Arc evaporation source

Abstract

To provide an arc evaporation source capable of restraining generation of macro particles flying toward a workpiece by promoting movement of an arc spot on a target discharge surface.SOLUTION: An arc evaporation source 6 comprises a target 7 including a target discharge face 7S, an arc power source PS, an electromagnetic coil 8 arranged in front of the target 7, and a central magnet 20 arranged after the target 7. The electromagnetic coil 8 forms a first magnetic filed M1 including a first magnetic flux Q1 extending to cross with the target discharge face 7S and pass through radial inside of the electromagnetic coil 8 in a longitudinal direction. The central magnet 20 forms a second magnetic field M2 including a second magnetic flux Q2 extending in a region between the central magnet 20 and the target discharge face 7S in the longitudinal direction. A horizontal magnetic field and a vertical magnetic field are stably formed on the target discharge face 7S by repulsion of the first magnetic field M1 and the second magnetic filed M2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an arc evaporation source. [Background technology]

[0002] Various deposition methods using arc discharge have been proposed as a method for forming coatings on the surfaces of substrates such as tools and machine parts to improve their wear resistance. Patent Document 1 discloses a thin film deposition apparatus using such arc discharge. In this apparatus, arc adjusters composed of permanent magnets or electromagnets are placed in front of and behind the target. The vacuum chamber constitutes the anode of the arc discharge, and the holder supporting the target constitutes the cathode of the arc discharge, with an arc discharge voltage applied between the two electrodes. Each arc adjuster then forms magnetic field lines from the target toward the workpiece (the object to be deposited, the target to be deposited), causing the arc discharge to cause charged particles of the deposition material emitted from the target discharge surface to fly toward the workpiece and deposit thereon. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-280135 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 has a problem in that the arc spot is difficult to move on the target discharge surface, which easily generates macroparticles (also called droplets), which are clumps of coating material. These macroparticles adhere to the workpiece, worsening the surface roughness of the coating on the workpiece. Specifically, in the above technology, permanent magnets or electromagnets arranged around the target each generate magnetic field lines that pass through the target discharge surface in the same direction perpendicular to the target discharge surface. In this case, a strong vertical magnetic field is formed on the target discharge surface, while a horizontal magnetic field is difficult to form, making it difficult for the arc spot to move on the target discharge surface. As a result, the arc spot tends to remain in the same position on the target discharge surface, and the heated coating material is more likely to be released as macroparticles.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an arc evaporation source that can suppress the generation of macroparticles that fly toward the workpiece by promoting the movement of the arc spot on the target discharge surface. [Means for solving the problem]

[0006] The present invention provides an arc evaporation source that vaporizes a coating material by arc discharge and supplies the coating material to a workpiece. The arc evaporation source includes a target, an anode, an arc power supply, an electromagnetic coil, and a central magnet. The target includes a target discharge surface that is disposed rearward of and facing the workpiece and receives an arc discharge to eject the coating material forward. The anode is disposed forward of the target and generates the arc discharge. The arc power supply applies a discharge voltage between the target and the anode to generate the arc discharge. The electromagnetic coil is a cylindrical electromagnetic coil that is disposed forward of the target discharge surface and has a center line perpendicular to the target discharge surface. The electromagnetic coil forms a first magnetic field. The first magnetic field includes first magnetic field lines that intersect the target discharge surface and extend in the front-rear direction through a cylindrical space surrounded by the electromagnetic coil. The central magnet is disposed on the center line behind the target discharge surface to form a second magnetic field. The second magnetic field includes second magnetic field lines extending in the front-rear direction in a region sandwiched between the central magnet and the target discharge surface in the front-rear direction, and the central magnet forms the second magnetic field such that a component of the second magnetic field lines parallel to the center line is opposite to a component of the first magnetic field lines parallel to the center line.

[0007] According to this configuration, the first magnetic field of the electromagnetic coil and the second magnetic field of the central magnet form a repulsive magnetic field around the target discharge surface, which forcibly tilts the magnetic field lines passing through the target discharge surface with respect to the center line, allowing a vertical magnetic field and a horizontal magnetic field to coexist stably on the target discharge surface. As a result, the horizontal magnetic field can actively move the arc spot on the target discharge surface, suppressing the generation of macroparticles, and the vertical magnetic field can stably propel the coating material released from the target discharge surface toward the workpiece.

[0008] In the above configuration, it is desirable that the arc evaporation source further includes an outer magnet that is arranged radially outward of the central magnet behind the target discharge surface and that is capable of forming a third magnetic field including third magnetic field lines extending in the front-to-rear direction in a region in front of the outer magnet and behind the target discharge surface, and that the outer magnet forms the third magnetic field such that a component of the third magnetic field lines that is parallel to the center line is oriented in the same direction as a component of the first magnetic field lines that is parallel to the center line.

[0009] According to this configuration, the outer magnet disposed radially outward of the central magnet can generate a third magnetic field including third magnetic field lines oriented in the same direction as the first magnetic field lines of the first magnetic field, thereby attracting the magnetic field lines tilted by the repulsive magnetic field and forming a magnetic field in which the first and third magnetic field lines are connected around the target discharge surface. This prevents the magnetic field around the target discharge surface from becoming unstable due to the generation of the repulsive magnetic field, and prevents a decrease in the magnetic field strength on the target discharge surface.

[0010] In the above configuration, the device further includes at least one duct that is arranged in front of the target discharge surface and radially inward of the electromagnetic coil, has a cylindrical shape centered on the center line, and surrounds a duct internal space that receives the coating forming material discharged from the target discharge surface and allows the coating forming material to pass toward the workpiece, and the at least one duct is made of a conductive magnetic material and includes a magnetic duct that is arranged in front of the electromagnetic coil so as to attract first magnetic field lines radially outward, and it is desirable that the magnetic duct constitutes at least a part of the anode.

[0011] According to this configuration, the magnetic duct can attract the first magnetic field lines radially outward in front of the electromagnetic coil, thereby preferentially directing electrons emitted from the target discharge surface to the magnetic duct, and stably holding the anode in the arc discharge in the magnetic duct.

[0012] In the above configuration, it is preferable that the magnetic duct has an inner diameter smaller than an inner diameter of the electromagnetic coil and includes a magnetic inner peripheral surface surrounding the duct internal space.

[0013] According to this configuration, the magnetic duct has a magnetic inner surface positioned closer to the center line than the electromagnetic coil, thereby being able to attract the first magnetic lines of force that pass through the inside of the electromagnetic coil more strongly radially outward.

[0014] In the above-described configuration, it is preferable that the apparatus further comprises a vacuum chamber that accommodates the workpiece and the target, and that the vacuum chamber is connected to the at least one duct so as to be insulated from the at least one duct.

[0015] According to this configuration, the duct, which is insulated from the vacuum chamber, functions as an anode, so that the discharge current does not flow into the vacuum chamber, and the arc discharge can be maintained stably.

[0016] In the above configuration, it is desirable that the vacuum chamber comprises a chamber body having a main body space for accommodating the workpiece, and a cylindrical chamber section connected to the chamber body, extending cylindrically around the center line, communicating with the main body space, and having a cylindrical space for accommodating the target, and that the at least one duct is arranged so as to straddle the cylindrical space of the cylindrical chamber section and the main body space of the chamber body between the target and the workpiece.

[0017] According to this configuration, the cylindrical duct is positioned between the chamber tubular portion and the chamber main body, so that the film-forming material emitted from the target discharge surface can be stably guided toward the workpiece contained in the chamber main body, and the generated macroparticles can be more reliably captured on the inner surface of the duct before they reach the workpiece.

[0018] In the above configuration, it is desirable that the at least one duct further has a main duct made of a conductive non-magnetic material and arranged between the target discharge surface and the magnetic duct in the front-to-rear direction, and that the main duct is connected to the magnetic duct so as to be conductive to each other and constitute a part of the anode.

[0019] According to this configuration, since the main duct functioning as an anode is located closer to the target discharge surface than the magnetic duct, an arc discharge can be generated between the main duct and the target discharge surface when the application of the discharge voltage starts, and it is possible to prevent the initial discharge from becoming unstable. Furthermore, since the main duct and the magnetic duct are electrically connected, it is possible to control the area that serves as the anode in the arc discharge according to the coil current after the discharge starts. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an arc evaporation source that can suppress the generation of macroparticles flying toward a workpiece by promoting the movement of the arc spot on the target discharge surface. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic horizontal cross-sectional view of a film formation apparatus including an arc evaporation source according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional side view of an arc evaporation source according to one embodiment of the present invention. [Figure 3] FIG. 2 is an enlarged cross-sectional side view of an arc evaporation source according to one embodiment of the present invention. [Figure 4] FIG. 10 is a schematic horizontal cross-sectional view of a film forming apparatus including an arc evaporation source according to a modified embodiment of the present invention. [Figure 5] FIG. 3 is a diagram showing a magnetic field distribution around a target in Example 1 of the present invention. [Figure 6] FIG. 10 is a diagram showing a magnetic field distribution around a target in Example 2 of the present invention. [Figure 7]FIG. 10 is a diagram showing a magnetic field distribution around a target in Example 3 of the present invention. [Figure 8] FIG. 10 is a diagram showing a magnetic field distribution around a target in Example 4 of the present invention. [Figure 9] FIG. 10 is a diagram showing a magnetic field distribution around a target in Example 5 of the present invention. [Figure 10] FIG. 10 is a diagram showing a magnetic field distribution around a target in Comparative Example 1 of the present invention. [Figure 11] FIG. 10 is a diagram showing a magnetic field distribution around a target in Comparative Example 2 of the present invention. [Figure 12] FIG. 10 is a diagram showing a magnetic field distribution around a target in Comparative Example 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] A film formation apparatus 1 including an arc evaporation source according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic horizontal cross-sectional view of a film formation apparatus 1 including an arc evaporation source 6 according to this embodiment. FIG. 2 is a side cross-sectional view of the arc evaporation source 6 according to this embodiment, taken along a vertical and front-rear direction including a center line CL. FIG. 3 is an enlarged side cross-sectional view of the arc evaporation source 6 according to this embodiment, depicting only a portion below the center line CL. Note that the directions shown in each figure are intended to explain the structure and function of the arc evaporation source 6 and the film formation apparatus 1 according to this embodiment and do not limit the arc evaporation source according to the present invention. That is, the arc evaporation source 6 shown in each figure may be positioned so that its orientation differs in the horizontal and vertical directions. Regarding the front-rear direction in each figure, the direction from the target 7 toward the workpiece 4 is referred to as the front direction, and the opposite direction is referred to as the rear direction. Furthermore, the horizontal direction perpendicular to the front-rear direction and the up-down direction (vertical direction) is referred to as the left-right direction.

[0023] The film forming apparatus 1 forms a film (for example, a nitride film) on a workpiece 4 (substrate) by cathodic arc discharge. Note that the material of the film is not limited to the above. The film forming apparatus 1 has a vacuum chamber 2, a rotary table 3, a plurality of workpieces 4, a vacuum pump 5, and an arc evaporation source 6.

[0024] The vacuum chamber 2 has walls surrounding an internal space, and the internal space is evacuated by a vacuum pump 5. The arc discharge occurs inside the vacuum chamber 2. The internal space contains a turntable 3, multiple workpieces 4, a target 7, and the like. The vacuum chamber 2 is made of a conductive metal material, and in this embodiment, is made of SUS (stainless steel). The vacuum chamber 2 has a chamber main body 2R that has a roughly rectangular parallelepiped shape and a main body space that contains the workpieces 4, and a chamber cylindrical portion 2S (chamber cylindrical portion) that has a cylindrical space that communicates with the main body space of the chamber main body 2R.

[0025] The cylindrical chamber portion 2S accommodates at least the target 7, is connected to the chamber main body 2R so as to extend cylindrically about the center line CL (FIG. 2), and accommodates the target 7 in the cylindrical space. The cylindrical chamber portion 2S may be detachable from the chamber main body 2R. The shape of the cylindrical chamber portion 2S is not limited to the cylindrical shape described above.

[0026] The turntable 3 is disposed within the chamber body 2R of the vacuum chamber 2. The turntable 3 has an upper surface on which multiple workpieces 4 can be placed, and is rotated by a drive mechanism (not shown) about a rotation axis extending in the vertical direction, as indicated by the arrow in FIG. 1. In this embodiment, as shown in FIG. 1, multiple workpieces 4 are disposed on the upper surface of the turntable 3 at predetermined intervals along the rotation direction. As an example, each workpiece 4 includes a rotating jig that can rotate about a rotation axis extending in the vertical direction, and multiple drill bits mounted on the rotating jig.

[0027] The arc evaporation source 6 evaporates the film-forming material by arc discharge and supplies the film-forming material to the workpiece 4. The arc evaporation source 6 has a target 7 containing the film-forming material, a back plate 7H, an anode for generating arc discharge, an electromagnetic coil 8, an arc power supply PS, ducts 9 (main duct 10, tip duct 11, magnetic body 12, introduction duct 13), a yoke plate 14, a central magnet 20, and an outer magnet 30. The film-forming material of the target 7 may be a material whose main ingredient is metal or a material whose main ingredient is carbon, and is not particularly limited.

[0028] The target 7 is disposed behind the workpiece 4 facing the workpiece 4, and includes a target discharge surface 7S (FIG. 3) that receives the arc discharge and emits the coating formation material forward. In this embodiment, the target 7 has a thin cylindrical shape, and the target discharge surface 7S corresponds to the front end surface of the target 7. The target discharge surface 7S has a circular shape with a center line CL extending in the front-to-rear direction. In FIGS. 2 and 3, the direction in which metal ions serving as the coating formation material are supplied toward the workpiece 4 is indicated by an arrow DS.

[0029] The back plate 7H is a cylindrical member that supports the target 7 from behind. The back plate 7H is made of a conductor and is electrically connected to the target 7.

[0030] The electromagnetic coil 8 is disposed in front of the target discharge surface 7S and is a cylindrical electromagnetic coil having a center line CL that is perpendicular to the target discharge surface 7S. Specifically, the electromagnetic coil 8 is configured by winding a coil wire (not shown) multiple times around the center line CL. By receiving a current from a power source (not shown), the electromagnetic coil 8 can form a first magnetic field that includes first magnetic lines of force that intersect with the target discharge surface 7S and extend in the front-rear direction through a cylindrical space surrounded by the electromagnetic coil 8. The first magnetic field will be described in detail below.

[0031] The arc power supply PS includes a negative electrode connected to the target 7 and a positive electrode connected to the anode, and applies a discharge voltage for generating an arc discharge between the target 7 and the tip duct 11, etc. As a result, the target 7 functions as a cathode in the arc discharge.

[0032] The duct 9 is disposed in front of the target discharge surface 7S and radially inward of the electromagnetic coil 8, and has a cylindrical shape centered on the center line CL. The duct 9 includes a main duct 10, a tip duct 11, a magnetic body 12 (magnetic duct), and an introduction duct 13. The duct 9 also has a cylindrical internal space that receives the coating formation material discharged from the target discharge surface 7S and allows the coating formation material to pass toward the workpiece 4. As shown in FIG. 2, the duct 9 is disposed between the target 7 and the workpiece 4, spanning the cylindrical space of the chamber cylindrical portion 2S and the main body space of the chamber main body 2R.

[0033] The main duct 10 is made of a conductive non-magnetic material and is positioned in front of the target discharge surface 7S and radially inside the electromagnetic coil 8. It has a cylindrical shape centered on the center line CL. The main duct 10 has an outer circumferential surface spaced radially from the inner circumferential surface of the electromagnetic coil 8. The main duct 10 is positioned so that its center in the front-to-rear direction faces the electromagnetic coil 8 in the radial direction, and the length of the main duct 10 in the front-to-rear direction is longer than the length of the electromagnetic coil 8. In other words, the electromagnetic coil 8 is positioned radially outside the main duct 10. The inner diameter of the main duct 10 is slightly larger than the outer diameter of the target 7. The main duct 10 is electrically connected to the magnetic body 12 and constitutes part of the anode. For example, the main duct 10 is made of stainless steel. The main duct 10 is insulated from the vacuum chamber 2.

[0034] The tip duct 11 is disposed in front of the main duct 10 and is electrically connected to the main duct 10. The tip duct 11 has a cylindrical shape centered on the center line CL, and the inner peripheral surface of the tip duct 11 is continuous with the inner peripheral surface of the main duct 10. In this embodiment, the inner peripheral surfaces are flush with each other, but this is not limiting. The inner diameter of the tip duct 11 may be larger than the inner diameter of the main duct 10. The outer peripheral surface of the tip duct 11 supports a magnetic body 12. As an example, the tip duct 11 is made of stainless steel. As described above, the positive pole of the arc power supply PS is connected to the tip duct 11 (FIG. 1). The tip duct 11 is insulated from the vacuum chamber 2.

[0035] The magnetic body 12 is made of a conductive magnetic material and is positioned in front of the electromagnetic coil 8, i.e., closer to the workpiece 4 than the electromagnetic coil 8. It has a cylindrical shape centered on the center line CL. As described above, the magnetic body 12 is supported (fixed) on the outer circumferential surface of the tip duct 11. In this embodiment, the magnetic body 12 is made of iron. To be conductive, the magnetic body 12 is preferably a metallic magnetic body other than an insulating magnetic material such as ferrite. The magnetic body 12 is electrically connected to the tip duct 11 and constitutes a part of the anode. The magnetic body 12 is positioned radially inward of the electromagnetic coil 8 when viewed in a direction parallel to the center line CL and has a magnetic inner circumferential surface 12A ( FIG. 2 ) that surrounds the duct internal space. That is, the magnetic body 12 includes a magnetic inner circumferential surface that has an inner diameter smaller than the inner diameter of the electromagnetic coil 8 and surrounds the duct internal space. The inner diameter of this magnetic inner circumferential surface 12A is set larger than the outer diameter of the target discharge surface 7S. 2, the magnetic body 12 is disposed inside the chamber main body 2R. The magnetic body 12 has a function of attracting the magnetic field (magnetic lines of force) formed by the electromagnetic coil 8 by its magnetic properties. In other words, the magnetic lines of force formed by the electromagnetic coil 8 curve radially outward in front of the electromagnetic coil 8 so as to pass through (cross) the magnetic body 12.

[0036] The introduction duct 13 is disposed between the target discharge surface 7S and the main duct 10 in the front-rear direction and has a cylindrical shape centered on the center line CL. The introduction duct 13 introduces the coating formation material discharged from the target discharge surface 7S into the main duct 10. In this embodiment, as shown in FIG. 2 , the introduction duct 13 has a two-stage structure with different outer diameters. The inner and outer diameters of the front section of the introduction duct 13 are set smaller than the inner and outer diameters of the rear section of the introduction duct 13. Furthermore, the front end of the introduction duct 13 is positioned to enter the main duct 10. The inner diameter of the rear end of the introduction duct 13 is set larger than the outer diameter of the target discharge surface 7S. This allows metal ions discharged from the target discharge surface 7S to reliably enter the main duct 10. Note that the introduction duct 13 may have the same inner and outer diameters along the front-rear direction (axial direction). The introduction duct 13 is electrically insulated from the target 7, the main duct 10, and the tip duct 11. As an example, the introduction duct 13 is made of SUS, but may also be made of an insulating material.

[0037] The yoke plate 14 is arranged at a distance behind the target 7 and has a disk shape centered on the center line CL. A central magnet 20 and an outer magnet 30 are fixed to the front surface of the yoke plate 14.

[0038] The central magnet 20 is disposed on the center line CL behind the target discharge surface 7S (target 7). The central magnet 20 is a cylindrical permanent magnet, and in this embodiment, as shown in FIGS. 2 and 3, the south pole is disposed in the front portion of the central magnet 20, and the north pole is disposed in the rear portion of the central magnet 20. The central magnet 20 is capable of forming a second magnetic field including second magnetic field lines extending in the front-to-rear direction in the region sandwiched between the central magnet 20 and the target discharge surface 7S from the front and rear. This second magnetic field will also be described in detail below.

[0039] The outer magnet 30 is arranged in a ring shape around the center line CL radially outside the central magnet 20 so as to surround the central magnet 20 behind the target discharge surface 7S. In this embodiment, multiple permanent magnets are arranged in a ring shape with a gap between them around the center line CL. Each permanent magnet has a cylindrical shape. In this embodiment, as shown in FIGS. 2 and 3 , the north pole is arranged in the front portion of the outer magnet 30 and the south pole is arranged in the rear portion of the outer magnet 30. Note that the outer magnet 30 may be a ring-shaped permanent magnet centered on the center line CL, or may be a ring-shaped magnetic body magnetized with multiple magnetic poles. However, arranging multiple permanent magnets in a ring shape as described above reduces the cost of the arc evaporation source 6. The outer magnet 30 forms a closed magnetic field with the central magnet 20. In particular, the outer magnet 30 can form a third magnetic field including third magnetic field lines extending in the front-rear direction in the region in front of the outer magnet 30 and behind the target discharge surface 7S. Note that this third magnetic field will be described in detail later.

[0040] The yoke plate 14, the central magnet 20, and the outer magnet 30 constitute a magnet unit in the arc evaporation source 6. In this embodiment, as shown in FIG. 2, the central magnet 20 and the outer magnet 30 supported by the yoke plate 14 are disposed outside the cylindrical chamber 2S under atmospheric pressure. However, these magnets (magnetic members) may be disposed inside the cylindrical chamber 2S (vacuum chamber 2). In FIG. 2, the distance between the central magnet 20 and the outer magnet 30 and the target discharge surface 7S is indicated by L1, with the rear surface of the yoke plate 14 as the reference point. Furthermore, the yoke plate 14 is movable by a stroke L2 using a drive mechanism (not shown). As a result, the central magnet 20 and the outer magnet 30 can be moved rearward in response to wear on the surface of the target discharge surface 7S, maintaining a stable magnetic field.

[0041] <About film formation processing using arc discharge> In FIG. 2, when the internal space of the vacuum chamber 2 is evacuated by the vacuum pump 5 and a predetermined coil current flows through the electromagnetic coil 8, the arc power supply PS applies a discharge voltage between the main duct 10, the tip duct 11, and the magnetic body 12 and the target 7, and the target 7 functions as a cathode, and the main duct 10, the tip duct 11, and the magnetic body 12 function as anodes, causing an arc discharge.

[0042] In this embodiment, the magnetic field lines (first magnetic field lines) constituting the magnetic field (first magnetic field) formed by the electromagnetic coil 8 in front of the target discharge surface 7S have a component facing forward. On the other hand, the magnetic field lines (second magnetic field lines) constituting the magnetic field (second magnetic field) formed by the central magnet 20 disposed behind the target 7 on and around the target discharge surface 7S have a component facing backward. That is, the magnetic fields formed by the electromagnetic coil 8 and the central magnet 20 form a repulsive magnetic field between them, so the magnetic field lines passing through the target discharge surface 7S intersect the target discharge surface 7S at an acute angle, as indicated by arrow D1 in FIG. 3 . Therefore, on the target discharge surface 7S, a magnetic field component parallel to the target discharge surface 7S (horizontal magnetic field) and a magnetic field component perpendicular to the target discharge surface 7S (vertical magnetic field) coexist stably. In this case, the components parallel to the center line CL of each magnetic field line formed on the target discharge surface 7S are oriented in the same direction (all forward-facing in FIGS. 2 and 3 ). In reality, the distribution shown in FIG. 3 is rotated around the center line CL.

[0043] As described above, the stable formation of a horizontal magnetic field on the target discharge surface 7S increases the movement speed of the arc spot and prevents the arc spot from remaining in the same place. As a result, a portion of the target discharge surface 7S is locally heated, suppressing the generation of droplets and macroparticles and reducing their size. As a result, large or numerous macroparticles are less likely to reach the workpiece 4, improving the surface roughness of the coating on the workpiece 4.

[0044] Meanwhile, electrons emitted from the target discharge surface 7S of the target 7 due to the arc discharge are subjected to the above-mentioned vertical magnetic field and fly from the target discharge surface 7S toward the workpiece 4 (FIG. 1). Many of these electrons then change direction radially outward, as indicated by arrow D2 in FIG. 3, and preferentially reach the magnetic body 12. As a result, an anode in the arc discharge is stably formed and maintained on the magnetic body 12. Therefore, the position and size of the anode in the arc discharge are less likely to fluctuate, and an increase in the discharge voltage in the arc discharge can be suppressed. As mentioned above, since the main duct 10 and the tip duct 11 also function as anodes in the arc discharge, some of the electrons also reach these components. However, since the magnetic body 12 attracts the magnetic field generated by the electromagnetic coil 8, the anode can be formed exclusively on the magnetic body 12.

[0045] On the other hand, the metal ions (cations) emitted from the target discharge surface 7S have a mass several thousand times greater than that of the electrons, and therefore cannot follow the electrons or the magnetic field lines, and instead proceed radially inward of the magnetic body 12 as indicated by the arrow DS toward the workpiece 4, where they are deposited on the workpiece 4. Therefore, even if the electrons are attracted by the magnetic body 12 as described above to stabilize the arc discharge, it is possible to prevent a decrease in the film formation rate of the carbon ions on the workpiece 4, i.e., a decrease in the productivity of the film formation process.

[0046] As described above, in this embodiment, a repulsive magnetic field is formed around the target discharge surface 7S by the first magnetic field of the electromagnetic coil 8 and the second magnetic field of the central magnet 20, and this repulsive magnetic field can forcibly tilt the magnetic field lines passing through the target discharge surface 7S with respect to the center line CL, allowing a vertical magnetic field and a horizontal magnetic field to coexist stably on the target discharge surface 7S. As a result, the horizontal magnetic field can actively move the arc spot on the target discharge surface 7S, suppressing the generation of macroparticles and reducing their number and size, and the vertical magnetic field can stably propel metal ions (coating material) released from the target discharge surface 7S toward the workpiece 4.

[0047] Furthermore, in this embodiment, the outer magnets 30, which have opposite polarity, are arranged around the central magnet 20, preventing a decrease in the magnetic field strength on the target discharge surface 7S due to the formation of the repulsive magnetic field described above, and the outer magnets 30 can compensate for this magnetic field strength. In particular, the outer magnets 30, which are arranged radially outward of the central magnet 20, can generate a third magnetic field including third magnetic field lines oriented in the same direction as the first magnetic field lines of the first magnetic field. Therefore, a magnetic field is formed outside the repulsive magnetic field as viewed from the center line CL, connecting the first and third magnetic field lines across the target discharge surface 7S. This makes it possible to attract the magnetic field lines tilted by the repulsive magnetic field to the outer magnets 30, preventing the distribution of magnetic field lines (magnetic field) around the target discharge surface 7S from becoming unstable and preventing a decrease in the magnetic field strength on the target discharge surface 7S.

[0048] Furthermore, in this embodiment, the magnetic body 12 can attract some of the first magnetic lines of force radially outward in front of the electromagnetic coil 8, so that electrons emitted from the target discharge surface 7S are preferentially guided to the magnetic body 12, and the anode in the arc discharge can be stably held by the magnetic body 12. As a result, metal ions can be stably emitted from the target discharge surface 7S and stably supplied to the workpiece 4.

[0049] In particular, when viewed along the center line CL, the magnetic body 12 has a magnetic inner peripheral surface 12A (inner peripheral surface) that is positioned radially inward of the electromagnetic coil 8. Therefore, the magnetic field lines (first magnetic field lines) that pass through the inside of the electromagnetic coil 8 can be more strongly attracted radially outward at a position close to the center line CL.

[0050] Furthermore, in this embodiment, the tip duct 11, which is insulated from the vacuum chamber 2, functions as an anode, so that the discharge current does not flow into the vacuum chamber 2, and the arc discharge can be maintained stably. In particular, by using the tip duct 11 as the anode, the discharge space can be limited. As a result, the behavior of the arc discharge is less susceptible to the state inside the chamber (contamination on the chamber inner wall and the arrangement of parts), and stable film formation processing can be performed with high reproducibility.

[0051] Furthermore, in the region between the target 7 and the magnetic body 12, a main duct 10 and a tip duct 11 of the duct 9 are arranged so as to surround the passage area of ​​the metal ions. This makes it possible to collect the macroparticles emitted by the target 7 as shown by the arrow D3, and to prevent the macroparticles from reaching the workpiece 4.

[0052] In particular, the cylindrical duct 9 is positioned so as to straddle the chamber tubular portion 2S and the chamber main body 2R, so that metal ions emitted from the target discharge surface 7S can be stably guided toward the workpiece 4 contained in the chamber main body 2R, and the generated macroparticles can be more reliably collected on the inner surface of the duct 9 before they reach the workpiece 4.

[0053] In this embodiment, the main duct 10 is electrically connected to the magnetic body 12 and constitutes a part of the anode. By locating the main duct 10, which functions as the anode, closer to the target discharge surface 7S than the magnetic body 12, an arc discharge can be generated between the main duct 10 and the target discharge surface 7S when the application of the discharge voltage begins, preventing the initial discharge from becoming unstable. Furthermore, since the main duct 10 and the magnetic body 12 are electrically connected, the anode in the arc discharge can be controlled within the range from the main duct 10 to the magnetic body 12 after the discharge begins. The position and range of the anode also change depending on the coil current (magnetic field strength).

[0054] Furthermore, in this embodiment, an introduction duct 13 is disposed between the target 7 and the main duct 10, and the introduction duct 13 is electrically insulated (floating) from the target 7 and the main duct 10. As a result, discharge can occur at a certain distance between the cathode and the main duct 10, and this insulating distance can suppress the occurrence of abnormal discharge.

[0055] Furthermore, in this embodiment, the main duct 10 and the tip duct 11, which are positioned closer to the target discharge surface 7S than the magnetic body 12, also function as anodes. This facilitates the initiation of arc discharge between the target discharge surface 7S and the main duct 10 and tip duct 11. As the discharge stabilizes, the magnetic body 12 located further forward (downstream) can function as the preferred anode. In this manner, the main duct 10, tip duct 11, and magnetic body 12 are sequentially positioned in front of the target discharge surface 7S, sandwiching the insulated lead-in duct 13 therebetween. This allows the arc discharge to be stably maintained and metal ions to be stably delivered to the workpiece 4. As mentioned above, the position and range of the anode also change depending on the coil current (magnetic field strength).

[0056] The arc evaporation source 6 and the film forming apparatus 1 including the same according to each embodiment of the present invention have been described above. Such an arc evaporation source 6 promotes the movement of the arc spot on the target discharge surface 7S, thereby suppressing the generation of macroparticles flying toward the workpiece 4 and reducing their number and size. However, the present invention is not limited to these embodiments. The following modified embodiments are possible for the arc evaporation source 6 according to the present invention.

[0057] (1) In the above embodiment, the vacuum chamber 2 has been described as having a cylindrical chamber portion 2S, but the present invention is not limited to this. The vacuum chamber 2 may be box-shaped and contain everything from the target 7 to the workpiece 4, or may further contain the central magnet 20 and the outer magnet 30.

[0058] (2) Furthermore, in the above embodiment, a plurality of workpieces 4 are placed on the turntable 3, and the turntable 3 is rotated. However, the workpieces and their arrangement according to the present invention are not limited to this, and may be placed in the vacuum chamber 2 in other ways. Furthermore, the shapes of the workpieces 4, the target 7, etc. are not limited to the above. In particular, the target discharge surface 7S of the target 7 may have a rectangular, polygonal, or other shape that is perpendicular to the center line CL.

[0059] (3) Furthermore, the structure and number of the duct 9 are not limited to the above embodiment. Furthermore, the chamber cylindrical portion 2S of the vacuum chamber 2 may function as the main duct 10. In this case, the arc evaporation source 6 may not have the duct 9.

[0060] (4) Furthermore, the structure of the anode of the arc evaporation source according to the present invention is not limited to the above embodiment. Instead of the duct 9, another anode may be provided in front of the target discharge surface 7S. Also, the main duct 10 may not function as part of the anode.

[0061] (5) In the above embodiment, the magnetic field lines (first magnetic field lines) formed by the electromagnetic coil 8 around the center line CL extend forward, while the magnetic field lines (second magnetic field lines) formed by the central magnet 20 around the target discharge surface 7S extend backward. However, these directions may be reversed. However, it is preferable to set the direction of each magnetic field line as in the previous embodiment. Furthermore, the north and south poles of the magnets may be opposite to each other.

[0062] (6) The arc evaporation source 6 may have only the central magnet 20 without the outer magnet 30. The arc evaporation source 6 may also have no magnetic body 12. In this case, too, the action of the magnetic fields formed by the electromagnetic coil 8 and the central magnet 20 can promote the movement of the arc spot on the target discharge surface 7S.

[0063] (7) In the above embodiment, a single arc evaporation source 6 is provided in the vacuum chamber 2. However, multiple arc evaporation sources 6 may be arranged side by side. By providing multiple chamber cylindrical sections 2S and arc evaporation sources 6 above and below the chamber body 2R as shown in FIG. 2, the film formation process on the workpiece 4 can be facilitated. By arranging the magnetic body 12 of each arc evaporation source 6 so that it extends from the chamber cylindrical section 2S into the chamber body 2R (so that it protrudes into the chamber body 2R), the magnetic fields of adjacent arc evaporation sources 6 are prevented from interfering with each other. As a result, the trajectories of metal ions emitted from the targets 7 of each arc evaporation source 6 can be prevented from being disturbed.

[0064] (8) FIG. 4 is a schematic horizontal cross-sectional view of a film formation apparatus 1 including an arc evaporation source 6 according to a modified embodiment of the present invention. In the previous embodiment, as shown in FIG. 1, the positive pole of the arc power supply PS is connected to the tip duct 11. However, the positive pole of the arc power supply PS may also be connected to the vacuum chamber 2. By electrically connecting the vacuum chamber 2 and the tip duct 11, an arc discharge occurs between the target 7 and the main duct 10, the tip duct 11, and the magnetic body 12. Furthermore, in this case, the vacuum chamber 2 can receive the discharge current of the arc discharge as part of the anode. This complements the functions of the main duct 10, the tip duct 11, and the magnetic body 12 as an anode, preventing excessive discharge current from flowing through the main duct 10, the tip duct 11, and the magnetic body 12 when the arc discharge becomes unstable, thereby preventing damage to these elements. [Example]

[0065] Next, specific examples of the present invention will be described, but the present invention is not limited to the following examples.

[0066] 5, 6, 7, 8, and 9 are diagrams showing the magnetic field distribution around the target in Example 1, Example 2, Example 3, Example 4, and Example 5 of the present invention, respectively. Fig. 10, 11, and 12 are diagrams showing the magnetic field distribution around the target in Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention, respectively. All of these are simplified visualizations of the magnetic field around the target discharge surface 7S obtained by magnetic field analysis simulation.

[0067] Example 1 In Example 1 shown in Figure 5, a central magnet 20 and an outer magnet 30 are disposed behind the target 7. In this case, the central magnet 20 constitutes a north pole, and the outer magnet 30 constitutes a south pole. As described in the above embodiment, a first magnetic field M1 is formed by the electromagnetic coil 8 (Figure 2) at and in front of the target discharge surface 7S, and a second magnetic field M2 is formed by the central magnet behind the target discharge surface 7S. In addition, a third magnetic field M3 is formed by the outer magnet 30 between the target 7 and the outer magnet 30.

[0068] The first magnetic field M1 includes first magnetic field lines Q1 that intersect with the target discharge surface 7S and pass forward through the interior of the duct 9. The components of the first magnetic field lines Q1 that are parallel to the center line CL extend forward. The polarity of the first magnetic field M1 (coil magnetic field) that includes the first magnetic field lines Q1 oriented in this way is referred to as the south pole. Meanwhile, the second magnetic field M2 generated by the central magnet 20 includes second magnetic field lines Q2 that extend backward in the region between the central magnet 20 and the target 7 (the region surrounded by projecting the central magnet 20 onto the target 7 along a direction parallel to the center line CL). That is, the component of the second magnetic field lines Q2 that is parallel to the center line CL is in the opposite direction to the component of the first magnetic field lines Q1 that is parallel to the center line CL. The components of the first magnetic field lines Q1 and the second magnetic field lines Q2 that are parallel to the center line CL are larger than the components that are perpendicular to the center line CL. In reality, the distribution is rotated around the center line CL as shown in Fig. 5. This also applies to the other figures described below.

[0069] As a result, a repulsive magnetic field is formed between the first magnetic field M1 and the second magnetic field M2 as shown in Fig. 5. Therefore, the magnetic field lines near the target discharge surface 7S are inclined so as to be pushed outward in the radial direction, and the horizontal and vertical magnetic fields described above are stably formed on the target discharge surface 7S. The magnetic field lines passing through the target discharge surface 7S are inclined so as to spread outward in the radial direction from the electromagnetic coil 8 (Fig. 2) toward the central magnet 20.

[0070] Furthermore, in the first embodiment, the third magnetic field M3 formed by the outer magnet 30 includes third magnetic field lines Q3 extending forward between the target 7 and the outer magnet 30. That is, the components of the third magnetic field lines Q3 that are parallel to the center line CL are oriented in the same direction as the components of the first magnetic field lines Q1 that are parallel to the center line CL, and are oriented in the opposite direction to the components of the second magnetic field lines Q2 that are parallel to the center line CL.

[0071] In this case, as described above, the magnetic field lines pushed radially outward around the target discharge surface 7S can extend to connect to the outer magnet 30, thereby increasing the stability of the magnetic field radially outward from the target discharge surface 7S.

[0072] In the present invention represented by Example 1, as shown in Fig. 5, the closed magnetic field extending to connect the central magnet 20 and the outer magnet 30 remains behind the target discharge surface 7S and does not reach the target discharge surface 7S. In other words, unlike known magnetron technology, the directions of the magnetic field lines formed on the target discharge surface 7S do not reverse in the forward and backward directions. This prevents significant restriction of the arc spot on the target discharge surface 7S and promotes uneven wear of the target discharge surface 7S, enabling stable discharge and emission of cations (film-forming material).

[0073] <Example 2> 6, a central magnet 20 with an N pole is arranged behind the target 7, but an outer magnet 30 like that in Example 1 is not arranged. In this case, a first magnetic field M1 (coil magnetic field) with an S pole is formed by the electromagnetic coil 8 (FIG. 2) at and in front of the target discharge surface 7S, and a second magnetic field M2 is formed by the central magnet behind the target discharge surface 7S.

[0074] As in the first embodiment, the component of the second magnetic field lines Q2 that is parallel to the center line CL is directed in the opposite direction to the component of the first magnetic field lines Q1 that is parallel to the center line CL. As a result, a repulsive magnetic field is formed between the first magnetic field M1 and the second magnetic field M2, as shown in Fig. 6. Therefore, the magnetic field lines in the vicinity of the target discharge surface 7S are inclined so as to be pushed outward in the radial direction, and the horizontal magnetic field and vertical magnetic field as described above are stably formed on the target discharge surface 7S.

[0075] <Examples 3 and 4> In Example 3 shown in FIG. 7, the outer magnet 30 is shifted 10 mm radially inward compared to Example 1. Similarly, in Example 4 shown in FIG. 8, the outer magnet 30 is shifted 20 mm radially inward compared to Example 1. Similarly, the central magnet 20 constitutes a north pole, and the outer magnet 30 constitutes a south pole. Note that in Example 1, the radially outer side surface of the target 7 and the radially inner side surface of the outer magnet 30 are arranged on the same straight line parallel to the center line CL. Even when the outer magnet 30 is positioned radially inward relative to the radially outer side surface of the target 7, as in Examples 3 and 4, a repulsive magnetic field can be formed in the center of the target discharge surface 7S, and the magnetic field lines passing through the target discharge surface 7S can be set to intersect with the target discharge surface 7S at an acute angle. As a result, the horizontal and vertical magnetic fields described above are stably formed on the target discharge surface 7S.

[0076] <Example 5> In Example 5 shown in Figure 9, the outer magnet 30 is shifted 10 mm radially outward compared to Example 1. In this way, even when the outer magnet 30 is positioned radially outward from the radially outer side surface of the target 7, a repulsive magnetic field can be formed in the center of the target discharge surface 7S, and the magnetic field lines passing through the target discharge surface 7S can be set to intersect with the target discharge surface 7S at an acute angle. As a result, the horizontal and vertical magnetic fields described above are stably formed above the target discharge surface 7S.

[0077] In Examples 3, 4, and 5, the generation of horizontal and vertical magnetic fields similar to those described above was confirmed even when the outer magnet 30 was not provided. In this case, to promote the movement of the arc spot and stably propel the charged particles emitted from the target discharge surface 7S toward the workpiece 4, it is desirable to set the lower limit of the radially inner side surface of the outer magnet 30 to a position 20 mm radially inward from the radially outer side surface of the target 7 and the upper limit to a position 20 mm radially outward from the radially outer side surface of the target 7. It is even more desirable to set the lower limit of the radially inner side surface of the outer magnet 30 to the same radial position as the radially outer side surface of the target 7 and the upper limit to a position 20 mm radially outward from the radially outer side surface of the target 7. If the above range is exceeded, the horizontal magnetic field component on the target discharge surface 7S will be weaker, which may result in relatively weaker performance depending on the arc discharge conditions.

[0078] <Comparative Example 1> Comparative Example 1 shown in Fig. 10 differs from Example 1 in that it does not have the central magnet 20 and the outer magnet 30. In this case, as shown in Fig. 10, first magnetic field lines Q1 containing only vertical components are formed on the target discharge surface 7S, which makes it impossible to promote the movement of the arc spot and results in significant generation of macroparticles.

[0079] <Comparative Example 2> 11 differs from Example 1 in that it does not have the outer magnet 30 and furthermore, the first magnetic field lines Q1 of the electromagnetic coil 8 and the second magnetic field lines Q2 of the central magnet 20 have components in the same direction (forward). In this case as well, as shown in FIG. 11, the first magnetic field lines Q1 that include only vertical components are formed on the target discharge surface 7S, so that the movement of the arc spot cannot be promoted and the generation of macroparticles becomes significant.

[0080] <Comparative Example 3> 12 differs from Example 1 in that, although it has both the central magnet 20 and the outer magnet 30, the first magnetic field lines Q1 and the second magnetic field lines Q2 have components in the same direction (forward) as in Example 2. In this case, as shown in FIG. 12, although slight magnetic field lines that intersect with the target discharge surface 7S at an acute angle are formed on the target discharge surface 7S, no repulsive magnetic field is formed in the center of the target discharge surface 7S, and therefore movement of the arc spot cannot be promoted, making it more difficult to suppress the number and size of macroparticles than in the previous Examples. [Explanation of symbols]

[0081] 1 Film deposition equipment 2. Vacuum chamber 2R chamber body 2S Chamber cylinder 3 Rotating table 4 Work 5. Vacuum pump 6 Arc evaporation source 7. Target 7H Back Plate 7S target discharge surface 8. Electromagnetic Coil 9 Ducts (at least one duct) 10 Main Duct 11 Tip duct 12 Magnetic material (magnetic duct) 13 Inlet duct 14 yoke board 20 Central magnet 30 outer magnet CL center line PS Arc Power Supply

Claims

1. An arc evaporation source that vaporizes a film-forming material by arc discharge and supplies the film-forming material to a workpiece, a target disposed behind the workpiece and facing the workpiece, the target including a target discharge surface that receives an arc discharge and emits the coating forming material forward; an anode disposed in front of the target for generating the arc discharge; an arc power supply that applies a discharge voltage between the target and the anode to generate the arc discharge; a cylindrical electromagnetic coil having a center line perpendicular to the target discharge surface and disposed in front of the target discharge surface so as to form a first magnetic field including first magnetic field lines, the first magnetic field lines intersecting the target discharge surface and extending in a forward-backward direction through a cylindrical space surrounded by the electromagnetic coil; a central magnet disposed on the center line behind the target discharge surface so as to form a second magnetic field including second magnetic field lines, the second magnetic field lines being magnetic field lines extending in a front-to-rear direction in a region sandwiched between the central magnet and the target discharge surface; at least one duct having a cylindrical shape centered on the center line, disposed in front of the target discharge surface and radially inside the electromagnetic coil, the at least one duct surrounding a duct internal space that receives the coating formation material discharged from the target discharge surface and allows the coating formation material to pass toward the workpiece; Equipped with the at least one duct is made of a conductive magnetic material and includes a magnetic duct arranged in front of the electromagnetic coil so as to attract the first magnetic field lines radially outward; the magnetic duct constitutes at least a part of the anode; The central magnet forms the second magnetic field such that a component of the second magnetic field line parallel to the center line is opposite to a component of the first magnetic field line parallel to the center line.

2. an outer magnet arranged radially outward of the central magnet behind the target discharge surface to form a third magnetic field including third magnetic field lines, the third magnetic field lines being magnetic field lines extending in a front-to-rear direction in a region in front of the outer magnet and behind the target discharge surface; The arc evaporation source of claim 1 , wherein the outer magnet forms the third magnetic field such that a component of the third magnetic field line parallel to the center line is oriented in the same direction as a component of the first magnetic field line parallel to the center line.

3. The arc evaporation source according to claim 1 , wherein the magnetic duct includes a magnetic inner peripheral surface that has an inner diameter smaller than an inner diameter of the electromagnetic coil and surrounds the duct internal space.

4. a vacuum chamber that accommodates the workpiece and the target; 4. The arc evaporation source of claim 3, wherein the vacuum chamber is connected to the at least one duct in an insulating manner.

5. The vacuum chamber comprises: a chamber body having a body space for accommodating the workpiece; a chamber cylindrical section connected to the chamber body, extending cylindrically around the center line, communicating with the body space, and having a cylindrical space for accommodating the target; and 5. The arc evaporation source according to claim 4, wherein the at least one duct is arranged between the target and the workpiece so as to straddle the cylindrical space of the chamber cylindrical portion and the main body space of the chamber main body.

6. the at least one duct further includes a main duct made of a conductive non-magnetic material and disposed between the target discharge surface and the electromagnetic coil in the front-rear direction; 6. The arc evaporation source according to claim 4, wherein the main duct is electrically connected to the magnetic duct and constitutes a part of the anode.

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