JPS5815958B2 - Manufacturing method for double-sided through-hole flexible printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a double-sided through-hole flexible printed wiring board that is superior in workability and can provide a high-quality double-sided through-hole flexible printed wiring board.

Double-sided through-hole flexible printed wiring boards, which are generally used mainly for industrial equipment, are manufactured using the copper through-hole construction method, which is based on a copper-clad glass epoxy base material in which glass cloth is impregnated with an epoxy thermosetting resin and laminated with copper foil. It was manufactured using a similar method.

However, with the recent trend toward smaller and thinner consumer devices, the density of circuits on printed circuit boards has increased, and the use of through-holes on both sides has progressed, and as devices have become lighter, printed circuit boards have also become thinner and more flexible. It is progressing.

Therefore, when applying double-sided through-hole flexible printed wiring boards manufactured using the conventional double-sided through-hole manufacturing method to consumer equipment, which is a cost-critical product, the cost
Manufacturing time was a particular obstacle.

Usually, in screen printing for pattern formation, etching resist ink is applied only on the copper foil 2 on the surface of the insulating substrate 10 on the screen plate 3° 5 printing stage 4, as shown in FIG.
Printed using printing ink 5.

However, as shown in Figure 2, if you use the same method as above to perform two-line printing on a thin film that has already been coated with through-holes, depending on the diameter of the through-holes, the The ink 5 wraps around the back surface of the insulating substrate 1 (the opposite surface to the printing surface), and is also transferred onto the printing table, leaving the printing ink 5 in unnecessary areas.
This required work to plan out the removal of the particles, resulting in poor productivity.

The present invention eliminates the drawbacks of the prior art as described above.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 9 of the drawings.

9 First, the features of the present invention will be explained with reference to FIGS. 3 and 4.

That is, a developed image film 5 smaller than the diameter of the through-hole plating hole is formed on a portion corresponding to the through-hole plating hole of the circuit pattern 8 as a circuit forming screen plate 7, and when screen-printing the printing ink 10 of the etching resist, the printing ink 10 At the same time as the circuit pattern is screen printed, the printing ink 10 is applied to the sulfone plating hole 11 or the hole wall, and then the opposite side is similarly screen printed to apply the etching resist printing ink 10. is applied to the circuit pattern and the through-hole plating holes 11 or the hole walls, and the copper outside the printing ink 10 is removed using an etching solution such as ferric chloride or cupric chloride to obtain a predetermined through-hole circuit. It is something.

Specific examples thereof will be described below with reference to FIGS. 5 to 9.

7 First, as shown in FIG. 5, a laminate with a thickness of about 0.17 mm was constructed by pasting copper foil 14 on both sides of a 50 μm thick base film 120 made of polyimide, polyester, glass epoxy, etc. using an adhesive 13.

As shown in FIG. 6, through holes 15 are formed in this laminate using a drilling machine or a press die.

In this case, the diameter of the through-hole hole 15 is approximately 0.4 to 0.5
There are those of mm and those of 0.6 ynm or more.

Next, as shown in FIG. 7, through-hole plating holes 11 are formed by electroless plating or electroplating.

Thereafter, as shown in FIG. 8, an etching resist 10 is formed in the through-hole plating holes 11 and in a predetermined circuit pattern using the screen plate 7 shown in FIGS. 3 and 4.

At this time, if the through-hole plating hole 11 has a diameter of 0.4 to 0.5 mm, the printing ink of the etching resist 10 will not go around to the other side even if the developed image film 9 is not formed on the screen plate 7. The printing ink will not go around the through-hole plating holes 11 whose diameter is 0.6 mm or more.

Therefore, a developed image coating 9 is required on the screen plate 1 corresponding to the through-hole plating holes 11.

In addition, when polyethylene terephthalate is used as the material of the screen plate 7, the number of meshes is 300 meshes, and the printing thickness of the printing ink 10 is 7 to 8 μm, the size of the developed image film 9 is a through-hole plating hole diameter of 0.8 mm.
, 10mm, 1.2mrn, 2.0-a, diameter 0.4-0.5 mm for Oim, 0.6-0.7
mm.

0.7~0.8mm, 1.4~1.5-2.4~2
．． 5 rim is appropriate.

The material on which the etching resist 10 has been applied in this manner is etched as shown in FIG. 9, and the etching resist 10 is removed.

After that, cover sheet film and solder adhesive ink are applied to complete the double-sided through-hole flexible printed wiring board.

As described above, according to the method for manufacturing a double-sided through-hole flexible printed wiring board of the present invention, etching resist can be printed easily and reliably by screen printing, greatly improving work efficiency, and etching resist can be removed from unnecessary areas. It has the advantage of being able to provide products of extremely high quality because it does not adhere, making it a valuable product in industry.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a general etching resist screen printing method, Fig. 2 is a cross-sectional view of a conventional double-sided through-hole flexible printed circuit board when etching resist is printed, and Fig. 3 is a double-sided through-hole film according to the present invention. A top view of the main parts of a screen plate for etching resist printing in the method for producing a xipul printed wiring board, FIG. 4 is a cross-sectional view when printing using the same screen plate, and FIGS. 5 to 9 are in accordance with the present invention. FIG. 3 is a cross-sectional view of each step showing the method. 7...Screen plate, 8...Circuit pattern, 9...Developed image film, 10...
Etching resist printing ink, 11...Through hole plating hole, 12...Base film, 1
3...Adhesive, 14...Copper foil, 15.
...Through hole.

Claims (1)

[Claims] 1. Create specified through-hole holes in a double-sided copper-clad flexible film, plate the entire surface and the through-hole holes, apply Elatin Bregs printing ink to the circuit pattern and through-hole plating holes by screen printing, and remove unnecessary conductors by etching. The method for producing a double-sided through-hole printed wiring board is characterized in that when applying the etching resist printing ink, a screen plate is used on which a developed image film smaller than the diameter of the through-hole plating holes is formed on a portion corresponding to the through-hole plating hole diameter. A method for manufacturing a double-sided through-hole flexible printed wiring board.