Flip-chip type light-emitting diode and manufacturing method thereof

Abstract

To provide a method for manufacturing a flip-chip light emitting diode.SOLUTION: A method for manufacturing a flip-chip light emitting diode includes: a step S1 of providing a first substrate; a step S2 of performing an epitaxial process to form, on the first substrate, a semiconductor structure including a current conductive layer in which a bonding surface is formed and a first electrode facing area and a second electrode facing area are defined; a step S3 of performing a diffusion process toward the bonding surface by using a diffusion material and forming at least one path area with a high doping concentration in the current conductive layer; a step S4 of performing a bonding process to bond a second substrate to the bonding surface; and a step S5 of removing the first substrate and forming a first electrode and a second electrode on a side of the semiconductor structure adjacent to the first substrate. A position of the first electrode faces the first electrode facing area, and a position of +the second electrode faces the second electrode facing area.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a flip-chip type light-emitting diode and a method for manufacturing the same, and more particularly to a flip-chip type light-emitting diode with an increased light-emitting area and reduced current density and a method for manufacturing the same. [Background technology]

[0002] 1, a conventional flip-chip light emitting diode (Flip-Chip LED) 200 mainly includes a P metal electrode 210 and an N metal electrode 220 disposed below (i.e., on the bottom side of the figure) a semiconductor light emitting structure 230 and a current conducting layer 240, and a transparent substrate 250 disposed on the current conducting layer 240. When a current is applied to the P metal electrode 210 and the N metal electrode 220, a current flows through the current conducting layer 240, causing the semiconductor light emitting structure 230 to emit light. Finally, light passes through the transparent substrate 250, causing the light emitting diode to emit light.

[0003] FIG. 2 is a top view of the transparent substrate 250 and the current conducting layer 240 as seen from above in FIG. 1. The dotted rectangular frame on the left represents the opposing position 241 of the P metal electrode 210 in FIG. 1. The dotted rectangular frame on the right represents the opposing position 242 of the N metal electrode 220 in FIG. 1. As shown in FIGS. 1 and 2, when current is applied to the P metal electrode 210 and the N metal electrode 220, current flows in a substantially linear fashion between the opposing position 241 of the P metal electrode 210 and the opposing position 242 of the N metal electrode 220. Therefore, the light source is emitted from a narrow plane as shown in FIG. 2. Even if the design of the entire light-emitting surface is changed or the area of ​​the light-emitting surface is increased, the current flows along the shortest path, narrowing the light source surface and preventing improvement in light-emitting efficiency. Furthermore, because the current flows linearly between the opposing position 241 of the P metal electrode 210 and the opposing position 242 of the N metal electrode 220, the current density increases, which can cause problems such as heat generation, electrostatic discharge failure, and excessive leakage current.

[0004] Therefore, how to design a flip-chip type light emitting diode and its manufacturing method that can improve the above problems is a topic worth researching. Summary of the Invention

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a flip-chip type light-emitting diode that increases the light-emitting area and reduces the current density, and a method for manufacturing the same.

[0006] Another object of the present invention is to provide a flip-chip type light emitting diode and a manufacturing method thereof that effectively improves heat dissipation and enhances anti-static capability.

[0007] In order to achieve the above object, a method for manufacturing a flip-chip type light-emitting diode according to the present invention includes the steps of: providing a first substrate; performing an epitaxial process on the first substrate to form a semiconductor structure having, in that order from the first substrate, a first semiconductor epitaxial layer, a light-emitting layer, a second semiconductor epitaxial layer, and a current conducting layer, wherein a junction surface is formed in the current conducting layer to define a first electrode facing region and a second electrode facing region; performing a diffusion process on the junction surface using a diffusion material to form at least one path region with a high doping concentration in the current conducting layer; performing a bonding process to cover and bond a second substrate to the junction surface; and removing the first substrate, and forming, on the side of the semiconductor structure that was adjacent to the first substrate, a first electrode facing the first electrode facing region and electrically connected to the first semiconductor epitaxial layer, and a second electrode facing the second electrode facing region and electrically connected to the current conducting layer.

[0008] In an embodiment of the present invention, the at least one path region is located outside the shortest connecting path between the first electrode opposing region and the second electrode opposing region.

[0009] In an embodiment of the present invention, the path region is also formed as the shortest connection path between the first electrode opposing region and the second electrode opposing region.

[0010] In an embodiment of the present invention, each of the path regions is a rectangular region, a stripe region, a circular region, an elliptical region, a palisade region, a branch region, or a radial region.

[0011] In an embodiment of the present invention, the doping concentration in each of the path regions is 10 to 10 times the doping concentration of the current conducting layer in regions other than the path regions. 3 It's double.

[0012] In an embodiment of the invention, at least one bonding material is applied to the bonding surfaces before performing the bonding process.

[0013] In an embodiment of the invention, the diffusing material is beryllium, magnesium, zinc, or iron.

[0014] In an embodiment of the present invention, the diffusion material is the same type of material as the doping material of the current conducting layer.

[0015] In an embodiment of the present invention, the current conducting path formed in each of the path regions has a resistance value within a set range.

[0016] The present invention also provides a flip-chip type light-emitting diode manufactured using the above-described method for manufacturing a flip-chip type light-emitting diode.

[0017] Therefore, the method for manufacturing a flip-chip type light-emitting diode according to the present invention forms at least one path region with a high doping concentration at a predetermined position in the current conduction layer through a diffusion process. This allows current to easily pass through these path regions, preventing excessive current density concentration, and improving the light-emitting area and brightness of the flip-chip type light-emitting diode. Furthermore, the flip-chip type light-emitting diode manufactured by the method for manufacturing a flip-chip type light-emitting diode according to the present invention can have improved heat dissipation and antistatic capabilities. [Brief explanation of the drawings]

[0018] [Figure 1] Schematic diagram showing the structure of a conventional flip-chip type light-emitting diode [Figure 2]2 is a schematic diagram showing the conventional flip-chip light-emitting diode of FIG. 1 in an emitting state. [Figure 3] 1 is a flowchart showing a method for manufacturing a flip-chip type light-emitting diode according to the present invention. [Figure 4] 1 is a schematic diagram showing a structure corresponding to each step in a method for manufacturing a flip-chip type light-emitting diode according to the present invention. [Figure 5A] 1 is a schematic diagram illustrating a first embodiment of at least one pathway region of the present invention; [Figure 5B] Schematic diagram showing a second embodiment of at least one pathway region of the present invention. [Figure 5C] Schematic diagram showing a third embodiment of at least one pathway region of the present invention. [Figure 6] FIG. 1 is a schematic diagram showing a flip-chip type light-emitting diode manufactured by the method for manufacturing a flip-chip type light-emitting diode of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Each embodiment and example is merely illustrative and not limiting, and after reading this specification, a person skilled in the art can make other embodiments and examples without departing from the scope of the present invention. The features and advantages of the embodiments of the present invention will become more apparent from the following detailed description and the scope of the patent application.

[0020] The terms "one" or "an" are used herein to describe elements and components described herein for convenience and to give a general sense of the scope of the invention. Accordingly, unless otherwise indicated, such descriptions are understood to include one or at least one, and the singular also includes the plural.

[0021] As used herein, the ordinal terms "first" and "second" are primarily used to distinguish or refer to identical or similar components or structures, and do not necessarily imply a spatial or temporal ordering of these components or structures. It should be noted that in certain situations or configurations, the ordinal terms may be used interchangeably without affecting the practice of the present invention.

[0022] As used herein, the terms "comprise," "have," or other similar terms are intended to be non-exclusive inclusive. For example, a component or structure comprising multiple elements is not limited to only the elements listed herein, but may include other elements not expressly listed but inherent to the component or structure.

[0023] The following description will be given with reference to Figures 3 to 5A. Figure 3 is a flowchart showing a method for manufacturing a flip-chip type light-emitting diode according to the present invention. Figure 4 is a schematic diagram showing structures corresponding to each step in the method for manufacturing a flip-chip type light-emitting diode according to the present invention. Figure 5A is a schematic diagram showing a first embodiment of at least one path region according to the present invention. As shown in Figures 3 to 5A, the method for manufacturing a flip-chip type light-emitting diode according to the present invention includes the following steps:

[0024] Step S1: Provide a first substrate.

[0025] First, in the present invention, a first substrate 10 is used as a temporary substrate for the flip-chip type light-emitting diode 1 of the present invention. The first substrate 10 is mounted with components of the flip-chip type light-emitting diode 1. The first substrate 10 has a flat structure. In the embodiment of the present invention, the first substrate 10 is a gallium arsenide (GaAs) substrate. However, the first substrate 10 may be formed of other semiconductor materials or commonly used substrate materials, and the present invention is not limited thereto.

[0026] Step S2: An epitaxial process is performed to form a semiconductor structure on the first substrate. The semiconductor structure includes, in order from the first substrate, a first semiconductor epitaxial layer, a light emitting layer, a second semiconductor epitaxial layer, and a current conducting layer. A junction surface is formed in the current conducting layer, and a first electrode opposing region and a second electrode opposing region are defined in the current conducting layer.

[0027] After providing the first substrate 10 in step S1, the present invention then performs an epitaxial process on the first substrate 10 to form a semiconductor structure 20 on the first substrate 10. The semiconductor structure 20 is formed by epitaxially growing a first semiconductor epitaxial layer 21, a second semiconductor epitaxial layer 23, and a current conduction layer 24, in that order, on the first substrate 10. A light-emitting layer 22 is formed at the junction interface between the first semiconductor epitaxial layer 21 and the second semiconductor epitaxial layer 23. After conduction, the semiconductor structure 20 emits light due to the light-emitting layer 22. In an embodiment of the present invention, the first semiconductor epitaxial layer 21 is made of an N-type semiconductor material such as N-type aluminum indium gallium phosphide (AlGaInP). The light-emitting layer 22 is a multiple-quantum well (MQW) layer. The second semiconductor layer 23 is made of a P-type semiconductor material such as P-type aluminum indium gallium phosphide (AlGaInP). The current conducting layer 24 is made of P-type gallium phosphide (GaP) (e.g., doped with magnesium (Mg)). However, the materials of each layer of the semiconductor structure 20 are not limited to the aforementioned materials.

[0028] Because the current conducting layer 24 is stacked on the top of the semiconductor structure 20, the current conducting layer 24 has an exposed, large-area bonding surface 24a. In a subsequent manufacturing process, it is necessary to form a first electrode 40 and a second electrode 50 on the surface of the semiconductor structure 20 that was adjacent to one side of the first substrate 10. Therefore, a first electrode facing region A1 is formed on the bonding surface 24a of the current conducting layer 24, facing the first electrode 40 in the vertical direction. A second electrode facing region A2 is formed on the bonding surface 24a of the current conducting layer 24, facing the second electrode 50 in the vertical direction, facing the second electrode 50 in the vertical direction. In the embodiment of the present invention, the first electrode 40 and the second electrode 50 have a rectangular cross section parallel to the bonding surface 24a. Therefore, the first electrode facing region A1 and the second electrode facing region A2 are rectangular regions, but the present invention is not limited thereto.

[0029] Step S3: Perform a diffusion process on the junction surface using a diffusion material to form at least one path region with a high doping concentration in the current conducting layer.

[0030] After forming the semiconductor structure 20 in step S2, the present invention then performs a diffusion process on the current conducting layer 24. In the diffusion process, the diffusion material mainly diffuses at the junction surface 24a of the current conducting layer 24, and the diffusion material passes through the junction surface 24a to dope the current conducting layer 24, thereby changing the doping concentration of the current conducting layer 24. The diffusion material is of the same type as the doping material of the current conducting layer 24. In the embodiment of the present invention, since the material of the current conducting layer 24 is P-type gallium phosphide, the diffusion material is beryllium (Be), magnesium (Mg), zinc (Zn), or iron (Fe), but can also be other common P-type diffusion materials.

[0031] In the present invention, the region in the current conduction layer 24 where the doping concentration is changed is determined before the diffusion process is performed. As a result, after the diffusion process is performed, at least one path region P having a high doping concentration is formed in the current conduction layer 24. The path region P can be considered as a current conduction path in three-dimensional space. Current in a conventional flip-chip type light-emitting diode is mainly concentrated in the region linearly connected to both electrodes. The path region P is located outside the shortest connection path between the first electrode opposing region A1 and the second electrode opposing region A2 (on both sides of the shortest connection path). In other words, the path region P is located in a position where current is difficult to flow in a conventional flip-chip type light-emitting diode, thereby improving the problem of excessive current concentration in conventional flip-chip type light-emitting diodes. The high doping concentration in the path region P can reduce the resistance value of the original material, thereby forming a path in the path region P that allows current to easily flow. In an embodiment of the present invention, the doping concentration in each path region P is 10 to 10 times the doping concentration of the current conduction layer 24 in regions other than the path region P. 3 The doping concentration in the pathway region P is 1E+18 atoms / cm 3 That's all.

[0032] The length and shape of the path region P can be changed according to design requirements. In an embodiment of the present invention, the path region P is a rectangular region, a stripe region, a circular region, an elliptical region, a curved region, a palisade region, a branched region, or a radial region. In FIG. 5A, the path region P is a curved region, but the present invention is not limited thereto.

[0033] Furthermore, by design, the current conduction path formed in the path region P has a resistance value within a set range. That is, in the present invention, the resistance value of any one path region P is close to the resistance value of the adjacent path region P, and both are within the same set resistance value range. As a result, the resistances of any two path regions P are not very different, so current can flow through those path regions P, resulting in a better current dispersion effect and preventing excessive current concentration in a specific path region P.

[0034] As shown in FIG. 5A, the path region P consists of two curved regions located on either side of the shortest connecting path between the first electrode opposing region A1 and the second electrode opposing region A2. In conventional technology, the shortest connecting path between the first electrode opposing region A1 and the second electrode opposing region A2 is short, while the paths on either side of it are long and highly resistive, so current flows through the shortest connecting path. In the present invention, these path regions P are formed using a diffusion process. Each path region P has a resistance value within a set range (e.g., a resistance value within the above-mentioned set range that is the same as or close to that of the shortest connecting path). As a result, when current flows, it flows dispersedly through these path regions P and the shortest connecting path, increasing the area through which the current flows and improving the light-emitting area and brightness.

[0035] 5B is a schematic diagram illustrating a second embodiment of at least one path region of the present invention. As shown in FIG. 5B, in this embodiment, when the resistance values ​​of the path regions P located on both sides of the shortest connection path are much smaller than the resistance value of the shortest connection path, by forming a path region P on the shortest connection path between the first electrode opposing region A1 and the second electrode opposing region A2, the resistance values ​​of the path regions P on both sides and the resistance value of the shortest connection path can be made the same or similar.

[0036] 5C is a schematic diagram showing a third embodiment of at least one path region P of the present invention. As shown in FIG. 5C, in this embodiment, the path region P is a fence-shaped region. The distribution of the path regions P is such that they cover the entire area of ​​the current conducting layer 24 as much as possible, allowing the current to pass through a wider area, thereby increasing the light-emitting area.

[0037] Step S4: A bonding process is carried out to bond a second substrate to the bonding surface.

[0038] After performing the diffusion process in step S3, the present invention then performs a bonding process on the semiconductor structure 20, thereby covering and bonding the second substrate 30 to the bonding surface 24a of the current conducting layer 24. This completes the bonding between the second substrate 30 and the semiconductor structure 20. In the embodiment of the present invention, the second substrate 30 is a sapphire substrate, but the second substrate 30 may be made of other transparent materials, and the present invention is not limited thereto.

[0039] In order to smoothly bond the second substrate 30 to the bonding surface 24a of the current conducting layer 24, in an embodiment of the present invention, at least one bonding material M is applied to the bonding surface 24a before performing the bonding process. The bonding material M is a viscous gel-like material. For example, the bonding material M is a laminate of silicon dioxide (SiO2) and aluminum oxide (Al2O3), but the present invention is not limited thereto.

[0040] Step S5: The first substrate is removed, and a first electrode and a second electrode are formed on the side of the semiconductor structure that was adjacent to the first substrate. The first electrode faces the first electrode facing region and is electrically connected to the first semiconductor epitaxial layer. The second electrode faces the second electrode facing region and is electrically connected to the current conducting layer.

[0041] After performing the bonding process in step S4, the present invention removes the first substrate 10 adjacent to the semiconductor structure 20. Next, etching and electrode formation processes are performed on the side of the semiconductor structure 20 that was adjacent to the first substrate 10, thereby forming a first electrode 40 and a second electrode 50 on the semiconductor structure 20. The first electrode 40 is electrically connected to the first semiconductor epitaxial layer 21. The first electrode 40 faces the first electrode facing region A1. The second electrode 50 is electrically connected to the current conducting layer 24. The second electrode 50 faces the second electrode facing region A2. In this embodiment of the present invention, the first electrode 40 is an N-metal electrode, and the second electrode 50 is a P-metal electrode. The configuration of the first electrode 40 and the second electrode 50 is known as a common design for flip-chip light-emitting diodes, so a description thereof will be omitted.

[0042] Therefore, a flip-chip light-emitting diode 1 can be manufactured using the flip-chip light-emitting diode manufacturing method of the present invention. When power is supplied to the first electrode 40 and the second electrode 50 of the flip-chip light-emitting diode 1 of the present invention, current passes through the second electrode 50 and flows along the path region P in the current conducting layer 24, passes through the light-emitting layer 22 to emit light, and finally flows to the first electrode 40. Light emitted by the light-emitting layer 22 is emitted from the second substrate 30. These path regions P are located in positions where current flow is difficult in conventional technology (e.g., positions near the edge of the bonding surface 24a). This increases the overall light-emitting area of ​​the flip-chip light-emitting diode 1 of the present invention. This allows the current to be evenly distributed throughout the current conducting layer 24, reducing the current density and improving heat dissipation and antistatic capabilities.

[0043] The following description will be given with reference to FIGS. 3 to 6. FIG. 6 is a schematic diagram showing a flip-chip light-emitting diode manufactured by the method for manufacturing a flip-chip light-emitting diode of the present invention. As shown in FIGS. 3 to 6, the present invention also provides a flip-chip light-emitting diode 1 manufactured using the above-described method for manufacturing a flip-chip light-emitting diode. During the manufacturing process, the flip-chip light-emitting diode 1 of the present invention undergoes a diffusion process to form at least one path region P in the current conducting layer 24. The structure and function of the flip-chip light-emitting diode 1 of the present invention have been described in the description of the steps above, so they will not be repeated here.

[0044] The above-described embodiments are merely illustrative and are not intended to limit the embodiments or applications of the present application. Furthermore, while the above-described embodiments provide at least one illustrative example, it should be understood that numerous variations of the present invention are possible. Furthermore, the examples described herein are not intended to limit the scope, application, or configuration of the claims in any way. Rather, the above-described embodiments provide a guide for those skilled in the art to implement one or more of the embodiments. Furthermore, changes may be made in the function and arrangement of elements without departing from the scope of the claims, which include all known and foreseeable equivalents at the time of filing this patent application. [Explanation of symbols]

[0045] 1. Flip-chip light-emitting diode 10 First board 20 Semiconductor Structure 21 First semiconductor epitaxial layer 22 Light-emitting layer 23 Second semiconductor epitaxial layer 24 Current Conduction Layer 24a Joint surface 30 Second board 40 1st electrode 50 2nd electrode A1 1st electrode facing area A2 2nd electrode opposing area M Joining material P pathway region S1~S5 steps 200 Flip-chip light-emitting diode 210P metal electrode 220N metal electrode 230 Semiconductor Light Emitting Structure 240 Current Conduction Layer 241, 242 opposite positions 250 transparent substrate

Claims

1. A method for manufacturing a flip-chip type light-emitting diode, comprising the steps of: providing a first substrate; performing an epitaxial process to form a semiconductor structure on the first substrate, the semiconductor structure having, in order from the first substrate, a first semiconductor epitaxial layer, a light emitting layer, a second semiconductor epitaxial layer, and a current conducting layer, the current conducting layer having a junction surface formed therein to define a first electrode opposing region and a second electrode opposing region; performing a diffusion process at the junction surface using a diffusion material to form at least one path region with a high doping concentration in the current conducting layer; performing a bonding process to bond a second substrate to the bonding surface; removing the first substrate, and forming, on a side of the semiconductor structure that was adjacent to the first substrate, a first electrode facing the first electrode facing region and electrically connected to the first semiconductor epitaxial layer, and a second electrode facing the second electrode facing region and electrically connected to the current conducting layer; the pathway region is a current conduction pathway, The method for manufacturing a flip-chip type light-emitting diode, wherein the at least one path region includes the path regions located on both sides of a shortest connection path between the first electrode opposing region and the second electrode opposing region.

2. The method for manufacturing a flip-chip type light-emitting diode according to claim 1 , wherein the path region is also formed in the shortest connection path between the first electrode opposing region and the second electrode opposing region.

3. 2. The method for manufacturing a flip-chip type light-emitting diode according to claim 1, wherein each of the path regions is a rectangular region, a stripe region, a circular region, an elliptical region, a curved region, a fence region, a branch region, or a radial region.

4. The doping concentration in each of the path regions is 10 to 10 times the doping concentration of the current conducting layer in the regions other than the path regions. ３ 2. The method for manufacturing a flip-chip type light-emitting diode according to claim 1, wherein the number of steps is two.

5. 2. The method for manufacturing a flip-chip type light-emitting diode according to claim 1, wherein at least one bonding material is applied to the bonding surface before performing the bonding process.

6. 2. The method for manufacturing a flip-chip type light-emitting diode according to claim 1, wherein the diffusion material is beryllium, magnesium, zinc, or iron.

7. 2. The method for fabricating a flip-chip type light-emitting diode according to claim 1, wherein the diffusion material is the same as the doping material of the current conducting layer.

8. 2. The method for manufacturing a flip-chip type light emitting diode according to claim 1, wherein the current conduction path formed in each of the path regions has a resistance value within a set range.

9. A flip-chip type light-emitting diode manufactured by the method for manufacturing a flip-chip type light-emitting diode according to any one of claims 1 to 8.

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