JPS5834958B2 - Through-hole printed circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for manufacturing a through-hole printed circuit board using an electron beam-curable resin that is irradiated with an electron beam.

In recent years, the integration of electrical components has progressed, and conductors are provided on the front and back sides of a wiring board, and electrical connections are made by the conductors on each of the front and back sides.

Alternatively, printed wiring is provided on one side and printed resistance is provided on the other side.

Conventionally, when connecting such devices, a through hole is drilled through the wiring board at a portion where the front and back groove conductive layers face each other, or at a predetermined portion where the terminal of the printed resistor and the printed wiring face each other. The methods used include pouring conductive paint into the hole and making a through hole, or inserting a rod-shaped pin with conductive paint on the tip into the hole and transferring the conductive paint to the hole to make a through hole.

However, since the conductive paint used for this type of through hole is a thermosetting conductive paint, it is heated in a high-temperature oven at about 130 to 160 degrees for a long time to harden the conductive paint that adheres to the inside of the hole. It is necessary to heat and harden, which has poor productivity, and the insulating substrate deteriorates and warps due to high-temperature heating, so it is necessary to select an insulating substrate that can withstand high-temperature heating, and manufacturing is difficult because a high-temperature furnace is required. This method has drawbacks such as expensive and large-sized equipment, which inevitably imposes restrictions on the material of the insulating substrate on which the printed wiring is formed, and increases the cost of the through-hole printed circuit board.

The present invention was developed in view of the above, and uses an electron beam that passes through a conductive material, and uses a conductive paint that is a mixture of a conductive material and an electron beam-curable resin that hardens upon irradiation with the electron beam. An embodiment of the manufacturing method of the present invention will be described based on the drawings.

As shown in FIG. 1, a wiring board 1 has a printed wiring 3 on one side of an insulating substrate 2, and a printed resistor 4 on the other side by a well-known method, and the ends of the printed resistor 4 are coated with a conductive material and terminal 5, and a through hole 6 penetrating through the insulating substrate 2 is provided at a location where the connection portion between the terminal 5 and the printed wiring 3 faces, and as shown in FIG. A conductive material made of a mixture of a conductive substance such as silver powder and an electron beam-curable resin such as an unsaturated polyester or modified unsaturated polyester that generates active radicals and polymerizes and cures by irradiating it with an electron beam obtained using an electron beam accelerator. A rod-shaped pin 9 placed above the conductive paint tank 8 containing the paint 7 and slid up and down by a vertical sliding device is dipped into the conductive paint 7 of the conductive paint tank 8 through the through hole 6 and then raised. Ba,
The conductive paint 7 adhering to the rod-shaped pin 9 is transferred to the peripheral wall and upper and lower edges of the through hole 6.

Then, as shown in FIG. 3, the transferred conductive paint 7 is irradiated with an electron beam 11 from an electron beam irradiation device 10 for several seconds.
Allow the adhesive to harden.

Conductive paint 7 adhesively cured on the peripheral wall and upper and lower edges of the through hole 6
is a mixture of electron beam curable resin and conductive material.
By appropriately selecting the mixing ratio, it has good conductivity, and the printed wiring 3 and printed resistor 4 provided on the front and back surfaces of the insulating substrate 1 can be electrically connected via the hardened conductive paint 7.

As shown in FIG. 4, the electron beam 11 used in the present invention includes an operating section 12, a high voltage generator 13, an accelerator 14,
The electron beam can be obtained by a well-known electron beam irradiation device equipped with a scanner 15, a scanner magnet 16, and a vacuum pump 17, and irradiated through an irradiation window 18 on the front surface of the scanner 15.

As described above, according to the present invention, since through-hole connections of printed circuit boards are made using electron beam curable resin,
When curing the conductive paint, only electron beam irradiation is required, eliminating the problems of deterioration and warping of the insulating substrate caused by high-temperature heating. Materials can be selected.

Further, the time required for curing the conductive paint can be dramatically shortened compared to the time required for curing the conductive paint by irradiating it for several seconds, compared to when a thermosetting resin is used.

Furthermore, since it is cured by irradiation with electron beams, the conductive materials contained in conductive paints are highly conductive, except for special metals with a high specific gravity such as lead, which have a high absorption rate and are relatively difficult to pass through. It can be carried out without any obstacles such as the composition of the paint and the thickness of the coating.

[Brief explanation of drawings]

1 to 3 are manufacturing process diagrams of the present invention, and FIG. 4 is the constituent countries of the electron beam irradiation device used in the present invention, 1 is a wiring board, 3 is a printed wiring, 4 is a printed resistor,
Reference numeral 6 indicates a through hole, 7 indicates a conductive paint, and 11 indicates an electron beam.

Claims (1)

[Claims] 1. A through hole is formed in the opposite location of the conductor provided on both the front and back sides of an insulating substrate, and a conductive paint containing a mixture of a conductive substance and an electron beam curable resin that is cured by electron beam irradiation is applied to the peripheral wall and upper and lower edges of the through hole. A method for producing a through-hole printed circuit board, in which both groove electric bodies are electrically connected by adhering a conductive paint and irradiating the adhered conductive paint with an electron beam to cure the adhesive.