Reactive ion plating apparatus and method

Abstract

A reactive ion plating apparatus and method for stably forming a high-quality insulating coating. [Solution] According to the reactive ion plating device 10 of the present invention, an evaporation material 24 contained in a crucible 20 is heated by an electron gun 22 and evaporated. At the same time, an ionization power Wd is supplied to the crucible 20 as an anode and a hot cathode filament 34 that emits thermoelectrons as a cathode. This induces a plasma 100. Furthermore, a reactive gas is introduced into a vacuum chamber 12 via a hollow anode 46, and a hollow anode power Wh is supplied to the hollow anode 46. This induces a hollow anode plasma 200. Furthermore, a hollow anode filament 48 is provided at a gas outlet of the hollow anode 46. This hollow anode filament 48 becomes a stable anode by being heated by Joule heat.

Description

[Technical field]

[0001] The present invention relates to a reactive ion plating apparatus and method, and more particularly to a reactive ion plating apparatus and method for reacting particles of an evaporation material with particles of a reactive gas to form a reaction film, which is a compound of the particles of the evaporation material and the particles of the reactive gas, on the surface of a workpiece. [Background technology]

[0002] An example of this type of technology is disclosed in Patent Document 1. According to the technology disclosed in Patent Document 1, inside a vacuum chamber in which a workpiece is placed, an evaporation material is accommodated in a container provided below the workpiece. In addition, a hot cathode is provided between the container and the workpiece. Then, after the inside of the vacuum chamber is evacuated, the evaporation material accommodated in the container is evaporated by the evaporation means, and thermoelectrons (primary electrons) are emitted from the hot cathode. Furthermore, a first ionization power of direct current is supplied to the pair of electrodes, with the container serving as an anode and the hot cathode serving as a cathode. Then, the thermoelectrons emitted from the hot cathode are accelerated toward the container, and the accelerated thermoelectrons collide inelastically with the particles of the evaporation material, thereby ionizing the particles of the evaporation material. In addition, electrons repelled from the particles of the evaporation material due to this ionization flow into the container, and this phenomenon continues, thereby inducing plasma (metal vapor plasma when the evaporation material is a metal). The form of this plasma is a constant-voltage, high-current arc discharge. In addition, the amount of thermoelectrons emitted by the hot cathode is controlled so that the current component of the first ionization power is constant. The current component of the first ionization power is correlated (proportional) to the amount of ions in the plasma, in other words, correlated (proportional) to the density of the plasma. That is, the amount of thermoelectrons emitted by the hot cathode is controlled so that the density of the plasma is constant, and so-called feedback control is applied.

[0003] In addition, a reactive gas is introduced into the vacuum chamber through the hollow part of the hollow anode. A second ionization power of DC is supplied to the pair of electrodes, the hollow anode being the anode and the containing means being the cathode. Then, electrons in the plasma are accelerated toward the hollow anode, particularly toward the outlet of the hollow anode for the reactive gas into the vacuum chamber. The accelerated electrons then inelastically collide with particles of the reactive gas discharged from the outlet of the hollow anode, ionizing the particles of the reactive gas. As a result, a plasma is induced in the vicinity of the outlet of the hollow anode, so to speak, a hollow anode plasma (gas plasma) is induced. In the vicinity of the outlet of the hollow anode, the pressure of the reactive gas is high, that is, the density of the particles of the reactive gas is high, and therefore a high-concentration hollow anode plasma is induced. The hollow anode plasma is also a low-voltage, high-current arc discharge. Most of the electrons that contribute to the induction of the hollow anode plasma are plasma electrons (electrons with energy lower than the ionization voltage) among the electrons in the so-called main plasma induced by the supply of the first ionizing power described above. In other words, the thermoelectrons emitted from the hot cathode hardly contribute to the induction of the hollow anode plasma.

[0004] Furthermore, a bias power is supplied to the workpiece to accelerate the ionized particles of the evaporation material and the ionized particles of the reactive gas toward the surface of the workpiece, whereby a reaction film, which is a compound of the ionized particles of the evaporation material and the ionized particles of the reactive gas, is formed on the surface of the workpiece. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6788081 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the technology disclosed in Patent Document 1, various reaction films can be formed, and for example, a high-quality conductive film can be stably (with good reproducibility). However, there is a problem with insulating films, in that they cannot be stably formed. This is presumably because, when a film formation process for forming an insulating film is performed, the insulating film (strictly speaking, an insulating material) adheres (accumulates) to the hollow anode, particularly around the outlet of the hollow anode, thereby reducing the function of the hollow anode as an anode (electrode).

[0007] That is, when the function of the hollow anode as an anode is deteriorated, the number of electrons moving from the main plasma toward the hollow anode decreases. This makes the hollow anode plasma unstable, and the amount of ions in the hollow anode plasma fluctuates. In addition, the shape and volume of the main plasma change. In particular, when the volume of the main plasma changes, the overall amount (total amount) of ions in the main plasma changes even if feedback control is applied so that the density of the main plasma is constant as described above. As a result, the amount of ions incident on the surface of the workpiece changes, and the quality of the insulating coating formed on the surface of the workpiece becomes unstable. For these reasons, it is presumed that the technique disclosed in Patent Document 1 cannot stably form an insulating coating.

[0008] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a novel reactive ion plating apparatus and method capable of stably forming a high-quality insulating coating. [Means for solving the problem]

[0009] To achieve this object, the present invention includes a first invention relating to a reactive ion plating apparatus and a second invention relating to a reactive ion plating method.

[0010] The first invention is a reactive ion plating apparatus that reacts particles of an evaporation material with particles of a reactive gas to form a reaction film, which is a compound of the particles of the evaporation material and the particles of the reactive gas, on the surface of an object to be treated, and includes a vacuum chamber. The object to be treated is placed inside the vacuum chamber. The inside of the vacuum chamber is also evacuated. Furthermore, the first invention includes a container means, an evaporation means, a hot cathode, a first ionization power supply means, a thermoelectron emission amount control means, a hollow anode, a second ionization power supply means, a heater, and a bias power supply means. The container means is provided below the object to be treated inside the vacuum chamber. The container means contains an evaporation material. The evaporation means evaporates the evaporation material contained in the container means. The hot cathode is provided between the container means and the object to be treated, and emits thermoelectrons. The first ionization power supply means supplies a first ionization power to a pair of electrodes, with the container means as an anode and the hot cathode as a cathode. This first ionization power is a DC power for ionizing particles of the evaporation material evaporated by the evaporation means. The thermoelectron emission amount control means controls the amount of thermoelectrons emitted by the hot cathode so that the current component of the first ionization power is constant. The hollow anode has a hollow portion through which a reactive gas flows, and the reactive gas is introduced into the vacuum chamber through this hollow portion. The second ionization power supply means supplies a second ionization power to the pair of electrodes, with the hollow anode as the anode and the containing means as the cathode. This second ionization power is a DC power for ionizing particles of the reactive gas introduced into the vacuum chamber. The heating body is the hollow anode. The hollow anode is in electrical contact with the The heating element is provided at a discharge port for a reactive gas into the vacuum chamber in the vacuum chamber. The heating element receives an inflow of electrons in the plasma induced by the supply of the first ionizing power. by Joule heating The workpiece is heated to a temperature equal to or higher than the evaporation temperature of the particles of the evaporation material. The bias power supplying means supplies bias power to the workpiece. The bias power is power for accelerating the ionized particles of the evaporation material and the ionized particles of the reactive gas toward the surface of the workpiece.

[0011] The heating body may be, for example, a spiral body that surrounds the outlet of the hollow anode and extends spirally in the direction in which the reactive gas is discharged from the outlet.

[0012] Also, it is preferable that the heating element is detachable from the discharge port of the hollow anode.

[0013] Furthermore, it is desirable that the heater be attachable to the outlet of the hollow anode without using members such as screws for attaching the heater to the outlet.

[0014] The voltage component of the second ionization power is higher than the space potential of the plasma induced by the supply of the first ionization power, and is set to the lowest possible voltage value within a range that can heat the heating body to a temperature higher than the evaporation material of the evaporation material particles, for example, 10 V or more and 60 V or less.

[0015] Additionally, the first invention may further include an evaporation rate control means for controlling the evaporation rate of the evaporation material by the evaporation means so that the pressure inside the vacuum chamber is constant while the amount of reactive gas introduced into the vacuum chamber per unit time is constant.

[0016] The second invention of the present invention is a reactive ion plating method for forming a reaction film, which is a compound of the particles of the evaporation material and the particles of the reactive gas, on the surface of the workpiece by reacting the particles of the evaporation material with the particles of the reactive gas, and includes an evaporation step. In this evaporation step, the evaporation material contained in a container provided below the workpiece is evaporated inside a vacuum chamber in which the workpiece is placed and the inside of which is evacuated. Furthermore, the second invention includes a thermionic emission step, a first ionization power supply step, a thermionic emission amount control step, a reactive gas introduction step, a second ionization power supply step, a heater heating step, and a bias power supply step. In the thermionic emission step, thermionic electrons are emitted from a hot cathode provided between the container and the workpiece. In the first ionization power supply step, the container is used as an anode, and the hot cathode is used as a cathode, and a first ionization power is supplied to the pair of electrodes. This first ionization power is a DC power for ionizing the particles of the evaporation material evaporated in the evaporation step. In the thermoelectron emission amount control step, the amount of thermoelectrons emitted by the hot cathode is controlled so that the current component of the first ionization power is constant. In the reactive gas introduction step, a reactive gas is introduced into the vacuum chamber through a hollow portion of a hollow anode having a hollow portion through which the reactive gas flows. In the second ionization power supply step, a second ionization power is supplied to the pair of electrodes, with the hollow anode as the anode and the containing means as the cathode. This second ionization power is a DC power for ionizing particles of the reactive gas introduced into the vacuum chamber. In the heater heating step, the hollow anode The hollow anode is in electrical contact with the Electrons in a plasma induced by supplying a first ionizing power are made to flow into a heating element provided at a discharge port of a reactive gas into the inside of a vacuum chamber in the At the same time, the electrons flow into the device, generating Joule heat. In the bias power supply step, a bias power is supplied to the workpiece, and the bias power is used to accelerate the ionized particles of the evaporation material and the ionized particles of the reactive gas toward the surface of the workpiece. Effect of the Invention

[0017] According to the present invention, in the reactive ion plating apparatus and method, a high-quality insulating coating can be stably formed. Also, according to the present invention, a high-quality conductive coating can be formed. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an ion plating apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a photograph showing the appearance of the tip of a hollow anode in one embodiment of the present invention. [Diagram 3] FIG. 3 is a photograph showing the appearance of the tip of the hollow anode in one embodiment of the present invention, taken from a different angle. [Figure 4] FIG. 4 is a cross-sectional view of the tip of a hollow anode in one embodiment of the present invention. [Diagram 5] FIG. 5 is an external view of a hollow anode filament in one embodiment of the present invention. [Figure 6] FIG. 6 is a photograph showing a part of the inside of a vacuum chamber in one embodiment of the present invention. [Figure 7] FIG. 7 is a photograph showing a state of a part of the inside of a vacuum chamber when a film forming process is being performed in one embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing the conditions of an experiment in one embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing an experimental result in one embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing the analysis results by X-ray diffraction method of the yttria film formed by an experiment in one embodiment of the present invention. [Figure 11] FIG. 11 is a graph showing the hardness of an yttria film formed by an experiment in one embodiment of the present invention. [Figure 12] FIG. 12 is a diagram showing the transition of the substrate bias current when a film forming process for forming an yttria film is performed in an experiment in one embodiment of the present invention. [Figure 13]FIG. 13 is a diagram showing the transition of the hollow anode current when a film forming process for forming an yttria film is performed in an experiment in one embodiment of the present invention. [Figure 14] FIG. 14 is a diagram showing experimental conditions in another embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view of the tip of a hollow anode in another embodiment of the present invention. [Figure 16] FIG. 16 is an external view of a hollow anode filament in another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An embodiment of the present invention will be described with reference to FIGS.

[0020] The reactive ion plating apparatus 10 according to this embodiment includes a generally cylindrical vacuum chamber 12 as shown in FIG. 1. The vacuum chamber 12 is made of a metal having a relatively high mechanical strength and high corrosion resistance and heat resistance, for example, stainless steel such as SUS304. The wall of the vacuum chamber 12, that is, the vacuum chamber 12 itself, is grounded. That is, the vacuum chamber 12 itself is electrically set to a ground potential as a reference potential. The inner diameter (inner diameter) of the vacuum chamber 12 is, for example, about 700 mm. The inner height of the vacuum chamber 12 is, for example, about 1000 mm. The upper part of the vacuum chamber 12 is formed in a generally dome shape convex upwards in order to improve its mechanical strength.

[0021] Furthermore, an exhaust port 12a is provided at an appropriate position on the wall of the vacuum chamber 12, for example, on the bottom. This exhaust port 12a is connected to a vacuum pump 16 serving as an exhaust means via an exhaust pipe 14 outside the vacuum chamber 12. The vacuum pump 16 may be, for example, a diffusion pump, a turbomolecular pump, or a cryopump, but is not limited to these.

[0022] Focusing on the inside of the vacuum chamber 12, an evaporation source 18 is disposed at a position close to the bottom of the vacuum chamber 12. The evaporation source 18 has a roughly cup-shaped (more specifically, roughly cylindrical with an open top) crucible 20 as a storage means, and a 270° deflection type electron gun 22. The crucible 20 is made of, for example, copper (Cu) and stores an evaporation material 24 that is the material of the reaction film as the target object. Although not shown in detail, a hearth liner that matches the shape and dimensions of the inside of the crucible 20 is provided in the crucible 20. In practice, the evaporation material 24 is stored in the hearth liner. The hearth liner is made of, for example, tantalum (Ta), but is not limited to this, and may be made of a high melting point metal other than tantalum, such as molybdenum (Mo) or tungsten (W), or may be made of a highly heat-resistant nonmetallic material such as carbon (C). Furthermore, in the horizontal direction, the center (axis) of the crucible 20 roughly coincides with the center (axis) of the vacuum chamber 12, that is, the evaporation source 18 is disposed so that this coincides.

[0023] On the other hand, the electron gun 22 is an example of an evaporation means for heating and evaporating the evaporation material 24 contained in the crucible 20 (hearth liner), and strictly speaking, the evaporation means is configured in cooperation with an electron gun power supply device 26 provided outside the vacuum chamber 12. That is, the electron gun 22 receives power from the electron gun power supply device 26 and emits an electron beam 22a. This electron beam 22a is deflected by 270° and irradiated to the evaporation material 24 in the crucible 20. As a result, the evaporation material 24 is heated and melted, and then evaporated. The output Wg of the electron gun 22 is, for example, 10 kW at maximum. Although not shown in detail, the evaporation source 18 is provided with a water-cooling type cooling mechanism to prevent the crucible 20 from overheating. The housing of this evaporation source 18, including the crucible 20, is grounded. 1, the upper part of the evaporation source 18 is covered with an appropriate crucible cover 20a (see FIG. 6) with the opening of the crucible 20 and the emission port 18a of the electron beam 22a exposed (open) to the outside of the evaporation source 18. The crucible cover 20a is made of a high melting point metal, for example, molybdenum, and is electrically and mechanically coupled to the housing of the evaporation source 18, i.e., is grounded via the housing of the evaporation source 18.

[0024] A substrate 28 as a workpiece is placed above the evaporation source 18. The substrate 28 is held by a substrate stand 30 as a holding means with its surface, more precisely, the surface to be processed on which a reaction film is to be formed as a target, facing the evaporation source 18, particularly facing the opening of the crucible 20. The distance (in the vertical direction) between the evaporation source 18 and the surface to be processed of the substrate 28, more precisely, the distance between (the upper edge of) the opening of the crucible 20 and the surface to be processed of the substrate 28, is, for example, 250 mm to 700 mm, depending on various conditions such as the shape and dimensions of the surface to be processed of the substrate 28.

[0025] The substrate stand 30 is connected to a substrate bias power supply device 32 as a bias power supply means outside the vacuum chamber 12. The substrate bias power supply device 32 supplies the substrate bias power Wb to the substrate stand 30, and thus to the substrate 28. The substrate bias power Wb is a so-called bipolar pulse power in which the substrate bias voltage Vb, which is a voltage component of the substrate bias power Wb, alternates between a high-level voltage of a positive potential with respect to the ground potential and a low-level voltage of a negative potential with respect to the ground potential. The high-level voltage of the substrate bias voltage Vb is constant, for example, +37V with respect to the ground potential. On the other hand, the low-level voltage of the substrate bias voltage Vb can be arbitrarily changed. The average value (DC conversion value) of the substrate bias voltage Vb is adjusted by the low-level voltage, and in particular, the average value of the substrate bias voltage Vb is adjusted to a negative potential with respect to the ground potential. The average value of the substrate bias voltage Vb can be adjusted within a range of, for example, -50V to -700V. Furthermore, the frequency of the substrate bias power Wb can also be adjusted arbitrarily within a range of, for example, 50 kHz to 250 kHz. In addition, the duty ratio of the substrate bias power Wb (the ratio of the period during which the substrate bias voltage Vb is a high level voltage in one period of the substrate bias voltage Vb) can also be adjusted arbitrarily. Here, the frequency of the substrate bias power Wb is, for example, 100 kHz. And the duty ratio of the substrate bias power Wb is, for example, 20%.

[0026] Furthermore, a hot cathode filament 34 as an example of a hot cathode is disposed between the evaporation source 18 and the substrate stand 30 and close to the evaporation source 18, in other words, slightly above the opening of the crucible 20. The hot cathode filament 34 is, for example, a tungsten linear body having a diameter of 1 mm, and is provided so as to extend in the horizontal direction at a position about 10 mm to 100 mm above the opening of the crucible 20. Strictly speaking, the hot cathode filament 34 is formed in a spiral shape in order to increase the surface area thereof and to increase the amount of thermoelectrons emitted, which will be described later. The spiral diameter of the hot cathode filament 34 formed in a spiral shape is, for example, 12 mm, the number of turns is, for example, 10 (turns), and the length of the portion formed in a spiral shape is, for example, 100 mm.

[0027] Here, for example, if the mutual distance (in the vertical direction) between the opening of the crucible 20 and (the spiral center of) the hot cathode filament 34 is too short, the hot cathode filament 34 will obstruct the electron beam 22a irradiated from the electron gun 22 to the evaporation material 24, which is extremely inconvenient. On the other hand, if the mutual distance is too long, the density of the evaporated particles of the evaporation material 24 around the hot cathode filament 34, which will be described later, will decrease, making it difficult for the evaporated particles to be ionized, which is also inconvenient. For these reasons, the mutual distance is appropriately about 10 mm to 100 mm, as described above, and preferably 40 mm to 70 mm, for example 60 mm. Moreover, the hot cathode filament 34 is provided at a position slightly off-center from the center of the crucible 20 in the horizontal direction, for example about 20 mm off-center.

[0028] Both ends of the hot cathode filament 34 are connected to a hot cathode heating power supply device 36 as a hot cathode heating power supply means outside the vacuum chamber 12. The hot cathode heating power supply device 36 supplies AC hot cathode heating power Wf as hot cathode heating power to the hot cathode filament 34. Upon receiving the hot cathode heating power Wf, the hot cathode filament 34 is heated and emits thermoelectrons. The capacity of the hot cathode heating power supply device 36 is, for example, up to 2.4 kW (=40 V×60 A). The hot cathode heating power Wf may be DC power instead of AC power. In any case, it is sufficient that the hot cathode heating power supply device 36 can heat the hot cathode filament 34 to a temperature sufficient to emit thermoelectrons from the hot cathode filament 34, for example, to about 2000° C. to 2500° C. The hot cathode filament 34 is not limited to being made of tungsten, but may be made of other high melting point metals such as molybdenum and tantalum.

[0029] In addition, one end of the hot cathode filament 34 is connected to an ionization power supply 38 as a first ionization power supply means outside the vacuum chamber 12. This ionization power supply 38 supplies ionization power Wd as a first ionization power to the hot cathode filament 34. This ionization power Wd is DC power of negative potential with respect to the ground potential. In other words, the ionization power supply 38 supplies DC ionization power Wd to a pair of electrodes, the grounded evaporation source 18 being the anode and the hot cathode filament 34 being the cathode. The capacity of the ionization power supply 38 is, for example, a maximum of 9 kW (=60 V×150 A).

[0030] A current detector 40 serving as an ionization current detection means is provided between the ionization power supply 38 and ground. This current detector 40 detects the current component of the ionization power Wd, that is, the ionization current Id. The detection result of the ionization current Id by the current detector 40 is provided to a heating controller 42 serving as a thermionic emission amount control means.

[0031] The heating controller 42 controls the hot cathode heating power supply device 36 so that the ionization current Id detected by the current detector 40 becomes constant, i.e., controls the heating temperature of the hot cathode filament 34. In other words, the amount of thermoelectrons emitted by the hot cathode filament 34 is controlled so that the ionization current Id becomes constant.

[0032] Turning our attention to the inside of the vacuum chamber 12 again, the terminal portions at both ends of the hot cathode filament 34 (portions extending from both ends of the hot cathode filament 34 to the wall of the vacuum chamber 12) are covered with appropriate terminal covers 44. The terminal covers 44 are protective means for preventing the insulating coating from adhering to the terminal portions at both ends of the hot cathode filament 34 and causing abnormal discharges when forming a reaction film as the target, particularly when forming an insulating coating. The terminal covers 44 are made of a high melting point metal, such as molybdenum. Although not shown in detail, the terminal cover 44 is electrically insulated from other elements such as the vacuum chamber 12, and is in a floating state, so to speak, electrically floating.

[0033] As described later, discharge cleaning gas and reactive gas are selectively introduced into the vacuum chamber 12. A gas introduction tube, or more precisely, a tubular hollow anode 46 having the function of a gas introduction tube, is provided for this purpose. The hollow anode 46 is a so-called circular tube, that is, it has a hollow portion whose cross section perpendicular to its length direction is circular. The hollow anode 46 is provided so that one end thereof is located inside the vacuum chamber 12 as a gas outlet, and the other end thereof is located outside the vacuum chamber 12 as a gas supply inlet. As described later, a part of the one end side of the hollow anode 46 including the gas outlet, that is, a tip portion 46a, can be removed, that is, it is detachable.

[0034] The gas outlet of the hollow anode 46 is provided at a predetermined position near the opening of the crucible 20, and more precisely, at a suitable position for accelerating electrons (plasma electrons) in the plasma 100 described later toward the hollow anode 46, and thus inducing the hollow anode plasma 200 described later. However, the gas outlet of the hollow anode 46 is provided so as not to substantially come into contact (at a position where it is difficult to come into contact) with evaporated particles of the evaporation material 24 described later. This is to prevent a reaction film (strictly speaking, a substance constituting the reaction film) from adhering (accumulating) to (the inside of) the gas outlet of the hollow anode 46, causing the gas outlet to narrow.

[0035] Specifically, the gas outlet of the hollow anode 46 is provided so as to face upward. In the vertical direction, the gas outlet of the hollow anode 46 is provided at a position substantially the same as the opening of the crucible 20, or at a position higher than the opening of the crucible 20. In other words, the gas outlet of the hollow anode 46 is provided at a height position equal to or higher than the evaporation surface of the evaporation material 24 contained in the crucible 20. The distance between the gas outlet of the hollow anode 46 and the opening of the crucible 20 in the vertical direction is suitably 0 mm to 50 mm, for example, 30 mm. In the horizontal direction, the distance between the gas outlet of the hollow anode 46 and the opening of the crucible 20, specifically the distance between their centers (axes), is, for example, 140 mm, although it depends on various conditions such as the shape and dimensions of the evaporation source 18 including the crucible 20.

[0036] As described above, the tip portion 46a of the hollow anode 46 is detachable. To this end, the tip portion 46a has a male-threaded mounting portion 460 as shown in Figs. 2 to 4. A female-threaded mounted portion (not shown) corresponding to the mounting portion 460 of the tip portion 46a is provided at the portion of the hollow anode 46 to which the tip portion 46a is attached. That is, the mounting portion 460 of the tip portion 46a is screwed into the mounted portion of the hollow anode 46, thereby attaching the tip portion 46a. The tip portion 46a is removed by releasing the screwed state between the mounting portion 460 of the tip portion 46a and the mounted portion of the hollow anode 46.

[0037] FIG. 2 is an external photograph of the tip 46a, and more specifically, the tip 46a in a state where the hollow anode filament 48 described later is not attached and the tip 46a in a state where the hollow anode filament 48 is attached are taken side by side. In FIG. 2, a ruler is attached to help understand the size of the tip 46a and the hollow anode filament 48. FIG. 3 is an external photograph of the tip 46a from a different angle, and more specifically, FIG. 3(A) is an external photograph of the tip 46a in a state where the hollow anode filament 48 is not attached, and FIG. 3(B) is an external photograph of the tip 46a in a state where the hollow anode filament 48 is attached. A ruler is also attached to these FIG. 3(A) and FIG. 3(B). Furthermore, FIG. 4 is a cross-sectional view of the tip 46a, and more specifically, a cross-sectional view taken along a plane including the central axis of the tip 46a.

[0038] In particular, referring to FIG. 4, the diameter (inner diameter) Da of the hollow portion 462 of the tip portion 46a varies in the central axis direction of the tip portion. For example, the diameter Db of the hollow portion 462 on the attachment portion 460 side of the tip portion 46a is smaller than the diameter Da' of the hollow portion 462 near the center in the central axis direction of the tip portion 46a. This is due to a trade-off with the diameter (outer diameter: thread diameter (nominal diameter)) Dc of the attachment portion 460. In contrast, the diameter Dd of the hollow portion 462 on the opposite side of the attachment portion 460 side of the tip portion 46a, that is, on the gas discharge port side, is larger than the diameter Da' of the hollow portion 462 near the center in the central axis direction of the tip portion 46a. This is also to prevent a reaction film from adhering to the gas discharge port, causing the gas discharge port to narrow.

[0039] As an example, the diameter Da' of the hollow portion 462 near the center in the central axis direction of the tip portion 46a is 4 mm. The diameter Db of the hollow portion 462 on the attachment portion 460 side of the tip portion 46a is 2 mm, and the diameter Dc of the attachment portion 460 is 6 mm (M6). The diameter Dd of the hollow portion 462 on the gas discharge port side of the tip portion 46a is 7 mm. Furthermore, the diameter (outer diameter) De of the tip portion 46a is 12 mm. In addition, the dimension of the tip portion 46a in the central axis direction of the tip portion 46a, that is, the length dimension La, is 70 mm, and the length dimension Lb of the attachment portion 460 is 10 mm. The length dimension Lc of the portion of the hollow portion 462 of the tip portion 46a with the small diameter Db is 15 mm, and the length dimension Ld of the portion of the hollow portion 462 with the large diameter Dd is 5 mm. These dimensional values ​​are merely examples and are not limiting.

[0040] The tip 46a is made of a high melting point metal, such as tantalum, which is relatively easy to process, and the rest of the hollow anode 46 except for the tip 46a is made of a highly corrosion-resistant and heat-resistant metal, such as stainless steel, such as SUS304.

[0041] Furthermore, a hollow anode filament 48 as an example of a heating body as shown in Fig. 5 is attached to the tip portion 46a. The hollow anode filament 48 is, for example, a tungsten spiral (coil) body, and more specifically, a tungsten wire having a diameter (wire diameter) ds of 1 mm formed into a spiral shape. The spiral diameter Ds of the hollow anode filament 48 is slightly smaller than the diameter De of the tip portion 46a, for example, 11.5 mm. The number of turns of the hollow anode filament 48 is, for example, 8 (turns), and the length dimension Ls of the hollow anode filament 48 is smaller than the length dimension La of the tip portion 46a, for example, 25 mm.

[0042] As shown in FIG. 2 and FIG. 3(B), the hollow anode filament 48 is attached to the gas outlet side of the tip portion 46a. Specifically, the hollow anode filament 48 is attached so as to surround the periphery of the gas outlet of the tip portion 46a and extend in the gas discharge direction from the gas outlet, in other words, to extend along the central axis direction of the tip portion 46a. At this time, the hollow anode filament 48 is attached to the tip portion 46a in a state in which the spiral diameter Ds on the side attached to the tip portion 46a is slightly widened by manual work (external force). Then, after the hollow anode filament 48 is attached to the tip portion 46a, the hollow anode filament 48 is fixed to the tip portion 46a so as to tighten the outer periphery of the tip portion 46a by its elasticity. In short, the hollow anode filament 48 is fixed to the tip portion 46a without using a fixing member such as a screw for fixing it to the tip portion 46a. Naturally, the hollow anode filament 48 can be removed from the tip portion 46a, that is, it can be attached to and detached from the tip portion 46a. Note that a part of the hollow anode filament 48, for example, a portion not greater than half of its length dimension Ls, more specifically, a portion of about three turns, is attached so as to surround the periphery of the gas discharge port side of the tip portion 46a.

[0043] Fig. 6 is a photograph of a portion including the crucible 20, the hot cathode filament 34, the tip 46a of the hollow anode 46, and the hollow anode filament 48 in the vacuum chamber 12. The lower left side in Fig. 6 corresponds to the front side of the reactive ion plating apparatus 10, and the upper right side in Fig. 6 corresponds to the rear side of the reactive ion plating apparatus 10. The upper left side in Fig. 6 corresponds to the left side of the reactive ion plating apparatus 10, and the lower right side in Fig. 6 corresponds to the right side of the reactive ion plating apparatus 10.

[0044] As shown in FIG. 6, the hot cathode filament 34 is provided so as to extend along the left-right direction of the reactive ion plating device 10. The hot cathode filament 34 is provided in a position slightly offset from the center of the crucible 20 toward the front side of the reactive ion plating device 10 in the horizontal direction, and more specifically, is provided at a position about 20 mm away from the center of the crucible 20 as described above. The tip 46a of the hollow anode 46 is provided at a position on the rear side of the reactive ion plating device 10 relative to the crucible 20 and the hot cathode filament 34. In addition, a hollow anode filament 48 is attached to the tip 46a of the hollow anode 46. In FIG. 6, yttrium (Y) as the evaporation material 24 is contained in the crucible 20, and strictly speaking, the yttrium contained in the crucible 20 is once melted and then cooled and solidified.

[0045] 1 again, the gas supply inlet (the other end) of the hollow anode 46 is connected to respective supply sources (not shown) of the discharge cleaning gas and the reactive gas outside the vacuum chamber 12. Specifically, each supply source is connected to the gas supply inlet of the hollow anode 46 via appropriate piping (not shown). Each piping is provided with a mass flow controller (not shown) as a flow rate control means for controlling the flow rate Q of the gas flowing through the piping, and an opening / closing valve (not shown) as an opening / closing means for opening and closing the inside of the piping.

[0046] Additionally, the hollow anode 46 is connected to a hollow anode power supply device 50 serving as second ionization power supply means outside the vacuum chamber 12. The hollow anode power supply device 50 supplies hollow anode power Wh as second ionization power to the hollow anode 46. This hollow anode power Wh is DC power of positive potential with respect to the ground potential. In other words, the hollow anode power supply device 50 supplies DC hollow anode power Wh to a pair of electrodes, the hollow anode 46 being the anode and the grounded evaporation source 18 being the cathode. The capacity of the hollow anode power supply device 50 is, for example, a maximum of 3 kW (=60 V×50 A).

[0047] In addition, a pressure gauge 52 is provided at an appropriate position in the vacuum chamber 12 as a pressure measuring means for measuring the pressure P in the vacuum chamber 12, and more precisely, a gauge portion (measurement portion) 52a of the pressure gauge 52 is provided. The main body of the pressure gauge 52 is provided outside the vacuum chamber 12. For example, a Penning vacuum gauge is used as the pressure gauge 52, but the present invention is not limited to this, and a gauge portion other than the Penning vacuum gauge, such as an ionization vacuum gauge, may be used. In addition, in FIG. 1, the gauge portion 52a of the pressure gauge 52 is provided near the substrate stand 30, but in reality, the gauge portion 52a is provided at a position where it is less affected by the adhesion of evaporated particles of the evaporation material 24 described later, for example, near the exhaust port 12a.

[0048] The measurement result of the pressure P by the pressure gauge 52 is provided to an evaporation rate controller 54 located outside the vacuum chamber 12. The evaporation rate controller 54 controls the output Wg of the electron gun 22 via the electron gun power supply device 26 so that the pressure P inside the vacuum chamber 12 measured by the pressure gauge 52 becomes constant, that is, it controls the evaporation rate, which is the amount of evaporation of the evaporation material 24 per unit time.

[0049] Furthermore, a shutter 56 is provided between the hot cathode filament 34 and the substrate stand 30 in the vacuum chamber 12, preferably at a position close to the hot cathode filament 34. The shutter 56 selectively transitions between an open state in which the surface to be processed of the substrate 28 is exposed to the opening of the crucible 20 and a closed state in which the surface to be processed of the substrate 28 is shielded from the opening of the crucible 20 by a shutter drive mechanism (not shown). The shutter 56 is made of a non-magnetic metal that has relatively high mechanical strength, high corrosion resistance, and high heat resistance, and is made of stainless steel such as SUS304. The shutter 56 is electrically insulated from other elements such as the vacuum chamber 12, that is, it is in an electrically floating state. The distance between the shutter 56 (its lower surface) and the opening of the crucible 20 in the vertical direction is, for example, about 100 mm.

[0050] Although not shown, a suitable heater is provided at an appropriate position in the vacuum chamber 12 as a heating means for heating the substrate 28. Examples of such a heater include a carbon heater, a lamp heater, a sheath heater, and a ceramic heater. The heater receives a supply of heater heating power from a heater heating power supply device located outside the vacuum chamber 12, thereby appropriately heating the substrate 28.

[0051] The reactive ion plating apparatus 10 according to this embodiment having such a configuration is different from the so-called conventional technology disclosed in the above-mentioned Patent Document 1 in that a hollow anode filament 48 is provided. As described above, the conventional technology cannot stably form an insulating coating, but the reactive ion plating apparatus 10 according to this embodiment has an extremely beneficial effect of being able to stably form the insulating coating. That is, by providing the hollow anode filament 48 to the conventional technology, that is, by simply adding an extremely simple and inexpensive configuration of providing the hollow anode filament 48 to the conventional technology, an extremely beneficial effect of being able to stably form an insulating coating is achieved.

[0052] To explain this in detail, a configuration in which the hollow anode filament 48 is removed from the reactive ion plating apparatus 10 according to this embodiment is prepared as a conventional technique. First, a case in which an yttria (yttrium oxide: Y2O3) film, which is one of insulating films, is formed by this conventional technique will be described.

[0053] As mentioned above, Fig. 2 is a photograph showing the tip 46a of the hollow anode 46 in a state where the hollow anode filament 48 is not attached and the tip 46a of the hollow anode 46 in a state where the hollow anode filament 48 is attached, side by side, and the tip 46a of the hollow anode 46 in a state where the hollow anode filament 48 is not attached is, in other words, the tip 46a of the hollow anode 46 in the prior art. And it can be said that the tip 46a of the hollow anode 46 in a state where the hollow anode filament 48 in Fig. 2 is attached is the tip 46a of the hollow anode 46 in this embodiment. Similarly, it can be said that the tip 46a of the hollow anode 46 in the state where the hollow anode filament 48 is not attached as shown in Figure 3(A) is the tip 46a of the hollow anode 46 in the prior art, and the tip 46a of the hollow anode 46 in the state where the hollow anode filament 48 is attached as shown in Figure 3(B) is the tip 46a of the hollow anode 46 in this embodiment.

[0054] Now, when forming an yttria film by the conventional technique, high purity yttrium is placed in the crucible 20 as the evaporation material 24 which is the material of the yttria film. The yttrium as the evaporation material 24 is, for example, a granular body having a diameter of about 3 mm to 5 mm, but is not limited thereto. In addition, the substrate 28 is attached to the substrate stand 30. Then, the inside of the vacuum chamber 12 is closed.

[0055] The vacuum chamber 12 is then pumped to a vacuum of 1×10 -3 The pressure is evacuated to a pressure P of about 10 Pa, and a so-called vacuum is drawn. At the same time as this vacuum drawing, a heat treatment is performed to heat the substrate 28 by the heater described above, and the substrate 28 is heated to, for example, about 200° C. During this vacuum drawing and heat treatment, the shutter 56 is kept closed, including for the purpose of protecting the evaporation material 24 in the crucible 20 (from contaminants, etc.).

[0056] After the evacuation and heat treatment are performed for a predetermined time, for example, 2 hours, a discharge cleaning process is performed to clean the surface to be treated of the substrate 28. Specifically, with the shutter 56 closed, argon (Ar) gas and hydrogen (H2) gas as discharge cleaning gases are simultaneously introduced into the vacuum chamber 12, more specifically, through the hollow portion of the hollow anode 46. Then, the pressure P in the vacuum chamber 12 is increased to, for example, 7×10 -2 The partial pressure of argon gas is kept below 1.5×10 Pa. -2 Pa, and the partial pressure of hydrogen gas is 5.5×10 -2 The hot cathode filament 34 is heated to a voltage of Pa. Furthermore, a hot cathode heating power Wf is supplied to the hot cathode filament 34. This heats the hot cathode filament 34, causing the hot cathode filament 34 to emit thermoelectrons. At the same time, an ionization power Wd is supplied to the hot cathode filament 34. That is, the hot cathode filament 34 serves as a cathode, and the evaporation source 18 serves as an anode, and a direct current ionization power Wd is supplied to this pair of electrodes.

[0057] Then, thermoelectrons emitted from the hot cathode filament 34 as a cathode are accelerated toward the evaporation source 18 as an anode, particularly toward the crucible 20 located near the hot cathode filament 34. The accelerated thermoelectrons collide inelastically with the particles (atoms or molecules) of the argon gas and the hydrogen gas. As a result, the particles of the argon gas and the hydrogen gas are ionized, and argon ions and hydrogen ions are generated. Furthermore, with this ionization, electrons are ejected from the particles (outermost shells) of the argon gas and the hydrogen gas, and the ejected electrons flow into the crucible 20 as the anode. As this phenomenon continues, a plasma 100 containing argon ions and hydrogen ions is induced. The mode of this plasma 100 is a low-voltage, high-current arc discharge. The introduction of the argon gas and the hydrogen gas into the vacuum chamber 12 may not be started simultaneously, but may be started separately (at different times).

[0058] At this time, the ionization voltage Vd, which is a voltage component of the ionization power Wd, is set to an appropriate constant value. In addition, the hot cathode heating power Wf is controlled so that the ionization current Id, which is a current component of the ionization power Wd, becomes an appropriate constant value, that is, the amount of thermoelectrons emitted by the hot cathode filament 34 is controlled. The ionization current Id represents a current flowing into the crucible 20 as the anode, that is, is proportional to the amount of ions (argon ions and hydrogen ions in this case) in the plasma 100, in other words, is proportional to the density of the plasma 100. In short, the amount of thermoelectrons emitted by the hot cathode filament 34 is controlled so that the density of the plasma 100 is constant, and so-called feedback control is applied.

[0059] In addition, hollow anode power Wh is supplied to the hollow anode 46. That is, a pair of electrodes, the hollow anode 46 being the anode and the evaporation source 18 being the cathode, is supplied with a direct current hollow anode power Wh. This accelerates electrons in the plasma 100 toward the hollow anode 46, particularly toward the gas outlet (at the tip 46a) of the hollow anode 46 located close to the plasma 100. The accelerated electrons collide inelastically with the particles of argon gas and hydrogen gas discharged from the gas outlet of the hollow anode 46. As a result, the particles of argon gas and hydrogen gas are actively (efficiently) ionized even in the vicinity of the gas outlet of the hollow anode 46, so that a hollow anode plasma 200 is induced. In the vicinity of the gas outlet of the hollow anode 46, the pressures of the argon gas and hydrogen gas are high, that is, the densities of the particles of the argon gas and hydrogen gas are high, and therefore a high-density hollow anode plasma 200 is induced. This embodiment of the hollow anode plasma 200 is also a low-voltage, high-current arc discharge.

[0060] Most of the electrons that contribute to the induction of the hollow anode plasma 200 are plasma electrons among the electrons in the so-called main plasma 100 induced by the supply of the ionizing power Wd. In other words, the thermoelectrons emitted from the hot cathode filament 34 do not contribute to the induction of the hollow anode plasma 200. This is considered to be due to the large mutual distance between the hot cathode filament 34 and the gas outlet port of the hollow anode 46. As evidence of this, it has been confirmed that even when the hot cathode heating power Wf is supplied to the hot cathode filament 34 and the hollow anode power Wh is supplied to the hollow anode 46, the main plasma 100 is not induced and the hollow anode plasma 200 is not induced when the ionizing power Wd is not supplied.

[0061] In this manner, while the main plasma 100 and the hollow anode plasma 200 are induced, the substrate bias power Wb is further supplied to the substrate 28. More specifically, the substrate bias power Wb is supplied such that the average value of the substrate bias voltage Vb is negative with respect to the ground potential, for example, −600 V. Then, the shutter 56 is opened. Then, the argon ions and hydrogen ions in the main plasma 100 and the hollow anode plasma 200 are accelerated toward the surface of the substrate 28 to be processed and are incident on the surface of the substrate 28 to be processed. As a result, the surface of the substrate 28 to be processed is cleaned by a sputtering (bombardment) action caused by the argon ions colliding with the surface of the substrate 28 to be processed, and a chemical reaction (reduction) action caused by the hydrogen ions chemically reacting with impurities such as organic contaminants and oxide films adhering to the surface of the substrate 28 to be processed.

[0062] This discharge cleaning process is performed until the cleaning level of the processing surface of the substrate 28 reaches a desired level. After this discharge cleaning process is completed, the shutter 56 is closed. At the same time, the introduction of argon gas and hydrogen gas into the vacuum chamber 12 is stopped. This causes the main plasma 100 and the hollow anode plasma 200 to disappear temporarily. Then, a film formation process is performed to form an yttria film as the target on the processing surface of the substrate 28.

[0063] In this film formation process, oxygen (O2) gas as a reactive gas is introduced into the vacuum chamber 12. Then, the pressure P in the vacuum chamber 12 is set to, for example, 0.1 Pa (=1×10 -1 The pressure of the evaporation source 18 is maintained at or below 100 Pa. Furthermore, the electron gun 22 of the evaporation source 18 is energized. As a result, an electron beam 22a is emitted from the electron gun 22, and the electron beam 22a is irradiated onto the evaporation material 24 in the crucible 20. The evaporation material 24 is heated and melted by the irradiation of the electron beam 22a, and further evaporated. At this time, the hot cathode filament 34 is supplied with the hot cathode heating power Wf and the ionization power Wd. Therefore, similar to the discharge cleaning process described above, the thermoelectrons emitted from the hot cathode filament 34 are accelerated toward the crucible 20 as the anode (and the yttrium as the melted evaporation material 24 in the crucible 20). Then, the accelerated electrons inelastically collide with the evaporated particles of the evaporation material 24, so-called evaporation particles. As a result, the evaporated particles of the evaporation material 24 are ionized, and yttrium ions are generated. Furthermore, as a result of this ionization, electrons are ejected from (the outermost shell of) the evaporated particles of the evaporation material 24, and these ejected electrons flow into the crucible 20, which serves as the anode. In parallel with this, the electrons accelerated from the hot cathode filament 34 toward the crucible 20 also collide inelastically with the oxygen gas particles. As a result, the oxygen gas particles are also ionized, and oxygen ions are generated. Furthermore, as a result of this ionization of the oxygen gas particles, electrons are ejected from the oxygen gas particles, and these ejected electrons also flow into the crucible 20. As this phenomenon continues, the main plasma 100 is induced again by the arc discharge.

[0064] In this case, the ionization voltage Vd, which is a voltage component of the ionization power Wd, is set to an appropriate constant value. At the same time, the hot cathode heating power Wf is controlled so that the ionization current Id, which is a current component of the ionization power Wd, becomes an appropriate constant value. Furthermore, the substrate bias power Wb is adjusted so that the average value of the substrate bias voltage Vb, which is a voltage component of the substrate bias power Wb, becomes an appropriate negative value with respect to the ground potential.

[0065] Moreover, hollow anode power Wh is being supplied to the hollow anode 46. Therefore, similarly to the discharge cleaning process described above, electrons in the main plasma 100 are accelerated toward the gas outlet of the hollow anode 46. These accelerated electrons inelastically collide with oxygen gas particles discharged from the gas outlet of the hollow anode 46. As a result, oxygen gas particles are actively (concentratedly) ionized also in the vicinity of the gas outlet of the hollow anode 46, and hollow anode plasma 200 is induced again by arc discharge.

[0066] In this manner, with the main plasma 100 and the hollow anode plasma 200 induced once again, the shutter 56 is opened. Then, the ions in the main plasma 100 and the hollow anode plasma 200 are accelerated toward the processing surface of the substrate 28 and are incident on the processing surface of the substrate 28. As a result, an yttria film, which is a compound of yttrium particles containing yttrium ions and oxygen particles containing oxygen ions, is formed on the processing surface of the substrate 28.

[0067] In addition, in this film formation process, the flow rate Q of the reactive gas introduced into the vacuum chamber 12 is kept constant. Then, the output Wg of the electron gun 22 is controlled so that the pressure P in the vacuum chamber 12 is kept constant, that is, the evaporation rate of the evaporation material 24 is controlled. Such control is derived from a stoichiometric viewpoint, and the details are disclosed in Patent Document 1. Then, by carrying out this control, the formation rate of the yttria film, that is, the film formation rate, is stabilized. That is, the film formation rate is stabilized without using a dedicated means for monitoring the film formation rate, such as a film thickness monitor.

[0068] This film formation process is performed until an yttria film having a desired thickness is formed. After the film formation process is completed, the shutter 56 is closed. Then, the power supply to the electron gun 22 is stopped. At the same time, the introduction of oxygen gas into the vacuum chamber 12 is stopped. Furthermore, the supply of the substrate bias power Wb to the substrate 28 is stopped. In addition, the supply of the hot cathode heating power Wf to the hot cathode filament 34 is stopped, and the supply of the ionization power Wd to the hot cathode filament 34 is stopped. Then, the supply of the hollow anode power Wh to the hollow anode 46 is stopped. As a result, the main plasma 100 and the hollow anode plasma 200 are extinguished.

[0069] Then, the vacuum chamber 12 is evacuated again, and after a suitable cooling period of about 30 minutes is allowed to stand in this state, the pressure in the vacuum chamber 12 is gradually returned to atmospheric pressure. Then, the vacuum chamber 12 is opened, and the substrate 28 is removed from the vacuum chamber 12. This completes a series of processes including the film formation process for forming the yttria film.

[0070] In this manner, the yttria film is formed, but in the conventional technology, an insulating coating called the yttria film adheres to the hollow anode 46, particularly around the gas outlet of the hollow anode 46 (at the tip 46a), which reduces the function of the hollow anode 46 as an anode. Then, the number of electrons moving from the main plasma 100 toward the hollow anode 46 decreases, the hollow anode plasma 200 becomes unstable, and the amount of ions in the hollow anode plasma 200 fluctuates, specifically decreases. In addition, the decrease in the number of electrons moving from the main plasma 100 toward the hollow anode 46 changes the shape and volume of the main plasma 100, particularly decreasing the volume. When the volume of the main plasma 100 decreases, the overall amount (total amount) of ions in the main plasma 100 decreases, even if feedback control is applied so that the density of the main plasma 100 is constant as described above. As a result, the amount of ions incident on the processing surface of the substrate 28 decreases, and the quality of the yttria film formed on the surface of the substrate 28 decreases, that is, the film becomes unstable. For these reasons, it is presumed that the conventional technology is unable to stably form an insulating film such as an yttria film.

[0071] In the conventional technology, the thermoelectrons emitted from the hot cathode filament 34 are accelerated toward the crucible 20 as an anode in order to induce the main plasma 100, as described above. Strictly speaking, the thermoelectrons are accelerated not only to the crucible 20 but also to an appropriate location at ground potential, for example, the crucible cover 20a. That is, the crucible cover 20a also functions as an anode for inducing the main plasma 100. However, when a film forming process for forming an insulating coating is performed, the insulating coating is also attached to the crucible cover 20a, and the function of the crucible cover 20a as an anode is reduced. This causes the shape and volume of the main plasma 100 to change, and in particular, the volume of the main plasma 100 becomes smaller. As a result, the amount of ions incident on the processed surface of the substrate 28 decreases, that is, the amount of the ions becomes unstable. This is also presumed to be one of the reasons why the insulating coating cannot be formed stably.

[0072] On the other hand, when forming an insulating film by the reactive ion plating apparatus 10 according to this embodiment, a series of processes including the film forming process are performed in the same manner as in the conventional technology, but the insulating film can be stably formed by the reactive ion plating apparatus 10 according to this embodiment. That is, by simply adding an extremely simple and inexpensive configuration in which the hollow anode filament 48 is attached to the hollow anode 46 (the tip 46a), it becomes possible to stably form the insulating film.

[0073] Specifically, when a film formation process for forming an insulating coating is performed by the reactive ion plating apparatus 10 according to this embodiment, the main plasma 100 and the hollow anode plasma 200 are induced, as in the conventional technology. In particular, the hollow anode plasma 200 is induced when electrons in the main plasma 100 are accelerated toward the gas outlet of the hollow anode 46 and inelastically collide with particles of the reactive gas discharged from the gas outlet of the hollow anode 46.

[0074] Here, the hollow anode filament 48 is attached to the hollow anode 46 as described above. The hollow anode filament 48 is made of tungsten, a high melting point metal, and is electrically connected to the hollow anode 46, i.e., functions as a part of the hollow anode 46. Therefore, electrons accelerated from the main plasma 100 toward the gas outlet of the hollow anode 46 also flow into the hollow anode filament 48. The hollow anode filament 48 is a helical body, which means that its surface area is enlarged and its shape is easy to capture electrons accelerated toward the hollow anode filament 48. Moreover, the hollow anode filament 48 has a diameter ds of 1 mm, so that its heat capacity is small. For these reasons, the hollow anode filament 48 is heated (self-heated) by Joule heat when electrons flow in from the main plasma 100. The heating temperature of the hollow anode filament 48 is estimated to be close to 2000°C.

[0075] FIG. 7 is a photograph of a part of the vacuum chamber 12 during a film-forming process for forming an yttria film as an insulating coating, specifically, a part including the crucible 20, the hot cathode filament 34, the tip 46a of the hollow anode 46, and the hollow anode filament 48. As shown in FIG. 7, the hollow anode filament 48 is red-hot, and from the red-hot state, it is estimated that the hollow anode filament 48 is heated to nearly 2000° C. In FIG. 7, the light white part with a slight purple tint is the main plasma 100. Although it is difficult to see from FIG. 7, the part surrounded by the hollow anode filament 48 is light white, which is the hollow anode plasma 200 (however, in FIG. 7, the reference number "200" representing the hollow anode plasma 200 is omitted for ease of viewing).

[0076] In this way, the hollow anode filament 48 is heated to nearly 2000°C, which is equal to or higher than the evaporation temperature of various materials commonly used as the evaporation material 24, including yttrium, in other words, equal to or higher than the evaporation temperature of the particles (evaporation particles and their ions) of the evaporation material 24. Therefore, when a film forming process is performed to form an insulating coating, the particles of the evaporation material 24 adhere to the surface of the hollow anode filament 48, but the particles adhered to the surface of the hollow anode filament 48 are re-evaporated by heating the hollow anode filament 48 to a temperature equal to or higher than the evaporation temperature. Therefore, no insulating coating is attached to the surface of the hollow anode filament 48, and as a result, the hollow anode filament 48 maintains its function as a part of the hollow anode 46. In short, even if an insulating coating is attached to the hollow anode 46 itself, such as the gas outlet of the hollow anode 46, the hollow anode filament 48 functions as a stable anode.

[0077] In this way, the hollow anode filament 48 functions as a stable anode, and thus the amount of electrons flowing from the main plasma 100 into the hollow anode filament 48 is stabilized. This stabilizes the hollow anode plasma 200, that is, the amount of ions in the hollow anode plasma 200. In addition, the amount of electrons flowing from the main plasma 100 into the hollow anode filament 48 is stabilized, and thus the shape and volume of the main plasma 100 are stabilized, in other words, the total amount of ions in the main plasma 100 is stabilized. As a result, the amount of ions incident on the processing surface of the substrate 28 is stabilized, and thus the quality of the insulating coating formed on the surface of the substrate 28 is stabilized. For this reason, according to this embodiment, it is possible to stably form an insulating coating.

[0078] Strictly speaking, the heating temperature of the hollow anode filament 48 also depends on the hollow anode voltage Vh, which is a voltage component of the hollow anode power Wh. For example, the higher the hollow anode voltage Vh, the higher the heating temperature of the hollow anode filament 48. On the other hand, the hollow anode voltage Vh is the space potential of the hollow anode plasma 200 itself, and therefore, the higher the hollow anode voltage Vh, the higher the space potential of the hollow anode plasma 200. If the hollow anode voltage Vh is excessively high, abnormal discharge is likely to occur. Incidentally, it has been found from experience that abnormal discharge is likely to occur when the space potential of the hollow anode plasma 200 exceeds 60V. Therefore, it is essential that the hollow anode voltage Vh is set to a value as low as possible within a range in which the hollow anode filament 48 can be heated to the evaporation temperature of the evaporation material 24 or higher, for example, 60V or less. Moreover, in order to accelerate the electrons in the main plasma 100 toward the hollow anode 46, the hollow anode voltage Vh needs to be higher than the space potential of the main plasma 100. Incidentally, the space potential of the main plasma 100 is generally about 5V to 8V under any conditions, that is, lower than 10V. Therefore, it is essential that the hollow anode voltage Vh is set to, for example, 10V or higher. For these reasons, the hollow anode voltage Vh is appropriately set within the range of 10V or higher and 60V or lower depending on various conditions such as the type of evaporation material 24.

[0079] Furthermore, as described above, in the conventional technology, the shape and volume of the main plasma 100 change due to the adhesion of an insulating film to the crucible cover 20a, which is also presumed to be one of the reasons why the insulating film cannot be stably formed as the target object. However, in this embodiment, an insulating film also adheres to the crucible cover 20a. However, in this embodiment, the hollow anode filament 48 functions as a stable anode, so that the hollow anode plasma 200 is stabilized, and the shape and volume of the main plasma 100 are stabilized. This state is stably maintained regardless of whether an insulating film is attached to the crucible cover 20a. Therefore, according to this embodiment, regardless of whether an insulating film is attached to the crucible cover 20a, the shape and volume of the main plasma 100 are stabilized, and thus the insulating film can be stably formed as the target object.

[0080] As described above, according to this embodiment, the insulating coating can be stably formed. In order to verify this, the following experiment was carried out.

[0081] That is, in addition to this embodiment and the conventional technology, a configuration in which the hollow anode voltage Vh, which is a voltage component of the hollow anode power Wh, is set to 0 V, that is, a configuration in which the hollow anode power Wh is not supplied, is prepared as a reference technology. Then, an yttria film was actually formed as an insulating coating by each of this embodiment, the reference technology, and the conventional technology, and the properties of the films were compared. The film formation conditions in this experiment are shown in FIG. 8. The experimental results are shown in FIG. 9.

[0082] As shown in FIG. 8, in this experiment, the flow rate Q[O2] of oxygen gas as a reactive gas introduced into the vacuum chamber 12 was set to 100 mL / min. In addition, the pressure P in the vacuum chamber 12 was set to 0.015 Pa, and strictly speaking, the output Wg of the electron gun 22 was controlled so that the pressure P in the vacuum chamber 12 was constant at 0.015 Pa. By this control, the output Wg of the electron gun 22 fluctuated in the range of 2.52 kW to 2.70 kW, and more specifically, the emission current Ig fluctuated in the range of 280 mA to 300 mA with the acceleration voltage Vg of the electron gun 22 being constant at 9 kV. Furthermore, the ionization power Wd was set to a constant of 250 W, and more specifically, the hot cathode heating power Wf was controlled so that the ionization current Id was constant at 10 A with the ionization voltage Vd being constant at 25 V. The hollow anode voltage Vh was set to 0V or 30V, specifically, 30V in the present embodiment and the conventional technology, and 0V in the reference technology. The substrate bias voltage Vb (average value) was set to -600V. The frequency of the substrate bias voltage Vb was 100kHz, and the duty ratio was 20%. The deposition time was set to 45min.

[0083] In this experiment, the substrate stand 30 was a disk stand with a diameter of 360 mm and a thickness of 3 mm. The distance between the opening of the crucible 20 and the surface of the substrate 28 to be processed was 450 mm. The diameter of the opening of the crucible 20 was 60 mm. A tungsten hearth liner with a weight of 73 g was set in the crucible 20, and about 112 g of yttrium was filled in the hearth liner.

[0084] 9 showing the results of this experiment, for example, when focusing on the film thickness, the film thickness (4.96 μm) of the yttria film formed by this embodiment is obviously smaller than the film thickness (6.61 μm and 6.50 μm) of the yttria film formed by the reference technology and the conventional technology, respectively. From another perspective, when focusing on the film formation speed, the film formation speed (6.61 μm / h) in this embodiment is obviously smaller than the film formation speed (8.81 μm / h and 8.67 μm / h) in the reference technology and the conventional technology, respectively. This means that the yttria film formed by this embodiment is denser and has a higher hardness than the yttria films formed by the reference technology and the conventional technology, respectively.

[0085] As proof, the crystal structure of the yttria film formed by this experiment was analyzed by X-ray diffraction (XRD), and the results shown in FIG. 10 were obtained. As shown in FIG. 10, the yttria films formed by the reference technique (thick short dashed line) and the conventional technique (thick long dashed line) each show a large peak in the plane orientation (222), that is, they are preferentially oriented. In contrast, the yttria film formed by this embodiment (thick solid line) shows peaks in two plane orientations (222) and (440), and the magnitudes (intensities) of these peaks are approximately the same, and in particular, the peak in the plane orientation (222) is about 0.1 to 0.2 times larger than the peak of the yttria films formed by the reference technique and the conventional technique. From this, it is presumed that the yttria film formed by this embodiment is microcrystalline (amorphous), and therefore dense. In addition, in the analysis results shown in FIG. 10, a peak representing SUS304 is also seen, but this is because the substrate 28 used for analysis is SUS304.

[0086] Referring again to Fig. 9, when paying attention to the Knoop hardness, the Knoop hardness of the yttria film formed by this embodiment is clearly higher than that of the yttria film formed by the reference technology and the conventional technology, regardless of whether the indenter load is 200 g, 100 g, 50 g, or 25 g. Fig. 11 shows the Knoop hardness in a graph, and from Fig. 11 it can be intuitively understood that the present embodiment (thick solid line with a circle) forms a harder yttria film than either the reference technology (thick short dashed line with a square) or the conventional technology (thick long dashed line with a triangle).

[0087] Referring again to FIG. 9, focusing on the internal stress, the internal stress of the yttria film formed by this embodiment (-2.81 GPa) is clearly greater in absolute value than the internal stresses of the yttria films formed by the reference technology and the conventional technology (-1.21 GPa and -1.21 GPa). When this internal stress is a negative value, it indicates that the internal stress is compressive stress, and the greater the absolute value, the greater the compressive stress and the higher the hardness. Therefore, it can be seen from this internal stress that the yttria film formed by this embodiment is harder than the yttria films formed by the reference technology and the conventional technology.

[0088] 12 shows the transition of the substrate bias current Ib, which is the current component of the substrate bias power Wb during the deposition process for forming the yttria film. The substrate bias current Ib is correlated (proportional) to the amount of ions incident on the substrate table 30, that is, correlated (proportional) to the amount of ions incident on the processing surface of the substrate 28.

[0089] As shown in FIG. 12, for example, in the case of the conventional technology (thick long broken line with triangle mark), at the beginning of the film formation process, the substrate bias current Ib is large, so to speak, at the expected value, and therefore the expected amount of ions is incident on the surface of the substrate 28 to be processed. However, as the film formation process progresses, particularly after about 15 minutes have passed since the start of the film formation process, the substrate bias current Ib begins to decrease, that is, the amount of ions incident on the surface of the substrate 28 to be processed begins to decrease. As described above, this is presumably due to the fact that an insulating film adheres to the periphery of the gas discharge port of the hollow anode 46, thereby reducing the function of the hollow anode 46 as an anode. Another presumably cause of this is the adhesion of an insulating film to the crucible cover 20a. Then, after about 25 minutes have passed since the start of the film formation process, the substrate bias current Ib settles down somewhat, but its value is about 2 / 3 of the value at the beginning of the film formation process. Thus, in the conventional technology, it is presumed that the substrate bias current Ib is unstable, i.e., the amount of ions incident on the processing surface of the substrate 28 fluctuates, making it impossible to stably form an insulating coating.

[0090] Similarly, in the reference technique (thick short dashed line with square mark), the substrate bias current Ib is large at the beginning of the film formation process, which is the expected value, but as the film formation process progresses, the substrate bias current Ib decreases. Then, after about 20 minutes have passed since the start of the film formation process, the substrate bias current Ib settles down somewhat, but the value is about 2 / 3 of the value at the beginning of the film formation process. That is, in the reference technique, the substrate bias current Ib is unstable, that is, the amount of ions incident on the processing surface of the substrate 28 is unstable. As described above, in the reference technique, the hollow anode power Wh is not supplied, so the hollow anode 46 does not function as an anode (it functions only as a gas introduction tube), and the hollow anode filament 48 does not glow red. Therefore, it is presumed that the substrate bias current Ib becomes unstable due to the adhesion of an insulating coating to the crucible cover 20a. And, in such a reference technique, an insulating coating cannot be stably formed.

[0091] In contrast, in this embodiment (bold solid line with circles), the substrate bias current Ib is stable and maintains the desired value from the start to the end of the film formation process. That is, the amount of ions incident on the processing surface of the substrate 28 is stable. It is therefore presumed that this embodiment allows the insulating coating to be stably formed.

[0092] 13 shows the transition of the hollow anode current Ih, which is a current component of the hollow anode power Wh, during the deposition process for forming the yttria film. The hollow anode current Ih is correlated (proportional) to the amount of electrons flowing into the hollow anode 46, in other words, correlated (proportional) to the amount of ions in the hollow anode plasma 200.

[0093] 13, for example, in the case of the conventional technology (thick long dashed line with triangle mark), the hollow anode current Ih is stable for a while from the start of the film formation process, but after about 15 minutes from the start of the film formation process, the hollow anode current Ih begins to decrease, that is, the amount of ions in the hollow anode plasma 200 begins to decrease. Then, after about 25 minutes from the start of the film formation process, the hollow anode current Ih settles down somewhat, but its value is about 2 / 3 of what it was at the start of the film formation process. Thus, in the conventional technology, the hollow anode current Ih is unstable, that is, the amount of ions in the hollow anode plasma 200 fluctuates, in other words, the hollow anode plasma 200 is unstable.

[0094] Focusing on the reference technology (thick short dashed line with square mark), the hollow anode current Ih is considerably smaller than, for example, the hollow anode current Ih in the conventional technology. As mentioned above, this is because, in the reference technology, the hollow anode 46 does not function as an anode in the first place. Nevertheless, the hollow anode current Ih in the reference technology shows a certain value, which is presumably due to some flow of electrons in the main plasma 100 into the hollow anode 46.

[0095] In contrast, in the present embodiment (bold solid line with circles), the hollow anode current Ih is stable, and is much larger than the hollow anode current Ih in the prior art. This is presumably because the hollow anode filament 48 functions as a stable anode, causing a large amount of electrons in the main plasma 100 to flow into the hollow anode filament 48. This shows that in the present embodiment, the amount of ions in the hollow anode plasma 200 is extremely large, that is, the concentration of the hollow anode plasma 200 is extremely high. This is presumably why the present embodiment can stably form a dense, hard, or in other words, high-quality insulating coating.

[0096] As described above, according to this embodiment, an insulating film such as an yttria film can be formed stably with high quality. In particular, since an yttria film has high plasma resistance, this embodiment is extremely useful in fields that require high plasma resistance, such as semiconductor etching devices. Naturally, according to this embodiment, not only insulating films but also conductive films can be formed stably with high quality.

[0097] The present embodiment is a specific example of the present invention, and does not limit the technical scope of the present invention. The present invention can be applied to aspects other than the present embodiment.

[0098] For example, in this embodiment, the case where an yttria film is formed as an insulating film has been described in detail, but the present invention can also be applied to the case where an insulating film other than the yttria film is formed. As an example, a silicon nitride (Si3N4) film was formed and an experiment was carried out to confirm its properties. The film formation conditions in the experiment for the silicon nitride film are shown in FIG. 14.

[0099] As shown in FIG. 14, in the experiment on the silicon nitride film, the flow rate Q [N2] of nitrogen (N2) gas as a reactive gas introduced into the vacuum chamber 12 was set to 80 mL / min. In addition, the pressure P in the vacuum chamber 12 was set to 0.08 Pa, and strictly speaking, the output Wg of the electron gun 22 was controlled so that the pressure P in the vacuum chamber 12 was constant at 0.08 Pa. By this control, the output Wg of the electron gun 22 fluctuated in the range of 3.69 kW to 3.78 kW, and more specifically, the emission current Ig fluctuated in the range of 410 mA to 420 mA with the acceleration voltage Vg of the electron gun 22 constant at 9 kV. Furthermore, the hot cathode heating power Wf was controlled so that the ionization power Wd was constant at 1.2 kW, and more specifically, the ionization current Id was constant at 30 A with the ionization voltage Vd constant at 40 V. The hollow anode voltage Vh was set to 40 V. The substrate bias voltage Vb (average value) was set to −600 V. The frequency of the substrate bias voltage Vb was 100 kHz, and the duty ratio was 20%. The film formation time was set to 40 min.

[0100] The substrate stand 30 in the silicon nitride film experiment was the same as that in the yttria film experiment, that is, a disk stand with a diameter of 360 mm and a thickness of 3 mm. The distance between the opening of the crucible 20 and the surface of the substrate 28 to be processed was also 450 mm, the same as in the yttria film experiment. However, the diameter of the opening of the crucible 20 was 80 mm, and a carbon hearth liner with a weight of 70 g was set in the crucible 20, and about 110 g of silicon was filled into the hearth liner.

[0101] In the experiment on this silicon nitride film, although illustration is omitted, the result was obtained that the silicon nitride film can be stably formed. Specifically, a high-hardness silicon nitride film was formed, with a film thickness of 1.3 μm and a Knoop hardness of 2700 HK when the indenter load was 25 g. In addition, the silicon nitride film formed in this experiment was transparent, and its refractive index was 2.08. This confirmed that a high-quality silicon nitride film was formed.

[0102] Incidentally, in the experiment on this silicon nitride film, the substrate bias current Ib during the film formation process for forming the silicon nitride film was stable at about 1 A. The hollow anode current Ih was also stable at about 30 A.

[0103] In addition, although detailed explanation including drawings will be omitted, it was confirmed that a gadolinium oxide (Gd3O2) film can also be formed stably with high quality. Thus, according to the present invention, various insulating films can be formed stably with high quality.

[0104] Furthermore, the hollow anode filament 48 is a member formed by forming a tungsten filament with a diameter (wire diameter) ds of 1 mm into a spiral shape, but is not limited thereto. For example, the diameter ds of the hollow anode filament 48 may be smaller than 1 mm. The smaller the diameter ds of the hollow anode filament 48, the easier it is to heat the hollow anode filament 48, which is favorable in that respect. However, the smaller the diameter ds of the hollow anode filament 48, the lower the mechanical strength of the hollow anode filament 48, which is unfavorable in that respect. In particular, the hollow anode filament 48 is periodically subjected to a blasting treatment, and the blasting treatment is performed while the hollow anode filament 48 is attached to the tip 46a of the hollow anode 46, so it is required to have a certain level of mechanical strength or more. For this reason, the diameter ds of the hollow anode filament 48 needs to be a certain level or more, but if the diameter ds is excessively large, the heat capacity of the hollow anode filament 48 itself becomes large, making it difficult to heat. For these reasons, it is essential that the diameter ds of the hollow anode filament 48 be set to 0.5 mm or more and 2.0 mm or less.

[0105] In addition, the tip 46a of the hollow anode 46 may have a configuration as shown in FIG. 15. The tip 46a shown in FIG. 15 has a step 464 on the outer periphery of the gas outlet side of the tip 46a by reducing the diameter (outer diameter) Df of the tip 46a on the gas outlet side. When the tip 46a shown in FIG. 15 is used, the hollow anode filament 48 is used whose spiral diameter Ds is slightly smaller in accordance with the diameter Df of the tip 46a on the gas outlet side. According to this configuration, the step 464 functions as a stopper to prevent the hollow anode filament 48 from slipping down. Alternatively, the hollow anode filament 48 may be simply attached to the hollow anode 46 by being placed on the step 464.

[0106] In addition, when the tip portion 46a shown in FIG. 15 is employed, the hollow anode filament 48 may have a configuration as shown in FIG. 16. The hollow anode filament 48 shown in FIG. 16 has an extremely short (flat) cylindrical base portion 480 and a plurality of straight rod-shaped electron inlet portions 482, 482, ... connected to the base portion 480. Each electron inlet portion 482 is provided so as to extend from one end of the base portion 480 along the central axis direction of the base portion 480. The hollow anode filament 48 shown in FIG. 16 is attached to the tip portion 46a by placing the base portion 480 on the step 464 of the tip portion 46a with each electron inlet portion 482 facing in the same direction as the gas outlet of the tip portion 46a shown in FIG. 15. 16, like the previously described spiral hollow anode filament 48, has a small heat capacity and a shape that makes it easy to capture electrons accelerated from the main plasma 100, and therefore provides the same effects as the spiral hollow anode filament 48. Of course, a hollow anode filament 48 having a configuration different from that shown in FIG. 16 may be used.

[0107] The present invention is not limited to application to the reactive ion plating apparatus 10, but can also be applied to a reactive ion plating method. [Explanation of symbols]

[0108] 10...Ion plating equipment 12...Vacuum chamber 18... Evaporation source 20...crucible 22...Electron gun 24... Evaporation material 28... Substrate 32 ... Substrate bias power supply 34 ... Hot cathode filament 36…Hot cathode heating power supply device 38...Ionization power supply 40...Current detector 42 ... Heating controller 46…Hollow anode 46a...Tip 48 ... Hollow anode filament 50…Power supply device for hollow anode 52 ... Pressure gauge 54 ... Evaporation rate controller

Claims

1. A reactive ion plating apparatus for forming a reaction film, which is a compound of particles of an evaporation material and particles of a reactive gas, on a surface of a workpiece, the reaction film comprising the particles of the evaporation material and the particles of the reactive gas ... a vacuum chamber in which the workpiece is placed and the inside of which is evacuated; a container means for containing the evaporation material, the container means being provided below the object to be treated inside the vacuum chamber; an evaporation means for evaporating the evaporation material contained in the containing means; a hot cathode that is disposed between the container and the object to be treated and emits thermoelectrons; a first ionization power supply means for supplying a first ionization power of a direct current to the containing means and the hot cathode, the first ionization power being used to ionize particles of the evaporation material evaporated by the evaporation means, with the containing means serving as an anode and the hot cathode serving as a cathode; a thermoelectron emission amount control means for controlling an amount of the thermoelectrons emitted by the hot cathode so that a current component of the first ionization power is constant; a hollow anode having a hollow portion through which the reactive gas flows and through which the reactive gas is introduced into the vacuum chamber; a second ionization power supply means for supplying a second ionization power of a direct current to the hollow anode and the containing means, the second ionization power being used to ionize particles of the reactive gas introduced into the vacuum chamber, with the hollow anode as an anode and the containing means as a cathode; a heater that is electrically connected to the hollow anode and is provided at an outlet of the hollow anode for discharging the reactive gas into the vacuum chamber, the heater being heated to a temperature equal to or higher than the evaporation temperature of the particles of the evaporation material by Joule heat generated by receiving an inflow of electrons in the plasma induced by the supply of the first ionizing power; and A reactive ion plating apparatus comprising a bias power supply means for supplying a bias power to the workpiece to accelerate the ionized particles of the evaporation material and the ionized particles of the reactive gas toward a surface of the workpiece.

2. 2. The reactive ion plating apparatus according to claim 1, wherein the heating body is a spiral body that surrounds the periphery of the discharge port and extends in a spiral shape in the discharge direction of the reactive gas from the discharge port.

3. 2. The reactive ion plating apparatus according to claim 1, wherein the heater is detachable from the discharge port.

4. 4. The reactive ion plating apparatus according to claim 3, wherein the heater can be attached to the discharge port without using a member for attaching the heater to the discharge port.

5. 2. The reactive ion plating apparatus of claim 1, wherein the voltage component of the second ionizing power is greater than or equal to 10V and less than or equal to 60V.

6. 2. The reactive ion plating apparatus according to claim 1, further comprising an evaporation rate control means for controlling an evaporation rate of the evaporation material by the evaporation means so that the pressure inside the vacuum chamber is constant while the amount of the reactive gas introduced into the vacuum chamber per unit time is constant.

7. 1. A reactive ion plating method for forming a reaction film, which is a compound of particles of an evaporation material and particles of a reactive gas, on a surface of a workpiece, the reaction film comprising the particles of the evaporation material and the particles of the reactive gas, the method comprising the steps of: The object to be treated is placed inside a vacuum chamber, the inside of which is evacuated, and the evaporation material contained in a container provided below the object to be treated is evaporated. an evaporation step for a thermionic emission step of emitting thermoelectrons from a hot cathode provided between the container and the workpiece; a first ionization power supply step of supplying a first ionization power of a direct current to the containing means and the hot cathode, the first ionization power being used to ionize particles of the evaporation material evaporated in the evaporation step, with the containing means serving as an anode and the hot cathode serving as a cathode; a thermoelectron emission amount control step of controlling an amount of the thermoelectrons emitted by the hot cathode so that a current component of the first ionization power is constant; a reactive gas introducing step of introducing the reactive gas into the vacuum chamber through a hollow portion of a hollow anode having a hollow portion through which the reactive gas flows; a second ionization power supply step of supplying a second ionization power of DC to the hollow anode and the containing means, with the hollow anode as an anode and the containing means as a cathode, for ionizing particles of the reactive gas introduced into the inside of the vacuum chamber; a heater heating step of causing electrons in the plasma induced by the supply of the first ionizing power to flow into a heater provided at an outlet of the hollow anode for discharging the reactive gas into the vacuum chamber while being electrically connected to the hollow anode, and heating the heater to a temperature equal to or higher than the evaporation temperature of the particles of the evaporation material by Joule heat caused by the electrons flowing in; and A reactive ion plating method including a bias power supply step of supplying bias power to a workpiece to accelerate ionized particles of the evaporation material and ionized particles of the reactive gas toward a surface of the workpiece.

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