Vacuum arc discharge stabilization structure in film forming apparatus

Abstract

[Problem] The present invention provides a film forming apparatus having a structure with which it is possible to stably generate a vacuum arc discharge. [Solution] Disclosed is a film forming apparatus comprising, in a vacuum chamber, a cathode part 11, an anode part 12, and a magnetic field generator 6 for applying a magnetic field to the anode part. A vacuum arc discharge is generated between the cathode and the anode so as to generate plasma, and the cathode material is evaporated and the plasma is transported along the anode part, so that a film which contains a material substance that constitutes the cathode material is vapor-deposited on the surface of an object to be processed. The anode part has a hollow shape through which plasma can pass, and is provided with an auxiliary anode member 8 which is electrically connected to the anode and projects to the inside of the hollow shape.

Description

Vacuum arc discharge stabilization structure in film deposition equipment

[0001] The present invention relates to a film forming apparatus for depositing a specific substance onto the surface of a workpiece, and in particular to a structure for stabilizing a vacuum arc discharge generated within a vacuum chamber when generating plasma within the vacuum chamber to deposit a film of a specific substance.

[0002] It is generally known that generating plasma can form a thin film on the surface of a workpiece (solid material) or implant ions to improve the surface properties of the workpiece (solid material). Films formed using plasma containing metal and / or nonmetal ions enhance the wear resistance and corrosion resistance of solid surfaces and are useful as protective films. Carbon films formed using carbon plasma are particularly valuable as diamond-like carbon (DLC) films, which are amorphous hybrids of diamond and graphite structures. Metal nitride films, such as titanium nitride films and titanium aluminum nitride films, formed by evaporating metals or alloys such as titanium (Ti) and titanium aluminum (TiAl) in a nitrogen gas atmosphere, are also known to be useful as protective films for tools and parts, as well as for decorative applications. These processes are known as vacuum arc deposition, arc ion plating, arc PVD, cathodic arc deposition, etc. In many common vacuum arc evaporation devices, the vacuum vessel itself functions as the anode, but the present invention relates to a configuration in which the anode is placed inside the vacuum vessel, separate from the vacuum vessel.

[0003] Plasma containing metal and nonmetal ions is generated by vacuum arc discharge. Vacuum arc discharge occurs between a cathode and an anode. Cathode material evaporates from the high-temperature cathode point, which is the origin of the vacuum arc discharge, and the cathode-evaporated material forms vacuum arc plasma. Furthermore, if one or more of reactive gases (nitrogen, oxygen, hydrogen, hydrocarbons, fluorine, silicon, etc.) or inert gases (rare gases) are introduced as atmospheric gases, these gases are also ionized. Surface treatment processes using such plasma have been performed by forming thin films on the surface of workpieces (solid materials) or by ion implantation. Alternatively, a liquid containing the substance to be reacted may be vaporized and introduced into the process chamber.

[0004] In a vacuum arc discharge that forms plasma, constituent particles such as electrons and cathode material evaporation particles (atoms (or molecules)) are emitted from the cathode spot. At the same time, droplets (also called macroparticles) measuring submicrons to hundreds of microns (0.01 to 1000 μm) are also emitted as by-product fine particles. At this time, electrons emitted from the cathode spot collide with the cathode material evaporation particles, ionizing the particles and generating metal ions and / or nonmetal ions. The cathode material evaporation particles are ionized by collision with electrons almost immediately after being emitted from the cathode spot (at a very short distance of approximately several mm from the surface of the cathode). However, some of the cathode material evaporation particles that are not ionized (excluding those that are subsequently ionized), introduced gas particles (molecules or atoms), and reactive particles (molecules) become neutral particles (hereinafter sometimes collectively referred to as neutral particles). These particles are not affected by magnetic fields or electric fields and travel straight in the initial direction of emission. On the other hand, droplets (by-product fine particles) are released by bumping at the cathode, but because they have no charge, they travel in a straight line without being affected by magnetic or electric fields. However, in the surface treatment of the workpiece (solid material), the adhesion of droplets (by-product fine particles) to the substrate surface is a problem. In other words, when droplets (by-product fine particles) adhere to the surface of the workpiece (solid material), the surface becomes uneven, which prevents the uniformity of the thin film from being maintained, resulting in a low-quality or defective product.

[0005] As described above, adhesion of droplets (by-product fine particles) to a workpiece (solid material) is a problem, and various methods for preventing the adhesion of droplets (by-product fine particles) have been investigated. For example, some of the inventors of the present application have proposed a plasma generating device configured to guide a plasma flow emitted from a plasma generating unit (a plasma flow (hereinafter sometimes referred to as a plasma flow) from a vacuum arc plasma generated at a cathode point toward an anode and / or a workpiece) in a desired direction by applying a magnetic field, thereby separating the plasma flow from the droplets (by-product fine particles) (see Patent Document 1).

[0006] Furthermore, in the above configuration, the distance from the plasma generating unit (cathode) to the workpiece is long, which reduces the density (flux) of the evaporated material formed by the arc discharge, limiting the film formation rate. Therefore, in order to improve the film formation rate, the inventors of the present application have devised a configuration in which a magnetic field generating device for guiding the plasma flow is installed in the vacuum chamber to shorten the distance between the plasma generating unit (cathode) and the solid material (workpiece). In this case, a magnetic coil is used as the magnetic field generating device, which is used as an anode (or is configured integrally with the anode). A magnetic field is generated by the self-current flowing through the anode. The application of the magnetic field causes the plasma flow to contract radially (sometimes referred to as "convergence") and guides the direction of the plasma flow, thereby shortening the distance from the cathode to the workpiece (see Patent Document 2).

[0007] JP 2002-008893 A

[0008] In the case of the technology relating to the film forming apparatus disclosed in the aforementioned Patent Document 2, there is a concern that droplets (by-product fine particles) may adhere to a part of the magnetic coil, so a hollow protective member is provided near the magnetic coil so that the plasma flow passes through the hollow interior of the protective member. This protective member is basically configured to be electrically connected to the anode so that it functions as a current collecting member (part of the anode portion) and is configured to allow electrons emitted from the cathode portion to reach it.

[0009] However, in the above-described configuration, when a magnetic field is applied by a magnetic coil (magnetic field generator), the plasma flow radially contracts (converges) as it passes through the hollow interior of the magnetic coil and protective member. However, as the magnetic flux density of the magnetic field applied by the magnetic coil increases, the degree of convergence of the plasma flow increases (further contracting radially), causing the plasma flow to move away from the protective member. Because the protective member is electrically connected to the anode and functions as a current collector, there is a concern that if the protective member (current collector) moves away from the plasma, electrons contained in the plasma cannot reach the protective member (current collector) and therefore cannot receive electrons that carry the arc current. This, in turn, leads to problems such as unstable vacuum arc discharge (high number of arc extinctions per given time).

[0010] The present invention has been made in consideration of the above points, and its object is to provide a film forming apparatus having a structure that can stably generate vacuum arc discharge.

[0011] Therefore, a first configuration of the present invention is a film formation apparatus which includes a cathode, an anode arranged at an appropriate distance from the cathode, and a magnetic field generator which applies a magnetic field to an anode portion which constitutes the anode, within a vacuum chamber, and which generates a vacuum arc discharge between the cathode and the anode to evaporate a cathode material which constitutes the cathode, generates plasma containing the evaporated material, transports the plasma along the anode portion, and vapor-deposits a film containing a raw material which constitutes the cathode material on the surface of a workpiece, characterized in that the anode portion has a hollow shape which allows the plasma to pass through, and includes an anode auxiliary member which is electrically connected to the anode and protrudes into the inside of the hollow shape.

[0012] According to the above configuration, the hollow anode section creates a region through which the plasma flow can pass. Furthermore, by projecting an anode auxiliary member toward the inside of the hollow anode section, the passage of the plasma flow can be obstructed. Vacuum arc discharge involves the emission of constituent particles, such as electrons and cathode material evaporation particles (atoms or molecules), from a cathode point (part of the cathode section). The cathode material evaporation particles collide with electrons immediately after being emitted from the cathode point (very close to the cathode surface, approximately a few millimeters), resulting in ionization and the formation of plasma. To maintain a stable vacuum arc discharge, the arc voltage (the voltage between the cathode and anode) must be kept lower than the power supply output voltage. However, the arc voltage varies depending on the resistance between the plasma flow (positive column) and the anode (positive column resistance) and the cathode point resistance (also known as cathode point depression). In particular, when converging the plasma flow using a magnetic field generator, the positive column resistance increases, resulting in an increase in voltage. Therefore, since the plasma emitted from the cathode point contains some electrons, the anode auxiliary member is positioned in a manner that can obstruct the passage of the plasma flow, allowing the electrons contained in the plasma to reach the anode. Because the anode auxiliary member is electrically connected to the anode, electrons move to the anode, reducing the positive column resistance. As a result, even including the cathode point resistance, the overall resistance between the cathode and anode is reduced, and the voltage between the cathode and anode (arc voltage) also decreases. This makes it possible to suppress the vacuum arc discharge below the power supply output voltage, thereby stabilizing the vacuum arc discharge.

[0013] The second configuration of the present invention is the first configuration, wherein the magnetic field generating device is formed in a substantially cylindrical shape outside the vacuum chamber so as to surround part or all of the anode portion.

[0014] According to the second configuration, the magnetic field generator is formed in a substantially cylindrical shape and is disposed so as to surround the anode, thereby enabling the plasma flow to be guided inside the hollow shape of the anode. Therefore, the anode auxiliary member protruding into the hollow shape of the anode obstructs the passage of the plasma flow while allowing electrons contained in the plasma to reach the anode auxiliary member. Furthermore, in the above configuration, since the magnetic field generator is disposed outside the vacuum chamber, the state of the applied magnetic field can be appropriately adjusted.

[0015] In a third aspect of the present invention, the magnetic field generating device is provided in the vacuum chamber in the first aspect of the present invention, and since the magnetic field generating device can be disposed close to the anode, a magnetic field can be applied in a desired state.

[0016] Therefore, the fourth configuration of the present invention is the third configuration, wherein the magnetic field generating device is constituted by the anode portion or is electrically connected to the anode portion, and a magnetic field is applied to the anode portion by a self-current caused by a vacuum arc discharge generated between the anode and the cathode, and the anode auxiliary member is configured to be electrically connected to either or both of the anode portion and the magnetic field generating device.

[0017] According to the fourth configuration, when a magnetic field generator is provided in the vacuum chamber, it may be an electromagnetic coil, and the electromagnetic coil can generate a magnetic field by utilizing a self-current generated by vacuum arc discharge. In this case, the anode auxiliary member can be electrically connected to the anode, or can be connected to the electromagnetic coil (magnetic field generator) to similarly move electrons.

[0018] In a fifth aspect of the present invention, in any one of the first to fourth aspects, the anode auxiliary member protrudes in at least one location into the hollow shape formed by the anode portion.

[0019] According to the above configuration, a plurality of anode auxiliary members may be provided to increase the area reached by electrons, or if the anode auxiliary member has a structure that significantly obstructs the passage of the plasma flow, only one anode auxiliary member may be provided. The number of locations where the anode auxiliary members should be provided is determined in relation to the state of passage of the plasma flow, taking into consideration the shape, size, protruding direction, etc. of the anode auxiliary member.

[0020] Therefore, the sixth configuration of the present invention is the fifth configuration, wherein the anode auxiliary member has at least one protrusion that protrudes from any position of the anode portion toward the inside of the hollow shape.

[0021] According to the above configuration, by arranging one surface of a protrusion having an appropriate area facing the direction in which the plasma flow passes, it is possible to create a state in which the passage of the plasma flow is obstructed. The "protrusion" is a member that protrudes slightly inside a hollow shape, and basically means a plate-like member that is provided with only its base end fixed and its tip protruding. This plate-like member only needs to have a cross-sectional area that does not become hot even when an arc current is passed through it, and this differs depending on the degree of conductivity. For example, in the case of oxygen-free copper with high conductivity, for an arc current of 30 A, it will have a cross-sectional area of ​​approximately 2 mm. ２ It is preferable that the thickness is 4 mm or more, and more preferably 4 mm or more. ２ That's all. Considering mechanical strength, stainless steel or brass can also be used, but because their conductivity is lower than that of oxygen-free copper, a larger cross-sectional area is required. Thus, various conductive materials can be selected by adjusting the cross-sectional area appropriately depending on the material. Furthermore, the surface shape of the plate-shaped member does not need to be specific, as long as the front and back have appropriate areas. If one surface of this protrusion faces the direction in which the plasma passes, that surface may obstruct the passage of the plasma flow. Furthermore, if the protrusion is positioned at an appropriate angle relative to the direction in which the plasma passes, it is possible to guide the plasma flow in the angled direction while appropriately obstructing the passage of the plasma.

[0022] In addition, a seventh configuration of the present invention is the sixth configuration, wherein the anode auxiliary member includes a rod-shaped member protruding from the protruding piece and having an axis in an angular direction relative to the protruding direction of the protruding piece.

[0023] In the above configuration, the anode auxiliary member is composed of a rod-shaped member having an axis angled with respect to the direction in which the protrusion protrudes from the anode section, allowing electrons contained in the plasma to reach the surface of the rod-shaped member. The rod-shaped member may be integral with the protrusion, or may be a separate member protruding from the protrusion while electrically connected. The larger the surface area accessible to electrons contained in the plasma, the lower the positive column resistance, contributing to the stabilization of the vacuum arc discharge. To reduce the resistance between the electrodes without significantly impeding the passage of the plasma flow, the axis of the rod-shaped member is preferably arranged parallel to the direction of passage of the plasma flow, but this direction is not limited to this. Furthermore, the rod-shaped member protrudes from the protrusion toward the downstream side of the plasma flow, allowing it to be positioned without considering its relationship with the cathode section and other surrounding components. However, if there is adequate space upstream, the rod-shaped member may also protrude toward the upstream side.

[0024] In an eighth configuration of the present invention, in the fifth configuration, the anode auxiliary members are provided at a plurality of arbitrarily set positions at appropriate intervals in the circumferential direction of the anode portion forming the hollow shape.

[0025] According to the above configuration, multiple anode auxiliary members can be provided around the hollow anode section. In this configuration, since plasma passes through the hollow anode section, the passage of the passing plasma is obstructed at multiple locations around the anode section. However, this expands the location and area that electrons contained in the plasma can reach, thereby reducing the resistance between the cathode and anode and contributing to the stabilization of the vacuum arc discharge. Furthermore, by limiting the protruding length and size of the anode auxiliary members so as not to significantly obstruct the passage of the plasma flow, it is possible to adjust the size of the anode auxiliary members so as not to significantly obstruct the passage of the plasma flow and to increase only the area that electrons can reach.

[0026] A ninth configuration of the present invention is the sixth configuration, wherein the protruding piece is configured as a shielding portion having a surface of an appropriate area and arranged to shield part of the hollow shape formed by the anode portion.

[0027] According to the above configuration, the protrusion is formed by a shielding portion having an appropriate surface area, thereby shielding a portion of the hollow shape of the anode portion, thereby reliably obstructing the passage of the plasma flow and defining a location where electrons contained in the plasma can reach. Here, "shielding a portion of the hollow shape" refers to a state in which a portion of the hollow cross section is eroded. For example, if the hollow cross section of the hollow shape of the anode portion is circular, this refers to a state in which the area formed by an arc between any two points on the circumference and the chord connecting those two points is shielded so as to exclude it from the hollow cross section. In this example, the shielding portion can be configured as a rectangle, and one side of the rectangular shielding portion can be positioned at the position of the chord to shield a portion of the circular hollow cross section. Note that the shielded area in the above example may also be crescent-shaped.

[0028] The tenth configuration of the present invention is the ninth configuration, wherein the shielding portion is composed of a plurality of shielding plates and is arranged to shield the hollow interior formed by the anode portion at a plurality of locations.

[0029] According to the above configuration, since a plurality of shielding plates are provided inside the hollow shape through which the plasma flow must pass, it is possible to set a plurality of locations at which electrons contained in the plasma can reach. With this configuration, the electrons contained in the plasma can reach the shielding portion electrically connected to the anode portion at a plurality of locations, thereby reducing the resistance between the cathode and the anode.

[0030] An eleventh configuration of the present invention is the tenth configuration, wherein the plurality of shielding plates constituting the shielding portion are arranged in line symmetry with respect to an arbitrary straight line on the annular cross section passing through the center point, in the annular cross section of the anode portion forming a hollow shape inside.

[0031] According to the above configuration, the anode section basically has a moderate thickness and is hollow inside, so that it is formed with an overall circular cross section. Therefore, by providing shielding plates at positions (multiple locations) on the circular cross section that are line-symmetrical with respect to a line passing through the center point, it is possible to set locations on both sides where electrons contained in the plasma can reach when the plasma flow passes through. By providing shielding plates at symmetrical positions, for example, it is possible to provide shielding plates on either the left and right sides, the top and bottom sides, or both, and therefore it is possible to adjust the state of the plasma flow obstructed by the shielding plates so that it is not biased toward a specific position or direction.

[0032] Furthermore, the twelfth configuration of the present invention is the tenth configuration, wherein a plurality of shielding plates constituting the shielding portion are provided at a plurality of locations arbitrarily set with appropriate spacing in the circumferential direction of the anode portion forming the hollow shape.

[0033] In such a configuration, multiple shielding plates are provided at appropriate intervals around the circumference of the hollow shape, so if there is an imbalance in the state of passage of the plasma flow from the beginning, the state of passage of the plasma flow can be stabilized by appropriately selecting the positions at which the shielding plates should be installed.

[0034] The thirteenth configuration of the present invention is the sixth configuration described above, wherein the protrusion has one or more through holes drilled at appropriate locations. The fourteenth configuration of the present invention is the sixth configuration described above, wherein the protrusion is inclined, in part or in whole, toward the center of the inside of the hollow shape formed by the anode portion.

[0035] According to the above configuration, the installation of the protrusions can form an area where electrons contained in the plasma can reach, while minimizing the obstruction of the passage of the plasma flow. In the invention according to the thirteenth configuration, the position, number, and size of the through holes to be drilled are appropriately selected depending on the state of the plasma flow to pass through. Similarly, in the invention according to the fourteenth configuration, the area to be inclined of the protrusions and the inclination direction (inclination angle) are also appropriately selected depending on the state of the plasma flow to pass through. These configurations are the same when installing one protrusion as when installing multiple protrusions.

[0036] According to the present invention, since the anode section has a hollow shape, the plasma is guided to pass through the hollow interior of the anode section, and the anode auxiliary member protrudes into the hollow interior of the anode section to create a state in which the passage of the plasma flow is obstructed, thereby creating a state in which some of the electrons emitted from the cathode point come into contact with the anode auxiliary member together with the plasma. This allows the electrons contained in the plasma to reach the anode auxiliary member and move to the anode section, thereby reducing the resistance between the cathode and anode, and ultimately reducing the arc voltage and stabilizing the vacuum arc discharge.

[0037] FIG. 1 is an explanatory diagram showing an outline of a film formation apparatus. FIG. 1 is an explanatory diagram showing the configuration of a magnetic field generator in the film formation apparatus. FIG. 2 is an explanatory diagram showing a configuration for protecting the magnetic field generator. FIG. 3 is an explanatory diagram showing the configuration for protecting the magnetic field generator. FIG. 4 is an explanatory diagram showing an outline of an embodiment of an arc discharge stabilization structure. FIG. 5 is an explanatory diagram showing an outline of an embodiment of an arc discharge stabilization structure. FIG. 6 is an explanatory diagram showing the basic configuration of an anode auxiliary member. FIG. 7 is an explanatory diagram showing the basic configuration of an anode auxiliary member. (a) shows the configuration of the cathode part and the anode part used in the experimental apparatus, (b) shows the state of the protruding piece used in the first experiment, and (c) shows the state of the shielding plate used in the second experiment. FIG. 8 is an explanatory diagram showing a modified form of the anode auxiliary member. FIG. 9 is an explanatory diagram showing a modified form of the anode auxiliary member.

[0038] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. First, the overall structure of a film forming apparatus will be briefly described, and then the details will be described.

[0039] <Overall Structure of Film Forming Apparatus> Figure 1 is a diagram showing an outline of a film forming apparatus. The film forming apparatus according to the present invention is generally configured to include a plasma generating means 1, a plasma duct 2 that serves as a transport path for particles formed by evaporation of a cathode material by the plasma generating means, and a film forming chamber 3 for forming a film. The film forming chamber 3 is provided inside a vacuum chamber 4. The plasma generating means 1 includes a cathode portion 11 and an anode portion 12 provided nearby. The cathode portion 11, the anode portion 12, and the plasma duct 2 are provided inside the same vacuum chamber 4 as the film forming chamber 3. The cathode portion 11 and the anode portion 12 are connected to an external arc power source 13 via insulated lead-in terminals 5 installed on the wall surfaces of the vacuum chamber 4, respectively, enabling arc discharge between the cathode portion 11 and the anode portion 12.

[0040] The cathode section 11 is provided with a cathode 11A made of a film-forming material, which corresponds to a target (evaporation material raw material). While the cathode 11A is configured to double as a target, the film-forming material serving as the target may be separately disposed on the surface of the cathode 11A. The material of the cathode 11A, which doubles as a target, is not particularly limited as long as it is a conductive solid, and may include a metal, alloy, inorganic element, inorganic compound, etc. These may be used alone or as a mixture of two or more types. For example, all typical metals and transition metals may be used as metal elements. Among these, Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Ag, In, Sn, Sb, Hf, Pt, Au, Hg, Pb, Nd, Ta, W, Mo, etc. Examples of alloys or intermetallic compounds include TiAl, TiCr, TiSi, AlSi, AlCr, and NdFe. Examples of inorganic simple substances include C (graphite), and examples of inorganic compounds (ceramics) include TiO. ２ , ZnO, SnO ２ , ITO (Indium-Tin-Oxide), In ２ O ３ , Cd ２ SnO ４ , CuO, and other oxides. Further examples include carbides and nitrides such as TiN, TiAlC, TiC, CrN, and TiCN. Mixtures of two or more of these are also possible. Materials that can be mixed with the cathode 11A in a range that maintains its conductivity (semiconductor-like or semimetallic) include non-metallic materials, such as B, C, Si, P, Ge, As, Se, Sb, Te, Bi, Po, and At. Examples of atmospheric gases include He, Ar, H ２ , N ２ , O ２ Examples of gases include fluorine gas, hydrocarbon gas, chloride gas, sulfide gas, and mixtures thereof, and gases or liquid vapors containing fluorine, hydrogen, carbon, chlorine, sulfur, boron, phosphorus, etc. may also be introduced.

[0041] The anode portion 12 may be made of any conductive material that can withstand temperatures of approximately 200°C, and is not limited to this material. Metals, alloys, inorganic elements, inorganic compounds, etc. may be used, and the materials exemplified for the cathode may be appropriately selected and used. These may be used alone or as a mixture of two or more types. For example, stainless steel, soft iron, steel, copper, copper alloys, aluminum, aluminum alloys, graphite, tungsten, molybdenum, etc. may be used.

[0042] A trigger electrode 14 is provided near the cathode 11A, and is used to induce a vacuum arc between the cathode section 11 and the anode section 12 (anode 12A). That is, the trigger electrode 14 is temporarily brought into contact with the surface of the cathode 11A and then pulled away, generating an electric spark between the cathode 11A and the trigger electrode 14. When an electric spark is generated, the electrical resistance between the cathode 11A and the anode 12A decreases, generating a vacuum arc between the electrodes 11A and 12A. In addition, a first magnetic field generator 15 is installed around the cathode section 11. This magnetic field generator 15 generates a magnetic field around the cathode unit 11 to stabilize the cathode point of the vacuum arc and the plasma generated by the arc discharge. However, as described below, when the anode unit 11 includes (or is composed of) a protective member, the cathode 11A and the anode 12A cannot be spaced closely together, and the vacuum arc discharge may not be sufficiently stabilized (the number of times the arc is extinguished per a given time may increase) with only the first magnetic field generator 15. Note that although the first magnetic field generator 15 is shown installed outside the chamber in the figure, it may also be installed inside the chamber or behind the cathode unit 11. Multiple units may also be installed, as long as they are installed so that a magnetic field that efficiently transports the plasma flow X is applied to the surface of the cathode 11A (including the front surface of the cathode 11A).

[0043] The region that serves as the transport path for evaporated particles is formed inside the anode section 12, which is formed in a substantially cylindrical shape. As will be described in detail later, a second magnetic field generator 6 using an electromagnet is provided on the outer periphery of the substantially cylindrical anode section 12, generating an induced magnetic field that guides charged particles generated by evaporation of the film-forming material in a predetermined direction. This induced magnetic field is oriented along the central axis of the substantially cylindrical anode section 12. The charged particles are guided in the region that serves as the transport path in a linear direction from the cathode section 11 along the central axis of the substantially cylindrical anode section 12, and the charged particles are supplied to the workpiece A inside through the opening 31 of the film-forming chamber 3 located in front.

[0044] The film formation chamber 3 is open (continuous inside the vacuum chamber 4) on the side facing the plasma generation means 1 (near the end of the plasma duct 2), and inside the film formation chamber 3, a plurality of workpieces (works) WK1, WK2, ... are held on work holders (not shown) provided on a rotary work table 32. The rotary work table 32 rotates intermittently, so that the plurality of workpieces (works) WK1, WK2, ... can be sequentially brought face to face with the plasma generation means 1 and subjected to film formation processing.

[0045] In the vacuum arc discharge that forms the plasma flow X, droplets are simultaneously emitted from the cathode spot in addition to electrons and cathode material evaporation particles. At this time, the cathode material evaporation particles collide with the electrons emitted from the cathode spot, ionizing the material and generating metal ions and / or nonmetal ions. The cathode material evaporation particles are ionized by collision with the electrons immediately after being emitted from the cathode spot. Neutral particles, such as non-ionized cathode material evaporation particles (excluding those that subsequently ionize), introduced gas particles, and reactive particles, are generated, and they travel in a straight line in the initial direction of emission without being affected by the magnetic field or electric field. Meanwhile, droplets are emitted by bumping at the cathode, but because they do not carry an electric charge, they also travel in a straight line without being affected by the magnetic field or electric field.

[0046] As described above, the second magnetic field generator 6 is provided on the outer periphery of the substantially cylindrical anode 12 to generate an induction magnetic field that guides charged particles generated by evaporation of the film formation material in a predetermined direction. The induction magnetic field generated by this second magnetic field generator 6 need only be arranged so as to be oriented along the central axis of the substantially cylindrical anode 12, and Fig. 1 shows a configuration in which it is installed outside the vacuum chamber 4. The magnetic field generator 6 is solely an electromagnet, and therefore a DC voltage is applied to it.

[0047] Because of the above-described configuration, the second magnetic field generator 6 may be installed inside the vacuum chamber 4 as shown in FIG. 2( a), or, as shown in FIG. 2( b), the second magnetic field generator 5 may be installed inside the vacuum chamber 4, with part of the components constituting the anode section 12 being coiled or with a coil-shaped component connected to the anode section 12, and a magnetic field may be applied by causing a self-current due to arc discharge generated between the cathode 11A and the anode 12A to flow through the coil-shaped component.

[0048] When a coiled member is provided in the anode section 12, the anode is configured with a cylindrical protective member, which allows droplets (by-product fine particles) to adhere to the protective member, thereby protecting the coiled member. While several types of protective member installation structures are possible, the protective member is positioned in a manner that protects the second magnetic field generator 6, which is formed as a coiled member, from droplets (by-product fine particles). Here, the term "protective member" is used to refer to the prevention of droplets and film adhesion to the coiled member, but it is also electrically connected to the anode without resistance and functions as an electron receptacle. Therefore, electrically, it is a current collecting member that handles most of the current and is part of the anode. Therefore, hereinafter, the protective member may be referred to as the "current collecting member."

[0049] Here, we will explain exemplary configurations of typical protective members (current collecting members). Specifically, the protective member 7 (7a, 7b) shown in FIG. 3(a) comprises annular (hollow) annular plates 7a, 7b disposed at both ends of a coiled member (second magnetic field generator) 6. The coiled member 6 is connected to the annular plates 7a, 7b at both ends by conductors 71a, 71b, so that the two plates are electrically connected. The annular plate 7a, located on the cathode 11 side, protects the coiled member 6 by adhering droplets (by-product fine particles) emitted toward the coiled member 6. The annular plate 7b on the opposite side adheres droplets (by-product fine particles) that pass through gaps in the coiled member 6, thereby preventing the droplets from scattering and protecting the coiled member 6 from re-approaching after being reflected by various parts. When the protective member made of the annular plates 7a and 7b functions as a current collecting member that is responsible for the inflow of electrons, the annular plate 7a closer to the cathode portion 11 is able to receive a larger electron current than the other annular plate 7b.

[0050] 3(b) is configured such that, in addition to the annular plates 7a and 7b, a member 72 is fixed that is an integral member of a flange portion 72a and a cylindrical portion 72b connected to one of the annular plates 7a arranged on the cathode portion 11 side. The flange portion 72a is for supporting the cylindrical portion 72b, and by fixing this flange portion 72a to one of the annular plates 7a, the coil-shaped member 6 is protected by the cylindrical portion 72b. Note that, since the coil-shaped member 6 is configured to be protected by the cylindrical portion 72b, it is also possible to fix the flange portion 72a to the other annular plate 7b as shown in FIG. 4(a). In these cases, the protective member as a whole functions as a current collecting member, and therefore, electron current can be received not only at the end face of the flange portion 72a but also at the inner circumferential surface of the cylindrical portion 72b.

[0051] 4(b), in addition to the annular plates 7a and 7b, a substantially cylindrical dust cover 73 may be provided to surround the outer periphery of the coiled member 6. Basically, the provision of the annular plates 7a and 7b protects the coiled member 6, but this dust cover is used in cases where a large amount of droplets (by-product fine particles) are emitted, and a large number of droplets (by-product fine particles) pass through the gaps in the coiled member 6, and it is necessary to prevent them from re-approaching due to reflection.

[0052] <Embodiment of Overall Structure> Here, an outline of this embodiment of the vacuum arc discharge stabilization structure of the present invention will be described. Figures 5 and 6 show an outline of this embodiment of the arc discharge stabilization structure. These figures illustrate three representative configurations of the second magnetic field generator 6, and Figure 6 illustrates only two of the various configurations of the protective member (current collecting member) 7 (7a, 7b, 72a, 72b, 73) shown above.

[0053] The first embodiment of the vacuum arc discharge stabilization structure is a configuration in which a magnetic field generator 6 is disposed outside a vacuum chamber 4, as shown in Figure 5(a). The anode section 12 is formed in a hollow shape, and is basically cylindrical in the figure. The hollow shape allows the plasma flow converged by the magnetic field generator 6 to be guided into the hollow interior. Note that the shape of the anode section 12 need only be a shape with a hollow interior into which the plasma flow can be injected, and it can be other tubular shapes other than a cylindrical shape, or it can be a ring shape or other annular shape.

[0054] In this embodiment, an anode auxiliary member 8 is provided on the anode section 12 having such a configuration, protruding from the cathode-side end face or inner peripheral surface toward the inside of the hollow shape. The specific shape of the anode auxiliary member 8 will be described later. When electrically connected to the anode section 12, the anode auxiliary member 8 protrudes into the approximately cylindrical (hollow) shape formed by the anode section 12, thereby obstructing the passage of the plasma flow X. The anode auxiliary member 8 may be provided in a single piece or in multiple pieces. It may simply protrude linearly into the hollow interior in the radial direction, or may be partially angular in the radial direction. The basic shape of the anode auxiliary member 8 may be flat, but is not limited thereto, as long as it has an appropriate area. Therefore, the radially angular portion may be flat, but is not limited thereto and may be rod-shaped (e.g., round bar). The angular portion may be integral with another portion, or may be individually configured and joined to form an electrically connected portion. At this time, it is preferable that the electrical connection be in a state where there is no resistance.

[0055] As shown in Fig. 5(b), the second embodiment of the vacuum arc discharge stabilization structure is basically the same as the above, with a magnetic field generator 6 disposed around an anode unit 12 having a hollow shape, typically a cylindrical shape, but differs in that the magnetic field generator 6 is installed inside a vacuum chamber. In this case, too, the anode auxiliary member 8, when electrically connected to the anode unit 12 (connected without a resistor), protrudes into the approximately cylindrical (hollow) shape formed by the anode unit 12, thereby obstructing the passage of the plasma flow X. Note that installing the magnetic field generator 6 inside the vacuum chamber makes it possible to shorten the distance from the cathode unit 11 to the workpiece (see Fig. 2(a)).

[0056] A third embodiment of the vacuum arc discharge stabilization structure uses a protective member (current collecting member) that includes annular plates 7a and 7b, as shown in FIG. 6( a). In this embodiment, an anode auxiliary member 8 protrudes from one of the annular plates 7a toward the hollow interior of the annular ring (inside the hollow shape). The specific shape of the anode auxiliary member 8 will be described later. When electrically connected to the annular plate 7a, the anode auxiliary member 8 protrudes into the approximately cylindrical (hollow) shape formed by the anode portion 12, thereby obstructing the passage of the plasma flow X. As in the case where a protective member (current collecting member) is not provided, the anode auxiliary member 8 may be provided in a single unit or in multiple units. The anode auxiliary member 8 may simply protrude radially linearly into the hollow interior, or may be partially angular in the radial direction.

[0057] As shown in FIG. 6( b), a fourth embodiment of the vacuum arc discharge stabilization structure includes annular plates 7a and 7b, a flange 72a, and a cylindrical portion 72b. The flange 72a is joined to one of the annular plates 7a to form a protective member (current collecting member). In this embodiment, an anode auxiliary member 8 is provided that protrudes from the inner circumferential surface of the cylindrical portion 72b, thereby obstructing the passage of the plasma flow X. The anode auxiliary member 8 may be located not only on the inner circumferential surface of the cylindrical portion 72b but also protrudes from the flange 72a into the hollow interior. The shape and number of the anode auxiliary members 8 can be selected as appropriate, and their positions on the inner circumferential surface of the cylindrical portion 72b can also be adjusted as appropriate. In this embodiment, the anode auxiliary member 8 is electrically connected to the cylindrical portion 72b (connected without a resistor), and the cylindrical portion 72b is further electrically connected to the annular plate 7a via the flange 72a.

[0058] According to the above-described embodiments, the anode auxiliary member 8 is provided so as to protrude toward the hollow interior of the annular plate 7a or the cylindrical portion 72b, thereby preventing the plasma flow X from passing through the hollow interior (blocking the passage of the plasma flow X). Therefore, the anode auxiliary member 8 is subjected to collisions with various particles contained in the plasma, which may result in the adhesion of droplets (by-product fine particles), but it also allows electrons contained in the plasma to reach the anode auxiliary member 8. When the electrons reach the anode auxiliary member 8, the positive column resistance decreases, thereby reducing the overall resistance between the cathode and the anode. This reduces the arc voltage and stabilizes the vacuum arc discharge. In the case of a configuration in which the protective member (current collecting member) 7 is not provided (see FIGS. 5(a) and 5(b)), electrons also reach the cylindrical anode portion 12, and in the case of a configuration in which the protective member (current collecting member) 7 is provided (see FIGS. 6(a) and 6(b)), the protective member (current collecting member) 7 also receives electrons, but the provision of the anode auxiliary member 8 assists the electrons from reaching the anode portion 12. In this sense, the anode auxiliary member 8 functions as a current collecting auxiliary member.

[0059] <Configuration of Anode Auxiliary Member (Current Collector Auxiliary Member)> Next, the configuration of the anode auxiliary member (current collector auxiliary member) used in the above-described embodiment will be described. Basic configurations are illustrated in FIGS. 7 to 9, and modified examples are illustrated in FIGS. 11 to 14. In each figure, the left side shows a side view of the anode unit from the cathode unit side, and the right side shows a longitudinal cross section (a cross section along the arrow line). The basic configuration examples (FIGS. 7 to 9) are described using a configuration (installed in a vacuum chamber) with an anode unit 12 having a coil-shaped member 6 as a representative example of the configurations of the above-described embodiments, but the same configurations can also be used for the embodiments with the above-described configurations.

[0060] First, in a first embodiment of the anode auxiliary member (current collecting auxiliary member), as shown in Fig. 7(a), a single protrusion 81 is fixed to the surface of one of the annular plates 7a. This protrusion 81 is formed in the shape of a thin, approximately rectangular plate, with a portion of the back side (base end side) in close contact with (electrically connected to) the surface of the annular plate 7a and a tip (free end side) protruding into the hollow interior H of the annular plate 7a (anode portion 12). Even with a single protrusion 81, by appropriately protruding into the hollow interior H, the surface (one side) is positioned in a state in which it obstructs the flow of plasma, thereby forming an area into which electrons contained in the plasma can reach.

[0061] As shown in FIG. 7( b ), the second form of the anode auxiliary member (current collecting auxiliary member) uses a single protruding piece 82, as described above, with a through-hole (long hole) 83 drilled at an appropriate position in the protruding piece 82. The provision of the through-hole 83 allows the plasma flow to pass while partially obstructing it, thereby forming an area where electrons can reach. By enlarging the opening of the through-hole 83, the plasma flow can pass through while the tip (free end side) can reach near the center of the hollow interior H, thereby ensuring an area where electrons can reach.

[0062] As shown in FIG. 8( a), the third embodiment of the anode auxiliary member (current collecting auxiliary member) has a rod-shaped member (a round rod in the figure) 85 protruding from the back side of the protrusion 84. The rod-shaped member 85 is fixed (electrically connected) to the back side of the protrusion 84 and supported with its axis protruding toward the downstream plasma flow. The protrusion 84 has a configuration similar to the protrusion 81 (see FIG. 7( a)) in the first embodiment. Therefore, primarily, the surface of the protrusion 84 obstructs the passage of the plasma flow, forming a region where electrons can reach. Secondarily, the surface of the rod-shaped member 85 comes into contact with the plasma, thereby expanding the region where electrons can reach. Note that, although the axis of the rod-shaped member 85 in the figure is parallel to the center line C of the hollow interior H, the direction of this axis does not need to be parallel to the center line C and may be tilted.

[0063] In the fourth embodiment of the anode auxiliary member (current collecting auxiliary member), as shown in FIG. 8( b), two protrusions 86 and 87 are fixed to the surface of the annular plate 7a. The protrusions 86 and 87 are configured similarly to the protrusion 81 (see FIG. 7( a)) in the first embodiment. The protrusions 86 and 87 can be provided at multiple locations, and all of them are electrically connected to the annular plate 7a to allow electrons to move. Furthermore, these multiple protrusions 86 and 87 do not need to be provided symmetrically, and can be arbitrarily selected at locations that facilitate fastening. Therefore, they can be provided at the locations indicated by the dashed lines in the figure, and additional protrusions 88 and 89 may be provided at these locations, or two or three of the four locations in the figure may be arbitrarily selected.

[0064] A fifth embodiment of the anode auxiliary member (current collecting auxiliary member) is shown in FIG. 9( a) and is constituted by plate-shaped shielding plates 91, 92 having a relatively large area. The illustrated shielding members 91, 92 are formed of rectangular plate-shaped members, but any shape is acceptable as long as they can be installed to shield an appropriate proportion of the hollow interior H of the annular plate 7a (anode unit 12). While the shielding members 91, 92 are symmetrically arranged on both the left and right sides, symmetry is not essential as long as they can shield an appropriate proportion of the entire hollow interior H. Therefore, for example, a single shielding plate 91 may be used to enlarge the shielding area. Note that the term "shielding plate" as used herein refers to a plate arranged to reduce the diameter of the hollow interior H. Therefore, when a plasma flow passes through the hollow interior H of the anode unit 12, the outer periphery of the plasma flow temporarily contracts. This contraction of the plasma flow allows electrons contained in the plasma to easily reach the shielding plates 91, 92.

[0065] As shown in FIG. 9( b), a sixth embodiment of the anode auxiliary member (current collecting auxiliary member) is configured by fastening shielding plates 93, 94, each having a rectangular shape with the shorter sides shorter than those of the shielding plates 91, 92, to the annular plate 7a. By positioning the shielding plates 93, 94 with such shapes close to the center of the annular plate 7a, a space can be formed between the inner peripheral edge 70 of the annular plate 7a and the shielding plates 93, 94. This function allows the shielding plates 93, 94 to contract the outer periphery of the plasma flow while allowing the plasma that cannot contract and flow into the cylindrical interior H to pass through. In the configuration of the present invention, the shielding plates are conceptualized as a type of protrusion (one form of protrusion), and therefore the shielding plates 93, 94 in this case can be recognized as a modified version of the multiple protrusions 86, 87 (see FIG. 8( b)). That is, when these types of shielding plates 93, 94 are installed, they are a compromise between the above-mentioned projections 86, 87 and the shielding plates 91, 92 shown in the fifth embodiment (FIG. 9(a)).

[0066] The basic forms of the anode auxiliary member (current collecting auxiliary member) have been shown above, but in any form, the protrusions 81 to 89 and the shielding plates 91 to 94 are configured so that their surfaces, each with an appropriate area, obstruct the passage of the plasma flow, thereby allowing the electrons contained in the plasma to reach them.

[0067] <Experimental Example Regarding Vacuum Arc Discharge Stabilization> With regard to the basic configuration described above, experiments were conducted regarding the stability of vacuum arc discharge for the second form of anode auxiliary member (a configuration having a protrusion 82 (see FIG. 7(b)) and its modifications) and the fifth form (a configuration having shielding plates 91, 92 (see FIG. 9(a))). The film formation apparatus used in the experiments was configured so that a cathode part 11 and an anode part 12 were installed inside a vacuum chamber. A first magnetic field generator 15 was installed outside the vacuum chamber. The cathode part 11 and anode part 12 used in the experimental apparatus were configured so that a coil-shaped member 6 was formed on the anode part 12, as shown in FIG. 10(a), and a second magnetic field generator was used in which the coil-shaped member 6 was capable of applying a magnetic field by its own current, and each of the protrusions 82 or shielding parts 91, 92 was fixed to the surface of one of the annular plates 7a.

[0068] The polarity of the magnetic field applied by the second magnetic field generator (coil-shaped member) 5 was set to N in the direction of travel of the plasma flow X, while the first magnetic field generator 15 applied a magnetic field with N in the opposite direction. In one of the experimental examples described below, a magnetic field generator 16 was also installed behind the cathode. This magnetic field generator 16 was installed outside the vacuum chamber, and the polarity of the magnetic field was the same as that of the second magnetic field generator. The dimensions and other conditions of each of the protrusions 82 and shielding plates 91 and 92 will be described individually below.

[0069] First Experimental Example: The first experimental example uses a protruding piece 82 as shown in FIG. 10(b). The diameter of the hollow interior H of the annular plate 7a (the inner diameter of the annular plate 7a) was 130 mm, and the diameter of the coil-shaped member 6 was 196 mm. The protruding piece 82 was made of oxygen-free copper, had a thickness of 3 mm, and a width dimension W1 of 10 mm. As described above, the protruding piece 82 had a through hole (long hole) 83, and the dimension W2 on the short side of the through hole 93 was 3 mm. The protruding length L1 from the inner surface of the hollow interior H was 0 mm (when not protruding) and 30 mm (when protruding). Other major conditions were as shown in the table below.

[0070]

[0071] Under the above conditions, arc discharge was carried out for one minute when the protrusion length L1 of the protrusion 82 was 0 mm and when it was 30 mm, and the number of times the arc was extinguished during that time was counted. The above was repeated twice and the average was taken as the experimental result. The results are as shown in the table below. Note that the "ON" state of the coil-shaped member indicates a state in which a magnetic field is applied by the second magnetic field generator 6.

[0072]

[0073] According to the above results, the situation where the protrusion length (L1) of the protrusion 82 is 0 mm is the same as the situation where the protrusion 82 is not provided, and so it was found that the number of arc extinctions per minute in this case was 17 times on average, but when the protrusion 82 was extended by 30 mm, this number was significantly reduced to 9 times. Similarly, the arc voltage also decreased from 31 V to 29 V, confirming that the arc discharge was stabilized.

[0074] Second Experimental Example: In the second experimental example, the flat protruding piece 84 illustrated in FIG. 8(a) was used instead of the protruding piece 82 shown in FIG. 10(b). Other conditions, except for the protruding piece 84, were the same as those in the first experimental example. The diameter of the hollow interior H of the annular plate 7a (the inner diameter of the annular plate 7a) was 130 mm, and the diameter of the coil-shaped member 6 was 196 mm. Unlike the protruding piece 82 in the first experimental example, the protruding piece 84 was a rod-shaped member 85 protruding from it without a through-hole 83. The rod-shaped member 85 had a diameter of 8 mm and a length of 50 mm. Both the protruding piece 84 and the rod-shaped member 85 were made of oxygen-free copper. The protruding piece 84 had a wall thickness of 3 mm, a width W1 of 10 mm, and a protruding length L1 of 30 mm from the inner surface of the hollow interior H. Other major conditions were the same as those in the first experimental example (Table 1). Under the above conditions, arc discharge was performed twice for one minute, and the number of times the arc was extinguished during that time was counted and the average was taken as the experimental result. The results are shown in the table below.

[0075]

[0076] The above results show that the effect is almost the same as, or even greater than, the first experimental example using only the protrusion 82. Compared to the state of the first experimental example "No. 1," the number of arc extinctions was significantly reduced, and the arc voltage was reduced from 31 V to 28 V, confirming that the arc discharge was stabilized.

[0077] Third Experimental Example The third experimental example used shielding plates 91, 92 as shown in FIG. 10(c). The diameter of the hollow interior H of the annular plate 7a (the inner diameter of the annular plate 7a) was 130 mm, the same as in the experimental example, and the diameter of the coil-shaped member 6 was 196 mm, the same as in experimental example 1. The shielding plates 91, 92 were made of stainless steel and had a wall thickness of 4 mm. In addition, they were arranged so that the protruding length L2 from the inner peripheral surface of the hollow interior H varied in 10 mm increments within a range from 0 mm (no protrusion) to 30 mm. The protruding lengths of the two shielding plates 91, 92 were the same on the left and right. Other main conditions were as shown in the table below.

[0078]

[0079] Under the above conditions, arc discharges were conducted for 20 minutes each while varying the shielding length L2 of the shielding plates 91, 92 from 0 mm to 30 mm, and the number of times the arc was extinguished during that time was counted. Experiments were also conducted with and without applying a magnetic field to the anode 12 by the coil-shaped member (second magnetic field generator) 5 used in the non-protruding state of the shielding plates 91, 92. The results are shown in the table below. The "ON" state of the coil-shaped member is the same as in the first experiment, and the "OFF" state indicates a state in which the magnetic field is not applied by the second magnetic field generator 6 (specifically, the annular plates 7a, 7b on both sides are short-circuited, preventing current from flowing through the coil 6 to induce a magnetic field).

[0080]

[0081] According to the above results, even when the protrusion length (L2) of the shielding plates 91 and 92 was relatively small (10 mm, No. 6) compared to 0 mm (no protrusion, No. 5), the arc voltage was lower and the average number of arc extinctions per minute was significantly reduced. Furthermore, when the protrusion length was approximately 20 mm (No. 7), the number of arc extinctions was even lower. With protrusion lengths (L2) of 20 mm and 30 mm (Nos. 7 and 8), a decrease in arc voltage was confirmed, but a reduction in the number of arc extinctions was not confirmed. This indicates that a protrusion length (L2) of 20 mm or more is preferable. The numerical values ​​of the above experimental results may vary depending on the device, as they depend on the original anode inner diameter and the magnetic field around the anode.

[0082] It is noted that when no magnetic field is generated by the coil-shaped member 6 (No. 4), the arc voltage is low and the number of times the arc is extinguished is also small, but this is because the plasma flow is not converged because no magnetic field is applied by the second magnetic field generator. The present invention relates to a structure for stabilizing the arc discharge when the plasma flow is converged by applying a magnetic field by the second magnetic field generator, and a comparison of only the results of the number of times the arc is extinguished confirms that when the shielding plates 91, 92 protrude by 20 mm or more, the plasma flow is more stable than when it is not converged.

[0083] <Summary> The above experimental results confirmed that the number of arc extinctions occurring within a predetermined discharge time decreased in both cases, when the protruding piece 82 was protruding (first experimental example), and when the hollow interior H was shielded by the shielding plates 91, 92 (second experimental example), and it became clear that the arc discharge was stabilized. Therefore, it can be easily understood that the arc discharge can be similarly stabilized even in the case of a configuration that replaces the protruding piece 82 and the shielding plates 91, 92 used in the experimental examples.

[0084] <Modifications of the Shape of the Anode Support Member> Next, modifications of the shape of the anode support member shown above will be described. Note that, based on the results of the above experimental example, these modifications were made as a means to form a region that blocks the passage of the plasma flow, but are not limited to these, and various configurations are possible with regard to other shapes, quantities, positions, and sizes.

[0085] First, the first modified example is shown in Figure 11(a). This modified example is a modification of the fourth embodiment. Specifically, four protrusions 86-89 are arranged approximately evenly (at equal intervals) around the circumference of the annular plate 7a, and the tips (free ends) are sharply pointed. To achieve the sharpened shape, the overall planar shape is triangular, with one vertex positioned at the tip (free end).

[0086] A second modified example is shown in FIG. 11( b). This modified example is essentially a modification of the fourth embodiment, incorporating elements of the third embodiment. Specifically, two protrusions 86, 87 are used, each of which is angled toward the inside of the anode unit 21 (the hollow interior H). Specifically, each protrusion 86, 87 is composed of a fixed portion 86a, 87a and a cornered portion 86b, 87b. The cornered portions 86b, 87b are angled and extend from the tip of the fixed portion 86a, 87a in the longitudinal direction of the hollow interior H of the anode unit 12. Similar to the rod-shaped member 85 (see FIG. 8( a)) shown in the third embodiment, the cornered portions 86b, 87b are oriented in the direction of the plasma flow (toward the center line C of the hollow interior H). While not parallel to the center line C of the hollow interior H, they may be arranged parallel.

[0087] The third modified example is the configuration shown in FIG. 12( a). This modification is a variation of the second embodiment. While the second modified example had a through-hole (long hole) 83 provided in the protruding piece 82, this long hole 83 is configured as multiple individual round through-holes 83a, 83b, and 83c. Even with this configuration, the through-holes 83a-83c can be used to form a region through which the plasma flow can pass. Note that the through-hole 83c at the base end does not reach the hollow interior H of the annular plate 7a and therefore does not contribute to forming the plasma flow passage region. However, this through-hole 83c may be used for fastening between the annular plate 7a and the protruding piece 82, for example, as an insertion hole for a conductor bolt. Furthermore, if the through-holes 83a-83c are positioned symmetrically in the longitudinal direction, they can be used even if their orientation in the protruding direction is reversed. Although three such through-holes 83b-83c are illustrated, the number is arbitrary.

[0088] 12(b), a fourth modified example is a further modification of the second modified example (see FIG. 11(b)). In this modified example, the fixed portions 86a, 87a of the protrusions 86, 87, each having a cornered portion 86b, 87b, are fixed to the other annular plate 7b. Even in this case, the cornered portions 86b, 87b penetrate into the hollow interior H of the anode 12, thereby obstructing the passage of the plasma flow and forming a region where electrons can reach.

[0089] The fifth to eighth modified examples are shown in FIGS. 13 and 14. These modified examples are examples in which the anode section 12 has a member 72 in which the flange section 72a and the cylindrical section 72b are integrated. That is, since the cylindrical section 72b of the anode section 12 is present inside the coil-shaped member 6, the plasma flow passes through the interior of this cylindrical section 72b. Therefore, the anode auxiliary member can be configured to protrude from the inner wall of the cylindrical section 72b. When protruding, it can be fixed by welding or the like, or it may be configured as an integrated structure in which the flange section 72a is fixed separately.

[0090] Therefore, the fifth modified example has a configuration in which a protrusion 84 and a rod-shaped member 85 are provided on the inner wall of the cylindrical portion 72b, as shown in Fig. 13(a). The protrusion 84 and the rod-shaped member 85 are configured in the same manner as in the third embodiment (see Fig. 8(a)), with the protrusion 84 protruding in the radial direction of the cylindrical portion 72b and the rod-shaped member 85 being disposed with its axis aligned with the center line C. The axis of this rod-shaped member 85 does not necessarily need to be parallel to the center line C. With this configuration, it is possible to obtain structural features similar to those of the third embodiment.

[0091] 13(b) shows a sixth modified example, which is a further modification of the fifth modified example. That is, in this embodiment, the anode auxiliary member formed by the protrusion 84 and the rod-shaped member 85 is moved to the longitudinal center of the cylindrical portion 72b. As described above, the position of the protrusion 84 and the rod-shaped member 85 can be freely selected as needed on the inner wall of the cylindrical portion 72b (this is not limited to this, and applies similarly to the case of only the protrusion 81), and therefore the installation position can also be selected arbitrarily.

[0092] The seventh modification is shown in Fig. 14(a), in which shielding plates 91, 92 are provided on the cylindrical portion 72b. The shielding plates 91, 92 shield the hollow interior H of the anode portion 12 to an appropriate extent, but the same effect can be achieved by installing them on the inner wall of the cylindrical portion 72b. Note that the illustrated state shows a state in which the two types of shielding plates 91, 92 are provided opposite each other and are offset in the longitudinal direction. In this way, when the inner wall of the cylindrical portion 72b is used freely, it is possible to deliberately change the positions of the two shielding plates.

[0093] 14(b), the eighth modified example is such that the protruding direction of the rod-shaped member 85 (in the configuration having the protruding piece 84 and the rod-shaped member 85) in the sixth modified example is reversed. Even in this configuration, the plasma flow passes through the hollow interior H of the cylindrical portion 72b, so that the electron arrival area can be secured.

[0094] <Summary> Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these. Therefore, the present invention can also be realized in configurations other than those illustrated above. That is, the present invention provides an anode section 12 having a hollow shape that allows the plasma flow to pass through. The anode auxiliary member protruding into the hollow shape obstructs the passage of the plasma flow. The anode auxiliary member is electrically connected to the anode, allowing electrons that reach the anode auxiliary member to flow through the anode, thereby reducing resistance (positive column resistance). Furthermore, because the vacuum arc discharge is stabilized as the arc voltage decreases, various configurations are possible as long as they can perform the above-described functions.

[0095] REFERENCE SIGNS LIST 1 plasma generating means 2 plasma duct 3 film formation chamber 4 vacuum chamber 5 insulating lead-in terminal 6 second magnetic field generating device (coil-shaped member) 7 protective member (current collecting member) 7a, 7b annular plate 8 anode auxiliary member (current collecting auxiliary member) 11 cathode portion 11A cathode 12 anode portion 13 arc power supply 14 trigger electrode 15 first magnetic field generating device 16 rear magnetic field generating portion 31 opening of film formation chamber 32 rotating work table 71a conductor 72a flange portion 72b cylindrical portion 73 dust cover 81, 82, 84, 86, 87, 88, 89 protrusion 83 through hole (long hole) 83a, 83b through hole (round hole) 91, 92, 93, 94 shielding plate C center line of hollow interior H Hollow interior L1, L2: Projection length W1, W2: Width WK1, WK2: Workpiece (processing object)

Claims

1. A film formation apparatus which comprises, within a vacuum chamber, a cathode, an anode placed at an appropriate distance from the cathode, and a magnetic field generator which applies a magnetic field to an anode part which constitutes the anode, and which generates a vacuum arc discharge between the cathode and the anode to evaporate the cathode material which constitutes the cathode, generates plasma containing the evaporated material, transports the plasma along the anode part, and deposits a film containing the raw material which constitutes the cathode material on the surface of a workpiece, wherein the anode part has a hollow shape which allows the plasma to pass through, and comprises an anode auxiliary member which is electrically connected to the anode and protrudes into the inside of the hollow shape.

2. A vacuum arc discharge stabilization structure for a film deposition apparatus according to claim 1, wherein the magnetic field generating device is formed in a substantially cylindrical shape outside the vacuum chamber so as to surround part or all of the anode portion.

3. A vacuum arc discharge stabilization structure for a film deposition apparatus according to claim 1, wherein the magnetic field generating device is provided within the vacuum chamber.

4. The vacuum arc discharge stabilization structure in a film deposition apparatus according to claim 3, wherein the magnetic field generating device is constituted by the anode portion or is electrically connected to the anode portion, and applies a magnetic field to the anode portion by a self-current caused by a vacuum arc discharge generated between the anode and the cathode, and the anode auxiliary member is electrically connected to either or both of the anode portion and the magnetic field generating device.

5. A vacuum arc discharge stabilization structure for a film deposition apparatus according to any one of claims 1 to 4, wherein the anode auxiliary member protrudes at least in one location into the hollow shape formed by the anode portion.

6. A vacuum arc discharge stabilization structure for a film forming apparatus as described in claim 5, wherein the anode auxiliary member has at least one protruding piece that protrudes from any position of the anode portion toward the inside of the hollow shape.

7. A vacuum arc discharge stabilization structure for a film forming apparatus as described in claim 6, wherein the anode auxiliary member comprises a rod-shaped member protruding from the protruding piece and having an axis in an angled direction relative to the protruding direction of the protruding piece.

8. A vacuum arc discharge stabilization structure in a film forming apparatus as described in claim 5, wherein the anode auxiliary members are provided at a plurality of locations arbitrarily set with appropriate spacing in the circumferential direction of the anode portion forming the hollow shape.

9. A vacuum arc discharge stabilization structure for a film forming apparatus as described in claim 6, wherein the protrusion has a surface of an appropriate area and is constituted by a shielding portion arranged to shield part of the hollow shape formed by the anode portion.

10. A vacuum arc discharge stabilization structure in a film forming apparatus as described in claim 9, wherein the shielding portion is composed of a plurality of shielding plates and is arranged to shield the hollow interior formed by the anode portion at multiple points.

11. A vacuum arc discharge stabilization structure in a film forming apparatus as described in claim 10, wherein the plurality of shielding plates constituting the shielding section are arranged in a state of line symmetry with respect to an arbitrary straight line on the annular cross section passing through the center point, in the annular cross section formed by the anode section forming a hollow shape inside.

12. A vacuum arc discharge stabilization structure in a film forming apparatus as described in claim 10, wherein the plurality of shielding plates constituting the shielding section are provided at a plurality of locations arbitrarily set with appropriate spacing in the circumferential direction of the anode section forming the hollow shape.

13. A vacuum arc discharge stabilization structure for a film deposition apparatus according to claim 6, wherein the protruding piece has one or more through holes drilled at appropriate locations.

14. A vacuum arc discharge stabilization structure for a film deposition apparatus according to claim 6, wherein the protruding pieces are partly or entirely inclined with respect to a direction toward the center of the inside of the hollow shape formed by the anode portion.

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