Magnetron sputtering apparatus

Abstract

To provide a magnetron sputtering apparatus that can deposit a predetermined thin film with good in-plane uniformity of the film quality. [Solution] The magnetron sputtering apparatus SM1 of the present invention has a vacuum chamber 1 in which a target 2 and a substrate Sg are arranged opposite each other, a shield plate 4 arranged to surround the target and function as an anode during sputtering of the target, and a magnet unit 3 that applies a leakage magnetic field to the film deposition space between the target and the substrate. The lower surface of the shield plate, which is in the direction from the target to the substrate, is provided with a cylindrical wall portion 40 that extends downward for a predetermined length from a position close to the edge of the target.

Description

Technical Field

[0001] The present invention relates to a magnetron sputtering apparatus having a vacuum chamber in which a target and a substrate are disposed opposite to each other, a shield plate disposed so as to surround the periphery of the target and functioning as an anode during sputtering of the target, and a magnet unit that applies a leakage magnetic field to a film-forming space between the target and the substrate.

Background Art

[0002] In the manufacturing process of flat panel displays, there is a film-forming process of forming various thin films on the surface of a glass substrate (hereinafter referred to as "substrate") having a rectangular contour. During the film-forming process, the substrate may be heated to a predetermined temperature and then film is formed. The size of the substrate to be film-formed is increasing with the progress of generations (for example, 2300 mm × 2700 mm in the G8.7 generation), and its plate thickness is also thin (for example, 0.5 mm). A magnetron sputtering apparatus for film-forming on such a substrate is known, for example, from Patent Document 1. This apparatus includes a vacuum chamber in which a substrate and a single target having an area slightly larger than that of the substrate are disposed opposite to each other. A plurality of magnet units are arranged in parallel at intervals in one direction on the side facing away from the sputtering surface of the target, and during film formation, each magnet unit is reciprocated at a predetermined speed in the direction of parallel arrangement. Further, a frame-shaped shield plate is installed around the target so as to surround it, and it functions as an anode during sputtering. Generally, one surface of the shield plate is provided at a height position equivalent to the sputtering surface of the target when the target is not in use. ]>

[0003] Generally, a magnetic unit is used that includes a central magnet arranged linearly on one side of a rectangular support plate (yoke) provided parallel to the target, and peripheral magnets surrounding the central magnet, each having linear sections extending parallel to each other at equal intervals on both sides of the central magnet, and bridging sections connecting the free ends of both linear sections, with the polarity on the target side reversed. As a result, a magnetic field leaks from the sputtering surface into the deposition space such that a line passing through a position where the vertical component of the magnetic field is zero extends in the X-axis direction and closes in a racetrack shape. When a sputtering gas such as argon gas is introduced into a vacuum chamber with a vacuum atmosphere, and a DC power with, for example, a negative potential is applied to the target, multiple racetrack-shaped plasmas are formed in the deposition space, the target is sputtered by ions of the sputtering gas in the plasma, and sputtered particles scattered from the target according to a predetermined cosine law adhere to and deposit on the substrate surface, forming a predetermined thin film.

[0004] Here, when the target is made of molybdenum with a predetermined composition, and a molybdenum film whose crystal structure is easily altered by the substrate temperature during film formation is deposited on the substrate surface using the magnetron sputtering apparatus described above, it was found that there are regions with relatively high sheet resistance values ​​at the outer edge of the substrate (especially on both ends in the reciprocating direction of the magnet unit), and that the in-plane uniformity of the film quality, such as the sheet resistance value, cannot be increased. Therefore, the inventors diligently conducted research and came to the following conclusion. Specifically, when simulating the trajectories and density of electrons and secondary electrons (hereinafter referred to as "circulating electrons") in the plasma that is circulating along the racetrack in the above-mentioned conventional example, it was found that in the magnet units located at both ends in the parallel arrangement direction, a large amount of circulating electrons diverge toward the substrate on both ends in the longitudinal direction. This is thought to be because, although it was thought that the entire surface of the shield plate that can directly observe the film formation space would function as an anode when the plasma is formed in the film formation space, in reality, only a part of the surface of the shield plate that is close to the target functions as an anode, and the plasma density distribution is non-uniform. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-1376 [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention is based on the above findings and aims to provide a magnetron sputtering apparatus that can deposit a predetermined thin film with good in-plane uniformity of film quality. [Means for solving the problem]

[0007] To solve the above problems, the magnetron sputtering apparatus of the present invention has a vacuum chamber in which a target and a substrate are arranged facing each other, a shield plate arranged to surround the target and function as an anode during sputtering of the target, and a magnet unit that applies a leakage magnetic field to the film deposition space between the target and the substrate, and is characterized in that the lower surface of the shield plate, which is in the direction from the target to the substrate, has a cylindrical wall portion that extends downward for a predetermined length from a position close to the edge of the target.

[0008] Here, when a cylindrical wall portion extending downward for a predetermined length from a position close to the target edge is provided on the lower surface of the shield plate, and the orbits and density of orbiting electrons are simulated, it is found that in the magnet units located at both ends in the parallel arrangement direction, the divergence of orbiting electrons toward the substrate at both ends in the longitudinal direction is significantly suppressed compared to the conventional example described above. In this state, for example, when a molybdenum film is deposited, it was confirmed that the in-plane uniformity of the film quality, such as the sheet resistance value, can be improved. This is thought to be due to the improvement in the plasma density distribution because, when plasma is formed in the deposition space, the inner surface portion of the cylindrical wall portion that is close to the target and partially surrounds the deposition space also functions as an anode in addition to the shield plate (in other words, the area that functions as an anode has increased compared to the conventional example described above).

[0009] Incidentally, when a cylindrical wall portion is provided as described above, sputtered particles scattered from the target directly adhere to the inner surface of the cylindrical wall portion that partially surrounds the film deposition space, and thus it also functions as an anti-adhesion plate to prevent sputtered particles from passing through to the space behind it. In the present invention, a configuration may be adopted in which other shielding plates are arranged around the substrate in the vacuum chamber, the cylindrical wall portion is designated as the upper cylindrical wall portion, and a lower cylindrical wall portion is provided on the upper surface of the other shield, having a length such that its upper end overlaps with the lower end of the upper cylindrical wall portion with a gap between them.

[0010] As described above, an anti-adhesion plate is formed within the vacuum chamber, enclosing the entire film deposition space with both shield plates and both cylindrical walls, thereby suppressing sputtered particles from circling through to the space behind them. In this case, since the upper cylindrical wall is located in close proximity to the target end (in other words, the anti-adhesion plate can be installed in a position moved inward into the vacuum chamber), the vacuum chamber can be miniaturized. During film deposition, it is also necessary to evacuate the film deposition space at a constant exhaust rate, so the lengths of the upper and lower cylindrical walls, the length of their overlap, and the size of the gap between them are appropriately set considering the exhaust conductance, etc. Other shield plates include, for example, when a substrate stage on which a substrate is placed is provided in the vacuum chamber, a shield plate that is placed around the substrate stage to prevent sputtered particles from circling through to the upper surface of the substrate stage exposed from the substrate and to the space behind the substrate stage. On the other hand, when a mask body that restricts the film deposition area on the substrate is provided in the vacuum chamber, the mask body may be used as another shield plate.

[0011] In the present invention, the lower cylindrical wall portion is designated as the first wall portion, and a second wall portion is further provided on the upper surface of another shield plate positioned around the first wall portion. The upper end of the upper cylindrical wall portion penetrates the gap between the first and second wall portions, thereby forming a labyrinth structure gap on the outer periphery of the film deposition space in which the lower cylindrical wall portion, the first wall portion, and the second wall portion interlock non-contact. This configuration is advantageous because it further suppresses the circling and passing of sputtered particles during film deposition. It is generally known that sputtered particles scattered from the target lose their kinetic energy and remain there after bouncing up to three times. Therefore, in addition to the anode mechanism, it is preferable to set the length of the first wall portion so that sputtered particles attempting to circling and passing through can be bounced as many times as possible between the opposing surfaces of the first wall portion and the lower cylindrical wall portion. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic cross-sectional view of a magnetron sputtering apparatus according to the first embodiment. [Figure 2] A graph showing the changes in discharge current and discharge voltage when a film is deposited using the magnetron sputtering apparatus of the first embodiment. [Figure 3] A schematic cross-sectional view of a magnetron sputtering apparatus according to the second embodiment. [Figure 4] (a) is an enlarged cross-sectional view of the main part of the magnetron sputtering apparatus shown in Figure 3, and (b) is an enlarged cross-sectional view of the main part when the stage body is moved to the substrate transfer position. [Figure 5] Figure 3 shows an enlarged cross-sectional view of another key part of the magnetron sputtering apparatus. [Modes for carrying out the invention]

[0013] Hereinafter, with reference to the drawings, embodiments of the present invention will be described using as an example an application to a magnetron sputtering apparatus that deposits a film on one side of a predetermined-size glass substrate with a rectangular outline (hereinafter referred to as "substrate Sg") using a deposit-down method. In the following, directions that are mutually orthogonal within the upper surface of the stage body described later will be referred to as the X-axis direction and the Y-axis direction, and directions that are orthogonal to the X-axis direction and the Y-axis direction will be referred to as the Z-axis direction. The terms indicating directions will be based on Figure 1, which shows the installation position of the magnetron sputtering apparatus.

[0014] Referring to Figure 1, the magnetron sputtering apparatus SM1 of the first embodiment includes a vacuum chamber 1. An exhaust port 11 is provided in the side wall (or bottom wall) of the vacuum chamber 1. The exhaust port 11 is connected to a vacuum pump 13, such as a rotary pump or cryopump, via an exhaust pipe 12, and the inside of the vacuum chamber 1 can be evacuated to a predetermined pressure. A gas inlet 14 is also provided in the side wall of the vacuum chamber 1 for introducing sputtering gas consisting of a noble gas such as argon (which may also include reaction gases such as oxygen). The gas inlet 14 is connected to a gas source (not shown) via a gas introduction pipe 16 interposed with a mass flow controller 15, and the flow rate-controlled sputtering gas can be introduced into the vacuum chamber 1 (i.e., the film deposition space 1a between the target 2 and the substrate Sg). A cathode unit Uc is detachably attached to the top wall of the vacuum chamber 1.

[0015] The cathode unit Uc comprises a single target 2 having a contour corresponding to the substrate Sg and an area slightly larger than the substrate Sg, and a plurality of magnet units 3 (six in this embodiment) arranged in parallel at equal intervals in the X-axis direction, positioned above the target 2 in the Z-axis direction (on the side facing away from the sputtering surface 21 of the target 2 and outside the vacuum chamber 1). The target 2 is selected according to the composition of the thin film to be deposited on the substrate Sg surface and is manufactured in a substantially rectangular parallelepiped shape in plan view using known methods. The magnetron sputtering apparatus SM1 of the first embodiment is particularly effective for depositing molybdenum films and tungsten films, whose crystal structure is easily altered by the substrate temperature during deposition. A backing plate 22 is bonded to the upper surface of the target 2, and during sputtering of the target 2, a coolant can be circulated through the backing plate 22 to cool the target 2. The target 2 is provided on the upper part of the vacuum chamber 1 via an insulating plate 23, with its sputtering surface 21 facing the substrate Sg with the inside of the vacuum chamber 1 facing the vacuum chamber 1. The output 24a from the sputtering power supply 24 is connected to the target 2 via the backing plate 22, allowing for the application of DC power with a negative potential or pulsed DC power to the target 2.

[0016] Inside the vacuum chamber 1, a frame-shaped shield plate 4 at ground potential is provided to prevent film deposition on the portion of the backing plate 22 that extends outward from the outer edge of the target 2, and on the wall portion of the vacuum chamber 1 located in the space behind the backing plate 22 (including components located in the space behind the back). The shield plate 4 functions as an anode during sputtering. The shield plate 4, designed to a predetermined width, is supported in the vacuum chamber 1 so that its lower surface is at the same height as the sputtering surface of the target 2 when not in use. The lower surface of the shield plate 4 is provided with a cylindrical wall portion (hereinafter referred to as the "upper cylindrical wall portion 40") that extends for a predetermined length downward in the Z-axis direction from a position close to the end of the target 2. The distance D1 between the end of the target 2 and the inner surface of the upper cylindrical wall portion 40 is set to a range of 5 mm to 20 mm, where the inner surface of the upper cylindrical wall portion 40 functions as an anode during sputtering of the target 2. Furthermore, it was confirmed that even when the distance D1 was set to 5 mm, the discharge voltage and discharge current remained stable at all times without inducing abnormal discharge (arc discharge). On the other hand, it was confirmed that when the distance D1 was set to a length longer than 20 mm, the in-plane uniformity of the sheet resistance could not be increased, as with the conventional method described above. A relatively long length from the shield plate 4 to the upper cylindrical wall portion 40 is advantageous, but it is necessary to set it appropriately considering the vacuum evacuation from the film deposition space 1a.

[0017] Each magnet unit 3 has the same shape and is provided with a magnetic material support plate (yoke) 31 that is longitudinal in the Y-axis direction and is positioned substantially parallel to the unused sputtering surface 21 of the target 2. On the lower surface of the support plate 31, a central magnet 32 ​​is provided linearly in the center, and peripheral magnets 33 are provided along the outer edge of the support plate 31 so as to surround the central magnet 32 ​​at predetermined intervals, with their upper polarities reversed. The magnet units 3 are arranged side by side such that the central magnets 32 of each magnet unit 3 are aligned in the Y-axis direction, with spacing in the X-axis direction, and the distance between the sputtering surface 21 and each magnet unit 3 is predetermined. The volume of the central magnet 32 ​​when converted to the same magnetization is designed to be equivalent to the sum of the volumes of each peripheral magnet 33 when converted to the same magnetization, and a closed-loop leakage magnetic field (not shown) that balances the deposition space 1a acts so that a line passing through the position where the vertical component of the magnetic field is zero extends along the direction of extension of the central magnet 32 ​​and closes in a racetrack-like manner. Since known magnet units 3 can be used, no further explanation is necessary. Each magnet unit 3 is connected to the drive shaft 51 of a drive means 5 such as a motor or air cylinder, and is moved back and forth as a single unit with a predetermined stroke value. A substrate stage St is positioned inside the vacuum chamber 1, facing the target 2.

[0018] The substrate stage St comprises a metal stage body St1 installed on the lower inner wall surface of the vacuum chamber via an insulator Is. The substrate Sg is placed on the upper surface of the stage body St1 with its opposing edges aligned in the X-axis and Y-axis directions, respectively. Although not specifically illustrated and described, a chuck plate of an electrostatic chuck with a contour matching the stage body St1 may be assembled to the stage body St1 to allow electrostatic adsorption of the substrate Sg during film deposition. Alternatively, a passage for refrigerant circulation and a heater may be assembled inside the stage body St1 to allow heating or cooling of the substrate Sg to a predetermined temperature during film deposition by sputtering of the target. As known components can be used for these, further detailed explanation is omitted. Furthermore, a frame-shaped shield plate Sd is arranged around the stage body St1 at ground potential as another shielding plate, preventing film deposition on the wall portion of the vacuum chamber 1 located around the stage body St1 and in the space behind it (including components located in the space behind it).

[0019] A lower cylindrical wall portion Sd1 is provided on the upper surface of the cider plate Sd, having a length such that its upper end overlaps with the lower end of the upper cylindrical wall portion with a gap Gp (in the X-axis direction). In the first embodiment, the cider plate Sd constitutes another shield plate. The length of the lower cylindrical wall portion Sd1 from the upper surface of the cider plate Sd is set within a range that does not unnecessarily obstruct the scattering path of sputtered particles scattered from the target 2, and the size of the gap Gp and the overlap length are set appropriately considering the exhaust conductance from the film deposition space 1a. In the first embodiment, the lower cylindrical wall portion Sd1 is positioned further inward into the vacuum chamber 1 than the upper cylindrical wall portion 40 so that film deposition on the upper surface of the cider plate Sd is suppressed as much as possible, but it is not limited to this, and the upper cylindrical wall portion 40 may be positioned further inward into the vacuum chamber 1 than the lower cylindrical wall portion Sd1.

[0020] According to the above, after placing the substrate Sg on the upper surface of the stage body St1, a sputtering gas such as argon gas (which may include a reactive gas such as oxygen gas or nitrogen gas) is introduced into the vacuum chamber 1 in a vacuum atmosphere, and DC power having, for example, a negative potential is applied to the target 2 by the sputtering power supply 24. Then, a (plurality of) racetrack-shaped plasmas are formed in the film formation space 1a, the target 2 is sputtered by the ions of the sputtering gas in the plasma, and the sputtered particles scattered from the target 2 according to a predetermined cosine law adhere to and deposit on the upper surface of the substrate Sg, forming a predetermined thin film. And when, for example, a molybdenum film is formed on the upper surface of the substrate Sg, it has been confirmed that the in-plane uniformity of the film quality such as the sheet resistance value can be improved. Further, since the upper cylindrical wall portion 40 is also used as a sputtering shield plate and the lower cylindrical wall portion Sd1 is provided on the other shield plate Sd, a sputtering shield plate surrounding the entire film formation space 1a between the target 2 and the substrate Sg is formed in the vacuum chamber 1, and the upper cylindrical wall portion 40 exists at a position close to the end of the target 2 (in other words, the sputtering shield plate can be installed in a state of being moved inward of the vacuum chamber 1), so that the vacuum chamber 1 can be miniaturized.

[0021] Here, as in the first embodiment, when a cylindrical wall portion 40 extending downward from a position close to the end of the target 2 is provided on the lower surface of the shield plate 4 and the orbits and densities of the circulating electrons are simulated, although not particularly illustrated and described, in the magnet units 3 respectively located at both ends in the X-axis direction (parallel arrangement direction), it has been confirmed that the divergence of the circulating electrons toward the substrate Sg side at both ends in the longitudinal direction is significantly suppressed as compared with the conventional one. From this, when plasma is formed in the film formation space 1a, in addition to the lower surface of the shield plate 4, the inner surface portion of the upper cylindrical wall portion 40 that is close to the target 2 and partially surrounds the film formation space also functions as an anode (in other words, the area functioning as an anode increases as compared with the conventional example), so that the plasma density distribution is improved and the in-plane uniformity of the film quality can be considered to have been improved.

[0022] To confirm the effects of the present invention, the following experiment was conducted using the sputtering apparatus SM1 of the first embodiment. That is, a G8.7 generation glass substrate was used as the substrate Sg, and after being positioned and installed on the upper surface of the stage body St1, a molybdenum film was formed with a film thickness of 250 nm, and the in-plane distribution of the sheet resistance value (Ω / □) in the plane of the substrate at that time was measured. As the sputtering conditions, a molybdenum target of a predetermined purity was used, and the TS distance between the target 2 and the substrate Sg was set to 135 mm. The distance D1 between the end of the target 2 and the inner surface of the upper cylindrical wall portion 40 and the length of the upper cylindrical wall portion 40 from the shield plate 4 were set to 5 mm and 115 mm, respectively. Also, during sputtering, Ar gas was introduced at 120 sccm so that the pressure in the vacuum chamber 1 was maintained at 0.2 Pa, and 200 kW of DC power was applied from the sputtering power supply 24 to the target 2 to sputter the target 2. During film formation, each magnet unit 3 was reciprocated at a predetermined speed with a predetermined stroke value in the X-axis direction. Prior to film formation, the glass substrate installed on the stage body St1 was preheated to 150 °C. As a comparative experiment, a shield plate 4 without the upper cylindrical wall portion 40 on its lower surface (however, an anti-deposition plate is provided so as to surround the film formation space 1a in front of the chamber wall surface 20 mm away from the end of the target 2: corresponding to the conventional example) was used, and a molybdenum film was formed with a film thickness of 250 nm under the same other conditions.

[0023] According to the above, in the comparative experiment, there were portions where the specific resistance value was higher on both end sides in the X-axis direction of the substrate Sg, and the in-plane distribution of the sheet resistance value was about ±9%. On the other hand, in the inventive experiment, it was confirmed that the in-plane distribution of the sheet resistance value was improved to about ±7%. Also, the changes in the discharge current and discharge voltage in the sputtering power supply during the inventive experiment and the comparative experiment were measured, and the results are shown in FIG. 2 (FIG. 2(a) is the comparative experiment, and FIG. 2(b) is the inventive experiment). According to this, even when a cylindrical wall portion 40 extending downward with a predetermined length from a position close to the end of the target 2 is provided, it was confirmed that the discharge voltage and the discharge current were always stable without inducing abnormal discharge (arc discharge), similar to the conventional example. Also, regarding the in-plane distribution of the film thickness, in the inventive experiment, it was equivalent to that of the comparative experiment (about ±9%).

[0024] Although the first embodiment of the present invention has been described above, various modifications are possible as long as they do not deviate from the technical concept of the present invention. In the first embodiment described above, a magnetron sputtering apparatus SM1 that deposits films using a deposit-down method was described, but the present invention is not limited thereto, and can also be applied to a sputtering apparatus that deposits films using a deposit-up method, for example. Furthermore, in the first embodiment described above, a substrate stage St is fixedly installed in the vacuum chamber 1 and the lower cylindrical wall portion is provided on another shield plate Sd as an example, but the present invention is not limited thereto, and a magnetron sputtering apparatus SM2 may be configured as follows.

[0025] Referring to Figures 3 to 5, the magnetron sputtering apparatus SM2 of the second embodiment includes a vacuum chamber 1. In the figures, the same reference numerals are used for components and parts as in the first embodiment, and specific descriptions are omitted. A substrate stage St is arranged within the vacuum chamber 1 so as to be movable in the vertical direction. The substrate stage St comprises a metal stage body 6, and as described above, a substrate Sg is placed on the upper surface of the stage body 6 with its opposing sides aligned in the X-axis and Y-axis directions, respectively. Known means for heating or cooling the substrate Sg placed on its upper surface may be incorporated into the stage body 6 so as to be able to control the substrate to a predetermined temperature during film formation. A drive shaft 61 is connected to the lower surface of the stage body 6, penetrating the lower wall of the vacuum chamber 1 while maintaining an airtight seal and protruding into the vacuum chamber 1. The stage body 6 is able to move up and down via the drive shaft 61 by a drive source 62 such as an air seal or a linear motor installed outside the vacuum chamber 1. As a result, the stage body 6 moves up and down between a substrate transfer position (shown in Figure 4(b)) where the substrate Sg is transferred at a distance from the target 2, and a substrate processing position (shown in Figures 3 and 4(a)) where film deposition is performed in close proximity to the target 2. Multiple through holes 63 are formed in the stage body 6, penetrating in the vertical direction. The diameter of each through hole 63 and the distance between each through hole 63 are set appropriately, taking into consideration the substrate size and the temperature distribution of the substrate Sg during film deposition.

[0026] Support rods 64 are inserted into each through-hole 63 with a gap between them. Each support rod 64 is made of a metal rod with relatively high mechanical strength and has a large-diameter portion 64a that is housed in the through-hole 63 with a gap between it and the substrate processing position, and a small-diameter portion 64b that extends downward from the large-diameter portion 64a. A cap body 64c made of a different material is attached to the upper end of each support rod 64. The cap body 64c is made of a molded resin such as polyimide. Although not specifically illustrated and explained, an upward-extending mounting hole is formed on the lower surface of the cap body 64c, and the cap body 64c is attached by fitting it from above into the other small-diameter portion formed at the upper end of each support rod 64. Guide members 65 are vertically attached to the stage body 6 so as to surround the lower edge of each through-hole 63.

[0027] The guide member 65 has a cylindrical member 65b of a predetermined length made of metal with relatively high mechanical strength, through which the small-diameter portion 64b of each support rod 64 is inserted. The upper surface of the cylindrical member 65b is provided with a cylindrical projection 65c that extends upward so as to surround the upper edge of the through hole 65a, and the projection 65c is fitted into the through hole 63 from below. As a result, when the stage body 6 moves upward relative to each support rod 64, the lower surface of the large-diameter portion 64a of each support rod 64 comes into contact with the upper surface of the projection 65c, locking each support rod 64 in place (restricting the downward movement of each support rod 64) and preventing each support rod 64 from falling out of each through hole 63. The length of the large-diameter portion 64a of each support rod 64 is appropriately set considering the amount of protrusion of each support rod 64 from the stage body 6 at the substrate transfer position and the thickness of the stage body 6. The diameters of the large-diameter portion 64a and the small-diameter portion 64b are set considering the diameters of the through-holes 63 and insertion holes 65a. Furthermore, a pair of upper and lower guide rollers 66, 66 are provided on the cylindrical member 65b to guide the relative vertical movement of each support rod 64 (specifically the small-diameter portion 64b).

[0028] A support plate 67 is placed on the inner surface of the lower wall of the vacuum chamber 1, and a regulating base 68 is placed on the upper surface of the support plate 67 so as to restrain the downward movement of each support rod 64 by contacting the lower end surface of each support rod 64, with the regulating base 68 also acting as a stopper member. Alternatively, the regulating base 68 can be placed directly on the inner surface of the lower wall of the vacuum chamber 1 without installing the support plate 67. Furthermore, a spacer member (not shown) may be detachably installed on the upper or lower surface of the regulating base 68 so as to change the amount of protrusion of each support rod 64 from the stage body 6 at the substrate transfer position.When a substrate Sg is placed on the upper surface of the stage body 6 at the substrate processing position and a film is deposited, a mask unit Um is placed inside the vacuum chamber 1 to cover the outer edge of the substrate Sg and restrict the film deposition area on the substrate Sg.

[0029] As shown in enlarged view in Figures 4(a) and (b), the mask unit Um has a first mask body 71 and a second mask body 72, each made of a metal material that is frame-shaped and resistant to thermal deformation. The second mask body 72 is attached to a support frame 17, which is provided on the inner surface of the side wall of the vacuum chamber 1 and corresponds to the substrate processing position. The first mask body 71 is installed on the flange portion 17a of the support frame 17 that extends inward into the vacuum chamber 1, with an insulator 17b interposed between them, so that the first mask body 71 is electrically floating. The tip portion 71 of the first mask body 71, located on the inner side of the vacuum chamber 1, is formed as an inclined surface whose upper surface continuously slopes downward toward the inside of the vacuum chamber 1 so as to suppress so-called mask blurring at the outer edge of the substrate. At the substrate processing position, the tip portion 71 is located directly above the outer edge of the substrate Sg with a vertical gap. Furthermore, a receiving recess (hereinafter referred to as the "first receiving recess 72") that is recessed vertically is formed on the lower surface of the first mask body 71, which is located outside the vacuum chamber 1 from the tip portion 71.

[0030] When a substrate Sg is placed on the upper surface of the stage body 6, a first protruding wall 69 is provided on the outer peripheral edge of the upper surface of the stage body 6, located outside the periphery of the substrate Sg. When the stage body 6 is moved upward to the substrate processing position, the first protruding wall 69 is received by the first receiving recess 72 of the first mask body 71 with a gap between them, and a labyrinth-like gap Gp1 is formed outside the periphery of the substrate Sg, where the first protruding wall 69 and the first receiving recess 72 interlock non-contact. The size of the gap Gp1 is appropriately set according to the sputtering conditions (target type, input power and sputtering time) and the thermal deformation (amount of thermal expansion) of the first mask body 71 and the second mask body 72 during film deposition. At this time, the size of the gap Gp1 can be changed by changing the stopping position of the stage body 6 at the substrate processing position.

[0031] When the first protruding wall 69 is formed on the stage body 6, sputtered particles that bounce off the first protruding wall 69 during film deposition may wrap around to the outer edge of the substrate Sg. At this time, because the amount of warping of the substrate during film deposition differs depending on the sputtering conditions, the outer edge of the substrate Sg and the upper surface of the stage body 6 may become fixed together via the wrapped sputtered particles, which could cause damage to the substrate during transport. Therefore, a frame-shaped support plate 6a of a predetermined thickness is provided on the upper surface of the stage body 6 to support the substrate Sg by contacting the portion of the substrate Sg inside the outer edge. This lifts the substrate Sg (especially the outer edge of the substrate) away from the upper surface of the stage body 6, thereby minimizing the adhesion between the outer edge of the substrate Sg and the upper surface of the stage body 6. Although the support plate 6a is used as an example of a support, it can also be configured by providing multiple support pins, for example.

[0032] A second protruding wall 73 is provided on the upper surface of the rear end portion of the first mask body 71, and correspondingly, a second receiving recess 74 is provided on the lower surface of the second mask body 72 to receive the second protruding wall 73 with a gap between them. When the first mask body 71 and the second mask body 72 are assembled, a labyrinth-like gap Gp2 is formed around the outer periphery of the substrate Sg, where the second protruding wall 73 and the second receiving recess 74 interlock non-contact. The tip portion of the second mask body 72, located on the inside side of the vacuum chamber 1, has an inclined surface on its upper surface that is inclined at the same angle as described above, covering the upper surface portion of the first mask body 71 other than the tip portion 71, thereby suppressing film formation as much as possible. Furthermore, the support frame 17 and the second mask body 72 installed thereon are provided with through holes 17c and 75 that penetrate vertically, and the through holes 17c and 75 constitute part of the exhaust path leading from the film deposition space 1a to the vacuum pump 13. In addition, a cylindrical wall portion (hereinafter referred to as the "lower cylindrical wall portion 76") is provided at a predetermined position on the upper surface of the second mask body 72, extending upward and with its upper end portion reaching the vicinity of the shield plate 4, so as to surround the periphery of the film deposition space 1a. In the second embodiment, the second mask body 72 constitutes another shield plate.

[0033] On the lower surface of the shield plate 4, as shown in an enlarged view in Figure 3, two upper cylindrical wall portions (hereinafter, one upper cylindrical wall portion located on the inner side of the vacuum chamber will be referred to as the "first wall portion 41," and the other cylindrical wall portion as the "second wall portion 42") are provided at different distances from the center of the target 2, extending downward for a predetermined length. In the second embodiment, the first wall portion 41 constitutes a cylindrical wall portion that extends downward for a predetermined length from a position close to the end of the target 2. When the shield plate 4 and the second mask body 72 are assembled, the upper end portion of the lower cylindrical wall portion 76 penetrates the gap between the first wall portion 41 and the second wall portion 42, forming a labyrinth-like gap Gp3 outside the periphery of the film deposition space 1a, in which the first and second wall portions 41, 42 and the lower cylindrical wall portion 76 interlock non-contact. The gap Gp3 also serves as an exhaust path leading from the film deposition space 1a to the vacuum pump 13. Therefore, the size of the gap GP3 and the lengths of the lower cylindrical wall portion 76, the first wall portion 41, and the second wall portion 42 are set appropriately in order to ensure a certain exhaust conductance, but it is preferable to set the area facing the lower cylindrical wall portion 76 to be larger for the first wall portion 41 than for the second wall portion 42.

[0034] Here, during film formation, sputtered particles directly adhere to the first wall portion 41 and the lower cylindrical wall portion 76, which allow direct viewing of the target 2, resulting in a relatively large amount of film deposition. Therefore, it is preferable that a peeling suppression treatment Sp is applied to at least the entire surface of the first wall portion 41 and the surface of the lower cylindrical wall portion 76 located on the inner side of the vacuum chamber 1 to suppress film peeling. Examples of peeling suppression treatment Sp include surface treatments that increase the surface area by forming fine irregularities on the surface (so-called AET treatment), as shown in the enlarged explanation in Figure 3, as well as known thermal spraying and blasting treatments. This reduces the frequency of replacement between the first wall portion 41 and the lower cylindrical wall portion 76. Such peeling suppression treatment may also be applied to the surface portion of the second mask body 72, which is located on the inner side of the vacuum chamber 1 than the lower cylindrical wall portion 76, and to the second wall portion 42. Furthermore, for example, considering cost considerations, thermal spraying may be performed in addition to AET treatment in the areas with the largest film deposition to effectively suppress film peeling, thermal spraying only may be performed in the areas with the next largest film deposition, and blasting only may be performed in the remaining areas. The film deposition on the substrate Sg will be described in detail below.

[0035] When depositing a film onto the substrate Sg, first, the stage body 6 of the substrate stage St is moved to the substrate transfer position (see also Figure 2(b)). Although not specifically illustrated and explained, at the substrate transfer position, the lower surface of the small-diameter portion 64b of each support rod 64 abuts against the upper surface of the regulating base 68, and each support rod 64 protrudes from the stage body 6 by a predetermined amount. Taking into account the deflection due to the weight of the substrate Sg, the amount of protrusion of each support rod 64 from the stage body 6 on the outer edge side of the substrate Sg may be increased. Then, the substrate Sg is transported into the vacuum chamber 1 by a transport robot through the substrate discharge port 18 (see Figure 1) opened in the side wall of the vacuum chamber 1, and the substrate is temporarily received so that it is supported by the upper end surfaces of each support rod 64. After the transport robot is moved away and the substrate discharge port 18 is closed, the inside of the vacuum chamber 1 is evacuated to a predetermined pressure, and the stage body 6 is moved upward relative to each support rod 64.

[0036] As the stage body 6 moves upward, the small-diameter portion 64b of each support rod 64 moves downward relative to the stage body 6, guided by a pair of upper and lower guide rollers 66, 66. When the lower surface of the large-diameter portion 64a contacts the upper surface of the projection portion 65c, each support rod 64 is locked in place, restricting its downward movement and preventing it from falling out of the through-holes 63. In this state, the lower surface of the small-diameter portion 64b of each support rod 64 is separated from the upper surface of the regulating base 68, and the large-diameter portion 64a, including the cap body 64c of each support rod 64, reaches a substrate processing position where it is completely immersed in the through-hole 63 (see Figure 1). At this time, the substrate Sg is placed in surface contact with the upper surface of the stage body 6, and the first protruding wall 69 penetrates the first receiving recess 72 of the first mask body 71, forming a labyrinth-like gap Gp1 around the outer periphery of the substrate Sg where the first protruding wall 69 and the first receiving recess 72 interlock in a non-contact manner. Then, a sputtering gas such as argon gas (which may contain reaction gases such as oxygen gas or nitrogen gas) is introduced into the vacuum chamber 1 in a vacuum atmosphere, and DC power with a negative potential, for example, is applied to the target 2 by the sputtering power supply 24. As a result, plasma is formed in the deposition space 1a, and the sputtering surface 21 of the target 2 is sputtered by ions of the sputtering gas in the plasma. Sputtered particles scattered from the target 2 according to a predetermined cosine law adhere to and accumulate on the lower surface of the substrate Sg through the first mask body 71, thereby forming a predetermined thin film. After film formation, the stage body 6 is moved down from the substrate processing position to the substrate transfer position.

[0037] According to the second embodiment described above, similar to the first embodiment, the inner surface of the first wall portion 41 functions as an anode during sputtering, thereby improving the in-plane uniformity of the film quality, such as the sheet resistance, when a molybdenum film is deposited on the upper surface of the substrate Sg. Furthermore, the sputtering apparatus can be miniaturized, and although sputtered particles scatter to various locations in the vacuum chamber other than the substrate Sg during sputtering of the target 2, or bounce and scatter further, the area around the target 2 and the deposition space 1a are surrounded by the upper cylindrical wall portions 41, 42 and the lower cylindrical wall portion 76 that form the gap Gp3 of the labyrinth structure, so the circling and passing of sputtered particles from the target 2 and bounced sputtered particles can be effectively suppressed. Furthermore, since the area of ​​the first wall portion 41 facing the lower cylindrical wall portion 76 is set to be larger than that of the second wall portion 42, sputtered particles attempting to circumvent the sputtering can be deflected as many times as possible by the opposing surfaces of the first wall portion 41 and the lower cylindrical wall portion 76, thereby more effectively suppressing the circumvention of sputtered particles. [Explanation of Symbols]

[0038] SM1, SM2…Magnetron sputtering apparatus, St…Substrate stage, Sg…Substrate, Um…Mask unit (mask body), 1…Vacuum chamber, 13…Vacuum pump, 17…Support frame (support part), 17c…Exhaust path, 2…Target, 3…Magnet unit, 4…Shield plate, 40…Upper cylindrical wall section (cylindrical wall section), 41…First wall section (component of the upper cylindrical wall section), 42…Second wall section (component of the upper cylindrical wall section) Elements) St1,6...stage body, 6a...support, 62...driving means, 63...through hole, 64...support rod, 69...first protruding wall, substrate 71...first mask body, 72...second mask body, 72...first receiving recess, 73...second protruding wall, 74...second receiving recess, D1...distance between target end and cylindrical wall portion, second receiving recess, Gp, Gp1, Gp2, Gp3...gaps in labyrinth structure, Sp...peeling suppression treatment.

Claims

1. A magnetron sputtering apparatus having a vacuum chamber in which a target and a substrate are arranged facing each other, a shield plate arranged to surround the target and function as an anode during sputtering of the target, and a magnet unit that applies a leakage magnetic field to the film deposition space between the target and the substrate, A magnetron sputtering apparatus characterized by having a cylindrical wall portion extending downward for a predetermined length from a position close to the edge of the target on the lower surface of the shield plate, which is in the direction from the target to the substrate.

2. A magnetron sputtering apparatus comprising another shield plate arranged around the substrate in the vacuum chamber, wherein the cylindrical wall portion is an upper cylindrical wall portion, and a lower cylindrical wall portion is provided on the upper surface of the other shield, having a length such that its upper end overlaps with the lower end of the upper cylindrical wall portion with a gap between them.

3. The magnetron sputtering apparatus according to claim 2, characterized in that the lower cylindrical wall portion is designated as the first wall portion, a second wall portion is further provided on the upper surface of the other shield plate positioned around the first wall portion, and the upper end of the upper cylindrical wall portion enters the gap between the first wall portion and the second wall portion, thereby forming a labyrinth structure gap on the outer periphery of the film deposition space in which the lower cylindrical wall portion, the first wall portion and the second wall portion interlock in a non-contact manner.

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