Plasma treatment method and plasma treatment device

Abstract

The plasma processing method of the present invention includes the following steps: a step of placing a substrate on a substrate support portion; a step of supplying a processing gas for processing the substrate into a processing chamber; a step of generating plasma of the processing gas in the processing chamber by means of a first radio frequency signal and a second radio frequency signal; and a step of applying a bias signal to the substrate support portion; the step of generating plasma includes a step of superimposing the second radio frequency signal on the first radio frequency signal according to the time point at which the bias signal is applied to the substrate support portion.

Description

Technical Field

[0001] The embodiments illustrated in this invention relate to plasma treatment methods and plasma treatment apparatus. Prior Technology

[0002] As a technique for controlling the quantity and quality of free radicals and ions, a plasma treatment device has been described in Patent Document 1. [Known Technical Documents] [Patent Literature]

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-004710 Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] This invention provides a technique that can mitigate the effects of radio frequency reflection. [Technical means to solve the problem]

[0006] In one exemplary embodiment of the present invention, a plasma processing method is provided, wherein a substrate is plasma processed in a plasma processing apparatus. The plasma processing apparatus includes: a processing chamber; and a substrate support portion disposed within the processing chamber to support the substrate. The plasma processing method includes the following steps: placing the substrate in the substrate support portion; supplying a processing gas for processing the substrate to the processing chamber; generating plasma of the processing gas in the processing chamber using a first radio frequency signal and a second radio frequency signal; and supplying a bias signal to the substrate support portion. The plasma generation step includes superimposing the second radio frequency signal onto the first radio frequency signal based on the timing at which the bias signal is supplied to the substrate support portion.

[0007] In one exemplary embodiment of the present invention, a plasma processing apparatus is provided. The plasma processing apparatus includes: a processing chamber; a substrate support disposed within the processing chamber and configured to support the substrate; and a control unit; the control unit performs the following controls: placing the substrate on the substrate support; supplying processing gas for processing the substrate into the processing chamber; generating plasma of the processing gas in the processing chamber using a first radio frequency signal and a second radio frequency signal; applying a bias signal to the substrate support; and superimposing the second radio frequency signal onto the first radio frequency signal according to the timing at which the bias signal is supplied to the substrate support. [Effects of the Invention]

[0008] According to an exemplary embodiment of the present invention, a technique can be provided to mitigate the effects of radio frequency reflection. Simple Explanation of the Diagram

[0009] [Figure 1] A schematic diagram of a substrate processing apparatus 1 in an exemplary embodiment. [Figure 2] A partial enlarged view of an example of a substrate support section 11 included in the substrate processing apparatus 1. [Figure 3] shows a flowchart of one example of an embodiment of the plasma processing method. [Figure 4] shows a timing diagram of one example of the various source radio frequency signals and bias signals in this processing method. [Figure 5A] shows an example of an electrical pulse P1 contained in a bias DC signal. [Figure 5B] shows an example of an electrical pulse P1 contained in a bias DC signal. [Figure 5C] shows a diagram of an example of an electrical pulse P1 contained in a bias radio frequency signal. [Figure 6] shows a diagram of an example of an electrical pulse P2 contained in the second source radio frequency signal. [Figure 7] shows a diagram of an example of an electrical pulse P3 contained in the third source radio frequency signal. [Figure 8] shows a timing diagram of another example of this processing method. [Figure 9] shows a timing diagram of another example of this processing method. [Figure 10] shows a timing diagram of another example of this processing method. [Figure 11] shows a timing diagram of another example of this processing method. [Figure 12] shows a timing diagram of another example of this processing method. [Figure 13] shows a timing diagram of another example of this processing method. [Figure 14] shows a timing diagram of another example of this processing method. [Figure 15] shows a timing diagram of another example of this processing method. [Figure 16] shows a timing diagram of another example of this processing method. [Figure 17] shows a timing diagram of another example of this processing method. [Figure 18] shows a timing diagram of another example of this processing method. [Figure 19] shows a timing diagram of another example of this processing method. [Figure 20] shows a timing diagram of another example of this processing method. [Figure 21] shows a timing diagram of another example of this processing method. [Figure 22] shows a timing diagram of another example of this processing method. [Figure 23] shows a timing diagram of another example of this processing method. [Figure 24] shows a timing diagram of another example of this processing method. [Figure 25] shows a timing diagram of another example of this processing method. Implementation

[0010] The following describes various embodiments of the present invention.

[0011] In one exemplary embodiment, a plasma processing method is provided for plasma processing a substrate in a plasma processing apparatus. The plasma processing apparatus includes a processing chamber and a substrate support disposed within the processing chamber to support the substrate. The plasma processing method includes the following steps: placing the substrate in the substrate support; supplying a processing gas for processing the substrate to the processing chamber; generating plasma of the processing gas in the processing chamber using a first radio frequency signal and a second radio frequency signal; and supplying a bias signal to the substrate support. The plasma generation step includes superimposing the second radio frequency signal onto the first radio frequency signal based on the timing at which the bias signal is applied to the substrate support.

[0012] In one exemplary embodiment, the bias signal is a pulse wave that periodically includes a first electrical pulse; the first radio frequency signal is a continuous wave of radio frequency having a first frequency; the second radio frequency signal is a pulse wave that periodically includes a second electrical pulse; and the second electrical pulse is composed of radio frequency having a second frequency different from the first frequency.

[0013] In one exemplary embodiment, the first electrical pulse is constituted by comprising one or more pulse voltages.

[0014] In one exemplary embodiment, the first electrical pulse is constituted by a continuous wave of radio frequency.

[0015] In one exemplary embodiment, the period during which the first electrical pulse repeatedly occurs in the bias signal, i.e., the first cycle, is equal to the period during which the second electrical pulse repeatedly occurs in the second radio frequency signal, i.e., the second cycle.

[0016] In one exemplary embodiment, during the plasma generation step, a first radio frequency signal and a second radio frequency signal are supplied to the substrate support.

[0017] In one exemplary embodiment, the timing of the second electrical pulse is the same as the timing of the first electrical pulse stopping.

[0018] In one exemplary embodiment, the second electrical pulse occurs earlier than the first electrical pulse stops.

[0019] In one exemplary embodiment, the second electrical pulse occurs later than the first electrical pulse stops.

[0020] In one exemplary embodiment, the period during which the second electrical pulse stops in the second cycle is equal to the period during which the first electrical pulse occurs in the first cycle.

[0021] In one exemplary embodiment, the period during which the second electrical pulse stops in the second cycle is longer than the period during which the first electrical pulse occurs in the first cycle.

[0022] In one exemplary embodiment, the period during which the second electrical pulse stops in the second cycle is shorter than the period during which the first electrical pulse occurs in the first cycle.

[0023] In one exemplary embodiment, the timing of the second electrical pulse is the same as the timing of the first electrical pulse.

[0024] In one exemplary embodiment, the second electrical pulse occurs earlier than the first electrical pulse.

[0025] In one exemplary embodiment, the second electrical pulse occurs later than the first electrical pulse.

[0026] In one exemplary embodiment, the period during which the second electrical pulse is supplied in the second cycle is equal to the period during which the first electrical pulse occurs in the first cycle.

[0027] In one exemplary embodiment, the second electrical pulse is supplied for a longer period in the second cycle than the first electrical pulse occurs in the first cycle.

[0028] In one exemplary embodiment, the second electrical pulse is supplied during a shorter period in the second cycle than the first electrical pulse occurs during the first cycle.

[0029] In one exemplary embodiment, the plasma generation step includes the step of further superimposing the third radio frequency signal on the first radio frequency signal according to the timing of the bias signal being supplied to the substrate support.

[0030] In one exemplary embodiment, the third radio frequency signal is a pulse wave that periodically includes a third electrical pulse; the third electrical pulse is composed of a radio frequency having a third frequency different from the first and second frequencies; at least a portion of the third electrical pulse overlaps with the second electrical pulse in time and overlaps with the first radio frequency signal.

[0031] In one exemplary embodiment, the third radio frequency signal is a pulse wave that periodically includes a third electrical pulse; the third electrical pulse is composed of a radio frequency having a third frequency different from the first and second frequencies; the third electrical pulse does not overlap with the second electrical pulse in time, but overlaps with the first radio frequency signal.

[0032] In one example implementation, the second frequency is an integer multiple of the first frequency.

[0033] In one exemplary implementation, the pulse voltage includes a negative voltage.

[0034] In one exemplary embodiment of the present invention, a plasma processing apparatus is provided. The plasma processing apparatus includes: a processing chamber; a substrate support disposed within the processing chamber and configured to support the substrate; and a control unit; the control unit performs the following controls: placing the substrate in the substrate support; supplying processing gas for processing the substrate into the processing chamber; generating plasma of the processing gas in the processing chamber using a first radio frequency signal and a second radio frequency signal; applying a bias signal to the substrate support; and superimposing the second radio frequency signal onto the first radio frequency signal according to the timing at which the bias signal is applied to the substrate support.

[0035] The following will describe in detail the various embodiments of the present invention with reference to the drawings. Furthermore, in each drawing, the same or identical elements will be labeled with the same symbol, and repeated descriptions will be omitted. Unless otherwise stated, the positional relationships (top, bottom, left, right, etc.) shown in the drawings will be explained. The scale ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to those shown in the drawings.

[0036] Figure 1 is a schematic diagram showing an exemplary embodiment of a substrate processing apparatus 1. The substrate processing apparatus 1 is a capacitively coupled plasma processing apparatus. The substrate processing apparatus 1 includes: a plasma processing chamber 10, a gas supply unit 20, a power supply 30, an exhaust system 40, and a control unit 50. Furthermore, the substrate processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a gas diffusion disk 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The gas diffusion disk 13 is disposed above the substrate support unit 11. In one exemplary embodiment, the gas diffusion disk 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the gas diffusion disk 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one type of processing gas to the plasma processing space 10s, and at least one gas outlet for discharging gas from the plasma processing space. The sidewall 10a is grounded. The gas diffusion disk 13 and the substrate support portion 11 are electrically insulated from the shell system of the plasma processing chamber 10.

[0037] Figure 2 is a partially enlarged view of an example of a substrate support portion 11 included in the substrate processing apparatus 1. The substrate support portion 11 includes a main body 111 and an annular assembly 112. The main body 111 includes a base 113, an electrostatic chuck 114, and an electrode plate 117. Furthermore, the main body 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W, and an annular region (annular support surface) 111b for supporting the annular assembly 112. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 when viewed from above. The substrate W is disposed on the central region 111a of the main body 111; the annular assembly 112 is disposed on the annular region 111b of the main body 111, surrounding the substrate W on the central region 111a of the main body 111. The base 113 may also include a conductive member. The conductive components of the base 113 function as the lower electrode. An electrostatic chuck 114 is disposed on the base. The top surface of the electrostatic chuck 114 has a substrate support surface 111a. The ring assembly 112 includes one or more ring-shaped components. Among the one or more ring-shaped components, at least one is an edge ring.

[0038] The electrostatic chuck 114 includes a chuck electrode 115 and a bias electrode 116. The chuck electrode 115 has an electrode 115a disposed between the substrate support surface 111a and the base 113. Electrode 115a may also be a planar electrode corresponding to the shape of the substrate support surface 111a. Furthermore, the chuck electrode 115 may also have electrodes 115b and 115c disposed between the ring assembly 112 and the base 113. Electrodes 115b and c may also be annular electrodes corresponding to the shape of the ring assembly 112. Furthermore, electrode 115c is disposed outside electrode 115b. The bias electrode 116 has an electrode 116a disposed between electrode 115a (or substrate support surface 111a) and the base 113. Electrode 116a may also be a planar electrode corresponding to the shape of the substrate support surface 111a and / or electrode 115a. Furthermore, the bias electrode 116 may also have an electrode 116b disposed between the ring assembly and the base 113.

[0039] Furthermore, when the conductive component included in the base 113 functions as a lower electrode, the electrostatic chuck 114 may not include the bias electrode 116. Moreover, the chuck electrode 115 may also function as a lower electrode. When the chuck electrode 115 functions as a lower electrode, the electrostatic chuck 114 may not include the bias electrode 116. Furthermore, the electrostatic chuck 114 may be configured with different components for the portion containing electrodes 115a and 116a and the portion containing electrodes 115b, 115c, and 116b.

[0040] Furthermore, although the illustration is omitted, the substrate support portion 11 may also include a temperature control module, configured to adjust at least one of the electrostatic chuck 114, the ring assembly 112, and the substrate to a target temperature. The temperature control module may also include a heater, a heat transfer medium, a flow path, or a combination thereof. In the flow path, a heat transfer fluid such as brine or gas flows. Furthermore, the substrate support portion 11 may also include a heat transfer gas supply portion, configured to supply heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0041] Returning to Figure 1, the gas diffusion disk 13 is configured to introduce at least one type of processing gas from the gas supply unit 20 into the plasma processing space within 10 seconds. The gas diffusion disk 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space within 10 seconds through the plurality of gas inlets 13c. Furthermore, the gas diffusion disk 13 includes a conductive member. The conductive member of the gas diffusion disk 13 functions as an upper electrode. In addition to the gas diffusion disk 13, the gas inlet may also include one or more side gas injectors (SGIs), which are installed in one or more openings formed in the sidewall 10a.

[0042] The gas supply unit 20 may also 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 type of process gas from its respective gas source 21, via its respective flow controller 22, to the gas diffuser 13. Each flow controller 22 may also include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include one or more flow modulation elements for regulating or pulsed flow of the at least one type of process gas.

[0043] The power supply 30 includes a radio frequency (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 at least one type of RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive members of the substrate support 11 and / or the conductive members of the gas diffusion disk 13. This generates plasma from at least one type of processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 functions as at least a portion of the plasma generation unit, which is configured to generate plasma from one or more processing gases in the plasma processing chamber 10. 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, allowing ionic components in the formed plasma to be introduced into the substrate W.

[0044] In one exemplary embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is configured to be coupled to a conductive member of the substrate support 11 and / or a conductive member of the gas diffusion disk 13 via at least one impedance matching circuit to generate a source RF signal (source RF power) for plasma generation. In one exemplary embodiment, the source RF signal is a continuous wave or a pulse wave, configured to include RF signals with frequencies in the range of 13MHz to 150MHz. In one exemplary embodiment, the first RF generation unit 31a may also be configured to generate a plurality of source RF signals with different frequencies. The generated one or more source RF signals are supplied to the conductive members of the substrate support 11 and / or the gas diffusion disk 13. The one or more source RF signals may also be supplied from the substrate support 11 to the base 113, the suction cup electrode 115, or the bias electrode 116. The second radio frequency (RF) generation unit 31b is configured to be coupled to a conductive member of the substrate support unit 11 via at least one impedance matching circuit to generate a bias RF signal (bias RF power). In one exemplary embodiment, the bias RF signal has a frequency lower than that of the source RF signal. In one exemplary embodiment, the bias RF signal is a continuous wave or a pulse wave, configured to include RF signals with frequencies in the range of 400 kHz to 13.56 MHz. In one exemplary embodiment, the second RF generation unit 31b may also be configured to generate a plurality of bias RF signals with different frequencies. The generated one or more bias RF signals are supplied to the base 113, chuck electrode 115, or bias electrode 116 of the substrate support unit 11. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0045] Furthermore, the power supply 30 may also include a direct current (DC) power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one exemplary embodiment, the first DC generating unit 32a is configured to be connected to a conductive member of the substrate support 11 to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one exemplary embodiment, the first DC signal may also be applied to electrodes 116a and / or 116b included in the base 113, chuck electrode 115, or bias electrode 116 of the substrate support 11. In one exemplary embodiment, the second DC generating unit 32b is configured to be connected to a conductive member of the gas diffusion disk 13 to generate a second DC signal. The generated second DC signal is applied to the conductive member of the gas diffusion disk 13. In various embodiments, at least one of the first and second DC signals can be pulsed. Furthermore, the first and second DC generating units 32a and 32b can be externally connected to the radio frequency power supply 31, or the first DC generating unit 32a can replace the second radio frequency generating unit 31b.

[0046] The DC power supply 32 generates a DC voltage applied to electrodes 115a, 115b, and 115c included in the chuck electrode 115 (see Figure 2). Electrodes 115b and 115c can also be configured as bipolar electrostatic chucks. Alternatively, electrodes 115a, 115b, and 115c can be integrated as a single unit. The DC power supply 32 can also be configured to apply different DC voltages to electrodes 115a, 115b, and 115c, or it can be configured to apply the same DC voltage. Furthermore, the power supply 30 can also be a power supply different from the DC power supply 32, but generating a voltage applied to the chuck electrode 115.

[0047] The exhaust system 40 can be connected to a gas outlet 10e, for example, located at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may also include a turbomolecular pump, a dry pump, or a combination thereof.

[0048] The control unit 50 processes instructions executable by a computer to cause the substrate processing apparatus 1 to perform the various steps described herein. The control unit 50 may be configured to control each component of the substrate processing apparatus 1 to perform the various steps described herein. In one exemplary embodiment, part or all of the control unit 50 may also be provided as part of an external device of the substrate processing apparatus 1. The control unit 50 may include, for example, a computer 50a. The computer 50a may include, for example, a processing unit (CPU: Central Processing Unit) 50a1, a memory unit 50a2, and a communication interface 50a3. The processing unit 50a1 may be configured to perform various control operations according to a program stored in the memory unit 50a2. The memory unit 50a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 50a3 can communicate with another component of the substrate processing device 1 via a communication line such as a LAN (Local Area Network).

[0049] Furthermore, the plasma formed in the plasma processing space can be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR), helicon wave plasma (HWP), or surface wave plasma (SWP), in addition to capacitively coupled plasma (CCP). Moreover, various types of plasma generators, including alternating current (AC) and direct current (DC) plasma generators, can be used. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes radio frequency (RF) signals and microwave signals. In one embodiment, the radio frequency signal has a frequency in the range of 200 kHz to 150 MHz.

[0050] Figure 3 is a flowchart illustrating an exemplary embodiment of the plasma processing method (hereinafter sometimes referred to as "this processing method"). Figure 4 shows an example timing diagram of the first, second, and third source radio frequency signals and the bias DC signal in this processing method. Figures 5A to 5C are diagrams showing an example of an electrical pulse P1 contained in the bias signal. Figure 6 is a diagram showing an example of an electrical pulse P2 contained in the second source radio frequency signal. Figure 7 is a diagram showing an example of an electrical pulse P3 contained in the third source radio frequency signal. In Figures 4 to 7, the horizontal axis displays time. Furthermore, in Figures 4 to 7, the vertical axis displays the power level of each source radio frequency signal (as an example, the actual power value of each source radio frequency signal) and / or the voltage, voltage level, or power level of the bias signal.

[0051] In Figure 4, the bias DC signal is an example of a bias signal. The "VL" and "VH" values ​​of the bias DC signal indicate the voltage level of the bias DC signal (as an example, the actual voltage value of the bias DC signal). In the example shown in Figure 4, the bias voltage applied to the substrate support 11 by the bias DC signal is greater during the H period than during the L period. Furthermore, as will be discussed later in Figure 5C, the bias signal can be a bias radio frequency signal.

[0052] Furthermore, in Figure 4, "L1" for the first source radio frequency signal (an example of "first radio frequency signal") indicates that the power level of the radio frequency constituting the first source radio frequency signal is zero or lower than the power level indicated by "H1". Similarly, in Figure 4, "L2" for the second source radio frequency signal (an example of "second radio frequency signal") indicates that the power level of the radio frequency constituting the second source radio frequency signal is zero or lower than the power level indicated by "H2". "L3" for the third source radio frequency signal (an example of "third radio frequency signal") indicates that the power level of the radio frequency constituting the third source radio frequency signal is zero or lower than the power level indicated by "H3".

[0053] As shown in Figure 3, this processing method includes the following steps: placing the substrate W on the substrate support 11 (ST1), supplying processing gas to the plasma processing chamber 10 (ST2), periodically supplying the substrate support 11 with a first source radio frequency signal (an example of the first radio frequency signal) (ST3), periodically supplying the substrate support 11 with a second source radio frequency signal (an example of the second radio frequency signal) (ST4), supplying the substrate support 11 with a third source radio frequency signal (an example of the third radio frequency signal) (ST5), supplying a bias signal (ST6), determining the end of etching (ST7), and stopping the supply of each signal (the first, second, and third source radio frequency signals and the bias signal) and processing gas (ST8).

[0054] In step ST1, the substrate W is disposed on the substrate support portion 11. The substrate W may be, for example, a substrate on a silicon wafer having a base film deposited thereon, an etched film to be etched by this processing method, or a mask film having a predetermined pattern. The etched film may be, for example, a dielectric film, a semiconductor film, or a metal film.

[0055] In step ST2, processing gas is supplied to the plasma processing chamber 10. The processing gas is the gas used to etch the film formed on the substrate W. The type of processing gas can be appropriately selected according to the material of the film to be etched, the material of the mask film, the material of the base film, the pattern of the mask film, the etching depth, etc.

[0056] In steps ST3 to ST5, first, second, and third source radio frequency signals are supplied to the substrate support 11. The first radio frequency generation unit 31a can generate each source radio frequency signal as a different signal and supply it to the substrate support 11, or it can supply the substrate support 11 with a single signal composed of a composite wave synthesized from the waveforms of each source radio frequency signal.

[0057] The first source radio frequency signal, as an example, is a continuous wave of radio frequency with a power level of H1. The second source radio frequency signal, as shown in Figure 6, is a signal that alternates between periods L and H. Period L is the period when the power level of the radio frequency constituting the second source radio frequency signal is low, and period H is the period when the power level is high. Furthermore, the third source radio frequency signal, as shown in Figure 7, is a signal that alternates between periods L and H. Period L is the period when the power level of the radio frequency constituting the third source radio frequency signal is low, and period H is the period when the power level is high. That is, both the second and third source radio frequency signals, during period H, are pulse waves containing electrical pulses composed of radio frequency components.

[0058] Each radio frequency (RF) constituting the first, second, and third source RF signals can have a different frequency. For example, the frequency of each RF constituting the first, second, and third source RF signals can be in the range of 1 to 200 MHz. Furthermore, the frequency of each RF can be any one of 13.56 MHz, 40.68 MHz, 60 MHz, and 100 MHz. The frequencies of each RF constituting the first, second, and third source RF signals are, for example, 40.68 MHz, 60 MHz, and 100 MHz, respectively. Each RF constituting the first, second, and third source RF signals can be an integer multiple of a certain frequency. In this processing method, the second and / or third source RF signals are superimposed on the first source RF signal to form a composite wave. In the example shown in Figure 4, the two source RF signals (the second and third source RF signals) are superimposed on the first source RF signal to form a composite wave. The number of radio frequency signals superimposed on the first source radio frequency signal can be one or more; furthermore, it can be three or more. Furthermore, the frequency of the source radio frequency signals superimposed on the first source radio frequency signal (e.g., the second and third source radio frequency signals) can be modulated according to the frequency at which the pulse voltage P repeatedly appears in the bias DC signal, or the frequency of the radio frequency contained in the bias radio frequency signal. For example, the modulation range of the frequency of the source radio frequency signals superimposed on the first source radio frequency signal (e.g., the second and third source radio frequency signals) can be the frequency at which the pulse voltage P repeatedly appears in the bias DC signal, or a range with the frequency of the radio frequency contained in the bias radio frequency signal as the upper and lower limits. For example, if the frequency of the second source radio frequency signal is 40.68MHz and the frequency at which the pulse voltage P repeatedly appears in the bias DC signal is 400kHz, the frequency of the second source radio frequency signal can also be modulated within the range of 40.68MHz ± 400kHz.

[0059] Once the first, second, and / or third source radio frequency signals are supplied to the substrate support 11, plasma is formed from the processing gas supplied to the plasma processing chamber 10. In other embodiments, the source radio frequency signals can also be supplied to the upper electrode included in the gas diffusion disk 13. Furthermore, this processing method can be performed not only using the capacitively coupled substrate processing apparatus 1, but also using a substrate processing apparatus employing any plasma source such as inductively coupled plasma or microwave plasma. In this case, the first, second, and / or third source radio frequency signals can also be supplied to any electrode or coil included in each substrate processing apparatus.

[0060] In step ST6, a bias signal is applied to the substrate support portion 11. As an example, when the bias signal is a DC bias signal, as shown in FIG4, the DC bias signal can be a pulse wave that alternates between periods H and L; during period H, the effective voltage value is VL; during period L, the effective voltage value is VH, which is higher than VL. For example, the DC bias signal during period H includes an electrical pulse P1 with an effective voltage value of negative. The electrical pulse P1 appears periodically in the bias signal. The frequency at which the electrical pulse P1 repeatedly appears in the DC bias signal can be 10Hz to 2MHz. Furthermore, this frequency can be 10Hz to 100kHz. In one example, this frequency is the reciprocal of the period PDa in FIG4. As shown in FIG4, in the DC bias signal, the electrical pulse P1 appears periodically with a period PDa as one cycle. As shown in FIG5A and FIG5B, the electrical pulse P1 can include one or more pulse voltages P. Figure 5A shows an example where the electrical pulse P1 contains two or more pulse voltages P. Furthermore, Figure 5B shows an example where the electrical pulse P1 contains only one pulse voltage P.

[0061] As shown in Figures 5A and 5B, as an example, the bias DC signal during period L can be a fixed voltage V1 (=VH). V1 can be 0V, a positive voltage, or a negative voltage. Furthermore, as an example, as shown in Figure 5A, during period H of the bias DC signal, the electrical pulse P1 of the bias DC signal can be composed of periodically repeating pulse voltage P. In the example shown in Figure 5A, the frequency at which the pulse voltage P repeatedly appears in the bias DC signal can be 50kHz to 2MHz. Furthermore, this frequency can be 100kHz to 800kHz. In one example, this frequency is the reciprocal of the sum of the period during which one pulse voltage P appears and the period during which the pulse voltage P stops, as shown in Figure 5A. Furthermore, as shown in Figure 5B, during period L of the bias DC signal, the electrical pulse P1 of the bias DC signal can be composed of one pulse voltage P. In the example shown in Figure 5B, the frequency at which the bias DC signal pulse voltage P or electrical pulse P1 repeatedly occurs can be 50kHz to 2MHz. Furthermore, this frequency can be 100kHz to 800kHz. In one example, this frequency is the reciprocal of the sum of periods Ta1 and Ta2 in Figure 5B. In the examples shown in Figures 5A and 5B, the pulse voltage P includes V2, which is a voltage lower than V1. V2 can be a negative voltage. Furthermore, the waveform displayed by the one or more pulse voltages P included in the electrical pulse P1, besides the rectangular wave shown in Figure 5, can be any waveform such as a triangular wave, trapezoidal wave, or impulse wave, where the voltage changes with a fixed period, thus applying a predetermined bias voltage to the upper electrode or substrate support 11.

[0062] As shown in Figure 5C, the bias signal can also be a bias radio frequency (RF) signal. In the example shown in Figure 5C, the bias RF signal, during period H, can be a pulse wave containing an electrical pulse P1. The electrical pulse P1 can be composed of a continuous RF wave. That is, in the example shown in Figure 5C, the bias RF signal can be a signal that alternates between periods H and L, where period H is the period with a high power level of the RF signal constituting the bias RF signal, and period L is the period with a low power level. The power level of the bias RF signal can be zero during period L. Furthermore, the frequency of the RF signal contained in the electrical pulse P1 can be, for example, 50kHz to 15MHz. Alternatively, this frequency can be 200kHz to 15MHz. Furthermore, the frequency at which the electrical pulse P1 repeatedly appears in the bias RF signal can be 10Hz to 2MHz. Alternatively, this frequency can be 10Hz to 100kHz.

[0063] Furthermore, steps ST3 to ST6 can begin simultaneously, or they can begin at different times. When steps ST3 to ST6 begin at different times, their order can be any.

[0064] In step ST7, a decision is made as to whether to end the etching process of the etched film. If the etching process is to continue, the process returns to step ST3 and continues from step ST3 to step ST7. On the other hand, if the etching process is to be ended, the supply of all signals and processing gas is stopped in step ST8, thus ending the etching process.

[0065] Figures 4 and 8 to 25 show examples of timing diagrams for the bias DC signal, which is one example of a bias signal, and the first, second, and third source RF signals, in steps ST3 to ST6. Figures 4 and 8 to 25 show a portion of the execution of steps ST3 to ST6. The relationship between the signals in steps ST3 to ST6 will be explained below with reference to Figures 4 and 8 to 25. Furthermore, in the examples shown in Figures 4 and 8 to 25, a bias RF signal may also be supplied to the substrate support portion 11 instead of the bias DC signal.

[0066] Figure 4 is a timing diagram showing one example of this processing method. In this example, once the first, second, and / or third source radio frequency signals are supplied to the substrate support 11, a plasma of the processing gas is generated in the plasma processing chamber 10. On the other hand, the bias DC signal includes: during period H, an electrical pulse P1 is included, which is composed of a pulse voltage P (refer to Figures 5A and 5B); and during period L, its voltage level is fixed. Then, during period H, once the electrical pulse P1 (i.e., pulse voltage P) of the bias DC signal is applied to the substrate support 11, the active species present in the plasma generated by the first, second, and / or third source radio frequency signals are attracted to the substrate W disposed on the substrate support 11. Thereby, positive ions collide with the etched film formed on the substrate W, and the etched film is etched.

[0067] Specifically, at time t1, the voltage level of the bias DC signal is VL. Consequently, an electrical pulse P1 appears in the bias DC signal, and this electrical pulse P1 is applied to the substrate support 11 (hereinafter, the appearance of the electrical pulse P1 in the bias signal is sometimes referred to as "electrical pulse P1 on"). Then, the electrical pulse P1 is applied to the substrate support 11 for the period from time t1 to time t2 (period Ta1). Once the electrical pulse P1 is applied to the substrate support 11, the active species present in the plasma are attracted to the substrate W disposed on the substrate support 11. Thereby, positive ions collide with the etched film formed on the substrate W, and the etched film is etched.

[0068] At time t2, once the voltage level of the bias DC signal becomes VH, the electrical pulse P1 stops, thus ceasing the application of electrical pulse P1 to the substrate support 11 (hereinafter, the cessation of electrical pulse P1 in the bias signal is sometimes referred to as "electrical pulse P1 off"). Then, at time t3, after a period Ta2 has elapsed from time t2, one cycle of the bias DC signal, i.e., a period PDa, ends. Furthermore, at time t3, the voltage level of the bias DC signal becomes VL again, and the next cycle of the bias DC signal begins.

[0069] The second source radio frequency (RF) signal is phase-synchronized with the bias DC signal, causing its power level to change periodically. In the example shown in Figure 4, firstly, from time 0 to time t1, the voltage level of the second source RF signal is H2. Consequently, an electrical pulse P2 (refer to Figure 6) containing radio frequency components appears in the second source RF signal and is supplied to the substrate support 11 (hereinafter, the appearance of electrical pulse P2 in the second source RF signal is sometimes referred to as "electrical pulse P2 on"). Then, at time t1, once the bias DC signal's electrical pulse P1 is on, the voltage level of the second source RF signal becomes L2. Consequently, the electrical pulse P2 of the second source RF signal stops, and the supply of electrical pulse P2 to the substrate support 11 ceases (hereinafter, the cessation of electrical pulse P2 in the second source RF signal is sometimes referred to as "electrical pulse P2 off").

[0070] At time t2, after a period of Tb1 from time t1, once electrical pulse P1 is turned off, electrical pulse P2 of the second source RF signal will be turned on. Then, at time t3, after a period of Tb2 from time t2, one cycle of the second source RF signal, i.e., PDb, will end. Furthermore, at time t3, the next cycle of the second source RF signal will begin. At time t4, electrical pulse P2 of the second source RF signal will be turned on again.

[0071] The third source radio frequency (RF) signal is phase-synchronized with the bias DC signal, causing its power level to change periodically. In the example shown in Figure 4, firstly, from time 0 to time t1, the voltage level of the third source RF signal is H3. Consequently, an electrical pulse P3 (refer to Figure 7) containing radio frequency components appears in the third source RF signal, and this electrical pulse P3 is supplied to the substrate support 11 (hereinafter, the appearance of electrical pulse P3 in the third source RF signal is sometimes referred to as "electrical pulse P3 on"). Then, at time t1, once the bias DC signal pulse is on, the voltage level of the third source RF signal becomes L3. This stops the electrical pulse P3 of the third source RF signal, thus stopping the supply of electrical pulse P3 to the substrate support 11 (hereinafter, the stopping of electrical pulse P3 in the second source RF signal is sometimes referred to as "electrical pulse P3 off").

[0072] At time t2, after the period Tc1 has elapsed from time t1, once the bias voltage pulse P1 is turned off, the third source RF signal pulse P3 will be turned on. Then, at time t3, after the period Tc2 has elapsed from time t2, one cycle of the third source RF signal, i.e., PDc, will end. Furthermore, at time t3, the next cycle of the third source RF signal will begin. At time t4, the third source RF signal pulse P3 will be turned on again.

[0073] As mentioned above, in the example shown in Figure 4, during period Ta1, an electrical pulse P1 (i.e., pulse voltage P) containing the first source radio frequency signal and the bias DC signal is supplied to the substrate support 11. On the other hand, during period Ta2 when the bias DC signal electrical pulse P1 is off, a composite wave of the radio frequencies contained in the first, second, and third source radio frequency signals is supplied to the substrate support 11. Therefore, during period Ta2 when the electrical pulse P1 is not applied to the substrate support 11, the effects of reflections of the first source radio frequency signal on plasma density can be reduced. Thus, the plasma generation efficiency by the source radio frequency signal can be improved. Furthermore, during period Ta2 when the electrical pulse P1 is not applied to the substrate support 11, plasma density can be increased while the electron temperature in the plasma is reduced. Therefore, plasma density and / or electron temperature in the plasma can be controlled according to the timing of applying the electrical pulse P1 to the substrate support 11.

[0074] Figure 8 is a timing diagram showing another example of this processing method. The example in Figure 8 differs from the example illustrated in Figure 4 in that the timing of the on / off of the electrical pulses P2 and P3 of the second and third source RF signals differs. Specifically, in the example of Figure 8, the electrical pulses P2 and P3 of the second and third source RF signals turn off Δt earlier than the on / off time t1 of the bias DC signal electrical pulse P1. In other words, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are off are Δt earlier than the on / off time Ta1 of the bias DC signal pulse voltage P1. Similarly, the electrical pulses P2 and P3 of the second and third source RF signals turn on Δt earlier than the off / off time t2 of the bias DC signal electrical pulse P1. That is, the periods Tb2 and Tc2 during which the electrical pulses P2 and P3 of the second and third source radio frequency signals are turned on are Δt earlier than the period Ta2 during which the electrical pulse P1 of the bias DC signal is turned off.

[0075] As mentioned above, in the example shown in Figure 8, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with the example in Figure 4. Furthermore, in the example shown in Figure 8, the duty ratios of the second and third source RF signals are consistent with the duty ratio of the bias DC signal. On the other hand, in the example shown in Figure 8, periods Tb1 and Tb2, and periods Tc1 and Tc2, are respectively preceded by Δt by periods Ta1 and Ta2, which differs from the example in Figure 4.

[0076] Figure 9 is a timing diagram showing another example of this processing method. The example in Figure 9 differs from the example illustrated in Figure 4 in that the timing of the on / off of the electrical pulses P2 and P3 of the second and third source RF signals differs. Specifically, in the example shown in Figure 9, the electrical pulses P2 and P3 of the second and third source RF signals turn off Δt later than the on / off time t1 of the bias DC signal electrical pulse P1. In other words, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are off are Δt later than the period Ta1 during which the bias DC signal electrical pulse P1 is on. Similarly, the electrical pulses P2 and P3 of the second and third source RF signals turn on Δt later than the off / off time t2 of the bias DC signal electrical pulse P1. That is, the periods Tb2 and Tc2 during which the electrical pulses P2 and P3 of the second and third source radio frequency signals are turned on are Δt later than the period Ta2 during which the electrical pulse P1 of the bias DC signal is turned off.

[0077] As mentioned above, in the example shown in Figure 9, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with the example shown in Figure 4. Furthermore, in the example shown in Figure 9, the duty cycles of the second and third source RF signals are equal to those of the bias DC signal, which is consistent with the example shown in Figure 4. On the other hand, in the example shown in Figure 9, periods Tb1 and Tb2, and periods Tc1 and Tc2, are Δt later than periods Ta1 and Ta2, respectively, which differs from the example shown in Figure 4.

[0078] Figure 10 is a timing diagram showing another example of this processing method. The example shown in Figure 10 differs from the example illustrated in Figure 4 in that the timing of the activation of the electrical pulses P2 and P3 of the second and third source RF signals differs. That is, in the example shown in Figure 10, the electrical pulses P2 and P3 of the second and third source RF signals are activated Δt earlier than the time t2 when the electrical pulse P1 of the bias DC signal is deactivated.

[0079] As mentioned above, the example shown in Figure 10 is consistent with the example shown in Figure 4 in that the lengths of periods PDb and PDc, as well as the start and end times, are equal to those of period PDa. On the other hand, the example shown in Figure 10 differs from the example shown in Figure 4 in that the duty cycles of the second and third source RF signals are different from those of the bias DC signal.

[0080] Figure 11 is a timing diagram showing another example of this processing method. The example shown in Figure 11 differs from the example illustrated in Figure 4 in that the timing of the shutdown of the electrical pulses P2 and P3 of the second and third source RF signals differs. That is, in the example shown in Figure 11, the electrical pulses P2 and P3 of the second and third source RF signals shut off at a time Δt later than the time t1 when the electrical pulse P1 of the bias DC signal turns on. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals turn on at the time t2 when the electrical pulse P1 of the bias DC signal turns off.

[0081] As mentioned above, in the example shown in Figure 11, the timing of the activation of the electrical pulses P2 and P3 of the second and third source RF signals is consistent with that in the example shown in Figure 4. Furthermore, in the example shown in Figure 11, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with that in the example shown in Figure 4. On the other hand, in the example shown in Figure 11, the start time of periods Tb1 and Tc1 is Δt later than the start time of period Ta1, which is different from that in the example shown in Figure 4. Furthermore, in the example shown in Figure 11, the end time of periods Tb2 and Tc2 is Δt later than the end time of period Ta2, which is different from that in the example shown in Figure 4. Furthermore, in the example shown in Figure 11, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which is different from that in the example shown in Figure 4.

[0082] Figure 12 is a timing diagram showing another example of this processing method. The example shown in Figure 12 differs from the example illustrated in Figure 4 in that the timing of the shutdown of the electrical pulses P2 and P3 of the second and third source RF signals differs. That is, in the example shown in Figure 12, the electrical pulses P2 and P3 of the second and third source RF signals shut down at a time Δt earlier than the time t1 when the electrical pulse P1 of the bias DC signal turns on. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals turn on at the time t2 when the electrical pulse P1 of the bias DC signal turns off. In other words, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are off begin Δt earlier than the period Ta1 during which the bias DC signal turns on, and end simultaneously with Ta1. Furthermore, the electrical pulses P2 and P3 from the second and third source radio frequency signals will turn off Δt earlier than the moment when the electrical pulse P1 of the bias DC signal turns on.

[0083] As mentioned above, in the example shown in Figure 12, the timing of the activation of the electrical pulses P2 and P3 of the second and third source RF signals is consistent with that in the example shown in Figure 4. Furthermore, in the example shown in Figure 12, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with that in the example shown in Figure 4. On the other hand, in the example shown in Figure 12, the start time of periods Tb1 and Tc1 is Δt earlier than that of period Ta1, which is different from that in the example shown in Figure 4. Furthermore, in the example shown in Figure 12, the end time of periods Tb2 and Tc2 is Δt earlier than that of period Ta2, which is different from that in the example shown in Figure 4. Furthermore, in the example shown in Figure 12, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which is different from that in the example shown in Figure 4.

[0084] Figure 13 is a timing diagram showing another example of this processing method. The example shown in Figure 13 differs from the example illustrated in Figure 4 in that the timing of the activation of the electrical pulses P2 and P3 of the second and third source RF signals differs. Specifically, in the example shown in Figure 13, the electrical pulses P2 and P3 of the second and third source RF signals activate at a time Δt later than the time t2 when the electrical pulse P1 of the bias DC signal is deactivated. That is, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are deactivated begin simultaneously with the period Ta1; furthermore, they end Δt later than the period Ta1 during which the electrical pulse P1 of the bias DC signal is activated. Moreover, the electrical pulses P2 and P3 of the second and third source RF signals deactivate at the time t3 when the electrical pulse P1 of the bias DC signal is activated.

[0085] As mentioned above, in the example shown in Figure 13, the timing of the shutdown of the electrical pulses P2 and P3 of the second and third source RF signals is consistent with that in the example shown in Figure 4. Furthermore, in the example shown in Figure 13, the lengths of periods PDb and PDc, as well as the start and end times, are equal to those of period PDa, which is consistent with that in the example shown in Figure 4. On the other hand, in the example shown in Figure 13, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which is different from that in the example shown in Figure 4.

[0086] Figure 14 is a timing diagram showing another example of this processing method. The example shown in Figure 14 differs from the example illustrated in Figure 4 in that the timing of the on and off of the electrical pulses P2 and P3 of the second and third source RF signals differs. Specifically, in the example shown in Figure 14, the electrical pulses P2 and P3 of the second and third source RF signals turn off Δt later than the onset time t1 of the bias DC signal electrical pulse P1; and turn on Δt earlier than the offset time t2 of the bias DC signal electrical pulse P1. In other words, the off-times Tb1 and Tc1 of the electrical pulses P2 and P3 of the second and third source RF signals begin Δt later than the time period Ta1; and end Δt earlier. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals turn off Δt later than the onset time t3 of the bias DC signal electrical pulse P1.

[0087] As mentioned above, the example shown in Figure 14 is consistent with the example shown in Figure 4 in that the lengths of periods PDb and PDc are equal to those of period PDa. However, the example shown in Figure 14 differs from the example shown in Figure 4 in that the on and off times of the electrical pulses P2 and P3 of the second and third source RF signals are different. Furthermore, the example shown in Figure 14 differs from the example shown in Figure 4 in that the duty cycle of the second and third source RF signals is different from the duty cycle of the bias DC signal.

[0088] Figure 15 is a timing diagram showing another example of this processing method. The example shown in Figure 15 differs from the example illustrated in Figure 4 in that the timing of the on and off of the electrical pulses P2 and P3 of the second and third source RF signals differs. Specifically, in the example shown in Figure 15, the electrical pulses P2 and P3 of the second and third source RF signals turn off Δt earlier than the onset time t1 of the bias DC signal electrical pulse P1; and turn on Δt later than the offset time t2 of the bias DC signal electrical pulse P1. In other words, the off periods Tb1 and Tc1 of the electrical pulses P2 and P3 of the second and third source RF signals begin Δt earlier than the period Ta1; and end Δt later. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals turn off Δt earlier than the onset time t3 of the bias DC signal electrical pulse P1.

[0089] As mentioned above, the example shown in Figure 15 is consistent with the example shown in Figure 4 in that the lengths of periods PDb and PDc are equal to those of period PDa. However, the example shown in Figure 15 differs from the example shown in Figure 4 in that the on and off times of the electrical pulses P2 and P3 of the second and third source RF signals are different. Furthermore, the example shown in Figure 15 differs from the example shown in Figure 4 in that the duty cycle of the second and third source RF signals is different from the duty cycle of the bias DC signal.

[0090] In the examples shown in Figures 8 to 15, in addition to the effects achieved in the example shown in Figure 4, the on / off times of the electrical pulses P2 and P3 of the second and third source RF signals can be controlled based on the on / off time of the bias DC signal electrical pulse P1. That is, the on / off times of the electrical pulses P2 and P3 of the second and third source RF signals can be appropriately controlled according to the timing of the reflection of the first source RF signal and the on / off time of the bias DC signal electrical pulse P1, which affect plasma density. Therefore, the plasma generation efficiency caused by the source RF signals can be improved. This allows for control of plasma density and / or electron temperature.

[0091] Figure 16 is a timing diagram showing another example of this processing method. In the example shown in Figure 16, compared with the example illustrated in Figure 4, the phases of the second and third source RF signals are opposite. That is, in the example shown in Figure 16, at the time when the bias DC signal pulse P1 turns on or off, the electrical pulses P2 and P3 of the second and third source RF signals also turn on or off.

[0092] At time t1, simultaneously with the activation of the bias DC signal pulse P1, the second and third source RF signal pulses P2 and P3 are activated. Then, at time t2, after a period Ta1 (Tb1, Tc1) from time t1, once the bias DC signal pulse P1 is deactivated, the second and third source RF signal pulses P2 and P3 are deactivated. Then, at time t3, after a period Ta2 (Tb2, Tc2) from time t2, one cycle of the bias DC signal and the second and third source RF signals, i.e., cycle PDa (PDb, PDc), ends. Furthermore, at time t3, the next cycle of the bias DC signal and the second and third source RF signals begins.

[0093] As mentioned above, in the example shown in Figure 16, during the period Ta1 when the bias DC signal pulse P1 is turned on, the composite wave of the first, second, and / or third source radio frequency signals is supplied to the substrate support 11 along with the pulse P1. That is, during the period Ta1 when the bias DC signal pulse P1 is turned on, that is, at the time when the active species in the plasma are attracted to the substrate W by the pulse P1, the second and third source radio frequency signals are superimposed on the first source radio frequency signal and supplied to the substrate support 11. In this way, the plasma density can be increased at the time when the active species in the plasma are attracted to the substrate W. Furthermore, the electron temperature in the plasma can be increased. Furthermore, in the example shown in Figure 16, at the time when the bias DC signal pulse P1 is turned on, the composite wave of the first, second, and / or third source radio frequency signals is supplied. Here, the first, second, and / or third source radio frequency signals may each have different frequencies. That is, at the moment when the bias DC signal pulse P1 is turned on, a source radio frequency signal containing multiple frequencies can be supplied to the substrate support portion 11. This allows for the suppression of reflection of the composite wave of the source radio frequency signal at the moment when the bias DC signal pulse P1 is turned on. Therefore, plasma formation becomes easier. Furthermore, in the example shown in FIG16, even if the impedance changes relative to the composite wave of the first, second, and third source radio frequency signals, impedance matching can be achieved using any one of the first, second, and third source radio frequency signals. Therefore, even if the impedance changes relative to the composite wave at, for example, the moment when the bias DC signal pulse P1 is turned on, causing a change in the amount of reflection of the composite wave, the change can be suppressed.

[0094] Furthermore, in the example shown in Figure 16 (and Figures 17 to 24), as an example, during a period when the bias DC signal pulse P1 is off (i.e., period Ta2), the power levels of the first, second, and third source RF signals can simultaneously become L1, L2, and L3, respectively. In this case, any one of the power levels L1, L2, and L3 can also be made zero. Moreover, as an example, during a period when the bias DC signal pulse P1 is off (i.e., period Ta2), a composite wave with an opposite phase to the first source RF signal can be generated by the second and / or third source RF signals and superimposed on the first source RF signal. That is, a composite wave that makes the power level of the composite wave of the first, second, and third source RF signals zero can also be generated by the second and third source RF signals.

[0095] Figure 17 is a timing diagram showing another example of this processing method. In the example shown in Figure 17, compared with the example illustrated in Figure 8, the phases of the second and third source radio frequency signals are opposite.

[0096] In the example shown in Figure 17, the electrical pulses P2 and P3 of the second and third source RF signals will turn on Δt earlier than the turn-on time t1 of the bias DC signal electrical pulse P1. That is, the turn-on periods Tb1 and Tc1 of the second and third source RF signal electrical pulses P2 and P3 are Δt earlier than the turn-on period Ta1 of the bias DC signal electrical pulse P1. Similarly, the electrical pulses P2 and P3 of the second and third source RF signals will turn off Δt earlier than the turn-off time t2 of the bias DC signal electrical pulse P1. That is, the turn-on periods Tb2 and Tc2 of the second and third source RF signal electrical pulses P2 and P3 are Δt earlier than the turn-on period Ta2 of the bias DC signal electrical pulse P1.

[0097] As mentioned above, in the example shown in Figure 17, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with the example shown in Figure 16. Furthermore, in the example shown in Figure 17, the duty cycles of the second and third source RF signals are consistent with the duty cycle of the bias DC signal. On the other hand, in the example shown in Figure 17, periods Tb1 and Tb2, and periods Tc1 and Tc2, are respectively preceded by Δt by periods Ta1 and Ta2, which differs from the example shown in Figure 16.

[0098] Figure 18 is a timing diagram showing another example of this processing method. In the example shown in Figure 18, compared with the example illustrated in Figure 9, the phases of the second and third source radio frequency signals are opposite.

[0099] In the example shown in Figure 18, the electrical pulses P2 and P3 of the second and third source RF signals will turn on Δt later than the turn-on time t1 of the bias DC signal electrical pulse P1. That is, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are on are Δt later than the period Ta1 during which the bias DC signal electrical pulse P1 is on. Similarly, the electrical pulses P2 and P3 of the second and third source RF signals will turn off Δt later than the turn-off time t2 of the bias DC signal electrical pulse P1. That is, the periods Tb2 and Tc2 during which the electrical pulses P2 and P3 of the second and third source RF signals are off are Δt later than the period Ta2 during which the bias DC signal electrical pulse P1 is off.

[0100] As mentioned above, in the example shown in Figure 18, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with the example shown in Figure 16. Furthermore, in the example shown in Figure 18, the duty cycles of the second and third source RF signals are equal to those of the bias DC signal, which is consistent with the example shown in Figure 16. On the other hand, in the example shown in Figure 18, periods Tb1 and Tb2, and periods Tc1 and Tc2, are respectively delayed by Δt compared to periods Ta1 and Ta2, which differs from the example shown in Figure 16.

[0101] Figure 19 is a timing diagram showing another example of this processing method. In the example shown in Figure 19, compared with the example illustrated in Figure 10, the phases of the second and third source radio frequency signals are opposite.

[0102] In the example shown in Figure 19, the electrical pulses P2 and P3 from the second and third source radio frequency signals will turn on at the moment t1 when the electrical pulse P1 of the bias DC signal turns on. Furthermore, the electrical pulses P2 and P3 from the second and third source radio frequency signals will turn off at a moment Δt earlier than the moment t2 when the electrical pulse P1 of the bias DC signal turns off.

[0103] As mentioned above, the example shown in Figure 19 is consistent with the example shown in Figure 16 in that the lengths of periods PDb and PDc, as well as the start and end times, are equal to those of period PDa. On the other hand, the example shown in Figure 19 differs from the example shown in Figure 16 in that the duty cycles of the second and third source RF signals are different from those of the bias DC signal.

[0104] Figure 20 is a timing diagram showing another example of this processing method. In the example shown in Figure 20, compared with the example illustrated in Figure 11, the phases of the second and third source radio frequency signals are opposite.

[0105] In the example shown in Figure 20, the second and third source RF signal pulses P2 and P3 will turn on at a time Δt later than the time t1 when the bias DC signal pulse P1 turns on. Furthermore, the second and third source RF signal pulses P2 and P3 will turn off at a time t2 when the bias DC signal pulse P1 turns off. Moreover, the second and third source RF signal pulses P2 and P3 will turn on at a time Δt later than the time t3 when the bias DC signal pulse P1 turns on.

[0106] As mentioned above, in the example shown in Figure 20, the pulse turn-off times of the second and third source RF signals are consistent with those in the example shown in Figure 16. Furthermore, in the example shown in Figure 20, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with the example shown in Figure 16. On the other hand, in the example shown in Figure 20, the start times of periods Tb1 and Tc1 are Δt later than the start time of period Ta1, which differs from the example shown in Figure 16. Furthermore, in the example shown in Figure 20, the end times of periods Tb2 and Tc2 are Δt later than the end time of period Ta2, which differs from the example shown in Figure 16. Moreover, in the example shown in Figure 20, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which differs from the example shown in Figure 16.

[0107] Figure 21 is a timing diagram showing another example of this processing method. In the example shown in Figure 21, compared with the example illustrated in Figure 12, the phases of the second and third source radio frequency signals are opposite.

[0108] In the example shown in Figure 21, the electrical pulses P2 and P3 of the second and third source RF signals will turn on Δt earlier than the turn-on time t1 of the bias DC signal electrical pulse P1. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals will turn off at t2 when the bias DC signal electrical pulse P1 turns off. Moreover, the electrical pulses P2 and P3 of the second and third source RF signals will turn on Δt earlier than the turn-on time t3 of the bias DC signal electrical pulse P1.

[0109] As mentioned above, in the example shown in Figure 21, the timing of the shutdown of the electrical pulses P2 and P3 of the second and third source RF signals is consistent with that in the example shown in Figure 16. Furthermore, in the example shown in Figure 21, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with that in the example shown in Figure 16. On the other hand, in the example shown in Figure 21, the start time of periods Tb1 and Tc1 is Δt earlier than the start time of period Ta1, which differs from that in the example shown in Figure 16. Furthermore, in the example shown in Figure 21, the end time of periods Tb2 and Tc2 is Δt earlier than the end time of period Ta2, which differs from that in the example shown in Figure 16. Furthermore, in the example shown in Figure 21, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which differs from that in the example shown in Figure 16.

[0110] Figure 22 is a timing diagram showing another example of this processing method. In the example shown in Figure 22, compared with the example illustrated in Figure 13, the phases of the second and third source radio frequency signals are opposite.

[0111] In the example shown in Figure 22, the electrical pulses P2 and P3 of the second and third source RF signals will turn off at a time Δt later than the time t2 when the electrical pulse P1 of the bias DC signal turns off. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals will turn on at the time t3 when the electrical pulse P1 of the bias DC signal turns on.

[0112] As mentioned above, in the example shown in Figure 22, the timing of the shutdown of the electrical pulses P2 and P3 of the second and third source RF signals is consistent with that in the example shown in Figure 16. Furthermore, in the example shown in Figure 22, the lengths and start and end times of periods PDb and PDc are equal to those of period PDa, which is consistent with that in the example shown in Figure 16. On the other hand, in the example shown in Figure 22, the end times of periods Tb1 and Tc1 are Δt later than the end time of period Ta1, which is different from that in the example shown in Figure 16. Furthermore, in the example shown in Figure 21, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which is different from that in the example shown in Figure 16.

[0113] Figure 23 is a timing diagram showing another example of this processing method. In the example shown in Figure 23, compared with the example illustrated in Figure 16, the phases of the second and third source radio frequency signals are opposite.

[0114] In the example shown in Figure 23, the electrical pulses P2 and P3 of the second and third source RF signals will start Δt later than the start time t1 of the bias DC signal pulse; and will stop Δt earlier than the stop time t2 of the bias DC signal pulse P1. That is, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are on start Δt later than the period Ta1; and will end Δt earlier. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals will start Δt later than the start time t3 of the bias DC signal pulse P1.

[0115] As mentioned above, the example shown in Figure 23 is consistent with the example shown in Figure 16 in that the lengths of periods PDb and PDc are equal to those of period PDa. However, the example shown in Figure 23 differs from the example shown in Figure 16 in that the on and off times of the electrical pulses P2 and P3 of the second and third source RF signals are different. Furthermore, the example shown in Figure 23 differs from the example shown in Figure 16 in that the duty cycle of the second and third source RF signals is different from the duty cycle of the bias DC signal.

[0116] Figure 24 is a timing diagram showing another example of this processing method. In the example shown in Figure 24, compared to the example illustrated in Figure 15, the phases of the second and third source RF signals are opposite. That is, in the example shown in Figure 24, the electrical pulses P2 and P3 of the second and third source RF signals turn on Δt earlier than the turn-on time t1 of the bias DC signal electrical pulse P1; and turn off Δt later than the turn-off time t2 of the bias DC signal electrical pulse P1. In other words, the periods Tb1 and Tc1 during which the electrical pulses P2 and P3 of the second and third source RF signals are on begin Δt earlier than the period Ta1; and end Δt later. Furthermore, the electrical pulses P2 and P3 of the second and third source RF signals turn on Δt earlier than the turn-on time t3 of the bias DC signal electrical pulse P1.

[0117] As mentioned above, in the example shown in Figure 24, the lengths of periods PDb and PDc are equal to those of period PDa, which is consistent with the example shown in Figure 16. However, in the example shown in Figure 24, the timing of the on and off of the electrical pulses P2 and P3 of the second and third source RF signals differs from that of the example shown in Figure 16. Furthermore, in the example shown in Figure 24, the duty cycle of the second and third source RF signals differs from that of the bias DC signal, which is also different from that of the example shown in Figure 16.

[0118] In the examples shown in Figures 17 to 24, in addition to the effects achieved in the example shown in Figure 16, the timing of the on / off of the second and third source radio frequency (RF) pulses P2 and P3 can be controlled according to the on / off timing of the bias DC signal pulse P1. This allows the plasma density to increase at appropriate times, corresponding to the time when ions in the plasma are attracted to the substrate W. Furthermore, the electron temperature in the plasma can be increased. Furthermore, in the examples shown in Figures 17 to 24, the synthesized wave of the source RF signal can be supplied to the substrate support 11 at an appropriate time when the bias DC signal pulse P1 is on. This suppresses the reflection of the synthesized wave of the source RF signal at the on / off timing of the bias DC signal pulse P1. Furthermore, in the examples shown in Figures 17 to 24, even if the impedance changes relative to the synthesized waves of the first, second, and third source RF signals, impedance matching can be achieved using any one of the first, second, and third source RF signals. Therefore, even if the impedance changes relative to the synthesized wave at the time when, for example, the electrical pulse P1 of the bias DC signal is turned on, causing a change in the amount of reflection of the synthesized wave, the change can be suppressed at the appropriate time point.

[0119] Figure 25 is a timing diagram showing another example of this processing method. In the example shown in Figure 25, the electrical pulse P2 of the second source radio frequency signal is superimposed on the first source radio frequency signal and supplied to the substrate support 11 during the period Tb2 corresponding to the "period when the electrical pulse P1 of the bias DC signal is turned off". Furthermore, the electrical pulse P3 of the third source radio frequency signal is superimposed on the first source radio frequency signal and supplied to the substrate support 11 during the period Tc1 corresponding to the "period when the electrical pulse P1 of the bias DC signal is turned on".

[0120] In the example shown in Figure 25, the electrical pulse P2 of the second source RF signal can overlap with the first source RF signal at various time points shown in the examples in Figures 4 to 15. Furthermore, during the period Tb2 when the electrical pulse P2 of the second source RF signal is activated, electrical pulses of other RF signals can also overlap with the first source RF signal. The frequency or power of each RF signal including the second source RF signal can be arbitrarily set or adjusted according to its purpose.

[0121] In the example shown in Figure 25, the electrical pulse P3 of the third source RF signal can overlap with the first source RF signal at various time points shown in the examples in Figures 16 to 24. Furthermore, during the period Tc1 when the electrical pulse P3 of the third source RF signal is activated, electrical pulses of other RF signals can also overlap with the first source RF signal. The frequency or power of each RF signal including the third source RF signal can be arbitrarily set or adjusted according to its purpose.

[0122] Furthermore, the examples illustrated in the above figures can be appropriately combined and implemented. Moreover, in the examples illustrated in the figures, the number or frequency of each radio frequency signal superimposed on the first source radio frequency signal can be changed according to the plasma processing of this method. That is, the synthesized wave supplied to the substrate support 11 can also be changed according to the plasma processing of this method.

[0123] For example, when the etched film etched by this method is a multilayer film, the composite wave used for etching a specific layer within the multilayer film may differ from the composite wave used for etching another layer within the multilayer film. For instance, the substrate processing apparatus 1 may also have a configuration that identifies the type of film layer to be etched, and based on this identification, change the composite wave used for the etching process during the etching process. This allows for control of etching conditions according to the type of etched film, thereby improving the etch shape, etc. As an example, the configuration for identifying the type of film layer to be etched may be an optical emission spectrometer. Furthermore, as an example, the multilayer film may be a stacked film of silicon oxide and silicon nitride films.

[0124] Furthermore, for example, when etching a film with high aspect ratio holes using this processing method, the synthetic wave used in this processing method can be appropriately changed according to the progress of etching (depth or time, etc.). This allows for control of etching conditions according to the etching process, thereby improving the etched shape, etc. Furthermore, for example, the synthetic wave used in this processing method can be changed according to the progress of etching, thereby controlling the amount of byproducts such as polymers generated during the etching.

[0125] Furthermore, in the examples illustrated in the figures, the bias signal is not limited to a rectangular wave. The bias signal can be, for example, a trapezoidal wave, a triangular wave, a sawtooth wave, a sine wave, etc., as long as it can cause the voltage to change at a fixed period and apply a predetermined bias voltage to the upper electrode or the substrate support portion 11. Furthermore, the bias DC signal can also be one that pulses the radio frequency signal.

[0126] The above embodiments are described for illustrative purposes only and various modifications can be made without departing from the scope and spirit of the present invention. For example, in addition to using the capacitively coupled substrate processing apparatus 1, this processing method can also be performed using a substrate processing apparatus employing any plasma source such as inductively coupled plasma or microwave plasma. Furthermore, the present invention may include, for example, the following configuration.

[0127] (Postscript 1) A plasma processing method is a plasma processing method for performing plasma processing on a substrate in a plasma processing apparatus; The plasma treatment apparatus includes: Processing room; and A substrate support is provided in the processing chamber and configured to support the substrate; The plasma treatment method includes the following steps: The step of placing the substrate on the substrate support portion; The step of supplying processing gas to the processing chamber for processing the substrate; The steps of generating plasma of the processed gas in the processing chamber by means of a first radio frequency signal and a second radio frequency signal; and The step of supplying a bias signal to the substrate support portion; The plasma generation step includes superimposing the second radio frequency signal on the first radio frequency signal according to the timing of the bias signal being supplied to the substrate support.

[0128] (Postscript 2) As in Appendix 1, the plasma treatment method, in which, The bias signal is a pulse wave that periodically includes the first electrical pulse; The first radio frequency signal is a continuous wave of radio frequency with a first frequency; The second radio frequency signal is a pulse wave that periodically contains the second electrical pulse; The second electrical pulse is composed of a continuous radio frequency wave having a second frequency different from the first frequency.

[0129] (Note 3) As in the plasma processing method described in Appendix 2, the first electrical pulse is composed of one or more pulse voltages.

[0130] (Note 4) As in the plasma processing method in Appendix 2, the first electrical pulse is composed of a continuous radio frequency wave.

[0131] (Note 5) As shown in Appendix 2 regarding the plasma treatment method, in which, The period during which the first electrical pulse repeatedly appears in the bias signal, which is also the first period, is equal to the period during which the second electrical pulse repeatedly appears in the second radio frequency signal, which is also the second period.

[0132] (Note 6) As in any of the plasma treatment methods in Appendix 1 to 5, among which, In the plasma generation step, the first radio frequency signal and the second radio frequency signal are supplied to the substrate support.

[0133] (Note 7) As in the plasma processing method in Appendix 2, the time point at which the second electrical pulse occurs is the same as the time point at which the first electrical pulse stops.

[0134] (Postscript 8) As shown in Appendix 2 regarding the plasma treatment method, in which, The second electrical pulse occurred earlier than the first electrical pulse stopped.

[0135] (Note 9) As in the plasma processing method described in Appendix 2, the time point at which the second electrical pulse occurs is later than the time point at which the first electrical pulse stops.

[0136] (Postscript 10) As in any of the plasma processing methods in Appendix 7 to 9, the period during which the second electrical pulse stops in the second cycle is equal to the period during which the first electrical pulse occurs in the first cycle.

[0137] (Postscript 11) As in any of the plasma processing methods in Appendix 5 to 7, the period during which the second electrical pulse stops in the second cycle is longer than the period during which the first electrical pulse occurs in the first cycle.

[0138] (Postscript 12) As in any of the plasma processing methods in Appendix 7 to 9, the period during which the second electrical pulse stops in the second cycle is shorter than the period during which the first electrical pulse occurs in the first cycle.

[0139] (Postscript 13) As in the plasma treatment method in Appendix 6, the timing of the second electrical pulse is the same as the timing of the first electrical pulse.

[0140] (Postscript 14) As in the plasma processing method described in Appendix 6, the timing of the second electrical pulse is earlier than the timing of the first electrical pulse.

[0141] (Postscript 15) As in the plasma processing method described in Appendix 6, the timing of the second electrical pulse is later than the timing of the first electrical pulse.

[0142] (Postscript 16) As in any of the plasma processing methods in Appendix 13 to 15, the period during which the second electrical pulse occurs in the second cycle is equal to the period during which the first electrical pulse occurs in the first cycle.

[0143] (Postscript 17) As in any of Appendix 13 to 15, in a plasma processing method, the period during which the second electrical pulse occurs in the second cycle is longer than the period during which the first electrical pulse occurs in the first cycle.

[0144] (Postscript 18) As in any of the plasma treatment methods in Appendices 13 to 15, wherein, The second electrical pulse occurs during a shorter period in the second cycle than the first electrical pulse occurs during the first cycle.

[0145] (Postscript 19) As in any of the plasma treatment methods in Appendix 1 to 6, among which, The plasma generation step includes a step of further superimposing the third radio frequency signal on the first radio frequency signal according to the timing of the bias signal being supplied to the substrate support.

[0146] (Postscript 20) As shown in Appendix 19 regarding the plasma treatment method, in which, The third radio frequency signal is a pulse wave that periodically contains the third electrical pulse; The third electrical pulse is composed of a radio frequency having a third frequency different from the first frequency and the second frequency; The third electrical pulse overlaps at least in time with the second electrical pulse and with the first radio frequency signal.

[0147] (Postscript 21) As shown in Appendix 19 regarding the plasma treatment method, in which, The third radio frequency signal is a pulse wave that periodically contains the third electrical pulse; The third electrical pulse is composed of a radio frequency having a third frequency different from the first frequency and the second frequency; The third electrical pulse does not overlap with the second electrical pulse in time, but overlaps with the first radio frequency signal.

[0148] (Postscript 22) As in any of the plasma processing methods in Appendix 2 to 21, the second frequency is an integer multiple of the first frequency.

[0149] (Postscript 23) As in any of the plasma processing methods in Appendix 2 to 22, the pulse voltage includes a negative voltage.

[0150] (Postscript 24) A plasma treatment apparatus, comprising: Processing room; A substrate support portion is provided in the processing chamber and configured to support the substrate; and Control Department; This control unit performs the following controls; The substrate is disposed on the substrate support portion; Processing gas for processing the substrate is supplied to the processing chamber; Plasma of the processed gas is generated in the processing chamber by means of a first radio frequency signal and a second radio frequency signal; A bias signal is applied to the substrate support portion; Based on the timing at which the bias signal is applied to the substrate support portion, the second radio frequency signal is superimposed on the first radio frequency signal.

[0151] 1: Substrate processing device 10: Plasma treatment processing room 10a: Sidewall 10e: Gas exhaust outlet 10s: Plasma processing space 111: Main body 111a: Central Region 111b: Annular region 112: Ring assembly 113: Base 114: Electrostatic Chuck 115: Suction Cup Electrode 115a, 115b, 115c, 116a, 116b: Electrodes 116: Bias electrode 117: Electrode Plate 11:Substrate support department 13: Gas diffusion disk 13a: Gas supply port 13b: Gas diffusion chamber 13c: Gas inlet 15: Suction Cup Electrode 20: Gas Supply Department 21: Gas Source 22: Flow controller 30: Power supply 31: Radio Frequency Power Supply 31a: First Radio Frequency Generation Unit 31b: Second Radio Frequency Generation Unit 32: DC power supply 32a: First DC Generation Unit 32b: Second DC Generator Unit 40: Exhaust System 50: Control Department 50a1: Processing Department 50a2: Memory Department 50a3: Communication Interface 50a: Computer H1~H3, L1~L3: Electricity Levels P1, P2, P3: Electrical pulses P: Pulse voltage PDa, PDb, PDc: Period ST1~ST8: Steps Ta1, Ta2, Tb1, Tb2, Tc1, Tc2: Periods t1~t4: Time points V1, V2: Voltage VH, VL: Voltage levels W: substrate

Claims

1. A plasma treatment method, wherein a substrate is subjected to plasma treatment in a plasma treatment apparatus; The plasma processing apparatus includes: a processing chamber; and a substrate support disposed in the processing chamber for supporting the substrate; the plasma processing method includes the following steps: a step of placing the substrate in the substrate support; a step of supplying processing gas for processing the substrate to the processing chamber; a step of generating plasma of the processing gas in the processing chamber by means of a first source radio frequency signal and a second source radio frequency signal; and a step of supplying a bias signal to the substrate support; the step of generating plasma includes a step of superimposing the second source radio frequency signal on the first source radio frequency signal according to the timing of the bias signal being supplied to the substrate support.

2. The plasma treatment method as described in claim 1, wherein, The bias signal is a pulse wave that periodically includes a first electrical pulse; the first source radio frequency signal is a continuous radio frequency wave with a first frequency; the second source radio frequency signal is a pulse wave that periodically includes a second electrical pulse; the second electrical pulse is a continuous radio frequency wave with a second frequency different from the first frequency.

3. The plasma treatment method as described in claim 2, wherein, The first electrical pulse is composed of one or more pulse voltages.

4. The plasma treatment method as described in claim 2, wherein, The first electrical pulse is composed of a continuous wave of radio frequency.

5. The plasma treatment method as described in claim 2, wherein, The period during which the first electrical pulse repeatedly appears in the bias signal, also known as the first period, is equal to the period during which the second electrical pulse repeatedly appears in the second radio frequency signal, also known as the second period.

6. The plasma treatment method as described in claim 1, wherein, In the plasma generation step, the first source radio frequency signal and the second source radio frequency signal are supplied to the substrate support.

7. The plasma treatment method as described in claim 2, wherein, The second electrical pulse occurs at the same time as the first electrical pulse stops.

8. The plasma treatment method as described in claim 2, wherein, The second electrical pulse occurred earlier than the first electrical pulse stopped.

9. The plasma treatment method as described in claim 2, wherein, The second electrical pulse occurs later than the first electrical pulse stops.

10. The plasma treatment method as described in any of claims 7 to 9, wherein, The period during which the second electrical pulse stops in the second cycle is equal to the period during which the first electrical pulse occurs in the first cycle.

11. The plasma treatment method as described in claim 5, wherein, The period during which the second electrical pulse stops in the second cycle is longer than the period during which the first electrical pulse occurs in the first cycle.

12. The plasma treatment method as described in any of claims 7 to 9, wherein, The period during which the second electrical pulse stops in the second cycle is shorter than the period during which the first electrical pulse occurs in the first cycle.

13. The plasma treatment method as described in claim 2, wherein, The second electrical pulse occurs at the same time as the first electrical pulse.

14. The plasma treatment method as described in claim 2, wherein, The second electrical pulse occurred earlier than the first electrical pulse.

15. The plasma treatment method as described in claim 2, wherein, The second electrical pulse occurred later than the first electrical pulse.

16. The plasma treatment method as described in any of claims 13 to 15, wherein, The period during which the second electrical pulse occurs in the second cycle is equal to the period during which the first electrical pulse occurs in the first cycle.

17. The plasma treatment method as described in any of claims 13 to 15, wherein, The second electrical pulse occurs during a longer period in the second cycle than the first electrical pulse occurs during the first cycle.

18. The plasma treatment method as described in any of claims 13 to 15, wherein, The second electrical pulse occurs during a shorter period in the second cycle than the first electrical pulse occurs during the first cycle.

19. The plasma treatment method as described in any of claims 2 to 5, wherein, The plasma generation step includes a step of further superimposing the third source radio frequency signal on the first source radio frequency signal according to the timing of the bias signal being supplied to the substrate support.

20. The plasma treatment method as described in claim 19, wherein, The third source radio frequency signal is a pulse wave that periodically includes a third electrical pulse; the third electrical pulse is composed of a radio frequency wave having a third frequency that is different from the first frequency and the second frequency; at least a portion of the third electrical pulse overlaps with the second electrical pulse in time and overlaps with the first source radio frequency signal.

21. The plasma treatment method as described in claim 19, wherein, The third source radio frequency signal is a pulse wave that periodically includes a third electrical pulse; the third electrical pulse is composed of a radio frequency wave having a third frequency that is different from the first frequency and the second frequency; the third electrical pulse does not overlap with the second electrical pulse in time, but overlaps with the first source radio frequency signal.

22. The plasma treatment method as described in claim 2, wherein, The second frequency is an integer multiple of the first frequency.

23. The plasma treatment method as described in claim 3, wherein, This pulse voltage contains negative voltage.

24. A plasma treatment apparatus, comprising: Processing room; A substrate support section is provided in the processing chamber to support the substrate; and a control unit; this control unit performs the following controls; The substrate is placed on the substrate support; processing gas for processing the substrate is supplied to the processing chamber; The plasma of the processing gas is generated in the processing chamber by means of a first source radio frequency signal and a second source radio frequency signal; a bias signal is applied to the substrate support portion; and the second source radio frequency signal is superimposed on the first source radio frequency signal according to the time point at which the bias signal is applied to the substrate support portion.

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