Plasma processing apparatus, power supply system, control method, and program

Abstract

A power supply system of this disclosed plasma processing device includes a high-frequency power supply, a bias power supply, and a power supply control unit. The high-frequency power supply generates high-frequency power for plasma generation. The bias power supply supplies an electrical bias to a substrate support. The power supply control unit periodically modulates the power level of the high-frequency power during the repetition of a modulation cycle including at least two sub-periods. The power supply control unit is configured so as to, on the basis of changes in the degree of reflection of the high-frequency power and changes in the frequency of the high-frequency power in an n-th phase period during the repetition of the preceding modulation cycle, adjust the frequency of the high-frequency power for the n-th phase period in the modulation cycle included in a feedback period subsequent to the start time of each of the at least two sub-periods.

Description

Plasma processing apparatus, power supply system, and control method

[0001] SUMMARY Exemplary embodiments of the present disclosure relate to a plasma processing apparatus, a power supply system, and a control method.

[0002] A plasma processing apparatus is used in plasma processing of a substrate. In the plasma processing apparatus, bias high frequency power is used to attract ions from a plasma generated in a chamber to the substrate. Patent Document 1 listed below discloses a plasma processing apparatus in which the power level and frequency of the bias high frequency power are modulated.

[0003] Japanese Patent Application Laid-Open No. 2009-246091

[0004] The present disclosure provides a technique for suppressing reflection of high frequency power.

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, and a power supply system. The substrate support is located within the chamber. The power supply system includes a radio frequency power supply, a bias power supply, and a power supply controller. The radio frequency power supply is configured to supply radio frequency power to generate plasma within the chamber of the plasma processing apparatus. The bias power supply is configured to supply an electrical bias to the substrate support repeatedly at a time interval of a waveform period to attract ions from the plasma to a substrate on the substrate support located within the chamber. The power supply controller is configured to periodically modulate the power level of the radio frequency power in repetition of the modulation period. The modulation period includes a plurality of subperiods. The plurality of subperiods includes at least two subperiods in which the power level of the radio frequency power is set to a level greater than zero and different from each other. Each of the at least two subperiods includes a feedback period continuing from a start point thereof. The power supply control unit is configured to adjust the frequency of the high-frequency power for the nth phase period within a modulation cycle included in the feedback period based on changes in the frequency of the high-frequency power during the nth phase period in the repetition of the preceding modulation cycle and changes in the degree of reflection of the high-frequency power, so as to suppress the degree of reflection of the high-frequency power.

[0006] According to one exemplary embodiment, it is possible to suppress reflection of high frequency power.

[0007] FIG. 1 is a diagram for explaining an example configuration of a plasma processing system. FIG. 2 is a diagram for explaining an example configuration of a capacitively coupled plasma processing apparatus. FIG. 3 is a diagram showing an example waveform of an electrical bias. FIG. 4 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 5 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 6 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 7 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 8 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 9 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 10 is an example timing chart related to a power supply system according to an exemplary embodiment. FIG. 11 is an example timing chart related to a power supply system according to an exemplary embodiment. Fig. 18(a) is a flowchart of a control method according to an exemplary embodiment, and Fig. 18(b) is a flowchart of step STa shown in Fig. 18(a). Fig. 18(b) is a flowchart showing an example of processing in step STd shown in Fig. 18(b). Fig. 19 is a flowchart showing another example of processing in step STd shown in Fig. 18(b). Fig. 21 is a flowchart showing an example of processing in step ST7a shown in Fig. 21. Fig. 22 is a timing chart related to a power supply system according to an exemplary embodiment.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] FIG. 1 is a diagram illustrating an exemplary configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0010] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP).

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes 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 include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is realized, for example, by a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a programmable logic device such as a CPU (Central Processing Unit) or an FPGA (Field-Programmable Gate Array). The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0012] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0013] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms 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 showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The substrate support 11 is electrically insulated from the housing of the plasma processing chamber 10.

[0014] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0015] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member.

[0016] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0017] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0018] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0019] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0020] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0021] The power supply system 30 includes a high frequency power supply 31 and a bias power supply 32. The power supply system 30 may further include a DC power supply 38. The high frequency power supply 31 constitutes the plasma generation unit 12 of one embodiment. The high frequency power supply 31 is configured to generate high frequency power. In the following description, the high frequency power generated by the high frequency power supply 31 is referred to as source high frequency power HF. The source high frequency power HF has a frequency. In the following description, the frequency of the source high frequency power HF is referred to as source frequency. The source high frequency power HF has a sinusoidal waveform whose frequency is the source frequency. The source frequency may be a frequency within a range of 10 MHz to 150 MHz.

[0022] The high frequency power supply 31 is electrically connected to the high frequency electrode via a matching box 33 and is configured to supply source high frequency power HF to the high frequency electrode. The high frequency electrode may be provided within the substrate support 11. The high frequency electrode may be at least one electrode provided within the conductive member or ceramic member 1111a of the base 1110. Alternatively, the high frequency electrode may be an upper electrode. When the source high frequency power HF is supplied to the high frequency electrode, plasma is generated from the gas within the chamber 10.

[0023] The matching circuit 33 has a variable impedance. The variable impedance of the matching circuit 33 is set to reduce reflection of the source high frequency power HF from the load. The matching circuit 33 can be controlled by, for example, the control unit 2.

[0024] In one embodiment, the high frequency power supply 31 may include a signal generator 31g, a D / A converter 31c, and an amplifier 31a. The signal generator 31g generates a high frequency signal having a source frequency f. The signal generator 31g may be configured with a programmable logic device such as a programmable processor or a field-programmable gate array (FPGA).

[0025] The output of the signal generator 31g is connected to the input of the D / A converter 31c. The D / A converter 31c converts the high frequency signal from the signal generator 31g into an analog signal. The output of the D / A converter 31c is connected to the input of the amplifier 31a. The amplifier 31a amplifies the analog signal from the D / A converter 31c to generate the source high frequency power HF. The gain of the amplifier 31a is specified to the high frequency power supply 31 by the control unit 2. Note that the high frequency power supply 31 does not need to include the D / A converter 31c. In this case, the output of the signal generator 31g is connected to the input of the amplifier 31a, and the amplifier 31a amplifies the high frequency signal from the signal generator 31g to generate the source high frequency power HF.

[0026] The bias power supply 32 is electrically coupled to the substrate support 11. The bias power supply 32 is electrically connected to a bias electrode in the substrate support 11 and is configured to supply an electric bias EB to the bias electrode. The bias electrode may be at least one electrode provided in the conductive member or ceramic member 1111 a of the base 1110. The bias electrode may be common to the radio frequency electrode. When the electric bias EB is supplied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0027] 2 and 3. FIG. 3 is a diagram showing an example of the waveform of the electrical bias. The bias power supply 32 generates a waveform having a period C Ｗ The bias electrode is configured to periodically apply an electric bias EB having a waveform period C Ｗ A plurality of waveform periods C Ｗ is applied to the bias electrode at each of the waveform periods C Ｗ is the bias frequency f ＥＢ The bias frequency f ＥＢ is a frequency of, for example, 50 kHz or more and 27 MHz or less. Ｗ The time length is the reciprocal of the bias frequency.

[0028] The electric bias EB may be a bias high frequency power LF having a bias frequency. That is, the electric bias EB may have a sinusoidal waveform whose frequency is the bias frequency. In this case, the bias power supply 32 is electrically connected to the bias electrode via a matching box 34. The variable impedance of the matching box 34 is set to reduce reflection of the bias high frequency power LF from the load.

[0029] Alternatively, the electrical bias EB may include a voltage pulse VP. The voltage pulse VP has a waveform period C Ｗ The voltage pulse VP is applied to the bias electrode within a waveform period C Ｗ The voltage pulse VP is periodically applied to the bias electrode at a time interval equal to the time length of the voltage pulse VP. The waveform of the voltage pulse VP may be a square wave, a triangular wave, or any other waveform. The polarity of the voltage of the voltage pulse VP is set so as to generate a potential difference between the substrate W and the plasma, thereby attracting ions from the plasma to the substrate W. The voltage pulse VP has a waveform period C during which the potential of the substrate W is negative. Ｗ is applied to the bias electrode so as to include the voltage pulse VP. The voltage pulse VP applied to the bias electrode may have a negative potential, a positive potential, or a potential that changes between a positive potential and a negative potential. The voltage pulse VP may be a negative voltage pulse or a negative DC voltage pulse. Note that when the electric bias EB is a voltage pulse VP, the plasma processing apparatus 1 does not need to be equipped with the matching unit 34.

[0030] As shown in FIG. 2 , the plasma processing apparatus 1 may further include a sensor 35 and / or a sensor 36. The sensor 35 is configured to measure the power level Pr of the source high frequency power HF reflected from the load. The sensor 35 includes, for example, a directional coupler. The directional coupler may be provided between the high frequency power supply 31 and the matching device 33. The sensor 35 may further measure the power level Pf of the forward wave of the source high frequency power HF. The power level Pr of the reflected wave measured by the sensor 35 is notified to the high frequency power supply 31. In addition, the power level Pf of the forward wave may be notified from the sensor 35 to the high frequency power supply 31. The sensor 35 may notify the high frequency power supply 31 of the reflectivity, i.e., Pr / Pf. The reflectivity may be determined from the power levels Pf and Pr in the high frequency power supply 31. Note that a detection circuit 35b may be connected between the sensor 35 and the high frequency power supply 31, and the power levels Pf and Pr may be determined from the output of the detection circuit 35b.

[0031] The sensor 36 includes a voltage sensor and a current sensor. The sensor 36 detects a voltage V in a power supply line connecting the high frequency power supply 31 and the high frequency electrode. Ｓ and current I Ｓ The source high frequency power HF is supplied to the high frequency electrode via this power supply line. The sensor 36 may be provided between the high frequency power supply 31 and the matching box 33. The voltage V Ｓ and current I Ｓ is notified to the high frequency power supply 31. The sensor 36 detects the voltage V Ｓ and current I Ｓ The impedance Z of the load of the high frequency power supply 31 determined from Ｌ The high frequency power supply 31 may be notified of the impedance Z Ｌ is the voltage V Ｓ and current I Ｓ The sensor 36 may be determined from the voltage V Ｓ and current I Ｓ The phase difference θ between the voltage V Ｓ and current I ＳThe sensor 36 may be determined from the voltage V Ｓ and current I Ｓ The reflection coefficient Γ determined from the voltage V Ｓ and current I Ｓ It may be identified from

[0032] The DC power supply 38 is configured to apply a DC voltage DCS to the upper electrode. The DC power supply 38 may apply a negative DC voltage to the upper electrode. The DC power supply 38 may be a variable DC power supply.

[0033] 2 and 3, reference will now be made to FIGS. 4 to 17. Each of FIGS. 4 to 17 is an example timing chart related to a power supply system according to an exemplary embodiment. Each of FIGS. 4 to 17 shows the power level of the source high frequency power HF and the level of the electric bias EB. In each of FIGS. 4 to 17, "ON" for the electric bias EB indicates that the electric bias EB is being supplied, and "OFF" for the electric bias EB indicates that the supply of the electric bias EB is stopped. In each of FIGS. 4 to 17, "HIGH" for the electric bias EB indicates that an electric bias EB having a level higher than the level indicated by "LOW" is being supplied. Note that when the electric bias EB is the bias high frequency power LF, the level of the electric bias EB is the power level of the bias high frequency power LF. When the electric bias EB includes a voltage pulse VP, the electric bias EB has a higher level as the energy of ions attracted to the substrate W increases. When the electric bias EB includes a voltage pulse VP, the level of the electric bias EB may be the absolute value of the negative voltage level of the voltage pulse VP relative to a reference voltage (for example, 0 V). ＶＰ is further shown. ＶＰ is the waveform period C Ｗ 15, the bias frequency f ＥＢis further shown. Also, in Figures 16 and 17, a DC voltage DCS is further shown. In each of Figures 16 and 17, "ON" for the DC voltage DCS indicates that the DC voltage DCS is being supplied, and "OFF" for the DC voltage DCS indicates that the supply of the DC voltage DCS is stopped. In each of Figures 16 and 17, "HIGH" for the DC voltage DCS indicates that a DC voltage DCS having a level higher than the level indicated by "LOW" is being supplied. Note that the level of the DC voltage DCS may be the absolute value of the voltage level of the DC voltage DCS in the negative direction relative to its reference voltage level (e.g., 0 V).

[0034] As shown in Figures 4 to 17, the power level of the source high frequency power HF from the high frequency power supply 31 is modulated. The power level of the source high frequency power HF from the high frequency power supply 31 is specified by a power supply control unit. As shown in Figures 4 to 17, the power supply control unit controls the modulation period C Ｍ is repeated to periodically modulate the power level of the source high frequency power HF. The power supply control unit may be provided inside the high frequency power supply 31 or may be provided outside the high frequency power supply 31. The signal generator 31g may function as the power supply control unit, or another device inside the high frequency power supply 31 may function as the power supply control unit. Alternatively, the control unit 2 may function as the power supply control unit.

[0035] As shown in FIGS. 4 to 17, the power supply control unit 100 controls the modulation period C Ｍ The power supply control unit may be configured to periodically modulate the conditions of the electric bias EB in a repetition of the modulation cycle C Ｍ As shown in FIG. 14, the power supply control unit may periodically modulate the level of the electric bias EB by repeating the modulation cycle C Ｍ In the repetition of ＶＰ As shown in FIG. 15 , the power supply control unit may periodically modulate the modulation period C Ｍ In the repetition of the bias frequency f ＥＢ Furthermore, the power supply control unit may periodically modulate the modulation period C ＭThe voltage level of the DC voltage DCS may be periodically modulated in the repetition of the above.

[0036] As shown in FIGS. 4 to 17, the modulation period C Ｍ is a number of sub-periods P Ｓ In these figures, P Ｓ The number in parentheses following is the modulation period C Ｍ Sub-period P Ｓ As shown in FIGS. 4 to 17, the modulation period C Ｍ is at least two sub-periods P in which the power level of the source high frequency power HF is set to a level greater than zero and different from each other. Ｓ In the examples shown in FIGS. 4 to 15, a plurality of sub-periods P Ｓ Each of the sub-periods P is a period during which the power level of the source high frequency power HF and the conditions of the electric bias EB remain the same. Ｓ Each of the periods is a period during which the power level of the source high frequency power HF, the condition of the electric bias EB, and the output voltage level of the DC power supply 38 (i.e., the voltage level of the DC voltage DCS) remain the same.

[0037] Multiple sub-periods P Ｓ Each of the feedback periods P Ｆ [1] (first feedback period). As shown in FIGS. 4 to 12, a plurality of sub-periods P Ｓ Each of these is a feedback period P Ｆ The remaining period following [1] is the feedback period P Ｆ [2] (second feedback period). Alternatively, multiple sub-periods P Ｓ At least one sub-period of the feedback period P Ｆ [1] may be included. That is, multiple sub-periods P Ｓ At least one sub-period of the feedback period P Ｆ In the example shown in FIG. Ｓ [1] is the feedback period PＦ [1]. Alternatively, multiple sub-periods P Ｓ Each of these is a feedback period P Ｆ [1] may be included. That is, multiple sub-periods P Ｓ Each of these is a feedback period P Ｆ It may be consistent with [1].

[0038] The high frequency power supply 31 has a modulation period C in order to suppress reflection of the source high frequency power HF from the load. Ｍ Each phase period P Ｈ The source frequency f is adjusted for the high frequency power supply 31. The source frequency f is specified by the power supply control unit to the high frequency power supply 31. Adjustment of the source frequency f will be described below with reference to FIGS. 2 to 17 as well as FIGS. 18(a) and 18(b). FIG. 18(a) is a flowchart of a control method according to one exemplary embodiment, and FIG. 18(b) is a flowchart of step STa shown in FIG. 18(a). In the control method shown in FIG. 18(a) (hereinafter referred to as "method MT"), each component of the power supply system 30 is controlled by the power supply control unit.

[0039] 18A, the method MT includes steps STa and STb. In step STa, a source high frequency power HF is supplied from the high frequency power supply 31 to a high frequency electrode to generate plasma in the chamber 10 of the plasma processing apparatus 1. In step STb, a waveform period C is set to 0.5 to 1.5 to 2.5 to 3.5 in order to attract ions from the plasma to the substrate W on the substrate support 11. Ｗ An electric bias EB is supplied to the substrate support 11 (i.e., the bias electrode) repeatedly at time intervals of .

[0040] As shown in (b) of Fig. 18, the process STa includes a process STc and a process STd. In the process STc, as in the examples of Figs. 4 to 17, the modulation period C Ｍ The power level of the source high frequency power HF is periodically modulated by repeating the above steps. Ｍ The level of the electric bias EB may be periodically modulated in the repetition of the modulation period C ＭThe level of the DC voltage DCS may be periodically modulated in the repetition of the above.

[0041] In step STd, each modulation period C Ｍ Each phase period P Ｈ The source frequency f for the modulation period C is adjusted to suppress the degree of reflection of the source high frequency power HF. The process in step STd will be described in more detail below. Ｍ [y] is the modulation period C Ｍ The y-th modulation period C in the repetition of Ｍ represents the phase period P Ｈ [k] is the modulation period C Ｍ represents the k-th phase period in the phase period P Ｈ [j] is the waveform period C Ｗ represents the j-th phase period in the waveform period C Ｗ [m] is the feedback period P Ｆ [1] and the feedback period P Ｆ [2] Ｗ Represents.

[0042] <First modulation period ~ Y １ Setting the source frequency in the modulation period >

[0043] Modulation period C Ｍ [1] ~ Modulation period C Ｍ [Y １ ] in each feedback period P Ｆ Phase period P in [1] Ｈ In [k], the frequency prepared in advance for that phase period is used as the source frequency f. Alternatively, the modulation period C Ｍ [1] ~ Modulation period C Ｍ [Y １ ] in each of the feedback periods P Ｆ Waveform period C in [1] Ｗ A number of phase periods P in [m] Ｈ In the case of "Y", a plurality of frequencies included in a frequency set prepared in advance for the waveform period are used as the source frequency f. １ " is an integer greater than or equal to 1, for example, 5.

[0044] Modulation period C Ｍ [1] ~ Modulation period C Ｍ [Y １ ] in each of the feedback periods P Ｆ Waveform period C in [2] Ｗ A number of phase periods P in [m] Ｈ In each of the modulation periods C, a frequency determined by a second feedback, which will be described later, may be used as the source frequency f. Ｍ [1] ~ Modulation period C Ｍ [Y １ ] in each of the feedback periods P Ｆ [2] Multiple waveform periods C Ｗ A plurality of phase periods P within each of Ｈ So, the previous feedback period P Ｆ The final waveform period C in [1] Ｗ A plurality of phase periods P Ｈ Each of the multiple source frequencies f used in may be used.

[0045] <Y ２ Setting the source frequency for modulation periods from the th modulation period onwards>

[0046] Y ２ th modulation period C Ｍ [Y ２ ] and each subsequent modulation period C Ｍ Feedback period P Ｆ Phase period P in [1] Ｈ In [k], the frequency determined by the first feedback, which will be described later, is used as the source frequency f. Alternatively, the modulation period C Ｍ [Y ２ ] and each subsequent modulation period C Ｍ Feedback period P Ｆ Waveform period C in [1] Ｗ A number of phase periods P in [m] Ｈ In each of the first and second inputs, a frequency determined by a first feedback, which will be described later, is used as the source frequency f.

[0047] Modulation period C Ｍ [Y ２ ] and each subsequent modulation period C ＭFeedback period P Ｆ Waveform period C in [2] Ｗ A number of phase periods P in [m] Ｈ In each of the modulation periods C, a frequency determined by a second feedback, which will be described later, may be used as the source frequency f. Ｍ [Y ２ ] and each subsequent modulation period C Ｍ Feedback period P Ｆ [2] Multiple waveform periods C Ｗ A plurality of phase periods P within each of Ｈ So, the previous feedback period P Ｆ The final waveform period C in [1] Ｗ A plurality of phase periods P Ｈ Each of the multiple source frequencies f used in may be used.

[0048] In addition, "Y ２ " is Y １ +1. Alternatively, the modulation period C Ｍ [Y １ ] to modulation period C Ｍ [Y ２ ]. The delay time may be on the order of several seconds. When the delay time is provided, the modulation period C Ｍ [Y １ ], immediately after the modulation period C Ｍ [Y ２ ] each modulation period C Ｍ A plurality of phase periods P Ｈ The source frequency of the modulation period C Ｍ [Y １ ] in a plurality of phase periods P Ｈ The multiple source frequencies f used in may be used respectively.

[0049] The first feedback and the second feedback will be described below with reference to Fig. 19 and Fig. 20. Fig. 19 is a flowchart showing an example of the process in step STd shown in Fig. 18(b). Fig. 20 is a flowchart showing an example of the process in step ST7 shown in Fig. 19.

[0050] In the first feedback, the modulation period CＭ Repeating the modulation cycle C Ｍ is a periodic series C Ｓ In the second feedback, the modulation period C Ｍ Feedback period P in [y] Ｆ [2] Multiple waveform periods C Ｗ and its feedback period P Ｆ I immediately before [2] ｒｅｆ Waveform period C Ｗ is a periodic series C Ｓ In the first feedback, the modulation period C Ｍ Phase period P Ｈ The source frequency f of [k] is Ｍ Phase period P in the series Ｈ The second feedback is determined based on the change in the source frequency f of [k] and the change in the degree of reflection of the source high frequency power HF, so as to suppress the degree of reflection. Ｍ Feedback period P in [y] Ｆ Waveform period C in [2] Ｗ Phase period P in [m] Ｈ The source frequency f of [j] is Ｆ [2] The preceding waveform periods C Ｗ Phase period P in the series Ｈ The source frequency f is determined by the power supply control unit in each of the first feedback and the second feedback based on the change in the source frequency f of [j] and the change in the degree of reflection of the source high frequency power HF so as to suppress the degree of reflection.

[0051] Hereinafter, the modulation period C in the first feedback Ｍ Phase period P in the series Ｈ [k] and the waveform period C in the second feedback Ｗ Phase period P in the series Ｈ Each of [j] is expressed as a periodic sequence C Ｓ Phase period P Ｈ [n]. Also, the modulation period C Ｍ and the waveform period C in the second feedbackＷ Each of these is a period C Ｒ Refer to it as.

[0052] 19, the process STd may include processes ST1 to ST7. The processes ST1 to ST7 are performed by the cyclic sequence C Ｓ Each period C Ｒ Each phase period P Ｈ This is done for.

[0053] In step ST1, the power supply control unit changes i to I ｉｎｉ -I ｒｅｆ "i" is set to the periodic sequence C Ｓ Period C included in Ｒ In the first feedback, "I ｉｎｉ " is initially the above-mentioned "Y ２ In the first feedback, ｉｎｉ -I ｒｅｆ " is a periodic sequence C Ｓ I included in ｉｎｉ th period C Ｒ The previous cycle C Ｒ It represents the order of ｒｅｆ " is 1. Also, in the second feedback, "I ｉｎｉ " is initially "1". In the second feedback, "I ｉｎｉ -I ｒｅｆ " is a periodic sequence C Ｓ I included in ｉｎｉ th period C Ｒ I ｒｅｆ Previous cycle C Ｒ It represents the order of ｒｅｆ " is an integer equal to or greater than 1. In the second feedback, "I ｒｅｆ " may be 1, 2, or an integer greater than 2. In the second feedback, I ｒｅｆ If is 2 or more, each phase period P in the second feedback Ｈ Therefore, a relatively long processing time is ensured for determining the source frequency.

[0054] In the subsequent step ST2, the power supply control unit calculates the degree of reflection Pｄ It is determined whether [i, n] is large enough to satisfy the frequency change condition. ｄ [i, n] is a periodic sequence C Ｓ The i-th period C included in Ｒ Phase period P in [i] Ｈ In step ST2, the frequency change condition is the reflection degree P ｄ In step ST2, the frequency change condition is satisfied when [i, n] is greater than the threshold value. ｄ [i, n] is the first threshold P ｔｈ１ [n]. Ｈ The first threshold P for each ｔｈ１ may be the same as or different from each other.

[0055] If it is determined in step ST2 that the frequency change condition is satisfied, the power supply control unit changes the source frequency f[i+I ｒｅｆ , n] is set by equation (1). ｒｅｆ , n]=f[i, n]+Δf[i, n] (1) where f[i, n] is the periodic sequence C Ｓ The i-th period C included in Ｒ Phase period P in [i] Ｈ [n] represents the source frequency f, and Δf[i,n] is a shift value, the initial value of which is set in advance.

[0056] On the other hand, if it is determined in step ST2 that the frequency change condition is not satisfied, the power supply control unit changes the source frequency f[i+I ｒｅｆ , n] is set by equation (2). ｒｅｆ ,n]=f[i,n]...(2)

[0057] Next, steps ST5 to ST7 are performed. Steps ST5 to ST7 are repeated until an instruction to end the steps is given. Step ST5 includes steps ST5a, ST5b, and ST5c. In step ST5a, I ｒｅｆ It is determined whether I is greater than 1. ｒｅｆIf I is 1, the process proceeds to step ST5c. ｒｅｆ If f[i+h, n] is greater than 1, in step ST5b, the power supply control unit sets f[i+h, n] to f[i, n]. ｒｅｆ The process is continued while incrementing the value by 1 up to -1. Then, the process proceeds to step ST5c.

[0058] In step ST5c, the power supply control unit changes i to 1+I ｒｅｆ In the next step ST6, the power supply control unit increments the periodic sequence C Ｓ Period C in Ｒ Phase period P in [i] Ｈ At [n], a source high frequency power HF having a source frequency f[i,n] is supplied from a high frequency power supply 31 .

[0059] In the subsequent step ST7, the power supply control unit calculates the degree of reflection P ｄ Depending on [i, n], a periodic sequence C Ｓ Later period C in Ｒ [i+I ｒｅｆ ] within the phase period P Ｈ Source frequency f[i+I ｒｅｆ , n] is determined.

[0060] 20, the process ST7 starts with a process ST701. In the process ST701, the power supply control unit calculates the degree of reflection P ｄ In step ST701, it is determined whether the reflection degree P ｄ [i, n] is P ｄ [i, n]>P ｄ [i-I ｒｅｆ , n] is satisfied, it may be determined that there is an increasing trend. Ｓ The i-th period C in Ｒ X cycles C up to [i] Ｒ over the phase period P Ｈ When the degree of reflection in [n] tends to increase, the degree of reflection P ｄ It may be determined that [i, n] is on an increasing trend. Here, "X" is an integer equal to or greater than 2. Ｓ The i-th period C in ＲX cycles C up to [i] Ｒ is C Ｒ [i-x x I ｒｅｆ ], where "x" is an integer between 0 and (X-1).

[0061] In step ST701, the degree of reflection P ｄ If it is determined that [i, n] is not on an increasing trend, the power supply control unit maintains the sign of the shift value Δf[i, n] in step ST702. That is, the power supply control unit sets the shift value Δf[i, n] according to equation (3) in step ST702. Δf[i, n]=Δf[i-I ｒｅｆ , n] ... (3)

[0062] On the other hand, in step ST701, the degree of reflection P ｄ If it is determined that [i, n] is on the increase, the power supply control unit changes the sign of the shift value Δf[i, n] in step ST703. That is, in step ST703, the power supply control unit sets the shift value Δf[i, n] according to equation (4). Δf[i, n]=-Δf[i-I ｒｅｆ , n] ... (4)

[0063] In the next step ST704, the power supply control unit determines whether or not a shift direction change condition is satisfied. The shift direction change condition is a combination of the source frequency f[i, n] and the period C Ｒ The (nu)th phase period P in [i] Ｈ The absolute value of the difference between the source frequency f[i, n] and the source frequency f[i, n] and the period C Ｒ The (n+u)th phase period P in [i] ＨThe shift direction change condition is satisfied when, as a result of comparing each of the absolute values ​​of the difference between source frequency f[i,n] and source frequency f[i,n+u] with a predetermined value, it is determined that the change in source frequency is large, and both source frequency f[i,n-u] and source frequency f[i,n+u] are greater than or smaller than source frequency f[i,n]. For example, the shift direction change condition is satisfied when each of the absolute value of the difference between source frequency f[i,n] and source frequency f[i,n-u] and the absolute value of the difference between source frequency f[i,n] and source frequency f[i,n+u] are greater than a predetermined value, and both source frequency f[i,n-u] and source frequency f[i,n+u] are greater than or smaller than source frequency f[i,n].

[0064] In step ST704, u may be 1 or a numerical value greater than 1. Alternatively, in step ST704, the shift direction change condition may be satisfied when u is any numerical value within a range of 1 to a numerical value greater than 1.

[0065] If it is determined in step ST704 that the shift direction change condition is satisfied, the power supply control unit changes the sign of the shift value Δf[i,n] in step ST705. That is, in step ST705, the power supply control unit sets the shift value Δf[i,n] according to equation (5). Δf[i,n]=|Δf[i-I ｒｅｆ , n] | * sign(f[i, n] - f[i, n - u]) ... (5) where sign() is a function that returns the sign of the number in parentheses. Also, u is the value of u when the shift direction change condition is satisfied.

[0066] On the other hand, if it is determined in step ST704 that the shift direction change condition is not satisfied, the power supply control unit maintains the sign of the shift value Δf[i,n] in step ST706. That is, in step ST706, the power supply control unit sets the shift value Δf[i,n] according to equation (6). Δf[i,n]=Δf[i,n] (6)

[0067] In the subsequent step ST707, the power supply control unit Ｓ Period C in Ｒ Phase period P in [i] ＨThe degree of reflection of the source high frequency power HF in [n] P ｄ In step ST707, it is determined whether [i, n] is large enough to satisfy the frequency change condition. Ｓ Period C in Ｒ Phase period P in [i] Ｈ The degree of reflection of the source high frequency power HF in [n] P ｄ Satisfied if [i, n] is greater than a threshold.

[0068] If it is determined in step ST707 that the frequency change condition is satisfied, the power supply control unit 100 changes the periodic sequence C Ｓ Later period C in Ｒ [i+I ｒｅｆ ] within the phase period P Ｈ Source frequency f[i+I ｒｅｆ , n] is set by equation (7). ｒｅｆ ,n]=f[i,n]+Δf[i,n]...(7)

[0069] On the other hand, if the frequency change condition is not satisfied in step ST707, the power supply control unit changes the source frequency f[i+I ｒｅｆ , n] is set by equation (8). ｒｅｆ ,n]=f[i,n]...(8)

[0070] In one embodiment, the periodic sequence C Ｓ Any period C in Ｒ Phase period P Ｈ The degree of reflection at [n] and the first threshold P ｔｈ１ If it is determined that the degree of reflection is small as a result of the comparison between the period [n] and the period C in step ST707, Ｒ Phase period P Ｈ The degree of reflection at [n] and the second threshold P ｔｈ２ The frequency change condition may not be satisfied in step ST707 until it is determined that the degree of reflection is large as a result of the comparison with the second threshold value P ｔｈ２ [n] is the first threshold P ｔｈ１The second threshold P ｔｈ２ [n] is the first threshold P ｔｈ１ [n]. Note that the number of phase periods P Ｈ [n] the second threshold P for each ｔｈ２ [n] may be the same or different.

[0071] Specifically, the periodic sequence C Ｓ Any period C in Ｒ Phase period P Ｈ The degree of reflection at [n] is equal to or exceeds the first threshold value P ｔｈ１ If it is determined that the phase period P Ｈ A second threshold P is used as a threshold to be compared with the degree of reflection at [n]. ｔｈ２ [n] may be used. Ｓ Phase period P in any waveform period Ｈ The degree of reflection at [n] is equal to or exceeds the second threshold value P ｔｈ２ If it is determined that the phase period P Ｈ A first threshold P is used as a threshold to be compared with the degree of reflection at [n]. ｔｈ１ [n] may also be used.

[0072] In the method MT, the degree of reflection P ｄ [i, n] depending on the source frequency f[i+I ｒｅｆ , n], the reflection of the source high frequency power HF is suppressed. Also, when the shift direction change condition is satisfied, that is, when each period C Ｒ If a large source frequency variation can occur within a period C that results in a large source frequency increase or decrease followed by a large source frequency decrease or increase, the sign of the shift value is changed. Ｒ As described above, the first threshold P ｔｈ１ and the second threshold P ｔｈ２By using the method MT, excessive changes in the source frequency are prevented. Furthermore, when the method MT is repeated, high reproducibility of the time change in the source frequency can be achieved. Note that step ST7 shown in FIG. 20 does not necessarily include steps ST704 to ST706.

[0073] Another example of the process in step STd will be described below with reference to Figures 21 and 22. Figure 21 is a flowchart showing another example of the process in step STd shown in Figure 18(b). Figure 22 is a flowchart showing an example of the process in step ST7a shown in Figure 21. The process in step STd shown in Figures 21 and 22 will be described below from the perspective of differences from the process shown in Figures 19 and 20. In the process shown in Figures 21 and 22, the power supply control unit calculates the shift value Δf[i,n] as the degree of reflection P ｄ It is set to a value according to the magnitude of [i, n].

[0074] 21, the power supply control unit sets the source frequency f[i,n] and the coefficient α[i,n] in the steps between process ST1 and process ST3. In the steps between process ST1 and process ST3, the source frequency f[i,n] and the coefficient α[i,n], i.e., the source frequency f[1,n] and the coefficient α[1,n], are initially set to respective values ​​that are set in advance.

[0075] If it is determined in step ST2 that the frequency change condition is satisfied, the power supply control unit sets the shift value Δf[i, n] according to equation (9) in step ST3a between step ST2 and step ST3. Δf[i, n]=α[i, n]*(P ｄ [i,n]-P ｔｈ１ [n]) (9) Here, the coefficient α[1, n] is a preset value.

[0076] Then, in step ST7a following step ST6, the power supply control unit calculates the degree of reflection P ｄ Depending on [i, n], a periodic sequence C Ｓ Later period C in Ｒ [i+I ｒｅｆ ] within the phase period P Ｈ Source frequency f[i+I ｒｅｆ, n] is determined.

[0077] As shown in Fig. 22, the process ST7a starts with a step ST701. ｄ If it is determined that [i, n] is not increasing, the power supply control unit maintains the sign of the coefficient α[i, n] in step ST702a. That is, the power supply control unit sets the coefficient α[i, n] according to equation (10) in step ST702a. α[i, n] = α[i - I ｒｅｆ , n] ... (10)

[0078] On the other hand, in step ST701, the degree of reflection P ｄ If it is determined that [i, n] is on the increase, the power supply control unit changes the sign of the coefficient α[i, n] in step ST703a. That is, in step ST703a, the power supply control unit sets the coefficient α[i, n] according to equation (11): α[i, n]=-α[i-I ｒｅｆ , n] ... (11)

[0079] 22, if it is determined in step ST704 that the shift direction change condition is satisfied, the power supply control unit changes the sign of the coefficient α[i,n] in step ST705a. That is, in step ST705a, the power supply control unit sets the coefficient α[i,n] according to equation (12). α[i,n]=|α[i-I ｒｅｆ , n]|*sign(f[i, n]-f[i, n-u]) (12) where u is the value of u when the shift direction change condition is satisfied.

[0080] On the other hand, if it is determined in step ST704 that the shift direction change condition is not satisfied, the power supply control unit maintains the sign of the coefficient α[i,n] in step ST706a. That is, in step ST706a, the power supply control unit sets the coefficient α[i,n] according to equation (13). α[i,n]=α[i,n] (13)

[0081] As shown in FIG. 22, if it is determined in step ST707 that the frequency change condition is satisfied, in step ST708a between step ST707 and step ST708, the power supply control unit sets the shift value Δf[i,n] by equation (14). Δf[i,n]=α[i,n]*(P ｄ [i,n]-P ｔｈ１ [n]) …(14)

[0082] In the example of FIG. 22, the periodic sequence C Ｓ Any period C in Ｒ Phase period P Ｈ The degree of reflection at [n] and the first threshold P ｔｈ１ If it is determined that the degree of reflection is small as a result of the comparison between the period [n] and the period C in step ST707, Ｒ Phase period P Ｈ The degree of reflection at [n] and the second threshold P ｔｈ２ The frequency change condition may not be satisfied in step ST707 until it is determined that the degree of reflection is large as a result of the comparison with the second threshold value P ｔｈ２ [n] is the first threshold P ｔｈ１ The second threshold P ｔｈ２ [n] is the first threshold P ｔｈ１ [n]. Note that the number of phase periods P Ｈ [n] the second threshold P for each ｔｈ２ [n] may be the same or different.

[0083] Specifically, the periodic sequence C Ｓ Any period C in Ｒ Phase period P Ｈ The degree of reflection at [n] is equal to or exceeds the first threshold value P ｔｈ１ If it is determined that the phase period P Ｈ A second threshold P is used as a threshold to be compared with the degree of reflection at [n]. ｔｈ２ [n] may be used. Ｓ Phase period P in any waveform period ＨThe degree of reflection at [n] is equal to or exceeds the second threshold value P ｔｈ２ If it is determined that the phase period P Ｈ A first threshold P is used as a threshold to be compared with the degree of reflection at [n]. ｔｈ１ [n] may be used. Note that the process ST7a shown in FIG. 22 does not necessarily include the process ST704, the process ST705a, and the process ST706a.

[0084] Below, the degree of reflection P ｄ [i, n] will be explained. The degree of reflection P ｄ [i, n] is a periodic sequence C Ｓ Phase period P within period CR[i] Ｈ The phase period P is obtained by obtaining a plurality of evaluation values ​​at each of a plurality of sample times in [n]. The plurality of evaluation values ​​reflect the magnitude of the reflection of the source high frequency power HF at each of the plurality of sample times. Ｈ The number of sample time points in each may be the same.

[0085] Degree of reflection P ｄ [i, n] is a periodic sequence C Ｓ Phase period P within period CR[i] Ｈ The representative value is a representative value of the evaluation values ​​at each of the multiple sample points in time [n]. The representative value may be an average value of the multiple evaluation values, a weighted average value of the multiple evaluation values, or a maximum value of the multiple evaluation values. Each of the multiple evaluation values ​​may be a power level Pr of the reflected wave, a reflectivity (i.e., Pr / Pf), an impedance Z, etc., as measured values ​​acquired by the sensors 35 and 36. Ｌ and the characteristic impedance, or the reflection coefficient Γ. Each of the plurality of evaluation values ​​may be the difference between the resistance value of the input of the matching box 33 (i.e., the input of the matching box 33 on the high frequency power source 31 side) or the transmission system of the source high frequency power HF as seen from the high frequency power source 31 and a predetermined resistance value (50Ω, etc.). Alternatively, each of the plurality of evaluation values ​​may be the voltage V at the input of the transmission system of the source high frequency power HF or the matching box. Ｓ and current I Ｓ and a predetermined value (such as 90 degrees).

[0086] In one embodiment, the degree of reflection P ｄ [i, n] is a periodic sequence C Ｓ Phase period P within period CR[i] Ｈ The weighted average of the evaluation values ​​at each of the multiple sample points in [n] is calculated by multiplying the evaluation values ​​by a window function to calculate the average of multiple values. The window function is used for the phase period P Ｈ The weight decreases according to the time difference from the center of [n]. As the window function, a triangular window, a Gaussian window, a Hanning window, a Hamming window, or the like is used. According to the weighted average value using such a window function, each phase period P Ｈ The degree of reflection P that may occur due to the phase of the source high frequency power HF at ｄ It is possible to suppress the variation in the calculated values ​​of [i, n].

[0087] Reference is now made to Figure 23, which is a timing chart relating to a power supply system according to one exemplary embodiment. The high frequency power supply 31 generates a waveform having a period C Ｗ Alternatively, the high frequency power supply 31 may supply the source high frequency power HF continuously for the entire period of the waveform cycle C. Ｗ That is, the high frequency power source 31 may pulse the source high frequency power HF within a waveform period C Ｗ Pulses of high frequency power HF may be supplied from the source within the chamber.

[0088] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0089] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E10] below.

[0090] a power supply controller configured to periodically modulate a power level of the source radio frequency power in repetition of a modulation period, the modulation period including a plurality of sub-periods, the plurality of sub-periods including at least two sub-periods in which the power level of the source radio frequency power is set to a power level greater than zero and different from each other, each of the at least two sub-periods including a feedback period extending from a start point of the modulation period, and the power supply controller configured to adjust a source frequency of the source radio frequency power for a kth phase period in the modulation period included in the feedback period based on a change in the source frequency and a change in a degree of reflection of the source radio frequency power in the kth phase period in a previous repetition of the modulation period, so as to suppress the degree of reflection of the source radio frequency power.

[0091] [E2] The plasma processing apparatus according to E1, wherein the power supply system is configured to maintain the same power level of the source high frequency power and the same conditions of the electrical bias during each of the plurality of sub-periods.

[0092] [E3] The plasma processing apparatus according to E1, wherein the power supply system further includes a DC power supply electrically connected to an upper electrode disposed above the substrate support, and the power supply system is configured to maintain the same settings for the power level of the source radio frequency power, the condition of the electrical bias, and the output voltage level of the DC power supply during each of the plurality of sub-periods.

[0093] [E4] The plasma processing apparatus according to E2 or E3, wherein the electric bias includes a voltage pulse generated periodically at a time interval of the waveform period, and the conditions of the electric bias include at least one selected from the group consisting of a voltage level of the voltage pulse, a duty ratio of the voltage pulse, and a bias frequency that is the reciprocal of the time length of the waveform period.

[0094] [E5] The plasma processing apparatus according to E2 or E3, wherein the electric bias is a bias high frequency power having a bias frequency that is the reciprocal of the time length of the waveform period, and the conditions of the electric bias include at least one selected from the group consisting of a power level of the bias high frequency power and the bias frequency.

[0095] [E6] The plasma processing apparatus according to any one of E1 to E5, wherein the feedback period is a first feedback period, each of the at least two sub-periods includes a second feedback period following the first feedback period, and the power supply control unit is configured to control the high frequency power supply so as to repeatedly use, in the second feedback period, the sequence of source frequencies used in the waveform cycle immediately before the second feedback period.

[0096] [E7] The plasma processing apparatus of any one of E1 to E5, wherein the feedback period is a first feedback period, each of the at least two sub-periods includes a second feedback period following the first feedback period, and the power supply control unit is configured to adjust the source frequency for a jth phase period in each waveform period in the second feedback period of each of the at least two sub-periods based on a change in the source frequency and a change in the degree of reflection of the source high frequency power in the jth phase period in a repetition of the waveform period preceding each of the at least two sub-periods, so as to suppress the degree of reflection of the source high frequency power.

[0097] [E8] The plasma processing apparatus according to any one of E1 to E5, wherein the length of each of the at least two sub-periods is equal to the length of the feedback period.

[0098] [E9] A power supply system comprising: a radio frequency power supply configured to supply source radio frequency power to generate plasma in a chamber of a plasma processing apparatus; a bias power supply configured to repeatedly supply an electrical bias to a substrate support provided in the chamber at a time interval of a waveform period to attract ions from the plasma to a substrate on the substrate support; and a power supply control unit, wherein the power supply control unit is configured to periodically modulate the power level of the source radio frequency power in repetition of a modulation period, the modulation period including a plurality of sub-periods, each of the plurality of sub-periods including at least two sub-periods in which the power level of the source radio frequency power is set to a level greater than zero and different from each other, and each of the at least two sub-periods including a feedback period continuing from a start point of the at least two sub-periods, and the power supply control unit is configured to adjust the source frequency of the source radio frequency power for a kth phase period in the modulation period included in the feedback period based on a change in the source frequency and a change in the degree of reflection of the source radio frequency power in the kth phase period in a previous repetition of the modulation period, so as to suppress the degree of reflection of the source radio frequency power.

[0099] [E10] A method comprising: (a) supplying a source radio frequency power from a radio frequency power source to generate a plasma in a chamber of a plasma processing apparatus; and (b) repeatedly supplying an electrical bias to a substrate support disposed in the chamber at a time interval of a waveform period to attract ions from the plasma to a substrate on the substrate support, wherein (a) comprises: (c) periodically modulating a power level of the source radio frequency power in a repetition of a modulation period, the modulation period including a plurality of sub-periods, the plurality of sub-periods including at least two sub-periods in which the power level of the source radio frequency power is set to a level greater than zero and different from each other, each of the at least two sub-periods including a feedback period continuing from a start point thereof; (d) adjusting a source frequency of the source high frequency power for a kth phase period in the modulation cycle included in the feedback period, the source frequency for the kth phase period in the modulation cycle being adjusted based on a change in the source frequency for the kth phase period in a previous repetition of the modulation cycle and a change in the degree of reflection of the source high frequency power so as to suppress the degree of reflection of the source high frequency power.

[0100] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

[0101] 1... plasma processing apparatus, 10... chamber, 11... substrate support part, 30... power supply system, 31... high frequency power supply, 32... bias power supply

Claims

1. Chamber and, A substrate support portion arranged within the chamber, Power supply system, Equipped with, The aforementioned power supply system is A high-frequency power supply configured to supply high-frequency power in order to generate plasma in the chamber, A bias power supply configured to repeatedly supply an electrical bias to the substrate support portion at time intervals of the waveform period in order to draw ions from the plasma to the substrate on the substrate support portion, Power control unit, Includes, The power control unit is configured to periodically modulate the power level of the high-frequency power during the repetition of the modulation cycle. The modulation period includes a plurality of sub-periods, each of which includes at least two sub-periods in which the power level of the high-frequency power is set to a level greater than zero and to a level different from the others, and each of the at least two sub-periods includes a feedback period that continues from its start. The power control unit is configured to adjust the frequency of the high-frequency power for the k-th phase period within the modulation cycle included in the feedback period, based on the change in the frequency of the high-frequency power in the k-th phase period in the preceding repetition of the modulation cycle, so as to suppress the degree of reflection of the high-frequency power. Plasma processing equipment.

2. The plasma processing apparatus according to claim 1, wherein the power supply system is configured to maintain the same settings for the power level of the high-frequency power and the conditions of the electrical bias during each of the plurality of sub-periods.

3. The power supply system further includes a DC power supply electrically connected to an upper electrode located above the substrate support portion, The power supply system is configured to maintain the same settings for the power level of the high-frequency power, the electrical bias conditions, and the output voltage level of the DC power supply during each of the multiple sub-periods. The plasma processing apparatus according to claim 1.

4. The electrical bias includes voltage pulses that are generated periodically at time intervals of the waveform period. The conditions for the electrical bias include at least one selected from the group consisting of the voltage level of the voltage pulse, the duty cycle of the voltage pulse, and the bias frequency which is the reciprocal of the time length of the waveform period. The plasma processing apparatus according to claim 2 or 3.

5. The electrical bias is a bias high-frequency power having a bias frequency that is the reciprocal of the time length of the waveform period. The conditions for the electrical bias include at least one selected from the group consisting of the power level of the bias high-frequency power and the bias frequency. The plasma processing apparatus according to claim 2 or 3.

6. The aforementioned feedback period is the first feedback period, Each of the two sub-periods includes a second feedback period following the first feedback period. The power supply control unit is configured to control the high-frequency power supply so as to repeatedly use the sequence of frequencies of the high-frequency power used in the waveform period immediately preceding the second feedback period during the second feedback period. A plasma processing apparatus according to any one of claims 1 to 3.

7. The aforementioned feedback period is the first feedback period, Each of the two sub-periods includes a second feedback period following the first feedback period. The power control unit is configured to adjust the frequency of the high-frequency power for the jth phase period within each waveform period in the second feedback period of each of the at least two sub-periods, based on the change in the frequency of the high-frequency power in the jth phase period in the preceding repetition of the waveform period and the change in the degree of reflection of the high-frequency power, so as to suppress the degree of reflection of the high-frequency power. A plasma processing apparatus according to any one of claims 1 to 3.

8. The plasma processing apparatus according to any one of claims 1 to 3, wherein the length of each of the at least two sub-periods is equal to the length of the feedback period.

9. A high-frequency power supply configured to supply high-frequency power for generating plasma in the chamber of a plasma processing apparatus, A bias power supply is configured to repeatedly supply an electrical bias to the substrate support portion at time intervals of the waveform period in order to draw ions from the plasma to the substrate on the substrate support portion provided in the chamber, Power control unit, Equipped with, The power control unit is configured to periodically modulate the power level of the high-frequency power during the repetition of the modulation cycle. The modulation period includes a plurality of sub-periods, each of which includes at least two sub-periods in which the power level of the high-frequency power is set to a level greater than zero and to a level different from the others, and each of the at least two sub-periods includes a feedback period that continues from its start. The power control unit is configured to adjust the frequency of the high-frequency power for the k-th phase period within the modulation cycle included in the feedback period, based on the change in the frequency of the high-frequency power in the k-th phase period in the preceding repetition of the modulation cycle, so as to suppress the degree of reflection of the high-frequency power. Power supply system.

10. The power supply system according to claim 9, wherein the power supply system is configured to maintain the same settings for the power level of the high-frequency power and the conditions of the electrical bias during each of the plurality of sub-periods.

11. Further comprising a DC power supply electrically connected to an upper electrode positioned above the substrate support portion, The power supply system is configured to maintain the same settings for the power level of the high-frequency power, the electrical bias conditions, and the output voltage level of the DC power supply during each of the multiple sub-periods. The power supply system according to claim 9.

12. The electrical bias includes voltage pulses that are generated periodically at time intervals of the waveform period, The conditions for the electrical bias include at least one selected from the group consisting of the voltage level of the voltage pulse, the duty cycle of the voltage pulse, and the bias frequency which is the reciprocal of the time length of the waveform period. The power supply system according to claim 10 or 11.

13. The electrical bias is a bias high-frequency power having a bias frequency that is the reciprocal of the time length of the waveform period, The conditions for the electrical bias include at least one selected from the group consisting of the power level of the bias high-frequency power and the bias frequency. The power supply system according to claim 10 or 11.

14. The feedback period is a first feedback period, Each of the two sub-periods includes a second feedback period following the first feedback period. The power supply control unit is configured to control the high-frequency power supply so as to repeatedly use the sequence of frequencies of the high-frequency power used in the waveform period immediately preceding the second feedback period during the second feedback period. A power supply system according to any one of claims 9 to 11.

15. The feedback period is a first feedback period, Each of the two sub-periods includes a second feedback period following the first feedback period. The power control unit is configured to adjust the frequency of the high-frequency power for the jth phase period within each waveform period in the second feedback period of each of the at least two sub-periods, based on the change in the frequency of the high-frequency power in the jth phase period in the preceding repetition of the waveform period and the change in the degree of reflection of the high-frequency power, so as to suppress the degree of reflection of the high-frequency power. A power supply system according to any one of claims 9 to 11.

16. The power supply system according to any one of claims 9 to 11, wherein the length of each of the at least two sub-periods is equal to the length of the feedback period.

17. (a) A step of supplying high-frequency power from a high-frequency power supply to generate plasma in the chamber of the plasma processing apparatus, (b) A step of repeatedly supplying an electrical bias to the substrate support portion at time intervals of the waveform period in order to draw ions from the plasma to the substrate on the substrate support portion located in the chamber, Includes, The above (a) is, (c) A step of periodically modulating the power level of the high-frequency power in a repeating modulation cycle, wherein the modulation cycle includes a plurality of sub-periods, the plurality of sub-periods including at least two sub-periods in which the power level of the high-frequency power is set to a level greater than zero and different from each other, and each of the at least two sub-periods includes a feedback period that continues from its start, (d) A step of adjusting the frequency of the high-frequency power for the k-th phase period within the modulation cycle included in the feedback period, wherein the frequency of the high-frequency power for the k-th phase period within the modulation cycle is adjusted to suppress the degree of reflection of the high-frequency power, based on the change in the frequency of the high-frequency power for the k-th phase period and the change in the degree of reflection of the high-frequency power in the preceding repetition of the modulation cycle. A control method including

18. A program for causing a plasma processing apparatus to execute the control method described in Claim 17.