PCB hole metallization method based on suppressing the effect of leakage current

Abstract

This disclosure provides a PCB hole metallization method based on suppressing the effects of leakage current. The PCB hole metallization method based on suppressing the effects of leakage current includes: hole cleaning treatment for cleaning grease from the PCB board surface; micro-etching treatment for removing oxides from the copper surface of the PCB board and etching the copper surface; wherein a micro-etching grounding conductor is placed inside the micro-etching tank, and if leakage current occurs, the micro-etching grounding conductor absorbs the charge of the chemicals in the micro-etching tank, allowing the micro-etching grounding conductor to guide the charge of the chemicals in the micro-etching tank to a grounding support; pre-immersion treatment for forming a protective film on the hole walls and surface of the PCB board; activation treatment for adhering palladium colloid to the hole walls of the PCB board; acceleration treatment for removing the tin colloid layer on the PCB board surface and inside the holes, exposing the palladium colloid layer; and copper plating treatment for forming a copper layer on the hole walls of the PCB board. In this way, the portion of the micro-etching grounding assembly immersed in the micro-etching tank has strong corrosion resistance, extending the service life of the grounding treatment.

Description

Technical Field

[0001] This disclosure relates to the technical field of PCB boards, and in particular to a PCB hole metallization method based on suppressing the effects of leakage current. Background Technology

[0002] Plating copper, also known as plated-through-hole (PTH), connects the conductors between layers of double-sided or multi-layer circuit boards. It utilizes chemical deposition to deposit a thin layer of chemical copper onto the hole walls after drilling, providing conductivity for subsequent electroplating. The plating copper process is as follows: Resin removal → Hole preparation → Micro-etching → Pre-dip → Activation → Acceleration → Plating copper. The resin removal stage primarily removes residual resin from the holes caused by drilling, preventing ICD separation in multi-layer boards. Hole preparation cleans the board surface of grease, adjusting the hole walls from a negative charge to a positive charge. Micro-etching removes oxides from the copper surface and roughens it. Pre-dip prevents acidic substances and moisture from entering the activation tank and contaminating the solution. Activation allows tin-palladium colloids to adhere to the hole walls. Acceleration removes the tin colloid layer from the board surface and inside the holes, exposing the palladium colloid layer. Chemical copper plating uses formaldehyde as a reducing agent and palladium as a catalyst, reducing copper ions to metallic copper in an alkaline solution, which then adheres to the hole walls.

[0003] The quality of the copper plating directly affects the functionality of the final product, specifically whether the holes can conduct electricity. The quality of the copper plating is directly reflected in the backlight level (industry requirement ≥9). During the copper plating process, the chemical tanks are equipped with appropriate facilities, including vibration, ultrasonic, and oscillation mechanisms, to facilitate the flow of the plating solution.

[0004] Many factors can affect the backlight performance of electroless copper plating, such as poor hole preparation, poor activation, and insufficient copper plating activity. Another less noticeable factor is leakage from surrounding facilities like vibration and ultrasonic sources in the electroless copper plating solution tank. When these facilities leak, the current can enter the solution tank through the stainless steel copper plating frame. This leakage primarily affects the area between the hole preparation tank and the electroless copper plating tank. Because the chemical copper plating process involves chemical reactions and electrical charges, leakage from the surrounding facilities can affect these reactions. The leakage is sometimes difficult to detect because it occurs intermittently. Therefore, to prevent leakage from negatively impacting the backlight performance, the solution tank should be grounded.

[0005] The copper plating process involves strong acids and alkalis. For example, the micro-etching tank is made of sodium persulfate and 3-5% sulfuric acid, which can react with common metals such as copper. The activation tank contains about 5% hydrochloric acid, and the copper and iron ion content must be strictly controlled. Copper, iron, and even 304 stainless steel will be corroded, and copper and iron ions will be generated to contaminate the activation tank. The copper annealing tank contains a strongly alkaline environment with sodium hydroxide during production, but sulfuric acid and hydrogen peroxide are used to nitrate copper every few days after the tank is emptied. The nitrification solution is a strong acid and a strong oxidant, so the grounding wire from the pre-treatment tank to the copper annealing tank must be corrosion-resistant and will not contaminate the chemical tank, especially the activation tank.

[0006] In related technologies, one end of the grounding wire is exposed with copper wire and placed in a chemical tank, while the other end of the grounding wire is exposed with copper wire and tied to the surrounding ground support. However, due to the poor corrosion resistance of copper wire, the grounding wire fails quickly, meaning the grounding treatment fails quickly, usually within half a month or even less than a week. Summary of the Invention

[0007] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a PCB hole metallization method based on suppressing the effects of leakage current.

[0008] The purpose of this disclosure is achieved through the following technical solution:

[0009] A PCB hole metallization method based on suppressing leakage current effects involves metallizing the holes using a copper plating line. The copper plating line includes a floor support, a hole-forming cylinder, a micro-etching cylinder, a pre-dip cylinder, an activation cylinder, an acceleration cylinder, a copper-melting cylinder, and a copper plating frame. The hole-forming cylinder, the micro-etching cylinder, the pre-dip cylinder, the acceleration cylinder, and the copper-melting cylinder are sequentially arranged on the floor support. The copper plating frame is used to sequentially immerse the PCB board into the hole-forming cylinder, the micro-etching cylinder, the pre-dip cylinder, the acceleration cylinder, and the copper-melting cylinder.

[0010] The copper plating wire also includes a micro-etching grounding assembly, which includes a micro-etching grounding conductor, a micro-etching grounding wire, and a first polymethyl methacrylate (PMMA) cured body. The micro-etching grounding conductor is disposed in the chemical solution of the micro-etching tank. One end of the micro-etching grounding wire is electrically connected to the micro-etching grounding conductor, and the other end of the micro-etching grounding wire is electrically connected to the floor support. The first PMMA cured body is wrapped and connected to one end of the micro-etching grounding wire. The micro-etching grounding conductor is made of 316 stainless steel.

[0011] The PCB hole metallization method based on suppressing leakage current includes:

[0012] Hole cleaning process is used to clean the grease from the surface of the PCB board;

[0013] Micro-etching is used to remove oxides from the copper surface of the PCB board and etch the copper surface of the PCB board; wherein, the micro-etching grounding conductor is placed in the chemical solution of the micro-etching tank. If there is leakage, the micro-etching grounding conductor is used to absorb the charge of the chemical solution in the micro-etching tank, so that the micro-etching grounding wire is used to guide the charge of the chemical solution in the micro-etching tank to the floor support.

[0014] Pre-impregnation treatment is used to form a protective film on the hole walls and surface of the PCB board;

[0015] Activation treatment is used to allow palladium colloid to adhere to the hole walls of the PCB board;

[0016] Accelerated processing is used to remove the tin colloid layer from the surface and holes of the PCB board, exposing the palladium colloid layer.

[0017] Copper plating is used to form a copper layer on the hole walls of the PCB board.

[0018] In some embodiments, the micro-etching grounding conductor is disposed at the bottom of the micro-etching cylinder;

[0019] In the micro-etching process, the micro-etching grounding conductor is placed at the bottom of the micro-etching cylinder.

[0020] In some embodiments, the micro-etching grounding assembly further includes a micro-etching magnetic chuck connected to the micro-etching grounding conductor, and the first polymethyl methacrylate cured body is also coated and connected to the surface of the micro-etching magnetic chuck. The micro-etching magnetic chuck is located in the solution in the micro-etching tank and is magnetically connected to the activation tank.

[0021] In the micro-etching process, the micro-etching magnetic chuck is placed in the chemical solution of the micro-etching tank and magnetically connected to the micro-etching tank, so that the micro-etching grounding conductor is placed in the chemical solution of the micro-etching tank.

[0022] In some embodiments, the copper plating wire further includes an activation grounding assembly, which includes an activation grounding conductor, an activation grounding wire, and a second polymethyl methacrylate (PMMA) cured body. The activation grounding conductor is disposed in the chemical solution of the activation tank. One end of the activation grounding wire is electrically connected to the activation grounding conductor, and the other end of the activation grounding wire is electrically connected to the floor support. The second PMMA cured body is wrapped and connected to one end of the activation grounding wire. The activation grounding conductor is made of 316 stainless steel.

[0023] In the activation process, the activation grounding conductor is placed in the chemical solution in the activation tank. If there is a leakage, the activation grounding conductor is used to absorb the charge of the chemical solution in the activation tank, so that the activation grounding wire is used to guide the charge of the chemical solution in the activation tank to the floor support.

[0024] In some embodiments, the activation grounding conductor is disposed at the bottom of the activation cylinder;

[0025] In the activation process, the activation grounding conductor is placed at the bottom of the activation cylinder.

[0026] In some embodiments, the activation grounding assembly further includes an activation magnetic attractor connected to the activation grounding conductor, and the second polymethyl methacrylate cured body is also coated and connected to the surface of the activation magnetic attractor. The activation magnetic attractor is magnetically located in the chemical solution of the activation tank and is magnetically connected to the activation tank.

[0027] In the activation process, the activation magnetic attractor is placed in the solution of the activation tank and magnetically connected to the activation tank, so that the activation grounding conductor is placed in the solution of the activation tank.

[0028] In some embodiments, the copper plating wire further includes a copper plating grounding assembly, which includes a copper plating grounding conductor, a copper plating grounding wire, and a third polymethyl methacrylate (PMMA) cured body. The copper plating grounding conductor is disposed in the chemical solution of the copper plating tank. One end of the copper plating grounding wire is electrically connected to the copper plating grounding conductor, and the other end of the copper plating grounding wire is electrically connected to the floor support. The third PMMA cured body is wrapped and connected to one end of the copper plating grounding wire. The copper plating grounding conductor is made of 316 stainless steel.

[0029] In the copper melting process, the copper melting grounding conductor is placed in the chemical solution in the copper melting tank. If there is a leakage, the copper melting grounding conductor is used to absorb the charge of the chemical solution in the copper melting tank, so that the copper melting grounding wire is used to guide the charge of the chemical solution in the copper melting tank to the ground support.

[0030] In some embodiments, the copper-plating grounding conductor is disposed at the liquid surface of the copper-plating cylinder;

[0031] In the copper melting process, the copper melting grounding conductor is placed at the liquid level in the copper melting tank.

[0032] In some embodiments, the copper-based grounding assembly further includes a copper-based magnetic attractor connected to the copper-based grounding conductor, and the third polymethyl methacrylate cured body is also coated and connected to the surface of the copper-based magnetic attractor. The copper-based magnetic attractor is located in the solution of the copper-based tank and is magnetically connected to the copper-based tank.

[0033] In the copper melting process, the copper melting magnetic attractor is placed in the solution of the copper melting tank and magnetically connected to the copper melting tank, so that the copper melting grounding conductor is placed inside the copper melting tank.

[0034] A PCB board is prepared using the PCB hole metallization method based on suppressing leakage current as described in any of the above embodiments.

[0035] Compared with the prior art, this disclosure has at least the following advantages:

[0036] 1. The first polymethyl methacrylate (PMMA) cured body possesses strong chemical stability and is not prone to reacting with the chemicals in the micro-etching tank. This stability allows the first PMMA cured body to maintain its performance stability within the chemical solution, resulting in strong corrosion resistance in the micro-etching tank. Since the first PMMA cured body coats one end of the micro-etching grounding wire, specifically the exposed copper wire at one end, it protects the exposed copper wire, thereby enhancing the corrosion resistance of the exposed copper wire in the micro-etching tank's chemical solution.

[0037] 2. Although the first polymethyl methacrylate cured body covers the exposed copper wire at one end of the micro-etching grounding conductor, preventing the exposed copper wire at one end of the micro-etching grounding conductor from being directly electrically connected to the chemical solution, the micro-etching grounding conductor is located inside the chemical solution in the micro-etching tank. The exposed copper wire at one end of the micro-etching grounding conductor, the micro-etching grounding conductor, and the grounding support are electrically connected in sequence. This allows the chemical solution in the micro-etching tank to be grounded through the micro-etching grounding conductor, the micro-etching grounding conductor, and the grounding support in sequence, thereby suppressing the impact of leakage current on the micro-etching tank.

[0038] 3. 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the chromium and nickel elements in austenitic stainless steel can be evenly distributed to form a stable alloy phase, thereby improving the stainless steel's corrosion resistance. Therefore, 316 stainless steel has strong corrosion resistance, making it highly resistant to corrosion in chemicals containing micro-etching tanks. Because the micro-etching grounding conductor is made of 316 stainless steel, it has strong corrosion resistance in the chemical solution containing the micro-etching tank, thus making it highly corrosion resistant in the micro-etching tank.

[0039] 4. Because the exposed copper wire at one end of the micro-etching grounding conductor has strong corrosion resistance in the chemical solution of the micro-etching tank, and the micro-etching grounding conductor also has strong corrosion resistance in the micro-etching tank, the part of the micro-etching grounding component immersed in the micro-etching tank has strong corrosion resistance, thus extending the service life of the grounding treatment. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart illustrating the steps of a PCB via metallization method based on suppressing leakage current effects, according to one embodiment.

[0042] Figure 2 This is a partial structural diagram of a copper plating wire according to one embodiment;

[0043] Figure 3 for Figure 2 A partial structural diagram of the copper plating wire is shown;

[0044] Figure 4 for Figure 1 The diagram shows the structure of the copper plating wire.

[0045] Reference numerals: 100, floor support; 210, hole preparation cylinder; 220, micro-etching cylinder; 230, pre-immersion cylinder; 240, activation cylinder; 250, acceleration cylinder; 260, copper plating cylinder; 300, copper plating frame; 400, micro-etching grounding assembly; 410, micro-etching grounding conductor; 420, micro-etching grounding wire; 430, first polymethyl methacrylate cured body; 500, activation grounding assembly; 600, copper plating grounding assembly; 700, vibration grounding assembly. Detailed Implementation

[0046] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0047] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0048] 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 disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] This disclosure provides a PCB hole metallization method based on suppressing the influence of leakage current. The method uses a copper plating wire for hole metallization. The copper plating wire includes a support frame, a hole-forming cylinder, a micro-etching cylinder, a pre-dip cylinder, an activation cylinder, an acceleration cylinder, a copper-melting cylinder, and a copper plating frame. The hole-forming cylinder, micro-etching cylinder, pre-dip cylinder, acceleration cylinder, and copper-melting cylinder are sequentially arranged on the support frame. The copper plating frame is used to sequentially immerse the PCB board into the hole-forming cylinder, micro-etching cylinder, pre-dip cylinder, acceleration cylinder, and copper-melting cylinder. The copper plating wire also includes a micro-etching grounding assembly, which includes a micro-etching grounding conductor, a micro-etching grounding wire, and a first polymethyl methacrylate (PMMA) cured body. The micro-etching grounding conductor is placed in the chemical solution of the micro-etching cylinder. One end of the micro-etching grounding wire is electrically connected to the micro-etching grounding conductor, and the other end of the micro-etching grounding wire is electrically connected to the support frame. The first PMMA cured body is coated and connected to one end of the micro-etching grounding wire. The micro-etching grounding conductor is made of 316 stainless steel.

[0050] The PCB hole metallization method based on suppressing leakage current includes: hole cleaning treatment for cleaning grease from the PCB board surface; micro-etching treatment for removing oxides from the copper surface of the PCB board and etching the copper surface of the PCB board; wherein, a micro-etching grounding conductor is placed in the micro-etching tank, and if leakage current occurs, the micro-etching grounding conductor is used to absorb the charge of the chemical solution in the micro-etching tank, so that the micro-etching grounding wire is used to guide the charge of the chemical solution in the micro-etching tank to the ground support; pre-immersion treatment for forming a protective film on the hole walls and surface of the PCB board; activation treatment for adhering palladium colloid to the hole walls of the PCB board; acceleration treatment for removing the tin colloid layer on the PCB board surface and inside the holes, exposing the palladium colloid layer; and copper plating treatment for forming a copper layer on the hole walls of the PCB board.

[0051] This disclosure also provides a PCB board prepared using the above-described PCB hole metallization method based on suppressing leakage current effects.

[0052] The aforementioned PCB via metallization method based on suppressing leakage current utilizes a first polymethyl methacrylate (PMMA) cured body with strong chemical stability, making it less prone to reacting with the etching solution in the micro-etching tank. This stability allows the first PMMA cured body to maintain its performance stability within the etching solution, resulting in strong corrosion resistance. Since the first PMMA cured body coats one end of the micro-etching grounding conductor—specifically, the exposed copper wire at one end—it protects the exposed copper wire, further enhancing its corrosion resistance within the etching solution.

[0053] Furthermore, although the first polymethyl methacrylate cured body covers the exposed copper wire at one end of the micro-etching grounding conductor, preventing the exposed copper wire at one end of the micro-etching grounding conductor from being directly electrically connected to the chemical solution, the micro-etching grounding conductor is located inside the chemical solution within the micro-etching tank, and the exposed copper wire at one end of the micro-etching grounding conductor, the micro-etching grounding conductor, and the grounding support are sequentially electrically connected. This allows the chemical solution in the micro-etching tank to be grounded sequentially through the micro-etching grounding conductor, the micro-etching grounding conductor, and the grounding support, thereby suppressing the impact of leakage current on the micro-etching tank.

[0054] Furthermore, 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the chromium and nickel elements in austenitic stainless steel can be evenly distributed to form a stable alloy phase, thereby improving the stainless steel's corrosion resistance. Therefore, 316 stainless steel has strong corrosion resistance, making it highly resistant to corrosion in chemicals containing micro-etching tanks. Because the micro-etching grounding conductor is made of 316 stainless steel, it has strong corrosion resistance in the chemical solution containing the micro-etching tank, thus making it highly corrosion resistant in the micro-etching tank.

[0055] Furthermore, because the exposed copper wire at one end of the micro-etching grounding conductor has strong corrosion resistance in the chemical solution of the micro-etching tank, and the micro-etching grounding conductor also has strong corrosion resistance in the micro-etching tank, the part of the micro-etching grounding component immersed in the micro-etching tank has strong corrosion resistance, thus extending the service life of the grounding treatment.

[0056] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0057] like Figures 1 to 4As shown, one embodiment of a PCB hole metallization method based on suppressing leakage current influence uses copper plating wire for hole metallization. The copper plating wire includes a floor support 100, a hole preparation cylinder 210, a micro-etching cylinder 220, a pre-dip cylinder 230, an activation cylinder 240, an acceleration cylinder 250, a copper melting cylinder 260, and a copper plating frame 300. The hole preparation cylinder 210, micro-etching cylinder 220, pre-dip cylinder 230, acceleration cylinder 250, and copper melting cylinder are sequentially arranged on the floor support 100. The copper plating frame 300 is used to sequentially immerse the PCB board into the hole preparation cylinder 210, micro-etching cylinder 220, pre-dip cylinder 230, acceleration cylinder 250, and copper melting cylinder, so that the PCB board sequentially undergoes hole preparation treatment, micro-etching treatment, pre-dip treatment, acceleration treatment, and copper melting treatment. The copper plating wire also includes a micro-etching grounding assembly 400, which includes a micro-etching grounding conductor 410, a micro-etching grounding wire 420, and a first polymethyl methacrylate (PMMA) cured body 430. The micro-etching grounding conductor 410 is placed in the chemical solution of the micro-etching tank 220. One end of the micro-etching grounding wire 420 is electrically connected to the micro-etching grounding conductor 410, and the other end of the micro-etching grounding wire 420 is electrically connected to the floor support 100. The first PMMA cured body 430 covers and connects to one end of the micro-etching grounding wire 420, specifically covering the exposed copper wire connected to one end of the micro-etching grounding wire 420. The micro-etching grounding conductor 410 is made of 316 stainless steel. The first PMMA cured body 430 can be understood as an acrylic colloid. Furthermore, the micro-etching tank contains a micro-etching solution, which includes sodium persulfate and 3-5% sulfuric acid.

[0058] In this embodiment, the first polymethyl methacrylate cured body 430 has strong chemical stability and is not easily reacted with the chemical solution in the micro-etching tank 220. This stability allows the first polymethyl methacrylate cured body 430 to maintain its performance stability in the chemical solution in the micro-etching tank, making the first polymethyl methacrylate cured body 430 corrosion resistant in the micro-etching tank 220. In turn, the first polymethyl methacrylate cured body 430 can protect the exposed copper wire at one end of the micro-etching grounding wire 420.

[0059] Furthermore, 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the uniform distribution of chromium and nickel in austenitic stainless steel forms a stable alloy phase, thereby enhancing its corrosion resistance.

[0060] like Figures 1 to 4 As shown, in some embodiments, the PCB via metallization method based on suppressing leakage current effects includes:

[0061] S101, Hole cleaning treatment, used to clean grease from the surface of the PCB board.

[0062] In this embodiment, after removing the adhesive from the PCB board, a hole-refining process is performed. This process thoroughly cleans the hole walls of the PCB board, removing impurities, grease, and other contaminants generated during drilling or other processing. The hole-refining agent used has a certain degree of wetting properties, allowing it to penetrate into the hole walls of the PCB board, making the hole wall surface more uniform and wet. This helps the subsequent electroplating solution adhere better to the hole walls, forming a uniform and dense electroplating layer. The hole-refining process also improves the electrical properties of the hole walls, giving them better conductivity. This is crucial for electrical connections on the circuit board, as good conductivity ensures smooth current transmission across the circuit board, thereby improving the overall performance and stability of the circuit board.

[0063] S103, Micro-etching treatment, used to remove oxides on the copper surface of the PCB board and etch the copper surface of the PCB board; wherein, the micro-etching grounding conductor 410 is set in the micro-etching tank 220. If there is leakage, the micro-etching grounding conductor 410 is used to absorb the charge of the chemical solution in the micro-etching tank 220, so that the micro-etching grounding wire 420 is used to guide the charge of the chemical solution in the micro-etching tank 220 to the floor support 100.

[0064] In this embodiment, micro-etching removes impurities and oxide layers through a chemical reaction, resulting in a cleaner circuit board surface. Micro-etching also roughens the circuit board surface, increasing surface active sites, which facilitates better adhesion of the electroplated layer. Micro-etching improves the bonding strength between the electroplated layer and the circuit board, thereby enhancing the overall mechanical strength and stability of the circuit board. A micro-etching grounding conductor 410 is placed in the chemical solution within the micro-etching tank 220, connecting the chemical solution in the tank 220, the micro-etching grounding conductor 410, the micro-etching grounding wire 420, and the floor support 100 in sequence. In case of leakage, the micro-etching grounding conductor 410 absorbs the charge from the chemical solution in the micro-etching tank 220, while the micro-etching grounding wire 420 guides the charge from the chemical solution in the tank 220 to the floor support 100, thus diverting the leakage current from the micro-etching tank 220 to the ground.

[0065] S105, Pre-impregnation treatment, used to form a protective film on the hole walls and surface of a PCB board.

[0066] In this embodiment, pre-immersion can remove impurities such as oil and dust that may be present on the PCB board surface, providing a clean surface for subsequent copper plating. The pre-immersion solution used in the pre-immersion treatment can adjust the polarity of the PCB board surface, making it easier to adsorb subsequent colloidal palladium particles, thereby ensuring the uniformity, continuity, and density of the copper plating. Through pre-immersion treatment, the adhesion between the PCB board surface and the subsequent electroplating layer can be enhanced, improving the mechanical strength and stability of the entire PCB board.

[0067] S107, Activation treatment, used to make palladium colloid adhere to the hole walls of the PCB board.

[0068] In this embodiment, the activation process is carried out by immersing the PCB board in a solution containing an activator. The activator can remove oxides and contaminants from the surface of the hole walls, and a uniform palladium colloidal layer will be formed on the hole walls of the PCB board. This colloidal layer has excellent catalytic activity, which can improve the uniformity and quality of the subsequent electroplated copper layer.

[0069] S109, Accelerated Processing, used to remove the tin colloid layer from the surface and holes of the PCB board, exposing the palladium colloid layer.

[0070] In this embodiment, during the activation process, a tin colloid layer forms on the PCB surface, covering the palladium colloid layer and hindering the subsequent electroless copper plating process. Specifically, the presence of the tin colloid layer interferes with the reduction and deposition of copper ions, leading to uneven, discontinuous, or even impossible copper plating. Therefore, the PCB is subjected to an accelerated treatment to remove the tin colloid layer from the board surface and holes. During the accelerated treatment, the accelerating liquid in the accelerating cylinder 250 reacts with the tin colloid layer, generating soluble compounds or decomposing it into small molecules. These substances are then removed from the PCB surface and holes through rinsing and other steps. After the accelerated treatment, the palladium colloid layer, originally covered by the tin colloid layer, is exposed again, providing a good catalytic center for the subsequent electroless copper plating process. This ensures that copper ions can be uniformly reduced and deposited on the PCB surface and holes, forming a continuous and dense copper layer, thereby improving the conductivity, mechanical strength, and soldering reliability of the PCB.

[0071] S201, copper plating treatment, is used to form a copper layer on the hole walls of a PCB board.

[0072] In this embodiment, the copper ionization process uses formaldehyde as a reducing agent and palladium colloid layer as a catalyst. In an alkaline solution, copper ions are reduced to metallic copper, which adheres to the hole walls of the PCB board, thus forming a copper layer on the hole walls of the PCB.

[0073] The aforementioned PCB via metallization method based on suppressing leakage current utilizes a first polymethyl methacrylate (PMMA) cured body 430, which exhibits strong chemical stability and is unlikely to react with the etching solution in the micro-etching tank 220. This stability allows the first PMMA cured body 430 to maintain stable performance within the etching solution, resulting in strong corrosion resistance in the micro-etching tank 220. Since the first PMMA cured body 430 covers one end of the micro-etching grounding conductor 420, specifically the exposed copper wire at one end, it protects the exposed copper wire at that end, further enhancing the corrosion resistance of the exposed copper wire in the etching tank 220.

[0074] Furthermore, although the first polymethyl methacrylate cured body 430 covers the exposed copper wire connected to one end of the micro-etching grounding conductor 420, preventing the exposed copper wire at one end of the micro-etching grounding conductor 420 from being directly electrically connected to the chemical solution, the micro-etching grounding conductor 410 is located inside the chemical solution in the micro-etching tank 220, and the exposed copper wire at one end of the micro-etching grounding conductor 410, the micro-etching grounding conductor 420, and the floor support 100 are sequentially electrically connected. This allows the chemical solution in the micro-etching tank 220 to be grounded sequentially through the micro-etching grounding conductor 410, the micro-etching grounding conductor 420, and the floor support 100, thereby suppressing the impact of leakage current on the micro-etching tank 220.

[0075] Furthermore, 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the chromium and nickel elements in austenitic stainless steel can be evenly distributed to form a stable alloy phase, thereby improving the stainless steel's corrosion resistance. Therefore, 316 stainless steel has strong corrosion resistance, making it highly resistant to corrosion in chemicals containing micro-etching tanks. Because the micro-etching grounding conductor 410 is made of 316 stainless steel, it has strong corrosion resistance in the solution containing the micro-etching tank, thus making it highly corrosion resistant in the micro-etching tank 220.

[0076] Furthermore, since the exposed copper wire at one end of the micro-etching grounding conductor 420 has strong corrosion resistance in the chemical solution of the micro-etching tank 220, and the micro-etching grounding conductor 410 has strong corrosion resistance in the micro-etching tank 220, the part of the micro-etching grounding component 400 immersed in the micro-etching tank 220 has strong corrosion resistance, thus extending the service life of the grounding treatment.

[0077] like Figure 4 As shown, in some embodiments, the micro-etching grounding conductor 410 is disposed at the bottom of the micro-etching tank 220, that is, the micro-etching grounding conductor 410 is immersed in the bottom of the micro-etching tank 220. Further, in the micro-etching process, the micro-etching grounding conductor 410 is disposed at the bottom of the micro-etching tank 220.

[0078] like Figure 4As shown, in this embodiment, an ultrasonic vibrator is installed at the bottom of the micro-etching tank 220. However, the ultrasonic vibrator has the risk of leakage. When the ultrasonic vibrator in the micro-etching tank 220 leaks electricity, the micro-etching grounding conductor 410 can absorb the leaked charge in time, and let the leaked charge reach the ground through the micro-etching grounding wire 420 and the ground support 100 in sequence. This timely suppresses the impact of the leakage of the ultrasonic vibrator in the micro-etching tank 220 on the micro-etching process, thereby avoiding the impact of the ultrasonic vibrator leakage on the micro-etching process.

[0079] In some embodiments, the micro-etching grounding assembly 400 further includes a micro-etching magnetic chuck connected to the micro-etching grounding conductor 410. A first polymethyl methacrylate cured body 430 is also coated and connected to the surface of the micro-etching magnetic chuck. The micro-etching magnetic chuck is located in the chemical solution of the micro-etching tank 220 and magnetically connected to the activation tank 240. Further, in the micro-etching process, the micro-etching magnetic chuck is placed in the chemical solution of the micro-etching tank 220 and magnetically connected to the micro-etching tank 220, so that the micro-etching grounding conductor 410 is placed in the chemical solution of the micro-etching tank 220.

[0080] In this embodiment, since the micro-etching magnetic suction component is magnetically connected to the micro-etching cylinder 220, the positions of the micro-etching suction component and the micro-etching grounding conductor 410 are adjustable. Therefore, in the actual preparation process, the micro-etching suction component can be adsorbed to the position where leakage is most concentrated, so that the micro-etching grounding conductor 410 is fixed at the position where leakage is most concentrated. This allows the micro-etching grounding component 400 to guide the leakage to the ground more promptly, further reducing the impact of leakage from the ultrasonic vibrator on the micro-etching process.

[0081] It should be noted that, theoretically, the leakage current of the micro-etching tank 220 is mainly concentrated at the bottom, but in the actual preparation process, the location of leakage current may sometimes change.

[0082] like Figure 4 As shown, in some embodiments, the copper plating wire further includes an activation grounding assembly 500. The activation grounding assembly 500 includes an activation grounding conductor, an activation grounding wire, and a second polymethyl methacrylate (PMMA) cured body. The activation grounding conductor is disposed in the chemical solution of the activation tank 240. One end of the activation grounding wire is electrically connected to the activation grounding conductor, and the other end of the activation grounding wire is electrically connected to the floor support 100. The second PMMA cured body covers and connects to one end of the activation grounding wire, specifically covering the exposed copper wire at one end of the activation grounding wire. The activation grounding conductor is made of 316 stainless steel. It can be understood that the second PMMA cured body is an acrylic colloid. Further, the activation tank contains an activation solution, which includes 5% hydrochloric acid.

[0083] like Figure 4As shown, further, in the activation process, an activation grounding conductor is placed in the chemical solution in the activation tank 240. If there is a leakage, the activation grounding conductor is used to absorb the charge of the chemical solution in the activation tank 240, so that the activation grounding wire is used to guide the charge of the chemical solution in the activation tank 240 to the floor support 100.

[0084] In this embodiment, the second polymethyl methacrylate (PMMA) cured body exhibits strong chemical stability and is not prone to reacting with the chemicals in the activation tank 240. This stability allows the second PMMA cured body to maintain its performance stability in a solution containing 5% hydrochloric acid, resulting in strong corrosion resistance within the activation tank 240. Since the second PMMA cured body covers one end of the activation grounding wire, specifically the exposed copper wire at one end, it protects the exposed copper wire, further enhancing its corrosion resistance in the chemicals within the activation tank 240.

[0085] Furthermore, although the second polymethyl methacrylate cured body covers the exposed copper wire connected to one end of the activation grounding conductor, preventing the exposed copper wire at one end of the activation grounding conductor from being directly electrically connected to the solution, the activation grounding conductor is located inside the solution within the activation tank 240, and the exposed copper wire at one end of the activation grounding conductor, the activation grounding conductor, and the floor support 100 are sequentially electrically connected. This allows the solution in the activation tank 240 to be grounded sequentially through the activation grounding conductor, the activation grounding conductor, and the floor support 100, thereby suppressing the impact of leakage current on the activation tank 240.

[0086] Furthermore, 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the chromium and nickel elements in austenitic stainless steel can be evenly distributed to form a stable alloy phase, thereby improving the corrosion resistance of the stainless steel. Therefore, 316 stainless steel has strong corrosion resistance, making it highly resistant to corrosion in solutions containing 5% hydrochloric acid. Because the activated grounding conductor is made of 316 stainless steel, it has strong corrosion resistance in a solution containing 5% hydrochloric acid, which also makes it highly corrosion resistant in the activation tank 240.

[0087] Furthermore, since the exposed copper wire at one end of the activated grounding conductor has strong corrosion resistance in the chemical solution of the activation tank 240, and the activated grounding conductor also has strong corrosion resistance in the activation tank 240, the part of the activated grounding component 500 immersed in the activation tank 240 has strong corrosion resistance, thus extending the service life of the grounding treatment.

[0088] like Figure 4 As shown, in some embodiments, the activation grounding conductor is disposed at the bottom of the activation tank 240, that is, the activation grounding conductor is immersed in the activation tank 240. Further, in the activation process, the activation grounding conductor is disposed at the bottom of the activation tank 240, that is, the activation grounding conductor is immersed in the activation tank 240.

[0089] like Figure 4 As shown, in this embodiment, an ultrasonic vibrator is installed at the bottom of the activation cylinder 240. However, the ultrasonic vibrator has the risk of leakage. When the ultrasonic vibrator in the activation cylinder 240 leaks electricity, the activation grounding conductor can absorb the leaked charge in time, and the leaked charge will reach the ground through the activation grounding wire and the ground support 100 in sequence. This timely suppresses the impact of the leakage of the ultrasonic vibrator in the activation cylinder 240 on the activation process, thereby avoiding the impact of the ultrasonic vibrator leakage on the activation process.

[0090] In some embodiments, the activation grounding assembly 500 further includes an activation magnetic attractor connected to the activation grounding conductor. A second polymethyl methacrylate cured body is also coated and connected to the surface of the activation magnetic attractor. The activation magnetic attractor is magnetically located in the chemical solution of the activation tank 240 and magnetically connected to the activation tank 240. Further, during the activation process, the activation magnetic attractor is placed in the chemical solution of the activation tank 240 and magnetically connected to the activation tank 240, so that the activation grounding conductor is placed in the chemical solution of the activation tank 240. In this embodiment, because the activation magnetic attractor is magnetically connected to the activation tank 240, the positions of the activation attractor and the activation grounding conductor are adjustable. Therefore, in the actual preparation process, the activation attractor can be attracted to the location where leakage current is most concentrated, so that the activation grounding conductor is fixed at the location where leakage current is most concentrated. This allows the activation grounding assembly 500 to guide leakage current to the ground more promptly, further reducing the impact of leakage current from the ultrasonic vibrator on the activation process.

[0091] It should be noted that, theoretically, the leakage current in the activation tank 240 is mainly concentrated at the bottom, but in the actual preparation process, the location of the leakage current may sometimes change.

[0092] like Figure 4 As shown, in some embodiments, the copper plating wire further includes a copper plating grounding assembly 600. The copper plating grounding assembly 600 includes a copper plating grounding conductor, a copper plating grounding wire, and a third polymethyl methacrylate (PMMA) cured body. The copper plating grounding conductor is disposed in the chemical solution of the copper plating tank. One end of the copper plating grounding wire is electrically connected to the copper plating grounding conductor, and the other end of the copper plating grounding wire is electrically connected to the floor support 100. The third PMMA cured body is wrapped and connected to one end of the copper plating grounding wire. The copper plating grounding conductor is made of 316 stainless steel. It can be understood that the third PMMA cured body is an acrylic colloid. Further, the copper plating tank contains a copper plating solution, which includes sodium hydroxide.

[0093] like Figure 4 As shown, further, in the copper melting process, the copper melting grounding conductor is placed in the chemical solution in the copper melting tank. If there is a leakage, the copper melting grounding conductor is used to absorb the charge of the chemical solution in the copper melting tank, so that the copper melting grounding wire is used to guide the charge of the chemical solution in the copper melting tank to the floor support 100.

[0094] In this embodiment, the third polymethyl methacrylate (PMMA) cured body exhibits strong chemical stability and is not prone to reacting with the chemicals in the copper annealing tank. This stability allows the PMMA cured body to maintain its performance stability in the sodium hydroxide-containing solution, resulting in strong corrosion resistance within the copper annealing tank. Since the PMMA cured body covers one end of the copper annealing grounding wire—specifically, it covers the exposed copper wire at one end—it protects the exposed copper wire, further enhancing its corrosion resistance within the copper annealing tank's chemicals.

[0095] Furthermore, although the third polymethyl methacrylate cured body covers the exposed copper wire at one end of the copper-melting grounding conductor, preventing the exposed copper wire at one end of the copper-melting grounding conductor from being directly electrically connected to the chemical solution, the copper-melting grounding conductor is located inside the chemical solution within the copper-melting tank. The exposed copper wire at one end of the copper-melting grounding conductor, the copper-melting grounding conductor, and the floor support 100 are sequentially electrically connected. This allows the chemical solution in the copper-melting tank to be grounded sequentially through the copper-melting grounding conductor, the copper-melting grounding conductor, and the floor support 100, thereby suppressing the impact of leakage current on the copper-melting tank.

[0096] Furthermore, 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the chromium and nickel elements in austenitic stainless steel can be evenly distributed to form a stable alloy phase, thereby improving the corrosion resistance of the stainless steel. Therefore, 316 stainless steel has strong corrosion resistance, making it highly resistant to corrosion in solutions containing sodium hydroxide. Because the copper-plating grounding conductor is made of 316 stainless steel, it has strong corrosion resistance in solutions containing sodium hydroxide, thus making it highly corrosion-resistant in the copper plating tank.

[0097] Furthermore, because the exposed copper wire at one end of the copper-plating grounding conductor has strong corrosion resistance in the chemical solution of the copper-plating tank, and the copper-plating grounding conductor also has strong corrosion resistance in the copper-plating tank, the part of the copper-plating grounding component 600 immersed in the copper-plating tank has strong corrosion resistance, thus extending the service life of the grounding treatment.

[0098] It should be noted that the first polymethyl methacrylate (PMMA) cured body, the second PMMA cured body, and the third PMMA cured body are made of the same or different materials. The PMMA is made of acrylic powder and metallographic curing agent. Both acrylic powder and metallographic curing agent are commercially available. In this case, both acrylic powder and metallographic curing agent were purchased from SPK Company.

[0099] like Figure 4 As shown, in some embodiments, the copper-melting grounding conductor is positioned at the surface of the copper-melting tank, i.e., the copper-melting grounding conductor is submerged at the surface of the copper-melting tank. Further, in the copper-melting process, the copper-melting grounding conductor is positioned at the surface of the copper-melting tank, i.e., the copper-melting grounding conductor is submerged at the surface of the copper-melting tank.

[0100] like Figure 4 As shown, in this embodiment, no ultrasonic vibration device is installed inside the copper melting tank, but an oscillation device is installed on the copper melting frame 300. This oscillation device poses a risk of leakage, which can be conducted to the copper melting frame 300 when it leaks. Since the copper melting frame 300 is the first to contact the liquid surface of the copper melting tank during the copper melting process, the leakage will first be conducted to the liquid surface through the copper melting frame 300. Therefore, a copper melting grounding conductor is placed at the liquid surface of the copper melting tank, allowing the grounding conductor to absorb the leaked charge in a timely manner during copper melting. The leaked charge then passes through the grounding wire and the grounding support 100 to reach the ground, effectively suppressing the impact of leaked charge in the copper melting tank on the copper melting process.

[0101] In some embodiments, the copper-based grounding assembly 600 further includes a copper-based magnetic attractor connected to the copper-based grounding conductor. A third polymethyl methacrylate (PMMA) cured body is also coated and connected to the surface of the copper-based magnetic attractor. The copper-based magnetic attractor is located in the solution of the copper-based melting tank and is magnetically connected to the tank. Further, during the copper-based melting process, the copper-based magnetic attractor is placed in the solution of the melting tank and magnetically connected to it, so that the copper-based grounding conductor is placed inside the melting tank. In this embodiment, because the copper-based magnetic attractor is magnetically connected to the melting tank, the positions of the attractor and the grounding conductor are adjustable. Therefore, in the actual preparation process, the attractor can be attracted to the location where leakage current is most concentrated, fixing the grounding conductor at the location where leakage current is most concentrated. This allows the copper-based grounding assembly 600 to guide leakage current to the ground more promptly, further reducing the impact of leakage current on the copper-based melting process.

[0102] It should be noted that, theoretically, the leakage current of copper melting cylinder 260 is mainly concentrated at the liquid surface, but in the actual preparation process, the location of leakage current may sometimes change.

[0103] like Figure 4As shown, in some embodiments, the copper plating wire further includes a resonant grounding assembly 700. The resonant grounding assembly 700 includes a resonant grounding conductor, a resonant grounding wire, and a fourth polymethyl methacrylate (PMMA) cured body. The resonant grounding conductor is connected to the copper plating frame 300. A first end of the resonant grounding wire is electrically connected to the resonant grounding conductor, and a second end of the resonant grounding wire is electrically slidably connected to the floor support 100. The fourth PMMA cured body is coated and connected to one end of the resonant grounding wire. It can be understood that the fourth PMMA cured body is an acrylic colloid.

[0104] like Figure 4 As shown, in this embodiment, when the copper plating frame 300 moves, it will drive the resonant grounding component 700 to move, causing the second end of the resonant grounding conductor to be electrically connected to the grounding support 100. The copper plating frame 300 is equipped with a resonant device, which poses a risk of leakage. When the resonant device leaks current, the leakage will be conducted to the copper plating frame 300. At this time, the resonant grounding conductor will promptly absorb the leaked charge, and the leaked charge will sequentially pass through the resonant grounding conductor and the grounding support 100 to reach the ground, thus avoiding the impact of the leaked charge from the resonant device on the metallization process.

[0105] This disclosure also provides a PCB board prepared using the PCB hole metallization method based on suppressing leakage current as described in any of the above embodiments.

[0106] The aforementioned PCB board exhibits strong chemical stability in its first polymethyl methacrylate (PMMA) cured body 430, making it resistant to reaction with the etching solution in the micro-etching tank 220. This stability allows the PMMA cured body 430 to maintain stable performance within the etching solution, resulting in strong corrosion resistance within the micro-etching tank 220. Since the PMMA cured body 430 covers one end of the micro-etching grounding conductor 420—specifically, covers the exposed copper wire at one end of the grounding conductor 420—it protects the exposed copper wire at one end of the grounding conductor 420, thereby enhancing the corrosion resistance of the exposed copper wire at one end of the grounding conductor 420 within the etching tank 220.

[0107] Although the first polymethyl methacrylate cured body 430 covers the exposed copper wire connected to one end of the micro-etching grounding conductor 420, preventing the exposed copper wire at one end of the micro-etching grounding conductor 420 from being directly electrically connected to the chemical solution, the micro-etching grounding conductor 410 is located inside the chemical solution in the micro-etching tank 220, and the exposed copper wire at one end of the micro-etching grounding conductor 410, the micro-etching grounding conductor 420, and the floor support 100 are sequentially electrically connected. This allows the chemical solution in the micro-etching tank 220 to be grounded sequentially through the micro-etching grounding conductor 410, the micro-etching grounding conductor 420, and the floor support 100, thereby suppressing the impact of leakage current on the micro-etching tank 220.

[0108] 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency for intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the uniform distribution of chromium and nickel in austenitic stainless steel forms a stable alloy phase, thereby enhancing its corrosion resistance. Therefore, 316 stainless steel exhibits strong corrosion resistance, making it highly resistant to corrosion in chemicals containing micro-etching tanks. Because the micro-etching grounding conductor 410 is made of 316 stainless steel, it has strong corrosion resistance in the solution containing the micro-etching tank, thus making it highly corrosion resistant in the micro-etching tank 220.

[0109] Because the exposed copper wire at one end of the micro-etching grounding conductor 420 has strong corrosion resistance in the chemical solution of the micro-etching tank 220, and the micro-etching grounding conductor 410 also has strong corrosion resistance in the micro-etching tank 220, the part of the micro-etching grounding component 400 immersed in the micro-etching tank 220 has strong corrosion resistance, thus extending the service life of the grounding treatment.

[0110] Compared with the prior art, this disclosure has at least the following advantages:

[0111] 1. The first polymethyl methacrylate (PMMA) cured body 430 possesses strong chemical stability and is not prone to reacting with the chemicals in the micro-etching tank 220. This stability allows the first PMMA cured body 430 to maintain its performance stability in the chemicals within the micro-etching tank 220, resulting in strong corrosion resistance. Since the first PMMA cured body 430 covers and connects to one end of the micro-etching grounding wire 420, specifically covering the exposed copper wire at one end of the micro-etching grounding wire 420, it protects the exposed copper wire at one end of the micro-etching grounding wire 420, thereby enhancing the corrosion resistance of the exposed copper wire at one end of the micro-etching grounding wire 420 in the chemicals within the micro-etching tank 220.

[0112] 2. Although the first polymethyl methacrylate cured body 430 covers the exposed copper wire at one end of the micro-etching grounding conductor 420, preventing the exposed copper wire at one end of the micro-etching grounding conductor 420 from being directly electrically connected to the chemical solution, the micro-etching grounding conductor 410 is located inside the chemical solution in the micro-etching tank 220, and the exposed copper wire at one end of the micro-etching grounding conductor 410, the micro-etching grounding conductor 420, and the floor support 100 are sequentially electrically connected. This allows the chemical solution in the micro-etching tank 220 to be grounded sequentially through the micro-etching grounding conductor 410, the micro-etching grounding conductor 420, and the floor support 100, thereby suppressing the impact of leakage current on the micro-etching tank 220.

[0113] 3. 316 stainless steel belongs to the chromium-nickel austenitic stainless steel family, containing a high proportion of chromium and nickel in its alloy composition. Chromium is one of the most important alloying elements in 316 stainless steel, significantly improving its corrosion resistance. Chromium combines with oxygen to form a dense chromium oxide protective film, which prevents corrosive substances from directly contacting the stainless steel matrix, thus slowing down the corrosion process. Nickel enhances the strength and toughness of 316 stainless steel, while also contributing to its corrosion resistance. Nickel stabilizes the austenitic structure, reducing the tendency of 316 stainless steel to undergo intergranular corrosion in corrosive environments, further improving its corrosion resistance. The microstructure of 316 stainless steel is austenitic, and the chromium and nickel elements in austenitic stainless steel can be evenly distributed to form a stable alloy phase, thereby improving the stainless steel's corrosion resistance. Therefore, 316 stainless steel has strong corrosion resistance, making it highly resistant to corrosion in chemicals containing micro-etching tanks. Because the micro-etching grounding conductor 410 is made of 316 stainless steel, it has strong corrosion resistance in the solution containing the micro-etching tank, thus making it highly corrosion resistant in the micro-etching tank 220.

[0114] 4. Because the exposed copper wire at one end of the micro-etching grounding conductor 420 has strong corrosion resistance in the chemical solution of the micro-etching tank 220, and the micro-etching grounding conductor 410 has strong corrosion resistance in the micro-etching tank 220, the part of the micro-etching grounding component 400 immersed in the micro-etching tank 220 has strong corrosion resistance, thus extending the service life of the grounding treatment.

[0115] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A PCB hole metallization method based on suppressing leakage current, comprising a copper plating line for hole metallization, wherein the copper plating line includes a floor support, a hole-forming cylinder, a micro-etching cylinder, a pre-dip cylinder, an activation cylinder, an acceleration cylinder, a copper-plating cylinder, and a copper plating frame; the hole-forming cylinder, the micro-etching cylinder, the pre-dip cylinder, the activation cylinder, the acceleration cylinder, and the copper-plating cylinder are sequentially arranged on the floor support, and the copper plating frame is used to sequentially immerse the PCB board into the hole-forming cylinder, the micro-etching cylinder, the pre-dip cylinder, the acceleration cylinder, and the copper-plating cylinder; characterized in that, The copper plating wire also includes a micro-etching grounding assembly, which includes a micro-etching grounding conductor, a micro-etching grounding wire, and a first polymethyl methacrylate (PMMA) cured body. The micro-etching grounding conductor is disposed in the chemical solution of the micro-etching tank. One end of the micro-etching grounding wire is electrically connected to the micro-etching grounding conductor, and the other end of the micro-etching grounding wire is electrically connected to the floor support. The first PMMA cured body is wrapped and connected to one end of the micro-etching grounding wire. The micro-etching grounding conductor is made of 316 stainless steel. The PCB hole metallization method based on suppressing leakage current includes: Hole cleaning process is used to clean the grease from the surface of the PCB board; Micro-etching is used to remove oxides from the copper surface of the PCB board and etch the copper surface of the PCB board; wherein, the micro-etching grounding conductor is placed in the chemical solution of the micro-etching tank. If there is leakage, the micro-etching grounding conductor is used to absorb the charge of the chemical solution in the micro-etching tank, so that the micro-etching grounding wire is used to guide the charge of the chemical solution in the micro-etching tank to the floor support. Pre-impregnation treatment is used to form a protective film on the hole walls and surface of the PCB board; Activation treatment is used to allow palladium colloid to adhere to the hole walls of the PCB board; Accelerated processing is used to remove the tin colloid layer from the surface and holes of the PCB board, exposing the palladium colloid layer. Copper plating is used to form a copper layer on the hole walls of the PCB board. The micro-etching grounding assembly further includes a micro-etching magnetic chuck, which is connected to the micro-etching grounding conductor. The first polymethyl methacrylate cured body is also coated and connected to the surface of the micro-etching magnetic chuck. The micro-etching magnetic chuck is located in the solution in the micro-etching tank and is magnetically connected to the activation tank. In the micro-etching process, the micro-etching magnetic suction component is placed in the chemical solution of the micro-etching tank and magnetically connected to the micro-etching tank, so that the micro-etching grounding conductor is placed in the chemical solution of the micro-etching tank; The copper plating wire further includes an activation grounding assembly, which includes an activation grounding conductor, an activation grounding wire, and a second polymethyl methacrylate (PMMA) cured body. The activation grounding conductor is disposed in the chemical solution of the activation tank. One end of the activation grounding wire is electrically connected to the activation grounding conductor, and the other end of the activation grounding wire is electrically connected to the floor support. The second PMMA cured body is wrapped and connected to one end of the activation grounding wire. The activation grounding conductor is made of 316 stainless steel. In the activation process, the activation grounding conductor is placed in the chemical solution in the activation tank. If there is a leakage, the activation grounding conductor is used to absorb the charge of the chemical solution in the activation tank, so that the activation grounding wire is used to guide the charge of the chemical solution in the activation tank to the floor support. The copper plating wire further includes a copper plating grounding assembly, which includes a copper plating grounding conductor, a copper plating grounding wire, and a third polymethyl methacrylate (PMMA) cured body. The copper plating grounding conductor is disposed in the chemical solution of the copper plating tank. One end of the copper plating grounding wire is electrically connected to the copper plating grounding conductor, and the other end of the copper plating grounding wire is electrically connected to the floor support. The third PMMA cured body is wrapped and connected to one end of the copper plating grounding wire. The copper plating grounding conductor is made of 316 stainless steel. In the copper melting process, the copper melting grounding conductor is placed in the chemical solution in the copper melting tank. If there is a leakage, the copper melting grounding conductor is used to absorb the charge of the chemical solution in the copper melting tank, so that the copper melting grounding wire is used to guide the charge of the chemical solution in the copper melting tank to the ground support.

2. The PCB hole metallization method based on suppressing leakage current as described in claim 1, characterized in that, The micro-etching grounding conductor is located at the bottom of the micro-etching cylinder; In the micro-etching process, the micro-etching grounding conductor is placed at the bottom of the micro-etching cylinder.

3. The PCB hole metallization method based on suppressing leakage current as described in claim 1, characterized in that, The activation grounding conductor is located at the bottom of the activation cylinder; In the activation process, the activation grounding conductor is placed at the bottom of the activation cylinder.

4. The PCB hole metallization method based on suppressing leakage current as described in claim 1, characterized in that, The activation grounding assembly further includes an activation magnetic attractor connected to the activation grounding conductor. The second polymethyl methacrylate cured body is also coated and connected to the surface of the activation magnetic attractor. The activation magnetic attractor is magnetically located in the solution of the activation tank and is magnetically connected to the activation tank. In the activation process, the activation magnetic attractor is placed in the solution of the activation tank and magnetically connected to the activation tank, so that the activation grounding conductor is placed in the solution of the activation tank.

5. The PCB hole metallization method based on suppressing leakage current as described in claim 1, characterized in that, The copper-plating grounding conductor is positioned at the liquid level in the copper-plating cylinder; In the copper melting process, the copper melting grounding conductor is placed at the liquid level in the copper melting tank.

6. The PCB hole metallization method based on suppressing leakage current as described in claim 1, characterized in that, The copper-based grounding assembly also includes a copper-based magnetic attractor, which is connected to the copper-based grounding conductor. The third polymethyl methacrylate cured body is also coated and connected to the surface of the copper-based magnetic attractor. The copper-based magnetic attractor is located in the solution of the copper-based tank and is magnetically connected to the copper-based tank. In the copper melting process, the copper melting magnetic attractor is placed in the solution of the copper melting tank and magnetically connected to the copper melting tank, so that the copper melting grounding conductor is placed inside the copper melting tank.

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