Ultraviolet light-emitting element

Abstract

To provide a light-emitting device having high luminous efficiency and a long service life.SOLUTION: An ultraviolet light-emitting element includes: a semiconductor chip; a circuit board arranged facing the semiconductor chip; and a plurality of connectors that connect the semiconductor chip and the circuit board. The ultraviolet light-emitting element has a first conductivity-type electrode and a second conductivity-type electrode on a surface of the semiconductor chip facing the circuit board. The first conductivity-type electrode has a first conductivity-type electrode linear part in contact with the connector. The second conductivity-type electrode comes in contact with the connector and has a second conductivity-type electrode linear part extending in a vertical direction with respect to the first conductivity-type electrode linear part. Some of the plurality of connectors are connectors on the plurality of second conductivity-type electrode linear parts arranged in contact with the second conductivity-type electrode linear part, and an area of each of the connectors on the plurality of second conductivity-type electrode linear parts in contact with the semiconductor chip is increased toward the first conductivity-type electrode linear part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an ultraviolet light emitting device.

Background Art

[0002] An ultraviolet light emitting device can control the emission wavelength from deep ultraviolet to infrared by controlling the composition of a semiconductor active layer which is a light emitting layer, and is used in various applications such as a backlight for illumination, a light source for a measuring instrument, and a sterilization light source. In a general form of an ultraviolet light emitting device, a semiconductor chip that emits ultraviolet light is mounted on a circuit board (package substrate) that is disposed opposite via a metal connector. In an ultraviolet light emitting device having a flip chip structure which is one of this form, a p-type electrode and an n-type electrode are formed on one surface of the semiconductor chip, this surface is opposed to the package substrate, and the semiconductor chip and the package substrate are connected by a connector such as a metal ball, so that light is emitted from the other surface of the semiconductor chip.

[0003] The p-type electrode and the n-type electrode of the semiconductor chip are electrically joined to corresponding positive electrode metal wires and negative electrode metal wires on the package substrate respectively, and play a role of flowing current to the semiconductor chip by applying a voltage from the outside. In addition, a connector such as a metal ball also exhibits a heat dissipation effect of releasing heat generated in the semiconductor chip to the package substrate.

[0004] For the purpose of improving the light emission efficiency and the power conversion efficiency of the ultraviolet light emitting device, the n-type electrode and the p-type electrode of the semiconductor chip are arranged in a shape such that they are alternately arranged (Patent Document 1). In this case, the connectors connecting the n-type electrode of the semiconductor chip and the n-type electrode of the circuit board, or the p-type electrode of the semiconductor chip and the p-type electrode of the circuit board are designed to be in contact with the linear portions of the respective electrodes and arranged in a straight line at regular intervals. At this time, there are a plurality of connectors, and each connector is designed to have the same shape and connect to the semiconductor chip and the circuit board.

[0005] In yet another invention, it has been reported that the p-type electrode of a semiconductor chip has an H-shaped electrode layout combining a straight portion and a protrusion surrounded by the n-type electrode in three directions (Patent Document 2). Here, by widening the distance between the p-type electrode and the n-type electrode at the protrusion compared to the distance between the p-type electrode and the n-type electrode in the straight portion, a design is made to diffuse the current so that the current does not concentrate at the protrusion, thereby alleviating local heat generation at the protrusion.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in conventional ultraviolet light-emitting elements, the current flowing between the electrodes is partially concentrated, resulting in unevenness in the amount of emitted light. As a result, the luminous efficiency of the ultraviolet light-emitting element may decrease, or the element may have a short lifespan due to local destruction of the element. An object of the present disclosure is to obtain an ultraviolet light-emitting element with high luminous efficiency and long lifespan.

Means for Solving the Problems

[0008] In order to solve the above-described problems, an ultraviolet light-emitting device according to one aspect of the present disclosure includes a semiconductor chip, a circuit board disposed to face the semiconductor chip, and a plurality of connectors that connect the semiconductor chip and the circuit board. In the ultraviolet light-emitting device according to one aspect of the present disclosure, a first conductivity type electrode and a second conductivity type electrode are provided on a surface of the semiconductor chip facing the circuit board. The first conductivity type electrode has a first conductivity type electrode straight portion that contacts the connector. The second conductivity type electrode has a second conductivity type electrode straight portion that contacts the connector and extends in a direction intersecting the first conductivity type electrode straight portion. A part of the plurality of connectors is a plurality of second conductivity type electrode straight portion upper connectors disposed in contact with the second conductivity type electrode straight portion, and the area of contact of each of the plurality of second conductivity type electrode straight portion upper connectors with the second conductivity type electrode straight portion increases as it approaches the first conductivity type electrode straight portion.

Effects of the Invention

[0009] According to the present disclosure, it is possible to provide an element with high luminous efficiency and long life.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0011] Hereinafter, the ultraviolet light-emitting element according to the present disclosure will be described through embodiments. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention. Also, in the following description, the positive direction of the Z-axis may be referred to as "up", and the negative direction of the Z-axis may be referred to as "down". "Up" and "down" do not necessarily mean the vertical direction with respect to the ground. That is, the directions of "up" and "down" are not limited to the gravitational direction. "Up" and "down" are merely convenient expressions for specifying the relative positional relationship in a surface, film, substrate, etc., and do not limit the technical idea of the present disclosure. For example, if the paper surface is rotated 180 degrees, "up" becomes "down" and "down" becomes "up", of course.

[0012] 1. Embodiment The ultraviolet light-emitting element according to an embodiment of the present disclosure will be described. In this embodiment, the case where the first conductivity type of the ultraviolet light-emitting element is n-type and the second conductivity type is p-type will be described, but this is not the only case.

[0013] (1.1) Configuration of Ultraviolet Light-Emitting Element The ultraviolet light-emitting element 1 according to this embodiment includes a semiconductor chip 10, a circuit board 20 disposed opposite to the semiconductor chip 10, and a plurality of connectors 30 (shown as an n-type connector 31 and a p-type connector 32 in the figure) that connect the semiconductor chip 10 and the circuit board 20. In the semiconductor chip 10, an n-type electrode (an example of a first conductivity type electrode) 15 and a p-type electrode (an example of a second conductivity type electrode) are provided on the surface facing the circuit board 20. The n-type electrode 15 has an n-type electrode straight portion (an example of a first conductivity type electrode straight portion) 15A that contacts the connector 30, and the p-type electrode (an example of a second conductivity type electrode) 16 contacts the connector 30 and has p-type electrode straight portions (an example of a second conductivity type electrode straight portion) 16A to 16D disposed perpendicular to the n-type electrode straight portion 15A. Among the plurality of connectors 30 in the ultraviolet light-emitting element 1, the connectors (p-type connectors 32A to 32P in FIG. 1), which are a part of them, are a plurality of p-type connectors 32 disposed in contact with the p-type electrode straight portions 16A to 16D. Each of the plurality of p-type connectors 32 (p-type connectors 32A to 32P) disposed on the p-type electrode straight portions 16A to 16D is in contact with the semiconductor chip 10, and the area where the p-type connector 32 contacts the semiconductor chip 10 increases as it approaches the n-type electrode straight portion 15A.

[0014] The ultraviolet light-emitting element 1 according to the embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic plan view showing the arrangement positions of the n-type electrode 15 and the p-type electrode 16 when the semiconductor chip 10 constituting the ultraviolet light-emitting element 1 is viewed from above. In FIG. 1, the outer shapes of the semiconductor chip 10, the n-type electrode 15 and the p-type electrode 16 of the semiconductor chip 10, and the connector 30 are shown. FIG. 2 is a schematic cross-sectional view showing a configuration example of the A-A' cross-section shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view showing the connector 30 formed on the p-type electrode 16 shown in FIG. 2 in an enlarged manner.

[0015] Note that the ultraviolet light-emitting element 1 is not limited to the embodiments shown below. In the example of this embodiment, the ultraviolet light-emitting element 1 will be described as a PN junction type light-emitting diode. Note that in the embodiments shown below, although technically preferable limitations are imposed to implement the ultraviolet light-emitting element 1, this limitation is not an essential requirement of the ultraviolet light-emitting element 1.

[0016] As shown in FIG. 1, the ultraviolet light-emitting element 1 includes a semiconductor chip 10, a circuit board 20, and a connector 30. The connector 30 includes a plurality of n-type connectors 31 (31A to 31D) that are connectors 30 connecting the n-type electrode 15 of the semiconductor chip 10 and the n-type electrode 22 of the circuit board 20, and a plurality of p-type connectors 32 (32A to 32P) that are connectors 30 connecting the p-type electrode 16 of the semiconductor chip 10 and the p-type electrode 23 of the circuit board 20. Hereinafter, each of the semiconductor chip 10, the circuit board 20, and the connector 30 will be described.

[0017] [Semiconductor Chip] Hereinafter, the specific structure of the semiconductor chip 10 will be described with reference to FIG. 2.

[0018] The semiconductor chip 10 of the present disclosure emits light having a peak wavelength in the ultraviolet range (200 nm to 380 nm). Such a semiconductor chip 10 can use, for example, an ultraviolet LED (Light-Emitting Diode). In particular, an ultraviolet LED having a wavelength of 220 nm or more and less than 240 nm, which has a high sterilization effect, is preferable. Here, there are various theories about the wavelength of the wavelength component harmful to the human body. For example, it may be in the range of 220 nm or more and 230 nm or less, or it may be in the range of 220 nm or more and 235 nm or less. In the present disclosure, in order to be widely applicable to various theories, ultraviolet light having a wavelength of 220 nm or more and less than 240 nm is defined as preferable. Further, since the ultraviolet LED has higher luminous efficiency as the wavelength is longer, an ultraviolet LED having a wavelength of 225 nm or more and less than 240 nm is more preferable.

[0019] As shown in FIG. 2, the semiconductor chip 10 includes a chip substrate 11, an n-type semiconductor layer (first conductivity type semiconductor layer) 12, a semiconductor active layer 13, a p-type semiconductor layer (second conductivity type semiconductor layer) 14, an n-type electrode 15, and a p-type electrode 16. In the semiconductor chip 10, the n-type semiconductor layer 12 is formed on one surface of the chip substrate 11. The semiconductor chip 10 is provided with a semiconductor mesa structure portion 17 formed by a part of the n-type semiconductor layer 12, the semiconductor active layer 13, and the p-type semiconductor layer 14. The semiconductor chip 10 has a region S1 (see FIG. 2) having a portion 12A where the thickness of the chip is relatively thick due to the semiconductor mesa structure portion 17, and a region S2 (see FIG. 2) where the semiconductor mesa structure portion 17 is not provided and the thickness of the chip is thinner than that of the region S1 and has a portion 12B. That is, in the region S1 where the thickness of the chip is relatively thick as described above, the n-type semiconductor layer 12 is thinner than in the region S2 where the thickness of the chip is relatively thin. The n-type electrode 15 is formed in a thin portion of the n-type semiconductor layer 12 in the region S2. The p-type electrode 16 is formed on the p-type semiconductor layer 14 (on the semiconductor mesa structure portion 17) in the region S1. The semiconductor chip 10 has an insulating layer that insulates the thick portion of the n-type semiconductor layer 12, the semiconductor active layer 13, the p-type semiconductor layer 14, the p-type electrode 16, and the n-type electrode 15 (not shown in FIG. 2).

[0020] <Electrode> As shown in FIG. 1, the p-type electrode 16 has straight portions (p-type electrode straight portions 16A to 16D) of a plurality of p-type electrodes 16 that linearly extend in the left-right direction of FIG. 1, and a straight portion (p-type electrode straight portion 16E) of the p-type electrode 16 that linearly extends in the up-down direction of FIG. 1 and connects the p-type electrode straight portions 16A to 16D. The n-type electrode 15 has a configuration in which an end portion on the side opposite to a location (a convex portion shown in FIG. 1, hereinafter referred to as an end portion 16F) adjacent to the n-type electrode straight portions 15A of the p-type electrode straight portions 16A to 16D is connected by the p-type electrode straight portion 16E.

[0021] Further, the n-type electrode 15 is disposed on the extension lines of the p-type electrode straight portions 16A to 16D, and has a straight portion of the n-type electrode 15 (n-type electrode straight portion 15A) that linearly extends in a direction perpendicular to the extending direction of the p-type electrode straight portions 16A to 16D (the vertical direction in FIG. 1), and a plurality of n-type electrode straight portions 15B to 15F that linearly extend in the left-right direction in FIG. 1 and are connected by the n-type electrode straight portion 15A. One ends of the n-type electrode straight portions 15B to 15F of the n-type electrode 15 are connected by the n-type electrode straight portion 15A. The n-type electrode straight portions 15B to 15F and the p-type electrode straight portions 16A to 16D that linearly extend in the left-right direction in FIG. 1 are alternately arranged in the vertical direction in FIG. 1 in a top view.

[0022] The portions of the p-type electrode straight portions 16A to 16D adjacent to the n-type electrode straight portion 15A (the convex portions shown in FIG. 1, hereinafter referred to as the end portions 16F) are surrounded by the n-type electrode 15 in three directions. As described above, it has a convex shape with a semi-circular roundness protruding toward the n-type electrode straight portion 15A side. The end portion 16F having such a convex shape has a greater current concentration in the ultraviolet light emitting element 1 than when the end portion is not convex. That is, when a current is passed through the ultraviolet light emitting element 1, the current concentrates on the end portion 16F of the p-type electrode 16, and local heat generation easily occurs at the end portion 16F. When the p-type electrode 16 locally generates heat, the luminous efficiency of the ultraviolet light emitting element 1 decreases due to a phenomenon called "thermal droop". Also, near the end portion 16F of the p-type electrode 16 that locally generates heat, element breakdown easily occurs, and as a result, the life of the ultraviolet light emitting element 1 is shortened.

[0023] Therefore, in the ultraviolet light emitting element 1 of the present embodiment, by arranging and designing the shape of the connection body (bump) 30 that enhances the heat dissipation at the end portion 16F where the current concentrates, the heat generated in the semiconductor chip 10 is efficiently dissipated to the circuit board 20 side. Specifically, by making the structure of the connection body 30 disposed at a position close to the end portion 16F where the current concentrates different from the connection body 30 disposed at a position away from the end portion 16F where the current concentrates, the heat dissipation of the end portion 16F where heat generation concentrates is enhanced compared to the heat dissipation of the straight portions other than the end portion 16F. As described above, in the ultraviolet light-emitting element 1 having the end portion 16F with a convex shape, the concentration of current in the ultraviolet light-emitting element 1 is greater than that in the case where the end portion does not have a convex shape. Therefore, the light-emitting efficiency improvement and the lifetime extension effect by the connector 30 of the present embodiment with a high heat dissipation promoting effect are enhanced.

[0024] The n-type electrode 15 and the p-type electrode 16 as described above are preferably formed of a material that provides an ohmic contact with a semiconductor layer such as a stacked thin film in contact therewith. Examples of the material constituting the n-type electrode 15 include Ti, Al, Ni, Au, Cr, V, Zr, Hf, Nb, Ta, Mo, W, or an alloy thereof, or ITO. A material containing aluminum and nickel is more preferable from the viewpoint of reducing the contact resistance. Examples of the material constituting the p-type electrode 16 include Ni, Au, Pt, Ag, Rh, Pd, Pt, Cu, and an alloy thereof, or ITO. When the p-type semiconductor layer 14 is a nitride semiconductor layer, the material constituting the electrode in contact with the nitride semiconductor layer is preferably Ni, Au, or an alloy thereof, or ITO, which has a small contact resistance with the nitride semiconductor layer. The n-type electrode 15 and the p-type electrode 16 may be configured such that a metal layer such as Au, Al, Cu, Ag, or W is continuously formed for connection to the semiconductor layer. In some cases, it is desirable to use Au, which has high conductivity, for the n-type electrode 15 and the p-type electrode 16. Further, in order to improve the adhesion to the semiconductor layer, the n-type electrode 15 and the p-type electrode 16 may further have a metal layer formed of Ti at the interface with the semiconductor layer.

[0025] <Chip Substrate> The chip substrate 11 only needs to be capable of arranging a stacked thin film such as the semiconductor active layer 13 including the light-emitting layer on the first main surface 11A facing the circuit substrate 20, and the shape is not particularly limited. The chip substrate 11 is formed of a material that transmits the light emitted from the light-emitting layer, and emits light in the direction of the second main surface 11B on the side opposite to the light-emitting layer of the chip substrate 11. From the viewpoint of arranging a laminated thin film such as a semiconductor active layer 13 including a light-emitting layer made of AlGaN which is a light-emitting material in the ultraviolet region, the chip substrate 11 is preferably a sapphire substrate or an aluminum nitride substrate. The aluminum nitride substrate is preferably a single crystal aluminum nitride substrate.

[0026] Also, a protective film (not shown) may be arranged on the surface of the chip substrate 11 other than the first main surface 11A. As the material of the protective film, silicon dioxide, silicon nitride, etc. can be used, but it is not limited to these materials. By arranging a protective film on the surface of the chip substrate 11 other than the first main surface 11A, it is possible to prevent a reduction in the light emission efficiency and extraction efficiency of light having a desired wavelength. This is due to the following reasons. When the surface of the chip substrate 11 other than the first main surface 11A is exposed to the outside world, if the chip substrate 11 is a sapphire substrate, the chip substrate 11 may react with water or the like in the outside world due to the heat generation of the semiconductor chip 10, and a hydroxide film may be formed on the exposed surface of the chip substrate 11. Also, if the chip substrate 11 is an aluminum nitride substrate, an oxide film may be formed due to the reaction of the chip substrate 11 with oxygen in the outside world due to the heat generation of the semiconductor chip 10. These films (hydroxide film or oxide film) attenuate or reflect the light including the center wavelength of the emission spectrum, reducing the light emission efficiency of the light having a desired wavelength, that is, decreasing the output. These films may contain carbon derived from carbon dioxide in the outside world or carbon mixed as an impurity in the chip substrate, or carbon derived from the resin used in the package of the semiconductor chip 10 at the time of formation. As a result, even if the band gap energy of each film is larger than the emission energy, light absorption due to impurities occurs and light attenuation occurs.

[0027] Further, when a layer with a different refractive index is formed on the first main surface 11A of the chip substrate 11, reflection occurs at the interface between the chip substrate 11 and the layer with a different refractive index when light is incident. In particular, for example, when an aluminum nitride substrate is used as the chip substrate 11 and a material with a lower refractive index than the chip substrate 11, such as an aluminum oxide layer, is formed on the first main surface 11A of the chip substrate 11, the reflection of the incident light occurs more strongly, and light in a desired wavelength range cannot be extracted from the second main surface 11B of the chip substrate 11 to the outside. From the viewpoint of preventing these, it is preferable to dispose a protective film on the surface of the chip substrate 11.

[0028] The dislocation density of the chip substrate 11 is preferably less than 10 7 cm -2 and particularly preferably less than 10 5 cm -2 From the viewpoint of reducing the dislocation density of the laminated thin film laminated on the first main surface 11A of the chip substrate 11, the root mean square (RMS) height (Rq) of the first main surface 11A of the chip substrate 11 is preferably less than about 1 nm with respect to an area of 10 μm × 10 μm. Further, in order to form the thin film surface flat and uniform, the root mean square (RMS) height of the second main surface 11B of the chip substrate 11 is preferably less than about 10 nm with respect to an area of 10 μm × 10 μm.

[0029] The chip substrate 11 according to the present embodiment may have a convex portion or a concave portion having a convex shape or a concave shape on the second main surface 11B. The convex portion may be provided in various convex shapes such as a cone, a pyramid, a hemisphere, a frustum of a cone, etc. and at various densities. When the chip substrate 11 is made of AlN, from the viewpoint of realizing a convex shape with high physical resistance and chemical resistance due to a stable crystal plane, the convex portion preferably includes a pyramid shape whose side surface is composed of (10-1-1) planes. From this viewpoint, the convex portion is more preferably a hexagonal pyramid or a frustum of a hexagonal pyramid reflecting the stable plane of the hexagonal crystal structure. A plurality of such convex portions may be formed. When a plurality of convex portions are formed, the convex portions may be formed in one shape or a plurality of shapes may be mixed.

[0030] The concave portions may be recessed in various shapes such as a cone, a pyramid, a hemisphere, a truncated cone, etc., or provided with various densities. When the chip substrate is made of AlN, from the viewpoint of realizing a concave shape with high physical and chemical resistance due to a stable crystal plane, the concave portion preferably includes a shape recessed in a pyramidal shape whose side surface is composed of the (10-1-1) plane. From this viewpoint, the concave portion is more preferably a hexagonal pyramid or a hexagonal truncated pyramid shape reflecting the stable plane of the hexagonal crystal structure. A plurality of such concave portions may be formed. When a plurality of concave portions are formed, they may be formed in one shape or a plurality of shapes may be mixed.

[0031] The sizes of the convex and concave portions are not particularly limited, but are preferably 0.01 μm or more and 5 μm or less in height, and more preferably 0.1 μm or more and 3 μm or less. The sizes of the convex and concave portions can be measured from an image when observing the surface of the convex or concave portion with an electron beam scanning microscope (SEM: Scanning Electron Microscope) at a magnification of 20,000 times. In the present embodiment, by having the concavo-convex structure on the second main surface 11B of the chip substrate 11, the light emission intensity of the ultraviolet light emitting element 1 of the present disclosure can be increased.

[0032] <Stacked thin film> The stacked thin film includes a light emitting layer and is not particularly limited as long as it is disposed on the first main surface 11A of the chip substrate 11. From the viewpoint of improving the light emission efficiency, the stacked thin film preferably further includes an n-type semiconductor layer 12 which is a first conductive type semiconductor layer and a p-type semiconductor layer 14 which is a second conductive type semiconductor layer so as to sandwich a semiconductor active layer 13 including a light emitting layer. Here, "first conductive type" and "second conductive type" mean semiconductors having different conductivity. When one is n-type conductivity, the other is p-type conductivity. Generally, an n-type semiconductor layer is provided between the semiconductor active layer 13 and the chip substrate 11, but the present embodiment is not limited thereto. It is preferable to use AlGaN which is a mixed crystal of Al, Ga, and N for the stacked thin film, and it is more preferable to stack AlGaN on the +c plane.

[0033]

[0033] As layers other than the n-type semiconductor layer 12, the semiconductor active layer 13 including a light-emitting layer, and the p-type semiconductor layer 14, for example, a layer that blocks electrons or holes may be provided between the semiconductor active layer 13 and at least one of the n-type semiconductor layer 12 and the p-type semiconductor layer 14. Also, from the viewpoint of improving the crystallinity of the laminated thin film, it may be preferable to further provide a buffer layer on the surface of the laminated thin film in contact with the chip substrate 11. Further, from the viewpoint of efficiently supplying power to the semiconductor active layer 13, an n-type electrode 15 in contact with the n-type semiconductor layer 12 and a p-type electrode 16 in contact with the p-type semiconductor layer 14 are provided.

[0034]

[0034] The laminated thin film can be formed by an apparatus using the MOCVD (Metal Organic Chemical Vapor Deposition) method, the MBE (Molecular Beam Epitaxy) method, or a sputtering apparatus. However, from the viewpoint of growing a high-quality thin film, it is preferably grown by an MOCVD apparatus. The laminated thin film having a mesa structure can be formed by etching a desired region after forming the thin film layers constituting the laminated thin film by the above-described MOCVD method or the like.

[0035] (Semiconductor active layer) The semiconductor active layer 13 emits light corresponding to the bandgap of the light-emitting layer when power is applied to the light-emitting layer included in the semiconductor active layer 13. The light-emitting layer included in the semiconductor active layer 13 of the semiconductor chip 10 of the present embodiment is not particularly limited as long as the peak wavelength of the emission spectrum is in the ultraviolet region. Here, when the emission spectrum has a plurality of peaks, the wavelength of the peak having the highest emission intensity in the wavelength region of ultraviolet light is defined as the emission wavelength of the ultraviolet light-emitting element. As an example of the specific structure of the light-emitting layer, a quantum well structure can be mentioned. For example, a quantum well structure in which AlGaN layers with different composition ratios (different bandgaps) are stacked can be adopted. More preferably, a multiple quantum well in which multiple AlGaN layers with different composition ratios (different bandgaps) are stacked can be adopted. As a more specific structure, the composition is Al 0.83 Ga 0.17 N well layers (thickness 1 nm) in three layers and Al 0.9 Ga 0.1 N barrier layers (thickness 5 nm) in two layers are alternately stacked to form a triple quantum well structure.

[0036] (n-type semiconductor layer) Examples of the n-type semiconductor layer 12 include single crystals and mixed crystals of AlN, GaN, and InN, and combinations (multilayers) thereof may also be acceptable. When the chip substrate 11 is an aluminum nitride substrate, AlGaN with an Al / (Al + Ga) ratio of 0.8 or more, which has a small difference in lattice constant, is preferable as the n-type semiconductor layer. As shown in FIG. 2, the n-type semiconductor layer has a region S1 formed by removing a part of the n-type semiconductor layer and a region S2 located on the region S1 and constituting the semiconductor mesa structure portion. Examples of the n-type semiconductor constituting the n-type semiconductor layer 12 include AlGaN doped with Si at a concentration of 1×10 19 cm -3 . Also, as the n-type semiconductor, AlGaN n-type doped by the polarization doping method in which the mixed crystal composition ratio of the polar mixed crystal semiconductor is continuously changed may be used. In addition, when a p-type semiconductor layer using a p-type semiconductor as the first conductive type semiconductor layer is formed on the chip substrate 11, for example, Mg at 3×10 19 cm -3AlGaN doped at the concentration of can be used. Further, as the p-type semiconductor, AlGaN p-type doped by the polarization doping method of continuously changing the mixed crystal composition ratio of the polar mixed crystal semiconductor may be used. From the viewpoint of efficiently transporting carriers to the semiconductor active layer 13 that emits light having a peak wavelength of less than 240 nm, it is preferable to use AlGaN having an Al / (Al+Ga) ratio of 0.8 or more as the semiconductor thin film provided between the chip substrate 11 and the semiconductor active layer 13.

[0037] (p-type semiconductor layer) Examples of the p-type semiconductor layer 14 include single crystals and mixed crystals of AlN, GaN, and InN, and combinations (multi-layers) thereof may also be used. As the p-type semiconductor constituting the p-type semiconductor layer, for example, AlGaN doped at a concentration of Mg of 3×10 19 cm -3 can be used. From the viewpoint of reducing the contact resistance with the p-type electrode 16, the p-type semiconductor layer may have an AlGaN gradient composition in which the Al / (Al+Ga) ratio continuously or stepwise decreases in the direction away from the chip substrate 11. Further, from the viewpoint of suppressing the movement of electrons and holes that reduce the emission efficiency, the p-type semiconductor layer may have a barrier layer (not shown) with a large bandgap on the semiconductor active layer 13 side. Further, from the viewpoint of reducing the contact resistance with the p-type electrode 16, the p-type semiconductor layer 14 may have a contact layer (not shown) doped with a large amount of impurities on the p-type electrode 16 side. In addition, when forming an n-type semiconductor layer using an n-type semiconductor as the second conductive type semiconductor layer on the upper layer of the semiconductor active layer 13, for example, AlGaN doped at a concentration of Si of 1×10 19 cm -3 can be used. Further, as the n-type semiconductor, AlGaN n-type doped by the polarization doping method of continuously changing the mixed crystal composition ratio of the polar mixed crystal semiconductor may be used.

[0038] [Circuit board] Hereinafter, with reference to FIG. 2, the specific structure of the circuit board 20, which is a package substrate, will be described.

[0039] The circuit board 20 of this embodiment is, for example, a printed circuit board (PCB), on which conductors are formed on an insulator substrate 21 and electronic components are mounted. Note that the circuit board 20 may be a printed wiring board (PWB) on which no electronic components are mounted. The conductors include an n-type electrode 22 that is electrically connected to the n-type electrode 15 of the semiconductor chip 10, and a p-type electrode 23 that is electrically connected to the p-type electrode 16 of the semiconductor chip 10.

[0040] As shown in FIG. 2, among the p-type electrodes 23 formed on the circuit board 20, the portions that face the p-type electrode straight portions 16A to 16D, that is, the portions that contact the p-type connectors 32 (p-type connectors 32A to 32P), are formed such that the thickness of the p-type electrode 23 increases as it approaches the ends 16F of the p-type electrode straight portions 16A to 16D. Thereby, in the ultraviolet light emitting element 1 of this embodiment, the distance between the semiconductor chip 10 and the circuit board 20 decreases as it approaches the ends 16F of the p-type electrode straight portions 16A to 16D. For this reason, the height of the p-type connectors 32A to 32P can be lowered as it approaches the ends 16F of the p-type electrode straight portions 16A to 16D, and p-type connectors 32A to 32P with low thermal resistance and high heat dissipation can be obtained. Further, when the amounts of the conductive materials constituting the respective p-type connectors 32A to 32P are made uniform, the contact areas between the p-type connectors 32A to 32P and the p-type electrode straight portions 16A to 16D and the contact areas between the p-type connectors 32A to 32P and the p-type electrode 23 increase as it approaches the ends 16F. For this reason, the heat dissipation of the p-type connectors 32A to 32P can be improved as it approaches the ends 16F.

[0041] [Connector] As shown in FIGS. 1 and 2, the connector 30 includes a plurality of n-type connectors 31 (31A to 31D) that are the connectors 30 connecting the n-type electrode 15 of the semiconductor chip 10 and the n-type electrode 22 of the circuit board 20, and a plurality of p-type connectors 32 (32A to 32P) that are the connectors 30 connecting the p-type electrode 16 of the semiconductor chip 10 and the p-type electrode 23 of the circuit board 20.

[0042] The n-type electrode 15 of the semiconductor chip 10 and the n-type electrode 22 of the circuit board 20 are connected by a plurality of n-type connectors 31 (31A to 31D). The n-type connectors 31 (31A to 31D) are arranged at regular intervals and separated from each other at positions on the n-type electrode straight portion 15A on the semiconductor chip 10. The connection surface between the semiconductor chip 10 and each of the n-type connectors 31 (31A to 31D) is circular. Also, the connection surface between the circuit board 20 and each of the n-type connectors 31 (31A to 31D) is similarly circular.

[0043] The p-type electrode 16 of the semiconductor chip 10 and the p-type electrode 23 of the circuit board 20 are connected by a plurality of p-type connectors 32 (32A to 32P). The p-type connectors 32 (32A to 32P) are arranged at regular intervals and separated from each other at positions on the p-type electrode straight portions 16A to 16D on the semiconductor chip 10. The connection surface between the semiconductor chip 10 and each of the p-type connectors 32 (32A to 32P) is circular. Also, the connection surface between the circuit board 20 and each of the p-type connectors 32 (32A to 32P) is similarly circular.

[0044] The p-type connectors 32 (32A to 32P) are connected to all of the plurality of p-type electrode straight portions 16A to 16D of the semiconductor chip 10. In all of the p-type connectors 32 (32A to 32P), from the side far from the end portion 16F to the side close to it (from right to left in FIG. 1), that is, the closer to the n-type electrode straight portion 15A, the larger the contact area between each of the p-type connectors 32 (32A to 32P) and the semiconductor chip 10. That is, for example, toward the end portion 16F of the p-type electrode straight portion 16A, the contact area between the p-type electrode straight portion 16A and the p-type connectors 32D, 32C, 32B, 32A increases in this order. Therefore, at the end portion 16F of the p-type electrode straight portions 16A to 16D where the current is most concentrated and the heat generation is large, the contact area between the p-type connector 32 and the semiconductor chip 10 is the largest, and the heat dissipation property is high. Thereby, in the ultraviolet light emitting element 1 that locally generates high heat at the end portion 16F of the p-type electrode straight portions 16A to 16D, the non-uniformity of the heat distribution in the ultraviolet light emitting element 1 can be alleviated.

[0045] As described above, since the end portions 16F of the p-type electrode straight portions 16A to 16D adjacent to the n-type electrode straight portion 15A have a convex shape with a semi-circular roundness, the concentration of current in the ultraviolet light emitting element 1 is greater than that in the case where the tip is not convex. Therefore, in the ultraviolet light emitting element 1 of the present embodiment where the end portion 16F has a convex shape, the effect of improving the light emission efficiency and extending the life by maximizing the bonding area between the p-type connector 32 (32A, 32E, 32I, 32M) and the p-type electrode 16 at the end portion 16F and promoting heat dissipation is significant.

[0046] Also, in the ultraviolet light emitting element 1, the contact area between the p-type connector 32 (32A to 32P) and the p-type electrode 23 of the circuit board 20 gradually increases toward the end portion 16F of the p-type electrode straight portions 16A to 16D. Therefore, the contact area between the p-type connector 32 and the circuit board 20 is the largest at the end portion 16F of the p-type electrode straight portions 16A to 16D where the current is most concentrated and the heat generation is the largest, and the heat dissipation property is high. As a result, in the ultraviolet light emitting element 1 that locally generates high heat at the end portion 16F of the p-type electrode straight portions 16A to 16D, the heat of the semiconductor chip 10 can be efficiently dissipated to the circuit board 20 side, and the non-uniformity of heat in the ultraviolet light emitting element 1 can be alleviated.

[0047] In the ultraviolet light-emitting element 1, toward the ends 16F of the p-type electrode straight portions 16A to 16D, the height of the p-type connectors 32 (32A to 32P) is low, that is, the distance between the semiconductor chip 10 and the circuit board 20 is close. Although the p-type connectors 32 have a heat dissipation function, they also act as a thermal resistance when transmitting heat. The lower the height of the p-type connectors 32, the lower the thermal resistance and the higher the heat dissipation performance. In the ultraviolet light-emitting element 1, the height of the p-type connector 32A disposed at the end 16F of the p-type electrode straight portions 16A to 16D where the current is most concentrated and the heat generation is large is lower than the heights of the p-type connectors 32B, 32C, and 32D disposed at positions away from the end 16F, and the heat dissipation performance is high. Thereby, in the ultraviolet light-emitting element 1 that locally generates high heat, the heat of the semiconductor chip 10 can be efficiently dissipated to the circuit board 20 side, and the non-uniformity of heat within the ultraviolet light-emitting element 1 can be alleviated.

[0048] In the ultraviolet light-emitting element 1, the contact area between the p-type connector 32 and the p-type electrode 23 of the circuit board 20 is larger than the contact area between the p-type connector 32 and the p-type electrode 16 of the semiconductor chip 10. In many cases, since the semiconductor chip 10 often has a more complex and finer electrode pattern of the n-type electrode 15 and the p-type electrode 16 than the circuit board 20, the smaller contact area of the p-type connector 32 on the semiconductor chip 10 side has the effect of increasing the design freedom on the semiconductor chip 10 side.

[0049] Also, in the ultraviolet light-emitting element 1, the p-type connector 32 is thick on the circuit board 20 side and thin on the semiconductor chip 10 side. Specifically, as shown in FIG. 3, the p-type connector 32 has a cross-sectional shape in which the lower cylinder 321 on the circuit board 20 side and the upper cylinder 322 on the semiconductor chip 10 side overlap. Here, the lower cylinder 321 and the upper cylinder 322 do not necessarily have a precise cylindrical shape, and it is sufficient that they have a substantially cylindrical shape. With this structure, even if the height of the p-type connector 32 changes due to an error in the manufacturing apparatus when manufacturing the ultraviolet light-emitting element 1, the change in the contact area between the p-type connector 32 and the semiconductor chip 10 can be made smaller compared to the change in the contact area between the p-type connector 32 and the circuit board 20. As a result, a more complex and detailed electrode shape can be designed on the semiconductor chip 10 side, improving the design freedom.

[0050] In the ultraviolet light-emitting element 1, as shown in FIG. 3, in the p-type connector 32, a space region 323 where the upper cylinder 322 does not exist is formed on the lower cylinder 321. This space region 323 becomes smaller as the p-type connector 32 is closer to the n-type electrode straight portion 15A. With such a structure of the p-type connector 32, since the space region 323 with low heat dissipation becomes smaller as it is closer to the end 16F of the p-type electrode straight portions 16A to 16D, heat can be dissipated more efficiently as it is closer to the n-type electrode 15, that is, closer to the end 16F of the p-type electrode straight portions 16A to 16D that locally generate high heat. In FIG. 1, although the outer contour line of the semiconductor mesa structure portion 17 of the semiconductor chip 10 shown in FIG. 2 is not shown, the outer contour line of the semiconductor mesa structure portion 17 is located between the n-type electrode 15 and the p-type electrode 16 in FIG. 1.

[0051] Such a connector 30 can be manufactured as follows. The method for forming the n-type connector 31 and the p-type connector 32, which are the connectors 30, is not particularly limited. For example, there are methods of melting a metal wire using heat or ultrasonic waves, or both, and fixing one end of the metal wire to an electrode, and methods of depositing Au by electroless plating. In addition, examples of the metal forming the n-type connector 31 and the p-type connector 32 include Pb, Al, Cu, Ag, Au, or alloys thereof, but it is desirable to use Au, which has high thermal conductivity, excellent corrosion resistance, and is easy to bond. That is, it is preferable that the main component of the n-type connector 31 and the p-type connector 32, which also have the function of a heat dissipation metal body, is gold (Au).

[0052] Here, the n-type electrode straight portion 15A of the semiconductor chip 10 extends in a direction intersecting the extension lines of each of the p-type electrode straight portions 16A to 16D. Note that FIG. 1 shows a configuration in which the n-type electrode straight portion 15A extends in a direction perpendicular to the extension lines of each of the p-type electrode straight portions 16A to 16D. The semiconductor chip 10 and the circuit board 20 are flip-chip bonded by a connecting body 30. In order to increase the contact area between the p-type connecting body 32 disposed on the p-type electrode 16 (p-type electrode straight portions 16A to 16D) and the semiconductor chip 10 as it approaches the n-type electrode straight portion 15A, the following manufacturing methods can be mentioned. When forming the p-type connecting body 32, by reducing the pressure applied to the p-type electrode straight portions 16A to 16D of the circuit board 20 with a metal wire, or shortening the pressing time, the outer shape (diameter) of the p-type connecting body 32, which is circular in plan view, can be made smaller. That is, as it approaches the n-type electrode straight portion 15A, the diameter of the p-type connecting body 32 can be increased by increasing the forming time and the pressing pressure of the p-type connecting body 32. When performing flip-chip bonding between the semiconductor chip 10 and the circuit board 20 in this state, an ultraviolet light emitting element 1 can be formed in which the contact area between the p-type electrode straight portions 16A to 16D disposed on the p-type electrode 16 and the semiconductor chip 10 increases as it approaches the n-type electrode straight portion 15A.

[0053] Also, as another method, there is a method of increasing the size of the opening of the solder mask used when forming the p-type connecting body 32 with solder as it approaches the n-type electrode straight portion 15A. In this case, a solder metal corresponding to the outer shape of the opening of the solder mask can be formed on the semiconductor chip 10 or the circuit board 20. By using these techniques, it is also possible to increase the contact area between the p-type connecting body 32 and the p-type electrode 16 of the semiconductor chip 10 and the p-type electrode 23 of the circuit board 20 as it approaches the n-type electrode straight portion 15A of the semiconductor chip 10.

[0054] In order to make the end portions 16F of the p-type electrode straight portions 16A to 16D convex, for example, when forming the p-type electrode straight portions 16A to 16D using lithography technology, the shape of the photomask used may be designed such that the end portions 16F have a convex shape. In this case, for example, when using a positive resist, the resist in the opening of the photomask is dissolved by being immersed in the developer, and by performing film formation of the p-type electrode 16 and lift-off of the resist, a p-type electrode 16 having convex end portions 16F can be formed.

[0055] In order to make the height of the p-type connection body 32 decrease as it approaches the n-type electrode straight portion 15A, for example, as shown in FIG. 2, the film thickness of the p-type electrode 23 on the circuit board 20 may be made thicker as it approaches the n-type electrode straight portion 15A. Thereby, the height of the p-type connection body 32 formed on the p-type electrode 23 of the circuit board 20 can be made lower as it approaches the n-type electrode straight portion 15A. In order to form the p-type connection body 32 in which the space region 323 is formed, as shown in FIG. 3, the conditions of the p-type connection body 32 forming step and the bonding step (flip chip step) of the semiconductor chip 10 and the circuit board 20 may be optimally designed. Specifically, in the p-type connection body 32 forming step, after pressing a metal wire against the p-type electrode 23 of the circuit board 20 facing the p-type electrode straight portions 16A to 16D to produce a metal spherical shape, by pulling up the wire at an appropriate speed, a metal material having a shape with a larger diameter on the circuit board 20 side and a smaller diameter than that on the circuit board 20 side on the semiconductor chip 10 side (a shape whose cross section is close to a convex shape) is formed. Subsequently, the semiconductor chip 10 and the circuit board 20 are pressed against each other with a force that does not deform the metal material having a shape whose cross section is close to a convex shape into a spherical shape. Thereby, it becomes possible to form a p-type connection body 32 in a shape where the lower cylinder 321 on the circuit board 20 side and the upper cylinder 322 on the semiconductor chip 10 side overlap.

[0056] Note that the method for forming the p-type connection body 32 in which the space region 323 is formed is not limited to the method described above. For example, a metal fine wire is pressed onto the p-type electrode 23 of the circuit board 20 facing the p-type electrode straight portions 16A to 16D to produce a metal spherical shape. After that, a metal material that will become the lower cylinder 321 is disposed, and then a metal spherical shape having a diameter smaller than that of the metal spherical shape on the p-type electrode 23 is produced at a predetermined position on the p-type electrode straight portions 16A to 16D of the semiconductor chip 10. Subsequently, the semiconductor chip 10 and the circuit board 20 are pressed against each other with a force such that the metal spherical shape with a smaller diameter on the semiconductor chip 10 side and the metal spherical shape with a larger diameter on the circuit board 20 side do not form one sphere (do not completely integrate and change into a spherical shape). Also by this method, it becomes possible to form the p-type connection body 32 having a shape in which the lower cylinder 321 on the circuit board 20 side and the upper cylinder 322 on the semiconductor chip 10 side overlap.

[0057] By forming the p-type connection body 32 in such a manner, it is possible to form the p-type connection body 32 having the space region 323 which is a region without the upper cylinder 322 on the lower cylinder 321. Furthermore, in addition to this p-type connection body 32 forming technique and the flip chip technique, by making the film thickness of the p-type electrode 23 on the circuit board 20 thicker as it approaches the n-type electrode straight portion 15A, the space region 323 becomes smaller as it approaches the n-type electrode straight portion 15A, and it also becomes possible to manufacture the ultraviolet light emitting element 1 with improved discharge properties.

[0058] Generally, in a semiconductor light emitting element that generates light in the ultraviolet region, a nitride semiconductor is used as a material. And, the shorter the emission wavelength, the higher the Al composition, such as AlGaN or AlN, is used. These materials have a larger parasitic resistance when used as a semiconductor light emitting element than GaN or InGaN which are visible light emitting materials, and heat dissipation of the semiconductor light emitting element is important. This amount of heat generation becomes larger especially as the emission wavelength of ultraviolet light becomes shorter, and as a result, the power consumption of the semiconductor light emitting element becomes larger. That is, the shorter the emission wavelength of the light emitted from the ultraviolet light emitting element 1 of the present disclosure, the higher the effect by using the p-type connection body 32 described above becomes.

[0059] (1.2) Modification (1.2.1) Modification Example 1 In the ultraviolet light-emitting element 1 according to the present embodiment, as shown in FIG. 2, the n-type connector 31 is shown in a shape having the same spatial region as the p-type connector 32. However, the shape of the n-type connector 31 is not limited to such a shape and may be a cylindrical shape without a spatial region. For example, as shown in FIG. 4, the ultraviolet light-emitting element 1A according to Modification Example 1 may include an n-type connector 131 (n-type connectors 131A to 131D) that is substantially cylindrical and has no spatial region like the p-type connector 32, instead of the n-type connector 31 having the same shape as the p-type connector 32. Note that in FIG. 4, the n-type connectors 131B to 131D are not shown. To form the n-type connector 131 without a spatial region, a metal wire is pressed onto the n-type electrode 22 of the circuit board 20 facing the straight portion 15A of the n-type electrode to produce a metal sphere, and then the semiconductor chip 10 and the circuit board 20 are pressed against each other while maintaining the shape of the metal sphere. Thereby, a cylindrical n-type connector 131 without a spatial region can be formed.

[0060] In the ultraviolet light-emitting element 1 provided with the n-type connector 31 having the same shape as the p-type connector 32 as shown in FIG. 2, the forming method when forming each connector (the n-type connector 31 and the p-type connector 32) can be formed without changing the forming method for each connector. On the other hand, when forming the n-type connector 131, it is necessary to change the arrangement method of the conductive material between the conductive material such as a metal material arranged at the position where the p-type connector 32 is formed and the conductive material arranged at the position where the n-type connector 131 is formed. Therefore, it is preferable to use the n-type connector 31 having the same shape as the p-type connector 32 in that the manufacturing process does not become complicated.

[0061] (1.2.2) Modification Example 2 In the ultraviolet light-emitting element 1 according to the present embodiment, as shown in FIG. 2, the heat dissipation property of the p-type connectors 32A to 32P is improved as approaching the end portions 16F of the p-type electrode straight portions 16A to 16D by increasing the contact areas between the p-type connectors 32A to 32P and the p-type electrode straight portions 16A to 16D and between the p-type connectors 32A to 32P and the p-type electrode 23 as approaching the end portions 16F. In order to achieve such a configuration, in the ultraviolet light-emitting element 1, the amount of the conductive material constituting each of the p-type connectors 32A to 32P is made uniform, and the thickness of the p-type electrode 23 is increased as approaching the end portions 16F of the p-type electrode straight portions 16A to 16D. However, the present invention is not limited to such a configuration.

[0062] For example, as shown in FIG. 5, in the ultraviolet light-emitting element 1B according to the second modification, among the p-type electrodes 23 formed on the circuit board 20, the portion in contact with the p-type connectors 132 (p-type connectors 132A to 132P) has a constant thickness, and the p-type connectors 132 (p-type connectors 132A to 132P) are formed larger as approaching the end portions 16F. Note that in FIG. 5, the p-type connectors 132D to 132P are not shown. Such p-type connectors 132 (p-type connectors 132A to 132P) can be formed by increasing the pressure or the pressing time for pressing the metal wires against the p-type electrode straight portions 16A to 16D of the circuit board 20 as approaching the end portions 16F when forming the p-type connectors 132. As a result, the contact areas between the p-type connectors 132A to 132P and the p-type electrode straight portions 16A to 16D and between the p-type connectors 132A to 132P and the p-type electrode 23 are increased as approaching the end portions 16F of the p-type electrode straight portions 16A to 16D, and the heat dissipation property of the p-type connectors 132A to 132P can be improved as approaching the end portions 16F. Furthermore, the n-type connector 31 in the ultraviolet light-emitting element 1B may be the substantially cylindrical n-type connector 131 described in the first modification.

[0063] (1.3) Application fields of the ultraviolet light-emitting element of the present disclosure The ultraviolet light-emitting device of the present disclosure is applicable to, for example, devices in the fields of medical and life sciences, environment, industry and industrial, household appliances, agriculture, and other fields. The ultraviolet light-emitting device of the present disclosure is applicable to devices for synthesizing and decomposing drugs and chemical substances, liquid, gas, and solid (containers, foods, medical devices, etc.) sterilization devices, cleaning devices for semiconductors, etc., surface modification devices for films, glass, metals, etc., exposure devices for manufacturing semiconductors, flat panel displays (FPDs), printed circuit boards (PCBs), and other electronic products, printing and coating devices, bonding and sealing devices, transfer and molding devices for films, patterns, mock-ups, etc., and measuring and inspection devices for banknotes, scratches, blood, chemical substances, etc.

[0064] Examples of liquid sterilization devices include, but are not limited to, automatic ice-making devices, ice trays, and ice storage containers in refrigerators, water supply tanks for ice makers, freezers, ice makers, humidifiers, dehumidifiers, cold water tanks, hot water tanks, and flow path pipes of water servers, stationary water purifiers, portable water purifiers, water supply devices, water heaters, wastewater treatment devices, disposers, drain traps of toilets, washing machines, dialysis water sterilization modules, connector sterilizers for peritoneal dialysis, disaster water storage systems, etc.

[0065] Examples of gas sterilization devices include, but are not limited to, air purifiers, air conditioners, ceiling fans, floor and bedding cleaners, futon dryers, shoe dryers, washing machines, clothes dryers, indoor sterilization lamps, ventilation systems for storage rooms, shoe boxes, wardrobes, etc. Examples of solid sterilization devices (including surface sterilization devices) include, but are not limited to, vacuum packers, belt conveyors, hand tool sterilization devices for medical, dental, barber, and beauty parlors, toothbrushes, toothbrush holders, chopstick boxes, cosmetic pouches, drain covers, bidets for toilets, toilet lids, etc.

[0066] As described above, the present disclosure has been described using embodiments. However, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present disclosure.

Explanation of Symbols

[0067] 1 Ultraviolet light-emitting element 10 Semiconductor chip 11 Chip substrate 11A First main surface 11B Second main surface 12 n-type semiconductor layer 13 Semiconductor active layer 14 p-type semiconductor layer 15 n-type electrode 15A~15F n-type electrode straight part 16 p-type electrode 16A~16E p-type electrode straight part 16F End part 17 Semiconductor mesa structure part 20 Circuit board 21 Insulator substrate 22 n-type electrode 23 p-type electrode 30 Connector 31,31A~31D n-type connectors 32,32A~32P p-type connectors 321 Lower cylinder 322 Upper cylinder 323 Space region

Claims

1. A semiconductor chip, A circuit board disposed opposite to the semiconductor chip, A plurality of connectors connecting the semiconductor chip and the circuit board, Characterized in that, On the surface of the semiconductor chip facing the circuit board, there are a first conductivity type electrode and a second conductivity type electrode. The first conductivity type electrode has a first conductivity type electrode straight portion in contact with the connector. The second conductivity type electrode is in contact with the connector and has a second conductivity type electrode straight portion extending in a direction intersecting with the first conductivity type electrode straight portion. A part of the plurality of connectors are second conductivity type electrode straight portion upper connectors disposed in contact with the second conductivity type electrode straight portion, The area of contact of each of the plurality of second conductivity type electrode straight portion upper connectors with the second conductivity type electrode straight portion increases as it approaches the first conductivity type electrode straight portion. An ultraviolet light emitting device.

2. The end of the second conductivity type electrode straight portion adjacent to the first conductivity type electrode straight portion has a convex shape with a semi-circular roundness protruding toward the first conductivity type electrode straight portion side. The ultraviolet light emitting device according to Claim 1.

3. The contact area of each of the second conductivity type electrode straight portion upper connectors with the circuit board increases as it approaches the first conductivity type electrode straight portion. The ultraviolet light emitting device according to Claim 2.

4. The height of each of the second conductivity type electrode straight portion upper connectors disposed between the semiconductor chip and the circuit board decreases as it approaches the first conductivity type electrode straight portion. The ultraviolet light emitting device according to Claim 3.

5. The contact area of each of the second conductivity type electrode straight portion upper connectors with the circuit board is larger than the contact area with the second conductivity type electrode straight portion. The ultraviolet light emitting device according to Claim 4.

6. Each of the second conductivity type electrode straight portion upper connectors has a shape in which a lower cylinder located closer to the circuit board and an upper cylinder located closer to the semiconductor chip and having a smaller outer shape in plan view than the lower cylinder are stacked and overlapped. The ultraviolet light emitting device according to Claim 5.

7. Each of the second conductivity type electrode straight portion upper connectors has a space region which is a region where there is no upper cylinder on the semiconductor chip side of the lower cylinder. The space region becomes smaller as it approaches the first conductivity type electrode straight portion. The ultraviolet light emitting device according to Claim 6.

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