CN106376189B

CN106376189B - Multilayer flexible circuit board manufacturing method and multilayer flexible circuit board

Info

Publication number: CN106376189B
Application number: CN201611074928.XA
Authority: CN
Inventors: 詹世敬; 吴传亮
Original assignee: Zhuhai GCI Science and Technology Co Ltd
Current assignee: Zhuhai GCI Science and Technology Co Ltd
Priority date: 2016-11-29
Filing date: 2016-11-29
Publication date: 2023-04-28
Anticipated expiration: 2036-11-29
Also published as: CN106376189A

Abstract

The multi-layer flexible circuit board consists of N double-sided core plates, N+1 layers of covering films and N-1 layers of adhesive bonding layers; the double-sided core plate sequentially comprises a circuit layer, a medium layer and a circuit layer; the covering films are arranged between the upper outer surface and the lower outer surface of the flexible circuit board and the adjacent two double-sided core boards, and the adhesive bonding layer is arranged between the covering films of the adjacent two core boards and the circuit layer; n is more than or equal to 2. The covering film with the thickness of 15-70UM is used for filling the L12 or L13 layer of circuit and then is pressed with the adhesive bonding layer, so that the defect that the circuit cannot be filled completely effectively due to insufficient thickness of the pure adhesive bonding layer is overcome; in the process of processing, the cover plate is used for pressing by rivets, and in the process of pressing, the rivets effectively fix the core plates of each layer of the plate through the rivet holes, so that the displacement of the plate under high pressure in the pressing process is avoided, and the problems of lamination pressing sliding plates and interlayer dislocation are effectively solved; meanwhile, the cover plate is thickened, so that the defect that the flexible circuit board cannot be riveted due to the thinness of the flexible circuit board can be avoided, and the abnormality of riveting dislocation of the thin plate is solved.

Description

Multilayer flexible circuit board manufacturing method and multilayer flexible circuit board

[ field of technology ]

The invention relates to the technical field of flexible circuit board production, in particular to a flexible circuit board and a production method thereof.

[ background Art ]

With the development of the PCB (Printed Circuit Board), the flexible printed circuit board is rapidly developed in the direction of the multi-layer flexible printed board, which is one of the main growing points in the future of the PCB industry, along with the development of the PCB in the direction of small size, light weight, three-dimensional installation and high connection reliability.

Currently, a manufacturing method of a multi-layer flexible printed board in the industry mainly adopts a structure of a flexible core board, pure glue and a flexible core board (taking four layers as an example, the flexible core board is formed by sequentially laminating a circuit layer L1, a core board dielectric layer 200, a circuit layer L2, an adhesive bonding layer 300, a circuit layer L3, a core board dielectric layer 201 and a circuit layer L4), as shown in fig. 1 below.

1. The layering explodes the board, and the packing is not real, and the reliability is poor.

The thickness of the pure adhesive bonding layer on the market is generally thinner at present and is about 25-40UM, and the thickness of the product is limited, so that the multilayer flexible board is Shan Zhangchun glue filled, copper is filled on two sides of the multilayer flexible board, the copper cannot be effectively filled, a cavity is extremely easy to occur, and the board is layered and exploded after being welded at high temperature.

2. Dislocation between layers and short circuit of inner layer.

Because the core plate of the flexible board is generally thinner, the total thickness of the multi-layer flexible board is generally below 0.5mm, rivets cannot be used for fixing and pressing during pressing, most of the multi-layer flexible board is stuck or fused and positioned by using adhesive paper, the traditional press and the quick press are used for pressing, the pressing pressure is high, the adhesive paper and the fused and positioned are not effectively fixed at high temperature and high pressure, interlayer dislocation abnormality easily occurs, and the board is directly scrapped.

[ invention ]

In view of the above, the present invention provides a method for manufacturing a flexible circuit board with improved production process and a flexible circuit board manufactured by the method.

The invention adopts the following technical scheme:

the manufacturing method of the multilayer flexible circuit board comprises the following steps:

s11: cutting to provide two core plates;

the two core plates are a first core plate and a second core plate respectively; the first core board is composed of a circuit layer L11, a medium layer 121 and a circuit layer L12 from outside to inside; the second core board is composed of a circuit layer L13, a medium layer 122 and a circuit layer L14 from inside to outside; the circuit layer L11 and the circuit layer L14 are circuit pattern surfaces of the outer core plate, and the circuit layer L12 and the circuit layer L13 are circuit pattern surfaces of the inner core plate;

s12: the circuit layers L12 and L13 are manufactured, and the steps include the following steps:

s121: imaging by internal light: manufacturing L12 and L13 circuit patterns according to the pattern films;

s122: and (3) inner layer etching: manufacturing circuit layers L12 and L13 by adopting a chemical etching method;

s123: and (3) inner layer inspection: checking whether the circuit layers L12 and L13 are qualified or not;

s13: the cover film 112 is manufactured, and the steps comprise cutting, cutting and matching auxiliary materials;

s14: laminating the cover film 112 and the circuit layer L12 or L13;

s15: the adhesive layer 131 is manufactured, and the steps comprise cutting, cutting and matching auxiliary materials;

s16: manufacturing two cover plates 14, wherein the cover plates 14 and the two core plates have the same hole sites;

s17: the above materials were arranged in the following order from top to bottom: cover plate 14, line layer L11, dielectric layer 121, line layer L12, cover film 112, adhesive layer 131, line layer L13, dielectric layer 122, line layer L14, cover plate 14 or cover plate 14, line layer L11, dielectric layer 121, line layer L12, adhesive layer 131, cover film 112, line layer L13, dielectric layer 122, line layer L14, cover plate 14;

s18: laminating and riveting: rivet 15 is added in the riveting hole;

s19: laminating, namely laminating all layers of materials of the pre-arranged plates in the step S17;

s110: taking two cover plates 14;

s111: the circuit layers L11 and L14 are manufactured, and the method comprises the following steps:

s1111: drilling: drilling various types of holes in the material obtained in step S19;

s1112: copper deposition: depositing a thin layer of chemical copper on the drilled non-conductive hole wall substrate by a chemical method to serve as a substrate for electroplating in the step S1113;

s1113: electroplating the plate surface: electroplating copper on the plate surface and the hole wall;

s1114: external light imaging: manufacturing outer circuit layers L11 and L14 according to the graphic film;

s1115: image electroplating: electroplating a copper layer reaching a required thickness on the exposed copper sheet or the hole wall of the circuit pattern;

s1116: and (3) outer layer etching: etching the copper layer at the non-circuit part by using a chemical reaction method;

s1117: and (3) outer layer etching inspection: checking whether the manufactured circuit layers L11 and L14 are qualified or not;

s112: the

cover films

111 and 113 are manufactured in the same steps as S13, and the cover film 111 is disposed on the circuit layer L11, and the cover film 113 is disposed under the circuit layer L14 and laminated.

Preferably, the thickness of the cover film is 15-70UM.

Preferably, the cover plate has a thickness of 0.2-1.0 mm.

The beneficial technical effects of the invention are as follows:

1. the covering film with the thickness of 15-70UM is used for filling the L12 or L13 layer of circuit and then is pressed with the adhesive layer, so that the defect that the circuit cannot be effectively and completely filled by the pure adhesive layer is effectively solved, one layer of circuit is filled by the covering film and any layer of circuit of the L12 or L13 layer of circuit is filled, and the other layer of circuit is filled by glue, at the moment, the thickness of the glue can effectively and completely fill the circuit layer and can be well adhered with the covering film, the problems of incomplete filling of glue, lamination holes, layered burst plates and the like are avoided, and the reliability of the board is effectively ensured.

2. The cover plate is used for pressing by the rivets, and the rivets effectively fix the core plates of each layer of the plate through the rivet holes in the pressing process, so that the displacement of the plate under high pressure in the pressing process is avoided, and the problems of lamination pressing sliding plates and interlayer dislocation are effectively solved; meanwhile, the cover plate is thickened, so that the defect that the flexible circuit board cannot be riveted due to the thinness of the flexible circuit board can be avoided, and the abnormality of riveting dislocation of the thin plate is solved; and the cover plate with the thickness of 0.2-1.0 mm can be manufactured, and the selection range is wide.

[ description of the drawings ]

FIG. 1 is a schematic diagram of a prior art four-layer flexible circuit board structure;

FIG. 2 is a schematic diagram illustrating a first manufacturing state of a four-layer flexible printed circuit board according to a first embodiment;

FIG. 3 is a schematic diagram illustrating a second manufacturing state of a four-layer flexible printed circuit board according to a first embodiment;

FIG. 4 is a schematic diagram of a four-layer flexible circuit board structure in a second embodiment.

[ detailed description ] of the invention

In order to make the technical scheme and technical effect of the present patent more clear, the following detailed description of the specific embodiments of the present patent is given with reference to the accompanying drawings and examples.

Embodiment one:

as shown in fig. 2 and 3, the method for manufacturing a multi-layer flexible circuit board in this embodiment, taking a four-layer flexible circuit board as an example, includes the following steps:

s11: cutting to provide two core plates;

the two core plates are a first core plate and a second core plate respectively. The first core board is composed of a circuit layer L11, a dielectric layer 121 and a circuit layer L12 from outside to inside. The second core board is composed of a circuit layer L13, a dielectric layer 122 and a circuit layer L14 from inside to outside. The circuit layers L11 and L14 are circuit pattern surfaces of the outer core board, and the circuit layers L12 and L13 are circuit pattern surfaces of the inner core board.

S12: the wiring layers L12 and L13 are fabricated. The method comprises the following steps:

s13: a cover film 112 is produced. The method comprises the steps of cutting, cutting and matching auxiliary materials.

S14: the cover film 112 is pressed against the wiring layer L12 or L13.

S15: the adhesive layer 131 is formed. The method comprises the steps of cutting, cutting and matching auxiliary materials.

S16: two cover plates 14 are manufactured, and the cover plates 14 and the two core plates have the same hole sites.

S17: the above materials were arranged in the following order from top to bottom: cover plate 14, wiring layer L11, dielectric layer 121, wiring layer L12, cover film 112, adhesive layer 131, wiring layer L13, dielectric layer 122, wiring layer L14, cover plate 14 or cover plate 14, wiring layer L11, dielectric layer 121, wiring layer L12, adhesive layer 131, cover film 112, wiring layer L13, dielectric layer 122, wiring layer L14, cover plate 14.

S18: laminating and riveting: rivet 15 is added in the riveting hole;

s110: taking two cover plates 14 as shown in fig. 3;

s111: the wiring layers L11 and L14 are fabricated. The method comprises the following steps:

s1111: drilling: drilling various types of holes, such as plated holes and electroless plated holes, in the material obtained in step S19;

s1117: and (3) outer layer etching inspection: and checking whether the manufactured circuit layers L11 and L14 are qualified or not.

S112: the

cover films

The processing process after lamination is a step in the prior art, and is not described herein.

According to the manufacturing method of the four-layer flexible circuit board, the L12 or L13 layer circuit is filled with the covering film with the thickness of 15-70UM and then is pressed with the adhesive layer 131, so that the defect that the circuit cannot be effectively and completely filled with the pure adhesive layer is effectively overcome, the covering film is firstly filled with any one layer of the L12 or L13 layer circuit, one layer of the circuit is filled, the other layer of the circuit is filled with glue, at the moment, the circuit layer can be effectively and completely filled with the thickness of the glue, the glue can be well bonded with the covering film, the problems of incomplete glue filling, lamination holes, layered burst plates and the like are avoided, and the reliability of the board is effectively guaranteed.

The cover plate 14 is used for pressing with the rivets 15, and in the pressing process, the rivets 15 effectively fix the core plates of each layer of the plate through the rivet holes, so that the displacement of the plate under high pressure in the pressing process is avoided, and the problems of lamination pressing sliding plates and interlayer dislocation are effectively solved; meanwhile, the cover plate 14 is thickened, so that the defect that the flexible circuit board cannot be riveted due to the thinness can be avoided, and the abnormality of riveting dislocation of the thin plate is solved; and the cover plate with the thickness of 0.2-1.0 mm can be manufactured, and the selection range is wide.

As shown in fig. 3, the four-layer flexible circuit board manufactured by the above-mentioned four-layer flexible circuit board manufacturing method is formed by laminating, from top to bottom, a cover film 111, a circuit layer L11, a dielectric layer 121, a circuit layer L12, a cover film 112, an adhesive layer 131, a circuit layer L13, a dielectric layer 122, a circuit layer L14 and a cover film 113, or laminating, from top to bottom, a cover film 111, a circuit layer L11, a dielectric layer 121, a circuit layer L12, an adhesive layer 131, a cover film 112, a circuit layer L13, a dielectric layer 122, a circuit layer L14 and a cover film 113.

If more layers of circuit boards, such as six layers, eight layers and other layers of flexible circuit boards, are manufactured, the multi-layer flexible circuit board meeting the requirements can be obtained by only adding a covering film with the thickness of 15-70UM between two adjacent core boards and pressing the adhesive bonding layers. The manufacturing method is the same as the manufacturing method of the four-layer flexible circuit board, the internal circuit layers are firstly manufactured, then the covering film and the adhesive bonding layer between the internal circuit layers are manufactured, the external circuit layers and the covering film are manufactured after lamination, and finally the laminated flexible circuit board is manufactured.

The manufacturing method of the four-layer flexible circuit board in the embodiment is also suitable for manufacturing flexible circuit boards with more layers. The multi-layer flexible circuit board manufactured by the method consists of N double-sided core boards, an (N+1) layer covering film and an (N-1) layer adhesive bonding layer; the double-sided core plate sequentially comprises a circuit layer, a medium layer and a circuit layer; the covering films are arranged between the upper outer surface and the lower outer surface of the flexible circuit board and the adjacent two double-sided core boards, and the adhesive bonding layer is arranged between the covering films of the adjacent two core boards and the circuit layer; n is more than or equal to 2.

Embodiment two:

as shown in fig. 4, the method for manufacturing the multi-layer flexible circuit board in this embodiment still uses four layers as an example, and includes the following steps:

s21: cutting to provide three core boards;

the three core plates are a third core plate, a fourth core plate and a fifth core plate respectively. The third core board is composed of a circuit layer L21 and a dielectric layer 221 from outside to inside; the fourth core board is composed of a circuit layer L22, a medium layer 222 and a circuit layer L23 in sequence; the fifth core board is composed of a dielectric layer 223 and a line layer L24 from inside to outside.

S22: manufacturing a circuit layer L22 and a circuit layer L23; the procedure is the same as in S12 of the first embodiment;

s23: the

adhesive layers

231 and 232 are formed, and the adhesive layer forming step is the same as S15 in the first embodiment;

s24: pre-arrangement plates: the above materials were arranged in the following order from top to bottom: line layer L21, dielectric layer 221, adhesive layer 231, line layer L22, dielectric layer 222, line layer L23, dielectric layer 223, adhesive layer 232, dielectric layer 224, line layer L24;

s25: laminating: pressing the layers of materials of the pre-arranged plates in the step S24;

s26: the circuit layers L21 and L24 are produced in the same steps as S111 in the first embodiment;

s27: the

cover films

211 and 212 are formed in the same manner as in S13 of the first embodiment;

s28: pre-arrangement plates: the above materials were arranged in the following order from top to bottom: a cover film 211, a wiring layer L21, a dielectric layer 221, an adhesive bonding layer 231, a wiring layer L22, a dielectric layer 222, a wiring layer L23, a dielectric layer 223, an adhesive bonding layer 232, a wiring layer L24, and a cover film 212;

s29: laminating: and (3) pressing the layers of materials of the pre-row plates in the step S28.

In the method for manufacturing a multilayer flexible circuit board in this embodiment, the following steps may be added before step S24:

s210: two cover plates are manufactured, and the cover plates and the three core plates have the same hole sites. Two cover plates are respectively arranged on the circuit layer L21 and under the circuit layer L24.

S211: laminating and riveting: rivet is added into the rivet hole;

then a step of adding a take-off plate is required after step S25.

The manufacturing method of the multilayer flexible circuit board in the embodiment solves the problem of interlayer dislocation, and the secondary outer circuit layers L21 and L24 are optical layers and have no circuit. The two outermost circuit layers L21 and L24 are positioned according to the target layers of the inner circuit layer L22 and the circuit layer L23, the large copper sheet is arranged before the outer layer lamination, the positioning can be performed according to the target layers of the inner circuit layer L22 and the circuit layer L23 after the lamination, the outer layers can be changed together after the expansion and the contraction of the target layers, and the problem of layer deviation caused by displacement and expansion and contraction is effectively solved.

Compared with the original core plate, pure glue and core plate lamination, the embodiment is structurally changed into lamination of a plurality of flexible core plates, wherein the lamination is performed in a mode of the core plate, the pure glue, the core plate, the pure glue and the core plate, the L22/L23 layer patterns are firstly formed on the middle flexible core plate, then the two outer flexible core plates are etched into a single face, and the middle is laminated through the pure glue, at the moment, the two outer core plates have no inner layer patterns, and interlayer dislocation is not caused even if lamination shifts. In addition, the inner layer needs to be filled with the single-sided adhesive of the pure adhesive bonding layer, so that the filling can be effectively and fully performed, and the lamination cavity is avoided. Solves the defects of unreasonable laminating and filling glue and hollowness of the original lamination. The abnormalities such as dislocation between layers, incomplete glue filling, layered explosion plate and the like are effectively avoided. The thickness of the cover film and the cover plate in this embodiment is the same as in the first embodiment.

As shown in fig. 4, the four-layer flexible wiring board manufactured by the above-mentioned four-layer flexible wiring board manufacturing method is formed by laminating, in order from top to bottom, a cover film 211, a wiring layer L21, a dielectric layer 221, an adhesive layer 231, a wiring layer L22, a dielectric layer 222, a wiring layer L23, an adhesive layer 232, a dielectric layer 223, a wiring layer L24, and a cover film 212.

When manufacturing the flexible circuit board with more layers, the principle that the circuit layer of the double-sided core board and the adhesive layer are manufactured firstly and then the covering film and the circuit layer of the single-sided core board are manufactured in the four-layer flexible circuit board manufacturing method can be referred to, and the specific steps are not repeated here.

The manufacturing method of the four-layer flexible circuit board is also suitable for manufacturing flexible circuit boards with more layers. The multi-layer flexible circuit board manufactured by the method consists of two layers of covering films, two single-sided core boards, a plurality of double-sided core boards and an adhesive bonding layer; the single-sided core board consists of a circuit layer and a medium layer, and the double-sided core board consists of the circuit layer, the medium layer and the circuit layer in sequence; the covering films are arranged on the upper surface and the lower surface, the circuit layer of the single-sided core plate is adjacent to the covering films, the medium layer is adjacent to the circuit layer of the double-sided core plates, and the adhesive bonding layer is arranged between the two adjacent double-sided core plates.

The above description is only of the preferred embodiments of the present patent and is not intended to limit the present patent, and various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present patent should be included in the protection scope of the present patent.

Claims

1. The manufacturing method of the multilayer flexible circuit board is characterized by comprising the following steps:

s11: cutting to provide two core plates;

s14: laminating the cover film 112 and the circuit layer L12 or L13;

s17: the materials were arranged in the following order from top to bottom: cover plate 14, line layer L11, dielectric layer 121, line layer L12, cover film 112, adhesive layer 131, line layer L13, dielectric layer 122, line layer L14, cover plate 14 or cover plate 14, line layer L11, dielectric layer 121, line layer L12, adhesive layer 131, cover film 112, line layer L13, dielectric layer 122, line layer L14, cover plate 14;

s18: laminating and riveting: rivet 15 is added in the riveting hole;

s110: taking two cover plates 14;

s112: the cover films 111 and 113 are manufactured in the same steps as S13, and the cover film 111 is disposed on the circuit layer L11, and the cover film 113 is disposed under the circuit layer L14 and laminated.

2. The method for manufacturing a multilayer flexible wiring board according to claim 1, wherein: the thickness of the covering film is 15-70UM.

3. The method for manufacturing a multilayer flexible wiring board according to claim 1, wherein: the thickness of the cover plate is 0.2-1.0 mm.