JPH03296219A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent discontinuity by migration of aluminum between a tungsten film and an aluminum wiring layer by forming a wiring layer of a metal layer including aluminum and tungsten and connecting the tungsten film used for connecting an upper and a lower layers to a metal layer of each wiring. CONSTITUTION:This semiconductor device is formed, on an insulating film 2 on a silicon semiconductor substrate 1, of a tungsten film, a first aluminum wiring layer 4, a layer insulating film 5 deposited on the first aluminum wiring layer 4 with selectively formed openings, a tungsten film 6 which is buried to connect the opening part and the first aluminum wiring removal region under the opening part to a metal film 3, a tungsten film 7 and a second aluminum wiring layer 8. Therefore, discontinuity between the second aluminum wiring layer 8 and tungsten film 6 is never caused.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a semiconductor device, and particularly to a semiconductor device having multilayer wiring.

BACKGROUND OF THE INVENTION Conventional multilayer interconnection is based on a semiconductor substrate 1, as shown in FIG.
1, a first wiring layer such as a first aluminum wiring layer 14, an interlayer insulation film 15, and a second aluminum wiring layer 18. A tungsten film 16 is selectively buried in the opening region of the interlayer insulating film 15, which serves as a connecting portion between the aluminum wiring layer 14 and the second aluminum wiring layer 18, thereby establishing a connection between the aluminum wirings.

This selective tungsten film 16 is used in order to prevent an increase in the level difference of the openings due to the miniaturization of the openings in the interlayer insulating film, and to prevent step breakage or increase in resistance value due to the increase in the aspect ratio of the openings in the upper layer aluminum wiring. It is.

Problems to be Solved by the Invention However, in this conventional multilayer wiring structure, a migration phenomenon occurs when a high current flows through the first and second aluminum wirings 14 and 18 through the tungsten film 16 at the connection portion. In this structure in which the first and second aluminum wirings are connected by the tungsten film 16 of different metals, the migration phenomenon occurs only in the aluminum wiring part, as shown in Fig. 5, at the connection part between the aluminum atoms, which are likely to migrate, and the tungsten atoms, which are difficult to migrate. occurs and aluminum moving area 1
9 is formed, and the second aluminum wiring layer 18 and the tungsten film 1
There was a problem that a disconnection with 6 occurred.

The present invention has been made in view of the above-mentioned conventional situation,
Accordingly, an object of the present invention is to provide a novel semiconductor device that makes it possible to solve the above-mentioned problems inherent in the conventional technology.

Means for Solving the Problems In order to achieve the above object, a semiconductor device according to the present invention includes:
A semiconductor device having a first wiring layer, a second wiring layer formed via an interlayer insulating film, and a tungsten film connecting the first wiring layer and the second wiring layer. The second wiring layer has a laminated structure of an aluminum film and a metal layer containing at least tungsten,
The structure includes a structure in which a metal layer containing tungsten and the tungsten film are connected.

EXAMPLES Next, preferred embodiments of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of the present invention.

Referring to FIG. 1, the first embodiment of the semiconductor device according to the present invention includes a tungsten film with a thickness of about 0.1 μm on an insulating film 2 formed on a silicon semiconductor substrate 1, and a tungsten film with a thickness of about 1 μm on an insulating film 2 formed on a silicon semiconductor substrate 1. A first aluminum interconnection layer 4, an interlayer insulating film 5 deposited on the first aluminum interconnection layer 4 to a thickness of approximately 0.5 μm and selectively having an opening, and a first aluminum interconnection layer at the opening and under the opening. It is composed of a tungsten film 6 buried so as to connect the aluminum wiring removed region to the metal film 3, a tungsten film 7 with a thickness of approximately 0.1 μm, and a second aluminum wiring layer 8 with a thickness of approximately 1 μm. There is.

3(a) and 3(b) are cross-sectional views of the process steps of the embodiment of the bookcase 1, and further explanation will be added. In FIG. 3 (a), a tungsten film 3 is deposited by sputtering on an insulating film 2 formed on a silicon semiconductor substrate 1, and a first aluminum wiring layer 4 with a thickness of about 1 μm is further deposited by sputtering. A tungsten film 3 and a first aluminum wiring layer 4 are formed by photolithography.
pattern at the same time. Next, a wiring interlayer film 5 is formed. Here, the wiring interlayer film 5 is formed by sequentially depositing, for example, a plasma nitride film with a thickness of about 2,000 layers using a plasma CVD method, an organic coating film with a thickness of about 1,000 layers, and a plasma nitride film using a plasma CVD method with a thickness of about 2,000 layers. shall be taken as a thing. Next, the interlayer insulating film 5 is selectively removed by photolithography to expose the first aluminum wiring layer 4, and anisotropic etching is further applied to the exposed first aluminum wiring layer 4 to expose the tungsten film 3. let Next, as shown in FIG. 3(b), a tungsten film 6 is buried in the opening by selective CVD. Next, as shown in FIG. 1, a tungsten film 7 and a second aluminum wiring layer 8 are sequentially deposited by sputter linking and patterned by photolithography.

A titanium-tungsten film can be used instead of the tungsten film 3.7.

A first wiring layer is formed by the tungsten or titanium tungsten film 3 and the first aluminum wiring layer 4, and a second wiring layer is formed by the tungsten or titanium tungsten film 7 and the second aluminum wiring layer. .

A cross section of a second embodiment according to the invention is shown in FIG.

Referring to FIG. 2, a first aluminum wiring layer 4 with a thickness of about IIIm and a titanium-tungsten or tungsten film 3 with a thickness of about 1000m are formed on an insulating film 2 formed on a semiconductor substrate 1 by sputtering. , an interlayer insulating film 5 is formed in the same way as in the first embodiment, and selective CVD is applied to the opening.
The tungsten film 6 formed by the method is buried, and about 1
A titanium tungsten or tungsten film 7 with a thickness of 1,000 μm and an aluminum wiring layer 8 with a thickness of about 1 μm are selectively formed.

Unlike the first embodiment, the second embodiment does not require the step of removing the lower first aluminum wiring to expose the titanium tungsten or tungsten film 3, and is therefore simple in terms of process. Furthermore, the tungsten film 6 that fills the openings
Since the film thickness can be reduced, it is also effective in reducing the resistance value of the opening.

As described in detail, according to the present invention, the wiring layer is formed of a metal layer containing aluminum and tungsten, and the tungsten film used for connecting the upper layer and the lower layer is connected to the metal layer of each wiring. An advantage is obtained that the above-mentioned problem of disconnection due to aluminum migration between the tungsten film and the aluminum wiring layer shown in the figure does not occur.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention,
The figure is a sectional view showing a second embodiment of the present invention, and FIG.
a) to (b) are cross-sectional views showing the process order of the first embodiment of the present invention, FIG. 4 is a cross-sectional view of a conventional example, and FIG. 5 is an explanatory diagram of a conventional aluminum microsion.

Claims (2)

[Claims] (1) A first wiring layer formed on a semiconductor substrate and a second wiring layer formed via an interlayer insulating film, the first wiring layer and the second wiring layer in a semiconductor device in which the first and second metal layers are connected by a first metal layer;
the wiring layer has a laminated structure of at least two types of metals,
The second metal layer has a second metal layer containing atoms in which at least one of the two types of metals constitutes the first metal layer, and the second metal layer constitutes the first and second wiring layers. are connected to each other by the first metal layer. (2) The first metal layer is a tungsten layer, the second metal layer is titanium tungsten or a tungsten layer, and the first and second wiring layers are made of aluminum and the second metal layer. The semiconductor device according to claim 1, further characterized in that it has a layered structure.