JP3022049B2 - Mounting method of light emitting diode of chip component type - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting method capable of mounting an extremely small and thin chip component type light emitting diode on the surface of a wiring board without using a bonding wire.

[0002]

2. Description of the Related Art Light emitting diodes are used as backlights of display panels and liquid crystal display devices, indicators of portable equipment, illumination switches, light sources of OA equipment, and the like. I have. In this light emitting diode, the electrode 22 on the lower surface of the light emitting diode 21 is adhered to the tip of one end 26 of a pair of lead terminals facing each other with a gap with a conductive paste 24, and the electrode 2 on the upper surface is formed.
3 is connected to the tip of the other lead terminal 27 by a gold wire 25 as a bonding wire, and the same is arranged in the longitudinal direction as shown in FIG. It was done. In this example, the left lead terminal 27 is a cathode and the right lead terminal 26 is an anode. The length L, width W, and height H of the product are L = 2.9 mm, W = 1.5 mm, and H, respectively. = 1.1 mm, and the distance between the light emitting diodes is 0.8 mm. Then, the light emitting diode made by molding is mounted by mounting each lead terminal 26, 27 on a wiring pattern on a wiring board (not shown) and soldering them.

[0003]

However, the above-mentioned conventional light emitting diode has one of two lead terminals projecting upward.
6, the lower electrode 22 of the light emitting diode chip 21 is adhered to the tip of the light emitting diode chip 21.
7 and molded in the resin 28 to protect the gold wire 25 and the like from external force, the height of the chip itself is only 0.2 to 0.3 mm, but the height of the entire product However, as described above, it is about three times as large as 1.1 mm, and a considerable space is required on the wiring board. Further, since there are many constituent members, there is a problem that the material cost and the processing cost are increased and the cost of the product is increased.

Accordingly, an object of the present invention is to improve the structure of the light emitting diode chip itself so that an extremely small and thin chip component type light emitting diode can be formed on the surface of the wiring board without using a bonding wire and with a brazing material. It is an object of the present invention to provide a mounting method of a chip component type light emitting diode which can be mounted without supplying the light emitting device and can reduce the cost.

[0005]

According to a first aspect of the present invention, there is provided a mounting method of mounting a chip component type light emitting diode on a surface of a wiring board. A chip component type light emitting diode having a brazing material coating layer on the surfaces of the positive and negative electrodes provided on the end surfaces of the chip is arranged such that the brazing material coating layer on the chip end surface is placed on the wiring pattern of the wiring board. Then, the brazing material coating layer is melted by heating, and the electrode portion on the end face of the chip and the wiring pattern of the substrate are electrically connected only by the melted brazing material.

According to a second aspect of the present invention, the positive and negative electrode portions on the end face of the chip are provided on both end faces of the chip in parallel with the PN junction surface and facing each other.

[0007]

In the light emitting diode mounting method according to the first aspect, the positive and negative electrode portions on the end face of the chip of the light emitting diode are placed on the wiring pattern of the wiring board, and the brazing material coating layer on the surface of both electrode portions is formed. The electrode portion and the wiring pattern are electrically connected only by the molten brazing material, which is melted by heating. Therefore, the size of the light emitting diode can be reduced to a size substantially equal to that of the chip itself, and the thickness can be reduced. In addition, since it is not necessary to separately supply a brazing material, the connection operation can be performed easily, quickly, and with high accuracy.

In the method for mounting a light emitting diode according to the present invention, since the positive and negative electrode portions are provided on both end surfaces of the chip facing each other, the light emitting diode is mounted on both ends by a brazing material which is a molten coating layer. Thus, the light emitting diode can be securely and firmly fixed to the wiring board.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1A is a perspective view showing an example of a method for mounting a chip component type light emitting diode according to claim 2 of the present invention. This light emitting diode has a P-type layer 1 and an N-type layer 2 joined to each other, and a P-type layer and an N-type layer
P-type and N-type electrode portions 3 and 4 provided in parallel with the N junction surface and opposed to each other, and solder coating layers 5 and 6 as brazing materials provided on the surfaces of the electrode portions 3 and 4; It consists of a coating layer 7 (see FIGS. 2C and 2D) of an insulating resin as an insulating material provided on the surface of the four side surfaces other than the coating layers 5 and 6, and has a rectangular parallelepiped shape.

The light emitting diode having the above structure is mounted on a wiring board as follows. That is, as shown in FIG. 1A, the light emitting diode chip is turned sideways, and the solder coated electrode portions 3 and 4 at both ends are connected to the wiring board 8.
It is placed vertically on the upper and lower wiring patterns 9a and 9b, and the center of the bottom coated with the insulating resin is temporarily fixed to the wiring substrate 8 with an adhesive 10. Next, when the wiring board 8 is put into a reflow furnace heated to a temperature equal to or higher than the melting point of the solder, FIG.
As shown in (B), the solders 5, 6 of the electrode portions 3, 4 at both ends are melted, and the soldering of the electrode portions 3, 4 and the wiring patterns 9a, 9b is performed respectively. The light emitting diode is shown in FIG.
Lead terminals 26, 27, bonding wires 25, molding resin 2 protruding from the wiring board as in the conventional example described in
8, the dimensions are reduced to substantially the dimensions of the element chip itself, so that the device can be reduced in size and thickness. In addition, the bonding wire does not break due to external force or thermal stress. This is alleviated by the insulating resin coating layer 7, so that the reliability of the mounted light emitting diode is improved. In addition, the connection work to the wiring pattern can be performed easily, quickly and with high precision, and there is no need to supply solder by screen printing of cream solder, etc., which reduces material and processing costs due to a reduction in the number of parts. Thus, the cost of the mounting operation can be reduced.

FIG. 2 shows an example of a method for manufacturing the light emitting diode. The light emitting diode is mounted on the wafer 11
After the P-type and N-type electrode portions 3 and 4 formed on the front and back surfaces of the light emitting diode in the state are covered with solder to provide solder coating layers 5 and 6, as shown in FIG. , N-side solder coating layer 6 is placed on sheet 12 and attached. Next, as shown in FIG. 2 (B), the wafer 11 is diced vertically and horizontally to separate each chip, and as shown in FIG. 2 (C), the upper surface of each chip is masked with a sheet 13 and the side of each chip is cut. An insulating resin for protection is injected from the direction and cured to form the coating layer 7 on the side surface. Finally, FIG.
As shown in (D), when the sheet on the upper surface is removed, each chip is completed.

According to the above-described manufacturing method, the coating of the P-type and N-type electrode portions 3 and 4 with the solder and the coating of the side surfaces with the insulating resin can be performed collectively in the state of the wafer 11, and the conventional wire bonding is performed. Since no resin mold is required, an extremely small and thin light emitting diode of a chip component type can be manufactured at low cost. In the above-mentioned embodiment, the brazing material for coating the electrode portions 3 and 4 is solder, but it can be another brazing material having a relatively low melting point. The coating layer 7 on the side surface of the chip is not limited to the insulating resin of the embodiment, but may be ceramic, glass or the like as long as it is an insulating material. May be provided only on one side face facing the. Further, the masking sheet 13 on the upper surface of FIG. 2C may be a resist film that does not react with the insulating material of the coating layer 7. Alternatively, the masking sheet 13 may be omitted, and the insulating resin may be formed in the groove formed by dicing. To form the coating layer 7 on the side surface of the chip. In the above-described embodiment, the case where the positive and negative electrode portions 3 and 4 are provided at both ends of the chip of the light emitting diode has been described. However, the positive and negative electrode portions are not limited to this, and are described in claim 1. Thus, for example, either one may be provided on the end face of the intermediate step portion of the chip.

FIG. 3A is a perspective view showing another example of a chip component type light emitting diode. In this light emitting diode, the same two chips as described with reference to FIG. 1A are joined together by a solder coating layer 6 provided on the surface of the N-type electrode portion 4, and extend in a direction orthogonal to the PN junction surface. It is a long chip. Therefore, the same members as those described with reference to FIG.

In the light emitting diode, as shown in FIG. 3B, the chip is turned sideways, and the solder-coated electrode portions 3, 3 at both ends are connected to one and the other wiring pattern 9a, 9b, the central solder-coated electrode portions 4, 4 are placed vertically on the intermediate wiring pattern 9c, respectively, and both sides of the bottom portion coated with insulating resin are temporarily fixed to the wiring substrate 8 with adhesives 10, 10. . Next, when the wiring board 8 is put into a reflow furnace heated to a temperature not lower than the melting point of the solder, as shown in FIG. The solder 6 between the electrodes 4 and 4 is melted and these electrode portions and the wiring pattern 9 are melted.
a, 9b, 9c are soldered. As in the embodiment described with reference to FIG. 1, the light emitting diode does not have the bonding wire 25 (see FIG. 6) and the molding resin 28 as in the conventional example, so that its size is reduced to substantially the size of the element chip itself, and the size is reduced. Thinner and thinner, the connection to the wiring pattern can be done easily, quickly, with high accuracy, and the material cost due to the reduced number of parts,
The cost of the mounting operation can be reduced together with the reduction of the processing cost.

FIG. 4 shows an example of a method for manufacturing the light emitting diode described with reference to FIG. In the light emitting diode, first, P and N type electrode portions 3 and 4 corresponding to the front and back surfaces of the wafer are respectively coated with solder to provide solder coating layers 5 and 6, and then two wafers 11 and 11 are manufactured. Then, the two wafers are superimposed on each other with solder coating layers 6 and 6 and joined together in a reflow furnace or the like to form an integrated wafer 14, and as shown in FIG. Put on and paste. Next, FIG.
As shown in FIG. 3B, the wafer 14 is diced vertically and horizontally to separate each chip. Further, as shown in FIG. 3C, a resist layer 15 is formed on the upper surface of each chip by coating, and from the side direction of each chip. An insulating resin for protection is injected and cured to form a coating layer 7 on the side surface. Finally, as shown in FIG. 3D, each chip is completed by removing the resist layer 15 on the upper surface. The circuit diagram of this light-emitting diode is as shown in FIG. 5A. For example, if one is red and the other is green, a two-color display light-emitting diode can be formed.

In the above manufacturing method, the coating of the electrodes on the front and back surfaces of the two light emitting diode wafers with solder, the superposition of the two wafers, and the coating of the side surfaces of the chips separated by dicing with the insulating resin are performed. It can be performed in a batch in the state of a wafer, and furthermore, the conventional wire bonding and resin molding become unnecessary, and no solder is supplied to the joining of the electrode parts including the central electrode parts 4 and 4, so that it is extremely small and thin. Chip-part series-connected light-emitting diodes can be manufactured at low cost. If the above-described two-color display light-emitting diode is taken as an example, its length L, width W,
The height H is L = 0.5mm, W = 0.3mm, H = 0.3mm,
In comparison with the L, W, and H of the conventional example shown in FIG.
/ 3. In the above embodiment, the intermediate electrode portions 4 and 4 were joined by solder as a brazing material. However, when it is not necessary to connect the electrode portions 4 and 4 to the wiring pattern 9c, a conductive material is used between the electrode portions. May be joined. Also,
As described in the embodiment of FIG. 2, the brazing material for coating the electrode portions at both ends is a low melting point brazing material other than solder, and the coating layer on the side surface of the chip is an insulating material such as ceramic or glass, and only one side surface is used. May be coated. Further, the resist layer 15 on the upper surface may be replaced with a masking sheet. These may be omitted, and an insulating material may be dropped on the dicing groove to coat the side surface of the chip.

FIGS. 5B to 5E are circuit diagrams showing various modifications of the series-connected light emitting diodes produced by the above-described manufacturing method. In these figures, of the connection points of the respective light emitting diode elements, those with the terminal indication are joined by a brazing material such as solder, but the other points need only be joined by a conductive material.

[0018]

As is apparent from the above description, claim 1
The mounting method of the chip component type light emitting diode is a chip component type light emitting diode having a brazing material coating layer on the surfaces of the positive and negative electrodes provided on the end surface of the chip in parallel with the PN junction surface. Disposing the brazing material coating layer on the chip end face on the wiring pattern of the wiring board, melting the brazing material coating layer by heating, and using only the melted brazing material, the electrode portion on the chip end face and the substrate Since it is electrically connected to the wiring pattern of the present invention, conventional bonding wires and molding resin are not used, so that the dimensions can be substantially reduced to the dimensions of the element chip itself, so that the size and thickness can be reduced. Reliability is improved, and the connection work to the wiring board pattern can be done easily, quickly and accurately without the supply of solder etc. , Coupled with the reduction of processing costs,
The cost of the mounting operation can be reduced.

In the method of mounting a light emitting diode according to the second aspect of the present invention, since the positive and negative electrode portions are provided on the opposite end surfaces of the chip, the light emitting diode is mounted on both ends by a brazing material which is a molten coating layer. Thus, the light emitting diode can be securely and firmly fixed to the wiring board.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a method for mounting a light emitting diode according to claim 2 of the present invention.

FIG. 2 is a view illustrating a method of manufacturing the light emitting diode of FIG. 1;

FIG. 3 is a perspective view showing another example of a chip component type light emitting diode.

FIG. 4 is a view illustrating a method of manufacturing the light emitting diode of FIG. 3;

FIG. 5 is a circuit diagram showing various modifications of the light emitting diode of FIG. 3;

FIG. 6 is a plan view and a front view showing a conventional light emitting diode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... P type layer, 2 ... N type layer, 3 ... P type electrode part, 4 ... N type electrode part, 5,6 ... Coating layer of solder, 7 ... Coating layer of insulating resin, 8 ... Wiring board, 9a, 9b, 9c: wiring pattern, 10: adhesive, 11, 14: wafer, 12, 1
3 ... sheet, 15 ... resist layer.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-49284 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 33/00

Claims (2)

(57) [Claims] In a mounting method for mounting a chip component type light emitting diode on a surface of a wiring board, a brazing filler metal is provided on a surface of positive and negative electrode portions provided on an end surface of a chip in parallel with a PN junction surface. A chip component type light emitting diode having a coating layer is disposed such that the brazing material coating layer on the chip end surface is placed on the wiring pattern of the wiring board, and the brazing material coating layer is melted by heating, and the molten brazing material is melted. A method for mounting a light emitting diode of a chip component type, wherein an electrode portion on an end surface of the chip and a wiring pattern on the substrate are electrically connected only by using the light emitting diode. 2. The method according to claim 1, wherein the positive and negative electrode portions on the chip end face are P
2. The method for mounting a chip component type light emitting diode according to claim 1, wherein the light emitting diodes are mounted on both end faces of the chip which face each other in parallel with the N junction surface.