CN115863497B

CN115863497B - Micro LED display device and preparation method thereof

Info

Publication number: CN115863497B
Application number: CN202310134456.6A
Authority: CN
Inventors: 张闹; 仉旭; 庄永漳; 曾鸿图; 卢子元
Original assignee: Laiyu Optoelectronic Technology Suzhou Co ltd
Current assignee: Laiyu Optoelectronic Technology Suzhou Co ltd
Priority date: 2023-02-20
Filing date: 2023-02-20
Publication date: 2023-05-23
Anticipated expiration: 2043-02-20
Also published as: CN115863497A; WO2024174829A1

Abstract

The application discloses a micro LED display device and a preparation method thereof, which belong to the technical field of micro display and comprise a driving substrate, a bonding layer and a plurality of first LED units, wherein the bonding layer is arranged on the driving substrate, the first LED units are arranged on the driving substrate in an array manner, and the first LED units are used for emitting first color light; providing a second LED epitaxial layer, wherein the second LED epitaxial layer is provided with a plurality of first avoidance holes; bonding the second LED epitaxial layer with the driving substrate and covering the first LED unit, wherein the position of the first avoidance hole corresponds to the position of the first LED unit; etching the second LED epitaxial layer to form a plurality of second LED units and exposing the first LED units, wherein the second LED units are arranged on the driving substrate in an array manner and used for emitting second color light; the first LED unit and the second LED unit can be independently driven by the driving substrate. The method can reduce the preparation difficulty and improve the yield.

Description

Micro LED display device and preparation method thereof

Technical Field

The application belongs to the technical field of micro display, and particularly relates to a micro LED display device and a preparation method thereof.

Background

Micro-display micro LEDs are also called micro light emitting diodes, and refer to high-density integrated LED arrays, and are realized through LED miniaturization and matrixing, and compared with traditional LED display screens, the micro LEDs are different in processes such as crystal grains, packaging, integration processes, backboard, driving and the like. In a micro LED array, the LED unit distance is on the order of 0.1-110 microns, and each LED pixel is self-luminous. Because the chip with the same area can obtain higher integration quantity, the photoelectric conversion efficiency of the micro LED is greatly improved, and the display design with high resolution and high brightness can be realized.

The full-color micro-display has a wide and important application value, especially near-to-eye display including AR, VR, etc., however, the technology for realizing full-color micro-display still has a large improvement space. In particular, currently, micro led display devices generally integrate a wavelength conversion layer on a single-color display chip, and the RGB three primary colors required by full-color display are set to meet the requirement of full-color display. However, the smaller the LED unit of the micro LED display device, the more difficult the wavelength conversion layer is to fabricate, making the fabrication difficult significantly increased.

Disclosure of Invention

The invention aims to: the embodiment of the application provides a micro LED display device and a preparation method thereof, and aims to solve the technical problem that the existing micro LED display device adopts the mode that a wavelength conversion layer is integrated on a monochromatic display chip, so that the preparation difficulty is high.

The technical scheme is as follows: the preparation method of the micro LED display device provided by the embodiment of the application comprises the following steps:

providing a driving substrate, a bonding layer and a plurality of first LED units, wherein the bonding layer is arranged on the driving substrate, the first LED units are arranged above the driving substrate in an array manner, and the first LED units are used for emitting light of a first color;

providing a second LED epitaxial layer, wherein the second LED epitaxial layer is provided with a plurality of first avoidance holes;

Bonding the second LED epitaxial layer with the driving substrate and covering the first LED unit, wherein the position of the first avoidance hole corresponds to the position of the first LED unit;

etching the second LED epitaxial layer to form a plurality of second LED units and exposing the first LED units, wherein the second LED units are arranged above the driving substrate in an array manner and used for emitting second color light;

the first LED unit and the second LED unit can be independently driven by the driving substrate.

In some embodiments, the step of providing a plurality of first LED units comprises:

providing a first LED epitaxial layer, wherein the first LED epitaxial layer is arranged on a first substrate;

bonding the first LED epitaxial layer with the driving substrate through the bonding layer;

removing the first substrate;

and etching the first LED epitaxial layer to form a plurality of first LED units which are arrayed above the driving substrate.

In some embodiments, the step of providing a second LED epitaxial layer comprises:

providing a second LED epitaxial layer, wherein the second LED epitaxial layer is arranged on a second substrate;

forming a bonding layer on the second LED epitaxial layer, and etching the bonding layer and the second LED epitaxial layer to form a plurality of first avoidance holes;

The second substrate is removed after bonding the second LED epitaxial layers to the drive substrate.

In some embodiments, the depth of the first relief hole is greater than the height of the first LED unit.

In some embodiments, the step of etching the second LED epitaxial layer to form a plurality of second LED units and exposing the first LED units comprises:

forming a first mask protection layer above the second LED epitaxial layer, wherein the first mask protection layer shields the first LED unit, and the first mask protection layer shields a region of the second LED epitaxial layer for forming the second LED unit;

the second LED epitaxial layer is etched to form the second LED unit and then the first mask protection layer is removed.

In some embodiments, before forming the first mask protection layer over the second LED epitaxial layer, further comprises:

and thinning the second LED epitaxial layer until the light emitting surface of the first LED unit is exposed.

In some embodiments, the method for manufacturing a micro led display device further includes:

providing a third LED epitaxial layer, wherein a plurality of second avoidance holes are formed in the third LED epitaxial layer;

bonding the third LED epitaxial layer with the driving substrate and covering the first LED unit and the second LED unit, wherein the positions of the second avoidance holes correspond to the positions of the first LED unit and the second LED unit;

Etching the third LED epitaxial layer to form a plurality of third LED units and exposing the first LED units and the second LED units, wherein the third LED units are arranged on the driving substrate in an array manner and used for emitting third color light;

the third LED unit can be independently driven by the driving substrate.

In some embodiments, the depth of the second relief hole is greater than the height of the first LED unit and the second LED unit.

In some embodiments, providing a third LED epitaxial layer, bonding the third LED epitaxial layer to the drive substrate and covering the first LED unit and the second LED unit comprises:

the step of providing a third LED epitaxial layer comprises:

providing a third LED epitaxial layer, wherein the third LED epitaxial layer is arranged on a third substrate;

forming a bonding layer on the third LED epitaxial layer, and etching the bonding layer and the third LED epitaxial layer to form a plurality of second avoidance holes;

the third substrate is removed after bonding the third LED epitaxy to the drive substrate.

In some embodiments, the step of etching the third LED epitaxial layer to form a plurality of third LED units and exposing the first LED units and the second LED units comprises:

Forming a third mask protection layer over the third LED epitaxial layer, the third mask protection layer shielding the first LED unit and the second LED unit, and the third mask protection layer shielding a region of the third LED epitaxial layer used to form the third LED unit;

and etching the third LED epitaxial layer to form the third LED unit and then removing the third mask protection layer.

In some embodiments, before forming the third mask protection layer over the third LED epitaxial layer, further comprising:

and thinning the third LED epitaxial layer to expose the light emitting surfaces of the first LED unit and the second LED unit.

In some embodiments, the drive substrate includes a plurality of contacts including a first contact and a second contact;

the bonding layer is made of conductive materials, the first doped semiconductor layer of the first LED unit is electrically connected with the first contact through the bonding layer, the first doped semiconductor layer of the second LED unit is electrically connected with the first contact through the bonding layer, and the second doped semiconductor layer of the first LED unit and the second doped semiconductor layer of the second LED unit are electrically connected with the second contact through the common electrode layer.

the bonding layer is made of conductive materials, the first doped semiconductor layer of the first LED unit is electrically connected with the first contact through the bonding layer, the first doped semiconductor layer of the second LED unit is electrically connected with the first contact through the bonding layer, the first doped semiconductor layer of the third LED unit is electrically connected with the first contact through the bonding layer, and the second doped semiconductor layer of the first LED unit, the second doped semiconductor layer of the second LED unit and the second doped semiconductor layer of the third LED unit are electrically connected with the second contact through the common electrode layer.

In some embodiments, the second relief hole does not penetrate the third LED epitaxial layer.

Accordingly, the embodiment of the application provides a micro led display device, which includes:

a driving substrate;

the bonding layer is arranged on the driving substrate;

the first LED units are arranged above the driving substrate in an array manner and used for emitting first color light;

The second LED units are arranged on the driving substrate in an array manner and used for emitting second color light;

the first LED unit and the second LED unit can be independently driven.

In some embodiments, the micro led display device further comprises:

the plurality of third LED units are arranged on the driving substrate in an array manner, and the third LED units are used for emitting third color light;

the third LED unit can be independently driven by the driving substrate.

the bonding layer is made of conductive materials, the first doped semiconductor layer of the first LED unit is electrically connected with the first contact through the bonding layer, the first doped semiconductor layer of the second LED unit is electrically connected with the first contact through the bonding layer, and the second doped semiconductor layer of the first LED unit and the second doped semiconductor layer of the second LED unit are electrically connected with the second contact through the electrode layer.

The bonding layer is made of conductive materials, the first doped semiconductor layer of the third LED unit is electrically connected with the first contact through the bonding layer, and the second doped semiconductor layer of the third LED unit is electrically connected with the second contact through the electrode layer.

In some embodiments, the first color light, the second color light, and the third color light are each selected from the group consisting of: red light, green light, and blue light.

In some embodiments, the first LED unit has a size of 0.1 to 5 microns.

In some embodiments, the second LED unit has a size of 0.1 to 5 microns.

In some embodiments, the third LED unit has a size of 0.1 to 5 microns.

In some embodiments, the first LED unit, the second LED unit, and the third LED unit have dimensions of 0.1-5 microns; the distance between the adjacent first LED unit, second LED unit and third LED unit is 1-10 microns.

In some embodiments, the side of the first LED unit is provided with a passivation layer.

In some embodiments, the side of the second LED unit is provided with a passivation layer.

In some embodiments, the side of the third LED unit is provided with a passivation layer.

In some embodiments, at least one of the first LED units, at least one of the second LED units, and at least one of the third LED units form one full-color pixel point of the micro LED display device.

The beneficial effects are that: compared with the prior art, the preparation method of the micro LED display device comprises the following steps: providing a driving substrate, a bonding layer and a plurality of first LED units, wherein the bonding layer is arranged on the driving substrate, the first LED units are arranged above the driving substrate in an array manner, and the first LED units are used for emitting first color light; providing a second LED epitaxial layer, wherein the second LED epitaxial layer is provided with a plurality of first avoidance holes; bonding the second LED epitaxial layer with the driving substrate and covering the first LED unit, wherein the position of the first avoidance hole corresponds to the position of the first LED unit; etching the second LED epitaxial layer to form a plurality of second LED units and exposing the first LED units, wherein the second LED units are arranged on the driving substrate in an array manner and used for emitting second color light; the first LED unit and the second LED unit can be independently driven by the driving substrate. According to the preparation method, the first LED unit and the second LED unit are sequentially prepared, and the first avoidance holes are formed in the second LED epitaxial layer skillfully during preparation, so that the second LED epitaxial layer and the driving substrate are bonded smoothly, the second LED unit is prepared by using an etching process, the preparation difficulty is reduced, and the yield of the display device is improved.

Compared with the prior art, the micro LED display device of the embodiment of the application comprises: a driving substrate; the bonding layer is arranged on the driving substrate; the first LED units are arranged above the driving substrate in an array manner and used for emitting first color light; the second LED units are arranged above the driving substrate in an array mode, are arranged adjacent to the first LED units and are used for emitting second color light; the first LED unit and the second LED unit can be independently driven by the driving substrate. The display device directly emits light with different colors through different LED units, full-color display is realized, an integrated wavelength conversion layer is not needed, the preparation difficulty is reduced, and the yield of the display device is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a front view structure of a micro led display device according to an embodiment of the present application;

FIG. 2 is a schematic cross-sectional view of the micro LED display device of FIG. 1 taken along line A-A';

FIG. 3 is a schematic cross-sectional view of a drive substrate and bonding layer of a micro LED display device of an embodiment of the present application;

FIG. 4 is a schematic cross-sectional view of a bonding process of a drive substrate to a first LED epitaxial layer;

FIG. 5 is a schematic cross-sectional view of the process of removing the substrate after bonding the drive substrate to the first LED epitaxial layer;

FIG. 6 is a schematic cross-sectional view of a process of forming a first LED unit on a first LED epitaxial layer;

FIG. 7 is a schematic cross-sectional structure after forming a first LED unit;

FIG. 8 is a schematic cross-sectional view of a process of forming a first relief hole in a second LED epitaxial layer;

FIG. 9 is a schematic cross-sectional view of a bonding process of a second LED epitaxial layer to a drive substrate;

FIG. 10 is a schematic cross-sectional view of the second LED epitaxial layer bonded to the drive substrate with the substrate removed;

FIG. 11 is a schematic cross-sectional view of the entire etching of the second LED epitaxial layer to expose the light exit surface of the first LED unit;

FIG. 12 is a schematic cross-sectional view of a process of forming a second LED unit on a second LED epitaxial layer;

FIG. 13 is a schematic cross-sectional structure after forming a second LED unit;

FIG. 14 is a schematic cross-sectional view of a bonding process of a third LED epitaxial layer to a drive substrate;

FIG. 15 is a schematic cross-sectional view of the third LED epitaxial layer bonded to the drive substrate with the substrate removed;

FIG. 16 is a schematic cross-sectional view of a process of etching the third LED epitaxial layer entirely to expose the light emitting surfaces of the first and second LED units;

FIG. 17 is a schematic cross-sectional view of a process of forming a third LED unit on a third LED epitaxial layer;

fig. 18 is a schematic cross-sectional structure after forming a third LED unit;

FIG. 19 is a schematic diagram of a front view of a full color pixel of a micro LED display device according to some embodiments of the present application;

reference numerals: 10-driving a substrate; 110-a first contact; 100-second contacts; 200-a light-emitting surface; 201-a first doping type semiconductor layer; 202-an active layer; 203-a second doped semiconductor layer; 210-a first LED epitaxial layer; 211-a first LED unit; 220-a second LED epitaxial layer; 221-a second LED unit; 230-a third LED epitaxial layer; 231-a third LED unit; 300-a bonding layer; 400-a first substrate; 401-a second substrate; 403-a third substrate; 500-a first mask protection layer; 501-a third mask protection layer; 600-a second mask protection layer; 700-a first avoidance hole; 710-a second escape aperture; 800-a common electrode layer; 900-passivation layer.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

In the description of the present application, it should be understood that the terms "on …," "over …," "over …," and "over …" should be interpreted in the broadest sense, meaning that the description containing these terms is to be interpreted as "the components may be disposed on another component in direct contact, or there may be intermediate components or layers between the components" in the description of the present application.

Furthermore, spatially relative terms such as "under …," "under …," "under …," "over …," "over …," "over …," "lower," "upper," and the like may also be used herein for ease of description to describe one element or component's relationship to another element or component as illustrated in the figures. In addition to the orientations depicted in the drawings, the spatially relative terms are intended to encompass different orientations of the device in use or operation. The device may be otherwise oriented (rotated 90 ° or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The term "layer" as used in this application refers to a portion of material that includes regions having a certain thickness. The layers may extend over the entire underlying or overlying structure, or may extend over a localized area of the underlying or overlying structure. Furthermore, the layer may be a region of homogeneous or heterogeneous continuous structure having a thickness less than the thickness of the continuous structure. For example, the layer may be located between the top and bottom surfaces of the continuous structure or between any pair of horizontal planes therebetween. The layers may extend horizontally, vertically and/or along a tapered surface. One layer may comprise multiple layers. For example, the semiconductor layer may include one or more doped or undoped semiconductor layers, and may have the same or different materials.

In the description of the present application, "micro" LEDs, "micro" devices are used to refer to descriptive dimensions of certain devices or structures according to embodiments of the present application. The term "micro" device or structure as used herein is intended to mean a scale of 110 nanometers to 110 micrometers. However, it should be appreciated that embodiments of the present invention are not necessarily limited thereto, and that certain aspects of the embodiments may be applicable to larger and possibly smaller dimensional scales.

The present embodiments describe micro led display devices and methods for making the same. The micro led display device of the present application uses micro leds (Micro light emitting diode, micro light emitting diode structures), the size of which is reduced to 110 nm to 110 μm. In micro LEDs, the micro LED array is highly integrated, and the distance of the LED units of the micro LEDs in the array is further reduced to 5 micrometers. The display mode of the micro LEDs is that the micro LEDs with the size of 5 microns or even smaller are connected to a driving substrate, so that the precise control of the light emitting brightness of each micro LED is realized. The preparation method of the embodiment of the application is suitable for a micro LED structure and is used for preparing micro LED display devices with micro dimensions.

Specifically, referring to fig. 1 and 2, the micro LED display device of the embodiment of the present application includes a driving substrate 10, a bonding layer 300, a first LED unit 211, and a second LED unit 221. Wherein the bonding layer 300 is disposed on the driving substrate 10, and the bonding layer 300 exposes a portion of the contacts; the first LED units 211 are arranged above the driving substrate 10 in an array, and the first LED units 211 are used for emitting light of a first color; the second LED units 221 are arranged above the driving substrate 10 in an array manner, and the second LED units 221 are disposed adjacent to the first LED units 211, and the second LED units 221 are configured to emit light of a second color; the first LED unit 211 and the second LED unit 221 can be independently driven by the driving substrate 10.

It can be appreciated that the micro LED display device emits the first color light through the first LED unit 211, the second LED unit 221 emits the second color light, and the color emitted by different LED units is directly utilized, so that full-color display is realized, no wavelength conversion layer is required to be integrated, the difficulty of preparation is reduced, the cost is reduced, and the yield of the micro LED display device is improved.

In some embodiments, the drive substrate 10 may comprise a semiconductor material, such as silicon, silicon carbide, silicon nitride, germanium, gallium arsenide, cobalt phosphide. In some embodiments, the drive substrate 10 may be made of a non-conductive material, such as glass, plastic, or sapphire wafers. In some embodiments, the driving substrate 10 may have a driving circuit formed therein, and the driving substrate 10 may be a CMOS (ComplementaryMetal Oxide Semiconductor ) back plate or a TFT glass substrate. The driving circuit supplies an electrical signal to the LED unit to control brightness. In some embodiments, the driving circuit may comprise an active matrix driving circuit, wherein each individual LED unit corresponds to an independent driver.

In some embodiments, the micro led display device further comprises: a plurality of third LED units 231, the third LED units 231 being arranged on the driving substrate 10 in an array, and being disposed adjacent to the first LED units 211, the second LED units 221, the third LED units 231 being configured to emit light of a third color; the third LED unit 231 can be independently driven by the driving substrate 10, and in particular, the third LED unit 231 is electrically connected to the contacts through the common electrode layer 800 and the bonding layer 300 so that the third LED unit 231 can be independently driven.

By providing the third LED unit 231 having a different emission color from the first and

second LED units

211 and 221, the color display range of the micro LED display device can be extended, and the display effect and application range of the micro LED display device can be improved.

In some embodiments, the driving substrate 10 includes a plurality of contacts, the plurality of contacts includes a first contact 110 and a second contact 100, the bonding layer 300 is made of a conductive material, the first doped semiconductor layer 201 of the first LED unit 211 is electrically connected to the first contact 110 through the bonding layer 300, the first doped semiconductor layer 201 of the second LED unit 221 is electrically connected to the first contact 110 through the bonding layer 300, and the second doped semiconductor layer 203 of the first LED unit 211 and the second doped semiconductor layer 203 of the second LED unit 221 are electrically connected to the second contact 100 through the common electrode layer 800.

In some embodiments, the driving substrate 10 includes a plurality of contacts including the first contact 110 and the second contact 100, and the first LED unit 211 and the second LED unit 221 each include a first doping type semiconductor layer 201, an active layer 202, and a second doping type semiconductor layer 203. The first doped semiconductor layer 201 is disposed on the bonding layer 300, and the first doped semiconductor layer 201 is electrically connected to the first contact 110 through the bonding layer 300; the active layer 202 is disposed on a side of the first doped semiconductor layer 201 facing away from the bonding layer 300, the second doped semiconductor layer 203 is disposed on a side of the active layer 202 facing away from the first doped semiconductor layer 201, and the second doped semiconductor layer 203 is electrically connected to the second contact 100 through the common electrode layer 800. That is, the active layer 202 is disposed between the first doped semiconductor layer 201 and the second doped semiconductor layer 203, and the light emitting surface 200 is located on top of the second doped semiconductor layer 203.

In some embodiments, the drive substrate 10 includes a plurality of contacts including a first contact 110 and a second contact 100; the bonding layer 300 is made of a conductive material, the first doped semiconductor layer 201 of the first LED unit 211 is electrically connected to the first contact 110 through the bonding layer 300, the first doped semiconductor layer 201 of the second LED unit 221 is electrically connected to the first contact 110 through the bonding layer 300, the first doped semiconductor layer 201 of the third LED unit 231 is electrically connected to the first contact 110 through the bonding layer 300, and the second doped semiconductor layer 203 of the first LED unit 211, the second doped semiconductor layer 203 of the second LED unit 221, and the second doped semiconductor layer 203 of the third LED unit 231 are electrically connected to the second contact 100 through the common electrode layer 800.

In some embodiments, the contacts include a first contact 110 and a second contact 100; the third LED unit 231 includes a first doping type semiconductor layer 201, an active layer 202, and a second doping type semiconductor layer 203. The first doped semiconductor layer 201 is disposed on the bonding layer 300, and the first doped semiconductor layer 201 is electrically connected to the first contact 110 through the bonding layer 300; the active layer 202 is disposed on a side of the first doped semiconductor layer 201 facing away from the bonding layer 300, the second doped semiconductor layer 203 is disposed on a side of the active layer 202 facing away from the first doped semiconductor layer 201, and the second doped semiconductor layer 203 is electrically connected to the second contact 100 through the common electrode layer 800. That is, the active layer 202 is disposed between the first doped semiconductor layer 201 and the second doped semiconductor layer 203, and the light emitting surface 200 is located on top of the second doped semiconductor layer 203.

It is understood that in embodiments of the present application, the connection structure of the micro leds may be co-cathodic or co-anodic or independent of each other.

For example, in the manner of fig. 2, one first contact 110 and one second contact 100 may be disposed corresponding to each LED unit, the first contact 110 is disposed under the corresponding LED unit in an aligned manner, the first doped semiconductor layer 201 of the LED unit is electrically connected to the corresponding first contact 110 through the bonding layer 300, the second contact 100 is disposed between adjacent LED units, and the second doped semiconductor layer 203 is electrically connected to the corresponding second contact 100. It is understood that the LED units include a first LED unit 211, a second LED unit 221, and a third LED unit 231.

For example, only one first contact 110 may be provided on the driving substrate 10, and the second contacts 100 corresponding to the number of LED units may be provided, the first doped semiconductor layer 201 of each LED unit is electrically connected to the first contact 110, and the second doped semiconductor layer 203 of each LED unit is electrically connected to the corresponding second contact 100.

For example, only one second contact 100 may be provided on the driving substrate 10, and the first contacts 110 corresponding to the number of LED units may be provided, the first doping type semiconductor layers 201 of the respective LED units are electrically connected to the corresponding first contacts 110, and the second doping type semiconductor layers 203 of the respective LED units are electrically connected to the second contacts 100.

It will be appreciated that the first contact 110 and the second contact 100 are of different polarity, one being an anode and the other being a cathode.

In some embodiments, the first, second, and third color light are each selected from: red light, green light, and blue light. The light emitting colors of the first LED unit 211, the second LED unit 221 and the third LED unit 231 are different from each other, which is advantageous to realize full-color display and make the color more plump. In some embodiments, the color may be any one of purple, yellow, and the like.

In some embodiments, the first LED unit 211, the second LED unit 221, and the third LED unit 231 have a size of 0.1-5 microns; the spacing between the adjacent first LED unit 211, second LED unit 221 and third LED unit 231 is 1-10 microns. Under this size, interval, the degree of difficulty of integrating wavelength conversion layer respectively is great, therefore this application has reduced the degree of difficulty of preparation by the luminous colour difference of LED unit itself by a wide margin.

In some embodiments, the at least one first LED unit 211, the at least one second LED unit 221, and the at least one third LED unit 231 form one full-color pixel of the micro LED display device. That is, one full color pixel of the micro LED display device may be composed of one first LED unit 211, one second LED unit 221, and one third LED unit 231, for example, RGB full color pixels may be composed by displaying three colors of red, green, and blue; alternatively, as shown in fig. 19, a full-color pixel of the micro LED display device may be composed of a first LED unit 211, two second LED units 221 and a third LED unit 231, and may be composed of RGBG, GRGB or RGGB full-color pixels by displaying one red, two green, one blue.

Correspondingly, the embodiment of the application also provides a preparation method of the micro LED display device, which comprises the following steps:

providing a driving substrate 10, a bonding layer 300 and a plurality of first LED units 211, wherein the bonding layer 300 is arranged on the driving substrate 10, the first LED units 211 are arranged above the driving substrate 10 in an array, and the first LED units 211 are used for emitting light of a first color;

providing a second LED epitaxial layer 220, wherein the second LED epitaxial layer 220 is provided with a plurality of first avoidance holes 700;

bonding the second LED epitaxial layer 220 with the driving substrate 10 and covering the first LED unit 211, wherein the position of the first avoidance hole 700 corresponds to the position of the first LED unit 211, and the depth of the first avoidance hole 700 is greater than the height of the first LED unit 211;

etching the second LED epitaxial layer 220 to form a plurality of second LED units 221, wherein the second LED units 221 are arranged on the driving substrate 10 in an array manner, and the second LED units 221 are used for emitting light of a second color;

the first LED unit 211 and the second LED unit 221 can be independently driven by the driving substrate 10.

It can be appreciated that in the preparation method of the micro LED display device, the first LED unit 211 and the second LED unit 221 are sequentially prepared, the first avoiding hole 700 is formed in the second LED epitaxial layer 220 skillfully during preparation, and the depth of the first avoiding hole 700 is larger than the height of the first LED unit 211, so that the second LED epitaxial layer 220 can be smoothly bonded with the driving substrate 10, and the second LED unit 221 is prepared by using an etching process, so that the preparation difficulty is reduced, and the yield of the micro LED display device is improved.

Specifically, referring to fig. 3, a driving substrate 10 is provided, where the driving substrate 10 includes a driving circuit and a plurality of contacts electrically connected to the driving circuit, and the plurality of contacts are a first contact 110 and a second contact 100 respectively. A bonding layer 300 is disposed on the driving substrate 10, and the bonding layer 300 may be metal or other conductive material, such as Au, sn, in, cu or Ti. The bonding layer 300 is used for a subsequent bonding process on the one hand, and for electrically connecting the first doping type semiconductor layer 201 on the other hand.

Referring to fig. 4, the step of providing the plurality of first LED units 211 includes:

the first LED epitaxial layer 210 is provided, the first LED epitaxial layer 210 is disposed on the first substrate 400, and a bonding metal is plated on a surface (i.e., the first doped semiconductor layer 201) of the first LED epitaxial layer 210 facing away from the first substrate 400 to form the bonding layer 300.

The first LED epitaxial layer 210 is bonded to the driving substrate 10 through the bonding layer 300, for example, high-pressure high-temperature bonding may be employed.

Referring to fig. 5, the first substrate 400 is removed from the bonded sample, and the second doped semiconductor layer 203 of the first LED epitaxial layer 210 is exposed.

Referring to fig. 6 and 7, the first LED units 211 are formed by masking, that is, the first mask protection layer 500 is formed on the first LED epitaxial layer 210, the first LED epitaxial layer 210 is blocked from being etched by the first mask protection layer 500, the plurality of first LED units 211 arranged in an array are formed above the driving substrate 10, and the first LED units 211 are electrically connected to the first contacts 110 through the bonding layer 300.

The second LED unit 221 is then prepared, specifically, the second LED epitaxial layer 220 is provided, and the step of bonding the second LED epitaxial layer 220 with the driving substrate 10 and covering the first LED unit 211 includes:

providing a second LED epitaxial layer 220, the second LED epitaxial layer 220 being disposed on a second substrate 401; the bonding layer 300 is formed by plating a bonding metal on the side of the second LED epitaxial layer 220 away from the second substrate 401 (i.e., the surface of the first doped semiconductor layer 201).

Referring to fig. 8, the bonding layer 300 and the second LED epitaxial layer 220 are etched through the second mask protection layer 600 to form a plurality of first avoidance holes 700, and the positions of the first avoidance holes 700 correspond to the positions of the first LED units 211.

Referring to fig. 9, the second LED epitaxial layer 220 is bonded to the driving substrate 10 using high temperature and high pressure, and the first avoiding hole 700 covers the first LED unit 211, i.e., the first avoiding hole 700 wraps (covers) the outer surface of the first LED unit 211. Specifically, the bonding may be performed by aligned bonding, or other bonding methods known in the art may be used.

Referring to fig. 10, the second substrate 401 is removed from the bonded sample, and the second doped semiconductor layer 203 of the second LED epitaxial layer 220 is exposed.

Then, the second LED epitaxial layer 220 is mask etched to form a plurality of second LED units 221, including the steps of:

for the case that the first avoiding hole 700 penetrates the second LED epitaxial layer 220, referring to fig. 12, the first mask protection layer 500 is directly formed over the second LED epitaxial layer 220 without thinning the second LED epitaxial layer 220, the first mask protection layer 500 shields the first LED unit 211, and the first mask protection layer 500 shields the region of the second LED epitaxial layer 220 for forming the second LED unit 221.

For the case that the first avoiding hole 700 does not penetrate the second LED epitaxial layer 220, referring to fig. 11, the second LED epitaxial layer 220 is etched on the whole surface first, so as to expose the light emitting surface 200 of the first LED unit 211. Referring to fig. 12, a first mask protection layer 500 is then formed over the second LED epitaxial layer 220, the first mask protection layer 500 shielding the first LED unit 211, and the first mask protection layer 500 shielding the second LED epitaxial layer 220 for forming the region of the second LED unit 221.

Referring to fig. 13, the second LED epitaxial layer 220 is then etched to form a second LED unit 221.

In some embodiments, when the third LED unit 231 is needed, the method for manufacturing the micro LED display device further includes a step of manufacturing the third LED unit 231, including: providing a third LED epitaxial layer 230, bonding the third LED epitaxial layer 230 with the driving substrate 10 and covering the first and

second LED units

211 and 221; etching the third LED epitaxial layer 230 to form a plurality of third LED units 231, wherein the third LED units 231 are arranged on the driving substrate 10 in an array manner and are adjacent to the first LED units 211 and the second LED units 221, and the third LED units 231 are used for emitting light of a third color; the third LED unit 231 is electrically connected to the contacts through the common electrode layer 800 and the bonding layer 300 so that the third LED unit 231 can be independently driven.

Specifically, the step of providing the third LED epitaxial layer 230, bonding the third LED epitaxial layer 230 to the driving substrate 10 and covering the first LED unit 211 and the second LED unit 221 includes:

providing a third LED epitaxial layer 230, the third LED epitaxial layer 230 being disposed on a third substrate 402; the bonding layer 300 is formed by plating a bonding metal on the side of the third LED epitaxial layer 230 facing away from the third substrate 402 (i.e., the surface of the first doped semiconductor layer 201). Then, similar to fig. 8, the bonding layer 300 and the third LED epitaxial layer 230 are etched using the second mask protection layer 600 to form a plurality of second escape holes 710 such that the positions of the second escape holes 710 correspond to the positions of the first LED units 211 and the second LED units 221, and the depths of the second escape holes 710 are greater than the heights of the first LED units 211 and the second LED units 221.

Referring to fig. 14, the third LED epitaxial layer 230 is aligned and bonded with the driving substrate 10 using high temperature and high pressure such that the second avoidance holes 710 cover the first LED units 211 and the second LED units 221; of course, other bonding means besides alignment bonding may be employed as known in the art.

Referring to fig. 15, the third substrate 402 is removed from the bonded sample, and the second doped semiconductor layer 203 of the third LED epitaxial layer 230 is exposed.

Then, the third LED epitaxial layer 230 is mask etched to form a plurality of third LED units 231, the steps including:

for the case that the second avoidance hole 710 penetrates the third LED epitaxial layer 230, referring to fig. 17, the third mask protection layer 501 is formed directly over the third LED epitaxial layer 230 without thinning the third LED epitaxial layer 230, the third mask protection layer 501 shields the first LED unit 211 and the second LED unit 221, and the third mask protection layer 501 shields the region of the third LED epitaxial layer 230 for forming the third LED unit 231.

For the case that the second avoiding hole 710 penetrates the third LED epitaxial layer 230, referring to fig. 16, the third LED epitaxial layer 230 is etched on the whole surface to expose the light emitting surfaces 200 of the first LED unit 211 and the second LED unit 221. Referring to fig. 17, a third mask protection layer 501 is then formed over the third LED epitaxial layer 230, the third mask protection layer 501 shields the first LED unit 211 and the second LED unit 221, and the third mask protection layer 501 shields the region of the third LED epitaxial layer 230 for forming the third LED unit 231.

Referring to fig. 18, the third LED epitaxial layer 230 is etched to form a third LED unit 231.

And then, carrying out subsequent preparation by using a micro LED process technology to form a complete micro LED display device.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

The micro led display device and the preparation method thereof provided by the embodiment of the present application are described in detail, and specific examples are applied to illustrate the principle and the implementation of the present application, and the description of the above embodiments is only used to help understand the technical scheme and the core idea of the present application; those of ordinary skill in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing a micro led display device, comprising:

providing a driving substrate (10), a bonding layer (300) and a plurality of first LED units (211), wherein the bonding layer (300) is arranged on the driving substrate (10), the first LED units (211) are arranged above the driving substrate (10) in an array manner, and the first LED units (211) are used for emitting first color light;

Providing a second LED epitaxial layer (220), wherein the second LED epitaxial layer (220) is provided with a plurality of first avoidance holes (700);

bonding the second LED epitaxial layer (220) with the driving substrate (10) and covering the first LED unit (211), wherein the position of the first avoidance hole (700) corresponds to the position of the first LED unit (211);

etching the second LED epitaxial layer (220) to form a plurality of second LED units (221) and exposing the first LED units (211), wherein the second LED units (221) are arranged above the driving substrate (10) in an array manner, and the second LED units (221) are used for emitting second color light;

the first LED unit (211) and the second LED unit (221) can be independently driven by the driving substrate (10).

2. The method of manufacturing a micro LED display device according to claim 1, wherein the step of providing a plurality of first LED units (211) comprises:

providing a first LED epitaxial layer (210), the first LED epitaxial layer (210) being disposed on a first substrate (400);

bonding the first LED epitaxial layer (210) to the drive substrate (10) through the bonding layer (300);

-removing the first substrate (400);

the first LED epitaxial layer (210) is etched, and a plurality of first LED units (211) arranged in an array are formed above the driving substrate (10).

3. The method of manufacturing a micro LED display device according to claim 1, wherein the step of providing a second LED epitaxial layer (220) comprises:

providing a second LED epitaxial layer (220), the second LED epitaxial layer (220) being disposed on a second substrate (401);

forming a bonding layer (300) on the second LED epitaxial layer (220), and etching the bonding layer (300) and the second LED epitaxial layer (220) to form a plurality of first avoidance holes (700);

-removing the second substrate (401) after bonding the second LED epitaxial layers (220) to the drive substrate (10).

4. The method of manufacturing a micro LED display device according to claim 1, wherein the step of etching the second LED epitaxial layer (220) to form a plurality of second LED units (221) and exposing the first LED units (211) comprises:

-forming a first mask protection layer (500) over the second LED epitaxial layer (220), the first mask protection layer (500) shielding the first LED unit (211), and the first mask protection layer (500) shielding a region of the second LED epitaxial layer (220) for forming the second LED unit (221);

The second LED epitaxial layer (220) is etched to form the second LED unit (221) and then the first mask protection layer (500) is removed.

5. The method of manufacturing a micro LED display device according to claim 4, further comprising, before forming the first mask protection layer (500) over the second LED epitaxial layer (220):

the second LED epitaxial layer (220) is thinned until the light exit face (200) of the first LED unit (211) is exposed.

6. The method of manufacturing a micro led display device according to claim 1, further comprising:

providing a third LED epitaxial layer (230), the third LED epitaxial layer (230) having a plurality of second relief holes (710) thereon;

bonding the third LED epitaxial layer (230) with the driving substrate (10) and covering the first LED unit (211) and the second LED unit (221), wherein the position of the second avoidance hole (710) corresponds to the positions of the first LED unit (211) and the second LED unit (221);

etching the third LED epitaxial layer (230) to form a plurality of third LED units (231) and exposing the first LED units (211) and the second LED units (221), wherein the third LED units (231) are arranged on the driving substrate (10) in an array manner, and the third LED units (231) are used for emitting third color light;

The third LED unit (231) can be independently driven by the driving substrate.

7. The method of manufacturing a micro led display device according to claim 6, wherein,

the step of providing a third LED epitaxial layer (230) comprises:

providing a third LED epitaxial layer (230), the third LED epitaxial layer (230) being disposed on a third substrate (402);

forming a bonding layer (300) on the third LED epitaxial layer (230), etching the bonding layer (300) and the third LED epitaxial layer (230) to form a plurality of the second relief holes (710);

-removing the third substrate (402) after bonding the third LED epitaxial layers (230) to the drive substrate (10).

8. The method of manufacturing a micro led display device according to claim 6, wherein,

the step of etching the third LED epitaxial layer (230) to form a plurality of third LED units (231) and exposing the first LED units (211) and the second LED units (221) includes:

-forming a third mask protection layer (501) over the third LED epitaxial layer (230), the third mask protection layer (501) shielding the first LED unit (211) and the second LED unit (221), and the third mask protection layer (501) shielding a region of the third LED epitaxial layer (230) for forming the third LED unit (231);

The third LED epitaxial layer (230) is etched to form the third LED unit (231) and then the third mask protection layer (501) is removed.

9. The method of manufacturing a micro LED display device according to claim 8, further comprising, before forming a third mask protection layer (501) over the third LED epitaxial layer (230):

thinning the third LED epitaxial layer (230) to expose light emitting surfaces (200) of the first LED unit (211) and the second LED unit (221).

10. The method of manufacturing a micro led display device according to claim 1, wherein,

the drive substrate (10) comprises a plurality of contacts including a first contact (110) and a second contact (100);

the bonding layer (300) is made of a conductive material, the first doped semiconductor layer (201) of the first LED unit (211) is electrically connected with the first contact (110) through the bonding layer (300), the first doped semiconductor layer (201) of the second LED unit (221) is electrically connected with the first contact (110) through the bonding layer (300), and the second doped semiconductor layer (203) of the first LED unit (211) and the second doped semiconductor layer (203) of the second LED unit (221) are electrically connected with the second contact (100) through the common electrode layer (800).

11. A micro led display device, comprising:

a drive substrate (10), the drive substrate (10) comprising a plurality of first contacts (110);

a bonding layer (300), wherein the bonding layer (300) is arranged on the driving substrate (10);

a plurality of first LED units (211), the first LED units (211) being arranged above the driving substrate (10) in an array, the first LED units (211) being for emitting light of a first color;

a plurality of second LED units (221), the second LED units (221) being arranged in an array on the driving substrate (10), the second LED units (221) being configured to emit light of a second color;

wherein the bonding layer (300) is made of conductive material; the first contact (110) is aligned below the first LED unit (211), the whole surface of the first doped semiconductor layer of the first LED unit (211) is attached to the bonding layer (300) and is electrically connected with the aligned first contact (110) through the bonding layer (300); the first contact (110) is aligned below the second LED unit (221), and the whole surface of the first doped semiconductor layer of the second LED unit (221) is attached to the bonding layer (300) and is electrically connected with the aligned first contact (110) through the bonding layer (300);

The first LED unit (211) and the second LED unit (221) can be driven independently from the first contact (110) arranged in alignment therewith.

12. The micro led display device of claim 11, further comprising:

a plurality of third LED units (231), the third LED units (231) being arranged in an array on the drive substrate (10), the third LED units (231) being for emitting light of a third color;

the third LED unit (231) can be independently driven by the driving substrate (10).

13. The micro led display device according to claim 11, wherein the drive substrate (10) further comprises a second contact (100);

the second doped semiconductor layer (203) of the first LED unit (211) and the second doped semiconductor layer (203) of the second LED unit (221) are electrically connected to the second contact (100) via a common electrode layer (800).

14. The micro led display device according to claim 12, wherein the drive substrate (10) further comprises a second contact (100);

the lower part of the third LED unit (231) is aligned with the first contact (110), the whole surface of the first doped semiconductor layer (201) of the third LED unit (231) is attached to the bonding layer (300) and is electrically connected with the aligned first contact (110) through the bonding layer (300), and the second doped semiconductor layer (203) of the first LED unit (211), the second doped semiconductor layer (203) of the second LED unit (221) and the second doped semiconductor layer (203) of the third LED unit (231) are electrically connected with the second contact (100) through the common electrode layer (800).

15. The micro led display device of claim 12, wherein the first color light, the second color light, and the third color light are each selected from the group consisting of: red light, green light, and blue light.

16. The micro LED display device according to claim 11, wherein the first LED unit (211) and the second LED unit (221) have a size of 0.1-5 micrometers; the distance between the adjacent first LED units (211) and the adjacent second LED units (221) is 1-10 microns.

17. The micro LED display device according to claim 12, wherein the first LED unit (211), the second LED unit (221), the third LED unit (231) have a size of 0.1-5 micrometers; the distance between the adjacent first LED units (211), second LED units (221) and third LED units (231) is 1-10 micrometers.

18. The micro LED display device according to claim 11, wherein the sides of the first LED unit (211) and the second LED unit (221) are provided with a passivation layer (900).

19. The micro LED display device according to claim 12, wherein the sides of the first LED unit (211), the second LED unit (221) and the third LED unit (231) are provided with passivation layers (900).

20. The micro LED display device according to claim 12, wherein at least one of the first LED unit (211), at least one of the second LED unit (221) and at least one of the third LED unit (231) form one full color pixel point of the micro LED display device.