A soft-hard combined circuit board and its production process

Abstract

The present invention discloses a soft-hard combined circuit board and its production process. It includes a soft board component and a hard board component, the hard board components are respectively fixed on both sides of the soft board component, a heat dissipation through hole 1 and a heat dissipation groove 1 are arranged on the surface of the soft board component, a heat dissipation through hole 2 and a heat dissipation groove 2 are arranged on the surface of the hard board component, the heat dissipation groove 1 and the heat dissipation groove 2 are connected, a heat dissipation fin is fixed on the hard board component, the soft board component is placed on one side of the hard board component, the heat dissipation fin is fixed on the other side of the hard board component, and the heat dissipation fin is located on the heat dissipation groove 2. The beneficial effects of the present invention are: good heat dissipation performance; high precision of the through hole and less drilling dirt generated during drilling; good anti-oxidation and insulation properties; high assembly density; and good guarantee of the hardness of important parts of the soft board component.

Description

Technical Field

[0001] The present invention relates to the technical field related to the processing of a soft-hard combined circuit board, and in particular to a soft-hard combined circuit board and a production process thereof. Background Art

[0002] At present, the technology of printed circuit boards is developing in the direction of multi-layer and multi-functionality. Many printed circuit boards need to be bent multiple times between different planes, which requires the substrate of the printed circuit board to have better flexibility. With the development and improvement of printed circuit technology, rigid-flex boards have emerged. Rigid-flex printed circuit boards include rigid parts and flexible parts. The rigid parts have high flatness and mechanical strength. The flexible parts can achieve dynamic bending, which provides flexibility and freedom for the design of the circuit board. Therefore, rigid-flex printed circuit boards can connect circuits located on different planes, so electronic products often use rigid-flex boards as their parts carriers.

[0003] Since the rigid-flex board has the characteristics of both FPC and PCB, it has the characteristics of high wiring density, light weight, thin thickness and good bending properties. It will inevitably be used in some special cases such as high temperature environments. If the rigid-flex board is to maintain stable operation for a long time, the heat dissipation performance of the circuit board must be improved. Summary of the invention

[0004] The present invention aims to overcome the disadvantage of poor heat dissipation performance in the prior art and provides a rigid-flexible circuit board with good heat dissipation performance and a production process thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A production process for a rigid-flexible circuit board comprises the following steps:

[0007] Step 1: Conduct quality inspection on the rigid board and the flexible board respectively, and select the rigid board and the flexible board that have passed the quality inspection for cutting, cut them into the size required by the design, and then drill corresponding holes on the rigid board and the flexible board respectively;

[0008] Step 2: Align the film to the corresponding hole of the dry film, keep the film pattern overlapped with the board surface, and then transfer the film pattern to the dry film on the board surface;

[0009] Step 3: Develop the dry film in the unexposed area of ​​the circuit pattern, leaving the dry film pattern in the exposed area, and then perform etching treatment on the area where the copper surface is exposed after the circuit pattern is developed, leaving the pattern part covered by the dry film, and perform open and short circuit detection on the processed circuit;

[0010] Step 4: Cover the copper foil circuit of the qualified flexible board with a protective film, and then press the pre-stacked cover film and reinforced flexible board into a whole;

[0011] Step 5, stacking the rigid board, prepreg and flexible board into a rigid-flexible board structure to be pressed and performing a pressing process;

[0012] Step 6: Place the laminated rigid-flex board into a cold storage for freezing for 2 to 4 hours.

[0013] Step 7: Take out the frozen rigid-flex board and pre-press a positioning groove at the location where the via hole needs to be drilled on the board surface;

[0014] Step 8, using a drill to drill a via hole connecting the flexible board and the rigid board on the pre-set positioning groove, and then polishing, grinding and cleaning the via hole;

[0015] Step nine, copper is plated in the cleaned via hole, and the copper in the via hole is thickened;

[0016] Step 10: Paste a layer of photosensitive material on the copper-plated board surface and dissolve all the copper surfaces except the circuit pattern;

[0017] Step 11, covering all circuits and copper surfaces with a solder mask and curing the solder mask;

[0018] Step 12: Mill a flexible window on the rigid-flex board to expose the flexible board part, and mill heat dissipation holes and heat dissipation slots on the surface of the rigid board and the flexible board respectively. Then, attach reinforcement and heat dissipation fins to the corresponding areas of the board surface, and use a probe to test whether there is an open short circuit;

[0019] Step 13: Print the marking symbols on the board surface that has passed the test, and mill the hard-soft board into the target shape;

[0020] Step 14: Conduct a full appearance inspection on the finished products, select defective products, and package the qualified products for storage and shipment.

[0021] Step 1: Conduct incoming material quality inspection on the rigid board and the flexible board respectively. The items of incoming material quality inspection mainly include appearance inspection, size inspection, structure inspection and characteristic inspection of the rigid board and the flexible board to ensure the quality of the rigid board and the flexible board. Select the rigid board and the flexible board that have passed the quality inspection for cutting and cut into the size required by the design. Then, drill corresponding holes on the rigid board and the flexible board respectively to facilitate subsequent processing;

[0022] Step 2: Align the film to the corresponding hole position of the dry film, keep the film pattern overlapped with the board surface, and transfer the film pattern to the dry film on the board surface through the principle of optical imaging;

[0023] Step 3: Develop the dry film in the unexposed area of ​​the circuit pattern, leaving the dry film pattern in the exposed area. Then, the area where the copper surface is exposed after the circuit pattern is developed is etched, leaving the pattern part covered by the dry film. The processed circuit is then tested for open and short circuits. The detection method is automatic optical inspection (AOI), which transmits the image to the equipment for processing through the principle of optical reflection, and compares it with the set data to detect the open and short circuit problems of the circuit.

[0024] Step 4: Cover the copper foil circuit of the qualified flexible board with a protective film, wherein the protective film includes an anti-oxidation film and an electromagnetic protective film to prevent the copper foil circuit from being oxidized by air and shield the influence of external electromagnetic on the rigid-flex board. Then, the pre-stacked covering film and reinforced flexible board are pressed into a whole under high temperature and high pressure;

[0025] Step 5: stack the rigid board, prepreg and flexible board into a rigid-flexible board structure and perform lamination. During lamination, attention should be paid to the consistency of the warp and weft directions of the glass cloth. During the lamination process, attention should be paid to eliminating thermal stress and reducing warping.

[0026] Step 6: Put the pressed hard-flex board into a cold storage for freezing for 2 to 4 hours, so as to reduce the drilling pollution by lowering the temperature of the hard-flex board.

[0027] Step 7: Take out the frozen rigid-flex board and pre-press a positioning groove at the location where the via hole needs to be drilled on the board surface to prevent the drill bit from slipping or deflecting when it contacts the rigid-flex board, thus ensuring the drilling accuracy.

[0028] Step eight, using a drill to drill a via hole connecting the flexible board and the rigid board on the pre-set positioning groove, and polishing and cleaning the via hole, wherein the cleaning method is plasma cleaning, using plasma to achieve an effect that conventional cleaning methods cannot achieve;

[0029] Step nine, copper is plated in the cleaned via hole, and the copper in the via hole is thickened to achieve the effect of conduction;

[0030] Step 10: Paste a layer of photosensitive material on the copper-plated board surface as a film for pattern transfer, and dissolve all the copper surfaces other than the circuit pattern to etch out the required pattern;

[0031] Step 11: Cover all circuits and copper surfaces with a solder mask and cure the solder mask to protect the outer pattern of the rigid-flex board;

[0032] Step 12: Use a laser cutting machine to perform laser cutting to a certain degree on the soft-hard junction line, peel off the hard board part, cut out the flexible window, and mill out heat dissipation holes and heat dissipation grooves on the surface of the rigid board and the flexible board respectively. Then, affix reinforcement and heat dissipation fins to the corresponding areas of the board surface. The cooperation of heat dissipation holes, heat dissipation grooves and heat dissipation fins greatly improves the heat dissipation capacity of the soft-hard combination board, so that the soft-hard combination board can adapt to high temperature environment well. The reinforcement plays a bonding role and increases the hardness of important parts of the flexible board. Use a probe to test whether there is an open short circuit to ensure the product function;

[0033] Step 13: Print marking symbols on the board surface that has passed the test, and mill the hard-flex board into the target shape to facilitate the assembly and identification of subsequent products;

[0034] Step 14: Conduct a full appearance inspection on the finished product to pick out defective products to ensure product quality, and package the qualified products and put them into storage for shipment. Through multiple layers of quality inspection, the quality of the finished product is greatly improved.

[0035] Preferably, in step five, a vacuum press is used to perform hot pressing on the rigid-flexible board, which has a good pressing effect, and a polypropylene film is used as a laminating cushioning material during pressing to improve the lamination quality of the flexible board, which not only ensures its conformability but also relatively reduces the shrinkage and deformation of the pressed parts.

[0036] Preferably, the material of the solder mask layer in step 11 is Sun PSR-4000, which can better meet the requirements of fine-pitch, high-density assembly of flexible boards. It is coated on the board surface by screen printing and quickly dried by infrared drying, with fast drying speed and good effect.

[0037] The present invention also provides a soft-hard combined circuit board, including a soft board component and a hard board component, the hard board components are respectively fixed on both sides of the soft board component, the surface of the soft board component is provided with a heat dissipation through hole 1 and a heat dissipation groove 1, the surface of the hard board component is provided with a heat dissipation through hole 2 and a heat dissipation groove 2, the heat dissipation groove 1 and the heat dissipation groove 2 are connected, the heat dissipation fins are fixed on the hard board component, the soft board component is placed on one side of the hard board component, the heat dissipation fins are fixed on the other side of the hard board component, and the heat dissipation fins are located on the heat dissipation groove 2.

[0038] The hard board components are respectively fixed on both sides of the soft board components, and a heat dissipation through hole 1 and a heat dissipation groove 1 are arranged on the surface of the soft board component, and a heat dissipation through hole 2 and a heat dissipation groove 2 are arranged on the surface of the hard board component, and the heat dissipation groove 1 and the heat dissipation groove 2 are connected. Heat dissipation fins are fixed on the hard board component, and the soft board component is placed on one side of the hard board component, and the heat dissipation fins are fixed on the other side of the hard board component, and the heat dissipation fins are located on the heat dissipation groove 2. Through the cooperation of the heat dissipation through holes, the heat dissipation grooves and the heat dissipation fins, the heat dissipation performance of the soft and hard combination board is greatly improved, so that the soft and hard combination board can adapt well to high temperature environment.

[0039] Preferably, the soft board assembly includes a board 1 and a protective film. The protective film is fixed on both sides of the board 1 and is placed between the board 1 and the hard board assembly. The board 1 is a flexible board. The protective film includes an anti-oxidation film and an electromagnetic protection film to prevent the copper foil circuit from being oxidized by air and to shield the influence of external electromagnetic on the soft and hard board.

[0040] Preferably, the hard board assembly includes board two, a photosensitive layer and a solder resist layer, the soft board assembly is fixed on one side of board two, the photosensitive layer and the solder resist layer are both fixed on the other side of board two, the photosensitive layer is placed between board two and the solder resist layer, board two is a rigid board, the photosensitive layer is used as a film for transferring circuit patterns, and the solder resist layer is used to protect the outer pattern of the hard-soft board. The material of the solder resist layer can be Sun PSR-4000, which can better meet the requirements of fine-pitch, high-density assembly of flexible boards. It is coated on the board surface by screen printing and quickly dried by infrared drying.

[0041] Preferably, a semi-cured layer is coated between the soft board component and the hard board component, and the semi-cured layer is placed between the protective film and the second board. The hard board component is fixed on the soft board component through the semi-cured layer. The semi-cured layer can adopt a low-fluidity P95 semi-fixed sheet. The low fluidity of the glue is of great help to the soft-hard transition area, and will not cause the transition area to need rework or affect the functionality due to overflow of glue.

[0042] Preferably, a conducting hole is provided between the soft board component and the hard board component, and a circuit connecting tube is fixed in the conducting hole, one end of the circuit connecting tube is connected to board one, and the other end of the circuit connecting tube is connected to board two, wherein the circuit connecting tube is a copper tube, which is used to conduct the circuit of board one and the circuit of board two.

[0043] Preferably, a flexible window is provided on the hard board component, a reinforcing plate is provided in the flexible window, and the reinforcing plate is attached to the surface of the soft board component to play a bonding role and increase the hardness of important parts of the soft board component.

[0044] Preferably, a pattern layer is provided on the surface of the hard board assembly, the photosensitive layer is fixed on one side of the solder resist layer, and the pattern layer is fixed on the other side of the solder resist layer, so as to facilitate the assembly and identification of subsequent products.

[0045] The beneficial effects of the present invention are: good heat dissipation performance; high precision of the through hole and less drilling pollution during drilling; good oxidation resistance and insulation; high assembly density; and good guarantee of the hardness of important parts of the soft board component. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a front view of the present invention;

[0047] Figure 2 It is a side view of the present invention.

[0048] In the figure: 1. Soft board component, 2. Hard board component, 3. Board 2, 4. Heat dissipation fins, 5. Heat dissipation groove 2, 6. Heat dissipation hole 2, 7. Pattern layer, 8. Reinforcement board, 9. Board 1, 10. Heat dissipation groove 1, 11. Heat dissipation hole 1, 12. Semi-cured layer, 13. Flexible window, 14. Through hole, 15. Circuit connection tube, 16. Protective film, 17. Photosensitive layer, 18. Solder mask layer. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0050] like Figure 1 and Figure 2 In the embodiment described, a process for producing a rigid-flexible circuit board includes the following steps:

[0051] Step 1: Conduct quality inspection on the rigid board and the flexible board respectively, and select the rigid board and the flexible board that have passed the quality inspection for cutting, cut them into the size required by the design, and then drill corresponding holes on the rigid board and the flexible board respectively;

[0052] Step 2: Align the film to the corresponding hole of the dry film, keep the film pattern overlapped with the board surface, and then transfer the film pattern to the dry film on the board surface;

[0053] Step 3: Develop the dry film in the unexposed area of ​​the circuit pattern, leaving the dry film pattern in the exposed area, and then perform etching treatment on the area where the copper surface is exposed after the circuit pattern is developed, leaving the pattern part covered by the dry film, and perform open and short circuit detection on the processed circuit;

[0054] Step 4: Cover the copper foil circuit of the qualified flexible board with a protective film, and then press the pre-stacked cover film and reinforced flexible board into a whole;

[0055] Step 5, stacking the rigid board, prepreg and flexible board into a rigid-flexible board structure to be pressed and performing a pressing process;

[0056] Step 6: Place the laminated rigid-flex board into a cold storage for freezing for 2 to 4 hours.

[0057] Step 7: Take out the frozen rigid-flex board and pre-press a positioning groove at the location where the via hole needs to be drilled on the board surface;

[0058] Step 8, using a drill to drill a via hole connecting the flexible board and the rigid board on the pre-set positioning groove, and then polishing, grinding and cleaning the via hole;

[0059] Step nine, copper is plated in the cleaned via hole, and the copper in the via hole is thickened;

[0060] Step 10: Paste a layer of photosensitive material on the copper-plated board surface and dissolve all the copper surfaces except the circuit pattern;

[0061] Step 11, covering all circuits and copper surfaces with a solder mask and curing the solder mask;

[0062] Step 12: Mill a flexible window on the rigid-flex board to expose the flexible board part, and mill heat dissipation holes and heat dissipation slots on the surface of the rigid board and the flexible board respectively. Then, attach reinforcement and heat dissipation fins to the corresponding areas of the board surface, and use a probe to test whether there is an open short circuit;

[0063] Step 13: Print the marking symbols on the board surface that has passed the test, and mill the hard-soft board into the target shape;

[0064] Step 14: Conduct a full appearance inspection on the finished products, select defective products, and package the qualified products for storage and shipment.

[0065] In step five, a vacuum press machine is used to heat-press the rigid-flexible board, and a polypropylene film is used as a laminating cushion material during pressing.

[0066] The material of the solder mask layer in step 11 is a thermosetting polyimide material, which is coated on the board surface by screen printing and quickly dried by infrared drying.

[0067] like Figure 1 and Figure 2 As shown, the present invention also provides a soft-hard combined circuit board, including a soft board component 1 and a hard board component 2, the hard board component 2 is respectively fixed on both sides of the soft board component 1, the surface of the soft board component 1 is provided with a heat dissipation through hole 11 and a heat dissipation groove 10, the surface of the hard board component 2 is provided with a heat dissipation hole 26 and a heat dissipation groove 25, the heat dissipation groove 10 is connected to the heat dissipation groove 25, the heat dissipation fin 4 is fixed on the hard board component 2, the soft board component 1 is placed on one side of the hard board component 2, the heat dissipation fin 4 is fixed on the other side of the hard board component 2, and the heat dissipation fin 4 is located on the heat dissipation groove 25.

[0068] The soft board component 1 includes a board 9 and a protective film 16 . The protective film 16 is fixed on both sides of the board 9 . The protective film 16 is placed between the board 9 and the hard board component 2 .

[0069] The hard board component 2 includes board 2 3 , a photosensitive layer 17 and a solder resist layer 18 . The soft board component 1 is fixed on one side of board 2 3 . The photosensitive layer 17 and the solder resist layer 18 are both fixed on the other side of board 2 3 . The photosensitive layer 17 is placed between board 2 3 and the solder resist layer 18 .

[0070] A semi-cured layer 12 is coated between the soft board component 1 and the hard board component 2 . The semi-cured layer 12 is placed between the protective film 16 and the board 2 3 . The hard board component 2 is fixed on the soft board component 1 through the semi-cured layer 12 .

[0071] A conducting hole 14 is provided between the soft board component 1 and the hard board component 2, and a circuit connecting tube 15 is fixed in the conducting hole 14, one end of the circuit connecting tube 15 is connected to the board 1 9, and the other end of the circuit connecting tube 15 is connected to the board 2 3.

[0072] A flexible window 13 is provided on the hard board component 2 , a reinforcing plate 8 is provided in the flexible window 13 , and the reinforcing plate 8 is attached to the surface of the soft board component 1 .

[0073] A pattern layer 7 is disposed on the surface of the hard board assembly 2 , the photosensitive layer 17 is fixed on one side of the solder resist layer 18 , and the pattern layer 7 is fixed on the other side of the solder resist layer 18 .

[0074] Processing:

[0075] First, the flexible substrate and the rigid substrate are processed into the first board 9 and the second board 3 that meet the size specifications by cutting, and corresponding holes are drilled on the first board 9 and the second board 3, and then cleaned and dried.

[0076] Then align the film with the corresponding hole position where the dry film has been pasted, keep the film pattern overlap with the board surface, and transfer the film pattern to the dry film on the board surface through the principle of optical imaging. Develop the dry film in the unexposed area of ​​the circuit pattern, leaving the dry film pattern in the exposed area. Then, the area where the copper surface is exposed after the circuit pattern is developed is corroded, leaving the part of the pattern covered by the dry film, and the processed circuit is tested for open and short circuits.

[0077] After the inspection is completed, the protective film 16 is covered on the qualified board 9, and then the board 9 with the pre-stacked protective film 16 and the reinforcement plate 8 is pressed into a complete soft board assembly 1 under high temperature and high pressure, and then the board 2 3, the semi-cured layer 12 and the soft board assembly 1 are stacked into a soft-hard combination board structure to be pressed and heat-sealed.

[0078] The pressed soft-rigid combination board is placed in a cold storage for freezing for 2 to 4 hours, and then a positioning groove is pre-pressed at the position where the conductive hole 14 needs to be drilled on the board 2 3, and then the conductive hole 14 connecting the board 1 9 and the board 2 3 is drilled on the pre-set positioning groove by a drilling rig, and the conductive hole 14 is polished and plasma cleaned.

[0079] After cleaning, copper is plated in the via hole 14, and the copper in the via hole 14 is thickened. Then, a photosensitive layer 17 is attached to the surface of the copper-plated board 2 3 as a film for pattern transfer, and all copper surfaces other than the circuit pattern are dissolved to etch out the required pattern. Then, all circuits and copper surfaces are covered with a solder resist layer 18 and the solder resist layer 18 is cured to form a hard board component 2.

[0080] Afterwards, a laser cutting machine is used to perform a certain degree of laser cutting on the soft-hard junction line, the hard board part is peeled off, and the flexible window 13 is cut out. Then, a heat dissipation through hole 11 and a heat dissipation groove 10 are milled out on the surface of the soft board component 1, and a heat dissipation through hole 2 6 and a heat dissipation groove 2 5 are milled out on the surface of the hard board component 2. A reinforcement plate 8 is attached to the surface of the soft board component 1, and a heat dissipation fin 4 is fixed on the heat dissipation groove 2 5 of the hard board component 2.

[0081] Finally, the pattern layer 7 is printed on the surface of the soft-hard combination board that has passed the test, and the soft-hard combination board is milled into the target shape. Then the finished product is fully inspected for appearance, defective products are selected, and the qualified good products are packaged and put into storage for shipment.

Claims

1. A production process for a rigid-flexible circuit board, comprising the following steps: Step 1: Conduct quality inspection on the rigid board and the flexible board respectively, and select the rigid board and the flexible board that have passed the quality inspection for cutting, cut them into the size required by the design, and then drill corresponding holes on the rigid board and the flexible board respectively; Step 2: Align the film to the corresponding hole of the dry film, keep the film pattern overlapped with the board surface, and then transfer the film pattern to the dry film on the board surface; Step 3: Develop the dry film in the unexposed area of ​​the circuit pattern, leaving the dry film pattern in the exposed area, and then perform etching treatment on the area where the copper surface is exposed after the circuit pattern is developed, leaving the pattern part covered by the dry film, and perform open and short circuit detection on the processed circuit; Step 4: Cover the copper foil circuit of the qualified flexible board with a protective film, and then press the pre-stacked cover film and reinforced flexible board into a whole; Step 5, stacking the rigid board, the prepreg and the flexible board into a rigid-flexible board structure to be pressed and performing a pressing process; Step 6: Place the laminated rigid-flex board into a cold storage for freezing for 2 to 4 hours. Step 7: Take out the frozen rigid-flex board and pre-press a positioning groove at the location where the via hole needs to be drilled on the board surface; Step 8: Drilling a via hole connecting the flexible board and the rigid board on the pre-set positioning groove using a drill, and polishing, grinding and cleaning the via hole; Step nine, copper is plated in the cleaned via hole, and the copper in the via hole is thickened; Step 10: Paste a layer of photosensitive material on the copper-plated board surface and dissolve all the copper surfaces except the circuit pattern; Step 11, covering all circuits and copper surfaces with a solder mask and curing the solder mask; Step 12: Mill a flexible window on the rigid-flex board to expose the flexible board part, and mill heat dissipation holes and heat dissipation slots on the surface of the rigid board and the flexible board respectively. Then, attach reinforcement and heat dissipation fins to the corresponding areas of the board surface, and use a probe to test whether there is an open short circuit; Step 13: Print the marking symbols on the board surface that has passed the test, and mill the hard-soft board into the target shape; Step 14: Conduct a full appearance inspection on the finished products, select defective products, and package the qualified products for storage and shipment; A fully inspected and qualified soft-hard combination circuit board comprises a soft board component (1) and a hard board component (2), wherein the hard board component (2) is respectively fixed on two sides of the soft board component (1), a heat dissipation through hole (11) and a heat dissipation groove (10) are arranged on the surface of the soft board component (1), a heat dissipation through hole (6) and a heat dissipation groove (5) are arranged on the surface of the hard board component (2), the heat dissipation groove (10) and the heat dissipation groove (5) are connected, a heat dissipation fin (4) is fixed on the hard board component (2), the soft board component (1) is placed on one side of the hard board component (2), and the heat dissipation fin (4) is fixed on the hard board component (2). On the other side, the heat dissipation fin (4) is located on the heat dissipation groove 2 (5), the soft board component (1) comprises a board 1 (9) and a protective film (16), the protective film (16) is fixed on both sides of the board 1 (9), the protective film (16) is placed between the board 1 (9) and the hard board component (2), the hard board component (2) comprises a board 2 (3), a photosensitive layer (17) and a solder resist layer (18), the soft board component (1) is fixed on one side of the board 2 (3), the photosensitive layer (17) and the solder resist layer (18) are both fixed on the other side of the board 2 (3), and the photosensitive layer (17) is placed between the board 2 (3) and the solder resist layer (18).

2. A process for producing a rigid-flexible circuit board according to claim 1, characterized in that: In step five, a vacuum press machine is used to heat-press the rigid-flexible board, and a polypropylene film is used as a laminating cushion material during pressing.

3. The process for producing a rigid-flexible circuit board according to claim 1, characterized in that: The material of the solder mask layer in step 11 is a thermosetting polyimide material, which is coated on the board surface by screen printing and quickly dried by infrared drying.

4. A fully qualified soft and hard combination circuit board manufactured by the soft and hard combination circuit board production process according to claim 1, characterized in that: A semi-cured layer (12) is coated between the soft board component (1) and the hard board component (2); the semi-cured layer (12) is placed between the protective film (16) and the second board (3); and the hard board component (2) is fixed to the soft board component (1) via the semi-cured layer (12).

5. A fully qualified soft and hard combination circuit board manufactured by the soft and hard combination circuit board production process according to claim 1, characterized in that: A conducting hole (14) is provided between the soft board component (1) and the hard board component (2), a circuit connecting tube (15) is fixed in the conducting hole (14), one end of the circuit connecting tube (15) is connected to the first board (9), and the other end of the circuit connecting tube (15) is connected to the second board (3).

6. A fully qualified soft-hard combination circuit board manufactured by the soft-hard combination circuit board production process according to claim 1, characterized in that: A flexible window (13) is provided on the hard board component (2), a reinforcing plate (8) is provided in the flexible window (13), and the reinforcing plate (8) is attached to the surface of the soft board component (1).

7. A fully qualified soft and hard combination circuit board manufactured by the soft and hard combination circuit board production process according to claim 1, characterized in that: A pattern layer (7) is provided on the surface of the hard board component (2), the photosensitive layer (17) is fixed on one side of the solder resist layer (18), and the pattern layer (7) is fixed on the other side of the solder resist layer (18).

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