Circuit board black hole process and circuit board

Abstract

This disclosure provides a black hole process for circuit boards and a circuit board. The aforementioned black hole process for circuit boards includes the following steps: immersing the circuit board in a first hole-forming tank for a first hole-forming treatment to improve the adhesion of the conductive material to the hole walls of the circuit board; immersing the circuit board in a first black hole tank for a first black hole treatment to form a conductive layer on the hole walls of the circuit board; immersing the circuit board in a second hole-forming tank for a second hole-forming treatment to improve the adhesion of the conductive layer to the conductive material; immersing the circuit board in a second black hole tank for a second black hole treatment to increase the thickness of the conductive layer; cleaning the circuit board to remove the chemical solution from the surface of the circuit board; and copper plating the circuit board to cover the surface of the conductive layer with a copper layer.

Description

Technical Field

[0001] This disclosure relates to the field of black hole technology for circuit boards, and in particular to a black hole process for circuit boards and a circuit board. Background Technology

[0002] The black hole process of circuit boards refers to the uniform dispersion of fine graphite or carbon black powder in a medium, namely deionized water. The surfactant in the solution keeps the uniform graphite or carbon black suspension stable and has good wetting properties, so that the graphite or carbon black can be fully adsorbed on the non-conductive hole wall surface to form a uniform, fine and firmly bonded conductive layer.

[0003] In traditional technology, the black hole process for circuit boards consists of cleaning, hole preparation, and black hole treatment. For example, Chinese patent application number CN201410322778.4 discloses a black hole horizontal production line process and black hole tank structure. The process includes the following steps: cleaning, black hole treatment one, hole preparation, black hole treatment two, micro-etching, anti-oxidation, and unloading. In order to make the graphite and carbon black powder adhere more evenly to the hole walls of the circuit board, the above patent uses two black hole treatment steps, that is, two black hole tanks are used to soak the circuit board. In actual production, black hole plating tanks need to be changed periodically to remove waste liquid and clean impurities, while new black hole plating solution is added to the new tank. To improve production efficiency, production lines typically perform tank changes simultaneously on two black hole plating tanks, adding new black hole plating solution to both. However, because the black hole plating solution in the tanks is initially static and hasn't undergone temperature and mechanical circulation, its activity is poor. This results in insufficient reaction between the circuit board and the solution, leading to uneven conductive layer formation within the circuit board holes, and ultimately, a poor copper plating finish after electroplating. Figure 2 , Figure 3 As shown, there are problems such as thin copper in the hole and broken copper in the hole.

[0004] Therefore, there is an urgent need for a black hole process for circuit boards that ensures uniform thickness of the conductive layer inside the hole and avoids copper breakage. Summary of the Invention

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a black hole process and circuit board that makes the thickness of the conductive layer inside the hole uniform and avoids copper breakage in the hole.

[0006] The purpose of this disclosure is achieved through the following technical solution:

[0007] A black hole process for circuit boards includes the following steps:

[0008] The circuit board is immersed in the first hole-forming cylinder for the first hole-forming treatment to improve the adhesion of conductive materials to the hole walls of the circuit board.

[0009] The circuit board is immersed in the first black hole tank for the first black hole treatment, so that a conductive layer is formed on the hole wall of the circuit board.

[0010] The circuit board is immersed in a second hole-forming cylinder for a second hole-forming process to improve the adhesion of the conductive layer to the conductive material.

[0011] The circuit board is immersed in a second black hole tank for a second black hole treatment to increase the thickness of the conductive layer.

[0012] The circuit board is cleaned to remove the chemical solution from its surface.

[0013] The circuit board is copper-plated so that the surface of the conductive layer is covered with a copper layer.

[0014] The process includes the following steps before performing the first hole-forming treatment on the circuit board:

[0015] The first borehole cylinder is cleaned.

[0016] The second hole-forming cylinder is cleaned. There is a first preset interval between the cleaning of the first hole-forming cylinder and the cleaning of the second hole-forming cylinder. The first preset interval is greater than N process cycles of the black hole process of the circuit board, where N is an integer greater than 1.

[0017] The circuit board is further subjected to the following steps before the first black hole treatment:

[0018] The first black hole cylinder is cleaned.

[0019] The second black hole cylinder is cleaned. There is a second preset interval between the cleaning of the first black hole cylinder and the cleaning of the second black hole cylinder. The second preset interval is greater than M process cycles of the black hole process of the circuit board, where M is an integer greater than 1.

[0020] In one embodiment, the first preset interval is 1-3 days; and / or,

[0021] The second preset interval is April to June.

[0022] In one embodiment, the first black hole cylinder is cleaned, specifically including the following steps:

[0023] Discharge 1 / 2 to 1 / 3 of the volume of old liquid from the first black hole tank and seal the old liquid. The old liquid is then introduced into the second black hole tank when cleaning the second black hole tank.

[0024] A new liquid of the same volume as the old liquid discharged is introduced into the first black hole cylinder to mix the new liquid with the old liquid.

[0025] In one embodiment, the first borehole cylinder is cleaned, specifically including the following steps:

[0026] Drain the old liquid from the first borehole cylinder;

[0027] The first borehole cylinder is cleaned.

[0028] The new liquid is introduced into the first borehole cylinder.

[0029] In one embodiment, cleaning the first borehole cylinder specifically includes the following steps:

[0030] The first borehole cylinder is flushed with an organic solvent to dissolve the dirt inside the first borehole cylinder;

[0031] The first borehole cylinder was rinsed with deionized water to remove organic solvents and dirt from it.

[0032] In one embodiment, the time for the first hole-forming process is T1, where T1 is 45s-60s; the time for the second hole-forming process is T2, where T2 is 45s-60s, and T2 is greater than T1; and / or,

[0033] The processing time for the first black hole is T3, which is 60s-90s. The processing time for the second black hole is T4, which is 60s-90s, and T4 is greater than T3.

[0034] In one embodiment, the circuit board is cleaned, specifically including the following steps:

[0035] The circuit board was rinsed with deionized water to remove any residual chemicals from its surface.

[0036] The circuit board is baked at a high temperature to evaporate the moisture on its surface.

[0037] In one embodiment, immersing the circuit board in a second hole-forming cylinder for a second hole-forming process further includes the following steps:

[0038] The ultrasonic device is activated to agitate the liquid medicine in the second orifice cylinder.

[0039] In one embodiment, the circuit board is cleaned, and the following steps are included prior to this:

[0040] The circuit board is subjected to micro-etching to roughen the surface of the conductive layer.

[0041] A circuit board is manufactured using the black hole process described in any of the above embodiments.

[0042] Compared with the prior art, this disclosure has at least the following advantages:

[0043] The above-mentioned black hole process for circuit boards involves the circuit board undergoing a first hole-forming process in a first hole-forming cylinder and a second hole-forming process in a second hole-forming cylinder. These two hole-forming processes remove impurities from the circuit board surface and improve the adhesion of carbon powder to the hole walls. Then, the circuit board undergoes a first black hole process in the first black hole cylinder and a second black hole process in the second black hole cylinder. These two black hole processes result in a more uniform conductive layer formed on the hole walls of the circuit board. Furthermore, the activity of the newly added chemical solution after cleaning differs from that of the solution before cleaning. This is because the new chemical solution is sealed in the tank and is in a static state. When the chemical solution is first added to the cleaned tank, it has not undergone temperature and production line circulation, resulting in lower activity of the newly added chemical solution compared to the solution before cleaning. The cleaning processes of the first and second hole-forming tanks have a first preset interval time, that is, the cleaning of the first and second hole-forming tanks is staggered, so that the activity of the chemical solution in the first and second hole-forming tanks is complementary, thereby making the hole-forming process of the circuit board more complete. Similarly, the cleaning processes of the first and second black hole tanks have a second preset interval time, that is, the cleaning of the first and second black hole tanks is staggered, so that the activity of the chemical solution in the first and second black hole tanks is complementary, thereby making the black hole process of the circuit board more complete, and thus making the thickness of the conductive layer formed in the hole of the circuit board more uniform, so as to avoid the problem of copper layer breakage or uneven thickness after copper plating. Attached Figure Description

[0044] 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.

[0045] Figure 1 This is a process flow diagram of a circuit board black hole process according to one embodiment;

[0046] Figure 2 A photograph of copper holes in a circuit board manufactured using traditional methods.

[0047] Figure 3 Another physical image of copper holes in a circuit board prepared using traditional methods;

[0048] Figure 4 To adopt Figure 1 The image shown is a physical photograph of the copper holes fabricated using the black hole process on the circuit board.

[0049] Figure 5 To adopt Figure 1 Another physical image of the copper vias fabricated using the black hole process on the circuit board shown. Detailed Implementation

[0050] 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.

[0051] 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.

[0052] 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.

[0053] This disclosure provides a black hole process for circuit boards, comprising the following steps: immersing the circuit board in a first hole-forming tank for a first hole-forming treatment to improve the adhesion of conductive materials to the hole walls; immersing the circuit board in a first black hole tank for a first black hole treatment to form a conductive layer on the hole walls; immersing the circuit board in a second hole-forming tank for a second hole-forming treatment to improve the adhesion of conductive materials to the conductive layer; immersing the circuit board in a second black hole tank for a second black hole treatment to increase the thickness of the conductive layer; and cleaning the circuit board to remove the conductive material. The surface is treated with a solution; copper plating is performed on the circuit board to cover the conductive layer surface with a copper layer; wherein, before performing the first hole-forming process on the circuit board, the following steps are included: cleaning the first hole-forming cylinder; cleaning the second hole-forming cylinder, with a first preset interval between the cleaning processes of the first and second hole-forming cylinders; before performing the first black hole process on the circuit board, the following steps are included: cleaning the first black hole cylinder; cleaning the second black hole cylinder, with a second preset interval between the cleaning processes of the first and second black hole cylinders.

[0054] The above-mentioned black hole process for circuit boards involves the circuit board undergoing a first hole-forming process in a first hole-forming cylinder and a second hole-forming process in a second hole-forming cylinder. These two hole-forming processes remove impurities from the circuit board surface and improve the adhesion of carbon powder to the hole walls. Then, the circuit board undergoes a first black hole process in the first black hole cylinder and a second black hole process in the second black hole cylinder. These two black hole processes result in a more uniform conductive layer formed on the hole walls of the circuit board. Furthermore, the activity of the newly added chemical solution after cleaning differs from that of the solution before cleaning. This is because the new chemical solution is sealed in the tank and is in a static state. When the chemical solution is first added to the cleaned tank, it has not undergone temperature and production line circulation, resulting in lower activity of the newly added chemical solution compared to the solution before cleaning. The cleaning processes of the first and second hole-forming tanks have a first preset interval time, that is, the cleaning of the first and second hole-forming tanks is staggered, so that the activity of the chemical solution in the first and second hole-forming tanks is complementary, thereby making the hole-forming process of the circuit board more complete. Similarly, the cleaning processes of the first and second black hole tanks have a second preset interval time, that is, the cleaning of the first and second black hole tanks is staggered, so that the activity of the chemical solution in the first and second black hole tanks is complementary, thereby making the black hole process of the circuit board more complete, and thus making the thickness of the conductive layer formed in the hole of the circuit board more uniform, so as to avoid the problem of copper layer breakage or uneven thickness after copper plating.

[0055] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0056] like Figure 1 As shown, one embodiment of the black hole process for a circuit board includes the following steps:

[0057] S100: The circuit board is immersed in the first hole-forming cylinder for the first hole-forming treatment to improve the adhesion of the conductive material to the hole wall of the circuit board.

[0058] In this embodiment, the circuit board after drilling is immersed in a first drilling tank containing a drilling liquid. The drilling liquid has a certain cleaning and leveling function. It can remove impurities and contaminants on the hole wall, providing a clean and flat surface for the deposition of conductive materials. At the same time, the drilling liquid also contains cationic surfactants to eliminate the electrostatic repulsion between the substrate surface and the negatively charged carbon colloids in the black hole liquid, promote the physical adsorption of carbon colloid particles on the hole wall, and facilitate the more uniform adhesion of conductive materials (graphite or carbon black, etc.) in the black hole liquid to the hole wall.

[0059] S200: The circuit board is immersed in the first black hole tank for the first black hole treatment, so that a conductive layer is formed on the hole wall of the circuit board.

[0060] In this embodiment, the circuit board after hole filling is immersed in a first black hole tank. The first black hole tank contains black hole liquid containing conductive substances such as graphite or carbon black. The surfactant in the black hole liquid keeps the graphite or conductive carbon black suspension stable and has good wetting properties. When the circuit board is immersed in the black hole liquid in the first black hole tank, the graphite or carbon black can be adsorbed on the non-conductive hole wall surface to initially form a relatively thin conductive layer.

[0061] S300: The circuit board is immersed in a second hole-forming cylinder for a second hole-forming process to improve the adhesion of the conductive layer to the conductive material.

[0062] In this embodiment, the circuit board after the first black hole treatment is immersed in a second hole-forming tank. The second hole-forming tank contains a hole-forming liquid, and the composition of the hole-forming liquid in the second hole-forming tank is basically the same as that in the first hole-forming tank. The concentration of cationic surfactant in the second hole-forming tank is relatively high. That is, the first hole-forming treatment is mainly for cleaning the surface of the circuit board, while the second hole-forming treatment uses a high concentration of cationic surfactant to better eliminate the electrostatic repulsion between the substrate surface and the negatively charged carbon colloid in the black hole liquid. This allows the conductive material to better adhere to the initially formed conductive layer during the subsequent second black hole treatment, thereby forming a more uniform and dense conductive layer.

[0063] S400: Immerse the circuit board in a second black hole tank for a second black hole treatment to increase the thickness of the conductive layer.

[0064] Understandably, after the first black hole treatment, the thickness and density of the conductive layer inside the hole on the circuit board do not meet the requirements. If copper plating is performed directly at this time, it is easy to cause incomplete plating or failure to plating, reducing the reliability of the black hole process. Therefore, in this embodiment, the circuit board after the second black hole treatment is immersed in a second black hole tank for a second black hole treatment. The black hole liquid in the second black hole tank has a higher concentration of graphite and surfactants than the black hole liquid in the first black hole tank. This allows the second black hole treatment to increase the thickness of the conductive layer, which was formed in the first black hole treatment, and to make the conductive layer more dense. This helps the copper layer to evenly cover the hole wall in the subsequent copper plating process.

[0065] S500: The circuit board is cleaned to remove the liquid from its surface.

[0066] In this embodiment, the circuit board after the secondary black hole treatment is cleaned to remove residual chemicals from the board surface, preventing them from entering the copper plating bath and affecting the adhesion of the copper layer. Furthermore, a high-pressure water gun can be used to rinse the board surface, allowing water to enter the holes and remove any residual chemicals.

[0067] S600: The circuit board is copper plated so that the surface of the conductive layer is covered with a copper layer.

[0068] In this embodiment, the circuit board is placed in a copper plating tank and powered on. Copper ions in the copper plating tank are adsorbed into the holes of the circuit board. The copper ions form copper monomers on the surface of the conductive layer and adhere to it, so that the holes of the circuit board are plated with a copper layer, making the conductivity of the holes of the circuit board more stable.

[0069] In one embodiment, the following steps are included before the first through-hole processing of the circuit board:

[0070] The first borehole cylinder is cleaned.

[0071] The second hole-forming cylinder is cleaned. There is a first preset interval between the cleaning of the first hole-forming cylinder and the cleaning of the second hole-forming cylinder. The first preset interval is greater than N process cycles of the black hole process of the circuit board, where N is an integer greater than 1.

[0072] It is understandable that the first and second orifice cleaning cylinders need to be cleaned after a period of use. This is because dirt and residue will accumulate inside the cylinders after long-term use, which will affect the activity and concentration of the medicine. In traditional technology, in order to improve the efficiency of cleaning, the first and second orifice cleaning cylinders are usually cleaned at the same time. However, the new medicine is sealed in the tank and is in a static state. When the new medicine is introduced into the cleaned orifice cleaning cylinder, it has not been circulated by temperature and production line, resulting in relatively low activity of the medicine. That is, the activity of the newly introduced medicine needs to reach its peak after a period of time. If the first and second orifice cleaning cylinders are cleaned at the same time, the activity of the medicine in the first and second orifice cleaning cylinders will be in a low state. Therefore, in this embodiment, the cleaning processes of the first and second hole-forming cylinders are performed at a first preset interval. This means the cleaning of the first and second hole-forming cylinders is staggered. For example, the first hole-forming cylinder is cleaned first, at which point the activity of the chemical solution in the first cylinder is relatively low. However, the second hole-forming cylinder is not cleaned at this time, meaning the activity of the chemical solution in the second cylinder is relatively high. This allows the chemical activities of the first and second hole-forming processes to complement each other, enabling the circuit board to complete the hole-forming process normally. After the first preset interval, the second hole-forming cylinder is cleaned. At this time, the activity of the chemical solution in the first hole-forming cylinder is relatively higher than that in the second cylinder, resulting in complementary chemical activities between the first and second hole-forming processes, allowing the circuit board to complete the hole-forming process normally. Furthermore, the first preset interval is greater than N process cycles of the black hole process on the circuit board, where N is an integer greater than 1, indicating that the interval between the cleaning of the first and second hole-forming cylinders is greater than the time required for the black hole process on the circuit board.

[0073] In one embodiment, the circuit board is further subjected to the first black hole treatment prior to the following steps:

[0074] The first black hole cylinder is cleaned.

[0075] The second black hole cylinder is cleaned. There is a second preset interval between the cleaning of the first black hole cylinder and the cleaning of the second black hole cylinder. The second preset interval is greater than M process cycles of the black hole process of the circuit board, where M is an integer greater than 1.

[0076] It is understandable that the first and second black hole tanks need to be cleaned after a period of use. This is because the black hole tanks will also accumulate dirt and residue after long-term use, which will affect the concentration and activity of the liquid. In traditional technology, in order to improve the efficiency of cleaning, the first and second black hole tanks are usually cleaned at the same time. However, the new black hole liquid is in a static state when it is sealed in the tank. When the new black hole liquid is introduced into the cleaned black hole tank, it has not been circulated by temperature and production line, resulting in relatively low activity of the black hole liquid at this time. That is, the activity of the newly introduced black hole liquid needs to reach its peak after a period of time. If the first and second black hole tanks are cleaned at the same time, the activity of the black hole liquid in the first and second black hole tanks will be in a low state. Therefore, in this embodiment, the cleaning processes of the first and second black hole cylinders have a second preset interval time. This means the cleaning of the first and second black hole cylinders is staggered. For example, the first black hole cylinder is cleaned first, at which point the activity of the black hole solution in the first cylinder is relatively low. However, the second black hole cylinder is not cleaned at this time, meaning the activity of the black hole solution in the second cylinder is relatively high. This allows the black hole solutions from the first and second black hole treatments to complement each other, enabling the circuit board to complete the black hole treatment normally. After the second preset interval time, the second black hole cylinder is cleaned. By this time, the activity of the solution in the first black hole cylinder has reached its peak after a period of circulation, meaning the activity of the black hole solution in the first cylinder is relatively high. This again allows the black hole solutions from the first and second black hole treatments to complement each other, enabling the circuit board to complete the black hole treatment normally. Furthermore, the second preset interval time is greater than N process cycles of the circuit board black hole process, where N is an integer greater than 1, indicating that the interval between cleaning the first and second black hole cylinders is greater than the time required for the circuit board to perform the black hole process.

[0077] The above-mentioned black hole process for circuit boards involves the circuit board undergoing a first hole-forming process in a first hole-forming cylinder and a second hole-forming process in a second hole-forming cylinder. These two hole-forming processes remove impurities from the circuit board surface and improve the adhesion of carbon powder to the hole walls. Then, the circuit board undergoes a first black hole process in the first black hole cylinder and a second black hole process in the second black hole cylinder. These two black hole processes result in a more uniform conductive layer formed on the hole walls of the circuit board. Furthermore, the activity of the newly added chemical solution after cleaning differs from that of the solution before cleaning. This is because the new chemical solution is sealed in the tank and is in a static state. When the chemical solution is first added to the cleaned tank, it has not undergone temperature and production line circulation, resulting in lower activity of the newly added chemical solution compared to the solution before cleaning. The cleaning processes of the first and second hole-forming tanks have a first preset interval time, that is, the cleaning of the first and second hole-forming tanks is staggered, so that the activity of the chemical solution in the first and second hole-forming tanks is complementary, thereby making the hole-forming process of the circuit board more complete. Similarly, the cleaning processes of the first and second black hole tanks have a second preset interval time, that is, the cleaning of the first and second black hole tanks is staggered, so that the activity of the chemical solution in the first and second black hole tanks is complementary, thereby making the black hole process of the circuit board more complete, and thus making the thickness of the conductive layer formed in the hole of the circuit board more uniform, so as to avoid the problem of copper layer breakage or uneven thickness after copper plating.

[0078] In one embodiment, the first preset interval is 1 to 3 days. It can be understood that the first preset interval is 1 to 3 days, meaning that the second drilling cylinder is cleaned 1 to 3 days after the first drilling cylinder is cleaned. This ensures that the solution in the first drilling cylinder has high activity after being circulated for a preset time. At this point, the second drilling cylinder is replaced, thus allowing the solutions in the first and second drilling cylinders to complement each other, thereby enabling the circuit board to complete the drilling process normally.

[0079] In one embodiment, the second preset interval is 4 to 6 months. It is understood that the second preset interval of 4 to 6 months means that the second black hole tank is cleaned 4 to 6 months after the first black hole tank is cleaned. This allows the black hole solution in the second black hole tank to have higher activity after being circulated for a preset time. At this point, the second black hole tank is replaced, thus allowing the black hole solutions in the first and second black hole tanks to complement each other, enabling the circuit board to complete the black hole treatment normally.

[0080] In one embodiment, the first black hole cylinder is cleaned, specifically including the following steps:

[0081] Discharge 1 / 2 to 1 / 3 of the volume of old liquid from the first black hole tank and seal the old liquid. The old liquid is then introduced into the second black hole tank when cleaning the second black hole tank.

[0082] A new liquid of the same volume as the old liquid discharged is introduced into the first black hole cylinder to mix the new liquid with the old liquid.

[0083] Understandably, if the old liquid in the first black hole tank is completely drained during the cleaning process, the amount of medicine used will increase, leading to increased costs. In this embodiment, 1 / 2 to 1 / 3 of the volume of the old liquid in the first black hole tank is drained and sealed in a storage tank. This old liquid is used to purge the second black hole tank during the cleaning process. This is because the composition of the medicine in the first and second black hole tanks is basically the same. For the cleaning process of the second black hole tank, since 1 / 2 to 1 / 3 of the volume of the old liquid has been purged into the second black hole tank, the second black hole tank only needs to be purged with the corresponding amount of new liquid to mix with the old liquid. That is, the second black hole tank does not need to be completely purged with new liquid, thus reducing the amount of medicine used when cleaning the second black hole tank. Furthermore, regarding the cleaning process of the first black hole tank, since 1 / 2 to 1 / 3 of the volume of old liquid has been discharged from the first black hole tank, only a corresponding volume of new liquid needs to be introduced to mix with the old liquid in the first black hole tank. That is, it is not necessary to completely introduce new liquid into the first black hole tank, reducing the amount of chemicals used during the cleaning process. Simultaneously, since 1 / 2 to 2 / 3 of the volume of old liquid remains in the first black hole tank, and this old liquid has been circulated through temperature and the production line, its activity is relatively high. When this old liquid mixes with the less active new liquid, it forms the black hole liquid in the first black hole tank. Compared to the first black hole tank that is completely introduced with new liquid, the black hole liquid formed by the mixture of the remaining old liquid and new liquid has relatively high activity. In this way, the activity of the chemical solution in the first black hole tank can be improved, while also saving the amount of chemical solution used, reducing production costs, and making the treatment effect of the first black hole better. Furthermore, during the cleaning process of the second black hole tank, a portion of the old liquid can be drained and used to purge the first black hole tank during cleaning. This further reduces the amount of new liquid being introduced into the first black hole tank during cleaning. Through continuous circulation of the old liquid in both the first and second black hole tanks, the amount of new liquid used can be reduced, while simultaneously maintaining the activity of the liquid in both tanks after cleaning. Even further, to facilitate cleaning of the first black hole tank, the old liquid can be circulated into a temporary storage tank. At this point, all the liquid in the first black hole tank has been drained. The tank walls are then cleaned with organic solvents and water to remove any residue. The old liquid from the temporary storage tank is then circulated back into the first black hole tank, along with a corresponding volume of new liquid, to create a new black hole liquid within the tank.

[0084] In one embodiment, the first borehole cylinder is cleaned, specifically including the following steps:

[0085] Drain the old liquid from the first borehole cylinder;

[0086] The first borehole cylinder is cleaned.

[0087] The new liquid is introduced into the first borehole cylinder.

[0088] In this embodiment, the old liquid in the first sizing tank is extracted using a pump, and then the tank is rinsed with deionized water to remove dirt and residue. Finally, new sizing solution is pumped into the first sizing tank to complete the cleaning process. Furthermore, the cleaning processes for the second sizing tank, the first black hole tank, and the second black hole tank are the same as those for the first sizing tank, and will not be described again here.

[0089] In one embodiment, cleaning the first borehole cylinder specifically includes the following steps:

[0090] The first borehole cylinder is flushed with an organic solvent to dissolve the dirt inside the first borehole cylinder;

[0091] The first borehole cylinder was rinsed with deionized water to remove organic solvents and dirt from it.

[0092] Understandably, since the residues and dirt inside the first borehole cleaning tank mainly consist of resin, grease, and metal shavings, these residues and dirt adhere to the tank wall. Simply rinsing with deionized water may not completely remove them. In this embodiment, an organic solvent (such as hydrocarbons, alcohols, or other chemical reagents) is first added to the tank. Organic solvents have strong dissolving power and can dissolve the grease, resin, and other dirt inside the borehole cleaning tank. Then, the first borehole cleaning tank is high-pressure rinsed with deionized water to remove both the dirt and the organic solvent, resulting in a more thorough cleaning of the first borehole cleaning tank.

[0093] In one embodiment, the time for the first hole-forming process is T1, where T1 is 45s-60s, and the time for the second hole-forming process is T2, where T2 is 45s-60s, and T2 is greater than T1.

[0094] In this embodiment, the time T1 for the first hole-forming process is 45s-60s, and the time T2 for the second hole-forming process is 45s-60s, with T2 being greater than T1. This is because a thinner conductive layer is formed after the first black hole treatment. The longer time for the second hole-forming process is to allow more cations in the hole-forming liquid to gather on the conductive layer and the hole wall, thereby improving the adhesion of the conductive material. As a result, the conductive layer formed after the second black hole treatment is thicker, more uniform, and has better density.

[0095] In one embodiment, the processing time for the first black hole is T3, which is 60s-90s, and the processing time for the second black hole is T4, which is 60s-90s, and T4 is greater than T3.

[0096] In this embodiment, the processing time T3 for the first black hole is 60s-90s, and the processing time T4 for the second black hole is 60s-90s, with T4 being greater than T3. This allows the conductive material to better accumulate on the hole wall of the circuit board during the second black hole processing, resulting in a thicker, more uniform, and denser conductive layer after the second black hole processing.

[0097] In one embodiment, the circuit board is cleaned, specifically including the following steps:

[0098] The circuit board was rinsed with deionized water to remove any residual chemicals from its surface.

[0099] The circuit board is baked at a high temperature to evaporate the moisture on its surface.

[0100] In this embodiment, the circuit board is rinsed with deionized water using a high-pressure water gun so that the water flow can enter the holes of the circuit board to remove the residual liquid inside the holes. After rinsing, the circuit board is dried at high temperature using a drying device so that the moisture on the surface of the circuit board evaporates quickly.

[0101] In one embodiment, immersing the circuit board in a second hole-forming cylinder for a second hole-forming process further includes the following steps:

[0102] The ultrasonic device is activated to agitate the liquid medicine in the second orifice cylinder.

[0103] Understandably, in order to ensure that the solution in the second hole-forming cylinder can fully contact the hole wall of the circuit board during the second hole-forming process, ultrasonic equipment is used to vibrate the solution in the second hole-forming cylinder, so that the solution forms turbulence in the second hole-forming cylinder, thereby allowing the solution to fully contact and wet the hole wall, thus making the second hole-forming process more effective.

[0104] In one embodiment, the circuit board is immersed in a second black hole tank for a second black hole treatment to increase the thickness of the conductive layer, and the process further includes the following steps:

[0105] The ultrasonic device is activated to vibrate the liquid medicine in the second black hole cylinder.

[0106] Understandably, in order to make the conductive layer more uniform and denser after the second black hole treatment, an ultrasonic device is activated when the circuit board is immersed in the second black hole tank to vibrate the black hole liquid in the tank. This causes the black hole liquid to form turbulence in the tank, which in turn allows the black hole liquid to make more sufficient contact with the hole wall, thus making the second black hole treatment more effective.

[0107] In one embodiment, the circuit board is cleaned, and the following steps are included prior to this:

[0108] The circuit board is subjected to micro-etching to roughen the surface of the conductive layer.

[0109] Understandably, in order to ensure that copper adheres better to the conductive layer during the copper plating process, in this embodiment, an etching solution is used to perform a micro-etching operation on the circuit board. That is, the etching solution will etch the surface of the conductive layer, thereby increasing the surface roughness of the conductive layer and thus improving the bonding force between the conductive layer and the copper layer, so that the copper adheres better to the conductive layer to form a copper layer with more uniform thickness and better density.

[0110] Understandably, the thickness of the conductive layer formed inside the circuit board holes needs to be within a preset range. This is because if the conductive layer is too thin, the copper layer will adhere poorly to the conductive layer in the subsequent copper plating process, resulting in a thinner copper layer and consequently poor conductivity inside the circuit board holes. Conversely, if the conductive layer is too thick, the resistance inside the holes will be too high, which will also affect the conductivity. Therefore, to achieve a more suitable thickness of the conductive layer inside the holes, in one embodiment, the circuit board is immersed in a second black hole tank for a second hole-forming process, preceded by the following steps:

[0111] Obtain the first thickness of the conductive layer inside the circuit board hole;

[0112] The first thickness of the conductive layer is matched with a first preset thickness;

[0113] When the first thickness of the conductive layer is greater than or equal to the first preset thickness, the concentration of the black hole liquid in the second black hole treatment is reduced, and the temperature of the black hole liquid in the second black hole treatment is increased.

[0114] In this embodiment, the first thickness is the thickness of the conductive layer initially formed after the first black hole treatment of the circuit board, and the first preset thickness is a suitable range of thickness values ​​preset after the first black hole treatment of the circuit board. If the first thickness is not within the first preset thickness range, it will affect the thickness of the conductive layer after the second black hole treatment, and thus affect the conductivity of the hole in the circuit board. Specifically, the thickness of the conductive layer inside the circuit board hole is first measured to obtain a first thickness. This first thickness is then matched with a first preset thickness. When the first thickness is greater than or equal to the first preset thickness, it indicates that the conductive layer thickness after the first black hole treatment is relatively high. In this case, the reaction parameters of the second black hole treatment need to be adjusted so that the final thickness of the conductive layer is within the preset range. This is achieved by reducing the concentration of the black hole liquid in the second black hole treatment, i.e., reducing the content of graphite and carbon black in the black hole liquid. This reduces the amount of graphite and carbon black accumulating in the circuit board hole during the second black hole treatment. Simultaneously, the temperature of the black hole liquid in the second black hole treatment is increased. This is because the active temperature of the black hole liquid is generally 20℃~25℃. Increasing the temperature of the black hole liquid will reduce its activity. This results in a lower conductive layer thickness after the second black hole treatment, meaning that the conductive layer thickness after both the first and second black hole treatments is within the preset range, thus improving the conductivity inside the circuit board hole.

[0115] In another embodiment, when the first thickness of the conductive layer is less than the first preset thickness, the concentration of the black hole liquid in the second black hole treatment is increased, and the temperature of the black hole liquid in the second black hole treatment is decreased.

[0116] In this embodiment, when the first thickness of the conductive layer is less than the first preset thickness, it indicates that the thickness of the conductive layer in the first black hole treatment is low, and the reaction parameters of the second black hole treatment need to be adjusted to increase the thickness of the conductive layer formed in the second black hole treatment. Specifically, by increasing the concentration of the black hole liquid in the second black hole treatment, that is, increasing the graphite and carbon black content of the black hole liquid, the amount of graphite and carbon black accumulating in the circuit board holes during the second black hole treatment increases. At the same time, the temperature of the black hole liquid in the second black hole treatment is decreased to keep the temperature of the black hole liquid lower, thereby increasing the activity of the black hole liquid and thus increasing the thickness of the conductive layer formed in the second black hole treatment. This ensures that the conductive layers after the first and second black hole treatments are within the preset range.

[0117] Furthermore, to ensure that the conductive layer thickness after the second black hole treatment is within a preset range, resulting in good conductivity and low resistance within the circuit board holes, in one embodiment, the circuit board is immersed in a second black hole tank for a second hole-forming treatment, followed by the following steps:

[0118] Obtain the second thickness of the conductive layer inside the circuit board hole;

[0119] Match the second thickness of the conductive layer with the second preset thickness.

[0120] When the second thickness is greater than or equal to the second preset thickness, the concentration of the etching solution in the micro-etching operation is increased, and the reaction time of the micro-etching operation is reduced.

[0121] In this embodiment, the second thickness refers to the combined thickness of the conductive layer after the first and second black hole treatments. The second preset thickness is a pre-defined range of suitable thickness values ​​for the conductive layer inside the circuit board hole after the black hole treatment. It is understood that if the second thickness is less than the second preset thickness, it indicates that the formed conductive layer thickness is low, resulting in poor conductivity within the circuit board hole. Conversely, if the second thickness is greater than the second preset thickness, it indicates that the formed conductive layer thickness is high, resulting in high resistance within the circuit board hole. Specifically, the thickness of the conductive layer inside the circuit board hole is first detected to obtain the second thickness. Then, the second thickness is matched with the second preset thickness. When the second thickness is greater than or equal to the second preset thickness, it indicates that the formed conductive layer thickness is high. At this point, the concentration of the etching solution in the micro-etching operation is increased. The etching solution is used to etch the conductive layer, roughening the surface of the conductive layer. Increasing the concentration of the etching solution enhances the etching effect on the conductive layer, thus increasing the thickness of the etched conductive layer and consequently reducing the thickness of the etched conductive layer, so that the final conductive layer thickness of the circuit board is within the second preset thickness range. Furthermore, it is necessary to reduce the reaction time of the etching operation. This is because increasing the concentration of the etching solution may affect the copper layer and dry film on the circuit board surface. If the etching operation time is too long, the etching solution will erode the copper layer and dry film on the circuit board surface, thereby affecting the circuit on the circuit board surface. By reducing the reaction time of the etching operation, the etching solution can erode the conductive layer without affecting the circuit board surface.

[0122] This application also provides a circuit board manufactured using the black hole process described in any of the above embodiments.

[0123] Compared with the prior art, this disclosure has at least the following advantages:

[0124] The above-mentioned black hole process for circuit boards involves the circuit board undergoing a first hole-forming process in a first hole-forming cylinder and a second hole-forming process in a second hole-forming cylinder. These two hole-forming processes remove impurities from the circuit board surface and improve the adhesion of carbon powder to the hole walls. Then, the circuit board undergoes a first black hole process in the first black hole cylinder and a second black hole process in the second black hole cylinder. These two black hole processes result in a more uniform conductive layer formed on the hole walls of the circuit board. Furthermore, the activity of the newly added chemical solution after cleaning differs from that of the solution before cleaning. This is because the new chemical solution is sealed in the tank and is in a static state. When the chemical solution is first added to the cleaned tank, it has not undergone temperature and production line circulation, resulting in lower activity of the newly added chemical solution compared to the solution before cleaning. The cleaning processes of the first and second hole-forming tanks have a first preset interval time, that is, the cleaning of the first and second hole-forming tanks is staggered, so that the activity of the chemical solution in the first and second hole-forming tanks is complementary, thereby making the hole-forming process of the circuit board more complete. Similarly, the cleaning processes of the first and second black hole tanks have a second preset interval time, that is, the cleaning of the first and second black hole tanks is staggered, so that the activity of the chemical solution in the first and second black hole tanks is complementary, thereby making the black hole process of the circuit board more complete, and thus making the thickness of the conductive layer formed in the hole of the circuit board more uniform, so as to avoid the problem of copper layer breakage or uneven thickness after copper plating.

[0125] 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 invention 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 black hole process for circuit boards, characterized in that, Includes the following steps: The circuit board is immersed in the first hole-forming cylinder for the first hole-forming treatment to improve the adhesion of conductive materials to the hole walls of the circuit board. The circuit board is immersed in the first black hole tank for the first black hole treatment, so that a conductive layer is formed on the hole wall of the circuit board. The circuit board is immersed in a second hole-forming cylinder for a second hole-forming process to improve the adhesion of the conductive layer to the conductive material. The circuit board is immersed in a second black hole tank for a second black hole treatment to increase the thickness of the conductive layer. The circuit board is cleaned to remove the chemical solution from its surface; The circuit board is copper-plated so that the surface of the conductive layer is covered with a copper layer. The process includes the following steps before performing the first hole-forming treatment on the circuit board: The first borehole cylinder is cleaned. The second hole-forming cylinder is cleaned. There is a first preset interval between the cleaning of the first hole-forming cylinder and the cleaning of the second hole-forming cylinder. The first preset interval is greater than N process cycles of the black hole process of the circuit board, where N is an integer greater than 1. The circuit board is further subjected to the following steps before the first black hole treatment: The first black hole cylinder is cleaned. The second black hole cylinder is cleaned. There is a second preset interval between the cleaning of the first black hole cylinder and the cleaning of the second black hole cylinder. The second preset interval is greater than M process cycles of the black hole process of the circuit board, where M is an integer greater than 1.

2. The black hole process for circuit boards according to claim 1, characterized in that, The first preset interval is 1-3 days; and / or, The second preset interval is April to June.

3. The black hole process for circuit boards according to claim 1, characterized in that, The cleaning process for the first black hole cylinder specifically includes the following steps: Discharge 1 / 2 to 1 / 3 of the volume of old liquid from the first black hole tank and seal the old liquid. The old liquid is then introduced into the second black hole tank when cleaning the second black hole tank. A new liquid of the same volume as the old liquid discharged is introduced into the first black hole cylinder to mix the new liquid with the old liquid.

4. The black hole process for circuit boards according to claim 1, characterized in that, The cleaning process for the first borehole cylinder specifically includes the following steps: Drain the old liquid from the first borehole cylinder; The first borehole cylinder is cleaned. The new liquid is introduced into the first borehole cylinder.

5. The black hole process for circuit boards according to claim 4, characterized in that, The cleaning operation for the first borehole cylinder specifically includes the following steps: The first borehole cylinder is flushed with an organic solvent to dissolve the dirt inside the first borehole cylinder; The first borehole cylinder was rinsed with deionized water to remove organic solvents and dirt from it.

6. The black hole process for circuit boards according to claim 1, characterized in that, The time for the first hole-forming process is T1, where T1 is 45s-60s; the time for the second hole-forming process is T2, where T2 is 45s-60s, and T2 is greater than T1; and / or, The processing time for the first black hole is T3, which is 60s-90s. The processing time for the second black hole is T4, which is 60s-90s, and T4 is greater than T3.

7. The black hole process for circuit boards according to claim 1, characterized in that, The circuit board is cleaned, specifically including the following steps: The circuit board was rinsed with deionized water to remove any residual chemicals from its surface. The circuit board is baked at a high temperature to evaporate the moisture on its surface.

8. The black hole process for circuit boards according to claim 1, characterized in that, The circuit board is immersed in a second hole-forming cylinder for a second hole-forming process, which also includes the following steps: The ultrasonic device is activated to agitate the liquid medicine in the second orifice cylinder.

9. The black hole process for circuit boards according to claim 1, characterized in that, Before cleaning the circuit board, the following steps are also included: The circuit board is subjected to micro-etching to roughen the surface of the conductive layer.

10. A circuit board, characterized in that, The circuit board is prepared using the black hole process described in any one of claims 1 to 9.

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