Mini LED electrode and preparation method thereof, and LED chip

Abstract

The application provides a Mini LED electrode and a preparation method thereof and an LED chip, wherein the Mini LED electrode comprises an N electrode arranged on an epitaxial layer and a pad electrode arranged on the N electrode, the N electrode comprises a first electrode layer and a second electrode layer arranged on the first electrode layer; the first electrode layer comprises a first Au layer, an AuGeNi layer, a second Au layer and a first Pt layer which are sequentially stacked on the epitaxial layer, and the second electrode layer comprises a first Ti layer, a second Pt layer and a second Ti layer which are sequentially stacked on the first Pt layer; the LED chip electrode in the application is provided with two-layer electrode structures, the first-layer electrode is used for ensuring the performance of the electrode itself, the second-layer electrode is provided with a second Pt layer and is used for being connected with the pad electrode, so that when etching, the etching gas does not react with Pt when etching to the second Pt layer, and then film quality is not generated, and the problem that the voltage jumps in the actual production process of the Mini LED chip is solved.

Description

Technical Field

[0001] This invention relates to the field of Mini LED technology, and in particular to a Mini LED electrode, its preparation method, and an LED chip. Background Technology

[0002] The development trend of LEDs has progressed from early indoor and outdoor displays to high-density, high-contrast small-pitch displays, then to Mini flip-chip RGB displays, and finally to micron-level displays using MiCro LEDs. With the increasing demands for screen resolution, the development and research of Mini LEDs has been thrust into the spotlight in the past two years, becoming a very hot topic in the semiconductor industry.

[0003] In the actual mass production process of Mini LED, voltage fluctuations can occur. That is, after the chips that have passed the test are left to stand for a period of time, some chips will show high voltage after retesting. After some chips are re-electrode ESD, the voltage will return to normal. Such chips flow into the customer's hands and will show dim brightness and dead LEDs after being displayed, affecting product quality.

[0004] The reason for this problem is that in the manufacturing process of Mini LED electrodes, the conventional process requires etching the PSV passivation layer when preparing the pad electrode and the N electrode for electrical connection. This etching extends to the surface of the Au layer of the N electrode. Au easily absorbs moisture and reacts with some etching gases, forming some biofilms that act as barrier films. Often, as the chip is left in place for a longer period of time, these films gradually form. After ESD treatment, the films are broken down, and the voltage returns to normal. However, as time goes on, these films will regenerate, causing voltage fluctuations in the chip. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a Mini LED electrode and its preparation method, so as to solve the problem of voltage jumps that occur in the actual mass production process of Mini LED chips in the background art.

[0006] The present invention provides a Mini LED electrode, including an N electrode disposed on an epitaxial layer and a pad electrode disposed on the N electrode. The N electrode includes a first electrode layer and a second electrode layer disposed on the first electrode layer. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer and a first Pt layer sequentially stacked on the epitaxial layer. The second electrode layer includes a first Ti layer, a second Pt layer and a second Ti layer sequentially stacked on the first Pt layer.

[0007] The Mini LED electrode of this invention comprises an N-electrode disposed on an epitaxial wafer by sequentially arranging a first electrode layer and a second electrode layer from bottom to top. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer, arranged sequentially from bottom to top to ensure the original parameter performance of the N-electrode. The second electrode layer is composed of a first Ti layer, a second Pt layer, and another second Ti layer, arranged sequentially from bottom to top. During etching, when the second Pt layer is reached, the material properties of Pt prevent it from reacting with the etching gas and from absorbing moisture and reacting with the outside air, thus preventing the formation of a barrier film. This prevents voltage jumps in the Mini LED chip with the Mini LED electrode. Therefore, this invention solves the voltage jump problem that occurs in Mini LED chips during actual mass production in the prior art.

[0008] Preferably, the thickness ratio of the first electrode layer to the second electrode layer is 18-22:13-16.

[0009] Preferably, the thickness ratio of the first Au layer, the AuGeNi layer, the second Au layer, and the first Pt layer in the first electrode layer is 1-3:4-6:8-11:5-7, and the thickness ratio of the first Ti layer, the second Pt layer, and the second Ti layer in the second electrode layer is 1-3:3-6:1-3.

[0010] Preferably, the thickness of the first Au layer is 10nm-40nm, and the thickness of the first Ti layer is 25nm-100nm.

[0011] This invention also provides a method for preparing a Mini LED electrode, the method comprising:

[0012] N-electrode patterns were fabricated on the epitaxial layer using a negative resist peeling method;

[0013] The first electrode layer and the second electrode layer are sequentially deposited on the N-electrode pattern using electron beam evaporation.

[0014] A pad electrode is fabricated on the second electrode layer;

[0015] The process of depositing the first electrode layer includes:

[0016] The first Au layer, AuGeNi layer, second Au layer, and first Pt layer are deposited sequentially by vapor deposition;

[0017] The process of depositing the second electrode layer includes:

[0018] The first Ti layer, the second Pt layer, and the second Ti layer are deposited sequentially by vapor deposition.

[0019] Preferably, in the step of depositing the first electrode layer on the electrode pattern using electron beam evaporation:

[0020] The plating rate of the first Au layer is Evaporation thickness is The plating rate of the AuGeNi layer is Evaporation thickness is The second Au layer first adopts Evaporation rate Thickness, then use Evaporation coating thickness;

[0021] In the step of depositing the second electrode layer on the electrode pattern using electron beam evaporation:

[0022] The plating rate of the first Ti layer Evaporation thickness is The plating rate of the second Pt layer is Evaporation thickness is The plating rate of the second Ti layer is... Evaporation thickness is

[0023] The temperature required for the electronic vapor deposition method is 20℃-100℃.

[0024] Preferably, the step of further preparing the pad electrode on the electrode includes: applying negative adhesive, exposure, development, plasma gas treatment and coating on the second electrode layer;

[0025] The plasma gas treatment step includes: etching the second electrode layer with CH4 plasma gas to the second Pt layer.

[0026] Preferably, the step of etching the second electrode layer with CH4 plasma gas includes first etching with CH4, then rinsing away the reactants with N2 after etching, then etching with CH4 a second time, and finally rinsing away the reactants with N2.

[0027] Preferably, during the first etching, the etching power is 800W-2000W and the etching time is 800S-1200S; during the second etching, the etching power is 300W-700W and the etching time is 400S-600S. The pressure in the etching chamber during both etching processes is 2mt-10mt, the CH4 flow rate is 50sccm-150sccm, and the N2 flow rate is 600sccm-1200sccm.

[0028] Another aspect of the present invention provides an LED chip, including an epitaxial wafer and an electrode disposed on the epitaxial wafer, wherein the electrode is the aforementioned Mini LED electrode. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the N electrode on the Mini LED electrode in one embodiment of the present invention;

[0030] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0031] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0032] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Example 1

[0035] refer to Figure 1 This invention discloses a Mini LED electrode, including an N electrode disposed on an epitaxial layer and a pad electrode disposed on the N electrode. The N electrode includes a first electrode layer and a second electrode layer disposed on the first electrode layer. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer and a first Pt layer sequentially stacked on the epitaxial layer. The second electrode layer includes a first Ti layer, a second Pt layer and a second Ti layer sequentially stacked on the first Pt layer.

[0036] Specifically, the thickness ratio of the first electrode layer to the second electrode layer is 18-22:13-15. The second electrode layer is mainly used for etching, so it needs a certain thickness, and to ensure the total number of electrodes, the thickness of the second electrode layer is less than that of the first electrode layer. Preferably, the thickness ratio of the first electrode layer to the second electrode layer is 19-21:14-15, exemplarily 19:14, 19:15, 20:14, or 20:15, but not limited to these.

[0037] Specifically, the thickness ratio of the first Au layer, AuGeNi layer, second Au layer, and first Pt layer in the first electrode layer is 1-3:4-6:8-11:5-7. Preferably, in one embodiment of the present invention, the thickness ratio of the first Au layer, AuGeNi layer, second Au layer, and first Pt layer is 1-2:4-5:9-10:5-6, and exemplary ratios are 1:4:9:6, 2:5:9:5, 2:4:10:5, or 1:5:9:5.

[0038] Specifically, the thickness ratio of the first Ti layer, the second Pt layer, and the second Ti layer in the second electrode layer is 1-3:3-6:1-3. Preferably, in one embodiment of the present invention, the thickness ratio of the first Ti layer, the second Pt layer, and the second Ti layer in the second electrode layer is 1-2:4-5:1-2. Exemplary ratios are 1:4:1, 1:5:2, 2:5:1, or 1:5:1, but are not limited thereto.

[0039] Specifically, the thickness of the first Au layer is 10nm-40nm, and the thickness of the first Ti layer is 25nm-100nm. Preferably, in one embodiment of the present invention, the thickness of the first Au layer is 15nm-35nm, exemplarily 15nm, 20nm, 30nm or 35nm, but not limited thereto.

[0040] Preferably, in one embodiment of the present invention, the thickness of the first Ti layer is 30nm-90nm, exemplarily 30nm, 50nm, 70nm or 90nm, but not limited thereto.

[0041] It should be noted that a second electrode layer was added to replace the previous Au for dry etching. The original surface metal was a gold layer, which is prone to adsorbing oxide bonds on the surface and reacting to form a film, causing voltage jumps in the subsequent fabrication of MINI LED chips. Therefore, a second Pt layer was set as the surface metal. In order to increase the etching resistance of the electrode, a first Ti layer and a second Ti layer were added. Ti is also prone to adsorbing oxide bonds, so this time the etching reached the second Pt layer.

[0042] In summary, the Mini LED electrode in the above embodiments of the present invention comprises an N-electrode disposed on an epitaxial wafer by sequentially arranging a first electrode layer and a second electrode layer from bottom to top. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer, arranged sequentially from bottom to top to ensure the original parameter performance of the N-electrode. Furthermore, by sequentially arranging a first Ti layer, a second Pt layer, and another second Ti layer from bottom to top, during etching, when the second Pt layer is etched, the material properties of Pt prevent it from reacting with the etching gas, and the Pt layer itself does not absorb moisture or react with the outside air, thus preventing the formation of a barrier film. Consequently, the Mini LED chip with the Mini LED electrode does not experience voltage jumps. Therefore, the present invention solves the problem of voltage jumps that occur in Mini LED chips during actual mass production in the prior art.

[0043] This invention also discloses a method for preparing a Mini LED electrode, used to prepare the aforementioned Mini LED electrode, wherein the preparation method includes the following steps:

[0044] S1: First, a layer of negative adhesive is coated on the upper part of the epitaxial layer. The negative adhesive is soluble in the developer before exposure but insoluble after exposure. After exposure, the photosensitive part will remain on the surface of the epitaxial layer.

[0045] S2: Through exposure, the unexposed parts are dissolved in the developer, while the exposed parts of the negative photoresist will remain.

[0046] S3: The unexposed portion of the negative photoresist is quickly dissolved in the developer, while the exposure of the negative photoresist solution is slow. By controlling the development time, the pattern on the photomask is revealed.

[0047] S4: The unexposed negative photoresist is etched through plasma processing, leaving the pattern on the photomask, forming the first pattern.

[0048] S5: Remove contaminants such as oxides from the surface of the epitaxial layer by washing with water.

[0049] S6: The first electrode layer and the second electrode layer are sequentially deposited on the first pattern using an electronic vapor deposition method.

[0050] Specifically, in one embodiment of the present invention, the process of depositing the first electrode layer includes: sequentially depositing a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer; the process of depositing the second electrode layer includes: sequentially depositing a first Ti layer, a second Pt layer, and a second Ti layer. During the deposition process, the deposition rate of the first Au layer is... Evaporation thickness is The plating rate of the AuGeNi layer is Evaporation thickness is The second Au layer first uses Evaporation rate Thickness, then use Evaporation coating Thickness; Plating rate of the first Ti layer Evaporation thickness is The plating rate of the second Pt layer is Evaporation thickness is The plating rate of the second Ti layer is... Evaporation thickness is The required temperature for the electronic evaporation method is 20℃-100℃. Furthermore, since the second Au layer is relatively thick and has poor adhesion, when evaporating the second Au layer, a low plating rate is first used to improve the Au evaporation performance, followed by a second evaporation at a high plating rate to achieve the desired thickness and sufficient adhesion for the second Au layer.

[0051] S7: Prepare a pad electrode on the electrode.

[0052] Specifically, the steps for fabricating the pad electrode on the electrode include: applying negative adhesive, exposure, development, plasma gas treatment, and coating on the second electrode layer. These steps are essentially the same as those described above, except that the water washing step is omitted. Furthermore, the plasma gas treatment step includes a first etching using CH4, followed by rinsing away the reactants with N2, then a second etching using CH4, and finally rinsing away the reactants again with N2. The etching conditions are as follows: for the first etching, the etching power is 800W-2000W, and the etching time is 800S-1200S; for the second etching, the etching power is 300W-700W, and the etching time is 400S-600S. The etching chamber pressure is 2mt-10mt for both etching processes, the CH4 flow rate is 50sccm-150sccm for both processes, and the N2 flow rate is 600sccm-1200sccm for both processes. Specifically, by using CF4 as the primary etching gas, conventional chlorine etching was eliminated, avoiding reactions between chlorine and substances like Au. Furthermore, with the addition of a Ti / Pt / Ti structure, the etching process was improved to reach the Pt layer, effectively resolving the previous issue where etching gas reacted with Au to produce reactive substances that caused voltage spikes during subsequent use. The water rinsing process was also eliminated. Through optimized photolithography conditions and overdevelopment (increasing development time and reducing the amount of photoresist on the substrate), further oxidation of the electrode metal during subsequent rinsing was prevented, significantly reducing the voltage spike rate.

[0053] Another common testing procedure for chip inspection is to apply ESD to the chip before testing VF. The chip voltage is controlled by adjusting VF (1.6-2.4V). However, after ESD, the film is broken down, and the voltage will return to normal. Therefore, this measurement is not accurate enough and may lead to misjudgment. A VF (-0.04V-+0.04V) test can be added before ESD to test the voltage difference of the chip before ESD. Finally, qualified chips are screened by controlling the voltage difference.

[0054] The present invention will be further illustrated below with specific embodiments:

[0055] Example 1

[0056] This embodiment provides a Mini LED electrode, including an N electrode disposed on an epitaxial layer and a pad electrode disposed on the N electrode. The N electrode includes a first electrode layer and a second electrode layer disposed on the first electrode layer. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer sequentially stacked on the epitaxial layer. The second electrode layer includes a first Ti layer, a second Pt layer, and a second Ti layer sequentially stacked on the first Pt layer.

[0057] The thickness of the first Au layer is 15nm, the thickness of the AuGeNi layer is 75nm, the thickness of the second Au layer is 150nm, the thickness of the first Pt layer is 75nm, the thickness of the first Ti layer is 30nm, the thickness of the second Pt layer is 120nm, and the thickness of the second Ti layer is 30nm.

[0058] The method for preparing the Mini LED electrode in this embodiment includes the following steps:

[0059] (1): First, a layer of negative adhesive is coated on the upper part of the epitaxial layer. The negative adhesive is soluble in the developer before exposure but insoluble after exposure. After exposure, the photosensitive part will remain on the surface of the epitaxial layer.

[0060] (2): By exposure, the unexposed part is dissolved in the developer, and the exposed part of the negative adhesive will remain.

[0061] (3): The unexposed part of the negative adhesive is quickly dissolved in the developer, while the exposure of the negative adhesive solution is slow. By controlling the development time, the pattern on the photomask is revealed.

[0062] (4): The unexposed negative adhesive is etched by plasma treatment, leaving the pattern on the photomask, forming the first pattern.

[0063] (5): Remove contaminants such as oxides from the surface of the epitaxial layer by washing with water.

[0064] (6): The first electrode layer and the second electrode layer are sequentially deposited on the first pattern by electronic vapor deposition.

[0065] Specifically, in one embodiment of the present invention, the process of depositing the first electrode layer includes: sequentially depositing a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer; the process of depositing the second electrode layer includes: sequentially depositing a first Ti layer, a second Pt layer, and a second Ti layer. During the deposition process, the deposition rate of the first Au layer is... The plating rate of the AuGeNi layer is The second Au layer first uses The deposition rate is 20nm thick by vapor deposition, and then... The deposition rate is 55nm thick; the deposition rate of the first Ti layer is... The plating rate of the second Pt layer is The plating rate of the second Ti layer is... The required temperature for the electronic vapor deposition method is 60℃.

[0066] (7): Fabrication of pad electrodes on electrodes

[0067] Specifically, the steps for fabricating the pad electrode on the electrode include: applying negative adhesive, exposure, development, plasma gas treatment, and coating on the second electrode layer. These steps are essentially the same as those described above, except that the water washing step is omitted. Furthermore, the plasma gas treatment step includes a first etching with CH4, followed by rinsing away the reactants with N2, then a second etching with CH4, and finally rinsing away the reactants again with N2. The etching conditions are as follows: for the first etching, the etching power is 8000W and the etching time is 800s; for the second etching, the etching power is 300W and the etching time is 400s. The pressure in the etching chamber is 3mt for both etching processes, the CH4 flow rate is 60sccm, and the N2 flow rate is 700sccm.

[0068] Example 2

[0069] This embodiment provides a Mini LED electrode, including an N electrode disposed on an epitaxial layer and a pad electrode disposed on the N electrode. The N electrode includes a first electrode layer and a second electrode layer disposed on the first electrode layer. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer sequentially stacked on the epitaxial layer. The second electrode layer includes a first Ti layer, a second Pt layer, and a second Ti layer sequentially stacked on the first Pt layer.

[0070] The thickness of the first Au layer is 40 nm, the thickness of the AuGeNi layer is 200 nm, the thickness of the second Au layer is 400 nm, the thickness of the first Pt layer is 200 nm, the thickness of the first Ti layer is 60 nm, the thickness of the second Pt layer is 240 nm, and the thickness of the second Ti layer is 60 nm.

[0071] The method for preparing the Mini LED electrode in this embodiment includes the following steps:

[0072] (1): First, a layer of negative adhesive is coated on the upper part of the epitaxial layer. The negative adhesive is soluble in the developer before exposure but insoluble after exposure. After exposure, the photosensitive part will remain on the surface of the epitaxial layer.

[0073] (2): By exposure, the unexposed part is dissolved in the developer, and the exposed part of the negative adhesive will remain.

[0074] (3): The unexposed part of the negative adhesive is quickly dissolved in the developer, while the exposure of the negative adhesive solution is slow. By controlling the development time, the pattern on the photomask is revealed.

[0075] (4): The unexposed negative adhesive is etched by plasma treatment, leaving the pattern on the photomask, forming the first pattern.

[0076] (5): Remove contaminants such as oxides from the surface of the epitaxial layer by washing with water.

[0077] (6): The first electrode layer and the second electrode layer are sequentially deposited on the first pattern by electronic vapor deposition.

[0078] Specifically, in one embodiment of the present invention, the process of depositing the first electrode layer includes: sequentially depositing a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer; the process of depositing the second electrode layer includes: sequentially depositing a first Ti layer, a second Pt layer, and a second Ti layer. During the deposition process, the deposition rate of the first Au layer is... The plating rate of the AuGeNi layer is The second Au layer first uses The deposition rate is 100nm thick by vapor deposition, and then... The deposition rate is 300 nm thick; the deposition rate of the first Ti layer is... The plating rate of the second Pt layer is The plating rate of the second Ti layer is... The required temperature for the electronic vapor deposition method is 90℃.

[0079] (7): Prepare a pad electrode on the electrode.

[0080] Specifically, the steps for fabricating the pad electrodes on the electrode include: applying negative adhesive, exposure, development, plasma gas treatment, and coating on the second electrode layer. These steps are essentially the same as those described above, except that the water rinsing step is omitted. Furthermore, the plasma gas treatment step includes a first etching with CH4, followed by rinsing away the reactants with N2, then a second etching with CH4, and finally rinsing away the reactants again with N2. The etching conditions are as follows: for the first etching, the etching power is 1800W and the etching time is 1200s; for the second etching, the etching power is 700W and the etching time is 600s. The pressure in the etching chamber is 10mt for both etching processes, the CH4 flow rate is 150sccm, and the N2 flow rate is 1200sccm.

[0081] Example 3

[0082] This embodiment provides a Mini LED electrode, including an N electrode disposed on an epitaxial layer and a pad electrode disposed on the N electrode. The N electrode includes a first electrode layer and a second electrode layer disposed on the first electrode layer. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer sequentially stacked on the epitaxial layer. The second electrode layer includes a first Ti layer, a second Pt layer, and a second Ti layer sequentially stacked on the first Pt layer.

[0083] The thickness of the first Au layer is 20 nm, the thickness of the AuGeNi layer is 100 nm, the thickness of the second Au layer is 200 nm, the thickness of the first Pt layer is 100 nm, the thickness of the first Ti layer is 40 nm, the thickness of the second Pt layer is 160 nm, and the thickness of the second Ti layer is 40 nm.

[0084] The method for preparing the Mini LED electrode in this embodiment includes the following steps:

[0085] (1): First, a layer of negative adhesive is coated on the upper part of the epitaxial layer. The negative adhesive is soluble in the developer before exposure but insoluble after exposure. After exposure, the photosensitive part will remain on the surface of the epitaxial layer.

[0086] (2): By exposure, the unexposed part is dissolved in the developer, and the exposed part of the negative adhesive will remain.

[0087] (3): The unexposed part of the negative adhesive is quickly dissolved in the developer, while the exposure of the negative adhesive solution is slow. By controlling the development time, the pattern on the photomask is revealed.

[0088] (4): The unexposed negative adhesive is etched by plasma treatment, leaving the pattern on the photomask, forming the first pattern.

[0089] (5): Remove contaminants such as oxides from the surface of the epitaxial layer by washing with water.

[0090] (6): The first electrode layer and the second electrode layer are sequentially deposited on the first pattern by electronic vapor deposition.

[0091] Specifically, in one embodiment of the present invention, the process of depositing the first electrode layer includes: sequentially depositing a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer; the process of depositing the second electrode layer includes: sequentially depositing a first Ti layer, a second Pt layer, and a second Ti layer. During the deposition process, the deposition rate of the first Au layer is... The plating rate of the AuGeNi layer is The second Au layer first uses The deposition rate is 50nm thick by vapor deposition, and then... The deposition rate is 150 nm thick; the deposition rate of the first Ti layer is... The plating rate of the second Pt layer is The plating rate of the second Ti layer is... The required temperature for the electronic vapor deposition method is 60℃.

[0092] (7): Fabrication of pad electrodes on electrodes

[0093] Specifically, the steps for fabricating the pad electrode on the electrode include: applying negative adhesive, exposure, development, plasma gas treatment, and coating on the second electrode layer. These steps are essentially the same as those described above, except that the water washing step is omitted. Furthermore, the plasma gas treatment step includes a first etching with CH4, followed by rinsing away the reactants with N2, then a second etching with CH4, and finally rinsing away the reactants again with N2. The etching conditions are as follows: for the first etching, the etching power is 1500W and the etching time is 1000s; for the second etching, the etching power is 600W and the etching time is 550s. The pressure in the etching chamber is 6mt for both etching processes, the CH4 flow rate is 120sccm, and the N2 flow rate is 900sccm.

[0094] In summary, the Mini LED electrode fabrication method in the above embodiments of the present invention forms an N electrode on an epitaxial wafer by sequentially arranging a first electrode layer and a second electrode layer from bottom to top. The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer arranged sequentially from bottom to top to ensure the original parameter performance of the N electrode. By arranging the second electrode layer from bottom to top into a first Ti layer, a second Pt layer, and another second Ti layer, during etching, when etching reaches the second Pt layer, due to the material properties of Pt itself and by limiting the etching gas to only CH4, the second Pt layer will not react with the etching gas, and the Pt layer itself will not adsorb water vapor and react with the outside air, thus preventing the formation of a barrier film. Consequently, the Mini LED chip with Mini LED electrodes will not experience voltage jumps. Furthermore, the water washing process is eliminated, avoiding the situation where some substances are adsorbed on the Pt surface in the plasma coating machine, and then further diffused after rinsing, leading to further oxidation of the electrode metal. Therefore, the present invention solves the problem of voltage fluctuation in MINI LED chips during actual mass production in the background art.

[0095] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0096] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A Mini LED electrode, characterized in that, It includes an N electrode disposed on an epitaxial layer and a pad electrode disposed on the N electrode, wherein the N electrode includes a first electrode layer and a second electrode layer disposed on the first electrode layer; The first electrode layer includes a first Au layer, an AuGeNi layer, a second Au layer, and a first Pt layer sequentially stacked on the epitaxial layer, and the second electrode layer includes a first Ti layer, a second Pt layer, and a second Ti layer sequentially stacked on the first Pt layer. The thickness ratio of the first Au layer, the AuGeNi layer, the second Au layer, and the first Pt layer in the first electrode layer is 1-3:4-6:8-11:5-7, and the thickness ratio of the first Ti layer, the second Pt layer, and the second Ti layer in the second electrode layer is 1-3:3-6:1-3. The thickness of the first Au layer is 10 nm - 40 nm, and the thickness of the first Ti layer is 25 nm - 100 nm.

2. The Mini LED electrode according to claim 1, characterized in that, The thickness ratio of the first electrode layer to the second electrode layer is 18-22:13-16.

3. A method for fabricating a Mini LED electrode, characterized in that, The method for preparing the Mini LED electrode according to any one of claims 1 to 2, the method comprising: N-electrode patterns were fabricated on the epitaxial layer using a negative resist peeling method; The first electrode layer and the second electrode layer are sequentially deposited on the N-electrode pattern using electron beam evaporation. A pad electrode is fabricated on the second electrode layer; The process of depositing the first electrode layer includes: The first Au layer, AuGeNi layer, second Au layer, and first Pt layer are deposited sequentially by vapor deposition; The process of depositing the second electrode layer includes: The first Ti layer, the second Pt layer, and the second Ti layer are deposited sequentially by vapor deposition.

4. The method for preparing Mini LED electrodes according to claim 3, characterized in that, In the step of depositing the first electrode layer on the electrode pattern using electron beam evaporation: The first Au layer has a deposition rate of 1 Å / S - 3 Å / S and a deposition thickness of 0.2 KÅ - 0.4 KÅ. The AuGeNi layer has a deposition rate of 5 Å / S - 7 Å / S and a deposition thickness of 1 KÅ - 2 KÅ. The second Au layer is first deposited with a deposition rate of 4 Å / S - 6 Å / S to a thickness of 0.5 KÅ - 1 KÅ, and then deposited with a deposition rate of 7 Å / S - 9 Å / S to a thickness of 1.5 KÅ - 2 KÅ. In the step of depositing the second electrode layer on the electrode pattern using electron beam evaporation: The first Ti layer has a plating rate of 1 Å / S - 3 Å / S and a evaporation thickness of 0.5 KÅ - 1 KÅ; the second Pt layer has a plating rate of 1 Å / S - 3 Å / S and a evaporation thickness of 2 KÅ - 4 KÅ; the second Ti layer has a plating rate of 1 Å / S - 3 Å / S and a evaporation thickness of 0.5 KÅ - 1 KÅ. The temperature required for the electronic vapor deposition method is 20℃-100℃.

5. The method for preparing a Mini LED electrode according to claim 3, characterized in that, The step of preparing the pad electrode on the second electrode layer includes: applying negative adhesive, exposure, development, plasma gas treatment and coating on the second electrode layer; The plasma gas treatment step includes: etching the second electrode layer with CH4 plasma gas to the second Pt layer.

6. The method for preparing a Mini LED electrode according to claim 5, characterized in that, The step of etching the second electrode layer with CH4 plasma gas includes first etching with CH4, then rinsing away the reactants with N2 after etching, then etching with CH4 a second time, and finally rinsing away the reactants with N2.

7. The method for preparing a Mini LED electrode according to claim 6, characterized in that, During the first etching, the etching power is 800W-2000W and the etching time is 800S-1200S; during the second etching, the etching power is 300W-700W and the etching time is 400S-600S. The pressure in the etching chamber during both etching processes is 2mt-10mt, the flow rate of CH4 is 50 sccm-150 sccm, and the flow rate of N2 is 600 sccm-1200 sccm.

8. An LED chip, comprising an epitaxial wafer and electrodes disposed on the epitaxial wafer, characterized in that, The electrode is the Mini LED electrode according to any one of claims 1 to 2.

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