JP2551223B2 - Organic resin multilayer wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organic resin multilayer wiring board, and more particularly to a multilayer wiring board used in electronic equipment.

Conventional technology Conventionally, in the polyimide resin multilayer wiring board, the second
As shown in the figure, the power supply layer 12 and the ground layers 16a, 16a are provided on the ceramic (or glass ceramic) multilayer wiring board 11.
b, or the signal wiring layers 17a and 17b and the power / signal transfer layer 18
The conductor wiring layers and the polyimide resin insulating layers 15a to 15f were alternately laminated.

The conductor wiring layers are electrically connected by via holes 14, and the electric component mounting layer 10 is provided on the uppermost layer on the ceramic multilayer wiring substrate 11.

In general polyimide resin, which is said to be a good material for electronic materials, the dielectric constant that affects the signal propagation speed of the wiring of the multilayer wiring board is about 3.4 to 3.8. In order to realize the above, a polyimide having a lower dielectric constant will be used. Currently, polyimide resins with a dielectric constant of about 2.9 to 3.0 are also available.

As a multilayer wiring board using benzocyclobutene resin (hereinafter referred to as BCB resin), a multilayer wiring board having four wiring layers and four insulating layers and a total insulating film thickness of about 30 microns was developed. ing.

In such a conventional polyimide resin multilayer wiring board,
I use polyimide with a dielectric constant of about 3.4 to 3.8,
If the dielectric constant of polyimide is further lowered to realize a high propagation speed, the film strength of the polyimide will be reduced, and there is a problem that it is difficult to put it into practical use.

When BCB resin is used, BCB resin has an induction rate of 2.6.
It has lower electrical properties than polyimide and is electrically superior, but its coefficient of thermal expansion is 4.0 × 10 ^{-5, which is} similar to that of polyimide resin.
Although it is (1 / ° C), the elongation rate is as low as 2.2%, so B
When the multilayer wiring board is made to have a high multilayer structure only with CB resin, the stress increases as it goes up, and cracks occur at the corners of the wiring where the stress of the conductor wiring concentrates, or the stress of the insulating film itself increases. There is a problem that the strength of the insulating film is exceeded and finally the insulating layer is cracked.

The object of the present invention is to eliminate the above-mentioned problems of the conventional one, and it is possible to realize a high signal propagation speed without causing a crack in a corner portion of a wiring or an insulating layer. An object is to provide an organic resin multilayer wiring board.

Configuration of the invention The organic resin multilayer wiring board according to the present invention is an organic resin multilayer wiring board in which conductor wiring layers and organic resin insulating layers are alternately laminated, and a signal layer and a ground layer among the conductor wiring layers. It is characterized in that the insulating layer between them is made of benzocyclobutene resin, and the other insulating layers are made of polyimide resin.

Embodiment Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. In the figure, a ceramic (or glass ceramic) multilayer wiring board 1 is coated with a conductor such as copper or gold to a thickness of 10 by plating.
The power supply layer 2 is formed with a line width of 25 microns.

On this ceramic multilayer wiring board 1, a via hole 9a made of a polyimide resin that can be cured at 400 ° C or lower.
And a polyimide resin insulating layer 5a having a thickness of 20 μm is formed.

Here, the reason for using a polyimide having a curing temperature of 400 ° C. or lower is that the weight reduction starting temperature of the benzocyclobutene resin (hereinafter referred to as BCB resin) is 430 ° C. Therefore, it is necessary to set the curing temperature to 430 ° C. or lower. Because there is.

The ground layer 3a and the signal wiring layer 4a are formed on the polyimide resin insulating layer 5a by a plating method, and the via hole 9b is formed between the ground layer 3a and the signal wiring layer 4a with the BCB resin. The BCB resin insulating layer 6a that it has is formed with a thickness of 20 microns.

On the signal wiring layer 4a, a polyimide resin insulating layer 5b of a type that can be cured at 400 ° C. or lower and has a via hole 9c is formed with a thickness of 20 μm.

A signal wiring layer 4b is formed on the polyimide resin insulating layer 5b by a plating method, a BCB resin insulating layer 6b having a via hole 9d is formed on the signal wiring layer 4b with a thickness of 20 μm, and a ground layer is formed thereon. 3b is formed by the plating method.

Furthermore, a polyimide resin insulating layer 5c having a via hole 9e is formed on the ground layer 3b with a thickness of 20 microns,
The power supply / signal transfer layer 7 is formed on the polyimide resin insulation layer 5c by a plating method, and the polyimide resin insulation layer 5d having a via hole 9f is formed on the power supply / signal transfer layer 7 with a thickness of 20 μm. The electric component mounting layer 8 is formed by plating.

Here, in this embodiment, since BCB resin is used only between the ground layers 3a and 3b and the signal wiring layers 4a and 4b, the conventional BB resin is used.
As in the case of increasing the number of layers in a multilayer wiring board using only CB resin, cracks will not occur at the corners of the wiring or the insulating layer.

Further, since the signal wiring delay is determined by the dielectric constant of the insulating layer between the ground layers 3a, 3b and the signal wiring layers 4a, 4b, by using a BCB resin having a low dielectric constant in this portion, the wiring board material It is possible to improve the electric characteristics as described above, and it is possible to realize a high signal propagation speed.

In this way, the ground layers 3a and 3b, the signal wiring layers 4a and 4b, or the conductor wiring layers such as the power supply / signal transfer layer 7 and the electric component mounting layer 8 and the polyimide resin insulating layers 5a to 5d are alternately laminated. In the resin multilayer wiring board, the BCB resin insulation layers 6a, 6b are provided between the ground layers 3a, 3b and the signal wiring layers 4a, 4b.
To form a dielectric constant of 3.4 to 3.8.
The dielectric constant of the insulating layer between the ground layers 3a, 3b and the signal wiring layers 4a, 4b is reduced to 2.6, compared to a general polyimide resin insulating layer, so that a high signal propagation speed can be realized. You can

Moreover, since the insulating layer of BCB resin is used only between the ground layers 3a and 3b and the signal wiring layers 4a and 4b, the corner portions of the wiring can be formed as in the case where only the BCB resin is used to increase the number of layers of the multilayer wiring board. It is possible to prevent the occurrence of cracks in the insulating layer.

Therefore, a high signal propagation speed can be realized without generating a crack in the corner portion of the wiring or the insulating layer.

EFFECTS OF THE INVENTION As described above, according to the present invention, the insulating layer between the signal layer and the ground layer of the conductor wiring layers alternately laminated on the organic resin multilayer wiring board is made of benzocyclobutene resin. By doing so, there is an effect that a high signal propagation speed can be realized without generating a crack in the corner portion of the wiring or the insulating layer.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. Explanation of symbols for main parts 1 …… Ceramic multilayer wiring board 3a, 3b …… Ground layer 4a, 4b …… Signal wiring layer 5a-5b …… Polyimide resin insulation layer 6a, 6b …… Benzocyclobutene resin insulation layer

Claims (1)

(57) [Claims] 1. An organic resin multilayer wiring board in which conductor wiring layers and insulating layers of organic resin are alternately laminated, wherein the insulating layer between the signal layer and the ground layer of the conductor wiring layers is made of benzo. An organic resin multilayer wiring board comprising a cyclobutene resin and the other insulating layer made of a polyimide resin.