JPWO2021196817A5 - - Google Patents

Description

(Related application)
This application claims priority to the Chinese patent application with application number 202010262697.5 filed on April 3, 2020 as the basic application, the entire content of which is incorporated into this application by reference.

The present disclosure relates to the field of display technology, and particularly relates to an inorganic light emitting diode substrate, a method for manufacturing the same, and an inorganic light emitting diode display device.

In the field of display technology, Micro Light-Emitting Diode (Micro LED) display technology is a technology for miniaturizing and matrix-forming light-emitting diodes. Micro-light-emitting diode display device has the advantages of high resolution, energy saving, high brightness, high sharpness, high color saturation, relatively fast response speed, long life span, etc., and has excellent application prospects.

In one embodiment, an inorganic light emitting diode substrate includes a base, a plurality of epitaxial layer structures, a passivation layer, and a plurality of second electrodes. Here, the base includes a base substrate and a plurality of first electrodes provided on the base substrate . A plurality of epitaxial layer structures are provided on the base, and the plurality of epitaxial layer structures are spaced apart. Each of the first electrodes is coupled to one epitaxial layer structure. The passivation layer is made of photoresist. The passivation layer covers the surfaces of the plurality of epitaxial layer structures remote from the base and fills the gaps between the plurality of epitaxial layer structures. The passivation layer has a plurality of via holes. A plurality of second electrodes are provided on a side of the passivation layer remote from the base, each of the second electrodes being coupled to one epitaxial layer structure through at least one via hole.

In some embodiments, the passivation layer has a first portion and a second portion. The first portion covers a surface of the plurality of epitaxial layer structures remote from the base, and the second portion fills gaps between the plurality of epitaxial layer structures. With respect to a surface of the base on which a first electrode is provided , a surface of the first portion remote from the base is flush or substantially flush with a surface of the second portion remote from the base.

In some embodiments, the ratio of the thickness of the first portion of the passivation layer to the thickness of the epitaxial layer structure ranges from 1:1 to 3:1.

In some embodiments, the passivation layer is comprised of an epoxy-based photoresist.

In some embodiments, each epitaxial layer structure includes a first semiconductor layer, a light emitting layer, and a second semiconductor layer provided in a stack. The light emitting layer is located between the first semiconductor layer and the second semiconductor layer. Here, in the epitaxial layer structure, the first semiconductor layer is closer to the base than the light emitting layer and the second semiconductor layer. Each of the first electrodes is coupled to a first semiconductor layer in one epitaxial layer structure, and each of the second electrodes is coupled to a second semiconductor layer in one epitaxial layer structure through at least one via hole. Ru.

In some embodiments, the base includes the base substrate, a driving circuit, and a plurality of first electrodes. The drive circuit is provided on the base substrate. The plurality of first electrodes are provided on a side of the drive circuit remote from the base substrate, and the plurality of first electrodes are coupled to the drive circuit.

In another aspect, a method of manufacturing an inorganic light emitting diode substrate is provided, the method comprising: providing a base including a plurality of first electrodes and a plurality of epitaxial layer structures, each of the epitaxial layer structures having one first electrode; transferring the plurality of epitaxial layer structures to the base so as to be coupled to one electrode; a photoresist film covering a surface of the plurality of epitaxial layer structures remote from the base; forming the photoresist film on a side remote from the base of the plurality of epitaxial layer structures so as to fill gaps between the epitaxial layer structures; and patterning the photoresist film to form the photoresist film. forming a plurality of via holes in the passivation layer to obtain a passivation layer, forming a plurality of second electrodes on a side of the passivation layer remote from the base, and connecting each of the second electrodes to one via at least one via hole; and bonding to the epitaxial layer structure.

In some embodiments, the step of patterning the photoresist film to form a plurality of via holes in the photoresist film to obtain a passivation layer may be performed on a side of the photoresist film remote from the base. providing a mask on the photoresist film, performing an exposure and development process on the photoresist film to form a plurality of via holes in the photoresist film, and curing the photoresist film in which the plurality of via holes are formed. , obtaining and having a passivation layer.

In some embodiments, forming the photoresist film on a side remote from the base of the plurality of epitaxial layer structures described above may include forming the photoresist film on a side remote from the base of the plurality of epitaxial layer structures . spin coating a photoresist on a side of the plurality of epitaxial layer structures remote from the base so as to cover a side surface and fill a gap between the plurality of epitaxial layer structures; precuring to form a photoresist film.

In some embodiments, the method for manufacturing an inorganic light emitting diode substrate further includes forming the plurality of via holes by a plasma process before forming the plurality of first electrodes on a side of the passivation layer remote from the base. The method further includes performing a residue removal process on the photoresist film, thereby removing the photoresist film remaining in the plurality of via holes after the photoresist film is developed.

In another aspect, an inorganic light emitting diode display device is provided, the inorganic light emitting diode display device comprising the above inorganic light emitting diode substrate and a sealing substrate provided on one side of the inorganic light emitting diode substrate.

In order to more clearly explain the technical solution of the present disclosure, the following briefly describes the drawings necessary for explaining some embodiments of the present disclosure. It is clear that the drawings in the following description are merely illustrations of some embodiments of the disclosure. Those skilled in the art can derive other drawings from these drawings. Also, the drawings in the following description may be considered as schematic illustrations and are not intended to limit the actual dimensions of the product, the actual process of the method, the actual sequence of signals, etc., according to the embodiments of the present disclosure.
1 is a structural diagram of an inorganic light emitting diode substrate according to some embodiments of related technology; FIG. FIG. 3 is a structural diagram of an inorganic light emitting diode substrate according to some embodiments of the present disclosure. FIG. 4 is a structural diagram of another inorganic light emitting diode substrate according to some embodiments of the present disclosure; FIG. 3 is a structural diagram of yet another inorganic light emitting diode substrate according to some embodiments of the present disclosure. FIG. 3 is a structural diagram of yet another inorganic light emitting diode substrate according to some embodiments of the present disclosure. FIG. 3 is a top view of an inorganic light emitting diode substrate according to some embodiments of the present disclosure. 3 is a flowchart of a method for manufacturing an inorganic light emitting diode substrate according to some embodiments of the present disclosure. 3 is a flowchart of another method for manufacturing an inorganic light emitting diode substrate according to some embodiments of the present disclosure. 3 is a flowchart of yet another method of manufacturing an inorganic light emitting diode substrate according to some embodiments of the present disclosure. 3 is a flowchart of yet another method of manufacturing an inorganic light emitting diode substrate according to some embodiments of the present disclosure. 1 is a structural diagram of an inorganic light emitting diode display device according to some embodiments of the present disclosure; FIG. FIG. 3 is a focused ion beam microscopy view of an inorganic light emitting diode substrate according to some embodiments of the present disclosure.

Hereinafter, technical solutions in some embodiments of the present disclosure will be clearly and completely explained with reference to the drawings. Obviously, the described embodiments are only some, but not all, embodiments of the present disclosure. All other examples that come to those skilled in the art based on the examples provided by this disclosure are intended to be within the scope of the claims of this disclosure.

Unless the context otherwise requires, throughout this specification and claims the term "comprise" and other forms, such as the third-person singular "comprises" and the present The participial form "comprising" is to be interpreted in an open, inclusive sense, ie, "including, but not limited to." In the description herein, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", “Specific examples” or “some examples” or the like refers to examples in which the example, or a particular feature, structure, material, or characteristic associated with the example, is present in at least one of the disclosures. is intended to include one embodiment or example. The schematic representations of the terms above do not necessarily refer to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics described may be included in any one or more embodiments or examples in any suitable manner.

In the following, the terms "first" and "second" are used for descriptive purposes only and are to be understood as stating or implying relative importance or implying the number of technical features shown. Shouldn't. Accordingly, a feature defined as "first" or "second" may explicitly or implicitly include one or more of those features. In describing embodiments of the present disclosure, "plurality" means two or more, unless otherwise specified.

In describing some embodiments, "coupling" and "connecting" and expressions derived therefrom may be used. For example, in the description of some embodiments, the term "connected" may be used to indicate that two or more components are in direct physical or electrical contact with each other. As another example, the term "coupled" may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. However, the term "coupled" or "communicatively coupled" also means that two or more components are not in direct contact with each other, but still cooperate or interact with each other. obtain. The embodiments disclosed herein are not necessarily limited to the content of this specification.

Example embodiments are described herein with reference to cross-sectional and/or plan views that are idealized example drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Variations in shape relative to the drawings may therefore be expected due to, for example, manufacturing techniques and/or tolerances. Therefore, the exemplary embodiments are not limited to the shapes of the regions shown in this disclosure, but should be construed to include shape variations due to manufacturing and the like. For example, etched regions shown as rectangular typically have curved features. Accordingly, the regions illustrated in the drawings are exemplary in nature, and their shapes are not intended to represent the actual shapes of the regions of the device, but rather to limit the scope of the example embodiments. It is not intended to.

The micro-light emitting diode display includes a base and a plurality of micro-epitaxial layer structures provided on the base. The plurality of microepitaxial layer structures may be arranged in an array, and the distance between adjacent microepitaxial layer structures may be on the order of microns to achieve high resolution display.

In the manufacturing of micro-light emitting diode display devices, after transferring the multiple epitaxial layer structures to the base and bonding the multiple epitaxial layer structures to the anode on the base, passivation is applied to insulate between the multiple epitaxial layer structures. It is necessary to create a membrane . Next, a via hole is created in the passivation film to obtain a passivation layer . A cathode is then fabricated in the passivation layer and coupled to the epitaxial layer structure through via holes in the passivation layer.

Conventionally, inorganic materials such as silicon dioxide have been used to form passivation layers. As shown in FIG. 1, in the inorganic light emitting diode substrate 01', the passivation layer 3' is usually manufactured by a deposition process, so the thickness of the passivation layer 3' at each position is relatively uniform, and the thickness of the passivation layer 3' at each position is relatively uniform. The parts of the passivation layer 3' that cover the layer structure 2 protrude more than the parts of the passivation layer 3' that are located in the gaps between the epitaxial layer structures 2. When the thickness of the passivation layer 3' is relatively small, the passivation layer tends to crack at the corner of the epitaxial layer structure 2 on the side away from the base 1 (see the circled part 3c in FIG. 1). Electrical leakage occurs. If the thickness of the passivation layer 3' is increased, the stress of the inorganic material such as silicon dioxide is large, so peeling of the passivation layer becomes a problem, and there is also a risk of electric leakage occurring.

Additionally, deposition and etching processes are required to form the passivation layer with silicon dioxide and to form via holes in the passivation layer. For example, first deposit a silicon dioxide film, then form a barrier layer with a via hole pattern on the silicon dioxide film, and then etch the silicon dioxide film to form the via holes. The manufacturing procedure is complicated and requires PECVD (plasma enhanced chemical vapor deposition) equipment and RIE/ICP etching (RIE: Reactive Ion Etching, ICP: Inductive). ly Coupled Plasma, inductively coupled plasma Etching) equipment is required, which increases manufacturing costs.

Some embodiments of the present disclosure provide an inorganic light emitting diode substrate 01. As shown in FIGS. 2A to 4 and 11, the inorganic light emitting diode substrate 01 includes a base 1, a plurality of epitaxial layer structures 2, a passivation layer 3, and a plurality of second electrodes 4.

Here, the base 1 includes a base substrate 11 and a plurality of first electrodes 12 provided on the base substrate 11 , and the plurality of epitaxial layer structures 2 are provided on the base 1 and include the plurality of epitaxial layer structures 2. are placed at intervals. One epitaxial layer structure 2 is coupled to each of the first electrodes 12 .

Passivation layer 3 is made of photoresist. The passivation layer 3 covers the surface of the plurality of epitaxial layer structures 2 on the side remote from the base 1, and the passivation layer 3 fills the gaps between the plurality of epitaxial layer structures 2, e.g. 2 includes a gap between two adjacent epitaxial layer structures 2 and a gap between four adjacent epitaxial layer structures 2 . As shown in FIG. 2B, the passivation layer 3 is provided with a plurality of via holes 3v.

A plurality of second electrodes 4 are provided on the side of the passivation layer 3 remote from the base 1, and each of the second electrodes 4 is coupled to one epitaxial layer structure 2 through at least one via hole 3v. As shown in FIG. 2B, each of the second electrodes 4 is coupled to one epitaxial layer structure 2 through one via hole 3v.

As an example, the first electrode 12 is one of an anode and a cathode, and the second electrode 4 is the other of an anode and a cathode. The first electrode 12 and the second electrode 4 are configured to supply a voltage to the epitaxial layer structure 2 and cause the epitaxial layer structure 2 to emit light when driven by the voltage.

In the inorganic light emitting diode substrate 01 according to some embodiments of the present disclosure, photoresist is used as the material of the passivation layer 3. During the manufacturing process of the passivation layer 3, the photoresist can fill the gaps between two or more adjacent epitaxial layer structures 2 during the photoresist application process due to its fluidity. Thereby, the formed passivation layer 3 can cover the surface of the plurality of epitaxial layer structures 2 on the side away from the base 1, and can fill the gaps between the plurality of epitaxial layer structures 2. . Therefore, the surface of the passivation layer 3 on the side away from the base 1 is relatively flat. In this way, it is possible to avoid the problem that the passivation layer 3 is prone to cracking at the corners of the epitaxial layer structure remote from the base 1, thereby eliminating the problem of leakage caused by this.

Furthermore, since the photoresist is an organic material and has better adhesion than inorganic materials such as silicon dioxide, the passivation layer 3 does not have the problem of peeling.

By performing an exposure and development process on the film layer made of photoresist, a plurality of via holes 3v can be formed in the photoresist film, and a passivation layer 3 is obtained. Equipment costs are relatively low because the exposure and development processes are relatively simple. Therefore, the embodiments of the present disclosure do not require the deposition and etching processes conventionally used to fabricate the passivation layer 3' with silicon dioxide, and therefore do not require expensive deposition and etching equipment. There is no need to use it, which simplifies the manufacturing process and saves manufacturing costs.

Furthermore, the light extraction efficiency of the epitaxial layer structure 2 is related to the refractive index of the passivation layer 3. At the interface between the epitaxial layer structure 2 and the passivation layer 3, if the incident angle of the light emitted from the epitaxial layer structure 2 is larger than the critical angle of total reflection, a total internal reflection phenomenon occurs, and the light enters the epitaxial layer structure 2. It is reflected back and cannot be emitted. Therefore, the larger the total reflection critical angle, the larger the amount of emitted light, and the higher the light extraction efficiency of the epitaxial layer structure 2. As can be seen from the formula for calculating the critical angle of total reflection θ sin θ=n ₂ /n ₁ , where n ₂ is the refractive index of the optically sparse medium (here, the refractive index of the passivation layer 3), and n ₁ is The refractive index of an optically dense medium (in this case, the refractive index of the film layer in contact with the passivation layer 3 in the epitaxial layer structure 2), and when n ₁ is constant, the critical angle of total reflection θ increases as n ₂ increases. growing. When using a photoresist having a relatively high refractive index (higher refractive index than silicon dioxide) as a material for the passivation layer, for example, when using an epoxy photoresist, in the present disclosure, the passivation layer 3 formed of the photoresist is The corresponding total internal reflection critical angle is larger than the corresponding total internal reflection critical angle for a passivation layer formed of silicon dioxide. In this way, in the inorganic light emitting diode substrate 01 according to the present disclosure, more of the light emitted from the epitaxial layer structure 2 can be transmitted through the passivation layer 3 and emitted. This is advantageous in improving the extraction efficiency, and in turn, it is advantageous in improving the light emitting efficiency of the inorganic light emitting diode substrate 01.

Note that in the inorganic light emitting diode substrate 01 shown in FIG. 2A, depending on process factors, the sidewalls of each film layer of the epitaxial layer structure may form an angle with respect to the surface of the base substrate 11 on which the first electrode 12 is provided . . For example, the shape of the cross section of each film layer of the epitaxial layer structure perpendicular to the surface of the base substrate 11 on which the first electrode 12 is provided is a trapezoid. As an example, a method for manufacturing a plurality of epitaxial layer structures 2 in an inorganic light emitting diode substrate 01 includes sequentially growing the entire film layer for forming an epitaxial layer structure on a silicon base, and The entire film layer is laid down on the base 1 together with the silicon base, the silicon base is removed, and the entire film layer remaining on the base 1 is patterned by an etching process to form a multiple epitaxial layer structure. 2 and having. During the etching process, the area where the membrane layer away from base 1 is etched is larger than the area where the membrane layer close to base 1 is etched, so that in the finally formed epitaxial layer structure, the area from base 1 to The area of the distant membrane layers is smaller than the area of the membrane layers closer to the base 1, which allows the shape of the cross-section of each membrane layer of the epitaxial layer structure 2 perpendicular to the surface on which the first electrode 12 of the base substrate 11 is provided. becomes a trapezoid.

For convenience of explanation, in the inorganic light emitting diode substrate 01 shown in FIGS. 2B to 4, the sidewalls of each film layer of the epitaxial layer structure are shown perpendicular to the base substrate, but the inorganic light emitting diode substrate 01 according to the present disclosure The structure of the diode substrate 01 is not limited to this.

FIG. 11 can be considered to be a focused ion beam micrograph of a cross section of the inorganic light emitting diode substrate 01 cut along the cutting line BB' in FIG. FIG. 11 shows the position and thickness of the membrane layers including the first electrode 12, the epitaxial layer structure 2, the passivation layer 3 and the second electrode 4. FIG. Since the cutting line BB' is not cut at the position where the via hole 3v is located, the via hole 3v of the passivation layer 3 is not visible in FIG.

In some embodiments, as shown in FIG. 2B, the passivation layer 3 includes a first portion 3a and a second portion 3b. The first portion 3a covers the surface of the plurality of epitaxial layer structures 2 on the side remote from the base substrate 11, and the second portion 3b fills the gaps between the plurality of epitaxial layer structures 2. With respect to the surface of the base substrate 11 on which the first electrode 12 is provided , the surface of the first portion 3a away from the base substrate 11 is flush with or almost flush with the surface of the second portion 3b remote from the base substrate 11. It is.

Due to the fluidity of the photoresist, during the process of applying the photoresist, the photoresist can fill the gaps between adjacent epitaxial layer structures 2, thereby allowing the first part of the formed passivation layer 3 to The surfaces of the second portions 3a and 3b that are away from the base substrate 11 are flush or substantially flush with the surface of the base substrate 11 on which the first electrode 12 is provided . In this way, the flatness of the surface of the passivation layer 3 can be ensured, and it is possible to avoid the problem of the passivation layer 3 cracking at the corner of the surface away from the base 1 of the epitaxial layer structure 2, which causes electrical leakage. .

In some embodiments, when setting the thickness of the passivation layer 3, the first part 3a of the passivation layer 3 completely covers the surface of the epitaxial layer structure 2, and the second part 3b covers the plurality of epitaxial layer structures 2. It is necessary to fill the gap between the base substrate 11 and the surface of the first portion 3a and the second portion 3b of the passivation layer 3 that is remote from the base substrate 11 is provided with the first electrode 12 of the base substrate 11. It should be taken into consideration that the passivation layer 3 needs to be flush with or almost flush with the surface , and the thickness of the passivation layer 3 is the same as that of the via hole 3v in the passivation layer 3 and the second electrode 4 located on the passivation layer 3. Since the influence on the ease of manufacturing should also be considered, it is necessary to appropriately set the thickness of the passivation layer 3.

In some examples, as shown in FIG. 2B, the thickness d ₁ of the first portion 3a of the passivation layer 3 increases the difficulty of the manufacturing process of the via hole 3v, making it difficult to connect the semiconductor layer in the epitaxial layer structure 2. In order to avoid affecting the ohmic contact with the second electrode 4, it cannot be made too large. Further, the thickness _d1 of the first portion 3a of the passivation layer 3 cannot be made too small in order to sufficiently fulfill the role of insulation. By way of example, the ratio range between the thickness d ₁ of the first portion 3a of the passivation layer 3 and the thickness of the epitaxial layer structure 2 is between 1:1 and 3:1. For example, if the thickness of the epitaxial layer structure 2 is 1 μm, the thickness d ₁ of the first portion 3a may be between 1 μm and 3 μm.

As shown in FIG. 2B, the thickness d ₁ of the first portion 3a of the passivation layer 3 ranges from 1 μm to 2 μm. For example, the thickness _d1 of the first portion 3a of the passivation layer 3 is 2 μm. The thickness d 2 of the second portion 3b of the passivation layer ₃ ranges from 2 μm to 4 μm, for example, the thickness d ₂ of the second portion 3b of the passivation layer 3 is 3 μm. It is understood that the difference between the thickness d ₂ and the thickness d ₁ is the thickness of the epitaxial layer structure 2 .

In order to make the surfaces of the first portion 3a and the second portion 3b of the passivation layer 3 that are remote from the base substrate 11 flush with the surface of the base substrate 11 on which the first electrode 12 is provided , the second portion of the passivation layer 3 is The thickness d ₂ of the part 3b should be the sum of the thickness d ₁ of the first part 3a and the thickness of the epitaxial layer structure 2, and if the thickness of the epitaxial layer structure 2 is 1 μm, the passivation layer 3 The thickness of the first portion 3a is 2 μm, and the thickness of the second portion 3b is 3 μm. In this way, it can be ensured that the surface of the passivation layer 3 is relatively flat and that the thickness of the first portion 3a of the passivation layer 3 can be moderate. As a result, it is advantageous for manufacturing the via hole 3v and the second electrode 4, and the passivation layer is not easily peeled off, so that no leakage phenomenon occurs.

In some embodiments, as shown in FIGS. 2B to 4, each epitaxial layer structure 2 includes a first semiconductor layer 21, a light emitting layer 22, and a second semiconductor layer 23 provided in a stack. The light emitting layer 22 is located between the first semiconductor layer 21 and the second semiconductor layer 23. As an example, the light emitting layer 22 has a quantum well structure.

Here, in the epitaxial layer structure 2, the first semiconductor layer 21 is closer to the base substrate 11 than the light emitting layer 22 and the second semiconductor layer 23. Each of the first electrodes 12 is coupled to a first semiconductor layer 21 within one epitaxial layer structure 2 . Each of the second electrodes 4 is coupled to the second semiconductor layer 23 in one epitaxial layer structure 2 through at least one via hole 3v.

In some embodiments, first semiconductor layer 21 is an N-type semiconductor layer. For example, the first semiconductor layer 21 is made of N-type gallium nitride (n-GaN). The second semiconductor layer 23 is a P-type semiconductor layer. For example, the second semiconductor layer 23 is made of P-type gallium nitride (p-GaN). Correspondingly, the first electrode 12 is a cathode, the second electrode 4 is an anode, the first semiconductor layer 21 of each epitaxial layer structure 2 is coupled to the cathode , and the second semiconductor layer of each epitaxial layer structure 2 is connected to the cathode. 23 is coupled to an anode through a via hole 3v , the anode supplies a positive voltage to the second semiconductor layer 23 , and the cathode supplies a negative voltage to the first semiconductor layer 21 . Thereby, electrons and holes are transported from the first semiconductor layer 21 and the second semiconductor layer 23 to the light-emitting layer 22, and the electrons and holes are recombined in the light-emitting layer 22, thereby realizing light emission.

In another example, the first semiconductor layer 21 is a P-type semiconductor layer. For example, the first semiconductor layer 21 is made of P-type gallium nitride (p-GaN). The second semiconductor layer 23 is an N-type semiconductor layer. For example, the second semiconductor layer 23 is made of N-type gallium nitride (n-GaN). Correspondingly, the first electrode 12 is an anode, the second electrode 4 is a cathode, the first semiconductor layer 21 of each epitaxial layer structure 2 is coupled to the anode, and the second semiconductor layer 23 is connected through the via hole 3v. Coupled to the cathode, the anode supplies a positive voltage to the first semiconductor layer 21 and the cathode supplies a negative voltage to the second semiconductor layer 23 . Thereby, electrons and holes are transported from the second semiconductor layer 23 and the first semiconductor layer 21 to the light-emitting layer 22, and the electrons and holes are recombined in the light-emitting layer 22, thereby realizing light emission.

In some embodiments, the passivation layer 3 consists of an epoxy-based photoresist.

The refractive index of SU-8 photoresist, which is an epoxy-based photoresist, is 1.6, the refractive index of silicon dioxide is 1.465, and the refractive index of epoxy-based photoresist is higher. Using an epoxy photoresist to form the passivation layer 3 is advantageous in increasing the light extraction efficiency of the epitaxial layer structure 2.

For example, when the epitaxial layer structure 2 includes a first semiconductor layer 21 , a light emitting layer 22 , and a second semiconductor layer 23 provided in a stacked manner, the passivation layer 3 is separated from the base substrate 11 of the second semiconductor layer 23 . The surface is covered, and the contact surface between the passivation layer 3 and the second semiconductor layer 23 becomes a total reflection boundary surface. In an example where the second semiconductor layer 23 is made of gallium nitride and the size of the single epitaxial layer structure 2 is 10 μm x 10 μm x 1 μm, the refractive index of gallium nitride is 2.5, so the total reflection critical angle θ is As can be seen from the calculation formula sin θ=n ₂ /n ₁ , when silicon dioxide is used as the material for the passivation layer 3, the critical angle of total reflection is 35.8°, and when the passivation layer 3 is made of silicon dioxide, the critical angle of total reflection is 35.8 In the case of the material, the critical angle of total reflection is 39.8°. Therefore, the critical angle of total reflection corresponding to the epoxy photoresist is relatively large, which is advantageous for increasing the light extraction efficiency of the epitaxial layer structure 2.

Based on the above premise, and without considering light absorption by the material, the inventors of the present disclosure have found that when silicon dioxide is used as the material of the passivation layer 3, a single epitaxial layer is formed using Monte Carlo ray tracing method. It has been found that the light extraction efficiency of structure 2 is about 84%, and when an epoxy photoresist is used as the material for the passivation layer 3, the light extraction efficiency of the single epitaxial layer structure 2 is about 89%, Accordingly, the light extraction efficiency of the single epitaxial layer structure 2 in the inorganic light emitting diode substrate 01 according to the present disclosure is improved by about 5%, which is advantageous for improving the light extraction efficiency of the entire inorganic light emitting diode substrate 01.

In addition to the above advantages, epoxy-based photoresists have low absorbance in the near-ultraviolet region. Therefore, in the epoxy photoresist, the amount of light transmitted in the near-ultraviolet region is large, the attenuation of the light intensity at different positions of the photoresist is relatively small, and the exposure of the entire photoresist layer is uniform. As a result, the plurality of via holes 3v obtained by subjecting a photoresist film layer formed of an epoxy photoresist to exposure and development processes have excellent uniformity. In addition, the epoxy photoresist has excellent mechanical properties, chemical corrosion resistance, and thermal stability, and is advantageous in increasing the stability and impact resistance of the formed inorganic light emitting diode substrate 01.

In some embodiments, as shown in FIG. 3, the base 1 includes a base substrate 11, a driving circuit 13, and a plurality of first electrodes 12. Here, the drive circuit 13 is provided on the base substrate 11, the plurality of first electrodes 12 are provided on the side of the drive circuit 13 remote from the base substrate 11, and the plurality of first electrodes 12 are provided on the drive circuit 13. The drive circuit 13 is configured to provide electrical signals to the plurality of first electrodes 12 . Thereby, the first electrode 12 and the second electrode 4 supply voltage to the epitaxial layer structure 2 coupled to the first electrode 12 and the second electrode 4 , and drive the driving epitaxial layer structure 2 to emit light. Can be done.

In some embodiments, as shown in FIG. 3, the inorganic light emitting diode substrate 01 according to the present disclosure adopts an active driving method. The plurality of first electrodes 12 are arranged in an array, and the plurality of first electrodes 12 are insulated by the passivation layer 3. The first electrode 12 is an anode and the second electrode 4 is a cathode. Each of the first electrodes 12 is coupled to one drive circuit 13, and the plurality of second electrodes 4 are coupled to each other to form one entire cathode layer.

In one example, the drive circuit includes a plurality of thin film transistors and at least one storage capacitor. The drive circuit supplies a positive voltage to the first electrode, the first electrode supplies a positive voltage to the epitaxial layer structure 2, and the second electrode supplies a negative voltage to the epitaxial layer structure 2. , thereby controlling the light emission of the epitaxial layer structure 2.

In another embodiment, the inorganic light emitting diode substrate 01 according to the present disclosure adopts a passive driving method. The plurality of first electrodes 12 are arranged in an array, the first electrodes 12 in the same row or column are coupled together, and the second electrodes 4 in the same column or row are coupled together.

As an example, as shown in FIGS. 4 and 5, FIG. 4 is a cross-sectional view taken along cutting line AA' of the inorganic light emitting diode substrate 01 of FIG. 5, and the plurality of first electrodes 12 are arranged in an array. The first electrodes 12 of the same row are combined into an integral structure so as to form one first electrode strip 12', and the second electrodes 4 of the same column are combined into one second electrode strip 12'. 4' to form a unitary structure . Two adjacent first electrode strips 12' are insulated by a passivation layer 3, and two adjacent second electrode strips 4' are insulated by a passivation layer 3. In the overlapping region of the first electrode strip 12' and the second electrode strip 4', an epitaxial layer structure 2 is provided. In the region where the plurality of first electrode strips 12' and the plurality of second electrode strips 4' overlap, the epitaxial layer structure 2 is driven by the voltage of the plurality of first electrode strips 12' and the plurality of second electrode strips 4'. Emits light. For example, the plurality of first electrode strips 12' are anode strips and the plurality of second electrode strips 4' are cathode strips.

In some examples, it is connected to an external drive circuit using a method such as COG (Chip On Glass) or TAB (Tape Automated Bonding). The drive circuit is coupled to the plurality of first electrode strips 12' and the plurality of second electrode strips 4', and the drive circuit applies a drive voltage to the plurality of first electrode strips 12' and the plurality of second electrode strips 4' . It is configured to supply the plurality of epitaxial layer structures 2 to emit light.

As shown in FIG. 6, some embodiments of the present disclosure further provide a method of manufacturing an inorganic light emitting diode substrate 01. The manufacturing method includes the following steps S1 to S6.

In S1, a base 1 and a plurality of epitaxial layer structures 2 are provided, where the base 1 includes a plurality of first electrodes 12.

The base 1 includes a base substrate 11 and a plurality of first electrodes 12 provided on the base substrate 11. For example, the plurality of first electrodes 12 are arranged in an array.

In some examples, epitaxial layer structure 2 is manufactured as follows. A buffer layer, a second semiconductor film layer, a light-emitting film layer, and a first semiconductor film layer are sequentially grown on the silicon base or sapphire base, and the silicon base or sapphire base is peeled off from the interface between the buffer layer and the silicon base or sapphire base. . For example, the buffer layer is vaporized using a laser lift-off technique to obtain a laminated structure consisting of the second semiconductor film layer, the light emitting film layer, and the first semiconductor film layer. The laminated structure is divided to obtain a plurality of epitaxial layer structures 2, each of which includes a first semiconductor layer 21, a light emitting layer 22, and a second semiconductor layer 23 which are stacked.

In S2, the plurality of epitaxial layer structures 2 are transferred to the base 1, such that each epitaxial layer structure 2 is coupled to one first electrode 12.

In some embodiments, the plurality of epitaxial layer structures 2 are picked-and-placed such that the first semiconductor layer 21 of each epitaxial layer structure 2 is coupled to one first electrode 12. It can be transferred onto the base 1 by a method such as , flip chip or transfer.

As an example, as shown in FIG. 7, a possible implementation of S2 includes the following steps S21-S24.

In S21, a transfer substrate is provided, the second semiconductor layer 23 of each epitaxial layer structure 2 faces away from the transfer substrate, and the arrangement of the plurality of epitaxial layer structures 2 is arranged in a direction opposite to the plurality of first electrodes in the base 1. A plurality of epitaxial layer structures 2 are fixed to the surface of the transfer substrate so as to match the arrangement of 12.

As an example, the plurality of epitaxial layer structures 2 are adhered to the surface of the transfer substrate by an adhesive medium such as an adhesive. The adhesive medium can lose its adhesive properties with subsequent laser irradiation, thereby separating the transfer substrate from the multiple epitaxial layer structure 2 .

In S22, the transfer substrate is placed face down on the base 1, and the plurality of epitaxial layer structures 2 are aligned one-on-one with the plurality of first electrodes 12, so that the first semiconductor layer 21 of each epitaxial layer structure 2 is aligned with one first semiconductor layer 21 of each epitaxial layer structure 2. 1 electrode 12.

In S23, the first semiconductor layer 21 of each epitaxial layer structure 2 is bonded to one first electrode 12 by a bonding process to bond the first semiconductor layer 21 to the first electrode 12 .

In S24, the transfer substrate is removed.

In S3, the plurality of epitaxial layer structures 2 are formed such that the photoresist film covers the surface of the plurality of epitaxial layer structures 2 on the side away from the base 1 and fills the gaps between the plurality of epitaxial layer structures 2. A photoresist film is formed on the side of the layer structure 2 remote from the base 1.

In some embodiments, as shown in FIG. 8, S3 includes the following steps S31-S32.

In S31, the plurality of epitaxial layer structures 2 are coated such that the photoresist covers the surface of the plurality of epitaxial layer structures 2 facing away from the base 1 and fills the gaps between the plurality of epitaxial layer structures 2. Spin coat the photoresist on the side away from the base 1.

For example, an epoxy photoresist is used as the above photoresist. By controlling the spin coating speed according to the predetermined thickness of the passivation layer 3, the photoresist is coated on the surface of the plurality of epitaxial layer structures 2 on the side away from the base 1, and the plurality of epitaxial layers are coated with the photoresist. The gaps between the layered structures 2 are filled. If the thickness of the portion of the photoresist on the multiple epitaxial layer structure 2 is 1 μm, and the thickness of the epitaxial layer structure 2 is 2 μm, the thickness of the portion of the photoresist located in the gap is 3 μm. .

In S32, the photoresist is precured to form a photoresist film.

The substrate spin-coated with photoresist is placed on a high temperature heating stage for several minutes to pre-cure the photoresist and form a photoresist film.

In S4, the photoresist film is patterned to form a plurality of via holes 3v in the photoresist film to obtain the passivation layer 3.

In some embodiments, as shown in FIG. 9, S4 includes the following steps S41-S43.

In S41, a mask is provided on the side of the photoresist film remote from the base 1.

In S42, exposure and development processes are performed on the photoresist film to form a plurality of via holes 3v in the photoresist film.

As an example, a photoresist film is exposed under the shielding effect of a mask. When the photoresist is an epoxy type photoresist, since the epoxy type photoresist is a negative type photoresist, the pattern of the mask is opposite to the pattern of the passivation layer 3 to be formed, and the position corresponding to the via hole 3v of the photoresist film is Expose the other parts. After the exposure is completed, the photoresist film is developed with a developer to dissolve portions of the photoresist film at positions corresponding to the via holes 3v in the developer, thereby forming a plurality of via holes 3v in the photoresist film.

In S43, the photoresist film in which the plurality of via holes 3v are formed is hardened to obtain the passivation layer 3.

The substrate on which the plurality of via holes 3v are formed is placed on a high temperature heating stage to harden the photoresist, thereby obtaining the passivation layer 3.

In S5, residue removal processing is performed on the plurality of via holes 3v by a plasma process, and the photoresist film remaining in the plurality of via holes 3v after the photoresist film is developed is removed.

As an example, the plurality of via holes 3v are treated in a short time by an oxygen plasma treatment process or the like, and after the photoresist film is developed, the photoresist film remaining in the plurality of via holes 3v is removed. In this way, when manufacturing a plurality of second electrodes 4 subsequently, the second electrodes 4 can be brought into direct contact with the second semiconductor layer 23 of the epitaxial layer structure 2, and the second electrodes 4 and the second semiconductor layer 23 can be brought into direct contact with each other. The ohmic contact between the two is better, which is advantageous for transporting carriers.

In S6, a plurality of second electrodes 4 are formed on the side of the passivation layer 3 remote from the base 1, and each of the second electrodes 4 is coupled to one epitaxial layer structure 2 through at least one via hole 3v.

As an example, a plurality of second electrodes 4 are formed on the side of the passivation layer 3 remote from the base 1 by an electrochemical deposition process or a vapor deposition process, and each of the second electrodes 4 forms one epitaxial layer through at least one via hole 3v. It is coupled to the second semiconductor layer 23 of structure 2 .

Some embodiments of the present disclosure provide a method of manufacturing an inorganic light emitting diode substrate 01. In this manufacturing method, the material of the passivation layer 3 is photoresist. During the manufacturing process of the passivation layer 3, the photoresist can fill the gaps between the adjacent epitaxial layer structures 2 during the photoresist application process due to its fluidity, which allows the photoresist to fill the gaps between adjacent epitaxial layer structures 2. The passivation layer 3 can cover the surface of the plurality of epitaxial layer structures 2 on the side remote from the base 1 and can fill the gaps between the plurality of epitaxial layer structures 2, and can cover the surface of the plurality of epitaxial layer structures 2 on the side remote from the base 1. The surface is relatively flat. In this way, it is possible to avoid the problem that the passivation layer 3 is easily cracked at the corner of the epitaxial layer structure on the side away from the base 1, and the problem of leakage caused by cracks in the passivation layer 3 is solved. Further, since the photoresist is an organic material and has better adhesion than inorganic materials such as silicon dioxide, the problem of peeling of the passivation layer 3 does not occur.

Forming a plurality of via holes 3v in a photoresist film through an exposure and development process to obtain a passivation layer 3 is a relatively simple process procedure and relatively low cost. Moreover, there is no need to use the highly difficult deposition process and etching process of the conventional techniques, and the use of expensive deposition equipment and etching equipment is avoided. As a result, the manufacturing process can be simplified and manufacturing costs can be saved.

In the finally obtained inorganic light emitting diode substrate 01, photoresist is used as the material for the passivation layer 3. Compared to the case where silicon dioxide is used as the material of the passivation layer 3, more of the light emitted from the epitaxial layer structure 2 can pass through the passivation layer 3 and be emitted. This is advantageous for improving the light extraction efficiency of the epitaxial layer structure 2, and is further advantageous for improving the light emitting efficiency of the inorganic light emitting diode substrate 01.

As shown in FIG. 10, some embodiments of the present disclosure further provide an inorganic light emitting diode display device 02. The inorganic light emitting diode display device 02 includes an inorganic light emitting diode substrate 01 and a sealing substrate 5 provided on the side of the inorganic light emitting diode substrate 01 on which the second electrode 4 is arranged.

As some examples, the inorganic light-emitting diode display device 02 is a Micro LED (Micro Light-Emitting Diode) display device or a Mini LED (Mini Light-Emitting Diode) display device.

The inorganic light emitting diode display device 02 according to the embodiment of the present disclosure has advantages such as high resolution, energy saving, high brightness, high sharpness, high chroma, relatively fast response speed, and long life. They have the same technical effects, such as higher light extraction efficiency and significantly reduced probability of electrical leakage. A detailed explanation will not be repeated here.

Inorganic light emitting diode display devices according to some embodiments of the present disclosure are applicable to any device that displays images, whether moving (e.g., moving images) or static (e.g., still images), and whether text or images. It can be. More specifically, it is anticipated that the embodiments may be implemented in or in connection with a variety of electronic devices. The various electronic devices include, for example, mobile phones, wireless devices, personal digital assistants (PDAs), handheld or portable computers, GPS receivers/navigation, cameras, MP4 video players, video cameras, game consoles, watches, clocks, calculators. , television monitors, flat panel displays, computer monitors, in-vehicle displays (e.g. trip displays, etc.), navigation units, cockpit controllers and/or displays, camera view displays (e.g. vehicle back camera displays), electronic photography, electronic bulletin boards. or may include, but are not limited to, signage, projectors, building structures, packaging, and aesthetic structures (eg, jewelry image displays).

The above descriptions are only specific embodiments of the present disclosure, and the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make any changes or substitutions within the technical scope of the present disclosure. Therefore, the protection scope of the present disclosure should be determined by the protection scope of the claims.

Claims (11)

a base including a base substrate and a plurality of first electrodes provided on the base substrate ;
a plurality of epitaxial layer structures provided on the base, the plurality of epitaxial layer structures being spaced apart and each first electrode being coupled to one epitaxial layer structure; structure and
A passivation layer made of photoresist, covering the surface of the plurality of epitaxial layer structures on the side remote from the base, filling gaps between the plurality of epitaxial layer structures, and having a plurality of via holes. layer and
a plurality of second electrodes provided on a side of the passivation layer remote from the base, each of which is coupled to an epitaxial layer structure through at least one via hole;
An inorganic light emitting diode substrate comprising: The passivation layer has a first portion that covers a surface of the plurality of epitaxial layer structures remote from the base, and a second portion that fills a gap between the plurality of epitaxial layer structures,
With respect to a surface of the base on which a first electrode is provided , a surface of the first portion remote from the base is flush with or substantially flush with a surface of the second portion remote from the base;
The inorganic light emitting diode substrate according to claim 1. The ratio range between the thickness of the first part of the passivation layer and the thickness of the epitaxial layer structure is from 1:1 to 3:1.
The inorganic light emitting diode substrate according to claim 2. The passivation layer is made of epoxy photoresist.
The inorganic light emitting diode substrate according to any one of claims 1 to 3. Each of the epitaxial layer structures includes a first semiconductor layer, a second semiconductor layer, and a light emitting layer located between the first semiconductor layer and the second semiconductor layer, which are provided in a stacked manner,
Here, in the epitaxial layer structure, the first semiconductor layer is closer to the base than the light emitting layer and the second semiconductor layer,
each of the first electrodes is coupled to a first semiconductor layer within an epitaxial layer structure;
each of the second electrodes is coupled to a second semiconductor layer within an epitaxial layer structure through at least one via hole;
The inorganic light emitting diode substrate according to any one of claims 1 to 4. The base is
the base substrate;
a drive circuit provided on the base substrate;
a first electrode provided on a side of the drive circuit remote from the base substrate and coupled to the drive circuit;
The inorganic light emitting diode substrate according to any one of claims 1 to 5, comprising: providing a base and a plurality of epitaxial layer structures including a plurality of first electrodes;
transferring the plurality of epitaxial layer structures to the base such that each epitaxial layer structure is coupled to one first electrode;
spaced apart from the base of the plurality of epitaxial layer structures such that a photoresist film covers a surface of the plurality of epitaxial layer structures remote from the base and fills gaps between the plurality of epitaxial layer structures. forming the photoresist film on the opposite side;
patterning the photoresist film to form a plurality of via holes in the photoresist film to obtain a passivation layer;
forming a plurality of second electrodes on a side of the passivation layer remote from the base and coupling each second electrode to an epitaxial layer structure through at least one via hole;
A method for manufacturing an inorganic light emitting diode substrate, comprising: Patterning the photoresist film as described above to form a plurality of via holes in the photoresist film to obtain a passivation layer,
providing a mask on a side of the photoresist film remote from the base;
performing an exposure and development process on the photoresist film to form a plurality of via holes in the photoresist film;
Curing the photoresist film in which a plurality of via holes are formed to obtain a passivation layer;
The method for manufacturing an inorganic light emitting diode substrate according to claim 7, comprising: Forming the photoresist film on the side remote from the base of the plurality of epitaxial layer structures described above,
away from the base of the plurality of epitaxial layer structures such that the photoresist covers a surface of the plurality of epitaxial layer structures remote from the base and fills gaps between the plurality of epitaxial layer structures. spin-coating a photoresist on the opposite side;
Precuring the photoresist to form the photoresist film;
The method for manufacturing an inorganic light emitting diode substrate according to claim 7 or 8, comprising: Before forming the plurality of first electrodes on a side of the passivation layer remote from the base,
performing a residue removal process on the plurality of via holes by a plasma process, thereby removing the photoresist film remaining in the plurality of via holes after developing the photoresist film;
The method for manufacturing an inorganic light emitting diode substrate according to any one of claims 7 to 9, further comprising: An inorganic light emitting diode substrate according to any one of claims 1 to 6,
a sealing substrate provided on one side of the inorganic light emitting diode substrate;
An inorganic light emitting diode display device comprising:

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