KR20000063830A

KR20000063830A - Copper circuit wiring formation method of a flexible printed circuit board using a photosensitive film.

Info

Publication number: KR20000063830A
Application number: KR1020000045536A
Authority: KR
Inventors: 이언상
Original assignee: 이언상; 주식회사 세미전자
Priority date: 2000-08-05
Filing date: 2000-08-05
Publication date: 2000-11-06

Abstract

PURPOSE: A method for forming a copper circuit wiring of a flexible printed circuit substrate using a photoresist layer is provided to form a copper circuit wiring on a specific part by using a general plating process. CONSTITUTION: In a method for making a flexible printed circuit board, a photoresist layer(13) is directly deposited on a polyimide base film, a selective light-exposing and a developing photoresist layer are removed by using a parallel beam. Another metal having a copper and a conductive seed metal(14) are selectively formed on a circuit wiring part of the flexible printed circuit substrate. A copper circuit wiring(11) is selectively formed on the conductive seed layer. Chemical and physical etching processes are not performed about the conductive seed layer.

Description

Copper circuit wiring formation method of flexible printed circuit board using photosensitive film. {.}

본 발명은 통신용 휴대단말기 등에 응용되는 연성 인쇄회로기판(Flexible Printed Circuit Board)을 제조하는 공정에 있어서 폴리이미드 베이스필름에 감광막(Photo Resist)을 직접 도포하고 평행광을 조사, 선택적으로 마스킹하여 구리 및 전도성 씨앗층과 같은 금속 혹은 그 합금을 에칭시키는 공정없이 일반적인 도금기술을 이용하여 성장시켜 특정 부분에 구리 회로배선을 형성하는 방법에 관한 것이다.The present invention in the process of manufacturing a flexible printed circuit board (Flexible Printed Circuit Board) applied to a mobile terminal for communication, such as a photoresist directly on a polyimide base film (irradiation) and irradiated with parallel light, selectively masking copper and The present invention relates to a method of forming a copper circuit wiring in a specific portion by growing using a general plating technique without etching a metal or an alloy thereof, such as a conductive seed layer.

일반적으로 종래의 연성 인쇄회로기판의 공정을 살펴볼 것 같으면 도 1에서와 같이 동(銅)판의 습식식각을 통하여 구리 회로배선을 형성하는 제조공정으로서 먼저 동판(11)을 폴리이미드 베이스필름(12)에 증착 혹은 라미네이팅(Laminating)한 후 감광막(13)을 도포하여 산란(散亂)광을 이용 노광, 현상 후 선택적으로 감광막(13)을 제거, 염화제이동 혹은 염화제이철과 같은 에칭액으로 식각한 후 잔여감광막을 제거하여 구리 회로배선(11)을 형성하게 되는 것이다. 그러나 이와 같은 공정에 의해 형성되는 연성 인쇄회로기판의 구리 배선의 경우 습식식각의 등방성으로 인해 두께방향 뿐만 아니라 면방향으로도 식각이 진행되고 또한 구리박막의 불균일한 에칭성으로 인해 25㎛이하의 미세한 구리 회로배선을 형성하기가 어렵다는 것이 문제점으로 지적되고 있으며, 도 2에서 나타낸 바와 같이 전도성 씨앗층(14)을 먼저 형성한 후 감광막(13)으로 마스킹하여 전기도금에 의해 구리 회로배선(11)을 성장시키는 경우도 마지막 공정에서 금속 혹은 그 합금(Alloy)으로 이루어진 전도성 씨앗층(14)을 습식에칭하여 최종 회로배선을 형성해야 하기 때문에 전술한 문제점이 해결되지 않고 있다.In general, if the process of a conventional flexible printed circuit board will be described, as shown in FIG. 1, a copper circuit wiring is formed through wet etching of a copper plate, and the copper plate 11 is first formed of a polyimide base film 12. After the deposition or laminating, the photosensitive film 13 is applied and scattered light is used for exposure and development. After the development, the photosensitive film 13 is selectively removed and etched with an etching solution such as ferric chloride or ferric chloride. After that, the remaining photoresist film is removed to form the copper circuit wiring 11. However, in the case of the copper wiring of the flexible printed circuit board formed by such a process, the etching proceeds not only in the thickness direction but also in the plane direction due to the isotropy of the wet etching, and also due to the non-uniform etching property of the copper thin film, which is less than 25 μm. It is pointed out that it is difficult to form a copper circuit wiring, and as shown in FIG. 2, the conductive seed layer 14 is first formed and then masked with a photosensitive film 13 to form the copper circuit wiring 11 by electroplating. In the case of growing, the above-described problem is not solved because the final seed wiring must be formed by wet etching the conductive seed layer 14 made of a metal or an alloy thereof in the final process.

본 발명은 상기와 같은 연성 인쇄회로기판 제조공정 중 구리와 금속 혹은 그 합금으로 이루어진 전도성 씨앗층의 습식에칭에 있어서 발생되는 문제점을 근본적으로 해소하기 위해 제조공정 자체에 구리 및 여타의 금속에 대한 습식에칭 공정을 제거하고 대신에 감광막을 이용한 도금기술을 이용하여, 구리의 미세패턴을 형성함으로서 향후 연성 인쇄회로기판의 패턴미세화에 대응하고자하는 데 본 발명의 목적이 있는 것이다.The present invention is to wet the copper and other metals in the manufacturing process itself in order to fundamentally solve the problems caused by the wet etching of the conductive seed layer consisting of copper and metal or alloys thereof during the manufacturing process of the flexible printed circuit board as described above. It is an object of the present invention to cope with the pattern miniaturization of a flexible printed circuit board in the future by removing the etching process and forming a fine pattern of copper using a plating technique using a photosensitive film instead.

이와같은 목적을 달성하기 위해 본 발명은, 연성 인쇄회로기판(Flexible Printed Circuit Board)을 제작하는 공정에 있어서 감광막(Photo Resist)을 폴리이미드(Polyimide) 베이스필름에 직접 도포하여 평행광을 이용, 선택적으로 노광, 현상 감광막을 제거하는 단계, 상기 단계에서 형성된 구조에 구리를 포함한 다른 금속 혹은 그 합금으로 형성된 전도성씨앗층(Seed Metal)을 선택적으로 연성 인쇄회로기판의 회로 배선부에 형성시키는 단계 및 형성된 전도성씨앗층에 선택적으로 구리회로배선을 형성시키는 단계로 구성되고 전도성씨앗층을 화학적, 물리적 에칭을 하지 않는 제조공정을 특징으로 한다.In order to achieve the above object, the present invention, in the process of manufacturing a flexible printed circuit board (Flexible Printed Circuit Board) by applying a photosensitive film (Photo Resist) directly to the polyimide (Polyimide) base film using a parallel light, selective Exposing and removing the developed photosensitive film; and optionally forming a conductive seed layer formed of another metal including copper or an alloy thereof in the structure formed in the step, on the circuit wiring portion of the flexible printed circuit board, and And selectively forming a copper circuit wiring on the conductive seed layer, and characterized in that the manufacturing process does not chemically or physically etch the conductive seed layer.

도 1은 일반적인 연성 인쇄회로기판의 제조공정을 나타낸 단면도1 is a cross-sectional view showing a manufacturing process of a typical flexible printed circuit board.

도 2는 전도성 씨앗층을 먼저 형성한 후 감광막을 도포하여 제작되는 연성 인쇄회로기판의 제조공정과정을 나타낸 단면도2 is a cross-sectional view showing a manufacturing process of a flexible printed circuit board manufactured by first forming a conductive seed layer and then applying a photosensitive film.

도 3은 감광막을 먼저 도포하여 제작되는 연성 인쇄회로기판의 제조공정과정을 나타낸 단면도3 is a cross-sectional view illustrating a manufacturing process of a flexible printed circuit board manufactured by first applying a photosensitive film.

<도면의 주요부분에 대한 부호의 설명><Description of the symbols for the main parts of the drawings>

11 : 구리(Copper)배선 12 : 폴리이미드(Polyimide) 베이스필름11 copper wiring 12 polyimide base film

13 : 감광막(Photo Resist) 14 : 전도성 씨앗층(Seed Metal)13: Photo Resist 14: Conductive Seed Layer (Seed Metal)

이하 첨부된 도면에 의해 상세히 설명하면 다음과 같다.Hereinafter, described in detail by the accompanying drawings as follows.

도 2와 도 3은 본 발명에 의해 제작되는 연성 인쇄회로기판의 제조공정과정을 나타낸 수직단면도로서, 도 2의 경우는 폴리이미드 베이스필름(12) 위에 무전해도금 혹은 증착을 통하여 타이타늄텅스텐(TiW) 전도성씨앗층(14)을 먼저 형성하고 감광막(13)을 도포한 후 배선 회로부을 광마스크(Photo Mask)를 통해 평행광을 노광, 현상한 후 2% 수산화나트륨(NaOH)으로 감광막(13)을 선택적으로 제거, 전기도금을 통해 구리배선(11)을 형성하고 잔여감광막을 제거한 후 전도성 씨앗층(14)을 전면에칭을 통해 제거하여 미세한 구리배선(11)을 형성하는 방법을 설명한 것이다. 도 3의 경우는 폴리이미드 베이스필름(12)위에 감광막(13)을 직접 도포하고 배선회로부을 광마스크(Photo Mask)를 통해 평행광을 노광, 현상한 후 2% 수산화나트륨(NaOH)으로 감광막(13)을 선택적으로 제거한 후 무전해도금 혹은 증착을 통하여 전도성 씨앗층(14)을 형성하고 잔여 감광막을 제거한 후 전기도금을 통해 미세한 구리배선(11)을 형성하는 방법을 설명한 것이다.2 and 3 are vertical cross-sectional views illustrating a manufacturing process of a flexible printed circuit board manufactured according to the present invention. In FIG. 2, titanium tungsten (TiW) is deposited on the polyimide base film 12 by electroless plating or deposition. ) First, the conductive seed layer 14 is formed and the photosensitive film 13 is applied, and then the wiring circuit part is exposed and developed in parallel light through a photo mask, and then the photosensitive film 13 is made of 2% sodium hydroxide (NaOH). A method of forming a fine copper wiring 11 by selectively removing and forming a copper wiring 11 through electroplating and removing a residual photoresist layer and then removing the conductive seed layer 14 through front etching is described. 3, the photosensitive film 13 is directly applied onto the polyimide base film 12, and the wiring circuit part is exposed and developed in parallel light through a photo mask, and then the photosensitive film 13 is coated with 2% sodium hydroxide (NaOH). ) To form a conductive seed layer 14 by electroless plating or evaporation after the selective removal of) and to remove the remaining photoresist layer and to form a fine copper wiring 11 by electroplating.

본 발명의 효과는 지금까지 구리 배선의 습식 에칭 공정으로 인해 야기되는 문제점을 완전히 해결할 수 있는 새로운 연성 인쇄회로기판의 제조방법으로서 지금까지 접근하지 못한 수십 혹은 수 마이크론(Micron) 피치의 미세패턴을 형성할 수 있는 발명으로서 향후 통신 휴대단말기 등과 같은 연성 인쇄회로기판이 응용되는 기기의 소형화, 칼라화, 다기능화에 대응하기 위한 연성 인쇄회로기판의 생산에서 일대 전환점을 가져올 수 있을 것이다.The effect of the present invention is a method of manufacturing a new flexible printed circuit board which can completely solve the problems caused by the wet etching process of copper wiring, thus forming a micro pattern of tens or several microns pitch which has not been approached so far. As a possible invention, it will be possible to bring about a turning point in the production of flexible printed circuit boards to cope with the miniaturization, colorization, and multifunctionality of devices to which flexible printed circuit boards such as communication portable terminals are applied.

Claims

(a) In the process of manufacturing a flexible printed circuit board, a photoresist is directly applied to a polyimide base film to selectively remove exposure and development photoresist using parallel light. step

(b) selectively forming a conductive seed layer formed of another metal including copper or an alloy thereof in the structure formed in step (a) in the circuit wiring portion of the flexible printed circuit board;

(c) selectively forming a copper circuit wiring on the conductive seed layer formed in step (b)

(d) a method for selectively forming a circuit wiring of copper comprising the above step and characterized by a manufacturing process which does not chemically or physically etch the conductive seed layer.

In manufacturing flexible printed circuit board, conductive seed layer such as tungsten titanium (TiW) is directly formed by electroless plating or vapor deposition on polyimide base film, coated with photosensitive film, and then selectively converted into parallel light. After exposure and development, a method for selectively forming a circuit wiring of copper, characterized in that the copper wiring is formed through electroplating and the conductive seed layer is removed through the entire surface etching.