Plasma processing apparatus, plasma processing method, and program

Abstract

In a disclosed plasma processing device, a first processing condition including the provision of a first processing gas into a chamber and a second processing condition including the provision of a second processing gas into the chamber are respectively applied in a first processing period and a second processing period. In each of the first and second processing periods, source high-frequency power is supplied to generate plasma and an electrical bias is supplied to a board support part. In the first processing period, a plurality of frequencies in a first frequency set are used in the order of frequencies of the source high-frequency power within a waveform period of the electrical bias. In the second processing period, a plurality of frequencies in a second frequency set are used in the order of frequencies of the source high-frequency power within a waveform period of the electrical bias.

Description

Plasma processing apparatus and plasma processing method

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

[0002] A plasma processing apparatus is used in plasma processing of a substrate. The plasma processing apparatus uses bias high frequency power to attract ions from a plasma generated in a chamber to the substrate. Patent Document 1 listed below discloses a plasma processing apparatus that modulates the power level and frequency of the bias high frequency power.

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

[0004] The present disclosure provides techniques for reducing the degree of reflection of source RF power.

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a gas supply, a radio frequency power source, and a bias power source. The substrate support is disposed within the chamber. The gas supply is configured to supply gas into the chamber. The radio frequency power source is configured to supply source radio frequency power to generate plasma from the gas within the chamber. The bias power source is electrically coupled to the substrate support and configured to generate an electric bias. During a first processing period, the radio frequency power source uses a plurality of frequencies included in a first frequency set determined to reduce a degree of reflection of the source radio frequency power from a load as a source frequency of the source radio frequency power for each of a plurality of phase periods within a waveform period of the electric bias. During the first processing period, first processing conditions are applied, including supplying a first process gas from the gas supply into the chamber. During a second processing period, the radio frequency power source uses a plurality of frequencies included in a second frequency set determined to reduce a degree of reflection of the source radio frequency power from the load as a source frequency of the source radio frequency power for each of a plurality of phase periods within a waveform period of the electric bias. During the second processing period, second processing conditions are applied, including supplying a second process gas into the chamber from the gas supply.

[0006] According to one exemplary embodiment, it is possible to reduce the degree of reflection of source RF power.

[0007] 7A, 7B, and 7C are diagrams illustrating an example of the configuration of a plasma processing system; FIG. 7A is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus; FIG. 7B is a diagram illustrating an example of the configuration of a power supply system in a plasma processing apparatus according to an exemplary embodiment; FIG. 7C is a timing chart illustrating an example of an electrical bias used in a plasma processing apparatus according to an exemplary embodiment; FIG. 7C is a timing chart illustrating an example of a source frequency of an electrical bias and a source high frequency power used in a plasma processing apparatus according to an exemplary embodiment; FIG. 7D is a timing chart related to a plasma processing apparatus according to an exemplary embodiment; FIG. 7E is a flowchart illustrating a plasma processing method 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 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 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 may be implemented by, for example, 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 a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[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] Hereinafter, reference will be made to FIG. 3 together with FIG. 2. FIG. 3 is a diagram showing an example of the configuration of a power supply system in a plasma processing apparatus according to an exemplary embodiment. The power supply system 30 includes a high frequency power supply 31 and a bias power supply 32. The high frequency power supply 31 constitutes the plasma generating unit 12 of the embodiment. The high frequency power supply 31 is configured to generate a source high frequency power HF. The source high frequency power HF has a source frequency f ＨＦThe source frequency f ＨＦ The power level of the source high frequency power HF or its pulsed HFP (described later) can be specified to the high frequency power supply 31 by the control unit 2.

[0022] The high frequency power supply 31 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 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 high frequency power supply 31 is electrically connected to the high frequency electrode via a matching box 33. The matching box 33 has a variable impedance. The variable impedance of the matching box 33 is set to reduce reflection of the source high frequency power HF from the load of the high frequency power supply 31. The matching box 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 source frequency f ＨＦ The signal generator 31g generates a high-frequency signal having a frequency of 100 kHz. The signal generator 31g may be configured from a programmable logic device such as a programmable processor or a field-programmable gate array (FPGA). The signal generator 31g may be configured together with the signal generator 32g (described later) as a single programmable device, or may be configured from a programmable device separate from the signal generator 32g.

[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 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 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. Alternatively, the amplifier 31a may directly receive frequency information from the signal generator 31g and generate source high-frequency power HF having a source frequency specified by the frequency information.

[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] In one embodiment, the bias power supply 32 may include a signal generator 32g, a D / A converter 32c, and an amplifier 32a, as shown in Figure 3. The signal generator 32g generates a bias signal having a specified waveform. The signal generator 32g may be configured with a programmable processor or a programmable logic device such as an FPGA.

[0028] The output of the signal generator 32g is connected to the input of the D / A converter 32c. The D / A converter 32c converts the bias signal from the signal generator 32g into an analog signal. The output of the D / A converter 32c is connected to the input of the amplifier 32a. The amplifier 32a amplifies the analog signal from the D / A converter 32c to generate the electric bias EB. The gain of the amplifier 32a is specified to the bias power supply 32 by the control unit 2. Note that the bias power supply 32 does not need to include the D / A converter 32c. In this case, the output of the signal generator 32g is connected to the input of the amplifier 32a, and the amplifier 32a generates the electric bias EB from the voltage waveform or power information of the bias signal from the signal generator 32g.

[0029] 2 and 3, reference will now be made to FIG. 4. FIG. 4 is a timing chart showing an example of an electric bias used in a plasma processing apparatus according to one exemplary embodiment. The electric bias EB or a pulse EBP thereof, which will be described later, has a waveform period CY as shown in FIG. 4, and is periodically supplied to the bias electrode from the bias power supply 32. The waveform period CY of the electric bias EB is determined by the bias frequency. The bias frequency is, for example, a frequency not less than 100 kHz and not more than 50 MHz. The time length of the waveform period CY of the electric bias EB is the reciprocal of the bias frequency.

[0030] The electric bias EB may be the bias high frequency power LF as shown in Fig. 4. 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 the reflection of the bias high frequency power LF from the load.

[0031] Alternatively, the electric bias EB may be a voltage pulse sequence. The voltage pulse sequence includes periodically generated voltage pulses PV. The voltage pulses PV are applied to the bias electrode within a waveform period CY. The voltage pulses PV are periodically applied to the bias electrode at time intervals equal to the time length of the waveform period CY. The waveform of the voltage pulses PV may be a square wave, a triangular wave, or any other waveform. The polarity of the voltage pulses PV is set to generate a potential difference between the substrate W and the plasma so as to attract ions from the plasma to the substrate W. The voltage pulses PV may be negative voltage pulses or negative DC voltage pulses. When the electric bias EB includes a sequence of voltage pulses PV, the plasma processing apparatus 1 does not need to include a matching unit 34.

[0032] The level of the electric bias EB or its pulse EBP can be specified to the bias power supply 32 by the control unit 2. When the electric bias EB or its pulse EBP is a bias high frequency power LF, the level of the electric bias EB or its pulse EBP is the power level of the bias high frequency power LF. When the electric bias EB or its pulse is a voltage pulse sequence, the level of the electric bias EB or its pulse EBP is the magnitude of the voltage level of the voltage pulse PV in the negative direction relative to a reference voltage level (e.g., 0 V). The level of the electric bias EB or its pulse EBP may be the absolute value of the negative voltage level of the voltage pulse PV.

[0033] FIG. 5 is a timing chart showing an example of the source frequencies of the electric bias and source high frequency power used in a plasma processing apparatus according to one exemplary embodiment. As shown in FIG. 5, the high frequency power supply 31 changes the source frequency within the waveform period CY of the electric bias EB so as to suppress the degree of reflection of the source high frequency power HF from the load. In the plasma processing apparatus 1, the waveform period CY of the electric bias EB is divided into multiple phase periods SP. The high frequency power supply 31 changes the source frequency during the multiple phase periods SP by using multiple source frequencies for each of the multiple phase periods SP. The change in the source frequency within the waveform period CY of the electric bias EB will be described later.

[0034] Hereinafter, reference will be made to FIG. 6 along with FIGS. 2 to 5. FIG. 6 is a timing chart related to a plasma processing apparatus according to an exemplary embodiment. As shown in FIG. 6, the high-frequency power supply 31 may be configured to generate a pulse HFP of source high-frequency power HF and supply it to the high-frequency electrode. The pulse HFP may be supplied repeatedly. The pulse HFP may also be supplied periodically. The pulse period of the pulse HFP (e.g., any of the processing periods P1 to P4 described below) and the duty ratio of the pulse HFP may be specified by the control unit 2. The pulse period of the pulse HFP (e.g., each of the processing periods P1 to P4 described below) includes a period (ON period) in which the pulse HFP is in an ON (or high power level) state and a period (OFF period) in which the pulse HFP is in an OFF (or low power level) state. The duty ratio of the pulse HFP is the proportion of the period in which the pulse HFP is in an ON (or high power level) state within the pulse period of the pulse HFP.

[0035] As shown in FIGS. 4 and 6, the bias power supply 32 may be configured to generate a pulse EBP of an electric bias EB and supply it to the bias electrode. The pulse EBP may be supplied repeatedly. The pulse EBP may also be supplied periodically. The pulse period of the pulse EBP (for example, any one of processing periods P1 to P4 described later) and the duty ratio of the pulse EBP may be specified by the control unit 2. The pulse period of the pulse EBP (for example, each of processing periods P1 to P4 described later) may be a period in which the pulse EBP is set to ON (ON period P ＯＮ ) and the period set to OFF (OFF period P ＯＦＦ The duty ratio of the pulse EBP is the ON period P ＯＮ is the percentage.

[0036] In the plasma processing apparatus 1, a plurality of different processing conditions are applied to the substrate W during a plurality of processing periods (e.g., processing periods P1 to P4 in FIG. 6 ). Recipe data specifying the plurality of processing conditions and the plurality of processing periods may be stored in the storage unit 2a2 of the control unit 2. The control unit 2 controls each unit of the plasma processing apparatus 1 according to the recipe data to perform plasma processing under a corresponding processing condition among the plurality of processing conditions during each of the plurality of processing periods.

[0037] Each of the plurality of processing conditions includes supplying a processing gas from the gas supply unit 20 into the chamber 10 that is different from the processing gas supplied from the gas supply unit 20 into the chamber 10 under each of the other processing conditions among the plurality of processing conditions. The plurality of processing periods includes at least a first processing period (e.g., processing period P1 in FIG. 6 ) and a second processing period (e.g., processing period P2 in FIG. 6 ). The processing gas (first processing gas) under the first processing condition applied to the substrate W in the first processing period is different from the processing gas (second processing gas) under the second processing condition applied to the substrate W in the second processing period.

[0038] Each of the plurality of process gases for each of the plurality of process conditions may contain at least one gas component that is different from all of the gas components in each of the other process gases, or each of the plurality of process gases for each of the plurality of process conditions may contain the same plurality of gas components as each of the other process gases, but the flow rate of at least one of the plurality of gas components may be different from the flow rate of the corresponding gas component in the other process gas.

[0039] 6, the plurality of processing periods includes processing periods P1 to P4. The plurality of processing gases under the plurality of processing conditions for each of the processing periods P1 to P4 contain the same plurality of gas components as the plurality of gas components of each of the other processing gases among the plurality of processing gases. Specifically, each of the plurality of processing gases under the plurality of processing conditions for each of the processing periods P1 to P4 contains C ４ F ６ Gas, C ４ F ８ Gas, O ２The processing gas includes a nitrogen gas and an Ar gas, and the flow rate of at least one of the plurality of gas components of the processing gas in each of the processing periods P1 to P4 is different from the flow rate of the corresponding gas component in the other processing periods P1 to P4.

[0040] Specifically, as shown in FIG. 6, O ２ The gas flow rate is O ２ The flow rate of the gas is greater than the flow rate of the gas. ４ F ６ The gas flow rate is C during the processing period P1. ４ F ６ The flow rate of O in the processing period P2 is higher than that of O ２ The gas flow rate is O ２ The flow rate of the gas is less than the flow rate of the gas. ４ F ６ The gas flow rate is C during the processing period P2. ４ F ６ The flow rate of the O gas in the processing period P3 is less than that of the O ２ The gas flow rate is O ２ The flow rate of Ar gas in the processing period P3 is greater than the flow rate of Ar gas in the processing period P2. ４ F ８ The gas flow rate is C during the processing period P3. ４ F ８ The flow rate of Ar gas in the processing period P4 is larger than the flow rate of Ar gas in the processing period P3.

[0041] During the processing period P1, the shape of the mask on the substrate W may be adjusted by chemical species supplied from the plasma of the processing gas. During the processing period P2, carbon-containing deposits may be formed on the surface of the substrate W by chemical species supplied from the plasma of the processing gas. During the processing period P3, regions of the film on the substrate W exposed through the openings in the mask may be etched by chemical species supplied from the plasma of the processing gas. The film may be a silicon-containing film such as a silicon oxide film. During the processing period P4, the film may be over-etched by chemical species supplied from the plasma of the processing gas.

[0042] In one embodiment, when the electric bias EB is a voltage pulse sequence, each of the plurality of process conditions may further include at least one of a power level of the source high frequency power HF or pulse HFP, a level of the electric bias EB or pulse EBP, a duty ratio (ON duty ratio) of the voltage pulse PV, a bias frequency, and a pressure in the chamber 10. Alternatively, when the electric bias EB is a bias high frequency power LF, each of the plurality of process conditions may further include at least one of a power level of the source high frequency power HF or pulse HFP, a level of the electric bias EB or pulse EBP, a bias frequency, and a pressure in the chamber 10.

[0043] 6, the power level of the pulse HFP during processing period P4 is lower than the power level of the pulse HFP during each of processing periods P1 to P3. The level of the pulse EBP during processing period P3 is higher than the level of the pulse EBP during each of processing periods P1 and P2, and the level of the pulse EBP during processing period P4 is higher than the level of the pulse EBP during processing period P3. The duty ratios of the voltage pulse PV during processing period P2 and the voltage pulse PV during processing period P3 are higher than the duty ratios of the voltage pulse PV during processing period P1 and the voltage pulse PV during processing period P4. The pressure within chamber 10 during processing period P4 is higher than the pressure within chamber 10 during each of processing periods P1 to P3.

[0044] The high frequency power supply 31 uses a unique frequency set in each of the above-mentioned multiple processing periods (e.g., processing periods P1 to P4) to suppress reflection of the source high frequency power HF from the load. For example, the high frequency power supply 31 uses a first frequency set in a first processing period and a second frequency set in a second processing period. The unique frequency set is determined to suppress the degree of reflection of the source high frequency power HF from the load under corresponding processing conditions. The unique frequency set includes multiple frequencies. The high frequency power supply 31 uses multiple frequencies included in the unique frequency set as source frequencies for each of the multiple phase periods SP of the waveform cycle CY in each of the multiple processing periods.

[0045] In the plasma processing apparatus 1, a set of frequencies determined to suppress the degree of reflection of the source high frequency power HF from the load during a plurality of phase periods SP within a waveform period CY is selected in accordance with at least the process gas. Therefore, it is possible to reduce the degree of reflection of the source high frequency power HF during a plurality of phase periods within a waveform period CY in each of two or more process periods in which different process gases are used.

[0046] In one embodiment, in each of a plurality of processing periods (e.g., processing periods P1 to P4), as shown in FIG. 6 , a pulse HFP is supplied prior to a pulse EBP. In the period in which the pulse HFP precedes the pulse EBP, plasma is ignited. In the period in which the pulse HFP precedes the pulse EBP in each of the plurality of processing periods, the high frequency power supply 31 uses a predetermined source frequency for igniting plasma. The source frequency for igniting plasma can be specified to the high frequency power supply 31 by the control unit 2.

[0047] In one embodiment, a unique frequency set for each of a plurality of processing periods (e.g., processing periods P1 to P4) may be registered in a corresponding frequency table in a storage unit of the plasma processing apparatus 1. For example, the first frequency set and the second frequency set may be registered in a first frequency table and a second frequency table, respectively, in the storage unit. This storage unit may be the storage unit 2a2 or a storage unit in the high-frequency power supply 31.

[0048] In one embodiment, the bias power supply 32 may supply a pulse EBP in each of a plurality of processing periods (e.g., processing periods P1 to P4). The bias power supply 32 may repeatedly supply the pulse EBP in each of a plurality of pulse period sequences. Each of the plurality of pulse period sequences includes a plurality of pulse periods. The plurality of pulse periods is a repetition of a corresponding processing period among the plurality of processing periods (e.g., processing periods P1 to P4). The bias power supply 32 supplies the pulse EBP in each of the plurality of pulse periods included in each of the plurality of pulse period sequences. In one example, as shown in FIG. 6 , the bias power supply 32 repeatedly supplies the pulse EBP in each of four pulse period sequences, which are repetitions of the processing periods P1 to P4, respectively. The four pulse period sequences are composed of repetitions of corresponding processing periods (i.e., pulse periods) among the processing periods P1 to P4.

[0049] The high frequency power supply 31 may supply a pulse HFP in each of a plurality of processing periods (e.g., processing periods P1 to P4). The high frequency power supply 31 may repeatedly supply the pulse HFP in each of the plurality of pulse period sequences described above. In one example, as shown in FIG. 6 , the high frequency power supply 31 repeatedly supplies the pulse HFP in each of four pulse period sequences, which are repetitions of the processing periods P1 to P4. As shown in FIG. 6 , the pulse HFP is supplied simultaneously with the pulse EBP in at least a portion of each pulse period.

[0050] In one embodiment, the high frequency generator 31 may use a unique frequency set registered in the corresponding frequency table in one or more waveform periods CY in each processing period or each pulse period. Then, the high frequency generator 31 may adjust the source frequency for each of multiple phase periods SP of the waveform period CY in each processing period or each pulse period by first feedback. The first feedback adjusts the source frequency for each phase period SP in each processing period or each pulse period according to the degree of reflection of the source high frequency power HF obtained by using different source frequencies in the same phase periods in two or more preceding waveform periods. Details of the first feedback will be described later.

[0051] In one embodiment, the high frequency power supply 31 may adjust the source frequency for the phase period SP within each pulse period by a second feedback. The second feedback adjusts the source frequency for the phase period SP within each pulse period in each pulse period sequence according to the degree of reflection of the source high frequency power HF obtained by using different source frequencies in the same phase period within the same waveform cycle in two or more preceding pulse periods. Note that the high frequency power supply 31 may use both the first feedback and the second feedback. Details of the second feedback will be described later.

[0052] In one embodiment, the high frequency power supply 31 is turned on during an OFF period P in at least one pulse period (for example, the processing period P3 in FIG. 6). ＯＦＦ During the OFF period P, a source high frequency power HF having a power level lower than the power level of the pulse HFP may be supplied to the high frequency electrode. ＯＦＦ The source frequency of the source high frequency power HF in is determined so as to suppress the degree of reflection of the source high frequency power HF, and may be a constant frequency or may vary with time.

[0053] The first feedback and the second feedback will be described below.

[0054] [First Feedback]

[0055] The first feedback is performed to adjust the source frequency for multiple phase periods SP in each of multiple waveform periods CY within each processing period or each pulse period. Each of the multiple waveform periods CY includes N phase periods SP(1) to SP(N), where N is an integer greater than or equal to 2. The N phase periods SP(1) to SP(N) divide each of the multiple waveform periods CY into N phase periods. In the following description, waveform period CY(m) represents the mth waveform period among multiple consecutive waveform periods CY. Phase period SP(n) represents the nth phase period among phase periods SP(1) to SP(N). Furthermore, phase period SP(m,n) represents the nth phase period in waveform period CY(m).

[0056] The adjustment of the source frequency in the first feedback loop can be performed by the high frequency power source 31 (or its signal generator 31g). The high frequency power source 31 adjusts the source frequency of the source high frequency power HF in the phase period SP(m,n) in response to changes in the degree of reflection of the source high frequency power HF.

[0057] To determine the degree of reflection of the source high frequency power HF, 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 reflected wave of the source high frequency power HF from the load. The sensor 35 includes, for example, a directional coupler. This directional coupler may be provided between the high frequency power supply 31 and the matching device 33. The sensor 35 may also be configured to 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.

[0058] 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. ＨＦ and current I ＨＦThe 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 ＨＦ and current I ＨＦ is notified to the high frequency power supply 31.

[0059] The high frequency power supply 31 generates a representative value from measurements taken during each of the multiple phase periods SP. The measurement may be the power level Pr of the reflected wave acquired by the sensor 35. The measurement may be the ratio of the power level Pr of the reflected wave to the output power level of the source high frequency power HF (i.e., the reflectivity). The measurement may be the voltage V acquired by the sensor 36 during each of the multiple phase periods SP. ＨＦ and current I ＨＦ The measured value may be the impedance Z on the load side of the high frequency power supply 31 in each of the plurality of phase periods SP. The impedance Z is the voltage V acquired by the sensor 36. ＨＦ and current I ＨＦ The representative value may be the average or maximum value of the measured values ​​in each of the multiple phase periods SP. The high frequency power supply 31 uses the representative value in each of the multiple phase periods SP as a value representing the degree of reflection of the source high frequency power HF.

[0060] In the first feedback, the high frequency power supply 31 identifies changes in the degree of reflection by using different source frequencies in corresponding phase periods SP(n) in each of two or more waveform periods CY prior to the waveform period CY(m) within each processing period or each pulse period.

[0061] By using different source frequencies in the phase periods SP(n) of two or more waveform periods CY, it is possible to identify the relationship between a change in source frequency (frequency shift) and a change in the degree of reflection of the source high-frequency power. Therefore, according to the plasma processing apparatus 1, it is possible to adjust the source frequency used in the phase periods SP(m,n) in response to changes in the degree of reflection so as to reduce the degree of reflection. Furthermore, according to the plasma processing apparatus 1, it is possible to quickly reduce the degree of reflection in each of the multiple waveform periods CY in which the electric bias EB is applied to the bias electrode of the substrate support 11.

[0062] In one embodiment, two or more waveform periods CY before waveform period CY(m) are equal to waveform period CY(m-M １ ) and waveform period CY (m-M ２ ), where M １ and M ２ is M １ >M ２ In one embodiment, the waveform period CY(m-M １ ) is the waveform period CY(m-2Q), and the waveform period CY(m-M ２ ) is the waveform period CY(m-Q). ２ " can be "1", and "2Q" and "M １ " may be "2". "Q" may be an integer equal to or greater than 2.

[0063] In the first feedback, the high frequency power supply 31 generates a source frequency f(m-M ２ , n), and the source frequency f(m-M １ , n), where f(m, n) represents the source frequency of the source high frequency power HF used in the phase period SP(m, n). f(m, n) is given by f(m, n) = f(m-M ２,n)+Δ(m,n), where Δ(m,n) represents the amount of frequency shift. One frequency shift is either a frequency decrease or a frequency increase. If one frequency shift is a frequency decrease, Δ(m,n) has a negative value. If one frequency shift is a frequency increase, Δ(m,n) has a positive value.

[0064] In the first feedback, the source frequency f(m−M ２ When the degree of reflection is reduced by using the source frequency f(m, n), the high frequency power supply 31 changes the source frequency f(m-M ２ , n) is set to a frequency with one frequency shift. For example, one frequency shift results in a power level Pr(m-M ２ , n) is the power level Pr(m-M １ , n), the high frequency power supply 31 reduces the source frequency f(m, n) to the source frequency f(m−M ２ , n), where Pr(m, n) represents the power level Pr of the reflected wave of the source high frequency power HF in the phase period SP(m, n).

[0065] In the first feedback, the source frequency f(m−M ２ , n), the degree of reflection may increase. For example, the power level Pr(m-M ２ , n) is the power level Pr(m−M １ In this case, the high frequency power supply 31 may increase the source frequency f(m, n) to the source frequency f(m−M ２ , n) may be set to a frequency having the other frequency shift.

[0066] In another embodiment, the source frequency of the source radio frequency power HF in the phase period SP(m,n) may be determined as the frequency that minimizes the degree of reflection from two or more degrees of reflection (e.g., power levels Pr) obtained by using different source frequencies in corresponding phase periods SP(n) in two or more waveform periods CY preceding the waveform period CY(m). The frequency that minimizes the degree of reflection may be determined by a least-squares method using each of the different source frequencies and the corresponding degrees of reflection.

[0067] [Second Feedback]

[0068] The second feedback will be described below. In the following description, the pulse period P Ｐ (k) is the number of pulse periods P in each pulse period sequence Ｐ , and the waveform period CY(m) represents the kth pulse period of the plurality of pulse periods P Ｐ In addition, the waveform period CY(k, m) represents the m-th waveform period among the plurality of waveform periods CY(1) to CY(M) in each of the pulse period sequences. Ｐ The phase period SP(n) represents the mth waveform period in each pulse period sequence. Ｐ In each of the plurality of waveform periods CY, a phase period SP(m,n) represents the n-th phase period among the plurality of phase periods SP(1) to SP(N). In addition, a phase period SP(m,n) represents the n-th phase period in the waveform period CY(m). In addition, a phase period SP(k,m,n) represents the n-th phase period in the waveform period CY(m). In addition, a phase period SP(k,m,n) represents the n-th phase period in the waveform period CY(m). Ｐ represents the nth phase period in the waveform period CY(m) in (k).

[0069] In the second feedback, the high frequency power supply 31 adjusts the source frequency f(k, m, n) in response to the change in the degree of reflection of the source high frequency power HF. In the second feedback, the degree of reflection is determined in the same manner as in the first feedback. In the second feedback, the change in the degree of reflection occurs in two or more pulse periods P within each pulse period sequence. Ｐ In each pulse period sequence, two or more pulse periods P are identified by using different source frequencies of the source high frequency power HF in corresponding phase periods SP(n) in the waveform period CY(m). Ｐ Each of these has a pulse period P Ｐ (k) is the preceding pulse period.

[0070] In the second feedback, two or more pulse periods P Ｐ By using different source frequencies in the same phase period within the same waveform cycle, it is possible to identify the relationship between a change in source frequency (frequency shift) and a change in the degree of reflection of the source RF power. Therefore, the second feedback can adjust the source frequency used in the phase period SP(k,m,n) in response to the change in the degree of reflection so as to reduce the degree of reflection. Also, the second feedback can adjust the source frequency used in the multiple pulse periods P(k,m,n) in each pulse period sequence. Ｐ In each of the plurality of waveform periods CY in each of the waveform periods CY, it is possible to reduce the degree of reflection at high speed.

[0071] In each pulse period sequence, the pulse period P Ｐ (k) Two or more preceding pulse periods P Ｐ is (k-K １ )th pulse period P Ｐ (k-K １ ) and (k-K ２ )th pulse period P Ｐ (k-K ２ ) where K １ and K. ２ Is, K １ >K ２ is a natural number that satisfies.

[0072] In one embodiment, the pulse period P Ｐ (k-K １ ) is the pulse period P Ｐ (k-2). Pulse period P Ｐ (k-K ２ ) is the pulse period P Ｐ (k-K １ ) and in one embodiment, the pulse period P Ｐ (k-1). That is, in one embodiment, K ２ , K. １ are 1 and 2, respectively.

[0073] The high frequency power supply 31 is ２ , m, n) at source frequency f(k−K ２ , m, n), during the phase period SP(k−K １ , m, n) from the source frequency in the phase period SP(k, m, n). Here, f(k, m, n) represents the source frequency of the source high frequency power HF used in the phase period SP(k, m, n). f(k, m, n) is given by f(k, m, n) = f(k-K ２ ,m,n)+Δ(k,m,n), where Δ(k,m,n) represents the amount of frequency shift. One frequency shift is either a frequency decrease or a frequency increase. If one frequency shift is a frequency decrease, Δ(k,m,n) has a negative value. If one frequency shift is a frequency increase, Δ(k,m,n) has a positive value.

[0074] In the second feedback, the source frequency f(k−K ２ If the degree of reflection decreases when the source frequency f(k, m, n) is used, the high frequency power supply 31 changes the source frequency f(k−K ２ , m, n) to a frequency with one frequency shift. For example, one frequency shift results in a power level Pr(k−K ２ , m, n) is the power level Pr(k−K １ , m, n), the high frequency power supply 31 reduces the source frequency f(k, m, n) to the source frequency f(k−K２ , m, n), where Pr(k, m, n) represents the power level Pr of the reflected wave of the source high frequency power HF in the phase period SP(k, m, n).

[0075] In the second feedback, the source frequency f(k−K ２ , m, n), the degree of reflection may increase. For example, the power level Pr(k−K ２ , m, n) is the power level Pr(k−K １ In this case, the high frequency power supply 31 may increase the source frequency f(k, m, n) to the source frequency f(k−K ２ , m, n) may be set to a frequency having a frequency shift other than that.

[0076] Alternatively, in each pulse period sequence, the source frequency f(k,m,n) is Ｐ (k) Two or more preceding pulse periods P Ｐ The frequency that minimizes the degree of reflection may be determined from two or more degrees of reflection (e.g., power levels Pr) obtained by using different source frequencies of the source radio frequency power HF in corresponding phase periods SP(n) within the waveform period CY(m). The frequency that minimizes the degree of reflection may be determined by a least squares method using each of the different source frequencies and the corresponding degrees of reflection.

[0077] Reference is now made to Figures 7(a), 7(b), and 7(c), each of which illustrates a pulse period within a pulse period sequence associated with a plasma processing apparatus according to one exemplary embodiment.

[0078] The number of pulse periods P Ｐ From the first to the K ａ th pulse period P Ｐ (1) ~P Ｐ (K ａ) where K ａ is a natural number equal to or greater than 2. The high frequency power supply 31 operates during the pulse period P Ｐ (1) ~P Ｐ (K ａ ) the first to Mth waveform periods CY included in each of the ａ th waveform period CY(1) to CY(M ａ ) may use a frequency set registered in the corresponding frequency table. Ｐ (1) ~P Ｐ (K ａ ) in each of the first to M ａ th waveform period CY(1) to CY(M ａ In a plurality of phase periods SP in each of the phase periods SP, a plurality of frequencies included in a frequency set registered in the corresponding frequency table are used as source frequencies.

[0079] The high frequency power supply 31 generates a pulse period P Ｐ (1) ~P Ｐ (K ａ ), among the plurality of waveform periods CY, ａ ) in each pulse period sequence, the high frequency power supply 31 may perform the first feedback. Ｐ (1) ~P Ｐ (K ａ ) included in each of the waveform periods CY(M ａ The first feedback may be performed in CY(M+1) to CY(M).

[0080] In one embodiment, the number of pulse periods P Ｐ (K ａ +1) to K ｂ th pulse period P Ｐ (K ａ +1) ~ P Ｐ (K), where K is the final pulse period P in each pulse period sequence. Ｐ is a natural number that represents the order of

[0081] The high frequency power supply 31 generates a pulse period P Ｐ (K ａ +1) ~ P Ｐ (K) ｂ th waveform period CY(1) to CY(M ｂ ), the second feedback may be performed. ｂ is a natural number. The high frequency power supply 31 generates a pulse period P Ｐ (K ａ +1) ~ P Ｐ In each of (K), the waveform period CY(M ｂ ) in each pulse period sequence, the high frequency power supply 31 may perform the first feedback. Ｐ (K ａ +1) ~ P Ｐ (K) ｂ The first feedback may be performed in CY(M+1) to CY(M).

[0082] 8, which is a flow chart of a plasma processing method according to one exemplary embodiment. The plasma processing method shown in FIG. 8 (hereinafter referred to as "method MT") can be performed using a plasma processing apparatus 1.

[0083] 8, the method MT starts with step STp, in which a substrate W is provided on a substrate support 11 in a chamber 10.

[0084] In the method MT, as described above with respect to the plasma processing apparatus 1, a plurality of different processing conditions are used as processing conditions for plasma processing on the substrate W in a plurality of processing periods.

[0085] In one embodiment, step STa is performed in a first processing period. In step STa, a first plasma process is performed under first processing conditions. The first processing conditions include supplying a first processing gas into the chamber 10, from which plasma is generated. Step STa may be performed only once. Alternatively, step STa may be repeated. That is, pulse EBP may be repeatedly supplied in a first pulse period sequence consisting of repeated first processing periods. When step STa is repeated, it is determined in step STJA whether a stop condition is satisfied. In step STJA, the stop condition is satisfied when the number of repetitions of step STa reaches a predetermined number. If it is determined that the stop condition is not satisfied in step STJA, step STa is performed again. If it is determined that the stop condition is satisfied in step STJA, the repetition of step STa ends.

[0086] In one embodiment, step STb is performed in a second processing period. In step STb, a second plasma process is performed under second processing conditions. The second processing conditions include supplying a second processing gas into the chamber 10 from which plasma is generated. The second processing gas is a processing gas different from the first processing gas. Step STb may be performed only once. Alternatively, step STb may be repeated. That is, pulse EBP may be repeatedly supplied in a second pulse period sequence consisting of repeated second processing periods. When step STb is repeated, it is determined in step STJB whether a stop condition is satisfied. In step STJB, the stop condition is satisfied when the number of repetitions of step STb reaches a predetermined number. If it is determined in step STJB that the stop condition is not satisfied, step STb is performed again. If it is determined in step STJB that the stop condition is satisfied, the repetition of step STb ends.

[0087] In the method MT, a cycle including the steps STa and STb may be repeated. In this case, it is determined in the step STJZ whether or not the termination condition is satisfied. In the step STJZ, the termination condition is satisfied when the number of repetitions of the cycle reaches a predetermined number. If it is determined in the step STJZ that the termination condition is not satisfied, the cycle is performed again. If it is determined in the step STJZ that the stop condition is satisfied, the repetition of the cycle ends.

[0088] The method MT may include three or more steps of performing plasma processing on the substrate W. The three or more steps include step STa and step STb. The three or more steps are performed in three or more processing periods, respectively. In the three or more processing periods, as described above, three or more processing conditions different from one another are used as processing conditions for the plasma processing on the substrate W, respectively. A cycle of the method MT may include these three or more steps.

[0089] In the method MT, during a first processing period, a plurality of frequencies included in a first frequency set are used as source frequencies for each of a plurality of phase periods SP in a waveform period CY of the electrical bias EB. The first frequency set is determined so as to suppress the degree of reflection of the source high frequency power HF from the load during the first processing period. Furthermore, during a second processing period, a plurality of frequencies included in a second frequency set different from the first frequency set are used as source frequencies for each of a plurality of phase periods SP in the waveform period CY of the electrical bias EB. The second frequency set is determined so as to suppress the degree of reflection of the source high frequency power HF from the load during the second processing period. In this way, in the method MT, a plurality of frequency sets different from each other are used in each of the above-mentioned plurality of processing periods.

[0090] 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.

[0091] In other embodiments, the plasma processing apparatus may be an inductively coupled plasma processing apparatus, an ECR plasma processing apparatus, a helicon wave excited plasma processing apparatus, or a surface wave plasma processing apparatus. In any of these plasma processing apparatuses, a source high frequency power HF is used to generate the plasma, and the source frequency of the source high frequency power HF is adjusted as described above with respect to the plasma processing apparatus 1.

[0092] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E9] below.

[0093] a bias power supply electrically coupled to the substrate support and configured to generate an electric bias; wherein the radio frequency power supply is configured to: use, during a first processing period in which first processing conditions are applied, the source radio frequency power having a plurality of frequencies included in a first frequency set determined to suppress a degree of reflection of the source radio frequency power from a load; and use, during a second processing period in which second processing conditions are applied, the source frequencies having a plurality of frequencies included in a second frequency set determined to suppress a degree of reflection of the source radio frequency power from a load, the source frequencies being different from the first frequency set;

[0094] In the embodiment of [E1], the set of frequencies determined to suppress the degree of reflection of the source high frequency power from the load during a plurality of phase periods within a waveform period of the electrical bias is selected in accordance with at least the process gas, thereby making it possible to reduce the degree of reflection of the source high frequency power during a plurality of phase periods within a waveform period of the electrical bias in each of two or more periods in which different process gases are used.

[0095] [E2] The plasma processing apparatus according to [E1], wherein the electric bias is a voltage pulse sequence, the voltage pulse sequence including voltage pulses generated periodically at time intervals equal to the time length of the waveform period, and each of the first processing condition and the second processing condition further includes at least one of a power level of the source high frequency power, a level of the electric bias, a duty ratio of the voltage pulse of the electric bias in the waveform period, a bias frequency which is the reciprocal of the waveform period, and a pressure within the chamber.

[0096] [E3] The plasma processing apparatus according to [E1], wherein the electric bias is a bias high frequency power having the waveform period, and each of the first processing condition and the second processing condition further includes at least one of a power level of the source high frequency power, a level of the electric bias, a bias frequency that is the reciprocal of the waveform period, and a pressure in the chamber.

[0097] [E4] The plasma processing apparatus according to any one of [E1] to [E3], wherein the plurality of frequencies of the first frequency set are registered in a first frequency table prepared in advance in a memory unit of the plasma processing apparatus, and the plurality of frequencies of the second frequency set are registered in a second frequency table prepared in advance in the memory unit.

[0098] [E5] The plasma processing apparatus according to any one of [E1] to [E4], wherein the high frequency power supply is configured to adjust the source frequency for an nth phase period in an mth waveform period of the electric bias in each of the first processing period and the second processing period according to a change in the degree of reflection of the source high frequency power when a different frequency is used as the source frequency for the nth phase period in two or more waveform periods of the electric bias preceding the mth waveform period.

[0099] [E6] The plasma processing apparatus according to any one of [E1] to [E5], wherein the bias power supply is configured to supply a pulse of the electrical bias in each of a plurality of pulse periods that are repetitions of the first processing period included in a first pulse period sequence, and to supply a pulse of the electrical bias in each of a plurality of pulse periods that are repetitions of the second processing period included in a second pulse period sequence.

[0100] [E7] The plasma processing apparatus according to [E6], wherein the high frequency power supply is configured to adjust the source frequency for an nth phase period in an mth waveform period in a kth pulse period in each of the first pulse period sequence and the second pulse period sequence according to a change in the degree of reflection of the source high frequency power when a different frequency is used as the source frequency for the nth phase period in the mth waveform period in two or more pulse periods preceding the kth pulse period.

[0101] [E8] The plasma processing apparatus according to [E6] or [E7], wherein the high frequency power supply is configured to supply a pulse of the source high frequency power in each of the plurality of pulse periods included in the first pulse period sequence, and to supply a pulse of the source high frequency power in each of the plurality of pulse periods included in the second pulse period sequence.

[0102] [E9] A method of plasma processing comprising: preparing a substrate on a substrate support in a chamber of a plasma processing apparatus; performing a first plasma processing on the substrate using first processing conditions including supplying a first processing gas from a gas supply into the chamber during a first processing period; and performing a second plasma processing on the substrate using first processing conditions including supplying a second processing gas from a gas supply into the chamber during a second processing period; wherein during each of the first processing period and the second processing period, a source radio frequency power for generating plasma is supplied, and an electric bias is supplied to the substrate support from a bias power supply; and during the first processing period, a plurality of frequencies included in a first frequency set determined to suppress a degree of reflection of the source radio frequency power from a load are used as source frequencies of the source radio frequency power for each of a plurality of phase periods in a waveform cycle of the electric bias, In the second processing period, a plurality of frequencies included in a second frequency set different from the first frequency set and determined to suppress a degree of reflection of the source high frequency power from the load are used as the source frequency for each of the plurality of phase periods within the waveform period of the electrical bias.

[0103] 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.

[0104] 1... plasma processing apparatus, 10... chamber, 11... substrate support part, 31... high frequency power supply, 32... bias power supply

Claims

1. Chamber and, A substrate support portion provided within the chamber, A gas supply unit configured to supply gas into the chamber, A high-frequency power supply configured to supply source high-frequency power to generate plasma from gas in the chamber, A bias power supply, which is electrically coupled to the substrate support and configured to generate an electrical bias, Equipped with, The aforementioned high-frequency power supply is In a first processing period in which first processing conditions are applied, including supplying a first processing gas into the chamber from the gas supply unit, a plurality of frequencies included in a first frequency set determined to suppress the degree of reflection of the source high-frequency power from the load are used as the source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias. In a second processing period in which a second processing condition is applied, which includes supplying a second processing gas into the chamber from the gas supply unit, a plurality of frequencies included in the second frequency set, which is different from the first frequency set and is determined to suppress the degree of reflection of the source high-frequency power from the load, are used as the source frequencies for each of the plurality of phase periods within the waveform period of the electrical bias. It is structured in such a way. Plasma processing equipment.

2. The electrical bias is a voltage pulse sequence, which includes voltage pulses that are generated periodically at time intervals equal to the time length of the waveform period. Each of the first and second processing conditions further includes at least one of the following: the power level of the source high-frequency power, the level of the electrical bias, the duty cycle of the voltage pulse of the electrical bias in the waveform period, the bias frequency which is the reciprocal of the waveform period, and the pressure in the chamber. The plasma processing apparatus according to claim 1.

3. The electrical bias is a bias high-frequency power having the waveform period, Each of the first and second processing conditions further includes at least one of the power level of the source high-frequency power, the level of the electrical bias, the bias frequency which is the reciprocal of the waveform period, and the pressure in the chamber. The plasma processing apparatus according to claim 1.

4. The plurality of frequencies in the first frequency set are registered in a first frequency table prepared in advance in the storage unit of the plasma processing apparatus. The plurality of frequencies in the second frequency set are registered in a second frequency table prepared in advance in the storage unit. The plasma processing apparatus according to claim 1.

5. The high-frequency power supply is configured to adjust, in each of the first and second processing periods, the source frequency for the nth phase period within the mth waveform period of the electrical bias in accordance with the change in the degree of reflection of the source high-frequency power when a different frequency is used as the source frequency for the nth phase period within two or more waveform periods of the electrical bias preceding the mth waveform period. The plasma processing apparatus according to claim 1.

6. The plasma processing apparatus according to claim 5, wherein the high-frequency power supply is configured such that when the degree of reflection decreases by applying a frequency shift of either a decrease or an increase to the source frequency in the nth phase period within the (m-M2)th waveform period of the two or more waveform periods, the source frequency in the nth phase period within the mth waveform period is set to a frequency having the one of the frequency shifts with respect to the source frequency in the nth phase period within the (m-M2)th waveform period, where M1 and M2 are natural numbers satisfying M1 > M2.

7. The aforementioned bias power supply is In each of the plurality of pulse periods which are repetitions of the first processing period included in the first pulse period sequence, the pulse of the electrical bias is supplied. In each of the plurality of pulse periods which are repetitions of the second processing period included in the second pulse period sequence, the pulses of the electrical bias are supplied. The plasma processing apparatus according to claim 1, configured as described above.

8. The plasma apparatus according to claim 7, wherein the bias power supply is configured to set the level of the pulses of the electrical bias supplied in each of the plurality of pulse periods included in the first pulse period sequence to a level different from the level of the pulses of the electrical bias supplied in each of the plurality of pulse periods included in the second pulse period sequence.

9. The plasma processing apparatus according to claim 7, wherein the bias power supply is configured to set the ON duration of the electrical bias pulse supplied in each of the plurality of pulse periods included in the first pulse period sequence to a duration different from the ON duration of the electrical bias pulse supplied in each of the plurality of pulse periods included in the second pulse period sequence.

10. The plasma apparatus according to claim 7, wherein the high-frequency power supply is configured to adjust, in each of the first pulse period sequence and the second pulse period sequence, the source frequency for the nth phase period in the mth waveform period within the kth pulse period in accordance with the change in the degree of reflection of the source high-frequency power when a different frequency is used as the source frequency for the nth phase period in the mth waveform period within two or more pulse periods preceding the kth pulse period.

11. The plasma processing apparatus according to claim 10, wherein the high-frequency power supply is configured such that when the degree of reflection decreases by applying a frequency shift of either a decrease or an increase to the source frequency in the nth phase period in the mth waveform period in the (k-K1) pulse period among the two or more pulse periods, the source frequency in the nth phase period in the mth waveform period in the (k-K2) pulse period has a frequency shift of the one of the above with respect to the source frequency in the nth phase period in the mth waveform period in the (k-K2) pulse period, where K1 and K2 are natural numbers satisfying K1 > K2.

12. The aforementioned high-frequency power supply is In each of the plurality of pulse periods included in the first pulse period sequence, a pulse of the source high-frequency power is supplied. In each of the plurality of pulse periods included in the second pulse period sequence, the pulse of the source high-frequency power is supplied. The plasma processing apparatus according to claim 7, configured as described above.

13. The plasma processing apparatus according to claim 12, wherein the high-frequency power supply is configured to set the power level of the pulses of the source high-frequency power supplied in each of the plurality of pulse periods included in the first pulse period sequence to a level different from the power level of the pulses of the source high-frequency power supplied in each of the plurality of pulse periods included in the second pulse period sequence.

14. The plasma processing apparatus according to claim 12, wherein the high-frequency power supply is configured to set the ON duration of the pulses of the source high-frequency power supplied in each of the plurality of pulse periods included in the first pulse duration sequence to a duration different from the ON duration of the pulses of the source high-frequency power supplied in each of the plurality of pulse periods included in the second pulse duration sequence.

15. The plasma processing apparatus according to any one of claims 1 to 14, further comprising a sensor configured to output a parameter relating to the degree of at least one reflection in the power supply path of the source high-frequency power.

16. The plasma processing apparatus according to claim 15, wherein the sensor includes a directional coupler configured to output the power level of the reflected wave returned from the load of the high-frequency power supply.

17. The plasma processing apparatus according to claim 15, wherein the sensor is configured to measure the voltage and current of the source high-frequency power in the power supply path.

18. The plasma processing apparatus according to claim 15, wherein the at least one parameter relating to the degree of reflection includes at least one of the power level of the reflected wave of the source high-frequency power, the ratio of the power level of the reflected wave to the output power level of the source high-frequency power, the phase difference between the voltage and current of the source high-frequency power, and the load-side impedance of the high-frequency power supply.

19. A step of preparing a substrate on a substrate support part inside the chamber of a plasma processing apparatus, A step of performing a first plasma treatment on the substrate using first processing conditions, which include supplying a first processing gas from a gas supply unit into the chamber during a first processing period, A step of performing a second plasma treatment on the substrate using second processing conditions, which include supplying a second processing gas from a gas supply unit into the chamber during a second processing period. Includes, During each of the first and second processing periods, source high-frequency power for generating plasma is supplied, and an electrical bias is supplied from the bias power supply to the substrate support portion. During the first processing period, a plurality of frequencies included in a first frequency set determined to suppress the degree of reflection of the source high-frequency power from the load are used as the source frequency of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias. During the second processing period, a plurality of frequencies included in the second frequency set, which is different from the first frequency set and is determined to suppress the degree of reflection of the source high-frequency power from the load, are used as the source frequency for each of the plurality of phase periods within the waveform period of the electrical bias. Plasma treatment method.

20. A program for causing a control unit of a plasma processing apparatus to perform control of the plasma processing apparatus, wherein the program causes the control unit to: A step of performing a first plasma treatment on a substrate on a substrate support in a chamber using first treatment conditions, which include supplying a first treatment gas from a gas supply unit into the chamber of the plasma treatment device during a first treatment period. A step of performing a second plasma treatment on the substrate on the substrate support in the chamber using second processing conditions, which include supplying a second processing gas from the gas supply unit into the chamber during a second processing period. To execute, and, During each of the first and second processing periods, source high-frequency power for generating plasma is supplied to the high-frequency power supply, and an electrical bias is supplied to the substrate support portion to the bias power supply. During the first processing period, a plurality of frequencies included in a first frequency set determined to suppress the degree of reflection of the source high-frequency power from the load are used as the source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias. During the second processing period, a second frequency set different from the first frequency set, and which is determined to suppress the degree of reflection of the source high-frequency power from the load, is used as the source frequency for each of the multiple phase periods within the waveform period of the electrical bias. To execute the process program.