Film-like anisotropic conductive adhesive layer, anisotropic conductive adhesive layer substrate, and lifting method

Abstract

The present invention provides a method for manufacturing a display device that can shorten the cycle time. [Solution] The method comprises a transfer step in which an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light is placed opposite a wiring substrate, and laser light is irradiated from the substrate side to transfer and arrange individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate, and a mounting step in which light-emitting elements are mounted on the individual pieces arranged at predetermined positions on the wiring substrate. By irradiating with laser light, individual pieces of the anisotropic conductive adhesive layer can be transferred and arranged with high precision and efficiency.

Description

[Technical Field]

[0001] This technology relates to a method for manufacturing a display device comprising an array of light-emitting elements. More particularly, it relates to a method for manufacturing a display device comprising an array of LED elements such as mini-LEDs and micro-LEDs. This application claims priority based on Japanese Patent Application No. 2021-054138, filed in Japan on March 26, 2021, which is incorporated herein by reference. [Background technology]

[0002] Conventionally, display devices have been proposed that constitute a light-emitting array by arranging multiple light-emitting elements such as LEDs (Light Emitting Diodes). Patent Document 1 discloses a method for joining LEDs with an anisotropic conductive adhesive such as ACF (Anisotropic Conductive Film).

[0003] In the manufacturing method described in Patent Document 1, the ACF is attached to the element mounting surface of the substrate all at once, so the adhesive resin and conductive particles of the ACF remain between each LED pitch. Therefore, when light transmittance is required for the light-emitting element array, it hinders light transmission and makes it impossible to obtain excellent light transmittance.

[0004] On the other hand, if the ACF is only attached directly below the LED, the attachment process alone will take a considerable amount of time, worsening the cycle time. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2015 / 0255505 [Overview of the project] [Problems that the invention aims to solve]

[0006] This technology was proposed in light of the conventional situation described above, and provides a method for manufacturing a display device that can shorten the cycle time. [Means for solving the problem]

[0007] A method for manufacturing a display device according to this technology includes a transfer step in which an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light is placed opposite a wiring substrate, and laser light is irradiated from the substrate side to transfer and arrange individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate, and a mounting step in which light-emitting elements are mounted on the individual pieces arranged at predetermined positions on the wiring substrate.

[0008] A method for manufacturing a display device according to this technology includes a transfer step of placing an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light and light-emitting elements arranged on a transfer substrate opposite each other, and irradiating the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate; a re-transfer step of re-transferring the light-emitting elements onto the wiring substrate with the transferred individual pieces; and a mounting step of mounting the light-emitting elements arranged at predetermined positions on the wiring substrate via the individual pieces. [Effects of the Invention]

[0009] This technology allows for the high-precision and high-efficiency transfer and arrangement of individual pieces of anisotropic conductive adhesive layer by laser irradiation, thereby shortening the cycle time. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing an anisotropic conductive adhesive layer provided on a substrate and a wiring board facing each other. [Figure 2] Figure 2 is a schematic cross-sectional view showing the state in which individual pieces of anisotropic conductive adhesive layer are transferred to predetermined positions on a wiring board and arranged by irradiating them with laser light from the substrate side. [Figure 3]FIG. 3 is a cross-sectional view schematically showing a state where light-emitting elements are mounted on individual pieces arranged at predetermined positions on a wiring board. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a state where laser light is irradiated from the substrate side, and individual pieces of an anisotropic conductive adhesive layer are transferred and arranged at electrode positions on a wiring board. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a state where light-emitting elements are mounted on individual pieces arranged in electrode units on a wiring board. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a state where an anisotropic conductive adhesive layer provided on a base material is opposed to light-emitting elements arranged on a transfer substrate. [Figure 7] FIG. 7 is a cross-sectional view schematically showing an anisotropic conductive adhesive layer provided on a base material. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a state where laser light is irradiated from the base material side, and individual pieces of an anisotropic conductive adhesive layer are transferred onto light-emitting elements arranged on a transfer substrate. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a state where a light-emitting element onto which individual pieces are transferred is re-transferred onto a wiring board. [Figure 10] FIG. 10 is a metal microscope photograph showing individual pieces of an anisotropic conductive adhesive layer arranged on a bare glass. [Figure 11] FIG. 11 is an enlarged photograph of the metal microscope photograph shown in FIG. 4.

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present technology will be described in detail in the following order with reference to the drawings. 1. Method for manufacturing a display device 2. Examples

[0012] <1. Method for manufacturing a display device> [First Embodiment] The manufacturing method of the display device according to the first embodiment includes an alignment step of facing an anisotropic conductive adhesive layer provided on a substrate having transparency to laser light and a wiring substrate, irradiating laser light from the substrate side to transfer and align individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate, and a mounting step of mounting a light-emitting element on the individual pieces arranged at the predetermined positions on the wiring substrate. Since the individual pieces of the anisotropic conductive adhesive layer can be transferred and aligned with high precision and high efficiency by irradiation with laser light, the tact time can be shortened.

[0013] Hereinafter, referring to FIGS. 1 to 3, the alignment step (A) of transferring and aligning individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate and the mounting step (B) of mounting a light-emitting element on the individual pieces arranged at the predetermined positions on the wiring substrate will be described.

[0014] [Alignment Step (A)] FIG. 1 is a cross-sectional view schematically showing a state in which an anisotropic conductive adhesive layer provided on a substrate and a wiring substrate are opposed to each other. As shown in FIG. 1, first, in the alignment step (A), the anisotropic conductive adhesive layer substrate 10 and the wiring substrate 20 are opposed to each other.

[0015] The anisotropic conductive adhesive layer substrate 10 includes a substrate 11 and an anisotropic conductive adhesive layer 12, and the anisotropic conductive adhesive layer 12 is provided on the surface of the substrate 11. The substrate 11 may be any substrate having transparency to laser light, and among them, quartz glass having a high light transmittance over the entire wavelength is preferably used.

[0016] The anisotropic conductive adhesive layer 12 contains conductive particles 13 in a binder, for example. Furthermore, from the viewpoint of laser transferability, the anisotropic conductive adhesive layer 12 is preferably configured such that the conductive particles 13 are captured in a planar direction to achieve conductivity and short circuits are avoided. The alignment of the conductive particles is preferably in a regular arrangement. One example is Japanese Patent No. 6119718. Examples of binders include epoxy adhesives and acrylic adhesives, and among these, epoxy adhesives containing resins with a maximum absorption wavelength of 180 nm to 360 nm or high-purity bisphenol A type epoxy resin can be preferably used. A specific example of a high-purity bisphenol A type epoxy resin is, for example, the product name "YL980" manufactured by Mitsubishi Chemical Corporation. Furthermore, as the epoxy resin curing agent contained in the epoxy adhesive, for example, cationic polymerization initiators such as aromatic sulfonium salts or anionic polymerization initiators can be preferably used. A specific example of an aromatic sulfonium salt type cationic polymerization initiator is, for example, the product name "SI-60L" manufactured by Sanshin Chemical Industry Co., Ltd. Furthermore, acrylic adhesives are adhesives that utilize radical polymerization reactions and contain, for example, radical polymerizable substances such as (meth)acrylate compounds and radical polymerization initiators such as peroxides. From the viewpoint of heat resistance and adhesion required when used in display devices, epoxy adhesives are preferable. Although a thermosetting anisotropic conductive adhesive layer has been described here, a photocuring anisotropic conductive adhesive layer may be used if heat needs to be avoided in later processes. In that case, a photopolymerization initiator can be used instead of the aforementioned thermopolymerization initiator.

[0017] As the conductive particles 13, those used in known anisotropic conductive films can be appropriately selected and used. For example, nickel (melting point 1455°C), copper (melting point 1085°C), silver (melting point 961.8°C), gold (melting point 1064°C), palladium (melting point 1555°C), tin (melting point 231.9°C), nickel boride (melting point 1230°C), ruthenium (melting point Examples include metal-coated resin particles, in which the surface of resin particles such as tin alloy solder (2334°C), polyamide, polybenzoguanamine, styrene, and divinylbenzene is coated with a metal such as nickel, copper, silver, gold, palladium, tin, nickel boride, or ruthenium; and metal-coated inorganic particles, in which the surface of inorganic particles such as silica, alumina, barium titanate, zirconia, carbon black, silicate glass, borosilicate glass, lead glass, soda-lime glass, and alumina silicate glass is coated with a metal such as nickel, copper, silver, gold, palladium, tin, nickel boride, or ruthenium. The metal particles may be coated with the aforementioned metals. Furthermore, the metal layer in the metal-coated resin particles and metal-coated inorganic particles may be a single layer or formed from multiple layers of different metals.

[0018] These conductive particles can be coated with insulating particles, such as a resin layer, resin particles, or inorganic particles, to provide an insulating coating. The particle size of the conductive particles 13 is appropriately changed depending on the area of ​​the electrodes and bumps of the optical element or wiring board to be mounted, but is preferably 1 to 30 μm, more preferably 1 to 10 μm, and particularly preferably 1 to 3 μm. When used for mounting micro-LED elements, the area of ​​the electrodes and bumps is small, so the particle size is preferably 1 to 2.5 μm, more preferably 1 to 2.2 μm, and particularly preferably 1 to 2 μm. The particle size can be determined by measuring 200 or more particles using a microscope (optical microscope, metallurgical microscope, electron microscope, etc.) and calculating the average particle size.

[0019] Furthermore, in conductive particles in which resin particles or inorganic particles are coated with metal as described above, the thickness of the metal coating is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 0.3 μm or less. This coating thickness is the total thickness of the metal coating when the metal coating is multi-layered. When this coating thickness is above the lower limit and below the upper limit, sufficient conductivity is easily obtained, and the conductive particles do not become too hard, making it easier to utilize the properties of the resin particles or inorganic particles as described above.

[0020] The above coating thickness can be measured, for example, by observing the cross-section of the conductive particles using a transmission electron microscope (TEM). Preferably, the coating thickness is calculated by taking the average of five arbitrary coating thickness values ​​as the coating thickness of a single conductive particle, and more preferably, by taking the average of the thickness of the entire coated area as the coating thickness of a single conductive particle. Preferably, the above coating thickness is determined by calculating the average value of the coating thickness of each conductive particle for 10 arbitrary conductive particles.

[0021] Furthermore, conductive particles can take various shapes, including spherical, ellipsoidal, spike-shaped, and irregular shapes. Among these, spherical conductive particles are preferred because their particle size and particle size distribution are easily controllable. These conductive particles may have protrusions on their surface to improve connectivity.

[0022] The thickness of the anisotropic conductive adhesive layer is appropriately changed depending on the height of the electrodes and bumps of the mounted optical element or wiring board, but is preferably 1 to 30 μm, and more preferably 1 to 10 μm. When used for mounting micro-LED elements, the height of the electrodes and bumps is low, so this thickness is preferably 1 to 6 μm, more preferably 1 to 5 μm, and particularly preferably 1 to 4 μm.

[0023] By making the anisotropic conductive adhesive layer into a film, it becomes easier to apply the anisotropic conductive adhesive layer to the substrate. From the viewpoint of ease of handling, it is preferable that a release film such as polyethylene terephthalate film is provided on one or both sides of the anisotropic conductive adhesive layer.

[0024] These anisotropic conductive adhesive layers can be laminated onto a substrate by transferring the anisotropic conductive adhesive layer onto the substrate, or they can be laminated onto the substrate by manufacturing the anisotropic conductive adhesive layer on the substrate. Methods for manufacturing an anisotropic conductive adhesive layer on a substrate include, for example, applying and drying a solution of anisotropic conductive adhesive onto the substrate, or forming an adhesive layer without conductive particles on the substrate and fixing conductive particles to the resulting adhesive layer.

[0025] The wiring board 20 has a circuit pattern for a first conductivity type and a circuit pattern for a second conductivity type on the substrate 21, and has a first electrode 22 and a second electrode 23 at positions corresponding to the first conductivity type electrode on the p side and the second conductivity type electrode on the n side, respectively, so that the light-emitting elements are arranged in units of subpixels that constitute one pixel. The wiring board 20 also forms circuit patterns such as data lines and address lines for matrix wiring, and makes it possible to turn on and off the light-emitting elements corresponding to each subpixel that constitutes one pixel. One pixel may be composed of, for example, three subpixels R (red), G (green), and B (blue), four subpixels RGBW (white) and RGBY (yellow), or two subpixels RG and GB. Furthermore, the wiring board 20 is preferably a light-transmitting substrate, the base material 21 is preferably glass, PET (Polyethylene Terephthalate), and the circuit pattern, first electrode 22, and second electrode 23 are preferably transparent conductive films such as ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), ZnO (Zinc-Oxide), or IGZO (Indium-Gallium-Zinc-Oxide).

[0026] Figure 2 is a schematic cross-sectional view showing the state in which individual pieces of the anisotropic conductive adhesive layer are transferred to predetermined positions on the wiring board and arranged by irradiating them with laser light from the substrate side. As shown in Figure 2, in the transfer process (A), laser light is irradiated from the substrate 11 side to transfer and arrange individual pieces 12a of the anisotropic conductive adhesive layer 12 to predetermined positions on the wiring board 21.

[0027] Here, in order to efficiently transfer individual pieces of the anisotropic conductive adhesive layer from the substrate, the anisotropic conductive adhesive layer provided on the substrate may be pre-treated to form the individual pieces in a matrix arrangement. One such pre-treatment method is to create a grid-like pattern of cuts in the anisotropic conductive adhesive layer, where multiple vertical and horizontal cuts intersect. These cuts may be made by mechanical or chemical means. Of course, the cuts may also be made by burning them off with laser light. By performing such treatment, multiple individual pieces of the anisotropic conductive adhesive layer can be arranged in a matrix on the substrate, making it easy to transfer the individual pieces with laser light. Note that these cuts do not necessarily need to be deep enough to expose the substrate; even cuts that do not expose the substrate will improve the transferability with laser light. Such pre-treatment may be performed after the anisotropic conductive adhesive layer is formed on the substrate, or before the anisotropic conductive adhesive layer is formed on the substrate, i.e., at the stage of the film-like anisotropic conductive adhesive layer.

[0028] In the transfer process (A), the individual pieces 12a of the anisotropic conductive adhesive layer 12 can be arranged in units of one pixel (for example, one pixel consisting of one RGB set), or they can be arranged in units of subpixels that make up one pixel (for example, any RGB). This makes it possible to accommodate light-emitting element arrays ranging from high PPI (Pixels Per Inch) to low PPI.

[0029] Furthermore, in the transfer process (A), it is preferable to arrange the individual pieces 12a of the anisotropic conductive adhesive layer 12 in units of one pixel or multiple pixels. For example, in the case of RGB, the light-emitting element is arranged in sets of 3 pixels, or in sets of 6 pixels including 3 redundant RGB circuits. Therefore, the anisotropic conductive film may be transferred to a set of 6 pixels, or it may be transferred in units of one pixel, or it may even be arranged in units of electrodes. On the other hand, in order to increase productivity, the anisotropic conductive film may be transferred in an area that does not impair transparency, for example, in an area of ​​1 mm × 1 mm.

[0030] Furthermore, when arranging individual pieces of the anisotropic conductive adhesive layer in units of one pixel, the film-like anisotropic conductive adhesive layer can be made into a tape, and its width can be set to one pixel, thereby limiting the aforementioned cuts to only one direction (the width direction of the tape). This tape width of one pixel does not mean a length equal to the size of one pixel, although this depends on the spacing between pixels, but rather a length that does not interfere with adjacent pixels.

[0031] Furthermore, the distance between individual pieces arranged at predetermined positions on the wiring board 20 is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the distance between individual pieces is preferably 3000 μm or less, more preferably 1000 μm or less, and even more preferably 500 μm or less. If the distance between individual pieces is too small, it is preferable to attach the anisotropic conductive film to the entire surface of the wiring board 20, and if the distance between individual pieces is too large, it is preferable to attach the anisotropic conductive film to predetermined positions on the wiring board 20. The distance between individual pieces can be measured using microscopic observation (optical microscope, metallurgical microscope, electron microscope, etc.).

[0032] For transferring individual pieces 12a of the anisotropic conductive adhesive layer 12, for example, a LIFT (Laser Induced Forward Transfer) apparatus can be used. The LIFT apparatus comprises, for example, a telescope that makes pulsed laser light emitted from a laser device into parallel light, a shaping optical system that uniformly shapes the spatial intensity distribution of the pulsed laser light that has passed through the telescope, a mask that allows the pulsed laser light shaped by the shaping optical system to pass through in a predetermined pattern, a field lens positioned between the shaping optical system and the mask, and a projection lens that reduces and projects the laser light that has passed through the pattern on the mask onto the donor substrate. The anisotropic conductive adhesive layer substrate 10, which is the donor substrate, is held on the donor stage, and the wiring substrate 21, which is the receptor substrate, is held on the receptor stage. The distance between the anisotropic conductive adhesive layer 12 and the wiring substrate 20 is preferably 10 to 1000 μm, more preferably 50 to 500 μm, and even more preferably 80 to 200 μm.

[0033] As the laser device, for example, an excimer laser that emits laser light with a wavelength of 180 nm to 360 nm can be used. The oscillation wavelengths of the excimer laser are, for example, 193, 248, 308, and 351 nm, and can be suitably selected from among these oscillation wavelengths depending on the light absorption properties of the material of the anisotropic conductive adhesive layer 12.

[0034] The mask uses a pattern in which a predetermined number of windows of a predetermined size are formed at a predetermined pitch so that the projection at the interface between the substrate 11 and the anisotropic conductive adhesive layer 12 results in a desired laser beam pattern. The mask is made by applying a pattern to the substrate 11, for example, by chrome plating, so that the window areas that are not chrome plated transmit the laser beam, while the chrome plated areas block the laser beam.

[0035] The light emitted from the laser device enters the telescopic optical system and propagates to the shaping optical system beyond it. The laser light is adjusted by the telescopic optical system so that it is approximately parallel at any position within the X-axis movement range of the donor stage just before it enters the shaping optical system. Therefore, it always enters the shaping optical system at approximately the same size and angle (perpendicular).

[0036] The laser light that has passed through the shaping optical system enters the mask via a field lens that, in combination with the projection lens, constitutes an image-side telecentric reduction projection optical system. The laser light that has passed through the mask pattern has its propagation direction changed vertically downward by the reflected light mirror and enters the projection lens. The laser light emitted from the projection lens enters from the substrate 11 side and is accurately projected onto a predetermined position on the anisotropic conductive adhesive layer 12 formed on its surface (bottom surface) at a reduced size of the mask pattern.

[0037] The pulse energy of the imaged laser light irradiated onto the interface between the anisotropic conductive adhesive layer and the substrate is preferably 0.001 to 2 J, more preferably 0.01 to 1.5 J, and even more preferably 0.1 to 1 J. The fluence is preferably 0.001 to 2 J / cm². 2 And more preferably 0.01 to 1 J / cm² 2 And more preferably 0.05 to 0.5 J / cm². 2 The pulse width (irradiation time) is preferably 0.01 to 1 × 10⁻¹⁰. 9 It is a picosecond, more preferably 0.1 to 1 × 10⁻⁶. 7 The duration is picosecond, and more preferably 1 to 1 × 10⁻⁶. 5 The pulse duration is picosecond. The pulse frequency is preferably 0.1 to 10,000 Hz, more preferably 1 to 1,000 Hz, and even more preferably 1 to 100 Hz. The number of irradiation pulses is preferably 1 to 30,000,000.

[0038] By using such a lift device, a shock wave is generated in the anisotropic conductive adhesive layer 12 irradiated with laser light at the interface between the base material 11 and the anisotropic conductive adhesive layer 12, and a plurality of pieces 12a are peeled off from the base material 11 and lifted toward the wiring board 20, and the plurality of pieces 12a can be landed at predetermined positions on the wiring board 20. Such a transfer method is called laser lift-off, and is, for example, a method using ablation by a laser. Thereby, the pieces 12a of the anisotropic conductive adhesive layer 12 can be transferred and arranged on the wiring board 20 with high precision and high efficiency, and the tact time can be shortened.

[0039] The reaction rate of the pieces 12a of the anisotropic conductive adhesive layer 12 after the transfer step (A) is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less. When the reaction rate of the pieces 12a is 25% or less, it becomes possible to thermocompression bond the light-emitting element in the mounting step (B). The reaction rate can be determined, for example, using FT-IR.

[0040] [Mounting Step (B)] FIG. 3 is a cross-sectional view schematically showing a state where a light-emitting element is mounted on pieces arranged at predetermined positions on a wiring board. As shown in FIG. 3, in the mounting step (B), the light-emitting element 30 is mounted on the pieces 12a arranged at predetermined positions on the wiring board 20.

[0041] The light-emitting element 30 includes a main body 31, a first conductivity type electrode 32, and a second conductivity type electrode 33, and has a horizontal structure in which the first conductivity type electrode 32 and the second conductivity type electrode 33 are arranged on the same surface side. The main body 31 includes, for example, a first conductivity type clad layer made of n-GaN, and, for example, In x Al y Ga 1-x-yThe device comprises an active layer made of an N layer and a second conductivity type cladding layer made of, for example, p-GaN, and has a so-called double heterostructure. The first conductivity type electrode 32 is formed in a part of the first conductivity type cladding layer by a passivation layer, and the second conductivity type electrode 33 is formed in a part of the second conductivity type cladding layer. When a voltage is applied between the first conductivity type electrode 32 and the second conductivity type electrode 33, carriers concentrate in the active layer and light emission occurs through recombination.

[0042] The method for mounting the light-emitting element 30 onto the wiring substrate 20 is not particularly limited, but examples include a method of directly transferring and positioning the light-emitting element 30 from the wafer substrate to the wiring substrate 20 using the laser lift-off method (LLO method), or a method of transferring and positioning the light-emitting element 30 from the transfer substrate to the wiring substrate 20 using a transfer substrate to which the light-emitting element 30 has been previously attached. As for the method of thermocompressing the light-emitting element 30 to the wiring substrate 20, a connection method used in known anisotropic conductive films can be appropriately selected and used. This makes it possible to anisotropically connect the light-emitting element 30 on the wiring substrate 20 with the wiring substrate 20 exposed and without an anisotropic conductive adhesive layer present between the light-emitting elements 30. Furthermore, by using a light-transmitting substrate for the wiring substrate 20, superior light transmittance can be obtained compared to the case where an anisotropic conductive film is attached to the entire surface of the wiring substrate 20.

[0043] As described above, according to the first embodiment of the method for manufacturing a display device, individual pieces 12a of the anisotropic conductive adhesive layer 12 can be transferred and arranged on the wiring substrate 20 with high precision and efficiency by irradiation with laser light, thereby shortening the cycle time. In the above embodiment, a method for manufacturing a display device as a display was given as an example, but this technology is not limited to this and can also be applied to a method for manufacturing a light-emitting device as a light source, for example.

[0044] [Modified version of the first embodiment] In the transfer step (A) of the first embodiment described above, as shown in Figure 2, the individual pieces 12a of the anisotropic conductive adhesive layer 12 were arranged on the wiring substrate 21 in units of multiple pixels, units of one pixel, or units of subpixels constituting one pixel. However, the method is not limited to these, and for example, they may be arranged in units of electrodes.

[0045] Figure 4 is a schematic cross-sectional view showing the state in which individual pieces of anisotropic conductive adhesive layer are transferred onto a wiring board at electrode positions by irradiating the substrate with laser light from the substrate side and then arranged. Figure 5 is a schematic cross-sectional view showing the state in which light-emitting elements are mounted on the individual pieces arranged on the wiring board in electrode units.

[0046] As shown in Figure 4, in the transfer step (A), the first individual piece 14 and the second individual piece 15 are transferred to the first electrode 22 and the second electrode 23, which correspond to, for example, the first conductivity type electrode 32 on the p side and the second conductivity type electrode 33 on the n side of the light-emitting element 30, respectively. Then, as shown in Figure 5, in the mounting step (B), the light-emitting element 30 may be mounted on the individual pieces arranged on the wiring board 20 in electrode units. This improves the transparency of the display device.

[0047] [Second Embodiment] The method for manufacturing a display device according to the second embodiment includes a transfer step in which an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light is placed opposite light-emitting elements arranged on a transfer substrate, and laser light is irradiated from the substrate side to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate; a re-transfer step in which the light-emitting elements onto which the individual pieces have been transferred are re-transferred onto a wiring substrate; and a mounting step in which the light-emitting elements arranged at predetermined positions on the wiring substrate are mounted via the individual pieces. Since individual pieces of the anisotropic conductive adhesive layer can be transferred and arranged with high precision and efficiency by irradiation with laser light, the cycle time can be shortened.

[0048] The following describes the transfer process (A1) in which individual pieces of the anisotropic conductive adhesive layer are transferred onto light-emitting elements arranged on a transfer substrate, the re-transfer process (A2) in which the light-emitting elements with the transferred pieces are re-transferred onto a wiring substrate, and the mounting process (BB) in which the light-emitting elements arranged at predetermined positions on the wiring substrate via the individual pieces. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0049] [Transfer process (A1)] Figure 6 is a schematic cross-sectional view showing the state in which an anisotropic conductive adhesive layer provided on the substrate and light-emitting elements arranged on the transfer substrate are facing each other, and Figure 7 is a schematic cross-sectional view showing the anisotropic conductive adhesive layer provided on the substrate. As shown in Figure 6, first, in the transfer process (A1), the anisotropic conductive adhesive layer substrate 10 and the transfer substrate 40 are facing each other.

[0050] The transfer substrate 40 comprises a base material 41 and light-emitting elements 30 arranged on the base material 41. The substrate 41 is appropriately selected according to the transfer method in the re-transfer step (A2) described later. For example, when using a transfer method utilizing laser ablation, the substrate 41 only needs to be transparent to laser light, and is preferably quartz glass having high light transmittance across all wavelengths. Also, for example, when the transfer substrate 40 is bonded to the wiring substrate 20 to transfer the light-emitting element 30, a silicone rubber layer may be provided.

[0051] In the transfer process (A1), a transfer method using laser ablation, such as laser lift-off, can be used, similar to the first embodiment described above. When using ablation, as shown in Figure 7, it is preferable that conductive particles are not present in the region X from 0 to 0.05 μm in the thickness direction from the side of the anisotropic conductive adhesive layer 12 on which the substrate 11 is provided.

[0052] In the anisotropic conductive adhesive layer 12, a region X extending 0 to 0.05 μm in the thickness direction from the side where the substrate 11 is provided is strongly affected by ablation. Therefore, it is preferable that conductive particles are not present in this region X. In other words, it is preferable that all conductive particles are present in the portion of the anisotropic conductive adhesive layer excluding region X without any overhang. Here, the state in which conductive particles are not present in a certain region means not only a state in which the entire conductive particle is not present in that region, but also a state in which even a part of the conductive particle is not included.

[0053] From the viewpoint of productivity of the anisotropic conductive adhesive layer, if conductive particles are mixed into region X, it is preferable that the number of conductive particles mixed into region X be 5% or less of the total number of conductive particles contained in the anisotropic conductive adhesive layer, and more preferably 1% or less.

[0054] Here, the thickness t of region X of the anisotropic conductive adhesive layer 12 may be 0 to 0.05 μm in the thickness direction from the side on which the substrate 11 is provided. In order to more reliably suppress the degradation of conductive particles due to ablation, it is preferable that this thickness t be 0 to 0.1 μm, more preferably 0 to 0.15 μm, and particularly preferably 0 to 0.2 μm, and that conductive particles are not present in this region. In other words, it is preferable that all conductive particles are present in the portion of the anisotropic conductive adhesive layer excluding these regions without any overflow. Similarly, from the viewpoint of productivity of the anisotropic conductive adhesive layer, if conductive particles are mixed into these regions, it is preferable that the number of conductive particles mixed into the region be 5% or less of the total number of conductive particles contained in the anisotropic conductive adhesive layer, and more preferably 1% or less.

[0055] Furthermore, in order to improve the ablation resistance of the conductive particles, it is preferable that the conductive particles be composed of metals that include a metal with a melting point of 1400°C or higher, as mentioned above. From the perspective of availability, it is preferable that the upper limit of the melting point be around 3500°C. From a similar viewpoint, it is preferable that the metals constituting the conductive particles include nickel, palladium, or ruthenium.

[0056] When using metal-coated resin particles, in which the surface of the resin particles is coated with metal, or metal-coated inorganic particles, in which the surface of the inorganic particles is coated with metal, it is preferable to make the thickness of the metal coating 0.08 μm or more, more preferably 0.1 μm or more, particularly preferably 0.15 μm or more, and most preferably 0.2 μm or more, in order to minimize the effect of ablation on the resin particles or inorganic particles. The upper limit of this coating thickness depends on the diameter of the conductive particles, but it is preferable to be about 20% of the diameter of the conductive particles or about 0.5 μm.

[0057] Such anisotropic conductive adhesive layers are applicable not only to the second embodiment but also to the first embodiment, its variations, and other forms.

[0058] Figure 8 is a schematic cross-sectional view showing the state in which individual pieces of the anisotropic conductive adhesive layer are transferred onto the light-emitting elements arranged on the transfer substrate by irradiating them with laser light from the substrate side. As shown in Figure 8, in the transfer process (A1), laser light is irradiated from the substrate 11 side to transfer and arrange individual pieces 16 of the anisotropic conductive adhesive layer 12 to predetermined positions on the wiring substrate 21. Laser light is irradiated from the substrate 11 side to transfer individual pieces 16 of the anisotropic conductive adhesive layer 12 onto the light-emitting elements 30 arranged on the transfer substrate.

[0059] Similar to the first embodiment described above, a lifting device can be used, for example, to transfer the individual pieces 16 of the anisotropic conductive adhesive layer 12. By using a lifting device, a shock wave is generated in the anisotropic conductive adhesive layer 12 irradiated with laser light at the interface between the substrate 11 and the anisotropic conductive adhesive layer 12, peeling off the multiple individual pieces 16 from the substrate 11 and lifting them toward the light-emitting elements 30 arranged on the transfer substrate, allowing the individual pieces 16 to land on the light-emitting elements 30 with high precision, thereby shortening the cycle time.

[0060] [Retransfer process (A2)] Figure 9 is a schematic cross-sectional view showing the state in which a light-emitting element with individual pieces transferred onto it is re-transferred onto a wiring board. As shown in Figure 9, in the re-transfer step (A2), the light-emitting element 30 with individual pieces 16 transferred onto it is re-transferred onto the wiring board. The method of re-transfer is not particularly limited, but examples include a method in which the light-emitting element 30 with individual pieces 16 transferred onto it is directly transferred and placed from the transfer substrate 40 to the wiring board 20 using the laser lift-off method (LLO method), and a method in which the light-emitting element 30 with individual pieces 16 transferred onto it is transferred and placed from the transfer substrate 40 to the wiring board 20 using a transfer substrate to which the light-emitting element 30 has been previously attached.

[0061] Furthermore, in the retransfer step (A2), it is preferable to transfer the light-emitting element 30 in units of subpixels that constitute one pixel. This makes it possible to accommodate light-emitting element arrays ranging from those with high PPI (Pixels Per Inch) to those with low PPI.

[0062] [Implementation Process (BB)] In the mounting process (BB), the light-emitting elements 30 arranged at predetermined positions on the wiring board 20 are mounted via individual pieces 16. The mounted state of the light-emitting elements 30 is the same as in Figure 3. As a method for mounting the light-emitting elements 30 to the wiring board 20, a connection method such as thermocompression bonding, which is used in known anisotropic conductive films, can be appropriately selected and used. This allows the light-emitting elements 30 to be anisotropically connected on the wiring board 20 with the wiring board 20 exposed and no anisotropic conductive adhesive layer present between the light-emitting elements 30. Furthermore, by using a light-transmitting substrate for the wiring board 20, superior light transmittance can be obtained compared to when an anisotropic conductive film is attached to the entire surface of the wiring board 20.

[0063] As described above, according to the manufacturing method of the display device according to the second embodiment, individual pieces 16 of the anisotropic conductive adhesive layer 12 can be transferred and arranged on the light-emitting element 30 with high precision and efficiency by irradiation with laser light, thereby shortening the cycle time.

[0064] [Modified version of the second embodiment] In the transfer step (A1) of the second embodiment described above, as shown in Figure 8, individual pieces 16 of the anisotropic conductive adhesive layer 12 are transferred onto the light-emitting element 30. However, the invention is not limited to this, and for example, individual pieces of the anisotropic conductive adhesive layer may be transferred onto the light-emitting element in electrode units. That is, the first individual pieces and the second individual pieces may be transferred to, for example, the first conductivity type electrode 32 on the p side and the second conductivity type electrode 33 on the n side of the light-emitting element 30, respectively. This makes it possible to improve the transparency of the display device. [Examples]

[0065] <2. Examples> In this embodiment, an anisotropic conductive adhesive layer provided on quartz glass and a base glass were placed facing each other, and laser light was irradiated from the substrate side to transfer individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the base glass and arrange them. The individual pieces arranged on the base glass were then evaluated visually using a metallurgical microscope. However, this embodiment is not limited to these.

[0066] [Fabrication of anisotropic conductive adhesive layer] An anisotropic conductive adhesive layer substrate was prepared by laminating an anisotropic conductive adhesive layer, in which conductive particles with an average particle size of 2.2 μm were aligned, onto quartz glass, thereby providing a 4 μm thick anisotropic conductive adhesive layer on the quartz glass. The binder for the anisotropic conductive adhesive layer was prepared by blending 42 parts by mass of phenoxy resin (product name: PKHH, manufactured by Tomoe Chemical Industry Co., Ltd.), 40 parts by mass of high-purity bisphenol A type epoxy resin (product name: YL-980, manufactured by Mitsubishi Chemical Corporation), 10 parts by mass of hydrophobic silica (product name: R202, manufactured by Nippon Aerosil Co., Ltd.), 3 parts by mass of acrylic rubber (product name: SG80H, manufactured by Nagase ChemteX Corporation), and 5 parts by mass of cationic polymerization initiator (product name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.), and coating and drying the mixture onto a 50 μm thick PET film to prepare the resin layer. Conductive particles (average particle size 2.2 μm, resin core metal coated fine particles, Ni plating 0.2 μm thick, manufactured by Sekisui Chemical Co., Ltd.) were aligned from the obtained resin layer using the method described in Japanese Patent No. 6187665, such that the conductive particles substantially coincided with one interface of the resin layer. In a plan view of the anisotropic conductive adhesive layer, the conductive particles were aligned in a hexagonal lattice arrangement such that the distance between conductive particles was twice the particle diameter.

[0067] [Transfer of anisotropic conductive adhesive layer] A lift device (MT-30C200) was used to transfer individual pieces of the anisotropic conductive adhesive layer onto a raw glass substrate. As described above, the lift device comprises a telescope that makes the pulsed laser light emitted from the laser device into parallel light, a shaping optical system that uniformly shapes the spatial intensity distribution of the pulsed laser light that has passed through the telescope, a mask that allows the pulsed laser light shaped by the shaping optical system to pass through in a predetermined pattern, a field lens positioned between the shaping optical system and the mask, and a projection lens that reduces and projects the laser light that has passed through the pattern on the mask onto the donor substrate. The anisotropic conductive adhesive layer substrate, which is the donor substrate, was held on the donor stage, and the raw glass substrate, which is the receptor substrate, was held on the receptor stage, with the distance between the anisotropic conductive adhesive layer and the raw glass being 100 μm.

[0068] The laser device used was an excimer laser with an oscillation wavelength of 248 nm. The pulse energy of the laser light was 600 J, and the fluence was 150 J / cm². 2 The pulse width (irradiation time) was 30,000 picoseconds, the pulse frequency was 0.01 kHz, and the number of irradiation pulses was 1 pulse per ACF1 piece. The pulse energy of the imaged laser light irradiated at the interface between the anisotropic conductive adhesive layer and the substrate was 0.001 to 2 J, and the fluence was 0.001 to 2 J / cm². 2 The pulse width (irradiation time) is 0.01 to 1 × 10⁻⁶. 9 The pulse duration was picosecond, the pulse frequency ranged from 0.1 to 10,000 Hz, and the number of pulses ranged from 1 to 30,000,000.

[0069] The mask used a pattern in which windows of a predetermined size were formed at a predetermined pitch so that the projection at the interface between the anisotropic conductive adhesive layer of the anisotropic conductive adhesive layer substrate (the donor substrate) and the quartz glass would be an array of laser beams measuring 30 μm vertically and 40 μm horizontally, with a vertical pitch of 120 μm and a horizontal pitch of 160 μm.

[0070] [Evaluation of transcription] The reaction rate of individual pieces of anisotropic conductive adhesive layer arranged on a glass surface was measured to be 17.4%. The reaction rate was determined by the rate of decrease of epoxy groups in the individual pieces of anisotropic conductive adhesive layer using FT-IR. Specifically, the amount by which the epoxy groups in the individual pieces decreased due to laser light transfer was measured using the 914 cm⁻¹ infrared absorption spectrum. -1 This was determined by measuring the absorption of the substance.

[0071] Figure 10 is a metallurgical microscope image showing individual pieces of anisotropic conductive adhesive layer arranged on a bare glass surface, and Figure 11 is a magnified image of the metallurgical microscope image shown in Figure 10. As shown in Figures 10 and 11, it was confirmed that the individual pieces of anisotropic conductive adhesive layer were transferred onto the bare glass surface according to the pattern of the mask. In other words, it was found that individual pieces of anisotropic conductive adhesive layer can be transferred and arranged with high precision and efficiency by irradiation with laser light, thereby shortening the cycle time.

[0072] While embodiments of the present invention have been described in detail above, the present invention can also be expressed from a different perspective as follows: (1) to (29) and (U1) to (U18). (1) A transfer step in which an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light is placed opposite a wiring substrate, and laser light is irradiated from the substrate side to transfer and arrange individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate, A mounting step of mounting light-emitting elements on individual pieces arranged at predetermined positions on the aforementioned wiring board. A method for manufacturing a display device having [a certain feature]. (2) The method for manufacturing a display device according to (1), wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of one pixel. (3) The method for manufacturing a display device according to (1), wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of subpixels constituting one pixel. (4) The method for manufacturing a display device according to (1), wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of multiple pixels. (5) The method for manufacturing a display device according to (1), wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of electrodes of the light-emitting element. (6) The method for manufacturing a display device according to any one of (1) to (5), wherein the distance between individual pieces arranged at predetermined positions on the wiring board is 3 μm or more. (7) A method for manufacturing a display device according to any one of (1) to (6), wherein the reaction rate of the individual pieces after the transfer step is 25% or less. (8) The wavelength of the laser light is 180 nm to 360 nm, A method for manufacturing a display device according to any one of (1) to (7), wherein the anisotropic conductive adhesive layer comprises a resin having a maximum absorption wavelength in the range of 180 nm to 360 nm. (9) The method for manufacturing a display device according to any one of (1) to (8), wherein the anisotropic conductive adhesive layer contains conductive particles. (10) A method for manufacturing a display device according to any one of (1) to (9), wherein the anisotropic conductive adhesive layer is configured by aligning the conductive particles in the planar direction. (11) The method for manufacturing a display device according to (9) or (10), wherein the conductive particles are not present in a region of the anisotropic conductive adhesive layer extending 0 to 0.05 μm in the thickness direction from the side on which the substrate is provided. (12) The conductive particles are metal-coated resin particles in which the surface of resin particles is coated with metal, or metal-coated inorganic particles in which the surface of inorganic resin particles is coated with metal. The method for manufacturing a display device according to any one of (9) to (11), wherein the thickness of the metal coating is 0.15 μm or more. (13) The method for manufacturing a display device according to any one of (9) to (12), wherein the metal constituting the conductive particles is a metal having a melting point of 1400°C or higher. (14) A transfer step in which an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light and light-emitting elements arranged on a transfer substrate are placed facing each other, and laser light is irradiated from the substrate side to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate, A retransfer step involves retransferring the light-emitting element onto the wiring substrate, A mounting step of mounting light-emitting elements arranged at predetermined positions on the wiring board via the aforementioned pieces. A method for manufacturing a display device having [a certain feature]. (15) The method for manufacturing a display device according to (14), wherein in the transfer step, individual pieces of the anisotropic conductive adhesive layer are transferred onto the light-emitting element in electrode units. (16) The method for manufacturing a display device according to (14) or (15), wherein in the retransfer step, the light-emitting element is transferred in units of subpixels constituting one pixel. (17) A method for manufacturing a wiring board with an anisotropic conductive adhesive layer, comprising the steps of facing an anisotropic conductive adhesive layer provided on a substrate and a wiring board, and irradiating the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring board. (18) A method for manufacturing an anisotropic conductive adhesive layer-equipped light-emitting element, comprising a transfer step of facing an anisotropic conductive adhesive layer provided on a substrate and light-emitting elements arranged on a transfer substrate, and irradiating the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate. (19) A film-like anisotropic conductive adhesive layer used for transfer by laser lift-off. (20) The film-like anisotropic conductive adhesive layer according to (19) containing conductive particles. (21) The film-like anisotropic conductive adhesive layer according to (20), wherein the conductive particles are not present in a region of 0 to 0.05 μm in the thickness direction from the substrate-side surface provided during transfer by laser lift-off. (22) The conductive particles are metal-coated resin particles in which the surface of resin particles is coated with metal, or metal-coated inorganic particles in which the surface of inorganic resin particles is coated with metal. The film-like anisotropic conductive adhesive layer according to (20) or (21), wherein the thickness of the metal coating is 0.15 μm or more. (23) The film-like anisotropic conductive adhesive layer according to any one of (20) to (22), wherein the metal constituting the conductive particles is a metal having a melting point of 1400°C or higher. (24) The film-like anisotropic conductive adhesive layer according to any one of (20) to (23), wherein the metal constituting the conductive particles is nickel, palladium, or ruthenium. (25) A substrate on which an anisotropic conductive adhesive layer is laminated for use in laser lift-off transfer. (26) Application of anisotropic conductive adhesive layers to anisotropic conductive adhesive layers for laser lift-off transfer. (27) Applications of anisotropic conductive adhesive layers for the manufacture of anisotropic conductive adhesive layers for laser lift-off transfer. (28) Applications for the manufacture of substrates on which anisotropic conductive adhesive layers are laminated, for use in the transfer of anisotropic conductive adhesive layers by laser lift-off. (29) Application of anisotropic conductive adhesive layers to laser lift-off. (U1) A transfer mechanism that places an anisotropic conductive adhesive layer provided on a substrate that is transparent to laser light and a wiring substrate opposite each other, and irradiates the substrate with laser light to transfer and arrange individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate, A mounting mechanism for mounting light-emitting elements on individual pieces arranged at predetermined positions on the aforementioned wiring board, A manufacturing system for a display device having the following features. (U2) The manufacturing system for a display device according to (U1), wherein the transfer mechanism arranges the individual pieces of the anisotropic conductive adhesive layer in units of one pixel. (U3) The manufacturing system for a display device according to (U1), wherein the transfer mechanism arranges the individual pieces of the anisotropic conductive adhesive layer in units of subpixels constituting one pixel. (U4) The manufacturing system for a display device according to (U1), wherein the transfer mechanism arranges the individual pieces of the anisotropic conductive adhesive layer in units of multiple pixels. (U5) The manufacturing system for a display device according to (U1), wherein the transfer mechanism arranges the individual pieces of the anisotropic conductive adhesive layer in units of electrodes of the light-emitting element. (U6) A manufacturing system for a display device according to any one of (U1) to (U5), wherein the distance between individual pieces arranged at predetermined positions on the wiring board is 3 μm or more. (U7) A manufacturing system for a display device according to any one of (U1) to (U6), wherein the reaction rate of the individual pieces after transfer by the transfer mechanism is 25% or less. (U8) The wavelength of the laser light is 180 nm to 360 nm. A manufacturing system for a display device according to any one of (U1) to (U7), wherein the anisotropic conductive adhesive layer contains a resin having a maximum absorption wavelength in the range of 180 nm to 360 nm. (U9) The manufacturing system for a display device according to any one of (U1) to (U8), wherein the anisotropic conductive adhesive layer contains conductive particles. (U10) A manufacturing system for a display device according to (U9), wherein the anisotropic conductive adhesive layer is configured by aligning the conductive particles in the planar direction. (U11) A manufacturing system for a display device according to (U9) or (U10), wherein the conductive particles are not present in a region of 0 to 0.05 μm in the thickness direction from the side of the anisotropic conductive adhesive layer on which the substrate is provided. (U12) The conductive particles are metal-coated resin particles in which the surface of resin particles is coated with metal, or metal-coated inorganic particles in which the surface of inorganic particles is coated with metal. A manufacturing system for a display device according to any one of (U9) to (U11), wherein the thickness of the metal coating is 0.15 μm or more. (U13) A manufacturing system for a display device according to any one of (U9) to (U12), wherein the metal constituting the conductive particles is a metal having a melting point of 1400°C or higher. (U14) A transfer mechanism that places an anisotropic conductive adhesive layer on a substrate that is transparent to laser light and light-emitting elements arranged on a transfer substrate opposite each other, and irradiates the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate, A retransfer mechanism for retransferring the light-emitting element onto the wiring substrate, A mounting mechanism for mounting light-emitting elements arranged at predetermined positions on the wiring board via the aforementioned pieces, A manufacturing system for a display device having the following features. (U15) The manufacturing system for a display device according to the description, wherein the transfer mechanism transfers individual pieces of the anisotropic conductive adhesive layer onto the light-emitting element in electrode units (U14). (U16) A manufacturing system for a display device according to (U14) or (U15), wherein the retransfer mechanism transfers the light-emitting element in units of subpixels constituting one pixel. (U17) A manufacturing system for a wiring board with an anisotropic conductive adhesive layer, comprising a mechanism for transferring individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring board by irradiating a wiring board with an anisotropic conductive adhesive layer provided on a substrate, and irradiating the substrate with laser light. (U18) A manufacturing system for light-emitting elements with an anisotropic conductive adhesive layer, comprising a transfer mechanism that places an anisotropic conductive adhesive layer provided on a substrate and light-emitting elements arranged on a transfer substrate opposite each other, and irradiates the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate.

[0073] Each of the constituent elements in the many embodiments described above can be subdivided, and these subdivided constituent elements can be introduced into (1) to (29) and (U1) to (U18) individually or in combination. [Explanation of Symbols]

[0074] 10 Substrate, 11 Base material, 12 Anisotropic conductive adhesive layer, 12a Piece, 13 Conductive particles, 20 Wiring board, 21 Base material, 22 First electrode, 23 Second electrode, 30 Light-emitting element, 31, 32 First conductive electrode, 33 Second conductive electrode, 40 Transfer substrate, 41 Base material

Claims

1. A transfer step involves placing an anisotropic conductive adhesive layer, provided on a substrate that is transparent to laser light, opposite a wiring substrate, and irradiating the substrate with laser light to transfer and arrange individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate. A mounting step of mounting light-emitting elements on individual pieces arranged at predetermined positions on the aforementioned wiring board. A method for manufacturing a display device having [a certain feature].

2. The method for manufacturing a display device according to claim 1, wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of one pixel.

3. The method for manufacturing a display device according to claim 1, wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of subpixels constituting one pixel.

4. The method for manufacturing a display device according to claim 1, wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of multiple pixels.

5. The method for manufacturing a display device according to claim 1, wherein in the transfer step, the individual pieces of the anisotropic conductive adhesive layer are arranged in units of electrodes of the light-emitting element.

6. The method for manufacturing a display device according to any one of claims 1 to 5, wherein the distance between individual pieces arranged at predetermined positions on the wiring board is 3 μm or more.

7. A method for manufacturing a display device according to any one of claims 1 to 6, wherein the reaction rate of the individual pieces after the transfer step is 25% or less.

8. The wavelength of the laser light is 180 nm to 360 nm. The method for manufacturing a display device according to any one of claims 1 to 7, wherein the anisotropic conductive adhesive layer comprises a resin having a maximum absorption wavelength in the range of 180 nm to 360 nm.

9. The method for manufacturing a display device according to any one of claims 1 to 8, wherein the anisotropic conductive adhesive layer contains conductive particles.

10. The method for manufacturing a display device according to claim 9, wherein the anisotropic conductive adhesive layer is configured by aligning the conductive particles in the planar direction.

11. The method for manufacturing a display device according to claim 9 or 10, wherein the conductive particles are not present in a region of 0 to 0.05 μm in the thickness direction from the side of the anisotropic conductive adhesive layer on which the substrate is provided.

12. The conductive particles are metal-coated resin particles, in which the surface of resin particles is coated with metal, or metal-coated inorganic particles, in which the surface of inorganic particles is coated with metal. The method for manufacturing a display device according to any one of claims 9 to 11, wherein the thickness of the metal coating is 0.15 μm or more.

13. A method for manufacturing a display device according to any one of claims 9 to 12, wherein the metal constituting the conductive particles includes a metal having a melting point of 1400°C or higher.

14. A transfer step involves placing an anisotropic conductive adhesive layer on a substrate that is transparent to laser light and light-emitting elements arranged on a transfer substrate facing each other, and irradiating the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate, A retransfer step involves retransferring the light-emitting element onto the wiring substrate, A mounting step of mounting light-emitting elements arranged at predetermined positions on the wiring board via the aforementioned pieces. A method for manufacturing a display device having [a certain feature].

15. The method for manufacturing a display device according to claim 14, wherein in the transfer step, individual pieces of the anisotropic conductive adhesive layer are transferred onto the light-emitting element in electrode units.

16. The method for manufacturing a display device according to claim 14 or 15, wherein the retransfer step involves transferring the light-emitting element in units of subpixels constituting one pixel.

17. A method for manufacturing a wiring substrate with an anisotropic conductive adhesive layer, comprising the steps of facing an anisotropic conductive adhesive layer provided on a substrate and a wiring substrate, and irradiating the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer to predetermined positions on the wiring substrate.

18. A method for manufacturing an anisotropic conductive adhesive layer-equipped light-emitting element, comprising a transfer step of facing an anisotropic conductive adhesive layer provided on a substrate and light-emitting elements arranged on a transfer substrate, and irradiating the substrate with laser light to transfer individual pieces of the anisotropic conductive adhesive layer onto the light-emitting elements arranged on the transfer substrate.

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