Processing method of PCB (Printed Circuit Board)
By using methods of continuously applying two dry films, multiple developments, copper plating and film de-film etching in PCB board production, it is solved that the prior art is difficult to produce copper thickness of 6oz and the ratio of line width to copper thickness is 1:1. The problem of PCB board achieves high-precision and high-quality product production.
Patent Information
- Application Number
- CN202411479837.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-02-07
AI Technical Summary
It is difficult to produce PCB boards with a copper thickness of 6oz and a line width to copper thickness ratio of 1:1, and the lines will not be thrown after tin spraying without lead.
By providing 2oz copper clad plate, two layers of dry films are applied continuously, one exposure and two developments are performed, copper plating and tin plating are performed, and two film removal and etching are performed, resulting in a copper thickness of 6oz and line width with PCB board with a copper thickness ratio of 1:1.
The process flow is simplified, the alignment deviation caused by fractional exposure is avoided, the accuracy of the line pattern and the copper plating quality are improved, the problems of imperfect film fading and uneven etching are solved, and the product quality and production efficiency are ensured.
Smart Images
Figure CN119403050A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of PCB board production, and in particular to a method for processing a PCB board. Background Art
[0002] In the PCB industry, the line width design specification is directly affected by the bottom copper thickness. The thicker the bottom copper, the more difficult it is to make fine line patterns. However, according to the current normal production process, it is extremely difficult to obtain a PCB with a copper thickness of 6oz, a line width and copper thickness ratio of 1:1, and no line swinging or deformation after lead-free tin spraying. Summary of the invention
[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a PCB processing method, which can produce a PCB with a copper thickness of 6oz and a line width to copper thickness ratio of 1:1, and does not fall off the line or deform after lead-free tin spraying, meets production requirements, and the production procedure is simple and easy to operate.
[0004] The method for processing a PCB board according to an embodiment of the present application includes: Data preparation: Provide 2oz copper clad laminate; Outer dry film: two layers of a 2 mil thick dry film are continuously pasted on the copper clad laminate to obtain a first substrate with a dry film thickness of 4 mil; Exposure and development: exposing and developing the first substrate twice to obtain a second substrate; Pattern electroplating: copper plating and tin plating are performed twice on the second substrate to obtain a third substrate; Outer layer etching: The third substrate is subjected to two film stripping, two etchings and tin stripping to obtain a PCB board with a copper thickness of 6 oz and a line width to copper thickness ratio of 1:1.
[0005] According to the processing method of the PCB board described in the embodiment of the present application, at least the following beneficial effects are achieved: by continuously pasting two layers of dry film, only one exposure is required at this time, which simplifies the process flow and avoids the alignment deviation caused by the exposure in batches; by performing two developments, the accuracy of the circuit pattern can be improved to ensure the product quality; by performing two copper platings, the probability and size of pinholes caused by long-term electroplating can be reduced, and at the same time, the copper plating thickness can be guaranteed to meet the production requirements and the copper plating quality can be guaranteed; by performing two film strippings, the problems of incomplete film stripping, poor penetration, film clamping, and residual film can be solved, and the subsequent etching effect can be improved; by performing two etchings, the etching uniformity can be good, the line-dense area can be etched cleanly, and the area with fewer lines will not have the problem of excessive etching, thereby improving the quality of the product and reducing the production scrap rate. The processing method of the PCB board described in the embodiment of the present application can produce a PCB board with a copper thickness of 6oz and a line width to copper thickness ratio of 1:1, and there is no line swinging or deformation after lead-free tin spraying, which meets the production requirements, and the production procedure is simple and easy to operate.
[0006] According to the PCB processing method described in the embodiment of the present application, the material preparation includes: cutting, drilling, and copper deposition of a 2oz copper clad board.
[0007] According to the processing method of the PCB board described in the embodiment of the present application, in the outer layer of dry film, the protective film is torn off immediately after the first layer of dry film is pasted, and then the second layer of dry film is pasted.
[0008] According to the PCB processing method described in the embodiment of the present application, the copper clad board is roughened before the first layer of dry film is attached.
[0009] According to the PCB processing method described in the embodiment of the present application, an eight-grid exposure ruler is used for exposure, the first development speed is 2 m / min, and the second development speed is 2.8 m / min.
[0010] According to the processing method of the PCB board described in the embodiment of the present application, the current density of copper plating is 14.5ASF, the copper plating time is 180min, the current density of tin plating is 16ASF, and the tin plating time is 10min.
[0011] According to the PCB board processing method described in the embodiment of the present application, the first film stripping speed is 0.4m / min, the second film stripping speed is 2.5m / min, the etching speed is 5.1m / min, and the tin stripping speed is 2.0-2.5m / min.
[0012] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0014] Figure 1 This is a flow chart of a method for processing a PCB board according to some embodiments of the present application. DETAILED DESCRIPTION
[0015] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0016] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0017] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0018] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation, connection and connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0019] Reference Figure 1 , an embodiment of the present application provides a method for processing a PCB board, including but not limited to step S110, step S120, step S130, step S140 and step S150.
[0020] Step S110, data preparation: providing 2oz copper clad laminate.
[0021] Specifically, the 2oz copper clad laminate is cut, drilled, and copper plated. Furthermore, a production process is formulated to cut the copper clad laminate with a bottom copper thickness of 2oz so that the size of the copper clad laminate meets the production size; then holes are drilled on the cut copper clad laminate, and the position and size of the holes must meet the design requirements to assist in welding the jack components and positioning; finally, a layer of copper is deposited on the copper clad laminate through chemical copper plating to achieve the purpose of connecting the inner and outer layer networks while preparing for the thickening of the copper layer in the subsequent process.
[0022] Step S120, outer layer dry film: continuously attach two layers of dry film with a thickness of 2 mil to the copper clad laminate to obtain a first substrate with a dry film thickness of 4 mil.
[0023] Specifically, a layer of dry film with a thickness of 2 mil is first pasted on the copper clad board. When the first layer of dry film is pasted, the protective film is immediately torn off, and then a second layer of dry film with a thickness of 2 mil is continued to be pasted to obtain a first substrate with a dry film thickness of 4 mil, so as to prepare for the subsequent circuit pattern. By pasting two layers of dry film continuously, only one exposure is required in the subsequent process, which simplifies the process flow, avoids the alignment deviation caused by multiple exposures, and improves product quality.
[0024] It is conceivable that the copper clad laminate is roughened before the first layer of dry film is applied. The contaminants on the copper surface are removed by chemical cleaning and the roughness of the surface is increased, thereby increasing the bonding force between the dry film and the surface of the copper clad laminate. Of course, the surface roughening can also be achieved by grinding the plate, which is not limited in this application.
[0025] Step S130, exposure and development: the first substrate is exposed and developed twice to obtain a second substrate.
[0026] Specifically, the first substrate is irradiated with ultraviolet light by a fully automatic exposure machine, and the required pattern is transferred to the first substrate using red film or black film. After the pattern is transferred, the unexposed dry film is dissolved by sodium carbonate solution, and the exposed part is retained, thereby obtaining a second substrate with the required circuit pattern. Since two layers of dry film are directly attached to the copper clad laminate in the early stage, only one exposure is required, which simplifies the process flow, avoids the alignment deviation caused by multiple exposures, and improves the product quality; at the same time, by performing two developments, the accuracy of the circuit pattern can be improved to ensure product quality.
[0027] In this embodiment, an eight-grid exposure ruler is used for exposure, the speed of the first development is 2 m / min, and the speed of the second development is 2.8 m / min. By adopting the above method, a good circuit pattern can be formed on the second substrate, thereby improving product quality.
[0028] Step S140, pattern electroplating: copper plating and tin plating are performed twice on the second substrate to obtain a third substrate; Specifically, the copper layer of the second substrate is thickened by chemical solution to improve the corrosion resistance of the copper layer, and then tinning is performed to protect the copper surface from being polluted by oxidation and to facilitate welding, thereby obtaining the third substrate. By performing copper plating twice, the probability and size of pinholes generated by long-term electroplating can be reduced, and the copper plating thickness can also be ensured to meet production requirements and ensure the copper plating quality; tinning is performed after copper plating to protect the copper surface from being polluted by oxidation and to facilitate welding, thereby improving product quality.
[0029] In this embodiment, the current density of copper plating is 14.5ASF, the copper plating time is 180min, the current density of tin plating is 16ASF, and the tin plating time is 10min. By adopting the above structure, the copper plating thickness can be better controlled and the product quality can be improved.
[0030] Step S150, outer layer etching: the third substrate is stripped twice, etched twice and tin stripped to obtain a PCB board with a copper thickness of 6 oz and a line width to copper thickness ratio of 1:1.
[0031] Specifically, a strong alkaline solution is used to remove the two layers of dry film on the third substrate to complete the film stripping, and then a strong oxidizing solution is used to etch away the exposed copper, and finally the electroplated anti-corrosion tin layer is removed, thereby obtaining a PCB board with a copper thickness of 6oz and a line width to copper thickness ratio of 1:1, and after lead-free tin spraying, there is no line swinging or deformation, which meets the production requirements, and the production procedure is simple and easy to operate. Among them, the speed of the first film stripping is 0.4m / min, the speed of the second film stripping is 2.5m / min, the speed of etching is 5.1m / min, and the speed of tin stripping is 2.0-2.5m / min. By stripping the film twice, the problems of incomplete film stripping, poor penetration, film clamping, and residual film can be solved, and the subsequent etching effect can be improved; by etching twice, the etching uniformity can be good, the line-dense area can be etched cleanly, and the area with fewer lines will not have the problem of excessive etching, thereby improving the quality of the product and reducing the production scrap rate.
[0032] In some embodiments, after completing step S150, the PCB board needs to be post-processed. Among them, post-processing includes spot testing, molding, FQC, FQA and packaging. The PCB board is electrically tested by flying probe testing to test the electrical conductivity of the PCB board and ensure the quality of the PCB board; then, according to the existing technology and design requirements, the shape is shaped to obtain a PCB board that meets the production requirements; then, according to the acceptance standards and inspection standards, the appearance of the PCB board is checked, and if there are defects, they are repaired in time to ensure that excellent quality control can be provided; then, the appearance, copper thickness, line width, etc. of the PCB board are sampled again to see if they meet the customer's requirements; finally, the PCB board is sealed and packaged according to the required packaging method and packaging quantity, and desiccant and humidity card are placed, and then shipped.
[0033] By continuously applying two layers of dry film, only one exposure is required, which simplifies the process flow and avoids the alignment deviation caused by multiple exposures; by performing two developments, the accuracy of the circuit graphics can be improved to ensure product quality; by performing two copper platings, the probability and size of pinholes caused by long-term electroplating can be reduced, and at the same time, the copper plating thickness can be guaranteed to meet production requirements and the quality of copper plating can be guaranteed; by performing two film strippings, the problems of incomplete film stripping, poor penetration, film clamping, and residual film can be solved, and the subsequent etching effect can be improved; by performing two etchings, the etching uniformity can be improved, the densely lined areas can be etched cleanly, and the areas with fewer lines will not have the problem of excessive etching, thereby improving the quality of the product and reducing the production scrap rate.
[0034] The processing method of the PCB board described in the embodiment of the present application can produce a PCB board with a copper thickness of 6oz and a line width to copper thickness ratio of 1:1, and there is no line swinging or deformation after lead-free tin spraying, which meets the production requirements, and the production procedure is simple and easy to operate.
[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0036] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.
Claims
1. A method for processing a PCB board, characterized in that: include: Data preparation: Provide 2oz copper clad laminate; Outer dry film: two layers of a 2 mil thick dry film are continuously pasted on the copper clad laminate to obtain a first substrate with a dry film thickness of 4 mil; Exposure and development: exposing and developing the first substrate twice to obtain a second substrate; Pattern electroplating: copper plating and tin plating are performed twice on the second substrate to obtain a third substrate; Outer layer etching: The third substrate is subjected to two film stripping, two etchings and tin stripping to obtain a PCB board with a copper thickness of 6 oz and a line width to copper thickness ratio of 1:
1.
2. The method for processing a PCB board according to claim 1, characterized in that: The material preparation includes: cutting, drilling and copper deposition of 2oz copper clad laminate.
3. The method for processing a PCB board according to claim 1, characterized in that: In the outer layer of dry film, the protective film is immediately torn off after the first layer of dry film is pasted, and then the second layer of dry film is pasted.
4. The method for processing a PCB board according to claim 3, characterized in that: Before laminating the first layer of dry film, the copper clad laminate is roughened.
5. The method for processing a PCB board according to claim 1, characterized in that: In the exposure and development, an eight-grid exposure ruler is used for exposure, the speed of the first development is 2 m / min, and the speed of the second development is 2.8 m / min.
6. The method for processing a PCB board according to claim 1, characterized in that: In the pattern electroplating, the current density of copper plating is 14.5ASF, the copper plating time is 180min, the current density of tin plating is 16ASF, and the tin plating time is 10min.
7. The method for processing a PCB board according to claim 1, characterized in that: In the outer layer etching, the first film stripping speed is 0.4 m / min, the second film stripping speed is 2.5 m / min, the etching speed is 5.1 m / min, and the tin stripping speed is 2.0-2.5 m / min.