Plasma processing method and plasma processing apparatus

Abstract

To provide a substrate processing technology having good in-plane uniformity.SOLUTION: A plasma processing method according to the present disclosure comprises the steps of: arranging a substrate on a substrate support part; supplying processing gas for processing the substrate into a chamber; supplying a first high frequency wave having a first frequency on an upper electrode or a bottom electrode to generate plasma of the processing gas between the upper electrode and the bottom electrode; and supplying a second high frequency wave having a second frequency being lower than the first frequency to the upper electrode or the bottom electrode, to control an electric field which is formed between the upper electrode or the bottom electrode and the plasma. And, the step of generating the plasma includes a step of controlling supply of the first high frequency wave on the basis of a phase of the second high frequency wave.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As a conventional technique, there is a plasma processing method described in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a plasma processing method with good in-plane uniformity.

Means for Solving the Problems

[0005] In one exemplary embodiment of the present disclosure, a plasma processing method for plasma-processing a substrate in a plasma processing apparatus, the plasma processing apparatus comprising: a chamber; a substrate support portion provided in the chamber, including a lower electrode and configured to support the substrate; and an upper electrode provided in the chamber opposite to the lower electrode, the substrate support portion being provided between the upper electrode and the lower electrode, the plasma processing method comprising: disposing a substrate on the substrate support portion; supplying a processing gas for processing the substrate into the chamber; supplying a first high-frequency wave having a first frequency to the upper electrode or the lower electrode to generate a plasma of the processing gas between the upper electrode and the lower electrode; and supplying a second high-frequency wave having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma, the step of generating the plasma including a step of controlling the supply of the first high-frequency wave based on the phase of the second high-frequency wave, a plasma processing method is provided.

[0006] In one exemplary embodiment of the present disclosure, there is provided a plasma processing apparatus for plasma-treating a substrate, comprising: a chamber; a substrate support portion provided in the chamber, including a lower electrode and configured to support the substrate; an upper electrode provided in the chamber opposite to the lower electrode, wherein the substrate support portion is provided between the upper electrode and the lower electrode; and a control unit. The control unit arranges a substrate on the substrate support portion, supplies a processing gas for processing the substrate into the chamber, supplies a first high-frequency wave having a first frequency to the upper electrode or the lower electrode to generate plasma of the processing gas between the upper electrode and the lower electrode, supplies a second high-frequency wave having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma, and executes control to control the supply of the first high-frequency wave based on the phase of the second high-frequency wave in the generation of the plasma.

Advantages of the Invention

[0007] According to one exemplary embodiment of the present disclosure, a plasma processing method with good in-plane uniformity can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0009] Hereinafter, each embodiment of the present disclosure will be described.

[0010] In one exemplary embodiment, a plasma processing method is provided.

[0011] The plasma processing method is a plasma processing method for plasma-processing a substrate in a plasma processing apparatus. The plasma processing apparatus includes a chamber, a substrate support portion provided in the chamber, the substrate support portion including a lower electrode and configured to support the substrate, and an upper electrode provided in the chamber opposite to the lower electrode, the substrate support portion being provided between the upper electrode and the lower electrode. The plasma processing method includes a step of disposing a substrate on the substrate support portion, a step of supplying a processing gas for processing the substrate into the chamber, a step of supplying a first high-frequency having a first frequency to the upper electrode or the lower electrode to generate a plasma of the processing gas between the upper electrode and the lower electrode, and a step of supplying a second high-frequency having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma. The step of generating plasma includes a step of controlling the supply of the first high-frequency based on the phase of the second high-frequency.

[0012] In one exemplary embodiment, the step of controlling the supply of the first high-frequency includes a step of supplying the first high-frequency to the upper electrode or the lower electrode at a first power to generate plasma, and a step of suppressing the generation of plasma by supplying the first high-frequency to the upper electrode or the lower electrode at a second power lower than the first power based on the phase of the second high-frequency.

[0013] In one exemplary embodiment, the step of suppressing plasma generation supplies the first high-frequency power to the upper electrode or the lower electrode at a second power when the phase of the second high-frequency is within one or more predetermined phase ranges.

[0014] In one exemplary embodiment, the one or more predetermined phase ranges are based on the sheath thickness at which the sheath formed between the upper electrode or the lower electrode and the plasma resonates with the chamber.

[0015] In one exemplary embodiment, the step of suppressing plasma generation supplies the first high-frequency power at a second power in two predetermined phase ranges.

[0016] In one exemplary embodiment, the plasma processing apparatus includes a control unit, and the plasma processing method further includes a step of storing one or more predetermined phase ranges in the control unit. The step of controlling the supply of the first high-frequency power controls the supply of the first high-frequency power based on the one or more predetermined phase ranges stored in the control unit.

[0017] In one exemplary embodiment, the method further includes a step of calculating the reactance of the chamber for the harmonics of the first high-frequency, and a step of calculating one or more predetermined phase ranges based on the calculated reactance. The step of controlling the supply of the first high-frequency power controls the supply of the first high-frequency power based on the calculated one or more predetermined phase ranges.

[0018] In one exemplary embodiment, a plasma processing apparatus for plasma-treating a substrate, comprising: a chamber; a substrate support provided in the chamber, including a lower electrode and configured to support the substrate; an upper electrode provided in the chamber opposite to the lower electrode, wherein the substrate support is provided between the upper electrode and the lower electrode; and a control unit. The control unit arranges the substrate on the substrate support, supplies a processing gas for processing the substrate into the chamber, supplies a first high-frequency wave having a first frequency to the upper electrode or the lower electrode to generate a plasma of the processing gas between the upper electrode and the lower electrode, supplies a second high-frequency wave having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma, and executes control to control the supply of the first high-frequency wave based on the phase of the second high-frequency wave in the generation of the plasma.

[0019] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or similar elements are denoted by the same reference numerals, and redundant descriptions are omitted. Unless otherwise specified, the positional relationships such as up, down, left, and right are described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0020] FIG. 1 is a diagram schematically showing a substrate processing apparatus 1 according to one exemplary embodiment. 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 source 30, an exhaust system 40, and a control unit 50. The substrate processing apparatus 1 also 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 showerhead 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support unit 11. In one exemplary embodiment, the showerhead 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 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 processing gas to the plasma processing space 10s and at least one gas discharge port for discharging gas from the plasma processing space. The sidewall 10a is grounded. The showerhead 13 and the substrate support unit 11 are electrically insulated from the plasma processing chamber 10 housing.

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

[0022] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the showerhead 13 includes a conductive member. The conductive member of the showerhead 13 functions as an upper electrode. Note that the gas introduction part may include, in addition to the showerhead 13, one or more side gas injectors (SGI) attached to one or a plurality of openings formed in the side wall 10a.

[0023] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one exemplary embodiment, the gas supply unit 20 is configured to supply at least one process gas from the corresponding gas source 21 to the showerhead 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include one or more flow modulation devices for modulating or pulsing the flow rate of at least one process gas.

[0024] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support 11 and / or the conductive member of the showerhead 13. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Further, by supplying a bias RF signal to the conductive member of the substrate support 11, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0025] 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 coupled to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13 via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one exemplary embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one exemplary embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13. The second RF generation unit 31b is coupled to the conductive member of the substrate support unit 11 via at least one impedance matching circuit, and is configured 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 has a frequency in the range of 400 kHz to 13.56 MHz. In one exemplary embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the conductive member of the substrate support unit 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed. Also, in one exemplary embodiment, the source signal and / or the bias RF signal may be applied to other electrodes such as the electrodes in the electrostatic chuck.

[0026] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one exemplary embodiment, the first DC generation unit 32a is connected to the conductive member of the substrate support 11 and configured 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 be applied to other electrodes such as the electrodes within the electrostatic chuck. In one exemplary embodiment, the second DC generation unit 32b is connected to the conductive member of the showerhead 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the showerhead 13. In various embodiments, at least one of the first and second DC signals may be pulsed. Note that the first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, and the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0027] The exhaust system 40 may be connected to, for example, a gas outlet 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0028] The control unit 50 processes computer-executable instructions that cause the substrate processing apparatus 1 to execute various processes described in the present disclosure. The control unit 50 may be configured to control each element of the substrate processing apparatus 1 to execute the various processes described herein. In one exemplary embodiment, part or all of the control unit 50 may be provided as part of the configuration of a device external to 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 storage unit 50a2, and a communication interface 50a3. The processing unit 50a1 may be configured to perform various control operations based on a program stored in the storage unit 50a2. The storage unit 50a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 50a3 may communicate with other components of the substrate processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0029] In addition to capacitively coupled plasma (CCP), the plasma formed in the plasma processing space may be inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Also, various types of plasma generation units including an alternating current (AC) plasma generation unit and a direct current (DC) plasma generation unit may be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit 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 RF signal has a frequency in the range of 200 kHz to 150 MHz.

[0030] FIG. 2 is a flowchart showing a substrate processing method (hereinafter also referred to as "the present processing method") according to one exemplary embodiment. The present processing method includes a step of calculating a predetermined phase range of a bias RF signal (ST1), a step of disposing a substrate W on a substrate support portion 11 (ST2), a step of supplying a processing gas into a plasma processing chamber 10 (ST3), a step of supplying a source RF signal to a lower electrode (ST4), a step of supplying a bias RF signal to the lower electrode (ST5), a step of determining whether to supply the source RF signal (ST6), a step of stopping the supply of the source RF signal and the bias RF signal (ST7), and a step of stopping the supply of the processing gas (ST8).

[0031] FIG. 3 is a flowchart showing an example of each step included in step ST1. Step ST1 includes a step of calculating the reactance of the plasma processing chamber (ST11), a step of calculating the sheath thickness (ST12), a step of calculating a predetermined phase range of the bias RF signal (ST13), and a step of storing the predetermined phase range (ST14).

[0032] This processing method is executed, for example, using the substrate processing apparatus 1. Each step of this processing method may be executed by the control unit 50 controlling each component of the substrate processing apparatus 1. Hereinafter, with reference to FIGS. 1 to 3, this processing method will be described.

[0033] In step ST1 (see FIG. 2), a predetermined phase range of the bias RF signal is stored. The predetermined phase range is stored, for example, in the storage unit 50a2 included in the control unit 50. The predetermined phase range may be stored, for example, at the time of factory shipment of the substrate processing apparatus 1 or during maintenance, etc., before this processing method is executed. Further, the predetermined phase range may be calculated and stored as one step of this processing method. Hereinafter, with reference to FIG. 3, an example of step ST1 will be described.

[0034] In step ST11, the reactance of the plasma processing chamber 10 is calculated. The reactance may be the reactance of the plasma processing chamber 10 with respect to the substrate W. Further, the reactance is the reactance corresponding to the peak value of the intensity of the Nth harmonic (N is an integer of 2 or more. Hereinafter also referred to as "harmonic") of the source RF signal or the reactance in the vicinity of the reactance. The peak value may be the maximum value of the intensity of the Nth harmonic.

[0035] The reactance of the plasma processing chamber 10 is calculated, for example, by the following steps. First, the impedance matching circuit included in the first RF generation unit 31a effectively changes the impedance of the plasma processing chamber 10. As a result, the reactance of the Nth harmonic of the source RF signal changes with the change in the impedance. Then, the intensity of the Nth harmonic at each reactance is measured. Then, the reactance corresponding to the peak value of the intensity of the Nth harmonic is calculated.

[0036] FIG. 4 is an example of a graph plotting the intensity of the N - th harmonic of the source RF signal against the reactance of the N - th harmonic. In the graph shown in FIG. 4, the horizontal axis represents the reactance (iΩ) of the plasma processing chamber 10 with respect to the substrate W. In step ST11, thus, based on the intensity of the N - th harmonic measured for each reactance, the reactance at which the intensity shows a peak value may be calculated.

[0037] Note that the reactance may be a single value or may be within a predetermined range. Also, the step ST1 of calculating the reactance may be executed prior to this processing method, for example, at the time of factory shipment or maintenance of the substrate processing apparatus 1. Further, the reactance may be measured after the plasma is generated in step ST4 of this processing method.

[0038] Hereinafter, with reference to FIG. 5, an example of step ST12 will be described.

[0039] FIG. 5 is a diagram showing the sheath S generated in the plasma processing chamber 10. When a source RF signal is supplied to the lower electrode (substrate support portion 11), plasma P is generated between the upper electrode (shower head 13) and the lower electrode. The sheath S is the space between the plasma P and the substrate W. In the present embodiment, based on the reactance of the plasma processing chamber 10, the thickness of the sheath S is calculated. In other embodiments, based on the reactance of the plasma processing chamber 10, the thickness of the sheath generated between the upper electrode and the plasma P may be calculated.

[0040] In step ST12 (see FIG. 3), based on the reactance calculated in step ST11, a predetermined sheath thickness d is calculated. The sheath thickness d may be calculated based on the thickness of the sheath S when the plasma processing chamber 10 resonates with the sheath S. The sheath thickness d is calculated, for example, based on the following formula (1).

[0041]

Equation

[0042] Here, X is the reactance of the plasma processing chamber 10, f HF is the frequency of the source RF signal, ε0 is the permittivity of free space, and M is the area of the substrate W.

[0043] Note that the sheath thickness d is not limited to the numerical value calculated based on the theoretical formula as shown in Equation (1). The sheath thickness d may be, for example, a numerical value obtained from an empirical rule such as experimental results, or may be a numerical value obtained based on both an empirical rule and theory. Further, the sheath thickness d may be a single value or may be within a predetermined range.

[0044] In step ST13 (see FIG. 3), based on the sheath thickness d calculated in step ST12, the phase range T of the bias RF signal is calculated. The phase range T may be calculated, for example, based on the following Equation (2).

[0045]

Equation

[0046] Here, ε0 is the permittivity of free space, V is the maximum voltage of the bias RF signal, e is the elementary charge, n is the electron density in the plasma P near the sheath S, f LF is the frequency of the bias RF signal, and t is the phase of the bias RF signal.

[0047] When the sheath thickness d calculated in step ST12 has a predetermined range, the phase range T of the bias RF signal may be calculated based on the range of the sheath thickness d. Further, when the sheath thickness d is a single value, the phase range T of the bias RF signal may calculate a predetermined phase t based on the sheath thickness d and calculate the phase range T based on the phase t. Further, two or more phase ranges T may be calculated for one cycle of the bias RF signal. In this case, the sheath thickness d corresponding to each of the two or more phase ranges T may be the same thickness.

[0048] In step ST14 (see FIG. 3), the phase range T calculated in step ST14 is stored. The phase range T may be stored in the storage unit 50a2 included in the control unit 50. Note that the phase range T stored in step ST14 may be a phase range obtained without executing some or all of steps ST11 to ST14. The phase range T may be, for example, a phase range obtained based only on empirical rules. Further, the phase range T may be calculated, for example, based on the reactance calculated in step ST11 among steps ST11 to ST14.

[0049] In step ST2 (see FIG. 2), the substrate W is placed on the substrate support 11. The substrate W may be, for example, a substrate on which an underlayer film, an etching target film, a mask film having a predetermined pattern, etc. are laminated on a silicon wafer. The etching target film is a film to be etched by this processing method. Further, the etching target film may be, for example, a dielectric film, a semiconductor film, a metal film, or the like.

[0050] In step ST3, a processing gas is supplied into the plasma processing chamber 10. The processing gas is a gas used to etch the etching target film formed on the substrate W. The type of the processing gas may be appropriately selected based on the material of the etching target film, the material of the mask film, the material of the underlayer film, the pattern of the mask film, the etching depth, etc.

[0051] In step ST4, a source RF signal is supplied to the lower electrode included in the main body 111 of the substrate support 11. The source RF signal is an example of a first high frequency. When the source RF signal is supplied to the lower electrode, plasma is formed from the processing gas supplied into the plasma processing chamber 10. The frequency of the source RF signal is, for example, from 13 MHz to 150 MHz. Further, in other embodiments, the source RF signal may be supplied to the upper electrode included in the shower head 13.

[0052] In step ST5, a bias RF signal is supplied to the lower electrode included in the main body 111 of the substrate support 11. The bias RF signal is an example of a second high frequency. When the bias RF signal is supplied to the lower electrode, the electric field formed between the lower electrode and the plasma P by the bias RF signal is controlled. Thereby, the ion components present in the plasma P and the sheath S (see FIG. 5) and drawn into the substrate W are controlled. The frequency of the bias RF signal is, for example, from 400 KHz to 13.56 MHz. In other embodiments, the bias RF signal may be supplied to the upper electrode included in the shower head 13.

[0053] When steps ST4 and ST5 are started, an etching process is started on the substrate W by the ion components generated in the plasma P. Note that steps ST4 and ST5 may be started simultaneously. Also, step ST5 may be started prior to step ST4. That is, the bias RF signal may be supplied to the lower electrode prior to the source RF signal.

[0054] In step ST6, it is determined whether to continue or stop the supply of the source RF signal. Step ST6 includes a step (ST61) of determining whether the phase of the bias RF signal is within a predetermined phase range T, a step (ST62) of continuing the supply of the source RF signal, a step (ST63) of stopping the sharing of the source RF signal, and a step (ST64) of determining whether to end the etching process. Hereinafter, the processing in step ST6 will be described with reference to FIG. 6.

[0055] FIG. 6 is a timing chart schematically showing an example of changes in the source RF signal, the bias RF signal, and the sheath thickness in this processing method. FIG. 6 shows the processing for two cycles of the bias RF signal among the processing continuously performed in step ST6 in this processing method. In FIG. 6, the horizontal axis indicates the phase of the bias RF signal (the supply time of the bias RF signal). The vertical axis indicates the power of the source RF signal, the power of the bias RF signal, and the thickness of the sheath S. As shown in FIG. 6, the phase of the bias RF signal may be shifted by 180 degrees from the phase of the sheath thickness d.

[0056] In the example shown in FIG. 6, the phase range T is from angle θ1 to angle θ2 (from angle θ5 to angle θ6) and from angle θ3 to angle θ4 (from angle θ7 to angle θ8). That is, in the example shown in FIG. 6, two phase ranges T are stored in the storage unit 50a2 for one cycle. Also, the range D of the sheath thickness corresponding to the two phase ranges T is both from thickness d1 to thickness d2.

[0057] In step ST61, it is determined whether the phase of the bias RF signal is within the phase range T. First, the phase range T stored in the storage unit 50a2 is called. Then, when the current phase t of the bias RF signal is not within the range of the phase range T (ST61 No), in step ST62, the supply of the source RF signal is continued. Examples where the current phase t of the bias RF signal is not within the range of the phase range T are when the phase t is in the range of 0 or more and less than angle θ1 or when it is from angle θ2 to angle θ3.

[0058] On the other hand, when the current phase t of the bias RF signal is within the range of the phase range T (step ST61 Yes), in step ST63, the supply of the source RF signal is stopped. When the current phase t of the bias RF signal is within the range of the phase range T, for example, it is when the phase t reaches angle θ1. Also, when the current phase t of the bias RF signal is within the range of the phase range T, the supply of the source RF signal may be restricted, for example, by reducing the power or voltage of the source RF signal compared to when the current phase t of the bias RF signal is not within the range of the phase range T.

[0059] In step ST62 or step ST63, after the supply of the source RF signal is continued or stopped, in step ST64, it is determined whether to end the etching process. If it is determined to continue the etching process (ST64 No), the supply or stop of the source RF signal is continued, and the process returns to step ST61 and the process continues.

[0060] In step ST6, by repeating the above operations, the supply of the source RF signal is controlled according to the phase t of the bias RF signal. That is, when the phase t of the bias RF signal is not within the phase range T, both the source RF signal and the bias RF signal are supplied to the lower electrode. On the other hand, when the phase t of the bias RF signal is within the phase range T, the supply of the source RF signal is stopped, and only the bias RF signal is supplied to the lower electrode.

[0061] Then, in step ST64, when it is determined that the etching process is completed (ST64 Yes), in step ST7, the supply of the source RF signal and the bias RF signal is stopped. Also, in step ST8, the supply of the processing gas is stopped, and this processing method ends.

[0062] According to one exemplary embodiment of the present disclosure, the source RF signal and the bias RF signal are supplied to the lower electrode (or upper electrode) at a sheath thickness or a phase of the bias RF signal at which the plasma processing chamber 10 and the sheath S do not resonate. For example, at a sheath thickness or a phase of the bias RF signal at which the plasma processing chamber 10 and the sheath S resonate, the supply of the source RF signal is restricted or stopped. In this way, by controlling the supply of the source RF signal, the excitation of the harmonics of the source RF signal can be suppressed. As a result, a substrate processing method with good in-plane uniformity of the etching rate can be provided.

[0063] The above embodiments are described for the purpose of explanation and can be variously modified without departing from the scope and spirit of the present disclosure. For example, this processing method can be executed using a substrate processing apparatus using an arbitrary plasma source such as an inductively coupled plasma or a microwave plasma, in addition to the capacitively coupled substrate processing apparatus 1.

Description of Reference Numerals

[0064] 1… Substrate processing apparatus, 10… Plasma processing chamber, 11… Substrate support part, 13… Shower head, 20… Gas supply part, 22… Flow controller, 30… Power supply, 31… RF power supply, 32… DC power supply, 40… Exhaust system, 50… Control part, 111… Main body part, 112… Ring assembly, d… Sheath thickness, P… Plasma, S… Sheath, T… Phase range, W… Substrate

Claims

1. A plasma processing method for plasma-processing a substrate in a plasma processing apparatus, comprising: the plasma processing apparatus comprising: a chamber; a substrate support provided in the chamber, including a lower electrode and configured to support the substrate; an upper electrode provided in the chamber opposite to the lower electrode, the substrate support being provided between the upper electrode and the lower electrode; and the plasma processing method comprising: placing a substrate on the substrate support; supplying a processing gas for processing the substrate into the chamber; supplying a first high-frequency wave having a first frequency to the upper electrode or the lower electrode to generate a plasma of the processing gas between the upper electrode and the lower electrode; supplying a second high-frequency wave having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma; wherein the step of generating the plasma includes a step of controlling the supply of the first high-frequency wave based on the phase of the second high-frequency wave; the step of controlling the supply of the first high-frequency wave includes: supplying the first high-frequency wave to the upper electrode or the lower electrode at a first power to generate plasma; supplying the first high-frequency wave to the upper electrode or the lower electrode at a second power lower than the first power based on the phase of the second high-frequency wave to suppress the generation of the plasma; wherein the step of suppressing the generation of the plasma includes supplying the first high-frequency wave to the upper electrode or the lower electrode at the second power when the phase of the second high-frequency wave is within one or more predetermined phase ranges; the one or more predetermined phase ranges are based on the thickness of a sheath formed between the upper electrode or the lower electrode and the plasma and resonating with the chamber, a plasma processing method.

2. A plasma processing method for plasma-processing a substrate in a plasma processing apparatus, comprising: the plasma processing apparatus comprising: a chamber; a substrate support provided in the chamber, including a lower electrode and configured to support the substrate; an upper electrode provided in the chamber opposite to the lower electrode, the substrate support being provided between the upper electrode and the lower electrode; comprising, the plasma processing method comprising: a step of disposing a substrate on the substrate support portion; a step of supplying a processing gas for processing the substrate into the chamber; a step of supplying a first high-frequency wave having a first frequency to the upper electrode or the lower electrode to generate plasma of the processing gas between the upper electrode and the lower electrode; a step of supplying a second high-frequency wave having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma and including: the step of generating the plasma includes a step of controlling the supply of the first high-frequency wave based on the phase of the second high-frequency wave; the step of controlling the supply of the first high-frequency wave includes: a step of supplying the first high-frequency wave to the upper electrode or the lower electrode at a first power to generate plasma; a step of suppressing the generation of the plasma by supplying the first high-frequency wave to the upper electrode or the lower electrode at a second power lower than the first power based on the phase of the second high-frequency wave and including: the step of suppressing the generation of the plasma includes supplying the first high-frequency wave to the upper electrode or the lower electrode at the second power when the phase of the second high-frequency wave is within one or more predetermined phase ranges, a step of calculating a reactance of the chamber with respect to a harmonic of the first high-frequency wave; a step of calculating the one or more predetermined phase ranges based on the calculated reactance and further including: the step of controlling the supply of the first high-frequency wave controls the supply of the first high-frequency wave based on the calculated one or more predetermined phase ranges, a plasma processing method.

3. The step of suppressing the generation of the plasma supplies the first high-frequency wave at the second power in the two predetermined phase ranges, the plasma processing method according to claim 1 or 2.

4. The plasma processing apparatus has a control unit, the plasma processing method further includes a step of storing the one or more predetermined phase ranges in the control unit, the step of controlling the supply of the first high-frequency wave controls the supply of the first high-frequency wave based on the one or more predetermined phase ranges stored in the control unit, the plasma processing method according to claim 1 or 2.

5. A plasma processing apparatus for plasma-processing a substrate, comprising: a chamber; A substrate support portion provided in the chamber, including a lower electrode and configured to support the substrate, the substrate support portion; An upper electrode provided in the chamber opposite to the lower electrode, wherein the substrate support portion is provided between the upper electrode and the lower electrode, the upper electrode; A control unit And the control unit Places a substrate on the substrate support portion; Supplies a processing gas for processing the substrate into the chamber; Supplies a first high-frequency wave having a first frequency to the upper electrode or the lower electrode to generate plasma of the processing gas between the upper electrode and the lower electrode; Supplies a second high-frequency wave having a second frequency lower than the first frequency to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma; In the generation of the plasma, controls the supply of the first high-frequency wave based on the phase of the second high-frequency wave; The control of the supply of the first high-frequency wave Includes controlling to supply the first high-frequency wave to the upper electrode or the lower electrode with a first power to generate plasma; And controlling to supply the first high-frequency wave to the upper electrode or the lower electrode with a second power lower than the first power based on the phase of the second high-frequency wave to suppress the generation of the plasma And includes; The control for suppressing the generation of the plasma supplies the first high-frequency wave to the upper electrode or the lower electrode with the second power when the phase of the second high-frequency wave is within one or more predetermined phase ranges; The one or more predetermined phase ranges are based on the thickness of a sheath formed between the upper electrode or the lower electrode and the plasma that resonates with the chamber; A plasma processing apparatus that executes the control.

6. A plasma processing apparatus for plasma-processing a substrate, comprising: A chamber; A substrate support portion provided in the chamber, including a lower electrode and configured to support the substrate, the substrate support portion; An upper electrode provided in the chamber opposite to the lower electrode, wherein the substrate support portion is provided between the upper electrode and the lower electrode, the upper electrode; A control unit And the control unit Places a substrate on the substrate support portion; Supplies a processing gas for processing the substrate into the chamber; A first high-frequency wave having a first frequency is supplied to the upper electrode or the lower electrode to generate plasma of the processing gas between the upper electrode and the lower electrode. A second high-frequency wave having a second frequency lower than the first frequency is supplied to the upper electrode or the lower electrode to control an electric field formed between the upper electrode or the lower electrode and the plasma. In the generation of the plasma, the supply of the first high-frequency wave is controlled based on the phase of the second high-frequency wave. The control of the supply of the first high-frequency wave includes control of supplying the first high-frequency wave to the upper electrode or the lower electrode at a first power to generate plasma, and a step of suppressing the generation of the plasma by supplying the first high-frequency wave to the upper electrode or the lower electrode at a second power lower than the first power based on the phase of the second high-frequency wave. The control for suppressing the generation of the plasma includes supplying the first high-frequency wave to the upper electrode or the lower electrode at the second power when the phase of the second high-frequency wave is within one or more predetermined phase ranges. The control further includes control for calculating the reactance of the chamber with respect to the harmonics of the first high-frequency wave, and control for calculating the one or more predetermined phase ranges based on the calculated reactance. Based on the calculated one or more predetermined phase ranges, the supply of the first high-frequency wave is controlled. A plasma processing apparatus that executes the control. ​

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