JP2011035318A - Method of manufacturing light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a light emitting element capable of forming an electrode excelling in wire bondability. <P>SOLUTION: In this method of manufacturing a light emitting element, a layer containing at least AuBe as an ohmic electrode material, a Ti layer and a Au layer are formed on a surface of a p-type semiconductor crystal of a semiconductor crystal wherein at least an n-type semiconductor crystal, a luminescent layer and the p-type semiconductor crystal containing Ga or In and having a carrier concentration of 1×10<SP>17</SP>to 1×10<SP>19</SP>/cm<SP>3</SP>are formed in this order, thereafter an ohmic electrode is formed by performing a heat treatment, and thereafter the semiconductor crystal is diced. The method of manufacturing a light emitting element includes a process of cleaning at least a surface of the formed ohmic electrode using an iodine potassium iodide solution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a light-emitting element, and more specifically, to a method for manufacturing a light-emitting element including an electrode forming step capable of forming an electrode having excellent wire bondability characteristics.

  Conventionally, light emitting devices using compound semiconductor crystals such as GaP, GaAs, GaAsP, GaAlAs, and AlGaInP are known.

Here, an example of a conventional method for manufacturing a light emitting element will be described.
First, an AlGaInP light emitting layer and p-type GaP are epitaxially grown on an n-type GaAs substrate. Next, the n-type GaAs substrate is removed, and an n-type GaP substrate is bonded thereto.
Next, after forming an AuSi alloy layer on the back side of the n-type GaP substrate, a cathode electrode is formed by etching.
Next, an anode electrode layer is formed on the upper surface of the p-type GaP epitaxial layer by vapor deposition, and an anode electrode having a desired shape is formed by photolithography.
The anode electrode layer is composed of, for example, an AuBe layer (200 nm) as a lower layer and an Au layer as an upper layer. Here, the thickness of the anode electrode layer is usually about 1 to 2.0 μm.
Next, the wafer is diced or braked element by element to obtain a final light emitting element.

  Here, the anode electrode will be described in more detail. In light emitting devices using semiconductor crystals such as GaP, GaAs, GaAsP, GaAlAs, and AlGaInP, AuBe has been used for some time as an ohmic electrode provided on a p-type semiconductor crystal. .

For the formation of the electrode on the p-type semiconductor crystal side, a large-sized vapor deposition apparatus having an advantage in productivity is used as a metal film forming means of an electrode material in a mass production process, although adhesion is inferior to sputtering. Many.
In this case, the evaporation means is often evaporated by resistance heating or EB heating and plated (for example, see Patent Documents 1 and 2).

Moreover, as a semiconductor light emitting element, the p-type semiconductor crystal side is often the upper surface of the light emitting element for convenience of crystal growth order and light extraction efficiency.
Furthermore, in addition to forming an anode electrode having ohmic contact, a gold wire having a diameter of about 25 μm is wire-bonded at the time of assembling the LED lamp after the light emitting device chip is formed, so that the gold is relatively thick, about 1 to 2 μm. It is necessary to form a so-called bonding pad on the ohmic electrode.

By the way, as a basic method of forming an anode electrode having a bonding pad, wire bonding is often difficult when AuBe is vapor-deposited and Au is used as a bonding pad.
This is presumably because Au in the bonding pad portion on the electrode surface is altered by the diffusion of Ga and In from the semiconductor crystal and Be in the electrode.

As a countermeasure against this diffusion, a two-stage forming process is used in which an ohmic electrode is formed once and a bonding pad is formed thereon (see Patent Document 1).
In this method, AuBe is formed, photolithography, pattern etching, resist stripping, and heat treatment are performed, and Au is further formed to have a thickness of about 1 to 2 μm, and photolithography, mask alignment, pattern etching, resist stripping, and heat treatment are performed in this order. is there.

  However, this method doubles the process. In addition, there is a risk that the AuBe layer and the upper Au layer may peel off without being well alloyed due to a slight amount of dirt between them.

Therefore, a refractory metal such as Ti, Mo, or W, a layer of a metal close thereto, or a noble metal layer such as Pt may be provided between the AuBe layer and the Au pad layer (for example, Patent Document 3- 5).
In the case of this manufacturing method, Ti and Au are successively formed in a single vapor deposition on a dopant doped layer such as AuBe and AuZn, and completed in a single step of photolithography, pattern etching, resist stripping, and heat treatment. It is.

The anode electrode obtained by the method described in Patent Document 3-5 includes a barrier metal (a metal layer such as Ti), and can prevent diffusion of a metal such as Ga into gold during heat treatment to some extent. Is possible, but not enough.
In addition, due to increased bonding speed, the wire may not be welded well and may be peeled off, and wire bondability is still not sufficient.
Therefore, an electrode with better wire bondability is desired.

JP-A-61-180430 JP 09-232255 A JP 2000-2000926 A JP 2006-040997 A JP 2007-317913 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a light-emitting element capable of forming an electrode with good wire bondability.

In order to solve the above problems, in the present invention, at least an n-type semiconductor crystal, a light emitting layer, and Ga or In, and a carrier concentration is 1 × 10 ¹⁷ / cm ³ or more and 1 × 10 ¹⁹ / cm ³ or less. At least a layer containing AuBe, a Ti layer, and an Au layer are formed as ohmic electrode materials on the surface of the p-type semiconductor crystal of the semiconductor crystal formed in this order, and then heat treatment is performed. A method of manufacturing a light-emitting device in which an ohmic electrode is formed and then the semiconductor crystal is diced, and includes at least a step of cleaning the surface of the formed ohmic electrode with a potassium iodide iodide solution. A method for manufacturing a light emitting device is provided.

  In this way, by cleaning the surface of the ohmic electrode formed on the surface of the p-type semiconductor crystal by the heat treatment using a potassium iodide iodide solution, Ga, In, Impurities such as Al are removed, and wire bondability is improved. Accordingly, it is possible to manufacture a light emitting device in which an ohmic electrode having better wire bondability than the conventional one is formed.

  The iodine iodide solution is preferably an aqueous solution or an alcohol solution.

  Moreover, it is preferable that the weight ratio of iodine is 0.02 to 0.2% in the iodine iodide solution.

  Thus, when the weight ratio of iodine is 0.2% or less, the surface of the Au layer of the ohmic electrode outermost surface layer may corrode, and the surface of the Au layer may be uneven, or gold may be drowned. If the weight ratio of iodine is 0.02% or more, the etching power becomes weak, and there is no fear that the cleaning time becomes too long or impurities cannot be removed sufficiently. Therefore, the bonding strength can be improved more reliably.

  It is preferable to perform the cleaning of the ohmic electrode surface using the iodine iodide solution after the strain removal etching of the cut surface by the dicing.

  As described above, the cleaning with the iodine iodine iodide solution can be expected to have a certain effect by removing impurities diffused on the surface of the ohmic electrode (the surface of the Au layer of the electrode outermost layer) during the heat treatment. However, since wire bondability can be further improved by removing contamination in the step after the heat treatment, it is preferably performed after the strain removal etching of the cut surface by dicing immediately before the wire bonding.

  As described above, according to the present invention, a method for manufacturing a light emitting device capable of forming an electrode with good wire bondability is provided.

It is the process flowchart which showed an example of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the semiconductor crystal before electrode formation in the manufacture process of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the semiconductor crystal after p side ohmic electrode formation in the manufacture process of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the semiconductor crystal after n side ohmic electrode formation in the manufacture process of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the semiconductor crystal (light emitting element) after the dicing in the manufacturing process of the manufacturing method of the light emitting element of this invention. It is the figure which expanded the p-type semiconductor crystal and ohmic electrode vicinity of the light emitting element.

Hereinafter, the present invention will be described more specifically.
As described above, there has been a demand for a method for manufacturing a light-emitting element that can form an electrode with good wire bondability.

  Therefore, the present inventors have made extensive studies on the electrode forming method and the processing method for improving the wire bondability, and are related to the surface state and the wire bondability of the Au pad layer of the outermost surface layer of the p-side ohmic electrode. Found that there is.

  Then, after further diligent investigation on the surface treatment method of the bonding pad (Au pad) layer for improving the wire bondability, the iodine concentration of the iodine iodide solution usually used for removing the Au electrode is reduced. Then, it was found that by cleaning the surface of the Au pad layer, impurities such as Ga, In, Al and the like in the vicinity of the surface can be removed to improve wire bondability, and the present invention was completed based on this knowledge.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.
The manufacturing method of the light emitting element of this invention is demonstrated using FIGS.
FIG. 1 is a process flow diagram showing an example of a method for manufacturing a light emitting device of the present invention, FIG. 2 is a diagram showing an outline of a semiconductor crystal before electrode formation in the manufacturing process of the method for manufacturing a light emitting device of the present invention, and FIG. FIG. 4 is a diagram showing an outline of a semiconductor crystal after forming a p-side ohmic electrode in the manufacturing process of the light emitting device manufacturing method of the present invention, and FIG. 4 is after forming an n-side ohmic electrode in the manufacturing process of the light emitting device manufacturing method of the present invention FIG. 5 is a diagram showing an outline of a semiconductor crystal after dicing in the manufacturing process of the light emitting device manufacturing method of the present invention, and FIG. 6 is a diagram showing a p-type semiconductor crystal and an ohmic electrode of the light emitting device. It is the figure which expanded the vicinity.

First, as shown in FIGS. 1 and 2, a light emitting layer 12 made of, for example, AlGaInP on a n-type semiconductor crystal 11 (for example, an n-type GaAs substrate), and a carrier concentration containing Ga or In is 1 × 10 ¹⁷ to A semiconductor crystal 14 in which a 1 × 10 ¹⁹ / cm ³ p-type semiconductor crystal 13 (for example, a p-type GaP layer) is formed in this order by epitaxial growth is prepared (FIG. 1A).

  The n-type semiconductor crystal 11, the light emitting layer 12, and the p-type semiconductor crystal 13 may be manufactured by a general method. For example, a MOVPE (Metal Organic Vapor Phase Epitaxy) is formed on a single crystal substrate made of an n-type semiconductor crystal. After vapor-phase growth of the light emitting layer by the method, a p-type semiconductor crystal can be formed by the HVPE (Hydride Vapor Phase Epitaxy) method.

  In this case, in order to improve the light emission efficiency, the light emitting layer made of AlGaInP and the p-type semiconductor crystal are epitaxially grown on the n-type GaAs substrate, and then the n-type GaAs substrate is removed and the n-type GaP substrate is bonded thereto. May be.

Thereafter, as shown in FIG. 1B, the surface of the p-type GaP layer 13 can be washed with pure water after being washed with sulfuric acid / hydrogen peroxide.
Thereafter, as shown in FIGS. 1C and 6, first, an alloy material containing AuBe is vapor-deposited on the surface of the p-type GaP layer 13, and a layer 15a containing AuBe having a thickness of 0.3 μm, for example, is formed. Form. For example, the AuBe alloy material may be deposited in a resistance heating boat such as a tungsten boat.
Here, in addition to forming the layer 15a containing AuBe alone, an Au layer may be formed before and after the layer 15a.

Next, the Ti layer 15b is vacuum-deposited with a thickness of 50 to 150 nm by EB gun evaporation or the like.
By forming the Ti layer 15b in this manner, a barrier layer that suppresses diffusion of Be from the layer 15a containing Ga, Al, In, and AuBe from the p-type semiconductor crystal 13 to the Au layer formed thereon is formed. It is possible to reduce the concentration of impurities such as Ga and Be in the Au layer (Au pad layer) which is the outermost surface layer. Further, by setting the thickness to 50 to 150 nm, it is possible to achieve a thickness that can further suppress the diffusion of impurities such as Ga and Be into the Au layer, and it is not necessary to deposit for a long time, thereby shortening the manufacturing time. Can be achieved.

  Thereafter, an Au layer (Au pad layer) 15c is formed on the Ti layer 15b by vacuum deposition to a thickness of 1.5 to 2 μm. Thus, by setting the thickness of the Au layer 15c to 1.5 to 2 μm, better wire bonding characteristics can be obtained.

Thereafter, as shown in FIG. 1D, photolithography, etching, resist stripping, and the like are performed to form an electrode pattern. As a method for forming the electrode pattern, a general method can be used, and it is particularly preferable to use either a lift-off method or an etching method.
By using an etching method for forming the electrode pattern, the electrode pattern can be formed with high accuracy in a short time. Further, with the lift-off method, an electrode pattern can be formed with high accuracy, and an etching process using an acid or alkaline chemical having a large environmental load is not required.

Thereafter, as shown in FIGS. 1E and 3, by performing a heat treatment, the metal layer previously deposited and the p-type semiconductor crystal are brought into ohmic contact to form an ohmic electrode, thereby forming a p-side ohmic electrode 15. To do. Here, the heat treatment conditions can be set to 20 to 100 minutes at a temperature of 400 ° C. to 500 ° C. in an inert or low activity gas atmosphere (for example, Ar or N ₂ ).
Under such heat treatment conditions, it is possible to reliably prevent each metal layer from reacting with the heat treatment atmosphere or being deteriorated by heat, and making the ohmic contact between the metal layer and the p-type semiconductor crystal. Be can be diffused as much as possible.

  Moreover, it is desirable to measure the resistance between the p-side ohmic electrode and the p-type semiconductor crystal after the heat treatment, as shown in FIG.

Thereafter, as shown in FIG. 1G, the surface of the n-type GaAs layer 11 can be washed with pure water after washing with sulfuric acid / hydrogen peroxide. Thereafter, as shown in FIG. 1 (H), the Ni layer is formed on the back side of the n-type GaAs layer 11 (on the side opposite to the light-emitting layer 12 and the p-type GaP layer 13) at a degree of vacuum of about 1 × 10 ⁻⁶ Torr. An AuGe layer is formed thereon by a vapor deposition apparatus or the like.
Here, the formation method and composition of the layer made of the material to be the n-side ohmic electrode are not limited thereto, and may be appropriately selected according to the semiconductor element to be manufactured (n-type semiconductor crystal).

Thereafter, as shown in FIGS. 1 (I), (J), and FIG. 4, the electrode pattern is formed by performing steps such as photolithography, pattern etching, resist stripping, etc. Then, the n-side ohmic electrode 16 is formed.
As a method for forming the electrode pattern and heat treatment, general methods and conditions can be adopted.

  In addition, after the heat treatment, as shown in FIG. 1K, it is desirable to measure resistance in order to confirm whether or not the manufactured n-side ohmic electrode and the n-type semiconductor crystal are in ohmic contact.

Thereafter, as shown in FIG. 1L, a step of dicing the semiconductor crystal on which the electrodes are formed is performed.
Then, as shown in FIG. 1M, strain relief etching for removing damage due to dicing, roughening treatment for increasing the brightness, and the like can be arbitrarily performed.

Next, as shown in FIG. 1 (N), the surface of the ohmic electrode (p-side ohmic electrode 15) formed on the surface of the p-type semiconductor crystal is washed with a solution obtained by dissolving iodine in a potassium iodide solution. A light emitting device 10 as shown in FIG.
This potassium iodide iodide solution can be an aqueous solution or an alcohol solution. Moreover, the weight ratio of iodine in the iodine iodide solution can be 0.02 to 0.2%.

  If the weight ratio of iodine is 0.2% or less, the surface of the Au layer 15c as the outermost surface layer of the p-side ohmic electrode 15 may be corroded, and irregularities may be generated on the surface of the Au layer 15c or gold may be drawn. If the weight ratio of iodine is 0.02% or more, the etching power becomes weak, and there is no fear that the cleaning time becomes too long or impurities cannot be removed sufficiently. Therefore, the bonding strength can be improved more reliably.

The reason why bondability is improved when the surface of the p-side ohmic electrode 15 is washed with a potassium iodide iodide solution is considered as follows.
As described above, in the light emitting element manufacturing process, heat treatment is usually performed in two electrode forming processes. At this time, an alloy layer is formed at the interface between the semiconductor and the gold. At that time, it was confirmed by SIMS analysis or the like that diffusion occurred between the crystal and the direction and surface of the Au layer from the crystal to the surface of the bonding pad (Au layer). For example, Ga, In, Al or the like diffuses to the surface side of the Au layer that is the outermost surface layer of the electrode. As a result, Ga, In, Al, Be or the like enters the Au layer, which is a bonding pad, and the Au becomes hard, making it difficult to perform thermocompression bonding.

  It is also conceivable that these impurities penetrate to the surface of the Au layer and combine with oxygen, nitrogen and the like. Thus, instead of the low resistance ohmic contact between Au and the crystal due to the heat treatment, wire bondability is sacrificed. Therefore, by washing the surface of the p-side ohmic electrode 15 (bonding pad surface) with a potassium iodide iodide solution, impurities such as Ga, In, Al, and Be diffused on the bonding pad surface are removed, and wire bondability is improved. I think that.

  Further, as a characteristic inspection of the manufactured light emitting element, after the surface of the p-side ohmic electrode 15 was washed with a potassium iodide iodide solution as described above (or after the evaluation lamp was assembled (FIG. 1 (O))), a shear test ( By performing FIG. 1 (P)), it is desirable to inspect the quality of the light emitting element to be manufactured and to improve the yield.

  In the above example, the case where GaP is used for the p-type semiconductor crystal has been described. However, the present invention is not limited thereto, and other examples of the p-type semiconductor crystal include Ga such as GaAs, GaAsP, GaAlAs, AlGaInP, or the like. A semiconductor crystal containing In can be used.

  Further, the n-type semiconductor crystal is not limited to GaAs, and similarly, GaP, GaAsP, GaAlAs, AlGaInP, or the like can be used.

In the above, the cleaning of the p-side ohmic electrode surface using the potassium iodide iodide solution was performed after the strain removal etching of the cut surface by dicing. Of course, the iodine iodide solution in the manufacturing method of the light emitting device of the present invention The cleaning performed using is not limited to after the strain removal etching of the cut surface by dicing.
As described above, according to the present invention, the impurity diffused on the surface of the p-side ohmic electrode (the surface of the Au layer of the electrode outermost surface layer) by the heat treatment by cleaning the surface of the p-side ohmic electrode with a potassium iodide iodide solution. Can be removed, and the effect of improving wire bondability can be obtained. Therefore, the cleaning with the potassium iodide iodide solution ensures the effect of the present invention that the wire bondability is improved after the heat treatment for forming the p-side ohmic electrode as compared with the case where the cleaning is not performed. As long as it is after the heat treatment for forming the p-side ohmic electrode, it may be performed in any step.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to this.

(Example)
^On an n-type GaAs substrate having a thickness of 100 μm and a dopant concentration of 2 × 10 ¹⁸ / cm ³ , an AlGaInP light emitting layer having a thickness of several μm and a p-type GaP having a thickness of 5 μm and a dopant concentration of 3 × 10 ¹⁷ / cm ³ A semiconductor crystal composed of layers was produced.
Next, the surface of the p-type GaP layer was washed with sulfuric acid / hydrogen peroxide (sulfuric acid: hydrogen peroxide: pure water = 3: 1: 1) at 40 ° C. for 10 seconds and then with pure water.

Thereafter, an AuBe alloy material having a Be concentration of 1% is set in a tungsten boat at a vacuum degree of about 1 × 10 ⁻⁶ Torr, melted in a low vapor pressure state, and then evaporated to form a layer containing AuBe having a thickness of 60 nm. Filmed.
Thereafter, a Ti layer having a thickness of 80 nm was formed thereon by EB vapor deposition. When the Ti layer is formed, the Ti ingot is heated with an electron beam for about 10 minutes with a current that does not evaporate with the shutter closed, and is adsorbed by Ti such as moisture, oxygen, nitrogen in the Ti ingot. Ti was evaporated after degassing to release the components that would be. And Au layer was vapor-deposited 1.5 micrometers on it. This gold serves as a bonding pad for ultrasonic thermocompression bonding of the wire during wire bonding.

Next, a 120 μm square electrode pattern was formed by photolithography. In this case, an iodine-based etchant was used for etching the Au layer. Thereafter, the resist was peeled off.
Next, heat treatment was performed at 500 ° C. for 20 minutes in a nitrogen atmosphere to obtain ohmic contact. Thus, the p-side ohmic electrode (anode electrode) was completed.

Next, a back electrode was formed. First, the surface of n-type GaAs was washed with sulfuric acid / hydrogen peroxide (sulfuric acid: hydrogen peroxide solution: pure water = 3: 1: 1) at 40 ° C. for 10 seconds and then with pure water. Next, vacuum deposition was performed on the n-type GaAs surface. At a degree of vacuum of about 1 × 10 ⁻⁶ Torr, Ni was deposited to 30 nm, AuGe was deposited to 300 nm, and Au was further deposited to 200 nm.
Thereafter, photolithography, pattern etching, and resist removal were performed, and a heat treatment was performed at 430 ° C. for 30 minutes in a nitrogen atmosphere to form an n-side ohmic electrode (cathode electrode).
Thereafter, dicing was performed at a pitch of 280 μm to cut out a chip of about 250 μm square.
Thereafter, etching was performed at 60 ° C. for 6 minutes with sulfuric acid: hydrogen peroxide solution: pure water = 3: 1: 1 as distortion removal of the cut surface by dicing.

  Next, the surface of the p-side ohmic electrode was washed with a solution obtained by dissolving 0.15% by weight of iodine in an aqueous potassium iodide solution, then washed with water and dried. Here, an aqueous solution of potassium iodide was prepared by dissolving 230 g of potassium iodide in 1000 ml of pure water and dissolving 1.8 g of iodine therein.

  Thereafter, the chip was die-bonded on the TO-18 stem using a one-component resin containing a silver filler and thermally cured at 150 ° C. for 1 hour. Thereafter, an Au wire having a diameter of 25 μm was thermocompression bonded to the bonding pad with an ultrasonic bonder at a stem heating temperature of 100 ° C. This temperature is usually 200 ° C., but a little lower. Accordingly, the bonding strength is slightly reduced.

  Next, the ball portion of the Au wire thermocompression-bonded with a shear tester was pushed from the lateral direction, and the force (shear strength) when the ball portion of the Au wire was peeled off from the bonding pad was measured. The measurement was performed on 30 chips, and the average value was calculated. The measurement results are shown in Table 1 below.

(Comparative example)
In the examples, a light emitting device was prepared under the same conditions as in the examples except that the surface of the p-side ohmic electrode was not washed with an aqueous potassium iodide solution, and the shear strength of the Au wire was measured. In addition, the measurement was performed on 30 chips as in the example, and the average value was calculated. The measurement results are shown in Table 1 below.

  Table 1 shows that the shear strength of the light-emitting element of the example is improved as compared with the comparative example, and a stable electrode can be formed by washing with a potassium iodide iodide solution.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same function and effect. Are included in the technical scope.

  DESCRIPTION OF SYMBOLS 10 ... Light emitting element, 11 ... n-type GaAs substrate (n-type semiconductor crystal), 12 ... Light emitting layer, 13 ... p-type GaP layer (p-type semiconductor crystal), 14 ... Semiconductor crystal, 15 ... P-side ohmic electrode, 15a ... A layer containing AuBe, 15b ... Ti layer, 15c ... Au layer (Au pad layer), 16 ... n-side ohmic electrode.

Claims (4)

At least an n-type semiconductor crystal, a light emitting layer, and a p-type semiconductor crystal containing Ga or In and having a carrier concentration of 1 × 10 ¹⁷ / cm ³ or more and 1 × 10 ¹⁹ / cm ³ or less are formed in this order. At least a layer containing AuBe, a Ti layer, and an Au layer are formed as an ohmic electrode material on the surface of the p-type semiconductor crystal of the obtained semiconductor crystal, followed by heat treatment to form an ohmic electrode, and then the semiconductor crystal is formed. A method of manufacturing a light emitting device for dicing,
The manufacturing method of the light emitting element characterized by including the process of wash | cleaning at least the surface of the said ohmic electrode formed using the potassium iodide iodide solution.   The method for manufacturing a light-emitting element according to claim 1, wherein the iodine iodide solution is an aqueous solution or an alcohol solution.   3. The method for manufacturing a light-emitting element according to claim 1, wherein the potassium iodide solution has an iodine weight ratio of 0.02 to 0.2%.   The light emission according to any one of claims 1 to 3, wherein the cleaning of the ohmic electrode surface performed using the iodine iodide solution is performed after the strain removal etching of the cut surface by the dicing. Device manufacturing method.

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