Rigid-flex printed circuit board jointed board processing method and rigid-flex printed circuit board jointed board structure

Abstract

The invention discloses a rigid-flex board jointed board processing method and a jointed board structure thereof, and the processing method comprises the following steps: a circuit board main body is provided, the circuit board main body is provided with a plurality of circuit board areas arranged in an array, the circuit board areas comprise flexible areas and rigid-flex areas, and a bonding area is arranged between every two adjacent circuit board areas; laminating prepregs on the circuit board main body, the prepregs having a plurality of windowing areas arranged in an array, the positions of the windowing areas being in one-to-one correspondence with the positions of the flexible areas; laminating a copper foil on the prepreg, wherein the copper foil is bonded with the rigid-flex combination area and the bonding area through the prepreg; and laminating treatment: laminating by using a laminating machine. The windowing area of the prepreg is optimized from a plurality of circuit board areas in which the whole windowing is arranged correspondingly to a plurality of circuit board areas in which single openings are arranged in a one-to-one correspondence manner, so that the bonding area of the copper foil is increased, and the copper foil is prevented from being fractured due to overlarge stress in a local area.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board manufacturing technology, and in particular to a rigid-flexible board assembly processing method and a rigid-flexible board assembly structure. Background Art

[0002] As electronic products develop towards miniaturization, lightness and multifunctionality, the design of rigid-flex boards is becoming increasingly complex, and the requirements for lamination processes are becoming increasingly higher. During the lamination process, the performance of the prepreg, as a bonding material, directly affects the bonding strength between the FPC and the PCB and the overall stability of the circuit board. Therefore, the prepreg window opening design is an important step in the lamination process, which aims to avoid stress concentration caused by material expansion or contraction during the lamination process, thereby protecting the internal circuit from damage.

[0003] In the existing rigid-flex board lamination process, the size of the prepreg window opening needs to be adjusted according to the specific design of the circuit board. However, in actual production, the prepreg window opening is usually set too large. In this case, the pressure generated during the lamination process can easily act directly on the outer copper foil through the larger opening, causing the copper foil to be subjected to excessive stress in a local area and cracking. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for processing rigid-flexible composite boards, which can prevent the copper foil from being subjected to excessive stress in a local area and being cracked by optimizing the design of the prepreg window opening.

[0005] The present invention also provides a rigid-flexible board assembly structure using the rigid-flexible board assembly processing method.

[0006] According to a method for processing a rigid-flexible board in a first embodiment of the present invention, the method for processing a rigid-flexible board comprises the following steps:

[0007] A circuit board body is provided, wherein the circuit board body has a plurality of circuit board areas arranged in an array, wherein the circuit board areas include a flexible area and a rigid-flexible combination area, and a bonding area is provided between two adjacent circuit board areas;

[0008] Laminating a prepreg on the circuit board body, the prepreg having a plurality of window areas arranged in an array, the positions of the window areas being arranged in one-to-one correspondence with the positions of the flexible areas;

[0009] Laminating a copper foil on the prepreg, wherein the copper foil is bonded to the rigid-flexible bonding area and the bonding area through the prepreg; and

[0010] The lamination process is to stack the processed assembled circuit board body, the prepreg and the copper foil according to the design sequence and then perform lamination using a laminator.

[0011] According to the method for processing rigid-flexible boards in the embodiment of the present invention, there are at least the following beneficial effects: the window area of ​​the prepreg is optimized from multiple circuit board areas arranged corresponding to the entire window to multiple circuit board areas arranged corresponding to a single opening, so that the copper foil can be bonded to the bonding area between two adjacent circuit board areas through the prepreg, thereby increasing the bonding area of ​​the copper foil, and can also be supported by the prepreg, thereby preventing the copper foil from being subjected to excessive stress in a local area and being cracked during the lamination process. Finally, in subsequent wet processes such as electroplating and cleaning processes, it can prevent the infiltration of chemicals into the circuit board from the places where the copper foil is cracked.

[0012] According to some embodiments of the present invention, the step of laminating a copper foil on the prepreg further includes the following steps: window opening treatment, using a CNC machine tool to perform window opening treatment on the prepreg to obtain the window opening area.

[0013] According to some embodiments of the present invention, the lamination step further comprises the following steps:

[0014] Drilling: fixing the circuit board on a workbench of a drilling machine, starting the drilling machine, and drilling holes according to preset hole positions; and

[0015] Electroplating, depositing a layer of metal on the surface of the circuit board.

[0016] According to some embodiments of the present invention, the electroplating includes whole-board electroplating, pattern electroplating and hole wall electroplating.

[0017] According to some embodiments of the present invention, the electroplating step further includes the following step: removing the anti-plating ink used to protect the non-plating area during the electroplating process.

[0018] According to some embodiments of the present invention, the following processing steps are also included:

[0019] Circuit production, forming a desired circuit pattern on the copper foil;

[0020] Printing solder resist ink, coating a layer of solder resist ink on the circuit board; and

[0021] Circuit board silk screen printing, printing marking information on the circuit board.

[0022] According to the second aspect of the embodiment of the present invention, the rigid-flexible board panel structure is manufactured by the rigid-flexible board panel processing method described in any one of the embodiments of the first aspect, and the rigid-flexible board panel structure includes the circuit board body, the circuit board panel, the prepreg sheet and the copper foil, and the circuit board panel is arranged in an array in the circuit board area of ​​the circuit board body.

[0023] The rigid-flexible board puzzle structure according to the embodiment of the present invention has at least the following beneficial effects: According to at least the beneficial effects of the embodiment of the first aspect above, it can be known that the rigid-flexible board puzzle structure is made by the rigid-flexible board puzzle processing method described in any one of the embodiments of the first aspect above, and has a good board surface structure. The copper foil has good flatness and no cracks, which facilitates the smooth progress of subsequent wet processes such as electroplating process and cleaning process, and can reduce the occurrence of scrapped circuit boards.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0026] Figure 1 A schematic diagram of a rigid-flexible board panel structure in the prior art related to the present invention;

[0027] Figure 2 This is a schematic diagram of a rigid-flex board panel structure according to an embodiment of the second aspect of the present invention.

[0028] Reference numerals:

[0029] Circuit board body 1; circuit board area 2; flexible area 3; rigid-flexible combination area 4; bonding area 5; window area 6. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which 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 invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 invention.

[0032] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0033] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0034] Reference Figure 1 to Figure 2 According to a method for processing a rigid-flexible board assembly, the method comprises the following steps: providing a circuit board body 1, the circuit board body 1 having a plurality of circuit board areas 2 arranged in an array, the circuit board area 2 including a flexible area 3 and a rigid-flexible combination area 4, and a bonding area 5 between two adjacent circuit board areas 2; stacking a semi-cured sheet (not shown in the figure) on the circuit board body 1, the semi-cured sheet having a plurality of window areas 6 arranged in an array, and the positions of the window areas 6 are arranged one by one corresponding to the positions of the flexible areas 3; stacking a copper foil (not shown in the figure) on the semi-cured sheet, the copper foil being bonded to the rigid-flexible combination area 4 and the bonding area 5 through the semi-cured sheet; and laminating treatment, stacking the processed circuit board body 1, the semi-cured sheet and the copper foil in the designed order, and then laminating them using a laminator.

[0035] Specifically, the present invention provides a method for processing rigid-flexible board panels, which includes the following specific steps to achieve efficient and accurate rigid-flexible board panel processing. First, a circuit board body 1 is provided. The circuit board body 1 has a plurality of circuit board areas 2 arranged in an array, and each circuit board area 2 includes a flexible area 3 and a rigid-flexible combination area 4. These areas are pre-divided according to the design requirements of the product. In particular, a bonding area 5 is provided between two adjacent circuit board areas 2 so that the copper foil can achieve a good bonding effect on the panel structure on the circuit board body 1 in the subsequent processing steps. Next, a semi-cured sheet is stacked on the circuit board body 1. The semi-cured sheet also has a plurality of window areas 6 arranged in an array, and the positions of these window areas 6 are arranged one by one with the positions of the flexible areas 3 on the circuit board body 1. The design of the window area 6 is to protect the flexible area 3 during the lamination process to prevent it from being affected by unnecessary pressure or heat. Then, a copper foil is stacked on the semi-cured sheet. The copper foil is bonded to the rigid-flexible combination area 4 and the bonding area 5 on the circuit board body 1 through the semi-cured sheet. The purpose of stacking copper foil is to form a conductive layer in the subsequent lamination process, and at the same time to form a good electrical connection with the corresponding area on the circuit board body 1. Finally, lamination is performed. After the processed panels (including the circuit board body 1, the prepreg and the copper foil) are stacked in the designed order, they are laminated using a laminator. During the lamination process, by controlling parameters such as temperature, pressure and time, the copper foil, the prepreg and the circuit board body 1 are tightly bonded together to form the required rigid-flexible board structure. In summary, the rigid-flexible board panel processing method of the present invention realizes efficient and precise rigid-flexible board panel processing by precisely controlling each processing step. This method not only improves production efficiency, but also ensures the quality and performance of the product.

[0036] Therefore, it can be understood that the method for processing rigid-flexible boards according to the embodiment of the present invention has at least the following beneficial effects: the window area 6 of the prepreg is optimized from multiple circuit board areas 2 arranged in correspondence with the entire window to multiple circuit board areas 2 arranged in correspondence with a single opening, so that the copper foil can be bonded to the bonding area 5 between two adjacent circuit board areas 2 through the prepreg, thereby increasing the bonding area of ​​the copper foil, and can also be supported by the prepreg, thereby preventing the copper foil from being subjected to excessive stress in a local area and being cracked during the lamination process. Finally, in the subsequent wet processes such as electroplating and cleaning processes, it can prevent the liquid medicine from penetrating into the circuit board from the place where the copper foil is cracked.

[0037] Reference Figure 2In some embodiments of the present invention, the step of laminating a copper foil on the prepreg further includes the following steps: windowing treatment, using a CNC machine tool to perform windowing treatment on the prepreg to obtain a windowing area 6. Specifically, this step is to perform precise windowing treatment on the prepreg using a CNC machine tool, thereby obtaining the desired windowing area 6. In actual operation, first ensure that the prepreg is in a stable and flat state, and then use the precise control function of the CNC machine tool to perform windowing treatment on the prepreg according to the preset windowing pattern and size; for example, the windowing area 6 covering a whole row of circuit board areas 2 in the prior art can be divided into 9 windowing areas 6 with a length of 955 microns and a width of 801 microns, and the positions thereof are set one by one corresponding to the positions of the circuit board panel structures on the circuit board body 1, so as to protect the flexible area 3 of the circuit board area 2. In this process, the CNC machine tool will accurately remove part of the material on the prepreg to form the desired windowing area 6, while ensuring the integrity and stability of the surrounding materials. This windowing process can effectively facilitate the subsequent lamination of copper foil on the prepreg, ensure good bonding between the copper foil and the prepreg, and further improve the processing quality and performance of the rigid-flex board. At the same time, this step also reflects the exquisite craftsmanship and high precision of this processing method in detail processing.

[0038] In some embodiments of the present invention, the lamination step further includes the following steps: drilling, fixing the circuit board on the workbench of the drilling machine, starting the drilling machine, and drilling according to the preset hole position; and electroplating, depositing a layer of metal on the surface of the circuit board. After the lamination process is completed, the first step is the drilling step. In this step, the circuit board that has been laminated needs to be fixed on the workbench of the drilling machine. When fixing, it is necessary to ensure that the circuit board is stable and does not shake to ensure the accuracy of the drilling. Then, the drilling machine is started to drill according to the preset hole position. During the drilling process, the rotation speed and feed speed of the drilling machine must be controlled to ensure that the drilled hole position is accurate and the hole diameter is appropriate, while avoiding unnecessary damage to the circuit board. After the drilling is completed, the next step is the electroplating step. In this step, a layer of metal needs to be deposited on the surface of the circuit board. First, the electroplating solution and the electroplating equipment must be prepared. Then, the circuit board is immersed in the electroplating solution, and the power is turned on, so that the metal ions in the electroplating solution are deposited on the surface of the circuit board under the action of the electric field. During the electroplating process, the concentration, temperature and plating time of the plating solution must be controlled to ensure that the deposited metal layer is uniform and dense, and at the same time has good bonding with the surface of the circuit board.

[0039] Specifically, in some embodiments of the present invention, electroplating may include whole-board electroplating, pattern electroplating, and hole wall electroplating. When implementing the electroplating step, for the comprehensiveness and meticulousness of electroplating, three steps are specifically included: whole-board electroplating, pattern electroplating, and hole wall electroplating. Whole-board electroplating, this step is to form a uniform metal layer on the surface of the entire circuit board. The circuit board that has been drilled is completely immersed in the electroplating solution, and by controlling the electroplating time and current intensity, it is ensured that the metal ions can be evenly deposited on every part of the circuit board, thereby forming a metal layer with moderate thickness and uniform distribution. Pattern electroplating, this step is to form a specific circuit pattern on the circuit board. Using mask technology, the parts that do not need to be electroplated are covered, and only the parts where the circuit needs to be formed are exposed. Then, the circuit board is immersed in the electroplating solution again for local electroplating. By accurately controlling the electroplating time and current intensity, a clear and accurate circuit pattern can be formed on the exposed part. Hole wall electroplating, this step is to deposit a layer of metal on the hole wall formed after drilling to enhance the bonding force and conductivity between the hole wall and the circuit board. The drilled circuit board is placed in a special electroplating device so that the electroplating solution can fully contact the hole wall. By controlling the electroplating time and current intensity, a uniform and dense metal layer can be formed on the hole wall, thereby effectively improving the quality and performance of the hole wall.

[0040] In some embodiments of the present invention, the electroplating step further includes the following steps: removing the anti-plating ink used to protect the non-plating area during the electroplating process. After the electroplating step is implemented, an important subsequent step is required: removing the anti-plating ink used to protect the non-plating area during the electroplating process. During the electroplating process, in order to protect the non-plating areas on the circuit board from metal deposition, a layer of anti-plating ink will be applied to these areas. After the electroplating is completed, this layer of ink has completed its mission and needs to be completely removed to ensure the neatness of the circuit board and the smooth progress of subsequent processes.

[0041] The steps to remove the anti-plating ink usually include the following steps: Prepare cleaning equipment: Select appropriate cleaning equipment and cleaning agents to ensure that the cleaning process will not damage the circuit board. Clean the circuit board: Put the electroplated circuit board into the cleaning equipment and use a cleaning agent to clean the anti-plating ink. During the cleaning process, the temperature, concentration and cleaning time of the cleaning agent must be controlled to ensure that the ink can be completely removed. Drying: After cleaning, take out the circuit board and dry it to remove residual cleaning agent and moisture. Inspection and repair: Inspect the cleaned circuit board to ensure that all anti-plating ink has been removed. If any residual or damaged parts are found, repair them in time.

[0042] In some embodiments of the present invention, the following processing steps are also included: circuit production, forming the required circuit pattern on the copper foil; printing solder resist ink, coating a layer of solder resist ink on the circuit board; and circuit board silk screen printing, printing marking information on the circuit board. According to the rigid-flexible board assembly processing method of the above embodiment, in addition to the steps described above, the following key processing steps are also included to ensure the integrity and functionality of the circuit board.

[0043] First is the circuit making step. In this step, the required circuit pattern needs to be formed on the copper foil. This is usually achieved through photolithography and etching technology. Specifically, a layer of photoresist is first coated on the copper foil, and then the circuit pattern is transferred to the photoresist using a photolithography machine. Next, the copper foil portion not protected by the photoresist is removed by an etching process, thereby forming the required circuit pattern on the copper foil. Next is the step of printing solder mask ink. In this step, a layer of solder mask ink needs to be coated on the circuit board. The main function of solder mask ink is to protect the circuit pattern on the circuit board from the erosion of the external environment, and to prevent the solder from flowing to the non-soldering area during welding. When applying solder mask ink, it is necessary to ensure that the ink evenly covers the surface of the circuit board and there are no defects such as bubbles and cracks. Finally, there is the circuit board silk screen printing step. In this step, it is necessary to print marking information on the circuit board, such as production date, manufacturer logo, circuit board model, etc. This is usually achieved through screen printing technology. Specifically, a silk screen containing the required marking information is first made, and then the ink is printed on the circuit board through the silk screen. The amount of ink and printing pressure need to be controlled during the printing process to ensure the clarity and accuracy of the marked information.

[0044] Reference Figure 2 According to the second aspect of the present invention, the rigid-flexible board panel structure is manufactured by the rigid-flexible board panel processing method of any one of the first aspects, and the rigid-flexible board panel structure includes a circuit board body 1, a circuit board panel, a prepreg and a copper foil, and the circuit board panels are arranged in an array in the circuit board area 2 of the circuit board body 1. According to at least the beneficial effect of the first aspect of the embodiment, the rigid-flexible board panel structure is manufactured by the rigid-flexible board panel processing method of any one of the first aspects, and has a good board surface structure, and the copper foil has good flatness and no cracks, which is convenient for the subsequent electroplating process, cleaning process and other wet processes to proceed smoothly, and the occurrence of scrapped circuit boards can be reduced.

[0045] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention 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 invention.

Claims

1. A method for processing rigid-flexible board panels, characterized in that: The following steps are involved: A circuit board body is provided, wherein the circuit board body has a plurality of circuit board areas arranged in an array, wherein the circuit board areas include a flexible area and a rigid-flexible combination area, and a bonding area is provided between two adjacent circuit board areas; Laminating a prepreg on the circuit board body, the prepreg having a plurality of window areas arranged in an array, the positions of the window areas being arranged in one-to-one correspondence with the positions of the flexible areas; Laminating a copper foil on the prepreg, wherein the copper foil is bonded to the rigid-flexible bonding area and the bonding area through the prepreg; as well as The lamination process is to stack the processed assembled circuit board body, the prepreg and the copper foil according to the design sequence and then perform lamination using a laminator.

2. The method for processing rigid-flexible board according to claim 1, characterized in that: The step of laminating a copper foil on the prepreg also includes the following steps before: window opening treatment, using a numerically controlled machine tool to perform window opening treatment on the prepreg to obtain the window opening area.

3. The method for processing rigid-flexible board according to claim 1, characterized in that: The lamination process further comprises the following steps: Drilling: fixing the circuit board on a workbench of a drilling machine, starting the drilling machine, and drilling holes according to preset hole positions; and Electroplating, depositing a layer of metal on the surface of the circuit board.

4. The method for processing rigid-flexible board according to claim 3, characterized in that: The electroplating includes whole-board electroplating, pattern electroplating and hole wall electroplating.

5. The method for processing rigid-flexible board panels according to claim 3, characterized in that: The electroplating step further includes the following step: removing the anti-plating ink used to protect areas outside the electroplating area during the electroplating process.

6. The method for processing rigid-flexible board according to claim 1, characterized in that: The following processing steps are also included: Circuit production, forming a desired circuit pattern on the copper foil; Printing solder resist ink, coating a layer of solder resist ink on the circuit board; and Circuit board silk screen printing, printing marking information on the circuit board.

7. A rigid-flexible board structure, characterized in that: The rigid-flexible board panel processing method according to any one of claims 1 to 6 is adopted, and the rigid-flexible board panel structure includes the circuit board body, the circuit board panel, the prepreg and the copper foil, and the circuit board panel is arranged in an array in the circuit board area of ​​the circuit board body.

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