JPH0759751B2 - Thin film manufacturing method - Google Patents

Description

The present invention relates to a method for producing a thin film, and more particularly to a method for producing a thin film by dynamic mixing in which ion beam implantation and vapor deposition are performed simultaneously.

[Prior Art] Conventionally, a so-called dynamic mixing method has been used as a method for manufacturing a thin film (for example, the 29th method).
Proceedings of the 1st Joint Lecture of Applied Physics 1a-A-1 (1982). The method of producing a thin film by this dynamic mixing is several
It is intended to simultaneously implant an ion beam having an energy of 10 kV or more into a substrate and deposit it onto the substrate using sputtering or evaporation.

[Problems to be solved by the invention]

However, the conventional thin film manufacturing method by dynamic mixing has a problem in that the actually manufactured thin film contains a large amount of impurities such as carbon and oxygen in the vacuum container. The cause of such impurities is considered to be the hydraulic oil vapor flowing back from the oil diffusion pump, the water adsorbed on the surface of the apparatus, and the like.

Therefore, in order to reduce the influence of impurities to any extent, it was necessary to use a turbo or a cryopump capable of forming a thin film in a high vacuum.

However, even if such a pump is used, the influence of impurities cannot be eliminated, and therefore various properties such as peeling resistance and strength of the thin film cannot be said to be sufficient.

In order to solve such a problem, it is an object of the present invention to provide a method that enables the production of a thin film having a low content of impurities and, as a result, excellent in various characteristics.

[Means for solving problems]

The present invention, in order to achieve the above object, in a method for producing a thin film in which a thin film is formed on a substrate surface by performing ion implantation and vapor deposition at the same time, the ion implantation is performed with ion energy of more than 10 keV and ions on the thin film surface. This method proposes a method for producing a thin film in which the current density is 0.3 mA / cm ² or more and the vapor deposition rate of vapor deposition particles on the thin film surface is 3 Å / sec or more.

[Action]

According to the above configuration of the present invention, the amount of implanted ions and vapor deposition particles that reach the substrate surface per unit time can be made significantly larger than the amount of impurities from the vacuum container that reach the substrate surface. As a result, the content of impurities in the thin film can be significantly reduced.

In the present invention, in particular, since the ion implantation is performed so that the ion energy is larger than 10 keV and the ion current density on the thin film surface is 0.3 mA / cm ² or more, the penetration depth of the ion beam into the substrate is large. , The adhesion of the thin film to the substrate is greatly improved.

〔Example〕

 Next, examples of the present invention will be described.

FIG. 1 is a schematic system diagram showing the configuration of an embodiment of an apparatus for carrying out the present invention. In FIG. 1, a vacuum container 1
Inside, a substrate holder 2 for mounting and rotating the substrate 3 is provided. The vacuum container 1 includes a substrate 3 inside the container.
An ion source 5 for implanting the ion beam 4 is provided in the. Further, an electron beam vapor deposition device 7 for forming a vapor deposition film on the surface of the substrate 3 is provided in the vacuum container 1.

The vacuum container 1 is provided with a vacuum pump 6 for creating a vacuum inside the container. Cooling water is circulated in the substrate holder 2.

Next, the operation of this embodiment will be described.

The substrate 3 is, for example, an aluminum silicon alloy disc having a diameter of 90 mm. The substrate 3 is irradiated with the nitrogen ion beam 4 accelerated at 20 kV for 3 minutes, and the surface of the substrate 3 is cleaned by the sputtering action. After that, for example, titanium is vapor-deposited by the electron beam vapor deposition device 3, and at the same time, the nitrogen ion beam 4 is injected into the surface of the substrate 3.

The current density of the nitrogen ion beam 4 is changed while the acceleration voltage of the ion beam is kept constant at 20 kV. At the same time, by changing the output of the electron gun of the electron beam vapor deposition device 7, the vapor deposition rate of titanium is changed.

The thickness of the thin film was kept constant at 0.5 μm, and the current density of the nitrogen ion beam and the amount of impurities such as oxygen or carbon when the deposition rate of titanium was changed were measured. Regarding the measurement of the amount of impurities, after removing the surface layer to 0.2 μm so as not to be influenced by the surface by Auger electron spectroscopy, the amount of impurities of oxygen and carbon was measured by the intensity ratio of the spectrum. The results are shown in FIG. As can be seen from FIG. 2, the amount of impurities is larger in oxygen than in carbon. By setting the vapor deposition rate on the thin film surface to 3Å / sec or more and the nitrogen ion beam current density on the thin film surface to 0.3 mA / cm ² or more, the amount of oxygen impurities can be made 10% or less. At the same time, carbon impurities can be reduced to approximately 5% or less.

In the conventional thin film manufacturing method by so-called dynamic mixing, the concentration of oxygen in the thin film is 30% in terms of atomic concentration.
It was included above. Therefore, according to the thin film manufacturing method of the present embodiment, the amount of oxygen impurities can be reduced to 1/3 or less of the conventional amount. This also applies to other impurities such as carbon. The present inventor has confirmed that when the amount of impurities is reduced to 1/3 or less of the conventional amount, the characteristics of the thin film, such as peeling resistance and strength, are significantly improved.

In this embodiment, a normal oil diffusion pump was used as the vacuum pump, and no trap of liquid nitrogen was used. Moreover, the conditions of use were such that the degree of vacuum was 5 × 10 ⁻⁶ Torr or less, which is the range of use of a normal oil diffusion pump. Even if the degree of vacuum is low, by setting the ion current density of ion implantation to 0.3 mA / cm ² or more and the deposition rate to 3 Å / sec or more, the implanted ions that reach the surface of the substrate per unit time The amount with the particles can be made significantly larger than the arrival amount of impurities such as carbon and oxygen from the vacuum container. Therefore, the amount of impurities in the thin film can be significantly reduced rapidly and reliably without using an expensive turbo pump or the like.

〔The invention's effect〕

According to the method of manufacturing a thin film of the present invention, ion implantation is performed so that the ion current density on the surface of the thin film is 0.3 mA / cm ² or more, and vapor deposition of vapor deposition particles on the surface of the thin film is 3Å / sec. By performing as described above, the amount of impurities mixed in the thin film can be significantly reduced.

Further, since the ion implantation is performed with an ion energy of more than 10 keV, the depth of penetration of the ion beam into the substrate is large, and the adhesion of the thin film to the substrate is greatly improved.

As a result, a thin film excellent in various properties such as peel resistance and strength can be manufactured on the substrate.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of an embodiment of a thin film forming apparatus for carrying out the thin film forming method according to the present invention, and FIG. 2 is a change in vapor deposition rate and ion beam current density, and impurity atoms contained in the thin film. It is a graph which shows the relationship with a density. 1 ... Vacuum container, 2 ... Substrate holder, 3 ... Substrate, 4
Ion beam, 5 ion source, 6 vacuum pump, 7 electron beam evaporation system.

Claims (1)

[Claims] 1. A method of manufacturing a thin film, wherein a thin film is formed on a substrate surface by simultaneously performing ion implantation and vapor deposition, wherein the ion implantation is performed at an ion energy of more than 10 keV and an ion current density on the thin film surface is 0.3 mA / performs so that the cm ² or more, the deposition is the deposition rate of the vapor deposition particles on the surface of the thin film 3 Å / sec
A method for producing a thin film, which is performed as described above.