Micro light emitting diode array transfer method

Abstract

The application belongs to the technical field of micro light emitting diode display, and provides a micro light emitting diode array transfer method, which comprises the following steps: micro light emitting diode epitaxial structure preparation, P-type electrode layer array preparation, micro light emitting diode mesa array etching, substrate mesa array etching, first bonding layer and second bonding layer preparation, transfer substrate bonding, epitaxial substrate separation, buffer layer etching, N-type electrode layer preparation, third bonding layer preparation and transfer substrate cutting; the application forms a corrosion liquid channel in the epitaxial substrate by using a deep etching process, which is helpful to the rapid peeling of the epitaxial substrate and the micro light emitting diode mesa array, and improves the transfer efficiency of the micro light emitting diode.

Description

Technical Field

[0001] This invention relates to the field of micro light-emitting diode (LED) display technology, and in particular to a method for transferring a micro LED array. Background Technology

[0002] Miniature LED display technology features self-emissive pixels and boasts excellent color rendering performance, high resolution, superior reliability, low power consumption, fast response speed, and long lifespan. It has broad application prospects in virtual reality displays, augmented reality displays, consumer electronics, automotive displays, televisions, wearable displays, and large-screen displays. Miniature LED displays require the integration of millions of red, green, and blue primary color micro-LED chips, currently typically achieved using mass transfer methods.

[0003] However, the mass transfer process for micro LED displays is complex and has a low yield, which cannot meet the requirements of large-scale, high-consistency production, becoming the main technical bottleneck restricting the industrialization and commercial application of micro LED display technology. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for transferring a miniature light-emitting diode array, which solves the problems of complex mass transfer processes and low yield.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A method for transferring a miniature light-emitting diode array, comprising:

[0007] An epitaxial substrate is provided, and a buffer layer, an N-type conductive layer, a light-emitting layer, and a P-type conductive layer are sequentially fabricated on the epitaxial substrate to obtain a micro light-emitting diode epitaxial structure;

[0008] A P-type electrode layer array is fabricated on the surface of the P-type conductive layer of the micro light-emitting diode epitaxial structure; the P-type electrode layer array includes a plurality of P-type electrode layer sub-arrays spaced apart from each other; the P-type electrode layer sub-array includes a plurality of P-type electrode layer units spaced apart from each other.

[0009] The P-type conductive layer, the light-emitting layer, the N-type conductive layer, and the buffer layer are etched away from the spacer region of the P-type electrode layer unit to obtain a columnar micro-light-emitting diode mesa array; the columnar micro-light-emitting diode mesa array includes a plurality of micro-light-emitting diode mesa sub-arrays spaced apart from each other; the micro-light-emitting diode mesa sub-array includes a plurality of micro-light-emitting diode mesa units spaced apart from each other.

[0010] The surface of the epitaxial substrate in the spacer region of the micro-LED mesa unit is etched using a deep etching process to obtain a columnar substrate mesa array; the columnar substrate mesa array includes a plurality of spaced-apart substrate mesa sub-arrays; the substrate mesa sub-array includes a plurality of spaced-apart substrate mesa units; the spacer region of the substrate mesa sub-array forms a main etchant channel; the spacer region of the substrate mesa unit forms a secondary etchant channel.

[0011] A first bonding layer is prepared on the surface of the P-type electrode layer unit;

[0012] A transfer substrate is provided, and a second bonding layer is prepared on the transfer substrate;

[0013] The micro LED mesa array is bonded to the transfer substrate; the micro LED mesa array is connected to the transfer substrate in sequence through the P-type electrode layer array, the first bonding layer, and the second bonding layer;

[0014] The substrate mesa array is removed by etching with an etchant, and the micro light-emitting diode mesa array is transferred onto the transfer substrate.

[0015] The buffer layer is removed by etching, and an N-type electrode layer and a third bonding layer are sequentially prepared on the surface of the N-type conductive layer.

[0016] The transfer substrate is cut along the interval region of the micro LED mesa subarray to obtain the micro LED mesa subarray bonded to the transfer substrate.

[0017] Preferably, the epitaxial substrate is any one of a silicon substrate, a GaAs substrate, or an InP substrate.

[0018] Preferably, the buffer layer is a stack composed of one or more of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, and AlGaInP; the N-type conductive layer is a stack composed of one or more of the N-type conductive types AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, and AlGaInP. The light-emitting layer is a periodic multi-quantum-well structure composed of two or more of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, and AlGaInP; the P-type conductive layer is a stack composed of one or more of the P-type conductive types AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, and AlGaInP.

[0019] Preferably, the height of the substrate mesa array ranges from 0.01 μm to 1000 μm.

[0020] Preferably, the width of the spacing region of the P-type electrode layer subarray ranges from 0.01 mm to 10 mm; the size of the P-type electrode layer unit ranges from 0.1 μm to 1000 μm, and the spacing ranges from 0.1 μm to 1000 μm.

[0021] Preferably, the first bonding layer, the second bonding layer, and the third bonding layer are all stacks composed of one or more of the following: metal bonding materials, metal alloy solders, oxide films, polymer materials, photoresists, UV-curable adhesives, and paraffin wax.

[0022] Preferably, the etching solution is an anisotropic etching solution for the epitaxial substrate; the etching rate of the etching solution on the sidewalls of the substrate mesa array is greater than the etching rate on the surface of the substrate mesa array.

[0023] The present invention discloses the following technical effects:

[0024] This invention provides a method for transferring micro-LED arrays. By using a deep etching process to form etchant channels inside the epitaxial substrate and rapidly peeling the epitaxial substrate from the micro-LED mesa array, it solves the problems of low yield and high cost in mass transfer processes, enabling batch transfer of micro-LED arrays. By fabricating bonding layers on both end faces of the micro-LED array units, it solves the problem of poor compatibility of conventional mass transfer processes in different application scenarios, supports multiple transfers of micro-LED arrays, and has good process flexibility and scalability. By fabricating vertically structured micro-LED devices, the luminous efficiency of micro-LEDs is improved compared to the horizontally structured micro-LED devices used in conventional mass transfer processes. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the micro light-emitting diode array transfer process provided in an embodiment of the present invention;

[0027] Figure 2 This is a cross-sectional schematic diagram of the sample structure after the fabrication of the micro light-emitting diode epitaxial structure provided in an embodiment of the present invention;

[0028] Figure 3 This is a cross-sectional schematic diagram and a top view schematic diagram of the sample structure after the completion of the P-type electrode layer array fabrication, provided in an embodiment of the present invention.

[0029] Figure 4 A cross-sectional schematic diagram and a top view schematic diagram of the sample structure after etching of the micro light-emitting diode mesa array are provided for embodiments of the present invention;

[0030] Figure 5 This invention provides a cross-sectional schematic diagram and a top view schematic diagram of the sample structure after etching the substrate mesa array, as provided in an embodiment of the invention.

[0031] Figure 6 This is a cross-sectional schematic diagram of the sample structure after the preparation of the first bonding layer and the second bonding layer is completed, provided in an embodiment of the present invention.

[0032] Figure 7 This is a cross-sectional schematic diagram of the sample structure after the transfer substrate bonding is completed, provided in an embodiment of the present invention.

[0033] Figure 8This is a cross-sectional schematic diagram of the sample structure after epitaxial substrate separation provided in an embodiment of the present invention;

[0034] Figure 9 This is a cross-sectional schematic diagram of the sample structure after the preparation of the third bonding layer is completed, as provided in an embodiment of the present invention.

[0035] Figure 10 The images provided are a cross-sectional view and a top view of the sample structure after the transfer substrate has been cut, as provided in an embodiment of the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 101-Epipolar substrate, 102-Buffer layer, 103-N-type conductive layer, 104-Light emitting layer, 105-P-type conductive layer, 201-P-type electrode layer array, 202-P-type electrode layer sub-array, 301-Micro LED mesa array, 302-Micro LED mesa sub-array, 401-Substrate mesa array, 402-Substrate mesa sub-array, 403-Etching solution main channel, 404-Etching solution secondary channel, 501-First bonding layer, 502-Transfer substrate, 503-Second bonding layer, 601-N-type electrode layer, 602-Third bonding layer. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The purpose of this invention is to provide a method for transferring miniature light-emitting diode arrays, which solves the problems of complex mass transfer processes and low yield.

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Figure 1 This is a schematic diagram of the micro-light-emitting diode array transfer process provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the present invention provides a method for transferring a miniature light-emitting diode array, comprising:

[0042] Step 100: Provide an epitaxial substrate 101, and sequentially fabricate a buffer layer 102, an N-type conductive layer 103, a light-emitting layer 104, and a P-type conductive layer 105 on the epitaxial substrate 101 to obtain a micro light-emitting diode epitaxial structure;

[0043] Step 200: A P-type electrode layer array 201 is fabricated on the surface of the P-type conductive layer 105 of the micro light-emitting diode epitaxial structure; the P-type electrode layer array 201 includes a plurality of P-type electrode layer sub-arrays 202 spaced apart from each other; the P-type electrode layer sub-array 202 includes a plurality of P-type electrode layer units spaced apart from each other.

[0044] Step 300: Etch away the P-type conductive layer 105, the light-emitting layer 104, the N-type conductive layer 103, and the buffer layer 102 in the spacing region of the P-type electrode layer unit to obtain a columnar micro-light-emitting diode mesa array 301; the columnar micro-light-emitting diode mesa array 301 includes a plurality of micro-light-emitting diode mesa sub-arrays 302 spaced apart from each other; the micro-light-emitting diode mesa sub-array 302 includes a plurality of micro-light-emitting diode mesa units spaced apart from each other;

[0045] Step 400: The surface of the epitaxial substrate 101 in the spacing region of the micro light-emitting diode mesa unit is etched using a deep etching process to obtain a columnar substrate mesa array 401; the columnar substrate mesa array 401 includes a plurality of substrate mesa sub-arrays 402 spaced apart from each other; the substrate mesa sub-array 402 includes a plurality of substrate mesa units spaced apart from each other; the spacing region of the substrate mesa sub-array 402 forms a main etchant channel 403; the spacing region of the substrate mesa units forms a secondary etchant channel 404.

[0046] Step 500: Prepare a first bonding layer 501 on the surface of the P-type electrode layer unit;

[0047] Step 600: Provide a transfer substrate 502 and prepare a second bonding layer 503 on the transfer substrate 502;

[0048] Step 700: The micro LED mesa array 301 is bonded to the transfer substrate 502; the micro LED mesa array 301 is connected to the transfer substrate 502 in sequence through the P-type electrode layer array 201, the first bonding layer 501, and the second bonding layer 503.

[0049] Step 800: Remove the substrate mesa array 401 by etching with an etchant, and transfer the micro LED mesa array 301 onto the transfer substrate 502;

[0050] Step 900: Etch away the buffer layer 102, and sequentially prepare an N-type electrode layer 601 and a third bonding layer 602 on the surface of the N-type conductive layer 103;

[0051] Step 1000: Cut the transfer substrate 502 along the interval region of the micro light-emitting diode mesa subarray 302 to obtain the micro light-emitting diode mesa subarray 302 bonded to the transfer substrate 502.

[0052] Specifically, please refer to the attached diagram for a detailed explanation:

[0053] Figure 2 This is a cross-sectional schematic diagram of the sample structure after the fabrication of the micro-light-emitting diode epitaxial structure provided in an embodiment of the present invention, as shown below. Figure 2 As shown, an epitaxial substrate 101 is provided, and a buffer layer 102, an N-type conductive layer 103, a light-emitting layer 104, and a P-type conductive layer 105 are sequentially fabricated on the epitaxial substrate 101 to form a micro light-emitting diode epitaxial structure.

[0054] Figure 3 The cross-sectional and top views of the sample structure after the completion of the P-type electrode layer array 201 fabrication are provided in the embodiments of the present invention, as shown in the figure. Figure 3 As shown, a P-type electrode layer array 201 is fabricated on the surface of a micro light-emitting diode epitaxial structure; the P-type electrode layer array 201 includes several P-type electrode layer sub-arrays 202 spaced apart from each other;

[0055] Figure 4 The cross-sectional and top-view schematic diagrams of the sample structure after etching the micro-light-emitting diode mesa array 301 are provided for embodiments of the present invention, as shown in the following figures. Figure 4 As shown, the P-type conductive layer 105, light-emitting layer 104, N-type conductive layer 103, and buffer layer 102 of the spacer region of the P-type electrode layer array 201 are etched away to form a columnar micro-light-emitting diode mesa array 301; the micro-light-emitting diode mesa array 301 includes a plurality of micro-light-emitting diode mesa sub-arrays 302 spaced apart from each other.

[0056] Figure 5 The cross-sectional and top views of the sample structure after etching the substrate mesa array 401 are provided in the embodiments of the present invention, as shown in the figure. Figure 5 As shown, a deep etching process is used to etch the surface of the epitaxial substrate 101 of the spacing region of the micro light-emitting diode mesa array 301 unit to form a columnar substrate mesa array 401; the substrate mesa array 401 includes a plurality of substrate mesa sub-arrays 402 spaced apart from each other, the spacing region of the substrate mesa sub-arrays 402 forms the main etchant channel 403; the spacing region of the array unit inside the substrate mesa sub-arrays 402 forms the secondary etchant channel 404.

[0057] Figure 6 This is a cross-sectional schematic diagram of the sample structure after the preparation of the first bonding layer 501 and the second bonding layer 503, as provided in an embodiment of the present invention. Figure 6As shown, a first bonding layer 501 is prepared on the surface of a unit of a P-type electrode layer array 201; a transfer substrate 502 is provided, and a second bonding layer 503 is prepared on the transfer substrate 502;

[0058] Figure 7 This is a cross-sectional schematic diagram of the sample structure after bonding of the transfer substrate 502 according to an embodiment of the present invention, as shown below. Figure 7 As shown, a micro LED mesa array 301 is bonded to a transfer substrate 502; the micro LED mesa array 301 is connected to the transfer substrate 502 in sequence through a P-type electrode layer array 201, a first bonding layer 501, and a second bonding layer 503.

[0059] Figure 8 This is a cross-sectional schematic diagram of the sample structure after separation of the epitaxial substrate 101 provided in an embodiment of the present invention, as shown below. Figure 8 As shown, the substrate mesa array 401 is removed by etching with an etchant, so that the epitaxial substrate 101 is separated from the micro light-emitting diode mesa array 301, while the micro light-emitting diode mesa array 301 remains on the transfer substrate 502.

[0060] Figure 9 This is a cross-sectional schematic diagram of the sample structure after the preparation of the third bonding layer 602, as provided in an embodiment of the present invention. Figure 9 As shown, the buffer layer 102 in the unit of the micro light-emitting diode mesa array 301 is etched away, and the N-type electrode layer 601 and the third bonding layer 602 are sequentially prepared on the exposed N-type conductive layer 103 surface.

[0061] Figure 10 The cross-sectional and top views of the sample structure after the transfer substrate 502 is cut according to the embodiments of the present invention are shown below. Figure 10 As shown, the transfer substrate 502 is cut along the interval region of the sub-array to obtain the micro-light-emitting diode mesa array 301 bonded to the transfer substrate 502, thus completing the micro-light-emitting diode array transfer.

[0062] Optionally, the epitaxial substrate 101 is one of a silicon substrate, a GaAs substrate, or an InP substrate.

[0063] Preferably, the buffer layer 102 is a stack composed of one or more of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, and AlGaInP; the N-type conductive layer 103 is a stack composed of one or more of the N-type conductive types AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, and AlGaInP. The optical layer 104 is a periodic multi-quantum well structure composed of two or more of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, AlGaInP; the P-type conductive layer 105 is a stack composed of one or more of the P-type conductive types AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, InP, AlGaInP.

[0064] Optionally, the height of the substrate mesa array 401 is between 0.01 μm and 1000 μm.

[0065] Preferably, the width of the spacing region of the P-type electrode subarray 202 is between 0.01 mm and 10 mm; the size of the array unit inside the P-type electrode subarray 202 is between 0.1 μm and 1000 μm, and the spacing is between 0.1 μm and 1000 μm.

[0066] Optionally, the first bonding layer 501, the second bonding layer 503, and the third bonding layer 602 are stacks composed of one or more of the following: metal bonding materials, metal alloy solders, oxide films, polymer materials, photoresists, UV-curable adhesives, and paraffin wax.

[0067] Preferably, the etching solution is an anisotropic etching solution for the epitaxial substrate 101, and the etching rate of the etching solution on the sidewalls of the substrate mesa array 401 is greater than the etching rate on the substrate surface.

[0068] Specifically, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments, such as... Figures 2 to 10 As shown, the method for transferring a miniature light-emitting diode array includes the following steps:

[0069] S1 as Figure 2 As shown, a silicon substrate with a surface of (111) is provided (corresponding to epitaxial substrate 101).

[0070] S2 as Figure 2 As shown, using a metal-organic chemical vapor deposition (MOCVD) apparatus, a 200 nm thick AlN layer and a 300 nm thick Al layer were sequentially grown on the silicon substrate in S1. 0.25 Ga 0.75 N layers (corresponding to buffer layer 102).

[0071] S3 as Figure 2 As shown, Al was prepared in S2 using a metal-organic chemical vapor deposition apparatus. 0.25 Ga 0.75 An N-type GaN layer (corresponding to N-type conductive layer 103), a light-emitting layer 104, and a P-type GaN layer (corresponding to P-type conductive layer 105) with a thickness of 2 μm are sequentially grown on the N-layer to form a micro-light-emitting diode epitaxial structure. The light-emitting layer 104 in this step is a 7-period InGaN / GaN multiple quantum well structure with a period thickness of 17 nm and an emission wavelength of 460 nm. The thickness of the P-type GaN layer in this step is approximately 0.2 μm.

[0072] S4 Figure 3 As shown, in step S3, an ITO layer array with a thickness of 100 nm (corresponding to P-type electrode layer array 201) is deposited on the surface of the micro light-emitting diode epitaxial structure. The ITO layer array in this step includes 2×2 ITO layer sub-arrays (corresponding to P-type electrode layer sub-array 202), and the width of the spacing region of the ITO layer sub-array is 1 mm. Each ITO layer sub-array contains 100×100 ITO layer array units, and the diameter of the ITO layer array units is 5 μm and the spacing is 10 μm.

[0073] S5 Figure 4 As shown, the P-type GaN layer, light-emitting layer 104, N-type GaN layer, and Al layer in the spacing region of the ITO layer array cells in S4 are etched away. 0.25 Ga 0.75 The N-layer and AlN-layer form a columnar micro-light-emitting diode mesa array 301; the micro-light-emitting diode mesa array 301 includes a plurality of micro-light-emitting diode mesa sub-arrays 302 spaced apart from each other.

[0074] S6 Figure 5As shown, a deep silicon etching process is used to etch the silicon substrate surface of the spacer region of the micro light-emitting diode mesa array 301 unit in S5 to form a columnar silicon substrate mesa array (corresponding to substrate mesa array 401); the silicon substrate mesa array includes 2×2 spaced-apart silicon substrate mesa sub-arrays (corresponding to substrate mesa sub-array 402), the spacer region of the silicon substrate mesa sub-array forms the etchant main channel 403; the spacer region of the array unit inside the silicon substrate mesa sub-array forms the etchant secondary channel 404.

[0075] S7 Figure 6 As shown, a first SiO2 layer with a thickness of 100 nm (corresponding to the first bonding layer 501) is deposited on the surface of the ITO layer array unit in S4; a sapphire substrate (corresponding to the transfer substrate 502) is provided, and a second SiO2 layer with a thickness of 100 nm (corresponding to the second bonding layer 503) is deposited on the sapphire substrate.

[0076] S8 Figure 7 As shown, a low-temperature bonding process is used to bond the micro-light-emitting diode mesa array 301 onto the sapphire substrate (corresponding to the transfer substrate 502); the micro-light-emitting diode mesa array 301 is connected to the sapphire substrate in sequence through an ITO layer array (corresponding to the P-type electrode layer sub-array 202), a first SiO2 layer (corresponding to the first bonding layer 501), and a second SiO2 layer (corresponding to the second bonding layer 503).

[0077] S9 Figure 8 As shown, the silicon substrate mesa array is removed by etching with KOH solution, so that the silicon substrate (corresponding to the epitaxial substrate 101) is separated from the micro light-emitting diode mesa array 301, and the micro light-emitting diode mesa array 301 remains on the sapphire substrate (corresponding to the transfer substrate 502).

[0078] S10 Figure 9 As shown, etching removes the AlN layer and Al layer from the micro-LED mesa array 301 unit. 0.25 Ga 0.75 N-layer: On the surface of the exposed N-type GaN layer (corresponding to N-type conductive layer 103), a Ti / Al / Ni / Au metal stack with a total thickness of 0.3 μm (corresponding to N-type electrode layer 601) and an Au metal layer with a thickness of 1 μm (corresponding to the third bonding layer 602) are sequentially prepared.

[0079] S11 as Figure 10 As shown, the transfer substrate 502 is cut along the interval region of the sub-array to obtain the micro-light-emitting diode mesa array 301 bonded to the transfer substrate 502, thus completing the micro-light-emitting diode array transfer.

[0080] The beneficial effects of this invention are as follows:

[0081] (1) The present invention discloses a method for transferring a micro light-emitting diode array, which uses a deep etching process to form an etch channel inside the epitaxial substrate, which helps to quickly peel the epitaxial substrate from the micro light-emitting diode mesa array and improves the transfer efficiency of the micro light-emitting diode.

[0082] (2) The micro light-emitting diode array unit prepared based on the present invention has a bonding layer on both end faces, which facilitates the subsequent multiple transfer processes of the micro light-emitting diode array.

[0083] (3) The micro light-emitting diode array prepared based on the present invention is a vertical structure micro light-emitting diode device, which helps to improve the luminous efficiency of micro light-emitting diodes.

[0084] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0085] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for transferring a miniature light-emitting diode array, characterized in that, include: An epitaxial substrate is provided, and a buffer layer, an N-type conductive layer, a light-emitting layer, and a P-type conductive layer are sequentially fabricated on the epitaxial substrate to obtain a micro light-emitting diode epitaxial structure; A P-type electrode layer array is fabricated on the surface of the P-type conductive layer of the micro-light-emitting diode epitaxial structure; the P-type electrode layer array includes a plurality of P-type electrode layer sub-arrays spaced apart from each other; the P-type electrode layer sub-array includes a plurality of P-type electrode layer units spaced apart from each other; the width of the spacing region of the P-type electrode layer sub-array ranges from 0.01 mm to 10 mm; the size of the P-type electrode layer unit ranges from 0.1 μm to 1000 μm, and the spacing ranges from 0.1 μm to 1000 μm. The P-type conductive layer, the light-emitting layer, the N-type conductive layer, and the buffer layer are etched away from the spacer region of the P-type electrode layer unit to obtain a columnar micro-light-emitting diode mesa array; the columnar micro-light-emitting diode mesa array includes a plurality of micro-light-emitting diode mesa sub-arrays spaced apart from each other. The micro LED mesa subarray comprises several micro LED mesa units spaced apart from each other. The epitaxial substrate surface of the spacing region of the micro light-emitting diode mesa unit is etched using a deep etching process to obtain a columnar substrate mesa array. The columnar substrate mesa array comprises a plurality of spaced-apart substrate mesa sub-arrays; the substrate mesa sub-array comprises a plurality of spaced-apart substrate mesa units; the spacing regions of the substrate mesa sub-arrays form main channels for the etchant; the spacing regions of the substrate mesa units form secondary channels for the etchant; the height of the substrate mesa array ranges from 0.01 μm to 1000 μm. A first bonding layer is prepared on the surface of the P-type electrode layer unit; A transfer substrate is provided, and a second bonding layer is prepared on the transfer substrate; The micro LED mesa array is bonded onto the transfer substrate; The micro LED mesa array is connected to the transfer substrate in sequence through the P-type electrode layer array, the first bonding layer, and the second bonding layer; The substrate mesa array is removed by etching with an etchant, and the micro light-emitting diode mesa array is transferred onto the transfer substrate. The buffer layer is removed by etching, and an N-type electrode layer and a third bonding layer are sequentially prepared on the surface of the N-type conductive layer. The transfer substrate is cut along the interval region of the micro LED mesa subarray to obtain the micro LED mesa subarray bonded to the transfer substrate.

2. The method for transferring a micro-LED array according to claim 1, characterized in that, The epitaxial substrate is any one of silicon substrate, GaAs substrate, and InP substrate.

3. The method for transferring a micro-LED array according to claim 1, characterized in that, The buffer layer is a stack composed of one or more of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, AlGaInP; the N-type conductive layer is a stack composed of one or more of the N-type conductive types AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InGaP, InP, AlGaInP; the... The optical layer is a periodic multi-quantum well structure composed of two or more of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, AlGaInP; the P-type conductive layer is a stack composed of one or more of the P-type conductive types of AlN, AlGaN, GaN, InGaN, InN, AlGaInN, AlAs, AlGaAs, GaAs, InGaAs, InAs, AlGaInAs, AlP, AlGaP, GaP, InGaP, InP, InP, AlGaInP.

4. The method for transferring a micro-light-emitting diode array according to claim 1, characterized in that, The first bonding layer, the second bonding layer, and the third bonding layer are all stacks composed of one or more of the following: metal bonding materials, metal alloy solders, oxide films, polymer materials, photoresists, UV-curable adhesives, and paraffin wax.

5. The method for transferring a micro-LED array according to claim 1, characterized in that, The etching solution is an anisotropic etching solution for the epitaxial substrate; the etching rate of the etching solution on the sidewalls of the substrate mesa array is greater than the etching rate on the surface of the substrate mesa array.

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