Flexible-rigid board with multi-layer flexible board and bending area ultra-fine line processing technology thereof

Abstract

The present application belongs to the technical field of printed wiring board, and particularly relates to a soft and hard combination board with multiple layers of soft board and a processing technology for ultra-fine lines in the bending area, which comprises the following steps: preparing multiple soft boards and respectively making lines and pasting cover films; preparing adhesive materials and opening windows; superimposing and pressing the soft boards and the adhesive materials; making drill holes and plating copper for the pressed multiple-layer board, then making ultra-fine lines in the bending area and pasting cover films; processing protection films in the bending area of the multiple-layer board; preparing semi-cured adhesive sheets and opening windows in the bending area, and superimposing and pressing the semi-cured adhesive sheets with the multiple-layer board; making drill holes, plating copper, lines, and removing the protection films; processing protection films in the bending area of the multiple-layer board; preparing semi-cured adhesive sheets and opening windows in the bending area, and superimposing and pressing the semi-cured adhesive sheets; making drill holes, plating copper, lines, and removing the protection films, and producing to finished products; the present application can not only reduce the height difference of the soft board, but also ensure the flatness of the board surface, and can process ultra-fine lines in the bending area of the soft board.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of printed wiring board, and particularly relates to a soft and hard combination board with multiple layers of soft board and a processing technology for super-fine lines in the bending area of the soft and hard combination board, in particular, the soft and hard combination board applied to dynamic bending consumer electronic products. BACKGROUND

[0002] With the continuous development of electronic technology, the market has higher and higher requirements for the performance and reliability of electronic products, and various electronic products are updated more and more frequently, which means that the performance is required to be higher and higher and the function is required to be more and more powerful. In order to meet these needs, the requirements for printed wiring boards are more stringent, and the soft and hard combination board has an irreplaceable advantage over rigid wiring boards, so more and more soft and hard combination boards are applied to electronic products. However, compared with rigid wiring boards, the soft and hard combination board has obvious difficulty in production process, such as super-fine lines in the bending area. SUMMARY

[0003] The present application aims to overcome the deficiencies in the prior art and provide a soft and hard combination board with multiple layers of soft board and a processing technology for super-fine lines in the bending area of the soft and hard combination board. The present application can effectively improve the bending frequency of the multiple layers of soft board and make super-fine lines in the bending area of the soft board, further improving the performance and meeting the multi-functional requirements of electronic products.

[0004] To achieve the above technical purposes, the technical solution adopted by the embodiments of the present application is as follows:

[0005] In a first aspect, the embodiments of the present application provide a processing technology for super-fine lines in the bending area of a soft and hard combination board with multiple layers of soft board, including the following steps:

[0006] Step S1, providing a first soft board of the soft and hard combination board, the first soft board comprising a first upper layer of copper foil and a first lower layer of copper foil, making a line pattern on the first upper layer of copper foil and the first lower layer of copper foil according to requirements and performing line quality inspection, and respectively adhering a first upper cover film and a first lower cover film to the upper and lower line surfaces;

[0007] Step S2, providing a second soft board of the soft and hard combination board, the second soft board comprising a second upper layer of copper foil, making a line pattern on the second upper layer of copper foil according to requirements and performing line quality inspection, and adhering a second cover film to the line surface;

[0008] Step S3, providing a third soft board of the soft and hard combination board, the third soft board comprising a third lower layer of copper foil, making a line pattern on the third lower layer of copper foil according to requirements and performing line quality inspection, and adhering a third cover film to the line surface;

[0009] Step S4, providing a fourth soft board of the soft and hard combination board, the fourth soft board comprising a fourth upper layer of copper foil;

[0010] Step S5, providing a fifth soft plate of the soft and hard combination plate, the fifth soft plate comprising a fifth lower copper foil;

[0011] Step S6, providing an adhesive material, windowing corresponding to the first finished product bending area position, and not doing anything corresponding to the second finished product bending area position;

[0012] Step S7, sequentially laminating and pressing the fifth soft plate, the adhesive material, the third soft plate, the adhesive material, the first soft plate, the adhesive material, the second soft plate, the adhesive material, and the fourth soft plate in a bottom-up order;

[0013] Step S8, after pressing, making a laser first blind hole, a first mechanical through hole, and copper plating according to the design data, and making a circuit on the fifth lower copper foil and the fourth upper copper foil, then pasting a fourth cover film on the circuit surface layer of the fourth soft plate, and pasting a fifth cover film on the circuit surface layer of the fifth soft plate;

[0014] Step S9, processing a first protective film on the first finished product bending area and the second finished product bending area of the fourth cover film and the fifth cover film;

[0015] Step S10, preparing a first prepreg, and windowing corresponding to the first finished product bending area position and the second finished product bending area position respectively;

[0016] Step S11, preparing a first copper foil;

[0017] Step S12, sequentially laminating and pressing the first copper foil, the first prepreg, the multilayer soft plate processed with the first protective film in step S9, the first prepreg, and the first copper foil in a bottom-up order;

[0018] Step S13, after pressing, making a laser second blind hole and copper plating according to the design data, and making a circuit on the first copper foil on the upper and lower surface layers, and then removing the first protective film;

[0019] Step S14, processing a second protective film on the first finished product bending area and the second finished product bending area of the fourth cover film and the fifth cover film;

[0020] Step S15, preparing a second prepreg, and windowing corresponding to the first finished product bending area position and the second finished product bending area position respectively;

[0021] Step S16, preparing a second copper foil;

[0022] Step S17, sequentially laminating and pressing the second copper foil, the second prepreg, the multilayer plate processed with the second protective film in step S14, the second prepreg, and the second copper foil in a bottom-up order.

[0023] Step S18, after pressing, according to the design data, laser third blind hole, second mechanical through hole, copper plating, and making circuit on the second copper foil of the upper and lower layers, and then removing the second protective film, and then producing according to the normal process to complete the production of the rigid-flex printed circuit board.

[0024] Further, in step S6, the thickness of the adhesive material is 0.01-0.05mm. The greater the thickness, the greater the overall difference of the first product bending area, which is not conducive to making ultra-fine lines on the fourth upper copper foil and the fifth lower copper foil. The window size corresponding to the position of the first product bending area is 0.1-0.2mm smaller than the size of the first product bending area on one side.

[0025] Further, in steps S7, S12 and S17, buffer materials and mirror steel plates are placed on the upper and lower layers during lamination to ensure the filling performance between the soft board materials and the adhesive materials and the flatness of the board surface.

[0026] Further, in step S7, the heating rate during pressing is 1.5-4℃ / min, the pressing pressure is 250-350psi, the maximum temperature is 160-185℃, and the holding time at the maximum temperature is 40-100 minutes.

[0027] Further, in step S8, when making the circuit, a vacuum film press is used to press the dry film special for ultra-fine lines to meet the filling performance of the dry film in the first product bending area and avoid the generation of film bubbles. The vacuum film pressing temperature is 60-120℃, the vacuum degree is 0-2hPa, and the pressing time is 15-35 seconds.

[0028] And an LDI exposure machine is used to make the circuit, and the exposure energy is 9-12 grids.

[0029] Further, in step S9, when processing the first protective film in the first product bending area and the second product bending area, the size of the first protective film is 0.125-0.5mm smaller than the size of the first product bending area and the second product bending area.

[0030] In step S14, when processing the second protective film in the first product bending area and the second product bending area, the size of the second protective film is 0.125-0.25mm smaller than the size of the first product bending area and the second product bending area.

[0031] The first protective film and the second protective film can be dissolved and removed by chemical reagents.

[0032] Further, the first prepreg adhesive sheet in step S10 is a low-flow prepreg adhesive sheet, and the window size is 0.1-0.2mm larger than the size of the first product bending area and the second product bending area.

[0033] The second prepreg adhesive sheet in step S15 is a low-flow prepreg adhesive sheet, and the window size is 0.05-0.1mm larger than the size of the first product bending area and the second product bending area.

[0034] Further, the temperature rising rate of the pressing in steps S12 and S17 is 1.5-4℃ / min, the pressing pressure is 350-450psi, the maximum temperature is 180-215℃, and the holding time at the maximum temperature is 90-120min.

[0035] Further, in the line manufacturing in steps S13 and S18, the copper foil of the first product bending area and the second product bending area is etched to expose the first protective film or the second protective film, and the first protective film and the second protective film are removed by using a special film stripping device, and the film stripping speed is 1.0-2.0m / min, and the film stripping temperature is 50-58℃.

[0036] In a second aspect, the embodiment of the present application provides a rigid-flexible printed circuit board with multiple soft plates, which is manufactured by using the manufacturing process in the first aspect.

[0037] Compared with the prior art, the technical scheme of the embodiment of the present application has the following beneficial effects:

[0038] The present application provides a rigid-flexible printed circuit board with multiple soft plates, which uses a buffer material and a mirror surface steel plate during pressing, so as to reduce the height difference of the soft plate and ensure the flatness of the plate, uses vacuum film pressing and LDI exposure during line manufacturing, the vacuum film pressing can completely attach the dry film to the bending area of the soft plate with height difference, solves the problem of film pressing bubbles, the high depth of field function of the LDI exposure machine directly transfers the image to the bending area of the soft plate with height difference, solves the problem of poor exposure, and can produce ultra-fine lines in the bending area of the soft plate. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a structure schematic diagram after the first soft plate is attached with the cover film in step S1 of embodiment 1.

[0040] Figure 2 is a structure schematic diagram after the second soft plate is attached with the cover film in step S2 of embodiment 1.

[0041] Figure 3 is a structure schematic diagram after the third soft plate is attached with the cover film in step S3 of embodiment 1.

[0042] Figure 4is a structural schematic diagram of the fourth soft plate in step S4 of Example 1.

[0043] Figure 5 is a structural schematic diagram of the fifth soft plate in step S5 of Example 1.

[0044] Figure 6 is a structural schematic diagram of the structure after the windowing of the adhesive material in step S6 of Example 1.

[0045] Figure 7 is a structural schematic diagram of the structure after lamination and pressing in step S7 of Example 1.

[0046] Figure 8 is a structural schematic diagram of the structure after the attachment of the fifth cover film in step S8 of Example 1.

[0047] Figure 9 is a structural schematic diagram of the structure after the processing of the first protective film in step S9 of Example 1.

[0048] Figure 10 is a structural schematic diagram of the structure after the windowing of the first prepreg in step S10 of Example 1.

[0049] Figure 11 is a structural schematic diagram of the first copper foil in step S11 of Example 1.

[0050] Figure 12 is a structural schematic diagram of the structure after lamination and pressing in step S12 of Example 1.

[0051] Figure 13 is a structural schematic diagram of the structure after the removal of the first protective film in step S13 of Example 1.

[0052] Figure 14 is a structural schematic diagram of the structure after the processing of the second protective film in step S14 of Example 1.

[0053] Figure 15 is a structural schematic diagram of the structure after the windowing of the second prepreg in step S15 of Example 1.

[0054] Figure 16 is a structural schematic diagram of the second copper foil in step S16 of Example 1.

[0055] Figure 17 is a structural schematic diagram of the structure after lamination and pressing in step S17 of Example 1.

[0056] Figure 18 is a structural schematic diagram of the finished rigid-flexible board product obtained in step S18 of Example 1.

[0057] Figure 19 is a structural schematic diagram of the finished rigid-flexible board product obtained in step S19 of Example 2.

[0058] Reference numerals: 1 - fourth soft plate; 2 - second soft plate; 3 - first soft plate; 4 - third soft plate; 5 - fifth soft plate; 6 - adhesive material; 7 - first prepreg; 8 - first copper foil; 9 - second prepreg; 10 - second copper foil; 11 - first blind hole; 12 - first mechanical through hole; 13 - second blind hole; 14 - third blind hole; 15 - second mechanical through hole; 16 - first protective film; 17 - second protective film; 18 - buffer material; 19 - mirror surface steel plate; A - first finished product bending area; B - second finished product bending area;

[0059] 1-1 - fourth upper copper foil; 1-2 - fourth cover film; 2-1 - second upper copper foil; 2-2 - second cover film; 3-1 - first upper copper foil; 3-2 - first lower copper foil; 3-3 - first upper cover film; 3-4 - first lower cover film; 4-1 - third lower copper foil; 4-2 - third cover film; 5-1 - fifth lower copper foil; 5-2 - fifth cover film. DETAILED DESCRIPTION

[0060] In the description of the present application, it should be understood that the orientation words such as "inner, outer", "upper, lower", "left, right" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, therefore cannot be understood as a limitation on the scope of protection of the present application.

[0061] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0062] Example 1

[0063] A bending area ultra-fine line processing process of a rigid-flex printed circuit board with multi-layer soft plate, comprising the following steps:

[0064] Step S1, providing a first soft plate 3 of a rigid-flex printed circuit board, the supplier of the first soft plate 3 is Taiwan Hong Electronic Material Co., Ltd., the model is 0.001 T / T OZ, the first soft plate 3 comprises a first upper copper foil 3-1 and a first lower copper foil 3-2, a circuit pattern is made on the first upper copper foil 3-1 and the first lower copper foil 3-2 as required and a circuit quality inspection is performed, and a first upper cover film 3-3 and a first lower cover film 3-4 are respectively attached to the upper and lower circuit surface layers, as shown in Figure 1 ;

[0065] The supplier of the first upper cover film 3-3 and the first lower cover film 3-4 is Taiyo Nippon Sanso Corporation, and the model number is FHK0315;

[0066] In step S2, a second soft plate 2 of the rigid-flex printed circuit board is provided. The supplier of the second soft plate 2 is Taiyo Nippon Sanso Corporation, and the model number is 0.0008 T / T OZ. The second soft plate 2 comprises a second upper copper foil 2-1. A circuit pattern is made on the second upper copper foil 2-1 according to requirements, and a circuit quality inspection is performed. A second cover film 2-2 is attached to the circuit surface, as shown in FIG. 2. Figure 2

[0067] The supplier of the second cover film 2-2 is Taiyo Nippon Sanso Corporation, and the model number is FHK0315.

[0068] In step S3, a third soft plate 4 of the rigid-flex printed circuit board is provided. The supplier of the third soft plate 4 is Taiyo Nippon Sanso Corporation, and the model number is 0.0008 T / T OZ. The third soft plate 4 comprises a third lower copper foil 4-1. A circuit pattern is made on the third lower copper foil 4-1 according to requirements, and a circuit quality inspection is performed. A third cover film 4-2 is attached to the circuit surface, as shown in FIG. 4. Figure 3

[0069] The supplier of the third cover film 4-2 is Taiyo Nippon Sanso Corporation, and the model number is FHK0315.

[0070] In step S4, a fourth soft plate 1 of the rigid-flex printed circuit board is provided. The supplier of the fourth soft plate 1 is Taiyo Nippon Sanso Corporation, and the model number is 0.0005 T / T OZ. The fourth soft plate 1 comprises a fourth upper copper foil 1-1, as shown in FIG. 5. Figure 4

[0071] In step S5, a fifth soft plate 5 of the rigid-flex printed circuit board is provided. The supplier of the fifth soft plate 5 is Taiyo Nippon Sanso Corporation, and the model number is 0.0005 T / T OZ. The fifth soft plate 5 comprises a fifth lower copper foil 5-1, as shown in FIG. 6. Figure 5

[0072] In step S6, an adhesive material 6 is provided. The adhesive material 6 is pure glue, and the supplier is Taiyo Nippon Sanso Corporation, and the model number is BT25. A window is opened at the position of the first product bending area A, and the size of the window is 0.125 mm smaller than the size of the first product bending area A on one side. The second product bending area B is not treated, as shown in FIG. 7. Figure 6

[0073] ​​​​​Step S7, in turn, the fifth soft plate 5, adhesive material 6, the third soft plate 4, adhesive material 6, the first soft plate 3, adhesive material 6, the second soft plate 2, adhesive material 6, the fourth soft plate 1 are stacked in turn from bottom to top, and RCF buffer material 18 and mirror steel plate 19 are placed in turn on the upper and lower surfaces during stacking, and then pressed, the pressing rate is 3℃ / min, the pressing pressure is 300psi, the maximum temperature is 170℃, and the holding time at the maximum temperature is 90 minutes, as shown in Figure 7 ;

[0074] Step S8, after pressing, laser first blind hole 11, first mechanical through hole 12, copper plating are made according to the design data, and then the circuit is made on the fifth lower copper foil 5-1 of the fifth soft plate 5 and the fourth upper copper foil 1-1 of the fourth soft plate 1, and then the fourth cover film 1-2 is attached to the circuit surface of the fourth soft plate 1 and the fifth cover film 5-2 is attached to the circuit surface of the fifth soft plate 5, as shown in Figure 8 ;

[0075] When making the circuit, a vacuum laminating machine is used to press the dry film special for ultra-fine circuit to meet the dry film filling performance of the first product bending area A, so as to avoid the generation of laminating bubbles, the vacuum laminating temperature is 80℃, the vacuum degree is 2hPa, and the pressing time is 25 seconds, and at the same time, an LDI exposure machine is used for production to avoid the exposure failure caused by the height difference of the first product bending area A, and the exposure energy is 10 grids;

[0076] Step S9, a layer of first protective film 16 is attached to the surface of the fourth cover film 1-2 and the fifth cover film 5-2 by using a vacuum laminating machine, and then exposed and developed, after development, only the first protective film 16 of the first product bending area A and the second product bending area B is reserved, and the size of the first protective film 16 is 0.125mm smaller than that of the first product bending area A and the second product bending area B, as shown in Figure 9 ;

[0077] Step S10, prepare the first semi-cured adhesive sheet 7, the supplier of the first semi-cured adhesive sheet 7 is Taigu Electronic Materials Co., Ltd., the model is 1037 Low flow, and the window is opened at the positions corresponding to the first product bending area A and the second product bending area B, and the size of the window is 0.15mm larger than that of the first product bending area A and the second product bending area B, as shown in Figure 10 ;

[0078] Step S11, prepare the first copper foil 8, as shown in Figure 11 ;

[0079] Step S12, in the order from bottom to top, the first copper foil 8, the first prepreg 7, the multi-layer soft plate processed with the first protective film 16 in step S9, the first prepreg 7, and the first copper foil 8 are laminated, and the RCF buffer material 18 and the mirror surface steel plate 19 are placed in the upper and lower layers respectively in sequence during lamination, and then pressing is performed, the pressing temperature rising rate is 3.5℃ / min, the pressing pressure is 400psi, the highest temperature is 195℃, and the holding time at the highest temperature is 90 minutes, as shown in Figure 12 ;

[0080] Step S13, after pressing, laser second blind hole 13 and copper plating are made according to the design data, and the circuit is made on the first copper foil 8 in the upper and lower layers, the copper foil of the first product bending area A and the second product bending area B is etched, the first protective film 16 is exposed, and then the first protective film 16 is removed by stripping film process, the stripping film speed is 1.0m / min, and the stripping film temperature is 53℃, as shown in Figure 13 ;

[0081] Step S14, a layer of second protective film 17 is attached to the surface of the fourth cover film 1-2 and the fifth cover film 5-2 by using a vacuum film pressing machine, and then exposure and development are performed, and after development, only the second protective film 17 of the first product bending area A and the second product bending area B is reserved, and the size of the second protective film 17 is 0.2mm smaller than that of the first product bending area A and the second product bending area B, as shown in Figure 14 ;

[0082] Step S15, the second prepreg 9 is prepared, the supplier of the second prepreg 9 is Taigu Electronic Material Co., Ltd., the model is 106 Low flow, and the windowing is performed at the positions corresponding to the first product bending area A and the second product bending area B, and the windowing size is 0.1mm larger than that of the first product bending area A and the second product bending area B, as shown in Figure 15 ;

[0083] Step S16, the second copper foil 10 is prepared, as shown in Figure 16 ;

[0084] Step S17, in the order from bottom to top, the second copper foil 10, the second prepreg 9, the multi-layer plate processed with the second protective film 17 in step S14, the second prepreg 9, and the second copper foil 10 are laminated, and the RCF buffer material 18 and the mirror surface steel plate 19 are placed in the upper and lower layers respectively in sequence during lamination, and then pressing is performed, the pressing temperature rising rate is 3.5℃ / min, the pressing pressure is 400psi, the highest temperature is 195℃, and the holding time at the highest temperature is 90 minutes, as shown in Figure 17 ;

[0085] Step S18, after pressing, according to the design data, laser third blind hole 14, second mechanical through hole 15, copper plating, and circuit on the upper and lower layers of the second copper foil 10, when making the circuit, etching all the copper foil of the first product bending area A and the second product bending area B, exposing the second protective film 17, then stripping the film process to remove the second protective film 17, stripping speed: 1.5 m / min, stripping temperature 56℃, then according to the normal process, the production of rigid-flex board finished product is completed, as shown in Figure 18 .

[0086] Example 2

[0087] A bending area ultra-fine circuit processing technology of a rigid-flex board with multiple layers of soft plates, comprising the following steps:

[0088] Step S1, providing a first soft plate 3 of a rigid-flex board, the supplier of the first soft plate 3 is Taiwan Hong Electronic Material Co., Ltd., the model is 0.0008 T / T OZ, the soft plate includes a first upper copper foil 3-1 and a first lower copper foil 3-2, a circuit pattern is made on the first upper copper foil 3-1 and the first lower copper foil 3-2 according to requirements and circuit quality inspection is performed, and a first upper cover film 3-3 and a first lower cover film 3-4 are respectively attached on the upper and lower circuit surfaces, the supplier of the first upper cover film 3-3 and the first lower cover film 3-4 is Taiwan Hong Electronic Material Co., Ltd., and the model is FHK0315;

[0089] Step S2, providing a second soft plate 2 of a rigid-flex board, the supplier of the second soft plate 2 is Taiwan Hong Electronic Material Co., Ltd., the model is 0.0008 T / T OZ, the second soft plate 2 includes a second upper copper foil 2-1, a circuit pattern is made on the second upper copper foil 2-1 according to requirements and circuit quality inspection is performed, and a second cover film 2-2 is attached on the circuit surface, the supplier of the second cover film 2-2 is Taiwan Hong Electronic Material Co., Ltd., and the model is FHK0315;

[0090] Step S3, providing a third soft plate 4 of a rigid-flex board, the supplier of the third soft plate 4 is Taiwan Hong Electronic Material Co., Ltd., the model is 0.0008 T / T OZ, the third soft plate 4 includes a third lower copper foil 4-1, a circuit pattern is made on the third lower copper foil 4-1 according to requirements and circuit quality inspection is performed, and a third cover film 4-2 is attached on the circuit surface, the supplier of the third cover film 4-2 is Taiwan Hong Electronic Material Co., Ltd., and the model is FHK0315;

[0091] Step S4, providing a fourth soft plate 1 of a rigid-flex board, the supplier of the fourth soft plate 1 is Taiwan Hong Electronic Material Co., Ltd., the model is 0.0005 T / T OZ, and the fourth soft plate 1 includes a fourth upper copper foil 1-1;

[0092] Step S5, a fifth soft plate 5 of the soft and hard combination plate is provided, the supplier of the fifth soft plate 5 is Taiwan Hong Electronic Material Co., Ltd., the model is 0.0005 T / T OZ, and the fifth soft plate 5 comprises a fifth lower copper foil 5-1;

[0093] Step S6, an adhesive material 6 is provided, the adhesive material 6 is pure glue, the supplier is Taiwan Hong Electronic Material Co., Ltd., the model is BT25, a window is opened at a position corresponding to the first product bending area A, and the size of the window is 0.125 mm smaller than the size of the first product bending area A on one side; and no treatment is performed on a position corresponding to the second product bending area B;

[0094] Step S7, the fifth soft plate 5, the adhesive material 6, the third soft plate 4, the adhesive material 6, the first soft plate 3, the adhesive material 6, the second soft plate 2, the adhesive material 6 and the fourth soft plate 1 are sequentially laminated in a bottom-up order, RCF buffer materials 18 and mirror steel plates 19 are sequentially arranged on the upper and lower surfaces during lamination, and then pressing is performed, the pressing temperature rising rate is 3 ℃ / min, the pressing pressure is 280 psi, the highest temperature is 160 ℃, and the pressure holding time in the highest temperature section is 90 min;

[0095] Step S8, after pressing, a laser first blind hole 11, a first mechanical through hole 12 and copper plating are manufactured according to design data, and a circuit is manufactured on the fifth lower copper foil 5-1 of the fifth soft plate 5 and the fourth upper copper foil 1-1 of the fourth soft plate 1, then a fourth cover film 1-2 is attached to the circuit surface of the fourth soft plate 1, and a fifth cover film 5-2 is attached to the circuit surface of the fifth soft plate 5; during the manufacturing of the circuit, a vacuum laminator is used to press a dry film special for ultra-fine circuits, so that the dry film filling performance of the first product bending area A is met, and air bubbles generated during pressing are avoided, the vacuum laminating temperature is 75 ℃, the vacuum degree is 2 hPa, and the pressing time is 30 s; at the same time, an LDI exposure machine is used for production, so that the exposure of the first product bending area A is not poor due to the height difference, and the exposure energy is 10 grids;

[0096] Step S9, a first protective film 16 is attached to the surfaces of the fourth cover film 1-2 and the fifth cover film 5-2 by using a vacuum laminator, and then exposure and development are performed; after development, only the first protective film 16 of the first product bending area A and the second product bending area B is reserved, and the size of the first protective film 16 is 0.125 mm smaller than the size of the first product bending area A and the second product bending area B;

[0097] Step S10, a first prepreg 7 is prepared, the supplier of the first prepreg 7 is Taiwan Guang Electronic Material Co., Ltd., the model is 1037 Low flow, and windows are opened at positions corresponding to the first product bending area A and the second product bending area B respectively, and the size of the window is 0.15 mm larger than the size of the first product bending area A and the second product bending area B;

[0098] Step S11, prepare the first copper foil 8;

[0099] Step S12, in the order from bottom to top, sequentially laminate the first copper foil 8, the first prepreg 7, the multi-layer soft plate with the first protective film 16 processed in step S9, the first prepreg 7 and the first copper foil 8, and then press, with the temperature rising rate of 3.8℃ / min, the pressure of 420psi, the highest temperature of 195℃ and the holding time of 90 minutes in the highest temperature section;

[0100] Step S13, after pressing, according to the design data, make the laser second blind hole 13 and plate copper, and etch the copper foil of the first product bending area A and the second product bending area B on the first copper foil 8 of the upper and lower surfaces to expose the first protective film 16, and then remove the first protective film 16 by stripping film process, with the stripping film speed of 1.2m / min and the stripping film temperature of 53℃;

[0101] Step S14, attach a layer of second protective film 17 on the surface of the fourth cover film 1-2 and the fifth cover film 5-2 by using vacuum film press, and then expose and develop, and after developing, only the second protective film 17 of the first product bending area A and the second product bending area B is reserved, and the size of the second protective film 17 is 0.125mm smaller than that of the first product bending area A and the second product bending area B;

[0102] Step S15, prepare the second prepreg 9, the supplier of which is Taigu Electronic Materials Co., Ltd., and the model is 106 Low flow, and the second prepreg 9 is windowed at the positions corresponding to the first product bending area A and the second product bending area B, with the windowing size being 0.075mm larger than that of the first product bending area A and the second product bending area B;

[0103] Step S16, prepare the second copper foil 10;

[0104] Step S17, in the order from bottom to top, sequentially laminate the second copper foil 10, the second prepreg 9, the multi-layer plate with the second protective film 17 processed in step S14, the second prepreg 9 and the second copper foil 10, and then press, with the temperature rising rate of 3.8℃ / min, the pressure of 420psi, the highest temperature of 195℃ and the holding time of 90 minutes in the highest temperature section;

[0105] Step S18, repeat steps S13 to S17 once;

[0106] Step S19, after pressing, according to the design data to make laser third blind hole 14, second mechanical through hole 15, copper plating, and the second copper foil 10 on the upper and lower surface layer to make the circuit, when making the circuit, the copper foil of the first product bending area A and the second product bending area B is etched off, and the second protective film 17 is exposed, then the film stripping process is used to remove the second protective film 17, the film stripping speed is 1.5 m / min, the film stripping temperature is 56℃, then the normal process is used to produce, and the soft and hard combination board product is completed, such as Figure 19

[0107] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be covered by the scope of the claims of the present application.​

Claims

1. A process for processing ultra-fine circuits in the bending area of ​​a rigid-flexible board with multiple layers of flexible boards, characterized in that: The following steps are involved: Step S1, providing a first flexible board (3) of a rigid-flexible board, wherein the first flexible board (3) comprises a first upper copper foil (3-1) and a first lower copper foil (3-2), producing circuit patterns on the first upper copper foil (3-1) and the first lower copper foil (3-2) as required, performing circuit quality inspection, and laminating a first upper covering film (3-3) and a first lower covering film (3-4) on the upper and lower circuit surfaces, respectively; Step S2, providing a second flexible board (2) of a rigid-flexible board, wherein the second flexible board (2) comprises a second upper copper foil (2-1), producing a circuit pattern on the second upper copper foil (2-1) as required, performing a circuit quality inspection, and laminating a second covering film (2-2) on the surface of the circuit; Step S3, providing a third soft board (4) of a hard-flex board, wherein the third soft board (4) comprises a third lower copper foil (4-1), producing a circuit pattern on the third lower copper foil (4-1) as required, performing a circuit quality inspection, and laminating a third covering film (4-2) on the surface of the circuit; Step S4, providing a fourth flexible board (1) of a rigid-flexible board, wherein the fourth flexible board (1) comprises a fourth upper copper foil (1-1); Step S5, providing a fifth flexible board (5) of a rigid-flexible board, wherein the fifth flexible board (5) comprises a fifth lower layer copper foil (5-1); Step S6, providing adhesive material (6), opening a window at the position corresponding to the bending area (A) of the first finished product, and not performing any treatment at the position corresponding to the bending area (B) of the second finished product; Step S7, stacking and pressing the fifth soft board (5), the adhesive material (6), the third soft board (4), the adhesive material (6), the first soft board (3), the adhesive material (6), the second soft board (2), the adhesive material (6), and the fourth soft board (1) in order from bottom to top; Step S8, after lamination, making a laser first blind hole (11), a first mechanical through hole (12), copper plating according to the design data, and making circuits on the fifth lower copper foil (5-1) and the fourth upper copper foil (1-1), and then laminating a fourth covering film (1-2) on the circuit surface of the fourth flexible board (1), and laminating a fifth covering film (5-2) on the circuit surface of the fifth flexible board (5); Step S9, processing a layer of first protective film (16) on the first finished product bending region (A) and the second finished product bending region (B) of the fourth covering film (1-2) and the fifth covering film (5-2); Step S10, preparing a first semi-cured adhesive sheet (7), and opening windows at positions corresponding to the first finished product bending area (A) and the second finished product bending area (B); Step S11, preparing a first copper foil (8); Step S12, stacking and pressing the first copper foil (8), the first semi-cured adhesive sheet (7), the multi-layer soft board with the first protective film (16) processed in step S9, the first semi-cured adhesive sheet (7) and the first copper foil (8) in order from bottom to top; Step S13: After lamination, a second laser blind hole (13) is made according to the design data, copper is plated, and circuits are made on the first copper foil (8) on the upper and lower surfaces, and then the first protective film (16) is removed; Step S14, processing a second protective film (17) on the first finished product bending region (A) and the second finished product bending region (B) of the fourth covering film (1-2) and the fifth covering film (5-2); Step S15, preparing a second semi-cured adhesive sheet (9), and opening windows at positions corresponding to the first finished product bending area (A) and the second finished product bending area (B); Step S16, preparing a second copper foil (10); Step S17, stacking and pressing the second copper foil (10), the second semi-cured adhesive sheet (9), the multilayer board on which the second protective film (17) is processed in step S14, the second semi-cured adhesive sheet (9), and the second copper foil (10) in order from bottom to top; Step S18: After lamination, a third laser blind hole (14), a second mechanical through hole (15), copper plating, and circuits are made on the second copper foil (10) on the upper and lower surfaces according to the design data. The second protective film (17) is then removed, and the production is completed according to the normal process to complete the production of the rigid-flexible board.

2. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: In step S6, the thickness specification of the adhesive material (6) is 0.01-0.05 mm, and the window size corresponding to the position of the first finished product bending area (A) is 0.1-0.2 mm smaller than the size of the first finished product bending area (A) on one side.

3. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: In steps S7, S12 and S17, a buffer material (18) and a mirror steel plate (19) are placed on the upper and lower surfaces respectively during lamination to ensure the filling performance between the soft board material and the adhesive material (6) and the flatness of the board surface.

4. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: The heating rate during pressing in step S7 is 1.5-4°C / min, the pressing pressure is 250-350psi, the maximum temperature is 160-185°C, and the holding time in the highest temperature section is 40-100 minutes.

5. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: When making the circuit in step S8, a vacuum laminator is used to laminate the dry film specially used for ultra-fine circuits to meet the filling performance of the dry film in the bending area (A) of the first finished product. The vacuum lamination temperature is 60-120°C, the vacuum degree is 0-2hPa, and the pressing time is 15-35 seconds. The circuit is made using an LDI exposure machine with an exposure energy of 9-12 frames.

6. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: Step S9: when processing the first protective film (16) in the first finished product bending region (A) and the second finished product bending region (B), the size of the first protective film (16) is 0.125-0.5 mm smaller than the size of the first finished product bending region (A) and the second finished product bending region (B); Step S14: when processing the second protective film (17) on the first finished product bending region (A) and the second finished product bending region (B), the size of the second protective film (17) is 0.125-0.25 mm smaller than the size of the first finished product bending region (A) and the second finished product bending region (B); Both the first protective film (16) and the second protective film (17) can be dissolved and removed by chemical reagents.

7. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: In step S10, the first semi-cured adhesive sheet (7) is a low-flow semi-cured adhesive sheet, and the window size is 0.1-0.2 mm larger than the size of the first finished product bending area (A) and the second finished product bending area (B); In step S15, the second semi-cured adhesive sheet (9) is a low-flow semi-cured adhesive sheet, and the window size is 0.05-0.1 mm larger than the size of the first finished product bending area (A) and the second finished product bending area (B).

8. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: The heating rate of the pressing in step S12 and step S17 is 1.5-4°C / min, the pressing pressure is 350-450psi, the maximum temperature is 180-215°C, and the holding time in the highest temperature section is 90-120 minutes.

9. The process for processing ultra-fine circuits in the bending area of ​​a rigid-flex board with a multi-layer flexible board according to claim 1, characterized in that: During the circuit production in step S13 and step S18, the copper foils of the first finished product bending region (A) and the second finished product bending region (B) are all etched away to expose the first protective film (16) or the second protective film (17), and a dedicated film stripping device is used to remove the first protective film (16) and the second protective film (17). The film stripping speed is 1.0-2.0 m / min and the film stripping temperature is 50-58°C.

10. A rigid-flex board with multiple layers of flexible boards, characterized in that: The invention is prepared by the processing technology described in any one of claims 1 to 9.

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