JP2003273408A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable color conversion type light emitting device which has high productivity and a superior optical characteristic, and also to provide a method of manufacturing the same. <P>SOLUTION: The light emitting device comprises a light emitting element having a semiconductor layer which is formed on a substrate, a fluorescent material which absorbs part of light emitted from the light emitting element and can emit light of longer wavelengths than those of the light emitted from the light emitting element, and a translucent molding member which includes the fluorescent material and covers the surface of the light emitting element. There is at least one bump formed on an electrode of the light emitting element, with the top face of the bump nearly flush with the top face of the translucent molding member. <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 that can be used for a liquid crystal backlight, an illumination light source, various indicators, traffic lights, etc., and relates to a semiconductor light emitting element and a fluorescent substance capable of emitting light having a wavelength longer than that of the semiconductor light emitting element. And a method of forming the same.

[0002]

2. Description of the Related Art Today, semiconductors capable of emitting blue light with high brightness
Nitride semiconductor (In _xGa_yAl
_1-xyL using N, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1)
ED chips have been developed. Light emission using nitride semiconductors
The device uses other materials such as GaAs and AlInGaP
Compared with the light emitting element that emits red to yellow green, the output is
Features such as high temperature and little color shift due to temperature
However, to date, it has a wavelength above green.
There is a tendency that it is difficult to obtain high output in the long wavelength region.
It On the other hand, emitted from the LED chip on this LED chip
Absorbs at least part of the emitted blue light and emits yellow light
YAG: Ce phosphor, which is a possible fluorescent substance, is arranged.
Opens a light emitting diode that can emit white light.
Was issued. (International publication number WO98 / 5078)

In this light emitting diode, for example, an LED chip is arranged at the bottom of the mount lead in the cup,
The ED chip and the mount lead and the inner lead are electrically connected by a gold wire or the like. After connection, the cup is filled with a translucent mold resin containing a fluorescent substance that absorbs blue light from the LED chip and emits yellow light having a complementary color relationship. Finally, a convex lens is formed at the tip of both leads with a transparent resin or the like. In this way, the LED
An LED lamp that emits white light, which is a color mixture of light of a chip and a fluorescent substance, through a convex lens can be obtained.

In the above LED lamp, a light-transmissive mold resin containing a fluorescent substance is provided around the chip in advance, and then a convex lens member is formed of the light-transmissive resin or the like. As a result, the light from the chip becomes a desired color-mixed light when it passes through the translucent mold resin containing the fluorescent substance filled in the cup. Therefore, the color-converted light can be extracted favorably in the front direction. Further, by adjusting the shape of the cup, it is possible to suppress light scattering and improve the light emission output, and it is possible to easily obtain desired light emission characteristics.

[0005]

However, in such an LED lamp, it has been difficult to produce the LED lamp in a high yield with conspicuous emission unevenness and chromaticity variation as the size of the LED lamp becomes smaller.

Therefore, an object of the present invention is to provide a chip type long wavelength conversion type light emitting device having good productivity and excellent optical characteristics and a method for forming the same.

[0007]

That is, a light emitting device according to the present invention includes a light emitting element having a semiconductor layer on a substrate, and light having a wavelength longer than that of a part of light emitted from the light emitting element. A light-emitting device having a fluorescent substance capable of emitting light and a translucent mold member having the fluorescent substance and surrounding the surface of the light-emitting element, wherein at least one electrode is provided on the electrode of the light-emitting element.
It has two bumps, and the upper surface of the bump is substantially flush with the upper surface of the translucent mold member. As a result, it is possible to obtain a light emitting device which is highly reliable and can uniformly emit a desired color mixture light.

The thickness of the bump is 5 μm to 150 μm.
μm. As a result, a light emitting device capable of emitting light with high output is obtained.

Further, the upper surface of the light emitting device, which is composed of the upper surface of the bump and the upper surface of the translucent mold member, is substantially parallel to the bottom surface on the substrate side. As a result, a light emitting device having good directional characteristics can be obtained.

The fluorescent material is a Ce-activated yttrium-aluminum-garnet-based fluorescent material, Eu.
And / or nitrogen-containing been activated with Cr _CaO-Al 2 O
It is one type selected from _3- SiO ₂ . As a result, it is possible to obtain a simple and highly reliable light emitting device capable of emitting mixed light with high brightness.

Further, the invention is characterized in that it has a continuous reflection film on at least the substrate side of the light emitting element. This makes it possible to obtain a light emitting device having good light emitting efficiency and less uneven brightness.

In the method for forming a light emitting device according to the present invention, a light emitting element having a semiconductor layer on a substrate and a part of light from the light emitting element can be absorbed to emit light having a longer wavelength. A method for forming a light emitting device having a fluorescent substance and a translucent mold member having the fluorescent substance and surrounding the surface of the light emitting device, wherein bumps are formed on electrodes of the light emitting device in a wafer state. And a second step of covering the semiconductor layer side of the light emitting element with the material to be the translucent mold member so as to cover the bumps, and curing the material to be the translucent mold member. After that, there is a third step of exposing the upper surface of the bump from the semiconductor layer side in parallel with the bottom surface of the wafer by polishing, and a fourth step of cutting the wafer by dicing and scribing. Accordingly, the light emitting device can be formed with high productivity.

In the third step, the bumps are polished so that the thickness of each bump is 5 μm to 150 μm. As a result, it is possible to satisfactorily polish the fluorescent material in the mold member formed in the second step without breaking it, and to obtain a light emitting device which is highly reliable and can emit light uniformly.

Further, after the fourth step, a continuous light-transmissive mold member is formed on at least the substrate side of the light emitting element. The light emitting device thus obtained can have a light-transmissive mold member containing a fluorescent material on the entire outer periphery except for the bump upper surface that is electrically joined to the external electrode, and is highly reliable and has high color purity. Is obtained.

Further, after the fourth step, a continuous reflection film is formed on at least the substrate side of the light emitting element. Thereby, the light emitted from the substrate side of the light emitting element can be guided to the semiconductor layer side, and a light emitting device with less color unevenness and high light emission output can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of various experiments, the inventor of the present invention provided a light-transmissive mold member containing a fluorescent substance, which is a color conversion member, before electrically connecting the elements, so that the subsequent mounting process was performed. It has been found that a color conversion type light emitting device which can be simplified and has high reliability is obtained, and the present invention has been completed.

Conventionally, in the case of forming a wavelength conversion type LED lamp, it was necessary to previously provide a mold member containing a fluorescent substance in addition to the convex lens member for each element divided into elements. Specifically, the following process is required.

Each chip-shaped element is placed at the bottom of the mount lead inside the cup, and each electrode of the element is electrically connected to the lead electrode by a wire or the like. First, the chip-shaped element is placed in the cup so as to cover the element and the wire. A resin containing a fluorescent substance is dropped and injected by a dispenser or the like, and heat-cured to form a color conversion member. In this way, the first mold member is formed.

Thereafter, the resin, which is the material of the convex lens member, is poured into the casting case, and the leading end portion of the lead on which the color conversion member is formed is dipped and arranged. By placing this in an oven and curing it by heating, a convex lens member, which is a second mold member, is formed, and the wavelength-convertable L
An ED lamp is formed.

In order to form one light emitting device as described above, a step of filling each element with a resin and curing the same is required twice, and the waiting time for the resin effect is relatively long, which results in further production. The improvement of the sex is desired.

Further, as the light emitting device becomes smaller, the amount of the first mold member inevitably becomes smaller, and it is difficult to arrange the amount of the fluorescent substance necessary for obtaining the desired mixed color light with high accuracy for each element. It was extremely difficult, and the chromaticity variation occurred in each light emitting device, and the yield was poor.

Further, the light emitting device has a wire or the like in the color conversion member in order to provide the color conversion member after electrically connecting the light emitting element with the semiconductor layer as the upper surface. It is considered that such an electrical connection member adversely affects the arrangement of the fluorescent substance, reduces the light extraction efficiency of the fluorescent substance and the light emitting element, and causes color unevenness and output reduction.

Therefore, in the present invention, in order to solve the above problems, a color conversion member is provided in the light emitting element itself. Specifically, the electrode portion of the light emitting element is raised in a wafer state before being divided into individual light emitting elements, and a color conversion member is provided around the light emitting elements. With such a configuration, it is possible to form a color conversion type light emitting device having sufficiently high reliability and excellent optical characteristics with high productivity.

Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a light emitting diode according to an embodiment of the present invention. At least an n-type nitride semiconductor layer 2, an active layer (not shown), and a p-type nitride semiconductor layer 3 are sequentially stacked on an insulating substrate 1, and the p-type nitride semiconductor layer 3 is formed on almost the entire surface. The formed transparent first positive electrode 4, the second positive electrode 5 for bonding formed on a part of the first positive electrode 4, and exposed from the p-type nitride semiconductor layer 3 side by etching or the like. A light emitting element having a negative electrode 6 on the n-type nitride semiconductor layer 2 and having an insulating protective film 7 formed except for the bonding surface of each electrode is used. Bumps 8 are provided on the bonding surfaces of the respective electrodes of such a light emitting element, and the upper surfaces of these bumps are exposed so that the light-transmitting mold member 9 containing a fluorescent substance is provided on the upper surface and side surface of the light emitting element on the semiconductor layer side. It is provided. Hereinafter, each configuration of the present invention will be described in detail.

(Light Emitting Element) In the present invention, it is efficient that the light from the light emitting element has a shorter wavelength than the light emitted from the fluorescent substance. Therefore, as a semiconductor element capable of emitting visible light with high emission brightness with high efficiency, a nitride semiconductor (I
_{n x Ga y Al 1-x} -y N, 0 ≦ x ≦ 1,0 ≦ y ≦
Preferable examples are those using 1) as the active layer. A light emitting device using a nitride semiconductor can be formed on a sapphire substrate, a spinel (MgAi ₂ O ₄ ) substrate, SiC, a GaN single crystal or the like, but a sapphire substrate is required to satisfy mass productivity and crystallinity. It is preferable to use. Therefore, in the present invention, the light emitting element in which the n-type and p-type nitride semiconductor layers are formed on the sapphire substrate which is an insulating substrate and which has both electrodes on the semiconductor layer side is used.

More specifically, the light emitting device comprises an n-type nitride semiconductor layer 2 composed of one or more layers, an active layer (not shown), and one or more layers on a sapphire substrate 1. The p-type nitride semiconductor layer 3 is laminated, and positive and negative electrodes are formed as follows. That is, the positive electrode is composed of the first positive electrode 4 formed on almost the entire surface of the p-type nitride semiconductor layer and the second positive electrode 5 for bonding formed on a part of the first positive electrode. The negative electrode 6 is formed on the surface of the n-type nitride semiconductor layer exposed by removing a part of the p-type nitride semiconductor layer by dry etching or the like.

In the present invention, the n-type nitride semiconductor layer 2 and the p-type nitride semiconductor layer 3 are not particularly limited, and any layer structure may be used.

When the white light is emitted in the light emitting device of the present invention, the main light emission peak of the light emitting element is 400 nm or more 53 in consideration of the complementary color relation with the fluorescent substance and the deterioration of the resin.
It is preferably 0 nm or less, and more preferably 420 nm or more and 490 nm or less. In order to improve the efficiency of each of the light emitting device and the fluorescent substance, 450 nm or more and 470 nm or more
It is more preferable to use a light emitting device having a main emission peak below.

On the other hand, in the light-emitting device of the present invention, when the light-emitting element has a light-transmissive mold member containing a fluorescent substance, a resin or glass relatively resistant to ultraviolet rays is used.
It is also possible to obtain a light emitting device capable of emitting white light by using a light emitting element capable of emitting ultraviolet light having a short emission wavelength near 00 nm as a main emission peak. Due to such short wavelength light, red,
Phosphors that can fluoresce in blue and green, such as Y ₂ O ₂ S: Eu as a red phosphor and Sr ₅ (PO as a blue phosphor)
₄ ) ₃ Cl: Eu, and as a green phosphor (SrEu)
White light can be obtained by including O.Al ₂ O ₃ in the ultraviolet resistant resin or the like and applying it as a color conversion layer on the surface of a light emitting device emitting short wavelength light.

In one embodiment of the present invention, a light-transmissive mold member, which is a color conversion layer, is provided all around the light emitting element with the surface of the bump arranged on the electrode of the light emitting element as an opening. As a result, the light emitted from all sides of the light emitting device is efficiently absorbed by the fluorescent substances arranged in the surroundings, converted in wavelength, and then emitted. Therefore, a highly reliable white light emitting device can be obtained without the light emitting device being deteriorated by ultraviolet rays.

Further, as a fluorescent substance used in combination with a light emitting element capable of emitting ultraviolet light in order to obtain white light, in addition to the above, 3.5MgO.
0.5MgF ₂ · GeO ₂ : Mn, Mg ₆ As
₂ O ₁₁ : Mn, Gd ₂ O ₂ : Eu, LaO ₂ S: E
u, as a blue phosphor, Re ₅ (PO ₄ ) ₃ Cl: Eu
(However, Re is at least one selected from Sr, Ca, Ba, and Mg), BaMg ₂ Al ₁₆ O ₂₇ : Eu, etc. are preferably used. Since these fluorescent substances are remarkably excellent in light emission by ultraviolet light, a white light emitting device capable of emitting light with high brightness can be obtained.

In the present invention, the first positive electrode 4 is not particularly limited as long as it is an electrode material capable of making ohmic contact with the p-type nitride semiconductor layer. For example, Au, Pt, Al, Sn, C
One or more kinds of r, Ti, Ni, Co and the like can be used. Further, the first positive electrode can be adjusted to be translucent or opaque by adjusting the film thickness according to the mounting form, but in the present invention, the first positive electrode becomes translucent. The film thickness is adjusted so that To be transparent, the film thickness is 10
The thickness is set to angstrom to 500 angstrom, preferably 10 angstrom to 200 angstrom.

As the second positive electrode 5, Au, P
One or more kinds of metal materials such as t, Al, Sn, Cr, Ti and Ni can be used. The thickness of the second positive electrode is 1
It is preferably set to 000 angstrom to 2 μm.

In the present invention, the negative electrode 6 is not particularly limited as long as it is an electrode material capable of making ohmic contact with the n-type nitride semiconductor. For example, Ti, Al, Ni, Au, W, V
It is possible to use one or more kinds of metal materials such as
Ti / Al, W / A based on i, W, V respectively
It is preferable to have a multi-layer structure of 1 / W / Au, W / Al / W / Pt / Au, V / Al or the like. _Vf can be reduced by using an electrode material capable of making ohmic contact with the n-type nitride semiconductor layer. The film thickness of the negative electrode 7 is 2
000 angstrom to 5 μm, preferably 5000
Angstrom is set to ˜1.5 μm.

In the present invention, short circuit between positive and negative electrodes is prevented.
In order to prevent this, the bump formation surface of each electrode is used as an opening
It is preferable to provide an insulating protective film 7 on the surface of the conductor layer.
Yes. Also, an insulating protective film may be applied to the top surface of each electrode.
If it is formed like this, it peels off from the underlying layer where each electrode is in contact.
It is preferable because it can be suppressed. Material of insulating protective film
Has good transmittance at the main wavelength, and
Good adhesion to the electrode, second positive electrode, and negative electrode
There is no particular limitation. It also cuts light in the short wavelength range.
It is preferable to use a material that For example, alkali silicate
Lath, soda-lime glass, lead glass, barium glass, etc.
Glass composition or SiO_Two, TiO _Two, Ge
O_Two, And Ta_TwoO₅Oxides such as
It The film thickness is not particularly limited, but the main wave
It is preferable that the transmittance in the length is adjusted to 90% or more.
Good

(Bump) In the present invention, the light emitting element has at least one bump on the electrode, and the upper surface of the bump is substantially the same as the upper surface of the light-transmissive mold member disposed in contact with the side surface of the bump. It is a plane. As described above, by forming the substantially same plane on the upper surface of the bump and the upper surface of the translucent mold member, a light emitting device which is easy to mount and has high reliability can be obtained.

The bumps are first formed on the bonding surface of the electrodes of each element in the wafer state before the light emitting elements are individually cut (first step). When a metal material such as Au or Pt is used as the material of the bump, a bump having excellent adhesion to each electrode and conductivity can be obtained. The metal material is pressure-bonded and formed on each bonding surface with a bump bonder. When the protrusion portion generated at the central tip portion of the bump upper surface is pressed by a leveler to be flattened, a bump having a substantially equal width from the bottom surface side to the upper surface side can be formed. Moreover, the shape of the side surface of the bump can be adjusted by adjusting the pressing force. The side surface of the bump is preferably tapered, and the light emitted from the fluorescent material and the light emitting element in the light-transmissive mold member is reflected and scattered well on the side surface to improve the light extraction efficiency. it can.

In the case of the above-mentioned metal material, the bumps are 20-50.
It is preferably formed with a height of μm. It is also possible to form the bump into a thick film by using a material such as plating. For example, it can be formed by electroless Ni plating to a height of 5 to 150 μm. In addition, the bumps should be electroless Ni.
It is also possible to have a two-layer structure in which electroless Au plating is provided on the plating. For example, electroless Ni plating is 5-100μ
m height, and electroless A on the electroless Ni plating
It is preferable to form the u-plating at a height of 5000 angstroms or less, because the bonding property becomes good. A translucent mold member containing a fluorescent substance is provided on the semiconductor layer side of the element having the bumps formed in this way (second step), and the upper surface of the translucent mold member and the bump are considered in consideration of the particle diameter of the fluorescent substance. So that their upper surfaces are substantially flush with each other, and the thickness of the entire bump is 5 μm to 150 μm, preferably 5 μm to 10 μm.
The light-transmissive mold member and the bump are simultaneously polished so that the thickness becomes 0 μm, more preferably 50 μm to 100 μm to expose the surface of the bump (third step). In this way, by setting the height of the bumps in the above range, unevenness in color tone is suppressed, and a light emitting device having good optical characteristics can be obtained.

In the case of a light emitting element which has a pair of positive and negative electrodes on the same surface side and emits visible light like the light emitting element used in the present embodiment, the current density near the negative electrode becomes high and the color There is a tendency for unevenness to occur. In the present invention, a bump is provided on each electrode of the light-emitting element, and the upper surface of the bump is formed to be substantially flush with the upper surface of the light-transmissive mold member that is the light extraction surface. A light emitting device capable of improving color unevenness and emitting light uniformly can be obtained.

(Fluorescent substance) The fluorescent substance used in the light emitting device of the present invention is yttrium activated with cerium capable of emitting light by exciting light emitted from a semiconductor light emitting device having a nitride semiconductor as a light emitting layer. It is based on an aluminum oxide fluorescent material. As a specific yttrium-aluminum oxide-based fluorescent substance, YAlO
₃ : Ce, Y ₃ Al ₅ O ₁₂ Y: Ce (YAG: Ce)
And Y ₄ Al ₂ O ₉ : Ce, and a mixture thereof. At least one of Ba, Sr, Mg, Ca, and Zn may be contained in the yttrium-aluminum oxide-based fluorescent material. Further, by containing Si, the reaction of crystal growth can be suppressed and the particles of the fluorescent substance can be aligned.

In the present specification, the yttrium-aluminum oxide fluorescent material activated by Ce is to be interpreted in a broad sense, and a part or the whole of yttrium is composed of Lu, Sc, La, Gd and Sm. Substituted with at least one element selected from the group or partially or entirely of aluminum is Ba, Tl, Ga, I
It is used in a broad sense to include a phosphor having a fluorescent effect in which any one or both of n is substituted.

More specifically, the general formula (Y_zGd_1-z)
_ThreeAl₅O₁₂: Ce (where 0 <z ≦ 1)
Photoluminescent phosphors and general formulas (Re_1-aSm
_a) _ThreeRe ’₅O₁₂: Ce (where 0 ≦ a <1, 0 ≦
b ≦ 1, Re is selected from Y, Gd, La, Sc
At least one, Re 'is selected from Al, Ga, and In.
Is at least one. ) Photo Lumi
It is a luminescent phosphor.

Since this fluorescent substance has a garnet structure,
Resistant to heat, light and moisture, the peak of the excitation spectrum is 45
It can be set to around 0 nm. In addition, the emission peak has a broad emission spectrum in the vicinity of 580 nm and a tail of 700 nm.

Further, the photoluminescence phosphor contains 460 because Gd (gadolinium) is contained in the crystal.
The excited light emission efficiency in the long wavelength region of nm or more can be increased. Due to the increase in the content of Gd, the emission peak wavelength moves to the long wavelength and the entire emission wavelength also shifts to the long wavelength side.
That is, when a reddish emission color is required, it can be achieved by increasing the amount of Gd substitution. On the other hand, as Gd increases, the emission luminance of photoluminescence due to blue light tends to decrease. Further, if desired, in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, C
It is also possible to contain o, Ni, Ti, Eu and the like.

Moreover, in the composition of the yttrium-aluminum-garnet-based phosphor having the garnet structure, the emission wavelength is shifted to the short wavelength side by substituting a part of Al with Ga. Further, by replacing a part of Y in the composition with Gd, the emission wavelength shifts to the long wavelength side.

When a part of Y is replaced with Gd, the replacement with Gd is less than 10% and the content (replacement) of Ce is 0.0.
It is preferably from 3 to 1.0. Substitution with Gd is 2
If it is less than 50%, the green component is large and the red component is small,
By increasing the content of Ce, the red component can be supplemented, and a desired color tone can be obtained without lowering the brightness. With such a composition, the temperature characteristics are improved and the reliability of the light emitting diode can be improved. Further, by using a photoluminescent phosphor adjusted to have a large amount of red component, it is possible to form a light emitting device capable of emitting an intermediate color such as pink.

Such a photoluminescent phosphor is
As a raw material of Y, Gd, Al, and Ce, an oxide or a compound which easily becomes an oxide at high temperature is used, and these are sufficiently mixed in a stoichiometric ratio to obtain a raw material. Or Y, Gd,
A coprecipitated oxide obtained by firing a solution obtained by coprecipitating a rare earth element of Ce in an acid at a stoichiometric ratio with oxalic acid;
A mixed raw material is obtained by mixing with aluminum oxide. An appropriate amount of fluoride such as barium fluoride or ammonium fluoride is mixed with this as a flux and packed in a crucible.
The product is fired in a temperature range of 0 to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then the fired product is ball-milled in water and washed,
It can be obtained by separating, drying and finally sieving.

In the light emitting diode of the present invention, such a photoluminescent phosphor may be a mixture of yttrium-aluminum-garnet phosphor activated with two or more kinds of cerium and other phosphors.

In addition, as a phosphor capable of emitting red light by absorbing blue, blue-green or green, a sapphire (aluminum oxide) phosphor activated by Eu and / or Cr or Eu.
And / or nitrogen is activated with Cr-containing _Ca-Al 2 _{O 3}
-SiO ₂ phosphor (oxynitride fluorescent glass) and the like. It is also possible to obtain white light by mixing the light from the light emitting element and the light from the phosphor using these phosphors.

Further, the viscosity of the translucent mold member containing the phosphor and the particle size of the phosphor affect mass productivity during formation. That is, when the material forming the translucent mold member has a low viscosity or when the particle size of the phosphor is large, the separation and sedimentation tends to be promoted due to the difference in specific gravity from the material forming the translucent mold member. Also, due to crystal destruction in the crushing process,
The conversion efficiency of the inorganic phosphor tends to decrease as the particle size decreases. Further, if it is too small, the dispersibility in the translucent mold member is reduced due to the formation of aggregates, which tends to cause color unevenness and brightness unevenness from the light emitting device. Therefore, although depending on the material of the translucent mold member and the phosphor, the average particle size of the phosphor is preferably 1 to 100 μm, more preferably 5 to 50 μm. Here, the average particle size refers to the average particle size measured by a subsieve sizer based on the air permeation method as a basic principle.

In order to improve the light emission output, the average particle size of the fluorescent substance used in the present invention is 10 μm to 50 μm.
μm is preferable, and more preferably 15 μm to 30 μm. The fluorescent material having such a particle size has a high light absorption rate and a high conversion efficiency and a wide excitation wavelength range. In this way, by containing the large-diameter fluorescent substance having an optically excellent characteristic, it becomes possible to satisfactorily convert and emit light around the main wavelength of the light-emitting element, thereby increasing the mass productivity of the light-emitting device. Be improved.

Further, it is preferable that a fluorescent substance having this average particle size value is frequently contained, and the frequency value is 20.
% To 50% is preferable. By using such a fluorescent material having a small variation in particle size, it is possible to obtain a light emitting device having a good color tone with suppressed color unevenness.

As a specific fluorescent substance used in the present invention, a YAG type phosphor (Y, Lu, S activated by Ce) is used.
(Cerium-activated garnet-based phosphor containing at least one element selected from the group consisting of c, La, Gd, and Sm, and at least one element selected from the group consisting of Al, Ga, and In) I will give you. The YAG-based phosphor precipitates a solution of rare earth elements of Y, Gd, and Ce dissolved in an acid at a stoichiometric ratio with oxalic acid. The coprecipitated oxide obtained by firing this and aluminum oxide are mixed to obtain a mixed raw material. Ammonium fluoride as a flux is mixed with this and packed in a crucible.
A calcined product is obtained by partial calcining. The fired product can be ball-milled in water to be washed, separated, dried, and finally passed through a sieve to form a YAG-based phosphor.

Similarly, another specific phosphor used in the present invention is a nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ phosphor activated with Eu and / or Cr. Nitrogen-containing CaO-Al activated with this Eu and / or Cr
_{The 2} O ₃ -SiO ₂ phosphor is a powder obtained by mixing a raw material such as aluminum oxide, yttrium oxide, silicon nitride and calcium oxide with a rare earth raw material at a predetermined ratio in a nitrogen atmosphere at 1300 ° C to 1900 ° C (more preferably 150 ° C).
Melt and mold at 0 ° C to 1750 ° C). The molded product can be ball-milled, washed, separated, dried, and finally passed through a sieve to form a phosphor. This makes it 450
a Ca-Al-Si-O-N-based oxynitride fluorescent glass activated by Eu and / or Cr capable of emitting red light by an excitation spectrum having a peak at nm and a blue light having a peak at about 650 nm; can do.

C activated by Eu and / or Cr
The peak of the emission spectrum can be continuously shifted from 575 nm to 690 nm by increasing or decreasing the nitrogen content of the a-Al-Si-O-N oxynitride fluorescent glass. Similarly, the excitation spectrum can be continuously shifted. Therefore, white light can be emitted by the combined light of the light from the gallium nitride-based compound semiconductor containing the light emitting layer of GaN or InGaN doped with impurities such as Mg and Zn and the light of the phosphor of about 580 nm. In particular, I can emit light of about 490 nm with high brightness.
It is also possible to obtain light emission ideally in combination with a light emitting device made of a gallium nitride-based compound semiconductor containing nGaN in the light emitting layer.

In addition, the above-mentioned Ce-activated YAG-based phosphor and Eu and / or Cr-activated nitrogen-containing Ca-
Utilizing a light-emitting element capable of emitting blue light by combining with Al-Si-O-N oxynitride fluorescent glass, light emission with extremely high color rendering including RGB (red, green, blue) components with high brightness It is also possible to form a diode. Therefore, an arbitrary intermediate color can be formed very simply by adding a desired pigment. In the present invention, all the phosphors are inorganic phosphors, and it is possible to form a light emitting diode having both high contrast and excellent mass productivity by utilizing an organic light scattering agent, SiO _2, or the like.

(Translucent Mold Member) Such a fluorescent substance is contained in the translucent mold member. As a material of the translucent mold member, a material having high light resistance to light from the light emitting element and the fluorescent substance and excellent translucency is preferable.
When it works as a protective film for covering the light emitting element,
A certain level of rigidity is required. As the material of the translucent mold member, specifically, epoxy resin, silicone resin,
Suitable examples include solventless liquid translucent thermosetting resins such as urethane resins, unsaturated polyester resins, acrylic urethane resins, and polyimide resins. Similarly, a solvent type liquid translucent thermoplastic resin such as an acrylic resin, a polycarbonate resin or a polynorbornene resin can be used. Further, not only an organic substance but also an inorganic substance such as silicon dioxide, or a hybrid resin in which silicon dioxide formed by a sol-gel method and an acrylic resin are mixed can be preferably used. When the translucent mold member such as the convex lens member is further covered with a resin or the like, the resin described above can be selected and used in consideration of the adhesion to the convex lens member or the like.

In the present invention, the translucent mold member 9 containing the fluorescent substance is provided on the upper surface and the side surface of the element in a wafer state. By doing this in the wafer state,
After that, polishing can be performed to adjust to a preferable film thickness, and a light-emitting device having an ideal color tone can be formed.
In addition, when the translucent mold member containing the fluorescent substance is provided so as to cover the side surface of the element, the light from the side surface of the element can be color-converted and emitted, and uneven color tone can be suppressed. In addition, the light emitting diode of the present invention,
Since there is nothing necessary for electrical connection such as a wire in the translucent mold member containing the fluorescent substance, there is nothing that blocks light and the light extraction efficiency is good.

In the present invention, the upper surface of the light-transmissive mold member serving as the light emitting surface is substantially flush with the upper surface of the bump on the electrode of the light emitting element. Here, in this specification, the term “substantially the same plane” is used in a broad sense as long as the entire side surface of the bump is coated with the light-transmissive mold resin. By covering the bumps with the translucent mold member without exposing the side surfaces thereof, it is possible to prevent moisture from being absorbed from the interface between the bump and the translucent mold member. preferable. Further, the shape of the upper surface of the mold member is not particularly limited and may be curved or may have irregularities. In such a configuration, a lens effect can be obtained and good directional characteristics can be obtained. Is obtained.

In the light emitting device thus obtained, it is assumed that the upper face of the light emitting device composed of the upper surface of the bump 8 and the translucent mold member 9 containing the fluorescent substance is substantially parallel to the substrate side bottom surface of the light emitting device. Various implementations are possible, which is preferable. Furthermore, it is preferable that the light emitting device is a substantially rectangular parallelepiped, because a plurality of light emitting devices can be easily mounted densely. In particular, when using a light emitting device having both electrodes on the same surface side, by providing bumps on each of the electrodes and setting the conductive connection portions of the positive and negative electrodes at the same height from the device bottom surface side, the lead electrode, etc. When the external electrodes and the light emitting device are electrically conductive by wires, the loop shape and the approach angle of each wire can be made equal. This improves the strength of the wire and prevents the wire from breaking due to external force or the like.

Further, as shown in FIG. 5, the translucent mold member containing the fluorescent material is formed so that the upper surface of the bump provided on each electrode of the light emitting element serves as an opening to cover the periphery of the light emitting element. It may be provided on all sides. With this structure, all the light emitted from the light emitting element can be converted satisfactorily, and a light emitting device capable of uniformly emitting light can be obtained. In particular, if a translucent mold member containing a fluorescent substance is provided on the bottom surface of the substrate side, flip mounting becomes possible and the output can be improved. On the other hand, when the substrate side of the light emitting device is opposed to the mounting substrate and fixed with a die bond resin, the fluorescent substance is contained in the die bond resin to satisfactorily convert the light emitted from the substrate bottom side of the light emitting element. Can be taken out.

(Reflective Film) The reflective film 11 used in the present invention.
Is for suppressing the emission of light emitted from the substrate side to the outside to improve the light extraction efficiency and to obtain better light emission. Examples of preferable materials for the reflective film include an oxide film formed of a multilayer film and various metals. It is particularly preferable to use a metal film from the viewpoint of ease of formation. As the metal film, specifically, Ag or A having high reflectance
1 and alloys thereof. These metal films can be formed by a sputtering method, a vacuum vapor deposition method, or the like. In the present invention, the reflective film may be formed so as to cover at least the bottom surface of the substrate, and is preferably continuously formed so as to cover the side surface and the bottom surface of the chip.

[0063]

EXAMPLES The light emitting diodes of the examples according to the present invention will be described below. The present invention is not limited to the examples shown below.

[Example 1] Each semiconductor layer 2, 3 and blue (470n) were formed on an insulating substrate 1 made of sapphire (C plane).
m) is a light emitting layer (not shown) capable of emitting light.
It is formed by the E method. After annealing, the wafer is taken out of the reaction container, an insulating film made of a predetermined SiO ₂ or the like is formed on the surface of the uppermost p-type nitride semiconductor layer, and then a resist film having a predetermined shape is formed on the surface of the insulating film. Form and RI
Etching is performed from the p-type nitride semiconductor layer side with an E (reactive ion etching) device to expose the surface of the n-type nitride semiconductor layer forming the negative electrode. Next, after peeling off the insulating film with an acid, the first positive electrode 4 made of Ni / Au is formed on almost the entire surface of the p-type nitride semiconductor layer, which is the uppermost layer, by 47.
The light transmittance at a wavelength of 0 nm is 40% and the surface resistivity is 2
The film thickness is 200 angstrom so that it becomes Ω / □. Next, a second positive electrode 5 made of Au is formed on the first positive electrode by a lift-off method so as to have a film thickness of 0.7 μm. On the other hand, on the surface of the n-type nitride semiconductor layer exposed by etching, W / Al /
The negative electrode 6 made of W / Au is formed with a film thickness of 0.8 μm,
LED element.

Next, patterning is performed to expose only the bonding portion of each electrode and cover the entire element with SiO 2.
_The insulating protective film 7 made of 2 is formed with a film thickness of 2 μm so that the light transmittance is 90% at a wavelength of 470 nm.

In the nitride semiconductor wafer formed as described above, as shown in FIG. 3- (a), a recess for forming a fluorescent substance-containing translucent mold member is formed on the side surface of the semiconductor layer by dicing. . By performing dicing in this way, it is possible to dispose a translucent mold member containing a fluorescent substance on the side surface of the light emitting layer of the light emitting element and suppress color unevenness, which is preferable. Further, when the wafer is scribed, the pressure applied to the wafer can be reduced, and the warp and cleavage of the substrate can be suppressed. After dicing, Au, which is the material of the bumps 8, is pressed onto each bonding surface of each electrode with a bump bomber at a height of 50 μm. (First step).

On the other hand, as a fluorescent substance (Y _0.8 Gd
_0.2 ) ₃ Al ₅ O ₁₂ : Ce 80 parts by weight, epoxy resin 100 parts by weight and acid anhydride, curing accelerator and SiO ₂ as a curing accelerator and a diffusing agent are sufficiently stirred at 65 ° C., and a fluorescent substance-containing translucent light is transmitted. A material to be the elastic mold member 9 is formed. The viscosity of the epoxy resin at this time is 700 cp. The material for the translucent mold member containing the fluorescent substance thus formed is formed into a film having a thickness of 1 so as to cover the bumps by dipping.
Coat with 50 μm (second step). 85 ℃ 1
It is cured by primary curing for 80 minutes and secondary curing at 140 ° C. for 240 minutes.

Next, the bumps 8 and the translucent mold member 9 containing the fluorescent substance are polished together from the semiconductor layer side so that the upper surface of the translucent mold member from the light emitting surface of the light emitting element is 40 μm. The surface of 8 is exposed (3rd process). Further, the substrate is ground and polished from the substrate side so that the thickness becomes 120 μm.

Finally, the translucent mold member at the position where the nitride semiconductor wafer is to be cut is removed by dicing, and then a scribe line is pulled by a scriber to cut it into chips of 300 μm square by an external force (fourth step). .

When a white LED lamp is formed using the light emitting diode formed as described above, the yield is 95%. Thus, by using the light emitting diode of the present invention, it is possible to produce a light emitting device with good mass productivity,
A light-emitting device with high reliability and less unevenness in color tone can be provided.

(Comparative Example 1) On the other hand, after the insulating film is provided, the nitride semiconductor layer semiconductor wafer is cut into chips, and the individual light emitting elements are arranged on the inner bottom surface of the mount lead cup and electrically connected by wires. After the connection, the light emitting diode is formed in the same manner as in Example 1 except that the fluorescent substance-containing translucent mold member is first filled in the cup so as to cover the light emitting element, and then the translucent convex lens member is provided. Then, the yield is 85%. Further, in comparison with the light emitting diode of Example 1, uneven color tone is seen.

(Example 2) After the fourth step, the reflection film 11 is formed on the sapphire substrate side by the sputtering method using the sheet expand 10 for each light emitting diode.
When the light emitting diode is formed in the same manner as in Example 1 except that the above step is performed, the same effect as in Example 1 can be obtained. In addition, the light from the end face can be satisfactorily taken out to the light emitting surface, and a high output light emitting diode can be obtained.

(Embodiment 3) After the fourth step, the light emitting diode is manufactured in the same manner as in the embodiment 1 except that a light-transmissive mold member containing a fluorescent substance is formed around the substrate from the substrate side in each light emitting diode. When the above is formed, a light emitting device having the translucent mold member containing the fluorescent substance on the entire outer periphery except the exposed surface of the bump provided on the light emitting element is obtained, and the same effect as in Example 1 can be obtained. Since light emitted from all sides of the light emitting element can be favorably converted in color, color unevenness is suppressed and more uniform light emission can be obtained.

On the other hand, as a fluorescent substance (Y _0.8 Gd
_0.2 ) ₃ Al ₅ O ₁₂ : Ce (80 parts by weight), silanol (Si (OEt) 3OH) 100 parts by weight, and ethanol at a weight twice that of the silanol are mixed to form a slurry. After being ejected from the nozzle onto the wafer and applied with the material of the translucent mold member containing the fluorescent substance, it is heated at 300 ° C. for 3 hours to convert silanol into SiO 2.
When the light emitting device is formed in the same manner as in Example 1 except that the fluorescent substance is fixed on the wafer, the same effects as in Example 1 can be obtained.

[0075]

As described in detail, in the light emitting device according to the present invention, before cutting the wafer into chips, bumps are formed on each electrode to raise the conductive portion, and the fluorescent substance-containing translucent light is transmitted. By providing the conductive mold member on the semiconductor layer side, a color conversion type light emitting device having high reliability and excellent optical characteristics can be efficiently produced.

Further, since the light emitting device of the present invention has the translucent mold member containing the fluorescent substance on the entire surface of the light emitting element with the exposed bump surface as the opening, the light from the light emitting element can be efficiently emitted by the fluorescent substance. It can be converted, and a desired color tone can be uniformly emitted. Therefore, external deterioration due to light from the light emitting element can be suppressed.

Further, by providing a continuous insulating reflection film on the substrate side, a light emitting device having good light extraction efficiency and less uneven light emission can be obtained.

[Brief description of drawings]

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

FIG. 2 is a schematic plan view of a light emitting diode according to another aspect of the embodiment of the present invention.

FIG. 3 is a method of forming a light emitting diode according to an embodiment of the present invention.

FIG. 4 is a step of another method for forming a light emitting diode according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of another light emitting diode according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Substrate 2 ... N-type nitride semiconductor layer 3 ... p-type nitride semiconductor layer 4 ... 1st positive electrode 5 ... Second positive electrode 6 ... Negative electrode 7 ... Insulating film 8 ... Bump 9 ... Translucent mold member containing fluorescent substance 10-Sheet Expand 11 ... Reflective film

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 20, 2003 (2003.1.2
0)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Light emitting device

[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 that can be used for a liquid crystal backlight, an illumination light source, various indicators, traffic lights, etc., and relates to a semiconductor light emitting element and a fluorescent substance capable of emitting light having a wavelength longer than that of the semiconductor light emitting element. And a long wavelength conversion type light emitting device having

[0002]

2. Description of the Related Art Today, semiconductors capable of emitting blue light with high brightness
Nitride semiconductor (In _xGa_yAl
_1-xyLED using N, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1)
The chip was developed. Light emitting device using nitride semiconductor
Used other materials such as GaAs and AlInGaP.
Higher output than light-emitting elements that emit red to yellow-green
In addition, the color shift due to temperature is small.
Although, to date, it has wavelengths above green
It tends to be difficult to obtain high output in the long wavelength region.
On the other hand, emitted from the LED chip on this LED chip
Absorbs at least part of the blue light and emits yellow light
A fluorescent substance such as YAG: Ce fluorescent substance
Has developed a light emitting diode that can emit white light.
It was (International publication number WO98 / 5078) This light emitting diode is, for example, a mount lead cup.
The LED chip is arranged on the inner bottom part and
The mount lead and the inner lead are made of gold wire or the like.
Electrical connection. After connecting, the LED
And absorbs the blue light from the
Fill with a translucent mold resin containing a fluorescent substance that emits light.
It Finally, project the tip of both leads with a transparent resin.
Form a lens. In this way, the LED chip and the firefly
White light, which is a mixture of light and light, passes through a convex lens.
An LED lamp that emits light is obtained.

In the above LED lamp, a light-transmissive mold resin containing a fluorescent material is provided around the chip in advance, and then a convex lens member is formed from the light-transmissive resin or the like. As a result, the light from the chip becomes a desired color-mixed light when it passes through the translucent mold resin containing the fluorescent substance filled in the cup. Therefore, the color-converted light can be extracted favorably in the front direction. Further, by adjusting the shape of the cup, it is possible to suppress light scattering and improve the light emission output, and it is possible to easily obtain desired light emission characteristics.

[0004]

However, in such an LED lamp, it has been difficult to produce the LED lamp in a high yield with conspicuous emission unevenness and chromaticity variation as the size of the LED lamp becomes smaller.

Therefore, it is an object of the present invention to provide a chip type long wavelength conversion type light emitting device having good productivity and excellent optical characteristics, and a method for forming the same.

[0006]

That is, in a light emitting device according to the present invention, a light emitting element having a semiconductor layer on a substrate and a light having a different wavelength by absorbing a part of the light from the light emitting element emits light. A light emitting device having a possible fluorescent substance and a color conversion member containing the fluorescent substance, wherein at least one bump is provided on an electrode of the light emitting element, and the color is provided on at least a part of a side surface of the bump. A conversion member is provided, and a side surface of the bump has a tapered shape. As a result, it is possible to obtain a light emitting device that improves the light extraction efficiency, has high reliability, and is capable of uniformly emitting a desired mixed color light.

Further, the color conversion member may cover the periphery of the light emitting element. With this configuration, all the light emitted from the light emitting element can be converted satisfactorily,
A light emitting device that can emit light uniformly can be obtained.

Further, the light emitting element may have the color conversion member on the bottom surface on the substrate side. By providing a fluorescent material-containing color conversion member also on the bottom surface of the substrate side, it is possible to improve output when flip mounting is performed.

The light emitting element may be fixed by the color conversion member with the substrate side facing the mounting substrate. By including a fluorescent substance in the die-bonding resin, the light emitted from the bottom surface of the substrate of the light emitting element can be favorably wavelength-converted and taken out to the outside.

The thickness of the bumps is 5 μm to 150 μm.
μm. As a result, a light emitting device capable of emitting light with high output is obtained.

The upper surface of the light emitting device, which is composed of the upper surface of the bump and the upper surface of the translucent mold member, is substantially parallel to the bottom surface on the substrate side. As a result, a light emitting device having good directional characteristics can be obtained.

The fluorescent substance is a yttrium-aluminum-garnet-based fluorescent substance activated by Ce, Eu.
And / or nitrogen-containing been activated with Cr _CaO-Al 2 O
It is one type selected from _3- SiO ₂ . As a result, it is possible to obtain a simple and highly reliable light emitting device capable of emitting mixed light with high brightness.

Further, the invention is characterized in that it has a continuous reflection film on at least the substrate side of the light emitting element. This makes it possible to obtain a light emitting device having good light emitting efficiency and less uneven brightness.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of various experiments, the inventor of the present invention provided a light-transmissive mold member containing a fluorescent substance, which is a color conversion member, before electrically connecting the elements, so that the subsequent mounting process was performed. It has been found that a color conversion type light emitting device which can be simplified and has high reliability is obtained, and the present invention has been completed.

Conventionally, in the case of forming a wavelength conversion type LED lamp, it was necessary to previously provide a fluorescent material-containing mold member separately from the convex lens member for each element divided. Specifically, the following process is required.

After placing each chip-shaped element on the bottom of the mount lead in the cup and electrically connecting each electrode of the element to the lead electrode with a wire or the like, first, the element is placed in the cup so as to cover the element and the wire. A resin containing a fluorescent substance is dropped and injected by a dispenser or the like, and heat-cured to form a color conversion member. In this way, the first mold member is formed.

Thereafter, the resin, which is the material of the convex lens member, is poured into the casting case, and the leading end portion of the lead on which the color conversion member is formed is immersed and arranged. By placing this in an oven and curing it by heating, a convex lens member, which is a second mold member, is formed, and the wavelength-convertable L
An ED lamp is formed.

In order to form one light emitting device as described above, the step of filling each element with resin and curing it is required twice, and the waiting time for the resin effect is comparatively long, and further production is performed. The improvement of the sex is desired.

Further, as the size of the light emitting device becomes smaller, the amount of the first mold member inevitably becomes smaller, and it is difficult to arrange the amount of the fluorescent substance necessary for obtaining the desired mixed color light with high accuracy for each element. It was extremely difficult, and the chromaticity variation occurred in each light emitting device, and the yield was poor.

Further, the light emitting device has a wire or the like in the color conversion member in order to provide the color conversion member after electrically connecting the light emitting element with the semiconductor layer as the upper surface. It is considered that such an electrical connection member adversely affects the arrangement of the fluorescent substance, reduces the light extraction efficiency of the fluorescent substance and the light emitting element, and causes color unevenness and output reduction.

Therefore, in the present invention, in order to solve the above problems, a color conversion member is provided in the light emitting element itself. Specifically, the electrode portion of the light emitting element is raised in a wafer state before being divided into individual light emitting elements, and a color conversion member is provided around the light emitting elements. With such a configuration, it is possible to form a color conversion type light emitting device having sufficiently high reliability and excellent optical characteristics with high productivity.

Embodiments according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a light emitting diode according to an embodiment of the present invention. At least an n-type nitride semiconductor layer 2, an active layer (not shown), and a p-type nitride semiconductor layer 3 are sequentially stacked on an insulating substrate 1, and the p-type nitride semiconductor layer 3 is formed on almost the entire surface. The formed transparent first positive electrode 4, the second positive electrode 5 for bonding formed on a part of the first positive electrode 4, and exposed from the p-type nitride semiconductor layer 3 side by etching or the like. A light emitting element having a negative electrode 6 on the n-type nitride semiconductor layer 2 and having an insulating protective film 7 formed except for the bonding surface of each electrode is used. Bumps 8 are provided on the bonding surfaces of the respective electrodes of such a light emitting element, and the upper surfaces of these bumps are exposed so that the light-transmitting mold member 9 containing a fluorescent substance is provided on the upper surface and side surface of the light emitting element on the semiconductor layer side. It is provided. Hereinafter, each configuration of the present invention will be described in detail. (Light Emitting Element) In the present invention, it is efficient that the light from the light emitting element has a shorter wavelength than the light emitted from the fluorescent substance. Therefore, as capable of emitting semiconductor elements high visible light emission luminance with high efficiency, a nitride semiconductor (In _x Ga _y A
Preferable examples are those in which 1 _1−x−y N, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) is used for the active layer. A light emitting device using a nitride semiconductor includes a sapphire substrate and a spinel (MgAi).
_Although it can be formed on a ₂ O ₄ ) substrate, SiC, GaN single crystal, or the like, it is preferable to use a sapphire substrate to satisfy mass productivity and crystallinity. Therefore, in the present invention, the light emitting element in which the n-type and p-type nitride semiconductor layers are formed on the sapphire substrate which is an insulating substrate and which has both electrodes on the semiconductor layer side is used.

More specifically, the light emitting device comprises an n-type nitride semiconductor layer 2 composed of one or more layers, an active layer (not shown), and one or more layers on a sapphire substrate 1. The p-type nitride semiconductor layer 3 is laminated, and positive and negative electrodes are formed as follows. That is, the positive electrode is composed of the first positive electrode 4 formed on almost the entire surface of the p-type nitride semiconductor layer and the second positive electrode 5 for bonding formed on a part of the first positive electrode. The negative electrode 6 is formed on the surface of the n-type nitride semiconductor layer exposed by removing a part of the p-type nitride semiconductor layer by dry etching or the like.

In the present invention, the n-type nitride semiconductor layer 2 and the p-type nitride semiconductor layer 3 are not particularly limited, and any layer structure may be used.

When the white light is emitted in the light emitting device of the present invention, the main emission peak of the light emitting element is 400 nm or more 53 in consideration of the complementary color relation with the fluorescent material, the deterioration of the resin, and the like.
It is preferably 0 nm or less, and more preferably 420 nm or more and 490 nm or less. In order to improve the efficiency of each of the light emitting device and the fluorescent substance, 450 nm or more and 470 nm or more
It is more preferable to use a light emitting device having a main emission peak below.

On the other hand, in the light-emitting device of the present invention, when the light-emitting element has a light-transmissive mold member containing a fluorescent substance, resin or glass relatively resistant to ultraviolet rays is used.
It is also possible to obtain a light emitting device capable of emitting white light by using a light emitting element capable of emitting ultraviolet light having a short emission wavelength near 00 nm as a main emission peak. Due to such short wavelength light, red,
Phosphors that can fluoresce in blue and green, such as Y ₂ O ₂ S: Eu as a red phosphor and Sr ₅ (PO as a blue phosphor)
₄ ) ₃ Cl: Eu, and as a green phosphor (SrEu)
White light can be obtained by including O.Al ₂ O ₃ in the ultraviolet resistant resin or the like and applying it as a color conversion layer on the surface of a light emitting device emitting short wavelength light.

In one embodiment of the present invention, a light-transmissive mold member, which is a color conversion layer, is provided all around the light emitting element with the surface of the bump arranged on the electrode of the light emitting element as an opening. As a result, the light emitted from all sides of the light emitting device is efficiently absorbed by the fluorescent substances arranged in the surroundings, converted in wavelength, and then emitted. Therefore, a highly reliable white light emitting device can be obtained without the light emitting device being deteriorated by ultraviolet rays.

Further, as a fluorescent substance used in combination with a light emitting element capable of emitting ultraviolet light in order to obtain white light, in addition to the above, 3.5MgO.
0.5MgF ₂ · GeO ₂ : Mn, Mg ₆ As
₂ O ₁₁ : Mn, Gd ₂ O ₂ : Eu, LaO ₂ S: E
u, as a blue phosphor, Re ₅ (PO ₄ ) ₃ Cl: Eu
(However, Re is at least one selected from Sr, Ca, Ba, and Mg), BaMg ₂ Al ₁₆ O ₂₇ : Eu, etc. are preferably used. Since these fluorescent substances are remarkably excellent in light emission by ultraviolet light, a white light emitting device capable of emitting light with high brightness can be obtained.

In the present invention, the first positive electrode 4 is not particularly limited as long as it is an electrode material capable of making ohmic contact with the p-type nitride semiconductor layer. For example, Au, Pt, Al, Sn, C
One or more kinds of r, Ti, Ni, Co and the like can be used. Further, the first positive electrode can be adjusted to be translucent or opaque by adjusting the film thickness according to the mounting form, but in the present invention, the first positive electrode becomes translucent. The film thickness is adjusted so that To be transparent, the film thickness is 10
The thickness is set to angstrom to 500 angstrom, preferably 10 angstrom to 200 angstrom.

As the second positive electrode 5, Au, P
One or more kinds of metal materials such as t, Al, Sn, Cr, Ti and Ni can be used. The thickness of the second positive electrode is 1
It is preferably set to 000 angstrom to 2 μm.

In the present invention, the negative electrode 6 is not particularly limited as long as it is an electrode material capable of making ohmic contact with the n-type nitride semiconductor. For example, Ti, Al, Ni, Au, W, V
It is possible to use one or more kinds of metal materials such as
Ti / Al, W / A based on i, W, V respectively
It is preferable to have a multi-layer structure of 1 / W / Au, W / Al / W / Pt / Au, V / Al or the like. _Vf can be reduced by using an electrode material capable of making ohmic contact with the n-type nitride semiconductor layer. The film thickness of the negative electrode 7 is 2
000 angstrom to 5 μm, preferably 5000
Angstrom is set to ˜1.5 μm.

In the present invention, short circuit between positive and negative electrodes is prevented.
In order to prevent this, the bump formation surface of each electrode is used as an opening
It is preferable to provide an insulating protective film 7 on the surface of the conductor layer.
Yes. Also, an insulating protective film may be applied to the top surface of each electrode.
If it is formed like this, it peels off from the underlying layer where each electrode is in contact.
It is preferable because it can be suppressed. Material of insulating protective film
Has good transmittance at the main wavelength, and
Good adhesion to the electrode, second positive electrode, and negative electrode
There is no particular limitation. It also cuts light in the short wavelength range.
It is preferable to use a material that For example, alkali silicate
Lath, soda-lime glass, lead glass, barium glass, etc.
Glass composition or SiO_Two, TiO _Two, Ge
O_Two, And Ta_TwoO₅Oxides such as
It The film thickness is not particularly limited, but the main wave
It is preferable that the transmittance in the length is adjusted to 90% or more.
Good (Bump) In the present invention, the light emitting element is less
Both have one bump and the upper surface of the bump is
The upper surface of the translucent mold member that is placed in contact with the side surface of the
And the same plane. In this way, the upper surface of the bump and the transparent
The upper surface of the optical molding member should be approximately flush with the surface.
Has provided a light emitting device that is easy to mount and has high reliability.
Be done.

The bumps are first formed on the bonding surface of the electrodes of each element in the wafer state before the light emitting elements are individually cut (first step). When a metal material such as Au or Pt is used as the material of the bump, a bump having excellent adhesion to each electrode and conductivity can be obtained. The metal material is pressure-bonded and formed on each bonding surface with a bump bonder. When the protrusion portion generated at the central tip end portion of the bump upper surface is pressed by the leveler to be flattened, a bump having a substantially equal width from the bottom surface side to the upper surface side can be formed. Moreover, the shape of the side surface of the bump can be adjusted by adjusting the pressing force. The side surface of the bump is preferably tapered, and the light emitted from the fluorescent material and the light emitting element in the translucent mold member is reflected and scattered well on the side surface to improve the light extraction efficiency. it can.

In the case of the above-mentioned metal material, the bumps are 20-50.
It is preferably formed with a height of μm. It is also possible to form the bump into a thick film by using a material such as plating. For example, it can be formed by electroless Ni plating to a height of 5 to 150 μm. In addition, the bumps should be electroless Ni.
It is also possible to have a two-layer structure in which electroless Au plating is provided on the plating. For example, electroless Ni plating is 5-100μ
m height, and electroless A on the electroless Ni plating
It is preferable to form the u-plating at a height of 5000 angstroms or less, because the bonding property becomes good. A translucent mold member containing a fluorescent substance is provided on the semiconductor layer side of the element having the bumps formed in this way (second step), and the upper surface of the translucent mold member and the bump are considered in consideration of the particle diameter of the fluorescent substance. So that their upper surfaces are substantially flush with each other, and the thickness of the entire bump is 5 μm to 150 μm, preferably 5 μm to 10 μm.
The light-transmissive mold member and the bump are simultaneously polished so that the thickness becomes 0 μm, more preferably 50 μm to 100 μm to expose the surface of the bump (third step). In this way, by setting the height of the bumps in the above range, unevenness in color tone is suppressed, and a light emitting device having good optical characteristics can be obtained.

In the case of a light emitting element which has a pair of positive and negative electrodes on the same surface side and emits visible light, like the light emitting element used in the present embodiment, the current density near the negative electrode becomes high and the color There is a tendency for unevenness to occur. In the present invention, a bump is provided on each electrode of the light-emitting element, and the upper surface of the bump is formed to be substantially flush with the upper surface of the light-transmissive mold member that is the light extraction surface. A light emitting device capable of improving color unevenness and emitting light uniformly can be obtained. (Fluorescent substance) The fluorescent substance used in the light emitting device of the present invention is a yttrium-aluminum oxide activated with cerium which can emit light by exciting light emitted from a semiconductor light emitting element having a nitride semiconductor as a light emitting layer. It is based on a fluorescent substance.

As a specific yttrium-aluminum oxide-based phosphor, YAlO ₃ : Ce, Y ₃ Al ₅
O ₁₂ Y: Ce (YAG: Ce) and Y ₄ Al ₂ O ₉ : C
e, and a mixture of these. Ba, Sr, M for yttrium-aluminum oxide type phosphor
At least one of g, Ca, and Zn may be contained. Further, by containing Si, the reaction of crystal growth can be suppressed and the particles of the fluorescent substance can be aligned.

In the present specification, the yttrium-aluminum oxide fluorescent substance activated by Ce is to be interpreted in a broad sense, and a part or the whole of yttrium is composed of Lu, Sc, La, Gd and Sm. Substituted with at least one element selected from the group or partially or entirely of aluminum is Ba, Tl, Ga, I
It is used in a broad sense to include a phosphor having a fluorescent effect in which any one or both of n is substituted.

More specifically, the general formula (Y _z Gd _1-z ) ₃ A
l ₅ O _12: Ce (where, 0 <z ≦ 1) photoluminescence phosphor and the general formula represented by _{(Re 1-a Sm a)} 3 Re
' ₅ O ₁₂ : Ce (where 0 ≦ a <1, 0 ≦ b ≦ 1, Re
Is at least one selected from Y, Gd, La, and Sc, and Re ′ is at least one selected from Al, Ga, and In. ) Is a photoluminescent phosphor.

Since this fluorescent substance has a garnet structure,
Resistant to heat, light and moisture, the peak of the excitation spectrum is 45
It can be set to around 0 nm. In addition, the emission peak has a broad emission spectrum in the vicinity of 580 nm and a tail of 700 nm.

In addition, the photoluminescent phosphor contains 460 (Gd (gadolinium)) in the crystal so that
The excited light emission efficiency in the long wavelength region of nm or more can be increased. Due to the increase in the content of Gd, the emission peak wavelength moves to the long wavelength and the entire emission wavelength also shifts to the long wavelength side.
That is, when a reddish emission color is required, it can be achieved by increasing the amount of Gd substitution. On the other hand, as Gd increases, the emission luminance of photoluminescence due to blue light tends to decrease. Further, if desired, in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, C
It is also possible to contain o, Ni, Ti, Eu and the like.

Moreover, in the composition of the yttrium-aluminum-garnet-based phosphor having a garnet structure, the emission wavelength is shifted to the short wavelength side by substituting a part of Al with Ga. Further, by replacing a part of Y in the composition with Gd, the emission wavelength shifts to the long wavelength side.

When a part of Y is replaced with Gd, the replacement with Gd is less than 10% and the content (replacement) of Ce is 0.0.
It is preferably from 3 to 1.0. Substitution with Gd is 2
If it is less than 50%, the green component is large and the red component is small,
By increasing the content of Ce, the red component can be supplemented, and a desired color tone can be obtained without lowering the brightness. With such a composition, the temperature characteristics are improved and the reliability of the light emitting diode can be improved. Further, by using a photoluminescent phosphor adjusted to have a large amount of red component, it is possible to form a light emitting device capable of emitting an intermediate color such as pink.

Such a photoluminescent phosphor is
An oxide or a compound that easily becomes an oxide at high temperature is used as a raw material of Y, Gd, Al, and Ce, and they are sufficiently mixed in a stoichiometric ratio to obtain a raw material. Or Y, Gd,
A coprecipitated oxide obtained by firing a solution obtained by coprecipitating a rare earth element of Ce in an acid at a stoichiometric ratio with oxalic acid;
A mixed raw material is obtained by mixing with aluminum oxide. An appropriate amount of fluoride such as barium fluoride or ammonium fluoride is mixed with this as a flux and packed in a crucible.
The product is fired in a temperature range of 0 to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then the fired product is ball-milled in water and washed,
It can be obtained by separating, drying and finally sieving.

In the light emitting diode of the present invention, such a photoluminescent phosphor may be a mixture of yttrium-aluminum-garnet phosphor activated with two or more kinds of cerium and other phosphors.

Other phosphors capable of emitting red light by absorbing blue, blue-green and green are sapphire (aluminum oxide) phosphor activated by Eu and / or Cr and Eu.
And / or nitrogen is activated with Cr-containing _Ca-Al 2 _{O 3}
-SiO ₂ phosphor (oxynitride fluorescent glass) and the like. It is also possible to obtain white light by mixing the light from the light emitting element and the light from the phosphor using these phosphors.

Further, the viscosity of the translucent mold member containing the phosphor and the particle size of the phosphor affect mass productivity during formation. That is, when the material forming the translucent mold member has a low viscosity or when the particle size of the phosphor is large, the separation and sedimentation tends to be promoted due to the difference in specific gravity from the material forming the translucent mold member. Also, due to crystal destruction in the crushing process,
The conversion efficiency of the inorganic phosphor tends to decrease as the particle size decreases. Further, if it is too small, the dispersibility in the translucent mold member is reduced due to the formation of aggregates, which tends to cause color unevenness and brightness unevenness from the light emitting device. Therefore, although depending on the material of the translucent mold member and the phosphor, the average particle size of the phosphor is preferably 1 to 100 μm, more preferably 5 to 50 μm. Here, the average particle size refers to the average particle size measured by a subsieve sizer based on the air permeation method as a basic principle.

In order to improve the light emission output, the average particle size of the fluorescent substance used in the present invention is 10 μm to 50 μm.
μm is preferable, and more preferably 15 μm to 30 μm. The fluorescent material having such a particle size has a high light absorption rate and a high conversion efficiency and a wide excitation wavelength range. In this way, by containing the large-diameter fluorescent substance having an optically excellent characteristic, it becomes possible to satisfactorily convert and emit light around the main wavelength of the light-emitting element, thereby increasing the mass productivity of the light-emitting device. Be improved.

Further, it is preferable that the fluorescent substance having this average particle size value is contained frequently, and the frequency value is 20.
% To 50% is preferable. By using such a fluorescent material having a small variation in particle size, it is possible to obtain a light emitting device having a good color tone with suppressed color unevenness.

As a specific fluorescent substance used in the present invention, a YAG type phosphor (Y, Lu, S activated by Ce) is used.
(Cerium-activated garnet-based phosphor containing at least one element selected from the group consisting of c, La, Gd, and Sm, and at least one element selected from the group consisting of Al, Ga, and In) I will give you. The YAG-based phosphor precipitates a solution of rare earth elements of Y, Gd, and Ce dissolved in an acid at a stoichiometric ratio with oxalic acid. The coprecipitated oxide obtained by firing this and aluminum oxide are mixed to obtain a mixed raw material. Ammonium fluoride as a flux is mixed with this and packed in a crucible.
A calcined product is obtained by partial calcining. The fired product can be ball-milled in water to be washed, separated, dried, and finally passed through a sieve to form a YAG-based phosphor.

Similarly, another specific phosphor used in the present invention is a nitrogen-containing CaO-Al ₂ O ₃ -SiO ₂ phosphor activated with Eu and / or Cr. This E
Nitrogen-containing CaO-Al ₂ O activated with u and / or Cr
_{The 3-} SiO ₂ phosphor is a powder obtained by mixing a raw material such as aluminum oxide, yttrium oxide, silicon nitride and calcium oxide with a rare earth raw material at a predetermined ratio under a nitrogen atmosphere.
Melt and mold at 300 ° C to 1900 ° C (more preferably 1500 ° C to 1750 ° C). The molded product can be ball-milled, washed, separated, dried, and finally passed through a sieve to form a phosphor. As a result, a Ca-Al-Si-O-N-based oxynitride fluorescence activated by Eu and / or Cr capable of emitting red light by an excitation spectrum having a peak at 450 nm and a blue light having a peak at about 650 nm. It can be glass.

C activated by Eu and / or Cr
The peak of the emission spectrum can be continuously shifted from 575 nm to 690 nm by increasing or decreasing the nitrogen content of the a-Al-Si-O-N oxynitride fluorescent glass. Similarly, the excitation spectrum can be continuously shifted. Therefore, white light can be emitted by the combined light of the light from the gallium nitride-based compound semiconductor containing the light emitting layer of GaN or InGaN doped with impurities such as Mg and Zn and the light of the phosphor of about 580 nm. In particular, I can emit light of about 490 nm with high brightness.
It is also possible to obtain light emission ideally in combination with a light emitting device made of a gallium nitride-based compound semiconductor containing nGaN in the light emitting layer.

In addition, the above-mentioned Ce-activated YAG-based phosphor and Eu and / or Cr-activated nitrogen-containing Ca-
Utilizing a light-emitting element capable of emitting blue light by combining with Al-Si-O-N oxynitride fluorescent glass, light emission with extremely high color rendering including RGB (red, green, blue) components with high brightness It is also possible to form a diode. Therefore, an arbitrary intermediate color can be formed very simply by adding a desired pigment. In the present invention, all the phosphors are inorganic phosphors, and it is possible to form a light emitting diode having both high contrast and excellent mass productivity by utilizing an organic light scattering agent, SiO _2, or the like. (Translucent Mold Member) Such a fluorescent substance is contained in the translucent mold member. As a material of the translucent mold member, a material having high light resistance to light from the light emitting element and the fluorescent substance and excellent translucency is preferable. In addition, when it works as a protective film for covering the light emitting element, a certain degree of rigidity is required. As the material of the translucent mold member, specifically, epoxy resin, silicone resin, urethane resin, unsaturated polyester resin, acrylic urethane resin,
A solventless liquid translucent thermosetting resin such as a polyimide resin is preferably used. Similarly, a solvent type liquid translucent thermoplastic resin such as an acrylic resin, a polycarbonate resin or a polynorbornene resin can be used. Further, not only an organic substance but also an inorganic substance such as silicon dioxide, or a hybrid resin in which silicon dioxide formed by a sol-gel method and an acrylic resin are mixed can be preferably used. When the translucent mold member such as the convex lens member is further covered with a resin or the like, the resin described above can be selected and used in consideration of the adhesion to the convex lens member or the like.

In the present invention, the translucent mold member 9 containing the fluorescent substance is provided on the upper surface and the side surface of the element in a wafer state. By doing this in the wafer state,
After that, polishing can be performed to adjust to a preferable film thickness, and a light-emitting device having an ideal color tone can be formed.
In addition, when the translucent mold member containing the fluorescent substance is provided so as to cover the side surface of the element, the light from the side surface of the element can be color-converted and emitted, and uneven color tone can be suppressed. In addition, the light emitting diode of the present invention,
Since there is nothing necessary for electrical connection such as a wire in the translucent mold member containing the fluorescent substance, there is nothing that blocks light and the light extraction efficiency is good.

In the present invention, the upper surface of the light-transmissive mold member serving as the light emitting surface is substantially flush with the upper surface of the bump on the electrode of the light emitting element. Here, in this specification, the term “substantially the same plane” is used in a broad sense as long as the entire side surface of the bump is coated with the light-transmissive mold resin. By covering the bumps with the translucent mold member without exposing the side surfaces thereof, it is possible to prevent moisture from being absorbed from the interface between the bump and the translucent mold member. preferable. Further, the shape of the upper surface of the mold member is not particularly limited and may be curved or may have irregularities. In such a configuration, a lens effect can be obtained and good directional characteristics can be obtained. Is obtained.

In the light emitting device thus obtained, it is assumed that the upper face of the light emitting device including the upper surface of the bump 8 and the translucent mold member 9 containing the fluorescent substance is substantially parallel to the bottom surface of the light emitting device on the substrate side. Various implementations are possible, which is preferable. Furthermore, it is preferable that the light emitting device is a substantially rectangular parallelepiped, because a plurality of light emitting devices can be easily mounted densely. In particular, when using a light emitting device having both electrodes on the same surface side, by providing bumps on each of the electrodes and setting the conductive connection portions of the positive and negative electrodes at the same height from the device bottom surface side, the lead electrode, etc. When the external electrodes and the light emitting device are electrically conductive by wires, the loop shape and the approach angle of each wire can be made equal. This improves the strength of the wire and prevents the wire from breaking due to external force or the like.

Further, as shown in FIG. 5, the translucent mold member containing the fluorescent material is formed so that the upper surface of the bump provided on each electrode of the light emitting element serves as an opening to cover the periphery of the light emitting element. It may be provided on all sides. With this structure, all the light emitted from the light emitting element can be converted satisfactorily, and a light emitting device capable of uniformly emitting light can be obtained. In particular, if a translucent mold member containing a fluorescent substance is provided on the bottom surface of the substrate side, flip mounting becomes possible and the output can be improved. On the other hand, when the substrate side of the light emitting device is opposed to the mounting substrate and fixed with a die bond resin, the fluorescent substance is contained in the die bond resin to satisfactorily convert the light emitted from the substrate bottom side of the light emitting element. Can be taken out. (Reflective Film) The reflective film 11 used in the present invention suppresses the light emitted from the substrate side to the outside, improves the light extraction efficiency, and obtains better light emission. Examples of preferable materials for the reflective film include an oxide film formed of a multilayer film and various metals. It is particularly preferable to use a metal film from the viewpoint of ease of formation. Specific examples of the metal film include Ag, Al and alloys thereof having high reflectance. These metal films can be formed by a sputtering method, a vacuum vapor deposition method, or the like. In the present invention, the reflective film may be formed so as to cover at least the bottom surface of the substrate, and is preferably continuously formed so as to cover the side surface and the bottom surface of the chip.

[0058]

EXAMPLES The light emitting diodes of the examples according to the present invention will be described below. The present invention is not limited to the examples shown below. [Example 1] Insulating substrate 1 made of sapphire (C surface)
The semiconductor layers 2 and 3 and a light emitting layer (not shown) capable of emitting blue light (470 nm) are formed on the top by the MOVPE method. After the annealing, the wafer is taken out of the reaction vessel and a predetermined Si is formed on the surface of the uppermost p-type nitride semiconductor layer.
After forming an insulating film made of O ₂ or the like, a resist film having a predetermined shape is formed on the surface of the insulating film, and etching is performed from the p-type nitride semiconductor layer side with an RIE (reactive ion etching) device. The surface of the n-type nitride semiconductor layer forming the negative electrode is exposed. Next, after peeling off the insulating film with an acid, the first positive electrode 4 made of Ni / Au is formed on almost the entire surface of the p-type nitride semiconductor layer, which is the uppermost layer, and the light transmittance at a wavelength of 470 nm is 40%. And a film thickness of 200 Å so that the surface resistivity is 2Ω / □. Next, a second positive electrode 5 made of Au is formed on the first positive electrode by a lift-off method so as to have a film thickness of 0.7 μm. on the other hand,
On the surface of the n-type nitride semiconductor layer exposed by etching, a negative electrode 6 made of W / Al / W / Au is similarly formed by a lift-off method to have a film thickness of 0.8 μm to form an LED element.

Next, patterning is performed to expose only the bonding portion of each electrode and cover the entire element with SiO 2.
_The insulating protective film 7 made of 2 is formed with a film thickness of 2 μm so that the light transmittance is 90% at a wavelength of 470 nm.

In the nitride semiconductor wafer formed as described above, as shown in FIG. 3- (a), a recess for forming a fluorescent substance-containing translucent mold member is formed on the side surface of the semiconductor layer by dicing. . By performing dicing in this way, it is possible to dispose a translucent mold member containing a fluorescent substance on the side surface of the light emitting layer of the light emitting element and suppress color unevenness, which is preferable. Further, when the wafer is scribed, the pressure applied to the wafer can be reduced, and the warp and cleavage of the substrate can be suppressed. After dicing, Au, which is the material of the bumps 8, is pressed onto each bonding surface of each electrode with a bump bomber at a height of 50 μm. (First step).

On the other hand, as a fluorescent substance (Y _0.8 Gd
_0.2 ) ₃ Al ₅ O ₁₂ : Ce 80 parts by weight, epoxy resin 100 parts by weight and acid anhydride, curing accelerator and SiO ₂ as a curing accelerator and a diffusing agent are sufficiently stirred at 65 ° C., and a fluorescent substance-containing translucent light is transmitted. A material to be the elastic mold member 9 is formed. The viscosity of the epoxy resin at this time is 700 cp. The material for the translucent mold member containing the fluorescent substance thus formed is formed into a film having a thickness of 1 so as to cover the bumps by dipping.
Coat with 50 μm (second step). 85 ℃ 1
It is cured by primary curing for 80 minutes and secondary curing at 140 ° C. for 240 minutes.

Next, the bumps 8 and the translucent mold member 9 containing the fluorescent substance are both polished from the semiconductor layer side so that the upper surface of the translucent mold member from the light emitting surface of the light emitting element is 40 μm. The surface of 8 is exposed (3rd process). Further, the substrate is ground and polished from the substrate side so that the thickness becomes 120 μm.

Finally, the translucent mold member at the position where the nitride semiconductor wafer is to be cut is removed by dicing, and then a scribe line is pulled by a scriber to cut it into chips of 300 μm square by an external force (fourth step). .

When a white LED lamp is formed using the light emitting diode formed as described above, the yield is 95%. Thus, by using the light emitting diode of the present invention, it is possible to produce a light emitting device with good mass productivity,
A light-emitting device with high reliability and less unevenness in color tone can be provided. (Comparative Example 1) On the other hand, after providing an insulating film, the nitride semiconductor layer semiconductor wafer is cut into chips, and individual light emitting elements are arranged on the bottom surface of the mount lead cup and electrically connected by wires. After that, a light-emitting diode is formed in the same manner as in Example 1 except that a transparent substance containing a fluorescent substance is first filled in the cup so as to cover the light-emitting element and then a light-transmitting convex lens member is provided. Is 85%. Further, in comparison with the light emitting diode of Example 1, uneven color tone is seen. (Example 2) Same as Example 1 except that after the fourth step, the fifth step of forming the reflection film 11 on the sapphire substrate side by the sputtering method using the sheet expand 10 for each light emitting diode is performed. When the light emitting diode is formed by using the same method, the same effect as that of the first embodiment is obtained. In addition, the light from the end face can be satisfactorily taken out to the light emitting surface, and a high output light emitting diode can be obtained. (Example 3) After the fourth step, each light emitting diode was
When a light emitting diode is formed in the same manner as in Example 1 except that a translucent mold member containing a fluorescent substance is formed from the substrate side to the periphery of the substrate, the entire periphery except the exposed surface of the bump provided on the light emitting element is provided on the outer periphery. A light emitting device having the translucent mold member containing the fluorescent substance is obtained, the same effect as in Example 1 is obtained, and the light emitted from all sides of the light emitting element can be satisfactorily converted in color. Further, color unevenness is suppressed and more uniform light emission can be obtained.

On the other hand, as a fluorescent substance (Y _0.8 Gd
_0.2 ) ₃ Al ₅ O ₁₂ : Ce (80 parts by weight), silanol (Si (OEt) ₃ OH) 100 parts by weight, and ethanol at a weight twice that of the silanol are mixed to form a slurry. Is discharged from the nozzle onto the wafer to apply it to the material of the translucent mold member containing the fluorescent substance, and then heated at 300 ° C. for 3 hours to convert silanol into SiO _2.
When the light emitting device is formed in the same manner as in Example 1 except that the fluorescent substance is fixed on the wafer, the same effects as in Example 1 can be obtained.

[0066]

As described in detail, in the light emitting device according to the present invention, before cutting the wafer into chips, bumps are formed on each electrode to raise the conductive portion, and the fluorescent substance-containing translucent light is transmitted. By providing the conductive mold member on the semiconductor layer side, a color conversion type light emitting device having high reliability and excellent optical characteristics can be efficiently produced.

In addition, the light emitting device of the present invention can have a light-transmissive mold member containing a fluorescent substance over the entire periphery of the light emitting element with the bump exposed surface as an opening, so that the light from the light emitting element is converted into the fluorescent substance. Therefore, it is possible to efficiently perform conversion, and it is possible to uniformly emit a desired color tone. Therefore, external deterioration due to light from the light emitting element can be suppressed.

Further, by providing a continuous insulating reflection film on the substrate side, a light emitting device having good light extraction efficiency and less uneven light emission can be obtained.

[Brief description of drawings]

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

FIG. 2 is a schematic plan view of a light emitting diode according to another embodiment of the present invention.

FIG. 3 is a method for forming a light emitting diode according to an embodiment of the present invention.

FIG. 4 is a step of a method for forming a light emitting diode according to another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a light emitting diode according to another embodiment of the present invention.

[Explanation of symbols] 1 ... Substrate 2 ... N-type nitride semiconductor layer 3 ... p-type nitride semiconductor layer 4 ... 1st positive electrode 5 ... Second positive electrode 6 ... Negative electrode 7 ... Insulating film 8 ... Bump 9 ... Translucent mold member containing fluorescent substance 10-Sheet Expand 11 ... Reflective film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 11/64 CQD C09K 11/64 CQD 11/80 CPM 11/80 CPM F term (reference) 4H001 CA05 XA07 XA08 XA13 XA14 XA20 XA39 YA24 YA58 YA63 4M109 AA01 BA07 EB18 EC11 EE12 GA01 5F041 AA03 AA11 AA43 CA12 CA40 CA46 CA65 CA74 CA76 CA77 CA92 CB36 DA01 DA06 DA44 DA56 EE23 FAFF 5F061 AA01 BA07 CA10 FA10

Claims (8)

[Claims] 1. A light emitting device having a semiconductor layer on a substrate,
A fluorescent substance capable of absorbing a part of light from the light emitting element and emitting light of a longer wavelength than that, and a translucent mold member having the fluorescent substance and surrounding the surface of the light emitting element. A light emitting device, comprising: at least one bump on an electrode of the light emitting element, the upper surface of the bump being substantially flush with the upper surface of the translucent mold member. 2. The film thickness of the bump is 5 μm to 150 μm
The light emitting device according to claim 1. 3. The light emitting device according to claim 1, wherein an upper surface of the light emitting device, which is composed of an upper surface of the bump and an upper surface of the translucent mold member, is parallel to a bottom surface on the substrate side. 4. The yttrium-aluminum-garnet-based fluorescent material activated by Ce, Eu is the fluorescent material.
And / or nitrogen-containing been activated with Cr _CaO-Al 2 O
The light emitting device according to claim 1, wherein the light emitting device is one selected from a _3- SiO ₂ fluorescent substance. 5. The light emitting device according to claim 1, further comprising a continuous reflective film on at least the substrate side of the light emitting element. 6. A light emitting device having a semiconductor layer on a substrate,
A fluorescent substance capable of absorbing a part of light from the light emitting element and emitting light of a longer wavelength than that, and a translucent mold member having the fluorescent substance and surrounding the surface of the light emitting element. A method of forming a light emitting device, comprising: a first step of forming a bump on an electrode of the light emitting element in a wafer state; and the translucent mold member so as to cover the bump on a semiconductor layer side of the light emitting element. A second step of coating a material to be the third step, and a third step of exposing the upper surface of the bump from the semiconductor layer side in parallel with the wafer bottom surface by polishing
And a fourth step of cutting the wafer by dicing and scribing the wafer. 7. The method for forming a light emitting device according to claim 6, wherein after the fourth step, a continuous light-transmissive mold member is formed on at least the substrate side of the light emitting element. 8. The method for forming a light emitting device according to claim 6, wherein after the fourth step, a continuous reflective film is formed on at least the substrate side of the light emitting element.