Preparation method of electrode, electrode structure, LED chip and preparation method of LED chip

Abstract

The invention provides an electrode preparation method, an electrode structure, an LED chip and a preparation method thereof, and relates to the technical field of semiconductor device preparation. The photoresist layer is controlled to warp by heating the temperature of a preparation environment, and then the prepared corresponding transition layer extends and fills the gap between the photoresist layer and the side wall of the laminated layer, so that the transition layer and the corresponding substrate are contacted and fixed, and the transition layer and the corresponding transparent conductive film layer are contacted and fixed. Therefore, the bonding area and the bonding strength between the electrode and the bearing structure thereof are improved, and the problem that the electrode is easy to fall off is solved. Moreover, according to the technical scheme provided by the invention, only the prepared first transition layer extends to cover the side wall of the first laminated layer, and the prepared first conductive layer does not need to cover the side wall of the first transition layer, so that the influence of the first electrode on the light-emitting brightness is reduced, and the high light-emitting brightness of the LED chip is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor device preparation, and more specifically, to an electrode preparation method, an electrode structure, an LED (Light Emitting Diode) chip and a preparation method thereof. Background Art

[0002] With the rapid development of LED technology and the gradual improvement of LED lighting efficiency, existing LED chips are widely used in the fields of electronics, optics, etc., and have made great progress in lighting, display, and digital. As the core component of LED lamps, the function of LED chips is to convert electrical energy into light energy. Generally, LED chips include a light-emitting epitaxial layer and an N-type electrode and a P-type electrode respectively arranged on the light-emitting epitaxial layer. The light-emitting epitaxial layer at least includes a P-type semiconductor layer, an N-type semiconductor layer, and an active layer located between the N-type semiconductor layer and the P-type semiconductor layer. When current passes through the LED chip, the holes in the P-type semiconductor and the electrons in the N-type semiconductor will move to the active layer and recombine in the active layer, so that the LED chip emits light. In existing LED chips, the bonding strength between the electrode and the light-emitting epitaxial layer is poor, and the problem of electrode detachment often occurs. Summary of the invention

[0003] In view of this, the present application provides an electrode preparation method, an electrode structure, an LED chip and a preparation method thereof, which effectively solves the technical problems existing in the prior art, improves the bonding strength between the electrode and its supporting structure, and thereby improves the problem of easy detachment of the electrode.

[0004] To achieve the above objectives, the technical solutions provided by this application are as follows:

[0005] A method for preparing an electrode, the preparation method comprising:

[0006] providing a substrate;

[0007] Preparing a photoresist layer on the surface of the substrate, wherein the photoresist layer includes an electrode hollowing;

[0008] An adhesion layer and a reflection layer are sequentially prepared in the electrode hollowing and stacked on the surface of the substrate, wherein the reflection layer is located on a side of the adhesion layer away from the substrate;

[0009] Heating the preparation environment temperature to a set temperature so that the photoresist layer is lifted at the side wall of the stack and separated from the side wall of the stack;

[0010] A transition layer is prepared on a side of the stack away from the substrate, wherein the transition layer fills a gap between the sidewall of the stack and the photoresist layer and contacts the substrate;

[0011] Preparing a conductive layer on the side of the transition layer away from the substrate;

[0012] The photoresist layer is removed to obtain an electrode, wherein the electrode includes the adhesion layer, the reflective layer, the transition layer and the conductive layer.

[0013] Optionally, the photoresist layer is a negative photoresist layer, wherein the stacking of the adhesion layer and the reflective layer is sequentially prepared in the electrode hollow on the surface of the substrate, comprising:

[0014] preparing an adhesion layer in the electrode hollowing out on the surface of the substrate,

[0015] A reflective layer is prepared to cover the sidewall of the adhesion layer and the surface of the side facing away from the substrate.

[0016] Based on the same inventive concept, the present application also provides an electrode structure applied to an LED chip, the electrode structure comprising:

[0017] A stack, a transition layer and a conductive layer are sequentially stacked on one side surface of a substrate, wherein the stack comprises an adhesion layer and a reflective layer sequentially stacked, the transition layer extends to cover the side wall of the stack and contacts the surface of the substrate, the conductive layer at most covers the surface of the transition layer facing away from the substrate, and the side wall of the transition layer is a curved surface concave toward the stack.

[0018] Based on the same inventive concept, the present application also provides a method for preparing an LED chip, the preparation method comprising:

[0019] Providing a substrate structure, the substrate structure comprising a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current blocking layer and a transparent conductive film layer stacked in sequence;

[0020] Preparing a photoresist layer on one side of the transparent conductive film layer of the substrate structure, wherein the photoresist layer includes a first electrode hollowing exposing the transparent conductive film layer;

[0021] A first electrode is prepared on the surface of the transparent conductive film layer in the first electrode hollowing, wherein the preparation method of the first electrode comprises: preparing a first stack of a first adhesion layer and a first reflective layer in sequence on the surface of the transparent conductive film layer in the first electrode hollowing, wherein the first reflective layer is located on the side of the first adhesion layer away from the transparent conductive film layer; heating the preparation environment temperature to a set temperature, so that the photoresist layer is peeled off at the side wall of the first stack and separated from the side wall of the first stack; preparing a first transition layer on the side of the first stack away from the transparent conductive film layer, wherein the first transition layer fills the gap between the side wall of the first stack and the photoresist layer and contacts the transparent conductive film layer; preparing a first conductive layer on the side of the first transition layer away from the transparent conductive film layer, wherein the first electrode comprises the first adhesion layer, the first reflective layer, the first transition layer and the first conductive layer;

[0022] The photoresist layer is removed.

[0023] Optionally, on one side of the transparent conductive film layer of the substrate structure, the substrate structure includes a step region exposing the first semiconductor layer, and the photoresist layer includes a second electrode hollow exposing the first semiconductor layer;

[0024] The second electrode hollowing is used to prepare the second electrode on the surface of the first semiconductor layer, wherein the preparation method of the second electrode includes: sequentially preparing a second stack of a second adhesion layer and a second reflective layer on the surface of the first semiconductor layer in the second electrode hollowing, the second reflective layer being located on the side of the second adhesion layer away from the first semiconductor layer; heating the preparation environment temperature to a set temperature so that the photoresist layer is peeled off at the side wall of the second stacking layer and separated from the side wall of the second stacking layer; preparing a second transition layer on the side of the second stacking layer away from the first semiconductor layer, the second transition layer fills the gap between the side wall of the second stacking layer and the photoresist layer and contacts the first semiconductor layer; preparing a second conductive layer on the side of the second transition layer away from the first semiconductor layer, the second electrode includes the second adhesion layer, the second reflective layer, the second transition layer and the second conductive layer.

[0025] Optionally, the second electrode and the first electrode are prepared simultaneously and by the same preparation method.

[0026] Optionally, the photoresist layer is a negative photoresist layer, wherein the first stack of a first adhesion layer and a first reflective layer is sequentially prepared in the first electrode hollow on the surface of the transparent conductive film layer, comprising:

[0027] A first adhesion layer is prepared in the first electrode hollow on the surface of the transparent conductive film layer,

[0028] Prepare a first reflective layer covering the sidewall of the first adhesion layer and the surface of the side facing away from the transparent conductive film layer;

[0029] And, the second stack of a second adhesion layer and a second reflective layer is sequentially prepared in the second electrode hollow on the surface of the first semiconductor layer, including:

[0030] A second adhesion layer is prepared in the second electrode hollow on the surface of the first semiconductor layer,

[0031] A second reflective layer is prepared to cover the sidewall of the second adhesion layer and a surface of the side facing away from the first semiconductor layer.

[0032] Optionally, the heating preparation environment temperature to a set temperature includes:

[0033] The preparation environment temperature is heated to a set temperature, wherein the set temperature range is 20-60°C.

[0034] Based on the same inventive concept, the present application also provides an LED chip, the LED chip comprising:

[0035] A substrate structure, the substrate structure comprising a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current blocking layer and a transparent conductive film layer stacked in sequence;

[0036] A first electrode is located on the side of the transparent conductive film layer facing away from the substrate, the first electrode includes a first stack, a first transition layer and a first conductive layer stacked in sequence, wherein the first stack includes a first adhesion layer and a first reflective layer stacked in sequence, the first transition layer extends to cover the side wall of the first stack and contacts the transparent conductive film layer, the first conductive layer covers at most the surface of the first transition layer on the side facing away from the substrate, and the side wall of the first transition layer is a curved surface concave toward the first stack.

[0037] Optionally, on one side of the transparent conductive film layer of the substrate structure, the substrate structure includes a step region exposing the first semiconductor layer, and the LED chip includes:

[0038] A second electrode is located at the step region and on the surface of the first semiconductor layer, the second electrode includes a second stack, a second transition layer and a second conductive layer stacked in sequence, wherein the second stack includes a second adhesion layer and a second reflective layer stacked in sequence, the second transition layer extends to cover the side wall of the second stack and contacts the first semiconductor layer, the second conductive layer covers at most the surface of the second transition layer on the side facing away from the substrate, and the side wall of the second transition layer is a curved surface concave toward the second stack.

[0039] Compared with the prior art, the technical solution provided by this application has at least the following advantages:

[0040] The present application provides an electrode preparation method, an electrode structure, an LED chip and a preparation method thereof, wherein the electrode preparation method comprises: providing a substrate; preparing a photoresist layer on the surface of the substrate, the photoresist layer comprising an electrode hollow; sequentially preparing a stack of an adhesion layer and a reflective layer in the electrode hollow on the surface of the substrate, the reflective layer being located on the side of the adhesion layer away from the substrate; heating the preparation environment temperature to a set temperature so that the photoresist layer is warped at the side wall of the stack and separated from the side wall of the stack; preparing a transition layer on the side of the stack away from the substrate, the transition layer filling the gap between the side wall of the stack and the photoresist layer and contacting the substrate; preparing a conductive layer on the side of the transition layer away from the substrate; removing the photoresist layer to obtain an electrode, the electrode comprising the adhesion layer, the reflective layer, the transition layer and the conductive layer.

[0041] And, the preparation method of the first electrode provided in the present application includes: preparing a first stack of a first adhesion layer and a first reflective layer in sequence on the surface of the transparent conductive film layer in the hollow of the first electrode, the first reflective layer being located on the side of the first adhesion layer away from the transparent conductive film layer; heating the preparation environment temperature to a set temperature so that the photoresist layer is warped at the side wall of the first stack and separated from the side wall of the first stack; preparing a first transition layer on the side of the first stack away from the transparent conductive film layer, the first transition layer fills the gap between the side wall of the first stack and the photoresist layer and contacts the transparent conductive film layer; preparing a first conductive layer on the side of the first transition layer away from the transparent conductive film layer, the first electrode includes the first adhesion layer, the first reflective layer, the first transition layer and the first conductive layer.

[0042] As can be seen from the above content, the technical solution provided by the present application controls the photoresist layer to be lifted by heating the preparation environment temperature, and then extends the corresponding transition layer to fill the gap between the photoresist layer and the side wall of the stack, and finally makes the transition layer contact and fix with the corresponding substrate, and makes the transition layer contact and fix with the corresponding transparent conductive film layer, thereby increasing the bonding area and bonding strength between the electrode and its supporting structure, and then improving the problem of easy electrode falling off. In addition, the technical solution provided by the present application only extends the prepared first transition layer to cover the side wall of the first stack, without the need to cover the side wall of the first transition layer with the prepared first conductive layer, which reduces the influence of the first electrode on the light brightness, and ensures that the light brightness of the LED chip is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] Figure 1 A flow chart of a method for preparing an electrode provided for implementation of the present application;

[0045] Figure 2a to Figure 2g for Figure 1 The structural schematic diagram corresponding to each step in the figure;

[0046] Figure 3 A flowchart of a method for preparing an LED chip provided in an embodiment of the present application;

[0047] Figure 4 A flowchart of a method for preparing an LED chip provided in an embodiment of the present application;

[0048] Figure 5a to Figure 5d for Figure 4 The structural schematic diagram corresponding to each step in the figure;

[0049] Figures 6a to 6d A schematic structural diagram corresponding to each step of a preparation process of a first electrode and a second electrode provided in an embodiment of the present application;

[0050] Figure 7 A schematic diagram of the structure of an LED chip provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] As described in the background technology, the LED chip includes a light-emitting epitaxial layer and an N-type electrode and a P-type electrode respectively arranged on the light-emitting epitaxial layer. The light-emitting epitaxial layer at least includes a P-type semiconductor layer, an N-type semiconductor layer, and an active layer located between the N-type semiconductor layer and the P-type semiconductor layer. When current passes through the LED chip, holes in the P-type semiconductor and electrons in the N-type semiconductor will move to the active layer and recombine in the active layer, so that the LED chip emits light. In existing LED chips, the bonding strength between the electrode and the light-emitting epitaxial layer is poor, and the problem of electrode detachment often occurs.

[0053] In particular, during the preparation process of LED chips and before they are shipped out of the factory, they usually need to be tested for performance, such as the push-pull force test of LED chips. When the existing LED chips are tested for push-pull force, the electrode often falls off due to the large force applied to the LED chip. Also, in the subsequent packaging process of the LED chips, the electrode often falls off during the electrode wire bonding packaging.

[0054] Based on this, the embodiments of the present application provide an electrode preparation method, an electrode structure, an LED chip and a preparation method thereof, which effectively solves the technical problems existing in the prior art, improves the bonding strength between the electrode and its supporting structure, and thereby improves the problem of easy detachment of the electrode.

[0055] To achieve the above purpose, the technical solution provided in the embodiment of the present application is as follows, specifically combined with Figures 1 to 7 The technical solution provided in the embodiments of the present application is described in detail.

[0056] refer to Figure 1 FIG. 1 is a flow chart of a method for preparing an electrode provided in an embodiment of the present application, wherein the method for preparing the electrode comprises:

[0057] S11. Provide a substrate.

[0058] S12, preparing a photoresist layer on the surface of the substrate, wherein the photoresist layer includes an electrode hollowing.

[0059] S13, sequentially preparing an adhesion layer and a reflection layer in the electrode hollow on the surface of the substrate, wherein the reflection layer is located on a side of the adhesion layer away from the substrate.

[0060] S14, heating the preparation environment temperature to a set temperature, so that the photoresist layer is warped at the side wall of the stack and separated from the side wall of the stack.

[0061] S15, preparing a transition layer on the side of the stack facing away from the substrate, wherein the transition layer fills the gap between the side wall of the stack and the photoresist layer and contacts the substrate.

[0062] S16, preparing a conductive layer on the side of the transition layer away from the substrate;

[0063] S17, removing the photoresist layer to obtain an electrode, wherein the electrode includes the adhesion layer, the reflective layer, the transition layer and the conductive layer.

[0064] It can be understood that the technical solution provided in the embodiment of the present application controls the photoresist layer to be lifted by heating the preparation environment temperature, and then extends the prepared transition layer to fill the gap between the photoresist layer and the side wall of the stack, and finally makes the transition layer contact and fix with the substrate, thereby increasing the bonding area and bonding strength between the electrode and the substrate, and thus improving the problem of the electrode falling off easily. In addition, the preparation method of the electrode provided in the embodiment of the present application is simple, and there is no need to increase the bonding strength by increasing the bonding area between the electrode and the substrate without restriction, so as to ensure that the production cost is low and the brightness of the light emitted from the substrate side is not affected.

[0065] Combination Figure 2a to Figure 2g The preparation method of the electrode provided in the embodiment of the present application is described in more detail. Figure 2a to Figure 2g for Figure 1 Schematic diagram of the corresponding structure of each step.

[0066] like Figure 2a As shown, corresponding to step S11 , a substrate 10 is provided.

[0067] like Figure 2b As shown, corresponding to step S12, a photoresist layer 20 is prepared on the surface of the substrate 10, and the photoresist layer 20 includes an electrode hollowing.

[0068] like Figure 2c As shown, corresponding to step S13 , an adhesion layer 31 and a reflection layer 32 are sequentially prepared in the electrode hollow on the surface of the substrate 10 , and the reflection layer 32 is located on the side of the adhesion layer 31 away from the substrate 10 .

[0069] In one embodiment of the present application, the adhesion layer provided in the embodiment of the present application can be prepared by selecting a material with good adhesion to the substrate, such as the adhesion of the material of the adhesion layer to the substrate is stronger than the adhesion of the material of the conductive layer to the substrate, thereby improving the bonding strength between the electrode and the substrate and improving the problem of easy detachment of the electrode.

[0070] Furthermore, the photoresist layer provided in the embodiment of the present application may be a negative photoresist layer, wherein the stacking of the adhesion layer and the reflective layer is sequentially prepared in the electrode hollow on the surface of the substrate, including: preparing the adhesion layer in the electrode hollow on the surface of the substrate, and preparing the reflective layer covering the side wall of the adhesion layer and the surface of the side away from the substrate. Figure 2c As shown, when the photoresist layer is selected to be a negative photoresist layer, when preparing the adhesion layer 31 and the reflective layer 32, the reflective layer 32 can be prepared as a structural layer covering the surface and side walls of the adhesion layer 31, thereby increasing the reflective area of ​​the reflective layer 32 and better reflecting the side light of the substrate 10 to improve the luminous brightness of the related devices.

[0071] It should be noted that the photoresist layer provided in the embodiment of the present application can also be a positive photoresist layer, thereby improving the application scope of the electrode preparation method provided in the present application, and the present application does not make any specific restrictions on this.

[0072] like Figure 2d As shown, corresponding to step S14, the preparation environment temperature is heated to a set temperature, so that the photoresist layer 20 is warped at the sidewall of the stack and separated from the sidewall of the stack.

[0073] In one embodiment of the present application, the heating preparation environment temperature to the set temperature provided in the embodiment of the present application includes: heating the preparation environment temperature to the set temperature, wherein the set temperature range is 20-60° C. As a result, the photoresist layer is warped at the side wall of the stack, so that the photoresist layer is separated from the side wall of the stack to form a gap, and the width d of the gap may be no greater than 1 micron, and this application does not make any specific restrictions on this.

[0074] like Figure 2e As shown, corresponding to step S15 , a transition layer 33 is prepared on the side of the stack away from the substrate 10 , and the transition layer 33 fills the gap d between the sidewall of the stack and the photoresist layer 20 and contacts the substrate 10 .

[0075] In one embodiment of the present application, the transition layer provided in the embodiment of the present application is in contact with the substrate, thereby being able to improve the bonding strength between the electrode and the substrate. The transition layer can be selected from a material with good adhesion to the material of the substrate, such as the adhesion between the material of the transition layer and the material of the substrate is stronger than the adhesion between the material of the conductive layer and the material of the substrate, thereby improving the bonding strength between the electrode and the substrate and improving the problem of the electrode being easy to fall off. Optionally, the material of the transition layer provided in the embodiment of the present application can be the same as the material of the adhesion layer, or the material of the transition layer can be different from the material of the adhesion layer, which needs to be specifically selected according to the actual application.

[0076] like Figure 2f As shown, corresponding to step S16 , a conductive layer 34 is prepared on the side of the transition layer 33 away from the substrate 10 .

[0077] In one embodiment of the present application, the material of the conductive layer provided in the embodiment of the present application is preferably a material with higher conductivity, thereby improving the conductivity of the electrode. Optionally, the conductive layer can be a laminated structure of at least two sublayers, or the conductive layer can also be a separate film layer structure, which is not specifically limited in the present application and needs to be specifically selected according to the actual application. Among them, when the conductive layer includes a laminated structure of at least two sublayers, at least one sublayer can choose a material with low cost and poor conductivity, and at least one sublayer can choose a material with high cost and excellent conductivity. Through the combination of the two types of materials, the conductive layer has the advantages of appropriate cost and excellent conductivity.

[0078] like Figure 2g As shown, corresponding to step S17, the photoresist layer 20 is removed to obtain an electrode, and the electrode includes the adhesion layer 31, the reflective layer 32, the transition layer 33 and the conductive layer 34. Among them, at least one of the adhesion layer 31, the reflective layer 32, the transition layer 33 and the conductive layer 34 provided in the embodiment of the present application is made of metal material or alloy material, and can be prepared by electron beam evaporation process, which is not specifically limited in the present application.

[0079] Based on the same inventive concept, the present application embodiment also provides an electrode structure, which can be specifically combined with Figure 2g As shown, the electrode structure provided in the embodiment of the present application can be applied to an LED chip, wherein the electrode structure includes: a stack located on the surface of one side of the substrate 10 and stacked in sequence, a transition layer 33 and a conductive layer 34, wherein the stack includes an adhesion layer 31 and a reflective layer 32 stacked in sequence, the transition layer 33 extends to cover the side wall of the stack and contacts the surface of the substrate 10, the conductive layer 34 covers at most the surface of the transition layer 33 away from the substrate 10, and the side wall of the transition layer 33 is a curved surface concave toward the stack. It should be noted that the reflective layer 32 provided in the embodiment of the present application can completely cover the exposed surface of the adhesion layer 31 to increase the reflection area, or the reflective layer 32 can also cover at most the surface of the adhesion layer 32 away from the substrate 10, and the present application does not make any specific restrictions on this.

[0080] Based on the same inventive concept, the present application also provides a method for preparing an LED chip. Figure 3 FIG. 1 is a flow chart of a method for preparing an LED chip provided in an embodiment of the present application, wherein the method for preparing an LED chip includes:

[0081] S21. Provide a substrate structure, wherein the substrate structure includes a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current blocking layer and a transparent conductive film layer stacked in sequence.

[0082] S22, preparing a photoresist layer on one side of the transparent conductive film layer of the substrate structure, wherein the photoresist layer includes a first electrode hollowing exposing the transparent conductive film layer.

[0083] S23. Prepare a first electrode on the surface of the transparent conductive film layer in the first electrode hollow, wherein the preparation method of the first electrode comprises: sequentially preparing a first stack of a first adhesion layer and a first reflective layer on the surface of the transparent conductive film layer in the first electrode hollow, the first reflective layer being located on the side of the first adhesion layer away from the transparent conductive film layer; heating the preparation environment temperature to a set temperature so that the photoresist layer is warped at the side wall of the first stack and separated from the side wall of the first stack; preparing a first transition layer on the side of the first stack away from the transparent conductive film layer, the first transition layer filling the gap between the side wall of the first stack and the photoresist layer and contacting the transparent conductive film layer; preparing a first conductive layer on the side of the first transition layer away from the transparent conductive film layer, the first electrode comprises the first adhesion layer, the first reflective layer, the first transition layer and the first conductive layer.

[0084] S24, removing the photoresist layer.

[0085] It can be understood that the technical solution provided in the embodiment of the present application controls the photoresist layer to be lifted by heating the preparation environment temperature, and then extends the prepared first transition layer to fill the gap between the photoresist layer and the side wall of the first stack, and finally makes the first transition layer contact and fix with the transparent conductive film layer, thereby increasing the bonding area and bonding strength between the first electrode and the transparent conductive film layer, and further improving the problem of the first electrode being easy to fall off. In addition, the technical solution provided in the embodiment of the present application only extends the prepared first transition layer to cover the side wall of the first stack, without the need to cover the side wall of the first transition layer with the prepared first conductive layer, thereby reducing the influence of the first electrode on the light brightness, and ensuring the high light brightness of the LED chip.

[0086] Furthermore, the LED chip provided in the embodiment of the present application also includes a second electrode, and the second electrode can also be prepared using the same process as the first electrode preparation method. Specifically, in the LED chip provided by the embodiment of the present application, on the side of the transparent conductive film layer of the substrate structure, the substrate structure includes a step area exposing the first semiconductor layer, and the photoresist layer includes a second electrode hollowing out exposing the first semiconductor layer; the second electrode hollowing out is used to prepare the second electrode on the surface of the first semiconductor layer, wherein the preparation method of the second electrode includes: sequentially preparing a second stack of a second adhesion layer and a second reflective layer on the surface of the first semiconductor layer in the second electrode hollowing out, the second reflective layer being located on the side of the second adhesion layer away from the first semiconductor layer; heating the preparation environment temperature to a set temperature so that the photoresist layer is warped at the side wall of the second stacking layer and separated from the side wall of the second stacking layer; preparing a second transition layer on the side of the second stacking layer away from the first semiconductor layer, the second transition layer filling the gap between the side wall of the second stacking layer and the photoresist layer and contacting the first semiconductor layer; preparing a second conductive layer on the side of the second transition layer away from the first semiconductor layer, the second electrode including the second adhesion layer, the second reflective layer, the second transition layer and the second conductive layer.

[0087] In order to simplify the preparation process and reduce the preparation cost, the second electrode provided in the embodiment of the present application is prepared at the same time as the first electrode and the preparation method is the same. Figure 4 FIG. 1 is a flow chart of another method for preparing an LED chip provided in an embodiment of the present application, wherein the method for preparing an LED chip includes:

[0088] S21. Provide a substrate structure, wherein the substrate structure includes a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current blocking layer and a transparent conductive film layer stacked in sequence, wherein on one side of the transparent conductive film layer of the substrate structure, the substrate structure includes a step area exposing the first semiconductor layer.

[0089] S22, preparing a photoresist layer on one side of the transparent conductive film layer of the substrate structure, wherein the photoresist layer includes a first electrode hollowing that exposes the transparent conductive film layer, and a second electrode hollowing that is included in the step region and exposes the first semiconductor layer.

[0090] S23, preparing a first electrode on the surface of the transparent conductive film layer in the first electrode hollow, and preparing a second electrode on the surface of the first semiconductor layer in the second electrode hollow, wherein the preparation method of the first electrode and the second electrode comprises: sequentially preparing a stack of an adhesion layer and a reflective layer in the first electrode hollow and the second electrode hollow, so as to sequentially prepare a first stack of a first adhesion layer and a first reflective layer on the surface of the transparent conductive film layer in the first electrode hollow, and sequentially prepare a second stack of a second adhesion layer and a second reflective layer on the surface of the first semiconductor layer in the second electrode hollow; heating the preparation environment temperature to a set temperature, so that the photoresist layer is lifted at the side wall of the first stack and separated from the side wall of the first stack, and the photoresist layer is lifted at the side wall of the second stack and separated from the side wall of the second stack; A transition layer is prepared on the bottom side, so as to prepare a first transition layer on the side of the first stack facing away from the transparent conductive film layer, the first transition layer fills the gap between the side wall of the first stack and the photoresist layer and contacts the transparent conductive film layer, and a second transition layer is prepared on the side of the second stack facing away from the first semiconductor layer, the second transition layer fills the gap between the side wall of the second stack and the photoresist layer and contacts the first semiconductor layer; a conductive layer is prepared on the side of the transition layer facing away from the substrate, so as to prepare a first conductive layer on the side of the first transition layer facing away from the transparent conductive film layer, and a second conductive layer is prepared on the side of the second transition layer facing away from the first semiconductor layer, the first electrode includes the first adhesion layer, the first reflective layer, the first transition layer and the first conductive layer; and the second electrode includes the second adhesion layer, the second reflective layer, the second transition layer and the second conductive layer.

[0091] S24, removing the photoresist layer.

[0092] Further integration Figures 5a to 6d The method for preparing the LED chip provided in the embodiment of the present application is described in more detail. Figure 5a to Figure 5d for Figure 4 The corresponding structural diagram of each step in Figures 6a to 6d A schematic structural diagram corresponding to each step of a method for preparing a first electrode and a second electrode provided in an embodiment of the present application.

[0093] like Figure 5a As shown, corresponding to step S21, a substrate structure is provided, wherein the substrate structure includes a substrate 110, a first semiconductor layer 120, an active layer 130, a second semiconductor layer 140, a current blocking layer 150 and a transparent conductive film layer 160 stacked in sequence, wherein on one side of the transparent conductive film layer 160 of the substrate structure, the substrate structure includes a step area exposing the first semiconductor layer 120.

[0094] In one embodiment of the present application, the substrate provided in the embodiment of the present application may be a sapphire substrate, the first semiconductor layer may be an N-type GaN layer, the active layer may be a multi-quantum well layer, and the second semiconductor layer may be a P-type GaN layer, and the present application does not make specific restrictions on this. Among them, the surface of the substrate facing the first semiconductor layer can be microstructured to improve the quality of subsequent epitaxial production and improve the luminous brightness. In addition, the step region provided in the embodiment of the present application can be prepared after the preparation of the second semiconductor layer is completed and before the preparation of the current blocking layer. First, a photoresist mask with a step region pattern is formed on the side of the second semiconductor layer away from the substrate; then an ICP (Inductively Coupled Plasma) etching process is used to remove the second semiconductor layer and the active layer at the step region pattern to obtain a step region of the exposed first semiconductor layer; finally, the photoresist mask is removed.

[0095] The current blocking layer can be formed by depositing on the second semiconductor layer using PECVD (plasma enhanced chemical vapor deposition) equipment, and then etching the initial structure layer of the current blocking layer by photolithography combined with BOE (Buffered Oxide Etch), and finally forming a current blocking layer of a target shape. The material of the current blocking layer can be SiO2, and the thickness of the current blocking layer can range from 2100 to 4100 angstroms. Furthermore, the transparent conductive film layer may be an indium tin oxide (ITO) film layer, and the thickness of the transparent conductive film layer may range from 450 to 900 angstroms; the preparation method of the transparent conductive film layer may be: firstly, a sputtering process is used to form an initial transparent conductive film layer on the side of the current blocking layer away from the substrate, and then the initial transparent conductive film layer is annealed in a rapid annealing furnace, the annealing temperature range may be 500 to 650° C., and the annealing time may be 1 to 10 minutes; then, a positive photoresist is used as a mask to wet-etch the initial transparent conductive film layer, and after etching, the photoresist is removed to obtain a transparent conductive film layer of a target shape covering the current blocking layer.

[0096] like Figure 5b As shown, corresponding to step S22, a photoresist layer 200 is prepared on one side of the transparent conductive film layer 160 of the substrate structure, and the photoresist layer 200 includes a first electrode hollowing out exposing the transparent conductive film layer 160, and a second electrode hollowing out included in the step area and exposing the first semiconductor layer 120.

[0097] like Figure 5cAs shown, corresponding to step S23, a first electrode 301 is prepared on the surface of the transparent conductive film layer 160 in the first electrode hollow, and a second electrode 302 is prepared on the surface of the first semiconductor layer 120 in the second electrode hollow.

[0098] Specific combination Figures 6a to 6d As shown, the method for preparing the first electrode 301 and the second electrode 302 provided in the embodiment of the present application includes: Figure 6a As shown, a stack of adhesion layers and reflective layers is sequentially prepared in the first electrode hollow and the second electrode hollow, so that a first stack of a first adhesion layer 3101 and a first reflective layer 3201 is sequentially prepared in the first electrode hollow on the surface of the transparent conductive film layer 160, and a second stack of a second adhesion layer 3102 and a second reflective layer 3202 is sequentially prepared in the second electrode hollow on the surface of the first semiconductor layer 120; Figure 6b As shown, the preparation environment temperature is heated to a set temperature, so that the photoresist layer 200 is lifted at the side wall of the first stack and separated from the side wall of the first stack, and at the same time, the photoresist layer 200 is lifted at the side wall of the second stack and separated from the side wall of the second stack; as shown Figure 6c As shown, a transition layer is prepared on the side of the stack away from the substrate, so that a first transition layer 3301 is prepared on the side of the first stack away from the transparent conductive film layer 160, the first transition layer 3301 fills the gap between the side wall of the first stack and the photoresist layer 200 and contacts the transparent conductive film layer 160, and a second transition layer 3302 is prepared on the side of the second stack away from the first semiconductor layer 120, the second transition layer 3302 fills the gap between the side wall of the second stack and the photoresist layer 200 and contacts the first semiconductor layer 120; as shown Figure 6d As shown, a conductive layer is prepared on the side of the transition layer facing away from the substrate, so as to prepare a first conductive layer 3401 on the side of the first transition layer 3301 facing away from the transparent conductive film layer 160, and a second conductive layer 3402 is prepared on the side of the second transition layer 3302 facing away from the first semiconductor layer 120, the first electrode includes the first adhesion layer 3101, the first reflective layer 3201, the first transition layer 3301 and the first conductive layer 3401; and the second electrode includes the second adhesion layer 3102, the second reflective layer 3202, the second transition layer 3302 and the second conductive layer 3402.

[0099] The photoresist layer provided in the embodiment of the present application may be a negative photoresist layer, wherein the first stack of a first adhesion layer and a first reflective layer is sequentially prepared on the surface of the transparent conductive film layer in the first electrode hollow, including: preparing a first adhesion layer on the surface of the transparent conductive film layer in the first electrode hollow, preparing a first reflective layer covering the sidewalls of the first adhesion layer and the surface of the side facing away from the transparent conductive film layer. And, the second stack of a second adhesion layer and a second reflective layer is sequentially prepared on the surface of the first semiconductor layer in the second electrode hollow, including: preparing a second adhesion layer on the surface of the first semiconductor layer in the second electrode hollow, preparing a second reflective layer covering the sidewalls of the second adhesion layer and the surface of the side facing away from the first semiconductor layer. Figure 6a As shown, when the photoresist layer is selected to be a negative photoresist layer, when preparing the adhesion layer and the reflective layer, the first reflective layer 3201 can be prepared as a structural layer covering the surface of the first adhesion layer 3101 and its side walls, and the second reflective layer 3202 can be prepared as a structural layer covering the surface of the second adhesion layer 3102 and its side walls, thereby increasing the reflective area of ​​the reflective layer to increase the luminous brightness of the LED chip.

[0100] It should be noted that the photoresist layer provided in the embodiment of the present application can also be a positive photoresist layer, thereby improving the application scope of the electrode preparation method provided in the present application, and the present application does not make any specific restrictions on this.

[0101] At least one of the adhesion layer, reflective layer, transition layer and conductive layer provided in the embodiment of the present application is a metal material or an alloy material, and can be prepared by electron beam evaporation process, and the present application does not make specific restrictions on this. Specifically, the adhesion layer provided in the embodiment of the present application can be prepared by selecting a material with good adhesion to the transparent conductive film layer, such as the adhesion of the material of the first adhesion layer to the transparent conductive film layer is stronger than the adhesion of the material of the first conductive layer to the transparent conductive film layer, thereby improving the bonding strength between the first electrode and the transparent conductive film layer and improving the problem of easy detachment of the electrode. Optionally, the material of the first adhesion layer and the second adhesion layer provided in the embodiment of the present application can be Cr or Ni, and the thickness range of the first adhesion layer and the second adhesion layer is 10-50 angstroms. The first reflective layer and the second reflective layer can be a laminated structure of at least one sublayer, and the sublayer material of the reflective layer can be Al or AlCu alloy, and the thickness range of the first reflective layer and the second reflective layer is 800-1500 angstroms. The first transition layer provided in the embodiment of the present application is in contact with the transparent conductive film layer, and the second transition layer is in contact with the first semiconductor layer, thereby improving the bonding strength between the electrode and its supporting structure. The transition layer can be made of a material with good adhesion, such as the adhesion between the material of the first transition layer and the material of the transparent conductive film layer is stronger than the adhesion between the material of the first conductive layer and the material of the transparent conductive film layer, thereby improving the bonding strength between the first electrode and the transparent conductive film layer and improving the problem of the electrode falling off easily. Optionally, the material of the transition layer provided in the embodiment of the present application can be the same as the material of the adhesion layer, or the material of the transition layer can be different from the material of the adhesion layer, which needs to be specifically selected according to the actual application. Among them, the material of the first transition layer and the second transition layer can be Cr or Ti, and the thickness range of the first transition layer and the second transition layer is 300-1500 angstroms.

[0102] And, the material of the conductive layer provided in the embodiment of the present application is preferably a material with higher conductivity, thereby improving the conductivity of the electrode. Optionally, the conductive layer (the first conductive layer and the second conductive layer) can be a laminated structure of at least two sublayers, or the conductive layer can also be a separate film layer structure, which is not specifically limited in this application and needs to be specifically selected according to the actual application. Among them, when the conductive layer includes a laminated structure of at least two sublayers, at least one sublayer can choose a material with low cost and poor conductivity, and at least one sublayer can choose a material with high cost and excellent conductivity. Through the combination of the two types of materials, the conductive layer has the advantages of appropriate cost and excellent conductivity. Optionally, the conductive layer includes a first sublayer of Ti / Pt (a laminate of a Ti layer and a Pt layer) or Ni / Pt (a laminate of a Ni layer and a Pt layer), and the thickness range of the first sublayer can be 2000-6000 angstroms, and a second sublayer of Cu, Au or Au / Ti (a laminate of an Au layer and a Ti layer) prepared later, and the thickness range of the second sublayer can be 10000-20000 angstroms.

[0103] In one embodiment of the present application, the heating of the preparation environment temperature to the set temperature provided in the embodiment of the present application includes: heating the preparation environment temperature to the set temperature, wherein the set temperature range is 20-60° C. As a result, the photoresist layer is warped at the side wall of the stack, so that the photoresist layer is separated from the side wall of the stack to form a gap, and the width of the gap may be no greater than 1 micron, and this application does not make any specific restrictions on this.

[0104] like Figure 5d As shown, corresponding to step S24, the photoresist layer is removed. Further, a PECVD device is used to deposit an insulating layer 400 on the electrode side to cover the exposed surfaces of the transparent conductive layer 160, the first electrode 301, the first semiconductor layer 120, and the second electrode 302 for protection, and a positive photoresist is used as a mask to wet-etch the insulating layer 400 to expose the external surfaces of the first electrode 301 and the second electrode 302 to obtain an insulating layer 400 of a target shape. The insulating layer 400 may be made of SiO2, and the thickness of the insulating layer 400 may range from 2300 to 10000 angstroms.

[0105] Furthermore, after the preparation of the above structure is completed, it is necessary to perform push-pull force tests, electrical performance tests, etc. on the prepared structure; after the above structure is tested, the substrate is thinned to a set thickness, such as a thickness range of 100-102 microns; then a distributed Bragg reflector (DBR) layer is evaporated on the side of the substrate away from the first semiconductor layer, and its thickness can be 3-5 microns; finally, the processes of splitting, testing and sorting are performed, which are the same as the prior art, so no unnecessary details are given.

[0106] Based on the same inventive concept, the present application embodiment also provides an LED chip. Figure 7 FIG. 1 is a schematic diagram of the structure of an LED chip provided in an embodiment of the present application, wherein the LED chip provided in an embodiment of the present application includes:

[0107] A substrate structure, the substrate structure includes a substrate 110, a first semiconductor layer 120, an active layer 130, a second semiconductor layer 140, a current blocking layer 150 and a transparent conductive film layer 160 stacked in sequence; a first electrode 301 located on the side of the transparent conductive film layer 160 away from the substrate 110, the first electrode 301 includes a first stack, a first transition layer 3301 and a first conductive layer 3401 stacked in sequence, wherein the first stack includes a first adhesion layer 3101 and a first reflective layer 3201 stacked in sequence, the first transition layer 3301 extends to cover the side wall of the first stack and contacts with the transparent conductive film layer 160, the first conductive layer 3401 covers at most the surface of the first transition layer 3301 on the side away from the substrate 110, and the side wall of the first transition layer 3301 is an arc surface concave toward the first stack.

[0108] Continue to refer Figure 7 As shown, on one side of the transparent conductive film layer 160 of the substrate structure, the substrate structure includes a step region exposing the first semiconductor layer 120, and the LED chip includes: a second electrode 302 located at the step region and on the surface of the first semiconductor layer 120, the second electrode 302 includes a second stack, a second transition layer 3302 and a second conductive layer 3402 stacked in sequence, wherein the second stack includes a second adhesion layer 3102 and a second reflective layer 3202 stacked in sequence, the second transition layer 3302 extends to cover the side wall of the second stack and contacts the first semiconductor layer 120, the second conductive layer 3402 covers at most the surface of the second transition layer 3302 facing away from the substrate 110, and the side wall of the second transition layer 3302 is an arc surface concave toward the second stack. It can be understood that when the LED chip provided in the embodiment of the present application is prepared by the preparation method of the LED chip provided in any of the above embodiments, since the transition layer is filled after the photoresist layer is lifted, the side wall of the transition layer is a slightly arc surface structure concave toward the inside.

[0109] Furthermore, the LED chip provided in the embodiment of the present application also includes an insulating layer on the electrode side and used for the LED chip, a distributed Bragg reflector layer located on the side of the substrate away from the first semiconductor layer, and other optimized structures (not shown), etc., which are not specifically limited in the present application. Also, the thickness of the first adhesion layer and the second adhesion layer provided in the embodiment of the present application is in the range of 10-50 angstroms; the thickness of the first reflection layer and the second reflection layer is in the range of 800-1500 angstroms; and the thickness of the first transition layer and the second transition layer is in the range of 300-1500 angstroms, which are not specifically limited in the present application.

[0110] The embodiments of the present application provide an electrode preparation method, an electrode structure, an LED chip and a preparation method thereof, wherein the electrode preparation method comprises: providing a substrate; preparing a photoresist layer on the surface of the substrate, the photoresist layer comprising an electrode hollow; sequentially preparing a stack of an adhesion layer and a reflective layer in the electrode hollow on the surface of the substrate, the reflective layer being located on the side of the adhesion layer away from the substrate; heating the preparation environment temperature to a set temperature so that the photoresist layer is warped at the side wall of the stack and separated from the side wall of the stack; preparing a transition layer on the side of the stack away from the substrate, the transition layer filling the gap between the side wall of the stack and the photoresist layer and contacting the substrate; preparing a conductive layer on the side of the transition layer away from the substrate; removing the photoresist layer to obtain an electrode, the electrode comprising the adhesion layer, the reflective layer, the transition layer and the conductive layer.

[0111] Furthermore, the preparation method of the first electrode provided in the embodiment of the present application includes: sequentially preparing a first stack of a first adhesion layer and a first reflective layer on the surface of the transparent conductive film layer in the hollow of the first electrode, the first reflective layer being located on the side of the first adhesion layer away from the transparent conductive film layer; heating the preparation environment temperature to a set temperature so that the photoresist layer is warped at the side wall of the first stack and separated from the side wall of the first stack; preparing a first transition layer on the side of the first stack away from the transparent conductive film layer, the first transition layer fills the gap between the side wall of the first stack and the photoresist layer and contacts the transparent conductive film layer; preparing a first conductive layer on the side of the first transition layer away from the transparent conductive film layer, the first electrode includes the first adhesion layer, the first reflective layer, the first transition layer and the first conductive layer.

[0112] From the above content, it can be known that the technical solution provided by the embodiment of the present application controls the photoresist layer to be lifted by heating the preparation environment temperature, and then extends the corresponding transition layer to fill the gap between the photoresist layer and the side wall of the stack, and finally makes the transition layer contact and fix with the corresponding substrate, and makes the transition layer contact and fix with the corresponding transparent conductive film layer, thereby increasing the bonding area and bonding strength between the electrode and its supporting structure, and then improving the problem of easy detachment of the electrode. In addition, the technical solution provided by the embodiment of the present application only extends the prepared first transition layer to cover the side wall of the first stack, without the need to cover the side wall of the first transition layer with the prepared first conductive layer, which reduces the influence of the first electrode on the light brightness, and ensures that the light brightness of the LED chip is high.

[0113] In the description of the embodiments of the present application, it needs to be understood that the orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0114] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0115] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0116] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0117] In the embodiments of the present application, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradicting each other.

[0118] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for preparing an electrode, characterized in that: The preparation method comprises: providing a substrate; Preparing a photoresist layer on the surface of the substrate, wherein the photoresist layer includes an electrode hollowing; An adhesion layer and a reflection layer are sequentially prepared in the electrode hollowing and stacked on the surface of the substrate, wherein the reflection layer is located on a side of the adhesion layer away from the substrate; Heating the preparation environment temperature to a set temperature so that the photoresist layer is lifted at the side wall of the stack and separated from the side wall of the stack; A transition layer is prepared on a side of the stack away from the substrate, wherein the transition layer fills a gap between the sidewall of the stack and the photoresist layer and contacts the substrate; Preparing a conductive layer on the side of the transition layer away from the substrate; The photoresist layer is removed to obtain an electrode, wherein the electrode includes the adhesion layer, the reflective layer, the transition layer and the conductive layer.

2. The method for preparing an electrode according to claim 1, characterized in that: The photoresist layer is a negative photoresist layer, wherein the stacking of the adhesion layer and the reflective layer is sequentially prepared in the electrode hollowing on the surface of the substrate, comprising: preparing an adhesion layer in the electrode hollowing out on the surface of the substrate, A reflective layer is prepared to cover the sidewall of the adhesion layer and the surface of the side facing away from the substrate.

3. An electrode structure, applied to an LED chip, characterized in that: The electrode structure comprises: A stack, a transition layer and a conductive layer are sequentially stacked on one side surface of a substrate, wherein the stack comprises an adhesion layer and a reflective layer sequentially stacked, the transition layer extends to cover the side wall of the stack and contacts the surface of the substrate, the conductive layer at most covers the surface of the transition layer facing away from the substrate, and the side wall of the transition layer is a curved surface concave toward the stack.

4. A method for preparing an LED chip, characterized in that: The preparation method comprises: Providing a substrate structure, the substrate structure comprising a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current blocking layer and a transparent conductive film layer stacked in sequence; Preparing a photoresist layer on one side of the transparent conductive film layer of the substrate structure, wherein the photoresist layer includes a first electrode hollowing exposing the transparent conductive film layer; A first electrode is prepared on the surface of the transparent conductive film layer in the first electrode hollowing, wherein the preparation method of the first electrode comprises: preparing a first stack of a first adhesion layer and a first reflective layer in sequence on the surface of the transparent conductive film layer in the first electrode hollowing, wherein the first reflective layer is located on the side of the first adhesion layer away from the transparent conductive film layer; heating the preparation environment temperature to a set temperature, so that the photoresist layer is peeled off at the side wall of the first stack and separated from the side wall of the first stack; preparing a first transition layer on the side of the first stack away from the transparent conductive film layer, wherein the first transition layer fills the gap between the side wall of the first stack and the photoresist layer and contacts the transparent conductive film layer; preparing a first conductive layer on the side of the first transition layer away from the transparent conductive film layer, wherein the first electrode comprises the first adhesion layer, the first reflective layer, the first transition layer and the first conductive layer; The photoresist layer is removed.

5. The method for preparing an LED chip according to claim 4, characterized in that: On one side of the transparent conductive film layer of the substrate structure, the substrate structure includes a step region exposing the first semiconductor layer, and the photoresist layer includes a second electrode hollow exposing the first semiconductor layer; The second electrode hollowing is used to prepare the second electrode on the surface of the first semiconductor layer, wherein the preparation method of the second electrode includes: sequentially preparing a second stack of a second adhesion layer and a second reflective layer on the surface of the first semiconductor layer in the second electrode hollowing, the second reflective layer being located on the side of the second adhesion layer away from the first semiconductor layer; heating the preparation environment temperature to a set temperature so that the photoresist layer is peeled off at the side wall of the second stacking layer and separated from the side wall of the second stacking layer; preparing a second transition layer on the side of the second stacking layer away from the first semiconductor layer, the second transition layer fills the gap between the side wall of the second stacking layer and the photoresist layer and contacts the first semiconductor layer; preparing a second conductive layer on the side of the second transition layer away from the first semiconductor layer, the second electrode includes the second adhesion layer, the second reflective layer, the second transition layer and the second conductive layer.

6. The method for preparing an LED chip according to claim 5, characterized in that: The second electrode is prepared simultaneously with the first electrode using the same preparation method.

7. The method for preparing an LED chip according to claim 5, characterized in that: The photoresist layer is a negative photoresist layer, wherein the first stack of a first adhesion layer and a first reflective layer is sequentially prepared in the first electrode hollow on the surface of the transparent conductive film layer, including: A first adhesion layer is prepared in the first electrode hollow on the surface of the transparent conductive film layer, Prepare a first reflective layer covering the sidewall of the first adhesion layer and the surface of the side facing away from the transparent conductive film layer; And, the second stack of a second adhesion layer and a second reflective layer is sequentially prepared in the second electrode hollow on the surface of the first semiconductor layer, including: A second adhesion layer is prepared in the second electrode hollow on the surface of the first semiconductor layer, A second reflective layer is prepared to cover the sidewall of the second adhesion layer and a surface of the side facing away from the first semiconductor layer.

8. The method for preparing an LED chip according to claim 1, characterized in that: The step of heating the preparation environment temperature to a set temperature comprises: The preparation environment temperature is heated to a set temperature, wherein the set temperature range is 20-60°C.

9. An LED chip, characterized in that: The LED chip comprises: A substrate structure, the substrate structure comprising a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current blocking layer and a transparent conductive film layer stacked in sequence; A first electrode is located on the side of the transparent conductive film layer facing away from the substrate, the first electrode includes a first stack, a first transition layer and a first conductive layer stacked in sequence, wherein the first stack includes a first adhesion layer and a first reflective layer stacked in sequence, the first transition layer extends to cover the side wall of the first stack and contacts the transparent conductive film layer, the first conductive layer covers at most the surface of the first transition layer on the side facing away from the substrate, and the side wall of the first transition layer is a curved surface concave toward the first stack.

10. The LED chip according to claim 9, characterized in that: On one side of the transparent conductive film layer of the substrate structure, the substrate structure includes a step region exposing the first semiconductor layer, and the LED chip includes: A second electrode is located at the step region and on the surface of the first semiconductor layer, the second electrode includes a second stack, a second transition layer and a second conductive layer stacked in sequence, wherein the second stack includes a second adhesion layer and a second reflective layer stacked in sequence, the second transition layer extends to cover the side wall of the second stack and contacts the first semiconductor layer, the second conductive layer covers at most the surface of the second transition layer on the side facing away from the substrate, and the side wall of the second transition layer is a curved surface concave toward the second stack.

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