JPH06334347A - Multilayer interconnection substrate - Google Patents

Abstract

PURPOSE:To provide the title multilayer interconnection substrate capable of setting up and controlling the characteristics impedance of a signal wiring layer as well as composing at low cost. CONSTITUTION:The title multilayered wiring substrate is provided with a ceramic laminated layer wiring parts 3 comprising a laminated layer 3a, a power supply wiring layer 3b and a signal wiring layer 3c as well as a thin film wiring layer 4 comprising plural signal wiring layers 4a including a gland wiring layer 4b integrally formed on said ceramic laminated layer wiring parts 3. In such a constitution, said multilayer interconnection wiring substrate is composed of the gland wiring layer 4b of the thin film wiring part 4 to be positioned on the upper layer than the topmost signal wiring layer 4a' as well as said plural signal wiring layers 4a, 4a' laminatedly arranged between the grand wiring layers 4b of the ceramic laminated layer wiring part 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer wiring board suitable for a high-density and high-performance system having a high-density mounting structure, and more particularly to a multi-layer wiring board suitable for a multi-chip module (MCM).

[0002]

2. Description of the Related Art A high-speed system whose clock frequency exceeds 50 MHz cannot be realized only by developing high-speed LSI elements. That is, high-speed LSI elements are mounted at high density,
A wiring board that minimizes the mounting delay between LSI elements is required. Further, such a wiring board is generally formed into a multi-layer wiring structure by using so-called thin film technology in order to realize high-density fine wiring and a required characteristic impedance. FIG. 3 is a cross-sectional view showing a structure of a multilayer wiring board configured for such an application.
It is composed of a so-called ceramic-based laminated wiring portion 1 and a thin film wiring portion 2. That is, the ground wiring layer 1a, the power supply wiring layer 1b, and the signal wiring layer 1c are laminated via the ceramic insulating layer 1d, and are connected to the brazing pads 1e arranged on one main surface through the laminated region. The ceramic-based laminated wiring section 1 including the through-hole connection section 1h electrically connecting the output pin 1f and the connection section 1g arranged on the other main surface is used as the base substrate. A plurality of signal wiring layers 2a and a pad 2b including a signal wiring layer electrically connected to the connection portion 1g by a via hole are formed on the ceramic-based laminated wiring portion 1 forming the base substrate by using a resin system such as a polyimide resin. The thin film wiring part 2 is laminated and integrally formed via the insulating layer 2c.

[0003]

In the multilayer wiring board having the above structure, the characteristic impedance of the signal wiring layer 2a of the thin film wiring portion 2 can be controlled by the distance from the ground wiring layer 1a of the ceramic laminated wiring portion 1. But each conductor layer 1a, 1
In reality, the characteristic impedance cannot be set as designed due to the variation in the thickness of the ceramic insulating layer 1d between b and 1c. Further, when this type of multilayer wiring board is operated at a high speed of, for example, 50 MHz or more, it is necessary to control the characteristic impedance of the signal wiring layer 2a of the thin film wiring portion 2 to a constant value. A large distance from the ground wiring layer 1a is set. That is,
The thickness of the ceramic insulating layer 1d (interlayer insulation) must be increased, but there is a limit to the thickness of the ceramic insulating layer 1d in terms of compactness and multilayer wiring density. Therefore, since the characteristic impedance of the signal wiring layer 2a cannot be sufficiently controlled, it can be said that the signal wiring layer 2a must be put to practical use in a state where the electrical (circuit) characteristic remains poor.

The present invention has been made in consideration of the above circumstances, and sets the characteristic impedance of the signal wiring layer to a required value.
An object of the present invention is to provide a multilayer wiring board that can be controlled and can be constructed at low cost.

[0005]

A multilayer wiring board according to the present invention comprises a ceramic-based laminated wiring section formed by laminating a ground wiring layer, a power supply wiring layer, and a signal wiring layer, and a ceramic-based laminated wiring section on the ceramic-based laminated wiring section. A multi-layer wiring board comprising a thin film wiring section composed of a plurality of signal wiring layers including a ground wiring layer formed integrally, wherein the ground wiring layer of the thin film wiring section is located above the signal wiring layer. In addition, the plurality of signal wiring layers are arranged in a laminated manner between the plurality of signal wiring layers and the ground wiring layer of the ceramic laminated wiring portion.

[0006]

In the multilayer wiring board according to the present invention, the signal wiring layer is sandwiched between the ground wiring layer of the ceramic laminated wiring portion and the ground wiring layer of the thin film wiring portion. That is, since the signal wiring layer has a strip structure sandwiched between two upper and lower ground wiring layers, the characteristic impedance of the signal wiring layer can be easily controlled, and for example, high-speed LSI elements can be densely arranged. If implemented,
It becomes possible to function as a multilayer wiring board that minimizes the mounting delay between LSI elements. In other words, it is possible to provide low-priced, high-performance MCM.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 which is a cross-sectional view showing an example of the essential part configuration of a multilayer wiring board according to the present invention, and a partial cutaway of the essential part of the ceramic type laminated wiring part of the multilayer wiring board according to the present invention. An embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows an MCM (multi-chip module).
This is a standard multilayer wiring board used for the above-mentioned configuration, and is composed of a ceramic-based laminated wiring section 3 and a thin-film wiring section 4.
That is, the ground wiring layer 3a, the power supply wiring layer 3b, and the signal wiring layer 3c are stacked via the ceramic insulating layer 3d, and the input for connecting the brazing pad 3e arranged on one main surface through the stacked area. The ceramic-based laminated wiring portion 3 including the output pin 3f and the connecting portion 3g is used as the base substrate. In addition, in this ceramic-based laminated wiring part 3, 3h
Is a seal ring for joining the open end faces of the sealing cap, and the ceramic-based laminated wiring portion 3 is a conventional one that is used in the manufacture of a multilayer laminated wiring board using this type of ceramic as an insulating layer. Manufactured by means.

A plurality of signal wiring layers 4a including a signal wiring layer electrically connected to the connecting portion 3g by a via hole, a ground wiring layer 4b, and a pad 4c are provided on the ceramic-based laminated wiring portion 3 forming the base substrate. For example, a thin film wiring part 4 is laminated and integrally formed through a resin-based insulating layer 4d such as a polyimide resin.
Is adopted. Here, the thin film wiring part 4
Is a conventional means for forming a thin film wiring portion (layer) that multi-layers the signal wiring layer 4a via the resin-based insulating layer 4d, in other words, in the thin film process, as an upper layer of the uppermost signal wiring layer 4a '. After the ground wiring layer 4b is provided via the resin-based insulating layer 4d, a part of the manufacturing process may be changed so as to form the connection pad 4c or the like.

In the multilayer wiring board according to the present invention, as described above, the input / output pin 3f is not led out to the one main surface side of the ceramic type laminated wiring section 3 in which the thin film wiring section 4 is formed,
Similar to the case shown in FIG. 3, the input / output pin 3f may be led out to another main surface (back surface). Further, in the ceramic laminated wiring section 3, the signal wiring layer 3c may not be formed as an inner layer, but only the ground wiring layer 3a and the power supply wiring layer 3b may be formed as inner layers. Then, in the case of the structure in which only the ground wiring layer 3a and the power supply wiring layer 3b are made inner layers, since the connection portion 3g and the input / output pin 3f are directly connected in a penetrating manner, each connection portion The 3g will only function as connection pads independently of each other. Therefore, in this case, the area (region) occupied by the connecting portion 3g reduces the obstacle between the ground wiring layer 3a in the ceramic-based laminated wiring portion 3 and the signal wiring layer 4a in the thin film wiring portion 4, and reduces the characteristic impedance. In order to facilitate control, it is desirable to set it to about 20% or less of the main surface of the thin film wiring portion 4.

Further, in the structure of the thin film wiring portion 4, the insulating layer 4d may be made of another resin other than the polyimide resin or an inorganic material such as SiO ₂ , and the ground wiring layers 3a and 4b and the power source. Wiring layer 3b, signal wiring wiring 3c,
The parts 4a, 4a ', the connecting parts 3e, 3g, the connecting pad 4c, etc. are formed of, for example, Al, Cu or the like.

[0012]

As described above, the multilayer wiring board according to the present invention has a structure in which the signal wiring layer is sandwiched between the ground wiring layer of the ceramic laminated wiring portion and the ground wiring layer of the thin film wiring portion. That is, since the signal wiring layer has a strip structure sandwiched between the upper and lower ground wiring layers, the characteristic impedance of the signal wiring layer can be easily controlled. For example, when high-speed LSI elements are mounted in high density, it can function as a multi-layer wiring board that minimizes the mounting delay between LSI elements.
Will be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a main part of a multilayer wiring board according to the present invention.

FIG. 2 is a perspective view showing a configuration example of a main part of a ceramic-based laminated wiring portion forming a part of a multilayer wiring board according to the present invention.

FIG. 3 is a cross-sectional view showing a main part structure of a conventional multilayer wiring board.

[Explanation of symbols]

1, 3 ... Ceramic-based laminated wiring section 1a, 3a, 4b ... Ground wiring layer 1b, 3b ... Power supply wiring layer 1c, 2a, 3c, 4
a, 4a '... Signal wiring layer 1d, 3d ... Ceramic insulating layer
1e, 3e ... Brazing pads 1f, 3f ... I / O pins
1g, 3g ... Connection part 1h ... Through hole connection part 2, 4 ... Thin film wiring part 2b,
4c… Pads 2c, 4d… Resin insulation layer 3h… Sealing ring

Claims (1)

[Claims] 1. A plurality of ceramic wiring layers including a ground wiring layer, a power wiring layer, and a signal wiring layer, and a plurality of ground wiring layers integrally formed on the ceramic wiring layer. A multilayer wiring board comprising a thin film wiring portion formed of a signal wiring layer, wherein the ground wiring layer of the thin film wiring portion is located above the signal wiring layer, and the plurality of signal wiring layers are ceramic-based laminated wiring. A multilayer wiring board characterized in that the multilayer wiring board is arranged in a laminated manner with a ground wiring layer of a part.