LED chip and manufacturing method thereof

Abstract

The application provides an LED chip and a manufacturing method thereof. The second type of extension electrodes are provided with a middle extension electrode, and the rest of the second type of extension electrodes are distributed on both sides of the middle extension electrode with the middle extension electrode as a middle axis. The first type of extension electrodes are distributed on both sides of the middle extension electrode with the middle extension electrode as a middle axis. The first type of extension electrodes and the rest of the second type of extension electrodes are alternately distributed on both sides of the middle extension electrode. When the current flows through the second electrode (i.e. P electrode), the current preferentially passes through the middle extension electrode, and the radiative recombination of electrons and holes is quickly realized. Meanwhile, the first type of extension electrodes and the second type of extension electrodes are alternately and uniformly arranged on both sides of the middle extension electrode of the second electrode, so that the trend of current concentration on the middle extension electrode is alleviated, and the current is uniformly diffused on the light-emitting mesa.

Description

Technical Field

[0001] This invention relates to the field of light-emitting diodes, and more particularly to an LED chip and its manufacturing method. Background Technology

[0002] With the rapid development of LED technology and the gradual improvement of LED luminous efficacy, LED applications are becoming increasingly widespread, and people are paying more and more attention to the development prospects of LEDs in displays. The LED chip, as the core component of an LED lamp, functions to convert electrical energy into light energy. Specifically, it includes an epitaxial wafer and N-type and P-type electrodes respectively disposed on the epitaxial wafer. The epitaxial wafer includes a P-type semiconductor layer, an N-type semiconductor layer, and an active layer located between the N-type and P-type semiconductor layers. When current flows through the LED chip, holes in the P-type semiconductor and electrons in the N-type semiconductor move towards the active layer and recombine there, causing the LED chip to emit light.

[0003] As market demand for higher brightness LEDs increases, chip sizes are becoming larger, and drive currents are also increasing to achieve high-power LEDs. This necessitates continuous improvement and optimization of chip structures; currently, chip structures employing various electrode optimizations have become the mainstream structure for ultra-brightness chips; however, issues such as current congestion and poor reliability of the electrodes still exist.

[0004] In view of this, in order to overcome the above-mentioned defects of existing LED chips, the inventor has specially designed an LED chip and its manufacturing method, which leads to this invention. Summary of the Invention

[0005] The purpose of this invention is to provide an LED chip and its manufacturing method to solve the problems of current congestion and electrode reliability in LED chips.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An LED chip, comprising:

[0008] Substrate;

[0009] An epitaxial stack disposed on the surface of the substrate includes at least a first type semiconductor layer, an active region, and a second type semiconductor layer stacked sequentially along a first direction, and a local area of ​​the epitaxial stack is etched to a portion of the first type semiconductor layer to form a groove and a mesa; the first direction is perpendicular to the substrate and extends from the substrate to the epitaxial stack.

[0010] The first electrode is stacked on the exposed portion of the groove;

[0011] The second electrode is stacked on the surface of the mesa;

[0012] Viewed from above, the first electrode has a first-type extended electrode that is connected to it and extends along the direction of the second electrode; the second electrode has a plurality of second-type extended electrodes that are connected to it and extend along the direction of the first electrode.

[0013] The number of the second type of extended electrodes is odd; and the second type of extended electrode has a middle extended electrode, with the remaining second type of extended electrodes distributed in pairs on both sides of the middle extended electrode with the middle extended electrode as the central axis.

[0014] The number of the first type of extended electrodes is even, and the first type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the central axis; and the first type of extended electrodes and the remaining second type of extended electrodes are alternately distributed on both sides of the intermediate extended electrode.

[0015] Preferably, the second type of extended electrode has the intermediate extended electrode, and the remaining second type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the axis of symmetry.

[0016] Preferably, the first type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the axis of symmetry.

[0017] Preferably, in the extension direction from the second electrode to the first electrode, the distance between each second type extended electrode and the intermediate extended electrode gradually increases.

[0018] Preferably, the distance between each of the second type extended electrodes and the adjacent first type extended electrode gradually increases.

[0019] Preferably, in the extension direction from the second electrode to the first electrode, the thickness of the second type extended electrode gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0020] Preferably, in the extension direction from the first electrode to the second electrode, the thickness of the first type of extended electrode gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0021] Preferably, in the extension direction from the second electrode to the first electrode, the thickness of the intermediate extended electrode and the remaining second-type extended electrodes gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0022] Preferably, the number of the second type of extended electrodes is 3, and the number of the first type of extended electrodes is 2.

[0023] Preferably, it further includes a passivation layer, wherein the passivation layer covers the epitaxial stack and has a first through-hole and a second through-hole, the first through-hole corresponding to the first electrode and the second through-hole corresponding to the second electrode.

[0024] Preferably, the first type of semiconductor layer includes an N-type semiconductor layer, and the second type of semiconductor layer includes a P-type semiconductor layer.

[0025] Preferably, the epitaxial stack has at least one substrate exposed portion extending from the second type semiconductor layer through the active region and the first type semiconductor layer to the substrate, wherein the passivation layer is stacked on the substrate in such a way that it is held in the substrate exposed portion.

[0026] Preferably, the exposed substrate portion surrounds the periphery of the epitaxial stack; and the passivation layer is stacked on the substrate in such a way that it is held in the exposed substrate portion and surrounds the periphery of the epitaxial stack.

[0027] The present invention also provides a method for manufacturing an LED chip, the method comprising the following steps:

[0028] Step S01: Provide a substrate;

[0029] Step S02: Stack an epitaxial layer on the surface of the substrate. The epitaxial layer includes a first type semiconductor layer, an active region, and a second type semiconductor layer stacked sequentially along a first direction. The first direction is perpendicular to the substrate and extends from the substrate to the epitaxial layer.

[0030] Step S03: Etch a local area of ​​the epitaxial stack to a portion of the first type semiconductor layer to form a groove and a mesa;

[0031] Step S04: A first type of extended electrode is fabricated in the groove, and a second type of extended electrode is fabricated on the platform, wherein the first type of extended electrode and the second type of extended electrode extend in opposite directions respectively;

[0032] From a top-down view, the number of the second type of extended electrodes is odd; and the second type of extended electrode has a central extended electrode, with the remaining second type of extended electrodes distributed in pairs on both sides of the central extended electrode with the central extended electrode as the central axis.

[0033] The number of the first type of extended electrodes is even, and the first type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the central axis; and the first type of extended electrodes and the remaining second type of extended electrodes are alternately distributed on both sides of the intermediate extended electrode.

[0034] Step S05: Deeply etch the edges of the epitaxial stack to expose the substrate.

[0035] Step S06: Grow a passivation layer, wherein the passivation layer covers the epitaxial stack by being stacked on the exposed portion of the substrate; and pattern the passivation layer to have a first via and a second via, wherein the first via exposes a portion of the first type extended electrode, and the second via exposes a portion of the second type extended electrode.

[0036] Step S07: Fabricate a first electrode and a second electrode; the first electrode is stacked on the first through hole; the second electrode is stacked on the second through hole.

[0037] Preferably, in the extension direction from the second electrode to the first electrode, the distance between each second-type extended electrode and the intermediate extended electrode gradually increases; the distance between each second-type extended electrode and the adjacent first-type extended electrode gradually increases.

[0038] Preferably, in the extension direction from the first electrode to the second electrode, the thickness of the first type of extended electrode gradually decreases, and the minimum thickness is at least more than half of the maximum thickness;

[0039] In the extension direction from the second electrode to the first electrode, the thickness of the intermediate extended electrode and the remaining second-type extended electrodes gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0040] Preferably, the exposed substrate portion surrounds the periphery of the epitaxial stack; and the passivation layer is stacked on the substrate in such a way that it is held in the exposed substrate portion and surrounds the periphery of the epitaxial stack.

[0041] As can be seen from the above technical solution, the LED chip provided by the present invention has the following features: the first electrode has a first-type extended electrode connected to it and extending along the direction of the second electrode; the second electrode has a plurality of second-type extended electrodes connected to it and extending along the direction of the first electrode; wherein the number of second-type extended electrodes is odd; and the second-type extended electrode has a central extended electrode, with the remaining second-type extended electrodes distributed in pairs on both sides of the central extended electrode with the central extended electrode as the central axis; the number of first-type extended electrodes is even, and the first-type extended electrodes are distributed in pairs on both sides of the central extended electrode with the central extended electrode as the central axis; and the first-type extended electrodes and the remaining second-type extended electrodes are alternately distributed on both sides of the central extended electrode. Therefore, when current flows into the second electrode (i.e., the P electrode), it preferentially passes through the central extended electrode, quickly achieving radiative recombination of electrons and holes to emit light; simultaneously, the alternating and uniform arrangement of the first-type and second-type extended electrodes on both sides of the central extended electrode of the second electrode mitigates the tendency of current concentration on the central extended electrode, allowing the current to diffuse uniformly across the light-emitting surface. Therefore, based on the above structure, the current congestion phenomenon caused by large driving current is solved, and the external quantum efficiency of LED is effectively improved.

[0042] Secondly, in the extension direction from the second electrode to the first electrode, the spacing between each of the second-type extended electrodes and the intermediate extended electrode gradually increases, which further allows the current to diffuse to the edge of the epitaxial stack, thereby achieving more uniform light emission from the LED chip. Simultaneously, by gradually decreasing the thickness of the second-type extended electrodes, and setting the minimum thickness to be at least half the maximum thickness, current congestion can be reduced, thus increasing current diffusion and reducing product costs.

[0043] As can be seen from the above technical solutions, the LED chip manufacturing method provided by the present invention achieves the beneficial effects of the LED chip, while its manufacturing process is simple and convenient, and easy to mass-produce. Attached Figure Description

[0044] 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 only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of the LED chip provided in an embodiment of the present invention;

[0046] Figure 2This is a top view schematic diagram of the LED chip provided in an embodiment of the present invention;

[0047] Figure 3 This is a top view schematic diagram of the LED chip provided in an embodiment of the present invention;

[0048] Figures 4.1 to 4.7 This is a schematic diagram of the structure corresponding to the steps of the LED chip manufacturing method provided in the embodiments of the present invention;

[0049] Symbols in the figure: 1. Substrate, 1.1. Exposed part of substrate, 2. Type I semiconductor layer, 3. Active region, 4. Type II semiconductor layer, 5. Passivation layer, 6. Second electrode, 6.1. Intermediate extension electrode, 6.2. Type II extension electrode, 7. First electrode, 7.1. Type I extension electrode, 8. Mesa, 9. Groove. Detailed Implementation

[0050] To make the content of this invention clearer, the following description, in conjunction with the accompanying drawings, further illustrates the invention. This invention is not limited to this specific embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0051] like Figure 1 As shown, an LED chip includes:

[0052] Substrate 1;

[0053] An epitaxial stack is disposed on the surface of substrate 1. The epitaxial stack includes at least a first type semiconductor layer 2, an active region 3 and a second type semiconductor layer 4 stacked sequentially along a first direction. A local area of ​​the epitaxial stack is etched to a portion of the first type semiconductor layer 2 to form a groove 9 and a mesa 8. The first direction is perpendicular to substrate 1 and points from substrate 1 to the epitaxial stack.

[0054] The first electrode 7 is stacked on the exposed portion of the groove 9;

[0055] The second electrode 6 is stacked on the surface of the mesa 8;

[0056] Viewed from above, the first electrode 7 has a first-type extended electrode 7.1 connected to it and extending along the direction of the second electrode 6; the second electrode 6 has a plurality of second-type extended electrodes 6.2 connected to it and extending along the direction of the first electrode 7.

[0057] The number of the second type of extended electrodes 6.2 is odd; and the second type of extended electrodes 6.2 has an intermediate extended electrode 6.1, with the remaining second type of extended electrodes 6.2 distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the intermediate axis.

[0058] The number of Type I extended electrodes 7.1 is even. The Type I extended electrodes 7.1 are distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the central axis. Furthermore, the Type I extended electrodes 7.1 and the remaining Type II extended electrodes 6.2 are alternately distributed on both sides of the intermediate extended electrode 6.1.

[0059] It should be noted that the embodiments of the present invention do not limit the number of the second type extended electrodes 6.2, as long as their total number is odd, nor do they limit the number of the first type extended electrodes 7.1, as long as their total number is even; as an example of this embodiment, such as Figure 2 , Figure 3 As shown, there are 2 Type I extended electrodes 7.1 and 3 Type II extended electrodes 6.2.

[0060] It is worth mentioning that the type of substrate 1 is not limited in the LED chip of this embodiment. For example, substrate 1 can be, but is not limited to, sapphire substrate 1, silicon substrate 1, etc. In addition, the types of the epitaxial stacked first type semiconductor layer 2, active region 3 and second type semiconductor layer 4 are also not limited in the LED chip of this embodiment. For example, the first type semiconductor layer 2 can be, but is not limited to, an N-type gallium nitride layer, and correspondingly, the second type semiconductor layer 4 can be, but is not limited to, a P-type gallium nitride layer.

[0061] It is worth mentioning that the material of the passivation layer 5 can be, but is not limited to, SiO2 (silicon dioxide).

[0062] In addition, the first electrode 7 and the second electrode 6 can be, but are not limited to, gold-tin electrodes.

[0063] like Figure 2 As shown, in this embodiment of the invention, the second type of extended electrode 6.2 has an intermediate extended electrode 6.1, and the remaining second type of extended electrodes 6.2 are distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the axis of symmetry.

[0064] In this embodiment of the invention, the first type of extended electrode 7.1 is distributed on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the axis of symmetry.

[0065] like Figure 3 As shown, in another embodiment of the present invention, in the extending direction from the second electrode 6 to the first electrode 7, the distance d between each second type extended electrode 6.2 and the intermediate extended electrode 6.1 gradually increases.

[0066] Furthermore, the distance between each second-type extended electrode 6.2 and the adjacent first-type extended electrode 7.1 gradually increases.

[0067] In this embodiment of the invention, in the extending direction from the second electrode 6 to the first electrode 7, the thickness of the second type extended electrode 6.2 gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0068] In this embodiment of the invention, the thickness of the first type extended electrode 7.1 gradually decreases in the extending direction from the first electrode 7 to the second electrode 6, and the minimum thickness is at least more than half of the maximum thickness.

[0069] In this embodiment of the invention, in the extending direction from the second electrode 6 to the first electrode 7, the thickness of the intermediate extended electrode 6.1 and the remaining second-type extended electrodes 6.2 gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0070] In this embodiment of the invention, a passivation layer 5 is further included, wherein the passivation layer 5 covers the epitaxial stack and has a first through hole and a second through hole, the first through hole corresponding to the first electrode 7 and the second through hole corresponding to the second electrode 6.

[0071] In this embodiment of the invention, the first type semiconductor layer 2 includes an N-type semiconductor layer, and the second type semiconductor layer 4 includes a P-type semiconductor layer.

[0072] In this embodiment of the invention, the epitaxial stack has at least one substrate exposed portion 1.1, which extends from the second type semiconductor layer 4 through the active region 3 and the first type semiconductor layer 2 to the substrate 1, wherein the passivation layer 5 is stacked on the substrate 1 in such a way that it is held in the substrate exposed portion 1.1.

[0073] In this embodiment of the invention, the substrate exposed portion 1.1 surrounds the periphery of the epitaxial stack; and the passivation layer 5 is stacked on the substrate 1 in such a way that it is held in the substrate exposed portion 1.1 and surrounds the periphery of the epitaxial stack.

[0074] This invention also provides a method for manufacturing an LED chip, the method comprising the following steps:

[0075] Step S01, as follows Figure 4.1 As shown, a substrate 1 is provided;

[0076] Step S02, as follows Figure 4.2 As shown, an epitaxial stack is stacked on the surface of substrate 1. The epitaxial stack includes a first type semiconductor layer 2, an active region 3 and a second type semiconductor layer 4 stacked sequentially along a first direction. The first direction is perpendicular to substrate 1 and points from substrate 1 to the epitaxial stack.

[0077] Step S03, as Figure 4.3 As shown, a local area of ​​the epitaxial stack is etched to a portion of the first type semiconductor layer 2 to form a groove 9 and a mesa 8;

[0078] Step S04, as Figure 4.4As shown, a first type of extended electrode 7.1 is fabricated in the groove 9, and a second type of extended electrode 6.2 is fabricated on the platform 8, wherein the first type of extended electrode 7.1 and the second type of extended electrode 6.2 extend in opposite directions respectively;

[0079] Looking down from above, as Figure 2 As shown, the number of the second type of extended electrodes 6.2 is odd; and the second type of extended electrodes 6.2 has an intermediate extended electrode 6.1, with the remaining second type of extended electrodes 6.2 distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the intermediate axis;

[0080] The number of Type I extended electrodes 7.1 is even, and the Type I extended electrodes 7.1 are distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the central axis; and the Type I extended electrodes 7.1 and the remaining Type II extended electrodes 6.2 are alternately distributed on both sides of the intermediate extended electrode 6.1.

[0081] Step S05, as follows Figure 4.5 As shown, the edges of the epitaxial stack are deeply etched to expose the substrate 1.1;

[0082] Step S06, as follows Figure 4.6 As shown, a passivation layer 5 is grown, and the passivation layer 5 covers the epitaxial stack by being stacked on the exposed portion 1.1 of the substrate; and the passivation layer 5 is patterned to have a first through hole and a second through hole, the first through hole exposes a first type extended electrode 7.1, and the second through hole exposes a second type extended electrode 6.2.

[0083] Step S07, as follows Figure 4.7 As shown, a first electrode 7 and a second electrode 6 are fabricated; the first electrode 7 is stacked on the first through hole; the second electrode 6 is stacked on the second through hole.

[0084] In this embodiment of the invention, in the extending direction from the second electrode 6 to the first electrode 7, the distance between each second type extended electrode 6.2 and the intermediate extended electrode 6.1 gradually increases; the distance between each second type extended electrode 6.2 and the adjacent first type extended electrode 7.1 gradually increases.

[0085] In this embodiment of the invention, in the extending direction from the first electrode 7 to the second electrode 6, the thickness of the first type extended electrode 7.1 gradually decreases, and the minimum thickness is at least more than half of the maximum thickness;

[0086] In the extension direction from the second electrode 6 to the first electrode 7, the thickness of the intermediate extended electrode 6.1 and the remaining second-type extended electrodes 6.2 gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

[0087] In this embodiment of the invention, the substrate exposed portion 1.1 surrounds the periphery of the epitaxial stack; and the passivation layer 5 is stacked on the substrate 1 in such a way that it is held in the substrate exposed portion 1.1 and surrounds the periphery of the epitaxial stack.

[0088] As can be seen from the above technical solution, the LED chip provided by the present invention has a first type of extended electrode 7.1 connected to the first electrode 7 and extending along the direction of the second electrode 6; the second electrode 6 has a plurality of second type extended electrodes 6.2 connected to the second electrode 7 and extending along the direction of the first electrode 7; wherein the number of second type extended electrodes 6.2 is odd; and the second type extended electrode 6.2 has an intermediate extended electrode 6.1, and the remaining second type extended electrodes 6.2 are distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the intermediate axis; the number of first type extended electrodes 7.1 is even, and the first type extended electrodes 7.1 are distributed in pairs on both sides of the intermediate extended electrode 6.1 with the intermediate extended electrode 6.1 as the intermediate axis; and the first type extended electrodes 7.1 and the remaining second type extended electrodes 6.2 are alternately distributed on both sides of the intermediate extended electrode 6.1. Therefore, when current flows in through the second electrode 6 (i.e., the P electrode), it preferentially passes through the intermediate extended electrode 6.1, rapidly achieving radiative recombination of electrons and holes for light emission. Simultaneously, the alternating and uniform arrangement of the first-type extended electrode 7.1 and the second-type extended electrode 6.2 on both sides of the intermediate extended electrode 6.1 of the second electrode 6 mitigates the current concentration tendency at the intermediate extended electrode 6.1, allowing the current to diffuse uniformly across the light-emitting mesa 8. Thus, based on the above structure, the current congestion phenomenon caused by large driving current is solved, and the external quantum efficiency of the LED is effectively improved.

[0089] Secondly, in the extension direction from the second electrode 6 to the first electrode 7, the spacing between each second-type extended electrode 6.2 and the intermediate extended electrode 6.1 gradually increases, which further allows the current to diffuse to the edge of the epitaxial stack, thereby achieving more uniform light emission from the LED chip. Simultaneously, by gradually decreasing the thickness of the second-type extended electrode 6.2, with the minimum thickness being at least half the maximum thickness, current congestion can be reduced, thus increasing current diffusion and reducing product costs.

[0090] As can be seen from the above technical solutions, the LED chip manufacturing method provided by the present invention achieves the beneficial effects of the LED chip, while its manufacturing process is simple and convenient, and easy to mass-produce.

[0091] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0092] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0093] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An LED chip, characterized in that, include: Substrate; An epitaxial stack disposed on the surface of the substrate includes at least a first type semiconductor layer, an active region, and a second type semiconductor layer stacked sequentially along a first direction, and a local area of ​​the epitaxial stack is etched to a portion of the first type semiconductor layer to form a groove and a mesa; the first direction is perpendicular to the substrate and extends from the substrate to the epitaxial stack. The first electrode is stacked on the exposed portion of the groove; The second electrode is stacked on the surface of the mesa; Viewed from above, the first electrode has a first-type extended electrode that is connected to it and extends along the direction of the second electrode; the second electrode has a plurality of second-type extended electrodes that are connected to it and extend along the direction of the first electrode. The number of the second type of extended electrodes is odd; and the second type of extended electrode has a middle extended electrode, with the remaining second type of extended electrodes distributed in pairs on both sides of the middle extended electrode with the middle extended electrode as the central axis. The number of the first type of extended electrodes is even, and the first type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the central axis; and the first type of extended electrodes and the remaining second type of extended electrodes are alternately distributed on both sides of the intermediate extended electrode. In the direction of extension from the second electrode to the first electrode, the distance between each second type extended electrode and the intermediate extended electrode gradually increases; In the direction of extension from the second electrode to the first electrode, the thickness of the second type of extended electrode gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

2. The LED chip according to claim 1, characterized in that, The second type of extended electrode has the intermediate extended electrode, and the remaining second type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the axis of symmetry.

3. The LED chip according to claim 1, characterized in that, The first type of extended electrode is distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the axis of symmetry.

4. The LED chip according to claim 1, characterized in that, The distance between each second-type extended electrode and the adjacent first-type extended electrode gradually increases.

5. The LED chip according to claim 1, characterized in that, In the extension direction from the first electrode to the second electrode, the thickness of the first type of extended electrode gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

6. The LED chip according to claim 2, characterized in that, In the extension direction from the second electrode to the first electrode, the thickness of the intermediate extended electrode and the remaining second-type extended electrodes gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

7. The LED chip according to claim 1, characterized in that, The second type of extended electrode has 3 electrodes, and the first type of extended electrode has 2 electrodes.

8. The LED chip according to claim 1, characterized in that, It also includes a passivation layer, wherein the passivation layer covers the epitaxial stack and has a first via and a second via, the first via corresponding to the first electrode and the second via corresponding to the second electrode.

9. A method for fabricating an LED chip, characterized in that, The preparation method includes the following steps: Step S01: Provide a substrate; Step S02: Stack an epitaxial layer on the surface of the substrate. The epitaxial layer includes a first type semiconductor layer, an active region, and a second type semiconductor layer stacked sequentially along a first direction. The first direction is perpendicular to the substrate and extends from the substrate to the epitaxial layer. Step S03: Etch a local area of ​​the epitaxial stack to a portion of the first type semiconductor layer to form a groove and a mesa; Step S04: A first type of extended electrode is fabricated in the groove, and a second type of extended electrode is fabricated on the platform, wherein the first type of extended electrode and the second type of extended electrode extend in opposite directions respectively; From a top-down view, the number of the second type of extended electrodes is odd; and the second type of extended electrode has a central extended electrode, with the remaining second type of extended electrodes distributed in pairs on both sides of the central extended electrode with the central extended electrode as the central axis. The number of the first type of extended electrodes is even, and the first type of extended electrodes are distributed in pairs on both sides of the intermediate extended electrode with the intermediate extended electrode as the central axis; and the first type of extended electrodes and the remaining second type of extended electrodes are alternately distributed on both sides of the intermediate extended electrode. Step S05: Deeply etch the edges of the epitaxial stack to expose the substrate. Step S06: Grow a passivation layer, wherein the passivation layer covers the epitaxial stack by being stacked on the exposed portion of the substrate; and pattern the passivation layer to have a first via and a second via, wherein the first via exposes a portion of the first type extended electrode, and the second via exposes a portion of the second type extended electrode. Step S07: Fabricate a first electrode and a second electrode; the first electrode is stacked on the first through hole; the second electrode is stacked on the second through hole; In the direction of extension from the second electrode to the first electrode, the distance between each second type extended electrode and the intermediate extended electrode gradually increases; In the extension direction from the first electrode to the second electrode, the thickness of the first type of extended electrode gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

10. The method for preparing an LED chip according to claim 9, characterized in that, The distance between each second-type extended electrode and the adjacent first-type extended electrode gradually increases.

11. The method for preparing an LED chip according to claim 9, characterized in that, In the extension direction from the second electrode to the first electrode, the thickness of the intermediate extended electrode and the remaining second-type extended electrodes gradually decreases, and the minimum thickness is at least more than half of the maximum thickness.

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