JPH02184095A - Wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE:To efficiently and inexpensively form a wiring board by making a resin material for forming an insulator conductive by application of an ion beam of a conductor pattern to the surface of the insulator in the wiring board. CONSTITUTION:One surface of an insulator 1 made of a resin film is irradiated with an ion beam to make a resin material for forming a resin film conductive, thereby forming conductor patterns 2,... the resin material for forming the insulator 1 desirably includes, for example, heat resistant resin material such as polyimide having aromatic ring or heterocyclic ring. Since the heat resistant resin material can sufficiently endure against approx. 150-300 deg.C generated at the time of application of the ion beam, the conductor patterns having sufficient conductivity can be formed in a short time by increasing the current value of the applied ion beam to further efficiently form the wiring board. The heat resistant resin material includes, for example, polyimide, polyarylate, PEEK, polyetherimide, polyethyrsulfone, melamine resin, phenol resin, etc.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a wiring board such as a flexible wiring board and a method for manufacturing the same, and more specifically, to a wiring board having a novel configuration and an efficient method thereof. This relates to a manufacturing method.

<Conventional technology> Conventionally, wiring boards (B) such as flexible wiring boards
Figure (As shown in the figure, an insulating substrate made of resin material (5)
and a conductor pattern (6) made of conductive material such as copper...
It has a laminated structure.

Further, the conventional wiring board (B) is, for example, as shown in FIG.
As shown in , after a conductive thin film (6') such as copper foil is laminated on the surface of an insulating substrate (5) via an adhesive layer (7), the surface of the conductive thin film (6') is An etching resist layer (8) having a predetermined circuit pattern is laminated and formed, and a portion of the conductive thin film that is not masked by the etching resist layer (8) is etched away, and then the etching resist layer (8) is etched onto the insulating substrate (5). A substrative method is used to form the conductor pattern (6) required for the circuit design.A conductive material is deposited and fixed by plating etc. only on the circuit pattern part based on the circuit design on the surface of the insulating substrate (5) to form the conductor pattern. It is manufactured by a manufacturing method such as an additive method for forming (6), or a semi-additive method that combines the above-mentioned substrative method and additive method.

<Problems to be Solved by the Invention> However, most conventional wiring boards are made by laminating and integrating an insulating substrate made of different materials and a conductor pattern, such as the combination of resin material and copper mentioned above. Therefore, due to differences in expansion and contraction coefficients between the two, warpage, delamination, etc. may occur during manufacturing or use.

Furthermore, as shown in Fig. 4 (Tada), conventional wiring boards have an uneven shape in which conductor patterns (6) are laminated on the surface of an insulating substrate (5). (
6) In wiring boards that are used with exposed parts, fine dust and dirt tend to accumulate in the uneven parts, and these dust and dirt can cause dielectric breakdown of the conductor patterns, causing malfunctions. There is a possibility that this will happen.

In addition, since the conductor patterns on conventional wiring boards mainly use metal materials with high specific gravity,
Currently, it is impossible to expect further weight reduction in flexible type wiring boards in which the insulating substrate is thin and the weight of the conductive circuit is large in the total weight.

Furthermore, as shown in FIG. 4(b), in the case where the insulating substrate (5) and the conductive thin film (6') are bonded via the adhesive layer (7), the adhesive used is Most of them have insufficient heat resistance, so even if insulated substrates made of highly heat-resistant resin materials are used in applications that require heat resistance,
The heat resistance of this highly heat-resistant resin material cannot be fully utilized.

On the other hand, all of the conventional wiring board manufacturing methods described above have a large number of steps and include a wet process such as the etching process in the substrative method and the plating process in the additive method. There is a problem in that wiring boards cannot be manufactured efficiently and at low cost, such as requiring additional equipment.

The present invention has been made in view of the above circumstances, and
It is an object of the present invention to provide a wiring board having a conductor pattern of a new configuration that can solve various problems that conventional wiring boards have, and a manufacturing method that can efficiently and inexpensively manufacture the wiring board.

Means and operation for solving the above problems> A wiring board according to the invention according to claim 1 (hereinafter referred to as the "wiring board of the present invention") for solving the above problems has at least a surface of an insulator made of a resin material. The method for manufacturing a wiring board according to the invention according to claim 2 (hereinafter referred to as "the manufacturing method of the present invention") is characterized in that a conductor pattern formed by irradiation with an ion beam is provided on the wiring board. A circuit pattern mask that allows an ion beam to pass through only the portion corresponding to the circuit pattern is placed on the surface of an insulator made of A feature is that a conductor pattern corresponding to a circuit pattern is formed on the surface.

In the wiring board of the present invention, the conductor pattern is formed by irradiating the surface of the insulator with an ion beam to make the resin material constituting the insulator conductive, so that the insulator and the conductor pattern are of the same type. The material is formed as a continuous phase. The reason why the resin material is made into a conductor by ion beam irradiation is presumed to be because the resin material is carbonized or the resin material is partially oxidized or reduced by implantation of irradiation ions (for example, T
, Venkatesan, et al., J.Ap.
pl, Phys, 54.3150゜June 1983
reference).

Furthermore, in the manufacturing method of the present invention, the surface of the insulator is irradiated with the ion beam using a circuit pattern mask that allows the ion beam to pass through only the portion corresponding to the predetermined circuit pattern. Formation of conductive patterns becomes easier.

<Examples> Hereinafter, the present invention will be described in detail based on the accompanying drawings showing examples.

First, regarding the wiring board of the present invention, FIG. 1 (
This will be explained with reference to rice fields.

The wiring board (A) of this example is a flexible type wiring board in which the insulator (1) is made of a flexible resin film, and one surface of the insulator (1) made of the resin film is
A conductor pattern (2
)... is provided.

As the resin feed constituting the insulator (1), a heat-resistant resin material such as polyimide, which has an aromatic ring or a multi-ring in its molecule, is preferably used. The above heat-resistant resin material is
Since it can sufficiently withstand temperatures of approximately 150 to 300°C that occur during ion beam irradiation, it is possible to increase the current value of the irradiated ion beam and form a conductive pattern with sufficient conductivity in a short time. It is possible to manufacture wiring boards even more efficiently. Examples of such heat-resistant resin materials include polyimide, polyarylate, polyetheretherketone (PEEK), polyetherimide, polyethersulfone, melamine resin, and phenol resin.

In the wiring board (A) of the above embodiment, by irradiating one side of the insulator (1) with an ion beam and converting the resin material in the irradiated part into a conductor, the conductor pattern (2)... is made of an insulator. Since it is made of the same type of material as (1) and is formed as a continuous phase with insulator (1), there is no risk of interlayer separation or warpage occurring between the two. In addition, the surface of the wiring board (A) having the conductor pattern (2) is smooth and has no unevenness where dust and dirt can accumulate, so insulation breakdown etc. caused by these dust and dirt may occur. There is no risk.

Moreover, since no metal material is used, it is possible to make the product even lighter than before, and since no adhesive is used, it is possible to make it even more heat resistant than before.

Note that the wiring board of the present invention is not limited to the configuration of the above embodiment, and various design changes can be made without changing the gist of the present invention.

For example, although the wiring board (A) in the above embodiment was a flexible type, it may also be a rigid type, and in that case, a plate-shaped insulator that is not flexible should be used. Good.

Further, in the above embodiment, the conductor pattern (2)...
The conductor patterns (2)... were formed only on one surface of the insulator (1), but as in the modified wiring board (A') shown in Fig. 1), the conductor patterns (2)... It may be formed on both surfaces of 1).

The insulator (1) may be made of only a resin material like the resin film in the above embodiments, or may be a resin material filled with synthetic fibers, glass fibers, etc.
A composite plate made of a resin material and a base material such as paper, glass cloth, glass mat, glass vapor, or synthetic fiber cloth can also be used. It is also possible to use an insulator for multilayer wiring boards on which inner layer circuits have already been formed.

In addition, if the degree of ion beam irradiation is adjusted for a part of the conductor pattern (2) to give it an appropriate resistance value, that part of the conductor pattern can be used as a resistance element. Become what you can.

The manufacturing method of the present invention relates to a method of efficiently manufacturing the wiring board of the present invention. Below, regarding the manufacturing method of the present invention,
An embodiment will be described with reference to FIGS.

First, an insulator (1) made of the aforementioned resin film or the like is prepared (FIG. 2(a)).

Next, a circuit pattern mask (3) made of metal foil in which through holes (31) corresponding to the circuit pattern have been formed by etching or the like is superimposed on one side of the insulator (1) (second (in the figure)).

The thickness of the metal foil constituting the circuit pattern mask G) is greater than the maximum reach depth of the irradiation ion beam, so that only the through-hole portions can transmit the ion beam.

Next, as shown by the arrow in FIG. 2(C), the insulator (1)
An ion beam is irradiated onto the surface of the side on which the circuit pattern mask (3) is superimposed. Then, the insulator (1
), only the portion facing the through hole (31) is irradiated with the ion beam, the resin material in the irradiated portion becomes conductive, and a conductor pattern corresponding to the circuit pattern is formed.

Note that the irradiation ion beam has a large mass of ion species,
The larger the amount of implanted ions and the greater the energy of the irradiated ions, the easier it is to make the resin material a conductor.

In other words, as the ionic species, elements with a larger mass than the metal are preferably used, and among them, metal elements, etc.
Elements that are solid at normal pressure are more preferably used. If the ionic species is a hydrogen atom with a smaller mass than the southern one, there is a possibility that the resin material may not be sufficiently conductive to be used as a conductive pattern, although it depends on the type of resin material. In addition, the above metal elements remain in the irradiated insulator (1) for a long time compared to elements that are gases at room temperature, such as rare gases, halogens, and nitrogen, so the amount of implanted ions is relatively small. in,
Resin materials can be efficiently made into conductors.

It is preferable that the amount of implanted ions is 1×101'cm-2 or more, and the energy of irradiated ions is 0.2 MeV or more.If either the amount of implanted ions or the energy of irradiated ions is less than the above values, the resin material Although it depends on the type, there is a possibility that the resin material cannot be made into a sufficient conductor. In addition, to set the energy of irradiated ions to 1 eV,
Since an acceleration voltage of 1 V is required in a vacuum, in order to increase the energy of irradiated ions to 0.2 MeV or more, the acceleration voltage of the ion beam should be set to 0.2 MV or more.

In addition, the above implanted ion amount is 5 x 10180-
The energy of the irradiated ions is preferably 50 MeV or less. If the amount of implanted ions and the energy of irradiated ions exceed the above values, there is a risk that the surface of the resin material will deteriorate excessively and the physical properties of the surface will deteriorate.

A normal ion implantation device can be used as the ion beam irradiation device.

After ion beam irradiation, if the circuit pattern mask (3) is removed, a wiring board (with conductor patterns (2) formed on the surface of the insulator (1), as shown in FIG.
A) is completed. Note that the wiring board (A'
), the above steps may be performed on both the front and back surfaces of the insulator (1).

According to the manufacturing method of the above embodiment, the insulator (1
) By irradiating the surface of the insulator (1) with an ion beam, a conductor pattern (2) corresponding to the circuit pattern can be formed on the surface of the insulator (1). and ion beam irradiation.
The number of steps is reduced to 111 compared to conventional wiring board manufacturing methods, and as a result, production efficiency is improved. In addition, in this method, wet type 1 such as etching and plating is used.
Since the process does not require a lot of time, there is no need for equipment for environmental protection.

Note that in order to form the above-described resistive element in a part of the conductive pattern, only the resistive element part is irradiated with a weak ion beam, or the ion beam irradiation time is made shorter than other parts. The degree of conductivity of the resin material may be adjusted.

In the above embodiment, a metal foil having through holes was used as the circuit pattern mask (3), but after coating and forming a photosensitive layer made of a photosensitive resin material on the surface of the insulator (1),
It is also possible to use a so-called photoresist layer in which through holes are formed by exposure and development according to a circuit pattern.

In addition, as another circuit pattern mask, use one in which the part corresponding to the circuit pattern is made of a material that easily transmits the ion beam, and the other part is made of a material that does not transmit (for example, reflects) the ion beam. You can also.

Specific example 1> On the surface of a polyimide film with a thickness of 50 μm,
Thickness 0.1m with a through hole of m x width 0.5mm
After superimposing N m stainless steel circuit pattern masks, use the ion beam irradiation device shown in Figure 3 to
2+ ion beam, current value 1.0 μACI11-2
Irradiation was carried out for about 45 hours under these conditions to produce a wiring board on which a conductor pattern corresponding to the shape of the through hole was formed. Note that the energy of the irradiated ions was IM e V and the amount of implanted ions was 1×10 18 clTl−2.

The ion irradiation apparatus shown in FIG. 3 includes an ion source (41), a beam extraction section (42), an ion beam acceleration m (43
), mass separator (44), ion beam scanning unit (45)
It consists of an ion irradiation chamber (46) and an ion irradiation chamber (46).
The ion beam (47) extracted from the ion source (41) is irradiated onto the insulator (1) on which the circuit pattern mask (3) is superimposed, which is housed inside the insulator (46).

Specific Example 2> After superimposing a 0.2 mm thick stainless steel circuit pattern mask in which a through hole of 30 m1 in length and 0.5 mm in width was formed on the surface of a polyarylate film with a thickness of 100 μm, a third mask was formed. Using the ion beam irradiation device shown in the figure, an Ar+ ion beam was applied at a current value of 1.0 μAc.
Irradiation was carried out for about 22 hours under conditions of m-2 to produce a wiring board on which a conductor pattern corresponding to the shape of the above-mentioned through hole was formed. Note that the energy of the irradiated ions was 8 MeV, and the amount of implanted ions was 5×10” am −2 .

Specific Example 3 After superimposing a 0.2 mm thick stainless steel circuit pattern mask with a 30 mm long x 5 mm through hole formed on the surface of a 70 μm thick polyether ether ketone film, a third Using the ion beam irradiation device shown in the figure, NL+ ion beam was irradiated for about 11 hours at a current value of 2.0 μAcm-2.
A wiring board was prepared in which a conductor pattern corresponding to the shape of the above-mentioned through hole was formed. Note that the energy of the irradiated ions is 5
M e V , the amount of implanted ions is 5X10”c+n-
It was 2.

Concrete Example 4> A stainless steel circuit pattern mask with a thickness of O, 1 m+*, in which a through hole of 30 mm in length and 0.5 mm in width was formed, was superimposed on the surface of a polyetherimide film with a thickness of lOOμ, and then Using the ion beam irradiation device shown in Figure 3, a B+ ion beam was applied at a current value of 2.0 μAcm.
Irradiation was carried out for about 7 hours under the condition of -2 to produce a wiring board in which a conductor pattern corresponding to the shape of the above-mentioned through hole was formed. Note that the energy of the irradiated ions was IMeVs, and the amount of ions implanted was 3×1017effl''-2.

Evaluation Test> Regarding the wiring boards manufactured in Examples 1 to 4 above, the ion beam irradiated part (conductor pattern part) and the non-irradiated part (
Measure the surface resistance of the conductor pattern (parts other than the conductor pattern), and take the ion range calculated from the energy of the ion beam and the mass of the ion species used as the thickness of the conductor pattern, and use the measured value of the surface resistance as the volume resistivity. It was converted into The results are shown in the table below.

In general, a material with a volume resistivity of 10 -2 Ω·order or less is considered to be a good conductor, and a volume resistivity of 10 6 Ω·(total) order or more is considered an insulator.

From the table, it can be seen that a conductive pattern as a good conductor was formed on the surface of the film, which is an insulator, by ion beam irradiation.

<Effects of the Invention> In the wiring board of the present invention, the conductor pattern is made of the same type of material as the insulator and is formed as a continuous phase with the insulator by irradiating the surface of the insulator with an ion beam, thereby preventing delamination or warping. Furthermore, since the wiring board has a smooth surface with no protrusions, there is no risk of dust or dirt accumulating that would cause dielectric breakdown, etc. Furthermore, since no metal material is used, it is even more effective. It is possible to reduce the weight of the wiring board, and since no adhesive is used, it is possible to achieve even higher heat resistance, and various problems that conventional wiring boards have can be solved.

Furthermore, in the manufacturing method of the present invention, the surface of the insulator is irradiated with the ion beam using a circuit pattern mask that allows the ion beam to pass through only the portion corresponding to the predetermined circuit pattern. It is easy to form conductor patterns, and the overall process is reduced.
Moreover, since etching and plating processes are not required,
Wiring boards can be manufactured efficiently and at low cost.

[Brief explanation of the drawing]

FIG. 1 (cells are cross-sectional views showing the structure of an embodiment of the wiring board of the present invention, and FIG. 1) is a cross-sectional view showing the structure of a modified example, and FIG. 3 is an explanatory diagram showing the outline of the ion irradiation device used in the specific example, and FIG. 4 is a sectional view showing the structure of a conventional wiring board. (Middle) is a cross-sectional view showing a state in which a conductive thin film is laminated on an insulator via an adhesive layer in the conventional substrative method. (^) (A')...Wiring board, (1) ... Insulator, (2) ... Conductor pattern, (3) ... Circuit pattern mask, (31) ... Through hole. (47) ... Ion beam (b) (b) (C )

Claims (3)

[Claims] 1. At least an insulator made of resin material The surface is shaped by ion beam irradiation. A conductor pattern is provided. A wiring board characterized by: 2. At least an insulator made of resin material The part corresponding to the circuit pattern is marked on the surface. The circuit pattern through which the ion beam can pass through Place the pattern mask and create this circuit pattern. Ion beam is applied to the mask placement surface. irradiate to form a circuit pattern on the surface of the insulator. Forming a conductor pattern that corresponds to the turn A method of manufacturing a wiring board, characterized by: 3. Energy of ions irradiated by ion beam - is 0.2 MeV or more A method for manufacturing wiring boards.