KR20120007909A - Manufacturing Method of Printed Board - Google Patents

Abstract

Forming a hole (HOLE) in the surface of the substrate by drilling, and performing chemical copper on the drilled substrate; Electroplating the chemically coated substrate, performing soft etching, a pretreatment process to enhance adhesion to the electroplated substrate, and coating and exposing the dry film to the substrate subjected to the soft etching. Performing the development on the exposed substrate, performing half etching on the developed substrate, peeling dry film on the half-etched substrate, and soft etching on the substrate on which the dry film has been peeled off. Including the step of forming a circuit pattern, by coating the copper plating thickness of the hole uniformly, there is an advantage that the coating of DFR (DRY FILM RESISTER) can be easily formed, so that the fine pattern can be formed in the pattern process after the button formation. The present invention relates to a method for manufacturing a printed circuit board, which can achieve the effect.

Description

Printed wiring board manufacturing method

The present invention relates to a method of manufacturing a printed circuit board to compensate for the occurrence of defects caused by copper plating thickness variation of the button copper plating method.

Printed substrates, such as flexible printed circuit boards, have made remarkable progress in high precision, ultra-thinning, and weight reduction, and high density and miniaturization of circuit patterns formed.

The printed circuit board has a large number of through holes, which are minute through holes, for conducting double-sided circuit patterns and for attaching semiconductor parts.

By the way, in the manufacturing process of a printed circuit board, the panel palting method and the button plating method have conventionally been used regarding manufacture of such a through-hole, and electrical conduction.

<< panel plating method >>

In the panel plating method, with respect to a base material on which copper foil is attached to both surfaces (surface and back surface) of an insulating material,

First, after drilling a large number of through holes for through-holes, an electrically conductive process was conducted in the through holes, and then the substrate was entirely copper electroplated. Then, by the panel plating method, the substrate in which the through hole is conducted with copper plating is sequentially subjected to patterning steps of known exposure, development, etching, and stripping. As a result, a circuit pattern was formed, whereby a printed circuit board was produced.

However, in such a panel plating method, copper foils on both sides as well as through holes are copper plated as a whole. Thus, the printed circuit boards are also plated with copper circuit patterns on both sides. Difficulties of increasing also were pointed out. This point was regarded as a remarkable problem for the flexible printed circuit board.

<< new, old button plating method >>

Therefore, as a method for overcoming such a difficulty, a button plating method has been developed, and it is currently becoming a mainstream in the field where flexibility and flexibility, and furthermore, light weight are particularly important.

In this button plating method, a plurality of through holes for through holes are first drilled on the substrate, and then conductively processed in the through holes, the substrate is covered with a photosensitive dry film, and a negative mask is placed on the outside thereof. A photo mask is applied, thereby exposing and developing the photosensitive dry film as a plating resist, and then the inside of the opened through hole and the periphery of the through hole are approximately button ( button) is electroplated with copper. By the button plating method, a substrate having copper plated through holes and the like was formed through a patterning step, thereby forming a circuit pattern, thereby producing a printed board.

However, with respect to this conventional button plating method (hereinafter referred to simply as the old button plating method), the position of each through hole of the base material and the position (and specific electroplating position) of each corresponding location of the photomask are shifted. There were a lot of points.

That is, in the conventional button plating method, the position is often misaligned due to the expansion and contraction of the substrate and the photo mask and the difficulty of aligning the positions with the naked eye, and this position shift is often caused by disconnection. defects).

1 is a process chart of a conventional method for manufacturing a printed board.

Referring to FIG. 1, first, a plurality of through holes for through holes are drilled, and then soft etching is performed to increase the adhesion of the dry film.

Then, after electroless copper plating, the dry film is coated, and a film on which the circuit is drawn is placed on the coating, followed by exposure and development.

Next, after performing lactic acid copper plating, a peeling step of removing the coating layer coated on the metal surface is performed to soft etch to complete the manufacture of the circuit board.

The present invention is proposed to solve the above problems,

An object of the present invention is to uniformize the thickness of the copper plating of the hole and to facilitate the coating of DFR (DRY FILM RESISTER) for pattern formation afterwards to form a fine pattern in the pattern process after button formation,

FCCL, a raw material of double-sided FPCB, can be rolled or sheeted to produce superior quality PCBs with excellent effects in terms of bending characteristics and reliability. It is an object of the present invention to provide a method for manufacturing a printed circuit board.

The present invention includes the following embodiments in order to achieve the above object.

According to one embodiment of the invention, the step of forming a hole (HOLE) on the surface of the substrate by drilling,

Performing chemical copper on the drilled substrate;

Performing electroplating on the substrate coated with chemical copper;

Performing soft etching, a pretreatment process for enhancing adhesion to the electroplated substrate,

Coating and exposing the dry film to the substrate subjected to soft etching,

Developing on the exposed substrate,

Half etching the developed substrate,

Peeling a dry film on the half-etched substrate,

And performing a soft etching on the substrate from which the dry film is peeled off, thereby forming a circuit pattern.

According to another embodiment of the present invention, the substrate is characterized by using a flexible flexible printed substrate.

According to another embodiment of the present invention, the substrate processed up to the electroplating process is subjected to SOFT etching, which is a pretreatment process to enhance the adhesion of the dry film to be attached, and is formed on the outer surface of the substrate rather than the hole by HALF etching It is characterized in that the copper plating can be removed.

According to another embodiment of the present invention, in the exposing step of the dry film, the through-holes are exposed and cured so that a portion other than the holes is developed in the developing process, so that the copper is exposed.

According to another embodiment of the present invention, the half-etching step removes the exposed copper foil, not the pattern of the circuit, to a thickness in which the plating is formed to form a thin layer so that the thickness of the copper can be smoothed as the pattern is finened to smooth the pattern reproduction. It can be characterized by.

The present invention can achieve the following effects by the above configuration.

In the method of manufacturing a printed circuit board according to the present invention, the stability of the hole and the coating of DFR (DRY FILM RESISTER) can be easily coated, which has the effect of forming a fine pattern in the pattern process after button formation.

The small thickness variation of copper plating and no significant difference in plating thickness for each model make it easy to set the conditions for early development products.

In addition, by performing HALF etching and soft etching, it is possible not only to reduce the thickness of the substrate, but also to easily form a fine circuit. Since the interlayer electrical reliability is high, there is an effect suitable for the manufacture of double-sided or multilayer printed circuit boards.

1 is a process chart for a manufacturing method of a conventional printed board
2 is a flow chart of a method of manufacturing a printed board according to an embodiment of the present invention.
Figure 3 is a process diagram of a manufacturing method of a printed circuit board according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, if it is determined that the detailed description of the related well-known configuration or function may obscure the subject matter, the detailed description thereof will be omitted.

2 is a flowchart of a method of manufacturing a printed board according to an embodiment of the present invention, and FIG. 3 is a process diagram of a method of manufacturing a printed board according to an embodiment of the present invention.

Referring to FIG. 2, the method of manufacturing a printed circuit board according to the present invention first forms a hole (HOLE) on the surface of a flexible printed circuit board (F.P.C.B) by drilling (S10). After performing soft etching (S20) on the drilled substrate, chemical copper is performed (320).

After forming the copper copper is subjected to electroplating (S40). Next, SOFT etching is performed, which is a pretreatment process to enhance adhesion (S50). And the coating and exposure of the dry film exemplified in the background art (S60). Development is performed on the exposed substrate (S70).

Next, HALF etching is performed (S80).

After the HALF etching, the circuit pattern is formed by performing SOFT etching once again through the process of peeling the dry film (S90) (S100).

First, the printed board E is largely divided into a flexible flexible printed board (FPC) and a rigid rigid printed board, but in the present invention, a flexible printed board (FPC) is used, and the flexible printed board (FPC) is It becomes a laminated board which affixed copper on both surfaces by which copper foil was affixed on both surfaces of an insulating material (also called an insulating film in the case of a flexible substrate). Insulating material, which is a base material, has a polyimide resin film, an aramid resin film, a liquid crystal polymer film, and other flexibility and insulation for flexible printed circuit boards. It becomes a resin film. As the copper foil, a rolled foil, an electrolytic foil, a special electrolytic foil, a plating foil, or the like is used.

As such an insulating material, there are a double layer type and a single layer type. In the multilayer type, copper foil is laminated on both surfaces of an insulating material via an adhesive agent, respectively. As the adhesive, an epoxy resin, a halogen free epoxy resin, a high Tg-epoxy resin, or the like is used. In contrast, in the single layer type, the copper foils F are directly laminated on both surfaces of the insulating material. The single layer type insulating material is produced by a casting method, a laminator method, a metalliding method, a sputtering method, or the like.

Looking at the manufacturing method using the flexible printed circuit board (FPC), as shown in Figure 3, a plurality of through holes for the through-hole (1) in the substrate is drilled.

Through-holes 1 are minute pores that penetrate between both surfaces (the front and rear surfaces) (one side and the other side) of the printed circuit board E, and are formed in one printed circuit board E in a large number. And the through hole 1 is used for the conduction connection between the circuit patterns A of both surfaces, or (and) for the attachment of the semiconductor component etc. mounted in the circuit pattern A. As shown in FIG. As for the hole diameter of the through-hole 1, the thing of 0.2 mm or more and 0.5 mm or less increases, and the thing of about 0.1 mm by the drill method and the thing of about 0.05 mm by the laser method are appearing, too.

The electrochemical copper process is performed to the board | substrate E with which the through-hole 1 was processed, and the electroconductive film 2 is formed. The chemical copper treatment refers to an electroless copper plating process, also referred to as chemical or catalytic plating. Conductivity is applied to the inner wall of the through hole to impart conductivity, and the thickness of copper to be plated is 0.3 to 1.0 μm, and Pd is mainly used as a catalyst.

Electrochemical copper plating is again performed on the chemically copper-treated substrate to form copper plating 3 on the conductive film 2. Electroplating is a process of secondary plating the copper of the thickness specified in the pattern and the inner wall of the hole by using the electroprecipitation method. The amount of precipitation is determined by the current density and the precipitation time.

The substrate processed until the electrocopper plating process is subjected to SOFT etching, which is a pretreatment process for enhancing the adhesion of the dry film to be attached later, to remove the copper plating 3 formed on the outer surface of the substrate E.

Next, in the manufacturing method, the dry film 4 is pressed onto the front surface-treated substrate E by applying predetermined heat and pressure, and then the working film is matched on the dry film 4 to provide light energy during the exposure time. It can be supplied to reproduce the required pattern image. On the other hand, in the present invention, it is preferable to proceed with the exposure process in a state in which the through hole (1).

Then, the substrate E coated with the dry film 4 or the like is developed. The developer is penetrated through the through hole 1 of the substrate E so that the dry film 4 can be dissolved and removed by the developer. do.

The developed substrate (E) goes through the HALF etching step, where HALF etching is a process that does not exist in the past, and is used for the purpose of smoothing the pattern reproduction by thinning the copper thickness as the pattern is finened. In the process of uniformly etching OZ or 1/4 OZ copper foil to a desired thickness or in the present invention, the exposed copper foil surface, not the hole, is removed to the thickness where the plating is formed to form a thin layer.

Then, after peeling and removing the dry film 4, soft etching may be performed to make the thickness of the printed circuit board thinner, and to easily form a microcircuit on the surface of the dynamic layer board.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

E: Substrate 1: Through Hole
2: conductive film 3: copper plating
4: dry film

Claims (5)

Drilling to form a hole (HOLE) in the surface of the substrate,
Performing soft etching on the drilled substrate,
Performing chemical copper on the substrate subjected to soft etching;
Electroplating the chemically coated substrate,
Performing soft etching, a pretreatment process for enhancing adhesion to the electroplated substrate,
Coating and exposing the dry film to the substrate subjected to soft etching,
Developing on the exposed substrate,
Half etching the developed substrate,
Peeling the dry film onto the half-etched substrate,
Method of manufacturing a printed circuit board comprising the step of performing a soft etching on the substrate from which the dry film is peeled off to form a circuit pattern The method of claim 1,
The substrate is a manufacturing method of a printed circuit board, characterized in that using a flexible flexible printed circuit board The method of claim 1,
The substrate processed to the electroplating process is subjected to SOFT etching, which is a pretreatment process to enhance the adhesion of the dry film to be attached, and by HALF etching to remove the copper plating formed on the outer surface of the substrate, not the hole Manufacturing method of printed circuit board The method of claim 1,
In the exposure step of the dry film, the through-holes are exposed and cured so that the non-holes are developed in the developing step, and the exposure process is performed so that the copper is exposed. The method of claim 1,
The half-etching step is to remove the exposed copper foil, not the pattern of the circuit, to a thickness formed by plating to form a thin, thereby reducing the thickness of the copper as the pattern is finened to facilitate the pattern reproduction of the printed circuit board Manufacturing method

Images