Plasma processing method and plasma processing apparatus

Abstract

The present invention discloses a plasma processing method comprising a step (a) for generating plasma in a chamber of a plasma processing apparatus. The plasma processing apparatus has a substrate support part that is provided in the chamber, and the substrate support part supports a substrate that is placed thereon. The plasma processing method further comprises a step (b) for applying a voltage pulse from a bias power source to a bias electrode of the substrate support part in order to draw ions from plasma to the substrate. The plasma processing method further comprises a step (c) for repeating step (b). In step (c), the length of duration of the voltage pulse is changed so that the potential of the substrate is changed.

Description

Plasma processing method and plasma processing apparatus

[0001] SUMMARY OF THE INVENTION An exemplary embodiment of the present disclosure relates to a plasma processing method and a plasma processing apparatus.

[0002] A plasma processing apparatus is used for plasma processing of a substrate. The plasma processing apparatus includes a chamber and a substrate-holding electrode. The substrate-holding electrode is provided in the chamber. The substrate-holding electrode holds a substrate placed on its main surface. One type of such a plasma processing apparatus is described in Patent Document 1 listed below.

[0003] The plasma processing apparatus described in Patent Document 1 further includes a radio frequency generator and a DC negative pulse generator. The radio frequency generator applies a radio frequency voltage to a substrate holding electrode. In the plasma processing apparatus described in Patent Document 1, the radio frequency voltage is alternately switched on and off. In addition, in the plasma processing apparatus described in Patent Document 1, a DC negative pulse voltage is applied to the substrate holding electrode from the DC negative pulse generator in accordance with the timing of the radio frequency voltage being turned on and off.

[0004] JP 2009-187975 A

[0005] The present disclosure provides techniques for changing the potential of a substrate in a plasma processing apparatus.

[0006] In one exemplary embodiment, a plasma processing method is provided. The plasma processing method includes step (a) of generating a plasma in a chamber of a plasma processing apparatus. The plasma processing apparatus has a substrate support disposed in the chamber, the substrate support supporting a substrate placed thereon. The plasma processing method further includes step (b) of applying a voltage pulse from a bias power supply to a bias electrode of the substrate support to attract ions from the plasma to the substrate. The plasma processing method further includes step (c) of repeating step (b). In step (c), the duration of the voltage pulse is changed to change the potential of the substrate.

[0007] According to one exemplary embodiment, a technique is provided for altering the potential of a substrate in a plasma processing system.

[0008] FIG. 5 is a flow chart of a plasma processing method according to an exemplary embodiment; FIG. 6 is a diagram for explaining an example of the configuration of a plasma processing system; FIG. 7 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus; and FIG. 8 is a diagram showing an example of the configuration of a power supply system in a plasma processing apparatus according to an exemplary embodiment. Each of FIGS. 5(a) and 5(b) is a timing chart of an example related to a plasma processing apparatus according to an exemplary embodiment. Each of FIGS. 6(a) and 6(b) is a timing chart of an example related to a plasma processing apparatus according to an exemplary embodiment. FIG. 7 is a timing chart of yet another example related to a plasma processing apparatus according to an exemplary embodiment. A diagram showing another example of the configuration of a power supply system in a plasma processing apparatus according to an exemplary embodiment. A partially enlarged cross-sectional view of another example of a substrate support.

[0009] Various exemplary embodiments are described below.

[0010] In one exemplary embodiment, a plasma processing method is provided. The plasma processing method includes step (a) of generating a plasma in a chamber of a plasma processing apparatus. The plasma processing apparatus has a substrate support disposed in the chamber, the substrate support supporting a substrate placed thereon. The plasma processing method further includes step (b) of applying a voltage pulse from a bias power supply to a bias electrode of the substrate support to attract ions from the plasma to the substrate. The plasma processing method further includes step (c) of repeating step (b). In step (c), the duration of the voltage pulse is changed to change the potential of the substrate.

[0011] There is a delay between when the voltage pulse is output from the bias power supply and when the substrate potential reaches the maximum potential corresponding to the set voltage level of the voltage pulse. Therefore, the substrate potential depends on the duration of the voltage pulse. Therefore, according to the above embodiment, it is possible to change the substrate potential by changing the duration of the voltage pulse.

[0012] In one exemplary embodiment, the period during which step (c) is performed may include a plurality of ON periods and a plurality of OFF periods alternating with the plurality of ON periods, wherein during each of the plurality of ON periods, a voltage pulse is repeatedly applied from the bias power supply to the bias electrode, and the duration of the voltage pulse is varied to change the potential of the substrate, and during each of the plurality of OFF periods, application of the voltage pulse from the bias power supply to the bias electrode is stopped.

[0013] In one exemplary embodiment, the duration of the voltage pulse may be increased in each of the ON periods, thereby suppressing abrupt changes in plasma impedance during each of the ON periods, thereby reducing reflections of the source RF power used to generate the plasma.

[0014] In one exemplary embodiment, the duration of the voltage pulse may be adjusted in each of the multiple ON periods so that the variance in the emission intensity or distribution of emission intensity within the chamber approaches a predetermined value.

[0015] In one exemplary embodiment, the period during which step (c) is performed may include a plurality of ON periods and a plurality of OFF periods alternating with the plurality of ON periods. During each of the plurality of ON periods, a voltage pulse is repeatedly applied from the bias power supply to the bias electrode. During each of the plurality of OFF periods, application of the voltage pulse from the bias power supply to the bias electrode is stopped. The duration of the voltage pulse in at least one of the plurality of ON periods may be set to a value different from the duration of the voltage pulse in another of the plurality of ON periods. According to this embodiment, the potential of the substrate can be changed as the plasma processing of the substrate progresses.

[0016] In one exemplary embodiment, electrical bias energy may be applied periodically to the bias electrode in step (c). The electrical bias energy includes voltage pulses and has a waveform period. In step (c), the duration of the voltage pulses may be changed by changing the duty ratio of the voltage pulses in the waveform period.

[0017] In one exemplary embodiment, the plasma processing method may further include adjusting a source frequency of the source radio frequency power supplied to generate the plasma so as to reduce a degree of reflection of the source radio frequency power.

[0018] In one exemplary embodiment, the source frequency may be adjusted during each of a plurality of phase periods within a waveform period of the electrical biasing energy comprising the voltage pulse.

[0019] In one exemplary embodiment, steps (a), (b), and (c) may be performed to etch a film on a substrate.

[0020] In one exemplary embodiment, in step (c), the set voltage level of the voltage pulse in the bias power supply may further be changed.

[0021] In another exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a plasma generating unit, and a bias power supply. The substrate support is disposed within the chamber. The plasma generating unit is configured to generate a plasma within the chamber. The bias power supply is configured to repeatedly apply voltage pulses to a bias electrode of the substrate support to attract ions from the plasma to a substrate on the substrate support. The bias power supply is configured to vary the duration of the voltage pulses to vary the potential of the substrate upon repeated application of the voltage pulses to the bias electrode.

[0022] 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.

[0023] 1 is a flow chart of a plasma processing method according to one example embodiment. The plasma processing method shown in FIG. 1 (hereinafter referred to as "method MT") is used for plasma processing, e.g., etching, on a substrate. Method MT is performed using a plasma processing apparatus.

[0024] FIG. 2 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 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.

[0025] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated 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), surface wave plasma (SWP), or the like.

[0026] 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).

[0027] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 3 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0028] 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.

[0029] 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. Thus, the central region 111a includes a substrate support surface for supporting the substrate W, and the annular region 111b includes a ring support surface for supporting the ring assembly 112.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Hereinafter, reference will be made to FIG. 4 together with FIG. 3. FIG. 4 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 source high frequency power RF. The source high frequency power RF has a source frequency f ＲＦThat is, the source radio frequency power RF has a frequency equal to the source frequency f ＲＦ The source frequency f ＲＦ The frequency of the RF power source 31 may be within a range of 10 MHz to 150 MHz. The RF power source 31 is electrically connected to the RF electrode via a matching box 33 and is configured to supply source RF power RF to the RF electrode. The RF electrode may be provided within the substrate support 11. The RF electrode may be at least one electrode provided within the conductive member or ceramic member 1111a of the base 1110. Alternatively, the RF electrode may be an upper electrode. When the source RF power RF is supplied to the RF electrode, plasma is generated from the gas within the chamber 10.

[0037] The matching circuit 33 has a variable impedance. The variable impedance of the matching circuit 33 is set to reduce reflection of the source high frequency power RF from the load. The matching circuit 33 can be controlled by, for example, the control unit 2.

[0038] 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 ＲＦ 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.

[0039] 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 RF. The gain of the amplifier 31a is specified to the high frequency power supply 31 by the control unit 2. Note that the high frequency power supply 31 does not need to include the D / A converter 31c. In this case, the output of the signal generator 31g is connected to the input of the amplifier 31a, and the amplifier 31a amplifies the high frequency signal from the signal generator 31g to generate source high frequency power RF.

[0040] 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 electric bias energy BE 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 energy BE is supplied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0041] 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 4. The signal generator 32g generates a bias signal having a specified waveform. The signal generator 32g may be comprised of a programmable processor or a programmable logic device processor such as an FPGA.

[0042] 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 electrical bias energy BE. 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 amplifies the bias signal from the signal generator 32g to generate electrical bias energy BE.

[0043] Reference will now be made to Figures 5(a), 5(b), 6(a), 6(b), and 7, along with Figures 3 and 4. Figures 5(a), 5(b), 6(a), 6(b), and 7 each show an example timing chart related to a plasma processing apparatus according to an exemplary embodiment. Figures 5(a), 6(a), and 7 each show a timing chart of pulses of source high frequency power RF and pulses of electrical bias energy BE. In Figures 5(a), 6(a), and 7, ON of source high frequency power RF indicates that pulses of source high frequency power RF are being supplied, and OFF of source high frequency power RF indicates that the supply of source high frequency power RF is stopped. 5(a), 6(a), and 7, ON of the electric bias energy BE indicates that a pulse of the electric bias energy BE is being supplied, and OFF of the electric bias energy BE indicates that the supply of the electric bias energy BE is stopped. Each of (b) of FIG. 5 and (b) of FIG. 6 shows the waveform of the voltage pulse PV of the electric bias energy BE, the source frequency, and the potential of the substrate W. Furthermore, FIG. 7 shows the duty ratio DR of the voltage pulse PV of the electric bias energy BE and the set voltage level VB of the voltage pulse PV in the bias power supply 32.

[0044] The electrical bias energy BE includes a voltage pulse PV. The waveform of the voltage pulse PV may be a square wave, a triangular wave, or any other waveform. The polarity of the voltage pulse PV is set so as to generate a potential difference between the substrate W and the plasma, thereby attracting ions from the plasma to the substrate W. The voltage pulse PV may be a negative voltage pulse or a negative DC voltage pulse.

[0045] The bias power supply 32 is configured to repeatedly supply electric bias energy BE to the bias electrode. That is, the bias power supply 32 is configured to repeatedly apply a voltage pulse PV to the bias electrode. The bias power supply 32 is also configured to repeatedly supply pulses of electric bias energy BE to the bias electrode. That is, pulses of electric bias energy BE are supplied to the bias electrode during multiple ON periods PP. The multiple ON periods PP appear sequentially. Note that in the following description and drawings, ON period PP(k) represents the kth ON period among the multiple ON periods PP. In each of the multiple ON periods PP, electric bias energy BE is repeatedly supplied to the bias electrode. That is, in each of the multiple ON periods PP, a voltage pulse PV is repeatedly applied to the bias electrode. The supply of pulses of electric bias energy BE, i.e., the repeated application of voltage pulses PV to the bias electrode, is stopped during an OFF period. The OFF period is the period between two ON periods PP that appear sequentially.

[0046] In one embodiment, the bias power supply 32 may be configured to periodically apply electrical bias energy BE having a waveform period CY to the bias electrode during each of the multiple ON periods PP. That is, the bias power supply 32 may periodically apply a voltage pulse PV to the bias electrode during each of the multiple ON periods PP at a time interval equal to the time length of the waveform period CY. Each of the multiple waveform periods CY is defined by a bias frequency. The bias frequency is, for example, equal to or greater than 50 kHz and equal to or less than 27 MHz. The time length of each waveform period CY is the reciprocal of the bias frequency.

[0047] The bias power supply 32 changes the duration of the voltage pulse PV when the voltage pulse PV is repeatedly applied to the bias electrode to change the potential of the substrate W. In one embodiment, the bias power supply 32 changes the duration of the voltage pulse PV by changing the duty ratio DR of the voltage pulse PV. The duty ratio DR is the percentage (%) of the waveform period CY that the duration of the voltage pulse PV occupies.

[0048] There is a delay between when the voltage pulse PV is output by the bias power supply 32 and when the potential of the substrate W reaches the maximum potential corresponding to the set voltage level of the voltage pulse PV. That is, if the duration of the voltage pulse PV is sufficiently long, the potential of the substrate W reaches the maximum potential corresponding to the set voltage level of the voltage pulse PV during the period when the voltage pulse PV is applied to the bias electrode. On the other hand, if the duration of the voltage pulse PV is short, the application of the voltage pulse PV ends before the potential of the substrate W reaches the maximum potential corresponding to the set voltage level of the voltage pulse PV. Therefore, if the duration of the voltage pulse PV is short, the potential of the substrate W reached during the period when the voltage pulse PV is applied to the bias electrode is lower than the maximum potential corresponding to the set voltage level of the voltage pulse PV. Thus, the potential of the substrate W depends on the duration of the voltage pulse PV. Therefore, according to the plasma processing apparatus 1, the potential of the substrate W can be changed by changing the duration of the voltage pulse PV.

[0049] In one embodiment, the bias power supply 32 may repeatedly apply a voltage pulse PV to the bias electrode during each of a plurality of ON periods PP, as shown in (b) of FIG. 5, and may vary the duration of the voltage pulse PV to vary the potential of the substrate W.

[0050] 5B, the bias power supply 32 may increase the duration of the voltage pulse PV when repeatedly applying the voltage pulse PV to the bias electrode in each of the multiple ON periods PP, thereby suppressing changes in the impedance of the plasma at the start of each of the multiple ON periods PP, thereby increasing the efficiency of coupling the source radio frequency power RF to the plasma.

[0051] In one embodiment, the bias power supply 32 may adjust the duration of the voltage pulse PV during the repeated application of the voltage pulse PV to the bias electrode during each of the multiple ON periods PP so that the variation in the emission intensity or distribution of emission intensity within the chamber 10 approaches a predetermined value. The emission intensity or variation in the distribution of emission intensity within the chamber 10 may be acquired by one or more optical emission spectrometers 50, as shown in FIG. 3 . For example, the bias power supply 32 reduces the duration of the voltage pulse PV when the emission intensity within the chamber 10 is lower than a predetermined value or when the variation in the distribution of emission intensity within the chamber 10 is greater than a predetermined value.

[0052] In one embodiment, as shown in FIG. 6B , the bias power supply 32 may set the duration of the voltage pulse PV in at least one of the plurality of ON periods PP to a value different from the duration of the voltage pulse PV in another ON period PP. For example, the bias power supply 32 may change the duration of the voltage pulse PV in the ON period PP as etching of the film on the substrate W progresses. Note that the duration of the voltage pulse PV may be constant in each of the plurality of ON periods PP. Alternatively, the duration of the voltage pulse PV in each of the plurality of ON periods PP may be changed until it reaches its final value. For example, the duration of the voltage pulse PV in each of the plurality of ON periods PP may be increased until it reaches its final value. Alternatively, the duration of the voltage pulse PV in each of the plurality of ON periods PP may be adjusted until it reaches its final value so as to reduce the variation in the emission intensity or emission intensity distribution in the chamber 10 to a predetermined value.

[0053] In one embodiment, the bias power supply 32 may change the set voltage level VB of the voltage pulse PV in addition to changing the duration of the voltage pulse PV. For example, as shown in FIG. 7, the bias power supply 32 may change the set voltage level VB for each of two or more sequentially occurring ON periods PP.

[0054] In one embodiment, the radio frequency power supply 31 may alternately turn on and off the source radio frequency power RF. That is, the radio frequency power supply 31 may repeatedly supply pulses of the source radio frequency power RF. The multiple periods during which the source radio frequency power RF pulses are supplied may coincide with the multiple ON periods PP. Alternatively, each of the multiple periods during which the source radio frequency power RF pulses are supplied may partially overlap with a corresponding ON period PP among the multiple ON periods PP. Alternatively, the radio frequency power supply 31 may continuously supply the source radio frequency power RF. In the following description, a period during which pulses of the source radio frequency power RF and the electrical bias energy BE are simultaneously supplied is referred to as an overlap period OP. In the plasma processing apparatus 1, multiple overlap periods OP appear sequentially. In the following description and drawings, an overlap period OP(k) represents the kth overlap period among the multiple overlap periods OP.

[0055] In one embodiment, the RF power source 31 may be configured to adjust the source frequency to reduce the degree of reflection of the source RF power RF in at least each of a plurality of overlapping periods OP. In one embodiment, the RF power source 31 may be configured to adjust the source frequency to reduce the degree of reflection of the source RF power RF in each of a plurality of phase periods SP in a waveform period CY of the electrical bias energy BE. The adjustment of the source frequency is performed by a first feedback and / or a second feedback, which will be described later.

[0056] The radio frequency power source 31 may modulate the power level of the source radio frequency power RF. For example, the radio frequency power source 31 may modulate the power level of the source radio frequency power RF in each of the multiple overlap periods OP. Alternatively, the radio frequency power source 31 may set the power level of the source radio frequency power RF in at least one overlap period of the multiple overlap periods OP to a level different from the power level of the source radio frequency power RF in another overlap period.

[0057] [First Feedback]

[0058] The first feedback will be described below. The first feedback is performed to adjust the source frequency in multiple phase periods SP in each of multiple consecutive waveform periods CY within the overlap period OP. 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 the multiple consecutive waveform periods CY. Phase period SP(n) represents the nth phase period among the phase periods SP(1) to SP(N). Furthermore, phase period SP(m,n) represents the nth phase period in waveform period CY(m).

[0059] The adjustment of the source frequency in the first feedback 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 RF in the phase period SP(m,n) in accordance with changes in the degree of reflection of the source high frequency power RF.

[0060] To determine the degree of reflection of the source radio frequency power RF, the plasma processing apparatus 1 may further include a sensor 35 and / or a sensor 36. The sensor 35 is configured to measure the power level Pr of the source radio frequency power RF reflected from the load. The sensor 35 includes, for example, a directional coupler. This directional coupler may be provided between the radio frequency power supply 31 and the matching box 33. The sensor 35 may further measure the power level Pf of the forward wave of the source radio frequency power RF. The power level Pr of the reflected wave measured by the sensor 35 is notified to the radio frequency power supply 31. In addition, the power level Pf of the forward wave may be notified from the sensor 35 to the radio frequency power supply 31.

[0061] 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. ＲＦ and current I ＲＦThe source radio frequency power RF is supplied to the radio frequency electrode via this power supply line. The sensor 36 may be provided between the radio frequency power supply 31 and the matching box 33. The voltage V ＲＦ and current I ＲＦ is notified to the high frequency power supply 31.

[0062] The high frequency power supply 31 generates a representative value from measurements taken during each of the multiple phase periods SP. The measurement value may be the power level Pr of the reflected wave acquired by the sensor 35. The measurement value may also be the ratio of the power level Pr of the reflected wave to the output power level of the source high frequency power RF (i.e., the reflectivity). The measurement value may be the voltage V acquired by the sensor 36 during each of the multiple phase periods SP. ＲＦ and current I ＲＦ 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. ＲＦ and current I ＲＦ 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 RF.

[0063] 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 two or more waveform periods CY prior to the waveform period CY(m).

[0064] 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 electrical bias energy BE is applied to the bias electrode of the substrate support 11.

[0065] 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.

[0066] 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 radio frequency power RF 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.

[0067] 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 RF in the phase period SP(m, n).

[0068] 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.

[0069] In another embodiment, the source frequency of the source radio frequency power RF in 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 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 frequencies and the corresponding degrees of reflection.

[0070] [Second Feedback]

[0071] The second feedback will be described below. In the following description, waveform period CY(m) represents the mth waveform period among the multiple waveform periods CY(1) to CY(M) in each of the multiple overlap periods OP. Furthermore, waveform period CY(k, m) represents the mth waveform period within the kth overlap period. Furthermore, phase period SP(n) represents the nth phase period among the multiple phase periods SP(1) to SP(N) in each of the multiple waveform periods CY in each of the multiple overlap periods OP. Furthermore, phase period SP(m, n) represents the nth phase period in waveform period CY(m). Furthermore, phase period SP(k, m, n) represents the nth phase period in waveform period CY(m) within the kth overlap period OP(k).

[0072] The adjustment of the source frequency of each of the multiple phase periods SP in each of the multiple waveform periods CY in each of the overlap periods OP(1) to OP(T-1) can be performed by the first feedback described above, where T is an integer greater than or equal to 3. Alternatively, the source frequency of each of the multiple phase periods SP in each of the multiple waveform periods CY in each of the overlap periods OP(1) to OP(T-1) can be set to a frequency registered in a table prepared in advance.

[0073] A second feedback may be used to adjust the source frequency of the source radio frequency power RF in overlap periods after the overlap period OP(T). In the second feedback, the radio frequency power supply 31 adjusts the source frequency f(k, m, n) in accordance with the change in the degree of reflection of the source radio frequency power RF. In the second feedback, the change in the degree of reflection is identified by using different source frequencies of the source radio frequency power RF in corresponding phase periods SP(n) in waveform periods CY(m) in two or more overlap periods OP before the overlap period OP(k).

[0074] The second feedback method uses different source frequencies in the same phase period within the same waveform cycle in each of two or more overlap periods OP, making it 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, the second feedback method 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. Furthermore, the second feedback method can quickly reduce the degree of reflection in each of the multiple waveform periods CY within each of the multiple overlap periods OP.

[0075] In one embodiment, two or more overlapping periods OP before an overlapping period OP(k) are (k−K １ )th overlap period OP(k−K １ ) and (k-K ２ )th overlap period OP(k−K ２ ) where K １ and K. ２ Is, K １ >K ２ is a natural number that satisfies

[0076] In one embodiment, the overlap period OP(k−K １ ) is the overlap period OP(k-2). ２ ) is the overlap period OP(k−K １ ), which in one embodiment is the overlap period OP(k-1). ２, K. １ are 1 and 2, respectively.

[0077] 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 phase period SP(k, m, n). Here, f(k, m, n) represents the source frequency of the source radio frequency power RF used in 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.

[0078] 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−K ２ , m, n), where Pr(k, m, n) represents the power level Pr of the reflected wave of the source high frequency power RF in the phase period SP(k, m, n).

[0079] 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−K２ , 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.

[0080] In another embodiment, the multiple overlapping periods OP are 1 to K ａ th overlap period OP(1) to OP(K ａ ) where K ａ is a natural number equal to or greater than 2. The high frequency power supply 31 operates during the overlap periods OP(1) to OP(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 be subjected to initial processing. ａ is a natural number. In the initial processing, the waveform periods CY(1) to CY(M ａ ) may be used, and the frequency sets included in the frequency set group may be different from each other. ａ A plurality of frequency sets may be used for each of the overlap periods OP(1) to OP(K), and these plurality of frequency sets may be different from each other. ａ ) in each of the first to M ａ th waveform period CY(1) to CY(M ａ In each of the phase periods SP in each of the phase periods SP, a plurality of frequencies included in the corresponding frequency set are used as the source frequency. The plurality of frequency sets and the plurality of frequency set groups may be stored in a storage unit of the control unit 2 or the high-frequency power supply 31.

[0081] The high frequency power supply 31 operates during the overlapping periods OP(1) to OP(K ａ ), among the plurality of waveform periods CY, ａ), the first feedback may be performed after the overlapping periods OP(1) to OP(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).

[0082] In one embodiment, the multiple overlapping periods OP are ａ +1) to K ｂ th overlap period OP(K ａ +1) ~ OP (K ｂ ) may further comprise: ｂ (K ａ +1), and K ｂ =K ａ +1 may be satisfied.

[0083] The high frequency power supply 31 operates during the overlap period OP(K ａ +1) ~ OP (K ｂ ) the first to Mth waveform periods CY included in each of the ｂ１ th waveform period CY(1) to CY(M ｂ１ ) may be subjected to the above initial processing. ｂ１ is a natural number. ｂ１ and M ａ is M ｂ１ <M ａ may be satisfied.

[0084] The high frequency power supply 31 operates during the overlap period OP(K ａ +1) ~ OP (K ｂ ) among the plurality of waveform periods CY included in each of (M ｂ１ +1)th to M ｂ２ th waveform period CY(M ｂ１ +1) ~ CY (M ｂ２ ), the second feedback may be performed. ｂ２ is M ｂ２ >M ｂ１ is a natural number that satisfies

[0085] The high frequency power supply 31 operates during the overlap period OP(K ａ +1) ~ OP (K ｂ ) for each waveform period CY(Mｂ２ ) after the overlap period OP(K ａ +1) ~ OP (K ｂ ) included in each of the waveform periods CY(M ｂ２ The first feedback may be performed in CY(M+1) to CY(M).

[0086] In addition, the high frequency power supply 31 is (K ｂ +1) to the last overlap period OP(K ｂ +1) to OP(K) from the first to M ｃ th waveform period CY(1) to CY(M ｃ ), the second feedback may be performed. ｃ is a natural number. The high frequency power supply 31 operates during the overlap period OP(K ｂ +1) to OP(K), the waveform period CY(M ｃ ) after the overlap period OP(K ｂ +1) to OP(K) ｃ The first feedback may be performed in CY(M+1) to CY(M).

[0087] In another embodiment, in the first feedback loop, the source frequency of the source radio frequency power RF in the phase period SP(k,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 of the source radio frequency power RF in corresponding phase periods SP(n) in two or more waveform periods CY prior to the waveform period CY(k,m) within the overlap period OP(k). The frequency that minimizes the degree of reflection may be determined by a least-squares method using each of the different frequencies and the corresponding degrees of reflection.

[0088] In the second feedback loop, the source frequency f(k, 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 of the source radio frequency power RF in corresponding phase periods SP(n) within waveform periods CY(m) in two or more overlap periods OP before the overlap period OP(k). The frequency that minimizes the degree of reflection may be determined by a least-squares method using each of the different frequencies and the corresponding degrees of reflection.

[0089] Referring again to FIG. 1 , the method MT will be described. In the following description, the method MT will be described using an example in which the method MT is performed using a plasma processing apparatus 1. In each step of the method MT, each part of the plasma processing apparatus 1 can be controlled by a control unit 2. Note that the method MT may also be performed using a plasma processing apparatus other than the plasma processing apparatus 1.

[0090] The method MT is performed while the substrate W is placed on the substrate support 11 in order to perform a plasma treatment on the substrate W. The plasma treatment may be, for example, etching of a film on the substrate W. The substrate W may have a mask on the film. The mask has a pattern to be transferred to the film on the substrate W by etching. Alternatively, the substrate W may not have a mask.

[0091] 1 , the method MT includes steps STa, STb, and STc. In step STa, plasma is generated in the chamber 10. In step STa, a gas is supplied from the gas supply unit 20 into the chamber 10. In step STa, the pressure in the chamber 10 is set to a specified pressure by the exhaust system 40. In step STa, plasma is generated from the gas in the chamber 10 by the plasma generation unit 12. Specifically, source radio frequency power RF is supplied from the radio frequency power supply 31 to the radio frequency electrode. As described above, the source radio frequency power RF may be supplied continuously, or pulses of the source radio frequency power RF may be supplied intermittently or periodically.

[0092] Step STb is performed to attract ions from the plasma generated in step STa to the substrate W. Step STb includes steps STb1 and STb2. In step STb1, the duration of a voltage pulse PV is set. In step STb2, a voltage pulse PV having the set duration is applied to the bias electrode by the bias power supply 32.

[0093] After step STb, it is determined in step STJ whether a stop condition is satisfied. The stop condition is satisfied if it is reached when the plasma processing is terminated. If the stop condition is not satisfied, step STb is repeated. That is, step STb is repeated in step STc. In step STc, the duration of the voltage pulse PV is changed to change the potential of the substrate W. On the other hand, if it is determined that the stop condition is not satisfied in step STJ, the method MT ends.

[0094] In one embodiment, the period during which process STc is performed may include multiple ON periods PP and multiple OFF periods. The multiple OFF periods alternate with the multiple ON periods PP. During each of the multiple ON periods PP, a voltage pulse PV is repeatedly applied to the bias electrode from the bias power supply 32. During each of the multiple OFF periods, application of the voltage pulse PV from the bias power supply 32 to the bias electrode is stopped.

[0095] In one embodiment, as described above with reference to (b) of Figure 5, in the repeated application of the voltage pulse PV to the bias electrode in each of the plurality of ON periods PP, the duration of the voltage pulse PV may be changed so as to change the potential of the substrate W. In one embodiment, as described above with reference to (b) of Figure 5, in the repeated application of the voltage pulse PV to the bias electrode in each of the plurality of ON periods PP, the duration of the voltage pulse PV may be increased. In one embodiment, in the repeated application of the voltage pulse PV to the bias electrode in each of the plurality of ON periods PP, the duration of the voltage pulse PV may be adjusted so as to bring the variation in the emission intensity or the emission intensity distribution in the chamber 10 closer to a predetermined value.

[0096] In one embodiment, as described above with reference to FIG. 6B , the duration of the voltage pulse PV in at least one ON period PP among the plurality of ON periods PP may be set to a value different from the duration of the voltage pulse PV in another ON period PP. As described above, for example, the duration of the voltage pulse PV in the ON period PP may be changed as etching of the film on the substrate W progresses. Note that the duration of the voltage pulse PV may be constant in each of the plurality of ON periods PP. Alternatively, the duration of the voltage pulse PV in each of the plurality of ON periods PP may be changed until it reaches its final value. For example, the duration of the voltage pulse PV in each of the plurality of ON periods PP may be increased until it reaches its final value. Alternatively, the duration of the voltage pulse PV in each of the plurality of ON periods PP may be adjusted until it reaches its final value so as to reduce the variation in the emission intensity or emission intensity distribution in the chamber 10 to a predetermined value.

[0097] In one embodiment, in addition to changing the duration of the voltage pulse PV, the set voltage level VB of the voltage pulse PV may be changed, as described above with reference to Figure 7. For example, the set voltage level VB may be changed for each of two or more ON periods PP that appear in sequence.

[0098] In one embodiment, the method MT may further include a step STd. The step STd includes adjusting a source frequency to reduce a degree of reflection of the source radio frequency power RF in at least each of a plurality of overlapping periods OP. In one embodiment, the source frequency may be adjusted to reduce a degree of reflection of the source radio frequency power RF in each of a plurality of phase periods SP within a waveform period CY of the electrical bias energy BE. For further specific examples of adjusting the source frequency, see the description of the first feedback and / or the second feedback above.

[0099] Reference will now be made to FIG. 8 . FIG. 8 is a diagram showing another example configuration of a power supply system in a plasma processing apparatus according to an exemplary embodiment. As shown in FIG. 8 , in another embodiment, the bias power supply 32 may include a DC power supply 32d and a switching unit 32s. The DC power supply 32d may be a variable DC power supply. The switching unit 32s generates a voltage pulse PV from the DC voltage output from the DC power supply 32d by switching between open and closed states.

[0100] 8, the plasma processing apparatus 1 may further include a damping circuit 34. The damping circuit 34 reduces the rate of change in the voltage level of the voltage pulse PV output from the bias power supply 32. The damping circuit 34 may include an inductor connected between the bias power supply 32 and the bias electrode, and a capacitor connected between one end of the inductor and ground. The damping circuit 34 may further include a resistive element connected in series with the inductor.

[0101] Reference will now be made to FIG. 9 . FIG. 9 is a partially enlarged cross-sectional view of another example of the substrate support. As shown in FIG. 9 , in another embodiment, the substrate support 11 may further include electrostatic electrodes 113a and 113b in addition to the electrostatic electrode 1111b. The electrostatic electrode 1111b is provided within the ceramic member 1111a in the central region 111a. The electrostatic electrode 1111b may have a substantially circular planar shape. A DC power supply 51p is connected to the electrostatic electrode 1111b via a switch 51s. When a voltage from the DC power supply 51p is applied to the electrostatic electrode 1111b, an electrostatic attractive force is generated between the substrate W and the central region 111a. Due to the generated electrostatic attractive force, the substrate W is attracted to the central region 111a and held by the central region 111a.

[0102] The electrostatic electrodes 113a and 113b are provided within the ceramic member 1111a in the annular region 111b. Each of the electrostatic electrodes 113a and 113b may be a single electrode having a substantially ring shape or may include multiple electrodes arranged along the circumferential direction. The electrostatic electrode 113a is provided inside the electrostatic electrode 113b. A DC power supply 52p is connected to the electrostatic electrode 113a via a switch 52s. A DC power supply 53p is connected to the electrostatic electrode 113b via a switch 53s. The DC power supplies 52p and 53p apply voltages to the electrostatic electrodes 113a and 113b so as to generate a potential difference between the electrostatic electrodes 113a and 113b. This generates an electrostatic attractive force between the annular region 111b and the edge ring. The generated electrostatic attractive force attracts the edge ring to the annular region 111b and holds it thereon. Note that a voltage may be applied to the electrostatic electrode 113a and the electrostatic electrode 113b from a single power source as long as a potential difference occurs between them.

[0103] 9, the substrate support 11 may further include a bias electrode 114a and a bias electrode 114b. The bias electrode 114a is provided in the ceramic member 1111a in the central region 111a. The bias electrode 114a may have a substantially circular planar shape. The bias electrode 114a may be provided between the electrostatic electrode 1111b and the base 1110.

[0104] The bias electrode 114b is provided in the ceramic member 1111a in the annular region 111b. The bias electrode 114b may be a single electrode having a substantially annular shape or may include a plurality of electrodes arranged along the circumferential direction. The bias electrode 114b may be provided between each of the electrostatic electrodes 113a and 113b and the base 1110.

[0105] 9, two bias power supplies 32A and 32B are employed instead of the single bias power supply 32. The bias power supplies 32A and 32B may have the same configuration as the bias power supply 32. The bias power supply 32A is electrically connected to the bias electrode 114a, and the bias power supply 32B is electrically connected to the bias electrode 114b. The bias power supplies 32A and 32B repeatedly apply voltage pulses PV synchronized with each other to the bias electrodes 114a and 114b, respectively.

[0106] Note that a voltage pulse PV from a single bias power supply may be repeatedly applied to both the bias power supply 32A and the bias power supply 32B. Also, the electrostatic electrode 1111b may be used as the bias electrode 114a, and the electrostatic electrodes 113a and 113b may be used as the bias electrode 114b.

[0107] 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.

[0108] 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, source radio frequency power RF is used to generate the plasma, and the source frequency of the source radio frequency power RF is adjusted as described above with respect to the plasma processing apparatus 1.

[0109] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E11] below.

[0110] [E1] A plasma processing method comprising: (a) generating a plasma in a chamber of a plasma processing apparatus, the plasma processing apparatus having a substrate support provided in the chamber, the substrate support supporting a substrate placed thereon; (b) applying a voltage pulse from a bias power supply to a bias electrode of the substrate support to attract ions from the plasma to the substrate; and (c) repeating (b), wherein in (c), the duration of the voltage pulse is changed to change the potential of the substrate.

[0111] [E2] The plasma processing method according to E1, wherein the period during which (c) is performed includes a plurality of ON periods and a plurality of OFF periods alternating with the plurality of ON periods, wherein in each of the plurality of ON periods, the voltage pulse is repeatedly applied from the bias power supply to the bias electrode, and the duration of the voltage pulse is changed to change the potential of the substrate, and wherein in each of the plurality of OFF periods, the application of the voltage pulse from the bias power supply to the bias electrode is stopped.

[0112] [E3] The plasma processing method according to E2, wherein the duration of the voltage pulse is increased in the repetition of application of the voltage pulse to the bias electrode in each of the plurality of ON periods.

[0113] [E4] The plasma processing method according to E2 or E3, wherein, in each of the plurality of ON periods, the duration length of the voltage pulse is adjusted so as to bring the variation in the emission intensity or the distribution of the emission intensity within the chamber closer to a predetermined value.

[0114] [E5] The plasma processing method according to any one of E1 to E4, wherein the period during which (c) is performed includes a plurality of ON periods and a plurality of OFF periods alternating with the plurality of ON periods, wherein the voltage pulse is repeatedly applied from the bias power supply to the bias electrode in each of the plurality of ON periods, and wherein the application of the voltage pulse from the bias power supply to the bias electrode is stopped in each of the plurality of OFF periods, and wherein the duration of the voltage pulse in at least one ON period of the plurality of ON periods is set to a value different from the duration of the voltage pulse in another ON period of the plurality of ON periods.

[0115] [E6] The plasma processing method according to any one of E1 to E5, wherein in (c), the electrical bias energy including the voltage pulse and having a waveform period is periodically applied to the bias electrode, and the duration of the voltage pulse is changed by changing a duty ratio of the voltage pulse in the waveform period.

[0116] [E7] The plasma processing method according to any one of E1 to E6, further comprising the step of adjusting a source frequency of source high frequency power supplied to generate the plasma so as to reduce a degree of reflection of the source high frequency power.

[0117] [E8] The plasma processing method of E7, wherein the source frequency is adjusted during each of a plurality of phase periods within a waveform period of the electrical bias energy comprising the voltage pulse.

[0118] [E9] The plasma processing method according to any one of E1 to E8, wherein (a), (b), and (c) are performed to etch a film on the substrate.

[0119] [E10] The plasma processing method according to any one of E1 to E9, wherein in (c), a set voltage level of the voltage pulse in the bias power supply is further changed.

[0120] [E11] A plasma processing apparatus comprising: a chamber; a substrate support provided within the chamber; a plasma generation unit configured to generate plasma within the chamber; and a bias power supply configured to repeatedly apply voltage pulses to a bias electrode of the substrate support to attract ions from the plasma to a substrate on the substrate support, wherein the bias power supply is configured to change the duration of the voltage pulses to change the potential of the substrate upon repeated application of the voltage pulses to the bias electrode.

[0121] 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.

[0122] 1... plasma processing apparatus, 10... chamber, 11... substrate support part, 12... plasma generating part, 31... high frequency power supply, 32... bias power supply

Claims

1. (a) A step of generating plasma in a chamber of a plasma processing apparatus, wherein the plasma processing apparatus has a substrate support portion provided in the chamber, and the substrate support portion supports a substrate placed thereon, and the step of generating plasma in a chamber of a plasma processing apparatus, (b) A step of applying a voltage pulse from a bias power supply to the bias electrode of the substrate support in order to draw ions from the plasma to the substrate, (c) A step of repeating (b) above, Includes, A plasma processing method in which, in (c) above, the duration of the voltage pulse is changed so as to change the potential of the substrate to a level below the maximum attainable potential of the substrate corresponding to the set voltage level of the voltage pulse.

2. The period during which (c) is performed includes multiple ON periods and multiple OFF periods alternating with the multiple ON periods. During each of the plurality of ON periods, the voltage pulse is repeatedly applied from the bias power supply to the bias electrode, and the duration of the voltage pulse is changed to change the potential of the substrate. During each of the plurality of OFF periods, the application of the voltage pulse from the bias power supply to the bias electrode is stopped. The plasma treatment method according to claim 1.

3. The plasma processing method according to claim 2, wherein the duration of the voltage pulse is increased during repeated application of the voltage pulse to the bias electrode in each of the plurality of ON periods.

4. The plasma processing method according to claim 2, wherein in each of the plurality of ON periods, the duration of the voltage pulse is adjusted so that the variation in the light emission intensity or distribution of light emission intensity within the chamber approaches a predetermined value.

5. The period during which (c) is performed includes multiple ON periods and multiple OFF periods alternating with the multiple ON periods. During each of the plurality of ON periods, the voltage pulse is repeatedly applied from the bias power supply to the bias electrode. During each of the aforementioned multiple OFF periods, the application of the voltage pulse from the bias power supply to the bias electrode is stopped. The duration of the voltage pulse in at least one of the plurality of ON periods is set to a value different from the duration of the voltage pulse in another ON period among the plurality of ON periods. A plasma treatment method according to any one of claims 1 to 4.

6. The plasma processing method according to any one of claims 1 to 4, wherein in (c) above, the electrical bias energy including the voltage pulse and having a waveform period is periodically applied to the bias electrode, and the duration of the voltage pulse is changed by changing the duty cycle of the voltage pulse in the waveform period.

7. A plasma processing method according to any one of claims 1 to 4, further comprising the step of adjusting the source frequency of the source high-frequency power supplied to generate the plasma so as to reduce the degree of reflection of the source high-frequency power.

8. The plasma processing method according to claim 7, wherein the source frequency is adjusted in each of a plurality of phase periods within the waveform period of the electrical bias energy including the voltage pulse.

9. The plasma treatment method according to any one of claims 1 to 4, wherein (a), (b), and (c) are performed to etch the film on the substrate.

10. The plasma processing method according to any one of claims 1 to 4, wherein in (c) above, the set voltage level of the voltage pulse in the bias power supply is further changed.

11. Chamber and, A substrate support portion provided within the chamber, A plasma generation unit configured to generate plasma within the chamber, A bias power supply configured to repeatedly apply voltage pulses to the bias electrode of the substrate support in order to draw ions from the plasma to the substrate on the substrate support, Equipped with, A plasma processing apparatus wherein the bias power supply is configured to change the duration of the voltage pulse in order to change the potential of the substrate to below the maximum attainable potential of the substrate corresponding to the set voltage level of the voltage pulse during repeated application of the voltage pulse to the bias electrode.

12. The bias power supply is In each of the multiple ON periods and the multiple OFF periods alternating between the multiple ON periods, the voltage pulse is repeatedly applied to the bias electrode, and the duration of the voltage pulse is changed to change the potential of the substrate. During each of the aforementioned multiple OFF periods, the application of the voltage pulse to the bias electrode is stopped. The plasma processing apparatus according to claim 11, configured as described above.

13. The plasma processing apparatus according to claim 12, wherein the bias power supply is configured to increase the duration of the voltage pulse during repeated application of the voltage pulse to the bias electrode in each of the plurality of ON periods.

14. The plasma processing apparatus according to claim 12, wherein the bias power supply is configured to adjust the duration of the voltage pulse so that the variation in the light emission intensity or distribution of light emission intensity in the chamber approaches a predetermined value during each of the plurality of ON periods.

15. The bias power supply is In each of the multiple ON periods and the multiple OFF periods alternating between the multiple ON periods, the voltage pulse is repeatedly applied to the bias electrode. During each of the aforementioned multiple OFF periods, the application of the voltage pulse to the bias electrode is stopped. The duration of the voltage pulse in at least one of the plurality of ON periods is set to a value different from the duration of the voltage pulse in another ON period among the plurality of ON periods. A plasma processing apparatus according to any one of claims 11 to 14, configured as described above.

16. The plasma processing apparatus according to any one of claims 11 to 14, wherein the bias power supply is configured to periodically apply the electrical bias energy, which includes the voltage pulse and has a waveform period, to the bias electrode, and to change the duration of the voltage pulse by changing the duty cycle of the voltage pulse in the waveform period.

17. The plasma generation unit includes a high-frequency power supply, The plasma processing apparatus according to any one of claims 11 to 14, wherein the high-frequency power supply is configured to adjust the source frequency of the source high-frequency power to reduce the degree of reflection of the source high-frequency power for generating the plasma.

18. The plasma apparatus according to claim 17, wherein the high-frequency power supply is configured to adjust the source frequency in each of a plurality of phase periods within the waveform period of the electrical bias energy including the voltage pulse.

19. The plasma processing apparatus according to any one of claims 11 to 14, wherein the bias power supply is configured to repeatedly apply the voltage pulse to the bias electrode to draw ions from the plasma generated by the plasma generation unit to the substrate, thereby etching the film on the substrate.

20. The plasma processing apparatus according to any one of claims 11 to 14, wherein the bias power supply is configured to further change the set voltage level of the voltage pulse during repeated application of the voltage pulse to the bias electrode.