Method for manufacturing rigid-flex printed circuit board with crossed surface flexible layer

Abstract

The invention discloses a method for manufacturing a rigid-flex printed circuit board with a crossed surface flexible layer, which comprises the following steps of: taking a double-sided flexible copper-clad plate, manufacturing a copper layer and an insulating medium layer on one surface of the double-sided flexible copper-clad plate to form a groove body, forming an etching and ablation groove, distributing the groove body corresponding to the edge of a flexible board area, attaching a cover film in the range of the groove body, and forming an upper flexible board and a lower flexible board, manufacturing a rigid core plate layer and prepregs, stacking and laminating to form a laminated plate, manufacturing an outer layer circuit pattern, and then forming to form the rigid-flexible combined plate; optionally, a windowing rigid core plate and a windowing prepreg are manufactured, one layer of flexible plate is stacked and pre-pressed to form a groove body structure, a release pad is arranged in the groove body, and the other layer of flexible plate is stacked and pressed to form a pressed plate; the etching and ablating groove is formed in the flexible plate, it is guaranteed that the problem that the flexible plate is difficult to mill during forming is solved, the mode that the release pad is arranged is selectively adopted to replace the mode that the flexible plate is broken off after depth-controlled milling, and the machining quality and precision of the plate body are effectively improved.

Description

Technical Field

[0001] The invention relates to the field of manufacturing circuit boards and rigid-flex boards, and in particular to a method for manufacturing a rigid-flex board with a cross-type surface flexible layer. Background Art

[0002] For some more complex electronic modules, more and stronger functions are required to be realized in a limited space. Therefore, their circuit boards generally use rigid-flex boards to meet the conditions for supporting and three-dimensional installation of electronic components.

[0003] Control modules such as smart lighting systems for intelligent connected vehicles are required to have more complex functions. Therefore, more complex design and processing technologies are also proposed for rigid-flexible boards. Some rigid-flexible boards are designed to have flexible board layers on the upper and lower surfaces of the board, and the flexible boards are in a cross-shaped structure.

[0004] At present, for this type of rigid-flexible board, there is a great difficulty in how to remove the unnecessary middle layer after the layers are pressed together to form a laminate, so as to form a flexible board area. The industry generally adopts a method of making a controlled depth groove at the rigid board layer that needs to be removed at the rigid-flexible combination position, and then breaking the rigid board layer at this position after molding.

[0005] However, the above method has the problem that if the rigid board layer extends into the rigid board area due to expansion and contraction during lamination, or the depth control groove is filled with the pressed resin, the subsequent rigid board layer may be difficult to break, affecting the processing quality and efficiency, and may even cause the board to be delaminated and scrapped.

[0006] In view of the above background and problems, it is necessary to provide an effective method for manufacturing a rigid-flexible board with a cross-surface flexible layer. Summary of the invention

[0007] The present invention aims to provide a method for manufacturing a rigid-flexible board with a cross-surface flexible layer, in order to solve the problem that the middle layer of the rigid board present during the processing is difficult to remove, which easily causes the board body to be delaminated, etc., the rigid-flexible board includes a rigid board area and a flexible board area, the combination position of the rigid board area and the flexible board area is a rigid-flexible combination position, the flexible board area includes an upper flexible board area and a lower flexible board area, the upper and lower surface layers of the rigid board area are respectively the combination layers of the upper flexible board area and the lower flexible board area with the rigid board area; the rigid-flexible board during the processing is provided with a molding line, the area within the molding line range is the effective area, and the area outside the range is the auxiliary area.

[0008] The production method comprises the following steps: S10: Take a double-sided flexible copper-clad laminate, make an etching pattern on one of the copper layers, and laser ablate the exposed insulating dielectric layer corresponding to the etching pattern to form an etching ablation groove; the etching ablation groove corresponds to the edge distribution of the upper flexible board area that is not combined with the rigid board area, and corresponds to the rigid-flexible combination position distribution of the lower flexible board area; attach a covering film to the upper and lower surfaces of the double-sided flexible copper-clad laminate corresponding to the upper flexible board area within the etching ablation groove range; and form an upper flexible board through overall processing; The lower flexible board is manufactured by the same manufacturing method as the upper flexible board; S20: Take a rigid copper clad board, make a rigid board circuit pattern, and form a rigid core board; and take a prepreg, align and stack the upper flexible board, the rigid core board, and the lower flexible board in sequence, and set the prepreg between the upper flexible board and the rigid core board, and between the rigid core board and the lower flexible board; the etching and ablation grooves of the upper flexible board are arranged opposite to the etching and ablation grooves of the lower flexible board; and then press them together to form a pressed board; S30: manufacturing an outer circuit pattern of the surface layer of the laminated board, wherein the outer circuit pattern includes an etching pattern of the surface copper layer corresponding to the etching and ablation groove; and then performing molding processing according to the molding line pair to form a rigid-flexible board with a cross-type surface flexible layer.

[0009] Further, forming the pressed plate comprises: S210: Making a first through window on the rigid core board to form a windowed rigid core board; making a second through window on the prepreg to form a windowed semipreg; aligning and stacking the upper flexible board or the lower flexible board with the windowed rigid core board in sequence, and setting the windowed semipreg between the upper flexible board or the lower flexible board and the windowed rigid core board, and on the surface of the windowed rigid core board; the etching and ablation groove of the upper flexible board or the lower flexible board is set toward the windowed rigid core board; the coverage range of the first through window and the second through window includes the range of the flexible board area; and then pre-pressing is performed, and the first through window and the second through window form a pre-pressed window groove; S220: a release pad is arranged in the pre-pressed window groove, and the lower flexible board or the upper flexible board is aligned and stacked on one side of the release pad, and then pressed together to form the pressed board.

[0010] Furthermore, an edge groove is made at the edge of the release pad adjacent to the rigid-flex combination position, and after the release pad is set, glue is dispensed into the edge groove, and the glue is filled with release agent.

[0011] Furthermore, the release agent is a PTFE release agent with a viscosity of 350 dPa·s to 900 dPa·s.

[0012] Furthermore, the size of one side of the release pad is smaller than or equal to the size of the pre-pressed window opening groove.

[0013] Furthermore, the release pad is made of PTFE, PI, TPX, ETFE or silicone.

[0014] Furthermore, the groove body of the pre-stressed window groove within the range of the flexible board area is the groove body main body; the pre-stressed window groove is also provided with an auxiliary groove body extending from the groove body main body to the auxiliary area; the auxiliary groove body is a protruding groove body structure that is greater than or equal to a quadrilateral and is connected to the groove body main body; the release pad is provided with an auxiliary fixing area corresponding to the auxiliary groove body structure.

[0015] Furthermore, the pre-pressing is performed at a temperature of 140° C. to 180° C., using a pressure of 15 kg / cm² to 25 kg / cm², for 2 minutes to 10 minutes.

[0016] Optionally, forming the laminate comprises: S210A: The prepreg layer is arranged on the upper and lower surfaces of the rigid core board, and pre-pressed to form a pre-pressed core board; according to the molding line, a through groove is made at the edge position of the rigid board area of ​​the pre-pressed core board corresponding to the rigid-flex combination position to form a pre-cut groove; the pre-pressed core board is processed to form a pre-cut groove core board; S220A: Align and stack the upper flexible board, the pre-grooved core board, and the lower flexible board in sequence, and then press them together to form the pressed board.

[0017] Optionally, the through groove is made by milling, or by laser ablation of the insulating medium layer combined with etching of the copper layer.

[0018] The technical solution of the present invention firstly makes an etching and ablation groove on the flexible board layer to form a flexible board opening effect during the final processing, and uses the opening of windows in each layer of the rigid board layer to make a pre-pressed plate. Further, a release pad is set, and an auxiliary fixing area and a filling release agent are set, which effectively improves the setting accuracy and processability of the release pad, and replaces the existing technology of using a controlled depth groove body to the position of the rigid-flexible combination position and then breaking the rigid board, so that the processing process is more operable, reduces the influence of errors in the processing process on the processing itself, and improves the quality and reliability of the processing; further, laser ablation is combined with etching of the copper layer to make a pre-cut groove at the edge of the rigid board at the rigid-flexible combination position, improves the processing accuracy of the pre-cut groove, facilitates the pre-cut groove to form a carbonized inert groove inner wall, prevents the groove body from being closed during the pressing process, and combines the etching and ablation groove of the flexible board layer. After subsequent molding, the rigid board layer can be conveniently removed; the overall manufacturing method forms a process of coordinated processing of the flexible board layer and the rigid board layer, forming an effective overall processing flow, which can effectively improve the processing quality and processing accuracy of the rigid-flexible combination board with the cross-surface flexible layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 The key process flow chart included in the embodiment of the present invention; Figure 2 This is a schematic diagram of the planar structure of the upper flexible board formed in this embodiment; Figure 3 for Figure 2 AA cross-sectional structure schematic diagram; Figure 4 A key process flow chart for forming a pressed plate for an embodiment of the present invention; Figure 5 A schematic diagram of a cross-sectional structure of a stacked structure formed in accordance with an embodiment of the present invention; Figure 6 This is a schematic diagram of the cross-sectional structure of a pre-pressing plate formed in an embodiment of the present invention; Figure 7 A schematic diagram of the cross-sectional structure of a release pad pre-pressing plate produced in accordance with an embodiment of the present invention; Figure 8 for Figure 7 Schematic diagram of BB cross-section structure; Fig. 9A schematic diagram of the cross-sectional structure of a release pad pre-pressing plate having an auxiliary fixing area manufactured in accordance with an embodiment of the present invention; Fig.10 A schematic diagram of the cross-sectional structure of a pressed plate produced in an embodiment of the present invention; Fig.11 A key process flow chart for forming another press plate according to an embodiment of the present invention; Fig.12 A schematic diagram of the planar structure of a pre-grooved core plate produced in accordance with an embodiment of the present invention; Fig.13 for Fig.12 Schematic diagram of CC cross-section structure; Fig.14 A schematic diagram of the cross-sectional structure of another type of pressed plate produced by an embodiment of the present invention; Fig.15 A schematic diagram of the planar structure of a rigid-flex board with a cross-type surface flexible layer manufactured in accordance with an embodiment of the present invention; Fig.16 for Fig.15 Schematic diagram of DD cross-section structure; Fig.17 for Fig.15 Schematic diagram of the EE cross-sectional structure.

[0021] Description of Figure Numbers:

[0022] 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

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] See also Figure 1 , Figure 1 The present invention is a key process flow chart included in the implementation mode of the present invention.

[0028] A method for manufacturing a rigid-flexible board according to an embodiment of the present invention comprises: Figure 1 The key production process is described in detail step by step as follows.

[0029] See also Figure 2 and Figure 3 ; Figure 2 This is a schematic diagram of the planar structure of the upper flexible board formed in this embodiment; Figure 3 for Figure 2 Schematic diagram of the AA cross-section structure.

[0030] The present embodiment provides a method for manufacturing a rigid-flexible board 60 with a cross-surface flexible layer, wherein the rigid-flexible board 60 includes a rigid board area 10G and a flexible board area 10R, wherein the combination position of the rigid board area 10G and the flexible board area 10R is a rigid-flexible combination position, wherein the flexible board area 10R includes an upper flexible board area 10RS and a lower flexible board area 10RX, wherein the upper and lower surface layers of the rigid board area 10G are respectively the combination layers of the upper flexible board area 10RS and the lower flexible board area 10RX with the rigid board area 10G; the rigid-flexible board during the processing is provided with a molding line 10C, wherein the area within the molding line 10C is an effective area, and the area outside the molding line 10C is an auxiliary area.

[0031] The production method comprises the following steps: Step S10: Take a double-sided flexible copper-clad laminate, make an etching pattern on one of the copper layers, and laser ablate the insulating dielectric layer exposed corresponding to the etching pattern to form an etching ablation groove 110; the etching ablation groove 110 corresponds to the edge distribution of the upper flexible board area 10RS that is not combined with the rigid board area 10G, and corresponds to the rigid-flexible combination position distribution of the lower flexible board area 10RX; attach a covering film 120 to the upper and lower surfaces of the double-sided flexible copper-clad laminate corresponding to the upper flexible board area 10RS within the range of the etching ablation groove 110; and form an upper flexible board 10 (such as Figure 2 and Figure 3 As shown), the covering film is a first covering film 120. Preferably, the covering film extends into the rigid board area by a distance of 20 μm to 200 μm, which can ensure that the covering film is firmly pressed into the interior of the rigid board area to form an effective rigid-flex bonding effect.

[0032] The lower flexible board 20 is manufactured by the same manufacturing method as the upper flexible board; that is, another double-sided flexible copper-clad board is taken, an etching pattern is made on one copper layer, and the insulating dielectric layer exposed corresponding to the etching pattern is laser ablated to form another etching ablation groove 210 (not marked in the figure); the other etching ablation groove 210 corresponds to the edge distribution of the lower flexible board area 10RS not combined with the rigid board area 10G; another covering film 220 (such as 220) is attached to the upper and lower surfaces of the other double-sided flexible copper-clad board corresponding to the lower flexible board area 10RS within the range of the other etching ablation groove 210. Figure 5 As shown); the lower flexible plate 20 is formed by integral processing.

[0033] In this embodiment, etching and ablation grooves are first made for the copper layer and the insulating dielectric layer on one side of the flexible board (i.e., the upper flexible board and the lower flexible board). The copper layer on one side is retained at the position of the groove body. Since the position corresponding to the groove body is the outline of the flexible board area 10R and the rigid-flexible combination position of the flexible board on the opposite side, the position of the etching and ablation groove does not form a pressed structure with other layers during lamination. On the other hand, when the flexible board at the position of the etching and ablation groove is subsequently formed, it is only necessary to etch away the copper layer on the surface by etching, without the need for laser ablation, controlled depth milling and other processing methods, thereby effectively improving the processing efficiency and processing accuracy.

[0034] Since the flexible board is on the surface layer, and the rigid-flexible combination of the flexible board on the opposite side needs to be "cut off" at the end to take out the internal rigid board layer, it is necessary to make an etching ablation groove in advance for the flexible board layer at the rigid-flexible combination of the flexible board on the opposite side.

[0035] Step S20: Take a rigid copper clad laminate, make a rigid board circuit pattern, and form a rigid core board; and take a semi-cured sheet; align and stack the upper flexible board 10, the rigid core board, and the lower flexible board 20 in sequence, and set the semi-cured sheet between the upper flexible board 10 and the rigid core board, and between the rigid core board and the lower flexible board 20; the etching and ablation grooves 110 of the upper flexible board 10 and the etching and ablation grooves 210 of the lower flexible board 20 are arranged oppositely; and then press them together to form a pressed board.

[0036] See also Figure 4 ; Figure 4 A key process flow chart for forming a pressed plate according to an embodiment of the present invention.

[0037] In one embodiment, a method of making a laminated sheet includes: Figure 4 The key production process.

[0038] See also Figures 5 to 10 ; Figure 5 A schematic diagram of a cross-sectional structure of a stacked structure formed in accordance with an embodiment of the present invention; Figure 6 This is a schematic diagram of the cross-sectional structure of a pre-pressing plate formed in an embodiment of the present invention; Figure 7 A schematic diagram of the cross-sectional structure of a release pad pre-pressing plate produced in accordance with an embodiment of the present invention; Figure 8 for Figure 7 Schematic diagram of BB cross-section structure; Fig. 9 A schematic diagram of the cross-sectional structure of a release pad pre-pressing plate having an auxiliary fixing area manufactured in accordance with an embodiment of the present invention; Fig.10 It is a schematic diagram of the cross-sectional structure of a pressed plate made according to an embodiment of the present invention.

[0039] Forming a laminate includes: Step S210: A first through window 3110 is made on the rigid core board to form a windowed rigid core board 310; a second through window 3210 is made on the prepreg to form a windowed prepreg 320; the upper flexible board 10 or the lower flexible board 20 and the windowed rigid core board 310 are aligned and stacked in sequence, and the windowed prepreg 320 is arranged between the upper flexible board 10 or the lower flexible board 20 and the windowed rigid core board 310, and on the surface of the windowed rigid core board 310; the core layer stacking structure 30 (such as Figure 5 The etching groove 110 (or another etching groove 210) of the upper flexible board 10 or the lower flexible board 20 is arranged toward the window rigid core board 310; the coverage of the first through window 3110 and the second through window 3210 includes the range of the flexible board area 10R. Then, pre-pressing is performed to form a pre-pressed board 40 (as shown in FIG. Figure 6As shown); the first through window 3110 and the second through window 3210 form a pre-pressed window opening groove 410.

[0040] Step S220: A release pad 420 is arranged in the pre-pressed window groove 410 to form a release pad pre-pressed plate 40A (such as Figure 7 and Figure 8 As shown), the lower flexible board 10RX or the upper flexible board 10RS is aligned and stacked on one side of the release pad 420; and then pressed together to form the pressed board 50.

[0041] In this embodiment, a manufacturing method is adopted in which windows are firstly opened in each layer of the rigid core board layer, and then pre-pressed with one layer of the flexible board, and then a release pad 420 is arranged in the formed pre-pressed window groove 410. The release pad 420 is used to fill and release the groove body during the pressing process of the board body. The release pad 420 has good conformation during the pressing process and release ability after the processing is completed, and can form an effective auxiliary processing function. Compared with the processing method of first controlling the depth of the rigid core board and then breaking it off, it has better operability and prevents the part that needs to be broken off from being pressed into the interior of the rigid board, causing the problem of difficulty in breaking it off or damaging the board body.

[0042] Furthermore, the size of one side of the release pad 420 is smaller than or equal to the size of the pre-pressed window groove 410 ; further, the material of the release pad 420 is PTFE, PI, TPX, ETFE or silicone.

[0043] Since the rigid board material and the flexible board material have certain expansion and contraction properties during the lamination process, the size of the release pad 420 needs to be smaller than the size of the pre-pressed window groove 410 to provide sufficient space for the material to flow and fill with glue.

[0044] Furthermore, an edge groove is formed at the edge of the release pad adjacent to the rigid-flex combination position. After the release pad 420 is provided, glue is dispensed into the edge groove. The glue is dispensed to fill the release agent 430 (such as Figure 7 and Figure 8 As shown); further, the release agent 430 is a PTFE type release agent with a viscosity of 350 dPa·s to 900 dPa·s.

[0045] Since the flexible board layer of the rigid-flexible board prepared in this embodiment is located in the surface layer, another key processing position is the rigid-flexible combination position. Since the release pad has a certain rigidity and there is a certain alignment error in the process of setting the release pad, it may cause the rigid-flexible combination position to have problems such as depression and protrusion due to glue flow and filling during lamination, resulting in difficulty in subsequent processing. Therefore, in this embodiment, a release pad is used to make way for the rigid-flexible combination position, and the release agent 430 is filled into the edge groove formed by the making way. The release agent 430 is softer, softer, and more plastic than the release pad 420, so as to improve the cushioning property of the rigid-flexible combination position against glue flow and filling during the lamination process, thereby improving the flatness of the surface of the laminated board.

[0046] Furthermore, the groove body of the pre-pressed window groove 410 within the range of the flexible board area is the groove body; the pre-pressed window groove 410 is also provided with an auxiliary groove body extending from the groove body to the auxiliary area; the auxiliary groove body is a protruding groove body structure greater than or equal to a quadrilateral connected to the groove body; the release pad 420 is provided with an auxiliary fixing area 420F (such as Fig. 9 as shown).

[0047] In order to further improve the positioning accuracy of the release pad 420, the pre-pressed window groove 410 and the corresponding release pad 420 are extended to the auxiliary area. Because the auxiliary area will eventually be cut off during the molding process, the size of the extended release pad 420 can be the same as the extended pre-pressed window groove 410, that is, without unilateral reduction, the release pad 420 in the extended position is "stuck" in the pre-pressed window groove 410 to form an effective fixing effect; if it is set like this, a bulge will appear on the board surface after pressing, so the auxiliary fixing area 420F should not be too close to the rigid board area and the flexible board area, generally more than 200μm apart, to ensure that the board surface bulge generated during pressing in this area will not affect the processing effect of the effective area.

[0048] It is worth mentioning that in order to improve the positioning accuracy of the release pad 420, an adhesive layer can be set in the auxiliary area outside the effective area (i.e., the rigid board area and the flexible board area) corresponding to the surface of the release pad 420. Epoxy resin glue or acrylic glue can be used to effectively and firmly adhere the release pad 420 to the bottom of the pre-pressed window groove 410, further ensuring the accuracy of the release pad 420 during positioning and preventing problems such as slippage and offset from occurring during the pressing process.

[0049] Furthermore, the pre-pressing is performed at a temperature of 140° C. to 180° C., using a pressure of 15 kg / cm² to 25 kg / cm², for 2 minutes to 10 minutes.

[0050] Since the whole board needs to be pressed later, a pre-pressing method is adopted here, that is, under the condition that the Tg value temperature of the rigid board insulating medium layer and the semi-cured sheet is reached, a relatively small pressure is used and the pressing time is relatively short, so that the pre-pressed board forms a preliminary pressed state, which meets the prerequisite of the overall structure of subsequent processing, prevents excessive glue flow caused by excessive pressing, causes deformation of the pre-pressed window groove 410, and prevents excessive expansion and contraction during the subsequent secondary pressing.

[0051] See also Fig.11 ; Fig.11 A key process flow chart for forming another type of pressed plate according to an embodiment of the present invention.

[0052] In another embodiment, a method of making another laminated sheet includes: Fig.10 The key production process.

[0053] See also Figure 12 to Figure 14 ; Fig.12 A schematic diagram of the planar structure of a pre-grooved core plate produced in accordance with an embodiment of the present invention; Fig.13 for Fig.12 Schematic diagram of CC cross-section structure; Fig.14 It is a schematic diagram of the cross-sectional structure of another type of pressed plate made according to an embodiment of the present invention.

[0054] Another method of forming a laminate includes: Step S210A: The semi-cured sheet layer is arranged on the upper and lower surfaces of the rigid core board, and pre-pressed to form a pre-pressed core board; according to the molding line 10C, a through groove is made at the edge position of the rigid board area 10G of the pre-pressed core board corresponding to the rigid-flexible combination position to form a pre-cut groove 410X; the pre-pressed core board is processed to form a pre-cut groove core board 40X (such as Fig.12 and Fig.13 as shown).

[0055] Step S220A: The upper flexible board 10RX, the pre-cut core board 40X, and the lower flexible board 10RS are aligned and stacked in sequence, and then pressed together to form another pressed board 50X (such as Fig.14 as shown).

[0056] In this embodiment, a rigid core board without a flexible board is pre-pressed to form an integral rigid core board, and then a pre-cut groove 410X structure is made at the rigid-flexible combination position with reference to the rigid board area, and then pressed together with the upper flexible board 10 and the lower flexible board 20 to form a whole; this processing method is simpler and can form an effective removable rigid core board layer, but compared with the processing method of setting a release pad 420, this method has lower processing accuracy, because the production of the pre-cut groove 410X needs to ensure that the groove body has a certain width, so that the groove body will not be pressed closed during the pressing process, resulting in problems such as pressing into the rigid board area or subsequent difficulty in peeling, and the width of the pre-cut groove 410X is likely to cause the problem of depression in the board surface during pressing, resulting in greater difficulty in subsequent surface circuit production; therefore, this method is generally suitable for processing conditions with relatively low precision requirements (for example: the width of the circuit is large, the gap between the circuits is wide, and the thickness of the flexible board layer is thick).

[0057] Furthermore, the through groove is made by milling, or by laser ablation of the insulating medium layer combined with etching of the copper layer.

[0058] The manufacturing method is laser ablation of the insulating dielectric layer combined with etching of the copper layer. The laser ablation has higher precision, and a highly inert carbon black layer is formed on the edge of the slot after ablation, which helps to prevent the slot from being pressed and closed.

[0059] See also Figures 15 to 17 ; Fig.15 A schematic diagram of the planar structure of a rigid-flex board with a cross-type surface flexible layer manufactured in accordance with an embodiment of the present invention; Fig.16 for Fig.15 Schematic diagram of DD cross-section structure; Fig.17 for Fig.15 Schematic diagram of the EE cross-sectional structure.

[0060] After the above processing, a pressed plate 50 or another pressed plate 50X is manufactured, and further processed by the following processing steps; take the pressed plate 50 as an example.

[0061] Step S30: The outer circuit pattern of the surface layer is formed on the laminated board 50, and the outer circuit pattern includes the etching pattern of the surface copper layer corresponding to the etching and ablation groove 110; then, the molding process is performed according to the molding line 10C to form the cross-type surface flexible layer rigid-flexible board 60 (such as Figures 15 to 17 as shown).

[0062] Since only the copper layer remains on the surfaces of the etched and ablated grooves of the upper flexible board 10 and the lower flexible board 20 , the copper layer can be removed by etching, thereby improving the processing accuracy of the board body.

[0063] 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.

[0064] 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 rigid-flexible board with a cross-surface flexible layer, characterized in that: The rigid-flexible board comprises a rigid board area and a flexible board area, the combination position of the rigid board area and the flexible board area is a rigid-flexible combination position, the flexible board area comprises an upper flexible board area and a lower flexible board area, and the upper and lower surface layers of the rigid board area are respectively the combination layers of the upper flexible board area and the lower flexible board area with the rigid board area; The rigid-flex board during processing is provided with a forming line, the area within the forming line is an effective area, and the area outside the range is an auxiliary area; The production method comprises the following steps: S10: Take a double-sided flexible copper-clad board, make an etching pattern on one of the copper layers, and laser ablate the insulating dielectric layer exposed corresponding to the etching pattern to form an etching ablation groove; The etched ablation grooves correspond to the edge distribution of the upper flexible board area that is not combined with the rigid board area, and correspond to the rigid-flexible combination position distribution of the lower flexible board area; Attaching covering films to the upper and lower surfaces of the double-sided flexible copper-clad laminate corresponding to the upper flexible board area within the range of the etching and ablation groove; The upper flexible plate is formed by integral processing; The lower flexible board is manufactured by the same manufacturing method as the upper flexible board; S20: Take a rigid copper clad board, make a rigid board circuit pattern, and form a rigid core board; and taking a prepreg, aligning and stacking the upper flexible board, the rigid core board, and the lower flexible board in sequence, and placing the prepreg between the upper flexible board and the rigid core board, and between the rigid core board and the lower flexible board; The etching and ablation groove of the upper flexible board is arranged opposite to the etching and ablation groove of the lower flexible board; Then press together to form a pressed board; S30: manufacturing an outer circuit pattern of a surface layer of the laminate, wherein the outer circuit pattern includes an etching pattern of a surface copper layer corresponding to the etching and ablation groove; Then, the molding process is performed according to the molding line pair to form the rigid-flexible board with the cross-surface flexible layer.

2. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer according to claim 1, characterized in that: The forming of the pressed plate comprises: S210: making a first through window on the rigid core board to form a windowed rigid core board; Making a second through window on the prepreg to form a windowed prepreg; Align and stack the upper flexible board or the lower flexible board with the window opening rigid core board in sequence, and arrange the window opening prepreg between the upper flexible board or the lower flexible board and the window opening rigid core board, and on the surface of the window opening rigid core board; The etching and ablation groove of the upper flexible board or the lower flexible board is arranged toward the windowed rigid core board; The coverage range of the first through window and the second through window includes the range of the flexible board area; Then, pre-pressing is performed, and the first through window and the second through window form a pre-pressed window opening groove; S220: a release pad is arranged in the pre-pressed window groove, and the lower flexible board or the upper flexible board is aligned and stacked on one side of the release pad, and then pressed together to form the pressed board.

3. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer as claimed in claim 2, characterized in that: An edge groove is made at the edge of the release pad adjacent to the rigid-flex combination position. After the release pad is set, glue is dispensed into the edge groove, and the glue is filled with a release agent.

4. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer as claimed in claim 3, characterized in that: The release agent is a PTFE release agent with a viscosity of 350 dPa·s to 900 dPa·s.

5. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer as claimed in claim 2, characterized in that: The size of one side of the release pad is smaller than or equal to the size of the pre-pressed window opening groove.

6. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer as claimed in claim 2, characterized in that: The release pad is made of PTFE, PI, TPX, ETFE or silicone.

7. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer as claimed in claim 2, characterized in that: The groove body of the pre-pressed window groove within the range of the flexible plate area is the groove body; The pre-pressed window slot is also provided with an auxiliary slot body extending from the slot body to the auxiliary area; The auxiliary slot body is a protruding slot body structure that is connected to the slot body and is greater than or equal to a quadrilateral; The release pad is provided with an auxiliary fixing area corresponding to the auxiliary groove structure.

8. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer as claimed in claim 2, characterized in that: The pre-pressing is performed at a temperature of 140° C. to 180° C., using a pressure of 15 kg / cm² to 25 kg / cm², for 2 minutes to 10 minutes.

9. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer according to claim 1, characterized in that: The forming of the pressed plate comprises: S210A: Arranging the prepreg layer on the upper and lower surfaces of the rigid core board, and pre-pressing them to form a pre-pressed core board; According to the molding line, a through groove is made at the edge position of the rigid plate area of ​​the pre-pressed core plate corresponding to the rigid-flex combination position to form a pre-cut groove; The pre-pressed core plate is processed to form a pre-grooved core plate; S220A: Align and stack the upper flexible board, the pre-grooved core board, and the lower flexible board in sequence, and then press them together to form the pressed board.

10. The method for manufacturing a rigid-flexible board with a cross-surface flexible layer according to claim 9, characterized in that: The through grooves are made by milling, or by laser ablation of the insulating medium layer combined with etching of the copper layer.

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