Anti-seepage plating method for PCB (Printed Circuit Board) electroplating

Abstract

The invention discloses an anti-seepage plating method for PCB electroplating. The anti-seepage plating method comprises the following steps: sealing an electroless copper wire by adopting a physical partition; a continuous closed micro-positive pressure channel is constructed, and a dry film pretreatment process is performed in the closed micro-positive pressure channel, so that a plate which reaches cleanliness and dryness after plate grinding enters a subsequent film pasting and exposure process; an HEPA (High Efficiency Particulate Air) filtering system is arranged in the continuous closed micro-positive pressure channel and is used for filtering tiny particulate matters in air in the channel; and in the film pasting process, the film pasting pressure of the windlass plate machine is set to be 3.0-4.0 bar. According to the anti-seepage plating method for PCB electroplating, the generation of star point diffusion plating is completely eradicated from the source by establishing a clean plate transfer environment and strengthening the initial adhesive force of the dry film.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and specifically to a method for preventing PCB electroplating penetration. Background Technology

[0002] The PCB pattern plating process is as follows: copper plating → dry film pretreatment (plate grinding) → film lamination → exposure → pattern plating. In the PCB pattern plating process, "speckled plating" is a fatal defect that is difficult to predict and control. It directly leads to smaller line gaps, deterioration of electrical performance, and even product scrapping. The industry generally believes the cause lies in the performance of the dry film itself or the pattern plating parameters. However, in practical applications, it is difficult to solve the PCB plating problem by adjusting the dry film and pattern plating process parameters.

[0003] In view of this, the present invention provides a new process to solve the above-mentioned technical problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a PCB electroplating anti-seepage plating method, which eliminates the generation of star-point seepage plating from the root by establishing a clean board flow environment and strengthening the initial adhesion of dry film.

[0005] The technical solution of this invention is:

[0006] A method for preventing PCB electroplating leakage includes:

[0007] The copper plating lines are physically isolated and sealed off.

[0008] A continuous, closed micro-positive pressure channel is constructed, and the dry film pretreatment process is carried out in the closed micro-positive pressure channel, so that the board that has achieved cleanliness and dryness after grinding can enter the subsequent film lamination and exposure process.

[0009] A HEPA filtration system is installed in the continuous, sealed micro-positive pressure channel to filter out tiny particulate matter in the air within the channel.

[0010] In the film application process, the film application pressure of the roller plate machine is set to 3.0-4.0 bar.

[0011] Furthermore, it also includes a board buffer area, which is separated from the sealed micro-positive pressure channel, and the board buffer area uses clean airflow to blow the board surface.

[0012] Furthermore, within the board buffer area, time monitoring is performed on each rack or each board, and an overtime alarm procedure is set.

[0013] Furthermore, the dry film pretreatment process includes cleaning, grinding, micro-etching, activation, and drying steps in sequence.

[0014] Furthermore, after drying, the surface of the board is completely dry, with zero water stains and zero contaminant residue.

[0015] Furthermore, the temperature and depth of the air within the sealed micro-positive pressure channel are controllable.

[0016] Compared with the prior art, the PCB electroplating anti-splating method provided by the present invention has the following advantages:

[0017] I. Production trials revealed that the "resting environment" of PCBs after grinding and before electroplating is a long-overlooked critical factor. Airborne contaminants in the production environment (such as strong oxidizing / alkaline crystalline dust like KMnO4 and KOH from copper plating lines) can fall and adhere to the copper surface. These contaminants slowly erode the interface between the dry film and the copper surface, causing a "hidden" decrease in adhesion. This damage is difficult to detect before electroplating but is amplified in the electroplating solution, eventually causing the plating solution to penetrate the edges of the dry film, forming irregular speckled plating. Traditional methods that only optimize process parameters cannot fundamentally solve the problem of speckled plating. The PCB electroplating anti-spillage method provided by this invention establishes a clean PCB handling environment and strengthens the initial adhesion of the dry film, eliminating speckled plating at its source. This invention elevates "environmental management" to a strategic level of equal importance to "process parameters," addressing a long-standing blind spot and pain point in the industry.

[0018] Second, the PCB electroplating anti-seepage plating method provided by the present invention forms a double insurance by combining the strategy of "prevention" (isolation of pollution) and "treatment" (strengthening adhesion), which greatly improves the robustness and yield of the process.

[0019] Third, the PCB electroplating anti-seepage plating method provided by this invention mainly involves logistics routes and environmental modifications. It does not require the replacement of expensive raw materials or major modifications to the core electroplating equipment, resulting in a high return on investment and easy promotion within the industry. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a comparison diagram showing the effects of circuit patterns produced by the method of this invention and existing technical methods. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below.

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] A method for preventing PCB electroplating leakage includes:

[0025] (1) Use physical barriers to enclose the copper plating wires.

[0026] (2) Construct a continuous closed micro positive pressure channel, and the dry film pretreatment process is carried out in the closed micro positive pressure channel so that the plate after grinding reaches the cleanliness and dryness and enters the subsequent film lamination and exposure process.

[0027] In other words, the entire logistics path of the board from the copper plating line output to the film lamination process takes place within this channel. Specifically, the dry film pretreatment process includes cleaning, board roughening, micro-etching, activation, and drying steps in sequence, and the board surface must be completely dry, with zero water stains and zero contaminant residue after drying.

[0028] By establishing this channel and physically sealing the copper plating line, the board is completely isolated from the high-pollution area of ​​the copper plating line lamp.

[0029] In practical production applications, the ideal situation is that after the boards are dried, they can directly enter the laminating machine for lamination in the shortest and continuous time possible. This reduces unnecessary dwell time and prevents particle sedimentation and trace amounts of chemical vapor adsorption from accumulating on the boards over time. Preferably, for high-end PCB manufacturing processes, the board transport time from the drying outlet to the lamination inlet should be controlled within 30 minutes.

[0030] If a board buffer area must be set up due to a mismatch in production speed, then the board buffer area must meet stricter environmental control requirements, as follows:

[0031] Physical isolation: It should be separated from the closed micro-positive pressure channel to reduce interference from personnel and equipment activities; Directional airflow: Ensure that clean airflow can continuously blow on the surface of the board to prevent sedimentation;

[0032] Time monitoring: Time monitoring is performed on each rack or board entering the buffer area, and an overtime alarm procedure is set.

[0033] (3) A HEPA filtration system is installed in a continuous, closed micro-positive pressure channel to filter out small particulate matter in the air within the channel;

[0034] By introducing a HEPA filtration system, two key features can be achieved: firstly, it can efficiently filter out fine particulate matter in the air within the channel, ensuring that the air entering the channel is clean; secondly, it can control the air pressure within the channel to a slightly positive pressure, effectively preventing the entry of external pollutants and dust. During application, temperature and humidity sensors can be used to detect the temperature and humidity of the air in the channel, and these parameters can be adjusted according to process requirements to meet the environmental conditions of the workpiece.

[0035] (4) In the film application process, the film application pressure of the rolling machine is set to 3.0-4.0 bar to ensure that the dry film forms a stronger mechanical bond with the copper surface at the micro level and improves the adhesion of the dry film.

[0036] The circuit patterns produced using the process of this invention are compared with those produced using existing technologies, such as... Figure 1 As shown, where Figure 1 (a) A schematic diagram of a circuit fabricated using existing processes (exposed to an open environment, standard pressure). Figure 1 (b) A schematic diagram of a circuit pattern produced according to the process of the present invention (flowing in a closed micro-positive pressure cleaning channel, with the film-applying pressure increased to 3.0-4.0 bar). (Comparison) Figure 1 (a) and Figure 1 (b) It is known that the existing process will produce the defect of "star spot penetration", while the process of the present invention can achieve zero defects in star spot penetration.

[0037] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for preventing PCB electroplating leakage, characterized in that, include: The copper plating lines are physically isolated and sealed off. A continuous, closed micro-positive pressure channel is constructed, and the dry film pretreatment process is carried out in the closed micro-positive pressure channel, so that the board that has achieved cleanliness and dryness after grinding can enter the subsequent film lamination and exposure process. A HEPA filtration system is installed in the continuous, sealed micro-positive pressure channel to filter out tiny particulate matter in the air within the channel. In the film application process, the film application pressure of the roller plate machine is set to 3.0-4.0 bar.

2. The PCB electroplating anti-splating method according to claim 1, characterized in that, It also includes a board buffer area, which is separated from the sealed micro-positive pressure channel, and the board buffer area uses clean airflow to blow the board surface.

3. The PCB electroplating anti-splating method according to claim 2, characterized in that, Within the board buffer area, time monitoring is performed on each rack or each board, and an overtime alarm procedure is set.

4. The PCB electroplating anti-splating method according to claim 1, characterized in that, The pretreatment process for dry film includes cleaning, roughening of the grinding plate, micro-etching, activation, and drying steps.

5. The PCB electroplating anti-splating method according to claim 1, characterized in that, After drying, the surface of the board is completely dry, with zero water stains and zero contaminant residue.

6. The PCB electroplating anti-splating method according to claim 1, characterized in that, Within the sealed micro-positive pressure channel, the temperature and depth of the air are controllable.

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