Rotary cathode unit and magnetron sputtering apparatus equipped with a rotary cathode unit

Abstract

The present invention provides a rotary cathode unit for a magnetron sputtering apparatus that can significantly reduce damage energy and suppress attenuation of PL intensity. [Solution] The cathode unit comprises a cylindrical target that is longitudinal in one axis direction, a driving means for rotating the cylindrical target around its axis, and a magnet unit 5 assembled inside the cylindrical target that generates a leakage magnetic field such that a line passing through a position where the vertical component of the magnetic field is zero extends along the X axis direction and closes in a racetrack shape. The magnet unit has peripheral portions 52 on both sides in the X axis direction that form the corners of the racetrack, and a central portion 51 located between each peripheral portion. The line passing through the position where the vertical component of the magnetic field is zero in the central portion is spaced further away from the film deposition surface in the Z axis direction compared to the peripheral portions.

Description

Technical Field

[0001] The present invention relates to a rotary cathode unit for a magnetron sputtering apparatus disposed opposite to a film formation surface of an object to be filmed in a vacuum chamber, and a magnetron sputtering apparatus including the rotary cathode unit.

Background Art

[0002] In a top emission type organic EL display device, in order to improve the color purity and the light extraction efficiency by a microcavity structure, a light extraction layer called a capping layer is provided on a cathode electrode layer. Conventionally, such a light extraction layer has been formed by vapor-depositing a layer (thin film) made of an organic material by a vacuum vapor deposition method. However, there are problems such as the high cost of the organic material itself and the enlargement of the vapor deposition equipment. Therefore, the light extraction layer is composed of oxides or nitrides of transition metals (for example, indium oxide, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, zinc oxide, niobium oxide, titanium oxide, tantalum oxide, molybdenum oxide). And it has been proposed to form a layer of an oxide or nitride of a transition metal by a magnetron sputtering apparatus. At this time, for example, how to avoid damaging an already formed underlying layer made of an organic material such as an electron transport layer or a light emitting layer becomes an important issue.

[0003] A magnetron sputtering apparatus of this type is generally known to have a rotary cathode unit inside a vacuum chamber (see, for example, Patent Document 1). In this apparatus, the rotary cathode unit comprises a cylindrical target that is longitudinal in one direction (X-axis direction), a driving means that rotates the cylindrical target around the X-axis, and a magnet unit assembled inside the cylindrical target that generates a magnetic field that leaks from the cylindrical target (into the space between the cylindrical target and the object to be deposited). Multiple such rotary cathode units (for example, two) are arranged side by side with spacing in the Y-axis direction perpendicular to the X-axis direction. Each magnet unit has a central magnet positioned along the X-axis direction on the upper surface of a magnetic material support (yoke) facing the object to be deposited, and peripheral magnets that surround the central magnet at equal intervals, with the polarity on the object side reversed. A magnetic field is generated such that a line passing through the position where the vertical component of the magnetic field is zero extends along the X-axis direction and closes in a racetrack shape.

[0004] Here, whether or not the organic substrate layer has been damaged by the subsequent deposition of transition metal oxides or nitrides can be analyzed using photoluminescence intensity (PL intensity), and it is known that if the substrate layer is damaged, the PL intensity decreases significantly. On the other hand, factors that cause damage to the organic substrate layer include, in particular, the collision of electrons generated by the ionization of sputtered gas in the plasma, positive ions and recoiled particles of the sputtered gas (hereinafter simply referred to as "positive ions") with the deposition surface of the object to be deposited. In other words, these have higher energy than the bond dissociation energy between atoms and molecules of the organic material constituting the substrate layer, and therefore have the potential to damage the substrate layer. Therefore, the inventors of this application defined the damage energy inflicted on the substrate layer during deposition as the product of the flux (number) of positive ions and the kinetic energy of the positive ions, and after diligent research, they found that if the damage energy can be reduced, the decrease in PL intensity can be suppressed. The flux (number) of positive ions is related to the position and density of the plasma generated in the vacuum chamber. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-218604 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention is based on the above findings and aims to provide a rotary cathode unit for a magnetron sputtering apparatus and a magnetron sputtering apparatus equipped with a rotary cathode unit that can significantly reduce damage energy and suppress attenuation of PL intensity compared to the above-mentioned conventional examples. [Means for solving the problem]

[0007] To solve the above problems, the rotary cathode unit for a magnetron sputtering apparatus of the present invention, which is positioned in a vacuum chamber facing the film deposition surface of the object to be deposited, has two orthogonal directions as the X-axis and Y-axis, and a direction perpendicular to the X-axis and Y-axis as the Z-axis, and the cathode unit comprises a cylindrical target that is longitudinal in the X-axis direction, a driving means for rotating the cylindrical target around the X-axis, and a magnet unit assembled inside the cylindrical target that generates a magnetic field that leaks from the cylindrical target such that a line passing through a position where the vertical component of the magnetic field is zero extends along the X-axis and closes in a racetrack shape, and the magnet unit has peripheral portions on both sides in the X-axis direction that form the corners of the racetrack, and a central portion located between the peripheral portions, and is configured such that the line passing through the position where the vertical component of the magnetic field is zero in the central portion is spaced further away from the film deposition surface in the Z-axis direction compared to the peripheral portions. In the present invention, the magnet unit comprises a pair of magnets arranged with different polarities on the film-forming surface side, and preferably the first angle between the position where the vertical component of the magnetic field generated by the pair of magnets extending in the X-axis direction in the central part is zero and the center line in the Z-axis direction passing through the rotation center of the cylindrical target is in the range of 50 to 75 degrees, and the second angle between the position where the vertical component of the magnetic field generated by the pair of magnets in the peripheral part is zero and the Z-axis direction passing through the rotation center of the cylindrical target is in the range of 20 to 70 degrees.

[0008] In the conventional magnetron sputtering apparatus described above, when the object to be deposited is directly facing the cathode unit, the magnet unit is generally designed such that the portion of the magnetic field extending approximately linearly in the X-axis direction of the magnetic field that closes in a racetrack-like manner when the line passing through the position where the vertical component of the magnetic field is zero is equal to the X-axis length of the object to be deposited. In this case, using the damage energy (flux (number) × kinetic energy) applied to the film deposition surface of the object as a reference, in the present invention, it has been confirmed that if the line passing through the position where the vertical component of the magnetic field is zero in the central part is spaced further away from the film deposition surface in the Z-axis direction compared to the peripheral part, the damage energy can be significantly reduced, and the attenuation of PL intensity due to film deposition can be significantly suppressed.

[0009] In this invention, the "central portion" essentially corresponds to the portion of the magnetic field that extends substantially linearly in the X-axis direction within the racetrack-like closing magnetic field, as described above. The X-axis length of the central portion is set so that when the object to be deposited is directly facing the cathode unit, most of it faces the object to be deposited (i.e., this includes not only cases where the X-axis length of the central portion is shorter than the substrate to be processed, but also cases where it is slightly longer than the substrate to be processed). The ratio of the central portion to the X-axis length (total length) of the cathode unit is set in the range of 50% to 95%. If this ratio is less than 50%, the reduction of damage energy will be insufficient, while if it is greater than 95%, the formation of the magnetic field necessary to close in a racetrack shape will be insufficient, and the discharge will tend to become unstable. On the other hand, the ratio of the peripheral portion to the X-axis length (total length) of the cathode unit is set in the range of 5% to 35%. If this ratio is less than 5%, the formation of the racetrack between the central portion and the additional corner portion will be distorted, and the discharge will tend to become unstable, while if it is greater than 35%, the reduction of damage energy will be insufficient. While it is technically possible to reduce damage energy even when the ratio is greater than 35% by designing the central section to be longer, this would lead to an increase in the size of not only the magnet unit and cylindrical target, but also the device itself, which would be disadvantageous in terms of cost and other factors.

[0010] Incidentally, electrons and secondary electrons (hereinafter referred to as "circulating electrons") in the plasma that are moving in a circular motion along the race track are bent and changed direction by the electromagnetic field in the peripheral part of the magnet unit (i.e., the corner part of the race track), and move in a clockwise or counterclockwise circular orbit along the race track depending on the magnetism of the upper part of the pair of magnets. At this time, in a magnet unit like the conventional example described above, the density of circulating electrons is high in the peripheral part before they are bent and changed direction by the electromagnetic field, and the density of circulating electrons is low in the peripheral part after they have changed direction, and it is known that the circulating electrons after they have changed direction scatter toward the object to be deposited (upward in the Z-axis direction). In addition, since the magnetic field lines formed by the magnet unit extend toward the object to be deposited, electrons and positive ions entangled in the magnetic field lines also affect the object to be deposited. Therefore, in the present invention, it is preferable to adopt a configuration in which the second angle decreases continuously or stepwise as it moves outward in the X-axis direction. This reduces the difference in electron density in the peripheral area before and after the orientation change, and also suppresses the scattering of electrons from the orientation change toward the substrate being processed.

[0011] In this invention, in order to further suppress the scattering of circumferential electrons toward the substrate being processed, the magnet unit may further be provided with additional corner portions on both outer sides in the X-axis direction of the peripheral portion. A rod-shaped central magnet extending in the X-axis direction and rod-shaped peripheral magnets spaced apart on both sides of the central magnet in the Y-axis direction are provided in the additional corner portions to generate a closed-loop magnetic field that is balanced between the central magnet and the two peripheral magnets. The ratio of the additional corner portion to the X-axis length (total length) of the cathode unit is set in the range of 1% to 20%. If this ratio is less than 1%, the formation of a magnetic field necessary to close it in a racetrack-like manner becomes insufficient, and the discharge tends to become unstable. On the other hand, if it is greater than 20%, the reduction of damage energy is insufficient. If the central portion is designed to be longer, it is technically possible to reduce damage energy even when the ratio is greater than 20%, but this would lead to an increase in the size of not only the stone unit and cylindrical target but also the device itself, which would be disadvantageous in terms of cost, etc. Furthermore, in the present invention, the magnet unit has a support made of a magnetic material that supports a pair of magnets, and the portion of the support located between the two magnets in the central part may be a gap. This makes it possible to reliably reduce the damage energy caused by the influence of magnetic field lines extending toward the object to be film-deposited.

[0012] Furthermore, in order to solve the above problems, the magnetron sputtering apparatus equipped with a rotary cathode unit for the magnetron sputtering apparatus further comprises a vacuum chamber that allows the placement of the substrate to be processed in the space opposite the rotary cathode unit in the Z-axis direction, a sputtering power supply for supplying power to the cylindrical target, and a gas introduction means for introducing sputtering gas into the vacuum chamber in a vacuum atmosphere, and is characterized in that a regulating plate is provided on both sides of the cylindrical target in the Y-axis direction at a distance from each other and positioned on the plane obtained by projecting the pair of magnets of the magnet unit in the Y-axis direction, and has a length equal to or greater than the cylindrical target (i.e., not only when it perfectly matches the target length, but also when it is longer than the target length), and functions as an anode.

[0013] Based on the above, it was confirmed that damage energy is further reduced compared to the case without a regulating plate. In this case, it is preferable that the distance in the Y-axis direction that connects the outer surface of the cylindrical target and the regulating plate in the shortest possible range be in the range of 50 mm to 170 mm. If the distance in the Y-axis direction is shorter than 50 mm, the adhesion efficiency to the substrate to be processed decreases, while if it is longer than 170 mm, the damage energy increases significantly. [Brief explanation of the drawing]

[0014] [Figure 1] A schematic diagram showing a vacuum processing system incorporating a magnetron sputtering apparatus equipped with the rotary cathode unit of this embodiment. [Figure 2] A schematic cross-sectional view of the magnetron sputtering apparatus of this embodiment, along the X-axis direction. [Figure 3] A schematic cross-sectional view of the magnetron sputtering apparatus of this embodiment, along the Y-axis direction. [Figure 4] A schematic cross-sectional view along the line IV-IV in Figure 3. [Figure 5] A perspective view of the magnet unit used in the rotary cathode unit of this embodiment. [Figure 6] A cross-sectional view along the line VI-VI in Figure 5. [Figure 7] A cross-sectional view along the line VII-VII in Figure 5. [Figure 8] A cross-sectional view along the line VIII-VIII in Figure 5. [Figure 9] A cross-sectional view along the line IX-IX in Figure 5. [Figure 10] (a) and (b) are graphs showing experimental results illustrating the effects of the present invention. [Modes for carrying out the invention]

[0015] Hereinafter, with reference to the drawings, an embodiment of the rotary cathode unit RC of the present invention and a magnetron sputtering apparatus SM including the rotary cathode unit RC, which are assembled to a cluster tool type vacuum processing system Cs, will be described. Hereinafter, the cylindrical target described later is made of IZO, and the film formation object is a glass substrate surface on which an organic layer and a cathode electrode layer are previously formed with a predetermined film thickness (hereinafter, this is simply referred to as "substrate Sg"). A case where an IZO film is formed on the surface of the substrate Sg (that is, the organic layer and the cathode electrode layer) by reactive sputtering in which oxygen gas is also introduced will be taken as an example. In the following, the directions such as up and down are based on the installation posture of the magnetron sputtering apparatus SM shown in FIGS. 2 and 3. Note that, although a case where the substrate Sg is arranged at a position facing a plurality of rotary cathode units RC for film formation will be described as an example, the present invention is not limited to this, and film formation can also be performed while relatively moving either one or both of the rotary cathode unit RC and the substrate Sg in one direction. Further, although a case where film formation is performed in a so-called depo-down manner will be described as an example, the present invention is not limited to this, and for example, the present invention can also be applied to a so-called depo-up manner or a side-depo manner.

[0016] Referring to Figure 1, the vacuum processing system Cs comprises a central transport chamber Tc where a transport robot Rt for transporting substrates Sg is positioned, and a plurality of processing chambers Pc1 to Pc6 and a plurality of load lock chambers Lc (2 in this embodiment) connected to the side walls of the transport chamber Tc, respectively, so as to surround the transport chamber Tc. At least one processing chamber Pc1 constitutes the vacuum chamber of the magnetron sputtering apparatus SM of the present invention. Vacuum pumps and vent valves (not shown) are connected to the transport chamber Tc and load lock chamber Lc, allowing switching between an atmospheric atmosphere and a vacuum atmosphere. A so-called frogleg type transport robot Rt equipped with two robot hands Rt1, Rt1 is used. As known robots can be used, further explanation, including their transport operation, is omitted. The transport robot Rt is controlled according to a pre-set sequence to sequentially transport the substrates Sg, and various vacuum processing is sequentially performed on each substrate Sg in each processing chamber Pc1 to Pc6.

[0017] Referring to Figures 2 to 4, an exhaust port 11 is provided on the wall of the processing chamber Pc1 of the magnetron sputtering apparatus SM. An exhaust pipe 13 from a vacuum pump 12, which consists of a rotary pump, cryopump, turbomolecular pump, etc., is connected to the exhaust port 11, allowing the processing chamber Pc1 to be evacuated to a predetermined pressure. A gas inlet 14 is also provided on the wall of the processing chamber Pc1, and a gas inlet pipe 15 from a gas source (not shown) is connected to the gas inlet 14. A flow control valve 16, such as a mass flow controller, is interposed in the gas inlet pipe 15, allowing argon gas (rare gas) or oxygen gas (reaction gas) as sputtering gas with controlled flow rate to be introduced into the processing chamber Pc1. In this embodiment, the gas inlet pipe 15 and the flow control valve 16 constitute the gas introduction means. A substrate stage 2, on which a substrate Sg is placed with its film-forming surface (the surface on which the organic layer and cathode electrode layer are formed) facing upwards, is arranged via an insulator 21 in the lower part of the processing chamber Pc1. The substrate stage 2 can be equipped with an electrostatic chuck for adsorbing the substrate Sg and a substrate heating and cooling mechanism, although these are not specifically illustrated and described. Multiple rotary cathode units RC of this embodiment are provided in the upper part of the processing chamber Pc1, facing the substrate Sg. In the following, the two orthogonal directions within the film deposition surface of the substrate Sg will be referred to as the X-axis direction and the Y-axis direction, and the direction perpendicular to the X-axis and Y-axis will be referred to as the Z-axis direction.

[0018] Each rotary cathode unit RC installed at equal intervals in the Y-axis direction includes a cylindrical target 3 that is longitudinally extended in the X-axis direction, drive means 4 that rotatably drives the cylindrical target 3 about the X-axis respectively, and a magnet unit 5 that is assembled inside the cylindrical target 3 and generates a magnetic field that leaks into the space below the cylindrical target 3 in the Z-axis direction so that a line passing through a position where the vertical component of the magnetic field becomes zero extends along the X-axis direction and closes in a racetrack shape. The drive means 4 includes a drive block 41 installed at the upper part inside the processing chamber Pc1 with an interval in the X-axis direction and connected to one end of the cylindrical target 3 in the X-axis direction, and a support block 42 connected to the other end. A drive motor 41a that rotatably drives the cylindrical target 3 about the X-axis at a predetermined rotational speed is assembled to the drive block 41. Although not particularly illustrated and described, a refrigerant circulation path for circulating a refrigerant for cooling the cylindrical target 3 and an output cable from a sputtering power supply for applying a predetermined power to each cylindrical target 3 are connected to the drive block 41. Since any of these can use known ones, further explanation is omitted. As a sputtering power supply not shown in the figure, a known power supply for applying pulsed DC power or a high-frequency power supply can be used. As shown in an enlarged view in Fig. 3, the cylindrical target 3 is composed of a cylindrical backing tube 31 and a cylindrical IZO target material 32 joined to the backing tube 31 via a bonding material (not shown) such as indium or tin, and is sized to have an X-axis direction length equal to or greater than the X-axis direction length of the substrate Sg. A tube body 33 is inserted into the backing tube 31 with a gap from its inner surface, and the magnet unit 5 is disposed inside the tube body 33.

[0019] Referring also to Figure 5, the magnet unit 5 comprises a rotating shaft 51 whose ends are pivotally supported by a drive block 41 and a support block 42, respectively, a support (yoke) 52 made of magnetic material connected to the rotating shaft 51, and magnets 53 provided on the outer surface of the support 52. The rotating shaft 51 can also be rotated around its axis by another motor (not shown) provided on the drive block 41, and the support 52, and consequently the magnets 53, can be tilted within a predetermined angular range with respect to the Z axis. Furthermore, when the substrate Sg is facing the rotating cathode unit RC, the magnet unit 5 is divided into a central portion 51 with a length equal to the X-axis length of the substrate Sg, peripheral portions 52 located on both sides of the central portion 51 along the X axis and forming the corners of the racetrack, and additional corner portions 53 located on both outer sides of the peripheral portion 52 along the X axis and forming the corners of the racetrack together with the peripheral portion 52. In this embodiment, the central portion 51 is described as being equivalent to the length of the substrate Sg in the X-axis direction, but it is not limited to this.

[0020] The central portion 51 is the magnetic field portion that extends substantially linearly in the X-axis direction of the racetrack-like closing magnetic field. The X-axis length of the central portion 51 is appropriately set according to the thickness and quality distribution of the thin film to be deposited, the type of target material 32, and the pressure of the processing chamber Pc1 during film deposition. This includes not only cases where the X-axis length of the central portion 51 is shorter than that of the substrate Sg, but also cases where it is slightly longer than that of the substrate Sg (for example, when both ends of the substrate Sg in the X-axis direction are located below the peripheral portion 52). In this specification, "equivalent" does not only mean cases where the length of the central portion 51 perfectly matches the X-axis length of the substrate Sg, but also cases where it is slightly smaller or larger than the X-axis length of the substrate Sg. Furthermore, the ratio of the central portion 51 to the X-axis length (total length) of the cathode unit RC is set in the range of 50% to 95%. If the proportion of the central portion 51 is less than 50%, the reduction of damage energy will be insufficient, while if it is greater than 95%, the formation of the magnetic field necessary to close it in a racetrack shape will be insufficient, making the discharge prone to instability. On the other hand, the proportion of the peripheral portion 52 to the X-axis length (total length) of the cathode unit RC is set in the range of 5% to 35%. If the proportion of the peripheral portion 52 is less than 5%, the formation of the racetrack between the central portion 51 and the additional corner portion 53 will be distorted, making the discharge prone to instability, while if it is greater than 35%, the reduction of damage energy will be insufficient. Furthermore, the proportion of the additional corner portion 53 to the X-axis length (total length) of the cathode unit RC is set in the range of 1% to 20%. If the proportion of the additional corner portion 53 is less than 1%, the formation of the magnetic field necessary to close it in a racetrack shape will be insufficient, making the discharge prone to instability, while if it is greater than 20%, the reduction of damage energy will be insufficient.

[0021] Referring to Figures 6 to 9, the support 52 comprises a plate-shaped base end 52a substantially parallel to the substrate Sg, and skirt portions 52b, 52b that rise from both ends in the Y-axis direction upward in the Z-axis direction, with the distance from the midpoint Cp of the base end 52a continuously increasing as it moves upward in the Z-axis direction. Normally, the midpoint Cp of the base end 52a is positioned on the axis in the Z-axis direction (reference position). In the first part of the support 52 that constitutes the central portion 51, as shown in Figure 6, the outer surfaces of the skirt portions 52b, 52b are formed in the shape of convex peaks, and a pair of magnets 53a, 53b are provided on the slopes on both sides of the peak, with their outer surface polarities differing from each other. Neodymium magnets of the same magnetization are used as the magnets 53a, 53b, and for example, integrally molded rod-shaped magnets with a substantially square cross-section can be used. As a result, a tunnel-shaped magnetic field Mf1 acts, leaking through each cylindrical target 3. At this time, the first angle α1 formed by the position where the vertical component of the magnetic field Mf1 is zero (B⊥0) and the center line in the Z-axis direction passing through the rotation center of the rotation axis 51 (and thus the cylindrical target 3) is set to be in the range of 50 to 75 degrees, so that the magnetic field strength on the outer surface of the cylindrical target 3 is in the range of 1000G to 3000G. In addition, in the first part of the support 52, there is a gap 52c between one of the magnets 53a, 53a where the base end 52a does not exist. The base end 52a and both skirt portions 52b, 52b are connected to the rotation axis 51 via a support culm 54. In Figure 6, the member indicated by reference numeral 55 serves as a so-called balance weight or support guide.

[0022] In the second part of the support 52 that constitutes the peripheral portion 52, the part adjacent to the central portion 51 has the outer surfaces of the skirt portions 52b, 52b formed in a convex, mountain-like shape, as shown in Figure 7, but one of the inclined surfaces located radially inward extends to the base end portion 52a. The inclined surfaces on both sides of this apex are used as magnet mounting surfaces. Furthermore, in the second part of the support 52, as it moves outward in the X-axis direction, one of the inclined surfaces is moved stepwise (in four steps) toward the base end portion 52a, and in the second part of the support 52 adjacent to the additional corner portion 53, as shown in Figure 8, one of the inclined surfaces is formed at the base end portion 52a. On each inclined surface, as shown above, a pair of magnets 53c, 53d are provided with opposite polarities on their outer surfaces. Neodymium magnet pieces of the same magnetization can be used as the pair of magnets 53c, 53d. As a result, a tunnel-like magnetic field Mf2 acts, leaking through each cylindrical target 3. At this time, the first angle α2 formed by the position where the vertical component of the magnetic field Mf2 is zero (B⊥0) and the center line in the Z-axis direction passing through the rotation center of the rotation axis 51 (and thus the cylindrical target 3) is set to be in the range of 20 to 70 degrees, and the angle α2 decreases as the magnet unit 5 moves outward in the X-axis direction (that is, the position where the vertical component of the magnetic field Mf2 is zero (B⊥0) gradually decreases downward in the Z-axis direction), so that the magnetic field strength on the outer surface of the cylindrical target 3 is in the range of 400G to 3000G. The base end portion 52a and both skirt portions 52b, 52b that constitute the second part are connected to the rotation axis 51 via the support culm 54, as described above.

[0023] As shown in Figure 9, the additional corner portion 53 is provided with a tongue-shaped support plate portion 56 that protrudes outward in the Y-axis direction from the support body 52. ​​The outer surface of the support plate portion 56 is provided with a rod-shaped central magnet 53e extending in the X-axis direction and rod-shaped peripheral magnets 53f arranged at intervals on both sides of the central magnet 53e in the Y-axis direction (i.e., peripheral magnets 53f are arranged on both sides of one central magnet 53e in the Y-axis direction), and a closed-loop leakage magnetic field Mf3 acts between the central magnet 53e and the two peripheral magnets 53f in balance. In this embodiment, other peripheral magnets 53g are provided so as to surround the outer end in the X-axis direction and both sides in the Y-axis direction of the central magnet 53e, with the polarity on the substrate Sg side being reversed from that of the central magnet 53e. As described above, neodymium magnet pieces of the same magnetization can be used as the central magnet 53e and the peripheral magnets 53f, 53g. At this time, the third angle α3 formed by the position where the vertical component of the magnetic field Mf3 is zero (B⊥0) and the center line in the Z-axis direction passing through the rotation center of the rotation axis 51 (and thus the cylindrical target 3) is 50 degrees or less, so that the magnetic field strength on the outer surface of the cylindrical target 3 is in the range of 100G to 1500G.

[0024] The support plate portion 56 is connected to the rotating shaft 51 via the support culm 54, as described above. With the magnet unit 5 configured as described above, as shown by the dashed line in Figure 5, the line passing through the position where the vertical component B⊥0 of the magnetic field Mf1 to Mf3 is zero extends along the X-axis direction and closes in a racetrack shape. In this case, in the reference orientation of the magnet unit 5, the line passing through the position where the vertical component B⊥0 of the magnetic field in the central portion 51 is zero extends in a roughly linear shape along the X-axis direction, and is positioned above the Z-axis direction compared to the peripheral portion 52 and the additional corner portion 53 (in Figure 5, which is shown upside down, the vertical component B⊥0 of the magnetic field in the central portion 51 is positioned below the Z-axis direction compared to the peripheral portion 52 and the additional corner portion 53). In other words, it is positioned away from the film deposition surface of the substrate Sg in the Z-axis direction.

[0025] On the upper inner surface of the processing chamber Pc1, earth-grounded regulating plates 6 are suspended at intervals on both sides of the cylindrical target 3 in the Y-axis direction to function as anodes during sputtering film deposition and to reliably reduce damage energy to the substrate Sg. At least a portion of the regulating plates 6 is positioned on the plane projected in the Y-axis direction from a pair of magnets 53a to 53f of the magnet unit 5. The regulating plates 6 have a length equal to or greater than that of the cylindrical target 3, and the Y-axis distance Ds connecting the outer surface of the cylindrical target 3 and the regulating plates 6, as shown in Figure 3, is in the range of 50 mm to 170 mm. If the Y-axis distance is shorter than 50 mm, the adhesion efficiency to the substrate Sg decreases, while if it is longer than 170 mm, the damage energy increases significantly. In this embodiment, the lower end 6a of the regulating plates 6 is set at the same height as the lowest point 3a of the cylindrical target 3, but it is not limited to this, and the lower end 6a of the regulating plates 6 may be located above or below the lowest point 3a of the cylindrical target 3. However, the higher the lower end 6a of the regulating plate 6 is positioned above the lowest point 3a of the cylindrical target 3, the greater the damage energy tends to be. Therefore, it is preferable to use the position where the lowest point 3a and the lower end 6a coincide in the Z-axis direction as the reference point, and position the lower end 6a of the regulating plate 6 within a range of -50mm to 100mm from the reference point relative to the lowest point 3a (in this case, a lower end 6a below the reference point (towards the substrate Sg) is considered +, and a lower end 6a above the reference point (away from the substrate Sg) is considered -). Furthermore, although we will explain using the example of a regulating plate 6 suspended from the upper inner surface of the processing chamber Pc1, it is sufficient that a part of the regulating plate 6 is positioned on the plane obtained by projecting the pair of magnets 53a to 53f of the magnet unit 5 in the Y-axis direction, and the mounting method and shape of the regulating plate are not specified.

[0026] When depositing an IZO film using the sputtering apparatus SM described above, the substrate Sg is transported to the processing chamber Pc1 by the transport robot Rt, positioned on the upper surface of the substrate stage 2, and then the processing chamber Pc1 is evacuated to a predetermined pressure. When the processing chamber Pc1 reaches the predetermined pressure, argon gas and oxygen gas are introduced at predetermined flow rates, and while each cylindrical target 3 is rotated around the X axis at a predetermined speed by the drive block 41, pulsed DC power and high-frequency power are supplied to each cylindrical target 3 by a sputtering power supply (not shown). As a result, plasma is formed in the space between each cylindrical target 3 and the substrate Sg within the processing chamber Pc1. This causes the target material 32 of each cylindrical target 3 to be sputtered by ions of rare gas in the plasma, and an IZO film is deposited on the upper surface of the substrate Sg.

[0027] According to the above embodiment, the damage energy (flux (number) × kinetic energy) applied to the upper surface (film deposition surface) of the substrate Sg is significantly reduced, and it is confirmed that the attenuation of PL intensity when an IZO film is deposited using the magnetron sputtering apparatus SM can be significantly suppressed. Furthermore, by gradually decreasing the second angle α2 as it moves outward in the X-axis direction, the difference in density of orbiting electrons in the peripheral portion 52 and the additional corner portion 53 before and after the orbiting electrons change direction can be reduced, and moreover, the scattering of orbiting electrons toward the substrate Sg after the direction change can be suppressed. Note that the line passing through the position where the vertical component B⊥0 of the magnetic field in the central portion 51 is zero is the peripheral portion. If the cylindrical target 3 is configured to be located above the Z-axis direction compared to the portion 52 and the additional corner portion 53, there is a risk that the adhesion efficiency to the substrate Sg when sputtering the cylindrical target 3 will decrease. In such cases, the adhesion efficiency can be improved by setting the so-called TS distance between the cylindrical target 3 and the substrate Sg to a shorter distance (for example, 130 mm or less). At this time, in the standard orientation of the magnet unit 5, the void portion 52c of the support 52 faces the film deposition surface of the substrate Sg (in other words, there are no magnets present), so even if the magnetic field strength is increased to 3000 G as described above, problems such as an increase in damage energy due to the influence of magnetic field lines extending toward the substrate Sg do not occur.

[0028] To confirm the above effects, the following experiment was conducted using a vacuum processing system Cs equipped with the magnetron sputtering apparatus SM described above. In this experiment, the object to be deposited was a glass substrate. For example, an Alq3 film as an organic layer was deposited on one side of the glass substrate with a thickness of 40 nm in another processing chamber Pc2, and then transported to processing chamber Pc1 while maintaining a vacuum atmosphere. The cylindrical target 3 placed in processing chamber Pc1 was made of IZO (In2O3:ZnO=9:1). In this case, multiple cylindrical targets 3 were installed at equal intervals in the Y-axis direction, and the distance between TS was set to 80 mm. The magnet unit 5 was configured such that the first angle α1 at the central part 51 was 70 degrees and the magnetic field strength on the outer surface of the cylindrical target 3 was 1300 G. As for the deposition conditions, the sputtering power supply was set to a pulsed DC power supply with a frequency of 20 kHz and an input power of 30 kW, and the rotation speed of the cylindrical target 3 during deposition was set to 10 rpm. Argon and oxygen gases were used as sputtering gases, introduced into the vacuum chamber at flow rates of 170 sccm for argon and 5 sccm for oxygen. The vacuum chamber pressure during sputtering was maintained at 0.4 Pa, and an IZO film was deposited on the substrate Sg (i.e., the Alq3 film surface) with a thickness of 100 nm. Simulation of the collision of positive ions with the deposition surface of the object during deposition showed that the product of the flux (number) of positive ions per unit area and the kinetic energy of the positive ions (damage energy) was 1.36E+17 (eV / m²). 2 It was / sec).

[0029] As a comparative experiment, instead of the magnet unit 5 of the present invention, the conventional magnet unit described above (i.e., having a central magnet positioned along the X-axis on the upper surface of the support facing the object to be deposited, and peripheral magnets surrounding this central magnet at equal intervals, with the polarity on the object side reversed) was used, and an IZO film was deposited under the same conditions as above. However, the distance between TS was set to 210 mm, and the magnetic field strength on the outer surface of the cylindrical target 3 was set to 800 G. When the collision of positive ions with the deposition surface of the object to be deposited was simulated during film deposition, the damage energy was found to be 1.02E+18 (eV / m). 2The value was found to be approximately one order of magnitude larger than that of the present invention. Immediately after the IZO film was deposited, the PL emission intensity was measured by irradiating the organic film with excitation light at a wavelength of 365 nm using a spectrofluorometer (manufactured by JASCO Corporation).

[0030] Based on the above, using a glass substrate with an Alq3 film deposited to a thickness of 40 nm on one side as the reference product, the decrease in PL intensity from the reference product was approximately 50% in the comparative experiment, while the decrease in Experiment 1 was approximately 32%, confirming that the decrease in PL intensity compared to the organic layer alone before the IZO film deposition can be reduced. From Experiment 1, it can be seen that by spacing the line passing through the position where the vertical component of the magnetic field in the central part 51 of the magnet unit 5 is zero downward in the Z-axis direction compared to the peripheral part 52 and the additional corner part 53, the damage energy is reduced and the attenuation of PL intensity due to film deposition can be suppressed.

[0031] Next, in Experiment 2, using the magnetron sputtering apparatus SM from Experiment 1, earth-grounded regulating plates 6 were suspended at intervals on both sides of the cylindrical target 3 along the Y-axis. At this time, the lower end 6a of the regulating plate 6 and the lowest point 3a of the cylindrical target 3 were at the same height in the Z-axis direction. Then, an IZO film was deposited under the same conditions as above. When the collision of positive ions with the deposition surface of the object during deposition was simulated, the damage energy was found to be 1.24E+16(eV / m). 2The time ( / sec) was found to be approximately an order of magnitude smaller than that of Experiment 1. When the PL emission intensity was measured immediately after the IZO film was deposited, the decrease in PL intensity from the reference product was approximately 15%. Next, when the distance Ds in the Y-axis direction connecting the outer surface of the cylindrical target 3 and the regulating plate 6 was appropriately varied in the range of 30 mm to 250 mm, it was confirmed that the damage energy increased significantly when the distance Ds exceeded 170 mm, as shown in Figure 10(a). Furthermore, when the position of the lower end 6a of the regulating plate 6 was appropriately changed relative to the above reference point, the damage energy changed logarithmically (in Figure 10(b), the vertical axis is a logarithmic plot), and it was found that when the position of the lower end 6a of the regulating plate 6 relative to the reference point exceeded -50 mm (i.e., the lower end 6a of the regulating plate 6 is located above the lowest point 3a of the cylindrical target 3 in the Z-axis direction), the decrease in PL intensity tended to increase, and the above product increased.

[0032] Although embodiments of the present invention have been described above, various modifications are possible as long as they do not deviate from the technical concept of the present invention. In the above embodiments, the magnetron sputtering apparatus SM of the present invention was described as being assembled to a vacuum processing system Cs as an example, but the invention is not limited thereto, and can also be applied to a so-called in-line vacuum processing apparatus that performs film deposition while passing a substrate Sg through it. Furthermore, in the above embodiments, the example described was when the substrate Sg is positioned opposite a plurality of rotary cathode units RC and a predetermined thin film is deposited, but the invention is not limited thereto. For the purpose of improving productivity, for example, a transition metal oxide or nitride film of a predetermined thickness can be deposited as an initial layer on the surface of the substrate Sg in the processing chamber Pc1 which constitutes the vacuum chamber of the magnetron sputtering apparatus SM of the present invention, and then the substrate Sg can be transported to another processing chamber Pc2 in which a cathode unit is arranged as in the conventional example above, and a film can be deposited to a desired thickness.

[0033] In the above embodiment, a support 52 formed integrally was described as an example, but it is not limited to this, and parts of the support 52 may be individually manufactured according to the angle between the position where the vertical component of the magnetic field is zero (B⊥0) and the center line of the rotation axis 51, and each of these manufactured parts may be connected to the rotation axis. Also, in the above embodiment, an example was described in which an additional corner portion 53 is provided in order to further suppress the scattering of circumferential electrons toward the substrate Sg, but this can be omitted depending on the length of the central portion 51 relative to the X-axis length of the substrate Sg. On the other hand, a configuration in which only a pair of magnets (not shown) are placed on both outer sides in the X-axis direction of the peripheral portion 52 can be adopted, and in this case, other peripheral magnets may be provided so as to surround the outer end in the X-axis direction. Furthermore, in the above embodiment, an example was described in which an IZO film is deposited by reactive sputtering, but the present invention can be broadly applied not only to the deposition of oxides and nitrides of other transition metals, but also in cases where damage energy to the object to be deposited is a problem.

[0034] Furthermore, although the above embodiment was described using a regulating plate 6 suspended from the upper inner surface of the processing chamber Pc1 and grounded as an example, the invention is not limited to this, as long as the regulating plate 6 functions as an anode during film formation. For example, the regulating plate 6 may be provided in an electrically floating state, and a bias may be applied during film formation to control the electromagnetic field. In the above embodiment, the invention was described using a case where an organic layer or cathode electrode layer is pre-formed on the surface of a glass substrate with a predetermined thickness, and an IZO film is formed on that surface. However, the present invention can be broadly applied even when the underlying layer is, for example, gold, silver, copper, aluminum, or an alloy thereof. [Explanation of symbols]

[0035] SM...Magnetron sputtering apparatus, RC...Rotating cathode unit, Pc1...Processing chamber (vacuum chamber), 3...Cylindrical target, 4...Driver, 5...Magnet unit, 51...Central part of magnet unit, 52...Peripheral part of magnet unit, 53...Additional corner part, 52...Support, 53, 53a~53f...Magnets, 6...Regulating plate, Sg...Substrate (object to be deposited), Mf1~Mf3...Magnetic field, Ds...Y-axis distance connecting the outer surface of the cylindrical target and the regulating plate in the shortest possible way.

Claims

1. A rotary cathode unit for a magnetron sputtering apparatus, positioned in a vacuum chamber facing the film deposition surface of the object to be deposited, With two orthogonal directions defined as the X-axis and Y-axis directions, and the direction perpendicular to the X-axis and Y-axis defined as the Z-axis direction, the cathode unit comprises a cylindrical target with a longitudinal length in the X-axis direction, a driving means for rotating the cylindrical target around the X-axis, and a magnet unit assembled inside the cylindrical target that generates a magnetic field leaking from the cylindrical target such that a line passing through a position where the vertical component of the magnetic field is zero extends along the X-axis direction and closes in a racetrack-like manner, A rotary cathode unit for a magnetron sputtering apparatus, characterized in that the magnet unit has peripheral portions on both sides in the X-axis direction that form the corners of the race track, and a central portion located between the peripheral portions, and the line passing through the position where the vertical component of the magnetic field in the central portion is zero is spaced further away from the film deposition surface in the Z-axis direction compared to the peripheral portions.

2. The magnet unit comprises a pair of magnets arranged with their polarity reversed on the film-forming surface side, The first angle between the position where the vertical component of the magnetic field generated by a pair of magnets extending in the X-axis direction in the central part becomes zero and the center line in the Z-axis direction passing through the rotation center of the cylindrical target is in the range of 50 to 75 degrees. A rotary cathode unit for a magnetron sputtering apparatus according to claim 1, characterized in that the second angle between the position where the vertical component of the magnetic field generated by a pair of magnets in the peripheral area becomes zero and the Z-axis axis passing through the rotation center of the cylindrical target is in the range of 20 to 70 degrees.

3. The rotary cathode unit for a magnetron sputtering apparatus according to claim 2, characterized in that the second angle is configured to decrease continuously or stepwise as it moves outward in the X-axis direction.

4. The rotary cathode unit for a magnetron sputtering apparatus according to claim 2, wherein the magnet unit further comprises additional corner portions on both outer sides in the X-axis direction of the peripheral portion, and the additional corner portions are provided with a rod-shaped central magnet extending in the X-axis direction and rod-shaped peripheral magnets spaced apart on both sides of the central magnet in the Y-axis direction, thereby generating a closed-loop magnetic field that is balanced between the central magnet and the two peripheral magnets.

5. The rotary cathode unit for a magnetron sputtering apparatus according to claim 2, characterized in that the magnet unit has a support made of a magnetic material that supports the pair of magnets, and the portion of the support located between the two magnets in the central part is a gap.

6. A magnetron sputtering apparatus comprising a rotary cathode unit for a magnetron sputtering apparatus according to any one of claims 1 to 5, a vacuum chamber that allows the placement of a substrate to be processed in a space facing the rotary cathode unit in the Z-axis direction, a sputtering power supply for supplying power to a cylindrical target, and a gas introduction means for introducing sputtering gas into the vacuum chamber in a vacuum atmosphere, A magnetron sputtering apparatus characterized in that a regulating plate having a length equal to or greater than the cylindrical target and functioning as an anode is provided on both sides of the cylindrical target in the Y-axis direction, with a gap between them, and positioned on a plane projected in the Y-axis direction from a pair of magnets of a magnet unit.

7. The sputtering apparatus according to claim 6, characterized in that the distance in the Y-axis direction connecting the outer surface of the cylindrical target and the regulating plate is in the range of 50 mm to 170 mm.

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