Semiconductor light emitting element and light emitting device

Abstract

To provide a light emitting element or a light emitting device, in which reliability is enhanced and an optical output is improved while achieving thinning.SOLUTION: A semiconductor light emitting element 10 includes: a flat plate-shaped translucent element substrate 11 with two main surfaces 11A, 11B facing each other; a light emitting semiconductor layer 12 which is formed on one main surface 11A of the element substrate 11 and in which an n-type semiconductor layer 13, a light emitting layer 14, and a p-type semiconductor layer 15 are laminated; an n-electrode 16 which is connected to the n-type semiconductor layer 13 through at least one hole portion 12A leading to the n-type semiconductor layer 13 and which is provided, on the p-type semiconductor layer 15, to be electrically separated from the p-type semiconductor layer 15 by an insulating film 18; a first element electrode 19 which is electrically connected to the n-electrode 16 and which is provided to extend in a first direction; and a second element electrode 20 which is electrically connected to the p-type semiconductor layer 15 and which is provided to extend in the first direction while being spaced apart from first element electrode 19. The thickness of the element substrate 11 is 100 μm or less.SELECTED DRAWING: Figure 1B

Description

[Technical field]

[0001] The present invention relates to a light-emitting element and a light-emitting device, and more particularly to a semiconductor light-emitting element such as a light-emitting diode (LED) and a light-emitting device in which the semiconductor light-emitting element is mounted. [Background technology]

[0002] Light emitting devices in which semiconductor light emitting elements are mounted are used in various lighting or display devices, etc. In particular, in recent years, there has been a demand for light emitting devices in which semiconductor light emitting elements are mounted to be thinner in order to achieve further space saving.

[0003] For example, Patent Document 1 discloses a light-emitting device including a mounting substrate having a base material and a wiring layer for external connection, and a light-emitting element provided on the upper surface of the mounting substrate and having both a first conductivity type (negative) and a second conductivity type (positive) electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2010-219324 Summary of the Invention [Problem to be solved by the invention]

[0005] However, a light-emitting device comprising a mounting board having a base material and a wiring layer for external connection, and a light-emitting element provided on the upper surface of the mounting board and having both electrodes of a first conductivity type (negative) and a second conductivity type (positive), has had reliability problems, for example, in that stress may be concentrated between the two electrodes, causing damage or deterioration of the semiconductor light-emitting element.

[0006] The present invention has been made in consideration of the above points, and aims to provide a semiconductor light-emitting element that is thin and yet has improved luminous flux when made into a light-emitting device, or a light-emitting device that is highly reliable and has improved luminous flux. [Means for solving the problem]

[0007] A semiconductor light emitting device according to one embodiment of the present invention comprises: a flat, light-transmitting element substrate having two main surfaces facing each other; a light emitting semiconductor layer formed on one main surface of the element substrate, the light emitting semiconductor layer being a laminate of an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer; an n-electrode connected to the n-type semiconductor layer through at least one hole reaching the n-type semiconductor layer and provided on the p-type semiconductor layer so as to be electrically isolated from the p-type semiconductor layer by an insulating film; a first element electrode electrically connected to the n-electrode and extending in a first direction; a second element electrode electrically connected to the p-type semiconductor layer and extending in the first direction while being spaced apart from the first element electrode; The element substrate has a thickness of 100 μm or less. [Brief description of the drawings]

[0008] [Figure 1A] 1 is a plan view showing the upper surface of a semiconductor light emitting device according to the present invention; [Figure 1B] 1B is a cross-sectional view of the semiconductor light-emitting element taken along line AA shown in FIG. 1A. [Figure 1C] 1B is a cross-sectional view of the semiconductor light-emitting element taken along line BB shown in FIG. 1A. [Figure 1D] 1B is a cross-sectional view of the semiconductor light-emitting element taken along line CC shown in FIG. 1A. [Figure 1E] 2 is a plan view showing the bottom surface of the semiconductor light emitting device of the present invention. FIG. [Figure 2A] FIG. 2 is a plan view showing the upper surface of the light emitting device of the present invention. [Figure 2B] 2B is a cross-sectional view of the light emitting device taken along line DD shown in FIG. 2A. [Figure 2C] FIG. 2 is a plan view showing the bottom surface of the light emitting device of the present invention. [Figure 2D] FIG. 2 is a plan view showing the upper surface of the light emitting device of the present invention, showing the covering member through which the light emitting device is viewed. [Diagram 3] FIG. 2 is a plan view showing the upper surface of the device substrate of the present invention. [Figure 4] 1 is a flowchart showing a method for manufacturing a light emitting device according to the present invention. [Figure 5A] 2 is a plan view showing the upper surface of the light emitting device according to the present invention at manufacturing step S1. FIG. [Figure 5B] 10 is a plan view showing the upper surface of the light emitting device according to the present invention at manufacturing step S2. [Figure 5C] 10 is a plan view showing the upper surface of the light emitting device according to the present invention at manufacturing step S3. FIG. [Figure 5D] 11 is a plan view showing the upper surface of the light emitting device according to the present invention at manufacturing step S4. FIG. [Figure 5E] 11 is a plan view showing the upper surface of the light emitting device according to the present invention at manufacturing step S5. FIG. [Figure 6A] FIG. 11 is a plan view showing the upper surface of the light emitting device according to embodiment 3, showing the covering member through which the light emitting device is seen. [Figure 6B] 13 is a diagram showing a wiring pattern of a circuit board 60 on which a light emitting device according to a third embodiment is mounted. [Figure 6C] 13 is a diagram showing a modified example of the wiring pattern of the circuit board 60 on which the light emitting device according to the third embodiment is mounted. [Figure 7] 11 is a plan view showing the upper surface of a device substrate of a light emitting device according to Embodiment 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the following, preferred embodiments of the present invention will be described, which may be modified and combined as appropriate. In the following description and the accompanying drawings, substantially the same or equivalent parts are denoted by the same reference numerals. The semiconductor light-emitting element will be described first, followed by the light-emitting device. [Embodiment 1]

[0010] The first embodiment is a semiconductor light-emitting element 10 used in the light-emitting device 30 shown in Fig. 2. Fig. 1A is a plan view showing the upper surface of the semiconductor light-emitting element 10 of the present invention. Fig. 1B is a cross-sectional view of the semiconductor light-emitting element 10 taken along line AA shown in Fig. 1A, Fig. 1C is a cross-sectional view of the semiconductor light-emitting element 10 taken along line BB shown in Fig. 1A, and Fig. 1D is a cross-sectional view of the semiconductor light-emitting element 10 taken along line CC shown in Fig. 1A. Fig. 1E is a plan view showing the lower surface of the semiconductor light-emitting element 10 of the present invention.

[0011] In FIG. 1A, holes 12A in the light emitting semiconductor layer 12, which will be described later, are shown by dashed lines in order to clarify the positional relationship of the holes 12A.

[0012] In the description of the semiconductor light emitting device 10, the direction in which the light emitting semiconductor layer 12 is provided on the element substrate 11 is referred to as the upper side, and the opposite direction is referred to as the lower side.

[0013] 1A to 1E, the semiconductor light emitting element 10 has a rectangular flat-plate-shaped element substrate 11 having two parallel main surfaces, and a light emitting semiconductor layer 12 in which semiconductor crystals are laminated is provided on the upper surface of the element substrate 11. Two electrodes, an n-electrode 16 and a p-electrode 17, which are partially insulated by an insulating film 18, are arranged on the upper surface of the light emitting semiconductor layer 12, and a rectangular first element electrode 19 and a second element electrode 20 of approximately equal size are provided on the upper surfaces of the two electrodes and extend in one direction (the left-right direction in FIG. 1A) and are provided in parallel so as to approximately cover the upper surface of the semiconductor light emitting element 10. That is, the main light emitting surface of the semiconductor light emitting element 10 of this embodiment is the lower surface 11B side of the element substrate 11.

[0014] (element substrate) 1B, the element substrate 11 is a rectangular flat plate having an upper surface 11A as a first main surface and a lower surface (back surface) 11B as a second main surface that face each other in parallel. The element substrate 11 is translucent to transmit light emitted from the light emitting semiconductor layer 12. The element substrate 11 also functions as a body (support) of the semiconductor light emitting element 10.

[0015] As the element substrate 11, sapphire (Al2O3) single crystal is used. The bending strength of sapphire single crystal is 690 MPa, and even if the element substrate 11 is thinned, it has high strength. In this embodiment, the thickness Tsub of the element substrate 11 is thinned to 100 μm to reduce the thickness of the entire semiconductor light emitting element 10. However, if it is too thin, the function as a body is impaired, so a range of 40 μm to 100 μm is preferable. For example, if it is less than 40 μm, the occurrence of defects such as non-lighting during the manufacture or use of the semiconductor light emitting element 10 and the light emitting device 30 increases. Also, if it exceeds 100 μm, the strength of the body can be improved, but the light emitting device 30 cannot be thinned. As the element substrate 11, aluminum nitride (AlN) single crystal, silicon nitride (SiC) single crystal, gallium nitride (GaN) single crystal, etc. can also be used.

[0016] The lower surface 11B of the element substrate 11 may be provided with a rough surface layer for improving light extraction efficiency and / or an anti-reflection coating (AR film).

[0017] (Light emitting semiconductor layer) 1B, the light-emitting semiconductor layer 12 is a semiconductor crystal laminated structure having a total thickness Tepi of 3 μm to 5 μm, in which an n-type semiconductor layer 13 having an n-type semiconductor layer as a main conductivity type, a light-emitting layer 14 including a quantum well layer structure, and a p-type semiconductor layer 15 having a p-type semiconductor layer as a main conductivity type are laminated in this order. The light-emitting semiconductor layer 12 is a crystal growth layer grown using the element substrate 11 as a growth substrate, and is supported integrally with the element substrate 11.

[0018] The n-type semiconductor layer 13 of the light emitting semiconductor layer 12 has the same size as the element substrate 11 when viewed from above. The light emitting layer 14 and the p-type semiconductor layer 15 are slightly smaller than the outer shape of the n-type semiconductor layer 13. In other words, the exposed portion of the n-type semiconductor layer 13 surrounds the light emitting layer 14 and the p-type semiconductor layer 15 all around in a frame shape.

[0019] 1A, the light emitting semiconductor layer 12 has three holes 12A extending from the upper surface of the p-type semiconductor layer 15 to the n-type semiconductor layer 13. The three holes 12A are arranged in a straight line at equal intervals, and the central hole is disposed at the center X1 of the light emitting semiconductor layer 12. The three holes 12A are arranged parallel to a pair of parallel sides of the element substrate 11.

[0020] In this embodiment, the number of holes 12A is three, but it may be one or two, or it may be four or more. Also, they may be arranged in two rows in parallel.

[0021] The light emitting semiconductor layer 12 is made of a gallium nitride (GaN) compound semiconductor and emits blue light. The p-type semiconductor layer 15 or the n-type semiconductor layer 13 may include layers such as an undoped layer, a strained-layer superlattice (SLS) layer, an electron blocking layer (EBL), and a contact layer in addition to a layer doped with an impurity exhibiting a main conductivity type.

[0022] (n electrode) 1B, n-electrode 16 is provided via first insulating film 18A on the upper surface of first p-electrode 17A on the left side partitioned by linearly arranged holes 12A. A part of n-electrode 16 passes through hole 12A whose wall surface is insulated by first insulating film 18A and is electrically connected to n-type semiconductor layer 13.

[0023] The n-electrode 16 is formed by laminating titanium (Ti) and gold (Au) in this order. Hereinafter, layers laminated in order will be referred to as Ti / Au. The n-electrode 16 can also be made of Ti / aluminum (Al), Ti / Al / platinum (Pt) / Au, Ti / Pt / Au, Ti / rhodium (Rh) / Au, or the like.

[0024] (p electrode) 1B, p electrode 17 is composed of a first p electrode 17A and a second p electrode 17B. First p electrode 17A is provided on substantially the entire surface of p-type semiconductor layer 15. Second p electrode 17B is provided on the upper surface of first p electrode 17A on the right side partitioned by linearly arranged holes 12A.

[0025] The first p electrode 17A is formed by laminating nickel (Ni) / Au. The first p electrode 17A may also be made of ITO (Indium Tin Oxide), Ni / Pt / Au, Ni / palladium (Pd) / Au, Ni / silver (Ag) / Pt / Au, Ni / Pt / Al / Pt / Au, or the like.

[0026] Second p-electrode 17B is formed by stacking Ti / Au. As with n-electrode 16, second p-electrode 17B can also be made of Ti / Al, Ti / Al / Pt / Au, Ti / Pt / Au, Ti / Rh / Au, or the like.

[0027] (insulating film) As shown in FIG. 1B, the insulating film 18 is made up of a first insulating film 18A and a second insulating film 18B.

[0028] The first insulating film 18A covers, protects, and insulates the n-type semiconductor layer 13, the light emitting layer 14, and the p-type semiconductor layer 15. In addition, the first insulating film 18A covers, protects, and insulates a part of the side and bottom surface of the first p-electrode 17A in contact with the p-type semiconductor layer 15.

[0029] The second insulating film 18B covers, protects, and insulates the first insulating film 18A, the n-electrode 16 except for a portion, and the second p-electrode 17B.

[0030] Silicon dioxide (SiO2) is used as the insulating film 18. Note that insulating film 18 may also be made of insulating metal oxides such as titanium dioxide (TiO2), hafnium oxide (HfO2), and alumina (Al2O3).

[0031] (Element electrode) The first element electrode 19 and the second element electrode 20 (hereinafter, when there is no need to distinguish between them, they will be referred to as element electrodes) are provided on the upper surface of the semiconductor light emitting element 10, as shown in Figures 1A and 1B. The element electrodes 19, 20 are rectangular with approximately the same size, having a pair of parallel long sides and another pair of parallel short sides, and are provided in parallel, spaced apart by three holes 12A arranged in a straight line. The element electrodes are provided on the inside, away from the outer periphery of the semiconductor light emitting element 10. The two element electrodes 19, 20 are bonding electrodes that electrically bond the semiconductor light emitting element 10 to external wiring. Such a semiconductor light emitting element 10 is a flip-chip bonding type light emitting element that does not require wire bonding.

[0032] The first element electrode 19 (cathode) is connected to the n-type semiconductor layer 13 via the n-electrode 16, and the second element electrode 20 (anode) is connected to the p-type semiconductor layer 15 via the p-electrode 17. Thus, by applying a voltage to the first element electrode 19 and the second element electrode 20, electricity can be passed through the light emitting semiconductor layer 12, causing the semiconductor light emitting element 10 to emit light.

[0033] The element electrodes are made of Ni / Au, but may also be made of other metals with good conductivity, such as Ti / Au or Ti / Ni / Au.

[0034] [Comparative form 1] Next, a description will be given of Comparative Example 1. Comparative Example 1 is a semiconductor light emitting device in which the thickness Tsub of the element substrate 11 of Embodiment 1 is increased from 100 μm to 200 μm. Note that, other than the thickness of the element substrate, the semiconductor light emitting device is the same as the semiconductor light emitting device 10 of Embodiment 1.

[0035] (Light output comparison) The semiconductor light emitting device 10 of the first embodiment and the semiconductor light emitting device of the first comparative embodiment were bonded to a circuit board via a gold-tin bonding member, and the light output was compared by passing electricity through each semiconductor light emitting device. As a result, when the light output of the first comparative embodiment was taken as 100%, the light output of the first embodiment was 98%. In other words, the light output of the semiconductor light emitting device 10 of the first embodiment was 2% lower than the light output of the semiconductor light emitting device of the first comparative embodiment.

[0036] The decrease in light output is due to the reduction in the area of ​​the light emitting surface caused by thinning the element substrate 11. Therefore, as the element substrate 11 is thinned to 70 μm and then 40 μm, the light output further decreases. At the same time, the mechanical strength of the semiconductor light emitting element 10 also decreases.

[0037] As described above, the semiconductor light emitting device 10 of the first embodiment can be made thin, even though this involves a decrease in optical output and mechanical strength at the stand-alone stage.

[0038] (Method of manufacturing semiconductor light emitting device) Next, a method for manufacturing the semiconductor light emitting device 10 of the first embodiment will be described.

[0039] First, an element substrate 11 is prepared having a light emitting semiconductor layer 12 in which a gallium nitride-based n-type semiconductor layer 13, a light emitting layer 14 and a p-type semiconductor layer 15 are epitaxially grown on one surface of a sapphire single crystal substrate (SD1).

[0040] A resist mask is formed on the portion of the element substrate 11 with the light emitting semiconductor layer 12 that will become the light emitting region, and etching is performed by RIE (Reactive Ion Etching) until the n-type semiconductor layer 13 is exposed in the portion other than the resist mask. Thereafter, the resist mask is removed to form a light emitting region having a hole 12A (SD2).

[0041] A resist mask is formed on the upper surface of the p-type semiconductor layer 15 in the light-emitting region, exposing the portion that will become the first p electrode 17A, and Ni and Au are evaporated in this order as the first p electrode 17A using an EB (electron beam) evaporation device. Thereafter, the resist mask is removed to form the first p electrode 17A (SD3).

[0042] A sputtering device is used to form a SiO2 film as an insulating film on the entire surface of the element substrate on which the first p electrode 17A is formed. Next, a resist mask is formed on the bottom of the hole 12A and on the area other than where the second p electrode 17B is to be formed, and the insulating film on the bottom of the hole 12A and the area where the second p electrode 17B is to be formed is etched away with a hydrofluoric acid buffer solution to form a first insulating film 18A (SD4).

[0043] A resist mask is formed on areas other than those that will become n-electrode 16 and second p-electrode 17B, and Ti and Au are evaporated in this order using an EB evaporation device to form n-electrode 16 and second p-electrode 17B. The resist mask is then removed to form n-electrode 16 and second p-electrode 17B (SD5).

[0044] A sputtering device is used to form a SiO2 film as an insulating film on the entire surface of the element substrate on which the n-electrode 16 and the second p-electrode 17B are formed. Next, a resist mask is formed on the portions other than where the first element electrode 19 and the second element electrode 20 are to be formed, and the insulating film on the portions where the n-electrode 16 and the second p-electrode 17B are to be formed is etched away with a hydrofluoric acid buffer solution to form a second insulating film 18B (SD6).

[0045] A resist mask is formed on areas other than those that will become the first element electrode 19 and the second element electrode 20, and Ti and Au are evaporated in this order as element electrodes using an EB evaporation system. Thereafter, the resist mask is removed to form the first element electrode 19 and the second element electrode 20 (SD7).

[0046] Next, the sapphire single crystal substrate of the element substrate on which the first element electrode 19 and the second element electrode 20 are formed is thinned to 100 μm using a grinding and polishing device to form the element substrate 11 (SD8). To thin the element substrate 11 to 70 μm or 40 μm, the amount of grinding and polishing of the sapphire single crystal substrate in this process can be increased. To form the semiconductor light emitting device of Comparative Form 1 with a sapphire substrate 11 of 200 μm, the amount of grinding and polishing can be reduced.

[0047] Laser scribing is performed along the outline of each semiconductor light emitting element 10 from the front side (rear side) of the element substrate 11, and the semiconductor light emitting element 10 is formed by dividing it into individual units (SD9).

[0048] [Embodiment 2] Next, a light emitting device 30 of embodiment 2 will be described. Fig. 2A is a plan view showing the upper surface of the light emitting device 30 of the present invention. Fig. 2B is a cross-sectional view of the light emitting device 30 taken along line DD shown in Fig. 2A, and Fig. 2C is a plan view showing the lower surface of the light emitting device 30 of the present invention. Fig. 2D is a plan view showing the upper surface of the light emitting device 30 of the present invention, showing the state where the covering member 44 is seen through (removed).

[0049] Fig. 3 is a plan view showing the upper surface of the device substrate 31. In Fig. 2C, in order to clarify the positional relationship among the first element electrode 19 and the second element electrode 20, the first conductive via 35 and the second conductive via 36, ​​and the first mounting electrode 37 and the second mounting electrode 38, which will be described later, the first conductive via 35 and the second conductive via 36, ​​and the first element electrode 19 and the second element electrode 20 are shown by dashed lines.

[0050] Furthermore, in order to clarify the positional relationship between the first element electrode 19 and the second element electrode 20 and the first mounting electrode 37 and the second mounting electrode 38, the first mounting electrode 37 and the second mounting electrode 38 are shown by dashed lines in Figure 2D, and the first element electrode 19 and the second element electrode 20 and the first mounting electrode 37 and the second mounting electrode 38 are shown by dashed lines in Figure 3.

[0051] In the description of the light emitting device 30, the direction in which the semiconductor light emitting element 10 is provided on the device substrate 31 is referred to as the upper side, and the opposite direction is referred to as the lower side. Note that XYZ coordinates are added to each drawing.

[0052] 2A and 2B, the light emitting device 30 has the semiconductor light emitting element 10 and protective element 39 bonded to the upper surface (+Z direction) of a rectangular, flat device substrate 31 via a bonding member 41. A phosphor plate 43 is bonded to the upper surface of the semiconductor light emitting element 10 via a light-transmitting adhesive member 42. An upper surface 32A of the device substrate 31 and the side surfaces of the semiconductor light emitting element 10 and phosphor plate 43 are covered with a light-shielding covering member 44. Thus, the exposed upper surface of the phosphor plate 43 serves as the light emitting surface of the light emitting device 30.

[0053] (Device board) As shown in Fig. 2B to Fig. 2D and Fig. 3, the device substrate 31 is a rectangular flat plate having a pair of long sides (sides in the X-axis direction) that are parallel and opposed to each other in a top view, and another pair of short sides (sides in the Y-axis direction) that are perpendicular to the pair of long sides and parallel and opposed to each other. The device substrate 31 has a base 32 having an upper surface 32A that is a first main surface and a lower surface 32B that is a second main surface that are opposed to each other, and a first wiring electrode 33 and a second wiring electrode 34 are provided on the upper surface 32A of the base 32, and a first mounting electrode 37 and a second mounting electrode 38 are provided on the lower surface 32B. In addition, a first conductive via 35 and a second conductive via 36 that vertically penetrate the base 32 are provided. Hereinafter, when there is no distinction between the first wiring electrode 33 and the second wiring electrode 34, they will be referred to as wiring electrodes, when there is no distinction between the first mounting electrode 37 and the second mounting electrode 38, they will be referred to as mounting electrodes, and when there is no distinction between the first conductive via 35 and the second conductive via 36, ​​they will be referred to as conductive vias.

[0054] An aluminum nitride (AlN) ceramic substrate having a thickness Tbase of 70 μm is used as the base 32. Aluminum nitride (AlN) ceramic is an insulating ceramic with excellent thermal conductivity and bending strength, with a thermal conductivity of 180 to 220 W / mK and a bending strength of 300 to 350 MPa. The thickness of the base 32 is preferably thin from the viewpoint of making the light emitting device 30 thinner, and taking into account the strength of the base, the thickness is preferably 30 μm to 120 μm. Note that silicon nitride (Si3N4) ceramics and the like can also be used as the base 32.

[0055] As shown in FIG. 3, the first wiring electrode 33 (cathode) is provided on one surface (the surface in the +Y direction in FIG. 3) divided by a line segment LX2 parallel to the long side of the device substrate 31 passing through the midpoint X2 of the device substrate 31. The first wiring electrode 33 has a first land 33A and a first element mounting region 33B. The first element mounting region 33B is rectangular and includes the element electrode 19 (cathode) of the semiconductor light emitting element 10, and is provided in the center of the device substrate 31 with its long side aligned along the line segment LX2. The first land 33A is provided at an end of the one surface separated from the first element mounting region 33B. The first element mounting region 33B and the first land 33A are connected by a first band portion 33C parallel to the line segment LX2.

[0056] The second wiring electrode 34 (anode) is provided on the other surface (surface in the -Y direction in FIG. 3) divided by a line segment LX2 parallel to the long side of the device substrate 31 passing through the midpoint X2 of the device substrate 31. The second wiring electrode 34 has a second land 34A, a second element mounting region 34B, and a protective element mounting region 34C. The second element mounting region 34B is rectangular in shape to include the element electrode 20 (anode) of the semiconductor light emitting element 10, and is provided in the center of the device substrate 31 with its long side aligned along the line segment LX2. The second land 34A is provided at the end of the other surface that does not face the first land 33A. The protective element mounting region 34C is provided at the end of the other surface that faces the first land 33A. The second element mounting region 34B, the second land 34A, and the protection element mounting region 34C are connected by a second belt portion 34D that is parallel to the line segment LX2.

[0057] The short sides of the first element mounting region 33B of the first wiring electrode 33 and the second element mounting region 34B of the second wiring electrode 34 are aligned in a top view (XY plane). In other words, the outer edge of the first element mounting region 33B and the second element mounting region 34B combined forms a rectangle and is large enough to encompass the semiconductor light emitting element 10.

[0058] The first mounting electrode 37 (cathode) is provided on one surface (the surface in the +X direction in FIG. 2C) separated by a line segment LY2 parallel to the short side of the device substrate 31 and passing through the midpoint X2 of the device substrate 31. The first mounting electrode 37 has a rectangular shape that substantially covers one surface of the lower surface 32B of the base 32, and has a cathode mark (cut corner portion) provided at one corner.

[0059] The second mounting electrode 38 (anode) is provided on the other surface (the surface in the -X direction in FIG. 2C) separated by a line segment LY2 that is parallel to the short side of the device substrate 31 and passes through the midpoint X2 of the device substrate 31. The second mounting electrode 38 has a rectangular shape that substantially covers the other surface of the lower surface 32B of the base 32.

[0060] As described above, the first element mounting region 33B of the first wiring electrode 33 and the second element mounting region 34B of the second wiring electrode 34 are separated by the wiring electrode spacing band 48 along the line segment LX2. That is, the element electrodes 19 and 20 are spaced apart from each other in the extension direction (Y-axis direction) of the line segment LY2 perpendicular to the line segment LX2. Also, the first mounting electrode 37 and the second mounting electrode 38 are spaced apart from each other by the mounting electrode spacing band 47 along the line segment LY2 perpendicular to the wiring electrode spacing band 48. That is, the first mounting electrode 37 and the second mounting electrode 38 are spaced apart from each other in the extension direction (X-axis direction) of the line segment LX2. In this way, by orthogonally arranging the wiring electrode spacing bands 48 of the element mounting areas 33B, 34B and the mounting electrode spacing bands 47 of the mounting electrodes 37, 38, it is possible to prevent the device substrate 31 from bending even if it is made thin when joining the semiconductor light emitting element 10 and mounting the light emitting device 30 to the circuit substrate.

[0061] The first conductive via 35 (cathode) vertically penetrates the base 32 between the first land 33A of the first wiring electrode 33 and the first mounting electrode 37, and electrically connects them both.

[0062] The second conductive via 36 (anode) vertically penetrates the base 32 between the second land 34A of the second wiring electrode 34 and the second mounting electrode 38, and electrically connects the two together.

[0063] Since the surfaces of the wiring electrodes 33, 34 and the mounting electrodes 37, 38 to which the conductive vias 35, 36 are connected become uneven, impairing the smoothness of the electrode surfaces, the conductive vias 35, 36 are provided in areas other than the first element mounting area 33B of the first wiring electrode 33 and the second element mounting area 34B of the second wiring electrode 34.

[0064] The first wiring electrode 33, the second wiring electrode 34, the first mounting electrode 37, the second mounting electrode 38, the first conductive via 35, and the second conductive via 36 are made of a metal mainly made of copper (Cu). The wiring electrodes and mounting electrodes have their surfaces plated with a Ni / Au layer. Tungsten (W) or the like can also be used as the main metal of the wiring electrodes, mounting electrodes, and conductive vias.

[0065] (Light emitting element) The semiconductor light emitting element 10 is a flip chip having a first element electrode 19 and a second element electrode 20 of approximately equal size and rectangular shape on the surface facing the element substrate 11, which is the light emitting surface. In addition, the first element electrode 19 and the second element electrode 20 of the semiconductor light emitting element 10 are connected to the first element mounting region 33B and the second element mounting region 34B via a bonding member 41. The semiconductor light emitting element 10 having such element electrodes 19 and 20 has excellent self-alignment to the element mounting regions 33B and 34B of the device substrate 31 and has low residual stress in bonding. In other words, even if the element substrate 11 or the device substrate 31 is thin, bonding can be performed with a high yield. The size of the semiconductor light emitting element 10 used in this embodiment is a square shape with one side of approximately 1000 μm and a thickness of approximately 100 μm (thickness of the semiconductor light emitting element 10 ≒ thickness of the element substrate 11). In consideration of ease of handling during the manufacturing process of the thin semiconductor light emitting element 10, it is preferable that one side (line segment LX, line segment LY) is 600 μm to 1600 μm.

[0066] (Protection element) 2B and 2D, the protective element 39 is bonded to the protective element mounting region 34C of the device substrate 31 via a bonding member 41. An upper electrode of the protective element 39 is electrically connected to the first land 33A by a conductive wire 40. The protective element 39 is connected in parallel with the semiconductor light emitting element 10 with opposite polarity to prevent damage to the semiconductor light emitting element 10 due to static electricity or the like. The top of the wire 40 of the protective element 39 is lower than the combined height (thickness) of the semiconductor light emitting element 10 and the phosphor plate 43.

[0067] Although a Zener diode is used as the protection element 39 in this embodiment, a capacitor, a varistor, or the like may also be used as the protection element 39 in addition to the Zener diode.

[0068] (Jointing material) A gold-tin (Au-20wt%Sn) alloy is used as the bonding member 41. Gold-tin cream solder is used to form the gold-tin alloy. The flux contained in the gold-tin cream solder evaporates when the semiconductor light-emitting element 10 and the protective element 39 are bonded to the device substrate 31. The surfaces of the element mounting areas 33B, 34B to which the semiconductor light-emitting element 10 is bonded are smooth, and the bonding member 41 is formed with a uniform thickness in the areas where the element electrodes 19, 20 of the semiconductor light-emitting element 10 overlap with the element mounting areas 33B, 34B. This can reduce the stress acting on the thinned semiconductor light-emitting element 10 during bonding, and can prevent damage to the semiconductor light-emitting element 10.

[0069] (Phosphor plate) The phosphor plate 43 as a wavelength conversion member has a flat plate shape with substantially the same size as the light output surface of the semiconductor light emitting element 10 in a top view. The phosphor plate 43 is a ceramic phosphor in which cerium-activated yttrium aluminum garnet (YAG:Ce) phosphor particles are contained in an alumina base material. As shown in FIG. 2B, the phosphor plate 43 is bonded to the upper surface (+Z direction) of the element substrate 11 of the semiconductor light emitting element 10 via an adhesive member 42 made of a translucent silicone resin. The phosphor plate 43 absorbs a part or all of the blue light (primary light) emitted from the semiconductor light emitting element 10, and emits greenish yellow light (secondary light) whose wavelength is longer than that of the primary light. As a result, white light or greenish yellow light in which the blue light (primary light) and the greenish yellow (secondary light) are mixed is emitted from the upper surface of the phosphor plate 43 of the light emitting device 30.

[0070] The phosphor plate 43 may be smaller or larger than the light output surface of the semiconductor light emitting element 10. In addition, a concave-convex structure for reducing reflectance, a light-transmitting protective film for protecting the surface, a dielectric multilayer film for controlling directional characteristics, or the like may be provided on the light input surface (lower surface) or the light output surface (upper surface) of the phosphor plate 43. In addition, a reflective dielectric multilayer film or a white ceramic film may be provided on the side surface.

[0071] The base material of the phosphor plate 43 may be a transparent inorganic material such as ceramic or glass, or a transparent resin material. The light conversion particles are not limited to cerium-activated yttrium aluminum garnet (YAG:Ce) phosphor, but may be cerium-activated lutetium aluminum garnet (LuAG:Ce) phosphor, europium and / or cerium-activated orthosilicate ((Ba,Sr,Ca)SiO4:Eu,Ce) phosphor, cerium-activated terbium aluminum garnet (TAG:Ce), europium-activated α-sialon phosphor (α-SiAlON:Eu), europium-activated β-sialon phosphor (β-SiAlON:Eu), manganese-activated potassium potassium fluorosilicate (KFS:Mn), or the like. Different types of light conversion particles may be appropriately selected and used depending on the wavelength of the excitation light, the desired color tone, and the like.

[0072] (Covering material) As shown in Figs. 2A and 2B, the covering member 44 starts from the outer periphery of the upper surface of the phosphor plate 43 and extends outward from the phosphor plate 43 while exposing the upper surface of the phosphor plate 43. The covering member 44 covers the upper surface of the device substrate 31, as well as the side surfaces of the joining member 41, the semiconductor light emitting element 10, the adhesive member 42, and the phosphor plate 43. That is, the semiconductor light emitting element 10 and the protective element 39 are sealed by the covering member 44. The upper surface of the phosphor plate 43 is the light emitting surface of the light emitting device 30. In this embodiment, since the element substrate 11 of the semiconductor light emitting element 10 is thin, even if the device substrate 31 of the light emitting device 30 is thin, the thickness of the covering member 44 is also thin, so that the occurrence of warping of the light emitting device 30 due to the expansion and contraction of the covering member 44 can be suppressed.

[0073] A white resin in which reflective titanium oxide (TiO2) particles are dispersed in a light-transmitting silicone resin medium is used as the covering member 44. Epoxy resin, acrylic resin, polycarbonate resin, polystyrene resin, etc. can also be used as the light-transmitting medium. Also, a mixture of ceramic particles of alumina (Al2O3) and zirconia (ZrO2) can also be used as the reflective particles.

[0074] (Mounting on a circuit board) In the light emitting device 30 of the second embodiment, each of the first mounting electrode 37 and the second mounting electrode 38 is mounted on the circuit board via solder. The wiring electrode spacing strips 48 of the first element mounting region 33B and the second element mounting region 34B of the light emitting device 30 are perpendicular to the mounting electrode spacing strips 47 of the first mounting electrode 37 and the second mounting electrode 38. Therefore, when mounting the light emitting device 30 on the circuit board, stress that bends the straight line portion in which the three hole portions 12A of the semiconductor light emitting element 10 are aligned is suppressed. As a result, even if the element substrate 11 and the device substrate 31 are thin, defects such as a short circuit of the light emitting device 30 can be prevented, and the reliability of the light emitting device 30 can be improved.

[0075] [Comparative form 2] Next, a description will be given of a light emitting device of Comparative Example 2. The light emitting device of Comparative Example 2 is a light emitting device in which the thickness of the element substrate 11 of the semiconductor light emitting element 10 of the light emitting device 30 of Embodiment 2 is changed from 100 μm to 200 μm, and other than that, it is the same as Embodiment 2.

[0076] (Comparison of light output from light emitting devices) The light emitting device 30 of the second embodiment and the light emitting device of the comparative embodiment 2 were soldered to a circuit board, and the light output was compared by passing electricity through each light emitting device. As a result, when the light output of the comparative embodiment 2 was 100%, the light output of the second embodiment was 108%. That is, the light output of the light emitting device 30 of the second embodiment increased by 8%. This is considered to be due to a decrease in the contact area between the element substrate 11 of the semiconductor light emitting element 10 and the covering member 44. Similarly, the light output increases when the element substrate 11 is thinned to 70 μm and 40 μm. Thus, the semiconductor light emitting element 10 of the first embodiment used in the light emitting device 30 of the second embodiment has a tendency to decrease in light output when used alone, but the light emitting device 30 of the second embodiment provides high light output (luminous flux) characteristics as the light emitting device 30. In addition, by making the light emitting device 30 thinner, it is possible to suppress light leakage from the side surface of the light emitting device 30, and to increase the light output from the light emitting surface (upper surface of the phosphor plate 43) of the light emitting device 30.

[0077] As described above, according to the present invention, it is possible to provide a semiconductor light-emitting element 10 that is thin and has improved luminous flux when made into a light-emitting device 30, or a light-emitting device 30 that is highly reliable and has improved luminous flux.

[0078] (Method of manufacturing a light emitting device) A method for manufacturing the light emitting device 30 of the second embodiment will be described in detail below with reference to a flowchart and the drawings. Fig. 4 is a flowchart showing the method for manufacturing the light emitting device 30. Figs. 5A to 5E are top views showing each step.

[0079] (S1) Preparation of device board As the device substrate 31, a substrate was prepared in which a first wiring electrode 33, a second wiring electrode 34, a first conductive via 35, a second conductive via 36, ​​a first mounting electrode 37, and a second mounting electrode 38 were provided on a base 32, and device substrates 31 for a plurality of light emitting devices were integrated (FIG. 5A). In the following explanation, (S2) to (S4) will be explained with reference to the integrated substrate. An outer peripheral frame is provided around the periphery of the integrated substrate. Also, the portion surrounded by the thick line in the figure is one unit of device substrate 31.

[0080] (S2) Element mounting process On the first wiring electrode 33 and the second wiring electrode 34 on which the semiconductor light emitting element 10 and the protective element 39 were mounted, gold-tin (Au-Sn) solder paste was applied as a bonding member 41. Next, the semiconductor light emitting element 10 and the protective element 39 were placed on the gold-tin solder paste.

[0081] Next, the gold-tin solder paste was heated to 300° C. in a reflow furnace to melt and solidify, and the semiconductor light-emitting element 10 was mounted on the first wiring electrode 33 and the second wiring electrode 34. At the same time, the protective element 39 was also mounted on the second wiring electrode 34. Thereafter, the upper electrode of the protective element 39 and the first wiring electrode 33 were electrically connected by a wire 40 (FIG. 5B).

[0082] (S3) Phosphor plate bonding process Silicone resin, which is a light-transmitting adhesive, was applied to the upper surface of the semiconductor light-emitting element 10 as the adhesive member 42. Next, phosphor plate 43 was placed on the semiconductor light-emitting element 10. The silicone resin was temporarily cured by heating at 170° C. for 10 minutes, and phosphor plate 43 was adhered to the semiconductor light-emitting element 10 ( FIG. 5C ).

[0083] (S4) Covering member formation process A frame 45 was formed on the outer periphery of a plurality of device substrates 31. A coating member 44 made of silicone resin mixed with titanium oxide particles was filled inside the frame 45 up to a height where it contacted the outer periphery of the upper surface of the phosphor plate 43. The silicone resin was then cured by heating at 100°C for 30 minutes and at 150°C for 1 hour. At this time, the adhesive member 42 was also fully cured (FIG. 5D).

[0084] (S5) Singulation process The substrate was cut into individual pieces each comprising a light emitting device 30 using a dicing blade 46. Through the above steps, the light emitting device 30 was manufactured (FIG. 5E).

[0085] [Embodiment 3] Next, a light emitting device 50 according to a third embodiment will be described. Note that descriptions of the same configuration as that of the light emitting device 30 according to the second embodiment of the present invention will be omitted as appropriate. Fig. 6A is a plan view showing the upper surface of the light emitting device 50 according to the third embodiment, showing the state in which the covering member 44 is seen through (removed). Fig. 6B is a diagram showing the wiring pattern of a circuit board 60 on which the light emitting device 50 is mounted, and Fig. 6C is a diagram showing a modified example of the wiring pattern of the circuit board 60 on which the light emitting device 50 is mounted.

[0086] Fig. 7 is a plan view showing the upper surface of the device substrate 31 of the light emitting device 50 of the third embodiment. In Fig. 6A, the first conductive via 35 and the second conductive via 36 and the first mounting electrode 37 and the second mounting electrode 38 are shown by dashed lines in order to clarify the positional relationship between the first element electrode 19 and the second element electrode 20, the first conductive via 35 and the second conductive via 36, ​​and the first mounting electrode 37 and the second mounting electrode 38. Furthermore, in Fig. 7, the first conductive via 35 and the second conductive via 36 and the first mounting electrode 37 and the second mounting electrode 38 are shown by dashed lines in order to clarify the positional relationship between the first element electrode 19 and the second element electrode 20, the first conductive via 35 and the second conductive via 36, ​​and the first mounting electrode 37 and the second mounting electrode 38.

[0087] As shown in Fig. 6A, the light emitting device 50 of the third embodiment is a multi-unit (here, two units) light emitting device having two adjacent light emitting devices 30. The light emitting device 50 is configured such that two units of the light emitting device 30 of the second embodiment are coupled in parallel on a device substrate 31. Therefore, if the wiring pattern of the circuit substrate 60 is provided as shown in Fig. 6B, each light emitting element (light emitting region) of the light emitting device 50 can be driven individually.

[0088] In this way, by driving the two light emitting devices 30 in parallel, it is possible to individually light up the semiconductor light emitting elements 10 of each light emitting device 30. Therefore, for example, by making the wavelength conversion characteristics of the phosphor plates 43 of the light emitting devices 30 different from each other, it is possible to emit light of multiple colors from one light emitting device.

[0089] [Modification of the third embodiment] Next, in a modification of the light emitting device 50 of the third embodiment, a pair of an anode and a cathode are connected in series in the wiring pattern of the circuit board 60 as shown in Fig. 6C. In this way, by driving two light emitting devices 30 in series, the semiconductor light emitting elements 10 of each light emitting device 30 can be turned on simultaneously. This can further improve the luminous flux of the light emitting device.

[0090] In this embodiment, the number of light emitting devices 30 included in the multiple unit type light emitting device 50 is two, but it may be three or more. Also, as shown in Fig. 6A, in this embodiment, the two light emitting devices 30 have an individual phosphor plate 43 for each semiconductor light emitting element 10, but one phosphor plate 43 may be provided for multiple semiconductor light emitting elements 10.

[0091] As described above, according to the present invention, it is possible to provide a semiconductor light emitting element or light emitting device that is thin and has high reliability and improved luminous flux. [Explanation of symbols]

[0092] 10 Semiconductor light emitting device 11 Element substrate 12 Light-emitting semiconductor layer 13 n-type semiconductor layer 14 Emitting layer 15 p-type semiconductor layer 16n electrode 17p electrode 18 Insulating film 19 First element electrode 20 Second element electrode 30 Light emitting device 31 Device board 32 Base 33 1st wiring electrode 34 2nd wiring electrode 35 First conductive via 36 Second conductive via 37 First mounting electrode 38 Second mounting electrode 39 Protection elements 40 Wire 41 Joint materials 42 Adhesive materials 43 Phosphor plate 44 Covering material 45 Frame 46 Dicing Blade 47 Mounting electrode separation band 48 Wiring electrode separation band 50 Light emitting device 60 Circuit Board

Claims

1. a flat light-transmitting element substrate having two main surfaces opposed to each other; a light emitting semiconductor layer formed on one main surface of the element substrate, the light emitting semiconductor layer being a laminate of an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer; an n-electrode connected to the n-type semiconductor layer through at least one hole reaching the n-type semiconductor layer and provided on the p-type semiconductor layer so as to be electrically isolated from the p-type semiconductor layer by an insulating film; a first element electrode electrically connected to the n-electrode and extending in a first direction; a second element electrode electrically connected to the p-type semiconductor layer and extending in the first direction while being spaced apart from the first element electrode; The semiconductor light emitting device, wherein the thickness of the element substrate is 100 μm or less.

2. The semiconductor light emitting device according to claim 1 , wherein the thickness of the element substrate is 40 μm or more.

3. 2. The semiconductor light-emitting device according to claim 1, wherein the light-emitting semiconductor layer has a thickness of 3 to 5 μm.

4. the light emitting semiconductor layer has three or more holes, The semiconductor light emitting device according to claim 1 , wherein the plurality of holes are arranged in a straight line at equal intervals.

5. A semiconductor light emitting device according to claim 1 , a device substrate including a base formed in a flat plate shape having two planes facing each other, a first wiring electrode and a second wiring electrode provided on one of the planes, a first mounting electrode provided on the other plane and connected to the first wiring electrode by a first conductive via that penetrates the base, and a second mounting electrode provided on the other plane and connected to the second wiring electrode by a second conductive via that penetrates the base, and the semiconductor light emitting element is bonded onto the first wiring electrode and the second wiring electrode via a bonding member; the first element electrode and the second element electrode are arranged to be spaced apart from each other in a second direction perpendicular to the first direction, The light emitting device, wherein the first mounting electrode and the second mounting electrode are disposed apart from each other in the first direction.

6. the first element electrode and the second element electrode are spaced apart from a midpoint of the device substrate in the second direction, The light emitting device according to claim 5 , wherein the first mounting electrode and the second mounting electrode are spaced apart from a midpoint of the device substrate in the first direction.

7. the first wiring electrode has a first element mounting region in which the first element electrode is mounted and a first land in which the first conductive via is disposed, the second wiring electrode has a second element mounting region in which the second element electrode is mounted and a second land in which the second conductive via is disposed, The light emitting device according to claim 5 , wherein the first land and the second land are disposed spaced apart from the first element mounting region and the second element mounting region, respectively, in the first direction.

8. the element substrate is made of single crystal sapphire, 6. The light emitting device according to claim 5, wherein the base of the device substrate is made of an aluminum nitride ceramic.

9. 6. The light emitting device according to claim 5, wherein the thickness of the substrate is from 30 μm to 120 μm.

10. A light emitting device according to claim 5, A multi-unit light emitting device in which the plurality of light emitting devices are disposed adjacent to each other and electrically connected in series or in parallel.

11. a phosphor plate bonded onto the semiconductor light emitting elements via an adhesive member; The light emitting device according to claim 10 , wherein the phosphor plate is integrally formed.

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