Circuit board surface treatment method and circuit board

Abstract

The invention discloses a circuit board surface treatment method and a circuit board manufactured by adopting the circuit board surface treatment method. The method comprises the following steps: resistance welding treatment: carrying out resistance welding treatment on a circuit board so as to form a resistance welding protective film on the surface of the circuit board; nickel and gold immersion treatment: nickel and gold immersion treatment is carried out on the circuit board after resistance welding treatment; performing windowing treatment, performing windowing on the circuit board after nickel and gold immersion, and cutting off the solder mask protection film in a partial region so as to expose a first region needing OSP treatment; and OSP processing: carrying out OSP processing on the windowed circuit board so as to form a protection layer in the first area of the circuit board. According to the circuit board surface treatment method provided by the invention, the to-be-solder-resistant film is cut off in a cutting manner, so that the first region needing to be subjected to OSP treatment is directly exposed; according to the method, a traditional film pasting and stripping mode is abandoned, the production efficiency is effectively improved, meanwhile, energy consumption is reduced, and environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit board manufacturing processes, and particularly relates to a method for surface treatment of a printed circuit board and a printed circuit board. Background Art

[0002] In the PCB manufacturing industry, in order to improve the corrosion resistance, solderability, and reliability of a circuit board, it is usually necessary to perform surface treatment on the circuit board. Among them, OSP (organic solderability preservative) treatment is a commonly used surface treatment technology. When the traditional OSP treatment process is applied to a PCB board that has been nickel-gold immersed, it is necessary to first open a window in a specific area to expose the copper surface for OSP treatment.

[0003] However, the existing window opening process often uses the traditional film laminating and stripping method for window opening, which results in a relatively long window opening process flow and high resource consumption, thereby increasing the production cost of the PCB. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a method for surface treatment of a printed circuit board, which can reduce data consumption, shorten the process flow, and reduce the production cost while improving production efficiency.

[0005] The present invention also provides a printed circuit board manufactured by using the above method for surface treatment of a printed circuit board.

[0006] According to the method for surface treatment of a printed circuit board according to the first aspect embodiment of the present invention, the method for surface treatment of a printed circuit board includes the following steps: Solder mask treatment, performing solder mask treatment on the printed circuit board to form a solder mask protective film on the surface of the printed circuit board; Nickel-gold immersion treatment, performing nickel-gold immersion treatment on the printed circuit board after solder mask treatment; Window opening treatment, performing window opening treatment on the printed circuit board after nickel-gold immersion, cutting off the solder mask protective film in some areas to expose a first area that needs to be subjected to OSP treatment; OSP treatment, performing OSP treatment on the printed circuit board after window opening to form a protective layer on the first area of the printed circuit board.

[0007] At least, it has the following beneficial effects: By adopting the circuit board surface treatment method provided in the first aspect of the present invention, the solder mask to be removed is cut off, so as to directly expose the first area to be subjected to OSP treatment. This method abandons the traditional film pasting and stripping method, so this method does not produce pollutants such as industrial wastewater containing organic substances, thereby reducing environmental pollution and being beneficial to protecting the ecological system; at the same time, it can also improve the utilization rate of water resources, save the company's environmental protection treatment costs, and promote green production; furthermore, it can also improve the automation level of circuit board production, reduce the operation of personnel, and the laser cutting process has higher processing accuracy, faster speed and good cutting quality.

[0008] According to some embodiments of the present invention, the solder mask treatment step includes the following steps: Uniformly coat the solder mask ink on the surface of the circuit board; Put the circuit board coated with the solder mask ink into a drying oven for pre-drying to remove the solvent in the ink; Expose and develop the solder mask ink; Put the developed circuit board into a drying oven for drying to cure the solder mask ink and remove the remaining developer; Put the circuit board into a curing furnace for curing so that the solder mask ink reaches a cured state.

[0009] According to some embodiments of the present invention, the nickel immersion and gold plating treatment step includes the following steps: Before performing the nickel immersion and gold plating treatment step, it is necessary to clean the circuit board after the solder mask treatment to remove impurities on the surface of the circuit board; Perform an activation treatment on the cleaned circuit board to form an active catalytic layer on the copper surface of the circuit board; For the nickel immersion and gold plating treatment, put the activated circuit board into a reaction tank and perform nickel immersion and gold plating treatments in sequence; Wash and dry the circuit board after the nickel immersion and gold plating treatment to remove the residual bath solution and impurities on the surface of the circuit board.

[0010] According to some embodiments of the present invention, the window opening treatment step is performed by laser cutting for window opening.

[0011] According to some embodiments of the present invention, the window opening treatment step includes the following steps: Design the window opening pattern. According to the window opening requirements of the circuit board, use computer-aided design software to draw the pattern that needs to be window-opened, and import the drawn window opening pattern into the control system of the laser cutting machine; The laser cutting operation cuts according to a preset windowing pattern and parameters, and the solder mask protection film in some areas is removed to expose the first area that needs to be subjected to OSP treatment.

[0012] According to some embodiments of the present invention, the OSP treatment step includes the following steps: Put the circuit board after windowing into a cleaning tank for cleaning to remove residues on the surface; Put the cleaned circuit board into an OSP treatment tank for OSP treatment to form a layer of the protective layer on the surface of the first area; The circuit board after OSP treatment needs to be cleaned and dried to remove the residual bath solution and moisture on the surface.

[0013] The circuit board according to the embodiment of the second aspect of the present invention is made by using the circuit board surface treatment method of any one of the above first aspects of the present invention.

[0014] It has at least the following beneficial effects: The circuit board made by using the circuit board surface treatment method of any one of the above first aspects of the present invention cancels the traditional method of film pasting and stripping for windowing, which not only effectively improves the production efficiency of the circuit board, but also reduces the production cost of the circuit board. The circuit board surface treatment method provided by the embodiment of the first aspect of the present invention does not produce pollutants such as organic industrial wastewater, thereby reducing environmental pollution and being beneficial to protecting the ecological system; at the same time, it can also improve the utilization rate of water resources, save the company's environmental protection governance cost, and promote green production; furthermore, it can also improve the automation level of circuit board production, reduce personnel operations, and the laser cutting process has higher processing accuracy, faster speed, and good cutting quality.

[0015] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following further describes the present invention with reference to the drawings and embodiments, where: Figure 1 is a schematic flow chart of the circuit board surface treatment method according to the embodiment of the present invention; Figure 2 is a schematic flow chart of other circuit board surface treatment methods according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] In the description of the present invention, it should be understood that when it comes to orientation descriptions, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., it is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0018] In the description of the present invention, if the first and second are described only for the purpose of distinguishing technical features, it should not be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features or implicitly specifying the sequence relationship of the indicated technical features.

[0019] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installation, and connection should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0020] Referring to Figure 1 , according to the circuit board surface treatment method of the first aspect embodiment of the present invention, the circuit board surface treatment method includes the following steps: Solder mask treatment: Perform solder mask treatment on the circuit board to form a solder mask protective film on the surface of the circuit board; Immersion nickel and gold treatment: Perform immersion nickel and gold treatment on the circuit board after solder mask treatment; Window opening treatment: Perform window opening on the circuit board after immersion nickel and gold treatment, and cut off the solder mask protective film in some areas to expose the first area that needs to be subjected to OSP treatment; OSP treatment: Perform OSP treatment on the circuit board after window opening to form a protective layer in the first area of the circuit board.

[0021] The circuit board surface treatment method of the present invention integrates multiple processes such as solder mask treatment, immersion nickel and gold treatment, window opening treatment, and OSP treatment to form an efficient, environmentally friendly, and reliable circuit board surface protection solution. This method not only simplifies the complex steps in the traditional process, improves production efficiency, but also ensures the processing quality and accuracy. By performing solder mask treatment to form a solder mask protective film, it effectively protects the surface of the circuit board from damage during the soldering process; immersion nickel and gold treatment enhances the corrosion resistance and solderability of the circuit board. Window opening treatment uses precise technical means to accurately expose the first area that needs OSP treatment, facilitating subsequent processing. Finally, OSP treatment forms a protective layer in the first area, further improving the reliability and service life of the circuit board. The method of the present invention has the advantages of simple operation process, good processing effect, and low cost, meeting the urgent needs of the PCB manufacturing industry for high efficiency, environmental friendliness, and reliability.

[0022] This embodiment provides a method for surface treatment of a circuit board, and the specific steps are as follows: First, perform solder mask treatment on the circuit board. Select a suitable solder mask ink, and through steps such as coating, pre-drying, exposure, development, and post-drying, form a uniform solder mask protective film on the surface of the circuit board. This protective film can effectively prevent the solder paste or solder from eroding the non-welding area during the welding process.

[0023] Next, perform immersion nickel and gold treatment. On the circuit board after solder mask treatment, form a uniform nickel-gold alloy layer through steps such as activation, nickel deposition, and gold deposition. This alloy layer not only enhances the corrosion resistance and solderability of the circuit board but also provides a good substrate for subsequent windowing treatment.

[0024] Then, perform windowing treatment. Use laser cutting technology to precisely cut windows on the circuit board after immersion nickel and gold treatment. By controlling parameters such as the power, speed, and focal length of the laser, accurately cut the solder mask protective film in the first area that needs OSP treatment to expose the underlying copper surface.

[0025] Finally, perform OSP treatment. Place the circuit board after windowing into the OSP treatment tank, and form a uniform organic solder protection film protective layer in the first area through a chemical reaction. This protective layer has good anti-oxidation, anti-corrosion, and solderability, can effectively protect the copper surface from damage, and improve the reliability and service life of the circuit board.

[0026] Therefore, it can be understood that a method for surface treatment of a circuit board proposed by the present invention has at least the following beneficial effects: By using the method for surface treatment of a circuit board provided in the first aspect of the present invention, the solder mask film to be removed is cut to directly expose the first area that needs OSP treatment. This method abandons the traditional film pasting and stripping method, so this method does not produce pollutants such as industrial wastewater containing organic substances, thereby reducing environmental pollution and being conducive to protecting the ecological system; at the same time, it can also improve the utilization rate of water resources, save the company's environmental protection treatment costs, and promote green production; furthermore, it can also improve the automation level of circuit board manufacturing, reduce manual operations, and the laser cutting process has higher processing accuracy, faster speed, and better cutting quality.

[0027] It should be emphasized that with reference to Figure 2 , in implementing various surface treatment methods on a PCB to cope with different mounting methods at different positions, in addition to the above immersion nickel and gold treatment, other surface treatments such as immersion silver, immersion tin, and solder spraying can all cut the protective film that needs to be removed on the circuit board by using laser cutting. Through this method, the purpose of not producing pollutants such as industrial wastewater, improving the utilization rate of water resources, and improving the automation level of circuit board manufacturing can all be achieved.

[0028] In some embodiments of the present invention, the solder mask treatment step includes the following steps: uniformly coating the solder mask ink on the surface of the circuit board; putting the circuit board coated with the solder mask ink into a drying oven for pre-drying to remove the solvent in the ink; exposing and developing the solder mask ink; putting the developed circuit board into a drying oven for drying to cure the solder mask ink and remove the residual developer; putting the circuit board into a curing furnace for curing to make the solder mask ink reach a cured state.

[0029] Specifically, first, uniformly coat the solder mask ink on the surface of the circuit board. This step can be achieved through processes such as screen printing, roll coating, or spraying to ensure that the solder mask ink can uniformly cover every area of the circuit board that needs to be protected. After coating, put the circuit board coated with the solder mask ink into a drying oven for pre-drying. The purpose of pre-drying is to remove the solvent in the ink, preliminarily cure the ink, and prepare for the subsequent exposure and development steps. The temperature and time settings of the drying oven need to be determined according to the characteristics of the solder mask ink and the material of the circuit board to ensure the effect of pre-drying. Next, expose and develop the solder mask ink. The exposure step is to irradiate the solder mask ink with ultraviolet light or other light sources to cause a chemical reaction to form soluble and insoluble areas. The development step is to use a developer to remove the soluble areas, leaving an insoluble solder mask protection film. The parameters of exposure and development need to be adjusted according to the photosensitivity of the solder mask ink and the design requirements of the circuit board. After development, put the circuit board into a drying oven for drying to cure the solder mask ink and remove the residual developer. This step can ensure that the solder mask protection film firmly adheres to the surface of the circuit board, having good solder resistance and corrosion resistance. Finally, put the circuit board into a curing furnace for curing. The temperature and time settings of the curing furnace need to be determined according to the curing characteristics of the solder mask ink and the heat resistance of the circuit board to make the solder mask ink reach a completely cured state. The cured solder mask protection film will have excellent properties, providing a reliable substrate for subsequent electroless nickel immersion gold treatment, window opening treatment, and OSP treatment.

[0030] In some embodiments of the present invention, the electroless nickel immersion gold treatment step includes the following steps: before performing the electroless nickel immersion gold treatment step, it is necessary to clean the circuit board after the solder mask treatment to remove impurities on the surface of the circuit board; perform an activation treatment on the cleaned circuit board to form an active catalytic layer on the copper surface of the circuit board; perform electroless nickel immersion gold treatment, put the activated circuit board into a reaction tank, and perform electroless nickel and immersion gold treatments in sequence; wash and dry the circuit board after the electroless nickel immersion gold treatment to remove the residual bath solution and impurities on the surface of the circuit board.

[0031] The immersion nickel-gold treatment process is a crucial step in ensuring the good solderability and corrosion resistance of printed circuit boards. Before the immersion nickel-gold treatment, the printed circuit board after solder mask treatment needs to be cleaned first. This cleaning step usually uses deionized water or a special cleaning agent, and through methods such as spraying, immersion, or ultrasonic cleaning, thoroughly removes impurities such as grease, dust, and residual solder mask ink solvent on the surface of the printed circuit board to ensure the smooth progress of subsequent treatments. After cleaning, the printed circuit board is subjected to an activation treatment. The purpose of the activation treatment is to form an active catalytic layer on the copper surface of the printed circuit board to provide a catalytic effect for the subsequent nickel and gold deposition reactions. The activation treatment usually uses an activation solution containing catalytic elements such as palladium and tin, and through the method of immersion or spraying, the catalytic elements are evenly adsorbed on the copper surface. Next, the immersion nickel-gold treatment is carried out. The activated printed circuit board is placed in a reaction tank, and the nickel and gold depositions are carried out in sequence. The nickel deposition is to form a nickel layer on the copper surface through electrochemical or chemical deposition methods. The nickel layer has good corrosion resistance and solderability. Subsequently, the gold deposition is carried out, and also under the action of electrochemical or chemical deposition, a gold layer is formed on the surface of the nickel layer. The gold layer not only has excellent electrical conductivity but also can further enhance the corrosion resistance and solderability of the printed circuit board. After the immersion nickel-gold treatment is completed, the printed circuit board is washed with water and dried. The water washing step uses deionized water and through methods such as spraying or immersion, thoroughly removes the residual bath solution and impurities on the surface of the printed circuit board. The drying step is to thoroughly remove the moisture on the surface of the printed circuit board through methods such as hot air drying or vacuum drying to ensure the cleanliness and dryness of the surface of the printed circuit board and prepare for the subsequent window opening treatment and OSP treatment.

[0032] In some embodiments of the present invention, the window opening treatment step is carried out by using laser cutting for window opening. Specifically, in the implementation, the window opening treatment is carried out by using laser cutting. Laser cutting technology, with its characteristics of high precision, high efficiency, and non-contact processing, is very suitable for the window opening treatment of printed circuit boards. During the operation, first, according to the design requirements of the printed circuit board, the area and shape to be windowed are determined. Then, the printed circuit board is fixed on the workbench of the laser cutting machine, and the parameters of the laser cutting machine, such as laser power, cutting speed, focal length, etc., are adjusted to ensure the cutting accuracy and effect.

[0033] Specifically, in some embodiments of the present invention, the window opening treatment step includes the following steps: designing the window opening pattern, according to the window opening requirements of the printed circuit board, using computer-aided design software to draw the pattern to be windowed, and importing the drawn window opening pattern into the control system of the laser cutting machine; laser cutting operation, cutting according to the preset window opening pattern and parameters, removing the solder mask protection film in some areas, and exposing the first area to be subjected to OSP treatment.

[0034] First, according to the windowing requirements of the circuit board, technicians use computer-aided design software (such as CAD software) to draw the graphics that need to be windowed. This graphic accurately reflects which areas of the solder mask on the circuit board need to be removed for subsequent OSP treatment. After drawing, this windowing graphic is imported into the control system of the laser cutting machine to prepare for the subsequent cutting operation. Next, the laser cutting operation is carried out. In this step, the laser cutting machine cuts according to the preset windowing graphic and parameters. The operator needs to ensure that all parameters of the laser cutting machine (such as laser power, cutting speed, focal length, etc.) have been adjusted to the optimal state to ensure the cutting accuracy and effect. The laser beam will precisely cut off the solder mask on the circuit board according to the contour of the windowing graphic. During this process, the high energy density of the laser beam can quickly melt or vaporize the solder mask, thus forming a clean and flat windowing area. After cutting, part of the solder mask on the circuit board is removed, exposing the first area that needs to be subjected to OSP treatment. The operator can inspect the circuit board to confirm that the position, shape, and size of the windowing area are consistent with the design requirements. If necessary, the windowing area can be further cleaned and processed to ensure the smooth progress of subsequent OSP treatment. Through such precise windowing treatment steps, the present invention can ensure the accuracy and efficiency of the circuit board surface treatment.

[0035] In some embodiments of the present invention, the OSP treatment step includes the following steps: putting the windowed circuit board into a cleaning tank for cleaning to remove surface residues; putting the cleaned circuit board into an OSP treatment tank for OSP treatment to form a protective layer on the surface of the first area; the OSP-treated circuit board needs to be cleaned and dried to remove the residual bath solution and moisture on the surface.

[0036] In the circuit board surface treatment method of the present invention, the OSP treatment step is a key link to ensure a good protective layer in the first area of the circuit board. First, the circuit board after window opening is placed in a cleaning tank for cleaning. The purpose of this step is to remove impurities, oil stains or residues left in the previous treatment steps that may remain on the surface of the circuit board, ensuring that the OSP treatment can be carried out on a clean surface, thereby improving the adhesion and quality of the protective layer. After cleaning, the circuit board is placed in an OSP treatment tank for OSP treatment. The OSP treatment tank contains a specific organic solder mask treatment solution, which can form a dense protective layer with good anti-oxidation and anti-corrosion properties on the copper surface. During the treatment process, parameters such as the temperature and treatment time of the treatment solution need to be controlled to ensure that the protective layer can adhere evenly and firmly to the surface of the first area. After the OSP treatment is completed, the circuit board is cleaned and dried. The cleaning step is to remove the residual OSP treatment solution and other impurities on the surface of the circuit board to avoid adverse effects on the performance of the circuit board. The drying step is to completely remove the moisture on the surface of the circuit board through hot air drying or other drying methods, ensuring that the protective layer can exist stably and providing reliable guarantee for subsequent processing and use. Through such strict OSP treatment steps, the present invention can ensure that the first area of the circuit board obtains a high-quality protective layer, improving the reliability and service life of the circuit board.

[0037] The circuit board according to the embodiment of the second aspect of the present invention is made by using the circuit board surface treatment method of any one of the above-mentioned first aspects of the present invention. The circuit board made by using the circuit board surface treatment method of any one of the above-mentioned first aspects of the present invention cancels the traditional method of film pasting and stripping for window opening, which not only effectively improves the production efficiency of the circuit board, but also reduces the production cost of the circuit board. The circuit board surface treatment method provided by the embodiment of the first aspect of the present invention does not produce pollutants such as industrial waste water containing organic substances, thereby reducing environmental pollution and being beneficial to protecting the ecological system; at the same time, it can also improve the utilization rate of water resources, save the company's environmental protection treatment cost, and promote green production; furthermore, it can also improve the automation level of circuit board manufacturing, reduce the operation of personnel, and the laser cutting process has higher processing precision, faster speed and good cutting quality.

[0038] In addition, specifically, during the production process of this circuit board, first, solder mask treatment is carried out to ensure that the areas on the circuit board that do not require subsequent treatment are effectively protected. Then, through precise window opening treatment, the first areas that need to be subjected to OSP treatment are exposed. Then, OSP treatment is carried out on these first areas to form a dense protective layer, effectively preventing the oxidation and corrosion of the copper surface. During the whole treatment process, auxiliary steps such as cleaning and drying are also included to ensure that each treatment link can be carried out in a clean and controlled environment, thereby improving the overall quality and reliability of the circuit board.

[0039] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0040] Of course, the present invention is not limited to the above embodiments. Those skilled in the art can also make equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for surface treatment of a circuit board, characterized in that, It includes the following steps: Solder mask treatment: Perform solder mask treatment on the circuit board to form a solder mask protective film on the surface of the circuit board; Immersion nickel and gold treatment: Perform immersion nickel and gold treatment on the circuit board after solder mask treatment; Window opening treatment: Perform window opening on the circuit board after immersion nickel and gold treatment, and cut off the solder mask protective film in some areas to expose the first area that needs to be subjected to OSP treatment; OSP treatment: Perform OSP treatment on the circuit board after window opening to form a protective layer on the first area of the circuit board.

2. The surface treatment method of a circuit board according to claim 1, wherein The solder mask treatment step includes the following steps: Uniformly coat the solder mask ink on the surface of the circuit board; Put the circuit board coated with the solder mask ink into a drying oven for pre-drying to remove the solvent in the ink; Expose and develop the solder mask ink; Put the developed circuit board into a drying oven for drying to cure the solder mask ink and remove the residual developer; Put the circuit board into a curing furnace for curing to make the solder mask ink reach a cured state.

3. The surface treatment method of the circuit board according to claim 1, wherein, The immersion nickel and gold treatment step includes the following steps: Before performing the immersion nickel and gold treatment step, it is necessary to clean the circuit board after solder mask treatment to remove impurities on the surface of the circuit board; Perform activation treatment on the cleaned circuit board to form an active catalytic layer on the copper surface of the circuit board; Immersion nickel and gold treatment, put the activated circuit board into a reaction tank and perform immersion nickel and immersion gold treatments in sequence; Wash and dry the circuit board after immersion nickel and gold treatment to remove the residual bath solution and impurities on the surface of the circuit board.

4. The surface treatment method of the circuit board according to claim 1, characterized in that, The window opening treatment step is carried out by means of laser cutting.

5. The surface treatment method of the circuit board according to claim 4, characterized in that, The window opening treatment step includes the following steps: Design the window opening pattern. According to the window opening requirements of the circuit board, use computer-aided design software to draw the pattern that needs to be window-opened, and import the drawn window opening pattern into the control system of the laser cutting machine; Laser cutting operation: Cut according to the preset window opening pattern and parameters, cut off the solder mask protective film in some areas, and expose the first area that needs to be subjected to OSP treatment.

6. The method for surface treatment of a circuit board according to claim 1, wherein The OSP treatment step includes the following steps: Put the circuit board after window opening into a cleaning tank for cleaning to remove the residues on the surface; Put the cleaned circuit board into an OSP treatment tank for OSP treatment to form a layer of the protective layer on the surface of the first area; The circuit board after OSP treatment needs to be cleaned and dried to remove the residual bath solution and moisture on the surface.

7. A circuit board, characterized in that, It is made by using the circuit board surface treatment method described in any one of claims 1 to 6.

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