invention may be used in the display unit (7000).

[0456] Examples of digital signage are shown in (C) and (D) of Fig. 20.

[0457] The digital signage (7300) shown in (C) of FIG. 20 includes a housing (7301), a display unit (7000), and a speaker (7303), etc. Additionally, the digital signage may include an LED lamp, an operation key (including a power switch or an operation switch), a connection terminal, various sensors, and a microphone, etc.

[0458] (D) of FIG. 20 is a digital signage (7400) mounted on a cylindrical column (7401). The digital signage (7400) includes a display (7000) provided along the curved surface of the column (7401).

[0459] In the display portion (7000) shown in each of (C) and (D) of FIG. 20, a display device of one form of the present invention may be used.

[0460] The larger the area of ​​the display section (7000), the more data can be provided at once. Since the larger the display section (7000), the more noticeable it is, for example, the effect of the advertisement can be increased.

[0461] It is desirable to use a touch panel on the display unit (7000) so that, in addition to displaying still images or videos on the display unit (7000), intuitive operation by the user is also possible. Furthermore, in the case of providing information such as route information or traffic information, usability can be enhanced through intuitive operation.

[0462] As shown in (C) and (D) of FIG. 20, it is preferable that the digital signage (7300) or digital signage (7400) be connected via wireless communication with an information terminal (7311) or information terminal (7411), such as a smartphone owned by the user. For example, information about an advertisement displayed on the display unit (7000) can be displayed on the screen of the information terminal (7311) or information terminal (7411). By operating the information terminal (7311) or information terminal (7411), the display of the display unit (7000) can be switched.

[0463] A game can be executed on digital signage (7300) or digital signage (7400) using the screen of an information terminal (7311) or an information terminal (7411) as a means of operation (controller). By doing so, an unspecified number of users can simultaneously participate in and enjoy the game.

[0464] The electronic device shown in (A) to (F) of FIG. 21 includes a housing (9000), a display unit (9001), a speaker (9003), an operation key (9005) (including a power switch or an operation switch), a connection terminal (9006), a sensor (9007) (a sensor having the function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, longitude, electric field, current, voltage, power, radiation, flow rate, humidity, inclination, vibration, smell, or infrared), and a microphone (9008), etc.

[0465] The electronic device shown in (A) to (F) of FIG. 21 has various functions. For example, the electronic device may have a function of displaying various data (still images, video, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, time, etc., a function of controlling processing using various software (programs), a wireless communication function, and a function of reading and processing programs or data stored on a recording medium. Furthermore, the functions of the electronic device are not limited to these, and the electronic device may have various functions. The electronic device may include a plurality of display units. Each electronic device may include a camera, etc., and may have a function of capturing a still image or video, saving the captured image to a recording medium (an external recording medium or a recording medium included in the camera), or a function of displaying the captured image on a display unit.

[0466] Detailed information regarding the electronic devices shown in (A) to (F) of FIG. 21 will be explained below.

[0467] FIG. 21 (A) is a perspective view showing a portable information terminal (9101). The portable information terminal (9101) can be used, for example, as a smartphone. Additionally, the portable information terminal (9101) may be provided with a speaker (9003), a connection terminal (9006), or a sensor (9007), etc. The portable information terminal (9101) may display text and image information on its multiple surfaces. FIG. 21 (A) shows an example in which three icons (9050) are displayed. Information (9051) represented by a dashed rectangle may be displayed on another surface of the display unit (9001). Examples of information (9051) include the reception of an email, the reception of an SNS message, or a notification of an incoming phone call, the subject and sender name of the email or SNS message, etc., date and time, time, remaining battery level, and signal strength. Alternatively, an icon (9050), etc., may be displayed at the location where the information (9051) is displayed.

[0468] FIG. 21 (B) is a perspective view showing a portable information terminal (9102). The portable information terminal (9102) has the 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 the information (9053) displayed at a position that can be observed from the top of the portable information terminal (9102) while the portable information terminal (9102) is placed in the chest pocket of clothing. The user can see the display without taking the portable information terminal (9102) out of the pocket and, for example, decide whether to answer a phone call.

[0469] FIG. 21 (C) is a perspective view showing a wristwatch-type portable information terminal (9200). The portable information terminal (9200) can be used, for example, as a smartwatch. The display surface of the display unit (9001) is provided in a curved shape, and display can be performed along the curved display surface. For example, hands-free calling can be made by the portable information terminal (9200) communicating with a headset capable of wireless communication. The portable information terminal (9200) can perform mutual data transmission and charging with other information terminals via a connection terminal (9006). Additionally, the charging operation may be performed by wireless power supply.

[0470] Figures 21 (D) to (F) are perspective views showing a foldable portable information terminal (9201). Figure 21 (D) is a perspective view of the portable information terminal (9201) in an unfolded state, Figure 21 (F) is a perspective view of the portable information terminal (9201) in a folded state, and Figure 21 (E) is a perspective view of the state in progress of changing from one side of Figures 21 (D) and (F) to the other. The portable information terminal (9201) has high portability when folded and high visibility when unfolded because it has a large, seamless display area. The display unit (9001) of the portable information terminal (9201) is supported by three housings (9000) connected by a hinge (9055). For example, the display part (9001) can be folded with a radius of curvature of 0.1 mm or more and 150 mm or less.

[0471] This embodiment can be appropriately combined with other embodiments. Explanation of the symbols

[0472] ANODE: Wiring, CCMG: Color conversion layer, CCMR: Color conversion layer, CFB: Coloring layer, CFG: Coloring layer, CFR: Coloring layer, COM: Wiring, PIX: Pixel, SL: Signal line, SW21: Switch, SW22: Switch, 100A: Display device, 100B: Display device, 100C: Display device, 100D: Display device, 100E: Display device, 100F: Display device, 100G: Display device, 100H: Display device, 101: Substrate, 102: Insulating layer, 103: Insulating layer, 104: Insulating layer, 105: Light-shielding layer, 106: Light-shielding layer, 109: Underlayer, 110a: Light-emitting diode, 110b: Light-emitting diode, 110c: Light-emitting diode, 110: Light-emitting device, 113a: Semiconductor layer, 113b: Semiconductor layer, 113: Semiconductor layer, 114a: Emitting layer, 114b: Emitting layer, 114: Emitting layer, 115a: Semiconductor layer, 115b: Semiconductor layer, 115: Semiconductor layer, 116a: Conductive layer, 116b: Conductive layer, 116c: Conductive layer, 116d: Conductive layer, 116e: Conductive layer, 116f: Conductive layer, 117a: Electrode, 117b: Electrode, 117c: Electrode, 117d: Electrode, 117e: Electrode, 117f: Electrode, 117: Electrode, 120a: Transistor, 120b: Transistor, 120c: Transistor, 130a: Transistor, 130b: Transistor, 130c: Transistor, 131: Substrate, 132: Device isolation layer, 133: Low resistance region, 134: Insulating layer, 135: Conductive layer, 136: Insulating layer, 137: Conductive layer, 138: Conductive layer, 139: Insulating layer, 141: Insulating layer, 142: Conductive layer, 143: Insulating layer, 150A: LED substrate, 150B: Circuit board, 150C: LED substrate, 150D: Circuit board, 151: Substrate, 152: Insulating layer, 161: Conductive layer, 162: Insulating layer, 163: Insulating layer, 164: Insulating layer, 165: Metal oxide layer, 166: Conductive layer, 167: Insulating layer, 168: Conductive layer, 171: Substrate, 172: Wiring, 173: Insulating layer, 174: Electrode, 175: Conductive layer, 176: Connector,177: Electrode, 178: Electrode, 179: Adhesive layer, 181: Insulating layer, 182: Insulating layer, 183: Insulating layer, 184a: Conductive layer, 184b: Conductive layer, 185: Insulating layer, 186: Insulating layer, 187: Insulating layer, 188: Insulating layer, 189a: Conductive layer, 189b: Conductive layer, 189c: Conductive layer, 189d: Conductive layer, 190a: Conductive layer, 190b: Conductive layer, 190c: Conductive layer, 190d: Conductive layer, 190e: Conductive layer, 190f: Conductive layer, 190: Conductive layer, 191: Substrate, 192: Adhesive layer, 195: Conductor, 200: Transistor, 205a: Conductor, 205b: Conductor, 205c: Conductor, 205: Conductor, 212: Insulator, 214: Insulator, 216: Insulator, 222: Insulator, 224: Insulator, 230a: Oxide, 230b: Oxide, 230: Oxide, 240a: Conductor, 240b: Conductor, 240: Conductor, 241a: Insulator, 241b: Insulator, 241: Insulator, 242a: Conductor, 242b: Conductor, 242: Conductor, 243a: Oxide, 243b: Oxide, 243: Oxide, 246a: Conductor, 246b: Conductor, 246: Conductor, 250a: Insulator, 250b: Insulator, 250: Insulator, 260a: Conductor, 260b: Conductor, 260: Conductor, 271a: Insulator, 271b: Insulator, 271: Insulator, 275: Insulator, 280: Insulator, 282: Insulator, 283: Insulator, 285: Insulator, 700: Electronic device, 701: Display panel, 702: Housing, 703: Optical component, 704: Eyeglass temple, 706: Display area, 707: Frame, 708: Nose pad, 712: Reflector, 713: Reflective surface, 715: Light, 716: Transmitted light, 717: Battery, 718: Wireless power supply module, 719: Touch sensor module, 720: Finger, 900: Electronic device, 901: Display panel, 902: Housing, 903: Optical component, 904: Eyeglass temple, 905: Camera, 906: Display area, 911: Lens, 912: Reflector, 913: Reflective surface,915: Light, 916: Transmitted light, 950: Electronic device, 951: Display panel, 952: Housing, 954: Eyeglass temple, 955: Cushioning member, 956: Lens, 957: Input terminal, 958: Output terminal, 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 controller, 7200: Laptop-type personal computer, 7211: Housing, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Housing, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Housing, 9001: Display unit, 9003: Speaker, 9005: Operation key, 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., The present application is based on Japanese patent application No. 2019-205030 filed with the Japan Patent Office on November 12, 2019 and Japanese patent application No. 2019-220314 filed with the Japan Patent Office on December 5, 2019, the full text of which is incorporated by reference into this specification.

Claims

Claim 1 A display device comprising: a first transistor; a first conductive layer positioned above the first transistor and electrically connected to the first transistor; a first insulating layer positioned above the first transistor; a second conductive layer positioned above the first conductive layer; a second insulating layer positioned above the first insulating layer and electrically connected to the second conductive layer; a light-emitting diode positioned above the second insulating layer and electrically connected to the second conductive layer; and a third insulating layer between the first transistor and the first insulating layer. A display device comprising a fourth insulating layer between the light-emitting diode and the second insulating layer, wherein the upper surface of the first conductive layer has the same height as the upper surface of the first insulating layer, the lower surface of the second conductive layer has the same height as the lower surface of the second insulating layer, the first insulating layer and the second insulating layer are bonded to each other, the first conductive layer and the second conductive layer are bonded to each other, the first insulating layer and the second insulating layer each comprise silicon oxide, and the third insulating layer and the fourth insulating layer each comprise at least one of aluminum oxide, hafnium oxide, and silicon nitride. Claim 2 A display device comprising: a second transistor including a channel forming region on a semiconductor substrate; a first transistor above the second transistor; a first conductive layer above the first transistor and electrically connected to the first transistor; a first insulating layer above the first transistor; a second conductive layer above the first conductive layer; a second insulating layer above the first insulating layer; a light-emitting diode above the second insulating layer and electrically connected to the second conductive layer; and a third insulating layer between the first transistor and the first insulating layer. A display device comprising a fourth insulating layer between the light-emitting diode and the second insulating layer, wherein the upper surface of the first conductive layer has the same height as the upper surface of the first insulating layer, the lower surface of the second conductive layer has the same height as the lower surface of the second insulating layer, the first insulating layer and the second insulating layer are bonded to each other, the first conductive layer and the second conductive layer are bonded to each other, the first insulating layer and the second insulating layer each comprise silicon oxide, and the third insulating layer and the fourth insulating layer each comprise at least one of aluminum oxide, hafnium oxide, and silicon nitride. Claim 3 A display device according to claim 1 or 2, wherein the angle between the bottom surface of the first conductive layer and the side surface of the first conductive layer is greater than 0° and less than or equal to 90°, and the angle between the bottom surface of the second conductive layer and the side surface of the second conductive layer is 90° or more and less than 180°. Claim 4 A display device according to claim 1 or 2, further comprising a fifth insulating layer, wherein the upper surface of the gate electrode of the first transistor has the same height as the upper surface of the fifth insulating layer. Claim 5 A display device according to claim 1 or 2, further comprising a fifth insulating layer, wherein the first transistor comprises a metal oxide layer, a gate insulating layer, a gate electrode, a third conductive layer, and a fourth conductive layer, wherein the metal oxide layer comprises a first region overlapping with the third conductive layer, a second region overlapping with the fourth conductive layer, and a third region between the first region and the second region, wherein the third conductive layer and the fourth conductive layer are located on the metal oxide layer, wherein the fifth insulating layer is located on the third conductive layer and the fourth conductive layer, wherein the fifth insulating layer comprises an opening overlapping with the third region, wherein the gate insulating layer is located inside the opening and overlaps with the side surface of the fifth insulating layer and the upper surface of the third region, and the gate electrode is located inside the opening and overlaps with the side surface of the fifth insulating layer and the upper surface of the third region through the interposition of the gate insulating layer. Claim 6 A display device according to claim 1 or 2, wherein the first conductive layer and the second conductive layer each comprise gold. Claim 7 A display device according to claim 1 or 2, further comprising a functional layer above the light-emitting diode, wherein light emitted from the light-emitting diode is extracted to the outside of the display device through the functional layer, and the functional layer comprises one or both of a coloring layer and a color conversion layer. Claim 8 A display device according to claim 1 or 2, wherein the light-emitting diode is a micro light-emitting diode. Claim 9 A display device according to claim 1 or 2, wherein the light-emitting diode comprises a compound including a group 13 element and a group 15 element. Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete

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