CN102479886A - Method for manufacturing light-emitting diode with coarsened layer - Google Patents

Abstract

The invention relates to a manufacturing method of a light-emitting diode with a roughened layer, which mainly utilizes the control of the inclination angle of the light-emitting diode and carries out dry etching to etch a new roughened layer structure on a conductive layer of the light-emitting diode.

Description

Method for manufacturing a light emitting diode with a roughened layer

technical field

The invention relates to a method for manufacturing a light-emitting diode, in particular to a method for manufacturing a light-emitting diode with a roughened layer of grass-like nanostructure and high light extraction efficiency.

Background technique

Due to the rising awareness of environmental protection, everyone understands the importance of "energy saving and carbon reduction". Therefore, in the 21st century, light-emitting diodes with low power consumption and long life have become the new darling of the times. In terms of the application of light sources, the biggest difference between organic semiconductors and inorganic semiconductors is that the frequency distribution of light waves emitted by the former is wider, while the frequency distribution of the latter is very narrow, so the light color of organic semiconductors is softer. Organic light-emitting diodes can be made on plastic substrates because of their soft materials, so the products are very thin and easy to carry.

There are always various light sources to decorate in our life. In the office, desk lamps and indoor lamps are needed to ensure the quality of work and protect eyesight. In stores, signboards and various lights are needed to promote products and create various situations. Atmosphere, a soft light source is needed at home to increase the feeling of warmth and comfort, and even vehicles and signs need to be illuminated through lights. Not only that, TVs, movie screens, and monitors that provide us with entertainment and information all have a light source behind them.

Nowadays, human beings are inseparable from lights, and various light sources such as fluorescent lamps and incandescent bulbs are flooding our lives. Due to the rising awareness of environmental protection, everyone understands the importance of "energy saving and carbon reduction". At present, the efficiency of white LEDs will increase from 120 lumens per watt to 240 lumens per watt within two or three years, which will save the power generation of 150 nuclear power plants worldwide and reduce carbon dioxide emissions. Therefore, in the 21st century, light-emitting diodes with low power consumption and long life have become the new darling of the times.

There are many applications of light-emitting diodes, such as traffic signs, street lights, flashlights, and even car headlights. According to different materials, light emitting diodes can be divided into inorganic light emitting diodes and organic light emitting diodes. Inorganic light-emitting diodes use inorganic compounds such as gallium arsenide and gallium nitride as materials. These materials are first made p-type and n-type by doping, and then they are joined together to form a pn junction. Like other diodes, electrons and holes can be easily injected from n-type and p-type materials, and when electrons and holes meet and combine, energy will be released in the form of photons.

In 1997, a paper was published in Nichia Chemical Company of Japan, proposing a laser with InGaN semiconductor as the active region material, in which the InGaN multi-quantum well structure was grown on the ELOG (expitaxially laterally overgrown GaN) substrate. Not only has the performance of this laser been greatly improved, but its lifetime has exceeded 10,000 hours. This means that the achievements of Group III and V semiconductors are far superior to those of Group II and VI semiconductors, and many people will focus on Group III and V semiconductors in future research.

The early development of light-emitting diodes focused on improving the internal quantum efficiency. The main method was to improve the quality of the epitaxy and change the structure of the epitaxy, so that the electrical energy is not easily converted into heat energy, and then indirectly improve the luminous efficiency of the light-emitting diode, which can obtain about 90%. Theoretical internal quantum efficiency. However, such an internal quantum efficiency is almost close to the theoretical limit. Under such circumstances, it is impossible to increase the total light quantity of the component by simply increasing the internal quantum efficiency of the component. Therefore, the improvement of the light extraction rate of the component can be mainly divided into four directions. for:

1. Change the shape of the grain: the traditional light-emitting diode grain is made of a standard rectangular appearance, because the refractive index of general semiconductor materials is much different from that of epoxy resin (Epoxy), which makes the critical angle of total reflection at the interface small, The four cross-sections of the rectangle are parallel to each other, and the probability of photons leaving the semiconductor at the interface becomes smaller, so that the photons can only be fully reflected inside until they are completely absorbed, and the light is converted into heat, resulting in even worse luminous effects. Therefore, changing the shape of the light-emitting diode chip is an effective method to improve the luminous efficiency.

2. Waferbonding: Most of the light generated by light-emitting diodes will be absorbed by semiconductor materials and packaging materials after multiple total reflections. Therefore, if the light-absorbing GaAs is used as the substrate of the AlGaInP LED, the absorption loss inside the light-emitting diode will be increased, and the light extraction rate of the light-emitting diode will be greatly reduced. In order to reduce the substrate's absorption of the light emitted by the light-emitting diodes, some companies have proposed a transparent substrate bonding technology.

3. Surface roughness: By roughening the internal and external geometry of the LED, it destroys the total reflection of light inside the LED and improves the light-emitting efficiency of the LED.

4. Flip chip: For gallium nitride series materials using sapphire substrates, because the P pole and N pole electrodes must be made on the same side of the component, if the traditional packaging method is used, the light-emitting diode will be large. The upper light-emitting surface of part of the light-emitting area will lose most of the light due to the light blocking of the electrodes, and because the sapphire substrate is transparent, if the light can be taken out from the sapphire substrate, the light will increase greatly, so there is a flip-chip package. idea.

In view of the above problems, the present invention provides a method for manufacturing a light-emitting diode with a roughened layer. The manufacturing method of the present invention mainly utilizes controlling the inclination angle of the light-emitting diode and performing dry etching to etch a new roughened layer on the conductive layer of the light-emitting diode. The layer structure is used to improve the light extraction efficiency of the light emitting diode.

Contents of the invention

The purpose of the present invention is to provide a method for manufacturing a light emitting diode with a roughened layer. The manufacturing method of the present invention mainly utilizes controlling the inclination angle of the light emitting diode and performing dry etching to etch a new roughening layer on the conductive layer of the light emitting diode. Layer structure, the roughened layer of the present invention is a grass-like nanostructure, which is different from the conventional roughened layer structure, and the roughened layer of the present invention can make the light-emitting diode have higher light extraction efficiency.

The technical solution of the present invention: a method for manufacturing a light-emitting diode with a roughened layer, comprising:

Take a substrate;

depositing an epitaxial structure on the substrate;

plating a conductive layer on the epitaxial structure to form a light emitting diode;

controlling the tilt angle of the LED; and

Etching the conductive layer to form a roughened layer on the conductive layer;

Wherein the roughened layer is a grass-like nanostructure, and the grass-like nanostructure includes a plurality of corner pillars, each corner pillar includes a first hypotenuse and a second hypotenuse, the first hypotenuse and the second hypotenuse The angle between them is less than 90 degrees.

In the present invention, the substrate is a sapphire substrate.

In the present invention, wherein the epitaxial structure is gallium nitride is an epitaxial structure.

In the present invention, wherein depositing the epitaxial structure comprises:

Depositing a P-type semiconductor layer on the substrate;

Depositing a light-emitting layer on the P-type semiconductor layer: and

An N-type semiconductor layer is deposited on the light-emitting layer.

In the present invention, the material of the conductive layer is indium tin oxide.

In the present invention, the method of plating the conductive layer on the epitaxial structure is by evaporation.

In the present invention, dry etching is used to etch the conductive layer.

In the present invention, the dry etching is inductively coupled plasma etching.

In the present invention, the thickness of the roughened layer is smaller than the thickness of the conductive layer.

The beneficial effects of the present invention: a method for manufacturing a light-emitting diode with a roughened layer according to the present invention, the manufacturing method of the present invention mainly utilizes controlling the inclination angle of the light-emitting diode and performing dry etching on the conductive layer etching of the light-emitting diode A new roughened layer structure, the roughened layer of the present invention is a grass-like nanostructure, which is different from the known roughened layer structure, and the roughened layer of the present invention can make the light-emitting diode have a higher light extraction efficiency .

Description of drawings

Fig. 1: the schematic flow sheet of a preferred embodiment of the present invention;

FIG. 2A: a schematic diagram of step S10 of a preferred embodiment of the present invention;

FIG. 2B: a schematic diagram of step S12 of a preferred embodiment of the present invention;

Figure 2C: a schematic diagram of step S14 of a preferred embodiment of the present invention; and

FIG. 2D : a schematic diagram of step S18 in a preferred embodiment of the present invention.

[Description of drawing number comparison]

1 LEDs 10 Substrate

12 epitaxial structure 121 first semiconductor layer

123 Light-emitting layer 125 Second semiconductor layer

14 Conductive layer 141 Coarse layer

1411 Corner column 14111 first hypotenuse

14113 second hypotenuse

Detailed ways

In order to have a further understanding and understanding of the structural features of the present invention and the achieved effects, the preferred embodiments and accompanying drawings are used for a detailed description, as follows:

Please refer to FIG. 1 , which is a schematic flow chart of a preferred embodiment of the present invention. As shown in the figure, this embodiment provides a method for manufacturing a light emitting diode with a roughened layer. The manufacturing method of this embodiment mainly produces a roughened layer with a grass-like nanostructure. The roughened layer manufactured in this embodiment can effectively improve the light extraction efficiency of the light emitting diode.

Please also refer to FIG. 2A , which is a schematic diagram of step S10 in a preferred embodiment of the present invention. As shown in the figure, the method of manufacturing a light-emitting diode with a roughened layer in this embodiment is to perform step S10 first, and take a substrate 10, and the substrate 10 in this embodiment uses a sapphire substrate.

Please also refer to FIG. 2B , which is a schematic diagram of step S12 in a preferred embodiment of the present invention. As shown in the figure, step S12 is then performed to deposit an epitaxial structure 12 on the substrate 10. The epitaxial structure 12 in this embodiment is a gallium nitride epitaxial structure 12, and the epitaxial structure 12 includes a P-type semiconductor layer. 121. A light-emitting layer 123 and an N-type semiconductor layer 125. The P-type semiconductor layer 121 is first deposited on the substrate 10, then the light-emitting layer 123 is deposited on the P-type semiconductor layer 121, and finally the N-type semiconductor layer 125 is deposited on the light-emitting layer 123 superior.

Please also refer to FIG. 2C , which is a schematic diagram of step S14 in a preferred embodiment of the present invention. As shown in the figure, after the epitaxial structure 12 is deposited on the substrate 10, step S14 is performed to plate a conductive layer 14 on the epitaxial structure 12 to form a light emitting diode 1, and the material of the conductive layer 14 in this embodiment is indium oxide In addition, in this embodiment, the conductive layer 14 is plated on the epitaxial structure 12 by evaporation.

Then step S16 is executed to control the inclination angle of the light emitting diode 1 , mainly placing the light emitting diode 1 on a stage, and controlling the inclination angle of the light emitting diode 1 by changing the inclination angle of the stage. Please also refer to FIG. 2D , which is a schematic diagram of step S18 in a preferred embodiment of the present invention. As shown in the figure, step S18 is then performed to etch the conductive layer 14 to form a roughened layer 141 on the conductive layer 14 . The thickness of the roughened layer 141 is smaller than the thickness of the conductive layer 14 . In this embodiment, the roughening layer 141 is mainly formed by etching the conductive layer 14 by dry etching, wherein the dry etching is by inductively coupled plasma etching.

Referring again to FIG. 2D , FIG. 2D is a cross-sectional view of the light emitting diode 1 with the roughened layer 141 . It can be seen from FIG. 2D that the roughened layer 141 is a grass-like nanostructure, and the grass-like nanostructure includes a plurality of corner pillars 1411, and each corner pillar 1411 includes a first hypotenuse 14111 and a second hypotenuse 14113, and each corner pillar 1411 The angle between the first hypotenuse 14111 and the second hypotenuse 14113 is between 5 degrees and 30 degrees. When the slope of the first hypotenuse 14111 of each corner post 1411 is less than the slope of the second hypotenuse 14113 of each corner post 1411, the corner post 1411 will be inclined toward its second hypotenuse 14113 direction; When the slope of the first hypotenuse 14111 is greater than the slope of the second hypotenuse 14113 of each corner post 1411 , the corner post 1411 will incline toward the direction of the first hypotenuse 14111 .

It can be seen from the above that the present invention provides a method for manufacturing a light emitting diode with a roughened layer. The manufacturing method of the present invention mainly utilizes controlling the inclination angle of the light emitting diode and performing dry etching to etch a new roughened layer on the conductive layer of the light emitting diode. The roughened layer structure of the present invention is a grass-like nanostructure, which is different from the roughened layer structure of the prior art, and the roughened layer of the present invention can make the light-emitting diode have higher light extraction efficiency.

In summary, these are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. All equivalent changes and modifications are made in accordance with the shape, structure, characteristics and spirit described in the scope of the claims of the present invention. , should be included in the scope of the claims of the present invention.

Claims (9)

1. A method for manufacturing a light-emitting diode with a roughened layer, characterized in that it comprises: Take a substrate; depositing an epitaxial structure on the substrate; plating a conductive layer on the epitaxial structure to form a light emitting diode; controlling the tilt angle of the LED; and Etching the conductive layer to form a roughened layer on the conductive layer; Wherein the roughened layer is a grass-like nanostructure, and the grass-like nanostructure includes a plurality of corner pillars, each corner pillar includes a first hypotenuse and a second hypotenuse, the first hypotenuse and the second hypotenuse The angle between them is less than 90 degrees. 2. The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 1, wherein the substrate is a sapphire substrate. 3 . The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 1 , wherein the epitaxial structure is a gallium nitride epitaxial structure. 4 . 4. The method for manufacturing a light emitting diode with a roughened layer as claimed in claim 1, wherein depositing the epitaxial structure comprises: Depositing a P-type semiconductor layer on the substrate; Depositing a light-emitting layer on the P-type semiconductor layer: and An N-type semiconductor layer is deposited on the light-emitting layer. 5 . The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 1 , wherein the conductive layer is made of indium tin oxide. 6 . The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 1 , wherein plating the conductive layer on the epitaxial structure is by evaporation. 7 . 7. The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 1, wherein etching the conductive layer is performed by dry etching. 8. The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 6, wherein the dry etching is inductively coupled plasma etching. 9. The method of manufacturing a light emitting diode with a roughened layer as claimed in claim 1, wherein the thickness of the roughened layer is smaller than the thickness of the conductive layer.

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