JPH0637450A - Multilayered thin-film printed-circuit board - Google Patents

Abstract

PURPOSE:To provide a multilayered thin-film printed-circuit board capable of reliable connection by forming I/O terminals, each having a non-buffering composite structure of different metal layers and being isolated electrically from the substrate surface. CONSTITUTION:A first interconnection layer 2a, and underlays 3a for I/O terminals 3 are provided on the surface of an insulating substrate 1. The layers 2a and 3a each include a refractory metal layer and an aluminum layer. The entire surface of the substrate, except part of the surface of the individual underlays, is covered with an insulating layer 2d. A protective layer is formed around the inner insulating layer 2d and the underlays 3a, and interconnection layers 2b and 2c and another inner insulating layer 2d are formed to provide a multilayered thin-film interconnection 2. The interconnection layers 2b and 2c are extended to connect the underlay 3a, and a contact layer 3c for an I/O terminal 3 is provided. The uppermost interconnection layer 2c is then covered with a protective insulating layer 2d'. In this manner a reliable, multilayered thin-film printed circuit board is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film multi-layer wiring board, and more particularly to a thin film multi-layer wiring board suitable for the construction of multichip modules and hybrid ICs.

[0002]

2. Description of the Related Art In recent years, electronic parts or electronic circuits have been miniaturized and increased in density (increased capacity). For example, packaged semiconductor devices are widely mounted and mounted on so-called printed circuit boards. Are known. But,
Since the conventional mounting means is limited in high density (large capacity), development of a multi-chip module etc. using a thin film multilayer wiring board which can be manufactured by thin film technology as a wiring board for mounting has been promoted. ing. In response to these trends, the current situation is that the development of thin film multilayer wiring boards is being actively promoted.

FIG. 3 and FIG. 4 are cross-sectional views showing the essential parts of different structural examples of such a thin-film multilayer wiring board. In the case of FIG. 3, a supporting board having an insulating layer on its surface is shown. The multilayer wiring portion 2 is formed and arranged on the surface of the predetermined area 1 and the uppermost wiring layer 2c of the multilayer wiring portion 2 is extended between the I / O terminal forming area surfaces to form the I / O terminal portion 3. On the other hand, in the case of FIG. 4, the first wiring layer (underlayer or bottom layer) 2a of the multilayer wiring part 2 and a plurality of layers are formed on the surface of the predetermined area of the supporting substrate 1 on which the insulating layer is provided. I / O terminal part 3
Underlying layer 3a is formed and arranged in the same process, and at the subsequent stage of forming the multilayer wiring part 2, that is, the wiring layer 2 of the second and subsequent layers.
b, 2c, for example, when the wiring layer 2c is formed of a metal material different from that of the first wiring layer 2a, it is electrically connected to the base layer 3a surface of the I / O terminal portion 3 by a via hole,
The underlying layer 3a immediately plays the role of the I / O terminal section 3. In FIGS. 3 and 4, 3d is the wiring layers 2a, 2b, 2c.
The interlayer insulating layer between 2 and 2d 'is a surface protective layer.

[0004]

However, in the case of the thin film multi-layer wiring board having the construction whose essential parts are shown in FIGS. 3 and 4, the following inconvenient problems are recognized. First, FIG.
In the configuration shown in FIG. 1, the first wiring layer 2a on the surface of the supporting substrate 1
The underlying wiring layer and the I / O terminal portion 3, which constitutes the above, and particularly the region where the I / O terminal portion 3 is to be formed is not protected at all, and the multilayer wiring portion 2 is formed. That is, the required wiring layers 2a, 2b,
In the process of sequentially forming 2c, etc., the insulating layer on the surface where the I / O terminal portion 3 is to be formed is removed or damaged during patterning by selective etching of the metal layer (film) or the interlayer insulating layer 2d. However, there is a problem that the insulation function is impaired. In particular, when a silicon plate having a surface oxide layer is used as the supporting substrate 1, there is a disadvantage that an electrical short circuit easily occurs between the I / O terminal portions 3 due to damage of the surface oxide layer.

Further, even in the configuration shown in FIG.
There is a problem similar to the case of the configuration. For example, the surface of the underlying layer 3a forming the I / O terminal portion 3 is damaged during the formation of the multi-layer wiring portion 2 to make an electrical connection with the outside. There is a problem that the strength cannot be obtained.

On the other hand, as shown in FIG. 5 which shows the structure of the main part, a part of the interlayer insulating layer 2d of the multilayer wiring part 2 is extended, and the I / O terminal part 3 or It is also known to form and arrange contact portions. However, in the case of this configuration, the insulating layer forming the underlayer generally acts as a buffering agent, and the mechanical fixing property of the I / O terminal portion 3 is poor, so that a reliable electrical connection to the outside is provided. There is a problem that can not be achieved. In particular, when the insulating layer forming the underlayer is made of an organic material such as polyimide resin, the force required for mechanical connection tends to be dispersed, so that the reliability of the connection is impaired.

The present invention has been made in view of the above points, and an object of the present invention is to provide a thin film multilayer wiring board which is highly reliable and can be electrically connected to the outside, and which is suitable for a structure such as a multichip module. .

[0008]

A thin film multilayer wiring board according to the present invention is a thin film multilayer wiring board in which a multilayer wiring section and an I / O terminal section for electrically connecting to the outside are formed on a main surface of a supporting substrate. In the wiring board, the I / O terminal portion is separated into a plurality of base layers made of the same metal as the metal forming the first wiring layer adjacent to the supporting substrate surface of the multilayer wiring portion, A terminal portion protective layer made of the same kind of insulator as the interlayer insulating layer between the first wiring layer and the second wiring layer, which covers the peripheral surface and the area surface where the wiring pattern does not exist, and the multilayer wiring portion. Of the second wiring layer and subsequent wiring layers, which is made of the same kind of metal as the wiring layer and is connected to the wiring layer, and the other end of which is connected to the exposed surface of the underlying layer. It is characterized by being made.

[0009]

According to the present invention, first, the base layer whose I / O terminal portion is made of the same metal as that of the first wiring layer can be formed simultaneously with the first wiring layer in the same process. On the other hand, not only the insulating property is surely maintained, but also the peripheral surface of the base layer and the area surface where the wiring pattern does not exist are covered with the insulating layer. Then, a contact layer is formed on the exposed surface of the underlayer having the above-described structure or form by extending from any of the wiring layers after the second wiring layer. In other words, each I / O terminal is configured in multiple layers with different kinds of metals and without buffering effect while ensuring the required electrical insulation from the surface of the support substrate, and has a good surface condition. As a result, it retains and demonstrates a highly reliable connection function for external power sources.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a cross-sectional view showing an example of the essential structure of a thin-film multilayer wiring board according to the present invention. The multilayer wiring part 3 formed and arranged integrally on the surface of the silicon substrate 1 with the film via the oxide film (insulating layer) is an oxide film on the surface of the other region of the silicon substrate 1 with the oxide film. It is an I / O terminal portion that is integrally formed and arranged via an (insulating layer) to electrically connect to the outside. And said
The I / O terminal portion 3 is divided into a plurality of base layers 3a made of a metal that constitutes the first wiring layer 2a adjacent to the surface of the supporting substrate 1 of the multilayer wiring portion 2, for example, a metal similar to Ti or Cr. An interlayer insulating layer between the first wiring layer 2a and the second wiring layer 2b, which covers at least a part of the peripheral portion of each of the base layers 3a and the area of the outer peripheral portion where the wiring pattern does not exist A terminal part protection layer 3b made of the same kind of insulator as 2d, and any wiring layer 2b after the second wiring layer 2b of the multilayer wiring part 2;
Metals that compose 2c ..., such as Ti-Cu-Ti composite system or
Wiring layers 2b and 2c made of the same metal as the Cr-Cu-Cr composite system
, And the other end is connected to the exposed surface of the corresponding underlying layer 3a.

The thin film multilayer wiring board according to the present invention can be easily manufactured by the following means. 2 (a) and 2 (e) are cross-sectional views schematically showing an example of a manufacturing embodiment. First, as the insulating support substrate (base substrate) 1, for example, a silicon substrate with an oxide film is prepared. Then, on the main surface of the insulating support substrate 1, as a first metal layer (underlayer), for example, by vapor deposition or sputtering, a Ti layer, a Cr layer, etc.
After sequentially depositing and forming the Al layer, for example, oxygen gas and
Patterning is performed by dry etching with CF ₄ or the like to form the first wiring layer 2a and the required number of base layers 3a of the I / O terminal portions 3 (FIG. 2 (a)). That is, the first wiring layer 2a and the underlying layer 3a of the I / O terminal portion 3 are composed of a composite layer of a high melting point metal layer and an Al layer (surface layer). Then, for example, a polyimide resin layer is deposited / formed as an interlayer insulating layer 2d on the surface of the first wiring layer 2a and the underlying layer 3a of the I / O terminal portion 3 (FIG. 2 (b)). In the formation of the interlayer insulating layer 2d, the peripheral portion and the region where the wiring pattern does not exist in the outer peripheral portion are also covered for protection so as to expose a part of the main surface of each base layer 3a. The interlayer insulating layer
After forming the protective layer around 2d and the underlying layer 3a, the second wiring layers 2b, 2c ... And the interlayer insulating layer 2d between these wiring layers 2b, 2c ... The thin film multilayer wiring part 2 is formed (FIGS. 2 (c) to 2 (e)). Here, the wiring layers 2b, 2c ... Are, for example, a composite having a structure in which a Cu layer is sandwiched by a Ti layer, or a composite having a structure in which a Cu layer is sandwiched by a Cr layer. The I / O terminal portion 3 is formed by being extended at any of the wiring layer forming steps and electrically connected to the exposed surface of the underlying layer 3a to form the I / O terminal portion 3, while the uppermost wiring layer (2c in the figure is formed). ) Protective insulating layer 2d '
By forming it, the thin film multilayer wiring board having the structure shown in FIG. 1 is obtained. In this structure, the surface of the protective insulating layer 2d 'can also be used for mounting and mounting electronic components.

The present invention is not limited to the above-mentioned examples, but the gist of the invention, in other words, the I / O terminal portion is provided with an underlayer of the same metal as that of the first wiring layer, and the peripheral edge of this underlayer is provided. Area and outside peripheral area where no wiring pattern is present is covered with an insulating material of the same kind as the interlayer insulating layer to provide a terminal portion protective layer, and any wiring layer after the second wiring layer is formed. To the extent that it extends to the metal wiring layer and connects to the exposed surface of the corresponding underlying layer to form a contact layer,
For example, I / O terminal parts may be scattered and installed in the peripheral part and the central part.

[0014]

As described above, in the thin film multilayer wiring board according to the present invention, first, the underlayer made of the same metal as the first wiring layer forming a part of the I / O terminal portion is Since it is formed simultaneously with the first wiring layer in the same process, not only does it surely maintain the insulating property with respect to the surface of the supporting substrate, but also the peripheral surface of the underlying layer and the area surface where the wiring pattern does not exist are the insulating layer. It is covered with. Then, in the form having the above-described structure or form, one of the wiring layers after the second wiring layer is extended to the exposed surface of the underlayer to form a contact layer. In other words, each I / O terminal is configured in multiple layers with different kinds of metals and without buffering effect while ensuring the required electrical insulation from the surface of the support substrate, and has a good surface condition. Because,
Maintains and demonstrates a highly reliable connection function for external power supplies.

[Brief description of drawings]

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

FIG. 2 schematically shows an example of a process of manufacturing a thin-film multilayer wiring board according to the present invention, in which (a) shows a state in which a first wiring layer and an I / O terminal portion base layer are formed. Cross section showing
18b) is a cross-sectional view showing a state in which a first interlayer insulating layer is formed, (c) is a cross-sectional view showing a state in which a second wiring layer is formed, and (d) is a second layer interlayer. FIG. 6E is a cross-sectional view showing a state in which an insulating layer is formed, and FIG. 6E is a cross-sectional view showing a state in which the uppermost wiring layer also serving as a contact layer is formed and a surface protective layer is further provided.

FIG. 3 is a cross-sectional view showing a configuration example of a main part of a conventional thin-film multilayer wiring board.

FIG. 4 is a cross-sectional view showing another configuration example of the main part of a conventional thin-film multilayer wiring board.

FIG. 5 is a cross-sectional view showing still another example of the main part configuration of a conventional thin-film multilayer wiring board.

[Explanation of symbols]

1 ... Insulating support substrate 2 ... Multilayer wiring part 2a ... Bottom wiring layer 2b ... Second wiring layer 2c ... Top wiring layer
2d ... interlayer insulation layer 2d '... surface protection layer 3 ... I / O terminal part 3a ... base layer 3b ... terminal protection layer
3c ... Contact layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 9355-4M H01L 23/12 Q

Claims (1)

[Claims] 1. A thin-film multilayer wiring board comprising a supporting board, a main surface of which a multilayer wiring section and an I / O terminal section for electrical connection with the outside are formed, wherein the I / O terminal section is a multilayer wiring section. A plurality of underlayers made of the same kind of metal as the first wiring layer adjacent to the supporting substrate surface, and a region surface where no wiring pattern exists in the peripheral portion and the outer peripheral portion of each of the underlying layers. A terminal portion protection layer made of an insulating material of the same kind as the interlayer insulating layer between the first wiring layer and the second wiring layer, and any wiring layer after the second wiring layer of the multilayer wiring portion. A thin-film multilayer wiring board comprising a contact layer made of the same kind of metal as the constituent metal and connected to the wiring layer, and the other end being connected to the exposed surface of the corresponding underlying layer.