JP7160531B2 - Surface treatment equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus, and more particularly to a surface treatment apparatus that uses plasma to apply a predetermined treatment such as film formation to the surface of an object to be treated.

Conventionally, there is an ion plating apparatus disclosed in Patent Document 1, for example, as this type of surface treatment apparatus. The conventional ion plating apparatus disclosed in Patent Document 1 includes a vacuum chamber whose interior is evacuated. This vacuum chamber is grounded. An evaporation source is provided in the vacuum chamber. This evaporation source has a crucible containing an evaporation material that is the material of the film, and an electron gun that heats and evaporates the evaporation material contained in this crucible. Furthermore, a substrate as an object to be processed is placed above the evaporation source in the vacuum chamber. The substrate is supplied with substrate bias power, which is negative DC power with reference to ground potential, from a substrate bias power supply device outside the vacuum chamber. Additionally, a shutter is provided between the crucible and the substrate in the vacuum chamber. The shutter is driven to open and close by an opening and closing mechanism. Specifically, when the shutter is placed between the object to be processed and the crucible, the shutter is in a closed state in which the surface of the object to be processed is shielded from the opening of the crucible, and is removed from the space between the object to be processed and the crucible. By being placed in the open position, the object to be processed selectively transitions to an open state in which the surface of the object to be processed is exposed toward the opening of the crucible.

An ionization mechanism is provided between the crucible and the shutter. The ionization mechanism has a thermionic emission filament and an ionization electrode. Both ends of the thermionic emission filament are connected to a filament heating power supply outside the vacuum chamber. The thermionic emission filament is heated by being supplied with AC filament heating power from the filament heating power supply and emits thermionic electrons. Also, one end of the thermionic emission filament is grounded. An ionizing electrode is provided above the thermionic emission filament. The ionization electrodes are then connected to an ionization power supply outside the vacuum chamber. The ionization power supply supplies ionization electrode power, which is positive DC power with reference to ground potential, to the ionization electrode. In other words, the ionization power supply has the ionization electrode as the anode and the thermionic emission filament as the cathode, and supplies DC ionization electrode power to both of them.

Further, a current detection device is provided for detecting the ionization electrode current, which is the current flowing through the ionization electrode. A current value detected by this current detection device is supplied to a filament control device as thermoelectron amount control means. The filament controller controls the filament heating power supply so that the current detected by the current detector is constant, that is, the ionization electrode current is constant. Thereby, the heating temperature of the thermionic emission filament, that is, the amount of thermionic electrons emitted from the thermionic emission filament is appropriately adjusted.

According to the ion plating apparatus having such a configuration, a copper (Cu) film can be formed on the surface of a substrate made of stainless steel, for example. In this case, a high-purity copper evaporation material is contained in the crucible. After that, the inside of the vacuum chamber is evacuated, and a so-called evacuation is performed. After this evacuation, with the shutter closed, filament heating power is supplied from the filament heating power supply to the thermionic emission filament. This heats the thermionic emission filament and emits thermionic electrons. At the same time, ionization electrode power is supplied from the ionization power supply to the ionization electrode. That is, the ionization electrode is used as an anode and the thermionic emission filament is used as a cathode, and ionization electrode power is supplied to both of them. Thermal electrons emitted from the thermionic emission filament as the cathode are then accelerated toward the ionization electrode as the anode. When the thermal electrons flow into the ionization electrode, a corresponding current flows through the ionization electrode, that is, the ionization electrode current described above flows.

In this state, the evaporation material inside the crucible is heated by the electron gun and evaporated. The vaporized particles of this vaporized material flow upwards, ie towards the closed shutter. Along the way, the accelerated thermoelectrons inelasticly collide with vaporized particles of the vaporized material. The impact dissociates and ionizes the evaporative particles of the evaporative material. This ionization causes electrons to be flipped from the evaporated particles of the evaporation material, and the ejected electrons flow into the ionization electrode. This increases the ionization electrode current flowing through the ionization electrode. By continuing this phenomenon, a plasma containing ionized evaporated particles is generated. This plasma aspect is a low voltage, high current arc discharge.

Further, substrate bias power is supplied to the substrate from the substrate bias power supply device. At the same time, the shutter is opened. As a result, ionized evaporation particles, that is, copper ions, are incident on the surface of the substrate to form a copper film on the surface of the substrate.

The ionization electrode current flowing through the ionization electrode is correlated (proportional) to the plasma density, that is, correlated to the amount of ions generated between the thermionic emission filament and the ionization electrode. For example, the greater the ionization electrode current, the greater the amount of ions generated, and the greater the amount of ions incident on the surface of the object to be processed. This ionization electrode current, that is, the amount of ions generated, fluctuates due to the lowering of the melting surface of the evaporation material as the evaporation material evaporates or the deformation of the thermionic emission filament. This variation in the amount of ions produced is not preferable because it greatly affects the quality and reproducibility of the film. For this reason, the filament control device performs control so that the current detection value by the current detection device is constant as described above, that is, the ionization electrode current is constant.

In addition, according to this conventional ion plating apparatus, a film thickness sensor for detecting the thickness of the film formed on the surface of the substrate is provided near the substrate. This film thickness sensor is connected to a film thickness monitor outside the vacuum chamber. The film thickness monitor calculates the formation rate of the film formed on the surface of the substrate, the so-called film formation rate, based on the film thickness detected by the film thickness sensor. Then, the output of the electron gun is controlled so that the deposition rate is constant. The control to keep the film formation rate constant and the control to keep the ion generation amount constant can be performed independently of each other. Therefore, it is possible to flexibly respond to various demands regarding the quality and properties of the film.

Moreover, according to this conventional ion plating apparatus, it is also possible to form a film other than a copper film. For example, it is possible to form a metal film other than a copper film, a conductive film other than a metal film, or an insulating film. In addition, by introducing a reactive gas that is a film material different from the evaporation material into the vacuum chamber, a compound film that is a compound of the particles of the evaporation material and the particles of the reactive gas can be formed. It is also possible to carry out a film formation process by a so-called reactive ion plating method.

JP 2013-60649 A

By the way, although not specified in Patent Document 1, the shutter described above is provided to stabilize the film formation process in the initial stage of the film formation process. That is, immediately after the electron gun starts heating the evaporation material in the crucible, the evaporation amount of the evaporation material is small and unstable. In this state the plasma is unstable. If a film forming process is performed on the surface of the substrate in such a state, a good quality film cannot be formed. For example, different quality coatings are formed in the early and later stages of the deposition process. In addition, in the film formation process by the reactive ion plating method described above, films having different compositions are formed at the initial stage and the subsequent stage of the film formation process. Furthermore, immediately after the heating of the evaporation material is started, impurities may be contained in the evaporation particles of the evaporation material. , causing peeling of the coating. To avoid such inconvenience, the shutter is closed until the plasma stabilizes. After the plasma is stabilized, the shutter is opened. Thereby, a good quality coating can be formed.

The shutter is made of a non-magnetic metal having relatively high mechanical strength, heat resistance and corrosion resistance, such as stainless steel such as SUS304. The shutter is mechanically coupled to the vacuum chamber (wall portion) via the opening/closing mechanism, and at the same time, is electrically connected to the vacuum chamber via the opening/closing mechanism. Grounded.

Although such shutters are necessary to produce good quality coatings, it has now been found that there are other problems caused by the shutters that affect the quality of the coatings. That is, it is assumed that the shutter is driven to open and close while plasma is being generated. For example, when the shutter is in the closed state, the electrons in the plasma flow into the ionization electrode as described above, and also more or less into the shutter, which has the same potential as the ionization electrode (ground potential). The sum of the electrons flowing into the ionization electrode and the electrons flowing into the shutter appears as the above-mentioned ionization electrode current. The amount of electrons flowing into the shutter increases as the position of the shutter is closer to the position of the thermionic emission filament.

Here, when the shutter transitions from the closed state to the open state, the position of the shutter moves away from the position of the thermionic emission filament. As a result, the amount of electrons flowing into the shutter is reduced to approximately zero. As a result, the amount of ions generated decreases, that is, the plasma density decreases, and as a result, the ionization electrode current decreases. This state is resolved by the control for making the ionization electrode current constant by the above-mentioned filament control device, but it takes some time until then. This is because the filament control device is given a relatively slow response (time constant) so that the control for making the ionization electrode current constant by the filament control device is stably performed. according to.

Therefore, when the film formation process is carried out, the shutter is closed until the plasma is stabilized as described above, and when the shutter is opened after the plasma is stabilized, for some time immediately after the shutter is opened, , less ions are produced. In short, in the initial stage of the film formation process immediately after the shutter changes from the closed state to the open state, the film formation process is performed in a state where the amount of ions generated is unstable. This means that the amount of ions generated is unstable in the interface portion on the lower layer side of the film, which is not preferable for the film in which the interface portion is extremely important. In particular, in the film forming process by the above-described reactive ion plating method, the amount of ions generated greatly affects the quality of the film, and this has a significant effect on the quality of the film.

That is, in the conventional ion plating apparatus, there is a problem that the film forming process cannot be stably performed from the initial stage of the film forming process. This problem is not limited to the film forming process, and similarly occurs in other surface treatments such as nitriding treatment and carburizing treatment using plasma.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a surface treatment apparatus capable of performing a predetermined process such as a film forming process using plasma stably from the initial stage. and

In order to achieve this object, the present invention provides a surface treatment apparatus for applying a predetermined treatment to the surface of an object to be treated using plasma, comprising a vacuum chamber, plasma generation means, a shutter, and prevention means. An object to be processed is placed inside the vacuum chamber. Also, the inside of the vacuum chamber is evacuated. In addition, the vacuum chamber itself is grounded. The plasma generating means generates plasma inside the vacuum chamber. The shutter is transitionable between a closed state and an open state inside the vacuum chamber. Here, the closed state is a state in which the surface of the object to be treated is prevented from being subjected to a predetermined treatment. On the other hand, the open state is a state in which a predetermined process is applied to the surface of the object to be processed. The prevention means then prevents electrons in the plasma from flowing into the shutter.

That is, according to the present invention, when the shutter is in the closed state, the surface of the object to be treated is not subjected to the predetermined treatment. Then, when the shutter is in the open state, the surface of the object to be treated is subjected to a predetermined treatment. Furthermore, the prevention means prevents electrons in the plasma from entering the shutter. Thus, for example, the transition of the shutter from closed to open does not change the density of the plasma. Therefore, the predetermined processing can be stably performed from the initial stage of the predetermined processing.

The prevention means may include insulation means for electrically insulating the shutter from the plasma generation means. Electrons in the plasma are prevented from flowing into the shutter by the prevention means including such insulation means.

Also, the shutter may be made of an electrically insulating material instead of providing the prevention means. Thus, electrons in the plasma are prevented from flowing into the shutter by forming the shutter from an electrically insulating material.

The predetermined process referred to here may be a film forming process for forming a film on the surface of the object to be processed. In this case, the film forming process can be stably performed from the initial stage of the film forming process.

Furthermore, the film forming process referred to here may be a film forming process using an ion plating method. That is, according to the present invention, even in the film formation process by the ion plating method, the film formation process can be stably performed from the initial stage.

In order to carry out film formation processing by this ion plating method, for example, accommodation means, evaporation means, and bias power supply means may be provided. In addition, the plasma generation means may include a hot cathode and ionization power supply means. Specifically, the storage means is arranged below the object to be processed inside the vacuum chamber and is grounded , and stores the evaporation material, which is the material of the film. The evaporating means evaporates the evaporation material contained in the containing means. The bias power supply means supplies a predetermined bias power to both the housing means as an anode and the object to be processed as a cathode. The thermionic cathode is provided between the container and the object to be processed inside the vacuum chamber, and emits thermionic electrons. The ionization power supply means uses the storage means as an anode and the hot cathode as a cathode, and supplies DC ionization power to both of them to ionize the evaporation material evaporated by the evaporation means.

According to this configuration, the evaporation material stored in the storage means is evaporated by the evaporation means. The thermionic cathode then emits thermionic electrons. Furthermore, DC ionization power is supplied to both of the housing means as an anode and the hot cathode as a cathode by the ionization power supply means. Thermal electrons emitted from the hot cathode as the cathode are then accelerated toward the accommodation means as the anode. Then, the accelerated thermoelectrons collide inelastic collisions with vaporized particles of the vapor deposition material. The impact dissociates and ionizes the vaporized particles of the vapor deposition material. By this ionization, electrons are flicked from the vaporized particles of the vapor deposition material, and the flicked electrons flow into the containing means. By continuing this phenomenon, a plasma containing ionized evaporated particles is generated. This plasma aspect is a low voltage, high current arc discharge, as in the conventional ion plating apparatus described above. In this state, bias power is supplied by the bias power supply means to both the housing means as the anode and the object to be processed as the cathode. Then, the ionized evaporated particles of the vapor deposition material are accelerated toward the object to be processed and impinge on the surface of the object to be processed. As a result, a film containing vaporized particles of the vapor deposition material is formed on the surface of the object to be processed, that is, a film forming process is performed.

That is, according to this configuration, the containing means acts as an anode for generating plasma (arc discharge). Therefore, no ionization electrode is required as in the conventional ion plating apparatus. As a result, compared to conventional ion plating apparatuses, the overall configuration of the apparatus can be simplified and the cost can be reduced. Also in this configuration, the film forming process can be stably performed from the initial stage of the film forming process.

Also, in this configuration, the shutter may be placed in the first position between the hot cathode and the workpiece to be in the closed state. The shutter may be placed in an open state by being placed at a second position away from between the hot cathode and the object to be processed.

According to this configuration, the shutter is placed at the first position between the hot cathode and the object to be processed, so that the surface of the object to be processed is shielded from the housing means. is in a closed state in which film formation processing as a predetermined processing is not performed. By placing the shutter at the second position away from the hot cathode and the object to be processed, the surface of the object to be processed is exposed toward the housing means, that is, the surface of the object to be processed It becomes an open state in which a film formation process is performed on the substrate.

Further, the first position in this configuration is preferably a position between the hot cathode and the work piece, closer to the hot cathode.

That is, since the first position is closer to the hot cathode, when the shutter is placed at the first position, the shutter speed is higher than in a configuration in which the first position is closer to the object to be processed. The position of the shutter and the position of the containing means are close. As a result, the size of the shutter can be reduced. On the other hand, since the first position is closer to the hot cathode, when the shutter is placed at the first position, the position of the shutter is near the region where the plasma is generated. Even with such a configuration, according to the present invention, electrons in the plasma are prevented from flowing into the shutter, and the film forming process can be stably performed from the initial stage of the film forming process. In other words, the present invention is particularly useful in such arrangements.

By the way, in this configuration, the current flowing through the ionization power supply means, so to speak, the ionization current, is correlated (proportional) to the density of the plasma, more specifically to the amount of ions generated between the hot cathode and the accommodation means. do. For example, the greater the ionization current, the greater the amount of ions generated, and the greater the amount of ions incident on the surface of the object to be processed. This ionization current, that is, the amount of ions generated, fluctuates due to the lowering of the melting surface of the evaporation material as the evaporation material evaporates or the deformation of the thermionic emission filament. The variation in the amount of ions produced greatly affects the quality and reproducibility of the film. Therefore, ionization current detection means and thermoelectron emission amount control means may be further provided.

That is, the ionization current detection means detects the ionization current flowing through the ionization power supply means. The thermoelectron emission amount control means controls the amount of thermoelectrons emitted from the hot cathode so that the value of the ionization current detected by the ionization current detection means is constant, that is, the amount of ions generated is constant. do. As a result, uniformity of coating quality and maintenance of reproducibility are achieved.

In this configuration, gas introducing means may be further provided. This gas introduction means introduces a reactive gas, which is a coating material different from the evaporation material, into the interior of the vacuum chamber. As a result, a compound film, which is a compound of evaporated particles of the evaporation material and particles of the reactive gas, can be formed, making it possible to perform a film formation process by a so-called reactive ion plating method. In the film formation process by this reactive ion plating method, the amount of ions generated greatly affects the quality of the film, so the present invention is useful for the film formation process by such a reactive ion plating method.

As described above, according to the present invention, in performing a predetermined process such as a film forming process using plasma, the predetermined process can be stably performed from the initial stage.

FIG. 1 is a diagram showing a schematic configuration of an ion plating apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram specifically showing the construction of the shutter in the first embodiment. FIG. 3 is a diagram showing the closed state and open state of the shutter in the first embodiment. FIG. 4 is a graph showing the relationship between the ionization voltage and the thermionic current in the first example together with that in the comparative example. FIG. 5 is a diagram showing transition of the ionization current when the shutter changes from the closed state to the open state in the first embodiment together with that in the comparative example. FIG. 6 is a diagram showing a schematic configuration of an ion plating apparatus according to a second embodiment of the invention.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.

The first embodiment is an example in which the present invention is applied to the ion plating apparatus 10 shown in FIG. As shown in FIG. 1, an ion plating apparatus 10 according to the first embodiment includes a substantially cylindrical vacuum chamber 12 . The vacuum chamber 12 is made of a metal having relatively high mechanical strength and relatively high heat resistance and corrosion resistance, such as stainless steel such as SUS304, and its wall is grounded. An exhaust port 14 is provided at an appropriate position on the wall of the vacuum chamber 12, for example, at the bottom. A vacuum pump (not shown) is connected as an exhaust means. The diameter (inner diameter) inside the vacuum chamber 12 is, for example, approximately 700 mm, and the height dimension is, for example, approximately 1000 mm. Further, the upper portion of the vacuum chamber 12 is formed in a substantially dome shape in order to improve the mechanical strength of the vacuum chamber 12 and the like.

Inside the vacuum chamber 12, an evaporation source 16 is arranged near the bottom thereof. This evaporation source 16 has a generally cup-shaped (more specifically, generally cylindrical shape with an open top) copper crucible 18 as storage means, and a 270° deflection type electron gun 20 as evaporation means. there is The crucible 18 of these accommodates an evaporative material 22, which is a coating material to be described later. The diameter of the opening of this crucible 18 is, for example, 60 mm, and the depth dimension is, for example, 20 mm. On the other hand, the electron gun 20 heats and evaporates the evaporation material 22 contained in the crucible 18 . The output Wg of this electron gun 20 is controlled by a dedicated power supply device (not shown) outside the vacuum chamber 12, and is, for example, 10 kW at maximum. Although not shown in detail, the crucible 18 is provided with a hearth liner made of a metal with a high melting point, such as tantalum (Ta), having a shape and dimensions matching the interior of the crucible 18 . Evaporative material 22 is contained within the liner. The evaporation source 16 has a water-cooled cooling mechanism to prevent the crucible 18 from overheating. The housing of this evaporation source 16, including the crucible 18, is grounded.

An object to be processed, such as a substrate 26 , is arranged above the evaporation source 16 . The substrate 26 is held by a substrate table 28 as holding means with its surface, strictly speaking, the surface to be processed, facing the evaporation source 16 , especially the opening of the crucible 18 . The distance from the surface of the substrate 26 to the evaporation source 16, for example, the distance to the opening of the crucible 18 varies depending on the shape and dimensions of the substrate 26, but is generally 250 mm to 700 mm.

Further, the substrate table 28 is connected outside the vacuum chamber 12 to a radio frequency (RF) power supply 30 as bias power supply means. Specifically, the board base 28 is connected to one of the two output terminals of the high-frequency power supply device 30 . The other output terminal of the high frequency power supply 30 is grounded. An impedance matching box (MB: Matching Box) 31 is provided between the high-frequency power supply device 30 and the substrate table 28 as matching means for matching the impedance between the two. The high-frequency power supply 30 outputs high-frequency power with a frequency of 13.56 MHz as the bias power Wb. Further, when the high-frequency power as the bias power Wb is supplied to the substrate table 28, a negative DC voltage with reference to the ground potential as the reference potential is naturally induced in the substrate table 28, which is called self-bias. voltage is generated. In other words, the crucible 18 at the ground potential is used as an anode, and the substrate 26 held on the substrate table 28 is used as a cathode.

Furthermore, a filament 34 for emitting thermionic electrons as a hot cathode is provided between the evaporation source 16 and the substrate table 28 and near the evaporation source 16, in other words, slightly above the opening of the crucible 18. It is The filament 34 is, for example, a tungsten (W) wire having a diameter of 1 mm. The filament 34 extends horizontally at a position 10 mm to 100 mm, for example 50 mm, away from the opening of the crucible 18 . Although not shown in detail, the filament 34 is spirally formed to increase its surface area and efficiently emit thermoelectrons, which will be described later. Specifically, the filament 34 is formed in a spiral with a diameter of 6 mm, the number of turns is 10 (turns), and the length of the spiral portion is 40 mm.

Both ends of the filament 34 are connected outside the vacuum chamber 12 to a filament heating power supply 36 as a hot cathode heating power supply means. The filament heating power supply 36 supplies AC power as filament heating power Wf to the filament 34 . The filament 34 is supplied with the filament heating power Wf and heated to emit thermoelectrons. The capacity of the filament heating power supply 36 is, for example, 2.4 kW (=40 V×60 A) at maximum. Also, the filament heating power Wf may be DC power instead of AC power. In any case, the filament heating power supply 36 should be able to heat the filament 34 to a temperature sufficient to cause the filament 34 to emit thermoelectrons, for example, to about 2000.degree. C. to 2500.degree.

In addition, one end of the filament 34 is connected outside the vacuum chamber 12 to an ionization power supply 38 as an ionization power supply means. The ionization power supply 38 supplies the filament 34 with ionization power Wd, which is positive DC power with reference to ground potential. In other words, the ionization power supply 38 supplies DC ionization power Wd to both the crucible 18 at ground potential as an anode and the filament 34 as a cathode. The capacity of this ionization power supply 38 is, for example, 9 kW (=60 V×150 A) at maximum.

Further, a current detection device 40 as ion current detection means is provided between the ionization power supply 38 and the ground. The current detector 40 detects the current component of the ionization power Wd, that is, the ionization current Id flowing through the ionization power supply 38 . A value of the ionization current Id detected by the current detection device 40 is supplied to a heating control device 42 as thermoelectron emission amount control means. The heating control device 42 controls the filament heating power supply 36 so that the value of the ionization current Id detected by the current detection device 40 is constant, that is, the ionization current Id is constant. Thereby, the heating temperature of the filament 34, that is, the amount of thermal electrons emitted from the filament 34 is appropriately adjusted.

A shutter 44 is provided at a position closer to the filament 34 between the filament 34 and the substrate table 28 in the vacuum chamber 12 . Strictly speaking, the shutter 44 is placed between the filament 34 and the substrate table 28 and closer to the filament 34 when in a closed state, which will be described later. The shutter 44 is formed in a substantially disc shape, and is provided with one main surface directed toward the opening of the crucible 18 as the lower surface and the other principal surface directed toward the substrate table 28 as the upper surface. The shutter 44 is coupled to a shutter driving mechanism 48 as shutter driving means through an insulator 46 as insulating means.

Specifically, as shown in FIG. 2, the shutter 44 has a body portion 442, a collar portion 444, and a coupling protrusion 446. As shown in FIG. The body portion 442 is formed in a disc shape, and has a diameter of, for example, 150 mm and a thickness of, for example, 2 mm. The flange portion 444 is a reinforcing member that mechanically reinforces the body portion 442 . The collar portion 444 is formed in a cylindrical shape, and is provided so as to extend along the periphery of the main body portion 442 and protrude in a direction away from one main surface of the main body portion 442 . The projection dimension of this collar portion 444 (from one main surface of main body portion 442) is, for example, 10 mm, and the thickness dimension of said collar portion 444 is, for example, 2 mm. The coupling projecting portion 446 is provided so as to linearly project in the radial direction of the main body portion 442 from an appropriate portion of the peripheral portion of the main body portion 442 . The coupling protrusion 446 is formed in a substantially linear ruler shape, and its thickness dimension is larger than the thickness dimension of each of the body portion 442 and the collar portion 444, for example 5 mm. The main body portion 442, the flange portion 444, and the connecting projection portion 446 are integrated by a non-magnetic metal having relatively high mechanical strength, heat resistance, and corrosion resistance, such as stainless steel such as SUS304. is formed in The shutter 44 is provided with one main surface of the body portion 442 on the side where the flange portion 444 protrudes as the aforementioned lower surface, and the other principal surface of the body portion 442 as the aforementioned upper surface.

The coupling protrusion 446 of the shutter 44 is coupled to the shutter driving mechanism 48 through the insulator 46 as described above. connected to the part side. The insulator 46 is formed in a substantially rectangular parallelepiped shape, has relatively high mechanical strength, has relatively high heat resistance and corrosion resistance, and is made of an electrically insulating material such as alumina ( Al ₂ O ₃ ). Between the insulator 46 and the coupling protrusion 446 of the shutter 44, a cover 50 of suitable shape and size is provided. This cover 50 is provided to prevent a later-described coating, particularly a conductive coating, from adhering to the entire surface of the insulator 46 . That is, when the conductive coating is deposited over the entire surface of the insulator 46, the shutter 44 and the shutter driving mechanism 48 (support member 482) are electrically connected via this conductive coating. In that case, there is no point in interposing the insulator 46 between the shutter 44 and the shutter driving mechanism 48 . To avoid this, a cover 50 is provided. Like the shutter 44, the cover 50 is made of a non-magnetic metal having relatively high mechanical strength, heat resistance and corrosion resistance, such as stainless steel such as SUS304. Further, a cutout portion 482a matching the shape of the insulator 46 is provided on one end side of the support member 482, and the shutter 44 is coupled to the cutout portion 482a via the insulator 46. Protrusions 446 are coupled. The connecting projection 446 of the shutter 44 and the insulator 46 are connected by a suitable connecting means, for example, by two screws 52,52. Similarly, the insulator 46 and the support member 482 are also coupled by two screws 54, 54, for example. Of course, other coupling means may be employed.

Returning to FIG. 1, the shutter driving mechanism 48 has a coupling member 484, a shaft member 486, a bearing member 488, and a shutter driving device 490 in addition to the support member 482 described above. The support member 482 is provided so as to extend in the horizontal direction, and the shutter 44 is coupled to one end thereof via the insulator 46 as described above. The other end of the support member 482 is fixed to one end of a round bar-shaped shaft member 486 via a connecting member 484 . The shaft member 486 is provided so as to extend in the vertical direction, and the other end is pulled out of the vacuum chamber 12 via a bearing member 488 . The bearing member 488 is fixed to the wall forming the bottom of the vacuum chamber 12 and holds the shaft member 486 rotatably while keeping the vacuum chamber 12 airtight. The other end of shaft member 486 is coupled to shutter driving device 490 outside vacuum chamber 12 . The shutter driving device 490 is an actuator such as a motor or a solenoid, and drives the shutter 44 to open and close by rotating the shaft member 486 over a predetermined angle as indicated by an arrow 490a in FIG. A power supply device for driving the shutter driving device 490 is omitted from the drawing.

Here, FIG. 3 shows the positional relationship between the shutter 44 and the crucible 18 when the shutter 44 is viewed from above. For example, FIG. 3A shows a state in which the shutter 44 is closed. As shown in FIG. 3A, when the shutter 44 is in the closed state, the shutter 44 (body portion 442) is located above the crucible 18, that is, positioned between the crucible 18 and the substrate 26. , so to speak, in the first position. As a result, the surface of the substrate 26 is shielded from the opening of the crucible 18 by the shutter 44 . FIG. 3B shows a state in which the shutter 44 is open. As shown in FIG. 3B, when the shutter 44 is in the open state, the shutter 44 is positioned outside the crucible 18, that is, outside between the crucible 18 and the substrate 26. position, so to speak, placed in the second position. As a result, the surface of the substrate 26 is exposed toward the opening of the crucible 18 without being shielded by the shutter 44 . By driving the shutter 44 to open and close in this way, the shutter 44 is placed in a closed state in the first position as shown in FIG. 3A and in a second position as shown in FIG. It selectively transitions to an open state placed in position.

Returning to FIG. 1 again, the bearing member 488 fixed to the wall of the vacuum chamber 12 rotatably holds the shaft member 486 while keeping the vacuum chamber 12 airtight as described above. Due to the structure of the bearing member 488, the shutter driving mechanism 48 including the bearing member 488 is electrically connected to the wall of the vacuum chamber 12, that is, grounded. However, since the insulator 46 is interposed between the shutter 44 and the shutter driving mechanism 48 as described above, the shutter 44 is electrically insulated from the vacuum chamber 12, that is, from the ground. be. In addition, the shutter 44 is electrically insulated from all other elements such as the filament 34 . That is, the shutter 44 is in an electrically floating state. The distance from the shutter 44 (lower surface) to the opening of the crucible 18 is, for example, 100 mm. In other words, the distance from shutter 44 to filament 34 is 50 mm.

In addition, gas introducing means for introducing various gases into the vacuum chamber 12 is provided at an appropriate position on the wall of the vacuum chamber 12, for example, a position above the shutter 44 and below the substrate table 28. A gas introduction pipe 56 is provided. The various gases referred to here include, for example, argon (Ar) gas as a discharge cleaning gas and oxygen (O ₂ ) gas as a reactive gas. Although not shown, the gas introduction pipes 56 are connected to respective gas supply sources outside the vacuum chamber 12 . In addition, the piping from each gas supply source includes an opening/closing valve as an opening/closing means for opening and closing the inside of the piping, a mass flow controller as a flow control means for controlling the flow rate of the gas in the piping, and the like. is provided.

Further, although not shown, a heating means such as a ceramic heater is provided at an appropriate position in the vacuum chamber 12 for heating the inside of the vacuum chamber 12 including the substrate 26 . The ceramic heater heats the interior of the vacuum chamber 12 including the substrate 26 by receiving heater heating power from a heater heating power supply provided outside the vacuum chamber 12 .

According to the ion plating apparatus 10 according to the first embodiment, an yttria (yttrium oxide: Y ₂ O ₃ ) film, which is an insulating coating, can be formed on the surface of the substrate 26 made of alumina, for example. .

For this purpose, first, solid high-purity yttrium (Y), which is the material of the yttria film, is placed in the crucible 18 . Granular yttrium having a diameter of about 3 mm to 5 mm is used as the yttrium. At the same time, the substrate 26 is attached to the substrate table 28 . Then, the inside of the vacuum chamber 12 is evacuated to about 10 ⁻³ Pa, and so-called evacuation is performed. Simultaneously with this evacuation, the inside of the vacuum chamber 12 including the substrate 26 is heated by the aforementioned ceramic heater, and the substrate 26 is heated to about 200.degree.

After this evacuation and heat treatment are performed for, for example, two hours, discharge cleaning (ion bombardment) treatment for cleaning the surface of substrate 26 is performed. Specifically, argon gas is introduced into the vacuum chamber 12 while the shutter 44 is closed. Then, the pressure inside the vacuum chamber 12 is maintained at 7×10 ⁻² Pa, for example. Further, the filament heating power Wf is supplied to the filament 34 . As a result, the filament 34 is heated and thermal electrons (primary electrons) are emitted from the filament 34 . At the same time, ionization power Wd is supplied to the filament 34 . That is, the ionization power Wd is supplied to both the filament 34 as a cathode and the evaporation source 16 including the crucible 18 as an anode. Thermal electrons emitted from the filament 34 as the cathode are then accelerated toward the evaporation source 16 as the anode, particularly toward the crucible 18 located near the filament 34 . The accelerated thermoelectrons then collide inelastic collisions with argon gas particles. As a result, the argon gas particles are ionized. Due to this ionization, electrons (secondary electrons) are flipped from (the outermost shells of) argon gas particles, and the flipped electrons flow into the crucible 18 . As this phenomenon continues, plasma is generated by arc discharge. At this time, the ionization voltage Vd, which is the voltage component of the ionization power Wd, is set to 40V. Then, the filament heating power Wf is controlled so that the ionization current Id, which is the current component of the ionization power Wd, is 30 A, that is, the amount of thermoelectrons emitted from the filament 34 is controlled.

Then, when the plasma is stabilized, more specifically, when the fluctuation amount of the ionization current Id settles within a predetermined range, the high-frequency power as the bias power Wb is supplied to the substrate table 28 . As described above, the bias power Wb is superimposed with the negative potential self-bias voltage with reference to the ground potential. The held substrate 26 is used as a cathode and is supplied to both of them. At this time, the bias power Wb is adjusted so that the self-bias voltage is approximately -500V. Then the shutter 44 is opened. Then, ionized argon gas particles, ie, argon ions, are incident on the surface of the substrate 26 . The impact cleans the surface of the substrate 26 .

After this discharge cleaning process is performed for 10 minutes, for example, a film forming process for forming an yttria film is performed. First, the shutter 44 is closed. At the same time, the introduction of argon gas into the vacuum chamber 12 is stopped. Oxygen gas is introduced into the vacuum chamber 12 instead of this argon gas. Then, the pressure inside the vacuum chamber 12 is maintained at 3×10 ⁻² Pa, for example. Further, the electron gun 20 of the evaporation source 16 is energized. An electron beam is thereby emitted from the electron gun 20 . Then, the electron beam irradiates the evaporation material 22 inside the crucible 18 . Upon being irradiated with this electron beam, the evaporation material 22 is heated, melted, and evaporated. The output Wg of this electron gun 20 is gradually increased to, for example, 3.6 kW (=9 kV×400 mA). At this time, the filament heating power Wf and the ionization power Wd are supplied to the filament 34 , so the thermoelectrons emitted from the filament 34 are accelerated toward the crucible 18 . The accelerated electrons inelastic collide with the evaporated particles of the evaporated material 22 . As a result, the evaporated particles of the evaporation material 22 are ionized. This ionization causes electrons to be flipped from the evaporated particles of the evaporation material 22 , and the ejected electrons flow into the crucible 18 . Similarly, electrons accelerated from the filament 34 toward the crucible 18 inelasticly collide with oxygen gas particles. As a result, oxygen gas particles are ionized. This ionization causes electrons to be flipped from the oxygen gas particles, and the flipped electrons flow into the crucible 18 . As this phenomenon continues, plasma is generated by arc discharge, as in the discharge cleaning process described above. The ionization voltage Vd, which is the voltage component of the ionization power Wd, is set at 25V. Then, the filament heating power Wf is controlled so that the ionization current Id, which is the current component of the ionization power Wd, becomes 80A. Furthermore, the bias power Wb is adjusted so that the aforementioned self-bias voltage is approximately -400V.

Then, when the plasma is stabilized, the shutter 44 is opened. Then, the ionized evaporation particles of the evaporation material 22, ie, yttrium ions, and the ionized oxygen gas particles, ie, oxygen ions, are incident on the surface of the substrate . As a result, an yttria film, which is a compound of yttrium ions and oxygen ions, is formed on the surface of the substrate 26 . In short, a compound film called the yttria film is formed by the film forming process by the reactive ion plating method.

This film forming process is continued until an yttria film having a desired film thickness is formed, and then terminated by closing the shutter 44 . Furthermore, the energization of the electron gun 20 is stopped. At the same time, the introduction of oxygen gas into the vacuum chamber 12 is stopped. Also, the supply of the bias power Wb to the substrate 26 is stopped. Then, the supply of the filament heating power Wf to the filament 34 is stopped, and the supply of the ionization power Wd to the filament 34 is stopped. This extinguishes the plasma. Then, the inside of the vacuum chamber 12 is evacuated again, and after a suitable cooling period of about 30 minutes is placed in this state, the pressure inside the vacuum chamber 12 is gradually returned to the atmospheric pressure. After that, the inside of the vacuum chamber 12 is opened, and the substrate 26 is taken out from the inside of the vacuum chamber 12 . This completes a series of surface treatments including the film forming process for forming the yttria film.

By the way, as described above, the shutter 44 in the first embodiment is in an electrically floating state. This is for the following reasons.

First, assume that the shutter 44 is grounded as in the conventional ion plating apparatus described above. In this hypothetical configuration, it is assumed that the shutter 44 is driven to open and close while plasma is being generated. In this case, when the shutter 44 is in the closed state, the electrons in the plasma flow into the crucible 18 as described above, and at the same time flow more or less into the shutter 44 at the same potential as the crucible 18 (ground potential). The sum of the amount of electrons flowing into the crucible 18 and the amount of electrons flowing into the shutter 44 appears as the ionization current Id. The closer the position of the shutter 44 is to the position of the filament 34 , the greater the amount of electrons flowing into the shutter 44 .

Here, when the shutter 44 transitions from the closed state to the open state, the position of the shutter 44 moves away from the position of the filament 34 . As a result, the amount of electrons flowing into the shutter 44 is reduced to approximately zero. Along with this, the amount of ions generated decreases, that is, the plasma density decreases, and as a result, the ionization current Id decreases. This state is resolved by the control for making the ionization current Id constant by the heating control device 42, but it will take some time. This is because the heating control device 42 is given a relatively slow response so that the control for making the ionization current Id constant by the heating control device 42 is stably performed.

Therefore, in this imaginary configuration, for example, when the film formation process is performed, the shutter 44 is closed until the plasma is stabilized as described above, and when the shutter 44 is opened after the plasma is stabilized, the shutter 44 For some time immediately after is opened, less ions are produced. In short, in the initial stage of the film formation process immediately after the shutter 44 transitions from the closed state to the open state, the film formation process is performed in a state in which the amount of ions generated is unstable. This means that the amount of ions generated is unstable in the interface portion on the lower layer side of the film, which is not preferable for the film in which the interface portion is extremely important. In particular, in the film forming process by the above-described reactive ion plating method, the amount of ions generated greatly affects the quality of the film, and this has a significant effect on the quality of the film. The occurrence of such inconvenience is the same as in the conventional ion plating apparatus described above.

In contrast, according to the first embodiment, since the shutter 44 is in an electrically floating state, the electrons in plasma do not flow into the shutter 44 . Therefore, for example, even if the shutter 44 is driven to open and close while plasma is being generated, the density of the plasma does not change, that is, the amount of ions generated does not change. Therefore, according to the first embodiment, the film forming process can be stably performed from the initial stage in the film forming process. This allows good quality coatings to be produced with good reproducibility.

Several experiments were conducted to demonstrate the usefulness of this first embodiment.

First, after the inside of the vacuum chamber 12 is evacuated, a constant filament heating power Wf is supplied to the filament 34 to cause the filament 34 to emit thermal electrons. Then, the ionization power Wd is supplied to the filament 34 to accelerate the thermal electrons emitted from the filament 34 . Furthermore, the voltage value of the ionization voltage Vd, which is the voltage component of the ionization power Wd, is appropriately changed. It was confirmed how the ionization current Id, which is the current component of the ionization power Wd, changes when the voltage value of the ionization voltage Vd is appropriately changed in this way. That is, the relationship between the ionization current Id by only thermoelectrons emitted from the filament 34 without plasma generation, ie, the thermoelectron current, and the ionization voltage Vd was confirmed. The results are shown in FIG.

In FIG. 4, the bold solid line with circles indicates the experimental results of the first embodiment. In FIG. 4, the bold dashed line marked with □ indicates the experimental results for the comparative example of the first embodiment. This comparative example is the virtual configuration described above, that is, the configuration in which the shutter 44 is grounded. That is, as a comparative example, a configuration in which the shutter 44 is grounded was actually prepared, and the same experiment as in the first embodiment was conducted on this comparative example as well. The pressure inside the vacuum chamber 12 in this experiment is 1.2×10 ⁻⁴ Pa. The filament heating power Wf is 840 W (=21 V×40 A). Note that the shutter 44 is in a closed state.

As shown in FIG. 4, at each voltage value of the ionization voltage Vd, the comparative example has a larger ionization current Id than the first embodiment. For example, when the ionization voltage Vd is 30 V, the ionization current Id of the comparative example is about 0.1 mA larger than that of the first embodiment. Further, when the ionization voltage Vd is 60 V, the ionization current Id of the comparative example is about 0.3 mA larger than that of the first embodiment. This means that thermal electrons flow not only into the crucible 18 but also into the shutter 44 in the comparative example. In other words, in the first embodiment, thermal electrons flow only into the crucible 18, so the ionization current Id is smaller than that of the comparative example. In other words, the difference between the ionization current Id in the first embodiment and the ionization current Id in the comparative example represents the amount of thermoelectrons flowing into the shutter 44 .

Although not shown, in the first embodiment, it was confirmed that the ionization current Id does not change even when the shutter 44 is driven to open and close. That is, in the first embodiment, even when the shutter 44 is in the open state, the relationship between the ionization voltage Vd and the ionization current Id indicated by the thick solid line marked with a circle in FIG. 4 does not change. confirmed. On the other hand, in the comparative example, it was confirmed that the ionization current Id changes as the shutter 44 is driven to open and close. Specifically, in the comparative example, when the shutter 44 is in the open state, the relationship between the ionization voltage Vd and the ionization current Id is the same as in the first embodiment. It was confirmed that the relationship is the same as that shown by the thick solid line with circle marks in .

As described above, according to the first embodiment, unlike the comparative example, it was verified that thermal electrons do not flow to the shutter 44 . This is the same even when plasma is generated. That is, according to the first embodiment, even if the shutter 44 is driven to open and close while plasma is being generated, the density of the plasma does not change.

Next, the film formation process for forming the yttria film is performed in the manner described above. confirmed. The results are shown in FIG. FIG. 5(A) shows transition of the ionization current Id in the first embodiment. FIG. 5B shows transition of the ionization current Id in the comparative example described above.

As shown in FIG. 5A, in the first embodiment, the ionization current Id changes at a constant magnitude of approximately 80 A immediately after plasma is generated (discharge is started). Even when the shutter 44 transitions from the closed state to the open state, the ionization current Id is approximately 80 A, that is, unchanged. On the other hand, in the comparative example, as shown in FIG. 5B, the ionization current Id changes at a constant magnitude of approximately 80 A immediately after the plasma is generated. This is the same as in Example 1. However, immediately after the shutter 44 transitions from the closed state to the open state, the ionization current Id drops to about 60A, or about 20A (25%). Then, this ionization current Id returns to the original current value of 80 A over a period of about 1 minute. The reason why it takes about one minute for the ionization current Id to return to the original current value of 80 A is that the heating control device 42, which is responsible for the control for keeping the ionization current Id constant, takes about one minute as described above. This is due to the gradual responsiveness.

From the results shown in FIG. 5, it was demonstrated that according to the first embodiment, unlike the comparative example, the ionization current Id does not change even when the shutter 44 transitions from the closed state to the open state. . Then, according to the first embodiment, a transparent yttria film was formed. This means that a good quality yttria film was formed (generally, the quality of the yttria film is judged from the degree of transparency of the yttria film). In contrast, in the comparative example, a transparent yttria film was not formed, and a slightly dark yttria film was formed. That is, in the comparative example, a good quality yttria film cannot be formed.

As described above, according to the first embodiment, the film forming process using plasma can be stably performed from the initial stage. Thereby, a good quality coating can be formed with good reproducibility. In particular, it is possible to satisfactorily form the portion that will be the interface on the lower layer side of the coating.

In the first embodiment, the shutter 44 is electrically floating to prevent electrons in the plasma from flowing into the shutter 44. In addition, the shutter 44 is grounded. Negative potential power may be supplied with reference to the potential. This configuration more reliably prevents electrons in the plasma from flowing into the shutter 44 .

Further, the shape of the shutter 44 and the structure of the shutter driving mechanism 48 are not limited to those described in the first embodiment. These are appropriately determined according to the shape and dimensions of the interior of the vacuum chamber 12 .

In addition, although the case of forming the yttria film has been described in the first embodiment, the present invention is not limited to this. For example, by using silicon (Si) instead of yttrium as the evaporation material 22, a silicon dioxide (SiO ₂ ) film can be formed. Further, by using aluminum (Al) as the evaporation material 22, an alumina film can be formed. Of course, other oxide films can be formed. In addition to the oxide film, a carbide film, a nitride film, a carbonitride film, an oxynitride film, or the like can also be formed. In this case, a hydrocarbon-based gas such as acetylene (C ₂ H ₂ ) gas, nitrogen (N ₂ ) gas, or the like is appropriately used as the reaction gas. Furthermore, it is not limited to a compound film, and a single element film made of a single element can also be formed. When forming this single-element film, it is not necessary to introduce a reactive gas. When any film is formed, electrons in the plasma do not flow into the shutter 44, and the film formation process can be stably performed from the initial stage of the film formation process.

In addition, although the high-frequency power supply 30 is used as the bias power supply means, the present invention is not limited to this. A DC power supply, an asymmetrical pulse power supply, or the like may be employed depending on the type of substrate 26 and the type of coating. However, if the substrate 26 is made of an insulating material, it is essential to use the high-frequency power supply 30 to prevent charge-up.

A film thickness sensor and a film thickness monitor similar to those in the conventional ion plating apparatus described above may also be provided. The output Wg of the electron gun 20 may be controlled so that the film formation rate determined by the film thickness sensor and film thickness monitor is constant. According to this configuration, the control for making the film formation rate constant and the control for making the above-mentioned amount of generated ions constant can be performed independently of each other, so that the quality of the coating can be improved. It is possible to flexibly respond to various requests for characteristics.
[Second embodiment]
A second embodiment of the present invention will be described with reference to FIG.

The second embodiment is an example in which the present invention is applied to the ion plating apparatus 10a shown in FIG. As shown in FIG. 6, in the ion plating apparatus 10a according to the second embodiment, electrical is provided with a shutter 44a made of an insulating material. Since the structure other than this is the same as that of the first embodiment, the same reference numerals are given to the same parts, and the detailed description thereof will be omitted.

That is, the shutter 44a in the second embodiment itself is made of an electrically insulating material. In addition, the material is required to have relatively high mechanical strength, relatively high heat resistance and corrosion resistance, and not to generate gas that becomes an impurity in the film. Such materials include, for example, alumina.

As described above, according to the second embodiment, since the shutter 44a is made of an electrically insulating material, electrons in the plasma do not flow into the shutter 44a. Therefore, according to the second embodiment, similarly to the first embodiment, the film formation process using plasma can be stably performed from the initial stage. This allows good quality coatings to be produced with good reproducibility.

It should be noted that the entire shutter 44a is not formed of an electrically insulating material, but only the surface of the shutter 44a is covered with an electrically insulating material, thereby preventing the shutter 44 from entering the plasma. of electrons may be prevented from flowing in.

The contents described in the respective embodiments above are all specific examples of the present invention, and do not limit the technical scope of the present invention. That is, the present invention can be applied to situations other than those of each of the examples.

For example, the present invention can also be applied to the aforementioned conventional ion plating apparatus. That is, by applying the present invention to a conventional ion plating apparatus, electrons in plasma are prevented from flowing into the shutter. Thereby, the film forming process can be stably performed from the initial stage of the film forming process, and a good quality film can be formed with good reproducibility.

In the conventional ion plating apparatus, plasma is generated between the thermionic emission filament and the ionization electrode. The shutter is then positioned farther away from the thermionic emission filament as the cathode for generating the plasma than the ionization electrode as the anode for generating the plasma. In contrast, in each embodiment of the present invention, as described above, the distance between shutter 44 (or 44a) in the closed state and filament 34 as a cathode for generating plasma is is equivalent to the distance (50 mm) between the opening of the crucible 18 and the filament 34 as the anode for allowing the That is, the distance from the shutter 44 (or 44a) to the filament 34 in each embodiment of the present invention is shorter than the distance from the shutter to the thermionic emission filament in a conventional ion plating apparatus. Therefore, if the shutter 44 (or 44a) in each embodiment of the present invention is grounded, the amount of thermal electrons flowing into this shutter 44 (or 44a) is less than that in a conventional ion plating apparatus. There are many. In such a configuration, the present invention is extremely useful.

In addition, the present invention can be applied to any apparatus that performs surface treatment using plasma and has a shutter. For example, the present invention can be applied to a sputtering device or the like. Furthermore, the present invention can be applied not only to film forming processes but also to apparatuses for performing other surface treatments such as nitriding and carburizing using plasma.

DESCRIPTION OF SYMBOLS 10... Ion plating apparatus 12... Vacuum chamber 16... Evaporation source 18... Crucible 20... Electron gun 22... Evaporation material 26... Substrate 30... High frequency power supply 34... Filament 36... Filament heating power supply 38... Ionization power supply 40... Current Detector 42 Heating control device 44 Shutter 46 Insulator 48 Shutter driving mechanism 56 Gas introduction pipe

Claims (7)

A surface treatment apparatus that performs a film formation process by an ion plating method for forming a coating on the surface of an object to be treated using plasma,
A vacuum chamber that itself is grounded, in which the object to be processed is placed and whose interior is evacuated;
plasma generating means for generating the plasma inside the vacuum chamber;
A closed state in which the film- forming process is not applied to the surface of the object to be processed inside the vacuum chamber, and an open state in which the film- forming process is applied to the surface of the object to be processed. a transitionable shutter; and prevention means for preventing electrons in the plasma from flowing into the shutter; a containing means containing an evaporative material that is
Evaporation means for evaporating the evaporation material contained in the containing means, and bias power for supplying a predetermined bias power to the containing means and the object to be processed using the containing means as an anode and the object to be processed as a cathode. A supply means is provided, and the plasma generation means is configured to:
a hot cathode that is provided between the storage means and the object to be processed in the interior of the vacuum chamber and that emits thermal electrons; and the storage means is an anode and the hot cathode is a cathode. ionizing power supply means for supplying DC ionizing power to and to ionize the vaporized material evaporated by the vaporizing means. 2. The surface processing apparatus according to claim 1, wherein said preventing means includes insulating means for electrically insulating said shutter from said plasma generating means. 2. The surface processing apparatus according to claim 1, wherein said shutter is made of an electrically insulating material instead of providing said prevention means. The shutter is placed in the closed state by being placed at a first position between the hot cathode and the object to be processed, and is placed at a second position away from between the hot cathode and the object to be processed. 4. The surface treatment apparatus according to any one of claims 1 to 3 , wherein the open state is achieved by being opened. 5. The surface treatment apparatus according to claim 4 , wherein said first position is a position closer to said hot cathode between said hot cathode and said object to be treated. ionization current detection means for detecting the current flowing through the ionization power supply means; and heat for controlling the amount of thermal electrons emitted by the hot cathode so that the value of the current detected by the ionization current detection means is constant. 6. The ion plating apparatus according to any one of claims 1 to 5 , further comprising electron emission amount control means. 7. The surface treatment apparatus according to any one of claims 1 to 6 , further comprising gas introducing means for introducing a reactive gas, which is a material of said film different from said evaporation material, into said vacuum chamber.

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