JPH07153716A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an electrode wiring of a semiconductor device and a forming method thereof, wherein particles are less produced in a manufacturing process to enhance the electrode wiring in properties of barrier. CONSTITUTION:A titanium(Ti) film 5 is formed on the primary surface of a silicon substrate 1, a tungsten (W) film 6 is formed on the titanium(Ti) film 5, and a laminated film composed of the titanium (Ti)film 5 and the tungsten (W) film 6 is annealed in an oxygen-free atmosphere of nitrogen or ammonia gas for the formation of a barrier layer composed of a titanium silicide film 7, a Ti-W allay film 8, and a tungsten nitride film 9. As the Ti-W alloy film 8 and the tungsten nitride film 9 both high in fragility are not formed direct through a sputtering method, particles are less produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to electrode wiring of a semiconductor device having a barrier layer between an aluminum-based wiring made of an aluminum film or an aluminum alloy and a silicon substrate, and a method of forming the same. .

[0002]

2. Description of the Related Art In a semiconductor integrated circuit or the like, an aluminum alloy (for example, Al--Si alloy, A
1-Si-Cu alloy) is mainly used. In the wiring on the impurity diffusion layer, a conductive film called a barrier layer is generally formed between the aluminum alloy film and the impurity diffusion layer. The barrier layer suppresses mutual diffusion of aluminum (Al) and silicon (Si), and prevents leakage current between the semiconductor substrate and the impurity diffusion layer due to erosion of the impurity diffusion layer formed on the semiconductor (Si) substrate. It is to prevent the increase.

A conventional electrode wiring including a barrier layer and a method for manufacturing the same will be described below.

In the conventional example shown in FIG. 5, for example, an N type impurity diffusion layer 4 is formed on the main surface of a semiconductor substrate (P type silicon substrate 1).
After the insulating film 2 is formed and the impurity diffusion layer is exposed by anisotropic etching or the like, T is formed by a sputtering method using a Ti—W alloy as a barrier layer as a target.
The i-W alloy film 8C is formed. This Ti-W
The aluminum alloy film 10 (for example, Al
-Si film or Al-Si-Cu film) is formed, and an unnecessary portion of the two-layer film of the aluminum alloy film 10 and the Ti-W alloy film 8C is removed by anisotropic etching or the like. The formation is complete. It is also known to use a tungsten film as a barrier layer or a tungsten nitride film formed by a reactive sputtering method using tungsten as a target instead of the Ti—W alloy film.

Further, the conventional example shown in FIG. 6 has a structure in which a laminated film in which a titanium film 5C is provided under a Ti-W alloy film 8D film is used as a barrier layer.
It is disclosed in the publication. Both the titanium film and the Ti-W alloy film are sequentially formed by a sputtering method using Ti and Ti-W alloy as targets, respectively.
Further, a titanium silicide film 7C (TiSi ₂ film) is formed between the impurity diffusion layer 4 and the titanium film 5C to secure a stable electrical connection between the impurity diffusion layer 4 and the aluminum alloy film 10.

[0006]

In the conventional example described above, the one using the tungsten film as the barrier layer has a poor barrier property and suppresses interdiffusion between silicon of the silicon substrate and aluminum of the aluminum-based wiring layer. Is insufficient.

The one using a Ti-W alloy film as the barrier layer has a better barrier property than the tungsten film. However, there are still problems with barrier properties. The barrier property deteriorates during the operation of the semiconductor device because titanium reacts with aluminum and the concentration of silicon in the wiring layer containing silicon such as Al-Si and Al-Si-Cu decreases, and silicon from the substrate is reduced. It is considered that this is because the diffusion of is likely to occur. The titanium silicide film formed between the Ti—W alloy film and the silicon substrate has an advantage that the contact resistance is low, but the deterioration of the barrier property is the same as that described above.

Although the tungsten nitride film has a good barrier property, it cannot be brought into direct contact with silicon. This is because nitrogen reacts with silicon.

After all, none of them can sufficiently prevent the reaction between the aluminum-based wiring layer or the barrier layer and the silicon substrate, and when the impurity diffusion layer and the silicon substrate form a PN junction, impurities cannot be formed. There is a problem that the diffusion layer is eroded to increase the leakage current.

In addition, when a Ti-W alloy film is formed by a sputtering method using a Ti-W alloy as a target or a tungsten nitride film is formed by reactive sputtering using a tungsten as a target, a film forming process (cleaning of a sputtering device) is performed. (Including work), particles (dust) are frequently generated, and the yield of semiconductor devices is significantly reduced. This is because the Ti-W alloy film and the tungsten nitride film are highly brittle.

[0011]

The semiconductor device of the present invention comprises:
In a contact hole provided in a predetermined insulating film on a silicon substrate, a titanium silicide film bonded to the silicon substrate at the bottom of the contact hole, a Ti-W alloy film provided on the titanium silicide film, Ti-W
The electrode wiring comprises a titanium nitride film provided on the alloy film and an aluminum-based film covering the titanium nitride film.

The method of manufacturing a semiconductor device according to the present invention is
A step of forming a contact hole in a predetermined insulating film on a silicon substrate, and a titanium film and a tungsten film are sequentially deposited by a sputtering method, and then heat treatment is performed in a nitrogen or ammonia atmosphere to react the silicon substrate with the titanium film. And a titanium silicide film, a step of reacting the titanium film and the tungsten film to form a Ti—W alloy film, and a thermal nitridation of the tungsten film to form a tungsten nitride film, and an aluminum-based conductive film is deposited. And then patterning to form electrode wiring.

[0013]

The semiconductor device of the present invention has a small contact resistance due to the titanium silicide film, a good barrier property due to the tungsten nitride film, and a reaction preventing effect between the silicon substrate and nitrogen due to the Ti-W alloy film. Further, in the method for manufacturing a semiconductor device of the present invention, since the titanium film and the tungsten film, which are less brittle, are formed by the sputtering method, the generation of particles can be suppressed in the degree of film formation. Furthermore,
At the same time as nitriding the tungsten film by thermal nitriding, the titanium silicide film and the Ti—W alloy film are formed, so that the adhesion between the adjacent films can be further improved to form the barrier film.

[0014]

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

FIGS. 1A to 1D are sectional views in order of steps for illustrating one embodiment of the present invention along with its manufacturing steps.

First, as shown in FIG. 1A, a field oxide film is formed on a P-type silicon substrate 1 to partition an element forming region, and transistors (not shown) and the like are formed. Here, the N-type impurity diffusion layer 4 is shown as a representative of these transistors and the like. Then, a silicon oxide-based interlayer insulating film is deposited. In the figure, the field oxide film and the interlayer insulating film are shown as the insulating film 2 as a representative. By forming a contact hole 3 in the insulating film 2 portion above the N-type impurity diffusion layer 4, the surface of the N-type impurity diffusion layer 4 is exposed. After that, the surface of the N-type impurity diffusion layer 4 is washed with various chemicals or the reverse sputtering method, and as shown in FIG. 1B, a titanium (Ti) film 5 is formed to a thickness of 100 nm by the sputtering method. Further, as shown in FIG. 1 (c), titanium (T
i) Tungsten (W) on the film 5 by sputtering
The film 6 is formed to a thickness of 150 nm. Then, the wafer is taken out from the sputtering apparatus and heat-treated for 60 seconds in an ammonia atmosphere containing almost no oxygen, for example, at 1 atm. The temperature of the heat treatment is 800 to 900 ° C., especially 8
50 ° C is preferred. By this heat treatment, as shown in FIG. 1D, alloying occurs at the interface between the titanium (Ti) film 5 and the tungsten (W) film 6 to form a Ti—W alloy film, and at the same time, the tungsten (W) film is formed. The surface of 6 is nitrided to form a titanium nitride film 9, and the titanium film 5 and the N-type impurity diffusion layer 4 react with each other to form a titanium silicide (TiSi ₂ ) layer 7. Then, Al-Si or Al-Si
-The aluminum alloy film 10 such as Cu is deposited, and anisotropic etching is performed to complete the formation of the electrode wiring. This electrode wiring has a four-layer structure of a titanium silicide film 7, a Ti—W alloy film 8, a tungsten nitride film 9 and an aluminum alloy film 10 at the bottom of the contact hole 3, and the titanium silicide film 7 is formed on the insulating film 2. It has a three-layer structure except for.

850 heat treatment in an ammonia atmosphere
As shown in FIG. 2, when the temperature is about 30 seconds, the titanium film 5A
Can be left, and the adhesiveness with the insulating film 2 can be further improved.

Further, instead of an ammonia atmosphere, a nitrogen atmosphere containing almost no oxygen and having an atmospheric pressure of 850 ° C. and 60 ° C.
When heat treatment is performed for about a second, a tungsten film 6A is obtained between the tungsten nitride film 9A and the Ti—W film 8 as shown in FIG. If the time of this heat treatment is set to about 30 seconds, the titanium film 5B can be left as shown in FIG. Whether or not to leave the tungsten film may be determined in consideration of the barrier property of the tungsten nitride film and the low resistance of the tungsten film.

[0019]

As described above, according to the present invention, since the contact portion has the barrier layer composed of the titanium silicide film joined to the silicon substrate, the Ti—W alloy film, and the tungsten nitride film, Electrode wiring having low resistance and excellent barrier properties can be realized, and the electrical characteristics and reliability of the semiconductor device can be improved. Further, since such an electrode wiring is formed by sequentially depositing a titanium film and a tungsten film by a sputtering method and performing thermal nitriding, a Ti—W film is formed by the sputtering method or a reactive sputtering of W. The generation of particles in the sputtering apparatus is smaller than that in film formation, so that the yield and reliability of the semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment of the present invention (a).
It is a process order sectional view divided and illustrated in- (d).

FIG. 2 is a sectional view for explaining a first modification of the embodiment.

FIG. 3 is a sectional view for explaining a second modification of the embodiment.

FIG. 4 is a sectional view for explaining a third modification of the embodiment.

FIG. 5 is a sectional view for explaining a conventional example.

FIG. 6 is a cross-sectional view for explaining another conventional example.

[Explanation of Codes] 1 P-type silicon substrate 2 Insulating film 3 Contact hole 4 N-type impurity diffusion layer 5, 5A, 5B, 5C Titanium film 6, 6A, 6B Tungsten film 7, 7A, 7B, 7C Titanium silicide film 8, 8A, 8B, 8C, 8D Ti-W alloy film 9, 9A, 9B, 9C Tungsten nitride film 10 Aluminum alloy film

Claims (4)

[Claims] 1. In a contact hole portion provided in a predetermined insulating film on a silicon substrate, a titanium silicide film bonded to the silicon substrate at a bottom portion of the contact hole, and a Ti-W film provided on the titanium silicide film. A semiconductor device comprising: an alloy film; a titanium nitride film provided on the Ti-W alloy film; and an electrode wiring comprising an aluminum-based film covering the titanium nitride film. 2. The semiconductor device according to claim 1, wherein a titanium film is interposed between the titanium silicide film and the Ti—W alloy film. 3. The semiconductor device according to claim 1, wherein a tungsten film is interposed between the Ti—W alloy film and the titanium nitride film. 4. A step of forming a contact hole in a predetermined insulating film on a silicon substrate, and a titanium film and a tungsten film are sequentially deposited by a sputtering method and then heat-treated in a nitrogen or ammonia atmosphere to carry out the heat treatment on the silicon substrate and the silicon substrate. Reacting a titanium film with a titanium silicide film, reacting the titanium film with the tungsten film to form a Ti—W alloy film, and thermally nitriding the tungsten film to form a tungsten nitride film; A step of depositing a conductive film and then patterning it to form an electrode wiring.