Plasma processing apparatus and power supply system

Abstract

To provide a technique for controlling energy of ions supplied from plasma to a substrate.SOLUTION: In the plasma processing apparatus according to an exemplary embodiment, a pulsed negative direct-current voltage is periodically applied to a lower electrode. A frequency defining the period in which the pulsed negative direct-current voltage is applied to the lower electrode is lower than the frequency of high-frequency power supplied to generate plasma. The high-frequency power is supplied during a first partial period within the period. The power level of the high-frequency power in a second partial period within the period is set to a power level reduced from the power level of the high-frequency power in the first partial period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Exemplary embodiments of the present disclosure relate to a plasma processing apparatus and a plasma processing method. [Background technology]

[0002] A plasma processing apparatus is used for plasma processing of a substrate. Patent Document 1 listed below describes one type of plasma processing apparatus. The plasma processing apparatus described in Patent Document 1 includes a chamber, an electrode, a high-frequency power supply, and a high-frequency bias power supply. The electrode is provided in the chamber. The substrate is placed on the electrode. The high-frequency power supply supplies high-frequency power pulses to form a high-frequency electric field in the chamber. The high-frequency bias power supply supplies high-frequency bias power pulses to the electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-64915 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for controlling the energy of ions delivered from a plasma to a substrate. [Means for solving the problem]

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a radio frequency power supply, a bias power supply, and a controller. The substrate support has a lower electrode and an electrostatic chuck. The electrostatic chuck is disposed on the lower electrode. The substrate support is configured to support a substrate placed thereon in the chamber. The radio frequency power supply is configured to generate radio frequency power to generate plasma from a gas in the chamber. The radio frequency power has a first frequency. The bias power supply is electrically connected to the lower electrode. The bias power supply is configured to apply a periodically pulsed negative polarity DC voltage to the lower electrode at a period defined by a second frequency. The second frequency is lower than the first frequency. The controller is configured to control the radio frequency power supply. The controller controls the radio frequency power supply to supply radio frequency power within a first subperiod of the period. The controller controls the radio frequency power supply to set a power level of the radio frequency power during the second subperiod of the period to a power level that is reduced from the power level of the radio frequency power during the first subperiod. [Effects of the Invention]

[0006] According to one exemplary embodiment, a technique is provided for controlling the energy of ions delivered from a plasma to a substrate. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a schematic diagram of a plasma processing apparatus according to an exemplary embodiment; [Figure 2] 10 is a timing chart of an example of high frequency power and a pulsed negative DC voltage. [Figure 3] 10 is a timing chart of high frequency power and pulsed negative DC voltage according to another example. [Figure 4] 10 is a timing chart of a pulsed negative DC voltage according to yet another example. [Figure 5] 10 is a timing chart of high frequency power according to yet another example. [Figure 6] 10 is a timing chart of high frequency power and pulsed negative DC voltage according to yet another example. [Figure 7] 10 is a timing chart of high frequency power and pulsed negative DC voltage according to yet another example. [Figure 8] Each of (a) of FIG. 8 and (b) of FIG. 8 is a timing chart of a pulsed negative DC voltage according to yet another example. [Figure 9] 1 is a flow chart illustrating a plasma processing method according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Various exemplary embodiments are described below.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a radio frequency power supply, a bias power supply, and a controller. The substrate support has a lower electrode and an electrostatic chuck. The electrostatic chuck is disposed on the lower electrode. The substrate support is configured to support a substrate placed thereon in the chamber. The radio frequency power supply is configured to generate radio frequency power to generate plasma from a gas in the chamber. The radio frequency power has a first frequency. The bias power supply is electrically connected to the lower electrode. The bias power supply is configured to apply a periodically pulsed negative polarity DC voltage to the lower electrode at a period defined by a second frequency. The second frequency is lower than the first frequency. The controller is configured to control the radio frequency power supply. The controller controls the radio frequency power supply to supply radio frequency power within a first subperiod of the period. The controller controls the radio frequency power supply to set a power level of the radio frequency power during the second subperiod of the period to a power level that is reduced from the power level of the radio frequency power during the first subperiod.

[0010] In the above embodiment, a pulsed negative DC voltage is periodically supplied to the lower electrode at a period defined by the second frequency (hereinafter referred to as the "pulse period"). The potential of the substrate fluctuates within the pulse period. In a first partial period within the pulse period, high-frequency power is supplied having a power level higher than the power level of the high-frequency power in a second partial period within the pulse period. Therefore, the energy of ions supplied to the substrate depends on the time range settings of the first partial period and the second partial period within the pulse period. Therefore, according to the above embodiment, it is possible to control the energy of ions supplied from the plasma to the substrate.

[0011] In one exemplary embodiment, the first partial period may be a period during which a pulsed negative DC voltage is applied to the lower electrode. The second partial period may be a period during which a pulsed negative DC voltage is not applied to the lower electrode. According to this embodiment, ions having relatively high energy can be supplied to the substrate.

[0012] In one exemplary embodiment, the first partial period may be a period during which a pulsed negative DC voltage is not applied to the lower electrode. The second partial period may be a period during which a pulsed negative DC voltage is applied to the lower electrode. According to this embodiment, ions having relatively low energy can be supplied to the substrate.

[0013] In one exemplary embodiment, the control unit may control the high frequency power supply to stop supplying high frequency power during the second partial period, i.e., the control unit may control the high frequency power supply to periodically supply pulses of high frequency power with a pulse period.

[0014] In one exemplary embodiment, the controller may control the radio frequency power source to periodically supply pulses of radio frequency power during the first sub-period.

[0015] In one exemplary embodiment, the frequency defining the period at which pulses of high frequency power are supplied within the first sub-period may be greater than or equal to twice the second frequency and less than or equal to 0.5 times the first frequency.

[0016] In another exemplary embodiment, a plasma processing method is provided. The plasma processing apparatus used in the plasma processing method includes a chamber, a substrate support, a radio frequency power supply, and a bias power supply. The substrate support has a lower electrode and an electrostatic chuck. The electrostatic chuck is disposed on the lower electrode. The substrate support is configured to support a substrate placed thereon in the chamber. The radio frequency power supply is configured to generate radio frequency power to generate plasma from a gas in the chamber. The radio frequency power has a first frequency. The bias power supply is electrically connected to the lower electrode. The plasma processing method is performed to perform plasma processing on a substrate placed on the electrostatic chuck. The plasma processing method includes periodically applying a pulsed negative polarity DC voltage from the bias power supply to the lower electrode at a period (i.e., a pulse period) defined by a second frequency. The second frequency is lower than the first frequency. The plasma processing method further includes supplying radio frequency power from the radio frequency power supply within a first partial period within the period. The plasma processing method further includes setting the power level of the high frequency power in the second partial period within the cycle to a power level that is reduced from the power level of the high frequency power in the first partial period.

[0017] In one exemplary embodiment, the first partial period may be a period during which a pulsed negative DC voltage is applied to the lower electrode, and the second partial period may be a period during which a pulsed negative DC voltage is not applied to the lower electrode.

[0018] In one exemplary embodiment, the first partial period may be a period during which a pulsed negative DC voltage is not applied to the lower electrode, and the second partial period may be a period during which a pulsed negative DC voltage is applied to the lower electrode.

[0019] In one exemplary embodiment, the supply of high frequency power may be stopped during the second sub-period.

[0020] In one exemplary embodiment, pulses of radio frequency power may be provided periodically during the first sub-period from the radio frequency power source.

[0021] In one exemplary embodiment, the frequency defining the period at which pulses of high frequency power are supplied within the first sub-period may be greater than or equal to twice the second frequency and less than or equal to 0.5 times the first frequency.

[0022] In one exemplary embodiment, the plasma processing method may further include applying a pulsed negative DC voltage from a bias power supply to the lower electrode periodically at the pulse period during the period when plasma exists in the chamber. This period has a time length longer than the time length of the period defined by the second frequency. During this period, the supply of high frequency power from the high frequency power supply is stopped.

[0023] In one exemplary embodiment, the plasma processing method may further include supplying high-frequency power from the high-frequency power supply during a period longer than the time length of the pulse period, during which application of the pulsed negative DC voltage from the bias power supply to the lower electrode is stopped.

[0024] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0025] FIG. 1 is a diagram schematically illustrating a plasma processing apparatus according to an exemplary embodiment. The plasma processing apparatus 1 illustrated in FIG. 1 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The central axis of the internal space 10s is an axis AX extending in the vertical direction.

[0026] In one embodiment, the chamber 10 includes a chamber body 12. The chamber body 12 has a generally cylindrical shape. An internal space 10s is provided within 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, i.e., the wall surface defining the internal space 10s. This film may be a film formed by anodizing or a ceramic film such as a film formed from yttrium oxide.

[0027] A passage 12p is formed in the sidewall 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 sidewall of the chamber body 12 to open and close the passage 12p.

[0028] The plasma processing apparatus 1 further includes a substrate support 16. The substrate support 16 is configured to support a substrate W placed thereon in the chamber 10. The substrate W has a substantially disk shape. The substrate support 16 is supported by a support portion 17. The support portion 17 extends upward from the bottom of the chamber body 12. The support portion 17 has a substantially cylindrical shape. The support portion 17 is made of an insulating material such as quartz.

[0029] The substrate support 16 has a lower electrode 18 and an electrostatic chuck 20. The lower electrode 18 and the electrostatic chuck 20 are provided in the chamber 10. The lower electrode 18 is made of a conductive material such as aluminum and has a generally disk shape.

[0030] A flow path 18f is formed in the lower electrode 18. The flow path 18f is a flow path for a heat exchange medium. As the heat exchange medium, a liquid refrigerant or a refrigerant (e.g., chlorofluorocarbon) that cools the lower electrode 18 by vaporizing is used. A heat exchange medium supply device (e.g., a chiller unit) is connected to the flow path 18f. This supply device is provided outside the chamber 10. The heat exchange medium is supplied to the flow path 18f from the supply device via a pipe 23a. The heat exchange medium supplied to the flow path 18f is returned to the supply device via a pipe 23b.

[0031] The electrostatic chuck 20 is provided on the lower electrode 18. The substrate W is placed on and held by the electrostatic chuck 20 when being processed in the internal space 10s.

[0032] The electrostatic chuck 20 has a body and an electrode. The body of the electrostatic chuck 20 is formed from a dielectric material such as aluminum oxide or aluminum nitride. The body of the electrostatic chuck 20 has a substantially disk shape. The central axis of the electrostatic chuck 20 substantially coincides with the axis AX. The electrode of the electrostatic chuck 20 is provided within the body. The electrode of the electrostatic chuck 20 has a film shape. A DC power supply is electrically connected to the electrode of the electrostatic chuck 20 via a switch. When a voltage from the DC power supply is applied to the electrode of the electrostatic chuck 20, an electrostatic attractive force is generated between the electrostatic chuck 20 and the substrate W. The generated electrostatic attractive force attracts the substrate W to the electrostatic chuck 20, and the substrate W is held by the electrostatic chuck 20.

[0033] The electrostatic chuck 20 includes a substrate mounting area. The substrate mounting area is a substantially disk-shaped area. The central axis of the substrate mounting area substantially coincides with the axis AX. When the substrate W is processed in the chamber 10, it is placed on the upper surface of the substrate mounting area.

[0034] In one embodiment, the electrostatic chuck 20 may further include an edge ring mounting region. The edge ring mounting region extends circumferentially around the central axis of the electrostatic chuck 20 to surround the substrate mounting region. An edge ring ER is mounted on the upper surface of the edge ring mounting region. The edge ring ER has an annular shape. The edge ring ER is mounted on the edge ring mounting region so that its central axis coincides with the axis AX. The substrate W is disposed within the region surrounded by the edge ring ER. That is, the edge ring ER is disposed so as to surround the edge of the substrate W. The edge ring ER may be electrically conductive. The edge ring ER is formed of, for example, silicon or silicon carbide. The edge ring ER may also be formed of a dielectric material such as quartz.

[0035] 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 to the gap between the upper surface of the electrostatic chuck 20 and the rear surface (lower surface) of the substrate W.

[0036] The plasma processing apparatus 1 may further include an insulating region 27. The insulating region 27 is disposed on the support portion 17. The insulating region 27 is disposed radially outward from the lower electrode 18 relative to the axis AX. The insulating region 27 extends in the circumferential direction along the outer circumferential surface of the lower electrode 18. The insulating region 27 is made of an insulator such as quartz. The edge ring ER is mounted on the insulating region 27 and the edge ring mounting region.

[0037] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 16. The upper electrode 30 closes the upper opening of the chamber body 12 together with a member 32. The member 32 has insulating properties. The upper electrode 30 is supported on the upper part of the chamber body 12 via this member 32.

[0038] The upper electrode 30 includes a top plate 34 and a support 36. The lower surface of the top plate 34 defines an internal space 10s. A plurality of gas discharge holes 34a are formed in the top plate 34. Each of the plurality of gas discharge holes 34a penetrates the top plate 34 in the thickness direction (vertical direction). The top plate 34 is made of, for example, silicon, but is not limited thereto. Alternatively, the top plate 34 may have a structure in which a plasma-resistant film is provided on the surface of an aluminum member. This film may be a ceramic film, such as a film formed by anodizing or a film formed from yttrium oxide.

[0039] The support 36 detachably supports the top plate 34. The support 36 is made of a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support 36. A plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are respectively connected to the plurality of gas discharge holes 34a. A gas introduction port 36c is formed in the support 36. The gas introduction port 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas introduction port 36c.

[0040] A gas source group 40 is connected to the gas supply pipe 38 via a valve group 41, a flow rate controller group 42, and a valve group 43. The gas source group 40, the valve group 41, the flow rate controller group 42, and the valve group 43 constitute a gas supply unit. The gas source group 40 includes a plurality of gas sources. Each of the valve group 41 and the valve group 43 includes a plurality of valves (e.g., on-off valves). The flow rate controller group 42 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers in the flow rate controller group 42 is a mass flow controller or a pressure-controlled flow rate controller. Each of the plurality of gas sources in the gas source group 40 is connected to the gas supply pipe 38 via a corresponding valve in the valve group 41, a corresponding flow rate controller in the flow rate controller group 42, and a corresponding valve in the valve group 43. The plasma processing apparatus 1 can supply gas from one or more selected gas sources of the gas source group 40 to the internal space 10s at individually adjusted flow rates.

[0041] A baffle plate 48 is provided between the substrate support 16 or the support portion 17 and the side wall of the chamber body 12. The baffle plate 48 can be formed, for example, by coating an aluminum member with a ceramic such as yttrium oxide. A large number of through-holes are formed in the baffle plate 48. Below the baffle plate 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 has a pressure controller such as an automatic pressure control valve and a vacuum pump such as a turbomolecular pump, and is able to reduce the pressure in the internal space 10s.

[0042] The plasma processing apparatus 1 further includes a high-frequency power supply 61. The high-frequency power supply 61 is a power supply that generates high-frequency power RF. The high-frequency power RF is used to generate plasma from the gas in the chamber 10. The high-frequency power RF has a first frequency. The first frequency is a frequency within a range of 27 to 100 MHz, for example, a frequency of 40 MHz or 60 MHz. The high-frequency power supply 61 is connected to the lower electrode 18 via a matching circuit 63 in order to supply the high-frequency power RF to the lower electrode 18. The matching circuit 63 is configured to match the output impedance of the high-frequency power supply 61 with the impedance on the load side (lower electrode 18 side). Note that the high-frequency power supply 61 does not necessarily have to be electrically connected to the lower electrode 18, and may be connected to the upper electrode 30 via the matching circuit 63.

[0043] The plasma processing apparatus 1 further includes a bias power supply 62. The bias power supply 62 is electrically connected to the lower electrode 18. In one embodiment, the bias power supply 62 is electrically connected to the lower electrode 18 via a low-pass filter 64. The bias power supply 62 generates a pulse having a period P defined by a second frequency. P That is, a negative polarity DC voltage PV is applied to the lower electrode 18 periodically in a pulse period. The second frequency is lower than the first frequency. The second frequency is, for example, not less than 50 kHz and not more than 27 MHz.

[0044] When plasma processing is performed in the plasma processing apparatus 1, gas is supplied to the internal space 10s. Then, high-frequency power RF is supplied, exciting the gas in the internal space 10s. As a result, plasma is generated in the internal space 10s. A substrate W supported by the substrate support 16 is processed by chemical species such as ions and radicals from the plasma. For example, the substrate is etched by the chemical species from the plasma. In the plasma processing apparatus 1, a pulsed negative DC voltage PV is applied to the lower electrode 18, accelerating ions from the plasma toward the substrate W.

[0045] The plasma processing apparatus 1 further includes a control unit MC. The control unit MC is a computer equipped with a processor, a storage device, an input device, a display device, etc., and controls each part of the plasma processing apparatus 1. The control unit MC executes a control program stored in the storage device and controls each part of the plasma processing apparatus 1 based on recipe data stored in the storage device. Under the control of the control unit MC, a process specified by the recipe data is executed in the plasma processing apparatus 1. A plasma processing method, which will be described later, can be executed in the plasma processing apparatus 1 under the control of each part of the plasma processing apparatus 1 by the control unit MC.

[0046] The control unit MC is P The control unit MC controls the high frequency power supply 61 to supply high frequency power RF during at least a part of the first partial period P1 within the period P. In the plasma processing apparatus 1, the high frequency power RF is supplied to the lower electrode 18. Alternatively, the high frequency power RF may be supplied to the upper electrode 30. The control unit MC controls the high frequency power RF during at least a part of the first partial period P1 within the period P. P The power level of the radio frequency power RF in the second partial period P2 within the first partial period P1 is set to a power level that is reduced from the power level of the radio frequency power RF in the first partial period P1. That is, the control unit MC controls the radio frequency power supply 61 to supply one or more pulses PRF of the radio frequency power RF in the first partial period P1.

[0047] The power level of the radio frequency power RF in the second partial period P2 may be 0 [W]. That is, the control unit MC may control the radio frequency power supply 61 to stop the supply of the radio frequency power RF in the second partial period P2. Alternatively, the power level of the radio frequency power RF in the second partial period P2 may be greater than 0 [W].

[0048] The control unit MC is configured to provide a synchronization pulse, a delay time length, and a supply time length to the high frequency power supply 61. The synchronization pulse is synchronized with the pulsed negative DC voltage PV. The delay time length is determined by the period P specified by the synchronization pulse. P The supply time length is the length of time for which the high frequency power RF is supplied. The high frequency power supply 61 supplies the high frequency power RF in the period P P One or more pulses PRF of radio frequency power RF are supplied for the supply time length from a time point delayed by the delay time length from the start of the first partial period P1. As a result, radio frequency power RF is supplied to the lower electrode 18 during the first partial period P1. Note that the delay time length may be zero.

[0049] In one embodiment, the plasma processing apparatus 1 may further include a voltage sensor 78. The voltage sensor 78 is configured to directly or indirectly measure the potential of the substrate W. In the example shown in Fig. 1, the voltage sensor 78 is configured to measure the potential of the lower electrode 18. Specifically, the voltage sensor 78 measures the potential of a power supply path connected between the lower electrode 18 and the bias power supply 62.

[0050] The control unit MC determines whether the potential of the substrate W measured by the voltage sensor 78 changes with a period P P The average potential V of the substrate W at AVE The control unit MC may determine a period during which the potential of the substrate W measured by the voltage sensor 78 is higher or lower than the average value V as the first partial period P1. AVE The second partial period P2 may be determined to be a period in which the potential of the substrate W is lower or higher than the average value V AVEmay be a predetermined value. The control unit MC may control the high frequency power supply 61 to supply the high frequency power RF as described above during the determined first partial period P1. The control unit MC may also control the high frequency power supply 61 to set the power level of the high frequency power RF as described above during the determined second partial period P2.

[0051] In the plasma processing apparatus 1, a pulsed negative DC voltage PV is applied with a period P P is periodically supplied to the lower electrode 18, so that the potential of the substrate W is P It fluctuates within the period P P In the first partial period P1 in the period P P The radio frequency power RF is supplied at a power level higher than the power level of the radio frequency power RF in the second partial period P2 within the period P. Therefore, the energy of the ions supplied to the substrate W is P The energy of the ions supplied from the plasma to the substrate W depends on the time ranges set for the first partial period P1 and the second partial period P2 within the plasma processing apparatus 1. Therefore, the plasma processing apparatus 1 makes it possible to control the energy of the ions supplied from the plasma to the substrate W.

[0052] FIG. 2 is a timing chart of the radio frequency power and the pulsed negative DC voltage according to an example. In FIG. 2, "VO" indicates the output voltage of the bias power supply 62, and "RF" indicates the power level of the radio frequency power RF. In the example shown in FIG. 2, a first partial period P1 is a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18. In the example shown in FIG. 2, a second partial period P2 is a period during which the pulsed negative DC voltage PV is not applied to the lower electrode 18. In the example shown in FIG. 2, one pulse PRF of the radio frequency power RF is supplied in the first partial period P1. According to this example, ions having relatively high energy can be supplied to the substrate W.

[0053] FIG. 3 is a timing chart of the radio frequency power and the pulsed negative DC voltage according to another example. In FIG. 3, "VO" indicates the output voltage of the bias power supply 62, and "RF" indicates the power level of the radio frequency power RF. In the example shown in FIG. 3, a first partial period P1 is a period during which the pulsed negative DC voltage PV is not applied to the lower electrode 18. In the example shown in FIG. 3, a second partial period P2 is a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18. In the example shown in FIG. 3, one pulse PRF of the radio frequency power RF is supplied in the first partial period P1. According to this example, ions having relatively low energy can be supplied to the substrate W.

[0054] FIG. 4 is a timing chart of a pulsed negative DC voltage according to another example. In FIG. 4, "VO" represents the output voltage of the bias power supply 62. As shown in FIG. 4, the voltage level of the pulsed negative DC voltage PV may change during the period in which it is applied to the lower electrode 18. In the example shown in FIG. 4, the voltage level of the pulsed negative DC voltage PV decreases during the period in which it is applied to the lower electrode 18. That is, in the example shown in FIG. 4, the absolute value of the voltage level of the pulsed negative DC voltage PV increases during the period in which it is applied to the lower electrode 18. Note that the pulsed negative DC voltage PV may be applied to the lower electrode 18 during the first partial period P1 or the second partial period P2.

[0055] FIG. 5 is a timing chart of radio frequency power according to yet another example. In FIG. 5, "RF" indicates the power level of radio frequency power RF. As shown in FIG. 5, the control unit MC may control the radio frequency power supply 61 to sequentially supply a plurality of pulses PRF of radio frequency power RF in the first partial period P1. That is, the control unit MC may control the radio frequency power supply 61 to supply a pulse group PG including a plurality of pulses PRF in the first partial period P1. The pulses PRF of radio frequency power RF may be supplied periodically in the first partial period P1. The period P in which the pulses PRF of radio frequency power RF are supplied in the first partial period P1 may be set to 1 / 2. RFG may be greater than or equal to twice the second frequency and less than or equal to 0.5 times the first frequency.

[0056] 6 is a timing chart of the high frequency power and the pulsed negative DC voltage according to another example. In FIG. 6, "VO" indicates the output voltage of the bias power supply 62, and "RF" indicates the power level of the high frequency power RF. The plasma processing apparatus 1 performs the high frequency power supplying operation during the period P A In this case, a pulsed negative DC voltage PV is applied with a period P P is applied to the lower electrode 18 periodically with a period P P As shown in FIG. 6, the control unit MC supplies one or more pulses PRF of radio frequency power RF within another period P B In the period P B In this state, the control unit MC performs the operation in the period P P The bias power supply 62 may be controlled so as to periodically apply a pulsed negative DC voltage PV to the lower electrode 18 during the period P B is the period P P The period P has a time length longer than the time length of the period P. B may be the period during which plasma exists in the chamber 10. B For example, in the period P A It may be a period following.

[0057] 7 is a timing chart of the high frequency power and the pulsed negative DC voltage according to another example. In FIG. 7, "VO" indicates the output voltage of the bias power supply 62, and "RF" indicates the power level of the high frequency power RF. As shown in FIG. 7, the control unit MC controls the high frequency power and the negative DC voltage in another period P C During the period P C In the period P, the control unit MC may control the high frequency power supply 61 to supply high frequency power RF while the application of the pulsed negative DC voltage PV to the lower electrode 18 is stopped. C In the period P C The period P of the supply of the pulse PRF or pulse group PG of the radio frequency power RF in RFC is the period P A The period of supply of the pulse PRF or pulse group PG of the radio frequency power RF in P The period P C Even in this case, the period P of the supply of the pulses PRF of the radio frequency power RF forming the pulse group PG RFG may be greater than or equal to twice the second frequency and less than or equal to 0.5 times the first frequency.

[0058] 8(a) and 8(b) are timing charts of a pulsed negative DC voltage according to another example. The output voltage V0 of the bias power supply 62 in the example shown in FIG. 8(a) differs from the output voltage V0 of the bias power supply 62 in the example shown in FIG. 2 in that its polarity is changed to positive within the second partial period P2 and immediately before the first partial period P1. That is, in the example shown in FIG. 8(a), a positive DC voltage is applied from the bias power supply 62 to the lower electrode 18 within the second partial period P2 and immediately before the first partial period P1. Note that when a pulsed negative DC voltage V0 is applied to the lower electrode 18 within the first partial period P1, a positive DC voltage may be applied from the bias power supply 62 to the lower electrode 18 during at least a part of the second partial period P2.

[0059] 8(b) differs from the output voltage VO of the bias power supply 62 in the example shown in Fig. 3 in that its polarity is changed to positive within the first partial period P1 and immediately before the second partial period P2. That is, in the example shown in Fig. 8(b), a positive DC voltage is applied from the bias power supply 62 to the lower electrode 18 within the first partial period P1 and immediately before the second partial period P2. Note that when a pulsed negative DC voltage PV is applied to the lower electrode 18 within the second partial period P2, a positive DC voltage may be applied from the bias power supply 62 to the lower electrode 18 during at least a part of the first partial period P1.

[0060] Reference is now made to Fig. 9, which is a flow chart illustrating a plasma processing method according to one exemplary embodiment. The plasma processing method illustrated in Fig. 9 (hereinafter referred to as "method MT") can be performed using the plasma processing apparatus 1 described above.

[0061] The method MT is performed in a state where a substrate W is placed on the electrostatic chuck 20. The method MT is performed to perform plasma processing on the substrate W. In the method MT, a gas is supplied from a gas supply unit into the chamber 10. Then, the pressure of the gas in the chamber 10 is set to a specified pressure by the exhaust device 50.

[0062] In the method MT, step ST1 is performed. In step ST1, a pulsed negative DC voltage PV is applied from the bias power supply 62 to the lower electrode 18 with a period P P is applied periodically.

[0063] The process ST2 has a period P P The step ST3 is performed in a first partial period P1 within the period P P The first partial period P1 may be a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18. The second partial period P2 may be a period during which the pulsed negative DC voltage PV is not applied to the lower electrode 18. Alternatively, the first partial period P1 may be a period during which the pulsed negative DC voltage PV is not applied to the lower electrode 18. The second partial period P2 may be a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18.

[0064] In step ST2, high frequency power RF is supplied from the high frequency power supply 61 to generate plasma. In the first partial period P1, one or more pulses PRF of high frequency power RF may be supplied. In the first partial period P1, multiple pulses PRF of high frequency power RF may be supplied sequentially. That is, in the first partial period P1, a pulse group PG including multiple pulses PRF may be supplied. In the first partial period P1, the pulses PRF of high frequency power RF may be supplied periodically. The period P in which the pulses PRF of high frequency power RF are supplied in the first partial period P1 may be set to 1. RFG may be greater than or equal to twice the second frequency and less than or equal to 0.5 times the first frequency.

[0065] In the process ST3, the period P P The power level of the radio frequency power RF in the second partial period P2 within the first partial period P1 is set to a power level that is reduced from the power level of the radio frequency power RF in the first partial period P1. The supply of the radio frequency power RF may be stopped in the second partial period P2.

[0066] The steps ST1 to ST3 are performed during the above-mentioned period P A In the method MT, the period P B 6, in a state where the supply of high frequency power RF from the high frequency power supply 61 is stopped, P A pulsed negative DC voltage PV may be applied periodically from the bias power supply 62 to the lower electrode 18 during the period P B is the period P P The period P has a time length longer than the time length of the period P. B may be the period during which plasma exists in the chamber 10. B For example, in the period P A It may be a period following.

[0067] In method MT, another period P C In the period P (see FIG. 7), the high frequency power RF may be supplied from the high frequency power supply 61 while the application of the pulsed negative DC voltage PV from the bias power supply 62 to the lower electrode 18 is stopped. C In the period P, the control unit MC may control the high frequency power supply 61 to supply high frequency power RF while the application of the pulsed negative DC voltage PV to the lower electrode 18 is stopped. C During the period P, a pulse PRF or a pulse group PG of radio frequency power RF may be periodically supplied from the radio frequency power supply 61. C The period P of the supply of the pulse PRF or pulse group PG of the radio frequency power RF in RFC is the period P A The period of supply of the pulse PRF or pulse group PG of the radio frequency power RF in P The period P C Even in this case, the period P of the supply of the pulses PRF of the radio frequency power RF forming the pulse group PG RFG may be greater than or equal to twice the second frequency and less than or equal to 0.5 times the first frequency.

[0068] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0069] The plasma processing apparatus according to another embodiment may be a capacitively coupled plasma processing apparatus different from the plasma processing apparatus 1. Furthermore, the plasma processing apparatus according to yet another embodiment may be an inductively coupled plasma processing apparatus. Furthermore, the plasma processing apparatus according to yet another embodiment may be an ECR (electron cyclotron resonance) plasma processing apparatus. Furthermore, the plasma processing apparatus according to yet another embodiment may be a plasma processing apparatus that generates plasma using surface waves such as microwaves.

[0070] Also, the period P P The period P may be composed of three or more sub-periods including a first sub-period P1 and a second sub-period P2. P The time lengths of the three or more partial periods may be the same as or different from one another. The power level of the radio frequency power RF in each of the three or more partial periods may be set to a power level different from the power levels of the radio frequency power RF in the preceding and following partial periods.

[0071] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0072] 1...plasma processing apparatus, 10...chamber, 16...substrate support, 18...lower electrode, 20...electrostatic chuck, 61...high frequency power supply, 62...bias power supply, MC...control unit.

Claims

1. a chamber; a substrate support configured to support a substrate placed thereon in the chamber, the substrate support having a lower electrode and an electrostatic chuck disposed on the lower electrode; a radio frequency power supply configured to generate radio frequency power supplied to generate a plasma from gas in the chamber, the radio frequency power having a first frequency; a bias power supply electrically connected to the lower electrode and configured to periodically apply a pulsed DC voltage to the lower electrode at a period defined by a second frequency lower than the first frequency; a control unit configured to control the high frequency power source; Equipped with the control unit controls the high frequency power source to supply the high frequency power in a first partial period within the cycle, and to set a power level of the high frequency power in a second partial period within the cycle to a power level that is reduced from the power level of the high frequency power in the first partial period; the bias power supply is configured to increase the absolute value of the voltage level of the pulsed DC voltage during a period in which the pulsed DC voltage is applied to the lower electrode. Plasma processing equipment.

2. the first partial period is a period during which the pulsed DC voltage is applied to the lower electrode, the second partial period is a period during which the pulsed DC voltage is not applied to the lower electrode; The plasma processing apparatus according to claim 1 .

3. the first partial period is a period during which the pulsed DC voltage is not applied to the lower electrode, the second partial period is a period during which the pulsed DC voltage is applied to the lower electrode; The plasma processing apparatus according to claim 1 .

4. 4. The plasma processing apparatus according to claim 1, wherein the control unit controls the high frequency power supply to stop supplying the high frequency power during the second partial period.

5. 5. The plasma processing apparatus according to claim 1, wherein the control unit controls the high frequency power supply so as to periodically supply pulses of the high frequency power during the first partial period.

6. 6. The plasma processing apparatus according to claim 5, wherein a frequency defining a period in which the pulses of the high frequency power are supplied during the first partial period is equal to or greater than twice the second frequency and equal to or less than 0.5 times the first frequency.

7. A plasma processing method using a plasma processing apparatus, comprising: The plasma processing apparatus comprises: a chamber; a substrate support configured to support a substrate placed thereon in the chamber, the substrate support having a lower electrode and an electrostatic chuck disposed on the lower electrode; a radio frequency power supply configured to generate radio frequency power supplied to generate a plasma from gas in the chamber, the radio frequency power having a first frequency; a bias power supply electrically connected to the lower electrode; Equipped with The plasma processing method is carried out to perform plasma processing on a substrate while the substrate is placed on the electrostatic chuck, applying a pulsed DC voltage from the bias power supply to the lower electrode periodically at a period defined by a second frequency lower than the first frequency; supplying the high frequency power from the high frequency power source within a first sub-period of the cycle; setting the power level of the high frequency power within a second sub-period of the cycle to a power level that is reduced from the power level of the high frequency power within the first sub-period; Including, In the step of applying a pulsed DC voltage, the bias power supply increases the absolute value of the voltage level of the pulsed DC voltage during a period in which the pulsed DC voltage is applied to the lower electrode. Plasma treatment method.

8. the first partial period is a period during which the pulsed DC voltage is applied to the lower electrode, the second partial period is a period during which the pulsed DC voltage is not applied to the lower electrode; The plasma processing method according to claim 7 .

9. the first partial period is a period during which the pulsed DC voltage is not applied to the lower electrode, the second partial period is a period during which the pulsed DC voltage is applied to the lower electrode; The plasma processing method according to claim 7 .

10. 10. The plasma processing method according to claim 7, wherein the supply of the high frequency power is stopped during the second partial period.

11. 11. The plasma processing method according to claim 7, wherein pulses of the high frequency power are periodically supplied from the high frequency power supply during the first partial period.

12. 12. The plasma processing method according to claim 11, wherein a frequency defining a period in which the pulses of the high frequency power are supplied during the first partial period is equal to or greater than twice the second frequency and equal to or less than 0.5 times the first frequency.

13. 13. The plasma processing method according to claim 7, further comprising the step of periodically applying the pulsed DC voltage from the bias power supply to the lower electrode at the period defined by the second frequency while the supply of the high frequency power from the high frequency power supply is stopped during a period in which plasma exists in the chamber and which has a time length longer than the time length of the period defined by the second frequency.

14. 14. The plasma processing method according to claim 7, further comprising the step of supplying the high frequency power from the high frequency power supply during a period having a time length longer than a time length of the cycle defined by the second frequency, while stopping application of the pulsed DC voltage from the bias power supply to the lower electrode.

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