TW201914051A - Method of manufacturing light-emitting element - Google Patents

Abstract

The present invention provides a method for manufacturing a light-emitting element, which is configured to reduce the cleavage failure rate when the light-emitting element is separated from the semiconductor substrate having the lattice-mismatched window layer and the support substrate by scribing and cleaving. A light-emitting layer portion is formed by epitaxially growing a first semiconductor layer, an active layer and a second semiconductor layer on a substrate through a lattice matching material, and a window layer and the support substrate are formed by epitaxially growing a material lattice-mismatched with the light-emitting layer portion. The substrate is removed to form a first ohmic electrode on the first semiconductor layer, a removal portion is formed by at least removing the first semiconductor layer and the active layer, and a second ohmic electrode is formed on the second semiconductor layer of the removal portion or on the window layer and the support substrate, thereby manufacturing a semiconductor substrate at least having the light-emitting layer portion excluding the removal portion, the first ohmic electrode and the second ohmic electrode on the window layer and the support substrate. The light-emitting element is separated from the semiconductor substrate by scribing and cleaving. Through the reverse side formed with the surface of the light-emitting layer portion of the semiconductor substrate, a groove having a residual thickness of 70 [mu]m or less is formed in the window layer and the support substrate, and the light-emitting element is separated by scribing and cleaving. Then, the surface side is formed on the light-emitting layer portion of the semiconductor substrate and the surface of the semiconductor substrate is marked along the groove. A force perpendicular to the semiconductor substrate is applied to the entire length or a portion of the groove to separate the light-emitting element. The groove is formed by a wet or dry etching.

Description

Manufacturing method of light emitting element

The present invention relates to a method for manufacturing a light-emitting element, and more particularly, to a method for manufacturing a light-emitting element including a step of separating the light-emitting element from the semiconductor substrate by scoring and splitting.

Products such as chip direct package (COB) are LED chip mounting methods that have good heat dissipation from LED elements and are used in applications such as lighting. When LEDs are mounted in COBs or the like, they must be flip-chip mounted where the wafer is directly bonded to the substrate. In order to achieve flip-chip mounting, a flip-chip having conductive pads having different polarities on the surface of one side of the light-emitting element must be fabricated. In addition, the surface on the opposite side of the surface on which the pads for conducting electricity are provided must be made of a material having a light extraction function.

When a flip-chip is produced from yellow to red LEDs, an AlGaInP-based material is used as the light-emitting layer. Since the AlGaInP-based material does not have bulk crystals, and the LED part is formed by an epitaxial method, the starting substrate will choose a material different from AlGaInP. Most of the starting substrates are GaAs or Ge, and these substrates have the characteristic of absorbing light in visible light. Therefore, when a flip-chip is fabricated, the starting substrate is removed.

However, the epitaxial layer forming the light emitting layer is an extremely thin film, so it cannot stand on its own after the starting substrate is removed. Therefore, it is necessary to replace the starting substrate with a material and a structure that have a function of a window layer that is slightly transparent to the light emission wavelength as a light emitting layer and a thickness sufficient to make it stand on its own as a supporting substrate.

As a replacement material having a function of a window layer and supporting a substrate, GaP, GaAsP, sapphire, and the like are selected. Regardless of the choice of any of the above materials, they are all materials different from AlGaInP-based materials, so the mechanical properties such as lattice constant, thermal expansion coefficient, and Young's coefficient will be different from those of AlGaInP-based materials.

As such a technique, Patent Document 1 discloses a method of growing GaP crystals to form a window layer and supporting a substrate.

Here, an example of a method of manufacturing a conventional light-emitting device with a flip-chip structure will be described using FIGS. 3 (a) to (d).

When manufacturing an AlGaInP-based epitaxial wafer, as shown in FIG. 3 (a), a GaAs substrate, for example, which is inclined 15 degrees in the [001] direction, is prepared as the starting substrate 300. Then, on the GaAs substrate 300, a first formed by (Al _x Ga _{1- x} ) _y In _{1 - y} P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) is formed by a metal organic vapor deposition (MOVPE) method. Active layer 302 formed by semiconductor layer (N cladding layer) 301, (Al _x Ga _{1- x} ) _y In _{1 - y} P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6), and (Al _x Ga _{1- x} ) A second semiconductor layer (P clad layer) 303 formed of _y In _{1 - y} P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) is stacked as the light emitting layer portion 307. Then, an intermediate composition layer 304 formed by Ga _y In _{1 - y} P (0.0 ≦ y ≦ 1.0) and a GaP window layer 305 having a thickness of 0.5 μm or more are sequentially stacked. These manufacturing methods are not limited to the MOVPE method, and may be manufactured by a molecular beam epitaxial (MBE) method or a chemical beam epitaxial (CBE) method.

Then, it is in contact with the GaP window layer to form a window layer and support substrate 306 made of GaAs _z P _1-z (0.0 ≦ z ≦ 0.1). Although the window layer and supporting substrate 306 can also be formed by the MOVPE method or the MBE method, a low-cost and fast deposition hydride vapor deposition (HVPE) method can also be suitably used. The thickness may be, for example, about 100 μm.

Then, as shown in FIG. 3 (b), after the window layer and support substrate 306 is formed, a wafer 031 is formed by removing the GaAs substrate 300 of the AlGaInP-based epitaxial wafer by chemical etching. The chemical etching solution is preferably one having an etching selectivity with an AlGaInP-based material, and is generally removed with an etchant containing ammonia.

Then, as shown in FIG. 3 (c), after the GaAs substrate is removed, a first ohmic electrode 351 is formed on the first semiconductor layer (lower cladding layer) 301 of the wafer 031, and at least the first semiconductor layer ( After the region (removed portion) 320 in which a part of the lower cladding layer 301 and the active layer 302 are cut away is formed, a second ohmic electrode 361 is formed in a part of the removed portion 320.

Then, the first semiconductor layer (the lower cladding layer 301) is located in at least a part of the region 311 without the first ohmic electrode 351 among the regions (non-removed portions) 310 other than the region 320 (the removed portion). Dielectric Substance 340. In addition, a dielectric portion 341 may be provided in at least a part of the step portion 330 between the region 310 and the region 320. Then, a semiconductor substrate A03 having a dielectric portion 342 in at least a part of the region 321 other than the second ohmic electrode 361 in the region 320 can be obtained.

In addition, although the case where all the dielectric portions 340, 341, and 342 are provided is shown in FIG. 3 (c) as an example, the same effect can be obtained even when all of the dielectric portions 340, 341, and 342 are provided. In addition, although the structure having only the dielectric portion 340 is exemplified in the region 311, a light reflecting film or a light reflecting portion may be provided between the dielectric portion 340 and the region 311 of the first semiconductor layer 301, or A light reflecting film or a light reflecting portion may be provided on the surface side of the region 311 where the dielectric portion 340 is not in contact with the first semiconductor layer 301.

In addition, although the case where there is a flat surface in the area 311 is shown as an example, it may be a surface having unevenness. Regarding the surface with unevenness, it may be a simple rough surface by wet etching, a carved rough surface with a cut surface, or a patterned rough surface patterned by photolithography with a pitch of tens of μm to hundreds of nm. Or a photonic rough surface with a trench shape having a pitch of several to several hundred nm.

In addition, although the stepped portion 330, the region (removed portion) 320, and the window layer and support substrate 306 are flat surfaces having no unevenness, they may be uneven surfaces. Regarding the surface with unevenness, it may be a simple rough surface by wet etching, a carved rough surface with a cut surface, or a patterned rough surface patterned by photolithography with a pitch of tens of μm to hundreds of nm. Or a photonic rough surface having a trench shape with a pitch of several to several hundred nm. Moreover, although the structure which does not have any film on the surface of a window layer and support substrate 306 is shown as an example, you may provide the antireflection film made of a dielectric substance.

Then, as shown in FIG. 3 (d), a scribe process is performed on the second surface 03B of the semiconductor substrate A03 along the cleavage preparation line 381 to give a scribe mark 382. The scoring process can be performed with a load of 50 g using, for example, a four-point diamond blade. The scoring conditions are not limited to the aforementioned conditions, and it is also possible to use a majority point type or a few point type cutter head, and the load is not limited to this value.

In addition, it is not limited to a diamond blade, and scoring may be performed by a laser ablation method. When the laser ablation method is used, a scribe process can be performed using, for example, a laser having a wavelength of 355 nm and outputting 0.5 W.

After the scoring process, the protective film is placed on the surface of the second surface 03B, and the blade is pressed against the surface opposite to the protective film surface (the first surface 03A) to perform a splitting process, and the light-emitting element is crystallized to separate the light-emitting element. , Thereby manufacturing a light emitting element. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-005551

[Problems to be Solved by the Invention] However, in a semiconductor substrate in which a window layer and a supporting substrate are formed of a material with a lattice mismatch system such as GaP, graining is performed by scribing and splitting. The window layer and supporting substrate originally have high-density crystal defects (differential rows), and it is difficult to extend the defect line with the degree of physical force of the scribe, and as a result, badly split crystal grains are often generated.

In order to reduce the frequency of occurrence of cracking, although the frequency of occurrence can be reduced by increasing the pressure applied during the cracking, it will become a "cracking and destruction" process that is not based on the defect line, so the yield cannot be improved.

In view of the above-mentioned problems, an object of the present invention is to provide a method for manufacturing a light-emitting element, which can reduce the semiconductor layer that supports the light-emitting element from a window layer such as GaP having a lattice mismatch system and a substrate by scribing and cleaving. Defective cleavage when the substrate is separated. [Technical means to solve problems]

In order to solve the above-mentioned problem, the present invention provides a method for manufacturing a light-emitting element, including the following steps. On a substrate, a first semiconductor layer is grown at least in order by epitaxial growth on a substrate that is a lattice matching material with the substrate system. , An active layer, and a second semiconductor layer to form a light-emitting layer portion; the window layer and the supporting substrate are epitaxially grown on the light-emitting layer portion by using a material that does not match the light-emitting layer system as a lattice mismatch. The window layer and the support substrate are removed; the substrate is removed; a first ohmic electrode is formed on the surface of the first semiconductor layer; at least the first semiconductor layer and the active layer are removed to form a removed portion; the second semiconductor layer in the removed portion or Forming a second ohmic electrode on the window layer and supporting substrate; thereby manufacturing a semiconductor substrate having at least a light emitting layer portion other than the removed portion, the first ohmic electrode, and The second ohmic electrode is then separated from the semiconductor substrate by scribing and cleaving to separate the light emitting element, thereby manufacturing the light emitting element; wherein the separation of the light emitting element is A groove having a thickness of 70 μm or less is left in the window layer and the supporting substrate by forming a surface opposite to the light-emitting layer portion forming surface side of the semiconductor substrate, and then forming a surface from the light-emitting layer portion of the semiconductor substrate. A scratch is made on the surface of the semiconductor substrate along the trench, and a force perpendicular to the semiconductor substrate is applied to the entire length or part of the trench to separate the light emitting element.

In the method of manufacturing such a light-emitting device, a groove having a thickness of 70 μm or less in the window layer and supporting substrate is formed on the surface opposite to the light-emitting layer portion forming surface side of the semiconductor substrate. When the light-emitting layer portion is made of a material of a lattice mismatch system, and the window layer and the supporting substrate are epitaxially grown, the defect rate in the scribe and cleaving steps can also be reduced.

In this case, the trench is preferably formed by wet etching or dry etching.

According to these methods, a trench having a desired depth can be reliably formed. [Contrast with the effect of the prior art]

According to the manufacturing method of the light-emitting element of the present invention, when the light-emitting element is separated from a semiconductor substrate having a window layer such as GaP having a lattice mismatch system and a supporting substrate by scoring and cleaving, the cleaving can be reduced. Defective rate, and high-quality light-emitting elements can be manufactured with high productivity.

As described above, in a semiconductor substrate in which a window layer and a supporting substrate are formed of a lattice-mismatching material such as GaP, when scoring and splitting are used to crystallize, a window layer and a supporting substrate such as GaP Originally, it has high-density crystal defects (differential rows), and it is difficult to extend the defect line by the physical force of the scoring degree. As a result, the problem of poorly split crystal grains often occurs.

At this time, the present inventors have actively discussed many times in order to solve such problems. As a result, a surface opposite to the light-emitting layer portion forming surface side of the semiconductor substrate was found, and a groove having a thickness of 70 μm or less remained in the window layer and the supporting substrate, and then grains were scribed and split. As a result, the defect rate caused by grain formation can be reduced, thereby completing the present invention.

In other words, the present invention provides a method for manufacturing a light-emitting element, which includes the following steps. On the substrate, at least one of a first semiconductor layer and an active layer is sequentially grown by epitaxial growth with a material that is a lattice matching system with the substrate system. And the second semiconductor layer to form a light-emitting layer portion; the window layer and the supporting substrate are epitaxially grown on the light-emitting layer portion by using a material that is lattice-incompatible with the light-emitting layer portion to form the window layer and A support substrate; removing the substrate; forming a first ohmic electrode on the surface of the first semiconductor layer; removing at least the first semiconductor layer and the active layer to form a removing portion; the second semiconductor layer in the removing portion or the window Forming a second ohmic electrode on the layer and supporting substrate; thereby manufacturing a semiconductor substrate having at least a light emitting layer portion other than the removed portion, the first ohmic electrode, and the second on the window layer and supporting substrate; The ohmic electrode is then used to separate the light-emitting element from the semiconductor substrate by scribing and cleaving, thereby manufacturing the light-emitting element; wherein the light-emitting element is separated by The light emitting layer portion forming surface side of the semiconductor substrate is a surface on the opposite side, and a groove having a thickness of 70 μm or less in the window layer and supporting substrate is formed, and then the light emitting layer portion forming surface side of the semiconductor substrate follows the light emitting layer portion forming surface side. The groove is scribed on the surface of the semiconductor substrate, and a force perpendicular to the semiconductor substrate is applied to the entire length or a part of the groove to separate the light emitting element.

Hereinafter, the first embodiment and the second embodiment of the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto. It should be noted that the first embodiment differs from the second embodiment only in the method of forming the trenches, and the other steps can basically be performed in the same manner. First, common steps in the first half of the first embodiment and the second embodiment will be described with reference to (a) to (c) in FIG. 1 and (a) to (c) in FIG. 2.

Initially, as shown in FIGS. 1 (a) and 2 (a), when producing an AlGaInP-based epitaxial wafer, initial substrates 100 and 200 such as GaAs, which are inclined 15 degrees in the [001] direction, are prepared. .

Then, on the substrates 100 and 200, at least one of the first semiconductor layers 101, 201, the active layers 102, 202, and the second semiconductor layer are sequentially grown by epitaxial growth using a material that is a lattice matching system with the substrates 100 and 200. 103 and 203 to form light emitting layer portions 107 and 207.

Specifically, when a GaAs substrate is used as the substrates 100 and 200, the (Al _x Ga _{1- x} ) _y In _{1 - y} P (0 ≦) is formed on the GaAs substrate by an organic metal vapor deposition (MOVPE) method. x cladding layer (first semiconductor layer) 101, 201 formed by x ≦ 1, 0.4 ≦ y ≦ 0.6; (Al _x Ga _{1- x} ) _y In _{1 - y} P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) active coating layer 102, 202; (Al _x Ga _{1- x} ) _y In _{1 - y} P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) P coating layer (second (Semiconductor layer) 103 and 203 are sequentially epitaxially grown to form light emitting layer portions 107 and 207. Then Ga _y In ₁ may be _{- y P (0.0 ≦ y ≦} 1.0) formed by the intermediate layer composition and the GaP window layer 104, 204 having a thickness of more than 0.5μm 105 and 205 are sequentially stacked.

These manufacturing methods are not limited to the MOVPE method, and may be manufactured by a molecular beam epitaxial (MBE) method or a chemical beam epitaxial (CBE) method.

Then, the window layer and support substrates 106 and 206 are epitaxially grown on the light emitting layer portion by using a material that does not match the lattice of the light emitting layer portions 107 and 207. Specifically, a GaAs _z P _1-z (0.0 ≦ z ≦ 0.1) window layer is also supported by epitaxial growth of a GaAs _z P _1-z (0.0 ≦ z ≦ 0.1) that is in lattice mismatch with the light emitting layer portions 107 and 207 by contacting the GaP window layers 105 and 205. The substrates 106 and 206 can form the window layer and the supporting substrates 106 and 206 on the light emitting layer portions 107 and 207. Although the window layer and support substrates 106 and 206 can also be formed by the MOVPE method or the MBE method, a cheap and fast-growing hydride vapor deposition (HVPE) method can also be suitably used. The thickness may be 20 to 200 μm, for example, about 100 μm.

After the window layer and support substrates 106 and 206 are formed, as shown in FIG. 1 (b) and FIG. 2 (b), a step of removing the substrates 100 and 200 is performed. For example, the GaAs substrates 100 and 200 of the AlGaInP-based epitaxial wafer are removed by chemical etching to form wafers 011 and 012. The chemical etching solution is preferably one having an etching selectivity with an AlGaInP-based material, and is generally removed with an etchant containing ammonia.

Then, as shown in (c) of FIG. 1 and (c) of FIG. 2, after removing the substrates 100 and 200, the first cladding layers (first semiconductor layers) 101 and 201 of the wafers 011 and 021 are formed to form first layers. An ohmic electrode 151, 251, and then at least the first semiconductor layers 101, 201 and the active layers 102, 202 are removed to form a removal portion 120, 220, the second semiconductor layer 103, 203 in the removal portion 120, 220, or a window layer Second ohmic electrodes 161 and 261 are formed on the supporting substrates 106 and 206.

Then, among the non-removed portions (regions other than the removed portions 120 and 220) 110 and 210, the dielectric portions 140 and 240 may be provided in at least a part of the regions 111 and 211 having no first ohmic electrodes 151 and 251.

In addition, dielectric portions 141 and 241 may be provided in at least a part of the step portions 130 and 230 between the non-removed portions 110 and 210 and the removed portions 120 and 220.

Next, among the removing portions 120 and 220, dielectric portions 142 and 242 may be provided in at least a part of the regions 121 and 221 other than the second ohmic electrodes 161 and 261. The semiconductor substrates A01 and A02 manufactured as described above have the light-emitting layer portions 107 and 207 other than the removed portions 120 and 220 at least on the window layer and support substrates 106 and 206; the first ohmic level 151 and 251 and the Second ohmic electrodes 161, 261.

Although this embodiment has exemplified the case where all the dielectric portions 140, 240; 141, 241; 142, 242 are provided, the same effect can be obtained even if all of the dielectric portions 140, 240; 141, 241; 142, 242 are required. In addition, in this embodiment, although the structures 111 and 211 of the first semiconductor layers 101 and 201 have only the dielectric portions 140 and 240, the dielectric portions 140 and 240 and the first semiconductor may be used. A light reflecting film or a light reflecting portion is provided between the regions 111 and 211 of the layers 101 and 201, or the dielectric portions 140 and 240 may not be in contact with the surface side of the regions 111 and 211 of the first semiconductor layers 101 and 201 A light reflecting film or a light reflecting portion is provided.

In addition, in this embodiment, although the case where the regions 111 and 211 have a flat surface is shown as an example, it may be a surface having unevenness. Regarding the surface with unevenness, it may be a simple rough surface by wet etching, a carved rough surface with a cut surface, or a patterned rough surface patterned by photolithography with a pitch of tens of μm to hundreds of nm. Or a photonic rough surface with a trench shape having a pitch of several to several hundred nm.

In this embodiment, the stepped portions 130 and 230; the removed portions 120 and 220 and the window layer and support substrates 106 and 206 are flat surfaces having no unevenness, but they may be uneven surfaces. Regarding the surface with unevenness, it may be a simple rough surface by wet etching, a carved rough surface with a cut surface, or a patterned rough surface patterned by photolithography with a pitch of tens of μm to hundreds of nm. Or a photonic rough surface having a trench shape with a pitch of several to several hundred nm.

In addition, although the structure in which the surfaces of the window layer and support substrates 106 and 206 are not provided with any film is exemplified, an anti-reflection film made of a dielectric may be provided.

So far, the first embodiment and the second embodiment have exactly the same steps. After that, as shown in (d) and (e) of FIG. 1 and (d) and (e) of FIG. 2, the surface opposite to the light emitting layer portion forming surface of the semiconductor substrates A01 and A02 is opposite to the surface (ie, The first surfaces of the window layer and support substrates 106 and 206) 01A and 02A form grooves 180 and 280 having a thickness of 70 μm or less in the window layer and support substrates 106 and 206, and the light emitting layer portions from the semiconductor substrates A01 and A02. The surface (01B, 02B) side is formed with scratches 182, 282 along the grooves on the surface of the semiconductor substrate, and a force perpendicular to the semiconductor substrate is applied to the entire length or part of the grooves 180, 280 to separate the light-emitting elements. step. The trench formation method includes a case of wet etching (first embodiment) and a case of dry etching (second embodiment), which will be described in detail below.

First, the first embodiment will be described with reference to (d) and (e) of FIG. 1. As shown in FIG. 1 (d), 1 μm SiO _{2 is} formed on a surface (ie, the first surface having a window layer and supporting substrate 106) 01A opposite to the light-emitting layer portion formation surface side of the semiconductor substrate A01. In the film, the area of the cleavage preparation line 181 provided in advance is an opened SiO ₂ pattern 170 by photolithography. The larger the width of the opening 171 is, the easier the etching is, and it may be, for example, 25 μm. The width of the opening portion 171 is not limited to 25 μm, and may be a width of 1/20 or more with respect to the etching depth.

Then, apply the electronic wax to the surface (second surface) 01B on the opposite side of the light emitting layer portion forming surface 01A of the semiconductor substrate A01 having the SiO ₂ pattern 170, and mix hydrochloric acid and nitric acid in a ratio of 1: 3. In the etching solution, the opening 171 is etched. Etching of about 1 μm can be performed by immersion for about 5 minutes. Then, while the etching solution is kept warm, it is controlled through time management to achieve a desired trench depth. At this time, the trench 180 is formed so that the residual thickness in the window layer and support substrate 106 becomes 70 μm or less.

Then, as shown in FIG. 1 (e), the second surface 01B of the semiconductor substrate A01 provided with a desired trench depth is provided along the trench 180 (that is, along the cleavage preparation line 181). The scoring process of scoring 182. The scoring process can be performed with a load of 50 g using a 4-point diamond blade, for example. The scoring conditions are not limited to the aforementioned conditions, and it is also possible to use a majority point type or a few point type cutter head, and the load is not limited to this value.

In addition, it is not limited to a diamond blade, and scoring may be performed by a laser ablation method. When the laser ablation method is used, for example, a laser with a wavelength of 355 nm and an output power of 0.5 W can be used for the scoring process.

After the scribe process, a force perpendicular to the semiconductor substrate A01 is applied to the entire length or a part of the trench 180 to separate the light emitting element. At this time, the protective film can be placed on the surface of the second surface 01B, and the blade can be abutted from a surface opposite to the protective film surface to perform a cleaving treatment, thereby crystallizing.

Next, the second embodiment will be described using (d) and (e) of FIG. 2. A 1 μm SiO ₂ film is formed on a surface opposite to the light-emitting layer portion formation surface side of the semiconductor substrate A02 (that is, the first surface of the semiconductor substrate A02 having a window layer and supporting substrate 206) 02A, and by photolithography, A region of the cleavage preparation line 281 provided in advance is an opened photoresist pattern 290. The larger the width of the opening 271 is, the easier the etching is, and it may be, for example, 25 μm. The width of the opening portion 171 is not limited to 25 μm, and it may be a width of 1/20 or more with respect to the etching depth.

The wafer A02 having the photoresist pattern 290 is put into a hydrofluoric acid solution to obtain a SiO ₂ pattern 270 which is slightly the same as the photoresist pattern 290. After the SiO ₂ pattern 270 is formed, the photoresist pattern 290 is removed by organic washing and ashing.

The first surface 02A of the wafer A02 having the SiO ₂ pattern 270 is subjected to a treatment including, for example, a plasma of chlorine gas, and the opening 271 is etched. Cl ₂ can be used as the plasma source of chlorine gas, and ICP can be used as the plasma application method. The output power applied by the plasma may be, for example, 150W. It is then controlled through time management to achieve the desired trench depth. At this time, the trench 280 is formed so that the residual thickness in the window layer and support substrate 206 becomes 70 μm or less.

The conditions shown above are just examples and are not limited to the above conditions. SiCl ₄ or BCl ₃ can be selected as the source and gas for the plasma generation of chlorine gas, and RIE can also be selected as the plasma application method. As long as the output power is 50W or more, etching can be performed.

On the second surface 02B surface of the semiconductor substrate A02 on which the desired trench depth is provided, the second surface 02B is opposite to the first surface 02A, and a score 282 is provided along the trench 280 (that is, along the cleavage preparation line 281). Scratch processing. Scribing can be performed using a 4-point diamond blade with a load of 50g. The scoring conditions are not limited to the aforementioned conditions, and it is also possible to use a majority point type or a few point type cutter head, and the load is not limited to this value.

In addition, it is not limited to a diamond blade, and scoring may be performed by a laser ablation method. When the laser ablation method is used, for example, a laser with a wavelength of 355 nm and an output power of 0.5 W can be used for the scoring process.

After the scribe process, a force perpendicular to the semiconductor substrate A02 is applied to the entire length or a part of the trench 280 to separate the light emitting element. At this time, the protective film can be placed on the surface of the second surface 02B, and the blade can be abutted from a surface opposite to the protective film surface to perform a cleaving process, thereby crystallizing.

As described above, the grooves 180 and 280 having a thickness of 70 μm or less in the window layer and supporting substrates 106 and 206 are formed on the surfaces 01A and 02A opposite to the light-emitting layer portion forming side of the semiconductor substrates A01 and A02. The light emitting layer portion of the semiconductor substrate is formed on the surface side, and the surface of the semiconductor substrates A01 and A02 is provided with scratches 182 and 282 along the grooves, and a force perpendicular to the semiconductor substrate is applied to the entire length or a part of the grooves 180 and 280 to separate them. The light-emitting element can reduce the defective rate of cleavage when the light-emitting element is separated from a semiconductor substrate having a window layer such as GaP having a lattice mismatch system and a supporting substrate by scoring and cleavage.

When grooves having a residual thickness of more than 70 μm are formed in the window layer and support substrate, when grooves are not formed, and when grooves are formed on the light-emitting layer portion formation surface side of the semiconductor substrate, the cracking failure rate becomes high. [Example]

Examples and comparative examples of the present invention are shown below to describe the present invention more specifically, but the present invention is not limited to these.

(Examples 1 to 5) According to the first embodiment of the method for manufacturing a light-emitting element of the present invention shown in FIG. 1, a light-emitting element was manufactured. First, as shown in FIG. 1, a substrate made of GaAs (001) is prepared as a starting substrate 100, and a double hetero layer (light emitting layer portion 107) sufficient as a functional layer is formed on this substrate by the MOVPE method. The light emitting layer portion 107 is a stack of a lower cladding layer (first semiconductor layer) 101, an active layer 102, and an upper cladding layer (second semiconductor layer) 103 in this order.

The first semiconductor layer 101 has a composition of (Al _x Ga _{1- x} ) _y In _{1 - y} P (0.6 ≦ x ≦ 1.0, 0.4 ≦ y ≦ 0.6). In this embodiment, an n-type AlInP cladding layer is used as A two-layer structure of 0.7 μm (an impurity concentration of 3.0 × 10 ¹⁷ / cm ³ ) and an n-type Al _0.85 GaInP layer of 0.3 μm (an impurity concentration of 1.0 × 10 ¹⁷ / cm ³ ) was used as the first semiconductor layer.

The active layer 102 is selected from (Al _x Ga _{1- x} ) _y In _{1 - y} P (0.15 ≦ x ≦ 0.8, 0.4 ≦ y ≦ 0.6), and the composition of x and y is changed according to the wavelength. In this embodiment, multiple active layers are used for the active layer. The film thicknesses of the active layer and the barrier layer are changed according to the required wavelength, and they are adjusted individually in accordance with the wavelength within a range of 4 to 12 nm.

A two-layer structure with a p-type AlInP cladding layer of 0.9 μm (parameter concentration 3.0 × 10 ¹⁷ / cm ³ ) and a p-type Al _0.6 GaInP layer of 0.1 μm (parameter concentration 1.0 × 10 ¹⁷ / cm ³ ) was used as the first layer. Two semiconductor layers 103.

A film of a buffer layer (intermediate composition layer 104) made of GaInP is formed on the light emitting layer portion 107. A window layer made of GaP of about 100 μm and a film supporting the substrate 106 is formed on the buffer layer by MOVPE and HVPE methods. .

After the window layer and support substrate 106 is formed, as shown in FIG. 1 (b), the substrate 100 is removed by a wet etching method as a free standing substrate, and a first ohmic electrode 151 is formed on a surface from which the substrate 100 is removed. The first ohmic electrode 151 is made of an Au electrode containing Si, Zn, and S, and has a film thickness of 1.5 μm.

Then, as shown in FIG. 1 (c), a part of the light-emitting layer portion 107 is cut off by a photolithography method and an etching method, and a light-emitting layer region 110 (non-removed portion) and a region where the window layer and support substrate are exposed (removed) are provided. Department) 120.

Next, a second ohmic electrode 161 is formed on the window layer and support substrate 106 of the removal portion 120. The second ohmic electrode 161 is made of an Au electrode containing Be, and has a film thickness of 1.5 μm.

Next, as shown in FIG. 1D, a 1 μm SiO ₂ film is formed on the first surface (01A) of the semiconductor substrate A01 having the window layer and the support substrate 106. The area of the cleavage preparation line 181 is set as the opened SiO ₂ pattern 170 by photolithography. The opening width is 25 μm.

Then, an electronic wax is applied to the second surface (01B) opposite to the first surface (01A) of the semiconductor substrate having the SiO ₂ pattern 170, and is put into an etching solution in which hydrochloric acid and nitric acid are mixed at a ratio of 1: 3. The opening 171 is etched to form a trench 180. As shown in Table 1, by changing the etching time, the residual thickness (trench thickness) of the trench 180 in the window layer and support substrate 106 is changed. At this time, the trench 180 is formed so that the remaining thickness in the window layer and support substrate 106 becomes 70 μm or less.

Then, as shown in FIG. 1 (e), a scribe process is performed along the cleavage preparation line 181 on the second surface (01B) of the semiconductor substrate provided with a desired trench depth. Scribing can be performed using a 4-point diamond blade with a load of 50g.

After the scoring process, the protective film was placed on the surface of the second surface 01B, and the blade was abutted from the surface opposite to the protective film surface to perform a cleavage process, and crystallized.

(Comparative Examples 1 to 3) A light-emitting device was manufactured in the same manner as in Example 1 except that the etching time was changed so that the remaining thickness in the window layer and supporting substrate of the trench was as shown in Table 1.

(Examples 6 to 10) The same method as in Example 1 was performed except that the openings were etched by the treatment with a chlorine-containing gas plasma and the remaining thickness of the trenches in the window layer and the support substrate was as shown in Table 1. Manufacturing of light-emitting elements. Cl _{2 was} used as the plasma source of chlorine gas, and ICP was used as the plasma application method. The output power applied by the plasma is 150W. It is then controlled through time management to achieve the desired trench depth. At this time, the trench was formed so that the residual thickness in the window layer and support substrate became 70 μm or less.

(Comparative Examples 4 to 6) A light-emitting element was produced in the same manner as in Example 6 except that the remaining thickness in the window layer and supporting substrate of the trench was as shown in Table 1.

(Examples 11 to 15) A light-emitting device was performed in the same manner as in Example 1 except that the thickness of the window layer and supporting substrate was about 120 μm, and the remaining thickness of the grooved window layer and supporting substrate was as shown in Table 1. Manufacturing.

(Comparative Examples 7 to 11) A light-emitting device was manufactured in the same manner as in Example 11 except that the remaining thickness in the window layer and supporting substrate of the trench was as shown in Table 1.

(Examples 16 to 20) A light-emitting device was performed in the same manner as in Example 6 except that the thickness of the window layer and supporting substrate was about 120 μm and the remaining thickness of the grooved window layer and supporting substrate was as shown in Table 1. Manufacturing.

(Comparative Examples 12 to 16) A light-emitting device was produced in the same manner as in Example 16 except that the remaining thickness in the window layer and supporting substrate of the trench was as shown in Table 1.

Tables 1 and 4 show the relationship between the residual thickness in the window layer and supporting substrate of the trenches and the defective rate (%) caused by scoring and splitting in Examples 1 to 10 and Comparative Examples 1 to 6. Tables 1 and 5 show the relationship between the residual thickness in the window layer and support substrate of the trenches of Examples 11 to 20 and Comparative Examples 7 to 16 and the defective rate (%) caused by scoring and splitting.

【Table 1】

As can be seen from Table 1, FIG. 4 and FIG. 5, in the examples in which grooves having a residual thickness of 70 μm or less were formed, the cracking failure rate could be reduced.

In addition, the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiment is an example, and anyone who has the same technical idea and substantially the same structure as those described in the patent application scope of the present invention to produce the same effect is included in the technical scope of the present invention.

011, 021, 031 ‧‧‧ wafer

01A, 02A, 03A‧‧‧ The surface opposite to the light-emitting layer portion forming surface side of the semiconductor substrate (the first surface)

01B, 02B, 03B‧‧‧ The surface of the light emitting layer portion of the semiconductor substrate forming surface side (second surface)

100, 200, 300‧‧‧ substrates

1 01, 201, 301‧‧‧First semiconductor layer

102, 202, 302‧‧‧ Active layer

103, 203, 303‧‧‧Second semiconductor layer

104, 204, 304‧‧‧ intermediate composition layer

105, 205, 305‧‧‧ window layer

106, 206, 306‧‧‧Window layer and supporting substrate

107, 207, 307‧‧‧‧Light-emitting layer department

110, 210, 310

111, 211, 311‧‧‧ in the non-removed portion, the region having no first ohmic electrode

120, 220, 320‧‧‧

121, 221, 321‧‧‧ except the area outside the second ohmic electrode

130, 230, 330‧‧‧ steps

140, 141, 142, 240, 241, 242, 340, 341, 342‧‧‧

151, 251, 351‧‧‧ first ohmic electrode

161, 261, 361‧‧‧ second ohmic electrode

170, 270‧‧‧SiO ₂ pattern

171, 271‧‧‧ opening

180, 280‧‧‧ groove

181, 281, 381‧‧‧ split preparation line

182, 282, 382‧‧‧ scratches

290‧‧‧Photoresist pattern

A01, A02, A03‧‧‧Semiconductor substrate

FIG. 1 is a schematic view showing a first embodiment of a method for manufacturing a light-emitting element according to the present invention. FIG. 2 is a schematic view showing a second embodiment of a method for manufacturing a light emitting device according to the present invention. FIG. 3 is a schematic view showing a method of manufacturing a conventional light emitting device. FIG. 4 is a graph showing the relationship between the residual thickness of the trench in the window layer and the support substrate and the defective rate (%) of scribe and split in Examples 1 to 10 and Comparative Examples 1 to 6. FIG. FIG. 5 is a graph showing the relationship between the residual thickness of the trench in the window layer and the supporting substrate and the defective rate (%) of scribe and split in Examples 11-20 and Comparative Examples 7-16.

Claims (2)

A method for manufacturing a light emitting element includes the following steps: On a substrate, at least one of a first semiconductor layer, an active layer, and a second semiconductor layer is sequentially grown by epitaxial growth with a material that is a lattice matching system with the substrate system. To form a light-emitting layer portion; epitaxially grow the window layer and supporting substrate on the light-emitting layer portion by using a material which is a lattice mismatch system with the light-emitting layer portion to form the window layer and supporting substrate; remove the A substrate; forming a first ohmic electrode on the surface of the first semiconductor layer; removing at least the first semiconductor layer and the active layer to form a removing portion; the second semiconductor layer in the removing portion or on the window layer and supporting substrate Forming a second ohmic electrode; thereby manufacturing a semiconductor substrate having at least a light-emitting layer portion other than the removed portion, the first ohmic electrode, and the second ohmic electrode on the window layer and supporting substrate, and thereafter, The light-emitting element is separated from the semiconductor substrate by scribing and cleaving to manufacture the light-emitting element. The light-emitting element is separated from the semiconductor substrate by The light emitting layer portion is formed on the opposite side of the surface, and a groove having a thickness of 70 μm or less in the window layer and the supporting substrate is formed, and then the groove is formed from the light emitting layer portion of the semiconductor substrate along the groove. A scratch is made on the surface of the semiconductor substrate, and a force perpendicular to the semiconductor substrate is applied to the entire length or a part of the trench to separate the light emitting element. The method for manufacturing a light emitting device according to claim 1, wherein the trench is formed by wet etching or dry etching.