CN104064632B - A kind of preparation method of light-emitting diodes pipe insulation layer - Google Patents

Abstract

The invention provides a method for preparing an insulating layer of a light-emitting diode, comprising: 1) forming a light-emitting epitaxial structure including an N-type layer, a quantum well layer, and a P-type layer on the front of a transparent substrate; 3) forming an N-type layer platform through photolithography and etching processes; 4) forming a metal layer structure covering the surface of the V-shaped groove and N-type layer platform; Filling the groove with photosensitive insulating material; 6) Exposing and developing from the back of the transparent substrate to remove the photosensitive insulating material not covered by the metal layer structure; 7) Reflowing and high temperature the photosensitive insulating material on the surface of the metal layer structure The carbonization treatment forms an insulating layer. The invention provides a novel groove-type electrode structure, and provides an effective method for preparing an insulating layer with simple steps, which is beneficial to cost saving and can effectively improve the performance of a light-emitting diode.

Description

A kind of preparation method of insulating layer of light-emitting diode

technical field

The invention relates to a preparation method of a light-emitting diode, in particular to a preparation method of an insulating layer of a light-emitting diode.

Background technique

As a new type of high-efficiency solid light source, semiconductor lighting has significant advantages such as long life, energy saving, environmental protection, and safety. It will become another leap in the history of human lighting after incandescent lamps and fluorescent lamps. The upgrading of the industry and other industries has huge economic and social benefits. Because of this, semiconductor lighting is generally regarded as one of the most promising emerging industries in the 21st century, and also one of the most important commanding heights in the field of optoelectronics in the next few years. Light-emitting diodes are made of III-IV compounds, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP (gallium arsenide phosphide) and other semiconductors, and its core is a PN junction. Therefore, it has the I-N characteristics of a general P-N junction, that is, forward conduction, reverse cut-off, and breakdown characteristics. In addition, under certain conditions, it also has luminous properties. Under forward voltage, electrons are injected into the P region from the N region, and holes are injected into the N region from the P region. Part of the minority carriers (minority carriers) entering the opposing region recombine with the majority carriers (many carriers) to emit light.

With the outbreak of the LED lamp market approaching, the research and development competition of LED packaging technology is also very fierce. At present, there are mainly three types of GaN-based LED packages: front-mount structure, flip-chip structure and vertical structure. At present, it is more mature that the group III nitride gallium nitride uses sapphire material as the substrate. Due to the insulation of the sapphire substrate, ordinary GaN-based LEDs adopt a front-mount structure. The light emitted by the active area of the front-mounted structure exits through the P-type GaN area and the transparent electrode. The structure is simple, and the manufacturing process is relatively mature. However, there are two obvious disadvantages of front-mount LEDs. First, the p- and n-electrodes of front-mount LEDs are on the same side of the LED, and the current must flow through the n-GaN layer laterally, resulting in current congestion and high local heat generation, which limits the driving current; second. , due to the poor thermal conductivity of the sapphire substrate, it seriously hinders the heat dissipation.

In order to solve the problem of heat dissipation, the American Lumileds Lighting Company invented the flip chip (Flipchip) technology. This method first prepares a large-sized LED chip suitable for eutectic welding, and at the same time prepares a silicon base plate of a corresponding size, and makes a gold conductive layer of the eutectic welding electrode and a lead-out conductive layer (ultrasonic gold wire ball soldering point) on it. Then, use the eutectic welding equipment to weld the large-size LED chip and the silicon base plate together. The heat dissipation effect of the installed structure has been greatly improved. However, the existing flip-chip structure is usually fixed on the silicon substrate by soldering, which often introduces more thermal resistance and reduces the heat dissipation efficiency of the LED chip. Moreover, for the LED chip with this structure, the P electrode and the N electrode are usually prepared on the same side of the LED chip, which often increases the difficulty of the flip-chip bonding process and the wire process, and it is difficult to achieve wafer-level manufacturing, which is likely to cause product defects. rate reduction.

The invention provides a trench-type light-emitting diode electrode structure, which can make P electrodes and N electrodes on both sides of the light-emitting diode, and provides a method that can effectively use photosensitive insulating materials to insulate the electrode structure.

Contents of the invention

In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method for preparing an insulating layer of a light-emitting diode, which is used to solve various problems in the prior art.

In order to achieve the above purpose and other related purposes, the present invention provides a method for preparing an insulating layer of a light-emitting diode, the preparation method at least including the following steps:

1) Provide a transparent substrate, and form a light-emitting epitaxial structure including at least an N-type layer, a quantum well layer, and a P-type layer on the front of the transparent substrate;

2) forming a V-shaped groove penetrating through the transparent substrate to a predetermined depth in the light-emitting epitaxial structure and the transparent substrate;

3) Etching the P-type layer, quantum well layer and part of the N-type layer on both sides of the V-shaped groove to form an N-type layer platform;

4) forming a metal layer structure covering the surface of the V-shaped groove and the N-type layer platform;

5) Filling the V-shaped groove with photosensitive insulating material;

6) Exposing and developing the above structure from the back of the transparent substrate, removing the photosensitive insulating material not covered by the metal layer structure, and retaining the photosensitive insulating material on the surface of the metal layer structure;

7) Perform reflow and high-temperature carbonization treatment on the photosensitive insulating material on the surface of the metal layer structure to complete the preparation of the insulating layer.

As a preferred solution of the method for preparing the insulating layer of a light-emitting diode of the present invention, the transparent substrate is a sapphire substrate, the N-type layer is an N-GaN layer, and the quantum well layer is a GaN/InGaN multi-quantum well layer , the P-type layer is a P-GaN layer.

As a preferred solution of the method for preparing the insulating layer of the light emitting diode of the present invention, step 2) adopts an inductively coupled plasma ICP etching technique to etch the V-shaped groove.

As a preferred solution of the method for preparing the insulating layer of the light emitting diode of the present invention, step 2) adopts an inductively coupled plasma ICP etching method to etch the V-shaped groove.

As a preferred solution of the method for preparing the insulating layer of the light-emitting diode of the present invention, step 2) adopts laser drilling technology to drill the V-shaped groove.

As a preferred solution of the method for preparing the insulating layer of the light emitting diode of the present invention, step 4) adopts a sputtering method or an electroplating method to form the metal layer structure.

As a preferred solution of the method for preparing the insulating layer of a light-emitting diode of the present invention, the structure of the metal layer is an alloy of two or more of Cr, Ti, Al, Ti, and Au.

As a preferred solution of the method for preparing the insulating layer of a light-emitting diode of the present invention, the photosensitive insulating material is a positive photoresist.

As a preferred solution of the method for preparing the insulating layer of the light-emitting diode of the present invention, step 5) fills the V-shaped groove with a photosensitive insulating material by using a spin coating method.

As a preferred solution of the preparation method of the light-emitting diode insulating layer of the present invention, the spin-coating method includes the following steps: a) coating a photosensitive insulating material on the surface of the above structure; b) rotating at a slow speed to make the photosensitive insulating material completely filling the V-groove; c) rotating rapidly to distribute the photosensitive insulating material evenly.

As mentioned above, the present invention provides a method for preparing an insulating layer of a light-emitting diode, including: 1) providing a transparent substrate, and forming a light-emitting epitaxial structure at least including an N-type layer, a quantum well layer, and a P-type layer on the front of the transparent substrate ; 2) Forming a V-shaped groove penetrating to a preset depth in the transparent substrate in the light-emitting epitaxial structure and the transparent substrate; 3) Etching the P-type layer and the quantum well layer on both sides of the V-shaped groove and part of the N-type layer to form an N-type layer platform; 4) Form a metal layer structure covering the surface of the V-shaped groove and the N-type layer platform; 5) Fill the V-shaped groove with a photosensitive insulating material; 6) From Exposing and developing the above structure on the back of the transparent substrate, removing the photosensitive insulating material that is not blocked by the metal layer structure, and retaining the photosensitive insulating material on the surface of the metal layer structure; 7) photosensitive insulation on the surface of the metal layer structure The material is subjected to reflow and high-temperature carbonization treatment to complete the preparation of the insulating layer. The invention provides a novel groove-type electrode structure, and provides a method for effectively preparing a photosensitive insulating layer with simple steps, which is beneficial to saving costs and improving the performance of a light-emitting diode.

Description of drawings

1 to 2 show the structural schematic diagrams presented in Step 1) of the method for preparing an insulating layer of a light-emitting diode according to the present invention.

FIG. 3 shows a schematic structural diagram presented in step 2) of the method for preparing an insulating layer of a light emitting diode according to the present invention.

FIG. 4 shows a schematic structural view presented in step 3) of the method for preparing an insulating layer of a light emitting diode according to the present invention.

FIG. 5 shows a schematic structural diagram presented in step 4) of the method for preparing an insulating layer of a light emitting diode according to the present invention.

FIG. 6 shows a schematic structural view presented in Step 5) of the method for preparing an insulating layer of a light emitting diode according to the present invention.

7 to 8 are schematic structural diagrams presented in step 6) of the method for preparing an insulating layer of a light-emitting diode according to the present invention.

Component designation description

101 transparent substrate

102 N-type layer

103 quantum well layer

104 P-type layer

105 V-groove

106 N-type layer platform

107 metal layer structure

108 photosensitive insulating material

109 insulating layer

detailed description

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

Please refer to Figure 1 to Figure 8. It should be noted that the diagrams provided in this embodiment are only schematically illustrating the basic idea of the present invention, and only the components related to the present invention are shown in the diagrams rather than the number, shape and shape of the components in actual implementation. Dimensional drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

As shown in Figures 1 to 8, this embodiment provides a method for preparing an insulating layer of a light-emitting diode, the preparation method at least including the following steps:

As shown in FIGS. 1-2 , step 1) is first performed, providing a transparent substrate 101 , and forming a light-emitting epitaxial structure at least including an N-type layer 102 , a quantum well layer 103 and a P-type layer 104 on the front of the transparent substrate 101 .

As an example, the transparent substrate 101 is a sapphire substrate, which may be a flat sapphire substrate or a patterned sapphire substrate. Of course, it may also be a transparent substrate 101 such as a Si substrate or a SiC substrate.

As an example, the light emitting epitaxial structure is formed by chemical vapor deposition.

As an example, the N-type layer 102 is an N-GaN layer, the quantum well layer 103 is a GaN/InGaN multi-quantum well layer 103 , and the P-type layer 104 is a P-GaN layer. Certainly, the light emitting epitaxial structure may also be GaAs (gallium arsenide) based, GaP (gallium phosphide) based, GaAsP (gallium arsenide phosphide) based and other light emitting epitaxial structures.

As shown in FIG. 3 , step 2) is then performed to form a V-shaped groove 105 penetrating through the transparent substrate 101 to a predetermined depth in the light-emitting epitaxial structure and the transparent substrate 101 .

As an example, firstly a photolithography mask is fabricated on the surface of the light-emitting epitaxial structure, then the V-shaped groove 105 is etched by an inductively coupled plasma ICP etching method, and finally the photolithography mask is removed.

As an example, the V-shaped groove is etched by an inductively coupled plasma ICP etching technique.

As an example, the V-shaped groove is drilled by laser drilling technology.

Preferably, the preset depth is 1/4˜1/2 of the thickness of the transparent substrate 101 .

As shown in FIG. 4 , proceed to step 3) to etch the P-type layer 104 on both sides of the V-shaped groove 105 , the quantum well layer 103 and part of the N-type layer 102 to form an N-type platform 106 .

As an example, the P-type layer 104 , the quantum well layer 103 and part of the N-type layer 102 are etched by an ICP etching method to form an N-type layer platform 106 for preparing N electrodes on both sides of the V-shaped groove 105 .

As shown in FIG. 5 , step 4) is then performed to form a metal layer structure 107 covering the surface of the V-shaped groove 105 and the N-type platform 106 .

As an example, the metal layer structure 107 is formed by sputtering or electroplating. In this embodiment, the metal layer structure 107 is formed by electroplating.

As an example, the metal layer structure 107 is an alloy of two or more of Cr, Ti, Al, Ti, Au. Certainly, the metal layer structure 107 may also be other metal materials such as W and Ag. It should be noted that the metal material should have a good blocking effect on ultraviolet rays, so as to facilitate subsequent processes.

As shown in FIG. 6 , proceed to step 5) to fill the V-shaped groove 105 with a photosensitive insulating material 108 .

As an example, the photosensitive insulating material 108 is positive photoresist.

As an example, the V-groove 105 is filled with a photosensitive insulating material 108 using a spin coating method.

As an example, since the V-shaped groove 105 has a large depth and a narrow bottom, it is difficult to fill it to the bottom of the V-shaped groove 105 using a common spin-coating process. Therefore, the present invention provides a spin coating of the photosensitive insulating material 108. Coating method, first, choose a thinner photoresist or adjust the photoresist to a thinner state and then spin coating, the spin coating method includes the following steps: a) coating a photosensitive insulating material 108 on the surface of the above structure; b) slow rotation to make the photosensitive insulating material 108 completely fill the V-shaped groove 105 ; c) fast rotation to make the photosensitive insulating material 108 evenly distributed. This method can effectively fill the V-shaped groove 105 with the photosensitive insulating material 108 and improve the performance of the light emitting diode. Moreover, compared with other insulating materials such as silicon dioxide or silicon nitride, the removal process of the photosensitive insulating material 108 is very simple, and there is no need to make a photolithography mask, and the removal of the photosensitive insulating material 108 is basically The light-emitting epitaxial structure does not cause any damage and has a very good insulating effect.

As shown in Figures 7 to 8, then proceed to step 6), exposing and developing the above structure from the back of the transparent substrate 101, removing the photosensitive insulating material 108 not covered by the metal layer structure 107, and retaining the metal A photosensitive insulating material 108 on the surface of the layer structure 107 .

As an example, the photosensitive insulating material 108 not shielded by the metal layer structure 107 can be simply removed after exposure by vertically incident ultraviolet light, and the photosensitive insulating material 108 on the surface of the metal layer structure 107 remains.

Finally, step 7) is performed to reflow and high-temperature carbonize the photosensitive insulating material 108 on the surface of the metal layer structure 107 to complete the preparation of the insulating layer 109 .

The photosensitive insulating material 108 after reflow and high-temperature carbonization treatment has better insulation effect and good mechanical strength, which can improve the performance of the final light-emitting diode.

In the subsequent process, the metal layer structure in the V-shaped groove can be exposed by thinning the transparent substrate, so that the electrode structure in which the P electrode and the N electrode are located on both sides of the light emitting diode can be realized.

In summary, the present invention provides a method for preparing an insulating layer of a light-emitting diode, including: 1) providing a transparent substrate, and forming a light-emitting epitaxial layer at least including an N-type layer, a quantum well layer, and a P-type layer on the front of the transparent substrate. structure; 2) forming a V-shaped groove penetrating to a preset depth in the transparent substrate in the light-emitting epitaxial structure and the transparent substrate; 3) etching the P-type layer and quantum well on both sides of the V-shaped groove Layer and part of the N-type layer form an N-type layer platform; 4) Form a metal layer structure covering the surface of the V-shaped groove and the N-type layer platform; 5) Fill the V-shaped groove with a photosensitive insulating material; 6) Exposing and developing the above structure from the back of the transparent substrate, removing the photosensitive insulating material that is not blocked by the metal layer structure, and retaining the photosensitive insulating material on the surface of the metal layer structure; 7) photosensitive to the surface of the metal layer structure The insulating material is subjected to reflow and high-temperature carbonization treatment to complete the preparation of the insulating layer. The invention provides a novel groove-type electrode structure, and provides a method for effectively preparing a photosensitive insulating layer with simple steps, which is beneficial to saving costs and improving the performance of a light-emitting diode. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (9)

1. a preparation method of light-emitting diode insulating layer, is characterized in that, described preparation method comprises the following steps at least: 1) A transparent substrate is provided, and a light-emitting epitaxial structure including at least an N-type layer, a quantum well layer, and a P-type layer is formed on the front of the transparent substrate; 2) forming a V-shaped groove penetrating through the transparent substrate to a predetermined depth in the light-emitting epitaxial structure and the transparent substrate; 3) etching the P-type layer on both sides of the V-shaped groove, the quantum well layer and part of the N-type layer to form an N-type layer platform; 4) forming a metal layer structure covering the surface of the V-shaped groove and the N-type layer platform; 5) Filling the V-shaped groove with a photosensitive insulating material; 6) Exposing and developing the above-mentioned structure from the back of the transparent substrate, removing the photosensitive insulating material that is not blocked by the metal layer structure, and retaining the photosensitive insulating material on the surface of the metal layer structure; 7) Perform reflow and high-temperature carbonization treatment on the photosensitive insulating material on the surface of the metal layer structure to complete the preparation of the insulating layer. 2. The method for preparing an insulating layer of a light-emitting diode according to claim 1, wherein the transparent substrate is a sapphire substrate, the N-type layer is an N-GaN layer, and the quantum well layer is GaN/InGaN The multi-quantum well layer, the P-type layer is a P-GaN layer. 3. The method for preparing an insulating layer of a light-emitting diode according to claim 1, characterized in that: step 2) using inductively coupled plasma (ICP) etching technology to etch the V-shaped groove. 4. The method for preparing an insulating layer of a light-emitting diode according to claim 1, characterized in that: step 2) using laser drilling technology to drill the V-shaped groove. 5 . The method for preparing an insulating layer of a light-emitting diode according to claim 1 , characterized in that: step 4) adopts a sputtering method or an electroplating method to form the metal layer structure. 6 . 6 . The method for preparing an insulating layer of a light-emitting diode according to claim 1 , wherein the structure of the metal layer is an alloy of two or more of Cr, Ti, Al, Ti, and Au. 7 . The method for preparing an insulating layer of a light emitting diode according to claim 1 , wherein the photosensitive insulating material is a positive photoresist. 8 . The method for preparing an insulating layer of a light-emitting diode according to claim 1 , characterized in that: step 5) filling the V-shaped groove with a photosensitive insulating material by using a spin coating method. 9. The method for preparing an insulating layer of a light-emitting diode according to claim 8, characterized in that: the spin coating method comprises the following steps: a) coating a photosensitive insulating material on the surface of the structure; b) rotating at a slow speed to make the The photosensitive insulating material completely fills the V-shaped groove; c) fast rotation makes the photosensitive insulating material evenly distributed.