Plasma processing apparatus, power supply system, and control method

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

[Technical Field]

[0001] Exemplary embodiments of this disclosure relate to a plasma processing apparatus, a power supply system, and a control method. [Background technology]

[0002] Plasma processing equipment is used in plasma processing of substrates. In plasma processing equipment, bias high-frequency power is used to draw ions from the plasma generated in the chamber onto the substrate. Patent Document 1 below discloses a plasma processing equipment that modulates the power level and frequency of bias high-frequency power. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2009-246091 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure provides a technology for suppressing the reflection of high-frequency power. [Means for solving the problem]

[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 high-frequency power supply, a bias power supply, and a power control unit. The high-frequency power supply is configured to supply high-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, which is located within the chamber, at time intervals of the waveform period, to draw ions from the plasma onto the substrate on the substrate support. The power control unit is configured to periodically modulate the power level of the high-frequency power in repetitions of the modulation period. The modulation period includes a plurality of sub-periods. The plurality of sub-periods include 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 one another. Each of the at least two sub-periods includes a feedback period that follows from its start. The power control unit is configured to adjust the frequency of the high-frequency power for the nth phase period within the modulation cycle included in the feedback period, based on the change in the frequency of the high-frequency power for the nth phase period in the repetition of the preceding modulation cycle and the change in the degree of reflection of the high-frequency power, in order to suppress the degree of reflection of the high-frequency power. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to suppress the reflection of high-frequency power. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram illustrating an example configuration of a plasma processing system. [Figure 2] This is a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus. [Figure 3] This figure shows an example of an electrical bias waveform. [Figure 4] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 5]This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 6] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 7] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 8] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 9] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 10] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 11] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 12] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 13] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 14] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 15] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 16] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 17] This is an example timing chart related to a power supply system according to one exemplary embodiment. [Figure 18] Figure 18(a) is a flowchart of a control method according to one exemplary embodiment, and Figure 18(b) is a flowchart of process STa shown in Figure 18(a). [Figure 19] This is a flowchart showing an example of the process in step STd, as shown in Figure 18(b). [Figure 20] Figure 19 is a flowchart showing an example of the process in step ST7. [Figure 21] This flowchart shows another example of the process in step STd shown in Figure 18(b). [Figure 22] Figure 21 is a flowchart showing an example of the process in step ST7a. [Figure 23] This is a timing chart related to a power supply system according to one exemplary embodiment. [Modes for carrying out the invention]

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0009] Figure 1 is a diagram illustrating an example 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 unit 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 outlet for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20, which will be described later, and the gas outlet is connected to an exhaust system 40, which will be described later. The substrate support unit 11 is located in the plasma processing space and has a substrate support surface for supporting a substrate.

[0010] The plasma generation 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 a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron-cyclotron-resonance plasma (ECR), a helicon wave-excited plasma (HWP), or a surface wave plasma (SWP), etc.

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

[0012] The following describes an example configuration of a capacitively coupled plasma processing apparatus as an example of plasma processing apparatus 1. Figure 2 is a diagram illustrating an example configuration 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 unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is located inside the plasma processing chamber 10. The shower head 13 is located above the substrate support unit 11. In one embodiment, the shower 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 shower head 13, the side walls 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The substrate support unit 11 is electrically insulated from the housing of the plasma processing chamber 10.

[0014] 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 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is placed on the central region 111a of the main body portion 111, and the ring assembly 112 is placed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also called the substrate support surface for supporting the substrate W, and the annular region 111b is also called the 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 placed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b placed 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. Other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may also have an annular region 111b. In this case, the ring assembly 112 may be placed on the annular electrostatic chuck or the annular insulating member, or 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 covering ring. The edge rings are formed of a conductive or insulating material, and the covering rings are formed of an insulating material.

[0017] The substrate support section 11 may also include a temperature control 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 control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid, such as brine or gas, flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are arranged within the ceramic member 1111a of the electrostatic chuck 1111. The substrate support section 11 may also include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0018] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlet ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s through the plurality of gas inlet ports 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 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 processing gas to the shower head 13 from a corresponding gas source 21 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one processing gas.

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

[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 in 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 the 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 the source frequency. The source high-frequency power HF has a sinusoidal waveform whose frequency is the source frequency. The source frequency may be in the 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 unit 33 and is configured to supply source high-frequency power HF to the high-frequency electrode. The high-frequency electrode may be located within the substrate support portion 11. The high-frequency electrode may be at least one electrode located within the conductive member or ceramic member 1111a of the base 1110. Alternatively, the high-frequency electrode may be an upper electrode. When source high-frequency power HF is supplied to the high-frequency electrode, plasma is generated from the gas in the chamber 10.

[0023] The matching circuit 33 has a variable impedance. The variable impedance of the matching circuit 33 is set to reduce reflections of the source high-frequency power HF from the load. The matching circuit 33 can be controlled, for example, by 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 consist of a programmable processor or a programmable logic device such as an FPGA (Field-Programmable Gate Array).

[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 source high-frequency power HF. The amplification factor of the amplifier 31a is specified by the control unit 2 to the high-frequency power supply 31. Note that the high-frequency power supply 31 does not necessarily 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 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 the 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 1111a of the base 1110. The bias electrode may be common to the high-frequency electrode. When the electric bias EB is supplied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0027] Refer to Figure 3 below in conjunction with Figure 2. Figure 3 shows an example of an electrical bias waveform. The bias power supply 32 has a waveform period C W The system is configured to periodically apply an electrical bias EB having a waveform period C to the bias electrode. That is, the electrical bias EB has a waveform period C W Multiple waveform periods C are repeated. W A bias electrode is applied in each of these. Waveform period C W The bias frequency f EB It is defined by the bias frequency f. EB This refers to frequencies, for example, between 50 kHz and 27 MHz. Waveform period C W The duration of this function is the reciprocal of the bias frequency.

[0028] The electrical bias EB may be a bias high-frequency power LF having a bias frequency. That is, the electrical 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 the matcher 34. The variable impedance of the matcher 34 is set to reduce reflection from the load of the bias high-frequency power LF.

[0029] Alternatively, the electrical bias EB may include a voltage pulse VP. The voltage pulse VP is applied to the bias electrode within the waveform period C. W The voltage pulse VP is periodically applied to the bias electrode at a time interval having the same length as the time length of the waveform period C. The waveform of the voltage pulse VP can be a rectangular wave, a triangular wave, or any 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 and draw ions from the plasma into the substrate W. The voltage pulse VP is applied to the bias electrode so that the period during which the potential of the substrate W is a negative potential is included in the waveform period C. W 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 pulse of a negative voltage or a pulse of a negative DC voltage. Note that when the electrical bias EB is the voltage pulse VP, the plasma processing apparatus 1 may not include the matcher 34. W

[0030] As shown in Figure 2, the plasma processing apparatus 1 may further include a sensor 35 and / or a sensor 36. Sensor 35 is configured to measure the power level Pr of the reflected wave from a source high-frequency power HF load. Sensor 35 may include, for example, a directional coupler. The directional coupler may be provided between the high-frequency power supply 31 and the matching unit 33. Sensor 35 may further measure the power level Pf of the traveling wave of the source high-frequency power HF. The power level Pr of the reflected wave measured by sensor 35 is communicated to the high-frequency power supply 31. In addition, the power level Pf of the traveling wave may be communicated from sensor 35 to the high-frequency power supply 31. Sensor 35 may also communicate the reflectance, i.e., Pr / Pf, to the high-frequency power supply 31. The reflectance may be determined in the high-frequency power supply 31 from the power levels Pf and Pr. A detection circuit 35b may be connected between 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] Sensor 36 includes a voltage sensor and a current sensor. Sensor 36 measures the voltage V in the power supply circuit connecting the high-frequency power supply 31 and the high-frequency electrode. S and current I S It is configured to measure the voltage V. The source high-frequency power HF is supplied to the high-frequency electrode via this feed line. The sensor 36 may be located between the high-frequency power supply 31 and the matching unit 33. S and current I S This is communicated to the high-frequency power supply 31. Sensor 36 detects the voltage V S and current I S The impedance Z of the load of the high-frequency power supply 31 identified from L The high-frequency power supply 31 may be notified of this. Impedance Z L In the high-frequency power supply 31, the voltage V S and current I S It may be identified from. Sensor 36 has a voltage V S and current I S The phase difference θ between them may be communicated to the high-frequency power supply 31. The phase difference θ is the voltage V in the high-frequency power supply 31. S and current IS It may be identified from. Sensor 36 has a voltage V S and current I S The reflection coefficient Γ identified from may be notified to the high-frequency power supply 31. The reflection coefficient Γ is determined by the voltage V at the high-frequency power supply 31. 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 also apply a negative DC voltage to the upper electrode. The DC power supply 38 may also be a variable DC power supply.

[0033] The following references are made to Figures 4-17, along with Figures 2 and 3. Each of Figures 4-17 is an example timing chart related to a power supply system according to one exemplary embodiment. Each of Figures 4-17 shows the power level of the source high-frequency power HF and the level of the electrical bias EB. In each of Figures 4-17, "ON" for the electrical bias EB indicates that the electrical bias EB is being supplied, and "OFF" for the electrical bias EB indicates that the supply of the electrical bias EB has been stopped. In each of Figures 4-17, "HIGH" for the electrical bias EB indicates that an electrical bias EB with a level higher than the level indicated by "LOW" is being supplied. Note that if the electrical bias EB is the bias high-frequency power LF, the level of the electrical bias EB is the power level of the bias high-frequency power LF. If the electrical bias EB includes a voltage pulse VP, the electrical bias EB has a higher level as the energy of the ions attracted to the substrate W increases. If the electrical bias EB includes a voltage pulse VP, the level of the electrical bias EB may be the absolute value of the negative voltage level of the voltage pulse VP relative to a reference voltage (e.g., 0V). Also, in Figure 14, the duty cycle D VP This is further shown. Duty cycle D VP The waveform period C W This is the proportion of the time duration occupied by the time duration during which the voltage pulse VP is supplied. Also, in Figure 15, the bias frequency f EBThis is further shown. Also, the DC voltage DCS is further shown in Figures 16 and 17. 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 DC voltage DCS is not being supplied. In each of Figures 16 and 17, "HIGH" for the DC voltage DCS indicates that a DC voltage DCS with 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 negative voltage level of the DC voltage DCS relative to its reference voltage level (e.g., 0V).

[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 the power supply control unit. The power supply control unit sets the modulation period C as shown in Figures 4 to 17. M The system is configured to periodically modulate the power level of the source high-frequency power HF during the repetition of the process. The power control unit may be located inside the high-frequency power supply 31 or outside the high-frequency power supply 31. The signal generator 31g may function as the power control unit, or another device inside the high-frequency power supply 31 may function as the power control unit. Alternatively, the control unit 2 may function as the power control unit.

[0035] Furthermore, as shown in Figures 4 to 17, the power control unit controls the modulation period C M The power supply control unit may be configured to periodically modulate the electrical bias EB condition during the repetition of the process. The modulation period C M The level of the electrical bias EB may be periodically modulated during the repetition of the process. As shown in Figure 14, the power supply control unit modulates the modulation period C M In the repetition of this process, the duty cycle D VP The modulation period C may be periodically modulated. As shown in Figure 15, the power control unit controls the modulation period C M In the repetition of this, the bias frequency f EBThe modulation period C may be modulated periodically. Furthermore, as shown in Figures 16 and 17, the power control unit modulates the modulation period C M The voltage level of the DCS may be periodically modulated during the repetition of this process.

[0036] As shown in Figures 4 to 17, the modulation period C M P is a series of subperiods S This includes P S The number in parentheses that follows represents the modulation period C. M Sub-period P S This represents the order. As shown in Figures 4 to 17, the modulation period C M This refers to at least two sub-periods P where the power level of the source high-frequency power HF is set to be greater than zero and to different levels from each other. S This includes multiple subperiods P shown in the examples in Figures 4 to 15. S Each of these is a period in which the power level of the source high-frequency power HF and the conditions of the electrical bias EB remain the same. In the examples shown in Figures 16 and 17, there are multiple sub-periods P. S Each of these is a period during which the power level of the source high-frequency power HF, the conditions of the electrical 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 subperiods P S Each of these has a feedback period P that continues from the start, when the source high-frequency power HF has a power level greater than 0 watts. F [1] (First feedback period) is included. As shown in Figures 4 to 12, there are multiple sub-periods P. S Each of these has a feedback period P F [1] The remaining period is the feedback period P. F [2] (a second feedback period) may be included. Alternatively, multiple subperiods P S At least one of these sub-periods is the feedback period P F [1] may be included only. That is, multiple subperiods P SAt least one of these sub-periods is the feedback period P F [1] may be the same. S [1] is the feedback period P F [1] only. Or, multiple subperiods P S Each of these has a feedback period P F [1] may be included only. That is, multiple subperiods P S Each of these has a feedback period P F [1] may be the same as [1].

[0038] The high-frequency power supply 31 suppresses reflections from the load of the source high-frequency power HF by the modulation period C M Each phase period P within H The source frequency f is adjusted. The source frequency f is specified to the high-frequency power supply 31 by the power supply control unit. The adjustment of the source frequency f will be explained below with reference to Figures 2 to 17, as well as Figures 18(a) and 18(b). Figure 18(a) is a flowchart of a control method according to one exemplary embodiment, and Figure 18(b) is a flowchart of process STa shown in Figure 18(a). In the control method shown in Figure 18(a) (hereinafter referred to as "method MT"), each part of the power supply system 30 is controlled by the power supply control unit.

[0039] As shown in Figure 18(a), method MT includes steps STa and STb. In step STa, source high-frequency power HF is supplied from a high-frequency power supply 31 to the high-frequency electrode to generate plasma in the chamber 10 of the plasma processing apparatus 1. In step STb, a waveform period C is supplied to draw ions from the plasma onto the substrate W on the substrate support 11. W Electrical bias EB is repeatedly supplied to the substrate support part 11 (i.e., the bias electrode) at the specified time interval.

[0040] As shown in Figure 18(b), process STa includes processes STc and STd. In process STc, the modulation period C is as shown in the examples in Figures 4 to 17. MIn the repetition, the power level of the source high-frequency power HF is periodically modulated. In step STb, the modulation period C M In the repetition, the level of the electrical bias EB may be periodically modulated. Also, as shown in FIGS. 16 and 17, the modulation period C M In the repetition, the level of the DC voltage DCS may be periodically modulated.

[0041] In step STd, for each phase period P M within each modulation period C H the source frequency f is adjusted so as to suppress the degree of reflection of the source high-frequency power HF. Hereinafter, the processing in step STd will be described in more detail. In the following description, the modulation period C M [y] represents the y-th modulation period C M in the repetition of the modulation period C M The phase period P H [k] represents the k-th phase period within the modulation period C M Also, the phase period P H [j] represents the j-th phase period within the waveform period C W [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​A plurality of phase periods P within [m] H Among them, a plurality of frequencies included in a frequency set prepared in advance for the waveform period are each used as the source frequency f. Note that "Y1" is an integer of 1 or more, for example, 5.

[0044] Modulation period C M [1] to modulation period C M Feedback period P in each of [Y1] F Waveform period C within [2] W A plurality of phase periods P within [m] H In each of them, the frequency determined by the second feedback described later may be used as the source frequency f. Alternatively, modulation period C M [1] to modulation period C M Feedback period P in each of [Y1] F A plurality of waveform periods C within [2] W A plurality of phase periods P within each of them H Among them, the immediately preceding feedback period P F Final waveform period C within [1] W A plurality of phase periods P within it H The plurality of source frequencies f used in it may each be used.

[0045] <Setting of source frequency in modulation period after the Y2 - th modulation period>

[0046] Y2 - th modulation period C M Each modulation period C after [Y2] M Feedback period P in it F Phase period P within [1] H In [k], the frequency determined by the first feedback described later is used as the source frequency f. Alternatively, modulation period C M Each modulation period C after [Y2] M Feedback period P in it F Waveform period C within [1] W A plurality of phase periods P within [m] HIn each of these, the frequency determined by the first feedback, which will be described later, is used as the source frequency f.

[0047] Fragment period C M Each modulation period C from [Y2] onward M Feedback period P F [2] Waveform period C W Multiple phase periods P within [m] H In each of these, the frequency determined by the second feedback described later may be used as the source frequency f. Alternatively, the modulation period C M Each modulation period C from [Y2] onward M Feedback period P F [2] Multiple waveform periods C W Multiple phase periods P within each of these. H So, what about the previous feedback period P? F [1] Final waveform period C W Multiple phase periods P within H Multiple source frequencies f used in the above may be used individually.

[0048] Note that "Y2" could be Y1+1. Alternatively, it could be the modulation period C. M From [Y1] to modulation period C M A delay time may be introduced between [Y2] and [Y2]. The delay time may be several seconds. If a delay time is introduced, the modulation period C M Immediately after [Y1], modulation period C M Each modulation period C up to immediately before [Y2] M Multiple phase periods P in H The source frequency is the modulation period C. M Multiple phase periods P in [Y1] H Multiple source frequencies f used in the above may be used individually.

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

[0050] In the first feedback, the modulation period C M The repetition of this, i.e., multiple modulation periods C M is a periodic series C S This forms the second feedback loop, where the modulation period C M Feedback period P within [y] F [2] Multiple waveform periods C W and its feedback period P F [2] I immediately before ref Individual waveform period C W is a periodic series C S This forms the first feedback loop, where the modulation period C M Phase period P H The source frequency f of [k] is the preceding modulation period C M Phase period P in the sequence H The degree of reflection 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. In the second feedback, the modulation period C M Feedback period P within [y] F [2] Waveform period C W Phase period P at [m] H The source frequency f of [j] is the same as the feedback period P. F [2] The preceding multiple waveform periods C W Phase period P in the sequence H 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, the degree of reflection is determined in such a way as to suppress the reflection. In each of the first and second feedbacks, the source frequency f is determined by the power supply control unit.

[0051] The modulation period C in the first feedback is described below. M Phase period P in the sequenceH [k] and waveform period C in the second feedback W Phase period P in the sequence H Each of [j] is a periodic sequence C S Phase period P H Refer to it as [n]. Also, the modulation period C in the first feedback. M and the waveform period C in the second feedback W Each of them has a period C R Refer to it as follows.

[0052] As shown in Figure 19, process STd may include processes ST1 to ST7. Processes ST1 to ST7 are part of the periodic sequence C S Each period C in R Each phase period P within H It is performed against.

[0053] In process ST1, the power control unit sets i to I ini -I ref Set it to "i" for the periodic sequence C. S Period C included R This represents the order. In the first feedback, "I ini Initially, this is the aforementioned "Y2". In the first feedback, "I ini -I ref " is the periodic series C S I included in ini The second period C R The previous period C R This represents the order, "I ref " is 1. Also, in the second feedback, "I ini Initially, the value is "1". In the second feedback, the value is "I ini -I ref " is the periodic series C S I included in ini The second period C R I ref Previous period C R This represents the order, "I ref " is an integer greater than or equal to 1. In the second feedback, "I ref" may be 1, may be 2, or may be an integer greater than 2. Note that in the second feedback, I ref If the value is 2 or greater, then each phase period P in the second feedback H A relatively long processing time is allocated for determining the source frequency.

[0054] In the subsequent process ST2, the power control unit determines the degree of reflection P d Determine whether [i,n] is large enough to satisfy the frequency change condition. Note that P d [i,n] is a periodic sequence C S The i-th period C included R [i] Phase period P H [n] represents the degree of reflection. In process ST2, the frequency change condition is the degree of reflection P d This condition is met when [i,n] is greater than the threshold. In process ST2, the frequency change condition is P d [i,n] is the first threshold P th1 This condition may be satisfied if it is greater than [n]. Note that there are multiple phase periods P. H The first threshold P for each th1 They may be the same as or different from each other.

[0055] If it is determined in step ST2 that the frequency change condition is met, the power supply control unit, in step ST3, sets the source frequency f[i+I ref Set n] by equation (1). f[i+I ref ,n]=f[i,n]+Δf[i,n] …(1) Note that f[i,n] is a periodic sequence C S The i-th period C included R [i] Phase period P H [n] represents the source frequency f, and Δf[i,n] is the shift value, whose initial value is set in advance.

[0056] On the other hand, if it is determined in step ST2 that the frequency change condition is not met, the power supply control unit, in step ST4, sets the source frequency f[i+I ref Set n] by equation (2). f[i+I ref ,n]=f[i,n] …(2)

[0057] Next, processes ST5 to ST7 are performed. Processes ST5 to ST7 are repeated until an instruction to terminate is given. Process ST5 includes processes ST5a, ST5b, and ST5c. In process ST5a, I ref It is determined whether or not it is greater than 1. ref If the value is 1, the process proceeds to step ST5c. ref If is greater than 1, in step ST5b, the power control unit sets f[i+h,n] to f[i,n]. The process in step ST5b is to change h from 1 to I ref The process is carried out by incrementing by 1 until it reaches -1. Then, the process proceeds to step ST5c.

[0058] In process ST5c, the power control unit sets i to 1+I ref It increments by only that much. In the subsequent process ST6, the power control unit controls the periodic sequence C S Period C in R [i] Phase period P H At [n], a source high-frequency power HF having a source frequency f[i,n] is supplied from the high-frequency power supply 31.

[0059] In the subsequent step ST7, the power control unit determines the degree of reflection P d Periodic sequence C depending on [i,n] S Later period C in R [i+I ref Phase period P within ] H Source frequency f[i+I] for [n] ref Determine n].

[0060] As shown in Figure 20, process ST7 starts with process ST701. In process ST701, the power control unit controls the degree of reflection P dDetermine whether [i,n] is increasing or not. In step ST701, the degree of reflection P d [i,n] is P d [i,n]>P d [iI ref If the condition [,n] is satisfied, it may be determined that there is an increasing trend. Alternatively, the periodic series C S The i-th period C in R X periods C up to [i] R Phase period P H If the degree of reflection at [n] is increasing, then the degree of reflection P d It may be determined that [i,n] is increasing. Here, "X" is an integer greater than or equal to 2. Periodic sequence C S The i-th period C in R X periods C up to [i] R C R [ix×I ref It is represented as ], where "x" is an integer from 0 to (X-1).

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

[0062] On the other hand, in process ST701, the degree of reflection P d If it is determined that [i,n] is increasing, the power control unit changes the sign of the shift value Δf[i,n] in step ST703. That is, in step ST703, the power control unit sets the shift value Δf[i,n] by equation (4). Δf[i,n]=-Δf[iI ref ,n] …(4)

[0063] In the subsequent step ST704, the power supply control unit determines whether the shift direction change condition is met. The shift direction change condition is determined by the source frequency f[i,n] and the period C. R [i] the (nu)-th phase period P H The absolute value of the difference between [nu] and the source frequency f[i,nu], and the relationship between the source frequency f[i,n] and the period C. R [i] The (n+u)th phase period P H The shift direction change condition is met when, as a result of comparing the absolute values ​​of the difference between source frequency [n+u] 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,nu] and source frequency f[i,n+u] are greater than or less than source frequency f[i,n]. For example, the shift direction change condition is met when the absolute values ​​of the difference between source frequency f[i,n] and source frequency f[i,nu] and the absolute values ​​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,nu] and source frequency f[i,n+u] are greater than or less than source frequency f[i,n].

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

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

[0066] On the other hand, if it is determined in process ST704 that the shift direction change condition is not met, the power control unit maintains the sign of the shift value Δf[i,n] in process ST706. That is, in process ST706, the power 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 control unit controls the periodic sequence C S Period C in R [i] Phase period P H [n] The degree of reflection P of the source high-frequency power HF d It is determined whether [i,n] is large enough to satisfy the frequency change condition. In step ST707, the frequency change condition is the periodic sequence C S Period C in R [i] Phase period P H [n] The degree of reflection P of the source high-frequency power HF d This condition is met if [i,n] is greater than the threshold.

[0068] If it is determined in step ST707 that the frequency change condition is met, the power supply control unit, in step ST708, sets the periodic sequence C S Later period C in R [i+I ref Phase period P within ] H Source frequency f[i+I] for [n] ref Set n] by equation (7). f[i+I ref ,n]=f[i,n]+Δf[i,n] …(7)

[0069] On the other hand, if the frequency change condition is not met in step ST707, the power supply control unit, in step ST709, sets the source frequency f[i+I ref Set n] by equation (8). f[i+I ref ,n]=f[i,n] …(8)

[0070] In one embodiment, periodic sequence CS one of the periods C R Phase period P in H The degree of reflection at [n] and the first threshold P th1 If, as a result of the comparison in step ST707 between [n] and [n], it is determined that the degree of reflection is small, then in the subsequent step ST707, period C R Phase period P in H The degree of reflection at [n] and the second threshold P th2 The frequency change condition in step ST707 does not need to be met until, as a result of the comparison with [n], it is determined that the degree of reflection is large. Second threshold P th2 [n] is the first threshold P th1 [n] or greater. Second threshold P th2 [n] is the first threshold P th1 [n] may be greater than [n]. Note that there may be multiple phase periods P. H [n] Second threshold P for each th2 [n] may be the same as or different from each other.

[0071] Specifically, periodic series C S one of the periods C R Phase period P in H The degree of reflection at [n] is the first threshold P in process ST707. th1 If it is determined that [n] is less than or equal to [n], then in subsequent step ST707, the phase period P H A second threshold P is used as a threshold to compare with the degree of reflection at [n]. th2 [n] may also be used. And the periodic sequence C S Phase period P in any of the waveform periods within H The degree of reflection at [n] is the second threshold P in process ST707. th2 If it is determined to be greater than [n], then in the subsequent process ST707, the phase period P H The first threshold P is used as a threshold to compare with the degree of reflection at [n]. th1 [n] may also be used.

[0072] In method MT, the degree of reflection P dThe source frequency f[i+I] depends on [i,n] ref By adjusting [n], reflection of the source high-frequency power HF is suppressed. Also, when the shift direction change condition is met, i.e., each period C R If a large fluctuation in source frequency occurs within the period C, resulting in a large increase or decrease in source frequency followed by a large decrease or increase in source frequency, the sign of the shift value is changed. Therefore, according to method MT, period C R Large fluctuations in the source frequency within the system are suppressed. Also, as mentioned above, the first threshold P in determining the frequency change condition th1 and the second threshold P th2 By using this method, excessive changes in the source frequency are suppressed. Furthermore, when the MT method is repeated, high reproducibility of the time variation of the source frequency can be achieved. Note that the step ST7 shown in Figure 20 does not necessarily include steps ST704 to ST706.

[0073] The following describes another example of the process in step STd 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 following describes the process in step STd shown in Figures 21 and 22 from the perspective of the differences from the processes shown in Figures 19 and 20. In the processes shown in Figures 21 and 22, the power control unit uses the shift value Δf[i,n] to determine the degree of reflection P d Set to a value corresponding to the size of [i,n].

[0074] Specifically, as shown in Figure 21, the power control unit sets the source frequency f[i,n] and coefficient α[i,n] in the process between process ST1 and process ST3. In the process between process ST1 and process ST3, the source frequency f[i,n] and coefficient α[i,n], i.e., the source frequency f[1,n] and coefficient α[1,n], are initially set to their respective pre-set values.

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

[0076] Then, in step ST7a following step ST6, the power control unit determines the degree of reflection P d Periodic sequence C depending on [i,n] S Later period C in R [i+I ref Phase period P within ] H Source frequency f[i+I] for [n] ref Determine n].

[0077] As shown in Figure 22, process ST7a starts with process ST701. In process ST701, the degree of reflection P d If it is determined that [i,n] is not increasing, the power control unit maintains the sign of the coefficient α[i,n] in step ST702a. That is, the power control unit sets the coefficient α[i,n] in step ST702a using equation (10). α[i,n]=α[iI ref ,n] …(10)

[0078] On the other hand, in process ST701, the degree of reflection P d If it is determined that [i,n] is increasing, the power control unit changes the sign of the coefficient α[i,n] in step ST703a. That is, in step ST703a, the power control unit sets the coefficient α[i,n] by equation (11). α[i,n]=-α[iI ref ,n] …(11)

[0079] As shown in Figure 22, if it is determined in process ST704 that the shift direction change condition is met, the power control unit changes the sign of the coefficient α[i,n] in process ST705a. That is, in process ST705a, the power control unit sets the coefficient α[i,n] by equation (12). α[i,n]=|α[iI ref ,n]|*sign(f[i,n]-f[i,nu]) …(12) Here, u is the value of u when the shift direction change condition is met.

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

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

[0082] In the example in Figure 22, the periodic series C S one of the periods C R Phase period P in H The degree of reflection at [n] and the first threshold P th1 If, as a result of the comparison in step ST707 between [n] and [n], it is determined that the degree of reflection is small, then in the subsequent step ST707, period C R Phase period P in H The degree of reflection at [n] and the second threshold P th2The frequency change condition in step ST707 does not need to be met until, as a result of the comparison with [n], it is determined that the degree of reflection is large. Second threshold P th2 [n] is the first threshold P th1 [n] or greater. Second threshold P th2 [n] is the first threshold P th1 [n] may be greater than [n]. Note that there may be multiple phase periods P. H [n] Second threshold P for each th2 [n] may be the same as or different from each other.

[0083] Specifically, periodic series C S one of the periods C R Phase period P in H The degree of reflection at [n] is the first threshold P in process ST707. th1 If it is determined that [n] is less than or equal to [n], then in subsequent step ST707, the phase period P H A second threshold P is used as a threshold to compare with the degree of reflection at [n]. th2 [n] may also be used. And the periodic sequence C S Phase period P in any of the waveform periods within H The degree of reflection at [n] is the second threshold P in process ST707. th2 If it is determined to be greater than [n], then in the subsequent process ST707, the phase period P H The first threshold P is used as a threshold to compare with the degree of reflection at [n]. th1 [n] may be used. Note that the process ST7a shown in Figure 22 does not necessarily have to include processes ST704, ST705a, and ST706a.

[0084] The degree of reflection P is as follows: d Let's explain [i,n]. The degree of reflection P. d [i,n] is a periodic sequence C S Phase period P within the period CR[i] HThis is obtained by acquiring multiple evaluation values ​​at each of the multiple sampling time points in [n]. The multiple evaluation values ​​reflect the magnitude of the reflection of the source high-frequency power HF at each of the multiple sampling time points. Multiple phase periods P H The number of samples at each sampling point can be the same.

[0085] Degree of reflection P d [i,n] is a periodic sequence C S Phase period P within the period CR[i] H These are representative values ​​of the evaluation values ​​at each of the multiple sample time points in [n]. The representative value is the average of the multiple evaluation values, the weighted average of the multiple evaluation values, or the maximum value of the multiple evaluation values, etc. Each of the multiple evaluation values ​​is a measurement obtained by sensors 35, 36, such as the power level Pr of the reflected wave, reflectance (i.e., Pr / Pf), and impedance Z. L The magnitude of the difference between the characteristic impedance and the voltage V may also be the reflection coefficient Γ. Each of the multiple evaluation values ​​may be the input of the matching circuit 33 (i.e., the input of the matching circuit 33 on the high-frequency power supply 31 side) or the difference between the resistance value of the source high-frequency power HF transmission system as seen from the high-frequency power supply 31 and a predetermined resistance value (e.g., 50Ω). Alternatively, each of the multiple evaluation values ​​may be the voltage V at the input of the source high-frequency power HF transmission system or the matching circuit. S and current I S This could also be the difference between the phase difference between two points 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 the period CR[i] H This is the weighted average of the evaluation values ​​at each of the multiple sampling time points in [n]. To obtain the weighted average, the power control unit calculates the average of multiple values ​​obtained by multiplying the multiple evaluation values ​​by a window function. The window function is the phase period P H The weights decrease according to the time difference from the center of [n]. Examples of window functions used include the triangular window, Gaussian window, Hanning window, or Hamming window. According to the weighted average using such window functions, each phase period P HThe degree of reflection P that can occur due to the phase of the source high-frequency power HF. d It is possible to suppress the variation in the calculated values ​​of [i,n].

[0087] Now, refer to Figure 23. Figure 23 is a timing chart related to a power supply system according to one exemplary embodiment. The high-frequency power supply 31 has a waveform period C W The source high-frequency power HF may be supplied continuously over the entire period. Alternatively, the high-frequency power supply 31 may have a waveform period C W The source high-frequency power HF may be pulsed internally. That is, the high-frequency power supply 31 has a waveform period C W A pulse with source high-frequency power HF may be supplied internally.

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

[0089] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E10] below.

[0090] [E1] 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 source 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 source 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 source 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 supply control unit is configured to adjust the source frequency of the source high-frequency power for the k-th phase period within the modulation cycle included in the feedback period, based on the change in the source frequency of the k-th phase period in the preceding repetition of the modulation cycle and the change in the degree of reflection of the source high-frequency power, in order to suppress the degree of reflection of the source high-frequency power. Plasma processing equipment.

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

[0092] [E3] 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 source high-frequency power, the electrical bias conditions, and the output voltage level of the DC power supply during each of the plurality of sub-periods. The plasma processing apparatus described in E1.

[0093] [E4] 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. A plasma processing apparatus as described in E2 or E3.

[0094] [E5] 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. A plasma processing apparatus as described in E2 or E3.

[0095] [E6] 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 that the sequence of source frequencies used in the waveform period immediately preceding the second feedback period is repeatedly used during the second feedback period. A plasma processing apparatus as described in any one of items E1 to E5.

[0096] [E7] 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 source frequency for the j-th 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 source frequency in the j-th phase period in the preceding repetition of the waveform period and the 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. A plasma processing apparatus as described in any one of items E1 to E5.

[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 the same as the length of the feedback period.

[0098] [E9] A high-frequency power supply configured to supply source 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 source 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 source 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 supply control unit is configured to adjust the source frequency of the source high-frequency power for the k-th phase period within the modulation cycle included in the feedback period, based on the change in the source frequency of the k-th phase period in the preceding repetition of the modulation cycle and the change in the degree of reflection of the source high-frequency power, in order to suppress the degree of reflection of the source high-frequency power. Power supply system.

[0099] [E10] (a) A step of supplying source high-frequency power from a high-frequency power supply to generate plasma in the chamber of the plasma processing apparatus, (b) A step of supplying an electrical bias to the substrate support portion at a time interval 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 source 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 source 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 source frequency of the source high-frequency power for the k-th phase period within the modulation cycle included in the feedback period, wherein the source frequency for the k-th phase period within the modulation cycle is adjusted to suppress the degree of reflection of the source high-frequency power, based on the change in the source frequency of the k-th phase period and the change in the degree of reflection of the source high-frequency power in the preceding repetition of the modulation cycle. A control method including

[0100] From the above description, it will be understood that the various embodiments of this disclosure are described herein for illustrative purposes and can be modified in various ways without departing from the scope and spirit of this disclosure. Accordingly, the various embodiments disclosed herein are not intended to limit the scope and spirit, and the true scope and spirit are shown by the appended claims. [Explanation of symbols]

[0101] 1...Plasma processing apparatus, 10...Chamber, 11...Substrate support section, 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.

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