Flip thin-film LED chip, and preparation method therefor

Abstract

Disclosed in the present application are a flip thin-film LED chip, and a preparation method therefor. The preparation method for a flip thin-film LED chip comprises: performing epitaxial growth on a silicon-based substrate to form an epitaxial structure, wherein the epitaxial structure comprises a first semiconductor layer, an active layer and a second semiconductor layer, which are sequentially stacked on the silicon-based substrate; on the basis of the epitaxial structure, forming a first electrode, which is electrically connected to the first semiconductor layer, and a second electrode, which is electrically connected to the second semiconductor layer; and removing the silicon-based substrate by means of chemical etching.

Description

A flip-chip thin-film LED chip and its preparation method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 28, 2023, with application number 202310944892.X and application name “A Flip-Chip Thin-Film LED Chip and Its Preparation Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of semiconductor devices, and in particular to a flip-chip thin-film LED chip and a preparation method thereof. Background Art

[0003] As a new generation of solid-state cold light sources, LEDs offer low energy consumption, long life, easy control, safety, and environmental friendliness. They are ideal energy-saving and environmentally friendly products suitable for a variety of lighting applications. To improve the luminous efficiency of LED chips, a flip-chip LED chip process has been developed to reduce electrode obstruction of the light-emitting surface.

[0004] Current flip-chip LED chips utilize the light-transmitting properties of sapphire substrates to direct the LED light outward from the sapphire substrate surface, creating a flip-chip structure. To create a flip-chip thin-film LED chip, a sapphire laser lift-off process is used to remove the substrate. Technical issues

[0005] However, the laser lift-off process is expensive, time-consuming, and has a low yield, making industrialization difficult. Technical Solutions

[0006] The present application provides a flip-chip thin-film LED chip and a preparation method thereof, which can prepare the flip-chip thin-film LED chip without using a laser lift-off process, thereby avoiding the problems of high cost, long time required and low yield caused by the laser lift-off process.

[0007] The present invention provides a method for preparing a flip-chip thin-film LED chip, comprising:

[0008] Performing epitaxial growth on a silicon-based substrate to form an epitaxial structure, wherein the epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence on the silicon-based substrate;

[0009] forming a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer based on the epitaxial structure;

[0010] Chemical etching is used to remove the silicon-based substrate.

[0011] In some embodiments, the method for preparing a flip-chip thin-film LED chip further comprises, before removing the silicon-based substrate by chemical etching:

[0012] A temporary fixing layer is provided, and the second semiconductor layer is bonded to the temporary fixing layer using a bonding process.

[0013] In some embodiments, the method for preparing a flip-chip thin-film LED chip further comprises, after removing the silicon-based substrate by chemical etching:

[0014] Providing a quantum dot white light conversion layer, and laminating the quantum dot white light conversion layer to a side of the first semiconductor layer away from the second semiconductor layer;

[0015] Remove the temporary fixing layer.

[0016] In some embodiments, the method for preparing a flip-chip thin-film LED chip further comprises, after removing the silicon-based substrate by chemical etching:

[0017] The surface of the first semiconductor layer is roughened.

[0018] In some embodiments, the method for preparing a flip-chip thin-film LED chip, wherein the second semiconductor layer is bonded to the temporary fixing layer using a bonding process, specifically includes:

[0019] A first organic adhesive layer is provided, and the second semiconductor layer is bonded to the temporary fixing layer through the first organic adhesive layer through a bonding process.

[0020] In some embodiments, a method for preparing a flip-chip thin-film LED chip, providing a quantum dot white light conversion layer, includes:

[0021] Sapphire etching by inductively coupled plasma;

[0022] Sapphire is etched with gallium nitride material to form a microporous structure, and white light conversion quantum dot material is spin-coated in the microporous structure by spin coating;

[0023] The quantum dot white light conversion layer is formed by depositing an insulating material or a protective colloid to protect the quantum dot material.

[0024] In some embodiments, the method for preparing a flip-chip thin-film LED chip, roughening the surface of the first semiconductor layer includes:

[0025] The surface of the first semiconductor is roughened by using an alkaline etching solution.

[0026] In some embodiments, a method for preparing a flip-chip thin-film LED chip, wherein the quantum dot white light conversion layer is bonded to a side of the first semiconductor layer away from the second semiconductor layer, comprises:

[0027] A second organic bonding layer is provided, and the quantum dot white light conversion layer and the first semiconductor layer are bonded via the second organic bonding layer.

[0028] In some embodiments of the method for preparing a flip-chip thin-film LED chip, the first organic adhesive layer is a thermosetting resin layer or a light-curing resin layer.

[0029] In some embodiments of the method for preparing a flip-chip thin-film LED chip, the first organic adhesive layer is a thermosetting resin layer or a light-curing resin layer.

[0030] In some embodiments, a method for preparing a flip-chip thin-film LED chip, wherein a first electrode electrically connected to a first semiconductor layer and a second electrode electrically connected to a second semiconductor layer are formed based on an epitaxial structure, comprises:

[0031] Etching the epitaxial structure to form a through groove, the through groove penetrating the active layer and the second semiconductor layer to expose the first semiconductor layer;

[0032] forming a metal reflective layer on a surface of the second semiconductor layer in ohmic contact with the second semiconductor layer;

[0033] forming an insulating layer covering the metal reflective layer and the through groove, and opening a through hole in the insulating layer to expose a portion of the metal reflective layer and the first semiconductor layer respectively;

[0034] A first electrode and a second electrode are formed on the insulating layer, wherein the first electrode is electrically connected to the first semiconductor layer, and the second electrode is electrically connected to the metal reflective layer.

[0035] In some embodiments of the method for preparing a flip-chip thin-film LED chip, the materials of the first semiconductor layer and the second semiconductor layer include gallium nitride.

[0036] In some embodiments of the method for preparing a flip-chip thin-film LED chip, the first semiconductor layer is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer.

[0037] In some embodiments of the method for preparing a flip-chip thin-film LED chip, the first electrode is an N electrode, and the second electrode is a P electrode.

[0038] The present application also provides a flip-chip thin-film LED chip, comprising:

[0039] An epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; the epitaxial layer has a through groove, which penetrates the active layer and the second semiconductor layer to expose the first semiconductor layer;

[0040] a metal reflective layer, the metal reflective layer being located on the second semiconductor layer and avoiding the through groove;

[0041] an insulating layer, wherein the metal reflective layer is located on the metal reflective layer and fills the through groove;

[0042] a first electrode, the first electrode being electrically connected to the first semiconductor layer;

[0043] The second electrode is electrically connected to the metal reflective layer.

[0044] In some embodiments of the flip-chip thin-film LED chip, the materials of the first semiconductor layer and the second semiconductor layer both include gallium nitride.

[0045] In some embodiments, the flip-chip thin-film LED chip further includes a quantum dot white light conversion layer, which is bonded to a side of the first semiconductor layer away from the second semiconductor layer via an organic bonding layer.

[0046] In some embodiments of the flip-chip film LED chip, the organic adhesive layer is a thermosetting resin layer or a light-curing resin layer.

[0047] In some embodiments of the flip-chip thin-film LED chip, the first semiconductor layer is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer.

[0048] In some embodiments of the flip-chip thin-film LED chip, the first electrode is an N electrode, and the second electrode is a P electrode. Beneficial effects

[0049] The present application provides a flip-chip thin-film LED chip and a preparation method thereof. The preparation method of the flip-chip thin-film LED chip forms an epitaxial structure by directly performing epitaxial growth on a silicon-based substrate, and then forms a first electrode and a second electrode based on the epitaxial structure; after the first electrode and the second electrode are set, chemical etching is used to remove the silicon-based substrate; in this process, the silicon-based substrate is directly removed by chemical etching, and the flip-chip thin-film LED chip can be prepared without the need for a laser lift-off process, thereby avoiding the problems of high cost, long time required and low yield caused by the laser lift-off process. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0051] FIG1 is a flow chart of a first method for preparing a flip-chip thin-film LED chip provided in an embodiment of the present application.

[0052] FIG2 is a schematic diagram of the structure of a flip-chip thin-film LED chip including an epitaxial structure and a silicon-based substrate provided in an embodiment of the present application.

[0053] FIG3 is a second flow chart of the method for preparing a flip-chip thin-film LED chip provided in an embodiment of the present application.

[0054] FIG4 is a schematic diagram of the structure of a flip-chip thin-film LED chip including a temporary fixing layer provided in an embodiment of the present application.

[0055] FIG5 is a third flow chart of the method for preparing a flip-chip thin-film LED chip provided in an embodiment of the present application.

[0056] FIG6 is a schematic diagram of the structure of a flip-chip thin-film LED chip after removing the substrate provided in an embodiment of the present application.

[0057] FIG7 is a schematic diagram of the structure of a flip-chip thin-film LED chip including a quantum dot white light conversion layer provided in an embodiment of the present application.

[0058] FIG8 is a flow chart of step 200 in the method for preparing a flip-chip thin-film LED chip provided in an embodiment of the present application.

[0059] FIG9 is a schematic diagram of a first structure of a flip-chip thin-film LED chip provided in an embodiment of the present application.

[0060] FIG10 is a schematic diagram of a second structure of a flip-chip thin-film LED chip provided in an embodiment of the present application.

[0061] Reference numerals: 10, silicon-based substrate; 11, first semiconductor layer; 12, active layer; 13, second semiconductor layer; 20, first electrode; 30, second electrode; 40, temporary fixing layer; 50, quantum dot white light conversion layer; 60, reflective layer; 70, insulating layer. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features indicated. The features specified as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0064] Referring to FIG. 1 , this embodiment provides a method for preparing a flip-chip thin-film LED chip, comprising:

[0065] 100. Performing epitaxial growth on a silicon-based substrate to form an epitaxial structure, wherein the epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the silicon-based substrate;

[0066] 200. Forming a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer based on the epitaxial structure;

[0067] 300. Remove the silicon-based substrate using chemical etching.

[0068] Please refer to FIG2 , which is a schematic diagram of the epitaxial structure and the flip-chip thin-film LED chip structure of the silicon-based substrate 10 provided in this embodiment. In this embodiment, epitaxial growth is performed directly on the silicon-based substrate 10 to form the epitaxial structure. The epitaxial structure includes a first semiconductor layer 11, an active layer 12, and a second semiconductor layer 13 stacked in sequence on the silicon-based substrate 10. A first electrode 20 and a second electrode 30 are then formed based on the epitaxial structure. After the first electrode 20 and the second electrode 30 are set, chemical etching is used to remove the silicon-based substrate 10. After removing the silicon-based substrate 10, the thickness of the LED chip can be reduced to facilitate the formation of a flip-chip thin-film LED chip. In this process, the silicon-based substrate 10 is directly removed by chemical etching, and the flip-chip thin-film LED chip can be prepared without the need for a laser lift-off process, thereby avoiding the high cost, long time required, and low yield problems of the laser lift-off process.

[0069] As an embodiment, chemical etching is used to remove the silicon-based substrate 10, specifically acidic chemical etching. For example, a mixed acid such as nitric acid, acetic acid, and hydrofluoric acid is used to etch away the silicon-based substrate 10 on which the epitaxial structure is grown. This effectively avoids the need for a laser lift-off process to remove the substrate, thereby avoiding the high cost, long time required, and low yield associated with the laser lift-off process.

[0070] Please refer to Figure 3. In some embodiments, before step 300, the following steps are further included: 310, providing a temporary fixing layer 40, and bonding the second semiconductor layer 13 to the temporary fixing layer 40 using a bonding process. As shown in Figure 4, Figure 4 is a schematic diagram of the flip-chip thin-film LED chip structure provided in this embodiment, including the temporary fixing layer 40. Since the epitaxial structure is obtained by epitaxial growth on the silicon-based substrate 10, and then the first electrode 20 and the second electrode 30 are formed based on the epitaxial structure, the thickness of the LED chip structure after the formation of the first electrode 20 and the second electrode 30 is relatively thin. Therefore, in this embodiment, in order to facilitate the subsequent removal of the silicon-based substrate 10, a temporary fixing layer 40 is bonded to the side away from the silicon-based substrate 10, that is, the side of the second semiconductor layer 13, through a bonding process. In this application, the provision of the temporary fixing layer 40 can increase the thickness of the current LED chip structure, so as to facilitate the subsequent removal of the silicon-based substrate.

[0071] Referring to FIG. 5 , in some embodiments, after step 300, the following steps are further included:

[0072] 400. Provide a quantum dot white light conversion layer, and laminate the quantum dot white light conversion layer to a side of the first semiconductor layer away from the second semiconductor layer;

[0073] 500. Remove the temporary fixing layer.

[0074] Please refer to Figures 6 and 7. Figure 6 is a schematic diagram of the structure of the flip-chip film LED chip after the substrate is removed, as provided in this embodiment; Figure 7 is a schematic diagram of the structure of the flip-chip film LED chip with the quantum dot white light conversion layer 50 attached, as provided in this embodiment. In this embodiment, after removing the silicon-based substrate 10, the quantum dot white light conversion layer 50 is attached to the first semiconductor layer 11. Then, based on the fact that the light emitted by the quantum dot white light conversion layer 50 is white light, a flip-chip film white light LED chip is formed. If a temporary fixing layer 40 is provided before removing the silicon-based substrate 10, then after forming the white light LED chip, the temporary fixing layer 40 is removed (as shown in Figure 7) to form the flip-chip film white light LED chip.

[0075] In some embodiments, after chemical etching is used to remove the silicon-based substrate 10, the surface of the first semiconductor layer 11 is roughened. Specifically, the first semiconductor layer 11 can be roughened using an alkaline etching solution such as sodium hydroxide or sodium carbonate to improve the light extraction efficiency of the first semiconductor layer 11.

[0076] In some embodiments, the step of bonding the second semiconductor layer 13 to the temporary fixing layer 40 using a bonding process specifically includes: providing a first organic adhesive layer, and bonding the second semiconductor layer 13 to the temporary fixing layer 40 through the first organic adhesive layer using a bonding process.

[0077] The first organic adhesive layer is a heat-curable resin layer or a light-curable resin layer. When the temporary fixing layer 40 needs to be removed later, the heat-curable resin layer or the light-curable resin layer can be used to remove the temporary fixing layer 40 by irradiating it with high temperature or ultraviolet light. Specifically, the first organic adhesive layer can include a material resistant to strong acid and alkali corrosion, such as epoxy resin or silicone resin.

[0078] In some embodiments, the step of laminating the quantum dot white light conversion layer 50 to the side of the first semiconductor layer 11 away from the second semiconductor layer 13 specifically includes providing a second organic adhesive layer, and passing the quantum dot white light conversion layer 50 and the first semiconductor layer 11 through the second organic adhesive layer. Similarly, the second organic adhesive layer in this embodiment can be a thermosetting resin layer or a light-curing resin layer. The quantum dot white light conversion layer 50 and the first semiconductor layer 11 are bonded through the second organic adhesive layer, thereby directly forming a flip-chip thin-film white light LED chip.

[0079] Compared to white light chips manufactured using a bracket packaging model, the thermal resistance of the lamp beads is higher, resulting in higher junction temperatures and lower luminous efficiency. Furthermore, the cost of the required quantum dot film, which is excited by blue light, is relatively high. Therefore, in this embodiment, a thin-film flip-chip white light LED chip is prepared by directly attaching a quantum dot white light conversion layer 50. This can reduce chip packaging costs and quantum dot film costs while improving luminous efficiency.

[0080] Referring to FIG. 8 , in some embodiments, step 200 specifically includes:

[0081] 210. Etching the epitaxial structure to form a through groove, the through groove penetrating the active layer and the second semiconductor layer to expose the first semiconductor layer;

[0082] 220. Forming a metal reflective layer on a surface of the second semiconductor layer in ohmic contact with the second semiconductor layer;

[0083] 230. Form an insulating layer covering the metal reflective layer and the through groove, and open a through hole in the insulating layer to expose a portion of the metal reflective layer and the first semiconductor layer respectively;

[0084] 240. Form a first electrode and a second electrode on the insulating layer, wherein the first electrode is electrically connected to the first semiconductor layer, and the second electrode is electrically connected to the metal reflective layer.

[0085] Please continue to refer to Figure 7. In this embodiment, a first semiconductor structure, an active layer 12, and a second semiconductor structure are sequentially grown on a silicon substrate to form an epitaxial structure. A through-groove is then etched based on the epitaxial structure to expose a portion of the first semiconductor layer 11. Specifically, the through-groove extends along the surface of the second semiconductor layer 13 to the first semiconductor layer 11, exposing the first semiconductor layer 11. Then, using a photolithography process, a metal reflective layer 60 is deposited on the surface of the second semiconductor layer 13 by metal sputtering or electron beam deposition, forming an ohmic contact with the second semiconductor layer 13. This metal reflective layer 60 avoids the through-groove. In this embodiment, the provision of the metal reflective layer 60 can improve light extraction.

[0086] Then, an insulating layer 70 is covered on the metal reflective layer. The insulating layer 70 is obtained by deposition, and the insulating layer 70 needs to cover the through groove. In order to facilitate the subsequent formation of the first electrode 20 and the second electrode 30, it is also necessary to open a through hole in the insulating layer 70 to expose the metal reflective layer and the first semiconductor layer respectively. The specific method of opening the through hole can be a chemical method. Afterwards, a layer of metal structure such as NiAlTiPtAu is deposited on the insulating layer 70 to form the first electrode 20 and the second electrode 30, wherein the first electrode 20 is electrically connected to the first semiconductor layer through the first through hole of the insulating layer 70, and the second electrode 30 is electrically connected to the metal reflective layer through the second through hole of the insulating layer 70. The first electrode 20 and the second electrode 30 are separated by the insulating layer 70; the first electrode 20 and the second electrode 30 are used to subsequently connect to the pads in the circuit board to form a conductive path.

[0087] As an embodiment, the material of the insulating layer 70 in this embodiment includes SiOx or SiNx.

[0088] As an embodiment, the materials of the first semiconductor layer 11 and the second semiconductor layer 13 include gallium nitride. The semiconductor layer formed of gallium nitride material is used to emit blue light in the future. The blue light is converted into white light after passing through the quantum dot white light conversion layer 50, so as to form a white light LED chip.

[0089] The first semiconductor layer 11 is an N-type semiconductor layer, and the second semiconductor layer 13 is a P-type semiconductor layer; the corresponding first electrode is an N-electrode, and the second electrode is a P-electrode.

[0090] In some embodiments, the step of providing quantum dot white-light conversion layer 50 includes: etching sapphire using inductively coupled plasma, then etching the sapphire using gallium nitride to form a microporous structure, and then spin-coating a white-light conversion quantum dot material within the microporous structure; and then protecting the quantum dot material by depositing an insulating material or protective colloid to form quantum dot white-light conversion layer 50. It should be noted that the formation of quantum dot white-light conversion layer 50 is well known and will not be further described here.

[0091] The present application also provides a flip-chip thin film LED chip, refer to FIG9, FIG9 is a schematic diagram of the first structure of the flip-chip thin film LED chip provided by the present application; the flip-chip thin film LED chip is prepared by the above-mentioned preparation method, and the flip-chip thin film LED chip includes an epitaxial structure, a metal reflective layer 60, an insulating layer 70, a first electrode 20 and a second electrode 30; wherein the epitaxial structure includes a first semiconductor layer 11, an active layer 12 and a second semiconductor layer 13 stacked in sequence; the epitaxial layer has a through groove, and the through groove penetrates the active layer 12 and the second semiconductor layer 13, so as to expose the first semiconductor layer 11; the metal reflective layer 60 is located on the second semiconductor layer 13 and avoids the through groove; the metal insulating layer 70 is located on the metal reflective layer 60 and fills the through groove; the first electrode 20 is electrically connected to the first semiconductor layer 11, and the second electrode 30 is electrically connected to the metal reflective layer 60; specifically, the first electrode 20 is located on the insulating layer 70 and passes through the first through hole on the insulating layer 70 to be electrically connected to the first semiconductor layer 11; the second electrode 30 is located on the insulating layer 70 and passes through the second through hole of the insulating layer 70 to be electrically connected to the metal reflective layer 60.

[0092] In some embodiments, the materials of the first semiconductor layer 11 and the second semiconductor layer 13 both include gallium nitride.

[0093] Please refer to Figure 10, which is a schematic diagram of the second structure of the flip-chip thin film LED chip provided by the present application. In some embodiments, the flip-chip thin film LED chip also includes a quantum dot white light conversion layer 50, and the quantum dot white light conversion layer 50 is bonded to the side of the first semiconductor layer 11 away from the second semiconductor layer 13 through an organic bonding layer, that is, in this embodiment, a flip-chip thin film white light LED chip can be directly obtained by bonding the quantum dot white light conversion layer 50. Compared with the white light chip made by the bracket packaging mode, the thermal resistance of the lamp bead is larger, which makes the chip junction temperature larger, and the light efficiency is lower; and the white light chip is formed by using blue light to excite the quantum dot film, and the cost of the required quantum dot film is higher. Therefore, in this embodiment, the thin film flip-chip white light LED chip is prepared by directly bonding the quantum dot white light conversion layer 50, which can reduce the chip packaging cost or reduce the quantum dot film cost and improve the light efficiency.

[0094] In some embodiments, the organic bonding layer is a thermosetting resin layer or a light-curing resin layer; specifically, the first organic bonding layer may include a strong acid and alkali corrosion-resistant material such as epoxy resin or silicone resin.

[0095] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0096] The above is a detailed introduction to the flip-chip thin-film LED chip provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a flip-chip thin-film LED chip, wherein: include: Performing epitaxial growth on a silicon-based substrate to form an epitaxial structure, wherein the epitaxial structure comprises a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the silicon-based substrate; forming a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer based on the epitaxial structure; The silicon-based substrate is removed by chemical etching.

2. The method for preparing a flip-chip thin-film LED chip according to claim 1, wherein: Before removing the silicon-based substrate by chemical etching, the method further comprises: A temporary fixing layer is provided, and the second semiconductor layer is bonded to the temporary fixing layer by a bonding process.

3. The method for preparing a flip-chip thin-film LED chip according to claim 2, wherein: After removing the silicon-based substrate by chemical etching, the method further comprises: Providing a quantum dot white light conversion layer, and laminating the quantum dot white light conversion layer to a side of the first semiconductor layer away from the second semiconductor layer; The temporary fixing layer is removed.

4. The method for preparing a flip-chip thin-film LED chip according to any one of claims 1 to 3, wherein: After removing the silicon-based substrate by chemical etching, the method further comprises: The surface of the first semiconductor layer is roughened.

5. The method for preparing a flip-chip thin-film LED chip according to claim 3, wherein: The step of bonding the second semiconductor layer to the temporary fixing layer using a bonding process specifically includes: A first organic bonding layer is provided, and the second semiconductor layer is bonded to the temporary fixing layer through the first organic bonding layer through a bonding process.

6. The method for preparing a flip-chip thin-film LED chip according to claim 3, wherein: The providing of a quantum dot white light conversion layer comprises: Sapphire etching by inductively coupled plasma; Sapphire is etched with gallium nitride to form a microporous structure, and white light is converted into The quantum dot material is spin-coated in the microporous structure; The quantum dot material is protected by depositing an insulating material or a protective colloid, thereby forming a quantum dot white light conversion layer.

7. The method for preparing a flip-chip thin-film LED chip according to claim 4, wherein: The roughening of the surface of the first semiconductor layer comprises: The surface of the first semiconductor is roughened by using an alkaline etching solution.

8. The method for preparing a flip-chip thin-film LED chip according to claim 5, wherein: The step of laminating the quantum dot white light conversion layer to a side of the first semiconductor layer away from the second semiconductor layer comprises: A second organic bonding layer is provided, and the quantum dot white light conversion layer and the first semiconductor layer are bonded together through the second organic bonding layer.

9. The method for preparing a flip-chip thin-film LED chip according to claim 5, wherein: The first organic adhesive layer is a thermosetting resin layer or a photocurable resin layer.

10. The method for preparing a flip-chip thin-film LED chip according to claim 8, wherein: The second organic adhesive layer is a thermosetting resin layer or a photocurable resin layer.

11. The method for preparing a flip-chip thin-film LED chip according to any one of claims 8 to 10, wherein: The forming of a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer based on the epitaxial structure comprises: Etching the epitaxial structure to form a through groove, wherein the through groove penetrates the active layer and the second semiconductor layer to expose the first semiconductor layer; forming a metal reflective layer on a surface of the second semiconductor layer in ohmic contact with the second semiconductor layer; forming an insulating layer covering the metal reflective layer and the through groove, and opening a through hole on the insulating layer to expose a portion of the metal reflective layer and the first semiconductor layer respectively; The first electrode and the second electrode are formed on the insulating layer, the first electrode is electrically connected to the first semiconductor layer, and the second electrode is electrically connected to the metal reflective layer.

12. The method for preparing a flip-chip thin-film LED chip according to claim 11, wherein: The materials of the first semiconductor layer and the second semiconductor layer include gallium nitride.

13. The method for preparing a flip-chip thin-film LED chip according to claim 12, wherein: The first semiconductor layer is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer.

14. The method for preparing a flip-chip thin-film LED chip according to claim 13, wherein: The first electrode is an N-electrode, and the second electrode is a P-electrode.

15. A flip-chip thin-film LED chip, wherein: include: An epitaxial structure, the epitaxial structure comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; The epitaxial layer has a through groove therein, and the through groove penetrates the active layer and the second semiconductor layer to expose the first semiconductor layer; a metal reflective layer, the metal reflective layer being located on the second semiconductor layer and avoiding the through groove; an insulating layer, the insulating layer being located on the metal reflective layer and filling the through groove; a first electrode, the first electrode being electrically connected to the first semiconductor layer; The second electrode is electrically connected to the metal reflective layer.

16. The flip-chip film LED chip according to claim 15, wherein: The materials of the first semiconductor layer and the second semiconductor layer both include gallium nitride.

17. The flip-chip film LED chip according to claim 16, wherein: The invention also includes a quantum dot white light conversion layer, wherein the quantum dot white light conversion layer is bonded to a side of the first semiconductor layer away from the second semiconductor layer through an organic bonding layer.

18. The flip-chip film LED chip according to claim 17, wherein: The organic adhesive layer is a thermosetting resin layer or a photocurable resin layer.

19. The flip-chip film LED chip according to claim 17, wherein: The first semiconductor layer is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer.

20. The flip-chip film LED chip according to claim 17, wherein: The first electrode is an N-electrode, and the second electrode is a P-electrode.

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