KR20160126192A

KR20160126192A - Method of manufacturing transparent printed circuit board

Info

Publication number: KR20160126192A
Application number: KR1020150056944A
Authority: KR
Inventors: 김명종; 양원모; 배호은
Original assignee: 대덕지디에스 주식회사
Priority date: 2015-04-23
Filing date: 2015-04-23
Publication date: 2016-11-02

Abstract

The present invention performs an oxidation treatment, such as brown oxide, black oxide or the like, onto a surface of a copper foil circuit in the shape of a net in order to improve a haze characteristic and a transmittance characteristic that an existing transparent flexible circuit board has, or performs a plasma treatment or a corona treatment to increase visibility. A method for manufacturing a transparent printed circuit board includes the steps of: (a) preparing a substrate having a transparent base film covered with a conductor film; (b) forming a mask in which a circuit pattern in the form of a net is transferred; (c) transferring the circuit pattern in the form of a net onto the conductor film; (d) assigning illumination to the surface of the conductor film; and (e) stacking and laminating a transparent cover lay.

Description

[0001] METHOD OF MANUFACTURING TRANSPARENT PRINTED CIRCUIT BOARD [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology of manufacturing a transparent printed circuit board (PCB), and more particularly, to a technique of manufacturing a transparent flexible printed circuit board having improved visibility.

2. Description of the Related Art As electronic products such as a flexible printed circuit (FPC) and a head mount display (HMD) for a head-up display (HUD) have been formed in recent years, This attracts attention.

As a conventional technique for manufacturing a transparent printed circuit board, there is a patent application No. 10-2014-0062007 filed with the Korean Intellectual Property Office on Apr. 25, 2013 by the applicant of the present invention. The prior art of the applicant of the present invention employs a technique of embodying a mesh net copper circuit on a transparent base film having excellent light transmittance in place of the conventional strip circuit type copper circuit.

That is, the prior art of the applicant of the present application realizes transparency of a circuit by constituting a copper foil circuit in the form of a polygonal mesh. The copper wire is formed of a fine line and a net structure, and even if opaque metal is used, a sufficient empty space is placed between the fine line and the fine line. Therefore, .

However, in order to secure the high visibility (≧ 85%) required by the above-mentioned HMD or HUD electronic products, an innovative technique capable of further improving the visibility in addition to the network-shaped copper-clad circuit technology is needed.

1. Korean Patent Publication No. 10-2005-0024072. 2. Korean Patent Publication No. 10-2008-0000017.

It is an object of the present invention to provide a technique of manufacturing a transparent printed circuit board which improves the visibility of a transparent printed circuit board.

The present invention is characterized by improving the visibility by oxidizing the surface of the copper foil with Brown Oxide or Black Oxide in order to improve the haze characteristic and the light transmittance characteristic of the conventional transparent flexible circuit board.

The present invention may improve the visibility of the circuit by forming a physical roughness on the surface of the copper foil such as a plasma treatment or a corona treatment.

INDUSTRIAL APPLICABILITY The present invention improves visibility by reducing irregular reflection on a copper-clad circuit of a flexible circuit board. When the method according to the present invention is applied, the light transmittance can be increased by 1% or more, and the space between the copper foil meshes can be significantly reduced by increasing the light transmittance by 1% or more, thereby realizing a fine pitch transparent circuit board .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A to Fig. 1H show a process sequence for manufacturing a transparent printed circuit board according to a preferred embodiment of the present invention.
2A and 2B are respectively a circuit diagram of a network structure according to the prior art and a circuit diagram of a mesh structure processed according to the present invention.

The present invention relates to a method of manufacturing a transparent printed circuit board, comprising the steps of: (a) preparing a substrate coated with a conductor film on a transparent base film; (b) forming a mask on which a circuit pattern of a net shape is transferred by bringing a dry film into close contact with the conductor film and conducting a series of image processes such as photographing, exposure, development, etching, and the like; (c) selectively etching the conductor film using the mask as an etching mask to transfer a net-shaped circuit pattern to the conductor film; (d) subjecting the conductor film to a brown oxide film or a black oxide film with an oxide chemical, or applying a roughness to the conductor film surface through a plasma treatment or a corona treatment; And (e) a step of laminating the transparent coverlay by heating and pressurizing the transparent coverlay.

Hereinafter, a method of manufacturing a transparent printed circuit board according to the present invention will be described in detail with reference to FIGS. 1 and 2.

FIGS. 1A to 1H are views showing a process sequence for manufacturing a transparent printed circuit board according to the present invention.

Referring to FIG. 1A, the present invention can be used as a starting material for a transparent flexible clad laminate (FCCL) 10. The transparent FCCL according to the present invention has a structure in which the conductive film 10a is coated on the transparent base film 10b and the conductive film 10a is made of iron (Fe), gold (Au), silver (Ag) , Nickel (Ni), platinum (Pt), molybdenum (Mo), or a combination thereof.

The transparent CCL according to the present invention can be applied to a film having a light transmittance of 80% or more, such as PET (polyethylene terephthalate), PEN (polyethyle naphthalate), PES (poly methyl sulfone), PAI poly methyl methacrylate, TAC (triacetyl cellulose), PC (poly carbonate), PAC (poly acrylic), COC (cyclic olefin copolymer), polystyrene, transparent polyimide, nylon, polytetrafluoroethylene (polyether ether ketone), and the like. The thickness is preferably 200 占 퐉 or less.

Referring to FIG. 1B, a dry film (D / F) 20 is closely attached to a transparent FCCL 10 according to the present invention. 1C, a circuit pattern is transferred onto the dry film 20 by covering the mask and performing exposure and development.

Referring to FIG. 1D, a circuit is formed by etching the conductor film 10a using the dry film 20 to which a pattern has been transferred, as an etching mask. Referring to FIG. 1E, the dry film 20 is peeled off.

In order to ensure the transparency of the circuit board, the present invention is characterized by implementing a circuit with a plurality of fine lines and a plurality of meshes formed by the fine lines when a circuit of a net type is formed. That is, the present invention realizes transparency by constructing a circuit in the form of a polygonal mesh.

That is, the conductive line has a mesh structure by a fine line and a mesh, and even if an opaque metal is used, a sufficient empty space is placed between the fine line and the fine line. Therefore, will be.

As a preferred embodiment of the present invention, transparency can be realized by increasing the light transmittance by making the width W of the fine lines thin to 1 to 100 mu m and widening the interval L between the lines to 100 to 1000 mu m. The thickness T of the copper foil for realizing the mesh-type copper-clad circuit according to the present invention may be in the range of 1 to 72 탆. As a preferred embodiment of the present invention, it is preferable that the effective width of a circuit composed of repeated lines and meshes is 0.1 to 3 mm in total of the width W of the line and L of the mesh.

Referring to FIG. 1F, the surface of the conductor film 10a is subjected to Brown Oxide or Black Oxide processing to oxidize the surface of the conductor film. 1F schematically shows a state in which an oxide film 30 is formed on the surface of the conductor film.

Brown oxide or black oxide can oxidize metal surfaces using oxide chemical. That is, the brown oxide film or the black oxide film can be formed through a chemical conversion or anodic oxidation coating process, and the copper foil can be formed of copper oxide (CuO) in an electrolyte solution tank containing a high concentration of an alkali salt and an oxidizing agent.

As a preferred embodiment of the present invention, the copper foil is treated by maintaining 45 to 55% v / v of Techni Pro-Bond Oxide Solution A of Technic Inc. or 35 to 45% v / v of Solution B at 55 to 65 ° C, A brown oxide film or a black oxide film can be formed. The technique of treating brown oxide or black oxide is described in Korean Patent Publication No. 10-2011-0023925.

As another embodiment of the present invention, the visibility of the circuit may be improved by physically forming a roughness on the surface of the copper foil, such as a plasma treatment or a corona treatment.

Referring to FIG. 1G, a transparent cover layer (C / L) 40 is formed on a substrate treated with a brown oxide or a black oxide.

The transparent coverlay is a material in which a transparent film is coated with a transparent film. The transparent film can be made of the same material as the transparent base film 10b described above, and has good light transmittance (? 80% ), An acrylic resin, an urethane-based resin, a PET-based resin, a PAI-based resin, a polystyrene-based resin, a cyanoacrylate-based resin, or the like can be impregnated and used .

Referring to FIG. 1H, the cover rails 40 in the contact state are laminated by heating the transparent coverlay 40. Subsequently, substrate processing is completed through ENIG plating or OSP treatment, and finish processing such as electroless Tin e plating and external processing.

2A and 2B are photographs showing a circuit of a network structure according to the prior art and a circuit of a network structure subjected to an oxide film process according to the present invention.

Comparing FIGS. 2A and 2B, it can be experimentally confirmed that the light transmittance increases by about 1% point from 85.64% to 86.06% when the brown oxide film treatment is performed. In addition, haze improved by 0.2 percentage points from 3.01% to 2.79%.

The above visibility improvement effect may be mistaken for a small number of points because it indicates a numerical value of 1% point. However, the visual improvement effect of 1% actually reduces the pitch interval of the network structure by several tens of times Give it to me. As a result, it is possible to realize a circuit pattern of a micro pattern.

The foregoing has somewhat improved the features and technical advantages of the present invention in order to better understand the claims of the invention described below. Additional features and advantages that constitute the claims of the present invention will be described in detail below. It is to be appreciated by those skilled in the art that the disclosed concepts and specific embodiments of the invention can be used immediately as a basis for designing or modifying other structures to accomplish the invention and similar purposes.

In addition, the inventive concepts and embodiments disclosed herein may be used by those skilled in the art as a basis for modifying or designing other structures to accomplish the same purpose of the present invention. It will be apparent to those skilled in the art that various modifications, substitutions and alterations can be made hereto without departing from the spirit or scope of the invention as defined in the appended claims.

10a: base film
10b: conductor film
20: Dry film
30: oxide film
40: Cover Ray

Claims

A method of manufacturing a transparent printed circuit board,
(a) preparing a substrate on which a conductor film is coated with a transparent base film;
(b) forming a mask on which a circuit pattern of a net shape is transferred by bringing a dry film into close contact with the conductor film and performing a series of image processes such as photographing, exposure, development, etching, and the like;
(c) selectively etching the conductor film using the mask as an etching mask to transfer a net-shaped circuit pattern to the conductor film;
(d) subjecting the conductor film to a brown oxide film or a black oxide film with an oxide chemical, or applying a roughness to the conductor film surface through a plasma treatment or a corona treatment; And
(e) a step of laminating a transparent coverlay by heating and pressing
Wherein the transparent printed circuit board comprises a transparent printed circuit board.