JP2002057374A - Semiconductor light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a short with no interference between conductive bonds when a light-emitting element is mounted and fixed on a substrate and a lead frame using the conductive bond. SOLUTION: A flip chip semiconductor light-emitting element 1 is mounted on a mounting surface, and a side opposite to the mounting surface side is taken as a main light take-out surface with continuity through the electrodes on a p-side and an n-side of the semiconductor light-emitting element 1. Conductive bonds 10a and 10b are applied on the mounting surface as separate spots for bonding the electrodes on the p-side and the n-side or micro bumps 4 and 5 formed to them. An insulating spacer resin 11 is so provided as to run between the applied points of the conductive bonds 10a and 10b for blocking interference between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip type semiconductor light emitting device using a gallium nitride compound used for an optical device such as a blue light emitting diode, and more particularly, to a light emitting element mounted on a mounting surface thereof. The present invention relates to a semiconductor light emitting device in which a short circuit due to a conductive adhesive for bonding is not sometimes prevented.

[0002]

2. Description of the Related Art GaN, GaAlN, InGaN and I
In the production of gallium nitride based semiconductors such as nAlGaN, insulating sapphire is generally used as a crystal substrate for growing a semiconductor film on the surface. When an insulating crystal substrate such as sapphire is used, electrodes cannot be provided from the crystal substrate side, so that the p and n electrodes provided on the semiconductor layer are formed on one surface facing the crystal substrate. become.

For example, a light-emitting device using a GaN-based compound semiconductor uses a sapphire substrate as an insulating substrate, and forms an n-type layer and a p-type layer on the sapphire substrate by metal organic chemical vapor deposition to form a p-type layer. Etch part of the layer to n
The basic configuration is that the mold layer is exposed and an n-side electrode and a p-side electrode are formed on each of the n-type layer and the p-type layer. If the p-side electrode is a transparent electrode, bonding pads are formed on these p-side and n-side electrodes, respectively, and wire-bonded to a lead frame or a substrate.

On the other hand, in a flip-chip type semiconductor light emitting device in which light is extracted from the sapphire substrate,
A configuration is adopted in which micro-bumps are formed on each of the p-side and n-side electrodes without making the side electrodes transparent, and these micro-bumps are connected to the p-side and n-side of the substrate or lead frame. .

FIG. 5 is a longitudinal sectional view schematically showing an LED lamp using a flip-chip type semiconductor light emitting device.

In FIG. 1, a light-emitting element 1 includes, for example, a GaN buffer layer, an n-type GaN layer, an InGaN active layer, and a p-type AlGa on a surface of an insulating transparent sapphire substrate 1a.
An N layer and a p-type GaN layer are sequentially stacked, and an InGaN active layer is used as a light emitting layer. Then, an n-side electrode 2 is formed on the upper surface of the n-type GaN layer, and a p-side electrode 3 is formed on the upper surface of the p-type GaN layer by a vapor deposition method. Have micro bumps 4 and 5, respectively.

The mount 6a of the lead frame 6 on which the light emitting element 1 is mounted is provided with a Zener diode 7 as an electrostatic protection element in order to prevent external application of static electricity to the light emitting element 1 and to prevent its destruction. The Zener diode 7 is bonded and fixed to a mount 6a with a conductive Ag paste 8, and has p-side and n-side electrodes 7a and 7b formed on the upper surface thereof.

The light emitting element 1 is mounted on the Zener diode 7 with the sapphire substrate 1a facing upward, and the n-side and p-side micro bumps 4 and 5 are respectively joined to the electrodes 7a and 7b of the Zener diode 7. In this way, electrical conduction is achieved. And lead frame 6
The entire light emitting element 1 including the upper end portion is sealed with the epoxy resin 9 to form an LED lamp having the shape shown in the figure.

When the light emitting element 1 is energized, the InGaN active layer in the semiconductor laminated film becomes a light emitting layer, and light from this light emitting layer travels in both directions of the sapphire substrate 1a and the p-side electrode 3. By forming the p-side electrode 3 as a reflective laminated film that does not transmit light, the sapphire substrate 1a
This surface can be used as the main light extraction surface by maximizing the light emission luminance from the upper surface.

In mounting the light emitting element 1 on such a Zener diode 7, it is necessary to conduct the micro bumps 4 and 5 and the electrodes 7a and 7b, for example, by using a thermocompression bonding method or a bonding method using an adhesive. Is performed.

In the example shown, a conductive adhesive using an Ag paste or the like is used. On the upper surfaces of the electrodes 7a and 7b, conductive adhesives are previously provided at two positions corresponding to the positions of the micro bumps 4 and 5. By applying the agents 10a and 10b and polymerizing the micro-bumps 4 and 5 thereon, the light-emitting element 1 can be fixed to the upper surface of the Zener diode 7 and electrically connected.

[0012]

However, since the conductive adhesives 10a and 10b have a certain degree of fluidity until they are cured, even if they are applied separately to the electrodes 7a and 7b, When the light emitting element 1 is placed and fixed, the conductive adhesives 10a and 10b in these two regions may come into contact with each other.

That is, when mounting the light emitting element 1 on the Zener diode 7, the micro bumps 4 and 5 are press-fitted into the layers of the conductive adhesives 10a and 10b, respectively. 10a and 10b are deformed so as to be expanded at the same time as being compressed. If such deformation is excessive, the conductive adhesives 10a and 10b come into contact with each other and cause a short circuit.

When the light emitting element 1 is mounted, if the mounting direction is orthogonal to the Zener diode 7 with high accuracy, only the force acting to compress the conductive adhesives 10a and 10b acts. And the amount of deformation can be kept small. However, if the light emitting element 1 is placed in an oblique direction or is displaced for some reason after being mounted, the conductive adhesives 10a, 10b
However, there is a high possibility that large deformation will occur with this. And
Even in the case of such a deformation, the conductive adhesive 10
a and 10b are brought into contact with each other to cause a short circuit.

As described above, in the case where the flip-chip type light emitting element 1 is fixed to the Zener diode 7 by the conductive adhesives 10a and 10b, the conductive adhesives 10a and 10b are deformed when the light emitting element 1 is mounted. Frequent short circuits occur. The same problem occurs not only when the light emitting element 1 is mounted on the zener diode 7 but also when, for example, the light emitting element 1 is mounted on a lead frame or a substrate and fixed by a conductive adhesive.

The problem to be solved in the present invention is to provide an assembly which can prevent the occurrence of a short circuit without interference between the conductive adhesives when mounting and fixing the micro-bumps of the light emitting element to a substrate or a lead frame with the conductive adhesive. It is to be.

[0017]

According to the present invention, a flip-chip type semiconductor light emitting device is mounted on a mounting surface of a substrate such as a substrate or a lead frame, and the semiconductor light emitting device is mounted on its p-side and n-side electrodes. In the semiconductor light emitting device having the main light extraction surface on the side opposite to the mounting surface side of the semiconductor light emitting element, a conductive adhesive for bonding the p-side and n-side electrodes is provided on the mounting surface. Independently applied in a spot manner, the conductive adhesive is arranged between application points, and is formed by forming an insulating spacer resin for preventing mutual interference. .

According to this configuration, even if the conductive adhesive is deformed so as to be spread when the light emitting element is placed on the mounting surface of the base material, the insulating property is maintained between the application points of the conductive adhesive. Since the spacer resin is interposed, the conductive adhesives do not come into contact with each other, and a short circuit is prevented.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a flip-chip type semiconductor light emitting device is mounted on a mounting surface of a substrate such as a substrate or a lead frame, and the semiconductor light emitting device is mounted on its p-side and n-side. In the semiconductor light emitting device having the main light extraction surface on the side opposite to the mounting surface side of the semiconductor light emitting element, the p-side and the n-side
The conductive adhesive for bonding the side electrodes is applied in spots independently of each other, and it is arranged between these conductive adhesive application points to prevent mutual interference. The spacer resin is formed, and the insulating spacer resin is interposed between the application points of the conductive adhesive, so that the conductive adhesives do not come into contact with each other and a short circuit is prevented. Has an action.

The invention according to claim 2 is characterized in that the p-side and n-side
A micro-bump was integrally formed on the electrode on the side, and the micro-bump was bonded to the substrate with the conductive adhesive including the micro-bump, and the micro-bump was formed on the p-side and the n-side of the semiconductor light emitting device. In any case, the contact between the conductive adhesives is prevented by the spacer resin. The provision of the micro-bumps can increase the distance between the p-side and n-side electrodes and the base material side, and has an effect that a short circuit can be more effectively prevented.

According to a third aspect of the present invention, the spacer resin is made of a fluorine-based resin, and has an effect of repelling the conductive adhesive by water repellency of the fluorine-based resin to prevent mutual interference. Have.

Hereinafter, specific examples of the embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded schematic view of a light emitting element and a zener diode of a semiconductor light emitting device according to an embodiment of the present invention, in which main parts are exploded. The light emitting element and the Zener diode have the same form as that shown in FIG.
The same members are indicated by common reference numerals, and detailed description thereof will be omitted.

The light emitting element 1 has an n-side electrode pad 2a and a p-side electrode pad 3a arranged diagonally on the surface opposite to the main light extraction surface, and micro bumps 4 and 5 are respectively formed by wires on these. It is formed by a stud bump method.

The Zener diode 7 is formed by dividing a p-side electrode 7a and an n-side electrode 7b on the upper surface with a slit 7c interposed therebetween. Then, on the surfaces of the p-side and n-side electrodes 7a, 7b, conductive adhesives 10a, 10b using, for example, Ag paste are applied to regions corresponding to the positions of the micro bumps 4, 5, respectively. . Then, in the area along the slit 7c, p
An insulating spacer resin 11 is formed like the boundary between the n-side electrodes 7a and 7b.

The spacer resin 11 is a water-repellent fluorine-based resin, and can be formed into the shape shown in the drawing if it is patterned in the state of a wafer when the zener diode 7 is manufactured. In this patterning, the spacer resin 11 is immersed in the entire slit 7c and, as shown in the plan view of FIG. 2, covers the surfaces of the p-side and n-side electrodes 7a and 7b along the slit 7c. It is preferable to be thicker and thicker than the conductive adhesives 10a and 10b.

FIG. 3 is a schematic view showing a state where the light emitting element 1 is mounted on the zener diode 7 and fixed.

The n-side and p-side micro bumps 4 and 5 of the light emitting element 1 are connected to the p-side and n-side of the Zener diode 7, respectively.
Are mounted on the side electrodes 7a and 7b,
a, 7b are immersed in the conductive adhesives 10a, 10b applied thereto. At this time, the n-side and p-side electrode pads 2a, 3a of the light emitting element 1 are simultaneously connected to the conductive adhesives 10a, 10a.
Thus, the n-side and p-side electrode pads 2a and 3a and the respective micro bumps 4 and 5 come into contact with the electrodes 7a and 7b, and the light emitting element 1 and the Zener diode 7 conduct.

When the light emitting element 1 is mounted, the conductive adhesives 10a and 10b are spread and deformed in a direction approaching each other as described in the section of the prior art. On the other hand, the spacer resin 11 is used for the conductive adhesive 1.
0a and 10b, it interferes with the deformation of the conductive adhesives 10a and 10b. Therefore, the deformation of the conductive adhesives 10a and 10b is prevented by the spacer resin 11 and is prevented from coming into contact with each other.

When the spacer resin 11 is made of a fluorine-based resin, the water-repellency is large, so that the conductive adhesives 10a, 1
Even if Ob is deformed to swell greatly, the deformed portion can be repelled by water repellency. Therefore, contact between the conductive adhesives 10a and 10b can be more effectively prevented.

Further, by providing the spacer resin 11, even if the application positions of the conductive adhesives 10a and 10b are shifted or the amount of application is too large, mutual interference can be avoided. Therefore, there is no need for an assembly that strictly limits the accuracy and amount of application of the conductive adhesives 10a and 10b, and the processing is facilitated.

Further, in the illustrated example, the conductive adhesive 10
a and 10b are separated into p-side and n-side electrodes 7a and 7b,
Although the coating is performed at the individual portions, the coating may be performed in such a manner that the coating is superimposed on the surface of the spacer resin 11 formed in advance in the wafer manufacturing stage. In this case, when the light emitting element 1 is mounted and pressure-bonded, if an assembly is provided at an interval between the spacer resin 11 and the Zener diode 7 such that the spacer resin 11 slightly compressively deforms in the thickness direction, the pressure is applied to the spacer resin 11 by pressing. The conductive resin is extruded toward the p-side and n-side electrodes 7a and 7b. Then, even if the conductive resin remains on the surface of the spacer resin 11, the layer thickness is extremely thin or the distribution is minutely scattered, so that it is not sufficient for electrical conduction, thereby preventing a short circuit. .

FIG. 4 shows that the n-side electrode pad 2a and the p-side electrode pad 3a are connected to the p-side and n-side electrodes 7a and 7b of the Zener diode 7 by the conductive adhesives 10a and 10b without forming the micro bumps 4 and 5, respectively. It is a longitudinal cross-sectional view of the principal part which shows the example bonded directly.

This example is different from the previous example only in that the micro bumps 4 and 5 are not formed, and the other configuration is the same. The same members are designated by the same reference numerals as those shown in FIGS.

Even if the micro bumps 4 and 5 are not formed,
If the conductive adhesives 10a and 10b are formed to have an appropriate thickness, it is possible to provide an assembly without unnecessary short circuit between the semiconductor light emitting element 1 and the Zener diode 7 side. Then, as in the previous example, by interposing the spacer resin 11 between the conductive adhesives 10a and 10b, a short circuit between the p-side and the n-side is reliably prevented.

In the above embodiment, an example is shown in which the light emitting element is mounted on a Zener diode. However, it goes without saying that the present invention can be applied to a case where the light emitting element is mounted on a lead frame or a substrate.

[0037]

According to the first and second aspects of the present invention, since the insulating spacer resin is interposed between the points where the conductive adhesive is applied, the conductive adhesive is placed on the mounting surface of the light emitting element. Even if the application area of the agent is expanded to expand, the spacer resin can interfere with this and prevent mutual contact,
Short circuits can be reliably prevented. In addition, the short circuit can be prevented without strictly controlling the position and amount of the conductive adhesive to be applied, thereby facilitating the assembly.

According to the third aspect of the present invention, since the conductive adhesive can be repelled by the water repellency by using the fluorine resin as the spacer resin, the short circuit can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and is a schematic diagram showing an exploded view of a light emitting element and a Zener diode.

FIG. 2 is a plan view of a Zener diode showing distribution of a spacer resin and a conductive adhesive.

FIG. 3 is a front view showing a relationship between a spacer resin and a conductive resin when the light emitting element is mounted on the Zener diode.

FIG. 4 is a longitudinal sectional view of a main part showing an example in which electrodes are directly joined with a conductive adhesive without forming micro-bumps on p-side and n-side electrodes of a semiconductor light emitting device.

FIG. 5 shows a conventional L-type chip having a flip-chip type light emitting element.
Schematic vertical sectional view of an ED lamp

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light emitting element 1 a sapphire substrate 2 n-side electrode 2 a n-side electrode pad 3 p-side electrode 3 a p-side electrode pad 4, 5 microbump 6 lead frame 6 a mount 7 Zener diode 7 a, 7 b electrode 8 Ag paste 9 epoxy resin 10 a 10b Conductive adhesive 11 Spacer resin

Claims (3)

[Claims] A flip-chip type semiconductor light emitting device is mounted on a mounting surface of a substrate such as a substrate or a lead frame, and the semiconductor light emitting device is electrically connected to p-side and n-side electrodes thereof. In the semiconductor light emitting device having the main light extraction surface on the side opposite to the mounting surface side, a conductive adhesive for bonding the p-side and n-side electrodes is spot- A semiconductor light emitting device in which an insulating spacer resin that is applied and arranged between application points of these conductive adhesives to prevent mutual interference is formed. 2. The method according to claim 1, wherein a microbump is formed integrally with the p-side and n-side electrodes, and the p-side and n-side electrodes are bonded to the base material with the conductive adhesive including the microbump.
14. The semiconductor light emitting device according to claim 1. 3. The semiconductor light emitting device according to claim 1, wherein the spacer resin is a fluorine resin.