A method for manufacturing a high shielding flexible board and a high shielding flexible board

Abstract

The application discloses a manufacturing method of a high-shielding flexible plate and the high-shielding flexible plate, and provides the flexible plate, which comprises a first film layer, a circuit copper layer and a second film layer, and the first film layer and the second film layer are respectively arranged on the upper and lower surfaces of the circuit copper layer; the flexible plate is subjected to roughening treatment; a silver paste pattern layer is screen-printed on the first film layer, and baking and curing are carried out; a third film layer is attached to the silver paste pattern layer after curing, and rapid pressing is carried out to form the high-shielding flexible plate. The silver paste pattern layer with high shielding characteristics is manufactured on the film layer, and another film layer is manufactured on the silver paste pattern layer to form a good double-layer pattern and double-layer film layer structure, and a reliable process manufacturing method is formed, the high shielding characteristics can be effectively realized, the flexibility of the flexible circuit board itself is not affected, and the flexible plate with high shielding performance can be provided for connectors and high-precision instruments.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit board manufacturing, in particular to a high shielding flexible board manufacturing method and a high shielding flexible board. BACKGROUND

[0002] For some flexible boards applied in connectors and high-precision instruments, they need to have good electromagnetic shielding performance.

[0003] At present, a film layer or a composite film layer (for example, a polyimide layer + an aluminum foil layer + a polyimide layer) with electromagnetic shielding performance is arranged in an area that needs to have good electromagnetic shielding performance, and is subjected to pressing and various process processing to form a shielding structure and achieve a shielding effect.

[0004] However, the film layer or the composite film layer with electromagnetic shielding performance generally has a high cost, which is not conducive to batch production and application of the flexible board, and such a film layer has a high requirement on the processing technology and needs to realize effective matching between various materials, so a large amount of manpower, materials and time cost needs to be invested in processing, which does not meet the demand of low cost and high efficiency processing for general flexible boards.

[0005] Based on the above background, it is necessary to provide a low-cost high shielding flexible board manufacturing method that can be effectively applied to batch flexible board processing. SUMMARY

[0006] The main purpose of the present application is to provide a high shielding flexible board manufacturing method and a high shielding flexible board, which aims to solve the problems of high processing difficulty and high manufacturing cost of the existing flexible board with electromagnetic shielding performance.

[0007] To achieve the above purpose, the present application provides a high shielding flexible board manufacturing method, which comprises the following steps:

[0008] A flexible board is provided, which comprises a first film layer, a circuit copper layer and a second film layer, and the first film layer and the second film layer are respectively located on the upper and lower surfaces of the circuit copper layer;

[0009] The flexible board is subjected to roughening treatment;

[0010] A silver paste pattern layer is screen printed on the first film layer, and baking and curing are performed;

[0011] After curing, a third film layer is attached to the silver paste pattern layer, rapid pressing is performed, and a high shielding flexible board is formed.

[0012] Further, the flexible board is formed by process processing based on the circuit copper layer as a basic layer, and the process processing comprises the following steps:

[0013] The circuit copper layer is provided, the first film layer is attached to one side of the circuit copper layer, and fast pressing treatment is performed to form a single-sided flexible board;

[0014] The single-sided flexible board is subjected to graphic processing treatment to form a single-sided graphic flexible board;

[0015] The second film layer is attached to the single-sided graphic flexible board, and fast pressing treatment is performed to form the flexible board.

[0016] Further, the first film layer is composed of a first adhesive layer and a first cover film layer; the second film layer is composed of a second adhesive layer and a second cover film layer; the first adhesive layer or the second adhesive layer is a polyolefin adhesive layer or an epoxy resin adhesive layer or an acrylic adhesive layer.

[0017] Further, the third film layer is formed by laminating a third adhesive layer and a third cover film layer, the laminating manner is that a third adhesive layer is formed by silk printing or coating glue on the silver paste pattern layer, pre-baking is performed at parameters of 75 DEG C x 35 min to 45 min, the third cover film layer is attached, fast pressing treatment is performed, and post-curing baking is performed at parameters of 120 DEG C x 35 min to 45 min.

[0018] Further, the third adhesive layer is a polyolefin adhesive layer or an epoxy resin adhesive layer or an acrylic adhesive layer, and the glue viscosity of the silk printing or coating glue is 130-170 dpa.s.

[0019] Further, the length of the third film layer is less than the length of the first film layer, and the width of the third film layer is less than or equal to the width of the first film layer; the thickness of the third adhesive layer is greater than the silver paste pattern layer.

[0020] Further, the silver paste pattern layer is an "S" shape circuit pattern, and the circuit width of the "S" shape circuit pattern is 0.5 mm to 2.5 mm.

[0021] Further, the silver paste pattern layer is a mesh circuit pattern, and the circuit width of the mesh circuit pattern is 0.3 mm to 2.0 mm.

[0022] Further, the high shielding flexible board further comprises a second shielding structure, the second shielding structure is made on the second film layer, and the second shielding structure is symmetrical to the structure composed of the silver paste pattern layer and the third film layer.

[0023] To achieve the above object, the application provides a high shielding flexible board made by the manufacturing method.

[0024] In the technical scheme, the high shielding flexible plate manufacturing method adopts film layer manufacturing on the flexible circuit board, and silver paste pattern layer manufacturing on the film layer, can effectively form a shielding layer by using the good shielding characteristics of silver paste, and then another film layer is used to protect the silver paste pattern layer to form a double film layer flexible circuit board, which can effectively realize the high shielding characteristics, and does not affect the flexibility of the flexible circuit board itself, and can provide a high shielding performance flexible circuit board for connectors and high-precision instruments. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the drawings shown.

[0026] Figure 1 The process flow diagram of the manufacturing method of the high shielding flexible plate of the present application;

[0027] Figure 2 The structure diagram of one embodiment of the high shielding flexible plate of the present application;

[0028] Figure 3 The structure diagram of another embodiment of the high shielding flexible plate of the present application;

[0029] Figure 4 The "S" shape line pattern diagram of the silver paste pattern layer of the present application;

[0030] Figure 5 The mesh line pattern diagram of the silver paste pattern layer of the present application;

[0031] Figure 6 The structure diagram of the high shielding flexible plate of the present application containing a second shielding structure.

[0032] Explanation of reference numerals:

[0033] Reference Name Reference Name 10 High shielding flexible board 300b Second cover film layer 100 Circuit copper layer 400 Silver paste pattern layer 200 First film layer 500 Third film layer 200a First glue layer 500a Third glue layer 200b First cover film layer 500b Third cover film layer 300 Second film layer 20 Second shielding structure 300a First glue layer / /

[0034] The implementation, functional characteristics and advantages of the present application will be further described with reference to the embodiments and drawings. DETAILED DESCRIPTION

[0035] Clearly and completely, the technical solutions in the embodiments of the present application will be described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0036] It should be noted that all directional indications, such as up, down, left, right, front, back, etc., in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0037] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through intermediate medium; can be internal communication of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection required by the present application.

[0040] The rigid-flex combined board manufacturing method of the embodiment focuses on the layout and pressing process in this flow.

[0041] Please refer to Figure 1 、 Figure 2 , Figure 1 for the process flow diagram of the manufacturing method of a high shielding flexible board of the present application; Figure 2 for the structural diagram of an embodiment of a high shielding flexible board of the present application.

[0042] As Figure 2As shown, the high-shield flexible plate 10 in this embodiment is composed of... Figure 1 The high-shield flexible board 10 is manufactured by the following method. It is processed on the basis of a flexible board. The flexible board includes a first film layer 200, a circuit copper layer 100, and a second film layer 300. The first film layer 200 and the second film layer 300 are located on the upper and lower surfaces of the circuit copper layer 100, respectively. The basic steps of manufacturing the high-shield flexible board based on the flexible board include roughening the flexible board, screen printing a silver paste pattern layer 400 on the first film layer 200, baking and curing it, attaching a third film layer 500 on the cured silver paste pattern layer 400, and quickly pressing it together to form the high-shield flexible board 10.

[0043] Since the surface of the flexible board is relatively smooth, that is, the surfaces of the first film layer 200 and the second film layer 300 are relatively smooth, it is necessary to roughen the flexible board. Since the materials of the first film layer 200 and the second film layer 300 are generally highly inert, they are difficult to react with ordinary chemical solutions. Therefore, plasma roughening treatment is generally used here. Plasma roughening treatment can utilize the plasma environment to effectively form a roughened surface on the surface of the highly inert material, which is beneficial for the silver paste pattern layer 400 to be better fabricated on the first film layer 200.

[0044] After roughening, silver paste needs to be applied to the first film layer 200. If the silver paste is applied to the entire surface of the first film layer 200, it will affect the flexibility of the flexible board and may cause problems such as silver paste surface breakage during the bending process. In addition, the cost of applying the entire surface is high. Therefore, the silver paste needs to be made into a circuit pattern and the silver paste pattern layer 400 is made by screen printing, which can effectively control the accuracy, thickness, shape and other parameters of the silver paste pattern.

[0045] After screen printing the silver paste graphic layer 400, the silver paste graphic layer needs to be cured. Generally, silver paste refers to a paste compound system of silver powder mixed with polymer resin. Therefore, baking curing can effectively promote the thermal curing reaction of polymer resin and allow the volatile solvents in the compound system to evaporate, forming the cured silver paste graphic layer.

[0046] After the silver paste pattern layer 400 is cured, a third film layer 500 needs to be attached to its surface to protect the silver paste pattern layer 400 and provide a reliable basis for the flexible board's flexural performance.

[0047] In the embodiment, the flexible board takes the circuit copper layer 100 as a basic layer to be processed in a flow, that is, the first film layer 200 is attached to one side of the circuit copper layer 100 and fast pressing treatment is performed to form a single-sided flexible board; the circuit copper layer 100 is processed to form a required circuit pattern, the second film layer 300 is attached, and fast pressing treatment is performed to form a flexible board; the flexible board formed here is a structure of the double-sided film layer covering the circuit copper layer 100, and is not a structure of the double-sided copper layer covering the film layer of the common copper-clad plate.

[0048] Please refer to Figure 3 , Figure 3 is a structure diagram of another embodiment of the high shielding flexible board of the present application; in the embodiment, the first film layer 200 is composed of a first adhesive layer 200a and a first cover film layer 200b, and the second film layer 300 is composed of a second adhesive layer 300a and a second cover film layer 300b; the film layer is arranged in the form of the adhesive layer and the cover film layer to effectively fill the gap of the circuit pattern with the adhesive layer and increase the adhesion of the cover film layer and the circuit layer with the adhesive layer to prevent the problems of the cavity and delamination of the circuit board.

[0049] Please refer to Figure 3 , in the embodiment, the third film layer 500 is formed by laminating the third adhesive layer 500a and the third cover film layer 500b; the laminating method is to print or coat the adhesive on the silver paste pattern layer 400 to form the third adhesive layer 500a, pre-bake at 75℃×35min to 45min, attach the third cover film layer 500b, and perform fast pressing treatment, and post-curing baking at 120℃×35min to 45min.

[0050] The third film layer 500 is also provided as a laminated structure of a glue layer and a cover film layer. Since the silver paste pattern layer 400 also has a circuit pattern and the silver paste circuit is on the copper layer circuit of the flexible board itself, the bonding force between the silver paste circuit and the cover film material is weaker, and the cover film needs to be covered more, so the third glue layer 500a can effectively fill the circuit gap of the silver paste pattern layer 400 and effectively improve the bonding force between the effective protection film layer and the silver paste pattern layer 400 and the first film layer 200. The third glue layer 500a is made by silk printing or coating, which can effectively control the range, thickness, coverage effect and other factors of the third glue layer 500a. After the third glue layer 500a is silk printed or coated, low temperature and short time baking is adopted, that is, 75°C×35min to 45min, so that the glue layer is semi-cured (not fully cured), which provides a basis for subsequent attachment of the third cover film layer 500b. After the third cover film layer 500b is attached, fast pressing (rapid pressing) is adopted to press and combine the third cover film layer 500b and the third glue layer 500a, so that a good laminated combination effect is formed. Generally, fast pressing adopts a temperature of 120°C to 150°C, a pressure of 50kg / cm 2 to 100kg / cm 2 , and a pressing time of 60 seconds to 70 seconds. After fast pressing, high temperature and short time baking is adopted, that is, 120°C×35min to 45min, to improve the bonding force between the glue layer and the film layer and remove the internal stress of the flexible board.

[0051] It is worth noting that the process of forming the first film layer 200 by laminating the first glue layer 200a and the first cover film layer 200b, and the process of forming the second film layer 300 by laminating the second glue layer 300a and the second cover film layer 300b, can also be formed by laminating the third glue layer 500a and the third cover film layer 500b.

[0052] In this embodiment, the first glue layer 200a, the second glue layer 300a, and the third glue layer 500a can adopt a polyolefin glue layer or an epoxy resin glue layer or an acrylic glue layer, and the viscosity is 130-170dpa.s, which is suitable for silk printing viscosity and can ensure the filling and adhesion effect between layers.

[0053] Please refer to Figure 2 , Figure 3In this embodiment, to prevent the upper cover film from exceeding the coverage area of ​​the lower cover film and causing delamination, the length of the third film layer 500 is set to be less than that of the first film layer 200. However, since the third film layer 500 and the first film layer 200 can be selectively formed simultaneously, the width of the third film layer 500 can be less than or equal to the width of the first film layer 200. As can be seen from the characteristics and functions of the third adhesive layer 500a, the third film layer 500a plays the role of filling the silver paste pattern layer 400. Therefore, setting the thickness of the third adhesive layer 500a to be greater than that of the silver paste pattern layer 400 can achieve a good filling effect and can also prevent the third cover film layer 500b from directly bonding with the silver paste pattern layer 400, thus preventing problems such as poor bonding, delamination, and voids.

[0054] Please see Figure 4 , Figure 5 , Figure 4 This is a schematic diagram of the "S"-shaped circuit pattern of the silver paste pattern layer of the present invention. Figure 5 This is a schematic diagram of the mesh circuit pattern of the silver paste pattern layer of the present invention.

[0055] Using a silver paste pattern layer 400 as a high shielding layer is problematic because directly covering the entire surface of the first film layer 200 with silver paste can easily lead to poor adhesion of the third film layer 500, and the silver paste layer is prone to cracking during subsequent bending. Furthermore, the cost of using silver paste is relatively high. Therefore, a screen printing method is used to create a pattern of silver paste on the first film layer, which effectively provides shielding, facilitates the elastic bending of the silver paste pattern, and saves on silver paste material costs. In this embodiment, the silver paste pattern layer 400 can be designed as an "S"-shaped circuit pattern with a line width of 0.5mm to 2.5mm; or it can be designed as a mesh circuit pattern 400b with a line width of 0.3mm to 2.0mm.

[0056] Please see Figure 6 , Figure 6 This is a schematic diagram of a high-shield flexible plate containing a second shielding structure according to the present invention. If the flexible plate itself requires a double-sided high shielding effect to form a more tightly sealed shielding environment, the same method and structure can be used to fabricate a second shielding structure 20 on the other side of the flexible plate; the second shielding structure 20 is fabricated on the second film layer 300, and the second shielding structure 20 is symmetrical to the structure composed of the silver paste pattern layer 400 and the third film layer 500.

[0057] This embodiment uses the above manufacturing method to obtain a flexible board with high shielding performance.

[0058] In the embodiment, the flexible plate structure is made by clamping the copper layer of the circuit with the cover film, which is beneficial to the subsequent high shielding circuit layer of the silver paste pattern layer. The silver paste pattern layer is made on the cover film layer, the flexible plate has high shielding effect by using the good electromagnetic shielding characteristics of the silver paste, the silver paste layer is protected by another cover film, and the structure of the double-layer cover film and double-layer pattern (copper layer circuit pattern and silver paste layer circuit pattern) is formed. Without affecting the flexibility of the flexible plate, the flexible plate has good shielding effect.

[0059] The manufacturing process of the embodiment is based on various factors such as manufacturing quality, cost, structural characteristics, and effect characteristics, to form an overall manufacturing process. The overall process is connected to each other, and is related to each other. The expansion and contraction characteristics of the cover film, the filling and adhesion characteristics of the adhesive layer, and the silk printing and shielding characteristics of the silver paste layer are fully utilized. The process features of the complex structure of multiple materials are formed, which can provide good high shielding flexible plate products for the electronic information industry mainly based on connectors.

[0060] The above description is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or direct / indirect application in other related technical fields under the inventive concept of the present application are included in the patent protection scope of the present application.

Claims

1. A method of manufacturing a high shielding flexible board, characterized by, The manufacturing method comprises: providing a circuit copper layer, attaching a first film layer to one side of the circuit copper layer, and performing first rapid pressing to form a single-sided flexible board; performing pattern processing on the single-sided flexible board to form a single-sided patterned flexible board; attaching a second film layer to the single-sided patterned flexible board and performing second rapid pressing to form a flexible board; the flexible board comprises a first film layer, a circuit copper layer, and a second film layer, and the first film layer and the second film layer are respectively located on the upper and lower sides of the circuit copper layer; the first film layer is composed of a first adhesive layer and a first cover film layer; the second film layer is composed of a second adhesive layer and a second cover film layer; the first adhesive layer or the second adhesive layer is a polyolefin adhesive layer or an epoxy resin adhesive layer or an acrylic adhesive layer; performing plasma roughening on the flexible board; silk-screening a silver paste pattern layer on the first film layer and performing baking and curing; the silver paste pattern layer is an "S"-shaped circuit pattern or a mesh circuit pattern; attaching a third film layer to the silver paste pattern layer after curing, the third film layer being formed by laminating a third adhesive layer and a third cover film layer, the lamination processing is performed by silk-screening or coating a gel on the silver paste pattern layer to form the third adhesive layer, pre-baking at a temperature of 75°C for 35-45 minutes, attaching the third cover film layer, and performing third rapid pressing, and post-curing baking at a temperature of 120°C for 35-45 minutes; The third fast pressing uses a temperature of 120°C to 150°C, a pressure of 50kg / cm 2 to 100kg / cm 2 and a pressing time of 60 seconds to 70 seconds. the third adhesive layer is a polyolefin adhesive layer or an epoxy resin adhesive layer or an acrylic adhesive layer, and the gel viscosity of the silk-screening or coating gel is 130-170 dpa.s; the length of the third film layer is less than that of the first film layer, and the width of the third film layer is less than or equal to that of the first film layer; the thickness of the third adhesive layer is greater than that of the silver paste pattern layer; performing rapid pressing again to form a high-shielding flexible board; the high-shielding flexible board further comprises a second shielding structure, the second shielding structure being formed on the second film layer, and the second shielding structure being symmetrical to the structure composed of the silver paste pattern layer and the third film layer.

2. The method of claim 1, wherein the flexible board is a high shielding flexible board. The circuit width of the "S"-shaped circuit pattern is 0.5-2.5 mm.

3. The method of claim 1, wherein the flexible board is a high shielding flexible board. The circuit width of the mesh circuit pattern is 0.3-2.0 mm.

4. A highly shielded flexible board characterized by, The high-shielding flexible board is manufactured by the manufacturing method of any one of claims 1-3.

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