Ultra-thin transformer line orifice copper plating process
By adopting drilling, internal shrinkage and copper plating processes in the production process of ultra-thin transformers, the problem of thickness of the orifice position of flexible circuit boards is solved, and the orifice flatness and the performance of ultra-thin transformers are improved.
Patent Information
- Application Number
- CN202510107001.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2025-04-11
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
During the production process of ultra-thin transformers, the thickness of the flexible circuit board orifice position leads to super-thickness of the total inductor thickness and uneven stacking, affecting the performance and quality of the ultra-thin transformer.
A copper plating process for ultra-thin transformer line orifices is adopted, including drilling, internal shrinkage and copper plating. By reducing the vacuum adsorption pressure during the drilling process, reducing the orifice deformation, and then performing copper foil shrinkage treatment to ensure the uniformity of the orifice copper thickness, and finally copper plating operation is carried out.
The flatness of the ultra-thin transformer line orifices is improved, and the overall thickness of the inductor and uneven layering caused by abnormal orifice thickness are solved, the performance and quality stability of the ultra-thin transformer is improved, the defect rate is reduced and the product pass rate is improved.
Smart Images
Figure CN119815701A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of copper plating at an ultra-thin transformer hole, in particular to a copper plating process for an ultra-thin transformer circuit hole. Background Art
[0002] Ultra-thin transformers are transformers with thinner structural design. With their unique advantages, ultra-thin transformers play an important role in many fields with high requirements for space and performance. With the continuous advancement of material science and manufacturing technology, their performance and application scope are still expanding.
[0003] In the production process of ultra-thin transformers, the thickness of the flexible circuit board at the orifice position is a key problem that needs to be solved urgently. Since the ultra-thin transformer needs to realize the voltage-boosting and voltage-reducing transformation functions, a large current requirement is imposed on the current passing through the copper foil. Therefore, the copper thickness of the flexible circuit board usually needs to reach more than 60um (the normal thickness is about 8um). However, there are high and low current differences and orifice tip discharge effects during the electroplating process, which make the copper thickness at the orifice position grow faster under the electroplating conditions of the same process. Moreover, even if the current distribution is evened out by a small current, the thickness difference can be reduced, but it still cannot meet the inductor thickness and flatness requirements, which leads to the phenomenon of excessive total inductor thickness and uneven stacking, affecting the performance and quality of the ultra-thin transformer. Therefore, it is necessary to invent a process for copper plating at the orifice of an ultra-thin transformer circuit to solve the above problems. Summary of the invention
[0004] The present invention provides the following technical solution: a process for copper plating of an ultra-thin transformer circuit opening, comprising the following steps: S1. Drilling First, fix the flexible circuit board to be drilled on the workbench of the high-precision CNC drilling machine to ensure that the circuit board is installed flat and accurately in position. Select a suitable carbide drill bit according to the material and thickness of the circuit board and install it on the spindle of the drilling machine. Accurately adjust the height of the drill bit to make it perpendicular to the surface of the circuit board with a deviation of no more than ±0.02mm. Enter the preset drilling parameters in the drilling machine control system, turn on the vacuum adsorption system, and initially set the adsorption pressure to 0.5MPa. Start the drilling machine for drilling operation. During the drilling process, observe the orifice deformation in real time through the online monitoring system. After a certain number of holes are drilled, stop the drilling machine and use three The dimensional profiler measures the orifice deformation. According to the measurement results, if the deformation does not reach the minimum value, the vacuum adsorption pressure is gradually reduced, such as to 0.45MPa, and drilling and measurement are performed again. This process is repeated until the optimal vacuum adsorption pressure is found. After determining the optimal vacuum adsorption pressure, the micro-lubrication cooling system is turned on, and then the drilling operation is continued until all holes are processed. After the drilling is completed, the circuit board is cleaned to remove the residual cutting fluid and drilling waste on the surface, and then the orifice quality is comprehensively inspected, including the hole position accuracy, diameter accuracy, orifice flatness and hole wall roughness, to ensure that the drilling quality meets the ultra-thin transformer manufacturing requirements.
[0005] S2, indentation processing Place the drilled flexible circuit board into an ultrasonic cleaning machine, add an appropriate amount of special electronic cleaning agent, start the cleaning machine, and use the cavitation effect of ultrasound to remove debris and impurities on the hole and copper foil surface. After cleaning, take out the circuit board and blow dry the residual cleaning liquid on the surface with clean compressed air. According to the thickness of the copper foil of the circuit board and the process requirements, prepare an etchant with a concentration of 15%, add the etchant to the corrosion-resistant treatment tank, install and debug the high-precision spray device, ensure that the nozzle is not blocked, and the initial spray pressure is set to 0.2MPa. Place the cleaned circuit board horizontally in the treatment tank, start the spray device, and spray the etchant evenly on the surface of the hole copper foil. The spray time is set to 2 minutes. During the etching process In the process, the shrinkage of the copper foil edge of the hole is observed in real time through an online microscope, and the temperature of the etchant is stabilized at 35°C using a temperature control system. When the copper foil at the hole is observed to shrink to a size close to the predetermined size, the spraying is stopped. After the etching is completed, the circuit board is quickly transferred to the neutralization tank, and an alkaline neutralizer with a concentration of 8% is poured in for 1.5 minutes. After the neutralization is completed, the circuit board is passed through a multi-stage countercurrent cleaning tank in turn, first rinsed with deionized water at a flow rate of 5L / min for 30 seconds, and then in the high-pressure spray area, it is sprayed and cleaned with 0.3MPa high-pressure deionized water for 1 minute, and the circuit board is placed in a 55°C hot air drying device for 3-5 minutes to ensure that the surface of the circuit board is completely dry.
[0006] S3, copper plating Put the flexible circuit board to be copper-plated into an alkaline degreasing tank, adjust the degreasing agent concentration to 8%, and add an appropriate amount of surfactant. Heat the tank temperature to 45°C, soak the circuit board for 4 minutes, take it out, rinse it with clean water, then put the circuit board into sodium persulfate micro-etching solution, the sodium persulfate concentration in the micro-etching solution is 65g / L, and the pH value is adjusted to 3 with sulfuric acid. Treat it at room temperature for 1.5 minutes to make the micro-etching depth reach about 1um, then rinse it with clean water, and finally put the circuit board into the pre-dip tank. The composition of the pre-dip solution is the same as that of the copper plating solution but does not contain copper ions. After soaking at room temperature for 45 seconds, copper plating is immediately performed. Put the pretreated circuit board into the copper plating tank, connect the pulse electroplating power supply, control the temperature of the copper plating solution at 25°C, and keep the circulation filtration system in normal operation. The filtration accuracy is 8μm, the copper sulfate content in the copper plating solution is 200g / L, the sulfuric acid is 60g / L, the chloride ion is 50ppm, and the copper plating time is set to 90 minutes. During the copper plating process, an X-ray fluorescence thickness gauge is used to measure the coating thickness every 15 minutes, and the growth of the coating at the hole mouth is observed through a microscope to ensure uniform growth of the coating. After the copper plating is completed, the circuit board is quickly transferred to the water washing tank, first rinsed with tap water at a flow rate of 5L / min for 1.5 minutes, and then immersed in deionized water for 2.5 minutes, the circuit board is taken out and placed in a passivation tank, and finally dried. Hot air drying is used to ensure that the circuit board is thoroughly dried without moisture residue, completing the entire copper plating process to obtain a high-quality copper-plated circuit board that meets the requirements of ultra-thin transformers.
[0007] Preferably, in step S1, the drilling speed is 8000-12000 r / min, the feed speed is 50-100 mm / s, the cooling and lubrication system is turned on 0.1-0.2 s before the drill bit enters the circuit board, and the spraying is stopped 0.2-0.3 s after the drill bit exits the circuit board, and the flow rate is controlled at 5-10 ml / min.
[0008] Preferably, in step S2, the ultrasonic cleaning machine is set to have a cleaning time of 4 minutes and a temperature of 45°C.
[0009] Preferably, in step S3, the forward pulse current density is set to 4ASD, the reverse pulse current density is set to 0.8ASD, the pulse frequency is set to 800Hz, and the duty cycle is set to 20%.
[0010] (II) Beneficial effects Compared with the prior art, the present invention provides a process for copper plating of an ultra-thin transformer circuit opening, which has the following beneficial effects: 1. The copper plating process for the hole of the ultra-thin transformer circuit is to drill holes on the surface of the copper foil of the flexible circuit board, and at the same time reduce the vacuum adsorption pressure, so as to minimize the hole deformation caused by vacuum absorption after drilling, and to increase the copper foil shrinkage process for the copper foil at the hole, so as to avoid the copper foil at the hole after copper plating. Increase the copper thickness abnormally.
[0011] 2. The copper plating process for the circuit holes of ultra-thin transformers improves the flatness of the circuit holes of ultra-thin transformers, solves the problems of excessive total thickness of the inductor and uneven stacking caused by abnormal hole thickness, and improves the performance and quality stability of ultra-thin transformers. After testing and sample stage verification, the defective rate was reduced from the original 100% to 0%, which improved the product qualification rate, reduced production costs, and improved production efficiency. It also provides a new and effective process solution, which provides strong technical support for the company in the competition in the ultra-thin transformer market, helps the company to expand the market, increase market share, and promote the further development of ultra-thin transformer technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a schematic diagram of the drilling state structure of the present invention; Figure 2 This is a schematic diagram of the abnormal structure of the tip discharge of the present invention; Figure 3 It is a schematic diagram of the structure of the shrinkage processing state of the present invention. DETAILED DESCRIPTION
[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0014] See also Figure 1-3 The present invention provides a technical solution: a process for copper plating of an ultra-thin transformer circuit opening, comprising the following steps: S1. Drilling First, fix the flexible circuit board to be drilled on the workbench of the high-precision CNC drilling machine to ensure that the circuit board is installed flat and accurately in position. Select a suitable carbide drill bit according to the material and thickness of the circuit board and install it on the spindle of the drilling machine. Accurately adjust the height of the drill bit so that it is perpendicular to the surface of the circuit board with a deviation of no more than ±0.02mm. Enter the preset drilling parameters in the drilling machine control system. The drilling speed is 8000-12000r / min, the feed speed is 50-100mm / s, the cooling and lubrication system is turned on 0.1-0.2s before the drill bit enters the circuit board, and the spraying is stopped 0.2-0.3s after the drill bit exits the circuit board. The flow rate is controlled at 5-10ml / min, and the vacuum adsorption system is turned on. The initial adsorption pressure is set to 0.5MPa, and the drilling machine is started. Drilling operation: During the drilling process, the orifice deformation is observed in real time through the online monitoring system. After a certain number of holes are drilled, the drilling machine is stopped and the orifice deformation is measured using a three-dimensional profiler. According to the measurement results, if the deformation has not reached the minimum value, the vacuum adsorption pressure is gradually reduced, such as to 0.45MPa, and drilling and measurement are performed again. This process is repeated until the optimal vacuum adsorption pressure is found. After determining the optimal vacuum adsorption pressure, the micro-lubrication cooling system is turned on, and then the drilling operation is continued until all holes are processed. After drilling is completed, the circuit board is cleaned to remove the residual cutting fluid and drilling waste on the surface, and then the orifice quality is comprehensively inspected, including the hole position accuracy, diameter accuracy, orifice flatness and hole wall roughness, to ensure that the drilling quality meets the ultra-thin transformer manufacturing requirements.
[0015] S2, indentation processing Place the drilled flexible circuit board into an ultrasonic cleaning machine, add an appropriate amount of special electronic cleaning agent, set the cleaning time of the ultrasonic cleaning machine to 4 minutes and the temperature to 45°C, start the cleaning machine, and use the cavitation effect of ultrasound to remove debris and impurities on the hole and copper foil surface. After cleaning, take out the circuit board and blow dry the residual cleaning liquid on the surface with clean compressed air. According to the thickness of the copper foil of the circuit board and the process requirements, prepare an etchant with a concentration of 15%, add the etchant to the corrosion-resistant treatment tank, install and debug the high-precision spray device to ensure that the nozzle is not blocked, and the initial spray pressure is set to 0.2MPa. Place the cleaned circuit board horizontally in the treatment tank, start the spray device, and spray the etchant evenly on the surface of the hole copper foil. The spray time Set to 2 minutes. During the etching process, the shrinkage of the edge of the copper foil at the hole is observed in real time through an online microscope. At the same time, the temperature of the etchant is stabilized at 35°C using a temperature control system. When the copper foil at the hole is observed to shrink to a size close to the predetermined size, the spraying is ready to be stopped. After the etching is completed, the circuit board is quickly transferred to the neutralization tank, and an alkaline neutralizer with a concentration of 8% is poured in. The neutralization time is 1.5 minutes. After the neutralization is completed, the circuit board is passed through a multi-stage countercurrent cleaning tank in turn. First, it is initially rinsed with deionized water at a flow rate of 5L / min for 30 seconds, and then in the high-pressure spray area, it is sprayed and cleaned with 0.3MPa high-pressure deionized water for 1 minute. The circuit board is placed in a 55°C hot air drying device for 3-5 minutes to ensure that the surface of the circuit board is completely dry.
[0016] S3, copper plating Place the flexible circuit board to be copper-plated in an alkaline degreasing tank with a degreasing agent concentration of 8%, add an appropriate amount of surfactant, heat the tank temperature to 45°C, soak the circuit board for 4 minutes, take it out, rinse it with clean water, then place the circuit board in a sodium persulfate micro-etching solution with a sodium persulfate concentration of 65g / L, adjust the pH value to 3 with sulfuric acid, treat it at room temperature for 1.5 minutes, so that the micro-etching depth reaches about 1um, then rinse it with clean water, finally place the circuit board in a pre-dip tank with the same composition as the copper plating solution but without copper ions. After soaking at room temperature for 45 seconds, immediately perform copper plating, place the pre-treated circuit board in a copper plating tank, connect the pulse electroplating power supply, set the forward pulse current density to 4ASD, the reverse pulse current density to 0.8ASD, the pulse frequency to 800Hz, and the duty cycle to 20%. The temperature of the copper plating solution is controlled at 25°C, the circulating filtration system maintains normal operation, the filtration accuracy is 8μm, the copper sulfate content in the copper plating solution is 200g / L, the sulfuric acid is 60g / L, the chloride ion is 50ppm, and the copper plating time is set to 90 minutes. During the copper plating process, an X-ray fluorescence thickness gauge is used to measure the coating thickness every 15 minutes, and the growth of the orifice coating is observed through a microscope to ensure uniform growth of the coating. After the copper plating is completed, the circuit board is quickly transferred to a water washing tank, first rinsed with tap water at a flow rate of 5L / min for 1.5 minutes, and then immersed in deionized water for 2.5 minutes, the circuit board is taken out and placed in a passivation tank, and finally dried. Hot air drying is used to ensure that the circuit board is thoroughly dried without moisture residue, completing the entire copper plating process to obtain a high-quality copper-plated circuit board that meets the requirements of ultra-thin transformers.
[0017] The copper plating process for the hole of the ultra-thin transformer circuit drills holes on the surface of the copper foil of the flexible circuit board and reduces the vacuum adsorption pressure at the same time, thereby minimizing the hole deformation caused by vacuum absorption after drilling, and adding a copper foil shrinkage process to the copper foil at the hole. The copper foil at the hole is shrunk to avoid the abnormal increase in copper thickness after copper plating, thereby improving the flatness of the hole of the ultra-thin transformer circuit, solving the problems of excessive total inductance thickness and uneven stacking caused by abnormal hole thickness, and improving the performance and quality stability of the ultra-thin transformer. After testing and sample stage verification, the defective rate was reduced from the original 100% to 0%, which increased the product qualification rate, reduced production costs, and improved production efficiency. It also provides a new and effective process solution, which provides strong technical support for the company in the competition in the ultra-thin transformer market, helps the company to expand the market, increase market share, and promote the further development of ultra-thin transformer technology.
[0018] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A process for copper plating of an ultra-thin transformer circuit opening, characterized in that: The following steps are involved: S1. Drilling First, fix the flexible circuit board to be drilled on the workbench of the high-precision CNC drilling machine to ensure that the circuit board is installed flat and accurately in position. Select a suitable carbide drill bit according to the material and thickness of the circuit board and install it on the spindle of the drilling machine. Accurately adjust the height of the drill bit to make it perpendicular to the surface of the circuit board with a deviation of no more than ±0.02mm. Enter the preset drilling parameters in the drilling machine control system, turn on the vacuum adsorption system, and initially set the adsorption pressure to 0.5MPa. Start the drilling machine for drilling operation. During the drilling process, observe the orifice deformation in real time through the online monitoring system. After a certain number of holes are drilled, stop the drilling machine and use three The dimensional profiler measures the orifice deformation. According to the measurement results, if the deformation does not reach the minimum value, the vacuum adsorption pressure is gradually reduced, such as to 0.45MPa, and drilling and measurement are performed again. This process is repeated until the optimal vacuum adsorption pressure is found. After the optimal vacuum adsorption pressure is determined, the micro-lubrication cooling system is turned on, and then the drilling operation is continued until all holes are processed. After the drilling is completed, the circuit board is cleaned to remove the residual cutting fluid and drilling waste on the surface, and then the orifice quality is fully tested, including the hole position accuracy, diameter accuracy, orifice flatness and hole wall roughness, to ensure that the drilling quality meets the ultra-thin transformer manufacturing requirements; S2, indentation processing Place the drilled flexible circuit board into an ultrasonic cleaning machine, add an appropriate amount of special electronic cleaning agent, start the cleaning machine, and use the cavitation effect of ultrasound to remove debris and impurities on the hole and copper foil surface. After cleaning, take out the circuit board and blow dry the residual cleaning liquid on the surface with clean compressed air. According to the thickness of the copper foil of the circuit board and the process requirements, prepare an etchant with a concentration of 15%, add the etchant to the corrosion-resistant treatment tank, install and debug the high-precision spray device, ensure that the nozzle is not blocked, and the initial spray pressure is set to 0.2MPa. Place the cleaned circuit board horizontally in the treatment tank, start the spray device, and spray the etchant evenly on the surface of the hole copper foil. The spray time is set to 2 minutes. During the etching process In the process, the shrinkage of the copper foil edge of the orifice is observed in real time through an online microscope, and the temperature of the etchant is stabilized at 35°C by a temperature control system. When the copper foil at the orifice is observed to shrink to a predetermined size, the spraying is ready to be stopped. After the etching is completed, the circuit board is quickly transferred to the neutralization tank, and an alkaline neutralizer with a concentration of 8% is poured in. The neutralization time is 1.5 minutes. After the neutralization is completed, the circuit board is sequentially passed through a multi-stage countercurrent cleaning tank, first rinsed with deionized water at a flow rate of 5L / min for 30 seconds, and then in the high-pressure spray area, it is sprayed and cleaned with 0.3MPa high-pressure deionized water for 1 minute, and the circuit board is placed in a 55°C hot air drying device for 3-5 minutes to ensure that the surface of the circuit board is completely dry; S3, copper plating Put the flexible circuit board to be copper-plated into an alkaline degreasing tank, adjust the degreasing agent concentration to 8%, and add an appropriate amount of surfactant. Heat the tank temperature to 45°C, soak the circuit board for 4 minutes, take it out, rinse it with clean water, then put the circuit board into sodium persulfate micro-etching solution, the sodium persulfate concentration in the micro-etching solution is 65g / L, and the pH value is adjusted to 3 with sulfuric acid. Treat it at room temperature for 1.5 minutes to make the micro-etching depth reach about 1um, then rinse it with clean water, and finally put the circuit board into the pre-dip tank. The composition of the pre-dip solution is the same as that of the copper plating solution but does not contain copper ions. After soaking at room temperature for 45 seconds, copper plating is immediately performed. Put the pretreated circuit board into the copper plating tank, connect the pulse electroplating power supply, control the temperature of the copper plating solution at 25°C, and keep the circulation filtration system in normal operation. The filtration accuracy is 8μm, the copper sulfate content in the copper plating solution is 200g / L, the sulfuric acid is 60g / L, the chloride ion is 50ppm, and the copper plating time is set to 90 minutes. During the copper plating process, an X-ray fluorescence thickness gauge is used to measure the coating thickness every 15 minutes, and the growth of the coating at the hole mouth is observed through a microscope to ensure uniform growth of the coating. After the copper plating is completed, the circuit board is quickly transferred to the water washing tank, first rinsed with tap water at a flow rate of 5L / min for 1.5 minutes, and then immersed in deionized water for 2.5 minutes, the circuit board is taken out and placed in a passivation tank, and finally dried. Hot air drying is used to ensure that the circuit board is thoroughly dried without moisture residue, completing the entire copper plating process to obtain a high-quality copper-plated circuit board that meets the requirements of ultra-thin transformers.
2. The process for copper plating of an ultra-thin transformer circuit opening according to claim 1, characterized in that: In step S1, the drilling speed is 8000-12000 r / min, the feed speed is 50-100 mm / s, the cooling and lubrication system is turned on 0.1-0.2 s before the drill enters the circuit board, and the spraying is stopped 0.2-0.3 s after the drill exits the circuit board, and the flow rate is controlled at 5-10 ml / min.
3. The process for copper plating of an ultra-thin transformer circuit opening according to claim 1, characterized in that: In step S2, the ultrasonic cleaning machine is set to clean for 4 minutes at a temperature of 45°C.
4. The process for copper plating of an ultra-thin transformer circuit opening according to claim 1, characterized in that: In step S3, the forward pulse current density is set to 4ASD, the reverse pulse current density is set to 0.8ASD, the pulse frequency is set to 800Hz, and the duty cycle is set to 20%.