Step copper process for PCB (Printed Circuit Board)

Abstract

The invention relates to the technical field of PCB step copper, in particular to a PCB step copper process. The raw materials are cut into plates with required sizes, and conventional oil removal and oxide layer removal pretreatment is carried out; a layer of thin copper is formed on the plate surface through a copper deposition process and serves as the basis of subsequent electroplating, and a flash plating process is carried out by using 8ASF low current; and the polishing brush is closed, the copper surface is cleaned and coarsened through a chemical micro-etching process, the adhesive force of the dry film and the copper surface is enhanced, and the dry film is accurately pressed and coated on the plate surface through a 105 DEG C film pressing process. According to the method, the secondary circuit process is adopted, the first-order copper is protected from being electroplated through the first-order circuit dry film, production of first-order copper, second-order copper and even more-order copper is achieved, the complex process and the production cost are reduced, meanwhile, high-precision circuit pattern manufacturing is achieved through the LDI technology, and the precision and consistency of the circuit are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of stepped copper for PCB boards, and specifically to a stepped copper process for PCB boards. Background Art

[0002] With the development of electronic products towards miniaturization and multi-functionality, the design of PCB boards has become increasingly complex.

[0003] However, generally, in some specific PCB board applications, such as different layers of a multi-layer board need to carry different currents, or to meet specific signal requirements, it is often necessary to achieve copper foil distributions of different thicknesses on the same PCB board, that is, a stepped copper structure. Traditional PCB board manufacturing processes have some defects in achieving stepped copper, such as complex processes, high costs, and difficulty in controlling accuracy.

[0004] Based on this, the present invention provides a stepped copper process for PCB boards to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a stepped copper process for PCB boards to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A stepped copper process for PCB boards includes the following steps:

[0008] S1. Cut the raw materials into sheet materials of the required size, and perform conventional degreasing and deoxidation layer pretreatment to ensure the cleanliness of the board surface;

[0009] S2. Through the copper deposition process, form a thin layer of copper on the board surface as the basis for subsequent electroplating. Use a low current of 8 ASF for flash plating to ensure complete conduction of the hole copper and surface copper, and maintain good surface copper uniformity. In this step, optimize the electroplating solution formula to improve the bonding force between the copper layer and the substrate;

[0010] S3. Turn off the brush, and use the chemical micro-etching process to clean and roughen the copper surface to enhance the adhesion of the dry film to the copper surface. Use a 105 °C film pressing process to accurately press the dry film on the board surface to ensure no bubbles and no wrinkles;

[0011] S4. Through the LDI direct imaging process, perform a polymerization reaction on the dry film on the board surface to form an accurate circuit pattern. Use a 1.0% sodium carbonate solution to remove the unreacted dry film, and retain the polymerized reaction pattern, that is, the first stepped copper area is protected by the dry film;

[0012] S5. Since the first-stage copper is protected by the dry film, the electroplating process only electroplates the copper on the area not protected by the dry film. Set the electroplating parameters according to the actual copper thickness requirements to ensure that the second-stage copper reaches the predetermined thickness. At the same time, introduce an intelligent electroplating control system to monitor the electroplating solution concentration and electroplating speed in real time, and improve the electroplating accuracy;

[0013] S6. Use the chemical micro-etching process to clean and roughen the copper surface again. Use a 105°C film laminating process to press a new dry film onto the board surface, and form a secondary circuit pattern through the LDI direct imaging process. The exposure data here needs to be designed for pattern compensation according to the stepped copper thickness;

[0014] S7. Develop using a 1.0% sodium carbonate process, and then remove the unprotected copper layer through the chemical copper etching process to form a secondary circuit. Remove all the dry film on the surface to expose the final stepped copper structure;

[0015] S8. Perform the conventional treatment of outer layer solder mask and silk screen printing. Use an automatic optical inspection device to comprehensively inspect the PCB board to ensure that the circuit and stepped copper structure are correct;

[0016] S9. Vacuum package the qualified PCB boards to prevent moisture absorption or damage during transportation and storage.

[0017] Preferably, the implementation steps of step S1 are as follows:

[0018] S1.1. Use professional cutting equipment to cut the copper clad laminate into sheet materials of the required size according to the design specifications;

[0019] S1.2. Put the cut sheet materials into the degreasing tank, and use an alkaline degreaser to remove the grease and dirt on the board surface and in the holes;

[0020] S1.3. Use an acidic solution to remove the oxide layer on the board surface and remove the oxide film on the copper surface;

[0021] S1.4. Use an ultrasonic cleaning device to thoroughly clean the board surface to ensure no impurities and no dust.

[0022] Preferably, the implementation steps of step S2 are as follows:

[0023] S2.1. Put the clean and dry sheet materials into the copper deposition tank, and deposit copper ions on the board surface chemically to form a thin copper layer;

[0024] S2.2. Prepare an 8 ASF low-current electroplating solution to ensure that the electroplating solution components are uniform and the temperature is appropriate;

[0025] S2.3. Turn on the power supply and perform flash plating at a low current to ensure thorough conduction of the hole copper and surface copper;

[0026] S2.4. Adjust the additives and concentration in the electroplating solution according to actual production experience to improve the adhesion between the copper layer and the substrate.

[0027] Preferably, the implementation steps of step S3 are as follows:

[0028] S3.1. Use a chemical micro-etchant to clean and roughen the copper surface to enhance the adhesion between the dry film and the copper surface;

[0029] S3.2. Select a suitable type and specification of dry film;

[0030] S3.3. Use a 105°C film laminating process to accurately laminate the dry film on the board surface, ensuring no bubbles and no wrinkles;

[0031] S3.4. Inspect the laminated dry film to ensure no damage and no displacement.

[0032] Preferably, the implementation steps of step S4 are as follows:

[0033] S4.1. Use an LDI device to carry out a polymerization reaction on the dry film on the board surface to form an accurate circuit pattern;

[0034] S4.2. Use a 1.0% sodium carbonate solution to develop the exposed dry film to remove the unreacted dry film;

[0035] S4.3. Inspect the developed dry film to ensure the circuit pattern is complete and without damage.

[0036] Preferably, the implementation steps of step S5 are as follows:

[0037] S5.1. Set the electroplating parameters, current density and electroplating time according to the actual copper thickness requirement;

[0038] S5.2. Place the board material with the first-step copper protected into the electroplating tank and carry out the copper electroplating process with the set electroplating parameters;

[0039] S5.3. After electroplating is completed, take out the board material and rinse it with clean water to remove the residual electroplating solution.

[0040] Preferably, the implementation steps of step S6 are as follows:

[0041] S6.1. Use the chemical micro-etchant again to clean and roughen the copper surface to prepare for the second dry film lamination;

[0042] S6.2. Use a 105°C film laminating process to laminate a new dry film on the board surface, ensuring no bubbles and no wrinkles;

[0043] S6.3. Carry out a polymerization reaction on the second dry film through an LDI device to form a second circuit pattern.

[0044] Preferably, the implementation steps of step S7 are as follows:

[0045] S7.1. Develop the dry film after secondary exposure using a 1.0% sodium carbonate process to remove the unreacted dry film.

[0046] S7.2. Etch the unprotected copper layer using a chemical etchant to form the secondary circuit.

[0047] S7.3. Remove all the dry film on the surface to expose the final stepped copper structure.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] The present invention adopts a secondary circuit process. The dry film of the first circuit protects the first-order copper from being electroplated, enabling the production of second-order copper and even more-order copper, reducing complex processes and production costs. At the same time, through LDI technology, high-precision circuit pattern production is achieved, ensuring the accuracy and consistency of the circuits.

[0050] The present invention introduces an intelligent electroplating control system during the electroplating process to monitor the concentration of the electroplating solution and the electroplating speed in real time, greatly improving the accuracy and stability of electroplating. The process flow is reasonably designed, the steps are compact, reducing unnecessary waiting time and operations, and improving production efficiency. Processes such as chemical micro-etching and dry film lamination are used to enhance the adhesion between the dry film and the copper surface, reducing quality problems in subsequent processing. The dry film, electroplating solution, and etchant used in the process have wide adaptability and compatibility, suitable for the production of PCB boards with different specifications and requirements. By adjusting parameters such as current density, electroplating time, and etching temperature, the thickness of the copper layer and the width of the circuit can be flexibly controlled to meet different design requirements. At the same time, the present invention also ensures the quality and reliability of the PCB board through strict pretreatment, copper deposition, flash plating, electroplating, etching and other steps, uses automatic optical inspection equipment to comprehensively inspect the PCB board, promptly discovers and corrects potential problems, and improves the qualified rate of the finished product. Description of the Drawings

[0051] Figure 1 It is a process flow chart of the stepped copper process for the PCB board of the present invention. Detailed Embodiments

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0053] Embodiment 1

[0054] Please refer to Figure 1 , the present invention provides a stepped copper process for a PCB board, comprising the following steps:

[0055] S1. Cut the raw materials into sheet materials of required sizes, and perform conventional degreasing and deoxidation layer pretreatment to ensure the cleanliness of the board surface;

[0056] S2. Through the electroless copper plating process, form a thin copper layer on the board surface as the basis for subsequent electroplating. Use a low current of 8 ASF for flash plating to ensure complete conduction of the hole copper and surface copper, and maintain good surface copper uniformity. In this step, optimize the electroplating solution formula to improve the adhesion between the copper layer and the substrate;

[0057] S3. Turn off the brush, and use the chemical micro-etching process to clean and roughen the copper surface to enhance the adhesion between the dry film and the copper surface. Use a 105°C film laminating process to precisely laminate the dry film on the board surface to ensure no bubbles and no wrinkles;

[0058] S4. Through the LDI direct imaging process, perform a polymerization reaction on the dry film on the board surface to form a precise circuit pattern. Use a 1.0% sodium carbonate solution to remove the unreacted dry film, and retain the polymerized pattern, that is, the first stepped copper area is protected by the dry film;

[0059] S5. Since the first stepped copper is protected by the dry film, this electroplating process only electroplates the copper on the area not protected by the dry film. Set the electroplating parameters according to the actual copper thickness requirements to ensure that the second stepped copper reaches the predetermined thickness. At the same time, introduce an intelligent electroplating control system to monitor the electroplating solution concentration and electroplating speed in real time to improve the electroplating accuracy;

[0060] S6. Use the chemical micro-etching process again to clean and roughen the copper surface, use a 105°C film laminating process to laminate a new dry film on the board surface, and form a secondary circuit pattern through the LDI direct imaging process. Here, the exposure data needs to be designed with graphic compensation according to the stepped copper thickness;

[0061] S7. Develop using a 1.0% sodium carbonate process, and then remove the unprotected copper layer through the chemical copper etching process to form a secondary circuit, and remove all the dry film on the surface to expose the final stepped copper structure;

[0062] S8. Perform conventional outer layer solder mask and silk screen processing, and use an automatic optical inspection device to comprehensively inspect the PCB board to ensure that the circuit and stepped copper structure are correct;

[0063] S9. Vacuum package the qualified PCB board to prevent moisture absorption or damage during transportation and storage.

[0064] In this embodiment, it should also be noted that the implementation steps of step S1 are:

[0065] S1.1. Use professional cutting equipment to cut the copper clad laminate into sheets of the required size according to the design specifications;

[0066] S1.2. Place the cut sheets into a degreasing tank and use an alkaline degreaser to remove the grease and dirt on the board surface and in the holes;

[0067] S1.3. Use an acidic solution to remove the oxide layer on the board surface and remove the oxide film on the copper surface;

[0068] S1.4. Use ultrasonic cleaning equipment to thoroughly clean the board surface to ensure no impurities and no dust.

[0069] In this embodiment, it should also be noted that the implementation steps of step S2 are as follows:

[0070] S2.1. Place the clean and dry sheets into a copper deposition tank and chemically deposit copper ions on the board surface to form a thin copper layer;

[0071] S2.2. Prepare an 8 ASF low-current electroplating solution to ensure uniform composition and appropriate temperature of the electroplating solution;

[0072] S2.3. Turn on the power supply and perform flash plating at a low current to thoroughly conduct the hole copper and surface copper;

[0073] S2.4. According to actual production experience, adjust the additives and concentration in the electroplating solution to improve the adhesion between the copper layer and the substrate.

[0074] In this embodiment, it should also be noted that the implementation steps of step S3 are as follows:

[0075] S3.1. Use a chemical micro-etchant to clean and roughen the copper surface to enhance the adhesion of the dry film to the copper surface;

[0076] S3.2. Select a suitable type and specification of dry film;

[0077] S3.3. Use a 105 °C film laminating process to precisely laminate the dry film on the board surface to ensure no bubbles and no wrinkles;

[0078] S3.4. Inspect the laminated dry film to ensure no damage and no displacement.

[0079] In this embodiment, it should also be noted that the implementation steps of step S4 are as follows:

[0080] S4.1. Use an LDI device to perform a polymerization reaction on the dry film on the board surface to form a precise circuit pattern;

[0081] S4.2. Use a 1.0% sodium carbonate solution to develop the exposed dry film to remove the unreacted dry film;

[0082] S4.3. Inspect the developed dry film to ensure that the circuit pattern is complete and without damage.

[0083] In this embodiment, it should also be noted that the implementation steps of step S5 are as follows:

[0084] S5.1. Set the electroplating parameters, current density and electroplating time according to the actual copper thickness requirements.

[0085] S5.2. Place the sheet material with the first-step copper protected into the electroplating tank and perform the copper electroplating process with the set electroplating parameters.

[0086] S5.3. After electroplating is completed, take out the sheet material and rinse it thoroughly with clean water to remove the residual electroplating solution.

[0087] In this embodiment, it should also be noted that the implementation steps of step S6 are as follows:

[0088] S6.1. Use the chemical micro-etchant to clean and roughen the copper surface again to prepare for the second dry film lamination.

[0089] S6.2. Use the 105°C film laminating process to laminate a new dry film on the board surface to ensure no bubbles and no wrinkles.

[0090] S6.3. Perform a polymerization reaction on the second dry film through the LDI equipment to form the second circuit pattern.

[0091] In this embodiment, it should also be noted that the implementation steps of step S7 are as follows:

[0092] S7.1. Use the 1.0% sodium carbonate process to develop the dry film after the second exposure to remove the unreacted dry film.

[0093] S7.2. Use the chemical etchant to etch the unprotected copper layer to form the second circuit.

[0094] S7.3. Remove all the dry film on the surface to expose the final stepped copper structure.

[0095] Embodiment 2

[0096] Please refer to Figure 1 , in the actual application process, a stepped copper process for a PCB board according to the present invention specifically includes the following steps:

[0097] S1. Raw material preparation and pretreatment:

[0098] S1.1. Use professional cutting equipment to cut the copper clad laminate into sheet materials of the required size according to the design specifications. Among them, the cutting speed is 2 m / min, the cutting pressure is 0.5 MPa, and ensure that the cutting edge is flat and without burrs.

[0099] S1.2. Place the cut sheet metal into the degreasing tank and use an alkaline degreaser to remove the grease and dirt on the sheet surface and in the holes. Among them, the concentration of the degreaser is 5% (mass percentage), the degreasing temperature is 50 ± 5 °C, and the degreasing time is 10 min;

[0100] S1.3. Use an acidic solution to remove the oxide layer on the sheet surface and remove the oxide film on the copper surface. Among them, the solution concentration is 10% (volume percentage), the treatment temperature is 25 ± 3 °C, the treatment time is 5 min until the oxide layer is completely removed, and the rinsing time with clean water is 2 min to ensure no residue;

[0101] S1.4. Use an ultrasonic cleaning device to thoroughly clean the sheet surface to ensure no impurities and no dust. Among them, the ultrasonic frequency is 40 kHz, the cleaning time is 5 min, the drying temperature is 60 ± 5 °C, and the drying time is 10 min;

[0102] S2. Copper deposition and flash plating process:

[0103] S2.1. Place the clean and dry sheet metal into the copper deposition tank and chemically deposit copper ions on the sheet surface to form a thin copper layer;

[0104] Among them, the components of the copper deposition solution are copper salt, reducing agent, complexing agent, the copper deposition temperature is 25 ± 2 °C, and the copper deposition time is adjusted according to the required copper layer thickness. It takes about 10 min to form a 1-μm copper layer;

[0105] S2.2. Prepare an 8 ASF low-current electroplating solution to ensure that the components of the electroplating solution are uniform and the temperature is appropriate;

[0106] Among them, the components of the electroplating solution are copper salt, sulfuric acid, additives (specific ratio according to the electroplating solution formula), the temperature of the electroplating solution is 22 ± 2 °C. Place the sheet metal after copper deposition into the electroplating tank and connect the power supply and electrodes;

[0107] S2.3. Turn on the power supply and perform flash plating at a low current to thoroughly conduct the hole copper and surface copper;

[0108] Among them, the current density is 1 A / dm 2 , and the flash plating time is adjusted according to the required copper layer uniformity and thickness. It takes about 5 min to form a uniform thin copper layer;

[0109] S2.4. According to actual production experience, adjust the additives and concentration in the electroplating solution to improve the adhesion between the copper layer and the substrate. Among them, the types and dosages of additives are adjusted according to the recommendations of the electroplating solution supplier and actual production conditions. Regularly maintain and replace the electroplating solution to ensure stable electroplating effect, and the replacement cycle is 48 hours / time;

[0110] S3. Chemical micro-etching and dry film lamination:

[0111] S3.1. Clean and roughen the copper surface using a chemical micro-etchant to enhance the adhesion between the dry film and the copper surface;

[0112] Among them, the components of the micro-etchant are persulfate and oxidant, the micro-etching temperature is 30 ± 2 °C, and the micro-etching time is adjusted according to the required roughness of the copper surface. It takes about 2 minutes to form a moderate roughness;

[0113] S3.2. Select a suitable type and specification of dry film;

[0114] The thickness of the dry film is selected according to the line accuracy and solder mask requirements. A 25-μm thick dry film is selected, and the dry film is cut into the same size as the board material for standby;

[0115] S3.3. Use a 105 °C film laminating process to precisely laminate the dry film on the board surface to ensure no bubbles and no wrinkles;

[0116] Among them, the film laminating temperature is 105 ± 5 °C, and the film laminating pressure is adjusted according to the type of dry film and the thickness of the board material;

[0117] For example: for a 25-μm dry film and a 0.8-mm board material, the pressure is set to 0.3 MPa, and the film laminating time is adjusted according to the adhesion of the dry film and the size of the board material, generally about 3 minutes;

[0118] S3.4. Inspect the laminated dry film to ensure no damage and no displacement. The inspection method is visual inspection or using an automatic detection device. If there are problems, it is necessary to replace or re-laminate in time;

[0119] S4. LDI imaging and dry film removal:

[0120] S4.1. Use an LDI device to carry out a polymerization reaction on the dry film on the board surface to form a precise circuit pattern;

[0121] The exposure energy is adjusted according to the type of dry film and the line accuracy. For a 25-μm dry film and a fine circuit, the exposure energy is set to 80 mJ / cm 2 ;

[0122] The exposure time is adjusted according to the circuit complexity and the performance of the device. For a simple circuit, it takes about 10 seconds;

[0123] S4.2. Use a 1.0% sodium carbonate solution to develop the exposed dry film to remove the unreacted dry film;

[0124] Among them, the concentration of the developer is 1.0 ± 0.1% (mass percentage), the developing temperature is 30 ± 2 °C, and the developing time is adjusted according to the type of dry film and the line accuracy. For a 25-μm dry film, it takes about 2 minutes;

[0125] S4.3. Inspect the developed dry film to ensure that the circuit pattern is complete and without damage;

[0126] The inspection method is visual inspection or using an automatic detection device;

[0127] Protect the first-step copper area with a protective film or special tape to prevent damage during subsequent processing;

[0128] S5. Electroplate to form the second-step copper:

[0129] S5.1. Set the electroplating parameters, current density and electroplating time, according to the actual copper thickness requirements;

[0130] The current density is adjusted according to the required copper layer thickness and the performance of the electroplating solution. To form a 10-μm copper layer, the current density needs to be set at 2 A / dm 2 , Prepare the electroplating solution to ensure that the composition of the electroplating solution is uniform and the temperature is appropriate. Among them, the temperature of the electroplating solution is 25 ± 2°C;

[0131] S5.2. Place the sheet material with the first-step copper protected into the electroplating tank and perform the copper electroplating process with the set electroplating parameters;

[0132] The electroplating time is adjusted according to the required copper layer thickness and the electroplating speed. To form a 10-μm copper layer, it needs to be electroplated for about 30 minutes;

[0133] During the electroplating process, an intelligent electroplating control system needs to be introduced to monitor the concentration of the electroplating solution and the electroplating speed in real time to improve the electroplating accuracy;

[0134] S5.3. After electroplating is completed, take out the sheet material and rinse it with clean water to remove the residual electroplating solution. Among them, the rinsing time is 5 minutes to ensure no residue;

[0135] Inspect the electroplated copper layer to ensure that the copper layer thickness is uniform and without defects. The inspection method is to measure the copper layer thickness with a thickness gauge and visually inspect the surface quality of the copper layer;

[0136] S6. Formation of the secondary circuit pattern:

[0137] S6.1. Use the chemical micro-etchant again to clean and roughen the copper surface to prepare for the lamination of the secondary dry film;

[0138] The composition and concentration of the micro-etchant are the same as in step S3.1. The micro-etching temperature is 30 ± 2°C and the time is 2 minutes;

[0139] S6.2. Use the 105°C film laminating process to laminate a new dry film on the board surface to ensure no bubbles and no wrinkles;

[0140] The film laminating temperature is 105 ± 5°C, the pressure is 0.3 MPa, the same as in step S3.3, and the time is 3 minutes;

[0141] S6.3. Polymerize the secondary dry film through the LDI device to form the secondary circuit pattern;

[0142] The exposure energy is 80 mJ / cm 2 , and the time is 10 sec, the same as step S4.1;

[0143] Perform graphic compensation design according to the stepped copper thickness to ensure that the circuit pattern is consistent with the actual requirements;

[0144] The compensation method is to adjust using specialized graphic compensation software or manually adjust the exposure parameters;

[0145] S7. Secondary circuit etching and dry film removal:

[0146] S7.1. Develop the dry film after secondary exposure using a 1.0% sodium carbonate process to remove the unpolymerized dry film;

[0147] The developer concentration is 1.0 ± 0.1%, the same as step S4.2, the temperature is 30 ± 2 °C, and the time is 2 min;

[0148] S7.2. Etch the unprotected copper layer using a chemical etchant to form the secondary circuit;

[0149] The etchant composition is to select an acidic etchant, and the specific composition and concentration are determined according to the etching speed and requirements;

[0150] Among them, the etching temperature is 35 ± 2 °C, and the etching time is adjusted according to the required circuit width and depth. It takes about 5 min to etch a circuit with a width of 0.2 Mm and a depth of 0.1 Mm;

[0151] S7.3. Remove all the dry film on the surface to expose the final stepped copper structure;

[0152] The removal method is to soak it with a special dry film stripping solution and then mechanically strip it, and use a cleaner to thoroughly clean the board surface to remove residues and impurities. The cleaner composition is to select an alkaline cleaner, and the specific composition is determined according to the nature of the residues. The cleaning time is 5 min to ensure that the board surface is clean and residue-free;

[0153] S8. Perform conventional outer layer solder mask and silk screen processing, and use an automatic optical inspection device to comprehensively inspect the PCB board to ensure that the circuit and stepped copper structure are correct;

[0154] S9. Vacuum package the qualified PCB boards to prevent moisture absorption or damage during transportation and storage.

[0155] Through the above steps S1 to S9, the present invention adopts a secondary circuit process. The first circuit dry film protects the first-order copper from electroplating, realizing the production of second-order copper and even more-order copper, reducing complex processes and production costs. At the same time, through LDI technology, high-precision circuit pattern production is achieved, ensuring the accuracy and consistency of the circuits;

[0156] The present invention introduces an intelligent electroplating control system during the electroplating process to monitor the electroplating solution concentration and electroplating speed in real time, greatly improving the accuracy and stability of electroplating. The process flow is reasonably designed, the steps are compact, reducing unnecessary waiting time and operations, and improving production efficiency. Processes such as chemical micro-etching and dry film lamination are used to enhance the adhesion between the dry film and the copper surface, reducing quality problems in subsequent processing. The dry film, electroplating solution, and etchant used in the process have wide adaptability and compatibility, suitable for the production of PCB boards with different specifications and requirements. By adjusting parameters such as current density, electroplating time, and etching temperature, the thickness of the copper layer and the width of the circuit are flexibly controlled to meet different design requirements. At the same time, the present invention also ensures the quality and reliability of the PCB board through strict pretreatment, copper deposition, flash plating, electroplating, etching and other steps, and uses automatic optical inspection equipment to comprehensively inspect the PCB board, timely discovering and correcting potential problems, and improving the qualified rate of the finished product

[0157] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0158] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not elaborate all the details, nor limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A PCB board step copper process, characterized in that: The following steps are involved: S1. Cut the raw materials into sheets of required size and perform conventional degreasing and deoxidation pretreatment; S2. Through the copper deposition process, a thin layer of copper is formed on the board surface as the basis for subsequent electroplating, and the flash plating process is performed using 8ASF low current; S3. Turn off the grinding brush, use chemical micro-etching process to clean and roughen the copper surface, enhance the adhesion between the dry film and the copper surface, and use 105℃ lamination process to accurately press the dry film onto the board surface; S4. The dry film on the board surface is polymerized by LDI direct imaging process to form a precise circuit pattern. The dry film that has not been polymerized is removed by 1.0% sodium carbonate solution to retain the polymerization pattern, that is, the first step copper area is protected by the dry film; S5. Since the first-step copper is protected by dry film, this electroplating process is only performed on the area not protected by dry film. The electroplating parameters are set according to the actual copper thickness requirements to ensure that the second-step copper reaches the predetermined thickness. At the same time, an intelligent electroplating control system is introduced to monitor the concentration of the electroplating solution and the electroplating speed in real time; S6. Use chemical micro-etching process to clean and roughen the copper surface again, use 105℃ lamination process to press the new dry film on the board surface, and form the secondary circuit pattern through LDI direct imaging process; S7. Developing using a 1.0% sodium carbonate process, and then removing the unprotected copper layer by a chemical copper etching process to form a secondary circuit, remove all dry films on the surface, and expose the final stepped copper structure; S8. Carry out routine processing of outer layer solder mask and silk screen printing, and use automatic optical inspection equipment to conduct comprehensive inspection of PCB board; S9. Vacuum pack the qualified PCB boards to prevent them from getting damp or damaged during transportation and storage.

2. A PCB board step copper process according to claim 1, characterized in that: The implementation steps of step S1 are: S1.

1. Use cutting equipment to cut the copper clad laminate into sheets of required size; S1.

2. Place the cut sheet into the degreasing tank and use an alkaline degreasing agent to remove grease and dirt from the sheet surface and holes; S1.

3. Use an acidic solution to remove the oxide layer on the board surface to remove the oxide film on the copper surface; S1.

4. Use ultrasonic cleaning equipment to thoroughly clean the board surface.

3. A PCB board step copper process according to claim 2, characterized in that: The implementation steps of step S2 are: S2.

1. Place the clean and dry sheet into the copper deposition tank, and deposit copper ions on the sheet surface by chemical methods to form a thin layer of copper; S2.

2. Prepare 8ASF low current plating solution and ensure that the composition of the plating solution is uniform and the temperature is appropriate; S2.

3. Turn on the power supply and perform flash plating with low current to make the hole copper and surface copper completely conductive; S2.

4. Adjust the additives and concentration in the electroplating solution to improve the bonding strength between the copper layer and the substrate.

4. A PCB board step copper process according to claim 3, characterized in that: The implementation steps of step S3 are: S3.

1. Use chemical microetching agent to clean and roughen the copper surface to enhance the adhesion between the dry film and the copper surface; S3.

2. Select appropriate dry film type and specifications; S3.

3. Use 105℃ lamination process to accurately press the dry film onto the board surface; S3.

4. Inspect the laminated dry film.

5. A PCB board step copper process according to claim 4, characterized in that: The implementation steps of step S4 are: S4.

1. Use LDI equipment to polymerize the dry film on the board surface to form a precise circuit pattern; S4.

2. Developing the exposed dry film using a 1.0% sodium carbonate solution to remove the dry film that has not undergone polymerization; S4.

3. Inspect the dry film after development.

6. A PCB board step copper process according to claim 5, characterized in that: The implementation steps of step S5 are: S5.

1. Set the electroplating parameters, current density and electroplating time according to the actual copper thickness requirements; S5.

2. Place the sheet material with the first step copper protected in the electroplating tank and perform the copper electroplating process according to the set electroplating parameters; S5.

3. After the electroplating is completed, remove the sheet and rinse it with clean water to remove the residual electroplating solution.

7. A PCB board step copper process according to claim 6, characterized in that: The implementation steps of step S6 are: S6.

1. Use chemical microetchant to clean and roughen the copper surface again to prepare for the second dry film lamination; S6.

2. Use 105℃ lamination process to press the new dry film onto the board surface; S6.

3. The secondary dry film is polymerized by LDI equipment to form a secondary circuit pattern.

8. A PCB board stepped copper process according to claim 7, characterized in that: The implementation steps of step S7 are: S7.

1. Develop the dry film after double exposure using a 1.0% sodium carbonate process to remove the dry film that has not undergone polymerization; S7.

2. Etching the unprotected copper layer using a chemical etchant to form a secondary circuit; S7.

3. Remove all dry film from the surface to expose the final stepped copper structure.

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