Light emitting diode and preparation method thereof

Abstract

The invention provides a light emitting diode and a preparation method thereof. The light-emitting diode comprises a substrate, an epitaxial structure, an electrode, an electrode bonding pad, a reflecting layer and a welding metal structure, the epitaxial structure is located on the substrate, the epitaxial structure is provided with an isolation groove formed in the substrate, the epitaxial structure is of a step structure, the step structure is provided with a step top surface and a step bottom surface, the electrode comprises a first electrode and a second electrode, and the electrode bonding pad comprises a first electrode bonding pad and a second electrode bonding pad; the welding metal structure is located in the isolation groove; the first electrode is located on the top face of the step, the second electrode is located on the bottom face of the step, the reflecting layer covers the substrate, the epitaxial structure, the first electrode and the second electrode, the first electrode bonding pad penetrates through the reflecting layer to be connected with the first electrode, and the second electrode bonding pad penetrates through the reflecting layer to be connected with the second electrode.

Description

Technical Field

[0001] The present disclosure relates to the field of light-emitting devices, and particularly to a light-emitting diode and a method for manufacturing the same. Background Art

[0002] A light-emitting diode (LED) is a semiconductor device that can emit light.

[0003] Related technologies provide a light-emitting diode. The structure of the light-emitting diode includes a substrate, an epitaxial structure, electrodes, electrode pads, and a reflective layer. The epitaxial structure is located on the substrate, the electrodes are located on the epitaxial structure, the reflective layer covers the substrate, the epitaxial structure, and the electrodes, and the electrode pads pass through the reflective layer and are connected to the electrodes.

[0004] The light-emitting diode with the above structure has problems such as poor soldering and easy detachment of the light-emitting diode, and the reliability of the light-emitting diode is low. Summary of the Invention

[0005] Embodiments of the present disclosure provide a light-emitting diode and a method for manufacturing the same, which can significantly increase the soldering area of the pads and improve the adhesion force during soldering of the light-emitting diode. The technical solutions are as follows:

[0006] On the one hand, a light-emitting diode is provided. The light-emitting diode includes: a substrate, an epitaxial structure, electrodes, electrode pads, a reflective layer, and a soldering metal structure;

[0007] The epitaxial structure is located on the substrate. The epitaxial structure has isolation grooves opened to the substrate. The epitaxial structure has a stepped structure. The stepped structure has a stepped top surface and a stepped bottom surface. The electrodes include a first electrode and a second electrode. The electrode pads include a first electrode pad and a second electrode pad. The soldering metal structure is located in the isolation grooves;

[0008] The first electrode is located on the stepped top surface, the second electrode is located on the stepped bottom surface. The reflective layer covers the substrate, the epitaxial structure, the first electrode, and the second electrode. The first electrode pad passes through the reflective layer and is connected to the first electrode. The second electrode pad passes through the reflective layer and is connected to the second electrode.

[0009] Optionally, the soldering metal structure includes a first metal structure. The first metal structure is located on the surface of the reflective layer and is arranged around the edge of the light-emitting diode.

[0010] Optionally, the first metal structure includes a plurality of first metal blocks, which are divided into at least two groups. The distance between the first metal blocks within each group is less than the distance between the first metal blocks in different groups, and the interval between the two groups of first metal blocks corresponds to the interval between the first electrode pad and the second electrode pad.

[0011] Optionally, the welding metal structure further includes a second metal structure, which is located between the reflective layer and the substrate. The side wall of the second metal structure is exposed, and the first metal structure is arranged around the edge of the light-emitting diode.

[0012] Optionally, the second metal structure includes a plurality of second metal blocks, which are divided into at least two groups. The distance between the second metal blocks within each group is less than the distance between the second metal blocks in different groups, and the interval between the two groups of second metal blocks corresponds to the interval between the first electrode pad and the second electrode pad.

[0013] Optionally, the projections of the first metal block and the second metal block on the substrate are rectangular or rhombic.

[0014] Optionally, the widths of the first metal structure and the second metal structure are 1 - 10 μm.

[0015] On the other hand, a method for manufacturing a light-emitting diode is provided, and the method includes:

[0016] Fabricating an epitaxial structure on a substrate, the epitaxial structure having isolation grooves opened to the substrate, the epitaxial structure being a stepped structure having a stepped top surface and a stepped bottom surface;

[0017] Fabricating a first electrode and a second electrode, the first electrode being located on the stepped top surface and the second electrode being located on the stepped bottom surface;

[0018] Fabricating a reflective layer, the reflective layer covering the substrate, the epitaxial structure, the first electrode, and the second electrode;

[0019] Fabricating a first electrode pad and a second electrode pad, the first electrode pad passing through the reflective layer to connect with the first electrode, and the second electrode pad passing through the reflective layer to connect with the second electrode;

[0020] Fabricating a welding metal structure, the welding metal structure being located in the isolation grooves.

[0021] Optionally, the welding metal structure includes a first metal structure, the first metal structure being located on the surface of the reflective layer and the first metal structure being arranged around the edge of the light-emitting diode;

[0022] The first metal structure is fabricated on the same layer as the first electrode pad and the second electrode pad.

[0023] Optionally, the welding metal structure further includes a second metal structure, which is located between the reflective layer and the substrate, and the second metal structure is arranged around the edge of the light-emitting diode;

[0024] The second metal structure is fabricated on the same layer as the first electrode and the second electrode.

[0025] The beneficial effects brought by the technical solutions provided by the embodiments of the present disclosure are as follows:

[0026] In the embodiments of the present disclosure, in the light-emitting diode, by providing a welding metal structure on the isolation groove, the welding metal structure can be used as a pad of the light-emitting diode just like the first electrode pad and the second electrode pad, thereby increasing the welding area. Increasing the welding area can increase the adhesion of welding, avoid the light-emitting diode from falling off, and improve the reliability of the light-emitting diode. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0029] Figure 2 It is a top-view structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0030] Figure 3 It is a top-view structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0031] Figure 4 It is a top-view structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0032] Figure 5 It is a top-view structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0033] Figure 6 It is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure;

[0034] Figure 7 It is a flowchart of another method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure.

[0035] The reference numerals are as follows:

[0036] 10: epitaxial structure;

[0037] 101: substrate; 102: first semiconductor layer; 103: active layer; 104: second semiconductor layer; 105: electrode; 106: electrode pad; 107: reflective layer; 108: first metal structure; 109: second metal structure; 110: current blocking layer; 111: transparent conductive layer; 189: welding metal structure;

[0038] 180: first metal block; 190: second metal block;

[0039] 1051: first electrode; 1052: second electrode;

[0040] 1061: first electrode pad; 1062: second electrode pad;

[0041] 1001: isolation groove; 1002: top surface of the step; 1003: bottom surface of the step;

[0042] H1: thickness of the first metal structure; H2: thickness of the second metal structure; W1: width of the first metal structure; W2: width of the second metal structure. Detailed implementation manners

[0043] To make the objectives, technical solutions and advantages of the present disclosure clearer, the following will further describe the implementation manners of the present disclosure in detail with reference to the accompanying drawings.

[0044] Figure 1 The following is a schematic structural diagram of a light-emitting diode provided in an embodiment of the present disclosure. Refer to Figure 1 , the light-emitting diode includes: a substrate 101, an epitaxial structure 10, an electrode 105, an electrode pad 106, a reflective layer 107, and a welding metal structure 189.

[0045] Among them, the epitaxial structure 10 is located on the substrate 101. The epitaxial structure 10 has an isolation groove 1001 opened to the substrate 101. The epitaxial structure 10 has a stepped structure. The stepped structure has a top surface 1002 of the step and a bottom surface 1003 of the step. The electrode 105 includes a first electrode 1051 and a second electrode 1052. The electrode pad 106 includes a first electrode pad 1061 and a second electrode pad 1062; the welding metal structure 189 is located in the isolation groove 1001.

[0046] The first electrode 1051 is located on the top surface 1002 of the step, the second electrode 1052 is located on the bottom surface 1003 of the step, the reflective layer 107 covers the substrate 101, the epitaxial structure 10, the first electrode 1051 and the second electrode 1052, the first electrode pad 1061 passes through the reflective layer 107 and is connected to the first electrode 1051, and the second electrode pad 1062 passes through the reflective layer 107 and is connected to the second electrode 1052.

[0047] It should be noted that the welding metal structure 189 is located in the isolation groove 1001 and is insulated from the electrode 105, the electrode pad 106 and the epitaxial structure 10.

[0048] Figure 1 Shown are two un-split light-emitting diode chips, and after cutting, the two light-emitting diode chips are disconnected from Figure 1 the middle.

[0049] In the embodiment of the present disclosure, in the light-emitting diode, by providing a welding metal structure on the isolation groove, the welding metal structure can be used as a pad of the light-emitting diode like the first electrode pad and the second electrode pad, thereby increasing the welding area. Increasing the welding area can increase the adhesion of welding, avoid the light-emitting diode from falling off, and improve the reliability of the light-emitting diode.

[0050] As Figure 1 shown, the welding metal structure 189 includes a first metal structure 108. The first metal structure 108 is located on the surface of the reflective layer 107, and the first metal structure 108 is arranged around the edge of the light-emitting diode.

[0051] In this implementation manner, the first metal structure is arranged on the surface of the reflective layer, which is convenient for using the first metal structure as the welding metal to realize the welding of the light-emitting diode to the outside. Moreover, the first metal structure is arranged around the edge of the light-emitting diode to form an annular structure, ensuring a sufficient welding area.

[0052] Figure 2 This is a top view structure diagram of a light-emitting diode provided by an embodiment of the present disclosure. Refer to Figure 2 , the first metal structure 108 includes a plurality of first metal blocks 180. The plurality of first metal blocks 180 are divided into at least two groups (such as a and b in the figure). The spacing between the first metal blocks 180 within each group is less than the spacing between the first metal blocks 180 in different groups. The interval between the two groups of first metal blocks 180 corresponds to the interval between the first electrode pad 1061 and the second electrode pad 1062.

[0053] Exemplarily, the proportion of at least two groups of first metal blocks 180 in a circle can be 3 / 4, and the proportion of the gap between each group can be 1 / 4.

[0054] In this implementation, the first metal structure is set as a plurality of first metal blocks, and each first metal block is independent of each other, so that the soldering effects of the first metal blocks are independent of each other, and the influence of poor soldering effect on the overall effect can be avoided. At the same time, the first metal blocks are grouped and designed, and the interval of the grouped design corresponds to the interval between two pads, so as to avoid the influence of the metal blocks on the insulation effect and electric field distribution between the pads, etc.

[0055] Refer to again Figure 2 , the projections of the plurality of first metal blocks 180 in the first metal structure 108 on the substrate 101 are rectangular, and the first metal blocks 180 are arranged around the edge of the light-emitting diode.

[0056] Figure 3 FIG. is a top view structure schematic diagram of a light-emitting diode provided by an embodiment of the present disclosure. Refer to Figure 3 , the projections of the plurality of first metal blocks 180 in the first metal structure 108 on the substrate 101 are strip-shaped, and the first metal blocks 180 are arranged around the edge of the light-emitting diode.

[0057] In the embodiment of the present disclosure, the welding metal structure 189 further includes a second metal structure 109. The second metal structure 109 is located between the reflective layer 107 and the substrate 101, the side wall of the second metal structure 109 is exposed, and the first metal structure 108 is arranged around the edge of the light-emitting diode.

[0058] In this implementation, by providing a second metal structure with an exposed side wall, soldering can be performed through the side wall of the second metal structure on the basis of the first metal structure, so as to realize the soldering of the light-emitting diode to the outside, thereby increasing the soldering area. Moreover, the second metal structure is arranged around the edge of the light-emitting diode to form an annular structure, ensuring a sufficient soldering area.

[0059] Figure 4 FIG. is a top view structure schematic diagram of a light-emitting diode provided by an embodiment of the present disclosure. Refer to Figure 4 , the second metal structure 109 includes a plurality of second metal blocks 190. The plurality of second metal blocks 190 are divided into at least two groups (such as c and d in the figure), the distance between the second metal blocks 190 within each group is less than the distance between the second metal blocks 190 in different groups, and the interval between the two groups of second metal blocks 190 corresponds to the interval between the first electrode pad 1061 and the second electrode pad 1062.

[0060] Exemplarily, the proportion of at least two groups of second metal blocks 190 in a circle can be 3 / 4, and the proportion of the gap between each group can be 1 / 4.

[0061] In this implementation manner, the second metal structure is arranged as a plurality of second metal blocks, and each second metal block is independent of each other, so that the soldering effects of the second metal blocks are independent of each other, and the influence of poor soldering effect on the overall effect can be avoided. At the same time, the second metal blocks are designed in groups, and the intervals of the grouped design correspond to the intervals between two pads, so as to avoid the influence of the metal blocks on the insulation effect and electric field distribution between the pads, etc.

[0062] Refer to again Figure 4 , the projections of the plurality of second metal blocks 190 in the second metal structure 109 on the substrate 101 are rhombic, and the second metal blocks 190 are arranged around the edge of the light-emitting diode.

[0063] Figure 5 is a schematic top view structure of a light-emitting diode provided by an embodiment of the present disclosure. Refer to Figure 5 , the projections of the plurality of second metal blocks 190 in the second metal structure 109 on the substrate 101 are strip-shaped, and the second metal blocks 190 are arranged around the edge of the light-emitting diode.

[0064] Adopt Figures 2 to 5 The metal block pattern in can facilitate the patterning production of the metal block and subsequent soldering, and improve the soldering adhesion of the light-emitting diode.

[0065] In other examples, the projections of the first metal block 180 and the second metal block 190 on the substrate 101 can also be triangular, circular or other shapes, and the embodiments of the present disclosure do not limit this.

[0066] In the embodiment of the present disclosure, the thicknesses H1 and H2 of the first metal structure 108 and the second metal structure 109 can be 0.1 - 10 μm. The first metal structure and the second metal structure manufactured with the above thicknesses can not only ensure the soldering requirements, but also enable the first metal structure 108 to be manufactured on the same layer as the electrode pad, and the second metal structure 109 to be manufactured on the same layer as the electrode, reducing the manufacturing complexity.

[0067] In the embodiment of the present disclosure, the thicknesses H1 and H2 of the first metal structure 108 and the second metal structure 109 can be the same.

[0068] Exemplarily, the thicknesses of the first metal structure 108 and the second metal structure 109 are 5 μm.

[0069] In other embodiments, the thicknesses of the first metal structure 108 and the second metal structure 109 can also be different.

[0070] In the embodiments of the present disclosure, the widths W1 and W2 of the first metal structure 108 and the second metal structure 109 can be 1-10 μm. The above widths are not too wide to cause leakage due to the first metal structure and the second metal structure being too close to the sidewalls of the epitaxial structure, nor too narrow to cause a decrease in the soldering effect of die bonding reflow soldering and affect the overall effect.

[0071] Exemplarily, the widths of the first metal structure 108 and the second metal structure 109 are 5 μm.

[0072] Among them, the widths W1 and W2 of the first metal structure 108 and the second metal structure 109 can refer to the width of the rectangle, the width of the rhombus, etc. in the foregoing drawings.

[0073] In the embodiments of the present disclosure, the first metal structure 108 and the second metal structure 109 can be composed of single-layer or multi-layer metals.

[0074] Exemplarily, the first metal structure 108 and the second metal structure 109 can be a metal stack composed of Ti, Al, Pt, Ni, and Au metals. The above metal stack can be fabricated on the same layer as the electrode and the electrode pad.

[0075] In the embodiments of the present disclosure, the substrate 101 can be any one of substrates such as a sapphire patterned substrate, an Si substrate, and an SiC substrate, and the embodiments of the present disclosure do not limit the material of the substrate 101.

[0076] Exemplarily, the substrate 101 is a sapphire patterned substrate.

[0077] In the embodiments of the present disclosure, the epitaxial structure 10 includes a first semiconductor layer 102, an active layer 103, and a second semiconductor layer 104.

[0078] In the embodiments of the present disclosure, the first semiconductor layer 102 can be an N-type semiconductor layer, and the second semiconductor layer 104 can be a P-type semiconductor layer.

[0079] For example, the first semiconductor layer 102 can be an N-type GaN layer, and the second semiconductor layer 104 can be a P-type GaN layer.

[0080] In other embodiments, the first semiconductor layer 102 can be a P-type semiconductor layer, and the second semiconductor layer 104 can be an N-type semiconductor layer.

[0081] In the embodiments of the present disclosure, the active layer 103 can be a multi-quantum well layer. For example, the multi-quantum well layer can be an InGaN / GaN multi-quantum well structure.

[0082] In an embodiment of the present disclosure, the first electrode 1051, the second electrode 1052, the first electrode pad 1061, and the second electrode pad 1062 may be a metal stack composed of metals such as Ti, Al, Pt, Ni, and Au.

[0083] In an embodiment of the present disclosure, the reflective layer 107 may be a Distributed Bragg Reflector (DBR) layer, and the DBR layer is a stack composed of alternately arranged SiO2 and Ti3O5 periods. The DBR layer has good reflectivity and improves the brightness of the light-emitting diode.

[0084] In an embodiment of the present disclosure, the alternating period of the SiO2 layer and the Ti3O5 layer may be 5 to 13 periods.

[0085] Exemplarily, the alternating period of the SiO2 layer and the Ti3O5 layer may be 8 periods.

[0086] In an embodiment of the present disclosure, the above light-emitting diode may further include: a current blocking layer 110 and a transparent conductive layer 111.

[0087] In an embodiment of the present disclosure, the current blocking layer 110 is on the epitaxial structure 10, and the transparent conductive layer 111 wraps the current blocking layer 110 on the epitaxial structure 10.

[0088] In an embodiment of the present disclosure, the current blocking layer 110 may be an AlGaN or SiO2 layer.

[0089] Exemplarily, the current blocking layer 110 is a SiO2 current blocking layer.

[0090] In an embodiment of the present disclosure, the transparent conductive layer 111 may be an Indium Tin Oxide (ITO) layer. ITO has good transparency and conductivity, and it allows light to pass through while also conducting current to form an electrical connection.

[0091] It should be noted that in an embodiment of the present disclosure, structures may be selectively added or reduced based on the above structure of the light-emitting diode, and the present disclosure does not limit this.

[0092] Figure 6 It is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure. Refer to Figure 6 The method steps include:

[0093] S11. Fabricate an epitaxial structure on a substrate. The substrate has isolation grooves, and the epitaxial structure has a stepped structure with a stepped top surface and a stepped bottom surface.

[0094] S12. Fabricate the first electrode and the second electrode, where the first electrode is located on the top surface of the step and the second electrode is located on the bottom surface of the step.

[0095] S13. Fabricate the reflective layer, which covers the substrate, the epitaxial structure, the first electrode, and the second electrode.

[0096] S14. Fabricate the first electrode pad and the second electrode pad. The first electrode pad passes through the reflective layer and is connected to the first electrode, and the second electrode pad passes through the reflective layer and is connected to the second electrode.

[0097] S15. Fabricate the welding metal structure, which is located in the isolation groove.

[0098] It should be noted that the order of step S15 and the foregoing steps is not limited. For example, step S15 includes 2 sub-steps, which are respectively executed simultaneously with S12 and S14.

[0099] Alternatively, step S15 includes 1 sub-step, which is executed simultaneously with S14.

[0100] In the embodiment of the present disclosure, in the light-emitting diode, by providing a welding metal structure on the isolation groove, the welding metal structure can be used as a pad of the light-emitting diode like the first electrode pad and the second electrode pad, thereby increasing the welding area. Increasing the welding area can increase the adhesion of welding, avoid the light-emitting diode from falling off, and improve the reliability of the light-emitting diode.

[0101] Figure 7 It is a flowchart of another method for fabricating a light-emitting diode provided by the embodiment of the present disclosure. Refer to Figure 7 , and the steps of this method include:

[0102] S21. Sequentially form a first semiconductor layer, an active layer, and a second semiconductor layer on the substrate. The second semiconductor layer, the active layer, and the first semiconductor layer constitute an epitaxial structure.

[0103] Among them, the substrate can be any one of substrates such as a sapphire patterned substrate, an Si substrate, and an SiC substrate.

[0104] In one example, step S21 includes:

[0105] The first step is to fabricate the first semiconductor layer.

[0106] In the embodiment of the present disclosure, the first semiconductor layer is an N-type GaN layer.

[0107] The second step is to fabricate the active layer.

[0108] In the embodiment of the present disclosure, the active layer is a multi-quantum well layer. For example, the multi-quantum well layer can be an InGaN / GaN multi-quantum well structure.

[0109] Step 3: fabricate the second semiconductor layer.

[0110] In the embodiment of the present disclosure, the second semiconductor layer is a P-type GaN layer.

[0111] In the embodiment of the present disclosure, the first semiconductor layer, the active layer, and the second semiconductor layer are sequentially stacked on the substrate.

[0112] S22: Pattern the epitaxial structure to form a step structure and isolation grooves. The step structure has a step top surface and a step bottom surface. The step bottom surface of the step structure is located within the epitaxial structure, the step top surface of the step structure is located on the second semiconductor layer, and the bottom of the isolation groove is located on the substrate.

[0113] In the embodiment of the present disclosure, the epitaxial structure is patterned by inductively coupled plasma (ICP) etching.

[0114] S23: Fabricate a current blocking layer on the surface of the epitaxial structure.

[0115] In the embodiment of the present disclosure, the current blocking layer can be an AlGaN or SiO2 layer.

[0116] Exemplarily, the current blocking layer is a SiO2 current blocking layer.

[0117] S24: Fabricate a transparent conductive layer on the surface of the epitaxial structure. The transparent conductive layer wraps the current blocking layer.

[0118] In the embodiment of the present disclosure, the transparent conductive layer can be an ITO layer. ITO has good transparency and conductivity. It allows light to pass through while also conducting current to form an electrical connection.

[0119] S25: Fabricate a first electrode, a second electrode, and a second metal structure. The first electrode is on the step top surface of the epitaxial structure, the second electrode is on the step bottom surface of the epitaxial structure, and the second metal structure is on the substrate within the isolation groove and is arranged around the edge of the light-emitting diode.

[0120] In the embodiment of the present disclosure, the first electrode, the second electrode, and the second metal structure can be composed of a single layer or multiple layers of metal.

[0121] Exemplarily, the first electrode, the second electrode, and the second metal structure can be a metal stack composed of Ti, Al, Pt, Ni, and Au metals.

[0122] In the embodiment of the present disclosure, the second metal structure includes a plurality of second metal blocks. The plurality of second metal blocks are divided into at least two groups. The spacing between the second metal blocks within each group is less than the spacing between the second metal blocks in different groups. The interval between the two groups of second metal blocks corresponds to the interval between the first electrode pad and the second electrode pad.

[0123] In this implementation, the second metal structure is set as a plurality of second metal blocks, and each second metal block is independent of each other, so that the welding effects of the second metal blocks are independent of each other, and the influence of poor welding effect on the overall effect can be avoided. At the same time, the second metal blocks are designed in groups, and the interval of the group design corresponds to the interval between two pads, so as to avoid the influence of the metal blocks on the insulation effect and electric field distribution between the pads, etc.

[0124] In one example, the projections of the plurality of second metal blocks in the second metal structure on the substrate are rhombuses, and the second metal blocks are arranged around the edge of the light-emitting diode.

[0125] In another example, the projections of the plurality of second metal blocks in the second metal structure on the substrate are long strips, and the second metal blocks are arranged around the edge of the light-emitting diode.

[0126] Exemplarily, this step includes:

[0127] Fabricate a first photoresist mask layer, the first photoresist mask layer having a first pattern opening corresponding to the first electrode, a second pattern opening corresponding to the second electrode, and a third pattern opening corresponding to the second metal structure;

[0128] Under the shielding of the first photoresist mask layer, perform metal layer electroplating;

[0129] Remove the first photoresist mask layer and the metal layer on the first photoresist mask layer, leaving the metal layer in the three pattern openings, to obtain the first electrode, the second electrode, and the second metal structure.

[0130] In the embodiments of the present disclosure, the thickness of the second metal structure may be 0.1 - 10 μm. The second metal structure fabricated with the above thickness can not only ensure the welding requirements, but also be fabricated on the same layer as the electrode, reducing the fabrication complexity.

[0131] In the embodiments of the present disclosure, the width of the second metal structure may be 1 - 10 μm. The above width is not too wide to cause leakage due to the second metal structure being too close to the sidewall of the epitaxial structure, nor too narrow to cause a decrease in the welding effect of die bonding reflow soldering and affect the overall effect.

[0132] Exemplarily, the width of the second metal structure is 5 μm.

[0133] Wherein, the width of the second metal structure may refer to the width of the rectangle, the width of the rhombus, etc. in the foregoing drawings.

[0134] S26. Fabricate a reflective layer, the reflective layer covering the substrate, the epitaxial structure, the first electrode, the second electrode, and the second metal structure.

[0135] Wherein, the sidewalls of the second metal structure are exposed.

[0136] In the embodiments of the present disclosure, a plasma enhanced chemical vapor deposition (PECVD) is used to fabricate a reflective layer.

[0137] In the embodiments of the present disclosure, the reflective layer may be a DBR layer, and the DBR layer is a stack formed by alternately arranging SiO2 and Ti3O5 in a cycle. The DBR layer has good reflectivity and improves the brightness of the light emitting diode.

[0138] In the embodiments of the present disclosure, an optical coating machine is used to alternately fabricate SiO2 layers and Ti3O5 layers, and the alternating cycle may be 5 to 13 cycles.

[0139] Exemplarily, an optical coating machine is used to alternately fabricate SiO2 layers and Ti3O5 layers, and the alternating cycle may be 8 cycles.

[0140] S27. Fabricate a first electrode pad, a second electrode pad, and a first metal structure. The first electrode pad passes through the reflective layer and is connected to the first electrode, the second electrode pad passes through the reflective layer and is connected to the second electrode, and the first metal structure is located on the surface of the reflective layer and is arranged around the edge of the light emitting diode.

[0141] In the embodiments of the present disclosure, the first electrode pad, the second electrode pad, and the first metal structure may be composed of single-layer or multi-layer metals.

[0142] In the embodiments of the present disclosure, the first electrode pad, the second electrode pad, and the first metal structure may be a metal stack composed of Ti, Al, Pt, Ni, and Au metals.

[0143] In the embodiments of the present disclosure, the first metal structure includes a plurality of first metal blocks. The plurality of first metal blocks are divided into at least two groups. The spacing between the first metal blocks within each group is less than the spacing between the first metal blocks in different groups, and the interval between the two groups of first metal blocks corresponds to the interval between the first electrode pad and the second electrode pad.

[0144] In this implementation manner, the first metal structure is arranged as a plurality of first metal blocks, and each first metal block is independent of each other, so that the welding effects of each first metal block are independent of each other, and the influence of poor welding effect on the overall effect can be avoided. At the same time, the first metal blocks are grouped and designed, and the interval of the grouped design corresponds to the interval between the two pads, so as to avoid the influence of the metal blocks on the insulation effect and electric field distribution between the pads.

[0145] In one example, the projections of the plurality of first metal blocks in the first metal structure on the substrate are rectangles, and the first metal blocks are arranged around the edge of the light emitting diode.

[0146] In another example, the projections of the plurality of first metal blocks in the first metal structure on the substrate are strip-shaped, and the first metal blocks are arranged around the edge of the light-emitting diode.

[0147] Exemplarily, this step includes:

[0148] Fabricating a second photoresist mask layer, the second photoresist mask layer having a fourth pattern opening corresponding to the first electrode pad, a fifth pattern opening corresponding to the second electrode pad, and a sixth pattern opening corresponding to the first metal structure;

[0149] Performing metal layer electroplating under the shielding of the second photoresist mask layer;

[0150] Removing the second photoresist mask layer and the metal layer on the second photoresist mask layer, leaving the metal layer in the three pattern openings to obtain the first electrode pad, the second electrode pad, and the first metal structure.

[0151] In the embodiments of the present disclosure, the thickness of the first metal structure can be 0.1 - 10 μm. The first metal structure fabricated with the above thickness can not only ensure the welding requirements, but also enable the first metal structure to be fabricated on the same layer as the electrode pad, reducing the fabrication complexity.

[0152] In the embodiments of the present disclosure, the thicknesses of the first metal structure and the second metal structure can be the same.

[0153] Exemplarily, the thicknesses of the first metal structure and the second metal structure are 5 μm.

[0154] In other embodiments, the thicknesses of the first metal structure and the second metal structure can also be different.

[0155] In the embodiments of the present disclosure, the width of the first metal structure can be 1 - 10 μm. The above width is not too wide to cause the first metal structure and the second metal structure to be too close to the side wall of the epitaxial structure, resulting in leakage, nor too narrow to cause the soldering effect of the die bonding reflow soldering to decline and affect the overall effect.

[0156] Exemplarily, the width of the first metal structure is 5 μm.

[0157] Wherein, the width of the first metal structure can refer to the width of the rectangle, the width of the rhombus, etc. in the foregoing drawings.

[0158] The above are only optional embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A light emitting diode, characterized in that: The light-emitting diode comprises: a substrate (101), an epitaxial structure (10), an electrode (105), an electrode pad (106), a reflective layer (107) and a welding metal structure (189); The epitaxial structure (10) is located on the substrate (101), the epitaxial structure (10) has an isolation groove (1001) opened to the substrate (101), the epitaxial structure (10) is a step structure, the step structure has a step top surface (1002) and a step bottom surface (1003), the electrode (105) includes a first electrode (1051) and a second electrode (1052), the electrode pad (106) includes a first electrode pad (1061) and a second electrode pad (1062); the welding metal structure (189) is located in the isolation groove (1001); The first electrode (1051) is located on the top surface (1002) of the step, the second electrode (1052) is located on the bottom surface (1003) of the step, the reflective layer (107) covers the substrate (101), the epitaxial structure (10), the first electrode (1051) and the second electrode (1052), the first electrode pad (1061) passes through the reflective layer (107) to be connected to the first electrode (1051), and the second electrode pad (1062) passes through the reflective layer (107) to be connected to the second electrode (1052).

2. The light emitting diode according to claim 1, characterized in that: The welding metal structure (189) comprises a first metal structure (108), wherein the first metal structure (108) is located on the surface of the reflective layer (107), and the first metal structure (108) is arranged around the edge of the light-emitting diode.

3. The light emitting diode according to claim 2, characterized in that: The first metal structure (108) includes a plurality of first metal blocks (180), wherein the plurality of first metal blocks (180) are divided into at least two groups, wherein the spacing between the first metal blocks (180) in each group is smaller than the spacing between the first metal blocks (180) in different groups, and the spacing between the two groups of the first metal blocks (180) corresponds to the spacing between the first electrode pad (1061) and the second electrode pad (1062).

4. The light emitting diode according to claim 2 or 3, characterized in that: The welding metal structure (189) further includes a second metal structure (109), wherein the second metal structure (109) is located between the reflective layer (107) and the substrate (101), the side wall of the second metal structure (109) is exposed, and the first metal structure (108) is arranged around the edge of the light-emitting diode.

5. The light emitting diode according to claim 4, characterized in that: The second metal structure (109) includes a plurality of second metal blocks (190), wherein the plurality of second metal blocks (190) are divided into at least two groups, wherein the spacing between the second metal blocks (190) in each group is smaller than the spacing between the second metal blocks (190) in different groups, and the spacing between the two groups of the second metal blocks (190) corresponds to the spacing between the first electrode pad (1061) and the second electrode pad (1062).

6. The light emitting diode according to claim 5, characterized in that: The projections of the first metal block (180) and the second metal block (190) on the substrate (101) are rectangular or rhombus-shaped.

7. The light emitting diode according to claim 4, characterized in that: The thickness of the first metal structure (108) and the second metal structure (109) is 0.1-10 μm; The width of the first metal structure (108) and the second metal structure (109) is 1-10 μm.

8. A method for preparing a light emitting diode, characterized in that: The method comprises: Fabricating an epitaxial structure on a substrate, wherein the epitaxial structure has an isolation groove opened to the substrate, and the epitaxial structure is a step structure, and the step structure has a step top surface and a step bottom surface; Manufacturing a first electrode and a second electrode, wherein the first electrode is located on the top surface of the step, and the second electrode is located on the bottom surface of the step; Manufacturing a reflective layer, wherein the reflective layer covers the substrate, the epitaxial structure, the first electrode and the second electrode; Manufacturing a first electrode pad and a second electrode pad, wherein the first electrode pad passes through the reflective layer and is connected to the first electrode, and the second electrode pad passes through the reflective layer and is connected to the second electrode; A welding metal structure is manufactured, wherein the welding metal structure is located in the isolation groove.

9. The method for preparing a light emitting diode according to claim 8, characterized in that: The welding metal structure comprises a first metal structure, the first metal structure is located on the surface of the reflective layer, and the first metal structure is arranged around the edge of the light emitting diode; The first metal structure is manufactured in the same layer as the first electrode pad and the second electrode pad.

10. The method for preparing a light emitting diode according to claim 9, characterized in that: The welding metal structure further includes a second metal structure, the second metal structure is located between the reflective layer and the substrate, and the second metal structure is arranged around the edge of the light emitting diode; The second metal structure is manufactured in the same layer as the first electrode and the second electrode.

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