JPH08153947A - Method and device for forming wiring film on printed board - Google Patents

Abstract

PURPOSE: To quickly form a wiring film on a board without requiring any troublesome treatment, such as etching, etc., in such a simple way that the forming work can be carried out on a work bench. CONSTITUTION: A wiring film 13 composed of a toner film is formed in such a way that, after the latent image of the same pattern as that of the wiring film is formed by exposing the surface of an electrostatically charged photoreceptor in accordance with the information of the pattern and a toner film having the pattern is formed by developing the surface of the photoreceptor with conductive toner. Then the toner film on the surface of the photoreceptor is transferred to and printed on the surface of the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a wiring film on a printed circuit board and a wiring film forming apparatus used for the same.

[0002]

2. Description of the Related Art A printed circuit board is formed by forming a wiring film made of, for example, copper foil in a desired pattern on an insulative substrate, and various electronic parts such as transistors, ICs and resistors are mounted on the printed circuit board. Circuit, a television receiver,
It is used in electronic devices such as personal computers and various other devices, and the production volume is increasing.

Conventionally, a printed circuit board is prepared by laminating a copper foil on the surface of the board, coating the surface of the copper foil with a resist film, and exposing the resist film to light through a mask. Then, the resist film is irradiated and subjected to photosensitization, and then the resist film is developed to form a negative pattern on the wiring film to be formed. Using the resist film as a mask, for example, a ferric chloride-based etching solution is used. It was made by selectively etching copper foil.

[0004]

By the way, the above-mentioned method of forming a wiring film on a printed circuit board is very troublesome.
First of all, designing the pattern of the wiring film by making full use of a computer etc., make a mask of the same pattern as that pattern, and then, on the copper foil surface of the laminated substrate in which the copper foil is laminated on the substrate surface, the resist film is formed. And irradiate the resist film with light through the mask to perform photosensitization,
This is because it requires a troublesome work of performing a development process, and then performing etching with an etching solution that can be called a powerful drug using the resist film as a mask.

As described above, the need for the troublesome work naturally leads to the cost increase of the printed circuit board, the time required for the trial manufacture of the printed circuit board becomes longer, and the time required from the development to the commercialization becomes longer. It also brings problems. Moreover, special machines that perform photosensitization, development, and etching,
It requires a processing room equipped with equipment, which is absolutely impossible in the office. Moreover, the etching liquid can be said to be a powerful medicine, and its handling requires a special engineer who is familiar with chemistry, and cannot be handled by a mere electronic circuit design engineer. And
Not only is it very costly to process the etching solution, etc., but even if the waste solution is processed, it is unavoidable to cause environmental pollution.

In other words, conventionally, an electronic circuit design engineer can make a circuit design and a pattern design of a wiring film of a printed circuit board consistently by making full use of a computer or the like, and can further produce an etching mask pattern. However, after that, it was impossible because the technology completely different from the electronic circuit design technology had to be used.

The present invention has been made in order to solve such problems, and it is quick and easy without the need for troublesome processing such as etching and, for example, even if there is no special facility. An object of the present invention is to provide a novel method for forming a wiring film on a printed circuit board, which enables the formation of a wiring film on a desk or the like, and a wiring film forming apparatus used for carrying out the method.

[0008]

According to a first aspect of the present invention, there is provided a method for forming a wiring film on a printed circuit board, which comprises exposing a surface of a charged photoconductor to light according to information about the pattern of the wiring film to be formed thereon. Make a latent image of the same pattern as
A toner film having the above pattern is formed by developing toner on the surface of the photoconductor with toner powder having conductivity, and the toner film on the surface of the photoconductor is transferred to the surface of the substrate on which the wiring film is to be formed. Then, the wiring film made of a toner film is formed by baking. According to a second aspect of the present invention, there is provided a method of forming a wiring film on a printed circuit board according to the first aspect, wherein the toner powder is mainly composed of copper, silver or gold.

According to another aspect of the present invention, there is provided a wiring film forming apparatus for a printed circuit board, wherein a drum-shaped rotatable photoconductor, a charger for charging the surface of the photoconductor, and a charged surface of the drum-shaped photoconductor. A light source that forms a latent image by irradiating on a line parallel to the rotation axis of the photoconductor based on pattern information to be formed, and a surface of the photoconductor on which the latent image is formed with conductive toner powder. It is characterized by having a developing device for developing, a transfer part for transferring the toner film formed on the surface of the photoreceptor by the development to a substrate, and a fixing part for printing the toner film.

[0010]

According to the method of forming a wiring film on a printed circuit board of claim 1, by selectively irradiating the surface of the charged photosensitive member with light based on information of the pattern of the wiring film to be formed, the pattern is formed. Can form a latent image as
By developing the surface of the photoconductor on which the latent image is formed with a toner having conductivity, a toner film having the above pattern can be formed on the surface of the photoconductor, and the toner film is used as a wiring film. By transferring to a substrate to be formed and baking, a wiring film having a pattern to be formed can be formed on the substrate. Therefore, the printed circuit board can be obtained immediately, that is, in a very short time of several seconds to several minutes, only if the pattern information of the wiring film is provided. Therefore, the period from the development to the completion of the printed circuit board can be shortened, which is very convenient especially for the trial manufacture of the printed circuit board.

Further, there is no need for photographic processing or etching processing using a chemical solution such as resist coating, photosensitization, and development. Therefore, since no liquid chemicals are used, low pollution and safe printing of printed circuit boards are possible. Production can be done, for example, on a desk rather than in a specialized facility. Of course,
It requires absolutely no high-level chemical expertise in the manufacture of printed circuit boards, so that electronic circuit development engineers can automatically create printed circuit boards if they give information about their own designed circuit patterns. You can Therefore, the cost of materials and equipment used for manufacturing the printed circuit board can be remarkably reduced, and the manufacturing cost can be remarkably reduced.

According to the method for forming a wiring film on a printed circuit board of the present invention, since the toner forming the wiring film is mainly composed of copper, silver or gold having high conductivity, a good wiring film having no large parasitic resistance can be obtained. Can be formed. According to the third aspect of the present invention, the surface of the rotatable drum-shaped photoconductor can be charged by the charger, and the surface of the photoconductor is formed on the basis of the pattern information of the wiring film to be formed. The latent image corresponding to the pattern information is formed by repeating the formation of a latent image for one line by the light source that exposes in parallel with the rotation axis every time the drum-shaped photosensitive member is rotated by a predetermined pitch (sub-scanning). can do. Then, since the surface of the photoconductor is developed with the conductive toner by the developing device, it is possible to form a state in which the toner is formed on the latent image on the surface of the photoconductor.
Since the toner can be transferred to the surface of the substrate and baked in the fixing unit, the wiring film made of the toner film can be formed according to the given pattern information. Therefore,
The method for forming a wiring film on a printed circuit board according to claim 1 or 2 can be implemented.

[0013]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is a sectional view showing one embodiment of a method for forming a wiring film on a printed circuit board according to the present invention. In the drawings, reference numeral 1 denotes a drum-shaped photosensitive member, which is rotatable. 2 is the photoconductor 1
It is a charger that charges the surface prior to static elimination. Reference numeral 3 denotes a static elimination lamp, which eliminates static electricity from the surface of the photoconductor 1. A cleaning unit 4 cleans the surface of the photoconductor 1. 5 is a photoconductor 1
A charging device 6 for charging the surface is a light source for exposure, and when the emitted light thereof scans a pattern drawing (original) 7 on which a pattern of a wiring film to be formed is drawn, the reflected light is reflected by the photoconductor 1. The surface of the photoconductor 1 is irradiated with the light through the lens 8 to scan (main scan) the surface of the photoconductor 1 in parallel with its rotation axis.

As a result, a latent image is formed on the surface of the photoconductor 1. A latent image for one line is formed by one main scan, and when one main scan is completed, the photoconductor 1 is rotated (sub-scanned) by a predetermined pitch, and the main scan and the sub-scan are alternately repeated. A latent image of a pattern for one document is formed on the surface of the photoconductor 1. A developing unit 9 develops a portion of the surface of the photoconductor 1 on which a latent image is formed, with a conductive toner 13. By this development, the toner film 13 is formed on the latent image on the surface of the photoconductor 1.

Reference numeral 10 denotes a transfer portion (charger) which charges a substrate (for example, a Mylar sheet) 11 on which a wiring film is formed from the back surface to transfer the toner film 13 on the surface of the photosensitive member 1 to the surface of the substrate 11. is there. 12 is the transferred toner film 1
A fixing unit for fixing 3 to the surface of the substrate by heating.

FIGS. 2A and 2B are explanatory views of an example of the toner. FIG. 2A shows a state before printing and FIG. 2B shows a state after printing. The toner 13 is made of metal particles such as copper. It is desirable that the particle size be 10 μm or more so as not to enter the human body and cause harm. When the toner 13 is formed of only copper powder, for example, a substrate (for example, Mylar sheet) 11 having a surface coated with a polymer resin 14 is used. This is because the toner made of copper is heated to bond the polymer resin 14 to the substrate 13 as an adhesive. In this case, it is advisable to apply pressure to the toner film 13 in the fixing unit 12 at the time of fixing to promote the adhesion between the metal particles made of copper. The state after the fixing by the heat accompanied by the pressurization is completed is as shown in FIG.

FIGS. 3A and 3B are explanatory views of another example of the toner. FIG. 3A shows a state before printing and FIG. 3B shows a state after printing. The toner of this example is based on a granular body in which polymer resin 14a is coated on the surface of metal particles 13a made of, for example, copper, and solder particles 15 are mixed therein. And in this toner, as shown in FIG.
As shown in (B), the solder particles 15 serve as a binder for adhering the metal particles 13a to each other, and the polymer resin 14a formed on the surfaces of the metal particles 13a adheres the toner film based on the metal particles 13a to the substrate 11. Become a binder to do. Since the polymer resin between the metal particles 13a is almost burned by heating, the metal particles are not electrically insulated from each other, and the electrical conductivity of the wiring film made of toner is sufficiently high. You can When such toner is used as the wiring film material, it is not necessary to coat the surface of the substrate 11 with the polymer resin 14.

As the toner, it is also possible to use an ordinary black toner used in an ordinary copying machine or printer (for example, a laser printer), which is appropriately mixed with metal powder made of copper, for example. In this case, the copper film can be bonded to the substrate 11 by utilizing the fixing power of the black toner.

FIG. 4 is a perspective view for simply explaining the principle of the present invention. To briefly explain the present invention, the principle of a laser printer or a copying machine is effectively used, and a toner having conductivity that can be used as a wiring film is used. The wiring film is formed by developing on the surface of the drum-shaped photoconductor 1 on which the latent image is formed by exposing the original document 7 to a pattern, and transferring the developed toner 13 to the substrate 11 and fixing it. .

In the above embodiment, metal particles made of copper are used as the main material of the toner, but metal particles such as silver or gold may be used instead. Further, in the above-mentioned embodiment, the Mylar film was used as the substrate, and the wiring film was formed on the surface thereof,
The wiring film may be formed on a substrate that is thicker than the Mylar film, such as Bakelite, paper epoxy, or glass epoxy. In the above-described embodiment, the pattern information of the wiring film to be formed is drawn in the drawing (original) 7, optically read and exposed to the wiring film forming apparatus.
However, the pattern information may be given to the wiring film forming apparatus in the form of an electric digital signal, and the light source may be blinked by the signal to perform the exposure. This way,
It is possible to save the trouble of printing out the pattern (original) 7 by printing out the pattern information created by a personal computer or the like, and there is no fear of noise due to dust or the like during optical reading. As described above, the present invention can be carried out in various modes, and there can be various variations.

[0021]

According to the method of forming a wiring film on a printed circuit board of claim 1, the information of the pattern of the wiring film to be formed is selectively irradiated with light on the surface of the charged photoconductor to form the pattern. Can form a latent image as
By developing the surface of the photoconductor on which the latent image is formed with a toner having conductivity, a toner film having the above pattern can be formed on the surface of the photoconductor, and the toner film is used as a wiring film. By transferring to a substrate to be formed and baking, a wiring film having a pattern to be formed can be formed on the substrate. Therefore, the printed circuit board can be obtained immediately, that is, in a very short time of several seconds to several minutes, only if the pattern information of the wiring film is provided. Therefore, the period from the development to the completion of the printed circuit board can be shortened, which is very convenient especially for the trial manufacture of the printed circuit board.

Further, there is no need for photographic processing or etching processing using a liquid such as resist coating, photosensitization and development. Therefore, since no liquid chemicals are used, low pollution and safe printing of printed circuit board are possible. Production can be done, for example, on a desk rather than in a specialized facility. Of course,
The printed circuit board does not need to have a high degree of chemical special knowledge, and if an electronic circuit development engineer gives a circuit pattern designed by himself as information, the printed circuit board can be automatically formed. Therefore, the cost of materials and equipment used for manufacturing the printed circuit board can be remarkably reduced, and the manufacturing cost can be remarkably reduced, and the pollution can be reduced.

According to the wiring film forming method of the printed circuit board of the second aspect, since the toner forming the wiring film is mainly made of copper, silver or gold having high conductivity, a good wiring film having a small parasitic resistance can be obtained. Can be formed. According to the third aspect of the present invention, the surface of the rotatable drum-shaped photoconductor can be charged by the charger, and the surface of the photoconductor is formed on the basis of the pattern information of the wiring film to be formed. Forming a latent image according to the pattern information by repeating formation of a latent image for one line by a light source in parallel with the rotation axis every time the photoconductor on the drum is rotated by a predetermined pitch (sub scanning). You can Then, since the surface of the photoconductor is developed with the conductive toner by the developing device, a state in which the toner is formed on the latent image on the surface of the photoconductor can be created, and the toner is formed in the transfer unit and the fixing unit. Since the toner can be transferred onto the surface of the substrate and baked, the wiring film made of the toner film can be formed according to the given pattern information. Therefore, claim 1
Alternatively, the method 2 of forming a wiring film on a printed circuit board can be carried out.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a method for forming a wiring film on a printed board according to the present invention.

2A and 2B show an example of a toner used for carrying out the present invention. FIG. 2A shows a state before baking, and FIG. 2B shows a state after baking.

3A and 3B show another example of the toner used for carrying out the present invention. FIG. 3A shows a state before baking and FIG. 3B shows a state after baking.

FIG. 4 is a perspective view briefly explaining the principle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 5 Charging device 6 Light source 9 Developing device 11 Substrate 10 Transfer part (charging device) 12 Fixing part 13 Toner

Claims (3)

[Claims] 1. A latent image having the same pattern as the pattern is formed by exposing the charged surface of the photoconductor in accordance with the information of the pattern of the wiring film to be formed, and the above-mentioned photosensitization is performed using conductive toner powder. A toner film having the above pattern is formed by developing toner on the surface of the body, and the toner film is formed by transferring the toner film on the surface of the photoconductor to the surface of the substrate on which the wiring film is to be formed and baking it. Wiring film forming method for printed circuit board, characterized by forming wiring film 2. The method for forming a wiring film on a printed circuit board according to claim 1, wherein the toner powder is mainly composed of copper, silver or gold. 3. A drum-shaped rotatable photoconductor, a charger for charging the surface of the photoconductor, and a line on the charged surface of the drum-shaped photoconductor parallel to the rotation axis of the photoconductor. Is irradiated on the basis of pattern information to be formed to form a latent image, a developing device for developing the surface of the photoreceptor on which the latent image is formed with conductive toner powder, and 3. The printed circuit board according to claim 1, further comprising: a transfer unit that transfers the toner film formed on the surface of the photoconductor to the substrate, and a fixing unit that prints the transferred toner film on the substrate surface. Wiring film forming apparatus used for carrying out wiring film forming method