Light-emitting element and light-emitting device

Abstract

This invention relates to the field of semiconductor manufacturing technology, and particularly to a light-emitting element and device, comprising a first LED sub-unit, a second LED sub-unit, and a first, second, and third pad electrodes. The first pad electrode is electrically connected to both the first and second LED sub-units, the second pad electrode is electrically connected to the first LED sub-unit, and the third pad electrode is electrically connected to the second LED sub-unit. The second LED sub-unit is arranged around the first LED sub-unit, and the light-emitting areas of the second and first LED sub-units are rotationally symmetrical and have overlapping centers of rotation. By arranging the light-emitting areas of each LED sub-unit in a rotationally symmetrical manner, the light-emitting elements can form a correct display orientation when arranged in multiple directions. This solves the problem of the huge workload required for uniformly aligning small-sized light-emitting elements during soldering, and improves the soldering efficiency of light-emitting elements.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a light-emitting element and a light-emitting device. Background Technology

[0002] In recent years, new display technologies have developed rapidly, with OLED and MicroLED technologies receiving extensive research and attention. These new displays offer advantages such as energy efficiency, high resolution, and wide color gamut, leading almost all terminal manufacturers to invest significant human and financial resources in their development. Among these technologies, MicroLED display technology has garnered the most attention and is considered the most likely next-generation display technology. Compared to OLED, another popular technology, it boasts lower power consumption, higher reliability, and faster response time.

[0003] Higher resolution requires smaller pixel pitch, thus necessitating smaller light-emitting elements. These tiny elements need to be soldered individually onto a PCB board. Furthermore, to avoid screen flickering issues, millions of these elements require pre-mixing (similar to stirring a large amount of sand until homogeneous) before soldering. However, ensuring that all these massive and minute elements are aligned in the same direction after mixing—that is, ensuring that the red, blue, and green chips on each element are evenly distributed—becomes extremely difficult. If an incorrectly oriented element is soldered onto the PCB, the mismatch between the element's pins and the PCB's pins will cause display errors or prevent the element from lighting up, affecting product yield. However, aligning such a massive number of tiny MicroLED elements in the same direction using current technology would be prohibitively expensive.

[0004] In summary, improving the welding efficiency of micro-light-emitting elements has become a major problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a light-emitting element, comprising:

[0006] First LED subunit

[0007] The second LED sub-unit, and

[0008] The system comprises a first pad electrode, a second pad electrode, and a third pad electrode. The first pad electrode is electrically connected to both the first LED subunit and the second LED subunit. The second pad electrode is electrically connected to the first LED subunit. The third pad electrode is electrically connected to the second LED subunit.

[0009] The second LED sub-unit is arranged around the first LED sub-unit, and the light-emitting areas of the second LED sub-unit and the first LED sub-unit are rotationally symmetrical and have overlapping rotation centers.

[0010] In some embodiments, a third LED sub-unit is further included, the third LED sub-unit being disposed around the second LED sub-unit, the light-emitting layer of the third LED sub-unit having a rotationally symmetrical pattern and having a rotation center overlapping with that of the second LED sub-unit, and the first pad electrode being electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit.

[0011] It also includes a fourth pad electrode, which is electrically connected to the third LED subunit.

[0012] In some embodiments, the first LED subunit includes a first semiconductor layer, a first light-emitting layer and a second semiconductor layer stacked sequentially.

[0013] The second LED sub-unit includes a third semiconductor layer, a second light-emitting layer, and a fourth semiconductor layer stacked sequentially;

[0014] The third LED subunit includes a fifth semiconductor layer, a third light-emitting layer and a sixth semiconductor layer stacked in sequence;

[0015] The first semiconductor layer, the third semiconductor layer, and the fifth semiconductor layer are all semiconductors of the first conductivity type, and the second semiconductor layer, the fourth semiconductor layer, and the sixth semiconductor layer are all semiconductors of the second conductivity type.

[0016] In some embodiments, the sides of the first semiconductor layer, the third semiconductor layer, and the fifth semiconductor layer that are away from the light-emitting layer are located in the same plane.

[0017] In some embodiments, the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer may each emit light with the same peak wavelength or light with different peak wavelengths.

[0018] In some embodiments, a light-emitting stacked structure is included;

[0019] The light-emitting stacked structure includes a first conductivity type semiconductor layer, a light-emitting layer, and a second conductivity type semiconductor layer stacked sequentially. The light-emitting stacked structure has a first trench and a second trench from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer.

[0020] The light-emitting stack structure is divided into the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit by the first trench and the second trench.

[0021] In some embodiments, the first trench is located between the first LED sub-unit and the second LED sub-unit, and the second trench is located between the second LED sub-unit and the third LED sub-unit.

[0022] In some embodiments, the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer are a first conductivity type semiconductor layer with an integral structure;

[0023] The second conductivity type semiconductor layer is divided into the second semiconductor layer, the fourth semiconductor layer and the sixth semiconductor layer by the first trench and the second trench;

[0024] The light-emitting layer is divided into a first light-emitting layer, a second light-emitting layer, and a third light-emitting layer by the first trench and the second trench.

[0025] In some embodiments, the light-emitting stack structure further has a common trench from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer, and the first pad electrode is electrically connected to the first conductivity type semiconductor layer through the common trench.

[0026] In some embodiments, the common trench is located at the center of the first LED sub-unit.

[0027] In some embodiments, an insulating layer is further included, the insulating layer covering the first trench, the second trench, the side of the light-emitting stack structure opposite to the first conductivity type semiconductor layer, the gap between the common trench and the first pad electrode, and the outer wall of the light-emitting stack structure.

[0028] In some embodiments, the second pad electrode is electrically connected to the second semiconductor layer, the third pad electrode is electrically connected to the fourth semiconductor layer, and the fourth pad electrode is electrically connected to the sixth semiconductor layer.

[0029] In some embodiments, the first pad electrode has a first soldering area exposed to the insulating layer, the second pad electrode has a second soldering area exposed to the insulating layer, the third pad electrode has a third soldering area exposed to the insulating layer, and the fourth pad electrode has a fourth soldering area exposed to the insulating layer.

[0030] In some embodiments, the first welding area, the second welding area, the third welding area, and the fourth welding area are each rotationally symmetric and have overlapping centers of rotation.

[0031] In some embodiments, the graphic formed by the first welding area, the second welding area, the third welding area, and the fourth welding area is a rotationally symmetric graphic.

[0032] In some embodiments, a first wavelength conversion layer and a second wavelength conversion layer are provided on a first surface of the first conductivity type semiconductor layer away from the light-emitting layer, and the first wavelength conversion layer and the second wavelength conversion layer overlap with the orthographic projection of two of the first light-emitting layer, the second light-emitting layer and the third light-emitting layer on the first surface.

[0033] In some embodiments, a barrier layer is provided in the gap between the first wavelength conversion layer and the second wavelength conversion layer.

[0034] In some embodiments, the rotation angle of the rotationally symmetric figure includes 90 degrees or 180 degrees.

[0035] The present invention also provides a light-emitting device, comprising a light-emitting element as described in any of the preceding claims.

[0036] An embodiment of the present invention provides a light-emitting element, which, by symmetrically arranging the light-emitting areas of each LED sub-unit, enables the light-emitting element to form a correct display arrangement direction when arranged in multiple directions. This solves the problem of the huge workload required to unify the arrangement direction when welding small-sized light-emitting elements, and is beneficial to improving the welding efficiency of light-emitting elements.

[0037] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a top view schematic diagram of a light-emitting element according to an exemplary embodiment of the present invention;

[0040] Figure 2 yes Figure 1 A schematic diagram of the cross-section along the middle edge BB';

[0041] Figure 3 This is a schematic diagram of the electrode surface of a light-emitting element according to an exemplary embodiment. Figure 1 ;

[0042] Figure 4 This is a schematic diagram of a circuit board electrode design for a light-emitting element application according to an exemplary embodiment;

[0043] Figure 5 This is a schematic diagram of the electrode surface of a light-emitting element according to an exemplary embodiment. Figure 2 ;

[0044] Figure 6 and Figure 7 This is a schematic cross-sectional view of the manufacturing process of a light-emitting element according to an exemplary embodiment.

[0045] Figure label:

[0046] 2-Light-emitting element; 10-First LED sub-unit; 20-Second LED sub-unit; 30-Third LED sub-unit; 11-First semiconductor layer; 12-First light-emitting layer; 13-Second semiconductor layer; 21-Third semiconductor layer; 22-Second light-emitting layer; 23-Fourth semiconductor layer; 31-Fifth semiconductor layer; 32-Third light-emitting layer; 33-Sixth semiconductor layer; 41-First pad electrode; 42-Second pad electrode; 43-Third pad electrode; 44-Fourth pad electrode; 41a-First welding area; 42a-Second welding area; 43a-Third welding area; 44a-Fourth welding area; 60-Insulating layer; 71-First wavelength conversion layer; 72-Second wavelength conversion layer; 73-Barrier layer; 81-First trench; 82-Second trench; 83-Common trench; S1-First surface; S2-Second surface; 91-First conductivity type semiconductor layer; 92-Light-emitting layer; 93-Second conductivity type semiconductor layer. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings; the technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] In the following, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As used herein, the light-emitting element or LED subunit according to the exemplary embodiments may include a micro light-emitting element having a surface area of ​​less than about 10,000 square μm, as known in the art. In other exemplary embodiments, depending on the specific application, the micro light-emitting element may have a surface area of ​​less than about 4,000 square μm or less than about 2,500 square μm. However, the present invention does not particularly limit the applicable size of the light-emitting element.

[0049] To achieve at least one or more of the aforementioned advantages, please refer to Figure 1 and Figure 2 , Figure 1 This is a top view schematic diagram of the light-emitting element 2 according to an exemplary embodiment; Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the light-emitting element 2 along BB'.

[0050] Reference Figure 1 and Figure 2 The light-emitting element 2 includes a light-emitting stack structure having a first LED sub-unit 10, a second LED sub-unit 20, and a third LED sub-unit 30 arranged horizontally, and a first pad electrode 41, a second pad electrode 42, a third pad electrode 43, and a fourth pad electrode 44 electrically connected to the LED sub-units 10, 20, and 30. The light-emitting element 2 also includes an insulating layer 60 surrounding and covering one side of the light-emitting stack structure and each electrode. The side of the light-emitting stack structure facing away from the insulating layer 60 is defined as a first surface S1, and a second surface S2 is formed on the side of the insulating layer 60 facing away from the light-emitting stack structure. In the following description, the placement orientation of the illustrated embodiment will be used, that is, the first surface S1 is located on the upper side or top surface of the light-emitting stack structure, and the second surface S2 is located on the lower side or bottom surface of the light-emitting element 2. Each electrode is electrically connected to the light-emitting stack structure internally and extends to form a soldering area exposed on the second surface S2.

[0051] Among them, although attached Figure 1 and Figure 2 A light-emitting stack structure comprising three LED sub-units 10, 20, and 30 is shown, but the inventive concept is not limited to a specific number of LED sub-units formed in the light-emitting stack structure. For example, in some exemplary embodiments, the light-emitting stack structure may include two or more LED sub-units. Hereinafter, the light-emitting element 2 will be described with reference to the light-emitting stack structure comprising three LED sub-units 10, 20, and 30 according to exemplary embodiments.

[0052] In some embodiments, the light-emitting stack structure can be formed on a substrate (not shown), which may include a light-transmitting insulating material to allow light to pass through. For example, it may be made of materials such as sapphire (Al2O3), GaN, SiC, or glass, but the concept of the present invention is not limited thereto. In this embodiment, the light-emitting element 2 is described in detail in the state where the light-emitting stack structure is detached from the substrate.

[0053] Each of the first LED subunit 10, the second LED subunit 20, and the third LED subunit 30 is configured to emit light toward the first surface S1. In some embodiments, each of the first LED subunit 10, the second LED subunit 20, and the third LED subunit 30 may be made of different semiconductor materials, such that the light-emitting layer of each of the first LED subunit 10, the second LED subunit 20, and the third LED subunit 30 can emit light with different peak wavelengths. For example, the first LED subunit 10, the second LED subunit 20, and the third LED subunit 30 may emit blue light, green light, and red light, respectively. However, the inventive concept is not limited thereto. As another example, the first LED subunit 10, the second LED subunit 20, and the third LED subunit 30 may emit red light, green light, and blue light, respectively.

[0054] The first LED sub-unit 10 includes a first semiconductor layer 11, a first light-emitting layer 12, and a second semiconductor layer 13 stacked sequentially. In some embodiments, the first light-emitting layer 12 may include a semiconductor material that emits blue light, such as gallium nitride (GaN), indium gallium nitride (InGaN), and zinc selenide (ZnSe), but is not limited thereto.

[0055] The second LED subunit 20 includes a third semiconductor layer 21, a second light-emitting layer 22, and a fourth semiconductor layer 23 stacked sequentially. In some embodiments, the second light-emitting layer 22 may include a semiconductor material that emits green light, such as indium gallium nitride (InGaN), gallium nitride (GaN), gallium phosphide (GaP), aluminum gallium indium phosphide (AlGaInP), and aluminum gallium phosphide (AlGaP), but is not limited thereto.

[0056] The third LED subunit 30 includes a fifth semiconductor layer 31, a third light-emitting layer 32, and a sixth semiconductor layer 33 stacked sequentially. In some embodiments, the third light-emitting layer 32 may include a semiconductor material that emits red light, such as, but is not limited to, aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), and gallium phosphide (GaP).

[0057] The first semiconductor layer 11, the third semiconductor layer 21, and the fifth semiconductor layer 31 are all first conductivity type semiconductors; the second semiconductor layer 12, the fourth semiconductor layer 22, and the sixth semiconductor layer 32 are all second conductivity type semiconductors. Hereinafter, the first semiconductor layer 11, the third semiconductor layer 21, or the fifth semiconductor layer 31 are simply referred to as first conductivity type semiconductors, the first light-emitting layer 12, the second light-emitting layer 22, or the third light-emitting layer 32 are simply referred to as light-emitting layers, and the second semiconductor layer 12, the fourth semiconductor layer 22, or the sixth semiconductor layer 32 are simply referred to as second conductivity type semiconductors. According to an exemplary embodiment, the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 of the light-emitting element 2 are arranged horizontally, that is, the side of the first semiconductor layer 11, the third semiconductor layer 21, and the fifth semiconductor layer 31 that faces away from the light-emitting layer is located in the same plane (first surface S1).

[0058] The first conductivity type semiconductor can be an N-type semiconductor, which can provide electrons to the light-emitting layer under the influence of a power source. In some embodiments, the first conductivity type semiconductor includes an N-type doped nitride layer, a phosphide layer, or an arsenide layer. The N-type doped nitride layer, phosphide, or arsenide may include one or more N-type impurities of group IV elements. The N-type impurities may include one or a combination of Si, Ge, and Sn.

[0059] The light-emitting layer is formed on a semiconductor of a first conductivity type, and can be a quantum well (QW) structure. In some embodiments, the light-emitting layer can also be a multiple quantum well (MQW) structure, wherein the multiple quantum well structure includes multiple quantum well layers (Wells) and multiple quantum barrier layers arranged alternately in a repeating manner, such as GaN / AlGaN, InAlGaN / InAlGaN, InGaN / AlGaN, GaInP / AlGaInP, GaInP / AlInP, InGaAS / AlInGaAS multiple quantum well structures. Furthermore, the composition and thickness of the well layers within the light-emitting layer determine the wavelength of the generated light. To improve the luminous efficiency of the light-emitting layer, this can be achieved by changing the depth of the quantum wells, the number of paired quantum wells and quantum barriers, their thickness, and / or other characteristics within the light-emitting layer.

[0060] The second conductivity type semiconductor layer is a P-type semiconductor layer, which can provide holes to the light-emitting layer under power. In some embodiments, the second conductivity type semiconductor layer includes a P-type doped nitride layer, a phosphide layer, or an arsenide layer. The P-type doped nitride layer, phosphide layer, or arsenide layer may include one or more P-type impurities of group II elements. The P-type impurities may include one or a combination of Mg, Zn, and Be. The second conductivity type semiconductor layer can be a single-layer structure or a multi-layer structure with different compositions. Furthermore, the arrangement of LED sub-units 10, 20, or 30 is not limited to this, and other types of LED sub-unit structures can be selected according to actual needs.

[0061] In some embodiments, one or more LED sub-units in the light-emitting stack structure may be made of the same semiconductor material, so that the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 can emit light with substantially the same peak wavelength. For example, in some embodiments, the light-emitting layers of each of the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 may all include a blue-light-emitting semiconductor material, such as gallium nitride (GaN), indium gallium nitride (InGaN), and zinc selenide (ZnSe), but are not limited thereto. Further, in order for this exemplary embodiment to emit full-color light, in some embodiments, such as... Figure 1 and Figure 2 As shown, the light-emitting element 2 further includes a wavelength conversion layer disposed on the first surface S1, comprising a first wavelength conversion layer 710 and a second wavelength conversion layer 72. The first wavelength conversion layer 71 and the second wavelength conversion layer 72 overlap with the orthographic projection of the light-emitting layer of two of the first LED sub-units 10, 20, and 30 onto the first surface S1. The wavelength conversion layer is used to absorb light emitted from the light-emitting layer and stimulate the emission of light with a peak wavelength different from that emitted by the light-emitting layer. In other words, the color of the light emitted by the light-emitting layer changes after passing through the wavelength conversion layer.

[0062] In some embodiments, the wavelength conversion layer can be one or any combination of phosphors, fluorescent adhesives, or fluorescent ceramics. In another embodiment, the wavelength conversion layer can be a quantum dot material. Quantum dots, also known as nanocrystals, are nanoparticles composed of group II-VI or III-V elements. The particle size of quantum dots is generally between 1-10 nm, making them suitable for smaller micro-display devices. Quantum dots also exhibit electroluminescence and photoluminescence effects. When stimulated, quantum dots can emit fluorescence, and the color of the emission is determined by the material and size. Therefore, the wavelength of the emitted light can be changed by controlling the particle size of the quantum dots. The smaller the quantum dot particle size, the more blue the emitted color. The larger the quantum dot particle size, the more red the emitted color. Various chemical components can be used to fabricate quantum dots. The emission color of quantum dots can cover the entire visible region from blue to red light. Quantum dots have high light absorption and emission efficiency, a narrow half-width at half-maximum (HWHM), and a wide absorption spectrum, thus possessing high color purity and saturation. Quantum dots have the advantages of simple structure, thinness, and rollability, making them very suitable for applications in the field of micro-displays.

[0063] In some embodiments, the wavelength conversion layer may further include a third wavelength conversion layer, so that the blue light emitted by the first LED subunit 10, the second LED subunit 20 and the third LED subunit respectively emits three different colors of light after passing through the wavelength conversion layer, so as to achieve full-color display.

[0064] In the following detailed description, the structure of the light-emitting element 2 in the illustrated embodiment will be used as an example. Its first wavelength conversion layer 71 is disposed above the second LED sub-unit 20. After absorbing the blue light emitted by the second LED sub-unit 20, the first wavelength conversion layer 71 can emit red light, for example. The second wavelength conversion layer 73 is disposed above the third LED sub-unit 30. After absorbing the blue light emitted by the third LED sub-unit 30, the second wavelength conversion layer 72 can emit green light, for example. A transparent material is disposed above the first LED sub-unit 10 so that the blue light emitted by the first LED sub-unit 10 can be transmitted. The first LED sub-unit 10, together with the first wavelength conversion layer 71 and the second wavelength conversion layer 72, achieves RGB full-color display.

[0065] According to the illustrated embodiment, each of the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 can be driven independently. More specifically, one of the first conductivity type semiconductor and the second conductivity type semiconductor in each LED sub-unit can be applied with a common voltage, and the other of the first conductivity type semiconductor and the second conductivity type semiconductor in each LED sub-unit can be applied with a corresponding light-emitting signal. For example, according to the illustrated exemplary embodiment, the first conductivity type semiconductor of each LED sub-unit can be n-type, and the second conductivity type semiconductor of each LED sub-unit can be p-type. Hereinafter, according to the illustrated exemplary embodiment, the first conductivity type semiconductor and the second conductivity type semiconductor can be interchangeably referred to as a p-type semiconductor layer and an n-type semiconductor layer, respectively.

[0066] Furthermore, a common voltage is applied to the n-type semiconductor layer of each LED sub-unit through the first pad electrode 41, and corresponding light-emitting signals are applied to the p-type semiconductor layers of the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 through the second pad electrode 42, the third pad electrode 43, and the fourth pad electrode 44, respectively. The first pad electrode 41 is electrically connected to the n-type semiconductor layers of the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30, namely the first semiconductor layer 11, the third semiconductor layer 21, and the fifth semiconductor layer 31, respectively. The second pad electrode 42 is electrically connected to the p-type semiconductor layer of the first LED sub-unit 10, namely the second semiconductor layer 12. The third pad electrode 43 is electrically connected to the p-type semiconductor layer of the second LED sub-unit 20, namely the fourth semiconductor layer 22. The fourth pad electrode 44 is electrically connected to the p-type semiconductor layer of the third LED sub-unit 30, namely the sixth semiconductor layer 32. The first pad electrode 41, the second pad electrode 42, the third pad electrode 43, and the fourth pad electrode 44 are respectively connected to the first welding region 41a, the second welding region 42a, the third welding region 43a, and the fourth welding region 44a exposed on the second surface S2. This structure enables each of the LED sub-units 10, 20, and 30 to be driven individually, while having an n-type common-electrode light-emitting stack structure.

[0067] Although the light-emitting element 2 according to the illustrated embodiment is an n-type common-electrode light-emitting stack structure, the concept of the present invention is not limited thereto. For example, in some embodiments, the first conductivity type semiconductor of each LED sub-unit can be a p-type semiconductor layer, and the second conductivity type semiconductor can be an n-type semiconductor layer, to form a light-emitting stack structure with a p-type common electrode. The light-emitting element 2 will be described exemplarily below with reference to the illustrated n-type common-electrode light-emitting stack structure.

[0068] According to an exemplary embodiment, such as Figure 2As shown, the light-emitting stacked structure has a first conductive type semiconductor layer, a light-emitting layer, and a second conductive type semiconductor layer stacked sequentially. The side of the first conductive type semiconductor layer facing away from the light-emitting layer is a first surface S1. The light-emitting stacked structure also has a first trench 81 and a second trench 82 extending from the second conductive type semiconductor layer to the first conductive type semiconductor layer. The first trench 81 and the second trench 82 divide the light-emitting stacked structure into three regions, namely a first LED sub-unit 10, a second LED sub-unit 20, and a third LED sub-unit 30. The first trench 81 is located between the first LED sub-unit 10 and the second LED sub-unit 20, and the second trench 82 is located between the second LED sub-unit 20 and the third LED sub-unit 30.

[0069] In some embodiments, the first trench 81 and the second trench 82 extend from the side of the second conductive type semiconductor layer away from the light-emitting layer into the light-emitting stack structure and penetrate the light-emitting layer to the side of the first conductive type semiconductor layer adjacent to the light-emitting layer, or continue to extend into the interior of the first conductive type semiconductor layer. Thus, the second conductive type semiconductor layer is divided into three regions by the first trench 81 and the second trench 82: the second semiconductor layer 13, the fourth semiconductor layer 23, and the sixth semiconductor layer 33. The light-emitting layer is also divided into three regions by the first trench 81 and the second trench 82: the first light-emitting layer 12, the second light-emitting layer 22, and the third light-emitting layer 32. The first conductive type semiconductor layer is not penetrated by the first trench 81 and the second trench 82, forming a single structure. However, viewed from the normal direction of the first surface S1, the first conductive type semiconductor layer includes the first semiconductor layer 11, the third semiconductor layer 21, and the fifth semiconductor layer 31. The first semiconductor layer 11 overlaps with the orthographic projections of the first light-emitting layer 12 and the second semiconductor layer 13 on the first surface S1, together forming the first LED sub-unit 10; the third semiconductor layer 21 overlaps with the orthographic projections of the second light-emitting layer 22 and the fourth semiconductor layer 23 on the first surface S1, together forming the second LED sub-unit 20; the fifth semiconductor layer 31 overlaps with the orthographic projections of the third light-emitting layer 32 and the sixth semiconductor layer 33 on the first surface S1, together forming the third LED sub-unit 30.

[0070] According to an exemplary embodiment, in the process of forming the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30, a structure of three LED sub-units connected together by etching trenches in the stacked structure of the first conductivity type semiconductor layer, the light-emitting layer, and the second conductivity type semiconductor layer is formed. Each of the three LED sub-units forms a common electrode on one side through the first conductivity type semiconductor layer, and the other side forms a barrier between them to independently supply power. In some embodiments, viewed along the normal direction of the first surface S1, the first trench 81 and the second trench 82 each have a rotationally symmetrical annular pattern. The second trench 82 is located outside the first trench 81, thus forming a structure in which the second LED sub-unit 20 is disposed around the first LED sub-unit 10, and the third LED sub-unit 30 is disposed around the second LED sub-unit 20. The light-emitting areas, i.e., the light-emitting layers, of the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 each have a rotationally symmetrical pattern and an overlapping rotational shape. Thus, when soldering the light-emitting element 2, it is not necessary to consider the issue of the light-emitting layers needing to be aligned in a uniform direction with respect to the light-emitting element 2. For example, even when several light-emitting elements 2 form an array, their individual rotation will not significantly affect the display effect of the array, which is beneficial for simplifying the process. Furthermore, the concept of this invention is not limited to the first light-emitting layer 12, the second light-emitting layer 22, and the third light-emitting layer 32 being rotationally symmetrical. In other words, the design objective of this invention is that each light-emitting layer is located in the center of the light-emitting element 2 and is rotationally symmetrical to eliminate the problem of image display effect that may occur due to the rotation of the light-emitting element 2 itself during soldering. However, it is permissible to disrupt the rotational symmetry to a certain extent during the manufacturing process due to manufacturing tolerances, structural requirements, etc.

[0071] In some embodiments, the light-emitting stack structure further includes a common trench 83 extending from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer, such as... Figure 2 As shown, a common trench 83 is disposed in the center of the first LED sub-unit 10, penetrating the second semiconductor layer 13 and the first light-emitting layer 12, thus exposing the side of the first semiconductor layer 10 facing away from the first surface S1. A first pad electrode 41 is formed in the common trench 83 and electrically connected to the first semiconductor layer 10. Preferably, as shown... Figure 3 As shown, Figure 3 A schematic diagram of the electrode surface of the light-emitting element 2 according to an exemplary embodiment. Figure 1 The first pad electrode 41 is located at the center of the first LED sub-unit 10, and its cross-sectional shape is rotationally symmetrical, such as a square or a circle. The first pad electrode 41 extends from the first semiconductor layer 11 to the second surface S2, exposing the first welding area 41a. In some embodiments, the first pad electrode 41 has an elongated columnar structure, and the first welding area 41a has a rotationally symmetrical shape.

[0072] The second pad electrode 42 is formed on the exposed surface of the second semiconductor layer 13 and is electrically connected to the second semiconductor layer 13. Preferably, in some embodiments, the second pad electrode 42 includes a plurality of second sub-pad electrodes formed on the second semiconductor layer 13, for example, four second sub-pad electrodes in this embodiment. Viewed from the normal direction of the first surface S1, as shown... Figure 3 As shown, the four second sub-pad electrodes are rotationally symmetrically distributed on the second semiconductor layer 13. Each second sub-pad electrode extends from the surface of the second semiconductor layer 13 to the second surface S2, exposing the second welding area 42a. Each second sub-pad electrode has a slender columnar structure. The second welding area 42a has a rotationally symmetrical shape, and its center of symmetry overlaps with that of the first welding area 41a.

[0073] The third pad electrode 43 is formed on the exposed surface of the second semiconductor layer 23 and electrically connected to the fourth semiconductor layer 23. Preferably, in some embodiments, the third pad electrode 43 includes a plurality of third sub-pad electrodes formed on the fourth semiconductor layer 23, for example, four third sub-pad electrodes in this embodiment. Viewed from the normal direction of the first surface S1, as shown... Figure 3 As shown, the four third sub-pad electrodes are rotationally symmetrically distributed on the fourth semiconductor layer 23. Each third sub-pad electrode extends from the surface of the fourth semiconductor layer 23 to the second surface S2, exposing the third welding area 43a. Each third sub-pad electrode has a slender columnar structure. The third welding area 43a has a rotationally symmetrical shape, and its center of symmetry overlaps with the first welding area 41a.

[0074] The fourth pad electrode 44 is formed on the exposed surface of the sixth semiconductor layer 33 and is electrically connected to the sixth semiconductor layer 33. Preferably, in some embodiments, the fourth pad electrode 44 includes a plurality of fourth sub-pad electrodes formed on the sixth semiconductor layer 33, for example, four fourth sub-pad electrodes in this embodiment. Viewed from the normal direction of the first surface S1, as shown... Figure 3 As shown, the four fourth sub-pad electrodes are distributed in a rotationally symmetrical manner on the sixth semiconductor layer 33. Each fourth sub-pad electrode extends from the surface of the sixth semiconductor layer 33 to the second surface S2, exposing the fourth welding region 44a. Each fourth sub-pad electrode has a slender columnar structure. The fourth welding region 44a has a rotationally symmetrical shape, and its center of symmetry overlaps with that of the first welding region 41a.

[0075] It should be understood that, according to the above exemplary embodiments, when the inventive concept is applied to a square light-emitting element 2 to form an array, the light-emitting element 2 needs to be arranged in a rectangular array. Therefore, in order to simplify the welding process of the light-emitting element 2, the rotation angle of the rotationally symmetric figure in the above exemplary embodiments is 90 degrees or 180 degrees, preferably 90 degrees, so that the light-emitting element 2 can be correctly welded and connected in all four directions. When welding hundreds of thousands or millions of light-emitting elements 2, the completed sample can be welded onto a PCB board after random mixing. The electrode design of the PCB board is as follows: Figure 4 As shown, there are four pads C, B, G, and R, corresponding to the first pad electrode 41, the second pad electrode 42, the third pad electrode 43, and the fourth pad electrode 44, respectively. Thus, the light-emitting element 2 only needs to distinguish between its front and back sides, without needing to distinguish its orientation, for soldering. However, the invention is not limited to the application of square light-emitting elements; therefore, the rotation angle of the rotationally symmetric shape can also be adjusted. For example, when the light-emitting element is a hexagonal close-packed array, the rotation angle can be 60 degrees.

[0076] However, the design concept of the electrode welding area of ​​the light-emitting element 2 is not limited to this, such as... Figure 5 As shown, Figure 5 A schematic diagram of the electrode surface of the light-emitting element 2 according to an exemplary embodiment. Figure 2 A connection electrode (not shown) can be disposed in the insulating layer 60. The connection electrode includes a first connection electrode electrically connected to the first semiconductor layer 11, a second connection electrode electrically connected to the second semiconductor layer 13, a third connection electrode electrically connected to the fourth semiconductor layer 23, and a fourth connection electrode electrically connected to the sixth semiconductor layer 33. A first pad electrode 41 is disposed on top of the first connection electrode and partially overlaps and contacts it; a second pad electrode 42 is disposed on top of the second connection electrode and partially overlaps and contacts it; a third pad electrode 43 is disposed on top of the third connection electrode and partially overlaps and contacts it; and a fourth pad electrode 44 is disposed on top of the fourth connection electrode and partially overlaps and contacts it. A planar coordinate system is established with the center point of the light-emitting element 2 as the origin. Figure 5 In the illustrated embodiment, the first pad electrode 41 is located in the first quadrant of the coordinate system, the second pad electrode 42 is located in the second quadrant of the coordinate system, the third pad electrode is located in the third quadrant of the coordinate system, and the fourth pad electrode 44 is located in the fourth quadrant of the coordinate system. Furthermore, the first soldering region 41a, the second soldering region 42a, the third soldering region 43a, and the fourth soldering region 44a exposed on the second surface S2 are arranged as follows: Figure 5The distribution shown makes the pattern formed by the four components rotationally symmetrical. Preferably, in some embodiments, to facilitate the formation of each pad electrode of this distribution structure, the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30 can each be a ring structure including three nested rectangles or circles and a corresponding shape, so that each pad electrode can have an overlapping area with the corresponding LED sub-unit in the normal direction of the first surface S1, so as to facilitate the fabrication of the connection electrode and the pad electrode.

[0077] In some embodiments, the insulating layer 60 covers the side of the light-emitting stack structure where the pad electrodes are located. The insulating layer 60 fills the first trench 81 and the second trench 82 to isolate the electrical connection between the first LED sub-unit 10, the second LED sub-unit 20, and the third LED sub-unit 30, thereby preventing cross-current. Furthermore, the insulating layer 60 has different functions depending on its location. For example, covering the sidewall of the light-emitting stack structure can prevent electrical connection between the first and second conductive semiconductor layers due to conductive material leakage, thereby reducing short-circuit abnormalities in the LED sub-units. The material of the insulating layer 60 includes a non-conductive material. The non-conductive material is preferably an inorganic material or a dielectric material. The inorganic material may include silicone. The dielectric material may include aluminum oxide (AlO), silicon nitride (SiNx), silicon oxide (SiOx), titanium oxide (TiOx), or magnesium fluoride (MgFx), which can be electrically insulating materials. For example, the insulating layer 60 may be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate, or a combination thereof, such as a Bragg mirror (DBR) formed by repeatedly stacking two materials.

[0078] According to an exemplary embodiment, such as Figure 1As shown, the light-emitting element 2 further includes a barrier layer 73 disposed in the gap between the first wavelength conversion layer 71 and the second wavelength conversion layer 72. Preferably, the barrier layer 73 can be a black film layer for absorbing light, specifically preferably a black film layer formed by dispersing black filler components with a particle size of no more than 1 μm in transparent or translucent materials such as silicone, epoxy resin, polyimide, low-temperature glass, polysiloxane, and polysilazane. The black filler components include, but are not limited to, carbon black, titanium nitride, iron oxide, iron oxide, and iron powder. In some embodiments, the particle size range of the black filler components in the barrier layer 73 is preferably 10~100 nm, or 100~200 nm, or 200~300 nm, or 300 nm~500 nm. The black filler components can also be black dyes. This is to reduce the influence of crosstalk, so that the wavelength conversion layer is excited by the light emitted by the LED sub-unit opposite to it as much as possible, improve the independent driving effect of each LED sub-unit of the light-emitting element 2, and increase the accuracy and recognition of the emitted color light. Preferably, in some embodiments, a barrier layer 73 may be provided on the sidewalls of the first trench 81 and the second trench 82 to further improve the blocking effect of colored light. In addition, the barrier layer 73 may also be disposed in the gap between the first wavelength conversion layer 71 and the transparent material above the first LED sub-unit 10.

[0079] Furthermore, when the light-emitting element 2 is mounted onto another substrate to manufacture a display device, for example, due to the stacked structure of the light-emitting chips 100, the number of chips to be mounted can be significantly reduced compared to conventional light-emitting devices. Thus, the manufacturing of a display device using the light-emitting element 1 can be significantly simplified, especially when hundreds of thousands or millions of pixels are formed in a single display device. Therefore, the stacked structure design of the LED sub-units 10, 20, and 30, and the rotational symmetry of the welding areas of each electrode and the light-emitting areas, significantly simplify the subsequent manufacturing and use of the light-emitting element 2.

[0080] In the following description, the accompanying drawings will be used as a reference. Figure 2 and Figure 3 The formation process of the light-emitting element 2 in the exemplary embodiment shown.

[0081] Reference Figure 6 The first conductivity type semiconductor layer 91, the light-emitting layer 92, and the second conductivity type semiconductor layer 93 can be grown by, for example, metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) to form the initial epitaxy of the light-emitting stack structure.

[0082] Reference Figure 7The light-emitting stack structure, consisting of a first conductive semiconductor layer 91, a light-emitting layer 92, and a second conductive semiconductor layer 93, is partially patterned using an etching process, forming a first trench 81, a second trench 82, and a common trench 83. The light-emitting stack structure is divided into a first LED sub-unit 10, a second LED sub-unit 20, and a third LED sub-unit 30 via the first trench 81 and the second trench 82. The first light-emitting layer 12, the second light-emitting layer 22, and the third light-emitting layer 32 are each rotationally symmetrical and have overlapping centers of rotation.

[0083] Return to reference Figure 2 First pad electrodes 41, second pad electrodes 42, third pad electrodes 43, and fourth pad electrodes 44 are formed on the surfaces of the first semiconductor layer 11, the second semiconductor layer 13, the fourth semiconductor layer 23, and the sixth semiconductor layer 33 exposed in the common trench 83, respectively. The first welding region 41a, the second welding region 42a, the third welding region 43a, and the fourth welding region 44a are each rotationally symmetrical and have overlapping centers of rotation. Specifically, a seed layer is deposited as a conductive surface on the light-emitting stack structure, and a photoresist pattern can be formed by exposing the seed layer at the locations where the pad electrodes will be formed. The seed layer can be deposited to a thickness of approximately 1000 angstroms, but is not limited to this. Subsequently, the seed layer can be plated with metals such as Cu, Ni, Ti, Sb, Zn, Mo, Co, Sn, Ag, or alloys of these metals, and any remaining photoresist pattern and seed layer can be removed. In some exemplary embodiments, additional metals can be deposited or plated onto the pad electrodes by electroless nickel immersion gold (ENIG) or similar methods to prevent or at least suppress electrode oxidation.

[0084] Next, an insulating layer 60 is formed on the side of the light-emitting stack structure opposite to the first surface S1. The insulating layer 60 fills the gap between the first trench 81, the second trench 82, and the common trench 83 and the first pad electrode 41, and covers the side surfaces of each pad electrode. The insulating layer 60 can be formed into a second surface S2 substantially flush with the top surfaces of the pad electrodes 41, 42, 43, and 44 by a polishing process or the like. Preferably, the top surfaces of the pad electrodes 41, 42, 43, and 44 can slightly protrude from the second surface S2. According to an exemplary embodiment, the insulating layer 60 may include, but is not limited to, a black epoxy molding compound (EMC). For example, in some exemplary embodiments, the insulating layer 60 may include a photosensitive polyimide (PID) dry film. In this way, the insulating layer 60 can protect the light-emitting structure from external impacts that may be applied during subsequent processes, and provide sufficient contact area to the light-emitting element 2 to facilitate its handling during subsequent transfer steps. In addition, the insulating layer 60 can prevent light from leaking toward the side surface of the light-emitting element 2, so as to prevent or at least suppress interference from the light emitted from the adjacent light-emitting element 2.

[0085] Then, a first wavelength conversion layer 71, a second wavelength conversion layer 72, and a transparent material are formed on the first surface S1, such that the transparent material is located on the first LED sub-unit 10, the first wavelength conversion layer 71 is located on the second LED sub-unit 20, and the second wavelength conversion layer 72 is located on the third LED sub-unit 30. Furthermore, a barrier layer 73 is formed in the gaps between the first wavelength conversion layer 71, the second wavelength conversion layer 72, and the transparent material.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-emitting element, characterized in that, include: First LED subunit The second LED sub-unit, and The system comprises a first pad electrode, a second pad electrode, and a third pad electrode. The first pad electrode is electrically connected to both the first LED subunit and the second LED subunit. The second pad electrode is electrically connected to the first LED subunit. The third pad electrode is electrically connected to the second LED subunit. The second LED sub-unit is arranged around the first LED sub-unit, and the light-emitting areas of the second LED sub-unit and the first LED sub-unit are rotationally symmetrical and have overlapping rotation centers; The first pad electrode, the second pad electrode, and the third pad electrode are each rotationally symmetrical and have a rotation center that overlaps with the light-emitting areas of the first LED sub-unit and the second LED sub-unit, respectively.

2. The light-emitting element according to claim 1, characterized in that: It also includes a third LED sub-unit, which is arranged around the second LED sub-unit. The light-emitting layer of the third LED sub-unit has a rotationally symmetrical shape and has a rotation center that overlaps with that of the second LED sub-unit. The first pad electrode is electrically connected to the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit. It also includes a fourth pad electrode, which is electrically connected to the third LED subunit.

3. The light-emitting element according to claim 2, characterized in that: The first LED sub-unit includes a first semiconductor layer, a first light-emitting layer, and a second semiconductor layer stacked sequentially. The second LED sub-unit includes a third semiconductor layer, a second light-emitting layer, and a fourth semiconductor layer stacked sequentially; The third LED subunit includes a fifth semiconductor layer, a third light-emitting layer and a sixth semiconductor layer stacked in sequence; The first semiconductor layer, the third semiconductor layer, and the fifth semiconductor layer are all semiconductors of the first conductivity type, and the second semiconductor layer, the fourth semiconductor layer, and the sixth semiconductor layer are all semiconductors of the second conductivity type.

4. The light-emitting element according to claim 3, characterized in that: The sides of the first semiconductor layer, the third semiconductor layer, and the fifth semiconductor layer that are away from the light-emitting layer are located in the same plane.

5. The light-emitting element according to claim 3, characterized in that: The first light-emitting layer, the second light-emitting layer, and the third light-emitting layer can each emit light with the same peak wavelength or light with different peak wavelengths.

6. The light-emitting element according to claim 3, characterized in that: Including light-emitting stacked structures; The light-emitting stacked structure includes a first conductivity type semiconductor layer, a light-emitting layer, and a second conductivity type semiconductor layer stacked sequentially. The light-emitting stacked structure has a first trench and a second trench from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer. The light-emitting stack structure is divided into the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit by the first trench and the second trench.

7. The light-emitting element according to claim 6, characterized in that: The first trench is located between the first LED sub-unit and the second LED sub-unit, and the second trench is located between the second LED sub-unit and the third LED sub-unit.

8. The light-emitting element according to claim 6, characterized in that: The first semiconductor layer, the second semiconductor layer, and the third semiconductor layer are a first conductivity type semiconductor layer with an integral structure; The second conductivity type semiconductor layer is divided into the second semiconductor layer, the fourth semiconductor layer and the sixth semiconductor layer by the first trench and the second trench; The light-emitting layer is divided into a first light-emitting layer, a second light-emitting layer, and a third light-emitting layer by the first trench and the second trench.

9. The light-emitting element according to claim 6, characterized in that: The light-emitting stack structure also has a common trench from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer, and the first pad electrode is electrically connected to the first conductivity type semiconductor layer through the common trench.

10. The light-emitting element according to claim 9, characterized in that: The common-electrode trench is located in the center of the first LED sub-unit.

11. The light-emitting element according to claim 10, characterized in that: It also includes an insulating layer that covers the first trench, the second trench, the side of the light-emitting stack structure away from the first conductivity type semiconductor layer, the gap between the common trench and the first pad electrode, and the outer wall of the light-emitting stack structure.

12. The light-emitting element according to claim 3, characterized in that: The second pad electrode is electrically connected to the second semiconductor layer, the third pad electrode is electrically connected to the fourth semiconductor layer, and the fourth pad electrode is electrically connected to the sixth semiconductor layer.

13. The light-emitting element according to claim 11, characterized in that: The first pad electrode has a first soldering area exposed to the insulating layer, the second pad electrode has a second soldering area exposed to the insulating layer, the third pad electrode has a third soldering area exposed to the insulating layer, and the fourth pad electrode has a fourth soldering area exposed to the insulating layer.

14. The light-emitting element according to claim 13, characterized in that: The first welding area, the second welding area, the third welding area, and the fourth welding area are each rotationally symmetrical and have overlapping centers of rotation.

15. The light-emitting element according to claim 13, characterized in that: The figure formed by the first welding area, the second welding area, the third welding area, and the fourth welding area is rotationally symmetric.

16. The light-emitting element according to claim 6, characterized in that: A first wavelength conversion layer and a second wavelength conversion layer are provided on a first surface of the first conductivity type semiconductor layer away from the light-emitting layer. The first wavelength conversion layer and the second wavelength conversion layer overlap with the orthographic projection of two of the first light-emitting layer, the second light-emitting layer and the third light-emitting layer on the first surface.

17. The light-emitting element according to claim 16, characterized in that: A barrier layer is provided in the gap between the first wavelength conversion layer and the second wavelength conversion layer.

18. The light-emitting element according to claim 1, characterized in that: The rotation angle of the rotationally symmetric figure includes 90 degrees or 180 degrees.

19. A light-emitting device, characterized in that: Includes the light-emitting element as described in any one of claims 1-18.

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