TW200832762A - Process for producing light emitting element - Google Patents

Abstract

A p-type AlGaAs light takeout layer (20) having a (100) face is subjected to surface roughening treatment by an etching liquid FEA, for surface roughening, which contains acetic acid, hydrofluoric acid, nitric acid, iodine, and water so that the total amount thereof is not less than 90% by mass and the total content (by mass) of acetic acid, hydrofluoric acid, nitric acid, and iodine is higher than the content (by mass) of water. Prior to the step of surface roughening with the etching liquid FEA for surface roughening, the first main surface (main light takeout region) of a laminate formed of AlGaAs is pretreated by bringing the first main surface into contact with a pretreating liquid formed of an aqueous hydrogen peroxide sulfate solution, whereby the occurrence of unevenly protrusion formed state of a wafer produced by the surface roughening can be effectively prevented. The above constitution can realize even surface roughening treatment of the light takeout face in the AlGaAs light emitting element and in its turn can provide a production process of a light emitting element which is less likely to cause an unevenly surface roughened state.

Description

200832762 IX. EMBODIMENT OF THE INVENTION: TECHNICAL FIELD The present invention relates to a method of manufacturing a light-emitting element. [Prior Art Patent Document 1 Patent Document 2 Patent Document 3 Patent Document 4 Patent Document 5 Patent Document 6 AlxGa Japanese Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei.

As mixed crystal (where 〇 $ x $ 1 ; below, also known as

A light-emitting element in which an AlGaAs mixed crystal or only AlGaAs is formed into a light-emitting layer portion is used as a red light-emitting element having high directivity and high luminous efficiency. In such a light-emitting element, the peripheral region of the metal electrode of the A1GaAs layer is used as the light extraction surface, but light incident on the light extraction region at an angle larger than the critical angle among the light from the inside of the element toward the light extraction region (incident) The angle of incidence of the incident beam of the horn beam and the angle of the normal of the area plane are not returned to the inside of the component due to human reflection. Therefore, the Cocoon W documents 1 to 6 disclose a technique in which surface roughening treatment is performed on the light extraction surface with an anisotropic residual liquid to form fine irregularities (also 淼 淼 、, U 』, % In the case of the frost-like surface treatment, the probability of the incident angle of the illuminating light beam is reduced, and the efficiency of the light-emitting beam is increased. 20085 200832762 [Explanation] However, the surface of the above-mentioned Patent Documents 1 to 6 is performed: When the surface of the surface is rough, the shape of the protrusion is formed (the shape of the protrusion is such that the yield of the component of the component is reduced, or the number of defective products of the appearance inspection step is removed: large: problem. In particular, when When the light extraction surface forms the surface 曰 of the i _ η joint surface, the thickness of the surface 曰 is small. If the protrusion is deeply formed, the adjacent fish argon will reach the ρ·η joint interface and the surface layer will be “faced” in (4) The current diffusion state is deteriorated, and the light extraction efficiency is lowered. The object of the present invention is to provide a method for producing a light-emitting device, in which the bean can be uniformly ground-finished on the light extraction surface of the A1GaAs light-emitting device. In order to solve the above problems, the method of manufacturing a light-emitting element of the present invention is characterized in that the following steps are carried out in the following order: · The light-emitting element wafer manufacturing step 'will be composed of a composition formula' The compound represented by HAS (wherein 0<χ<1)) is composed of n-type Α1 (the layer and the P-type A1GaAs layer are laminated to form a laminate by forming a p_n junction to fabricate a light-emitting element wafer; main light extraction In the region roughening step, the first main surface of the shell layer is anisotropically etched by the surfacing layer with a surname to form a surface rough protrusion; the etching liquid contains a total of 9% by mass or more. Acetic acid, hydrofluoric acid, tartaric acid, and discard water, and 7 masses ^ ^ ^ ^ and the total mass content of ethyl sulfonium, fluorinated acid, nitric acid and iodine are higher than the mass content of water. 6 200832762 According to the method of the present invention, by using the surface (4) of the unique surface of the present invention containing acetic acid, hydrogen acid, and u, even the first main surface of the laminate which is not composed of GaAs is specially subjected to the mask treatment. , Make The younger-main surface is in contact with the (iv) liquid, and can still be formed by the anisotropic surrogate: the unevenness is formed remarkably, and the surface thick-chain protrusion can be formed on the first main surface of the laminated body in an efficient and inexpensive manner. The total amount of acetic acid, hydroquinone, acid, and water is 9 G% by mass or more, and if it is 90% by mass, the surface roughness is not efficiently formed. The total mass content of fluoric acid, acid and strontium is lower than that of water 3, and the same thick layer protrusions cannot be formed efficiently. In addition, acetic acid, hydrofluoric acid, and stone xiao are deducted from 1 〇 0% by mass. The remainder of the total of acid and spotted water may be added to other components (such as carboxylic acid other than acetic acid) without affecting the anisotropy of the 胄 ( (4): fruit.

Further, the use of the surface roughening effect (anisotropic effect) is the above-described light-emitting element wafer. The protrusion shape of the money engraving liquid to AlGaAs is particularly remarkable for the (100) plane of AlGaAs, and it is preferable that the main surface is made of (1 〇〇) _ after the surface roughening step by the etching liquid for surface roughening, The first main surface (the main light extraction region) of the laminate formed of AlGaAs can be pre-processed by contacting the previous treatment liquid composed of the sulfuric acid-hydrogen peroxide aqueous solution. Thereby, the rough surface rf can be effectively prevented. The result of the formation of the Japanese dog is not uniform. As a result, the formation of deep local protrusions can be suppressed, and the A1GaAs layer on the light extraction surface side is less likely to be produced due to the deep protrusion. In the case of the product yield, the "removal of the wafer from the wafer to remove the sputum" can also greatly save the labor time of the appearance inspection step. The effect of the type A1GaAs layer and the p-type αι extraction side are formed to be 10 hearts to be located in the pupil, and the T shape of the T ^ v is particularly remarkable for charging "also performing in-plane current diffusion, which is better than # m") Also μ 1

The surface roughening etching liquid 'specifically' is preferably used in the following range: Bucin consumption acetic acid (calculated as CH3C00H): 37. 4 mass% or more and 94.8 mass denier % or less; Hydrofluoric acid (in terms of HF): 〇·4 mass% or more Μ·8 mass% or less; nitric acid (calculated as ΗΝ〇3): υ% by mass or more and 14.7% by mass or less; iodine (in terms of 12): 〇 - 12% by mass or more 〇 84% by mass or less; and the water content is 2.4% by mass or more and 45% by mass or less. When any of the components is outside the range of the above composition, the anisotropic etching effect on the surface of the AlGaAs single crystal is insufficient, and the surface rough protrusion cannot be sufficiently formed on the first main surface of the laminate. The etching liquid for surface roughening is more preferably used in the following range: · acetic acid (in terms of CH3COOH): 45.8 mass ❹ / 〇 or more and 94.8 mass % β; hydrofluoric acid (in terms of HF) · · 〇 · 5 mass% 14.8 mass% or less; nitric acid (calculated as HN〇3)·· 1.6 mass% or more and 14_7% by mass or less; broken (to change the nose)·〇”5 mass 1% or more 〇·84 mass% or less; 8 200832762 and water The content is 2.4% by mass or more and 32.7% by mass or less. That is, in order to improve the anisotropic etching effect on the (1 Å) plane of the A1 GaAs single crystal, it is particularly important to maintain the water content in a small amount as described above, and to use acetic acid as the main acid solvent without using water. The function. Pretreatment liquid, 96% sulfuric acid can be used in a mixing ratio of 5: 1: 1 or more 20: 1 : 30% hydrogen peroxide water: water: 1 or less. When sulfuric acid ratio

When the rate is less than 5:1: i, the unevenness suppression effect by the pre-treatment protrusion is insufficient. If it exceeds 15: 丨: 丨, the protective photoresist for etching is decomposed, and the electrode pattern is liable to be defective. When the protective photoresist is not used, as long as it is 1: 1 or less, a sufficient unevenness suppressing effect of the protrusion formation can be obtained. [Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Fig. 1 is a conceptual view showing a light-emitting element 1A according to an embodiment of the present invention. The light-emitting element 1A is formed of P-type AlxGai-xAs (where 00<x<:2 layer 2〇 (hereinafter referred to as p-type AlGaAs layer 2〇)) which forms a light extraction surface (first main surface), and Forming an n-type AlxGa]-xAs (where 〇<x<1) layer 90 (hereinafter, referred to as an n-type AlGaAs layer 90) of the main surface (second main surface) on the opposite side thereof to form a p_η joint The laminated layer is formed by a laminated body. The thickness of the p-type AlGaAs layer 20 is lem or more and 1 μm or less (for example, 6/zm), and the thickness of the n-type A1GaAs layer 9 is 15 〇# m or more and 200 Å or less (for example, 170). #m) The p-type A1GaAs layer 2〇 and the n-type AlGaAs layer 90 are all described below, and are grown on an n-type GaAs single crystal substrate (the main surface is a (100) plane) by n-type AlGaAs 9 200832762 The layer 90 side is formed by the sequential heterogeneous growth of the crystal. The P-type AlGaAs layer 20 is in the form of a part of the main surface (the (100) plane) (here, the central part). In the old small form, the region side metal electrode 9 is taken out first. On the light extraction region side, the metal electrode 9 is bonded to one end of the electrode wire. On the light extraction region side, the metal electrode #9 In the surrounding area, the main light extraction region 2〇P is formed. Further, the side surface of the laminate formed by the dicing (that is, the side surface of the p-type A1 GaAs layer 20 and the n-type A1 GaAs layer 9 )) forms a side light extraction region 20S. On the other hand, the n-type Al GaAs layer 9 〇, the inner surface of the second main surface, the entire surface of the u Au electrode, etc., is covered by the electric surface 15 and is distributed between the inner surface electrode 15 and the „type full_layer 9G. A bonding alloying layer 15c made of an AuGeNi alloy or the like which is used to lower the contact resistance between the two, and a layer formed by the AuBe alloy or the like between the metal electrode 9 and the p-type AlGaAs layer 20 in the light extraction region side. The bonding alloying layer 9a is formed. As shown in FIG. 3, both the main light extraction region 2 of the p-type A1GaAsj 2〇 and the side light extraction region 2〇s of the laminate are formed by chemical etching to form a surface roughness protrusion. The portions 40f and 50f. The surface rough protrusions 4〇f are formed by bringing the flat (100) crystal main surface into contact with an etching liquid for surface roughening to be described later, and forming the side main light extraction region 20S. (eg {1 〇〇} facets are also formed by anisotropic etching By forming the surface rough protrusions 40f and 5Of, the thickness of the p-type AlGaAs layer 20 is increased to increase the side surface area, and the light extraction efficiency of the light-emitting element 100 is greatly improved. A method of manufacturing the light-emitting element 100. First, as shown in step 2, as shown in step 2, as shown in step 2, as shown in step 2, as shown in FIG. The main surface, epitaxial growth, good GaAs buffer layer 2, and then epitaxial growth of the n-type AlGaAs layer 90 Γ η plus κ 1 dopant is Te). Next, as shown in step 3 of FIG. 5, on top of it, the ruthenium crystal grows the p-type AlGaAs layer 20 (the p-type dopant is Zn or c), and the layers of the layers of the upper layer. Crystal growth is carried out by well-known liquid phase growth method. P-type AlGaAs layer 20 λ λ bauxite μ

After the completion of the growth of Bu, the step 4 is carried out, and the GaAs substrate 1 is chemically etched and removed by using a gas/hydrogen peroxide mixed solution or the like. When the above steps are performed by the gentleman, _. 卜, ...... East, as shown in step 5 of Fig. 6, by the splash or vacuum steaming method, the first main surface of the oyster-type AlGaAs layer 20 and the η-type AlGaAs The γ and the main surfaces of the layer 90 are respectively formed to form a bonding layer for forming a bonding alloy layer, and then the bonding alloying layers 9a and 15c are formed by heat treatment (that is, sintering treatment) for alloying (refer to FIG. ; omitted in Figure 6). Then, the light extraction region side electrode 9 and the inner surface electrode 15 are formed so as to cover the bonding alloying layers 9a, i & respectively, thereby forming the light emitting element crystal W. Then, the light-emitting element wafer W is immersed in the pre-treatment liquid ρτ ’, and the first main surface of the p-type Al GaAs layer 2 露出 exposed around the light extraction region side electrode 9 is pretreated. Next, as shown in the subsequent step 6, in the main light extraction region ((1〇〇) main surface) of the p-type AlGaAs layer 20, an anisotropic etching is performed using the surface roughness etching liquid FEA to form a surface rough protrusion. Department 4〇f. The surface is thick and etched with money, which is an aqueous solution containing acetic acid, hydrofluoric acid, supplemental acid, 峨11 200832762 and water. Specifically, acetic acid (in terms of ch3cooh); is contained in the following range: · 37.4 %% or more and 94.8 mass% Hydrofluoric acid (in terms of HF): 0.4% by mass or more and 148% by mass. Nitric acid (in terms of HN〇3): K3 mass% or more and 14 7 masses or less, block (in terms of "conversion": 0.12 The mass % or more 〇 84 mass 2 = lower 0 Μ; and the water content is 2.4% by mass or more and 45% by mass or less is contained in the following range: 仏

Acetic acid (in terms of CH3COOH): 45.8 or less; mass% or more and 94.8 mass% Hydrofluoric acid (in terms of HF): 5.5 mass% or more U 8 mass ❶ or less · ash xiao acid (in hn 〇 3 conversion): K6 mass % or more, 7 7 f, μ iodine (in terms of I2): 〇 _ 15% by mass or more 〇 84% by mass or less. The water content is 2.4% by mass, 丨 32 7% by mass or less, and the temperature is 40 t; . (: The following is appropriate. $ system, can be exemplified as acetic acid ^

quality. /. A composition of 5% acidity of A, 5% by mass of nitric acid, 3 mass% of moth, and 8 mass% of water. , Li, and, pre-treatment liquid water mixing ratio is 5 : 1 : 1). 96% sulfuric acid·· 30% hydrogen peroxide water can be used: 1 or more and 20·· 1 ··1 or less (for example, 5 ^ on the first main surface side of the p-type AlGaAs layer 20 of the wafer before dicing, When the surface roughening treatment is performed without performing the above pretreatment, the protrusion formation state due to the surface thick chain, particularly the protrusion shape or the protrusion height, is likely to be uneven. In particular, as in the present embodiment, # is formed by the light extraction surface. Until 12,200832762, the thickness of the surface layer of the Pn joint surface is small. If the deep-cut protrusion is formed locally, the valley adjacent to the protrusion reaches the p_n joint interface J and the surface layer (P-type AlGaAs layer 20) When the surface is interrupted, the current diffusion state in the surface is deteriorated, and the light extraction efficiency is likely to be lowered. Such a deep protrusion is used in the hydrofluoric acid etching solution or the tannic acid liquid solution used in Patent Document 6 It is particularly easy to form in the case of mixing an exclusive solution of sulfuric acid, nitrate, and acid mixed acid.

On the other hand, the above-mentioned residual solution used in the present invention has a very significant and sensitive etching selectivity to the low-energy surface of A1GaAs, so that the selective etching is caused even by slight strain or crystal defects. Sexually rapid reduction 'usually does not cause minor friction problems, etc., and may also result in the formation of areas with insufficient surface roughness. However, the rough surface surname used in the present invention, when used in AlGaAs _, can be more smoothly (four) than the surface roughening (four) liquid used in the prior art described above, and is less likely to form the interface Ρ·η bonding interface J. Part of the deep protrusion. The main point is that the production of the pre-fabricated wafer can be prevented by the "pre-treatment of the pre-treatment liquid" of the sulfuric acid hydrogen peroxide before the surname can be used to prevent the formation of deep protrusions as described above. The improvement has a significant help. Back to Figure 6' When the surface of the main light extraction area is finished with a thick chain protrusion, the melon becomes 0 inch' with 2 <110> directions to borrow the pelletizer from the wafer ^ A main surface side is formed in the form of #DG, and is diced into individual wafers: when the dicing is performed, as shown in step 7 of Fig. 6, the density of crystal defects is formed to be the same as that of the processing and shelling layer 2〇D. Most of the crystal defects in layer 20D will cause leakage current or scattering during luminescence conduction, so = 13 200832762 step 8 shows the processing loss gold & 9 lb. layer 20D to remove the damage layer for the damage layer The DEA is chemically etched to remove the etchant DEA, and the sulfuric acid-hydrogen peroxide aqueous solution having a lower sulfuric acid content than the above-mentioned ruthenium treatment solution can be used. Sulfuric acid can be used: hydrogen peroxide: water With an amount ratio of 20: 1: 1 by.

Then, as shown in step 9, the surface roughened sugar is contacted with the (four) liquid FEA to remove the side surface of the wafer from which the damage layer 20D has been removed, and anisotropic etching is performed on the side of the p-type A·layer 20 to form a surface rough protrusion. . Further, in the present embodiment, the wafer w is adhered to the substrate 60 through the adhesive sheet, and the wafer w is completely diced in this state, and the surface rough projections are formed on the entire surface of the laminated body. f. Further, regarding the side surface, the direction in which the projections 5〇f are formed is 90 degrees out of the light extraction surface side ☆ large I 40f, and the p_n joint surface is not broken. Therefore, the influence of uneven formation of the projections 50f (the above-mentioned partial deep projections) is small, so that the pre-treatment liquid ρτΑ can be omitted. Further, the surface etching liquid FEA' is limited to the side surface, and may be a hydrofluoric acid-based etching liquid, a nitric acid-based etching liquid, or a mixed acid system of mixed sulfuric acid and nitric acid, as known in the patent document. Liquid instead. When the surface of the side light extraction area 20S is formed by the rough protrusion 50f, if the etching liquid is not affected to affect the main light extraction area 2〇p of the surface rough protrusion 40f, step 7~ As shown by one of the chain lines in Fig. 9, the main light extraction region 2〇p is masked by the etching portion. Further, the main light extraction region 2〇ρ<the surface roughening protrusion is formed without the knives, and the main light extraction region 20ρ is combined with the side light extraction region 2〇s 14 200832762 to form the surface rough protrusion 40f. With 50f. In this case, before the surface roughening treatment is performed on both the main light extraction region 2〇p and the side light extraction region 2〇s, the pretreatment liquid pTA is pretreated. ^ After the separated light-emitting element wafer, the second main surface side is passed through the water layer and then on the metal stage, and as shown in FIG.

The final light-emitting element can be completed by connecting the bonding wires 17 and forming an outer core portion made of an epoxy resin (not shown). BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side cross-sectional view showing one of light-emitting elements to which the present invention is applied. j t Figure 2, a schematic view of the top view of Figure 1. Amount: A diagram of the surface rough protrusion formed by the layered body of Fig. 1. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 5 is a view showing the steps of the method of manufacturing the light-emitting element of Fig. 1. Fig. 6' is an explanatory view of the steps following Fig. 5. Figure 7 is a diagram illustrating the influence of the reporters and the squadrons. [Main component symbol description] 1 substrate 2 n-type GaAs buffer layer 15 200832762 9 light extraction region side electrode 9a bonding alloying layer 15 inner surface electrode 15c bonding alloying layer 17 bonding wire 20 p-type AlGaAs layer 20D processing damage layer 20M resistance Eclipse

20p main light extraction area 20S side light extraction area 40f surface rough protrusion 50f surface roughness protrusion 60 substrate 61 adhesive sheet 90 n-type AlGaAs layer 100 light-emitting element

DEA etchant for removing damage layer DG groove FEA etching solution for rough surface PTA pretreatment liquid W wafer 16

Claims (1)

200832762 X. Patent application: 1. A method for manufacturing a light-emitting element, characterized in that the following steps are carried out in the following order: The light-emitting element wafer manufacturing step is to be composed of a composition formula (AlxGai_xAs (where, 0 < χ < The n-type Al GaAs layer and the P-type A1 GaAs layer respectively formed by the compound are laminated to form a laminate by forming a p_n junction to fabricate a light-emitting element wafer; the main light extraction region surface roughening step 'by etching with surface roughness The liquid surface of the laminated body is anisotropically formed to form a surface coarse sugar protrusion; the etching liquid contains 90% by mass or more of acetic acid, hydrogen = acid, nitric acid, hydrazine and water, and acetic acid and hydrogen Fluoric acid "The total mass content of the mixture of the acid and the iodine is higher than that of the water. 2. The method for producing the light-emitting element according to the first aspect of the patent application, the surface roughness step of the main light extraction region Previously, the pre-implementation processing step will be performed as the ?A1GaAs layer or p-type: the main surface used for the light extraction surface of the laminate, and the hydrogen persulfate solution The treatment liquid is contacted for pretreatment. 3: The method for producing a light-emitting element according to item 2 of the patent application, wherein the & H system uses 96% sulfuric acid: the ratio of the peroxygen to the ratio is 5:1:1 or more. 20:1:1 or less. 迕4方,: the method of applying the light-emitting element of any of the items in the scope of the patent range, the agricultural φ is located on the side of the light extraction layer and the surface of the thin layer * The method of manufacturing the light-emitting element of the fourth aspect of the patent of the fourth aspect of the invention, wherein the light extraction surface is formed by the p-type AlGaAs layer. Type: as the next page. 18