JPS60234965A - Manufacture of thin film - Google Patents

Abstract

PURPOSE:To form a thin film having excellent peeling resistance by forming the thin film whose composition is slowly changed on the surface of material to be coated through controlling the partial pressure of reaction gas and thereby making a desired comp. of the surface of the thin layer. CONSTITUTION:The inside of a vacuum vessel 31 is made required degree of vacuum with a vacuum pump 36 and gaseous Ar is introduced therein from a bomb 40 by opening a cock 39. DC voltage is impressed between a valve body 8 and an evaporation source 34 to cause glow discharge and Zr is evaporated, ionized and plated on the surface of the valve body 8 to form the region I. Then, oxygen is slowly introduced into the vacuum vessel 31 from a bomb 38 by opening a cock 37 and the transition region III showed by ZrO2-X is began to be made on the region I. The control is performed so that the partial pressure of the reaction gas in the inside of the vacuum vessel 31 is slowly elevated according to the elapse of time and the insulating region II consisting of ZrO2 is formed with prescribed thickness on the transition region III.

Description

[Detailed description of the invention] Industrial application field: Thick QBJ1 is used to deposit and form a thin film on the surface of a desired object by physical or chemical vapor deposition methods such as ion derating, sulfur 4 phthaling, CVD, etc. The present invention relates to a method for manufacturing a thin film.

BACKGROUND OF THE INVENTION It is often required to form thin film layers, such as thin film insulating layers, on the surface of metals, and conventional methods for producing such thin film layers include coating metal-gas compound films by reactive coating means. A method for forming a metal surface on a metal surface is disclosed in JP-A-58-221271. but,
In this disclosed method, it is difficult to maintain good adhesion between the base metal and the produced thin film, and the produced thin film is damaged by stress or mechanical external force caused by the difference in coefficient of thermal expansion. It has the problem of being easy to peel off.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide a method for producing a thin film that can form a conductive or insulating thin film on the surface of a metal or other material in an adhesive manner.

Structure of the Invention According to the present invention, in a thin film manufacturing method in which a thin film is provided on the surface of a desired material to be coated by a vapor deposition method, the vapor of a desired metal reacts with the metal to form a desired compound. The gas to be coated is at least partially ionized in a reaction chamber in which the material to be coated is placed, and the ionized metal or the compound of the metal and the gas is coated by a predetermined potential applied to the material to be coated. When depositing on the material, the partial pressure of the gas is controlled so that the ratio of the partial pressure of the metal vapor to the partial pressure of the gas gradually changes, thereby gradually changing the composition of the thin film along the film thickness direction. It is characterized by the fact that it changes.

When the material to be coated is a metal, the partial pressure of the gas is first reduced to zero to form a metal layer on the surface of the material to be coated, and then the partial pressure of the gas is gradually increased to separate the metal vapor and the gas. The gas is heated to a pressure sufficient to form a non-stoichiometric compound region formed by combination with the metal and the gas, and ultimately the desired compound obtained by the combination of the metal and the gas. Increase pressure. With this, the surface area of the material to be coated is made of metal, but the outer surface is made of the required metal compound, and between them there is a thin film that is an intermediate layer determined by the magnitude of the partial pressure of the gas. can do.

If this required metal compound is selected to be insulating, for example, an insulating layer can be formed on the metal material.

On the other hand, the present invention can also be used when forming a metal thin film on the surface of a material to be coated made of the same material as the above-mentioned metal compound. In this case, the partial pressure of the gas is increased at the start of thin film formation (so that the required metal compound is formed), and then the partial pressure of the gas is gradually decreased to reduce the surface layer of the thin film being formed. It can be made of metal.

This thin film consists of ionized metals such as Zr, Cr, AL, etc. evaporated from the evaporation source and a reactant gas, such as 0□.

N2. When a compound such as C2H2 is applied to the surface of a material to be coated by a vapor deposition method (for example, an ion blating method) while reacting, the concentration of the reaction gas is adjusted so as to gradually increase or decrease the concentration of the reaction gas. This can be easily obtained through control.

For example, select Zy as the evaporative substance and 0 as the reaction gas.
When selecting option 2, when forming a thin film, the inside of the container is first evacuated, and then Zr is deposited on the surface of the material to be coated using the ion silating method in an atmosphere containing only Zr ions to form a metal layer. After that, the concentration of 02 is increased at a predetermined ratio over time, and zrO□□
Further, a thin film is formed in the state of a non-stoichiometric compound,
Finally, the area near the surface of the thin film is defined as Z r O2. As a result, the obtained thin film has a characteristic that the oxygen content increases along the film thickness direction from the inside to the outside. in this way,
The inside of the thin film is in a low oxygen content state with good adhesion to the metal or is the metal itself, and the metal layer portion (Zr layer portion) of the thin film is adhered to the surface of the metal to be coated. The adhesion between the thin film and the material to be coated is extremely good. On the other hand, since the outer surface of the thin film is a hard insulating material, the thin film can sufficiently maintain the desired electrical insulation and form a thin film with extremely excellent wear resistance and peeling resistance. be able to.

This thin film can be manufactured using conventional vapor deposition methods, except for adjusting the concentration of the reactant gas, and exhibits excellent properties such as being easy to manufacture, robust, and durable.Example: Figure 1 2 shows a partially cross-sectional view of an embodiment of a fuel injection valve with a switch, in which an on-off switch is configured by a valve body and a valve seat. It is shown. A fuel injection valve 1 for an internal combustion engine is
Comprising a nozzle holder 2, an intermediate plate 3 and a nozzle 4,
All of these are screwed into the retainer 5. Nozzle 4 has nozzle D6 and nozzle D6
A nine-needle valve 8 is slidably provided in a guide hole 7 formed therein.
It consists of. A conical body 9 serving as a valve body is formed at the tip of the needle valve 8, and a valve seat υ formed in a shape corresponding to this conical body 9 is formed on the nozzle body 6. An oil sump 11 formed above the valve seat 10 communicates with a fuel passage 12. A pressure bottle 13 provided at the upper end of the needle valve 8 is in contact with a spring receiver 14 when the injection valve is inactive.

A pressurized coil spring 1 is placed in the spring chamber 15 in the nozzle holder 2.
One end of this coil spring 16 is supported by the shoulder 20 of the spring chamber 15 via the lower end disk portion 19 of the electrode 18 fitted in the insulating sleeve 17.
The other end is supported by a spring receiver 141C. The insulating sleeve 17 is for maintaining electrical insulation between the lightning pole 18 and the nozzle holder 2 made of a conductive material, and may be press-fitted into the hole 21 of the nozzle holder 2.
It may be inserted into the hole 21 in a loosely fitted state. code 22
．． Reference numeral 23 indicates an O-ring for maintaining a liquid-tight state.

The pressure coil spring 16, the pressure bottle 13, the spring receiver 14, and the needle valve 8 are made of steel, which is a conductive material.
Therefore, the electrode 18 and the needle valve 8 are electrically conductive via the pressure bottle 13, the spring receiver 14, and the pressure coil spring 16. Note that the reference numeral 24 indicates the pressure coil spring 16.
This is an insulating sleeve to prevent electrical contact between the nozzle holder 2 and the nozzle holder 2. This is especially necessary in small fuel injection valves because the space between the pressurizing coil spring 16 and the wall of the spring chamber 15 is narrow. . On the other hand, the nozzle body 6, intermediate plate 3, retaining nut 5 and nozzle holder 2 are also all made of a conductive material such as steel.

In order to maintain electrical insulation between the outer circumferential surface of the large diameter part of the needle valve 8 and the inner circumferential surface of the guide hole 7 of the nozzle body 6, the outer circumferential surface of the needle valve 8 is coated with an insulating layer by the method of the present invention. A thin film 26 is provided to be formed.

In this embodiment, the area near the surface of the thin film 26 is made of zirconium oxide (Zr0z), but its internal state is such that the oxygen amount θ in the thin film 26 decreases as it approaches the surface of the valve body 8. The surface has a cross-sectional structure consisting of only Zr. That is, as shown in FIG. 2, in the region I from 1=0 to 1=11, which is the surface of the valve body 8,
The composition of No. 6 is a metal layer consisting only of Zr, and the composition is from 1 = 1° which is the outer surface of the thin film 26 to 1 = 1. In the region (2) up to (2), the composition of the thin film 26 is insulating Z r O2. In the transition region of 1, <1<1 m, the composition of the thin film 26 is a non-stoichiometric compound region of Z ro 2□. As a result, the degree of insulation of the portion made of the compound of the required metal and reactive gas increases continuously from the surface side of the valve body 8 toward the wall side of the guide hole 7.

When the thin film 26 has a structure as shown in FIG. 2, the metal layer region I adheres to the metal valve body 8 with very strong adhesion, and the region It is possible to ensure insulation between the two and also ensure wear resistance. Then, in transition region ■, region 1 has different properties.
．． Since If can be firmly bonded, it is possible to form a thin film 26 that is highly resistant to peeling and abrasion, and a fuel injection valve with a switch having excellent durability can be constructed. Furthermore, the coefficient of thermal expansion of the transition region (2) is the same as that of the region (1).
Since the value is intermediate between (2) and the value gradually changes along the thickness direction, it has the advantage that the peeling resistance of the thin film against heat shrinkage and scratches that occur during heating is also good.

Next, a thin film 26 having a cross-sectional structure as shown in FIG.
A specific method for forming the surface of the valve body 8 will be explained with reference to FIG.

The valve body 8 disposed inside the vacuum container 31 is connected to the negative electrode of the DC high pressure source 32, and the evaporation source 34 provided on the partition plate 33 inside the vacuum container 31 is connected to the positive electrode of the DC high pressure source 32. has been done. Zr is placed in the evaporation source 34, and the Zr in the evaporation source 34 is melted and evaporated by electrons from the electron gun 35. The inside of the vacuum container 31 is evacuated by a vacuum pump 36 to maintain a required degree of vacuum.

When the inside of the vacuum container 31 reaches a required degree of vacuum, the cock 39 is opened to introduce Ar gas from the I-type impeller 40, and a DC voltage is applied between the valve body 8 and the evaporation source 34 to generate a glow discharge. After cleaning the inside of the container, the Zr is evaporated, and the ionized Zr is brated onto the surface of the valve body 8 by the negative high pressure applied to the valve body 8 at this time.
As a result, region (2) is formed. Although not shown, a high frequency method or a thermionic method is performed to promote the ionization of Zr.

When the thickness of the area ■ reaches a predetermined value, the cock 37
is opened, and oxygen, which is a reactive gas, is allowed to gradually flow into the vacuum container 31 from the cylinder 38.

As a result, a transition region (2) indicated by ZrO2-X begins to be formed on the region I. Control is performed so that the partial pressure of the reaction gas in the vacuum container 31 gradually increases as time passes, and a transition region (2) having an oxygen content gradient shown in FIG. 2 is formed. Finally, a state is reached in which ZrO2 is generated, and an insulating region (2) made of ZrO7 is formed to a predetermined thickness on the transition region (2).

In this way, the thin film 26 having the structure shown in FIG. 2 can be easily formed by simply controlling the partial pressure of the reaction gas using the conventional ion silating method.

In the above embodiment, Zr was used as the evaporation substance and O2 was used as the reaction gas, but the material of the thin film is not limited to these, and other inorganic insulating materials can be used. Therefore, as evaporated substances, AZ + Cr + S
i, etc., while N2. C2H2 etc. can be used, but in any case, the evaporating substance and the metal of the material to be coated do not have any intermetallic compound whose properties change suddenly, and the metal being the evaporating substance and the metal being the evaporating substance It is also required that there be no sudden change in physical properties between the reactant and the compound produced by the reaction gas.

When the adhesion layer is formed by such an ion silating method, the temperature during the treatment is low (550° C. or less), so material distortion occurs in the valve body 8 which has already been heat treated.
It has the excellent advantage that there is no need to perform tempering or tempering, and there is no need to worry about pollution because it is a dry system in a closed container.

In the above embodiment, a thin film is formed on the surface of a metal, and the surface portion is used as an insulating layer. However, the thin film manufacturing method according to the present invention is not limited to the above embodiment; The present invention can be similarly applied to the case where the metal of the evaporated substance is deposited on the surface of a material consisting of a compound produced by It is.

Further, in the above embodiment, a configuration is shown in which the metal gas is supplied from the evaporation source 34 disposed inside the vacuum vessel 31, but the required metal gas is supplied from outside the vacuum vessel 31 to the vacuum vessel 3.
1 may be introduced.

In addition, as a vapor deposition method, physical and chemical vapor deposition methods such as a sputtering method and a CVD method can be used in addition to the ion blasting method.

Effects of the Invention According to the manufacturing method of the present invention, as described above, by controlling the partial pressure of the reaction gas, a thin film whose composition gradually changes is formed on the surface of the desired material to be coated. Since the surface of the thin film is made of the required compound, the part of the thin film in contact with the surface of the temporary coating material has a composition that adheres well to the material to be coated, and the middle part of the thin film can be made of a non-stoichiometric compound. , it is possible to form a thin film that has extremely high peeling resistance against thermal shock.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a fuel injection valve in which an insulating film of the valve body is provided by the manufacturing method of the present invention, and FIG. 2 is a compositional structure of the thin film on the surface of the valve body shown in FIG. FIG. 3 is a block diagram of an ion silating apparatus for forming the thin film shown in FIG. 1. 8... Needle valve, 26... Thin film, 31... Vacuum container,
32... DC high pressure source, 34... Evaporation source, 35...
Electron gun, 36...vacuum pump. Patent applicant: Diesel Kiki Co., Ltd. Agent: Patent attorney: Masatoshi Takano Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a thin film manufacturing method in which a thin film is provided on the surface of a desired material to be coated by vapor deposition, the material to be coated is exposed to a vapor of the desired metal and a gas that reacts with the nuclear metal to form a desired compound. Applying the metal or a compound of the metal and the gas to the material to be coated, which is at least partially ionized in a reaction chamber in which the material is located, and which is ionized by a predetermined potential applied to the material to be coated. During the process, the partial pressure of the gas is controlled so that the ratio of the partial pressure of the metal vapor to the partial pressure of the gas gradually changes, and the composition of the thin film is gradually changed along the film thickness direction. A thin film manufacturing method characterized by: