JP4451683B2 - Semiconductor light emitting device, manufacturing method thereof, and light emitting diode - Google Patents

Description

  The present invention relates to a semiconductor light emitting device using a transparent substrate, a manufacturing method thereof, and a light emitting diode.

  2. Description of the Related Art Conventionally, for the purpose of increasing the brightness of a semiconductor light emitting element (hereinafter simply referred to as “light emitting element”) and improving the mechanical strength, a technique for removing the opaque semiconductor substrate on which the semiconductor layers are laminated and bonding the transparent substrate is known. It has been. And the method of joining a transparent substrate to the surface of a semiconductor layer is technically difficult, and many kinds of methods are devised, for example, the following patent documents 1, 2, and 3 are known.

Japanese Patent No. 3230638 JP-A-6-302857 JP 2002-246640 A

  Patent Document 1 describes a method of directly bonding a transparent substrate to a semiconductor layer while applying pressure at a high temperature. Patent Document 2 describes a method of directly bonding using a wafer bonding method. Patent Document 3 describes a method of bonding using a transparent adhesive material such as an epoxy resin.

  Of the above Patent Documents 1 to 3, the direct bonding methods of Patent Documents 1 and 2 generally require a high temperature and high pressure of 700 ° C. or higher, and a large stress is applied to the semiconductor layer. Moreover, since it is joining of solids which do not soften, if the surface is not smooth, joining will become non-uniform | heterogenous and joining failure will occur frequently. Furthermore, bonding at high temperatures is more stable due to the occurrence of warpage due to differences in thermal expansion coefficient and stress due to mechanical stress, which often cracks or cracks during cooling, leading to deterioration in the quality of the light emitting part. Advanced technology and equipment are required for manufacturing.

  On the other hand, in the bonding method of Patent Document 3, since bonding can be performed at a low temperature, bonding failure due to stress at high temperature and surface roughness is improved. However, since a resin-based material cannot withstand high temperature, a process after bonding is performed. There is a problem of being subject to significant restrictions. For example, when forming an ohmic electrode after bonding, a heat treatment at 400 ° C. or higher is performed. However, at this time, the resin-based material changes in quality and the adhesive layer becomes opaque.

  In addition, due to the occurrence of stress in Patent Documents 1 and 2 and the alteration of the adhesive layer in Patent Document 3, peeling of the joints and cracks frequently occur in element separation processes such as dicing and scribing. For this reason, it has been difficult to achieve both an adhesion method that adheres at low temperature and low stress and satisfies heat resistance.

  The present invention has been proposed in view of the above-described problems, and has found an adhesive layer having high adhesive force and excellent heat resistance even under low temperature and low pressure bonding conditions of 700 ° C. or lower, and stress generated during bonding. An object of the present invention is to provide a high-luminance semiconductor light-emitting device that can be reduced and can be stably produced, a method for manufacturing the same, and a light-emitting diode.

To achieve the above object, the present invention provides (1) a semiconductor light emitting element, a semiconductor layer including a light emitting portion, a transparent transparent substrate to the emission wavelength of the light emitting portion, the semiconductor layer and the seen containing a low-melting point glass layer for bonding the transparent substrate, wherein the low-melting-point glass layer is the thermal expansion coefficient of 2~9 × 10 ^-6 / K, the transparent substrate is thermal expansion coefficient of 2 to 9 × 10 ^-6 / K glass .

  In addition to (2) the configuration of the invention described in (1) above, the low melting point glass layer has a softening point of 500 ° C. or more and 700 ° C. or less, and the semiconductor layer and the transparent substrate are combined. The bonding temperature at the time of joining is 500 ° C. or more and 700 ° C. or less.

Further, the present invention is characterized in that ( 3 ) in addition to the configuration of the invention described in (1) or (2) above, the low-melting glass layer does not contain lead.

The present invention (4) in addition to the structure of the invention according to the above (1) to (3), the low-melting-point glass layer is SiO _2, ZnO, and B ₂ O ₃ as a main component, characterized in that It is said.

Furthermore, the present invention is characterized in that ( 5 ) in addition to the configuration of the invention described in (1) to ( 4 ) above, the transparent substrate has a thickness of 70 μm or more and 300 μm or less.

The present invention is characterized in that ( 6 ) in addition to the configuration of the invention described in the above (1) to ( 5 ), the light emitting portion is made of AlGaInP.

Further, the present invention is characterized in that ( 7 ) in addition to the configuration of the invention described in (1) to ( 5 ) above, the light emitting portion includes a GaInN mixed crystal.

In addition to the configuration of the invention described in ( 8 ) above (1) to ( 7 ), the present invention provides the light emitting portion having a single heterostructure or a double heterostructure having a quantum well structure. It is characterized by that.

In addition to the configuration of the invention described in ( 9 ) (1) to ( 8 ), the present invention is characterized in that the semiconductor layer does not contain As.

In addition to ( 10 ) the configuration of the invention described in (1) to ( 9 ) above, the present invention provides a first ohmic electrode formed on a surface having a first polarity of the semiconductor layer, A metal reflective layer covering a surface having the first polarity and the first ohmic electrode formed on the surface; and a second ohmic electrode formed on the surface having the second polarity of the semiconductor layer. It is a feature.
In addition, the present invention provides (11) a semiconductor light emitting device, wherein a semiconductor layer including a light emitting part, a transparent substrate transparent to the light emission wavelength of the light emitting part, and a low bond between the semiconductor layer and the transparent substrate are bonded. A melting point glass layer, wherein the low melting point glass layer has a thermal expansion coefficient of 2 to 9 × 10 ⁻⁶ / K, and the transparent substrate is made of GaP.

The present invention relates to ( 12 ) a method for producing a semiconductor light emitting device, comprising a step of growing a semiconductor layer including a light emitting portion on a semiconductor substrate opaque to the light emitting wavelength, and transparent to the light emitting wavelength of the light emitting portion. in thermal expansion coefficient is formed on the surface of a transparent substrate made of glass 2~9 × 10 ^-6 / K, and the low-melting glass layer in the thermal expansion coefficient of 2~9 × 10 ^-6 / K, the semiconductor layer Bonding a low melting point glass layer having a thermal expansion coefficient of 2 to 9 × 10 ⁻⁶ / K formed on the surface of the substrate, a step of removing the opaque semiconductor substrate, and a step of removing the opaque semiconductor substrate And a step of forming an ohmic electrode in a subsequent semiconductor layer.

In addition to the structure of the invention described in ( 13 ) above ( 12 ), the present invention provides a low melting point glass layer on the surface of the transparent substrate and a low melting point glass layer on the surface of the semiconductor layer. The formation of is characterized by vacuum deposition or sputtering.

In addition to the structure of the invention described in ( 14 ) ( 12 ) or ( 13 ), the present invention is characterized in that the semiconductor layer is grown using an MOCVD method.

Furthermore, the present invention is characterized in that ( 15 ) in addition to the configuration of the invention described in ( 12 ) to ( 14 ) above, a selective etching process is included in the removal step of the semiconductor substrate.

Moreover, this invention is ( 16 ) The light emitting diode using the semiconductor light-emitting device as described in said (1) thru | or (11) .

  In the semiconductor light-emitting device, the manufacturing method thereof, and the light-emitting diode of the present invention, the semiconductor layer and the transparent substrate are bonded with a low-melting glass interposed therebetween, so that even under low-temperature and low-pressure bonding conditions of 700 ° C. or lower. It can be strongly bonded, and warpage due to stress on the semiconductor layer or difference in thermal expansion coefficient can be greatly reduced. In addition, there is no breakage or cracking during cooling.

  In addition, since an adhesive layer having excellent heat resistance can be formed, it is possible to prevent the adhesive layer from being denatured or becoming opaque even when heat treatment at 400 ° C. or higher is performed in forming an ohmic electrode after bonding.

  Therefore, almost no cracking or peeling occurs, and a high-luminance and high-quality light-emitting element can be stably produced.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  1A and 1B are diagrams schematically showing a manufacturing process of a semiconductor light emitting device according to the present invention, in which FIG. 1A shows a first-stage stacked structure and FIG. 1B shows a second-stage stacked structure. Note that (b) is shown upside down with respect to (a).

  The semiconductor light emitting device 10 of the present invention is formed through a manufacturing process as shown in FIG. That is, in the first stage shown in FIG. 1A, first, a semiconductor layer 2 including a light emitting portion 2a is grown on a semiconductor substrate 1 that is opaque to the emission wavelength, and a low melting point glass is formed on the surface of the semiconductor layer 2. Layer 3a is formed. Moreover, the low melting glass layer 3b is formed on the surface of the transparent substrate 4 that is transparent to the emission wavelength of the light emitting portion 2a. In the second stage shown in FIG. 1B, the low-melting glass layer 3a formed on the surface of the semiconductor layer 2 and the low-melting glass layer 3b formed on the surface of the transparent substrate 4 are joined and integrated. The semiconductor substrate 1 is removed from the semiconductor layer 2. In this way, the semiconductor layer 2 including the light emitting part 2a, the transparent substrate 4 transparent to the light emission wavelength of the light emitting part 2a, and the low melting point glass layer 3 (3a, 3a, 3) joining the semiconductor layer 2 and the transparent substrate 4 3b) is obtained, according to the present invention.

The low-melting-point glass forming the low-melting-point glass layer 3 is glass containing lead oxide, boron oxide, zinc oxide, silicon oxide, etc., but a material containing no lead is desirable from the viewpoint of environmental load. From the viewpoint of thermal expansion coefficient and softening point, low melting point glass mainly composed of zinc oxide, boron oxide and silicon oxide is suitable. The low-melting glass can be formed by printing, vapor deposition, sputtering, etc., but vapor deposition and sputtering are preferable because the film thickness is thin and easy to control. In particular, the sputtering method is optimal because of its good surface condition. The low-melting glass preferably has a thermal expansion coefficient in the range of 2 to 9 × 10 ⁻⁶ / K, which is close to that of the semiconductor layer 2 and the semiconductor substrate 1. If the difference in thermal expansion coefficient is large, it will cause stress and cracking on the semiconductor. The low melting point glass functions as an adhesive layer by heat treatment at a temperature near the softening point. Since there is a possibility that the luminance of the semiconductor layer 2 may be lowered, the heat treatment temperature at the time of adhesion is preferably 700 ° C. or lower, and is preferably 500 ° C. or higher in consideration of heat resistance in the subsequent process.

The thermal expansion coefficient of the transparent substrate 4 is preferably in the range of 2-9 × 10 ⁻⁶ / K, which is close to that of the semiconductor layer 2 and the semiconductor substrate 1. If the difference in thermal expansion coefficient is large, it will cause stress and cracking on the semiconductor layer 2.

  For the transparent substrate 4, a material that is transparent with respect to the emission wavelength, such as quartz, glass, sapphire, GaP, SiC, AlGaAs, GaAsP, and ZnSe, or a transparent conductive film material that is made of ITO (indium tin oxide) or the like may be selected. However, among these materials, glass and a GaP substrate that are inexpensive and easy to process are desirable.

  The thickness of the transparent substrate 4 is desirably 300 μm or less from the viewpoint of ease of processing into a chip, and is 70 μm from the viewpoint of preventing the occurrence of cracking when the transparent substrate 4 is bonded to the semiconductor layer 2 and handling the chip assembly process such as die bonding. The above thickness is desirable.

  As the semiconductor substrate 1, GaAs, InP, GaP, Si, or the like can be used. For the light emitting part 2a, a semiconductor used in a known light emitting element such as GaP, AlGaInP mixed crystal, GaAlAs mixed crystal, GaAsP mixed crystal, and GaInN mixed crystal can be used.

  As the light emitting portion 2a, a structure of a light emitting portion that is usually used, such as a single hetero structure, a double hetero structure, or a quantum well structure, can be used. Moreover, it is good also as a single hetero structure or a double hetero structure provided with the quantum well structure. In particular, the present invention has a great effect of increasing the luminance of the semiconductor light emitting device for the light emitting portion 2a made of AlGaInP using a GaAs substrate which is difficult to increase in thickness and has a normal structure in terms of lattice matching.

  In order to obtain the light emitting portion 2a having high luminance, it is desirable to select the material of the light emitting portion 2a having a lattice constant matched to the semiconductor substrate 1 and grow the semiconductor layer 2. As a growth method, a known technique such as a liquid phase growth method, MBE method, MOCVD method or the like can be used, but the MOCVD method is most preferable in terms of mass productivity and quality. In addition to the light emitting portion 2a, the semiconductor layer 2 includes a buffer layer with the semiconductor substrate 1 used in the prior art, a Bragg reflection layer, an etching stop layer for selective etching, and a contact layer that lowers the contact resistance of the ohmic electrode. In addition, a current spreading layer, a current blocking layer for controlling a current flowing region, a current constricting layer, and the like can be combined. These layers may be appropriately combined with necessary layers according to the manufacturing method, cost, and quality.

The method of performing heat treatment by superimposing the low melting point glass layer 3b on the transparent substrate 4 side and the low melting point glass layer 3a on the semiconductor layer 2 side uses known heat treatment means such as an oven, an electric furnace, an infrared lamp, a hot plate, etc. it can. When a pressure of 1 g / cm ² or more is applied so that the bonding surface does not shift during heat treatment, the bonding uniformity and adhesive strength are further improved. However, in consideration of the reduction of stress on the light emitting portion 2a, 100 g / cm ² or less is desirable. . The heat treatment is desirably performed at a temperature lower than 700 ° C. and controlling the cooling rate in order to reduce stress and suppress deterioration of the light emitting portion 2a.

  The semiconductor substrate 1 can be removed by methods such as machining, polishing, and chemical etching. In particular, in chemical etching, selective etching using the difference in etching rate depending on the material is the optimum method in terms of mass productivity, reproducibility, and uniformity.

  In order to construct a light emitting element from the above-described laminate 10, the light extraction surface is the transparent substrate 4, and the first electrode is formed on the surface of the semiconductor layer 2 having the first polarity exposed by removing the semiconductor substrate 1. In addition, a second electrode is formed on the surface of the second polarity semiconductor layer 2 exposed by removing a part of the semiconductor layer 2, and further, the first electrode and the surface of the underlying semiconductor layer 2 A metal reflective layer is provided to cover the surface. This structure is a so-called flip-chip type element structure, and the light extraction efficiency can be improved by the reflective layer. Details of the element structure will be described later.

  Other element manufacturing methods can use known light-emitting element manufacturing techniques, and manufacture light-emitting elements through ohmic electrode formation, element separation, and inspection / evaluation processes. Furthermore, a light emitting diode (lamp) can be manufactured by incorporating a light emitting element into a package.

  Next, structural examples of the semiconductor light emitting device of the present invention manufactured as Example 1 will be described in order with reference to FIGS.

  FIG. 2 is a diagram showing a layer structure of a semiconductor epitaxial wafer (laminated body) used in the semiconductor light emitting device, and FIGS. 3 and 4 are diagrams showing a configuration example of the semiconductor light emitting device of the present invention manufactured from the semiconductor epitaxial wafer of FIG. 3 is a plan view thereof, and FIG. 4 is a cross-sectional view taken along the line II of FIG. The semiconductor light emitting device 100 manufactured in Example 1 emits red light.

As shown in FIG. 2, a semiconductor epitaxial wafer 10A used for manufacturing a semiconductor light emitting device 100 is formed on a semiconductor substrate 11 made of a GaAs single crystal having a surface inclined by 15 ° from an n-type (001) surface doped with Si. Next, a buffer layer 21 made of n-type GaAs doped with Si, an etching stop layer 22 made of n-type (Al _0.5 Ga _0.5 ) _0.5 In _0.5 P doped with Si, a light emitting portion 20a, and Zn doped The semiconductor layer 20 composed of the p-type GaP layer 26 is stacked.

The light emitting portion 20a has a double hetero structure, and is composed of a Si-doped n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower cladding layer 23, undoped (Al _0.2 Ga _0.8 ) _0.5 In _0.5 P And a top clad layer 25 made of Zn-doped p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P.

When the semiconductor epitaxial wafer 10A is formed, first, the layers 21 to 26 of the semiconductor layer 20 are made of trimethylaluminum ((CH ₃ ) ₃ Al), trimethyl gallium ((CH ₃ ) ₃ Ga) and trimethyl. The indium ((CH ₃ ) ₃ In) was laminated on the semiconductor substrate 11 by a low pressure metal organic chemical vapor deposition method (MOCVD method) using a group III constituent element material. Diethyl zinc ((C ₂ H ₅ ) ₂ Zn) was used as a Zn doping raw material. Disilane (Si ₂ H ₆ ) was used as a Si doping material. Further, phosphine (PH ₃ ) or arsine (AsH ₃ ) was used as a raw material for the group V constituent elements. The lamination temperature of each of the layers 21 to 26 constituting the semiconductor layer 20 was unified to 730 ° C.

The buffer layer 21 had a carrier concentration of about 5 × 10 ¹⁸ cm ⁻³ and a layer thickness of about 0.2 μm. The etching stop layer 22 has a carrier concentration of about 2 × 10 ¹⁸ cm ⁻³ and a layer thickness of about 0.5 μm. The lower cladding layer 23 had a carrier concentration of about 8 × 10 ¹⁷ cm ⁻³ and a layer thickness of about 1 μm. The light emitting layer 24 is undoped and has a thickness of 0.5 μm. The upper cladding layer 25 had a carrier concentration of about 2 × 10 ¹⁷ cm ⁻³ and a layer thickness of 1 μm. The GaP layer 26 had a carrier concentration of about 5 × 10 ¹⁸ cm ⁻³ and a layer thickness of 7 μm.

Next, 0.3 μm of low melting point glass (softening point 650 ° C., thermal expansion coefficient 4 × 10 ⁻⁶ / K) made of ZnO, B ₂ O ₃ , SiO ₂ is formed on the surface of the semiconductor layer 20 by sputtering. The low melting point glass layer 30a was obtained.

On the other hand, a low-melting glass (softening point 650 ° C., made of ZnO, B ₂ O ₃ , SiO _{2 on} the surface of 150 μm thick borosilicate glass (thermal expansion coefficient 7 × 10 ⁻⁶ / K) to be the transparent substrate 40. A thermal expansion coefficient of 4 × 10 ⁻⁶ / K) was formed by sputtering to a thickness of 0.3 μm to form a low-melting glass layer 30b.

The semiconductor layer 20 and the transparent substrate 40 are overlapped so that the surfaces of the low-melting glass layers 30a and 30b are in contact with each other, and heat treatment is performed in a state where a load of 5 g / cm ² is applied, and both the 30a and 30b are bonded. did. The bonding temperature condition at this time was 650 ° C. for 30 minutes, and cooling to 400 ° C. was performed by slow cooling at 1 ° C./min.

  Next, the semiconductor substrate 11 and the buffer layer 21 were selectively removed with an ammonia-based etchant.

  Subsequently, an electrode or the like was formed on the semiconductor epitaxial wafer 10A configured as described above to produce the light emitting device 100 (FIGS. 3 and 4). That is, an n-type electrode 51 made of an Au / Ge alloy was formed as a first electrode on the surface of the etching stop layer 22 having an n-type polarity by a vacuum deposition method so as to have a thickness of 0.3 μm. . The n-type electrode 51 was patterned using a general photolithography means to form a triangular linear electrode having a width of about 20 μm as shown in FIG.

  On the surface of the n-type electrode 51 and the surface of the semiconductor layer 20 (etching stop layer 22), 0.05 μm of Cr and then about 1 μm of gold were laminated by sputtering to form a metal reflective layer 52. Thereafter, the semiconductor layer 20 was further removed by etching with a sulfuric acid / hydrogen peroxide-based etchant to expose the GaP layer 26 having p-type polarity to form a fan-shaped region having a radius of 150 μm.

  In order to form the second electrode on the GaP layer 26, a pattern is formed in a fan-shaped region having a radius of 130 μm. First, a gold / beryllium alloy having a thickness of 0.5 μm, and a thickness of 1 μm The gold to be deposited was deposited on the patterning resist surface by a general vacuum deposition method. Subsequently, the resist was removed by a known lift-off method to form a fan-shaped p-type electrode 53.

  Next, after the formation of the n-type electrode 51 and the p-type electrode 53, a low resistance ohmic contact between each of the electrodes 51 and 53 and the semiconductor layer 20 is performed by performing an alloying heat treatment at 480 ° C. for 15 minutes in a nitrogen stream. Formed.

  As described above, the epitaxial wafer on which the n-type electrode 51, the p-type electrode 53, and the metal reflective layer 52 were formed was cut into the shape of the element by a normal scribing method, and individually divided into the semiconductor light emitting element 100. As shown in FIG. 3, the semiconductor light emitting device 100 has a square shape with a side of 300 μm as viewed in plan, and a thickness of about 160 μm.

  Further, a light emitting diode was assembled using the semiconductor light emitting device 100.

FIG. 5 is a plan view of the light emitting diode according to the present invention, and FIG. 6 is a cross-sectional view taken along the line II-II of FIG. One light emitting element 100 is formed by forming gold ball bumps 65 on the first electrode terminal 64 and the second electrode terminal 62 formed on the substrate 63, and the p-type electrode 53 and the metal reflection layer 52 of the light emitting element 100. Were brought into contact with the ball bumps 65 and bonded by pressure bonding. Next, it was sealed with a transparent epoxy resin 61 to produce a light emitting diode (LED) 60.

  When a forward current is passed through the first electrode terminal 64 and the second electrode terminal 62 of the LED 60 manufactured as described above, the current is reflected by the metal reflection layer 52 and passes through the surface and side surfaces of the transparent substrate 40. Then, red light having a dominant wavelength of about 620 nm was emitted. The forward voltage (Vf: per 20 mA) when a current of 20 milliamperes (mA) flows in the forward direction reflects the good ohmic characteristics of the electrodes 51 and 53, and is about 2.0 volts (V). became. The light emission intensity at this time was 160 mcd super high brightness reflecting that the light emission efficiency of the light emitting part 20a was high and the efficiency of taking out to the outside was devised.

  In addition, in Example 1 described above, the LED 60 is manufactured using the n-type semiconductor substrate 11, but the effect of the present invention can be obtained even with an LED manufactured using the p-type semiconductor substrate.

  In addition, although the AlGaInP double heterostructure is used for the light emitting section 20a of the present invention, the effects of the present invention can also be obtained with a light emitting section using a known technique in terms of emission wavelength, structure, material, dopant, and the like.

  Further, in the first embodiment, a general chip-type LED 60 is shown, but the same effect can be obtained with a so-called bullet-type or display package having a different shape, or a light-emitting diode having a different emission wavelength.

In Example 1 above, a low-melting glass having a thermal expansion coefficient of 4 × 10 ⁻⁶ / K was used and the bonding temperature was 650 ° C., but in Example 2, the thermal expansion coefficient was 8 × 10 ⁻⁶ / K. The adhesion temperature was set to 500 ° C. using a low melting point glass. The other conditions were the same as in Example 1, and a light-emitting diode was fabricated. The emission intensity was measured. As a result, a high brightness of 150 mcd was obtained as in Example 1.

  (Comparative Example) Using the same process as in Examples 1 and 2 above, various light emitting devices were produced by changing the thermal expansion coefficient of the low melting point glass, the bonding temperature, and the thermal expansion coefficient of the transparent substrate. The evaluation results of Comparative Examples 1 to 6 and Examples 1 and 2 are shown in Table 1.

In Comparative Examples 1, 2, and 4, the low-melting glass has a thermal expansion coefficient exceeding 9 × 10 ⁻⁶ / K, and in Comparative Example 3, the transparent substrate has a thermal expansion coefficient of 2 × 10 ⁻⁶ / K. Since the difference between the thermal expansion coefficient of the semiconductor layer and about 5 × 10 ⁻⁶ / K is large, thermal distortion occurs, and cracks and peeling occur during the process, and the device cannot be manufactured. It was. In Comparative Example 5, the bonding temperature exceeded 700 ° C., and the heat deteriorated the quality of the semiconductor layer, resulting in low luminance.

  Comparative Example 6 shows a 300 μm-pitch semiconductor light-emitting device manufactured with a general structure using the same epitaxial wafer as in Example, in which substrate removal and glass pasting are not performed, are shown in FIGS.

  7 is a plan view of the semiconductor light emitting device fabricated in Comparative Example 6, and FIG. 8 is a view showing a cross section taken along the line III-III of FIG. The semiconductor light emitting device 90 is configured by laminating a semiconductor layer 92 and a first ohmic electrode 93 on a semiconductor substrate 91 made of GaAs and forming a second ohmic electrode 94 on the back surface of the semiconductor substrate 91. .

  In Comparative Example 6, the upper electrode 93 is connected by gold wire bonding. The first electrode 93 was formed by forming a p-type ohmic electrode made of a gold / beryllium alloy so as to have a thickness of 0.3 μm, and further using a vacuum vapor deposition method so that the thickness of gold became 1 μm. Patterning was performed using general photolithography means to form a circular first electrode 93 having a diameter of 130 μm.

  Thereafter, when a forward current was passed through the first electrode terminal and the second electrode terminal of the LED manufactured in the same manner as in the example, the wavelength was set to about 620 nm through the surface and side surfaces of the semiconductor layer 92. Red light was emitted. The forward voltage (Vf: per 20 mA) when a current of 20 mA (mA) was passed in the forward direction was about 2.0 volts (V), which was the same as in Examples 1 and 2. The emission intensity at this time was 60 mcd. The emission intensity was less than half that of Examples 1 and 2 of the present invention. This is considered to be due to the fact that the emission efficiency is reduced because the GaAs semiconductor substrate 91 absorbs light emission.

  As described above, in the present invention, the semiconductor layer and the transparent substrate are bonded with the low-melting glass interposed therebetween, so that the semiconductor layer and the transparent substrate are strongly bonded even under a low temperature and low pressure bonding condition of 700 ° C. or lower. Therefore, warpage due to stress on the semiconductor layer and a difference in thermal expansion coefficient can be significantly reduced. In addition, there is no breakage or cracking during cooling.

In addition, since an adhesive layer having excellent heat resistance can be formed, it is possible to prevent the adhesive layer from being denatured or becoming opaque even when heat treatment at 400 ° C. or higher is performed in forming an ohmic electrode after bonding.
Therefore, almost no cracking or peeling occurs, and a high-luminance and high-quality light-emitting element can be stably produced.

  In addition, since the ohmic electrode and the metal reflection layer are provided on a part of the surface of the semiconductor layer, the light from the light emitting part can be efficiently taken out to the outside, and ultra-high luminance is achieved.

  In addition, since the light emitting diode has a flip chip structure, the light emitting diode can be easily assembled, and the wire is not broken, thereby improving the reliability.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematically the manufacturing process of the semiconductor light-emitting device of this invention, (a) shows the laminated structure of the 1st step, (b) shows the laminated structure of the 2nd step. It is a figure which shows the layer structure of the semiconductor epitaxial wafer (laminated body) used for a semiconductor light-emitting device. It is a top view which shows the structural example of the semiconductor light-emitting device of this invention manufactured from the semiconductor epitaxial wafer of FIG. 4 is a cross-sectional view taken along the line II of FIG. It is a figure which shows the II sectional view of FIG. It is a top view of the light emitting diode which concerns on this invention. It is a figure which shows the II-II line cross section of FIG. 14 is a plan view of a semiconductor light emitting element of Comparative Example 6. FIG. It is a figure which shows the III-III line cross section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Semiconductor layer 2a Low melting glass layer 2a Light emission part 3 Low melting glass layer 3a Low melting glass layer 3b Low melting glass layer 4 Transparent substrate 10 Laminated body 10 Semiconductor light emitting element 10A Semiconductor epitaxial wafer 11 Semiconductor substrate 20 Semiconductor layer 20a Light emitting portion 21 Buffer layer 22 Etching stop layer 23 Lower clad layer 24 Light emitting layer 25 Upper clad layer 26 GaP layer 30a Low melting glass layer 30b Low melting glass layer 40 Transparent substrate 51 n-type electrode 52 Metal reflective layer 53 p-type electrode 60 Light emission Diode (LED)
61 Epoxy Resin 62 First Electrode Terminal 63 Substrate 64 Second Electrode Terminal 65 Ball Bump 90 Semiconductor Light Emitting Element 91 GaAs Substrate 92 Semiconductor Layer 93 First Electrode 94 Second Electrode 100 Semiconductor Light Emitting Element

Claims (16)

A semiconductor layer including a light emitting portion;
A transparent substrate transparent to the emission wavelength of the light emitting part,
And a low melting glass layer to bonding the transparent substrate and the semiconductor layer, only including,
The low-melting glass layer has a thermal expansion coefficient of 2 to 9 × 10 ⁻⁶ / K,
The transparent substrate is made of glass having a thermal expansion coefficient of 2 to 9 × 10 ⁻⁶ / K.
A semiconductor light emitting element characterized by the above.   2. The semiconductor according to claim 1, wherein the low melting point glass layer has a softening point of 500 ° C. or more and 700 ° C. or less, and an adhesion temperature when the semiconductor layer and the transparent substrate are joined is 500 ° C. or more and 700 ° C. or less. Light emitting element.   The semiconductor light emitting element according to claim 1, wherein the low-melting glass layer does not contain lead. 4. The semiconductor light-emitting element according to claim 1, wherein the low-melting glass layer contains SiO ₂ , ZnO, and B ₂ O ₃ as main components.   5. The semiconductor light emitting element according to claim 1, wherein the transparent substrate has a thickness of 70 μm or more and 300 μm or less.   The semiconductor light emitting element according to claim 1, wherein the light emitting portion is made of AlGaInP.   The semiconductor light-emitting element according to claim 1, wherein the light-emitting portion includes a GaInN mixed crystal.   8. The semiconductor light emitting element according to claim 1, wherein the light emitting portion has a single heterostructure or a double heterostructure having a quantum well structure. 9.   The semiconductor light emitting element according to claim 1, wherein the semiconductor layer does not contain As. A first ohmic electrode formed on a surface having a first polarity of the semiconductor layer;
A metal reflective layer covering the surface having the first polarity and the first ohmic electrode formed on the surface;
A second ohmic electrode formed on the surface of the semiconductor layer having the second polarity;
The semiconductor light emitting device according to claim 1, comprising: A semiconductor layer including a light emitting portion;
A transparent substrate transparent to the emission wavelength of the light emitting part,
A low melting point glass layer that joins the semiconductor layer and the transparent substrate,
The low-melting-point glass layer is the thermal expansion coefficient of 2~9 × 10 ^-6 / K,
The transparent substrate is made of GaP.
A semiconductor light emitting element characterized by the above. Growing a semiconductor layer including a light emitting portion on a semiconductor substrate opaque to the emission wavelength;
Transparent to the emission wavelength of the light emitting portion, the thermal expansion coefficient is formed on the surface of a transparent substrate made of glass 2~9 × 10 ^-6 / K, the thermal expansion coefficient of 2~9 × 10 ^-6 / K Bonding the low melting point glass layer and a low melting point glass layer having a thermal expansion coefficient of 2 to 9 × 10 ⁻⁶ / K formed on the surface of the semiconductor layer;
Removing the opaque semiconductor substrate;
Forming an ohmic electrode in the semiconductor layer after the removal step of the opaque semiconductor substrate,
A method for manufacturing a semiconductor light emitting device.   The method for producing a semiconductor light-emitting element according to claim 12, wherein the formation of the low melting point glass layer on the surface of the transparent substrate and the formation of the low melting point glass layer on the surface of the semiconductor layer are performed by vacuum deposition or sputtering. .   The method of manufacturing a semiconductor light emitting element according to claim 12, wherein the semiconductor layer is grown using an MOCVD method.   The method for manufacturing a semiconductor light emitting element according to claim 12, wherein the step of removing the semiconductor substrate includes a selective etching process.   A light-emitting diode using the semiconductor light-emitting element according to claim 1.

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