JPH07228972A - Method and device for continuously treating metallic plate - Google Patents

Abstract

PURPOSE:To provide a method for continuously treating a metallic sheet which suppresses discharge at the rear surface of this metallic sheet and permits reverse magnetron discharge of a high discharge current density. CONSTITUTION:The glow discharge is generated between the metallic sheet 1 moving in a vacuum chamber 1 as a cathode and magnetron electrodes 3 provided with magnets 5, 6 at both electrodes as a cathode by a high-voltage DC power source 4 and a guard electrode 7 for preventing sputtering disposed on the rear side of the surface to be treated of the metallic sheet is provided with magnets 11, 12 in a direction repulsing from the magnet of the magnetron electrodes. The magnetic fields 13 thereof and the magnetic fields 10 generated from the magnetron electrodes are interfered with each other to decrease the magnetic fields transmitting the metallic sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for continuously treating metal plates, which are related to surface treatment techniques such as vacuum plating of metal plates.

[0002]

2. Description of the Related Art When a roll-shaped metal plate is vapor-deposited by vacuum vapor deposition or ion plating, pretreatment by ion bombardment is performed to increase the adhesion of the vapor-deposited film. This was ionized by introducing a gas for bombardment treatment into a vacuum chamber for pretreatment, using a metal plate as a cathode, a magnetron electrode with a magnet embedded in the electrode as an anode, and causing glow discharge between both electrodes. By accelerating the bombarding gas by the electric field of glow discharge and colliding with the metal plate,
It repels oxide films and water molecules attached to metal plates.

FIG. 3 shows the configuration of a conventional continuous processing apparatus using the ion bombardment method. In the figure, 1 is a metal plate transferred in the direction of the arrow, 2 is a vacuum chamber, and 3 is an anode magnetron electrode (magnetron anode) arranged in the vacuum chamber 2 in parallel with the transfer direction of the metal plate 1.
The magnetron anode 3 is connected to the positive pole of the high-voltage DC power supply 4, and each magnetron anode 3 has a plurality of magnets 5 and 6 embedded in the inner and outer circumferences of the electrode 3, as shown in FIG. In addition, the upper and lower polarities of the magnet 5 on the inner peripheral side and the upper and lower polarities of the magnet 6 on the outer peripheral side are opposite to each other. Reference numeral 7 denotes a guard electrode arranged in parallel inside the vacuum chamber 2 on the side opposite to the surface to be processed of the metal plate 1 and connected to the positive electrode of the high voltage DC power supply 4.
The metal plate 1 is connected to the negative pole of the high voltage DC power supply 4 via the roll conductor 8. Reference numeral 9 is a vacuum exhaust device.

In the conventional continuous processing apparatus, the metal plate 1
Of the magnetron anode 3 from the high voltage DC power supply 4 after the ion bombardment gas (for example, Ar gas) is introduced after the room air is sufficiently exhausted by the vacuum exhaust device 9. A high voltage is applied between the cathode and the metal plate 1 of the cathode. Then, a glow discharge is generated between the metal plate 1 and the magnetron anode 3, and the glow discharge ionizes the ion bombardment treatment gas and separates it into ions and electrons. Ions are accelerated by an electric field generated between the magnetron anode 3 and the metal plate 1 to obtain energy. The accelerated ions collide with the metal plate 1, and at this time, the metal plate 1 is affected by the velocity energy and mass of the ions.
The oxide film and water molecules adhering to the surface of the are blown away. This action is called ion bombardment and is widely used as a pretreatment for vacuum vapor deposition.

When performing single-sided vacuum plating of a metal plate with such a continuous processing apparatus, as shown in FIG.
A flat guard electrode 7 is provided on the opposite side of the surface to be processed at a distance of 5 to 10 mm to prevent discharge on the back surface of the metal plate 1. This utilizes the fact that when the distance between the electrodes is set to be equal to or less than the sheath thickness of glow discharge, the discharge impedance rapidly rises and it becomes difficult to maintain the discharge. The reason why the discharge on the rear surface of the surface to be processed is prevented is to prevent unnecessary sputtering due to ion bombardment.

By the way, the processing speed of the continuous processing apparatus in the continuous evaporation apparatus for metal plates is the same as the line speed of the evaporation apparatus. Since the discharge current of glow discharge is considered to be almost proportional to the number of ions colliding with the metal plate, the processing capacity is evaluated by the amount of electric power per unit area or the product of current and time. Therefore, in order to increase the processing capacity at the same plate passing speed, it is necessary to lengthen the line length of the continuous processing device or increase the discharge current density. As a method for increasing the current density of glow discharge, there is an inverse magnetron method using a magnetic field. This is because the orbit of the electron is bent when a magnetic field is applied to the moving electron, and as a result, the electron makes a spiral motion, and the discharge impedance is lowered by increasing the effective flight distance of the electron, It increases the probability of collision between the molecules of the bombarding gas and the electrons.
Therefore, as shown in FIGS. 3 and 4, the magnets 5 and 6 having N and S poles are embedded in the electrode 3 in an elliptical shape so that the S pole is on the inner side and the N pole is on the outer side. Is used. This method is called an inverse magnetron system, and this anode 3 is called a magnetron anode. In this case, the strength of the applied magnetic field greatly affects the effective flight distance of the electrons, and the strength of the magnetic field on the surface of the metal plate parallel to the metal plate needs to be about several hundred gauss. In the reverse magnetron method, the current density of glow discharge can be increased by adjusting the strength of the magnetic field generated by the magnets 5 and 6 embedded in the electrode 3 to an appropriate value.

[0007]

However, in the inverse magnetron system, when a magnet that generates a high magnetic flux density is embedded in the electrode in order to increase the discharge current density of glow discharge, the magnetic field intersecting with the metal plate becomes strong, Part of magnetic field lines 1
0 transmits through the metal plate 1 as shown in FIG. 3, and the back surface of the metal plate 1 forms a magnetic field as if it were a magnetron electrode. When the cathode plate, that is, the metal plate 1 in FIG. 3 serves as a magnetron electrode, electrons emitted from the electrode are restrained by the magnetic field and the electrons make a spiral motion, so that the effective flight distance of the electrons becomes extremely long. This discharge is called cathodic magnetron discharge, the discharge impedance is lower than that of the inverse magnetron discharge, and power is applied not only to the surface to be processed but also to the back surface. Ion bombardment adversely affects the quality of the back of the metal plate.

In the magnetron discharge that occurs on the back side of the surface to be processed, since the cathode sheath thickness is very thin, the effect of suppressing discharge by the guard electrode 7 is weakened, and the guard electrode 7 must be extremely close to the back surface of the metal plate. However, in an actual continuous processing facility, since the position of the metal plate varies depending on the thickness and tension of the metal plate, the distance between the guard electrode 7 and the metal plate 1 is set to 5
It is difficult to make it less than mm. Therefore, conventionally, by making the strength of the magnetic field weaker than the optimum value and weakening the strength of the magnetic field transmitted to the back surface of the metal plate 1, the distance between the guard electrode 7 and the metal plate 1 is sacrificed at the expense of the current density. The electric discharge on the back surface of the metal plate is suppressed without bringing them close to each other. for that reason,
There are problems that the continuous processing equipment becomes very long or high-speed processing cannot be performed.

The present invention has been made in order to solve the above problems, and by suppressing the discharge on the back surface of the metal plate, the metal plate capable of maximally utilizing the capability of reverse magnetron discharge. It is an object of the present invention to provide a continuous processing method and device.

[0010]

According to the present invention, the above-mentioned problems are solved by providing a magnet in a direction repulsive to the magnet of the magnetron electrode in a guard electrode for preventing sputtering which is arranged on the back side of the metal plate in the vacuum chamber. It has been resolved. That is, the method for continuously treating a metal plate according to the present invention is such that a metal plate that is transferred in a vacuum chamber is used as a cathode, a magnetron electrode arranged in the vacuum chamber and having a magnet provided as an electrode is used as an anode, and both electrodes are connected between the electrodes. In a continuous treatment method of a metal plate, which generates a glow discharge, and performs an ion bombardment treatment of the surface to be treated of the metal plate by the glow discharge,
It is characterized in that the guard electrode provided on the opposite side of the surface to be processed of the metal plate is provided with a magnet in a direction that repels the magnet of the magnetron electrode, thereby lowering the magnetic flux density of the magnetic field intersecting with the metal plate.

The metal plate continuous processing apparatus according to the present invention is a magnetron electrode in which a vacuum chamber and a metal plate which moves in the vacuum chamber are used as a cathode and which is arranged in the vacuum chamber and which is provided with a magnet as an electrode. As an anode, a high-voltage DC power source for generating glow discharge between both electrodes, and a continuous treatment apparatus for a metal plate provided with a guard electrode provided on the opposite side of the surface to be treated of the metal plate, in the guard electrode, A magnet is provided so as to repel the magnet of the magnetron electrode.

[0012]

By providing the guard electrode with a magnet that repels the magnet of the magnetron electrode, the magnetic field generated by the guard electrode interferes with the magnetic field generated by the magnetron electrode, and the magnetic field that penetrates the metal plate can be eliminated. Therefore, the cathode magnetron discharge on the back surface of the metal plate can be suppressed without weakening the magnetic field of the inverse magnetron electrode.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a continuous processing apparatus used in the method of the present invention, and FIG. 2 is a bottom view showing the guard electrode of FIG. In the present embodiment, the guard electrode 7 for preventing sputtering provided on the back side of the metal plate 1 has magnets 5 and 6 embedded in the magnetron anode 3 and magnets 11 on the inner circumference side so as to have polarities in a repulsive direction. The outer peripheral magnet 12 is embedded. That is, if the upper portion of the magnet 5 on the inner peripheral side of the magnetron anode 3 is, for example, the S pole, the upper portion of the magnet 11 on the inner peripheral side of the guard electrode 7 facing this is the S pole. Further, the magnet 12 on the outer peripheral side of the guard electrode 7 is arranged as the N pole so as to face the upper N pole of the magnet 6 on the outer peripheral side of the magnetron anode 3. The guard electrode 7 thus configured is arranged on the back side of the metal plate 1 in parallel with the metal plate 1 with the gap distance L of 10 mm. Other configurations are the same as those shown in FIG. 3 of the conventional example.

Next, the operation of this embodiment will be described. After the metal plate 1 is passed through the chamber of the vacuum chamber 2 and the room air is sufficiently exhausted by the vacuum exhaust device 9, a gas for ion bombardment treatment, for example, argon gas is introduced, and the pressure in the vacuum chamber chamber is 100 Pa. -1 Pa. The negative pole of the high-voltage DC power supply 4 is connected to the metal plate 1 via the roll conductor 8, and the positive pole of the high-voltage DC power supply 4 is connected to the magnetron anode 3 and the guard electrode 7.
When a potential difference of 300 to 1000 V is applied, a glow discharge is generated between the metal plate 1 and the magnetron anode 3. By this glow discharge, the gas for ion bombardment is ionized and separated into ions and electrons. Ions are accelerated by the electric field between the magnetron anode 3 and the metal plate 1 to obtain energy. The accelerated ions collide with the metal plate 1, and at this time, the oxide film and water molecules attached to the surface of the metal plate 1 are repelled by the velocity energy and mass of the ions. The action of the ion bombardment up to this point is exactly the same as the conventional one.

However, since the guard electrode 7 provided on the back side of the surface to be processed of the metal plate 1 for preventing sputtering is provided with the magnets 11 and 12 in a direction repelling the magnets 5 and 6 of the magnetron anode 3, respectively. As shown in FIG. 1, the magnetic field 13 generated from the guard electrode 7 and the magnetic field 10 generated from the magnetron anode 3 interfere with each other, and the magnetic field transmitted through the metal plate 1 can be eliminated. That is, the magnetic field 13 generated from the guard electrode 7 distorts the magnetic field 10 generated from the magnetron anode 3, reduces the magnetic field transmitted through the metal plate 1, and reduces the magnetic field parallel to the metal plate of the magnetic field on the surface to be processed of the metal plate 1. The component (horizontal component) is strengthened.

As described above, in order to lengthen the effective flight distance of electrons, the strength of the applied magnetic field needs to be several hundred Gauss, but in this embodiment, this value is set to 150 Gauss. In the conventional case, as shown in FIG. 3, the guard electrode 7 is a flat plate electrode. Therefore, when the magnetic field on the surface to be processed of the metal plate 1 is increased to 150 Gauss in the horizontal component, when the metal plate is a non-magnetic material, The horizontal component of the magnetic field on the back surface of the metal plate 1 is 1
20 to 130 gauss. At this time, a tunnel-shaped magnetic field line and a space 14 surrounded by the metal plate 1 are formed on the back surface of the metal plate 1. When glow discharge is generated in this state, the metal plate 1
The electrons emitted from the are trapped in a strong magnetic field, which causes a cathodic magnetron discharge. This discharge has a very high current density and not only scrapes the back surface of the metal plate 1 by sputtering by ion bombardment, but also suppresses the discharge because the thickness of the cathode sheath or the thickness called the cathode drop portion is narrow. Becomes difficult.
In order to prevent this state from occurring, it is necessary to set the magnetic flux density of the horizontal component that passes through the metal plate 1 to 50 Gauss or less. Therefore, conventionally, as shown in FIG. By placing the demagnetization plate 15 made of a ferromagnetic material, the magnetic field on the surface of the metal plate is weakened so that the cathode magnetron does not occur due to the magnetic field transmitted through the metal plate.

In the present invention, the magnetic field 13 generated from the guard electrode 7 and the magnetic field 10 generated from the magnetron anode 3 are used.
Are adjusted so that the magnetic field transmitted through the metal plate 1 is eliminated. Further, in this embodiment, the space 16 surrounded by the tunnel-shaped magnetic field lines and the metal plate 1 which slightly penetrates to the surface to be processed of the metal plate 1 is formed.

Further, according to the conventional method, in order to reduce the magnetic flux density of the horizontal component passing through the metal plate to 50 gauss or less, the magnetic flux density of the horizontal component on the surface of the metal plate can be only about 65 gauss. However, according to the present embodiment, there is no magnetic flux passing through the metal plate even though the magnetic flux density of the horizontal component on the surface of the metal plate is 150 gauss. As a result, the current density to the surface to be processed can be increased without causing strong discharge on the back surface of the metal plate. Therefore, the density of the discharge current applied to the metal plate can be increased, and the line length can be shortened at the same processing speed, and the line speed can be increased at the same processing length.

[0019]

As described above, according to the present invention, the guard electrode provided on the back side of the surface to be processed of the metal plate is provided with the magnet in the direction of repulsing the magnet of the magnetron electrode, so that the magnetic field intersecting with the electrode plate is eliminated. Since it was decided to lower the magnetic flux density of, the magnetic field of the magnetron electrode is not weakened, that is, the ability of the reverse magnetron discharge can be maximized,
In addition, it is possible to suppress the discharge on the back surface of the metal plate.
Therefore, it is possible to increase the discharge current, and it is possible to shorten the length or increase the speed of the continuous metal plate processing apparatus.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a metal plate continuous processing apparatus of the present invention.

FIG. 2 is a bottom view showing the guard electrode of FIG. 1 partially broken away.

FIG. 3 is a configuration diagram of a conventional metal plate continuous processing apparatus.

FIG. 4 is a partially cutaway top view of the magnetron electrode of FIG.

[Explanation of symbols]

 1 Metal Plate 2 Vacuum Chamber 3 Magnetron Anode 4 High Voltage DC Power Supply 5,6 Magnet 7 Guard Electrode 8 Roll Conductor 9 Vacuum Evacuation Device 11, 12 Magnet

Claims (2)

[Claims] 1. A glow discharge is generated between both electrodes by using a metal plate which is transported in the vacuum chamber as a cathode, and a magnetron electrode which is disposed in the vacuum chamber and which has a magnet provided on the electrode as an anode, and which generates a glow discharge between the electrodes. In the method of continuously treating a metal plate for performing an ion bombardment treatment on a surface to be treated of a metal plate, a guard electrode provided on the opposite side of the surface to be treated of the metal plate is provided with a magnet in a direction repulsive to the magnet of the magnetron electrode. Thus, the method for continuously treating a metal plate is characterized in that the magnetic flux density of the magnetic field intersecting with the metal plate is reduced. 2. A glow discharge is generated between the vacuum chamber and a metal plate that moves in the vacuum chamber as a cathode, and a magnetron electrode arranged in the vacuum chamber and provided with a magnet on the electrode is used as an anode. In a continuous processing apparatus for a metal plate having a high-voltage DC power supply to perform and a guard electrode provided on the opposite side of the surface to be processed of the metal plate, a magnet in a direction repulsive to the magnet of the magnetron electrode is provided in the guard electrode. A continuous processing device for metal plates, which is provided.