Film forming apparatus, processing condition determining method, and film forming method

Abstract

To provide a coat forming apparatus with which in-plane uniformity of a coat is improved when the coat is formed by magneto sputtering.SOLUTION: A coat forming apparatus comprises: a substrate supporting part 14, a holder 20a holding a target 20, a magnet unit 23 having a magnet, a first moving mechanism 15 for periodically moving the substrate supporting part 14, a second moving mechanism 24 for periodically moving the magnet unit 23 to the target held by the holder 20a, and a control unit U. The control unit U is so configured to control the first moving mechanism 15 and the second moving mechanism 24 in a manner where: phases of the periodical movement of the substrate supporting part 14 are identical between start of coat formation and finish of coat formation; phases of the periodical movement of the magnet unit 23 are identical between start of coat formation and finish of coat formation; and a phase of the periodical movement of the substrate supporting part 14 is not identical with a phase of the periodical movement of the magnet unit 23 during coat formation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a film forming apparatus, a process condition determining method, and a film forming method. [Background technology]

[0002] Patent Document 1 discloses a sputtering apparatus having a sputtering cathode for supporting a target and a substrate support holder for supporting a substrate. In this sputtering apparatus, the sputtering cathode and the substrate support holder are arranged so that, among perpendicular lines to a plane including the substrate surface on which a film is to be formed, a perpendicular line passing through the center point of the target and a perpendicular line passing through the center point of the substrate do not coincide, and the substrate support holder is rotatable around a rotation axis perpendicular to the substrate surface on which a film is to be formed. In addition, in this sputtering apparatus, when the total number of rotations of the substrate support holder during the deposition time T (seconds) of sputtered particles on the substrate surface on which a film is to be formed is X, the following equation is satisfied: X=N+α (where N is the total number of revolutions, which is a positive integer, and α is the fractional number of revolutions, which is a positive pure decimal.) By inputting the values ​​of the total integer rotation number N, the fractional rotation number α, and the deposition time T, the rotation speed V (rps) of the substrate support holder can be calculated as follows: V T = N + α The control unit controls the temperature so that the following condition is satisfied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2009 / 60911 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure improves the in-plane uniformity of film thickness when forming a film by magnetron sputtering. [Means for solving the problem]

[0005] One aspect of the present disclosure is a film formation apparatus for forming a film on a substrate by magnetron sputtering, the film formation apparatus including: a substrate support part for supporting a substrate; a holder for holding a target that emits sputter particles so that the target faces the substrate support part; a magnet unit provided on the opposite side of the holder from the substrate support part and having a magnet; a first movement mechanism for periodically moving the substrate support part; a second movement mechanism for periodically moving the magnet unit relative to the target held by the holder; and a control unit, the control unit being configured to determine a total number of movements Nw of the substrate support part during film formation and a number of times the magnet unit moves during film formation. the first moving mechanism and the second moving mechanism are controlled to satisfy the following conditions: the total number of movements Nm of the substrate support unit and the total number of movements Nw of the magnet unit are different natural numbers, the total number of movements Nm is not an integer multiple of the total number of movements Nw, and the total number of movements Nw is not an integer multiple of the total number of movements Nm; and when there are a plurality of numbers of movements per unit time of the substrate support unit that satisfy the above condition and another condition that the numbers of movements per unit time of the substrate support unit and the magnet unit are each within a predetermined range, the first moving mechanism is controlled so that the substrate support unit moves at the largest number of movements per unit time. The apparatus further includes a first shield member and a second shield member that form a processing space, the first shield member having a hole that exposes the substrate supported by the substrate support part to the processing space, the second shield member having an opening through which the sputtered particles from the target held by the holder are supplied to the processing space, and the apparatus further includes a rotation mechanism that rotates the second shield member, and the rotation mechanism switches a portion of the second shield member that faces the target held by the holder between the opening and a portion where the opening is not formed. . [Effects of the Invention]

[0006] According to the present disclosure, it is possible to improve the in-plane uniformity of film thickness when forming a film by magnetron sputtering. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a longitudinal sectional view showing an outline of the configuration of a film forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining the configuration around the cathode. [Figure 3] FIG. 2 is a perspective view of a magnet unit. [Figure 4]10 is a diagram showing the relationship between the position of a magnet unit relative to a target and the size of an area of ​​the target exposed to plasma. FIG. [Figure 5] 10 is a diagram showing the relationship between the position of a magnet unit relative to a target and the size of an area of ​​the target exposed to plasma. FIG. [Figure 6] 10A and 10B are diagrams for explaining a method for determining the total number of rotations of the mounting table and the total number of oscillations of the magnet unit during film formation. [Figure 7] 10A and 10B are diagrams for explaining a method for determining the total number of rotations of the mounting table and the total number of oscillations of the magnet unit during film formation. [Figure 8] FIG. 10 is a diagram showing the distribution of film thickness within the wafer surface in a comparative example. [Figure 9] FIG. 10 is a diagram showing the distribution of film thickness within the surface of a wafer W in an example. DETAILED DESCRIPTION OF THE INVENTION

[0008] 2. Description of the Related Art In a manufacturing process for semiconductor devices and the like, a film formation process is performed to form a desired film of metal or the like on a substrate such as a semiconductor wafer (hereinafter referred to as a "wafer"), for example, by sputtering.

[0009] A film formation apparatus that forms a film by sputtering is provided with, for example, a substrate support that supports a substrate, and a cathode that holds the target that emits sputter particles in front of it so that the target faces the substrate support.

[0010] In cases where the target is held by the cathode so as to be non-parallel to the substrate, the substrate support may be configured to be rotatable, and the substrate supported by the substrate support may be configured to rotate during film formation. This is to suppress variations in the thickness of the film formed on the substrate by sputtering within the substrate surface. In Patent Document 1, the total rotation of the substrate support holder is set to a predetermined value based on the deposition time of the sputtered particles and the rotation speed of the substrate support holder, thereby ensuring uniformity in the deposition amount, i.e., film thickness.

[0011] Furthermore, when magnetron sputtering is employed as the sputtering method, a magnet unit having a magnet and smaller than the target is provided to effectively utilize the entire target, and this magnet unit is configured to be swingable or rotatable relative to the cathode. However, in the case of such magnetron sputtering, simply adjusting the total number of rotations of the substrate support unit as in Patent Document 1 may not provide sufficient film thickness uniformity.

[0012] Therefore, the technology according to the present disclosure improves the in-plane uniformity of film thickness when forming a film by magnetron sputtering.

[0013] Hereinafter, a film forming apparatus, a process condition determination method, and a film forming method according to the present embodiment will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0014] <Film forming equipment> Fig. 1 is a vertical cross-sectional view showing the outline of the configuration of a film forming apparatus 1 according to this embodiment, Fig. 2 is a diagram for explaining the configuration around a cathode described later, and Fig. 3 is a perspective view of a magnet unit described later.

[0015] The film forming apparatus 1 in Figure 1 forms a film on a substrate by magnetron sputtering, and specifically, forms a film for a magnetic tunnel junction (MTJ) element (e.g., a Ta film) on a wafer W as a substrate by magnetron sputtering.

[0016] The film forming apparatus 1 includes a processing vessel 10. The processing vessel 10 is configured to be depressurized, accommodates a wafer W, is made of, for example, aluminum, and is connected to a ground potential. An exhaust device 11 is connected to the bottom of the processing vessel 10 to depressurize a space K1 within the processing vessel 10. The exhaust device 11 includes a vacuum pump (not shown) and the like, and is connected to the processing vessel 10 via, for example, an APC valve 12.

[0017] In addition, a loading / unloading port 13 for the wafer W is formed in the side wall on one side (the positive side in the X direction in the figure) of the processing vessel 10, and a gate valve 13a for opening and closing the loading / unloading port 13 is provided in the loading / unloading port 13.

[0018] A mounting table 14 serving as a substrate support for supporting a wafer W is provided within the processing vessel 10. Specifically, the wafer W is placed horizontally on the mounting table 14 so as to face a processing space K2 defined by a shield 30 (described below). The mounting table 14 supports the wafer W thus placed. The mounting table 14 includes an electrostatic chuck 14a, a heater 14b, and a base 14c.

[0019] The electrostatic chuck 14a has, for example, a dielectric film and an electrode provided as an inner layer of the dielectric film, and is provided on a base portion 14c. A DC power supply (not shown) is connected to the electrode of the electrostatic chuck 14a. The wafer W placed on the electrostatic chuck 14a is attracted and held by the electrostatic chuck 14a by an electrostatic attraction force generated by applying a DC voltage from the DC power supply to the electrode.

[0020] The heater 14b heats the wafer W supported on the mounting table 14. The heater 14b heats the mounting table 14 (specifically, the electrostatic chuck 14a), thereby heating the wafer W supported on the mounting table (specifically, the electrostatic chuck 14a). The heater 14b may be, for example, a resistance heater, and is provided in the electrostatic chuck 14a.

[0021] The base portion 14c is formed in a disk shape using aluminum, for example. Depending on the type of the heater 14b, the heater 14b may be provided on the base portion 14c.

[0022] The mounting table 14 may be provided with a cooling mechanism for cooling the wafer W mounted on the mounting table 14.

[0023] Furthermore, the mounting table 14 is connected to a rotation / movement mechanism 15 serving as a first movement mechanism. The rotation / movement mechanism 15 periodically moves the mounting table 14, and in this embodiment, rotates and moves the mounting table 14. Specifically, the rotation / movement mechanism 15 rotates the mounting table 14 about an axis AX that passes through the center of the upper surface of the mounting table 14 and is perpendicular to the upper surface. The rotation / movement mechanism 15 can also move the mounting table 14 up and down. The rotation / movement mechanism 15 has, for example, a support shaft 15a and a drive unit 15b.

[0024] The support shaft 15a extends in the vertical direction, for example, penetrating the bottom wall of the processing vessel 10. A sealing member SL1 is provided between the support shaft 15a and the bottom wall of the processing vessel 10. The sealing member SL1 is a member, such as a magnetic fluid seal, that seals the space between the bottom wall of the processing vessel 10 and the support shaft 15a so that the support shaft 15a can rotate and move up and down. The upper end of the support shaft 15a is connected to the center of the lower surface of the mounting table 14, and the lower end is connected to the drive unit 15b.

[0025] The drive unit 15b has a drive source such as a motor, and generates a drive force for rotating and moving the support shaft 15a up and down. The drive force generated by the drive unit 15b causes the support shaft 15a to rotate about the axis AX, which in turn causes the mounting table 14 to rotate about the axis AX. The drive force generated by the drive unit 15b causes the support shaft 15a to move up and down, which in turn causes the mounting table 14 to move up and down.

[0026] The number of rotations per unit time (hereinafter referred to as the rotation speed of the mounting table 14) Vw by the rotation / movement mechanism 15 is, for example, 60 to 120 times per minute (i.e., 60 rpm to 120 rpm). If the rotation speed Vw of the mounting table 14 is less than 60 rpm, the total number of rotations of the wafer W required to achieve a uniform film thickness distribution cannot be obtained. Furthermore, if the rotation speed Vw of the mounting table 14 is greater than 120 rpm, the load on the drive unit 15b of the rotation / movement mechanism 15 and the like increases, shortening the life of the rotation / movement mechanism 15.

[0027] The rotation / movement mechanism 15 (specifically, the drive unit 15b) is controlled by a control unit U, which will be described later.

[0028] A holder 20a made of a conductive material is provided diagonally above the mounting table 14. The holder 20a holds the target 20, which is made of, for example, Ta and emits sputter particles. The holder 20a holds the target 20 so that the target 20 is positioned within the processing vessel 10. The holder 20a is attached to the ceiling of the processing vessel 10. A through-hole is formed in the processing vessel 10 at the mounting position of the holder 20a. An insulating member 10a is provided on the inner wall surface of the processing vessel 10 to surround the through-hole. The holder 20a is attached to the processing vessel 10 via the insulating member 10a so as to close the through-hole.

[0029] The holder 20a holds the target 20 in front so that the target 20 faces the mounting table 14. Specifically, the holder 20a holds the target 20 so that the target 20 faces the mounting table 14 and is tilted with respect to the upper surface of the mounting table 14, i.e., the surface of the wafer W mounted on the upper surface.

[0030] The target 20 is formed, for example, in a rectangular shape in a plan view. When the target 20 is held by the holder 20a, its major axis direction extends in the depth direction of the apparatus (Y direction in FIG. 1). The length of the target 20 in the depth direction of the apparatus (Y direction in FIG. 1) is greater than, for example, the diameter of the wafer W on which a film is to be formed. When the diameter of the wafer W on which a film is to be formed is 300 mm, the length of the target 20 in the depth direction of the apparatus (Y direction in FIG. 1) is, for example, 400 to 500 mm. The length of the target 20 in the direction (X' direction in the figure) perpendicular to the depth direction of the apparatus (Y direction in FIG. 1) is, for example, 150 to 200 mm.

[0031] Further, a power source 21 is connected to the holder 20a, and a negative DC voltage is applied from the power source 21. Instead of the negative DC voltage, an AC voltage may be applied. 2, the holder 20a is provided with a shield 22 for the purpose of preventing other parts from being contaminated by sputtered particles from the target 20 held by the holder 20a. The shield 22 is provided, for example, so as to cover the outer periphery of the target 20 held by the holder 20a.

[0032] Furthermore, a magnet unit 23 is provided on the opposite side of the holder 20a from the mounting table 14, i.e., the rear side, outside the processing vessel 10. The magnet unit 23 generates a magnetic field that leaks toward the front side of the target 20 held by the holder 20a. For example, as shown in FIG. 3, the magnet unit 23 is configured by arranging a rectangular parallelepiped central magnet 102 and an outer peripheral magnet 103 that is annular in plan view on a flat plate-shaped yoke 101. The central magnet 102 is provided along the longitudinal direction of the yoke 101, and the outer peripheral magnet 103 is provided to surround the four sides of the central magnet 102 in plan view. The central magnet 102 and the outer peripheral magnet 103 are magnetized in opposite directions to each other in a direction perpendicular to the surface of the yoke 101 facing the central magnet 102.

[0033] As shown in FIG. 1, the magnet unit 23 is connected to a moving mechanism 24 serving as a second moving mechanism. The moving mechanism 24 periodically moves the magnet unit 23. In this embodiment, the moving mechanism 24 causes the magnet unit 23 to oscillate, i.e., to reciprocate, along the back surface of the holder 20a in the device depth direction (the Y direction in FIGS. 1 and 3). In other words, the moving mechanism 24 moves the magnet unit 23 along the back surface of the holder 20a in the positive direction of the feed depth direction (the positive Y direction in FIGS. 1 and 3), and also in the negative direction of the device depth direction (the negative Y direction in FIGS. 1 and 3).

[0034] The movement mechanism 24 has, for example, a rail 24a extending along the depth direction of the apparatus (the Y direction in FIGS. 1 and 3 ) and a drive unit 24b including a drive source such as a motor. The drive unit 24b generates a driving force to move the magnet unit 23 along the rail 24a in the depth direction of the apparatus (the Y direction in FIGS. 1 and 3 ). More specifically, the drive force generated by the drive unit 24b moves the magnet unit 23 so as to perform a reciprocating motion between one end of the target 20 in the depth direction of the apparatus (the negative end in the Y direction in FIGS. 1 and 3 ) and the other end (the positive end in the Y direction in FIGS. 1 and 3 ). This prevents the target 20 from being consumed locally, making it possible to utilize substantially the entire target 20.

[0035] In this specification, the "number of oscillations" of the magnet unit 23 is counted, for example, as one oscillation when the target 20 moves from the negative end in the device depth direction to the positive end in the depth direction, and as one oscillation when the target 20 moves from the positive end in the device depth direction to the negative end in the depth direction. Therefore, when the magnet unit 23 makes one reciprocating motion, the "number of oscillations" of the magnet unit 23 is two.

[0036] The number of times the magnet unit 23 is oscillated per unit time by the moving mechanism 24 (hereinafter referred to as the oscillation speed of the magnet unit 23) is, for example, 30 to 120 times / minute. If the oscillation speed Vm of the magnet unit 23 is less than 30 times / minute, it is not possible to sufficiently prevent the target 20 from being locally consumed. If the oscillation speed Vm of the magnet unit 23 is greater than 120 times / minute, the load on the drive unit 24b of the moving mechanism 24 and the like increases, shortening the life of the moving mechanism 24.

[0037] The moving mechanism 24 (specifically, the driving unit 24b) is controlled by a control unit U, which will be described later.

[0038] Furthermore, the film forming apparatus 1 includes a shield unit 30 that forms a processing space K2 within the processing chamber 10. The shield unit 30 is provided within the processing chamber 10.

[0039] The shielding section 30 has a first shielding member 31 and a second shielding member 32. The first shielding member 31 and the second shielding member 32 are made of, for example, aluminum.

[0040] The first shield member 31 is a pot-shaped member with an open top and a hole 31a in the bottom surface for exposing the processing space K2 to the wafer W placed on the mounting table 14. The first shield member 31 is supported in the processing chamber 10 via, for example, a support member (not shown).

[0041] The second shield member 32 is a cover member that closes the opening at the top of the first shield member 31, and is formed so that its central portion in a plan view protrudes upward. The second shield member 32 has an opening 32a. Sputtered particles from the target 20 held by the holder 20a are supplied to the processing space K2 through the opening 32a.

[0042] One end of a rotating shaft 33 is connected to the center of the second shield member 32. The central axis of the rotating shaft 33 substantially coincides with the axis AX. The rotating shaft 33 extends to the outside of the processing vessel 10, and the other end of the rotating shaft 33 is connected to a rotating mechanism 34. The rotating mechanism 34 rotates the rotating shaft 33 about the axis AX. The rotating mechanism 34 has a driving unit (not shown) including a driving source such as a motor that generates a driving force for rotating the rotating shaft 33.

[0043] By rotating the second shield member 32, the opening 32a of the second shield member 32 can be made to face the target 20 held by the holder 20a, or the portion of the second shield member 32 where the opening 32a is not formed can be made to face the target 20.

[0044] The film forming apparatus 1 also includes a gas supply unit (not shown) that supplies gas into the processing vessel 10. The gas supply unit includes, for example, a gas source, a flow rate controller such as a mass flow controller, and a gas introduction unit. The gas source stores a gas (e.g., Ar gas) that is excited in the processing vessel 10. The gas source is connected to the gas introduction unit via the flow rate controller. The gas introduction unit is a member that introduces gas from the gas source into the processing vessel 10.

[0045] When gas is supplied from the gas supply unit and power is supplied to the target 20 by the power supply 21, the gas supplied into the processing vessel 10 is excited. In addition, a magnetic field is generated near the front of the target 20 by the magnet unit 23, and plasma is concentrated near the front of the target 20. Then, positive ions in the plasma collide with the target 20, causing materials constituting the target 20 to be emitted from the target 20 as sputtered particles. As a result, a desired film is formed on the wafer W.

[0046] As shown in FIG. 1, the film forming apparatus 1 further includes a control unit U. The control unit U is configured by, for example, a computer including a CPU, a memory, and the like, and has a program storage unit (not shown). The program storage unit stores a program for controlling the driving unit 15b, the power supply 21, the driving unit 24b, and the like to realize the film forming process described below in the film forming apparatus 1. The program storage unit also stores a program for determining processing conditions for film formation. The program may be recorded on a computer-readable storage medium and installed into the control unit U from the storage medium. The storage medium may be temporary or non-temporary. Some or all of the program may be realized by dedicated hardware (circuit board).

[0047] <Total Number of Rotations Nw of the Mounting Table 14 and Total Number of Oscillations Nm of the Magnet Unit 23 During Film Formation> In cases where the target 20 is tilted relative to the upper surface of the mounting table 14, i.e., the surface of the wafer W mounted on the upper surface, as described above, the film thickness may become non-uniform within the surface of the wafer W when the film is formed on the wafer W. This is caused by, for example, the fact that the distance to the target 20 varies depending on the region on the surface of the wafer W. To eliminate this in-plane uniformity in the film thickness, the mounting table 14 on which the wafer W is mounted is rotated during film formation. However, when the magnet unit 23 is used, even if the mounting table 14 is rotated, the in-plane uniformity of the film thickness may be insufficient for the following reasons.

[0048] That is, to effectively utilize the target 20, the magnet unit 23 is configured to oscillate with respect to the target 20 so that the magnetic field generated by the magnet unit 23 covers the entire width of the target 20. Furthermore, the area of ​​the target 20 exposed to the plasma P varies depending on whether the magnet unit 23 is positioned at a portion facing the center of the target 20 in the oscillating direction as shown in FIG. 4 or at a portion facing an end of the target 20 in the oscillating direction as shown in FIG. 5. Therefore, the amount of sputtered particles emitted from the target 20 also varies, and the amount of thin film deposited on the wafer W per unit time (i.e., the deposition rate of the thin film on the wafer W) also varies. For example, if the magnet unit 23 is positioned at the center of the target 20 multiple times during film formation, depending on the relationship between the rotation speed Vw of the mounting table 14 and the oscillation speed Vm of the target 20, the orientation (position in the rotational direction) of the wafer W on the mounting table 14 at the time the magnet unit 23 is positioned at the center of the target 20 may be the same each time. In this case, even if the mounting table 14 is rotated during film formation, the film thickness distribution within the surface of the wafer W will be uneven.

[0049] In consideration of this point, in this embodiment, the control unit U controls the driving units 15b and 24b so as to satisfy the following conditions (1) to (3) during film formation. (1) The phase of the rotational movement of the mounting table 14 (specifically, the position in the rotational direction of the mounting table 14, that is, the orientation of the mounting table 14) is the same at the start and end of film formation. (2) The phase of the oscillation of the magnet unit 23 coincides at the start and end of film formation. (3) The phase of the rotational movement of the mounting table 14 and the phase of the oscillation of the magnet unit 23 do not match during film formation.

[0050] Satisfying the above condition (1) means that the total number of rotations Nw of the mounting table 14 during film formation is a natural number. This allows the length of time that each region on the surface of the wafer W on the mounting table 14 is closest to the target 20 to be equal for each region, thereby making it possible to uniform the thickness of the film formed across the wafer surface.

[0051] Satisfying the above condition (2) means that the total number of oscillations Nm of the magnet unit 23 during film formation is a natural number. This makes it possible to make the consumption of the target 20 uniform across the surface of the target 20.

[0052] Satisfying the above conditions (1) to (3) means that the total number of oscillations Nm is not an integer multiple of the total number of rotations Nw, and the total number of rotations Nw is not an integer multiple of the total number of oscillations Nm. This allows the orientation of the wafer W on the mounting table 14 to be different each time the magnet unit 23 is positioned at the center of the target 20, even if the magnet unit 23 is positioned at the center of the target 20 multiple times during film formation. In other words, when the magnet unit 23 is positioned at the center of the target 20, the position A at which the thin film is primarily deposited can be arranged at multiple positions (e.g., every 30°) within the plane of the wafer W as shown in FIG. 7, rather than at a single position within the plane of the wafer W as shown in FIG. 6. This prevents localized film thickness variations and improves film thickness uniformity within the plane of the wafer W.

[0053] <How to determine processing conditions> Next, an example of a method for determining the processing conditions for film formation by magnetron sputtering using the film formation apparatus 1 will be described, specifically, an example of a method for determining the processing conditions for the rotation of the mounting table 14 and the oscillation of the magnet unit 23 during film formation.

[0054] In this determination method, for example, the control unit U determines the processing conditions related to the rotation of the mounting table 14 and the oscillation of the magnet unit 23 during film formation so that the above conditions (1) to (3) are satisfied. Specifically, the processing conditions are as follows.

[0055] (Step S1: Determining the film formation time) For example, first, a target film thickness value is input to the control unit U by an operator or the like via an input device such as a keyboard, and the control unit U determines the film formation time T, i.e., the deposition time T, from the target film thickness value and the film formation rate, i.e., the thin film deposition rate, by the film formation apparatus 1, which has been acquired in advance.

[0056] (Step S2: Determining the total number of rotations Nw and the rotation speed Vw of the mounting table 14) Next, the control unit U determines the total number of rotations Nw of the mounting table 14 during film formation and the rotation speed Vw of the mounting table 14. Specifically, the control unit U determines the rotation speed Vw of the mounting table 14 from the range of 60 rpm to 120 rpm based on the film formation time T determined in step S1 so that the total number of rotations Nw of the mounting table 14 during film formation is a natural number.

[0057] (Step S3: Determining the total number of oscillations Nm and oscillation speed Vm of the magnet unit 23) Then, the control unit U determines the total number of oscillations Nm of the magnet unit 23 during film formation and the oscillation speed Vm of the magnet unit 23. Specifically, the oscillation speed Vm of the magnet unit 23 is determined from the range of 30 oscillations / minute to 120 oscillations / minute based on the film formation time T determined in step S1 so that the total number of oscillations Nm of the magnet unit 23 during film formation is a natural number that satisfies the above (3). In other words, Nm = Nw ± n (n is any natural number) The control unit U determines the oscillation speed Vm of the magnet unit 23 from the range of 30 times / minute to 120 times / minute so that the above condition is satisfied and Nm / Nw and Nw / Nm are not integers.

[0058] In addition, in steps S2 and S3, (1) Nm = Nw ± n (Nm and Nw are natural numbers, and n is any natural number) (2) Nm / Nw and Nw / Nm are not integers. (3) The rotation speed Vw of the mounting table 14 is in the range of 60 rpm to 120 rpm. (4) The oscillation speed Vm of the magnet unit 23 is in the range of 30 times / minute to 120 times / minute. If there are multiple rotation speeds Vw of the mounting table 14 that satisfy the above condition, the highest rotation speed Vw is selected in order to suppress variations in film formation. Similarly, when there are multiple oscillation speeds Vm of the magnet unit 23 for the rotation speed Vw of the mounting table 14 that has been determined / selected, the largest oscillation speed Vm is selected.

[0059] <Film formation process> Next, a description will be given of an example of a film formation process using the film formation apparatus 1. The following process is performed under the control of the control unit U.

[0060] (S11: Delivery) First, the wafer W is loaded into the processing chamber 10. Specifically, the gate valve 13a is opened, and a transfer mechanism (not shown) holding the wafer W is inserted into the processing vessel 10 through the transfer port 13 from a transfer chamber (not shown) in a vacuum atmosphere adjacent to the processing vessel 10, which is adjusted to a desired pressure by the exhaust device 11. At this time, the pressure in the processing vessel 10 and the transfer chamber is, for example, 10 -7 Torr~10 -9Torr. Next, the wafer W is transferred from the transfer mechanism onto the raised support pins (not shown), after which the transfer mechanism is removed from the processing vessel 10, and the gate valve 13a is closed. At the same time, the support pins are lowered, and the wafer W is placed on the mounting table 14 and is attracted and held by the electrostatic attraction force of the electrostatic chuck 14a. The mounting table 14 is also raised, and the wafer W moves to a position directly below the hole 31a in the shield portion 30.

[0061] (S12: Rotation of the mounting table 14) Next, the rotation / movement mechanism 15 is controlled so that the mounting table 14 rotates at the rotation speed Vw determined in the above-mentioned step S2 or the like.

[0062] (Step S13: Swinging the magnet unit 23) Furthermore, the moving mechanism 24 is controlled so that the magnet unit 23 oscillates at the oscillation speed Vm determined in the above-mentioned step S3 and the like.

[0063] (Step S14: Film formation) Subsequently, a desired film is formed on the wafer W by magnetron sputtering for the film formation time T determined in the above-mentioned step S1. Specifically, for example, Ar gas is supplied into the processing vessel 10 from a gas supply unit (not shown). Furthermore, power is supplied to the target 20 from a power supply 21. The power from the power supply 21 ionizes the Ar gas in the processing vessel 10, and electrons generated by the ionization drift due to a magnetic field (i.e., a leakage magnetic field) formed in front of the target 20 by the magnet unit 23, generating high-density plasma. The surface of the target 20 is sputtered by the Ar ions generated in the plasma, and the sputtered particles are deposited on the wafer W, forming a thin film. After the film formation time T determined in step S1 described above has elapsed since the start of power supply from the power supply 21, the power supply is stopped, the gas supply from the gas supply unit (not shown) is also stopped, and the rotation of the mounting table 14 and the oscillation of the magnet unit 23 are also stopped.

[0064] (Step S15: Carry out) Thereafter, the wafer W is unloaded from the processing chamber 10. Specifically, the wafer W is unloaded from the processing chamber 10 by performing the reverse operation of the loading operation in step S11. Then, the process returns to the above-mentioned loading step, and the next wafer W to be subjected to film formation is processed in the same manner.

[0065] <Major Effects of This Embodiment> As described above, according to this embodiment, when forming a film by magnetron sputtering, it is possible to suppress the occurrence of localized film thickness unevenness, and to improve the film thickness uniformity within the surface of the wafer W. [Example]

[0066] 8 and 9 are diagrams showing the film thickness distribution within the surface of the wafer W in the comparative example and the example, respectively. In the comparative example and the example, a target made of Ta was used as the target 20, and film formation was performed by magnetron sputtering at a film formation rate of 0.125 nm / s with a target film thickness of 1 nm. In other words, the film formation time T was 8 seconds.

[0067] In the comparative example and the example, the total number of rotations Nw of the mounting table 14 was set to 8, and the rotation speed of the mounting table 14 was set to 60 rpm, which is (Nw / T)×60 (Nw is 8 times, T is 8 seconds).

[0068] In the embodiment, the total number of oscillations Nm of the magnet unit 23 is set to 9, that is, Nm=Nw+1 (Nw is 8), so as to satisfy the condition that neither Nm / Nw nor Nw / Nm is an integer, and the phase of the rotational movement of the mounting table 14 and the phase of the oscillation of the magnet unit 23 do not coincide during film formation. On the other hand, in the comparative example, the total number of oscillations Nm of the magnet unit 23 is set to 8, Nm=Nw (Nw is 8), so as not to satisfy the condition that both Nm / Nw and Nw / Nm are not integers, and the phase of the rotational movement of the mounting table 14 and the phase of the oscillation of the magnet unit 23 are matched during film formation.

[0069] 8, in the comparative example, the phase of the rotational motion of the mounting table 14 and the phase of the oscillation of the magnet unit 23 coincided during film formation, resulting in extremely thick portions of the Ta film and non-uniform thickness within the surface of the wafer W. In addition, in the comparative example, the coefficient of variation (CV) of the film thickness, calculated by dividing the standard deviation of the film thickness by the average film thickness, was 2.0%.

[0070] On the other hand, in the example, there were no extremely thick portions of the Ta film compared to the comparative example, as shown in Figure 9. Furthermore, in the example, the coefficient of variation of the film thickness was 0.6%.

[0071] From the above results, it can be seen that by using the method disclosed herein, it is possible to form a thin film on the wafer W with a film thickness distribution having a coefficient of variation of 1% or less, even when magnet sputtering is performed while the magnet unit 23 is oscillating.

[0072] <Modification> In the above example, the total number of rotations Nw and the rotation speed Vw of the mounting table 14 are determined first, and then the total number of oscillations Nm and the oscillation speed Vm of the magnet unit 23 are determined. However, the total number of oscillations Nm and the oscillation speed Vm of the magnet unit 23 may be determined first, and then the total number of rotations Nw and the rotation speed Vw of the mounting table 14 may be determined later. Specifically, the control unit U may first determine the oscillation speed Vm of the magnet unit 23 from within a predetermined range based on the film formation time T so that the total number of oscillations Nm of the magnet unit 23 is a natural number. Then, the control unit U may determine the rotation speed Vw of the mounting table 14 from within a predetermined range based on the film formation time T so that the total number of rotations Nw of the mounting table 14 during film formation is a natural number that satisfies the above condition (3).

[0073] In the above example, the mounting table 14 is rotated, but the manner of periodic movement of the mounting table 14 is not limited to this. For example, the mounting table 14 may be swung in a predetermined direction, such as the horizontal direction, similar to the magnet unit 23. In this case, the technology according to the present disclosure can also be applied.

[0074] Furthermore, in the above example, the magnet unit 23 is swung, but the manner of periodic movement of the magnet unit 23 is not limited to this. For example, when the target 20 is circular in plan view, the magnet unit 23 may be rotated around the central axis of the target 20 along the back surface of the holder 20a. Alternatively, the magnet unit 23 may be moved around the central axis of the target 20 along the back surface of the holder 20a so as to trace a rectangular trajectory. The technology according to the present disclosure can be applied to these cases as well.

[0075] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0076] 1 Film deposition equipment 14 Mounting table 15 Rotation and movement mechanism 20 Target 20a holder 23 Magnet unit 24 Moving mechanism 102 central magnet 103 Periphery magnet Nm Total number of oscillations Nw total number of rotations T Film deposition time U control section W wafer

Claims

1. A film forming apparatus for forming a film on a substrate by magnetron sputtering, a substrate support portion that supports a substrate; a holder that holds the target, which emits sputter particles, so that the target faces the substrate support; a magnet unit provided on the opposite side of the holder from the substrate support portion and having a magnet; a first moving mechanism that periodically moves the substrate support; a second moving mechanism that periodically moves the magnet unit relative to the target held by the holder; a control unit; The control unit controlling the first moving mechanism and the second moving mechanism so as to satisfy the following conditions: a total number of movements Nw of the substrate support part during film formation and a total number of movements Nm of the magnet unit during film formation are different natural numbers, the total number of movements Nm is not an integer multiple of the total number of movements Nw, and the total number of movements Nw is not an integer multiple of the total number of movements Nm; when there are a plurality of numbers of movements per unit time of the substrate support unit that satisfy the above condition and another condition that the numbers of movements per unit time of the substrate support unit and the magnet unit each fall within a predetermined range, the first movement mechanism is controlled so that the substrate support unit moves at the largest number of movements per unit time, a first shield member and a second shield member that define a processing space; the first shield member has a hole through which the substrate supported by the substrate support portion is exposed to the processing space; the second shield member has an opening; the sputtered particles from the target held by the holder are supplied to the processing space through the opening; a rotation mechanism for rotating the second shield member; a film forming apparatus, wherein the rotation mechanism switches a portion of the second shield member facing the target held by the holder between the opening and a portion where the opening is not formed.

2. 2. The film deposition apparatus according to claim 1, wherein the predetermined range for the number of movements of the substrate support part per unit time is 60 to 120 times per minute.

3. The film forming apparatus of claim 1 or 2, wherein the control unit is configured to control the second movement mechanism so that the magnet unit moves at the largest number of movements per unit time when there are multiple numbers of movements per unit time of the magnet unit that satisfy the condition and the other condition.

4. 4. The film deposition apparatus according to claim 3, wherein the predetermined range for the number of movements of the substrate support part per unit time is 30 to 120 times per minute.

5. A film formation method for forming a film on a substrate by magnetron sputtering using a film formation apparatus, comprising: The film forming apparatus includes: a substrate support portion that supports a substrate; a holder that holds the target, which emits sputter particles, so that the target faces the substrate support; a magnet unit provided on the opposite side of the holder from the substrate support portion and having a magnet; a step of periodically moving the substrate support and periodically moving the magnet unit relative to the target held by the holder, thereby forming a film on the substrate by magnetron sputtering, In this process, The substrate support part and the magnet unit are moved so as to satisfy the following conditions: a total number of movements Nw of the substrate support part during film formation and a total number of movements Nm of the magnet unit during film formation are different natural numbers, the total number of movements Nm is not an integer multiple of the total number of movements Nw, and the total number of movements Nw is not an integer multiple of the total number of movements Nm; When there are a plurality of numbers of movements per unit time of the substrate support part that satisfy the above condition and another condition that the number of movements per unit time of the substrate support part and the magnet unit each fall within a predetermined range, the substrate support part is moved at the largest number of movements per unit time, the film forming apparatus further includes a first shield member and a second shield member that form a processing space; the first shield member has a hole through which the substrate supported by the substrate support portion is exposed to the processing space; the second shield member has an opening; the film forming step includes a step of supplying the sputtered particles from the target held by the holder to the processing space through the opening, A film forming method including a step of rotating the second shield member and switching the portion of the second shield member facing the target held by the holder between the opening and a portion where the opening is not formed.

Images