LED chip, preparation method thereof and temporary substrate

Abstract

The application discloses an LED chip and a preparation method and a temporary substrate thereof. The method comprises the following steps: perforating a temporary substrate to obtain a target through hole penetrating through the temporary substrate; providing a sapphire substrate, wherein a first substrate surface of the sapphire substrate is a polishing surface; depositing a bonding layer with a preset thickness on a second substrate surface of the sapphire substrate; stacking the sapphire substrate on the temporary substrate, and bonding the sapphire substrate and the temporary substrate; performing a patterning process on the first substrate surface of the sapphire substrate; sequentially manufacturing an epitaxial layer and a chip structure layer on the patterned substrate to obtain an LED chip; fixing the LED chip on a grinding platform, introducing etching solution into the target through hole to corrode the bonding layer, and separating the temporary substrate from the sapphire substrate; and grinding the second substrate surface of the sapphire substrate to control the finished thickness of the LED chip. The application aims to reuse the temporary substrate to reduce the manufacturing cost of the LED chip.

Description

Technical Field

[0001] This invention relates to the field of semiconductor chip manufacturing technology, specifically to an LED chip, its preparation method, and a temporary substrate. Background Technology

[0002] Currently, blue and green light epitaxy is carried out on a 4-inch sapphire substrate by using MOCVD to epitaxially grow semiconductor light-emitting materials, and then using chip manufacturing processes to make finished chips. During this process, grinding technology is required to thin the substrate to the required chip thickness.

[0003] To reduce the warpage of sapphire substrates for epitaxial growth, the thickness of 4-inch sapphire substrates is typically 650µm. However, to actually manufacture finished chips, a thickness of less than 250µm is required. This necessitates grinding the 650µm substrate down to less than 250µm, resulting in a significant waste of sapphire substrate material, increased substrate costs, and consequently, high LED chip manufacturing costs. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide an LED chip and its preparation method, as well as a temporary substrate, in order to solve the technical problem of a large amount of waste of sapphire substrate in the LED chip preparation process in the prior art.

[0005] A first aspect of the present invention provides a method for fabricating an LED chip, the method comprising: A pre-defined temporary substrate is drilled to obtain a temporary substrate including a target through-hole, wherein the target through-hole penetrates the temporary substrate, and the first substrate surface of the temporary substrate is a bonding surface after polishing. A sapphire substrate is provided, wherein a first substrate surface of the sapphire substrate is a polished surface; A bonding layer of a predetermined thickness is deposited on the surface of a second substrate opposite to the surface of the first substrate on the sapphire substrate; The sapphire substrate is stacked on the temporary substrate, and the bonding layer is located between the temporary substrate and the sapphire substrate. The sapphire substrate and the temporary substrate are bonded using preset bonding parameters. The first substrate surface of the sapphire substrate is patterned to obtain a patterned sapphire substrate; An epitaxial layer and a chip structure layer are sequentially fabricated on the patterned substrate to obtain an LED chip. The LED chip is fixed on a preset grinding stage, and an etching solution is introduced into the target through hole to etch the bonding layer between the temporary substrate and the sapphire substrate, so that the temporary substrate is detached from the sapphire substrate. The surface of the second substrate of the sapphire substrate is ground to control the finished thickness of the LED chip.

[0006] According to one aspect of the above technical solution, the temporary substrate is made of a high-melting-point inert material with a melting point greater than 1100°C.

[0007] According to one aspect of the above technical solution, the thickness of the temporary substrate is 400μm-1000μm.

[0008] According to one aspect of the above technical solution, the diameter of the target via is 100μm-1000μm, the spacing between the target vias is 2000μm-10000μm, and the area of ​​the target via occupies a proportion of 1 / 5-1 / 3 of the area of ​​the temporary substrate.

[0009] According to one aspect of the above technical solution, the bonding layer is made of SiO2 material, and the thickness of the bonding layer is 2μm-5μm.

[0010] According to one aspect of the above technical solution, the total thickness of the temporary substrate, the bonding layer and the sapphire substrate is ≥550μm.

[0011] According to one aspect of the above technical solution, it specifically includes: The bonding layer surface attached to the sapphire substrate is polished. The surface of the bonding layer is activated and cleaned using a cleaning solution, which is a mixture of H2SO4, H2O2 and H2O, with a volume ratio of H2SO4, H2O2 and H2O of 7:3:1-10:4:1, and the cleaning time is 8-20 min.

[0012] According to one aspect of the above technical solution, the step of fixing the LED chip on a preset polishing stage and introducing an etching solution into the target through-hole to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby detaching the temporary substrate from the sapphire substrate, specifically includes: A fusible adhesive medium is coated between the chip structure layer of the LED chip and / or a preset grinding stage. The chip structure layer of the LED chip is fixed on the polishing stage by means of the fusible adhesive medium; An etching solution is coated onto the temporary substrate and introduced along the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby causing the temporary substrate to detach from the sapphire substrate.

[0013] A second aspect of the present invention is to provide an LED chip, which is prepared by the preparation method described in the above technical solution.

[0014] A third aspect of the present invention is to provide a temporary substrate obtained by detaching from an LED chip, the temporary substrate participating in the preparation of the LED chip in the preparation method described above, and being detached after the LED chip preparation is completed, so as to be reused in the LED chip preparation process.

[0015] Compared with the prior art, the advantages of using the LED chip, its preparation method, and temporary substrate shown in this invention are as follows: By providing a temporary substrate with targeted vias, a sapphire substrate is bonded to the temporary substrate via a bonding layer. The total thickness of the sapphire thin substrate, bonding layer, and temporary substrate is ≥650µm, solving the problem of difficult epitaxial growth caused by warping of the thin sapphire substrate. Furthermore, because the temporary substrate is designed with vias, etching solution can penetrate these vias to remove the bonding layer, allowing the temporary substrate to be separated from the sapphire thin substrate. This enables the temporary substrate to be reused; only the sapphire substrate needs to be ground to the required chip thickness, greatly reducing sapphire substrate waste and lowering LED chip manufacturing costs. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic flowchart of a method for preparing an LED chip according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a temporary substrate shown in an embodiment of the present invention; Figure 3 for Figure 2 A cross-sectional view; Figure 4 This is a schematic diagram of the LED chip fabrication process according to an embodiment of the present invention; Explanation of symbols in the attached drawings: Temporary substrate 10, first substrate surface 11, second substrate surface 12, target via 13, sapphire substrate 20, first substrate surface 21, second substrate surface 22, bonding layer 30, N-type semiconductor layer 40, quantum well layer 50, P-type semiconductor layer 60, chip structure layer 70. Detailed Implementation

[0017] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0018] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] A first aspect of the present invention provides a method for fabricating an LED chip, the method comprising steps S1-S8: Step S1: A hole is made in a preset temporary substrate to obtain a temporary substrate including a target through hole. The target through hole penetrates the temporary substrate. The first substrate surface of the temporary substrate is a bonding surface after polishing. Step S2: Provide a sapphire substrate, wherein the first substrate surface of the sapphire substrate is a polished surface; Step S3: Deposit a bonding layer of a predetermined thickness on the surface of the second substrate opposite to the surface of the first substrate on the sapphire substrate; Step S4: The sapphire substrate is stacked on the temporary substrate, the bonding layer is located between the temporary substrate and the sapphire substrate, and the sapphire substrate and the temporary substrate are bonded using preset bonding parameters; Step S5: Perform patterning processing on the first substrate surface of the sapphire substrate to obtain a patterned sapphire substrate. Step S6: An epitaxial layer and a chip structure layer are sequentially fabricated on the patterned substrate to obtain an LED chip; Step S7: Fix the LED chip on a preset grinding stage, and introduce an etching solution into the target through hole to etch the bonding layer between the temporary substrate and the sapphire substrate, so that the temporary substrate is detached from the sapphire substrate. Step S8: Grind the second substrate surface of the sapphire substrate to control the finished thickness of the LED chip.

[0021] Furthermore, the temporary substrate is made of a high-melting-point inert material with a melting point greater than 1100°C. The thickness of the temporary substrate is 400μm-1000μm. The density of the target vias on the temporary substrate is [not specified].

[0022] Furthermore, the bonding layer is made of SiO2 material, and the thickness of the bonding layer is 2μm-5μm. The total thickness of the temporary substrate, the bonding layer, and the sapphire substrate is ≥550μm.

[0023] Furthermore, the step of stacking the sapphire substrate on the temporary substrate, with the bonding layer located between the temporary substrate and the sapphire substrate, and bonding the sapphire substrate and the temporary substrate using preset bonding parameters, specifically includes: The bonding layer surface attached to the sapphire substrate is polished. The surface of the bonding layer is activated and cleaned using a cleaning solution, which is a mixture of H2SO4, H2O2 and H2O with a volume ratio of 7:3:1, and the cleaning time is 10 min.

[0024] Furthermore, the step of fixing the LED chip on a preset polishing stage and introducing an etching solution into the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby detaching the temporary substrate from the sapphire substrate, specifically includes: A fusible adhesive medium is coated between the chip structure layer of the LED chip and / or a preset grinding stage. The chip structure layer of the LED chip is fixed on the polishing stage by means of the fusible adhesive medium; An etching solution is coated onto the temporary substrate and introduced along the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby causing the temporary substrate to detach from the sapphire substrate.

[0025] A second aspect of the present invention provides an LED chip, which is prepared by the preparation method described in the above technical solution.

[0026] A third aspect of the present invention provides a temporary substrate obtained by detaching from an LED chip, the temporary substrate participating in the preparation of the LED chip in the preparation method described above, and being detached after the LED chip preparation is completed so as to be reused in the LED chip preparation process.

[0027] Compared with the prior art, the advantages of using the LED chip, its preparation method, and temporary substrate shown in this invention are as follows: By providing a temporary substrate with targeted vias, a sapphire substrate is bonded to the temporary substrate via a bonding layer. The total thickness of the sapphire thin substrate, bonding layer, and temporary substrate is ≥650µm, solving the problem of difficult epitaxial growth caused by warping of the thin sapphire substrate. Furthermore, because the temporary substrate is designed with vias, etching solution can penetrate these vias to remove the bonding layer, allowing the temporary substrate to be separated from the sapphire thin substrate. This enables the temporary substrate to be reused; only the sapphire substrate needs to be ground to the required chip thickness, greatly reducing sapphire substrate waste and lowering LED chip manufacturing costs.

[0028] Example 1 Please see Figures 1 to 4 The first embodiment of the present invention provides a method for fabricating an LED chip, the method comprising steps S11-S18: Step S11: A hole is made in a preset temporary substrate to obtain a temporary substrate including a target through hole. The target through hole penetrates the temporary substrate, and the first substrate surface of the temporary substrate is a bonding surface after polishing.

[0029] In this embodiment, the temporary substrate 10 is a high-melting-point inert material with a melting point greater than 1100°C, such as a glass substrate with a thickness of 500 μm.

[0030] By creating a number of target vias 13 on the temporary substrate, the target vias penetrate the temporary substrate. The diameter of the target vias is in the range of 100μm-1000μm, the spacing between the vias is in the range of 2000μm-10000μm, and the area of ​​the target vias accounts for 1 / 5-1 / 3 of the entire temporary substrate. This can effectively ensure the structural strength of the temporary substrate and enhance the role of the target vias on the temporary substrate.

[0031] Specifically, the target through hole is circular in shape, which facilitates processing and ensures that the hole wall is flat and smooth, making it less likely for cracks to form on the target substrate from the edge of the target through hole.

[0032] In this embodiment, the temporary substrate includes a first substrate surface 11 and a second substrate surface 12, corresponding to the front and back sides of the temporary substrate, respectively. The first substrate surface of the temporary substrate is a flat, polished surface and serves as the bonding surface of the temporary substrate. The second substrate surface is also a flat, polished surface; in some other feasible embodiments, the second substrate surface may also be rough.

[0033] It should be noted that the terms "first" and "second" in the context of the first substrate surface and the second substrate surface are merely for the convenience of describing the two surfaces of the temporary substrate in the embodiments, and there is only a difference in the order of description, without any special limitation.

[0034] Step S12: Provide a sapphire substrate, wherein the first substrate surface of the sapphire substrate is a polished surface.

[0035] It should be noted that the sapphire substrate 20 is an Al2O3 substrate. Sapphire has a very high hardness, second only to diamond among natural materials.

[0036] In this embodiment, the thickness of the sapphire substrate is 220 μm. The sapphire substrate includes a first substrate surface 21 and a second substrate surface 22, which correspond to the front and back sides of the sapphire substrate, respectively. The first substrate surface of the sapphire substrate is a flat, polished surface, which facilitates epitaxial deposition on the sapphire substrate. The second substrate surface of the sapphire substrate is also a flat, polished surface, which is the bonding surface of the sapphire substrate. In some other feasible embodiments, the second substrate surface may also be rough.

[0037] It should also be noted that the terms "first" and "second" in "first substrate surface" and "second substrate surface" are only used to facilitate the description of the two surfaces of the sapphire substrate in the embodiments, and there is only a difference in the order of description, without any special limitation.

[0038] Step S13: Deposit a bonding layer of a predetermined thickness on the second substrate surface opposite to the first substrate surface on the sapphire substrate.

[0039] In this embodiment, the bonding layer 30 is made of SiO2 material, specifically deposited in a PECVD or PVD equipment, and the thickness of the bonding layer is 3 μm.

[0040] Specifically, the bonding layer serves to bond the temporary substrate to the sapphire substrate to form an integral structure. The bonding layer can securely connect the temporary substrate and the sapphire substrate, and it can also be removed using special methods to separate the temporary substrate from the sapphire substrate.

[0041] Step S14: The sapphire substrate is stacked on the temporary substrate, the bonding layer is located between the temporary substrate and the sapphire substrate, and the sapphire substrate and the temporary substrate are bonded using preset bonding parameters.

[0042] In this embodiment, after aligning the first substrate surface of the temporary substrate with the second substrate surface of the sapphire substrate, the bonding layer exists in a pre-fixed state between the temporary substrate and the sapphire substrate. In the bonding equipment, the bonding temperature is controlled at 470°C and the bonding time is 20 minutes. After this bonding process, the temporary substrate will be bonded to the sapphire substrate to form an integral structure, which is equivalent to providing a temporary, thickened sapphire substrate in this embodiment.

[0043] Specifically, in this embodiment, the temporary substrate thickness is 500 μm, the bonding layer is 3 μm, and the sapphire substrate thickness is 230 μm. The total thickness of the temporary substrate, bonding layer, and sapphire substrate is 733 μm. That is, the thickness of the temporary sapphire substrate provided in this embodiment is 733 μm, which is greater than the requirement of a substrate thickness of not less than 650 μm when fabricating epitaxial layers and chip structure layers on sapphire substrates in the prior art.

[0044] By bonding a temporary substrate to the surface of a second substrate on a sapphire substrate, good structural strength is provided for epitaxial deposition on the sapphire substrate, which solves the problem that the thin sapphire substrate is difficult to epitaxially deposit due to warping.

[0045] Step S15: The first substrate surface of the sapphire substrate is patterned to obtain a patterned sapphire substrate.

[0046] In this embodiment, the process of patterning a sapphire substrate on the first substrate surface to obtain a patterned sapphire substrate is an existing technology. It can be prepared by referring to some other relatively mature substrate patterning preparation processes. This embodiment will not be described in detail.

[0047] Step S16: An epitaxial layer and a chip structure layer are sequentially fabricated on the patterned substrate to obtain an LED chip.

[0048] Similarly, in this embodiment, the fabrication of the epitaxial layer and the chip structure layer 70 on the patterned substrate are both existing technologies. The main structure of the epitaxial layer includes an N-type semiconductor layer 40, a quantum well layer 50, and a P-type semiconductor layer 60. These can be fabricated by referring to some other relatively mature LED chip fabrication methods. This embodiment will not elaborate on these methods.

[0049] Step S17: Fix the LED chip on a preset polishing stage, and introduce an etching solution into the target through hole to etch the bonding layer between the temporary substrate and the sapphire substrate, so that the temporary substrate is detached from the sapphire substrate.

[0050] In this embodiment, a preliminary LED chip has been obtained after step S16. However, since a temporary substrate is added to the bottom of the sapphire substrate in this embodiment, the temporary substrate needs to be separated from the preliminary LED chip before the final LED chip is formed. After the temporary substrate is separated, it is processed and then participates in the next LED chip manufacturing process. Thus, the temporary substrate can be reused several times.

[0051] It is easy to understand that in this embodiment, the temporary substrate is equivalent to the part of the sapphire substrate that is ground away in the prior art, and plays the same role. In the manufacturing of LED chips, the first step is to deposit crystals on the sapphire substrate, and then remove it to control the thickness of the finished LED chip.

[0052] In this embodiment, the step of fixing the LED chip on a preset polishing stage and introducing an etching solution into the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby detaching the temporary substrate from the sapphire substrate, specifically includes: A fusible adhesive medium is coated between the chip structure layer of the LED chip and / or a preset grinding stage. The chip structure layer of the LED chip is fixed on the polishing stage by means of the fusible adhesive medium; An etching solution is coated onto the temporary substrate and introduced along the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby causing the temporary substrate to detach from the sapphire substrate.

[0053] In this embodiment, the fusible adhesive medium is wax. When fixing the LED chip, the slightly molten wax is coated on the grinding stage, and the LED chip is placed on the slightly molten wax. When the temperature drops, the wax will solidify again, thereby fixing the LED chip on the grinding stage.

[0054] In this embodiment, the etching solution is a BOE etching solution, which has a certain degree of corrosivity, especially a strong corrosivity to the SiO2 of the bonding layer. After the BOE etching solution is coated on the temporary substrate, the BOE etching solution will penetrate into the bonding layer between the temporary substrate and the sapphire substrate along the target via. The BOE etching solution reacts chemically with the bonding layer to etch the bonding layer. After the bonding layer is etched, the temporary substrate can easily be detached from the sapphire substrate under external force, thereby obtaining an LED chip that is closer to the finished product, as well as a temporary substrate detached from the LED chip. This temporary substrate can be used to participate in the fabrication of the next LED chip.

[0055] Of course, when the temporary substrate is used in the fabrication of the next LED chip, the temporary substrate should be cleaned to remove the bonding layer remaining on the temporary substrate and the BOE etching solution remaining in the target via.

[0056] Step S18: Grind the second substrate surface of the sapphire substrate to control the finished thickness of the LED chip.

[0057] In this embodiment, after separating the temporary substrate on the initial LED chip, an LED chip that is closer to the finished product can be obtained. To obtain the finished LED chip, the substrate needs to be polished in order to control the thickness of the finished LED chip.

[0058] As described above, the thickness of the sapphire substrate in this embodiment is 230μm. If the thickness of the sapphire substrate in the LED chip is required to be 200μm, then only 30μm needs to be removed by grinding the sapphire substrate. This temporary substrate is used to thicken the sapphire substrate, and it can be reused after separation. In this way, only a thinner sapphire substrate needs to be provided for each LED chip manufacturing process, avoiding the need to grind away most of the sapphire material in each LED chip manufacturing process, saving a lot of sapphire material and reducing the manufacturing cost of the LED chip.

[0059] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for fabricating an LED chip, characterized in that, The method includes: A pre-defined temporary substrate is drilled to obtain a temporary substrate including a target through-hole, wherein the target through-hole penetrates the temporary substrate, and the first substrate surface of the temporary substrate is a bonding surface after polishing. A sapphire substrate is provided, wherein a first substrate surface of the sapphire substrate is a polished surface; A bonding layer of a predetermined thickness is deposited on the surface of a second substrate opposite to the surface of the first substrate on the sapphire substrate; The sapphire substrate is stacked on the temporary substrate, and the bonding layer is located between the temporary substrate and the sapphire substrate. The sapphire substrate and the temporary substrate are bonded using preset bonding parameters. The first substrate surface of the sapphire substrate is patterned to obtain a patterned sapphire substrate; An epitaxial layer and a chip structure layer are sequentially fabricated on the patterned sapphire substrate to obtain an LED chip. The LED chip is fixed on a preset grinding stage, and an etching solution is introduced into the target through hole to etch the bonding layer between the temporary substrate and the sapphire substrate, so that the temporary substrate is detached from the sapphire substrate. The surface of the second substrate of the sapphire substrate is ground to control the finished thickness of the LED chip.

2. The method for preparing an LED chip according to claim 1, characterized in that, The temporary substrate is made of a high-melting-point inert material with a melting point greater than 1100°C.

3. The method for preparing an LED chip according to claim 1, characterized in that, The thickness of the temporary substrate is 400μm-1000μm.

4. The method for preparing an LED chip according to claim 1, characterized in that, The diameter of the target via is 100μm-1000μm, the spacing between the target vias is 2000μm-10000μm, and the area of ​​the target vias accounts for 1 / 5-1 / 3 of the area of ​​the temporary substrate.

5. The method for preparing an LED chip according to claim 1, characterized in that, The bonding layer is made of SiO2 material and has a thickness of 2μm-5μm.

6. The method for preparing an LED chip according to claim 1, characterized in that, The total thickness of the temporary substrate, the bonding layer, and the sapphire substrate is ≥550μm.

7. The method for preparing an LED chip according to claim 1, characterized in that, The step of stacking the sapphire substrate on the temporary substrate, with the bonding layer located between the temporary substrate and the sapphire substrate, and bonding the sapphire substrate and the temporary substrate using preset bonding parameters specifically includes: The bonding layer surface attached to the sapphire substrate is polished. The surface of the bonding layer is activated and cleaned using a cleaning solution, which is a mixture of H2SO4, H2O2 and H2O, with a volume ratio of H2SO4, H2O2 and H2O of 7:3:1-10:4:1, and the cleaning time is 8-20 min.

8. The method for preparing an LED chip according to claim 1, characterized in that, The steps of fixing the LED chip on a preset polishing stage and introducing an etching solution into the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby detaching the temporary substrate from the sapphire substrate, specifically include: A fusible adhesive medium is coated between the chip structure layer of the LED chip and / or a pre-set grinding stage; The chip structure layer of the LED chip is fixed on the polishing stage by means of the fusible adhesive medium; An etching solution is coated onto the temporary substrate and introduced along the target via to etch the bonding layer between the temporary substrate and the sapphire substrate, thereby causing the temporary substrate to detach from the sapphire substrate.

9. An LED chip, characterized in that, The LED chip is prepared using the preparation method described in any one of claims 1-8.

10. A temporary substrate obtained by detaching from an LED chip, characterized in that, The temporary substrate is used in the preparation of the LED chip in any one of the preparation methods of claims 1-8, and is removed after the LED chip is prepared so that it can be reused in the preparation process of the LED chip.

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