JPH11243230A - Light-emitting diode chip and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small, thin, and low-cost light-emitting diode chip capable of being mounted directly on the surface of a printed circuit board without through a bonding wire. SOLUTION: This light-emitting diode chip comprises a plurality of chips connected by a conductive material or solder 6 in an orthogonal direction of the P-N junction face at a positive and negative electrode sections 3 and 4 formed on both end faces in parallel with the P-N junction face of the chips, and the electrode 3 and 4 of both ends of the connected sequential chip have a solder coating layer 5 on their surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extremely small and thin chip part type light emitting diode which can be directly mounted on the surface of a wiring board without using bonding wires, and a method of manufacturing the same.

[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, an electrode 22 on the lower surface of a light-emitting diode 21 is bonded to the tip of one of a pair of lead terminals 26 facing each other with a gap with a conductive paste 24, and the electrode 23 on the upper surface is bonded to a bonding wire. 6A is connected to the tip of the other lead terminal 27 by a gold wire 25, and the same one is arranged in the longitudinal direction as shown in FIG. 6A, and these are molded in a transparent resin 28. . In this example, the left lead terminal 27 in the figure is a cathode, and the right lead terminal 26 is an anode.
The width W and height H are L = 2.9 mm, W = 1.5 mm, H = 1.1 mm, respectively.
And the distance between the light emitting diodes is 0.8 mm. Then, the light emitting diodes made by molding are connected to respective lead terminals 26 and 27 on a wiring pattern on a wiring board (not shown).
Are mounted, and both are soldered and mounted.

[0004]

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.

Therefore, an object of the present invention is to improve the structure of the light emitting diode chip itself so that it can be directly mounted on the surface of the wiring board without using bonding wires.
An object of the present invention is to provide an extremely small and thin chip component type light emitting diode which can reduce the cost and does not require the supply of brazing material during mounting, and a method for manufacturing the same.

[0006]

In order to achieve the above object, a chip component type light emitting diode according to the first aspect of the present invention can be directly mounted on a surface of a wiring board without using a bonding wire. Plural chips are provided on both ends parallel to the PN junction surface of the chip.
The negative electrode portion is sequentially connected by a conductive material or a brazing material in a direction perpendicular to the PN junction surface, and the electrode portions at both ends of a series of connected chips have a brazing material coating layer on the surface. And

That is, in the light emitting diode according to the first aspect, the surfaces of the electrode portions at both ends of a series of chips formed by sequentially connecting a plurality of chips with a conductive material or a brazing material are coated with a brazing material. Therefore, the size of the light emitting diode can be reduced and reduced to approximately the size of a series of chips themselves. Further, when the electrode portions at both ends of the light emitting diode and the intermediate brazing material connection portion are placed vertically on one, the other and the intermediate wiring pattern on the wiring board, respectively, and heated in a furnace or the like to the melting point of the brazing material or more, The brazing material at both electrode portions and the intermediate connecting portion is melted and soldered to each wiring pattern.

According to a second aspect of the present invention, there is provided the chip component type light emitting diode according to the first aspect, wherein at least one of the side surfaces other than both end surfaces of the series of chips is provided on the surface. It has a coating layer of an insulating material.

According to a second aspect of the present invention, at least one of the side faces other than the both end faces of the series of chips has a coating layer of an insulating material on the surface, so that the side face coated with the insulating material of the light emitting diode has Opposite to the wiring board surface, the electrodes at both ends and the intermediate brazing material connection are placed vertically on one, the other, and the intermediate wiring pattern on the wiring board, respectively, and in a furnace or the like, the melting point of the brazing material or higher is exceeded. When heated, the brazing material at both electrode portions and the intermediate connection portion is melted and soldered to each wiring pattern. Since the external force applied to the chip at the time of mounting is reduced by the coating layer of the insulating material on the side surface, the reliability of the mounted light emitting diode is further improved.

According to a third aspect of the present invention, there is provided a method of manufacturing a light emitting diode, wherein the positive and negative electrode portions provided on the front and rear surfaces of the plurality of light emitting diodes in a wafer state are made of a brazing material or a conductive material. After coating, these wafers are overlapped and joined so that a coating layer of brazing material appears on both end surfaces, and then the overlapped and joined wafers are vertically and horizontally diced.

Therefore, according to the method of manufacturing a light emitting diode according to the third aspect, the front and back electrode portions of the plurality of light emitting diodes in a wafer state are coated with a brazing material or a conductive material, and the brazing materials are formed on both end surfaces. The above-mentioned superposition bonding of a plurality of wafers such that the coating layer appears can be performed collectively in the state of a wafer, and furthermore, since conventional wire bonding and resin molding are not required, an extremely small and thin chip component type is required. Item 1 can be manufactured at a low cost.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a light emitting diode according to the third aspect, wherein the side surface of each chip separated by dicing is coated with an insulating material. It is characterized by doing.

Therefore, according to the method of manufacturing a light emitting diode of the present invention, the coating of the side surface of each chip separated by dicing with the insulating material can be performed collectively in the state of a wafer, so that it is extremely small and thin. The light emitting diode according to the second aspect of the present invention can be manufactured at low cost.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. First, a reference example will be described.

FIG. 1A is a perspective view showing a chip component type light emitting diode of a reference example. This light-emitting diode comprises a P-type layer 1 and an N-type layer 2 joined to each other, and P-type and N-type layers provided at end faces of the P-type and N-type layers 1 and 2 in parallel with a PN junction surface. Mold electrode portions 3, 4; solder coating layers 5, 6 as brazing material provided on the surfaces of the electrode portions 3, 4; and four side surfaces other than the coating layers 5, 6 It consists of a coating layer 7 of an insulating resin as an insulating material (see FIGS. 2C and 2D).
Presenting a rectangular chip.

The light emitting diode having the above configuration 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
Since there is no 8, the size can be reduced to substantially the size of the element chip itself to achieve a reduction in size and thickness, the bonding wire does not break due to external force or thermal stress, and the external force applied to the chip during mounting is This is alleviated by the insulating resin coating layer 7, so that the reliability of the mounted light emitting diode is improved. Furthermore, the connection 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 a method for manufacturing the light emitting diode as a reference example. The light emitting diode,
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 of the wafer 11 are covered with solder to provide solder coating layers 5 and 6, as shown in FIG. Thus, the N-side solder coating layer 6 is placed on the sheet 12 and attached. Next, as shown in FIG. 2 (B), the wafer 11 is diced vertically and horizontally to separate each chip.
As shown in (C), the upper surface of each chip is masked with a sheet 13, and a protective insulating resin is injected from the side surface direction of each chip and cured to form a coating layer 7 on the side surface. Finally, as shown in FIG. 2 (D), if 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 collectively performed 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 reference example, 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. Further, the coating layer 7 on the side surface of the chip is not limited to the insulating resin of the reference example, 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.

Next, an embodiment of the present invention will be described. FIG. 3A is a perspective view showing an embodiment of a chip component type light emitting diode according to claims 1 and 2 of the present invention. 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 5, 5 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 the insulating resin are temporarily fixed to the wiring board 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. Since the light emitting diode does not have the bonding wire 25 (see FIG. 6) and the mold resin 28 as in the conventional example, similarly to the reference example described with reference to FIG. 1, the size of the light emitting diode is reduced to substantially the size of the element chip itself. In addition to reducing the thickness and thickness, the bonding wire does not break due to external force or thermal stress, and the external force applied to the chip during mounting is reduced by the coating layer 7 of the insulating resin on the side surface. Reliability is improved. Furthermore, the connection work to the wiring pattern can be done easily, quickly and with high accuracy, and the material cost due to the reduction in the number of parts,
The cost of the mounting operation can be reduced together with the reduction of the processing cost.

FIG. 4 shows a method of manufacturing the light emitting diode described in FIG. 3 as an embodiment of the manufacturing method according to the third and fourth aspects. In the light-emitting diode, first, P and N-type electrode portions 3 and 4 on the front and back surfaces of the wafer are respectively coated with solder to provide solder coating layers 5 and 6.
After the wafers 11, 11 are manufactured, the two wafers are overlaid on each other with the solder coating layers 6, 6 and joined together in a reflow furnace or the like to form an integrated wafer 14, as shown in FIG. Apply the solder coating layer 5 on the side of sheet 1
Put on 2 and paste. Next, as shown in FIG. 3B, the wafer 14 is diced vertically and horizontally to separate each chip, and as shown in FIG. 3C, a resist layer 15 is formed on the upper surface of each chip by coating. Insulating resin for protection is injected from the side of the chip and hardened to form a coating layer 7 on the side. 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-described manufacturing method, the coating of the electrode portions on the front and rear surfaces of the two light emitting diode wafers with the solder, the overlapping joining 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 connected between the electrode portions. You may join with a material. Also, as described in the reference example 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 of the chip is an insulating material such as ceramic or glass. You may make it coat only a side surface. Further, the resist layer 15 on the upper surface is
It may be replaced with a masking sheet, omitting these,
An insulating material may be dropped on the dicing groove to coat the chip side surface.

FIGS. 5B to 5E are circuit diagrams showing various modifications of the series-connected light emitting diodes according to the first and second aspects of the present invention. ing. 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.

[0024]

As is apparent from the above description, claim 1
In the chip component type light-emitting diode according to the invention described in (1), a plurality of chips are provided in both positive and negative electrode portions provided on both end surfaces parallel to the PN junction surface of the chip, in a direction orthogonal to the PN junction surface. Are sequentially connected by a conductive material or a brazing material, and since the electrode portions on both end surfaces of a series of connected chips have a brazing material coating layer on the surface,
Without conventional bonding wires and molding resin, the dimensions are reduced to the size of a series of chips themselves, miniaturizing,
The thickness can be reduced, the reliability is improved without the risk of breaking the bonding wire, the connection work to the pattern on the wiring board can be done easily, quickly and accurately without the supply of solder etc. The cost of the mounting operation can be further reduced in conjunction with the reduction of the cost and the processing cost.

Furthermore, in the chip component type light emitting diode according to the second aspect of the present invention, at least one of the side surfaces other than both end surfaces of the series of chips has a coating layer of an insulating material on the surface. Since the external force applied to the chip during mounting is reduced by the coating layer of the insulating material on the side surface, the reliability of the mounted light emitting diode is further improved.

According to a third aspect of the present invention, in the method of manufacturing a light emitting diode, the positive and negative electrode portions provided on the front and rear surfaces of the plurality of light emitting diodes in a wafer state are made of a brazing material or a conductive material. After coating, these wafers are overlapped and bonded so that a coating layer of brazing material appears on both end surfaces, and then the overlapped and bonded wafers are diced vertically and horizontally, so that an intermediate coating with brazing material or conductive material and 2. The light-emitting diode according to claim 1, wherein the light-emitting diode according to claim 1 can be coated with the material at both ends in a wafer state, eliminating the need for conventional wire bonding and resin molding, and being extremely small and thin. Can be.

In the method of manufacturing a light-emitting diode according to the present invention, the side surface of each chip separated by the dicing is coated with an insulating material. The light emitting diode according to the second aspect of the present invention can be manufactured at a lower cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a light emitting diode of a reference example.

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

FIG. 3 is a perspective view showing an embodiment of the light emitting diode according to the first and second aspects of the present invention.

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 Solder coating layer 7 Insulating resin coating layer 8 Wiring board 9a, 9b, 9c Wiring pattern 10 Adhesive 11, 14 Wafer 12, 13 sheet 15 resist layer

Claims (4)

[Claims] 1. A light emitting diode of a chip component type which can be directly mounted on a surface of a wiring board without using a bonding wire, wherein a plurality of chips are provided on both end surfaces parallel to a PN junction surface of the chip. In the positive and negative electrode portions, the PN
A chip-part-type light-emitting diode, which is sequentially connected by a conductive material or a brazing material in a direction orthogonal to the bonding surface, and the electrode portions at both ends of a series of connected chips have a brazing material coating layer on the surface. . 2. The chip component type light emitting diode according to claim 1, wherein at least one of the side surfaces other than both end surfaces of the series of chips has a coating layer of an insulating material on the surface. Type light emitting diode. 3. The method for manufacturing a light emitting diode of a chip component type according to claim 1, wherein the positive and negative electrode portions provided on the front and back surfaces of the plurality of light emitting diodes in a wafer state are brazed. Alternatively, after coating with a conductive material, these wafers are overlapped and joined so that a coating layer of a brazing material appears on both end surfaces, and then the overlapped and joined wafers are diced vertically and horizontally, which is characterized by a chip component type. A method for manufacturing a light emitting diode. 4. The method according to claim 3, wherein a side surface of each of the chips separated by dicing is coated with an insulating material. A method for manufacturing a light emitting diode.