JPH088419B2 - Printed wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a printed wiring board, for example, two layers on one side,
It is suitable for application to a multilayer printed wiring board having four layers on both sides.

[Outline of Invention]

The present invention is a printed wiring board configured to form a plurality of wiring pattern layers using a conductive paste on one or both surfaces of a copper clad laminate, forming a signal layer using the innermost copper foil, By forming the power supply and / or ground layer on the outer wiring pattern layer made of conductive paste,
A multilayer printed wiring board applicable to a wiring board for high-speed signal processing can be easily realized.

[Conventional technology]

Conventionally, in this type of printed wiring board, a multilayer printed wiring board is used so that electronic components can be mounted at high density.

That is, as shown in FIG. 2, in the multilayer printed wiring board 1, a double-sided copper-clad laminate 4A in which copper foils 3A and 3B are stretched on the upper and lower surfaces of a substrate 2 made of glass epoxy, for example.
On the upper and lower copper foils 3A and 3B, a wiring pattern layer (hereinafter referred to as a power supply layer 3AX and a ground layer 3BX, respectively) including a predetermined power supply line and a ground line is formed by etching.

Further, on the surface of the power supply layer 3AX and the ground layer 3BX, for example, the base material 2 side of the single-sided copper-clad laminate 4B formed by sticking the copper foils 3C and 3D to the one surface of the base material 2 made of glass epoxy has an adhesive or the like. They are laminated by hot pressing so as to be in contact with the power supply layer 3AX or the ground layer 3BX, respectively.

Thus, a wiring pattern consisting of a connection pattern of electronic parts formed by etching on the copper foils 3C, 3D of the single-sided copper-clad laminate 4B through the through-holes 6 perforated at predetermined positions and provided with the copper plating film 5 Layer (hereinafter signal this 3C
X, 3DX) and / or power layer 3AX, ground layer 3BX
4 layers 3AX, 3BX, 3C by electrical connection between
The multilayer printed wiring board 1 made of X and 3DX is configured.

[Problems to be solved by the invention]

However, in the four-layer printed wiring board 1 having such a configuration, for example, the single-sided copper-clad laminate 4B is heat-pressed on the surface of the double-sided copper-clad laminate 4A on which the wiring pattern layers of the power supply layer 3AX and the ground layer 3BX are formed by etching. Since the layers are laminated and pressure-bonded by the process, the manufacturing process cannot be complicated.

In addition to this, in order to manufacture a multilayer printed wiring board having four or more layers, it is necessary to accurately align the copper clad laminates, which further complicates the manufacturing process. .

In order to solve this problem, for example, after forming a power supply layer and / or a ground layer by etching on the single-sided copper-clad laminate 4B,
On the surface of the power supply layer and / or the ground layer, an insulating layer made of a resin material is used to form an insulating layer by screen printing on a portion other than the via hole portion connecting the layers, and further, for example, a copper paste or the like is formed on the surface. There has been proposed a method for manufacturing a multilayer printed wiring board in which a signal layer including a via hole portion is formed using a conductive paste.

However, even in this way, the wiring pattern formed by using the copper paste has a conductor resistance per unit area that is about 10 to 100 times higher than that of the wiring pattern formed by the copper foil.
For this reason, the wiring board used particularly for high-speed signal processing still has a problem in practical use.

The present invention has been made in consideration of the above points, and can solve the problems of the conventional multilayer printed wiring board all at once, can be manufactured by a simple process, and can be applied to a wiring board for high-speed signal processing. It is intended to propose a wiring board.

[Means for solving problems]

In order to solve such a problem, in the present invention, in a printed wiring board 10 configured to form a plurality of wiring pattern layers using the conductive paste 12 on one side or both sides of the copper clad laminate 4B, the copper clad laminate The signal layer 3X is formed by using the copper foil 3 on the surface of the plate 4B, and the power supply and / or ground layer 12X is formed by using a plurality of wiring pattern layers.

[Action]

By using the plurality of wiring pattern layers formed of the conductive paste 12 as the power supply and / or the ground layer 12X, the resistance value of the conductive paste 12 can be ignored,
Moreover, by using the copper foil 3 having a much lower electric resistance than the conductive paste 12 as the signal layer 3X, the multilayer printed circuit board 10 having a simple structure applicable to the wiring board for high-speed signal processing can be obtained. Can be realized.

〔Example〕

 An embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 2 are denoted by the same reference numerals, 10 indicates a multilayer printed wiring board having two layers on one side as a whole, and a copper foil 3 is attached to the surface of a base material 2 such as glass epoxy. A connection pattern of a desired electronic component 7 is drawn by etching on the single-sided copper-clad laminate 4B thus formed, whereby a desired signal layer 3X is formed.

In addition to this, on the surface of the signal layer 3X, in a portion other than the via hole portion 13 for connecting between layers, using an insulating paste 11 made of a resin material, a desired insulating pattern is drawn by screen printing, thus A desired insulating layer 11X is formed. Further, on the surface of the insulating layer 11X, a wiring pattern of a power source and an earth line is drawn by screen printing using a conductive paste made of, for example, a copper paste 12, and thus the power source and the earth layer 12X are formed.

Here, the signal layer 3X and the power supply / ground layer 12X with the insulating layer 11X sandwiched therebetween are filled with the copper paste 12 in the via hole portion 13 at the time of printing the power supply / ground layer 12X. The wiring pattern layers are electrically connected to each other.

In the case of this embodiment, the power and ground layer 12X is drawn in a thick film pattern, and further, the pattern width itself and the pattern width of the signal layer 3X are drawn in a width sufficiently wide, so that the copper paste 12 The conductor resistance of is practically negligible.

Further, the power supply and ground layer 12X is covered with an overcoat 14 made of an insulating material such as resin, whereby it is possible to prevent problems such as short-circuiting of the wiring pattern due to adhesion of moisture or dust. There is.

Further, in practice, in the multilayer printed wiring board 10, the electronic component 7 is mounted by soldering on the signal layer 3X which is not covered by the insulating layer 11X, the power supply and the ground layer 12X. The components 7 can be mounted with high density.

According to the above structure, the signal layer 3X is formed by etching the copper foil 3 on the copper-clad laminate 4B and drawing a desired wiring pattern for connecting the electronic component 7, and also on the signal layer 3X. The copper paste 12 is screen-printed on the insulating layer 11X to form a wiring pattern of desired power lines and ground lines to form the power source and ground layer 12X. It is possible to realize a multilayer printed wiring board 10 that can be mounted in and can be applied to a wiring board for high-speed signal processing.

Further, according to the above-described embodiment, the insulating layer 11X, the power supply and the ground layer 12X are formed by screen printing on the copper clad laminate 4B, so that the multilayer printed wiring board 10 is formed.
It is not necessary to carry out a hot pressing step in manufacturing, and the multilayer printed wiring board 10 can be manufactured by a simple process.

In the above-mentioned examples, as the copper-clad laminate, one having a base material made of glass epoxy was used, but the present invention is not limited to this, for example, a base material made of paper phenol, etc.
Even if a copper clad laminate having another structure is used, the same effect as that of the above-described embodiment can be obtained.

Further, in the above-mentioned embodiment, one embodiment using the copper paste as the conductive paste was shown, but the present invention is not limited to this, and the above-mentioned embodiment may be used even if another conductive paste such as a silver paste is used. The same effect as can be obtained.

Further, in the above-mentioned embodiment, one embodiment is shown in which the power supply line and the ground line are formed in the same layer, but this is provided in another layer via an insulating layer to form a multilayer printed wiring board having three layers on one side. By doing so, the same effect as that of the above-described embodiment can be obtained.

Furthermore, the present invention provides a multi-layered structure having 4 or 6 layers on both sides by forming a signal layer on both sides of a copper clad laminate and forming a power supply and / or ground line by using a conductive paste on each signal layer. It can be widely applied to a multilayer printed wiring board such as a printed wiring board having a plurality of layers on one side or both sides.

〔The invention's effect〕

As described above, according to the present invention, in a printed wiring board configured to form a plurality of wiring pattern layers using a conductive paste on one side or both sides of a copper clad laminate, a signal is provided on the innermost copper foil. By forming a layer and a power supply and / or a ground layer on a wiring pattern layer made of a conductive paste, the resistance value of the conductive paste can be ignored, and thus a multilayer printed circuit applicable to a wiring board for high-speed signal processing. The wiring board can be realized by a simple manufacturing process.

[Brief description of drawings]

FIG. 1 is a schematic line sectional view showing an embodiment of the present invention, and FIG. 2 is a schematic line sectional view showing a conventional multilayer printed wiring board. 1, 10 ... Multilayer printed wiring board, 2 ... Base material, 3 ...
Copper foil, 4 ... Copper clad laminate, 5 ... Copper plating film, 6 ... Through hole, 7 ... Electronic component, 11 ... Insulating paste, 12
…… Copper paste, 13 …… Byer hole, 14 …… Overcoat.

Claims (1)

[Claims] 1. A printed wiring board in which a conductive paste is used to form a plurality of wiring pattern layers on one surface or both surfaces of a copper-clad laminate, wherein the copper foil on the surface of the copper-clad laminate is used. A printed wiring board, wherein a signal layer is formed and a power source and / or an earth layer is formed using the plurality of wiring pattern layers.