Method of manufacturing a display device

Abstract

The present application relates to a manufacturing method of a display device. The display device performance is improved. The manufacturing method includes: (a) a step of preparing a first substrate in which a plurality of first inorganic light emitting elements are arranged in a row and column manner and an array substrate in which a plurality of first terminals are formed; (b) a step of measuring each of a thickness of the first substrate, a thickness of one or more first inorganic light emitting elements, and a thickness of the array substrate; (c) a step of pressing each of the plurality of first inorganic light emitting elements against the array substrate in a state that the first substrate held on a first worktable is opposed to the array substrate held on a second worktable, and electrically connecting the plurality of first terminals of the array substrate to the plurality of first inorganic light emitting elements; and (d) a step of peeling the first substrate from the plurality of first inorganic light emitting elements, and controlling a press-in amount of pressing each of the plurality of first inorganic light emitting elements against the array substrate based on a result of the measurement in the step (b) in the step (c).

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing technique of a display device. BACKGROUND

[0002] As a display device, there is an LED (Light Emitting Diode) display device in which inorganic light emitting diode elements as self-light emitting elements are arranged in a matrix on a substrate (for example, see Patent Literature 1 (Japanese Patent Application Publication No. 2020-67626)). In addition, as a higher-fineness display device, there is a micro LED display device that uses a minute inorganic light emitting diode element called a micro LED (for example, see Patent Literature 2 (Japanese Patent Application Publication No. 2019-36719)).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2020-67626

[0006] Patent Literature 2: Japanese Patent Application Publication No. 2019-36719 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] A manufacturing process of an LED display device and a manufacturing process of a micro LED display device include a process of mounting a plurality of LED elements (or micro LED elements) on a substrate. In the process of mounting a plurality of LED elements, the plurality of LED elements are pressed against the substrate. It is important to control the pressure (pressing force) with which the plurality of LED elements are pressed against the substrate at this time. For example, in the case where the pressing force is too large, the plurality of LED elements and the substrate can be damaged. In addition, in the case where the pressing force is too small, the reliability of electrical connection of a terminal formed on the substrate and the LED element can be reduced.

[0009] An object of the present application is to provide a technique for improving the performance of a display device that uses a plurality of inorganic light emitting diode elements.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] A manufacturing method of a display device of one embodiment of the present application includes the following steps. (a) A step of preparing a first substrate in which a plurality of first inorganic light emitting elements are arranged in a matrix and an array substrate in which a plurality of first terminals are formed. (b) A step of measuring each of the thickness of the first substrate, the thickness of one or more of the plurality of first inorganic light emitting elements, and the thickness of the array substrate. (c) A step of electrically connecting the plurality of first terminals of the array substrate and the plurality of first inorganic light emitting elements by pressing each of the plurality of first inorganic light emitting elements against the array substrate in a state where the first substrate held on a first stage opposes the array substrate held on a second stage. (d) A step of separating the first substrate and the plurality of first inorganic light emitting elements after the step (c). In the step (c), the strength with which each of the plurality of first inorganic light emitting elements is pressed against the array substrate is controlled on the basis of the results measured in the step (b). BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a top view illustrating a configuration example of a display device of one embodiment.

[0013] Figure 2 FIG. 2 is a circuit diagram illustrating a configuration example of a circuit around a pixel. Figure 1

[0014] Figure 3 FIG. 3 is an enlarged cross-sectional view illustrating an example of a peripheral structure of an LED element arranged around each of a plurality of pixels of a display device. Figure 1

[0015] Figure 4 FIG. 4 is an enlarged cross-sectional view illustrating a modification example of an LED element. Figure 3

[0016] Figure 5 FIG. 5 is an explanatory diagram illustrating a flow of a manufacturing process of a display device. Figure 1

[0017] Figure 6 FIG. 6 is a top view illustrating an outline of a substrate prepared in a step of preparing an LED holding substrate. Figure 5

[0018] Figure 7 FIG. 7 is a cross-sectional view illustrating an outline of an array substrate SUB1 prepared in a step of preparing an array substrate. Figure 5

[0019] Figure 8 FIG. 8 is a schematic view illustrating a manufacturing process of a display device. Figure 5 ​​​​​​A cross-sectional view of an example of a measurement site in the process of measuring thickness.

[0020] Figure 9 is a schematic view showing a state before the process of mounting the first LED element. Figure 5 is a schematic view showing an example of a method of measuring thickness in the process of measuring thickness.

[0021] Figure 10 is a schematic view showing a state before the process of mounting the second LED element. Figure 5 is a cross-sectional view of a state in which a substrate in which the first inorganic light emitting elements are arranged is pressed against the array substrate in the process of mounting the first LED element.

[0022] Figure 11 is a cross-sectional view of a state in which the holding substrate is peeled from the plurality of first inorganic light emitting elements in the process of peeling the first holding substrate. Figure 5

[0023] is a schematic view showing a state before the process of mounting the second LED element. Figure 12 Figure 5 is a cross-sectional view of a state in which a substrate in which the second inorganic light emitting elements are arranged is pressed against the array substrate in the process of mounting the second LED element.

[0024] Figure 13 Figure 5 is a cross-sectional view of a state in which the holding substrate is peeled from the plurality of second inorganic light emitting elements in the process of peeling the second holding substrate.

[0025] Figure 14 is a cross-sectional view of a state in which a substrate in which the third inorganic light emitting elements are arranged is pressed against the array substrate in the process of mounting the third LED element. Figure 5

[0026] is a cross-sectional view of a state in which the holding substrate is peeled from the plurality of third inorganic light emitting elements in the process of peeling the third holding substrate. Figure 15 Figure 5 is a schematic view showing a state before the process of mounting the third LED element.

[0027] Figure 16 is a modification of Figure 10 , and is a cross-sectional view schematically showing a state before the array substrate is mounted using the holding substrate in which a plurality of LED elements are simultaneously held.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] 5 control circuit

[0030] 6 drive circuit

[0031] 10, SS1, SS2, SS3, SS4 substrate

[0032] ​​​10b, 10f, 20b, 20f, 51b, 51t face

[0033] 11 inorganic insulating layer

[0034] 12 organic insulating layer

[0035] 13 organic insulating layer

[0036] 20, 20M1 LED element (inorganic light emitting element)

[0037] 20E electrode

[0038] 20EA anode

[0039] 20EK cathode

[0040] 21 first inorganic light emitting element

[0041] 22 second inorganic light emitting element

[0042] 23 third inorganic light emitting element

[0043] 30, 30H, 30L, 31, 32, 33 terminal

[0044] 40 electrically conductive bonding member

[0045] 50A, 50B sensor head

[0046] 51 workpiece

[0047] 52 laser light

[0048] 53A, 53B distance

[0049] 53C separation distance

[0050] 61, 62 worktable

[0051] 61h, 62h holding surface

[0052] BCT output switch

[0053] Cad auxiliary capacitor

[0054] Cs holding capacitor

[0055] DA display region

[0056] DRT drive transistor

[0057] DSP1 display device

[0058] EK cathode

[0059] GL, GLA, GLB scan signal line

[0060] GLR reset wiring

[0061] Gsb, Gsr, Gss control signals

[0062] IC driver

[0063] LED micro

[0064] PFA peripheral region

[0065] PIX pixel

[0066] PVD, PVS potential

[0067] RST reset wiring switch

[0068] SS1b, SS2b, SS3b, SS4b lower surface

[0069] SS1t, SS2t, SS3t, SS4t upper surface

[0070] SST pixel switch

[0071] SUB1 array substrate

[0072] SUBb face (second face)

[0073] SUBt face (first face)

[0074] VL image signal line

[0075] Vsg image signal DETAILED DESCRIPTION

[0076] Hereinafter, each embodiment of the present application will be described with reference to the drawings. Note that this disclosure is only one example, and appropriate modifications of the present application that a person skilled in the art can easily think of with the gist of the present application are of course included in the scope of the present application. In addition, the drawings are for the purpose of making the description clearer, and there are cases where the width, thickness, shape, etc. of each part are schematically represented compared to the actual form, but the drawings are only one example and are not intended to limit the explanation of the present application. In addition, in the present specification and each drawing, there are cases where the same or related reference numerals are appropriately omitted from detailed description for elements that are the same as those already explained with respect to the previous drawings.

[0077] In the following embodiment, as an example of a display device using a plurality of inorganic light emitting elements, a micro LED display device provided with a plurality of micro LED elements will be described. The micro LED element has an advantage of being able to display a high-resolution image because the size (outer diameter size) of the element is small compared to a general LED element. However, since the size of the micro LED element is small, the margin of the pressing force to be controlled is small in the light emitting diode element mounting process described later.

[0078] Note that a light-emitting diode element as a self-light-emitting element is an organic light-emitting diode element (OLED: Organic Light-Emitting Diode). The inorganic light-emitting diode element (micro LED element) described in the following embodiment is different from the organic light-emitting diode element.

[0079] <Display device>

[0080] First, a configuration example of a micro LED display device as a display device of the present embodiment will be described. Figure 1 is a top view illustrating a configuration example of a display device as one embodiment. In Figure 1 , the boundary between the display region DA and the peripheral region PFA, the control circuit 5, the driver circuit 6, and the plurality of pixels PIX are each indicated by a double-dotted line. Figure 2 is a circuit diagram illustrating a configuration example of a circuit around the pixel shown in Figure 1 .

[0081] As shown in Figure 1 , the display device DSP1 of the present embodiment has a display region DA, a peripheral region PFA positioned around the display region DA, and a plurality of pixels PIX arranged in a matrix within the display region DA. In addition, the display device DSP1 has a substrate 10, a control circuit 5 formed on the substrate 10, and a driver circuit 6 formed on the substrate 10.

[0082] The control circuit 5 is a control circuit that controls the driving of the display function of the display device DSP1. For example, the control circuit 5 is a driver IC (Integrated Circuit) mounted on the substrate 10. In the example shown in Figure 1 , the control circuit 5 is arranged along one of the short sides of the four sides of the substrate 10. In addition, in the example of the present embodiment, the control circuit 5 includes a signal line driver circuit that drives an image signal line VL (see Figure 2 ) connected to the plurality of pixels PIX. However, the position and the configuration example of the control circuit 5 are not limited to the example shown in Figure 1 . There are various modification examples. For example, in Figure 1 , there is a case where a flexible substrate or the like circuit substrate is connected at the position shown as the control circuit 5, and the above-described driver IC is mounted on the circuit substrate. In addition, for example, there is a case where the signal line driver circuit that drives the image signal line VL is formed independently of the control circuit 5.

[0083] The driver circuit 6 is a circuit that drives a scan signal line GL in the plurality of pixels PIX. The driver circuit 6 drives a plurality of scan signal lines GL based on a control signal from the control circuit 5. In Figure 1In the example shown, the drive circuits 6 are arranged along two of the long sides of the four sides of the substrate 10. However, the position and configuration of the drive circuits 6 are not limited to this example. Figure 1 The example shown has several variations. For example, in Figure 1 In some cases, a flexible substrate or other circuit board is connected to the position shown as the control circuit 5, and the aforementioned drive circuit 6 is mounted on the circuit board.

[0084] Next, use Figure 2 This section illustrates an example of the circuit configuration for a pixel (PIX). It should be noted that... Figure 2 In the image, a representative pixel (PIX) is shown. Figure 1 The multiple pixel PIX shown each has the same characteristics as... Figure 2 The circuit shown is the same as that of the pixel PIX. Hereinafter, the circuit including switches, capacitors, and LED elements 20 of the pixel PIX will be referred to as the pixel circuit. The pixel circuit is based on the control circuit 5 (see reference 5). Figure 1 The circuit uses a voltage signal to control the light-emitting state of the LED element 20 by supplying the image signal Vsg.

[0085] like Figure 2 As shown, the pixel PIX includes an LED element 20. The LED element 20 is the aforementioned micro-light-emitting diode. The LED element 20 has an anode 20EA (see below). Figure 3 ) and cathode EK (see below) Figure 3 The anode 20EA and cathode 20EK of LED element 20 are electrically connected to the terminals 30 of pixel PIX. Figure 2 In the example shown, the cathode 20EK of LED element 20 is connected to terminal 30L, and the anode 20EA of LED element 20 is connected to terminal 30H. Terminal 30L is supplied with a relatively low fixed potential (low potential) PVS, and terminal 30H is supplied with a higher fixed potential (high potential) PVD than the potential supplied to terminal 30L.

[0086] The pixel PIX has an output switch BCT, a drive transistor DRT, and a pixel switch SST. The output switch BCT is a transistor that controls the light emission time of the LED element 20 in response to a control signal Gsb supplied from the drive circuit 6. The drive transistor DRT is a transistor that controls the amount of current of the drive current supplied to the anode of the LED element 20 in accordance with the image signal Vsg. The pixel switch SST is a transistor that controls the connection state (on-off state) of the pixel circuit to the image signal line VL in response to a control signal Gss. In addition, the drive circuit 6 has a reset line switch RST that controls the input of the reset line potential. The output switch BCT, the drive transistor DRT, the pixel switch SST, and the reset line switch RST are each, for example, a thin film transistor. When the pixel switch SST is in the on state, the image signal Vsg is input from the image signal line VL to the pixel circuit.

[0087] The drive circuit 6 includes a shift register circuit, an output buffer circuit, and the like, which are not illustrated. The drive circuit 6 outputs a pulse on the basis of a horizontal scan start pulse transmitted from the control circuit 5 (refer to Figure 1 ), and outputs the control signal Gss, the control signal Gsb, and the control signal Gsr.

[0088] The plurality of scan signal lines GL include a scan signal line GLA, a scan signal line GLB, and a reset line GLR. The plurality of scan signal lines GL extend along the X direction. The scan signal line GLA is connected to the gate of the output switch BCT. When the scan signal line GLA is supplied with the control signal Gsb, the output switch BCT becomes in the on state. The scan signal line GLB is connected to the gate of the pixel switch SST. When the scan signal line GLB is supplied with the control signal Gss, the pixel switch SST becomes in the on state. The reset line GLR is connected between the output switch BCT and the drive transistor DRT, and is connected to the drain of the reset line switch RST. When the gate of the reset line switch RST is supplied with the control signal Gsr as a reset line signal, the reset line GLR is supplied with the reset line potential.

[0089] The pixel PIX has a holding capacitor Cs and an auxiliary capacitor Cad. The holding capacitor Cs and the auxiliary capacitor Cad are each a capacitor. The holding capacitor Cs is connected between the gate of the drive transistor DRT and the terminal 30H. The auxiliary capacitor Cad is connected between the source of the output switch BCT and the terminal 30H. The auxiliary capacitor Cad is a capacitive element for adjusting the amount of current of the light emission, and as a modification example, there is a case where the auxiliary capacitor Cad is not provided.

[0090] <Peripheral structure of LED element>

[0091] Next, the peripheral structure of the LED element provided in the pixel PIX illustrated in FIG. 1 is described. Figure 1 Figure 3 ​is an enlarged sectional view showing one example of a peripheral configuration of an LED element in a plurality of pixels of the display device shown in Figure 1 Figure 4 is an enlarged sectional view showing one example of a peripheral configuration of an LED element in a plurality of pixels of the display device shown in Figure 3

[0092] Figure 3 The array substrate SUB1 is a substrate including the substrate 10 and a plurality of insulating layers stacked on the substrate 10. The plurality of insulating layers of the array substrate SUB1 include an inorganic insulating layer 11, an organic insulating layer 12, and an organic insulating layer 13. In addition, the array substrate SUB1 includes various circuits provided in the pixel PIX described above. The substrate 10 has a surface 10f and a surface 10b on the opposite side of the surface 10f. The inorganic insulating layer 11, the organic insulating layer 12, and the organic insulating layer 13 are stacked on the surface 10f of the substrate 10, respectively. Figure 2

[0093] There are cases where each of the inorganic insulating layer 11, the organic insulating layer 12, and the organic insulating layer 13 is composed of a stacked film of a plurality of insulating films formed by stacking. For example, the inorganic insulating layer 11 is composed of a stacked film of a first inorganic insulating film 11a and a second inorganic insulating film 11b. Figure 2 The semiconductor layers of the thin film transistors that constitute the output switch BCT, the drive transistor DRT, and the pixel switch SST are formed in the inorganic insulating layer 11. A part of the plurality of inorganic insulating films that constitute the inorganic insulating layer 11 serves as a base layer for forming the thin film transistors, and the other part serves as a gate insulating film of the thin film transistors.

[0094] As shown in Figure 3 The LED element 20 is mounted on the array substrate SUB1. The LED element 20 has a surface 20f and a surface 20b on the opposite side of the surface 20f. In addition, the LED element 20 has a plurality of (two in the example shown in Figure 3 The plurality of electrodes 20E include an anode 20EA and a cathode 20EK. The anode 20EA is connected to the terminal 30H via a conductive bonding member 40. The cathode 20EK is connected to the terminal 30L via the conductive bonding member 40. The conductive bonding member 40 is composed of, for example, solder. In Figure 3 One LED element is exemplified in the example shown in

[0095] Note that, in Figure 3 In the example shown inFor example, in​​Figure 4 In the case of the LED element 20M1 shown, a cathode 20EK is provided on surface 20f, and an anode 20EA is provided on surface 20b. Figure 3 The LED element 20 shown is replaced with Figure 4 In the case of the LED element 20M1 shown, the terminal 30L connected to the cathode 20EK (refer to...) Figure 3 It is set on surface 20f of LED element 20M1.

[0096] <Manufacturing Method of LED Display Device>

[0097] Next, an explanation Figure 1 The manufacturing method of the display device DSP1 shown. Figure 5 It is shown Figure 1 A flowchart illustrating the manufacturing process of the display device is shown. Figure 5 In the illustrated process, the method of sequentially mounting three types of LED elements, such as red, green, and blue, on an array substrate is used as an example. However, as a variation, as described later, there is also a method of mounting multiple LED elements on an array substrate at once using a holding substrate in which multiple LED elements 20 are arranged in rows and columns.

[0098] <Processes for preparing LED holding substrates and processes for preparing array substrates>

[0099] exist Figure 5 In the process of preparing the LED holding substrate shown, the preparation Figure 6 The substrates SS1, SS2 and SS3 are shown. Figure 6 It is shown in Figure 5 The diagram shows a top view of the substrates prepared during the process of preparing the LED holding substrate. Substrates SS1, SS2, and SS3 each have an upper surface and a lower surface. Furthermore, substrates SS1, SS2, and SS3 each have a [missing information - likely referring to a specific feature or feature] on either the upper or lower surface (in [missing information - likely referring to a specific feature or feature]). Figure 6 In the example shown, multiple LED elements are arranged in rows and columns on the top surface.

[0100] In detail, different kinds of LED elements are arranged on the substrate SS1, the substrate SS2, and the substrate SS3, respectively. In other words, the substrate SS1, the substrate SS2, and the substrate SS3 are LED holding substrates each holding a plurality of LED elements. For example, on the upper surface SS1t of the substrate SS1, a first inorganic light emitting element 21 that is one of a red LED element, a green LED element, and a blue LED element is arranged. On the upper surface SS2t of the substrate SS2, a second inorganic light emitting element 22 that is an LED element different from the first inorganic light emitting element 21 among the red LED element, the green LED element, and the blue LED element is arranged. On the upper surface SS3t of the substrate SS3, a third inorganic light emitting element 23 that is an LED element different from the first inorganic light emitting element 21 and the second inorganic light emitting element 22 among the red LED element, the green LED element, and the blue LED element is arranged.

[0101] On the upper surface SS1t of the substrate SS1, a plurality of the first inorganic light emitting elements 21 are arranged in a matrix. On the upper surface SS1t of the substrate SS1, the second inorganic light emitting elements 22 and the third inorganic light emitting elements 23 are not arranged. On the upper surface SS2t of the substrate SS2, a plurality of the second inorganic light emitting elements 22 are arranged in a matrix. On the upper surface SS2t of the substrate SS2, the first inorganic light emitting elements 21 and the third inorganic light emitting elements 23 are not arranged. On the upper surface SS3t of the substrate SS3, a plurality of the third inorganic light emitting elements 23 are arranged in a matrix. On the upper surface SS3t of the substrate SS3, the first inorganic light emitting elements 21 and the second inorganic light emitting elements 22 are not arranged. The substrate SS1, the substrate SS2, and the substrate SS3 are, for example, sapphire substrates. Each of the first inorganic light emitting elements 21, the second inorganic light emitting elements 22, and the third inorganic light emitting elements 23 is formed by, for example, stacking a metal film, an insulating film, and a semiconductor film, and the like on a sapphire substrate.

[0102] Note that, in Figure 6 , the planar shapes of the substrate SS1, the substrate SS2, and the substrate SS3 are illustrated as circular, but the planar shapes of the substrate SS1, the substrate SS2, and the substrate SS3 are not limited to circular, and various modifications such as quadrilateral are present.

[0103] In the present embodiment, an embodiment in which all of the substrates SS1, the substrates SS2, and the substrates SS3 are prepared in advance and the thicknesses of all kinds of the substrates are measured in advance before the process of mounting the first LED elements is explained. In the case of this method, since the thicknesses of the first inorganic light emitting element 21, the second inorganic light emitting element 22, and the third inorganic light emitting element 23 are measured in advance, it is possible to start the mounting to the array substrate SUB1 from the substrate including the thinnest LED element (inorganic light emitting element) 20, and thus is preferable. However, as a modification example, there is also a case in which all of the substrates SS1, the substrates SS2, and the substrates SS3 are not prepared in advance before the process of mounting the first LED elements. For example, it is possible to prepare the substrates SS2 at least before the process of mounting the second LED elements and to measure the thicknesses. In addition, it is possible to prepare the substrates SS3 at least before the process of mounting the third LED elements and to measure the thicknesses.

[0104] In addition, in the process of preparing the array substrate, the array substrate SUB1 illustrated in FIG. 1 is prepared. Figure 7 Figure 7 is a cross-sectional view illustrating an outline of the array substrate SUB1 prepared in the process of preparing the array substrate illustrated in FIG. 1. As illustrated in FIG. 2, the array substrate SUB1 includes a surface SUBt and a surface SUBb on the opposite side of the surface SUBt. The surface SUBt is a surface on which the plurality of LED elements 20 illustrated in FIG. 1 are to be mounted. Figure 5 Figure 7 Figure 6

[0105] The array substrate SUB1 has a plurality of terminals 30. The plurality of terminals 30 includes a terminal (a first terminal) 31 that is to be electrically connected to the first inorganic light emitting element 21 (refer to FIG. 1). Figure 6 The plurality of terminals 30 includes a terminal (a second terminal) 32 that is to be electrically connected to the second inorganic light emitting element 22 (refer to FIG. 1). Figure 6 In addition, the plurality of terminals 30 includes a terminal (a third terminal) 33 that is to be electrically connected to the third inorganic light emitting element 23 (refer to FIG. 1). Figure 6 The terminals 31, the terminals 32, and the terminals 33 are arranged in a matrix shape corresponding to the positions of the pixels PIX illustrated in FIG. 1, respectively. Figure 1

[0106] The process of preparing the array substrate can be performed before the process of measuring the thicknesses illustrated in FIG. 3, and the order thereof with the process of preparing the holding substrate is not limited. For example, the process of preparing the holding substrate and the process of preparing the array substrate can be performed at the same time (in parallel). Figure 5

[0107] <Process of Measuring Thicknesses>

[0108] Next, the process of measuring the thicknesses illustrated in FIG. 3 is explained. Figure 5 Figure 8 ​​​​​​​is a schematic view Figure 5 is a cross-sectional view of an example of a measurement site in the process of measuring thickness. Figure 9 is a schematic view Figure 5 is an explanatory view of an example of a method of measuring thickness in the process of measuring thickness.

[0109] In this process, the thickness of the first LED element 21, the second LED element 22, and the third LED element 23 is measured. The thickness of the first LED element 21, the second LED element 22, and the third LED element 23 is measured in the process of measuring thickness described below. Figure 6 is data for controlling the amount of pressing of the substrate SS1, the substrate SS2, or the substrate SS3 against the array substrate SUB1. Therefore, in this process, the thickness of each portion is measured. Figure 7 is a cross-sectional view of an example of a measurement site in the process of measuring thickness. Figure 8 is a cross-sectional view of an example of a measurement site in the process of measuring thickness. Figure 7 is a cross-sectional view of an example of a measurement site in the process of measuring thickness. Figure 3 is a cross-sectional view of an example of a measurement site in the process of measuring thickness.

[0110] In this process, the thickness TSS1 of the substrate SS1 is measured. The thickness TSS1 of the substrate SS1 is the shortest distance between the upper surface SS1t and the lower surface SS1b of the substrate SS1. In this process, the thickness T21 of one or more of the first inorganic light emitting elements 21 arranged on the substrate SS1 is measured. The thickness T21 of the first inorganic light emitting element 21 is the shortest distance between the surface 20f and the surface 20b of the first inorganic light emitting element 21 or the shortest distance between the surface 20f and the surface of the electrode 20E facing the substrate SUB1. However, the shortest distance between the surface 20b of the first inorganic light emitting element 21 or the surface of the electrode 20E facing the substrate SUB1 and the lower surface SS1b of the substrate SS1 can be measured, and the difference from the thickness TSS1 of the substrate SS1 can be regarded as the thickness T21 of the first inorganic light emitting element 21. Figure 3 is a cross-sectional view of an example of a measurement site in the process of measuring thickness.

[0111] In this process, the thickness TSS2 of the substrate SS2 is measured. The thickness TSS2 of the substrate SS2 is the shortest distance between the upper surface SS2t and the lower surface SS2b of the substrate SS2. In this process, the thickness T22 of one or more of the second inorganic light emitting elements 22 arranged on the substrate SS2 is measured. The thickness T22 of the second inorganic light emitting element 22 is the shortest distance between the surface 20f and the surface 20b of the second inorganic light emitting element 22 or the shortest distance between the surface 20f and the surface of the electrode 20E facing the substrate SUB1. However, the shortest distance between the surface 20b of the second inorganic light emitting element 22 or the surface of the electrode 20E facing the substrate SUB1 and the lower surface SS2b of the substrate SS2 can be measured, and the difference from the thickness TSS2 of the substrate SS2 can be regarded as the thickness T22 of the second inorganic light emitting element 22. Figure 3The shortest distance between the face 20f and the face 20b, or the shortest distance between the face 20f and the face of the electrode 20E facing the substrate SUB1. However, the shortest distance between the face 20b or the face of the electrode 20E facing the substrate SUB1 of the second inorganic light emitting element 22 and the lower surface SS2b of the substrate SS2 can also be measured, and the difference between this measurement result and the thickness TSS2 of the substrate SS2 can be regarded as the thickness T22 of the second inorganic light emitting element 22.

[0112] In this process, the thickness TSS3 of the substrate SS3 is also measured. The thickness TSS3 of the substrate SS3 is the shortest distance between the upper surface SS3t and the lower surface SS3b of the substrate SS3. In this process, the thickness T23 of one or more of the plurality of third inorganic light emitting elements 23 arranged on the substrate SS3 is also measured. The thickness T23 of the third inorganic light emitting element 23 is the shortest distance between the face 20f and the face 20b, or the shortest distance between the face 20f and the face of the electrode 20E facing the substrate SUB1. However, the shortest distance between the face 20b or the face of the electrode 20E facing the substrate SUB1 of the third inorganic light emitting element 23 and the lower surface SS3b of the substrate SS3 can also be measured, and the difference between this measurement result and the thickness TSS3 of the substrate SS3 can be regarded as the thickness T23 of the third inorganic light emitting element 23. Figure 3

[0113] In this process, the thickness TSS1, the thickness TSS2, and the thickness TSS3 can also be measured at a plurality of positions, respectively. In this case, since the reliability of the measurement result is improved, the pressing force can be precisely controlled in the process of mounting the first LED element, the process of mounting the second LED element, and the process of mounting the third LED element, which will be described later. However, each of the plurality of LED elements 20 formed on one sapphire substrate is formed at the same time, so the thicknesses of the plurality of LED elements 20 formed on the same sapphire substrate are not likely to differ from each other. Therefore, if the work efficiency is considered, it is preferable to measure the thickness of one LED element of the plurality of LED elements 20 (for example, the thickness T21 of one first inorganic light emitting element 21 of the plurality of first inorganic light emitting elements 21, the thickness T22 of one second inorganic light emitting element 22 of the plurality of second inorganic light emitting elements 22, and the thickness T23 of one third inorganic light emitting element 23 of the plurality of third inorganic light emitting elements 23).

[0114] The method of measuring the thickness in this process is not particularly limited. However, the thickness of the LED element 20 is about 100 μm to 200 μm. Therefore, the measurement accuracy of the thickness in this process needs to measure in the order of μm. This is because, in the process of mounting the first LED element, the process of mounting the second LED element, and the process of mounting the third LED element, which will be described later, the pressing force is controlled in the order of μm. Figure 8 ​In a case where the thickness of each measurement site shown has a variation of several μm or so, adjustment of the pressing force is required.

[0115] As a method capable of measuring the thickness on the order of μm and capable of efficiently measuring the thickness, a method of measuring in a state where a workpiece (a measurement target) is sandwiched between two sensor heads can be exemplified. In the method, the distance from each of the sensor heads to the workpiece is measured, and the thickness of the workpiece is calculated from the difference between the distances. Figure 9 In the example shown, the workpiece 51 is arranged between the sensor head 50A and the sensor head 50B arranged so as to face each other. The workpiece 51 is arranged so as to face the sensor head 50A with the face 51t and so as to face the sensor head 50B with the face 51b. Figure 8 The array substrate SUB1, the substrate SS1, the substrate SS2, and the substrate SS3 shown correspond. Laser light 52 is irradiated from each of the sensor heads 50A and 50B toward the workpiece 51. By detecting the light reflected by the face 51t of the workpiece 51 by the sensor head 50A and the light reflected by the face 51b of the workpiece 51 by the sensor head 50B, respectively, the distance 53A from the sensor head 50A to the face 51t of the workpiece 51 and the distance 53B from the sensor head 50B to the face 51b of the workpiece 51 are measured. Since the separation distance 53C of the sensor head 50A from the sensor head 50B is set in advance, the value obtained by subtracting the distance 53A and the distance 53B from the separation distance 53C can be calculated as the thickness T51 of the workpiece 51.

[0116] However, as described above, the method of measuring the thickness can be implemented as long as the thickness measurement on the order of μm is possible, and in addition to the method shown, various modifications can be applied. For example, in a case where the workpiece 51 is a material having a property of transmitting the laser light 52, there is a method of measuring the light reflected by the face 51t and the face 51b of the workpiece 51, respectively, and calculating the measured thickness from the interference difference of the reflected light. In addition, for example, in the case of the above-described method, it is necessary to reflect the laser light 52 by the surface of the workpiece 51. Therefore, in a case where the workpiece 51 is a member that is difficult to reflect the laser light 52, there is a case where it is preferable to adopt another method. As another method, for example, a measurement method using ultrasonic waves or the like can be exemplified. Figure 9 <Installation of first LED element>

[0117] Next, the installation of the first LED element will be described.

[0118] Figure 5 The installation of the first LED element shown. Figure 10 is a cross-sectional view schematically showing a state where a substrate in which the first inorganic light-emitting element is arranged is pressed against the array substrate in the installation of the first LED element shown. Figure 5

[0119] ​​In the process of mounting the first LED elements, in a state in which the substrate SS1 held by the worktable 61 and the array substrate SUB1 held by the worktable 62 are opposed to each other, each of the plurality of first inorganic light emitting elements 21 is pressed against the array substrate SUB1, thereby electrically connecting the plurality of terminals 31 (see Figure 7 ) of the array substrate SUB1 and the plurality of first inorganic light emitting elements 21.

[0120] The worktable 61 is a member capable of holding the substrate SS1. The lower surface SS1b of the substrate SS1 is held by the holding surface 61h of the worktable 61. The worktable 62 is a member capable of holding the array substrate SUB1. The surface SUBb of the array substrate SUB1 is held by the holding surface 62h of the worktable 62. As a method of holding the substrate SS1 by the worktable 61 and a method of holding the array substrate SUB1 by the worktable 62, a method of adsorptive holding or a method of fixing the peripheral portion of the substrate SS1 or the array substrate SUB1 by a fixing jig not shown, and the like can be exemplified.

[0121] The holding surface 61h of the worktable 61 and the holding surface 62h of the worktable 62 are opposed to each other. Therefore, in a state in which the lower surface SS1b of the substrate SS1 is held by the holding surface 61h and the surface SUBb of the array substrate SUB1 is held by the holding surface 62h, as shown in Figure 10 , the upper surface SS1t of the substrate SS1 and the surface SUBt of the array substrate SUB1 are opposed to each other. In addition, the worktable 61 and the worktable 62 each have a mechanism capable of moving independently of each other in the planar direction (X-Y planar direction). In this process, at least one of the worktable 61 and the worktable 62 is moved along the X-Y planar direction to perform fine alignment so that the electrodes 20E (see Figure 3 ) provided in the plurality of first inorganic light emitting elements 21 are opposed to the terminals 31 (see Figure 3 ) of the array substrate SUB1, respectively. At this time, Figure 3 , the electrodes 20E have been joined to the conductive joining members 40. Therefore, when the alignment in the direction along the X-Y plane is performed, the terminals 31 become in a state of being opposed to the conductive joining members 40 joined to the electrodes 20E of the first inorganic light emitting elements 21.

[0122] In a state after the alignment in the direction along the above-described X-Y plane is performed, when the distance between the worktable 61 and the worktable 62 is made close, each of the plurality of first inorganic light emitting elements 21 disposed on the upper surface SS1t of the substrate SS1 is made close to the array substrate SUB1. At this time, Figure 3Each of the plurality of conductive bonding members 40 is in contact with the terminal 31 as illustrated. In this state, since the conductive bonding member 40 is bonded to the terminal 31 by performing, for example, a reflow soldering process (heating process), the electrode 20E of the first inorganic light emitting element 21 is electrically connected to the terminal 31 via the conductive bonding member 40.

[0123] Here, in order to connect the plurality of conductive bonding members 40 to the plurality of terminals 31, respectively, it is necessary to perform a reflow soldering process in a state where the contact surfaces of the conductive bonding members 40 and the terminals 31 are applied with appropriate load. For example, in a case where the pressing force with which the first inorganic light emitting element 21 is pressed against the array substrate SUB1 is insufficient, the conductive bonding member 40 and the terminal 31 are not well bonded, resulting in a decrease in electrical connection reliability. On the other hand, in a case where the pressing force with which the first inorganic light emitting element 21 is pressed against the array substrate SUB1 is excessive, there is a case where the first inorganic light emitting element 21 itself or a component in the periphery of the conductive bonding member 40 is damaged. Figure 3 The LED element 20 as illustrated is a micro LED element, and is small in outer dimensions. Therefore, in the case of the LED element 20, the thickness of the LED element 20 is likely to deviate from the design value by several μm or so. Figure 3 In the Z direction as illustrated, even in a case where the positional relationship of the conductive bonding member 40 and the terminal 31 deviates by several μm or so, there is a possibility that the above-described problem becomes significant. In particular, there is a case where the thickness of the LED element 21 deviates due to a difference in manufacturing conditions of the LED element 20. Therefore, in a case where the manufacturing lot is changed or the like, there is a case where the thickness of the LED element 20 deviates from the design value by, for example, several μm.

[0124] In the case of the present embodiment, as used in the description below, the process of measuring the thickness is performed before the process of mounting the first LED element. Figures 5-9 As described above, in the case of the present embodiment, the process of measuring the thickness is performed before the process of mounting the first LED element. Figure 8The thickness TSUB of the array substrate SUB1, the thickness TSS1 of the substrate SS1, and the thickness T21 of the first inorganic light emitting element 21 are shown. In the process of mounting the first LED element in this embodiment, the amount of pressing each of the plurality of first inorganic light emitting elements 21 against the array substrate SUB1 is controlled based on the results of measurement in the process of measuring the thickness. For example, in the case where the total of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS1 of the substrate SS1, and the thickness T21 of the first inorganic light emitting element 21 is less than the designed value, the control is performed in such a manner that the final separation distance after the approach of the stage 61 to the stage 62 is less than the value set in advance. That is, the amount of pressing the first inorganic light emitting element 21 against the array substrate SUB1 is reduced. The degree of reduction of the amount of pressing is determined based on the difference between the total of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS1 of the substrate SS1, and the thickness T21 of the first inorganic light emitting element 21 and the designed value. On the other hand, in the case where the total of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS1 of the substrate SS1, and the thickness T21 of the first inorganic light emitting element 21 is greater than the designed value, the control is performed in such a manner that the final separation distance after the approach of the stage 61 to the stage 62 is greater than the value set in advance. That is, the amount of pressing the first inorganic light emitting element 21 against the array substrate SUB1 is increased. The degree of increase of the amount of pressing is determined based on the difference between the total of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS1 of the substrate SS1, and the thickness T21 of the first inorganic light emitting element 21 and the designed value. Thus, it is possible to control the amount of pressing the first inorganic light emitting element 21 against the array substrate SUB1 to be appropriate, and to mount the first inorganic light emitting element 21 on the array substrate SUB1 with high accuracy. Figure 3 The contact surface of the conductive joint 40 and the terminal 31 is applied with an appropriate load in the state shown, and reflow soldering processing is performed. As a result, it is possible to improve the electrical connection reliability of the electrode 20E of the first inorganic light emitting element 21 and the terminal 31 via the conductive joint 40.

[0125] However, in the case where the thickness of the array substrate SUB1 is not uniform, the thickness of the substrate SS1 is not uniform, or the thickness of the first inorganic light emitting element 21 is not uniform, the amount of pressing the first inorganic light emitting element 21 against the array substrate SUB1 is not uniform. In this case, the first inorganic light emitting element 21 is pressed against the array substrate SUB1 in a non-uniform manner, and the first inorganic light emitting element 21 is not mounted on the array substrate SUB1 with high accuracy. Figure 10 In the example shown, the embodiment in which the pressing force is applied by pressing the stage 61 in the direction of the stage 62 is exemplified, but there are various modifications of the method of applying the pressing force. For example, there are a method of pushing the stage 62 in the direction of the stage 61, or a method of causing each of the stage 61 and the stage 62 to move in the Z direction, and the like.

[0126] <Process of peeling the first holding substrate>

[0127] Next, the process of peeling the first holding substrate is described. Figure 5 The process of peeling the first holding substrate is shown. Figure 11 is schematically shown in the process of peeling the first holding substrate. Figure 5The diagram shows a cross-sectional view of the holding substrate being peeled from the plurality of first inorganic light-emitting elements during the process of peeling off the first holding substrate. In the process of peeling off the first holding substrate, as shown... Figure 11 As shown, after the process of installing the first LED element, the substrate SS1 is peeled off from the plurality of first inorganic light-emitting elements 21.

[0128] Regarding the method of peeling the upper surface SS1t of the substrate SS1, which serves as the holding substrate, from the interface between the substrate SS1 and the plurality of first inorganic light-emitting elements 21, a technique known as laser peeling can be used, for example. When using the laser peeling technique, an ultraviolet laser, for example, is irradiated from the lower surface SS1b side of the substrate SS1 towards the interface between the upper surface SS1t of the substrate SS1 and the plurality of first inorganic light-emitting elements 21. The surface 20b of the first inorganic light-emitting element 21 (refer to...) Figure 3 A gallium nitride layer is formed thereon. When an ultraviolet laser is irradiated onto the surface 20b of the first inorganic light-emitting element 21, the surface layer of the gallium nitride layer (a portion of the surface 20b side) is modified, enabling the substrate SS1 to be peeled off from the first inorganic light-emitting element 21.

[0129] Through this process, a structure with multiple first inorganic light-emitting elements 21 mounted on the array substrate SUB1 is obtained.

[0130] <Procedure for installing the second LED component>

[0131] Next, an explanation Figure 5 The procedure for installing the second LED element is shown. Figure 12 It is shown schematically in Figure 5 The diagram shows a cross-sectional view of the substrate on which the second inorganic light-emitting elements are arranged and the array substrate pressed together during the process of mounting the second LED element.

[0132] In the process of installing the second LED element, with the substrate SS2 held on the worktable 61 and the array substrate SUB1 held on the worktable 62 facing each other, the multiple terminals 32 of the array substrate SUB1 (see reference) are pressed against each of the multiple second inorganic light-emitting elements 22, thereby securing them together. Figure 7 It is electrically connected to multiple second inorganic light-emitting elements 22.

[0133] The lower surface SS2b of substrate SS2 is held on the holding surface 61h of stage 61. Stage 62 is a component capable of holding array substrate SUB1. Array substrate SUB1, which has been equipped with a plurality of first inorganic light-emitting elements 21, is held on the holding surface 62h of stage 62 with surface SUBb side. As described above, there are various methods for stage 61 to hold substrate SS2 and for stage 62 to hold array substrate SUB1.

[0134] The holding surface 61h of the worktable 61 and the holding surface 62h of the worktable 62 are opposite to each other. Therefore, with the lower surface SS2b of the substrate SS2 held on the holding surface 61h and the surface SUBb of the array substrate SUB1 held on the holding surface 62h, as Figure 12 As shown, the upper surface SS2t of substrate SS2 faces the surface SUBt of array substrate SUB1. As described above, each of worktables 61 and 62 has a mechanism capable of independently moving along a planar direction (XY plane direction). In this process, at least one of worktables 61 and 62 is moved along the XY plane direction for precise alignment, so that the electrodes 20E (refer to...) of the plurality of second inorganic light-emitting elements 22... Figure 3 Each of the terminals 32 in the array substrate SUB1 (refer to) Figure 3 () Opposite. At this time, Figure 3 The electrode 20E shown has been bonded to the conductive connector 40. Therefore, when alignment is performed along the XY plane, the terminal 32 is positioned opposite the conductive connector 40 bonded to the electrode 20E of the second inorganic light-emitting element 22.

[0135] After alignment along the XY plane, when the distance between worktable 61 and worktable 62 is brought close, each of the plurality of second inorganic light-emitting elements 22 disposed on the upper surface SS2t of substrate SS2 approaches the array substrate SUB1. At this time, Figure 3 Each of the plurality of conductive connectors 40 shown is in contact with the terminal 32. Since the conductive connectors 40 are bonded to the terminal 32 by, for example, a reflow soldering process (heat treatment) in this state, the electrode 20E of the second inorganic light-emitting element 22 is electrically connected to the terminal 32 via the conductive connectors 40.

[0136] In this embodiment, a thickness measurement process is performed before the process of mounting the second LED element. Figure 8The thickness TSUB of the array substrate SUB1, the thickness TSS2 of the substrate SS2, and the thickness T22 of the second inorganic light emitting element 22 are measured. In the process of mounting the second LED element in the present embodiment, the amount of pressing each of the plurality of second inorganic light emitting elements 22 against the array substrate SUB is controlled based on the results of measurement in the process of measuring the thickness. For example, in the case where the total value of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS2 of the substrate SS2, and the thickness T22 of the second inorganic light emitting element 22 is less than the designed value, the control is performed in such a manner that the final separation distance after the approach of the stage 61 to the stage 62 is less than the value set in advance. That is, the amount of pressing the second inorganic light emitting element 22 against the array substrate SUB1 is reduced. The degree of reduction of the amount of pressing is determined based on the difference between the total value of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS2 of the substrate SS2, and the thickness T22 of the second inorganic light emitting element 22 and the designed value. On the other hand, in the case where the total value of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS2 of the substrate SS2, and the thickness T22 of the second inorganic light emitting element 22 is greater than the designed value, the control is performed in such a manner that the final separation distance after the approach of the stage 61 to the stage 62 is greater than the value set in advance. That is, the amount of pressing the second inorganic light emitting element 22 against the array substrate SUB1 is increased. The degree of increase of the amount of pressing is determined based on the difference between the total value of the measurement results of the thickness TSUB of the array substrate SUB1, the thickness TSS2 of the substrate SS2, and the thickness T22 of the second inorganic light emitting element 22 and the designed value. Thus, it is possible to Figure 3 The contact surface of the conductive joint 40 with the terminal 32 is applied with an appropriate load in the reflow soldering process. As a result, it is possible to improve the electrical connection reliability of the electrode 20E of the second inorganic light emitting element 22 with the terminal 32 via the conductive joint 40.

[0137] In addition, it is preferable that the thickness T21 (see Figure 8 ) of each of the plurality of first inorganic light emitting elements 21 be less than the thickness T22 (see Figure 8 ) of each of the plurality of second inorganic light emitting elements 22. The process of mounting the second LED element is performed in a state where the plurality of first inorganic light emitting elements 21 have already been mounted on the array substrate SUB1. Therefore, in the present process, from the viewpoint of suppressing damage to the plurality of first inorganic light emitting elements 21 sandwiched between the substrate SS2 and the array substrate SUB1, it is particularly preferable that the thickness T21 be less than the thickness T22.

[0138] <Process of peeling the second holding substrate>

[0139] Next, the process of peeling the second holding substrate will be described. Figure 5 <Process of peeling the second holding substrate> Figure 13 is a view showing theFigure 5 A cross-sectional view of a state in which the second holding substrate is peeled from the plurality of second inorganic light emitting elements in the process of peeling the second holding substrate is shown. In the process of peeling the second holding substrate, as shown in Figure 13 After the process of mounting the second LED elements, the substrate SS2 is peeled from the plurality of second inorganic light emitting elements 22. The method of peeling the upper surface SS2t of the substrate SS2 serving as the holding substrate from the adhesion interface of the plurality of second inorganic light emitting elements 22 is the same as the process of peeling the first holding substrate described above, and for example, a technique called laser peeling can be used. By this process, a configuration in which the plurality of first inorganic light emitting elements 21 and the plurality of second inorganic light emitting elements 22 are mounted on the array substrate SUB1 can be obtained.

[0140] <Process of mounting third LED elements>

[0141] Next, the process of mounting the third LED elements is described. Figure 5 A cross-sectional view of the process of mounting the third LED elements is shown. Figure 14 is a cross-sectional view schematically showing a state in which the substrate in which the third inorganic light emitting elements are arranged is pressed against the array substrate in the process of mounting the third LED elements shown in Figure 5

[0142] In the process of mounting the third LED elements, by pressing each of the plurality of third inorganic light emitting elements 23 against the array substrate SUB1 in a state in which the substrate SS3 held by the worktable 61 and the array substrate SUB1 held by the worktable 62 are opposed, the plurality of terminals 33 (refer to Figure 7 ) of the array substrate SUB1 and the plurality of third inorganic light emitting elements 23 are electrically connected.

[0143] The lower surface SS3b of the substrate SS3 is held by the holding surface 61h of the worktable 61. The worktable 62 is a member capable of holding the array substrate SUB1. The array substrate SUB1 having mounted thereon the plurality of first inorganic light emitting elements 21 and the plurality of second inorganic light emitting elements 22 holds the face SUBb side by the holding surface 62h of the worktable 62. The method of holding the substrate SS3 by the worktable 61 and the method of holding the array substrate SUB1 by the worktable 62 are as described above, and there are a variety of methods.

[0144] The holding surface 61h of the worktable 61 and the holding surface 62h of the worktable 62 are opposed to each other. Therefore, in a state in which the lower surface SS3b of the substrate SS3 is held by the holding surface 61h and the face SUBb of the array substrate SUB1 is held by the holding surface 62h, as shown in Figure 14 ​As shown, the upper surface SS3t of the substrate SS3 opposes the surface SUBt of the array substrate SUB1. As described above, each of the stages 61 and 62 is provided with a mechanism that enables independent movement in the planar direction (X-Y planar direction). In this process, at least one of the stages 61 and 62 is moved in the X-Y planar direction to perform precise alignment so that each of the electrodes 20E (see FIG. 6) provided in the plurality of third inorganic light emitting elements 23 opposes the terminal 33 (see FIG. 6) of the array substrate SUB1. At this time, as shown in FIG. 6, each of the plurality of conductive members 40 has already been joined to the electrode 20E. Figure 3 ) provided in the plurality of third inorganic light emitting elements 23 opposes the terminal 33 (see Figure 3 ) of the array substrate SUB1. At this time, Figure 3 the electrode 20E shown has been joined to the conductive member 40. Therefore, when alignment in the direction along the X-Y plane is performed, the terminal 33 becomes in a state of opposing the conductive member 40 joined to the electrode 20E of the third inorganic light emitting element 23.

[0145] In a state after alignment in the direction along the X-Y plane is performed, when the distance between the stages 61 and 62 is made close, each of the plurality of third inorganic light emitting elements 23 disposed on the upper surface SS3t of the substrate SS3 is brought close to the array substrate SUB1. At this time, Figure 3 each of the plurality of conductive members 40 shown contacts the terminal 33. Since the conductive member 40 is joined to the terminal 33 by performing, for example, a reflow soldering process (heating process) in this state, the electrode 20E of the third inorganic light emitting element 23 is electrically connected to the terminal 33 via the conductive member 40.

[0146] In the case of the present embodiment, the process of measuring the thickness is performed before the process of mounting the third LED element, and the thickness of the conductive member 40 is measured. Figure 8The thicknesses shown are TSUB of the array substrate SUB1, TSS3 of the substrate SS3, and T23 of the third inorganic light-emitting element 23. Furthermore, in the process of mounting the third LED element in this embodiment, the pressing amount of each of the multiple third inorganic light-emitting elements 23 against the array substrate SUB is controlled based on the measurement results from the thickness measurement process. For example, if the total value of the measured results of the thicknesses TSUB of the array substrate SUB1, TSS3 of the substrate SS3, and T23 of the third inorganic light-emitting element 23 is less than the design value, control is performed such that the final separation distance after the worktable 61 and worktable 62 approach is less than a preset value. That is, the pressing amount of the third inorganic light-emitting element 23 against the array substrate SUB1 is reduced. The degree of reduction in pressing amount is determined based on the difference between the total value of the measured results of the thicknesses TSUB of the array substrate SUB1, TSS3 of the substrate SS3, and T23 of the first inorganic light-emitting element 23 and the design value. On the other hand, if the total value of the measured results of the thickness TSUB of the array substrate SUB1, the thickness TSS3 of the substrate SS3, and the thickness T23 of the third inorganic light-emitting element 23 is greater than the design value, control is implemented in a way that the final separation distance after the worktable 61 and the worktable 62 approach each other is greater than a preset value. That is, the pressing amount that presses the third inorganic light-emitting element 23 against the array substrate SUB1 is increased. The degree of increase in pressing amount is based on the difference between the total value of the measured results of the thickness TSUB of the array substrate SUB1, the thickness TSS3 of the substrate SS3, and the thickness T23 of the third inorganic light-emitting element 23 and the design value. As a result, it is possible to Figure 3 The conductive connector 40 and the contact surface of the terminal 33 are subjected to appropriate load during reflow soldering. As a result, the reliability of the electrical connection between the electrode 20E of the third inorganic light-emitting element 23 and the terminal 33 via the conductive connector 40 can be improved.

[0147] In addition, the thickness T21 of each of the plurality of first inorganic light-emitting elements 21 is preferably (refer to) Figure 8 The thickness T23 of each of the multiple third inorganic light-emitting elements 23 (refer to) Figure 8 Below that. Furthermore, the thickness T22 of each of the plurality of second inorganic light-emitting elements 22 is preferably (refer to...). Figure 8 The thickness T23 of each of the multiple third inorganic light-emitting elements 23 is less than or equal to the thickness T23. The process of mounting the third LED elements is performed while the array substrate SUB1 already has multiple first inorganic light-emitting elements 21 and multiple second inorganic light-emitting elements 22 mounted on it. Therefore, in this process, from the viewpoint of suppressing damage to the multiple first inorganic light-emitting elements 21 and multiple second inorganic light-emitting elements 22 sandwiched between the substrate SS3 and the array substrate SUB1, it is particularly preferable that both the thickness T21 and the thickness T22 are less than the thickness T23.

[0148] <Process of peeling off the third holding substrate>

[0149] Next, an explanation Figure 5 The process shown is the peeling off of the third holding substrate. Figure 15 It is shown schematically in Figure 5 The diagram shows a cross-sectional view of the holding substrate being peeled from the plurality of third inorganic light-emitting elements during the process of peeling off the third holding substrate. In the process of peeling off the third holding substrate, as... Figure 13 As shown, after the process of mounting the third LED element, the substrate SS3 is peeled off from the plurality of third inorganic light-emitting elements 23. The method for peeling the upper surface SS3t of the substrate SS3 (which serves as the holding substrate) from the interface between the plurality of third inorganic light-emitting elements 23 is the same as the process of peeling off the first holding substrate described above; for example, a technique called laser peeling can be used. Through this process, a structure is obtained in which a plurality of first inorganic light-emitting elements 21, a plurality of second inorganic light-emitting elements 22, and a plurality of third inorganic light-emitting elements 23 are mounted on the array substrate SUB1. After this process, a protective film or the like is formed as needed to protect the plurality of LED elements 20, resulting in... Figure 1 The display device shown.

[0150] As described above, according to this embodiment, measurements are taken before mounting the plurality of LED elements (inorganic light-emitting elements) 20 onto the array substrate SUB1. Figure 8 The thickness TSUB of the array substrate SUB1, the thicknesses of the holding substrates (substrates SS1, SS2, and SS3) (thicknesses TSS1, TSS2, and TSS3), and the thicknesses of the LED element 20 (thicknesses T21, T22, and T23) allow for precise control of the clamping force during mounting. As a result, the reliability of the electrical connection between the LED element 20 and the array substrate SUB1 can be improved.

[0151] It should be noted that, in Figure 5 The example shown illustrates an implementation where three types of LED components are installed sequentially, but the types of LED components installed are not limited to three. For example, if only one type of LED component needs to be installed at a time, it can be omitted. Figure 5 The process shown is from mounting the second LED element to peeling off the third holding substrate. Furthermore, for example, in a manufacturing method for a display device that mounts two types of LED elements, the process can be omitted. Figure 5 The process shown is from mounting the third LED element to peeling off the third holding substrate. Furthermore, in the manufacturing method of a display device that mounts four or more types of LED elements, by... Figure 5The LED element mounting process and the holding substrate peeling process are repeatedly performed after the illustrated process of peeling the third holding substrate, and different LED elements from the first to third LED elements are mounted, thereby obtaining.

[0152] <Modification example of holding substrate>

[0153] As another modification example of the above-described Figure 5 There is a case where a plurality of (for example, three) kinds of LED elements are mounted on the array substrate SUB1. The modification example will be described below. Figure 16 is a modification example of the above-described Figure 10 is a cross-sectional view schematically showing a state before mounting the holding substrate on which a plurality of kinds of LED elements are held, on the array substrate.

[0154] Figure 16 The substrate SS4 has an upper surface SS4t and a lower surface SS4b. A plurality of LED elements 20 including a plurality of first inorganic light emitting elements 21, a plurality of second inorganic light emitting elements 22, and a plurality of second inorganic light emitting elements 22 are arranged in a matrix on the upper surface SS4t of the substrate SS4. The substrate SS4 is a support substrate and is not a substrate for manufacturing the LED elements 20, and thus a sapphire substrate need not be used. For example, a glass substrate or the like can be used. The plurality of LED elements 20 are adhesively fixed to the upper surface SS4t of the substrate SS4 with an adhesive layer not shown.

[0155] The method of arranging the plurality of LED elements 20 on the upper surface SS4t of the substrate SS4 can apply, for example, the method of sequentially mounting the first inorganic light emitting elements 21, the second inorganic light emitting elements 22, and the third inorganic light emitting elements 23 on the array substrate SUB1 as illustrated in FIG. 6. Figure 8 In the case where the LED elements 20 are adhesively fixed to the substrate SS4, the process of measuring the thickness can be omitted because electrical connection or the like is not required. However, in the case where the substrate SS4 is pressed against the array substrate SUB1 in the LED mounting process, the process of measuring the thickness is required.

[0156] In the case of the present modification example, in the process of measuring the thickness, the thickness of the plurality of LED elements 20 is preferably measured so that the thinnest LED element 20 and the thickest LED element 20 among the plurality of LED elements 20 can be detected. By measuring the thinnest LED element 20 and the thickest LED element 20, the margin allowed for the pressing force value can be calculated in the LED element mounting process.

[0157] In the case of the present modification example, because a plurality of kinds of LED elements 20 are mounted on the array substrate SUB1, the time required for the LED element mounting process is longer than that of the above-described Figure 5The example shown can be shortened. However, the thickness of the LED element 20 varies depending on the type, and from the viewpoint of improving the electrical connection reliability of the LED element 20 and the terminal 30 (see FIG. 8) Figure 3 ), it is preferable to use the manufacturing method exemplified in Figure 5

[0158] The above describes the embodiments and representative modifications, but the above-described technology can be applied to various modifications other than the exemplified modifications. For example, the above-described modifications can be combined with each other.

[0159] Those skilled in the art can conceive various modifications and corrections within the scope of the idea of the present application, and it is understood that these modifications and corrections also belong to the scope of the present application. For example, a mode obtained by appropriately adding, deleting, or designing changing the constituent elements, or adding, omitting, or conditionally changing the processes with respect to each of the above-described embodiments by those skilled in the art, as long as the gist of the present application is possessed, is included in the scope of the present application.

[0160] Industrial Applicability

[0161] The present application can be applied to a display device, an electronic device assembled with the display device.​

Claims

1. A method for manufacturing a display device, comprising the following steps: (a) A process of preparing a first substrate having a plurality of first inorganic light-emitting elements arranged in rows and columns, and an array substrate having a plurality of first terminals formed thereon; (b) A process of measuring the thickness of the first substrate, the thickness of one or more of the plurality of first inorganic light-emitting elements, and the thickness of the array substrate. (c) A step of electrically connecting the plurality of first terminals of the array substrate to the plurality of first inorganic light-emitting elements by pressing each of the plurality of first inorganic light-emitting elements against the array substrate while the first substrate held on the first worktable is facing the array substrate; and (d) The step of peeling the first substrate from the plurality of first inorganic light-emitting elements after step (c). in, In step (c), the pressing amount of each of the plurality of first inorganic light-emitting elements against the array substrate is controlled based on the measurement results in step (b).

2. The method for manufacturing a display device according to claim 1, wherein, A plurality of second terminals are further formed on the array substrate prepared in step (a), and the manufacturing method includes: (e) A process for preparing a second substrate having multiple second inorganic light-emitting elements arranged in rows and columns; (f) A process of measuring the thickness of one or more of the plurality of second inorganic light-emitting elements and the thickness of the second substrate; (g) After steps (d), (e) and (f), in a state where the second substrate held on the first worktable and the array substrate held on the second worktable are facing each other, the plurality of second terminals of the array substrate are electrically connected to the plurality of second inorganic light-emitting elements by pressing each of the plurality of second inorganic light-emitting elements against the array substrate. and (h) The step of peeling the second substrate from the plurality of second inorganic light-emitting elements after step (g). In step (g), the pressing amount of each of the plurality of second inorganic light-emitting elements against the array substrate is controlled based on the results measured in steps (b) and (f).

3. The method for manufacturing a display device according to claim 2, wherein, A plurality of third terminals are further formed on the array substrate prepared in step (a), and the manufacturing method includes: (i) A process for preparing a third substrate having multiple third inorganic light-emitting elements arranged in rows and columns; (k) A process of measuring the thickness of one or more of the plurality of third inorganic light-emitting elements and the thickness of the third substrate; (m) After the (h) step, the (i) step and the (k) step, in a state where the third substrate held on the first worktable and the array substrate held on the second worktable are facing each other, the plurality of third inorganic light-emitting elements are pressed against the array substrate, thereby electrically connecting the plurality of third terminals of the array substrate to the plurality of third inorganic light-emitting elements. and (n) The step of peeling the third substrate from the plurality of third inorganic light-emitting elements after the (m) step. In step (m), the pressing amount of each of the plurality of third inorganic light-emitting elements against the array substrate is controlled based on the results measured in steps (b) and (k).

4. The method for manufacturing a display device according to claim 3, wherein, Each of steps (e), (f), (i), and (k) is performed before step (c). The thickness of the first inorganic light-emitting element measured in step (b) is thinner than the thickness of the second inorganic light-emitting element measured in step (f) and the thickness of the third inorganic light-emitting element measured in step (k). The thickness of the second inorganic light-emitting element measured in step (f) is thinner than the thickness of the third inorganic light-emitting element measured in step (k).

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