Micro LED chip and manufacturing method thereof

Abstract

This application discloses a micro-LED chip and its manufacturing method. The invention comprises a buffer layer, an unintentionally doped layer, a first-type conductive layer, an active region, a second-type conductive layer, a reflective structure, a protective layer, and a first electrode and a second electrode, which are sequentially deposited on a first surface of a substrate. The first electrode is electrically connected to the first-type conductive layer, and the second electrode is electrically connected to the second-type conductive layer. Furthermore, a concave and convex surface is provided around the micro-LED chip. The technical solution provided by the invention not only changes the light emission angle of the micro-LED chip, making the light more concentrated and reducing the mutual influence of the display effect with nearby chips, but also creates a better color mixing effect on the surface. It also effectively avoids the loss of light-emitting area during the chip manufacturing process, effectively improving the luminous efficiency of the micro-LED chip.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a micro LED chip and a manufacturing method thereof. Background Art

[0002] Micro LED displays (Micro LED displays) are a next-generation display technology built on miniaturized LED arrays. This involves thinning, miniaturizing, and organizing the LED structure into an array, resulting in a volume approximately 1% the size of current mainstream LEDs. Each pixel can be addressed and individually driven to emit light, reducing the distance between pixels from millimeters to microns. Inheriting the characteristics of LEDs, Micro LEDs offer advantages such as low power consumption, high brightness, ultra-high resolution and color saturation, fast response, exceptional power efficiency, long lifespan, and high efficiency. Their power consumption is approximately 10% of that of LCDs and 50% of that of OLEDs. Compared to OLEDs, which are also self-luminous displays, Micro LEDs offer 30 times higher brightness and a resolution of 1500 PPI (pixel density), five times the 300 PPI of the OLED panels used in the Apple Watch. Furthermore, they offer superior material stability and no image burn-in.

[0003] With the continuous advancement of science and technology, Micro LED has developed into a hot topic in future display technologies, but its technical difficulties are numerous and complex. RGB technology provides the best display effects. Traditional RGB uses an array of microscopic light-emitting elements in three colors, transferred to a receiving substrate, where three RGB elements are planarly clustered together to create an RGB effect. However, with Micro LED technology, the chip size is very small, resulting in very close spacing between the chips. As a result, the distance between each RGB group is small, resulting in color mixing and preventing the full RGB effect. Furthermore, the process of transferring and mixing each RGB group in large quantities is too complex, resulting in low production yield and high production costs. Summary of the Invention

[0004] In view of this, the present invention provides a micro LED chip and a manufacturing method thereof, wherein a concave and convex surface is arranged around the micro LED chip, which can not only change the light output angle of the micro LED chip, making the light more concentrated, reducing the mutual influence of the display effect with the chips at close range, forming a better color mixing effect on the surface, but also effectively avoid the loss of the light-emitting area during the chip manufacturing process, and effectively improve the luminous efficiency of the micro LED chip.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A micro LED chip, comprising:

[0007] a substrate having a first surface;

[0008] an epitaxial light-emitting structure disposed on the first surface, the epitaxial light-emitting structure comprising a buffer layer, an unintentionally doped layer, a first-type conductive layer, an active region, and a second-type conductive layer sequentially deposited on the first surface;

[0009] a reflective structure provided on a surface of the second-type conductive layer facing away from the active area;

[0010] a protective layer provided on a surface of the reflective structure facing away from the second-type conductive layer;

[0011] a first electrode and a second electrode provided on a surface of the protective layer facing away from the reflective structure, the first electrode being electrically connected to the first-type conductive layer, and the second electrode being electrically connected to the second-type conductive layer;

[0012] A concave-convex surface is provided around the micro LED chip, and the radius of the concavemost point of the concave-convex surface in the area below the unintentionally doped layer and close to the buffer layer is larger than the radius of the concavemost point of the concave-convex surface on the side of the first type conductive layer toward the protective layer.

[0013] Preferably, in the above-mentioned micro LED chip, the concave-convex curved surface portion has a regular curved surface, and the radius of the most concave part of the concave-convex curved surface is not greater than 2 μm.

[0014] Preferably, the above-mentioned micro LED chip further comprises:

[0015] A transparent conductive structure is provided between the second-type conductive layer and the reflective structure.

[0016] Preferably, in the above-mentioned micro LED chip, the transparent conductive structure includes: a transparent conductive layer and / or a barrier layer.

[0017] Preferably, in the above-mentioned micro LED chip, the transparent conductive structure is a composite structure of a single transparent conductive layer and a single barrier layer, or an alternating stacking structure of multiple transparent conductive layers and multiple barrier layers, or a single-layer circular structure of the transparent conductive layer, or a single-layer circular structure of the barrier layer.

[0018] Preferably, in the above-mentioned micro LED chip, the material of the barrier layer includes any one or more combinations of Ti, W, Pt, Cr and Ni.

[0019] Preferably, in the above-mentioned micro LED chip, the material of the reflective structure is a metal reflective material, or a non-metallic DBR reflective material, or a composite material of the metal reflective material and the non-metallic DBR reflective material.

[0020] Preferably, in the above-mentioned micro LED chip, the metal reflective material is any one or more combinations of Au, Ag, Al, Pt and Cu.

[0021] Preferably, in the above-mentioned micro LED chip, it further comprises: a first conductive channel, a second conductive channel, and an insulating layer provided on the inner side wall of the first conductive channel;

[0022] The first conductive channel penetrates the protective layer, the reflective structure, the second-type conductive layer and the active area, so that the first electrode is electrically connected to the first-type conductive layer through the first conductive channel; the second conductive channel penetrates the protective layer and the reflective structure, so that the second electrode is electrically connected to the second-type conductive layer through the second conductive channel.

[0023] The present invention also provides a method for manufacturing a micro LED chip, the method comprising:

[0024] providing a substrate having a first surface;

[0025] forming an epitaxial light-emitting structure on the first surface, the epitaxial light-emitting structure comprising a buffer layer, an unintentionally doped layer, a first-type conductive layer, an active area, and a second-type conductive layer sequentially deposited on the first surface;

[0026] forming a reflective structure on a surface of the second-type conductive layer facing away from the active area;

[0027] forming a protective layer on a surface of the reflective structure facing away from the second-type conductive layer;

[0028] forming a first electrode and a second electrode on a surface of the protective layer facing away from the reflective structure, wherein the first electrode is electrically connected to the first-type conductive layer, and the second electrode is electrically connected to the second-type conductive layer;

[0029] A concave-convex surface is provided around the micro LED chip, and the radius of the concavemost point of the concave-convex surface in the area below the unintentionally doped layer and close to the buffer layer is larger than the radius of the concavemost point of the concave-convex surface on the side of the first type conductive layer toward the protective layer.

[0030] From the above description, it can be seen that in the micro LED chip and its manufacturing method provided by the technical solution of the present invention, by arranging the first electrode and the second electrode on the same side of the epitaxial light-emitting structure and forming electrical connections with the corresponding conductive layers respectively, the loss of the light-emitting area during the chip manufacturing process can be effectively avoided, the luminous efficiency of the micro LED chip can be effectively improved, and the size of the micro LED chip can be further reduced, thereby further improving the integration of the micro light-emitting diode device and improving the display resolution.

[0031] Furthermore, a concave-convex surface is provided around the micro-LED chip. The radius of the concave portion of the surface below the unintentionally doped layer and near the buffer layer is greater than the radius of the concave portion of the surface on the side of the first-type conductive layer facing the protective layer. This not only changes the light output angle of the micro-LED chip, concentrating the light, but also reduces the impact of light on the display effect with nearby chips, and achieves a better color mixing effect on the surface.

[0032] Furthermore, by providing a composite structure of a transparent conductive layer and a barrier layer between the reflective structure and the epitaxial light-emitting structure, a better ODR structure can be formed and the reflector metal can be effectively prevented from diffusing into the epitaxial structure and affecting the light-emitting efficiency of the epitaxial structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0034] The structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not intended to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size, without affecting the efficacy and objectives that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0035] Figure 1 A schematic structural diagram of a micro LED chip provided by an embodiment of the present invention;

[0036] Figure 2 A top view of a micro LED chip provided by an embodiment of the present invention;

[0037] Figure 3-Figure 12 A process flow chart of a method for manufacturing a micro LED chip provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0040] refer to Figure 1 and Figure 2 , Figure 1 This is a schematic structural diagram of a micro LED chip provided by an embodiment of the present invention. Figure 2 A top view of a micro LED chip provided by an embodiment of the present invention.

[0041] like Figure 1 and Figure 2 As shown, the micro LED chip includes:

[0042] The substrate 10 has a first surface and a second surface opposite to each other; the substrate 10 may be a sapphire substrate or a silicon substrate.

[0043] An epitaxial light-emitting structure 11 is provided on the first surface, and the epitaxial light-emitting structure 11 includes a buffer layer 111, an unintentionally doped layer 112, a first-type conductive layer 113, an active area 114, and a second-type conductive layer 115 deposited in sequence on the first surface; the material of the active area 114 can be AlGaInN, AlGaInP, AlGaInAsP or other III-V compounds.

[0044] A reflective structure 12 is provided on the surface of the second-type conductive layer 115 on the side facing away from the active area 114; the material of the reflective structure 12 can be a metal reflective material, a non-metallic DBR reflective material, or a composite material of the metal reflective material and the non-metallic DBR reflective material; the metal reflective material can be any one or more combinations of Au, Ag, Al, Pt and Cu.

[0045] A protective layer 13 provided on a surface of the reflective structure 12 facing away from the second-type conductive layer 115;

[0046] A first electrode 16 and a second electrode 17 are provided on a surface of the protective layer 13 facing away from the reflective structure 12 , wherein the first electrode 16 is electrically connected to the first-type conductive layer 113 , and the second electrode 17 is electrically connected to the second-type conductive layer 115 ;

[0047] A concave-convex surface 20 is provided around the micro LED chip, and the radius of the concavemost point of the concave-convex surface 20 in the area below the unintentionally doped layer 112 and close to the buffer layer 111 is larger than the radius of the concavemost point of the concave-convex surface 20 on the side of the first-type conductive layer 113 toward the protective layer 13.

[0048] The concave-convex surface 20 has a regular curved surface, and the radius of the most concave part of the concave-convex surface 20 is no more than 2 μm.

[0049] The present invention forms a concave-convex curved surface 20 with a larger bottom and a smaller top around the micro LED chip, which can not only change the light output angle of the micro LED, making the light more concentrated, but also reduce the mutual influence of the display effect with nearby chips, and form a better color mixing effect on the surface of the micro LED.

[0050] based on Figure 1 The micro LED chip further includes:

[0051] A transparent conductive structure 18 is provided between the second-type conductive layer and the reflective structure.

[0052] The transparent conductive structure 18 is disposed between the reflective structure 12 and the second-type conductive layer 115. The transparent conductive structure 18 may be a transparent conductive layer, a barrier layer, or a composite layer of a transparent conductive layer and a barrier layer. The barrier layer may be made of any one or more of Ti, W, Pt, Cr, and Ni.

[0053] Furthermore, the transparent conductive structure 18 can be a composite structure of a single transparent conductive layer and a single barrier layer, or an alternating stacked structure of multiple transparent conductive layers and multiple barrier layers, or a single-layer cyclic structure of the transparent conductive layer, or a single-layer cyclic structure of the barrier layer.

[0054] In the embodiment of the present invention, by providing a composite structure of a transparent conductive layer and a barrier layer between the reflective structure 12 and the epitaxial light-emitting structure 11, a better ODR structure can be formed and the reflector metal can be effectively prevented from diffusing into the epitaxial structure and affecting the luminous efficiency of the epitaxial structure.

[0055] based on Figure 1 The micro LED chip further includes:

[0056] A first conductive channel 14, a second conductive channel 15, and an insulating layer 141 provided on the inner sidewall of the first conductive channel 14;

[0057] The first conductive channel 14 penetrates the protective layer 13, the reflective structure 12, the transparent conductive structure 18, the second-type conductive layer 115 and the active area 114, so that the first electrode 16 is electrically connected to the first-type conductive layer 113 through the first conductive channel 14; the second conductive channel 15 penetrates the protective layer 13, the reflective structure 12 and the transparent conductive structure 18, so that the second electrode 17 is electrically connected to the second-type conductive layer 115 through the second conductive channel 15.

[0058] In an embodiment of the present invention, the epitaxial light-emitting structure 11 includes at least a first-type conductive layer 113, an active area 114 and a second-type conductive layer 115; the first-type conductive layer 113 can be an N-type conductive layer, and the second-type conductive layer 115 can be a P-type conductive layer, or the first-type conductive layer 113 can be a P-type conductive layer, and the second-type conductive layer 115 can be an N-type conductive layer.

[0059] In the embodiment of the present invention, the micro LED chip includes at least two electrodes, and the two electrodes are arranged on the same side of the epitaxial light-emitting structure 11, and the area of ​​the two electrodes is not less than 50% of the area of ​​the micro LED chip.

[0060] In an embodiment of the present invention, the operating voltage of the micro LED chip is set within a range of 1.5V-3.8V; and the operating current is set within a range of 1mA to 20mA.

[0061] From the above description, it can be seen that in the micro LED chip provided by the technical solution of the present invention, by arranging the first electrode and the second electrode on the same side of the epitaxial light-emitting structure and forming electrical connections with the corresponding conductive layers respectively, the loss of the light-emitting area during the chip manufacturing process can be effectively avoided, the luminous efficiency of the micro LED chip can be effectively improved, and the size of the micro LED chip can be further reduced, thereby further improving the integration of the micro light-emitting diode device and improving the display resolution.

[0062] Furthermore, a concave-convex surface is provided around the micro-LED chip. The radius of the concave portion of the surface below the unintentionally doped layer and near the buffer layer is greater than the radius of the concave portion of the surface on the side of the first-type conductive layer facing the protective layer. This not only changes the light output angle of the micro-LED chip, concentrating the light, but also reduces the impact of light on the display effect with nearby chips, and achieves a better color mixing effect on the surface.

[0063] Furthermore, by providing a composite structure of a transparent conductive layer and a barrier layer between the reflective structure and the epitaxial light-emitting structure, a better ODR structure can be formed and the reflector metal can be effectively prevented from diffusing into the epitaxial structure and affecting the light-emitting efficiency of the epitaxial structure.

[0064] Based on the above embodiment, another embodiment of the present invention further provides a method for manufacturing a micro LED chip, such as Figures 1-12 As shown, Figure 3-Figure 12 A process flow chart of a method for manufacturing a micro LED chip provided by an embodiment of the present invention, the manufacturing method comprising:

[0065] Step S11: Figure 3 As shown, a substrate 10 is provided, wherein the substrate 10 has a first surface; the substrate 10 may be a sapphire substrate or a silicon substrate;

[0066] Step S12: Figure 4-Figure 8 As shown, an epitaxial light-emitting structure 11 is formed on the first surface, and the epitaxial light-emitting structure 11 includes a buffer layer 111, an unintentionally doped layer 112, a first-type conductive layer 113, an active region 114, and a second-type conductive layer 115 deposited in sequence on the first surface;

[0067] The method for forming the epitaxial light-emitting structure 11 includes:

[0068] First, if Figure 4 As shown, a buffer layer 111 is formed on the first surface of the substrate 10;

[0069] Then, if Figure 5 As shown, an unintentionally doped layer 112 is formed on the surface of the buffer layer 111 facing away from the substrate 10;

[0070] Then, if Figure 6 As shown, a first type conductive layer 113 is formed on a surface of the unintentionally doped layer 112 facing away from the buffer layer 111;

[0071] Then, if Figure 7 As shown, an active region 114 is formed on a surface of the first-type conductive layer 113 facing away from the unintentionally doped layer 112 ; the material of the active region 114 may be AlGaInN, AlGaInP, AlGaInAsP or other III-V compounds;

[0072] Finally, if Figure 8 As shown, a second-type conductive layer 115 is formed on a surface of the active region 114 that is away from the first-type conductive layer 113 .

[0073] It should be noted that the epitaxial light-emitting structure 11 includes at least a first-type conductive layer 113, an active area 114 and a second-type conductive layer 115; the first-type conductive layer 113 can be an N-type conductive layer, the second-type conductive layer 115 can be a P-type conductive layer, or the first-type conductive layer 113 can be a P-type conductive layer, the second-type conductive layer 115 can be an N-type conductive layer.

[0074] Step S13: Figure 9 As shown, a transparent conductive structure 18 is formed on a surface of the second-type conductive layer 115 that is away from the active area 114 ;

[0075] The transparent conductive structure 18 may be a transparent conductive layer, a barrier layer, or a composite layer of a transparent conductive layer and a barrier layer. The barrier layer may be made of any one or more combinations of Ti, W, Pt, Cr, and Ni.

[0076] Furthermore, the transparent conductive structure 18 can be a composite structure of a single transparent conductive layer and a single barrier layer, or an alternating stacked structure of multiple transparent conductive layers and multiple barrier layers, or a single-layer cyclic structure of the transparent conductive layer, or a single-layer cyclic structure of the barrier layer.

[0077] In the embodiment of the present invention, by providing a composite structure of a transparent conductive layer and a barrier layer between the reflective structure 12 and the epitaxial light-emitting structure 11, a better ODR structure can be formed and the reflector metal can be effectively prevented from diffusing into the epitaxial structure and affecting the luminous efficiency of the epitaxial structure.

[0078] Step S14: Figure 10 As shown, a reflective structure 12 is formed on a surface of the transparent conductive structure 18 facing away from the second-type conductive layer 115 ;

[0079] The material of the reflective structure 12 can be a metal reflective material, a non-metallic DBR reflective material, or a composite material of the metal reflective material and the non-metallic DBR reflective material. The metal reflective material can be any one or more combinations of Au, Ag, Al, Pt and Cu.

[0080] Step S15: Figure 11 As shown, a protective layer 13 is formed on the surface of the reflective structure 12 on the side away from the transparent conductive structure 18;

[0081] Step S16: Figure 12As shown, a first conductive channel 14 is formed on the protective layer 13, the reflective structure 12, the transparent conductive layer 18, the second-type conductive layer 115 and the active area 114 by photolithography technology, and an insulating layer 141 is formed on the inner sidewall of the first conductive channel 14; a second conductive channel 15 is formed on the protective layer 13 by photolithography technology;

[0082] Step S17: Figure 1 As shown, a first electrode 16 and a second electrode 17 are formed on a surface of the protective layer 13 facing away from the reflective structure 12 , the first electrode 16 is electrically connected to the first-type conductive layer 113 , and the second electrode 17 is electrically connected to the second-type conductive layer 115 ;

[0083] The first conductive channel 14 penetrates the protective layer 13, the reflective structure 12, the transparent conductive structure 18, the second-type conductive layer 115 and the active area 114, so that the first electrode 16 is electrically connected to the first-type conductive layer 113 through the first conductive channel 14; the second conductive channel 15 penetrates the protective layer 13, the reflective structure 12 and the transparent conductive structure 18, so that the second electrode 17 is electrically connected to the second-type conductive layer 115 through the second conductive channel 15.

[0084] In an embodiment of the present invention, a concave-convex surface 20 is provided around the micro LED chip, and the radius of the concavemost point of the concave-convex surface 20 in the area below the unintentionally doped layer 112 and close to the buffer layer 111 is larger than the radius of the concavemost point of the concave-convex surface on the side of the first-type conductive layer 113 toward the protective layer 13.

[0085] The concave-convex surface 20 has a regular curved surface, and the radius of the most concave part of the concave-convex surface 20 is no more than 2 μm.

[0086] The present invention forms a concave-convex curved surface 20 with a larger bottom and a smaller top around the micro LED chip, which can not only change the light output angle of the micro LED, making the light more concentrated, but also reduce the mutual influence of the display effect with nearby chips, and form a better color mixing effect on the surface of the micro LED.

[0087] In the embodiment of the present invention, the micro LED chip includes at least two electrodes, and the two electrodes are arranged on the same side of the epitaxial light-emitting structure 11, and the area of ​​the two electrodes is not less than 50% of the area of ​​the micro LED chip.

[0088] In an embodiment of the present invention, the operating voltage of the micro LED chip is set within a range of 1.5V-3.8V; and the operating current is set within a range of 1mA to 20mA.

[0089] From the above description, it can be seen that in the method for manufacturing a micro LED chip provided by the technical solution of the present invention, by arranging the first electrode and the second electrode on the same side of the epitaxial light-emitting structure and forming electrical connections with the corresponding conductive layers respectively, the loss of the light-emitting area during the chip manufacturing process can be effectively avoided, the luminous efficiency of the micro LED chip can be effectively improved, and the size of the micro LED chip can be further reduced, thereby further improving the integration of the micro light-emitting diode device and improving the display resolution.

[0090] Furthermore, a concave-convex surface is provided around the micro-LED chip. The radius of the concave portion of the surface below the unintentionally doped layer and near the buffer layer is greater than the radius of the concave portion of the surface on the side of the first-type conductive layer facing the protective layer. This not only changes the light output angle of the micro-LED chip, concentrating the light, but also reduces the impact of light on the display effect with nearby chips, and achieves a better color mixing effect on the surface.

[0091] Furthermore, by providing a composite structure of a transparent conductive layer and a barrier layer between the reflective structure and the epitaxial light-emitting structure, a better ODR structure can be formed and the reflector metal can be effectively prevented from diffusing into the epitaxial structure and affecting the light-emitting efficiency of the epitaxial structure.

[0092] The various embodiments in this specification are described in a progressive, parallel, or progressive and parallel manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0093] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such article or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the article or device comprising the aforementioned elements.

[0094] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A micro LED chip, characterized in that: The micro LED chip includes: a substrate having a first surface; an epitaxial light-emitting structure disposed on the first surface, the epitaxial light-emitting structure comprising a buffer layer, an unintentionally doped layer, a first-type conductive layer, an active region, and a second-type conductive layer sequentially deposited on the first surface; a reflective structure provided on a surface of the second-type conductive layer facing away from the active area; a protective layer provided on a surface of the reflective structure facing away from the second-type conductive layer; a first electrode and a second electrode provided on a surface of the protective layer facing away from the reflective structure, the first electrode being electrically connected to the first-type conductive layer, and the second electrode being electrically connected to the second-type conductive layer; A concave-convex curved surface is provided around the micro LED chip, and the radius of the concavemost point of the concave-convex curved surface in a region below the unintentionally doped layer and close to the buffer layer is larger than the radius of the concavemost point of the concave-convex curved surface on the side of the first-type conductive layer facing the protective layer; The concave-convex curved surface portion has a regular curved surface, and the radius of the most concave part of the concave-convex curved surface is no more than 2 μm.

2. The micro LED chip according to claim 1, characterized in that: Also includes: A transparent conductive structure is provided between the second-type conductive layer and the reflective structure.

3. The micro LED chip according to claim 2, wherein: The transparent conductive structure includes: a transparent conductive layer and / or a barrier layer.

4. The micro LED chip according to claim 3, wherein: The transparent conductive structure is a composite structure of a single transparent conductive layer and a single barrier layer, or an alternating stacked structure of multiple transparent conductive layers and multiple barrier layers, or a single-layer cyclic structure of the transparent conductive layer, or a single-layer cyclic structure of the barrier layer.

5. The micro LED chip according to claim 4, characterized in that: The material of the barrier layer includes any one or more combinations of Ti, W, Pt, Cr and Ni.

6. The micro LED chip according to claim 1, wherein: The material of the reflective structure is a metal reflective material, or a non-metallic DBR reflective material, or a composite material of the metal reflective material and the non-metallic DBR reflective material.

7. The micro LED chip according to claim 6, characterized in that: The metal reflective material is any one or more combinations of Au, Ag, Al, Pt and Cu.

8. The micro LED chip according to claim 1, wherein: Also includes: a first conductive channel, a second conductive channel, and an insulating layer provided on an inner sidewall of the first conductive channel; The first conductive channel penetrates the protective layer, the reflective structure, the second-type conductive layer and the active area, so that the first electrode is electrically connected to the first-type conductive layer through the first conductive channel; the second conductive channel penetrates the protective layer and the reflective structure, so that the second electrode is electrically connected to the second-type conductive layer through the second conductive channel.

9. A method for manufacturing a micro LED chip, characterized in that: The production method comprises: providing a substrate having a first surface; forming an epitaxial light-emitting structure on the first surface, the epitaxial light-emitting structure comprising a buffer layer, an unintentionally doped layer, a first-type conductive layer, an active area, and a second-type conductive layer sequentially deposited on the first surface; forming a reflective structure on a surface of the second-type conductive layer facing away from the active area; forming a protective layer on a surface of the reflective structure facing away from the second-type conductive layer; forming a first electrode and a second electrode on a surface of the protective layer facing away from the reflective structure, wherein the first electrode is electrically connected to the first-type conductive layer, and the second electrode is electrically connected to the second-type conductive layer; A concave-convex curved surface is provided around the micro LED chip, and the radius of the most concave part of the concave-convex curved surface in the area below the unintentionally doped layer and close to the buffer layer is larger than the radius of the most concave part of the concave-convex curved surface on the side of the first type conductive layer toward the protective layer; the concave-convex curved surface portion has a regular curved surface, and the radius of the most concave part of the concave-convex curved surface is not greater than 2um.

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