JP4850356B2 - Interlayer connection structure and manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated wiring board formed by laminating a conductor layer and an interlayer insulating layer. More specifically, the present invention relates to an interlayer connection structure for electrically connecting conductor layers in a laminated wiring board and a manufacturing method thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a multilayer wiring board, an interlayer connection structure is provided everywhere to make a conduction point between upper and lower conductor layers by opening a hole in an interlayer insulating layer. This is what is called a via hole or a through hole. In such an interlayer connection structure, the hole formed in the interlayer insulating layer is usually plated and conduction is made up and down by the plating layer, or the hole is filled with a conductive filler and the upper and lower sides are filled by the filler. I have continuity.
[0003]
[Problems to be solved by the invention]
However, the conventional laminated wiring board described above has a problem that the conductivity between the upper and lower sides is insufficient. This is because when the upper and lower continuity is taken by the plating layer, the cross-sectional area of the conductive portion is regulated by the thickness of the plating layer. Further, when the upper and lower continuity is taken by the conductive filler, the conductivity of the filler is not so high. This is because a conductive filler is obtained by dispersing a powder of metal or the like in a resin. Because of this low electrical conductivity, it was difficult to use in places where a large current flows like the power system, regardless of the signal system. It is conceivable to fill the entire hole with plating to ensure conductivity, but this is not very productive.
[0004]
The present invention has been made to solve the problems of the conventional interlayer connection structure described above. That is, the problem is to provide an interlayer connection structure that achieves both sufficient conductivity and productivity, together with its manufacturing method.
[0005]
[Means for Solving the Problems]
In order to solve this problem, the interlayer connection structure of the present invention includes a hardened insulating layer, a conductive pin that penetrates the insulating layer and is cut outside thereof , and both ends project from the insulating layer, and the insulating layer. A core plate having an uncured adhesive resin layer that coats both sides of the substrate, and two wiring boards that are disposed on both sides of the core plate and have a conductor pattern on at least the surface on the core plate side, By pressing the core board between the two wiring boards, the conductor patterns of the two wiring boards face each other with the core board in between, and conduction between the conductor patterns of the two wiring boards through the pins of the core board Is taken. For this reason, unlike the conduction by the plating layer or filler, both the cross-sectional area and the conductivity of the conductive portion can be sufficiently secured.
[0006]
In the method for manufacturing an interlayer connection structure according to the present invention, a conductive pin is driven into the first surface of the cured insulating layer, the tip of the pin protrudes from the second surface of the insulating layer, and the pin is insulated at both ends. Cutting the outer side of the first surface of the insulating layer so as to protrude from the layer, and coating the both surfaces of the insulating layer with uncured insulating resin, and a conductor on at least one surface Two wiring boards having patterns are arranged on both sides of the core board so that the surface having the conductor pattern is on the core board side, and by pressing them, the conductor patterns of the two wiring boards are And a step of producing a laminated wiring board facing each other with the core board interposed therebetween and establishing conduction between the conductor patterns of the two wiring boards through the pins of the core board. Thereby, the interlayer connection structure in which the conductor patterns of the other wiring boards on both sides of the insulating base material are connected via the pins penetrating the insulating layer is manufactured.
[0007]
Here, when the pin is driven into the insulating layer, the pin is preferably heated. This is because if the pin is heated, it can be easily driven into the insulating layer. In addition, there is an advantage that the insulating layer is cured by the heat of the pin and the pin is fixed to the insulating layer. Therefore, when the insulating layer is a general thermosetting resin, the heating temperature of the pin is preferably about 120 to 170 ° C. Note that another wiring board and overlapping by pressing at the time of pressing pressure, good about 392N / cm ² higher than 294 N / cm ² generally used in conventional press of this kind. This is to ensure conduction with the conductor pattern at both ends of the pin.
[0009]
In the present invention, a constant thickness can be maintained by using a hardened insulating layer as compared to the case of using an uncured insulating layer. Therefore, the stability of the external dimensions after pressing can be ensured. In addition, the gap between the layers caused by using a cured resin can be filled by coating a cured insulating layer with an uncured insulating resin and heat-curing it simultaneously with pressing.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings.
[0011]
[First form]
In the first embodiment, a wiring board is manufactured by the procedure shown in FIG. The main ones used in this embodiment are a metal pin 1, a feeding mechanism 3 for driving the pin 1, a prepreg 7 to be a core insulating layer, and a double-sided wiring board 10 separately manufactured by a general manufacturing method. Can be mentioned.
[0012]
The pin 1 is a copper wire having a diameter of about 0.3 mm. The tip is cut by a mold pair 13 as shown in FIG. 2 and has a sharp shape. Each of the mold pairs 13 is formed by opposing a semiconical dent on the opposite surface from the front and back sides. The feeding mechanism 3 is a mechanism that gradually feeds the pin 1 while holding it like a feeding pencil. Further, the feeding mechanism 3 has a built-in heater so that the pin 1 can be heated to about 160 ° C. Or the mechanism which cut | disconnects the pin 1 like the mold pair 13 of FIG. 2 may be integrated.
[0013]
First, as shown in “drive-in” in FIG. 1, the pin 1 is driven into the prepreg 7 using the feeding mechanism 3. That is, the pin 1 is pushed into the prepreg 7 so that the tip of the pin 1 protrudes from the back side (lower side in FIG. 1) of the prepreg 7. The driving is performed by heating the pin 1 to about 120 to 170 ° C. This is because when the temperature of the pin 1 is high, the prepreg 7 is easily penetrated. Further, since the epoxy component of the prepreg 7 is cured by the heat of the pin 1, the pin 1 is fixed to the prepreg 7. Then, the pin 1 is cut on the front side of the prepreg 7 (upper side in FIG. 1).
[0014]
As a result, as shown by “penetration PP” in FIG. 1, the pin 1 penetrates the prepreg 7 and both ends of the pin 1 protrude from the front and back of the prepreg 7. In the “through PP”, a plurality of pins 1 are driven into the prepreg 7. The driving position of each pin 1 is a position where an interlayer connection structure is formed in the core layer of the wiring board to be manufactured. Hereinafter, this state is referred to as a core plate 8. In this state, the protruding portions at both ends of the pin 1 may be plated with gold or solder by electroless plating or the like.
[0015]
Then, as shown in “combination” in FIG. 1, two separately produced double-sided wiring boards 10, 10 are aligned and arranged on the front and back of the core board 8. When this is pressed, a four-layer wiring board 11 is completed as shown in "Press" in FIG. The press pressure during pressing is good about 392N / cm ² higher than 294 N / cm ² generally used in conventional press of this kind. This is because both ends of the pin are crushed and securely adhered to the conductor pattern of the double-sided wiring board 10. In the four-layer wiring board 11, the inner layers are electrically connected by the pins 1. That is, each pin 1 forms an interlayer connection structure between inner layers.
[0016]
The double-sided wiring board 10 often has its own interlayer connection structure at a position corresponding to the driving position of the pin 1 of the core board 8. In this case, as shown in FIG. 3, the inside may be filled with a filler 12 and may have a structure having lid platings 13 and 13, and as shown on the left side of FIG. There may be no through hole. In the latter case, however, the holes are filled with the filler 12 after pressing, as shown on the right side of FIG.
[0017]
In the four-layer wiring board 11 manufactured in this way, the interlayer connection between the inner layers is taken by the pins 1. The pin 1 is formed from a copper wire as described above. For this reason, the cross-sectional area of the conductive part between the front and back sides is remarkably wide compared to the interlayer connection using only the plating layer on the wall surface of the hole. In addition, the conductivity of the conductive part is remarkably high compared to the interlayer connection in which the hole is filled with the conductive filler. In addition, the productivity is much higher than the interlayer connection by filling all holes with plating. Compared with the interlayer connection using the plating layer on the wall of the hole, the productivity is high because it does not require complicated processes such as drilling and plating. Thus, according to the present embodiment, an interlayer connection structure that achieves both sufficient conductivity and productivity and a manufacturing method thereof are realized.
[0018]
Of course, an insulating layer or a conductor layer may be further built up on the front and back of the four-layer wiring board 11 to form a multilayer. Alternatively, a plurality of four-layer wiring boards 11 may be manufactured and laminated by interposing an insulating film.
[0019]
As described above in detail, in this embodiment, the pin 1 is driven into the prepreg 7 and the pin 1 is cut so that both ends protrude from the prepreg 7, and this core board 8 is combined with the other double-sided wiring board 10. Press. Thereby, the interlayer connection structure between the inner layers is formed by the pins 1. Therefore, the four-layer wiring board 11 having an interlayer connection structure in which the conductivity of the conductive portion is extremely high can be manufactured with high productivity.
[0020]
[Second form]
In the second embodiment, a wiring board is manufactured by the procedure shown in FIG. The main ones used in this embodiment are a metal pin 1, a feeding mechanism for driving the pin 1, a hardened sheet 14 such as a core material to be a core insulating layer, and both surfaces separately manufactured by a general manufacturing method. The wiring board 10 etc. are mentioned. The material of the cured sheet 14 is a cured thermosetting resin. The pin 1 and the feeding mechanism 3 are the same as those used in the first embodiment.
[0021]
First, as shown in “drive-in” in FIG. 5, the pin 1 is driven into the cured sheet 14 using the feeding mechanism 3. That is, the pin 1 is pushed into the cured sheet 14 so that the tip of the pin 1 protrudes from the back side (lower side in FIG. 5) of the cured sheet 14. Then, the pin 1 is cut on the front side of the cured sheet 14 (upper side in FIG. 5).
[0022]
As a result, as shown by “penetration” in FIG. 5, the pin 1 penetrates the cured sheet 14 and the both ends of the pin 1 protrude from the front and back of the cured sheet 14. In “penetration”, a plurality of pins 1 are driven into the cured sheet 14. The driving position of each pin 1 is a position where an interlayer connection structure is formed in the core layer of the wiring board to be manufactured. Hereinafter, this state is referred to as a core plate 15. In this state, the protruding portions at both ends of the pin 1 may be plated with gold or solder by electroless plating or the like.
[0023]
Next, as shown in “Coating” in FIG. 5, both surfaces of the core plate 15 are coated with an uncured thermosetting resin 16. Specifically, a liquid resin may be applied, a film may be attached, or a prepreg may be used. Hereinafter, this state is referred to as a coated core plate 17.
[0024]
Then, as shown in “combination” in FIG. 5, two separately produced double-sided wiring boards 10, 10 are aligned and arranged on the front and back of the coated core board 17. When this is pressed while being heated, a four-layer wiring board 18 is completed as shown in “Press” in FIG. The uncured resin 16 filling the gap between the two layers is cured by the heat at this time. The press pressure during pressing is good about 392N / cm ² higher than 294 N / cm ² generally used in conventional press of this kind. This is because both ends of the pin are crushed and securely adhered to the conductor pattern of the double-sided wiring board 10. In the four-layer wiring board 11, the inner layers are electrically connected by the pins 1. That is, each pin 1 forms an interlayer connection structure between inner layers.
[0025]
In the four-layer wiring board 18 manufactured in this way, the interlayer connection between the inner layers is taken by the pin 1 formed from a copper wire. For this reason, the cross-sectional area of the conductive part between the front and back is wide, and the conductivity of the conductive part is high. In addition, productivity is high compared to interlayer connection by filling all holes with plating. Thus, according to the present embodiment, an interlayer connection structure that achieves both sufficient conductivity and productivity and a manufacturing method thereof are realized.
[0026]
Further, in the four-layer wiring board 18, the pins 1 are driven into the cured resin. Therefore, compared with what uses uncured resin like a 1st form, fixed thickness can be ensured in the shape after a press. Further, in order to fill a gap between the inner layers generated by using a cured resin, it is filled with an uncured thermosetting resin. As a result, an interlayer connection structure and a manufacturing method therefor have been realized in which sufficient electrical conductivity and productivity are achieved while ensuring dimensional stability. Needless to say, a plurality of four-layer wiring boards 18 may be manufactured and laminated by interposing an insulating film.
[0027]
As described above in detail, in the present embodiment, the pin 1 is driven into the cured sheet 14 and the pin 1 is cut so that both ends protrude from the cured sheet 14. Then, the cured sheet 14 is coated with an uncured resin 16 to produce a coated core plate 17. The coated core plate 17 is pressed while being heated in combination with the other double-sided wiring board 10, and the uncured resin 16 is cured. Thereby, the interlayer connection structure between the inner layers is formed by the pins 1. Therefore, the four-layer wiring board 18 having an interlayer connection structure in which the conductivity of the conductive portion is extremely high can be manufactured with high productivity. Further, a pin is driven into the cured resin, and the gap between the inner layers is filled with the uncured resin 16 to cure the resin. Therefore, the four-layer wiring board 18 having an interlayer connection structure with a stable outer shape can be manufactured.
[0028]
Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the present embodiment, the prepreg 7 is used as the core insulating layer. However, the present invention is not limited to this, and any other insulating film having adhesiveness and a certain level of handling strength can be used. Some pins 1 can be used with other conductive materials other than copper wires.
[0029]
【The invention's effect】
As is apparent from the above description, according to the present invention, an interlayer connection structure having both sufficient conductivity and productivity is provided along with its manufacturing method.
[Brief description of the drawings]
FIG. 1 is a diagram showing a manufacturing procedure of a wiring board according to an embodiment.
FIG. 2 is a view showing an example of a mold for cutting a pin.
FIG. 3 is an enlarged view showing a contact portion between a pin and an outer layer interlayer connection structure;
FIG. 4 is an enlarged view showing a contact portion between a pin and an interlayer connection structure of an outer layer.
FIG. 5 is a diagram showing a manufacturing procedure of a wiring board coated with an insulating layer according to the embodiment.
[Explanation of symbols]
1 pin 3 feeding mechanism 7 prepreg 10 double-sided wiring board 13 mold pair 14 cured sheet 16 uncured resin

Claims (2)

A hardened insulating layer; a conductive pin that penetrates the insulating layer and is cut at the outside thereof , and has both ends protruding from the insulating layer; and an uncured adhesive resin layer that coats both surfaces of the insulating layer A core plate,
Two wiring boards each having a conductor pattern on at least one of the core board-side surfaces and disposed on both surfaces of the core board;
By pressing the core board between the two wiring boards, the conductor patterns of the two wiring boards are opposed to each other with the core board in between, and the two wirings are passed through the pins of the core board. An interlayer connection structure characterized in that conduction between conductor patterns of a plate is taken. A conductive pin is driven into the first surface of the cured insulating layer, the tip of the pin protrudes from the second surface of the insulating layer, and the pins are in a state where both ends protrude from the insulating layer. Cutting the outside of the first surface of the insulating layer, and coating the both surfaces of the insulating layer with an uncured insulating resin;
Two wiring boards having a conductor pattern on at least one surface are respectively arranged on both surfaces of the core plate so that the surface having the conductor pattern is on the core plate side, and these are pressed, thereby Producing a laminated wiring board in which conductive patterns of two wiring boards are opposed to each other with the core board sandwiched therebetween, and conducts between the conductive patterns of the two wiring boards through the pins of the core board;
A method for manufacturing an interlayer connection structure, comprising:

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