JP3942398B2 - Method for forming conductive pattern - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a conductive pattern used in the fields of electricity, electronics, semiconductors and the like.
[0002]
[Prior art]
Conventionally, when forming a conductive pattern on a continuous flexible insulating film 1, first, as shown in FIGS. 3 to 5, first, a plurality of first conductive patterns are formed on the surface which is the upper surface of the insulating film 1. 8 is screen-printed with a fluid conductive paste 9, and each first conductive pattern 8 is dried with a dryer 12 (see FIGS. 3A and 3B). A through hole 14 is drilled from above (see FIGS. 4A and 4B).
[0003]
After the through holes 14 are drilled in the first conductive pattern 8 in this way, the insulating film 1 is turned upside down, and the continuous flexible filter paper 15 is superimposed on the lower surface thereof, and the integrated insulating film 1 and filter paper are integrated. 15 is transported downstream, and a plurality of second conductive patterns 16 are screen-printed with a fluid conductive paste 17 on the back surface, which is the upper surface of the insulating film 1, and the first and second conductive patterns 8 and 16 are formed. Electrical conduction is established through the through-hole 14 and the conductive paste 17 (see FIGS. 5A and 5B).
[0004]
At this time, the conductive paste 17 flows into the through hole 14 for conducting connection. However, since the filter paper 15 has already adhered to the insulating film 1, the insulating film 1 and the table 7 may be contaminated with the conductive paste 17 to some extent. Can be prevented. After that, the insulating film 1 and the filter paper 15 are separated, the filter paper 15 is wound up, and the second conductive pattern 16 of the insulating film 1 is dried by the dryer 12 to form a continuous flexible insulating film 1. A conductive pattern can be formed.
[0005]
[Problems to be solved by the invention]
The conventional method for forming a conductive pattern is as described above. Since the filter paper 15 is simply overlapped with the insulating film 1, the insulating film 1 and the filter paper 15 are positioned due to the difference in frictional resistance during conveyance after screen printing. There are many cases that cause misalignment. When such misalignment occurs, the conductive paste 17 adheres to the filter paper 15, so that the conductive paste 17 contaminates the insulating film 1 and the like, and as a result, causes an appearance defect and a leakage defect.
[0006]
The present invention has been made in view of the above, and it is possible to prevent the insulating film and the filter paper from being misaligned during conveyance after printing, and to prevent the appearance failure or leakage failure of the insulating film or the like from occurring. An object of the present invention is to provide a method for forming a conductive pattern.
[0007]
[Means for Solving the Problems]
In the present invention, in order to solve the above problems, a method for forming a conductive pattern on a flexible insulating film,
A first conductive pattern is formed on the surface of the insulating film and dried. A through-hole is formed in the first conductive pattern, and the filter is placed on the surface with the insulating film turned upside down. Then, the second conductive pattern is formed on the back surface of the insulating film , and the first and second conductive patterns are electrically connected through the through holes .
[0008]
Of the insulating film and the filter paper that are in close contact with each other, the charging electrode connected to the power source is connected to the insulating film, the conductive plate is opposed to the filter paper, and the distance between the charging electrode and the conductive plate is set to 5 to 15 mm. It is preferable.
[0009]
Here, the first and second conductive patterns in the claims may be singular or plural, and may be any figure. In the formation of the first and second conductive patterns, the screen printing method is mainly employed, but other printing methods may be used. Further, in the electrostatic adhesion between the insulating film and the filter paper, a method such as corona discharge or induction charging can be appropriately used under the condition that the insulating film is not damaged.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. A method for forming a conductive pattern in the present embodiment will be described on the surface of a flexible insulating film 1 as shown in FIGS. One conductive pattern 8 is screen-printed with a conductive paste 9 and dried, a through hole 14 is drilled in the first conductive pattern 8, and the insulating film 1 is turned upside down so that a flexible filter paper 15 is formed on the lower surface thereof. And the second conductive pattern 16 is screen-printed with the conductive paste 17 on the back surface of the insulating film 1 to conduct the first and second conductive patterns 8 and 16 with the through hole 14. Electrical conduction is made with the paste 17, and then the insulating film 1 and the filter paper 15 are separated to dry the second conductive pattern 16 of the insulating film 1. .
[0011]
Next, a description will be given of a forming apparatus used for forming the conductive pattern. As shown in the figure, the forming apparatus for the conductive pattern includes an insulating film 1 wound around a roll of a rotary drive shaft from upstream to downstream, A filter paper 15 that is set upstream of the insulating film 1 and wound around a roll of a rotational drive shaft, a charging device 3, a table 7, a screen printing device 10, and a vertically movable punch 13 having a plurality of needles arranged ( In this regard, refer to FIG. 4), a take-up roll 18 for the filter paper 15, a dryer 12 for the insulating film 1 using infrared rays, hot air, and the like.
[0012]
Examples of the insulating film 1 include continuous long polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyester such as polyethylene naphthalate (PEN), polycarbonate, polyphenylene sulfide, and the like. Among these, polyethylene terephthalate having a thickness of 10 to 50 mm which is excellent in adhesion, dimensional stability, and bending resistance of the conductive pastes 9 and 17 and is stable to light and heat is suitable as a material.
[0013]
The filter paper 15 is formed, for example, with a synthetic fiber nonwoven fabric or porous cellulose paper so as to cover the surface of the insulating film 1 so as to cover the surface of the insulating film 1 or have a slightly smaller size, and has a thickness of 0.2 to 1.0 mm. It is formed. The thickness of the filter paper 15 is in the range of 0.2 to 1.0 mm because it is difficult to handle if it is thicker than the value in this range, and conversely, if it is too thin, the conductive paste 17 wraps around the back side of the filter paper 15. is there. The retained particle diameter of the filter paper 15 is 1 to 5 μm from the viewpoint of improving the passage of air and obtaining smoothness that does not adversely affect screen printing.
[0014]
As shown in FIG. 2, the charging device 3 is connected to a high voltage power source 4 and is electrically slidably contacted with a charging electrode 5 that is close to the upper insulating film 1 via a gap and a lower filter paper 15 to be charged. The SUS plate 6 which is a plate is provided, and the distance L between the charging electrode 5 and the SUS plate 6 forming the high electric field is 5 to 15 mm, preferably 8 to 12 mm, more preferably 10 mm. The reason why the distance L between the charging electrode 5 and the SUS plate 6 is in the range of 5 to 15 mm is that the charging electrode 5 may come into contact with the insulating film 1 when the distance L is less than 5 mm. On the other hand, when it exceeds 15 mm, the charge amount is weakened.
[0015]
The voltage value of the charging device 3 is preferably in the range of 1 to 10 kV, particularly 3 to 5 kV. This is because when the voltage is weaker than 1 kV, the insulation film 1 and the filter paper 15 are weakly adhered, and a positional deviation occurs. Conversely, when the voltage is higher than 10 kV, the adhesion between the insulating film 1 and the filter paper 15 is strong. This is because the insulating film 1 and the filter paper 15 cannot be easily separated. As the charging electrode 5, for example, a flat plate, a cylindrical electrode, a thin tungsten wire, a stainless steel wire, or the like can be used.
[0016]
The table 7 has a large number of suction holes arranged in the XY direction on the work surface, and the plurality of suction holes are connected to a vacuum device (not shown). For the screen printing apparatus 10, the punch 13, the take-up roll 18, and the dryer 12, well-known techniques are employed.
[0017]
In the above configuration, when forming a conductive pattern on the front and back surfaces of the continuous flexible insulating film 1, first, the roll-shaped insulating film 1 is conveyed onto the table 7 via a plurality of rollers 2 from upstream. The insulating film 1 is vacuum-adsorbed on the table 7, and a plurality of first conductive patterns 8 are screen-printed with a fluid conductive paste 9 on the surface of the upper surface of the insulating film 1 using a screen printing device 10. 7 to a downstream dryer 12 via a plurality of rollers 11 to dry each first conductive pattern 8 (see FIG. 3 for this point). As the conductive paste 9, 40 to 95% by weight of a conductive powder such as carbon, gold, silver, copper or nickel is contained in a binder such as polyester resin, polyurethane resin, epoxy resin or acrylic resin, and the volume resistivity is 0. A paste of 0.05 to 10 Ωcm is preferred.
[0018]
Next, the roll-shaped insulating film 1 is conveyed from upstream to the table 7 via a plurality of rollers 2, and the insulating film 1 is vacuum-adsorbed on the table 7 to pass through each first conductive pattern 8 on the surface. The hole 14 is drilled from above with a punch 13 and conveyed downstream (see FIG. 4 in this regard). At this time, the diameter of the through hole 14 to be drilled is preferably 0.1 to 0.5 mm. This is because if it is less than 0.1 mm, the needle of the punching machine 13 is easily broken, and conversely if it exceeds 0.5 mm, it is too large from the viewpoint of wiring density.
[0019]
Next, the insulating film 1 is turned upside down and wound into a roll shape, which is set again on the upstream rotary drive shaft, and a roll-shaped filter paper 15 is set upstream of the insulating film 1. When the insulating film 1 and the filter paper 15 are set in this way, the insulating film 1 and the filter paper 15 are respectively conveyed from the upstream through the plurality of rollers 2 in the downstream direction, and the filter paper 15 is superimposed on the lower surface of the insulating film 1. At the same time, the insulating film 1 and the filter paper 15 are charged and adhered by static electricity based on induction charging of the charging device 3 to be laminated and integrated, and conveyed onto the downstream table 7.
[0020]
When the integrated insulating film 1 and filter paper 15 are conveyed onto the table 7, the second conductive pattern 16 is screened on the back surface, which is the upper surface of the insulating film 1, by the fluid conductive paste 17. Screen printing is performed by the printing apparatus 10, and electrical connection is established by the through-holes 14 penetrating the first and second conductive patterns 8 and 16 and the conductive paste 17 flowing into the through-holes 14. The conductive paste 17 used at this time preferably has the same composition as the conductive paste 9 for the first conductive pattern 8 from the viewpoint of the stability of conduction, but may be different. Then, the integrated insulating film 1 and the filter paper 15 are conveyed downstream via the plurality of rollers 11, the filter paper 15 is wound around the take-up roll 18 and peeled off from the insulating film 1, and then the second of the insulating film 1. When the conductive pattern 16 is dried by the downstream dryer 12, the conductive pattern can be formed on the front and back surfaces of the continuous flexible insulating film 1.
[0021]
According to the above configuration, not only the filter paper 15 is simply superposed on the insulating film 1 but also these are closely adhered by applying static electricity to significantly improve the adhesion, so that the insulating film 1 and the filter paper 15 are transported after screen printing. It is possible to effectively suppress and prevent the occurrence of positional deviation due to the difference in the frictional resistance value. Accordingly, it is possible to suppress and prevent the conductive paste 17 attached to the filter paper 15 from contaminating the surface of the insulating film 1 and the like, thereby causing appearance defects and leakage defects.
[0022]
【Example】
Examples of the method for forming a conductive pattern according to the present invention will be described below.
First, a roll-shaped insulating film is transported onto a table via a plurality of rollers, and the insulating film is vacuum-adsorbed on the table so that a plurality of first conductive patterns are flown on the upper surface. The screen was printed, and the first conductive pattern was dried by conveying the insulating film from the table to a downstream dryer through a plurality of rollers. As the insulating film, PET having a width of 500 mm, a thickness of 25 μm, and a length of 200 m was used. As the conductive paste, commercially available DW-250H-5 [trade name, manufactured by Toyobo Co., Ltd.] was used. Each adsorption hole of the table was set to φ0.5 mm.
[0023]
Next, the roll-shaped insulating film is conveyed again from the upstream to the table via a plurality of rollers, and the insulating film is vacuum-adsorbed on the table, and a φ0.2 mm through hole is formed in each first conductive pattern on the surface. Was drilled from above with a punch and transported downstream.
[0024]
Subsequently, the insulating film was turned upside down and wound into a roll shape, which was set again on the upstream rotary drive shaft, and a roll-shaped filter paper was set upstream of the insulating film. As the filter paper, one having a reserved particle diameter of 2 μm, a width of 400 mm, a thickness of 0.5 mm, and a length of 200 m was used. When the insulating film and filter paper are set, these insulating film and filter paper are transported in the table direction from the upstream via a plurality of rollers, and the filter paper is superimposed on the lower surface of the insulating film. The charging device was charged and brought into close contact with static electricity and integrated and transported onto a downstream table. A high DC voltage of 4 kV was applied to the charging electrode of the charging device.
[0025]
After transporting the integrated insulating film and filter paper onto the table, vacuum-adsorb on the table and screen-print a second conductive pattern on the back, which is the top surface of the insulating film, with a fluid conductive paste. Electrical conduction was made with a through-hole penetrating the two conductive patterns and a conductive paste. The conductive paste used at this time was the same as the conductive paste for the first conductive pattern. Then, the integrated insulating film and filter paper are conveyed downstream through a plurality of rollers, the filter paper is wound on a take-up roll and separated from the insulating film, and then the second conductive pattern is removed by a downstream dryer. Dried.
[0026]
According to the present embodiment, the conductive paste adhered to the filter paper contaminates the insulating film and the like through the through holes, thereby eliminating the problem that the appearance defect and the leakage defect occur (conventionally 10 to 30% occurred). It was confirmed that it can contribute to the improvement of the product rate.
[0027]
【The invention's effect】
As described above, according to the present invention, the insulating film is turned upside down, and the filter paper is overlapped on the surface thereof and electrostatically adhered by the static electricity of the charging device. Therefore, the insulating film and the filter paper are transported after the second conductive pattern is printed. This prevents the occurrence of misalignment and effectively prevents the occurrence of defective appearance or leakage in the insulating film or the like.
[Brief description of the drawings]
FIG. 1 is an overall explanatory view showing an embodiment of a method for forming a conductive pattern according to the present invention.
FIG. 2 is a main part explanatory view showing an embodiment of a method for forming a conductive pattern according to the present invention.
FIG. 3 is an explanatory view showing a conventional method for forming a conductive pattern. FIG. 3A is a general view showing a state in which a first conductive pattern is screen-printed with a conductive paste on the surface of an insulating film and dried. (B) is explanatory drawing which shows the 1st conductive pattern in (a) figure.
4A and 4B are explanatory views showing a conventional method of forming a conductive pattern, in which FIG. 4A is a general view showing a state in which a through hole is drilled in the first conductive pattern from above, and FIG. It is explanatory drawing which shows a hole.
FIG. 5 is an explanatory view showing a conventional method for forming a conductive pattern. FIG. 5 (a) shows an integrated insulating film and filter paper conveyed, and a second conductive pattern is screen-printed with a conductive paste on the back surface of the insulating film. Then, the first and second conductive patterns are conducted through through holes, the insulating film and the filter paper are separated, the filter paper is taken up, and the second conductive pattern is dried by a dryer, (b) The figure is an explanatory view showing a second conductive pattern in FIG.
[Explanation of symbols]
1 Insulating film 3 Charging device 4 High voltage power supply
5 Charging electrode 6 SUS plate (conductive plate)
7 Table 8 First conductive pattern 9 Conductive paste 10 Screen printing device 12 Dryer 14 Through hole 15 Filter paper 16 Second conductive pattern 17 Conductive paste

Claims (1)

A method of forming a conductive pattern on a flexible insulating film, wherein a first conductive pattern is formed on the surface of the insulating film and dried, a through hole is formed in the first conductive pattern, and the insulating film is turned upside down. On the other hand, filter paper is placed on the surface and electrostatically adhered by the static electricity of the charging device , and then the second conductive pattern is formed on the back surface of the insulating film , and the first and second conductive patterns are electrically connected through the through holes . A method for forming a conductive pattern, comprising:

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