Formal LED chip and preparation method thereof

Abstract

The present invention proposes a vertical LED chip and a method for preparing the same. The method comprises: growing an undoped semiconductor layer and a second-type semiconductor layer on a sapphire substrate; depositing a transparent conductive layer on the second-type semiconductor layer, and using a laser to peel off the sapphire substrate; employing dry etching to etch from the undoped semiconductor layer to the transparent conductive layer; sequentially depositing a SiO2 layer, a reflective layer, a barrier layer, and a eutectic bonding layer on the undoped semiconductor layer; obtaining an aluminum nitride substrate, and depositing a eutectic bonding layer on the aluminum nitride substrate; and bonding the eutectic bonding layer on the SiO2 layer to the eutectic bonding layer on the aluminum nitride substrate. The method for preparing the vertical LED chip proposed in the present invention utilizes a substrate peeling process to release epitaxial lattice stress, effectively improving the internal quantum efficiency of the epitaxial layer. Furthermore, the use of an aluminum nitride substrate with excellent heat dissipation properties facilitates heat dissipation during chip operation, improving the chip's reliability under high current conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a front-mounted LED chip and a preparation method thereof. Background Art

[0002] Light Emitting Diode (LED) is known as the fourth generation lighting source or green light source. It has the characteristics of energy saving, environmental protection, long life and small size. It is widely used in various indication, display, decoration, backlight, general lighting and urban night view.

[0003] Currently, mainstream LED chips are categorized by structure into three types: face-mount, flip-chip, and vertical. Face-mount structures using insulating sapphire as substrates are the most common and widely adopted by the industry. Sapphire substrates are readily available, affordable, easy to clean and handle, highly stable at high temperatures, and can be grown stably in large sizes, making them the most widely used substrate material.

[0004] However, since the sapphire substrate itself is not conductive and has poor heat dissipation performance, it is difficult to meet the heat dissipation requirements of the product when manufacturing high-power LED chips due to its own high energy consumption, which greatly limits the production and application of high-power LED chips. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to propose a front-mounted LED chip and a preparation method thereof to solve the problem that the use of sapphire substrates to make LED chips is difficult to meet the requirements of the heat dissipation performance of high-power LED chips.

[0006] According to the present invention, a method for preparing a front-mounted LED chip comprises:

[0007] Obtain a sapphire substrate, and sequentially grow an undoped semiconductor layer, a first-type semiconductor layer, an active layer, and a second-type semiconductor layer on the sapphire substrate;

[0008] Then, a transparent conductive layer is deposited on the second-type semiconductor layer, and a laser is used to penetrate the interface between the sapphire substrate and the undoped semiconductor layer to remove the sapphire substrate;

[0009] Then, dry etching is performed to etch from the undoped semiconductor layer to the transparent conductive layer;

[0010] Then, a SiO2 layer, a reflective layer, a barrier layer and a eutectic bonding layer are sequentially deposited on the undoped semiconductor layer;

[0011] Next, an aluminum nitride substrate is obtained, and a eutectic bonding layer is deposited on the aluminum nitride substrate;

[0012] Then, the eutectic bonding layer on the SiO2 layer is bonded to the eutectic bonding layer on the aluminum nitride substrate.

[0013] Preferably, in the step of bonding the eutectic bonding layer on the SiO2 layer to the eutectic bonding layer on the aluminum nitride substrate:

[0014] The bonding temperature is 180-220°C and the bonding pressure is 0.1-0.3 MPa.

[0015] Preferably, after the step of using a laser to penetrate the interface between the sapphire substrate and the undoped semiconductor layer to remove the sapphire substrate, the step further includes:

[0016] Soak the structure after peeling off the sapphire substrate in a dilute hydrochloric acid solution for 10-15 minutes;

[0017] The chemical mechanical polishing technology is used to polish the surface of the undoped semiconductor layer exposed after the sapphire substrate is peeled off.

[0018] Preferably, after the step of depositing a transparent conductive layer on the second-type semiconductor layer, the method further comprises:

[0019] Depositing a SiO2 layer on the surface of the transparent conductive layer, and ultrasonically cleaning the SiO2 layer deposited on the transparent conductive layer with acetone for 10-15 minutes, and then cleaning and drying with deionized water;

[0020] Then soak in a mixture of H2SO4 and H2O2 for 18-23 minutes at a temperature of 110-130°C. After soaking, rinse with deionized water and dry.

[0021] Then soak in a mixed aqueous solution of NH4OH and H2O2 for 18-23 minutes at a soaking temperature of 65-75°C. After soaking, rinse with deionized water and dry.

[0022] Preferably, the step of soaking in a mixed aqueous solution of NH4OH and H2O2 for 18-23 minutes at a soaking temperature of 65-75°C, and washing with deionized water and drying after the soaking is completed further comprises:

[0023] Obtain a silicon wafer, clean the surface of the silicon wafer using a plasma cleaner, and then rinse with deionized water and dry;

[0024] The dried silicon wafer is bonded to the SiO2 layer deposited on the transparent conductive layer.

[0025] Preferably, after the step of bonding the eutectic bonding layer on the SiO2 layer to the eutectic bonding layer on the aluminum nitride substrate, the step further includes:

[0026] Grinding to remove the bonded silicon wafer and expose the SiO2 layer deposited on the transparent conductive layer;

[0027] Then, a BOE solution is used to etch away the SiO2 layer exposed on the chip surface, and the surface of the second-type semiconductor is dry-etched until the first-type semiconductor is exposed.

[0028] Then, a first electrode is evaporated on the surface of the first-type semiconductor, and a second electrode is evaporated on the surface of the transparent conductive layer;

[0029] Then, a passivation layer is deposited on the chip surface to protect the chip surface and sidewalls, and yellow light is used for patterning to expose the first electrode and the second electrode.

[0030] According to an embodiment of the present invention, a front-mounted LED chip comprises, from bottom to top, a substrate, a metal bonding stack, an undoped semiconductor layer, a first-type semiconductor layer, an active layer, a second-type semiconductor, and a transparent conductive layer, wherein:

[0031] The substrate is made of aluminum nitride material, and the thickness of the substrate is 200-500um.

[0032] Preferably, the metal bonding stack includes a reflective layer, a barrier layer and a eutectic bonding layer from top to bottom, the reflection direction of the reflective layer is toward one end of the active layer, the barrier layer is used to isolate the reflective layer and the eutectic bonding layer, and the eutectic bonding layer is used to bond the substrate.

[0033] Preferably, the reflective layer is made of at least one of Al and Ag materials, the barrier layer is made of at least one of Ti, Pt and Ni materials, and the eutectic bonding layer is made of Au and Sn or Pb and Sn materials.

[0034] Preferably, the upright LED chip has an inverted trapezoidal structure.

[0035] Compared with existing technologies, this method uses laser light to penetrate the interface between the sapphire substrate and the undoped semiconductor layer, causing the sapphire substrate to fall off and releasing epitaxial lattice stress, thereby improving the internal quantum efficiency of the epitaxial layer. Simultaneously, by sequentially depositing a SiO2 layer, a reflective layer, a barrier layer, and a eutectic bonding layer on the undoped semiconductor layer, and then depositing a eutectic bonding layer on the aluminum nitride substrate, the aluminum nitride substrate is effectively bonded to the undoped semiconductor layer. This replaces the sapphire substrate of the upright LED chip with an aluminum nitride substrate, significantly improving heat dissipation during operation of the high-power upright LED, reducing the device's thermal resistance during operation, increasing the internal recombination efficiency of the epitaxial layer, and thus improving the luminous efficiency to ensure the operational reliability of the high-power LED chip. This solves the problem of using sapphire substrates to manufacture LED chips, which often makes it difficult to meet the heat dissipation performance requirements of high-power LED chips. Furthermore, by sequentially depositing a metal bonding stack of reflective layers, barrier layers, and eutectic bonding layers, the metal reflective layer and silicon oxide at the bonding layer interface form a full-range reflector structure, effectively improving the overall reflectivity and further enhancing the chip's brightness.

[0036] Additional aspects and advantages of the present invention will be set forth in part in the following description and, in part, will be obvious from the following description, or may be learned through embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic structural diagram of a front-mounted LED chip proposed in the first embodiment of the present invention;

[0038] Figure 2 This is a flow chart of a method for preparing a face-mounted LED chip according to a second embodiment of the present invention.

[0039] Description of main component symbols:

[0040] substrate 10 Eutectic bonding layer 20 reflective layer 30 Undoped semiconductor layer 40 First type semiconductor layer 50 active layer 60 Second type semiconductor layer 70 Transparent conductive layer 80 First electrode 90 Second electrode 100

[0041] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0042] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0043] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] Example 1

[0046] See also Figure 1 , which is a schematic structural diagram of a front-mounted LED chip in a first embodiment of the present invention, includes, from bottom to top, a substrate 10, a metal bonding stack, an undoped semiconductor layer 40, a first-type semiconductor layer 50, an active layer 60, a second-type semiconductor 70, and a transparent conductive layer 80, wherein:

[0047] The substrate is made of aluminum nitride and has a thickness of 200-500 μm. In this embodiment, although a thicker substrate can further improve heat dissipation performance, it will reduce the compactness of the front-mounted LED chip and increase its manufacturing cost. If it is too thin, it will affect the heat dissipation performance. Therefore, the thickness of the substrate is between 200-500 μm, for example, 200 μm, 300 μm, 500 μm, etc. By replacing the aluminum nitride substrate with a sapphire substrate, which has better thermal conductivity than the sapphire substrate, the heat dissipation of the chip during operation is improved, thereby improving the chip's reliability under high current.

[0048] Furthermore, the metal bonding stack includes, from top to bottom, a reflective layer 30, a barrier layer and a eutectic bonding layer 20. The reflection direction of the reflective layer is toward one end of the active layer. The barrier layer is used to isolate the reflective layer and the eutectic bonding layer. The eutectic bonding layer is used to bond the substrate, and the reflective layer is made of at least one of Al and Ag materials, such as Ag. Since Ag or Al has high reflectivity in the visible light band, the reflectivity of light emitted from the active area to one side of the substrate is effectively improved. The barrier layer is made of at least one of Ti, Pt, and Ni materials, such as a mixed metal of Ti and Ni or Pt metal. The eutectic bonding layer is made of two materials, Au and Sn or Pb and Sn. The use of the eutectic bonding layer is beneficial to substrate packaging.

[0049] It should be noted that the upright LED chip in this embodiment has an inverted trapezoidal structure, that is, it is narrow at the bottom and wide at the inside, which can improve the light-emitting efficiency of the product by increasing the light-emitting area.

[0050] Example 2

[0051] See also Figure 2 , which is a flow chart of a method for preparing a front-mounted LED chip in a second embodiment of the present invention, is used to prepare the front-mounted LED chip in the first embodiment. The method specifically includes steps S01 to S06, wherein:

[0052] Step S01: obtaining a sapphire substrate, and sequentially growing an undoped semiconductor layer, a first-type semiconductor layer, an active layer, and a second-type semiconductor layer on the sapphire substrate;

[0053] Step S02: depositing a transparent conductive layer on the second-type semiconductor layer, and using a laser to penetrate the interface between the sapphire substrate and the undoped semiconductor layer to remove the sapphire substrate;

[0054] Step S03: dry etching is then performed to etch from the undoped semiconductor layer to the transparent conductive layer;

[0055] Step S04: then sequentially depositing a SiO2 layer, a reflective layer, a barrier layer, and a eutectic bonding layer on the undoped semiconductor layer;

[0056] Step S05: obtaining an aluminum nitride substrate and depositing a eutectic bonding layer on the aluminum nitride substrate;

[0057] Step S06: Then, the eutectic bonding layer on the SiO2 layer is bonded to the eutectic bonding layer on the aluminum nitride substrate.

[0058] Among them, after the sapphire substrate is peeled off by laser, in order to achieve the flatness of the undoped semiconductor layer, the structure after the sapphire substrate is peeled off needs to be immersed in a dilute hydrochloric acid solution for 10-15 minutes; and the surface of the undoped semiconductor layer exposed after the sapphire substrate is peeled off is polished using chemical mechanical polishing technology.

[0059] It should be noted that, since the epitaxial layer is relatively thin, peeling off the sapphire substrate will cause the epitaxial layer to lack a carrier and affect the subsequent manufacturing process. Based on this, before peeling off the sapphire substrate, a SiO2 layer will be deposited on the surface of the transparent conductive layer, and the SiO2 layer deposited on the transparent conductive layer will be ultrasonically cleaned with acetone for 10-15 minutes, and then washed and dried with deionized water; then immersed in a mixed solution of H2SO4 and H2O2 for 18-23 minutes at a soaking temperature of 110-130°C, and then washed and dried with deionized water; then Soak in a mixed aqueous solution of NH4OH and H2O2 for 18-23 minutes at a soaking temperature of 65-75°C. After soaking, wash with deionized water and dry. Through the above soaking, washing and drying, the dirt and metal ion residues on the SiO2 layer are removed. After the surface treatment of the SiO2 layer, a silicon wafer is obtained, and the surface of the silicon wafer is cleaned with a plasma cleaner, and then rinsed with deionized water and dried. The dried silicon wafer is then bonded to the SiO2 layer deposited on the transparent conductive layer, thereby providing a carrier for the epitaxial layer.

[0060] Furthermore, after the sapphire substrate is peeled off and the surface of the undoped semiconductor layer is flattened, the bonded silicon wafer is removed by grinding to expose the SiO2 layer deposited on the transparent conductive layer; then the SiO2 layer exposed on the chip surface is corroded and removed using a BOE solution, and the surface of the second-type semiconductor is dry-etched until the first-type semiconductor is exposed; then the first electrode is evaporated on the surface of the first-type semiconductor, and the second electrode is evaporated on the surface of the transparent conductive layer; then a passivation layer is deposited on the chip surface to protect the chip surface and side walls, and yellow light patterning is used to expose the first electrode 90 and the second electrode 100, thereby producing the final upright LED chip.

[0061] For purposes of illustration and not limitation, specific production examples are as follows:

[0062] An LED epitaxial wafer with a sapphire substrate is provided, which comprises a sapphire substrate, an undoped semiconductor layer, a first-type semiconductor layer, an active layer, and a second-type semiconductor layer sequentially grown on the sapphire, and the surface of the epitaxial wafer is cleaned.

[0063] A transparent conductive layer is deposited on the surface of the second type semiconductor with a thickness of 600-1000 angstroms.

[0064] A silicon dioxide layer with a thickness of 50-100 nm is deposited on the surface of the second-type semiconductor of the epitaxial wafer using plasma enhanced chemical deposition.

[0065] The epitaxial wafer with a silicon dioxide layer deposited on the surface of the second-type semiconductor is ultrasonically cleaned with acetone for 10-15 minutes and then cleaned and dried with deionized water.

[0066] Then, the epitaxial wafer with a silicon dioxide layer deposited on the surface of the obtained second-type semiconductor is immersed in a solution of H2SO4 and H2O2 in a ratio of 2:1 for 18-23 minutes, with the temperature controlled at 110-130°C. After the immersion is completed, it is washed with deionized water and dried.

[0067] The epitaxial wafer with a silicon dioxide layer deposited on the surface of the second-type semiconductor obtained in the second step is immersed in a solution of NH4OH:H2O2:H2O with a ratio of 1:1:5 for 18-23 minutes, with the temperature controlled at 65-75°C. After the immersion is completed, it is washed with deionized water and dried.

[0068] A silicon wafer is provided, its surface treated with O2 plasma, rinsed with deionized water, and dried. The silicon wafer is then bonded to an epitaxial wafer having a silicon dioxide layer deposited on the surface of a second semiconductor at a bonding temperature of 180-220°C and a bonding pressure of 0.1-0.3 MPa.

[0069] A laser with a wavelength of 266nm and an energy density of 325-380mJ / cm2 is used to penetrate the sapphire substrate and focus on the sapphire substrate and the undoped semiconductor layer, decomposing a certain thickness of GaN material at the interface between the two, causing the sapphire substrate to fall off and expose the undoped semiconductor layer.

[0070] The obtained structure after substrate stripping is placed in a 20% dilute hydrochloric acid solution and soaked for 10-15 minutes to remove Ga metal adsorbed on the surface of the structure due to the decomposition of GaN caused by laser stripping.

[0071] Chemical mechanical polishing (CMP) is used to planarize the surface of the undoped semiconductor layer exposed after stripping.

[0072] Use dry etching to etch from the undoped semiconductor layer to the transparent conductive layer deposited in the second step to obtain multiple independent light-emitting areas.

[0073] Silicon dioxide is deposited on the surface of the planarized undoped semiconductor layer using a plasma enhanced chemical deposition method.

[0074] Based on the silicon dioxide deposited in the previous step, a metal bonding stack is deposited on the silicon dioxide.

[0075] An aluminum nitride substrate is provided, and a eutectic bonding layer is deposited on the substrate.

[0076] Bond the LED layers that have been bonded to the silicon wafer to the substrate at a bonding temperature of 180-220°C and a bonding pressure of 0.1-0.3 MPa.

[0077] The bonded silicon wafer is removed by grinding to expose the silicon dioxide layer underneath the silicon wafer.

[0078] The silicon dioxide residue on the surface of the second epitaxial layer is cleaned with BOE solution to obtain a substrate having an epitaxial light-emitting area of ​​an LED chip on the surface.

[0079] Use dry etching to etch a mesa on the surface of the second-type semiconductor until the first-type semiconductor is exposed, with an etching depth of 1-1.3 μm.

[0080] A first electrode and a second electrode are evaporated on the surface of the first-type semiconductor and the surface of the transparent conductive layer respectively.

[0081] A passivation layer is deposited on the chip surface to protect the chip surface and sidewalls, and yellow light is used to pattern and expose the first electrode and the second electrode, thereby producing the final upright LED chip.

[0082] Please refer to Table 1, which shows the performance data of the upright LED chip obtained according to the above steps, as shown in the following table:

[0083]

[0084] As shown in Table 1, by replacing the sapphire substrate with an aluminum nitride substrate that is easy to dissipate heat through substrate stripping and bonding processes, and setting a reflective layer structure under the active layer, the brightness of the resulting upright LED chip is increased by 3.73% compared to the traditional LED chip, which effectively improves the chip's brightness.

[0085] In summary, according to the above-mentioned method for preparing a face-mounted LED chip, a laser is used to penetrate the interface between the sapphire substrate and the undoped semiconductor layer to cause the sapphire substrate to fall off, thereby releasing the epitaxial lattice stress and improving the internal quantum efficiency of the epitaxial layer. Simultaneously, a SiO2 layer, a reflective layer, a barrier layer, and a eutectic bonding layer are sequentially deposited on the undoped semiconductor layer, and a eutectic bonding layer is deposited on the aluminum nitride substrate to effectively bond the aluminum nitride substrate to the undoped semiconductor layer. This replaces the sapphire substrate of the face-mounted LED chip with an aluminum nitride substrate, significantly improving the heat dissipation of the high-power face-mounted LED during operation, reducing the device's thermal resistance during operation, increasing the internal recombination efficiency of the epitaxial layer, and thereby improving the luminous efficiency, ensuring the operational reliability of the high-power LED chip. This solves the problem of using sapphire substrates to manufacture LED chips, which often makes it difficult to meet the heat dissipation performance requirements of high-power LED chips. Furthermore, by sequentially depositing a metal bonding stack of the reflective layer, the barrier layer, and the eutectic bonding layer, the metal reflective layer and the silicon oxide at the bonding layer interface form a full-range reflector structure, effectively improving the overall reflectivity and further enhancing the chip brightness.

[0086] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0087] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a front-mounted LED chip, characterized in that: The method comprises: Obtain a sapphire substrate, and sequentially grow an undoped semiconductor layer, a first-type semiconductor layer, an active layer, and a second-type semiconductor layer on the sapphire substrate; Then, a transparent conductive layer is deposited on the second-type semiconductor layer, and a laser is used to penetrate the interface between the sapphire substrate and the undoped semiconductor layer to remove the sapphire substrate, including: Depositing a transparent conductive layer on the second-type semiconductor layer, and depositing a SiO2 layer on the surface of the transparent conductive layer, Providing a silicon wafer, bonding the silicon wafer to a SiO2 layer deposited on a transparent conductive layer, Using laser to penetrate the interface between the sapphire substrate and the undoped semiconductor layer to remove the sapphire substrate, Soak the structure after peeling off the sapphire substrate in a dilute hydrochloric acid solution for 10-15 minutes. The surface of the undoped semiconductor layer exposed after the sapphire substrate is peeled off is polished using chemical mechanical polishing technology; Then, dry etching is performed to etch from the undoped semiconductor layer to the transparent conductive layer; Then, a SiO2 layer, a reflective layer, a barrier layer and a eutectic bonding layer are sequentially deposited on the undoped semiconductor layer; Next, an aluminum nitride substrate is obtained, and a eutectic bonding layer is deposited on the aluminum nitride substrate; Then, the eutectic bonding layer on the SiO2 layer is bonded to the eutectic bonding layer on the aluminum nitride substrate; Grinding to remove the bonded silicon wafer and expose the SiO2 layer deposited on the transparent conductive layer; Then, a BOE solution is used to etch away the SiO2 layer exposed on the chip surface, and the surface of the second-type semiconductor is dry-etched until the first-type semiconductor is exposed. Then, a first electrode is evaporated on the surface of the first-type semiconductor, and a second electrode is evaporated on the surface of the transparent conductive layer; Then, a passivation layer is deposited on the chip surface to protect the chip surface and sidewalls, and yellow light is used for patterning to expose the first electrode and the second electrode.

2. The method for preparing a front-mounted LED chip according to claim 1, wherein: In the step of bonding the eutectic bonding layer on the SiO2 layer to the eutectic bonding layer on the aluminum nitride substrate: The bonding temperature is 180-220°C and the bonding pressure is 0.1-0.3 MPa.

3. The method for preparing a front-mounted LED chip according to claim 1, wherein: After depositing a transparent conductive layer on the second-type semiconductor layer and depositing a SiO2 layer on the surface of the transparent conductive layer, the method further comprises: The SiO2 layer deposited on the transparent conductive layer is ultrasonically cleaned with acetone for 10-15 minutes, and then cleaned and dried with deionized water; Then soak in a mixture of H2SO4 and H2O2 for 18-23 minutes at a temperature of 110-130°C. After soaking, rinse with deionized water and dry. Then soak in a mixed aqueous solution of NH4OH and H2O2 for 18-23 minutes at a soaking temperature of 65-75°C. After soaking, rinse with deionized water and dry.

4. The method for preparing a front-mounted LED chip according to claim 1, wherein: Providing a silicon wafer, and bonding the silicon wafer to a SiO2 layer deposited on a transparent conductive layer, specifically comprising: Obtain a silicon wafer, clean the surface of the silicon wafer using a plasma cleaner, and then rinse with deionized water and dry; The dried silicon wafer is bonded to the SiO2 layer deposited on the transparent conductive layer.

5. A front-mounted LED chip, characterized in that: The upright LED chip is prepared by the method for preparing an upright LED chip according to any one of claims 1 to 4, and the upright LED chip comprises, from bottom to top, a substrate, a metal bonding stack, an undoped semiconductor layer, a first-type semiconductor layer, an active layer, a second-type semiconductor, and a transparent conductive layer, wherein: The substrate is made of aluminum nitride material, and the thickness of the substrate is 200-500um.

6. The upright LED chip according to claim 5, characterized in that: The metal bonding stack includes a reflective layer, a barrier layer and a eutectic bonding layer from top to bottom, wherein the reflection direction of the reflective layer is toward one end of the active layer, the barrier layer is used to isolate the reflective layer and the eutectic bonding layer, and the eutectic bonding layer is used to bond the substrate.

7. The upright LED chip according to claim 6, characterized in that: The reflective layer is made of at least one of Al and Ag materials, the barrier layer is made of at least one of Ti, Pt and Ni materials, and the eutectic bonding layer is made of Au and Sn or Pb and Sn materials.

8. The upright LED chip according to claim 7, characterized in that: The upright LED chip has an inverted trapezoidal structure.

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