Plasma processing equipment

Abstract

The present invention provides a plasma processing apparatus, comprising a control unit that executes the following steps a to e: step a of placing a substrate on a substrate support; step b of forming a first plasma from a first gas in a chamber using a first RF signal and a second RF signal, in which the second RF signal is supplied to a lower electrode at a first electric power greater than 0 in step b; step c of exposing the substrate to the first plasma; step d of forming a second plasma from a second gas in the chamber using the first RF signal, the second RF signal, and a magnetic field, in which the second RF signal is supplied to the lower electrode at a second electric power greater than the first electric power; and step e of exposing the substrate to the second plasma.

Description

Technical Field

[0001] Embodiments of the present invention relate to a plasma processing apparatus. Background Art

[0002] In the manufacture of electronic devices, a plasma processing apparatus is used to perform a plasma processing method to process a workpiece. Generally speaking, the plasma processing apparatus includes a chamber body, a gas supply unit, a mounting table, a first high-frequency power supply, and a second high-frequency power supply. The gas supply unit supplies gas to the internal space of the chamber body. The mounting table is arranged in the internal space of the chamber body and supports the workpiece placed thereon. The workpiece is placed on the mounting table in such a manner that its center is located on the central axis of the chamber body. The mounting table includes a lower electrode. The first high-frequency power supply generates a first high-frequency for generating plasma. The second high-frequency power supply generates a second high-frequency. The frequency of the second high-frequency is lower than the frequency of the first high-frequency. The second high-frequency is supplied to the lower electrode. In the plasma processing method using the plasma processing apparatus, the gas is excited in the internal space by the first high-frequency to generate plasma. In addition, by supplying the second high-frequency to the lower electrode, ions in the plasma are accelerated toward the workpiece, and the accelerated ions are irradiated onto the workpiece.

[0003] As one of the plasma processing methods, there is a plasma processing method in which two plasma treatments are sequentially applied to a workpiece. Such a plasma processing method is described in Patent Document 1. The plasma processing method described in Patent Document 1 is performed to selectively etch a first region formed of silicon oxide relative to a second region formed of silicon nitride. In this plasma processing method, a treatment using a plasma of a fluorocarbon gas and a treatment using a plasma of a rare gas are performed. In the treatment using the plasma of a fluorocarbon gas, a film containing a deposit of fluorocarbons is formed on the workpiece. In the treatment using the plasma of a fluorocarbon gas, the electric power of the second high frequency is set to a relatively low electric power (for example, 0 watts). In the plasma treatment using the rare gas, ions of the rare gas are irradiated onto the workpiece. In the plasma treatment using the rare gas, the second region is protected by the film of the deposit, and the first region is etched by free radicals of the fluorocarbons in the film of the deposit. In the plasma treatment using the rare gas, the electric power of the second high frequency is set to a relatively high electric power. The plasma processing method is used to etch the first region disposed within the recess provided by the second region, thereby adaptively forming an opening.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-173240 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] As electronic devices become increasingly miniaturized, the width of the aforementioned recesses becomes narrower. If a thicker deposit forms on the first region within the narrow recess, etching of the first region using the rare gas plasma process will not proceed. Therefore, the thickness of the deposit film formed on the workpiece needs to be reduced. When the thickness of the deposit film decreases, the energy of the rare gas ions irradiating the workpiece needs to be reduced to suppress etching of the second region. To reduce the ion energy, a second, higher frequency can be used. When the second, higher frequency is used, the following electric field intensity distribution is formed: higher at the center of the workpiece and lower at the edges. In other words, within the internal space, a nonuniform electric field intensity distribution is formed, with the electric field intensity decreasing with increasing distance from the central axis in the radial direction. As a result, a nonuniform plasma density distribution is formed in the radial direction relative to the central axis. This plasma density distribution leads to radial nonuniformity in the plasma process. Therefore, there is a need to make the plasma density distribution uniform in rare gas plasma processes. In addition, in any plasma processing method including the following processing, it is also required to make the distribution of plasma density in performing the second plasma processing uniform, and the above-mentioned processing is a first plasma processing in which the electric power of the second high frequency (high frequency for bias) is set to a lower electric power and a second plasma processing in which the electric power of the second high frequency is set to a lower electric power.

[0009] Technical solutions to technical problems

[0010] In one embodiment, a plasma processing method performed using a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber body, a mounting table, a gas supply unit, a first high-frequency power supply, a second high-frequency power supply, and an electromagnet. The mounting table disposed in the internal space includes a lower electrode, which provides a mounting area for a workpiece. The center of the mounting area is located on the central axis of the chamber body. The gas supply unit supplies a first gas and a second gas to the internal space of the chamber body. The first high-frequency power supply generates a first high frequency for generating plasma. The second high-frequency power supply generates a second high frequency and is electrically connected to the lower electrode. The frequency of the second high frequency is lower than that of the first high frequency. The electromagnet forms a magnetic field in the internal space of the chamber body.

[0011] A plasma processing method according to one embodiment is performed with a workpiece contained in the interior space of a chamber body. The plasma processing method includes: (i) performing a first plasma processing step on the workpiece, wherein the workpiece is processed using plasma of a first gas supplied to the interior space; and (ii) performing a second plasma processing step on the workpiece, wherein the workpiece is processed using plasma of a second gas supplied to the interior space. The electric power of the second high frequency set in the second plasma processing step is greater than the electric power of the second high frequency set in the first plasma processing step. In the second plasma processing step, an electromagnet is used to form a magnetic field distribution having a larger horizontal component on the edge of the workpiece than on the center of the workpiece.

[0012] In one embodiment of a plasma processing method, during the second plasma processing, the electric field intensity increases at the center of the workpiece and decreases at the edge of the workpiece. That is, during the second plasma processing, an uneven distribution of electric field intensity is formed in the radial direction relative to the central axis. In addition, during the second plasma processing, the above-mentioned magnetic field distribution is formed in the internal space. The residence time of electrons increases in the area where the magnetic field with a large horizontal component is formed. As a result, the density of plasma increases in the area where the magnetic field with a large horizontal component is formed. Therefore, the distribution of plasma density during the second plasma processing is uniformized. However, since the distribution of plasma density is uniformized using the magnetic field distribution formed by the electromagnet, the distribution of plasma density can be uniformized at a high speed at the moment of switching from the first plasma processing to the plasma processing for performing the second plasma processing.

[0013] In one embodiment, the first plasma treatment and the second plasma treatment are alternately repeated. When the first plasma treatment and the second plasma treatment are alternately repeated, the plasma density distribution can be uniformed at a high speed when the plasma treatment switches from the first plasma treatment to the second plasma treatment.

[0014] In one embodiment, a workpiece includes a first region formed of silicon oxide and a second region formed of silicon nitride. The first gas includes a fluorocarbon gas. During the first plasma treatment step, a film containing a deposit of the fluorocarbon is formed on the workpiece. The second gas includes a rare gas. During the second plasma treatment step, the workpiece having the deposit film formed thereon is irradiated with ions of the rare gas, thereby etching the first region. In this embodiment, since the second region is protected by the deposit film while the first region is etched, the first region is selectively etched relative to the second region.

[0015] In one embodiment, the first region is disposed in a recess provided by the second region. In this embodiment, the first region disposed in the recess of the second region is etched to adaptively form an opening.

[0016] In one embodiment, the frequency of the second high frequency is greater than 13.56 MHz. In one embodiment, the frequency of the second high frequency is greater than 40 MHz. In one embodiment, the frequency of the second high frequency is greater than 60 MHz.

[0017] Effects of the Invention

[0018] As described above, in the plasma processing method including the first plasma processing and the second plasma processing, the plasma density distribution can be made uniform in the second plasma processing in which the high-frequency bias power is set to a relatively high power. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a flowchart illustrating a plasma processing method according to one embodiment.

[0020] Figure 2 It is summarized in Figure 1 FIG. 1 is a diagram of a plasma processing apparatus according to one embodiment that can be used in performing a plasma processing method.

[0021] Figure 3 This is a graph showing calculation results of the distribution of electric field intensity in the internal space of the chamber body.

[0022] Figure 4 Yes Figure 2 FIG. 1 is a plan view of the internal structure of a ground conductor of a plasma processing apparatus.

[0023] Figure 5 It means using Figure 2 The calculation results of the magnetic field distribution that can be generated by the plasma processing device are shown.

[0024] Figure 6 Yes Figure 2 FIG. 1 is a graph showing measurement results of ion beam distribution in the internal space of a plasma processing apparatus.

[0025] Figure 7 It can be applied Figure 1 A partially enlarged cross-sectional view of a workpiece according to an example of an embodiment of the method shown.

[0026] Figure 8 It is from Figure 7 A partially enlarged cross-sectional view of a workpiece in the state shown.

[0027] exist Figure 9 middle, Figure 9 (a) is Figure 1 A partially enlarged cross-sectional view of the workpiece in a state after step ST1 is performed in one embodiment of the method shown, Figure 9 (b) is Figure 1 FIG. 1 is an enlarged partial cross-sectional view of a workpiece in a state after step ST2 is performed in one embodiment of the method shown.

[0028] Figure 10 It is applied Figure 1 An enlarged partial cross-sectional view of a workpiece after one embodiment of the method is shown.

[0029] Description of Reference Numerals

[0030] 10…plasma processing device; 12…chamber body; 12s…inner space; 14…support table; 14r…support area; 18…lower electrode; 20…electrostatic chuck; 36…upper electrode; 41…gas supply unit; 42…cooling device; 43…first high-frequency power supply; 44…second high-frequency power supply; 48…power supply conductor; 50…ground conductor; 51…first portion; 52…second portion; 53…third portion; 60…electromagnet; 64…coil; AX…center axis; ES…external space; IS1…first space; IS2…second space; IS3…third space; W…workpiece; R1…first region; R2…second region; DP…film. DETAILED DESCRIPTION

[0031] Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. In addition, in each of the drawings, the same reference numerals are given to the same or corresponding parts.

[0032] Figure 1 1 is a flowchart illustrating a plasma processing method according to one embodiment. Figure 1The plasma processing method shown (hereinafter referred to as “method MT”) is performed with a workpiece accommodated in the internal space of a chamber body of a plasma processing apparatus.

[0033] Figure 2 It is summarized in Figure 1 FIG. 1 is a diagram of a plasma processing apparatus according to an embodiment of the present invention that can be used in performing the plasma processing method. Figure 2 , a plasma processing apparatus 10 according to one embodiment is shown in a state where it is partially cut along a plane extending in a vertical direction. Figure 2 The plasma processing apparatus 10 shown includes a chamber body 12. The chamber body 12 has a cylindrical shape and includes a sidewall 12a and a bottom 12b. The chamber body 12 provides an inner space 12s. Figure 2 The central axis AX shown is the central axis of the chamber body 12 and the internal space 12s. The chamber body 12 is formed of a metal such as aluminum. A plasma-resistant film is formed on the inner wall surface of the chamber body 12. This film can be a ceramic film such as an aluminum oxide film or a yttrium oxide film. The chamber body 12 is grounded.

[0034] A passage 12p is formed in the sidewall 12a. When a workpiece W is transported between the interior space 12s and the exterior of the chamber body 12, the workpiece W passes through the passage 12p. The workpiece W can be disc-shaped, such as a wafer. The passage 12p can be opened and closed by a gate valve 12g, which is provided along the sidewall 12a.

[0035] A mounting table 14 is provided in the internal space 12s. The mounting table 14 is supported by a support 15. The support 15 has a cylindrical shape and extends upward from the bottom 12b of the chamber body 12. The support 15 has insulating properties and is formed of, for example, ceramic.

[0036] The mounting table 14 is configured to support a workpiece W. The mounting table 14 and the chamber body 12 share a central axis AX. The mounting table 14 provides a mounting area 14r. The center of the mounting area 14r is located on the central axis AX. The workpiece W is mounted on the mounting area 14r with its center located on the central axis AX.

[0037] The mounting table 14 includes an electrode plate 16, a lower electrode 18, and an electrostatic chuck 20. The electrode plate 16 has a substantially disk-like shape. The electrode plate 16 is electrically conductive. The electrode plate 16 is formed of a metal such as aluminum. The lower electrode 18 has a disk-like shape. The lower electrode 18 is electrically conductive. The lower electrode 18 is formed of a metal such as aluminum. The lower electrode 18 is mounted on the electrode plate 16 and is electrically connected to the electrode plate 16.

[0038] A flow path 18p is formed in the lower electrode 18. The flow path 18p extends in the lower electrode 18, for example, in a spiral shape. A heat exchange medium (e.g., a refrigerant) is supplied to the flow path 18p from a heat exchange medium circulation device 22 (e.g., a chiller unit). The circulation device 22 is located outside the chamber body 12. The heat exchange medium supplied to the flow path 18p returns to the circulation device 22. The heat exchange between the heat exchange medium and the lower electrode 18 controls the temperature of the workpiece W placed on the mounting table 14.

[0039] The electrostatic chuck 20 is provided on the lower electrode 18. The electrostatic chuck 20 has a substantially disc shape. The electrostatic chuck 20 has a film-shaped electrode in a ceramic body. The electrode of the electrostatic chuck 20 is connected to a DC power supply 24 via a switch. The electrostatic chuck 20 provides the above-mentioned loading area 14r. When a DC voltage from the DC power supply 24 is applied to the electrode of the electrostatic chuck 20 while the workpiece W is loaded on the electrostatic chuck 20 (on the loading area 14r), an electrostatic attraction is generated between the workpiece W and the electrostatic chuck 20. The generated electrostatic attraction is used to attract the workpiece W to the electrostatic chuck 20 and to be held by the electrostatic chuck 20. A heat transfer gas supply line for supplying a heat transfer gas (e.g., He gas) between the electrostatic chuck 20 and the lower surface of the workpiece W may also be provided in the plasma processing apparatus 10.

[0040] One or more heaters (e.g., one or more resistance heating elements) may be provided inside the electrostatic chuck 20. When electrical power is supplied to the one or more heaters from a heating controller, the one or more heaters generate heat to adjust the temperature of the electrostatic chuck 20 or the temperature of the workpiece W.

[0041] Within the interior space 12s of the chamber body 12, a focus ring FR is disposed to surround the electrostatic chuck 20 and the edge of the workpiece W. The focus ring FR is an annular plate formed of a silicon-containing material such as silicon or quartz. The focus ring FR is used to achieve uniformity in plasma processing.

[0042] A cylindrical conductor 26 is provided around the support member 15. The conductor 26 is grounded. A cylindrical insulator 28 is provided above the conductor 26 so as to surround the mounting table 14. The insulator 28 is formed of a ceramic such as quartz. An exhaust path is formed between the mounting table 14 and the side wall 12a of the chamber body 12. A buffer plate 30 is provided in the exhaust path. The buffer plate 30 is an annular plate. A plurality of holes are formed in the buffer plate 30 that penetrate the buffer plate 30 in the thickness direction of the plate. The buffer plate 30 is formed by forming a plasma-resistant film such as yttrium oxide on the surface of a base material formed of a metal such as aluminum.

[0043] Below the buffer plate 30, an exhaust pipe 32 is connected to the bottom 12b of the chamber body 12. The exhaust pipe 32 is able to communicate with the exhaust path. It is connected to an exhaust device 34. The exhaust device 34 includes an automatic pressure control valve and a pressure-reducing pump such as a turbomolecular pump. The operation of the exhaust device 34 sets the pressure of the internal space 12s to a specified value.

[0044] An upper electrode 36 is provided above the mounting table 14. A portion of the internal space 12s is defined between the upper electrode 36 and the mounting table 14. The upper electrode 36 is provided to close the upper opening of the chamber body 12. A component 37 is provided between the upper electrode 36 and the upper end of the chamber body 12. The component 37 is formed of an insulating material. The component 37 is formed of ceramic, such as quartz. In one embodiment, the component 37 and a portion of a ground conductor (described later) may be provided between the upper electrode 36 and the upper end of the chamber body 12.

[0045] In one embodiment, the upper electrode 36 constitutes a showerhead. In one embodiment, the upper electrode 36 includes a top plate 38 and a support member 40. The top plate 38 is formed, for example, of silicon. Alternatively, the top plate 38 may be formed by coating a ceramic layer, such as yttrium oxide, on the surface of an aluminum substrate. A plurality of gas outlets 38h are formed in the top plate 38, penetrating the top plate 38 in the thickness direction.

[0046] The support member 40 is mounted on the top plate 38. The support member 40 removably supports the top plate 38. The support member 40 is formed from a conductive material such as aluminum. A gas diffusion chamber 40d is formed within the support member 40. The support member 40 is formed with a plurality of holes 40h extending downward from the gas diffusion chamber 40d. The plurality of holes 40h are connected to the plurality of gas outlets 38h.

[0047] The gas diffusion chamber 40d is connected to the gas supply unit 41. The gas supply unit 41 supplies gas to the internal space 12s. In one embodiment, the gas supply unit 41 is capable of outputting a first gas and a second gas. The first gas and the second gas will be described later. In addition, the gas supply unit 41 has one or more flow controllers and one or more valves to independently adjust the flow rate of one or more gases to be output. The gas output from the gas supply unit 41 is discharged into the internal space 12s from a plurality of gas outlets 38h via the gas diffusion chamber 40d and a plurality of holes 40h.

[0048] A flow path 40p is formed in the support member 40. The flow path 40p is connected to a cooling device 42. A refrigerant such as cooling water circulates between the flow path 40p and the cooling device 42. The temperature of the upper electrode 36 can be adjusted by heat exchange between the refrigerant supplied from the cooling device 42 to the flow path 40p and the upper electrode 36.

[0049] The plasma processing apparatus 10 further includes a first high-frequency power supply 43 and a second high-frequency power supply 44. The first high-frequency power supply 43 and the second high-frequency power supply 44 are arranged outside the chamber body 12. The first high-frequency power supply 43 mainly generates a first high frequency for generating plasma. The first high frequency is not limited and can be a frequency of 100 MHz, for example. The first high-frequency power supply 43 is electrically connected to the upper electrode 36 via a matcher 45 and a power supply conductor 48. The matcher 45 has a matching circuit for matching the output impedance of the first high-frequency power supply 43 with the impedance of the load side (upper electrode 36 side). The lower end of the power supply conductor 48 is connected to the upper electrode 36. The power supply conductor 48 extends upward from the upper electrode 36. The power supply conductor 48 is a cylindrical or rod-shaped conductor, and its central axis is roughly consistent with the central axis AX.

[0050] The second high-frequency power supply 44 mainly generates a second high frequency for introducing ions into the workpiece W, that is, a high frequency for biasing. The frequency of the second high frequency is lower than the frequency of the first high frequency. In one embodiment, the frequency of the second high frequency is higher than 13.56 MHz. In one embodiment, the frequency of the second high frequency may be above 40 MHz. In one embodiment, the frequency of the second high frequency may be above 60 MHz. The second high-frequency power supply 44 is electrically connected to the lower electrode 18 via a matcher 46. The matcher 46 has a matching circuit for matching the output impedance of the second high-frequency power supply 44 with the impedance of the load side (lower electrode 18 side).

[0051] The plasma processing apparatus 10 further includes a grounding conductor 50. The grounding conductor 50 is electrically conductive and is formed of a metal such as aluminum. The grounding conductor 50 is grounded. The grounding conductor 50 extends above the chamber body 12 to cover the upper electrode 36. The power supply conductor 48 extends upward through the space enclosed by the grounding conductor 50 to the outside of the grounding conductor 50 and is connected to the first high-frequency power supply 43 via the matching unit 45 outside the grounding conductor 50.

[0052] In the internal space 12s of the chamber body 12 of the plasma processing apparatus 10, an electric field intensity distribution can be formed in which the electric field intensity is higher above the center of the workpiece W and lower above the edge of the workpiece W. In other words, in the internal space 12s, a non-uniform electric field intensity distribution can be formed in which the electric field intensity decreases as the distance from the central axis AX in the radiation direction (i.e., radial direction) increases. Figure 3 This is a graph showing the calculation results of the distribution of electric field intensity in the internal space of the chamber body. Figure 3 In the figure, the horizontal axis represents the distance from the central axis AX to the radiation direction, and the vertical axis represents the normalized electric field intensity. Figure 3, the distribution of normalized electric field intensity when multiple second high frequency frequencies f2 are used respectively is shown. Figure 3 As shown in FIG. 1 , the higher the second high frequency f2, the more pronounced the nonuniformity of the electric field intensity in the radiation direction. Furthermore, if the second high frequency f2 is set to a higher frequency, the energy of the ions irradiated to the workpiece W becomes smaller.

[0053] Under this nonuniform electric field strength distribution, the plasma density is higher near the central axis and lower away from the central axis. In other words, a nonuniform plasma density distribution is formed in the radial direction relative to the central axis. To achieve a uniform plasma density distribution even in processes that create this nonuniform electric field strength distribution, such as those utilizing a second high frequency having a higher frequency, the plasma processing apparatus 10 further includes an electromagnet 60.

[0054] like Figure 2 As shown, the electromagnet 60 is disposed above the upper electrode 36. The electromagnet 60 forms a magnetic field distribution in the internal space 12s of the chamber body 12, wherein a horizontal component at a position away from the central axis AX is larger than the horizontal component on the central axis AX. Specifically, the electromagnet 60 forms a magnetic field distribution in the internal space 12s having a horizontal component that increases in magnitude as the distance from the central axis AX in the radial direction increases. Electrons reside longer in areas where a magnetic field with a larger horizontal component is formed. As a result, the plasma density increases in areas where a magnetic field with a larger horizontal component is formed. Therefore, the plasma processing apparatus 10 can achieve a uniform plasma density distribution in the radial direction relative to the central axis AX. Consequently, the plasma processing apparatus 10 can improve the in-plane uniformity of the processing of the workpiece W.

[0055] In one embodiment, the electromagnet 60 has a yoke 62 and a coil 64. The yoke 62 is formed of a magnetic material. The yoke 62 has a base 62a and a plurality of cylindrical portions 62b. The base 62a has a roughly disc shape and extends in a direction perpendicular to the central axis AX. The plurality of cylindrical portions 62b each have a cylindrical shape and extend downward from the base 62a. The plurality of cylindrical portions 62b are coaxially arranged relative to the central axis AX. The coil 64 is wound around the central axis AX. The coil 64 is arranged between two radially adjacent cylindrical portions 62b. In addition, the electromagnet 60 may have more than one coil 64. When the number of coils 64 in the electromagnet 60 is multiple, the plurality of coils 64 are coaxially arranged relative to the central axis AX.

[0056] The coil 64 of the electromagnet 60 is connected to a current source 66 via wiring 68. When current from the current source 66 is applied to the coil 64, a magnetic field is generated by the electromagnet 60. Because the electron confinement effect (the effect of suppressing electron diffusion) and the electron annihilation suppression effect (the effect of suppressing the arrival of electrons heading toward the electrode) in the region where the vector angle of the magnetic field generated by the electromagnet 60 is 45° can coexist effectively, the plasma density in this region increases. Therefore, when the radius of the workpiece W is 150 mm, the electromagnet 60 can be configured so that the distance between the region where the vector angle of the magnetic field is 45° and the central axis AX is greater than 135 mm and less than 185 mm. Therefore, in one embodiment, the average of the inner and outer diameters of one coil 64 of the electromagnet 60 is greater than the distance between the central axis AX and the edge of the workpiece W. When the radius of the workpiece W is 150 mm, the average of the inner and outer diameters of one coil 64 of the electromagnet 60 is greater than 150 mm and less than 250 mm. The angle of the magnetic field vector is 0° when the magnetic field has only a downward component, and 90° when the magnetic field has only a radiating component (horizontal component). Therefore, when the angle of the magnetic field vector is 45°, the magnetic field has both a horizontal component and a vertical component.

[0057] When the electromagnet 60 is placed in the space surrounded by the grounded conductor covering the upper electrode, the first high frequency energy flows into the electromagnet 60 and / or the wiring connecting the electromagnet 60 to the power supply (current source). As a result, the electric field strength in the internal space 12s of the chamber body 12 changes locally. Therefore, the electromagnet 60 is placed outside the grounded conductor. However, if the electromagnet 60 is placed in a space above the upper end of the grounded conductor, the vertical distance from the electromagnet 60 to the internal space 12s becomes longer, and a magnetic field of sufficient strength cannot be effectively formed in the internal space 12s without applying a large current to the coil 64. Furthermore, if the electromagnet 60 is placed to the side of the grounded conductor (outside the grounded conductor in the radial direction from the central axis), a location within the internal space 12s where a magnetic field with a large horizontal component or a magnetic field with a vector angle of 45° cannot be formed. In order to effectively form an appropriate magnetic field distribution for obtaining a uniform plasma density distribution in the internal space 12s, an external space ES in which the electromagnet 60 is disposed is provided within the ground conductor 50. The external space ES is located closer to the internal space 12s than the upper end of the ground conductor 50, is spaced upward relative to the upper electrode 36, and is shielded from the upper electrode 36 by the ground conductor 50.

[0058] The ground conductor 50 includes a first portion 51, a second portion 52, and a third portion 53. The first portion 51 has a cylindrical shape. The central axis of the first portion 51 is substantially consistent with the central axis AX. The first portion 51 extends upward from the chamber body 12. Figure 2 In the illustrated example, the first portion 51 extends upward from the upper end of the side wall 12a of the chamber body 12. The lower end portion of the first portion 51 is disposed between the component 37 and the upper end of the side wall 12a.

[0059] The second portion 52 moves upward away from the upper electrode 36 and extends from the first portion 51 toward the central axis AX. The second portion 52 is in the shape of a plate extending in a direction intersecting or orthogonal to the central axis AX. The first portion 51 and the second portion 52 provide a first space IS1 on the upper electrode 36. The first space IS1 is a portion of the space on the inner side of the grounding conductor 50 (i.e., on the upper electrode 36 side). By utilizing this first space IS1, a distance can be ensured between the upper electrode 36 and the grounding conductor 50 in the vertical direction. Therefore, capacitive coupling between the grounding conductor 50 and the upper electrode 36 can be suppressed. The vertical distance between the upper surface of the upper electrode 36 and the lower surface of the second portion 52 of the grounding conductor 50 is set to, for example, a distance of 60 mm or more.

[0060] The third portion 53 has a cylindrical shape. The central axis of the third portion 53 is substantially aligned with the central axis AX. The third portion 53 extends closer to the central axis than the first portion 51. The third portion 53 extends upward from the second portion 52. The third portion 53 provides a second space IS2. The second space IS2 is the space inside the second portion 52 and is a portion of the space inside the ground conductor 50 (i.e., on the upper electrode 36 side). The second space IS2 is connected to the first space IS1. In addition, the power supply conductor 48 extends upward through the first space IS1 and the second space IS2.

[0061] The external space ES is provided by the ground conductor 50 outside the third portion 53, on the second portion 52, and above the internal space 12s. The external space ES extends circumferentially about the central axis AX, outside the third portion 53 and on the second portion 52. An electromagnet 60 is disposed in the external space ES. Furthermore, the vertical distance between the lower end of the electromagnet 60 disposed in the external space ES and the upper surface of the upper electrode 36 can be greater than 60 mm, and the vertical distance between the lower end of the electromagnet 60 and the workpiece W placed on the mounting table 14 can be less than 230 mm.

[0062] The distance between the electromagnet 60, located in the external space ES, and the internal space 12s is relatively short. Furthermore, as described above, the electromagnet 60 has a low horizontal component near the central axis AX, while forming a magnetic field distribution in the internal space 12s with a large horizontal component away from the central axis. Therefore, by using the electromagnet 60, located outside the ground conductor 50, a magnetic field distribution appropriately distributed for achieving a uniform plasma density can be effectively formed in the internal space 12s.

[0063] As described above, the coil 64 of the electromagnet 60 is connected to the current source 66. The electromagnet 60 and the current source 66 are arranged outside the ground conductor 50. Therefore, a filter for preventing high frequency from flowing into the current source 66 does not need to be provided between the coil 64 and the current source 66.

[0064] In one embodiment, the ground conductor 50 further includes a fourth portion 54, a fifth portion 55, and a sixth portion 56. The fourth portion 54 extends radially from the third portion 53 above the second portion 52. The fourth portion 54 is plate-shaped, extending in a direction intersecting or perpendicular to the central axis AX. The fifth portion 55 is cylindrical. The central axis of the fifth portion 55 is substantially aligned with the central axis AX. The fifth portion 55 is further from the central axis than the third portion 53 and extends upward from the fourth portion 54. The sixth portion 56 extends from the fifth portion 55 above the fourth portion 54 toward the central axis AX. The sixth portion 56 is plate-shaped, extending in a direction intersecting or perpendicular to the central axis AX. In one embodiment, the ground conductor 50 further includes a cover portion 57 extending from the sixth portion to near the power supply conductor 48.

[0065] The fourth portion 54, the fifth portion 55, and the sixth portion 56 provide a third space IS3. The third space IS3 is a space surrounded by the fourth portion 54, the fifth portion 55, and the sixth portion 56, and is a portion of the space inside the ground conductor 50. The third space IS3 is connected to the second space IS2. The power supply conductor 48 also extends upward through the third space IS3. Figure 2 In the example shown, the first to sixth portions are composed of three components, but the number of components constituting the ground conductor 50 may be any number.

[0066] Below, refer to Figure 2 and Figure 4 . Figure 4 Yes Figure 2 A plan view of the internal structure of a ground conductor of a plasma processing apparatus is shown. Figure 4 , the fifth portion 55 of the ground conductor 50 is shown cut off in a horizontal plane. Figure 2 and Figure 4As shown, the plasma processing apparatus 10 further includes a tube 71 (first tube). The tube 71 extends upward from the upper electrode 36 through the first space IS1 and the second space IS2, and extends laterally and externally relative to the ground conductor 50 through the third space IS3. The tube 71 is connected to the cooling device 42 externally relative to the ground conductor 50. Refrigerant from the cooling device 42 is supplied to the flow path 40p via the tube 71. Within the third space IS3, the tube 71 is substantially shielded from the upper electrode 36 by the fourth portion 54 of the ground conductor 50.

[0067] The plasma processing apparatus 10 further includes a tube 72. The tube 72 extends upward through the first space IS1 and the second space IS2, and extends laterally and externally relative to the ground conductor 50 through the third space IS3. The tube 72 is connected to the cooling device 42 externally relative to the ground conductor 50. The refrigerant returns to the cooling device 42 from the flow path 40p via the tube 72. Within the third space IS3, the tube 72 is substantially shielded from the upper electrode 36 by the fourth portion 54 of the ground conductor 50.

[0068] In one embodiment, the plasma processing apparatus 10 further includes a tube 73 (second tube). The tube 73 extends upward from the upper electrode 36 through the first space IS1 and the second space IS2, and extends to the side and outside relative to the ground conductor 50 through the third space IS3. The tube 73 is connected to the gas supply unit 41 on the outside relative to the ground conductor 50. The gas output from the gas supply unit 41 is supplied to the upper electrode 36, i.e., the showerhead, via the tube 73. In the third space IS3, the tube 73 is substantially shielded from the upper electrode 36 by the fourth portion 54 of the ground conductor 50. In addition, the gas supply unit 41 and the upper electrode 36 (i.e., the showerhead) can be connected to each other through a plurality of tubes.

[0069] In one embodiment, the plasma processing apparatus 10 further includes a DC power supply 74 and a wiring 75. The DC power supply 74 generates a negative DC voltage applied to the upper electrode 36. The wiring 75 connects the DC power supply 74 and the upper electrode 36 to each other. The wiring 75 may include a coil 75c. The coil 75c is disposed in the third space IS3. The wiring 75 extends upward from the upper electrode 36 through the first space IS1 and the second space IS2, and extends laterally and externally relative to the ground conductor 50 through the third space IS3. The wiring 75 is electrically insulated from the fifth portion 55 and the ground conductor 50. The wiring 75 is connected to the DC power supply 74 on the outside of the ground conductor 50. Within the third space IS3, the wiring 75 is substantially shielded from the upper electrode 36 by the fourth portion 54 of the ground conductor 50.

[0070] In one embodiment, the plasma processing apparatus 10 further includes a control unit 80. The control unit 80 controls the various components of the plasma processing apparatus 10. The control unit 80 may be a computer device. The control unit 80 may include a storage device such as a processor and a memory, an input device such as a keyboard, a mouse, a touch panel, a display device, an input and output interface for control signals, and the like. A control program and scheme data are stored in the storage device. The processor of the control unit 80 executes the control program and sends control signals to control the various components of the plasma processing apparatus 10 according to the scheme data. In order to execute method MT, the control unit 80 is capable of controlling the various components of the plasma processing apparatus 10.

[0071] Below, refer to Figure 5 . Figure 5 It means using Figure 2 The graph of the calculated results of the magnetic field distribution that can be formed by the plasma processing device shown in FIG. Figure 5 In the figure, the horizontal axis represents the distance from the central axis AX, and the vertical axis represents the magnetic flux density. Figure 5 , the distribution of the magnetic flux density representing the distribution of the magnetic field BA, the distribution of the magnetic flux density representing the distribution of the horizontal component BH of the magnetic field BA, and the distribution of the magnetic flux density representing the distribution of the vertical component BV of the magnetic field BA are shown. Figure 5 The distribution of the magnetic field and its two components shown is the distribution within a plane 174 mm below the lower end of the electromagnet 60, that is, the distribution within the upper surface of the mounting table 14. Figure 5 The conditions for calculating the distribution of the magnetic field and its two components are as follows.

[0072] Calculation conditions

[0073] Inner diameter (radius) of coil 64: 132 mm

[0074] Coil 64 outer diameter (radius): 173 mm

[0075] Number of turns of coil 64: 215 turns

[0076] Current supplied to coil 64: 4 [A]

[0077] The distance between the lower end of the electromagnet 60 and the workpiece W placed on the mounting table 14 is 174 mm.

[0078] according to Figure 5 The calculation results of the magnetic field distribution shown show that the use of the electromagnet 60 can form a magnetic field distribution having a larger horizontal component on the central axis AX at a portion away from the central axis AX.

[0079] Below, refer to Figure 6 . Figure 6 Yes Figure 2 The graph of the measurement results of the distribution of ion flux in the internal space of the plasma processing device shown in FIG. Figure 6 In the experiment showing the measurement results, a disc-shaped sample was placed on a mounting table 14, plasma was generated in the internal space 12s, and a magnetic field was formed in the internal space 12s using an electromagnet 60. The rate of increase (dT / dt) of the sample's temperature per unit time was then determined at multiple measurement points along the sample's diameter. The rate of increase (dT / dt) is a parameter that reflects the amount of ion flow. In the experiment, the current supplied to the coil 64 with the electromagnet 60 was set to 0 [A], 1 [A], 4 [A], and 6.5 [A], and the distribution of the ion flow was measured. Other experimental conditions are shown below.

[0080] Experimental conditions

[0081] Pressure in the internal space for 12 seconds: 20 mTorr (2.67 Pa)

[0082] Gas supplied to the inner space for 12s: 1000 sccm of Ar gas

[0083] First high frequency: 60MHz, 100W

[0084] Second high frequency: 40MHz, 100W

[0085] exist Figure 6 In the diagram, the horizontal axis represents the position of each of the multiple measurement points, indicating the distance from the central axis AX. A measurement point specified by a positive distance is located on one side of the central axis AX on the diameter mentioned above, and a measurement point specified by a negative distance is located on the other side of the central axis AX on the diameter mentioned above. Figure 6 In the figure, the vertical axis represents the rate of increase (dT / dt). Figure 6 As shown, when the current supplied to coil 64 of electromagnet 60 is 0 [A], the rate of increase (dT / dt), that is, the ion current, decreases as the distance from the central axis AX increases. Specifically, when the current supplied to coil 64 is 0 [A], an uneven plasma density distribution is formed. As the current supplied to coil 64 increases, the difference in ion current at multiple measurement points decreases. This confirms that the formation of a magnetic field in internal space 12s by electromagnet 60 can create a uniform plasma density distribution.

[0086] Refer again Figure 1The method MT will be described by taking the case where the plasma processing apparatus 10 is used as an example. The method MT is executed when the workpiece W is accommodated in the internal space 12s of the chamber body 12. Figure 1 As shown, method MT includes step ST1 and step ST2.

[0087] In step ST1, a first plasma treatment is performed on the workpiece W. In step ST1, the workpiece W is treated using the plasma of the first gas supplied to the internal space 12s. In step ST1, a second high frequency may or may not be supplied to the lower electrode 18. When the second high frequency is supplied to the lower electrode 18 in step ST1, the power of the second high frequency set in step ST1 is lower than the power of the second high frequency supplied to the lower electrode 18 in step ST2.

[0088] In step ST2, a second plasma treatment is performed on the workpiece W. In step ST2, the workpiece W is treated using the plasma of the second gas supplied to the internal space 12s. In step ST2, a second high frequency is supplied to the lower electrode 18. In step ST2, the power of the second high frequency is set to a higher power than that of the second high frequency in step ST1. In one embodiment, the frequency of the second high frequency is greater than 13.56 MHz. The frequency of the second high frequency can be greater than 40 MHz or greater than 60 MHz.

[0089] In step ST2 , a magnetic field distribution having a larger horizontal component on the edge side of the workpiece W than on the center of the workpiece W is formed in the internal space 12 s by the electromagnet 60 .

[0090] Steps ST1 and ST2 can be repeated alternately. While steps ST1 and ST2 are being repeated alternately, a determination is made in step ST3 as to whether a stop condition is satisfied. For example, the stop condition is satisfied when the sequence including steps ST1 and ST2 has been executed a predetermined number of times. If the stop condition is not satisfied in step ST3, step ST1 is executed again, followed by step ST2. On the other hand, if the stop condition is satisfied in step ST3, execution of method MT ends.

[0091] In step ST2 of method MT, the power of the second high frequency is set to a higher power than the power of the second high frequency set in step ST1. Therefore, during the second plasma treatment in step ST2, the electric field intensity is higher at the center of the workpiece W and lower at the edges of the workpiece W. That is, during the second plasma treatment, a non-uniform electric field intensity distribution is formed in the radial direction relative to the central axis AX. During the second plasma treatment, the aforementioned magnetic field distribution is formed within the internal space 12s. Electrons spend longer dwelling time in areas with a larger horizontal magnetic field component. As a result, the plasma density increases in areas with a larger horizontal magnetic field component. Therefore, the plasma density distribution during the second plasma treatment is uniform. However, since the plasma density distribution is uniformed using the magnetic field distribution formed by the electromagnet 60, the plasma density distribution can be uniformed at high speed when switching from the first plasma treatment to the second plasma treatment. When step ST1 and step ST2 are alternately repeated, it is very advantageous to use the electromagnet 60 that can uniformize the plasma density distribution at high speed.

[0092] In one embodiment, the first gas includes a fluorocarbon gas, such as C4F8 gas. The second gas includes a rare gas such as He gas, Ne gas, Ar gas, Kr gas, or Xe gas. Method MT of this embodiment can selectively etch the first region formed of silicon oxide relative to the second region formed of silicon nitride.

[0093] Figure 7 It can be applied Figure 1 A partially enlarged cross-sectional view of an example of a workpiece according to one embodiment of the method shown. Figure 7 The workpiece W shown includes a base region UR, a plurality of raised regions PR, a first region R1, a second region R2, and a mask MK. The workpiece W may be a product obtained in the manufacture of a fin-type field-effect transistor, for example.

[0094] The base region UR can be made of, for example, polysilicon. In one example, the base region UR is a fin-shaped region having a roughly rectangular parallelepiped shape. A plurality of raised regions PR are provided on the base region UR and are arranged roughly parallel to each other. These raised regions PR can be, for example, gate regions. The second region R2 is formed of silicon nitride. The second region R2 is provided to cover the raised region PR and the base region UR. The second region R2 provides a recess between two adjacent raised regions PR. The first region R1 is formed of silicon oxide. The first region R1 is provided in the above-mentioned recess provided by the second region R2. In addition, the first region R1 is provided to cover the second region R2. A mask MK is provided on the first region R1. The mask MK is drawn so as to provide an opening above the recess provided by the second region R2. The width of the opening of the mask MK is greater than the width of the recess provided by the second region R2. The mask MK is a mask formed of an organic film. The mask MK can be manufactured using photolithography technology.

[0095] Below, to apply to Figure 7 The method MT of one embodiment will be described using the case of the workpiece W shown as an example. However, the method MT of one embodiment can be applied to any workpiece having a first region formed of silicon oxide and a second region formed of silicon nitride. Figure 1 and Figure 7 In addition, refer to Figure 8 、 Figure 9 (a) Figure 9 (b) and Figure 10 . Figure 8 It is from Figure 7 A partially enlarged cross-sectional view of a workpiece in the state shown. Figure 9 (a) is Figure 1 A partially enlarged cross-sectional view of a workpiece in a state after step ST1 is performed according to one embodiment of the method shown. Figure 9 (b) is Figure 1 FIG. 1 is a partially enlarged cross-sectional view of a workpiece in a state after step ST2 is performed according to one embodiment of the method shown. Figure 10 It is applied Figure 1 An enlarged partial cross-sectional view of a workpiece after one embodiment of the method is shown.

[0096] In the method MT of one embodiment, the first region R1 may be etched only through steps ST1 and ST2. Alternatively, the etching may be performed before the initial step ST1 until the second region R2 is exposed (see Figure 8 ) or until the second region R2 is about to be exposed, the first region R1 is etched by other plasma etching processes. For example, until the second region R2 is exposed (refer to Figure 8) or until the second region R2 is about to be exposed, the first region R1 can be etched using active species such as ions and / or free radicals from the plasma of the fluorocarbon gas.

[0097] In step ST1 of method MT according to one embodiment, the workpiece W is processed using a plasma of the aforementioned first gas containing a fluorocarbon gas. The first gas may contain a rare gas such as oxygen or Ar gas in addition to the fluorocarbon gas. In step ST1, a film DP containing a deposit of fluorocarbons is formed on the workpiece W. In step ST1, the film DP is formed such that the film thickness of the film DP on the second region R2 is greater than the film thickness of the film DP on the first region R1.

[0098] Specifically, in step ST1, the first gas is supplied to the internal space 12s, and the pressure in the internal space 12s is reduced to a predetermined pressure by the exhaust device 34. The supply of the first high frequency excites the first gas in the internal space 12s. As a result, plasma of the first gas is generated in the internal space 12s. In step ST1, the power of the second high frequency is set to be lower than that of the second high frequency in step ST2. In step ST1, the second high frequency does not necessarily need to be supplied to the lower electrode 18.

[0099] In step ST1, the temperature of the workpiece W is set to a temperature between 20°C and 250°C. The temperature of the workpiece W is adjusted by the heat exchange medium supplied to the flow path 18p and the one or more heaters provided in the electrostatic chuck 20. When the temperature of the workpiece W is set to the above temperature, Figure 9 As shown in (a), a film DP containing a deposit of fluorocarbon is formed on the workpiece W. Figure 9 As shown in (a), the film thickness of the film DP is greater in the second region R2 and smaller in the first region R1. Furthermore, temperatures exceeding 250°C are the glass transition temperature of the mask MK, and at these temperatures, the difference in film thickness between the film DP formed in the first region R1 and the film DP formed in the second region R2 decreases. Furthermore, at temperatures below 20°C, the difference in film thickness between the film DP formed in the first region R1 and the film DP formed in the second region R2 decreases.

[0100] In step ST2, the workpiece W processed in step ST1 is processed using the plasma of the above-mentioned second gas containing a rare gas. The second gas may be a gas containing only a rare gas. Alternatively, the second gas may contain oxygen in addition to the rare gas. In step ST2, the second gas is supplied to the internal space 12s, and the pressure of the internal space 12s is reduced to a specified pressure using the exhaust device 34. By supplying the second high frequency, the second gas is excited in the internal space 12s. As a result, a plasma of the second gas is generated in the internal space 12s. In step ST2, the second high frequency is supplied to the lower electrode 18. In step ST2, the electric power of the second high frequency is set to be higher than the electric power of the second high frequency in step ST1.

[0101] In step ST2, the workpiece W is irradiated with ions of a rare gas. When the rare gas ions are irradiated to the film DP, the first region R1 is etched by radicals of the fluorocarbon contained in the film DP. On the other hand, although the film DP on the second region R2 is reduced, the second region R2 is protected in such a manner as to suppress the etching of the second region R2. When step ST2 is executed, Figure 9 The workpiece W shown in (a) becomes Figure 9 Then, by alternately repeating step ST1 and step ST2, as shown in (b). Figure 10 As shown, the first region R1 in the recess provided by the second region R2 is removed to form the opening HL. That is, the opening HL is formed adaptively.

[0102] However, when the width of the recess provided by the second region R2 is narrow, executing step ST1 forms a thicker deposit on the first region R1 within the narrow recess. If a thicker deposit film forms on the first region R1, etching of the first region R1 will not occur in step ST2. Therefore, when the width of the recess provided by the second region R2 is narrow, the thickness of the deposit film DP formed on the workpiece W needs to be reduced. When the thickness of the deposit film DP is small, the energy of the rare gas ions irradiating the workpiece W needs to be reduced to suppress etching of the second region R2. This ion energy can be reduced by using a second high frequency. For example, a second high frequency with a frequency greater than 13.56 MHz, a frequency greater than 40 MHz, or a frequency greater than 60 MHz can be used. When using a second high frequency with a higher frequency, the unevenness in the distribution of the electric field strength formed in step ST2 becomes more pronounced. By forming the magnetic field using the electromagnet 60 in step ST2, this unevenness is eliminated or suppressed.

[0103] While various embodiments have been described above, the present invention is not limited to the aforementioned embodiments and various variations are possible. Method MT can be performed using a plasma processing apparatus other than plasma processing apparatus 10, namely, any plasma processing apparatus capable of supplying a second high frequency (bias high frequency) to the lower electrode and forming a magnetic field distribution within the interior space of the chamber body that is identical to the magnetic field distribution formed by electromagnet 60. Examples of such plasma processing apparatuses include capacitively coupled plasma processing apparatuses that supply a first high frequency to the lower electrode, inductively coupled plasma processing apparatuses, and plasma processing apparatuses that utilize surface waves such as microwaves to excite gas.

[0104] Additionally, the electromagnet of the plasma processing apparatus used in method MT may have more than one coil.

Claims

1. A plasma processing device, characterized in that include: a chamber having at least one inlet for a first gas and a second gas; a substrate support disposed in the chamber, the substrate support having a surface for supporting a substrate, the surface having a first area and a second area surrounding the first area; a lower electrode disposed within the substrate support; a first RF power supply supplying a first RF signal having a first frequency; a second RF power source electrically connected to the lower electrode, the second RF power source supplying a second RF signal having a second frequency lower than the first frequency; an electromagnet that forms a magnetic field in the chamber, the magnetic field having a first component at the first region and a second component greater than the first component at the second region; and The control unit performs the following steps a to e, Step a) of placing a substrate on the substrate support; Step b) of forming a first plasma from the first gas in the chamber using the first RF signal and the second RF signal, wherein in step b, the second RF signal is supplied to the lower electrode at a first electric power of 0 or more; step c) exposing the substrate to the first plasma; step d) forming a second plasma from the second gas in the chamber using the first RF signal, the second RF signal, and the magnetic field, wherein in step d) the second RF signal is supplied to the lower electrode at a second electric power greater than the first electric power; and step e) exposing the substrate to the second plasma, The control unit executes step f, which repeatedly executes steps b to e.

2. The plasma processing apparatus according to claim 1, wherein: The substrate comprises: a first material containing silicon oxide and a second material containing silicon nitride, The first gas comprises a fluorocarbon gas, In step c, a film containing a fluorocarbon is formed on the substrate, the second gas comprises a rare gas, In step e, the first material on the substrate is etched.

3. A plasma processing device, characterized in that include: a chamber having at least one inlet for a first gas and a second gas; a substrate support disposed in the chamber, the substrate support having a surface for supporting a substrate, the surface having a first area and a second area surrounding the first area; a lower electrode disposed within the substrate support; a first RF power supply supplying a first RF signal having a first frequency; a second RF power source electrically connected to the lower electrode, the second RF power source supplying a second RF signal having a second frequency lower than the first frequency; an electromagnet that forms a magnetic field in the chamber, the magnetic field having a first component at the first region and a second component greater than the first component at the second region; and The control unit performs the following steps a to e, Step a) of placing a substrate on the substrate support; Step b) of forming a first plasma from the first gas in the chamber using the first RF signal and the second RF signal, wherein in step b, the second RF signal is supplied to the lower electrode at a first electric power of 0 or more; step c) exposing the substrate to the first plasma; step d) forming a second plasma from the second gas in the chamber using the first RF signal, the second RF signal, and the magnetic field, wherein in step d) the second RF signal is supplied to the lower electrode at a second electric power greater than the first electric power; and step e) exposing the substrate to the second plasma, The substrate comprises: a first material containing silicon oxide and a second material containing silicon nitride, The first gas comprises a fluorocarbon gas, In step c, a film containing a fluorocarbon is formed on the substrate, the second gas comprises a rare gas, In step e, the first material on the substrate is etched.

4. The plasma processing apparatus according to claim 2 or 3, wherein: The second material has a recessed portion, and the first material is disposed in the recessed portion.

5. The plasma processing apparatus according to claim 1 or 3, wherein: The second frequency is greater than 13.56 MHz.

6. The plasma processing apparatus according to claim 5, wherein: The second frequency is greater than 40 MHz.

7. The plasma processing apparatus according to claim 5, wherein: The second frequency is greater than 60 MHz.

8. The plasma processing apparatus according to claim 1 or 3, wherein: further comprising an upper electrode disposed above the substrate support and electrically connected to the first RF power source, The electromagnet is disposed above the upper electrode.

9. The plasma processing apparatus according to claim 8, wherein: The first distance between the electromagnet and the upper electrode is greater than 60 mm, A second distance between the electromagnet and the substrate placed on the substrate support is 230 mm or less.

10. The plasma processing apparatus according to claim 8, wherein: The electromagnet includes one or more coils arranged coaxially with the central axis of the chamber.

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