A fast FPC production process with a fully dry process

Abstract

The present invention discloses a fast FPC production process with a full dry process, including: using laser to make circuits on an unwound flexible substrate to generate a circuit board; performing AOI testing on the circuit board, and applying a cover film to the tested circuit board; using laser to perform windowing on the circuit board after applying the cover film; performing nickel-gold and reinforcing plate-applying operations on the circuit board after the windowing treatment; and testing the circuit board with the reinforcing plate attached; performing laser drilling and shape cutting on the tested circuit board to generate a finished FPC product; and performing FQC testing on the finished FPC product and packaging. Through the above technical scheme, the present invention provides a new FPC manufacturing method, which can realize the fully automatic production of FPC, and completely eliminates wastewater discharge, avoiding the pollution of the environment by chemical methods.

Description

Technical Field

[0001] The invention relates to the technical field of FPC production, and in particular to a fast FPC production process of a full dry process. Background Art

[0002] Flexible Printed Circuit (FPC) is a kind of flexible printed circuit board with high reliability and high insulation made of polyimide or polyester film as the substrate. It has the characteristics of high wiring density, light weight, thin thickness and good bendability. The general FPC process in the prior art is as follows: unwinding-drilling-black hole-copper plating-dry film-exposure-development-etching-stripping-AOI-covering film-nickel gold-screen solder mask-sticking reinforcement board-molding 1-testing-molding 2-FQC-packaging. However, in the above process, for FPC production, its production process is more and more complicated, which cannot meet the requirements of FPC rapid production. At the same time, in the above existing process, etching is generally carried out by chemical methods. The chemical reagents used in the etching process are easy to cause certain pollution to the environment, which is not conducive to environmental protection requirements. It is necessary to invest heavily in the construction of wastewater treatment equipment and the operating costs are high. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a fast FPC production process with a full dry process, which can save traditional process links and reduce environmental impact and investment capital.

[0004] In order to achieve the above technical objectives, the present invention provides the following technical solutions:

[0005] A fast FPC production process with a full dry process, comprising:

[0006] The circuit is made on the unwound flexible substrate by laser to generate a circuit board; the circuit board is subjected to AOI test, and the tested circuit board is covered with a cover film; the circuit board after the cover film is treated with a laser for windowing; the circuit board after the windowing is nickel-gold and reinforced with a reinforcing plate; and the circuit board with the reinforced plate is tested; the tested circuit board is subjected to laser drilling and shape cutting to generate a finished FPC product; the finished FPC product is subjected to FQC test and packaged.

[0007] Optionally, the circuit production process includes: laser etching the copper foil layer of the flexible substrate by laser equipment, during the etching process, etching a spacing area on the flexible substrate by laser, wherein the spacing area is used to separate the FPC circuit copper foil and the waste copper foil, and the waste copper foil in the spacing area is removed by laser to generate a circuit board.

[0008] Optionally, the window opening operation process includes: obtaining a first image of the circuit board after the covering film is affixed through a camera, analyzing the first image based on machine vision, obtaining a window opening position, generating a control signal based on the window opening position, and performing window opening processing on the flexible substrate through a laser device.

[0009] Optionally, the laser drilling and contour cutting process includes:

[0010] A second image of the tested circuit board is obtained by a camera, and a sample image is obtained and matched with the second image. The window opening and shape cutting positions are obtained based on the matching results, and the window opening and shape cutting positions are mapped to the circuit board. The window opening and shape cutting positions are processed by laser to generate a finished FPC product.

[0011] Optionally, during the AOI test process, the circuit board is fixed. After fixation, the circuit board is scanned by a camera to obtain a third image of the circuit board. Based on the third image, defects are identified on the third image to obtain a defect identification result. Based on the defect identification result, it is determined whether the AOI test is qualified.

[0012] Optionally, the strong plate in the patch strong plate includes a metal strong plate, a PI strong plate and a glass fiber strong plate.

[0013] Optionally, during the FQC testing process, the appearance image of the FPC finished product is scanned, and the appearance image is recognized by a deep learning model to generate an appearance inspection result, and a performance test is performed on the FPC finished product based on the appearance inspection result, and the FPC finished product is packaged based on the performance inspection result.

[0014] Optionally, the flexible substrate is a PI material substrate covered with copper foil.

[0015] The present invention has the following technical effects:

[0016] The present invention is a brand-new FPC manufacturing method. Compared with the traditional chemical etching method which can only rely on manual production, the present invention can realize the fully automatic production of FPC, and completely eliminates wastewater discharge, thus avoiding the pollution of the environment caused by chemical methods.

[0017] The present invention adopts a new process, which not only saves the traditional process links, but also greatly reduces the equipment investment of related processes. At the same time, there is no environmental pressure of chemical etching, and the investment of punching molds for molding is also eliminated, eliminating huge noise pollution. Basically, the entire FPC can be manufactured by a laser device. It is particularly suitable for making single-sided FPC boards, especially for CCS of new energy batteries, car antennas, mobile phone antennas, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A schematic diagram of a process flow provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of circuit manufacturing provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of waste removal molding provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a cover film after being attached according to an embodiment of the present invention;

[0023] Figure 5 A schematic diagram of a window after opening provided by an embodiment of the present invention;

[0024] Figure 6 A schematic diagram after cutting and forming provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In order to solve the problems existing in the prior art, the present invention provides the following solutions:

[0027] like Figure 1 The present invention provides a fast FPC production process with a full dry process, and the specific production process is as follows: unwinding - laser 1 (circuit production) - AOI - cover film - laser 2 (window opening) - nickel gold - reinforcing plate - test - laser 3 (drilling, shape cutting) - FQC - packaging. The present invention is specifically described through the following steps:

[0028] Unwinding: The coil is unwound by the FPC unwinding machine, and the rolled non-glue substrate, i.e., the flexible substrate, is unwound. During the unwinding process, the non-glue substrate is flattened, and the subsequent operations are performed on the flexible substrate after unwinding. The non-glue substrate used in the present invention consists of only two parts, copper foil and PI. The PI material is covered with copper foil, and has the advantages of being thinner, having better dimensional stability, higher heat resistance, higher bending resistance, and better chemical resistance than the glue substrate.

[0029] Laser circuit production: extract the circuit sample image in the computer. After extraction, align the sample image with the area where the circuit needs to be made to generate a circuit path. Based on the circuit path, use the laser to cut the copper foil layer of the flexible substrate along the edge of the circuit path, but do not cut through the PI film under the copper foil. After cutting, remove the excess copper foil outside the circuit. In the above process, calculate and control the laser equipment to laser etch the flexible substrate. When etching, the edge of the circuit is etched as a spacing area. The spacing area is used to separate the FPC circuit copper foil and the waste copper foil, such as Figure 2 As shown, one part is the FPC circuit copper foil that needs to be retained, and the other part is the redundant waste copper foil. After etching the spacing area on the substrate, the area to be removed is set by computer. The waste copper foil in the area to be removed is the copper foil in the spacing area and the remaining copper foil on the spacing area. By removing the copper foil except the circuit, the PI film below the copper foil is not etched. The wavelength of the laser is 355nm, the pulse width is 1-12ps, the output average power is 0-20W, the repetition frequency is 30-800kHz, and the defocus amount is -3-3mm. After etching is completed by the above laser, as shown in FIG. Figure 3 As shown, a substrate with circuits, i.e. a circuit board, is generated.

[0030] AOI, in the process of AOI optical automated inspection, the circuit board is fixed, and after fixation, the circuit board is scanned by a camera to obtain an image of the circuit board, i.e., a third image, and the above-mentioned circuit board image is subjected to defect recognition by a machine vision method. The machine vision method in the present invention recognizes the circuit board image by a deep learning model, wherein the deep learning model includes four convolution modules, two fully connected layers, and an output layer, and the output includes the circuit board image with marked defects and the defect category, which is constructed by a python component. After the construction is completed, the network parameters of the above-mentioned model are initialized, and the circuit board image is collected to train the model. During the training process, the defects in the circuit board image are marked as defects and set as negative samples, and the same number of positive samples are set to train the model. After the training is completed, the circuit board image is recognized, and a defect recognition result is generated. The circuit board image and the defect category in the defect recognition result are counted. When a defect occurs, it is judged that the defective circuit board is unqualified in the AOI test, and the relevant professionals are reminded to conduct inspection and review.

[0031] Paste the covering film. Paste the covering film on the formed copper foil. During the pasting process, the covering film uses a combination of PI and glue, such as Figure 4 As shown, the circuit board after the cover film is generated.

[0032] Laser 2 opens a window, etches off the covering film on the pad to expose the via. In this process, a camera is used to capture the image of the circuit board after the previous step, i.e., the first image, and the first image is analyzed and processed using machine vision. In this process, a window opening sample image is obtained, and feature matching is performed between the window opening sample image and the captured image to match the same circuit features. After the matching is completed, the window opening position in the sample image is mapped to the captured image, and the position is marked. After marking, a control signal for the relevant position is generated, and the control signal controls the laser device to perform window opening processing on the above position, such as Figure 5 As shown, the circuit board after windowing is generated.

[0033] Nickel-gold, through chemical reaction, replaces palladium on the surface of copper, and then plates a layer of nickel-phosphorus alloy on the basis of the palladium core, and then plates a layer of gold on the surface of nickel through replacement reaction. The surface treatment of circuit boards is used to prevent the copper on the surface of circuit boards from being oxidized or corroded. It is also used for welding and contact.

[0034] The reinforcing board is pasted. In this process, the reinforcing board includes metal reinforcing board, PI reinforcing board and glass fiber reinforcing board. The reinforcing board is pasted to the circuit board to improve the strength of the flexible substrate.

[0035] Test, perform peel strength test on the circuit board after attaching the reinforcement board.

[0036] Laser 3 drilling and shape cutting, forming, use a camera to capture the image of the circuit board after the test, that is, the second image, and obtain the drilling and shape cutting sample image, in which the segmentation area of ​​the circuit board is set, and the sample image is feature matched with the image of the circuit board. After the matching is completed, the drilling and segmentation areas in the sample image are mapped to the image of the circuit board, and the drilling position size and segmentation area edge line mapped in the circuit board image are extracted, and a related control signal is generated, and the signal is transmitted to the laser device to control the laser device to segment at the location of the drilling position size and the segmentation area edge line, such as Figure 6 As shown, the FPC finished product is generated.

[0037] FQC, FQC test is performed on the FPC finished product. In the above process, the appearance of the FPC finished product is first inspected, and the appearance image of the FPC finished product is captured by camera scanning, and the appearance image is recognized by the deep learning model. The content is recognized by the convolutional neural network, including five convolutional layers, two fully connected layers and one output layer. The above model is constructed by the python component. After the construction is completed, negative samples and positive samples are collected to train the above model. The ratio of negative samples to positive samples is 3:7. The defects are marked in the negative samples and the defect categories are pointed out. The appearance image is recognized by the trained model to identify different defects. After the defect recognition is completed, the performance test of the cut circuit board is carried out. After the performance test is completed, it is packaged.

[0038] Packaging: Packing the FQC-completed circuit boards to generate FPC products.

[0039] The present invention adopts a new process, which not only saves the traditional process links, but also greatly reduces the equipment investment of related processes. At the same time, there is no environmental pressure of chemical etching, and the investment of punching molds for molding is also eliminated, eliminating huge noise pollution. Basically, the entire FPC can be manufactured by a laser device. It is particularly suitable for making single-sided FPC boards, especially for CCS of new energy batteries, car antennas, mobile phone antennas, etc.

[0040] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A fast FPC production process with a full dry process, characterized in that: include: The circuit is made on the unwound flexible substrate by laser to generate a circuit board; Carry out AOI test on the circuit board and perform covering film operation on the tested circuit board; The circuit board after the cover film is pasted is opened by laser; the circuit board after the window opening is nickel-gold and reinforced with a reinforcing plate is applied; the circuit board with the reinforced plate is tested; the circuit board after the test is laser drilled and cut to produce a finished FPC product; Conduct FQC test on FPC finished products and package them; The laser drilling and contour cutting process includes: Acquire a second image of the tested circuit board through a camera, acquire a sample image and match the second image with the sample image, acquire drilling and contour cutting positions based on the matching result, map the drilling and contour cutting positions to the image of the circuit board, segment the drilling and contour cutting positions through a laser, and generate a finished FPC product; Specifically, laser drilling and shape cutting, forming, using a camera to capture the image of the circuit board after the test, that is, the second image, and obtain a drilling and shape cutting sample image, in which a segmentation area of ​​the circuit board is set, and feature matching is performed between the sample image and the image of the circuit board. After the matching is completed, the drilling and segmentation areas in the sample image are mapped to the image of the circuit board, and the drilling position size and segmentation area edge line mapped in the circuit board image are extracted, and a related control signal is generated, and the signal is transmitted to the laser device to control the laser device to segment at the drilling position size and the location of the segmentation area edge line to generate a FPC finished product; During the AOI test, the circuit board is fixed, and after fixation, the circuit board is scanned by a camera to obtain a third image of the circuit board, and defects are identified on the third image according to the third image to obtain a defect identification result, and whether the AOI test is qualified is determined according to the defect identification result; Specifically, during the AOI optical automated inspection process, the circuit board is fixed, and after fixation, the circuit board is scanned by a camera to obtain an image of the circuit board, i.e., a third image, and defects are identified on the above-mentioned circuit board image by a machine vision method. The machine vision method identifies the circuit board image by a deep learning model, wherein the deep learning model includes four convolution modules, two fully connected layers, and an output layer, and the output includes a circuit board image with defects marked and a defect category. The model is constructed by a python component, and after the construction is completed, the network parameters of the above-mentioned model are initialized, and the circuit board image is collected to train the model. During the training process, the defects in the circuit board image are marked as defects and set as negative samples, and the same number of positive samples are set to train the model. After the training is completed, the circuit board image is identified to generate a defect identification result, and the circuit board image and the defect category in the defect identification result are counted. When a defect occurs, it is judged that the defective circuit board is unqualified in the AOI test, and the relevant professionals are reminded to conduct inspection and review.

2. The fast FPC production process of the all-dry process according to claim 1, characterized in that: The process of circuit production includes: laser etching the copper foil layer of the flexible substrate by laser equipment. During the etching process, the spacing area is etched on the flexible substrate by laser, wherein the spacing area is used to separate the FPC circuit copper foil and the waste copper foil. The waste copper foil in the spacing area is removed by laser to generate a circuit board.

3. The fast FPC production process of the all-dry process according to claim 1, characterized in that: The process of the window opening operation includes: obtaining a first image of the circuit board after the covering film is affixed through a camera, analyzing the first image based on machine vision, obtaining the window opening position, generating a control signal based on the window opening position, and performing window opening processing on the flexible substrate through a laser device.

4. The fast FPC production process of the all-dry process according to claim 1 is characterized in that: The reinforcing plates in the pasted reinforcing plates include metal reinforcing plates, PI reinforcing plates and glass fiber reinforcing plates.

5. The fast FPC production process of the all-dry process according to claim 1, characterized in that: During the FQC test process, the appearance image of the FPC finished product is scanned, and the appearance image is recognized by a deep learning model to generate an appearance inspection result, and the performance test of the FPC finished product is performed based on the appearance inspection result, and the FPC finished product is packaged based on the performance inspection result.

6. The fast FPC production process of the all-dry process according to claim 1, characterized in that: The flexible substrate is a PI material substrate covered with copper foil.

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