Manufacturing method of tin layer surface treatment high-reliability flexible circuit board

Abstract

The invention discloses a manufacturing method of a tin layer surface treatment high-reliability flexible circuit board, and the flexible circuit board is manufactured by adopting a jointed board structure according to design data. The manufacturing method comprises the following steps: manufacturing a jointed board into a flexible core board; printing conductive paste on the flexible core board to form a printed core board; performing reflow soldering on the printed core board, and performing post-process treatment to form a flexible circuit board; the whole scheme is based on a mode of printing solder paste on the surface of the flexible circuit board and carrying out reflow soldering, effective tin layer surface treatment is formed, and a traditional tin spraying processing mode is replaced; based on the design of a board body structure and a positioning hole structure, the use of a first support plate, a second support plate and a matched design structure, the continuous, complete and high-precision processing process of conductive paste is realized, reflow soldering treatment is used, the flexible circuit board with good tin layer surface treatment is formed, the problems of board body deformation, tin pollution, even board body tearing and the like are improved, and the production efficiency is improved. And manual processing is reduced.

Description

Technical Field

[0001] The invention relates to the field of flexible circuit board processing, and in particular to a method for manufacturing a high-reliability flexible circuit board with a tin layer surface treatment. Background Art

[0002] Some circuit boards used in communication products, computers and other products use tin spraying as a surface treatment, which has the advantages of low cost and easy welding. Tin spraying is essentially hot air leveling. Its working principle is to place the board to be processed into a molten tin tank, and then take out the tin tank while using hot air to blow off the excess tin on the surface and in the hole of the printed circuit board. The remaining tin is evenly covered on the pad and the wall of the through hole, forming a surface treatment process.

[0003] If the flexible circuit board needs to be treated with tin spraying, since the board body is relatively soft, the flexible board needs to be fixed on a hard support frame during tin spraying, and then the tin spraying process is carried out together.

[0004] However, when the flexible circuit board is thin or the finished board is required to have high flexibility, the molten tin cylinder and the strong hot air will have a strong impact on the board during tin spraying, causing deformation of the board, tin contamination, and even tearing of the board. If a support plate with a denser skeleton is used for support, then for flexible circuit boards with smaller size and higher tin spraying density, the support plate will be difficult to process in the subsequent forming process after tin spraying, resulting in a greater reliance on manual operation in the processing process and easy damage to the board.

[0005] Based on the above background technology and problems, it is necessary to provide a method for manufacturing a flexible circuit board by forming a tin layer surface treatment instead of tin spraying. Summary of the invention

[0006] The present invention aims at the existing technology for tin spraying processing of flexible circuit boards, which has problems such as board deformation, tin pollution and even board tearing, and the problem of reliance on manual labor and easy damage of the board. A method for manufacturing a high-reliability flexible circuit board with a tin layer surface treatment is provided. The flexible circuit board is manufactured according to design data and adopts a panel structure; the manufacturing method comprises the following steps: S10: forming the assembled panels into a flexible core panel; S20: Printing a conductive paste on the flexible core board to form a printed core board; S30: subjecting the printed core board to reflow soldering and post-processing to form the flexible circuit board.

[0007] Furthermore, the panel is designed with a molding line, the area within the molding line is a valid area, and the other areas are invalid areas. The production of the flexible core board includes: pre-enlarging the invalid area at the edge of the panel to form an auxiliary tool area, and then producing a circuit pattern to form the flexible core board; the circuit pattern includes a first-side solder pad distributed on the first side of the flexible core board, a second-side solder pad on the second side, and a core board through-hole that penetrates the flexible core board.

[0008] Furthermore, the printed conductive paste includes: making a first support pad, fixing the second side of the flexible core board relative to the first support pad, making a first steel mesh, the mesh holes of the first steel mesh corresponding to the through holes of the core board, and the first side pads; printing the conductive paste on the first side to form a single-sided printed core board.

[0009] Furthermore, the first support pad is provided with a first pad groove body, and the first pad groove body corresponds to the distribution of the core plate through holes; the auxiliary tool area is provided with a printing positioning hole, and the first support pad is provided with a hanging nail corresponding to the printing positioning hole, and the fixing is to fix the positioning hole to the hanging nail to fix the flexible core plate.

[0010] Furthermore, the printing of the conductive paste includes: making a second support pad, arranging the first side corresponding to the single-sided printed core board relative to the second support pad, fixing the single-sided printed core board, making a second steel mesh, the mesh of the second steel mesh corresponding to the second-side pad; printing the conductive paste on the second side to form a double-sided printed core board; Furthermore, the second supporting pad is composed of a frame plate and a supporting plate, the frame plate is made with a lattice frame and a lattice through-groove, the lattice frame is distributed corresponding to the auxiliary tool area, the supporting plate corresponds to the lattice through-groove and can be detachably placed in the lattice through-groove, the surface of the supporting plate corresponding to the first surface is made with a pad groove, part of the pad groove corresponds to the first surface welding pad, part of the pad groove corresponds to the core plate through-hole, and the supporting plate is made with pin holes; the surface of the lattice frame is made with a glue layer.

[0011] Furthermore, the support plate is fixed to the table of the printing equipment through the pin hole using pins, the frame frame is put around the support plate, the single-sided printed core board is aligned with the support plate and adhered to the frame frame through the adhesive layer, and the conductive paste is printed through the second steel screen to form a double-sided printed core board.

[0012] Furthermore, the conductive paste is solder paste, and the conductive paste fills the through hole of the core board and covers the first side pad and the second side pad.

[0013] Furthermore, the printed core board is subjected to reflow soldering, including: removing the double-sided printed core board after printing the conductive paste together with the frame frame to form the printed core board, and placing the printed core board in the reflow soldering equipment for heating to form a welded board.

[0014] Furthermore, the post-processing includes: drilling the through holes of the core plate corresponding to the welding plate.

[0015] The technical solution of the present invention is based on the method of printing solder paste on the surface of the flexible circuit board and reflow soldering to form an effective tin layer surface treatment, replacing the traditional tin spraying processing method.

[0016] Furthermore, the board body is first pre-enlarged to provide a basis for subsequent fixing and transfer processing, effectively ensuring that the processing inside the original board body is not affected; by designing a first support pad and printing conductive paste on the first side, the second support pad is further designed and printed conductive paste on the second side, forming a two-sided conductive paste that effectively covers the first side pad and the second side pad, and has the effect of filling the through hole.

[0017] Furthermore, based on the printing of conductive solder on the first side, the second support plate is designed to consist of a support plate and a frame plate, and after printing the conductive paste on the second side, the frame plate and the double-sided printed core board are removed together to form a supporting effect of the frame plate on the flexible board body, and then they are reflowed together to complete the process of effective melting and covering of the solder paste. The first support plate and the second support plate ensure the support of the flexible board body and ensure the continuity of processing.

[0018] Furthermore, for the through holes filled with tin, back drilling or laser ablation is used to form the via holes, thereby improving the processing accuracy of the via holes and ensuring that the plug-in holes can be well used.

[0019] The overall technology forms the basis for the formation of the front process from the design of the board structure and the positioning hole structure for subsequent processing, and uses the first support plate and the second support plate to match the designed structure to achieve a continuous, complete and high-precision processing process of the conductive paste, and then uses reflow soldering and post-processing to form a flexible circuit board with a good tin layer surface treatment, which effectively improves problems such as board deformation, tin contamination and even board tearing. The processing process reduces the degree of manual participation and avoids the occurrence of problems such as easy damage to the board. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0021] Figure 1 The main process flow chart of the embodiment of the present invention is included; Figure 2 This is a schematic diagram of the cross-sectional structure of a flexible core board formed in this embodiment; Figure 3 This is a schematic diagram of the cross-sectional structure of printing the first surface conductive paste in this embodiment; Figure 4 This is a schematic diagram of the cross-sectional structure of printing the second surface conductive paste in this embodiment; Figure 5 This is a schematic diagram of the cross-sectional structure of a disassembled printed core board according to this embodiment; Figure 6 Schematic diagram of the planar structure of the printed core board in this embodiment; Figure 7 is a schematic diagram of the cross-sectional structure of the printed core board after reflow soldering in this embodiment; Figure 8 Schematic diagram of the cross-sectional structure of the flexible circuit board of this embodiment.

[0022] Description of the accompanying drawings: 10, flexible core board; 100, insulating dielectric layer; 1110, molding line; 1120, panel outline; 1210, auxiliary tool area; 1310, first side pad; 1320, second side pad; 1410, core board through hole; 1510, printing positioning hole; 1520, molding positioning hole; 10J, conductive paste; 10D, single-sided printed core board; 20, first steel mesh; 2110, mesh of the first steel mesh; 30, first support pad; 3110, first pad slot; 312 0, hanging nail; 40A, first table; 40B, second table; 410, table pin hole; 40X, pin; 10S, double-sided printed core board; 50, second steel mesh; 5110, mesh of second steel mesh; 60, second supporting pad; 610, frame plate; 610A, frame frame; 610B, frame through groove; 620, supporting plate; 6110, glue layer; 6210, pad groove; 6220, pin hole; 70, printed core board; 80, welding plate; 90, flexible circuit board; 910, through hole.

[0023] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0026] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0028] See also Figure 1 ; Figure 1 The main process flow chart included in the embodiment of the present invention.

[0029] The method for manufacturing a high-reliability flexible circuit board with a tin layer surface treatment according to an embodiment of the present invention comprises: Figure 1 The main production process is described in detail step by step as follows.

[0030] See also Figure 2 ; Figure 2 This is a schematic diagram of the cross-sectional structure of a flexible core board produced in this embodiment.

[0031] Step S10: The panels are assembled to form a flexible core panel 10 .

[0032] In the present embodiment, the panel is designed with a molding line 1110, the area within the molding line 1110 is the effective area, and the other areas are invalid areas, so as to form a flexible core board 10, including: pre-enlarging the invalid area of ​​the board edge of the panel to form an auxiliary tool area 1210, and then making a circuit pattern to form a flexible core board 10; the circuit pattern includes a first-side solder pad 1310 distributed on the first side of the flexible core board 10, and a second-side solder pad 1320 on the second side, and a core board through hole 1410 passing through the flexible core board 10, and the flexible core board 10 includes an insulating medium layer 100.

[0033] The panel is pre-enlarged from the panel outline 1120 of the original panel toward the outside, and all four sides of the panel surface are pre-enlarged for making tool holes such as printing positioning holes 1510 (and other tool graphics used in the processing process).

[0034] During the processing of the flexible circuit board 90, alignment, positioning, electroplating clamping and other processes are required. Therefore, it is necessary to adopt the method of panelization. The edge of the board formed by the panelization is an invalid area, which is used to distribute hole patterns such as forming positioning holes 1520 and tool patterns used for alignment processing. After the final forming process, the invalid area is removed to form a finished flexible circuit board 90.

[0035] In this embodiment, since the single-sided printed core board 10D needs to be adhered to the frame frame 610A later, and the frame frame 610A needs to be removed after processing, at this time, the double-sided printed core board 10S adhered to the frame frame 610A is also removed. Therefore, before making the flexible core board 10, it is necessary to pre-enlarge the panel to reserve the part for subsequent removal while retaining the size it should have; that is, pre-enlargement design is made when designing the data, and when cutting the material, the material is cut according to the pre-enlarged size and processed.

[0036] Optionally, the single-side pre-enlargement size is 100μm to 5mm to ensure supportability and accuracy during processing.

[0037] The flexible core board 10 is manufactured to form pads and through holes for the subsequent printing of the conductive paste 10J. During the actual processing, the first-side pads 1310 and the second-side pads 1320 are generally asymmetrical, so it is necessary to design corresponding support plates 620 on both sides for subsequent processing; wherein the core board through holes 1410 are through holes after electroplating, i.e., conductive holes, and the manufacturing process is “core board drilling → whole board electroplating → manufacturing outer layer graphics”, and the conductive holes can provide an effective attachment hole copper foundation for the subsequent printing of the conductive paste 10J and the melt adhesion of the conductive paste 10J.

[0038] See also Figures 3 to 7 ; Figure 3 This is a schematic diagram of the cross-sectional structure of printing the first surface conductive paste in this embodiment; Figure 4This is a schematic diagram of the cross-sectional structure of printing the second surface conductive paste in this embodiment; Figure 5 This is a schematic diagram of the cross-sectional structure of a disassembled printed core board according to this embodiment; Figure 6 Schematic diagram of the planar structure of the printed core board in this embodiment; Figure 7 Schematic diagram of the cross-sectional structure of the printed core board after reflow soldering according to this embodiment.

[0039] Step S20: The conductive paste 10J is printed on the flexible core board 10 to form a printed core board 70 .

[0040] In this embodiment, printing the conductive paste 10J includes: making a first support pad 30, fixing the second surface of the flexible core board 10 relative to the first support pad 30, making a first steel mesh 20, the mesh 2110 of the first steel mesh corresponds to the core board through hole 1410, and the first side pad 1310; printing the conductive paste 10J on the first side to form a single-sided printed core board 10D (such as Figure 3 as shown).

[0041] Optionally, the thickness of the first supporting pad 30 is 0.5 mm to 3.0 mm.

[0042] Since the flexible core board 10 is made of a flexible material and has no support itself, when printing the conductive paste 10J, a support board 620 is required to support and fix it to provide support for printing.

[0043] This embodiment requires printing the conductive paste 10J into the core board through hole 1410 and the surface of the pad. Therefore, steel screen printing is used in the welding process to achieve the effect of precise positioning and precise printing. Intersecting silk screen printing or screen printing has higher processing accuracy.

[0044] Optionally, the size of the mesh 2110 of the first steel mesh corresponding to the first side pad 1310 is equal to the size of the first side pad 1310, or is 20μm to 30μm larger on one side than the size of the first side pad 1310; the size of the mesh 2110 of the first steel mesh corresponding to the core board through hole 1410 is equal to the size of the hole ring of the core board through hole 1410, or is 20μm to 30μm larger on one side than the size of the hole ring of the core board through hole 1410; if size conditions permit, unilateral pre-enlargement can improve the positioning accuracy and enable the printed conductive paste 10J to cover the pad or the core board through hole 1410.

[0045] In this embodiment, the first support pad 30 is produced with a first pad groove 3110, and the first pad groove 3110 is distributed corresponding to the core plate through hole 1410; the auxiliary tool area 1210 is produced with a printing positioning hole 1510, and the first support pad 30 is produced with a hanging nail 3120 corresponding to the printing positioning hole 1510, and the printing positioning hole 1510 is fixed to the hanging nail 3120 to fix the flexible core plate 10.

[0046] Since printing the conductive paste 10J requires the core board through hole 1410 to be completely filled, it is necessary to ensure the air conduction performance during printing. Therefore, the first support pad 30 needs to be manufactured into a first pad groove 3110 so that the core board through hole 1410 will not have gas blockage problems when printing the conductive paste 10J. Optionally, the first pad groove 3110 can be a through groove or a half groove, and the depth of the half groove is 0.5mm to 2.5mm.

[0047] It is worth noting that if the previous process uses drilling to process the through hole, the pad used for drilling is drilled with a corresponding hole, and the pad after drilling can be used as the first pad slot 3110.

[0048] In this embodiment, printing conductive paste 10J includes: making a second support pad 60, setting the first side corresponding to the single-sided printed core board 10D relative to the second support pad 60, fixing the single-sided printed core board 10D, making a second steel mesh 50, the mesh 5110 of the second steel mesh corresponds to the second side pad 1320; printing the conductive paste 10J on the second side to form a double-sided printed core board 10S.

[0049] Similar to the printing of the first side, the conductive paste 10J is printed on the second side pad 1320 by steel screen printing. Since the core board through hole 1410 has been filled with the conductive paste 10J when printing the first side, the second side does not need to be filled again.

[0050] In the present embodiment, the second support pad 60 is composed of a frame plate 610 and a support plate 620. The frame plate 610 is made with a lattice frame 610A and a lattice through groove 610B. The lattice frame 610A is distributed corresponding to the auxiliary tool area 1210. The support plate 620 corresponds to the lattice through groove 610B and can be detachably placed in the lattice through groove 610B. The surface of the support plate 620 corresponding to the first side is made with a pad groove 6210, part of the pad groove 6210 corresponds to the first side welding pad 1310, and part of the pad groove 6210 corresponds to the core plate through hole 1410. The support plate 620 is made with a pin hole 6220; the surface of the lattice frame 610A is made with a glue layer 6110.

[0051] In this embodiment, printing the conductive paste 10J includes: fixing the support plate 620 on the table of the printing device through the pin hole 6220 using the pin 40X, that is, fixing it to the second table 40B through the table pin hole 410, sleeve the frame frame 610A around the support plate 620, aligning the single-sided printed core board 10D with the support plate 620, optionally aligning through the alignment hole or the alignment target, and adhering to the frame frame 610A through the adhesive layer 6110, printing the conductive paste 10J through the second steel mesh 50, and forming a double-sided printed core board 10S (such as Figure 4 as shown).

[0052] Since the conductive paste 10J has been printed on the first side, when making the second side, it is necessary to prevent the conductive paste 10J on the first side from being smeared, collided, scratched, etc. Therefore, it needs to be taken out vertically and put down vertically during processing, or it can be sucked and placed by automated mechanical equipment, and the second support pad 60 needs to be made with a pad groove 6210 to provide a space for the conductive paste 10J that has been printed on the first side to prevent smearing and other defects.

[0053] In addition to the distribution corresponding to the auxiliary tool area 1210, the lattice frame 610A can also be selected to correspond to the distribution of the invalid area inside the board body if no further special processing is required before subsequent molding. That is, the lattice frame 610A can be set to correspond to the invalid area of ​​the board body to provide stronger support for the board body as a whole, so as to facilitate better support effect during subsequent reflow soldering processing.

[0054] It is worth mentioning that after the conductive paste 10J on the second side is subsequently printed, the double-sided printed core board 10S needs to be removed together with the frame board 610, and the support board 620 needs to be fixed and retained on the second table 40B and not removed. That is, the frame board 610 and the double-sided printed core board 10S are removed and processed together, and the support board 620 can be firmly fixed on the second table 40B by the pins 40X, and the frame board 610 is tightly inserted into the support board 620 and fixed by the support board 620, so that the subsequent frame board 610 is easy to remove but the support board 620 is not removed. Optionally, in order to improve the printing accuracy of the double-sided printed core board 10S, the frame board 610 can also be fixed by pins. After printing is completed, the pins are pulled out and the frame board 610 is removed.

[0055] Optionally, the thickness of the support plate 620 is the same as that of the frame plate 610, which can provide a flat support force and prevent the board surface from being uneven.

[0056] Optionally, the material of the support plate 620 and the thickness of the frame plate 610 can be FR-4 material, aluminum plate, PVC or other supporting materials.

[0057] Optionally, the adhesive layer 6110 is an acrylic adhesive, an epoxy resin adhesive or a polyolefin adhesive. The adhesive layer 6110 can effectively adhere the single-sided printed core board 10D to the frame board 610 to fix the single-sided printed core board 10D. The fusion method (before the lamination process of the multi-layer circuit board) can also be used for hot melt adhesion.

[0058] It is worth noting that when the conductive paste 10J is printed on the first surface, the first support plate 30 also needs to be fixed on the first stage 40A.

[0059] In this embodiment, the conductive paste 10J is solder paste, and the conductive paste 10J fills the core board through hole 1410 and covers the first side pad 1310 and the second side pad 1320 .

[0060] This embodiment prints solder paste on the surface of the flexible circuit board 90 by steel screen printing, and then processes it through reflow soldering equipment to form an effective tin surface covering the pads and the core board through-holes 1410, replacing the conventional tin spraying (hot air leveling) processing method used in the prior art, which is too soft to be tin-sprayed, and causes excessive damage to the board itself, resulting in excessive deformation, tin contamination, and even tearing.

[0061] See also Figure 8 ; Figure 8 Schematic diagram of the cross-sectional structure of the flexible circuit board of this embodiment.

[0062] Step S30: The printed core board 70 is subjected to reflow soldering and post-processing to form a flexible printed circuit board 90 .

[0063] In this embodiment, the printed core board 70 is subjected to reflow soldering, including: removing the double-sided printed core board 10S after printing the conductive paste 10J together with the frame frame 610A (such as Figure 5 As shown), a printed core board 70 is formed, that is, the double-sided printed core board 10S and the frame frame 610A integrally form a printed core board 70 (as shown Figure 6 As shown in FIG. 1 ), the printed core board 70 is placed in a reflow soldering device for heating to form a welded board 80 (as shown in FIG. 1 ). Figure 7 as shown).

[0064] Based on the support and protection of the frame skeleton 610A for the double-sided printed core board 10S, the printed solder paste is heated and melted by the reflow soldering equipment, so that the solder paste is firmly combined with the surface of the first-side solder pad 1310 and the second-side solder pad 1320, and the hole wall and hole ring of the core board through hole 1410, forming a protection for the tin surface (and providing a solderability basis for subsequent soldering components); the heating process parameter curve of the reflow soldering is determined according to the type of solder paste used and the type, quantity and structure of the solder pads of the double-sided printed core board 10S.

[0065] In this embodiment, the post-processing includes: drilling the core plate through hole 1410 corresponding to the welding plate 80 to form a through hole 910 (such as Figure 8 As shown); it also includes molding the printed core board 70 that has been reflow-treated.

[0066] If the core board through hole 1410 has a relatively small diameter and needs to be used as a plug-in hole, the molten solder paste will clog the hole after reflow soldering, and back drilling can be used to open it up to form an effective plug-in hole. It is worth mentioning that since the flexible circuit board 90 is thin, laser ablation can also be used to open up the tin blocking the hole.

[0067] It is worth noting that due to the actual design and processing of circuit boards, the actual structure diagram and the thickness of each layer, line width and other dimensions are all in the micron level. For example, the thickness of each layer is generally 5μm to 50μm. If the drawings in the specification are made according to the actual proportion, there will be a problem of unclear drawings. Therefore, in order to more clearly show the implementation process of the manufacturing method, the drawings of this embodiment are all schematic diagrams that enlarge the technical features, which do not represent the size of the actual structure diagram, nor do they represent enlarged views of the actual structure diagram in proportion.

[0068] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a high-reliability flexible circuit board with a tin layer surface treatment, wherein the flexible circuit board is manufactured according to design data and adopts a panel structure; It is characterized in that The production method comprises the following steps: S10: forming the assembled panels into a flexible core panel; S20: Printing a conductive paste on the flexible core board to form a printed core board; S30: subjecting the printed core board to reflow soldering and post-processing to form the flexible circuit board.

2. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 1, characterized in that: The panel is designed with a molding line, the area within the molding line is a valid area, and the other areas are invalid areas. The production of the flexible core board includes: pre-enlarging the invalid area at the edge of the panel to form an auxiliary tool area, and then producing a circuit pattern to form the flexible core board; the circuit pattern includes a first-side solder pad distributed on the first side of the flexible core board, a second-side solder pad on the second side, and a core board through-hole that penetrates the flexible core board.

3. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 2, characterized in that: The printed conductive paste includes: making a first support pad, fixing the second side of the flexible core board relative to the first support pad, making a first steel mesh, the mesh holes of the first steel mesh corresponding to the core board through holes and the first side pads; printing the conductive paste on the first side to form a single-sided printed core board.

4. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 3, characterized in that: The first support pad is made with a first pad groove body, and the first pad groove body corresponds to the distribution of the core plate through holes; the auxiliary tool area is made with printing positioning holes, and the first support pad is made with hanging nails corresponding to the printing positioning holes, and the fixing is to fix the positioning holes to the hanging nails to fix the flexible core plate.

5. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 4, characterized in that: The printed conductive paste includes: making a second support pad, setting the first side corresponding to the single-sided printed core board relative to the second support pad, fixing the single-sided printed core board, making a second steel mesh, the mesh holes of the second steel mesh corresponding to the second-side pads; printing the conductive paste on the second side to form a double-sided printed core board.

6. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 5, characterized in that: The second supporting pad is composed of a frame plate and a supporting plate. The frame plate is made with a lattice frame and a lattice through-slot. The lattice frame is distributed corresponding to the auxiliary tool area. The supporting plate corresponds to the lattice through-slot and can be detachably placed in the lattice through-slot. The surface of the supporting plate corresponding to the first surface is made with a pad groove. Part of the pad groove corresponds to the first surface welding pad, and part of the pad groove corresponds to the core plate through-hole. The supporting plate is made with pin holes. The surface of the lattice frame is made with a glue layer.

7. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 6, characterized in that: The printed conductive paste includes: using pins to fix the support plate on the table of the printing equipment through the pin holes, sleeve the frame frame around the support plate, align the single-sided printed core board with the support plate, and adhere it to the frame frame through the adhesive layer, and print the conductive paste through the second steel screen to form a double-sided printed core board.

8. The method for manufacturing a high-reliability flexible circuit board with tin layer surface treatment according to any one of claims 3 to 7, characterized in that: The conductive paste is solder paste, which fills the through hole of the core board and covers the first-side pad and the second-side pad.

9. The method for manufacturing a tin layer surface treated high reliability flexible circuit board according to claim 7, characterized in that: The printed core board is subjected to reflow soldering, comprising: removing the double-sided printed core board after printing the conductive paste together with the lattice frame to form the printed core board, and placing the printed core board in the reflow soldering equipment for heating to form a welded board.

10. The method for manufacturing a high-reliability flexible circuit board with tin layer surface treatment according to claim 9, characterized in that: The post-processing includes: drilling the through holes of the core plate corresponding to the welding plate.

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