Semiconductor light-emitting device and method for manufacturing semiconductor light-emitting device

Abstract

This semiconductor light-emitting device includes: a substrate having, on the upper surface, an element mounting region for having a semiconductor light-emitting element mounted thereon; a pair of wiring patterns made of Al, each of which has a mounting part provided in the element mounting region on the upper surface of the substrate and an extension part extending from the mounting part to the outside of the element mounting region; a pair of pad electrodes formed on the mounting parts of the pair of wiring patterns; and a semiconductor light-emitting element joined to the pair of pad electrodes. Protrusions derived from Al crystal grains are formed on surfaces of the extension parts of the pair of wiring patterns.

Description

Semiconductor light-emitting device and method for manufacturing a semiconductor light-emitting device

[0001] The present invention relates to a semiconductor light-emitting device and a method for manufacturing a semiconductor light-emitting device.

[0002] Light-emitting devices aimed at improving light output have been disclosed. For example, Patent Document 1 discloses a light-emitting device that includes a wiring board, a semiconductor light-emitting element mounted on the wiring board using a flip-chip method, and a sealing cap that seals the semiconductor light-emitting element together with the wiring board, wherein the semiconductor light-emitting element is equipped with a metal reflective layer that reflects light emitted from the light-emitting layer contained in the semiconductor light-emitting element.

[0003] Japanese Patent Publication No. 2014-44971

[0004] Regardless of the light-emitting device disclosed in Patent Document 1, further improvements in optical output are expected in light-emitting devices that have a configuration such as a metal reflective layer that reflects light emitted from the light-emitting layer of a semiconductor light-emitting device.

[0005] This invention has been made in view of the above-mentioned problems, and aims to provide a semiconductor light-emitting device and a method for manufacturing a semiconductor light-emitting device that can achieve an improvement in light output.

[0006] The semiconductor light-emitting device according to the present invention comprises a substrate having an element mounting region on its upper surface on which a semiconductor light-emitting element is mounted, a pair of wiring patterns made of Al each having a mounting portion provided in the element mounting region on the upper surface of the substrate and an extended portion extending outward from the mounting portion, and a pair of pad electrodes formed on the mounting portion of the pair of wiring patterns and a semiconductor light-emitting element joined to the pair of pad electrodes, wherein protrusions derived from Al crystal grains are formed on the surface of the extended portion of the pair of wiring patterns.

[0007] Furthermore, the present invention relates to a method for manufacturing a semiconductor light-emitting device, comprising: a substrate preparation step of preparing a substrate having an element mounting region on its upper surface on which a semiconductor light-emitting element is mounted, a pair of wiring patterns made of Al each having a mounting portion provided in the element mounting region on the upper surface and an extended portion extending outward from the mounting portion to the element mounting region, and a pair of pad electrodes formed on the mounting portion of the pair of wiring patterns; an element bonding step of bonding a semiconductor light-emitting element to the pair of pad electrodes; and a convexity formation step of repeatedly subjecting the substrate on which the pair of wiring patterns and the pair of pad electrodes are formed to a temperature cycle in which the substrate is alternately exposed to a first temperature environment and a second temperature environment higher than the first temperature, thereby forming convexity portions derived from Al crystal grains on the surface of the extended portion of the pair of wiring patterns.

[0008] This is a perspective view of the light-emitting device according to Example 1. This is a top view of the light-emitting device according to Example 1. This is a cross-sectional view of the light-emitting device according to Example 1. This is an enlarged cross-sectional view of the light-emitting device according to Example 1. This is a cross-sectional view showing an example of the manufacturing process of the light-emitting device according to Example 1. This is a cross-sectional view showing an example of the manufacturing process of the light-emitting device according to Example 1. This is a cross-sectional view showing an example of the manufacturing process of the light-emitting device according to Example 1. This is a cross-sectional view showing an example of the manufacturing process of the light-emitting device according to Example 1. This is a graph showing the manufacturing conditions in the manufacturing process of the light-emitting device according to Example 1. This is a top view of the light-emitting device according to Example 2. This is a cross-sectional view of the light-emitting device according to Example 3.

[0009] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In the drawings, identical components are denoted by the same reference numerals, and descriptions of redundant components are omitted.

[0010] The configuration of the light-emitting device 100 according to Embodiment 1 will be described using Figures 1 to 3. Figure 1 is a perspective view of the light-emitting device 100. Figure 2 is a top view of the light-emitting device 100. Figure 3 is a cross-sectional view of the light-emitting device 100 shown in Figure 2, along line 3-3. In Figure 3, the vertical direction is the height direction of the light-emitting device 100, and the horizontal direction is the width direction of the light-emitting device 100.

[0011] [Overview of the Light-Emitting Device 100] As shown in Figure 1, the light-emitting device 100 is configured to include a substrate 11, a light-emitting element 13 and a protective element 15 provided on the substrate 11, and a sealing member 17 that seals the light-emitting element 13 and the protective element 15 together with the substrate 11.

[0012] In Figure 2, the sealing member 17 and the joining member between the substrate 11 and the sealing member 17 are omitted to avoid complexity in the illustration. Also, in Figure 2, the center line CL is shown as a line segment that passes through the center of the upper surface of the substrate 11 and bisects the width of the substrate 11 in the left-right direction in the figure.

[0013] [Substrate 11] First, the substrate 11 and the wiring pattern formed on its surface will be described. The substrate 11 is an insulating substrate having a rectangular top surface shape. In the light-emitting device 100 of this embodiment, the substrate 11 is made of aluminum nitride (AlN).

[0014] As shown in Figures 2 and 3, the upper surface of the substrate 11 has a light-emitting element mounting section 21, a protective element mounting section 22, an extension section 23, and an annular pattern 25. Hereafter, the light-emitting element mounting section 21, the protective element mounting section 22, and the extension section 23 will be collectively referred to as the upper surface wiring pattern.

[0015] The light-emitting element mounting section 21 is a pair of wiring sections provided spaced apart from each other in the approximate center of the upper surface of the substrate 11. Specifically, as shown in Figure 2, the light-emitting element mounting section 21 consists of a first light-emitting element mounting section 21A having an approximate square upper surface shape and straddling the center line CL, and a second light-emitting element mounting section 21B having a rectangular upper surface shape and provided to the left of the center line CL.

[0016] In the upper wiring pattern, the region connecting the outer edges of the first light-emitting element mounting section 21A and the second light-emitting element mounting section 21B is a light-emitting element mounting region for mounting and joining the light-emitting element 13.

[0017] The protective element mounting section 22 is a pair of wiring sections provided spaced apart from each other in an area above the light-emitting element mounting section 21 on the upper surface of the substrate 11. Specifically, as shown in Figure 2, the protective element mounting section 22 consists of a first protective element mounting section 22A and a second protective element mounting section 22B, which are provided so as to be symmetrical with respect to the center line CL and each has a rectangular upper surface shape.

[0018] In the upper wiring pattern, the region connecting the outer edges of the first protective element mounting portion 22A and the second protective element mounting portion 22B is a protective element mounting region for mounting and joining the protective element 15.

[0019] The extension portion 23 is a pair of wiring portions formed on the upper surface of the substrate 11, extending outward from each of the light-emitting element mounting portion 21 and the protective element mounting portion 22. Specifically, as shown in Figure 2, the extension portion 23 consists of a first extension portion 23A extending from each of the first light-emitting element mounting portion 21A and the first protective element mounting portion 22A to the region to the right of the center line CL, and a second extension portion 23B extending from each of the second light-emitting element mounting portion 21B and the second protective element mounting portion 22B to the region to the left of the center line CL.

[0020] In the light-emitting device 100 of this embodiment, each of the first extension portion 23A and the second extension portion 23B, together with the first light-emitting element mounting portion 21A and the first protective element mounting portion 22A, and the second light-emitting element mounting portion 21B and the second protective element mounting portion 22B, each has a substantially semicircular upper surface shape.

[0021] The annular pattern 25 is a wiring portion having an annular upper surface shape that surrounds the upper surface wiring pattern on the upper surface of the substrate 11 while being separated from it. Specifically, the region enclosed by the annular pattern 25 on the upper surface of the substrate 11 is provided with the light-emitting element mounting portion 21, the protective element mounting portion 22, and the expansion portion 23, respectively.

[0022] In the upper wiring pattern, the first light-emitting element mounting portion 21A, the first protective element mounting portion 22A, and the first extension portion 23A, and the second light-emitting element mounting portion 21B, the second protective element mounting portion 22B, and the second extension portion 23B are each integrally patterned and formed.

[0023] In the light-emitting device 100 of this embodiment, each of the light-emitting element mounting section 21, the protective element mounting section 22, the expansion section 23, and the annular pattern 25 is formed on the upper surface of the substrate 11 by forming titanium (Ti) and aluminum (Al) in that order.

[0024] As shown in Figure 3, mounting electrodes 27 for mounting the light-emitting device 100 onto the circuit board are formed on the lower surface of the substrate 11. The mounting electrodes 27 are formed on the lower surface of the substrate 11 spaced apart from each other, and each is a pair of electrodes with a rectangular upper surface shape.

[0025] The mounted electrode 27 is electrically connected to the expansion portion 23 via conductive vias 28 made of conductive metal that penetrate the substrate 11 in the vertical direction in Figure 3. Specifically, the mounted electrode 27 consists of a first mounted electrode 27A electrically connected to the first expansion portion 23A via conductive vias 28, and a second mounted electrode 27B electrically connected to the second expansion portion 23B via conductive vias 28.

[0026] In the light-emitting device 100 of this embodiment, the mounted electrode 27 is formed by stacking Ti, nickel-chromium (Ni-Cr), gold (Au), Ni, and Au in that order on the lower surface (front surface) of the substrate 11. The conductive via 28 described above is made of tungsten (W).

[0027] An element pad electrode 31 is formed on the upper surface of the light-emitting element mounting section 21. Specifically, the element pad electrode 31 consists of a first element pad electrode 31A formed on the upper surface of the first light-emitting element mounting section 21A and a second element pad electrode 31B formed on the upper surface of the second light-emitting element mounting section 21B. Although not shown in the figures, an element pad electrode is also formed on the upper surface of the protective element mounting section 22.

[0028] An annular pad electrode 32 is formed on the upper surface of the annular pattern 25, along the upper surface. In the light-emitting device 100 of this embodiment, the element pad electrode 31 and the annular pad electrode 32 are formed on the upper surface of the light-emitting element mounting section 21 and the upper surface of the annular pattern 25, respectively, with Ti, platinum (Pt), and Au formed in that order.

[0029] [Light-emitting element 13] Next, the configuration of the light-emitting element 13 will be described. The light-emitting element 13 is an element provided in the light-emitting element mounting area on the upper surface of the substrate 11. As shown in Figure 3, the light-emitting element 13 is a light-emitting diode (LED) composed of a support substrate 34, a semiconductor structural layer 35, a first element electrode 36, and a second element electrode 37.

[0030] The support substrate 34 is a flat, insulating substrate with a rectangular top surface. The support substrate 34 is made of, for example, AlN or sapphire (Al ２ O ３ The support substrate 34 is made of a material that is transparent to light emitted from the light-emitting layer contained in the semiconductor structural layer 35, such as the above.

[0031] The semiconductor structure layer 35 is a semiconductor crystal layer of aluminum gallium nitride (AlGaN) crystal system formed on the lower surface of the support substrate 34. The semiconductor structure layer 35 is composed of a p-type semiconductor layer, an emissive layer, and an n-type semiconductor layer (none of which are shown) stacked in this order. Note that each of the p-type semiconductor layer, emissive layer, and n-type semiconductor layer of the semiconductor structure layer 35 may include a superlattice layer, a quantum well layer, a barrier layer, etc.

[0032] The first element electrode 36 and the second element electrode 37 are electrodes electrically connected to the p-type semiconductor layer and the n-type semiconductor layer of the semiconductor structure layer 35, respectively. The first element electrode 36 and the second element electrode 37 are formed on the p-type semiconductor layer and the n-type semiconductor layer in the order of Ti, Al, Ti, and Au, respectively. However, the first element electrode 36 and the second element electrode 37 are not limited to the above materials as long as they can supply power to the semiconductor structure layer 35. For example, Ni, Al, Ti, and Au may also be used.

[0033] Each of the first element electrode 36 and the second element electrode 37 is bonded to each of the first element pad electrode 31A and the second element pad electrode 31B, respectively, via a bonding member 41 made of gold-tin (Au-Sn). In other words, the light-emitting element 13 is flip-chip bonded to the substrate 11.

[0034] In the light-emitting device 100, the first element electrode 36, the first light-emitting element mounting portion 21A, the first extension portion 23A, and the first mounting electrode 27A of the aforementioned light-emitting element 13 act as an anode electrode, and the second element electrode 37, the second light-emitting element mounting portion 21B, the second extension portion 23B, and the second mounting electrode 27B of the aforementioned light-emitting element 13 act as a cathode electrode.

[0035] In the light-emitting device 100, when power is supplied to the light-emitting element 13, ultraviolet light having a peak in a wavelength range of 220 nm to 430 nm is emitted from the light-emitting layer of the semiconductor structure layer 35. The ultraviolet light emitted from the light-emitting layer is emitted to the outside of the light-emitting element 13 from the upper surface and side surfaces of the support substrate 34.

[0036] [Protective Element 15] Next, the protective element 15 will be described. The protective element 15 is an element that has a rectangular top surface shape and is provided in the aforementioned protective element mounting region on the top surface of the substrate 11. The protective element 15 is a Zener Diode (ZD) that bypasses a current flowing in the reverse direction to prevent damage to the light-emitting element 13 when a reverse voltage is applied to the electrode of the light-emitting element 13.

[0037] The protective element 15 includes two element electrodes (not shown) similarly to the light-emitting element 13. Each of the two element electrodes is respectively bonded to an element pad electrode provided on the upper surface of the protective element mounting portion 22 via a bonding member 41.

[0038] Note that as the protective element 15, a varistor (Variable Resistor) that protects the light-emitting element 13 from surge currents that can instantaneously flow beyond a steady state while electricity is externally supplied to drive the light-emitting element 13 and obtains a constant voltage can also be used.

[0039] [Sealing Member 17] Next, the sealing member 17 will be described. As shown in FIG. 3, the sealing member 17 is a light-transmitting body that seals the light-emitting element 13 and the protective element 15 together with the substrate 11 on the substrate 11. In the light-emitting device 100 of the present embodiment, the sealing member 17 is made of a material that has light-transmitting properties with respect to the ultraviolet light emitted from the light-emitting element 13, such as quartz or borosilicate glass.

[0040] The sealing member 17 is composed of a dome portion 17D having an upwardly convex dome shape, and an annular frame portion 17F provided at the lower end of the dome portion 17D. In a plan view of the light-emitting device 100 viewed from above, the sealing member 17 is arranged such that the center of the dome portion 17D overlaps with the center of the light-emitting element 13.

[0041] On the bottom surface of the frame portion 17F of the sealing member 17, a metallized pattern 43 formed by laminating Ni, Ti, and Au in this order on the bottom surface is formed. The metallized pattern 43 provided on the frame portion 17F is bonded to the above-mentioned annular pad electrode 32 via a bonding member 44 made of Au-Sn.

[0042] The sealing member 17 is bonded to the annular pad electrode 32 on the upper surface of the substrate 11, so that together with the substrate 11, it forms a sealing space SP that seals the light-emitting element 13, the protective element 15, the light-emitting element mounting portion 21, the protective element mounting portion 22, and the extension portion 23. In the light-emitting device 100, nitrogen (N ２ ) gas is filled in the sealing space SP as a sealing gas.

[0043] In order to prevent substances such as carbon, graphite, glassy carbon, and diamond-like carbon from depositing on the surface of the light-emitting element 13, the sealing gas may contain about several vol% of oxygen (O ２ ) .

[0044] [Improvement of Light Output of Light-Emitting Device 100] Here, the improvement of the light output of the light-emitting device 100 in the present embodiment will be described with reference to FIG. 4. FIG. 4 is an enlarged view of part A in FIG. 3.

[0045] In the light-emitting device 100 of the present embodiment, as described above, among the upper surface side wiring patterns (the light-emitting element mounting portion 21, the protective element mounting portion 22, and the extension portion 23) formed on the upper surface of the substrate 11, the light-emitting element mounting portion 21 and the protective element mounting portion 22 are covered with element pad electrodes. In other words, in the upper surface side wiring pattern, the extension portion 23 is exposed in the sealing space SP formed by the substrate 11 and the sealing member 17.

[0046] In the light-emitting device 100 of this embodiment, the expanded portion 23 made of Al is subjected to strain stress during the manufacturing of the light-emitting device 100, resulting in the formation of protrusions originating from Al crystal grains on the upper surface 23S of the expanded portion 23. Specifically, the Al crystal plane is exposed on the upper surface 23S of the expanded portion 23, and some of the Al crystal grains protrude upward on this Al crystal plane.

[0047] The upper surface 23S of the expanded portion 23 is uneven due to the presence of protruding Al crystal grains and non-protruding Al crystal grains. This protrusion of crystal grains is thought to be the result of the crystal grains being pushed upward by the strain stress during manufacturing as described above. In Figure 4, to illustrate the formation of Al crystal grains on the upper surface 23S of the expanded portion 23 as an example, only the crystal grains exposed on the upper surface 23S are shown with solid and dashed lines.

[0048] In the light-emitting device 100 of this embodiment, the thickness of the expanded portion 23 before the upper surface 23S becomes uneven is set to approximately 4.3 μm. Furthermore, in the light-emitting device 100 of this embodiment, the diameter of the Al crystal grains in a plan view of the upper surface 23S of the expanded portion 23 after the upper surface 23S has become uneven is set to 2 to 8 μm, and the protrusion height protruding from the upper surface 23S is set to 1 to 2 μm.

[0049] In the light-emitting device 100 of this embodiment, the irregularities formed by the Al crystal grains described above occur only on the upper surface 23S of the expanded portion 23, and such irregularities do not occur on the upper surface of the light-emitting element mounting portion 21, which is also made of Al, or on the upper surface of the element pad electrode 31 formed thereon. In other words, by providing the element pad electrode 31, the irregularities of the underlying Al can be prevented. Similarly, by providing the annular pad electrode 32, the irregularities of the underlying Al can be prevented.

[0050] In the light-emitting device 100, the upper surface 23S of the expansion portion 23 has the aforementioned irregularities. For example, as shown in Figure 4, when light L1 (dotted line in the figure) emitted from the light-emitting element 13 reaches the upper surface 23S, the light L1 is diffusely reflected by the irregularities of the upper surface 23S. That is, the light L1 becomes diffuse light DL1 (solid line in the figure) as shown in Figure 4 and is taken out of the light-emitting device 100 through the sealing member 17.

[0051] For example, if the upper surface 23S of the extension portion 23 is flat, the light L1 emitted from the side of the light-emitting element 13 is specularly reflected by the upper surface 23S. In this way, a portion of the light L1 specularly reflected by the upper surface 23S is directly absorbed by the metallization pattern 43 or the bonding member 44, or it is reflected by the frame portion 17F of the sealing member 17 and then absorbed by the metallization pattern 43. In other words, a portion of the light reflected by the upper surface 23S is absorbed and attenuated inside the light-emitting device 100.

[0052] In the light-emitting device 100 of this embodiment, in addition to the light emitted from the top and side surfaces of the light-emitting element 13 and taken out directly to the outside of the light-emitting device 100, diffused light DL1 diffusely reflected by the top surface 23S of the extension part 23 can also be taken out to the outside of the light-emitting device 100. Therefore, with the light-emitting device 100 of this embodiment, the light output can be improved by utilizing the diffuse reflection of light by the top surface 23S of the extension part 23.

[0053] [Verification] The verification and results of the verification performed on the light-emitting device 100 of this embodiment will be explained below with reference to Figure 5. Figure 5 is a graph showing the maintenance rate of the light output with respect to the number of cycles of processing performed on the light-emitting device 100.

[0054] In this verification, the light-emitting device 100, in a state before Al crystal grains protrude from the upper surface 23S of the expanded portion 23 and the upper surface 23S becomes uneven, i.e., in a state where the upper surface 23S is a flat surface, was subjected to a process (hereinafter also referred to as temperature cycling) in which it was alternately held for a predetermined time under two temperature environments, and the light output of the light-emitting device 100 was measured during this temperature cycling process. Specifically, the device was not energized during the temperature cycling process, and was energized only when measuring the light output. The light output at the start of the measurement (start of the process) was set to 100%, and the light output maintenance rate was normalized and expressed.

[0055] Figure 5 shows the light output maintenance rate of the light-emitting device 100 at the 200th, 400th, 600th, 800th, and 1200th cycles, when the light-emitting device 100 is held at -40°C for 15 minutes, followed by being held at 125°C for 15 minutes, and this process is repeated 1200 times.

[0056] Figure 5 shows that the optical power maintenance rate increased to 102% after 200 cycles from the start of the temperature cycling process. The optical power maintenance rate continued to increase with each subsequent temperature cycling cycle up to 800 cycles, and then leveled off at around 104-105% after 800 cycles.

[0057] From these results, it can be inferred that on the upper surface 23S of the expanded portion 23, the unevenness of the upper surface 23S progresses particularly when the number of processing cycles is between 200 and 600, meaning that the Al crystal grains protrude from the upper surface 23S, making the diffuse reflection described above more likely to occur.

[0058] Furthermore, since the optical output maintenance rate has almost leveled off after 800 processing cycles, it can be inferred that the unevenness of the upper surface 23S of the extended portion 23 has almost stopped progressing. In other words, it can be said that the unevenness phenomenon has reached saturation.

[0059] Furthermore, when the light-emitting device 100 was observed from above before and after processing, the upper surface 23S of the expanded section 23 was gray to black at the start of processing (processing cycle count 0), whereas the upper surface 23S of the expanded section 23 was white after 1200 processing cycles.

[0060] The above describes the evaluation of the light output maintenance rate when the light-emitting device 100 was subjected to temperature cycling. As a result, it was confirmed that the light output maintenance rate of the light-emitting device 100 improved by about 5% from the initial state (0 cycles) up to approximately 800 cycles. Furthermore, it was confirmed that the light output maintenance rate remained almost constant after 800 cycles.

[0061] [Method for Manufacturing the Light-Emitting Device 100] The method for manufacturing the light-emitting device 100 will be described below with reference to Figures 6 to 10. Figures 5 to 9 are cross-sectional views showing an example of the manufacturing process for the light-emitting device 100. Figure 10 is a graph (temperature cycle chart) showing the manufacturing conditions in the manufacturing process for the light-emitting device 100. Note that the substrate 11 is connected in a sequence equal to the number of light-emitting devices 100 manufactured at one time, but only one of them is shown in Figures 6 to 9.

[0062] The light-emitting device 100 is manufactured by a procedure that includes a substrate preparation step of preparing a substrate 11, an element bonding step of bonding a light-emitting element 13 and a protective element 15 to the substrate 11, a sealing member bonding step of bonding a sealing member 17 to the substrate 11, a piece-forming step of dividing the light-emitting device 100 into individual pieces, and a surface irregularity forming step of forming irregularities on the upper surface 23S of the expanded portion 23.

[0063] [Substrate preparation process] First, as shown in Figure 6, a substrate 11 is prepared on which an upper surface wiring pattern consisting of a light-emitting element mounting section 21, a protective element mounting section 22, and an extension section 23, an annular pattern 25, mounting electrodes 27, conductive vias 28, element pad electrodes 31, and annular pad electrodes 32 are formed.

[0064] In the manufacturing of the substrate 11, the upper surface wiring pattern, mounting electrodes 27, conductive vias 28, element pad electrodes 31, and annular pad electrodes 32 are each formed by sequentially patterning various metals using a film deposition method such as sputtering, electroless plating, or electrolytic plating.

[0065] [Element Bonding Process] Next, as shown in Figure 7, the light-emitting element 13 and the protective element 15 are bonded to the upper surface of the substrate 11. Note that only the bonding method for the light-emitting element 13 is shown here, and the bonding method for the protective element 15 is the same as for the light-emitting element 13, so it is not shown.

[0066] First, a solder paste containing 20 wt% fine particles of Au-Sn, which will become the bonding member 41 after hardening, is applied to the surface of the element pad electrode 31 by screen printing or potting. Similarly, solder paste is also applied to the surface of the pad electrode provided on the protective element mounting section 22.

[0067] Next, the light-emitting element 13 is placed on the element pad electrode 31 to which solder paste has been applied, such that the first element electrode 36 and the second element electrode 37 overlap. Similarly, the protective element 15 is placed on the pad electrode to which solder paste has been applied, such that the element electrodes overlap.

[0068] Subsequently, the solder paste is heated to 300°C in a reflow oven, melting and solidifying the 20 wt% Au-Sn fine particles contained in the solder paste to form the bonding member 41, completing the bonding of the light-emitting element 13 and the protective element 15. Note that paste components other than Au-Sn volatilize during the reflow process.

[0069] In this bonding process, instead of providing a bonding member on the surface of the element pad electrode 31, a bonding member may be provided on the surface of the first element electrode 36 and the second element electrode 37 of the light-emitting element 13. In this case, the light-emitting element 13 is bonded by thermocompression fusion bonding.

[0070] [Sealing Member Bonding Process] Next, as shown in Figure 8, a sealing member 17 that seals the upper wiring pattern, the light-emitting element 13, and the protective element 15 is bonded. First, an AuSn ribbon made of 20 wt% Au-Sn, which will become the bonding member 44 after melt curing, is temporarily fixed onto the annular pad electrode 32. Alternatively, this AuSn ribbon may be temporarily fixed onto the metallized pattern 43 side of the sealing member 17.

[0071] Next, the sealing member 17 is placed on the substrate 11 so that the metallized pattern 43 provided on the frame portion 17F and the annular pad electrode 32 overlap, and thermocompression fusion bonding is performed by pressing the AuSn ribbon described above at 300°C while melting and hardening it.

[0072] By performing this thermocompression fusion bonding under a nitrogen atmosphere, nitrogen gas is sealed between the substrate 11 and the sealing member 17, and the bonding of the sealing member 17 is completed. After the bonding of the sealing member 17 is complete, the sealing space SP is filled with nitrogen gas.

[0073] [Individualization Process] Next, as shown in Figure 9, the individual light-emitting devices 100 are separated into individual pieces along the light-emitting device dividing lines of the substrate 11, which is an integrated substrate 11, using a dicing blade DB (or laser dicing) in a grid pattern. In this embodiment, the substrate 11 was cut using a dicing blade DB with abrasive grain sizes of #400 to #800.

[0074] [Irregularity Formation Process] Finally, an irregularity formation process is performed on the upper surface 23S of the expanded portion 23 by alternately exposing the individualized light-emitting device 100 to a high-temperature environment and a low-temperature environment at a constant interval. In this process, as shown in Figure 10, a temperature cycle treatment was repeated 1200 times in which the light-emitting device 100 was held at -40°C for 15 minutes, and then held at 125°C for 15 minutes.

[0075] Here, the thermal expansion coefficient of AlN, which is the constituent material of the substrate 11, is 2.8 × 10⁻⁶. －６ The temperature is / °C, and the thermal expansion coefficient of Al, which is the constituent material of the expanded portion 23, is 22 × 10⁻⁶. －６ The temperature is / °C. In other words, Al expands nearly eight times more easily with heat than AlN.

[0076] In the temperature cycling process in this step, the light-emitting device 100 is repeatedly exposed to a relatively low temperature environment (-40°C) and a high temperature environment (125°C) for a short period of time (15 minutes). Due to the difference in thermal expansion coefficients between AlN and Al, strong strain stress is applied to the light-emitting element mounting section 21 and the expanded section 23, which are made of Al.

[0077] At this time, in the expanded portion 23, a change occurs in the crystal structure of Al to relieve the strain stress acting on the expanded portion 23. Specifically, on the surface of the expanded portion 23 (the crystal plane of Al) exposed to the sealing space SP, some of the Al crystal grains protrude upward. In this way, irregularities are formed on the upper surface 23S of the expanded portion 23 by the protruding Al crystal grains and the non-protruding crystal grains.

[0078] On the other hand, in the light-emitting element mounting section 21, the strain stress applied to the light-emitting element mounting section 21 is relieved by the element pad electrode 31 that covers the light-emitting element mounting section 21. As a result, the aforementioned irregularities are not formed on the surface of either the light-emitting element mounting section 21 or the element pad electrode 31. In other words, the formation of the aforementioned irregularities can be prevented by forming the element pad electrode 31 on the light-emitting element mounting section 21.

[0079] As described above, the light-emitting device 100 of the present embodiment can be manufactured by the manufacturing method including the substrate preparation step, element bonding step, sealing member forming step, singulation step and unevenness forming step described above. It should be noted that the above-described unevenness forming step is not limited to being performed after the singulation step, and may be performed at other timings. For example, the unevenness forming step may be performed after the substrate preparation step.

[0080] In particular, when the unevenness forming step is performed after the substrate preparation step (before the element bonding step), unnecessary stress due to thermal cycles is not applied to the light-emitting element 13 and the protection element 15, so it is preferable to perform the steps in this order.

[0081] It should be noted that, in the temperature cycle treatment in the above-described unevenness forming step, the temperature conditions are set to -40°C and 125°C, but the present invention is not limited thereto. For example, by setting the first temperature to 0°C or lower and the second temperature to 100°C or higher, and more preferably by setting the difference between the first temperature and the second temperature to 150°C or higher, there is a high probability that unevenness will be formed on the upper surface 23S of the extended portion 23.

[0082] In the light-emitting device 100 of the present embodiment, AlN, which has a large difference in coefficient of thermal expansion from Al, is used for the substrate 11, but it is sufficient that the substrate 11 has a coefficient of thermal expansion at least several times higher than that of Al. For example, instead of AlN, the coefficient of thermal expansion is about 4.5×10 －６ / °C or less adjusted alumina (Al ２ O ３ ) as a main material, or silicon nitride (Si －６ having a coefficient of thermal expansion of about 3.5×10 ３ N ４ ) or other ceramics may be used.

[0083] Next, the light-emitting device 110 according to Example 2 will be described with reference to FIG. 11. FIG. 11 is a top view of the light-emitting device 110 according to Example 2. The light-emitting device 110 differs from Example 1 in the shapes of the extended portion 23, the annular pattern 25, and the sealing member 17, and is the same as Example 1 in other respects. In FIG. 11, the sealing member 17 is indicated by a dashed-dotted line.

[0084] In the light-emitting device 110 of this embodiment, the first extension portion 23A and the second extension portion 23B, together with the first light-emitting element mounting portion 21A and the first protective element mounting portion 22A, and the second light-emitting element mounting portion 21B and the second protective element mounting portion 22B, each have a substantially rectangular upper surface shape. Furthermore, the annular pattern 25 surrounding the light-emitting element mounting portion 21, the protective element mounting portion 22, and the extension portion 23 also has a substantially rectangular upper surface shape.

[0085] In the light-emitting device 110 of this embodiment, the frame portion 17F of the sealing member 17 has a substantially rectangular top surface shape. In a plan view of the light-emitting device 110 from above, the extension portion 23 extends outward beyond the outer edge of the dome portion 17D of the sealing member 17.

[0086] In the light-emitting device 110 of this embodiment, the extended portion 23 extends further outward compared to the light-emitting device 100 of Embodiment 1. That is, the area of ​​the extended portion 23 in the light-emitting device 110 is larger than the area of ​​the extended portion 23 in the light-emitting device 100.

[0087] Therefore, with the light-emitting device 110 of this embodiment, the light emitted from the light-emitting element 13 is more likely to reach the upper surface 23S, which is the diffuse reflective surface of the extension portion 23, thus making it easier to diffusely reflect the light. Thus, with the light-emitting device 110 of this embodiment, the light output can be improved compared to the light-emitting device 100 of Embodiment 1.

[0088] Next, the light-emitting device 120 according to Embodiment 3 will be described with reference to Figure 12. Figure 12 is a cross-sectional view of the light-emitting device 120 according to Embodiment 3. The light-emitting device 120 differs from Embodiment 1 in the formation of the sealing member and its joint portion, but is otherwise similar to Embodiment 1.

[0089] In the light-emitting device 120 of this embodiment, the annular pad electrode 32 is not formed on the annular pattern 25. Also, in the light-emitting device 120 of this embodiment, the upper surface 25S of the annular pattern 25 is uneven due to protruding Al crystal grains on the upper surface 25S, similar to the upper surface 23S of the expanded portion 23.

[0090] In the light-emitting device 120 of this embodiment, the sealing member 46 is a transparent member having an upwardly convex hemispherical shape and covering the area on the upper surface of the substrate 11 that is inside the outer edge of the annular pattern 25. In a plan view of the light-emitting device 120 from above, the sealing member 46 is formed so that its center overlaps with the center of the light-emitting element 13.

[0091] The sealing member 46 covers and seals the light-emitting element 13 and the protective element 15 to protect them, and also functions as a convex lens that transmits light emitted from the light-emitting element 13 and guides the light to the outside of the light-emitting device 100. In the light-emitting device 120, the sealing member 46 is made of a dimethyl silicone resin that is light-resistant to ultraviolet light (UVA-I) with a wavelength longer than 340 nm emitted from the light-emitting element 13.

[0092] Furthermore, when the light-emitting element 13 emits ultraviolet light, the constituent material of the sealing member 46 may be any material that is light-resistant to ultraviolet light, and is not limited to dimethyl silicone resin. For example, amorphous fluororesin with light resistance up to the short wavelength range of 200 nm can be used. Also, when the light-emitting element 13 emits visible light such as blue light, epoxy resin or the like may be used.

[0093] In the light-emitting device 120 of this embodiment, the sealing member 46 is in contact with the upper surface 23S of the expanded portion 23 and the upper surface 25S of the annular pattern 25. As described above, the upper surfaces 23S and 25S are uneven due to the protrusion of Al crystal grains on the upper surfaces 23S and 25S.

[0094] With this configuration, the light-emitting device 120 of this embodiment has improved physical adhesion to the upper surfaces 23S and 25S of the sealing member 46, making it less likely for the sealing member 46 to detach from the substrate 11. In other words, according to the light-emitting device 120 of this embodiment, in addition to improving the light output of the emitted light, the reliability of the light-emitting device can also be improved.

[0095] As a method for manufacturing the sealing member 46 in the light-emitting device 120 of this embodiment, methods such as potting of the resin solution that will become the sealing member 46 after curing, compression molding using a mold, or transfer molding can be applied.

[0096] In this embodiment, the manufacturing process for the light-emitting device 120 involves first forming irregularities on the upper surface 23S of the expanded portion 23 and the upper surface 25S of the annular pattern 25, and then forming the sealing member 46. This improves the adhesion of the sealing member 46 to the substrate 11.

[0097] In addition, the shapes of the dome portion 17D of the sealing member 17 and the sealing member 46 shown in Examples 1 to 3 are not limited to a hemispherical shape, but may be, for example, elliptical, cubic, or rectangular.

[0098] The light-emitting devices 100, 110, and 120 described in the above-mentioned embodiments can be used as light sources for various devices. For example, the light-emitting devices 100, 110, and 120 can be used as curing light sources for resin curing devices or observation light sources for analytical devices.

[0099] 100, 110, 120 Light-emitting device 11 Substrate 13 Light-emitting element 15 Protective element 17, 46 Sealing member 21 Light-emitting element mounting section 22 Protective element mounting section 23 Expansion section 25 Annular pattern 27 Mounting electrode 28 Conductive via 31 Element pad electrode 32 Annular pad electrode 34 Support substrate 35 Semiconductor structure layer 36 First element electrode 37 Second element electrode 41, 44 Bonding member 43 Metallized pattern

Claims

1. A semiconductor light-emitting device comprising: a substrate having an element mounting region on its upper surface on which a semiconductor light-emitting element is mounted; a pair of wiring patterns made of Al, each having a mounting portion provided in the element mounting region on the upper surface of the substrate and an extended portion extending outward from the mounting portion; and a pair of pad electrodes formed on the mounting portion of the pair of wiring patterns and a semiconductor light-emitting element joined to the pair of pad electrodes, wherein protrusions derived from Al crystal grains are formed on the surface of the extended portion of the pair of wiring patterns.

2. The semiconductor light-emitting apparatus according to claim 1, characterized in that it has an annular pattern made of metal that is separated from the pair of wiring patterns and surrounds the pair of wiring patterns, and an annular pad electrode formed thereon, and a light-transmitting sealing member that is bonded to the annular pad electrode and forms a sealing space for sealing the semiconductor light-emitting element together with the substrate.

3. The semiconductor light-emitting apparatus according to claim 1, characterized in that it has a translucent sealing member that is separated from the pair of wiring patterns and has an annular pattern made of metal surrounding the pair of wiring patterns, and that covers the surface of the semiconductor light-emitting element, sealing the semiconductor light-emitting element while extending onto the annular pattern.

4. The semiconductor light-emitting apparatus according to claim 3, characterized in that the annular pattern is made of Al, and protrusions originating from Al crystal grains are formed on the surface of the annular pattern.

5. The semiconductor light-emitting apparatus according to any one of claims 1 to 4, characterized in that the substrate is made of AlN.

6. The semiconductor light-emitting apparatus according to any one of claims 1 to 4, characterized in that the pad electrode is formed by stacking Ti, Pt, and Au in that order on the mounting portion described above.

7. The semiconductor light-emitting device according to any one of claims 1 to 4, characterized in that the semiconductor light-emitting element emits ultraviolet light.

8. A method for manufacturing a semiconductor light-emitting device, comprising: a substrate preparation step of preparing a substrate having an element mounting region on its upper surface for mounting a semiconductor light-emitting element, a pair of wiring patterns made of Al each having a mounting portion provided in the element mounting region on the upper surface and an extended portion extending outward from the mounting portion to the element mounting region, and a pair of pad electrodes formed on the mounting portion of the pair of wiring patterns; an element bonding step of bonding a semiconductor light-emitting element to the pair of pad electrodes; and a convexity formation step of repeatedly subjecting the substrate on which the pair of wiring patterns and the pair of pad electrodes are formed to a temperature cycle in which the substrate is alternately exposed to a first temperature environment and a second temperature environment higher than the first temperature, thereby forming convexity portions derived from Al crystal grains on the surface of the extended portion of the pair of wiring patterns.

9. The method for manufacturing a semiconductor light-emitting apparatus according to claim 8, characterized in that the first temperature is at least 0°C or lower, and the second temperature is at least 100°C or higher.

10. The method for manufacturing a semiconductor light-emitting apparatus according to 8 or 9, characterized in that the temperature cycle is repeated at least 200 times.

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