Cathode unit for magnetron sputtering device and magnetron sputtering device

Abstract

A cathode unit (CU) for a magnetron sputtering device (SM) and a magnetron sputtering device are provided, which can make the target erosion area associated with the sputtering substantially uniform, and can improve the utilization efficiency of the target without causing local disappearance of plasma, etc. A magnet unit (51-54) provided on the side of a target (41-44) facing away from a sputtering surface arranged in a vacuum chamber (1) has a linear central magnet (52) and a peripheral magnet (53) surrounding the central magnet, the peripheral magnet having straight sections (53a, 53b) and a bridging section (53c) bridging the two free ends of the straight sections, so as to generate a magnetic field (Mf) leaking from the sputtering surface in a manner that a line through the position where the vertical component of the magnetic field is zero extends in the long direction of the central magnet and is closed in a racetrack shape, and in a state of maintaining the posture of the peripheral magnet, the two end portions of the central magnet are displaced to the sides of the straight sections of the peripheral magnet different from each other according to the target-side polarity of the central magnet.

Description

TECHNICAL FIELD

[0001] The present application relates to a cathode unit for a magnetron sputtering device and a magnetron sputtering device for forming a prescribed thin film on a substrate to be processed in a magnetron sputtering manner. BACKGROUND

[0002] A magnetron sputtering device generally has a magnet unit on the side opposite to the sputtering surface of a target arranged facing a substrate to be processed in a vacuum chamber. Then, when a rare gas such as argon is introduced into the vacuum chamber in a vacuum atmosphere, and a direct current voltage or an alternating current voltage with a negative potential is applied to the target to sputter the sputtering surface of the target, the ionized electrons in front of the sputtering surface and the secondary electrons generated by sputtering are captured, the electron density is increased, and the plasma density is increased by increasing the collision probability between the electrons and the gas molecules of the rare gas.

[0003] When film formation is performed on a substrate to be processed (hereinafter referred to as "substrate") having a rectangular profile such as a glass substrate, a target having the same profile as the substrate is generally used. The magnet unit generally used at this time has a central magnet having a polarity that changes on the side of the target and a peripheral magnet having straight line portions extending in parallel at equal intervals on both sides of the central magnet and bridging portions bridging both free ends of the straight line portions, and surrounds the central magnet (hereinafter, the direction from the sputtering surface toward the substrate is the direction above the Z-axis direction, and the long side direction of the central magnet is the X-axis direction, and the width direction of the central magnet orthogonal to the X-axis direction is the Y-axis direction). Thus, the magnetic field leaking from the sputtering surface acts in such a manner that the line passing through the position where the perpendicular component of the magnetic field is zero extends in the X-axis direction and closes in a racetrack shape, and a racetrack-shaped plasma is generated in the space between the sputtering surface and the substrate (the space above the sputtering surface). At this time, the electrons in the plasma are bent by the electromagnetic field at both end portions of the X-axis direction of the magnet unit and change the direction, and move along the racetrack in a clockwise or counterclockwise orbiting track according to the magnetism on the upper side of the central magnet and the peripheral magnet.

[0004] Here, it is known that if a prescribed thin film is formed on a substrate using the above-described magnetron sputtering device, the distribution of film thickness and film quality becomes poor in the corner regions of the substrate located on the diagonal. This is considered to be due to the fact that the inertia motion of the electrons in the plasma remains when the electrons are bent by the electromagnetic field and change their orientation, and in particular, the plasma locally expands toward the outside of the Y-axis direction at both ends of the X-axis direction of the magnet unit (i.e., at the corners of the racetrack), resulting in the above. Therefore, in order to make the erosion region of the target uniform in conjunction with the progress of sputtering, if the inertia motion of the above-described electrons is taken into consideration when the magnet unit is caused to reciprocate in the Y-axis direction by a prescribed stroke length, the stroke length has to be set to be short, which in turn makes the non-erosion region large and the utilization efficiency of the target poor. Therefore, a scheme has been proposed in which the intervals of the straight portions of the central magnet and the peripheral magnets are equal, and one of the straight portions and both ends of the central magnet at both ends of the long side direction of the magnet unit are moved to the side of the other straight portion, and the intervals of the central magnet and each straight portion are narrower than the interval of the central region (see, for example, Patent Document 1).

[0005] However, in the case of film formation on a large-area substrate such as a glass substrate used for manufacturing a flat panel display, the target also has to be made long, and as a result, the length of the central magnet or the peripheral magnets of the magnet unit becomes long. In this case, if the magnet unit of the above-described Patent Document 1 is used and the magnet unit is caused to reciprocate in the Y-axis direction and sputter the sputtering surface, it is found that the plasma sometimes becomes unstable in a prescribed length range adjacent to both ends of the long side direction of the magnet unit and inward of the same, or disappears.

[0006] Therefore, the inventors of the present application focused on the trajectory or density of the electrons or secondary electrons (hereinafter referred to as "circulating electrons") in the plasma that circulates along the racetrack, and repeatedly conducted intensive studies, and found the following. That is, an existing magnet unit having straight portions that are equally spaced on both sides of the central magnet and extend in parallel, and two free ends that span across both straight portions, was used as an initial magnet unit, and a magnet unit in which one of the straight portions and both ends of the central magnet are moved to the side of the other straight portion so that the interval of the central magnet and each straight portion is narrower than the interval of the central region, was used as a correction magnet unit, as shown in the above-described Patent Document 1. Further, the region of the racetrack-shaped plasma generated in the space between the sputtering surface and the substrate to be processed, which is close to the central magnet, was taken as the central region, and the region in the opposite direction thereof was taken as the peripheral region. Then, after simulating the density distribution of the circulating electrons in the plasma, it was found that in the initial magnet unit, the density of the circulating electrons in the peripheral region that changes its orientation after being bent by the electromagnetic field locally increases on the XY plane, and the density of the circulating electrons in the peripheral region that changes its orientation after being bent by the electromagnetic field locally decreases. It was thus found that when the trajectory of the circulating electrons in the XZ plane is focused on, the circulating electrons fly toward the substrate to be processed side (the upward direction of the Z-axis) in the central region that has changed its orientation.

[0007] It was confirmed that in the correction magnet unit, in the XY plane, the density of the surrounding electrons in the peripheral region changes little with the change in the orientation, and in the XZ plane, the scattering of the surrounding electrons in the central region toward the substrate side with the change in the orientation is more suppressed (in other words, is captured by the magnetic leakage field) than in the initial magnet unit. On the other hand, it was confirmed that in the XY plane, with the change in the orientation, in a range (a range of a prescribed length from the position at which the interval between the central magnet and each linear portion returns to the same interval as that of the central region) adjacent to each of the end portions of the magnet unit in the long direction and inward of the same, the density of the surrounding electrons in the peripheral region becomes large and expands in the Y-axis direction. It is considered that this results in, for example, the partial disappearance of the plasma when the magnet unit is caused to perform reciprocating motion in the Y-axis direction by a prescribed stroke length. Therefore, it was found that if the scattering of the surrounding electrons in the central region toward the substrate side with the change in the orientation is suppressed and the expansion of the surrounding electrons in the peripheral region with the change in the orientation is suppressed, a racetrack-like plasma in which the electron density distribution is uniform and approximately symmetrical with respect to the X-axis can be generated at the time of sputtering.

[0008] Prior Art Documents

[0009] Patent Documents

[0010]

Patent Document 1

[0011] PROBLEM TO BE SOLVED BY THE INVENTION

[0012] The present invention was completed based on the above insight, and the problem to be solved thereby is to provide a cathode unit for a magnetron sputtering device and a magnetron sputtering device which do not cause, for example, the partial disappearance of the plasma, can make the erosion region of the target accompanying the progress of sputtering substantially uniform, and can improve the utilization efficiency of the target.

[0013] MEANS FOR SOLVING THE PROBLEM

[0014] To solve the above technical problem, the cathode unit for a magnetron sputtering device according to the present application is characterized in that a magnet unit is provided on the side of a target, which is disposed in a vacuum chamber, opposite to a sputtering surface, the magnet unit has a central magnet and a peripheral magnet surrounding the central magnet, the central magnet and the peripheral magnet are arranged on the side of the target with opposite polarities, the peripheral magnet has straight line portions extending in parallel at equal intervals on both sides of the central magnet and bridging portions bridging both free ends of the straight line portions, and the bridging portions are arranged so that a line passing through a position where the perpendicular component of the magnetic field is zero extends in the longitudinal direction of the central magnet and is closed in a racetrack shape to generate a magnetic field leaking from the sputtering surface, and in a state in which the posture of the peripheral magnet is maintained, the both end portions of the central magnet are displaced to the straight line portions of the peripheral magnet on different sides from each other in accordance with the polarity of the target side of the central magnet.

[0015] Thus, if the density distribution of the gyrating electrons in the plasma is simulated, the spread of the gyrating electrons in the peripheral region before and after the change of direction to the Y-axis direction can be suppressed in addition to the suppression of the spread of the gyrating electrons in the central region before and after the change of direction to the side of the substrate to be processed. Thus, when the cathode unit according to the present application is assembled in a magnetron sputtering device and plasma is generated as described above, plasma having a racetrack shape in which the electron density distribution is substantially symmetrical about the X-axis over substantially the entire length of the magnet unit is generated. In this case, the length of the both end portions of the central magnet displaced is set, for example, to one time or more the distance between the straight line portions in accordance with the length of the magnet unit in the X-axis direction, the distance between the sputtering surface and the substrate to be processed, the power applied to the target during sputtering, and the like. At this time, if the both end portions of the central magnet are displaced so that the interval between the straight line portions decreases stepwise toward the both ends of the central magnet, the difference in the density of the gyrating electrons in the peripheral region before and after the change of direction can be further reduced. Alternatively, the central magnet can be fixed and the both end portions of the straight line portions (and the bridging portions) of the peripheral magnet can be displaced in different directions from each other with respect to the central magnet, but in this case, the spread of the gyrating electrons in the peripheral region before and after the change of direction cannot be suppressed.

[0016] Further, in order to solve the above problems, the magnetron sputtering device of the present application is characterized in that: a magnet unit is provided below a target disposed opposite a substrate to be processed in a vacuum chamber; a power source applies power to the target; and a gas introduction device introduces an inert gas into the vacuum chamber; the magnet unit has a central magnet disposed in a linear shape and a peripheral magnet surrounding the central magnet, and the peripheral magnet has straight line portions extending in parallel at equal intervals on both sides of the central magnet and bridging portions bridging both free ends of the straight line portions; a drive device is provided to move the magnet unit back and forth in a prescribed stroke length in at least a Y-axis direction, with a long side direction of the central magnet being the X-axis direction and a direction from the central magnet toward the straight line portions of the peripheral magnet being the Y-axis direction orthogonal to the X-axis direction; and an electron emission suppression device is provided to suppress emission of electrons upward when the electrons change direction at a corner portion of a racetrack-shaped plasma generated above the sputtering surface by introducing the inert gas into the vacuum chamber and then applying power to the target.

[0017] In the present application, the electron emission suppression device is configured by shifting both end portions of the central magnet to different straight line portions of the peripheral magnet according to the polarity of the target side of the central magnet while maintaining the posture of the peripheral magnet. Alternatively, a permanent magnet or an electromagnet can be provided at a position where sputtered particles do not fly in the vacuum chamber or outside the vacuum chamber, and the electrons that are to be emitted upward when changing direction can be captured onto the original track by the magnetic field. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a schematic view of a partial cross section of a magnetron sputtering device having a cathode unit of the present embodiment.

[0019] Figure 2 (a) is a plan view omitting a portion of a magnet unit used in the cathode unit of the present embodiment, Figure 2 (b) is a graph illustrating the density distribution of the circulating electrons in the plasma in the XY plane, Figure 2 (c) is a graph illustrating the density distribution of the circulating electrons in the plasma in the XZ plane.

[0020] Figure 3 (a) is a graph illustrating the density distribution of the circulating electrons in the plasma in the XY plane of the magnet unit of the prior art example, Figure 3 (b) is a graph illustrating the density distribution of the circulating electrons in the plasma in the XZ plane.

[0021] Figure 4(a) is a graph showing the density distribution of the surrounding electrons in the plasma in the XY plane of the magnet unit of the other existing example, Figure 4 (b) is a graph showing the density distribution of the surrounding electrons in the plasma in the XZ plane. DETAILED DESCRIPTION

[0022] Referring to the drawings, an embodiment of a magnetron sputtering apparatus cathode unit and a magnetron sputtering apparatus according to the present application will be described below, taking as an example a so-called multi-target type magnetron sputtering apparatus in which a plurality of targets having a rectangular profile are arranged in parallel at equal intervals in one direction, for use in manufacturing a large-area glass substrate (hereinafter referred to as "substrate Sw") for a flat panel display. Figure 1 The setting posture of the magnetron sputtering apparatus SM of this embodiment is such that the direction from the sputtering surface of the target toward the substrate Sw is the upper side of the Z-axis direction, the long-side direction of the central magnet mentioned later is the X-axis direction, and the width direction of the central magnet orthogonal to the X-axis direction is the Y-axis direction.

[0023] Referring to Figure 1 The magnetron sputtering apparatus SM of this embodiment has a vacuum chamber 1 defining a film formation chamber 11. An exhaust port 12 is formed in the wall surface of the vacuum chamber 1, and an exhaust pipe 13 connected to a vacuum exhaust unit Pu composed of a rotary pump, a dry pump, a turbo molecular pump, or the like is connected to the exhaust port 12, so that the film formation chamber 11 is vacuum-exhausted and maintained at a predetermined pressure (for example, 1 x 10 - 5 Gas supply ports 21a and 21b are also formed in the wall surface of the vacuum chamber 1, and gas pipes 23a and 23b provided with mass flow controllers 22a and 22b, respectively, are connected to the gas supply ports 21a and 21b, so that a rare gas (inert gas) such as argon gas and a reaction gas such as oxygen gas can be introduced into the film formation chamber 11 as needed, and they constitute a gas introduction device of this embodiment.

[0024] A substrate transport device 3 is provided in the upper space in the vacuum chamber 1. The substrate transport device 3 is provided with a carrier 31 that holds a substrate Sw with its lower surface (film formation surface) open, and an external drive source that freely transports the carrier 31 in the Y-axis direction. In addition, the substrate transport device 3 can be configured using known components, and thus detailed description thereof is omitted. Further, a cathode unit CU of the present embodiment is provided in the lower portion of the vacuum chamber 1, and opposes the substrate Sw held on the carrier 31 transported to a prescribed position in the film formation chamber 11. The cathode unit CU is provided with four targets 41 to 44 that are arranged in parallel at equal intervals in the Y-axis direction with their upper surfaces (sputtering surfaces) in the XY plane when not in use, and magnet units 51 to 54 that are respectively arranged in the space below (outside the vacuum chamber) each of the targets 41 to 44. Each of the targets 41 to 44, which are made of the same substantially cuboid shape according to the composition of the film to be formed on the lower surface of the substrate Sw, has a size (length in the X-axis direction and width in the Y-axis direction) that is set so that the outline of each of the targets 41 to 44 is one larger than the substrate Sw when opposing the substrate Sw. Back plates 41 made of copper are respectively joined to the lower surfaces of each of the targets 41 to 44 via a joining material (not shown) such as indium, and are arranged on the bottom surface of the vacuum chamber 1 via an insulator 42 in a state in which each of the targets 41 to 44 can be cooled during sputtering. The targets 41, 42 and 43, 44 that are adjacent to each other are respectively paired, and an output 61 from an alternating current power source 6 as a power source is connected to each pair of targets 41 to 44, and the alternating current power source 6 can apply alternating current power of a prescribed frequency (for example, 1 kHz to 100 kHz) between each pair of targets 41, 42 and 43, 44. In addition, depending on the type of the targets, direct current power with a negative potential can be applied to each of the targets 41 to 44.

[0025] Also with reference to Figure 2, each of the magnetic units 51 to 54 has a support plate 51 (magnetic yoke) which is parallel to the back plate 41 and is made of a flat plate of a magnetic material. In the center of the upper surface of the support plate 51, a central magnet 52 and a peripheral magnet 53 are arranged in the X-axis direction in a linear manner with the polarity of the target changed (for example, the central magnet 52 is an S pole and the peripheral magnet 53 is an N pole). The peripheral magnet 53 has straight portions 53a and 53b which are parallel and equally spaced on both sides of the central magnet 52, and bridging portions 53c which bridge the two free ends of the straight portions 53a and 53b. In this case, the central magnet 52 and the peripheral magnet 53 are integrally made of a neodymium magnet or the like, or are made of magnet pieces of a neodymium magnet or the like arranged in a row, and the central magnet 52 and the peripheral magnet 53 are designed to have the same volume when magnetized. Thus, in the space in the film forming chamber 11 between the upper surfaces (sputtering surfaces) of the targets 41 to 44 and the lower surface of the substrate Sw, a magnetic field Mf which leaks from the sputtering surfaces and which extends in the X-axis direction in a linear manner through a position where the perpendicular component of the magnetic field is zero and which is closed in a racetrack shape is generated. Further, nut members 54 are provided on the lower surfaces of the support plates 51 of the magnetic units 51 to 54, and feed screws Fs which are connected to the motor Mt are screwed to the nut members 54. During sputtering, the magnetic units 51 to 54 are moved in the Y-axis direction with a predetermined stroke length in a reciprocating manner, and these constitute a drive device of the present embodiment. Alternatively, the magnetic units 51 to 54 can be moved in the X-axis direction with a predetermined stroke length in a reciprocating manner.

[0026] In the case where the above-described magnetron sputtering device SM is used to form a film on the lower surface of the substrate Sw, the substrate Sw is transported to a predetermined position in the film forming chamber 11 facing the targets 41 to 44 by the substrate transport mechanism 3, and the film forming chamber 11 is vacuumed to a predetermined pressure. When the film forming chamber 11 reaches the predetermined pressure, the flow rate is controlled by the mass flow controllers 22a and 22b and a rare gas (a reaction gas is introduced as necessary) is introduced, and alternating current power is applied between each pair of targets 41 to 44 by the alternating current power source 6. Thus, a racetrack-shaped plasma PL is generated above the sputtering surfaces of the targets 41 to 44. At this time, the electrons in the plasma PL are bent by the electromagnetic field at both ends of the X-axis direction of each magnetic unit 51 to 54 and change the direction, and move along the racetrack in a clockwise or counterclockwise orbit depending on the magnetism on the upper side of the central magnet 52 and the peripheral magnet 53. Then, the ions of the rare gas ionized by the plasma PL sputter the sputtering surfaces, and the sputtered particles flying from the sputtering surfaces in accordance with a predetermined cosine law are deposited on the lower surface of the substrate Sw to form a film. At this time, by moving each magnetic unit 51 to 54 in the Y-axis direction with a predetermined stroke length in a reciprocating manner, each target 41 to 44 is eroded substantially equally in the Y-axis direction.

[0027] Here, as shown in Figure 3 (a), the existing magnet unit having the linear portions 530a, 530b extending in parallel at equal intervals on both sides of the central magnet 520 provided on the support plate 510 and the bridging portion 530c bridging both free ends of the linear portions 530a, 530b, respectively, is taken as the initial magnet unit Mu 1. Further, as shown in Figure 4 (a), the magnet unit having the linear portions 531a, 531b extending in parallel at equal intervals on both sides of the central magnet 521 provided on the support plate 511 and the bridging portion 531c bridging both free ends of the linear portions 531a, 531b, respectively, is taken as a reference, and as shown in the above Patent Document 1, the magnet unit in which the linear portion 531a side and both end portions of the central magnet 521 are moved to the linear portion 531b side on the other side is taken as the correction magnet unit Mu2 in which the interval between the central magnet 521 and each linear portion 531a, 531b is narrower than the interval in the central region. Further, as shown by the dotted line in Figure 1 , the region close to the central magnet 521 in the racetrack-shaped plasma PL generated in the space between the sputtering surface and the substrate Sw is taken as the central region Pc, and the regions in the opposite direction thereof are taken as the peripheral regions Ppl, Pp2. Then, when the orbit and the density distribution of the circulating electrons in the simulated plasma PL are observed, in the initial magnet unit Mu 1, as shown in Figure 3 (a) and 3(b), the density of the circulating electrons in the peripheral region Ppl before the orientation is changed by the electromagnetic field (at both end portions of the initial magnet unit Mu 1) is locally increased, and on the other hand, the density of the circulating electrons in the peripheral region Pp2 after the orientation is changed is locally decreased, in the XY plane. Further, when the orbit of the circulating electrons is observed in the XZ plane, the circulating electrons are scattered upward in the Z-axis direction in the central region Pc after the orientation is changed. Further, in Figures 2 to 4 , the orbit of the circulating electrons is indicated by a thin curve, and the density of the circulating electrons in the orbit is indicated by the hatching.

[0028] In the correction magnet unit Mu2, as shown in Figure 4As shown in (a) and (b), in the XY plane, the density difference of orbiting electrons in the peripheral regions Pp1 and Pp2 before and after the orientation change is not significant. In the XZ plane, the scattering of orbiting electrons in the central region Pc towards the substrate Sw side after the orientation change is more suppressed compared to the initial magnet unit Mu1 (in other words, they are captured by the leakage magnetic field Mf). On the other hand, after the orientation change, in a range Lp of a predetermined length adjacent to the two ends of the long side and towards its inward direction (a range of a predetermined length starting from the position where the interval between the central magnet 521 and each straight section 531a, 531b returns to the position equal to the interval of the central region), the density of orbiting electrons in the peripheral region Pp2 increases and expands in the Y-axis direction. It can be considered that this leads to the local disappearance of plasma when the correction magnet unit Mu2 moves back and forth in the Y-axis direction with a predetermined stroke length.

[0029] In each magnet unit 51 to 54 of this embodiment, as follows: Figure 2 As shown in (a), a structure is adopted in which, while maintaining the orientation of the peripheral magnets 53, the two end portions 52a and 52b of the central magnet 52 are shifted to the sides of the different straight portions 53a and 53b of the peripheral magnets 53, respectively, according to the target-side polarity of the central magnet 52 (in other words, according to the direction of electron circumference). In this case, the length L1 of the two end portions 52a and 52b of the shifted central magnet 52 is appropriately set according to the X-axis length of the magnet units 51 to 54, the distance between the sputtering surface and the substrate Sw, and the power applied to the targets 41 to 44 during sputtering, for example, it is set to more than one times the distance L2 between the two straight portions 53a and 53b. At this time, the two end portions 52a and 52b of the central magnet 52 shift in a stepped manner (stepwise) as they move toward the end of the central magnet, with the interval between them and the straight portions 53a and 53b decreasing in stages. Alternatively, the two end portions 52a and 52b of the central magnet 52 can be shifted by continuously decreasing the interval between them and the straight portions 53a and 53b as they move toward the end of the central magnet (for example, by tilting the two end portions 52a and 52b of the central magnet 52 relative to the X-axis direction).

[0030] It can be confirmed that when the magnet units 51-54 of this embodiment are used to simulate the orbital and density distribution of orbiting electrons in plasma PL, as shown in the figure... Figure 2(b) and (c), the density of the trapped electrons in the peripheral regions Ppl, Pp2 does not change greatly in the XY plane, and the scattering of the trapped electrons in the central region Pc toward the substrate Sw side is further suppressed (in other words, the trapped electrons are captured by the magnetic leakage field Mf) in the XZ plane after the change in the orientation. Also, it is confirmed that the density of the trapped electrons in the peripheral region Pp2 does not spread in the Y-axis direction even after the change in the orientation. Thus, it is understood that the structure in which the both end portions 52a, 52b of the central magnet 52 are displaced toward the different linear portions 53a, 53b of the peripheral magnet 53, respectively, functions as the electron scattering suppressing device that suppresses the scattering of the trapped electrons upward.

[0031] With the present embodiment, the racetrack-shaped plasma PL that is substantially symmetric about the X-axis and has a uniform electron density distribution can be formed over substantially the entire length of the magnet units 51 to 54. Therefore, if a predetermined thin film is formed on the substrate Sw using the magnetron sputtering device SM provided with the above-described magnet units 51 to 54, the film thickness and film quality can be distributed favorably over the entire surface of the substrate Sw, and the utilization efficiency of each target 41 to 44 can be improved by setting the stroke length of the reciprocating movement in the Y-axis direction by the driving devices Mt, Fs to be long. Also, although not particularly illustrated, the central magnet 52 can be fixed and the both end portions (and the bridging portion) of the two linear portions 53a, 53b of the peripheral magnet 53 can be displaced in different directions with respect to the central magnet 52, but it is confirmed that the scattering of the trapped electrons in the peripheral region after the change in the orientation cannot be suppressed by this.

[0032] The above-described embodiments of the present application have been described, but various modifications can be made without departing from the technical scope of the present application. In the above-described embodiments, the electron scattering suppressing device in which the both end portions 52a, 52b of the central magnet 52 are displaced toward the different linear portions 53a, 53b of the peripheral magnet 53, respectively, has been described as an example, but the present application is not limited thereto. The present application can be applied to a magnetron sputtering device in which a single magnet unit is disposed on one target, or a so-called multi-magnet type magnetron sputtering device in which a plurality of magnet units are disposed in parallel at equal intervals with respect to one target.

[0033] Also, in the above-described embodiments, a so-called multi-target type magnetron sputtering device SM in which a plurality of targets 41 to 44 are disposed in parallel at equal intervals has been described as an example, but the present application is not limited thereto. The present application can be applied to a magnetron sputtering device in which a single magnet unit is disposed on one target, or a so-called multi-magnet type magnetron sputtering device in which a plurality of magnet units are disposed in parallel at equal intervals with respect to one target.

[0034] Reference Signs List

[0035] SM. magnetron sputtering device, CU. cathode unit, 1. vacuum chamber, 21a, 21b. gas supply port (constituent element of gas introduction device), 22a, 22b. mass flow controller (constituent element of gas introduction unit), 23a, 23b. gas pipe (constituent element of gas introduction device), 41-44. target, 51-54. magnet unit, 52. central magnet, 52a, 52b. both end portions of central magnet 52 (electron emission suppression device), 53. peripheral magnet, 53a, 53b. straight portion, 53c. crossover portion, Mf. magnetic field, 6. AC power source (power source), Mt. motor (constituent element of driving device), Fs. feed screw (constituent element of driving device), 54. nut member (constituent element of driving device).

Claims

1. A cathode unit for a magnetron sputtering apparatus, provided with a magnet unit arranged on a side of a target, which is arranged in a vacuum chamber, opposite to a sputtering surface of the target, the magnet unit having a central magnet arranged in a linear shape and a peripheral magnet surrounding the central magnet, the peripheral magnet having straight line portions extending in parallel at equal intervals on both sides of the central magnet and bridge portions bridging both free ends of the straight line portions, respectively, to generate a magnetic field leaking from the sputtering surface in a manner that a line through a position where a perpendicular component of the magnetic field is zero extends in a long side direction of the central magnet and is closed in a racetrack shape, characterized in that: in a state where the posture of the peripheral magnet is maintained, in accordance with a target side polarity of the central magnet, both end portions of the central magnet are displaced into the plasma in the straight line portion, on the side where the orientation of the plasma is changed by the bending of the electrons by the electromagnetic field, after the displacement, to the straight line portion different from the other, so that the length of the displaced both end portions of the central magnet is set to be more than one time the distance between the two straight line portions.

2. The cathode unit for a magnetron sputtering apparatus according to claim 1, characterized in that: the both end portions of the central magnet are displaced so that the interval between the straight line portion and the both end portions of the central magnet becomes smaller in steps toward the both ends of the central magnet, and when the plasma in the racetrack shape is generated in a space above the sputtering surface, the density difference in the peripheral region before and after the change in the orientation of the orbiting electrons in the plasma performing a circular motion along the racetrack is reduced.

3. A magnetron sputtering apparatus, provided with: a magnet unit arranged below a target arranged opposite to a substrate to be processed in a vacuum chamber with the sputtering surface side of the target up; a power source applying electric power to the target; and a gas introducing device introducing an inert gas into the vacuum chamber of a vacuum atmosphere; characterized in that: the magnet unit has a central magnet arranged in a linear shape and a peripheral magnet surrounding the central magnet, the peripheral magnet having straight line portions extending in parallel at equal intervals on both sides of the central magnet and bridge portions bridging both free ends of the straight line portions, respectively, and a drive device is provided to make the magnet unit perform a reciprocating motion in a prescribed stroke length in at least a Y axis direction which is a width direction of the central magnet orthogonal to an X axis direction which is a long side direction of the central magnet; an electron emission suppressing device is provided to suppress the emission of the electrons upward when the electrons in the plasma change the direction at the corner portion of the racetrack when the plasma in the racetrack shape is generated in a space above the sputtering surface by introducing the inert gas into the vacuum chamber of the vacuum atmosphere and applying electric power to the target; and in a state where the posture of the peripheral magnet is maintained, in accordance with a target side polarity of the central magnet, both end portions of the central magnet are displaced into the plasma in the straight line portion, on the side where the orientation of the plasma is changed by the bending of the electrons by the electromagnetic field, after the displacement, to the straight line portion different from the other, so that the length of the displaced both end portions of the central magnet is set to be more than one time the distance between the two straight line portions.

4. The magnetron sputtering apparatus according to claim 3, characterized in that: ​ ​ ​ ​ ​ In a state where the posture of the peripheral magnets is maintained, the both end portions of the central magnet are displaced to the straight line portion sides of the peripheral magnets different from each other, respectively, according to the target side polarity of the central magnet, thereby constituting the electron emission suppressing device.

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