JP2000049382A - Semiconductor light-emitting device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-mounted semiconductor light-emitting device, that can improve material utilization rate by increasing the number of products obtained from an insulation material for substrate, and at the same time can be further miniaturized. SOLUTION: A semiconductor light-emitting device is provided with a reverse side electrode 2 and a surface side electrode 3 that are subjected to pattern formation on the reverse and surface sides of an insulation substrate 1, and a light-emitting device 4 which is mounted to the pattern of the surface electrode 3 by making the electrodes at p and n sides 4b and 4a conduct electricity by Ag paste 5. A hole 1a for conduction for allowing the reverse side electrode 2 to face the side of the surface side electrode 3 penetrates through the substrate 1 and the surface side electrode 3 is buried into the bole 1a for conduction for allowing the surface of the reverse side electrode 2 to conduct electricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device of a surface mount type, and more particularly to a semiconductor light emitting device (hereinafter referred to as "LE").
D) is included in a package including an electrode provided on a substrate on which the semiconductor light-emitting device is mounted, and can be miniaturized, and a method of manufacturing the same.

[0002]

2. Description of the Related Art For example, an image display section of a small electronic device such as a mobile phone or a pager has a small and thin chip type L.
ED is mainly used. The chip LED is provided with a pair of electrodes that are electrically connected to each other on both the front and back surfaces of an insulating substrate, and is mounted with one electrode on the front surface, for example, an n-electrode on the lower surface of the LED being electrically connected, and the p-electrode on the upper surface is connected to the other by a wire. The basic configuration is to bond to the electrodes.

As such a chip LED, there is one described in, for example, Japanese Patent Publication No. Hei 7-93338.
Fig. 2 shows its external view.

In FIG. 5, at both ends of an insulating substrate 51, front electrodes 53 and 54 and back electrodes 5 which are conductively developed on the front and rear sides through through holes 52a and 52b are provided.
5, 56 are formed. One surface electrode 54 extends to the center of the substrate 51 to form a stage 54a, on which the LED element 57 is mounted in a conductive state. A bonding area 53a protruding toward the stage 54a is formed on the other surface electrode 53, and the bonding area 53a and the electrode on the surface side of the LED element 57 are connected to a wire 58.
Bonding. Then, the resin package 59 is removed except for the substantially arc-shaped surface electrodes 53 and 54.
To obtain a chip LED.

When mounting the chip LED on the display section of the electronic device, the back electrodes 55 and 56 are mounted in correspondence with the wiring pattern of a printed wiring board (not shown) provided in the display section, and are conductively fixed by soldering. You. The wiring pattern on the printed wiring board and the LED element 57 are connected by electrodes 53, 54, 55, and 56 on both the front and back surfaces, which are conductive through the through holes 52a and 52b, and blink the LED element 57 based on an image signal. Can be done.

The manufacture of a chip LED having the structure shown in the figure generally follows the following steps.

First, holes are formed at a constant pitch in a flat insulating material serving as a material of the substrate 51, and a metal layer for forming electrodes and through holes is formed on the inside of the holes and on both front and back surfaces connected to the holes. A product formed by plating is prepared. Next, the LED element 57 is placed on the stage 54a.
And bonding the wire 58 to the bonding area 53 a of the surface electrode 53. Then, after mounting the LED elements 57 and bonding the wires 58 on the entire surface of the insulating material, the package 59 is formed by covering the mold and injecting resin. Thereafter, as a final step, the chip LED shown in FIG. 5 is obtained by dicing the surface passing through the center of the hole of the insulating material and the surface sandwiching the electrodes 53 to 56 on the front and back surfaces as a cut surface.

[0008]

However, when dicing in a direction to cut through the hole of the insulating material, the metal layer harder than the insulating material is sheared, so that the shearing load of the dicing saw needs to be relatively large. . For this reason, a thicker dicing saw is used as compared with the case of cutting a resin or an insulating material, and therefore, the cutting width sheared by dicing becomes larger. For this reason,
When obtaining the final product from a flat insulating material, the number of product parts will be reduced corresponding to the loss due to this cutting width,
This also affects the efficiency of use of insulating materials and productivity.

Further, in the conventional example shown in FIG.
No. 3 requires that the bonding area 53a for connecting the wire 58 be expanded in addition to the portion for conducting to the back electrode 55 through the through hole 52a. For this reason, the dimension in the direction in which the surface electrode 54 extending the stage 54a to the center of the substrate 51 and the surface electrode 53 projecting from the bonding area 53a face each other becomes longer.

On the other hand, when bonding the LED element 57 with the wire 58, the wire is often raised in an inverted U-shape in order to prevent the wire 58 from breaking. For this reason, the package 59 is also restricted by the height required for accommodating the wire 58, and it is generally said that there is a limit to the reduction in thickness in the field of chip LEDs.

From the above, according to the conventional structure, the chip L
Both the height direction and the planar shape of the ED are restricted by miniaturization, which affects the versatility of the portable electronic device to be mounted.

As described above, the chip type LED in which the electrodes on the front surface and the back surface are electrically connected by using the through holes is not sufficient in terms of the effective use of the insulating material for the substrate and the product yield. There is a problem in that there is a limit to miniaturization of the device.

The problem to be solved in the present invention is to provide a surface-mounted semiconductor light-emitting device which can increase the number of products obtained from insulating materials for a substrate, improve the material utilization rate, and can further reduce the size. is there.

[0014]

A semiconductor light emitting device according to the present invention comprises an insulating substrate, a back electrode patterned on the back surface of the substrate, a front electrode patterned on the surface of the substrate, and A light-emitting element for mounting the p-side and n-side electrodes in a conductive adhesive on the pattern of the front electrode, and mounting the light-emitting element on the substrate. The front surface electrode is immersed in the inside of the hole for conduction, and is electrically connected to the surface of the back electrode.

In this configuration, the light emitting element and the back surface electrode are electrically connected by using the front surface electrode which is immersed into the conduction hole. Therefore, both the conventional through hole and the bonding area are used as the front surface electrode. Can be carried.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 is an invention comprising an insulating substrate, a back electrode patterned on the back surface of the substrate, a front electrode patterned on the surface of the substrate, A light-emitting element for mounting the p-side and n-side electrodes in conduction with a conductive adhesive on the electrode pattern, and the substrate is provided with a conduction hole that exposes the back surface electrode to the front surface electrode. The surface electrode is immersed inside the conduction hole and is electrically connected to the surface of the back electrode, so that the surface electrode can serve both as a conventional through hole and a bonding area. ,
This has the effect of reducing the size of the entire device.

According to a second aspect of the present invention, the surface electrode immersed in the conductive hole has a cross-sectional shape along the inner peripheral surface of the conductive hole, and is formed by the surface electrode in the conductive hole. 2. The semiconductor light-emitting device according to claim 1, wherein the recessed portion serves as a surplus portion of the conductive adhesive. Even when the amount of the conductive adhesive applied is excessive, the portion is stored in the recessed portion of the conduction hole. This has the effect of preventing leakage to the outside of the package.

According to a third aspect of the present invention, there is provided the semiconductor light emitting device according to the first or second aspect, wherein an outer shape resin package including the light emitting element and the conduction hole is formed integrally with the base material side. There is an effect that the package can be collectively stored inside the package, including a conductive portion with the electrode on the back side.

According to a fourth aspect of the present invention, there is provided the method for manufacturing a semiconductor light emitting device according to the third aspect, wherein the conductive hole is formed in an insulating base material having a back surface copper foil formed on a back surface;
A step of spreading a surface copper foil on the front surface side of the base material and immersing a portion corresponding to the hole for conduction into the introduction hole and joining it to the rear surface copper foil; and Forming a pattern by an etching method, mounting and mounting a light emitting element on the etched pattern of the surface copper foil, and filling the conductive layer including the p-side and n-side electrodes of the light emitting element. Fixing the light emitting element to the substrate side by conducting the light emitting element to the surface copper foil with a conductive adhesive, and sealing the surface side of the substrate including the light emitting element with a light transmitting resin. Dicing the substrate and the copper foil on both the front and back surfaces with a region outside the hole for conduction as a cut surface, including a conductive portion with the electrode on the back surface side. In resin package Sealed such an action can be miniaturized.

According to a fifth aspect of the present invention, in the semiconductor light emitting device according to the fourth aspect, the step of immersing the front surface copper foil in the conduction hole and joining the lower surface copper foil to the rear surface copper foil is performed by a laser melting method. This is a method of manufacturing the device, and since only necessary portions of the electrodes on the front surface and the back surface can be narrowed down so that a welded portion is formed by laser melting, there is an effect that the connection can be easily and accurately performed.

According to a sixth aspect of the present invention, the step of immersing the front surface copper foil in the conduction hole and joining the rear surface copper foil to the rear surface copper foil is performed by a caulking method using ultrasonic pressure bonding. The method of manufacturing a semiconductor light emitting device according to the above, wherein only necessary portions of the electrodes on the front surface and the back surface can be narrowed down so that a welded portion is formed by ultrasonic pressure bonding, so that the connection can be easily and accurately performed. .

According to a seventh aspect of the present invention, the step of immersing the front surface copper foil in the hole for conduction and joining the copper foil to the rear surface copper foil is performed by an electroless copper plating method. This is a method for manufacturing a semiconductor light emitting device, and has an effect that it can be easily manufactured using the conventional plating equipment for manufacturing a printed wiring board as it is without the equipment for laser melting or ultrasonic pressure bonding.

Hereinafter, specific examples of the embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a surface-mount type semiconductor light emitting device of the present invention, and FIG. 2 is an external perspective view thereof.

In FIG. 1, a back electrode 2 is formed on the bottom surface of an insulating substrate 1 and a front electrode 3 electrically connected to the back electrode 2 is formed on the front surface of the substrate 1. The back electrode 2 and the front electrode 3 are made of Ni or Al.
The light emitting element 4 is mounted on the plating layer 3a of the surface electrode 3 by laminating the plating layers 2a and 3a made of the same material.

The light emitting element 4 is made of, for example, GaAlAs or G
It utilizes a semiconductor compound such as aP, and has an n-side electrode 4a on the surface of the crystal growth substrate and a p-side electrode 4b on the surface of the p-type layer. When such a light emitting element 4 is incorporated in an LED lamp, the n-side electrode 4a is mounted on a lead frame and the p-side electrode 4b is assembled with the light emitting direction. In the present invention, the n-side and p-side electrodes 4a, 4b is mounted as a posture facing left and right. Therefore, the light-emitting layer 4c in the junction region between the n-type layer and the p-type layer is formed as a substantially vertical layer, and light from the light-emitting layer 4c is extracted from the upper surface of the light-emitting element 4 in the illustrated position.

The light emitting element 4 mounted on the plating layer 3a of the surface electrode 3 is fixed by an Ag paste 5 in which Ag is mixed as a filler in a conductive adhesive such as a curable resin. The Ag paste 5 is laminated on the surface of the plating layer 3a, and the n-side and p-side electrodes 4a, 4b
, The light emitting element 4 conducts with the back electrode 2 side. Therefore, by mounting the substrate 1 on the surface of a printed wiring board (not shown) of the display device and conducting the back electrode 2 to the wiring pattern, a forward current based on the image information can flow through the light emitting element 4. it can.

Further, the light-emitting element 4 including the light-emitting element 4 fixed by the Ag paste 5 is sealed with a light-transmitting resin, and this resin sealing is made into a package 6 by molding to form a surface-mounted semiconductor light emitting element. A device is obtained.

Here, in the semiconductor light-emitting device of the present invention, the substrate 1 on which the light-emitting element 4 is mounted is provided with a pair of conduction holes 1a at a portion sandwiching the light-emitting element 4. This conduction hole 1a is intended to have the same role as the through hole in the conventional example of FIG. That is, as is apparent from FIG. 1, the surface electrode 3 is immersed in the conduction hole 1a, and the lower end thereof is superimposed on the surface of the back electrode 2 to conduct electricity.
Can be conducted.

The Ag paste 5 is applied to both left and right sides of the light emitting element 4. At this time, the application amount and the area of the Ag paste 5 are properly controlled. However, if the application amount is insufficient, the light emitting element 4 becomes unstable and the electrical conduction is hindered. Therefore, it is preferable to increase the application amount. . However,
If the coating amount is too large, the Ag paste 5 may protrude from the edge of the package 6 when dicing,
The influence on the assembly is large, and there is also a risk of short-circuiting when the product is mounted on a printed wiring board and commercialized.

On the other hand, in the present invention, since the conductive holes 1a are formed in the substrate 1, the excess Ag paste 5 flows into the conductive holes 1a, and the leakage of the Ag paste 5 to the edge side of the substrate 1 is suppressed. Can be Therefore, a short circuit is prevented without being exposed from the package 6, and the contact area with the plating layer 3a is increased, so that stable fixing of the light emitting element 4 and reliable conduction with the surface electrode 3 can be obtained.

Further, since the light emitting element 4 is wirelessly bonded, the height can be reduced as compared with the conventional structure shown in FIG. Further, in the conventional structure, it is necessary to provide the electrode with both a through hole for conduction with the electrode on the back side and a bonding area for wire bonding. On the other hand, in the present invention, the conduction hole 1a
The penetrated front surface electrode 3 and its plating layer 3a have both functions of wire bonding (application of the Ag paste 5 in the present invention) and conduction with the back surface electrode in the conventional structure.
Therefore, the bulk occupied by the bonding area and the through hole can be significantly reduced, and the overall size can be reduced.

FIGS. 3 and 4 are schematic views sequentially showing the steps of manufacturing the semiconductor light emitting device of the present invention, and show the steps until one LED chip is obtained.

In FIG. 3 (a), a material in which a back surface copper foil 12 is laminated on the bottom surface of an insulating base material 11 in a wafer state is prepared as an initial material. Then, the conduction holes 11a are made to penetrate the base material 11 at an arrangement pitch corresponding to the size of the chip LED to be manufactured. These conduction holes 1
1a is formed only on the base material 11, and the back surface copper foil 12 located at the lower end thereof is left as it is. The base 11 may be prepared by previously forming the conductive holes 11a before attaching the rear surface copper foil 12, and the conductive holes 11a may be formed by machining.

After the formation of the conduction holes 11a, the surface copper foil 13 is covered as shown by the dashed line in FIG. At this time, it is preferable that the surface copper foil 13 is not subjected to a strong tension, and that the surface copper foil 13 falls into the conduction hole 11a and is slightly bent at a portion covering the conduction hole 11a. .

Next, as shown in FIG. 3C, the surface copper foil 13 is immersed so as to be narrowed down in all the conducting holes 11a. In this step, utilizing the ductility of the copper of the surface copper foil 13, processing is performed so as to uniformly polymerize from the entire inner peripheral surface of the conduction hole 11 a to the surface of the back surface copper foil 12 located at the bottom thereof. I do. In this step, the portion of the surface copper foil 13 immersed in the conduction hole 11a is joined to the back surface copper foil 12, and the back surface copper foil 12 and the surface copper foil 13 are electrically connected.

Here, the step of immersing the surface copper foil 13 into the conduction holes 11a can be performed by a laser melting method, a caulking method using ultrasonic pressure bonding, or can be performed by an electroless plating method. It is. The caulking method using laser melting or crimping using ultrasonic waves has been conventionally used in the field of manufacturing electronic components, but is suitable for manufacturing the semiconductor light emitting device of the present invention. In addition, since the electroless plating method is generally provided in the manufacture of a semiconductor light emitting device, it can be said that it is preferable in that it is not necessary to incorporate a new line.

After the front surface copper foil 13 is immersed in the conduction hole 11a and bonded to the back surface copper foil 12 by any one of the above three methods, a part of the back surface copper foil 12 and a part of the front surface copper foil 13 are etched. Removed by method. The portion to be etched is a pair of conduction holes 11a as shown in FIG.
It is the central region of the portion sandwiched between the. Then, as shown in FIG. 3E, after this etching, the plating layers 12a, 1 are formed on the respective surfaces of the back copper foil 12 and the front copper foil 13 using Ni or Al using a photomask.
3a is formed.

The steps up to this point are performed by a processing operation on the base material 11 in a wafer state.
The process proceeds to the mounting and dicing process of the light emitting element indicated by.

FIG. 4A shows a step of mounting the light emitting element 4 on the base material 11 side. The light emitting element 4 straddles the surface copper foil 13 on the front side of the base material 11 and the portion where the plating layer 13a is removed by etching. 4 is mounted. That is, the n-side electrode 4a faces the conduction hole 11a on the right side, and the p-side electrode 4b positions and mounts the light emitting element 4 so as to face the conduction hole 11a on the left side.

Next, as shown in FIG. 2B, the Ag paste 5 is filled so as to include the n-side and p-side electrodes 4a and 4b. At this time, as described above, the Ag paste 5 is applied not only to the surface of the plating layer 13a but also to the conduction holes 1.
1a immersed surface copper foil 13 and its plating layer 13a
, But the surplus Ag paste 5 stays in this immersed portion. Thereby, the light emitting element 4 is electrically connected to the surface copper foil 13 via the plating layer 13a and is fixed to the base material 11.

When the process of conducting and fixing all the light emitting elements 4 on the base 11 is completed, the wafer of the base 11 is moved from the mounting stage of the light emitting elements 4 to the mold device for resin sealing. Then, by injecting the molten resin into the mold and releasing it after curing under pressure, the package 6 made of a light-transmitting resin is formed as shown in FIG.

Next, as a final step, a cut surface indicated by a dashed line (c) in the same figure and a cut surface orthogonal thereto are diced by a dicer. In this dicing, it is a matter of course that the cut shape is such that the light emitting element 4 is located at the center of the package 6. Then, all of the conduction holes 11a surrounding the light emitting element 4 are included in the package 6 formed as shown in FIG.

Through the above steps, one surface-mounted semiconductor light emitting device shown in FIG. 1 is obtained. The base material 11 and the conduction hole 11a described with reference to FIGS. 3 and 4 are formed as the substrate 1 and the conduction hole 1a in FIG. 1, respectively, and the back copper foil 12, the front copper foil 13, and the plating layers 12a and 13a are formed. Are the back electrode 2, the front electrode 3, and the plating layers 2a, 3 respectively.
a.

[0044]

According to the present invention, as compared with the conventional electrode structure having a through hole and a bonding area, the surface electrode is immersed in the conduction hole provided in the insulating substrate, and the conduction to the back surface electrode on the back side is achieved. Therefore, the planar shape of the substrate can be reduced. In addition, since the light emitting element is also conductively fixed by a conductive adhesive as wireless bonding, the height dimension can be suppressed, and thus the entire light emitting device including the resin package can be significantly reduced in size.

Further, since the recess formed by the conductive hole can be used as a surplus portion of the excess conductive adhesive, even if the adhesive is applied excessively by mistake, it does not leak out of the package and the product yield is reduced. improves.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a semiconductor light emitting device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the appearance of the semiconductor light emitting device of FIG. 1;

FIG. 3 is a schematic view showing a manufacturing method of the present invention, in which steps from a base material to formation of a plating layer are sequentially shown.

FIG. 4 is a schematic view showing a process subsequent to the process of FIG. 3 from mounting of the light emitting element to commercialization by dicing.

FIG. 5 is an external perspective view of a conventional surface mount type semiconductor light emitting device.

DESCRIPTION OF SYMBOLS 1 Substrate 1a Conducting hole 2 Back electrode 2a Plating layer 3 Front electrode 3a Plating layer 4 Light emitting element 4a n side electrode 4b p side electrode 4c Light emitting layer 5 Ag paste 6 Package 11 Base material 11a Conducting hole 12 Back copper foil 12a Plating layer 13 Front copper foil 13a Plating layer

Claims (7)

[Claims] 1. An insulating substrate, a back electrode patterned on the back surface of the substrate, a front electrode patterned on the front surface of the substrate, and a p-side conductive pattern on the pattern of the front electrode. And a light-emitting element for mounting the n-side electrode in a conductive state. The substrate is provided with a through-hole through which the back electrode faces the front electrode, and the front electrode is provided inside the conductive hole. A semiconductor light emitting device which is immersed in the semiconductor device and is electrically connected to the surface of the back electrode. 2. A surface electrode immersed in the conductive hole has a cross-sectional shape along an inner peripheral surface of the conductive hole, and a recess formed by the surface electrode in the conductive hole is formed of the conductive adhesive. 2. The semiconductor light-emitting device according to claim 1, wherein the semiconductor light-emitting device serves as a surplus portion of the semiconductor light-emitting device. 3. The semiconductor light emitting device according to claim 1, wherein an outer shape resin package including the light emitting element and a conduction hole is formed integrally with the base material side. 4. The method for manufacturing a semiconductor light emitting device according to claim 3, wherein: (1) a step of forming the conduction hole in an insulating substrate having a back surface copper foil formed on a back surface; A step of spreading a surface copper foil on the front surface side of the base material, immersing a portion corresponding to the hole for conduction into the introduction hole, and joining to the rear surface copper foil, (3) the rear surface copper foil and the front surface A step of forming a pattern on each of the copper foils by an etching method; (4) a step of mounting and mounting a light emitting element on the etched pattern of the surface copper foil; and (5) a p-side and an n-side of the light emitting element. A step of conducting the light emitting element to the surface copper foil by a conductive adhesive filled with electrodes and fixing the light emitting element to the base material side; and (6) a step of forming a surface side of the base material including the light emitting element. (7) a step of sealing with a light-transmitting resin; Dicing the base material and the copper foils on the front and back surfaces with a region outside the conduction hole as a cut surface. 5. The method for manufacturing a semiconductor light emitting device according to claim 4, wherein the step of immersing the front surface copper foil in the conduction hole and joining the same to the rear surface copper foil is performed by a laser melting method. 6. The method for manufacturing a semiconductor light emitting device according to claim 4, wherein the step of immersing the front surface copper foil in the conduction hole and joining the same to the rear surface copper foil is performed by a caulking method using ultrasonic pressure bonding. . 7. The method of manufacturing a semiconductor light emitting device according to claim 4, wherein the step of immersing the front surface copper foil in the conduction hole and joining the same to the rear surface copper foil is performed by an electroless copper plating method.