JPH06248443A - Ion plating device - Google Patents

Abstract

PURPOSE:To efficiently form a film on a metallic strip by preventing abnormal discharge. CONSTITUTION:The entire part of the metallic strip 1 continuously connected from a coil before a treatment to a coil after the treatment is housed into a vacuum vessel 4. The vacuum vessel 4 and a vapor deposition source 12 are set at the ground potential and a cathode which may be an abnormal discharge generating source is limited to the metallic strip 1 by applying the negative potential from the ground potential to the metallic strip 1. The abnormal discharge in the vacuum vessel 4 is suppressed by dropping the pressure in the vacuum vessel 4 down to <1X1/10<2>Torr. The potential of the metallic strip 1 is stabilized by a capacitor of a prescribed capacitance connected between the metallic strip 1 and the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion plating apparatus for continuously forming a vapor deposition film on a metal strip plate.

[0002]

2. Description of the Related Art A vacuum vapor deposition method or an ion plating method is used as a method for physically forming a thin film.

The vacuum vapor deposition method is a simple method of heating and evaporating a substance for forming a thin film in a vacuum and adhering the vapor to the surface of a metal or the like. A method of continuously forming has been conventionally used. For example, JP-A-2-205677 and JP-A-1-208467.
The methods disclosed in Japanese Patent Laid-Open No. 1-164759 and the like are
As shown in FIG. 4, the metal strip 1 is continuously fed from the feeding coil 2 and wound by the winding coil 3 while the vapor deposition chamber 5 is being wound.
Before and after, the inside of the vacuum container 4 having the inlet side differential exhaust chamber 8a, the pretreatment chamber 7 and the outlet side differential exhaust chamber 8b is passed. After the surface of the metal strip 1 is pretreated in the pretreatment chamber 7, the vapor deposition material 31 evaporates from the evaporation source 12 onto the surface of the metal strip 1 in the vapor deposition chamber 5.
To form a film. This method is a so-called air-to-air method in which the coil of the metal strip 1 before and after the treatment is installed in the atmosphere and only the vapor deposition treatment or the like is performed in a vacuum.

On the other hand, as shown in FIG. 5, the method disclosed in, for example, Japanese Patent Laid-Open No. 1-252278, all of the metal strip 1 including the coils before and after the treatment is loaded into the vacuum container 4. It is an in-line method.

Although these methods are different in system, they are common in that the metal strip 1 is set to the ground potential because it is intended for vacuum deposition processing. On the other hand,
The Ting method differs from the vacuum evaporation method in that a potential difference is applied between the substrate and the evaporation source containing the evaporation material. From the viewpoint of film quality, the ion plating method has many advantages over the vacuum evaporation method, such as high adhesion strength of the thin film to the substrate [Reference: Nikkan Kogyo Shimbun, "Basics of thin film formation (second
Version) "(Sho 59, 7, 30)," High-performance coating by vacuum technology "(Sho 62, 12, 22), etc.].

In the ion plating method, for example, as shown in FIG. 6, the electron gun 10 is fired in a vacuum container 4 maintained at a vacuum degree of about 1/10 ³ to 1/10 ⁵ torr. The fast electron 51 heats the vapor deposition material 11 in the evaporation source 12. By this heating, atoms or clusters 52a are ejected from the surface of the vapor deposition material 11 as a vapor flow. Some of the atoms or clusters 52a that have jumped out are ionized nodes 53.
Collide with the electrons 54 discharged from and become ions or cluster ions 52b. This ion or cluster ion 5
2b is -50 with respect to the evaporation source 12 by the bias power source 16.
A thin film is formed by colliding with and adhering to the substrate 55, accelerated by the potential difference, toward the substrate 55 applied with a negative potential of ˜-1000V.

In the ion plating method shown in FIG. 6, the vacuum container 4 and the evaporation source 12 are connected to the ground of the same potential, and the vacuum container 4 is set to a positive potential with respect to the substrate 55. The metal ions 52b are less likely to adhere to the vacuum container 4, and the metal ions 52b have a directivity to collide with the substrate 55 to improve the vapor deposition efficiency and the ionization efficiency.

However, the potential relationship that the substrate 55 is not grounded as in the ion plating method can be applied only to the batch equipment at the laboratory level in which the size of the substrate 55 is at most 50 cm × 50 cm. It has been considered very difficult to apply to the continuous processing equipment for continuously forming a thin film on the metal strip 1 described above.

The reason is that the substrate 55 is used to improve the film quality.
In order to perform the pretreatment of the shutter 6 in the batch equipment, for example, as shown in FIG.
1 is inserted, the shutter 61 is grounded to the ground, and the substrate 5
Ar gas is introduced from the Ar gas introduction device 62 between the No. 5 and the shutter 61. Then, the bias power supply 16 is applied to the substrate 55 at -50
A negative bias voltage of 0 to -2000 V is applied to generate a DC glow discharge between the substrate 55 and the shutter 61, and the substrate 5
5 bombardment treatment is performed. After that, the shutter is opened and the above-mentioned ion plating process is performed. What should be noted here is that the values of the bias voltage required when performing the pretreatment and the ion plating treatment are different. The value of this bias voltage can be changed because it is a batch facility.

On the other hand, in the continuous processing equipment shown in FIGS. 4 and 5, the potential of the metal strip 1 that is continuously fed cannot be changed between the pretreatment chamber 7 and the vapor deposition chamber 5, so the pretreatment chamber 7 The vapor deposition chamber 5 and the vapor deposition chamber 5 must be kept at the same potential. Moreover, in the continuous processing equipment, although not shown, there are many complicated machines such as a coil payout device, a coil winding device, a deflector roll, a seal roll, etc., which come into contact with the metal strip plate 1, and a vacuum. There are many ground potential components such as containers and vacuum pumps. Therefore, the metal strip 1 is
When a potential difference of 100 V or more is applied, abnormal discharge often occurs.

Therefore, when a thin film is continuously formed on the metal strip 1 by the ion plating method, the metal strip is set to the ground potential as disclosed in, for example, Japanese Patent Laid-Open No. 64-25982. , Applying a vacuum container or a potential shield plate equivalent to it, an evaporation source, etc. to a positive potential with respect to the ground,
As shown in JP-A-63-18062, while heating a pre-cleaned metal strip in the inlet duct of a vacuum container, it is given a negative polarity and sent to the vapor deposition chamber for film formation. There is.

[0012]

However, according to the method in which the metal strip plate is set to the ground potential, and the vacuum container, the potential shield plate corresponding thereto, the evaporation source, etc. are applied to the ground in a positive potential. Therefore, all parts other than the metal strip in the vacuum container must be insulated from the ground. It is very difficult and costly to apply the above-mentioned insulation measures to all vacuum vessels that are complicated due to various measures such as improvement of vapor deposition efficiency, improvement of film quality, uniformization of film thickness distribution. . In addition, the conductive vapor deposition material adheres to the part where insulation measures are taken over time, causing insulation deterioration, further insulation breakdown, and frequent problems such as abnormal discharge, which makes stable operation impossible. Measures were desired.

In addition, when a negative polarity is applied to a metal strip that has been washed in advance and the metal strip is sent to the vapor deposition chamber, even if the pressure in the vapor deposition chamber is set to about 1/10 ⁴ torr, the delivery coil chamber is started. As a result, the pressure is 1 in the inlet duct and outlet duct.
× 1/10 ² Torr or more easily. Paschen's law is established at a pressure of 1 × 1/10 ² torr or more. According to Paschen's law, the discharge start voltage V including abnormal discharge in a uniform electric field is the product PL of the pressure P and the electrode interval L. Involved.
Therefore, in a large vacuum device, if there is a metal strip plate to which a bias voltage is applied under a pressure of 1 × 1/10 ² torr or more, an abnormal discharge will occur between an earth member and a wide range of positional relationships. Is likely to occur. Therefore, there is a risk that abnormal discharge may occur in a place other than the deposition chamber. Also, in this case,
There is also a disadvantage that the cleaning and film forming process of the metal strip cannot be performed consistently.

Further, in a large ion plating apparatus for continuously forming a thin film on a metal strip having a width of about 500 mm or more by an ion plating method, discharge in a discharge space between an evaporation source and the metal strip. The impedance changes due to a frequency of several tens Hz to several kHz for some reason. Control of the bias power supply cannot catch up with such frequency fluctuations, and as shown in FIG. 8, for example, the discharge voltage fluctuates greatly with respect to the set voltage Vs, the effective applied power becomes unstable, and instantaneous overcurrent is generated. There was also a serious problem that the power supply was frequently shut down.

The present invention has been made to solve the above disadvantages, and an object thereof is to obtain an ion plating apparatus capable of preventing abnormal discharge, efficiently forming a film on a metal strip, and operating stably. It is what

[0016]

SUMMARY OF THE INVENTION An ion plating apparatus according to the present invention electrically insulates from a sending coil for sending a metal strip before processing to a winding coil for winding a metal strip after processing. Stored, pressure is 1 × 1 /
A vacuum vessel with a pressure lower than 10 ² torr, a bias vessel with a vacuum vessel and an evaporation source at an earth potential, a bias power source for applying a negative potential to the metal strip plate from the earth potential, and a metal. It is characterized by comprising a capacitor having a certain capacity or more connected between the strip plate and the evaporation source.

Further, it is preferable to connect a pretreatment power source using DC glow discharge in parallel with a bias power source for performing the above vapor deposition process. In this case, it is preferable to reduce the pressure in the vacuum container to less than 1 × 1/10 ² torr except for the pretreatment chamber.

[0018]

[Function] Generally, a glow discharge including abnormal discharge in vacuum occurs.
Electrons emission from the cathode is the origin of various discharges such as discharge and arc discharge. Therefore, in the present invention,
The entire metal strip that is continuously connected from the coil before treatment to the coil after treatment is housed in a vacuum container to electrically insulate the metal strip from the vacuum container, and to connect the vacuum container and the vapor deposition source. -A negative potential from the ground potential is applied to the metal strip to limit the cathode that can be the source of abnormal discharge to the metal strip, and the pressure in the vacuum container is set to 1 x 1/10 ² torr- To prevent abnormal discharge in the vacuum vessel.

Further, by connecting a capacitor having a certain capacity or more between the metal strip and the evaporation source set to the ground potential, the fluctuation of the discharge impedance in the discharge space is replaced with the charging and discharging of the capacitor. The discharge voltage is prevented from fluctuating and the discharge voltage is maintained at a substantially desired value.

Further, as pretreatment, a bombardment treatment by direct current glow discharge using Ar gas or the like is performed at the same time, but the pretreatment power source is electrically insulated from the ground, and the cathode of the pretreatment power source is electrically insulated. Between the evaporation source and the metal strip during ion plating by electrically contacting the metal strip with the metal strip via a conductor roll and matching the cathode side potential reference with the potential of the metal strip. It is possible to prevent a change in the discharge impedance and a change in the potential of the metal strip due to the abnormal discharge from becoming a disturbance of the pretreatment power supply control.

In pre utilizing discharge treatment chamber, high-speed processes implemented on 1/10 ¹ to 1/10 ² bets - - [0021] The DC glow but may need to be pressure Le, vacuum in this case By limiting the shield to the pretreatment chamber in the container to a limited extent, the pressure in the vacuum container can be reduced to 1
× Lower to less than 1/10 ² torr.

[0022]

FIG. 1 is a line configuration diagram showing an embodiment of the present invention. As shown in the figure, the metal strip 1 is a delivery coil 2
All of the winding coil 3 to the winding coil 3 are housed in the vacuum container 4. The vacuum container 4 has a delivery coil chamber 6 in which the delivery coil 2 is housed, a pretreatment chamber 7 and a differential evacuation chamber 8 in front of the vapor deposition chamber 5, and a winding coil 3 is housed in the rear stage of the vapor deposition chamber 5. It has a winding coil chamber 9. The inside of the vacuum container 4 is maintained at a vacuum degree of less than 1 × 1/10 ² torr, preferably less than 1 × 1/10 ³ torr. The vapor deposition chamber 5 is for forming a thin film on the metal strip 1 and contains the electron gun 10 and the metal vapor deposition material 11 and is connected to the anode of the bias power source 16 by an evaporation source 12
Have. A capacitor 23 having a large capacity is connected in parallel with the bias power source 16 between the metal strip 1 and the evaporation source 12. The pretreatment chamber 7 performs a bombardment treatment using a DC glow discharge before forming a thin film on the metal strip 1, and a pretreatment anode 13 connected to an anode of a pretreatment power source 18. And a shield 14.

The metal strip 1 from the delivery coil 2 to the winding coil 3 is electrically insulated from the vacuum container 4 by an insulating roll or the like. Since the entire metal strip 1 from the delivery coil 2 to the winding coil 3 is housed in the vacuum container 4 in this manner, the metal strip 1 can be insulated from the vacuum container 4 relatively easily.

The metal strip 1 is connected to the cathode of a bias power source 16 via a conductor roll 15 provided on the vapor deposition chamber 5 side, and a conductor roll 17 provided on the pretreatment chamber 7 side.
The cathode of the pretreatment power source 18 is connected via the. Further, the vacuum container 19 and the vacuum pump 19 connected to each chamber of the vacuum container 4 are connected to the ground. Further, the pretreatment power source 18 is electrically insulated from the vacuum container 4 and the like having an earth potential. A bias power source 12 applies a negative potential of -50 to -1000 V to the ground of the metal strip 1 in the vapor deposition chamber 5. In addition, the pretreatment electrode 13 in the pretreatment chamber 7
+500 to the metal strip 1 by the pretreatment power source 18
+ 2000V voltage is applied.

In the ion plating apparatus constructed as described above, the metal strip 1 delivered from the delivery coil chamber 6 is subjected to a pretreatment by a bombardment treatment utilizing a direct current glow discharge in the pretreatment chamber 7. After that, deposition chamber 5
Sent to. In the vapor deposition chamber 5, metal atoms (or clusters) are ejected from the metal vapor deposition material 11 heated by the fast electrons emitted from the electron gun 10. A part (several% to several tens%) of the protruding metal atoms form a metal plasma 20 between the metal strip 1 and the evaporation source 12 which are set to a negative potential. The metal ions (or cluster ions) of the metal plasma 20 are attracted to the metal strip 1 serving as the cathode and collide with each other to form a good quality thin film. The metal strip 1 subjected to the ion plating process in the vapor deposition chamber 5 is sent to the winding coil chamber 9 and wound.

When the thin film is formed, the vacuum container 4 and the evaporation source 12 are at the ground potential, and only the metal strip 1 is at a negative potential from the ground potential. Abnormal discharge in the chamber 5 can be suppressed. Also,
The pressure in the vapor deposition chamber 5 can be set to a low pressure of less than 1 × 1 × 10 ² torr to further prevent abnormal discharge from occurring.

Further, since the metal strip 1 and the evaporation source 12 are connected by the capacitor 23 having a large capacity, the metal strip 1
Even if the discharge impedance in the discharge space between the evaporation source 12 and the evaporation source 12 fluctuates for some reason, the capacitor 23
2 can absorb the fluctuation of the discharge impedance in the discharge space between the metal strip 1 and the evaporation source 12, and as shown in the change characteristic diagram of the discharge voltage of FIG.
The discharge voltage can be kept constant at an almost predetermined voltage Vs. Therefore, in combination with the above-mentioned prevention of abnormal discharge, a uniform thin film can be formed on the metal strip 1 for a long period of time.

The capacitance C of this capacitor 23 is 1000 (μ
F) or more, or when the current flowing between the evaporation source 12 and the metal strip 1 is I _B (A), it is approximately (C / I _B )
≧ 10 (μF / A), preferably _{(C / I B) ≧ 50} (μF /
When set to A), the discharge voltage can be stabilized.

As a pretreatment for the ion plating treatment, a bombardment treatment is performed in the pretreatment chamber 7.
This bomber is designed to improve the quality of the formed film.
The pretreatment power supply 18 for performing the doping treatment is electrically insulated from the ground, and the cathode side is in parallel with the cathode of the bias power supply 16 for the ion plating treatment as shown in the equivalent circuit diagram of FIG. It is connected to the metal strip 1. Therefore, the impedance 21 on the ion plating side
Fluctuates, and the bias voltage of the metal strip 1 is several tens of volts.
Even if it fluctuates in the liner, it is possible to prevent the influence thereof from affecting the discharge voltage for the pretreatment, and the pretreatment can be stably performed. On the contrary, even if the discharge voltage changes due to the change in the pretreatment-side impedance 22, the bias voltage on the ion-plating side does not change at all, and good ion-plating processing can be performed.

In the above embodiment, the inside of the vacuum container 4 is set to 1
The case where the pressure is set to less than × 1/10 ² torr has been described, but the pressure in the pretreatment chamber 7 using DC glow discharge is set to 1
The pretreatment speed can be increased by setting the order of / 10 ¹ to 1/10 ² tols. In this case, the abnormal discharge in the pretreatment chamber 7 can be suppressed by the shield 14.

In this way, the pressure in the pretreatment chamber 7 is reduced to 1/10 ¹
The pressure is set to about 1/10 ² torr, and the degree of vacuum is quickly increased by the differential exhaust chamber 8 provided between the pretreatment chamber 7 and the vapor deposition chamber 5 to increase the pressure in the vapor deposition chamber 5. The pressure can be less than 1 × 1/10 ² torr.

In the above embodiment, the case where the metal material is used as the vapor deposition material has been described, but any material may be used as long as it is a material that can be subjected to the ion plating treatment.

In the above embodiment, the case where the capacitor 23, which is independent of the bias power supply 16, is connected between the metal strip 1 and the evaporation source 12 has been described, but between the output terminals of the actual bias power supply 16 is described. There is a case where a capacitor having a small capacity is connected and built-in. However, even if the capacity of the capacitor built in the bias power supply 16 is increased and the capacitor 23 is replaced, the same effect as that of the above-described embodiment is exhibited. can do.

[0034]

As described above, according to the present invention, the entire metal strip plate, which is continuously connected from the coil before treatment to the coil after treatment, is housed in the vacuum container, and the metal strip plate and the vacuum container are separated from each other. It is electrically insulated, and the vacuum container and the vapor deposition source are set to the ground potential, and a negative potential from the ground potential is applied to the metal strip so that the cathode that can be the abnormal discharge generation source is limited to the metal strip. Therefore, abnormal discharge in the vapor deposition chamber of the vacuum container can be suppressed.

Further, by connecting a capacitor having a certain capacity or more between the metal strip and the evaporation source set to the ground potential, the fluctuation of the discharge impedance in the discharge space is suppressed by charging and discharging the capacitor. Since the discharge voltage is prevented from fluctuating, the discharge voltage can be maintained at a substantially desired value, and a uniform thin film can be stably formed on the metal strip.

Furthermore, by lowering the pressure in the vacuum vessel in which the metal strip is present to less than 1 × 1/10 ² torr, it is possible to prevent abnormal discharge from occurring more reliably, and It is possible to stably form a thin film on the metal strip plate.

When the bombardment process by DC glow discharge using Ar gas or the like is simultaneously performed as the pretreatment, the pretreatment power source is electrically floated with respect to the ground, and the cathodes of the both power sources are electrically suspended. Side is connected in parallel to the metal strip, and by matching the cathode side potential reference, interference between the evaporation source and the metal strip during ion plating is prevented, and the pretreatment of the metal strip and the ion strip are performed. The coating process can be performed stably and efficiently, and high productivity can be obtained.

Further, by providing a pressure difference between the pretreatment chamber utilizing direct current glow discharge and the vapor deposition chamber, the processing speed can be increased.

[Brief description of drawings]

FIG. 1 is a line configuration diagram showing an embodiment of the present invention.

FIG. 2 is a change characteristic diagram of a discharge voltage in the vapor deposition chamber of the above embodiment.

FIG. 3 is an equivalent circuit diagram of the above embodiment.

FIG. 4 is a line configuration diagram according to a conventional vacuum deposition method.

FIG. 5 is another line configuration diagram according to a conventional vacuum deposition method.

FIG. 6 is a configuration diagram showing a conventional ion plating process.

FIG. 7 is a configuration diagram showing a pretreatment of a conventional ion plating treatment.

FIG. 8 is a conventional discharge voltage change characteristic diagram.

[Explanation of symbols]

 1 Metal Strip 2 Delivery Coil 3 Winding Coil 4 Vacuum Container 5 Deposition Chamber 7 Pretreatment Chamber 12 Evaporation Source 16 Bias Power Supply 18 Pretreatment Power Supply 23 Capacitor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kibe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Takamine Mukai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo No. Nippon Steel Tube Co., Ltd.

Claims (3)

[Claims] 1. In an ion-plating apparatus for continuously depositing a vapor deposition material on a metal strip in a vacuum to form a coating film, a metal coil is fed from an untreated metal strip to a treated metal strip. A vacuum container in which the winding coil and the winding coil are electrically insulated and housed, and the pressure is reduced to less than 1 × 1/10 ² torr, and the vacuum container and the evaporation source are set to the ground potential, An ion preparatory apparatus comprising: a bias power source for performing a vapor deposition process by applying a negative potential to the metal strip plate to a negative potential, and a capacitor connected between the metal strip plate and the evaporation source and having a certain capacity or more. -A touching device. 2. The ion plating apparatus according to claim 1, wherein a pretreatment power source using DC glow discharge is connected in parallel with a bias power source for performing the vapor deposition process. 3. The pressure inside the vacuum container is set to 1 excluding the pretreatment chamber.
3. The ion-plating device according to claim 2, wherein the ion-plating device is lowered to less than 1/10 < ² > torr.