Single-sided flexible wiring board and method for manufacturing the same

Abstract

The application discloses a single-sided flexible circuit board and a manufacturing method thereof. The method comprises the following steps: providing a roll material double-sided board; exposing and developing both sides to form a circuit exposure pattern on the first side and not expose the second side, obtaining a double-sided board to be etched; etching both sides to obtain a semi-finished product roll material circuit board; according to preset protection film parameters, pasting a protection film on the first side of the semi-finished product roll material circuit board and carrying out single cutting to obtain a plurality of single double-sided boards; exposing and developing both sides of each single double-sided board so that the protection film on the first side is not exposed and the second side is exposed, obtaining a semi-finished product single-sided board corresponding to each single double-sided board; etching both sides of each semi-finished product single-sided board to obtain a plurality of single-sided flexible circuit boards. Based on the support of the roll material double-sided board before etching and the protection film after etching, the application can effectively avoid problems such as wrinkles and abnormal expansion and contraction.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board manufacturing, specifically to a single-sided flexible circuit board and its manufacturing method. Background Technology

[0002] As electronic devices become lighter, more portable, and more multifunctional, flexible printed circuit boards (FPCs) are gradually becoming key components in fields such as smartphones, tablets, wearable devices, automotive electronics, and medical devices due to their advantages of being thin, flexible, bendable, and capable of achieving high-density integrated circuit wiring within limited space. They have broad application prospects.

[0003] Compared to double-layer and multi-layer flexible circuit boards, single-sided flexible circuit boards (SPCs) have a simpler structure, lower manufacturing cost, and better bending resistance. Single-sided FPCs mainly consist of a flexible substrate, conductive lines, and a protective film. They are typically used in applications with simple circuit connections, such as keyboards, cables, and simple sensor modules. Single-sided FPCs effectively save space and weight, making them particularly important in portable electronic devices. Furthermore, because the conductive layer is only on one side, single-sided FPCs have greater flexibility and are less prone to breakage, meeting the needs of applications requiring high flexibility and bending resistance.

[0004] However, single-sided FPCs still face many challenges in actual production. Especially in roll-to-roll processes, due to their thinness, they are highly susceptible to uneven tension and pressure during transport, humidity variations, and temperature control changes in the production equipment, leading to problems such as wrinkles and abnormal expansion / contraction. These issues not only affect the product's appearance but can also cause unstable circuit performance and even directly result in product scrap.

[0005] Therefore, developing a new production process that can effectively avoid wrinkles and abnormal expansion and contraction is of great significance for improving the production quality and efficiency of single-panel panels. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a single-sided flexible circuit board and a method for manufacturing the same, in order to solve the problems of product wrinkling and abnormal expansion and contraction that are easily encountered in the existing single-sided flexible circuit board manufacturing technology.

[0007] This invention provides a method for manufacturing a single-sided flexible circuit board, the method comprising:

[0008] Double-sided rolls are available;

[0009] Both sides of the roll double-sided panel are exposed and developed to form a circuit exposure pattern on the first side of the roll double-sided panel, while the second side of the roll double-sided panel is not exposed, thus obtaining the double-sided panel to be etched.

[0010] Etching is performed on both sides of the double-sided board to be etched to obtain a semi-finished roll circuit board.

[0011] According to the preset protective film application parameters, a protective film is applied to the first side of the semi-finished roll circuit board, and the semi-finished roll circuit board after applying the protective film is cut into individual sheets to obtain multiple single double-sided boards.

[0012] Both sides of each single double-sided board are exposed and developed so that the protective film on the first side of each single circuit board is not exposed, and the second side of each single circuit board is exposed, to obtain a semi-finished single board corresponding to each single double-sided board.

[0013] Both sides of each of the semi-finished single-sided boards are etched to obtain multiple single-sided flexible circuit boards.

[0014] Optionally, the exposure and development of both sides of the roll double-sided panel, such that a circuit exposure pattern is formed on the first side of the roll double-sided panel and the second side of the roll double-sided panel is not exposed, to obtain the double-sided panel to be etched, includes:

[0015] A first negative photosensitive dry film is applied to both sides of the double-sided sheet of the roll material using a hot roller pressing method.

[0016] A first transparent film without a circuit pattern and an exposed film with a circuit pattern are provided respectively;

[0017] The first side of the roll double-sided panel is exposed and developed using the exposure film, so that the first negative photosensitive dry film on the first side of the roll double-sided panel is partially dissolved to form the exposed circuit pattern.

[0018] The second side of the roll double-sided panel is exposed and developed using the first transparent film, so that the first negative photosensitive dry film on the second side of the roll double-sided panel is not dissolved, so that the second side of the roll double-sided panel is not exposed, thus obtaining the double-sided panel to be etched.

[0019] Optionally, both sides of the double-sided sheet of the roll are conductive layers;

[0020] The etching process involves etching both sides of the double-sided panel to obtain a semi-finished roll circuit board, including:

[0021] Based on the circuit exposure pattern, the first side of the double-sided board to be etched is etched, so that the conductive layer on the first side of the circuit board to be etched forms a circuit layer.

[0022] The second side of the double-sided board to be etched is etched so that the conductive layer on the second side of the circuit board to be etched is completely preserved.

[0023] Remove the first negative photosensitive dry film from both sides of the etched double-sided board to obtain the semi-finished roll circuit board with single-sided circuitry.

[0024] Optionally, both sides of the double-sided sheet of the roll are conductive layers;

[0025] The step of exposing and developing both sides of each of the single double-sided boards, so that the protective film on the first side of each single circuit board is not exposed, and the second side of each single circuit board is exposed, includes:

[0026] Using a vacuum lamination method, a second negative photosensitive dry film is laminated onto both sides of each single double-sided panel according to preset lamination parameters;

[0027] A second transparent film without a line pattern and a pure black film are provided respectively;

[0028] The second transparent film is used to expose and develop the first side of each single double-sided panel, so that the second negative photosensitive dry film on the first side of each single double-sided panel is completely not dissolved, so that the protective film on the first side of each single double-sided panel is not exposed.

[0029] The second side of each single double-sided panel is exposed and developed using the pure black film, so that the second negative photosensitive dry film on the second side of each single double-sided panel is completely dissolved, thereby exposing the conductive layer on the second side of each single double-sided panel, to obtain the semi-finished single panel corresponding to each single double-sided panel.

[0030] Optionally, etching is performed on both sides of each of the semi-finished single-sided panels to obtain multiple single-sided flexible circuit boards, including:

[0031] The first side of each of the semi-finished single panels is etched so that the protective film on the first side of each of the semi-finished single panels is retained.

[0032] The second side of each of the semi-finished single-sided panels is etched so that the conductive layer on the second side of each of the semi-finished single-sided panels is etched away.

[0033] The second negative photosensitive dry film on the first side of each semi-finished single-sided board after etching is removed to obtain a plurality of the single-sided flexible circuit boards.

[0034] Optionally, the preset dry film parameters include the second negative photosensitive dry film thickness, vacuuming time, first vacuum degree, pressing time, and second vacuum degree; wherein, the first vacuum degree refers to the vacuum degree during the vacuuming process when vacuum pressing film is applied, and the second vacuum degree refers to the vacuum degree during the pressing process when vacuum pressing film is applied.

[0035] Optionally, the thickness of the second negative photosensitive dry film ranges from 25 to 55 μm; and / or, the vacuuming time ranges from 5 to 20 s; and / or, the first vacuum degree is less than or equal to 20 Hpa; and / or, the pressing time ranges from 5 to 15 s; and / or, the second vacuum degree is less than or equal to 1 Hpa.

[0036] Optionally, the preset protective film parameters include protective film thickness, bonding temperature, bonding time, and bonding pressure.

[0037] Optionally, the thickness of the protective film ranges from 30 to 60 μm; and / or, the bonding temperature ranges from 150 to 200°C; and / or, the bonding time ranges from 90 to 120 s; and / or, the bonding pressure ranges from 90 to 120 kg / cm². 2 .

[0038] In addition, the present invention also provides a single-sided flexible circuit board, which is manufactured using the aforementioned manufacturing method.

[0039] The beneficial effects of this invention are as follows: Using the provided double-sided roll material as a substrate for manufacturing single-sided roll material can, to some extent, avoid the shortcomings of traditional single-sided roll material substrates being too thin. Utilizing the thickness of the double-sided roll material reduces wrinkles and abnormal expansion / contraction. For the provided double-sided roll material, both sides are first exposed and developed, so that the first side forms a circuit exposure pattern while the second side is not exposed. This facilitates the subsequent etching process, allowing the first side to be used to create a circuit layer, forming a semi-finished roll material circuit board with single-sided circuitry, which is convenient for subsequent single-sided roll material fabrication. During the exposure and development of the double-sided roll material and the etching of the double-sided roll material, the presence of three layers of material support (including two conductive layers and an insulating layer between the two conductive layers) effectively reduces the impact of... The thinner thickness leads to problems with wrinkles and abnormal expansion / contraction. After the double-sided board to be etched is completed, a protective film is applied to its first side (i.e., the side with the circuitry). After the protective film is applied, the subsequent single-sheet cutting and etching process is carried out. Due to the support of the protective film, it can provide support and protection for the single-sided circuitry, further preventing wrinkles and abnormal expansion / contraction. After being cut into single double-sided boards, both sides of each single double-sided board are exposed and developed, so that the protective film on the first side of the single double-sided board is not exposed, while the second side is exposed. This ensures that during subsequent etching, the protective film on the first side and its inner circuitry are not etched away, while the exposed conductive layer on the second side is etched away, thus forming batches of single-sided flexible circuit boards that meet the requirements.

[0040] The single-sided flexible circuit board and its manufacturing method of the present invention, based on the thickness support of the double-sided roll before etching and the support of the protective film on the single-sided circuit after etching, can effectively avoid the problems of wrinkles and abnormal expansion and contraction generated in the traditional roll single-sided process, and can effectively improve the yield and quality of single-sided products. Attached Figure Description

[0041] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0042] Figure 1 A flowchart of a method for manufacturing a single-sided flexible circuit board according to Embodiment 1 of the present invention is shown;

[0043] Figure 2 This shows a cross-sectional view of the double-sided sheet roll in Embodiment 1 of the present invention;

[0044] Figure 3 This shows a cross-sectional view of the double-sided roll of material covered with a first negative photosensitive dry film in Embodiment 1 of the present invention.

[0045] Figure 4 A cross-sectional view of the semi-finished coil circuit board in Embodiment 1 of the present invention is shown.

[0046] Figure 5 This shows a cross-sectional view of the semi-finished roll circuit board after the protective film has been applied in Embodiment 1 of the present invention;

[0047] Figure 6 This shows a cross-sectional view of the structure of a single double-sided panel after a second negative photosensitive dry film is laminated to both sides in Embodiment 1 of the present invention.

[0048] Figure 7 This shows a cross-sectional view of a semi-finished single-sided panel formed after exposure and development in Embodiment 1 of the present invention.

[0049] Figure 8 A cross-sectional view of the single-sided flexible circuit board formed in Embodiment 1 of the present invention is shown.

[0050] The labels in the attached figures are explained as follows:

[0051] 1. Conductive layer, 2. Insulating layer, 3. First negative photosensitive dry film, 4. Circuit layer, 5. Protective film, 6. Protective film window, 7. Second negative photosensitive dry film. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] This embodiment provides a method for manufacturing a single-sided flexible circuit board, such as... Figure 1 As shown, it includes:

[0055] S1: Provides double-sided roll stock;

[0056] S2: Expose and develop both sides of the roll double-sided panel to form a circuit exposure pattern on the first side of the roll double-sided panel and prevent the second side of the roll double-sided panel from being exposed, thus obtaining the double-sided panel to be etched.

[0057] S3: Etch both sides of the double-sided board to be etched to obtain a semi-finished roll circuit board;

[0058] S4: Apply a protective film to the first side of the semi-finished roll circuit board according to the preset protective film parameters, and cut the semi-finished roll circuit board with the protective film applied into multiple single double-sided boards.

[0059] S5: Expose and develop both sides of each single double-sided board so that the protective film on the first side of each single circuit board is not exposed, and the second side of each single circuit board is exposed, to obtain a semi-finished single board corresponding to each single double-sided board.

[0060] S6: Etch both sides of each of the semi-finished single-sided boards to obtain multiple single-sided flexible circuit boards.

[0061] In this embodiment, the provided roll double-sided board is used as the roll substrate to manufacture the roll single-sided board, which can avoid the defects of the traditional roll single-sided substrate being too thin to a certain extent. The thickness of the double-sided board reduces wrinkles and abnormal expansion and contraction. For the provided roll double-sided board, both sides are first exposed and developed, so that the first side forms a circuit exposure pattern while the second side is not exposed. This facilitates the subsequent etching process, allowing the first side to be used to create a circuit layer, forming a semi-finished roll circuit board with single-sided circuitry, which is convenient for subsequent single-sided board fabrication. During the exposure and development of the roll double-sided board and the etching of the double-sided board to be etched, the presence of three layers of material (including two conductive layers and an insulating layer between the two conductive layers) effectively reduces the thickness-related defects. To address the issues of wrinkles and abnormal expansion / contraction caused by thinner thicknesses, a protective film is applied to the first side (the side with the circuitry) of the double-sided board after etching. Following this, subsequent single-sheet cutting and etching processes are performed. The protective film provides support and protection for the single-sided circuitry, further preventing wrinkles and abnormal expansion / contraction. After cutting into single double-sided boards, both sides of each board are exposed and developed. This ensures that the protective film on the first side is not exposed, while the second side is. This guarantees that during subsequent etching, the protective film and its inner circuitry on the first side are not etched away, while the exposed conductive layer on the second side is etched away, resulting in the batch production of single-sided flexible circuit boards that meet the requirements.

[0062] The method for manufacturing a single-sided flexible circuit board in this embodiment, based on the thickness support of the double-sided roll sheet before etching and the support of the protective film on the single-sided circuit after etching, can effectively avoid problems such as wrinkles and abnormal expansion and contraction caused by traditional roll single-sided sheet processes, and can effectively improve the yield and quality of single-sided sheet products.

[0063] The following provides a detailed description of each step of the manufacturing method in this embodiment.

[0064] In this embodiment S1, the double-sided sheet of the roll is cut, and its cross-sectional structure is as follows: Figure 2 As shown, in Figure 2 In the diagram, 1 represents the conductive layers on both sides of the double-sided sheet of the roll material, and 2 represents the insulating layer between the two conductive layers 1.

[0065] Following S1, the method also includes:

[0066] Chemical cleaning is performed on the double-sided sheet metal roll.

[0067] Chemical cleaning can remove organic matter and other foreign matter from the conductive layer, increasing its roughness and helping to improve the adhesion between the subsequent negative photosensitive dry film and the conductive layer.

[0068] Preferably, embodiment S2 includes:

[0069] S21: Using a hot roller pressing method, a first negative photosensitive dry film is applied to both sides of the double-sided sheet of the roll material.

[0070] S22: Provide a first transparent film without a circuit pattern and an exposed film with a circuit pattern, respectively;

[0071] S23: The first side of the roll double-sided panel is exposed and developed using the exposure film, so that the first negative photosensitive dry film on the first side of the roll double-sided panel is partially dissolved to form the exposed circuit pattern.

[0072] S24: The second side of the roll double-sided panel is exposed and developed using the first transparent film, so that the first negative photosensitive dry film on the second side of the roll double-sided panel is not dissolved, so that the second side of the roll double-sided panel is not exposed, and the double-sided panel to be etched is obtained.

[0073] Hot roll lamination is typically achieved using a hot roll laminating machine. This machine usually employs a cylinder to control the lifting and lowering of the rollers, ensuring uniform pressure on both sides of the rollers. This allows the dry film to adhere evenly to the board, improving lamination quality. Furthermore, the hot roll laminating machine utilizes an inside-out heating method, which helps ensure uniform heating of the dry film during the lamination process, enhancing the lamination effect. The provided exposure film is used for exposing the circuitry on the circuitry side (i.e., the first side) of the roll double-sided PCB. It features circuitry patterns, typically created from circuit design drawings through photolithography or printing. Therefore, using the provided exposure film to expose and develop the circuitry on the first side of the roll double-sided PCB allows the first negative photosensitive dry film to partially dissolve according to the pattern on the exposure film, forming a circuitry exposure pattern that meets design requirements. This facilitates the exposure of the conductive layer (i.e., the area of ​​the conductive layer to be etched away later) on the first side, allowing the desired circuitry layer to be formed through etching. The first transparent film provided has no circuit pattern. The first negative photosensitive dry film provided in this embodiment becomes difficult to be removed by the developer after exposure. Therefore, by using the first transparent film to perform air exposure and development on the second side (i.e. non-circuit side) of the roll double-sided board, the light during exposure can pass through the first transparent film without obstruction, so that the first negative photosensitive dry film is not dissolved, and the conductive layer inside is completely covered and not exposed, so that the conductive layer can be completely retained after subsequent etching.

[0074] In this embodiment S21, the cross-sectional structure of the roll double-sided panel covered with the first negative photosensitive dry film is as follows: Figure 3 As shown, in Figure 3 In the middle, 3 is the first negative photosensitive dry film.

[0075] Preferably, embodiment S3 includes:

[0076] S31: Based on the circuit exposure pattern, the first side of the double-sided board to be etched is etched, so that the conductive layer on the first side of the circuit board to be etched forms a circuit layer.

[0077] S32: Etch the second side of the double-sided board to be etched, so that the conductive layer on the second side of the circuit board to be etched is completely preserved;

[0078] S33: Remove the first negative photosensitive dry film from both sides of the etched double-sided board to obtain the semi-finished roll circuit board with single-sided circuitry.

[0079] After both sides of the roll-to-roll double-sided board have been exposed and developed to form the double-sided board to be etched, the first side (i.e., the circuit side) is etched based on the formed circuit exposure pattern to form the required circuit layer. The second side (non-circuit side) is completely retained due to the masking effect of the first negative photosensitive dry film. Finally, the remaining first negative photosensitive dry film on both sides (including the remaining first negative photosensitive dry film on the first side and the completely retained first negative photosensitive dry film on the second side) is removed to form a semi-finished roll-to-roll double-sided board with single-sided circuitry that meets the circuit design requirements. In the above exposure, development, and etching process, on the one hand, since the entire roll-to-roll flexible substrate is a double-sided board, wrinkles and abnormal expansion and contraction are less likely to occur due to the thickness characteristics of double-sided boards; on the other hand, circuitry can be formed on one side of the double-sided board as needed, facilitating the subsequent fabrication of a single-sided flexible circuit board.

[0080] In this embodiment, after the double-sided roll of circuit board has undergone exposure, development, and etching on both sides, the cross-sectional structure of the resulting semi-finished roll circuit board is as follows: Figure 4 As shown, in Figure 4 In the diagram, 4 represents the circuit layer formed on the conductive layer 1 of the first side (specifically the upper side).

[0081] In this embodiment S4, the preset protective film parameters include protective film thickness, bonding temperature, bonding time, and bonding pressure.

[0082] Specifically, the protective film thickness ranges from 30 to 60 μm; and / or, the bonding temperature ranges from 150 to 200°C; and / or, the bonding time ranges from 90 to 120 seconds; and / or, the bonding pressure ranges from 90 to 120 kg / cm². 2 .

[0083] By controlling the bonding temperature, bonding time, and bonding pressure, a protective film with a thickness ranging from 30 to 60 μm can be formed. This specific thickness of protective film ensures that it not only prevents product oxidation and scratches but also provides good support for subsequent exposure, development, and etching of single-sided and double-sided boards. This achieves anti-wrinkle and anti-swelling abnormalities throughout the entire process, improving the yield and quality of the formed single-sided flexible circuit board.

[0084] In this embodiment S4, the protective film has been pre-windowed to facilitate subsequent solder mask application. The cross-sectional structure of the semi-finished coil circuit board after applying the protective film is as follows. Figure 5 As shown, in Figure 5 In the middle, 5 represents the protective film, and 6 represents the window opening of the protective film.

[0085] In S4, the semi-finished roll circuit board with protective film is cut into individual sheets, so that each sheet can be used for subsequent processes. In the single-sheet process, the flexible board does not need to bear the tension of winding and unwinding, which can further reduce the risk of product expansion and contraction and wrinkling.

[0086] Preferably, embodiment S5 includes:

[0087] S51: Using a vacuum lamination method, according to preset lamination film parameters, a second negative photosensitive dry film is laminated onto both sides of each single double-sided panel.

[0088] S52: Provides a second transparent film without a line pattern and a pure black film respectively;

[0089] S53: The second transparent film is used to expose and develop the first side of each single double-sided panel, so that the second negative photosensitive dry film on the first side of each single double-sided panel is completely not dissolved, so that the protective film on the first side of each single double-sided panel is not exposed.

[0090] S54: Using the pure black film, the second side of each single double-sided panel is exposed and developed, so that the second negative photosensitive dry film on the second side of each single double-sided panel is completely dissolved, so that the conductive layer on the second side of each single double-sided panel is completely exposed, thereby obtaining the semi-finished single panel corresponding to each single double-sided panel.

[0091] Because of the windows in the protective film on each single-sided double-sided board, the surface difference is relatively large. Vacuum lamination can avoid uneven application of the dry film caused by these large differences, resulting in a more uniform bonding of the second negative photosensitive dry film. This facilitates subsequent exposure, development, and etching of each single-sided double-sided board. Similar to the aforementioned first transparent film, using the provided second transparent film without circuit patterns, the first side (i.e., the circuit side, the side with the protective film) of each single-sided double-sided board is air-exposed and developed. This allows light to pass through the second transparent film without obstruction, preventing the second negative photosensitive dry film from dissolving and completely covering the inner protective film. This ensures that the protective film is fully preserved after etching. The pure black film is completely different from the second transparent film. It has strong light absorption properties, so that light cannot pass through it during the exposure process (that is, the entire area covered by the pure black film is an unexposed area). Using this pure black film to perform air exposure and development on the second side (i.e., the non-circuit side, which is made of conductive layer) of a single double-sided board, the entire second negative photosensitive dry film on the second side can be an unexposed area. Based on the characteristics of the second negative photosensitive dry film, its unexposed area will react with the developer and be dissolved, so that the conductive layer on the second side of each single double-sided board can be completely exposed, which is convenient for subsequent etching to be completely removed, thereby forming the required single-sided flexible circuit board with only single-sided circuitry.

[0092] In this embodiment S51, the preset dry film parameters include the second negative photosensitive dry film thickness, vacuuming time, first vacuum degree, pressing time, and second vacuum degree; wherein, the first vacuum degree refers to the vacuum degree during the vacuuming process when vacuum pressing film, and the second vacuum degree refers to the vacuum degree during the pressing process when vacuum pressing film.

[0093] Specifically, the thickness of the second negative photosensitive dry film ranges from 25 to 55 μm; and / or, the vacuuming time ranges from 5 to 20 s; and / or, the first vacuum degree is less than or equal to 20 Hpa; and / or, the pressing time ranges from 5 to 15 s; and / or, the second vacuum degree is less than or equal to 1 Hpa.

[0094] The above parameters can effectively overcome the height difference caused by the opening of the protective film, forming a second negative photosensitive dry film thickness in the range of 25-55μm. The second negative photosensitive dry film thickness of the above specific thickness can not only provide better support for the subsequent single-sheet process, but also ensure that the two sides of each single double-sided panel achieve the required exposure and development effect.

[0095] In this embodiment, after single-sheet cutting, the cross-sectional structure after the second negative photosensitive dry film is laminated to both sides of the single double-sided panel is as follows: Figure 6 As shown, the cross-sectional structure of a semi-finished single-sided panel formed after exposure and development on both sides of a single double-sided panel is as follows. Figure 7 As shown, in Figure 6 and Figure 7 In the middle, 7 represents the second negative photosensitive dry film.

[0096] Preferably, embodiment S6 includes:

[0097] S61: The first side of each of the semi-finished single panels is etched so that the protective film on the first side of each of the semi-finished single panels is retained.

[0098] S62: The second side of each of the semi-finished single panels is etched so that the conductive layer on the second side of each of the semi-finished single panels is etched away.

[0099] S63: Remove the second negative photosensitive dry film from the first side of each semi-finished single-sided board after etching to obtain a plurality of the single-sided flexible circuit boards.

[0100] After both sides of a single double-sided board are exposed and developed to form a semi-finished single-sided board, the first side (i.e., the circuit side, the side with the protective film) is etched, and is completely preserved due to the covering of the outer second negative photosensitive dry film. The second side (i.e., the non-circuit side, made of conductive layer) is etched, and since the conductive layer on this side is completely exposed, it is also completely etched away. Finally, the second negative photosensitive dry film on the first side is removed, thus forming a single-sided flexible circuit board with only single-sided circuitry. During the above etching process, the presence of the protective film and the second negative photosensitive dry film effectively prevents product wrinkling and abnormal expansion and contraction caused by excessively thin products.

[0101] The cross-sectional structure of the single-sided flexible circuit board formed in this embodiment is as follows: Figure 8 As shown.

[0102] Example 2

[0103] This embodiment provides a single-sided flexible circuit board, which is manufactured using the single-sided flexible circuit board manufacturing method described in Embodiment 1.

[0104] This embodiment, based on the thickness support of the roll double-sided board before etching and the support of the protective film on the single-sided circuit after etching, can effectively avoid the problems of wrinkles and abnormal expansion and contraction generated in the traditional roll single-sided board process, and can effectively improve the yield and quality of single-sided board products.

[0105] The manufacturing method of the single-sided flexible circuit board in this embodiment is the same as the method described in Embodiment 1. Therefore, for details not covered in this embodiment, please refer to Embodiment 1 and... Figures 1 to 7 The specific description will not be repeated in this embodiment.

[0106] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for manufacturing a single-sided flexible circuit board, characterized in that, The method includes: Double-sided rolls are available; Both sides of the roll double-sided panel are exposed and developed to form a circuit exposure pattern on the first side of the roll double-sided panel, while the second side of the roll double-sided panel is not exposed, thus obtaining the double-sided panel to be etched. Etching is performed on both sides of the double-sided board to be etched to obtain a semi-finished roll circuit board. According to the preset protective film application parameters, a protective film is applied to the first side of the semi-finished roll circuit board, and the semi-finished roll circuit board with the protective film applied is cut into single sheets to obtain multiple single double-sided boards. Both sides of each single double-sided panel are exposed and developed so that the protective film on the first side of each single double-sided panel is not exposed, and the second side of each single double-sided panel is exposed, to obtain a semi-finished single panel corresponding to each single double-sided panel. Both sides of each of the semi-finished single-sided boards are etched to obtain multiple single-sided flexible circuit boards.

2. The manufacturing method according to claim 1, characterized in that, The process of exposing and developing both sides of the roll double-sided panel to form a circuit exposure pattern on the first side of the roll double-sided panel, while ensuring that the second side of the roll double-sided panel is not exposed, to obtain the double-sided panel to be etched, includes: A first negative photosensitive dry film is applied to both sides of the double-sided sheet of the roll material using a hot roller pressing method. A first transparent film without a circuit pattern and an exposed film with a circuit pattern are provided respectively; The first side of the roll double-sided panel is exposed and developed using the exposure film, so that the first negative photosensitive dry film on the first side of the roll double-sided panel is partially dissolved to form the exposed circuit pattern. The second side of the roll double-sided panel is exposed and developed using the first transparent film, so that the first negative photosensitive dry film on the second side of the roll double-sided panel is not dissolved, so that the second side of the roll double-sided panel is not exposed, thus obtaining the double-sided panel to be etched.

3. The manufacturing method according to claim 2, characterized in that, Both sides of the double-sided sheet of the roll material are conductive layers; The etching process involves etching both sides of the double-sided panel to obtain a semi-finished roll circuit board, including: Based on the circuit exposure pattern, the first side of the double-sided board to be etched is etched, so that the conductive layer on the first side of the circuit board to be etched forms a circuit layer. The second side of the double-sided board to be etched is etched so that the conductive layer on the second side of the circuit board to be etched is completely preserved. Remove the first negative photosensitive dry film from both sides of the etched double-sided board to obtain the semi-finished roll circuit board with single-sided circuitry.

4. The manufacturing method according to claim 1, characterized in that, Both sides of the double-sided sheet of the roll material are conductive layers; The step of exposing and developing both sides of each of the single double-sided boards, so that the protective film on the first side of each single circuit board is not exposed, and the second side of each single circuit board is exposed, includes: Using a vacuum lamination method, a second negative photosensitive dry film is laminated onto both sides of each single double-sided panel according to preset lamination parameters; A second transparent film without a line pattern and a pure black film are provided respectively; The second transparent film is used to expose and develop the first side of each single double-sided panel, so that the second negative photosensitive dry film on the first side of each single double-sided panel is completely not dissolved, so that the protective film on the first side of each single double-sided panel is not exposed. The second side of each single double-sided panel is exposed and developed using the pure black film, so that the second negative photosensitive dry film on the second side of each single double-sided panel is completely dissolved, thereby exposing the conductive layer on the second side of each single double-sided panel, to obtain the semi-finished single panel corresponding to each single double-sided panel.

5. The manufacturing method according to claim 4, characterized in that, The process involves etching both sides of each semi-finished single-sided panel to obtain multiple single-sided flexible circuit boards, including: The first side of each of the semi-finished single panels is etched so that the protective film on the first side of each of the semi-finished single panels is retained. The second side of each of the semi-finished single-sided panels is etched so that the conductive layer on the second side of each of the semi-finished single-sided panels is etched away. The second negative photosensitive dry film on the first side of each semi-finished single-sided board after etching is removed to obtain a plurality of the single-sided flexible circuit boards.

6. The manufacturing method according to claim 4, characterized in that, The preset dry film parameters include the thickness of the second negative photosensitive dry film, the vacuuming time, the first vacuum degree, the pressing time, and the second vacuum degree; wherein, the first vacuum degree refers to the vacuum degree during the vacuuming process when vacuum pressing film is produced, and the second vacuum degree refers to the vacuum degree during the pressing process when vacuum pressing film is produced.

7. The manufacturing method according to claim 6, characterized in that, The thickness of the second negative photosensitive dry film ranges from 25 to 55 μm; and / or, the vacuuming time ranges from 5 to 20 s; and / or, the first vacuum degree is less than or equal to 20 Hpa; and / or, the pressing time ranges from 5 to 15 s; and / or, the second vacuum degree is less than or equal to 1 Hpa.

8. The manufacturing method according to claim 1, characterized in that, The preset protective film parameters include protective film thickness, bonding temperature, bonding time, and bonding pressure.

9. The manufacturing method according to claim 8, characterized in that, The protective film thickness ranges from 30 to 60 μm; and / or, the bonding temperature ranges from 150 to 200 °C; and / or, the bonding time ranges from 90 to 120 s; and / or, the bonding pressure ranges from 90 to 120 kg / cm². 2 .

10. A single-sided flexible circuit board, characterized in that, It is manufactured using the manufacturing method described in any one of claims 1 to 9.

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