JP7343749B2 - Light emitting device and its manufacturing method - Google Patents

Description

The present invention relates to a light emitting device and a method for manufacturing the same.

A light-emitting device is used that includes a light-emitting element such as a light-emitting diode and a wavelength conversion member that is excited by light from the light-emitting element and emits light of a wavelength different from that of the light from the light-emitting element. For example, Patent Document 1 discloses a light-emitting device in which a light-emitting element and a fluorescent part, which is a wavelength conversion member, are bonded by a surface activated bonding method. It is said that such a method of manufacturing a light emitting device can be manufactured at low cost and can provide good light emitting characteristics.

Japanese Patent Application Publication No. 2012-142326

However, in recent years, the brightness of light-emitting devices has been increasing, and there is a demand for light-emitting devices with less light loss at the junction between the light-emitting element and the wavelength conversion member.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a light emitting device with less light loss at the joint between a light emitting element and a transparent member, and a method for manufacturing the same.

In order to achieve the above object, a light emitting device according to an embodiment of the present invention is a light emitting device including a light emitting element and a translucent member bonded to a light emitting surface of the light emitting element, the light emitting device comprising: a light emitting element; and the light-transmitting member is a junction comprising a part of the light-emitting element and a part of the light-transmitting member, and containing at least one rare gas element selected from the group consisting of He, Ne, Ar, and Kr. In at least one of the light-emitting element and the light-transmitting member, the distribution of the rare gas element has a peak at a position away from the light-emitting surface.

A method for manufacturing a light emitting device according to an embodiment of the present invention includes:
a light emitting element preparation step of preparing a light emitting element;
a translucent member preparation step of preparing a translucent member;
a bonding step of bonding the light emitting element and the transparent member by a surface activated bonding method;
including;
The joining step includes:
By irradiating the surface of the first bonding surface of the light emitting element to which the transparent member is bonded with an ion beam of at least one rare gas element selected from the group consisting of He, Ne, Ar, and Kr. a first surface activation step of activating;
By irradiating the surface of the second bonding surface of the light-transmitting member to which the light emitting element is bonded with an ion beam of at least one rare gas element selected from the group consisting of He, Ne, Ar, and Kr. a second surface activation step of activating;
a contacting step of bonding the light emitting element and the light-transmitting member by bringing the first bonding surface with an activated surface into contact with the second bonding surface with an activated surface;
including;
In at least one of the first surface activation step and the second surface activation step, the ion beam of the rare gas element is applied to the surface of the first bonding surface or the surface of the second bonding surface in a predetermined direction. The irradiation is performed at an angle such that the distribution density of the rare gas element at a deeper position than near the surface is higher.

According to the light emitting device of one embodiment of the present invention configured as described above, it is possible to provide a light emitting device with less loss of light at the junction between the light emitting element and the light-transmitting member.
Further, according to the method for manufacturing a light emitting device according to one embodiment of the present invention, it is possible to manufacture a light emitting device with less loss of light at the joint between the light emitting element and the transparent member.

1 is a cross-sectional view showing a specific example of a light emitting device according to an embodiment. FIG. 1A is an enlarged cross-sectional view of a part of FIG. 1A. It is a process flow diagram of the manufacturing method of the light emitting device of embodiment. It is a process flow diagram of the joining process in the manufacturing method of the light emitting device of embodiment. It is a schematic diagram of the joining process in the manufacturing method of the light emitting device of embodiment. It is a transmission electron microscope image of a cross section of a region including each part of the sapphire substrate and YAG ceramic of the example. In the TEM image of FIG. 4, this is an electron beam diffraction image of each region indicated by symbols NBD1, NBD2, NBD3, and NBD4. (a) High-angle scattering annular dark-field scanning transmission microscopy image of a cross-section of a region including a portion of the sapphire substrate and YAG ceramic of the example, (b) EDX mapping of ArK lines in the same region, (c) FIG. It is a line profile of the ArK line in the cross section shown in b).

A light-emitting device according to an embodiment of the present invention includes a light-emitting element and a light-transmitting member, and the light-transmitting member is bonded to the light-emitting surface of the light-emitting element by surface activated bonding. The optical member is bonded to the photosensitive member through the bonding region. Here, the bonding region refers to a region that is located on both sides of the light-emitting surface of the light-emitting element after bonding and consists of a part of the light-emitting element and a part of the light-transmitting member, and is defined as follows. A part of the light emitting element constituting the bonding region is a region at a predetermined depth from the light emitting surface containing a rare gas element used in ion beam irradiation for activating the light emitting surface of the light emitting element. A part of the light-transmitting member constituting the bonding region is a region at a predetermined depth from the bonding surface containing a rare gas element used in ion beam irradiation for activating the bonding surface of the light-transmitting member. Further, the rare gas element used for ion beam irradiation is at least one of He, Ne, Ar, and Kr.
In the light emitting device of the embodiment, in particular, the rare gas element used to activate the surface of a part of the light emitting element in the junction region is distributed so as to have a peak at a position away from the light emitting surface.

The light-emitting device of the embodiment configured as described above can reduce light loss at the joint between the light-emitting element and the light-transmitting member. Furthermore, the bonding strength can be increased.
On the surface irradiated with the ion beam and in its vicinity, the crystal alignment may be more disordered or distorted than in the original light-emitting element and translucent member; These phenomena can also occur due to high temperatures. In the light emitting device of the embodiment, since the peak of the distribution of the rare gas element is located at a position away from the light emitting surface, it is possible to suppress crystal disorder etc. resulting from the presence of the rare gas element at and near the light emitting surface. It is possible to maintain relatively high crystallinity. Furthermore, it is possible to arrange a region where the crystal is distorted at a position away from the light emitting surface.
That is, first, since there is no peak in the distribution of the rare gas element at the light emitting surface and the vicinity of the light emitting element and/or the light transmitting member, a part of the light emitting element and/or the light transmitting member at the light emitting surface and the vicinity thereof. In some cases, the crystal orientation is considered to be relatively difficult to disturb. From this, it is possible to reduce the loss of light in the bonding region between the light emitting element and the light-transmitting member. In other words, if the crystal orientation near the bonding interface is disordered, such as when the area is amorphous, light is likely to be scattered, but light scattering can be suppressed by making the crystal orientation in the bonding area relatively uniform. can. When scattering is suppressed, light absorption resulting from multiple scattering is suppressed, so that light extraction efficiency can be improved.

Further, in the light emitting device of the embodiment, the rare gas element is distributed so as to have a peak at a position away from the light emitting surface, and the crystal can be distorted by the inclusion of the rare gas element. Thereby, high bonding strength can be maintained even when stress due to thermal deformation is repeatedly applied to the bonded portion due to heat generation of the element or changes in environmental temperature.
In other words, if a region in which the crystal alignment is disordered is concentrated only in the very vicinity of the bonding interface (emitting surface) (for example, a region with a thickness of about ±2 nm from the bonding interface), external force or thermal stress may be applied to this thin layer. It is thought that it will be concentrated in the area. On the other hand, if the rare gas element is distributed so as to have a peak at a position away from the light emitting surface as in the light emitting device of the embodiment, the peak will be caused by the inclusion of the rare gas element at a position away from the light emitting surface. It is possible to form a region where the crystal is distorted. This allows stress to be dispersed not only in the immediate vicinity of the bonding interface (light-emitting surface) but also in the strained region. Therefore, it is possible to improve the bonding strength.
In the light emitting device of the above embodiment, the light-transmitting member can be made of, for example, sapphire, GaN, or the like. Since the surface of a light-transmitting member made of these materials is easily smoothed, surface-activated bonding can be performed more easily. In addition, if the light-transmitting member is made of the same material as the material that constitutes the bonding surface on the light-emitting element side, interface reflection due to the difference in refractive index can be substantially eliminated, so light extraction efficiency can be further improved. . Moreover, if the constituent elements of the bonding region are the same on the light-transmitting member side and the light emitting element side, the bonding strength between the two can be further increased.
Further, the light-transmitting member may contain a phosphor to have a wavelength conversion function, as shown in the following specific example.

Hereinafter, a light emitting device according to an embodiment and a method for manufacturing the same will be described using more specific examples with reference to the drawings.

FIG. 1A is a sectional view showing a specific example of a light emitting device according to an embodiment.
FIG. 1B is an enlarged cross-sectional view showing section A in FIG. 1A.
In the light emitting device of the embodiment shown in FIG. 1A, the light emitting element 10 includes, for example, a substrate 11, a semiconductor stack 12 having an n-side semiconductor layer 12a, an active layer 12b, and a p-side semiconductor layer 12c, and an n-side semiconductor layer 12. 12a, and a p-electrode 14 connected to the p-side semiconductor layer 12c. The n-electrode 13 is formed on the exposed surface of the n-side semiconductor layer 12a by removing part of the p-side semiconductor layer 12c and the active layer 12b to expose the n-side semiconductor layer 12a. The p-electrode 14 includes a diffusion electrode 14a for current diffusion formed on almost the entire surface of the p-side semiconductor layer 12c, and a p-pad electrode 14b formed on the diffusion electrode 14a.

In the light emitting device according to this embodiment, various known light emitting elements can be used as the light emitting element 10. In a light emitting element configured using a nitride semiconductor, for example, sapphire, GaN, etc. can be used as the substrate 11. The n-side semiconductor layer 12a, the active layer 12b, and the p-side semiconductor layer 12c may be formed by selecting various nitride semiconductors from binary GaN, ternary GaInN, AlGaN, quaternary AlInGaN, etc. depending on the application. I can do it.

In the light emitting device of this specific example, the light-transmitting member 20 is a wavelength conversion member made of or containing a phosphor.
The translucent member 20 of this specific example is a wavelength conversion member that is excited by the light of the light emitting element 10 (hereinafter referred to as first light) and emits light of a different wavelength from the first light, For example, it can be constructed of a polycrystal or single crystal of a phosphor, a composite of a phosphor and a binder, or a sintered body formed by molding and firing a phosphor powder and a binder powder. As the binder, for example, aluminum oxide, aluminum nitride, YAG (does not emit light because it does not contain an activator), yttrium oxide, etc. can be used.

As the phosphor, phosphors made of various materials can be used. For example, when a YAG (yttrium aluminum garnet)-based phosphor or a TAG (terbium aluminum garnet)-based phosphor is used as the phosphor, white light emission becomes possible when combined with the blue light emitting element 10. . As the light emitting element 10 that emits blue light, for example, a nitride semiconductor light emitting element containing a nitride semiconductor can be used.

When a composite of a phosphor and a binder, for example a sintered body of a phosphor and a binder, is used as the light-transmitting member 20, it is preferable that the base material of the phosphor and the binder are the same material. Thereby, the difference in refractive index between the phosphor and the binder can be substantially eliminated, and the reflection of light at the interface between the binder and the phosphor can be reduced. For example, it is possible to use YAG (does not emit light because it does not contain an activator) as a binder, and use a so-called YAG-based phosphor having cerium as an activator and YAG as a matrix as a phosphor. Further, the wavelength conversion member may include a scattering material. For example, YAG ceramic can be used as the wavelength-convertible light-transmitting member 20. Examples of the YAG ceramic include a sintered body obtained by sintering a YAG phosphor and a binder, or a sintered body obtained by sintering a YAG phosphor without using a binder.

In the light-emitting device shown in FIG. 1A, the light-emitting surface of the light-emitting element 10 (the surface opposite to the surface of the substrate 11 on which the semiconductor laminated portion 12 is formed) and the light-transmitting member 20 are bonded via the bonding region 30. ing. As shown in FIG. 1B, the bonding region 30 includes a first bonding region 11a that is a part of the light emitting element 10 (substrate 11) and a second bonding region 20a that is a part of the translucent member 20. As described above, each of the first bonding region 11a and the second bonding region 20a is a region containing a rare gas element used when the surfaces to be bonded are activated by ion beam irradiation. In addition, the crystal structure of the first bonding region 11a can be confirmed and the crystallinity is maintained, and the rare gas element used for activation has a peak at a position away from the bonding interface (light emitting surface). It is distributed to have. Note that whether or not the crystal structure is maintained, that is, whether it is not amorphous or not, can be determined by, for example, whether or not diffraction spots are observed in a diffraction experiment. Note that in this embodiment, YAG ceramic is used as the light-transmitting member 20, and the light-transmitting member 20 as a whole is not a single crystal. In this case, the region where the crystal arrangement is disordered by the ion beam irradiation of the light-transmitting member 20 refers to the region where the contrast has changed when cross-sectionally observed using a TEM (transmission electron microscope image). In this way, when a cross-sectional observation using TEM shows that the contrast differs between the bonding interface and its vicinity and the outside, it is thought that the crystal is distorted at the bonding interface and its vicinity. It is called.

When sapphire is used as the substrate 11, the first bonding region 11a is formed, for example, in a portion of the substrate 11 with a thickness of 10 nm to 40 nm from the light emitting surface (bonding interface) of the light emitting element 10. The bonding region may have a portion that does not substantially contain the rare gas element near the bonding interface. For example, the distribution of the rare gas element in the first bonding region 11a can be minimized at or near the bonding interface, and maximized at a position further away from the bonding interface. The content of the rare gas element in the strained layer is preferably lower than the content in the peak portion throughout the strained layer. It is thought that this makes it possible to suppress irregularities in the atomic arrangement of the strained layer.
When YAG ceramic is used as the light-transmitting member 20, the second bonding region 20a is formed, for example, in a portion of the light-transmitting member 20 with a thickness of 5 nm to 20 nm from the light emitting surface (bonding interface) of the light emitting element 10. Ru. The peak of the distribution of the rare gas element in the second bonding region 20a may be located at a position that substantially coincides with the bonding interface. A position that substantially coincides with the bonding interface refers to a position where the distance from the bonding interface is 2 nm or less. The bonding interface can be identified using a TEM image or a combination of this and EDX analysis (energy dispersive X-ray analysis). If the boundary between the substrate 11 and the light-transmitting member 20 is ambiguous and difficult to clearly identify, the position of the peak can be determined by the presence of a peak in the distribution of rare gas elements within the region presumed to be the bonding interface. may almost coincide with the bonding interface. The range in which the first bonding region 11a and the second bonding region 20a are formed can be adjusted depending on the conditions of ion beam irradiation. Therefore, by appropriately setting the ion beam irradiation conditions in consideration of the material of the substrate 11, the material of the translucent member 20, the required bonding strength, and the amount of light absorption, the thickness of the bonding region 30 and the rare gas The distribution of elements can be optimized.

In the specific example described above with reference to FIG. 1, the light emitting element 10 including the substrate 11 is used, and the substrate 11 and the light-transmitting member 20 are directly bonded. However, in the light emitting device of this embodiment, the semiconductor laminated portion 12 of the light emitting element 10 including the substrate 11 and the transparent member 20 may be directly bonded, or the light emitting element 10 not including the substrate 11 may be directly bonded. The semiconductor laminated portion 12 may be directly bonded to the light-transmitting member 20 by using the semiconductor laminated portion 12. That is, the semiconductor laminated portion 12 and the light-transmitting member 20 can be bonded regardless of the presence or absence of the substrate. When the semiconductor laminated portion 12 and the light-transmitting member 20 are bonded, a portion of the light-transmitting member 20 and a portion of the outermost semiconductor layer of the semiconductor laminated portion 12 constitute a bonding region. Furthermore, after forming the semiconductor laminated part 12 on the substrate 11 as the light emitting element 10, a bonded substrate such as Si is bonded on the semiconductor laminated part 12, and then the original substrate is removed and the bonded substrate is It is also possible to join the transparent member 20.

Next, a method for manufacturing the light emitting device of the embodiment will be described.

As shown in FIG. 2A, the method for manufacturing a light emitting device of the embodiment includes a light emitting element preparation step, a wavelength conversion member preparation step, a bonding step, and a singulation step. Further, the bonding process includes a surface activation step and a bonding step, as shown in FIG. 2B. Each step will be explained in detail below.

1. Light-emitting element preparation process In the light-emitting element preparation process, a light-emitting element is prepared. In the light emitting element preparation step, the surface to which the light-transmitting member is bonded is polished to a smooth surface with a surface roughness (Ra) of, for example, 10 nm or less, preferably 5 nm or less, more preferably 1 nm or less. It is preferable. Thereby, the light emitting element 10 and the light-transmitting member 20 can be easily and firmly joined.

For example, when preparing the light emitting element 10 shown in FIG. 1A, the following steps are performed.
First, a wafer in which a plurality of substrates 11 are integrated after being singulated is prepared. When preparing a nitride semiconductor light emitting device, the wafer to be prepared is, for example, a sapphire wafer.
Next, an n-side semiconductor layer 12a, an active layer 12b, and a p-side semiconductor layer 12c, which constitute the semiconductor laminated portion 12, are grown on the upper surface of the wafer. The n-side semiconductor layer includes an n-side semiconductor. Further, the p-side semiconductor layer includes a p-side semiconductor.
Next, in regions corresponding to the individual light emitting elements 10, parts of the p-side semiconductor layer 12c and the active layer 12b are removed to expose the n-side semiconductor layer 12a.
Then, an n-electrode 13 is formed on each exposed surface of the n-side semiconductor layer 12a.
Further, a p-electrode 14 is formed on the surface of the p-side semiconductor layer 12c in each region.
The p electrode 14 includes a diffusion electrode 14a for current diffusion formed on almost the entire surface of the p-side semiconductor layer 12c in each region, and a p pad electrode 14b formed on a part of the diffusion electrode.

Next, the lower surface of the wafer is smoothed by, for example, mechanical polishing or chemical mechanical polishing (CMP) to have a surface roughness (Ra) of, for example, 10 nm or less, preferably 5 nm or less, more preferably 1 nm or less. Polish it so that it has a smooth surface. For example, the method may include a step of adjusting the thickness of the wafer to a desired thickness before chemical-mechanically polishing the lower surface of the wafer.
When polishing a member made of multiple materials, it may be preferable to use mechanical polishing instead of CMP. For example, if the YAG ceramic contains a diffusion material, the difference between the etching rate of the diffusion material and the etching rate of the YAG phosphor tends to become large. For this reason, it is preferable to planarize by mechanical polishing. This makes it possible to obtain a smoother surface compared to CMP.
After polishing, it is divided into individual light emitting elements 10.
In the manner described above, the light emitting element 10 is prepared by polishing the bonding surface (light emitting surface) of the substrate 11 so that it becomes smooth.

2. Transparent Member Preparation Step In the translucent member preparation step, a translucent member plate into which the translucent member 20 is integrated is prepared. In the light-transmitting member preparation step, the surface of the light-transmitting member plate to which the light emitting element is bonded is a smooth surface with a surface roughness (Ra) of, for example, 10 nm or less, preferably 5 nm or less, more preferably 1 nm or less. It is preferable to polish it so that it becomes . Thereby, the light emitting element 10 and the light-transmitting member 20 can be easily and firmly joined.
For example, when preparing the translucent member 20 made of sapphire (support) containing YAG (phosphor), as illustrated with reference to FIG. A light-transmitting member plate in which a plurality of light-transmitting members 20 are integrated is produced. The light-transmitting member preparation step may include a step of grinding and polishing the light-transmitting member plate to a desired thickness so that light with a desired chromaticity is emitted from the light-emitting device. . In the translucent member preparation step, the translucent member plate may be separated into a plurality of translucent members. Note that the order of the light emitting element preparation step and the translucent member preparation step may be reversed.

3. Bonding process In the bonding process, the surfaces of the bonding surface of the light emitting element and the bonding surface of the translucent member are activated by irradiating them with an ion beam of a rare gas element (surface activation step). The surfaces to be joined are brought into contact and joined (contact step).
In this bonding step, in particular, in the surface activation step, an ion beam of a rare gas element is applied to at least one of the surface of the bonding surface of the light-emitting element and the surface of the bonding surface of the light-transmitting member, as will be described in detail later. The irradiation is performed at a predetermined angle so that the distribution density of the rare gas element at a deeper position is higher than near the surface.

(Surface activation step)
First, as shown in FIG. 3A, a plurality of light emitting elements 10 are arranged on a relay board 40 that includes a substrate and a silicone resin 42 coated on the substrate 41 and cured. At this time, the light emitting element 10 is held by the tackiness of the silicone resin 42. The light emitting element 10 is held on the relay board 40 on the opposite side to the light emitting surface (bonding surface) of the light emitting element 10 . For example, in the light emitting element 10 shown in FIG. 1A, the surface on which the p electrode 14 and the n electrode 13 are formed is held on the relay substrate 40.

Next, as shown in FIG. 3(B), the plurality of light emitting elements 10 arranged on the relay board 40 and the light-transmitting member plate 21 are arranged to face each other inside the bonding chamber. For example, the relay board 40 on which the light-emitting elements 10 are arranged is placed in the upper part of the bonding chamber with the light-emitting surface of each light-emitting element 10 facing downward, and the light-transmitting member plate 21 is placed with the bonding surface of the light-transmitting member plate 21 facing upward. 21 is placed at the bottom of the bonding chamber. After the light emitting element 10 and the transparent member plate 21 are placed in the bonding chamber, the inside of the bonding chamber is evacuated to a pressure of, for example, 1×10 ⁻⁵ Pa or less, preferably 5×10 ⁻⁶ Pa or less.

Inside the bonding chamber, there is a tube in the center (a position sandwiched between the relay board 40 on which a plurality of light emitting elements are arranged and the transparent member plate 21) that irradiates the light emitting surface of the light emitting element 10 with an ion beam. A first high-speed ion beam gun 51 and a second high-speed ion beam gun 52 that irradiates an ion beam onto the joint surface of the transparent member plate are provided. Between the first fast ion beam gun 51 and the second fast ion beam gun 52, there is a Preferably, a light shielding plate is provided so that the light emitting element is not irradiated with the ion beam irradiated from the high speed ion beam gun 52.

Further, the first high-speed ion beam gun 51 and the second high-speed ion beam gun 52 are configured so that they can respectively irradiate the light-emitting surface of the light-emitting element 10 and the joint surface of the transparent member plate 21 with ion beams at predetermined angles. It is preferable that the configuration is such that the irradiation direction can be adjusted. This allows the rare gas element to penetrate to a desired depth. Furthermore, the first high-speed ion beam gun 51 and the second high-speed ion beam gun 52 are configured such that the ion beam is irradiated at a constant irradiation angle to the light-emitting surface of the light-emitting element 10 and the joint surface of the transparent member plate 21, respectively. (first surface activation step and second surface activation step). However, either the first surface activation step or the second surface activation step may be performed first, or they may be performed simultaneously. When the ion beam is irradiated at a constant irradiation angle to the light-emitting surface of the light-emitting element and/or the joint surface of the translucent member plate, the rare gas element used for ion beam irradiation is transferred from the joint surface (light-emitting surface). It becomes possible to stably distribute the particles at a desired depth and at a high density. In other words, the inventors have confirmed that the depth at which the rare gas element penetrates during ion beam irradiation changes depending on the ion beam irradiation angle with respect to the crystal plane of the bonding surface (light-emitting surface). There is. Therefore, when the irradiation angle of the ion beam with respect to the bonding surface (light-emitting surface) changes, the depth at which the rare gas element penetrates changes, making it difficult to stably distribute the rare gas element at a desired depth. For example, when irradiating sapphire with an ion beam, the angle of incidence of the ion beam is preferably in the range of 40 degrees to 50 degrees with respect to the C-plane of the sapphire, and more preferably about 45 degrees ± 1 degree. The incident angle of the ion beam refers to the angle formed by the normal line of the ion irradiation port and the normal line of the bonding surface. For example, in the case of the first high-speed ion beam gun 51 shown in FIG. 3B, the ion irradiation port is the surface facing the bonding surface of the light emitting element 10.

In consideration of the above, in the method for manufacturing a light emitting device of this embodiment, the ion beams from the first high speed ion beam gun 51 and the second high speed ion beam gun 52 are limited to a narrow irradiation range and irradiated at a predetermined irradiation angle. It is preferable to irradiate the entire joint surface by scanning the entire irradiation range. By scanning, the spread of the ion beam can be made smaller than in the case of no scanning, so that the deviation from the irradiation angle of the ion beam can be made smaller. That is, in the surface activation step, an ion beam of a rare gas element is applied to the surface of the first bonding surface or the surface of the second bonding surface in at least one of the first surface activation step and the second surface activation step. It is possible to irradiate while scanning at a predetermined angle.

(contact step)
As shown in FIG. 3(C), the light-emitting surface (first bonding surface) of the light-emitting element whose surface has been activated and the bonding surface (second bonding surface) of the light-transmitting member plate whose surface has been activated are connected. By bringing them into contact, the light emitting element and the light-transmitting member plate are joined. At this time, no adhesive is present between the light emitting element and the transparent member plate. Pressure may be applied during contact. Since the silicone resin that temporarily holds the light emitting element is soft, by applying pressure during bonding, even if the thickness of the light emitting element varies, it is possible to bond the light emitting element with better adhesion. At this time, it is preferable to perform temporary bonding in which preliminary bonding is performed at a relatively low pressure, and then to perform bonding (main bonding) with a pressure higher than the temporary bonding. The pressurizing step may not be performed.

4. Singulation Step In the singulation step, the light-transmitting member plate is taken out from the bonding chamber and cut into pieces into individual light-emitting devices as described below, for example.
First, a bonded body in which a plurality of light emitting elements are bonded onto a light-transmitting member plate is taken out from the bonding chamber, and the relay board is removed from the bonded body.
Next, the light-transmitting member plate is separated into individual light-emitting devices by, for example, dicing so as to contain at least one light-emitting element.
After singulation, the light-emitting device is mounted, for example, by flip-chip on a substrate on which wiring electrodes are formed, and the upper surface of the light-transmitting member, which becomes the light-emitting surface of the light-emitting device, is removed, and titania particles are dispersed in, for example, silicone resin. It may also be covered with white resin.

In the manner described above, the light emitting device of the embodiment can be manufactured.
That is, according to the method for manufacturing a light emitting device of the embodiment described above, the light emitting element and the light transmitting material are bonded to each other through the bonding region in which the rare gas element is distributed such that the peak is located away from the bonding interface (light emitting surface). A light emitting device in which members are directly joined can be manufactured.

Example In this example, first, a light emitting element in which a semiconductor laminated portion was formed on a sapphire substrate and a YAG ceramic containing a YAG phosphor as a light-transmitting member were prepared.
The bonding surface of the sapphire substrate and the bonding surface of the YAG ceramic were each polished to a surface roughness Ra of 1 nm.

Next, the light emitting element and the YAG ceramic were set in a bonding chamber so that their bonding surfaces faced each other, and the chamber was evacuated to an ultimate vacuum of 2×10 ⁻⁶ Pa.
Then, Ar ion beams were applied to the surface (joint surface) of the sapphire substrate, which is the light emitting surface of the light emitting element, and the surface (joint surface) of the YAG ceramic at a predetermined angle to activate each surface. In this example, the surface of the sapphire which is the light emitting surface, that is, the bonding surface is a C-plane, and the Ar ion beam was irradiated so that the angle between the C-plane and the ion irradiation port of the ion beam source was 45 degrees. Further, the flow rate of the Ar ion beam was 20 sccm (corresponding to an accelerating voltage of about 1 keV), and the accelerating current was 100 mA. The ion beam was narrowed down to a size narrower than the surface of the YAG ceramic, and the ion beam was irradiated to each joint surface while scanning the ion beam so that the irradiation angle was constant. The ion beam was irradiated while scanning repeatedly. The ion beam irradiation time was approximately 300 seconds due to this repeated scanning of the ion beam irradiation.

Next, the activated sapphire surface (joint surface) and the YAG ceramic surface (joint surface) were temporarily joined and then finally joined.

Crystallinity and Ar distribution were evaluated based on the bonded region of the sapphire and YAG ceramic bonded as described above and the cross sections of the sapphire and YAG ceramic on both sides thereof.
FIG. 4 shows a high-resolution TEM image of a cross section of a region including the bonding region and portions of sapphire and YAG ceramic on both sides thereof. FIG. 5 shows an electron beam diffraction image of each region indicated by symbols NBD1, NBD2, NBD3, and NBD4 in the cross-sectional image of FIG. 4.
In FIG. 5, (a) is an electron beam diffraction image of the sapphire single crystal of NBD1. (b) is an electron beam diffraction image of NBD2 that forms part of the bonding region on the sapphire side. (c) is an electron beam diffraction image of NBD3 forming part of the bonding region on the YAG ceramic side. (d) It is an electron beam diffraction image of YAG ceramic of NBD4. As shown in FIG. 5, diffraction spots are observed in all regions, indicating that crystallinity is maintained. The diffraction image in FIG. 5(c) is similar to FIGS. 5(a) and (b) because of the possibility that sapphire exists in the NBD3 region and the size of the electron beam in the NBD3 region shown in the diagram. It is possible that information from the sapphire side was also reflected. Further, in FIG. 4, in both the sapphire and YAG ceramics, the contrast at a depth of about several nanometers from the bonding interface was different from that at a deeper region. From this, the portion from the bonding interface to a depth of about several nm is the above-mentioned strained layer. Such strained layers were arranged in layers along the bonding interface.

In FIG. 6, (a) is a cross-sectional view of the bonding region and the region including the sapphire substrate and a portion of the YAG ceramic on both sides thereof, observed with a high-angle scattering annular dark-field scanning transmission microscope. The upper black area in FIG. 6(a) represents sapphire and the lower white area represents YAG ceramic. (b) is an intensity map showing the distribution of Ar K-line by EDX in the same area as in FIG. 6(a). (c) is a line profile in the vertical direction in the figure (b), and the vertical axis represents the distance from the top of the image in (b). That is, a position approximately 50 nm deep from the light emitting surface (junction surface) inside the sapphire is shown as the origin. The part at a distance of 50 nm from the origin is the light emitting surface, that is, the bonding interface, the part at a distance of about 50 nm or less is the sapphire side, and the part at a distance of about 50 nm or more is the YAG ceramic side.
Background intensity is observed in a region up to a distance of 15 nm from the origin on the sapphire side, and it can be considered that Ar is not substantially included in this region. That is, in this example, the first bonding region on the sapphire side constituting the bonding region is a region with a distance of 15 nm to 50 nm from the origin, and a depth of about 35 nm from the bonding interface. Note that in the region at a distance of about 45 nm to 50 nm from the origin, that is, the region from the bonding interface to a depth of about 5 nm, the count number is almost the same as in the region at a distance of 15 nm from the origin, so Ar is substantially included. It is considered that the Ar content is low, or is close to it. In this way, the distribution of Ar content in the first bonding region on the sapphire side is minimal at and near the bonding interface, and maximal at a position further away from the bonding interface.

In this example, the second bonding region on the YAG ceramic side constituting the bonding region is a region at a distance of 50 nm to 60 nm from the origin and a depth of up to 10 nm from the bonding interface. A portion on the transparent member side at a distance of 60 nm or more from the origin is a background region that does not contain Ar. The difference in the background counts between the sapphire side and the YAG ceramic side is due to the difference in materials.

As shown in FIG. 6 above, it can be seen that the Ar distribution on the sapphire side has a peak at a position away from the bonding interface.
In addition, when the Ar ion beam is incident perpendicularly to the sapphire surface, and assuming that the acceleration voltage of the ion beam is approximately 1 keV, calculations show that the depth at which Ar ions can penetrate into the sapphire is approximately 5 nm. . In the case of oblique incidence, the depth that can be penetrated further should be shorter. However, from FIG. 6C, it was confirmed that although Ar ions were obliquely incident, Ar was implanted even deeper. This is considered to be due to the occurrence of a channeling phenomenon. In other words, it is presumed that this is because ions pass through the sapphire crystal lattice, reducing the number of scattered ions.
Furthermore, the distribution of Ar on the YAG ceramic side had a peak within a region presumed to be the bonding interface, that is, it had a peak at a position that almost coincided with the bonding interface.

10 Light emitting element 11 Substrate 11a First bonding region 12a N-side semiconductor layer 12b Active layer 12c P-side semiconductor layer 12 Semiconductor laminated portion 13 N-electrode 14 P-electrode 14a Diffusion electrode 14b P-pad electrode 20 Transparent member 20a Second bonding region 21 Transparent member plate 30 Bonding area 40 Relay board 41 Substrate 42 Silicone resin 51 First high speed ion beam gun 52 Second high speed ion beam gun

Claims (18)

A light-emitting device including a light-emitting element and a light-transmitting member bonded to a light-emitting surface of the light-emitting element,
The light-emitting element and the light-transmitting member include a part of the light-emitting element and a part of the light-transmitting member, and include at least one rare gas element selected from the group consisting of He, Ne, Ar, and Kr. are joined through a joining area containing
In at least one of the light-emitting element and the light-transmitting member, the distribution of the rare gas element has a peak at a position away from the light-emitting surface. The light-emitting device according to claim 1, wherein the bonding region includes strained layers on the light-emitting element side and the transparent member side, respectively. 3. The light emitting device according to claim 1, wherein the light emitting element includes a substrate and a semiconductor laminated portion laminated on the substrate, and a bonding region on the side of the light emitting element is a part of the substrate. The light emitting device according to claim 3, wherein the substrate is made of sapphire. The light emitting device according to claim 1, wherein the light-transmitting member includes a phosphor. The light emitting device according to claim 1, wherein the light-transmitting member is a YAG ceramic. 7. The light emitting device according to claim 1, wherein the rare gas element is Ar. a light emitting element preparation step of preparing a light emitting element;
a translucent member preparation step of preparing a translucent member;
a bonding step of bonding the light emitting element and the transparent member by a surface activated bonding method;
including;
The joining step includes:
By irradiating the surface of the first bonding surface of the light emitting element to which the transparent member is bonded with an ion beam of at least one rare gas element selected from the group consisting of He, Ne, Ar, and Kr. a first surface activation step of activating;
By irradiating the surface of the second bonding surface of the light-transmitting member to which the light emitting element is bonded with an ion beam of at least one rare gas element selected from the group consisting of He, Ne, Ar, and Kr. a second surface activation step of activating;
a contacting step of bonding the light emitting element and the light-transmitting member by bringing the first bonding surface with an activated surface into contact with the second bonding surface with an activated surface;
including;
In at least one of the first surface activation step and the second surface activation step, the ion beam of the rare gas element is applied to the surface of the first bonding surface or the surface of the second bonding surface in a predetermined direction. A method for manufacturing a light emitting device, characterized in that irradiation is performed at an angle such that the distribution density of the rare gas element at a deeper position than near the surface is higher. In the first surface activation step, the ion beam of the rare gas element is irradiated at a predetermined angle to the surface of the first bonding surface, so that the distribution density of the rare gas element at a deeper position than near the surface is increased. 9. The method for manufacturing a light emitting device according to claim 8, wherein the irradiation is performed so that 10. The method of manufacturing a light emitting device according to claim 8, wherein the light emitting element includes a substrate and a semiconductor laminated portion laminated on the substrate, and the first bonding surface is a surface of the substrate. 11. The method of manufacturing a light emitting device according to claim 10, wherein the substrate is made of sapphire. The method for manufacturing a light emitting device according to claim 8, wherein the rare gas element is Ar. In at least one of the first surface activation step and the second surface activation step, the ion beam of the rare gas element is applied to the surface of the first bonding surface or the surface of the second bonding surface. The method for manufacturing a light emitting device according to any one of claims 8 to 12, characterized in that the irradiation is performed while scanning at a predetermined angle. the substrate is sapphire;
The light-transmitting member is YAG ceramic,
The bonding area includes a first bonding area that is part of the substrate and a second bonding area that is part of the light-transmitting member,
The first bonding region is 10 nm or more and 40 nm or less from the bonding interface,
The light emitting device according to claim 3 or claim 7, which refers to claim 3 , wherein the second bonding region is 5 nm or more and 20 nm or less from the bonding interface. 15. The light emitting device according to claim 14, wherein the first junction region has a crystal structure that can be confirmed. Claim 11, Claim 12 citing Claim 11, and Claim 11 citing Claim 11, wherein the predetermined angle is an incident angle of the ion beam with respect to the C-plane of the sapphire from 40 degrees to 50 degrees. The method for manufacturing a light emitting device according to claim 13. The light-transmitting member is YAG ceramic,
17. The method for manufacturing a light emitting device according to claim 8 , wherein the size of the ion beam is narrowed to be narrower than the surface of the YAG ceramic. In the first surface activation step, the ion beam is irradiated by a first high-speed ion beam gun,
In the second surface activation step, the ion beam is irradiated by a second high-speed ion beam gun,
The method for manufacturing a light emitting device according to any one of claims 8 to 13, 16, and 17, wherein a light-shielding plate is provided between the first high-speed ion beam gun and the second high-speed ion beam gun.

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