JP2001210872A - Semiconductor light emitting device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a semiconductor light emitting device in which light emission characteristics of a phosphor is identical in any area of the phosphor. SOLUTION: This semiconductor light emitting device consists of a cabinet 200 of which the section is of an almost recessed shape and is provided with a hole part 220 in a recessed part 210, an LED chip 230 fit in the hole part 220, and a phosphor 260 formed on the top of the LED chip 230 and at the bottom of the recessed part 210. In the semiconductor light emitting device, the top of the LED chip 230 and the bottom of the recessed part 210 are located on almost the same plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor light emitting device and a method for manufacturing the same.

[0002]

2. Description of the Related Art One of semiconductor light emitting devices is an LED (Lig).
HT Emitting Diode) light emitting devices.

[0003] The LED light emitting devices are used in a wide range of fields as electronic devices such as personal computers and light sources such as electric bulletin boards and traffic lights in order to emit light efficiently with small size.

[0004] Recently, various technologies relating to LEDs that emit white light as well as red and blue light have been proposed.

For example, in Japanese Patent Application Laid-Open No. 11-40858, a blue-emitting LED chip is adhered to the center of a housing recess having a substantially concave cross section, and a fluorescent substance is attached to the top surface of the LED chip and the bottom surface of the recess excluding the LED chip. A technique is disclosed in which the wavelength of blue light emitted from the LED chip is converted by the fluorescent substance to emit white light.

The above-mentioned conventional light emitting device will be specifically described below.

FIG. 2 is a sectional view of the conventional LED light emitting device.

In FIG. 2, a housing 100 having a substantially concave cross section is shown.
At the center of the recess 110, an LED chip 120 is adhered with an adhesive. The LED chip 120 has an N-type conductive contact layer made of, for example, GaN, and an active layer made of non-doped InGAN on an insulating substrate. , Ga
This is a structure in which a cladding layer made of N and having P-type conductivity and a contact layer made of GaN and having P-type conductivity are sequentially laminated.

A phosphor 130 is attached to the upper surface of the LED chip 120 and the bottom surface of the housing recess 110 except for the LED chip 120, and the recess 110 is filled with resin.

When forming the light emitting device, first, the LED chip 120 is bonded to the center of the housing recess 110 with an adhesive, and the housing 100 excluding the housing recess 110 is attached.
A resist mask is formed on the upper surface. The plurality of housings 100 thus formed are put in a container, and a mixture of a phosphor and a sol made of, for example, SiO ₂ is injected into the container.

Thereafter, when the phosphor is left as it is, the phosphor 130 in the sol sinks on the upper surface of the housing 100 except for the bottom surface of the recess 110.

Next, the waste liquid in the container is removed, and the casing 100 in which the particulate phosphor has been deposited on the LED chip 120 is moved to 120.
The phosphor 130 attached to the LED chip 120 and the bottom of the housing recess 110 together with the resist mask are removed by drying with heated air, and the LED chip 12 is removed.
The phosphor 130 is formed on the upper surface and the bottom surface of the housing recess 110 excluding the LED chip 120.

Finally, the LED chip 120 and the phosphor 130
An LED light-emitting device using a phosphor is completed by pouring a transparent epoxy resin into the concave portion 110 of the housing and hardening the same to protect the device from dust and the like.

An external electrode 150 for passing a current from the outside to the p-type layer or the n-type layer of the LED chip 120 is formed below the housing 100.

[0015]

In the conventional semiconductor light emitting device, the LED chip 120 is formed so as to protrude from the center of the bottom surface of the housing recess 110. When the phosphor 130 is formed on the bottom surface of the housing recess 110, the phosphor 13 is placed in a container in which a plurality of the housings 100 are arranged.
A mixture of 0 and a sol made of, for example, SiO ₂ is injected.

Therefore, the sol is slightly convected before the phosphor 130 is deposited on the upper surface of the LED chip 120 and the bottom surface of the housing recess 110 excluding the LED chip 120, and the upper surface of the LED chip 120 protruding from the housing recess 110. The thickness of the phosphor tends to be uneven depending on the location.

Therefore, there arises a problem that the luminescent color differs depending on the location of the phosphor on the upper surface of the LED chip 120.

As a result, the wavelength of the light emitted from the semiconductor light emitting device differs depending on the position even within the same semiconductor device, and it is difficult to obtain a desired emission color.

Also, since the LED chip 120 protrudes from the housing recess 110, the distance from the active layer of the LED chip 120 to the bottom of the housing recess 110 (optical path) depends on the position of the bottom of the housing recess 110. The phosphor 130 formed on the bottom surface of the housing recess 110.
The hue of the light emitted from the light source varies.

[0020]

According to a first aspect of the present invention, there is provided a semiconductor light emitting device, comprising: an LED chip; a housing having a substantially concave concave portion on an upper surface; A phosphor that converts and emits light, wherein a hole is formed in the bottom of the recess, and the LED chip upper surface and the housing recess bottom are substantially coplanar with each other in the hole. It is characterized in that an LED chip is arranged.

According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor light emitting device, comprising: a housing having an LED chip; and a substantially concave recess having a hole for disposing the LED chip on an upper surface;
A phosphor that absorbs light sent from the LED chip and converts the wavelength of the light emitted from the LED chip, wherein the first LED chip is fitted into a hole of the housing.
And a second step of pouring a low-viscosity resin mold containing a phosphor into the recess of the housing, and placing the phosphor contained in the resin mold on the LED chip upper surface and the housing recess bottom surface. And a third step of sedimentation.

[0022]

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

In FIG. 1, a hole 220 is formed in the center of a concave portion 210 of a casing 200 made of, for example, a polycarbonate resin having a substantially concave cross section. The hole 220 is provided with, for example, an LED chip 230 for emitting blue light. The LED chip 230 is fitted into the hole 220 such that the upper surface of the LED chip 230 and the bottom surface of the concave portion 210 are on the same plane.

The LED is provided below the recess 210.
A first electrode 240 and a second electrode 250 electrically connectable to a p-type electrode and an n-type electrode formed on the chip 230, respectively;
Is arranged.

The upper surface of the LED chip 230 and the recess 2
A phosphor 260 made of, for example, an yttrium-aluminum-garnet (YAG) -based phosphor is formed on the bottom surface 10, and the recess 210 is filled with a resin 270 made of, for example, a translucent epoxy resin.

Next, the LED chip 230 shown in FIG. 1 will be specifically described below.

The LED chip 230 has a buffer layer made of, for example, GaN on a sapphire substrate, an n-type GaN cladding layer on the buffer layer, and a periodic heterostructure of InGaN / GaN on the n-type GaN cladding layer. InGaN / G with multiple quantum well (MQW) structure composed of
An aN active layer is formed on the InGaN / GaN active layer by p-type A
This is a structure in which an lGaN cladding layer is provided on the p-type AlGaN cladding layer with a p-type GaN contact layer. A p-type electrode 280 is formed on the p-type GaN contact layer via a transparent electrode, and an n-type electrode 290 is formed on a partial surface of the n-type GaN layer.

Next, a method of manufacturing the LED chip 230 of this embodiment will be described below.

First, a trimethylgallium (Ga (CH ₃ ) ₃ ) gas and an ammonia gas are flowed at a high temperature of about 600 ° C. on a sapphire substrate cleaned by organic cleaning and heat treatment, and a GaN thin film buffer is formed by MOCVD. Form a layer.

Subsequently, the substrate temperature is maintained at about 1100 degrees,
Trimethylgallium (Ga (C
H _{3) 3)} gas, ammonia gas, by flowing SiH ₄ as dopant gas, thereby forming an n-type GaN clad layer.

Thereafter, a thin film barrier layer made of GaN is formed by flowing ammonia (NH ₃ ) and trimethylgallium (Ga (CH ₃ ) ₃ ) gas.
Trimethyl gallium (Ga (CH _{3) 3)} gas, trimethyl indium (In (CH _{3) 3)} to form a quantum well layer made of In _0.35 Ga _0.65 N by pouring gas, ammonia.

At this time, the GaN barrier layer and the In
By forming five _0.35 Ga _0.65 N quantum well layers under the same conditions, an InGaN / GaN active layer having a multiple quantum well (MQW) structure composed of a periodic heterostructure of In _0.35 Ga _0.65 N and GaN is obtained. It is formed.

Next, a trimethyl gallium (Ga (CH ₃ ) ₃ ) gas, a trimethyl aluminum (Al (CH ₃ ) ₃ ) gas, ammonia,
CP ₂ Mg is poured as a dopant gas, and p-type A
An lGaN cladding layer is formed.

Thereafter, on the p-type AlGaN cladding layer, ammonia (NH ₃ ) and trimethylgallium (G
a (CH ₃ ) ₃ ) gas and Cp ₂ M as a dopant gas
g is poured to form a p-type GaN contact layer.

Subsequently, in order to form electrodes on the LED chip 230, an etching mask is formed on the p-type GaN contact layer, and the n-type GaN contact layer and the InGaN / GaN active layer which are not covered with the etching mask are formed. And part of the p-type AlGaN cladding layer and the p-type GaN contact layer are removed by reactive ion etching.

Then, the upper portion of the p-type GaN contact layer and the n-type GaN whose surface is exposed by the etching process.
A p-type electrode 280 and an n-type electrode 290 are formed on the contact layer by using a vacuum deposition method or the like.

It should be noted that the p-type GaN contact layer
The mold electrode 280 is made of, for example, an alloy of nickel and gold, and the n-type electrode 290 on the n-type GaN contact layer is made of an alloy of aluminum, silicon, nickel, gold, or the like.

Thus, the emission peak wavelength is 460 nm.
Blue light emitting LED chip 230 was formed.

Next, a method of manufacturing a white LED light emitting device in which the LED chip 230 is fitted will be described below.

First, a case 200 made of, for example, a polycarbonate resin, which can be formed by insert molding and has a substantially concave cross section, is formed, and a second portion for connecting the p-type electrode 280 to the bottom surface of the case concave portion 210 is formed. One electrode 240
And a second electrode 25 for connecting to the n-type electrode 290.
0 is formed.

Next, the LED chip 230 is bonded to the hole 220 of the housing 200 using, for example, an insulating adhesive. Thereafter, a conductive wire having a diameter of, for example, about 20 μm is attached between the p-type electrode 280 formed on the p-type GaN contact layer of the chip 230 and the first electrode 240, and the n-type formed on the n-type GaN contact layer of the chip is formed. For example, a conductive wire having a diameter of about 20 μm is attached between the electrode 290 and the second electrode 250 of the housing.

The material of the wire is Au, A
Metals or alloys such as l and Cu are used.

Subsequently, a mixture of a low-viscosity resin mold made of, for example, a translucent epoxy resin and a yttrium-aluminum-garnet (YAG) -based phosphor is poured into the recess 210 of the housing 200. Subsequently, the phosphor 260 is allowed to settle completely on the bottom surface of the concave portion 210 of the housing 200 while being left at room temperature.

Finally, the translucent epoxy resin is hardened by drying.

When the LED chip 230 of the LED light emitting device manufactured as described above emits light, the light from the LED chip 230 is wavelength-converted to yellow light by the phosphor 260 formed on the bottom surface of the concave portion 210, and the phosphor is converted to yellow light. White light was able to be obtained by mixing with the blue light transmitted through 260.

As described above, in the LED light emitting device of this embodiment, the LED chip is mounted on the housing 20 such that the bottom surface of the housing recess 210 and the upper surface of the LED chip 230 are flush with each other.
It is embedded in a hole 220 provided in the “0”. Because of this,
A phosphor 260 having the same thickness may be formed on the bottom surface of the housing recess 210 and the top surface of the LED chip 230.

Further, the phosphor 260 on the upper surface of the LED chip 230 can have a uniform thickness even in the upper surface of the chip.

As a result, it is possible to avoid the problem of the prior art, that is, the problem that the emission color differs depending on the location of the phosphor on the upper surface of the chip.

Since the light emitted from the active layer of the LED chip 230 irradiates only the periphery of the upper surface of the LED chip 230, the optical path length from the active layer of the LED chip 230 to the phosphor 260 is luminous flux. Are almost identical in all of

As a result, it is possible to avoid the problem of the prior art, that is, the problem that the emission hue differs depending on the location of the phosphor in the lateral direction of the chip.

Further, by using the method of forming a semiconductor light emitting device of this embodiment, the phosphor 260 having the same thickness can be easily formed on the bottom surface of the housing recess 210 and the upper surface of the LED chip 230.

In this embodiment, a blue light emitting LED chip having a quantum well structure as an active layer is used, but the structure of the LED chip is not limited to this.

In this embodiment, a sapphire substrate having an insulating property is used as the substrate of the LED chip 230.
By using a conductive substrate for the substrate, the LE
The p-type electrode 280 of the D chip 230 and the conductive substrate
The first electrode 240 and the second electrode 240 attached to the housing 200, respectively.
A structure for electrically connecting to the electrode 250 may be employed.

[0054]

According to the semiconductor light emitting device of the present invention, it is possible to make the light emission characteristics of the light emitted through the phosphor the same in all the regions of the phosphor that contribute to the light emission.

Further, the method for manufacturing a semiconductor light emitting device of the present invention is a simple method for making the light emission characteristics of light emitted via a phosphor the same in all regions of the phosphor contributing to light emission. It is possible to manufacture the device.

[Brief description of the drawings]

FIG. 1 is a sectional view of an apparatus according to an embodiment to which the present invention is applied.

FIG. 2 is a sectional view of a conventional semiconductor light emitting device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 housing 110 recess 120 LED chip 130 phosphor 140 resin 150 external electrode 200 housing 210 recess 220 hole 230 LED chip 240 first electrode 250 second electrode 260 phosphor 270 resin 280 p-type electrode 290 n-type electrode

Claims (2)

[Claims] 1. An LED chip, a housing having a substantially concave concave portion on an upper surface, and a phosphor disposed in the concave portion for absorbing light from the LED chip and converting the wavelength to emit light, the concave portion comprising: A semiconductor light-emitting device, wherein a hole is formed in a bottom surface, and the LED chip is disposed in the hole such that an upper surface of the LED chip and a bottom surface of the housing recess are substantially coplanar. 2. A housing having an LED chip, a substantially concave recess formed with a hole for disposing the LED chip on an upper surface, and absorbing light transmitted from the LED chip to perform wavelength conversion. A method of forming a semiconductor light emitting device, comprising: a first step of fitting the LED chip into a hole of the housing; and forming a low-viscosity resin mold containing the phosphor on the housing. A semiconductor light emitting device comprising: a second step of pouring into a concave portion; and a third step of causing a phosphor contained in the resin mold to settle on the upper surface of the LED chip and the lower surface of the concave portion of the housing. Production method.