JP2822811B2 - Wiring structure of multilayer wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a multilayer wiring board,
In particular, it relates to the structure of a wiring pattern.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a conventional multilayer wiring board having a wiring structure. As shown in FIG. 3, a wiring connecting the through hole 31 and the through hole 32 is an X wiring 33.
But there was only one structure. Similarly, through hole 3
4 and the through hole 35, the Y wiring 36 is 1
It was a book only structure.

However, for example, a power supply wiring through which a large current flows or a high-speed signal wiring may require a lower wiring resistance than the above-described general wiring pattern structure. In addition, a conductor material such as tungsten having a high wiring resistance must be used for the wiring of the alumina ceramic substrate, and there is a case where it is desired to lower the resistance structurally.

In order to solve this problem, it is necessary to increase the cross-sectional area by increasing the width and / or thickness of the wiring,
Alternatively, a conventional general idea is to use a conductor made of a material having a small specific resistance.

[0005]

In general, it is often difficult in the manufacturing process to increase the thickness of the wiring to reduce the wiring resistance and to use a material having a small specific resistance.
There are limitations due to thickness restrictions and material choices.

On the other hand, when the wiring width is widened, the wiring gap is reduced accordingly, and the insulation reliability is reduced, or the wiring pitch for making the gap constant is increased, and the mounting density of mounted components is reduced. .

Changing the cross-sectional area of the wiring to reduce the wiring resistance has the above-mentioned problems.

It is an object of the present invention to provide a wiring structure of a multilayer wiring board having low resistance wiring.

[0009]

In order to achieve the above object, a wiring structure of a multilayer wiring board according to the present invention is a wiring structure of a multilayer wiring board having wiring connecting predetermined through holes, The wiring is configured as a multilayer structure of two or more adjacent layers , and the wiring of each layer is formed.
Have the same wiring pattern.

[0010]

[0011] The wiring of each layer of the multilayer structure is connected through a through hole.

[0012]

Since the wiring connecting the through holes has at least a two-layer structure, the resistance value of the wiring can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a multilayer wiring ceramic substrate according to a first embodiment of the present invention. First, the substrate manufacturing process will be described step by step.

First, an organic solvent such as a dispersant and a plasticizer is added to a mixed powder of an alumina powder and a binder for solidification, mixed and stirred sufficiently to form a slurry.
Cellulose (Methylcellulose,
Ethyl cellulose), polyvinyl alcohol, acrylic, polyvinyl butyral, etc. are mainly used. As the dispersant, a nonionic surfactant is used, and as the plasticizer, dibutyl phthalate, dioctyl phthalate, glycerin, or the like is used.

Although there are several methods for producing a ceramic green sheet, a doctor blade method suitable for forming a thin sheet is used here. In this method, the slurry is cast by a gap between a knife called a doctor blade and a continuous film, and dried by hot air to form a green sheet on the film. In this method, the sheet thickness is about 0.5.
It is possible between 03 and 1 mm. In this embodiment, about 0.2
mm and the width of the casting was about 160 mm.
Cut this continuous sheet to the size of about 150mm □,
It is a square green sheet.

Next, through-hole holes are formed in the sheet at predetermined positions determined by a combination of a pin and a mold. The pore size is about 250 μm.

After the formation of the through-holes, a conductive paste is embedded in all the through-holes by a thick film printing method, and a predetermined signal wiring pattern on the sheet surface is formed. Tungsten (W) or molybdenum (Mo) having a high melting point is used as the printing paste material in consideration of the firing temperature of the ceramic. Wiring width and film thickness are 2
00 μm and 10 μm.

The conventional wiring has one layer in each of the X and Y directions. However, in this embodiment, each of the X and Y wirings has a two-layer structure as shown in FIG. 1 in order to reduce the resistance. That is, in order to connect the through hole 11 and the through hole 12, an X wiring 14 is additionally formed in addition to the normal X wiring 13.
Similarly, in order to connect the through hole 15 and the through hole 16, a Y wiring 18 is additionally formed in addition to the normal Y wiring 17. Thus, the XY wirings 13, 14, 17, 18
Are the same wiring pattern.

The ceramic green sheets printed in this manner are laminated so as not to be displaced in the laminating step. Here, the number of laminated sheets is 12 per substrate.

Thereafter, a plurality of sheets are integrally formed by a hot press method to form a laminate. The pressing conditions are a pressure of 150 kg / cm ² , a temperature of 100 ° C., and a time of about 1 hour. In this step, a green laminated substrate having a thickness of about 2 mm is completed. Finally, the green laminated substrate is debindered and fired at about 1500 ° C. to obtain the ceramic substrate 19.

The wiring resistance of the multi-layer substrate obtained in the above process is about 0.5 Ω / cm compared to about 0.8 Ω / cm of the conventional wiring structure.
The value was about half of 4Ω / cm.

(Embodiment 2) FIG. 2 is a sectional view showing Embodiment 2 of the present invention.

In the structure of FIG. 1, two wirings 13 and 14, 1
If one of the wires 7 and 18 is thinned or broken for some manufacturing reason, the resistance value becomes large.
In the present embodiment, in order to reduce the rise in resistance in the first embodiment, as shown in FIG.
4, 17 and 18 are connected through connection through holes 21.

In this embodiment, the interval between the connection through holes 21 is 1 mm. With such a structure, the reliability against thinning or disconnection of the wiring is improved.

[0026]

As described above, according to the present invention, since the wiring connecting between the through holes has a wiring structure of a plurality of layers, the wiring resistance can be reduced without increasing the wiring width, and therefore, the components can be reduced. There is no reduction in mounting density.

Furthermore, by connecting through a through hole in the middle of a plurality of layers of wiring, it is possible to improve the reliability against thinning or disconnection of the wiring.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Through hole 12 Through hole 13 X wiring 14 X wiring 15 Through hole 16 Through hole 17 Y wiring 18 Y wiring 19 Ceramic substrate 21 Connection through hole

Claims (2)

(57) [Claims] 1. A wiring structure of a multilayer wiring board having wiring connecting predetermined through holes to each other, wherein the wiring is configured as a multilayer structure having two or more adjacent layers , and Wiring is the same wiring pattern
A wiring structure of a multilayer wiring board, characterized by having: 2. The wiring structure of a multilayer wiring board according to claim 1, wherein the wiring of each layer of the multilayer structure is connected via a through hole.