Plasma processing device and plasma processing method

Abstract

The substrate support of the plasma processing apparatus disclosed in the present invention includes an electrostatic chuck that holds an edge ring. The electrostatic chuck includes a first electrode and a second electrode. During a first plasma treatment of the substrate, the first and second electrodes are each set to one of the same potential and a different potential. During a second plasma treatment of the substrate, the first and second electrodes are each set to another potential. While plasma is being generated, the potentials of the first and second electrodes are switched from one potential to the other.

Description

Technical Field

[0001] Exemplary embodiments of the present invention relate to a plasma processing apparatus and a plasma processing method. Background Art

[0002] Plasma processing of substrates uses a plasma processing apparatus. The plasma processing apparatus includes a chamber and a substrate support. The substrate support is configured to support the substrate within the chamber. An edge ring is mounted on the substrate support. The substrate is positioned within the area surrounded by the edge ring. The edge ring is sometimes referred to as a focus ring.

[0003] The substrate support may include an electrostatic chuck configured to hold an edge ring. This electrostatic chuck is a bipolar type, having two electrodes. A plasma processing apparatus including this type of electrostatic chuck is described in Japanese Patent Application Publication No. 2016-122740. Summary of the Invention

[0004] The present invention provides a technique for suppressing discharge that may occur between an edge ring and a substrate when the potentials of two electrodes set on an electrostatic chuck are switched to hold the edge ring.

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, one or more power supplies, a high-frequency power supply, a bias power supply, and a control unit. The substrate support is configured to support a substrate within the chamber. The substrate support has a lower electrode and an electrostatic chuck. The electrostatic chuck has a first electrode and a second electrode. The electrostatic chuck is configured to hold an edge ring using an electrostatic force generated based on potentials set at the first electrode and the second electrode, respectively. One or more power supplies are electrically connected to the first electrode and the second electrode. The high-frequency power supply is configured to supply high-frequency power to generate plasma within the chamber. The bias power supply is configured to supply bias power to the lower electrode. The control unit is configured to control the one or more power supplies, the high-frequency power supply, and the bias power supply. The control unit controls the high-frequency power supply and the bias power supply to perform a first plasma treatment on a substrate placed on the substrate support. The control unit controls the one or more power supplies to set the potential of the first electrode and the potential of the second electrode to one of the same potential and different potentials during the execution of the first plasma treatment. The control unit controls the high-frequency power supply and the bias power supply to perform a second plasma treatment on a substrate mounted on a substrate support. The control unit sets the effective value of at least one of the high-frequency power and the bias power during the second plasma treatment to a value different from the effective value of the at least one power during the first plasma treatment. The control unit controls one or more power supplies to set the potential of the first electrode and the potential of the second electrode to the same potential or different potential during the second plasma treatment. The control unit controls the one or more power supplies to switch the potential of the first electrode and the second electrode from one potential to the other potential while plasma is generated within the chamber during a switching period. The switching period is the period between the first plasma treatment period and the second plasma treatment period.

[0006] According to an exemplary embodiment, it is possible to suppress discharge that may occur between the edge ring and the substrate when the potentials set at two electrodes of the electrostatic chuck are switched in order to hold the edge ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a diagram schematically showing a plasma processing apparatus according to an exemplary embodiment.

[0008] Figure 2 FIG. 1 is a partially enlarged cross-sectional view of a substrate supporter of a plasma processing apparatus according to an exemplary embodiment.

[0009] Figure 3 FIG. 1 is a plan view showing an exemplary layout of a first electrode and a second electrode on an electrostatic chuck of a plasma processing apparatus according to an exemplary embodiment.

[0010] Figure 4 is a flow chart of a plasma processing method according to an exemplary embodiment.

[0011] Figure 5 This is a timing chart of an example of a plasma processing method according to an exemplary embodiment.

[0012] Figure 6 (a) is a partially enlarged cross-sectional view of an example substrate. Figure 6 (b) is a partially enlarged cross-sectional view of an example of a substrate after step ST1 is performed. Figure 6 (c) is an enlarged partial cross-sectional view of an example of a substrate after step ST2 is performed.

[0013] Figure 7 FIG. 1 is a timing chart of another example of a plasma processing method according to an exemplary embodiment.

[0014] Figure 8 (a) and Figure 8 (b) is a timing chart of another example related to the plasma processing method involved in an exemplary embodiment.

[0015] Figure 9 This is a timing chart of another example of the plasma processing method according to an exemplary embodiment.

[0016] Figure 10 This is a timing chart of another example of the plasma processing method according to an exemplary embodiment.

[0017] Figure 11 This is a timing chart of another example of the plasma processing method according to an exemplary embodiment. DETAILED DESCRIPTION

[0018] Various exemplary embodiments are described below.

[0019] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, one or more power supplies, a high-frequency power supply, a bias power supply, and a control unit. The substrate support is configured to support a substrate within the chamber. The substrate support has a lower electrode and an electrostatic chuck. The electrostatic chuck has a first electrode and a second electrode. The electrostatic chuck is configured to hold an edge ring using an electrostatic force generated based on potentials set at the first electrode and the second electrode, respectively. One or more power supplies are electrically connected to the first electrode and the second electrode. The high-frequency power supply is configured to supply high-frequency power to generate plasma within the chamber. The bias power supply is configured to supply bias power to the lower electrode. The control unit is configured to control the one or more power supplies, the high-frequency power supply, and the bias power supply. The control unit controls the high-frequency power supply and the bias power supply to perform a first plasma treatment on a substrate placed on the substrate support. The control unit controls the one or more power supplies to set the potential of the first electrode and the potential of the second electrode to one of the same potential and different potentials during the execution of the first plasma treatment. The control unit controls the high-frequency power supply and the bias power supply to perform a second plasma treatment on a substrate mounted on a substrate support. The control unit sets the effective value of at least one of the high-frequency power and the bias power during the second plasma treatment to a value different from the effective value of the at least one power during the first plasma treatment. The control unit controls one or more power supplies to set the potential of the first electrode and the potential of the second electrode to the same potential or different potential during the second plasma treatment. The control unit controls the one or more power supplies to switch the potential of the first electrode and the second electrode from one potential to the other potential while plasma is generated within the chamber during a switching period. The switching period is the period between the first plasma treatment period and the second plasma treatment period.

[0020] In the above embodiment, during the first plasma process, the potentials of the first electrode and the second electrode are set to either the same potential or different potentials. That is, during the first plasma process, the electrostatic chuck operates in either a monopolar mode or a bipolar mode. During the second plasma process, the potentials of the first electrode and the second electrode are set to either the same potential or different potentials. That is, during the second plasma process, the electrostatic chuck operates in either a monopolar mode or a bipolar mode. In the above embodiment, the electrostatic chuck mode is switched from one mode to another during the switching period between the first and second plasma processes. During the switching period, plasma is generated in the chamber, thereby suppressing a large potential difference between the substrate and the edge ring. Therefore, according to the above embodiment, discharge that might otherwise occur between the edge ring and the substrate when the potentials of the two electrodes of the electrostatic chuck are switched to maintain the edge ring can be suppressed.

[0021] In an exemplary embodiment, the effective value of at least one power source during the first plasma treatment may be greater than the effective value of at least one power source during the second plasma treatment. In an exemplary embodiment, the control unit may control one or more power sources to set the potential of the first electrode and the potential of the second electrode to the same potential during the first plasma treatment. The control unit may control one or more power sources to set the potential of the first electrode and the potential of the second electrode to different potentials during the second plasma treatment.

[0022] In an exemplary embodiment, the effective value of at least one power source during the first plasma treatment may be less than the effective value of at least one power source during the second plasma treatment. In an exemplary embodiment, the control unit may control one or more power sources to set the potential of the first electrode and the potential of the second electrode to different potentials during the first plasma treatment. The control unit may control one or more power sources to set the potential of the first electrode and the potential of the second electrode to the same potential during the second plasma treatment.

[0023] In an exemplary embodiment, the control unit may control the high-frequency power source and the bias power source to change a level of at least one of the high-frequency power and the bias power during the switching period.

[0024] In an exemplary embodiment, the switching period may be a period immediately following the first plasma processing period. The control unit may control the high-frequency power supply and the bias power supply so that, during the switching period, the level of at least one of the high-frequency power and the bias power gradually decreases relative to the level of the at least one during the first plasma processing period.

[0025] In an exemplary embodiment, the switching period may be a period immediately before the start of the second plasma treatment period. The control unit may control the high-frequency power supply and the bias power supply so that, during the switching period, the level of at least one of the high-frequency power and the bias power gradually increases toward the level of the at least one of the high-frequency power and the bias power during the second plasma treatment period.

[0026] In an exemplary embodiment, the control unit may control the high-frequency power supply and the bias power supply to stop supplying the high-frequency power and the bias power between the switching period and the second plasma processing period.

[0027] In an exemplary embodiment, the level of the high frequency power and / or the level of the bias power may not be set to zero between the period during which the first plasma process is performed and the period during which the second plasma process is performed.

[0028] In an exemplary embodiment, the plasma processing apparatus may further include a gas supply unit configured to supply a first processing gas for the first plasma processing and a second processing gas for the second plasma processing into the chamber. The control unit may control the gas supply unit to maintain a flow rate of the first processing gas during the switching period while the first plasma processing is being performed.

[0029] In an exemplary embodiment, the plasma processing apparatus may further include a gas supply unit configured to supply a first processing gas for the first plasma processing, a second processing gas for the second plasma processing, and an inert gas into the chamber. The control unit may control the gas supply unit to supply only the inert gas into the chamber during the switching period.

[0030] In an exemplary embodiment, the first electrode and the second electrode extend circumferentially around an axis extending in the vertical direction, and the first electrode may extend closer to the axis than the second electrode.

[0031] In an exemplary embodiment, the first electrode and the second electrode may be set to the same positive potential as the common potential. Alternatively, the first electrode may be set to either a positive potential or a negative potential, and the second electrode may be set to either a positive potential or a negative potential as the different potentials.

[0032] In an exemplary embodiment, the plasma processing apparatus may further include a heat transfer gas supply unit configured to supply heat transfer gas to a gap between the electrostatic chuck and the edge ring. The control unit may control the heat transfer gas supply unit to stop supplying the heat transfer gas to the gap during the switching period.

[0033] In another exemplary embodiment, a plasma processing method is provided. The plasma processing method includes performing a first plasma processing on a substrate mounted on a substrate support within a chamber of a plasma processing apparatus. The substrate support includes a lower electrode and an electrostatic chuck. The electrostatic chuck is configured to maintain an edge ring based on potentials set at the first electrode and the second electrode, respectively. During the first plasma processing, the potential of the first electrode and the potential of the second electrode are set to one of the same potential and different potentials. The plasma processing method also includes performing a second plasma processing on the substrate mounted on the substrate support within the chamber. During the second plasma processing, the effective value of at least one of the high-frequency power for generating plasma or the bias power supplied to the lower electrode is set to a value different from the effective value of the at least one power during the first plasma processing. During the second plasma processing, the potential of the first electrode and the potential of the second electrode are set to the other of the same potential and different potentials. The plasma processing method further includes the step of switching the potential of each of the first electrode and the second electrode from the one potential to the other potential while plasma is generated in the chamber during a switching period. The switching period is a period between the first plasma processing period and the second plasma processing period.

[0034] In an exemplary embodiment, the substrate may include a first film and a second film. The first film may be etched by the first plasma treatment, and the second film may be etched by the second plasma treatment.

[0035] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. In addition, in each of the drawings, the same or corresponding parts are marked with the same reference numerals.

[0036] Figure 1 This is a diagram schematically showing a plasma processing apparatus according to an exemplary embodiment. Figure 1The plasma processing apparatus 1 shown is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10. The chamber 10 is provided with an internal space 10s therein. In one embodiment, the chamber 10 may include a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The internal space 10s is provided in the chamber body 12. The chamber body 12 is made of, for example, aluminum. The chamber body 12 is electrically grounded. A plasma-resistant film is formed on the inner wall surface of the chamber body 12, that is, on the wall surface defining the internal space 10s. The film may be a ceramic film such as a film formed by anodizing or a film formed of yttrium oxide.

[0037] A passage 12p is formed in the side wall of the chamber body 12. The substrate W passes through the passage 12p when being transferred between the internal space 10s and the outside of the chamber 10. A gate valve 12g is provided along the side wall of the chamber body 12 to open and close the passage 12p.

[0038] The plasma processing apparatus 1 further includes a substrate support 16. The support 16 is configured to support a substrate W within the chamber 10, that is, within the internal space 10s. The substrate W can have a generally disk-shaped structure. The substrate support 16 is supported by a support member 15. The support member 15 extends upward from the bottom of the chamber body 12. The support member 15 has a generally cylindrical shape and is formed from an insulating material such as quartz.

[0039] The substrate support 16 includes a lower electrode 18 and an electrostatic chuck 20. The substrate support 16 may further include an electrode plate 19. Electrode plate 19 is formed of a conductive material such as aluminum and has a generally disk-shaped configuration. The lower electrode 18 is disposed on electrode plate 19. The lower electrode 18 is formed of a conductive material such as aluminum and has a generally disk-shaped configuration. The lower electrode 18 is electrically connected to the electrode plate 19.

[0040] A flow path 18f is formed in the lower electrode 18. Flow path 18f is a flow path for a heat exchange medium. A liquid refrigerant or a refrigerant that cools the lower electrode 18 by vaporization (e.g., Freon) is used as the heat exchange medium. A heat exchange medium supply device (e.g., a cooling unit) is connected to flow path 18f. The supply device is located outside chamber 10. The heat exchange medium is supplied from the supply device to flow path 18f via pipe 23a. The heat exchange medium supplied to flow path 18f is returned to the supply device via pipe 23b.

[0041] The electrostatic chuck 20 is disposed on the lower electrode 18. An edge ring ER is mounted on the electrostatic chuck 20. The edge ring ER has a ring shape. The edge ring ER is formed, for example, of silicon or silicon carbide. The electrostatic chuck 20 is configured to hold the edge ring ER using electrostatic force. A substrate W is disposed on the substrate support 16 within an area surrounded by the edge ring ER. The substrate W can be placed on and held by the electrostatic chuck 20.

[0042] The plasma processing apparatus 1 may further include a gas supply line 25. The gas supply line 25 supplies a heat transfer gas, such as He gas, from a gas supply mechanism between the upper surface of the electrostatic chuck 20 and the back surface (lower surface) of the substrate W.

[0043] The plasma processing apparatus 1 may further include a cylindrical portion 28 and an insulating portion 29. The cylindrical portion 28 extends upward from the bottom of the chamber body 12. The cylindrical portion 28 extends along the outer circumference of the support body 15. The cylindrical portion 28 is formed of a conductive material and has a substantially cylindrical shape. The cylindrical portion 28 is electrically grounded. The insulating portion 29 is provided on the cylindrical portion 28. The insulating portion 29 is formed of a material having insulating properties. The insulating portion 29 is formed of, for example, ceramics such as quartz. The insulating portion 29 has a substantially cylindrical shape. The insulating portion 29 extends along the outer circumference of the electrode plate 19, the outer circumference of the lower electrode 18, and the outer circumference of the electrostatic chuck 20.

[0044] The plasma processing apparatus 1 further includes an upper electrode 30 . The upper electrode 30 is disposed above the substrate support 16 . The upper electrode 30 and a member 32 together seal the upper opening of the chamber body 12 . The member 32 is insulating. The upper electrode 30 is supported on the upper portion of the chamber body 12 via the member 32 .

[0045] The upper electrode 30 includes a top plate 34 and a support body 36. The lower surface of the top plate 34 defines an internal space 10s. A plurality of gas ejection holes 34a are formed in the top plate 34. The plurality of gas ejection holes 34a penetrate the top plate 34 in the plate thickness direction (vertical direction). The top plate 34 is not limited and can be formed, for example, from silicon. Alternatively, the top plate 34 can have a structure in which a plasma-resistant film is provided on the surface of an aluminum component. The film can be a ceramic film such as a film formed by anodizing or a film formed from yttrium oxide.

[0046] The support body 36 detachably supports the top plate 34. The support body 36 is formed of a conductive material such as aluminum. A gas diffusion chamber 36a is provided within the support body 36. A plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are connected to the plurality of gas outlet holes 34a. A gas port 36c is formed in the support body 36. The gas inlet port 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet port 36c.

[0047] The gas source assembly 40 is connected to the gas supply pipe 38 via a valve assembly 41, a flow controller assembly 42, and a valve assembly 43. The valve assembly 41, the flow controller assembly 42, and the valve assembly 43 constitute a gas supply unit. The gas source assembly 40 includes multiple gas sources. The multiple gas sources include one or more gas sources for the first process gas described below. The multiple gas sources also include one or more gas sources for the second process gas described below. The multiple gas sources may also include a gas source for an inert gas. The inert gas may be, for example, a rare gas.

[0048] The valve group 41 and the valve group 43 each include a plurality of valves (e.g., on-off valves). The flow controller group 42 includes a plurality of flow controllers. The plurality of flow controllers in the flow controller group 42 are respectively mass flow controllers or pressure-controlled flow controllers. The plurality of gas sources in the gas source group 40 are connected to the gas supply pipe 38 via corresponding valves in the valve group 41, corresponding flow controllers in the flow controller group 42, and corresponding valves in the valve group 43. The plasma processing apparatus 1 can supply gas from one or more gas sources selected from the plurality of gas sources in the gas source group 40 to the internal space 10s at individually adjustable flow rates.

[0049] A partition member 48 is provided between the cylindrical portion 28 and the side wall of the chamber body 12. The partition member 48 may be a plate-shaped member. For example, the partition member 48 may be formed by coating a ceramic such as yttrium oxide on an aluminum plate. The partition member 48 has a plurality of through-holes formed therein. Below the partition member 48, an exhaust pipe 52 is connected to the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust pipe 52. The exhaust device 50 includes a pressure controller known as an automatic pressure control valve and a vacuum pump such as a turbomolecular pump, and is capable of reducing the pressure in the internal space 10s.

[0050] The plasma processing apparatus 1 further includes a high-frequency power supply 61. The high-frequency power supply 61 is a power supply for generating high-frequency power HF for plasma generation. The frequency of the high-frequency power HF is not limited and is a frequency in the range of 27 to 100 MHz. The high-frequency power supply 61 is connected to the lower electrode 18 via a matching box 61m and an electrode plate 19 to supply high-frequency power HF to the lower electrode 18. The matching box 61m has a matching circuit. The matching circuit of the matching box 61m has a variable impedance. The impedance of the matching circuit of the matching box 61m is adjusted to reduce reflection of the load from the high-frequency power supply 61. In addition, the high-frequency power supply 61 may not be electrically connected to the lower electrode 18, but may be connected to the upper electrode 30 via the matching box 61m.

[0051] The plasma processing apparatus 1 further includes a bias power supply 62 . The bias power supply 62 generates bias power BP for attracting ions to the substrate W. The bias power supply 62 is connected to the lower electrode 18 via the electrode plate 19 .

[0052] In one embodiment, the bias power supply 62 may be a high-frequency power supply that generates high-frequency power. The frequency of the high-frequency power generated by the bias power supply 62 is lower than the frequency of the high-frequency power HF. The frequency of the high-frequency power generated by the bias power supply 62 is, for example, in the range of 400 kHz to 13.56 MHz. In this embodiment, the bias power supply 62 is connected to the lower electrode 18 via a matching box 62 m and an electrode plate 19. The matching box 62 m includes a matching circuit. The matching circuit of the matching box 62 m has a variable impedance. The impedance of the matching circuit of the matching box 62 m is adjusted to reduce reflection from the load of the bias power supply 62.

[0053] In another embodiment, the bias power supply 62 may be a DC power supply device that intermittently or periodically applies pulses of a negative DC voltage to the lower electrode 18. For example, the bias power supply 62 may apply pulses of a negative DC voltage to the lower electrode 18 within a period defined by a frequency in the range of 1 kHz to 1 MHz.

[0054] In one embodiment, the plasma processing apparatus 1 may further include a DC power supply 64. The DC power supply 64 is connected to the upper electrode 30. The DC power supply 64 is configured to apply a DC voltage, such as a negative DC voltage, to the upper electrode 30. The DC power supply 64 may apply DC voltage pulses to the upper electrode 30 intermittently or periodically.

[0055] When plasma processing is performed in the plasma processing apparatus 1, gas is supplied to the internal space 10s. High-frequency power HF is then supplied to excite the gas in the internal space 10s. As a result, plasma is generated in the internal space 10s. Chemical species such as ions and / or radicals generated from the generated plasma process the substrate W. When bias power BP is supplied to the lower electrode 18, the ions are accelerated toward the substrate W.

[0056] The plasma processing apparatus 1 further includes a control unit MC. This control unit MC is a computer comprising a processor, a storage device, an input device, a display device, and the like, and controls the various components of the plasma processing apparatus 1. Specifically, the control unit MC executes a control program stored in the storage device and controls the various components of the plasma processing apparatus 1 based on recipe data stored in the storage device. Control by the control unit MC enables the plasma processing apparatus 1 to execute the processes specified by the recipe data. Control of the various components of the plasma processing apparatus 1 by the control unit MC enables the plasma processing methods described in the various embodiments described below to be executed in the plasma processing apparatus 1.

[0057] The following, with Figure 1 For reference Figure 2 and Figure 3 . Figure 2FIG. 1 is a partially enlarged cross-sectional view of a substrate supporter of a plasma processing apparatus according to an exemplary embodiment. Figure 3 This is a top view illustrating an exemplary layout of first and second electrodes on an electrostatic chuck of a plasma processing apparatus according to an exemplary embodiment. Electrostatic chuck 20 has a main body formed of a dielectric material such as aluminum nitride or aluminum oxide. Electrostatic chuck 20 includes multiple electrodes within its main body. These electrodes may include a first electrode 20i and a second electrode 20o. These electrodes may also include an electrode 20e.

[0058] In one embodiment, the electrostatic chuck 20 has a first region 20a and a second region 20b. The first region 20a is a substantially circular region when viewed from above. The central axis of the first region 20a is the axis AX extending in the vertical direction. The axis AX can be the central axis of the chamber 10. The first region 20a is configured to support a substrate placed thereon. An electrode 20e is provided within the first region 20a and within the main body. The electrode 20e can be a conductive film. A DC power supply 67 is electrically connected to the electrode 20e. If a DC voltage from the DC power supply 67 is applied to the electrode 20e, an electrostatic force (attraction) is generated between the substrate W and the first region 20a of the electrostatic chuck 20. By the generated electrostatic force, the substrate W is adsorbed to the first region 20a of the electrostatic chuck 20 and is held by the electrostatic chuck 20.

[0059] The second region 20b is an annular region when viewed from above. The second region 20b is outside the first region 20a and extends circumferentially around the axis AX. The second region 20b is configured to hold the edge ring ER mounted thereon. The second region 20b has a first electrode 20i and a second electrode 20o. The first electrode 20i and the second electrode 20o are disposed within the second region 20b and within the main body of the electrostatic chuck 20. In one embodiment, as Figure 3 As shown in FIG, the first electrode 20i and the second electrode 20o extend in the circumferential direction around the axis AX. The first electrode 20i extends at a position closer to the axis AX than the second electrode 20o.

[0060] The first electrode 20i and the second electrode 20o are electrically connected to one or more power sources 66. The one or more power sources 66 may be DC power sources. When the one or more power sources 66 set a potential on each of the first electrode 20i and the second electrode 20o, an electrostatic force (attractive force) is generated between the edge ring ER and the second region 20b. This electrostatic force attracts the edge ring ER to the second region 20b and is held by the electrostatic chuck 20.

[0061] The one or more power supplies 66 can generate a DC voltage to set the potential of the first electrode 20i and the potential of the second electrode 20o to the same potential or different potentials. The setting of the potential of the first electrode 20i and the potential of the second electrode 20o by the one or more power supplies 66 is controlled by the control unit MC.

[0062] In one embodiment, the plasma processing apparatus 1 may further include a heat transfer gas supply unit 68. In this embodiment, the substrate support 16 is provided with a gas supply line 26. The heat transfer gas supply unit 68 is configured to supply an inert gas to the gap between the edge ring ER and the electrostatic chuck 20 via the gas supply line 26. The heat transfer gas supply unit 68 is capable of adjusting the pressure of the inert gas (e.g., He gas) supplied to the gap. The heat transfer gas supply unit 68 may include a flow controller to adjust the pressure of the inert gas.

[0063] refer to Figure 4 . Figure 4 FIG. 1 is a flow chart of a plasma processing method according to an exemplary embodiment. Figure 4 The plasma processing method (hereinafter referred to as "method MT") shown here will be described as an example of a case where it is performed using the plasma processing apparatus 1. In the following description, the control of each component of the plasma processing apparatus 1 by the control unit MC will also be described.

[0064] In the following descriptions, except Figure 4 In addition, reference Figure 5 . Figure 5 This is a timing chart of an example of a plasma processing method according to an exemplary embodiment. Figure 5 , the horizontal axis represents time. Figure 5 In FIG, the vertical axis represents the level of the high frequency power HF, the level of the bias power BP, and the absolute value |VTDC| of the voltage applied to the upper electrode 30 by the DC power supply device 64. Figure 5 In FIG. 1 , the vertical axis also represents the flow rate of the first process gas, the flow rate of the second process gas, and the flow rate of the inert gas supplied into the chamber 10. Figure 5 In FIG, the vertical axis also represents the pressure of the heat transfer gas supplied to the gap between the electrostatic chuck 20 and the edge ring ER. Figure 5 In FIG, the vertical axis also represents the potential of the first electrode 20 i and the potential of the second electrode 20 o.

[0065] When the substrate W is placed on the substrate support 16, Figure 4 The substrate W can be placed on the first area 20 a and held by the electrostatic chuck 20 . Figure 6 (a) is a partial enlarged cross-sectional view of an example of a substrate. Method MT can be applied to Figure 6 The substrate W shown in (a) of FIG. The substrate W includes a first film F1 and a second film F2. The first film F1 is disposed on the second film F2. The first film F1 and the second film F2 can be formed of different materials. The first film F1 and the second film F2 can each be an organic film, a dielectric film, or a metal film. The substrate W further includes a bottom region UR and a mask MK. The second film F2 is disposed on the bottom region UR. The mask MK is disposed on the first film F1. The mask MK provides a pattern that is transferred to the first film F1.

[0066] The method MT starts in step ST1. In step ST1, a first plasma treatment is performed on the substrate W. In step ST1, the substrate W is treated by plasma generated from a first process gas in the chamber 10. The first plasma treatment may be etching of the first film F1 based on chemical substances such as ions and radicals derived from the plasma generated from the first process gas. In step ST1, as shown in FIG. Figure 6 As shown in (b), the first film F1 is etched, and the pattern of the mask MK is transferred to the first film F1.

[0067] During step ST1, that is, during period P1, the controller MC controls the gas supply unit to supply the first process gas into the chamber 10. The first process gas includes a gas for etching the first film F1. The first process gas may also include an inert gas. During period P1, the controller MC controls the exhaust device 50 to set the gas pressure in the chamber 10 to a specified pressure.

[0068] During period P1, the control unit MC controls the high-frequency power source 61 to supply high-frequency power HF for plasma generation. During period P1, the high-frequency power HF may be supplied continuously. Alternatively, pulses of the high-frequency power HF may be supplied intermittently or periodically. During period P1, the control unit MC controls the bias power source 62 to supply bias power BP to the lower electrode 18. During period P1, the bias power BP may be supplied continuously. Alternatively, pulses of the bias power BP may be supplied intermittently or periodically.

[0069] During period P1, the control unit MC may control the DC power supply device 64 to apply a negative DC voltage to the upper electrode 30. During period P1, the negative DC voltage from the DC power supply device 64 may be continuously applied to the upper electrode 30. Alternatively, during period P1, pulses of the negative DC voltage from the DC power supply device 64 may be intermittently or periodically applied to the upper electrode 30.

[0070] During the period P1, the control unit MC controls the one or more power supplies 66 so as to set the potential of the first electrode 20i and the potential of the second electrode 20o to one of the same potential and different potentials. Figure 5 In the example shown, during period P1, the first electrode 20i and the second electrode 20o are set to the same positive potential. During period P1, the controller MC controls the heat transfer gas supply unit 68 to supply heat transfer gas to the gap between the electrostatic chuck 20 and the edge ring ER.

[0071] The method MT further includes a step ST2. Step ST2 is performed after step ST1. In step ST2, a second plasma treatment is performed on the substrate W. In step ST2, the substrate W is treated by plasma generated from the second process gas in the chamber 10. The second plasma treatment may be etching of the second film F2 based on chemical substances such as ions and radicals derived from the plasma generated from the second process gas. In step ST2, as shown in FIG. Figure 6 As shown in (c), the second film F2 is etched, and the pattern of the mask MK is transferred to the second film F2.

[0072] During step ST2, i.e., during period P2, the controller MC controls the gas supply unit to supply the second process gas into the chamber 10. The second process gas includes a gas for etching the second film F2. The second process gas may also include an inert gas. During period P2, the controller MC controls the exhaust device 50 to set the gas pressure in the chamber 10 to a specified pressure.

[0073] During period P2, the control unit MC controls the high-frequency power source 61 to supply high-frequency power HF for plasma generation. During period P2, the high-frequency power HF may be supplied continuously. Alternatively, pulses of the high-frequency power HF may be supplied intermittently or periodically. During period P2, the control unit MC controls the bias power source 62 to supply bias power BP to the lower electrode 18. During period P2, the bias power BP may be supplied continuously. Alternatively, pulses of the bias power BP may be supplied intermittently or periodically.

[0074] The control unit MC sets the effective value of at least one of the high-frequency power HF and the bias power BP in the period P2 to a value different from the effective value of the at least one of the powers in the period P1. Figure 5 In the example shown, the effective value of the high-frequency power HF in the period P1 is greater than the effective value of the high-frequency power HF in the period P2. Figure 5In the example shown, the effective value of the bias power BP during period P1 is greater than the effective value of the bias power BP during period P2. Furthermore, when pulses of high-frequency power HF are intermittently or periodically supplied during each of periods P1 and P2, the effective value is represented by the product of the level of the pulses of the high-frequency power HF and the duty cycle. The duty cycle is the ratio of the ON time to the sum of the ON time and the OFF time. High-frequency power HF is supplied during the ON time. High-frequency power HF is not supplied during the OFF time. Furthermore, when pulses of bias power BP are intermittently or periodically supplied during each of periods P1 and P2, the effective value is represented by the product of the level of the pulses of the bias power BP (the absolute value of the power level or voltage level) and the duty cycle. The duty cycle is the ratio of the ON time to the sum of the ON time and the OFF time. Bias power BP is supplied during the ON time. No bias power BP is supplied during the OFF time.

[0075] During period P2, the control unit MC may control the DC power supply device 64 to apply a negative DC voltage to the upper electrode 30. During period P2, the negative DC voltage from the DC power supply device 64 may be continuously applied to the upper electrode 30. Alternatively, during period P2, pulses of the negative DC voltage from the DC power supply device 64 may be intermittently or periodically applied to the upper electrode 30.

[0076] During the period P2, the control unit MC controls the one or more power supplies 66 so as to set the potential of the first electrode 20i and the potential of the second electrode 20o to the same potential or to different potentials. Figure 5 In the example shown, during the period P2, the first electrode 20i and the second electrode 20o are set to different potentials. Figure 5 In the example shown, during period P2, the potential of the first electrode 20i is set to a positive potential, and the potential of the second electrode 20o is set to a negative potential. During period P2, the controller MC controls the heat transfer gas supply unit 68 to supply heat transfer gas to the gap between the electrostatic chuck 20 and the edge ring ER.

[0077] The method MT further includes a step STA. The step STA is performed between the step ST1 and the step ST2. That is, during the switching period P1 between the period P2 SW Execute process STA. During the switching period P SW In a state where plasma is generated in the chamber 10 , the potential of each of the first electrode 20 i and the second electrode 20 o is switched from the one potential to the other potential.

[0078] In one embodiment, if Figure 5 As shown, during the switching period P SWThe control unit MC can control the gas supply unit to switch the period P1 to the next period. SW The flow rate of the first processing gas during the maintenance period P1 is maintained. Figure 7 As shown, the control unit MC can control the gas supply unit to SW Only inert gas is supplied into the chamber 10. SW The control unit MC controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a specified pressure.

[0079] During the switching period, P SW The control unit MC controls the high-frequency power supply 61 and the bias power supply 62 to continuously supply the high-frequency power HF and the bias power BP, so that a state in which plasma is generated from the gas is formed in the chamber 10 .

[0080] During the switching period, P SW The control unit MC controls one or more power supplies 66 to switch the potential of each of the first electrode 20i and the second electrode 20o from the above-mentioned one potential to the above-mentioned other potential. Figure 5 In the example shown, the potentials of the first electrode 20i and the second electrode 20o are switched from the same potential to different potentials. SW The set potentials of the first electrode 20 i and the second electrode 20 o are also maintained during the period P2 .

[0081] In one embodiment, the control unit MC can control the high frequency power supply 61 and the bias power supply 62 so that during the switching period P SW The level of at least one of the high-frequency power HF and the bias power BP is changed.

[0082] In one embodiment, if Figure 5 As shown, during the switching period P SW The control unit MC controls the high frequency power supply 61 and the bias power supply 62 so that the high frequency power supply 61 and the bias power supply 62 are switched during the switching period P1. SW , so that the level of the at least one power gradually decreases relative to the level of the at least one power in period P1. Figure 5 In the example shown, during the switching period P SW , the level of the high frequency power HF gradually decreases relative to the level of the high frequency power HF in the period P1. Figure 5 In the example shown, during the switching period P SW , the level of the bias power BP gradually decreases relative to the level of the bias power BP in the period P1. SWThe density of the plasma in the chamber 10 during the period P1 is lower than that during the period P2. SW The substrate W is processed.

[0083] In one embodiment, the control unit MC controls the heat transfer gas supply unit 68 so that during the switching period P SW , stop supplying heat transfer gas to the gap between the electrostatic chuck 20 and the edge ring ER. According to this embodiment, during the switching period P SW The edge ring ER is prevented from coming off the electrostatic chuck 20 .

[0084] In one embodiment, the method MT may further include a step STB. Step STB is performed between the step STA and the step ST2. That is, during the switching period P SW Period P between period P2 ST The control unit MC can control the high frequency power supply 61 and the bias power supply 62 to ST , stop the supply of high frequency power HF and bias power BP. Figure 5 As shown, the gas in the chamber 10 can be switched to the second processing gas in a state where plasma is not generated in the chamber 10 .

[0085] In method MT, during the execution of the first plasma treatment (period P1), the potential of the first electrode 20i and the potential of the second electrode 20o are set to either the same potential or different potentials. That is, during period P1, the electrostatic chuck 20 functions in either the monopolar mode or the bipolar mode. During the execution of the second plasma treatment (period P2), the potential of the first electrode 20i and the potential of the second electrode 20o are set to either the same potential or different potentials. That is, during period P2, the electrostatic chuck 20 functions in either the monopolar mode or the bipolar mode. During the switching period P1 between period P2 and period P2, the electrostatic chuck 20 functions in either the monopolar mode or the bipolar mode. SW , the mode of the electrostatic chuck 20 is switched from one mode to another. During the switching period P SW Plasma is generated within the chamber 10, thereby suppressing a large potential difference between the substrate W and the edge ring ER. This suppresses discharge, which could potentially occur between the edge ring ER and the substrate W when the potentials of the two electrodes (20i and 20o) set on the electrostatic chuck 20 are switched to maintain the edge ring ER. As a result, for example, particles attached to the edge ring ER can be prevented from melting due to discharge below the back surface of the substrate W, thereby preventing the melted particles from contaminating the substrate W.

[0086] Below, reference Figure 8(a) Figure 8 (b) Figure 9 、 Figure 10 and Figure 11 These figures are timing charts of yet another example of the plasma processing method according to one exemplary embodiment.

[0087] like Figure 8 As shown in (a), the control unit MC can set the potentials of the first electrode 20i and the second electrode 20o to different potentials during the period P1 and to the same potential during the period P2. SW , the potentials of the first electrode 20i and the second electrode 20o are switched from different potentials to the same potential and maintained during the period P2. Figure 8 In the example shown in (a), during the period P1, the potential of the first electrode 20i is set to a positive potential, and the potential of the second electrode 20o is set to a negative potential. Figure 8 In the example shown in (a) of FIG. 2 , in the period P2 , the potential of the first electrode 20 i and the potential of the second electrode 20 o are set to the same positive potential.

[0088] like Figure 8 As shown in (b), the control unit MC can set the potentials of the first electrode 20i and the second electrode 20o to be the same potential during the period P1, and to different potentials during the period P2. Figure 8 In the example shown in (b), during the period P1, the potential of the first electrode 20i and the potential of the second electrode 20o are set to the same positive potential. Figure 8 In the example shown in (b), during the period P2, the potential of the first electrode 20i is set to a negative potential, and the potential of the second electrode 20o is set to a positive potential. Figure 8 In the example shown in (b), during the switching period P SW , the potentials of the first electrode 20i and the second electrode 20o are switched from the same potential to different potentials, and are maintained during the period P2.

[0089] like Figure 9 As shown, between period P1 and period P2, that is, during the switching period P SW With period P ST , the level of the high frequency power HF and / or the level of the bias power BP may not be set to zero. Figure 9In the example shown, the level of the high-frequency power HF and the level of the bias power BP do not need to be set to zero between periods P1 and P2. Between periods P1 and P2, the level of the high-frequency power HF may gradually change from its level during period P1 to its level during period P2. Furthermore, between periods P1 and P2, the level of the bias power BP may gradually change from its level during period P1 to its level during period P2.

[0090] like Figure 10 As shown in FIG. 1 , the effective value of at least one of the high-frequency power HF and the bias power BP during the period P1 can be set to a smaller value than the effective value of the at least one of the powers during the period P2. Figure 10 In the example shown, the effective value of the high-frequency power HF during the period P1 is smaller than the effective value of the high-frequency power HF during the period P2. Figure 10 In the example shown, the effective value of the bias power BP during the period P1 is smaller than the effective value of the bias power BP during the period P2. Figure 10 As shown, the control unit MC can set the potentials of the first electrode 20 i and the second electrode 20 o to different potentials during the period P1 and to the same potential during the period P2 .

[0091] like Figure 11 As shown, during the switching period P SW It can be the period immediately before the start of period P2. At this time, the control unit MC can control the high frequency power supply 61 and the bias power supply 62 so that during the switching period P SW The level of at least one of the high frequency power HF or the bias power BP is gradually increased. For example, during the switching period P SW The level of the one type of power in the period P2 may gradually increase toward the level of the at least one type of power in the period P3. Figure 11 In the example shown, during the switching period P SW , the level of the high frequency power HF gradually increases toward its level in period P2. Figure 11 In the example shown, during the switching period P SW , the level of the bias power BP gradually increases toward its level in the period P2.

[0092] Although various exemplary embodiments have been described above, the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and changes may be made. Furthermore, elements of different embodiments may be combined to form another embodiment.

[0093] For example, in another embodiment, the plasma processing apparatus having the substrate support 16 may be a plasma processing apparatus different from the plasma processing apparatus 1. Examples of such a plasma processing apparatus include a capacitively coupled plasma processing apparatus, an inductively coupled plasma processing apparatus, or a plasma processing apparatus that generates plasma using surface waves such as microwaves, which are different from the plasma processing apparatus 1.

[0094] Alternatively, the first region 20a and the second region 20b may be provided as separate electrostatic chucks. That is, in another embodiment, the electrostatic chuck holding the edge ring ER may be a different electrostatic chuck from the electrostatic chuck holding the substrate W.

[0095] As will be appreciated from the foregoing description, various embodiments of the present invention are described in this specification for illustrative purposes and are susceptible to various modifications without departing from the scope and spirit of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are indicated by the scope of the appended claims.

Claims

1. A plasma processing apparatus comprising: chamber; a substrate support configured to support the substrate in the chamber and comprising a lower electrode and an electrostatic chuck, wherein the electrostatic chuck comprises a first electrode and a second electrode and holds the edge ring by electrostatic force generated according to potentials set at the first electrode and the second electrode; one or more power sources electrically connected to the first electrode and the second electrode, a high-frequency power supply configured to supply high-frequency power to generate plasma in the chamber; a bias power supply configured to supply bias power to the lower electrode; and a control unit configured to control the one or more power supplies, the high-frequency power supply, and the bias power supply; The control unit performs the following control: controlling the high-frequency power supply and the bias power supply to perform a first plasma treatment on the substrate placed on the substrate support, and controlling the one or more power supplies to set the potential of the first electrode and the potential of the second electrode to one of the same potential and different potentials during the execution of the first plasma treatment, The high-frequency power supply and the bias power supply are controlled to perform a second plasma process on the substrate placed on the substrate support, and the one or more power supplies are controlled to set an effective value of at least one of the high-frequency power or the bias power during the second plasma process to a value different from the effective value of the at least one power during the first plasma process, and to set the potential of the first electrode and the potential of the second electrode during the second plasma process to the other of the same potential and the different potentials. The one or more power supplies are controlled to switch the potential of each of the first electrode and the second electrode from the one potential to the other potential while plasma is generated in the chamber during switching between the execution period of the first plasma treatment and the execution period of the second plasma treatment.

2. The plasma processing apparatus according to claim 1, wherein The effective value of the at least one type of power during the execution period of the first plasma process is greater than the effective value of the at least one type of power during the execution period of the second plasma process.

3. The plasma processing apparatus according to claim 2, wherein: The control unit performs the following control: controlling the one or more power supplies so as to set the potential of the first electrode and the potential of the second electrode to be the same potential during the execution period of the first plasma treatment, The one or more power supplies are controlled so that the potential of the first electrode and the potential of the second electrode are set to different potentials during the execution period of the second plasma process.

4. The plasma processing apparatus according to claim 1, wherein The effective value of the at least one type of power during the execution period of the first plasma process is smaller than the effective value of the at least one type of power during the execution period of the second plasma process.

5. The plasma processing apparatus according to claim 4, wherein: The control unit performs the following control: controlling the one or more power supplies so as to set the potential of the first electrode and the potential of the second electrode to different potentials during the execution period of the first plasma treatment, The one or more power supplies are controlled so that the potential of the first electrode and the potential of the second electrode are set to be the same potential during the execution period of the second plasma process.

6. The plasma processing apparatus according to any one of claims 1 to 5, wherein: The control unit controls the high-frequency power supply and the bias power supply to change a level of at least one of the high-frequency power and the bias power during the switching period.

7. The plasma processing apparatus according to any one of claims 1 to 5, wherein: The switching period is a period immediately following the execution period of the first plasma process. The control unit controls the high-frequency power supply and the bias power supply so that, during the switching period, the level of the at least one power gradually decreases relative to the level of the at least one power during the execution period of the first plasma process.

8. The plasma processing apparatus according to any one of claims 1 to 5, wherein: The switching period is a period immediately before the execution period of the second plasma process begins. The control unit controls the high-frequency power supply and the bias power supply so that, during the switching period, the level of the at least one power gradually increases toward the level of the at least one power during the execution period of the second plasma process.

9. The plasma processing apparatus according to any one of claims 1 to 5, wherein: The control unit controls the high-frequency power supply and the bias power supply to stop supplying the high-frequency power and the bias power between the switching period and the execution period of the second plasma process.

10. The plasma processing apparatus according to any one of claims 1 to 5, wherein: Between the execution period of the first plasma process and the execution period of the second plasma process, the level of the high-frequency power and / or the level of the bias power is not set to zero.

11. The plasma processing apparatus according to claim 7, further comprising: a gas supply unit configured to supply a first processing gas for the first plasma processing and a second processing gas for the second plasma processing into the chamber; The control unit controls the gas supply unit so as to maintain the flow rate of the first process gas during the execution period of the first plasma process during the switching period.

12. The plasma processing apparatus according to any one of claims 1 to 5, further comprising: a gas supply unit configured to supply a first processing gas for the first plasma processing, a second processing gas for the second plasma processing, and an inert gas into the chamber; The control unit controls the gas supply unit to supply only the inert gas into the chamber during the switching period.

13. The plasma processing apparatus according to any one of claims 1 to 5, wherein: The first electrode and the second electrode extend in a circumferential direction around an axis extending in a vertical direction, and the first electrode extends at a position closer to the axis than the second electrode.

14. The plasma processing apparatus according to any one of claims 1 to 5, wherein: The first electrode and the second electrode are respectively set to the same positive potential as the same potential. One of a positive potential and a negative potential is set at the first electrode, and the other of a positive potential and a negative potential is set at the second electrode as the different potentials.

15. The plasma processing apparatus according to any one of claims 1 to 5, further comprising: a heat transfer gas supply unit configured to supply heat transfer gas to a gap between the electrostatic chuck and the edge ring; The control unit controls the heat transfer gas supply unit to stop supplying the heat transfer gas to the gap during the switching period.

16. A plasma treatment method comprising: performing a first plasma treatment on a substrate placed on a substrate support in a chamber of a plasma processing apparatus, wherein during the first plasma treatment, the potentials of a first electrode and a second electrode of an electrostatic chuck of the substrate support configured to hold an edge ring are set to one of the same potential and different potentials; performing a second plasma treatment on the substrate placed on the substrate support in the chamber, wherein during the second plasma treatment, an effective value of at least one of high-frequency power for generating plasma and bias power supplied to a lower electrode of the substrate support is set to a value different from the effective value of the at least one power during the first plasma treatment, and the potentials of the first electrode and the second electrode are set to the other of the same potential and the different potentials, respectively; and The step of switching the potential of each of the first electrode and the second electrode from the one potential to the other potential while plasma is generated in the chamber during a switching period between the execution period of the first plasma process and the execution period of the second plasma process.

17. The plasma processing method according to claim 16, wherein: The substrate has a first film and a second film, etching the first film by the first plasma treatment, The second film is etched by the second plasma treatment.

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