JPS63208247A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To improve the step coverage of an upper wiring layer at a connecting hole for connecting a conductor film and the upper wiring layer and to connect the upper wiring layer and a lower wiring layer excellently, by providing a connecting hole for connecting the lower wiring layer and the conductor film and the hole for connecting the conductor film and the upper wiring layer so that the holes are shifted to each other. CONSTITUTION:A first wiring layer 3 such as an aluminum film is covered with an interlayer insulating film 4 and connected to a metal film 5 comprising an aluminum film through a connecting hole 4a. The metal film 5 is covered with an interlayer insulating film 6 and connected to a third wiring layer 7 such as an aluminum film through a connecting hole 6a, which is provided in the interlayer insulating film 6. The connecting holes 4a and 6a are provided so that the center lines of the holes are shifted to each other. The holes are not overlapped. Therefore, the surface of the metal film 5, which is exposed at the connecting hole 6a, becomes flat. Thus the aspect ratio of the connecting hole 6a can be made to be a small value, which is determined by the diameter of the hole and the thickness of an interlayer insulating film 6. In this way, the step coverage of the third wiring layer 7 at the connecting hole 6a can be made excellent.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a semiconductor integrated circuit device, and particularly to a semiconductor integrated circuit device.

The present invention relates to a technique that is effective when applied to a semiconductor integrated circuit device having a multilayer wiring structure.

[Prior Art] In recent years, as LSIs have become highly integrated, wiring has become more multilayered. Japanese Patent Publication No. 54-6704 discloses, for example, the following technique for directly connecting the first layer of aluminum wiring and the third layer of aluminum wiring in an LSI using three-layer wiring. That is, an aluminum film of a predetermined shape is formed using the aluminum film for forming the second layer wiring, and -
The X'Jth wiring and the third layer wiring are connected. In this case, the first layer wiring and the second layer aluminum 11 are connected, and the second layer aluminum 11! The second layer wiring and the third layer wiring are connected by connecting X and the third layer wiring, but the connection for connecting the first layer wiring and the second layer aluminum film is The hole (hereinafter referred to as the "lower connection hole") and the connection hole for connecting the second layer aluminum film and the third layer wiring (hereinafter referred to as the "upper connection hole") are defined by their center lines. are provided so that they match each other.

[Problem that the invention seeks to solve]

However, since the surface of the second layer of aluminum film in the lower connection hole is usually significantly concave, the depth of the upper connection hole is effectively increased by this amount.
The aspect ratio is effectively increased. Therefore, if the center lines of the lower connection hole and the upper connection hole coincide with each other as described above, the step coverage of the third layer wiring in the upper connection hole is extremely poor, and therefore the first layer There was a problem in that it was difficult to make a good connection between the wiring in the third layer and the wiring in the third layer.

An object of the present invention is to provide a technique that can connect upper layer wiring and lower layer wiring well.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of one typical invention disclosed in this application is as follows.

That is, the connection hole for connecting the lower layer wiring and the conductor film and the connection hole for connecting the conductor film and the upper layer wiring are staggered from each other.

[Effect]

According to the above means, it is possible to improve the step coverage of the upper layer wiring in the connection hole for connecting the conductor film and the upper layer wiring.

The upper layer wiring and the lower layer wiring can be well connected.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

In addition, in all the figures for explaining the embodiment, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

FIG. 1 shows an LS with a three-layer wiring structure according to an embodiment of the present invention.
FIG. 2 is a plan view showing I, and FIG. 2 is a sectional view taken along the line XX in FIG. 1.

As shown in FIGS. 1 and 2, the LSI according to this embodiment
In this method, for example, an S
An interlayer insulating film 2 such as an iO2 film is formed, and a first layer wiring (lower layer wiring) 3 such as an aluminum film is provided on this interlayer insulating film 2. This wiring 3 is covered with an interlayer insulating film 4 such as a SiO□ film,
A metal film 5 made of, for example, a rectangular aluminum film is connected to the wiring 3 through a connection hole 4a provided in the interlayer insulating film 4. This metal film 5 can be formed at the same time as, for example, processing an aluminum film for forming a second layer wiring (not shown). This metal film 5 is covered with an interlayer insulating film 6, and a third layer a7 such as an aluminum film is connected to the metal film 5 through a connection hole 6a provided in this interlayer insulating film 6. In this way, the first layer wiring 3 and the third layer wiring 7 are connected via the metal film 5.

In this case, the connecting holes 4a and 6a are provided with their center lines shifted from each other and do not overlap with each other. That is, as shown in FIGS. 1 and 2, the connection hole 4
If the distance between a and 6a is represented by S, it becomes S2O. Therefore, the surface of the metal film 5 exposed in the connection hole 6a becomes flat as shown in FIG.
The aspect ratio of can be set to a small value determined by the diameter and the thickness of the interlayer insulating film 6. Therefore, it is possible to improve the step coverage of the third layer wiring 7 in the connection hole 6a, thereby eliminating the risk of disconnection and reducing contact resistance.

Thereby, the first layer wiring 3 and the third layer wiring 7 can be well connected. As a result, it becomes possible to directly connect the first layer wiring Ra3 and the third layer wiring 7 at any position, so that the degree of freedom in wiring increases and the efficiency of wiring can be improved. This makes it possible to improve the degree of integration. Further, by sufficiently reducing the area of the metal film 5, the decrease in the area that can be used for the second layer wiring can be minimized. Note that the connection holes 4a and 6a may be vertical connection holes or tapered connection holes.

Although the present invention has been specifically described above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof.

For example, in the above embodiment, S≧0, but if the diameter of the connecting hole 4a is d, then at least s > −d
Moreover, the shape of the metal film 5 can be made into various shapes other than a rectangle, and it can also be made of a metal other than an aluminum film or other low-resistance conductive film. Furthermore, in the above-described embodiments, the case where the present invention is applied to an LSI with a three-layer wiring structure has been described.

For example, the present invention can be applied to an LSI having a four-layer wiring structure as shown in FIG. In this case.

The first layer is made using the second layer metal film 5□ and the third layer metal film 5□! ! ? I3 and the fourth layer wiring 8 can be well connected. In FIG. 3, reference numeral 9 is an interlayer insulating film, and reference numeral 9a is a connection hole. The present invention can be similarly applied to LSIs having five or more layers of wiring.

【Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, the upper layer wiring and the lower layer wiring can be well connected.

[Brief explanation of the drawing]

FIG. 1 shows an LS with a three-layer wiring structure according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along x-xi in FIG. 1; FIG. 3 is a sectional view showing a modification of the present invention. In the figure, 1... Semiconductor substrate, 2.4, 6.9... Interlayer insulating film, 4a, 6a, 9a... Connection hole, 3... Wiring (lower layer wiring), 5... Metal Film (conductor film), 7.8・
...Wiring (upper layer wiring).

Claims (1)

[Claims] 1. A plurality of layers of wiring separated from each other by an insulating film, and an upper layer wiring and a lower layer wiring in these multiple layers of wiring are formed by a conductive film located between the upper layer wiring and the lower layer wiring. A semiconductor integrated circuit device in which a connection hole for connecting the lower layer wiring and the conductor film and a connection hole for connecting the conductor film and the upper layer wiring are connected to each other. A semiconductor integrated circuit device characterized by being provided in a staggered manner. 2. The semiconductor integrated circuit device according to claim 1, wherein the connection holes do not overlap each other. 3. The semiconductor integrated circuit device according to claim 1 or 2, wherein the upper layer wiring, the lower layer wiring, and the conductive film are made of an aluminum film.