JPH04152696A - Organic resin multilayer wiring board - Google Patents

Abstract

PURPOSE:To prevent cracks from occurring to the corners of a wiring and an insulating layer and to enable signals to propagate at a high speed by a method wherein conductor wiring layers and insulating layers are alternately laminated on an organic resin multilayer wiring board and an insulating layer interposed between the signal layer and the ground layer out of the laminated conductor wiring layers is formed of benzocyclobutane resin. CONSTITUTION:Conductor wiring layers such as ground layers 3a and 3b, signal wiring layers 4a and 4b, a power supply signal transfer layer 7, or an electric component mounting layer 8 and polyimide resin insulating layers 5a-5d are alternately laminated to form a polyimide resin multilayer wiring board where BCB resin insulating layers 6a and 6b are formed between the ground layers 3a and 3b and the signal wiring layers 4a and 4b. The insulating layers between the ground layers 3a and 3b and the signal wiring layers 4a and 4b are lower in permittivity than the polyimide resin insulating layer normal in permittivity, so that signals can be made to propagate at a high speed. As the BCB resin insulating layers 6a and 6b are formed only between the ground layers 3a and 3b and the signal wiring layers 4a and 4b, cracks can be prevented from occurring to the corners of a wiring or an insulating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an organic resin multilayer wiring board, and particularly to a multilayer wiring board used in electronic equipment.

Conventional technology Conventionally, in polyimide resin multilayer wiring boards, ceramic (or glass ceramic)
A power layer 12 and a ground layer 16a are formed on the multilayer wiring board 11.
, 16b, or signal wiring layers 1.7a, 17b
The conductor wiring layer of the power/signal transfer layer 18 and the polyimide resin insulating layers 15a to 15f were alternately laminated.

The conductive wiring layers were electrically connected by via holes 14, and an electrical component mounting layer 10 was provided in the uppermost layer on the ceramic multilayer wiring board 11.

General polyimide resin, which is said to be a good material as an electronic material, has a dielectric constant of about 3.4 to 3.8, which affects the propagation speed of signals in the wiring of multilayer wiring boards. In order to achieve higher propagation speeds, polyimide with an even lower dielectric constant must be used. Currently, polyimide resins with a dielectric constant of about 2.9 to 3.0 are also available.

Additionally, as a multilayer wiring board using benzocyclobutene resin (hereinafter referred to as BCB resin), a multilayer wiring board has been developed that consists of four wiring layers and four insulation layers, and has an insulation film thickness of approximately 30 microns. has been done.

Such conventional polyimide resin multilayer wiring boards use polyimide with a dielectric constant of about 3.4 to 3.8, but in order to achieve high propagation speeds, it is necessary to lower the dielectric constant of polyimide further. However, there is a problem in that the strength of the polyimide film decreases, making it difficult to put it into practical use.

In addition, when using BCB resin, BCB resin has a dielectric constant of 2.6, which is lower than polyimide, and has excellent electrical properties, but a coefficient of thermal expansion of 4.6, which is about the same as that of polyimide resin.
Although Ox 10-5 (1/”C), the elongation rate is 2
．． Since the stress is as low as 2%, if a multilayer wiring board is made with only BCB resin, the stress will increase as you go to the upper layer, and cracks may occur at the corners of the wiring where the stress of the conductor wiring is concentrated. Alternatively, there is a problem in that the stress of the insulating film itself exceeds the film strength of the insulating film, eventually causing cracks in the insulating layer.

Purpose of the Invention The present invention has been made to eliminate the problems of the conventional ones as described above, and can realize a high signal propagation speed without causing cracks in the corners of the wiring or the insulating layer. The purpose is to provide an organic resin multilayer wiring board.

Structure 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. The insulating layer between them is made of benzocyclobutene resin, and the other insulating layer is 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 plated with a conductor such as copper or gold to a thickness of 10! The power supply layer 2 is formed with a line width of 25° and a line width of 25°.

On this ceramic multilayer wiring board 1, a via hole 9 is made of a polyimide resin that can be cured at 400°C or less.
The polyimide resin insulating layer 5a having a is 20! It is formed with a chrome thickness.

Here, the reason for using polyimide with a curing temperature of 400°C or lower is that the temperature at which benzocyclobutene resin (hereinafter referred to as BCB resin) starts to lose weight is 430°C, so the curing temperature needs to be 430°C or lower. This is because there is.

A ground layer 3a and a signal wiring layer 4a are formed on this polyimide resin insulating layer 5a by a plating method.
BCB between the ground layer 3a and the signal wiring layer 4a
BCB resin insulating layer 6 made of resin and having via holes 9b
A is formed with a thickness of 20 microns.

On the signal wiring layer 4a, there is a polyimide resin insulating layer 5b made of a type of polyimide resin that can be cured at 400° C. or lower and having via holes 9C. It is formed with a thickness of RJ.

A signal wiring layer 4b is formed on the polyimide resin insulation layer 5b by a plating method, and a BCB resin insulation layer 6b having a thickness of 204 mm and having via holes 9d is formed on the signal wiring layer 4b. Layer 3b is formed by a plating method.

Further, on the ground layer 3b, a polyimide resin insulating layer 5c having a via hole 9e is formed with a thickness of 20 μm, and on the polyimide resin insulating layer 5c, a power/signal transfer layer 7 is formed by a plating method.・Polyimide resin insulating layer 5 having via hole 9f on signal transfer layer 7
d is 20! The electrical component mounting layer 8 is formed thereon by a plating method.

Here, in this embodiment, the BCB resin is used for the ground layers 3a, 3.
Since it is used only between the BCB resin and the signal wiring layers 4a and 4b, cracks do not occur at the corners of the wiring or in the insulation layer, as in the case of increasing the number of layers in a multilayer wiring board using only conventional BCB resin. There's nothing left to do.

Furthermore, 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 BCB resin, which has a low dielectric constant, in this part, the electrical characteristics as a wiring board material can be improved, and a high signal propagation speed can be realized.

In this way, the ground layers 3a, 3b, the signal wiring layer 4a,
4b, or conductive wiring layers such as the power/signal transfer layer 7 and the electrical component mounting layer 8 and polyimide resin insulation layers 5a to 5d.
In a polyimide resin multilayer wiring board in which layers are alternately laminated, the ground layer 3a.

By forming the BCB resin insulating layers 6a and 6b between the signal wiring layers 3b and the signal wiring layers 4g and 4b, the dielectric constant is about 3.4 to 3.8 compared to a general polyimide resin insulating layer. The ground layers 3a, 3b and the signal wiring layer 4a,
Since the dielectric constant of the insulating layer between the insulating layer and the insulating layer 4b is lowered to 2.6, a high signal propagation speed can be achieved.

Further, an insulating layer of BCB resin is used as a ground layer 3a.

3b and the signal wiring layers 4a and 4b, it prevents cracks from occurring at the corners of the wiring or in the insulating layer, as would be the case when building a multilayer wiring board with high multilayers using only BCB resin. I can do it.

Therefore, a high signal propagation speed can be achieved without cracking the corners of the wiring or the insulating layer.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the insulating layer between the signal layer and the ground layer among 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 cracking the corners of the wiring or the insulating layer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. Explanation of symbols of main parts 1...Ceramic multilayer wiring board 3a, 3b...
...Ground layers 4a, 4b...Signal wiring layer

Claims (1)

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