JP2016081959A - Light emission device and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emission device that can enhance the heat radiation performance and the mounting strength based on soldering with neither increasing the size nor complexing the structure.SOLUTION: A light emission device 1 has a board 2 having through-holes 2b, 2c at a position where a light emission element 5 is to be mounted, a metal post 3 having projecting portions 3a, 3b which are fitted in the through-holes 2b, 2c from the back surface side, and electrode portions 3c, 3d projecting to the back surface side of the board 2, and a wiring pattern 4 which is formed on the surface of the board 2 and contacts the projecting portions 3a, 3b. The electrode portions 3c, 3d of the metal post 3 in the light emission device 1 are electrodes which are conducted to the wiring pattern 4 through the projecting portions 3a, 3b. Accordingly, it is unnecessary to provide the metal post and the electrodes separately from each other, and the degree of freedom of the arrangement and shape of the metal post and the electrodes can be enhanced. Furthermore, the thickness and area of the metal post can be increased without increasing the size of the outer shape, and the heat quantity thereof can be increased, so that the heat radiation performance can be enhanced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light emitting device having a substrate structure excellent in heat dissipation and a method for manufacturing the same.

  Conventionally, a light emitting device using a substrate made of an insulating resin or the like has not been provided with a mechanism for releasing heat generated by a light emitting element such as a light emitting diode. In recent years, light emitting elements with high luminance have been used, and heat generated by the light emitting elements has become a problem, and it has become necessary to provide a heat dissipation mechanism. Therefore, a structure for embedding a ceramic core in a position where the light emitting element is mounted on the substrate and dissipating heat to the back side of the substrate is provided, or a base material is laminated on the metal plate, and the protrusion of the metal plate penetrating the base material is provided. It has been proposed to mount a light emitting diode chip at the tip to release heat to the metal plate, or to insert a metal body into the through hole of the insulating base and provide a mounting portion for the light emitting element on the metal body. (For example, refer to Patent Documents 1 to 3).

JP 2002-368277 A JP 2003-69083 A JP 2006-128265 A

  In each of the above conventional light emitting devices, a heat radiation portion is embedded or laminated on a substrate on which a wiring pattern for mounting a light emitting element and an electrode for connection to the outside are formed. For this reason, the position of the wiring pattern and the electrode, and the shape and size of the heat dissipation portion are mutually limited, and there is a problem that it is difficult to reduce the size if the heat dissipation portion is increased in order to improve heat dissipation.

  Also, in order to improve the mounting strength by soldering, it is necessary to optimize the position of the electrode and increase the area of the electrode in contact with the solder, but the heat dissipation part is located on the lower surface or side of the substrate For this reason, it is difficult to change the position and shape of the electrodes, and there is a problem that the structure becomes complicated and the structure becomes large, such as providing a plurality of through holes.

  The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art, and to improve the heat dissipation and the mounting strength by soldering without increasing the size and the structure, and the manufacturing method thereof Is to provide.

  The light-emitting device of the present invention includes a light-emitting element, a substrate having a through hole at a position where the light-emitting element is mounted, a convex portion that fits into the through-hole of the substrate from the back surface side, and an electrode that protrudes from the back surface side of the substrate A metal post having excellent thermal conductivity, and a wiring pattern formed on the surface of the substrate so as to contact a convex portion of the metal post and to mount the light emitting element. The electrode portion is an electrode that conducts to the wiring pattern via the convex portion.

  The wiring pattern in the light emitting device includes a die bonding pattern for die bonding the light emitting element and a wire bonding pattern for wire bonding the light emitting element, and the metal post includes the die bonding pattern and a wire bond. It consists of two separate and independent metal posts each having a convex part that contacts the pattern for use and an electrode part that protrudes at the same height on the back side of the substrate.

  Moreover, the convex part of the said metal post in this light-emitting device has a diameter larger than the convex part which contacts the said pattern for wire bonds, and the convex part which contacts the said pattern for die bonding.

  Furthermore, the side surface of the electrode portion of the metal post in this light emitting device is a slope inclined so that the electrode portion becomes smaller downward.

  In the method for manufacturing a light emitting device according to the present invention, a plurality of through holes are formed at a light emitting element mounting position of a substrate, and a plurality of convex portions are formed on a plate-like metal post so as to correspond to the through hole of the substrate. The metal plate is fixed on the metal post so that the convex portion fits into the through hole, and metal foil is fixed to the surface of the substrate and the back surface of the metal post, respectively, and etching is performed. Dividing the metal post on the foil and the back side, forming wiring patterns and electrodes that are electrically connected through the projections, respectively, on the front and back surfaces of the substrate, and mounting the light emitting element on the wiring pattern on the front side of the substrate To do.

  In the light emitting device of the present invention, the metal post that dissipates the heat of the light emitting element is used as the electrode, so that it is not necessary to provide the metal post and the electrode separately, and the degree of freedom of arrangement and shape of the metal post and the electrode is increased. be able to. Thereby, the thickness and area | region of a metal post can be increased and the thermal capacity can be increased without enlarging an external shape, and heat dissipation can be improved.

  In addition, since the degree of freedom of the arrangement and shape of the metal posts and electrodes is high, the shape and thickness of the electrode portions of the electrode posts located on the back side of the substrate are appropriately set so that the heat radiation is improved and suitable for soldering. It can be formed and the mounting strength by solder can be increased.

  Furthermore, since the side surface of the electrode portion of the metal post is a slope inclined so that the electrode portion becomes smaller in the downward direction, a short circuit due to contact of solder between the electrode portions hardly occurs.

It is a perspective view which shows the light-emitting device which concerns on one Embodiment of this invention. It is sectional drawing of the light-emitting device shown in FIG. It is sectional drawing which shows the state before the perforation | boring of the board | substrate shown in FIG. It is sectional drawing which shows the state which formed the through-hole in the board | substrate shown in FIG. It is sectional drawing which shows the plate-shaped metal post used as the base material of the metal post shown in FIG. It is sectional drawing which shows the state which formed the convex part in the metal post shown in FIG. It is sectional drawing which shows the state which fixed the board | substrate shown in FIG. 4, and the metal post shown in FIG. It is sectional drawing which shows the state which fixed metal foil to the surface of the board | substrate shown in FIG. 7, and the back surface of a metal post. It is sectional drawing which shows the state which etched the board | substrate and metal post shown in FIG. 8, and formed the wiring pattern and the electrode in the front and back.

  The light emitting device 1 shown in FIGS. 1 and 2 includes a substrate 2 and a metal post 3. The substrate 2 is a film or a thin plate made of insulating alumina, resin or the like, and in this embodiment, a conductive layer 2a used in forming a wiring pattern is formed on the surface in advance. The substrate 2 is provided with through holes 2b and 2c at positions where the light emitting elements are mounted. The through holes 2b and 2c in the present embodiment are respectively provided at a position where the light emitting element is die-bonded and a position where the light-emitting element is wire-bonded, and the through-hole 2b on the die bond side is larger in diameter than the through-hole 2c on the wire bond side. Is formed.

  In the present embodiment, the metal post 3 is made of a metal plate having excellent thermal conductivity such as copper and having conductivity, and is composed of two independent metal posts 3A and 3B. The metal posts 3A and 3B are provided with convex portions 3a and 3b that fit into the through holes 2b and 2c, respectively, and electrode portions 3c and 3d that protrude to the back side of the substrate 2. Similarly to the through holes 2b and 2c, the convex portions 3a and 3b are formed such that the convex portion 3a on the die bond side is larger in diameter than the convex portion 3b on the wire bond side. The electrode portions 3c and 3d are formed on the back side of the substrate 2 so as to protrude at the same height. Furthermore, the side surfaces 3e and 3f of the electrode portions 3c and 3d are inclined surfaces so that the electrode portions 3c and 3d become smaller downward. In addition, metal layers 3g and 3h such as copper foil are provided on the back surfaces of the electrode portions 3c and 3d in the present embodiment, and further, the gold portions are covered so as to cover the side surfaces 3e and 3f of the electrode portions 3c and 3d and the metal layers 3g and 3h. Surface layers 3i and 3j made of silver plating or the like are provided.

  The wiring pattern 4 formed on the surface of the substrate 2 has a die-bonding pattern 4A for die-bonding the light-emitting element and a wire-bonding pattern 4B for wire-bonding the light-emitting element. The die bonding pattern 4A and the wire bonding pattern 4B are formed so as to block the through holes 2b and 2c of the substrate 2, respectively. The die bond pattern 4A and the wire bond pattern 4B in the present embodiment are a metal layer 4a made of copper foil or the like that comes into contact with the protrusions 3a and 3b of the metal posts 3A and 3B that are fitted to the through holes 2b and 2c from the back side. , 4b and surface layers 4c, 4d made of gold, silver plating or the like covering the surfaces of the metal layers 4a, 4b, respectively. Note that the metal layers 4 a and 4 b overlap with a part of the pattern formed by the conductive layer 2 a provided on the surface of the substrate 2, thereby conducting to other patterns provided on the substrate 2.

  The light emitting element 5 made of a light emitting diode or the like is die-bonded on the die-bonding pattern 4 </ b> A of the wiring pattern 4 and wire-bonded to the wire-bonding pattern 4 </ b> B by the wire 6.

  The sealing resin 7 is made of an epoxy resin, a silicon resin, or the like, and seals the light emitting element 5 and the wire 6. The sealing resin 7 may be mixed with a phosphor as necessary.

  In the light emitting device 1 having the above configuration, the substrate 2 and the metal post 3 are fixed by the adhesive layer 8 so that the convex portions 3a and 3b of the metal post 3 fit into the through holes 2b and 2c of the substrate 2 from the back side. Yes. In this state, the wiring pattern 4 formed on the substrate 2 comes into contact with the projections 3a and 3b of the metal post 3, so that heat generated by the light emitting element 5 is transmitted to the metal post 3 via the wiring pattern 4, and the metal post 3 radiates heat. Further, since the wiring pattern 4 on the substrate 2 is in contact with the convex portions 3a and 3b of the metal post 3, the wiring pattern 4 and the metal post 3 are electrically connected, thereby connecting the electrode portions 3c and 3d of the metal post 3. It becomes possible to use as an electrode for this purpose.

  As described above, by using the metal post 3 as the heat radiating portion and the electrode, it is necessary to provide a structure in which the wiring pattern 4 is routed on the side surface or the back surface of the substrate 2 or a through hole is provided to conduct to the electrode provided on the back surface side. Disappears. Thereby, the area | region which provides the metal post 3 can be increased, without enlarging the board | substrate 2, and it becomes possible to enlarge the metal post 3 easily and to improve a heat capacity and heat dissipation.

  Further, in this embodiment, the metal post 3A and its convex portion 3a through which heat of the light emitting element 5 is transmitted through the die bonding pattern 4A are made larger in diameter than the other metal post 3B and its convex portion 3b. In this way, the heat capacity is increased to increase heat dissipation. The metal post 3B radiates the heat of the wire bond pattern 4B and the substrate 2 accompanying the heat generation of the light emitting element 5, so that there is no functional problem even if the heat capacity is smaller than that of the metal post 3A.

  On the other hand, in the light emitting device 1, the electrode portions 3c and 3d of the metal posts 3A and 3B that are electrically connected to the die bonding pattern 3A and the wire bonding pattern 3B are brought into contact with a conductive portion (not shown) such as a circuit board. It is mounted by fixing with solder. At this time, the electrode portions 3c and 3d protrude greatly at the same height on the back surface side of the substrate 2, and the side surfaces 3e and 3f are inclined, so that they are below the substrate 2 along the side surfaces 3e and 3f. Solder can be applied so as to enter, and the mounting strength can be increased by increasing the amount of solder and the state of the solder can be easily confirmed visually. Further, since the electrode portions 3c and 3d are reversely tapered, there is an advantage that short-circuiting due to contact between the solders hardly occurs when the electrode portions 3c and 3d are fixed by soldering.

  Next, a method for manufacturing the light emitting device 1 will be described with reference to FIGS. First, as shown in FIGS. 3 and 4, through holes 2b and 2c are provided in a substrate 2 on which a conductive layer 2a is formed in advance. The positions where the through holes 2b and 2c are provided are positions where the light emitting element 5 is die-bonded and wire-bonded. In addition, although it is preferable to change the magnitude | size of the through-holes 2b and 2c as shown in FIG. 2, as shown in FIG. 4, the same magnitude | size may be sufficient.

  Further, as shown in FIGS. 5 and 6, the plate-like metal post 3 is formed with convex portions 3 a and 3 b that fit into the through holes 2 b and 2 c of the substrate 2.

  After that, as shown in FIG. 7, an adhesive layer 8 such as an adhesive is provided on the back surface of the substrate 2 or the surface of the metal post 3, and the convex portions 3 a of the metal post 3 are inserted into the through holes 2 b and 2 c from the back surface side of the substrate 2. 3b is fitted and fixed.

  Here, as shown in FIG. 8, a metal foil 9 such as a copper foil serving as a prototype of the metal layers 4 a and 4 b is attached to the surface of the substrate 2. At this time, in the present embodiment, the metal foil 10 serving as a prototype of the metal layers 3g and 3h is also attached to the back surface of the metal post 3 serving as an electrode.

  Thereafter, as shown in FIG. 9, the metal foils 9 and 10 and the metal post 3 are formed and divided by etching or the like, and the metal layers 4a and 4b of the wiring pattern 4 and the electrode portions 3c and 3d of the metal post 3 are formed. To divide the metal post 3 into two independent metal posts 3A and 3B. At this time, the side surfaces 3e and 3f of the electrode portions 3c and 3d are formed on the inclined surfaces, but they are flush with the side surfaces of the substrate 2 without being inclined like the side surface 3f shown in FIG. You may make it become. Furthermore, in the present embodiment, the surface layers 4c, 4d, 3i, and 3j are formed by plating or the like so as to cover the surfaces of the metal layers 4a, 4b, 3g, and 3h and the electrode portions 3c and 3d.

  As described above, the light emitting device 5 is mounted on the formed substrate 2 and sealed with the sealing resin 7 to complete the light emitting device 1.

  In such a manufacturing method of this embodiment, since the substrate 2 and the metal post 3 are processed in a bonded state, the substrate has high strength, is not easily damaged, and is easy to handle. Further, the front and back surfaces of the substrate 2 and the metal post 3 can be formed by simply performing the same processing at the same time, and can be completed with fewer manufacturing steps.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Board | substrate 2a Conductive layer 2b, 2c Through-hole 3 Metal post 3A, 3B Metal post 3a, 3b Convex part 3c, 3d Electrode part 3e, 3f Side surface 3g, 3h Metal layer 3i, 3j Surface layer 4 Wiring pattern 4A Die bond Pattern 4B Wire bond pattern 4a, 4b Metal layer 4c, 4d Surface layer 5 Light emitting element 6 Wire 7 Sealing resin 8 Adhesive layer 9, 10 Metal foil

Claims (5)

A light emitting element;
A substrate having a through hole at a position where the light emitting element is mounted;
A metal post excellent in thermal conductivity having a convex portion that fits into the through hole of the substrate from the back surface side, and an electrode portion that protrudes from the back surface side of the substrate;
A wiring pattern that is formed on the surface of the substrate and is in contact with the convex portion of the metal post, and on which the light emitting element is mounted,
The light emitting device according to claim 1, wherein the electrode portion of the metal post is an electrode that is electrically connected to the wiring pattern through a convex portion. The wiring pattern has a die-bonding pattern for die-bonding the light-emitting element and a wire-bonding pattern for wire-bonding the light-emitting element,
The metal post is composed of two separate and independent metal posts each having a convex portion that contacts the die bond pattern and the wire bond pattern and an electrode portion that protrudes at the same height on the back side of the substrate. The light emitting device according to claim 1.   3. The light emitting device according to claim 2, wherein the convex portion of the metal post has a diameter larger than that of the convex portion in contact with the wire bonding pattern.   The light emitting device according to claim 2, wherein the side surface of the electrode portion of the metal post is a slope inclined so that the electrode portion becomes smaller downward. A plurality of through holes are formed at the light emitting element mounting position of the substrate,
A plurality of convex portions are formed on the plate-like metal post so as to correspond to the through holes of the substrate,
Fixing the substrate on the metal post so that the convex portion fits into the through hole;
A metal pattern is fixed to the front surface of the substrate and the back surface of the metal post, and etching is performed to divide the metal foil and the metal post on the back surface side, and a wiring pattern that conducts through the convex portions, respectively. Forming electrodes on the front and back surfaces of the substrate,
A method for manufacturing a light emitting device, comprising mounting a light emitting element on a wiring pattern on a surface side of the substrate.

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