JPS6222314A - Manufacture of thin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a thin film for forming an insulating thin film on the surface of a required member by a physical vapor deposition method such as an ion silating method or a silting method. This relates to a manufacturing method.

(Prior Art) It is often required to form a thin film layer, such as a thin insulating layer, on the surface of a metal. Conventional methods for producing such a thin film layer include forming a metal-gas compound film into a reactive material. A method for forming metal surfaces by means of coating is disclosed in British Publication No. 2,123,441.

(Problems to be Solved by the Invention) However, in this disclosed method, it is difficult to maintain good adhesion between the base metal and the produced thin film.

That is, the thin film is likely to peel off due to stress or mechanical external force acting between the base material and the adhered thin film due to the difference in coefficient of thermal expansion.

Generally, when forming a thin film by a physical vapor deposition method such as the ion grating method, the collision energy of ions on the adherend is increased by increasing the voltage applied to the base material on which the thin film is to be formed. It is said that the adhesion between the material and the base material increases. However, when depositing an insulating thin film, if the applied voltage is increased, a high-quality insulating film cannot be formed due to dielectric breakdown on the surface of the base material. It was difficult to form it on the required base material with good adhesion.

An object of the present invention is to provide a thin film manufacturing method that can form an insulating thin film with excellent peeling resistance on the surface of a base material.

(Means for Solving the Problems) To achieve the above object, the present invention provides a thin film manufacturing method in which an insulating thin film is provided on the surface of a required member to be coated by physical vapor deposition. , in a reaction chamber in which the member to be coated is placed, the ionized vapor of a predetermined metal is reacted with a predetermined reaction gas that reacts with the metal to form a predetermined insulating compound, and the partial pressure of the vapor of the metal is reduced. and the partial pressure of the reaction gas is gradually changed during the reaction, and the ionized substance in the reaction chamber is deposited on the member to be coated by a vapor deposition method,
The present invention is characterized in that the magnitude of the voltage applied to the member to be coated is reduced as the insulating compound is formed.

(Function) When a required metal vapor and a gas that reacts with the metal to form a required insulating compound are introduced into the reaction chamber, at least a portion of the metal vapor is ionized by a predetermined ionization means. A material having good adhesion to the member to be coated is selected as the metal, and a metal layer is first formed on the surface of the member to be coated by first reducing the partial pressure of the reaction gas to zero. In this case, the voltage applied to the member to be coated is set relatively high, the metal ions collide with the surface of the member to be coated with high energy, and a metal layer is formed on the surface of the member to be coated with high adhesion. In this case, an ion implantation effect can also be expected by applying a high voltage. □Then, the partial pressure of the reaction gas is gradually increased, and a non-stoichiometric compound generated by the metal vapor and the reaction gas is formed on the metal layer formed as a base treatment as described above, and the final In this step, the partial pressure of the reactant gas is increased to a pressure sufficient to produce the desired insulating compound resulting from the combination of the metal and the reactant gas. At the same time as the partial pressure of the reactant gas is increased, the level of the voltage applied to the member to be coated is gradually lowered, whereby the insulating compound is deposited on the member to be coated via the metal layer at a low voltage.

As a result, the metal layer for base treatment is firmly adhered to the member to be coated using a high voltage, and the required insulating compound is applied to this metal layer via the non-stoichiometric compound layer with a relatively low voltage. Formed in polymorphism. Therefore, an insulating thin film can be formed while maintaining the adhesion of the insulating compound to the member to be coated and without degrading the quality of the insulating compound.

(Example) FIG. 1 shows a valve body insulating film of a fuel injection valve configured with an on-off switch that is turned on when the valve body is seated on a corresponding valve seat, which is formed by the manufacturing method of the present invention. A partial cross-sectional view showing an embodiment of a fuel injection valve is shown. The fuel injection valve 1 includes a nozzle holder 2, a grate member 3, and a nozzle 4.
, all of which are screwed into the sleeve nut 5.

The nozzle 4 consists of a nozzle holder 6 and a needle valve 8 which is slidably received and guided in a guide hole 7 formed in the nozzle medium 6. - A conical body 9 that functions as a valve body is formed at the tip of the needle valve 8, and a valve seat 10 formed in a shape corresponding to this conical body 9 is formed on the nozzle body 6. An oil reservoir 11 formed above the valve seat 10 communicates with a fuel passage 12.

The needle valve 8 is made of steel, and when the fuel injection valve 1 is in the closed state, the needle valve 8 is electrically connected via a conductive pin 13 to a conductive spring receiver 14 .

A pressurized coil spring 1 is placed in the spring chamber 15 in the nozzle holder 2.
6 is housed, and this coil spring 16 is connected to the lower end disk portion 1 of the electrode 18 fitted in the insulating sleeve 17 on the one hand.
9 on the shoulder 20 of the spring chamber 15 and, on the other hand, on the spring receiver 14 .

The insulating sleeve 17 is for maintaining electrical insulation between the nozzle holder 2 made of a conductive material and the electrode 18, and may be press-fitted into the hole 21 of the nozzle holder 2, or may be press-fitted into the hole 21. It may be inserted in a loosely fitted state. code 2
2.23 is an O-ring to maintain an oil-tight condition.

The pressure coil spring 16 is also made of a suitable electrically conductive material, such as steel, so that the electrode 18 and the needle valve 8 are electrically conductive through the pin 13, the spring receiver 14, and the coil spring 16. . 1. Reference numeral 24 indicates an insulating sleeve for preventing the coil spring 16 from coming into electrical contact with the nozzle holder 2. Particularly in a small fuel injection valve, the coil spring 16 and the spring chamber 15 This is necessary because the space between it and the wall is narrow. Note that the nozzle holder 6, plate member 3, sleeve net 5, and nozzle holder 2 are also all made of conductive materials.

In order to maintain electrical insulation between the inner peripheral surface of the guide hole 7 of the nozzle holder 6 and the outer peripheral surface 8a of the needle valve 8 facing thereto,
A thin film 26 is formed on the outer peripheral surface 8a of the needle valve 8 by the manufacturing method of the present invention.

In this embodiment, the membrane 26 is a compound of ZrO□-E, where X varies from zero near its surface to 2 near the needle valve 8. That is, the thin film 26 is zirconium oxide (ZrO□) near the outer surface;
In the intermediate region, the oxygen content θ gradually decreases as it goes inward, and in the vicinity of the needle valve 8 it is simply composed of Zr.
It becomes. This is illustrated in FIG. 2, where the membrane 26 extends from t=Q to 1=1 on the surface of the needle valve 8. The region (2) up to is made of simple metal (Zr), and the region (2) from t=t2 to its outer surface 1=18 is made of ZrO□.

1 between areas I and II. (1(12). In the region ■, the thin film 26 is ZrO□
- It is composed of a non-stoichiometric compound represented by D,
Here, X varies from 2 to 0. As a result, thin film 2
The electrical resistance of the needle valve 6 gradually increases as the distance from the needle valve 8 increases, and increases until it is close to the guide hole 7.

When the thin film 26 has a structure as shown in FIG. 2, the metal layer region (2) adheres to the metal valve body 8 with very strong adhesion, and the region (2) forms a bond between the valve body 8 and the nozzle holder 6. It is possible to ensure insulation between the two and also ensure wear resistance. Then, in transition region ■, region 1 has different properties.
．． Since II 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 transition region ■ The coefficient of thermal expansion is region 1, II
, and the value gradually changes along the thickness direction, which has the advantage that the peeling resistance of the thin film against thermal shock that occurs 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.

A needle valve 8 arranged in a vacuum container 31 is connected to a variable DC high pressure source 3.
It is connected to the negative electrode of No. 2 via a switch SW. An evaporation source 34 provided on a partition plate 33 within the vacuum container 31 is connected to a positive electrode of a DC high pressure source 32. Reference numeral 41 indicates an ionization electrode for adjusting the routing speed. It is connected to the negative pole of another variable DC power supply 42 that is grounded. Therefore, Z placed in the evaporation source 34
When r is melted and evaporated by electrons from the electron gun 35, the blating speed can be adjusted by adjusting the voltage of the variable DC power supply 42 by the action of the ionization electrode 410. Inside the vacuum container 31 is the vacuum pump 3
6 to maintain the required degree of vacuum.

When the inside of the vacuum container 31 reaches a required degree of vacuum, the cock 39 is opened and Ar gas is introduced from the vacuum chamber 40. The switch sw6 is closed to apply a full DC voltage between the valve body 8 and the evaporation source 34, and a glow discharge is generated in the vacuum container 31, thereby cleaning the inside of the container. After the cleaning is completed, the Zr is evaporated, and the ionized Zr is routed to the surface of the valve body 8 by the negative high pressure applied to the valve body 8.
As a result, region (2) is formed. When forming region (3), firmly press the needle valve (8) onto the region (It-) which is a metal layer.
In order to deposit the ZR metal layer on the needle valve 8, the variable DC high voltage source 32 is adjusted to increase its output voltage, and the ZR ions collide with the desired outer peripheral surface of the needle valve 8 with high energy, thereby depositing the ZR metal layer on the needle valve 8. Good adhesion can be achieved.

When the thickness of the area ■ reaches a predetermined value, the cock 37
is opened to allow oxygen, which is a reactive gas, to gradually flow into the vacuum container 31 from the female pump 38, thereby gradually increasing the partial pressure of oxygen. As a result, above the area ■, zrO
A transition region ■ indicated by □-D begins to be formed. By gradually increasing the partial pressure of the reaction gas (oxygen gas) in the vacuum container 31 over time, a transition region m having an oxygen content gradient shown in FIG. 2 is formed. As the partial pressure ratio of oxygen gas increases, the physical properties of the resulting compound change from conductive to insulating. As already mentioned, when the material to be deposited is insulating, high applied voltage will cause dielectric breakdown on the surface of the member to be coated, reducing the quality of the deposited thin film as an insulating film. It turns out. In order to avoid this, the output voltage of the variable DC high pressure source 32 is gradually lowered as the partial pressure ratio of oxygen gas increases, thereby preventing dielectric breakdown from occurring on the surface of the needle valve 8, which is the member to be coated. Then, each variable DC high pressure source 32, 42 is adjusted: In this way, a state is finally reached in which ZrO2 is generated without causing a dielectric breakdown phenomenon on the surface of the needle valve 8, and a transition is made. An insulating region (2) made of ZrO2 is formed on the region (2) to a desired thickness.

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 grating method. By changing the value of the high voltage applied as described above together with the partial pressure control of the reactant gas, the quality of the insulating part on the surface of the thin film 26 can be made high, and it is robust and has excellent wear resistance. An insulating film can be formed.

According to the above manufacturing method, the inside of the thin film 26 is in a low oxygen content state with good adhesion to metal or is made of metal itself,
Since the metal layer portion (Zr layer portion) of the thin film is strongly adhered to the surface of the metal member to be coated, the adhesion between the thin film and the member to be coated is extremely good.
Since the high-quality insulating layer is firmly attached to this metal layer through the transition layer, a high-quality insulating thin film can be formed on the surface of the needle valve 8 with extremely strong adhesion. .

In the above example, Zr was used as the evaporation substance and 0□ was used as the reaction gas, but the material of the adhesion layer is not limited to these, and other inorganic insulating materials may be used. I can do it. Therefore, as evaporated substances, At, Cr,
Si, etc. were used, while N2. C2H2
etc. can be used.

However, it is necessary to avoid using evaporated metals that, together with the evaporated substance and the metal of the member to be coated, form metal compounds whose properties change rapidly. Furthermore, it is necessary to avoid combinations of metals and reactive gases that produce compounds that interact with the evaporated substance and abruptly change the physical properties of either the evaporated metal or the produced compound.

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.
In addition to the ion grating method, the ion grating method as well as the Suno J? Other physical vapor deposition methods such as tuttering may also be used.

When the adhesion layer 26 is formed by the ion silating method, the temperature during the treatment can be low (550°C or less), so material distortion occurs in the valve body 8 which has already been heat treated, or tempering occurs. Furthermore, since it is a dry system in a closed container, there is no need to worry about pollution.

(Effects) 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 in the thickness direction is formed on the surface of the desired member to be coated. However, since the surface of the thin film is coated with the required insulating compound, it is mechanically resistant.

In addition to being able to form an insulating thin film that has extremely high peeling resistance against thermal shock, when forming a thin film with this structure using a physical vapor deposition method, the voltage applied to the member to be coated is controlled by the gas. Since the voltage is adjusted according to the partial voltage control and the entire voltage is applied when forming the insulating region of the thin film, an excellent effect is achieved in that the insulating properties of the thin film can be made of extremely high quality.

[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 a 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 the ion blating apparatus for forming the entire thin film shown in FIG. 1. 8... Needle valve, 26... Thin film, 31... Vacuum container,
32... variable DC high pressure source, 34... evaporation source, 35...
...electron gun, 36...vacuum ponder. Patent applicant: Diesel Kiki Co., Ltd. Agent Patent attorney: Masa Takano Pickles 1 Figure 2 A Katabayashi side p. 5 gM Figure 3 Procedural amendment (voluntary) 6 October 7, 1986

Claims (1)

[Claims] 1. In a thin film manufacturing method for forming an insulating thin film on the surface of a member to be coated, in a reaction chamber in which the member to be coated is placed, ionized vapor of a predetermined metal reacts with this metal to achieve a predetermined insulating property. reacting with a predetermined reaction gas that forms a compound, gradually changing the ratio of the partial pressure of vaporization of the metal to the partial pressure of the reaction gas during the reaction, and evaporating the ionized substance in the reaction chamber; A method for producing a thin film, characterized in that the magnitude of the voltage applied to the member to be coated is reduced as the insulating compound is formed.