JPH07169994A - Method of manufacturing light emitting diode - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for manufacturing a light emitting diode, in which a lens having a good shape can be formed on a wafer before chip division, and which is excellent in mass productivity. [Structure] An n-type semiconductor layer 12 is formed on an n-type semiconductor substrate 10.
And a p-type semiconductor layer 14, a semiconductor multi-layer structure that emits light is formed in the light-emitting layer 13 in the vicinity of the junction, and a heavy flint glass layer 30 is formed on the p-type semiconductor layer 14.
The glass layer 30 is agglomerated by heating 0 to 400 ° C., which is equal to or higher than the deformation point, to form the glass layer 30 in a lens portion having a substantially spherical surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a light emitting diode for display and communication.

[0002]

2. Description of the Related Art A typical light emitting diode (LED) emits divergent light from a chip that constitutes the light emitting diode.

By molding the chip with a resin, the light emitted from the chip can have directivity according to the shape of the resin mold. In addition, the resin molding improves the light extraction efficiency from the chip by 2 compared with the case where the resin molding is not performed.
It can be improved up to 4 times.

However, the above resin mold has a drawback that the directivity of the light emitted from the chip cannot be precisely controlled and the light emitted from the chip cannot be made into a precise parallel light beam or a condensed light beam.

Therefore, when a light beam whose directivity is precisely controlled is required, for example, when the light of an LED is coupled to an optical fiber, the LED having a limited light emitting region is used.
The lens is precisely aligned and used. Also,
By combining a visible light LED with limited light emitting points with a lens, it is possible to configure a pointer that illuminates a specific point brightly.

Further, since the chip is resin-molded to increase its size, there is a drawback that the miniaturization of the device including the light emitting diode is restricted. For example, L
In the ED display, the resin mold is an obstacle to high definition.

Therefore, for example, in an LED printer, the resin mold is removed and the chip is directly mounted on the printed circuit board at the expense of the light extraction efficiency.

By the way, it is possible to solve the problems of difficulty in making the precision of the light directivity of the resin mold and the problem of size increase due to the resin mold by forming a lens shape in the LED itself. In addition, if a lens shape is formed in the LED itself, a higher external light extraction efficiency than that obtained by resin molding can be obtained. Therefore, some proposals have been made for making this lens shape.

FIG. 5 shows one of the examples of the above-mentioned lens shape that has been conventionally proposed. In this light emitting diode, the emission surface of the substrate 1 has a dome shape, and
The light emitting region (light emitting layer 3) is limited to a region facing the center of the dome-shaped emission surface. Therefore, the light emitting layer 3
Since the light from is incident on the emission surface almost perpendicularly, the light can be effectively extracted to the outside.

The above light emitting diode is manufactured as follows. First, on the p-type AlGaAs substrate 1 (see FIG.
Then, under the substrate 1), p-type AlGaAs layer 2 and n-type A
The lGaAs light emitting layer 3 and the n ⁺ -type GaAs cap layer 4 are sequentially formed. Then, Zn is diffused into the peripheral portion Q to make the n-type AlGaAs light emitting layer 3 and the n ⁺ -type GaAs cap layer 4 into p ⁺ layers 3Q and 4Q whose conductivity type is changed to p ⁺ type. Further, the groove 5 is formed between the peripheral portion Q and the central portion P, and the groove 5 is covered with the SiO ₂ film 6.
Next, the electrodes 7 and 8 are provided on the surfaces of the central portion P and the peripheral portion Q. The wafer formed as described above is divided into a plurality of chips, and a p-type AlG is formed for each chip.
The surface of the aAs substrate 1 is polished into a dome shape.

The above manufacturing method is disclosed in JP-A-57-19208.
Publication No. 8 and the Journal of IEEE, Quantum Electronics QE-13 Vol. 7, No. 7, pages 525-5
It is described on page 31.

[0012]

However, in the conventional example, since the dome shape is manufactured by polishing the chips one by one after dividing the chips, there is a problem that the mass productivity is poor and it is not practical.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a light emitting diode, which is capable of forming a lens having a good shape on a wafer before being divided into chips and is excellent in mass productivity.

[0014]

In order to achieve the above object, the present invention according to claim 1 provides at least a first conductive type semiconductor layer and a second conductive type semiconductor on a first conductive type semiconductor substrate. Layers are sequentially stacked to form a semiconductor multilayer structure that emits light in the vicinity of the junction between the first conductive type semiconductor layer and the second conductive type semiconductor layer, and the light emitting layer is formed on the second conductive type semiconductor layer. An aggregation layer transparent to the emission wavelength is formed, and the aggregation layer is heated to a temperature equal to or higher than the sag point of the aggregation layer to aggregate the aggregation layer, so that the aggregation layer has a substantially spherical surface shape. It is characterized in that it is formed in a lens shape.

The invention described in claim 2 is the same as claim 1.
In the method for manufacturing a light-emitting diode described in the item 1, the heating temperature of the aggregation layer is set to a temperature equal to or higher than the sag point of the agglomeration layer and equal to or lower than a temperature higher by 300 ° C. than the sag point.

The invention described in claim 3 is the same as claim 1
In the method for manufacturing a light-emitting diode according to claim 1, after forming the aggregation layer, after separating the aggregation layer into a plurality of portions, heating the aggregation layer, for each separated portion of the aggregation layer, aggregation It is characterized in that the separated portions of the layers are aggregated to form each of the separated portions into a lens portion having a substantially spherical surface.

The invention according to claim 4 is the same as claim 1.
In the method for producing a light-emitting diode according to the item 1, a guide groove for separating the aggregation region of the aggregation layer and adjusting the aggregation shape is formed in the second conductivity type semiconductor layer, and the aggregation layer is formed in the guide groove. The aggregated layer is aggregated by heating the aggregated layer to a temperature equal to or higher than the sag point of the aggregated layer to form the aggregated layer on the lens portion having a substantially spherical surface. .

The invention described in claim 5 is the same as claim 1.
The method for manufacturing a light-emitting diode according to the item 2,
On the conductive type semiconductor layer, a guide layer having a penetrating portion for separating the agglomerated region of the agglomerated layer and adjusting the agglomerated shape is formed, and the agglomerated layer is formed in the penetrating portion of the guide layer, and the agglomerate is formed. The layer is heated to a temperature equal to or higher than the sag point of the aggregation layer to aggregate the aggregation layer to form the aggregation layer in the lens portion having a substantially spherical surface shape.

The invention according to claim 6 is the same as claim 1.
In the method for manufacturing a light-emitting diode described in (3), the aggregation layer is formed on the second conductivity type semiconductor layer by a thin film forming method.

The invention according to claim 7 provides the invention according to claim 6.
In the method for manufacturing a light-emitting diode described in (3), the thin film forming method is a sputtering method.

The invention described in claim 8 is the same as claim 1.
In the method for manufacturing a light-emitting diode described in (3), the aggregation layer is formed on the second conductive type semiconductor layer by a bonding method.

The invention according to claim 9 is the method for manufacturing a light-emitting diode according to claim 8, wherein the aggregation layer is heated to bond the aggregation layer to the semiconductor multilayer structure. .

The invention described in claim 10 is the method for manufacturing a light-emitting diode according to claim 1, wherein the aggregation layer contains lead glass.

The eleventh aspect of the invention is characterized in that, in the method for manufacturing a light emitting diode according to the tenth aspect, the aggregation layer is a heavy flint glass containing lead glass and silica glass.

[0025]

According to the method of manufacturing a light emitting diode of the invention described in claim 1, an aggregation layer transparent to an emission wavelength is formed on the second conductivity type semiconductor layer, and the aggregation layer is heated. ,
The aggregation layer is melted or softened and aggregated by the surface tension so that the surface has a good spherical shape. Therefore, according to the first aspect of the present invention, a good lens portion can be manufactured on the wafer including the semiconductor layer and the aggregation layer before being divided into chips.

According to the second aspect of the present invention, the heating temperature of the agglomerated layer is set to 300 ° C. or more higher than the sag point at which the thermal expansion of the agglomerated layer becomes zero due to softening. The underlying semiconductor layer is not adversely affected by the heat treatment.

According to the third aspect of the present invention, the agglomerate layer is divided into a plurality of parts and then the agglomerate layer is heated to form the agglomerate layer into a lens shape. It can be built by heat treatment.

Further, according to the invention of claim 4, the aggregated region of the aggregated layer which is heated and softened is separated by the guide groove and the aggregated shape is adjusted, so that the lens portion can be easily formed.

According to the fifth aspect of the present invention, the guide layer separates the agglomerated regions and adjusts the agglomerated shape of the agglomerated layer heated and softened, so that the lens portion can be easily formed.

Further, according to the invention of claim 6, since the aggregation layer is formed by a thin film forming method, a uniform lens portion can be easily formed.

Further, according to the invention of claim 7, since the agglomeration layer is formed by the sputtering method, the agglomeration film has excellent adhesion and mass productivity.

Further, according to the invention of claim 8, the aggregation layer is formed by a bonding method.

Further, according to the invention of claim 9, since the aggregation layer is bonded to the semiconductor multilayer structure by heating, the adhesion property and mass productivity of the aggregation film are excellent.

According to the tenth aspect of the invention, the aggregation layer contains lead glass. Therefore, the aggregation layer has a low yield point and can be easily softened, and the aggregation layer has a high refractive index to improve the light extraction efficiency.

According to the eleventh aspect of the invention, since the aggregation layer is a heavy flint glass containing lead glass and silica glass, the aggregation layer has a particularly high refractive index and a low yield point.

[0036]

The light emitting diode of the present invention will be described in detail below with reference to examples.

[0037] In _{Examples, (Al y Ga 1-y} )
_0.5 In _0.5 P is abbreviated as AlGaInP, and Al _0.5 In
_0.5 P is abbreviated as AlInP, and Ga _0.5 In _0.5 P is Ga
Abbreviated as InP and Al _x Ga _1-x As is abbreviated as AlGaAs.

[First Embodiment] FIGS. 1A to 1D show a manufacturing process of a first embodiment of a method for manufacturing a light emitting diode according to the present invention. The light emitting diode manufactured in the first embodiment is a parallel beam emitting type AlGaInP-based LED having a large number of dome-shaped lenses and emitting high-luminance visible light. The upper surface of this AlGaInP LED is shown in FIG.
FIG. 1D shows a cross section taken along the line AA of FIG. 1 (A), (B), and (C) show cross sections at the intermediate manufacturing stage of the LED, respectively.

The first embodiment will be described with reference to FIGS. 1A to 1D in order.

First, as shown in FIG. 1A, n-type GaA
On the s substrate 10, an n-type GaInP intermediate bandgap layer 11 and an n-type AlGaInP (y = 0.7) clad layer 1 are formed.
2 and undoped AlGaInP (y = 0.5) light emitting layer 1
3, a p-type AlGaInP (y = 0.7) first cladding layer 14, and an n-type AlGaInP (y = 0.7) current blocking layer 1
5, the p-type AlGaInP (y = 0.7) second cladding layer 16, and the p-type GaAs contact layer 17 are sequentially formed on the entire surface. Then, a part of the p-type GaAs contact layer 17 is circularly etched to a depth half the layer thickness to form a circular groove 17a. This circular groove 17a is called a guide groove 17a. Next, p-type GaAs in the guide groove 17a
A Zn layer 18 is formed on the contact layer 17 and patterned.

Next, as shown in FIG. 1B, Zn diffusion is performed on the n-type AlGaInP (y = 0.7) current blocking layer 15 under the Zn layer 18 by heat treatment. By this Zn diffusion,
The conductivity type of the n-type AlGaInP (y = 0.7) current blocking layer 15 under the Zn layer 18 is reversed to the p-type, and the current path 15a is formed.
To provide. Furthermore, the Zn diffusion portion, that is, the region facing the current path 15a and the p-type GaAs contact layer 1 in the vicinity thereof
7 is removed and a light outlet 17b is provided.

Next, a heavy flint glass layer 3 having a thickness of 10 μm is formed on the entire surface by a thin film forming method such as a sputtering method.
Form 0. The heavy flint glass layer 30 is a glass layer containing lead glass and silica glass as main components and having a refractive index of 1.95. Then, as shown in FIG. 1C, the heavy flint glass layer 30 is etched with a hydrofluoric acid-based etchant so that the heavy flint glass layer 30 is formed in each guide groove 17a.
Pattern so that it remains inside.

Next, the substrate 10 and the layer 11 formed thereon
To the entire wafer 30, ie, the entire wafer, at 400 ° C., which is higher than the yield point of the heavy flint glass layer 30, 315 ° C.
It is left for 1 hour in the atmosphere, and then gradually cooled. By this heat treatment, the glass constituting the heavy flint glass 30 is aggregated, and the surface 31 of the heavy flint glass layer 30 becomes a good spherical surface as shown in FIG. 1D, and the heavy flint glass layer 30 has a spherical surface. It becomes the lens 32. When the above heat treatment is performed, the edge of the bottom surface of the aggregated heavy flint glass layer 30 is blocked by the edge of the circular guide groove 17a to prevent the protrusion from the guide groove 17a. That is, the bottom surface of the aggregated heavy flint glass layer 30 is disposed inside the circular guide groove 17a. In this way, since the guide groove 17a adjusts the aggregated shape of the flint glass layer 30, the spherical lens 32 can be easily formed.

Thereafter, the wafer subjected to the heat treatment is taken out from the heat treatment chamber, and the surface electrode 19 is attached to the taken-out wafer.
And the back surface electrode 20 is formed. Then, finally, the wafer is divided into chips.

As described above, according to the first embodiment, the spherical lens 32 can be formed in the wafer before being divided into the chips by heat-treating the heavy flint glass layer 30. Therefore, according to this first embodiment,
Since it is not necessary to form a lens for each chip after chip division, mass productivity can be greatly improved as compared with the conventional example.

The light emitting diode manufactured according to the first embodiment includes a spherical lens 32. Therefore, this light emitting diode has a high efficiency of extracting light to the outside without resin molding. However, resin molding may be performed as necessary for improving reliability or handling.

The light emitting color of the light emitting diode is green. The agglomerated heavy flint glass layer 30 of the light emitting diode is used as a spherical lens 32, and the light generated in the light emitting layer 13 in the area facing the current passage 15a can be converted into parallel rays by the lens 32. Therefore, the light emitting diode can form a pointer without using a separate lens.

The first embodiment may be modified as follows.

As the aggregating layer which agglomerates by heat treatment into a lens, various glasses other than heavy flint glass can be applied. For example, PbO-B ₂ O ₃ -Zn
O-based glass, may be employed, such as PbO-B ₂ O ₃ -SiO ₂ based glass. In the above glass, the larger the proportion of lead oxide (PbO), the higher the refractive index and the lower yield point. However, if the lead oxide content is too high, devitrification, high expansion coefficient, etc. are adversely affected. Therefore, the lead oxide content must be set within an appropriate range. As the additive to the glass forming the aggregation layer, tantalum oxide, niobium oxide, or the like may be used in addition to lead oxide.

Further, in the first embodiment, in order to aggregate the heavy flint glass layer 30, the heat treatment is performed at the ambient temperature of 4.
Although the temperature is set to 00 ° C. for 1 hour, the temperature may be set to 315 ° C. which is a temperature around the yield point. In this case, it is necessary to extend the heating time to 1 hour or more. When the temperature of the heat treatment is in the range of the temperature of the sag point of the cohesive layer to be a lens or higher and 300 ° C. higher than the temperature of the sag point, the lens moldability is good, and the lens The agglomerating layer does not extend over the guide groove, and the semiconductor layer forming the wafer is not adversely affected by heat due to high temperature. On the other hand, if the heating temperature exceeds 300 ° C. higher than the yield point, the semiconductor layer is thermally adversely affected. That is, when the temperature of the heat treatment is within the range of the temperature of the sag point of the agglomeration layer to be a lens or higher and 300 ° C. higher than the temperature of the sag point, the agglomeration layer has a good spherical shape. Not only can it be used as a lens, but also good light emission can be obtained.

In the first embodiment, the guide groove 17a is provided in order to adjust the aggregated shape of the heavy flint glass layer 30 as the aggregated layer. However, the aggregated shape is not necessarily provided even if the guide groove 17a is provided. Can be Further, as shown in the next second embodiment, a guide layer which replaces the guide groove may be used.

Further, in the first embodiment, the spherical lens 32 is arranged so that the light emitted from the light emitting region (the light emitting layer 13 in the region facing the current passage 15a) is emitted as the parallel light from the spherical lens 32. The shape (radius of curvature) of was set. The shape of the spherical lens 32 can be set by setting the thickness of the heavy flint glass layer 30 and the diameter of the guide groove 17a. Therefore, the heavy flint glass layer 3
It is also possible to change the shape of the spherical lens by changing the setting of the thickness of 0 and the diameter of the guide groove 17a so that the divergent light beam is emitted from the spherical lens.

In the first embodiment, the current blocking layer 1 is used.
5 is provided to limit the light emitting area to a narrow area facing the current passage 15a, the light emitting area is not necessarily limited. When the light emitting region is not limited, the manufacturing process of the light emitting diode can be greatly simplified.

Further, in the first embodiment, the surface electrode 19
Although AuZn was used as the above, other p-side ohmic electrodes may be used. Although AuGe is used as the back surface electrode 20 in the first embodiment, other n-side ohmic electrodes may be used.

The surface electrode 19 does not have to cover the entire exposed portion of the p-type GaAs contact layer 17. For example, the surface electrode 19 may be provided only on the wide exposed portion (wire bond pad) of the contact layer 17 existing in the center of the wafer surface shown in FIG. Further, in the first embodiment, the conductivity type of the substrate 10 is n-type, but the conductivity type of the substrate 10 is n-type.
Type or p-type may be used. When the conductivity type of the substrate 10 is n-type, the current blocking layer 15 is p-type. Therefore, the optimum thickness of the current blocking layer 15 is larger than that when the current blocking layer 15 is n-type. Become.

Further, in the first embodiment, each of the semiconductor layers 11 to 11 is
17 was formed by MOCVD method (metal organic chemical vapor deposition method), but MBE method (molecular beam epitaxy method) or VPE method was used.
It may be formed by (vapor phase growth method) or LPE method (liquid phase growth method).

In the first embodiment, the reflective layer was not provided on the substrate 10, but p-type AlInP was formed on the substrate 10.
And a p-type AlGaInP (y> 0.5) alternating multilayer film or p-type AlAs and p-type AlGaAs (x
You may provide the reflective layer which consists of an alternating multilayer film of> 0.6). If the above-mentioned reflective layer is provided, the light traveling toward the substrate can be reflected by this reflective layer and can be effectively extracted from the upper surface.

In the first embodiment, AlGaInP is used as the LED material, but the LED material is AlG
The material is not limited to aInP, and a III-V group compound semiconductor such as AlGaAs, GaAsP, GaP, AlGaN, or InGaAsP may be used instead of AlGaInP. Also, instead of AlGaInP, ZnCdSSe or ZnCdSeTe
A II-VI group compound semiconductor may be used. In addition, AlGa
CuAlSSe or CuGaSS instead of InP
A chalcopyrite semiconductor such as e may be used. Further, in the above embodiment, the material of the substrate 10 is Ga.
Although As is used, the substrate material is not limited to GaAs, and may be GaP, InP, sapphire, or the like, and may be opaque or transparent with respect to the emission wavelength.

Second Embodiment Next, FIG. 3 shows a second embodiment of the method for manufacturing a light emitting diode of the present invention. Also, FIG.
The cross section of the light emitting diode manufactured by the manufacturing method of the second embodiment is shown in FIG. This light emitting diode is an InP-based optical communication L
It is ED.

The second embodiment will be described with reference to FIGS. 4 and 3.

First, on the n-type InP substrate 210 shown in FIG. 4, an n-type InP clad layer 212 and an undoped InGaAsP (bandgap wavelength λ _g = 1.48 μm) are provided in this order.
The active layer 214, the p-type InP clad layer 216, and the p-type InP layer 218 are formed by MOCVD. Then, the p-type InP layer 218 is etched to form the substrate 210.
An opening 219 is formed at the center of the LED chip formed by the layers 212, 214, 216 and 218. After that, the n-type InP layer 220 is formed on the upper surface of the chip by MOCVD.

Next, the p-side electrode 24 is formed on the growth surface of the chip.
1 is formed, and the n-side electrode 243 is further formed on the substrate surface of the chip.
Are formed into the LED wafer 200.
The p-side electrode 241 is formed in a pattern having a circular center. The p-side electrode 241 also serves as a guide layer for adjusting the shape of the aggregation layer 250 formed in the subsequent step.

Next, the LED wafer 200 in this state is
As shown in FIG. 3A, heavy flint glass 250 having a thickness of 100 μm is superposed. Then, the first heat treatment is performed for 30 minutes at a temperature higher than the yield point of the heavy flint glass 250 by 10 ° C. Thereby, the LED wafer 200 and the heavy flint glass 250 can be bonded.

Next, as shown in FIG. 3 (B), the glass 25
Half-dicing is performed from the upper surface of 0 to the groove 2 cut to the center of the thickness direction of the InP substrate 210 shown in FIG.
55 is formed.

Next, a second heat treatment is performed from the yield point to 1
Perform at 50 ° C. higher temperature for 1 hour. As a result, the glass 250 is aggregated, and the glass 250 becomes a lens 251 that covers the entire surface of the portion of the LED wafer 200 that will be the LED chip, as shown in FIG. 3C.

According to this second embodiment, L
The lens 251 can be accurately aligned and formed on the LED chip without mounting the lens by aligning each lens for each ED chip. Therefore, the second embodiment can manufacture a light emitting diode which is excellent in mass productivity and can be optically coupled to a single mode optical fiber having a very small core diameter with extremely high efficiency.

Further, in the second embodiment, the p-side electrode 24
1 was formed into a circular penetrating pattern and served also as a guide layer so that the p-side electrode 241 limits the aggregation position of the heavy flint glass 250, which is the aggregation layer. Therefore, according to the second embodiment, the shape of the lens 251 formed from the heavy flint glass 250 can be easily controlled.

In the second embodiment, the p-side electrode 241 is used.
Although it also serves as a guide layer, a guide layer may be formed on the p-side electrode 241 separately from the p-side electrode 241. The material of the guide layer may be any as long as it has a property of repelling the aggregation layer. However, the material of the guide layer is
Metal that constitutes the p-side electrode 241 of the second embodiment
(For example, Au, Al, Cr, Ti, etc.) is convenient because the guide layer can also serve as an electrode. Examples of the material of the guide layer include nitrides such as silicon nitride and aluminum nitride, oxides such as alumina and titanium oxide, and silicon, GaAs, AlGaAs and In.
A semiconductor such as P or GaP may be used.

[0069]

As is clear from the above, the method for manufacturing a light emitting diode according to the present invention is a semiconductor multi-layer structure in which light is emitted in the vicinity of the junction between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer. By forming an aggregation layer transparent to the emission wavelength of the emitted light on the second conductivity type semiconductor layer, by heating the aggregation layer to a temperature not lower than the yield point of the aggregation layer, The aggregating layer is agglomerated to form the aggregating layer on the lens portion having a substantially spherical surface.

Therefore, according to the method of manufacturing a light-emitting diode of the invention described in claim 1, a good lens portion can be formed in the wafer including the semiconductor multilayer structure and the aggregation layer before dividing into chips. it can. Therefore, according to the present invention, it is not necessary to form a lens for each chip after dividing the chip, so that mass productivity can be greatly improved.

Further, according to the invention of claim 2, the heating temperature of the agglomerated layer is set to 300 ° C. or more higher than the sag point at which the thermal expansion of the agglomerated layer becomes zero due to softening. The underlying semiconductor multi-layer structure is not adversely affected by the heat treatment.

According to the third aspect of the present invention, the agglomeration layer is divided into a plurality of parts, and then the agglomeration layer is heated to form the agglomeration layer into a lens shape. It can be manufactured by heat treatment, and has excellent mass productivity.

Further, according to the invention of claim 4, the aggregated region of the aggregated layer which is heated and softened is separated by the guide groove and the aggregated shape is adjusted, so that the shape of the lens portion can be easily controlled. .

According to the fifth aspect of the present invention, since the aggregation layer of the above-mentioned heated and softened aggregation layer is separated by the guide layer and the aggregation shape is adjusted, the shape of the lens portion can be easily controlled. .

Further, according to the invention of claim 6, since the aggregation layer can be formed by a thin film forming method, a uniform lens portion can be easily formed.

Further, according to the invention of claim 7, since the aggregation layer can be formed by the sputtering method, the adhesion of the aggregation film and the mass productivity are excellent.

Further, according to the invention of claim 8, since the above-mentioned aggregation layer can be formed by a bonding method, it is suitable for forming a thick aggregation layer.

According to the ninth aspect of the invention, since the aggregation layer can be attached to the semiconductor multilayer structure by heating, the adhesion of the aggregation film and the mass productivity are excellent.

According to the tenth aspect of the invention, since the aggregation layer contains lead glass, the aggregation layer has a low yield point. Therefore, it is possible to easily form the lens portion at a relatively low temperature without adversely affecting the semiconductor multilayer structure with heat and to make the formed lens portion have a high refractive index, so that the light extraction efficiency is improved. You can

According to the eleventh aspect of the invention, since the aggregation layer is a heavy flint glass containing lead glass and silica glass, the aggregation layer can be made to have a particularly low sag point to facilitate the formation of the lens portion. In addition, the formed lens portion can have a particularly high refractive index, and the light extraction efficiency can be improved.

As described above, according to the present invention, by utilizing the cohesiveness of the cohesive layer due to the surface tension, L
Many good dome shaped lenses can be built into the surface of the ED wafer. Therefore, according to the present invention, it is possible to produce a light ray having a precise directivity from a small chip which is not resin-molded, and which has an excellent light extraction efficiency to the outside and an excellent light converging property.

Therefore, the present invention is effective for miniaturization and high performance of various LEDs, and is particularly effective for miniaturization and high performance of visible light LEDs and communication LEDs.
It greatly contributes to miniaturization and high performance of display light sources and printer light sources using a large number of LEDs.

[Brief description of drawings]

FIG. 1 is a first method of manufacturing a light emitting diode according to the present invention.
It is sectional drawing in each process of the AlGaInP type | system | group LED manufacturing method of an Example.

FIG. 2 is a sectional view of the completed LED.

FIG. 3 is a top view of the LED.

FIG. 4 is a cross-sectional view in each step of the InP-based LED manufacturing method of the second embodiment of the present invention.

FIG. 5 is a sectional view of the completed LED.

FIG. 6 is a cross-sectional view of a conventional LED.

[Explanation of symbols]

10 n-type GaAs substrate 11 n-type GaInP intermediate bandgap layer 12 n-type AlGaInP (y = 0.7) clad layer 13 undoped AlGaInP (y = 0.5) light-emitting layer 14 p-type AlGaInP (y = 0.7) First clad layer 15 ... n-type AlGaInP (y = 0.7) current blocking layer 16 ... p-type AlGaInP (y = 0.7) second clad layer 17 ... p-type GaAs contact layer 18 ... Zn layer 19 ... Front electrode 20 ... Back electrode 30 ... Heavy flint glass aggregation layer 32 ... Lens part 200 ... LED wafer 210 ... n-type InP substrate 212 ... n-type InP clad layer 214 ... undoped InGaAsP active layer 216 ... p-type InP clad layer 218 ... p-type InP layer 219 ... opening 220 ... n-type InP layer 241 ... p-side electrode 243 ... n-side electrode 250 ... Heavy flint glass 255 ... Groove

Claims (11)

[Claims] 1. A semiconductor substrate of the first conductivity type, at least a first conductivity type semiconductor layer and a second conductivity type semiconductor layer are laminated in this order, and the first conductivity type semiconductor layer and the second conductivity type. A semiconductor multilayer structure that emits light is formed in the vicinity of the junction of the semiconductor layers, an aggregation layer transparent to the emission wavelength of the emission is formed on the second conductivity type semiconductor layer, and the aggregation layer is the aggregation layer. A method for manufacturing a light-emitting diode, comprising: aggregating the aggregating layer by heating at a temperature equal to or higher than the deformation point of the agglomerate to form the aggregating layer on a lens portion having a substantially spherical surface shape. 2. The method for manufacturing a light-emitting diode according to claim 1, wherein the heating temperature of the aggregation layer is equal to or higher than the sag point of the agglomeration layer and equal to or lower than a temperature higher by 300 ° C. than the sag point. A method for manufacturing a light-emitting diode, comprising: 3. The method for manufacturing a light-emitting diode according to claim 1, wherein after forming the aggregation layer, the aggregation layer is separated into a plurality of parts, and then the aggregation layer is heated to obtain the aggregation layer. The method for manufacturing a light-emitting diode, wherein the separated portions of the aggregation layer are aggregated for each separated portion, and each separated portion is formed into a lens portion having a substantially spherical surface shape. 4. The method of manufacturing a light emitting diode according to claim 1, wherein the second conductivity type semiconductor layer is formed with a guide groove for separating an aggregation region of the aggregation layer and adjusting an aggregation shape, Is formed in the guide groove, the aggregation layer is heated to a temperature equal to or higher than the sag point of the aggregation layer to aggregate the aggregation layer, and the aggregation layer has a substantially spherical lens surface. A method for manufacturing a light-emitting diode, comprising: 5. The method for manufacturing a light-emitting diode according to claim 1, wherein the second conductive type semiconductor layer has a guide layer having a penetrating portion for separating an aggregation region of the aggregation layer and adjusting an aggregation shape on the second conductivity type semiconductor layer. To form the aggregation layer in the penetrating portion of the guide layer, the aggregation layer is heated to a temperature not lower than the sag point of the aggregation layer to aggregate the aggregation layer, thereby forming the aggregation layer. Is formed on a lens portion having a substantially spherical surface shape, and a method for manufacturing a light emitting diode. 6. The method for manufacturing a light emitting diode according to claim 1, wherein the aggregation layer is formed on the second conductive type semiconductor layer by a thin film forming method. 7. The method for manufacturing a light emitting diode according to claim 6, wherein the thin film forming method is a sputtering method. 8. The method for manufacturing a light emitting diode according to claim 1, wherein the aggregation layer is formed on the second conductive type semiconductor layer by a bonding method. 9. The method for manufacturing a light-emitting diode according to claim 8, wherein the aggregation layer is bonded to the semiconductor multilayer structure by heating the aggregation layer. 10. The method for manufacturing a light emitting diode according to claim 1, wherein the aggregation layer contains lead glass. 11. The method for manufacturing a light emitting diode according to claim 10, wherein the aggregation layer is heavy flint glass containing lead glass and silica glass.