CN115666016B - Manufacturing method of ultrathin high-shielding flexible circuit board - Google Patents
Manufacturing method of ultrathin high-shielding flexible circuit board Download PDFInfo
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- CN115666016B CN115666016B CN202211168451.7A CN202211168451A CN115666016B CN 115666016 B CN115666016 B CN 115666016B CN 202211168451 A CN202211168451 A CN 202211168451A CN 115666016 B CN115666016 B CN 115666016B
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 40
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 152
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 152
- 239000003292 glue Substances 0.000 claims abstract description 144
- 238000009713 electroplating Methods 0.000 claims abstract description 68
- 238000000034 method Methods 0.000 claims abstract description 54
- 238000003475 lamination Methods 0.000 claims abstract description 28
- 238000003825 pressing Methods 0.000 claims abstract description 27
- 238000005530 etching Methods 0.000 claims abstract description 24
- 238000000608 laser ablation Methods 0.000 claims abstract description 11
- 239000010410 layer Substances 0.000 claims description 243
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 62
- 229910052802 copper Inorganic materials 0.000 claims description 61
- 239000010949 copper Substances 0.000 claims description 61
- 239000000853 adhesive Substances 0.000 claims description 22
- 230000001070 adhesive effect Effects 0.000 claims description 22
- 239000012530 fluid Substances 0.000 claims description 18
- 239000012790 adhesive layer Substances 0.000 claims description 11
- 230000009969 flowable effect Effects 0.000 claims description 11
- 238000005520 cutting process Methods 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 238000004080 punching Methods 0.000 claims description 6
- 230000001681 protective effect Effects 0.000 claims description 4
- 239000000565 sealant Substances 0.000 claims description 4
- 238000009826 distribution Methods 0.000 claims description 3
- 238000005452 bending Methods 0.000 abstract description 3
- 238000000059 patterning Methods 0.000 abstract 1
- 239000010408 film Substances 0.000 description 104
- 230000000694 effects Effects 0.000 description 12
- 238000010586 diagram Methods 0.000 description 8
- 238000005498 polishing Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 239000011347 resin Substances 0.000 description 6
- 238000007650 screen-printing Methods 0.000 description 6
- 239000011241 protective layer Substances 0.000 description 4
- 238000005553 drilling Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000002313 adhesive film Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 239000013039 cover film Substances 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005429 filling process Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000004026 adhesive bonding Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000002346 layers by function Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- -1 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
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- 230000008054 signal transmission Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000000576 supplementary effect Effects 0.000 description 1
Landscapes
- Structure Of Printed Boards (AREA)
- Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
Abstract
The invention discloses a manufacturing method of an ultrathin high-shielding flexible circuit board, which comprises the following steps: patterning two sides of a double-sided flexible copper-clad plate, manufacturing a through hole, attaching an opening window electroplating auxiliary aluminum sheet to electroplate to form a through hole, performing special typesetting treatment of glue filling and release by using a one-time lamination mode, performing glue filling processing on the through hole, performing laser ablation and pattern etching processing on the flexible plate, and attaching a shielding film to process to form an ultrathin high-shielding flexible circuit board; the flexible circuit board is subjected to redistribution and structure adjustment, so that the thinning of the shielding type and structure of the flexible circuit board is improved, electroplating processing is performed by utilizing a special structure, and special processing of directly pressing prepreg filling holes is performed at one time, so that the ultrathin high-shielding flexible circuit board which is high in reliability, simple and convenient to process, has the thickness not exceeding the standard, has multiple bending performance and has good shielding performance is formed.
Description
Technical Field
The invention relates to the field of flexible circuit board design and processing, in particular to a manufacturing method of an ultrathin high-shielding flexible circuit board.
Background
In some electronic modules (such as high-precision inspection and detection apparatuses) with high precision and required to have three-dimensional assembly or repeated bending application requirements, an ultrathin flexible circuit board with high softness is required, and meanwhile, some precision apparatuses have high requirements on the strength and stability of signal transmission of the circuit board, and the signal and impedance performance of the via hole, an ultrathin high-shielding flexible circuit board is used.
At present, for an ultrathin high-shielding flexible circuit board, a transmission line is generally arranged in the middle, shielding line layers are respectively arranged on the upper surface and the lower surface of the transmission line, and then a protective layer (a covering film layer) is covered to form the effect of the high-shielding flexible circuit board; however, for the flexible circuit board requiring two-sided conduction, there is a design of a via hole, and the circuit board is generally designed to be at least two-sided, and the via hole is increased by a certain thickness of the flexible circuit board, and if shielding circuit layers and covering protection layers are arranged on the upper and lower sides, the overall thickness of the circuit board product is thicker, so that the ultrathin property of the circuit board product is affected, and the practical application effect is affected.
For the ultrathin high-shielding flexible circuit board with the through holes, the general manufacturing mode is that patterns are manufactured on the double-sided copper-clad plate, then drilling processing of the through holes is carried out, electroplating processing of the flexible circuit board is carried out, then the adhesive layer and the shielding circuit layer are pressed, then the shielding circuit layer is manufactured, and then the film layer is pressed and covered, so that the flexible circuit board product is formed.
In the processing process, the electroplating processing generally adopts a whole-plate direct processing mode, on one hand, the flexible circuit board is thinner, the flexible circuit board is easy to twist and bend in the electroplating process, the problems of uneven electroplating, electroplating leakage, tearing of the flexible circuit board and the like are easy to occur, and on the other hand, the whole thickness of the flexible circuit board is increased by direct electroplating, and the plate thickness is easy to exceed the standard; the flexible circuit board is further required to be continuously manufactured with the adhesive layer, the shielding circuit layer and the covering film layer, therefore, the via hole is required to be subjected to solid treatment, the via hole is generally subjected to solid treatment by adopting a mode of screen printing filling resin ink, and the screen printing resin ink is easy to cause expansion and shrinkage exceeding of the circuit board and even tearing of the circuit board, the screen printing resin ink overflows out of the hole, polishing is required, a polishing tool and parameters with high precision are required to be adjusted in the polishing process of the ultrathin flexible circuit board, and a relatively firm and smooth supporting layer is required to be attached, so that polishing of the ultrathin flexible circuit board is generally basically not feasible.
Accordingly, in view of the above problems, there is a need to provide a method for manufacturing an ultra-thin high-shielding flexible circuit board that has good workability and is capable of satisfying thickness control of an ultra-thin flexible circuit board.
Disclosure of Invention
The invention aims to solve the problems that the thickness of an ultrathin high-shielding flexible circuit board is easy to exceed standard and the processing control difficulty is high in the prior art, and provides a manufacturing method of the ultrathin high-shielding flexible circuit board, which is characterized by comprising the following steps of:
s10: the method comprises the steps of taking a double-sided flexible copper-clad plate, wherein the double-sided flexible copper-clad plate comprises a circuit copper layer and a shielding copper layer, baking the double-sided flexible copper-clad plate, performing copper reduction processing after baking, performing circuit pattern manufacturing processing, manufacturing a circuit wiring pattern on the circuit copper layer, manufacturing an auxiliary circuit wiring pattern on the shielding copper layer, and forming the circuit pattern flexible plate.
S20: and manufacturing a through hole on the circuit pattern flexible board to form the through hole flexible board.
S30: attaching dry films to two sides of the through hole flexible board, windowing and manufacturing a dry film pattern, exposing the through hole, attaching an opening window electroplating auxiliary aluminum sheet on the dry film on one side of the auxiliary circuit wiring pattern, wherein the size of the opening window electroplating auxiliary aluminum sheet is larger than or equal to that of the through hole flexible board, an aluminum sheet opening window area is processed on the opening window electroplating auxiliary aluminum sheet, and the single side of the aluminum sheet opening window area is larger than the size of the dry film pattern opening window; an aluminum sheet is integrally formed to assist the flexible board.
S40: and electroplating the aluminum sheet auxiliary flexible board to form a via hole by electroplating, wherein the via hole comprises a glue filling via hole and a non-glue filling via hole, then microetching is performed, and then the electroplating auxiliary aluminum sheet is removed and subjected to film stripping treatment to form the via hole flexible board.
S50: and performing glue filling processing treatment on the via hole flexible board, wherein the glue filling processing treatment comprises the following steps:
s510: the laminated flexible board is formed by sequentially arranging a first flowing glue prepreg layer, a first release film layer, a second flowing glue prepreg layer and a second release film layer on one surface of the circuit wiring pattern of the via flexible board, and sequentially arranging a third flowing glue prepreg layer, a third release film layer, a fourth flowing glue prepreg layer and a fourth release film layer on one surface of the auxiliary circuit wiring pattern of the via flexible board;
s520: riveting, namely riveting the stacked flexible boards by using rivets 5010, wherein the positions of the rivets 5010 are positioned in board edge areas of all unit sub-boards of the stacked flexible boards, and the number of the rivets 5010 in the board edge areas of all unit sub-boards is more than or equal to 2, so as to form a riveted flexible board 500A;
S530: pressing, namely arranging a first pressing aluminum sheet 5020 and a second pressing aluminum sheet 5030 on two sides of the riveted flexible plate 500A respectively, typesetting, and pressing to form a pressed flexible plate 500B;
s540: and disassembling, namely cutting the laminated flexible board 500B, cutting out the position area of the rivet 5110, and disassembling the first release film layer 520, the second flowable adhesive prepreg layer 530, the second release film layer 540, the third release film layer 550, the fourth flowable adhesive prepreg layer 570 and the fourth release film layer 580 to form the filled flexible board 500.
S60: and carrying out laser ablation and pattern etching processing on the glue filling flexible board to form the surface pattern flexible board.
S70: and (3) processing the surface pattern flexible board by attaching a shielding film to form the ultrathin high-shielding flexible circuit board.
Further, the baking of S10 is baking with a baking parameter of 140 ℃ x 30 min.
Further, the thickness of the double-sided flexible copper-clad plate in the S10 is less than or equal to 70 mu m; and the copper reduction processing is performed on the double-sided flexible copper-clad plate, so that the copper layer of the double-sided flexible copper-clad plate is thinned to 10-15 mu m.
Further, the S30 includes:
s310: taking an auxiliary aluminum sheet, coating a strippable adhesive layer on one surface of the auxiliary aluminum sheet, attaching an aluminum sheet protective dry film on the other surface, and performing exposure processing to form an electroplating auxiliary aluminum sheet;
s320: manufacturing an aluminum sheet opening window area for the electroplating auxiliary aluminum sheet, wherein the aluminum sheet opening window area corresponds to the dry film pattern opening window area and is 10-50 mu m larger than the single side of the dry film pattern opening window area in size to form an opening window electroplating auxiliary aluminum sheet;
s330: and coating one surface of the opening window electroplating auxiliary aluminum sheet with the strippable adhesive layer, attaching the aluminum sheet on the dry film on one surface of the auxiliary circuit wiring pattern, and integrally forming the aluminum sheet auxiliary flexible board.
Further, the step S40 is to perform electroplating processing on the aluminum sheet auxiliary flexible board and perform microetching processing, and is to perform electroplating processing on the whole aluminum sheet auxiliary flexible board, wherein the copper thickness of the inner wall of the through hole formed by the electroplating processing is greater than the copper thickness required by the predetermined processing data, and the microetching processing is to perform copper reduction etching processing on the aluminum sheet auxiliary flexible board after the electroplating processing.
Further, the reduced copper etching process is to etch away copper of 3 μm to 8 μm thick.
Further, the first flowable adhesive prepreg layer of S510 is set according to the thickness requirement of the predetermined processing data of the ultra-thin high-shielding flexible circuit board;
the first flow glue prepreg layer is provided with a first through window area, and the first through window area corresponds to the non-filling glue conducting hole and is larger than the non-filling glue conducting Kong Shanbian by a certain distance;
the first release film layer is provided with a second window area which is arranged corresponding to the glue filling through hole and is larger than the glue filling through Kong Shanbian by a certain distance;
the third fluid adhesive prepreg layer has the same structure as the first fluid adhesive semi-cured sheet layer;
the third release film layer has the same structure as the first release film layer;
the second gummosis prepreg layer, the fourth gummosis prepreg layer, the second release film layer and the fourth release film layer are all free of windowing;
the first fluid glue prepreg layer, the first release film layer, the second fluid glue prepreg layer, the third release film layer and the fourth fluid glue prepreg layer are equal to the flexible board of the through hole in size;
The size single side of the second release film layer and the fourth release film layer is larger than the size of the via hole flexible board;
the glue content of the first fluid glue prepreg layer, the second fluid glue prepreg layer, the third fluid glue prepreg layer and the fourth fluid glue prepreg layer is more than or equal to 65%, and the glue overflow amount under the pressing condition is less than or equal to 0.2mm.
Further, the pressing in the step S530 is vacuum pressing, and before the pressing, cold pressing is performed for 30min at normal temperature, wherein the pressure is 160PSI to 220PSI; after the lamination is completed, cold pressing is carried out for 30min at normal temperature, and the pressure is 160PSI to 220PSI.
Further, the step S60 of performing laser ablation and pattern etching processing on the underfill flexible board to form a surface pattern flexible board:
s610: carrying out laser ablation on the glue filling flexible board, punching through grooves on the side edges of corresponding unit flexible boards of the glue filling flexible board, and reserving certain connecting positions, wherein the connecting positions enable the unit flexible board to be integrally and fixedly connected to the glue filling flexible board;
s620: manufacturing a support aluminum sheet, namely taking a support aluminum sheet layer, wherein the single side size of the support aluminum sheet layer is larger than the size of the glue filling flexible sheet, respectively adhering a micro-mucosa layer and a blue glue layer on two sides of the support aluminum sheet layer to form a film-covered support aluminum sheet, and manufacturing a hollowed-out area according to the distribution and the appearance of the unit flexible sheet corresponding to the film-covered support aluminum sheet;
S630: attaching one surface of the micro-mucosa layer of the support aluminum sheet to the glue filling flexible board in a contraposition manner, wherein the hollowed-out area corresponds to the unit flexible board to form a back-attached support aluminum sheet flexible board;
s640: and carrying out pattern etching processing on the back-attached support aluminum sheet flexible board, and removing the support aluminum sheet to form the surface pattern flexible board.
Further, the thickness of the ultrathin high-shielding flexible circuit board is less than or equal to 130 mu m.
According to the technical scheme, the layout of the flexible circuit board is redistributed to form a form of one side of circuit wiring pattern and the other side of auxiliary circuit wiring pattern, and the laminated structure of the flexible circuit board is readjusted to form a double-sided structure which is beneficial to processing of the ultrathin high-shielding flexible circuit board; in the processing process, the auxiliary aluminum sheet is used for fixing and electroplating, so that the electroplating quality of the ultrathin flexible circuit board can be effectively improved, and the auxiliary aluminum sheet is effectively removed by designing the processing flow, so that the flexible circuit board is not additionally influenced; the parameters of the prepregs are adjusted by utilizing the lamination processing characteristics of the lamination process, and special typesetting and processing of directly laminating the prepregs for hole filling are performed at one time, so that an efficient, high-reliability and convenient-to-process hole filling process is formed; by attaching the shielding film, the shielding performance of the flexible circuit board can be effectively improved under the condition that the plate thickness is not out of standard; the whole processing technology has high flow reliability and simple and convenient processing, can effectively ensure that the thickness of the ultrathin high-shielding flexible circuit board is not out of standard, and has multiple bending performance and good shielding performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic cross-sectional view of a typical ultra-thin high-shielding flexible circuit board of the prior art;
FIG. 2 is a process flow diagram of a process technique according to an embodiment of the invention;
FIG. 3 is a process flow diagram of the S50 processing technique of FIG. 2 in accordance with an embodiment of the present invention;
FIG. 4 is a schematic cross-sectional view of a flexible board for processing and forming circuit patterns according to an embodiment of the present invention;
FIG. 5 is a schematic cross-sectional view of a flexible board with through holes formed by processing according to an embodiment of the present invention;
FIG. 6 is a process flow diagram of a process for forming an aluminum sheet auxiliary flexible board according to an embodiment of the present invention;
FIG. 7 is a schematic cross-sectional structure of an auxiliary flexible board formed by processing an aluminum sheet according to an embodiment of the present invention;
fig. 8 is a schematic cross-sectional structure of an aluminum sheet auxiliary flexible board after an electroplating process according to an embodiment of the present invention;
FIG. 9 is a schematic cross-sectional view of a flexible board with via holes formed by processing according to an embodiment of the present invention;
FIG. 10 is a schematic cross-sectional view of a laminated flexible board formed by processing according to an embodiment of the present invention;
FIG. 11 is a schematic cross-sectional view of a flexible board formed by processing glue according to an embodiment of the invention;
FIG. 12 is a schematic cross-sectional view of a flexible board with a surface pattern formed by processing according to an embodiment of the present invention;
FIG. 13 is a process flow diagram of an alternative process for forming a surface pattern flexible sheet in accordance with an embodiment of the present invention;
fig. 14 is a schematic view showing a front plane structure of the glue filled flexible plate adhered to the aluminum support sheet according to the embodiment of the present invention;
fig. 15 is a schematic view showing a back plane structure of the glue filled flexible plate adhered to the aluminum support sheet according to the embodiment of the present invention;
FIG. 16 is a schematic cross-sectional structure of an embodiment of the present invention in which a glue filled flexible sheet is adhered to a support aluminum sheet;
fig. 17 is a schematic cross-sectional structure of an ultra-thin high shielding flexible circuit board formed by processing according to an embodiment of the present invention.
Reference numerals illustrate:
| reference numerals | Name of the name | Reference numerals | Name of the name |
| 010X | First cover film of the prior art | 500 | Glue filling flexible board |
| 020X | Prior art first shield copper layer | 510 | First sealant prepreg layer |
| 030X | First insulating dielectric layer of prior art | 520 | First release film layer |
| 040X | Pure glue layer of the prior art | 530 | Second flowable adhesive prepreg layer |
| 050X | Prior art layout circuit layer | 540 | Second release film layer |
| 060X | Prior art second insulating dielectric layer | 550 | Third glue prepreg layer |
| 070X | Prior art second shield copper layer | 560 | Third release film layer |
| 080X | Prior art second cover film | 570 | Fourth gummosis prepreg layer |
| 100 | Circuit pattern flexible board | 580 | Fourth release film layer |
| 110 | Circuit wiring pattern | 5010 | Rivet |
| 120 | Copper-clad plate dielectric insulating layer | 5020 | First pressed aluminum sheet |
| 130 | Auxiliary line wiring pattern | 5030 | Second pressed aluminum sheet |
| 200 | Through holeFlexible board | 5110 | A first window region |
| 210 | Through hole | 5120 | Second window region |
| 300 | Aluminum sheet auxiliary flexible board | 500A | Riveting flexible board |
| 330 | Opening window electroplating auxiliary aluminum sheet | 500B | Press-fit flexible board |
| 310 | First dry film layer | 2110A | Finished product glue filling via hole |
| 320 | Second dry film layer | 2120A | Non-glue filling through hole |
| 3110 | Dry film pattern window | 500C | Unit flexible board |
| 3310 | Aluminum sheet | 500D | Through groove |
| 3320 | Coating a peelable glue layer | 500E | Connection position |
| 3330 | Aluminum sheet protection dry film | 5040 | Support aluminum sheet |
| 3340 | Aluminum sheet window opening area | 5040A | Support aluminum sheet layer |
| 330A | Electroplating auxiliary aluminum sheet | 5040B | Micro-mucosal layer |
| 210A | Via hole | 5040C | Blue glue layer |
| 2110 | Glue filling via hole | 5040D | Hollow area |
| 2120 | Non-filling glue via hole | 600 | Surface pattern flexible board |
| 330A | Electroplating auxiliary aluminum sheet | 610 | Shielding film |
| 400 | Via hole flexible board | 10 | Ultrathin high-shielding flexible circuit board |
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Referring to fig. 1, fig. 1 is a schematic cross-sectional structure of a typical ultrathin high-shielding flexible circuit board in the prior art.
In the prior art, in order to improve the shielding performance of a layout circuit layer of a flexible circuit board, three-layer circuit design is generally adopted in consideration of factors such as processing technology difficulty, processing cost, product effect and the like, namely, a layer of circuit copper layer is additionally designed on the upper surface and the lower surface of the layout circuit layer, and the circuit copper layer is used for carrying out graphic design so as to realize the shielding effect of the circuit copper layer on the layout circuit layer; the circuit copper layer is added, the corresponding functional layers such as an insulating medium layer, a covering film layer, a pure glue layer and the like are added, the electroplating through hole is manufactured, the requirement of conducting or installing a multi-layer circuit is met, and electroplating treatment is also needed, so that the whole thickness of the flexible circuit board is increased, and the flexible circuit board is possibly beyond the application standard range; and when the three-layer flexible circuit board is processed, the two-sided copper-clad plate, the single-sided copper-clad plate, or the three single-sided copper-clad plates, or the two-sided copper-clad plate, the insulating medium layer and the copper foil are required to be processed, so that the processing difficulty is further increased.
Please refer to fig. 2 and fig. 3 and fig. 4; FIG. 2 is a process flow diagram of a process technique according to an embodiment of the invention; FIG. 3 is a process flow diagram of the S50 processing technique of FIG. 2 in accordance with an embodiment of the present invention; fig. 4 is a schematic cross-sectional structure of a flexible board for processing and forming a circuit pattern according to an embodiment of the present invention.
The processing according to the embodiment of the present invention is performed according to fig. 2 and 3, and fig. 4 is a schematic cross-sectional structure of the processing result of step S10 in fig. 2, namely:
s10: taking a double-sided flexible copper-clad plate, wherein the double-sided flexible copper-clad plate comprises a circuit copper layer and a shielding copper layer, baking the double-sided flexible copper-clad plate, performing copper reduction processing after baking, performing circuit pattern manufacturing processing, manufacturing a circuit wiring pattern 110 on the circuit copper layer, and manufacturing an auxiliary circuit wiring pattern 130 on the shielding copper layer to form the circuit pattern flexible plate 100.
The baking adopted in the embodiment is baking with baking parameters of 140 ℃ multiplied by 30 min; the thickness of the double-sided flexible copper-clad plate is less than or equal to 70 mu m; and (3) carrying out copper reduction processing on the double-sided flexible copper-clad plate to thin the copper layer of the double-sided flexible copper-clad plate to 10-15 mu m.
In this embodiment, a double-sided copper-clad plate is directly adopted, a circuit wiring pattern 110 is manufactured on one side, so as to meet the requirement of a layout circuit pattern, some simple circuit patterns are designed and manufactured on one side of an auxiliary circuit wiring pattern 130, meanwhile, copper mesh patterns are manufactured on the other places, or the copper mesh patterns are integrally manufactured, so that a main circuit can be formed on one side of the circuit wiring pattern 110, an auxiliary circuit is arranged on one side of the auxiliary circuit wiring pattern 130, and a through hole or a mounting hole is manufactured, so that the layout circuit requirement can be met, and the design capable of meeting the high shielding characteristic pattern requirement is formed; the double-sided copper clad laminate is baked to remove internal stress, so that the material stability in the subsequent processing process is facilitated, and the processing coefficient can be accurately set; the copper surface of the copper-clad plate is generally rolled copper, so that the copper-clad plate with copper thickness exceeding the requirement standard is adopted, and microetching copper reduction treatment is carried out to the copper thickness of the requirement standard, so that the copper thickness of the whole rolled copper plate is more uniform, and a uniform and clean rough surface is formed on the surface, thereby being convenient for the use of the subsequent procedure; typically, the copper thickness is reduced by 10 μm to 15 μm, preferably to 12 μm, 13 μm, and to a thinner 8 μm for special applications.
Referring to fig. 5, fig. 5 is a schematic cross-sectional structure of a through-hole flexible board according to an embodiment of the invention; fig. 5 is a schematic cross-sectional structure of the processing result of step S20 in fig. 2, namely:
s20: manufacturing a through hole 210 on the circuit pattern flexible board 100 to form a through hole flexible board 200; in this embodiment, the through hole is manufactured by drilling with a drill or punching or laser drilling.
The through holes are manufactured, so that on one hand, the conduction connection of the double-sided circuit can be met, and on the other hand, the functional requirements of mounting, inserting and the like of the flexible circuit board are met.
FIG. 6 is a process flow diagram of a process for forming an aluminum sheet auxiliary flexible board according to an embodiment of the present invention; fig. 7 is a schematic cross-sectional structure of an auxiliary flexible board processed to form an aluminum sheet according to an embodiment of the present invention.
Fig. 6 and 7 show the processing procedure of step S30 in fig. 2, namely:
s30: attaching dry films to two sides of the through hole flexible board 200, making a window 3110 of a dry film pattern to expose the through hole 210, attaching a window opening electroplating auxiliary aluminum sheet 330 on the dry film on one side of the auxiliary line wiring pattern 130, wherein the size of the window opening electroplating auxiliary aluminum sheet 330 is larger than or equal to that of the through hole flexible board 200, an aluminum sheet window opening area 3340 is processed on the window opening electroplating auxiliary aluminum sheet 330, and the single side of the aluminum sheet window opening area 3340 is larger than the size of the window 3110 of the dry film pattern; an aluminum sheet is integrally formed to assist the flexible board 300.
In this embodiment, the step of S30 further includes:
s310: and taking the auxiliary aluminum sheet 3310, coating a strippable glue layer 3320 on one surface of the auxiliary aluminum sheet 3310, attaching an aluminum sheet protective dry film 3330 on the other surface, and performing exposure processing to form the electroplating auxiliary aluminum sheet 330A.
S320: and manufacturing an aluminum sheet open window area 3340 for the electroplating auxiliary aluminum sheet 330A, wherein the aluminum sheet open window area 3340 corresponds to the area of the dry film pattern open window 3110 and is 10-50 μm larger than the single side of the size of the area of the dry film pattern open window 3110, so as to form the open window electroplating auxiliary aluminum sheet 330.
S330: the open window plating auxiliary aluminum sheet 300 is coated with one side of the peelable adhesive layer 3320 and attached to the dry film 320 of one side of the auxiliary circuit wiring pattern 130 (in this embodiment, the dry film layer of one side of the auxiliary circuit wiring pattern 130 is the second dry film layer 320 and the dry film layer of the other side is the first dry film layer 310), and the aluminum sheet auxiliary flexible sheet 300 is integrally formed.
In this embodiment, since the flexible circuit board is an ultrathin flexible circuit board, if electroplating is directly performed, the problems of uneven electroplating, electroplating leakage, tearing of the flexible circuit board and the like are easily generated, the aluminum sheet is attached to the flexible circuit board, the supportability of the through hole flexible circuit board 200 is enhanced, the auxiliary aluminum sheet 3310 is attached with the peelable adhesive 3320, so that the auxiliary aluminum sheet 3310 can form good adhesive bonding with the through hole flexible circuit board 200, the adhesive layer with a protective layer film can be selected by the peelable adhesive 3320, the protective layer film in the area to be attached is subjected to pattern processing and peeling, the peelable adhesive 3320 is exposed, then the adhesive is attached, the area to be attached is covered by the protective layer film, and the peelable adhesive 3320 can be epoxy resin, polyurethane or polytetrafluoroethylene type peelable adhesive; the aluminum sheet protection dry film 3330 is manufactured on the other surface of the auxiliary aluminum sheet 3310, so that a high-precision film layer for effectively protecting the aluminum sheet can be formed, and the double-sided protection of the auxiliary aluminum sheet 3310 is formed, thereby preventing the aluminum sheet from being plated with copper in the electroplating process and affecting the electroplating processing process; and the through holes 210 corresponding to the aluminum sheets and needing to be electroplated are windowed, so that the liquid medicine exchange of the through holes 210 in the electroplating process is ensured.
In the prior art, the flexible circuit board is generally electroplated by adopting full-board electroplating, namely, electroplating is carried out on the full-board, and then the pattern is manufactured, but the full-board electroplating is directly carried out on the full-board, so that the thickness of the flexible circuit board can be greatly increased, and the flexibility of the flexible circuit board is reduced.
Referring to fig. 8 and 9, fig. 8 is a schematic cross-sectional structure of an aluminum sheet auxiliary flexible board according to an embodiment of the invention after electroplating; FIG. 9 is a schematic cross-sectional view of a flexible board with via holes formed by processing according to an embodiment of the present invention; fig. 8 and 9 show the processing procedure of step S40 in fig. 2, namely:
s40: the aluminum sheet auxiliary flexible board 300 is subjected to electroplating processing, so that the through holes 210 are electroplated to form the through holes 210A, the through holes 210A comprise glue filling through holes 2110 and non-glue filling through holes 2120, then microetching processing is performed, and then the electroplating auxiliary aluminum sheet 330A is removed and subjected to film stripping processing to form the through hole flexible board 400.
In this embodiment, the aluminum sheet auxiliary flexible board 300 is subjected to electroplating processing and micro-etching processing, in order to perform electroplating processing on the whole aluminum sheet auxiliary flexible board 300, the copper thickness of the inner wall of the through hole 210 formed by the electroplating processing is larger than the copper thickness required by the predetermined processing information, and the micro-etching processing is performed to perform copper reduction etching processing on the aluminum sheet auxiliary flexible board 300 after the electroplating processing; the copper-reducing etching process is to etch away copper thickness of 3 μm to 8 μm.
In the electroplating process, not only is the through hole 210A formed by electroplating, but also the copper layer is electroplated on the side wall of the aluminum sheet opening window region 3340 of the aluminum sheet, but since the copper layer electroplated on the side wall of the aluminum sheet opening window region 3340 is thinner, the dry film (the second dry film layer 320) on one side of the auxiliary circuit wiring pattern 130 is further and more connected with the dry film at the combining position of the strippable glue layer 3320, the thickness of the electroplated copper layer is thinner (even the copper layer cannot be electroplated), therefore, the electroplating layer thickness is firstly electroplated to be greater than the finished copper thickness required by the given processing data, the copper layer electroplated on the side wall of the aluminum sheet opening window region 3340 can be etched off by microetching, the copper layer electroplated on the second dry film layer 320 can be further etched off, no copper connection between the flexible circuit board and the auxiliary aluminum sheet is ensured, the condition for removing the aluminum sheet 330A is well removed, and the problem of copper connection in the holes is prevented.
Referring to fig. 10 and 11, fig. 10 is a schematic cross-sectional structure of a laminated flexible board according to an embodiment of the invention; FIG. 11 is a schematic cross-sectional view of a flexible board formed by processing glue according to an embodiment of the invention; fig. 10 and 11 show the processing procedure of step S50 in fig. 2, namely:
s50: the via hole flexible board 400 is subjected to a paste filling process, which includes:
s510: the laminated flexible board is formed by sequentially arranging a first flowing glue prepreg layer 510, a first release film layer 520, a second flowing glue prepreg layer 530 and a second release film layer 540 on one surface of a circuit wiring pattern 110 of the via hole flexible board 400, and sequentially arranging a third flowing glue prepreg layer 550, a third release film layer 560, a fourth flowing glue prepreg layer 570 and a fourth release film layer 580 on one surface of an auxiliary circuit wiring pattern 130 of the via hole flexible board 400.
S520: and riveting, namely riveting the stacked flexible boards by using rivets 5010, wherein the positions of the rivets 5010 are positioned in board edge areas of all unit sub-boards of the stacked flexible boards, and the number of the rivets 5010 in the board edge areas of all unit sub-boards is more than or equal to 2, so as to form the riveted flexible board 500A.
S530: and pressing, namely arranging a first pressing aluminum sheet 5020 and a second pressing aluminum sheet 5030 on two sides of the riveted flexible plate 500A respectively, typesetting, and pressing to form the pressed flexible plate 500B.
S540: disassembling, namely cutting the laminated flexible board 500B, cutting out the position area of the rivet 5110, and disassembling the first release film layer 520, the second flowable adhesive prepreg layer 530, the second release film layer 540, the third release film layer 550, the fourth flowable adhesive prepreg layer 570 and the fourth release film layer 580 to form the glue filling flexible board 500.
Because the thickness of the flexible circuit board is thinner and the via hole 2110 needs to be filled with the glue, in the prior art, the via hole is filled with the glue by adopting a mode of screen printing to fill the resin ink, but because the flexible circuit board is thinner, the screen printing resin ink is easy to cause the expansion and shrinkage of the circuit board to exceed the standard and even tear, and the screen printing resin ink overflows out of the hole, polishing is needed, the polishing of the ultrathin flexible circuit board needs to adjust polishing tools and parameters with high precision, and a firm and smooth supporting layer needs to be attached, so that the polishing of the ultrathin flexible circuit board is generally not feasible; therefore, the present embodiment adopts direct one-time lamination, and uses the prepreg insulation layer (gummed prepreg layer) to fill the glue via 2110.
In this embodiment, the first flowable adhesive prepreg layer 510 and the third flowable adhesive prepreg layer 550 are respectively disposed on two sides of the via hole flexible board 400, so that on one hand, the requirement of the flexible circuit board itself on the insulating medium layer can be satisfied, and on the other hand, the requirement of the flowable adhesive filling adhesive via hole 2110 can be satisfied.
The first release film layer 520 and the third release film layer 560 are respectively arranged on the two sides of the first flow glue prepreg layer 510 and the third flow glue prepreg layer 550, so that the lamination effect of the first flow glue prepreg layer 510 and the third flow glue prepreg layer 550 can be effectively ensured, and the separation after lamination can be well realized.
And set up second gumming prepreg layer 530 and fourth gumming prepreg layer 570, because flexible circuit board is thinner, so set up can prevent that the pressfitting dynamics from producing to pull deformation, the excessive, even pressfitting tearing problem of flexible circuit board, play good cushioning effect to can play fine supplementary effect for the gum filling of gum via hole 2110.
The second release film layer 540 and the fourth release film layer 580 are arranged, so that a good flatness effect can be achieved, and adhesion of gummosis prepregs and lamination stacking structures is prevented.
After stacking, rivets 5010 are used for riveting the periphery of each unit board and the whole board, the number of rivets 5010 forming board edge areas of each unit sub-board is more than or equal to 2, and due to the fact that the release layers are more in the typesetting structure, the rivets 5010 are used for riveting so that the problems of offset, lamination sliding plates and the like can not be generated in lamination, and the lamination quality of each unit board is guaranteed.
During lamination, aluminum sheet layers are arranged on two sides of the riveted flexible board 500A, and the glue filling of the glue filling via hole 2110 and the integral lamination effect of the flexible circuit board can be fully ensured by utilizing heat conduction, certain constraint and good flexibility of the aluminum sheet layers.
Because the release layer is arranged between the layers to be separated in the typesetting structure, when the typesetting structure is disassembled, the press-fit typesetting structure is easily separated only by punching or milling off the riveting position, and the glue filling flexible board 500 is removed.
In this embodiment, the first sealant prepreg layer 510 of S510 is set according to the thickness requirement of the predetermined processing data of the ultra-thin high-shielding flexible circuit board.
The first sealant prepreg layer 510 is provided with a first through window area 5110, and the first through window area 5110 corresponds to the non-filled via 2120 and is a certain distance greater than the single side of the non-filled via 2120; typically 30 μm to 100 μm in size.
The first release film 520 is provided with a second through-hole 5120, and the second through-hole 5120 is arranged corresponding to the glue filling through-hole 2110 and is larger than the single side of the glue filling through-hole 2110 by a certain distance; typically 30 μm to 100 μm in size.
The third flow glue prepreg layer 550 is identical in structure to the first flow glue prepreg layer 510.
The third release film 560 has the same structure as the first release film 520.
It should be noted that, the first and third glue prepreg layers 510 and 550 are not only used as glue prepreg for filling the glue via 2110, but also used as insulating medium layer of the flexible circuit board to perform a dual-purpose function, so that the first and third glue prepreg layers 510 and 550 are set according to the thickness requirement of the predetermined processing data, that is, according to the thickness of the insulating medium layer after lamination, to perform compensation of lamination processing.
And, windows need to be opened in the areas of the non-filled vias 2120 of the first and third glue prepreg layers 510 and 550 to prevent the glue prepreg from flowing into the non-filled via 2120.
The positions of the glue filling through holes 2110 corresponding to the first release film layer 520 and the third release film layer 560 are windowed, so that the glue of the second glue prepreg layer 530 and the fourth glue prepreg layer 570 can flow to the first glue prepreg layer 510 and the third glue prepreg layer 550 through the windowed areas, and the glue filling compensation is performed on the first glue prepreg layer 510 and the third glue prepreg layer 550, so that the glue filling through holes 2110 can be fully filled, and the thickness of the insulating medium layer is not uneven, so that the problems of plate surface depression and the like are solved.
The second and fourth gummed prepreg layers 530 and 570 and the second and fourth release film layers 540 and 580 are not windowed.
The dimensions of the first and first release film layers 510 and 520, the second and third release film layers 530 and 550, and the fourth release film layers 560 and 570 are equal to the dimensions of the via flex plate 400.
The size of the second release film 540 and the fourth release film 580 is larger than the size of the via flexible board 400, and is generally 1.0mm to 3.0mm.
The size of the top layer and the bottom layer release film layer is larger, so that glue overflow generated by each gummosis prepreg layer during lamination can be effectively prevented, the typesetting structure is polluted, and the lamination is influenced.
The glue content of the first flow glue prepreg layer 510, the second flow glue prepreg layer 530, the third flow glue prepreg layer 550 and the fourth flow glue prepreg layer 570 is more than or equal to 65%, and the glue overflow under the lamination condition is less than or equal to 0.2mm.
Each gummosis prepreg layer adopts a prepreg with higher gum content and lower gum overflow amount, so that the effects of pressing and filling the gum through holes 2110 can be effectively ensured, and excessive gum overflow of the prepreg layer can be prevented.
In one embodiment, the second release film 540 has a thickness greater than the first release film 520; the fourth release film 570 has a thickness greater than the third release film 560; the thickness of the first release film layer 520 and the third release film layer 560 is 10 μm to 50 μm, respectively, and preferably may be 30 μm, 40 μm, 50 μm.
The first release film layer 520 and the third release film layer 560 are thinner, which is helpful for the second gummosis prepreg layer 530 and the fourth gummosis prepreg layer 570 to supplement gummosis through the open window area on the release film and is convenient for stripping.
In the embodiment, the lamination is vacuum lamination, and before lamination, cold pressing is performed for 30min at normal temperature, wherein the pressure is 160PSI to 220PSI; after the pressing is finished, cold pressing is carried out for 30min at normal temperature, and the pressure is 160PSI to 220PSI.
The cold pressing time for a certain time is increased before and after lamination, so that the stress formed in lamination can be effectively released, and uneven lamination expansion and shrinkage or exceeding of the standard of the ultrathin flexible circuit board can be prevented.
Referring to fig. 12, fig. 12 is a schematic cross-sectional structure of a flexible board with a surface pattern formed by processing according to an embodiment of the present invention; fig. 12 shows the processing procedure of step S60 in fig. 2, namely:
s60: the underfill flexible sheet 500 is subjected to laser ablation and pattern etching processes to form a surface pattern flexible sheet 600.
After disassembly, since the glue filling via 2110 is filled with the glue of the prepreg, and the opening window areas of the first release film layer 520 and the third release film layer 560 are reserved, the glue of the prepreg of the glue filling via 2110 is higher than the plate surface as shown in fig. 11, so that the glue of the prepreg needs to be removed, but the plate thickness is thinner and cannot be ground down in a practical polishing way, the raised part is removed in a laser ablation way, so that the high-precision processing effect can be achieved, after laser ablation and pattern etching processing, the glue filling via 2110 forms a finished glue filling via 2110A, and the non-glue filling via 2120 forms a finished non-glue filling via 2120A.
Referring to fig. 13, 14, 15 and 16, fig. 13 is a process flow diagram of an alternative processing to form a surface pattern flexible board according to an embodiment of the invention; fig. 14 is a schematic view showing a front plane structure of the glue filled flexible plate adhered to the aluminum support sheet according to the embodiment of the present invention; fig. 15 is a schematic view showing a back plane structure of the glue filled flexible plate adhered to the aluminum support sheet according to the embodiment of the present invention; fig. 16 is a schematic cross-sectional structure of the glue filled flexible plate adhered to the aluminum support sheet according to the embodiment of the present invention.
In this embodiment, S60 further includes:
s610: the glue filling flexible board 500 is subjected to laser ablation, then through grooves 500D are punched on the side edges of the corresponding unit flexible boards 500C of the glue filling flexible board 500, and certain connecting positions 500E are reserved, wherein the connecting positions 500E enable the unit flexible boards 500C to be integrally and fixedly connected to the glue filling flexible board 500.
According to the appearance of the unit flexible board 500C, and punching the through groove 500D is carried out on the side edge, so that the stress of the unit flexible board 500C can be effectively removed, and the connection position 500E enables the unit flexible board 500C not to fall off, namely, the through groove 500D is only used for punching and cutting the part between the unit flexible board 500C and the flexible circuit board body; and the connection position 500E is provided, it is necessary to ensure that the unit flexible board 500C forming the through groove 500D does not have a state in which either end is suspended.
S620: manufacturing a support aluminum sheet 5040, taking a support aluminum sheet layer 5040A, wherein the single side size of the support aluminum sheet layer 5040A is larger than the size of the glue filling flexible plate 500, respectively adhering a micro-mucosa layer 5040B and a blue glue layer 5040C on two sides of the support aluminum sheet layer 5040A to form a film-covered support aluminum sheet, and manufacturing a hollowed-out area 5040D by amplifying the single side of the film-covered support aluminum sheet according to the distribution and the appearance of the corresponding unit flexible plate 500C to form the support aluminum sheet 5040; the unilateral magnification is typically 30 μm to 100 μm.
The glue filling flexible board 500 is reinforced and supported by using the support aluminum sheet 5040, and the glue filling flexible board 500 is processed to form the unit flexible board 500C, so that the tearing problem of the glue filling flexible board 500 in the processing processes of etching and the like can be effectively prevented; the aluminum support sheet 5040 and the glue filling flexible board 500 are adhered by using a micro-adhesive film, and the micro-adhesive film can be used for selectively windowing the protective film layer at the position to be adhered and adhering to form an effective integral processing structure; the hollow area 5040D of the support aluminum sheet 5040 can be effectively matched with the through groove 500D, and after the glue filling flexible board 500 is attached to the support aluminum sheet 5040, a certain free area is formed between the hollow area 5040D and the through groove 500D, so that liquid medicine can be fully exchanged in the subsequent processing processes of etching and the like, and the broken unit flexible board 500C is not washed.
S630: one surface of a micro-adhesive layer 5040B of the support aluminum sheet 5040 is aligned and attached to the glue filling flexible board 500, and the hollowed-out area 5040D corresponds to the unit flexible board 500C to form a back-attached support aluminum sheet flexible board.
S640: the back-attached aluminum support sheet flex is subjected to a pattern etching process, after which the aluminum support sheet 5040 is removed to form the surface pattern flex 600.
Since the aluminum support sheet 5040 is protected by the micro-adhesive layer and the blue adhesive layer and the etching liquid has a limited etching effect on the aluminum support sheet 5040, the etching does not cause excessive damage to the aluminum support sheet 5040.
Referring to fig. 17, fig. 17 is a schematic cross-sectional structure of an ultrathin high-shielding flexible circuit board formed by processing according to an embodiment of the invention; fig. 17 shows the processing procedure of step S70 in fig. 2, namely:
s70: the surface pattern flexible board 600 is subjected to processing of attaching a shielding film 610 to form an ultrathin high-shielding flexible circuit board 10; in this embodiment, the thickness of the ultra-thin high-shielding flexible circuit board 10 is 130 μm or less.
In this embodiment, the shielding performance of the flexible circuit board is satisfied and increased by attaching the shielding film 610 to the surface pattern flexible board 600, and the shielding film 610 is generally thinner and has higher flexibility, so that the requirements of the flexible circuit board on ultra-thin property and high flexibility can be satisfied; when the shielding film 610 is attached, the shielding film 610 needs to be windowed according to the required attached figure, and quick press fit attachment is adopted to form a good processing effect; through the processing, the thickness of the flexible circuit board can be less than 130 mu m.
It should be noted that, because different designs, processing and application situations of the flexible circuit board exist in the actual processing and application processes, the drawing of the embodiment is only used as an implementation process for illustrating the embodiment, and does not represent the dimension proportion of the actual product or the drawing of the equal scale enlargement according to the actual situation.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (10)
1. The manufacturing method of the ultrathin high-shielding flexible circuit board is characterized by comprising the following steps of:
s10: the method comprises the steps of taking a double-sided flexible copper-clad plate, wherein the double-sided flexible copper-clad plate comprises a circuit copper layer and a shielding copper layer, baking the double-sided flexible copper-clad plate, performing copper reduction processing after baking, performing circuit pattern manufacturing processing, manufacturing a circuit wiring pattern on the circuit copper layer, manufacturing an auxiliary circuit wiring pattern on the shielding copper layer, and forming a circuit pattern flexible plate;
s20: manufacturing a through hole on the circuit pattern flexible board to form a through hole flexible board;
s30: attaching dry films to two sides of the through hole flexible board, windowing and manufacturing a dry film pattern, exposing the through hole, attaching an opening window electroplating auxiliary aluminum sheet on the dry film on one side of the auxiliary circuit wiring pattern, wherein the size of the opening window electroplating auxiliary aluminum sheet is larger than or equal to that of the through hole flexible board, an aluminum sheet opening window area is processed on the opening window electroplating auxiliary aluminum sheet, and the single side of the aluminum sheet opening window area is larger than the size of the dry film pattern opening window; integrally forming an aluminum sheet auxiliary flexible board;
S40: electroplating the aluminum sheet auxiliary flexible board to enable the through holes to be electroplated to form through holes, wherein the through holes comprise filled through holes and non-filled through holes, microetching is carried out, then the electroplating auxiliary aluminum sheet is removed, and film stripping treatment is carried out to form the through hole flexible board;
s50: and performing glue filling processing treatment on the via hole flexible board, wherein the glue filling processing treatment comprises the following steps:
s510: the laminated flexible board is formed by sequentially arranging a first flowing glue prepreg layer, a first release film layer, a second flowing glue prepreg layer and a second release film layer on one surface of the circuit wiring pattern of the via flexible board, and sequentially arranging a third flowing glue prepreg layer, a third release film layer, a fourth flowing glue prepreg layer and a fourth release film layer on one surface of the auxiliary circuit wiring pattern of the via flexible board;
s520: riveting, namely riveting the stacked flexible plates by using rivets, wherein the positions of the rivets are positioned in the plate edge areas of all the unit sub-plates of the stacked flexible plates, and the number of the rivets in the plate edge areas of all the unit sub-plates is more than or equal to 2 to form a riveted flexible plate;
S530: pressing, namely respectively arranging a first pressing aluminum sheet and a second pressing aluminum sheet on two sides of the riveted flexible board, typesetting, and then pressing to form the pressed flexible board;
s540: disassembling, namely cutting the laminated flexible board, cutting out the position area of the rivet, and disassembling the first release film layer, the second flowable adhesive prepreg layer, the second release film layer, the third release film layer, the fourth flowable adhesive prepreg layer and the fourth release film layer to form a glue filling flexible board;
s60: performing laser ablation and pattern etching processing on the glue filled flexible board to form a surface pattern flexible board;
s70: and (3) processing the surface pattern flexible board by attaching a shielding film to form the ultrathin high-shielding flexible circuit board.
2. The method of manufacturing an ultra-thin high shielding flexible circuit board according to claim 1, wherein said baking of S10 is performed with a baking parameter of 140 ℃ x 30 min.
3. The method for manufacturing the ultrathin high-shielding flexible circuit board according to claim 1, wherein the thickness of the double-sided flexible copper-clad plate in the step S10 is less than or equal to 70 mu m; and the copper reduction processing is performed on the double-sided flexible copper-clad plate, so that the copper layer of the double-sided flexible copper-clad plate is thinned to 10-15 mu m.
4. The method for manufacturing an ultra-thin high shielding flexible circuit board according to claim 1, wherein S30 comprises:
s310: taking an auxiliary aluminum sheet, coating a strippable adhesive layer on one surface of the auxiliary aluminum sheet, attaching an aluminum sheet protective dry film on the other surface, and performing exposure processing to form an electroplating auxiliary aluminum sheet;
s320: manufacturing an aluminum sheet opening window area for the electroplating auxiliary aluminum sheet, wherein the aluminum sheet opening window area corresponds to the dry film pattern opening window area and is 10-50 mu m larger than the single side of the dry film pattern opening window area in size to form an opening window electroplating auxiliary aluminum sheet;
s330: and coating one surface of the opening window electroplating auxiliary aluminum sheet with the strippable adhesive layer, attaching the aluminum sheet on the dry film on one surface of the auxiliary circuit wiring pattern, and integrally forming the aluminum sheet auxiliary flexible board.
5. The method for manufacturing an ultra-thin high-shielding flexible circuit board according to claim 4, wherein the step S40 of electroplating the aluminum sheet auxiliary flexible board and performing microetching is performed to perform electroplating processing on the whole aluminum sheet auxiliary flexible board, the copper thickness of the inner wall of the through hole formed by the electroplating processing is larger than the copper thickness required by the predetermined processing data, and the microetching is performed to perform copper reduction etching on the aluminum sheet auxiliary flexible board after the electroplating processing.
6. The method of manufacturing an ultra-thin high shielding flexible circuit board according to claim 5, wherein the copper-reducing etching process is etching copper thickness of 3 μm to 8 μm.
7. The method of claim 1, wherein the first sealant prepreg layer of S510 is set according to thickness requirements of predetermined processing data of the ultra-thin high-shielding flexible circuit board;
the first flow glue prepreg layer is provided with a first through window area, and the first through window area corresponds to the non-filling glue conducting hole and is larger than the non-filling glue conducting Kong Shanbian by a certain distance;
the first release film layer is provided with a second window area which is arranged corresponding to the glue filling through hole and is larger than the glue filling through Kong Shanbian by a certain distance;
the third fluid adhesive prepreg layer has the same structure as the first fluid adhesive semi-cured sheet layer;
the third release film layer has the same structure as the first release film layer;
the second gummosis prepreg layer, the fourth gummosis prepreg layer, the second release film layer and the fourth release film layer are all free of windowing;
the first fluid glue prepreg layer, the first release film layer, the second fluid glue prepreg layer, the third release film layer and the fourth fluid glue prepreg layer are equal to the flexible board of the through hole in size;
The size single side of the second release film layer and the fourth release film layer is larger than the size of the via hole flexible board;
the glue content of the first fluid glue prepreg layer, the second fluid glue prepreg layer, the third fluid glue prepreg layer and the fourth fluid glue prepreg layer is more than or equal to 65%, and the glue overflow amount under the pressing condition is less than or equal to 0.2mm.
8. The method of manufacturing an ultra-thin high-shielding flexible circuit board according to claim 1, wherein the lamination of S530 is vacuum lamination, and cold pressing is performed for 30min at normal temperature and the pressure is 160PSI to 220PSI before the lamination; after the lamination is completed, cold pressing is carried out for 30min at normal temperature, and the pressure is 160PSI to 220PSI.
9. The method for manufacturing an ultra-thin high shielding flexible circuit board according to claim 1, wherein the step S60 of performing laser ablation and pattern etching processing on the glue-filled flexible board forms a surface pattern flexible board:
s610: carrying out laser ablation on the glue filling flexible board, punching through grooves on the side edges of corresponding unit flexible boards of the glue filling flexible board, and reserving certain connecting positions, wherein the connecting positions enable the unit flexible board to be integrally and fixedly connected to the glue filling flexible board;
S620: manufacturing a support aluminum sheet, namely taking a support aluminum sheet layer, wherein the single side size of the support aluminum sheet layer is larger than the size of the glue filling flexible sheet, respectively adhering a micro-mucosa layer and a blue glue layer on two sides of the support aluminum sheet layer to form a film-covered support aluminum sheet, and manufacturing a hollowed-out area according to the distribution and the appearance of the unit flexible sheet corresponding to the film-covered support aluminum sheet;
s630: attaching one surface of the micro-mucosa layer of the support aluminum sheet to the glue filling flexible board in a contraposition manner, wherein the hollowed-out area corresponds to the unit flexible board to form a back-attached support aluminum sheet flexible board;
s640: and carrying out pattern etching processing on the back-attached support aluminum sheet flexible board, and removing the support aluminum sheet to form the surface pattern flexible board.
10. The method for manufacturing an ultrathin high-shielding flexible circuit board according to claim 1, wherein the thickness of the ultrathin high-shielding flexible circuit board is less than or equal to 130 μm.
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| CN113163605A (en) * | 2021-04-21 | 2021-07-23 | 深圳市祺利电子有限公司 | Manufacturing method of high-heat-dissipation aluminum-based circuit board and high-heat-dissipation aluminum-based circuit board |
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