KR20180016323A - Laser processing method for double sided patterning of single side type flexible copper clad laminate and double side type flexible printed circuit board manufacturing method using the same - Google Patents

Abstract

The present invention relates to a laser processing method for double-side patterning of a cross-section FCCL substrate, and a method for manufacturing a double-sided flexible circuit board using the same. The laser processing method comprises: (A) a step of preparing, as a substrate, a cross-section FCCL (10) having a copper foil layer (12) formed on a polyimide film layer (11); (B) a step of arranging ultraviolet transmission glass (20) on a polyimide film layer (11) of the cross-section FCCL (10); and (C) a step of opening a non-open surface of the copper foil layer (12) by irradiating a UV laser to burn and remove a required portion of the polyimide film layer (11) through penetration of the ultraviolet transmission glass (20). In step (C), when the UV laser is irradiated to the cross-section FCCL (10) to be processed, only the polyimide film layer (11) is partially removed to open the copper foil layer (12) and to perform double-sided patterning through a circular (dot-type) laser beam having an increased size by being refracted and diffused by the ultraviolet transmission glass (20). The present invention can improve the quality of a product by preventing or minimizing damage to the copper foil layer due to one-side FCCL substrate side laser processing. A double-side operation can be simply performed. The costs can be reduced. An operation process and time can be saved, and a defect rate can be lowered.

Description

 BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a laser processing method for two-sided patterning of a single-sided FCCL substrate, and a method of manufacturing a double-sided flexible circuit board using the same. 2. Description of the Related Art [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing technique for manufacturing a double-sided flexible circuit board which can be more usefully applied to a back light unit or an antenna series of a flexible circuit board product of a mobile part, More particularly, the present invention relates to a method of manufacturing a substrate, and more particularly, to a method of manufacturing a substrate by applying indirect contact method instead of direct contact with a substrate during laser processing for patterning, In particular, it is possible to prevent or minimize the damage of the copper foil layer due to processing on the substrate side, to improve the quality of the product, and to perform laser processing for double-sided patterning of single-sided FCCL substrate And a method for manufacturing a double-sided flexible circuit board using the same.

2. Description of the Related Art Generally, a flexible printed circuit board (FPCB) is a circuit board on which a complicated circuit is formed on a flexible insulating film. The circuit board is used as a mobile device such as a smart phone requiring flexibility in insertion / , LCDs, and the like.

In order to manufacture such a flexible circuit board, a flexible copper clad laminate (FCCL) in which a copper foil layer is laminated on a polyimide film layer is often used as a base material. Such a copper foil laminated film (FCCL) Layer is patterned through an etching process by a photolithography process to form a circuit.

For example, a double-sided FCCL substrate is used instead of a single-sided FCCL substrate in order to manufacture a double-sided flexible circuit board. The double-sided FCCL is a laminate of copper foil layers on both sides of a polyimide film layer, The copper foil layers on both sides are electrically connected to each other by plating through a copper plating process, and then a dry film is disposed on each of the both-side copper foil layers to form a circuit pattern on both sides through exposure, development and etching .

As described above, double-sided FCCL is used for such a double-sided flexible circuit board. Recently, efforts have been made to fabricate a double-sided flexible circuit board using a single-sided FCCL as a substrate for cost reduction and the like.

However, there are many technical limitations in manufacturing a double-sided flexible circuit board based on single-sided FCCL, and it has a problem in that it takes a long time and a long process time, and also low manufacturing quality.

In addition, although a technique of forming a circuit by simply patterning through processing using a laser is applied to the manufacture of a flexible circuit board, most of them employ a method in which a laser is directly brought into contact with a substrate (raw material) Conventionally, there is a problem that the size of the laser beam can not be controlled and the working time is prolonged due to the overlap of the machining area. Particularly, in the laser machining, damage to the copper foil layer occurs due to direct contact with the substrate (raw material) There is a problem in that the quality of the product is raised or badly affected by the quality of the finished product.

Korean Patent Publication No. 10-2010-0072920 Korean Patent Registration No. 10-1431809

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems and the like, and it is an object of the present invention to provide an indirect contact method instead of direct contact with a substrate during laser processing for patterning, It is possible to reduce the overlapping machining area while shortening the working time. In particular, it is possible to prevent or minimize the damage of the copper foil layer due to the substrate side processing, thereby improving the quality of the product, And a method of manufacturing a double-sided flexible circuit board using the same.

The present invention relates to a method of manufacturing a single-sided copper clad laminate by patterning a single-sided FCCL substrate using a UV laser and an ultraviolet ray transmitting glass, processing only the polyimide film layer in a state in which the laser beam is arbitrarily changed over a wide area using light refraction, There is provided a method of laser processing a two-sided patterning of a single-sided FCCL substrate, which enables open and double-sided patterning, and a method for manufacturing a double-sided flexible circuit board using the same.

The present invention is capable of reducing the number of work processes and greatly shortening the working time by drilling a hole for forming a via hole and reducing the copper plating process for filling a copper plating layer on the via hole side by performing a drilling process for forming a via hole And a method for manufacturing a double-sided flexible circuit board using the single-sided FCCL-based double-sided patterning method, thereby improving the product quality while reducing the defect rate as well as cost reduction.

In order to accomplish the above object, there is provided a laser machining method for two-sided patterning of a single-sided FCCL substrate according to the present invention is a laser machining method for double-sided patterning of a single-sided FCCL substrate, (A) providing a substrate with a cross-sectional FCCL (10) having a copper foil layer (12) formed on a polyimide film layer (11); (B) disposing an ultraviolet transmitting glass (20) on the polyimide film layer (11) of the cross-sectional FCCL (10); (C) by irradiating a UV laser so as to penetrate the ultraviolet transmitting glass (20) to burn and remove a necessary part of the polyimide film layer (11) to open the unopened side of the copper foil layer (12) (B) is performed by performing a patterning process to form a terminal or a circuit on the FCCL (10) side of the FCCL (10), wherein the ultraviolet transmitting glass (20) Quartz Glass) or synthetic quartz glass (Fused Silica); In the step (C), the UV laser is irradiated to the single-side FCCL 10 and patterned for forming a terminal or a circuit. The patterned laser beam is refracted and diffused by the ultraviolet transmission glass 20, dot pattern laser beam to remove the polyimide film layer 11 to thereby open the copper foil layer 12 and pattern it.

Here, in the step (B), an ultraviolet ray transmitting glass 20 having a thickness of 0.5 to 1.5 mm is used; In the step (C), a UV laser having a wavelength of 320 to 400 nm is used.

In order to achieve the above object, there is provided a method of manufacturing a double-sided flexible circuit board using a laser processing method for double-sided patterning of a single-sided FCCL substrate according to the present invention, A method for manufacturing a double-sided flexible circuit board, comprising the steps of: (A) providing a substrate with a cross-sectional FCCL 10 having a copper foil layer 12 formed on a polyimide film layer 11; (B) forming a pattern circuit through a photolithography process of disposing a dry film on the open copper foil layer 12 of the cross-section FCCL 10, exposing, developing and etching; (C) disposing an ultraviolet ray transmitting glass (20) on the polyimide film layer (11) disposed on the upper surface of the resultant product after the step (B); (D) A UV laser is irradiated on the polyimide film layer 11 to process a non-processed surface of the single-sided FCCL 10, and the UV-transparent glass 20 is irradiated to burn a necessary portion of the polyimide film layer 11 Thereby forming a terminal or a circuit pattern on the side of the substrate FCCL 10 by performing a patterning process on the side of the substrate FCCL 10 by opening the non-open face of the copper foil layer 12, Wherein the ultraviolet transmitting glass (20) is quartz glass or synthetic quartz glass (Fused silica); In the step (D), the UV laser is irradiated to the single-side FCCL 10 and patterned for forming a terminal or a circuit, the laser beam is refracted and diffused by the ultraviolet transmitting glass 20, dot pattern laser beam to remove the polyimide film layer 11 to thereby open the copper foil layer 12 and pattern it.

Here, in the step (C), an ultraviolet ray transmitting glass 20 having a thickness of 0.5 to 1.5 mm is used; In the step (D), a UV laser having a wavelength of 320 to 400 nm is used.

According to the present invention, it is possible to prevent or minimize the damage of the copper foil layer due to the laser processing and to minimize the defect rate of the product by applying the indirect contact method instead of the direct contact method with the substrate during laser processing for patterning the substrate And the quality of the product can be improved. Also, the laser beam size for the UV laser irradiated using the refraction of light can be diffused and expanded and controlled through the grafting of the ultraviolet transmitting glass and the proper configuration, By adjusting the size of the beam, it is possible to reduce the overlapping working area while reducing the working time compared with the conventional UV laser irradiation method (direct contact method). Can be achieved.

The present invention enables both double-sided patterning of a single-sided copper foil layer to be performed with ease by using single-sided FCCL as a substrate through the coupling of a UV laser and an ultraviolet-transmitting glass, The drilling process and the copper plating process which are widely used for the patterning of the pattern can be omitted, the work process can be shortened and the work time can be greatly reduced, and the cost can be reduced, and also the product quality can be improved Effect can be provided.

INDUSTRIAL APPLICABILITY The present invention can be more effectively applied to a backlight unit or an antenna system, which is a flexible circuit board product group of a mobile part, and performs a jumping or via hole forming process for connection of two sides by terminal patterning It is possible to achieve usefulness to secure price competitiveness in the mobile market.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process flow diagram illustrating a laser processing method for double-sided patterning of a single-sided FCCL substrate in accordance with an embodiment of the present invention.
FIG. 2 is a view for explaining a laser machining method for two-sided patterning of a single-sided FCCL substrate according to an embodiment of the present invention, wherein (a) is a view of a laser machining process showing an indirect contact method according to the present invention, (b) is a comparative drawing of a laser machining process showing a conventional direct contact method.
3 is a view for explaining a laser processing method for double-sided patterning of a single-sided FCCL substrate according to an embodiment of the present invention, wherein (a) is a diagram showing a laser patterning state of an indirect contact type according to the present invention and (b) are comparative diagrams showing the laser patterning state of the conventional direct contact type.
4 is a process flow diagram illustrating a method for fabricating a double-sided flexible circuit board using a laser processing method for double-sided patterning of a single-sided FCCL substrate according to an embodiment of the present invention.
5 is a process diagram showing a method of manufacturing a double-sided flexible circuit board using a laser processing method for double-sided patterning of a single-sided FCCL substrate according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

1 to 3, a laser processing method for double-sided patterning of a single-sided FCCL substrate according to an embodiment of the present invention includes the steps of forming a single-sided FCCL (10) having a copper foil layer 12 on a polyimide film layer 11 (S1).

In this case, the single-sided FCCL 10 is a raw material used in the manufacture of a flexible circuit board, which is a copper foil laminated film having a single structure by bonding a polyimide film to a copper foil by laminating, .

The ultraviolet transmitting glass 20 is placed on the polyimide film layer 11 of the single-sided FCCL 10 (S2).

At this time, the polyimide film layer 11 of the single-sided FCCL 10 is placed so as to be positioned on the upper side, and the ultraviolet ray transmitting glass 20 is arranged thereon.

Here, the ultraviolet ray transmitting glass 20 is patterned to form a terminal or a circuit on the side of the FCCL 10 through laser irradiation. The laser beam is transmitted through the ultraviolet ray transmitting glass 20, And serves to increase the size by refracting and diffusing the laser beam.

Here, it is preferable that the ultraviolet transmitting glass 20 is placed on the upper surface of the polyimide film layer 11.

Here, the ultraviolet transmitting glass 20 is made of quartz glass or synthetic quartz glass having a refractive index so as to allow the UV laser to be transmitted and to diffuse the laser beam using the refraction of light. And it is preferable to use a material having a thickness of 0.5 to 1.5 mm in order to increase the processing efficiency compared to the use wavelength range of the UV laser (UV laser having a wavelength of 320 to 400 nm).

The ultraviolet transmitting glass 20 is placed on the polyimide film layer 11 of the single-sided FCCL 10 and the ultraviolet transmitting glass 20 is irradiated with a UV laser in the upward direction, 11 is opened by opening the open face of the copper foil layer 12 at the boundary by lamination bonding with the polyimide film layer 11 to form the substrate FCCL 10, Patterning for forming a terminal or a circuit is performed on the side (S3).

At this time, when the UV laser is irradiated to the single-sided FCCL 10 side and patterned for terminal formation or circuit formation, the UV laser beam is transmitted through the ultraviolet transmitting glass 20 as shown in FIG. 2 (a) And the size of the laser beam is adjusted by a dot type laser beam having a larger size. The required portion of the polyimide film layer 11 is removed through the laser beam having the increased size and the polyimide film layer 11 is partially removed to open the copper foil layer 12 to process the patterning.

On the other hand, as shown in FIG. 2 (b), when the ultraviolet transmitting glass 20 is not used, the UV laser is directly irradiated to the single FCCL 10 side without the refraction action of light There is a high risk of damaging the copper foil layer 12, causing a problem of quality deterioration as well as product defects.

Here, it is preferable that the UV laser has a wavelength band of 320 to 400 nm so as to increase ultraviolet ray transmission efficiency and processing efficiency on the ultraviolet ray transmitting glass 20 side.

As shown in FIG. 3 (b), the UV laser generally has a size ranging from 20 to 25 μm regardless of the wavelength band. In the UV laser, As shown in FIG. 3 (a), it can be expanded to a size of 40 to 45 μm.

Here, when the UV-transmitting glass 20 having a thickness of 0.5 to 1.5 mm is applied, the size can be expanded to the maximum useful size by inducing the refraction effect on the laser beam during the processing using the UV laser, If the thickness is more than 1.5 mm, the refractive index is excessively large and the other region is processed outside the machining area, causing defects. When the thickness is less than 0.5 mm, There is a problem in handling such as breakage easily, and cracks may occur in the glass due to the heat of the laser beam during UV laser processing.

In addition, when the thickness of the ultraviolet ray transmitting glass 20 is less than 0.5 mm, the ultraviolet ray transmitting glass 20 is formed to have a size (about 25 to 30 um) .

Accordingly, the present invention having the above-described UV laser processing technique can use the base material of the single-sided FCCL 10 described above and simplify the patterning of both surfaces of the single-sided copper foil layer 12 by double- It is possible to prevent or minimize the damage of the copper foil layer 12 due to the side processing, thereby improving the quality of the product as well as preventing the defect, while shortening the working time and facilitating patterning on both sides .

On the other hand, in the present invention, the double-sided flexible circuit board can be more easily manufactured by using the laser processing method for the double-sided patterning of the single-sided FCCL substrate having the above-described configuration. The circuit board manufacturing method will be described with reference to FIGS. 4 and 5. FIG.

The FCCL 10 having the copper foil layer 12 formed on the polyimide film layer 11 is provided with a substrate (S11).

A necessary portion of the copper foil layer 12 is removed by a photolithography process on the open face of the open copper foil layer 12 of the single-sided FCCL 10 to form a pattern circuit (S12) .

At this time, the patterned circuit can be formed on the open face of the copper foil layer 12 by disposing the photosensitive dry film on the open single-side copper foil layer 12 of the single-sided FCCL 10 and sequentially performing exposure, development and etching .

5, a polyimide film layer 11 is disposed on the upper surface of the resultant structure in which the pattern circuit is formed on the open face of the single-sided copper foil layer 12 through the patterning by the photolithography process And the ultraviolet ray transmitting glass 20 is arranged thereon (S13).

Here, quartz glass or synthetic quartz glass (Fused Silica) is preferably used as the ultraviolet transmitting glass 20, and a thickness of 0.5 to 1.5 mm is preferably used.

Here, it is preferable to use a thickness of 1.0 mm most preferably. However, it is possible to maximize the size of the laser beam during the patterning process using the UV laser, and to increase the efficiency of the processing area target.

Then, a UV laser is irradiated onto the polyimide film layer 11 to process the unprocessed surface of the single-sided FCCL 10, and the ultraviolet transmission glass 20 is irradiated to remove the necessary portion of the polyimide film layer 11 The non-open side of the copper foil layer 12 is opened to perform patterning for forming a terminal or a circuit, thereby proceeding to a double-sided operation (S14).

At this time, it is preferable to use a UV laser having a wavelength band of 320 to 400 nm so as to increase ultraviolet ray transmission efficiency and processing efficiency on the ultraviolet ray transmitting glass 20 side.

Here, when the UV laser is irradiated to the single-sided FCCL 10 side to pattern the terminal or the circuit, the laser beam is refracted and diffused by the ultraviolet transmitting glass 20 to form a dot type laser The required portion of the polyimide film layer 11 is removed by the beam and only the polyimide film layer 11 is partially removed to open the non-open face of the single-sided copper foil layer 12 to the necessary form, Can be processed.

As a result, as shown in FIG. 5, the double-sided flexible circuit board 100 having a pattern on both sides can be fabricated with very simple pattern and double-sidedness with respect to the single-sided copper foil layer 12 of the single-sided FCCL 10 .

That is, according to the present invention, it is possible to manufacture a double-sided flexible circuit board which can improve the product quality while minimizing the defective rate of the product such as the damage of the copper foil layer 12.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Modifications or substitutions may be made.

10: single-sided FCCL 11: polyimide film layer
12: copper foil layer 20: ultraviolet ray-transmitting glass
100: double-sided flexible circuit board

Claims (4)

A laser machining method for two-sided patterning of a single-sided FCCL substrate in which a single-sided FCCL (10) substrate is laser-processed to perform double-sided patterning,
(A) providing a substrate with a cross-sectional FCCL (10) having a copper foil layer (12) formed on a polyimide film layer (11);
(B) disposing an ultraviolet transmitting glass (20) on the polyimide film layer (11) of the cross-sectional FCCL (10);
(C) by irradiating a UV laser so as to penetrate the ultraviolet transmitting glass (20) to burn and remove a necessary part of the polyimide film layer (11) to open the unopened side of the copper foil layer (12) A step of performing patterning for forming a terminal or a circuit on the side of the FCCL 10, , ≪ / RTI &
The ultraviolet ray transmitting glass 20 in the step (B) is quartz glass or synthetic quartz glass (Fused Silica);
In the step (C), the UV laser is irradiated to the single-side FCCL 10 and patterned for forming a terminal or a circuit. The patterned laser beam is refracted and diffused by the ultraviolet transmission glass 20, wherein the copper foil layer (12) is opened and patterned by partially removing only the polyimide film layer (11) with a dot type laser beam.
The method according to claim 1,
In the step (B)
An ultraviolet ray transmitting glass 20 having a thickness of 0.5 to 1.5 mm is used;
In the step (C)
A laser processing method for double-sided patterning of a single-sided FCCL substrate, characterized in that a UV laser having a wavelength of 320 to 400 nm is used.
A method of manufacturing a double-sided flexible circuit board for manufacturing a double-sided flexible circuit board using the single-sided FCCL (10) as a base material,
(A) providing a substrate with a cross-sectional FCCL (10) having a copper foil layer (12) formed on a polyimide film layer (11);
(B) forming a pattern circuit through a photolithography process of disposing a dry film on the opened copper foil layer 12 of the cross-section FCCL 10 and exposing, developing and etching the same;
(C) disposing an ultraviolet ray transmitting glass (20) on the polyimide film layer (11) disposed on the upper surface of the resultant product after the step (B);
(D) A UV laser is irradiated on the polyimide film layer 11 to process a non-processed surface of the single-sided FCCL 10, and the UV-transparent glass 20 is irradiated to burn a necessary portion of the polyimide film layer 11 Thereby forming a terminal or a circuit pattern on the side of the substrate FCCL 10 by performing a patterning process on the side of the substrate FCCL 10 by opening the non-open face of the copper foil layer 12, , ≪ / RTI &
The ultraviolet ray transmitting glass 20 is quartz glass or synthetic quartz glass (Fused silica);
In the step (D), the UV laser is irradiated to the single-side FCCL 10 and patterned for forming a terminal or a circuit, the laser beam is refracted and diffused by the ultraviolet transmitting glass 20, wherein the copper foil layer (12) is opened and patterned by partially removing only the polyimide film layer (11) with a dot type laser beam. Circuit board manufacturing method.
5. The method of claim 4,
In the step (C)
An ultraviolet ray transmitting glass 20 having a thickness of 0.5 to 1.5 mm is used,
In the step (D)
A method for fabricating a double-sided flexible circuit board using a laser processing method for double-sided patterning of a single-sided FCCL substrate, characterized by using a UV laser having a wavelength of 320 to 400 nm.

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