A method for manufacturing a circuit board based on an immobile PP structure

Abstract

The present invention relates to a method for manufacturing a circuit board based on a non-flowing PP structure, which includes the following steps: inner layer processing, and the inner layer processing technology includes blanking, pretreatment, image transfer, circuit etching, optical inspection, copper surface roughening, panel layout, lamination, drilling of tube position holes, and trimming; outer layer processing, and the outer layer processing technology includes drilling, electroplating, hole plugging, sanding belt, image transfer, pattern electroplating, circuit etching, solder mask screen printing; non-flowing PP window opening, adding a margin of 0.4 mm - 0.5 mm on the basis of the standard window opening size; non-flowing PP lamination, adopting the PINLAM positioning method and jointly laminating with the use of a release film, a PE film, a backing plate, and a silica gel pad; solder mask, covering the outermost layer with a protective layer again by using the solder mask screen printing process; drying and forming, drying the solder mask ink and then performing surface treatment and outer contour processing to obtain a finished product. It improves the problems of glue dots, lamination voids, and broken holes in the non-flowing PP layer that are prone to occur in the circuit board made of this non-flowing PP material.

Description

Technical Field

[0001] The present invention relates to the field of circuit board manufacturing, and particularly to a circuit board manufacturing method based on a non-flowing PP structure. Background Art

[0002] A circuit board, also known as a printed circuit board (PCB), etc., is a provider for electrical connection of electronic components. Its design is mainly layout design; the main advantages of using a circuit board are greatly reducing wiring and assembly errors, and improving the automation level and production labor rate. According to the number of layers of the circuit board, it can be divided into single-sided boards, double-sided boards, four-layer boards, six-layer boards, and other multi-layer circuit boards.

[0003] Polypropylene, abbreviated as PP, is a colorless, odorless, non-toxic, semi-transparent solid substance. Polypropylene (PP) is a thermoplastic synthetic resin with excellent properties, and is a colorless semi-transparent thermoplastic lightweight general-purpose plastic. It has chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties, and good high-abrasion processing properties, etc. Since its advent, polypropylene has been rapidly developed and applied in many fields such as machinery, automobiles, electronic appliances, printed circuit boards, construction, textiles, packaging, agriculture, forestry, fishery, and the food industry.

[0004] "Non-flowing" is the biggest characteristic of non-flowing PP, and it has better mechanical strength compared to ordinary PP; since the board needs to leave welding points and pads, the PP needs to be windowed, so low fluidity and glue overflow are required, and good toughness and machinability are also needed. Currently, the commonly used non-flowing PP has two types: general Tg and high Tg, mainly for supporting use. To improve the electrical performance of the printed circuit board, high Tg non-flowing PP is usually selected.

[0005] Currently, the technology of non-flowing PP structure is lacking. In the existing technology, it is mainly used to solve the problem of warped boards. However, due to the characteristics of non-flowing PP, problems such as pressing voids occur during the pressing process. And the existing technology will also cause problems such as perforation of non-flowing PP and the problem of glue dots on the surface of the product after pressing. Summary of the Invention

[0006] To solve the above problems, the present invention adopts the following technical solutions: A circuit board manufacturing method based on a non-flowing PP structure, including the following steps:

[0007] S1. Inner layer processing. The inner layer processing technology includes blanking, pretreatment, image transfer, circuit etching, optical inspection, copper surface roughening, panel layout, pressing, drilling of tube position holes, and trimming. Using the board material substrate, through copper layer pattern etching, alignment of each layer of board material and copper-clad film, and under the cooperation of controlled heat, an interlayer stack is formed. After trimming, the inner layer manufacturing process is completed, providing a basis for the conduction between the outer layer circuits;

[0008] S2. Outer layer processing. The outer layer processing technology includes drilling, electroplating, hole plugging, sanding belt, image transfer, pattern electroplating, circuit etching, and solder mask screen printing. Using the base material of the inner layer process board that has been completed, drill holes to penetrate the inner layer circuits, electroplate to interconnect and thicken the copper layer, perform pattern etching, and the copper surface protection process;

[0009] S3. Non-flowing PP window opening. Add a margin of 0.4 mm - 0.5 mm on the basis of the standard window opening size;

[0010] S4. Non-flowing PP lamination. Adopt the PINLAM positioning method and cooperate with the use of release film, PE film, backing plate, and silicone pad for co-lamination;

[0011] S5. Solder mask. Use the solder mask screen printing process to cover the protective layer again on the outermost layer;

[0012] S6. Drying and forming. After drying the solder mask ink, perform surface treatment and outer contour processing and forming to obtain the finished product.

[0013] Further, in the S3 step, multiple layers of soft PP are stacked together for processing, and a copper-free core layer is added between adjacent two PP layers to avoid adhesion.

[0014] Further, the PP layers and copper-free core layers stacked alternately are pre-processed by drilling positioning holes.

[0015] Further, in the S4 step, the release film, PE film, backing plate, and silicone pad all undergo the process of punching pin holes.

[0016] Further, in the S4 step, when laminating, wipe one side of the copper surface of the non-flowing PP layer with wax cloth.

[0017] Further, the hole plugging in the S2 step uses resin material to prevent the non-flowing PP layer from having broken holes during the hot air solder leveling surface treatment process.

[0018] Further, the sanding belt in the S2 step is a flexible abrasive tool for pre-grinding treatment.

[0019] The working principle of the present invention is as follows: In order to enhance the comprehensive performance of the circuit board with a non-flowing PP structure and reduce many problems existing in the board manufacturing process, the present invention has made improvements on the basis of the original circuit board process. First of all, the board manufacturing process is generally divided into inner layer processing and outer layer processing. Inner layer processing uses the board material substrate, through copper layer pattern etching, alignment of each layer of board material and copper-clad film, and forms an interlayer stack under the cooperation of controlled heat, and completes the inner layer manufacturing process after trimming, providing a basis for the conduction between the outer layer circuits. The outer layer processing uses the board material substrate of the inner layer process that has been completed, drills holes and penetrates the inner layer circuits, electroplates the copper layer for interconnection and thickening, pattern etching, and copper surface protection process. At the same time, the outer layer process should also include outer contour processing, reliability testing, finished product testing, etc.

[0020] Inner layer processing, the inner layer processing technology includes blanking, pretreatment, image transfer, circuit etching, optical inspection, copper surface roughening, board layout, lamination, drilling of tube position holes, and trimming. It mainly constructs the internal structure of the board, and the present invention follows the main body of the traditional process.

[0021] Outer layer processing, the outer layer processing technology includes drilling, electroplating, hole plugging, sanding belt, image transfer, pattern electroplating, circuit etching, solder mask screen printing. It processes the outer layer of the board. It includes drilling through holes and forming a path by electroplating copper deposition. After preliminary sanding belt pre-grinding, preliminary solder mask printing is carried out to facilitate subsequent processes such as window opening. It is worth mentioning that since the non-flowing PP material is used in the present invention, considering the hole covering position of the non-flowing PP layer, hole plugging treatment is required after drilling the through holes to avoid the problem of hole breakage of the non-flowing PP layer during the processing of the hot air solder leveling surface process. At the same time, due to the insufficient strength of the green oil, the ink will be stressed and separated from the hole wall during the lamination process. Therefore, the material for hole plugging is selected as resin material.

[0022] Non-flowing PP milling window opening, when processing the milling window opening, in the program design, it is necessary to have an extra 0.4 - 0.5 mm compared to the window opening position in the original gerber data to prevent the glue from flowing to the adjacent copper pads or holes during the lamination process. During the milling window opening process, the milling cutter rotates at a high speed, and multiple soft-textured PP layers are stacked together for processing. If the glue cannot be discharged during the milling process, there will be an adhesion problem caused by the milling of the window opening position being blurred. Therefore, a copper-free core layer is added between every two adjacent PP layers to reduce the glue amount of each layer and avoid adhesion.

[0023] However, due to the lack of effective positioning during the milling process, only fixed with paper tape around, the non-flowing PP structure after milling is prone to large alignment deviation when laminated with the product. Therefore, before the lamination process, the non-flowing PP layer and the copper-free core layer are first subjected to punching processing, and the punching position is kept consistent with the alignment target position of the laminated product. By improving the positioning method, compared with the alignment of the processed PP sheet and the product, the alignment accuracy is significantly improved, which can meet the requirements of product lamination.

[0024] Pressing of non-flowing PP. For this product, the PINLAM positioning method is selected for pressing, and auxiliary materials such as release film, PE film, backing plate, and silicone pad are required. Release film: It plays an isolating role during the pressing process, separating the non-flowing PP layer from the silicone pad or steel plate to avoid contamination, and it can be easily separated without adhesion after pressing. The release film needs to be punched with pin holes before use for laminating. PE film: It plays a role of covering the mold during the pressing process, assisting the non-flowing PP layer to fill the circuit pattern under uniform pressure. Before use, the PE film also needs to be punched. It should be noted that the size of the PE film should be close to the size of the production board. If it is too large, it is easy to cause glue flow and contaminate the steel plate; if it is too small, it will lead to insufficient coverage area and cause pressing voids.

[0025] Finally, after the solder mask process covers the solder mask ink layer again, it is dried and then surface treated and outer contour processed to obtain the finished circuit board.

[0026] It should be noted that there may be glue dots on the surface of the product after pressing. Therefore, pressing should be carried out immediately after brownification, and the copper surface on one side of the non-flowing PP layer should be cleaned with wax cloth during lamination. This can effectively reduce the generation rate of glue dots.

[0027] The beneficial effects of the present invention are as follows: While enhancing the electrical performance and mechanical strength of the circuit board through the characteristics of the non-flowing PP material, the original advantage of low warpage rate is retained, and the problems of glue dots, pressing voids, and broken holes in the non-flowing PP layer that are prone to occur in the circuit board made of this non-flowing PP material are further improved through the improvement of the board manufacturing process. Description of the Drawings

[0028] The drawings further illustrate the present invention, but the embodiments in the drawings do not constitute any limitation to the present invention.

[0029] Figure 1 It is a flowchart of a method for manufacturing a circuit board based on a non-flowing PP structure provided by an embodiment of the present invention. Detailed Embodiments

[0030] As Figure 1 shown, a method for manufacturing a circuit board based on a non-flowing PP structure provided by an embodiment of the present invention includes the following steps:

[0031] S1. Inner layer processing. The inner layer processing technology includes blanking, pretreatment, image transfer, circuit etching, optical inspection, copper surface roughening, board layout, pressing, drilling of tube position holes, and trimming. Using the board material substrate, through the etching of the copper layer pattern, the alignment of each layer of board material and copper-clad film, and the formation of an interlayer stack under the cooperation of controlled heat, the inner layer manufacturing process is completed after trimming, providing a basis for the conduction between the outer layer circuits;

[0032] S2. Outer layer processing. The outer layer processing technology includes drilling, electroplating, hole plugging, sanding belt, image transfer, pattern electroplating, circuit etching, and solder mask screen printing. Using the base material of the inner layer process board that has been completed, drill holes to penetrate the inner layer circuits, electroplate to interconnect and thicken the copper layer, perform pattern etching, and copper surface protection process;

[0033] S3. Non-flowing PP window opening. Add a margin of 0.4 mm - 0.5 mm on the basis of the standard window opening size;

[0034] S4. Non-flowing PP lamination. Adopt the PINLAM positioning method and cooperate with the use of release film, PE film, backing plate, and silicone pad for co-lamination;

[0035] S5. Solder mask. Use the solder mask screen printing process to cover the protective layer again on the outermost layer;

[0036] S6. Drying and forming. After drying the solder mask ink, perform surface treatment and outer contour processing and forming to obtain the finished product.

[0037] Furthermore, in the S3 step, multiple layers of soft-textured PP are stacked together for processing, and a copper-free core layer is added between adjacent two layers of PP layers to avoid adhesion.

[0038] Furthermore, the PP layers and copper-free core layers stacked alternately are pre-processed by drilling positioning holes.

[0039] Furthermore, in the S4 step, the release film, PE film, backing plate, and silicone pad all undergo the process of punching pin holes.

[0040] Furthermore, in the S4 step, when laminating, wipe one side of the copper surface of the non-flowing PP layer with wax cloth.

[0041] Furthermore, the hole plugging in the S2 step uses resin material to prevent the non-flowing PP layer from breaking holes during the hot air solder leveling surface treatment process.

[0042] Furthermore, the sanding belt in the S2 step is a flexible abrasive tool for pre-grinding treatment.

[0043] In order to enhance the comprehensive performance of the circuit board with a non-flowing PP structure and reduce many problems existing in the circuit board manufacturing process. The present invention has made improvements on the basis of the original circuit board process. First, the board manufacturing process is generally divided into inner layer processing and outer layer processing. Inner layer processing utilizes the board material substrate, through copper layer pattern etching, alignment of each layer of board material and copper-clad film, and forms an interlayer stack under the cooperation of controlled heat, and completes the inner layer manufacturing process after trimming, providing a basis for the conduction between the outer layer circuits. And outer layer processing utilizes the board material substrate of the inner layer process that has been completed, drills holes and penetrates the inner layer circuits, electroplates copper layers for interconnection and thickening, pattern etching, and copper surface protection process. At the same time, the outer layer process should also include outer contour processing, reliability testing, finished product testing, etc.

[0044] Inner layer processing, the inner layer processing technology includes blanking, pretreatment, image transfer, circuit etching, optical inspection, copper surface roughening, board arrangement, lamination, drilling of tube position holes, and trimming. It mainly constructs the internal structure of the board, and the present invention follows the main body of the traditional process.

[0045] Outer layer processing, the outer layer processing technology includes drilling, electroplating, hole plugging, sanding belt, image transfer, pattern electroplating, circuit etching, solder mask screen printing. It processes the outer layer of the board. It includes drilling through holes and forming a conduction path by electroplating copper deposition. After preliminary sanding belt pre-grinding, preliminary solder mask printing is carried out to facilitate subsequent processes such as window opening. It is worth mentioning that since the non-flowing PP material is used in the present invention, considering the hole covering position of the non-flowing PP layer, hole plugging treatment needs to be carried out after drilling the through holes to avoid the problem of broken holes in the non-flowing PP layer during the processing of the solder spraying surface process. At the same time, because the green oil strength is insufficient, the ink will be stressed and separated from the hole wall during the lamination process. Therefore, the hole plugging material is selected as resin material.

[0046] Non-flowing PP milling window opening, during the processing of milling window opening, in terms of program design, it is necessary to have 0.4 - 0.5 mm more than the window opening position in the original gerber data to prevent the glue from flowing to the adjacent copper pads or holes during the lamination process. During the milling window opening process, the milling cutter rotates at a high speed, and multiple soft-textured PP layers are stacked together for processing. If the glue cannot be discharged during the milling process, there will be an adhesion problem caused by milling the window opening position into a paste. Therefore, a copper-free core layer is added between every two adjacent PP layers to reduce the glue amount of each layer and avoid adhesion.

[0047] However, due to ineffective positioning during the milling process, only fixed with paper tape around, the non-flowing PP structure after milling is prone to large alignment deviation when laminated with the product. Therefore, before the lamination process, the non-flowing PP layer and the copper-free core layer are first subjected to punching processing, and the punching position is kept consistent with the alignment target position of the laminated product. Through the improvement of the positioning method, compared with the alignment of the processed PP sheet and the product, the alignment accuracy is significantly improved, which can meet the requirements of product lamination.

[0048] Pressing of non-flowing PP. For the pressing of this product, the PINLAM positioning method is selected, and auxiliary materials such as release film, PE film, backing plate, and silicone pad are required. Release film: It plays an isolating role during the pressing process, which can isolate the non-flowing PP layer from the silicone pad or steel plate to avoid contamination, and it can be easily separated without adhesion after pressing. The release film needs to be punched with pin holes before use for lamination. PE film: It plays a role of covering the mold during the pressing process, assisting the non-flowing PP layer to fill the circuit pattern under uniform pressure. Before using the PE film, it also needs to be punched. It should be noted that the size of the PE film should be close to the size of the production board. If it is too large, it is easy to cause glue flow and contaminate the steel plate; if it is too small, it will lead to insufficient coverage area and cause pressing voids.

[0049] Finally, after the solder mask process covers the solder mask ink layer again, it is dried and then surface-treated and outer contour processed to obtain the finished circuit board.

[0050] It should be noted that there may be glue dots on the surface of the product after pressing. Therefore, pressing should be carried out immediately after brownification, and the copper surface on one side of the non-flowing PP layer should be cleaned with wax cloth during lamination. This can effectively reduce the generation rate of glue dots.

[0051] While enhancing the electrical performance and mechanical strength of the circuit board through the characteristics of the non-flowing PP material, the advantages of the original low warpage rate are retained, and the problems of glue dots, pressing voids, and broken holes in the non-flowing PP layer that are prone to occur in the circuit board made of this non-flowing PP material are further improved through the improvement of the board manufacturing process.

[0052] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the core technology research and development of the big data server system template based on the purley platform of this invention patent should be subject to the appended claims.

Claims

1. A method for manufacturing a circuit board based on an immobile PP structure, characterized in that, The steps include the following: S1. Inner layer processing. The inner layer processing technology includes blanking, pretreatment, image transfer, circuit etching, optical inspection, copper surface roughening, panel layout, lamination, drilling of tube position holes, and trimming. Using the sheet material substrate, through copper layer pattern etching, alignment of each layer of sheet material and copper-clad film, and forming an interlayer stack under the cooperation of controlled heat, the inner layer manufacturing process is completed after trimming treatment, providing a basis for the conduction between the outer layer circuits; S2. Outer layer processing. The outer layer processing technology includes drilling, electroplating, hole plugging, sanding belt, image transfer, pattern electroplating, circuit etching, solder mask screen printing. Using the sheet material substrate of the completed inner layer process, drilling is carried out to penetrate the inner layer circuits, electroplating the copper layer for interconnection and thickening, pattern etching, and copper surface protection process; Resin material is used for hole plugging to prevent the non-flowing PP layer from breaking holes during the hot air solder leveling surface treatment process; S3. Milling the opening of non-flowing PP, adding a margin of 0.4 mm - 0.5 mm on the basis of the standard opening size; S4. Laminating non-flowing PP, adopting the PINLAM positioning method, and jointly laminating with the release film, PE film, backing plate, and silica gel pad; When laminating, wipe the copper surface on one side of the non-flowing PP layer with wax cloth; S5. Solder mask, using the solder mask screen printing process to cover the protective layer again on the outermost layer; S6. Drying and forming, drying the solder mask ink and then carrying out surface treatment and outer contour processing and forming to obtain the finished product.

2. The method for manufacturing a circuit board based on an immobile PP structure according to claim 1, wherein: In the step S3, multiple soft-textured PP layers are stacked together for processing, and a copper-free core layer is added between adjacent two PP layers to avoid adhesion.

3. The method for manufacturing a circuit board based on the immobile PP structure according to claim 2, wherein: Multiple stacked PP layers and copper-free core layers are pre-drilled for positioning hole processing.

4. The method for manufacturing a circuit board based on the non-flowing PP structure according to claim 1, wherein: In the step S4, the release film, PE film, backing plate, and silica gel pad all undergo the process of punching pin holes.

5. The method for manufacturing a circuit board based on the non-flowing PP structure according to claim 1, characterized in that: The sanding belt in the step S2 is a flexible abrasive tool for pre-grinding treatment.

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