Ion plating apparatus and method

Abstract

To keep a film deposition rate constant without providing any dedicated means for monitoring the film deposition rate like a film thickness monitor, and thereby to form a single-element film with excellent reproducibility.SOLUTION: In an ion plating device 10 according to the present invention, a vaporized material 24 in a crucible 20 is heated with an electron gun 22 to be vaporized. Then electric power Wf for filament heating is supplied to a filament 34, and ionizing electric power Wd is supplied to the crucible 20 as an anode and the filament 34 as a cathode. A heating temperature of the filament 34 is so controlled that an ionizing current Wd has a constant current component Id. Further, substrate bias electric power Wb is supplied to a substrate 28. Consequently, a single-element film is formed on a treated surface of the substrate 28. In addition, output Wg of the electron gun 22 is so controlled that ionizing current density Js based upon an ion detection current Is from a Faraday cup 52 becomes constant.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ion plating apparatus and method, and more particularly to an ion plating apparatus and method for ionizing particles of an evaporation material and forming a coating containing the ionized particles on the surface of a workpiece. [Background technology]

[0002] An example of a technique related to this type of ion plating apparatus and method, particularly an example of a technique specialized in a reactive ion plating apparatus and method, is disclosed in Patent Document 1. According to the technique disclosed in Patent Document 1, in a vacuum chamber in which a workpiece is placed, an evaporation material contained in a container is evaporated by an evaporation means. The particles of the evaporation material are ionized by supplying a first ionization power of direct current to a pair of electrodes, the container being the anode and a hot cathode provided between the container and the workpiece being the cathode. In addition, a reactive gas is introduced into the vacuum chamber through a hollow anode having a hollow portion. The particles of the reactive gas are ionized by supplying a second ionization power of direct current to a pair of electrodes, the hollow anode being the anode and the container being the cathode. 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. As a result, 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.

[0003] According to the technology disclosed in Patent Document 1, the evaporation rate of the evaporation material by the evaporation means is controlled so that the pressure in the vacuum chamber is constant with the flow rate of the reactive gas constant from the viewpoint of stoichiometry, thereby maintaining the formation rate (film formation rate) of the reaction film constant. This contributes greatly to forming the reaction film as the target with good reproducibility (constant quality). In other words, even if a dedicated means for monitoring the film formation rate such as a film thickness monitor is not provided, the film formation rate is maintained constant, and the reaction film as the target is formed with good reproducibility. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6788081 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the technology disclosed in Patent Document 1 is a technology specialized for a reactive ion plating apparatus and method, that is, a technology specialized for the case where a reactive film is formed as an object. Therefore, the technology disclosed in Patent Document 1 cannot be used for the case where a single element film is formed as an object instead of a reactive film, in other words, a film formation process is performed without introducing a reactive gas into a vacuum chamber.

[0006] Therefore, an object of the present invention is to provide a novel ion plating apparatus and method which, when forming a single-element film as the target object, can maintain a constant film formation rate without the need for a dedicated means for monitoring the film formation rate, such as a film thickness monitor, and thus can form the single-element film with good reproducibility. [Means for solving the problem]

[0007] To achieve this object, the present invention includes a first invention relating to an ion plating apparatus and a second invention relating to an ion plating method.

[0008] The first invention is a method for ionizing particles of an evaporation material consisting of a single element, and using the ionized particles as a component. Single element The ion plating device forms a film on the surface of a workpiece, and includes a vacuum chamber. The workpiece is placed inside the vacuum chamber. The inside of the vacuum chamber is also evacuated. The first invention further includes a container means, an evaporation means, a hot cathode, a first ionization power supply means, a thermoelectron emission amount control means, a bias power supply means, an ion current density detection means, and an evaporation rate control means. The container means is provided below the workpiece inside the vacuum chamber, and 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 workpiece inside the vacuum chamber, 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 ionizes particles of the evaporation material evaporated by the evaporation means. to induce arc discharge The first ionization power is a direct current power for accelerating the ionized particles toward the surface of the workpiece. The thermionic emission amount control means controls the amount of thermionic electrons emitted from the hot cathode so that the current component of the first ionization power is constant. The bias power supply means supplies a bias power to the workpiece for accelerating the ionized particles toward the surface of the workpiece. The ion current density detection means detects an ion current density corresponding to the amount of ionized particles incident on the surface of the workpiece per unit time and per unit area. Then, the evaporation rate control means controls the evaporation rate of the evaporation material by the evaporation means so that the ion current density detected by the ion current density detection means is constant. Here, the film formation process for forming a single element film on the surface of the workpiece is carried out in a state where no gas is introduced into the vacuum chamber. This means: Single element Research, including experiments, has now revealed that the rate of film formation becomes constant (stabilized).

[0009] The ion current density detection means includes, for example, a Faraday cup.

[0010] In this case, it is desirable that the Faraday cup be provided at an appropriate position between the containing means and the object to be treated.

[0011] Additionally, it is desirable that the Faraday cup is disposed so as not to overlap the object to be treated when viewed from the side of the container means.

[0013] The first invention is suitable for forming a conductive or semiconductive coating as an object.

[0014] The second aspect of the present invention is a method for ionizing particles of an evaporation material consisting of a single element, and using the ionized particles as components. Single element The ion plating method for forming a film on the surface of a workpiece includes an evaporation step. In this evaporation step, an 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 the vacuum chamber is evacuated. Furthermore, the second invention includes a thermionic emission step, a first ionizing power supply step, a thermionic emission amount control step, a bias power supply step, an ion current density detection step, and an evaporation rate control step. In the thermionic emission step, thermionic electrons are emitted from a hot cathode provided between the container means and the workpiece inside the vacuum chamber. In the first ionizing power supply step, a first ionizing power is supplied to a pair of electrodes, with the container means as the anode and the hot cathode as the cathode. This first ionizing power ionizes particles of the evaporation material evaporated in the evaporation step. to induce arc dischargeThe thermionic emission amount control step controls the amount of thermoelectrons emitted from the hot cathode so that the current component of the first ionization power is constant. The bias power supply step supplies the workpiece with bias power for accelerating the ionized particles toward the surface of the workpiece. The ion current density detection step detects an ion current density corresponding to the amount of ionized particles incident on the surface of the workpiece per unit time and per unit area. Then, the evaporation rate control step controls the evaporation rate of the evaporation material in the evaporation step so that the ion current density detected in the ion current density detection step is constant. In the ion current density detection step, the ion current density is detected using a Faraday cup. Moreover, the film formation process for forming a single element film on the surface of the workpiece is carried out in a state in which no gas is introduced into the vacuum chamber. Effect of the Invention

[0015] According to the present invention, when a single-element film is to be formed as the target object, the film formation rate can be maintained constant without providing a dedicated means for monitoring the film formation rate, such as a film thickness monitor, and thus the single-element film can be formed with good reproducibility. [Brief description of the drawings]

[0016] [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 diagram showing the configuration of a Faraday cup in one embodiment of the present invention. [Diagram 3] FIG. 3 is a photograph showing the appearance of a Faraday cup in one embodiment of the present invention and the Faraday cup in an attached state. [Figure 4] FIG. 4 is a diagram showing the relationship between the electron gun emission current and the ion current density when the evaporation material is silicon in one embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram showing the relationship between the ion current density and the evaporation rate of silicon and the deposition rate of a silicon film as a target when the evaporation material is silicon in one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing the experimental results in one embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing another experimental result in an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] An embodiment of the present invention will be described with reference to FIGS.

[0018] As shown in FIG. 1, the ion plating apparatus 10 according to this embodiment includes a generally cylindrical vacuum chamber 12. 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 is grounded, that is, the vacuum chamber 12 itself is electrically at 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 with an upward convex shape in order to improve its mechanical strength.

[0019] 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.

[0020] 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 crucible 20 having a roughly cup shape (more specifically, roughly cylindrical with an open top) as an example of 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 target coating. Although not shown in detail, a hearth liner having a shape and dimensions that match 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, carbon (C), which is one of high heat-resistant members, but is not limited to this, and may be made of a high-melting point metal such as tantalum (Ta), molybdenum (Mo), or tungsten (W). Furthermore, the center (axis) of the crucible 20 in the horizontal direction approximately coincides with the center (axis) of the vacuum chamber 12 in the horizontal direction, that is, the evaporation source 18 is disposed so that this coincides.

[0021] 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 the 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 generates an electron beam 22a. The 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 for preventing the crucible 20 from overheating. The housing of the evaporation source 18, including the crucible 20, is grounded.

[0022] 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, or more precisely, the surface to be treated on which a coating is to be formed, facing the evaporation source 18, particularly facing the opening of the crucible 20. The distance between the evaporation source 18 and the substrate 28 (in the up-down direction (vertical direction)), or more precisely, the distance between (the upper edge of) the opening of the crucible 20 and the surface to be treated 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 treated of the substrate 28.

[0023] The substrate stand 30 is connected to a substrate bias power supply device 32, which is an example of 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 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 equivalent value) of the substrate bias voltage Vb is adjusted by this 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. Furthermore, the frequency of the substrate bias power Wb can also be arbitrarily changed within a range of, for example, 50kH to 250kH. In addition, the duty ratio of the substrate bias power Wb (the ratio of the period during which the substrate bias voltage Vb is at a high level voltage in one period of the substrate bias voltage Vb) can also be changed arbitrarily. Here, the frequency of the substrate bias power Wb is set to, for example, 100 kHz. And, the duty ratio of the substrate bias power Wb is set to, for example, 20%.

[0024] Furthermore, a filament 34 as an example of a hot cathode is provided between the evaporation source 18 and the substrate table 30 and close to the evaporation source 18, in other words, slightly above the opening of the crucible 20. The 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 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 filament 34 formed in a spiral shape is, for example, 12 mm, and the number of turns is, for example, 10 (turns). The length of the spirally formed portion of the filament 34 is, for example, 100 mm.

[0025] Here, for example, if the distance (in the vertical direction) between the opening of the crucible 20 and (the spiral center of) the filament 34 is too short, the 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 distance is too long, the density of the evaporated particles of the evaporation material 24 around the 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 distance is appropriately about 10 mm to 100 mm, as described above, and preferably 40 mm to 70 mm, for example 60 mm. The 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.

[0026] Both ends of the filament 34 are connected to a filament heating power supply device 36 as a hot cathode heating power supply means outside the vacuum chamber 12. The filament heating power supply device 36 supplies AC filament heating power Wf as hot cathode heating power to the filament 34. Upon receiving the supply of the filament heating power Wf, the filament 34 is heated and emits thermoelectrons. The capacity of the filament heating power supply device 36 is, for example, 2.4 kW (=40 V × 60 A) at maximum. The filament heating power Wf may be DC power instead of AC power. In any case, the filament heating power supply device 36 only needs to be able to heat the filament 34 to a temperature sufficient to emit thermoelectrons from the filament 34, for example, to about 2000 ° C. to 2500 ° C. The filament 34 is not limited to being made of tungsten, and may be made of a high melting point metal other than tungsten, such as molybdenum or tantalum.

[0027] In addition, one end of the filament 34 is connected to an ionization power supply device 38 serving as a first ionization power supply means outside the vacuum chamber 12. The ionization power supply device 38 supplies an ionization power Wd as a first ionization power to the filament 34. The ionization power Wd is a DC power with a negative potential based on the ground potential. In other words, the ionization power supply device 38 supplies a DC ionization power Wd to a pair of electrodes, the grounded evaporation source 18 serving as an anode and the filament 34 serving as a cathode. The capacity of the ionization power supply device 38 is, for example, a maximum of 9 kW (=60 V×150 A).

[0028] An ionization current detector 40 serving as an ionization current detection means is provided between the ionization power supply 38 and ground. The ionization current detector 40 detects a current component of the ionization power Wd, that is, an ionization current Id. The detection result of the ionization current Id by the ionization current detector 40 is provided to a heating controller 42 serving as an example of a thermionic emission amount control means.

[0029] The heating controller 42 controls the filament heating power supply device 36 so that the ionization current Id detected by the ionization current detector 40 becomes constant, that is, controls the heating temperature of the filament 34, in other words, controls the amount of thermoelectrons emitted from the filament 34. That is, the amount of thermoelectrons emitted from the filament 34 is controlled so that the ionization current Id becomes constant.

[0030] Turning attention to the inside of the vacuum chamber 12 again, within the vacuum chamber 12, the terminal portions at both ends of the filament 34 (portions extending from both ends of the filament 34 to the wall of the vacuum chamber 12) are covered with an appropriate protective cover 44. This cover 44 is made of molybdenum, for example. Furthermore, the cover 44 is electrically insulated from other elements such as the vacuum chamber 12, and is in a so-called electrically floating state.

[0031] 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 functioning as the gas introduction tube, is appropriately 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 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.

[0032] The gas discharge port (one end) of the hollow anode 46 is provided at a predetermined position near the opening of the crucible 20, and more precisely, it is provided 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 discharge port 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 the evaporated particles of the evaporation material 24 described later. This is to prevent a reaction film described later from adhering (accumulating) to (the inside of) the gas discharge port of the hollow anode 46, causing the gas discharge port to narrow. Specifically, the gas discharge port of the hollow anode 46 is provided so as to face upward. The gas discharge port of the hollow anode 46 is provided at approximately the same position as the opening of the crucible 20 in the vertical direction, or at a position slightly above the opening of the crucible 20. In other words, the gas discharge port 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 discharge port 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. The distance between the gas discharge port of the hollow anode 46 and the opening of the crucible 20 in the horizontal direction, more specifically the distance between their centers (axes), depends on various conditions such as the shape and dimensions of the evaporation source 18 including the crucible 20, but is for example 140 mm.

[0033] The gas supply inlet (the other end) of the hollow anode 46 is connected to 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 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.

[0034] The hollow anode 46 is made of a high melting point metal, for example, tantalum. Outside the vacuum chamber 12, the hollow anode 46 is connected to a hollow anode power supply device 48, which is an example of a second ionization power supply means. The hollow anode power supply device 48 supplies a DC hollow anode power Wh as a second ionization power to the hollow anode 46. The hollow anode power Wh is a positive potential power with respect to the ground potential. In other words, the hollow anode power supply device 48 supplies a 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 48 is, for example, a maximum of 2.5 kW (=50 V×50 A).

[0035] In addition, a pressure gauge 50 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 section (measurement section) 50a of the pressure gauge 50 is provided. The main body of the pressure gauge 50 is provided outside the vacuum chamber 12. For example, a Penning vacuum gauge is used as the pressure gauge 50, but the present invention is not limited to this, and a gauge section other than the Penning vacuum gauge, such as an ionization vacuum gauge, may be used. In addition, in FIG. 1, the gauge section 50a of the pressure gauge 50 is provided near the substrate stand 30, but in reality, the gauge section 50a 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.

[0036] Furthermore, a Faraday cup 52 serving as an ion trapping means is provided at an appropriate position within the vacuum chamber 12, more specifically, at an appropriate position between the crucible 20 and the substrate 28. This Faraday cup 52 has a main body 502, as shown in FIG.

[0037] The main body 502 includes a substantially cylindrical ion collector 504, a substantially cylindrical ion collector holder 506 having the same diameter (outer diameter) as the ion collector 504, and a substantially round bar-shaped power supply shaft 508. The ion collector 504 is fixed to the ion collector holder 506 by one M3 hexagonal socket bolt (cap bolt) 510 with its central axis aligned with the central axis of the ion collector holder 506. For this purpose, a bolt insertion hole 504a and a countersunk hole 504b are provided in the ion collector 504. Additionally, a screw hole 506a is provided in the ion collector holder 506. The power supply shaft 508 is provided on the opposite side of the ion collector holder 506 from the ion collector 504 side (the lower side in FIG. 2) with its central axis aligned with the central axis of the ion collector holder 506. The power supply shaft 508 is formed integrally with the ion collector holding unit 506, for example, by machining. In addition, a male screw is formed on a portion of the power supply shaft 508 from the tip side (the lower side in FIG. 2) to the middle, so to speak, a threaded portion is provided. The diameter of the power supply shaft 508 is, for example, 5 mm, and therefore the threaded portion of the power supply shaft 508 is M5 size. Alternatively, a male screw may be formed over the entire power supply shaft 508. Furthermore, the power supply shaft 508 may be a separate member from the ion collector holding unit 506, and may be fixed to the ion collector holding unit 506 by an appropriate means such as welding.

[0038] The main body 502 is held by a main body holder 516 via an appropriate number of, for example, two, insulators 512 and 514 of an appropriate shape and size. The main body holder 516 is roughly cylindrical, with its central axis coinciding with the central axis of the main body 502, and is provided so as to surround the main body 502 except for a part of the power feed shaft 508 (the lower side in FIG. 2). Each of the insulators 512 and 514 is provided between the main body 502 and the main body holder 516 so that the main body 502 and the main body holder 516 are electrically insulated from each other. Then, a nut 518 is screwed onto the threaded portion of the power supply shaft 508, and more specifically, the insulators 512 and 514 and the main body holding portion 516 are sandwiched between the ion collector holding portion 506 and the nut 518, thereby forming an integrated internal unit 520 including the main body 502, the insulators 512 and 514, and the main body holding portion 516. Although not shown in the drawings, before the nut 518 is screwed onto the threaded portion of the power supply shaft 508, a flat washer and a spring washer are attached to the threaded portion of the power supply shaft 508 in this order.

[0039] Furthermore, the internal unit 520 is accommodated in a generally cylindrical housing 522. The housing 522 includes a base 524 and a cover 526. The base 524 accommodates a part of the internal unit 520, specifically, a part on the power supply shaft 508 side (lower side in FIG. 2), with its central axis coinciding with the central axis of the internal unit 520. The internal unit 520 accommodated in the base 524 is fixed to the base 524 by one or more, for example, two, M3 size hexagon socket head bolts 528 and 528. For this purpose, two bolt insertion holes 524a and 524a are provided in the side wall of the base 524. In addition, two screw holes 520a and 520a are provided in the internal unit 520, more precisely, in the side wall of the main body holding part 516. Although not shown, when each hexagon socket bolt 528 is screwed into the screw hole 520a through the bolt insertion hole 524a, a spring washer and a flat washer are first attached to the hexagon socket bolt 528 in this order.

[0040] On the other hand, the lid 526 accommodates the ion collector 504 side (upper side in FIG. 2) part of the internal unit 520 with its central axis aligned with the central axis of the internal unit 520. The lid 526 is fixed to the main body holder 516 by one or more, for example, two, M3 size hexagon socket head bolts 530 and 530. For this purpose, the lid 526 is provided with two bolt insertion holes 526a and 526a, and two countersunk holes 526b and 526b. In addition, the main body holder 516 is provided with two screw holes 516a and 516a. In addition, the lid 526 is provided with a circular through hole 526c centered on its central axis. The through hole 526c functions as an aperture.

[0041] Further, an insertion hole 524b for inserting a power supply line 54 described later is provided at an appropriate position of the base 524, for example, at a position where the central axis passes through. Although detailed illustration is omitted, an appropriate terminal is coupled to one end of the power supply line 54, and this terminal is sandwiched between the nut 518 and another nut 532 screwed into the threaded portion of the power supply shaft 508 in addition to the nut 518, thereby connecting to the power supply shaft 508. The other end of the power supply line 54 is drawn out to the outside of the base 524 (Faraday cup 52) through the insertion hole 524b, and is then connected to the ion detection power supply device 60 described later. Note that even when the nut 532 is screwed into the threaded portion of the power supply shaft 508, a flat washer and a spring washer are attached to the threaded portion of the power supply shaft 508 in this order prior to the nut 532 being screwed into the threaded portion of the power supply shaft 508.

[0042] The outer diameter Da of the Faraday cup 52 is, for example, 42 mm. The dimension along the central axis of the Faraday cup 52, that is, the length dimension L, is, for example, 57 mm. The diameter Db of the aperture (through hole) 526c is, for example, 11.3 mm. In other words, when the area (opening area) of the aperture 526c is 1 cm 2Diameter Db of aperture 526c is set to 11.3 mm (≈2×(1 cm2 / π)1 / 2) so that: . Furthermore, all of the elements constituting Faraday cup 52, except for insulators 512 and 514, are made of a metal having relatively high mechanical strength and high corrosion resistance and heat resistance, for example, stainless steel such as SUS304. Insulators 512 and 514 are formed of an insulating material having relatively high mechanical strength and high corrosion resistance and heat resistance, for example, alumina (Al2O3).

[0043] FIG. 3(A) is a photograph showing the appearance of the Faraday cup 52, and FIG. 3(B) is a photograph showing the state in which the Faraday cup 52 is attached. As can be seen from these photographs, a suitable fixing member 56 is connected to the base 524 constituting the housing 522 of the Faraday cup 52, strictly speaking. The fixing member 56 is connected to the vacuum chamber 12 via a suitable support member 58. The fixing member 56 is made of stainless steel such as SUS304, and the support member 58 is also made of the same stainless steel. That is, the housing 522 of the Faraday cup 52 is electrically and mechanically connected to the vacuum chamber 12 via the fixing member 56 and the support member 58. Furthermore, as described above, the power supply line 54 is drawn out from the Faraday cup 52, and as shown in FIG. 3(B) in particular, the power supply line 54 is covered with a suitable covering material in the vacuum chamber 12. The covering material used here is an insulating material that is relatively flexible and has high corrosion resistance and high heat resistance, such as glass fiber.

[0044] 1, the Faraday cup 52 is provided with the aperture 526c facing the crucible 20. In the vertical direction, the Faraday cup 52 is provided at a position closer to the substrate 28, preferably at a position closer to the substrate 28. If the Faraday cup 52 is provided at a position closer to the crucible 20, a coating is more likely to adhere to the Faraday cup 52, and the frequency of maintenance of the Faraday cup 52, as described below, increases. For example, when the distance between the opening of the crucible 20 and the surface to be processed of the substrate 28 is 450 mm, the distance between the opening of the crucible 20 and the center of the aperture 526c of the Faraday cup 52 is 260 mm. Furthermore, in the horizontal direction, that is, when Faraday cup 52 is viewed from the crucible 20 side (below), Faraday cup 52 is provided at a position that does not overlap substrate 28 (does not shade substrate 28). Note that in Fig. 1, for convenience of illustration, Faraday cup 52 is drawn at a position that overlaps substrate 28 when viewed from the crucible 20 side, but in reality, it is provided at a position that does not overlap substrate 28.

[0045] As described above, the power supply line 54 is drawn from the Faraday cup 52, and the power supply line 54 drawn from the Faraday cup 52 is connected to the ion detection power supply device 60 as an ion detection power supply means outside the vacuum chamber 12. The ion detection power supply device 60 supplies ion detection power Ws to the Faraday cup 52, more precisely to the main body 502, via the power supply line 54. This ion detection power Ws is a DC power with a negative potential based on the ground potential. In particular, the ion detection voltage Vs, which is a voltage component of the ion detection power Ws, is set to, for example, -150 V based on the ground potential. The capacity of the ion detection power supply device 60 is, for example, a maximum of 150 W (= 300 V × 0.5 A).

[0046] The Faraday cup 52 (main body 502) is supplied with an ion detection power Ws, in other words, an ion detection voltage Vs of -150 V with respect to the ground potential as a reference, and captures ions among the charged particles in the plasma 100 described below. The Faraday cup 52 then outputs an ion detection current Is that corresponds to the amount of captured ions, more specifically, the amount of ions per unit time that are incident on the ion collector 504 (including the head of the hexagon socket bolt 510) via the aperture 526c. As described above, the area of ​​the aperture 526c is 1 cm. 2 Therefore, the ion detection current Is represents an ion current density Js corresponding to the amount of ions incident per unit time and per unit area on the ion collector 504 via the aperture 526c. The ion current density Js is proportional to the amount of ions incident on the processing surface of the substrate 28 per unit time and per unit area, that is, proportional to the ion current density on the processing surface of the substrate 28.

[0047] Furthermore, an ion current density detector 62 is provided between the ion detection power supply 60 and the ground. This ion current density detector 62 constitutes an example of an ion current density detection means in cooperation with the Faraday cup 52 and the ion detection power supply 60. That is, the ion current density detector 62 detects the ion current density Js based on the ion detection current Is, which is also a current component of the ion detection power Ws. As described above, the ion detection current Is represents the ion current density Js itself. The detection result by this ion current density detector 62 is provided to an evaporation rate controller 64, which is an example of an evaporation rate control means.

[0048] The evaporation rate controller 64 controls the output Wg of the electron gun 22 via the electron gun power supply device 26 so that the ion current density Js detected by the ion current density detector 62 becomes constant, that is, controls the evaporation rate of the evaporation material 24. The evaporation rate controller 64 may be incorporated in the electron gun power supply device 26 or the ion current density detector 62.

[0049] In addition, a shutter 66 is provided between the filament 34 and the substrate stand 30 in the vacuum chamber 12, preferably at a position close to the filament 34. The shutter 66 selectively transitions between an open state in which the surface to be processed of the substrate 28 is exposed toward 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 66 is made of a non-magnetic metal, such as stainless steel, for example SUS304, which has a relatively high mechanical strength, high corrosion resistance, and high heat resistance. The shutter 66 is electrically insulated from other components such as the vacuum chamber 12, that is, it is in an electrically floating state. The distance from the shutter 66 (the lower surface) to the opening of the crucible 20 is, for example, about 100 mm. The shutter 66 can also be seen in FIG. 3(B). Also visible in FIG. 3(B) is a filament 34.

[0050] Additionally, 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. This heater may be, for example, a ceramic heater, but is not limited thereto and other types of heaters such as carbon heaters, lamp heaters, and sheath heaters may also be used. This heater receives heater heating power from a heater heating power supply device outside the vacuum chamber 12 to heat the inside of the vacuum chamber 12, and thus heats the substrate 28.

[0051] According to the ion plating apparatus 10 having such a configuration, a single element film can be formed as a target object, and also a reaction film can be formed. For example, when forming a silicon (Si) film, which is one of the single element films, as a target object, the following procedure is followed.

[0052] That is, first, high-purity silicon as the evaporation material 24 is placed in the crucible 20. The silicon as the evaporation material 24 is, for example, a granular body having a diameter of about 2 mm to 5 mm, but is not limited to this. In addition, a substrate 28 is attached to a substrate stand 30. Then, the vacuum chamber 12 is sealed, and the inside of the vacuum chamber 12 is evacuated by the vacuum pump 16 to a pressure of 1×10 -3 The pressure in the vacuum chamber 12 is evacuated to a pressure P of about 1 Pa, and a so-called vacuum drawing is performed. At the same time as this vacuum drawing, a heat treatment is performed by the heater described above to heat the inside of the vacuum chamber 12 including the substrate 28, and the substrate 28 is heated to, for example, about 200° C. During this vacuum drawing and heat treatment, the shutter 66 is kept closed, including for the purpose of protecting the evaporation material 24 in the crucible 20 (from contaminants, etc.).

[0053] 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 66 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 46a 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 -2The filament 34 is heated to a temperature of 1000° C. and the filament 34 is heated to a temperature of 1000° C. ... and the filament 34 is heated to a temperature of 1000° C. and the filament 34 is heated to a temperature of 1000° C. and the filament 34 is heated to a temperature of 1000° C. and the filament 34 is heated to a temperature of 1000° C. and the filament 34 is heated to a temperature of 1000° C. and the filament 34 is heated to a temperature of The plasma 100 is a low-voltage, high-current arc discharge. Note that the introduction of argon gas and hydrogen gas into the vacuum chamber 12 may be started separately (at different times) instead of simultaneously.

[0054] At this time, the ionization voltage Vd, which is the voltage component of the ionization power Wd, is set to an appropriate constant value. At the same time, the filament heating power Wf is controlled so that the ionization current Id, which is the current component of the ionization power Wd, becomes an appropriate constant value, that is, the amount of thermoelectrons emitted by the filament 34 is controlled. Note that the ionization current Id represents the current flowing into the crucible 20 as the anode, and is proportional to the amount of ions (here, argon ions and hydrogen ions) in the plasma 100.

[0055] 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 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 (intensively) ionized in the vicinity of the gas outlet of the hollow anode 46, and thus a hollow anode plasma 200 is induced. Moreover, 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, so that a hollow anode plasma 200 with a very high density is induced. This embodiment of the hollow anode plasma 200 is also a low-voltage, high-current arc discharge.

[0056] Most of the electrons that contribute to the induction of the hollow anode plasma 200 are electrons (plasma electrons) generated as a result of ionization of the argon gas and hydrogen gas particles among the electrons in the plasma 100. In other words, the thermoelectrons emitted from the filament 34 do not contribute to the induction of the hollow anode plasma 200. This is considered to be due to the relatively long distance between the filament 34 and the gas outlet of the hollow anode 46. As evidence of this, it has been confirmed that even when the filament heating power Wf is supplied to the filament 34 and the hollow anode power Wh is supplied to the hollow anode 46, the plasma 100 is not induced and the hollow anode plasma 200 is not induced when the ionization power Wd is not supplied.

[0057] In this manner, while the 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 66 is opened. Then, the argon ions and hydrogen ions in the 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 organic contaminants, oxide films, and the like attached to the surface of the substrate 28 to be processed.

[0058] 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 66 is closed. At the same time, the introduction of argon gas and hydrogen gas into the vacuum chamber 12 is stopped. This causes the plasma 100 and hollow anode plasma 200 to disappear temporarily. After that, a film formation process is performed to form a silicon film on the processing surface of the substrate 28.

[0059] In this film forming process, the pressure P in the vacuum chamber 12 is, for example, 1×10 -4The pressure is maintained at about 100 Pa. Then, 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 filament 34 is supplied with a filament heating power Wf and an ionization power Wd. Therefore, similar to the discharge cleaning process described above, the thermoelectrons emitted from the filament 34 are accelerated toward the crucible 20 as the anode. Then, the accelerated thermoelectrons collide inelastically with the evaporated particles of the evaporation material 24. As a result, the evaporated particles of the evaporation material 24 are ionized, that is, ionized, and silicon ions are generated. Furthermore, the electrons emitted with this ionization flow into the crucible 20 as the anode. As this phenomenon continues, a plasma 100 is induced again by the arc discharge.

[0060] 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 filament 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.

[0061] In this manner, with plasma 100 newly induced, more specifically, with plasma 100 stabilized, shutter 66 is opened. Then, silicon ions in plasma 100 are accelerated toward the processing surface of substrate 28 and are incident on the processing surface of substrate 28. As a result, a silicon film is formed on the processing surface of substrate 28.

[0062] In this film formation process, the output Wg of the electron gun 22 is controlled so that the above-mentioned ion current density Js is constant, that is, the evaporation rate of the evaporation material 24 is controlled. By performing such feedback control, the formation rate of the silicon film, that is, the film formation rate, is stabilized. That is, the film formation rate is stabilized without providing a dedicated means for monitoring the film formation rate, such as a film thickness monitor. This will be described in detail later.

[0063] This film formation process is performed until a silicon film with a desired thickness is formed. After the film formation process is completed, the shutter 66 is closed. Then, the electron gun 22 is de-energized. At the same time, the supply of the substrate bias power Wb to the substrate 28 is stopped. Furthermore, the supply of the filament heating power Wf to the filament 34 is stopped, and the supply of the ionization power Wd to the filament 34 is stopped. This causes the plasma 100 to disappear. 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 taken out of the vacuum chamber 12. This completes a series of surface treatments including the film formation process for forming a silicon film.

[0064] As described above, in the film formation process, the output Wg of the electron gun 22 is controlled so that the ion current density Js is constant, that is, the evaporation rate of the evaporation material 24 is controlled, thereby stabilizing the film formation rate. To verify this, first, an experiment was conducted to confirm the relationship between the output Wg of the electron gun 22, and more precisely, the emission current Ig, which is the current component of the output Wg of the electron gun 22, and the ion current density Js. The results are shown in FIG. 4.

[0065] In this experiment, silicon was used as the evaporation material 24. The pressure P in the vacuum chamber 12 was set to 1×10 -4The vacuum pressure was maintained at 100 V. Furthermore, silicon was evaporated as the evaporation material 24 while appropriately changing the emission current Ig with the acceleration voltage Vg, which is the voltage component of the output Wg of the electron gun 22, held constant at 9 kV. In addition, the filament heating power Wf was controlled so that the ionization current Id was 20 A with the ionization voltage Vd held constant at 30 V. The average value of the substrate bias voltage Vb was set to -100 V (constant). Incidentally, no discharge cleaning gas was introduced into the vacuum chamber 12, anti No reactive gas was introduced into the vacuum chamber 12. In addition, no hollow anode power Wh was supplied.

[0066] 4, the ion current density Js is proportional to the emission current Ig, that is, proportional to the output Wg of the electron gun 22. Here, the output Wg of the electron gun 22 correlates with the evaporation rate of the evaporation material 24, more specifically, is approximately proportional to the evaporation rate of the evaporation material 24, and is therefore approximately proportional to the film formation rate. Therefore, it is considered that the ion current density Js is also approximately proportional to the evaporation rate of the evaporation material 24, and is therefore approximately proportional to the film formation rate.

[0067] Next, an experiment was carried out to confirm the relationship between the ion current density Js and the evaporation rate of silicon as the evaporation material 24 and the deposition rate of the silicon film. The results are shown in FIG.

[0068] In this experiment, the pressure P in the vacuum chamber 12 was set to 1×10 -4 The ionization voltage Vd was kept at 30 V (constant), and the filament heating power Wf was controlled so that the ionization current Id was 20 A. Additionally, the average value of the substrate bias voltage Vb was set to -100 V (constant). The output Wg of the electron gun 22 was controlled so that the ion current density Js was an appropriate value, and the film formation process was carried out for 30 minutes under the conditions where the ion current density Js was set to an individual value. In this experiment, no discharge cleaning gas was introduced into the vacuum chamber 12, antiNo reactive gas was introduced into the vacuum chamber 12. In addition, no hollow anode power Wh was supplied.

[0069] 5, the evaporation rate of the evaporation material 24 is roughly proportional to the ion current density Js, and strictly speaking, the relationship follows a gentle curve, i.e., the relationship is constant. Similarly, the film formation rate is roughly proportional to the ion current density Js, and strictly speaking, the relationship follows a gentle curve, i.e., the relationship is constant.

[0070] From these experimental results, it was verified that the film formation rate can be stabilized by controlling the output Wg of the electron gun 22 so that the ion current density Js is constant, that is, by controlling the evaporation rate of the evaporation material 24. In other words, it was found that the film formation rate can be stabilized by controlling the evaporation rate of the evaporation material 24 using the ion current density Js as an index.

[0071] Here, it is assumed that silicon particles as evaporated particles are ionized by the impact of thermal electrons to become monovalent silicon ions. In this case, for example, 1 mA / cm 2 The ion current density Js is converted into the amount of ions incident (incident frequency) per unit time and unit area, which is 6.25 × 10 15 pieces / (cm 2 ·s). Although detailed explanation is omitted, when the ratio of silicon ions to neutral particles incident on the substrate 28 in this embodiment was examined, the ratio was about 55%. Furthermore, when titanium (Ti) was used as the evaporation material 24, the ratio of titanium ions to neutral particles incident on the substrate 28 was examined, the ratio was about 60%. Thus, according to this embodiment, since the ratio of ions incident on the substrate 28 is relatively (significantly) large, it is considered that the film formation rate can be stabilized by controlling the evaporation rate of the evaporation material 24 using the ion current density Js as an index.

[0072] Furthermore, we conducted an experiment to determine whether practical reproducibility could be obtained when forming a silicon film as the target object. The results are shown in Figure 6.

[0073] In this experiment, two types of substrates 28 were used. Specifically, a rectangular flat silicon wafer having dimensions of 20 mm×20 mm×0.63 mm and mirror-finished on one side was used as substrate 28 for measuring the thickness and internal stress of the silicon film. In addition, a rectangular flat SKH4 (high-speed tool steel) having dimensions of 16 mm×20 mm×5 mm and mirror-finished on one side was used as substrate 28 for measuring the hardness of the silicon film. Then, prior to the film formation process for forming the silicon film, discharge cleaning was performed in the manner described above, and then the film formation process for forming the silicon film was performed. In the film formation process for forming this silicon film, the pressure P in vacuum chamber 12 was set to 1×10 -4 Pa. In addition, the filament heating power Wf was controlled so that the ionization current Id was 20 A with the ionization voltage Vd being 30 V (constant). Furthermore, the average value of the substrate bias voltage Vb was set to -100 V (constant). The ion current density Js was set to 1.75 mA / cm 2 The output Wg of the electron gun 22 was controlled so that the film formation process was performed under these conditions for 30 minutes, and the film formation process for 30 minutes was performed five times (batches).

[0074] According to the experimental results shown in Fig. 6, particularly the graph shown in Fig. 6(A), the variation in the thickness of the silicon film is suppressed to 11.56μm±0.85μm, that is, the variation is suppressed to ±7.4%. Since the variation in the film thickness is generally (industrially) considered to be sufficient for practical use if it is ±10%, it can be seen that according to this embodiment, the reproducibility of the thickness of the silicon film sufficient for practical use can be obtained.

[0075] 6B, the variation in hardness of the silicon film is suppressed to 1005HK±45HK, that is, ±4.5%. Since the variation in hardness is generally considered to be sufficient for practical use if it is ±10% or less, it can be seen that this embodiment can obtain sufficient reproducibility for the hardness of the silicon film for practical use.

[0076] 6(C), the variation in the internal stress of the silicon film is suppressed to -0.445GPa±0.005GPa, that is, the variation is suppressed to ±1.1%. Since the variation in internal stress is generally considered to be sufficient for practical use if it is within ±10%, it can be seen that this embodiment can obtain reproducibility in the internal stress of the silicon film that is sufficient for practical use.

[0077] That is, it was confirmed that, according to this embodiment, when forming a silicon film, reproducibility sufficient for practical use was obtained.

[0078] As described above, according to this embodiment, a reaction film can be formed as the target object. For example, in the case of forming a silicon carbide (SiC) film as the target object, which is one of the reaction films, the following procedure is followed.

[0079] That is, similarly to the case of forming the above-mentioned silicon film as the target object, high-purity silicon is placed in the crucible 20 as the evaporation material 24. In addition, a substrate 28 is attached to a substrate stand 30. Then, the vacuum chamber 12 is sealed, and evacuation and heating processes are performed, followed by discharge cleaning. Then, a film formation process is performed to form a silicon carbide film.

[0080] In this film formation process, acetylene (C2H2) gas as a reactive gas (material gas) is introduced into the vacuum chamber 12. Then, the pressure in the vacuum chamber 12 is increased to, for example, 2×10 -2The pressure is maintained at or below 1 Pa. At the same time, the electron gun 22 of the evaporation source 18 is energized to evaporate the evaporation material 24. At this time, the filament 34 is supplied with the filament heating power Wf and the ionization power Wd. Therefore, similar to the discharge cleaning process described above, the thermoelectrons emitted from the filament 34 are accelerated toward the crucible 20 as the anode. The accelerated thermoelectrons then inelastically collide with the evaporated particles of the evaporation material 24. As a result, the evaporated particles of the evaporation material 24 are ionized, that is, silicon ions are generated. Furthermore, the electrons emitted in association with this ionization flow into the crucible 20 as the anode. In parallel with this, the thermoelectrons accelerated from the filament 34 toward the crucible 20 also inelastically collide with the particles of the acetylene gas. As a result, the particles of the acetylene gas are also ionized, that is, ionized, and acetylene ions are generated. Furthermore, electrons emitted as a result of this ionization also flow into the crucible 20. As this phenomenon continues, a plasma 100 is induced by an arc discharge.

[0081] 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 filament 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.

[0082] In addition, hollow anode power Wh is supplied to the hollow anode 46. This accelerates electrons in the plasma 100 toward the gas outlet of the hollow anode 46. The accelerated electrons inelastically collide with acetylene gas particles discharged from the gas outlet of the hollow anode 46. As a result, the acetylene gas particles are actively ionized even in the vicinity of the gas outlet of the hollow anode 46, and hollow anode plasma 200 is induced by arc discharge.

[0083] In this manner, with plasma 100 and hollow anode plasma 200 induced, more specifically, with plasma 100 and hollow anode plasma 200 stable, shutter 66 is opened. Then, ions in plasma 100 and hollow anode plasma 200 are accelerated toward the processing surface of substrate 28 and are incident on the processing surface of substrate 28. As a result, a silicon carbide film, which is a compound of silicon particles containing silicon ions and acetylene particles containing acetylene ions, is formed on the processing surface of substrate 28.

[0084] In the film forming process for forming the silicon carbide film, the output Wg of the electron gun 22 is controlled so that the ion current density Js is constant, that is, the evaporation rate of the evaporation material 24 is controlled. Carbonization The deposition rate of the silicon film is stabilized.

[0085] The film forming process for forming the silicon carbide film is performed until the silicon carbide film with the desired thickness is formed. After the film forming process is completed, the shutter 66 is closed. Then, the power supply to the electron gun 22 is stopped. At the same time, the introduction of acetylene 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 filament heating power Wf to the filament 34 is stopped, and the supply of the ionization power Wd to the filament 34 is stopped. Then, the supply of the hollow anode power Wh to the hollow anode 46 is stopped. As a result, the plasma 100 and the hollow anode plasma 200 disappear. Then, the vacuum chamber 12 is evacuated again, and after an appropriate cooling period of about 30 minutes is left 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 taken out of the vacuum chamber 12. This completes a series of surface treatments including a film formation process for forming a silicon carbide film.

[0086] An experiment was also carried out to determine whether the silicon carbide film formed in this manner could be reproducibly used for practical purposes. The results are shown in Figure 7.

[0087] In this experiment, the same substrate 28 as that in the experiment according to FIG. 6 was used. In the film forming process for forming the silicon carbide film, the flow rate of the acetylene gas was set to 84 mL / min. In addition, the filament heating power Wf was controlled so that the ionization current Id was 40 A with the ionization voltage Vd set to 30 V (constant). Furthermore, the hollow anode voltage Vh, which is a voltage component of the hollow anode power Wh, was set to 30 V (constant). As a result, as described above, the electrons in the plasma 100 are accelerated toward the gas outlet of the hollow anode 46, specifically, accelerated with an energy of 30 eV. The accelerated electrons inelastically collide with particles of acetylene gas discharged from the gas outlet of the hollow anode 46, and the particles of the acetylene gas are actively ionized. At this time, the current flowing through the hollow anode 46, that is, the hollow anode current Ih, which is a current component of the hollow anode power Wh, was about 30 A. In addition, the average value of the substrate bias voltage Vb was set to −400 V (constant). The ion current density Js was set to 2 mA / cm 2 The output Wg of the electron gun 22 was controlled so as to satisfy the following condition. More specifically, the emission current Ig was controlled while the acceleration voltage Vg was set to 9 kV (constant). The emission current Ig at this time was 430 mA to 460 mA. The pressure P within the vacuum chamber 12 was not actively controlled, but was kept at approximately 2×10 -2 The film formation process under these conditions was carried out for one hour, and the same one-hour film formation process was carried out five times.

[0088] According to the experimental results shown in Fig. 7, particularly according to the graph shown in Fig. 7(A), the variation in the thickness of the silicon carbide film is suppressed to 4.58 µm ± 0.16 µm, that is, ± 3.6%. From this, it is understood that according to this embodiment, the thickness of the silicon carbide film can be reproducibly sufficient for practical use.

[0089] 7B, the variation in hardness of the silicon carbide film is suppressed to 2515HK±166HK, that is, ±6.6%. This shows that the present embodiment can provide sufficient reproducibility for practical use in terms of the hardness of the silicon carbide film.

[0090] 7(C), the variation in the internal stress of the silicon carbide film is suppressed to -1.48GPa±0.04GPa, that is, ±2.7%. This shows that the present embodiment can obtain sufficient reproducibility for practical use for the internal stress of the silicon carbide film.

[0091] That is, it was confirmed that, according to this embodiment, reproducibility sufficient for practical use was obtained also for silicon carbide films.

[0092] As described above, according to this embodiment, the output Wg of the electron gun 22 is controlled so that the ion current density Js is constant, that is, the evaporation rate of the evaporation material 24 is controlled, thereby stabilizing the film formation rate and obtaining good reproducibility. This is the same whether a single element film is formed as the target or a reaction film is formed. That is, according to this embodiment, even if a single element film is formed as the target or a reaction film is formed, and especially even if a single element film is formed, the film formation rate can be maintained constant without providing a dedicated means for monitoring the film formation rate such as a film thickness monitor, and thus obtaining good reproducibility.

[0093] Furthermore, according to this embodiment, in the film forming process, the crucible 20 is used as an anode, the filament 34 is used as a cathode, and an ionization power Wd is supplied to the pair of electrodes, whereby a plasma 100 is induced by arc discharge, that is, an extremely dense plasma 100 is induced. Therefore, the evaporated particles of the evaporation material 24 can be ionized without using a discharge gas such as argon gas.

[0094] Furthermore, according to this embodiment, the filament heating power Wf is controlled so that the ionization current Id is constant during the film formation process. This stabilizes the amount of ions in the plasma 100. This also greatly contributes to obtaining good reproducibility.

[0095] In addition, according to this embodiment, when a reactive film is formed as an object, reactive gas particles are actively ionized by hollow anode plasma 200 induced separately from plasma 100 in the film formation process for forming the reactive film. Therefore, for example, compared to the case where only plasma 100 is induced, reactive gas particles are ionized more efficiently, the amount of ions generated increases, and the reactivity of the reactive gas particles is improved. This contributes greatly to the formation of a high-quality reactive film, and is particularly effective in forming a high-quality reactive film even at a high film formation rate.

[0096] 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.

[0097] For example, in this embodiment, the case where a silicon film and a silicon carbide film are formed as the object has been described in detail, but the present invention can also be applied to the case where other single element films and reaction films are formed as the object. That is, the present invention can be applied to the case where various coatings such as metal films, semiconductor films, oxide films, nitride films, and carbide films are formed as the object, and is particularly suitable for the case where a conductive coating and a semiconductive coating are formed. However, the present invention is not suitable for the case where a highly insulating coating such as an alumina film, a silica (SiO2) film, an yttria (Y2O3) film, an aluminum nitride (AlN) film, or a silicon nitride (Si3N4) film is formed. This is because when a highly insulating coating adheres to the Faraday cup 52, especially to the ion collector 504, a charge-up occurs, which significantly reduces the performance of the Faraday cup 52.

[0098] Furthermore, when only a single-element film is to be formed as the object, the hollow anode 46 and the hollow anode power supply unit 48 do not need to be provided. However, it is necessary to provide a gas inlet pipe for introducing discharge cleaning gas into the vacuum chamber 12, or to use the hollow anode 46 simply as a gas inlet pipe (not functioning as an anode).

[0099] Further, the Faraday cup 52 is not limited to the one shown in FIG. 2, and may have other configurations. Incidentally, the Faraday cup 52 is maintained as appropriate, for example, periodically. That is, when a film forming process is performed, a coating adheres to the Faraday cup 52. In particular, when a coating adheres to the ion collector 504 and the periphery of the aperture 526c of the lid 526 and becomes thick, the coating may peel off, and the ion collector 504 and the lid 526 may short out due to the peeled coating. To avoid this, the Faraday cup 52 is maintained as appropriate, and more specifically, the ion collector 504 and the lid 526 are removed and cleaned (blasted). According to the Faraday cup 52 having the configuration shown in FIG. 2, the ion collector 504 is fixed by one hexagon socket bolt 510, and the lid 526 is fixed by two hexagon socket bolts 530 and 530. Therefore, it is extremely easy to perform maintenance, including removal, cleaning, and installation, of the ion collector 504 and the lid portion 526. This greatly contributes to improving the operability of the ion plating apparatus 10.

[0100] In addition, a plurality of Faraday cups 52 may be provided at appropriate positions, and the ion current density Js may be detected based on the ion detection current Is from the plurality of Faraday cups 52.

[0101] Moreover, the substrate bias power supply device 32 as the bias power supply means is not limited to one that outputs bipolar pulse power as the substrate bias power Wb. As the bias power supply means, it is preferable to adopt an appropriate power supply device, including a DC power supply device and a high frequency power supply device, depending on the type of the substrate 28 and the type of the reactive film. In particular, when the substrate 28 is made of an insulating material, it is preferable to adopt a high frequency power supply device to prevent charge-up.

[0102] The present invention is not limited to application to the ion plating apparatus 10, but can also be applied to an ion plating method. [Explanation of symbols]

[0103] 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 ... Filament 36 ... Filament heating power supply 38... Ionization power supply 40 … Ionization current detector 42 ... Heating controller 46 … Hollow anode 48 … Power supply device for hollow anode 50 ... Pressure gauge 52 ... Faraday cup 60 … Power supply for ion detection 64 … Evaporation rate controller

Claims

1. An ion plating apparatus for ionizing particles of an evaporation material composed of a single element to form a single element film composed of the ionized particles on a surface of a workpiece, comprising: 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 and induce an arc discharge, with the containing means serving as an anode and the hot cathode serving as a cathode; a thermoelectron emission amount control means for controlling the amount of the thermoelectrons emitted from the hot cathode so that the current component of the first ionization power is constant; a bias power supplying means for supplying a bias power to the workpiece so as to accelerate the ionized particles toward the surface of the workpiece; an ion current density detection means for detecting an ion current density corresponding to an amount of the ionized particles incident on the surface of the workpiece per unit time and per unit area; and an evaporation rate control means for controlling an evaporation rate of the evaporation material by the evaporation means so that the ion current density is constant; the ion current density detection means includes a Faraday cup; An ion plating apparatus that performs a film formation process for forming the single element film on the surface of the workpiece without introducing any gas into the vacuum chamber.

2. 2. The ion plating apparatus according to claim 1, wherein the Faraday cup is provided between the container and the object to be treated.

3. 3. The ion plating apparatus according to claim 2, wherein the Faraday cup is disposed so as not to overlap the object to be treated when viewed from the container side.

4. 2. The ion plating apparatus according to claim 1, wherein the single element film is a conductive film or a semiconductive film.

5. 1. An ion plating method for ionizing particles of an evaporation material consisting of a single element to form a single element film containing the ionized particles on a surface of a workpiece, comprising: an evaporation step of evaporating the evaporation material accommodated in a container provided below the object to be treated in a vacuum chamber in which the object to be treated is placed and the inside of the vacuum chamber is evacuated; 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, with the containing means serving as an anode and the hot cathode serving as a cathode, for ionizing the particles of the evaporation material evaporated in the evaporation step and inducing an arc discharge; a thermoelectron emission amount control step of controlling the amount of the thermoelectrons emitted from the hot cathode so that a current component of the first ionization power is constant; a bias power supply step of supplying a bias power to the workpiece for accelerating the ionized particles toward the surface of the workpiece; an ion current density detection step of detecting an ion current density corresponding to an amount of the ionized particles incident on the surface of the workpiece per unit time and per unit area; and an evaporation rate control step of controlling an evaporation rate of the evaporation material in the evaporation step so that the ion current density is constant; An ion plating method in which a film formation process for forming the single element film on the surface of the workpiece is performed in a state in which no gas is introduced into the vacuum chamber.

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