Light-emitting device

Abstract

To provide a light-emitting device in which separation between resin and lead frame is prevented, die share strength is high, and disconnection defect or the like hardly occurs.SOLUTION: A device includes: a plurality of tabular electrodes 12A and 12B; a resin frame body provided to enclose a whole outer periphery of a plurality of lead electrodes while filling the gap between the plurality of lead electrodes, and having an opening to expose the plurality of lead electrodes; and a semiconductor light-emitting element mounted on the plurality of lead electrodes exposed through an opening. A corner and / or outer surface of the frame body has a recess 23 in which an end part of the lead electrode is exposed inside at a position set back from outer surfaces 22A and 22B of the frame body.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0006] ,

[0007] ,

[0001] The present invention relates to a light-emitting device, particularly a light-emitting device in which a semiconductor light-emitting element such as a light-emitting diode (LED) is mounted on a lead frame.

Background Art

[0002] Conventionally, a light-emitting device formed by providing a resin body on a lead frame by insert molding and cutting with a dicing machine is known.

[0003] For example, Patent Document 1 discloses a method of forming a resin molded body on a lead frame provided with a notch portion and cutting the resin molded body and the lead frame along the notch portion to form a light-emitting device.

[0004] Further, Patent Document 2 discloses a surface-mount type light-emitting device having a first resin molded body formed by integrally molding a light-emitting element and first and second leads, and a second resin molded body containing a phosphor that coats the light-emitting element.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, there are problems such as peeling between the resin and the lead frame, reduction in die shear strength, and disconnection defects due to cutting of the integrally molded resin and lead frame.

[0007] The present invention has been made in view of the above-mentioned points, and aims to provide a light-emitting device that prevents delamination between the resin and the lead frame, has high die-sher strength, and is less prone to wire breakage defects. [Means for solving the problem]

[0008] The light-emitting device according to one embodiment of the present invention is Multiple plate-shaped lead electrodes, A resin frame is provided so as to fill the gaps between the plurality of lead electrodes and surround the entire outer circumference of the plurality of lead electrodes, and has an opening that exposes the plurality of lead electrodes, The system comprises a semiconductor light-emitting element mounted on the plurality of lead electrodes exposed from the opening, A semiconductor light-emitting device wherein the corners and / or outer surfaces of the frame have recesses in which the ends of the lead electrodes are exposed at a position set back from the outer surface of the frame. [Brief explanation of the drawing]

[0009] [Figure 1A] This is a conceptual diagram showing the main parts of the light-emitting device 10 according to the first embodiment of the present invention, and is a perspective view taken from the top side. [Figure 1B] This is a conceptual diagram showing the main parts of a light-emitting device 10 according to the first embodiment of the present invention, and is a perspective view taken from the bottom side. [Figure 2A] This is a diagram showing the top view of the light-emitting device 10. [Figure 2B] This is a cross-sectional view along line AA shown in Figure 2A. [Figure 2C] This is a side view as seen from direction B, as shown in Figure 2A. [Figure 3] This figure shows the top surface of the light-emitting device 10 before filling with the covering member 35. [Figure 4] This diagram shows the back surface (the side mounted on the circuit board) of the light-emitting device 10. [Figure 5] This is a partially enlarged perspective view showing a magnified view of the recess 23. [Figure 6]It is a partial enlarged perspective view showing an enlarged view of a solder joint when the light-emitting device 10 is mounted on the wiring 41 of the circuit board 40 using solder 45. [Figure 7] It is a partial enlarged perspective view showing an enlarged view of an arc-shaped (fan-shaped) concave portion 23 which is a modification example of the present embodiment. [Figure 8] It is a flowchart showing a method for manufacturing the light-emitting device 10. [Figure 9A] It is a top view showing manufacturing steps S1 and S2 of the light-emitting device 10. [Figure 9B] It is a top view showing manufacturing step S3 of the light-emitting device 10. [Figure 9C] It is a top view showing manufacturing step S4 of the light-emitting device 10. [Figure 9D] It is a top view showing manufacturing step S5 of the light-emitting device 10. [Figure 9E] It is a top view showing manufacturing steps S6 and S7 of the light-emitting device 10. [Figure 9F] It is a top view showing manufacturing step S8 of the light-emitting device 10. [Figure 9G] It is a top view showing manufacturing step S9 of the light-emitting device 10. [Figure 10A] It is a schematic top view showing an enlarged view of an intersection portion X of the lead frame 12. [Figure 10B] It is a cross-sectional view showing a cross-section of the intersection portion X in steps S4 and S5. [Figure 10C] It is a view showing a removal region RC of the lead frame 12 when forming the arc-shaped concave portion 23.

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described, but they may be appropriately modified and combined. Also, in the following description and the accompanying drawings, substantially the same or equivalent parts will be denoted by the same reference numerals for description. [First Embodiment] Figures 1A and 1B are conceptual diagrams showing the main parts of a light-emitting device 10 according to a first embodiment of the present invention, and are perspective views from the top and bottom sides, respectively. The light-emitting device 10 has a plurality of lead electrodes (hereinafter also simply referred to as leads) and a resin frame 22. In the following description, the case in which the light-emitting device 10 has two leads 12A and 12B will be described, but the light-emitting device 10 may have three or more leads.

[0011] As shown in Figure 1A, the resin frame 22 is provided with an opening 25 in which a light-emitting element is mounted, and the opening 25 is filled with a covering member 35.

[0012] As shown in Figure 1B, recesses 23 are provided at the four corners on the back side of the light-emitting device 10, in which the corners of leads 12A and 12B are exposed internally.

[0013] Figure 2A is a top view of the light-emitting device 10, and Figure 2B is a cross-sectional view along line AA shown in Figure 2A. Figure 2C is a side view as seen from direction B shown in Figure 2A. Figure 3 is a top view of the light-emitting device 10 before the covering member 35 is filled, and Figure 4 is a view of the back surface (mounting surface for the circuit board) of the light-emitting device 10.

[0014] (1) Resin frame and lead The light-emitting device 10 has plate-shaped leads 12A (first electrode) and leads 12B (second electrode). The core material of leads 12A and leads 12B is made of copper (Cu), a metal with good etching properties (corrosive properties), and its surface is plated with nickel / gold (Ni / Au), a metal with corrosion resistance.

[0015] For the core material of leads 12A and 12B, corrosive metals such as aluminum (Al) and iron alloys such as iron-nickel-cobalt (Fe-Ni-Co) can be used.

[0016] Furthermore, corrosion-resistant metals such as platinum (Pt), palladium (Pd), and rhodium (Rh) can be used on the surfaces of leads 12A and 12B.

[0017] In this specification, the lead pair 12, consisting of leads 12A and 12B (hereinafter also referred to as the lead frame 12 of the light-emitting device 10), is formed on substantially the same plane, spaced apart from each other by a gap (slit) 12G between leads 12A and 12B. In the following, unless otherwise specified, leads 12A and leads 12B will simply be referred to as leads.

[0018] A resin frame 22 is insert-molded onto leads 12A and 12B, and the resin frame 22 is provided so as to fill the gap between the leads and surround the entire outer circumference of the leads, thus forming a resin package. In other words, the leads are not exposed on the outer surface of the resin frame 22 or on a surface substantially flush with the outer surface.

[0019] The resin frame 22 is formed, for example, by adding titanium oxide particles to silicone resin, epoxy resin, or acrylic resin (white resin). Alternatively, it may be formed by adding carbon black to silicone resin, epoxy resin, or acrylic resin (black resin).

[0020] As shown in Figures 1A and 1B, the resin frame 22 has a rectangular shape (rectangular column shape) and has two outer surfaces 22A that are parallel to each other and two outer surfaces 22B that are perpendicular to the outer surfaces 22A. In addition, recesses 23 are provided at the four corners on the back side of the resin frame 22, into which the corners of leads 12A and 12B are exposed internally.

[0021] As shown in Figure 2C, a thin-walled portion 12T is provided on the outer edge WS of leads 12A and 12B, excluding the corners. Also, as shown in Figure 4, a thin-walled portion 12T is provided on the edge WO where leads 12A and 12B face each other. The edges of leads 12A and 12B are covered by the resin of the resin frame 22 by the thin-walled portion 12T, preventing the leads from peeling off the resin frame 22 during dicing or other processes.

[0022] This thin-walled portion 12T is formed by so-called half-etching, which removes material to a depth of, for example, about 50% of the thickness of leads 12A and 12B.

[0023] (2) Recess of the resin frame The light-emitting device 10 is mounted by placing its back surface (i.e., the back surface of the resin frame 22) on a circuit board or the like, and using solder or the like. As shown in Figures 1B and 4, recesses 23 are provided at the four corners of the back side (mounting surface side) of the resin frame 22.

[0024] Furthermore, as described above, the resin frame 22 is provided to fill the gaps between the leads and surround the entire outer circumference of the leads, but the ends of the leads are exposed inside the recesses 23.

[0025] (Rectangular recess) Figure 5 is a partially enlarged perspective view showing a magnified view of the recess 23. In the recess 23, the resin frame 22 is recessed from the outer surfaces 22A and 22B, and the rectangular corners of the lead 12A are exposed within the recess 23. The description above focuses on the recess 23 where the corners of the lead 12A are exposed, but the same applies to the recess 23 where the corners of the lead 12B are exposed.

[0026] Specifically, within the recess 23, the end face 12E of the corner of the lead 12A is positioned set back inward from the outer surfaces 22A and 22B of the resin frame 22. That is, within the recess 23, the resin frame 22 has a rectangular (L-shaped) bottom surface 22H, and the end face 12E of the lead 12A is positioned set back inward from the outer surfaces 22A and 22B by a distance LS (Figure 4).

[0027] Furthermore, fillet guards 22G, which are partition walls of the resin frame 22, are formed on both sides of the corner portion of lead 12A. The fillet guards 22G and bottom surface 22H of the resin frame 22 define a rectangular space within the recess 23 for housing the solder fillet. In other words, the recess 23 functions as a rectangular housing for housing the solder fillet.

[0028] As will be described later, when the bottom surface 22H is formed by etching the lead 12A, the depth (height) of the bottom surface 22H and the fillet guard 22G is approximately the same as the thickness of the lead 12A.

[0029] Furthermore, when a recess 23 is formed by etching the core material 12C of the lead frame 12, and milling of the lead frame surface layer (plating layer) is used in conjunction with this etching, as shown in Figures 4 and 5, the outer periphery 22R1 of the back surface 22R of the resin frame 22 is formed to be slightly lower than the back surface 22R and to have a step 22S relative to the back surface 22R.

[0030] In this case, even if there is a burr on the lower end of the outer surface of the resin frame 22 of the light-emitting device 10, the light-emitting device 10 can be mounted so that it does not float away from the circuit board. Therefore, it is possible to mount the device with high die-shear strength without compromising heat dissipation or reliability.

[0031] Furthermore, when mounting the light-emitting device 10 on a wiring pattern of the same size as the light-emitting device 10, even if there are burrs on the periphery of the wiring pattern, the light-emitting device 10 will not tilt, and optical axis misalignment can be prevented.

[0032] Furthermore, the back surface 22R of the resin frame 22 may be a flat surface without a step 22S. For example, the recess 23 may be formed by removing only the surface layer (plating layer) of the lead frame 12 using a micro milling machine or the like, so as not to create a step 22S.

[0033] Figure 6 is a magnified partial perspective view showing an enlarged view of the solder joint when the light-emitting device 10 is mounted on the wiring (lands) 41 of the circuit board 40 using solder 45.

[0034] Since the fillet of solder 45 is formed within the recess 23, high die-shear strength can be maintained even when mounted on wiring of a similar size to that of the light-emitting device 10.

[0035] (arc-shaped recess) Figure 7 is a partially enlarged perspective view showing an enlarged view of a recess 23, which is a modified example of this embodiment. In this modified example, an arc-shaped (fan-shaped) recess 23 is formed.

[0036] More specifically, within the recess 23, the bottom surface 22H of the resin frame 22 has an arc shape (or a quadrant shape), and the end surface (side surface) 12E of the end of the lead 12A has the shape of a cylindrical side surface.

[0037] Furthermore, fillet guards 22G, which are partition walls extending from the resin frame 22 and protruding, are formed on both sides of the end of lead 12A. The fillet guards 22G and the bottom surface 22H of the resin frame 22 define a quarter-cylindrical space in the recess 23 that accommodates the solder fillet. In other words, the arc-shaped recess 23 functions as a accommodating section for the solder fillet. Such protruding fillet guards 22G can increase die shear strength by clamping a portion of the solder fillet in a necking manner.

[0038] Similar to the case of the rectangular recess 23 described above, the solder fillet 45 is formed within the recess 23, so that high die-shear strength can be maintained even when mounted on wiring of a similar size to that of the light-emitting device 10.

[0039] In addition, although the above description has focused on cases where the recess 23 of the resin frame 22 is rectangular or arc-shaped, the recess 23 only needs to be formed such that the end face of the lead is exposed inside and there is a space for accommodating the solder fillet connected to the end face of the lead.

[0040] Furthermore, although the example given is that the recess 23 is provided at the corner of the light-emitting device 10 (i.e., the resin frame 22), the explanation is not limited to this. For example, it may be provided on the side of the light-emitting device 10. More specifically, referring to Figure 4, the connection portion 12AJ or 12BJ between the lead 12A or 12B and the adjacent lead may be formed as a rectangular (for example, I-shaped) recess 23. Therefore, the recess 23 may be provided at the corner and / or side of the light-emitting device 10.

[0041] (3) Internal structure of the light-emitting device and light-emitting element As shown in Figure 3, the resin frame 22 has an opening 25 (first opening) which is the inner region of the frame, and a portion of the surfaces of leads 12A and 12B are exposed through the opening 25. A semiconductor light-emitting element (hereinafter simply referred to as a light-emitting element) 30 is mounted inside the opening 25.

[0042] In this embodiment, the light-emitting element 30 consists of a light-emitting element, an LED (Light Emitting Diode) 31, and an optical element, a phosphor 32, provided on the light-emitting element. However, the light-emitting element may be a laser diode (LD) or the like. Furthermore, the optical element is not limited to a phosphor. Also, the optical element may not be provided at all.

[0043] More specifically, for example, lead 12A is the anode electrode and lead 12B is the cathode electrode. The p electrode of LED 31 is connected to and mounted on lead 12A, and the n electrode of LED 31 is connected to lead 12B with a bonding wire.

[0044] Furthermore, a plate-shaped phosphor 32 is provided on the LED 31. Alternatively, the light-emitting element 30 may have an optical element such as a light-transmitting body provided on the LED 31. The phosphor is not particularly limited, but various phosphors such as YAG (yttrium aluminum garnet), LuAG (lutetium aluminum garnet), GYAG (gadolinium aluminum garnet), α, β sialon, SCASN, CASN, KFS, etc. can be used as appropriate. In addition, if an optical element such as a light-transmitting body is provided, nanoparticle light-converting members such as cadmium selenide (CdSn), indium phosphide (InP), or indium nitride (InN) can be arranged on the upper surface (light-emitting surface) of the LED 31. In particular, it is preferable to arrange the nanoparticle light-converting member within several hundred nanometers from the upper surface of the LED 31, as this improves the light conversion efficiency through quantum coupling.

[0045] Furthermore, a Zener diode, which is a protective element 33, is bonded and mounted on the lead 12B exposed through the opening 25. The other electrode of the protective element 33 is connected to lead 12A by a bonding wire.

[0046] A varistor or the like can be used as the protective element 33. Passive elements such as capacitors, resistors, and photodetectors may also be provided.

[0047] The opening 25 of the resin frame 22 is filled with a covering member 35, which is a sealing resin or coating resin, filling the space around the light-emitting element 30. Note that in Figure 3, the covering member 35 is not shown for the purpose of explaining the internal structure. The surface of the light-emitting element 30 (i.e., the surface of the phosphor 32) is exposed from the covering member 35.

[0048] As shown in Figure 3, the resin frame 22 has a rectangular shape when viewed from above and has a rectangular column-shaped opening 25 which is the inner region of the frame. Note that the opening 25 is not limited to a rectangular column shape, but may also have a cylindrical shape, a frustoconical shape, or other shapes.

[0049] (4) Method for manufacturing a light-emitting device The manufacturing method of the light-emitting device 10 will be described in detail below with reference to flowcharts and drawings.

[0050] Figure 8 is a flowchart illustrating the manufacturing method of the light-emitting device 10. Figures 9A to 9G are top views showing each step of the process. Figures 9A, 9B, and 9E to 9G are top views, while Figures 9C and 9B are rear views. In each figure, for clarity, the cutting line CL used when dividing the device into sections is shown as a solid line, and the element mounting section is shown as a dotted line.

[0051] (S1) Cutting process The prepared copper (Cu) plate that will become the lead frame 12 is punched out with a die to form the punched-out portion 12N (Figure 9A). Alternatively, a resist mask may be formed and the shape removed by etching. Furthermore, when forming the thin-walled portion 12T on the outer edge of the lead frame 12, a resist mask with an opening for the portion to be the thin-walled portion 12T is formed before forming the punched-out portion 12N, and the portion is thinned by etching.

[0052] (S2) Plating process Nickel (Ni) and gold (Au) are plated onto the upper surface of the lead frame 12 in this order by electroplating (Ni / Au plating) (Figure 9A).

[0053] (S3) Frame forming process Next, a resin frame 22 made of thermosetting resin is formed on the lead frame 12 by insert molding (Figure 9B). The resin frame 22 has an opening 25 which is the inner region of the resin frame 22, and a portion of the surface of the leads 12A and leads 12B is exposed through the opening 25.

[0054] (S4) Plating removal process Figure 10A is a schematic top view showing an enlarged view of the intersection X of the cutting line CL of the lead frame 12 (see Figures 9C and 9D), and Figure 10B is a cross-sectional view showing the cross section of the intersection X in processes S4 and S5.

[0055] First, the plating layer 12P on the surface of the lead frame 12 is removed by dicing (using rectangular teeth) along the cutting line CL in a certain width (plating removal area RB) (Figure 10B, upper panel). The core material 12C (Cu) is exposed in the plating removal area RB (Figure 9C).

[0056] In addition, at this time, the outer circumference 22R1 of the back surface 22R of the resin frame 22 is also shaved off, forming a step 22S that is slightly lower than the back surface 22R (see Figure 5).

[0057] In addition to dicing, the plating layer 12P may also be removed by milling or other methods.

[0058] (S5) Lead frame removal process Next, the core material 12C(Cu) of the lead frame 12 in the plating removal area is etched using an etching solution (Figure 10B, middle section).

[0059] Next, the plating layer 12P on the resin frame 22 side is removed by air blasting (Figure 10B, lower panel). Other removal methods include water jet blasting. It is also possible to leave the plating layer 12P on the resin frame 22 side. In that case, this step can be skipped. The remaining plating layer 12P functions as a solder guide wall when soldering the light-emitting device 10 to the circuit board.

[0060] Etching of the lead frame 12 at the intersection X forms a rectangular recess 23 (Figure 5) at the corner of the resin frame 22 (Figure 9D).

[0061] Figure 10C shows the removal area RC of the lead frame 12 when forming an arc-shaped recess 23. By removing the intersection X of the lead frame 12 in a circular shape, the end faces 12E at the four corners of the lead can form a recess 23 (Figure 7) having the shape of a cylindrical side surface.

[0062] (S6) Element mounting process Gold-tin (Au-Sn) solder paste is printed onto the component mounting area. Next, the light-emitting element 31 and the protective element 33 are mounted onto the solder.

[0063] The components are mounted by reflow soldering (heating to 300°C) to melt and solidify the gold-tin solder.

[0064] The light-emitting element 31 and the protective element 33 are wire-bonded using gold wire, and the elements are mounted (Figure 9E).

[0065] (S7) Phosphor plate mounting process A transparent adhesive silicone resin is applied to the light-emitting surface of the light-emitting element 31. Next, the phosphor 32 is mounted onto the light-emitting element 31. Then, the resin is partially cured at 180°C to bond the phosphor 32 (Figure 9E).

[0066] (S8) Coating material filling process Next, a coating resin made of silicone resin containing titanium dioxide particles is filled into the opening 25 of the resin frame 22, and the resin is cured by heating at 150°C for 3 hours to form the coating member 35 (Figure 9F).

[0067] (S9) Singulation process Finally, the material is cut into individual components using a dicer. The light-emitting device 10 is manufactured through the above process (Figure 9G).

[0068] According to the present invention, in the lead frame removal step (S5), the lead frame 12 is cut by etching, and in the individualization step (S9), the lead frame 12 is not cut.

[0069] When the lead frame is cut during the process of separating each light-emitting device, the resin frame may peel off due to the cutting stress applied to the lead frame. However, according to the present invention, since the cut portion of the lead frame 12 is removed in advance, the lead frame 12 and the resin frame 22 do not peel off. Therefore, it is possible to provide a light-emitting device with high die-shear strength and less susceptibility to defects such as wire breakage.

[0070] As described in detail above, the present invention provides a light-emitting device in which delamination between the frame and the lead frame is prevented, the die-shear strength of the solder joint is high, and defects such as wire breakage are less likely to occur. [Explanation of Symbols]

[0071] 10: Light-emitting device 12: Lead frame 12A, 12B: Lead 12E: End face of the lead 22: Resin frame 22A, 22B: Outer surface 22G: Fillet Guard 22H: Bottom surface of the recess 22R: Back surface of resin frame 22 22R1: Outer edge of the 22R on the reverse side 23: Recess 30: Light-emitting element 31: LED 32: Phosphor 35: Covering material 40: Circuit board 45: Solder CL: Cutting line RB: Plating removal section

Claims

1. A plurality of plate-shaped lead electrodes having an upper surface, a lower surface, and an end surface connecting the upper surface and the lower surface, A resin frame is provided so as to fill the gaps between the plurality of lead electrodes and surround the entire outer circumference of the plurality of lead electrodes, and has an opening on its upper side that exposes the plurality of lead electrodes, The semiconductor light-emitting element is mounted on the upper surface of the plurality of lead electrodes exposed from the opening, The resin frame has a recess at its lower corner in which the corner of the lead electrode is exposed internally. The lead electrode is not exposed on the outer surface of the resin frame or on a surface substantially flush with the outer surface, but the back surface and end surface of the corner are exposed inside the recess, and the end surface is positioned set back from the outer surface of the resin frame. A semiconductor light-emitting device wherein, within the recess, a partition wall of the resin frame is formed between the end face of the corner and the outer surface of the resin frame, and a housing portion that functions as a portion for housing a solder fillet is formed by the partition wall and the bottom surface of the resin frame.

2. Within the recess, the end face of the lead electrode is an etched exposed surface in which the core material of the lead electrode is exposed. The semiconductor light-emitting apparatus according to claim 1, wherein the outer surface of the resin frame is a cut surface.

3. The lead electrode has a thin-walled portion on the outer edge, excluding the corner, where the back side of the lead electrode is thinned. The semiconductor light-emitting apparatus according to claim 1, wherein in the thin-walled portion, the edge of the lead electrode is covered with resin from the resin frame.

4. The semiconductor light-emitting apparatus according to claim 3, wherein the recess has a height corresponding to the thickness of the lead electrode in the portion excluding the thin-walled portion.

5. The semiconductor light-emitting apparatus according to claim 4, wherein the back surface of the resin frame has an outer peripheral portion formed to become thinner with a step on the back surface of the resin frame, which is the same surface as the back surface of the lead electrode.

6. The semiconductor light-emitting apparatus according to claim 5, wherein the core material of the lead electrode is a corrosive metal and the surface layer of the lead electrode is a corrosion-resistant metal.

7. The semiconductor light-emitting apparatus according to claim 6, wherein the core material of the lead electrode is a metal containing one or more of copper (Cu), aluminum (Al), and iron (Fe), and the surface layer of the lead electrode is a metal containing one or more of gold (Au), platinum (Pt), palladium (Pd), and rhodium (Rh).

8. The semiconductor light-emitting apparatus according to any one of claims 1 to 3, wherein the end face of the lead electrode exposed in the recess has a rectangular shape.

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