Power supply system

Abstract

To improve performance of a process using a plurality of high frequency power pulse signals.SOLUTION: A first RF pulse signal includes a plurality of main cycles. Each main cycle includes a first period and a second period. The first period includes a plurality of first sub-cycles and the second period includes a plurality of second sub-cycles. The first RF pulse signal has three or more different power levels in each of the plurality of first sub-cycles and the plurality of second sub-cycles. A second RF pulse signal includes a plurality of main cycles. The second RF pulse signal has two or more different power levels in each of the plurality of first sub-cycles and has a zero power level in the second period. A third RF pulse signal includes a plurality of main cycles. The third RF pulse signal has two or more different power levels in each of the plurality of first sub-cycles and has a zero power level in the second period.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus and a plasma processing method. [Background technology]

[0002] Patent Document 1 discloses a plasma processing apparatus having two high-frequency power supplies that supply dual-frequency power to an antenna and a susceptor above a chamber. One of the two high-frequency power supplies supplies bias high-frequency power of, for example, 13 MHz to the susceptor. An antenna is provided above the chamber, and the other high-frequency power supply supplies plasma excitation high-frequency power of, for example, 27 MHz to the antenna.

[0003] Patent Document 2 discloses a plasma processing system including an SP (source power) coupling element and a BP (bias power) coupling element coupled to a plasma processing chamber. The SP coupling element is, for example, an antenna and is configured to be able to supply source power. The BP coupling element is, for example, an electrostatic chuck and is configured to be able to supply bias power. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-67503 [Patent Document 2] US Patent Application Publication No. 2020 / 0058470 Summary of the Invention [Problem to be solved by the invention]

[0005] The disclosed techniques use multiple high frequency power pulse signals to improve process performance. [Means for solving the problem]

[0006] A plasma processing apparatus according to one aspect of the present disclosure includes a plasma processing chamber, a substrate support disposed in the plasma processing chamber, an electrode disposed in the substrate support, and a first RF generator coupled to the plasma processing chamber and configured to generate a first RF pulse signal including a plurality of main cycles, each main cycle including a first period and a second period, the first period including a plurality of first sub-cycles, the second period including a plurality of second sub-cycles, and the first RF pulse signal having three or more different power levels in each of the plurality of first sub-cycles and the plurality of second sub-cycles. a second RF generator coupled to the electrode and configured to generate a second RF pulsed signal comprising the plurality of main cycles, the second RF pulsed signal having two or more different power levels in each of the plurality of first sub-cycles and having a zero power level in the second period; and a third RF generator coupled to the electrode and configured to generate a third RF pulsed signal comprising the plurality of main cycles, the third RF pulsed signal having two or more different power levels in each of the plurality of first sub-cycles and having a zero power level in the second period. [Effects of the Invention]

[0007] According to the present disclosure, multiple high frequency power pulse signals can be used to improve process performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram schematically illustrating a configuration of a plasma processing system. [Figure 2] 1 is a vertical cross-sectional view showing an outline of the configuration of a plasma processing apparatus; [Figure 3] FIG. 1 is an explanatory diagram showing an example of changes over time in radicals, ions, electron temperature (plasma electron temperature), ion energy, and by-products. [Figure 4] FIG. 10 is an explanatory diagram showing a pattern in which two RF powers are continuous waves in Comparative Example 1. [Figure 5] FIG. 10 is a cross-sectional view showing a pattern shape after etching in Comparative Example 1. [Figure 6] FIG. 10 is an explanatory diagram showing a pulse pattern of a dual-frequency RF power pulse in Comparative Example 2. [Figure 7] FIG. 10 is an explanatory diagram showing a pulse pattern of RF power pulses of two frequencies in one subcycle in Comparative Example 2. [Figure 8] FIG. 10 is a cross-sectional view showing a pattern shape after etching in Comparative Example 2. [Figure 9] FIG. 3 is an explanatory diagram showing pulse patterns of dual-frequency RF power pulses in the first embodiment. [Figure 10] FIG. 3 is a cross-sectional view showing a pattern shape after etching in the first embodiment. [Figure 11] FIG. 10 is an explanatory diagram showing a pulse pattern of dual-frequency RF power pulses in a modified example of the first embodiment. [Figure 12] FIG. 10 is an explanatory diagram showing pulse patterns of dual-frequency RF power pulses in the second embodiment. [Figure 13] FIG. 10 is an explanatory diagram showing a pulse pattern of RF power pulses of two frequencies in one subcycle in the second embodiment. [Figure 14] FIG. 11 is an explanatory diagram showing pulse patterns of RF power pulses of three frequencies in the third embodiment. [Figure 15] FIG. 11 is an explanatory diagram showing a pulse pattern of RF power pulses of three frequencies in one subcycle in the third embodiment. [Figure 16] 10A and 10B are explanatory views showing how an etching target film is etched in the third embodiment. [Figure 17] FIG. 13 is an explanatory diagram showing pulse patterns of RF power pulses of three frequencies in the fourth embodiment. [Figure 18] FIG. 13 is an explanatory diagram showing a pulse pattern of RF power pulses of three frequencies in one subcycle in the fourth embodiment. [Figure 19] 10A and 10B are explanatory views showing how an etching target film is etched in the fourth embodiment. [Figure 20] FIG. 13 is an explanatory diagram showing a pulse pattern of RF power pulses of three frequencies in one period of the first sub-cycle in a modified example of the fourth embodiment. [Figure 21] FIG. 13 is an explanatory diagram showing a pulse pattern of RF power pulses of three frequencies in one period of the first sub-cycle in a modified example of the fourth embodiment. [Figure 22] FIG. 13 is an explanatory diagram showing a pulse pattern of RF power pulses of three frequencies in one period of the first sub-cycle in a modified example of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the manufacturing process of semiconductor devices, plasma processing such as etching and film formation is performed on semiconductor substrates (hereinafter referred to as "substrates") In plasma processing, plasma is generated by exciting a processing gas, and the substrate is processed by the plasma.

[0010] As one of the plasma sources, for example, an inductively coupled plasma (ICP) can be used. The plasma processing apparatus disclosed in the above-mentioned Patent Document 1 is an inductively coupled plasma processing apparatus, which supplies high frequency power for plasma excitation to an antenna to generate plasma from a processing gas, and supplies high frequency power for bias to a susceptor to attract ions to a substrate. Then, the substrate is subjected to plasma processing by the action of the generated plasma.

[0011] For example, when performing etching as a plasma process, it is important to control the incident angle of ions onto a film to be etched on a substrate to control the pattern shape after etching. In this regard, in the plasma processing method using the plasma processing system described in Patent Document 2, the source power includes multiple source power pulses, and the bias power includes multiple bias power pulses. Then, a pulse sequence is formed by combining these multiple source power pulses and multiple bias power pulses to generate plasma. Specifically, in this pulse sequence, source power pulses and bias power pulses are alternately combined so that they do not overlap in time, for example.

[0012] However, as a result of intensive research by the present inventors, it has been found that in plasma processing using the above-mentioned pulse sequence, the pattern shape after plasma processing, for example, etching, may not be the desired shape. In particular, when the pattern has sparse and dense patterns, there is room for improvement in controlling the shape.

[0013] The technology disclosed herein has been developed in consideration of the above circumstances, and uses multiple high-frequency power pulse signals to improve process performance and improve pattern shapes after plasma processing. Hereinafter, a plasma processing apparatus and a plasma processing method according to the present embodiment will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0014] <Plasma processing system> First, a plasma processing system according to one embodiment will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram that schematically shows the configuration of the plasma processing system.

[0015] In one embodiment, the plasma processing system includes a plasma processing device 1 and a controller 2. The plasma processing device 1 is configured to generate plasma from a processing gas in the plasma processing chamber 10 by supplying three high-frequency power pulses (three RF pulse signals) into the plasma processing chamber 10. The plasma processing device 1 may also be configured to generate plasma from a processing gas in the plasma processing chamber 10 by supplying two high-frequency power pulses (two RF pulse signals) into the plasma processing chamber 10. The plasma processing device 1 then processes a substrate by exposing the substrate to the generated plasma.

[0016] The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0017] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generating units may be used, including alternating current (AC) plasma generating units and direct current (DC) plasma generating units. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0018] The controller 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The controller 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the controller 2 may be included in the plasma processing apparatus 1. The controller 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on programs stored in the storage unit 2a2. The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0019] An example of the configuration of an inductively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described below with reference to Fig. 2. Fig. 2 is a vertical cross-sectional view showing an outline of the configuration of the plasma processing apparatus 1. In the plasma processing apparatus 1 of this embodiment, plasma processing is performed on a substrate (wafer) W, but the substrate W to be plasma processed is not limited to a wafer.

[0020] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. The plasma processing apparatus 1 also includes a substrate support 11, a gas inlet, and an antenna 14. The substrate support 11 is disposed within the plasma processing chamber 10. The antenna 14 is disposed on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, a sidewall 102 of the plasma processing chamber 10, and the substrate support 11.

[0021] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region (substrate support surface) 111a for supporting the substrate W and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. In one embodiment, the main body 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base can function as a lower electrode. The lower electrode may be disposed within the electrostatic chuck. The electrostatic chuck includes a ceramic plate and an electrostatic electrode disposed within the ceramic plate. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has a substrate support surface 111a. The ring assembly 112 includes one or more annular members, at least one of which is an edge ring. Although not shown, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate W to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0022] The gas inlet is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the gas inlet includes a center gas injector (CGI) 13. The center gas injector 13 is disposed above the substrate support 11 and attached to a central opening formed in the dielectric window 101. The center gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet port 13c. The process gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas inlet port 13c. Note that the gas inlet may include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 102 in addition to or instead of the center gas injector 13.

[0023] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the gas inlet through a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0024] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply three RF signals (RF power) to the conductive members of the substrate support 11 and the antenna 14. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the conductive members of the substrate support 11, a bias potential is generated on the substrate W, and ions in the formed plasma can be attracted to the substrate W.

[0025] In one embodiment, the RF power supply 31 includes a first RF generator 31 a, a second RF generator 31 b, and a third RF generator 31 c. The first RF generator 31 a is coupled to the antenna 14, and the second RF generator 31 b and the third RF generator 31 c are coupled to the conductive member.

[0026] The first RF generating unit 31a is coupled to the antenna 14 via at least one impedance matching circuit and is configured to generate a first RF pulse signal (a pulse signal of HF power) for plasma generation. The generated first RF pulse signal is supplied to the antenna 14. In one embodiment, the first RF pulse signal has a first frequency within a range of 13 MHz to 150 MHz. In one embodiment, the first RF pulse signal has a first frequency within a range of 13 MHz to 100 MHz. In one embodiment, the first RF pulse signal has a first frequency within a range of 20 MHz to 60 MHz. The first RF pulse signal includes a plurality of pulse cycles, specifically, a plurality of main cycles as described below. Each main cycle includes a first period and a second period. The first period includes a plurality of first subcycles, and the second period includes a plurality of second subcycles. The first subcycle has a first time period, and the second subcycle has a second time period. In one embodiment, the first time period is the same as the second time period. In this case, each main cycle includes a plurality of subcycles. The first RF pulse signal has at least three power levels, each of which is greater than or equal to zero. Thus, the first RF pulse signal may have high, middle, and low power levels, which are greater than zero. Alternatively, the first RF pulse signal may have high, low power levels and a zero power level (off). In one embodiment, the first RF pulse signal has three or more different power levels in each of the first sub-cycles and the second sub-cycles.

[0027] The second RF generating unit 31b is coupled to the lower electrode in the substrate support 11 via at least one impedance matching circuit and is configured to generate a second RF pulse signal (a pulse signal of LF1 power). The generated second RF pulse signal is supplied to the lower electrode in the substrate support 11. The second RF pulse signal has a second frequency. The second frequency may be the same as or different from the first frequency. In one embodiment, the second frequency is lower than the first frequency. In one embodiment, the second RF pulse signal has a second frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF pulse signal has a second frequency less than 1 MHz (kilohertz RF frequency). In one embodiment, the second RF pulse signal has a second frequency in the range of 1 MHz to 15 MHz. In one embodiment, the second RF pulse signal has a second frequency in the range of 100 kHz to 2 MHz. The second RF pulse signal includes a plurality of pulse cycles. The second RF pulse signal has at least two power levels, each of which is equal to or greater than zero. Therefore, the second RF pulse signal may have high and low power levels that are greater than zero. Alternatively, the second RF pulse signal may have a power level greater than zero and a zero power level, i.e., an on / off signal. In one embodiment, the second RF pulse signal has two or more different power levels in each of the plurality of first subcycles and has a zero power level in the second period.

[0028] The third RF generator 31c is coupled to the lower electrode in the substrate support 11 via at least one impedance matching circuit and is configured to generate a third RF pulse signal (a pulse signal of LF2 power). The generated third RF pulse signal is supplied to the lower electrode in the substrate support 11. In one embodiment, the third RF pulse signal has a lower frequency than the second RF pulse signal. In one embodiment, the third RF pulse signal has a third frequency in the range of 100 kHz to 4 MHz. In one embodiment, the third RF pulse signal has a third frequency in the range of 100 kHz to 2 MHz. In one embodiment, the third RF pulse signal has a third frequency less than 1 MHz (kilohertz RF frequency). The third RF pulse signal includes multiple pulse cycles. The third RF pulse signal has at least two power levels, each of which is equal to or greater than zero. Therefore, the third RF pulse signal may have high and low power levels, which are greater than zero. The third RF pulse signal may also have a power level greater than zero and a zero power level, i.e., an on / off signal. The third RF pulse signal has two or more different power levels in each of the plurality of first subcycles and has a zero power level in the second period.

[0029] In this manner, the first RF pulse signal, the second RF pulse signal, and the third RF pulse signal are pulsed. The second RF pulse signal and the third RF pulse signal are pulsed between an on state and an off state, or between two or more different on states (High / Low). The first RF pulse signal is pulsed between two or more different on states (High / Low) and an off state, or between three or more different on states (High / Middle / Low). The first RF pulse signal may also be pulsed between an on state and an off state, or between two different on states (High / Low).

[0030] The controller 2 outputs control signals to the first RF generator 31a, the second RF generator 31b, and the third RF generator 31c, instructing them to supply each pulse signal. As a result, the first RF pulse signal, the second RF pulse signal, and the third RF pulse signal, each including multiple pulse cycles (main cycle and sub-cycle), are supplied at predetermined timing, generating plasma from the processing gas in the plasma processing chamber 10. The generated plasma is then exposed to a substrate for plasma processing. This improves process efficacy and enables high-precision plasma processing. The timing at which the controller 2 controls the on / off states or power levels above zero of the first RF pulse signal, the second RF pulse signal, and the third RF pulse signal, will be described later.

[0031] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a bias DC generator 32a. In one embodiment, the bias DC generator 32a is connected to a conductive member of the substrate support 11 and configured to generate a bias DC signal. The generated bias DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the bias DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In various embodiments, the bias DC signal may be pulsed. Note that the bias DC generator 32a may be provided in addition to the RF power supply 31 or may be provided instead of the second RF generator 31b and the third RF generator 31c.

[0032] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the RF power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generator may be connected to both the outer coil and the inner coil, or separate RF generators may be connected to the outer coil and the inner coil separately.

[0033] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0034] <Pulse signal> Next, the pulse signals of the RF power will be described. For example, when the plasma processing is a process for etching a deep hole with a high aspect ratio, the pulse signals of the HF power, the LF1 power, and the LF2 power can be used to make the ion incident angle perpendicular or to increase the mask selectivity.

[0035] Figure 3 is an explanatory diagram showing an example of changes over time in radicals, ions, electron temperature (plasma electron temperature), ion energy, and by-products. The horizontal axis of Figure 3 represents the elapsed time (one cycle) after the supply of RF power is stopped (off). The vertical axis of Figure 3 represents the state of radicals, ions, electron temperature (Te), ion energy (εl), and by-products at each time during the off time.

[0036] As shown in Fig. 3, radicals change slowly after the RF power is turned off, whereas ion and electron temperatures change more quickly than radicals after the RF power is turned off. Taking into consideration the decay and energy changes of radicals, ions, and electron temperatures in the plasma, the pulse signals of the HF power and LF power (e.g., LF1 power and LF2 power) are controlled.

[0037] An example of a pulse signal of LF power to be supplied after turning off the HF power is to turn off the LF power during the initial period when the electron temperature is high, and then turn on the LF power after the electron temperature has dropped. In this case, ions remain in the plasma, but by using the LF power while the electron temperature is low, the ions can be efficiently attracted to the substrate.

[0038] Another example of the pulse signal of the LF power to be supplied after the HF power is turned off is to use the ion energy as a plasma parameter and control the LF2 power during a time when the electron temperature is almost unchanged. This allows the ion energy to be controlled and the ion incident angle to be controlled more vertically.

[0039] As described above, the timing of turning on / off the HF power and the LF power is controlled according to the behavior of plasma parameters such as radicals, ions, electron temperature, ion energy, and by-products. This improves the process performance. The supply timing of the RF power pulse signal will be described below. The supply timing of the RF power pulse signal is controlled by the control unit 2.

[0040] The following description will be given of a case where the plasma processing is an etching process and the film to be etched is, for example, silicon. However, the plasma processing to which the present disclosure is applied is not limited to etching processes and may be, for example, film formation processes. Furthermore, the film to be etched is not limited to silicon, and the present disclosure can also be applied to other film types.

[0041] <2-frequency pulse signal> The pulse patterns of the dual-frequency RF power pulses according to the first embodiment will be described using Comparative Examples 1 and 2. In the first embodiment, Comparative Examples 1 and 2, the dual-frequency (two) RF powers are HF power (source power) and LF1 power (bias power).

[0042] [Comparative Example 1] FIG. 4 is an explanatory diagram showing a pattern in which the two RF powers are continuous waves in Comparative Example 1. The horizontal axis of FIG. 4 represents time, and the vertical axis represents the on / off state of the HF power and the LF1 power. FIG. 5 shows the results when Comparative Example 1 is performed to etch a film to be etched. In FIG. 5, the left side of the dotted line represents an area (dense pattern Pa) where the pattern etched through the mask 201 on the film to be etched 200 is dense. The right side of the dotted line represents an area (sparse pattern Pb) where the pattern etched through the mask 201 on the film to be etched 200 is sparse.

[0043] In Comparative Example 1, as shown in FIG. 5, in the dense pattern Pa, few ions reach the bottoms of the recesses 200b between the protrusions 200a in the etching target film 200, resulting in excessive etching of the protrusions 200a. On the other hand, in the sparse pattern Pb, etching can be performed deeper than in the dense pattern Pa, but the protrusions 200a have a tapered shape that becomes thicker downward. Therefore, in Comparative Example 1, it may not be possible to appropriately control the shape of the sparse pattern after etching.

[0044] Comparative Example 2 Fig. 6 is an explanatory diagram showing the pulse pattern of dual-frequency RF power pulses in Comparative Example 2. Fig. 7 is an explanatory diagram showing the pulse pattern of dual-frequency RF power pulses for one subcycle in Comparative Example 2. The horizontal axis of Figs. 6 and 7 represents time, and the vertical axis represents the on / off state of the HF power and the LF1 power.

[0045] Each pulse signal of the HF power and the LF1 power includes a plurality of pulse cycles. Hereinafter, this pulse cycle will be referred to as a subcycle in accordance with the terminology of the first embodiment described below. A subcycle has a first subperiod (S1) and a second subperiod (S2), and control of each pulse signal of the HF power and the LF1 power is repeated with this subcycle as one period.

[0046] In the control of the dual-frequency RF power pulses in Comparative Example 2, the on state of the HF power and the on state of the LF1 power overlap in time. That is, while the HF power is on, the LF1 power is on, and while the HF power is off, the LF1 power is off.

[0047] The first RF generating unit 31a is configured to generate a first RF pulse signal (HF power), and the first RF pulse signal has two power levels (on / off) in Comparative Example 2. For example, the first RF pulse signal may have a frequency of 27 MHz.

[0048] The second RF generating unit 31b is configured to generate a second RF pulse signal (LF1 power), and in Comparative Example 2, the second RF pulse signal has two power levels (on / off). The frequency of the second RF pulse signal is lower than the frequency of the first RF pulse signal. For example, the second RF pulse signal has a frequency of 13 MHz.

[0049] 7, the HF power and the LF1 power are maintained in the ON state. That is, at time t0, the HF power and the LF1 power transition to the ON state, and at time t1, the HF power and the LF1 power transition to the OFF state. As a result, from time t0 to time t1, the supply of the HF power generates plasma containing radicals and ions, and the supply of the LF1 power controls the ion flux (amount of ions) that reaches the bottom of the recess to be etched, thereby accelerating etching.

[0050] At time t1 after the first sub-period (S1), the HF power and the LF1 power transition to the off state, and the HF power and the LF1 power are maintained in the off state during the second sub-period (S2). Since the HF power is in the off state during the second sub-period (S2), the radical, ion, and electron temperatures decay with their respective time constants, as shown in an example in Figure 3. Furthermore, since the HF power and the LF1 power are in the off state during the second sub-period (S2), by-products are exhausted.

[0051] At time t2 when the second sub-period (S2) has elapsed, the system returns from the second sub-period (S2) to the first sub-period (S1), and at time t0, the HF power and the LF1 power transition to the ON state again. Then, the control of the pulse signals of the HF power and the LF1 power is repeated, with the first sub-period (S1) and the second sub-period (S2) forming one cycle. One sub-cycle has a frequency of 1 kHz to 20 kHz. Multiple sub-cycles have the same time period, and each sub-cycle has a time period of 50 μs to 100 μs. In other words, one sub-cycle has a period of 50 μs to 100 μs.

[0052] In Comparative Example 2, the second RF generating section 31b is configured to synchronize the timing of the change in the power level of the second RF pulse signal with the timing of the change in the power level of the first RF pulse signal.

[0053] Furthermore, the first sub-period (S1) is set to 30 μs or less. The following second sub-period (S2) can be set to any length of time, even if it is longer than 30 μs. That is, in this example, the HF power and the LF1 power are maintained in an ON state for 30 μs or less in the first sub-period (S1), and are maintained in an OFF state for any length of time in the second sub-period (S2), repeating ON / OFF. In this way, by setting the supply time of the LF1 power in one cycle to 30 μs or less, ions can be controlled vertically, enabling highly anisotropic etching.

[0054] The power level of the HF power in the first sub-period (S1) is an example of a first power level. The power level of the HF power in the second sub-period (S2) is an example of a second power level, which is a zero power level. The power level of the LF1 power in the first sub-period (S1) is an example of a third power level. The power level of the LF1 power in the second sub-period (S2) is an example of a fourth power level, which is a zero power level.

[0055] In Comparative Example 2, as described above, the etching target film is etched using plasma in the first sub-period (S1), and by-products are exhausted in the second sub-period (S2). As a result, the pattern shape after etching can be improved compared to Comparative Example 1.

[0056] However, when the etching target film is etched by performing Comparative Example 1, in the dense pattern Pa, as shown in FIG. 8, the convex portions 200a are formed in the desired shape, but the etching target film 200 is not etched to the desired depth. On the other hand, in the sparse pattern Pb, although it can be etched deeper than the dense pattern Pa, the convex portions 200a have a tapered shape that becomes thicker downward. Therefore, in Comparative Example 2, the shape of the sparse pattern after etching may not be properly controlled. After extensive research, the inventors have found that the reason the pattern shape cannot be controlled in this way is because the second sub-period (S2) is short, and by-products are not sufficiently exhausted and remain in the concave portions 200b.

[0057] [First embodiment] Fig. 9 is an explanatory diagram showing the pulse pattern of dual-frequency RF power pulses in the first embodiment. The horizontal axis of Fig. 9 represents time, and the vertical axis represents the on / off state of the HF power and the LF1 power.

[0058] Each pulse signal of the HF power and the LF1 power includes a plurality of pulse cycles; specifically, each main cycle includes a plurality of main cycles as described below, and each main cycle includes a plurality of sub-cycles. The main cycle has a first period (M1) and a second period (M2). One period of the main cycle is 10 Hz to 200 Hz. The first period (M1) includes a plurality of first sub-cycles, and the second period (M2) includes a second sub-cycle. The periods of the first sub-cycles and the second sub-cycles are the same as the periods of the sub-cycles in Comparative Example 2, and one period of the first sub-cycles and the second sub-cycles is 1 kHz to 20 kHz. Control of each pulse signal of the HF power and the LF1 power is repeated, with one main cycle being one period.

[0059] 9, in each first sub-cycle, the pulse signals of the HF power and the LF1 power are controlled in the same manner as in the sub-cycle of Comparative Example 2. That is, in the first sub-cycle, the HF power and the LF1 power are maintained in an ON state in the first sub-period (S1), and the HF power and the LF1 power are maintained in an OFF state in the second sub-period (S2). Then, in the first sub-period (S1), the etching target film is etched using plasma containing radicals and ions, and by-products are exhausted in the second sub-period (S2). Then, in the first period (M1), this first sub-cycle is repeated, and etching of the etching target film progresses.

[0060] Next, in the second period (M2), in each second sub-cycle, the HF power pulse signal is controlled in the same manner as in the first period (M1). That is, in the first sub-period (S1), the HF power is maintained in an ON state, and in the second sub-period (S2), the HF power is maintained in an OFF state. Note that the HF power in the first sub-period (S1) is the same as the HF power that is turned ON in the first period (M1). On the other hand, in each second sub-cycle, the LF1 power is not supplied in both the first sub-period (S1) and the second sub-period (S2). That is, the power level of the LF1 power pulse signal (second RF pulse signal) is zero. In this case, since the LF1 power is OFF in the second period (M2), by-products are exhausted. Moreover, the second period (M2) is set to be sufficiently long so that by-products do not adhere to the substrate W.

[0061] When the etching target film is etched by carrying out the first embodiment, the convex portions 200a are formed in the desired shape in both the dense pattern Pa and the sparse pattern Pb, as shown in FIG. 10, and the etching target film 200 can be etched to the desired depth. This is because by turning off the LF1 power in the second period (M2), by-products are sufficiently exhausted and do not remain. In other words, by addressing the factors that improved the shape in Comparative Example 2, the first embodiment can appropriately control the shape of the sparse / dense pattern after etching.

[0062] Therefore, the first RF pulse signal (HF) has two or more different power levels (On / Off) in each of a plurality of first subcycles (Sub cycle 1) and a plurality of second subcycles (Sub cycle 2). The plurality of first subcycles are included in a first period (M1). The plurality of second subcycles are included in a second period (M2). The first subcycle has a first time period, and the second subcycle has a second time period. In one embodiment, the first time period is the same as the second time period. In this case, each main cycle includes a plurality of subcycles (Sub Cycle 1+Sub Cycle 2). The first RF pulse signal (HF) has a first pulse pattern in each of the plurality of first subcycles, and a second pulse pattern in each of the plurality of second subcycles. In one embodiment, the first pulse pattern is the same as the second pulse pattern. The second RF pulse signal (LF1) has two or more different power levels (On / Off) in each of a plurality of first subcycles within the first period (M1), and has a zero power level in the second period (M2). That is, the second RF pulse signal (LF1) is maintained at a zero power level in the second period (M2).

[0063] [Modification of the first embodiment] As a modification of the first embodiment, the HF power may be turned off without being supplied during the second period (M2) as shown in Fig. 11. In this case, etching of the etching target film does not progress during the second period (M2), and by-products are more reliably exhausted.

[0064] [Second embodiment] Fig. 12 is an explanatory diagram showing a pulse pattern of dual-frequency RF power pulses in the second embodiment. Fig. 13 is an explanatory diagram showing a pulse pattern of dual-frequency RF power pulses for one subcycle in the second embodiment. The horizontal axis of Fig. 12 and Fig. 13 represents time, and the vertical axis represents the on / off state of the HF power and the LF1 power.

[0065] As shown in FIG. 12, in the second embodiment, similar to the first embodiment, the main cycle has a first period (M1) including a plurality of first sub-cycles and a second period (M2) including a plurality of second sub-cycles. One period of the main cycle is 10 Hz to 200 Hz. As shown in FIG. 13, each sub-cycle of the HF power (first sub-cycle and second sub-cycle) includes a first sub-period (S1) and a second sub-period (S2), and one period consists of the first sub-period (S1), the second sub-period (S2), and the exhaust period. Each first sub-cycle of the LF1 power in the first period (M1) includes a third sub-period (S3) and a fourth sub-period (S4), and one period consists of the third sub-period (S3), the fourth sub-period (S4), and the exhaust period. During each second sub-cycle of the second period (M2), no LF1 power is supplied. One period of the first sub-cycle and the second sub-cycle is 1 kHz to 20 kHz. Then, with one main cycle as one period, control of the pulse signals of the HF power and the LF1 power is repeated.

[0066] The first RF generator 31a is configured to generate a first RF pulse signal (HF power), and in the second embodiment, the first RF pulse signal has two power levels (on / off). For example, the first RF pulse signal may have a frequency of 27 MHz.

[0067] The second RF generator 31b is configured to generate a second RF pulse signal (LF1 power), and in the second embodiment, the second RF pulse signal has two power levels (on / off). For example, the second RF pulse signal has a frequency of 13 MHz.

[0068] In the first period (M1), in each first sub-cycle, the on state of the HF power and the on state of the LF1 power do not overlap in time as shown in FIG. 13. For example, the first RF pulse signal has a first power level in the first sub-period (S1) and a second power level in the second sub-period (S2), with the first power level being in the on state and the second power level being in the off state. That is, the second power level is zero power level. The second RF pulse signal has a third power level in the third sub-period (S3) and a fourth power level in the fourth sub-period (S4), with the third power level being in the on state and the fourth power level being in the off state. That is, the fourth power level is zero power level. Note that the first power level may be high and the second power level may be low. Alternatively, the third power level may be high and the fourth power level may be low.

[0069] 13, the HF power is maintained in an ON state, and the LF1 power is maintained in an OFF state in a fourth sub-period (S4) that coincides with the first sub-period (S1) in time. As a result, plasma containing radicals and ions is generated by the supply of HF power from time t0 to time t1.

[0070] At time t1, the HF power transitions to the OFF state, the LF1 power transitions to the ON state, the HF power is maintained in the OFF state during the second sub-period (S2), and the LF1 power is maintained in the ON state during the third sub-period (S3) that coincides with the second sub-period (S2). Because the HF power is OFF during the second sub-period (S2), the radical, ion, and electron temperatures decay with their respective time constants, as shown in an example in Figure 3. By supplying the LF1 power during the third sub-period (S3), the ion flux (amount of ions) that reaches the bottom of the recess to be etched is controlled, thereby accelerating etching.

[0071] At time t2, the HF power is maintained in the off state, and the LF1 power transitions to the off state. In the exhaust period after the second sub-period (S2) and the third sub-period (S3), the HF power and the LF1 power are in the off state, so that by-products are exhausted.

[0072] One cycle ends at time t3, and transitions to the first sub-period (S1) of the next cycle. Then, at time t0 of the next cycle, the HF power transitions to the ON state again, and the LF1 power remains in the OFF state during the fourth sub-period (S4). That is, the first sub-cycle of the HF power is repeated, with the first sub-period (S1), second sub-period (S2), and exhaust period being one cycle. Also, the first sub-cycle of the LF1 power is repeated, with the fourth sub-period (S4), third sub-period (S3), and exhaust period being one cycle. One cycle of the first sub-cycle is 1 kHz to 20 kHz. The multiple first sub-cycles have the same time duration, and each first sub-cycle has a time duration of 50 μs to 1000 μs. That is, one cycle of the first sub-cycle is 50 μs to 1000 μs.

[0073] The third sub-period (S3) does not overlap in time with the first sub-period (S1). That is, the second RF generation unit 31b offsets the timing of the change in the power level of the second RF pulse signal from the timing of the change in the power level of the first RF pulse signal, so that the on state of the HF power and the on state of the LF1 power do not overlap in time.

[0074] In addition, the third sub-period (S3) is set to 30 μs or less. The first sub-period (S1), second sub-period (S2), and fourth sub-period (S4) can be set to any time period, even if they are longer than 30 μs. That is, in this example, the LF1 power is maintained in an ON state for 30 μs or less in the third sub-period (S3), and is maintained in an OFF state for any time period during the fourth sub-period (S4) and the exhaust period, repeating ON / OFF. In this way, by setting the supply time of the LF1 power in one cycle to 30 μs or less, ions can be controlled vertically, enabling highly anisotropic etching.

[0075] The power level of the HF power in the first sub-period (S1) is an example of a first power level, the power level of the HF power in the second sub-period (S2) is an example of a second power level, the power level of the LF1 power in the third sub-period (S3) is an example of a third power level, and the power level of the LF1 power in the fourth sub-period (S4) is an example of a fourth power level.

[0076] Next, in the second period (M2), in each second sub-cycle, the HF power pulse signal is controlled in the same manner as in the first period (M1). Meanwhile, in each second sub-cycle, the LF1 power is not supplied in both the third sub-period (S3) and the fourth sub-period (S4), i.e., the power level of the LF1 power pulse signal (second RF pulse signal) is zero. In this case, since the LF1 power is off in the second period (M2), by-products are exhausted. Moreover, the second period (M2) is set in advance to be sufficiently long so that by-products do not adhere to the substrate W.

[0077] <Three-frequency pulse signal> The pulse patterns of triple-frequency RF power pulses according to the third and fourth embodiments will be described. In the third and fourth embodiments, the triple-frequency RF powers are HF power (source power), LF1 power (bias power), and LF2 power (bias power). Each of the pulse signals of these multiple HF powers, LF1 power, and LF2 powers includes multiple pulse cycles, specifically multiple main cycles, and each main cycle includes multiple sub-cycles.

[0078] [Third embodiment] Fig. 14 is an explanatory diagram showing a pulse pattern of triple-frequency RF power pulses in the third embodiment. Fig. 15 is an explanatory diagram showing a pulse pattern of triple-frequency RF power pulses for one subcycle in the third embodiment. The horizontal axis of Figs. 14 and 15 represents time, and the vertical axis represents the on / off state of the HF power and the LF1 power.

[0079] As shown in FIG. 14, in the third embodiment, similarly to the first and second embodiments, the main cycle has a first period (M1) including a plurality of first sub-cycles and a second period (M2) including a plurality of second sub-cycles. One period of the main cycle is 10 Hz to 200 Hz. As shown in FIG. 15, each first sub-cycle of the first period (M1) has a first sub-period (S1) to a third sub-period (S3) as one period. LF1 power is not supplied. One period of the first sub-cycle is 1 kHz to 20 kHz. Control of the pulse signals of the HF power, LF1 power, and LF2 power is repeated, with the main cycle being one period.

[0080] The first RF generator 31a is configured to generate a first RF pulse signal (HF power). In the third embodiment, the first RF pulse signal has three power levels (High / Low / Off). These power levels can be arbitrarily set and changed depending on the target process. For example, the first RF pulse signal may have a frequency of 27 MHz.

[0081] The second RF generating unit 31b is configured to generate a second RF pulse signal (LF1 power), and in the third embodiment, the second RF pulse signal has two power levels (on / off). That is, the second RF pulse signal has two or more power levels including a zero power level. The frequency of the second RF pulse signal is lower than the frequency of the first RF pulse signal. For example, the second RF pulse signal has a frequency of 13 MHz.

[0082] The third RF generating unit 31c is configured to generate a third RF pulse signal (LF2 power), and in the third embodiment, the third RF pulse signal has two power levels (on / off). That is, the third RF pulse signal has two or more power levels including a zero power level. The frequency of the third RF pulse signal is lower than the frequency of the second RF pulse signal. For example, the third RF pulse signal has a frequency of 1.2 MHz.

[0083] In the first period (M1), in each first subcycle, the on state of the LF1 power and the on state of the LF2 power do not overlap in time, and while the LF1 power is on, the LF2 power is off, and while the LF1 power is off, the LF2 power is on. The on states of the HF power and the LF1 power, and the on states of the HF power and the LF2 power, may overlap in time, or may not overlap.

[0084] For example, the first RF pulse signal has a first power level in the first sub-period (S1), a second power level in the second sub-period (S2), and a third power level in the third sub-period (S3), with the first and second power levels being in an on state and the third power level being in an off state. The first power level is greater than the second power level. The third power level is a zero power level. The second RF pulse signal has a fourth power level in the first sub-period (S1) and a fifth power level in the second sub-period (S2) and the third sub-period (S3), with the fourth power level being in an on state and the fifth power level being in an off state. That is, the fifth power level is a zero power level. The third RF pulse signal has a sixth power level in the second sub-period (S2) and a seventh power level in the first sub-period (S1) and the third sub-period (S3), with the sixth power level being in an on state and the seventh power level being in an off state. That is, the seventh power level is a zero power level.

[0085] Therefore, the first RF pulse signal (HF) has three or more different power levels (High / Low / Off) in each of a plurality of first subcycles (Sub cycle 1) and a plurality of second subcycles (Sub cycle 2). The plurality of first subcycles are included in a first period (M1). The plurality of second subcycles are included in a second period (M2). The first subcycle has a first time period, and the second subcycle has a second time period. In one embodiment, the first time period is the same as the second time period. In this case, each main cycle includes a plurality of subcycles (Sub Cycle 1+Sub Cycle 2). The first RF pulse signal (HF) has a first pulse pattern in each of the plurality of first subcycles, and a second pulse pattern in each of the plurality of second subcycles. In one embodiment, the first pulse pattern is the same as the second pulse pattern. Furthermore, the second RF pulse signal (LF1) has two or more different power levels (On / Off) in each of a plurality of first subcycles within the first period (M1), and has a zero power level in the second period (M2). That is, the second RF pulse signal (LF1) is maintained at a zero power level in the second period (M2). Furthermore, the third RF pulse signal (LF2) has two or more different power levels (On / Off) in each of a plurality of first subcycles within the first period (M1), and has a zero power level in the second period (M2). That is, the third RF pulse signal (LF2) is maintained at a zero power level in the second period (M2).

[0086] In one embodiment, the plasma processing method includes the following steps in each first subcycle within the first period (M1): periodically supplying a first RF pulse signal (HF) having three or more different power levels (High / Low / Off) to the antenna 14; periodically supplying a second RF pulse signal (LF1) having two or more different power levels (On / Off) to the lower electrode within the substrate support 11; and periodically supplying a third RF pulse signal (LF2) having two or more different power levels (On / Off) to the lower electrode within the substrate support 11. The plasma processing method also includes the following steps in the second period (M2): periodically supplying the first RF pulse signal (HF) to the antenna 14 without supplying the second RF pulse signal (LF1) and the third RF pulse signal (LF2) to the lower electrode within the substrate support 11.

[0087] In the first sub-period (S1) of FIG. 15, the HF power has a high power level, the LF1 power is on, and the LF2 power is off. That is, from time t0 to time t11, plasma containing radicals and ions is generated by supplying the HF power. Furthermore, from time t0 to time t11, the LF1 power is supplied, which controls the ion flux (amount of ions) that reaches the bottom of the recess to be etched, thereby accelerating etching. As a result, as shown in FIG. 16(a), the etching target film 200 is etched through the mask 201, and mainly radicals R adhere to the inner wall of the recess 200b formed in the etching target film 200. Furthermore, the ions are controlled to control the ion flux that reaches the bottom of the etched recess 200b.

[0088] Furthermore, the first sub-period (S1) is set to a time of 30 μs or less. The subsequent second sub-period (S2) and third sub-period (S3) can be set to any time, even if they are longer than 30 μs. That is, in this example, the HF power and LF1 power are maintained in an on state for a time of 30 μs or less in the first sub-period (S1). In this way, by supplying the LF1 power for a short time of 30 μs or less in the first sub-period (S1), the ions can be further controlled vertically, enabling highly anisotropic etching.

[0089] After the first sub-period (S1) has elapsed, at time t11, the HF power transitions from a high power level to a low power level (or an OFF state), the LF1 power transitions to an OFF state, and the LF2 power transitions to an ON state. As a result, the radical, ion, and electron temperatures decay with their respective time constants, as shown in an example in Figure 3. Depending on the decay state of these plasma parameters, the power level of the HF power is reduced or the timing for turning on the LF2 power is controlled during the second sub-period (S2) in which it is controlled to an OFF state, and during the third sub-period (S3) in which by-products are exhausted.

[0090] In the second sub-period (S2), the HF power is maintained at a low power level, the LF1 power is maintained in an off state, and the LF2 power is maintained in an on state. In the second sub-period (S2), LF2 power is supplied at a frequency lower than the frequency of the LF1 power supplied in the first sub-period (S1). The Vpp of the LF2 power is greater than the Vpp of the LF1 power. This allows the bias voltage Vpp to be greater in the second sub-period (S2) than in the first sub-period (S1), increasing the ion energy and controlling the ion incident angle to be more perpendicular. This allows the ion flux reaching the bottom of the recess 200b etched in the second sub-period (S2) to be controlled, as shown in FIG. 16(b). This also allows by-products B and other substances remaining in the corners of the bottom of the recess 200b to be etched, accelerating the etching process.

[0091] At time t12, the HF power transitions to the OFF state (or low power level), the LF1 power remains OFF, and the LF2 power transitions to the OFF state. In the third sub-period (S3), exhaust of by-product B is controlled. That is, in the third sub-period (S3), the HF power, the LF1 power, and the LF2 power are maintained OFF. This allows exhaust of by-product B adhering to the recess 200b. This facilitates etching in the next cycle.

[0092] At time t13, the first sub-period (S1) is resumed, the HF power transitions to a high power level, the LF1 power transitions to an ON state, and the LF2 power is maintained in an OFF state. The first sub-period (S1) to the third sub-period (S3) are repeated, with one cycle of the first sub-cycle ranging from 1 kHz to 20 kHz. The multiple first sub-cycles have the same time period, with each first sub-cycle ranging from 50 μs to 100 μs. That is, one cycle of the first sub-cycle ranges from 50 μs to 100 μs.

[0093] In this way, in the first period (M1), in the process of etching a deep hole with a high aspect ratio, the mask selectivity can be increased and the ion incident angle can be made vertical by using the pulse signals of the HF power, LF1 power, and LF2 power, thereby making it possible to make the etching profile vertical and accelerating etching.

[0094] Next, in the second period (M2), in each second sub-cycle, the HF power pulse signal is controlled in the same manner as in the first period (M1). Meanwhile, in each second sub-cycle, in any of the first sub-period (S1) to third sub-period (S3), the LF1 power and the LF2 power are not supplied. That is, the power levels of the LF1 power pulse signal (second RF pulse signal) and the LF2 power pulse signal (third RF pulse signal) are zero. In this case, in the second period (M2), the LF1 power and the LF2 power are in an off state, so by-products are exhausted. Moreover, the second period (M2) is set in advance to be sufficiently long so that by-products do not adhere to the substrate W.

[0095] In the third embodiment, the power level of the HF power is controlled to three levels, and the power levels of the LF1 power and the LF2 power are controlled to two levels, on and off, but this is not limiting. For example, the power level of the HF power may be controlled to four or more levels.

[0096] [Fourth embodiment] Fig. 17 is an explanatory diagram showing a pulse pattern of triple-frequency RF power pulses in the fourth embodiment. Fig. 18 is an explanatory diagram showing a pulse pattern of triple-frequency RF power pulses for one subcycle in the fourth embodiment. The horizontal axes of Figs. 17 and 18 represent time, and the vertical axes represent the on / off states of the HF power and the LF1 power.

[0097] As shown in FIG. 17, in the fourth embodiment, similar to the third embodiment, the main cycle has a first period (M1) including a plurality of first subcycles and a second period (M2) including a plurality of second subcycles. One period of the main cycle is 10 Hz to 200 Hz. As shown in FIG. 15, each subcycle (first subcycle and second subcycle) of the HF power includes a first subperiod (S1) to a third subperiod (S3). Each first subcycle of the LF1 power in the first period (M1) includes a fourth subperiod (S4) and a fifth subperiod (S5). Each first subcycle of the LF2 power in the first period (M1) includes a sixth subperiod (S6) and a seventh subperiod (S7). In each second subcycle of the second period (M2), the LF1 power and the LF2 power are not supplied. One period of the first and second subcycles is 1 kHz to 20 kHz. Then, with one main cycle as one period, control of the pulse signals of the HF power, LF1 power, and LF2 power is repeated.

[0098] The first RF generator 31a is configured to generate a first RF pulse signal (HF power), and in the fourth embodiment, the first RF pulse signal has three power levels (High / Low / Off). These power levels can be arbitrarily set and changed depending on the target process. For example, the first RF pulse signal may have a frequency of 27 MHz.

[0099] The second RF generating unit 31b is configured to generate a second RF pulse signal (LF1 power), and in the fourth embodiment, the second RF pulse signal has two power levels (on / off). That is, the second RF pulse signal has two or more power levels including a zero power level. The frequency of the second RF pulse signal is lower than the frequency of the first RF pulse signal. For example, the second RF pulse signal has a frequency of 13 MHz.

[0100] The third RF generating unit 31c is configured to generate a third RF pulse signal (LF2 power), and in the fourth embodiment, the third RF pulse signal has two power levels (on / off). That is, the third RF pulse signal has two or more power levels including a zero power level. The frequency of the third RF pulse signal is lower than the frequency of the second RF pulse signal. For example, the third RF pulse signal has a frequency of 1.2 MHz.

[0101] 18, in each first subcycle, the on state of the LF1 power and the on state of the LF2 power do not overlap in time, and while the LF1 power is on, the LF2 power is off, and while the LF1 power is off, the LF2 power is on. Also, the high power level of the HF power and the on state of the LF1 power do not overlap in time, and while the HF power is at the high power level, the LF1 power is off, and while the LF1 power is on, the HF power is off or at a low power level. Similarly, the high power level of the HF power and the on state of the LF2 power do not overlap in time, and while the HF power is at the high power level, the LF2 power is off, and while the LF2 power is on, the HF power is off or at a low power level.

[0102] For example, the first RF pulse signal has a first power level in the first sub-period (S1), a second power level in the second sub-period (S2), and a third power level in the third sub-period (S3), with the first and second power levels being in an on state and the third power level being in an off state. The first power level is greater than the second power level. The second power level is greater than the third power level, and the third power level is a zero power level. The second RF pulse signal has a fourth power level in the fourth sub-period (S4) and a fifth power level in the fifth sub-period (S5), with the fourth power level being in an on state and the fifth power level being in an off state. That is, the fifth power level is a zero power level. The third RF pulse signal has a sixth power level in the sixth sub-period (S6) and a seventh power level in the seventh sub-period (S7), with the sixth power level being in an on state and the seventh power level being in an off state. That is, the seventh power level is a zero power level.

[0103] In the first sub-period (S1) of Fig. 18, the HF power is at a high power level, and the LF1 power and the LF2 power are in an off state. That is, from time t0 to time t11, plasma containing radicals and ions is generated by supplying the HF power. As a result, as shown in Fig. 19(a), the etching target film 200 is etched through the mask 201, and mainly radicals R adhere to the inner walls of the recesses 200b formed in the etching target film 200.

[0104] When the HF power transitions to the OFF state at time t11 after the first sub-period (S1) has elapsed, the radical, ion, and electron temperatures decay with their respective time constants, as shown in an example in FIG. 3. The timings for turning on the LF1 and LF2 powers during the third sub-period (S3), in which the HF power is turned OFF, the second sub-period (S2), in which the power level is reduced, and the period in which by-products are exhausted are controlled according to the decay states of these plasma parameters. The fourth sub-period (S4), in which the LF1 power is turned ON, does not overlap in time with the first sub-period (S1), in which the HF power is set to a high power level. Furthermore, the sixth sub-period (S6), in which the LF2 power is turned ON, does not overlap in time with the first sub-period (S1) and the fourth sub-period (S4).

[0105] At time t11, the HF power transitions from the high power level to the OFF state, and the LF1 power transitions to the ON state. As a result, during the fourth sub-period (S4) that coincides with the third sub-period (S3), the LF1 power is maintained in the ON state, which controls the ion flux that reaches the bottom of the etched recess 200b, as shown in FIG. 19(b). This also reduces the amount of by-products produced during etching. The LF2 power remains in the OFF state at time t11, and during the seventh sub-period (S7) that coincides with the third sub-period (S3), the LF2 power is maintained in the OFF state.

[0106] Furthermore, the fourth sub-period (S4) is set to a time of 30 μs or less. Moreover, the fourth sub-period (S4) does not overlap in time with the first sub-period (S1). By supplying LF1 power for a short time of 30 μs or less in the fourth sub-period (S4), it is possible to further control the ions vertically and achieve highly anisotropic etching.

[0107] At time t12 after the third sub-period (S3) and the fourth sub-period (S4) have elapsed, the HF power transitions to a low power level, the LF1 power transitions to an off state, and the LF2 power transitions to an on state. In the second sub-period (S2) until time t13, the HF power remains at a low power level. In the third sub-period (S3) and the second sub-period (S2), the HF power may be at a low power level or in an off state. In the fifth sub-period (S5), which coincides with the second sub-period (S2), the LF1 power remains in an off state, and in the sixth sub-period (S6), which coincides with the second sub-period (S2), the LF2 power remains in an on state. As described above, the sixth sub-period (S6) does not overlap with the first sub-period (S1) and the fourth sub-period (S4).

[0108] In the sixth sub-period (S6), LF2 power is supplied at a frequency lower than the frequency of the LF1 power supplied in the fourth sub-period (S4). The Vpp of the LF2 power is greater than the Vpp of the LF1 power. This allows the bias voltage Vpp to be greater in the sixth sub-period (S6) than in the fourth sub-period (S4), thereby increasing the ion energy and controlling the ion incident angle to be more perpendicular. This allows the ion flux reaching the bottom of the recess 200b etched in the sixth sub-period (S6) while the LF2 power is being supplied to be controlled, as shown in FIG. 19(c). This also allows by-products B and other substances remaining in the corners of the bottom of the recess 200b to be etched, accelerating the etching process.

[0109] At time t14, one cycle ends and transitions to the first sub-period (S1) of the next cycle. Then, at time t0 of the next cycle, the HF power transitions to a high power level, while the LF1 power and LF2 power remain off. The first RF pulse signal sets the HF power to a predetermined state in the order of the first sub-period (S1), the third sub-period (S3), the second sub-period (S2), and the exhaust period. The second RF pulse signal sets the LF1 power to a predetermined state in the order of the fourth sub-period (S4), the fifth sub-period (S5), and the exhaust period. The third RF pulse signal sets the LF2 power to a predetermined state in the order of the seventh sub-period (S7), the sixth sub-period (S6), and the exhaust period. Each first sub-cycle is repeated, and one cycle is between 1 kHz and 20 kHz. Multiple first sub-cycles have the same time duration, and each first sub-cycle has a time duration of 50 μs to 1000 μs. That is, one period of the first sub-cycle is 50 μs to 1000 μs.

[0110] In this way, in the first period (M1), in the process of etching a deep hole with a high aspect ratio, the mask selectivity can be increased and the ion incident angle can be made vertical by using the pulse signals of the HF power, LF1 power, and LF2 power, thereby making it possible to make the etching profile vertical and accelerating etching.

[0111] Next, in the second period (M2), in each second sub-cycle, the HF power pulse signal is controlled in the same manner as in the first period (M1). Meanwhile, in each second sub-cycle, the LF1 power and the LF2 power are not supplied. That is, the power levels of the LF1 power pulse signal (second RF pulse signal) and the LF2 power pulse signal (third RF pulse signal) are zero power levels. In this case, since the LF1 power and the LF2 power are in an off state in the second period (M2), by-products are exhausted. Moreover, the second period (M2) is set in advance to be sufficiently long so that by-products do not adhere to the substrate W.

[0112] In the fourth embodiment, the power level of the HF power is controlled to three levels, and the power levels of the LF1 power and the LF2 power are controlled to two levels, on and off, but this is not limiting. For example, the power level of the HF power may be controlled to four or more levels.

[0113] [Modification of the fourth embodiment] Next, a modified example of the fourth embodiment will be described. In this modified example, the pulse pattern of the triple-frequency RF power pulses in each first sub-cycle of the first period (M1) is changed in the fourth embodiment. Figures 20 to 22 are explanatory diagrams showing the pulse pattern of the dual-frequency RF power pulses in one period of the first sub-cycle in the modified example of the fourth embodiment.

[0114] A modification shown in FIG. 20 will be described.

[0115] The difference between the pulse pattern shown in Fig. 18 and the pulse pattern shown in Fig. 20 is that there is a delay time Tdelay after the end time t11 of the first sub-period (S1) in Fig. 20, but there is no delay time Tdelay after time t11 in Fig. 18. This difference will be explained below, and the other pulse patterns in Fig. 20 are the same as those in Fig. 18, so explanations will be omitted.

[0116] For example, as shown in FIG. 3, if the LF1 power or the LF2 power is turned on when the electron temperature is high, a large amount of by-products may be generated, which may hinder etching. For this reason, it is conceivable to turn on the LF1 power or the LF2 power when the electron temperature is not high. That is, at time t21, after a predetermined delay time Tdelay has elapsed since time t11, the electron temperature has dropped. At this timing, the LF1 power transitions to the on state. That is, the LF1 power transitions to the on state after a shift (delay) of the delay time Tdelay from time t11, when the HF power transitions to the off state. This makes it possible to suppress the amount of by-products generated during etching and promote etching.

[0117] In this modification, the HF power is turned off during the delay time Tdelay. However, the power level of the HF power during the delay time Tdelay may be set to a low level lower than the power level of the HF power during the first sub-period (S1). Lowering the power level of the HF power reduces the generation of radicals and ions during the delay time Tdelay, which occurs before the timing of supplying the LF1 power at time t21. As a result, the ion flux reaching the bottom of the recess formed in the film to be etched during the fourth sub-period (S4), from time t21 to time t12 after the delay time Tdelay has elapsed, can be controlled. The fourth sub-period (S4) is set to a time of 30 μs or less. Furthermore, the fourth sub-period (S4) does not overlap with the first sub-period (S1). The subsequent fifth sub-period (S5) and exhaust period can be set to any time and may be longer than 30 μs. In this way, by supplying the LF1 power for a short time of 30 μs or less in the fourth sub-period (S4), the ions can be controlled further vertically, enabling highly anisotropic etching.

[0118] At time t12, the LF1 power transitions to the OFF state, and the LF2 power transitions to the ON state. In the fifth sub-period (S5), the LF1 power transitions to the OFF state, and in the sixth sub-period (S6), which overlaps with the fifth sub-period (S5), the LF2 power transitions to the ON state. This allows the ion incident angle to be controlled more perpendicularly in the sixth sub-period (S6) compared to the fourth sub-period (S4). However, if the delay time Tdelay is made too long, ions will disappear, so the delay time Tdelay is set to an appropriate value in advance.

[0119] This control primarily controls ion behavior by transitioning the LF1 power on / off state and the LF2 power on / off state to the on state at different time periods. The HF power has a zero power level in the third subperiod (S3), the LF1 power has a power level greater than zero in the fourth subperiod (S4), and the LF2 power has a zero power level in the seventh subperiod (S7) that overlaps with the fourth subperiod (S4). The LF2 power has a power level greater than zero in the sixth subperiod (S6), the LF1 power has a zero power level in the fifth subperiod (S5) that overlaps with the sixth subperiod (S6), and the HF power has a power level greater than zero in the second subperiod (S2). That is, the LF1 power and the LF2 power do not overlap during times when they have power levels greater than zero.

[0120] LF2 power has a higher mask selectivity than LF1 power, enabling vertical etching. In the first sub-period (S1), where the power level of the HF power is higher than in the second sub-period (S2), a large amount of radicals and ions are generated, and supplying LF2 power during the first sub-period (S1) is unlikely to produce the above-mentioned effect. On the other hand, in the second sub-period (S2), where the power level of the HF power is lower than in the first sub-period (S1), and in the third sub-period (S3), where the power level is zero, the generation of radicals and ions is reduced. Therefore, the above-mentioned effect is more easily achieved by supplying LF1 power during the fourth sub-period (S4) overlapping with the third sub-period (S3) and LF2 power during the sixth sub-period (S6) overlapping with the second sub-period (S2). Therefore, supplying LF1 power or LF2 power during these periods increases ion energy and makes the ion incident angle perpendicular. As a result, in the second sub-period (S2) and the third sub-period (S3), the mask selectivity is higher than in the first sub-period (S1), and vertical etching becomes possible.

[0121] The LF1 power and the LF2 power can generate pulse signals having two power levels, an on state and an off state. However, pulse signals having two or more power levels may be generated, such as an on state, an off state, and an intermediate power level for the LF1 power and the LF2 power. The LF1 power and the LF2 power may have two different on states.

[0122] A modification shown in FIG. 21 will be described.

[0123] The difference between the pulse pattern in Fig. 21 and the pulse pattern in Fig. 20 is that the order of the ON state of the LF1 power and the ON state of the LF2 power is reversed, and the timing of the delay time Tdelay is shifted accordingly. The delay time Tdelay is provided just before the LF1 power transitions to the ON state.

[0124] In this modification, too, the LF1 power or the LF2 power is turned on to avoid times when the electron temperature is high. In this modification, the LF2 power is turned on first, followed by the LF1 power. The electron temperature has dropped at time t11 after the first sub-period (S1) has elapsed. At this timing, i.e., at time t11 when the HF power transitions to a low power level lower than the high power level, the LF2 power transitions to the on state, and the LF2 power is maintained in the on state during the sixth sub-period (S6), which coincides with the second sub-period (S2). This makes it possible to suppress the amount of by-products produced during etching and promote etching.

[0125] During the fifth subperiod (S5), which coincides with the second subperiod (S2) from time t11 to time t12, the LF1 power remains in the off state. In this variation, at time t12, the HF power transitions to the off state, the LF1 power remains in the off state, and the LF2 power transitions to the off state. The HF power is maintained in the off state during the delay time Tdelay; however, the power level of the HF power during the delay time Tdelay may be a low level lower than the power level of the HF power during the first subperiod (S1). Further reducing the power level of the HF power can reduce the generation of radicals and ions during the delay time Tdelay, which is before time t22 when the LF1 power is supplied.

[0126] At time t22, after the delay time Tdelay has elapsed since time t12, the LF1 power transitions to the ON state. At time t22, the HF power and the LF2 power remain OFF. As a result, the ion flux reaching the bottom of the recess formed in the film to be etched can be controlled during the fourth sub-period (S4), which is from time t22 to time t13 after the delay time Tdelay has elapsed. The fourth sub-period (S4) is set to a time of 30 μs or less. The fourth sub-period (S4) does not overlap with the first sub-period (S1). The fifth sub-period (S5), which coincides with the second sub-period (S2) in time, and the exhaust period can be set to any time and may be longer than 30 μs. In other words, in this modification, the LF1 power remains ON for a time of 30 μs or less during the fourth sub-period (S4). In this way, by supplying LF1 power for a short time of 30 μs or less in the fourth sub-period (S4), the ions can be controlled more vertically, enabling highly anisotropic etching. However, since the ions disappear if the delay time Tdelay is made too long, the delay time Tdelay is set to an appropriate value in advance.

[0127] A modification shown in FIG. 22 will be described.

[0128] The difference between the pulse pattern in Figure 22 and the pulse patterns in Figures 20 and 21 is that the delay time Tdelay is set just before the LF1 power transitions to the ON state in Figures 20 and 21, but is set just before the LF2 power transitions to the ON state in Figure 22.

[0129] In this modification, in the first sub-period (S1), the HF power is maintained at a high power level, and the LF1 power and the LF2 power are maintained in an off state. In the third sub-period (S3), and in the fifth sub-period (S5) and seventh sub-period (S7) which coincide in time with the third sub-period (S3), the HF power, the LF1 power, and the LF2 power are all maintained in an off state (exhaust period).

[0130] Then, at time t21, the HF power transitions to a low power level lower than the high power level, and the LF1 power transitions to the on state. At time t21, the LF2 power remains in the off state. Then, in the second sub-period (S2), the HF power is maintained at the low power level. This overlaps with the second sub-period (S2) in time. That is, in the fourth sub-period (S4), which coincides in time with a portion of the second sub-period (S2), the LF1 power remains in the on state for 30 μs or less. At time t22 during the second sub-period (S2), the LF1 power transitions to the off state, and at time t23, after the delay time Tdelay has elapsed from time t22, the LF2 power transitions to the on state. At times t22 and t23, the HF power is maintained at the low power level. Then, from time t23 onwards, the LF2 power is maintained in the ON state during a sixth sub-period (S6) which overlaps in time with the second sub-period (S2) (that is, which coincides in time with a part of the second sub-period (S2)).

[0131] In this modified example, during the second sub-period (S2) in which the HF power is maintained at the low power level, the LF1 power and the LF2 power are alternately turned on. Furthermore, during the fourth sub-period (S4), the LF1 power is supplied for a short period of 30 μs or less. This further controls the ions vertically, enabling highly anisotropic etching. The control of the exhaust period from time t24 to time t25 after the sixth sub-period (S6) has elapsed is the same as that of the other first sub-cycles, and therefore will not be described here.

[0132] As described above, according to the plasma processing apparatus and plasma processing method of this embodiment, it is possible to improve the process performance by using a plurality of RF power pulse signals.

[0133] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0134] For example, although the above embodiment has been described using an inductively coupled plasma device as an example, the present invention is not limited thereto and may be applied to other plasma devices. For example, a capacitively coupled plasma device may be used instead of the inductively coupled plasma device. In this case, the capacitively coupled plasma device includes an upper electrode and a lower electrode. The lower electrode is disposed within a substrate support, and the upper electrode is disposed above the substrate support. The first RF generator 31a is coupled to the upper electrode or the lower electrode, and the second RF generator 31b and the third RF generator 31c are coupled to the lower electrode. Therefore, the first RF generator 31a is coupled to the antenna 14 of the inductively coupled plasma device or the upper electrode of the capacitively coupled plasma device. That is, the first RF generator 31a is coupled to the plasma processing chamber. [Explanation of symbols]

[0135] 1. Plasma processing equipment 10 Plasma Processing Chamber 31a 1st RF generation section 31b Second RF Generation Section 31c Third RF Generation Unit

Claims

1. a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an electrode disposed within the substrate support; a first RF generator coupled to the plasma processing chamber and configured to generate a first RF pulse signal including a plurality of main cycles, each main cycle including a first period and a second period, the first period including a plurality of first sub-cycles, and the second period including a plurality of second sub-cycles, the first RF pulse signal having three or more different power levels in each of the plurality of first sub-cycles and the plurality of second sub-cycles; a second RF generator coupled to the electrode and configured to generate a second RF pulse signal comprising the plurality of main cycles, the second RF pulse signal having two or more different power levels in each of the plurality of first sub-cycles and a zero power level in the second period; a third RF generator coupled to the electrode and configured to generate a third RF pulse signal comprising the plurality of main cycles, the third RF pulse signal having two or more different power levels in each of the plurality of first sub-cycles and a zero power level in the second period; A plasma processing apparatus comprising:

2. the first RF pulse signal has a first frequency; the second RF pulse signal has a second frequency lower than the first frequency; The plasma processing apparatus of claim 1 , wherein the third RF pulse signal has a third frequency lower than the second frequency.

3. the first RF pulse signal has a first power level, a second power level, and a third power level; the second RF pulse signal has a fourth power level and a fifth power level; the third RF pulse signal has a sixth power level and a seventh power level; a duration of the fourth power level coincides with a duration of the first power level; 3. The plasma processing apparatus of claim 1, wherein a period of the sixth power level coincides with a period of the second power level.

4. a duration of the fifth power level coincides with a duration of the second power level; 4. The plasma processing apparatus of claim 3, wherein a duration of the seventh power level coincides with a duration of the first power level.

5. The plasma processing apparatus of claim 3 , wherein the third power level, the fifth power level, and the seventh power level are a zero power level.

6. The plasma processing apparatus of claim 3 , wherein the first power level is greater than the second power level.

7. 4. The plasma processing apparatus of claim 3, wherein the duration of the first power level is 30 .mu.s or less.

8. the first RF pulse signal has a first power level, a second power level, and a third power level; the second RF pulse signal has a fourth power level and a fifth power level; the third RF pulse signal has a sixth power level and a seventh power level; a period of the fourth power level does not overlap with a period of the first power level; a period of the sixth power level does not overlap with a period of the first power level; 3. The plasma processing apparatus of claim 1, wherein the period of the sixth power level does not overlap with the period of the fourth power level.

9. The plasma processing apparatus of claim 8 , wherein the third power level, the fifth power level, and the seventh power level are a zero power level.

10. the first power level is greater than the second power level; the second power level is greater than the third power level; a period of the fourth power level overlaps with a period of the third power level; The plasma processing apparatus of claim 8 , wherein the period of the sixth power level overlaps with the period of the second power level.

11. the third power level transitions from the first power level, and the second power level transitions from the third power level; a duration of the fourth power level coincides with a duration of the third power level; The plasma processing apparatus of claim 10 , wherein a duration of the sixth power level coincides with a duration of the second power level.

12. the third power level transitions from the first power level, and the second power level transitions from the third power level; the fourth power level starts a predetermined time after the transition from the first power level to the third power level and ends simultaneously with the transition from the third power level to the second power level; The plasma processing apparatus of claim 10 , wherein a duration of the sixth power level coincides with a duration of the second power level.

13. the second power level transitions from the first power level, and the third power level transitions from the second power level; the fourth power level starts a predetermined time after the transition from the second power level to the third power level and ends simultaneously with the end of the third power level; The plasma processing apparatus of claim 10 , wherein a duration of the sixth power level coincides with a duration of the second power level.

14. the first power level is greater than the second power level; the second power level is greater than the third power level; a period of the fourth power level overlaps with a period of the second power level; The plasma processing apparatus of claim 8 , wherein the period of the sixth power level overlaps with the period of the second power level.

15. the third power level transitions from the first power level, and the second power level transitions from the third power level; the fourth power level begins simultaneously with the transition from the third power level to the second power level and ends before the end of the second power level; 15. The plasma processing apparatus of claim 14, wherein the sixth power level starts simultaneously with the end of the fourth power level or after a predetermined time has elapsed after the end of the fourth power level, and ends before the end of the second power level.

16. 9. The plasma processing apparatus of claim 8, wherein the duration of the fourth power level is 30 [mu]s or less.

17. One period of the main cycle is 10 Hz to 200 Hz, 3. The plasma processing apparatus according to claim 1, wherein one period of the first sub-cycle and the second sub-cycle is 1 kHz to 20 kHz.

18. a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an electrode disposed within the substrate support; a first RF generator coupled to the plasma processing chamber and configured to generate a first RF pulse signal including a plurality of main cycles, each main cycle including a first period and a second period, the first period including a plurality of first sub-cycles, and the second period including a plurality of second sub-cycles, the first RF pulse signal having two or more different power levels in each of the plurality of first sub-cycles and the plurality of second sub-cycles; a second RF generator coupled to the electrode and configured to generate a second RF pulse signal comprising the plurality of main cycles, the second RF pulse signal having two or more different power levels in each of the plurality of first sub-cycles and a zero power level in the second period; and the first RF pulse signal has a first power level and a second power level; the second RF pulse signal has a third power level and a fourth power level; The plasma processing apparatus, wherein the period of the first power level does not overlap with the period of the third power level.

19. the first RF pulse signal has a first frequency; 20. The plasma processing apparatus of claim 18, wherein the second RF pulse signal has a second frequency lower than the first frequency.

20. 20. The plasma processing apparatus of claim 18, wherein the second power level and the fourth power level are zero power levels.

21. 20. The plasma processing apparatus of claim 18, wherein the duration of the third power level is 30 [mu]s or less.

22. One period of the main cycle is 10 Hz to 200 Hz, 20. The plasma processing apparatus according to claim 18, wherein one period of the first sub-cycle and the second sub-cycle is 1 kHz to 20 kHz.

23. A plasma processing method using a plasma processing apparatus, comprising: The plasma processing apparatus includes: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an electrode disposed within the substrate support; an antenna disposed above the substrate support; Equipped with The plasma processing method includes a plurality of main cycles, each of which includes a first period and a second period, and the first period includes a plurality of first sub-cycles, each of which includes: periodically supplying a first RF pulse signal having three or more different power levels to the antenna; periodically applying a second RF pulse signal having two or more different power levels to the electrode; periodically supplying a third RF pulse signal having two or more different power levels to the electrode; The second period is periodically supplying the first RF pulse signal to the antenna without supplying the second RF pulse signal and the third RF pulse signal to the electrode. Plasma treatment method.

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