Method for manufacturing semiconductor light-emitting device

Abstract

A method of manufacturing a semiconductor light emitting device is provided. In this method, a phosphor plate and a light-emitting element are bonded by surface activation bonding, and the phosphor plate and the light-emitting element are divided to produce respective semiconductor light-emitting layers, the production yield is improved. The upper surface of the light-emitting element plate is polished, the lower surface of the phosphor plate is polished, the phosphor plate is mounted on the light-emitting element, and heating and pressurizing are performed to form a laminate. A cutout is cut from the phosphor plate side to the laminated body at a position corresponding to the gap between the plurality of semiconductor light-emitting layers. Notches are formed in the laminated body of the gaps between the plurality of semiconductor light-emitting layers from the light-emitting element side. The laminated body between the front end of the cutout and the front end of the notch is cleaved to singulate the semiconductor light-emitting device. One of the cutout and the cutout is formed at a depth exceeding a joining surface of the phosphor plate and the light-emitting element plate.

Description

Technical Field

[0001] The present invention relates to a semiconductor light emitting device having a structure in which a semiconductor light emitting element and a phosphor plate are directly bonded together without the intermediary of a resin adhesive layer or the like. Background Art

[0002] Patent Documents 1 and 2 disclose methods for manufacturing a light-emitting device in which a phosphor plate is directly bonded to a light-emitting element by surface activated bonding (SAB) without using an adhesive. The light-emitting device manufactured by these manufacturing methods does not include an adhesive layer having a refractive index different from that of the light-emitting element or the phosphor plate (particularly an adhesive layer having a refractive index lower than that of the light-emitting element or the phosphor plate), thereby improving the light extraction efficiency from the light-emitting device.

[0003] Specifically, in the manufacturing method of Patent Document 1, the pre-singulated light-emitting elements are arranged on a relay substrate, and the bonding surfaces of the light-emitting elements and the phosphor ceramics are polished respectively, and then placed in a vacuum device. In the vacuum device, after irradiating each bonding surface with an ion beam of a rare gas element (at least one of He, Ne, Ar, and Kr), the bonding surfaces are brought into contact with each other and pressurized, thereby bonding. After the bonded light-emitting elements and phosphor ceramics are taken out of the vacuum device, the phosphor ceramics are cut into individual pieces for each light-emitting device by dicing.

[0004] On the other hand, Patent Document 2 discloses the following method: after directly bonding the substrate of the light-emitting element to the phosphor plate by surface activation bonding, both the light-emitting element and the phosphor plate are cut for each light-emitting device, thereby manufacturing individual light-emitting devices. This manufacturing method bonds an element substrate formed with a plurality of light-emitting elements to a phosphor plate by surface activation bonding. Before bonding, the element substrate is thinned by grinding and polishing, and a laser is irradiated to a position of the thinned element substrate that becomes a boundary between elements to form a crack. The phosphor plate is brought into contact with the element substrate formed with the crack, and bonded by surface activation bonding by applying pressure. Then, the phosphor plate is cut to the middle of the thickness of the phosphor plate by a blade. The position that becomes the boundary between elements is pressed from the light-emitting element side, and the element substrate is cut due to the crack, and at the same time, the semiconductor structure of the light-emitting element without the crack, the wiring structure, and the uncut portion of the phosphor plate are also cut to be singulated.

[0005] Prior art literature

[0006] Patent Literature

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-220675

[0008] [Patent Document 2] Japanese Patent Application Publication No. 2021-197542 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The manufacturing method of Patent Document 1 irradiates the bonding surface of the light-emitting element and the phosphor ceramic with an ion beam of a rare gas element to perform surface treatment, so it is necessary to arrange the light-emitting element and the phosphor ceramic in a vacuum device. After irradiation with the ion beam, the vacuum device is not opened to the atmosphere, and the bonding surface of the light-emitting element and the phosphor ceramic is brought into contact and bonded in a vacuum. Therefore, it is necessary to perform all operations such as surface activation treatment, alignment, substrate heating, and substrate weighting in a vacuum, which complicates the device structure and increases the price of the device, thereby increasing the cost of the product.

[0011] In addition, in the manufacturing method of Patent Document 1, the light-emitting elements are pre-monolithized and arranged, and after the phosphor ceramic is activated and bonded on the upper surface, the phosphor ceramic is cut and monolithicized for each light-emitting device. Therefore, the monolithic light-emitting device also has the problem that the size of the phosphor ceramic is inevitably larger than the light-emitting element.

[0012] On the other hand, although the manufacturing method of Patent Document 2 does not pre-single the light emitting element, a crack is introduced in the element substrate by laser in advance in order to cut the element substrate later, so the strength of the element substrate is reduced. Therefore, when the phosphor plate is brought into contact with the element substrate and pressurized for surface activation bonding, it is necessary to limit the pressurizing load in order to prevent the element substrate from cracking.

[0013] In addition, in the process after bonding the element substrate and the phosphor plate, the element substrate may be broken due to internal stress, external stress, etc. If the element substrate is warped or external force is applied, the element substrate and the phosphor plate may be separated at the bonding surface.

[0014] Furthermore, in order to cut the joined element substrate and phosphor plate, the phosphor plate is cut to the middle of its thickness, and no cracks or cuts are formed in the phosphor plate in the remaining thickness. Therefore, in the remaining thickness of the phosphor plate that has not been cut, when it is pressed for cutting, there is a possibility that the phosphor plate breaks at a position that is offset from the crack position of the element substrate, or that the crack spreads in a direction that is inclined relative to the direction of the crack of the element substrate and breaks. In the case where the phosphor plate breaks at a position that is offset from the crack position and direction of the element substrate or in an inclined direction, it becomes a defective product with a disordered side shape, thereby reducing the yield rate of the finished product.

[0015] An object of the present invention is to improve the manufacturing yield in a method of manufacturing individual semiconductor light-emitting layers by bonding a phosphor plate and a light-emitting element by surface activated bonding and then dividing the phosphor plate and the light-emitting element.

[0016] Means for solving problems

[0017] In order to achieve the above-mentioned purpose, the present invention provides a method for manufacturing a semiconductor light-emitting device, wherein a phosphor plate is bonded to a light-emitting element including a semiconductor light-emitting layer, and the phosphor plate absorbs light emitted from the semiconductor light-emitting layer and emits fluorescence, and the method for manufacturing the semiconductor light-emitting device comprises: a light-emitting element grinding step, in which the upper surface of the light-emitting element plate is ground, the light-emitting element plate including a plurality of semiconductor light-emitting layers arranged with gaps in the main plane direction; a phosphor grinding step, in which the lower surface of the phosphor plate is ground; a stacking step, in which the phosphor plate is mounted on the light-emitting element in a manner that the upper surface of the light-emitting element plate is opposed to the lower surface of the phosphor plate, and heating and pressurizing are performed to form a stacked body in which the phosphor plate is bonded to the light-emitting element plate; a cut forming step, in which a cut of a specified depth is cut from the phosphor plate side of the stacked body at a position corresponding to the gap between the plurality of semiconductor light-emitting layers; a notch forming step, in which a notch is formed at the gap between the plurality of semiconductor light-emitting layers from the light-emitting element side of the stacked body; and a singulation step, in which the stacked body between the front end of the cut and the front end of the notch is cut to singulate the semiconductor light-emitting device. The total depth of the cut and the notch is shallower than the thickness of the laminate, and one of the cut and the notch is formed to a depth exceeding the bonding surface between the phosphor plate and the light emitting element plate.

[0018] The total depth of the cut and the notch is shallower than the thickness of the laminate, and one of the cut and the notch is formed to have a depth exceeding the bonding surface between the phosphor plate and the light emitting element plate.

[0019] Effects of the Invention

[0020] According to the semiconductor light emitting device of the present invention, the manufacturing yield of the method of bonding the phosphor plate and the light emitting element by surface activated bonding and dividing the phosphor plate and the light emitting element to manufacture individual semiconductor light emitting layers can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 (a) and (b) are a cross-sectional view and a top view of the semiconductor light emitting device according to the first embodiment.

[0022] Figure 2 (a) to (g) are explanatory diagrams showing the manufacturing process of the semiconductor light emitting device according to the first embodiment.

[0023] Figure 3(a) to (e) are explanatory diagrams showing the manufacturing process of the semiconductor light emitting device according to the first embodiment.

[0024] Figure 4 Yes means Figure 3 (c) is a cross-sectional view of the shape of the stacked body after the manufacturing step.

[0025] Figure 5 (a) to (e) are the first embodiment. Figure 3 FIG. 2 is a diagram showing an example of the cross-sectional shape of the cutout 110 formed in the step (b).

[0026] Figure 6 (a) and (b) are a cross-sectional view and a top view of a semiconductor light emitting device according to a modified example of the first embodiment.

[0027] Figure 7 It is a cross-sectional view of a semiconductor light emitting device according to a second embodiment.

[0028] Figure 8 (a) to (g) are explanatory diagrams showing the manufacturing process of the semiconductor light emitting device according to the second embodiment.

[0029] Fig. 9 (a) to (e) are explanatory diagrams showing the manufacturing process of the semiconductor light emitting device according to the second embodiment.

[0030] Description of symbols

[0031] 1 Semiconductor light-emitting device

[0032] 10 Light-emitting element

[0033] 11 Component substrate

[0034] 12 Semiconductor light emitting layer

[0035] 13 Electrodes

[0036] 18 Buffer layer

[0037] 20 Phosphor Plate

[0038] 21 Buffer layer

[0039] 31 substrate

[0040] 32 Wiring

[0041] 40 Light reflective multilayer film

[0042] 50 Support base plate

[0043] 60 Heat-resistant adhesive layer

[0044] 70 Grinding Platform

[0045] 80 Grinding stage

[0046] 90 Adhesive layer

[0047] 100 Light emitting element board

[0048] 110a front end

[0049] 120 Adhesive Sheet

[0050] 130a Front End

[0051] 140 Roller

[0052] 150 Adhesive Sheet

[0053] 170 Laser

[0054] 171 Lens

[0055] 200 Pressurized Table

[0056] 301 Support base plate

[0057] 302 Adhesive layer

[0058] 310 Supporting platform

[0059] 341 Incision

[0060] 342 Gap

[0061] 350 Adhesive Sheet

[0062] 360 Adhesive Sheet

[0063] 370 Adhesive Sheet DETAILED DESCRIPTION

[0064] Embodiments of the present invention will be described below.

[0065] <<First embodiment>>

[0066] use Figure 1 to Figure 4 A method for manufacturing the semiconductor light emitting device according to the first embodiment will be described. Figure 1 (a) and (b) are a cross-sectional view and a plan view of the semiconductor light emitting device 1 manufactured by the manufacturing method of the first embodiment.

[0067] like Figure 1 As shown in FIG. 1 , in this embodiment, the phosphor plate 20 is bonded to the upper surface of the light emitting element 10 by surface activated bonding (SAB) to manufacture the semiconductor light emitting device 1. Figure 1In the embodiment, the light emitting element 10 is a flip chip type light emitting element, which is configured to include a semiconductor light emitting layer 12, an element substrate 11 arranged on the upper surface thereof, and a pair of electrodes 13 arranged on the lower surface of the semiconductor light emitting layer 12. A phosphor plate 20 is bonded to the upper surface of the element substrate 11. A buffer layer 21 is arranged on the bonding surface between the element substrate 11 and the phosphor plate 20. In addition, a part of the side surface of the light emitting element 10, the buffer layer 21 and the phosphor plate 20 is formed by cutting, and another part is formed by cleaving, but there is no sharp angle part, but a smooth shape, and it is covered with a light reflective multilayer film 40. In addition, the light reflective multilayer film 40 may not be provided. In addition, instead of forming the light reflective multilayer film 40, a structure in which the side surface is covered with a light reflective resin may be adopted.

[0068] exist Figure 1 In the examples (a) and (b) of FIG. 1 , the semiconductor light emitting device 1 is mounted on a substrate 31 having a pair of wirings 32 , and the pair of electrodes 13 of the light emitting element 10 is electrically connected to the pair of wirings 32 .

[0069] The phosphor plate 20 absorbs a part of the light emitted from the semiconductor light emitting layer 12 and emits fluorescence of a predetermined wavelength, thereby converting the wavelength of the light emitted from the semiconductor light emitting layer 12 and emitting the light from the upper surface.

[0070] The phosphor plate 20 is composed of, for example, a composite ceramic phosphor plate (Al2O3 / Ce:YAG) in which Ce-doped YAG phosphor particles are dispersed in an alumina ceramic matrix. The element substrate 11 is composed of a material that transmits light emitted by the semiconductor light emitting layer 12, such as sapphire (Al2O3).

[0071] Surface activated bonding is a bonding that utilizes the intermolecular forces of the substances on both sides of the bonding surface. The spacing between the molecules of the substances on both sides of the bonding surface needs to be a distance at which the intermolecular forces act (less than 0.5 nm). Therefore, in order to utilize surface activated bonding to bond the phosphor plate 20 and the component substrate 11, the surfaces of the phosphor plate 20 and the component substrate 11 need to be flattened to a roughness less than the distance at which the intermolecular forces act (less than 0.5 nm).

[0072] The composite ceramic phosphor plate constituting the phosphor plate 20 is composed of microcrystalline grains, and the hardness of the microcrystalline grains of the ceramic matrix and the microcrystalline grains of the phosphor are different. In addition, the hardness of the microcrystalline grains also varies depending on the direction in which the crystal axis of the microcrystalline is oriented in the phosphor plate 20. Therefore, even if the phosphor plate 20 is ground, a height difference (roughness) of about 1 / 20 of the particle size of the abrasive grains of the slurry used for grinding will remain on the surface.

[0073] Specifically, for example, in the case of a phosphor plate 20 of a composite ceramic phosphor plate (Al2O3 / Ce:YAG), when mirror polishing is performed using a slurry containing 1μm diamond particles as abrasives, due to the difference in hardness between Al2O3 and YAG, a height difference of about 50nm remains at the boundary of their grains. In addition, the matrix and phosphor particles of a YAG-based Ce:YAG phosphor plate (a plate in which YAG phosphor particles doped with Ce are dispersed in a YAG ceramic matrix) are ceramics of the same chemical formula, but due to the presence of microcrystals, even when polishing is performed using a slurry containing 50nm diamond particles as abrasives using a CMP (chemical mechanical polishing) method, a surface height difference of about ±2nm (roughness Ra ~ 1.5nm) remains. Therefore, it is difficult to flatten the surface of the phosphor plate 20 to a roughness below the distance (~0.5nm or less) at which intermolecular forces act separately.

[0074] Therefore, in the present embodiment, a buffer layer 18 is formed on the surface of the phosphor plate 20, and the buffer layer 18 is flattened to a roughness below the distance at which the intermolecular force acts (less than 0.5 nm). The CMP polishing of the buffer layer 18 uses a nano-slurry (diamond, silica or alumina) with a particle size of several nm to several tens of nm. For example, the phosphor plate 20 is polished by a CMP polishing (chemical mechanical polishing) method using a slurry containing diamond particles with a particle size of 50 nm as abrasive particles, and then the polished surface is further finely cut as needed, and organic contaminants on the surface are removed. After ultraviolet light (such as excimer light) treatment and plasma treatment are performed to activate the bonding surface (cut off the bonding of surface molecules to form dangling bonds), the buffer layer 21 is formed by a vapor phase growth method. The surface of the buffer layer 21 has an uneven shape following the unevenness of the polished surface of the phosphor plate 20 immediately after film formation. However, by performing CMP polishing on the buffer layer 21, it can be flattened to a roughness below the distance where intermolecular forces act (≤ 0.5 nm).

[0075] As the buffer layer 21, it is preferred to form a layer composed of an amorphous dielectric material. By making the buffer layer 21 amorphous, the flatness after CMP polishing can be improved compared to the case where it contains microcrystals. As the buffer layer 21, for example, it is preferred to form an amorphous Al2O3 thin film (for example, a film thickness of about 200nm to 1000nm) by EB (electron beam) evaporation. In the CMP polishing of the buffer layer 21, for example, a platform equipped with a relatively low hardness polishing wheel and a silica-based slurry are used to implement CMP polishing.

[0076] In addition, the buffer layer 21 is not limited to an amorphous Al2O3 film, and can be any material as long as it is an inorganic material that meets the following conditions: it is transparent to the light emitted by the semiconductor light-emitting layer 12 (for example, there is no light absorption in the entire region of the white spectrum), the thermal expansion coefficient and the refractive index of light are close to those of the element substrate 11 and the phosphor plate 20, the material has excellent thermal conductivity, good acid and alkali resistance, and little stress corrosion, and can be flattened by grinding to a roughness below the distance where intermolecular forces act (below ~0.5nm).

[0077] For example, dielectric materials such as Al oxide (Al 2 O 3 , etc.), SiO 2 , Nb 2 O 5 , Ta 2 O 5 , TiO 2 , Y 2 O 3 , MgO and ZrO 2 can be preferably used as the material of the buffer layer 21 .

[0078] In addition, in order to make the buffer layer 21 flattened by grinding to a roughness below the distance where the intermolecular force acts (~0.5nm or less), it is preferably amorphous, and particularly preferably amorphous without microcrystals. In addition, when the buffer layer 21 contains microcrystals, the size of the microcrystal grains is preferably 50nm or less, and particularly preferably 10nm or less.

[0079] In addition, by using an amorphous buffer layer 21, the hardness is lower than that of a buffer layer 21 composed of a single crystal, and the buffer layer 21 has flexibility when the phosphor plate 20 provided with the buffer layer 21 is brought into contact with the element substrate 11. Therefore, by applying pressure, the buffer layer 21 is plastically deformed and can be closely attached to the surface shape of the element substrate 11, so that surface activation bonding can be easily performed.

[0080] In addition, the buffer layer 21 preferably does not contain voids. If voids are contained, the surface flatness of the buffer layer 21 deteriorates, which becomes a factor that reduces the bonding strength of the surface activated bonding.

[0081] The film forming method of the buffer layer 21 is not limited to the EB evaporation method, and other film forming methods such as sputtering, CVD (chemical vapor deposition) method, and ALD (atomic layer deposition) method can be used. The buffer layer 21 can be formed into an amorphous buffer layer by adjusting the film forming conditions such as the film forming temperature.

[0082] The buffer layer 21 may have a thickness that can flatten the roughness to a distance at which intermolecular forces act (≤ 0.5 nm), and is preferably 50 nm to 2 μm, and particularly preferably about 200 nm to 600 nm.

[0083] In addition, the phosphor plate 20 is not limited to the composite ceramic phosphor plate (Al2O3 / Ce:YAG), and a phosphor plate composed of a single crystal of Ce:YAG, a phosphor ceramic plate of YAG matrix (YAG / Ce:YAG), or glass can be used. In addition, in the composite ceramic phosphor plate, the particle size and density of the YAG particles can also be appropriately selected according to the application.

[0084] As the light emitting element 10 , for example, a blue LED may be used in which the element substrate 11 is any of a sapphire substrate, a spinel substrate, and a GaN substrate, and the semiconductor light emitting layer 12 includes a GaN layer.

[0085] In addition, it is preferable to provide the buffer layer 21 on the phosphor plate 20 side in the manufacturing process, but the buffer layer 21 may be provided on both the phosphor plate 20 and the element substrate 11. In addition, the buffer layer 21 may be provided only on the element substrate 11. In addition, in the present embodiment, when manufacturing the semiconductor light-emitting device 1, a larger phosphor plate 20 of a plurality of semiconductor light-emitting devices 1 is bonded to a larger element substrate 11 having a continuous structure of a plurality of light-emitting elements 10 to form a stacked body. Then, in order to divide the stacked body at the boundary position of the plurality of semiconductor light-emitting devices 1 to form each semiconductor light-emitting device 1, a cut is made from the phosphor plate 20 side of the stacked body by cutting or the like, and a notch is formed from the semiconductor light-emitting layer 12 side of the element substrate 11. At this time, the cut is formed to penetrate the buffer layer 21. Specifically, the cut is formed to penetrate the buffer layer 21 and reach the element substrate 11. That is, the cut is formed to penetrate the bonding surface between the phosphor plate 20 and the light-emitting element plate 100 and reach the light-emitting element plate 100 (the element substrate 11 in this case). As a result, the internal stress of the joint surface between the phosphor plate 20 and the element substrate 11 is released, and when a force is applied from the outside, the stress is prevented from being concentrated on the joint surface, and the element substrate 11 and the phosphor plate are prevented from being peeled off at the joint surface. As a result, the manufacturing yield is improved. This will be described in detail below in the description of the manufacturing method.

[0086] <Manufacturing method>

[0087] Figure 2 and Figure 3 It is a figure explaining the manufacturing process of this manufacturing method. Figure 4 Yes means Figure 3 (c) is a cross-sectional view of the shape of the stacked body after the manufacturing step.

[0088] use Figure 2 to Figure 4 The manufacturing process will be described.

[0089] (Polishing Step of Light Emitting Element 10)

[0090] First, prepare the light emitting element panel 100, such as Figure 2As shown in (a), the light-emitting element plate 100 has a plurality of semiconductor light-emitting layers 12 and electrodes 13 arranged with gaps along the main plane direction on the lower surface of a continuous element substrate 11. The spacing between the plurality of semiconductor light-emitting layers 12 of the light-emitting element plate 100 is designed so that individual light-emitting elements 10 can be obtained by dividing the element substrate 11 at the boundaries of adjacent light-emitting elements 10.

[0091] like Figure 2 As shown in (a) , the support substrate 50 is bonded to the plurality of arranged semiconductor light emitting layers 12 of the light emitting element panel 100 via the heat resistant adhesive layer 60 .

[0092] like Figure 2 As shown in (b) , the back side (the surface opposite to the side to which the semiconductor light emitting layer 12 is bonded) of the support substrate 50 is fixed to the polishing stage 80 - 1 via the adhesive layer 90 - 1 .

[0093] Prepare a grinding platform 70-1, use a slurry containing diamond abrasives, and use the grinding platform 70-1 to cut and grind the back side of the element substrate 11 of the light-emitting element plate 100 to make it thinner, and flatten the surface of the element substrate 11 to a roughness (Ra) below the distance where intermolecular forces act (below ~0.5nm).

[0094] Specifically, for example, a grinding process, a mechanical polishing process, and a CMP polishing process are sequentially performed using the polishing platen 70 - 1 .

[0095] For example, in the grinding process, a grinding stone with a grain size of #230 is used to reduce the thickness (for example, 830 μm) of the element substrate 11 to 150 μm by a grinding device. The roughness (Ra) of the element substrate 11 after grinding is about 200 nm.

[0096] Next, in the mechanical grinding process, the surface of the element substrate 11 having a thickness of 150 μm after the grinding process is subjected to the first mechanical grinding using a slurry containing diamond abrasive grains having a particle size of 6 μm, thereby making the roughness (Ra) of the element substrate 11 less than 50 nm. Through this first mechanical grinding process, the surface damage and crack layer generated in the grinding process can be removed. The thickness of the element substrate after the first mechanical grinding process is about 120 μm. Then, a second mechanical grinding is performed using a slurry containing diamond abrasive grains having a particle size of 1 μm, thereby making the roughness (Ra) of the element substrate 11 less than 10 nm.

[0097] Next, in the CMP polishing step, CMP polishing is performed using a slurry containing diamond abrasive grains having a particle size of 50 nm, thereby reducing the roughness (Ra) of the element substrate 11 to less than 0.5 nm.

[0098] Through these steps, the surface of the element substrate 11 can be flattened to a roughness (Ra) of 0.5 nm, which is smaller than the distance at which intermolecular forces act (≤ 0.5 nm).

[0099] Then, if Figure 2 As shown in (c), the surface of the polished element substrate 11 is subjected to ultraviolet light (excimer light) treatment and plasma treatment.

[0100] Specifically, the polished surface of the element substrate 11 is irradiated with ultraviolet light (excimer light: wavelength (175±15) nm) and cleaned.

[0101] Next, a light-emitting element plate 100 is arranged in a vacuum device, and a plasma of any one of Ar, O2, N2 or a mixed gas of two or more is generated by high-frequency power (100W to 450W, preferably 250W to 350W), and the polished surface of the element substrate 11 is subjected to plasma treatment for a specified treatment time (1 minute to 10 minutes, preferably 3 minutes to 6 minutes).

[0102] (Polishing Step of Phosphor Plate 20)

[0103] On the other hand, Figure 2 As shown in (d), a plurality of phosphor plates 20 of a continuous size for the semiconductor light emitting devices 1 are prepared and fixed to the polishing stage 80 by the adhesive layer 90 .

[0104] The grinding platform 70 - 2 is prepared, and the surface of the phosphor plate 20 is ground by the grinding platform 70 - 2 using slurry containing diamond abrasive grains.

[0105] Specifically, for example, a mechanical polishing process is performed, and a CMP polishing process is sequentially performed using the polishing platform 70 - 2 .

[0106] In the mechanical polishing step, the surface of the phosphor plate 20 is mechanically polished using a slurry containing diamond abrasive grains with a particle size of 6 μm, and then mechanically polished using a slurry containing diamond abrasive grains with a particle size of 1 μm, thereby reducing the roughness (Ra) of the element substrate 11 to less than 10 nm.

[0107] Next, in the CMP polishing step, CMP polishing is performed using a slurry containing diamond abrasive grains with a particle size of 50 nm to reduce the roughness (Ra) of the phosphor plate to less than 1 nm. The CMP polishing step is performed as necessary.

[0108] Thereafter, the polishing stage 80 - 2 is removed from the phosphor plate 20 .

[0109] (Film Formation and Polishing of Buffer Layer 21)

[0110] Then, if Figure 2 As shown in (e) , a buffer layer 21 is formed on the polished surface of the phosphor plate 20 .

[0111] For example, an amorphous Al 2 O 3 film with a thickness of 600 nm is formed by EB evaporation.

[0112] like Figure 2 As shown in (f) of FIG. 8 , the surface of the phosphor plate 20 opposite to the surface on which the buffer layer 21 is formed is fixed to the polishing stage 80 - 3 via an adhesive layer 90 - 3 .

[0113] A polishing platform 70-3 is prepared, and a slurry containing silica particles of several nm to several tens of nm is used to perform CMP polishing on the surface of the buffer layer 21 of the phosphor plate 20 using the polishing platform 70-3 to make the roughness (Ra) less than 0.5 nm. This roughness is the roughness (Ra) below the distance (~0.5 nm or less) where the intermolecular force acts.

[0114] Then, if Figure 2 As shown in (g), the surface of the polished phosphor plate 20 is subjected to ultraviolet light (excimer light) treatment and plasma treatment. The conditions of these treatments are the same as those of Figure 2 is the same as (c), so the description is omitted.

[0115] Preferably, Figure 2 (c) The ultraviolet light (excimer light) treatment and plasma treatment of the element substrate 11 Figure 2 The ultraviolet light (excimer light) treatment and plasma treatment of the phosphor plate 20 in (g) are completed simultaneously.

[0116] After the plasma treatment, the light emitting element 10 and the phosphor plate 20 are taken out from the vacuum apparatus.

[0117] (Joining process)

[0118] Then, if Figure 3 As shown in (a), the light emitting element plate 100 supported by the supporting substrate 50 is mounted on the heating and pressing stage 200, and the phosphor plate 20 is mounted thereon. At this time, the light emitting element plate 100 is mounted in such a manner that the surface of the element substrate 11 that has been polished, treated with ultraviolet light (excimer light) and plasma is in contact with the surface of the buffer layer 21 that has been polished, treated with ultraviolet light (excimer light) and plasma is in contact with the phosphor plate 20.

[0119] Under normal pressure, using a heating and pressing stage 200, Figure 3In the state (a), the light emitting element plate 100 and the phosphor plate 20 are heated to 100°C to 300°C, preferably to 150°C to 250°C, a load (for example, 2 MPa or more, preferably 10 MPa or more) is applied to the light emitting element plate 100 and the phosphor plate 20, and the heating and pressurizing state is maintained for more than 30 minutes, preferably more than 2 hours, and the light emitting element plate 100 and the phosphor plate 20 are bonded by surface activated bonding. Thus, the element substrate 11 and the phosphor plate 20 are bonded to each other through the buffer layer 21 by surface activated bonding to form a laminate.

[0120] Alternatively, the light emitting element plate 100 and the phosphor plate 20 may be placed in a vacuum device and bonded together by heating and pressurizing them under reduced pressure.

[0121] (Incision Forming Process)

[0122] like Figure 3 As shown in (b), a groove-shaped cutout 110 of a predetermined depth is formed at a position corresponding to the gap between the plurality of semiconductor light-emitting layers from the phosphor plate 20 side of the laminate.

[0123] The cutout 110 reaches the buffer layer 21 and penetrates the buffer layer 21. The cutout 110 penetrates the bonding surface between the phosphor plate 20 and the light emitting element plate 100 and reaches the element substrate 11.

[0124] Specifically, the cutout 110 is formed by blade dicing using a blade having a blade width of 20 μm to 500 μm. The cutout 110 is formed to extend beyond the phosphor plate 20 and the buffer layer 21 and penetrate into the element substrate 11 to a depth of 1 μm to 50 μm, preferably 1 μm to 20 μm.

[0125] In addition, if Figure 5 As shown in (a) to (e), the cross-sectional shape of the cutout 110 may be a rectangle ( Figure 5 (a)), trapezoidal ( Figure 5 (b)), a rounded rectangle ( Figure 5 (c)), rounded trapezoid ( Figure 5 (d)), parabolic ( Figure 5 (e)) of any one, but preferably a rounded shape ( Figure 5 (c) to (e)), particularly preferably a parabolic shape ( Figure 5 (e)).

[0126] The cross section is parabolic ( Figure 5The cutout 110 of (e)) is a shape that is closest to the lower surface (surface on which the semiconductor light emitting layer 12 is mounted) of the element substrate 11 at a point at the front end 110a of the cutout cross section. Therefore, in the singulation process described later, by applying force to the stacked body, stress is concentrated at a point at the front end of the front end 110a, and the element substrate 11 can be divided by cleavage or the like starting from this position.

[0127] In addition, although the cutout 110 is formed by blade cutting here, the cutout 110 may also be formed by laser cutting.

[0128] (Notch Forming Process)

[0129] Next, if Figure 3 As shown in (c), the support substrate 50 is removed from the semiconductor light emitting layer 12, and the adhesive sheet 120 is adhered to the phosphor plate 20 side of the laminate.

[0130] From the light emitting element panel 100 side of the stacked body, groove-shaped notches 130 are formed in the element substrate 11 at the gaps between the plurality of semiconductor light emitting layers 12 .

[0131] Specifically, for example, a laser scribing device is used to focus laser light 170 through lens 171 and irradiate the element substrate 11 at the gaps between the plurality of semiconductor light emitting layers 12 to form groove-shaped notches 130 .

[0132] The sum of the depth of the notch 130 and the depth of the cut 110 is shallower than the thickness of the laminate. The laminate is divided by rupture such as cleavage.

[0133] In addition, a laser scribing device may be used to form a protective film on the surface of the semiconductor light emitting layer by coating before forming the notch 130. The protective film prevents dirt generated by laser scribing from adhering to the surface of the semiconductor light emitting layer. The protective film can be removed by water washing in a subsequent process.

[0134] Nano-pulse or pico-pulse laser is preferably used as the laser 170. As the wavelength of the laser 170, a wavelength of 355 nm can be used.

[0135] The shape of the notch 130 is preferably a wedge shape, and the width of the notch 130 is preferably 10 μm or less, and particularly preferably 2 μm or less. The depth of the notch 130 is preferably 2 μm or more, and particularly preferably 5 μm or more.

[0136] Thus, the laminate becomes Figure 4 shape.

[0137] After the notches 130 are formed, the laminate is washed with water and organic cleaning to remove contaminants caused by laser scribing.

[0138] In addition, Figure 3 In (c), the laser 170 is irradiated from the semiconductor light emitting layer 12 side, but the laser 170 may be irradiated from the phosphor plate 20 side. Figure 3 The notch 130 is formed at the position of the notch 130 of the element substrate 11 in (c). For example, the cut surface can be formed on the element substrate 11 using a stealth dicing device.

[0139] Here, since the intervals between the semiconductor light emitting layers 12 are narrow, the notches 130 are formed by laser scribing. However, the notches 130 may be provided by blade dicing using a thin blade.

[0140] (Singularization process)

[0141] like Figure 3 As shown in (d), the laminate is attached to the adhesive sheet 150 with the light emitting element 10 facing downward.

[0142] When the entire surface of the laminated phosphor plate 20 is uniformly pressed by the roller 140, the front end 110a of the cutout 110 and the front end 130a of the notch 130 (see Figure 5 (e)) between the element substrate 11 is cut and broken (refer to Figure 5 (e)). Thus, the semiconductor light emitting device 1 is individualized.

[0143] In addition, since the thermal expansion coefficient of the phosphor plate 20 is greater than that of the element substrate 11, Figure 3 In the step (c), by appropriately setting the conditions when forming the notch 130 by irradiating the laser 170, the element substrate 11 between the notch 130 and the cut 110 can be cleaved and separated into individual pieces by only forming the notch 130 by irradiating the laser 170. In this case, the step of applying force by the roller 140 can be omitted.

[0144] (Step of spacing semiconductor light emitting devices 1)

[0145] Finally, the adhesive sheet 150 is stretched (expanded) in the main plane direction to increase the intervals between the semiconductor light emitting devices 1 on the adhesive sheet 150. Thus, the semiconductor light emitting devices 1 are ready for operation.

[0146] Through the above steps, the semiconductor light emitting device 1 can be manufactured (see Figure 1 ).

[0147] As described above, in this embodiment, by providing the buffer layer 21 and polishing the buffer layer 21 , the phosphor plate 20 can be bonded to the light-emitting device by the surface activated bonding method without being affected by the crystal grains of the phosphor plate 20 .

[0148] In addition, in this embodiment, for the laminate formed by surface-activated bonding of the element substrate 11 of the light-emitting element plate 100 and the phosphor plate, the cut 110 is set to a depth reaching the buffer layer 21, thereby preventing peeling at the bonding surface due to internal stress or external force on the bonding surface. Furthermore, in the cutting when the cut 110 is set, the substrate cutting (about 5μm to 20μm) after penetrating the bonding surface is almost not performed, so a narrow cutting blade can be used. Therefore, the width of the cut 110 set between the light-emitting elements can be formed to be smaller.

[0149] In addition, by providing the notch 130 between adjacent semiconductor light-emitting layers, the element substrate therebetween can be easily and precisely divided by cleavage or the like at the position connecting the notch 130 and the cutout 110. Therefore, the phosphor plate and the element substrate can be accurately divided and singulated into individual semiconductor light-emitting devices 1, thereby improving the manufacturing yield.

[0150] In addition, in this embodiment, if Figure 1 As shown in FIG. 1 , a semiconductor light emitting device having a pair of electrodes 13 is manufactured. Figure 6 As shown in (a) and (b) of FIG. 1 , a structure including two pairs of electrodes 13 in one semiconductor light emitting device can also be manufactured through the above-mentioned manufacturing process.

[0151] <<Second embodiment>>

[0152] In a second embodiment, if Figure 7 As shown in FIG. 1 , a semiconductor light emitting device without the element substrate 11 is manufactured. Figure 8 The manufacturing method is described below. Figure 8 In Figure 2 and Figure 3 The description of the same manufacturing method is omitted.

[0153] like Figure 8 As shown in (a), a light emitting element panel 100 in which a semiconductor light emitting layer 12 is formed on the front surface of an element substrate 11 is prepared.

[0154] like Figure 8 As shown in (b) of FIG. 1 , the semiconductor light emitting layer 12 is processed into the shape of the semiconductor light emitting layer 12 of each semiconductor light emitting device by etching or the like. Then, a pair of electrodes 13 are formed on each of the semiconductor light emitting layers 12 .

[0155] like Figure 8 As shown in (c) , the electrode 13 of the semiconductor light emitting layer 12 is fixed to the light-transmitting support substrate 301 by an adhesive layer 302 made of a resin adhesive. The support substrate 301 is mounted on a support stand 310 .

[0156] like Figure 8As shown in (d) of FIG. 1 , the element substrate (sapphire substrate) 11 is irradiated with laser light such as excimer laser light, and the element substrate 11 is removed by laser stripping. Figure 8 As shown in (e), the semiconductor light emitting layer 12 is exposed.

[0157] exist Figure 8 In (e), the exposed semiconductor light emitting layer 12 is flattened by a polishing process, and subjected to ultraviolet light (excimer light) treatment and plasma treatment. Figure 2 The steps (a) to (c) are similarly performed by polishing, ultraviolet light (excimer light) treatment, and plasma treatment.

[0158] exist Figure 8 In the step (f), the phosphor plate 20 is ground, a buffer layer 21 is formed on the ground surface, and the surface of the buffer layer 21 is ground and subjected to ultraviolet light (excimer light) treatment and plasma treatment. Figure 2 These treatments are carried out in the same manner as in steps (d) to (g).

[0159] exist Figure 8 In step (g), the phosphor plate 20 is mounted on the semiconductor light emitting layer 12 in contact with the buffer layer 21, and heating and pressurization are performed to surface activate and bond the semiconductor light emitting layer 12 and the phosphor plate 20. Figure 3 This step is carried out in the same manner as step (a).

[0160] Then, in Fig. 9 In the step (a), ultraviolet light is irradiated to generate bubbles, thereby removing the support substrate 301 and the adhesive layer 302 from the semiconductor light emitting layer 12 .

[0161] In addition, a substrate other than a light-transmitting substrate may be used as the support substrate 301. For example, when a substrate such as Si is used as the support substrate 301 and the semiconductor light-emitting layer 12 is mounted via an adhesive layer 302 made of a metal material, a sacrificial layer made of silver is formed as an intermediate layer of the adhesive layer 302, and the sacrificial layer is dissolved with nitric acid or the like, thereby removing the support substrate 301 and the adhesive layer 302.

[0162] exist Fig. 9 In the step (b) of the first embodiment, the adhesive sheet 350 is adhered to the electrode 13 side of the semiconductor light emitting layer 12, and the cutout 341 is formed in the phosphor plate 20. Figure 3 The step (b) is performed in the same manner as in the first embodiment, but the depth of the cutout 341 is formed so as not to reach the buffer layer 21 , which is different from the first embodiment.

[0163] exist Fig. 9In step (c), the adhesive sheet 350 is removed and the adhesive sheet 360 is bonded to the phosphor plate 20. In the buffer layer 21 in the gaps between the plurality of semiconductor light emitting layers 12, a laser scribing device is used to focus the laser 170 through the lens 171 from the side where the semiconductor light emitting layer 12 is arranged, thereby forming a groove-shaped notch 342. Figure 3 The step (c) is performed in the same manner as in the first embodiment, but is different from the first embodiment in that the notches 342 are directly formed in the buffer layer 21 .

[0164] Then, the adhesive sheet 360 is removed, and the adhesive sheet 370 is bonded to the electrode 13 side of the semiconductor light emitting layer 12 .... Figure 3 The steps (d) and (e) are carried out in the same manner. Fig. 9 (d)~ Fig. 9 In step (e), each semiconductor light-emitting device is singulated.

[0165] As described above, in the second embodiment, even in the light emitting element 10 from which the element substrate 11 is removed, the phosphor plate 20 can be bonded by surface activated bonding.

[0166] In the second embodiment, the notch 342 is provided in the buffer layer 21 , so that stress can be prevented from being applied to the light emitting element 10 .

[0167] The other effects of the second embodiment are the same as those of the first embodiment.

[0168] Furthermore, in the second embodiment, Fig. 9 In step (c), the notches 342 are formed in the buffer layer 21 between the plurality of semiconductor light emitting layers 12 from the side where the semiconductor light emitting layer 12 is disposed. Alternatively, the notches 342 may be formed at the front ends of the notches 341 .

[0169] In the second embodiment, the notches 342 are formed, but since the buffer layer 21 is a thin film, the notches 342 can be formed arbitrarily as needed. That is, the notches 342 may not be provided.

[0170] The technology of the semiconductor light emitting device of this embodiment can be used for a lamp light source unit or a white light source module.

Claims

1. A method for manufacturing a semiconductor light-emitting device, wherein a phosphor plate is bonded to a light-emitting element including a semiconductor light-emitting layer, and the phosphor plate absorbs light emitted from the semiconductor light-emitting layer to emit fluorescence, characterized in that: The method for manufacturing the semiconductor light emitting device comprises: a light emitting element grinding step of grinding an upper surface of a light emitting element plate including a plurality of semiconductor light emitting layers arranged with gaps therebetween in a main plane direction; A phosphor grinding step of grinding the lower surface of the phosphor plate; A lamination step of placing the phosphor plate on the light emitting element in a manner such that the upper surface of the light emitting element plate faces the lower surface of the phosphor plate, heating and pressurizing the phosphor plate to form a laminated body in which the phosphor plate is bonded to the light emitting element plate; a cutout forming step of cutting a cutout of a predetermined depth from the phosphor plate side of the stacked body at a position corresponding to the gap between the plurality of semiconductor light emitting layers; a notch forming step of forming a notch at the gap between the plurality of semiconductor light emitting layers from the light emitting element side of the stack; as well as a singulation step of cutting the stacked body between the front end of the cutout and the front end of the notch to singulate the semiconductor light emitting device, The sum of the depth of the cut and the depth of the notch is shallower than the thickness of the laminate, One of the cutout and the notch is formed to have a depth exceeding a bonding surface between the phosphor plate and the light emitting element plate.

2. The method for manufacturing a semiconductor light emitting device according to claim 1, characterized in that: The method for manufacturing a semiconductor light emitting device further comprises a film forming step before the lamination step, in which a buffer layer composed of an inorganic substance is formed on at least one of the upper surface of the light emitting element plate and the lower surface of the phosphor plate. In the lamination step, the phosphor plate is mounted on the light emitting element in such a manner that the upper surface of the light emitting element plate and the lower surface of the phosphor plate face each other via the buffer layer, and heating and pressurizing are performed, and the phosphor plate is bonded to the light emitting element plate via the buffer layer, thereby forming the laminated body. One of the cutout and the notch is formed to have a depth in the buffer layer exceeding the bonding surface between the phosphor plate and the light emitting element plate.

3. The method for manufacturing a semiconductor light emitting device according to claim 1, wherein: The light emitting element includes an element substrate, and the light emitting element panel is a structure in which a plurality of semiconductor light emitting layers are fixed to the lower surface of the common element substrate via the gap. The light emitting element grinding step is a step of grinding the upper surface of the element substrate common to the light emitting element panels. In the lamination step, the upper surface of the element substrate and the lower surface of the phosphor plate are bonded to form the laminated body.

4. The method for manufacturing a semiconductor light emitting device according to claim 3, characterized in that: The method for manufacturing a semiconductor light emitting device further comprises a film forming step before the lamination step, in which a buffer layer is formed on at least one of an upper surface of the semiconductor light emitting layer and a lower surface of the phosphor plate. In the lamination step, the upper surface of the semiconductor light emitting layer and the lower surface of the phosphor plate are bonded via the buffer layer to form the laminated body. In the notch forming step, the notch is formed to a depth exceeding that of the buffer layer.

5. The method for manufacturing a semiconductor light emitting device according to claim 4, characterized in that: In the film forming step, the buffer layer is formed on the lower surface of the phosphor plate.

6. The method for manufacturing a semiconductor light emitting device according to claim 1, wherein: The incision forming step forms the incision by cutting with a blade, and the notch forming step forms the notch by laser scribing.

7. The method for manufacturing a semiconductor light emitting device according to claim 3, characterized in that: The element substrate is made of sapphire, and the phosphor plate is made of alumina containing phosphor particles.

8. The method for manufacturing a semiconductor light emitting device according to claim 2, wherein: The buffer layer is made of amorphous aluminum oxide.

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