KR19980065662A - Method for forming multilayer wiring of semiconductor device - Google Patents

Abstract

A method for forming a multilayer wiring of a semiconductor device is described. This method includes: forming an insulating film on the lower layer, forming a hole partially exposing the lower layer, forming a silicon spacer on the sidewall of the hole, forming a metal film on the entire surface of the resulting substrate on which the silicon spacer is formed, Plasma or heat treatment of the resulting substrate on which the metal film is formed in a gas atmosphere containing nitrogen to silicide the silicon spacer and to nitride the metal film, and to partially etch the nitrided metal film to expose the surface of the insulating film. A step of embedding tungsten and a step of sequentially laminating a barrier film and an aluminum film on the entire surface of the resultant substrate in which tungsten is buried;

Description

Method for forming multilayer wiring of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for forming a multilayer wiring of a semiconductor device in which tungsten is buried to connect upper and lower conductive films.

As the devices are highly integrated, a multi-layered wiring is required. However, due to the multi-layered wiring structure, the contact hole or via hole becomes smaller and the aspect ratio increases, so that aluminum (Al) and copper (Cu) may be used to improve the device speed. , Contact holes or via holes should be buried using materials with low resistivity, such as tungsten (W).

1 to 4 are cross-sectional views illustrating a method of forming a multilayer wiring of a conventional semiconductor device.

An insulating film 12 having a hole 1 partially exposing the lower film is formed on a lower film 10 made of a metal film such as a silicon substrate or aluminum (FIG. 1), and the resultant in which the insulating film is formed. After forming the first barrier film 14 made of, for example, a layer of titanium and titanium nitride (Ti / TiN) or a titanium nitride film (TiN) on the entire surface of the substrate, the tungsten may be completely embedded in the hole. A film 16 is deposited (FIG. 2).

Subsequently, the tungsten film and the first barrier film are etched by a chemical mechanical polishing (CMP) method until the surface of the nitride film 12 is exposed (FIG. 3), and then the entire surface of the resultant substrate, eg titanium And a second barrier film 20 made of a titanium nitride film and a titanium nitride film and an aluminum film 22 are sequentially stacked (FIG. 4).

According to the conventional multi-layered wiring method described above, the first barrier film 14 is thinly deposited in the corner portion of the hole 1 (indicated by A), and thus cannot act as a barrier between the tungsten and the lower film and leaks. There is a problem that causes a current.

In the case of the via hole structure (when the lower layer 10 is a conductive layer), when the current density is applied to the corner portion, the first barrier layer may act as a barrier between the lower layer and tungsten. There is a problem in that a short circuit or a hilock occurs in the wiring.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a multilayer wiring of a semiconductor device in which a barrier film formed between tungsten and a lower film can play its role with high reliability.

1 to 4 are cross-sectional views illustrating a method of forming a multilayer wiring of a conventional semiconductor device.

5 to 9 are cross-sectional views illustrating a method of forming a multilayer wiring of a semiconductor device according to the present invention.

According to an aspect of the present invention, there is provided a method of forming a multilayer wiring of a semiconductor device, the method comprising: forming an insulating film on a lower film, and then forming a hole partially exposing the lower film; Forming a silicon spacer on sidewalls of the hole; Forming a metal film on the entire surface of the resultant substrate on which the silicon spacers are formed; Silicifying the silicon spacer and nitriding the metal film by plasma or heat treatment of the resultant substrate on which the metal film is formed in a gas atmosphere containing nitrogen; Partially etching the nitrided metal film to expose the surface of the insulating film; Embedding tungsten in the hole; And laminating a barrier film and an aluminum film sequentially on the entire surface of the resultant substrate in which tungsten is buried.

In the method for forming a multilayer wiring according to the present invention, the lower layer is any one of a silicon substrate and a lower conductive layer, and the metal layer is titanium (Ti), cobalt (Co), platinum (Pt), tungsten (W) and hafnium. It is preferably made of a metallic material capable of ohmic contact with a lower film such as (Hf).

In the method for forming a multilayer wiring according to the present invention, the nitrogen-containing gas is any one of nitrogen (N 2) and ammonium (NH 3), and the barrier film is a titanium nitride film and a film in which titanium and titanium nitride are laminated. It is preferable that it is either.

Hereinafter, with reference to the accompanying drawings, it will be described in more detail the present invention.

5 to 9 are cross-sectional views illustrating a method of forming a multilayer wiring of a semiconductor device according to the present invention.

For example, an insulating film 32 having a hole 3 partially exposing the lower film is formed on a lower film 30 made of a metal film such as a silicon substrate or aluminum, and the resulting substrate having the insulating film 32 formed thereon. The silicon film 34a is deposited on the entire surface. At this time, the silicon film 34a is formed not only on the insulating film 32 but also on the lower film exposed by the sidewalls and the holes 3 (FIG. 5).

Subsequently, the silicon film is anisotropically etched to form silicon spacers 34 on the sidewalls of the holes. For example, titanium (Ti), cobalt (Co), and platinum (Pt) are formed on the entire surface of the resulting substrate on which the silicon spacers 34 are formed. ), A metal film 36 is formed by depositing a metal material capable of ohmic contact with the lower layer 30 such as tungsten (W) or hafnium (Hf) (FIG. 6).

Subsequently, the resultant substrate having the metal film formed thereon, for example, by plasma or heat treatment in a gas atmosphere containing nitrogen such as nitrogen (N 2) or ammonium (NH 3) to form the silicon particles and the metal film constituting the silicon spacer. The silicide spacer 34b and the metal nitride film 36a are formed by bonding the metal particles to be silicided to form a silicide and bonding and nitriding the particles of the metal film to nitrogen particles (Fig. 7).

After depositing tungsten (W) on the resultant substrate on which the silicide spacers 34b and the metal nitride film 36a are formed, the tungsten and metal nitride films are chemically deposited until the top surface of the insulating film 32 is exposed. Etch with physical poly (CMP) (FIG. 8).

Thereafter, a barrier film 40 made of, for example, a film in which titanium and titanium nitride are laminated or a titanium nitride film is formed on the entire surface of the resultant substrate subjected to CMP, and on the barrier film 40, the aluminum film 42 is formed. To form (FIG. 9).

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical idea of the present invention.

According to the method for forming a multilayer wiring according to the present invention, since the silicide is formed at the corners of the holes, there is an advantage of improving the ohmic contact property with the lower layer, and a double nitrided metal film is formed on the silicide layer. Because of this, the barrier effect of the barrier layer is better.

Claims (5)

Forming an insulating film on the lower film, and then forming a hole that partially exposes the lower film; Forming a silicon spacer on sidewalls of the hole; Forming a metal film on the entire surface of the resultant substrate on which the silicon spacers are formed; Silicifying the silicon spacer and nitriding the metal film by plasma or heat treatment of the resultant substrate on which the metal film is formed in a gas atmosphere containing nitrogen; Partially etching the nitrided metal film to expose the surface of the insulating film; Embedding tungsten in the hole; And laminating a barrier film and an aluminum film in order on the entire surface of the resultant substrate in which tungsten is buried. The method of claim 1, wherein the lower layer is any one of a silicon substrate and a lower conductive layer. The method of claim 1, wherein the metal film is made of a metallic material capable of ohmic contact with a lower film such as titanium (Ti), cobalt (Co), platinum (Pt), tungsten (W) and hafnium (Hf). A multilayer wiring forming method of a semiconductor device. The method of claim 1, wherein the gas containing nitrogen is any one of nitrogen (N 2) and ammonium (NH 3). The method of claim 1, wherein the barrier film is any one of a titanium nitride film and a film in which titanium and titanium nitride are stacked.