JP2019096829A - Manufacturing method of light-emitting element - Google Patents

Abstract

To provide a manufacturing method of light-emitting element in which exfoliation of visible transparent adhesive from a juncture, by absorbing laser energy and being destroyed, is restrained in scribe braking step.SOLUTION: A manufacturing method of light-emitting element includes a step of forming a lamination structure including a luminous layer on a departure board, and forming a dielectric layer and a first adhesive layer 10 thereon thus manufacturing a wafer for light-emitting element, a step of preparing a visible transparent substrate 13, and a support substrate consisting of a dielectric layer and a second adhesive layer 15 formed thereon, a step of bonding the support substrate to a wafer for light-emitting element via a first and second adhesive layers, a step of exposing a first semiconductor layer by removing the departure board, a step of forming a removal part by removing a part of the first semiconductor layer and an active layer, a step of forming first and second ohmic electrodes, and a step of separating the light-emitting element from a bonding substrate, in die-shape, by using laser light scribe breaking method, where the adhesive layer in the scribe region is removed previously before scribe is carried out.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a light emitting device, and more particularly to a method of scribing and breaking a light emitting device from a semiconductor substrate.

  A product such as a chip on board (COB) is an LED chip mounting method which is excellent in heat dissipation from LED elements and is adopted in applications such as lighting. In the case of mounting an LED on a COB or the like, flip mounting in which a chip is directly bonded to a board is essential. In order to realize flip mounting, it is necessary to manufacture a flip chip in which conductive pads having different polarities are provided on one side of the light emitting element. Further, the surface opposite to the surface provided with the current-carrying pad needs to be made of a material having a light extraction function.

  When producing a flip chip with yellow to red LEDs, an AlGaInP based material is used for the light emitting layer. A bulk crystal does not exist in the AlGaInP based material, and the LED part is formed by an epitaxial method, so a material different from AlGaInP is selected as the starting substrate. Since the starting substrate is often selected from GaAs and Ge, and these substrates have the property of absorbing light to visible light, the starting substrate is removed when producing a flip chip. However, since the epitaxial layer forming the light emitting layer is an extremely thin film, it can not stand on its own after removal of the starting substrate. Therefore, it is necessary to replace the starting substrate with a material / structure having a function as a window layer which is transparent to the emission wavelength in the light emitting layer and has a thickness sufficient for self-supporting. is there.

  Patent Document 1 discloses a technique of bonding a light emitting layer to a transparent substrate having a function of a window layer / supporting substrate with an adhesive such as BCB (benzocyclobutene) to form an LED. A sapphire substrate or a quartz substrate is often selected as the transparent substrate in terms of flatness, hardness, and cost. After bonding the light emitting layer, the transparent substrate is cut and diced to make a light emitting element. However, in order to minimize kerf loss at the time of cutting, dicing by scribing and breaking is general, not dicing by a blade. . In the case of a sapphire substrate or a quartz substrate, the scribing method is generally performed by an ablation laser.

  At this time, a laser wavelength used is an ultraviolet wavelength range shorter than 360 nm in order to ablate a substrate transparent to visible light. BCB adhesives are transparent to visible light and have an absorption band to wavelengths in the ultraviolet region. That is, the absorption wavelength bands of the BCB adhesive and the visible transparent substrate are close to each other. When scribing a substrate obtained by bonding a light emitting layer and a visible transparent substrate with an adhesive having a light absorption band in the ultraviolet region with a laser, not only the transparent substrate but also a visible transparent adhesive such as a BCB adhesive absorbs laser energy , There was a problem that it was destroyed and exfoliated from the joint.

Patent document 1: JP-A-2004-158823

  The present invention has been made in view of the above problems, and a visible transparent adhesive is a laser in a scribing / braking step of scribing a substrate obtained by joining a light emitting layer and a transparent substrate with an adhesive having a light absorption band in the ultraviolet region. An object of the present invention is to provide a method of manufacturing a light emitting element in which absorption of energy, destruction and suppression of peeling from a junction are suppressed.

In order to achieve the above object, the present invention provides a method of manufacturing a light emitting device,
(1) forming a laminated structure including a light emitting layer portion in which a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially laminated by epitaxial growth on a starting substrate, thereby producing a wafer for a light emitting device;
(2) preparing a support substrate;
(3) bonding the supporting substrate to the wafer for light emitting devices through an adhesive layer to produce a bonded substrate;
(4) removing the starting substrate from the bonded substrate to expose the first semiconductor layer;
(5) removing at least the first semiconductor layer and the active layer in a partial region of the bonded substrate to form a removal portion;
(6) forming a first ohmic electrode on the surface of the first semiconductor layer, and forming a second ohmic electrode on the surface of the removal portion, and (7) the bonding substrate using a scribing / breaking method using a laser beam. Separating the light emitting element from the
And a method of manufacturing a light emitting device in which the adhesive layer in the scribe region is removed in advance before scribing.

  According to the manufacturing method of such a light emitting element, the adhesive is not broken in the area to be scribed in the scribing / breaking step, thereby suppressing the adhesive from being broken and peeling from the bonding portion. it can.

  In the step (7), the adhesive layer in the scribe area is preferably removed before scribing.

  According to the method of manufacturing such a light emitting element, it is possible to relatively easily make the adhesive not present in the scribe region.

  In the step (2), preferably, the support substrate has an adhesive layer, and the adhesive layer is removed and processed so that the adhesive layer does not exist in a scribe region. .

  Even in this case, the adhesive can be relatively easily removed from the scribe area.

  Further, it is preferable that the width of the region where the adhesive is not present be 20 μm or more in the direction perpendicular to the scribing direction.

  By setting the width of the region where such an adhesive is not present, a dramatic peel improvement effect can be obtained.

  As described above, the method of manufacturing a light emitting device according to the present invention is visible in a scribing and breaking step of scribing a substrate obtained by bonding a light emitting layer and a transparent substrate with an adhesive having a light absorption band in the ultraviolet region. It is possible to suppress that the transparent adhesive absorbs laser energy, is destroyed, and exfoliated from the joint.

It is explanatory drawing of the scribe in the manufacturing method of the light emitting element of this invention. It is the schematic of the light-emitting element wafer produced by 1st embodiment. It is the schematic when a 1st bonding layer is formed in the light emitting element wafer produced by 1st embodiment. It is the schematic of the support substrate prepared by 1st embodiment. It is the schematic of the joining substrate formed in 1st embodiment. It is the schematic of the joining substrate which exposed the 1st semiconductor layer of 1st embodiment. It is the schematic of the joining substrate which formed the removal part of 1st embodiment. It is the schematic of the joining substrate which formed the opening part in the dielectric material layer of 1st embodiment. It is the schematic of the joining substrate in which the 1st ohmic electrode of 1st embodiment and the 2nd ohmic electrode were formed. It is the schematic of the joining board | substrate which formed the coating part and opening part of the resist of 1st embodiment. It is the schematic of the joining substrate in which the exposed part of 1st embodiment was formed. It is the schematic of the scribed joined board | substrate of 1st embodiment. It is the schematic of the light-emitting element wafer produced by 2nd embodiment. It is the schematic when a 1st joining layer is formed in the light emitting element wafer produced by 2nd embodiment. It is the schematic of the support substrate prepared by 2nd embodiment. It is the schematic of the support substrate which formed the pattern in the contact bonding layer of 2nd embodiment. It is the schematic of the joining substrate formed in 2nd embodiment. It is the schematic of the joining substrate which exposed the 1st semiconductor layer of 2nd embodiment. It is the schematic of the joining substrate which formed the removal part of 2nd embodiment. It is the schematic of the joining substrate which formed the opening part in the dielectric material layer of 2nd embodiment. It is the schematic of the joining substrate in which the 1st ohmic electrode of 2nd embodiment and the 2nd ohmic electrode were formed. It is the schematic of the joining board | substrate which formed the coating part and opening part of the resist of 2nd embodiment. It is the schematic of the joining substrate which formed the exposed part of 2nd embodiment. It is the schematic of the scribed joined board | substrate of 2nd embodiment. It is the schematic of the joining board | substrate which formed the coating part and opening part of the resist of a comparative example. It is the schematic of the joining substrate which exposed the intermediate composition layer which exists in the scribe area | region of a comparative example. It is the schematic of the scribed joined board | substrate of a comparative example. It is a figure which shows the relationship between the width | variety of the exposed part in an Example and a comparative example, and a peeling part area.

  As described above, the visible transparent adhesive absorbs laser energy in the scribing / breaking process of scribing a substrate obtained by joining a light emitting layer and a transparent substrate (supporting substrate) with an adhesive having a light absorption band in the ultraviolet region. It has been desired to develop a method of manufacturing a light emitting device in which it is suppressed from being broken and separated from the bonding portion.

  As a result of intensive investigations on the above problems, the present inventors conducted scribing and breaking in a method of manufacturing a light emitting device in which a scribing and breaking process is performed by laser light to separate the light emitting device from the semiconductor substrate in a die shape. The inventors have found that peeling off from the bonding portion can be suppressed by removing the adhesive in the area to be scribed in the process beforehand so that the adhesive layer does not exist, and the present invention has been completed.

That is, the present invention is a method of manufacturing a light emitting device,
(1) forming a laminated structure including a light emitting layer portion in which a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially laminated by epitaxial growth on a starting substrate, thereby producing a wafer for a light emitting device;
(2) preparing a support substrate;
(3) bonding the supporting substrate to the wafer for light emitting devices through an adhesive layer to produce a bonded substrate;
(4) removing the starting substrate from the bonded substrate to expose the first semiconductor layer;
(5) removing at least the first semiconductor layer and the active layer in a partial region of the bonded substrate to form a removal portion;
(6) forming a first ohmic electrode on the surface of the first semiconductor layer, and forming a second ohmic electrode on the surface of the removal portion, and (7) the bonding substrate using a scribing / breaking method using a laser beam. Separating the light emitting element from the
And before the scribing, the adhesive layer in the scribing region is removed in advance.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[Step (1)]
Step (1) forms a laminated structure including a light emitting layer portion in which a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially laminated by epitaxial growth on a starting substrate, to produce a wafer for a light emitting device It is a process.

  The wafer for light emitting element manufactured in the step (1) includes a light emitting layer portion in which a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially stacked, and in addition to the light emitting layer portion, for example, a light emitting layer portion An etch stop layer can be formed between the and the starting substrate. In addition, an intermediate composition layer, a GaP current diffusion layer, a first dielectric film and the like can be further formed on the light emitting layer portion. The light emitting device wafer may have a first adhesive layer for bonding a supporting substrate to be described later and the light emitting device wafer on top of these layers. In the present invention, a light emitting device wafer can be produced by sequentially laminating these layers on the starting substrate. The starting substrate is not particularly limited, but may be a GaAs or Ge substrate, and the first semiconductor layer, the active layer, and the second semiconductor layer may be AlGaInP based.

[Step (2)]
Step (2) is a step of preparing a support substrate.

  The support substrate prepared in the step (2) comprises at least a visible transparent substrate. A sapphire substrate, a quartz substrate, etc. can be used as a visible transparent substrate. A dielectric film can be formed on the visible transparent substrate, and a second adhesive layer can be formed on the dielectric film for bonding the above-described wafer for light emitting device and the support substrate.

  In the step (2), when the support substrate has the second adhesive layer, the second adhesive layer is processed into a desired pattern by photolithography or the like to remove the adhesive layer in the scribe region. be able to.

[Step (3)]
The step (3) is a step of bonding the supporting substrate to the wafer for light emitting element through an adhesive layer to produce a bonded substrate.

  At this time, it is preferable that at least one of the supporting substrate and the light emitting element wafer have an adhesive layer. The adhesive that can be used here is not particularly limited, and BCB, epoxy resin, polyvinyl chloride resin, urethane resin, acrylic resin, silicone and the like can be mentioned.

[Step (4)]
The step (4) is a step of removing the starting substrate in the bonded substrate to expose the first semiconductor layer.

  In the step (4), the starting substrate of the bonded substrate is removed by etching or the like. Furthermore, with the etch stop layer, the etch stop layer can also be removed. By removing these layers, the first semiconductor layer is exposed.

[Step (5)]
The step (5) is a step of removing at least the first semiconductor layer and the active layer in a partial region of the bonding substrate to form a removing portion.

  In the step (5), at least the first semiconductor layer and the active layer are cut and removed to form a removal portion. Further, not only the first semiconductor layer and the active layer but only the visible transparent substrate may be left, and all the layers may be cut and removed to form a removal portion.

[Step (6)]
The step (6) is a step of forming a first ohmic electrode on the surface of the first semiconductor layer and forming a second ohmic electrode on the surface of the removal portion.

  In the step (6), for example, the electrode can be formed by the following method. First, a dielectric layer is formed on the surface of the bonded substrate on which the removal portion is formed in the step (5). Next, an opening (a portion where the first semiconductor layer and the removed portion are exposed) is formed in the dielectric layer by photolithography and wet etching. Then, in the opening portion, the first ohmic electrode is formed on the surface of the first semiconductor layer, and the second ohmic electrode is formed on the surface of the removal portion.

[Step (7)]
The step (7) is a step of separating the light emitting element from the bonded substrate in a die shape using a scribing / breaking method with a laser beam.

  In the step (7), first, in the scribe area, only the visible transparent substrate is left, and all layers are removed. If the adhesive layer in the scribe area is not removed in step (2), the adhesive layer can be removed at the same time.

  Next, as shown in FIG. 1, after the adhesive layer (the first adhesive layer 10 and the second adhesive layer 15) is removed to form a scribe portion 28 by laser light in the scribe region where the visible transparent substrate 13 is exposed, Breaking is performed to separate the light emitting elements into dies.

  According to the manufacturing method of the light emitting element as described above, the adhesive is not destroyed in the scribing / breaking step, thereby suppressing the adhesive from being broken and peeling from the bonding portion. Can.

  In addition, the adhesive layer in the scribing region may be removed any time before scribing, but immediately before scribing in the step (7) or when preparing the support substrate in the step (2). Can be done relatively easily. In addition, by setting the width of the area where the adhesive does not exist to be 20 μm or more in the direction perpendicular to the scribing direction, the adhesive layer does not have to be irradiated with the laser light reliably, so the dramatic improvement in peeling is achieved. can get.

  Hereinafter, although the manufacturing method of the light emitting element of this invention is demonstrated in more detail, referring a figure using 1st embodiment and 2nd embodiment, this invention is not limited to this .

First Embodiment
[Step (1)]
First, the first embodiment of the present invention will be described. As shown in FIG. 2, the wafer 1 for light emitting elements is formed on a GaAs substrate (starting substrate) 2 inclined by 15 degrees in, for example, the [001] direction by metal organic chemical vapor deposition (MOVPE) method (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6), an etch stop layer 3 having a thickness of 0.1 to 1.0 m, and a thickness of 0.5 to 0.5 m Thickness 0 of the first conductive type first semiconductor layer 4 of 1.0 μm and (Al _x Ga _{1 -x} ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) active layer ₅ of .1～1.0Myuemu, thickness 0.5 consisting of _{(Al x Ga 1-x)} y in 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) second conductive type second semiconductor layer ₆ of _{1.0μm, Ga y in 1-y} P Ga with (0.0 ≦ y ≦ 1.0) the intermediate composition layer thickness of 7,0.5~20μm consisting It can be formed by sequentially stacking a current diffusion layer 8.

  The manufacturing method of the wafer 1 for light emitting elements is not limited to MOVPE, and may be manufactured by a molecular beam epitaxy (MBE) method or a actinic ray epitaxy (CBE) method. Although not shown, a buffer layer may be provided between the GaAs substrate and the first semiconductor layer.

Further, as shown in FIG. 3, in the light emitting device wafer 1, a first dielectric film 9 made of SiO ₂ or SiN _x is further formed on the GaP current diffusion layer 8 to a thickness of, for example, 0.4 μm. The first bonding layer 11 can be provided by forming the first bonding layer 10 on which the BCB adhesive is applied by spin coating. The thickness of the first adhesive layer varies depending on the viscosity of the BCB adhesive and the rotation speed at the time of spin coating. For example, the first adhesive layer 10 of about 0.5 μm can be formed at a rotation speed of 5000 rpm. Although the first bonding layer 11 is provided in the present embodiment, the wafer for a light emitting element used in the present invention has a structure without the first bonding layer 11, a structure without the first dielectric film 9, or a first bonding The structure without the layer 10 may be used.

[Step (2)]
In the supporting substrate 30, as shown in FIG. 4, a dielectric film 14 made of, for example, SiO ₂ or SiN _x is formed on a visible transparent substrate 13 such as sapphire or quartz, and an adhesive made of, for example, BCB resin is further formed thereon. By applying the agent to form the second adhesive layer 15, the second bonding layer 12 can be provided. The thickness of the second adhesive layer 15 varies depending on the viscosity of the BCB adhesive and the spin speed during spin coating, but in the present embodiment, the second adhesive layer 15 of about 0.5 μm can be formed at a rotational speed of 5000 rpm. When the first adhesive layer 10 is formed, the second adhesive layer 15 may not be provided, and when the second adhesive layer 15 is formed, the first adhesive layer 10 may not be provided, and both may be formed. You may In addition to the BCB resin as an adhesive, the first adhesive layer 10 and the second adhesive layer 15 may be formed of another transparent and liquid member such as epoxy, such as epoxy.

[Step (3)]
Next, as shown in FIG. 5, the first adhesive layer 10 and the second adhesive layer 15 are opposed to each other, and pressure and heat are applied under vacuum or reduced pressure atmosphere to form the first adhesive layer 10 and the second adhesive layer 15. The bonded substrate 16 is formed. The pressure can be adhered by pressure bonding under the conditions of 6 N / cm ² or more and the temperature of 100 ° C. or more. In particular, bonding is preferably performed under conditions of reaching 30 N / cm ² and 300 ° C.

[Step (4)]
Next, as shown in FIG. 6, the GaAs substrate 2 is removed from the bonding substrate 16 by chemical etching. The chemical etching solution is preferably one having etching selectivity with the AlGaInP based material, and is generally removed by using an ammonia containing etchant. After the GaAs substrate 2 is removed, the etch stop layer 3 is removed to form a bonded substrate 17 having a first semiconductor layer exposed surface (first surface) 18. The etch stop layer 3 is removed by a mixed solution of hydrogen peroxide and an acid for etching the AlGaInP based material.

[Step (5)]
Next, as shown in FIG. 7, a part of the first semiconductor layer exposed surface 18 is cut away from the bonding substrate 17 to form a removal portion (second surface) 19. In this aspect, the first semiconductor layer 4 and the active layer 5 are removed to expose the second semiconductor layer 6.

[Step (6)]
Next, a dielectric layer 21 is formed and an opening 22 is provided so as to cover the notched side surface 20 as shown in FIG. The dielectric layer 21 is preferably SiO ₂ or SiN _x . Any of sol-gel method, sputtering method and CVD method can be selected for film formation of the dielectric layer. The openings 22 can be provided by forming the dielectric layer 21, forming a mask by photolithography, and forming an exposed portion by wet etching using BHF.

  Next, as shown in FIG. 9, the first ohmic electrode 23 is formed on a part of the first semiconductor layer exposed surface 18, and the second ohmic electrode 24 is formed on a part of the removal portion 19.

[Step (7)]
Next, as shown in FIG. 10, a covering 25 and an opening 26 are formed to cover the entire first semiconductor layer exposed surface 18 and a part of the removing portion 19 by photolithography using a photoresist.

Next, as shown in FIG. 11, the opening 26 is removed by dry etching to expose a portion 27 of the visible transparent substrate 13. The dry etching here removes the adhesive layer in the scribe area. The removal of the AlGaInP layer is performed in a mixed atmosphere of Cl-containing gas and Ar in the ICP apparatus, and the removal of the SiO ₂ or SiN _x dielectric layer and the BCB layer is performed in a mixed atmosphere of F-containing gas and Ar Can. The pressure atmosphere can be 0.5 Pa, and the output can be plasma 300 W. The removal of the layer using the Cl-containing gas and the removal of the layer using the F-containing gas can be performed in separate chambers, or in the same chamber only by switching the gas without removing the wafer from the vacuum atmosphere. It can also be implemented.

  Next, as shown in FIG. 12, after the formation of the exposed portion 27, the covering portion 25 with the photoresist is removed. After removing the covering portion 25, the exposed portion 27 is irradiated with a laser to form a scribe portion 28. Then, the breaking process is performed along the scribing unit 28 and diced.

  According to the method of the first embodiment, since the adhesive layer does not exist in the laser irradiation area, the adhesive absorbs the laser energy and is broken, and it is relatively easy to suppress the peeling from the bonding portion. Can be manufactured.

Second Embodiment
[Step (1)]
Next, a second embodiment of the present invention will be described. As shown in FIG. 13, the wafer 1 for light emitting element is formed on a GaAs substrate (starting substrate) 2 inclined by 15 degrees in the [001] direction by metal organic chemical vapor deposition (MOVPE) method (Al _x Ga _{1- x} ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6), an etch stop layer 3 having a thickness of 0.1 to 1.0 μm, and a thickness of 0.5 to 1. 0.1 μm thick first conductive first semiconductor layer 4, (Al _x Ga _{1 -x} ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) active layer ₅ of _{~1.0μm, (Al x Ga 1-} x) y in 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) having a thickness of 0.5 to 1. the second semiconductor layer ₆ the second conductivity type made of _{0μm, Ga y in 1-y} P Ga with (0.0 ≦ y ≦ 1.0) the intermediate composition layer thickness of 7,0.5~20μm consisting It can be formed by sequentially stacking a current diffusion layer 8.

  The manufacturing method of the wafer 1 for light emitting elements is not limited to MOVPE, and may be manufactured by a molecular beam epitaxy (MBE) method or a actinic ray epitaxy (CBE) method. Although not shown, a buffer layer may be provided between the GaAs substrate and the first semiconductor layer.

Further, as shown in FIG. 14, a wafer 1 for light emitting element is formed by forming a first dielectric film 9 made of, for example, SiO ₂ or SiN _x with a thickness of about 0.4 μm on the GaP current diffusion layer 8. It can have one bonding layer 11. Although the first bonding layer 11 is provided in the present embodiment, the first bonding layer 11 may not be provided.

[Step (2)]
As shown in FIG. 15, the supporting substrate 30 is an adhesive layer 15 on which a dielectric film 14 made of SiO ₂ or SiN _x is formed on a visible transparent substrate 13 such as sapphire or quartz, and a BCB adhesive is further applied thereon. The second bonding layer 12 can be provided by forming '. The thickness of the adhesive layer 15 'varies depending on the viscosity of the BCB adhesive and the rotation speed at the time of spin coating. For example, the adhesive layer 15' of 0.5 μm can be formed at a rotational speed of 5000 rpm.

  Next, as shown in FIG. 16, the adhesive layer 15 ′ is processed into the shape of the desired pattern 29. At this stage, the adhesive layer in the scribe area is removed. When a photosensitive material is selected among the BCB materials as the adhesive layer 15 ′, a desired pattern 29 can be obtained by a photolithography method. When a non-photosensitive material is selected from the BCB materials as the adhesive layer 15 ', a resist is coated by a photoresist method so that a desired pattern is obtained, and a desired pattern 29 is formed by an ICP apparatus containing F-containing gas. You can get Here, the shape and size of the pattern 29 are limited by the size of the light emitting element to be obtained and the thickness of the adhesive layer 15 '. The shape and size of the pattern 29 are equal to or less than the difference between the size of the light emitting element to be obtained and the opening 26.

[Step (3)]
Next, as shown in FIG. 17, the first bonding layer 11 and the second bonding layer 12 are opposed to each other, and pressure and heat are applied under a vacuum or reduced pressure atmosphere to form the first bonding layer 11 and the second bonding layer 12. The bonded substrate 16 is formed. It can adhere | attach by pressure bonding on pressure of 6 N / cm < ² > or more, and temperature 100 degreeC or more conditions. In particular, bonding is preferably performed under conditions of reaching 30 N / cm ² and 300 ° C.

[Step (4)]
Next, as shown in FIG. 18, the GaAs substrate 2 is removed from the bonding substrate 16 by chemical etching. The chemical etching solution is preferably one having etching selectivity with the AlGaInP based material, and is generally removed by using an ammonia containing etchant. After the GaAs substrate 2 is removed, the etch stop layer 3 is removed to form a junction substrate 17 having the first semiconductor layer exposed surface 18. The etch stop layer 3 is removed by a mixed solution of hydrogen peroxide and an acid for etching the AlGaInP based material.

[Step (5)]
Next, as shown in FIG. 19, the first semiconductor layer exposed surface 18 is left from the bonding substrate 17 in a range not exceeding the pattern 29, and a part of the first semiconductor layer exposed surface 18 is notched. Form

[Step (6)]
Next, dielectric layer 21 is formed and opening 22 is provided so as to cover notched side surface 20 as shown in FIG. The dielectric layer 21 is preferably SiO ₂ or SiN _x . Any of sol-gel method, sputtering method and CVD method can be selected for film formation of the dielectric layer. The openings 22 can be provided by forming the dielectric layer 21, forming a mask by photolithography, and forming an exposed portion by wet etching using BHF.

  Next, as shown in FIG. 21, the first ohmic electrode 23 is formed on a part of the first semiconductor layer exposed surface 18, and the second ohmic electrode 24 is formed on a part of the removal portion 19.

[Step (7)]
Next, as shown in FIG. 22, a cover 25 and an opening 26 are formed to cover the entire first semiconductor layer exposed surface 18 and a part of the removal portion 19 by photolithography using a photoresist.

Next, as shown in FIG. 23, the opening 26 is removed by dry etching to expose a portion 27 of the visible transparent substrate 13. The removal of the AlGaInP layer is performed in a mixed atmosphere of Cl-containing gas and Ar in the ICP apparatus, and the removal of the SiO ₂ or SiN _x dielectric layer and the BCB layer is performed in a mixed atmosphere of F-containing gas and Ar Can. The pressure atmosphere can be 0.5 Pa, and the output can be plasma 300 W. The removal of the layer using the Cl ₂ -containing gas and the removal of the layer using the F-containing gas can be performed in separate chambers, or in the same chamber only by switching the gas without removing the wafer from the vacuum atmosphere. Can also be implemented.

  Next, as shown in FIG. 24, after the formation of the exposed portion 27, the coated portion 25 with the photoresist is removed. After removing the covering portion 25, the exposed portion 27 is irradiated with a laser to form a scribe portion 28. Then, the breaking process is performed along the scribing unit 28 and diced.

  Even in the method of the second embodiment, since the adhesive layer does not exist in the laser irradiation area, the adhesive absorbs the laser energy, is destroyed, and the light emitting element which suppresses peeling from the joint is relatively made. It can be easily manufactured.

  EXAMPLES The present invention will be specifically described below using Examples and Comparative Examples, but the present invention is not limited to these.

Example 1
The light emitting device was manufactured based on the first embodiment of the method for manufacturing the light emitting device of the present invention as shown in FIGS.

  First, a wafer for light emitting element was manufactured. A substrate (starting substrate) made of GaAs (001) was prepared as a starting substrate, and a double hetero layer (light emitting layer) as a functional layer was formed on this substrate by the MOVPE method. The light emitting layer was formed by sequentially laminating a lower cladding layer (first semiconductor layer), an active layer, and an upper cladding layer (second semiconductor layer).

In the first semiconductor layer and the second semiconductor layer, the composition of (Al _x Ga _1-x ) _y In _1-y P (0.6 ≦ x ≦ 1.0, 0.4 ≦ y ≦ 0.6) is selected In the present embodiment, as the first semiconductor layer, the n-type AlInP cladding layer is 0.7 μm (doping concentration 3.0 × 10 ¹⁷ / cm ³ ), and the n-type Al _0.85 GaInP layer is 0.3 μm (doping) It was set as the two-layer structure of density | concentration 1.0 * 10 < ¹⁷ > / cm < ³ >.

The active layer is selected from (Al _x Ga _{1 -x} ) _y In _1-y P (0.15 ≦ x 0.8 0.8, 0.4 y y 0.6 0.6), and depending on the wavelength, the compositions x and y are changed. In this example, multiple active layers were used as the active layer. The film thickness of the active layer and the barrier layer was changed according to the wavelength to be obtained, and was adjusted to the wavelength in the range of 4 to 12 nm.

As the second semiconductor layer, the p-type AlInP cladding layer is 0.9 μm (doping concentration 3.0 × 10 ¹⁷ / cm ³ ), and the p-type Al _0.6 GaInP layer is 0.1 μm (doping concentration 1.0 × 10 ¹⁷⁾ It was set as the 2 layer structure of / cm < ³ >.

A buffer layer of GaInP was formed on the light emitting layer. Next, a dielectric film of SiO ₂ was formed to a thickness of 0.4 μm on the buffer layer, and a BCB adhesive was applied thereon by spin coating to form a first adhesive layer.

Next, the support substrate was prepared. First, a dielectric film composed of SiO ₂ was formed on sapphire, and a second adhesive layer coated with an adhesive composed of BCB resin was formed thereon.

  Next, in order to bond the light emitting wafer and the support substrate, the first adhesive layer and the second adhesive layer were adhered. Thereafter, the GaAs substrate was removed by an ammonia-containing etchant. Subsequently, the etch stop layer was removed to expose the first semiconductor layer. Next, a part of the first semiconductor layer and the active layer was cut out to expose a part of the second semiconductor.

Next, a dielectric layer was formed and an opening was provided so as to cover the notched side surface. The dielectric layer was SiO ₂ and was deposited by P-CVD using TEOS and O ₂ . The opening was formed by forming a dielectric layer, forming a mask by photolithography, and forming an exposed portion by wet etching using BHF.

Next, a first ohmic electrode and a second ohmic electrode were formed. Thereafter, part of the visible transparent substrate was exposed by photolithography and dry etching. At this time, the width of the exposed portion (direction perpendicular to the scribing direction) was 5, 10, 15, 20, 25, 30 μm. The removal of the AlGaInP layer was performed in a mixed atmosphere of Cl-containing gas and Ar in an ICP apparatus, and the removal of the SiO ₂ dielectric layer and the BCB layer was performed in a mixed atmosphere of F-containing gas and Ar. The pressure atmosphere was 0.5 Pa, and the output was 300 W plasma.

  After forming the exposed portion, the photoresist was removed, and laser was irradiated to form a scribed portion. The breaking process was performed along the scribing part and diced. FIG. 28 shows the relationship between the area of the bonded portion peeled off by the adhesive and the width of the exposed portion (street portion width). It can be seen that the peeling area is reduced regardless of the width of any exposed portion, as compared to the comparative example (width 0 μm) described later. Especially when the width was 20 μm or more, the peeling was dramatically improved.

Example 2
The light emitting device was manufactured based on the second embodiment of the method for manufacturing a light emitting device according to the present invention as shown in FIGS. A light emitting device was manufactured in the same manner as Example 1, except that the adhesive was processed into a desired pattern shape and then the transparent substrate was attached. FIG. 28 shows the results of the peeling state. Also in Example 2, the same result as in Example 1 was obtained.

[Comparative example]
The light emitting device was manufactured using the conventional method as shown in FIG. 25 to FIG. A light emitting device was manufactured in the same manner as Example 1, except that scribing was performed in the region where the adhesive was present. FIG. 28 shows the results of the peeling state. It can be seen that the peeling area is larger than in Examples 1 and 2.

  As described above, the method of manufacturing a light emitting device according to the present invention is visible in a scribing and breaking step of scribing a substrate obtained by bonding a light emitting layer and a transparent substrate with an adhesive having a light absorption band in the ultraviolet region. It has been found that the transparent adhesive can suppress laser energy absorption, destruction and peeling from the joint.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has the substantially same constitution as the technical idea described in the claims of the present invention, and the same effects can be exhibited by any invention. It is included in the technical scope of

1 ... wafer for light emitting device, 2 ... GaAs substrate (starting substrate),
3: Etch stop layer 4: 1st semiconductor layer 5: Active layer 6: 2nd semiconductor layer
7 intermediate composition layer 8 gap current diffusion layer 9 first dielectric film
10: first adhesive layer, 11: first bonding layer, 12: second bonding layer,
13 Visible transparent substrate 14 Dielectric film 15 Second adhesive layer 15 ′ adhesive layer
16: bonding substrate, 17: bonding substrate in which the first semiconductor layer is exposed,
18: first semiconductor layer exposed surface (first surface), 19: removal portion (second surface),
20: Notched side, 21: dielectric layer, 22: opening,
23: first ohmic electrode, 24: second ohmic electrode, 25: coating portion
26: Opening, 27: Exposed, 28: Scribed, 29: Desired pattern,
30 ... support substrate.

Claims (4)

A method of manufacturing a light emitting device,
(1) forming a laminated structure including a light emitting layer portion in which a first semiconductor layer, an active layer, and a second semiconductor layer are sequentially laminated by epitaxial growth on a starting substrate, thereby producing a wafer for a light emitting device;
(2) preparing a support substrate;
(3) bonding the supporting substrate to the wafer for light emitting devices through an adhesive layer to produce a bonded substrate;
(4) removing the starting substrate from the bonded substrate to expose the first semiconductor layer;
(5) removing at least the first semiconductor layer and the active layer in a partial region of the bonded substrate to form a removal portion;
(6) forming a first ohmic electrode on the surface of the first semiconductor layer, and forming a second ohmic electrode on the surface of the removal portion, and (7) the bonding substrate using a scribing / breaking method using a laser beam. Separating the light emitting element from the
And a method of manufacturing a light emitting device, wherein the adhesive layer in the scribe region is removed in advance before scribing.   The method according to claim 1, wherein in the step (7), the adhesive layer in the scribe region is removed before scribing.   In the step (2), the support substrate has an adhesive layer, and the adhesive layer is removed so that the adhesive layer does not exist in the scribe region. A method of manufacturing a light emitting device according to claim 1.   The method according to any one of claims 1 to 3, wherein the width of the region where the adhesive is not present is 20 μm or more in a direction perpendicular to the scribing direction.

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