Electroplating method for blind through hole of PCB with ultrasonic assembly

Abstract

The invention discloses an electroplating method for a PCB blind through hole with an ultrasonic assembly. An ultrasonic vibration rod clamp, an ultrasonic vibration rod, a heat preservation layer, a temperature controller, an electroplating anode, a circulating pump, an electroplating bath, an ultrasonic control module, a temperature controller control module and a power source are included. The power supply is connected with the electroplating anode, the temperature controller control module, the circulating pump and the ultrasonic control module and is used for providing electric energy required by PCB electroplating; an ultrasonic vibration rod in the device is fixed through a clamp and used for generating ultrasonic waves, an electroplating bath is used for containing an electroplating anode and an electroplating cathode, and a circulating pump is responsible for circulating flowing of electroplating liquid. According to the method, uniform distribution of all components in the electroplating liquid is promoted through the effect of ultrasonic waves, the uniformity of an electroplated layer is remarkably improved, bubbles generated in the electrolysis process are effectively reduced, finally, the overall electroplating quality of PCB products is improved, and the refined production requirement is met.

Description

Technical Field

[0001] The invention discloses a PCB blind through hole electroplating method with an ultrasonic component, belonging to the field of electroplating technology. Background Art

[0002] PCB is the main carrier for the installation and insertion of electronic components. The quality of its production directly affects the reliability of the final electronic products. PCB blind via metallization can realize the interconnection of any layer of PCB, thereby reducing delays and improving work efficiency. PCB blind via metallization is generally achieved through electroplating, so electroplating is a key link in PCB manufacturing. It requires the plating of metal copper with good conductivity in the hole. High-density and high-precision PCBs have higher requirements on the thickness and uniformity of the copper plating of blind vias.

[0003] In the electroplating process, chemical copper deposition is usually carried out first to form a conductive layer on the surface of the PCB, and then the electroplating process is carried out. However, various process defects often occur during the electroplating process, such as voids in the holes, irregular plating, and no copper in the holes. There are many reasons for this, such as poor circulation of the plating solution in the holes, which leads to a decrease in the concentration of copper ions in the holes and a thinner copper plating layer; bubbles appear in the holes during the electroplating process and cannot be discharged, hindering the deposition of the plating layer; the current density is too large, resulting in too fast deposition speed at the hole mouth, making ion exchange in the hole difficult, affecting the quality of the plating layer. At present, a fast, simple, and low-cost PCB blind through-hole electroplating process is still being explored.

[0004] The price of metallic copper is currently getting higher and higher, which in turn leads to higher and higher PCB production costs. The precision requirements of PCBs are also getting higher and higher. Reducing production costs while ensuring the quality of PCB products is still the primary factor that manufacturers need to consider. Summary of the invention

[0005] In view of the difficulty of ion exchange in the hole and the generation of bubbles in the hole, the present invention provides a PCB blind through hole electroplating method with an ultrasonic component, which is used to improve the uniformity and filling effect of the electroplating layer of the PCB blind through hole. The method uses the synergistic effect of the ultrasonic component, the plating solution circulation system and the temperature control system to fully stir and evenly distribute the plating solution during the electroplating process, thereby enhancing the density and adhesion of the electroplating layer. The method solves the problem of poor blind through hole plating effect caused by ultrasonic attenuation in the traditional electroplating process, has higher electroplating efficiency and plating quality, and is particularly suitable for the optimization of the electroplating process of blind through holes with different aspect ratios.

[0006] The technical solution of the present invention is: a PCB blind through hole electroplating method with an ultrasonic component, comprising the following steps:

[0007] (1) Obtain a PCB board with a blind through hole having an aspect ratio of 2:1 to 16:1;

[0008] (2) Using chemical copper deposition process to deposit a conductive layer with a thickness of 0.2 to 3 μm on the PCB surface;

[0009] (3) starting the power supply, placing the PCB with the conductive layer in the electroplating tank, starting the temperature controller, connecting the temperature controller control module to the power supply, setting the temperature controller heating device at the bottom of the electroplating tank, and the temperature acquisition device of the temperature controller inside the electroplating tank to control the temperature in the tank between 19 and 25° C.; starting the circulation pump, connecting the circulation pump to the power supply, sucking the plating solution from the outlet of the electroplating tank and pumping it in from the inlet to form a liquid circulation;

[0010] (4) Connect the anode and cathode of the power supply to the anode plate and PCB board respectively, so that the electroplating process is maintained at 0.5~2A / dm 2 The current density is 2.14V.

[0011] (5) starting the ultrasonic fixture device, which is connected to the ultrasonic control module, adjusting the ultrasonic vibrator to a first preset position, starting the ultrasonic vibrator to emit an ultrasonic frequency of 40 kHz, and connecting the ultrasonic vibrator to the ultrasonic control module and a power supply, and continuing the electroplating for 1 to 4 hours;

[0012] (6) After 0.5 hours of electroplating, the ultrasonic fixture moves the ultrasonic vibrator to the second preset position and continues to emit ultrasonic waves. After another 0.5 hours, the ultrasonic vibrator returns to the first preset position, and this cycle is repeated until the electroplating is completed.

[0013] This method achieves uniform distribution of the plating solution and improves the uniformity of the electroplating layer of the PCB blind through-hole by adjusting the position of the ultrasonic vibrator and the action of ultrasonic waves.

[0014] Specifically, the electroplating method of the present invention ensures that the plating solution is evenly distributed during the electroplating process and effectively improves the quality of electroplating by comprehensively utilizing a circulating pump and an ultrasonic device. The fluidity of the plating solution in the electroplating tank directly affects the electroplating effect, so the present invention first uses a circulating pump to cause the plating solution to flow continuously. This flow helps to maintain a uniform distribution of the plating solution during the electroplating process, avoiding the phenomenon of excessively high or low local concentrations, thereby ensuring that the blind through holes and the surface of the PCB can be evenly plated. The circulating pump forms a continuous liquid circulation by sucking the plating solution at the bottom of the plating tank and pushing it back into the tank, which can promote the uniformity of the plating solution and further ensure the stability of the temperature, composition and concentration during the electroplating process.

[0015] In addition, the traditional electroplating method only relies on liquid flow or mechanical stirring to achieve the uniformity of the plating solution, but this is often difficult to achieve the desired effect, especially in the electroplating inside a complex structure such as a blind through hole. Therefore, the present invention further enhances the stirring effect of the plating solution by emitting high-frequency ultrasonic waves through an ultrasonic device. The high-frequency vibration of the ultrasonic wave can excite the oscillation of tiny bubbles in the plating solution and produce local high-speed flow. This phenomenon is called the "ultrasonic cavitation" effect. Through the cavitation effect of the ultrasonic wave, the bubbles in the blind through hole can be more effectively removed, and the formation of bubbles can be avoided to affect the uniformity and quality of the electroplated layer. At the same time, the cavitation effect of the ultrasonic wave helps to improve the transmission efficiency of the plating solution, making the coating more uniform in the blind through hole.

[0016] In the present invention, the ultrasonic vibrator is vertically inserted into the electroplating tank, and the design maximizes the effect of ultrasonic energy. The way the ultrasonic vibrator is inserted allows the energy of the ultrasonic wave to be quickly and efficiently transmitted in the electroplating solution, reducing the loss of energy during the transmission process. The vertical insertion method helps to concentrate the ultrasonic energy in the electroplating tank, ensuring that each position can receive sufficient ultrasonic energy, thereby improving the electroplating effect.

[0017] In order to further optimize the effect of ultrasound, the present invention designs an adjustable function of the ultrasonic vibrator. The ultrasonic vibrator is fixed by a special clamp and can perform reciprocating motion in the z direction and the x direction during the electroplating process. This design allows the ultrasonic vibrator to flexibly adjust its position according to the specific position, density and distribution of the blind through holes of the PCB workpiece. By continuously adjusting the position of the ultrasonic vibrator, it can be ensured that each blind through hole can receive the best ultrasonic energy during the electroplating process, thereby promoting the uniform distribution of the electroplating solution in the hole. In particular, when the density of the blind through holes is high or the position is more complex, the position adjustment of the ultrasonic vibrator can ensure that the ultrasonic wave can penetrate into every corner inside the hole, avoiding the phenomenon of uneven electroplating due to insufficient ultrasonic energy.

[0018] This design can also dynamically adjust the ultrasonic emission position according to the changes in the electroplating progress and the actual situation of the blind through hole, thereby avoiding the shortcomings of the traditional method that the electroplating effect is affected by the attenuation of ultrasonic energy. As the ultrasonic vibrator moves, the range of ultrasonic action is expanded, further improving the stirring uniformity of the electroplating solution and ensuring the electroplating quality of the blind through hole.

[0019] Furthermore, the ultrasonic device plays a vital role in the electroplating process of the present invention. The ultrasonic vibrator can generate high-frequency vibrations in the electroplating solution, which can effectively break the bubbles in the electroplating solution and promote the uniform flow of the electroplating solution. The ultrasonic vibrator emits ultrasonic waves at a specific position and reciprocates between multiple preset positions. This process plays a vital role in the distribution of the electroplating solution in the blind through hole.

[0020] Specifically, the reciprocating motion of the ultrasonic vibrator ensures the uniform distribution of ultrasonic energy in the electroplating tank. By moving back and forth between different preset positions, the ultrasonic wave can apply the same intensity of energy at each position in the electroplating tank, which is crucial to improving the stirring effect of the electroplating solution. Especially in the special structure of blind through holes, since the interior of blind through holes is usually narrow and complex, bubbles are easy to accumulate and affect the uniformity of the electroplating layer. The movement of the ultrasonic vibrator can effectively eliminate the bubbles generated in the hole, prevent the bubbles from blocking the normal flow of the electroplating solution, and ensure that the electroplating solution can smoothly enter the hole and fully contact the surface.

[0021] In addition, the movement of the ultrasonic vibrator and the emission frequency and emission duration are all adjusted by the ultrasonic controller. By controlling the frequency of the ultrasonic vibrator, the wavelength of the emitted ultrasonic wave can be optimized, thereby ensuring that the energy distribution of the ultrasonic wave can reach the optimal state under different electroplating conditions. For example, when dealing with more complex blind through hole structures, higher frequencies and longer emission durations may be required to ensure that the ultrasonic wave can penetrate deep into the hole and fully exert its effect. For simpler electroplating processes, lower frequencies and shorter emission durations are sufficient to complete the task. The addition of an ultrasonic controller allows this process to be precisely controlled. It can not only flexibly adjust the parameters of the ultrasonic wave according to actual needs, but also make corresponding adjustments according to the different stages of the electroplating process to ensure the stability and efficiency of the entire electroplating process.

[0022] Through this precise control, the present invention can flexibly adapt to different electroplating requirements. Whether it is processing complex blind through hole structures or large-area surface electroplating, the movement and frequency adjustment of the ultrasonic vibrator can provide the best electroplating effect. In addition, the ultrasonic controller can also monitor the ultrasonic emission during the electroplating process in real time to ensure that the effect of the ultrasonic wave is always kept within the predetermined range during the entire process, thereby avoiding uneven electroplating effects or energy waste caused by excessively high or low frequencies.

[0023] In short, the reciprocating motion of the ultrasonic vibrator and the precise adjustment of its emission parameters not only effectively improve the distribution of the plating solution in the blind via hole, but also greatly improve the uniformity of the plating layer, eliminate the influence of bubbles in the blind via hole, and thus improve the flexibility and adaptability of the entire electroplating process. Through the application of this technology, the quality of electroplating has been significantly improved, especially when dealing with complex or high-density blind via holes, the effect of ultrasound makes the electroplating effect more ideal, further meeting the needs of high-precision electroplating process.

[0024] Furthermore, in order to ensure the temperature stability during the electroplating process, the present invention adds a temperature controller and a heat preservation layer to ensure that the electroplating solution is always kept within the ideal temperature range during the entire electroplating process, thereby improving the electroplating effect. The temperature of the electroplating solution has an important influence on the ion exchange rate, the quality of the coating and the electroplating efficiency during the electroplating process, so the present invention pays special attention to the accuracy of temperature control.

[0025] First, the temperature controller heats the plating solution in the plating tank through its bottom heating device. The heating device can quickly and evenly heat the plating solution to the required temperature, and monitor the temperature change of the plating solution in real time through the temperature acquisition module of the temperature controller. The temperature controller and the temperature acquisition module cooperate with each other to make timely adjustments when the temperature deviates from the predetermined range to ensure that the temperature of the plating solution is maintained within a stable range of 19 to 25°C. This temperature range has an ideal promoting effect on the ion exchange rate in the plating solution, which helps to improve the quality and efficiency of electroplating. Within this temperature range, the ions in the plating solution can be exchanged at a faster rate, thereby accelerating the electroplating process and promoting the uniform deposition of the electroplating layer.

[0026] In addition, the addition of the insulation layer further enhances the temperature stability. The insulation layer can effectively reduce the interference of the external environment on the temperature in the electroplating tank, prevent the temperature from changing drastically due to external temperature fluctuations, and thus ensure the continuous stability of the plating solution temperature. By isolating the loss of heat, the insulation layer not only maintains the constant temperature environment of the electroplating solution during the heating stage, but also makes the temperature distribution in the electroplating tank more uniform, reducing the occurrence of local temperature differences. This design can effectively prevent problems such as uneven quality or thin plating caused by uneven temperature, ensuring that the plating layer of each part can achieve consistent thickness and quality.

[0027] At the same time, the temperature stability cooperates with the stirring action of the circulation pump and the ultrasonic vibrator to promote the uniformity of the electroplating solution. The function of the circulation pump is to continuously circulate the electroplating solution, by sucking the electroplating solution from the bottom of the tank and then discharging it from the top of the tank, ensuring that the electroplating solution maintains a uniform flow throughout the tank. This circulation can not only maintain the uniform temperature distribution of the electroplating solution, but also reduce the phenomenon of temperature stratification in the electroplating tank, and further avoid the negative impact of local excessive or low temperatures on the electroplating effect. At the same time, the ultrasonic vibration generated by the ultrasonic vibrator during the electroplating process can help the electroplating solution flow more smoothly in the blind through hole, further promote the uniform distribution of temperature, and ensure that every part of the electroplating process can be within the ideal temperature range.

[0028] Through the synergistic effect of the temperature controller, insulation layer, circulation pump and ultrasonic vibrator, the present invention ensures that the temperature of the plating solution is maintained in a stable and uniform state throughout the electroplating process, which is crucial for improving the electroplating effect and ensuring the quality of the electroplating. The electroplating solution at a stable temperature can accelerate the ion exchange process, improve the quality of the coating, and avoid uneven plating or quality problems caused by temperature fluctuations; the combination of uniform stirring of the plating solution and stable temperature can also ensure the uniformity of the electroplating layer inside and outside the blind through hole, ensuring the efficiency and high quality of the entire electroplating process.

[0029] Furthermore, the present invention also introduces three key additives: C6H 12 Na2O6S4 (SPS accelerator), polyethylene glycol PEG-8000 (inhibitor) and Janus Green B (JGB, leveling agent) are used to optimize the electroplating process and significantly improve the uniformity and quality of the electroplating layer in blind through holes.

[0030] SPS(C6H 12 As an accelerator, SPS plays a major role in accelerating ion exchange during the electroplating process, promoting the reduction reaction of copper ions in the electroplating solution, thereby increasing the electroplating speed. During the electroplating process, SPS can reduce the electrochemical overpotential of the electroplating solution and reduce the deposition time of the coating. According to the following formula, the addition of SPS can increase the reduction rate of copper ions:

[0031] Cu 2+ +2e - →Cu(reduction reaction)

[0032] By accelerating the reduction reaction of copper ions, SPS effectively promotes the deposition of the coating, especially the deposition rate of the coating in the blind through hole is improved, avoiding the phenomenon of uneven or slow deposition of the coating in some blind through holes.

[0033] The main function of polyethylene glycol PEG-8000 (inhibitor) in the electroplating solution is to inhibit the rapid deposition of copper ions in the low overpotential area during the electroplating process. PEG-8000 forms a protective film by adsorbing on the surface of the electrode, reducing unnecessary copper deposition and ensuring the uniformity of the electroplating layer. This inhibitory effect can effectively reduce the "overpotential deposition" phenomenon that occurs during the electroplating process and prevent the copper ions in the electroplating solution from being deposited prematurely in inappropriate locations. The concentration of PEG-8000 has an important relationship with the uniformity of the electroplating layer, and its concentration is usually between 50mg / L and 300mg / L. Its mechanism of action can be expressed by the following formula:

[0034] Cu 2+ +2e - →Cu(deposition layer)

[0035] Due to the inhibitory effect of PEG-8000, the copper deposition rate is properly controlled during the electroplating process, especially in blind through holes. Due to the poor fluidity of the plating solution, PEG-8000 can ensure the uniformity of electroplating deposition and prevent local excessive deposition due to excessive current density.

[0036] As a leveling agent, JGB is mainly used to improve the surface quality of the electroplated layer and make the surface of the electroplated layer smoother and flatter. During the electroplating process, JGB can adjust the ion concentration in the electroplating solution, improve the crystal structure of the electroplated layer, and avoid problems such as uneven electroplating or rough surface. By adjusting the pH value and ion concentration of the electroplating solution, JGB promotes the uniform deposition of copper ions during the electroplating process and improves the finish of the coating. The concentration range of JGB is usually between 1mg / L and 40mg / L. Its role can be briefly described by the following chemical reaction:

[0037] Cu 2+ +2e - →Cu (uniform deposition layer)

[0038] JGB can effectively prevent uneven deposition, especially in the complex morphology of blind through holes, and can ensure uniform plating without pores, ensuring the quality and structural integrity of the electroplated layer in the hole.

[0039] The combined effect of these additives plays different roles at different stages, thus providing a more stable environment during the electroplating process, ensuring the ion exchange rate of the electroplating solution, the reduction reaction of copper ions, and the uniformity of the electroplated layer. Especially in the complex structure of blind through holes, SPS accelerates the electroplating process, PEG-8000 suppresses the overpotential deposition phenomenon, and JGB ensures the flatness and smoothness of the electroplated layer, so that the electroplated layer has better coverage and uniformity. Through the optimized use of these three additives, the present invention significantly improves the quality of the blind through hole electroplating layer, makes the electroplating process more efficient and stable, and the PCB board finally obtained has higher electrical performance and longer service life.

[0040] The beneficial effect of the present invention is that a movable ultrasonic vibrator is used to replace the traditional fixed position ultrasonic vibrator, and the ultrasonic emission position can be flexibly adjusted according to the specific position of the blind through hole. This innovative design effectively reduces the energy attenuation of the ultrasonic wave from the fixed position to the blind through hole, thereby avoiding the energy loss caused by the long distance in the traditional method, making the effect of the ultrasonic wave more concentrated, and achieving a better stirring effect. During the electroplating process, this ultrasonic vibrator with dynamic position adjustment can optimize the distribution of the plating solution in the blind through hole, improve the fluidity and uniformity of the plating solution, and solve the problem of uneven plating layer or poor deposition in the blind through hole in the traditional method. Through these technical improvements, the present invention not only performs outstandingly in improving the electroplating quality of blind through holes, but also has the characteristics of simple and convenient operation. During the electroplating process, the operator does not need to frequently adjust the electroplating equipment, but only needs to set the moving range and frequency of the ultrasonic vibrator to automatically adapt to different electroplating requirements. At the same time, the present invention significantly improves the overall production efficiency in the electroplating process of PCB blind through holes, reduces the production cycle and manual intervention, and optimizes the production process. By combining the temperature control of the electroplating solution, the efficient stirring of the ultrasonic vibrator, and the use of special additives, the present invention can ensure that the electroplating layer has excellent uniformity, smoothness and durability, thereby improving the quality and reliability of the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a PCB blind through hole electroplating method with an ultrasonic component in the present application;

[0042] Figure 2 is a top view of a PCB blind through hole electroplating method with an ultrasonic component of the present application;

[0043] Figure 3 This is a method flow chart of a PCB blind through hole electroplating method with an ultrasonic component in the present application.

[0044] Figure: ultrasonic vibrator fixture 1, ultrasonic vibrator 2, insulation layer 3, temperature controller 4, electroplating anode 5, circulation pump 6, electroplating tank 7, ultrasonic control module 8, temperature controller control module 9, power supply 10 DETAILED DESCRIPTION

[0045] The invention is further described below in conjunction with the accompanying drawings and embodiments, but the content of the invention is not limited to the scope of the embodiments.

[0046] Example 1

[0047] A method for electroplating a blind through hole of a PCB with an ultrasonic component comprises the following steps:

[0048] Obtain PCB with through-holes (aspect ratio 2:1) by mechanical drilling;

[0049] A thin copper layer with a thickness of 2 μm is deposited as a conductive layer by a chemical copper deposition process;

[0050] Start the power supply, put the PCB with a conductive layer into the electroplating tank, start the temperature controller, the temperature controller is connected to the power supply, the temperature controller heating device is located at the bottom of the electroplating tank, the temperature controller temperature collection device is located inside the electroplating tank, and the temperature is controlled at 20°C. At the same time, start the circulation pump, which is connected to the power supply, suck the plating solution in the electroplating tank from the outlet of the electroplating tank, and pump the plating solution into the electroplating tank from the inlet of the electroplating tank to form a cycle; the anode plate and the PCB are respectively connected to the anode and cathode of the power supply to maintain a current density of 2A / dm2; start the ultrasonic fixture device, which is connected to the power supply, adjust the ultrasonic vibrator to the first preset position, start the ultrasonic vibrator, emit ultrasonic waves, maintain the ultrasonic frequency of 28kHz, and connect the ultrasonic vibrator to the power supply for 2 hours of electroplating. After 0.5 hours of electroplating, the ultrasonic fixture moves with the ultrasonic vibrator to the second preset position and continues to emit ultrasonic waves. After another 0.5 hours, the ultrasonic vibrator returns to the first preset position, and the cycle is repeated until the end.

[0051] Example 2

[0052] A method for electroplating a blind through hole of a PCB with an ultrasonic component comprises the following steps:

[0053] PCB with blind vias (aspect ratio of 4:1) obtained by mechanical drilling;

[0054] A thin copper layer with a thickness of 1 μm is deposited as a conductive layer by a chemical copper deposition process;

[0055] Start the power supply, put the PCB with a conductive layer into the electroplating tank, start the temperature controller, the temperature controller is connected to the power supply, the temperature controller heating device is located at the bottom of the electroplating tank, the temperature controller temperature collection device is located inside the electroplating tank, and the temperature is controlled at 23°C. At the same time, start the circulation pump, which is connected to the power supply, suck the plating solution in the electroplating tank from the outlet of the electroplating tank, and pump the plating solution into the electroplating tank from the inlet of the electroplating tank to form a cycle; the anode plate and the PCB are respectively connected to the anode and cathode of the power supply to maintain a current density of 1.5A / dm2; start the ultrasonic fixture device, which is connected to the power supply, adjust the ultrasonic vibrator to the first preset position, start the ultrasonic vibrator, emit ultrasonic waves, maintain the ultrasonic frequency of 40kHz, and connect the ultrasonic vibrator to the power supply for 3 hours of electroplating. After 0.5 hours of electroplating, the ultrasonic fixture moves the ultrasonic vibrator to the second preset position with the ultrasonic vibrator, and continues to emit ultrasonic waves. After another 0.5 hours, the ultrasonic vibrator returns to the first preset position, and the cycle is repeated until the end.

[0056] Example 3

[0057] A method for electroplating a blind through hole of a PCB with an ultrasonic component comprises the following steps:

[0058] PCB with blind vias (aspect ratio of 10:1) obtained by mechanical drilling;

[0059] A thin copper layer with a thickness of 0.5 μm is deposited as a conductive layer by a chemical copper deposition process;

[0060] Start the power supply, put the PCB with a conductive layer into the electroplating tank, start the temperature controller, the temperature controller is connected to the power supply, the temperature controller heating device is located at the bottom of the electroplating tank, the temperature controller temperature collection device is located inside the electroplating tank, and the temperature is controlled at 25°C. At the same time, start the circulation pump, which is connected to the power supply, suck the plating solution in the electroplating tank from the outlet of the electroplating tank, and pump the plating solution into the electroplating tank from the inlet of the electroplating tank to form a cycle; the anode plate and the PCB are respectively connected to the anode and cathode of the power supply to maintain a current density of 0.7A / dm2; start the ultrasonic fixture device, which is connected to the power supply, adjust the ultrasonic vibrator to the first preset position, start the ultrasonic vibrator, emit ultrasonic waves, maintain the ultrasonic frequency of 80kHz, and connect the ultrasonic vibrator to the power supply for 4 hours of electroplating. After 0.5 hours of electroplating, the ultrasonic fixture moves the ultrasonic vibrator to the second preset position with the ultrasonic vibrator, and continues to emit ultrasonic waves. After another 0.5 hours, the ultrasonic vibrator returns to the first preset position, and the cycle is repeated until the end.

[0061] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification and drawings of the present invention are also included in the patent protection scope of the present invention.

Claims

1. A method for electroplating blind through holes of a PCB with an ultrasonic component, characterized in that: The following steps are involved: (1) Obtaining a PCB board with a blind through hole having an aspect ratio of 2:1 to 16:1; (2) Using chemical copper deposition process to deposit a conductive layer with a thickness of 0.2 to 3 μm on the PCB surface; (3) starting the power supply, placing the PCB with the conductive layer in the electroplating tank, starting the temperature controller, connecting the temperature controller control module to the power supply, setting the temperature controller heating device at the bottom of the electroplating tank, and the temperature acquisition device of the temperature controller inside the electroplating tank to control the temperature in the tank between 19 and 25° C.; starting the circulation pump, connecting the circulation pump to the power supply, sucking the plating solution from the outlet of the electroplating tank and pumping it in from the inlet to form a liquid circulation; (4) Connect the anode and cathode of the power supply to the anode plate and PCB board respectively, so that the electroplating process is maintained at 0.5~2A / dm 2 The current density is 2.14V. (5) starting the ultrasonic fixture device, which is connected to the ultrasonic control module, adjusting the ultrasonic vibrator to a first preset position, starting the ultrasonic vibrator to emit an ultrasonic frequency of 40 kHz, and connecting the ultrasonic vibrator to the ultrasonic control module and a power supply, and continuing the electroplating for 1 to 4 hours; (6) After 0.5 hours of electroplating, the ultrasonic fixture moves the ultrasonic vibrator to the second preset position and continues to emit ultrasonic waves. After another 0.5 hours, the ultrasonic vibrator returns to the first preset position, and this cycle is repeated until the electroplating is completed; This method achieves uniform distribution of the plating solution and improves the uniformity of the electroplating layer of the PCB blind through-hole by adjusting the position of the ultrasonic vibrator and the action of ultrasonic waves.

2. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The blind through hole is formed by mechanical drilling and laser drilling.

3. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The components of the electroplating solution include CuSO4·5H2O, with a concentration range of 60g to 220g / L; H2SO4, with a concentration range of 80g to 260g / L; HCl, with a concentration range of 50mg to 80mg / L; C6H 12 Na2O6S4 (SPS), the concentration range is 0.5-10 mg / L; polyethylene glycol (PEG-8000), the concentration range is 50-300 mg / L; Janus Green B (JGB), the concentration range is 1-40 mg / L.

4. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The plating solution is stirred by ultrasonic waves and a circulation pump. The circulation pump sucks the plating solution from the outlet at the bottom of the long side of the plating tank and pumps the plating solution back to the plating tank from the inlet at the narrow side to form a closed circulation system, further improving the fluidity of the plating solution.

5. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The ultrasonic vibrator is fixed by a vibrator clamp and moves up and down and forward and backward under the drive of the ultrasonic controller. It moves once every half an hour. The ultrasonic vibrator emits ultrasonic waves with a frequency of 25 to 120 kHz. The position movement and frequency are controlled by the same ultrasonic control module. When electroplating starts, the ultrasonic vibrator clamp and the ultrasonic vibrator are located at a first preset position. After half an hour of electroplating, it moves to a second preset position, and returns to the first preset position after another half an hour, and repeats this cycle.

6. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The temperature collection device of the temperature controller collects the temperature in the electroplating tank in real time, and heats the electroplating tank to a predetermined temperature through the heating plate. The insulation layer is used to maintain the stability of the temperature in the electroplating tank. The heating and temperature collection functions of the temperature controller are managed by the temperature controller control module.

7. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The current density during the electroplating process is dynamically adjustable. A lower current density is used at the beginning of electroplating to enhance the initial deposition stability of the conductive layer, and then the current density is gradually increased to speed up the electroplating speed.

8. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: The vibration amplitude of the ultrasonic vibrator is adjustable to meet the electroplating requirements of blind through holes with different aspect ratios. The fluidity and deposition effect of the electroplating solution are further optimized by adjusting the vibration amplitude.

9. A PCB blind through hole electroplating method with an ultrasonic component according to claim 1, characterized in that: Auxiliary additives are added to the electroplating solution to improve the density and bonding strength of the electroplating layer inside the blind through hole, thereby improving the filling quality of the blind through hole.

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