Method for producing bonded light-emitting element wafer and method for transferring micro-led

Abstract

The present invention provides a method for producing a bonded light-emitting element wafer wherein a light-emitting element structure that serves as a micro-LED and a substrate to be bonded are bonded to each other by the intermediary of an adhesive, the method comprising: a step in which a light-emitting element structure and a substrate to be bonded are bonded to each other by the intermediary of an adhesive, thereby obtaining a bonded wafer; a step in which the bonded wafer is optically examined for defective parts so as to form map data for removal; and a step in which a defective part of the bonded wafer is irradiated with a laser light beam for removal from the substrate to be bonded side on the basis of the map data for removal so that the adhesive contained in the defective part is sublimated by absorbing the laser light beam for removal, thereby removing a part of the light-emitting element structure contained in the defective part so as to obtain a bonded light-emitting element wafer. Consequently, the present invention provides a method for producing a bonded light-emitting element wafer, the method being capable of producing a bonded light-emitting element wafer by selectively removing a defective part of a light-emitting element structure.

Description

Method for manufacturing a junction-type light-emitting element wafer and method for transferring micro LEDs

[0001] The present invention relates to a method for manufacturing a junction-type light-emitting element wafer and a method for transferring micro LEDs.

[0002] A technology for bonding wafers via BCB has been disclosed as a wafer for AlGaInP-based micro LEDs (μ-LEDs).

[0003] In the above-mentioned wafers, since the wafers are bonded together, bonding defects may occur due to the surface conditions of the bonded wafer and the wafer to be bonded, or due to the presence of foreign matter in the epitaxial layer or at the bonding interface.

[0004] In many cases, the defective bonding portion has a convex shape, which causes a decrease in the accuracy of shape and dimensions during the device structure fabrication process, particularly during processing by photolithography.

[0005] Furthermore, when μ-LED dies fabricated from a wafer having such convex defects are transferred to a transfer substrate, the convex defects cause non-uniformity in the applied pressure, resulting in transfer failure.

[0006] Therefore, when transferring elements from a wafer on which junction-type μ-LEDs are formed, it is necessary to remove the convex defective portions before transferring the elements.

[0007] With conventional LED dice, which are designed as discrete devices, there are various methods for physically removing defective parts.

[0008] For example, Patent Document 1 discloses a technology for holding dies by suction. However, when using a single plate for suction and holding, it is assumed that the heights of all dies are within a certain tolerance range. If a protrusion occurs on a wafer before device fabrication due to a bonding defect, the heights of the dies after device fabrication will be uneven. Therefore, the prior art exemplified here will cause defects during transfer. Furthermore, because the transfer is performed in bulk, it is not a technology that can selectively remove defective parts.

[0009] Patent Document 2 discloses a technique for picking up dies using an electrostatic method, but like Patent Document 1, it is based on the premise that the dies are picked up onto a single plate-shaped jig, and is therefore a method that cannot be applied when convex portions are generated.

[0010] Patent Document 3 discloses a technique for optically detecting defects and mechanically extracting defective dies. Mechanical extraction of defective dies requires a certain size (150 μm square or larger), and this technique cannot be applied to μ-LED dies, which are smaller than 100 μm square.

[0011] Furthermore, even if it were possible to pick up a defective die by improving the technology of Patent Document 3, the defective part is firmly bonded to the bonded wafer by the BCB, and it is impossible to mechanically pick up the defective die while holding the BCB part.

[0012] Thus, Patent Documents 1 to 3 do not disclose a technique for selectively removing defective portions of the μ-LED epitaxial layer portion firmly bonded to the bonded wafer via BCB or of the μ-LED die after device fabrication.

[0013] Patent Documents 4 and 5 disclose techniques for detecting defects in organic EL devices, mainly those caused by foreign matter, and removing them by laser irradiation.

[0014] Patent Document 6 discloses a defective LED removal device that detects and removes defective LED chips, in which LEDs with poor brightness are removed using a suction nozzle.

[0015] Patent Document 7 discloses a method for evaluating LEDs for defects that cause optical and electrical malfunctions, and removing the defective LEDs while leaving good LEDs. The process for removing the defective LEDs in Patent Document 7 involves using a laser to raise the temperature of the LED above its evaporation temperature to evaporate the defective LED structure, or applying a laser beam along the cut of the defective LED to cut the metal substrate.

[0016] Japanese Patent Application Laid-Open No. 2021-019162 Japanese Patent Application Laid-Open No. 2018-163900 Japanese Patent Application Laid-Open No. 2009-21572 Japanese Patent Application Laid-Open No. 2004-119243 International Publication No. WO2010 / 092749 Japanese Patent Application Laid-Open No. 2020-129658 Special Publication No. 2008-527719

[0017] In many cases, when the starting substrate is removed, defective bonding areas manifest as convex defects on the epitaxial layer on the side from which the starting substrate was removed. In particular, the size of convex defects caused by poor curing of BCB can reach a height of approximately 100 to 300 μm and a diameter of approximately 500 to 5,000 μm, adversely affecting photolithography. When photolithography is performed using contact exposure, the wafer and photomask are in close contact under vacuum, so the mask deforms to match the wafer's total thickness variation (TTV: the difference between the maximum and minimum thickness values). The presence of convex defective bonding areas causes the incident light from the exposure source to be obliquely incident, resulting in deviations from the mask pattern, distortion, and enlargement of the formed pattern. This causes the shapes of elements, electrodes, protective films, etc. to deviate from the design values, resulting in size and positional deviations. When such elements are transferred to the mounting board, misalignment occurs with the pattern on the mounting board, reducing mounting accuracy and increasing the defect rate. Deviations from the design value are difficult to detect using only photoluminescence (PL) characteristic inspections or visual inspections, and an abnormality may only be noticed after mounting and turning on the power. If a defect is discovered after mounting, remounting is required, which increases mounting costs.

[0018] Furthermore, when μ-LED dies fabricated from such a wafer are transferred to a transfer substrate, the protrusions tend to cause non-uniformity in the applied pressure, which can easily lead to transfer failures.

[0019] Furthermore, the adhesive layer functions as an adhesive even in the defective portion, and the defective portion will not peel off or separate even with a tensile strength equivalent to vacuum suction or adhesion, and the defective portion will remain in place.

[0020] Defective parts are not limited to defective connections, but also include defective element characteristics. Similar to defective connections, defective element characteristics are difficult to detect through PL characteristic inspections or visual inspections alone, and the abnormality may only be noticed after the device is mounted and powered on.

[0021] The present invention has been made to solve the above-mentioned problems, and aims to provide a method for manufacturing a bonded light-emitting element wafer that can selectively remove defective parts of a light-emitting element structure that becomes a micro-LED bonded to a bonded wafer via an adhesive, thereby manufacturing a bonded light-emitting element wafer, and a method for transferring micro-LEDs that can prevent defective micro-LEDs from being transferred.

[0022] In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a bonded light-emitting element wafer in which light-emitting element structures that will become micro LEDs and a bonded substrate that is transparent to removal laser light are bonded via an adhesive that absorbs the removal laser light, the method comprising: a step of bonding the light-emitting element structures and the bonded substrate via the adhesive to obtain a bonded wafer; a step of optically inspecting defective portions of the bonded wafer and creating removal map data; and a step of irradiating the defective portions of the bonded wafer from the bonded substrate side based on the removal map data, causing the removal laser light to be absorbed by portions of the adhesive that are included in the defective portions, and sublimating the portions of the adhesive that are included in the defective portions, thereby removing the portions of the light-emitting element structures that are included in the defective portions, and obtaining the bonded light-emitting element wafer.

[0023] With this method for manufacturing a bonded light-emitting element wafer of the present invention, defective portions of the bonded wafer can be optically inspected to create removal map data, and defective portions (e.g., defective bonding portions and portions with defective element characteristics) of the light-emitting element structures included in the bonded light-emitting element wafer can be selectively removed by irradiating laser light based on the created removal map data. Furthermore, with the method for manufacturing a bonded light-emitting element wafer of the present invention, defective portions of the light-emitting element structures can be selectively removed easily without using mechanical techniques. In other words, with the method for manufacturing a bonded light-emitting element wafer of the present invention, a bonded light-emitting element wafer from which defective portions of the light-emitting element structures have been removed can be easily manufactured.

[0024] The step of creating the removal map data preferably includes the steps of: acquiring a photoluminescence spectrum of the bonded wafer, and creating first map data regarding the defective portion based on a peak wavelength, a peak intensity, and / or a peak half-width as a criterion; and photographing the bonded wafer from the bonded substrate side with a CCD camera, and creating second map data regarding the defective portion based on the color tone of the image obtained by photographing. The removal map data is preferably created using the first map data and the second map data.

[0025] Based on the removal map data created in this manner, it is possible to selectively and reliably remove all of the defective bonding portions and defective element characteristic portions of the light-emitting element structures included in the bonded light-emitting element wafer.

[0026] In this case, for example, the light emitting element structures are subjected to element separation processing, and the removal map data can be created for the bonded wafer including the light emitting element structures that have been subjected to element separation processing.

[0027] The first map data and the second map data may be created for a bonded wafer including light-emitting element structures separated into elements, and the created map data for removal may be synthesized. In this way, defective portions of the light-emitting element structures can be selectively removed easily without affecting the good portions of the light-emitting element structures.

[0028] Alternatively, the step of creating the removal map data may further include the steps of: irradiating a topology detection laser beam onto the surface of the light-emitting element structure of the bonded wafer from an oblique direction to obtain topology data; and creating topology map data relating to the defective portion based on the topology data; creating removal map data relating to the defective portion using the first map data, the second map data, and the topology map data; and removing the portion of the light-emitting element structure that is included in the defective portion, and then performing element separation processing on the light-emitting element structure.

[0029] In the case where removal map data is created before performing element isolation processing, the topology map data is acquired, and this is combined with the first map data and the second map data to create removal map data, and removal is performed using a laser based on this removal map data, thereby making it possible to selectively and reliably remove all of the defective bonding portions and defective element characteristic portions of the light-emitting element structures included in the bonded light-emitting element wafer. Furthermore, by doing so, it is possible to reduce portions with poor photolithography accuracy around the defective portions of the light-emitting element structures.

[0030] For example, the removal laser light may be a laser light having a wavelength of 170 nm or more and 360 nm or less.

[0031] The removal laser light is not particularly limited as long as it can pass through the substrates to be joined and is absorbed by the adhesive, but laser light with a wavelength of 170 nm or more and 360 nm or less can be used.

[0032] For example, the adhesive may be one having a light absorption edge in the wavelength range of 170 nm or more and 360 nm or less.

[0033] Such adhesives can be easily evaporated using removal laser light with a wavelength of 170 nm or more and 360 nm or less.

[0034] In this case, for example, the adhesive may be selected from the group consisting of benzocyclobutene, silicone resin, epoxy resin, SOG, polyimide, and amorphous fluorine-based resin.

[0035] There are no particular limitations on the adhesive as long as it absorbs the removal laser light, but by using such adhesives, for example, the light emitting element structure can be firmly bonded to the substrate to be bonded.

[0036] It is preferable that a protective material be applied to the light emitting device structure before removing the portion of the light emitting device structure that is included in the defective portion.

[0037] Such a protective material can prevent good portions of the light emitting element structure that should not be removed from being damaged by a receiving jig or the like when the bonded wafer is irradiated with laser light.

[0038] As the protective material, it is preferable to use a polyvinyl acetate-containing protective material or a polyvinyl alcohol-containing protective material.

[0039] Such a protective material is preferable because it can be easily removed.

[0040] The present invention also provides a method for transferring micro-LEDs, which transfers the micro-LEDs from a bonded light-emitting element wafer including the micro-LEDs to a transfer substrate, comprising: manufacturing a bonded light-emitting element wafer including the light-emitting element structures that have been subjected to the element separation process by the method for manufacturing a bonded light-emitting element wafer of the present invention; and transferring the light-emitting element structures as the micro-LEDs from the bonded light-emitting element wafer to the transfer substrate.

[0041] As described above, the method for manufacturing a bonded light-emitting element wafer of the present invention can selectively remove defective portions (e.g., defective bonding portions and portions with defective element characteristics) of the light-emitting element structures included in the bonded light-emitting element wafer, thereby manufacturing a bonded light-emitting element wafer from which the defective portions of the light-emitting element structures have been removed. Therefore, the method for transferring micro LEDs of the present invention can prevent the transfer of defective light-emitting element structures, i.e., defective micro LEDs.

[0042] As described above, the method for manufacturing a bonded light-emitting element wafer of the present invention makes it possible to selectively remove defective portions of light-emitting element structures included in the bonded light-emitting element wafer. That is, the method for manufacturing a bonded light-emitting element wafer of the present invention makes it possible to manufacture a bonded light-emitting element wafer that does not include defective light-emitting element structures.

[0043] Furthermore, the method for transferring micro-LEDs of the present invention can prevent defective micro-LEDs from being transferred.

[0044] FIG. 1 is a schematic flowchart of a method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 2 is a schematic cross-sectional view showing a part of a step of obtaining a bonded wafer in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 3 is a schematic cross-sectional view showing another part of the step of obtaining a bonded wafer in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 4 is a schematic cross-sectional view of a bonded wafer obtained in the step of obtaining a bonded wafer in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 5 is a schematic plan view of a bonded wafer obtained in the step of obtaining a bonded wafer in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 6 is a schematic cross-sectional view showing a part of a step of obtaining a bonded light-emitting element wafer in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 7 is a schematic plan view of a bonded wafer receiving jig used in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 8 is a schematic cross-sectional view showing another part of the step of obtaining a bonded light-emitting element wafer in a first embodiment of the method for manufacturing a bonded light-emitting element wafer according to the present invention. FIG. 1 is a schematic plan view of a light-emitting element structure after removing a portion included in a defective part of the light-emitting element structure in a first embodiment of the method for manufacturing a bonded light-emitting element wafer of the present invention. FIG. 2 is a schematic cross-sectional view of a bonded light-emitting element wafer obtained after removing a portion included in a defective part of the light-emitting element structure in a first embodiment of the method for manufacturing a bonded light-emitting element wafer of the present invention. FIG. 3 is a schematic cross-sectional view of a bonded light-emitting element wafer after element separation processing in a first embodiment of the method for manufacturing a bonded light-emitting element wafer of the present invention. FIG. 4 is a schematic cross-sectional view of a bonded light-emitting element wafer obtained in a first embodiment of the method for manufacturing a bonded light-emitting element wafer of the present invention.

[0045] As described above, there was a need to develop a method for manufacturing a bonded light-emitting element wafer that can selectively remove defective parts of a light-emitting element structure that will become a micro-LED bonded to a bonded wafer via an adhesive to manufacture a bonded light-emitting element wafer, and a method for transferring micro-LEDs that can prevent defective micro-LEDs from being transferred.

[0046] As a result of extensive research into the above-mentioned problems, the inventors discovered that defective portions of a bonded wafer can be optically investigated to create removal map data, and that defective portions of light-emitting element structures included in a bonded light-emitting element wafer can be selectively removed by irradiating them with laser light based on the created removal map data, thereby completing the present invention.

[0047] That is, the present invention is a method for manufacturing a bonded light-emitting element wafer in which light-emitting element structures to become micro LEDs and a bonded substrate that is transparent to removal laser light are bonded via an adhesive that absorbs the removal laser light, comprising: a step of bonding the light-emitting element structures and the bonded substrate via the adhesive to obtain a bonded wafer; a step of optically inspecting defective portions of the bonded wafer and creating removal map data; and a step of irradiating the defective portions of the bonded wafer from the bonded substrate side based on the removal map data, causing the removal laser light to be absorbed by portions of the adhesive included in the defective portions, and sublimating the portions of the adhesive included in the defective portions, thereby removing the portions of the light-emitting element structures included in the defective portions, and obtaining the bonded light-emitting element wafer.

[0048] The present invention also provides a method for transferring micro-LEDs from a bonded light-emitting element wafer including the micro-LEDs to a transfer substrate, the method comprising: manufacturing a bonded light-emitting element wafer including the light-emitting element structure that has been subjected to the element separation process by the method for manufacturing a bonded light-emitting element wafer of the present invention; and transferring the light-emitting element structure as the micro-LED from the bonded light-emitting element wafer to the transfer substrate.

[0049] The present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto.

[0050] [Method for Manufacturing Bonded Light-Emitting Device Wafer] A schematic flowchart of the method for manufacturing a bonded light-emitting device wafer of the present invention is shown in Figure 1. The method for manufacturing a bonded light-emitting device wafer of the present invention generally includes the steps of obtaining a bonded wafer, creating removal map data, and applying removal laser light to defective parts of the bonded wafer based on the removal map data to remove parts of the light-emitting device structures included in the defective parts, thereby obtaining a bonded light-emitting device wafer.

[0051] Hereinafter, a method for manufacturing such a bonded light-emitting device wafer will be described in more detail with a specific example.

[0052] First Embodiment <Step of Obtaining Bonded Wafer> First, the step of obtaining a bonded wafer in this embodiment will be described with reference to FIGS. 2 to 5. FIG.

[0053] First, a first conductivity type GaAs buffer layer (not shown) is laminated on a first conductivity type GaAs starting substrate 1 shown in FIG. 2, and then a 0.1 μm thick first conductivity type Ga ｘ In １－ｘ A P (0.4≦x≦0.6) first etch stop layer and a 0.1 μm thick GaAs second etch stop layer of the first conductivity type are grown in sequence to form etch stop layer 2. Next, as shown in FIG. 2, a 1.0 μm thick (Al ｙ Ga １－ｙ ) ｘ In １－ｘ P (0.4≦x≦0.6, 0.6≦y≦1.0) first cladding layer 31, a 0.6 μm thick non-doped (Al ｙ Ga １－ｙ ) ｘ In １－ｘ P (0.4≦x≦0.6, 0≦y≦0.5) active layer 32, a 1.0 μm thick second conductivity type (Al ｙ Ga １－ｙ ) ｘ In １－ｘP (0.4≦x≦0.6, 0.6≦y≦1.0) second cladding layer 33, a 0.1 μm thick second conductivity type Ga ｘ In １－ｘ An EPW (epitaxial wafer) 100 is prepared, which has a light-emitting element structure 3 as an epitaxial functional layer formed by sequentially growing a P (0.5≦x≦1.0) intermediate layer (not shown) and a second-conductivity-type GaP window layer 34. Here, the first cladding layer 31 to the second cladding layer 33 are referred to as a DH structure. The light-emitting element structure 3 is processed into elements (dices) that will become micro-LEDs in a later process.

[0054] The film thicknesses exemplified above are merely examples, and the film thickness is merely a parameter that may be changed depending on the operating specifications of the device, and it goes without saying that the film thickness is not limited to the film thicknesses described here. Furthermore, it goes without saying that the concept of each layer not being a single-composition layer but having multiple composition layers within the composition ranges exemplified above also goes without saying. Furthermore, it goes without saying that the concept of each layer not being uniform in carrier concentration level but having multiple levels within each layer also goes without saying.

[0055] The active layer 32 may be composed of a single composition, or may have a structure in which multiple barrier layers and active layers are alternately stacked, and it goes without saying that both have similar functions, and it goes without saying that either one can be selected.

[0056] Next, benzocyclobutene (BCB) 4 is spin-coated onto the EPW 100 as an adhesive (thermosetting bonding material), and the light-emitting element structure 3 is placed face-to-face with a sapphire wafer, which is a substrate to be bonded 5, via the adhesive 4, and then thermocompression bonded to produce an EPW bonded substrate 200 shown in Fig. 3, in which the light-emitting element structure 3 of the EPW 100 and the sapphire wafer 5 are bonded via the BCB 4. In this embodiment, when applying the BCB by spin coating, the designed film thickness of the BCB 4 layer was 0.6 µm.

[0057] In this embodiment, sapphire is used as an example of the bonded substrate 5, but the bonded substrate 5 is not limited to sapphire, and it goes without saying that any material can be selected as long as it ensures transparency to the removal laser light described below and flatness. In addition to sapphire, quartz can also be selected.

[0058] In this embodiment, the BCB 4 is applied in a layered state, but it goes without saying that the adhesive 4 is not limited to a layered state. It goes without saying that the same results can be obtained by using a photosensitive BCB to pattern into isolated islands, lines, or other shapes and then performing the bonding process.

[0059] Next, the GaAs starting substrate 1 is removed by wet etching to expose the first etch stop layer, and then the etchant is switched to remove the second etch stop layer 2. This removes the etch stop layer 2 and exposes the first cladding layer 31. As shown in FIG. 4 , a bonded wafer (EP bonded substrate) 10 is produced in which the light-emitting element structure 3 including the DH layer and window layer 34 is bonded to the bonded substrate 5 via the adhesive 4.

[0060] In this embodiment, a BCB thickness of 0.6 μm is exemplified, but the thickness of the adhesive 4 is not limited to this thickness, and it goes without saying that the same effect can be obtained even if the thickness is thicker or thinner than this thickness.

[0061] Fig. 5 shows a schematic plan view of an example of a bonded wafer obtained in the process of obtaining a bonded wafer of this embodiment. The bonded wafer 10 shown in Fig. 5 includes a light-emitting element structure 3 bonded to a bonded wafer 5 via an adhesive (not shown). The bonded wafer 5 includes a light-emitting element structure non-bonding region 51 on its outer periphery where the light-emitting element structure 3 is not bonded.

[0062] <Step of Creating Removal Map Data> Next, a step of optically inspecting defective portions of the bonded wafer 10 and creating removal map data is carried out.

[0063] In this embodiment, first map data relating to defective parts, topology map data relating to defective parts, and second map data relating to defective parts are created, and these map data are used to create removal map data relating to defective parts.

[0064] The acquisition of each map data will be explained below.

[0065] [First Map Data] First, a laser beam with a wavelength of 325 to 532 nm and a spot diameter of 100 μm is irradiated at 25 μm intervals over the entire area of ​​the bonded wafer 10, and photoluminescence (PL) spectra are collected to create first map data. While any of the above-mentioned wavelengths can be selected as the laser wavelength, in this embodiment, a solid-state laser with an oscillation wavelength of 532 nm was used.

[0066] In this embodiment, the design wavelength of the EPW 100 is set to 632 nm, and positions within the range of 632±5 nm are set as pass points, and other wavelength ranges are set as fail points, to create first map data regarding defective parts, particularly parts with defective element characteristics.

[0067] In this embodiment, wavelength is used as an example of an item to be checked for defects, but it goes without saying that the criteria for judgment are not limited to wavelength alone. In many cases, convex defects are subjected to stress due to deformation, which may result in cracks. Because large stress increases the half-width of the peak, and the occurrence of cracks significantly reduces the PL intensity, the PL intensity or half-width may be used as criteria for judgment, or may be added to the criteria for creating the first map data.

[0068] [Topology Map Data] A laser with an oscillation wavelength of 532 nm is irradiated obliquely onto the surface of the bonded wafer 10 on the side of the light-emitting element structures 3 in Figure 4. Using a system in which a photodetector is placed in the reflection direction at the same angle as the laser incident angle, the laser is irradiated onto the entire surface of the wafer at 25 μm intervals, and deviations in the reflection angle are measured. Because the reflection angle deviates upward at convex portions of the light-emitting element structures 3 and downward at concave portions, topology data is collected from the deviations in the reflection angles. The height tolerance is used as a threshold, and topology map data is created in which points within the tolerance are passed and points outside the tolerance are failed.

[0069] 4 is photographed with a CCD camera from the side of the bonded substrate (sapphire substrate) 5, and pass / fail points are determined based on the color tone of the photograph. Fail points, which are poorly bonded, tend to be slightly whiter (lighter) in color than points where uniform bonding is achieved, and pass / fail is determined based on the contrast difference. Second map data is created for defective parts, particularly poorly bonded parts, which are determined as pass / fail using a 25 μm pitch mesh.

[0070] The defective parts of the first map data, topology map data, and second map data obtained as described above are superimposed to create removal map data. Although the positions of the three types of map meshes do not match, areas defined as defective parts in any one of the maps are defined as defective parts, and removal map data is created.

[0071] <A process of irradiating removal laser light onto defective portions of a bonded wafer based on removal map data, and removing portions of the light-emitting element structure included in the defective portions, thereby obtaining a bonded light-emitting element wafer> In this process, a bonded light-emitting element wafer is obtained by the procedure described below with reference to Figures 6 to 16.

[0072] First, as shown in Figure 6, a protective material 6 is applied to the surface of the bonded wafer 10 from which the starting substrate has been removed. In this embodiment, Hogomax (trademark: SDS, a propylene glycol monomethyl ether-polyvinyl alcohol-containing material) manufactured by DISCO Corporation is applied by spin coating as the protective material 6. However, the material for the protective material 6 is not limited to Hogomax, and any material that functions as a protective material and is easily removable can be selected. In addition to Hogomax, for example, polyvinyl acetate and polyvinyl alcohol are also suitable.

[0073] Next, the bonded wafers 10 coated with the protective material 6 are introduced into the laser processing section. During introduction, the bonded wafers 10 are held by a bonded wafer receiving jig 7 as shown in Fig. 7, for example, and introduced into the laser processing section. The bonded wafer receiving jig 7 shown in Fig. 7 has an opening region 72 in the center, the periphery of which forms a wafer receiving groove 71. When holding the bonded wafers 10, the light-emitting element structures 3 are positioned in the opening region 72, as shown in Fig. 8.

[0074] Furthermore, when introducing the bonded wafer 10, as shown in FIG. 8, the surface coated with the protective material 6 is introduced so that the surface is downward. In this embodiment, the case where the surface coated with the protective material 6 is downward is exemplified, but it goes without saying that the present invention is not limited to this downward position, and the surface may be set facing the top or side. However, when the surface coated with the protective material 6 faces downward, defective portions removed by sublimation of the BCB4 layer, as described below, tend to fall to the bottom of the wafer due to gravity, which is preferable because it reduces the amount of debris adhering to the surface coated with the protective material 6. However, since the protective material 6 is eventually removed, and the debris is removed along with it, it goes without saying that the introduction method is not limited to facing downward.

[0075] As shown in Fig. 5, the light emitting element structures 3 are not bonded to a width of about 1 to 2 mm around the periphery of the bonded wafer 10, leaving a light emitting element structure non-bonding region 51 where the bonded substrate (sapphire substrate) 5 or adhesive 4 is exposed. When the bonded wafer 10 is held with the application portion of the protective material 6 facing downward, the wafer receiving groove 71 of the jig 7 is designed to fit over this light emitting element structure non-bonding region 51, as shown in Fig. 8, and the wafer is held in place.

[0076] Next, a removal laser is irradiated from the side of the bonded substrate (sapphire substrate) 5 of the bonded wafer 10 onto the area defined as a defective portion based on the removal map data obtained earlier.

[0077] 9 shows a part of an example of the removal map data. The removal map data shown in FIG. 9 is centered on the defective portion 10A of the bonded wafer 10. The defective portion 10A includes the defective portion of the light-emitting element structure 3.

[0078] In this embodiment, the defective portion 10A is irradiated with a removal laser beam multiple times using a laser lift-off (LLO) method, as shown in Fig. 10. This results in multiple laser irradiation areas (per irradiation) 81, and as a whole, a laser irradiation area 82 that can be said to consist almost entirely of the defective portion 10A. In another aspect, the removal laser beam can be irradiated onto all of the defective portions 10A of the bonded wafer 10 (including the defective portions of the light-emitting element structures 3).

[0079] 11 shows a state in which a removal laser beam 83 is incident from the bonded substrate 5 side, the portion of the BCB (adhesive) 4 that was contained in the defective portion 10A of the bonded wafer 10 absorbs the removal laser beam 83, the portion of the BCB 4 that was contained in the defective portion 10A sublimes and turns into a gas, cracking the light-emitting element structure 3, and the adhesive strength of the BCB 4 to the bonded substrate 5 at the defective portion of the light-emitting element structure 3 decreases, causing the convex defective portion of the light-emitting element structure 3 to fall off. Because the defective portion cracks cleanly and falls off approximately along the cleavage line direction, the effect on adjacent good portions of the light-emitting element structure 3 is minimized.

[0080] In other words, by irradiating the defective portion 10A of the bonded wafer 10 with the removal laser light, the portion of the light-emitting element structure 3 that includes the defective portion 10A of the bonded wafer 10 (defective portion) can be removed.

[0081] A KrF excimer laser with a wavelength of 248 nm was used as the removal laser light 83, but the wavelength is not limited to this, and any laser light can be selected as long as it is transparent to the bonded substrate (sapphire substrate) 5 and absorbed by the adhesive (e.g., BCB) 4. For example, laser light (ultraviolet light) with a wavelength of 170 nm or more and 360 nm or less can be used as the removal laser light 83.

[0082] The previously described Fig. 10 is a conceptual diagram of removing a defective bond by the above-mentioned LLO (laser lift-off). In LLO, as shown in Fig. 10, a laser is irradiated along the outline of the removal area (the portion of the light-emitting element structure 3 that is included in the defective portion 10A of the bonded wafer 10). After the laser irradiation, a region 35 with a minimum area from which the defective portion has been removed can be obtained, as shown in Fig. 12. In other words, the defective portion can be completely removed, with only a slight protrusion remaining, which can be said to be almost entirely the defective portion.

[0083] Next, the bonded wafer 10 is removed from the laser processing section, and the surface coated with the protective material 6 is placed facing up, and washed with pure water to remove the protective material 6. This makes it possible to obtain a bonded light-emitting element wafer 20, as shown in Figure 13, in which the light-emitting element structures 3 including the regions 35 from which the defective portions have been removed and the bonded substrate 5 are bonded via the adhesive 4. The wafer 20 before the protective material 6 is removed can also be called a bonded light-emitting element wafer.

[0084] The light emitting element structure 3 is a structure that will become a micro LED, and can be subjected to element isolation processing, for example, as shown below. An example of processing will be described below.

[0085] A mask pattern is formed on the light-emitting element structure 3 by photolithography, and the light-emitting element structure 3 is subjected to element isolation processing by ICP. By this processing, the light-emitting element structure 3 becomes elements (light-emitting element structures that have been isolated, i.e., dices) 9 separated by isolation grooves 21, as shown in FIG. 14 . Gases used for ICP are, for example, chlorine and argon. The ICP processing is performed twice, for example, in a step of exposing the BCB4 layer and a step of exposing a portion of the main surface of the second cladding layer 33.

[0086] Although the present embodiment illustrates the case where a portion of the principal surface of the second cladding layer 33 is exposed, it goes without saying that the present invention is not limited to exposing a portion of the principal surface of the second cladding layer 33, and it goes without saying that the purpose of processing can be achieved as long as the active layer 32 is separated to a minimum extent. It goes without saying that the same effect can be obtained even when a portion of the principal surface of the GaP window layer 34 is exposed instead of exposing the second cladding layer 33.

[0087] After the element isolation process, a protective film 91 is formed as an end surface treatment, as shown in FIG. 15. In this embodiment, the protective film 91 is made of SiO ２ The protective film 91 was made of SiO ２ The material is not limited to SiN, and any material can be selected as long as it can protect the end face and has insulating properties. ｘ Alternatively, the protective film 91 may be made of a material such as titanium oxide or magnesium oxide. The protective film 91 has an opening 92 that exposes a portion of the principal surface of the first cladding layer 31, and an opening 93 that exposes a portion of the principal surface of the second cladding layer 33.

[0088] 16, electrodes 94 and 95 are formed in contact with the first conductivity type layer or the second conductivity type layer, respectively, and heat treatment is performed to form ohmic contacts. In this embodiment, the first conductivity type is designed to be N-type, and the second conductivity type is designed to be P-type, and a metal containing Au and Si is used for the N-type electrode 94 that contacts the first cladding layer 31, which is an N-type layer, through an opening 92, and a metal containing Au and Be is used for the P-type electrode 95 that contacts the second cladding layer 33, which is a P-type layer, through an opening 93.

[0089] In this embodiment, the metals Au and Si are used as the N-type electrode, but it goes without saying that the material is not limited to this and similar results can be obtained by using a metal containing Au and Ge.Furthermore, the metals Au and Be are used as the P-type electrode, but it goes without saying that the material is not limited to this and similar results can be obtained by using a metal containing Au and Zn.

[0090] Although BCB is used as the adhesive 4 in this embodiment, the material for the adhesive 4 used in the present invention is not limited to BCB as long as it absorbs the removal laser light 83. For example, when a bonded substrate 5 that is transparent to the removal laser light 83 having a wavelength of 170 nm or more and 360 nm or less is used, an adhesive 4 having an optical absorption edge in the wavelength range of 170 nm or more and 360 nm or less can be easily sublimated by the removal laser light 83 having a wavelength of 170 nm or more and 360 nm or less that can transmit through the bonded substrate 5. Examples of the adhesive 4 include, in addition to BCB, silicone resin, epoxy resin, SOG, polyimide, and amorphous fluorine-based resin (e.g., Cytop (registered trademark)). By using these, the light-emitting element structure 3 and the bonded substrate 5 can be firmly bonded.

[0091] (Second embodiment) In the second embodiment, the process for obtaining the bonded wafer 10 is the same as in the first embodiment, but differs from the first embodiment in that element isolation processing and electrode formation processing for the light-emitting element structure 3 are performed before the process for obtaining the removal map data.

[0092] The element isolation process and electrode formation process can be performed in the same manner as described with reference to Figures 14 to 16, except that the defective portions of the light-emitting element structure 3 are not removed. In the second embodiment, the element isolation (dicing) process and electrode attachment are performed while the convex defective portions are present in the light-emitting element structure 3, and therefore elements with defective shapes or dimensions may be formed in the defective portions. Such defective portions are later removed by irradiating a removal laser based on the removal map data.

[0093] However, in the second embodiment, unlike the first embodiment, the process is after dicing, which is not suitable for obtaining topology map data, and therefore only the first map data and the second map data are obtained.

[0094] Then, similarly to the first embodiment, the first map data and the second map data are used to superimpose the defective portions to generate removal map data.

[0095] When removing the defective portions, a protective material is applied to the surface of the elements obtained by separating the light-emitting element structures of the bonded wafer, as in the first embodiment. Then, a laser is irradiated from the sapphire substrate side using the same procedure as in the first embodiment to remove the defective portions. Thereafter, the protective material is washed with water and removed, as in the first embodiment. This makes it possible to obtain a bonded light-emitting element wafer in which the light-emitting element structures (elements) from which the defective portions have been removed are bonded to the bonded substrate via an adhesive.

[0096] The method for manufacturing a bonded light-emitting element wafer according to the present invention described above makes it possible to selectively remove defective portions of the light-emitting element structure easily without using mechanical techniques and without affecting good portions of the light-emitting element structure (e.g., other dice regions). Furthermore, according to the present invention, it is possible to remove all of the portions of the light-emitting element structure that were included in the defective portions of the bonded wafer.

[0097] In particular, by removing defective bonding portions (particularly convex defective portions) before starting device processes such as element isolation processing as in the first embodiment, it is possible to reduce photolithography precision defects around the defective portions.

[0098] Furthermore, in the second embodiment, defective portions of the light-emitting element structure can be selectively removed easily without using mechanical techniques and without affecting good portions (e.g., other die regions) of the light-emitting element structure.

[0099] <Method for transferring micro-LEDs> The method for transferring micro-LEDs of the present invention is a method for transferring micro-LEDs from a bonded light-emitting element wafer including micro-LEDs to a transfer substrate, in which a bonded light-emitting element wafer including light-emitting element structures that have been subjected to element separation processing is manufactured by the method for manufacturing a bonded light-emitting element wafer of the present invention described above, and the light-emitting element structures as micro-LEDs are transferred from this bonded light-emitting element wafer to a transfer substrate.

[0100] As described above, the method for manufacturing a bonded light-emitting element wafer of the present invention can selectively remove defective portions (e.g., defective bonding portions and portions with defective element characteristics) of light-emitting element structures included in a bonded light-emitting element wafer, thereby manufacturing a bonded light-emitting element wafer including light-emitting element structures from which the defective portions have been removed. Therefore, the method for transferring micro LEDs of the present invention can prevent the transfer of defective light-emitting element structures, i.e., defective micro LEDs.

[0101] EXAMPLES The present invention will be specifically explained below using examples and comparative examples, but the present invention is not limited to these.

[0102] First Example In the first example, a junction-type light-emitting element wafer was manufactured using the same procedure as in the first embodiment described above. Specifically, the procedure is as follows.

[0103] First, an EPW 100 having the EPW structure shown in FIG. 2 was obtained by the same procedure as previously described.

[0104] Next, BCB4 was applied onto the light emitting element structure 3 of EPW100 by spin coating so that the designed film thickness was 0.6 μm.

[0105] This was placed face-to-face on a sapphire wafer, which was the wafer to be bonded 5, and then thermocompression bonded to produce an EPW bonded substrate 200.

[0106] Next, the GaAs starting substrate 1 was removed by wet etching to expose the first etch stop layer, and the etchant was switched to remove the second etch stop layer, thereby removing the etch stop layer 2 and exposing the first cladding layer 31. A bonded wafer (EP bonded substrate) 10 (FIGS. 4 and 5) was produced in which the light-emitting element structure 3 including the DH layer and window layer 34 was bonded to the bonded substrate 5 via the adhesive 4.

[0107] Next, removal map data was created in the following procedure.

[0108] The entire area of ​​the bonded wafer 10 was irradiated with a laser having a wavelength of 532 nm and a spot diameter of 100 μm at a pitch of 25 μm, and PL spectra were collected to create map data. In this example, the design wavelength of the EPW was set to 632 nm, and first map data was created with positions within the range of 632±5 nm as pass points and other wavelength ranges as fail points.

[0109] Furthermore, a laser with an oscillation wavelength of 532 nm was irradiated obliquely onto the surface of the bonded wafer 10 on the side of the light-emitting element structure 3, and topology data was collected using a system in which a photodetector was placed in the direction of reflection at the same angle as the laser incident angle, and the laser was irradiated over the entire surface of the wafer at a pitch of 25 μm. Topology map data was created in which the height tolerance was used as a threshold, and points within the tolerance were considered pass points, and any other points were considered fail points.

[0110] Further, the bonded wafer 10 was photographed from the sapphire substrate 5 side with a CCD camera, and second map data was created in which pass / fail was judged based on the contrast difference with a 25 μm pitch mesh.

[0111] The defective portions of the first map data, topology map data, and second map data obtained as described above were superimposed to create removal map data.

[0112] Next, a protective material 6 was applied by spin coating using Hogomax (trademark) manufactured by DISCO Corporation onto the surface of the light emitting element structure 3 of the bonded wafer 10 from which the starting substrate had been removed, as shown in FIG.

[0113] The bonded wafer 10 coated with the protective material 6 was held by the bonded wafer receiving jig 7 shown in Fig. 7 as shown in Fig. 8, and introduced into the laser processing area with the surface coated with the protective material 6 facing downward. At this time, the wafer was held so that the wafer receiving groove 71 of the jig 7 was placed over the light-emitting element structure non-bonding region 51 where the sapphire substrate 5 was exposed, as shown in Fig. 8.

[0114] In the laser-processed portion, as shown in FIGS. 10 and 11, a KrF excimer laser with a wavelength of 248 nm was irradiated from the sapphire substrate 5 side only to the area defined as the defective portion 10A (and a small protruding portion that can be considered almost a defective portion) in accordance with the removal map data, thereby removing the defective portion.

[0115] Next, the wafer was taken out of the laser processing section and washed with pure water with the surface coated with the protective material 6 facing upward, thereby removing the protective material 6 as shown in FIG.

[0116] Next, a mask pattern was formed on the light-emitting element structure 30 by photolithography, and element isolation processing was performed by ICP using chlorine and argon gas. The ICP processing was performed twice: one step to expose the BCB layer 4 and one step to expose a part of the main surface of the second cladding layer 33. By this element isolation processing, the light-emitting element structure 30 was made into elements (light-emitting element structures processed for element isolation) 9 separated by the isolation grooves 21, as shown in FIG.

[0117] After the element isolation process, as shown in FIG. 15, the edge surface is treated with SiO ２ A protective film 91 is formed, and an opening 92 exposing a part of the main surface of the first cladding layer 31 and an opening 93 exposing a part of the main surface of the second cladding layer 33 are provided in the protective film 91 .

[0118] 16, electrodes 94 and 95 were formed in contact with the first conductivity type layer or the second conductivity type layer, respectively, and ohmic contacts were formed by performing heat treatment. In this example, the first conductivity type was designed to be N-type, and the second conductivity type was designed to be P-type, and a metal containing Au and Si was used for the N-type electrode 94 in contact with the first cladding layer 31, which is an N-type layer, and a metal containing Au and Be was used for the P-type electrode 95 in contact with the second cladding layer 33, which is a P-type layer.

[0119] In this manner, the junction-type light-emitting element wafer 20 of the first embodiment having the structure shown in FIG. 16 was obtained.

[0120] Second Example In a second example, a junction-type light-emitting element wafer was manufactured using the same procedure as in the second embodiment described above.

[0121] That is, in the second embodiment, the bonded light-emitting element wafer of the second embodiment was manufactured in the same manner as in the first embodiment, except that the element isolation processing and electrode formation processing for the light-emitting element structure 3 were performed before the process of obtaining the removal map data, and that the topology map data was not obtained.

[0122] Comparative Example In the comparative example, a bonded light-emitting element wafer of the comparative example was manufactured in the same manner as in the first example, except that the defective portions of the light-emitting element structures were not removed.

[0123] That is, in the comparative example, the process for obtaining the bonded wafer 10 was the same as in the first example, and the element isolation process and electrode formation process were carried out in the same manner as in the second example. However, unlike the second example, the comparative example did not create or remove map data, and therefore the defective portions of the light-emitting element structures remained as they were.

[0124] (Evaluation) Table 1 below shows a comparison between the removal rate of convex defects and the yield of the number of dice that did not cause any problems during final mounting.

[0125]

[0126] In the first example, when the convex defects were removed, the defective and good parts were connected in the wafer state, and when the BCB in the defective part sublimated to split the light-emitting device structure, cracks could occur in the adjacent good parts, resulting in a removal rate slightly exceeding 100%. In the second example, the defective parts were removed in the die state, so even when the BCB sublimated to split the light-emitting device structure, the impact did not propagate to the adjacent good parts due to the separation grooves between the dies, and the recognized defective area and the removal area roughly coincided, resulting in a removal rate of 100%. In the comparative example, no removal was performed, so the removal rate was 0%.

[0127] Table 1 above also shows the mounting die yield when 10 bonded light-emitting element wafers obtained by the methods of the first and second examples and the comparative example were put into the mounting (transfer) process.

[0128] The values ​​in parentheses represent the variation among 10 dice, and the values ​​outside parentheses represent the average. When the dice were subjected to the transfer process after the defective portions were removed using the method of the first or second embodiment, the average die yield (number of dice usable as devices / number of dice obtainable from one die) was over 90%. In contrast, in the comparative example in which the convex defective portions were not removed before transfer, stress concentration on the convex defective portions occurred during the process of pressing the dice against the transfer substrate during transfer, causing cracks, chips, and other damage not only to the defective dice but also to the surrounding dice. As a result, the yield was significantly lower than in the example in which almost only the convex defective areas could be removed.

[0129] As described above, the first and second embodiments, in which defective parts are removed by LLO before the die is transferred to the transfer substrate and then put into the mounting process, can improve the final mounting yield.

[0130] The present specification includes the following aspects: [1] A method for manufacturing a bonded light-emitting element wafer in which light-emitting element structures to be micro LEDs and a bonded substrate transparent to removal laser light are bonded via an adhesive that absorbs the removal laser light, the method comprising the steps of: bonding the light-emitting element structures and the bonded substrate via the adhesive to obtain a bonded wafer; optically inspecting defects in the bonded wafer and creating removal map data; and applying the removal laser light to the defects in the bonded wafer from the bonded substrate side based on the removal map data, causing parts of the adhesive included in the defects to absorb the removal laser light and sublimating the parts of the adhesive included in the defects, thereby removing the parts of the light-emitting element structures included in the defects, and obtaining the bonded light-emitting element wafer. [2] The method for manufacturing a bonded light-emitting element wafer according to [1], wherein the step of creating the removal map data comprises the steps of acquiring a photoluminescence spectrum of the bonded wafer and creating first map data for the defective portions using peak wavelength, peak intensity, and / or peak half-width as criteria, and photographing the bonded wafer from the bonded substrate side with a CCD camera and creating second map data for the defective portions based on the color tone of the image obtained by photographing, and the removal map data is created using the first map data and the second map data. [3] The method for manufacturing a bonded light-emitting element wafer according to [2], wherein the light-emitting element structures are subjected to element separation processing, and the removal map data is created for the bonded wafer including the light-emitting element structures subjected to element separation processing.[4] The method for manufacturing a bonded light-emitting element wafer according to [2], wherein the step of generating the removal map data further includes a step of irradiating a topology detection laser beam onto surfaces of the light-emitting element structures of the bonded wafer from an oblique direction to obtain topology data, and generating topology map data for the defective portions based on the topology data, and generating the removal map data for the defective portions using the first map data, the second map data, and the topology map data, and then performing element separation processing on the light-emitting element structures after removing portions of the light-emitting element structures included in the defective portions. [5] The method for manufacturing a bonded light-emitting element wafer according to any one of [1] to [4], wherein the removal laser beam is a laser beam having a wavelength of 170 nm or more and 360 nm or less. [6] The method for manufacturing a bonded light-emitting element wafer according to any one of [1] to [5], wherein the adhesive is an adhesive having an optical absorption edge in a wavelength range of 170 nm or more and 360 nm or less. [7] A method for manufacturing a bonded light-emitting element wafer according to any one of [1] to [6], characterized in that the adhesive is selected from the group consisting of benzocyclobutene, silicone resin, epoxy resin, SOG, polyimide, and amorphous fluorine-based resin. [8] A method for manufacturing a bonded light-emitting element wafer according to any one of [1] to [7], characterized in that a protective material is applied to the light-emitting element structures before removing the portion of the light-emitting element structure included in the defective portion. [9] A method for manufacturing a bonded light-emitting element wafer according to [8], characterized in that a polyvinyl acetate-containing protective material or a polyvinyl alcohol-containing protective material is used as the protective material.

[10] A method for transferring micro LEDs from a bonded light-emitting element wafer including micro LEDs to a transfer substrate, the method comprising: manufacturing a bonded light-emitting element wafer including the light-emitting element structures that have been subjected to element separation processing by the method for manufacturing a bonded light-emitting element wafer according to [3] or [4], and transferring the light-emitting element structures as the micro LEDs from the bonded light-emitting element wafer to the transfer substrate.

[0131] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A method for manufacturing a bonded light-emitting element wafer in which a light-emitting element structure to be a micro LED and a bonded substrate transparent to a removal laser beam are bonded via an adhesive that absorbs the removal laser beam, a step of bonding the light emitting element structure and the bonded substrate via the adhesive to obtain a bonded wafer; optically inspecting the bonded wafer for defects and creating removal map data; a step of irradiating the removal laser light from the bonded substrate side to the defective portion of the bonded wafer based on the removal map data, causing the portion of the adhesive included in the defective portion to absorb the removal laser light, and sublimating the portion of the adhesive included in the defective portion, thereby removing the portion of the light-emitting element structure included in the defective portion, thereby obtaining the bonded light-emitting element wafer; A method for producing a bonded light-emitting device wafer, comprising:

2. In the step of creating the removal map data, obtaining a photoluminescence spectrum of the bonded wafer and creating first map data on the defective portion based on a peak wavelength, a peak intensity, and / or a peak half-width as a criterion; taking an image of the bonded wafer from the bonded substrate side with a CCD camera, and creating second map data relating to the defective portion based on the color tone of the image obtained by photographing; Do the following:

2. The method for manufacturing a junction type light-emitting element wafer according to claim 1, wherein the removal map data is created using the first map data and the second map data.

3. performing element separation processing on the light emitting device structure; 3. The method for manufacturing a bonded light-emitting element wafer according to claim 2, wherein the removal map data is created for the bonded wafer including the light-emitting element structures that have been subjected to element separation processing.

4. In the step of creating the removal map data, A step of acquiring topology data by irradiating a topology detection laser beam from an oblique direction onto the surface of the light emitting element structure of the bonded wafer, and creating topology map data regarding the defective portion based on the topology data. Further, creating removal map data for the defective portion using the first map data, the second map data, and the topology map data; 3. The method for manufacturing a bonded light-emitting element wafer according to claim 2, further comprising the step of performing element separation processing on the light-emitting element structure after removing the portion of the light-emitting element structure that is included in the defective portion.

5. 2. The method for producing a junction-type light-emitting element wafer according to claim 1, wherein a laser beam having a wavelength of 170 nm or more and 360 nm or less is used as the removal laser beam.

6. 6. The method for manufacturing a bonded light-emitting element wafer according to claim 5, wherein an adhesive having a light absorption edge in a wavelength range of 170 nm or more and 360 nm or less is used as the adhesive.

7. 7. The method for producing a junction-type light-emitting element wafer according to claim 6, wherein the adhesive is selected from the group consisting of benzocyclobutene, silicone resin, epoxy resin, SOG, polyimide, and amorphous fluorine-based resin.

8. The method for manufacturing a bonded light-emitting element wafer according to any one of claims 1 to 7, characterized in that a protective material is applied onto the light-emitting element structure before removing the portion of the light-emitting element structure that is included in the defective portion.

9. 9. The method for manufacturing a junction-type light-emitting element wafer according to claim 8, wherein the protective material is a polyvinyl acetate-containing protective material or a polyvinyl alcohol-containing protective material.

10. A method for transferring micro LEDs from a junction type light emitting element wafer including micro LEDs to a transfer substrate, comprising: A bonded light-emitting device wafer including the light-emitting device structures subjected to the element separation process is manufactured by the method for manufacturing a bonded light-emitting device wafer according to claim 3 or 4, A method for transferring a micro-LED, comprising transferring the light-emitting element structure as the micro-LED from the bonded light-emitting element wafer to the transfer substrate.