JPH05267392A - Multilayer interconnection board - Google Patents

Abstract

PURPOSE:To extend the break life of an electrode by preventing the occurance of a thermal stress and a thermal strain at the time of the solder flow, in a thin-film multilayer interconnection board wherein a semiconductor chip is connected through solder balls. CONSTITUTION:Electrodes for mounting a semiconductor ball are located symmetrically about the center of a thin-film multilayer interconnection board 3 or about the center line. These electrodes include effective electrodes (white circle 4) which are electrically connected to a semiconductor chip (requiring connection) and uneffective (dummy) electrodes (black circle 7). The effective electrodes include isolated electrodes 6 (having no effective electrode at adjacent lattice points). All these electrodes are symmetrized (about a point or about a line) and are electrically connected to a wiring on the rear face of the substrate via a through hole and therefore electrical isolation of the electrodes can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board such as a thin film multilayer wiring board for connecting semiconductor chips via solder balls, and more particularly to a solder ball and electrodes for mounting solder balls. The present invention relates to a multilayer wiring board having a long life.

[0002]

2. Description of the Related Art FIG. 4 shows a thin film multilayer wiring board 3 in which a semiconductor chip 1 formed by a conventional technology is connected via a solder ball 2. There are electrodes 4 that require electrical connection and electrodes 5 that do not require electrical function. The electrode 5 is generated for standardization of the solder ball mounting electrode arrangement of the semiconductor chip. Conventionally, a solder ball mounting electrode is not formed at a position corresponding to the electrode 5 of the semiconductor chip on the thin film multilayer wiring substrate, but a solder ball mounting electrode is provided only at a position corresponding to the electrode 4 of the semiconductor chip. Is forming. The film structure of the solder mounting electrode is described in Japanese Patent Laid-Open No. 3-120853, but no consideration is given to the electrode arrangement.

[0003]

In FIG. 4, since the semiconductor chip 1 and the thin film multilayer wiring board 3 are made of different substrate materials, they have different thermal expansion coefficients. For this reason, thermal stress and thermal strain are generated in the solder ball and the solder ball mounting electrode during heating during reflow for mounting the solder ball and various heating thereafter. However, in the thin film multilayer wiring board formed by the above-mentioned conventional technique, no consideration is given to symmetry in the arrangement of the solder ball mounting electrodes in the board. Due to the above situation, in the conventional technology, the solder ball of the thin-film multilayer wiring board is
Among the mounting electrodes, a large thermal strain occurs only in a specific electrode, shortening the life in actual use.

One of the causes of such a problem is that
There is no regularity in the arrangement of electrodes for mounting solder balls on a thin-film multilayer wiring board, so-called isolated electrodes in which electrodes are not arranged around them, and electrodes asymmetrically arranged in the chip with respect to the center point of the chip It is considered that the cause is that a large thermal strain is generated in the specific electrode due to the generation.

Therefore, the first object of the present invention is to overcome the above-mentioned problems of the prior art, and prevent the generation of thermal stress and thermal strain by the electrode arrangement without these isolated electrodes or asymmetric electrode arrangement. Another object of the present invention is to provide a long-life multilayer wiring board by preventing fatigue fracture.

The above-mentioned problems occur in two ways:
It is considered that this is partly due to the electrically isolated (floating) electrodes. That is, when the above-mentioned electrode arrangement is realized, a so-called dummy electrode that does not need to have an electrical function is generated in the solder ball mounting electrode of the thin film multilayer wiring board. When forming the dummy electrode, if the solder ball mounting electrode is formed only on the uppermost layer of the thin film multilayer wiring board and is in an electrically isolated state, a thin film forming process, for example, plating film formation or sputtering film formation A potential difference occurs between the electrically isolated dummy electrode and the regular electrode electrically connected to the thin-film multilayer wiring board. It is considered that the cause of the peeling of the film and the low adhesive strength of the film due to the difference in the film stress and the film stress.

Therefore, a second object of the present invention is to provide a multilayer wiring board in which the electrically isolated (floating) electrodes as described above are not generated.

[0008]

In order to achieve the above first object, the present invention provides a multilayer wiring board for connecting a semiconductor chip via a semiconductor ball, wherein a solder ball mounting electrode is provided with respect to the center of the board. Arrange in point symmetry, line symmetry, or point symmetry and line symmetry.

Further, among these electrodes, at least one or more electrodes are arranged at a lattice point adjacent to the electrode which needs to be supplied or taken out of an electric function from the semiconductor chip. In order to achieve the second object, among the electrodes,
Electrodes (dummy electrodes) that do not require supply or extraction of electrical functions to the semiconductor chip are electrically connected to the back side of the substrate through through holes or conductor wiring (thin film multilayer wiring).

[0010]

The operation based on the above configuration will be described.

According to the present invention, the electrodes for mounting the solder balls are arranged symmetrically and there is no electrode isolated from the adjacent grid point, so that a large thermal strain does not occur in the specific electrode and the solder balls and The breaking life of the solder ball mounting electrode can be greatly extended. Further, since the dummy electrode is connected to the back side of the substrate through the through hole or the conductor wiring, the solder ball mounting electrode of the thin film multilayer wiring substrate is an electrode which does not require supply or extraction of an electrical function to the semiconductor chip ( Dummy electrodes) and electrodes that require them are formed uniformly (film formation) without variations in film characteristics
As a result, a highly reliable electrode film can be formed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a solder ball according to an embodiment of the present invention.
Layout plan of thin film multilayer wiring board having electrodes for mounting
FIG. 2 is a sectional view of FIG. In FIGS. 1 and 2, among the solder ball mounting electrodes 6, the circles filled with black are the electrodes 7 (dummy electrodes) that do not require the supply or extraction of electrical functions to the semiconductor chip. The simple white circles are the electrodes 4 for which the semiconductor chip needs to be supplied or taken out with an electrical function. Further, in FIG. 1, the part with no teeth, which does not have any of the white circles 4, 6 and the black circle 7 at the lattice points, is the part where no corresponding electrode exists on the semiconductor chip side. (On the other hand, the portion of the dummy electrode 7 is a portion where the corresponding dummy electrode exists also on the semiconductor chip side).

Looking only at the electrode 4, there are several isolated electrodes 6 (without any adjacent electrodes around). The electrode 7 is arranged at the adjacent lattice point of the electrode 6 so as to apparently avoid isolation. Further, the entire arrangement in the thin-film multilayer wiring board 3 is arranged so as to be point-symmetric with respect to the center point P of the board 3.

Further, as shown in the sectional view, the electrodes 4 and 6 are provided.
As a matter of course, all the electrodes including the electrode 7 were electrically connected to the back surface of the substrate by the through holes and the wiring film in the thin film multilayer wiring.

The film structure of the electrodes 4, 6, 7 etc. for mounting the solder balls is constructed as shown in FIG. FIG. 3 is a detailed cross-sectional view in which a part of FIG. 2 is enlarged for explaining the method of manufacturing the thin film multilayer substrate 3 of FIGS. Although it is simplified in FIG. 2, the one in FIG. 3 is multi-layered to form the one in FIG.
The upper part of the electrodes 4 and 7 of FIG.
It is shown as 13. In FIG. 3, a through hole formed on the polyimide-based organic interlayer insulating film on the aluminum or copper film of the thin film internal wiring 8 or the inorganic interlayer insulating film 9 such as silicon oxide is bonded to the insulating film as the adhesive layer 10. Formed of copper or an alloy of copper and nickel as a solder diffusion preventing layer 11 by sputtering or the like on a chromium film or the like having good properties,
After that, patterning is performed by normal photo etching.
Gold or the like is formed thereon as a wetting layer 13 with solder by a plating method. At this time, nickel or the like may be formed as a further layer between the copper and the alloy of copper and nickel and the gold or the like as the solder diffusion preventing layer 12 by plating. If there is an electrically isolated electrode during this plating, the above-mentioned potential difference occurs and film peeling occurs.

In the electrodes shown in FIGS. 1, 2 and 3, there are variations in film characteristics in the above chromium film, spattering film formation of copper or an alloy of copper and nickel, and nickel film formation and gold film formation. It did not occur, and no film peeling occurred even when the solder ball was mounted.

In the above embodiment, the electrodes are arranged symmetrically with respect to the points, but the objects can be similarly achieved by arranging the electrodes symmetrically with respect to the front and rear or the left and right, or symmetrically with respect to the points and the line.

According to this embodiment, there is a feature that it can be easily carried out only by changing a photomask for manufacturing a thin film multilayer wiring board.

[0020]

As described above, according to the present invention,
Since the electrodes for mounting the solder balls of the multilayer wiring board are symmetrically arranged and there is no isolated electrode, there is an effect that the occurrence of thermal strain can be prevented and the life can be greatly improved.

Further, since the dummy electrode is electrically connected to the back side of the substrate through the through hole or the thin film multi-layer wiring, the electrically floating electrode is eliminated, and the film peeling can be prevented.

[Brief description of drawings]

FIG. 1 is a plan layout view of a thin film multilayer wiring board having solder ball mounting electrodes according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cross section of FIG.

FIG. 3 is a diagram showing a film configuration of a solder ball mounting electrode.

FIG. 4 is a diagram showing a thin-film multilayer wiring board in which semiconductor chips are connected via solder poles by a conventional technique.

[Explanation of symbols]

 1 Semiconductor Chip 2 Solder Ball 3 Thin Film Multilayer Wiring Board 4 Solder Ball Mounting Electrode 5 Solder Ball Mounting Electrode 6 Solder Ball Mounting Electrode (Isolated Electrode) 7 Solder Ball Mounting Electrode ( Dummy electrode) 8 Thin film internal wiring 9 Interlayer insulating film 10 Adhesive layer 11 Solder diffusion prevention layer 12 Solder diffusion prevention plating layer 13 Solder wetting layer

Claims (3)

[Claims] 1. In a multilayer wiring board for connecting a semiconductor chip via a solder ball, electrodes for mounting a solder ball are arranged in point symmetry, line symmetry, or point symmetry and line symmetry with respect to the center of the board. Multilayer wiring board. 2. Among the electrodes for mounting the solder ball, an electrode which does not require supply or extraction of an electric function to a semiconductor chip is electrically connected to the back side of the substrate through a through hole or a conductor wiring. The device is connected to
The multilayer wiring board described. 3. At least one electrode is arranged at a grid point adjacent to an electrode of the solder ball mounting electrode that needs to be supplied or taken out of an electrical function from a semiconductor chip. The multilayer wiring board according to claim 1 or 2.