Plasma processing apparatus

Abstract

A plasma processing apparatus disclosed includes a chamber, a substrate support section, a high-frequency power supply, and a bias power supply control section. The high-frequency power supply generates a generation-source high-frequency power to generate plasma in the chamber. The bias power supply periodically applies a bias energy having a waveform period to a bias electrode of the substrate support section. The high-frequency power supply adjusts a generation-source frequency of the generation-source high-frequency power during an nth phase period in an mth waveform period of a plurality of waveform periods, according to a change in a degree of reflection of the generation-source high-frequency power. The change in the degree of reflection is determined by using different generation-source frequencies from each other during the nth phase period in each of two or more periods before the mth waveform period.

Description

[0001] This case is a divisional application of the application filed on January 21, 2022, with application number 202280010797.6, entitled "Plasma Processing Apparatus and Method for Controlling the Frequency of a Generating Source by Controlling the High-Frequency Power of a Generating Source". Technical Field

[0002] The exemplary embodiments of the present invention relate to plasma processing apparatus. Background Technology

[0003] Plasma processing apparatuses are used in the plasma processing of substrates. To introduce ions from the plasma generated within a chamber into the substrate, the plasma processing apparatus uses a bias high-frequency power. Patent Document 1 below discloses a plasma processing apparatus that modulates the power level and frequency of the bias high-frequency power.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-246091 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] This invention provides a technique for reducing the reflection of high-frequency power from a plasma generation source in a plasma processing apparatus.

[0009] Technical solutions for solving technical problems

[0010] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a high-frequency power supply, and a bias power supply. The substrate support has bias electrodes disposed within the chamber. The high-frequency power supply is configured to generate high-frequency power from a generation source to generate plasma within the chamber. The bias power supply is configured to periodically apply bias energy having a waveform period to the bias electrodes. The high-frequency power supply is configured to set the generation source frequency of the high-frequency power from the generation source in each phase period of each of the multiple phase periods of the multiple waveform periods of the bias energy. The high-frequency power supply is configured to provide feedback such that the generation source frequency in the nth phase period of the m-th waveform period is adjusted based on a change in the degree of reflection of the high-frequency power from the generation source. The change in the degree of reflection is determined by using different generation source frequencies in the nth phase periods of each of two or more waveform periods preceding the m-th waveform period.

[0011] Invention Effects

[0012] According to one exemplary embodiment, the degree of reflection of the high-frequency power of the generation source can be reduced in a plasma processing apparatus. Attached Figure Description

[0013] Figure 1 This is a diagram that schematically illustrates a plasma processing apparatus of an exemplary embodiment.

[0014] Figure 2 This is a diagram that schematically illustrates a plasma processing apparatus of an exemplary embodiment.

[0015] Figure 3 This is a timing diagram of an example of bias energy and the generator source frequency of the high-frequency power of the generator source.

[0016] Figure 4 This is a timing diagram of another example of a generator frequency with bias energy and high generator power.

[0017] Figure 5 This is a timing diagram for another example of bias energy.

[0018] Figure 6 This is a flowchart illustrating an exemplary implementation of a method for controlling the generator source frequency of the high-frequency power of a generator source.

[0019] Figure 7 This is another example of a timing diagram showing the bias energy and the generator source frequency of the high-frequency power of the generator source.

[0020] Figure 8 This is a flowchart illustrating an exemplary implementation of a method for determining the generator source frequency of the high-frequency power of a generator source.

[0021] Figure 9 This is another example of a timing diagram showing the bias energy and the generator source frequency of the high-frequency power of the generator source.

[0022] Figure 10 This is another example of a timing diagram showing the bias energy and the generator source frequency of the high-frequency power of the generator source.

[0023] Figure 11 This is a diagram representing an example of the power spectrum of the high-frequency power of the generating source.

[0024] Figure 12 This is a flowchart illustrating a method for determining the generation source frequency of the generation source high-frequency power in another exemplary embodiment.

[0025] Figure 13 This is a diagram illustrating an example of the structure of a matcher.

[0026] Figure 14 This is a flowchart illustrating a method for determining optimal settings in an exemplary embodiment. Detailed Implementation

[0027] The following describes various illustrative implementation methods.

[0028] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a high-frequency power supply, and a bias power supply. The substrate support has bias electrodes disposed within the chamber. The high-frequency power supply is configured to generate high-frequency power to generate plasma within the chamber. The bias power supply is configured to periodically apply bias energy having a waveform period to the bias electrodes. The high-frequency power supply is configured to set the generation source frequency of the high-frequency power in each phase period of each of the multiple waveform periods of the bias energy. The high-frequency power supply is configured to provide feedback such that, based on changes in the degree of reflection of the high-frequency power, the generation source frequency f(m, n) in the nth phase period of the m-th waveform period is adjusted. f(m, n) is the generation source frequency in the nth phase period of the m-th waveform period. The change in the degree of reflection is determined by using different generation source frequencies in the nth phase periods of each of two or more waveform periods preceding the m-th waveform period.

[0029] By using different generator source frequencies during the nth phase of each of two or more waveform periods, the relationship between the change (frequency shift) of the generator source frequency and the change in the degree of reflection can be determined. Therefore, according to the above embodiment, the generator source frequency used during the nth phase of the mth waveform period can be adjusted to reduce the degree of reflection based on the change in the degree of reflection of the high-frequency power of the generator source. In addition, according to the above embodiment, the degree of reflection can be reduced rapidly in each of the multiple waveform periods in which bias energy is applied to the bias electrode of the substrate support.

[0030] In one exemplary implementation, the two or more waveform periods may also comprise (m-M1) waveform periods and (m-M2) waveform periods. Here, M1 and M2 are natural numbers that satisfy M1 > M2.

[0031] In one exemplary embodiment, the feedback may also include the operation of applying a frequency shift to the source frequency f(m-M2,n), either down-shifting or up-shifting from the source frequency f(m-M1,n). This can result in a reduction in the degree of reflection due to the frequency shift. In this case, the feedback may also set f(m,n) to a frequency with a frequency shift relative to f(m-M2,n). Alternatively, if the power level of reflection increases when using f(m,n) obtained with a frequency shift, the feedback may set the source frequency f(m+M3,n) to an intermediate frequency. The intermediate frequency is the frequency between f(m-M2,n) and f(m,n), where M3 is a natural number.

[0032] In one exemplary embodiment, it is possible that the degree of reflection when using the aforementioned intermediate frequency during the nth phase period within the (m+M3)th waveform period is greater than a threshold. In this case, the feedback may also set the generation source frequency f(m+M4,n) to a frequency with a different frequency shift relative to the intermediate frequency. The absolute value of the other frequency shift is greater than the absolute value of the aforementioned frequency shift. Here, M4 is a natural number satisfying M4 > M3.

[0033] In one exemplary implementation, the absolute value of a frequency shift used to obtain the source frequency f(m, n) may be greater than the absolute value of a frequency shift used to obtain the source frequency f(m-M2, n).

[0034] In one exemplary embodiment, the feedback may also include the step of applying a frequency shift to the generated source frequency f(m-M2,n), either down-shifting or up-shifting from the generated source frequency f(m-M1,n). This may result in an increased degree of reflection due to one of the frequency shifts. In this case, the feedback may also set f(m,n) to a frequency with a different frequency shift relative to f(m-M2,n).

[0035] In one exemplary embodiment, the bias energy may also be a bias high-frequency power having a bias frequency, wherein the bias frequency is the reciprocal of the time length of the waveform period. Alternatively, the bias energy may consist of pulses of voltage applied to the bias electrode in each of a plurality of waveform periods, each having a time length that is the reciprocal of the bias frequency.

[0036] In one exemplary embodiment, the high-frequency power supply may use multiple frequencies included in a pre-prepared initial frequency set during multiple phase periods within the initial waveform period of multiple waveform cycles.

[0037] In one exemplary embodiment, the plasma processing apparatus may also include a control unit.

[0038] In one exemplary embodiment, the control unit may set the generation source frequencies used in the same phase period of multiple reference periods, each of which is a period of the aforementioned waveform, to multiple different frequencies. Alternatively, the control unit may determine multiple appropriate frequencies for each phase period of the multiple phase periods by selecting an appropriate frequency from among these frequencies that minimizes the degree of reflection in each phase period of the multiple phase periods. Alternatively, the control unit may store these multiple appropriate frequencies as multiple frequencies in the storage unit of the plasma processing apparatus as a set of initial frequencies.

[0039] In one exemplary embodiment, the control unit may cause a high-frequency power source to generate high-frequency power having multiple frequency components to generate plasma in the chamber during a reference period, which is the period of the aforementioned waveform. Alternatively, the control unit may calculate multiple ratios and determine the smallest of these ratios, where the multiple ratios are ratios of the power levels of reflected waves of multiple frequency components in each of the multiple phase periods within the reference period to the power levels of traveling waves of the multiple frequency components. Alternatively, the control unit may determine multiple appropriate frequencies for each phase period of the multiple phase periods by determining the frequency of the frequency component that results in the smallest ratio among the multiple frequency components in each phase period of the multiple phase periods. Alternatively, the control unit may store the multiple appropriate frequencies as multiple frequencies of an initial frequency group in the storage unit of the plasma processing apparatus.

[0040] In one exemplary embodiment, the plasma processing apparatus may also include a matching device. The matching device includes a first variable capacitor and a second variable capacitor. The first variable capacitor is connected between a node in a power supply path that connects the high-frequency power source and the high-frequency electrodes supplied with the high-frequency power to the generation source and ground. The second variable capacitor is connected between the node and the high-frequency electrodes. Alternatively, the matching device may use a pre-prepared optimal matching device setting from a plurality of optimal matching device settings for the first and second variable capacitors, corresponding to the processing performed in the plasma processing apparatus, during the initial waveform period of a plurality of waveform cycles. Alternatively, the high-frequency power source may use a plurality of frequencies from a pre-prepared plurality of initial frequency groups, corresponding to the processing performed in the plasma processing apparatus, during multiple phase periods within the initial waveform period.

[0041] In one exemplary embodiment, the control unit may sequentially use multiple matching settings of the first and second variable capacitors under the conditions described above, and generate multiple provisional settings. To generate multiple provisional settings, the control unit may, under each matching setting of the multiple matching settings, set the generation source frequencies used in the same phase period of multiple reference periods, each of which is a waveform period, to multiple frequencies that are different from each other, or select the provisional frequency that minimizes the degree of reflection in each phase period of the multiple phase periods among these multiple frequencies. Thus, the control unit may generate multiple provisional settings, each of which includes a provisional frequency group and a corresponding matching setting among the multiple matching settings, wherein the provisional frequency group includes multiple provisional frequencies for each phase period of the multiple phase periods. Alternatively, the control unit may determine the provisional setting that minimizes the degree of reflection among the multiple provisional settings. Alternatively, the control unit may store the matching settings and provisional frequency groups included in the determined provisional settings in the storage unit of the plasma processing apparatus as the optimal matching setting and initial frequency group corresponding to the above-described process.

[0042] In one exemplary embodiment, the control unit may sequentially use multiple matching settings of the first and second variable capacitors under the conditions described above, and generate multiple provisional settings. To generate multiple provisional settings, the control unit may: (a) generate high-frequency power with multiple frequency components from the high-frequency power supply under each matching setting of the multiple matching settings, to generate plasma in the chamber during a reference period, which is the waveform period; (b) calculate multiple ratios and determine the smallest ratio among them, where the multiple ratios are ratios of the power levels of reflected waves of multiple frequency components in each of the multiple phase periods within the reference period to the power levels of traveling waves of multiple frequency components; and (c) determine multiple provisional frequencies for each phase period of the multiple phase periods by determining the frequency of the frequency component that results in the smallest ratio among the multiple frequency components in each phase period of the multiple phase periods. Thus, the control unit may generate multiple provisional settings, each of which includes a provisional frequency group and a corresponding matching setting among the multiple matching settings, wherein the provisional frequency group includes multiple provisional frequencies for each phase period of the multiple phase periods. Alternatively, the control unit may determine the provisional setting that minimizes the degree of reflection from among multiple provisional settings. Alternatively, the control unit may store the matched set and provisional frequency group included in the determined provisional setting as the optimal matched set and initial frequency group corresponding to the above-described process in the storage unit of the plasma processing apparatus.

[0043] In another exemplary embodiment, a method is provided for controlling the generation source frequency of the high-frequency power of the generation source. The method includes step (a) applying bias energy to a bias electrode of a substrate support disposed within a cavity of a plasma processing apparatus. The bias energy has a waveform period and is periodically applied to the bias electrode. The method further includes step (b) supplying high-frequency power from a high-frequency power source to generate plasma within the cavity. The method further includes step (c) setting the generation source frequency of the high-frequency power of the generation source during each phase period of a plurality of phase periods of a plurality of waveform periods. The generation source frequency f(m, n) is adjusted according to a change in the degree of reflection of the high-frequency power of the generation source. The change in the degree of reflection is determined by using different generation source frequencies during the nth phase period of each of two or more periods preceding the m-th waveform period.

[0044] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. Furthermore, in each drawing, the same or corresponding parts are labeled with the same reference numerals.

[0045] Figure 1 and Figure 2 This is a diagram that schematically illustrates a plasma processing apparatus of an exemplary embodiment.

[0046] In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to the gas supply unit 20 (described later), and the gas outlet is connected to the exhaust system 40 (described later). The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0047] The plasma generation unit 12 is configured to generate plasma from at least one process gas supplied to the plasma processing space. The plasma generated in the plasma processing space can be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), ECR plasma (Electron-Cyclotron-resonance plasma), Helicon Wave Plasma (HWP), or surface wave plasma (SWP), etc. Furthermore, various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC (Direct Current) plasma generation units, can also be used.

[0048] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various steps described herein. The control unit 2 is configured to control the various elements of the plasma processing apparatus 1 to enable the execution of the various steps described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may, for example, include a computer 2a. The computer 2a may, for example, include a processing unit (CPU) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control actions based on a program stored in the storage unit 2a2. The storage unit 2a2 may also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface 2a3 may also communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0049] The following describes a configuration example of a capacitively coupled plasma processing apparatus 1, which is an example of a plasma processing apparatus 1. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a spray head 13. The substrate support 11 is disposed within the plasma processing chamber 10. The spray head 13 is disposed above the substrate support 11. In one embodiment, the spray head 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 spray head 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The sidewall 10a is grounded. The spray head 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0050] 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 when viewed from above. 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 in such a way that it surrounds the substrate W on the central region 111a of the main body portion 111. In one embodiment, the main body portion 111 includes a base 111e and an electrostatic chuck 111c. The base 111e includes conductive components. The conductive components of the base 111e function as a lower electrode. The electrostatic chuck 111c is disposed on the base 111e. The upper surface of the electrostatic chuck 111c has a substrate support surface 111a. The ring assembly 112 includes one or more annular components. At least one of the annular components is an edge ring. Additionally, although not shown in the figures, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 111c, the ring assembly 112, and the substrate W to a target temperature. The temperature control module may also include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path. Furthermore, the substrate support 11 may also include a heat transfer gas supply section configured to supply heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0051] The spray head 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The spray head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlets 13c. The process gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the plurality of gas inlets 13c. Additionally, the spray head 13 includes a conductive component. The conductive component of the spray head 13 functions as an upper electrode. Furthermore, in addition to the spray head 13, the gas inlet may also include one or more side gas injectors (SGIs) installed in one or more openings formed in the sidewall 10a.

[0052] The gas supply unit 20 may also include one or more gas sources 21 and at least one or more flow controllers 22. In one embodiment, the gas supply unit 20 is configured to supply one or more processing gases from their respective gas sources 21 to the spray head 13 via their respective flow controllers 22. Each flow controller 22 may, for example, include a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include one or more flow modulation devices that modulate or pulse the flow rate of the one or more processing gases.

[0053] The exhaust system 40 can be connected, for example, to a gas outlet 10e 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 regulating valve can be used to regulate the pressure within the plasma processing space 10s. The vacuum pump may also include a turbomolecular pump, a dry pump, or a combination thereof.

[0054] The plasma processing apparatus 1 also includes a high-frequency power supply 31 and a bias power supply 32. The plasma processing apparatus 1 may also include a sensor 31s and a control unit 30c.

[0055] The high-frequency power supply 31 generates a high-frequency power RF to generate plasma within the chamber (plasma processing chamber 10). The high-frequency power RF has a generation source frequency, for example, between 13 MHz and 150 MHz. In one embodiment, the high-frequency power supply 31 may also include a high-frequency signal generator 31g and an amplifier 31a. The high-frequency signal generator 31g generates a high-frequency signal. The amplifier 31a generates the high-frequency power RF by amplifying the high-frequency signal input from the high-frequency signal generator 31g and outputs the high-frequency power RF. Furthermore, the high-frequency signal generator 31g may also be constructed from a programmable processor or a programmable logic device such as an FPGA. Additionally, a D / A converter may be connected between the high-frequency signal generator 31g and the amplifier 31a.

[0056] The high-frequency power supply 31 is connected to the high-frequency electrode via a matching adapter 31m. In one embodiment, the base 111e constitutes the high-frequency electrode. In another embodiment, the high-frequency electrode may also be an electrode disposed in the electrostatic chuck 111c. The high-frequency electrode may also be a common electrode with the bias electrode described later. Alternatively, the high-frequency electrode may also be an upper electrode. The matching adapter 31m includes a matching circuit. The matching circuit of the matching adapter 31m has a variable impedance. The matching circuit of the matching adapter 31m is controlled by the control unit 30c. The impedance of the matching circuit of the matching adapter 31m is adjusted to match the impedance on the load side of the high-frequency power supply 31 with the output impedance of the high-frequency power supply 31.

[0057] Sensor 31s is configured to output a reflected wave of the high-frequency power RF returned from the load of the high-frequency power supply 31 to the control unit 30c. Sensor 31s can also be connected between the high-frequency power supply 31 and the matching unit 31m. Sensor 31s can also be connected between the matching unit 31m and the high-frequency electrode. For example, sensor 31s can be connected between the junction of an electrical path extending from the matching unit 31m toward the bias electrode and an electrical path extending from the matching unit 32m (described later) toward the bias electrode, and the bias electrode. Alternatively, sensor 31s can be connected between this junction and the matching unit 31m. Sensor 31s includes, for example, a directional coupler. The directional coupler outputs the reflected wave returned from the load of the high-frequency power supply 31. The reflected wave output from the directional coupler is converted into a digital signal by an A / D converter, and the digitized reflected wave is utilized in the control unit 30c. Furthermore, sensor 31s can be a sensor separate from the matching unit 31m, or it can be part of the matching unit 31m.

[0058] The bias power supply 32 is electrically connected to the bias electrode. In one embodiment, the base 111e constitutes the bias electrode. In another embodiment, the bias electrode may also be an electrode disposed in the electrostatic chuck 111c. The bias power supply 32 is configured to periodically apply bias energy BE having a waveform period CY to the bias electrode. That is, the bias energy BE is applied to the bias electrode in each cycle of the plurality of waveform periods CY. In one embodiment, each of the plurality of waveform periods CY is the waveform period of the bias energy BE applied to the bias electrode during the processing of the substrate W in the plasma processing apparatus 1. Each of the plurality of waveform periods CY is defined by a bias frequency. The bias frequency is, for example, a frequency of 50 kHz to 27 MHz. The duration of each of the plurality of waveform periods CY is the reciprocal of the bias frequency. The plurality of waveform periods CY appear sequentially in time. In the following description, the waveform period CY(m) represents the m-th waveform period among the plurality of waveform periods CY. That is, the waveform period CY(m) represents any waveform period among the plurality of waveform periods CY.

[0059] Here, refer to Figure 3 and Figure 4 . Figure 3 This is a timing diagram of an example of bias energy and the generator source frequency of the high-frequency power of the generator source. Figure 4 This is another timing diagram showing the bias energy and the generator source frequency relative to the high-frequency power of the generator source. (Example:) Figure 3 and Figure 4 As shown, in one embodiment, the bias energy BE can also be a bias high-frequency power having a bias frequency. In this case, as... Figure 2 As shown, the bias power supply 32 may also include a high-frequency signal generator 32g and an amplifier 32a. The high-frequency signal generator 32g generates a high-frequency signal. The amplifier 32a generates bias high-frequency power by amplifying the high-frequency signal input from the high-frequency signal generator 32g, and supplies the generated bias high-frequency power as bias energy BE to the bias electrode. Alternatively, the high-frequency signal generator 32g may be constructed from a programmable processor or a programmable logic device such as an FPGA. Furthermore, a D / A converter may be connected between the high-frequency signal generator 32g and the amplifier 32a.

[0060] When the bias energy BE is the bias high-frequency power, the bias power supply 32 is connected to the bias electrode via a matching converter 32m. The matching converter 32m includes a matching circuit. The matching circuit of the matching converter 32m has a variable impedance. The matching circuit of the matching converter 32m is controlled by the control unit 30c. The impedance of the matching circuit of the matching converter 32m is adjusted so that the impedance on the load side of the bias power supply 32 matches the output impedance of the bias power supply 32.

[0061] Figure 5 This is a timing diagram for another example of bias energy. For example... Figure 5 As shown, in another embodiment, the bias energy BE may also comprise a pulse of voltage applied to the bias electrode in each cycle of a plurality of waveform cycles CY. The voltage pulse used as the bias energy BE may be as follows: Figure 5 The example shown is a negative voltage pulse, but other voltage pulses are also possible. The voltage pulse used as the bias energy BE can have waveforms such as triangular waves or rectangular waves. The voltage pulse can also have any other arbitrary pulse waveform. When using a voltage pulse as the bias energy BE, it can also replace... Figure 2 The matching circuit 32m is shown, and a filter that blocks the high-frequency power RF of the generation source is connected between the bias power supply 32 and the bias electrode.

[0062] The bias power supply 32 is synchronized with the high-frequency power supply 31. Therefore, the synchronization signal used can also be applied from the bias power supply 32 to the high-frequency power supply 31. Alternatively, the synchronization signal can also be applied from the high-frequency power supply 31 to the bias power supply 32. Alternatively, the synchronization signal can also be applied to the high-frequency power supply 31 and the bias power supply 32 from other devices such as the control unit 30c.

[0063] The control unit 30c is configured to control the high-frequency power supply 31. The control unit 30c can be a processor such as a CPU. The control unit 30c can be part of the matching unit 31m, part of the high-frequency power supply 31, or a control unit separate from the matching unit 31m and the high-frequency power supply 31. Alternatively, the control unit 2 can also serve as the control unit 30c.

[0064] The control unit 30c is configured to set the generation source frequency of the high-frequency power RF generated during each phase period of the multiple phase periods SP of the multiple waveform periods CY. Figure 3 and Figure 4 In the example shown, the multiple waveform periods CY each contain N phase periods SP(1) to SP(N). N is an integer greater than or equal to 2. The N phase periods SP(1) to SP(N) divide the multiple waveform periods CY into N phase periods. In each period of the multiple waveform periods CY, the multiple phase periods SP can have the same duration or different durations. Furthermore, in the following description, the phase period SP(n) represents the nth phase period among the phase periods SP(1) to SP(N). That is, the phase period SP(n) represents any phase period in each of the multiple waveform periods CY. In addition, the phase period SP(m,n) represents the nth phase period in the waveform period CY(m). Hereinafter, an embodiment of setting the generation source frequency in the control unit 30c will be described. However, when the control unit 30c is part of the high-frequency power supply 31, the high-frequency power supply 31 can set the generation source frequency.

[0065] The control unit 30c provides feedback for setting the generator source frequency, as described below. In this feedback, the control unit 30c adjusts the generator source frequency of the high-frequency power RF during the phase period SP(m,n) based on changes in the degree of reflection of the generator source high-frequency power RF. In one example, the degree of reflection of the generator source high-frequency power RF is represented by the power level Pr of the reflected wave of the generator source high-frequency power RF output from the sensor 31s. The change in the degree of reflection is determined by using different generator source frequencies in the corresponding phase periods SP(n) of two or more waveform periods CY preceding the waveform period CY(m).

[0066] By using different generator source frequencies during the phase periods SP(n) of two or more waveform cycles CY, the relationship between the change in generator source frequency (frequency shift) and the degree of reflection of the high-frequency power of the generator source can be determined. Therefore, according to the plasma processing apparatus 1, the generator source frequency used during the phase periods SP(m,n) can be adjusted to reduce the degree of reflection based on the change in the degree of reflection. Furthermore, according to the plasma processing apparatus 1, the degree of reflection can be reduced rapidly in each of the multiple waveform cycles CY during which the bias energy BE is applied to the bias electrode of the substrate support portion 11.

[0067] In one implementation, the two or more waveform periods CY preceding the waveform period CY(m) include waveform period CY(m-M1) and waveform period CY(m-M2). Here, M1 and M2 are natural numbers that satisfy M1 > M2.

[0068] In one implementation, the waveform period CY(m-M1) is the waveform period CY(m-2Q), and the waveform period CY(m-M2) is the waveform period CY(mQ). Figure 3 In the example shown, "Q" and "M2" are "1", and "2Q" and "M1" are "2". "Q" can also be an integer greater than 2.

[0069] In the feedback, the control unit 30c applies a frequency shift from the generation source frequency f(m-M1,n) to the generation source frequency f(m-M2,n). Here, f(m,n) represents the generation source frequency of the high-frequency power RF used during the phase period SP(m,n). f(m,n) is represented by f(m,n) = f(m-M2,n) + Δ(m,n). Δ(m,n) represents the amount of frequency shift. A frequency shift is either a frequency decrease (downshift) or a frequency increase (upshift). If a frequency shift is a downshift, Δ(m,n) has a negative value. If a frequency shift is an upshift, Δ(m,n) has a positive value.

[0070] In addition, Figure 3 and Figure 4 In the waveform period CY(m-M1), the generation source frequencies of SP during multiple phase periods are the same (f0), but they can also be different. Additionally, in... Figure 3 and Figure 4 In the waveform period CY(m-M2), the generation source frequencies of SP during multiple phase periods are the same and are set to be down from frequency f0, but can also be up from frequency f0.

[0071] In the feedback, when the degree of reflection is reduced by using the generation source frequency f(m-M2,n) obtained by a frequency shift, the control unit 30c sets the generation source frequency f(m,n) to a frequency with a frequency shift relative to the generation source frequency f(m-M2,n). For example, when the power level Pr(m-M2,n) decreases from the power level Pr(m-M1,n) by a frequency shift, the control unit 30c sets the generation source frequency f(m,n) to a frequency with a frequency shift relative to the generation source frequency f(m-M2,n). Furthermore, Pr(m,n) represents the power level Pr of the reflected wave of the high-frequency power RF of the generation source during the phase period SP(m,n).

[0072] In one implementation, the amount of frequency shift Δ(m,n) in the phase period SP(m,n) can also be the same as the amount of frequency shift Δ(m-M2,n) in the phase period SP(m-M2,n). That is, the absolute value of the frequency shift Δ(m,n) can be the same as the absolute value of the frequency shift Δ(m-M2,n). Alternatively, the absolute value of the frequency shift Δ(m,n) can also be greater than the absolute value of the frequency shift Δ(m-M2,n). Alternatively, it can be configured such that the greater the degree of reflection in the phase period SP(m-M2,n) (e.g., the power level Pr(mQ,n) of the reflected wave), the greater the absolute value of the frequency shift Δ(m,n). For example, the absolute value of the frequency shift Δ(m,n) can also be determined as a function of the degree of reflection (e.g., the power level Pr(mQ,n) of the reflected wave).

[0073] In the feedback, it is possible that the degree of reflection may increase by using a generation source frequency f(m-M2,n) obtained by utilizing a frequency shift. For example, the power level Pr(m-M2,n) of the reflected wave may increase from the power level Pr(m-M1,n) of the reflected wave due to a frequency shift. In this case, the control unit 30c may also set the generation source frequency f(m,n) to a frequency with a different frequency shift relative to the generation source frequency f(m-M2,n). Furthermore, it is also possible to update the generation source frequency of the phase period SP(n) of two or more waveform periods preceding the waveform period CY(m) to have a frequency shift relative to the generation source frequency of the phase period SP(n) of the previous waveform period. In this case, if the degree of reflection (e.g., the power level Pr of the reflected wave) or their average value tends to increase during the phase period SP(n) of the two or more waveform periods, another frequency shift may be supplied to the generation source frequency of the phase period SP(n) of the waveform period CY(m). For example, the generation source frequency of SP(n) during the phase period of the waveform period CY(m) can also be set to a frequency with a different frequency shift relative to the generation source frequency of the earliest waveform period among the two or more waveform periods.

[0074] Furthermore, in the feedback, when using a source frequency f(m,n) obtained by a frequency shift, the degree of reflection may increase. For example, the power level Pr(m,n) of the reflected wave may increase from the power level Pr(m-M2,n) of the reflected wave due to the frequency shift. In this case, the control unit 30c can also set the source frequency in the phase period SP(n) within the waveform period CY(m+M3) to an intermediate frequency. The waveform period CY(m+M3) is the waveform period following the waveform period CY(m). M3 is a natural number, and M3 = M2 can also be satisfied. The intermediate frequency that can be set in the phase period SP(m+M3,n) is the frequency between f(m-M2,n) and f(m,n), or it can be the average value of f(m-M2,n) and f(m,n).

[0075] Furthermore, in the feedback, it is possible that when an intermediate frequency is used in the phase period SP(m+M3,n), the degree of reflection (e.g., power level Pr) may exceed a predetermined threshold. In this case, the control unit 30c may also set the source frequency generated in the phase period SP(n) within the waveform period CY(m+M4) to a frequency with a different frequency shift relative to the intermediate frequency. The waveform period CY(m+M4) is the waveform period following the waveform period CY(m+M3). M4 is a natural number, and M4 = M1 may also be satisfied. The threshold is preset. The absolute value of the amount of the other frequency shift Δ(m+M4,n) is greater than the absolute value of the amount of the first frequency shift Δ(m,n). In this case, it is possible to avoid the situation where the degree of reflection (e.g., the power level Pr of the reflected wave) cannot be reduced from a local minimum. In addition, the thresholds for each phase period SP of the multiple phase periods of the multiple waveform periods CY may be the same or different from each other.

[0076] The plasma processing apparatus 1 may also use a representative value of the measured values ​​during each phase period as the degree of reflection during each phase period. The representative value may be the average or maximum value of the measured values ​​during each phase period. In addition, the plasma processing apparatus 1 may also use at least one of the following as measured values: the power level Pr of the reflected wave, the ratio of the power level Pr of the reflected wave to the output power level of the high-frequency power RF of the generating source (hereinafter referred to as "reflectivity"), the phase difference θ between voltage V and current I, and the impedance Z of the load side of the high-frequency power supply 31.

[0077] The plasma processing apparatus 1 may also have the aforementioned sensor 31s and VI sensor, or may have a VI sensor instead of sensor 31s. The VI sensor measures the voltage V and current I in the power supply path of the high-frequency power RF source between the high-frequency power supply 31 and the high-frequency electrode. The VI sensor may also be connected between the high-frequency power supply 31 and the matching unit 31m. The VI sensor may also be connected between the matching unit 31m and the high-frequency electrode. For example, the VI sensor may also be connected between the junction of the electrical path extending from the matching unit 31m toward the bias electrode and the electrical path extending from the matching unit 32m toward the bias electrode, and the bias electrode. Alternatively, the VI sensor may also be connected between this junction and the matching unit 31m. The VI sensor may also be part of the matching unit 31m.

[0078] The generation source frequencies of SP during the multiple phase periods of each waveform period CY can also be varied according to the voltage V, current I, and the phase difference θ between voltage V and current I, so that the impedance on the load side of the high-frequency power supply 31 is close to the matching point. Furthermore, the variable impedance of the matching device 31m can also be adjusted according to the voltage V, current I, and phase difference θ, so that the impedance on the load side of the high-frequency power supply 31 is close to the matching point. Moreover, when the characteristic impedance of the power supply path of the generation source high-frequency power RF is 50Ω, the actual resistive component at the matching point is 50Ω, and the phase difference θ is 0°.

[0079] The following is for reference Figure 6 A method for controlling the generator source frequency of the generator source high-frequency power in an exemplary embodiment will be described. Figure 6 This is a flowchart of a method for controlling the generation source frequency of the generation source high-frequency power in an exemplary embodiment. Figure 6 The method shown begins in step STa or step STb.

[0080] In step STa, bias energy BE is supplied to the bias electrode. Step STb is performed in parallel with step STa. In step STb, high-frequency power RF from a high-frequency power source (e.g., high-frequency power source 31) is supplied to generate plasma in the chamber.

[0081] In step STc, the generation source frequency of the high-frequency power RF used in the multiple phase periods SP of the multiple waveform periods CY is set. Specifically, in step STc, the generation source frequency f(m,n) of the high-frequency power RF in the phase periods SP(m,n) within the waveform period CY(m) is adjusted according to the change in the degree of reflection of the high-frequency power RF (e.g., the power level Pr of the reflected wave). The change in the degree of reflection (e.g., the power level Pr of the reflected wave) is determined by using different generation source frequencies in the corresponding phase periods SP(n) of two or more waveform periods CY preceding the waveform period CY(m). For the adjustment of the generation source frequency used in the multiple phase periods SP of the multiple waveform periods CY, please refer to the description of the generation source frequency adjustment performed by the control unit 30c described above.

[0082] In the plasma processing apparatus 1, the high-frequency power supply 31 may also use multiple frequencies included in a pre-prepared initial frequency group. During multiple phase periods SP within the initial waveform period CY(1) of multiple waveform periods CY, multiple frequencies included in the initial frequency group are used respectively.

[0083] The following describes several implementation methods related to the determination of the initial frequency group.

[0084] The following is for reference Figure 7 . Figure 7 This is a timing diagram of another example of the bias energy and the generation source frequency of the high-frequency power of the generation source. In one embodiment, the control unit 30c controls the bias power supply 32 to apply the bias energy BE to the bias electrode in each of the plurality of reference periods RCY of the bias energy BE. Each of the plurality of reference periods RCY is a period defined by the aforementioned bias frequency and has the same time length as the plurality of waveform periods CY. That is, each of the plurality of reference periods RCY is a waveform period of the bias energy BE and has a time length that is the reciprocal of the bias frequency. Figure 7 In the example shown, the number of multiple reference periods RCY is K, including reference periods RCY(1) to RCY(K). The multiple reference periods RCY appear before the multiple waveform periods CY and appear in chronological order. As described above, in one embodiment, each of the multiple waveform periods CY is a waveform period of bias energy BE applied to the bias electrode during the processing of the substrate W in the plasma processing apparatus 1. Each of the multiple reference periods RCY is a waveform period of bias energy BE applied to the bias electrode to determine an initial frequency group during a preparation period prior to the processing period. During the preparation period, the initial frequency group can be determined under the conditions of the processing that will be performed during the processing period.

[0085] In order to generate plasma in the chamber during each of the multiple reference cycles RCY, the control unit 30c controls the high-frequency power supply 31 to generate high-frequency power RF. During the multiple waveform cycles CY, plasma can be generated with the substrate W placed on the substrate support 11. During the multiple reference cycles RCY, the substrate W may or may not be placed on the substrate support 11.

[0086] like Figure 7 As shown, each of the multiple reference periods RCY and multiple waveform periods CY contains multiple phase periods SP. That is, the multiple reference periods RCY and multiple waveform periods CY are each divided into N phase periods SP(1) to SP(N). N is an integer greater than or equal to 2. In each period of the multiple reference periods RCY and multiple waveform periods CY, the multiple phase periods SP may have the same time length or different time lengths. Furthermore, in the following description, the phase period SP(n) represents the nth phase period among the phase periods SP(1) to SP(N) of the multiple reference periods RCY and multiple waveform periods CY.

[0087] The control unit 30c controls the high-frequency power supply 31 to set the generation source frequencies used in the same phase period SP(n) of multiple reference periods RCY to multiple frequencies that are different from each other. The control unit 30c determines multiple appropriate frequencies for the generation source high-frequency power of each of the multiple phase periods SP by selecting an appropriate frequency that minimizes the degree of reflection of the generation source high-frequency power RF (e.g., the power level Pr of the reflected wave) in each phase period SP of the multiple frequencies. Figure 3 In the example shown, the generation source frequencies of each reference period RCY(1) to RCY(K) are set to a certain frequency, which is different from the generation source frequencies of the high-frequency power RF of the generation source in other reference periods of RCY(1) to RCY(K). Then, the degree of reflection (e.g., power level Pr) of each phase period SP(1) to SP(N) of each reference period RCY(1) to RCY(K) is determined. Then, based on the obtained degree of reflection, an appropriate frequency of the generation source high-frequency power RF of each phase period SP(1) to SP(N) is selected to minimize the degree of reflection of each phase period SP(1) to SP(N). Multiple appropriate frequencies for each phase period SP(1) to SP(N) are stored as multiple frequencies of an initial frequency group in the storage unit of the plasma processing apparatus 1.

[0088] In plasma processing apparatus 1, multiple appropriate frequencies of the high-frequency power RF of the generation source are required to suppress reflections by SP during multiple phases. Therefore, according to plasma processing apparatus 1, the degree of reflection of the high-frequency power of the generation source can be reduced in each of the multiple waveform periods CY during which bias energy BE is applied to the bias electrode.

[0089] In one embodiment, the control unit 30c can also control the high-frequency power supply 31 so that, after multiple reference periods RCY, multiple frequencies of the initial frequency group, i.e., the aforementioned multiple appropriate frequencies, are used as the generation source frequencies for each of the multiple phase periods SP within at least one waveform period of the multiple waveform periods CY. That is, the control unit 30c can control the high-frequency power supply 31 so that, within the phase period SP(n) of at least one waveform period of the multiple waveform periods CY, the appropriate frequency used for the phase period SP(n) among the multiple appropriate frequencies is used. The multiple appropriate frequencies can also be used as generation source frequencies for each of the multiple phase periods SP in all waveform periods CY.

[0090] Multiple appropriate frequencies, i.e. multiple frequencies of the initial frequency group, can also be used in multiple phase periods SP within the initial waveform period CY(1) of multiple waveform periods CY. Moreover, the above-mentioned feedback can also be performed in multiple waveform periods CY.

[0091] The following is for reference Figure 8 The method for determining the generator source frequency of the generator source high-frequency power in an exemplary embodiment will be described. Figure 8 This is a flowchart of a method for determining the generation source frequency of the generation source high-frequency power in an exemplary implementation. Figure 8 The method shown begins in step STAa or step STAb.

[0092] In step STAa, bias energy BE is supplied to the bias electrode in each of the multiple reference periods RCY. Step STAb is performed in parallel with step STAa. In step STAb, in each of the multiple reference periods RCY, high-frequency power RF of the generation source is supplied from a high-frequency power source (e.g., high-frequency power source 31) to generate plasma in the chamber. In step STAb, the generation source frequencies used in the same phase period SP(n) of the multiple reference periods RCY are respectively set to multiple frequencies that are different from each other.

[0093] In step STAc, several appropriate frequencies for the generation source high-frequency power RF used in each of the multiple phase periods SP are determined. Specifically, in step STAc, an appropriate frequency is selected that minimizes the degree of reflection (e.g., the power level of the reflected wave) of the generation source high-frequency power RF used in the generation source frequencies during the same phase period SP(n) of the multiple reference periods RCY.

[0094] Method MT may further include steps STAd and Ae. In step STAd, bias energy is applied to a bias electrode in each of a plurality of waveform periods CY following a plurality of reference periods RCY. Step STAe is performed at least partially in parallel with step STAd. In step STAe, a high-frequency power RF is supplied from a high-frequency power source (e.g., high-frequency power source 31) in each of the plurality of waveform periods CY to generate plasma in the chamber. The generation source frequency of the high-frequency power RF is set to a plurality of frequencies, i.e., a plurality of appropriate frequencies, of an initial frequency group during a plurality of phase periods SP of at least one or all of the plurality of waveform periods CY.

[0095] In addition, in the method MTA, multiple appropriate frequencies, i.e. multiple frequencies of the initial frequency group, can be used in multiple phase periods SP within the initial waveform period CY(1) of multiple waveform periods CY. Moreover, the above-mentioned feedback can also be performed in multiple waveform periods CY.

[0096] The following is for reference Figure 9 and Figure 10 . Figure 9 and Figure 10This is a timing diagram of another example of the bias energy and the generation source frequency of the generation source high-frequency power. In one embodiment, the control unit 30c controls the high-frequency power supply 31 to generate a generation source high-frequency power RF having multiple frequency components in order to generate plasma in the chamber during the reference period RCY of the bias energy BE. The reference period RCY is the waveform period preceding the multiple waveform periods CY. In one embodiment, the reference period RCY is the waveform period of the bias energy BE applied to the bias electrode to determine the initial frequency group during the preparation period before the aforementioned processing period. During the preparation period, the initial frequency group can be determined under the conditions of the processing performed during the processing period. The reference period RCY is the period defined by the aforementioned bias frequency and has the same time length as each waveform period of the multiple waveform periods CY. That is, the reference period RCY is the waveform period of the bias energy BE and has the time length of the reciprocal of the bias frequency. Similar to the case of each period of the multiple waveform periods CY, the bias energy BE is also applied to the bias electrode during the reference period RCY. During the multiple waveform periods CY, plasma can be generated while the substrate W is placed on the substrate support 11. During the reference period RCY, the substrate W may or may not be placed on the substrate support 11.

[0097] Figure 11 This is a diagram representing an example of the power spectrum of the high-frequency power of the generating source. Figure 11 In the diagram, the horizontal axis represents frequency, and the vertical axis represents the normalized power levels of multiple frequency components of the generated source high-frequency power. The generated source high-frequency power RF used in the reference period RCY includes a frequency component having a fundamental frequency f0 and multiple frequency components each having a frequency different from the fundamental frequency f0. The power levels of each of the multiple frequency components may be lower than the power level of the frequency component having the fundamental frequency f0. In one embodiment, the power levels of each of the multiple frequency components may be less than 1 / 10 of the power level of the frequency component having the fundamental frequency f0. In one embodiment, the fundamental frequency f0 may be the center frequency of the multiple frequencies of each of the multiple frequency components. The spacing between the multiple frequencies of each of the multiple frequency components may be fixed or different. In one embodiment, the spacing between the multiple frequencies of each of the multiple frequency components is less than the amount of frequency shift described later.

[0098] like Figure 9 and Figure 10As shown, the reference period RCY and the multiple waveform periods CY each contain multiple phase periods SP. That is, the reference period RCY and the multiple waveform periods CY are each divided into N phase periods SP(1) to SP(N). N is an integer greater than or equal to 2. The reference period RCY and the multiple waveform periods CY can also be divided into N phase periods SP(1) to SP(N). In the following explanation, the phase period SP(n) represents the nth phase period among the respective phase periods SP(1) to SP(N) of the reference period RCY and the multiple waveform periods CY.

[0099] The control unit 30c calculates multiple ratios, which are the ratios of the power levels Pr of the reflected waves of multiple frequency components in each of the multiple phase periods SP(1) to SP(n) within the reference period RCY to the power levels Pf of the traveling waves of the multiple frequency components. The control unit 30c can calculate the power levels Pr of the reflected waves of each of the multiple frequency components by analyzing the spectrum of the reflected waves output by the sensor 31s. In one example, the spectrum analysis can be performed using a fast Fourier transform or a discrete Fourier transform. The control unit 30c calculates the ratio with the smallest value among the multiple ratios. The control unit 30c determines multiple appropriate frequencies for the high-frequency power RF of the generation source in each of the multiple phase periods SP by determining the frequency of the frequency component that results in the smallest ratio in each of the multiple phase periods SP. The multiple appropriate frequencies for each phase period SP(1) to SP(n) are stored as multiple frequencies of the initial frequency group in the storage unit of the plasma processing device 1.

[0100] According to the plasma processing apparatus 1, by using a high-frequency power RF of the generation source having multiple frequency components within a reference period RCY, multiple appropriate frequencies of the high-frequency power RF of the generation source to be used in order to reduce the degree of reflection during multiple phase periods SP can be determined in a short time. Therefore, in each waveform period of multiple waveform periods to which the bias energy BE is applied to the bias electrode, the degree of reflection of the high-frequency power RF of the generation source can be reduced.

[0101] In one embodiment, multiple appropriate frequencies, i.e. multiple frequencies of the initial frequency group, may be used in multiple phase periods SP within the initial waveform period CY(1) of multiple waveform periods CY. Moreover, the above-mentioned feedback may also be performed in multiple waveform periods CY.

[0102] The plasma processing apparatus 1 can fine-tune the generation source frequency used in each phase period of SP during the multiple phase periods of the multiple waveform periods CY by using the aforementioned frequency shift, thereby reducing the degree of reflection.

[0103] The following is for reference Figure 12The method for determining the generator source frequency of the generator source high-frequency power in an exemplary embodiment will be described. Figure 12 This is a flowchart illustrating a method for determining the generation source frequency of the generation source high-frequency power in another exemplary embodiment. Figure 12 The method shown begins in step STBa or step STBb.

[0104] In step STBa, bias energy BE is supplied to the bias electrode during the reference period RCY. Step STBb is performed in parallel with step STBa. In step STBb, during the reference period RCY, high-frequency power RF from a high-frequency power source (e.g., high-frequency power source 31) is supplied from the high-frequency power source to generate plasma in the chamber. The high-frequency power RF supplied during the reference period RCY contains multiple frequency components as described above.

[0105] In step STBc, the aforementioned multiple ratios are calculated. As described above, the multiple ratios are the ratios of the power levels of the reflected waves of the multiple frequency components in each of the multiple phase periods SP within the reference period RCY to the power levels of the traveling waves of the multiple frequency components. In step STBd, the minimum ratio among the multiple ratios is calculated. The minimum ratio is calculated for each of the multiple phase periods SP within the reference period RCY.

[0106] In step STBe, as described above, multiple appropriate frequencies for the generation source high-frequency power RF for each of the multiple phase periods SP(1) to SP(N) are determined. The multiple appropriate frequencies are determined by identifying the frequency of the frequency component that results in the minimum ratio among the multiple frequency components in each of the multiple phase periods SP(1) to SP(N).

[0107] The method MTB may also include steps STBf, STBg, and STBh. In step STBf, bias energy is applied to the bias electrode in each of the multiple waveform periods CY following the reference period RCY. Step STBg is performed in parallel with step STBf. In step STBg, a high-frequency power RF for generating plasma is supplied from a high-frequency power source (e.g., high-frequency power source 31) to generate plasma in the chamber. In step STBg, multiple frequencies of the initial frequency group, i.e., multiple appropriate frequencies, are used as the generation source frequencies of the generation source high-frequency power RF for each phase period SP within at least one of the multiple waveform periods CY. At least one waveform period may be the initial waveform period CY(1) of the multiple waveform periods CY.

[0108] In step STBh, the generation source frequency is set in each phase period of the plurality of phase periods SP within the waveform period following at least one of the aforementioned waveform periods in the plurality of waveform periods CY. That is, in step STBh, the aforementioned feedback is performed.

[0109] Alternatively, the plasma processing apparatus 1 can also generate multiple initial frequency groups corresponding to each of the multiple processes by generating the aforementioned initial frequency groups under various conditions of the multiple processes. The plasma processing apparatus 1 can also store the multiple initial frequency groups in its storage unit in association with the identification information of each of the multiple processes. The plasma processing apparatus 1 can also select an initial frequency group associated with the executed process from the multiple initial frequency groups and use the selected initial frequency group as described above.

[0110] In one embodiment, the plasma processing apparatus 1 may also select an optimal setting corresponding to the process to be performed among multiple processes from a plurality of pre-prepared optimal settings, and use the selected optimal setting. The plurality of optimal settings each include the optimal matching set of the matching device 31m and an initial frequency group. Furthermore, the plurality of optimal settings may also be stored in the storage unit of the plasma processing apparatus 1, each associated with identification information of the multiple processes.

[0111] Figure 13 This is a diagram illustrating an example of the structure of a matcher. (For example...) Figure 13 As shown, the matching unit 31m may also include a first variable capacitor 331 and a second variable capacitor 332. The first variable capacitor 331 is connected between node 333 and ground. Node 333 is disposed on a power supply path connecting the high-frequency power supply 31 and the high-frequency electrode. The high-frequency power RF generated is supplied to the high-frequency electrode via this power supply path. The second variable capacitor 332 is connected between node 333 and the high-frequency electrode. The capacitance C1 of the first variable capacitor 331 and the capacitance C2 of the second variable capacitor 332 can be controlled, for example, by control unit 2 or control unit 30c. The optimal setting of the matching unit 31m includes the variable values ​​of the first variable capacitor 331 and the second variable capacitor 332. The variable value of the first variable capacitor 331 is the capacitance C1 or determines the position of the capacitance C1. The variable value of the second variable capacitor 332 is, for example, the capacitance C2 or determines the position of the capacitance C2.

[0112] In one embodiment, the matcher 31m uses a pre-prepared optimal matcher setting corresponding to the processing performed in the plasma processing apparatus 1 to set the variable values ​​of the first variable capacitor 331 and the second variable capacitor 332 in the initial waveform period CY(1). The optimal matcher setting is included in the optimal settings selected as described above. Alternatively, the high-frequency power supply 31 may use multiple frequencies from a pre-prepared initial frequency group corresponding to the processing performed in the plasma processing apparatus 1 in multiple phase periods SP within the initial waveform period CY(1). The initial frequency groups are included in the optimal settings selected as described above.

[0113] In one embodiment, the above-described processing period may also include an ignition period before or just before multiple waveform cycles CY. During ignition, bias energy BE is periodically supplied to the bias electrode, and high-frequency power RF of the generation source with a fixed generation source frequency is supplied to the high-frequency electrode. The generation source frequency during ignition is predetermined to be a frequency suitable for plasma ignition. During ignition, the variable values ​​of the first variable capacitor 331 and the second variable capacitor 332 approach the optimal matched set from their initial values.

[0114] The following is for reference Figure 14 Several implementation methods related to the determination of the optimal settings will be described. Figure 14 This is a flowchart illustrating a method for determining the optimal settings for an exemplary implementation. Whenever a new processing scheme is registered in the storage unit of the plasma processing apparatus 1, the following steps are performed: Figure 14 The method shown is MTC.

[0115] In step STCa of method MTC, control unit 30c sequentially uses multiple matching devices of first variable capacitor 331 and second variable capacitor 332 to set the conditions under processing, and generates multiple provisional settings. Step STCa includes steps STCa1 and STCa2.

[0116] In step STCa1, the variable values ​​of the first variable capacitor 331 and the second variable capacitor 332 are set to the values ​​included in the unused matching set among the multiple matching set. Furthermore, in method MTC, the variable values ​​of the first variable capacitor 331 and the second variable capacitor 332 are set discretely among the multiple matching set. The discrete magnitude of the variable values ​​of the first variable capacitor 331 and the second variable capacitor 332 in method MTC can also be specified in the processing scheme.

[0117] In step STCa2, a provisional frequency group comprising multiple provisional frequencies is determined. In one embodiment, the control unit 30c may also generate a provisional frequency group that includes multiple appropriate frequencies obtained by performing steps STAa to STAc of method MTA as multiple provisional frequencies. Alternatively, in step STCa2, a provisional frequency group is generated that includes multiple appropriate frequencies obtained by performing steps STBa to STe of method MTB as multiple provisional frequencies. The control unit 30c generates a provisional setting that includes the generated provisional frequency group and the current matcher setting.

[0118] In step STCJ, control unit 30c determines whether the stop condition is met. The stop condition is met if there are no unused matcher settings among the multiple matcher settings. If there are unused matcher settings among the multiple matcher settings, control unit 30c returns to step STCa1 and uses the unused matcher setting. Then, control unit 30c executes step STCa2.

[0119] When the stopping condition is met in step STCJ, multiple provisional settings are obtained. Then, in step STCb, the control unit 30c determines the provisional setting that minimizes the reflection of the high-frequency power RF of the generation source during the waveform period. The degree of reflection can be the average value during the waveform period (e.g., the average value of the power level Pr of the reflected wave). The control unit 30c stores the matched set and provisional frequency group included in the determined provisional settings in the storage unit of the plasma processing apparatus 1 as the optimal matched set and initial frequency group corresponding to the above-described process. That is, the control unit 30c stores the matched set and provisional frequency group included in the determined provisional settings in the storage unit of the plasma processing apparatus 1 as the optimal setting including the optimal matched set and initial frequency group corresponding to the above-described process.

[0120] The above descriptions illustrate various illustrative embodiments, but the implementation is not limited to these illustrative embodiments. Various additions, omissions, substitutions, and modifications can be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

[0121] As described above, in other embodiments, the plasma processing apparatus may also be an inductively coupled plasma processing apparatus, an ECR plasma processing apparatus, a helical wave excited plasma processing apparatus, or a surface wave plasma processing apparatus. In any plasma processing apparatus, the high-frequency power RF of the generation source is also used for plasma generation, and the generation source frequency of the high-frequency power RF used in the multiple phases SP of multiple waveform periods CY is adjusted as described above with respect to plasma processing apparatus 1.

[0122] Alternatively, the generation frequency of the high-frequency power RF of the generation source in the phase period SP(m,n) can be determined by using two or more different generation source frequencies obtained by using different generation source frequencies in the corresponding phase periods SP(n) of two or more waveform periods CY(m) before the waveform period CY(m), as the frequency that minimizes the degree of reflection. The frequency that minimizes the degree of reflection can also be determined by using the least squares method of these different frequencies and their corresponding degrees of reflection.

[0123] In addition, the present invention also includes the following further embodiments EA1~EA8, EB1~EB4, and EC1~EC13.

[0124] [EA1]

[0125] A plasma processing apparatus comprising:

[0126] Chamber;

[0127] The substrate support portion disposed within the aforementioned cavity has a bias electrode;

[0128] A high-frequency power supply configured to generate high-frequency power to generate plasma within the aforementioned cavity;

[0129] The bias power supply is configured to apply bias energy to the bias electrodes in each of a plurality of cycles defined by a bias frequency.

[0130] The sensor is configured to output a reflected wave of the high-frequency power returned from the load of the aforementioned high-frequency power source; and

[0131] It is configured as a control unit capable of controlling the aforementioned high-frequency power supply.

[0132] The control unit described above is configured to set the frequency of the high-frequency power during each phase period of the plurality of phase periods of the plurality of cycles.

[0133] The control unit is configured to adjust the frequency of the high-frequency power in the nth phase period of the mth cycle based on the change in the power level of the reflected wave output from the sensor when different frequencies of the high-frequency power are used in the corresponding phase periods of two or more cycles preceding the mth cycle.

[0134] [EA2]

[0135] According to the plasma processing apparatus described in Embodiment EA1, wherein...

[0136] The aforementioned two or more cycles include the first cycle and the second cycle following the first cycle.

[0137] The control unit is configured to, when the power level of the reflected wave is reduced by applying a frequency shift, either down-frequency or up-frequency, to the frequency of the high-frequency power in the nth phase period of the mth period, to a frequency that has the aforementioned frequency shift relative to the frequency of the high-frequency power in the nth phase period of the second period, to the frequency of the high-frequency power in the nth phase period of the mth period.

[0138] [EA3]

[0139] According to the plasma processing apparatus described in Embodiment EA2, wherein...

[0140] The control unit is configured to, when the power level of the reflected wave increases by setting the frequency of the high-frequency power in the nth phase period of the third period after the mth period among the plurality of periods to an intermediate frequency between the frequency of the high-frequency power in the nth phase period of the second period and the frequency of the high-frequency power in the nth phase period of the mth period, the frequency of the high-frequency power in the third period after the mth period among the plurality of periods is set to a frequency that has the frequency shift relative to the frequency of the high-frequency power in the nth phase period of the second period.

[0141] [EA4]

[0142] According to the plasma processing apparatus described in Embodiment EA3, wherein...

[0143] The control unit is configured such that, when the power level of the reflected wave during the nth phase period of the third cycle is greater than a threshold, it sets the frequency of the high-frequency power during the nth phase period of the fourth cycle after the third cycle of the plurality of cycles to a frequency with a different frequency shift relative to the intermediate frequency, wherein the other frequency shift has an absolute value greater than the absolute value of the first frequency shift.

[0144] [EA5]

[0145] According to the plasma processing apparatus described in Embodiment EA2, wherein...

[0146] The absolute value of the frequency shift of the high-frequency power during the nth phase period within the mth period is greater than the absolute value of the frequency shift of the high-frequency power during the nth phase period within the second period.

[0147] [EA6]

[0148] According to the plasma processing apparatus described in Embodiment EA1, wherein...

[0149] The aforementioned two or more cycles include the first cycle and the second cycle following the first cycle.

[0150] The control unit is configured to, when the power level of the reflected wave is increased by applying a frequency shift, either down-frequency or up-frequency, to the frequency of the high-frequency power in the nth phase period of the second period, to the frequency of the high-frequency power in the nth phase period of the first period, a frequency with a different frequency shift relative to the frequency of the high-frequency power in the nth phase period of the second period.

[0151] [EA7]

[0152] According to the plasma processing apparatus described in any one of embodiments EA1 to EA6, wherein...

[0153] The aforementioned bias energy is high-frequency power having the aforementioned bias frequency, or a pulse of voltage applied to the aforementioned bias electrode in each of the aforementioned multiple cycles.

[0154] [EA8]

[0155] A method for controlling the frequency of high-frequency power, comprising:

[0156] The step of applying bias energy to a bias electrode of a substrate support disposed in a cavity of a plasma processing apparatus, wherein the bias energy is applied to the bias electrode in each of a plurality of cycles defined by a bias frequency.

[0157] The steps of supplying high-frequency power from a high-frequency power source to generate plasma within the cavity; and

[0158] The step of setting the frequency of the high-frequency power in each phase period of the plurality of cycles of the aforementioned high-frequency power supply.

[0159] The frequency of the high-frequency power in the nth phase period of the mth cycle is adjusted based on the change in the power level of the reflected wave of the high-frequency power when different frequencies of the high-frequency power are used in the corresponding phase periods of two or more cycles preceding the mth cycle.

[0160] [EB1]

[0161] A plasma processing apparatus comprising:

[0162] Chamber;

[0163] The substrate support portion disposed within the aforementioned cavity has a bias electrode;

[0164] A high-frequency power supply configured to generate high-frequency power to generate plasma within the aforementioned cavity;

[0165] The bias power supply is configured to apply bias energy to the bias electrodes in each of a plurality of cycles defined by a bias frequency.

[0166] The sensor is configured to output a reflected wave of the high-frequency power returned from the load of the aforementioned high-frequency power source; and

[0167] It is configured as a control unit capable of controlling the aforementioned bias power supply and the aforementioned high-frequency power supply.

[0168] The aforementioned control unit is configured as follows:

[0169] The bias power supply can be controlled such that the bias energy is applied to the bias electrode in each of a plurality of reference periods, each comprising a plurality of phase periods and defined by the bias frequency.

[0170] The high-frequency power supply can be controlled such that the frequencies of the high-frequency power used during the same phase of the multiple reference cycles are set to multiple frequencies that are different from each other.

[0171] Multiple appropriate frequencies for the high-frequency power of each of the multiple phase periods can be determined by selecting an appropriate frequency that minimizes the power level of the reflected wave output from the sensor during each of the multiple phase periods.

[0172] [EB2]

[0173] According to embodiment EB1, the plasma processing apparatus wherein...

[0174] The control unit controls the high-frequency power supply so that, after the plurality of reference cycles, the plurality of appropriate frequencies are used as the frequency of the high-frequency power during each phase period of the plurality of phase periods within at least one of the plurality of cycles.

[0175] [EB3]

[0176] According to embodiment EB2, the plasma processing apparatus wherein...

[0177] During the aforementioned multiple cycles, the substrate is subjected to plasma treatment while it is placed on the substrate support.

[0178] [EB4]

[0179] A method for determining the frequency of high-frequency power, comprising:

[0180] The step of applying bias energy to a bias electrode of a substrate support disposed in a cavity of a plasma processing apparatus, wherein the bias energy is applied to the bias electrode in each of a plurality of reference periods comprising a plurality of phase periods and defined by a bias frequency.

[0181] In the step of supplying high-frequency power from a high-frequency power source to generate plasma in the cavity during the aforementioned plurality of reference cycles, the frequencies of the high-frequency power used during the same phase of the plurality of reference cycles are respectively set to a plurality of frequencies that are different from each other; and

[0182] The step of determining multiple appropriate frequencies for the high-frequency power in each of the multiple phase periods is to select an appropriate frequency among the multiple frequencies that minimizes the power level of the reflected wave of the high-frequency power in each of the multiple phase periods.

[0183] [EC1]

[0184] A plasma processing apparatus comprising:

[0185] Chamber;

[0186] The substrate support portion disposed within the aforementioned cavity has a bias electrode;

[0187] A high-frequency power supply configured to generate high-frequency power to generate plasma within the aforementioned cavity;

[0188] The bias power supply is configured to apply bias energy to the bias electrodes in each of a plurality of cycles defined by a bias frequency.

[0189] The sensor is configured to output a reflected wave of the high-frequency power returned from the load of the aforementioned high-frequency power source; and

[0190] The control unit that controls the aforementioned high-frequency power supply

[0191] The aforementioned control unit is configured as follows:

[0192] The high-frequency power supply can be controlled to generate high-frequency power with multiple frequency components, thereby generating plasma in the cavity during a reference period defined by the bias frequency and during which the bias energy is applied to the bias electrode.

[0193] It is possible to obtain multiple ratios and find the smallest of these ratios, wherein the multiple ratios are the ratios of the power levels of the reflected waves of the multiple frequency components in each of the multiple phase periods within the reference period to the power levels of the traveling waves of the multiple frequency components.

[0194] Multiple appropriate frequencies for the aforementioned high-frequency power in each of the multiple phase periods can be determined by identifying the frequency of the frequency component that results in the minimum ratio among the multiple frequency components in each of the multiple phase periods.

[0195] [EC2]

[0196] According to the plasma processing apparatus of embodiment EC1, wherein,

[0197] The aforementioned multiple frequency components include a component having a fundamental frequency and multiple components each having a frequency different from the fundamental frequency.

[0198] The power levels of each of the aforementioned components are lower than the power levels of the aforementioned components having the aforementioned fundamental frequency.

[0199] [EC3]

[0200] According to the plasma processing apparatus of embodiment EC2, wherein,

[0201] The power level of each of the aforementioned components is less than 1 / 10 of the power level of the aforementioned component having the aforementioned fundamental frequency.

[0202] [EC4]

[0203] According to the plasma processing apparatus of embodiment EC2 or EC3, wherein,

[0204] The aforementioned fundamental frequency is the center frequency among the multiple frequencies of each of the aforementioned frequency components.

[0205] [EC5]

[0206] According to the plasma processing apparatus described in any one of embodiments EC1 to EC4, wherein,

[0207] The control unit controls the high-frequency power supply so that the multiple appropriate frequencies are used as the frequency of the high-frequency power during each phase period of the multiple phase periods within at least one of the multiple cycles.

[0208] [EC6]

[0209] According to the plasma processing apparatus of embodiment EC1, wherein,

[0210] The control unit is configured to adjust the frequency of the high-frequency power in the nth phase period of the mth cycle after at least one of the multiple cycles, based on the change in the power level of the reflected wave output from the sensor when different frequencies of the high-frequency power are used in the corresponding phase periods of two or more cycles preceding the mth cycle.

[0211] [EC7]

[0212] According to the plasma processing apparatus of embodiment EC6, wherein...

[0213] The aforementioned two or more cycles include the first cycle and the second cycle following the first cycle.

[0214] The control unit is configured to, when the power level of the reflected wave is reduced by applying a frequency shift, either down-frequency or up-frequency, to the frequency of the high-frequency power in the nth phase period of the mth period, to a frequency that has the aforementioned frequency shift relative to the frequency of the high-frequency power in the nth phase period of the second period, to the frequency of the high-frequency power in the nth phase period of the mth period.

[0215] [EC8]

[0216] According to the plasma processing apparatus of embodiment EC7, wherein...

[0217] The control unit is configured to, when the power level of the reflected wave increases by setting the frequency of the high-frequency power in the nth phase period of the third period after the mth period among the plurality of periods to an intermediate frequency between the frequency of the high-frequency power in the nth phase period of the second period and the frequency of the high-frequency power in the nth phase period of the mth period, the frequency of the high-frequency power in the third period after the mth period among the plurality of periods is set to a frequency that has the frequency shift relative to the frequency of the high-frequency power in the nth phase period of the second period.

[0218] [EC9]

[0219] According to the plasma processing apparatus of embodiment EC8, wherein...

[0220] The control unit is configured such that, when the power level of the reflected wave during the nth phase period of the third cycle is greater than a threshold, it sets the frequency of the high-frequency power during the nth phase period of the fourth cycle after the third cycle of the plurality of cycles to a frequency with a different frequency shift relative to the intermediate frequency, wherein the other frequency shift has an absolute value greater than the absolute value of the first frequency shift.

[0221] [EC10]

[0222] According to the plasma processing apparatus of embodiment EC7, wherein...

[0223] The absolute value of the frequency shift of the high-frequency power during the nth phase period within the mth period is greater than the absolute value of the frequency shift of the high-frequency power during the nth phase period within the second period.

[0224] [EC11]

[0225] According to the plasma processing apparatus of embodiment EC6, wherein...

[0226] The aforementioned two or more cycles include the first cycle and the second cycle following the first cycle.

[0227] The control unit is configured to, when the power level of the reflected wave is increased by applying a frequency shift, either down-frequency or up-frequency, to the frequency of the high-frequency power in the nth phase period of the second period, to the frequency of the high-frequency power in the nth phase period of the first period, a frequency with a different frequency shift relative to the frequency of the high-frequency power in the nth phase period of the second period.

[0228] [EC12]

[0229] According to any one of embodiments EC1 to EC11, the plasma processing apparatus wherein,

[0230] The aforementioned bias energy is high-frequency power having the aforementioned bias frequency, or a pulse of negative voltage applied to the aforementioned bias electrode in each of the aforementioned multiple cycles.

[0231] [EC13]

[0232] A method for determining the frequency of high-frequency power, comprising:

[0233] The step of applying bias energy to a bias electrode of a substrate support disposed in a cavity of a plasma processing apparatus, wherein the bias energy is applied to the bias electrode during a reference period defined by a bias frequency.

[0234] In the aforementioned reference period, the step of supplying high-frequency power from a high-frequency power source to generate plasma in the aforementioned chamber, wherein the high-frequency power comprises multiple frequency components;

[0235] The step of obtaining multiple ratios, wherein the multiple ratios are the ratios of the power levels of the reflected waves of the multiple frequency components in each of the multiple phase periods within the reference period to the power levels of the traveling waves of the multiple frequency components.

[0236] The steps to find the smallest ratio among the above ratios; and

[0237] The step of determining multiple appropriate frequencies for the high-frequency power for each of the multiple phase periods by determining the frequency of the frequency component that causes the minimum ratio among the multiple frequency components in each of the multiple phase periods.

[0238] Based on the above description, various embodiments of the present invention have been described in this specification for illustrative purposes, and various modifications can be made without departing from the scope and spirit of the invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are given by the appended claims.

[0239] Explanation of reference numerals in the attached figures

[0240] 1…Plasma processing device, 10…Plasma processing chamber, 11…Substrate support, 31…High-frequency power supply, 32…Bias power supply, 31s…Sensor, 30c…Control unit.

Claims

1. A plasma processing device, characterized in that, include: Plasma processing chamber; The substrate support portion is disposed within the plasma processing chamber; Bias electrode disposed within the substrate support portion; A bias power supply configured to apply bias energy with multiple cycles to the bias electrode; A first high-frequency power supply is coupled to the plasma processing chamber and is configured to generate a first high-frequency power. The sensor is configured to output at least one parameter in the power supply path that provides the first high-frequency power. and Control Department The control unit is configured to set the frequency of the first high-frequency power in each of the multiple periods within each cycle of the bias energy, and is configured to adjust the frequency in the nth period within the m-th cycle based on the output of the sensor in the nth period within one or more cycles preceding the m-th cycle among the multiple cycles.

2. The plasma processing apparatus as described in claim 1, characterized in that: The sensor is a directional coupler configured to output reflected waves returned from the load of the first high-frequency power supply.

3. The plasma processing apparatus as described in claim 1, characterized in that: The sensor is a VI sensor, configured to measure the voltage and current in the power supply path of the first high-frequency power.

4. The plasma processing apparatus as described in claim 1, characterized in that: The first high-frequency power has multiple frequency components simultaneously in one or more cycles prior to the m-th cycle.

5. The plasma processing apparatus as described in claim 1, characterized in that: The first high-frequency power has frequencies that are different from each other in two or more cycles prior to the m-th cycle.

6. The plasma processing apparatus as described in claim 1, characterized in that: The bias energy has a second high-frequency power.

7. The plasma processing apparatus as described in claim 1, characterized in that: The bias energy has a voltage pulse.

8. The plasma processing apparatus as described in claim 1, characterized in that: The plurality of periods in each of the plurality of cycles have the same number and the same length.

9. The plasma processing apparatus as described in claim 1, characterized in that: The first high-frequency power has a frequency of 13MHz to 150MHz, and the plurality of cycles are defined by a frequency of 50kHz to 27MHz.

10. A plasma processing apparatus, characterized in that, include: Plasma processing chamber; The substrate support portion is disposed within the plasma processing chamber; Bias electrode disposed within the substrate support portion; A first high-frequency power supply is coupled to the plasma processing chamber and is configured to generate a first high-frequency power. The second high-frequency power supply is configured to apply a second high-frequency power with multiple cycles to the bias electrode. The sensor is configured to output at least one parameter in the power supply path that provides the first high-frequency power. and The control unit is configured to set the frequency of the first high-frequency power individually in each of the multiple periods within each cycle of the second high-frequency power, based on the output of the sensor.

11. The plasma processing apparatus as described in claim 10, characterized in that: The sensor is a directional coupler configured to output reflected waves returned from the load of the first high-frequency power supply.

12. The plasma processing apparatus as claimed in claim 11, characterized in that: The sensor is a VI sensor, configured to measure the voltage and current in the power supply path of the first high-frequency power.

13. The plasma processing apparatus as described in claim 10, characterized in that: The first high-frequency power has a frequency of 13MHz to 150MHz, and the plurality of cycles are defined by a frequency of 50kHz to 27MHz.

14. A plasma processing apparatus, characterized in that, include: Plasma processing chamber; The substrate support portion is disposed within the plasma processing chamber; Bias electrode disposed within the substrate support portion; A high-frequency power supply, coupled to the plasma processing chamber, is configured to generate high-frequency power. A voltage pulse generator configured to apply a voltage pulse signal with multiple cycles to the bias electrode; A sensor configured to output at least one parameter in a power supply path that provides the high-frequency power. and The control unit is configured to individually set the frequency of the high-frequency power in each of the multiple periods within each cycle of the voltage pulse signal, based on the output of the sensor.

15. The plasma processing apparatus as described in claim 14, characterized in that: The sensor is a directional coupler configured to output reflected waves returned from the load of the high-frequency power supply.

16. The plasma processing apparatus as described in claim 14, characterized in that: The sensor is a VI sensor, configured to measure the voltage and current in the power supply path of the high-frequency power.

17. The plasma processing apparatus as described in claim 14, characterized in that: The high-frequency power has a frequency of 13MHz to 150MHz, and the multiple cycles are defined by a frequency of 50kHz to 27MHz.

Images