Preparation method of micro light emitting diode display device and electronic device

Abstract

The present application provides a method for preparing a micro-LED display device and an electronic device, the method comprising providing a semiconductor substrate; forming a plurality of first driving wafers and a plurality of second driving wafers on the semiconductor substrate, each of the first driving wafers and the second driving wafer comprising a driving circuit for driving a micro-LED chip; forming an interconnection circuit layer on the plurality of first driving wafers and the plurality of second driving wafers; forming a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads on the interconnection circuit layer; forming a flip-chip micro-LED chip on each adjacent first micro-LED chip pad and a second micro-LED chip pad, each micro-LED chip being signal-connected to a first driving wafer and a second driving wafer. The present application is conducive to improving the yield of the micro-LED display device.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a method for preparing a micro light emitting diode display device and an electronic device. Background Art

[0002] In recent years, with the improvement of sub-millimeter light-emitting diode (Mini LED) display technology and the reduction of costs, its penetration rate has continued to increase. Sub-millimeter light-emitting diode display technology has the advantages of surface light source, high brightness, high contrast, and long life. The main terminal product is LED display. Thanks to the gradual increase in the penetration rate of LED small pitch and the reduction in the cost of LED display, sub-millimeter light-emitting diode display is gradually replacing LCD, projection and other products in application scenarios such as conference rooms. However, from the perspective of the industry's technological development, sub-millimeter light-emitting diodes are only a transitional product for micro light-emitting diodes (Micro LED). Micro light-emitting diode display technology has greater advantages in brightness, resolution, contrast, energy consumption, service life, response speed and thermal stability.

[0003] In the related art, micro-LED display devices are mainly prepared by mass transfer method, and the general process is: the micro-LED chip is grabbed from the first substrate, and then transferred to the second substrate with a driving circuit, and assembled into a two-dimensional periodic array.

[0004] However, the yield rate of the micro light emitting diode display device using the related art solution is low. Summary of the invention

[0005] The exemplary embodiments of the present application provide a method for manufacturing a micro-LED display device and an electronic device, which are beneficial to improving the yield of the micro-LED display device.

[0006] In one aspect, the present application provides a method for preparing a micro light emitting diode display device, comprising:

[0007] providing a semiconductor substrate;

[0008] Forming a plurality of first driving wafers and a plurality of second driving wafers on the semiconductor substrate, each of the first driving wafer and the second driving wafer comprising a driving circuit for driving a micro light emitting diode chip;

[0009] forming an interconnection circuit layer on the plurality of the first driving wafers and the plurality of the second driving wafers;

[0010] forming a plurality of first micro light emitting diode chip pads and a plurality of second micro light emitting diode chip pads on the interconnection circuit layer;

[0011] A flip-chip micro LED chip is formed on each adjacent first micro LED chip pad and second micro LED chip pad, and each of the micro LED chips is signal-connected to one of the first driving wafers and one of the second driving wafers.

[0012] The present application directly prepares a first driving wafer, a second driving wafer, an interconnection circuit layer, a first micro-LED chip pad and a second micro-LED chip pad on a semiconductor substrate, so that the micro-LED chip can be directly prepared on the first micro-LED chip pad and the second micro-LED chip pad without the need for mass transfer of the micro-LED chips, which is beneficial to improving the yield of the micro-LED display device.

[0013] In some embodiments of the present application, the interconnection circuit layer includes a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, a third insulating layer and a third metal layer which are stacked, and the step of forming the interconnection circuit layer on the plurality of the first driving wafers and the plurality of the second driving wafers includes:

[0014] Forming a first insulating layer by evaporation on the plurality of first driving wafers and the plurality of second driving wafers, removing a portion of the first insulating layer by etching, and forming a plurality of first via holes in the first insulating layer;

[0015] Forming a first copper-clad layer by evaporation on the first insulating layer, and forming a first metal layer through a patterning process so that the first copper-clad layer is connected to the first driving wafer or the second driving wafer through the first via hole;

[0016] Forming a second insulating layer by evaporating on the first metal layer, removing a portion of the second insulating layer by etching, and forming a plurality of second via holes on the second insulating layer;

[0017] Forming a second copper-clad layer by evaporation on the second insulating layer, and forming a second metal layer through a patterning process on the first copper-clad layer;

[0018] Forming a third insulating layer by evaporating on the second metal layer, removing a portion of the third insulating layer by etching, and forming a plurality of third via holes and a plurality of fourth via holes on the third insulating layer, wherein the plurality of fourth via holes correspond one to one to the plurality of second via holes;

[0019] A third copper clad layer is formed by vapor deposition on the third insulating layer, and a third metal layer is formed by a patterning process. The third metal layer is connected to the second metal layer through the third via hole, and the third metal layer is connected to the first metal layer through the fourth via hole and the second via hole.

[0020] The present application utilizes semiconductor technology to sequentially form interconnection circuit layers on a semiconductor substrate, which is beneficial to improving the accuracy of the interconnection circuit layers, and further beneficial to improving the yield of the micro-LED display device.

[0021] In some embodiments of the present application, the step of forming a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads on the interconnection circuit layer includes:

[0022] forming a fourth insulating layer by evaporating on the third metal layer, removing a portion of the fourth insulating layer by etching, and forming a plurality of fifth via holes on the first insulating layer;

[0023] A conductive layer is formed by vapor deposition on the fourth insulating layer, and a portion of the conductive layer is removed by etching to form a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads, wherein the first micro-LED chip pads are connected to the third metal layer through the fifth via holes, and the height of the second micro-LED chip pads is greater than the height of the first micro-LED chip pads.

[0024] The present application forms a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads on an interconnect circuit layer through a semiconductor process, thereby providing a basis for the preparation of micro-LED chips and facilitating improving the yield of micro-LED display devices.

[0025] In some embodiments of the present application, the step of forming a flip-chip micro LED chip on each adjacent first micro LED chip pad and second micro LED chip pad comprises:

[0026] Depositing a protection layer on the fourth insulating layer so that the protection layer fills between each adjacent first micro-LED chip pad and each adjacent second micro-LED chip pad;

[0027] A Bragg reflection layer is formed on the protective layer and the adjacent first micro-LED chip pad, so that the Bragg reflection layer covers the side of the second micro-LED chip pad facing the first micro-LED chip pad, a first through hole is further formed in the Bragg reflection layer, and the first micro-LED chip pad is partially located in the first through hole, so that the Bragg reflection layer and the first micro-LED chip pad form a first groove;

[0028] forming a transparent conductive layer on the Bragg reflective layer, wherein a second groove is formed on a side of the transparent conductive layer away from the first groove;

[0029] depositing a barrier layer in the second groove;

[0030] Forming a P-type semiconductor layer on the transparent conductive layer and the barrier layer, wherein the P-type semiconductor layer is connected to the first micro-LED chip pad;

[0031] forming a light emitting layer on the P-type semiconductor layer;

[0032] An N-type semiconductor layer is formed on the light emitting layer, and the N-type semiconductor layer is connected to the second micro light emitting diode chip pad.

[0033] The present application directly manufactures the micro-LED chip on the first micro-LED chip pad and the second micro-LED chip pad, thereby eliminating the step of transferring the micro-LED chip, which is beneficial to reducing the process difficulty.

[0034] In some embodiments of the present application, after preparing the interconnection circuit layer on the plurality of first driver wafers and the plurality of second driver wafers, the method further includes:

[0035] A plurality of driving surface pads are formed on a side of the semiconductor substrate away from the first driving wafer and the second driving wafer, and the driving surface pads are used to connect a power supply connector or a WIFI signal receiving device.

[0036] The present application provides a driving surface pad so that the micro light emitting diode display device can be connected to external components through a connector.

[0037] In some embodiments of the present application, the method further includes:

[0038] Inspecting the micro light emitting diode chips and repairing defective micro light emitting diode chips;

[0039] The detecting the micro light emitting diode chip and repairing the defective micro light emitting diode chip comprises:

[0040] Contacting a test probe with a test point disposed on a side of the semiconductor substrate away from the driver wafer to determine whether the micro light emitting diode chip connected to the driver wafer is defective;

[0041] If the chip is defective, the micro-LED chip is removed from the corresponding first micro-LED chip pad and the second micro-LED chip pad by laser stripping;

[0042] Replace the new micro-LED chip, place the new micro-LED chip on the corresponding first micro-LED chip pad and the second micro-LED chip pad, and connect the new micro-LED chip with the corresponding first micro-LED chip pad and the second micro-LED chip through laser heating.

[0043] The present application further improves the yield rate of the micro light emitting diode display device through detection and repair processes.

[0044] On the other hand, the present application provides an electronic device, comprising a bracket, wherein a plurality of brackets are detachably connected to the bracket, and a plurality of micro-LED display devices are mounted on each of the brackets, wherein the micro-LED display devices are manufactured by any of the above-described methods for manufacturing micro-LED display devices;

[0045] An adhesive layer is provided on one side of the bracket facing the micro-LED display device, and a plurality of the micro-LED display devices are adhesively fixed on the bracket.

[0046] In the electronic device of the present application, the micro-LED display device directly prepares the first driving wafer, the second driving wafer, the interconnection circuit layer, the first micro-LED chip pad and the second micro-LED chip pad on the semiconductor substrate, so that the micro-LED chip can be directly prepared on the first micro-LED chip pad and the second micro-LED chip pad, without the need to transfer a large number of micro-LED chips, which is conducive to improving the yield of the electronic device. The present application fixes the micro-LED display device on the bracket by bonding, eliminating the step of drilling a large number of holes on the micro-LED display device and the bracket, which is conducive to improving production efficiency.

[0047] In some embodiments of the present application, the micro-LED display device is provided with a plurality of positioning holes on a side facing the bracket; the bracket is provided with a plurality of positioning posts, the plurality of positioning posts correspond to the plurality of positioning holes one by one, and the positioning posts are inserted into the corresponding positioning holes;

[0048] The bracket is also provided with a plurality of hollow parts, and the plurality of hollow parts correspond one-to-one to the plurality of micro-LED display devices; the micro-LED display device is provided with a driving surface pad, and the hollow parts are used to expose the driving surface pad.

[0049] The present application provides a matching structure of positioning holes and positioning columns to facilitate rapid positioning of the micro-LED display device and the bracket, thereby improving production efficiency. The present application provides a hollow portion to reduce the overall weight of the bracket, thereby achieving lightweight; on the other hand, the driving surface pad can be exposed, thereby ensuring that the micro-LED display device is connected to external components.

[0050] In some embodiments of the present application, a plurality of power supplies are provided on one side of the bracket along the first direction, and the plurality of power supplies are arranged along the second direction;

[0051] The plurality of brackets are arranged in a plurality of columns along the first direction, and the plurality of brackets in each column corresponds to one power supply;

[0052] Plugs are provided on both sides of the bracket along the first direction, the power supply is connected to the plugs on the adjacent brackets via a power line, and two adjacent brackets are connected via a power line. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A simplified structural diagram of a micro light emitting diode display device provided in one embodiment of the present application;

[0054] Figure 2 A flow chart of a method for preparing a micro light emitting diode display device provided in one embodiment of the present application;

[0055] Figure 3 A simplified structural diagram of a semiconductor substrate provided in one embodiment of the present application after forming a micro-LED chip pad layer;

[0056] Figure 4 A simplified structural diagram of a micro light emitting diode chip provided in one embodiment of the present application;

[0057] Figure 5 A flow chart of a method for preparing a micro light emitting diode display device provided in another embodiment of the present application;

[0058] Figure 6 A flowchart of manufacturing a micro light emitting diode display device provided in one embodiment of the present application;

[0059] Figure 7 A simplified structural diagram of an electronic device provided in one embodiment of the present application;

[0060] Figure 8 A simplified structural diagram of a bracket and a micro-LED display device provided in one embodiment of the present application;

[0061] Fig. 9 A simplified structural diagram of a first surface of a bracket provided in an embodiment of the present application;

[0062] Fig.10 A simplified structural diagram of the second surface of the bracket provided in one embodiment of the present application;

[0063] Fig.11 A simplified structural diagram of the third surface of the bracket provided in one embodiment of the present application;

[0064] Fig.12 This is a simplified structural diagram of a micro light emitting diode display device provided in one embodiment of the present application.

[0065] Reference numerals:

[0066] 10- micro light emitting diode display device; 11- positioning hole;

[0067] 20-bracket; 21-adhesive layer; 22-positioning column; 23-hollow portion; 24-plug; 25-connecting portion;

[0068] 30- bracket; 31- power supply; 32- WIFI signal transmitting device;

[0069] 100 - light-emitting unit; 110 - first micro-LED light-emitting chip; 120 - second micro-LED light-emitting chip; 130 - third micro-LED light-emitting chip;

[0070] 210 - semiconductor substrate; 220 - driving wafer; 230 - interconnection circuit layer; 240 - first micro-LED chip pad; 250 - second micro-LED chip pad; 260 - driving surface pad; 270 - WIFI signal receiving device;

[0071] 310 - protective layer; 320 - Bragg reflection layer; 330 - transparent conductive layer; 340 - barrier layer; 350 - P-type semiconductor layer; 360 - light-emitting layer; 370 - N-type semiconductor layer; 380 - protrusion structure. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0073] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0074] In the related art, the micro-LED display device is mainly prepared by the mass transfer method. The general process is: the micro-LED chip is grabbed from the first substrate, and then transferred to the second substrate with a driving circuit, and assembled into a two-dimensional periodic array. In this process, the second substrate with the driving circuit is generally made of a PCB board or glass. During preparation, the driving circuit needs to be made first, and then the interconnection circuit layer is prepared on one side of the PCB board, and then the driving circuit is attached to the other side of the PCB board. However, the yield of the micro-LED display device using the solution of the related art is low.

[0075] In view of this, the present application aims to provide a method for preparing a micro-LED display device, the method comprises preparing a plurality of first driving wafers and a plurality of second driving wafers on a semiconductor substrate, each of the first driving wafer and the second driving wafer comprising a driving circuit for driving a micro-LED chip; then preparing an interconnection circuit layer on the plurality of first driving wafers and the plurality of second driving wafers; then preparing a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads on the interconnection circuit layer; and finally preparing a micro-LED chip by flip-chip on adjacent first micro-LED chip pads and second micro-LED chip pads. In the above manner, the present application directly prepares the first driving wafer, the second driving wafer, the interconnection circuit layer and the micro-LED chip pad on the semiconductor substrate, so that the micro-LED chip can be directly prepared on the micro-LED chip pad without the need for mass transfer of the micro-LED chip, which is beneficial to improving the yield of the micro-LED display device.

[0076] The contents of the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings so that those skilled in the art can understand the contents of the present application in more detail.

[0077] Figure 1 This is a simplified structural diagram of a micro light emitting diode display device provided in one embodiment of the present application.

[0078] like Figure 1 As shown, the micro-LED display device of this embodiment includes a plurality of light-emitting units 100 arranged in a plurality of arrays, each of the light-emitting units 100 includes a first micro-LED light-emitting chip 110, a second micro-LED light-emitting chip 120 and a third micro-LED light-emitting chip 130. When in use, the plurality of light-emitting units 100 are lit together to display colorful images.

[0079] Figure 2 This is a flow chart of a method for preparing a micro light emitting diode display device provided in one embodiment of the present application.

[0080] Please refer to Figure 2 This embodiment provides a method for preparing a micro light emitting diode display device, comprising:

[0081] Step S110: providing a semiconductor substrate.

[0082] The semiconductor substrate in this embodiment may be, for example, a silicon (Si) substrate. The semiconductor substrate in this embodiment has good high temperature resistance and can withstand the high temperature when semiconductor devices are grown and prepared thereon.

[0083] Step S120: forming a driving wafer layer on the semiconductor substrate, wherein the driving wafer layer includes a plurality of first driving wafers and a plurality of second driving wafers, and each of the first driving wafer and the second driving wafer includes a driving circuit for driving the micro light emitting diode chip.

[0084] In this embodiment, the first driver wafer and the second driver wafer are both based on complementary metal oxide semiconductor (CMOS), and the specific number can be determined as needed. Multiple first driver wafers and multiple second driver wafers are integrated on the same semiconductor substrate. The driving mode of the driving circuit can adopt active (AM) driving or passive (PM) driving. Among them, the driving circuit in the first driver wafer can provide a digital signal to drive the column tube, and the driving circuit in the second driver wafer can drive the row tube for power supply.

[0085] Step S130 , forming an interconnection circuit layer on the plurality of first driving wafers and the plurality of second driving wafers.

[0086] In this embodiment, the interconnection circuit layer may be a high-density (HDI) interconnection circuit layer, and the interconnection circuit layer is directly formed on a plurality of first drive wafers and a plurality of second drive wafers using a semiconductor process, so that the interconnection circuit layer is connected to the drive circuits in the first drive wafer and the second drive wafer. The semiconductor process when preparing the interconnection circuit layer may include: evaporation and patterning process (including exposure, development, etching and other steps). Compared with the copper cladding process used in the related art to prepare the interconnection circuit layer, the evaporation process used in this embodiment to prepare the interconnection circuit layer can ensure that the interconnection circuit layer has a higher precision.

[0087] In a possible implementation, the interconnection circuit layer of the present embodiment includes a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, a third insulating layer and a third metal layer which are stacked, and the steps of forming the interconnection circuit layer on the plurality of first driving wafers and the plurality of second driving wafers include:

[0088] A first insulating layer is formed by evaporating on the plurality of first driving wafers and the second driving wafer, a portion of the first insulating layer is removed by etching, and a plurality of first via holes are formed in the first insulating layer.

[0089] A first copper clad layer is formed by evaporation on the first insulating layer, and a first metal layer is formed by a patterning process. The first metal layer is connected to the first driving wafer or the second driving wafer through a first via hole.

[0090] A second insulating layer is formed by evaporation on the first metal layer, a portion of the second insulating layer is removed by etching, and a plurality of second via holes are formed on the second insulating layer.

[0091] A second copper cladding layer is formed on the second insulating layer by evaporation, and the first copper cladding layer is formed into a second metal layer by a patterning process.

[0092] A third insulating layer is formed by evaporating on the second metal layer, a portion of the third insulating layer is removed by etching, and a plurality of third via holes and a plurality of fourth via holes are formed on the third insulating layer, wherein the plurality of fourth via holes correspond one-to-one to the plurality of second via holes.

[0093] A third copper cladding layer is formed by evaporation on the third insulating layer, and a third metal layer is formed by a patterning process. The third metal layer is connected to the second metal layer through a third via hole, and the third metal layer is connected to the first metal layer through a fourth via hole and a second via hole.

[0094] In other possible implementations, the interconnection circuit layer may also be a structure including two metal layers, four metal layers, or five metal layers, and the specific number of interconnection circuit layers may be determined as needed.

[0095] Step S140: forming a micro LED chip pad layer on the interconnection circuit layer, wherein the micro LED chip pad layer includes a plurality of first micro LED chip pads and a plurality of second micro LED chip pads.

[0096] In this embodiment, the method for forming a micro-LED chip pad on the interconnection circuit layer is: evaporating pad metal on the interconnection circuit layer by metal organic chemical vapor deposition (MOCVD), and preparing the micro-LED chip pad through exposure, development, and etching processes.

[0097] In a possible implementation, the step of forming a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads on the interconnection circuit layer includes:

[0098] A fourth insulating layer is formed by evaporation on the third metal layer, a portion of the fourth insulating layer is removed by etching, and a plurality of fifth via holes are formed on the first insulating layer.

[0099] A conductive layer is formed by vapor deposition on the fourth insulating layer, and a portion of the conductive layer is removed by etching to form a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads, wherein the first micro-LED chip pads are connected to the third metal layer through fifth vias, and the height of the second micro-LED chip pads is greater than the height of the first micro-LED chip pads.

[0100] In this embodiment, the material of the conductive layer is gold or tin.

[0101] In a possible implementation manner, after forming the micro LED chip pad layer on the interconnection circuit layer, this embodiment may further form a plurality of driving surface pads on a side of the semiconductor substrate away from the first driving wafer and the second driving wafer.

[0102] In this embodiment, the driving surface pad can also be prepared by metal organic chemical vapor deposition to evaporate the pad metal, and then undergo exposure, development, and etching processes. The driving surface pad is used to weld external components such as board-to-board (BTB) connectors.

[0103] Figure 3 A simplified structural diagram of a semiconductor substrate provided in one embodiment of the present application after a micro-LED chip pad layer is formed.

[0104] like Figure 3 As shown, a driving wafer layer 220 is provided in the semiconductor substrate 210, and an interconnection circuit layer 230 is formed above the driving wafer layer 220, and the driving wafer layer 220 is connected to the interconnection circuit layer 230; a plurality of first micro-LED chip pads 240 and a plurality of second micro-LED chip pads 250 are provided on one side of the semiconductor substrate 210, wherein the first micro-LED chip pads 240 are connected to the interconnection circuit layer 230; a plurality of driving surface pads 260 are provided on the other side of the semiconductor substrate 210, and the driving surface pads 260 are used for welding external components such as connectors.

[0105] Step S150: forming a flip-chip micro LED chip on each adjacent first micro LED chip pad and second micro LED chip pad, and each micro LED chip is signal-connected to a first driving wafer and a second driving wafer.

[0106] Figure 4 A simplified structural diagram of a micro light emitting diode chip provided in one embodiment of the present application.

[0107] like Figure 4As shown, in a possible implementation manner, the micro LED chip of this embodiment includes a first micro LED chip pad 240 and a second micro LED chip pad 250 disposed at the bottom layer, and the height of the second micro LED chip pad 250 is greater than the height of the first micro LED chip pad 240. A protective layer 310 is filled between the first micro LED chip pad 240 and the second micro LED chip pad 250, and a Bragg reflection layer 320 is disposed above the first micro LED chip pad 240 and the protective layer 310, wherein the Bragg reflection layer 320 extends to the side of the second micro LED chip pad 250 facing the first micro LED chip pad 240. A first through hole is also formed in the Bragg reflection layer 320, and a portion of the first micro LED chip pad 240 is located in the first through hole, so that the Bragg reflection layer 320 and the first micro LED chip pad 240 form a first groove. A transparent conductive layer 330 is also provided on the Bragg reflection layer 330 located above the first micro-LED chip pad 240, and a second groove is formed on the side of the transparent conductive layer 330 away from the first groove. A barrier layer 340 is provided in the second groove. A P-type semiconductor layer 350 is provided on the barrier layer 340 and the transparent conductive layer 330, and the P-type semiconductor layer is connected to the first micro-LED chip pad 240. A light-emitting layer 360 is provided on the P-type semiconductor layer 350. An N-type semiconductor layer 370 is also provided on the light-emitting layer 360, and the N-type semiconductor layer 370 is connected to the second micro-LED chip pad 250. The surface of the N-type semiconductor layer 370 is patterned to obtain a plurality of protruding structures 380.

[0108] In this embodiment, the step of forming a flip-chip micro LED chip on each adjacent first micro LED chip pad and second micro LED chip pad includes:

[0109] A protective layer is deposited on the fourth insulating layer so that the protective layer fills between each adjacent first micro-LED chip pad and a second micro-LED chip pad; in this embodiment, the protective layer can be a silicon dioxide (SiO2) layer, which can effectively block moisture and prevent metal migration.

[0110] A Bragg reflection (DBR) layer is formed on the protective layer and the adjacent first micro-LED chip pad, so that the Bragg reflection layer covers the side of the second micro-LED chip pad facing the first micro-LED chip pad, and a first through hole is also formed in the Bragg reflection layer. The first micro-LED chip pad is partially located in the first through hole, so that the Bragg reflection layer and the first micro-LED chip pad form a first groove.

[0111] A transparent conductive layer is formed on the Bragg reflective layer. In this embodiment, the transparent conductive layer may be an indium tin oxide (ITO) layer. A second groove is formed on a side of the transparent conductive layer away from the first groove.

[0112] A barrier layer is deposited in the second recess.

[0113] A P-type semiconductor layer is formed on the transparent conductive layer and the barrier layer, and the P-type semiconductor layer is connected to the first micro light emitting diode chip pad.

[0114] A light emitting layer is formed on the P-type semiconductor layer.

[0115] An N-type semiconductor layer is formed on the light-emitting layer, and the N-type semiconductor layer is connected to the second micro light-emitting diode chip pad.

[0116] In this embodiment, the plurality of micro-LED chips include a plurality of first light-emitting chips, a plurality of second light-emitting chips, and a plurality of third light-emitting chips, and the light-emitting colors of the first light-emitting chips, the second light-emitting chips, and the third light-emitting chips are different from each other. For example, the first light-emitting chip can emit blue light, the second light-emitting chip can emit green light, and the third light-emitting chip can emit red light.

[0117] In one possible implementation, when manufacturing micro-LED chips, they can be manufactured in order according to the different luminous colors of the micro-LED chips. For example, a micro-LED chip emitting blue light can be manufactured first, and the undeposited micro-LED chip pads can be left by photoresist exposure, development, and etching; then, a micro-LED chip emitting green light can be prepared on the remaining micro-LED chip pads in the same manner, and several undeposited micro-LED chip pads can be left by photoresist exposure, development, and etching; finally, a micro-LED chip emitting red light can be manufactured on the remaining several micro-LED chip pads.

[0118] In this embodiment, in the micro-LED chip that emits blue light and the micro-LED chip that emits green light, the P-type semiconductor layer can be selected as a P-type gallium nitride (P-GaN) layer, and the N-type semiconductor layer can be selected as an N-type gallium nitride (N-GaN) layer; in the micro-LED chip that emits red light, the P-type semiconductor layer can be selected as a P-type gallium phosphide (P-GaP) layer, and the N-type semiconductor layer can be selected as an N-type gallium phosphide (N-GaP) layer.

[0119] From the above description, it can be seen that in this embodiment, the first driving wafer, the second driving wafer, the interconnection circuit layer and the micro-LED chip pad are directly prepared on the semiconductor substrate, so that the micro-LED chip can be directly prepared on the micro-LED chip pad without the need for mass transfer of the micro-LED chips, which is beneficial to improving the yield of the micro-LED display device.

[0120] Figure 5 This is a flow chart of a method for preparing a micro light emitting diode display device provided in another embodiment of the present application.

[0121] Please refer to Figure 5 , the method of this embodiment includes:

[0122] Step S210: providing a semiconductor substrate.

[0123] Step S220: forming a plurality of first driving wafers and a plurality of second driving wafers on a semiconductor substrate, wherein each of the first driving wafer and the second driving wafer comprises a driving circuit for driving the micro light emitting diode chip.

[0124] Step S230 , forming an interconnection circuit layer on the plurality of first driving wafers and the second driving wafers.

[0125] Step S240: forming a micro LED chip pad layer on the interconnection circuit layer, wherein the micro LED chip pad layer includes a plurality of first micro LED chip pads and a plurality of second micro LED chip pads.

[0126] Step S250: forming a flip-chip micro LED chip on each adjacent first micro LED chip pad and second micro LED chip pad, and each micro LED chip is signal-connected to a first driving wafer and a second driving wafer.

[0127] Among them, step S210 to step S250 are completely the same as step S110 to step S150 in the above embodiment, and will not be repeated in this embodiment.

[0128] Step S260: inspect the micro LED chips and repair defective micro LED chips.

[0129] In a possible implementation, inspecting micro light emitting diode chips and repairing defective micro light emitting diode chips includes:

[0130] The test probe is contacted with a test point arranged on a side of the semiconductor substrate away from the first driving wafer and the second driving wafer to determine whether the micro light emitting diode chip connected to the first driving wafer and the second driving wafer is defective.

[0131] If the micro LED chip is defective, laser stripping is used to remove the micro LED chip from the corresponding first micro LED chip pad and the second micro LED chip pad.

[0132] Replace the new micro LED chip, place the new micro LED chip on the corresponding first micro LED chip pad and the second micro LED chip pad, and connect the new micro LED chip with the corresponding first micro LED chip pad and the second micro LED chip by laser heating.

[0133] This embodiment further improves the yield rate of the micro light emitting diode display device through the detection and repair process.

[0134] Step S270: packaging the micro light emitting diode display device.

[0135] In this embodiment, the micro-LED display device can be packaged by using a release film compression molding process, wherein the packaging material can be liquid silicone, solid silicone, epoxy resin, modified resin or UV curable resin.

[0136] In this embodiment, the first driving wafer, the second driving wafer, the interconnection circuit layer and the micro-LED chip pad are directly prepared on the semiconductor substrate, so that the micro-LED chip can be directly prepared on the micro-LED chip pad without mass transfer of the micro-LED chip, which is conducive to improving the yield of the micro-LED display device. In addition, through the rework step, this embodiment further improves the yield of the micro-LED display device.

[0137] Figure 6 A flowchart of the preparation of a micro light emitting diode display device provided in one embodiment of the present application.

[0138] like Figure 6 As shown, in a possible implementation, the preparation process of the micro-LED display device of this embodiment is: forming multiple CMOS drive wafers (including a first drive wafer and a second drive wafer) on a semiconductor substrate; forming a drive circuit on the CMOS drive wafer; forming an interconnection circuit layer on the basis of the drive circuit; forming multiple micro-LED chip pads and multiple drive surface pads on both sides of the semiconductor substrate. Then, the micro-LED chip is flipped and prepared, and the preparation process is: evaporating a protective layer; obtaining a predetermined patterned structure after processes such as coating, exposure, development, and etching.

[0139] Then, a blue DBR layer and a green DBR layer, a blue ITO layer and a green ITO layer are evaporated on the pad of the micro-LED chip and the protective layer; then a blue blocking layer and a green blocking layer, a blue P-GaN layer and a green P-GaN layer are formed in sequence; after photoresist coating, exposure, development and etching, the light-emitting layer area of ​​the blue light-emitting chip is obtained to form a blue light-emitting layer; then, after photoresist stripping, cleaning, photoresist coating, exposure, development and etching, the light-emitting layer area of ​​the green light-emitting chip is obtained to form a green light-emitting layer; then, after photoresist stripping, cleaning, photoresist coating, exposure, development and etching, a blue N-GaN layer and a green N-GaN layer are formed; finally, a PSS (patterned sapphire substrate) is made on the blue N-GaN layer and the green N-GaN layer to obtain several green micro-LED chips and several blue micro-LED chips. After photoresist stripping, cleaning, coating, exposure, development, and etching, the light-emitting layer area of ​​the red light-emitting chip is obtained; then the red light DBR layer, red light ITO layer, red light blocking layer, red light P-GaP layer, red light emitting layer, and red light N-GaP layer are sequentially evaporated, and finally PSS is made on the red light N-GaP layer to obtain several red light-emitting chips. Finally, the gap is roughened, and after photoresist stripping and cleaning, the micro light-emitting diode display device is obtained.

[0140] Please continue to refer to Figure 6 After the preparation of the micro-LED display device in this embodiment is completed, it also includes a detection and repair process to replace the defective micro-LED chips with normal micro-LED chips, thereby ensuring the yield of the micro-LED display device. Then the micro-LED display device is packaged, and the connector is welded on the driving surface pad to achieve connection with external components.

[0141] The micro-LED display device of this embodiment directly prepares the first driving wafer, the second driving wafer, the interconnection circuit layer and the micro-LED chip pad on the semiconductor substrate, so that the micro-LED chip can be directly prepared on the micro-LED chip pad without the need for mass transfer of the micro-LED chips, which is beneficial to improving the yield of the micro-LED display device.

[0142] Figure 7 A simplified structural diagram of an electronic device provided in one embodiment of the present application; Figure 8 A simplified structural diagram of a bracket and a micro-LED display device provided in an embodiment of the present application; Fig. 9 A simplified structural diagram of a first surface of a bracket provided in an embodiment of the present application; Fig.10 A simplified structural diagram of the second surface of the bracket provided in one embodiment of the present application; Fig.11 A simplified structural diagram of the third surface of the bracket provided in one embodiment of the present application; Fig.12This is a simplified structural diagram of a micro light emitting diode display device provided in one embodiment of the present application.

[0143] Please refer to Figure 7-Figure 12 This embodiment also provides an electronic device, including a bracket 30, on which a plurality of brackets 20 are detachably connected, and each bracket 20 is mounted with a plurality of micro-LED display devices 10, wherein the micro-LED display device 10 is manufactured using the above-mentioned method for manufacturing a micro-LED display device.

[0144] Specifically, in the present embodiment, the shape of the bracket 30 can be set as needed, for example, it can be in the shape of a rectangular parallelepiped. The entire bracket 30 can be made of a metal with high strength to provide stable support. The number of brackets 20 on the bracket 30 can be set as needed. The shape and number of the micro-LED display device 10 can be set as needed. For example, the micro-LED display device 10 can be in the shape of a rectangular parallelepiped, and each bracket 20 is provided with four micro-LED display devices 10. The shape of the bracket 20 is similar to the shape formed by the multiple micro-LED display devices 10, for example, they can all be rectangular. The micro-LED display device 10 and the bracket 20 can be connected and fixed by bonding, screwing, etc.

[0145] In the electronic device of the present embodiment, the micro-LED display device 10 directly prepares the first driving wafer, the second driving wafer, the interconnection circuit layer, the first micro-LED chip pad and the second micro-LED chip pad on the semiconductor substrate, so that the micro-LED chip can be directly prepared on the first micro-LED chip pad and the second micro-LED chip pad, without the need for mass transfer of the micro-LED chips, which is beneficial to improving the yield of the electronic device.

[0146] In a possible implementation manner, an adhesive layer 21 is provided on a side of the bracket 20 facing the micro LED display device 10 , and a plurality of micro LED display devices 10 are adhesively fixed to the bracket 20 .

[0147] In this embodiment, the micro LED display device 10 is fixed to the bracket 20 by bonding, which eliminates the step of punching a large number of holes in the micro LED display device 10 and the bracket 20, thereby improving production efficiency.

[0148] Furthermore, the adhesive layer 21 is a moisture-curing reactive polyurethane hot melt adhesive (PolyurethaneReactive, PUR for short) layer. The moisture-curing reactive polyurethane hot melt adhesive layer has good adhesion, is resistant to high cold and high heat, and has a long service life.

[0149] In a possible implementation, the micro-LED display device 10 of this embodiment is provided with a plurality of positioning holes 11 on the side facing the bracket 20; the bracket 20 is provided with a plurality of positioning posts 22, the plurality of positioning posts 22 correspond one-to-one to the plurality of positioning holes 11, and the positioning posts 22 are inserted into the corresponding positioning holes 11.

[0150] For example, the micro-LED display device 10 of this embodiment is provided with two positioning holes 11, and the two positioning holes 11 are respectively arranged at two diagonal positions on the micro-LED display device 10. Thus, when installing the micro-LED display device 10, the two positioning posts 22 must be respectively inserted into the two positioning holes 11, and the micro-LED display device 10 can be bonded and fixed to the adhesive layer 21, thereby playing the role of installation positioning and guiding. At the same time, by providing the matching structure of the positioning holes 11 and the positioning posts 22, it is convenient to quickly position the micro-LED display device 10 and the bracket 20, thereby helping to improve production efficiency.

[0151] In one possible implementation, the bracket 20 of this embodiment is further provided with a plurality of hollow portions 23, and the plurality of hollow portions 23 correspond one to one with the plurality of micro-LED display devices 10. For example, in this embodiment, the bracket 20 is provided with four hollow portions 23, and the four hollow portions 23 correspond to four micro-LED display devices 10, respectively. The micro-LED display device 10 is provided with a driving surface pad 260, and the hollow portion 23 is used to expose the driving surface pad 260. It can be understood that the micro-LED display device 10 is bonded to the bracket 20 on all sides, and the middle area of ​​the micro-LED display device 10 is exposed by the hollow portion 23, thereby ensuring that the micro-LED display device 10 can be connected to external components through the driving surface pad 260. By providing the hollow portion 23, the overall weight of the bracket 20 can also be reduced, which is conducive to lightweighting.

[0152] In a possible implementation, in order to realize power supply to the micro-LED display device 10, the bracket 30 of this embodiment is provided with a plurality of power supplies 31 on one side along the first direction X, and the plurality of power supplies 31 are arranged along the second direction Y. The plurality of brackets 20 are arranged in a plurality of rows along the first direction X, and the plurality of brackets 20 in each row correspond to a power supply 31. Plugs 24 are provided on both sides of the bracket 20 along the first direction X, and the power supply 31 is connected to the plug 24 on the adjacent bracket 20 through a power line, and the two adjacent brackets 20 are connected through the power line, thereby realizing the transmission of electric energy from the power supply 31 to each bracket 20. Furthermore, a power supply connector is connected to the driving surface pad 260, and the power supply connector is connected to the plug 24 on the bracket 20 through the power line, thereby realizing the transmission of electric energy from the bracket 20 to each micro-LED display device 10.

[0153] Optionally, in order to achieve communication of the micro-LED display device 10, this embodiment further provides a WIFI signal transmitting device 32 on one side of the bracket 30 along the first direction X, and a WIFI signal receiving device 270 is connected to the driving surface pad 260, and the WIFI signal transmitting device 32 is communicatively connected to the WIFI signal receiving device 270.

[0154] In a possible implementation manner, in order to better fix the bracket 20 , a plurality of connecting parts 25 are provided on the side of the bracket 20 facing the support 30 in this embodiment, and the bracket 20 is detachably connected to the support 30 via the connecting parts.

[0155] Optionally, the connecting portion 25 may be a magnet, and the bracket 20 is adsorbed on the bracket 30 via the magnet;

[0156] Alternatively, the connecting portion 25 may be a threaded hole, and the bracket 30 is provided with a corresponding through hole, and the fastener passes through the through hole and is fixed in the threaded hole.

[0157] Furthermore, in this embodiment, the bracket 20 may be a die-cast aluminum bracket 20 or a plastic bracket 20, so that the bracket 20 itself is relatively light, which is beneficial to making the entire electronic device lightweight.

[0158] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0159] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0160] It should be noted that in the description of this application, the terms "first" and "second" are only used to facilitate the description of different components, and cannot be understood as indicating or implying a sequential relationship, relative importance, or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0161] The various embodiments or implementation methods in the present application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0162] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In the present application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. 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 micro light emitting diode display device, characterized in that: include: providing a semiconductor substrate; Forming a plurality of first driving wafers and a plurality of second driving wafers on the semiconductor substrate, each of the first driving wafer and the second driving wafer comprising a driving circuit for driving a micro light emitting diode chip; forming an interconnection circuit layer on the plurality of the first driving wafers and the plurality of the second driving wafers; the interconnection circuit layer comprises a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, a third insulating layer and a third metal layer which are stacked; forming a plurality of first micro light emitting diode chip pads and a plurality of second micro light emitting diode chip pads on the interconnection circuit layer; A flip-chip micro LED chip is formed on each adjacent first micro LED chip pad and second micro LED chip pad, and each of the micro LED chips is signal-connected to one of the first driving wafers and one of the second driving wafers; The step of forming a flip-chip micro-LED chip on each adjacent first micro-LED chip pad and each adjacent second micro-LED chip pad comprises: depositing a protective layer on the fourth insulating layer so that the protective layer is filled between each adjacent first micro-LED chip pad and each adjacent second micro-LED chip pad, wherein the fourth insulating layer is formed by evaporation on the third metal layer; A Bragg reflection layer is formed on the protective layer and the adjacent first micro-LED chip pad, so that the Bragg reflection layer covers the side of the second micro-LED chip pad facing the first micro-LED chip pad, a first through hole is further formed in the Bragg reflection layer, and the first micro-LED chip pad is partially located in the first through hole, so that the Bragg reflection layer and the first micro-LED chip pad form a first groove; forming a transparent conductive layer on the Bragg reflective layer, wherein a second groove is formed on a side of the transparent conductive layer away from the first groove; Depositing a barrier layer in the second groove; forming a P-type semiconductor layer on the transparent conductive layer and the barrier layer, wherein the P-type semiconductor layer is connected to the first micro-LED chip pad; A light emitting layer is formed on the P-type semiconductor layer; and an N-type semiconductor layer is formed on the light emitting layer, wherein the N-type semiconductor layer is connected to the second micro light emitting diode chip pad.

2. The method for preparing a micro light emitting diode display device according to claim 1, characterized in that: The step of forming an interconnection circuit layer on the plurality of the first driving wafers and the plurality of the second driving wafers comprises: Forming a first insulating layer by evaporation on the plurality of first driving wafers and the plurality of second driving wafers, etching and removing a portion of the first insulating layer, and forming a plurality of first via holes in the first insulating layer; Forming a first copper-clad layer by evaporation on the first insulating layer, and forming a first metal layer through a patterning process so that the first copper-clad layer is connected to the first driving wafer or the second driving wafer through the first via hole; Forming a second insulating layer by evaporating on the first metal layer, removing a portion of the second insulating layer by etching, and forming a plurality of second via holes on the second insulating layer; Forming a second copper-clad layer by evaporation on the second insulating layer, and forming a second metal layer through a patterning process on the first copper-clad layer; Forming a third insulating layer by evaporating on the second metal layer, removing a portion of the third insulating layer by etching, and forming a plurality of third via holes and a plurality of fourth via holes on the third insulating layer, wherein the plurality of fourth via holes correspond one to one to the plurality of second via holes; A third copper clad layer is formed by vapor deposition on the third insulating layer, and a third metal layer is formed by a patterning process. The third metal layer is connected to the second metal layer through the third via hole, and the third metal layer is connected to the first metal layer through the fourth via hole and the second via hole.

3. The method for preparing a micro light emitting diode display device according to claim 2, characterized in that: The step of forming a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads on the interconnection circuit layer comprises: forming a fourth insulating layer by evaporating on the third metal layer, removing a portion of the fourth insulating layer by etching, and forming a plurality of fifth via holes on the first insulating layer; Forming a conductive layer by evaporating on the fourth insulating layer, and removing a portion of the conductive layer by etching to form a plurality of first micro-LED chip pads and a plurality of second micro-LED chip pads, wherein the first micro-LED chip pads are connected to the third metal layer through the fifth via holes, and the height of the second micro-LED chip pads is greater than the height of the first micro-LED chip pads; The material of the conductive layer is gold or tin.

4. The method for preparing a micro light emitting diode display device according to claim 1, characterized in that: The plurality of micro light emitting diode chips include a plurality of first light emitting chips, a plurality of second light emitting chips and a plurality of third light emitting chips, and the light emitting colors of the first light emitting chips, the second light emitting chips and the third light emitting chips are different from each other.

5. The method for preparing a micro light emitting diode display device according to claim 1, characterized in that: After preparing the interconnection circuit layer on the plurality of the first driver wafers and the plurality of the second driver wafers, the method further includes: A plurality of driving surface pads are formed on a side of the semiconductor substrate away from the first driving wafer and the second driving wafer, and the driving surface pads are used to connect a power supply connector or a WIFI signal receiving device.

6. The method for preparing a micro light emitting diode display device according to any one of claims 1 to 5, characterized in that: After forming a flip-chip micro LED chip on each adjacent first micro LED chip pad and second micro LED chip pad, the method further includes: Inspecting the micro light emitting diode chips and repairing defective micro light emitting diode chips; The detecting the micro light emitting diode chip and repairing the defective micro light emitting diode chip comprises: Contacting a test probe with a test point disposed on a side of the semiconductor substrate away from the first driver wafer and the second driver wafer to determine whether the micro light emitting diode chip connected to the first driver wafer and the second driver wafer is defective; If the chip is defective, the micro-LED chip is removed from the corresponding first micro-LED chip pad and the second micro-LED chip pad by laser stripping; Replace the new micro-LED chip, place the new micro-LED chip on the corresponding first micro-LED chip pad and the second micro-LED chip pad, and connect the new micro-LED chip with the corresponding first micro-LED chip pad and the second micro-LED chip through laser heating.

7. An electronic device, characterized in that: A bracket is provided, wherein a plurality of brackets are detachably connected to the bracket, and a plurality of micro-LED display devices are mounted on each of the brackets, wherein the micro-LED display devices are manufactured by the method for manufacturing a micro-LED display device according to any one of claims 1 to 6; An adhesive layer is provided on one side of the bracket facing the micro-LED display device, and a plurality of the micro-LED display devices are adhesively fixed on the bracket.

8. The electronic device according to claim 7, characterized in that: A plurality of positioning holes are provided on one side of the micro-LED display device facing the bracket; a plurality of positioning posts are provided on the bracket, and the plurality of positioning posts correspond to the plurality of positioning holes one by one, and the positioning posts are inserted into the corresponding positioning holes; The bracket is also provided with a plurality of hollow parts, and the plurality of hollow parts correspond one by one to the plurality of micro-LED display devices; The micro-LED display device is provided with a driving surface pad, and the hollow portion is used to expose the driving surface pad.

9. The electronic device according to claim 8, characterized in that: A plurality of power supplies are provided on one side of the bracket along the first direction, and the plurality of power supplies are arranged along the second direction; The plurality of brackets are arranged in a plurality of columns along the first direction, and the plurality of brackets in each column corresponds to one power supply; Plugs are provided on both sides of the bracket along the first direction, the power supply is connected to the plugs on the adjacent brackets via a power line, and two adjacent brackets are connected via a power line.

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