JP3002007B2 - Manufacturing method of tungsten film and multilayer film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CVD method widely used in industry, and more particularly to a method of manufacturing a tungsten film and alternately laminating tungsten and carbon used in an X-ray optical element or the like. To provide a method for manufacturing a multilayer film.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a tungsten (hereinafter referred to as W) film, a CVD method of decomposing a material gas supplied into a reaction vessel into active particles and forming a film on a substrate has been widely used. I have. For example, Applied Physics Letters, Vol. 45, p. 623, 1984 (Applie
d Physics Letters 45, 623 (1984)). Hereinafter, a method of manufacturing a W film by the CVD method will be described. In accordance with film forming the CVD method, supplying a gas containing a constituent element of the at least film into the reaction vessel, which ions, by decomposing the active particles such as radicals, film on a substrate placed in a reaction vessel Is deposited. As a material gas containing W, there are tungsten halide such as tungsten hexafluoride, tungsten carbonyl and the like. In the case of forming a W film, these gases are generally diluted with a rare gas such as helium or argon and used. I have.
However, when only tungsten hexafluoride and a rare gas are supplied as material gases, there is a problem that etching occurs simultaneously with film formation due to fluorine contained in tungsten hexafluoride, the film is not smooth, and the like. A technique such as adding hydrogen to tungsten oxide and supplying it is used. The mixing ratio of hydrogen and tungsten hexafluoride at this time is, for example,
The ratio of hydrogen to tungsten hexafluoride is very large, about 50 to 1.

[0003] A multilayer film (hereinafter referred to as a W / C multilayer film) in which tungsten and carbon are alternately laminated has been used as an X-ray optical element or the like. W using a so-called photo-CVD method using light
/ C multilayer film is being formed. For example, Japanese Journal of Applied Physics, Vol. 28, p. 920, 1989 (Japanese Journal of Applied Physics)
Applied Physics 28 , 920 (1989)). Hereinafter, a method of manufacturing a W / C multilayer film using a photo-CVD method will be described.

In the formation of a multilayer film by the photo-CVD method, first,
A gas containing a constituent element of a film to be deposited is supplied into a reaction vessel, and is irradiated with light to be decomposed into active particles, and the film is deposited on a substrate provided in the reaction vessel. Each time one layer is deposited, the inside of the reaction vessel is evacuated, and the supplied gas is switched to alternately deposit a film to form a multilayer film. W /
When a C multilayer film is formed, benzene, acetylene, or the like is used as a material gas for the C film, and three kinds of gases such as tungsten hexafluoride, hydrogen, and a rare gas are used as the material gases for the W film as described above. Is used, and four or more kinds of material gases are required for forming a multilayer film.

[0005]

However, the above-mentioned conventional structure has a problem that hydrogen must be added several tens times to tungsten hexafluoride, and the density of the formed tungsten film is reduced. I was In addition, since hydrogen has a risk of explosion or the like, there is a problem that handling of gas and equipment become complicated. Further, at least four types of gases are required as material gases when forming the W / C multilayer film, and there is a problem that the apparatus system becomes complicated.

An object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a method of manufacturing a W film which does not cause etching or the like without using a dangerous gas such as hydrogen. In particular, it is an object of the present invention to reduce a material gas when forming a W / C multilayer film and to simplify a multilayer film manufacturing apparatus.

[0007]

In order to achieve the above object, the present invention provides a method for forming a W film on a substrate by decomposing a material gas supplied into a reaction vessel into active particles such as ions and radicals. In addition, at least a hydrocarbon gas is added to a tungsten halide such as tungsten hexafluoride as a material gas. Further, when a W / C multilayer film is formed by using the CVD method, a hydrocarbon gas for forming a C film is added to a tungsten halide gas as a material gas for forming the W film. . Examples of the hydrocarbon gas include benzene. As a means for decomposing into active particles, for example, there is a photo-CVD method using light. Further, the ratio of benzene to tungsten hexafluoride may be at most 10%.

[0008]

According to the present invention, a W film having no etching or the like can be obtained without using a dangerous gas such as hydrogen. In particular, when forming a W / C multilayer film, only three systems of gases need to be supplied, and the gas supply system of the multilayer film manufacturing apparatus can be simplified.

[0009]

【Example】

Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an apparatus for manufacturing a W film and a W / C multilayer film using an excimer laser CVD method according to an embodiment of the present invention. In FIG. 1, 11 is a reaction vessel, 12 is a substrate holder, 13 is a substrate, 14 is an exhaust port,
Reference numeral 15 denotes a material gas inlet, and reference numeral 16 denotes an excimer laser beam.

The operation of the manufacturing apparatus configured as described above when forming a W film will be described. First, a substrate 1 for forming a film on a substrate holder 12 in a reaction vessel 11 is formed.
3 is installed, the reaction vessel 11 is sealed, and the inside of the reaction vessel 11 is evacuated from the exhaust port 14 to a high vacuum. Next, the substrate 13 is heated to a predetermined temperature, and the reaction vessel 1 is introduced through the material gas inlet 15.
Tungsten hexafluoride, benzene, and helium are introduced into 1 at a constant gas pressure ratio. This gas pressure ratio is, for example, 3
0: 1: 450 (sccm). Then, the material gas is irradiated with excimer laser light 16 to decompose the material gas into active particles, and a W film is formed on the substrate 13.

When forming a W / C multilayer film, the inside of the reaction vessel 11 is evacuated to a high vacuum, and then benzene and helium are introduced into the reaction vessel 11 at a constant gas pressure ratio. Then, a C film is formed on the substrate 13. After forming a C film having a desired thickness, the inside of the reaction vessel 11 is evacuated again, and then tungsten hexafluoride, benzene, and helium are supplied at a constant gas pressure ratio, for example, 30: 1: 450 (scc).
m), and is irradiated with excimer laser light 17 to form a W film. By repeating the above operation, a W / C multilayer film having a desired number of layers can be formed.

FIGS. 2A and 2B show a W / C multilayer film formed by an excimer laser CVD method using the manufacturing apparatus shown in FIG. 1 and a W / C film formed by a conventional vapor deposition method, respectively. 9 is a profile of W obtained by RBS measurement of a C multilayer film. The horizontal axis represents the kinetic energy of the backscattered particle, which is the position of the scattered particle,
That is, it corresponds to the depth direction. The vertical axis represents the scattering intensity. 2 (a) and 2 (b), the surface is around 16 keV, and the profile of the W layer for five layers from the surface is observed, and almost the same profile is obtained. It can be seen that the W film formed using the manufacturing apparatus has a composition similar to that of the vapor deposition method. That is, in the present production method, active particles such as C 2 and CH obtained by decomposing benzene do not directly contribute to film formation, but are bonded to fluorine contained in tungsten hexafluoride and exhausted. The formed film becomes a W film.

The material gases used in the first embodiment are tungsten hexafluoride as another tungsten halide, benzene as another hydrocarbon gas such as acetylene, and helium as another rare gas such as argon. It may be used in place of gas. Further, although an excimer laser is used here to decompose the material gas into the active particles, it goes without saying that other means may be used.

[0015]

As described above, according to the present invention, when a material gas supplied into a reaction vessel is decomposed into active particles to form a W film on a substrate, at least benzene or the like is added to the tungsten halide as a material gas. By adding the above hydrocarbon gas, it is possible to realize the production of a W film without etching without using a dangerous gas such as hydrogen. In particular, when forming the W / C multilayer film, the gas supply system of the manufacturing apparatus can be simplified by reducing the number of material gas systems.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an apparatus for manufacturing a W thin film and a W / C multilayer film using an excimer laser CVD method according to a first embodiment of the present invention.

FIG. 2 (a) RBS measurement of a W / C multilayer film formed by an excimer laser CVD method using the manufacturing apparatus shown in FIG.
Shows the profile of a W obtained by the constant (b) RB of W / C multilayer film formed by a conventional vapor deposition method
The figure which shows the profile of W obtained by S measurement.

[Explanation of symbols]

 Reference Signs List 11 reaction vessel 12 substrate holder 13 substrate 14 exhaust port 15 material gas inlet 16 excimer laser beam

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 C23C 28/00 JICST file (JOIS)

Claims (6)

(57) [Claims] When a tungsten halide gas supplied into a reaction vessel is decomposed into active particles such as ions and radicals to form a tungsten film on a substrate, the gas contains at least hydrocarbons other than hydrogen gas. A method for producing a tungsten film, characterized by adding a gas. 2. A method for forming a tungsten film in a case where a material gas supplied into a reaction vessel is decomposed into active particles such as ions and radicals to form a multilayer film in which a tungsten film and a carbon film are alternately stacked. A method of manufacturing a multilayer film, wherein at least hydrogen carbide gas for forming a carbon film is added to a tungsten halide gas as the material gas. 3. The method according to claim 1, wherein the hydrocarbon gas is benzene. 4. The method according to claim 1, wherein light is used to decompose the material gas into active particles. 5. The method according to claim 1, wherein the hydrocarbon gas is benzene, and light is used to decompose the material gas into active particles. 6. The hydrocarbon gas is benzene, and the ratio of the gas added to the tungsten halide gas is 10%.
%.