JPH04333574A - Coating film and its production - Google Patents

Abstract

PURPOSE:To improve the adhesion of a coating film to a substrate by providing a base film consisting of a substrate constituent element with the density decreasing from the substrate toward the film and a film constituent element between the substrate and the coating. CONSTITUTION:A vacuum vessel is evacuated to a specified vacuum, then a material 12 contg. a substrate constituent element is vaporized from a vaporization source 10, and a material 14 contg. a film constituent element is vaporized from a vaporization source 14. At this time, the amt. of the material 12 to be vaporized from the source 10 is continuously or intermittently decreased to form a base film 4 with the substrate constituent element decreasing from the substrate 2 toward a coating film 6, and then the coating film 6 is vapor- deposited. After the base film 4 is formed, simultaneously or alternately with the vapor-deposition an accelerated ion 22 is drawn out of an ion source 20, and the ratio of the number of the vaporized atoms reaching the substrate 2 to that of the ions is adjusted by a film thickness monitor 18 and an ion current monitor 24. The crystallinity, adhesion, stability, etc., of the film 6 are improved in this way.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane-coated article in which a membrane is formed on the surface of a substrate, and a method for producing the same.

0002

2. Description of the Related Art Membrane coatings, in which a film is formed on the surface of a substrate, have been conventionally produced for various purposes, such as increasing the abrasion resistance of the substrate or increasing the thermal conductivity of the substrate.

[0003] Formation of such a film is performed by a PVD method (physical vapor deposition method) or a CVD method (chemical vapor deposition method). Generally speaking, the CVD method has the advantage of excellent adhesion between the substrate and the film because the film is formed at a high substrate temperature, but only the substrate can withstand the film formation temperature. It has the disadvantage that it cannot be used. On the other hand, although the PVD method can form a film at a lower temperature than the CVD method, it has the disadvantage that the adhesion of the film is inferior to that of the CVD method.

[0004] Therefore, in recent years, CV technology, which can actively utilize plasma and ion irradiation to produce films at relatively low temperatures, has been developed.
Various attempts have been made to use the D method and the PVD method that can improve film adhesion.

[0005]

[Problems to be Solved by the Invention] However, despite the above-mentioned attempts, conventional film coatings have the desired film directly formed on the surface of the substrate; Poor adhesion of the film due to poor compatibility (compatibility); Differences in lattice constants, coefficients of thermal expansion, etc. between the substrate and the film may impede crystal growth of the film or induce internal stress in the film. Therefore, there are problems such as poor adhesion, stability, and crystallinity of the film.

Accordingly, the present invention provides a membrane coating and a method for manufacturing the same, which improve the wettability of the target membrane to the substrate and alleviate the difference in lattice constant, thermal expansion coefficient, etc. between the membrane and the substrate. The main purpose is to provide

[0007]

[Means for Solving the Problems] In order to achieve the above object, the film coating of the present invention comprises a base film consisting of a base constituent element and a film constituent element between the base body and the film as described above. , is characterized in that the density of the base constituent elements within the base film is distributed such that it decreases from the base side toward the surface of the base film.

[0008] Furthermore, in the manufacturing method of the present invention, when forming a film on the surface of a substrate to produce a film-coated article, first, the substrate constituent elements and the film constituent elements are vapor-deposited and ion irradiated on the surface of the substrate. The method is characterized in that a base film is formed, and this vapor deposition is performed while reducing the amount of the base constituent element to be deposited, and then the film is formed on the surface of the base film.

[0009]

[Function] In the above-mentioned membrane coating, the presence of the underlayer film having a changed composition as described above alleviates the difference in lattice constant, thermal expansion coefficient, etc. between the target film and the substrate. As a result, the crystallinity, adhesion, stability, etc. of the target film are improved. In addition, common elements exist near the interfaces of the substrate, base film, and target film, so
The wettability of these films is improved, and this also improves the adhesion between the film and the substrate.

Further, according to the above manufacturing method, it is possible to easily form a base film having a changed composition as described above on the surface of the substrate, and the pushing action of the irradiated ions causes the base film to be formed near the interface between the base film and the base body. A mixed layer containing the constituent elements of both is formed, and this acts like a wedge, further improving the adhesion of the base film to the substrate, thereby achieving the desired bond between the film and the substrate as a whole. Adhesion is further improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic sectional view showing an example of a membrane coating according to the present invention.

This film coating does not directly form the desired film 6 on the surface of the substrate 2 as in the conventional method, but instead forms a film between the two, consisting of the elements constituting the substrate 2 and the elements constituting the film 6. A base film 4 consisting of the following is interposed. Moreover, the density of the base material constituent elements within this base film 4 is distributed so as to decrease continuously or intermittently from the base body 2 side toward the surface of the base film 4. In other words, the density of the elements constituting the film 6 in the base film 4 is distributed so as to increase toward the surface of the base film 4.

The type of substrate 2 is not limited to a specific one, and may be, for example, various metals, ceramics, glass, or other materials.

Furthermore, the type of film 6 is not limited to a specific one, and may be, for example, a nitride film such as BN or TiN, a diamond-containing carbon film, or even other films.

In such a film coating, the difference in lattice constant between the target film 6 and the substrate 2 is alleviated by the presence of the base film 4 whose composition has changed as described above, so that the film The crystallinity of No. 6 is improved. Further, since the base film 4 having the same structure can be formed under the target film 6, it is also possible to control the crystal structure of the target film 6.

Furthermore, the presence of the base film 4 alleviates the difference in thermal expansion coefficient between the target film 6 and the substrate 2, thereby reducing the internal stress of the film 6 and improving the adhesion of the film 6. This also improves the stability of the film 6 and the like.

[0017] Furthermore, since a common element is present near each interface of the substrate 2, base film 4, and target film 6, the wettability of these films 4 and 6 is improved, and therefore, from this point of view, Adhesion between the film 6 and the base 2 is improved.

Next, an example of a method for manufacturing the membrane coating as described above will be explained with reference to FIG.

A holder 8 for holding the substrate 2 is provided in a vacuum container (not shown), and two evaporation sources 10 and 14 and an ion source 20 are arranged facing it. Further, in this example, a film thickness monitor 18 and an ion current monitor 24 are arranged near the holder 8 for measurement and control.

The evaporation source 10 can evaporate the substance 12 containing the constituent elements of the substrate 2, and the evaporation source 14 can evaporate the substance 16 containing the constituent elements of the target film 6 as described above. can. However, these two substances12
, 16, as in this example a separate evaporation source 10,
14, or both substances 12 and 16 may be evaporated by scanning the two evaporation materials with a heating electron beam using the same evaporation source. A mixture of 12 and 16 may be evaporated. Further, the method of the evaporation source is not limited to a specific method, and may be, for example, one that heats the evaporation material using an electron beam or high frequency, or one that sputters a target.

The ion source 20 may be of any type as long as it can accelerate and extract the ions 22 from it. For example, a multi-pole magnetic field type so-called bucket-type ion source is preferable in terms of large area and large current, but other ion sources may of course be used. Aeon 22 to be drawn from this
The type may be selected depending on the type of base film 4 to be formed on the substrate 2, etc. For example, when forming a nitride film such as BN or TiN, use nitrogen ions or a mixture of nitrogen ions and inert gas ions, and when forming a non-compound film such as a carbon film, select inert gas ions. .

Further, the acceleration energy of the ions 22 is not particularly limited, but it is preferably about 40 KeV or less in order to reduce damage such as defects in the base film 4 due to the irradiation.

In manufacturing the membrane coating shown in FIG. 1, first, the desired substrate 2 is attached to the holder 8, the inside of the vacuum container is evacuated to a predetermined degree of vacuum, and then the evaporation source 10 is evacuated as described above. At the same time, the substance 12 containing the substrate constituent elements is evaporated, and the substance 14 containing the above-mentioned film constituent elements is evaporated from the evaporation source 14, and these are deposited on the surface of the substrate 2. As a result, a base film 4 consisting of the elements constituting the target film 6 and the elements constituting the base body 2 begins to be formed on the surface of the base body 2 . While performing such evaporation, the substance 1 containing the base constituent elements from the evaporation source 10 is
2. Continuously or intermittently decreases the amount of evaporation.

Simultaneously or alternately with the above vapor deposition, or after the formation of the base film 4, accelerated ions 22 are extracted from the ion source 20 and irradiated toward the substrate 2. At this time, the ratio of the number of evaporated atoms to the number of ions reaching the substrate 2 can be adjusted using the film thickness monitor 18 and the ion current monitor 24. The reason why the ions 22 may be irradiated after the formation of the base film 4 is that if the energy is appropriately selected, the ions can be implanted to a desired depth.

[0025] As a result, the composition of the surface of the substrate 2 has changed as described above (that is, the density of the constituent elements of the substrate decreases continuously or intermittently from the side of the substrate 2 toward the surface of the base film 4). A base film 4 is formed (distributed over the entire surface area). Moreover, due to the pushing action of the irradiated ions 22, a mixed layer containing constituent elements 4 and 12 is formed near the interface between the base film 4 and the substrate 2, and this acts like a wedge. The adhesion of the base film 4 is significantly improved.

Thereafter, a desired film 6 (see FIG. 1) is formed on the surface of the base film 4 formed in the above steps. The method for forming this film 6 may be a CVD method or a PVD method, and is not limited to a specific method.

[0027] Through the above steps, a membrane coating as explained in FIG. 1 can be made.

Next, more specific examples according to the present invention and some comparative examples corresponding to conventional examples will be described.

Example 1 When forming a boron nitride film on a stainless steel (SUS304) substrate using the ion beam sputtering method, a film made of boron and iron was first formed on the substrate by the IVD method (a method that uses both vapor deposition and ion irradiation). A base film was formed. Specifically, this was carried out by vacuum evaporating boron (purity 2N) and iron (purity 3N) onto a substrate and simultaneously irradiating argon ions. The thickness of this base film is 2000 Å, the ion acceleration energy is 10 KeV, and at the beginning of film formation, the ratio of the number of boron atoms reaching the substrate + the number of iron atoms and ions (that is, (B + Fe ) / ions (hereinafter the same) is 10, and the number ratio of iron atoms to ions (i.e. F
e/ion. (same below) was 5, but as the thickness of the base film to be formed increased, the amount of evaporation of iron atoms was reduced, and in the final film formation of 200 Å, only boron was evaporated and ions were irradiated. . Thereafter, a boron nitride film was formed on this base film by ion beam sputtering. At that time, a boron nitride sintered body (purity 2N) was used as the sputtering target, and argon ions were used as the ions.
The acceleration energy of this ion was set to 1 KeV, and a film thickness of 1 μm was formed.

Comparative Example 1 Using the same substrate as in Example 1, a boron nitride film was directly formed on it by ion beam sputtering without forming a base film. At that time, a boron nitride sintered body (purity 2N) was used as a sputtering target, argon ions were used as ions, the acceleration energy of the ions was set at 1 KeV, and a film thickness of 1 μm was formed.

Comparison of the adhesion of boron nitride films between Evaluation Example 1 and Comparative Example 1 (scratch test was used to evaluate the adhesion of the films;
(Evaluated at critical load at which the membrane peels off), Example 1 was 3
0N, and that of Comparative Example 1 was 5N. That is, it can be seen that the adhesiveness of the intended boron nitride film is significantly improved in the example. In addition, Example 1 and Comparative Example 1
When comparing the crystal structure of the boron nitride film with (the film structure was evaluated using X-ray diffraction method), it was found that in Example 1, boron nitride (c- BN) was detected, whereas in Comparative Example 1, only hexagonal boron nitride (h-BN) was detected. Therefore, when we measured the Vickers hardness of this film under a 10g load, it was approximately 4000 for Example 1 and approximately 2 for Comparative Example 1.
It was 500. That is, it can be seen that the crystallinity of the intended boron nitride film is improved in the example.

Example 2 Ti was deposited on stainless steel (SUS304) by IVD method.
When forming a ternary film made of -BN, a base film made of boron and iron was first formed by the same IVD method. This was done by simultaneously vacuum depositing boron (2N purity) and iron (3N purity) onto the substrate and irradiating it with nitrogen ions. The thickness of this base film is 2000 Å, the ion acceleration energy is 10 KeV, and at the beginning of film formation, the ratio of the number of boron atoms reaching the substrate + the number of iron atoms to the number of ions is 10, and The number ratio of iron atoms to ions was 5, but as the thickness of the base film to be formed increased, the amount of iron atoms evaporated was reduced, and in the final film formation of 200 Å, only boron evaporated and ions were evaporated. Irradiation was performed. Thereafter, a Ti-B-N film was formed on this base film by the IVD method. At that time, Ti (purity 4N) and boron (purity 2N) were simultaneously deposited on the base film, and at the same time, nitrogen ions were irradiated. The acceleration energy of this ion is 1K
eV, the atomic ratio of Ti to boron reaching the substrate (Ti 2 /B) was 2, and the ratio of the number of Ti atoms reaching the substrate to the number of ions (Ti 2 /ion) was 1. The film thickness was 1 μm.

Comparative Example 2 A Ti-B-N film was directly formed on the same substrate as in Example 2 by the IVD method without forming a base film. At that time, T
i (purity: 4N) and boron (purity: 2N) were simultaneously deposited onto the substrate, and at the same time nitrogen ions were irradiated. The acceleration energy of this ion was set to 1 KeV, the atomic ratio of Ti to boron reaching the substrate was 2, and the ratio of the number of Ti atoms reaching the substrate to the number of ions was 1. The film thickness was 1 μm.

Comparing the adhesion of the Ti-B-N films in Evaluation Example 2 and Comparative Example 2 (a scratch test was used to evaluate the adhesion of the film, and the evaluation was performed using the critical load at which the film peels off). The strength of Example 2 was 30N, while that of Comparative Example 2 was 15N. From this, it can be seen that the adhesiveness of the intended film is higher in the example.

[0035]

Effects of the Invention As described above, in the film coating of the present invention, due to the presence of the underlying film with a changed composition as described above, the difference in lattice constant and thermal expansion coefficient between the target film and the substrate can be reduced. The difference between the two will be alleviated. As a result, the crystallinity, adhesion, stability, etc. of the target film are improved. In addition, common elements exist near the interfaces of the substrate, base film, and target film, so the wettability of these films is improved, and this also improves the adhesion between the film and the substrate. do.

Furthermore, according to the manufacturing method of the present invention, it is possible to easily form a base film with a changed composition as described above on the surface of the substrate, and the push-in action of the irradiated ions also allows the base film to bond with the base film. A mixed layer containing the constituent elements of both is formed near the interface, and this acts like a wedge, further improving the adhesion of the base film to the substrate, thereby making it possible to achieve the desired film as a whole. Adhesion to the substrate is further improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a membrane coating according to the present invention.

FIG. 2 is a schematic diagram showing an example of an apparatus for carrying out the manufacturing method according to the present invention.

[Explanation of symbols]

2 Base 4 Base film 6 Target membrane 10,14 Evaporation source 12 Substances containing base constituent elements 16 Substances containing film constituent elements 20 Ion source 22 Ion

Claims (2)

[Claims] 1. In a film coating in which a film is formed on the surface of a substrate, between the substrate and the film, there is provided a base film consisting of a substrate constituent element and a film constituent element, the density of the base constituent element being within the base film. 1. A membrane coating, characterized in that the membrane coating is provided with a distribution that decreases from the substrate side toward the surface of the base membrane. 2. When forming a film on the surface of a substrate to produce a film coating, first, vapor deposition and ion irradiation of the substrate constituent elements and the film constituent elements are performed on the surface of the substrate to form a base film;
Moreover, the method for producing a film coating is characterized in that the vapor deposition is performed while reducing the amount of the base constituent element vaporized, and then the film is formed on the surface of the base film.