JPH04328896A - Multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To enable a multilayer printed wiring board to be sharply enhanced in wiring density by a method wherein by a method wherein a power supply pattern and a ground pattern are formed into the teeth of a comb on the same plane alternately confronting each other, and the power supply pattern and the ground pattern are optionally connected to each other through blind through- holes. CONSTITUTION:An inner conductor is composed of a power supply pattern 13 and a ground pattern 14. The power supply pattern 13 and the ground pattern 14 are formed into the shape of the tooth of a comb on the same plane alternately confronting each other. Furthermore, an outer wiring conductor 11 and a electric wire pattern 13 and the outer wiring conductor 11 and the ground pattern 14 are connected to each other through blind through-holes 15. That is, through-holes are lessened in number as much as possible, and the power supply layer 13 and the ground layer 14 are easily connected with each other through the blind through-holes 15. By this setup, a thin board is protected against damage caused by drilling and free from curved holes, so that a multilayer printed wiring board high in wiring density can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board having a power supply layer and a ground layer, and more particularly to a multilayer printed wiring board with high density wiring.

0002

2. Description of the Related Art In recent years, as electrical equipment has become smaller and more sophisticated, demands for high-density wiring on printed wiring boards have been increasing. In order to satisfy this demand, efforts have been made to improve the wiring density by making the conductor patterns formed on printed wiring boards as fine as possible, so-called fine patterning. On the other hand, with multilayering, which achieves high-density wiring by multilayering conductor layers, it is possible to form even higher-density multilayer printed wiring boards by making electrical connections only between each layer through small-diameter conductive holes. Efforts have also been made to develop a high-density multilayer printed wiring board technology called blind through-hole.

Conventionally, printed wiring boards having blind through holes have been made into multilayer boards by laminating and pressing double-sided boards having through holes formed by drilling using prepreg as an insulating layer. Furthermore, since the blind through hole is drilled into a thin substrate as the outer layer substrate, it is possible to perform small diameter drilling without the risk of drill breakage or hole bending.

However, as shown in FIG. 4, the blind through hole 25 connects the outer layer wiring conductor 21 of the first layer, the inner layer power layer 23 of the second layer, the inner layer ground layer 24 of the third layer, and the outer layer wiring of the fourth layer. Although the conductor 21 can be connected, the first layer outer layer wiring conductor 21, the third layer inner layer ground layer 24, the second layer inner layer power supply layer 23 and the fourth layer outer layer wiring conductor 21 are connected through blind through holes 25. Since the connection cannot be made with a through hole 26, the connection had to be made with a through hole 26.

The through-hole 26 is a hole drilled through a multilayer printed wiring board.Drilling through a thick board at once causes the drill to break and bend, making it difficult to process small-diameter holes, and making large holes difficult. It was a through hole with a diameter. Therefore, restrictions on pattern design became large and high-density wiring could not be realized. In addition, in recent years, the number of terminals for power supply and grounding of electronic components has increased in order to stabilize the electrical characteristics, and through holes are used to connect the terminals to the inner power supply layer and inner layer ground layer of the multilayer printed wiring board. is increasing significantly. Therefore, the increase in the number of large-diameter through-holes has become a serious problem.

[0006]

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the number of through-holes as much as possible, and to connect the power supply layer and the ground layer using blind through-holes. It is an object of the present invention to provide a multilayer printed wiring board that can be easily formed, that is, can be drilled with a small diameter without fear of drill breakage or hole bending on a thin board, and can realize high-density wiring.

[0007]

[Means for Solving the Problems] The means taken by the present invention to achieve the above object are explained with reference numerals used in the embodiments. In the wiring 100, the power supply patterns 13 and the ground patterns 14 are alternately opposed to each other on the same plane of at least one layer of the inner layer conductor 12, and are formed in a comb-like shape, and the outer layer wiring conductor 11 is formed by blind through holes 15. and the power supply pattern 13, the outer layer wiring conductor 11, and the ground pattern 14 were connected, respectively.''

[0008]

[Operation] In the multilayer printed wiring board 100 of the present invention, since the power supply pattern 13 and the ground pattern 14 are formed on the same plane of at least one layer of the inner layer conductor 12, the outer layer wiring conductor 1
1 and the power supply pattern 13, and the outer layer wiring conductor 11 and the ground pattern 14 can be arbitrarily connected. Further, the power supply patterns 13 and the ground patterns 14 are formed in a comb-like shape so as to alternately face each other on the same plane. Therefore, the power supply pattern 13 and the ground pattern 14 are alternately formed in the shape of a comb so that it can be used as both the power supply pattern 13 and the ground pattern 14 within the area formed in the shape of a comb.

[0009]

[Embodiments] Examples embodying the present invention will be described below with reference to FIGS. 1 to 3. First, 4 shown in Figures 1 and 2
The manufacturing method of the embodiment of the multilayer printed wiring board 100 is as follows:
First, a copper foil to become the outer layer wiring conductor 11, a power supply pattern 13 and a ground pattern 14 to become the inner layer conductor 12, and a through hole to become the blind through hole 15 are formed on both sides of the board as a double-sided through hole board. At this time, the copper foil to become the outer layer wiring conductor 11 is not patterned at this stage because it is patterned after the through-holes 16 are formed in a later process. In addition, the power supply pattern 13 and the ground pattern 1 which are to become the inner layer conductor 12
4 are formed in the shape of comb blades so as to alternately face each other on the same plane as shown in FIG. Next, this board, the copper foil that will become the outer layer wiring conductor 11, and the inner layer conductor 12 formed in the same manner.
A double-sided through-hole board having a power supply pattern 13 and a ground pattern 14 to become a blind through-hole 15 and a through-hole to become a blind through-hole 15 are connected to
The power supply pattern 13 and the ground pattern 14 which are to be formed are placed on the inside, and are bonded together using a thermocompression press via the prepreg. Then, appropriate through-holes 16 are drilled, outer layer wiring conductors 11 are formed by etching, and 2
The two inner layer conductors 12 of the layer and the third layer are connected to the power supply pattern 1.
A multilayer printed wiring board 100 was obtained in which the ground patterns 3 and 14 were alternately opposed to form a comb-like shape.

In the case of the embodiments shown in FIGS. 1 and 2, the outer layer wiring conductor 11 of the first layer, the inner layer conductor 12 of the second layer, the inner layer conductor 12 of the third layer and the outer layer wiring conductor 11 of the fourth layer are connected. Since the connection can be made through the blind through hole 15, the diameter of the hole can be reduced because the blind through hole 15 can be formed in a thin substrate. Figure 1
In Examples 2 and 2, the thickness of the substrate was 0.2 mm, and the diameter of the blind through hole 15 was 0.3 mm.

In the embodiments shown in FIGS. 1 and 2, the inner layer conductor 12 formed in a comb-like shape with the power supply patterns 13 and the ground patterns 14 facing each other alternately is used as the second layer and the third layer. Therefore, the power supply and ground connections can be made between the first layer and the second layer, and the third layer and the fourth layer using the blind through holes 15, so that the number of through holes 16 can be minimized. Then, the power supply pattern 13 of the inner layer conductor 12
When the ground patterns 14 are formed uniformly in a comb-like pattern on the same plane so as to face each other alternately, warping of the board can be prevented, and the power supply patterns 1 of the inner layer conductor 12 can be prevented from warping.
When the ground patterns 3 and 14 are formed in a comb-like pattern on the same plane, facing each other at equal intervals, noise can be blocked by the capacitor effect.

Note that FIGS. 1 and 2 show a four-layer board in which power supply patterns 13 and ground patterns 14 are alternately opposed to each other and inner layer conductors 12 formed in a comb-like shape are used as two layers, the second and third layers. Although an example has been shown, the present invention is not limited thereto, and the present invention is a multilayer printed wiring board having three or more layers, and at least one of the inner layer conductors has a comb blade in which the power supply pattern 13 and the ground pattern 14 are alternately opposed to each other. It is sufficient if it is formed in a shape. Also, power supply pattern 13 and ground pattern 1
It is not necessary to form the conductors 4 at uniform density on the same plane as a whole, and the conductor width can be narrowed and wired at a high density in accordance with the degree of concentration of wiring around a concentration of electronic components. Furthermore, in the multilayer printed wiring board 100 having six or more layers,
An inner layer conductor 12 formed in a comb-like shape with power supply patterns 13 and ground patterns 14 facing each other alternately is connected to an outer layer wiring conductor 1.
It is desirable to provide it as an inner layer conductor immediately inside 1. This is to facilitate connection between the outer layer wiring conductor 11, the power supply pattern 13, and the ground pattern 14 through the blind through hole 15.

FIG. 3 is a plan view showing another embodiment, and the difference from FIGS. 1 and 2 is that the comb-shaped power supply patterns 13 and ground patterns 14 that are alternately opposed to each other are formed obliquely, and The main point is that it has a notch 17. In the embodiment shown in FIG. 3, the power supply patterns 13 and the ground patterns 14 are alternately opposed to each other in the shape of comb blades and are oblique, which has the effect of preventing the board from warping in the vertical and horizontal directions. Furthermore, since it has a notch 17 in which a wiring pattern can be formed, the degree of freedom in design can be increased.

[0014]

Effects of the Invention As detailed above, according to the present invention, the outer layer wiring conductor and the power supply pattern and ground pattern formed as the inner layer conductor can be arbitrarily connected by blind through holes, thereby dramatically increasing the wiring density. can be improved. In addition, if the power supply patterns and the ground patterns are alternately opposed and uniformly formed in a comb-like pattern on the same plane, this will cause the board to warp. When they are formed in a comb-like pattern facing each other on the same plane, they have the effect of blocking noise due to the capacitor effect, and therefore have a very large industrial effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a multilayer printed wiring board of the present invention.

FIG. 2 is a plan view of an inner layer conductor of the multilayer printed wiring board of the present invention.

FIG. 3 is a plan view of another example of the inner layer conductor of the multilayer printed wiring board of the present invention.

FIG. 4 is a cross-sectional view of a conventional multilayer printed wiring board.

[Explanation of symbols]

11 Outer layer wiring conductor 12 Inner layer conductor 13 Power supply pattern 14 Grounding pattern 15 Blind through hole 16 Through hole 17 Notch 100 Multilayer printed wiring board

Claims (1)

[Claims] 1. A multilayer printed wiring board having a power supply pattern and a ground pattern as inner layer conductors, wherein the power supply pattern and the ground pattern are arranged alternately facing each other on the same plane of at least one layer of the inner layer conductor to form a comb-like shape. 1. A multilayer printed wiring board, characterized in that the outer layer wiring conductor and the power supply pattern are connected to each other by blind through holes, and the outer layer wiring conductor and the ground pattern are connected to each other by blind through holes.