Light Emitting Diode and its Fabrication Method

Abstract

This disclosure provides a light-emitting diode (LED) and a method for fabricating an LED. The LED includes an epitaxial structure, a reflective layer, and an electrode structure. The electrode structure includes a first electrode, a first electrode pad, a second electrode, and a second electrode pad. The first electrode pad penetrates the reflective layer and is connected to the first electrode, and the second electrode pad penetrates the reflective layer and is connected to the second electrode. Both the first and second electrode pads include a first adhesion metal layer, a flexible metal layer, a protective metal layer, a second adhesion metal layer, a reactive metal layer, and a conductive metal layer, which are sequentially stacked.

Description

Technical Field

[0001] This disclosure relates to the field of light-emitting devices, and in particular to a light-emitting diode and a method for fabricating a light-emitting diode. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor device that emits light. Due to its advantages such as energy saving, high brightness, high durability, long life and light weight, it has been widely used in the display and lighting markets.

[0003] The related technology provides a light-emitting diode, the structure of which includes a substrate, an epitaxial structure, a reflective layer and an electrode structure. The electrode structure includes electrode pads, and the quality of the electrode pads directly affects the reliability of the LED.

[0004] When electrode pads are fabricated using traditional processes, the internal structure of the electrode pads of the light-emitting diode (LED) is prone to breakage under external force, causing the LED chip to detach from the bracket and resulting in LED failure. Summary of the Invention

[0005] This disclosure provides a light-emitting diode (LED) and a method for manufacturing the LED, which improves the flexibility of the chip electrode pads, thereby mitigating the chip detachment problem caused by internal fracture of the electrode pads during flexible LED strip applications. The technical solution is as follows:

[0006] On the one hand, a light-emitting diode is provided, the light-emitting diode comprising: an epitaxial structure, a reflective layer, and an electrode structure;

[0007] The epitaxial structure includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked sequentially, wherein the first semiconductor layer, the active layer, and the second semiconductor layer form a stepped structure; the reflective layer covers the surface of the stepped structure; and the electrode structure includes a first electrode and a first electrode pad, a second electrode, and a second electrode pad.

[0008] Both the first electrode pad and the second electrode pad include a first adhesive metal layer, a flexible metal layer, a protective metal layer, a second adhesive metal layer, a reactive metal layer, and a conductive metal layer stacked sequentially.

[0009] Optionally, the flexible metal layer is an Ag layer, a Cu layer, or a Sn layer.

[0010] Optionally, the flexible metal layer is an Ag layer.

[0011] Optionally, the thickness of the flexible metal layer is 5000 to 20000 angstroms.

[0012] Optionally, the first adhesion metal layer is a TiW layer, the protective metal layer is a Ni layer, the second adhesion metal layer is a TiW layer, the reactive metal layer is a Ni layer, and the conductive metal layer is an Au layer.

[0013] Optionally, the thickness of the first adhesive metal layer is 5 to 1000 angstroms, the thickness of the protective metal layer is 1000 to 3000 angstroms, the thickness of the second adhesive metal layer is 500 to 2000 angstroms, the thickness of the reactive metal layer is 5000 to 10000 angstroms, and the thickness of the conductive metal layer is 500 to 2000 angstroms.

[0014] On the other hand, a method for fabricating a light-emitting diode includes:

[0015] A first semiconductor layer, an active layer, and a second semiconductor layer are fabricated in sequence, and the first semiconductor layer, the active layer, and the second semiconductor layer constitute an epitaxial structure.

[0016] The extensional structure is graphically processed to form a stepped structure;

[0017] A reflective layer is fabricated on the epitaxial structure, the reflective layer covering the stepped structure;

[0018] An electrode structure is fabricated that connects the reflective layer to the epitaxial structure. The electrode structure includes a first electrode, a first electrode pad, a second electrode, and a second electrode pad. The first electrode is located on a stepped surface, and the second electrode is located on the surface of a transparent conductive layer. The first electrode pad penetrates the reflective layer and is connected to the first electrode, and the second electrode pad penetrates the reflective layer and is connected to the second electrode. The first electrode pad and the second electrode pad include a first adhesion metal layer, a flexible metal layer, a protective metal layer, a second adhesion metal layer, a reactive metal layer, and a conductive metal layer stacked sequentially.

[0019] Optionally, the fabrication of the electrode structure connecting the reflective layer and the epitaxial structure includes:

[0020] Before fabricating the reflective layer, the first electrode and the second electrode are fabricated, with the first electrode located on the stepped surface and the second electrode located on the surface of the transparent conductive layer.

[0021] After the reflective layer is fabricated, it is patterned to form a first through-hole and a second through-hole.

[0022] The first electrode pad and the second electrode pad are fabricated. The first electrode pad is connected to the first electrode through the first through hole, and the second electrode pad is connected to the second electrode through the second through hole.

[0023] Optionally, the fabrication of the first electrode pad and the second electrode pad includes:

[0024] At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The first adhesion metal layer with a thickness of 5 to 1000 angstroms is grown under the conditions of pa and a evaporation rate of 1 to 3 angstroms / s.

[0025] At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The flexible metal layer with a thickness of 5,000 to 20,000 angstroms is grown under conditions of pa and a evaporation rate of 7 to 9 angstroms / s.

[0026] At a temperature of 70–80℃ and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The protective metal layer with a thickness of 1000-3000 angstroms is grown under the conditions of pa and a evaporation rate of 2-4 angstroms / s.

[0027] At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 A second adhesion metal layer with a thickness of 500 to 2000 angstroms is grown under conditions of pa and a evaporation rate of 1 to 3 angstroms / s.

[0028] At a temperature of 70–80℃ and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The reactive metal layer with a thickness of 5000-10000 angstroms is grown under conditions of pa and a evaporation rate of 4-6 angstroms / s.

[0029] At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The conductive metal layer with a thickness of 500 to 2000 angstroms is grown under conditions of pa and a vapor deposition rate of 1 to 3 angstroms / s.

[0030] Optionally, the flexible metal layer is an Ag layer, a Cu layer, or a Sn layer.

[0031] The beneficial effects of the technical solutions provided in this disclosure are:

[0032] In this embodiment, the first and second electrode pads in the light-emitting diode each comprise a first adhesive metal layer, a flexible metal layer, a protective metal layer, a second adhesive metal layer, a reactive metal layer, and a conductive metal layer, stacked sequentially. The first and second adhesive metal layers improve adhesion between the various film layers within the pad and enhance adhesion between the pad and the reflective layer, preventing detachment of the electrode pad from the reflective layer. The flexible metal layer exhibits high plasticity and elasticity; it deforms under external force and returns to its original state after the force is removed. It also possesses excellent electrical and thermal conductivity. The protective metal layer provides excellent oxidation resistance, effectively protecting the flexible metal layer. The reactive metal layer reacts with the solder paste and support used for packaging, enhancing soldering and packaging performance. The conductive metal layer facilitates testing of the chip's photoelectric parameters. Using these six metal layers to form the electrode pad effectively improves the flexibility of the chip electrode pad, thereby mitigating the chip detachment problem caused by internal breakage of the electrode pad during flexible LED strip applications. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure;

[0035] Figure 2 This is a schematic diagram of the structure of a reflective layer provided in an embodiment of this disclosure;

[0036] Figure 3 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure;

[0037] Figure 4 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure embodiment;

[0038] Figure 5 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0039] Figure 6 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0040] Figure 7 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0041] Figure 8 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in the embodiments of this disclosure.

[0042] The attached figures are labeled as follows:

[0043] 10: Electrode structure; 100: Substrate; 101: First semiconductor layer; 102: Active layer; 103: Second semiconductor layer; 104: Transparent conductive layer; 105: First electrode; 106: Second electrode; 107: Reflective layer; 108: First electrode pad; 109: Second electrode pad; 110: First via; 111: Second via; 120: Step surface of stepped structure; 1000: Epitaxial structure; 201: First adhesion metal layer; 202: Flexible metal layer; 203: Protective metal layer; 204: Second adhesion metal layer; 205: Reactive metal layer; 206: Conductive metal layer; 200: Step structure. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 1 The light-emitting diode includes: an epitaxial structure 1000, a reflective layer 107, and an electrode structure 10.

[0046] In this embodiment, the epitaxial structure 1000 includes a first semiconductor layer 101, an active layer 102, and a second semiconductor layer 103 stacked sequentially, forming a stepped structure 200. A reflective layer 107 covers the surface of the stepped structure 200. The electrode structure 10 includes a first electrode 105, a first electrode pad 108, a second electrode 106, and a second electrode pad 109. The first electrode 105 is located on the stepped surface 120, and the second electrode 106 is located on the surface of the second semiconductor layer 103. The first electrode pad 108 penetrates the reflective layer 107 and is connected to the first electrode 105, and the second electrode pad 109 penetrates the reflective layer 107 and is connected to the second electrode 106.

[0047] Figure 2 This is a schematic diagram of the structure of an electrode pad provided in an embodiment of this disclosure. Figure 2 As shown, the first electrode pad 108 and the second electrode pad 109 both include a first adhesion metal layer 201, a flexible metal layer 202, a protective metal layer 203, a second adhesion metal layer 204, a reactive metal layer 205 and a conductive metal layer 206 stacked sequentially.

[0048] In this embodiment, the first electrode pad 108 and the second electrode pad 109 in the light-emitting diode each include a first adhesion metal layer 201, a flexible metal layer 202, a protective metal layer 203, a second adhesion metal layer 204, a reactive metal layer 205, and a conductive metal layer 206 stacked sequentially. The first and second adhesion metal layers improve the adhesion between the various film layers within the pad and enhance the adhesion between the pad and the reflective layer, preventing the electrode pad from detaching from the contact surface of the reflective layer. The flexible metal layer is highly malleable and elastic; it deforms under external force and returns to its original state after the force is removed. It also possesses excellent electrical and thermal conductivity. The protective metal layer exhibits good oxidation resistance, effectively protecting the flexible metal layer. The reactive metal layer reacts and bonds with the solder paste and support used for packaging, improving the soldering and packaging effect. The conductive metal layer facilitates the testing of the chip's photoelectric parameters. The electrode pads composed of the above-mentioned 6-layer metal stack effectively improve the flexibility of the chip electrode pads, thereby improving the chip detachment problem caused by internal fracture of the electrode pads during the application of flexible LED strips.

[0049] In this embodiment, the first adhesive metal layer 201 can be a TiW layer. The TiW layer has good adhesion to the reflective layer and stronger adhesion, preventing the electrode pads from falling off at the contact surface with the reflective layer.

[0050] In this embodiment of the disclosure, the thickness of the first adhesive metal layer 201 can be 5 to 1000 angstroms.

[0051] For example, the thickness of the first adhesive metal layer 201 is 500 angstroms.

[0052] In this implementation, the adhesion layer of the above thickness is used, which on the one hand can satisfy the adhesion effect between the reflective layer and the electrode pad, and on the other hand, the thickness will not cause the thickness of the entire light-emitting diode to be too large.

[0053] In this embodiment of the disclosure, the flexible metal layer 202 may be an Ag layer, a Cu layer, or a Sn layer.

[0054] For example, the flexible metal layer 202 is an Ag layer. The Ag layer has high plasticity and good elasticity, which allows the Ag layer to deform under the action of external force and return to its original state after the external force is removed. At the same time, the Ag flexible metal layer also has excellent electrical and thermal conductivity.

[0055] In this embodiment of the disclosure, the thickness of the flexible metal layer 202 can be 5000 to 20000 angstroms.

[0056] For example, the flexible metal layer 202 has a thickness of 15,000 angstroms.

[0057] In this implementation, the use of a flexible metal layer of the aforementioned thickness satisfies both the plasticity and good elasticity of the flexible metal layer, while also ensuring its excellent electrical and thermal conductivity.

[0058] In this embodiment, the protective metal layer 203 can be a Ni layer, which has excellent oxidation resistance and can effectively protect the flexible metal layer.

[0059] In this embodiment, the thickness of the protective metal layer 203 can be 1000 to 3000 angstroms.

[0060] For example, the protective metal layer 203 has a thickness of 2000 angstroms.

[0061] In this implementation, the protective metal layer of the aforementioned thickness can effectively protect the flexible metal layer while ensuring that the overall thickness of the light-emitting diode is not excessive.

[0062] In this embodiment, the second adhesive metal layer 204 can be a TiW layer, which has good adhesion and stronger adhesion.

[0063] In this embodiment of the disclosure, the thickness of the second adhesive metal layer 204 can be 500 to 2000 angstroms.

[0064] For example, the second adhesive metal layer 204 has a thickness of 1500 angstroms.

[0065] In this implementation, the second adhesion layer of the aforementioned thickness can satisfy the adhesion effect between the reactive metal layer and the electrode pads, while ensuring that the thickness does not result in an excessively large overall thickness of the light-emitting diode.

[0066] In this embodiment, the reactive metal layer 205 can be a Ni layer, which can react with solder paste to achieve a die-bonding effect, fixing the electrode pads to the substrate. The solder paste is placed between the substrate and the chip, and after high-temperature reflow soldering, a die-bonding effect is achieved. The reflow soldering process first raises the temperature to a high temperature, at which point the solder paste melts into a liquid, which can bond with the metal on the substrate and simultaneously with the reactive metal layer in the chip pads. Then, the temperature is gradually lowered, and during the cooling process, the solder paste gradually solidifies, achieving the effect of soldering the chip to the substrate.

[0067] In this embodiment, the thickness of the reactive metal layer 205 can be 5000 to 10000 angstroms.

[0068] For example, the reactive metal layer 205 has a thickness of 7000 angstroms.

[0069] In this implementation, the use of the aforementioned thickness of the reactive metal layer ensures that the reactive metal layer can fully react with the solder paste to achieve the effect of die bonding and fix the electrode pads on the support. On the other hand, this thickness does not result in an excessively large thickness of the entire light-emitting diode.

[0070] In this embodiment, the conductive metal layer 206 can be an Au layer, which has good conductivity and facilitates the testing of photoelectric parameters of the chip.

[0071] In this embodiment of the disclosure, the thickness of the conductive metal layer 206 can be 500 to 2000 angstroms.

[0072] For example, the conductive metal layer 206 has a thickness of 1500 angstroms.

[0073] In this implementation, using a conductive metal layer of the aforementioned thickness ensures good conductivity of the conductive metal layer while preventing the overall thickness of the light-emitting diode from becoming too large.

[0074] In this embodiment of the disclosure, the epitaxial structure 1000 is located on the substrate 100.

[0075] The substrate 100 can be any one of sapphire substrate, Si substrate, SiC substrate, etc., and this disclosure does not limit the material of the substrate.

[0076] For example, substrate 100 is a sapphire substrate.

[0077] In this embodiment of the disclosure, the first semiconductor layer 101 can be an N-type semiconductor layer, and the second semiconductor layer 103 can be a P-type semiconductor layer.

[0078] For example, the first semiconductor layer 101 can be an N-type GaN layer, and the second semiconductor layer 103 can be a P-type GaN layer.

[0079] Accordingly, the first electrode can be an N-electrode, and the first electrode pad can be an N-electrode pad; the second electrode can be a P-electrode, and the second electrode pad can be a P-electrode pad.

[0080] In another example, the first semiconductor layer 101 can be a P-type semiconductor layer, and the second semiconductor layer 103 can be an N-type semiconductor layer.

[0081] In another example, the first electrode can be a P electrode and the first electrode pad can be a P electrode pad; the second electrode can be an N electrode and the second electrode pad can be an N electrode pad.

[0082] In this embodiment of the disclosure, the active layer 102 can be a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0083] In this embodiment of the disclosure, the reflective layer 107 is a distributed Bragg reflector (DBR) layer, such as a DBR composed of SiO2 and Ti2O3.

[0084] Optionally, the light-emitting diode may further include a transparent conductive layer 104, wherein the second electrode 106 on the epitaxial structure 1000 is connected to the transparent conductive layer 104.

[0085] In this embodiment of the disclosure, the transparent conductive layer 104 can be an indium tin oxide (ITO) layer. ITO has excellent transparency and conductivity, allowing light to pass through while also conducting current to form an electrical connection.

[0086] It is worth noting that, in the embodiments of this disclosure, the structure can be selectively added or reduced based on the structure of the light-emitting diode described above, and this disclosure does not limit this.

[0087] Figure 3 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 3 The method includes the following steps:

[0088] S11. Fabricate a first semiconductor layer, an active layer, and a second semiconductor layer stacked sequentially, the first semiconductor layer, the active layer, and the second semiconductor layer constituting an epitaxial structure.

[0089] S12. The extensional structure is graphically processed to form a stepped structure.

[0090] S13. A reflective layer is fabricated on the epitaxial structure, and the reflective layer covers the stepped structure.

[0091] S14. Fabricate an electrode structure that penetrates the reflective layer and connects to the epitaxial structure. The electrode structure includes a first electrode, a first electrode pad, a second electrode, and a second electrode pad. The first electrode is located on a step surface, and the second electrode is located on the surface of the second semiconductor layer. The first electrode pad penetrates the reflective layer and is connected to the first electrode, and the second electrode pad penetrates the reflective layer and is connected to the second electrode. The first electrode pad and the second electrode pad include a first adhesion metal layer, a flexible metal layer, a protective metal layer, a second adhesion metal layer, a reactive metal layer, and a conductive metal layer stacked sequentially.

[0092] In this embodiment, the first and second electrode pads in the light-emitting diode each comprise a first adhesive metal layer, a flexible metal layer, a protective metal layer, a second adhesive metal layer, a reactive metal layer, and a conductive metal layer, stacked sequentially. The first and second adhesive metal layers improve adhesion between the various film layers within the pad and enhance adhesion between the pad and the reflective layer, preventing detachment of the electrode pad from the reflective layer. The flexible metal layer exhibits high plasticity and elasticity; it deforms under external force and returns to its original state after the force is removed. It also possesses excellent electrical and thermal conductivity. The protective metal layer provides excellent oxidation resistance, effectively protecting the flexible metal layer. The reactive metal layer reacts with the solder paste and support used for packaging, enhancing soldering and packaging performance. The conductive metal layer facilitates testing of the chip's photoelectric parameters. Using these six metal layers to form the electrode pad effectively improves the flexibility of the chip electrode pad, thereby mitigating the chip detachment problem caused by internal breakage of the electrode pad during flexible LED strip applications.

[0093] Figure 4 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure. See also... Figure 4 The method includes the following steps:

[0094] S21. A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially formed on a substrate, wherein the first semiconductor layer, the active layer, and the second semiconductor layer constitute an epitaxial structure.

[0095] In one example, step S21 includes:

[0096] The first step is to fabricate the first semiconductor layer.

[0097] In this embodiment of the disclosure, the first semiconductor layer is an N-type GaN layer.

[0098] The second step is to create the active layer.

[0099] In this embodiment of the disclosure, the active layer is a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0100] The third step is to fabricate the second semiconductor layer.

[0101] In this embodiment of the disclosure, the second semiconductor layer is a P-type GaN layer.

[0102] In the embodiments disclosed herein, the substrate can be any one of a sapphire substrate, a Si substrate, etc., for example, a sapphire substrate.

[0103] For example, the first semiconductor layer, the active layer, and the second semiconductor layer are fabricated using a metal-organic chemical vapor deposition (MOCVD) apparatus.

[0104] S22. Graphicalize the extensional structure to form a stepped structure.

[0105] In this embodiment of the disclosure, inductively coupled plasma (ICP) dry etching technology is used to pattern the sequentially stacked first semiconductor layer, active layer, and second semiconductor layer to form a stepped structure.

[0106] In this embodiment of the disclosure, the stepped surface of the stepped structure is located in the first semiconductor layer.

[0107] Figure 5 This is a schematic diagram of the structure during the fabrication process of the light-emitting diode provided in the embodiments of this disclosure, as shown below. Figure 5 As shown, a first semiconductor layer 101, an active layer 102, and a second semiconductor layer 103 are sequentially grown on a substrate 100, and a step structure 200 extending from the second semiconductor layer 103 to the first semiconductor layer 101 is formed on the second semiconductor layer 103.

[0108] S23. Fabricate a transparent conductive layer on the epitaxial structure.

[0109] In this embodiment, the transparent conductive layer can be an ITO layer. ITO has excellent transparency and conductivity, allowing light to pass through while also conducting current to form an electrical connection.

[0110] In one example, step S23 includes:

[0111] The first step is to deposit an ITO thin film.

[0112] The second step involves patterning the ITO thin film using photolithography and etching techniques to obtain a transparent conductive layer.

[0113] Figure 6 This is a schematic diagram of the structure during the fabrication process of the light-emitting diode provided in the embodiments of this disclosure, as shown below. Figure 6 As shown, a transparent conductive layer 104 is fabricated on the epitaxial structure 1000, and the transparent conductive layer 104 is located on the surface of the second semiconductor layer 103 of the epitaxial structure 1000.

[0114] S24. Fabricate a first electrode and a second electrode, with the first electrode located on the stepped surface and the second electrode located on the surface of the transparent conductive layer.

[0115] In one example, step S24 includes:

[0116] A first electrode is formed on the step surface of the first semiconductor layer and a second electrode is formed on the surface of the transparent conductive layer using electron beam evaporation or magnetron sputtering technology.

[0117] Figure 7 This is a schematic diagram of the structure during the fabrication process of the light-emitting diode provided in the embodiments of this disclosure, as shown below. Figure 7 As shown, the first electrode 105 is located on the stepped surface 120, and the second electrode 106 is located on the surface of the transparent conductive layer 104.

[0118] S25. Fabricate a reflective layer, which covers the stepped structure, the transparent conductive layer, the first electrode, and the second electrode.

[0119] In this embodiment of the disclosure, a DBR layer is fabricated on the surface of the second semiconductor layer and the stepped structure using physical vapor deposition (PVD) technology to form a reflective layer.

[0120] S26. The reflective layer is patterned to form the first through hole and the second through hole.

[0121] In this embodiment of the disclosure, after a pattern is formed on the surface using photolithography, an ICP etching process is used to etch the target pattern. The first through-hole penetrates the reflective layer and is connected to the first electrode, and the second through-hole penetrates the reflective layer and is connected to the second electrode.

[0122] Figure 8 This is a schematic diagram of the structure during the fabrication process of the light-emitting diode provided in the embodiments of this disclosure, as shown below. Figure 8 As shown, the reflective layer 107 covers the stepped structure 200, the transparent conductive layer 104, the first electrode 105 and the second electrode 106. The first through hole 110 penetrates the reflective layer 107 and communicates with the first electrode 105, and the second through hole 111 penetrates the reflective layer 107 and communicates with the second electrode 106.

[0123] S27. Fabricate a first electrode pad and a second electrode pad, wherein the first electrode pad is connected to the first electrode through a first through hole, and the second electrode pad is connected to the second electrode through a second through hole.

[0124] In this embodiment, the first electrode pad and the second electrode pad are fabricated using physical vapor deposition (PVD) technology.

[0125] In one example, step S27 includes:

[0126] The first step is to maintain a temperature of 20–25°C and a pressure of 5 × 10⁻⁶. -7 ~7×10 -7A first adhesion metal layer with a thickness of 5 to 1000 angstroms is grown under conditions of pa and a evaporation rate of 1 to 3 angstroms / s.

[0127] In this embodiment of the disclosure, the first adhesive metal layer can be a TiW layer. The TiW layer has good adhesion to the reflective layer and stronger adhesion, preventing the electrode pads from falling off at the contact surface with the DBR.

[0128] For example, at a temperature of 23°C and a pressure of 6×10... -7 A first adhesion metal layer with a thickness of 500 angstroms was grown under the conditions of pa and a evaporation rate of 2 angstroms / s.

[0129] In this implementation, the adhesion layer of the above thickness is used, which on the one hand can satisfy the adhesion effect between the reflective layer and the electrode pad, and on the other hand, the thickness will not cause the thickness of the entire light-emitting diode to be too large.

[0130] The second step is to maintain a temperature of 20–25°C and a pressure of 5 × 10⁻⁶. -7 ~7×10 -7 Flexible metal layers with a thickness of 5,000 to 20,000 angstroms were grown under conditions of pa and a evaporation rate of 7 to 9 angstroms / s.

[0131] In this embodiment of the disclosure, the flexible metal layer may be an Ag layer, a Cu layer, or a Sn layer.

[0132] For example, the flexible metal layer is an Ag layer. The Ag layer has high plasticity and good elasticity, which allows the Ag layer to deform under the action of external force and return to its original state after the external force is removed. At the same time, the Ag flexible metal layer also has excellent electrical and thermal conductivity.

[0133] For example, at a temperature of 23°C and a pressure of 6×10... -7 A flexible metal layer with a thickness of 15,000 angstroms was grown under the conditions of pa and a evaporation rate of 8 angstroms / s.

[0134] In this implementation, the use of a flexible metal layer of the aforementioned thickness satisfies both the plasticity and good elasticity of the flexible metal layer, while also ensuring its excellent electrical and thermal conductivity.

[0135] The third step is to maintain a temperature of 70–80°C and a pressure of 5 × 10⁻⁶. -7 ~7×10 -7 A protective metal layer with a thickness of 1000–3000 angstroms is grown under conditions of pa and a vapor deposition rate of 2–4 angstroms / s.

[0136] In this embodiment, the protective metal layer can be a Ni layer, which has excellent oxidation resistance and can effectively protect the flexible metal layer.

[0137] For example, at a temperature of 75°C and a pressure of 6×10... -7 A protective metal layer with a thickness of 2000 angstroms was grown at a vapor deposition rate of 3 angstroms / s.

[0138] In this implementation, the protective metal layer of the aforementioned thickness can effectively protect the flexible metal layer while ensuring that the overall thickness of the light-emitting diode is not excessive.

[0139] The fourth step involves operating at a temperature of 20–25°C and a pressure of 5 × 10⁻⁶. -7 ~7×10 -7 A second adhesion metal layer with a thickness of 500–2000 angstroms is grown under conditions of pa and a evaporation rate of 1–3 angstroms / s.

[0140] In this embodiment of the disclosure, the second adhesive metal layer can be a TiW layer, which has good adhesion and stronger adhesion.

[0141] For example, at a temperature of 23°C and a pressure of 6×10... -7 A second adhesion metal layer with a thickness of 1500 angstroms was grown under the conditions of pa and a evaporation rate of 2 angstroms / s.

[0142] In this implementation, the second adhesion layer of the aforementioned thickness can satisfy the adhesion effect between the reactive metal layer and the electrode pads, while ensuring that the thickness does not result in an excessively large overall thickness of the light-emitting diode.

[0143] The fifth step involves operating at a temperature of 70–80°C and a pressure of 5 × 10⁻⁶. -7 ~7×10 -7 A reactive metal layer with a thickness of 5000–10000 angstroms was grown under conditions of pa and a evaporation rate of 4–6 angstroms / s.

[0144] In this embodiment, the reactive metal layer can be a Ni layer, which can react with solder paste to achieve a die-bonding effect and fix the electrode pads on the support.

[0145] For example, at a temperature of 75°C and a pressure of 6×10... -7 A reactive metal layer with a thickness of 7000 angstroms was grown under the conditions of pa and a evaporation rate of 5 angstroms / s.

[0146] In this implementation, the use of the aforementioned thickness of the reactive metal layer ensures that the reactive metal layer can fully react with the solder paste to achieve the effect of die bonding and fix the electrode pads on the support. On the other hand, this thickness does not result in an excessively large thickness of the entire light-emitting diode.

[0147] Step 6: At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶...-7 ~7×10 -7 Conductive metal layers with a thickness of 500–2000 angstroms are grown under conditions of pa and a evaporation rate of 1–3 angstroms / s.

[0148] In this embodiment, the conductive metal layer can be an Au layer, which has good conductivity and facilitates the testing of photoelectric parameters of the chip.

[0149] For example, at a temperature of 23°C and a pressure of 6×10... -7 A conductive metal layer with a thickness of 1500 angstroms was grown under the conditions of pa and a evaporation rate of 2 angstroms / s.

[0150] In this implementation, using a conductive metal layer of the aforementioned thickness ensures good conductivity of the conductive metal layer while preventing the overall thickness of the light-emitting diode from becoming too large.

[0151] In the embodiments disclosed herein, the use of the above-described temperature, pressure, and speed to fabricate each metal layer ensures the mechanical and electrical properties of each metal layer.

[0152] It is worth noting that a photoresist mask needs to be formed on the reflective layer before the first step, and then the various metal layers are grown. The mask is removed after the sixth step.

[0153] S28. A passivation layer is fabricated, which covers the surface of the reflective layer.

[0154] In one example, step S28 includes:

[0155] A SiO2 layer is fabricated on the surface of the stepped structure using plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD) techniques to form a passivation layer.

[0156] In the embodiments disclosed herein, the passivation layer may also be a transparent insulating material such as Al2O3, and the material of the passivation layer is not limited in this disclosure.

[0157] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: an epitaxial structure (1000), a reflective layer (107), and an electrode structure (10); The epitaxial structure (1000) includes a first semiconductor layer (101), an active layer (102), and a second semiconductor layer (103) stacked sequentially. The first semiconductor layer (101), the active layer (102), and the second semiconductor layer (103) form a stepped structure (200). The reflective layer (107) covers the surface of the stepped structure (200). The electrode structure (10) includes a first electrode (105), a first electrode pad (108), a second electrode (106), and a second electrode pad (109). The first electrode pad (108) and the second electrode pad (109) each include a first adhesion metal layer (201), a flexible metal layer (202), a protective metal layer (203), a second adhesion metal layer (204), a reactive metal layer (205), and a conductive metal layer (206) stacked sequentially.

2. The light-emitting diode according to claim 1, characterized in that, The flexible metal layer (202) is an Ag layer, a Cu layer, or a Sn layer.

3. The light-emitting diode according to claim 2, characterized in that, The flexible metal layer (202) is an Ag layer.

4. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The thickness of the flexible metal layer (202) is 5000 to 20000 angstroms.

5. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The first adhesion metal layer (201) is a TiW layer, the protective metal layer (203) is a Ni layer, the second adhesion metal layer (204) is a TiW layer, the reactive metal layer (205) is a Ni layer, and the conductive metal layer (206) is an Au layer.

6. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The first adhesive metal layer (201) has a thickness of 5 to 1000 angstroms, the protective metal layer (203) has a thickness of 1000 to 3000 angstroms, the second adhesive metal layer (204) has a thickness of 500 to 2000 angstroms, the reactive metal layer (205) has a thickness of 5000 to 10000 angstroms, and the conductive metal layer (206) has a thickness of 500 to 2000 angstroms.

7. A method for fabricating a light-emitting diode, characterized in that, The method includes: A first semiconductor layer, an active layer, and a second semiconductor layer are fabricated in sequence, and the first semiconductor layer, the active layer, and the second semiconductor layer constitute an epitaxial structure. The extensional structure is graphically processed to form a stepped structure; A reflective layer is fabricated on the epitaxial structure, the reflective layer covering the stepped structure; An electrode structure is fabricated that connects the reflective layer to the epitaxial structure. The electrode structure includes a first electrode, a first electrode pad, a second electrode, and a second electrode pad. The first electrode is located on a stepped surface, and the second electrode is located on the surface of a transparent conductive layer. The first electrode pad penetrates the reflective layer and is connected to the first electrode, and the second electrode pad penetrates the reflective layer and is connected to the second electrode. The first electrode pad and the second electrode pad include a first adhesion metal layer, a flexible metal layer, a protective metal layer, a second adhesion metal layer, a reactive metal layer, and a conductive metal layer stacked sequentially.

8. The method for fabricating a light-emitting diode according to claim 7, characterized in that, The fabrication of the electrode structure that connects the reflective layer and the epitaxial structure includes: Before fabricating the reflective layer, the first electrode and the second electrode are fabricated, with the first electrode located on the stepped surface and the second electrode located on the surface of the transparent conductive layer. After the reflective layer is fabricated, it is patterned to form a first through-hole and a second through-hole. The first electrode pad and the second electrode pad are fabricated. The first electrode pad is connected to the first electrode through the first through hole, and the second electrode pad is connected to the second electrode through the second through hole.

9. The method for fabricating a light-emitting diode according to claim 8, characterized in that, The fabrication of the first electrode pad and the second electrode pad includes: At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The first adhesion metal layer with a thickness of 5 to 1000 angstroms is grown under the conditions of pa and a evaporation rate of 1 to 3 angstroms / s. At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The flexible metal layer with a thickness of 5,000 to 20,000 angstroms is grown under conditions of pa and a evaporation rate of 7 to 9 angstroms / s. At a temperature of 70–80℃ and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The protective metal layer with a thickness of 1000-3000 angstroms is grown under the conditions of pa and a evaporation rate of 2-4 angstroms / s. At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 A second adhesion metal layer with a thickness of 500 to 2000 angstroms is grown under conditions of pa and a evaporation rate of 1 to 3 angstroms / s. At a temperature of 70–80℃ and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The reactive metal layer with a thickness of 5000-10000 angstroms is grown under conditions of pa and a evaporation rate of 4-6 angstroms / s. At a temperature of 20–25°C and a pressure of 5 × 10⁻⁶ -7 ~7×10 -7 The conductive metal layer with a thickness of 500 to 2000 angstroms is grown under conditions of pa and a evaporation rate of 1 to 3 angstroms / s.

10. The method for fabricating a light-emitting diode according to any one of claims 7 to 9, characterized in that, The flexible metal layer is an Ag layer, a Cu layer, or a Sn layer.

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