Rigid-flex board and manufacturing method thereof

Abstract

The invention provides a rigid-flex board and a manufacturing method thereof, and the manufacturing method comprises the steps: providing an auxiliary supporting plate which is provided with a first through hole; a first buffer pad, a hard substrate and an adhesive plate are sequentially stacked on the auxiliary supporting plate, and a second through hole and a hard plate via hole are formed in the first buffer pad and the hard substrate respectively; enabling a pin to pass through the adhesive plate, and then to pass through the hard board via hole, the second through hole and the first through hole in sequence; the soft substrate and the second buffer pad are continuously stacked to obtain a combined plate, and soft plate conduction holes corresponding to the conductive pins are formed in the soft substrate; the composition board is pre-cured; the rigid-flex board is obtained by press-fitting the hard substrate and the soft substrate through press-fitting forming, the technical problems that in the prior art, traditional pin insertion needles need additional procedure welding and auxiliary material fixing, and the assembly space and cost are increased can be solved, the uncovering process in the traditional rigid-flex board manufacturing process can be omitted, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of PCB technology, and more particularly to a rigid-flex PCB and its manufacturing method. Background Technology

[0002] Rigid-flex boards, with their rigid areas supporting chips and flexible areas adapting to narrow or irregular spaces, have become the core carriers of sensors. However, as sensors rapidly evolve towards miniaturization and high integration, the demand for compressed assembly space is becoming increasingly stringent. This has led to rigid-flex boards reducing some assembly space through circuit board design to move towards miniaturization.

[0003] Currently, although existing rigid-flex PCBs have reduced some assembly space through circuit board design, they are still flat two-dimensional structures that cannot directly integrate pins and headers. Additional soldering processes are required, which increases assembly complexity, space redundancy, and production costs. In addition, rigid-flex PCBs usually require additional soldering of pins and headers after SMT assembly. This process relies on auxiliary materials to fix the pins and headers, which increases assembly space. Soldering the headers requires additional PCBA soldering processes and increases costs, resulting in cumbersome processes and low production efficiency. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a rigid-flex board and its manufacturing method, which simplifies the process, reduces production costs, and improves production efficiency.

[0005] To solve the above technical problems, a method for manufacturing a rigid-flex PCB provided by this invention is provided, comprising the following steps:

[0006] a. Material Preparation: Prepare one rigid substrate, one flexible substrate, one adhesive board, one auxiliary support plate, one first buffer pad, one second buffer pad, and several conductive pins; the rigid substrate includes a rigid upper conductor layer, a rigid dielectric layer, and a rigid lower conductor layer stacked from top to bottom, and several rigid through holes are provided on the rigid substrate to connect the rigid upper conductor layer and the rigid lower conductor layer; the flexible substrate includes a flexible upper conductor layer, a flexible dielectric layer, and a flexible lower conductor layer stacked from top to bottom, and several flexible through holes are provided on the flexible substrate to connect the flexible upper conductor layer and the flexible lower conductor layer; several first through holes are provided on the auxiliary support plate; several second through holes are provided on the first buffer pad, and the first through holes, second through holes, rigid through holes, and flexible through holes are aligned; the conductive pins include leads and metal caps connected to the top of the leads;

[0007] b. First stacking: Place the first buffer pad, rigid substrate, and adhesive board on the auxiliary support plate in sequence, and align the first through hole, the second through hole, and the rigid board through hole.

[0008] c. Pin insertion: After the lead of the conductive pin passes through the adhesive plate, it is sequentially inserted into the through hole, the second through hole, and the first through hole of the rigid plate.

[0009] d. Second stacking: The flexible substrate and the second buffer pad are stacked on the adhesive board in sequence, and the through holes of the flexible board are aligned with the through holes of the rigid board to obtain the combined board;

[0010] e. Pre-curing: The composite board is hot-pressed with an iron to allow the adhesive to initially cure;

[0011] f. Pressing and shaping: The composite panels are hot-pressed using a pressing machine to cure and shape the adhesive panels;

[0012] g. Auxiliary material removal: Remove the combined plate from the auxiliary tray and peel off the first and second buffer pads to obtain the soft and hard combined plate.

[0013] Step a cuts out the first cutout groove on the adhesive board. Step g also requires cutting out the second cutout groove on the rigid substrate to align with the first cutout groove, so as to form a flexible board area on the rigid-flex board.

[0014] Step a requires preparing four positioning pins and drilling alignment holes on all four sides of the auxiliary tray, the first buffer pad, the rigid substrate, the adhesive board, the flexible substrate, and the second buffer pad; in step b, first insert the positioning pins into the positioning holes of the auxiliary tray, and then align the positioning holes with the positioning pins to stack the first buffer pad, the rigid substrate, and the adhesive board on the auxiliary tray in sequence; in step d, align the positioning holes with the positioning pins to stack the flexible substrate and the second buffer pad on the adhesive board in sequence.

[0015] The diameter of the metal cap is 0.25–0.35 mm larger than the diameter of the pin. The thickness of the auxiliary pad is greater than the length of the pin. The diameter of the first through hole is 0.08–0.12 mm larger than the diameter of the pin. The diameters of the second through hole and the rigid board through hole are 0.03–0.08 mm larger than the diameter of the pin. The diameter of the flexible board through hole is 0.1–0.3 mm smaller than the diameter of the metal cap. The thickness of the metal cap is less than twice the thickness of the bonding plate.

[0016] The bonding board is an epoxy resin film with a thickness of 0.04 to 0.06 mm.

[0017] The first and second buffer pads are TPX or a three-in-one composite film. The three-in-one composite film includes an upper release film, a buffer layer, and a lower release film stacked from top to bottom. The upper and lower release films are made of PET, PA, or PP, and the buffer layer is made of PE or PP.

[0018] The conductive pin is made of copper-zinc alloy.

[0019] In step e, the pre-curing time is 3–5 seconds, and the hot-pressing temperature of the iron is <150°C; in step f, the hot-pressing temperature of the press is 170–190°C, and the pressure is 130 bar / cm. 2 ~170 bar / cm 2 The pre-compression time is 30-50 seconds, and the molding time is 150-300 seconds.

[0020] In step a, the fabrication steps of the rigid substrate include material preparation, drilling, copper plating, electroplating, dry film lamination, exposure and development, etching, AOI, solder mask, surface treatment, electrical testing, final inspection, and laser shaping; the fabrication steps of the flexible substrate include material preparation, drilling, copper plating, electroplating, dry film lamination, exposure and development, etching, AOI, solder mask, surface treatment, electrical testing, final inspection, and laser shaping.

[0021] To solve the above-mentioned technical problems, a rigid-flex board provided by the present invention is provided, comprising a plurality of conductive pins and a flexible substrate, an adhesive board, and a rigid substrate stacked from top to bottom; the rigid substrate comprises a rigid upper conductor layer, a rigid dielectric layer, and a rigid lower conductor layer stacked from top to bottom, and a plurality of rigid through holes are provided on the rigid substrate to connect the rigid upper conductor layer and the rigid lower conductor layer; the flexible substrate comprises a flexible upper conductor layer, a flexible dielectric layer, and a flexible lower conductor layer stacked from top to bottom, and a plurality of flexible through holes are provided on the flexible substrate to connect the flexible upper conductor layer and the flexible lower conductor layer, and the rigid through holes are aligned with the flexible through holes; the conductive pins comprise leads and metal caps connected to the top of the leads, the bottom ends of the leads pass through the rigid through holes, and the metal caps are clamped between the flexible lower conductor layer and the rigid upper conductor layer to achieve conductivity between the flexible lower conductor layer and the rigid upper conductor layer; the adhesive board and the rigid substrate are respectively provided with corresponding first and second cutout grooves.

[0022] The beneficial effects of this invention are as follows: This invention provides a rigid-flex PCB and its manufacturing method. The method involves embedding conductive pins within the rigid-flex PCB, enabling conductivity between the conductors in the flexible and rigid substrates. It also allows communication with the outside world through the flexible substrate's through-holes, eliminating the need for additional welding processes, thus reducing costs and processing time. Furthermore, the conductive pins are fixed within the rigid-flex PCB using an adhesive plate, achieving fixation without auxiliary materials and compressing assembly space. This solves the technical problem of traditional conductive pins requiring additional welding processes and auxiliary material fixation. By directly pressing the flexible and rigid substrates together, the traditional open-cover process in rigid-flex PCB manufacturing is eliminated, reducing production costs and improving production efficiency. Attached Figure Description

[0023] Figure 1 An exploded structural diagram of the composite plate of the present invention is shown.

[0024] Figure 2 A cross-sectional view of the composite plate of the present invention is shown.

[0025] Figure 3 A cross-sectional view of the rigid-flex plate of the present invention is shown.

[0026] Reference numerals: 1. Rigid substrate, 10. Upper conductor layer of rigid substrate, 11. Lower conductor layer of rigid substrate, 12. Through hole of rigid substrate, 13. Second cutout groove, 14. 2. Flexible substrate, 20. Upper conductor layer of flexible substrate, 21. Lower conductor layer of flexible substrate, 22. Through hole of flexible substrate, 23. Adhesive board, 3. First cutout groove, 30. Auxiliary support plate, 4. First through hole, 40. Positioning hole, 41. First buffer pad, 5. Second through hole, 50. Second buffer pad, 6. Conductive pin, 7. Lead, 70. Metal cap, 71. Positioning pin, 8. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure.

[0028] Based on the embodiments described in this disclosure, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this disclosure.

[0029] refer to Figure 1-3 .

[0030] This invention provides a method for manufacturing a rigid-flex PCB, comprising the following steps:

[0031] a. Material preparation: Prepare one rigid substrate 1, one flexible substrate 2, one adhesive board 3, one auxiliary support plate 4, one first buffer pad 5, one second buffer pad 6, and several conductive pins 7; the rigid substrate 1 includes a rigid upper conductor layer 10, a rigid substrate dielectric layer 11, and a rigid substrate lower conductor layer 12 stacked from top to bottom, and the rigid substrate 1 is provided with several rigid substrate through holes 13 that connect the rigid upper conductor layer 10 and the rigid substrate lower conductor layer 12; the flexible substrate 2 includes flexible boards stacked from top to bottom. The flexible substrate 2 has an upper conductor layer 20, a flexible circuit dielectric layer 21, and a flexible circuit lower conductor layer 22. A plurality of flexible circuit through-holes 23 are provided on the flexible substrate 2 to connect the upper conductor layer 20 and the lower conductor layer 22. An auxiliary support plate 4 has a plurality of first through-holes 40. A first buffer pad 5 has a plurality of second through-holes 50. The first through-holes 40, second through-holes 50, rigid circuit through-holes 13, and flexible circuit through-holes 23 are aligned. The conductive pin 7 includes a lead 70 and a metal cap 71 connected to the top of the lead 70.

[0032] b. First stacking: The first buffer pad 5, the rigid substrate 1, and the adhesive board 3 are stacked on the auxiliary support plate 4 in sequence, and the first through hole 40, the second through hole 50, and the rigid board through hole 13 are aligned.

[0033] c. Pin insertion: After the lead 70 of the conductive pin 7 passes through the adhesive plate 3, it is sequentially inserted into the through hole 13, the second through hole 50, and the first through hole 40 of the rigid plate.

[0034] d. Second stacking: The flexible substrate 2 and the second buffer pad 6 are stacked on the adhesive board 3 in sequence, and the through hole 23 of the flexible board is aligned with the through hole 13 of the rigid board to obtain the combined board;

[0035] e. Pre-curing: The composite board is hot-pressed with an iron to allow the adhesive board 3 to be initially cured;

[0036] f. Pressing and shaping: The composite board is hot-pressed using a press to cure and shape the adhesive board 3;

[0037] g. Removal of auxiliary materials: Remove the combined plate from the auxiliary tray 4 and peel off the first buffer pad 5 and the second buffer pad 6 to obtain the soft and hard combined plate.

[0038] Specifically, a first buffer pad 5, a rigid substrate 1, and an adhesive plate 3 are stacked sequentially on the auxiliary support plate 4. Then, the pin 70 is passed through the adhesive plate 3 and then sequentially inserted into the rigid plate through-hole 13, the second through-hole 50, and the first through-hole 40. The flexible substrate 2 and the second buffer pad 6 are then stacked, so that the conductive pin 7 is embedded in the flexible-rigid bonding plate. This allows the conductors in the flexible substrate 2 and the rigid substrate 1 to conduct electricity, and it can also conduct electricity to the outside through the flexible plate through-hole 23 on the flexible substrate 2. No additional welding process is required, reducing costs and processing time. At the same time, the conductive pin 7 is fixed by being embedded in the flexible-rigid bonding plate through the adhesive plate 3, which can achieve fixation without auxiliary materials, compressing the assembly space. This solves the technical problem that traditional conductive pins 7 require additional welding processes and auxiliary materials for fixation, saving costs.

[0039] Step a involves cutting a first perforated groove 30 on the adhesive board 3. Step g requires cutting a second perforated groove 14 on the rigid substrate 1, aligning with the first perforated groove 30, to form a flexible board area on the rigid-flex board. It should be noted that the adhesive board 3 uses a low-flow adhesive material, allowing for the removal of adhesive from the flexible board area. After the flexible substrate 2 and rigid substrate 1 are laminated, the areas that do not require bending are bonded together with adhesive to form the rigid board area of ​​the rigid-flex board. The areas requiring bending are pre-cut by removing adhesive from the adhesive board 3 to form the first perforated groove 30. After the flexible substrate 2 and rigid substrate 1 are laminated, there is no adhesive in this area. Before SMT assembly, the rigid substrate 1 with no adhesive in this area is removed to form the second perforated groove 14, leaving only the flexible substrate 2 in this region, thus forming the flexible board area of ​​the rigid-flex board. This manufacturing method is simpler than the traditional rigid-flex PCB processing method, eliminating the need for the opening process in the traditional rigid-flex PCB manufacturing, thus saving production costs and time.

[0040] Step a requires preparing four positioning pins 8, and drilling alignment positioning holes 41 on all four sides of the auxiliary tray 4, the first buffer pad 5, the rigid substrate 1, the adhesive board 3, the flexible substrate 2, and the second buffer pad 6; in step b, first insert the positioning pins 8 into the positioning holes 41 of the auxiliary tray 4, and then align the positioning holes 41 with the positioning pins 8 and stack the first buffer pad 5, the rigid substrate 1, and the adhesive board 3 on the auxiliary tray 4 in sequence; in step d, align the positioning holes 41 with the positioning pins 8 and stack the flexible substrate 2 and the second buffer pad 6 on the adhesive board 3 in sequence.

[0041] The diameter of the metal cap 71 is 0.25–0.35 mm larger than the diameter of the pin 70 to prevent the conductive pin 7 from falling off; the thickness of the auxiliary pad 4 is greater than the length of the pin 70 to prevent the pin 70 from being pushed up during pressing, which would cause the conductive pin 7 to be not pressed firmly; the diameter of the first through hole 40 is 0.08–0.12 mm larger than the diameter of the pin 70 to facilitate the insertion of the pin 70; the diameters of the second through hole 50 and the rigid board through hole 13 are 0.03–0.08 mm larger than the diameter of the pin 70 to facilitate the insertion of the pin 70; the diameter of the flexible board through hole 23 is 0.1–0.3 mm smaller than the diameter of the metal cap 71 to prevent the flexible substrate 2 from failing to cover the metal cap 71 and to prevent the conductive pin 7 from falling off after pressing; the thickness of the metal cap 71 is less than twice the thickness of the adhesive plate 3 to prevent the metal cap 71 from not being firmly bonded.

[0042] The bonding plate 3 is an epoxy resin film with a thickness of 0.04 to 0.06 mm.

[0043] The first buffer pad 5 and the second buffer pad 6 are TPX or a three-in-one composite film. The three-in-one composite film consists of an upper release film, a buffer layer, and a lower release film stacked sequentially from top to bottom. The upper and lower release films are made of PET, PA, or PP, and the buffer layer is made of PE or PP. This solves the problems of delamination and glue overflow during multilayer board lamination, improving production efficiency and product yield.

[0044] The conductive pin 7 is made of copper-zinc alloy, which has the advantages of high hardness and good conductivity.

[0045] In step e, the pre-curing time is 3-5 seconds, and the hot pressing temperature of the iron is <150°C, so that the adhesive material of the adhesive board 3 is initially cross-linked and melted, quickly generating initial adhesion, temporarily fixing the relative positions of the hard substrate 1 and the soft substrate 2, ensuring that the conductive pin 7 is aligned with the through hole 23 of the soft board, and avoiding interlayer slippage in the subsequent pressing process.

[0046] In addition, heating can also promote the short-term flow of adhesive materials and help to expel interlayer air; in step f, the hot pressing temperature of the press is 170-190°C and the pressure is 130 bar / cm. 2 ~170 bar / cm 2The pre-pressing time is 30-50 seconds, which allows the adhesive material of the adhesive board 3 to initially melt and flow, filling the microscopic gaps between the rigid substrate 1 and the flexible substrate 2, removing air, and initially densifying the laminated structure. Gradually increasing the pressure can initially fix the laminated structure of the composite board and prevent subsequent slippage. Maintaining the temperature and pressure, the pressing is carried out for 150-300 seconds, which allows the adhesive material of the adhesive board 3 to complete the chemical curing reaction under high temperature and high pressure, fully cross-linking and curing, building mechanical adhesion and electrical insulation between the rigid substrate 1 and the flexible substrate 2, while ensuring tight bonding between the layers through continuous pressure.

[0047] In step a, the fabrication steps of the rigid substrate 1 include material preparation, drilling, copper plating (chemical copper plating on the hole walls), electroplating (thickening the copper layer), dry film lamination (photoresist film), exposure and development, etching (removing excess copper), AOI, solder resist, surface treatment, electrical testing, final inspection, and laser shaping. Copper plating and electroplating make the vias 13 conductive, achieving electrical interconnection between the upper and lower conductor layers of the rigid substrate 1. Then, dry film etching forms customized circuitry (such as pads and traces) on the surface of the rigid substrate 1 to match the soldering of the sensor / chip. Requirements; The fabrication steps of the flexible substrate 2 include material preparation, drilling, copper plating (chemical copper plating on the hole walls), electroplating (thickening the copper layer), dry film application (photoresist film), exposure and development, etching (removing excess copper), AOI, solder resist, surface treatment, electrical testing, final inspection, and laser shaping. Through copper plating and electroplating, the through holes 23 of the flexible board are made conductive, so that the conductive pins 7 can be electrically connected to external components. Then, through dry film etching, custom lines (such as pads and traces) are formed on the surface of the flexible substrate 2 to match the welding requirements of sensors / chips.

[0048] This invention provides a rigid-flex board, comprising a plurality of conductive pins 7 and a flexible substrate 2, an adhesive board 3, and a rigid substrate 1 stacked from top to bottom. The rigid substrate 1 comprises a rigid upper conductor layer 10, a rigid substrate dielectric layer 11, and a rigid substrate lower conductor layer 12 stacked from top to bottom, and the rigid substrate 1 is provided with a plurality of rigid substrate through holes 13 that connect the rigid upper conductor layer 10 and the rigid substrate lower conductor layer 12. The flexible substrate 2 comprises a flexible upper conductor layer 20, a flexible substrate dielectric layer 21, and a flexible substrate lower conductor layer 22 stacked from top to bottom, and the flexible substrate 2 is provided with a plurality of conductive pins 7. The flexible board through-hole 23 of the flexible board conductor layer 20 and the flexible board lower conductor layer 22 are aligned with the rigid board through-hole 13 and the flexible board through-hole 23; the conductive pin 7 includes a lead 70 and a metal cap 71 connected to the top of the lead 70. The bottom end of the lead 70 passes through the rigid board through-hole 13. The metal cap 71 is sandwiched between the flexible board lower conductor layer 22 and the rigid board upper conductor layer 10 to achieve conductivity between the flexible board lower conductor layer 22 and the rigid board upper conductor layer 10. The bonding board 3 and the rigid substrate 1 are respectively provided with corresponding first cutout groove 30 and second cutout groove 14.

[0049] The conductive pins 7 are directly embedded in the rigid-flex board, and the adhesive board 3 fixes and bonds the conductive pins 7. No additional welding process or auxiliary materials are required. The two-dimensional flat board is transformed into a 3D integrated structure. The conductive pins 7 are built-in, which reduces assembly space, process and cost. At the same time, the conductive pins 7 include metal caps 71 and pins 70. The metal caps 71 are larger than the through holes 23 of the flexible board, which can effectively prevent them from falling off and can conduct the conductors of the flexible board 2 and the rigid board 1. In addition, the flexible board area is formed by making the first hollow groove 30 and the second hollow groove 14, which is simpler than the traditional rigid-flex board processing method. It eliminates the opening process in the traditional rigid-flex board manufacturing, which can save manufacturing costs and time.

[0050] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for manufacturing a rigid-flex PCB, characterized in that, The method comprises the following steps: a. material preparation: prepare a hard substrate, a soft substrate, an adhesive plate, an auxiliary support plate, a first buffer pad, a second buffer pad, and a plurality of conductive pins; the hard substrate comprises a hard upper conductor layer, a hard medium layer, and a hard lower conductor layer stacked in order from top to bottom, and the hard substrate is provided with a plurality of hard substrate through holes for connecting the hard upper conductor layer and the hard lower conductor layer; the soft substrate comprises a soft upper conductor layer, a soft medium layer, and a soft lower conductor layer stacked in order from top to bottom, and the soft substrate is provided with a plurality of soft substrate through holes for connecting the soft upper conductor layer and the soft lower conductor layer; the auxiliary support plate is provided with a plurality of first through holes; the first buffer pad is provided with a plurality of second through holes, and the first through holes, the second through holes, the hard substrate through holes, and the soft substrate through holes are arranged in a matched manner; the conductive pins comprise a pin and a metal cap connected to the top end of the pin; b. first material stacking: stack the first buffer pad, the hard substrate, and the adhesive plate on the auxiliary support plate in order, and make the first through holes, the second through holes, and the hard substrate through holes match; c. pin insertion: insert the pin of the conductive pin into the hard substrate through hole, the second through hole, and the first through hole in order after the pin penetrates the adhesive plate; d. second material stacking: stack the soft substrate and the second buffer pad on the adhesive plate in order, and make the soft substrate through hole match the hard substrate through hole, to obtain a combined plate; e. pre-solidification: heat press the combined plate by using a hot press to preliminarily solidify the adhesive plate; f. compression molding: heat press the combined plate by using a compression molding machine to solidify and form the adhesive plate; g. auxiliary material removal: remove the combined plate from the auxiliary support plate, and remove the first buffer pad and the second buffer pad, to obtain a soft and hard combined plate.

2. The method of manufacturing a rigid-flex printed circuit board of claim 1, wherein, In step a, a first hollow groove is cut on the adhesive plate, and in step g, a second hollow groove is cut on the hard substrate to form a soft plate area on the soft and hard combined plate.

3. The method for manufacturing a rigid-flex PCB according to claim 2, characterized in that, In step a, four positioning pins are prepared, and positioning holes are drilled on four sides of the auxiliary support plate, the first buffer pad, the hard substrate, the adhesive plate, the soft substrate, and the second buffer pad; in step b, the positioning pins are inserted into the positioning holes of the auxiliary support plate, and then the first buffer pad, the hard substrate, and the adhesive plate are stacked on the auxiliary support plate in order; in step d, the soft substrate and the second buffer pad are stacked on the adhesive plate in order.

4. The method of manufacturing a rigid-flex printed circuit board of claim 3, wherein, The diameter of the metal cap is 0.25-0.35 mm larger than the diameter of the pin, the thickness of the auxiliary pad plate is greater than the length of the pin, the diameter of the first through hole is 0.08-0.12 mm larger than the diameter of the pin, the diameters of the second through hole and the hard substrate through hole are 0.03-0.08 mm larger than the diameter of the pin, the diameter of the soft substrate through hole is 0.1-0.3 mm smaller than the diameter of the metal cap, and the thickness of the metal cap is within twice the thickness of the adhesive plate.

5. The method of manufacturing a rigid-flex printed circuit board of claim 4, wherein, The adhesive plate is an epoxy resin adhesive film with a thickness of 0.04-0.06 mm.

6. The method of manufacturing a rigid-flex printed circuit board of claim 5, wherein, The first and second cushion pads are TPX or a three-in-one composite film, which comprises, from top to bottom, an upper release film, a cushion layer and a lower release film, wherein the upper and lower release films are one of PET, PA and PP, and the cushion layer is one of PE and PP.

7. The method of manufacturing a rigid-flex printed circuit board of claim 6, wherein, The conductive pins are copper-zinc alloy.

8. The method of manufacturing a rigid-flex printed circuit board of claim 7, wherein, The pre-curing time in step e is 3-5 s, the hot-pressing temperature of the iron is < 150 °C; the hot-pressing temperature of the press in step f is 170-190 °C, and the pressure is 130 bar / cm 2 ~ 170 bar / cm 2 , the pre-pressing time is 30-50 s, and the forming time is 150-300 s.

9. The method of manufacturing a rigid-flex printed circuit board of claim 8, wherein, In step a, the manufacturing steps of the hard substrate include cutting, drilling, copper deposition, electroplating, dry film pasting, exposure and development, etching, AOI, solder mask, surface treatment, electrical testing, final inspection and laser profiling; and the manufacturing steps of the soft substrate include cutting, drilling, copper deposition, electroplating, dry film pasting, exposure and development, etching, AOI, solder mask, surface treatment, electrical testing, final inspection and laser profiling.

10. A rigid-flex printed circuit board, characterized by, The conductive pins comprise a pin and a metal cap connected to the top end of the pin, the bottom end of the pin penetrates through the hard substrate through-hole, and the metal cap is clamped between the soft substrate lower conductor layer and the hard substrate upper conductor layer and realizes the conduction between the soft substrate lower conductor layer and the hard substrate upper conductor layer; the adhesive plate and the hard substrate are respectively hollowed out to form corresponding first and second hollow grooves.

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