JP2003046142A - Light emitting device and support base used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a short circuit accident across electrodes caused by an adhesive. SOLUTION: The light emitting device is composed of a light emitting element 2 provided with a pair of electrodes 4, 5 on one face, and a support base 3 whose surface is provided with a pair of electrodes 7, 8 to which the pair of electrodes 4, 5 are fixed. Grooves 9, 10 which are situated between the pair of electrodes 7, 8 are formed on the surface of the support base 3. The grooves can be formed as the pair of grooves 9, 10 corresponding to the pair of electrodes 7, 8. The grooves can be formed as mutually independent grooves. The grooves are arranged to be mutually parallel, and they can be arranged on a straight line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device in which a light emitting element is mounted on a supporting base by a flip chip method and a supporting base thereof.

[0002]

2. Description of the Related Art In general, a light emitting device using an insulating substrate such as a gallium nitride based semiconductor light emitting device using a sapphire substrate as a substrate has p and n electrodes arranged on one surface thereof (Japanese Patent Laid-Open No. Hei 10 (1999) -242977). 10-256184, etc.). A support for fixing the light emitting element by the flip chip method has a pair of p and n electrodes electrically connected to the p and n electrodes on the upper surface. Then, the light emitting device is assembled by fixing the light emitting element to the support with an electrically conductive adhesive such as solder interposed between the p and n electrodes of the support and the p and n electrodes of the light emitting element. .

However, there is a problem that the conductive adhesive in a fluidized state may diffuse so as to connect between the p and n electrodes, which causes a short circuit of the electrodes.

[0004]

Therefore, one of the objects of the present invention is to prevent the occurrence of the above-mentioned short circuit between the electrodes. Another object is to prevent enlargement of the element shape by widening the electrode interval as a countermeasure against short circuits.

[0005]

As described in claim 1, a light emitting device of the present invention has a light emitting element having a pair of electrodes on one surface and a pair of electrodes to which the pair of electrodes are fixed. In the light-emitting device including the support table provided in step 1, a groove located between the pair of electrodes is formed on the upper surface of the support table.

As described in claim 2, the light emitting device of the present invention comprises a light emitting element having a pair of electrodes on one surface and a support base having a pair of electrodes on the upper surface to which the pair of electrodes are fixed. In the above light emitting device, a pair of grooves corresponding to the pair of electrodes are formed on the upper surface of the support base.

As described in claim 3, the light emitting device of the present invention comprises a light emitting element having a pair of electrodes on one surface, and a support base having a pair of electrodes on the upper surface to which the pair of electrodes are fixed. According to another aspect of the present invention, at least two independent grooves are formed between the pair of electrodes on the upper surface of the support.

According to a fourth aspect of the present invention, there is provided a support base for supporting a light emitting device, comprising a pair of electrodes on an upper surface of the support base, wherein a groove located between the pair of electrodes is formed on the upper surface. Is characterized by.

According to a fifth aspect of the present invention, there is provided a support base for supporting a light emitting device, comprising a pair of electrodes on an upper surface, wherein a pair of grooves corresponding to the pair of electrodes are formed on the upper surface. It is characterized by

According to a sixth aspect of the support base of the present invention, in the support base having a pair of electrodes on the upper surface, at least two independent grooves are formed between the pair of electrodes on the upper surface. It is characterized by

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a light emitting device 1 according to a first embodiment of the present invention, and FIG. 2 is a plan view of a main part (support base) of FIG. Note that FIG. 1 is a sectional view taken along the line AA of FIG.

The light emitting device 1 comprises a light emitting element 2 and a chip type support 3 for fixing the light emitting element 2 by a flip chip method and having a larger area than the light emitting element. The light emitting element 2 is provided with a pair of electrodes of a p-type electrode 4 and an n-type electrode 5 on one surface. As the light emitting element 2, for example, a gallium nitride based light emitting element as shown in FIG. 6 can be used. That is, the GaN buffer layer 21, the n-type GaN semiconductor layer 22, the n-type GaAlN cladding layer 23, the InGaN active layer 24, the p-type GaAlN cladding 25, and the p-type GaN contact layer 26 are laminated on the sapphire substrate 20, and p
-Type GaN contact layer 26 with Au-based p-type electrode and n-type G
The light emitting element 2 can be configured by providing an Al-based n electrode on the aN semiconductor layer 22 layer. As the light emitting element, a light emitting element having a configuration other than the above may be used as long as it has a pair of electrodes on one surface.

The support base 3 is provided with a pair of thin film type electrodes 7 and 8 on one surface (upper surface) of a base material 6 and a chip type in which a plurality of grooves 9 and 10 are arranged between the electrodes 7 and 8. It is composed of elements. As the base material 6, a semiconductor substrate, an insulating substrate, a metal substrate subjected to an insulating treatment, or the like can be used. Here, the case of using a semiconductor substrate will be described as an example.

The base material 6 of the support base 3 is composed of a semiconductor substrate made of an n-type Si (silicon) substrate. For example, an n-type Si substrate having a resistivity of 500 Ωcm, a thickness of 200 μm and a (100) surface is prepared, and a silicon oxide film (SiO 2) 11 is formed on the surface. The silicon oxide film 11 is first formed by thermal oxidation.

Next, the silicon oxide film 11 on one surface is selectively removed by photolithography, and anisotropic wet etching is performed using the remaining silicon oxide film 11 as a mask to expose it from the silicon oxide film 11. The Si layer is etched. By this etching, the grooves 9 and 10 having a depth of about 3 μm are formed.

Further, for surface protection, a vapor phase growth method (CV
A silicon oxide film (SiO2) is formed on the entire surface by D). In the silicon oxide film 7 of FIG. 1, a thick film portion shows a portion where both the thermal oxidation film and the CVD film exist, and a thin film portion has the thermal oxidation film removed so that only the CVD film. It shows the remaining part.

Then, Cr is formed on the silicon oxide film 11.
An electrode material composed of (chrome) / Au (gold) or the like is formed into a film,
By removing unnecessary portions of the electrode material by photolithography, a pair of electrodes 7 and 8 for the support base corresponding to the p and n electrodes 4 and 5 are formed on one surface (upper surface) of the support base 3. To do.

After the electrodes are formed, the semiconductor substrate is divided into a predetermined chip size so that a plurality of support bases 3 can be formed from one semiconductor substrate.

The electrodes 7 and 8 are set to have a sufficiently larger area than the electrodes 4 and 5 of the light emitting element 2, and the electrodes 4 and 5 of the light emitting element 2 are set.
In order to accommodate both the case where 5 is located in the center of the opposite sides of the light emitting element 2 and the case where it is located in the diagonal direction of the light emitting element 2, it is equivalent to the two opposite sides of the light emitting element. It is formed over the length range.

In the light emitting element 2, the p and n electrodes 4 and 5 are
It is attached to the support base 3 by being fixed to the corresponding electrodes 7 and 8 of the support base 3 using a conductive adhesive 12, 12 such as solder or silver paste.

The grooves 9 and 10 formed on the upper surface of the support base 3 are
The upper surface of the support base is divided into three regions, that is, two regions with the electrodes 7 and 8 and one region between the electrodes 7 and 8 in parallel with each other between the electrodes 7 and 8. Therefore, when the adhesive 12 in a fluidized state flows out from the electrodes 7 and 8, the grooves 9 and 10 receive the adhesive 12 that has flowed out and act to prevent further diffusion.

Since the grooves 9 and 10 are arranged corresponding to the electrodes 7 and 8, one groove 9 should receive the adhesive flowing out from the electrode 7, and the other groove 10 should receive the adhesive flowing out from the electrode 8. Therefore, it is possible to prevent the adhesive 12 flowing out from the electrodes 7 and 8 from fusing together. That is, it is possible to prevent the occurrence of an accident in which the electrodes 7 and 8 are short-circuited by the adhesive 12.

As described above, since the two independent parallel grooves 9 and 10 are arranged between the electrodes 7 and 8, the electrodes 4 and 5 of the light emitting element 2 are arranged as shown in FIG. Not only when the adhesives 12 are arranged at the central portions of the opposite sides but also when they are arranged in the diagonal direction of the light emitting element 2 as described later, the individual adhesives 12 that have flowed out are surely prevented from flowing into the grooves 9,
Can accept 10.

The configuration shown in FIGS. 1 and 2 has a plurality of grooves 9 and 10.
3 shows an example in which the groove is formed so as to completely traverse the upper surface of the support base 3. However, as shown in FIG. 3, each groove 9 and 10 should be formed so as not to completely traverse one surface of the support base. You can also That is, the lengths of the grooves 9 and 10 can be set to be shorter than the length of the side of the support base 3 parallel to the groove 9 (10). Here, it is preferable to set the lengths of the grooves 9 and 10 so that the grooves 9 and 10 have regions overlapping with each other in the width direction in order to effectively prevent the adhesive 12 from flowing out. As shown in FIG. 3, the support base 3 shown in FIG. 3 is effective for mounting the light emitting element 2 in which the p and n electrodes 4 and 5 are arranged in a diagonal direction.

Although the above embodiment shows an example in which the grooves 9 and 10 are formed on the support base 3 so as to be parallel to each other, according to the present invention, as shown in FIG. It can also be applied to the case of arranging in. By arranging the grooves 9 and 10 in this way, the light emitting element 2 in which the pair of electrodes 4 and 5 are arranged in a diagonal direction as shown in FIG.
It is effective in preventing the adhesive 12 from flowing out when the adhesive 12 is mounted on. Also. Since the area occupied by the grooves 9 and 10 is reduced, the dimensions of the support base 3 and the light emitting element 2 can be reduced.

Although each of the above-described embodiments shows an example in which two grooves 9 and 10 are independently formed, the present invention can be applied to the case where three or more independent grooves are formed. This is possible, and as shown in FIG. 5, it can be applied to the case where there is one groove.

As shown in FIG. 5, when there is one groove 9,
If the adhesive flows out from both electrodes 7 and 8 at the same time and they are fused in the groove, the effect cannot be exhibited.
Depending on the material, shape, arrangement, etc. of the electrodes 7 and 8, the adhesive 12 may preferentially flow out from only one electrode. In such a case, even one groove is effective.

In the above embodiment, the case where the grooves 9 and 10 are chemically formed by etching has been exemplified, but the present invention is also the same when the grooves are mechanically formed such as scribe and dicing. Can be applied to.

The portions of the electrodes 7 and 8 which are not covered with the light emitting element 2 are used as regions for connecting the wire bond wires 13.

Further, the support base 3 may be provided with a light receiving element integrally on a part thereof. The light receiving element has a light receiving region arranged on the same surface as the surface on which the electrodes 7 and 8 are formed, and can be used to directly or indirectly receive the light emitted from the light emitting element 2. With this configuration, the light emitting device 1 can have a structure including the light emitting element 2 and the light receiving element.

[0031]

According to the present invention, the conductive adhesive flowing out from the pair of electrodes can be received by the groove provided on one surface of the supporting base, and a short-circuit accident between the electrodes due to the conductive adhesive occurs. Can be prevented. Providing a plurality of grooves can surely prevent the spread of the adhesive. Further, by arranging the grooves in a straight line, the outer shape of the support base and the light emitting device can be downsized.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a main part plan view showing an embodiment of the present invention.

FIG. 3 is a plan view of a main portion showing another embodiment of the present invention.

FIG. 4 is a plan view of a main part showing another embodiment of the present invention.

FIG. 5 is a main part plan view showing another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an embodiment of a light emitting device.

[Explanation of symbols]

1 Light emitting device 2 light emitting element 3 support 4 p-type electrode 5 n-type electrode 6 base material 7 electrodes 8 electrodes 9 grooves 10 grooves 11 Silicon oxide film 12 Adhesive 13 wire bond wire

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5F041 AA25 AA47 CA40 CA46 CA74                       DA02 DA04 DA07 DA09 DA39                 5F044 KK01 LL07 RR18 RR19

Claims (6)

[Claims] 1. A light emitting device comprising a light emitting element having a pair of electrodes on one surface and a support base having a pair of electrodes to which the pair of electrodes are fixed on an upper surface, wherein the pair of electrodes is provided on an upper surface of the support base. A light emitting device characterized in that a groove located between the electrodes is formed. 2. A light emitting device comprising a light emitting device having a pair of electrodes on one surface and a support base having a pair of electrodes to which the pair of electrodes are fixed on the upper surface, wherein the pair of electrodes are provided on the upper surface of the support base. A pair of grooves corresponding to the electrodes of 1. are formed. 3. A light emitting device comprising a light emitting element having a pair of electrodes on one surface and a support base having a pair of electrodes to which the pair of electrodes are fixed on an upper surface, wherein the pair of upper surfaces of the support base are provided. A light emitting device, characterized in that at least two grooves independent of each other are formed between the electrodes. 4. A support base for supporting a light emitting device, which comprises a pair of electrodes on an upper surface, wherein a groove located between the pair of electrodes is formed on the top surface. 5. A support base for supporting a light emitting device, which comprises a pair of electrodes on an upper surface thereof, wherein a pair of grooves corresponding to the pair of electrodes are formed on the upper surface. 6. A support base having a pair of electrodes on an upper surface thereof, wherein at least two independent grooves are formed between the pair of electrodes on the upper surface.