JP3443420B1 - Apparatus and method for manufacturing flexible printed wiring board - Google Patents

Abstract

An object of the present invention is to provide a manufacturing apparatus and a manufacturing method of a flexible printed wiring board which enables formation of a metal or alloy thin film having excellent adhesion strength to a substrate using an ion beam. A resin substrate and a metal substrate are provided by using a rotary sample holder having a cylindrical shape on which a substrate can be placed on a side surface and into which cooling water can be poured. Alternatively, it is possible to control the substrate temperature during the surface treatment process and the vapor deposition process that adversely affect the adhesion strength between the alloys. Also, by using an ion source having a slit-shaped ion irradiation port, very uniform ion irradiation on a large area was enabled. This has made it possible to form a metal thin film having high adhesion strength with a large-area substrate having very uniform characteristics. In addition, by using a small-scale apparatus as shown in FIG. 2 according to the present invention, it has become possible to manufacture a flexible printed wiring board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large area flexible printed wiring board manufacturing apparatus and manufacturing method involving ion beam irradiation.

[0002]

2. Description of the Related Art A flexible printed circuit board has a conductive pattern formed on the surface of a polymer film such as polyester or polyimide, and is flexible, lightweight and inexpensive. Widely used for connecting equipment and electronic parts. As a method of manufacturing such a flexible printed circuit board, after depositing a metal thin film on a polymer film, cutting it into an appropriate size, applying a resist, and exposing using a patterned mask It is manufactured by immersing it in an electrolytic solution and removing the resist pattern by chemical etching. (For example, refer to JP-A-6-21620.)

[0003]

In recent years, personal computers, PCs
Miniaturization of multi-chip modules mounted on cards etc., electronic parts for mobile communication devices such as mobile phones,
Demands for weight reduction, high density, high definition, high reliability, etc. are increasing. Along with this, miniaturization of circuits in a flexible printed circuit board, higher density, and further cost reduction have been required more than ever.

In the conventional technology, one of the performances indispensable for a flexible printed circuit board is that the interface between the metal thin film and the polymer film is eroded by the influence of the electrolytic solution during etching after the metal thin film is formed. It is pointed out that the adhesiveness of them is deteriorated and the above-mentioned miniaturization and high density cannot be dealt with. Further, the conventional method has many steps, and it is difficult to significantly reduce the cost in the future. A method of directly forming a circuit pattern on the surface of a substrate is already known as a method of manufacturing a circuit of a thick substrate made of glass or resin, but the circuit pattern is directly formed on a thin film such as a polymer film. That has never been done. The reason is,
This is because when forming a high-density wiring pattern on a polymer film, the adhesion strength between the pattern and the polymer film could not be maintained due to the miniaturization of the pattern, and it was considered difficult to form a highly accurate circuit. .

Regarding the above-mentioned problems, the adhesion strength between the resin substrate and the metal or alloy is dramatically improved by performing ion irradiation on the substrate before film formation and by forming a circuit at the same time as vapor deposition. This is as reported previously.
(Japanese Patent Application No. 2001-255669) The method and apparatus in the patent application made it possible to mass-produce a flexible printed wiring board having excellent adhesion.

On the other hand, today, the flexible printed wiring board manufacturing apparatus is required to manufacture a large number of small quantities of flexible printed wiring boards at the same time as mass productivity in order to meet the rapidly changing needs. The conventional device is intended for mass production, the device is large-scale and requires a large installation cost. Further, in order to cope with further miniaturization of the wiring pattern, higher adhesion strength between the resin substrate and the metal or alloy is desired.

Further, when an ion source having a circular ion irradiation port is used, it is necessary to scan an ion beam with a magnetic field or the like in order to perform uniform ion irradiation on a resin substrate having a long width. This leads to high cost and complexity of the device.

[0008]

The present invention has been made in view of such conventional problems, and it is possible to form a metal or alloy thin film excellent in adhesion strength with a substrate by using an ion beam. A flexible printed wiring board manufacturing apparatus and method are provided.

According to the present invention, a resin is used by using a rotary sample holder which is of a cylindrical type, on which a substrate can be placed on the side surface, and cooling water can be poured into the inside of the cylinder. It is possible to control the substrate temperature during the surface treatment process and vapor deposition process, which adversely affects the adhesion strength between the substrate and the metal or alloy. In addition, by rotating the sample holder, it became possible to continuously build a metal circuit on a long polymer substrate. Further, by using an ion source having a slit-shaped ion irradiation port, it was possible to perform very uniform ion irradiation to a large area as shown in FIG. This made it possible to form a large-area metal thin film having very uniform characteristics. Further, in the apparatus of the present invention, the polymer substrate on the sample holder is repeatedly rotated to irradiate the surface of the polymer film with oxygen, nitrogen, argon and other ion beams, and a mask having a circuit pattern or a similar mask. The process of covering the surface of the polymer film by the method described above and performing vapor deposition on the surface of the masked polymer film is repeated several times alternately to form a circuit with good adhesion at the same time as film formation. Made possible. Further, by using the small-scale apparatus as shown in FIG. 2 according to the present invention, it becomes possible to manufacture a flexible printed wiring board.

In the present invention, when ions collide with the polymer surface, the impurities adsorbed on the polymer surface are repelled and cleaned, and at the same time, by sputtering,
The surface roughness can be increased. At the same time, new chemical species can be formed by reconfiguring the molecules that make up the polymer and incorporating ions into the polymer, which can significantly improve the adhesion and improve the circuit. It is possible to create a flexible printed circuit board that is compatible with the miniaturization of. Further, by irradiating with the ion beam during or after the vapor deposition of metal atoms, mixing can be caused at the interface between the metal thin film and the polymer substrate, and the adhesion can be greatly improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 shows an embodiment of the present invention. A vacuum chamber 22 is evacuated by an exhaust device 31. In the figure, one exhaust device is provided for each of the upper and lower parts, but this is not the only option. The vacuum container 22 is separated by a shield plate 23 into an ion irradiation chamber 41 and a vapor deposition chamber 42. The shield plate 23 is installed with the intention of maintaining the vacuum degree of the vapor deposition chamber 42 higher than the vacuum degree of the ion irradiation chamber 41, but the shield plate 23 is used for the apparatus of the present invention.
Is not essential. Reference numeral 21 is a cylindrical sample holder on which the polymer substrate 43 is placed. The diameter of the cylinder is 300 mm and the width of the side surface of the cylinder is 400 mm, but the size may be changed according to the size of the vacuum container.
In the present embodiment, the sample holder 21 is made of iron and the polymer substrate 43 can be fixed by a magnet, but the material of the sample holder 21 and the sample fixing method are not limited to this. The ion irradiation device 11 is the sample holder 2 of the ion irradiation chamber 41 in this embodiment.
It was installed to the right of 1. The installation position of the ion irradiation device is not limited to this. By installing the ion irradiation device near the vacuum vapor deposition device 01, it is possible to perform the conventional ion beam assisted vapor deposition method. The number of ion irradiation devices is not limited to this, and a plurality of ion irradiation devices can be used. The ion irradiation port of the ion irradiation device 11 has a slit shape and has a length of 350 mm and a width of 5 mm. The ion irradiation device 11 is installed on the polymer substrate 43 as shown in FIG. A vacuum vapor deposition device 01 is installed inside the vapor deposition chamber 42 below the sample holder 21. The installation position and the number of the vacuum evaporation apparatus are not limited to this. A slit 05 and a mask 05 on which a circuit pattern is printed are installed between the vacuum vapor deposition device 01 and the sample holder 21. The vapor deposition atoms reaching the sample holder 21 are made uniform by this slit 02. This slit is not essential to the invention.

Width 300 mm, length 500 mm, thickness 50
After the μm polymer substrate 43 is placed above the sample holder 21, the exhaust device 31 evacuates the gas. The degree of vacuum in the ion irradiation chamber 41 and the vapor deposition chamber 42 is 1E-05P.
The pressure is reduced from a to about 1E-03Pa. After depressurization, oxygen is supplied to the ion irradiation chamber 41 from the cylinder 13, and the degree of vacuum becomes about 1E-02Pa. The supply amount of this oxygen changes according to the amount of current of the ion beam to be irradiated. Oxygen is converted into plasma in the ion irradiation device 11 and accelerated to several tens eV to several thousands eV. Further, the vapor deposition material is baked in the lower chamber 42, and thereafter vapor deposition is started at a desired film formation rate. Ion irradiation device 11 and vapor deposition device 01
After a stable operation is achieved at, the sample holder 21 starts rotating. While continuing the rotation, ion irradiation and vapor deposition are alternately repeated on the polymer substrate 43 on the sample holder 21 until the desired film thickness is reached. It is also possible to change the vapor deposition material in the course of the above-mentioned ion irradiation and vapor deposition to produce a flexible printed wiring board having a plurality of layers.

[0012]

As described above, the present invention uses a rotary sample holder when forming a thin film on a large-area substrate, and has an ion irradiation port having a racetrack shape, a slit shape, or a similar shape. It is possible to fabricate a flexible printed wiring board having a large area and excellent adhesion strength by performing ion irradiation using an ion source and alternately repeating ion irradiation and vapor deposition.

[Brief description of drawings]

FIG. 1 is a schematic view showing large-area ion irradiation when an ion source having a slit-shaped ion irradiation port according to the present invention is used.

FIG. 2 is a diagram showing an outline of a thin film manufacturing apparatus to which a thin film manufacturing method according to a second invention of the present application is applied.

[Explanation of symbols]

01 evaporation source 02 slit 03 Mask transfer device 04 evaporated atoms 05 mask 11 Ion irradiation device 12 ion beam 13 cylinders 14 stop valve 21 sample holder 22 Vacuum container 23 Shield version 31 exhaust system 41 upper chamber 42 Lower chamber 43 Polymer substrate

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Claims (2)

(57) [Claims] 1. A step of irradiating a surface of a polymer film with oxygen, nitrogen, argon and other ion beams, a step of covering the surface of the polymer film with a mask having a circuit pattern or a method similar thereto, and the mask. A device for manufacturing a flexible printed circuit board, which comprises a step of forming a circuit at the same time as forming a film by performing vapor deposition on the surface of the polymer film, which is a sample holder for mounting a polymer film, In a flexible printed circuit board manufacturing apparatus including a mask device, an ion beam irradiation device, and a vapor deposition device, a substrate can be mounted on a side surface in a cylindrical shape so that cooling water can be poured into the cylinder. Along with the rotating sample holder, there is more than one place for vacuum deposition around the sample holder. A deposition device and one or more ion irradiation devices are provided side by side, and a mask having a circuit pattern formed between the sample holder and the vapor deposition device and a transport device for the mask are installed. Flexible printed wiring board manufacturing equipment. 2. The flexible device according to claim 1, wherein the ion irradiation device has an ion irradiation port having a slit shape or a shape similar to that, and is capable of irradiating a large area of ions. Equipment for manufacturing printed wiring boards.