JP2005117035A - Flip-chip gallium-nitride-based semiconductor light-emitting element and method of fabricating same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of fabricating a flip-chip gallium-nitride-based semiconductor light-emitting element having solder-coated electrodes, capable of downsizing a chip size. <P>SOLUTION: The fabrication method comprises steps of: forming a positive electrode of metal on the surface of a p-type semiconductor layer of a gallium-nitride-based semiconductor light-emitting element made up of n-type semiconductor layers and p-type semiconductor layers stacked alternately one by one on a substrate; then conferring adherence to a prescribed region of the surface of the positive electrode by reacting the prescribed region of the surface of the positive electrode and a composition containing an adherence-conferring compound; attaching solder powder exclusively on the adherence-conferred region; then heating and melting the solder power; and forming a solder layer on the prescribed region of the surface of the positive electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flip-chip type gallium nitride semiconductor light-emitting device, and more particularly to a flip-chip type gallium nitride semiconductor light-emitting device having solder-coated electrodes and a method for manufacturing the same.

  In recent years, a flip-chip type semiconductor light emitting device in which a semiconductor light emitting device electrode is directly conductively fixed on a circuit board electrode with silver paste or solder does not require the use of a wire in order to achieve conduction, and is a relatively simple process. Since a relatively small semiconductor light emitting element can be mounted, it is attracting attention (for example, Patent Documents 1 and 2). A method of forming a solder electrode on such a small semiconductor light emitting element has also been proposed (for example, Patent Document 3).

  However, recently, the demand for downsizing of the semiconductor light emitting device has been further increased, and the distance between the positive electrode and the negative electrode has become very small. When the electrode interval is reduced, a short circuit due to a solder bridge is likely to occur, and a small flip-chip type semiconductor light emitting element capable of stably preventing this short circuit is desired. This tendency is particularly strong in gallium nitride based semiconductor light emitting devices.

Japanese Patent Laid-Open No. 11-220168 Japanese Patent Laid-Open No. 2002-151739 JP-A-9-27498

  An object of the present invention is to provide a manufacturing method that enables a reduction in chip size in a flip chip type gallium nitride semiconductor light emitting device having solder-coated electrodes. Another object of the present invention is to provide excellent ohmic contact characteristics with respect to the p-type gallium nitride based semiconductor layer, and to coat a predetermined portion of the surface with solder. To provide a flip-chip gallium nitride based semiconductor light emitting device having a positive electrode with a possible structure. Another object of the present invention is to provide a small flip chip type gallium nitride based semiconductor light emitting device having a side of 280 μm or less.

The present invention provides the following inventions.
(1) A positive electrode made of metal is formed on the surface of a p-type semiconductor layer of a gallium nitride based semiconductor light-emitting device in which an n-type semiconductor layer and a p-type semiconductor layer are sequentially stacked on a substrate, and then a predetermined surface on the surface of the positive electrode is formed. By reacting the part with a composition containing a tackifying compound, the predetermined part of the surface of the positive electrode is given tackiness, and the solder powder is attached only to the tackifying part and then heated to solder powder. And a solder layer is formed on a predetermined portion of the surface of the positive electrode. A method for manufacturing a flip-chip gallium nitride semiconductor light emitting device, comprising:

(2) a first electrode layer in which the positive electrode is in electrical contact with the p-type semiconductor layer of the gallium nitride based semiconductor light emitting device and reflects light from the light emitting layer, a barrier layer for preventing diffusion of solder, and an adhesive The method for producing a flip-chip gallium nitride semiconductor light-emitting device according to (1) above, comprising a second electrode layer made of a metal that reacts with a property-imparting compound.

(3) The flip according to (2), wherein the first electrode layer is made of a metal selected from the group consisting of Au, Ag, Pt, Pd, Rh, and Al, or an alloy containing at least one of them. A method for manufacturing a chip-type gallium nitride semiconductor light-emitting device.

(4) The flip described in (2) or (3) above, wherein the barrier layer is made of a metal selected from the group consisting of Ni, Cr, Ti, W, and Mo or an alloy containing at least one of them. A method for manufacturing a chip-type gallium nitride semiconductor light-emitting device.

(5) Any one of the above (2) to (4), wherein the second electrode layer is made of a metal selected from the group consisting of Cu, Ni, Sn, and Fe or an alloy containing at least one of them. The manufacturing method of the flip chip type gallium nitride semiconductor light-emitting device according to one item.

(6) After exposing the n-type semiconductor layer to a part of the surface on the side where the positive electrode of the gallium nitride based semiconductor light-emitting element is formed and forming a negative electrode made of metal on the n-type semiconductor layer, the negative electrode After giving a predetermined portion of the surface of the negative electrode by reacting a predetermined portion of the surface and a composition containing a tackifier compound, after attaching the solder powder only to the tackified portion, The flip chip type gallium nitride system according to any one of (1) to (5) above, wherein the solder powder is melted by heating to form a solder layer on a predetermined portion of the surface of the negative electrode A method for manufacturing a semiconductor light emitting device.

(7) The method for manufacturing a flip-chip gallium nitride semiconductor light-emitting device according to (6), wherein a solder layer is simultaneously formed on the positive electrode and the negative electrode.
(8) The method for manufacturing a flip-chip gallium nitride semiconductor light-emitting element according to any one of (1) to (7) above, wherein the solder layer has a thickness of 5 to 100 μm.

(9) The method for producing a flip-chip gallium nitride semiconductor light-emitting element according to (8) above, wherein the solder layer has a thickness of 5 to 25 μm.
(10) The planar shape of the semiconductor light-emitting element is a square having a side of 200 to 280 μm, and the flip-chip gallium nitride semiconductor light-emitting element according to any one of (1) to (9) above Production method.
(11) The flip-chip type gallium nitride semiconductor light-emitting element according to any one of (1) to (10) above, wherein the interval between the solder layers of the positive electrode and the negative electrode is 30 μm to 150 μm Manufacturing method.
(12) A flip-chip gallium nitride semiconductor light-emitting element manufactured by the manufacturing method according to any one of (1) to (11) above.

(13) In the flip chip type gallium nitride semiconductor light emitting device having solder layers on the surfaces of the positive electrode and the negative electrode, the thickness of the solder layer is 5 to 100 μm, and the interval between the solder layers of the positive electrode and the negative electrode is A flip-chip type gallium nitride semiconductor light emitting device having a thickness of 30 to 150 μm and a planar shape of the device of 200 to 280 μm per side.

(14) A first electrode layer in which the positive electrode is made of a metal selected from the group of Au, Ag, Pt, Pd, Rh, and Al or an alloy containing at least one of these, Ni, Cr, Ti, W, Mo A barrier layer made of a metal selected from the group consisting of metals or an alloy containing at least one of these and a second electrode layer made of a metal selected from the group consisting of Cu, Ni, Sn, Fe or an alloy containing at least one of these The flip-chip gallium nitride semiconductor light-emitting device according to (13) above, characterized in that

(15) The flip-chip type gallium nitride semiconductor light-emitting device according to (13) or (14) is die-bonded so that the conductive circuit electrode of the circuit board and each solder layer of the light-emitting device are in contact with each other, and heating Then, the solder is melted and bonded to the circuit board, and the flip chip type gallium nitride semiconductor light emitting device mounting method is provided.

  According to the present invention, a small flip-chip type gallium nitride semiconductor light emitting device having a side length of 280 μm or less can be stably manufactured with a low defect rate such as occurrence of a short circuit. As a result, the number of light emitting element chips obtained from one wafer increases and productivity is improved. Further, as a result of downsizing of the light emitting element chip, it is possible to reduce the size of an electronic apparatus incorporating the light emitting element.

  In addition, the semiconductor light emitting device of the present invention has a high luminance and a forward voltage as a result of the positive electrode having excellent reflection characteristics with respect to light from the light emitting layer and having good ohmic contact characteristics with respect to the p-type gallium nitride semiconductor layer. A flip-chip type gallium nitride semiconductor light emitting device having a low level can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings. However, the present invention is not limited only to these drawings.
As the gallium nitride based semiconductor light emitting device used in the present invention, a conventionally known structure manufactured by a usual method can be used without any limitation. An example will be described with reference to FIG. Reference numeral 1 denotes a substrate, which is usually sapphire in a gallium nitride based semiconductor light emitting device. A buffer layer 2 made of aluminum nitride is provided thereon, and an n-type GaN layer 3 is formed thereon. A lower cladding layer 4 made of n-type GaN is formed on the n-type GaN layer 3. An active layer 5 serving as a well layer of a single quantum well structure (SQW) is formed on the lower cladding layer 4 as a light emitting layer. An upper cladding layer 6 made of p-type AlGaN is formed on the active layer 5. Further, a contact layer 7 made of p-type GaN is formed on the upper clad layer 6.

  The positive electrode is formed on the contact layer 7. The positive electrode can be formed by a conventionally known method such as vapor deposition or sputtering. Preferably, the semiconductor side has a first electrode layer made of gold (Au), silver (Ag), platinum (Pt), rhodium (Rh), palladium (Pd), aluminum (Al) or an alloy containing them, A second electrode layer made of nickel (Ni), copper (Cu), tin (Sn), iron (Fe) or an alloy thereof is formed thereon. The first electrode layer is in electrical contact with the p-type semiconductor layer, and functions as a reflective layer that efficiently reflects light from the light emitting portion of the light emitting element, and thus can efficiently extract light from the sapphire substrate side. . The second electrode layer is a material that has good wettability with solder and little solder erosion, and has a function of maintaining good bonding with the solder. In addition, the second electrode layer reacts with the composition containing the tackifier compound, thereby imparting tackiness to the surface thereof. The thickness of the first electrode layer is preferably 50 to 1000 nm. The thickness of the second electrode layer is preferably 0.1 to 2 μm, and more preferably 0.5 μm or more.

  A light-transmitting thin film electrode made of Au—Ni oxide or Au—Co oxide for reducing contact resistance may be inserted between the first electrode layer and the semiconductor layer. In this case, the first electrode layer is in electrical contact with the p-type semiconductor layer through the thin film electrode.

  Titanium (Ti), chromium (Cr), tungsten (W), molybdenum (Mo), nickel (Ni) as a solder barrier metal for preventing the diffusion of solder between the first electrode layer and the second electrode layer Or it is preferable to insert the barrier layer which consists of those alloys. However, when the second electrode layer is Ni, the barrier layer is preferably a metal other than Ni. In order to prevent solder diffusion, the thickness of the barrier layer is preferably about 100 to 1000 nm.

  The negative electrode is formed by removing the contact layer 7, the upper cladding layer 6, the active layer 5 and the lower cladding layer 4 at predetermined positions on the surface of the gallium nitride based semiconductor light emitting device, and on the exposed n-type GaN layer 3. It is formed by a known vapor deposition method or sputtering method. As the material of the negative electrode, any conventionally known material can be used, but the first electrode layer in good contact with the semiconductor is made of vanadium (V) and aluminum (Al), tungsten (W) and aluminum (Al), or As a second electrode layer for producing a solder layer on the alloy or laminated structure of titanium (Ti) and gold (Au), nickel (Ni), copper (Cu), tin (Sn), iron The structure provided with the layer which consists of (Fe) or those alloys is preferable. The thickness of the first electrode layer is preferably 50 to 1000 nm. The thickness of the second electrode layer is generally the same as that of the positive electrode. It is preferable to insert a barrier layer between the first electrode layer and the second electrode layer of the negative electrode, as in the case of the positive electrode, for preventing the diffusion of solder.

  The second electrode layers of the positive electrode and the negative electrode can each have an arbitrary planar arrangement on the first electrode layer or the barrier layer. For example, it is possible to dispose a plurality of second electrode layers on the surface of the barrier layer of the positive electrode and form a solder layer thereon. The smaller the light emitting element, the smaller the spacing between the solder layers of the positive electrode and the negative electrode, and the more likely that a short circuit (solder bridge) occurs between the two electrodes. Therefore, it is important to arrange both the positive and negative solder layers, that is, the second electrode layer in a small plane so that the distance between the positive and negative solder layers is as large as possible and the current density in the semiconductor layer is uniform. is there.

  2 to 5 are examples of electrode arrangement in the light-emitting element of the present invention. The positive electrode is formed on almost the entire surface of the contact layer excluding the portion where the negative electrode is formed in order to efficiently reflect the light from the light emitting layer to the substrate side. The negative electrode is formed with a diameter of about 50 to 150 μm in order to enable mounting on a circuit board. FIG. 2 shows an example in which positive and negative solder layers are arranged diagonally. The solder layer of the positive electrode is a right isosceles triangle having a base and a height of 50 to 150 μm. In FIG. 3, the negative electrode and its solder layer are provided at the center of the upper side, and the positive electrode solder layer is provided at a height of 20 to 100 μm along the entire lower side of the positive electrode. 4 and 5 show an example in which a plurality of positive electrode solder layers are provided, and two solder layers having a diameter of 50 to 100 μm are provided as shown in the drawing.

  By arranging the positive and negative solder layers in such a manner, it is possible to secure the interval between the positive and negative solder layers up to about 150 μm even if the light emitting element is a square having a side of 200 to 280 μm. In order to prevent the occurrence of solder bridges, the interval between the positive and negative solder layers needs to be at least 30 μm or more, preferably 50 μm or more.

  Reducing the thickness of the solder layer is also important for preventing the occurrence of solder bridges. When the solder layer is in the range of 5 to 100 μm, particularly 25 μm or less, even when the solder layer is formed on a high-definition electrode pattern, the occurrence of a short circuit (solder bridge) between the positive and negative electrodes is preferable. Desirably, it is 20 μm or less. As a result, the interval between the positive electrode and negative electrode solder layers can be made 150 μm or less. If it is too thin, contact failure with the circuit board electrode to be mounted will occur, so at least 5 μm or more, preferably 10 μm or more is required.

  As a result of the interval between the positive and negative electrode solder layers being 150 μm or less, a square semiconductor light emitting device having one side of 280 μm or less can be manufactured. However, in order to avoid a solder bridge, the length of one side of the light emitting element is preferably 200 μm or more.

  There may or may not be a protective film for protecting the surface of the semiconductor element. In the case of providing a protective film, all except the solder layer may be covered, or only the pn junction part of the semiconductor may be covered.

  There are various methods for forming the solder layer, such as a plating method, a vapor deposition method, and a dipping method. In the present invention, a predetermined part of the electrode disclosed in Patent Document 3 is given adhesiveness, and only that part is provided. A method in which solder powder is attached and heated and melted is used.

  In order to impart adhesiveness to a specific portion of the metal electrode surface, the electrode surface is treated with a compound that acts on the surface metal and develops adhesiveness. Examples of the compound include benzotriazole derivatives, naphthotriazole derivatives, imidazole derivatives, and benzimidazole derivatives that react with Cu, Ni, Sn, and Fe, which are metals constituting the second electrode layer, to exhibit adhesiveness. An aqueous solution containing a derivative, a mercaptobenzothiazole derivative, a benzothiazole thiofatty acid derivative, or the like is used. The aqueous solution is adjusted to be acidic, preferably slightly acidic with a pH of about 3 to 5, and the concentration is preferably 0.05 to 20% by mass. Furthermore, it is preferable to coexist about 100 to 1000 ppm of copper ions because the production efficiency such as the production rate and production amount of the adhesive film is increased.

  In the method for treating the metal electrode, the aqueous solution prepared as described above is brought into contact with the exposed metal portion by means of a dipping method, a coating method, a spray method or the like. Even on the metal electrode, it is preferable to cover an unnecessary portion of the solder with a resist film or the like so that the metal surface is not provided with adhesiveness. The treatment temperature is preferably in the range of room temperature to about 60 ° C. The contact time is appropriately selected within a range of about 5 seconds to 5 minutes. Next, if washing and drying with a solvent are performed as appropriate, tackiness is imparted only to the exposed metal portion. If solder powder is sprinkled and adhered to the surface of the metal electrode to which the adhesive has been imparted, and excess solder is blown off with pressurized air or removed by wet cleaning or the like, the solder powder remains only on the necessary portion of the metal electrode surface.

  The solder powder may be a commonly used eutectic solder, silver-containing solder, bismuth-containing solder, or the like. For example, Sn-Ag-Cu-based, Sn-Bi-based, Sn-Pb-based, and In-Pb-based solders can be used. The particle size of the solder powder may be appropriately selected between 5 μm and several tens of μm according to the target solder layer thickness.

  After that, solder is fixed on the electrode surface to remove a small amount of solder powder, and after applying a commercially available flux and heating to dissolve the solder, positive and negative electrodes with a solder layer only on a predetermined part of the metal electrode. An electrode is formed.

  Next, the wafer is cut and separated into individual elements by a normal dicing saw or a scribe method. The semiconductor light emitting device is die-bonded to a circuit board or a lead frame after being separated, and heated to melt and bond the solder layer for mounting.

  Hereinafter, the content of the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

  The flip chip type gallium nitride semiconductor light emitting device shown in FIG. 1 was produced. The structure of the gallium nitride semiconductor used is shown below.

The substrate 1 is made of sapphire, on which a buffer layer 2 made of aluminum gallium nitride (GaAlN) is formed with a thickness of about 200 mm, and a silicon (Si) -doped GaN film is formed thereon as an n-type GaN layer. A high carrier concentration n ⁺ layer 3 having a thickness of about 4.0 μm was formed. On this high carrier concentration n ⁺ layer 3, an n-type GaN lower cladding layer 4 made of Si-doped n-type GaN and having a thickness of about 0.5 μm was formed. Then, an active layer 5 made of GaInN having a thickness of about 50 mm corresponding to a well layer of a single quantum well structure (SQW) was formed on the lower cladding layer 4 as a light emitting layer. A p-type AlGaN upper cladding layer 6 made of p-type Al _0.15 Ga _0.85 N and having a thickness of about 600 mm was formed on the active layer 5. Further, a contact layer 7 made of p-type GaN and having a thickness of about 1500 mm was formed on the upper clad layer 6.

A method for manufacturing this gallium nitride semiconductor will be described. The gallium nitride semiconductor was manufactured by vapor phase growth by metal organic chemical vapor deposition (MOCVD method). The gases used were ammonia (NH ₃ ), carrier gas (H ₂ , N ₂ ), trimethylgallium (Ga (CH ₃ ) ₃ ) (hereinafter referred to as “TMG”), trimethylaluminum (Al (CH ₃ ) ₃ ). (Hereinafter referred to as “TMA”), trimethylindium (In (CH ₃ ) ₃ ) (hereinafter referred to as “TMI”), silane (SiH ₄ ) and cyclopentadienyl magnesium (Mg (C ₅ H ₅ ) ₂ ) ( (Hereinafter referred to as “CP2Mg”). First, the sapphire substrate 1 having the main surface of the surface a cleaned by organic cleaning and heat treatment was mounted on a susceptor and placed in a reaction chamber of an MOCVD apparatus. Next, the substrate 1 was baked at a temperature of 1150 ° C. while flowing H ₂ into the reaction chamber at normal pressure. Next, the temperature of the substrate 1 was lowered to 400 ° C., and H ₂ , NH ₃ , TMG and TMA were supplied to form the AlGaN buffer layer 2 with a thickness of about 200 mm.

Next, the temperature of the substrate 1 is raised to 1150 ° C., H ₂ , NH ₃ , TMG and silane are supplied, and the silicon (Si) -doped film having a film thickness of about 4.0 μm and an electron concentration of 2 × 10 ¹⁸ / cm ³ is supplied. A high carrier concentration n ⁺ layer 3 made of GaN was formed. Next, the temperature of the substrate 1 is kept at 1100 ° C., H ₂ , NH ₃ , TMG and silane are supplied, and the silicon (Si) doping is performed with a film thickness of about 0.5 μm and an electron concentration of 1 × 10 ¹⁸ / cm ^3. A lower clad layer 4 made of GaN was formed. After forming the lower cladding layer 4, the crystal temperature is lowered to 850 ° C., H ₂ , NH ₃ , TMG and TMI are supplied to form an active layer 5 made of Ga _0.8 In _0.2 N having a thickness of about 50 mm. Formed.

Next, the temperature of the substrate 1 is raised to 1000 ° C., and H ₂ , NH ₃ , TMG, TMA, and CP ₂ Mg are supplied, and a p-type Al _0.15 Ga _0.85 N doped with magnesium (Mg) with a film thickness of about 50 nm. An upper clad layer 6 made of Next, the temperature of the substrate 1 was maintained at 1000 ° C., and H ₂ , NH ₃ , TMG and CP2Mg were supplied to form a contact layer 7 made of p-type GaN doped with Mg and having a thickness of about 100 nm.

Next, the structure of the electrode used is shown.
A positive electrode first electrode layer 11 made of a platinum (Pt) layer was formed on the contact layer 7, and a negative electrode first electrode layer 21 was formed on the n ⁺ layer 3. The first electrode layer of the positive electrode is a platinum layer having a thickness of about 1000 mm and bonded to the contact layer 7. The first electrode layer 21 of the negative electrode has a two-layer structure of a titanium (Ti) layer having a thickness of about 200 mm and a gold (Au) layer having a thickness of about 1000 mm, and a part of the high carrier concentration n ⁺ layer 3 is exposed. It is laminated sequentially on the part.

  A barrier layer made of Cr having a thickness of 300 nm is provided on the entire surface of the first electrode layer of the positive electrode and the negative electrode to prevent the diffusion of solder.

  Further, there is a second electrode layer made of copper (Cu) for attaching solder at predetermined positions on the barrier layers of the positive electrode and the negative electrode. FIG. 6 shows the arrangement of the electrodes. The size of the light emitting element is a square having a side of 280 μm. The size of the negative electrode is a quarter circle with a radius of 100 μm. The second electrode layer and the solder layer of the positive electrode are four circular with a diameter of 40 μm, and are present on the diagonal line at equal intervals as shown in the figure. The distance between the solder layer of the negative electrode and the solder layer at the center of the positive electrode is 80 μm. The thickness of the second electrode layer is 0.6 μm for both the positive electrode and the negative electrode.

The electrode having the above configuration was formed as follows.
An etching mask is formed on the contact layer 7, the mask in a predetermined region is removed, and the contact layer 7, the upper cladding layer 6, the active layer 5, the lower cladding layer 4, and the n ⁺ layer are not covered with the mask. A part of 3 was etched by reactive ion etching with a gas containing chlorine to expose the surface of the n ⁺ layer 3.

A photoresist is applied, a window is formed in a predetermined region on the exposed surface of the n ⁺ layer 3 by photolithography, and the deposition apparatus is evacuated to vacuum, and then a titanium (Ti) layer having a thickness of about 200 mm and a thickness of about A 1000 金 gold (Au) layer was sequentially deposited. Next, the photoresist is removed. As a result, a negative electrode first electrode layer 21 was formed on the exposed surface of the n ⁺ layer 3.

  Next, a photoresist is uniformly applied on the surface, and the photoresist in the first electrode layer forming portion of the positive electrode on the contact layer 7 is removed by photolithography to form a window portion. Then, a platinum (Pt) layer having a thickness of about 1000 mm is formed on the photoresist and the exposed contact layer 7 by a sputtering apparatus, and the photoresist is removed. Thereby, the first electrode layer of the positive electrode is formed on the positive electrode forming portion on the contact layer surface.

  Next, a photoresist is uniformly applied on the surface, and the photoresist on the first electrode layer of the positive electrode and the negative electrode is removed by photolithography to form a window portion. Then, a chromium layer having a thickness of about 300 nm is formed on the photoresist and the exposed first electrode layer of the positive electrode and the negative electrode by vapor deposition. Next, the photoresist is removed. Thereby, a barrier layer made of Cr functioning as a solder barrier is formed on the exposed surface of the first electrode layer of the positive electrode and the negative electrode.

  Further, a photoresist is uniformly applied again on the surface, and the photoresist on the positive electrode and negative electrode barrier layers is removed by soldering into the shape of a solder-coated portion to form a window portion. Then, a copper (Cu) layer having a thickness of about 0.6 μm is formed on the photoresist and the exposed barrier layer by vapor deposition, and the photoresist is removed. As a result, a second electrode layer made of Cu is formed on the solder-coated portion of the barrier layer surface.

Thereafter, a protective film 30 made of SiO ₂ is uniformly formed on the uppermost layer by electron beam vapor deposition, and is exposed to an exposed portion other than the positive and negative second electrode layers by wet coating through a photoresist coating and photolithography process. A protective film 30 made of a SiO ₂ film is formed.

  Next, the wafer is immersed in a 2-dodecylimidazole (1 wt%) aqueous solution adjusted to a pH of about 4 with acetic acid at 45 ° C. for 5 minutes, then washed with water and dried, and the surface of the positive and negative second electrode layers Was given tackiness. Eutectic solder powder with an average particle size of 20 μm was sprinkled and excess solder was blown off with pressurized air. Thereafter, the solder was fixed on the electrode surface by heating at 140 ° C. for 20 minutes. A small amount of solder powder was removed with a brush, and after applying commercially available water-soluble flux, the solder powder was melted in a reflow oven at 230 ° C. for 1 minute. A fine solder layer having a thickness of about 15 μm was formed on the surface of the second electrode layer.

  The wafer was attached to an adhesive sheet and cut with a dicing saw at a pitch of 280 μm to obtain a flip chip type gallium nitride semiconductor light emitting device. After the separation, the light emitting element is die-bonded so that the conductive circuit electrode of the circuit board (printed circuit board) and each solder layer of the light emitting element are in contact with each other, and heated in a reflow furnace at 230 ° C. for 1 minute to melt the solder and circuit. Bonded to the substrate and mounted.

An energization test was performed on 200 samples. In the flip-chip type gallium nitride semiconductor light-emitting device obtained by this method, the defect rate of short circuit or disconnection was 0%.
In addition, the luminance of this light-emitting element at 20 mA energization was 5.2 mW on average and the forward voltage was 3.4 V, and a light-emitting element with high luminance and low forward voltage was obtained.

  The small flip-chip gallium nitride semiconductor light-emitting device provided by the present invention is useful as a blue light-emitting device for electronic devices such as various indicators.

It is sectional drawing of an example of the flip chip type gallium nitride semiconductor light-emitting device of this invention. It is a figure which shows an example of electrode arrangement | positioning in the light emitting element of this invention. It is a figure which shows another example of the electrode arrangement | positioning in the light emitting element of this invention. It is a figure which shows another example of the electrode arrangement | positioning in the light emitting element of this invention. It is a figure which shows another example of the electrode arrangement | positioning in the light emitting element of this invention. It is a figure which shows electrode arrangement | positioning of the flip chip type gallium nitride semiconductor light-emitting device manufactured in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sapphire substrate 2 AlN buffer layer 3 n-type GaN layer 4 n-type GaN lower cladding layer 5 active layer 6 p-type AlGaN upper cladding layer 7 p-type GaN contact layer 10 positive electrode 11 first electrode layer 12 barrier layer 13 Second electrode layer 14 Solder layer 20 Negative electrode 21 First electrode layer 22 Barrier layer 23 Second electrode layer 24 Solder layer 30 Protective film

Claims (15)

  A positive electrode made of metal is formed on the surface of a p-type semiconductor layer of a gallium nitride based semiconductor light-emitting device in which an n-type semiconductor layer and a p-type semiconductor layer are sequentially stacked on a substrate, and then adhered to a predetermined portion of the surface of the positive electrode. By reacting with a composition containing a tackifier compound, the predetermined portion of the surface of the positive electrode is imparted with tackiness, and after the solder powder is attached only to the tackifier portion, heating is performed to melt the solder powder. A method of manufacturing a flip chip type gallium nitride semiconductor light emitting device, comprising forming a solder layer on a predetermined portion of the surface of the positive electrode.   A first electrode layer in which the positive electrode is in electrical contact with the p-type semiconductor layer of the gallium nitride based semiconductor light emitting device and reflects light from the light emitting layer; a barrier layer for preventing diffusion of solder; and a tackifying compound 2. The method of manufacturing a flip chip type gallium nitride based semiconductor light emitting device according to claim 1, wherein the second electrode layer is made of a metal that reacts with the second electrode layer.   3. The flip-chip gallium nitride according to claim 2, wherein the first electrode layer is made of a metal selected from the group consisting of Au, Ag, Pt, Pd, Rh, and Al or an alloy containing at least one of these metals. For manufacturing a semiconductor light emitting device.   4. The flip-chip gallium nitride semiconductor according to claim 2, wherein the barrier layer is made of a metal selected from the group consisting of Ni, Cr, Ti, W, and Mo or an alloy containing at least one of them. Manufacturing method of light emitting element.   5. The flip according to claim 2, wherein the second electrode layer is made of a metal selected from the group consisting of Cu, Ni, Sn, and Fe or an alloy containing at least one of them. A method for manufacturing a chip-type gallium nitride semiconductor light-emitting device.   After exposing the n-type semiconductor layer to a part of the surface on the side where the positive electrode of the gallium nitride based semiconductor light-emitting element is formed, forming a negative electrode made of metal on the n-type semiconductor layer, A predetermined part and a composition containing a tackifier compound are reacted to impart adhesiveness to a predetermined part of the surface of the negative electrode, and after applying solder powder only to the tackified part, heat 6. The method of manufacturing a flip-chip gallium nitride semiconductor light emitting device according to claim 1, wherein the solder powder is melted to form a solder layer on a predetermined portion of the surface of the negative electrode. .   7. The method of manufacturing a flip chip type gallium nitride based semiconductor light emitting device according to claim 6, wherein solder layers are simultaneously formed on the positive electrode and the negative electrode.   The method for manufacturing a flip-chip gallium nitride semiconductor light-emitting element according to claim 1, wherein the solder layer has a thickness of 5 to 100 μm.   9. The method of manufacturing a flip chip type gallium nitride based semiconductor light emitting device according to claim 8, wherein the solder layer has a thickness of 5 to 25 [mu] m.   10. The method for manufacturing a flip-chip gallium nitride semiconductor light-emitting element according to claim 1, wherein the planar shape of the semiconductor light-emitting element is a square having a side of 200 to 280 μm.   The method for manufacturing a flip-chip gallium nitride based semiconductor light-emitting device according to any one of claims 1 to 10, wherein the interval between the solder layers of the positive electrode and the negative electrode is 30 to 150 µm.   A flip chip type gallium nitride semiconductor light emitting device manufactured by the manufacturing method according to claim 1.   In a flip-chip gallium nitride semiconductor light emitting device having a solder layer on the surface of the positive electrode and the negative electrode, the thickness of the solder layer is 5 to 100 μm, and the distance between the positive and negative electrode solder layers is 30 to 150 μm. A flip chip type gallium nitride based semiconductor light emitting device, wherein the planar shape of the device is 200 to 280 μm per side.   The positive electrode is a first electrode layer made of a metal selected from the group of Au, Ag, Pt, Pd, Rh, and Al or an alloy containing at least one of these, and a group of Ni, Cr, Ti, W, and Mo A barrier layer made of a selected metal or an alloy containing at least one of them and a second electrode layer made of a metal selected from the group of Cu, Ni, Sn, Fe or an alloy containing at least one of these The flip-chip type gallium nitride semiconductor light-emitting device according to claim 13.   15. The flip chip type gallium nitride based semiconductor light emitting device according to claim 13 or 14 is die-bonded so that an electrode of a conductive circuit on a circuit board and each solder layer of the light emitting device are in contact with each other, and heated to melt the solder. A method of mounting a flip-chip gallium nitride based semiconductor light-emitting device, characterized by bonding to a circuit board.

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