Microstructure electrode for realizing limited-range infiltration of welding flux and preparation method of microstructure electrode

Abstract

The invention provides a microstructure electrode capable of realizing solder confinement infiltration and a preparation method thereof, a radial microgroove structure, an annular microgroove structure and a parallel line microgroove structure are sequentially engraved on the surface of the electrode to form functional combinations of different microstructures, and the microstructure electrode capable of realizing solder confinement infiltration is obtained. Fine machining of the microstructures on the surface of the electrode and functional combination of different microstructures are adopted, the wettability of the welding flux is enhanced through the radial microgroove structures in the center area, the spreading shape of the welding flux is controlled through the annular microgroove structures in the edge area, overflowing of the welding flux is restrained, and diffusion of the welding flux is guided through the parallel line microgroove structures in the connecting area. Therefore, through mutual combination and accurate processing of the microstructures with different functions, confinement infiltration of the welding flux on the surface of the electrode is realized, and the welding quality of the electronic element and the electrode is optimized.

Description

Technical Field

[0001] This invention belongs to the field of electronic component technology, specifically relating to a microstructure electrode for achieving solder confined wetting and its preparation method. Background Technology

[0002] With the rapid development of technology, electronic devices such as smartphones, wearable devices, and medical devices need to integrate more functions in a smaller space to improve product performance and functionality. Therefore, the miniaturization and high-density integration requirements of the electronics industry have led to the gradual replacement of traditional through-hole components with surface-mount components. To improve production efficiency, consistency, and repeatability, surface-mount components are typically mass-produced using automated placement equipment and reflow soldering. However, due to limitations in solder's ability to spread and adhere to the solid substrate surface—that is, solder wettability—solder may form spherical shapes that are difficult to spread, leading to defects such as cold solder joints and poor soldering. This affects the mechanical strength and reliability of the electrode-circuit board connection, or causes misalignment, overflow, or overspreading, resulting in solder bridging, creep, and other defects, creating undesigned electrical paths that can lead to short circuits. Existing surface-mount electronic components typically employ reflow soldering during the soldering process. In reflow soldering, the solder at the connection point between the electronic component and the substrate electrode melts and fills the joint. However, due to limitations in solder wettability, defects such as cold solder joints, poor soldering, or bridging can occur, leading to component detachment, open circuits, or short circuits. Therefore, there is an urgent need to develop a microstructure electrode that can improve solder wettability while effectively preventing solder overflow, and to develop compatible new processing and manufacturing techniques. Summary of the Invention

[0003] To address the aforementioned problems in existing technologies, this invention provides a microstructured electrode for confined solder wetting and its fabrication method. By combining microstructures with different functions and through precise fabrication, this invention enhances solder wettability on the electrode surface, controls solder spreading, prevents solder overflow, and improves welding strength, thereby optimizing the welding quality between electronic components and electrodes. The technical solution adopted in this invention is as follows: A method for fabricating a microstructure electrode that achieves solder confined wetting, comprising the following steps: (1) Electrode pretreatment The electrodes are pretreated to obtain pretreated electrodes. (2) Carve radial microgroove structures on the electrode surface On the pretreated electrode surface obtained in step (1), a radial microgroove structure is engraved; the radial microgroove is distributed in the center of the welding area, and has a radial structure with the center of the welding area as the center point; (3) Engraving annular microgroove structures on the electrode surface After carving the radial microgroove structure in step (2), the electrode surface is further carved with an annular microgroove structure. The annular microgroove structure is distributed on the edge of the radial microgroove structure except for the electrode connection area. The annular microgroove structure is a concentric circle structure with the center of the welding area as the center point. (4) Engraving parallel line microgroove structures on the electrode surface After engraving the annular microgroove structure in step (3), a parallel line microgroove structure is further engraved on the electrode surface; the parallel line microgroove structure is distributed in the middle of the two radial microgroove structures and is parallel to the line connecting the center points of the two radial microgroove structures, and the parallel line microgroove structure is in the form of a parallel line array structure. (5) Electrode post-treatment The electrode obtained in step (4) is post-processed to obtain the microstructure electrode that achieves solder confined wetting.

[0004] In step (1), the pretreatment of the electrode is to remove oil, impurities and oxide layer from the electrode surface by physical and / or chemical methods to obtain the pretreated electrode.

[0005] Preferably, in step (1), the pretreatment of the electrode is as follows: the electrode is immersed in detergent water, deionized water, ethanol and acetone in sequence for ultrasonic cleaning, and then dried to obtain the pretreated electrode.

[0006] The electrode is a metal electrode, which is one or a combination of several of the following: Au electrode, Ag electrode, Cu electrode, Fe electrode, Al electrode, Ni electrode, Sn electrode, and Ti electrode.

[0007] Preferably, the electrode layer is a copper electrode layer.

[0008] The shape of the electrode is adjusted according to application requirements, with the smallest electrode unit size not less than 0.1 × 0.1 mm. 2 .

[0009] The electrodes in this application are suitable for surface-mount thermoelectric devices, wherein the cross-sectional dimensions of the thermoelectric particles are 1.2 x 1.2 mm. 2 The interparticle spacing is 0.3 mm, therefore the electrode size used to connect the two particles is designed to be 1.2 x 1.7 mm. 2 .

[0010] In step (2), the specific pattern of the radial microgroove structure is as follows: The radial microgroove pattern is distributed in the center of the electrode welding area, and the area of ​​the radial microgroove structure accounts for 50-80% of the area of ​​the electrode welding area. Each microgroove extends outward from the center of the welding area. The width of the microgroove is 1-30 μm and the depth is 0.5-10 μm. The minimum distance between two adjacent microgrooves is 5-30 μm and the maximum distance is 20-50 μm. In order to control the microgroove spacing to meet the above requirements, different annular regions are divided according to the distance between the microgroove and the center point. The included angle between adjacent microgrooves in different annular regions is different, and the number of microgrooves is also different. The radial microgrooves are not processed in the part that exceeds the pattern area.

[0011] Preferably, in step (2), the specific pattern of the radial microgroove structure is as follows: Within a circular region with a radius of 100 μm, 30 microgrooves, each 100 μm in length, are arranged outwards from the center at a 12° angle; within a ring-shaped region with a radius between 100 μm and 200 μm, 60 microgrooves, each 100 μm in length, are arranged outwards from the center at a 6° angle; within a ring-shaped region with a radius between 200 μm and 300 μm, 90 microgrooves, each 100 μm in length, are arranged outwards from the center at a 4° angle; within a ring-shaped region with a radius between 300 μm and 400 μm, 120 microgrooves, each 100 μm in length, are arranged outwards from the center at a 3° angle; within a ring-shaped region with a radius between 400 μm and 500 μm... Within the domain, 150 microgrooves with a length of 100 μm are arranged outward from the center at an angle of 2.5°; within a ring-shaped region with a radius between 500 μm and 600 μm, 180 microgrooves with a length of 100 μm are arranged outward from the center at an angle of 2°, and then the microgrooves outside the square with a side length of 1 mm centered on the center are removed; within a ring-shaped region with a radius between 600 μm and 700 μm, 210 microgrooves with a length of 100 μm are arranged outward from the center at an angle of 1.7°, and then the microgrooves outside the square with a side length of 1 mm centered on the center are removed. The width of the microgrooves is 1~30 μm and the depth is 0.5~10 μm.

[0012] In step (3), for the left electrode, the annular microgroove structure is distributed on the upper, left and lower sides of the radial microgroove structure; for the right electrode, the annular microgroove structure is distributed on the upper, right and lower sides of the radial microgroove structure. Preferably, in step (3), for the left electrode, the annular microgroove structure is distributed on the upper, left, and lower sides of the radial microgroove structure area, and is distributed in the welding area other than the pattern of the radial microgroove structure; for the right electrode, the annular microgroove structure is distributed on the upper, right, and lower sides of the radial microgroove structure area, and is distributed in the welding area other than the pattern of the radial microgroove structure. The specific pattern of the annular microgroove structure is as follows: concentric circles are formed with the center point of the welding area as the center. The width of the microgroove is 1~30μm, the depth is 0.5~10μm, the radius difference between adjacent microgrooves is 10~50μm, and the part exceeding the pattern area is not processed into the annular microgroove.

[0013] Preferably, the specific pattern of the annular microgroove structure is as follows: taking the center point of the welding area as the center, starting from a radius of 510μm, concentric circles are added one by one with a radius difference of 10~30μm until the radius reaches 830μm. Then, the arc inside the square with a side length of 1mm centered on the center and the arc outside the square with a side length of 1.2mm centered on the center are removed. The width of the microgroove is 1~30μm and the depth is 0.5~10μm.

[0014] In step (4), the parallel line microgroove structure is distributed in the middle area of ​​two adjacent welding areas that need to be electrically connected, thereby connecting the two adjacent welding areas. The specific pattern of the parallel line microgroove structure is as follows: the line connecting the center points of two adjacent welding areas is parallel to the line connecting the center points of the two adjacent welding areas. The width of the microgroove is 1~30μm, the depth is 0.5~10μm, the spacing between adjacent microgrooves is 10~50μm, and the part exceeding the pattern area is not processed with the parallel line microgroove.

[0015] Preferably, in step (4), the specific pattern of the parallel line microgroove structure is as follows: the lower right corner of the left radial microgroove structure is connected to the lower left corner of the right radial microgroove structure, with a length of 300 μm, and parallel line array-type microgrooves are arranged with a line spacing of 10~30 μm. The width of the microgrooves is 1~30 μm and the depth is 0.5~10 μm.

[0016] In steps (2)-(4), the electrodes are processed by mechanical cutting, laser processing, chemical etching or photolithography. The minimum width of the microgroove is not less than 1 μm, the maximum depth is not more than 10 μm, and the minimum spacing is not less than 5 μm. Preferably, in steps (2)-(4), a femtosecond laser is used to etch the radial microgroove structure and the annular microgroove structure. The specific parameters are set as follows: the pulse frequency of the femtosecond laser is 50~200kHz, the pulse width is 200~500fs, the center wavelength is 200~300nm, and the beam waist radius is 5~10μm; the power of the femtosecond laser source is set to between 0.98~1.39W, and the scanning speed of the spot is set to 100~300 mm·s. -1 ; The engraving process involves performing 5 to 20 femtosecond laser line scans on the electrodes according to the pattern.

[0017] In step (5), the post-processing is to use physical and / or chemical methods to clean the electrode obtained in step (4) to remove oil, impurities and oxide layers from the electrode surface.

[0018] Preferably, in step (5), the post-processing is as follows: the electrode obtained in step (4) is sequentially immersed in deionized water, ethanol and acetone for ultrasonic cleaning, and then dried.

[0019] The method produces a microstructured electrode that achieves solder confined wetting.

[0020] The present invention has the following beneficial effects: This invention provides a method for fabricating a microstructured electrode that achieves confined solder wetting. The method involves pre-treating the electrode, then sequentially engraving radial microgrooves, annular microgrooves, and parallel-line microgrooves on the electrode surface, followed by post-treatment to obtain the microstructured electrode achieving confined solder wetting. This application employs precise machining of the electrode surface microstructures and accurate combination of different microstructures. The radial microgrooves in the center significantly improve solder wettability, the annular microgrooves in the surrounding area control the solder wetting shape and prevent overflow, and the parallel-line microgrooves in the connecting areas control the solder spreading direction. Simultaneously, the microstructures can also improve the surface roughness of the metal electrode, significantly enhancing welding stability. Therefore, this application, through the combination and precise machining of microstructures with different functions, achieves enhanced solder wettability on the electrode surface, controlled solder spreading, prevented solder overflow, and improved welding strength, thus optimizing the welding quality between electronic components and electrodes. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The diagram shows the fabrication process flow of the microstructure electrode that achieves solder confined wetting as described in Embodiment 1 of the present invention. Figure 2 Displayed as Figure 1 The enlarged view of the microstructure electrode that achieves solder confined wetting; wherein, (a) is an overall view of the microstructure electrode, and (b)-(f) are enlarged views of different regions in (a) respectively; Figure 3The images show wetting patterns of different microstructures and molten solder; (a) electrode without microstructure, (b) radial microgroove structure, (c) annular microgroove structure, and (d) parallel line microgroove structure. Figure 4 The image shows a patch thermoelectric device fabricated using the microstructure electrode obtained in Embodiment 1 of the present invention; wherein, (a) is an image of the thermoelectric device fabricated based on the microstructure electrode; (b) is an image of the reserved solder joint of the thermoelectric device; and (c) is an image of the patch solder joint of the internal electrode of the thermoelectric device. Figure 5 Other welding area patterns that can be used for the microstructure electrode described in this invention are shown; wherein, (a) is a rectangle, (b) is a square, (c) is a circle, and (d) is a hexagon. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] Unless otherwise specified, all reagents involved in the specific embodiments of this invention are commercially available products and can be purchased through commercial channels.

[0025] Example 1: This example provides a method for fabricating a microstructure electrode that achieves solder confined wetting. The process flow diagram is shown below. Figure 1 As shown, the specific steps include: (1) Electrode pretreatment The electrodes were pretreated by immersing them in detergent water, deionized water, ethanol and acetone in sequence for ultrasonic cleaning, and then drying them to obtain the pretreated electrodes. The electrode is used in a micro thermoelectric device. The electrode is fixed to an aluminum nitride substrate, and the size of a single electrode is 1.2 × 2.7 mm. 2 ; (2) Femtosecond laser parameter settings The pretreated electrode was placed under the femtosecond laser, with the laser focal plane coinciding with the electrode surface. A vacuum pump was then used to attach the electrode to the femtosecond laser processing platform. The femtosecond laser had a pulse frequency of 100 kHz, a pulse width of 290 fs, a center wavelength of 243 nm, and a beam waist radius of 7.5 μm. The power of the femtosecond laser source was set between 0.98 and 1.39 W, and the scanning speed of the laser spot was set to 200 mm / s. -1Aim the nitrogen gun at the electrode, turn on the switch to provide an atmosphere for electrode protection and to promptly remove metal particles generated during the processing.

[0026] (3) Carve radial microgroove structures on the electrode surface A radial microgroove structure is engraved on the surface of the pretreated electrode; the radial microgrooves are distributed in the center of the welding area, forming a radial structure with the center of the welding area as the center point; the specific pattern is (see...). Figure 2 As shown): Within a circular region with a radius of 100 μm, 30 microgrooves (R1, θ1, θ1) are arranged outward from the center at an angle of 12°. Each microgroove is 100 μm long. Figure 2 b) Within a ring-shaped region with a radius between 100 μm and 200 μm, 60 microgrooves, each 100 μm in length, are arranged outwards from the center at an angle of 6°; within a ring-shaped region with a radius between 200 μm and 300 μm, 90 microgrooves, each 100 μm in length, are arranged outwards from the center at an angle of 4° (R2-R1). Figure 2 c); Within a circular region with a radius between 300μm and 400μm, 120 microgrooves (R3-R2, R3-R4) with a length of 100μm are arranged outward from the center at an angle of 3°. Figure 2 d) Within a ring-shaped region with a radius between 400 μm and 500 μm, 150 microgrooves, each 100 μm long, are formed outwards from the center at an angle of 2.5°. Within a ring-shaped region with a radius between 500 μm and 600 μm, 180 microgrooves, each 100 μm long, are formed outwards from the center at an angle of 2°. Then, the microgrooves outside the 1 mm square centered on the center are removed. Within a ring-shaped region with a radius between 600 μm and 700 μm, 210 microgrooves, each 100 μm long, are formed outwards from the center at an angle of 1.7°. Then, the microgrooves outside the 1 mm square centered on the center are removed. The electrodes are then processed using a femtosecond laser line scan 10 times according to the above patterns.

[0027] (4) Engraving annular microgroove structures on the electrode surface After engraving the radial microgroove structure in step (2), a ring-shaped microgroove structure is further engraved on the electrode surface. The ring-shaped microgroove structure is distributed on the edge of the radial microgroove structure except for the electrode connection area. For the left electrode, the ring-shaped microgroove structure is distributed on the upper, left, and lower sides of the radial microgroove structure; for the right electrode, the ring-shaped microgroove structure is distributed on the upper, right, and lower sides of the radial microgroove structure. The ring-shaped microgroove structure is a concentric circle structure with the center of the welding area as the center point. The specific pattern of the annular microgroove structure is as follows: taking the center point of the welding area as the center, starting from a radius of 510 μm, with a radius difference of 20 μm ( Figure 2(e) Concentric circles are added one by one until the radius is 830 μm. Then, the arc inside the square with a side length of 1 mm centered on the circle and the arc outside the square with a side length of 1.2 mm centered on the circle are removed. The electrode is then processed by femtosecond laser line scanning 10 times according to the above pattern.

[0028] (5) Engraving parallel line microgroove structures on the electrode surface After engraving the annular microgroove structure in step (4), a parallel line microgroove structure is further engraved on the electrode surface; the parallel line microgroove structure is distributed in the middle of the two radial microgroove structures and is parallel to the line connecting the center points of the two radial microgroove structures, and the parallel line microgroove structure is in the form of a parallel line array structure. The specific pattern of the parallel line microgroove structure is as follows: 51 parallel line microgrooves are arranged with a length of 300 μm, connecting the lower right corner of the left radial microgroove structure to the lower left corner of the right radial microgroove structure, with a line spacing of 20 μm. Figure 2 f). The electrodes are processed by 10 femtosecond laser line scans according to the above pattern.

[0029] (6) Electrode post-treatment The electrode obtained in step (5) is post-processed, specifically by immersing the substrate in deionized water, ethanol, and acetone in sequence for ultrasonic cleaning, and then drying the substrate to obtain the microstructure electrode that achieves solder confined wetting. Figure 2 a).

[0030] As an alternative implementation, the microstructure electrode of the present invention can adopt other welding area patterns depending on the shape of the welding area, such as rectangles, squares, circles, hexagons, etc. Figure 5 As shown.

[0031] Depending on the application of the electrode, other metallic materials can be used, such as Au electrodes, Ag electrodes, Cu electrodes, Fe electrodes, Al electrodes, Ni electrodes, Sn electrodes, and Ti electrodes.

[0032] Depending on the processing requirements, other processing techniques can be used, such as mechanical cutting, laser processing, chemical etching, and photolithography, or one or more of these techniques.

[0033] Experimental Example 2: Performance testing of the microstructure electrode that achieves solder confined wetting obtained in Example 1.

[0034] The radial microgroove structure of the microstructure electrode described in this invention is beneficial for enhancing the wettability of solder on the surface of the metal electrode. For example... Figure 3 As shown, the wetting area of ​​the molten solder on the electrode surface with radial microgroove structure in (b) is larger than that on the electrode without microstructure in (a).

[0035] The annular microgroove structure of the microstructure electrode described in this invention is beneficial for controlling the shape of the solder after it has wetted the metal electrode surface, and can prevent solder overflow during the welding process. Figure 3 As shown, the wetting area of ​​the molten solder on the electrode surface with the annular microgroove structure in (c) is smaller than that on the electrode without the microstructure in (a), and the area along the annular microstructure is a regular circle.

[0036] The parallel-line microgroove structure of the microstructure electrode described in this invention is beneficial for controlling the flow direction of the solder, such as... Figure 3 As shown, the wetting area of ​​the electrode surface with parallel line microgroove structure in (d) is different from the circular shape of the electrode surface without microstructure in (a), and the parallel line direction is approximately rectangular with arc edges.

[0037] The microstructure combination of the electrodes described in this invention is advantageous in simultaneously enhancing the wettability of the solder on the surface of the metal electrode, controlling the wetting shape and flow direction of the solder, preventing solder overflow during the welding process, and greatly improving the welding quality between electronic devices and electrodes. Figure 4 The image shows a surface-mount thermoelectric device fabricated using the microstructure electrode described in Embodiment 1 of the present invention. It can be seen that there is no solder overflow at the reserved solder joints and the surface-mount welding points.

[0038] The method for fabricating a microstructured electrode with confined solder wetting as described in this invention involves pre-treating the electrode, then sequentially engraving radial microgroove structures, annular microgroove structures, and parallel line microgroove structures on the electrode surface, and finally post-treating the electrode to obtain the microstructured electrode with confined solder wetting. This application utilizes femtosecond lasers to achieve precise machining of the electrode surface microstructures and accurate combination of different microstructures. The radial microgroove structure at the center significantly improves solder wettability, the annular microgroove structure in the surrounding area controls the solder wetting shape and prevents overflow, and the parallel line microgroove structure in the connecting area controls the solder spreading direction. Simultaneously, the microstructures can also improve the surface roughness of the metal electrode, significantly enhancing welding stability. Therefore, this application, through the combination of microstructures with different functions and the precise machining of femtosecond lasers, achieves enhanced solder wettability on the electrode surface, controlled solder spreading, prevents solder overflow, and improves welding strength, thus optimizing the welding quality of electronic components and electrodes.

Claims

1. A method for fabricating a microstructure electrode that achieves solder confined wetting, characterized in that the steps include... include: (1) Electrode pretreatment The electrodes are pretreated to obtain pretreated electrodes. (2) Carve radial microgroove structures on the electrode surface On the surface of the pretreated electrode obtained in step (1), a radial microgroove structure is engraved; the radial microgroove is distributed in the center of the welding area, and the structure is radial with the center of the welding area as the center point; (3) Engraving annular microgroove structures on the electrode surface After carving the radial microgroove structure in step (2), the electrode surface is further carved with an annular microgroove structure. The annular microgroove structure is distributed on the edge of the radial microgroove structure except for the electrode connection area. The annular microgroove structure is a concentric circle structure with the center of the welding area as the center point. (4) Engraving parallel line microgroove structures on the electrode surface After engraving the annular microgroove structure in step (3), a parallel line microgroove structure is further engraved on the electrode surface; the parallel line microgroove structure is distributed in the middle of the two radial microgroove structures and is parallel to the line connecting the center points of the two radial microgroove structures, and the parallel line microgroove structure is in the form of a parallel line array structure. (5) Electrode post-treatment The electrode obtained in step (4) is post-processed to obtain the microstructure electrode that achieves solder confined wetting.

2. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, In step (1), the pretreatment of the electrode is to remove oil, impurities and oxide layer from the electrode surface by physical and / or chemical methods to obtain the pretreated electrode.

3. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, The electrode is a metal electrode, which is one or a combination of several of the following: Au electrode, Ag electrode, Cu electrode, Fe electrode, Al electrode, Ni electrode, Sn electrode, and Ti electrode.

4. The method for preparing a microstructure electrode for confined solder wetting according to claim 3, characterized in that, The shape of the electrode is adjusted according to application requirements, with the smallest electrode unit size not less than 0.1 × 0.1 mm. 2 .

5. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, In step (2), the specific pattern of the radial microgroove structure is as follows: The radial microgroove pattern is distributed in the center of the electrode welding area, and the area of ​​the radial microgroove structure accounts for 50-80% of the area of ​​the electrode welding area. Each microgroove extends outward from the center of the welding area. The width of the microgroove is 1-30 μm and the depth is 0.5-10 μm. The minimum distance between two adjacent microgrooves is 5-30 μm and the maximum distance is 20-50 μm. In order to control the microgroove spacing to meet the above requirements, different annular regions are divided according to the distance between the microgroove and the center point. The included angle between adjacent microgrooves in different annular regions is different, and the number of microgrooves is also different. The radial microgrooves are not processed in the part that exceeds the pattern area.

6. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, In step (3), for the left electrode, the annular microgroove structure is distributed on the upper, left and lower sides of the radial microgroove structure area, and is distributed in the welding area other than the pattern of the radial microgroove structure; for the right electrode, the annular microgroove structure is distributed on the upper, right and lower sides of the radial microgroove structure area, and is distributed in the welding area other than the pattern of the radial microgroove structure. The specific pattern of the annular microgroove structure is as follows: concentric circles are formed with the center point of the welding area as the center. The width of the microgroove is 1~30μm, the depth is 0.5~10μm, the radius difference between adjacent microgrooves is 10~50μm, and the part exceeding the pattern area is not processed into the annular microgroove.

7. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, In step (4), the parallel line microgroove structure is distributed in the middle area of ​​two adjacent welding areas that need to be electrically connected, thereby connecting the two adjacent welding areas. The specific pattern of the parallel line microgroove structure is as follows: the line connecting the center points of two adjacent welding areas is parallel to the line connecting the center points of the two adjacent welding areas. The width of the microgroove is 1~30μm, the depth is 0.5~10μm, the spacing between adjacent microgrooves is 10~50μm, and the part exceeding the pattern area is not processed with the parallel line microgroove.

8. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, In steps (2)-(4), the electrodes are processed by mechanical cutting, laser engraving, chemical etching or photolithography. The minimum width of the microgroove is not less than 1 μm, the maximum depth is not more than 10 μm, and the minimum spacing is not less than 5 μm.

9. The method for fabricating a microstructure electrode for confined solder wetting according to claim 1, characterized in that, In step (5), the post-processing is to use physical and / or chemical methods to clean the electrode obtained in step (4) to remove oil, impurities and oxide layers from the electrode surface.

10. A microstructure electrode that achieves solder confined wetting, prepared by the method according to any one of claims 1-9.

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