Manufacturing method of semiconductor light-emitting device

Abstract

To improve manufacturing yield in a method in which a phosphor plate and a light emitting element are bonded together by surface activated bonding and the phosphor plate and the light emitting element are separated to manufacture individual semiconductor light emitting layers.SOLUTION: An upper surface of a light emitting element plate is polished. A lower surface of a phosphor plate is polished. The phosphor plate is mounted on a light emitting element, and heated and pressurized to form a laminate. From the phosphor plate side, a cut is made in the laminate at a position corresponding to a gap between multiple semiconductor light emitting layers. From the light emitting element side, a notch is formed in the laminate at the gap between the multiple semiconductor light emitting layers. The laminate is cut between the tip of the cut and the tip of the notch to separate the semiconductor light emitting devices. One of the cut and the notch is formed to have a depth exceeding a joint surface between the phosphor plate and the light emitting element plate.SELECTED DRAWING: Figure 1

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 to each other without an intermediary of a resin adhesive layer or the like. [Background technology]

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

[0003] Specifically, the manufacturing method of Patent Document 1 involves arranging pre-divided light-emitting elements on an intermediate substrate, polishing the bonding surfaces of the light-emitting elements and phosphor ceramic, and then placing the elements in a vacuum device. In the vacuum device, each bonding surface is irradiated with an ion beam of a rare gas element (at least one of He, Ne, Ar, and Kr), and the bonding surfaces are then brought into contact with each other and pressed together to bond them. After the bonded light-emitting elements and phosphor ceramic are removed from the vacuum device, the phosphor ceramic is cut into individual light-emitting devices by dicing to separate them.

[0004] On the other hand, Patent Document 2 discloses a method for manufacturing individual light-emitting devices by directly bonding a substrate of a light-emitting element and a phosphor plate by surface activation bonding, and then fracturing both the light-emitting element and the phosphor plate for each light-emitting device. In this manufacturing method, an element substrate on which a plurality of light-emitting elements are formed is bonded to a phosphor plate by surface activation bonding. Before bonding, the element substrate is thinned by grinding and polishing, and a laser beam is irradiated to a position of the thinned element substrate that will be an inter-element boundary to form a crack. The phosphor plate is brought into contact with the element substrate in which the crack is formed, and pressure is applied to bond the element substrate by surface activation bonding. Then, the phosphor plate is cut by a blade to the middle of the thickness of the phosphor plate. The position of the inter-element boundary is pressed from the light-emitting element side, and the element substrate is fractured by the crack, and at the same time, the semiconductor structure and wiring structure of the light-emitting element that were not provided with the crack, as well as the part of the phosphor plate that was not cut, are also fractured and divided into individual pieces. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-220675 A [Patent Document 2] Patent Publication No. 2021-197542 Summary of the Invention [Problem to be solved by the invention]

[0006] The manufacturing method of Patent Document 1 requires placing the light-emitting element and the phosphor ceramic in a vacuum device to irradiate an ion beam of a rare gas element onto the bonding surface of the light-emitting element and the phosphor ceramic for surface treatment. After the ion beam irradiation, the bonding surfaces of the light-emitting element and the phosphor ceramic are brought into contact and bonded in a vacuum without opening the vacuum device to the atmosphere. Therefore, all operations such as surface activation treatment, alignment, substrate heating, and substrate weighting must be performed in a vacuum, which complicates the device configuration and makes the device expensive, resulting in increased product costs.

[0007] Furthermore, the manufacturing method of Patent Document 1 involves first individualizing and arranging the light-emitting elements, then surface-activating and bonding the phosphor ceramic onto the light-emitting elements, and then cutting the phosphor ceramic into individual light-emitting devices. This creates the problem that the size of the phosphor ceramic in each individual light-emitting device is necessarily larger than that of the light-emitting elements.

[0008] On the other hand, in the manufacturing method of Patent Document 2, the light emitting elements are not singulated in advance, but cracks are introduced in advance in the element substrate by laser light so that the element substrate can be broken later, which reduces the strength of the element substrate. Therefore, when the phosphor plate is brought into contact with the element substrate and pressure is applied for surface activation bonding, it is necessary to limit the load applied in order to prevent the element substrate from cracking.

[0009] Furthermore, in a process after bonding the element substrate and the phosphor plate, the element substrate may crack due to internal stress, external stress, etc. If the element substrate is warped or an external force is applied, the element substrate and the phosphor plate may peel off from each other at the bonding surface.

[0010] Furthermore, in order to break the element substrate and phosphor plate after bonding, the phosphor plate is cut halfway through its thickness, and no cracks or notches are formed in the phosphor plate in the remaining thickness portion. Therefore, when the remaining thickness portion of the phosphor plate that has not been cut is pressed for breaking, it may break at a position that is different from the crack position of the element substrate, or the crack may spread and break in a diagonal direction relative to the crack direction of the element substrate. If the phosphor plate breaks in a position that is different from the crack position and direction of the element substrate or in a diagonal direction, it becomes a defective product with a disturbed side shape, which reduces the yield of the finished product.

[0011] An object of the present invention is to improve the manufacturing yield in a method for bonding a phosphor plate and a light-emitting element by surface activated bonding and then dividing the phosphor plate and the light-emitting element to manufacture individual semiconductor light-emitting layers. [Means for solving the problem]

[0012] In order to achieve the above object, a method for manufacturing a semiconductor light emitting device of the present invention is a method for manufacturing a semiconductor light emitting device in which a phosphor plate that absorbs light emitted from the semiconductor light emitting layer and emits fluorescence is bonded to a light emitting element including a semiconductor light emitting layer, the method comprising the steps of: a light emitting element polishing step of polishing an upper surface of a light emitting element plate including a plurality of semiconductor light emitting layers arranged with gaps in a major plane direction; a phosphor polishing step of polishing the lower surface of the phosphor plate; a lamination step of mounting a phosphor plate on the light emitting element so that an upper surface of the light emitting element plate faces a lower surface of the phosphor plate, and applying heat and pressure to form a laminate in which the phosphor plate is bonded onto the light emitting element plate; a cut-out forming step of making cuts of a predetermined depth from the phosphor plate side of the laminate at positions corresponding to the gaps between the plurality of semiconductor light-emitting layers; a notch forming step of forming notches in gaps between the plurality of semiconductor light emitting layers from the light emitting element side of the laminate; and a singulation step of cutting the laminate between the tip of the notch and the tip of the cutout to singulate the semiconductor light emitting devices.

[0013] The sum of the depth of the cut and the depth of 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 joint surface between the phosphor plate and the light-emitting element plate. Effect of the Invention

[0014] 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 then separating the phosphor plate and the light-emitting element to manufacture individual semiconductor light-emitting layers can be improved. [Brief description of the drawings]

[0015] [Figure 1] 1A and 1B are a cross-sectional view and a top view of a semiconductor light-emitting device according to a first embodiment. [Diagram 2]3(a) to 3(g) are explanatory views showing a manufacturing process of the semiconductor light emitting device according to the first embodiment. [Diagram 3] 3(a) to 3(e) are explanatory views showing a manufacturing process of the semiconductor light emitting device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the shape of the laminate after the manufacturing process of FIG. [Diagram 5] 4(a) to 4(e) are diagrams showing examples of the cross-sectional shape of a notch 110 formed in the step of FIG. 3(b) in the first embodiment. [Figure 6] 5(a) and 5(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. [Figure 7] FIG. 4 is a cross-sectional view of a semiconductor light emitting device according to a second embodiment. [Figure 8] 5(a) to 5(g) are explanatory views showing a manufacturing process of the semiconductor light emitting device according to the second embodiment. [Figure 9] 5(a) to 5(e) are explanatory views showing a manufacturing process of the semiconductor light emitting device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below.

[0017] <<First embodiment>> A method for manufacturing a semiconductor light emitting device according to the first embodiment will be described with reference to Figures 1 to 4. Figures 1(a) and (b) are a cross-sectional view and a top view of a semiconductor light emitting device 1 manufactured by the manufacturing method according to the first embodiment.

[0018] As shown in FIG. 1, in this embodiment, a phosphor plate 20 is bonded to the upper surface of a light emitting element 10 by surface activated bonding (SAB), to manufacture a semiconductor light emitting device 1. In FIG. 1, the light emitting element 10 is a flip-chip type light emitting element, and 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. The 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, the side surfaces of the light emitting element 10, the buffer layer 21, and the phosphor plate 20 are partially formed by dicing and the other partially formed by cleavage, but have a smooth shape without any sharp angles, and are covered with a light reflective multilayer film 40. The light reflective multilayer film 40 may not be provided. In addition, instead of forming the light reflective multilayer film 40, the side surfaces may be covered with a light reflective resin.

[0019] In the example of Figures 1(a) and (b), 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 are electrically connected to the pair of wirings 32.

[0020] Phosphor plate 20 absorbs a portion of the light emitted from semiconductor light emitting layer 12 and emits fluorescent light of a predetermined wavelength, thereby converting the wavelength of the light emitted from semiconductor light emitting layer 12 and emitting it from the upper surface.

[0021] The phosphor plate 20 is made 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 made of a material that transmits the light emitted by the semiconductor light emitting layer 12, for example, sapphire (Al2O3).

[0022] Surface activated bonding utilizes intermolecular forces between materials on both sides of the bonding surface, and the distance between the molecules of the materials on both sides of the bonding surface must be set to a distance at which intermolecular forces act (up to 0.5 nm or less). Therefore, in order to bond the phosphor plate 20 and the element substrate 11 by surface activated bonding, it is necessary to flatten the surfaces of the phosphor plate 20 and the element substrate 11 to a roughness equal to or less than the distance at which intermolecular forces act (up to 0.5 nm or less).

[0023] The composite ceramic phosphor plate constituting 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 differs. The hardness of the microcrystalline grains also differs depending on the direction in which the crystal axis of the microcrystals faces in phosphor plate 20. Therefore, even when phosphor plate 20 is polished, surface steps (roughness) of about 1 / 20 the particle size of the abrasive grains in the slurry used for polishing remain.

[0024] Specifically, for example, in the case of a composite ceramic phosphor plate (Al2O3 / Ce:YAG) phosphor plate 20, when mirror polished with a slurry containing 1 μm diamond particles as abrasive grains, a step of about 50 nm remains at the boundary between the crystal grains due to the difference in hardness between Al2O3 and YAG. In addition, in a YAG-based Ce:YAG phosphor plate (a plate in which Ce-doped YAG phosphor particles are dispersed in a YAG ceramic matrix), the matrix and phosphor particles are ceramics of the same chemical formula, but due to the presence of microcrystalline grains, even when polished by a CMP (chemical mechanical polishing) method with a slurry containing 50 nm diamond particles as abrasive grains, a surface step of about ±2 nm (roughness Ra ~ 1.5 nm) remains. Therefore, it is difficult to flatten the surface of the phosphor plate 20 to a roughness of less than the distance at which intermolecular forces act (~ 0.5 nm or less).

[0025] Therefore, in this 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 equal to or less than the distance (up to 0.5 nm) at which intermolecular forces act. For the CMP polishing of the buffer layer 18, a nanoslurry (diamond, silica, or alumina) having a particle size of several nm to several tens of nm is used. For example, the phosphor plate 20 is polished by a CMP (chemical mechanical polishing) method using a slurry containing diamond particles with a particle size of 50 nm as abrasive grains, and if necessary, the polished surface is further polished finely, and organic contaminants on the surface are removed, and a buffer layer 21 is formed by a vapor phase growth method after ultraviolet light (e.g., excimer light) treatment and plasma treatment are performed to activate the bonding surface (cut bonds of surface molecules and form dangling bonds). 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 the film formation, but by CMP polishing the buffer layer 21, it can be flattened to a roughness equal to or less than the distance (up to 0.5 nm) at which intermolecular forces act.

[0026] The buffer layer 21 is preferably a layer made of an amorphous dielectric material. By making the buffer layer 21 amorphous, the flatness after CMP polishing can be improved compared to when the buffer layer 21 contains microcrystals. The buffer layer 21 is preferably, for example, an amorphous Al2O3 thin film (for example, about 200 nm to 1000 nm thick) formed by EB (electron beam) deposition. The CMP polishing of the buffer layer 21 is performed using, for example, a platen equipped with a buff having a relatively low hardness and a silica-based slurry.

[0027] The buffer layer 21 is not limited to an amorphous Al2O3 thin film, and may be made of any inorganic material that is transparent to the light emitted by the semiconductor light emitting layer 12 (for example, has no light absorption over the entire white spectrum), has a thermal expansion coefficient and optical refractive index close to those of the element substrate 11 and the phosphor plate 20, has excellent thermal conductivity, good acid-alkali resistance, and low stress corrosion resistance, and can be polished to a roughness equal to or less than the distance at which intermolecular forces act (up to 0.5 nm or less).

[0028] For example, dielectric materials such as oxides containing Al (such as Al2O3), SiO2, Nb2O5, Ta2O5, TiO2, Y2O3, MgO, and ZrO2 can be suitably used as the material for the buffer layer 21.

[0029] In order to polish the buffer layer 21 to a roughness equal to or smaller than the distance at which intermolecular forces act (up to 0.5 nm or less), the buffer layer 21 is preferably amorphous, and is particularly preferably amorphous and does not contain microcrystals. If the buffer layer 21 contains microcrystals, the size of the microcrystal grains is preferably 50 nm or less, and particularly preferably 10 nm or less.

[0030] Furthermore, by using an amorphous buffer layer 21, the hardness is lower than that of a buffer layer 21 made 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 undergoes plastic deformation and can be closely fitted to the surface shape of the element substrate 11, making it easy to perform surface activated bonding.

[0031] It is preferable that the buffer layer 21 does not include any voids. If any voids are included, the surface flatness of the buffer layer 21 deteriorates, which can cause a decrease in the bonding strength of the surface activated bonding.

[0032] The method for forming the buffer layer 21 is not limited to EB deposition, and other deposition methods, such as sputtering, CVD (chemical vapor deposition), ALD (atomic layer deposition), etc., can be used. The buffer layer 21 can be an amorphous buffer layer by adjusting deposition conditions such as deposition temperature.

[0033] The thickness of the buffer layer 21 may be any thickness that can be flattened to a roughness equal to or smaller than the distance at which intermolecular forces act (up to 0.5 nm or less), and is preferably, for example, 50 nm to 2 μm, and more preferably about 200 nm to 600 nm.

[0034] The phosphor plate 20 is not limited to the composite ceramic phosphor plate (Al2O3 / Ce:YAG), but may be a phosphor plate made of a Ce:YAG single crystal, a phosphor ceramic plate with a YAG base (YAG / Ce:YAG), or glass. In the composite ceramic phosphor plate, the particle size and density of the YAG particles may be appropriately selected according to the application.

[0035] Furthermore, the light emitting element 10 may be, for example, a blue LED in which the element substrate 11 is any one of a sapphire substrate, a spinel substrate, and a GaN substrate, and the semiconductor light emitting layer 12 includes a GaN layer.

[0036] In the manufacturing process, the buffer layer 21 is preferably provided on the phosphor plate 20 side, but may be provided on both the phosphor plate 20 and the element substrate 11. Also, the buffer layer 21 may be provided only on the element substrate 11. In addition, in this embodiment, when manufacturing the semiconductor light emitting device 1, a large phosphor plate 20 in which the phosphor plates 20 of a plurality of semiconductor light emitting devices 1 are connected is bonded onto a large element substrate 11 in which a plurality of light emitting elements 10 are connected to form a laminate. Then, in order to divide the laminate at the boundary positions of the plurality of semiconductor light emitting devices 1 to form individual semiconductor light emitting devices 1, incisions are made from the phosphor plate 20 side of the laminate by dicing or the like, and notches are formed from the semiconductor light emitting layer 12 side of the element substrate 11. At this time, the incisions are formed so as to penetrate the buffer layer 21. Specifically, the incisions are formed so as to penetrate the buffer layer 21 and reach the element substrate 11. That is, the incisions are formed so as to penetrate the joint surface between the phosphor plate 20 and the light emitting element plate 100 and reach the light emitting element plate 100 (in this case, the element substrate 11). This releases the internal stress on the bonding surface between the phosphor plate 20 and the element substrate 11, and prevents stress from concentrating on the bonding surface when an external force is applied, thereby preventing the element substrate 11 and the phosphor plate from peeling off at the bonding surface. This improves the manufacturing yield. This will be described in detail in the following description of the manufacturing method.

[0037] <Manufacturing method> Figures 2 and 3 are diagrams illustrating the manufacturing steps of this manufacturing method, and Figure 4 is a cross-sectional view showing the shape of the laminate after the manufacturing step of Figure 3(c).

[0038] The manufacturing process will be described with reference to FIGS.

[0039] (Polishing process of light emitting element 10) 2(a), a light-emitting element plate 100 is prepared in which a plurality of semiconductor light-emitting layers 12 and electrodes 13 are arranged with gaps in 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 between adjacent light-emitting elements 10.

[0040] As shown in FIG. 2( a ), a support substrate 50 is bonded to the arrayed semiconductor light emitting layers 12 of the light emitting element plate 100 by a heat resistant adhesive layer 60 .

[0041] As shown in FIG. 2(b), the back surface side of the support substrate 50 (the surface opposite to the side to which the semiconductor light emitting layer 12 is adhered) is fixed to a polishing stage 80-1 by an adhesive layer 90-1.

[0042] A polishing platen 70-1 is prepared, and a slurry containing diamond abrasive grains is used to cut and polish the back surface of the element substrate 11 of the light-emitting element plate 100 to make it thinner and to flatten the surface of the element substrate 11 to a roughness (Ra) equal to or less than the distance at which intermolecular forces act (up to 0.5 nm or less).

[0043] Specifically, for example, a grinding process, a mechanical polishing process, and a CMP polishing process are carried out in this order using the polishing platen 70-1.

[0044] For example, in the grinding process, a grinding device uses a grindstone with a grain size of #230 to reduce the thickness of the element substrate 11 (for example, 830 μm) to 150 μm. The roughness (Ra) of the element substrate 11 after grinding is about 200 nm.

[0045] Next, in the mechanical polishing process, the surface of the element substrate 11 having a thickness of 150 μm after the grinding process is mechanically polished for the first time using a slurry containing diamond abrasive grains with a particle size of 6 μm, thereby reducing the roughness (Ra) of the element substrate 11 to less than 50 nm. This first mechanical polishing process can remove scratches and cracks on the surface that occurred in the grinding process. The thickness of the element substrate after this first mechanical polishing process is about 120 μm. Thereafter, a second mechanical polishing is performed 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.

[0046] Next, in the CMP polishing step, CMP polishing is performed using a slurry containing diamond abrasive grains with a grain size of 50 nm, and the roughness (Ra) of the element substrate 11 is reduced to less than 0.5 nm.

[0047] Through these steps, the surface of the element substrate 11 can be made flat to a roughness (Ra) of less than 0.5 nm, which is equal to or smaller than the distance at which intermolecular forces act (up to 0.5 nm or less).

[0048] Next, as shown in FIG. 2(c), the surface of the element substrate 11 after polishing is subjected to ultraviolet light (excimer light) treatment and plasma treatment.

[0049] Specifically, the polished surface of the element substrate 11 is irradiated with ultraviolet light (excimer light: wavelength (175±15) nm) and cleaned.

[0050] Next, the light-emitting element plate 100 is placed in a vacuum device, and plasma of one or a mixed gas of two or more of Ar, O2, and N2 is generated using high-frequency power (100 W to 450 W, preferably 250 W to 350 W), and the polished surface of the element substrate 11 is plasma-treated for a predetermined treatment time (1 min to 10 min, preferably 3 min to 6 min).

[0051] (Polishing process of phosphor plate 20) Meanwhile, as shown in FIG. 2(d), a phosphor plate 20 large enough to connect the phosphor plates 20 of a plurality of semiconductor light emitting devices 1 is prepared and fixed to a polishing stage 80-2 by an adhesive layer 90-2.

[0052] A polishing platen 70-2 is prepared, and the surface of the phosphor plate 20 is polished by the polishing platen 70-2 using a slurry containing diamond abrasive grains.

[0053] Specifically, for example, a mechanical polishing step is performed, and then a CMP polishing step is performed using the polishing platen 70-2.

[0054] In the mechanical polishing process, 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 further 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.

[0055] Next, in the CMP polishing step, CMP polishing is performed using a slurry containing diamond abrasive grains with a grain size of 50 nm, and the roughness (Ra) of the phosphor plate is reduced to less than 1 nm. Note that this CMP polishing step is performed as necessary.

[0056] Thereafter, the polishing stage 80-2 is removed from the phosphor plate 20.

[0057] (Deposition and polishing of buffer layer 21) Next, as shown in FIG. 2(e), a buffer layer 21 is formed on the polished surface of the phosphor plate 20.

[0058] For example, an amorphous Al2O3 film is formed to a thickness of 600 nm by EB deposition.

[0059] As shown in FIG. 2(f), the surface of the phosphor plate 20 opposite to the surface on which the buffer layer 21 is formed is fixed to a polishing stage 80-3 by an adhesive layer 90-3.

[0060] A polishing platen 70-3 is prepared, and a slurry containing silica particles of several nm to several tens of nm is used to polish the surface of the buffer layer 21 of the phosphor plate 20 by CMP using the polishing platen 70-3, so that the roughness (Ra) is less than 0.5 nm. This roughness (Ra) is equal to or less than the distance at which intermolecular forces act (up to 0.5 nm or less).

[0061] Next, as shown in Fig. 2(g), the polished surface of the phosphor plate 20 is subjected to ultraviolet light (excimer light) treatment and plasma treatment. The conditions for these treatments are the same as those in Fig. 2(c), and therefore a description thereof will be omitted.

[0062] It is preferable that the ultraviolet light (excimer light) treatment and plasma treatment of the element substrate 11 in FIG. 2(c) and the ultraviolet light (excimer light) treatment and plasma treatment of the phosphor plate 20 in FIG. 2(g) are completed simultaneously.

[0063] After the plasma treatment, the light emitting element 10 and the phosphor plate 20 are taken out from the vacuum device.

[0064] (Joining process) 3(a), the light-emitting element plate 100 supported by the support substrate 50 is mounted on the heating and pressing table 200, and the phosphor plate 20 is mounted thereon. At this time, the light-emitting element plate 100 is mounted so that the surface of the element substrate 11 that has been polished, treated with ultraviolet light (excimer light), and treated with plasma comes into contact with the surface of the buffer layer 21 of the phosphor plate 20 that has been polished, treated with ultraviolet light (excimer light), and treated with plasma.

[0065] 3(a) in the state shown in FIG. 3(a), the light-emitting element plate 100 and the phosphor plate 20 are heated to 100°C to 300°C, preferably 15°C to 250°C, by the heating and pressing table 200 under normal pressure, a load (e.g., 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 heated and pressed state is maintained for 30 minutes or more, preferably 2 hours or more, to bond the light-emitting element plate 100 and the phosphor plate 20 by surface activation bonding. As a result, the element substrate 11 and the phosphor plate 20 are bonded via the buffer layer 21 by surface activation bonding, and a laminate is formed.

[0066] Alternatively, the light-emitting element plate 100 and the phosphor plate 20 may be placed in a vacuum device and bonded by heating and pressurizing under reduced pressure.

[0067] (Notch formation process) As shown in FIG. 3(b), groove-shaped cuts 110 of a predetermined depth are made from the phosphor plate 20 side of the laminate at positions corresponding to the gaps between the plurality of semiconductor light emitting layers.

[0068] The cut 110 reaches the buffer layer 21 and penetrates the buffer layer 21. The cut 110 penetrates the bonding surface between the phosphor plate 20 and the light-emitting element plate 100 and reaches the element substrate 11.

[0069] Specifically, for example, the cuts 110 are formed by blade dicing using a blade with a blade width of 20 μm to 500 μm. The depth of the cuts 110 is formed so as to penetrate through the phosphor plate 20 and the buffer layer 21 and into the element substrate 11 to a depth of 1 μm to 50 μm, preferably 1 μm to 20 μm.

[0070] The cross-sectional shape of the notch 110 may be any one of a rectangle (FIG. 5(a)), a trapezoid (FIG. 5(b)), a rectangle with rounded corners (FIG. 5(c)), a trapezoid with rounded corners (FIG. 5(d)), or a parabola (FIG. 5(e)), as shown in FIGS. 5(a) to 5(e). However, a shape with rounded corners (FIGS. 5(c) to 5(e)) is preferable, and a parabola (FIG. 5(e)) is particularly preferable.

[0071] The cut 110, which has a parabolic cross section (FIG. 5(e)), has a shape in which a tip 110a of the cut cross section is closest to the lower surface (the surface on which the semiconductor light emitting layer 12 is mounted) of the element substrate 11. Therefore, in a singulation process described later, by applying force to the laminate, stress is concentrated at the tip 110a, and the element substrate 11 can be divided by cleavage or the like starting from this position.

[0072] Although the notches 110 are formed by blade dicing here, they can also be formed by laser dicing.

[0073] (Notch forming process) Next, as shown in FIG. 3(c), the support substrate 50 is removed from the semiconductor light emitting layer 12, and an adhesive sheet 120 is attached to the phosphor plate 20 side of the laminate.

[0074] A groove-shaped cutout 130 is formed in the element substrate 11 between the plurality of semiconductor light emitting layers 12 from the light emitting element plate 100 side of the laminate.

[0075] Specifically, for example, a laser scriber is used to focus laser light 170 through a lens 171 and irradiate the element substrate 11 in the gaps between the semiconductor light emitting layers 12, thereby forming groove-shaped notches .

[0076] The sum of the depth of the notch 130 and the depth of the cut 110 is set to be shallower than the thickness of the laminate. The laminate is designed to be divided by cracking such as cleavage.

[0077] Note that a protective film may be formed by a coating method on the surface of the semiconductor light emitting layer before forming the notch 130 using a laser scribing device. 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 washing with water in a later process.

[0078] It is preferable to use a nano-pulse or pico-pulse laser as the laser light 170. The wavelength of the laser light 170 may be 355 nm.

[0079] The shape of the notch 130 is preferably wedge-shaped, the width of the notch 130 is preferably 10 μm or less, and more preferably 2 μm or less, and the depth of the notch 130 is preferably 2 μm or more, and more preferably 5 μm or more.

[0080] This results in the laminate having the shape shown in FIG.

[0081] After the notch 130 is formed, the laminate is washed with water and organic cleaning to remove dirt caused by the laser scribing.

[0082] In addition, in Fig. 3(c), the laser light 170 is irradiated from the semiconductor light emitting layer 12 side, but it is also possible to irradiate the laser light 170 from the phosphor plate 20 side to form the notch 130 at the position of the notch 130 in the element substrate 11 in Fig. 3(c). For example, a stealth dicing device can be used to form a fractured surface in the element substrate 11.

[0083] Also, here, because the intervals between the semiconductor light emitting layers 12 are narrow, the notches 130 are formed by laser scribing, but it is also possible to provide the notches 130 by blade dicing using a thin blade.

[0084] (Singulation process) As shown in FIG. 3( d ), the laminate is attached to an adhesive sheet 150 with the surface of the light emitting element 10 facing downward.

[0085] When the roller 140 is pressed evenly over the entire surface of the phosphor plate 20 of the laminate, the element substrate 11 between the tip 110a of the cut 110 and the tip 130a of the cutout 130 (see FIG. 5(e)) is broken and cracked (see FIG. 5(e)). As a result, the semiconductor light emitting devices 1 are separated.

[0086] In addition, since the thermal expansion coefficient of the phosphor plate 20 is larger than that of the element substrate 11, by appropriately setting the conditions when irradiating the laser beam 170 to form the notches 130 in the step of Fig. 3(c), it is possible to cleave the element substrate 11 between the notches 130 and the cuts 110 and separate them simply by irradiating the laser beam 170 to form the notches 130. In this case, the step of applying force by the roller 140 can be omitted.

[0087] (Step of spacing the semiconductor light emitting devices 1) Finally, adhesive sheet 150 is stretched (expanded) in the direction of the main surface, widening the gap between semiconductor light emitting devices 1 on adhesive sheet 150. This makes semiconductor light emitting devices 1 ready for handling.

[0088] In this manner, the semiconductor light emitting device 1 can be manufactured (see FIG. 1).

[0089] As described above, in this embodiment, by providing a buffer layer 21 and polishing the buffer layer 21, the phosphor plate 20 can be bonded to the light emitting device by a surface activated bonding method without being affected by the crystal grains of the phosphor plate 20.

[0090] In this embodiment, the cut 110 is provided in the laminate in which the element substrate 11 and the phosphor plate of the light-emitting element plate 100 are surface-activatedly bonded to each other, to a depth that reaches the buffer layer 21, thereby preventing peeling at the bonding surface due to internal stress at the bonding surface or external force. Furthermore, in the dicing for providing the cut 110, since the substrate is hardly diced after penetrating the bonding surface (approximately 5 μm to 20 μm), a narrow dicing blade can be used. Therefore, the width of the cut 110 provided between the light-emitting elements can be made small.

[0091] Furthermore, by providing the notch 130 between adjacent semiconductor light emitting layers, the element substrate therebetween can be accurately and easily divided by cleavage or the like at the position connecting the notch 130 and the cut 110. Thus, the phosphor plate and the element substrate can be accurately divided and separated into individual semiconductor light emitting devices 1, improving the manufacturing yield.

[0092] In this embodiment, a semiconductor light-emitting device having a pair of electrodes 13 was manufactured as shown in FIG. 1, but a structure having two pairs of electrodes 13 in one semiconductor light-emitting device as shown in FIGS. 6(a) and (b) can also be manufactured by the manufacturing process described above.

[0093] <<Second embodiment>> In the second embodiment, a semiconductor light emitting device not including an element substrate 11 is manufactured as shown in Fig. 7. The manufacturing method will be described with reference to Fig. 8. In Fig. 8, the description of the manufacturing method similar to that in Figs. 2 and 3 will be omitted.

[0094] As shown in FIG. 8(a), a light emitting element plate 100 in which a semiconductor light emitting layer 12 is formed on the front surface of an element substrate 11 is prepared.

[0095] 8(b), the semiconductor light emitting layer 12 is processed into the shape of the semiconductor light emitting layer 12 for each semiconductor light emitting device by etching, etc. Then, a pair of electrodes 13 is formed on each semiconductor light emitting layer 12.

[0096] 8(c), the electrode 13 of the semiconductor light emitting layer 12 is fixed to a light-transmitting supporting substrate 301 by an adhesive layer 302 made of a resin adhesive. The supporting substrate 301 is mounted on a supporting stand 310.

[0097] As shown in Fig. 8(d), the element substrate (sapphire substrate) 11 is irradiated with laser light such as an excimer laser, and the element substrate 11 is removed by laser lift-off, thereby exposing the semiconductor light emitting layer 12 as shown in Fig. 8(e).

[0098] 8(e), the exposed semiconductor light emitting layer 12 is polished to flatten the surface, and then treated with ultraviolet light (excimer light) and plasma. The polishing, ultraviolet light (excimer light) and plasma treatment are performed in the same manner as in the steps of FIG. 2(a) to (c) of the first embodiment.

[0099] 8(f), the phosphor plate 20 is polished, a buffer layer 21 is formed on the polished surface, the surface of the buffer layer 21 is polished, and an ultraviolet light (excimer light) treatment and a plasma treatment are performed. These treatments are performed in the same manner as the steps of FIGS. 2(d) to (g) in the first embodiment.

[0100] 8(g), phosphor plate 20 is placed on semiconductor light emitting layer 12 so that buffer layer 21 is in contact with it, and heat and pressure are applied to surface activate and bond semiconductor light emitting layer 12 and phosphor plate 20. This step is performed in the same manner as the step of FIG. 3(a) in the first embodiment.

[0101] Next, in the step of FIG. 9( a ), ultraviolet light is irradiated to generate bubbles, thereby removing the support substrate 301 and adhesive layer 302 from the semiconductor light emitting layer 12 .

[0102] It should be noted that a substrate other than a light-transmitting substrate may also 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 attached by 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 support substrate 301 and the adhesive layer 302 can be removed by dissolving the sacrificial layer with nitric acid or the like.

[0103] 9(b), an adhesive sheet 350 is adhered to the electrode 13 side of the semiconductor light emitting layer 12, and a cut 341 is formed in the phosphor plate 20. This step is performed in the same manner as the step of FIG. 3(b) in the first embodiment, but differs from the first embodiment in that the depth of the cut 341 is formed so as not to reach the buffer layer 21.

[0104] 9(c), adhesive sheet 350 is removed, and adhesive sheet 360 is adhered to phosphor plate 20. A laser scriber is used to focus laser light 170 with lens 171 from the side where semiconductor light emitting layers 12 are arranged in buffer layer 21 in the gaps between the semiconductor light emitting layers 12, to form groove-shaped notches 342. This step is performed in the same manner as the step of FIG. 3(c) in the first embodiment, but differs from the first embodiment in that notches 342 are formed directly in buffer layer 21.

[0105] Thereafter, the adhesive sheet 360 is removed, and an adhesive sheet 370 is adhered to the electrode 13 side of the semiconductor light emitting layer 12. The steps of Figures 9(d) to 9(e) are carried out in the same manner as the steps of Figures 3(d) and (e) of the first embodiment to separate individual semiconductor light emitting devices.

[0106] As described above, in the second embodiment, even in the light emitting element 10 from which the element substrate 11 has been removed, the phosphor plate 20 can be bonded by surface activated bonding.

[0107] In the second embodiment, since the notch 342 is provided in the buffer layer 21, it is possible to prevent the light emitting element 10 from being subjected to stress.

[0108] Other effects of the second embodiment are similar to those of the first embodiment.

[0109] In the second embodiment, in the process of FIG. 9(c), notches 342 are formed in the buffer layer 21 in the gaps between the multiple semiconductor light emitting layers 12 from the side where the semiconductor light emitting layers 12 are arranged, but notches 342 may be formed at the tip of the cut 341.

[0110] In the second embodiment, the notch 342 is formed, but since the buffer layer 21 is a thin film, this can be arbitrarily performed as necessary. That is, the notch 342 does not have to be provided.

[0111] The technology of the semiconductor light emitting device of this embodiment can be used in a lamp light source unit or a white light source module. [Explanation of symbols]

[0112] 1. Semiconductor light-emitting device 10 Light emitting element 11 Element substrate 12 Semiconductor light-emitting layer 13 electrodes 18 Buffer layer 20 Phosphor Plate 21 Buffer layer 31 Substrate 32 Wiring 40 Light reflective multilayer film 50 Support substrate 60 Heat-resistant adhesive layer 70 Polishing Plate 80 Polishing Stage 90 Adhesive layer 100 Light emitting element plate 110a tip 120 Adhesive Sheet 130a tip 140 Roller 150 Adhesive Sheet 170 Laser Light 171 Lens 200 Pressure Table 301 Support substrate 302 Adhesive layer 310 Support stand 341 Cut 342 Notch 350 Adhesive Sheet 360 Adhesive Sheet 370 Adhesive Sheet

Claims

1. A method for manufacturing a semiconductor light emitting device in which a phosphor plate that absorbs light emitted from a semiconductor light emitting layer and emits fluorescence is bonded to a light emitting element including the semiconductor light emitting layer, the method comprising the steps of: a light emitting element polishing step of polishing an upper surface of a light emitting element plate including a plurality of semiconductor light emitting layers arranged with gaps in a major plane direction; a phosphor polishing step of polishing a lower surface of the phosphor plate; a lamination step of mounting the phosphor plate on the light emitting element such that an upper surface of the light emitting element plate faces a lower surface of the phosphor plate, and applying heat and pressure to form a laminate in which the phosphor plate is bonded onto the light emitting element plate; a cut forming step of making cuts of a predetermined depth at positions corresponding to the gaps between the plurality of semiconductor light emitting layers from the phosphor plate side of the laminate; a notch forming step of forming notches in the gaps between the plurality of semiconductor light emitting layers from the light emitting element side of the stack; a singulation step of cutting the laminate between the tip of the notch and the tip of the cutout to singulate the semiconductor light emitting device; The sum of the depth of the cut and the depth of the notch is less than a thickness of the laminate; A method for manufacturing a semiconductor light emitting device, wherein one of the cutout and the notch is formed to a depth exceeding a bonding surface between the phosphor plate and the light emitting element plate.

2. 2. A method for manufacturing a semiconductor light emitting device according to claim 1, comprising the steps of: The method further includes a film-forming step of forming a buffer layer made of an inorganic material on at least one of an upper surface of the light-emitting element plate and a lower surface of the phosphor plate before the lamination step, The lamination step includes mounting the phosphor plate on the light emitting element such that an upper surface of the light emitting element plate and a lower surface of the phosphor plate are in contact with each other via the buffer layer, and applying heat and pressure to bond the phosphor plate onto the light emitting element plate via the buffer layer, thereby forming the laminate; One of the cut and the notch is formed to a depth exceeding the buffer layer of the joint surface between the phosphor plate and the light-emitting element plate.

4. A method for manufacturing a semiconductor light emitting device comprising the steps of:

3. 2. A method for manufacturing a semiconductor light emitting device according to claim 1, comprising the steps of: the light emitting element includes an element substrate, and the light emitting element plate has a structure in which a plurality of the semiconductor light emitting layers are fixed to a lower surface of the common element substrate with the gap therebetween; the light-emitting element polishing step is a step of polishing an upper surface of the element substrate common to the light-emitting element plates, A method for manufacturing a semiconductor light emitting device, wherein the lamination step forms the laminate by bonding an upper surface of the element substrate and a lower surface of the phosphor plate.

4. 4. A method for manufacturing a semiconductor light emitting device according to claim 3, comprising the steps of: The method further includes a film formation step of forming a buffer layer on at least one of an upper surface of the semiconductor light emitting layer and a lower surface of the phosphor plate before the lamination step, The lamination step includes bonding an upper surface of the semiconductor light emitting layer and a lower surface of the phosphor plate via the buffer layer to form the laminate; A method for manufacturing a semiconductor light emitting device, wherein the notch forming step forms the notch to a depth exceeding that of the buffer layer.

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

6. 2. A method for manufacturing a semiconductor light emitting device according to claim 1, comprising the steps of: The notch forming step forms the notch by blade dicing, A method for manufacturing a semiconductor light emitting device, wherein the notch forming step forms the notch by laser scribing.

7. 4. A method for manufacturing a semiconductor light emitting device according to claim 3, comprising the steps of: the element substrate is made of sapphire; 4 is a schematic diagram showing a method for manufacturing a semiconductor light emitting device according to the first embodiment of the present invention;

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

Images