KR102425900B1 - Manufacturing method of double side flexible printed circuit board - Google Patents

Abstract

The present invention relates to a method for manufacturing a double-sided flexible printed circuit board, comprising the steps of applying an insulating material to a master mold, removing a portion corresponding to a terminal portion from the applied insulating material, and plating the master mold with a first conductive material to form a terminal portion on a portion from which the insulating material is removed, removing a portion corresponding to the circuit pattern from the applied insulating material, and plating a second conductive material on the master mold to form the circuit pattern , attaching an insulating film between two master molds on which circuit patterns are formed, separating a double-sided flexible printed circuit board on which circuit patterns are laminated on both sides of the insulating film in the two master molds, the double-sided flexible Connecting circuit patterns on both sides of the printed circuit board to each other and attaching an insulating film having an opening to each of the circuit patterns on both sides of the double-sided flexible printed circuit board.

Description

Manufacturing method of double-sided flexible printed circuit board {MANUFACTURING METHOD OF DOUBLE SIDE FLEXIBLE PRINTED CIRCUIT BOARD}

The present invention relates to a method for manufacturing a double-sided flexible printed circuit board in which a circuit board is formed on both sides of an insulating film.

Flexible Printed Circuit Board (FPCB) is a board that can be flexibly bent by forming a circuit pattern on a thin insulating film. It is widely used in mobile devices and display devices.

Such flexible printed circuit boards are generally manufactured using a copper clad laminate (FCCL), in which a copper clad layer is laminated on a polyimide film layer, as a substrate (raw material), and laminated, exposed, developed, A method of forming a circuit pattern by performing an operation such as etching is mainly used.

On the other hand, when manufacturing a double-sided flexible printed circuit board to perform circuit connection on both sides of the flexible printed circuit board, a double-sided FCCL substrate is generally used. to be.

Through-holes are formed in these double-sided FCCLs, and the copper foil layers on both sides are electrically connected by plating or the like to enable circuit connection on both sides of the flexible printed circuit board.

In the case of using double-sided FCCL to manufacture a double-sided flexible printed circuit board, a method of forming a circuit pattern by performing operations such as laminating, exposing, developing, and etching on a copper clad laminate is used.

Meanwhile, the background technology of the present invention is disclosed in Korean Patent Laid-Open No. 10-2018-0016323 (2018.02.14).

In the case of the conventional method of manufacturing a flexible printed circuit board using FCCL, since a circuit pattern is formed through an etching process, there is a problem that the width of the gap in the vertical direction may not be constant when a gap between circuits is formed. do.

In addition, when forming the terminal portion by performing gold plating or the like after forming the circuit pattern, there is a problem in that a process for plating only a desired area becomes complicated.

The present invention is to solve the problems of the conventional double-sided flexible printed circuit board manufacturing method using the double-sided FCCL as described above, and it is easier to control the pattern thickness compared to the conventional method and to reduce the manufacturing cost. An object of the present invention is to provide a method for manufacturing

A method for manufacturing a double-sided flexible printed circuit board according to the present invention comprises the steps of applying an insulating material to a master mold; removing a portion corresponding to the terminal portion from the applied insulating material: forming a terminal portion on the portion from which the insulating material is removed by plating the master mold with a first conductive material; removing a portion corresponding to the circuit pattern from the applied insulating material; forming the circuit pattern by plating a second conductive material on the master mold; attaching an insulating film between two master molds on which circuit patterns are formed; separating the double-sided flexible printed circuit board on which circuit patterns are laminated on both sides of the insulating film in the two master molds; connecting circuit patterns on both sides of the double-sided flexible printed circuit board to each other; and attaching an insulating film having an opening to each of the circuit patterns on both sides of the double-sided flexible printed circuit board.

In the present invention, the forming of the terminal part may include plating the first conductive material on the master mold and then plating the third conductive material.

In the present invention, the first conductive material is gold, the second conductive material is copper, the third conductive material is nickel, the insulating material is an insulating material, and the insulating film is a polyimide film. .

The present invention is characterized in that it further comprises the step of removing the remaining portion of the applied insulating material after the step of forming the circuit pattern.

In the present invention, the step of connecting the circuit patterns on both surfaces to each other may include forming at least one via hole in the circuit patterns on both surfaces.

In the present invention, the circuit pattern is characterized in that it is formed to a thickness of 3um to 250um.

The double-sided flexible printed circuit board manufacturing method according to the present invention has the effect of making it possible to manufacture a double-sided flexible printed circuit board having the same shape as a double-sided flexible printed circuit board manufactured using double-sided FCCL without going through an etching process.

In addition, the method for manufacturing a double-sided flexible printed circuit board according to the present invention has the effect of reducing the manufacturing cost of the double-sided flexible printed circuit board by allowing plating of only a desired area to be easily performed when gold is plated on the terminal portion. have.

1 is a flowchart illustrating a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention.
2 to 10 are exemplary views for explaining a method of manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention.

Hereinafter, an embodiment of a method for manufacturing a double-sided flexible printed circuit board according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, definitions of these terms should be made based on the content throughout this specification.

1 is a flowchart for explaining a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention, and FIGS. 2 to 10 are for explaining a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention As an exemplary view, a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention will be described with reference to this.

2 to 10, only the cross-section of the board is shown to explain the manufacturing process of the double-sided flexible printed circuit board, and the implementation of a typical circuit pattern, such as a circuit pattern in which the circuit pattern is connected in a circle, is widely known in the technical field of the present invention Therefore, a detailed description thereof will be omitted.

As shown in FIG. 1 , in the method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention, urethane 2 is first applied to the master mold 1 ( S10 ). That is, as shown in FIG. 2, according to the plating method, urethane 2, which is not plated unlike the master mold 1, is applied to the master mold 1 to form an insulating coating layer, so that plating of only the desired area is performed. make it possible to perform At this time, the urethane (2) may be applied to a thickness of 3um ~ 250um.

Meanwhile, in the case of the master mold 1, it may be composed of SUS (stainless steel), etc., but in addition, it may be composed of various materials capable of performing smooth plating.

In this embodiment, it has been described that urethane is used as the insulating coating layer, but in addition, the insulating coating layer may be formed using a urethane mixture (a mixture of urethane and acrylic), Teflon, or the like.

Next, the portion 3 corresponding to the terminal portion is removed from the applied urethane 2 (S20). That is, as shown in FIG. 3 , only the area desired for plating is removed from the applied urethane 2 , so that plating can be performed only on the area corresponding to the terminal part.

Removal of the urethane 2 may be configured such that only the desired area is removed, for example by means of a laser. That is, by irradiating a laser beam on the surface of the master mold 1 on which the urethane 2 is laminated, the urethane 2 in the corresponding area can be removed. At this time, the removal of the urethane (2) may be performed to a thickness of 3um ~ 250um corresponding to the thickness of the urethane (2). That is, by adjusting the output specifications (power, frequency, etc.) of the laser, the removal of the urethane 2 is performed, but the master mold 1 can be not affected.

After the step (S20), gold and nickel are plated to form the terminal portions 4 and 5 (the first terminal portion) (S30). That is, in the manufacturing process of the flexible printed circuit board, gold and nickel portions, not circuit patterns, are first formed, but the shape of the urethane 2 is controlled in a relatively easy manner so that plating is performed only on the desired portions.

For example, a method of placing the master mold 1 in a tank filled with a solution for plating, etc., and performing plating by an electroplating method may be used. At this time, unlike the surface of the master mold 1, plating is not performed on the portion where the insulating urethane 2 is laminated.

Alternatively, electroless plating may be performed, but the plating may be performed only on the master mold 1 by selecting a catalyst according to the physical properties of the master mold 1 and the insulating coating layer (urethane 2 ).

In this embodiment, the configuration of the apparatus for performing the plating process or the specific plating method corresponds to a technique well known in the technical field of the present invention, and since various embodiments are available, a more detailed description will be omitted.

At this time, as shown in FIG. 4 , gold 4 is first plated and then nickel 5 is plated so that the terminal portion made of gold 4 is exposed as an outer shell.

Then, a portion corresponding to the circuit pattern is removed from the applied urethane 2 (S40), and the circuit pattern 6 is formed by plating copper (S50). That is, similarly to the above-described steps (S20) and (S30), the shape of the urethane 2 may be deformed so that plating is performed only on a desired area. As shown in FIG. 5 , the circuit pattern 6 is plated on the remaining area after the terminal portions 4 and 5 are formed to form the terminal portions 4 and 5 on the circuit pattern 6 .

The thickness of the circuit pattern 6 to be plated may be made within the thickness of the urethane 2, and may have a thickness of 3 μm to 250 μm.

Meanwhile, in this embodiment, the first conductive material is gold, the second conductive material is copper, and the third conductive material is nickel. could also be used.

In addition, the plating method of each conductive material may be different from each other.

After the step (S50), the remaining portion of the applied urethane 2 is removed (S60). That is, when the terminal portions 4 and 5 and the circuit pattern 6 are plated, the residual urethane 2 that is no longer needed as shown in FIG. 6 can be removed.

Then, as shown in FIG. 7, an insulating film 7 is attached between the two master molds 1 and 1' on which the circuit patterns 6 and 6' are formed (S70). That is, the two master molds 1 and 1 ′ performed up to the step S60 are prepared, and an insulating film 7 is attached therebetween so that a circuit pattern is formed on both sides of the insulating film 7 . can

The insulating film 7 may be, for example, a polyimide film, but may also be a film made of another insulating material.

Such an insulating film 7 may be attached between the circuit patterns 6 and 6 in an adhesive manner, for example, by laminating an adhesive layer on the circuit patterns 6 and 6' or applying an adhesive and then applying the insulating film 7 to the circuit patterns 6 and 6'. A method of attaching the insulating film 7 provided with an adhesive layer or an adhesive between the circuit patterns 6 and 6 ′ may be used, and a thermosetting adhesive or an adhesive sheet may be utilized. In addition, at this time, a press operation for bonding may be performed.

After the step (S70), the double-sided flexible printed circuit board is separated from the master molds 1 and 1' (S80). Since the circuit patterns 6 and 6 ′ were laminated on both sides of the insulating film 7 according to the above-described step S70 , as shown in FIG. 8 , the two master molds 1 and 1 ′ were separated and both sides were separated. A flexible printed circuit board can be obtained.

This separation process may be performed by peeling the product from the master molds 1 and 1 ′, and a mechanical method, a chemical method, or an electrochemical method may be selected as needed.

On the other hand, in some embodiments, the urethane-coated master mold ( A method of separating only the two circuit patterns 6 and 6 ′ laminated on the insulating film 7 from 1, 1 ′ may be used.

Subsequently, a via hole 8 is formed in the obtained double-sided flexible printed circuit board (S90). For example, as shown in FIG. 9, for the connection of the circuit patterns 6, 6' and/or the terminal parts 4, 5, 4', 5' on both sides, the desired location is selected through a drilling process. A hole may be formed through the hole, and a conductive material may be plated on the hole so that the circuit patterns 6 and 6' and/or the terminal parts 4, 5, 4' and 5' on both sides are connected to each other. .

However, since the formation of the via hole 8 can be used as it is in the conventional double-sided printed circuit board manufacturing method using the double-sided FCCL substrate, a more detailed description thereof will be omitted.

In addition, in some embodiments of the present invention, various other known methods for connecting the circuit patterns 6 and 6' and/or the terminal parts 4, 5, 4' and 5' on both sides to each other may be used.

Thereafter, insulating films 9 and 9' having openings corresponding to the terminal portions are attached to each of the two circuit patterns 6 and 6' of the double-sided flexible printed circuit board (S100).

Accordingly, as shown in FIG. 10, insulating films 9 and 9' are laminated on each of the circuit patterns 6 and 6', and openings corresponding to the terminal portions are formed in the insulating films 9 and 9'. Since is formed, circuit connection is possible to the terminal part from both sides.

That is, the openings formed in the insulating films 9 and 9' allow the terminal portions to be exposed, thereby enabling the connection of circuits or devices.

The openings formed in the insulating films 9 and 9 ′ may have various shapes such as a hole shape or a rectangular shape depending on the printed circuit board to be manufactured, and a plurality of openings may be formed, and may be additionally formed in addition to the terminal part. .

Here, the insulating films 9 and 9' may be, for example, polyimide films, but may also be films of other insulating materials. In addition, the insulating films 9 and 9' respectively laminated on the circuit patterns 6 and 6' may be made of different materials.

Thereafter, the product may be completed through a hot press operation or the like, and the subsequent process may be the same as a conventional manufacturing method of a flexible printed circuit board.

After this process, the part can be mounted using the terminal part of the opening formed on both sides as a contact point.

A conductive connection member may be used between these parts and the exposed terminal part, and for example, a conductive adhesive, conductive cream, solder, etc. may be used.

The flexible printed circuit board manufactured in this way can be completed as a product through external processing such as altar.

Between the above-described processes, additional processes (eg, washing processes, drying processes, etc.) for product production may be added as needed.

On the other hand, the present invention can be carried out in a flexible printed circuit board manufacturing facility configured to perform each process such as coating, laser irradiation, plating, attaching, peeling, drilling, and the like, and the control device of the manufacturing facility controls the operation of each process. can be controlled Such a manufacturing facility may additionally include a robot arm, a conveying belt, etc. for conveying products between each process, and various equipment may be added in addition. In addition, the control device may include a computer-readable storage medium for storing instructions for controlling the manufacturing equipment to perform each process, and the storage medium is combined with the processor to cause the processor to perform each step of the present invention. can be

Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and those of ordinary skill in the art to which various modifications and equivalent other embodiments are possible. will understand Therefore, the technical protection scope of the present invention should be defined by the following claims.

1: master mold
2: Urethane
3: Terminal area
4, 4`, 5, 5`: terminal part
6, 6: Circuit pattern
7: insulating film
8: via hole
9, 9`: insulating film

Claims (6)

applying an insulating material to the master mold;
removing the portion corresponding to the terminal portion from the applied insulating material:
plating a first conductive material on the master mold to form a terminal portion on a portion from which the insulating material is removed;
removing a portion corresponding to the circuit pattern from the applied insulating material;
forming the circuit pattern by plating a second conductive material on the master mold;
attaching an insulating film between two master molds on which circuit patterns are formed;
separating the double-sided flexible printed circuit board on which circuit patterns are laminated on both sides of the insulating film in the two master molds;
connecting circuit patterns on both sides of the double-sided flexible printed circuit board to each other; and
and attaching an insulating film having an opening to each of the circuit patterns on both sides of the double-sided flexible printed circuit board.
According to claim 1,
The forming of the terminal part comprises plating the first conductive material on the master mold and then plating the third conductive material.
3. The method of claim 2,
wherein the first conductive material is gold, the second conductive material is copper, the third conductive material is nickel, the insulating material is urethane, and the insulating film is a polyimide film. Substrate manufacturing method.
According to claim 1,
After forming the circuit pattern,
The method for manufacturing a double-sided flexible printed circuit board, characterized in that it further comprises the step of removing the remaining portion of the applied insulating material.
According to claim 1,
The step of connecting the circuit patterns on both sides to each other,
and forming at least one via hole in the circuit pattern on both sides.
According to claim 1,
The circuit pattern is a double-sided flexible printed circuit board manufacturing method, characterized in that formed to a thickness of 3um to 250um.

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