JP2003209286A - Light emitting device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable light emitting device with especially high light emitting efficiency capable of emitting light at high luminance regarding the light emitting device utilizing a nitride semiconductor light emitting element. <P>SOLUTION: The light emitting device is provided with a light emitting element having a pair of positive and negative electrodes on the same surface side, and a support having an external electrode separately stacked on an insulating substrate surface. The upper surface of the external electrode is covered with a reflection layer having a through-hole and the respective electrodes of the light emitting element face an external electrode surface exposed from the through-hole through a bump having at least one kind of the same materials as the external electrode. Further, the light emitting device is provided with an external reflection layer mounted on the support, and provided with the through-hole capable of housing the light emitting element and an internal reflection layer composed of the same material as the external reflection layer between the respective electrodes and the external electrode. <P>COPYRIGHT: (C)2003,JPO

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 using a nitride semiconductor light emitting element, and an object of the present invention is to provide a highly reliable light emitting device capable of emitting light with high luminance and high brightness. .

[0002]

2. Description of the Related Art In the case of bonding an LED chip to an external electrode of a support by flip-chip mounting, a new bonding technique using ultrasonic waves has recently appeared and is becoming mainstream. This ultrasonic bonding method is as follows.

First, Au bumps are formed on the conductor of the support placed on the stage.

Next, with the electrode surface of the LED chip having both positive and negative electrodes provided on the same surface side facing downward, the Au bumps are brought into contact with both the positive and negative electrode surfaces of the LED chip containing Au.

Finally, while the external electrodes, the positive and negative electrode surfaces of the LED chip, and the Au bumps are heated, pressure is applied so that the distance between the upper surface of the external electrodes and the LED chip electrode surface is narrowed, Ultrasonic vibration is applied to the electrodes, the positive and negative electrode surfaces of the LED chip, and the Au bumps. At this time, the heat and the frictional heat generated by the ultrasonic vibration melt the contact portion between the Au bump and the support and both the positive and negative electrode surfaces. Stuck to.

In this way, the external electrodes of the support and the positive and negative electrodes of the LED chip are joined via the Au bumps,
Electrical connection between the two is achieved.

Here, flip chip mounting refers to a method in which the electrode surface of a semiconductor chip having both positive and negative electrodes on the same surface side is the lower side and direct surface connection is made to the conductor of the support.

[0008]

However, when a light emitting device is formed using an LED chip that emits light having a short wavelength such as blue light and an Au-plated support, Au is used.
Has a low reflectance for light having a short wavelength, such as blue, and cannot improve the light extraction efficiency. When Ag or the like having high light reflectance is used as the plating material on the support, the Au formed on the Ag-plated portion of the support is used.
Joining the bump and the positive and negative electrodes containing Au of the LED chip is joining between different materials. Therefore, the joining method using ultrasonic waves causes a decrease in the joining strength and a decrease in productivity. It was

[0009]

SUMMARY OF THE INVENTION The present invention provides light emission including a light emitting element having a pair of positive and negative electrodes on the same surface side, and a support having external electrodes separately laminated on the surface of an insulating substrate. In the device, an upper surface of the external electrode is covered with a reflective layer having a through hole, and each electrode of the light emitting element is exposed from the through hole through a bump having at least one kind of material same as the external electrode. The light emitting device is characterized by facing the surface of the external electrode.

With the structure according to claim 1 of the present invention, the electrodes of the light emitting element and the external electrodes are ultrasonically die-bonded through the bumps having at least one kind of the same material, so that the same kind of metal is formed. Since the portions containing the elements are bonded to each other, the bonding strength can be kept high. Further, when a metal that maintains a high reflectance for light having a wavelength shorter than that of blue is used as the material of the reflective layer and the light emitting device emits light having a wavelength shorter than that of blue, the light extraction efficiency can be improved. It is possible.

The invention according to claim 2 is the light-emitting device according to claim 1, wherein the light-emitting element is sealed with a mold member.

With the structure according to the second aspect of the present invention, the light emitting element and the like can be protected from external force from the external environment, dust and water.

According to a third aspect of the present invention, a light emitting element having a pair of positive and negative electrodes on the same surface side, a support having external electrodes separately laminated on the surface of an insulating substrate, and a support on the support are provided. An external reflection layer having a through hole that is placed and capable of accommodating the light emitting element, wherein each electrode of the light emitting element has the through hole through a bump having at least one material that is the same as the external electrode. The light emitting device is characterized in that it has an internal reflection layer made of the same material as the external reflection layer, between the electrodes and between the external electrodes, the internal reflection layer facing the external electrode surface exposed from.

With the structure according to claim 3 of the present invention, when a soft and highly elastic resin such as a silicone resin containing a diffusing agent is molded into a unique shape for use in the present invention as the reflecting layer, Not only can the light extraction efficiency be improved, but also the heat dissipation effect can be improved.

According to a fourth aspect of the invention, there is provided the light emitting device according to the third aspect, wherein the inner wall of the outer reflection layer is tapered and the outer wall of the inner reflection layer is inversely tapered. is there.

With the structure according to claim 4 of the present invention, the outer reflection layer can be brought into close contact with the side surface of the LED chip by only slightly deforming the inner reflection layer.
It is possible to exist without any gap between the positive and negative electrodes of the chip and the external electrodes.

The invention according to claim 5 is the light-emitting device according to any one of claims 3 to 4, characterized in that a mold member is provided inside the external reflection layer.

With the structure according to the fifth aspect of the present invention, it is possible to protect the light emitting element and the like from external force from the external environment, dust and water.

According to a sixth aspect of the present invention, a light emitting element having a pair of positive and negative electrodes on the same surface side, a support having external electrodes separately laminated on the surface of an insulating substrate, and a support on the support are provided. In a method of manufacturing a light emitting device having an external reflection layer having a through hole that is placed and capable of accommodating the light emitting element, a through hole in which a part of each surface of the external electrode is exposed is provided on the support. A first step of forming the reflective layer having a resilient member in a cured state; a second step of forming bumps in the through-holes; and electrodes of the light-emitting element formed of the bumps. And a third step of facing each other and pressing the light emitting element toward the support to electrically connect the light emitting element.

By the method according to claim 6 of the present invention, a member having elasticity in a cured state is molded into a shape unique to the present invention and used as a reflective layer, and the light extraction efficiency and the heat radiation are improved. A light emitting device with improved effect can be easily manufactured. That is, conventionally, it was a very troublesome work to pour a resin or the like between the LED chip and the support without leaving a gap after the LED chip was die-bonded onto the support, but by the method according to the present invention, Workability can be improved by die-bonding the LED chip after the layer is preformed on the support.

According to a seventh aspect of the present invention, the reflective layer comprises:
7. The method for manufacturing a light emitting device according to claim 6, wherein the mold is formed with a mold release agent applied inside.

The method according to claim 7 of the present invention prevents adhesion of the member to the surface of the mold when the mold is removed after curing the elastic member in the cured state. Since the mold surface and the member are easily separated, the reflective layer can be molded with good workability.

[0023]

As a result of various studies, the present inventor has a reflection layer having a through hole and an external electrode exposed from the through hole on the upper surface of the external electrode, and each electrode of the light emitting element is Provided is a light emitting device that does not reduce light extraction efficiency or bonding strength by connecting an external electrode exposed from a through hole via a bump having at least one kind of the same material contained in the external electrode. Made possible. That is,
As shown in FIG. 1, the support used in one embodiment of the present invention is composed of Cu, Ni, A on a glass epoxy resin 111.
The u and Ag layers are sequentially stacked, and have external electrodes formed by being separated by the insulating portion 113. Through holes are provided in the Ag layer 107 used as the reflection layer in this embodiment, and the Au layer 10 is formed by the through holes.
The upper surface of 8 is exposed. Then, in the light emitting device according to the present embodiment, the pair of positive and negative electrodes of the LED chip 100 is bonded (bonded) to the Au layer 108 via the Au bump 106 in the through hole provided in the Ag layer by flip chip mounting. It becomes. Furthermore, the Ag layer 107 is connected to the external wiring 701.

Further, as shown in FIG. 2, the support used in another embodiment of the present invention is such that Cu, Ni and Au layers are laminated in this order on the glass epoxy resin 111, and the insulating portion 113 is used. It has an external electrode formed by being separated. In the light emitting device according to the present embodiment, a pair of positive and negative electrodes of the LED chip 100 are flip-chip mounted to be bonded (joined) to the Au layer 108 via Au bumps, and the resin is highly elastic in a cured state. The external reflection layer 201 composed of the LED chip 1
00, the internal reflection layer 202 is inserted into the gap between the electrode surface of the LED chip and the upper surface of the support. Further, the Au layer 108 is connected to the external wiring 701.

Here, the negative electrode 10 of the LED chip 100 is used.
3 and the positive electrode 104 and the external electrode on the upper surface of the support are bonded by ultrasonic bonding.

Hereinafter, each configuration of the embodiment of the present invention will be described in detail. [LED Chip 100] In the present embodiment, the LED chip 100 is used as the light emitting element in the present invention. Examples of the semiconductor light emitting device used in the present invention include those using various semiconductors such as ZnSe and GaN. When a fluorescent substance is used, a short wavelength that can efficiently excite the fluorescent substance capable of emitting nitride semiconductor _{(In X Al Y Ga 1-} X-Y N, 0
≦ X, 0 ≦ Y, X + Y ≦ 1) are preferable. Examples of the semiconductor structure include a homo structure having a MIS junction, a PIN junction, a pn junction, etc., a hetero structure, and a double hetero structure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal thereof. Further, the semiconductor active layer may be formed as a thin film in which a quantum effect is generated, and may have a single quantum well structure or a multiple quantum well structure.

When a nitride semiconductor is used, materials such as sapphire, spinel, SiC, Si and ZnO are preferably used for the semiconductor substrate. A sapphire substrate is preferably used in order to form a nitride semiconductor having good crystallinity with good mass productivity. MOCVD on this sapphire substrate
A nitride semiconductor can be formed by using a method or the like. A buffer layer of GaN, AlN, GaAlN or the like is formed on a sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.

As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer made of n-type gallium nitride on a buffer layer, and a first clad made of n-type aluminum gallium nitride / gallium. A layer, an active layer formed of indium gallium nitride, a second cladding layer formed of p-type aluminum nitride gallium, and a second contact layer formed by sequentially stacking a second contact layer formed of p-type gallium nitride. Can be mentioned.

The nitride semiconductor exhibits n-type conductivity in a state where it is not doped with impurities. When forming a desired n-type nitride semiconductor such as improving the luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C or the like as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, Zn, Mg, Be, and C which are p-type dopants are used.
Doping with a, Sr, Ba and the like. Nitride semiconductor is p
Since it is difficult to form a p-type by only doping with a type dopant, it is preferable to reduce the resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant.

When an insulating substrate such as sapphire is used as the substrate, both positive and negative electrodes are formed, and then the semiconductor wafer is cut into chips to obtain a nitride semiconductor chip in which both positive and negative electrodes are provided on the same side. Thus, a light emitting element can be formed. Here, by forming the positive and negative electrodes parallel to each other, it is possible to stably mount the support according to the present invention, and the current flowing between the electrodes becomes uniform, so that the light emission from the light emitting surface of the light emitting element becomes uniform. Therefore, it is preferable. [External Electrode 112] The external electrode 112 in the present invention is
It is formed separately on the upper surface of the insulating substrate. Here, the external electrode 112 in the present invention may be formed on the entire upper surface of the insulating substrate, but may be formed in various conductive patterns on a part of the upper surface of the insulating substrate. The metal forming the external electrode 112 is selected in consideration of good adhesion between metals, so-called wettability, and the like. When the electrode of the LED chip containing Au is bonded by ultrasonic die bonding via the Au bump, the bonding layer is an Au layer. Here, the bonding layer is one of the layers forming the external electrode, and is a top surface facing the electrodes of the LED chip having positive and negative electrodes provided on the same surface side and bonded via bumps. It is a layer that has. (Insulating Substrate) The glass epoxy resin 111 used as an insulating substrate in the present invention is easily available and excellent in heat resistance as compared with other epoxy resins and has a large mechanical strength. Is preferably used in. (Cu layer 110) The Cu layer 110 is formed by electroless plating on the upper surface of a glass epoxy resin plate in which a mold is installed in the portion where the insulating portion 113 is formed. Here, since Cu has better thermal conductivity than other metals, it is preferably used as a metal forming an external electrode in the light emitting device of the present invention, and the Cu layer is formed thicker than other external electrodes. I don't mind. Further, the thickness of the mold in the portion where the insulating portion 113 is formed is larger than the thickness of the entire external electrode 112. (Ni layer 109) On the Cu layer 110, a Ni layer, which is one of the metals having good wettability for Cu, that is, the Ni layer 109 is formed by electroless plating. Ni layer 109
Has a lower thermal conductivity than the Au layer 108 formed thereon, and is therefore preferably formed with a smaller layer thickness as compared with other external electrodes. Thereby, the heat dissipation of the light emitting device can be improved. (Au Layer 108) On the Ni layer 109, a layer of Au which is one of the metals having good wettability with Ni, that is, the Au layer 108 is formed by electrolytic plating. Since Au is more expensive than other external electrodes, it increases the production cost of the entire light emitting device. Therefore, it is preferable to form the Au layer 108, which is thinner than the other external electrodes, by electrolytic plating that allows the film thickness to be easily controlled and plated. (Ag Layer 107) After a mold is placed at a position where a through hole is formed in the Ag layer 107, the Ag layer 107 is formed on the Au layer 108 by electroless plating. Ag is one of the metals having good wettability with respect to Au, and is also used as a reflective layer for reflecting the light emitted from the light emitting element and extracting the light to the emission observation surface. When Ag is used as the reflective layer, the high reflectance can be maintained even for light having a wavelength shorter than blue and the light extraction efficiency can be improved as compared with other external electrodes. It is preferably used as a metal. As other metal materials replacing Ag, Al, Pt, Pd, Rh, W, Ta, Re, Ti,
The reflective layer may be formed using V, Cr, Mn, Fe, Co, Ni or the like. In particular, when Al is used as the other metal material instead of Ag to form the reflective layer, Al is more effective than other metal materials not only for light in the visible light region but also for light having a wavelength shorter than blue. Since the high reflectance is maintained, the light extraction efficiency can be improved.

As described above, the Cu layer 110 and the Ni layer 10
9, after forming the Au layer 108 and the Ag layer 107,
By removing the mold installed in the portion where the insulating portion 113 is formed and the mold on the Au layer 108, a support unique to the present invention in which external electrodes are formed on a glass epoxy resin plate is completed. It The support unique to the present invention can be used not only for LED chips but also for various semiconductor chips such as laser diodes having a pair of positive and negative electrodes on the same surface side. [Bump 106] In the present invention, the bump used for die-bonding both the positive and negative electrodes of the LED chip and the external electrode is a bump having at least one kind of the same material as the positive and negative electrodes and the external electrode. For example, it is an Au bump generally used in ultrasonic bonding, a bump made of an alloy containing Au, or the like. The use of Au as the material for the bumps, which is the metal element contained in the electrode of the LED chip in the present invention and also the metal element contained in the surface of the external electrode exposed from the through hole of the reflection layer, has the same kind. It is preferable to join the materials containing the metal element, because the joining strength is increased. [Reflective Layer] (External Reflective Layer 201, Internal Reflective Layer 202) As the reflective layer in the present invention, an Ag layer having a through hole is used, and instead of the Ag layer, a member having elasticity in a cured state, The reflective layer is formed by using, for example, silicone resin. FIG. 2 shows a schematic cross-sectional view of a light emitting device in which a reflective layer including a member having elasticity in a cured state is formed instead of the Ag layer. As a member having elasticity in the cured state, when the electrodes of the LED chip and the external electrodes are joined via the bumps while also considering the number of bumps,
A member is selected whose elasticity is sufficiently larger than the elastic force of the contracted member and which does not cause a decrease in the bonding strength.

As shown in FIGS. 7 (j) and 8,
The reflective layer formed on the support before mounting the LED chip has at least two through holes with a shape (tapered shape) that widens in the opening direction from the bump formation location on the external electrode, and the LED chip can be stored during die bonding. It is a reflective layer having a uniform thickness. The overall outer shape of the reflective layer may be any shape such as a rectangular parallelepiped shape, a cylindrical shape, a polygonal prism shape, etc. as shown in FIG. There is 201, and the two are connected at two places. The external reflection layer 201 and the internal reflection layer 202 are simultaneously molded on the external electrode with the same material. The shape of the through-hole before mounting the LED chip may be a conical shape, a triangular pyramid shape, a polygonal pyramid shape such as a quadrangular pyramid shape, or the like.

In this embodiment, the hardness (JIS-A) 3 after curing is used as a member having elasticity in the cured state.
2. A colorless and transparent silicone resin is used, but is not limited to this. Since the silicone resin is soft and highly elastic in the cured state, after molding the external reflection layer 201 and the internal reflection layer 202 as shown in FIG.
When ultrasonic die bonding is performed by pressing the D chip from the substrate side, the external reflection layer 201 is slightly deformed and adheres to the side surface of the LED chip, and the internal reflection layer 202 is L.
It deforms to a state in which there is no space between the positive and negative electrodes of the ED chip and the external electrodes. Therefore, there is almost no air between the electrode surface or the side surface of the LED chip and the resin, the light emitted from the light emitting element is complicatedly refracted by the air, and the heat from the light emitting element generates air with a low thermal conductivity. Since the heat is not radiated through, the light extraction efficiency is improved and the heat dissipation effect is also enhanced. In particular, the internal reflection layer 202 formed above the insulating portion 113 from both the positive and negative electrodes of the LED chip to the external electrodes is more than the height of the external reflection layer 201 on the side to which the external wiring 701 is connected in advance before die bonding. It is formed to be 10 μm thick. Therefore, when the LED chip is die-bonded, the internal reflection layer 202 is pressed and compressed, but is soft and rich in elasticity. The gap is filled with the resin forming the internal reflection layer. Conventionally, after die-bonding an LED chip to a support, it was necessary to pour a molten resin from the lateral direction of the LED chip in order to fill a gap generated between the electrode chip electrode surface and the support. However, it is a very troublesome work to pour the resin completely without any gap, and the workability is deteriorated. However, in the present invention, it is possible to improve workability by die-bonding the LED chip after the reflective layer is pre-molded on the support with a resin. (Mold 601) The through hole in the reflective layer including a member having elasticity in the cured state becomes narrower toward the bump formation location on the Au layer 108, as shown in FIG. 7 (h) or FIG. It is molded by using a metal mold 601 having a shape (conical shape, triangular pyramid shape, quadrangular pyramid shape, or other inverse taper shape). It is preferable to mold the resin using a mold having such a shape because the mold is easily separated from the resin. Furthermore, since the resin molded by the mold having such a shape is easily deformed, the external reflection layer is closely attached to the side surface of the LED chip, and the internal reflection layer is L.
There is no space between the positive and negative electrodes of the ED chip and the external electrodes. (Release Agent) It is preferable that the mold has a release agent applied to the contact surface with the resin to form a film of the release agent. By doing so, when the Au layer 108 is filled with the molten resin and the resin is cured, and then the mold is removed, the resin does not adhere to the mold and the mold and the resin are easily separated from each other. Can be molded with good workability. In the present embodiment, a fluorine-based release agent is used as the release agent. Since this fluorine-based release agent does not easily stain the mold, it does not stain the surface of the resin to be molded and causes a decrease in translucency. It has oiliness and the like, and is most suitable for use when molding a reflection layer containing a resin using a mold having a complicated shape as in this embodiment. (Diffusing Agent) The resin used as the reflecting layer in the present embodiment contains a diffusing agent in order to improve the emission brightness of the light emitting device. The diffusing agent contained in the external reflection layer 201 and the internal reflection layer 202 reduces the scattering absorption of the light emitted from the light emitting element and is emitted to the light emission observation surface side, and the light directed to the side surface of the light reflection layer is reduced. By scattering a large amount of light, the emission brightness of the light emitting device is improved. As such a diffusing agent, inorganic members such as barium oxide, barium titanate, barium oxide, silicon oxide, titanium oxide and aluminum oxide, and organic members such as melamine resin, CTU guanamine resin and benzoguanamine resin are preferably used.

Similarly, various colorants may be added to have a filter effect of cutting out extraneous light and unnecessary wavelengths from the light emitting element. Furthermore, a fluorescent substance that emits fluorescence when excited by the wavelength of light emitted from the light emitting element can be included. Further, various fillers that relieve the internal stress of the resin can be contained. [Molding Member 301] In the present invention, the molding member 301 seals the LED chip 100 and the reflection layer 201, or fills a gap between the LED chip 100 and the inner wall of the external reflection layer 201, so that the light emitting element and the like are protected from the external environment. It is used to protect from external force, dust and water. By changing the shape of the mold member 301 in various ways, it is possible to select various directional characteristics of the light emitted from the light emitting element and the light received by the light receiving element. That is, the lens effect can be provided by forming the mold member 301 into a convex lens shape or a concave lens shape. for that reason,
Various shapes such as a dome shape, an elliptical shape when viewed from the side of the light emission observation surface, a cube, and a triangular prism can be selected as desired.

As a concrete mold member for an optical semiconductor element, an organic substance such as an epoxy resin, an acrylic resin, an imide resin, a silicon resin or the like having an excellent light resistance and a light transmitting property, or an inorganic substance such as glass can be selected. .. Further, aluminum oxide, barium oxide, barium titanate, silicon oxide or the like can be contained in the mold member for the purpose of diffusing light from the light emitting element. Similarly, various colorants may be added to have a filter effect of cutting out extraneous light and unnecessary wavelengths from the light emitting element. further,
A fluorescent substance that emits fluorescence when excited by the emission wavelength of the light emitting element is contained. Further, various fillers that relieve the internal stress of the mold resin may be contained. (Anisotropic Conductive Layer) In the present embodiment, the light emitting element is mounted so that the electrode formation surface side on which a pair of positive and negative electrodes is provided faces the external electrode on the support, and a continuous anisotropic It may be flip-chip mounted via a conductive layer. That is, the external reflection layer 201 and the internal reflection layer 202 described above
In place of the external reflection layer 201 and the internal reflection layer 202.
An anisotropic conductive layer may be formed at the same position as.

In the present invention, the anisotropic conductive layer is capable of efficiently reflecting the light from the light emitting element in an adhesive made of an organic or inorganic material having thermoplasticity or thermosetting property, and is electrically conductive. Conductive particles having properties are dispersed. Specific examples of the conductive particles include Ni particles, and particles having a metal coat made of Ni, Au, or the like on the surface of particles such as plastic and silica. In the present invention, the content of conductive particles is preferably 0.3 vol% or more and 1.2 vol% or less with respect to the adhesive, and such an anisotropic conductive layer is heated and pressed when mounting a light emitting element. Thus, high conductivity can be easily obtained between the film thickness directions of the layers. On the other hand, since the filling amount of the conductive particles is small in the plane direction of the layer, a short circuit between adjacent electrodes due to contact between the conductive particles does not occur, and high insulation can be maintained. More preferably, the number of particles per 1 mm ³ is 3 in the anisotropic conductive layer.
When the number is 500 or more and 5000 or less, the small light emitting element having a narrow pitch between the electrodes can be finely connected to the external electrodes on the base surface with high reliability. Furthermore, the anisotropic conductive layer can efficiently reflect and scatter light from the light emitting element.

In the present invention, the anisotropic conductive layer seals between the surface of the light emitting element and the surface of the external electrode which face each other, and directly covers a part of the side end surface of the light emitting element. . Thereby, a part of the light emitted from the light emitting element is taken into the anisotropic conductive layer, reflected and scattered by the conductive particles in the anisotropic conductive layer, and the light can be extracted in the front direction of the light emitting device. it can. Further, due to the presence of the anisotropic conductive layer between the electrode surface of the LED chip and the external electrode surface, there is no gap at all, the light extraction efficiency is improved, and the heat dissipation effect is also enhanced.

As a method of forming a light emitting device according to one embodiment of the present invention, a liquid anisotropic conductive layer material is formed in such a state that a bump formed in advance on the surface of an external electrode is covered appropriately and spreads to the size of a chip. Then, ultrasonic bonding is performed. With such a forming method, the electrode surface of the chip and the surface of the external electrode are bonded through both the adhesive contained in the anisotropic conductive layer and the bumps, so that the bonding strength is doubled. Furthermore, even when an external force is applied to the entire light-emitting device when performing the step of bending the electrode into a desired shape, the stress is relieved by the anisotropic conductive layer containing a highly elastic resin and the above-mentioned bonding is performed. Therefore, the light emitting device can have high reliability.

[0039]

EXAMPLES Examples of the present invention will be described in detail below. The present invention is not limited to the examples shown below. Example 1 As shown in FIG. 1, the support used in one example of the present invention was a glass epoxy resin 111 with C
The u, Ni, Au, and Ag layers are sequentially stacked to form the insulating portion 113.
The external electrodes are formed by being separated by. A used as a reflective layer in this example
A through hole is provided in the g layer 107, and the upper surface of the Au layer 108 is exposed by the through hole. In the light emitting device according to the present embodiment, the pair of positive and negative electrodes of the LED chip 100 are flip-chip mounted and bonded (bonded) to the Au layer 108 via the Au bumps in the through holes provided in the Ag layer. Become. Furthermore, the Ag layer 107 is connected to the external wiring 701.

The method of forming the external electrode 112 in this embodiment will be described step by step with reference to FIGS. 5 and 6. Further, a method of manufacturing the light emitting device as shown in FIG. 1 will be described. (Step 1) As shown in FIGS. 5A and 5B, the external electrode 11 is provided at a predetermined position on the upper surface of the glass epoxy resin plate.
After installing the mold 401 having a thickness of 2 or more,
A Cu layer 110 having a thickness of 18 to 70 μm is formed on a glass epoxy resin plate by immersing in a copper melt and electroless plating. Here, the upper surface of the glass epoxy resin plate is L
It has an area sufficiently larger than the upper surface of the ED chip substrate, and the thickness of the glass epoxy resin plate is arbitrary. The mold 401 used in this step is used as a mask for forming the insulating portion 113 that insulates and separates the external electrodes. (Step 2) After the Cu layer 110 is formed, the support is immersed in a nickel melt and electroless plating is performed to form a Ni layer 110 having a thickness of 4.0 μm as shown in FIG. Form on top. (Step 3) After the Ni layer 109 is formed, the support is immersed in a gold melt and the thickness is controlled by electrolytic plating to a thickness of 0.3-2. 0 μm A
The u layer 108 is formed on the Ni layer 109. (Step 4) After forming the Au layer 108 serving as a bonding layer, as shown in FIG. 6E, a mold 501 is set at a bump setting place on the Au layer 108, and a support is melted with a silver melt. Then, as shown in FIG. 5F, an Ag layer 107 having a thickness of 5.0 μm is formed on the Au layer 108 by electroless plating. Here, the mold 501 used in this step
Is used as a mask to form a through hole in the Ag layer 107. (Step 5) By removing the molds 401 and 501, as shown in FIG.
A support on which 2 is formed can be obtained. That is, the external electrode 112 is formed by sequentially stacking Cu, Ni, Au, and Ag layers on the glass epoxy resin 111 and separating them by the insulating portion 113. A through hole is provided in the Ag layer 107 used as the reflective layer in this embodiment, and the upper surface of the Au layer 108 is exposed by the through hole. (Step 6) Au bumps 106 are bonded to the upper surfaces of the Au layers 108 in the two through-holes formed by the above steps by a bump bonder. Here, a plurality of bumps may be bonded in each through hole. Increasing the number of bumps in this way is preferable because it increases the bonding strength between the positive and negative electrodes of the LED chip and the Au layer 108 of the external electrode. The height of the Au bump 106 is Ag layer 1
It is preferable that the thickness is sufficiently higher than the thickness of 07 and the amount of the Au bumps 106 is such that electrical conduction can be established between the positive and negative electrodes of the LED chip and the Au layer 108 of the external electrodes. When the bump amount is adjusted in this way, the LED chip electrode 1
Even when the size of 03 and 104 is larger than the inner diameter of the through hole and the electrode cannot enter the through hole, the electrodes 103 and 104 of the LED chip are in contact with the Au bump above the through hole and the Au bump is interposed therebetween. Since it is joined to the Au layer 108 of the external electrode, it is possible to ensure electrical conduction between the positive and negative electrodes of the LED chip and the Au layer 108 of the external electrode and prevent the production yield from decreasing. In this embodiment, the maximum diameter is about 80μ.
m, and Au bumps having a maximum height of about 40 μm were bonded.

By contacting the positive and negative electrode surfaces of the LED chip with the upper surface of the Au bump 106 and applying ultrasonic waves while applying pressure from the substrate side of the LED chip in the heat-retaining state,
Both the positive and negative electrodes of the LED chip and the Au layer 108 were opposed to each other and bonded via the Au bumps 106. The bonding strength through the Au bump was about 50 gf per bump. (Step 7) Finally, by cutting the support for each LED chip and connecting it to the external wiring 701, a plurality of light emitting devices as shown in FIG. 1 can be obtained at a time. The support may be cut so that a plurality of LED chips are die-bonded on the same support. The shape of the support after cutting may be any shape other than rectangular.

With the structure as in Example 1, Au used as the electrode material of the LED chip is also used as the material of the bump, and it is preferable to use the same metal because the bonding strength is increased. Further, the Ag layer 107 formed on the Au layer other than the bump installation location is
Since high reflectance is maintained even for light having a wavelength shorter than blue as compared with u and the like, when used as a reflective layer, the light extraction efficiency can be improved. [Embodiment 2] As shown in FIG. 2 or FIG. 9, the support used in another embodiment of the present invention is such that Cu, Ni and Au layers are laminated in this order on the glass epoxy resin 111.
It has an external electrode formed by being separated by the insulating portion 113. Further, in the light emitting device according to the present embodiment, the pair of positive and negative electrodes of the LED chip 100 are flip-chip mounted, and the Au layer 108 is provided via the Au bumps.
The external reflection layer 201 made of a resin having high elasticity in a cured state is provided around the LED chip 100, and the internal reflection layer 202 is LE.
It penetrates into the gap between the electrode surface of the D chip and the upper surface of the support. Further, the Au layer 108 is connected to the external wiring 701.

The method of forming the reflective layer in this embodiment will be described step by step with reference to FIGS. 7 and 8. Further, a method of manufacturing the light emitting device as shown in FIGS. 2 and 9 will be described. Here, FIGS. 2 and 7 are schematic cross-sectional views of the light emitting device or the support as shown in FIGS. 9 and 8 taken along the plane A, respectively.

In the same manner as in Example 1 from step 1 to step 3, Cu was sequentially added to the upper surface of the glass epoxy resin plate.
After forming the layer 110, the Ni layer 109, and the Au layer 108 as external electrodes, the mold 401 is removed, and instead, as shown in FIG.
(H) Alternatively, the mold 601 having the shape shown in FIG.
It is installed on the u layer 108. Here, the mold 601 having the shape shown in FIG. 7 (h) or FIG. 10 has a plurality of protrusions. Of these protrusions, the two protrusions (602) mask the portions on the Au layer 108 that connect the external wiring, and further two other protrusions (602).
3) masks a portion to be bump-bonded on the Au layer 108. As shown in FIG. 7 (h) or FIG. 10, by using a mold having a protruding portion (603) having a shape (quadrangular pyramid shape) which becomes narrower toward the bump formation location on the upper surface of the Au layer 108, After molding, the mold is easily separated from the resin. Further, the external reflection layer 201 and the internal reflection layer 202 are simultaneously molded by using the same material of resin, and the external reflection layer is slightly deformed to form an LED.
The internal reflection layer is closely attached to the side surface of the chip and is compressed by die bonding of the LED chip to fill the gap between the electrode surface of the LED chip and the support without any gap.

On the surface of the mold 601, a fluorine-based release agent is applied to the contact surface with the resin, and a release agent film of about 1 μm is provided. By doing so, the Au layer 10
8) After filling the top with molten resin and curing it, when removing the mold, the resin does not adhere to the mold and the resin easily separates from the mold, so it is necessary to mold a reflective layer made of resin with good workability. You can

With the die 601 placed on the Au layer 108, as shown in FIG. 7 (i), the molten silicon resin containing aluminum oxide used as a diffusing agent is skied to the height of the die 601. Fill by ging.

After the silicone resin is cured, the mold 601 is removed, and the external reflection layer 201 made of silicone resin is used.
Then, the internal reflection layer 202 is molded at the same time on the upper surface of the external electrode excluding the bump formation portion and above the insulating portion 113.
Here, the inner wall of the external reflection layer 201 has a tapered shape, and the minimum distance between the inner wall and the opposing inner wall is the LED chip 100.
Is a size that can be stored. Further, the outer wall of the internal reflection layer 202 has a reverse taper shape, and the minimum distance between the outer wall and the facing outer wall is substantially equal to the distance between the positive and negative electrodes of the LED chip. As a result, the external reflection layer is slightly deformed
The internal reflection layer is in close contact with the side surface of the ED chip, and exists between the positive and negative electrodes of the LED chip and the external electrode.

After molding the reflecting layer made of silicon resin, the Au bumps 106 and the Au layer 10 were formed in the same manner as in Example 1.
Bonding is carried out on the bump installation locations on 8 by a bump bonder so as to have the same amount and height as in the first embodiment.

Next, the positive and negative electrode surfaces of the LED chip are
The LED chip 100 is placed on the upper surface of the internal reflection layer 202 existing above the insulating portion 113 so as to be located directly above the u bumps 106 and face each other.

Using the ultrasonic bonding method as in Example 1, pressure is applied perpendicularly to the substrate surface of the LED chip 100 toward the support, and the surface of the Au bump 106 and both the positive and negative electrode surfaces of the LED chip are applied. The LED chip is die-bonded by flip-chip mounting in a state of contacting with. At this time, since the silicon resin existing on the insulating portion 113 is soft and rich in elasticity, it contracts due to the above-mentioned pressure, and LE
It often goes into the gap between the electrode surfaces of the D chip. In addition, the number of Au bumps in one through hole is set in advance before the die bonding so that the bonding force between the electrode of the LED chip and the external electrode is sufficiently larger than the elastic force of the silicon resin compressed by the die bonding. Adjust it. By doing so, the LED chip is not pushed back in the opposite direction to the support body by the elastic force of the silicon resin, and the strength of the bond between the electrode of the LED chip and the external electrode is always kept constant. Since the electrical continuity between the electrode and the external electrode is not interrupted, the manufacturing yield of the light emitting device does not decrease.

Finally, in the same manner as in Step 7 of Example 1, a light emitting device as shown in FIG. 2 or 9 was obtained.

The light emitting device having the structure as in Example 2 is
There is almost no gap between the reflective surface and the electrode surface and side surface of the LED chip. In addition, the LED chip side surface and the external reflection layer 2
When a gap is formed between the inner wall of 01 and the inner wall of 01, the light emitted from the LED chip is complicatedly refracted by the air present in the gap, resulting in a decrease in light extraction efficiency. Although the heat radiation effect is lowered by radiating heat from the light emitting element via the light emitting element, since no gap is formed in this embodiment, the light extraction efficiency of the light emitting device is improved and the heat radiation effect is also enhanced. [Embodiment 3] Similar to Embodiment 2, after the light emitting device as shown in FIG. 2 or 9 is obtained, the portion of the surface of the support that is connected to the external wiring 701 is masked and the external reflection layer is formed. They were sealed by squeezing or screen printing an epoxy resin on the substrate of 201 and LED chips. Finally, in the same manner as in Step 7 of Example 1, a light emitting device was obtained in which the upper surface of the external reflection layer 201 and the surface of the light emitting element substrate were molded with epoxy resin as shown in FIG.

With the structure of Example 3, it is possible to fill the small gap between the inner wall of the external reflection layer 201 and the side surface of the LED chip, and the external reflection layers 201 and L are formed.
It is possible to protect the ED chip from external force from the external environment, dust and water. Further, when a gap is formed between the side surface of the LED chip and the inner wall of the external reflection layer 201, the light emitted from the LED chip is complicatedly refracted by the air present in the gap, resulting in a decrease in light extraction efficiency. Further, although the light emitting device radiates heat through air having low thermal conductivity, the heat radiation effect is lowered, but in this embodiment, since no gap is formed, the light extraction efficiency of the light emitting device is improved,
The heat dissipation effect also increased. [Embodiment 4] Similar to Embodiment 1, after obtaining a light emitting device as shown in FIG. 1, a portion of the surface of the support which is connected to the external wiring 701 is masked and placed on the substrate of the LED chip. The LED chip was sealed by squeezing epoxy resin or screen printing. Finally, in the same manner as in Step 7 in Example 1, as shown in FIG.
A light emitting device in which the light emitting element was molded with epoxy resin was obtained.

With the structure of the fourth embodiment, the LED chip can be protected from external force from the external environment, dust and water. Example 5 After forming the light emitting device of Example 1,
A reflective layer made of resin was formed on the Ag layer in the same manner as in Example 2.

With the structure as in Example 5, the light extracted from the light emitting element was reflected by both the surface of the Ag layer and the reflective layer, so that the light extraction efficiency of the light emitting device could be improved. [Embodiment 6] As in Embodiment 1, the Au bumps 106 are
Bonding is performed by a bump bonder on the u layer 108 so that the amount and height are the same as those in the first embodiment. After that, a liquid anisotropic conductive layer material is supplied to the portion where the LED chip 100 is to be die-bonded so as to cover the bump with a thickness of about the height of the bump and to spread in an area substantially equal to the size of the LED chip. To do.

Next, the LED chip 100 is placed so that the positive and negative electrode surfaces of the LED chip face directly above the Au bumps 106 with the liquid anisotropic conductive layer material interposed therebetween.

Using the ultrasonic bonding method as in Example 1, pressure is applied perpendicularly to the substrate surface of the LED chip 100 so that the Au bumps 106 and the positive and negative electrode surfaces of the LED chip are connected to each other. In a state where they face each other, the LED chip is die-bonded by flip chip mounting.

Through the above steps, a light emitting device as shown in FIG. 11 was formed. According to the present embodiment, it is possible to obtain a bonding strength higher than that of the conventional example and establish electrical continuity between the LED chip 100 and the external electrode, and further, the mechanical strength of the entire light emitting device exceeds that of the conventional example. Further, since there is at least an anisotropic conductive layer between the electrode surface of the LED chip and the external electrode surface excluding the bump installation portion, and there is no gap at all, the light extraction efficiency of the light emitting device is improved and heat dissipation is improved. The effect also increased. [Embodiment 7] The Au bump 106 is
Bonding is performed by a bump bonder on the u layer 108 so that the amount and height are the same as those in the first embodiment. After that, a liquid epoxy resin is supplied to a portion where the LED chip 100 is to be die-bonded so as to cover the bump with a thickness of about the height of the bump and to spread in an area substantially equal to the size of the LED chip. In addition,
Here, an insulating adhesive or the like may be used instead of the epoxy resin.

Next, the LED chip 100 is placed so that the positive and negative electrode surfaces of the LED chip face each other directly above the Au bumps 106 with a liquid epoxy resin in between.

Using the ultrasonic bonding method as in Example 1, pressure is applied perpendicularly to the substrate surface of the LED chip 100 toward the support, and the surface of the Au bumps 106 and the positive and negative electrode surfaces of the LED chip 100. The LED chips are die-bonded by flip-chip mounting in a state where they are opposed to each other. At this time, L
Since the liquid epoxy resin existing between the positive and negative electrode surfaces of the ED chip and the surface of the Au bump 106 is vibrated by ultrasonic waves, the upper portion of the Au bump 106 bonded and fixed to the external electrode surface is covered with epoxy. It is exposed from inside the resin and contacts both the positive and negative electrodes of the LED chip. Therefore, the positive and negative electrodes of the LED chip and the Au bump 106 are
Bonded without interposing an epoxy resin.

Through the above steps, a light emitting device as shown in FIG. 11 was formed by using an epoxy resin instead of the anisotropic conductive layer 203. According to this embodiment, sufficient bonding strength can be obtained to establish electrical continuity between the LED chip 100 and the external electrode, and the mechanical strength of the entire light emitting device is higher than that of the conventional example. Further, since at least the electrode surface of the LED chip and the external electrode surface excluding the bump installation portion are filled with epoxy resin and there is no gap at all, the light extraction efficiency of the light emitting device is improved and the heat dissipation effect is also enhanced. . [Embodiment 8] The Au bump 106 is connected to the LED chip 100.
Bonding is carried out on both the positive and negative electrode surfaces by the bump bonder so as to have the same amount and height as in the sixth embodiment. After that, a liquid epoxy resin is supplied to the portion where the LED chip 100 is to be die-bonded so as to spread in a thickness about the height of the bump and in an area substantially equal to the size of the LED chip. Here, an insulating adhesive or the like may be used instead of the epoxy resin.

Next, A on both the positive and negative electrode surfaces of the LED chip
LE so that the u bumps 106 face directly above both the positive and negative electrodes of the external electrode via the liquid epoxy resin.
The D chip 100 is placed.

A state where the Au bump 106 and the external electrode surface are opposed to each other by applying pressure perpendicularly to the substrate surface of the LED chip 100 using the ultrasonic bonding method as in the first embodiment. Then, the LED chip is die-bonded by flip-chip mounting. At this time, the liquid epoxy resin existing between the external electrode and the surface of the Au bump 106 is
Since it vibrates violently due to ultrasonic waves, the lower part of the Au bump 106 bonded and fixed to the LED chip pushes away the liquid epoxy resin and makes contact with the external electrode surface. Therefore, the external electrode and the Au bump 106 are
Bonded without interposing an epoxy resin.

Through the above steps, the light emitting device as shown in FIG. 11 was formed by using the epoxy resin instead of the anisotropic conductive layer 203. According to this embodiment, sufficient bonding strength can be obtained to establish electrical continuity between the LED chip 100 and the external electrode, and the mechanical strength of the entire light emitting device is higher than that of the conventional example. Further, since at least the electrode surface of the LED chip and the external electrode surface excluding the bump installation portion are filled with epoxy resin and there is no gap at all, the light extraction efficiency of the light emitting device is improved and the heat dissipation effect is also enhanced. .

[0065]

[Effects of the Invention] By ultrasonically die-bonding each electrode of the light-emitting element and the external electrode through the bump having at least one kind of the same material, the portions containing the same kind of metal element are joined to each other. Can be kept high. Further, when a metal that maintains a high reflectance with respect to light having a wavelength shorter than blue is used as the material of the reflective layer, the light extraction efficiency of the light emitting device that emits light having a wavelength shorter than blue is improved.

Further, when a member which is soft and has a high elasticity in a cured state is molded and used as the reflection layer in a shape unique to the present invention, not only the light extraction efficiency is improved but also the heat dissipation effect is enhanced. In addition, after the reflective layer including a soft and highly elastic member in the cured state is previously molded on the support, LE
Workability is improved by die-bonding the D chip.

[0067]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a support showing a step of forming an external electrode according to the present invention.

FIG. 6 is a schematic cross-sectional view of a support showing a process of forming a reflective layer according to the present invention.

FIG. 7 is a schematic cross-sectional view of a support showing a process of forming a reflective layer according to the present invention.

FIG. 8 is a schematic perspective view of a support according to the present invention.

FIG. 9 is a schematic perspective view of a light emitting device according to the present invention.

FIG. 10 is a schematic perspective view of a mold according to an embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

[Explanation of symbols]

100 ... LED chip 101 ... Sapphire substrate 102 ... N-type nitride semiconductor 103 ... Negative electrode 104 ... Positive electrode 105 ... p-type nitride semiconductor 106 ... Bump 107 ... Ag layer 108 ... Au layer 109 ... Ni layer 110 ... Cu layer 112 ... External electrode 113 ... Insulation part 201 ... External reflection layer 202 ... Internal reflection layer 203 ... Anisotropic conductive layer 301: Mold member 401, 501, 601 ... Mold 602, 603 ... Mold projection 701 ... External wiring

[Procedure amendment]

[Submission date] September 6, 2002 (2002.9.6)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Light emitting device and method for manufacturing the same

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device using a nitride semiconductor light emitting element, and an object of the present invention is to provide a highly reliable light emitting device capable of emitting light with high luminance and high brightness. .

[0002]

2. Description of the Related Art In the case of bonding an LED chip to an external electrode of a support by flip-chip mounting, a new bonding technique using ultrasonic waves has recently appeared and is becoming mainstream. This ultrasonic bonding method is as follows.

First, Au bumps are formed on the conductor of the support placed on the stage.

Next, with the electrode surface of the LED chip having both positive and negative electrodes provided on the same surface side facing downward, the Au bumps are brought into contact with both the positive and negative electrode surfaces of the LED chip containing Au.

Finally, while the external electrodes, the positive and negative electrode surfaces of the LED chip, and the Au bumps are heated, pressure is applied so that the distance between the upper surface of the external electrodes and the LED chip electrode surface is narrowed, Ultrasonic vibration is applied to the electrodes, the positive and negative electrode surfaces of the LED chip, and the Au bumps. At this time, the heat and the frictional heat generated by the ultrasonic vibration melt the contact portion between the Au bump and the support and both the positive and negative electrode surfaces. Stuck to.

In this way, the external electrodes of the support and the positive and negative electrodes of the LED chip are joined via the Au bumps,
Electrical connection between the two is achieved.

Here, flip chip mounting refers to a method in which the electrode surface of a semiconductor chip having both positive and negative electrodes on the same surface side is the lower side and direct surface connection is made to the conductor of the support.

[0008]

However, when a light emitting device is formed using an LED chip that emits light having a short wavelength such as blue light and an Au-plated support, Au is used.
Has a low reflectance for light having a short wavelength, such as blue, and cannot improve the light extraction efficiency. When Ag or the like having high light reflectance is used as the plating material on the support, the Au formed on the Ag-plated portion of the support is used.
Joining the bump and the positive and negative electrodes containing Au of the LED chip is joining between different materials. Therefore, the joining method using ultrasonic waves causes a decrease in the joining strength and a decrease in productivity. It was

[0009]

SUMMARY OF THE INVENTION The present invention provides light emission including a light emitting element having a pair of positive and negative electrodes on the same surface side, and a support having external electrodes separately laminated on the surface of an insulating substrate. In the device, an upper surface of the external electrode is covered with a reflective layer having a through hole, and each electrode of the light emitting element is exposed from the through hole through a bump having at least one kind of material same as the external electrode. The light emitting device is characterized by facing the surface of the external electrode.

With the structure according to claim 1 of the present invention, the electrodes of the light emitting element and the external electrodes are ultrasonically die-bonded through the bumps having at least one kind of the same material, so that the same kind of metal is formed. Since the portions containing the elements are bonded to each other, the bonding strength can be kept high. Further, when a metal that maintains a high reflectance for light having a wavelength shorter than that of blue is used as the material of the reflective layer and the light emitting device emits light having a wavelength shorter than that of blue, the light extraction efficiency can be improved. It is possible.

The invention according to claim 2 is the light-emitting device according to claim 1, wherein the light-emitting element is sealed with a mold member.

With the structure according to the second aspect of the present invention, the light emitting element and the like can be protected from external force from the external environment, dust and water.

According to a third aspect of the present invention, a light emitting element having a pair of positive and negative electrodes on the same surface side, a support having external electrodes separately laminated on the surface of an insulating substrate, and a support on the support are provided. An external reflection layer having a through hole that is placed and capable of accommodating the light emitting element, wherein each electrode of the light emitting element has the through hole through a bump having at least one material that is the same as the external electrode. The light emitting device is characterized in that it has an internal reflection layer made of the same material as the external reflection layer, between the electrodes and between the external electrodes, the internal reflection layer facing the external electrode surface exposed from.

With the structure according to claim 3 of the present invention, when a soft and highly elastic resin such as a silicone resin containing a diffusing agent is molded into a unique shape for use in the present invention as the reflecting layer, Not only can the light extraction efficiency be improved, but also the heat dissipation effect can be improved.

According to a fourth aspect of the invention, there is provided the light emitting device according to the third aspect, wherein the inner wall of the outer reflection layer is tapered and the outer wall of the inner reflection layer is inversely tapered. is there.

With the structure according to claim 4 of the present invention, the outer reflection layer can be brought into close contact with the side surface of the LED chip by only slightly deforming the inner reflection layer.
It is possible to exist without any gap between the positive and negative electrodes of the chip and the external electrodes.

The invention according to claim 5 is the light-emitting device according to any one of claims 3 to 4, characterized in that the external reflection layer has a molding member.

With the structure according to the fifth aspect of the present invention, it is possible to protect the light emitting element and the like from external force from the external environment, dust and water.

According to a sixth aspect of the present invention, the outer reflection layer and / or the inner reflection layer contains a fluorescent substance that emits fluorescence when excited by the emission wavelength of the light emitting element. It is a light emitting device.

With the structure according to the sixth aspect of the present invention, it is possible to provide a light emitting device which emits fluorescence excited by the emission wavelength from the light emitting element.

According to a seventh aspect of the present invention, a light emitting element having a pair of positive and negative electrodes on the same surface side, a support having external electrodes separately laminated on the surface of an insulating substrate, and a support on the support are provided. In a method of manufacturing a light emitting device having an external reflection layer having a through hole that is placed and capable of accommodating the light emitting element, a through hole in which a part of each surface of the external electrode is exposed is provided on the support. A first step of forming the reflective layer having a resilient member in a cured state, a second step of forming bumps in the through-holes, and the electrodes of the light-emitting element being the bumps. And a third step of facing each other and pressing the light emitting element toward the support to electrically connect the light emitting element.

By the method according to claim 7 of the present invention, a member having elasticity in a cured state is molded into a shape unique to the present invention and used as a reflective layer, and the light extraction efficiency and heat dissipation are improved. A light emitting device with improved effect can be easily manufactured. That is, conventionally, it was a very troublesome work to pour a resin or the like between the LED chip and the support without leaving a gap after the LED chip was die-bonded onto the support, but by the method according to the present invention, Workability can be improved by die-bonding the LED chip after the layer is preformed on the support.

According to an eighth aspect of the present invention, the reflective layer comprises:
The method for manufacturing a light emitting device according to claim 7, wherein the mold is formed by a mold having a release agent applied inside.

By the method according to claim 8 of the present invention, after the member having elasticity in the cured state is cured, the member is prevented from adhering to the surface of the mold when the mold is removed. Since the mold surface and the member are easily separated, the reflective layer can be molded with good workability.

[0025]

As a result of various studies, the present inventor has a reflection layer having a through hole and an external electrode exposed from the through hole on the upper surface of the external electrode, and each electrode of the light emitting element is Provided is a light emitting device that does not reduce light extraction efficiency or bonding strength by connecting an external electrode exposed from a through hole via a bump having at least one kind of the same material contained in the external electrode. Made possible. That is,
As shown in FIG. 1, the support used in one embodiment of the present invention is composed of Cu, Ni, A on a glass epoxy resin 111.
The u and Ag layers are sequentially stacked, and have external electrodes formed by being separated by the insulating portion 113. Through holes are provided in the Ag layer 107 used as the reflection layer in this embodiment, and the Au layer 10 is formed by the through holes.
The upper surface of 8 is exposed. Then, in the light emitting device according to the present embodiment, the pair of positive and negative electrodes of the LED chip 100 is bonded (bonded) to the Au layer 108 via the Au bump 106 in the through hole provided in the Ag layer by flip chip mounting. It becomes. Furthermore, the Ag layer 107 is connected to the external wiring 701.

Further, as shown in FIG. 2, the support used in another embodiment of the present invention is such that Cu, Ni and Au layers are laminated in this order on the glass epoxy resin 111, and the insulating portion 113 is used. It has an external electrode formed by being separated. In the light emitting device according to the present embodiment, a pair of positive and negative electrodes of the LED chip 100 are flip-chip mounted to be bonded (joined) to the Au layer 108 via Au bumps, and the resin is highly elastic in a cured state. The external reflection layer 201 composed of the LED chip 1
00, the internal reflection layer 202 is inserted into the gap between the electrode surface of the LED chip and the upper surface of the support. Further, the Au layer 108 is connected to the external wiring 701.

Here, the negative electrode 10 of the LED chip 100 is used.
3 and the positive electrode 104 and the external electrode on the upper surface of the support are bonded by ultrasonic bonding.

Hereinafter, each structure of the embodiment of the present invention will be described in detail. [LED Chip 100] In the present embodiment, the LED chip 100 is used as the light emitting element in the present invention. Examples of the semiconductor light emitting device used in the present invention include those using various semiconductors such as ZnSe and GaN. When a fluorescent substance is used, a short wavelength that can efficiently excite the fluorescent substance capable of emitting nitride semiconductor _{(In X Al Y Ga 1-} X-Y N, 0
≦ X, 0 ≦ Y, X + Y ≦ 1) are preferable. Examples of the semiconductor structure include a homo structure having a MIS junction, a PIN junction, a pn junction, etc., a hetero structure, and a double hetero structure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal thereof. Further, the semiconductor active layer may be formed as a thin film in which a quantum effect is generated, and may have a single quantum well structure or a multiple quantum well structure.

When a nitride semiconductor is used, materials such as sapphire, spinel, SiC, Si and ZnO are preferably used for the semiconductor substrate. A sapphire substrate is preferably used in order to form a nitride semiconductor having good crystallinity with good mass productivity. MOCVD on this sapphire substrate
A nitride semiconductor can be formed by using a method or the like. A buffer layer of GaN, AlN, GaAlN or the like is formed on a sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.

As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer made of n-type gallium nitride on a buffer layer, and a first clad made of n-type aluminum gallium nitride. A layer, an active layer made of indium gallium nitride, a second cladding layer made of p-type aluminum nitride gallium, and a second contact layer made of a second contact layer made of p-type gallium nitride in this order. Can be mentioned.

The nitride semiconductor exhibits n-type conductivity in a state where it is not doped with impurities. When forming a desired n-type nitride semiconductor such as improving the luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C or the like as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, Zn, Mg, Be, and C which are p-type dopants are used.
Doping with a, Sr, Ba and the like. Nitride semiconductor is p
Since it is difficult to form a p-type by only doping with a type dopant, it is preferable to reduce the resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant.

When an insulating substrate such as sapphire is used as the substrate, the positive and negative electrodes are formed, and then the semiconductor wafer is cut into chips to obtain a nitride semiconductor chip having the positive and negative electrodes on the same side. Thus, a light emitting element can be formed. Here, by forming the positive and negative electrodes parallel to each other, it is possible to stably mount the support according to the present invention, and the current flowing between the electrodes becomes uniform, so that the light emission from the light emitting surface of the light emitting element becomes uniform. Therefore, it is preferable. [External Electrode 112] The external electrode 112 in the present invention is
It is formed separately on the upper surface of the insulating substrate. Here, the external electrode 112 in the present invention may be formed on the entire upper surface of the insulating substrate, but may be formed in various conductive patterns on a part of the upper surface of the insulating substrate. The metal forming the external electrode 112 is selected in consideration of good adhesion between metals, so-called wettability, and the like. When the electrode of the LED chip containing Au is bonded by ultrasonic die bonding via the Au bump, the bonding layer is an Au layer. Here, the bonding layer is one of the layers forming the external electrode, and is a top surface facing the electrodes of the LED chip having positive and negative electrodes provided on the same surface side and bonded via bumps. It is a layer that has. (Insulating Substrate) The glass epoxy resin 111 used as an insulating substrate in the present invention is easily available and excellent in heat resistance as compared with other epoxy resins and has a large mechanical strength. Is preferably used in. (Cu layer 110) The Cu layer 110 is formed by electroless plating on the upper surface of a glass epoxy resin plate in which a mold is installed in the portion where the insulating portion 113 is formed. Here, since Cu has better thermal conductivity than other metals, it is preferably used as a metal forming an external electrode in the light emitting device of the present invention, and the Cu layer is formed thicker than other external electrodes. I don't mind. Further, the thickness of the mold in the portion where the insulating portion 113 is formed is larger than the thickness of the entire external electrode 112. (Ni layer 109) On the Cu layer 110, a Ni layer, which is one of the metals having good wettability for Cu, that is, the Ni layer 109 is formed by electroless plating. Ni layer 109
Has a lower thermal conductivity than the Au layer 108 formed thereon, and is therefore preferably formed with a smaller layer thickness as compared with other external electrodes. Thereby, the heat dissipation of the light emitting device can be improved. (Au Layer 108) On the Ni layer 109, a layer of Au which is one of the metals having good wettability with Ni, that is, the Au layer 108 is formed by electrolytic plating. Since Au is more expensive than other external electrodes, it increases the production cost of the entire light emitting device. Therefore, it is preferable to form the Au layer 108, which is thinner than the other external electrodes, by electrolytic plating that allows the film thickness to be easily controlled and plated. (Ag Layer 107) After a mold is placed at a position where a through hole is formed in the Ag layer 107, the Ag layer 107 is formed on the Au layer 108 by electroless plating. Ag is one of the metals having good wettability with respect to Au, and is also used as a reflective layer for reflecting the light emitted from the light emitting element and extracting the light to the emission observation surface. When Ag is used as the reflective layer, the high reflectance can be maintained even for light having a wavelength shorter than blue and the light extraction efficiency can be improved as compared with other external electrodes. It is preferably used as a metal. As other metal materials replacing Ag, Al, Pt, Pd, Rh, W, Ta, Re, Ti,
The reflective layer may be formed using V, Cr, Mn, Fe, Co, Ni or the like. In particular, when Al is used as the other metal material instead of Ag to form the reflective layer, Al is more effective than other metal materials not only for light in the visible light region but also for light having a wavelength shorter than blue. Since the high reflectance is maintained, the light extraction efficiency can be improved.

As described above, the Cu layer 110 and the Ni layer 10
9, after forming the Au layer 108 and the Ag layer 107,
By removing the mold installed in the portion where the insulating portion 113 is formed and the mold on the Au layer 108, a support unique to the present invention in which external electrodes are formed on a glass epoxy resin plate is completed. It The support unique to the present invention can be used not only for LED chips but also for various semiconductor chips such as laser diodes having a pair of positive and negative electrodes on the same surface side. [Bump 106] In the present invention, the bump used for die-bonding both the positive and negative electrodes of the LED chip and the external electrode is a bump having at least one kind of the same material as the positive and negative electrodes and the external electrode. For example, it is an Au bump generally used in ultrasonic bonding, a bump made of an alloy containing Au, or the like. The use of Au as the material for the bumps, which is the metal element contained in the electrode of the LED chip in the present invention and also the metal element contained in the surface of the external electrode exposed from the through hole of the reflection layer, has the same kind. It is preferable to join the materials containing the metal element, because the joining strength is increased. [Reflective Layer] (External Reflective Layer 201, Internal Reflective Layer 202) As the reflective layer in the present invention, an Ag layer having a through hole is used, and instead of the Ag layer, a member having elasticity in a cured state, The reflective layer is formed by using, for example, silicone resin. FIG. 2 shows a schematic cross-sectional view of a light emitting device in which a reflective layer including a member having elasticity in a cured state is formed instead of the Ag layer. As a member having elasticity in the cured state, when the electrodes of the LED chip and the external electrodes are joined via the bumps while also considering the number of bumps,
A member is selected whose elasticity is sufficiently larger than the elastic force of the contracted member and which does not cause a decrease in the bonding strength.

As shown in FIG. 7 (j) and FIG.
The reflective layer formed on the support before mounting the LED chip has at least two through holes with a shape (tapered shape) that widens in the opening direction from the bump formation location on the external electrode, and the LED chip can be stored during die bonding. It is a reflective layer having a uniform thickness. The overall outer shape of the reflective layer may be any shape such as a rectangular parallelepiped shape, a cylindrical shape, a polygonal prism shape, etc. as shown in FIG. There is 201, and the two are connected at two places. The external reflection layer 201 and the internal reflection layer 202 are simultaneously molded on the external electrode with the same material. The shape of the through-hole before mounting the LED chip may be a conical shape, a triangular pyramid shape, a polygonal pyramid shape such as a quadrangular pyramid shape, or the like.

In this embodiment, the hardness (JIS-A) 3 after curing is used as the member having elasticity in the cured state.
2. A colorless and transparent silicone resin is used, but is not limited to this. Since the silicone resin is soft and highly elastic in the cured state, after molding the external reflection layer 201 and the internal reflection layer 202 as shown in FIG.
When ultrasonic die bonding is performed by pressing the D chip from the substrate side, the external reflection layer 201 is slightly deformed and adheres to the side surface of the LED chip, and the internal reflection layer 202 is L.
It deforms to a state in which there is no space between the positive and negative electrodes of the ED chip and the external electrodes. Therefore, there is almost no air between the electrode surface or the side surface of the LED chip and the resin, the light emitted from the light emitting element is complicatedly refracted by the air, and the heat from the light emitting element generates air with a low thermal conductivity. Since the heat is not radiated through, the light extraction efficiency is improved and the heat dissipation effect is also enhanced. In particular, the internal reflection layer 202 formed above the insulating portion 113 from both the positive and negative electrodes of the LED chip to the external electrodes is more than the height of the external reflection layer 201 on the side to which the external wiring 701 is connected in advance before die bonding. It is formed to be 10 μm thick. Therefore, when the LED chip is die-bonded, the internal reflection layer 202 is pressed and compressed, but is soft and rich in elasticity. The gap is filled with the resin forming the internal reflection layer. Conventionally, after die-bonding an LED chip to a support, it was necessary to pour a molten resin from the lateral direction of the LED chip in order to fill a gap generated between the electrode chip electrode surface and the support. However, it is a very troublesome work to pour the resin completely without any gap, and the workability is deteriorated. However, in the present invention, it is possible to improve workability by die-bonding the LED chip after the reflective layer is pre-molded on the support with a resin. (Mold 601) The through hole in the reflective layer including a member having elasticity in the cured state becomes narrower toward the bump formation location on the Au layer 108, as shown in FIG. 7 (h) or FIG. It is molded by using a metal mold 601 having a shape (conical shape, triangular pyramid shape, quadrangular pyramid shape, or other inverse taper shape). It is preferable to mold the resin using a mold having such a shape because the mold is easily separated from the resin. Furthermore, since the resin molded by the mold having such a shape is easily deformed, the external reflection layer is closely attached to the side surface of the LED chip, and the internal reflection layer is L.
There is no space between the positive and negative electrodes of the ED chip and the external electrodes. (Release Agent) It is preferable that the mold has a release agent applied to the contact surface with the resin to form a film of the release agent. By doing so, when the Au layer 108 is filled with the molten resin and the resin is cured, and then the mold is removed, the resin does not adhere to the mold and the mold and the resin are easily separated from each other. Can be molded with good workability. In the present embodiment, a fluorine-based release agent is used as the release agent. Since this fluorine-based release agent does not easily stain the mold, it does not stain the surface of the resin to be molded and causes a decrease in translucency. It has oiliness and the like, and is most suitable for use when molding a reflection layer containing a resin using a mold having a complicated shape as in this embodiment. (Diffusing Agent) The resin used as the reflecting layer in the present embodiment contains a diffusing agent in order to improve the emission brightness of the light emitting device. The diffusing agent contained in the external reflection layer 201 and the internal reflection layer 202 reduces the scattering absorption of the light emitted from the light emitting element and is emitted to the light emission observation surface side, and the light directed to the side surface of the light reflection layer is reduced. By scattering a large amount of light, the emission brightness of the light emitting device is improved. As such a diffusing agent, inorganic members such as barium oxide, barium titanate, barium oxide, silicon oxide, titanium oxide and aluminum oxide, and organic members such as melamine resin, CTU guanamine resin and benzoguanamine resin are preferably used.

Similarly, various colorants may be added to have a filter effect of cutting out extraneous light and unnecessary wavelengths from the light emitting element. Furthermore, a fluorescent substance that emits fluorescence when excited by the wavelength of light emitted from the light emitting element can be included. Further, various fillers that relieve the internal stress of the resin can be contained. [Molding Member 301] In the present invention, the molding member 301 seals the LED chip 100 and the reflection layer 201, or fills a gap between the LED chip 100 and the inner wall of the external reflection layer 201, so that the light emitting element and the like are protected from the external environment. It is used to protect from external force, dust and water. By changing the shape of the mold member 301 in various ways, it is possible to select various directional characteristics of the light emitted from the light emitting element and the light received by the light receiving element. That is, the lens effect can be provided by forming the mold member 301 into a convex lens shape or a concave lens shape. for that reason,
Various shapes such as a dome shape, an elliptical shape when viewed from the side of the light emission observation surface, a cube, and a triangular prism can be selected as desired.

As a concrete mold member for an optical semiconductor element, an organic substance such as an epoxy resin, an acrylic resin, an imide resin, a silicon resin or the like having an excellent light resistance and a light transmitting property, or an inorganic substance such as glass can be selected. . Further, aluminum oxide, barium oxide, barium titanate, silicon oxide or the like can be contained in the mold member for the purpose of diffusing light from the light emitting element. Similarly, various colorants may be added to have a filter effect of cutting out extraneous light and unnecessary wavelengths from the light emitting element. further,
A fluorescent substance that emits fluorescence when excited by the emission wavelength of the light emitting element is contained. Further, various fillers that relieve the internal stress of the mold resin may be contained. (Anisotropic Conductive Layer) In the present embodiment, the light emitting element is mounted so that the electrode formation surface side on which a pair of positive and negative electrodes is provided faces the external electrode on the support, and a continuous anisotropic It may be flip-chip mounted via a conductive layer. That is, the external reflection layer 201 and the internal reflection layer 202 described above
In place of the external reflection layer 201 and the internal reflection layer 202.
An anisotropic conductive layer may be formed at the same position as.

In the present invention, the anisotropic conductive layer is capable of efficiently reflecting the light from the light emitting element in an adhesive made of an organic or inorganic material having thermoplasticity or thermosetting property, and is electrically conductive. Conductive particles having properties are dispersed. Specific examples of the conductive particles include Ni particles, and particles having a metal coat made of Ni, Au, or the like on the surface of particles such as plastic and silica. In the present invention, the content of conductive particles is preferably 0.3 vol% or more and 1.2 vol% or less with respect to the adhesive, and such an anisotropic conductive layer is heated and pressed when mounting a light emitting element. Thus, high conductivity can be easily obtained between the film thickness directions of the layers. On the other hand, since the filling amount of the conductive particles is small in the plane direction of the layer, a short circuit between adjacent electrodes due to contact between the conductive particles does not occur, and high insulation can be maintained. More preferably, the number of particles per 1 mm ³ is 3 in the anisotropic conductive layer.
When the number is 500 or more and 5000 or less, the small light emitting element having a narrow pitch between the electrodes can be finely connected to the external electrodes on the base surface with high reliability. Furthermore, the anisotropic conductive layer can efficiently reflect and scatter light from the light emitting element.

In the present invention, the anisotropic conductive layer seals between the surface of the light emitting element and the surface of the external electrode which face each other, and directly covers a part of the side end surface of the light emitting element. . Thereby, a part of the light emitted from the light emitting element is taken into the anisotropic conductive layer, reflected and scattered by the conductive particles in the anisotropic conductive layer, and the light can be extracted in the front direction of the light emitting device. it can. Further, due to the presence of the anisotropic conductive layer between the electrode surface of the LED chip and the external electrode surface, there is no gap at all, the light extraction efficiency is improved, and the heat dissipation effect is also enhanced.

As a method of forming a light emitting device in one embodiment of the present invention, a liquid anisotropic conductive layer material is formed so as to appropriately cover the bumps previously formed on the surface of the external electrode and to spread to the size of the chip. Then, ultrasonic bonding is performed. With such a forming method, the electrode surface of the chip and the surface of the external electrode are bonded through both the adhesive contained in the anisotropic conductive layer and the bumps, so that the bonding strength is doubled. Furthermore, even when an external force is applied to the entire light-emitting device when performing the step of bending the electrode into a desired shape, the stress is relieved by the anisotropic conductive layer containing a highly elastic resin and the above-mentioned bonding is performed. Therefore, the light emitting device can have high reliability.

[0041]

EXAMPLES Examples of the present invention will be described in detail below. The present invention is not limited to the examples shown below. Example 1 As shown in FIG. 1, the support used in one example of the present invention was a glass epoxy resin 111 with C
The u, Ni, Au, and Ag layers are sequentially stacked to form the insulating portion 113.
The external electrodes are formed by being separated by. A used as a reflective layer in this example
A through hole is provided in the g layer 107, and the upper surface of the Au layer 108 is exposed by the through hole. In the light emitting device according to the present embodiment, the pair of positive and negative electrodes of the LED chip 100 are flip-chip mounted and bonded (bonded) to the Au layer 108 via the Au bumps in the through holes provided in the Ag layer. Become. Furthermore, the Ag layer 107 is connected to the external wiring 701.

A method of forming the external electrode 112 in this embodiment will be described step by step with reference to FIGS. 5 and 6. Further, a method of manufacturing the light emitting device as shown in FIG. 1 will be described. (Step 1) As shown in FIGS. 5A and 5B, the external electrode 11 is provided at a predetermined position on the upper surface of the glass epoxy resin plate.
After installing the mold 401 having a thickness of 2 or more,
A Cu layer 110 having a thickness of 18 to 70 μm is formed on a glass epoxy resin plate by immersing in a copper melt and electroless plating. Here, the upper surface of the glass epoxy resin plate is L
It has an area sufficiently larger than the upper surface of the ED chip substrate, and the thickness of the glass epoxy resin plate is arbitrary. The mold 401 used in this step is used as a mask for forming the insulating portion 113 that insulates and separates the external electrodes. (Step 2) After the Cu layer 110 is formed, the support is immersed in a nickel melt and electroless plating is performed to form a Ni layer 110 having a thickness of 4.0 μm as shown in FIG. Form on top. (Step 3) After the Ni layer 109 is formed, the support is immersed in a gold melt and the thickness is controlled by electrolytic plating to a thickness of 0.3-2. 0 μm A
The u layer 108 is formed on the Ni layer 109. (Step 4) After forming the Au layer 108 serving as a bonding layer, as shown in FIG. 6E, a mold 501 is set at a bump setting place on the Au layer 108, and a support is melted with a silver melt. Then, as shown in FIG. 5F, an Ag layer 107 having a thickness of 5.0 μm is formed on the Au layer 108 by electroless plating. Here, the mold 501 used in this step
Is used as a mask to form a through hole in the Ag layer 107. (Step 5) By removing the molds 401 and 501, as shown in FIG.
A support on which 2 is formed can be obtained. That is, the external electrode 112 is formed by sequentially stacking Cu, Ni, Au, and Ag layers on the glass epoxy resin 111 and separating them by the insulating portion 113. A through hole is provided in the Ag layer 107 used as the reflective layer in this embodiment, and the upper surface of the Au layer 108 is exposed by the through hole. (Step 6) Au bumps 106 are bonded to the upper surfaces of the Au layers 108 in the two through-holes formed by the above steps by a bump bonder. Here, a plurality of bumps may be bonded in each through hole. Increasing the number of bumps in this way is preferable because it increases the bonding strength between the positive and negative electrodes of the LED chip and the Au layer 108 of the external electrode. The height of the Au bump 106 is Ag layer 1
It is preferable that the thickness is sufficiently higher than the thickness of 07 and the amount of the Au bumps 106 is such that electrical conduction can be established between the positive and negative electrodes of the LED chip and the Au layer 108 of the external electrodes. When the bump amount is adjusted in this way, the LED chip electrode 1
Even when the size of 03 and 104 is larger than the inner diameter of the through hole and the electrode cannot enter the through hole, the electrodes 103 and 104 of the LED chip are in contact with the Au bump above the through hole and the Au bump is interposed therebetween. Since it is joined to the Au layer 108 of the external electrode, it is possible to ensure electrical conduction between the positive and negative electrodes of the LED chip and the Au layer 108 of the external electrode and prevent the production yield from decreasing. In this embodiment, the maximum diameter is about 80μ.
m, and Au bumps having a maximum height of about 40 μm were bonded.

Both the positive and negative electrode surfaces of the LED chip are brought into contact with the upper surface of the Au bump 106, and ultrasonic waves are applied while applying pressure from the substrate side of the LED chip in the heat retaining state.
Both the positive and negative electrodes of the LED chip and the Au layer 108 were opposed to each other and bonded via the Au bumps 106. The bonding strength through the Au bump was about 50 gf per bump. (Step 7) Finally, by cutting the support for each LED chip and connecting it to the external wiring 701, a plurality of light emitting devices as shown in FIG. 1 can be obtained at a time. The support may be cut so that a plurality of LED chips are die-bonded on the same support. The shape of the support after cutting may be any shape other than rectangular.

With the structure as in Example 1, Au which is used as the electrode material of the LED chip is also used as the material of the bump, and it is preferable to use the same metal because the bonding strength is increased. Further, the Ag layer 107 formed on the Au layer other than the bump installation location is
Since high reflectance is maintained even for light having a wavelength shorter than blue as compared with u and the like, when used as a reflective layer, the light extraction efficiency can be improved. [Embodiment 2] As shown in FIG. 2 or FIG. 9, the support used in another embodiment of the present invention is such that Cu, Ni and Au layers are laminated in this order on the glass epoxy resin 111.
It has an external electrode formed by being separated by the insulating portion 113. Further, in the light emitting device according to the present embodiment, the pair of positive and negative electrodes of the LED chip 100 are flip-chip mounted, and the Au layer 108 is provided via the Au bumps.
The external reflection layer 201 made of a resin having high elasticity in a cured state is provided around the LED chip 100, and the internal reflection layer 202 is LE.
It penetrates into the gap between the electrode surface of the D chip and the upper surface of the support. Further, the Au layer 108 is connected to the external wiring 701.

The method of forming the reflective layer in this embodiment will be described step by step with reference to FIGS. 7 and 8. Further, a method of manufacturing the light emitting device as shown in FIGS. 2 and 9 will be described. Here, FIGS. 2 and 7 are schematic cross-sectional views of the light emitting device or the support as shown in FIGS. 9 and 8 taken along the plane A, respectively.

In the same manner as in Example 1 from step 1 to step 3, Cu was sequentially added to the upper surface of the glass epoxy resin plate.
After forming the layer 110, the Ni layer 109, and the Au layer 108 as external electrodes, the mold 401 is removed, and instead, as shown in FIG.
(H) Alternatively, the mold 601 having the shape shown in FIG.
It is installed on the u layer 108. Here, the mold 601 having the shape shown in FIG. 7 (h) or FIG. 10 has a plurality of protrusions. Of these protrusions, the two protrusions (602) mask the portions on the Au layer 108 that connect the external wiring, and further two other protrusions (602).
3) masks a portion to be bump-bonded on the Au layer 108. As shown in FIG. 7 (h) or FIG. 10, by using a mold having a protruding portion (603) having a shape (quadrangular pyramid shape) which becomes narrower toward the bump formation location on the upper surface of the Au layer 108, After molding, the mold is easily separated from the resin. Further, the external reflection layer 201 and the internal reflection layer 202 are simultaneously molded by using the same material of resin, and the external reflection layer is slightly deformed to form an LED.
The internal reflection layer is closely attached to the side surface of the chip and is compressed by die bonding of the LED chip to fill the gap between the electrode surface of the LED chip and the support without any gap.

On the surface of the mold 601, a fluorine-based release agent is applied to the contact surface with the resin, and a release agent film of about 1 μm is provided. By doing so, the Au layer 10
8) After filling the top with molten resin and curing it, when removing the mold, the resin does not adhere to the mold and the resin easily separates from the mold, so it is necessary to mold a reflective layer made of resin with good workability. You can

With the mold 601 placed on the Au layer 108, as shown in FIG. 7I, the molten silicon resin containing aluminum oxide used as a diffusing agent is skied up to the height of the mold 601. Fill by ging.

After the silicone resin is cured, the mold 601 is removed, and the external reflection layer 201 made of silicone resin is used.
Then, the internal reflection layer 202 is molded at the same time on the upper surface of the external electrode excluding the bump formation portion and above the insulating portion 113.
Here, the inner wall of the external reflection layer 201 has a tapered shape, and the minimum distance between the inner wall and the opposing inner wall is the LED chip 100.
Is a size that can be stored. Further, the outer wall of the internal reflection layer 202 has a reverse taper shape, and the minimum distance between the outer wall and the facing outer wall is substantially equal to the distance between the positive and negative electrodes of the LED chip. As a result, the external reflection layer is slightly deformed
The internal reflection layer is in close contact with the side surface of the ED chip, and exists between the positive and negative electrodes of the LED chip and the external electrode.

After molding the reflecting layer made of silicon resin, the Au bump 106 and the Au layer 10 were formed in the same manner as in Example 1.
Bonding is carried out on the bump installation locations on 8 by a bump bonder so as to have the same amount and height as in the first embodiment.

Next, the positive and negative electrode surfaces of the LED chip are
The LED chip 100 is placed on the upper surface of the internal reflection layer 202 existing above the insulating portion 113 so as to be located directly above the u bumps 106 and face each other.

Using ultrasonic bonding as in Example 1, pressure is applied perpendicularly to the substrate surface of the LED chip 100 toward the support, and the surface of the Au bump 106 and the positive and negative electrode surfaces of the LED chip are both applied. The LED chip is die-bonded by flip-chip mounting in a state of contacting with. At this time, since the silicon resin existing on the insulating portion 113 is soft and rich in elasticity, it contracts due to the above-mentioned pressure, and LE
It often goes into the gap between the electrode surfaces of the D chip. In addition, the number of Au bumps in one through hole is set in advance before the die bonding so that the bonding force between the electrode of the LED chip and the external electrode is sufficiently larger than the elastic force of the silicon resin compressed by the die bonding. Adjust it. By doing so, the LED chip is not pushed back in the opposite direction to the support body by the elastic force of the silicon resin, and the strength of the bond between the electrode of the LED chip and the external electrode is always kept constant. Since the electrical continuity between the electrode and the external electrode is not interrupted, the manufacturing yield of the light emitting device does not decrease.

Finally, in the same manner as in Step 7 of Example 1, a light emitting device as shown in FIG. 2 or 9 was obtained.

The light emitting device having the structure as in Example 2 is
There is almost no gap between the reflective surface and the electrode surface and side surface of the LED chip. In addition, the LED chip side surface and the external reflection layer 2
When a gap is formed between the inner wall of 01 and the inner wall of 01, the light emitted from the LED chip is complicatedly refracted by the air present in the gap, resulting in a decrease in light extraction efficiency. Although the heat radiation effect is lowered by radiating heat from the light emitting element via the light emitting element, since no gap is formed in this embodiment, the light extraction efficiency of the light emitting device is improved and the heat radiation effect is also enhanced. [Embodiment 3] Similar to Embodiment 2, after the light emitting device as shown in FIG. 2 or 9 is obtained, the portion of the surface of the support that is connected to the external wiring 701 is masked and the external reflection layer is formed. They were sealed by squeezing or screen printing an epoxy resin on the substrate of 201 and LED chips. Finally, in the same manner as in Step 7 of Example 1, a light emitting device was obtained in which the upper surface of the external reflection layer 201 and the surface of the light emitting element substrate were molded with epoxy resin as shown in FIG.

With the structure as in Example 3, it is possible to fill a small gap between the inner wall of the external reflection layer 201 and the side surface of the LED chip, and the external reflection layers 201 and L are formed.
It is possible to protect the ED chip from external force from the external environment, dust and water. Further, when a gap is formed between the side surface of the LED chip and the inner wall of the external reflection layer 201, the light emitted from the LED chip is complicatedly refracted by the air present in the gap, resulting in a decrease in light extraction efficiency. Further, although the light emitting device radiates heat through air having low thermal conductivity, the heat radiation effect is lowered, but in this embodiment, since no gap is formed, the light extraction efficiency of the light emitting device is improved,
The heat dissipation effect also increased. [Embodiment 4] Similar to Embodiment 1, after obtaining a light emitting device as shown in FIG. 1, a portion of the surface of the support which is connected to the external wiring 701 is masked and placed on the substrate of the LED chip. The LED chip was sealed by squeezing epoxy resin or screen printing. Finally, in the same manner as in Step 7 in Example 1, as shown in FIG.
A light emitting device in which the light emitting element was molded with epoxy resin was obtained.

With the structure of the fourth embodiment, the LED chip can be protected from external force from the external environment, dust and water. Example 5 After forming the light emitting device of Example 1,
A reflective layer made of resin was formed on the Ag layer in the same manner as in Example 2.

With the structure of Example 5, the light extracted from the light emitting element was reflected by both the surface of the Ag layer and the reflective layer, so that the light extraction efficiency of the light emitting device could be improved. [Embodiment 6] As in Embodiment 1, the Au bumps 106 are
Bonding is performed by a bump bonder on the u layer 108 so that the amount and height are the same as those in the first embodiment. After that, a liquid anisotropic conductive layer material is supplied to the portion where the LED chip 100 is to be die-bonded so as to cover the bump with a thickness of about the height of the bump and to spread in an area substantially equal to the size of the LED chip. To do.

Next, the LED chip 100 is placed so that the positive and negative electrode surfaces of the LED chip face each other directly above the Au bumps 106 with the liquid anisotropic conductive layer material interposed therebetween.

Using the ultrasonic bonding method as in Example 1, pressure is applied perpendicularly to the substrate surface of the LED chip 100 so that the Au bumps 106 and the positive and negative electrode surfaces of the LED chip are connected to each other. In a state where they face each other, the LED chip is die-bonded by flip chip mounting.

Through the above steps, a light emitting device as shown in FIG. 11 was formed. According to the present embodiment, it is possible to obtain a bonding strength higher than that of the conventional example and establish electrical continuity between the LED chip 100 and the external electrode, and further, the mechanical strength of the entire light emitting device exceeds that of the conventional example. Further, since there is at least an anisotropic conductive layer between the electrode surface of the LED chip and the external electrode surface excluding the bump installation portion, and there is no gap at all, the light extraction efficiency of the light emitting device is improved and heat dissipation is improved. The effect also increased. [Embodiment 7] The Au bump 106 is
Bonding is performed by a bump bonder on the u layer 108 so that the amount and height are the same as those in the first embodiment. After that, a liquid epoxy resin is supplied to a portion where the LED chip 100 is to be die-bonded so as to cover the bump with a thickness of about the height of the bump and to spread in an area substantially equal to the size of the LED chip. In addition,
Here, an insulating adhesive or the like may be used instead of the epoxy resin.

Next, the LED chip 100 is placed so that the positive and negative electrode surfaces of the LED chip face each other directly above the Au bumps 106 with the liquid epoxy resin therebetween.

Using the ultrasonic bonding method as in Example 1, pressure is applied vertically to the substrate with respect to the substrate surface of the LED chip 100, and the surface of the Au bump 106 and both the positive and negative electrode surfaces of the LED chip are applied. The LED chips are die-bonded by flip-chip mounting in a state where they are opposed to each other. At this time, L
Since the liquid epoxy resin existing between the positive and negative electrode surfaces of the ED chip and the surface of the Au bump 106 is vibrated by ultrasonic waves, the upper portion of the Au bump 106 bonded and fixed to the external electrode surface is covered with epoxy. It is exposed from inside the resin and contacts both the positive and negative electrodes of the LED chip. Therefore, the positive and negative electrodes of the LED chip and the Au bump 106 are
Bonded without interposing an epoxy resin.

Through the above steps, the light emitting device as shown in FIG. 11 was formed by using the epoxy resin instead of the anisotropic conductive layer 203. According to this embodiment, sufficient bonding strength can be obtained to establish electrical continuity between the LED chip 100 and the external electrode, and the mechanical strength of the entire light emitting device is higher than that of the conventional example. Further, since at least the electrode surface of the LED chip and the external electrode surface excluding the bump installation portion are filled with epoxy resin and there is no gap at all, the light extraction efficiency of the light emitting device is improved and the heat dissipation effect is also enhanced. . [Embodiment 8] The Au bump 106 is connected to the LED chip 100.
Bonding is carried out on both the positive and negative electrode surfaces by the bump bonder so as to have the same amount and height as in the sixth embodiment. After that, a liquid epoxy resin is supplied to the portion where the LED chip 100 is to be die-bonded so as to spread in a thickness about the height of the bump and in an area substantially equal to the size of the LED chip. Here, an insulating adhesive or the like may be used instead of the epoxy resin.

Next, A on both positive and negative electrode surfaces of the LED chip
LE so that the u bumps 106 face directly above both the positive and negative electrodes of the external electrode via the liquid epoxy resin.
The D chip 100 is placed.

A state where the Au bump 106 and the external electrode surface are opposed to each other by applying pressure perpendicularly to the substrate surface of the LED chip 100 using the ultrasonic bonding method as in the first embodiment. Then, the LED chip is die-bonded by flip-chip mounting. At this time, the liquid epoxy resin existing between the external electrode and the surface of the Au bump 106 is
Since it vibrates violently due to ultrasonic waves, the lower part of the Au bump 106 bonded and fixed to the LED chip pushes away the liquid epoxy resin and makes contact with the external electrode surface. Therefore, the external electrode and the Au bump 106 are
Bonded without interposing an epoxy resin.

Through the above steps, the light emitting device as shown in FIG. 11 was formed by using the epoxy resin instead of the anisotropic conductive layer 203. According to this embodiment, sufficient bonding strength can be obtained to establish electrical continuity between the LED chip 100 and the external electrode, and the mechanical strength of the entire light emitting device is higher than that of the conventional example. Further, since at least the electrode surface of the LED chip and the external electrode surface excluding the bump installation portion are filled with epoxy resin and there is no gap at all, the light extraction efficiency of the light emitting device is improved and the heat dissipation effect is also enhanced. .

[0067]

[Effects of the Invention] By ultrasonically die-bonding each electrode of the light-emitting element and the external electrode through the bump having at least one kind of the same material, the portions containing the same kind of metal element are joined to each other. Can be kept high. Further, when a metal that maintains a high reflectance with respect to light having a wavelength shorter than blue is used as the material of the reflective layer, the light extraction efficiency of the light emitting device that emits light having a wavelength shorter than blue is improved.

Further, when a member which is soft and has a high elasticity in a cured state is molded into a shape unique to the present invention and used as the reflective layer, not only the light extraction efficiency is improved but also the heat dissipation effect is enhanced. In addition, after the reflective layer including a soft and highly elastic member in the cured state is previously molded on the support, LE
Workability is improved by die-bonding the D chip.

[0069]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a support showing a step of forming an external electrode according to the present invention.

FIG. 6 is a schematic cross-sectional view of a support showing a process of forming a reflective layer according to the present invention.

FIG. 7 is a schematic cross-sectional view of a support showing a process of forming a reflective layer according to the present invention.

FIG. 8 is a schematic perspective view of a support according to the present invention.

FIG. 9 is a schematic perspective view of a light emitting device according to the present invention.

FIG. 10 is a schematic perspective view of a mold according to an embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

[Explanation of symbols] 100 ... LED chip 101 ... Sapphire substrate 102 ... N-type nitride semiconductor 103 ... Negative electrode 104 ... Positive electrode 105 ... p-type nitride semiconductor 106 ... Bump 107 ... Ag layer 108 ... Au layer 109 ... Ni layer 110 ... Cu layer 112 ... External electrode 113 ... Insulation part 201 ... External reflection layer 202 ... Internal reflection layer 203 ... Anisotropic conductive layer 301: Mold member 401, 501, 601 ... Mold 602, 603 ... Mold projection 701 ... External wiring

Claims (7)

[Claims] 1. A light emitting device comprising: a light emitting element having a pair of positive and negative electrodes on the same surface side; and a support having an external electrode that is separately laminated on a surface of an insulating substrate, wherein an upper surface of the external electrode. Is covered with a reflective layer having a through hole, and each electrode of the light emitting element faces the external electrode surface exposed from the through hole via a bump having at least one material that is the same as the external electrode. A light-emitting device characterized by the above. 2. The light emitting device according to claim 1, wherein the light emitting element is sealed with a mold member. 3. A light emitting device having a pair of positive and negative electrodes on the same surface side, a support having external electrodes laminated separately on the surface of an insulating substrate, and the light emitting device mounted on the support and having the light emitting device mounted thereon. An external reflection layer having a storable through hole, wherein each electrode of the light emitting element has an external electrode surface exposed from the through hole via a bump having at least one material that is the same as the external electrode. A light emitting device having an internal reflection layer made of the same material as the external reflection layer, between the electrodes and between the external electrodes. 4. The light emitting device according to claim 3, wherein an inner wall of the outer reflective layer has a tapered shape, and an outer wall of the inner reflective layer has an inverse tapered shape. 5. The light emitting device according to claim 3, wherein a mold member is provided inside the external reflection layer. 6. A light emitting device having a pair of positive and negative electrodes on the same surface side, a support having external electrodes separately laminated on the surface of an insulating substrate, and the light emitting device mounted on the support In a manufacturing method of a light emitting device having an external reflection layer having a storable through hole, a reflective layer having a through hole in which a part of each surface of the external electrode is exposed is cured on the support. In the first step of forming a member having elasticity, a second step of forming a bump in each of the through holes, and each electrode of the light emitting element is opposed to the bump to form the light emitting element. And a third step of pressing in the direction of the support and electrically connecting the support, the method for manufacturing a light-emitting device. 7. The method of manufacturing a light emitting device according to claim 6, wherein the reflective layer is formed by a mold having a release agent applied inside.