JPH0239527A - Metallic silicide film forming method - Google Patents

Abstract

PURPOSE:To obtain a metallic silicide film excellent in adhesion and uniformity by forming a metallic silicide film and a polysilicon film excellent in adhesion on a substrate to be treated, and then forming a metallic silicide film on this polysilicon film CONSTITUTION:A barrier iayer and a natural oxide film layer SiO2 13 are formed on a silicon substrate 12. In the case of forming a WSi2 film on a silicon substrate like this, the silicon substrate 12 is placed on a susceptor 11, and then material gas for polysilicon film is introduced into a reaction container so that it may keep the specified vacuum degree. And by heating the susceptor 11, a polysilicon film 14 is formed. And the silicon substrate 12 is carried out of the reaction container. Next, the inside of the reaction container is made the WSi2 film formation treatment atmosphere, and again the silicon substrate 12 is carried into the reaction container, and after raising the temperature of the silicon substrate 12 up to the specified treatment temperature by the susceptor 11, material gas is introduced into the reaction container, and film formation treatment is done only for a specified treatment time so as to form a WSi2 film 15. Hereby, a film excellent in adhesion with the substrate to be treated and uniformity can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for forming various metal silicide films such as WSi2, MoSi2, TiSi2, etc.

(Prior art) Recent highly integrated semiconductor devices such as VLS
An important problem in devices such as I is the problem of parasitic resistance that limits operating speed, and in MOS devices, gate resistance, source/drain resistance, and contact resistance are major factors that affect operating speed. Such parasitic resistance increases as the device becomes smaller, so in order to lower this resistance, WSi2, MoSi2, TiSi
A technique using a metal silicide film of grade 2 has been developed.

One of the methods for forming such a silicide film is CV
A film forming method using the D method is used.

In a film forming method using the CVD method, a substrate to be processed, such as a semiconductor wafer, is placed on a substrate to be processed, such as a susceptor made of carbon graphite, in a reaction vessel, and the susceptor is heated to heat the semiconductor wafer at a predetermined temperature, for example, 600°C. In the above, the W Si 2 film was deposited using the raw material gas, for example, a mixed gas of 5iH2C2 and WF6.

(Problems to be Solved by the Invention) However, in the conventional method of forming a metal silicide film using the CVD method described above, as shown in FIG. When the 5i02 film 3 is formed as a layer or as a natural oxide film, the adhesion between the 5i02 film 3 and the metal silicide 4 to be formed is poor, making the metal silicide film formation unstable and resulting in uniformity. There was a problem that the value decreased.

The method of the present invention was developed to solve the above-mentioned problems, and it suppresses the growth of a natural oxide film on the surface of a substrate to be processed, and also improves adhesion and uniformity even on a substrate to be processed on which a natural oxide film has been formed. It is an object of the present invention to provide a method for forming a metal silicide film that can form an excellent metal silicide film.

[Structure of the Invention] (Means for Solving the Problems) The method for forming a metal silicide film of the present invention includes a step of forming a polysilicon film on a substrate to be processed, and forming a metal silicide film on the polysilicon film. The invention is characterized by comprising the steps of:

(Function) The present invention first forms a polysilicon film with good adhesion to a metal silicide film on a substrate to be processed, and then forms a metal silicide film on this polysilicon film, thereby reducing the natural It is possible to suppress the growth of the oxide film and to improve the adhesion and uniformity of the metal silicide film.

(Example) Hereinafter, an example in which the method of the present invention is applied to a method for forming a W Si 2 film will be described with reference to the drawings.

A substrate to be processed, such as a silicon substrate 12, is adsorbed to a substrate to be processed, such as a susceptor 11, disposed within the reaction vessel.

On the silicon substrate 12, 5iO213, which is a barrier layer or a natural oxide film layer, is formed.

In the method of forming a W Si 2 film on a silicon substrate, first, after placing the silicon substrate 12 on the susceptor 11, a raw material gas for polysilicon film formation is supplied to the reaction vessel so as to maintain a predetermined degree of vacuum. For example, SiH4 or 5iH2C
Introduce raw material gas such as ℃2. The processing temperature at this time is
For example, the susceptor 11 is heated so that the silicon substrate 12 has a temperature of 650° C., and the thickness is reduced to 100 to 200° C., for example.
A polysilicon film 14 is formed.

After forming the polysilicon film 14 in this manner, the silicon substrate 12 is first transported out of the reaction vessel, for example, to a vacuum load lock chamber, by a transport mechanism (not shown).

After that, the inside of the reaction vessel is made into a WSi2 film forming processing atmosphere, the silicon substrate 12 is carried into the reaction vessel again, and the susceptor 1
1, the silicon substrate 12 is heated to a predetermined processing temperature, e.g.
After raising the temperature to 0°C, for example, 5iH2 is used as the raw material gas.
Cβ2+WF6 gas etc. are introduced into the reaction vessel, and a film is formed for a predetermined processing time, e.g. about 1 hour, to a thickness of e.g.
00 W Si 2 film 15 is formed.

Since the W Si 2 film 15 has good adhesion to the polysilicon film 14, by forming the W Si 2 film 15 through the polysilicon thin film 14 as described above,
Stable film formation and uniform thin film can be obtained.

Further, the polysilicon film 14 may be a so-called base film for improving adhesion with the WSi2 film 15, so its film thickness may be very thin.

According to the method of this embodiment, the thin film structure on the silicon substrate 12 has a two-layer structure of the polysilicon film 14 and the W Si 2 film 15. Since the film 14 is diffused into the 5i02 film 13 and becomes uniform, problems due to the two-layer structure do not occur.

Further, the change in resistivity due to the polysilicon film 14 is caused by metal elements in the metal silicide film, for example, the WSi2 film 1 during film formation.
This can be corrected by adjusting the W content in 5.

By the way, as a CVD apparatus for realizing the method of the present invention,
Various methods can be considered, but for example, as shown in FIG. 2, when using a multi-chamber type CVD apparatus equipped with a plurality of chambers centered around a vacuum load-lock chamber 21,
For example, the first chamber 22 is configured as a chamber for cleaning processing, the second chamber 23 is configured as a chamber for forming a polysilicon film, and the third chamber 24 is configured as a chamber for forming a W Si 2 film. Processing may be performed by sequentially moving to these chambers 22, 23, and 24 via the vacuum load lock chamber 21.

In addition, when using a single chamber type CVD apparatus as shown in FIG. After the substrate 25 is once carried out and the inside of the chamber 31 is made into an atmosphere for forming a W Si 2 film, the substrate 25 to be processed may be carried into the chamber 31 again and processed.

Incidentally, during the processing by each of the above-mentioned apparatuses, it is desirable that the apparatus be kept in a vacuum atmosphere during transportation from the viewpoint of suppressing the growth of a natural oxide film.

In the above-mentioned embodiment, the metal silicide film is W Si
Although the method for forming two films has been described, the present invention is not limited thereto; for example, MoSi2, TiSi2,
It is also applicable to other methods of forming metal silicide films such as No. 2.

As described above, the method of the present invention can be easily applied to existing CVD equipment, and the effects of the application are significant.

[Effects of Development] As explained above, according to the present invention, a film with excellent adhesion and uniformity to the substrate to be processed can be formed. 2 and 3 are diagrams showing an example of a CVD apparatus to which the method of the present invention is applied, and FIG. 4 is a cross-sectional view of a substrate to be processed for explaining the method. FIG. 3 is a cross-sectional view of a processed substrate.

11... Susceptor, 12... Silicon substrate, 13... Polysilicon film, 14...
...WS i 2 membrane.

Claims (1)

[Claims] A method for forming a metal silicide film, comprising the steps of forming a polysilicon film on a substrate to be processed, and forming a metal silicide film on the polysilicon film.