CN102800800A - Light-emitting diode device and production method thereof - Google Patents

Abstract

The invention discloses a light-emitting diode device and a manufacturing method thereof, which form a high Density-arranged light-emitting diodes without positive and negative metal electrodes can effectively take out the light emitted by the light-emitting layer, reduce the light absorption phenomenon of metal electrodes, increase light-emitting efficiency, reduce thermal resistance, prolong the service life of light-emitting diodes, and save packaging materials and simplified process flow.

Description

Light emitting diode device and manufacturing method thereof

technical field

The invention relates to a light emitting diode device and a manufacturing method thereof, in particular to a metal electrode-free light emitting diode device and a manufacturing method thereof.

Background technique

Light Emitting Diode (LED, Light Emitting Diode) is used in various fields due to its long life and low energy consumption. Devices, traffic signals, data storage devices, communication devices and lighting devices, etc.

Generally speaking, the existing light-emitting diode structure, as shown in Figure 1a, is mainly provided with a base A with a groove A1, a chip B is combined in the groove A1, and the chip B is connected to another through a connecting line C. A support D is connected, and finally the base A, the chip B, the connection line C and another support D are combined by injection molding of a light-transmitting layer E to complete the production of the light-emitting diode. The steps are relatively complicated.

However, when the above-mentioned traditional light-emitting diode is powered on, since the chip is combined in the concave cup of the base, the light emitted by the periphery and the bottom surface of the chip is blocked and reflected by the concave cup, so the chip only emits forward light. The light emitted by the LED cannot be seen from the backside. At present, there is also a method of directly connecting the chip to the printed circuit board with the help of surface mount technology (Surface Mount, SMT). After the circuit board is powered on, although the chip can emit light on five sides (front, back, left, right, and top), the bottom surface still cannot emit light.

In addition, the existing high-brightness white LED is made by mixing various colors of light. For example, red, green, and blue chips are combined to form white light through optical lenses, or purple or ultraviolet light is used to excite red, green and blue (RGB) phosphors to obtain white light, or blue light is used to excite yellow phosphors to obtain white light. Among them, the use of blue LEDs plus YAG yellow phosphor to produce white light is the most widely used. The disadvantage is that if the coating dose of the yellow phosphor is not controlled accurately during the packaging process, or conformal coating cannot be performed according to the shape of the chip, the outgoing light will appear bluish. or yellowish. Due to the strong fluidity of epoxy resin or silica gel, the encapsulation glue mixed with phosphor powder cannot form a uniform coating layer on the surface and surroundings of the chip during coating, which makes it difficult to guarantee the quality of white light LEDs. In order to overcome this defect, it is proposed that the glue mixed with phosphor powder be first cured into a film, and then pasted on the light-emitting chip. However, it cannot be guaranteed that the sides of the chip are evenly coated with phosphor. In addition, as the junction temperature of the chip continues to rise (in theory, the junction temperature of the blue-light chip can reach 300°C), but because the glue is difficult to withstand high temperatures, it will contact with the light-emitting chip to generate heat and deteriorate. The above packaging scheme is difficult to meet the requirements.

Contents of the invention

The main purpose of the present invention is to provide a light-emitting diode device and its manufacturing method, which is provided with a first conductive substrate and a second light-transmitting conductive structure on the bottom surface and the top surface of a light-emitting epitaxial structure including at least two light-emitting epitaxial units. , forming a high-density arrangement of light-emitting diodes without positive and negative metal electrodes, which can effectively extract the light emitted by the light-emitting layer, reduce the light absorption phenomenon of metal electrodes, increase light-emitting efficiency, reduce thermal resistance, and prolong the service life of light-emitting diodes. And save packaging materials and simplify the process flow.

The present invention mainly comprises the following manufacturing process steps:

1) Provide a growth substrate on which an integral light-emitting epitaxial layer is grown, and the light-emitting epitaxial layer sequentially includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer from bottom to top;

2) dividing the overall light-emitting epitaxial layer into several light-emitting epitaxial units arranged at intervals;

3) forming a second conductive substrate on the plurality of light-emitting epitaxial units arranged at intervals, for connecting to the positive pole of the power supply;

4) removing the growth substrate to expose the first semiconductor layer of the light-emitting epitaxial units arranged at intervals;

5) Forming a first light-transmitting conductive substrate structure on the first semiconductor layer of the light-emitting epitaxial units arranged at intervals, for connecting to the negative electrode of the power supply.

The light-emitting diode device includes:

A light emitting epitaxial structure comprising at least two light emitting epitaxial units, each light emitting epitaxial unit comprising a first semiconductor layer, a light emitting layer and a second semiconductor layer;

a first conductive substrate, formed on the first semiconductor layer, for connecting to a negative electrode of a power supply;

The second light-transmitting conductive substrate is formed on the second semiconductor layer and is used for connecting the positive electrode of the power supply.

Further, the growth substrate material can be selected from one of sapphire (Al ₂ O ₃ ), silicon carbide (SiC), silicon (Si), gallium nitride (GaN), gallium phosphide (GaP) or a combination thereof .

Further, the first conductive substrate is a light-transmitting substrate, thereby forming a light-emitting diode that emits light in all directions.

Further, the first conductive substrate is composed of a transparent substrate and a transparent conductive layer.

Further, the first conductive substrate is a reflective substrate.

Further, the first conductive substrate is composed of a heat dissipation substrate and a reflective layer.

Further, the second translucent conductive substrate is composed of a transparent substrate and a transparent conductive layer.

Further, the transparent substrate is selected from transparent glass, transparent flexible plastic or nano ceramics.

Further, the material of the transparent conductive layer may be one of indium tin oxide (ITO), zinc oxide (ZnO), In-doped ZnO, Al-doped ZnO, Ga-doped ZnO, or a combination thereof.

Further, the first conductive substrate contains fluorescent powder.

Further, the second translucent conductive substrate contains fluorescent powder.

Further, the reflective layer may be a distributed Bragg reflective layer, a metal reflective layer or an omnidirectional reflective layer.

Further, the material of the heat dissipation substrate may be one of silicon (Si) substrate, copper (Cu) substrate, aluminum (Al) substrate or a combination thereof.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. the

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In addition, the drawing data are descriptive summaries and are not drawn to scale.

FIG. 1 is a schematic cross-sectional view of a conventional light-emitting diode.

Fig. 2 is the cross-sectional schematic view of Japanese Patent Application No. 5-327026 light-emitting diode.

FIG. 3 is a schematic cross-sectional view of a light-emitting diode in Japanese Patent Application Laid-Open No. 2000-223752.

4 to 10 are schematic cross-sectional views of light-emitting diode devices manufactured in Example 1 of the present invention.

11 to 17 are schematic cross-sectional views of light-emitting diode devices manufactured in Example 2 of the present invention.

Fig. 18 is a schematic cross-sectional view of a light-emitting diode device manufactured in Example 3 of the present invention.

Explanation of component symbols in the figure:

100: Growth substrate; 101: First semiconductor layer; 102: Light emitting layer; 103: Second semiconductor layer; 104, 106: Transparent conductive layer; 105, 107: Transparent glass; 108: Positive pole of power supply; 109: Negative pole of power supply; 200 : Growth substrate; 201: First semiconductor layer; 202: Light emitting layer; 203: Second semiconductor layer; 204: Transparent conductive layer; 205: Transparent glass; 206: Reflective layer; 207: Heat dissipation substrate; 208: Phosphor powder; 209 : positive pole of power supply; 210: negative pole of power supply; 300: growth substrate; 301: first semiconductor layer; 302: light-emitting layer; 303: second semiconductor layer; 304, 306: transparent conductive layer; 305: transparent glass; 307: transparent flexible Plastic; 308, 309: fluorescent powder; 310: positive pole of power supply; 311: negative pole of power supply.

Detailed ways

The implementation of the present invention will be described in detail below in conjunction with the accompanying drawings and examples, so as to fully understand and implement the process of how to apply technical means to solve technical problems and achieve technical effects in the present invention.

Example 1

A light emitting diode device as shown in Figure 10, comprising: 3 LED epitaxial layers arranged at intervals, wherein the epitaxial layer includes a first semiconductor layer 101, a light emitting layer 102 and a second semiconductor layer 103; transparent glass 107 and transparent conductive The first transparent conductive glass structure composed of layer 106 is formed on the first semiconductor layer 101 for connecting to the negative electrode 109 of the power supply; the second transparent conductive glass structure composed of transparent glass 105 and transparent conductive layer 104 is formed on the first semiconductor layer 101 The above-mentioned second semiconductor layer 103 is used to connect to the positive electrode 108 of the power supply.

Specifically, the above light-emitting diode device includes: 3 LED epitaxial layers arranged at intervals, wherein the epitaxial layer includes an N-GaN layer 101, a light-emitting layer 102 and a P-GaN layer 103; a transparent glass 107 and a transparent ITO conductive layer 106 The first transparent conductive glass structure formed on the N-GaN layer 101 is used to connect the negative electrode 109 of the power supply; the second transparent conductive glass structure composed of transparent glass 105 and transparent ITO conductive layer 104 is formed on the On the P-GaN layer 103 , it is used to connect the positive electrode 108 of the power supply.

When the light-emitting diode is used to emit light, the first transparent conductive glass structure is connected to the negative electrode 109 of the power supply, and the second transparent conductive glass structure is connected to the positive electrode 108 of the power supply. The light-emitting layer 102 in the light-emitting diode emits light under the action of current. The light emitted from the light-emitting layer 102 can be transmitted through the surfaces of the first transparent conductive glass structure and the second transparent conductive glass structure, and can also be emitted from each side of the LED epitaxial layer, thereby realizing omni-directional light emission and improving luminescence. The external quantum efficiency of the diode improves the photoelectric performance of the light-emitting diode.

Figures 4 to 10 disclose the manufacturing method of the above-mentioned omnidirectional light-emitting diode, including the following steps:

As shown in FIG. 4 , first, a growth substrate 100 is provided, and the substrate 100 is formed of sapphire. In this embodiment, the substrate 100 is used to form a GaN-based blue light diode.

As shown in FIG. 5 , an entire epitaxial layer of LED is grown on a sapphire substrate 100 , and the epitaxial layers are N-GaN layer 101 , light-emitting layer 102 , and P-GaN layer 103 from bottom to top.

As shown in FIG. 6 , an ICP etching process is used to separate the entire epitaxial layer of the LED into three epitaxial layers arranged independently at intervals.

As shown in FIG. 7, a second transparent conductive glass structure is formed on the above three epitaxial layers arranged at intervals independently by using a bonding process, that is, the second transparent conductive glass structure is formed on the P-GaN layer 103, so that the The epitaxial layer originally on the sapphire substrate 100 is transferred to the second transparent conductive glass structure, and the second transparent conductive glass structure plays the role of supporting and fixing the epitaxial layers arranged at intervals independently, wherein the second transparent conductive glass structure is made of transparent glass 107 and transparent ITO conductive layer 106.

As shown in FIG. 8 , the above-mentioned sapphire substrate 100 is removed through a laser lift-off process, exposing the N-GaN layer 101 of the epitaxial layer arranged at intervals.

As shown in Figure 9, a bonding process is used to form a first transparent conductive glass structure on the N-GaN layer 101 of the epitaxial layer arranged at intervals to form a light emitting diode structure, wherein the first transparent conductive glass structure is made of transparent glass 107 and transparent ITO conductive layer 106.

As shown in FIG. 10 , the positive electrode 108 of the power supply is connected to the second transparent conductive glass structure, and the negative electrode 109 of the power supply is connected to the first transparent conductive glass structure, so as to form a conduction structure and make the light emitting diode structure work normally.

To sum up, this embodiment discloses a light emitting diode device and a manufacturing method thereof, which comprises a first transparent conductive glass structure and a second transparent conductive glass structure respectively on the bottom surface and the top surface Transparent conductive glass structure, when light is emitted from the light-emitting layer, it can exit from the first semiconductor layer on the bottom surface, the second semiconductor layer on the top surface, and the sides of the LED epitaxial layer, thereby improving the light-emitting efficiency, while the traditional light-emitting diodes emit light. The light from the first layer will be reflected when it passes through the first semiconductor layer to the silver glue at the bottom, and then passes through the first semiconductor layer, which will cause light loss. Most of the light is easily absorbed by multiple reflections inside the die, which is prone to Total reflection results in excessive light loss. In addition, this embodiment forms a light-emitting diode device without positive and negative metal electrodes, which can reduce the light absorption phenomenon of the metal electrodes and effectively increase the light extraction efficiency; it does not need to make metal electrodes, wire bonding, glue potting and other processes, so the process flow can be simplified. Save costs and improve production efficiency.

Example 2

A light emitting diode device as shown in Figure 17, comprising: 3 LED epitaxial layers arranged at intervals, wherein the epitaxial layer includes a first semiconductor layer 201, a light emitting layer 202 and a second semiconductor layer 203; a reflective layer 206 and a heat dissipation substrate The first substrate structure composed of 207 is formed on the first semiconductor layer 201 and is used to connect the negative electrode 210 of the power supply; the second substrate structure containing fluorescent powder composed of transparent glass 205 and transparent conductive layer 204 is formed on the said The second semiconductor layer 203 is used to connect to the positive electrode 209 of the power supply.

Specifically, the above light-emitting diode device includes: 3 LED epitaxial layers arranged at intervals, wherein the epitaxial layer includes an N-GaN layer 201, a light-emitting layer 202 and a P-GaN layer 203; 207, the first reflective and heat-dissipating substrate structure without phosphor is formed on the N-GaN layer 201, and is used to connect the negative electrode 210 of the power supply; the second substrate structure is a transparent conductive substrate structure containing phosphor 208, formed on The P-GaN layer 203 is used to connect the positive electrode 209 of the power supply, wherein the transparent conductive substrate structure is composed of a transparent glass 205 and a transparent ITO conductive layer 204 .

When the light-emitting diode is used to emit light, the first substrate structure without phosphor is connected to the negative electrode 210 of the power supply, and the second substrate structure containing phosphor is connected to the positive electrode 209 of the power supply. down glow. The light emitted from the self-luminous layer 202 directly passes through the second substrate structure containing phosphor powder on the top surface, and is excited by the phosphor powder to obtain white light, thereby avoiding the light absorption phenomenon of the metal electrode, effectively improving the light extraction efficiency, and improving the photoelectric performance of the light emitting diode. Secondly, the epitaxial layer of the LED is not in direct contact with the phosphor powder, which avoids possible failure due to heat dissipation, reduces thermal resistance, and prolongs the service life of the light-emitting diode; moreover, the light-emitting diode device produced by the present invention does not need to make metal electrodes, wires, etc. And other processes, which can simplify the process, save costs and improve production efficiency.

11 to 17 disclose the manufacturing method of the aforementioned light-emitting diode, including the following steps:

As shown in FIG. 11 , first, a growth substrate 200 is provided, and the substrate 200 is formed of silicon carbide. In this embodiment, the substrate 200 is used to form a GaN-based blue light diode.

As shown in FIG. 12 , the entire epitaxial layer of an LED is epitaxially grown on a silicon carbide substrate 200 , and the epitaxial layers are an N-GaN layer 201 , a light-emitting layer 202 , and a P-GaN layer 203 from bottom to top.

As shown in FIG. 13 , the overall epitaxial layer of the LED is separated into three epitaxial layers arranged at intervals independently by using an ICP etching process.

As shown in Figure 14, a bonding process is used to form a second transparent conductive substrate structure containing phosphor powder on the above three epitaxial layers arranged at intervals, that is, the second transparent conductive substrate structure containing phosphor powder is formed on P-GaN layer 203, so that the epitaxial layer originally on the silicon carbide substrate 200 is transferred to the second transparent conductive substrate structure containing phosphor, and the second transparent conductive substrate structure containing phosphor supports and fixes The function of the epitaxial layers arranged at intervals independently, wherein the second transparent conductive substrate structure is composed of transparent glass 205 and transparent ITO conductive layer 204 .

As shown in FIG. 15 , the above-mentioned silicon carbide substrate 200 is removed through a laser lift-off process, exposing the N-GaN layer 201 of the epitaxial layer arranged at intervals.

As shown in FIG. 16, a bonding process is used to form a first reflective heat dissipation substrate structure without phosphor powder on the N-GaN layer 201 of the epitaxial layer 201 arranged at intervals to form a light emitting diode structure. The first reflective heat dissipation substrate structure is composed of an omnidirectional reflective layer 206 and a Si heat dissipation substrate 207 .

As shown in FIG. 17 , the positive electrode 209 of the power supply is connected to the second substrate structure containing phosphor, and the negative electrode 210 of the power supply is connected to the first substrate structure not containing phosphor, so as to form a conduction structure, so that the light emitting diode structure normal work.

Example 3

    As shown in Figure 18, the light-emitting diode device is different from Embodiment 1 in that the number of LED epitaxial layers is 5, which can form a high-density arrangement; the first substrate structure is composed of a transparent conductive substrate structure containing phosphor powder, in which the transparent The conductive substrate structure is composed of transparent flexible plastic 307 and transparent ITO conductive layer 306 .

The manufacturing method of the above-mentioned light-emitting diode device differs from Embodiment 2 in that:

In order to improve the light conversion efficiency more effectively, the first substrate is a transparent conductive substrate structure containing phosphor powder, which can form a sandwich structure with the LED epitaxial layer and the second substrate structure containing phosphor powder, forming an all-round non-blocking positive and negative metal electrodes The white light-emitting diode can more effectively take out the light emitted by the light-emitting layer, reduce the light absorption phenomenon of the metal electrode, and increase the light efficiency, and does not need to make metal electrodes, wire bonding and other processes, which can save packaging materials, simplify the process flow, and improve production. In addition, the epitaxial layer of the LED is not in direct contact with the phosphor, which avoids possible failure due to heat dissipation, reduces thermal resistance, and prolongs the service life of the light-emitting diode.

Claims (12)

1. Light-emitting diode devices, including: A light emitting epitaxial structure comprising at least two light emitting epitaxial units, each light emitting epitaxial unit comprising a first semiconductor layer, a light emitting layer and a second semiconductor layer; a first conductive substrate, formed on the first semiconductor layer, for connecting to a negative electrode of a power supply; The second light-transmitting conductive substrate is formed on the second semiconductor layer and is used for connecting the positive electrode of the power supply. 2. The light-emitting diode device according to claim 1, wherein the first conductive substrate is a light-transmitting substrate, thereby forming a light-emitting diode that emits light in all directions. 3. The LED device according to claim 2, wherein the first conductive substrate is composed of a transparent substrate and a transparent conductive layer. 4. The LED device according to claim 1, wherein the first conductive substrate is a reflective substrate. 5. The light emitting diode device according to claim 4, wherein the first conductive substrate is composed of a heat dissipation substrate and a reflective layer. 6. The light emitting diode device according to claim 1, wherein the second transparent conductive substrate is composed of a transparent substrate and a transparent conductive layer. 7. The light emitting diode device according to claim 3 or 6, wherein the transparent substrate is selected from transparent glass, transparent flexible plastic or nano ceramics. 8. The light emitting diode device according to claim 3 or 6, characterized in that: the material of the transparent conductive layer is selected from indium tin oxide, zinc oxide, indium doped zinc oxide, aluminum doped zinc oxide, gallium doped One or a combination of zinc oxides. 9. The light emitting diode device according to claim 2 or 3, wherein the first conductive substrate contains phosphor. 10. The light emitting diode device according to claim 1, wherein the second transparent conductive substrate contains phosphor. 11. A method for manufacturing a light emitting diode device, comprising the steps of: 1) Provide a growth substrate on which an integral light-emitting epitaxial layer is grown, and the light-emitting epitaxial layer sequentially includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer from bottom to top; 2) dividing the overall light-emitting epitaxial layer into several light-emitting epitaxial units arranged at intervals; 3) forming a second conductive substrate on the plurality of light-emitting epitaxial units arranged at intervals, for connecting to the positive pole of the power supply; 4) removing the growth substrate to expose the first semiconductor layer of the light-emitting epitaxial units arranged at intervals; 5) Forming a first light-transmitting conductive substrate structure on the first semiconductor layer of the light-emitting epitaxial units arranged at intervals, for connecting to the negative electrode of the power supply. 12. The manufacturing method of a light emitting diode device according to claim 11, wherein the growth substrate material is selected from one of sapphire, silicon carbide, silicon, gallium nitride, gallium phosphide or a combination thereof.

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