JPH08181417A - Manufacture of circuit material - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of a circuit material which constitutes a circuit substrate and can make a large current flow without being limited by a thickness of a conductor economically by using a molding die commonly. CONSTITUTION: The title method is for manufacturing a circuit material constituting a circuit substrate by setting a conductor 11 in a molding die 30 and then injecting resin into the die 30 for making molding resin and the conductor 11 integral. The molding die 30 wherein a plurality of projection parts 31b having the same height are arranged in at least one of surfaces holding the conductor 11 therebetween at an interval which is narrower than a minimum conductor width of the conductor 11 is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method suitable for producing a circuit material which constitutes a high current circuit board using a relatively thick metal plate as a circuit conductor.

[0002]

2. Description of the Related Art An ordinary circuit board is manufactured by pattern etching a copper foil attached to the surface of an insulating board, but a relatively thick conductor such as a large current circuit board or a power supply circuit is required. In this case, a punched circuit conductor is formed by punching from a copper plate, and this is laminated and integrated with an insulating substrate to manufacture a circuit board. In this case, in order to make the positional relationship of a plurality of conductors (hereinafter, circuit conductors) forming the circuit pattern constant,
A plurality of circuit conductors forming a required circuit pattern are arranged in the edge frame conductor, and each circuit conductor is fixed to the edge frame conductor or an adjacent circuit conductor by a thin bridge. In addition, one of the manufacturing methods for integrating a circuit conductor and an insulating substrate into a circuit substrate is casting,
A method of manufacturing a circuit board has been proposed in which a conductor is embedded in a thermosetting molding resin and integrated by a resin molding means such as transfer molding or injection molding (see JP-A-5-291715).

[0003]

In the method of embedding and integrating a conductor to be a circuit by using a resin molding means, in order to prevent the conductor pattern from being deformed by the injection pressure at the time of injecting the resin into the molding die. In addition, it is necessary to fix the conductor inside the molding die, but in the conventional manufacturing method, since a dedicated molding die is required for each conductor pattern, the economical efficiency during production in a small lot is deteriorated.

[0004]

The invention according to claim 1 provides a method for manufacturing a circuit material which solves the above-mentioned problems, in which a conductor is set in a molding die, and then a resin is injected into the die. When manufacturing a circuit material in which a molding resin and a conductor are integrated, a plurality of convex parts having the same height as a molding die are arranged on at least one of the surfaces sandwiching the conductor regardless of the pattern of the conductor. It is characterized by using a mold. Here, "irrespective of the pattern" means that convex portions are arranged also in a portion where conductors do not exist, that is, between conductors. Here, as the most desirable arrangement pattern of the convex portions, for example, a pattern in which the entire surface sandwiching the conductor of the mold is arranged at a predetermined pitch in the vertical and horizontal directions, for example, in a grid pattern or a zigzag pattern. In addition, it is desirable that the convex portions are formed with an interval narrower than the minimum width of the conductor (circuit conductor) to be a circuit.

According to a second aspect of the method for manufacturing a circuit material, the conductor is set in a molding die, and then resin is injected into the die,
When manufacturing a circuit material in which a molding resin and a conductor are integrated, as a molding die, a molding die having a groove that communicates with the resin injection portion is provided across at least one of the surfaces sandwiching the conductor. It is a manufacturing method. Here, as the grooves, only the grooves extending in the vertical direction may be used, but it is preferable that a plurality of horizontal grooves intersecting with the vertical grooves be provided and arranged in a mesh shape. The pitch of the grooves is preferably smaller than the minimum width of the gap between the conductors. The depth of this groove is preferably 0.5 to 2 mm, particularly 0.5 to 1 mm. The reason is that at least 0.5 mm is required to use the groove as a flow path for the molding resin, and when the groove becomes deeper in the stacking in the subsequent step, bubbles are generated or the composite substrate becomes too heavy. This is because a problem will occur. The depth of the groove is preferably as shallow as possible, but considering the formability, it is preferably 0.5 to 1 mm. (The experiment is 0.
It was performed at 5 mm. )

[0006]

According to the invention of claim 1, as described above, the arrangement pattern of the convex portions provided on the surfaces of the molding die on which the circuit conductor is sandwiched is independent of the conductor pattern. Therefore, irrespective of the pattern shape of the conductor, these convex portions reliably contact the circuit conductor with the molding die closed and fix the circuit conductor. Further, since the groove formed along with the protrusion serves as a resin flow path, it is possible to fill the molding resin between the conductor patterns. Further, according to the second aspect of the present invention, since the molding die provided with the groove crossing the conductor is used, the molding resin can be filled between the conductor patterns through the groove. When the circuit material of these inventions is used, it can be used as a circuit board itself, and the circuit material can be laminated to form a multilayer circuit board.

[0007]

【Example】

(Embodiment 1) Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a perspective view of an embodiment of a circuit material manufactured by the method for manufacturing a circuit material according to the present invention.
The circuit material 41 is formed by integrating the conductor 11 shown in FIG. 2 with a molding resin in the molding die 30 shown in FIG.

The conductor 11 is made of a copper plate, and its surface is subjected to blackening treatment in order to enhance the adhesiveness with the molding resin during the resin molding in the subsequent step. As shown in FIG. 2, the conductor 11 has a plurality of circuit conductors 14 fixed inside a frame conductor 13 by a bridge 13a and a bridge 14a, and is formed by punching. The bridge 13a connects the edge frame conductor 13 and the circuit conductor 14, and the bridge 14a connects between the circuit conductors 14. Here, the circuit conductor 14
Form a circuit pattern, and the edge frame conductor 13 and the circuit conductor 1
4, the bridges 13a and 14a form a conductor pattern. The material of the conductor 11 is not limited to copper, but may be a single metal or alloy such as aluminum, iron or stainless steel, or a material obtained by plating zinc, tin, nickel or the like. As the surface treatment of the circuit conductor 11, in addition to the blackening treatment, degreasing or roughening, coupling agent treatment, application of an adhesive, or the like may be performed to improve the adhesion with the molding resin.

As shown in FIG. 3, the molding die 30 is composed of a fixed die 31 and a movable die 32. On the surface of the fixed die 31, convex portions 31b having the same height for fixing the punched conductors 11 are formed so as to be regularly arranged in the vertical and horizontal directions except for the resin injection portion vicinity 31c. That is, the convex portion 31b is arranged on the entire portion of the fixed die 31 that sandwiches the conductor 11. The convex portion 31b has a flat head portion and is arranged at an interval smaller than the minimum width of the circuit conductor 14. Therefore, all the circuit conductors 14 always hit the convex portions 31b and are supported and fixed. A groove 31a is formed between these convex portions 31b. These grooves 31a include a groove extending in the vertical direction and a groove extending in the horizontal direction orthogonal to these, and are arranged in a mesh shape as a whole. These grooves 31
a communicates with the resin injection hole 20a. The circuit material 41 is formed by setting the conductor 11 on the inner surface of the movable die 32, closing the die, and molding resin into the fixed die 31 through the resin injection hole 20.
When filled from a, the molding resin passes over the conductor 11 through the groove 31a of the fixed mold 31, and passes through the cavity 20 (fixed mold 3
1 and the movable die 32). That is, the void portion 20b other than the conductor pattern of the conductor 11
Is also filled.

The molding resin is a thermoplastic resin such as polyethylene terephthalate, polyphenylene sulfide or polyether imide, or a thermosetting resin such as epoxy, unsaturated polyester or diallyl terephthalate, which has good heat resistance at the soldering temperature. Is good. It is preferable to add a glass filler or the like so that the molding resin has a linear expansion coefficient similar to that of the material forming the conductor 11 in order to prevent deformation such as warpage of the circuit material 41 after molding. It is preferable to adjust the expansion coefficient.

The circuit material 41 thus formed is
As shown in FIG. 1, the circuit conductor 14 connected by the bridge 14 a is integrated with the molding resin 42. Recesses 42 a (corresponding to the protrusions 31 on the surface of the fixed die 31) are regularly arranged on the upper surface of the circuit material 41. Further, between these concave portions 42a, convex ridges 42c corresponding to the grooves 31a of the fixed die 31 are formed in an increasingly mesh shape. In addition,
The circuit conductor 14 in FIG. 1 shows the shape of the dotted line portion in FIG. 2 as viewed from above.

FIGS. 4A and 4B are a plan view and a sectional view taken along line AA of a processed circuit material 41a formed by processing the above-mentioned circuit material 41 so as to form a desired electric circuit. . As shown in FIG. 4A, the processed circuit material 41a is drilled into the through holes 43 and 44 at the positions of the bridges 14a and 13a.
Is provided, the bridges 14a and 13a are cut, and each circuit conductor 14 is electrically independent.

By using the above-mentioned circuit material 41a, a double-sided circuit board can be manufactured as follows. After the processed circuit material 41a is subjected to surface treatment such as degreasing and roughening,
A double-sided circuit board is manufactured as follows using the molding die 50 shown in FIG. That is, between the fixed die 51 of the molding die 50 and the inner surfaces 51a, 52a of the movable die 52, the two processed circuit materials 41a are held by the pins 53 so that the circuit conductors 14 face each other. Then, the resin injection hole 5 provided in the fixed mold 51
From 1c, molding resin is injected and filled between the fixed mold 51 and the movable mold 52. After the molding resin has cooled or hardened, the processed circuit material 41a is taken out, and the unnecessary edge frame conductor 13 is cut off to obtain a double-sided circuit board in which the circuit conductors 14 are embedded on both surfaces of the resin molded body.

If the processed circuit material 41a is used,
A thick circuit conductor for large current was embedded in the insulating substrate, and a thin circuit conductor for small current was formed on the surface of the insulating substrate.
It is also possible to fabricate a composite circuit board having a large current circuit and a small current circuit. FIG. 6 is an explanatory view of a method of manufacturing a composite circuit board by using the processed circuit material 41a by hot pressing. That is, the two processed circuit materials 41a are arranged with the circuit conductor 14 on the outside, and an adhesive layer 61 such as a prepreg.
Are arranged so as to face each other. Also, the circuit material 41a
A copper foil 62 whose one surface 62a is roughened is also laminated on the outside of the via an adhesive layer 61. Next, the whole is integrated by heating and pressurizing with the hot press 63, and then the copper foil 62 is pattern-etched, and the unnecessary edge frame conductor 13 is cut off. In this case, the adhesive layers 61 are formed on both surfaces of the circuit material 41a.
Thus, the processed circuit material 41a can be laminated without limiting its front and back surfaces.

(Embodiment 2) FIG. 7 shows a circuit material molded by the method of this embodiment. This circuit material is
As shown in FIG. 3, the small protrusion 50 is provided between the protrusions 31b.
It is formed by using a fixed die 31 formed so as to connect to each other. The height of the small protrusion 50 is about half that of the convex portion 31b. In the circuit material of FIG. 7, shallow grooves 42b formed by the small protrusions 50 are formed so as to connect the recesses 42a. In this circuit material, as shown in FIG. 9, the circuit material is provided with a fixed mold 71 and a movable mold 7 having a flat cavity surface.
When the resin is injected while sandwiched between the two, the resin is filled in the recesses 42a through the shallow grooves 42b, so that there is an advantage that a circuit material having a flat surface can be obtained by injection or casting.

In the present embodiment, the convex portion 31b on the inner surface of the cavity of the molding die 30 is provided on the surface of the fixed die 31, but if the circuit conductor 11 can be fixed, the convex portion 31b.
b may be provided on the surface of the movable die 32. In addition, the convex portion 31
The shape of the circuit conductor 1 is such that the portion of the circuit conductor 11 having the smallest conductor width is not sandwiched between the convex portions 31b.
They may be arranged at intervals narrower than the minimum conductor width of 1, and the height from the inner surface of the cavity may be uniform, and the molding resin may be detachable from the mold, and may have a pin shape or a hemispherical shape.
Here, if the gap between the convex portions 31b is sufficiently narrowed,
One molding die 30 can be commonly used for many circuit conductor 11 patterns.

[0017]

As described above, according to the present invention, since the molding die having the projections or grooves as described above is used,
There is an excellent effect that it is possible to manufacture a circuit material that can flow a large current economically and without being limited by the thickness of the conductor by using the molding die in common.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a circuit material manufactured by a method for manufacturing a circuit material according to the present invention.

FIG. 2 is a plan view of a circuit conductor which constitutes the circuit material of the above embodiment.

FIG. 3 is an explanatory diagram of a step of resin-molding the circuit material of the above-described embodiment. is there.

4A and 4B are a plan view and a cross-sectional view taken along the line AA of the circuit material in a state in which a conductor portion of the circuit material of the above embodiment is electrically separated.

FIG. 5 is an explanatory diagram of a process of manufacturing a double-sided circuit board using the circuit material of the above-described embodiment.

FIG. 6 is an explanatory diagram of a process of manufacturing a composite circuit board using the circuit material of the above embodiment.

FIG. 7 is a perspective view showing another embodiment of the circuit material.

FIG. 8 is a cross-sectional view showing a molding step of the circuit material of FIG.

9 is a cross-sectional view showing a step of performing a second molding using the circuit material of FIG.

[Explanation of symbols]

 11 conductor 13 edge frame conductor 13a, 14a bridge 14 circuit conductor 20 cavity 20a, 51c injection hole 20b void 30, 50 molding die 31, 51, 71 fixed die 31a groove 31b convex portion 31c resin injection portion vicinity 32, 52, 72 Mobile type 41 Circuit material 41a Processed circuit material 42 Molding resin 42a Recess 42b Shallow groove 42c Convex ridge 43, 44 Through hole 50 Small ridge 51a, 52a Inner surface 53 Pin 61 Adhesive layer 62 Copper foil 62a Surface 63 Hot press

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29K 105: 22 B29L 31:34

Claims (2)

[Claims] 1. A plurality of molds having the same height when a conductor is set in a mold and then a resin is injected into the mold to produce a circuit material in which the mold resin and the conductor are integrated. A method for manufacturing a circuit material, wherein a convex part is used on at least one of the surfaces sandwiching the conductor regardless of the pattern of the conductor. 2. When a conductor is set in a molding die and then resin is injected into the mold to produce a circuit material in which the molding resin and the conductor are integrated, at least a surface sandwiching the conductor is used as the molding die. A method of manufacturing a circuit material, characterized in that a molding die having a groove crossing a conductor on one side and communicating with a resin injection portion is used.