JPS6141764A - Method and apparatus for vapor deposition under vacuum arc reaction - Google Patents

Abstract

PURPOSE:To improve ionization efficiency and to perform vapor deposition stably at high speed without contaminating a film, by introducing reaction gas through a small hole provided at a discharging surface of a cathode and converging a vacuum arc cathode base point to the circumference of the opening hole end. CONSTITUTION:Small hole connecting a gas exit 4 and a gas inlet 5 is provided at the discharging surface 3 of the cathode 2. Reaction gas is ionized by a plasma generating system 6 provided just before the exit 5, then sent from the inlet 5. The cathode 2 is covered with a shield 7 such as Ti maintaining a narrow gap excluding the surface 3. A converging coil 9 is provided at the outer circumference of a water cooled anode 8 in front of the cathode 2, to control arbitrarily plasma beam diameter by magnetic field. In this way, discharge is stabilized, plasma reaction efficiency is improved, and good quality ceramic cover can be vapor deposited at a high speed. Trouble of short circuit between cathode and anode due to shield material evaporation and conductive material adhesion is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION In a tokamak-type fusion reactor, a coating material in which titanium carbide or the like is deposited on a metal surface is used for parts of the vessel wall that surrounds the plasma. These materials suffer catastrophic damage to the surface coating layer due to the large heat flux during plasma abnormalities that occur during fusion reactor operation.

This is a trap. Parts metal that has lost its coating layer can be directly replaced with Glazma K1.
1 liter and is contaminated with plasma. Therefore, the development of technology to locally repair damaged areas on the spot, and the technology to cover the damage,
Research and development is required not only for nuclear fusion reactors but also for internal coating or repair technology for various chemical plant reaction devices.

BACKGROUND OF THE INVENTION Conventionally, ceramic coating methods using vacuum arc discharge are known. As shown in FIG. 5, the method is as shown in FIG. A reactive gas was introduced into the container, and a plasma flow of metal vapor and reactive gas was applied to the substrate 13 for vapor deposition. 14 indicates an exhaust port.

According to such a method, (1) it is necessary to increase the area of the discharge surface in order to stabilize arc discharge;

(2) Since the reactive gas is introduced into the vacuum container, the reaction pressure must be increased to some extent in order to stabilize the arc discharge.

(3) In order to prevent the cathode spot from escaping from the discharge surface, an insulating material is used in contact with the cathode, so the material of the insulating material is evaporated by the arc and mixed into the deposited film as impurities. Additionally, ceramic is deposited on the insulating material, often causing short circuit problems.

(4) This method cannot repair damaged areas on the inner wall surfaces of nuclear fusion reactors and chemical plant reactors on the spot. 〇Purpose of the Invention The present invention was made to eliminate the drawbacks of the conventional vacuum arc reactive vapor deposition method. It is possible to deposit
Moreover, it is an object of the present invention to provide a vacuum arc reactive vapor deposition method that has a high ionization rate due to vacuum arc discharge, is stable at high speed, does not contaminate the deposited film, and does not cause any trouble, and also provides a vapor deposition apparatus thereof.

Structure of the invention (1) Metal vapor generated by vacuum arc discharge
Create a plasma flow of I and reactive gas and collect it 1
A vacuum arc cathode having pores in its discharge surface is used, and a reactive gas is blown out from the pores and convergently transported with a single true pole in a method of vapor deposition on a substrate by bundle transport. AC reactive deposition method.

(2) The vacuum arc cathode consists of a discharge surface with pores for blowing out reactive gas, and the cathode is surrounded by a cooling jacket, and the entire cathode except for the discharge surface is covered with a high melting point shield with a narrow gap. A vacuum arc reactive vapor deposition apparatus is characterized in that an anode is provided in front of a cathode discharge surface, and a converging coil is provided on the outer periphery of the anode.

To explain the present invention based on the drawings, Fig. 1 is an explanatory diagram of an electrode according to the present invention, in which a cathode 2 is cooled by a water cooling jacket 1, and a discharge surface 3 has a gas outlet 4 with an open end M and a gas port. The reactive gas provided with the pores connecting with the tooth electrode is ionized in advance by a gas plasma generation system 6 using high frequency or the like provided just before the gas population 5 of the tooth electrode, and then sent from the gas population 5.

On the other hand, in order to prevent the cathode bright spot of the vacuum arc formula from escaping from the discharge surface, the cathode is covered with a ruled 7 made of a material with a high melting point such as titanium, with a gap as narrow as possible, around the area other than the discharge surface. It is being said. A converging coil 9 is provided around the outer periphery of an anode 8 which is cooled by water cooling or the like in front of the cathode 2, and the plasma beam diameter is arbitrarily controlled by a magnetic field.

In the above configuration, the gas plasma generation system 6 does not necessarily need to be provided immediately before the gas population 5.

In the present invention, the discharge surface of the cathode 5 is provided with a pore for the outlet of the reactive gas, and the reactive gas is introduced through the pore, so that the cathode bright spot of the vacuum arc can be concentrated around the opening end. The discharge can be highly stabilized. Also,
Introducing a reactive gas that is ionized beforehand can stabilize the discharge and increase the efficiency of the plasma reaction, thereby allowing high-speed deposition of high-quality ceramic coatings. Furthermore, since the area around the cathode other than the discharge surface is covered with a shield at a small interval, there is no problem of short circuit between the cathode and the anode due to evaporation of the shield material or adhesion of conductive substances.

Effects of the Invention In addition to the above-mentioned effects, according to the present invention, (1) discharge is highly stabilized, so that the range of atmospheric gas pressure and discharge current that can sustain discharge is expanded; (2) At the same discharge current and evaporation rate, compared to the conventional method, the bright spots of the bare arc are concentrated and stabilized, so there is a significant increase. (3) Since the discharge surface of the cathode can be made small, the vapor deposited material can be discharged at high density from the small area of the cathode surface. Local coverage is therefore possible at desired locations. (4) Since a cylindrical cathode with a small cross-sectional area can be used, the cathode material can be
Moreover, it is easy to continuously replenish the vapor, and it is also easy to form an electrode structure suitable for on-site vapor deposition. Excellent effects such as these can be achieved.

EXAMPLE Ti was supplied as a cathode material, and N was ionized as a reactive gas. As a result of photographing and observing the discharge surface of the cathode surface, it was found that when the reactive gas was introduced from a place away from the cathode in the conventional method, the arc cathode bright spot moved around the entire discharge surface, but in the present invention When the reactive gas is introduced through the pores provided on the discharge surface of the cathode, the arc cathode bright spot is only around the reactive gas outlet, and the vapor deposited material is densely deposited, regardless of whether or not ionization is performed before introducing the reactive gas. It was found that it was released.

The relationship between atmospheric gas pressure and discharge current is shown in FIG. 2. In the figure, A is the conventional method, B and C are the methods of the present invention, B is the case where the reactive gas is introduced without being ionized in advance, and C is the case where the reactive gas is introduced without being ionized in advance. The value of the lattice constant of crystallographically sound TiN is 4.24A. Considering this point, the atmospheric gas pressure generated by a film having a stoichiometric composition (Ti/N=1.0) is 3X10"~IX
It can be seen that the pressure is in the range of 10-” Torr. According to the conventional method, stable discharge cannot be obtained in this pressure range, but
According to the method of the present invention, it is possible to enter the stable discharge region and therefore obtain a film of good quality.

Figure 4 shows the deposition rate. In the figure, A shows the conventional method, and B and C show the method of the present invention. B is a case in which the reactive gas is introduced without being ionized beforehand, and C is a case in which the reactive gas is introduced after being ionized in advance. As shown in the figure, the evaporation rate is fast according to the method of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing one embodiment of the electrode according to the present invention, Fig. 2 is a diagram showing the relationship between atmospheric gas pressure and discharge current, and Fig. 3 is a diagram showing the lattice constant of the TiN film obtained by the method of the present invention and atmospheric gas pressure. Figure 5 is a comparison diagram of vapor deposition speed.
The figure shows a schematic diagram of electrodes in the conventional method. 1: Water cooling jacket 2: Cathode 3: Discharge surface 4: Reactive gas outlet 5: Reactive gas population 6: Gas plasma generation system 7: Shield
8: Water-cooled anode 9: Convergent coil 1o: Anode 11: Insulating material 12: Vacuum vessel 13: Substrate
14: Exhaust Ro A line: In the case of the conventional method, B line: When the reactive gas is not ionized in advance in the method of the present invention, C line 2.
If the counter-injection gas is ionized in advance,

Claims (1)

[Claims] 1. A vacuum arc having pores on the discharge surface in a method of creating a plasma flow of metal vapor and reactive gas generated by vacuum arc discharge, and convergently transporting the plasma flow to deposit it on a substrate. Using a cathode, reactive gas is blown out from the pores, and the entire cathode except for the discharge surface of the vacuum arc is covered with a high melting point shield with a narrow gap, and the bright spot of the vacuum arc cathode is connected to the gas outlet on the discharge surface. A vacuum arc reactive evaporation method that is characterized by generating a plasma stream concentrated in the periphery and convergently transporting it at the anode. 2. The vacuum arc reactive vapor deposition method according to claim 1, wherein immediately before introducing the reactive gas, the reactive gas is ionized by electric discharge and introduced. 3. The vacuum arc cathode consists of a discharge surface with pores for blowing out reactive gas, and the cathode is surrounded by a cooling jacket, and the entire cathode except the discharge surface is covered with a high melting point shield with a narrow gap. A vacuum arc reactive vapor deposition apparatus characterized in that an anode is provided in front of a cathode discharge surface, the anode being separated and covered and having a converging coil on its outer periphery. 4. The vacuum arc reactive vapor deposition apparatus according to claim 3, wherein a reactive gas plasma generator is provided immediately before the inlet of the reactive gas.