Plasma processing apparatus, plasma processing method, and storage medium

Abstract

To provide a technique of reducing the power level of a reflection wave from a load of a high-frequency power source.SOLUTION: The plasma processor disclosed herein includes a chamber, a substrate supporting unit, a high-frequency power source, a bias power source, and a control unit. The bias power source is formed to regularly apply a pulse-like negative DV voltage to a lower electrode of the substrate supporting unit. The control unit is formed to control the high-frequency power source. The control unit controls the high-frequency power source to supply a high-frequency power of which frequency changes within the cycles of application of the pulse-like negative DC voltage from a bias power source on the lower electrode to reduce the power level of a reflection wave from a load of the high-frequency power source.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 a technique for reducing the power level of a reflected wave from a load of a high frequency power supply. [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 supplied to generate plasma from a gas in the chamber. The bias power supply is electrically connected to the lower electrode and configured to periodically apply a pulsed negative DC voltage to the lower electrode. The controller is configured to control the radio frequency power supply. The controller controls the radio frequency power supply to supply radio frequency power whose frequency changes within a period of application of the pulsed negative DC voltage from the bias power supply to the lower electrode in order to reduce the power level of a reflected wave from a load of the radio frequency power supply. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to reduce the power level of a reflected wave from a load of a high frequency power supply. [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 a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 3] 10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 4] 10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 5] 10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 6]10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 7] 10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 8] 10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 9] 10 is a timing chart of an example of a pulsed negative DC voltage, a power of high frequency power, and a frequency of high frequency power. [Figure 10] 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 supplied to generate plasma from a gas in the chamber. The bias power supply is electrically connected to the lower electrode and configured to periodically apply a pulsed negative DC voltage to the lower electrode. The controller is configured to control the radio frequency power supply. The controller controls the radio frequency power supply to supply radio frequency power whose frequency changes within a period of application of the pulsed negative DC voltage from the bias power supply to the lower electrode in order to reduce the power level of a reflected wave from a load of the radio frequency power supply.

[0010] Reflection from a load of a high-frequency power supply occurs due to the difference between the output impedance of the high-frequency power supply and the load impedance. The difference between the output impedance of the high-frequency power supply and the load impedance can be reduced by changing the frequency of the high-frequency power. Therefore, according to the above embodiment, it is possible to reduce the power level of the reflected wave from the load of the high-frequency power supply. Furthermore, the load impedance fluctuates within the period of application of the pulsed negative DC voltage, i.e., within the pulse period. Generally, a high-frequency power supply can change the frequency of the high-frequency power faster than the impedance change rate of a matching box. Therefore, according to the above embodiment, it is possible to quickly change the frequency of the high-frequency power so as to reduce the power level of the reflected wave within the period in accordance with the fluctuation of the load impedance.

[0011] In one exemplary embodiment, the control unit may control the high frequency power source to supply high frequency power during at least a portion of a first partial period within the period, and the control unit may control the high frequency power source to set a power level of the high frequency power during a second partial period within the period to a power level that is reduced from the power level of the high frequency power during the first partial period.

[0012] 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.

[0013] 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.

[0014] In one exemplary embodiment, the control unit may control the high-frequency power source to change the frequency of the high-frequency power according to the phase within the period in order to reduce the power level of the reflected wave within the period. The control unit may control the high-frequency power source to change the frequency of the high-frequency power according to the phase within the period using a predetermined relationship between the phase within the period and the frequency of the high-frequency power in order to reduce the power level of the reflected wave within the period.

[0015] 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 provided 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 gas in the chamber. 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 a step of periodically applying a pulsed negative DC voltage from the bias power supply to the lower electrode. The plasma processing method includes a step of supplying radio frequency power whose frequency changes within a period of application of the pulsed negative DC voltage from the bias power supply to the lower electrode in order to reduce the power level of a reflected wave from a load of the radio frequency power supply.

[0016] In one exemplary embodiment, high frequency power may be supplied during at least a portion of a first subperiod within a cycle, and the power level of the high frequency power during a second subperiod within the cycle may be set to a power level that is reduced from the power level of the high frequency power during the first subperiod.

[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 frequency of the high frequency power may be changed according to the phase within the period to reduce the power level of the reflected wave within the period. The frequency of the high frequency power may be changed according to the phase within the period using a predetermined relationship between the phase within the period and the frequency of the high frequency power to reduce the power level of the reflected wave within the period.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 or alumina.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The plasma processing apparatus 1 further includes a radio frequency power supply 61. The radio frequency power supply 61 generates radio frequency power RF. The radio frequency power RF is used to generate plasma from the gas in the chamber 10. The frequency of the radio frequency power RF may be in the range of 27 to 100 MHz. The radio frequency power supply 61 is connected to the lower electrode 18 via a matching circuit 63 to supply the radio frequency power RF to the lower electrode 18. The matching circuit 63 is configured to match the output impedance of the radio frequency power supply 61 with the impedance on the load side (e.g., the lower electrode 18 side), i.e., the load impedance. The radio frequency power supply 61 may further be electrically connected to the lower electrode 18 via a power sensor 65. The power sensor 65 may include a directional coupler and a reflected wave power detector. The directional coupler is configured to at least partially transmit the wave reflected from the load of the radio frequency power supply 61 to the reflected wave power detector. The reflected wave power detector is configured to detect the power level of the wave reflected from the directional coupler. The high frequency power supply 61 does not have to be electrically connected to the lower electrode 18 , and may be connected to the upper electrode 30 via a matching circuit 63 .

[0039] 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 is configured to generate a bias voltage having a period P P That is, a negative DC voltage PV having a pulsed shape is applied to the lower electrode 18 periodically with a pulse period. P The frequency that defines the period P is lower than the frequency of the radio frequency power RF. P The frequency that defines the period P is, for example, 50 kHz or more and 27 MHz or less. Pincludes a first partial period P1 and a second partial period P2. In one embodiment, the first partial period P1 may be a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18, and 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. In another embodiment, 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, and the second partial period P2 may be a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18.

[0040] 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.

[0041] 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.

[0042] In one embodiment, the control unit MC controls the period P PThe 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 supply 61 to supply 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 may be 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 may control the radio frequency power supply 61 to supply one or more pulses of the radio frequency power RF in the first partial period P1.

[0043] 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].

[0044] 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 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 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.

[0045] 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.

[0046] 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 AVE may 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. The plasma processing apparatus 1 may use a voltage sensor 78 instead of the voltage sensor 78. P The circuit may also include other sensors (eg, current sensors) capable of obtaining measurements that can be used in determining the first and second sub-periods P1 and P2.

[0047] The control unit MC controls the period P P The high frequency power supply 61 is controlled so as to supply high frequency power RF whose frequency changes within a period P P period P to reduce the power level of the reflected wave within PThe relationship between the phase in the period P and the frequency of the high frequency power RF can be obtained in advance before or during the plasma processing of the substrate W in the plasma processing apparatus 1. This relationship is stored in the storage device of the controller MC as data in the form of a function or table. The controller MC uses this relationship to control the high frequency power supply 61. This relationship is obtained by calculating the period P P The power level of the reflected wave is detected using the power sensor 65 while changing the frequency of the high frequency power RF at each phase in the period P P This can be achieved by determining the frequency of the radio frequency power RF that suppresses or minimizes the power level of the reflected wave at each phase in the

[0048] The reflection from the load of the high frequency power supply 61 occurs due to the difference between the output impedance of the high frequency power supply 61 and the load impedance. The difference between the output impedance of the high frequency power supply 61 and the load impedance can be reduced by changing the frequency of the high frequency power RF. Therefore, according to the plasma processing apparatus 1, it is possible to reduce the power level of the reflected wave from the load of the high frequency power supply 61. In addition, the period P of the application of the pulsed negative DC voltage PV P The load impedance varies within the period P. Generally, a high frequency power supply can change the frequency of the high frequency power faster than the impedance change speed of a matching box. Therefore, according to the plasma processing apparatus 1, the frequency of the high frequency power can be changed within the period P in accordance with the variation of the load impedance. P It is possible to change the frequency of the radio frequency power RF at high speed so as to reduce the power level of the reflected wave within the antenna.

[0049] Furthermore, during the period when the negative pulsed DC voltage PV is applied to the lower electrode 18, the potential difference between the plasma and the lower electrode 18 (or the substrate W) becomes relatively large. Therefore, during the period when the negative pulsed DC voltage PV is applied to the lower electrode 18, secondary electrons generated by ion collisions with the substrate W are accelerated by the large potential difference applied to the sheath on the substrate W between the plasma and the lower electrode 18, and gain large energy. Therefore, during the period when the negative pulsed DC voltage PV is applied to the lower electrode 18, the energy of the secondary electrons is relatively high, and the electron temperature in the plasma and the degree of gas dissociation in the plasma become high. On the other hand, during the period when the negative pulsed DC voltage PV is not applied to the lower electrode 18, the potential difference between the plasma and the lower electrode 18 (or the substrate W) becomes relatively low. Therefore, during the period when the negative pulsed DC voltage PV is not applied to the lower electrode 18, the potential difference accelerating the secondary electrons is small, so the energy of the secondary electrons is relatively low, and the electron temperature in the plasma and the degree of dissociation of the gas in the plasma are low. Therefore, the plasma processing apparatus 1 can control the electron temperature in the plasma and the degree of dissociation of the gas in the plasma.

[0050] 2 to 9 will be referred to below. Each of Figures 2 to 9 is a timing chart of an example of a pulsed negative DC voltage, the power of the high frequency power, and the frequency of the high frequency power. In each of Figures 2 to 9, "VO," "RF power," and "RF frequency" represent the output voltage of the bias power supply 62, the power level of the high frequency power RF, and the frequency of the high frequency power RF, respectively.

[0051] In the example shown in FIG. 2, the 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, the 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, the control unit MC PDuring the repetition of the above, the high frequency power supply 61 is controlled to continuously supply high frequency power RF to generate plasma. In the example shown in Fig. 2, during the transient period (hereinafter referred to as the "first transient period") in which the pulsed negative DC voltage PV changes from 0 [V] to a negative peak voltage, the frequency of the high frequency power RF is increased. In the example shown in Fig. 2, during the transient period (hereinafter referred to as the "second transient period") in which the pulsed negative DC voltage PV changes from the negative peak voltage to 0 [V], the frequency of the high frequency power RF is decreased. In the example shown in Fig. 2, the frequency of the high frequency power RF in the first partial period P1 is set to a frequency higher than the frequency of the high frequency power RF in the second partial period P2.

[0052] 3 is a timing chart of a pulsed negative DC voltage, the power of the radio frequency power, and the frequency of the radio frequency power according to another example. The timing chart shown in FIG. 3 differs from the timing chart shown in FIG. 2 in that the frequency of the radio frequency power RF changes even within the second partial period P2. As shown in the example of FIG. 3, the frequency of the radio frequency power RF may be changed one or more times during at least one of the first partial period P1 and the second partial period P2. That is, the frequency of the radio frequency power RF may fluctuate during at least one of the first partial period P1 and the second partial period P2.

[0053] In the example shown in FIG. 4, the first partial period P1 is a period during which a pulsed negative DC voltage PV is applied to the lower electrode 18. In the example shown in FIG. 4, the 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. 4, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF during the first partial period P1 and to stop the supply of high-frequency power RF during the second partial period P2. That is, in the example shown in FIG. 4, the control unit MC controls the high-frequency power supply 61 to supply pulses of high-frequency power RF during the first partial period P1. In the example shown in FIG. 4, the frequency of the high-frequency power RF changes so as to increase during the first transient period. In the example shown in FIG. 4, the frequency of the high-frequency power RF changes so as to decrease during the second transient period.

[0054] In the example shown in FIG. 5, the first partial period P1 is a period during which a pulsed negative DC voltage PV is applied to the lower electrode 18. In the example shown in FIG. 5, the 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. 5, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF during the first partial period P1. In the example shown in FIG. 5, the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF during the second partial period P2 to a power level greater than 0 [W] and reduced from the power level of the high-frequency power RF during the first partial period P1. In the example shown in FIG. 5, the frequency of the high-frequency power RF increases during the first transient period. In the example shown in FIG. 5, the frequency of the high-frequency power RF decreases during the second transient period. In the example shown in FIG. 5, the frequency of the high-frequency power RF during the first partial period P1 is higher than the frequency of the high-frequency power RF during the second partial period P2.

[0055] In the example shown in FIG. 6 , the first partial period P1 is a period during which a pulsed negative DC voltage PV is applied to the lower electrode 18. In the example shown in FIG. 6 , the 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. 6 , the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF in the first partial period P1. In the example shown in FIG. 6 , the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF in the second partial period P2 to a power level that is reduced from the power level of the high-frequency power RF in the first partial period P1. Also, in the example shown in FIG. 6 , the control unit MC controls the high-frequency power supply 61 to change the power level of the high-frequency power RF in the second partial period P2. In this way, the control unit MC may control the high-frequency power supply 61 to change the power level of the high-frequency power RF one or more times in at least one of the first partial period P1 and the second partial period P2.

[0056] In the example shown in FIG. 6, during the first transition period, the frequency of the radio frequency power RF changes so as to increase. In the example shown in FIG. 6, during the second transition period, the frequency of the radio frequency power RF changes so as to decrease. In the example shown in FIG. 6, the frequency of the radio frequency power RF in the first partial period P1 is higher than the frequency of the radio frequency power RF in the second partial period P2. Also, in the example shown in FIG. 6, during the period when the power of the radio frequency power RF increases, the frequency of the radio frequency power RF changes so as to increase. Also, in the example shown in FIG. 6, during the period when the power of the radio frequency power RF decreases, the frequency of the radio frequency power RF changes so as to decrease. Also, in the example shown in FIG. 6, during the period when the power of the radio frequency power RF is high, the frequency of the radio frequency power RF is higher than the frequency of the radio frequency power RF in the period when the power of the radio frequency power RF is low.

[0057] In the example shown in FIG. 7, the 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. 7, the 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. 7, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF during the first partial period P1 and to stop the supply of high-frequency power RF during the second partial period P2. That is, in the example shown in FIG. 7, the control unit MC controls the high-frequency power supply 61 to supply pulses of high-frequency power RF during the first partial period P1. In the example shown in FIG. 7, the frequency of the high-frequency power RF changes so as to increase during the first transient period. In the example shown in FIG. 7, the frequency of the high-frequency power RF changes so as to decrease during the second transient period.

[0058] In the example shown in FIG. 8 , the 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. 8 , the 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. 8 , the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF during the first partial period P1. In the example shown in FIG. 8 , the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF during the second partial period P2 to a power level greater than 0 [W] and reduced from the power level of the high-frequency power RF during the first partial period P1. In the example shown in FIG. 8 , the frequency of the high-frequency power RF increases during the first transient period. In the example shown in FIG. 8 , the frequency of the high-frequency power RF decreases during the second transient period. In the example shown in FIG. 8 , the frequency of the high-frequency power RF during the first partial period P1 is lower than the frequency of the high-frequency power RF during the second partial period P2.

[0059] In the example shown in FIG. 9 , the 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. 9 , the 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. 9 , the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF in the first partial period P1. In the example shown in FIG. 9 , the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF in the second partial period P2 to a power level that is reduced from the power level of the high-frequency power RF in the first partial period P1. Also, in the example shown in FIG. 9 , the control unit MC controls the high-frequency power supply 61 to change the power level of the high-frequency power RF in the first partial period P1. In this way, the control unit MC may control the high-frequency power supply 61 to change the power level of the high-frequency power RF one or more times in at least one of the first partial period P1 and the second partial period P2.

[0060] In the example shown in FIG. 9, the frequency of the radio frequency power RF increases during the first transition period. In the example shown in FIG. 9, the frequency of the radio frequency power RF decreases during the second transition period. In the example shown in FIG. 9, the frequency of the radio frequency power RF in the first partial period P1 is lower than the frequency of the radio frequency power RF in the second partial period P2. In the example shown in FIG. 9, the frequency of the radio frequency power RF decreases during the period in which the power of the radio frequency power RF increases. In the example shown in FIG. 9, the frequency of the radio frequency power RF increases during the period in which the power of the radio frequency power RF decreases. In the example shown in FIG. 9, the frequency of the radio frequency power RF in the period in which the power of the radio frequency power RF is high is lower than the frequency of the radio frequency power RF in the period in which the power of the radio frequency power RF is low. As in the example shown in FIG. 9, the frequency of the radio frequency power RF may be changed one or more times during at least one of the first partial period P1 and the second partial period P2. That is, the frequency of the radio frequency power RF may vary during at least one of the first partial period P1 and the second partial period P2.

[0061] Reference is now made to Fig. 10, which is a flow chart illustrating a plasma processing method according to one exemplary embodiment. The plasma processing method illustrated in Fig. 10 (hereinafter referred to as "method MT") can be performed using the plasma processing apparatus 1 described above.

[0062] 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.

[0063] 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.

[0064] Step ST2 is performed during the execution of step ST1. In step ST2, in order to reduce the power level of the reflected wave from the load of the high frequency power supply 61, P A radio frequency power RF is supplied, the frequency of which varies within a period P P For setting the frequency of the high frequency power RF according to the phase in the signal line and examples thereof, please refer to the above description and the examples in FIGS.

[0065] In one embodiment, the radio frequency power RF is applied at a period P P In one embodiment, the high frequency power supply 61 may supply the high frequency power 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 may be 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 power level of the radio frequency power RF in the second partial period P2 may be 0 [W].

[0066] In one embodiment, the first partial period P1 may be a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18, and 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. In another embodiment, 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, and the second partial period P2 may be a period during which the pulsed negative DC voltage PV is applied to the lower electrode 18.

[0067] 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.

[0068] 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.

[0069] 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 within the period may be the same 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 the same or 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.

[0070] 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]

[0071] 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 having an electrostatic chuck and configured to support a substrate disposed thereon within the chamber; a radio frequency power source configured to supply radio frequency power into the chamber; a bias power supply electrically connected to the substrate support and configured to periodically apply a voltage pulse to the substrate support with a period having a first period during which the voltage pulse is applied to the substrate support and a second period during which the voltage pulse is not applied to the substrate support; a control unit configured to control the high frequency power source; Equipped with The control unit controlling the high frequency power supply to change the frequency of the high frequency power within the first period during which the one voltage pulse is applied to the substrate support; controlling the high frequency power supply so as to continuously supply the high frequency power within the period; controlling the high frequency power supply to change the frequency of the high frequency power in accordance with the phase within the period in order to reduce the power level of the reflected wave within the period; Plasma processing equipment.

2. a chamber; a substrate support having an electrostatic chuck and configured to support a substrate disposed thereon within the chamber; a radio frequency power source configured to supply radio frequency power into the chamber; a bias power supply electrically connected to the substrate support and configured to periodically apply a voltage pulse to the substrate support with a period having a first period during which the voltage pulse is applied to the substrate support and a second period during which the voltage pulse is not applied to the substrate support; a control unit configured to control the high frequency power source; Equipped with The control unit controlling the high frequency power source to increase and decrease the frequency of the high frequency power within the period; controlling the high frequency power supply so as to continuously supply the high frequency power within the period; controlling the high frequency power supply to change the frequency of the high frequency power in accordance with the phase within the period in order to reduce the power level of the reflected wave within the period; Plasma processing equipment.

3. 3. The plasma processing apparatus according to claim 1, wherein the control unit controls the high frequency power supply so as to set a power level of the high frequency power in the second period to a power level that is reduced from a power level of the high frequency power in the first period.

4. 3. The plasma processing apparatus according to claim 1, wherein the control unit controls the high frequency power supply so as to set a power level of the high frequency power in the first period to a power level that is reduced from a power level of the high frequency power in the second period.

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

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

7. 7. The plasma processing apparatus of claim 1, wherein the control unit controls the high frequency power supply so as to change the frequency of the high frequency power during the second period.

8. The plasma processing apparatus according to claim 7 , wherein the control unit controls the high frequency power supply so as to increase the frequency of the high frequency power during the second period.

9. The plasma processing apparatus according to claim 7 , wherein the control unit controls the high frequency power supply so as to reduce the frequency of the high frequency power during the second period.

10. 10. The plasma processing apparatus according to claim 1, wherein the bias power supply applies the single voltage pulse to the substrate support at a frequency of 50 kHz or more and 27 MHz or less.

11. 11. The plasma processing apparatus according to claim 1, wherein the high frequency power supply supplies the high frequency power into the chamber at the frequency of 27 MHz to 100 MHz.

12. a chamber; a substrate support having an electrostatic chuck and configured to support a substrate disposed thereon within the chamber; a radio frequency power source configured to supply radio frequency power into the chamber; a bias power supply electrically connected to the substrate support and configured to periodically apply a voltage pulse to the substrate support with a period having a first period during which the voltage pulse is applied to the substrate support and a second period during which the voltage pulse is not applied to the substrate support; a control unit configured to control the high frequency power source; Equipped with The control unit controlling the high frequency power supply to increase the frequency of the high frequency power during the first period in which the one voltage pulse is applied to the substrate support, and then controlling the high frequency power supply to decrease the increased frequency during the first period; controlling the high frequency power supply so as to continuously supply the high frequency power within the period; the bias power supply applies the voltage pulse to the substrate support at a frequency of 50 kHz or more and 27 MHz or less; the high frequency power supply applies the high frequency power to the substrate support at the frequency of 27 MHz to 100 MHz; the control unit controls the high frequency power supply to change the frequency of the high frequency power in accordance with the phase within the period in order to reduce the power level of the reflected wave within the period. Plasma processing equipment.

13. The plasma processing apparatus according to claim 12 , wherein the control unit executes control to increase the power level of the high frequency power and control to decrease the power level of the high frequency power within the period.

14. The plasma processing apparatus according to claim 13 , wherein the control unit executes control to reduce a power level of the high frequency power during the first period.

15. The one voltage pulse is a negative pulse voltage and has a first transient period and a second transient period; the control unit is configured to increase the frequency of the high frequency power during the first transition period in which the one voltage pulse changes from 0 volts to a negative peak voltage, and to decrease the frequency of the high frequency power during the second transition period in which the one voltage pulse changes from the negative peak voltage to 0 volts. The plasma processing apparatus according to any one of claims 1 to 14.

16. A plasma processing method using a plasma processing apparatus, comprising: The plasma processing apparatus comprises: a chamber; a substrate support having an electrostatic chuck and configured to support a substrate disposed thereon within the chamber; a radio frequency power source configured to supply radio frequency power into the chamber; a bias power supply electrically connected to the substrate support and configured to periodically apply a voltage pulse to the substrate support; 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, periodically applying the one voltage pulse from the bias power supply to the substrate support in a cycle having a first period and a second period, the one voltage pulse being applied to the substrate support during the first period and not being applied to the substrate support during the second period; supplying the high frequency power; Including, the step of supplying the high frequency power includes varying a frequency of the high frequency power within the first period during which the one voltage pulse is applied to the substrate support; In the step of supplying high frequency power, the high frequency power is continuously supplied within the cycle, the frequency of the high frequency power is changed according to the phase within the period in order to reduce the power level of the reflected wave within the period; Plasma treatment method.

17. 17. The plasma processing method of claim 16, wherein a power level of the high frequency power in the second period within the cycle is set to a power level that is reduced from a power level of the high frequency power in the first period.

18. 17. The plasma processing method of claim 16, wherein a power level of the high frequency power in the first period is set to a power level that is reduced from a power level of the high frequency power in the second period.

19. 17. The plasma processing method of claim 16, wherein the frequency of the high frequency power is increased during the first period.

20. 17. The plasma processing method of claim 16, wherein the frequency of the high frequency power is decreased during the first period of time.

21. 21. The plasma processing method according to claim 16, wherein the frequency of the high frequency power is changed during the second period.

22. 22. The plasma processing method of claim 21, wherein the frequency of the radio frequency power is increased during the second period of time.

23. 22. The plasma processing method of claim 21, wherein the frequency of the radio frequency power is decreased during the second period of time.

24. 24. The plasma processing method according to claim 16, wherein the one voltage pulse is applied to the substrate support at a frequency of 50 kHz or more and 27 MHz or less.

25. 25. The plasma processing method according to claim 16, wherein the high frequency power is supplied into the chamber at a frequency of 27 MHz to 100 MHz.

26. A computer-readable storage medium storing a program for causing a plasma processing apparatus to execute the plasma processing method according to any one of claims 16 to 25.

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