Plasma treatment device, power supply system, and plasma treatment method

Abstract

This plasma treatment device comprises a chamber, a substrate support part in the chamber, a high-frequency power supply, a bias power supply, and a control unit. The high-frequency power supply is configured to supply source high-frequency power for generating plasma from a gas inside the chamber. The bias power supply is configured to supply an electric bias to the substrate support part for drawing ions from the plasma to a substrate on the substrate support part. The control unit is configured to control the high-frequency power supply and the bias power supply such that, in a plasma treatment period, the source high-frequency power and the electric bias are continuously and simultaneously supplied, and such that the power level of the source high-frequency power is set to not more than 3 kW, the bias frequency is set to less than 400 kHz, and the voltage amplitude of the electric bias is set to not less than 3 kV.

Description

Plasma processing apparatus, power supply system, and plasma processing method

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

[0002] A plasma processing apparatus is used in plasma processing of a substrate. The plasma processing apparatus described in Patent Document 1 includes a chamber and a substrate holding electrode. The substrate holding electrode is provided within the chamber. The substrate holding electrode holds a substrate placed on its main surface. The plasma processing apparatus described in Patent Document 1 also includes a radio-frequency generator and a DC negative pulse generator. The radio-frequency generator applies a radio-frequency voltage to the substrate holding electrode. The radio-frequency voltage is alternately switched on and off. The DC negative pulse generator applies a DC negative pulse voltage to the substrate holding electrode in accordance with the timing of the radio-frequency voltage being turned on and off.

[0003] JP 2009-187975 A

[0004] The present disclosure provides a technique for suppressing a decrease in etch rate.

[0005] In one exemplary embodiment, a plasma processing apparatus is disclosed. The plasma processing apparatus includes a chamber, a substrate support within the chamber, a radio frequency power source, a bias power source, and a controller. The radio frequency power source is configured to supply a source radio frequency power to generate plasma from a gas within the chamber. The bias power source is configured to supply an electric bias to the substrate support to attract ions from the plasma to a substrate on the substrate support. The controller is configured to control the radio frequency power source and the bias power source to continuously and simultaneously supply the source radio frequency power and the electric bias during a plasma processing period, and to set the power level of the source radio frequency power to 3 kW or less, the bias frequency, which is the reciprocal of the time length of the waveform period of the electric bias, to less than 400 kHz, and the voltage amplitude of the electric bias to 3 kV or more.

[0006] According to one exemplary embodiment, a technique is provided for reducing the decrease in etch rate.

[0007] 5A is a diagram for explaining an example of the configuration of a plasma processing system; FIG. 5B is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus; FIG. 5C is a diagram showing a plasma processing apparatus according to an exemplary embodiment; FIG. 5D is a diagram showing an example of an electric bias waveform; FIG. 5A is a timing chart of an example of a source high frequency power, and FIG. 5D is a timing chart of an example of an electric bias; FIG. 5E is a diagram showing an example of a plasma and a sheath in a chamber; FIG. 5F is a diagram showing a plasma processing method according to an exemplary embodiment; FIG. 5G is a diagram showing the results of a first experiment; FIG. 5H is a diagram showing the results of a second experiment; FIG. 5I is a diagram showing a plasma processing apparatus according to another exemplary embodiment; FIG. 5I is a block diagram of a processing circuit for performing the operations described herein on a computer.

[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). Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[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 20, a power supply 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 showerhead 13 and the substrate support 11 are 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 conductive member of the base 1110 can function as a lower electrode. 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. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Furthermore, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[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 power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This generates a plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0021] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0022] The second RF generator 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0023] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to the at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to the at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0024] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0025] 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.

[0026] Reference will now be made to FIG. 3 . FIG. 3 is a diagram illustrating a plasma processing apparatus according to an exemplary embodiment. As illustrated in FIG. 3 , the plasma processing apparatus 1 includes a high-frequency power supply 41 and a bias power supply 42. The high-frequency power supply 41 and the bias power supply 42 constitute a power supply system 30S. The power supply system 30S may further include a control unit 2. Alternatively, the power supply system 30S may include a control unit other than the control unit 2 that can perform the same control of the high-frequency power supply 41 and the bias power supply 42 as that performed by the control unit 2 described below. Alternatively, the power supply system 30S may not include a control unit, and the high-frequency power supply 41 and the bias power supply 42 may be configured to perform the respective operations described below.

[0027] The high frequency power supply 41 is the first RF generating unit 31a. The high frequency power supply 41 is configured to generate a source RF signal, i.e., a source high frequency power HF. The source high frequency power HF has a source frequency. That is, the source high frequency power HF has a sinusoidal waveform whose frequency is the source frequency. The source frequency may be a frequency within a range of 10 MHz to 150 MHz.

[0028] The high frequency power supply 41 is electrically connected to the high frequency electrode via a matching box 43 and is configured to supply source high frequency power HF to the high frequency electrode. The high frequency electrode may be provided within the substrate support 11. The high frequency electrode may be at least one electrode provided within the conductive member or ceramic member 1111a of the base 1110. Alternatively, the high frequency electrode may be an upper electrode. When the source high frequency power HF is supplied to the high frequency electrode, plasma is generated from the gas within the chamber 10.

[0029] The matching circuit 43 has a variable impedance. The variable impedance of the matching circuit 43 is set to reduce reflection of the source high frequency power HF from the load. The matching circuit 43 can be controlled by, for example, the control unit 2.

[0030] The bias power supply 42 includes the second RF generator 31b or the first DC generator 32a. The bias power supply 42 is electrically coupled to the substrate support 11. The bias power supply 42 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 1111a 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.

[0031] 4 will be referred to in conjunction with FIG. 3. FIG. 4 is a diagram showing an example of the waveform of the electrical bias. The bias power supply 42 generates a waveform having a period C Ｗ The bias electrode is configured to periodically apply an electric bias EB having a waveform period C Ｗ A plurality of waveform periods C Ｗ is applied to the bias electrode at each of the waveform periods C Ｗ is defined by the bias frequency. The bias frequency is, for example, 50 kHz or more and 27 MHz or less. The electric bias EB has a bias frequency. The waveform period C Ｗ The time length of is the reciprocal of the bias frequency. The bias frequency may be 13.56 MHz or less or 400 kHz or less.

[0032] The electrical bias EB may be a bias RF signal, i.e., a bias high frequency power LF having a bias frequency. That is, the electrical bias EB may have a sinusoidal waveform whose frequency is the bias frequency. In this case, the bias power supply 42 is electrically connected to the bias electrode via a matching box 44. The variable impedance of the matching box 44 is set to reduce reflection of the bias high frequency power LF from the load.

[0033] Alternatively, the electrical bias EB may include a pulsed first DC signal, i.e., a voltage pulse VP. The voltage pulse VP has a waveform period C Ｗ The voltage pulse VP is applied to the bias electrode within a waveform period CＷ The voltage pulse VP is periodically applied to the bias electrode at a time interval equal to the time length of the voltage pulse VP. The waveform of the voltage pulse VP may be a square wave, a triangular wave, or any other waveform. The polarity of the voltage of the voltage pulse VP is set so as to generate a potential difference between the substrate W and the plasma, thereby attracting ions from the plasma to the substrate W. The voltage pulse VP has a waveform period C during which the potential of the substrate W is negative. Ｗ is applied to the bias electrode so as to include the voltage pulse VP. The voltage pulse VP applied to the bias electrode may have a negative potential, a positive potential, or a potential that changes between a positive potential and a negative potential. The voltage pulse VP may be a negative voltage pulse or a negative DC voltage pulse. Note that when the electric bias EB is a voltage pulse VP, the plasma processing apparatus 1 does not need to be equipped with the matching unit 44.

[0034] Hereinafter, reference will be made to Figures 5(a) and 5(b) together with Figure 3. Figure 5(a) is a timing chart of an example of source high frequency power, and Figure 5(b) is a timing chart of an example of electric bias. In Figure 5(a), ON of source high frequency power HF indicates that source high frequency power HF is being supplied, and OFF of source high frequency power HF indicates that source high frequency power HF is being stopped. In Figure 5(b), ON of electric bias EB indicates that electric bias EB is being supplied, and OFF of electric bias EB indicates that electric bias EB is being stopped.

[0035] As shown in FIG. 5A, the control unit 2 controls the plasma processing period P Ｓ In the plasma processing period P, the high frequency power supply 41 and the bias power supply 42 are controlled so as to supply the source high frequency power HF and the electric bias EB continuously and simultaneously. In the example shown in FIG. 5A, the source high frequency power HF and the electric bias EB may be supplied continuously for 1 minute or more, 5 minutes or more, or 10 minutes or more. Ｓ In the process, a substrate W on a substrate support 11 can be treated using a plasma generated in the chamber 10 .

[0036] The control unit 2 controls the plasma processing period PＳ In this case, the radio frequency power supply 41 and the bias power supply 42 are controlled so that the power level of the source radio frequency power HF is set to 3 kW or less, the bias frequency is set to less than 400 kHz, and the voltage amplitude of the electric bias EB is set to 3 kV or more. The voltage amplitude of the electric bias EB can be the voltage amplitude of the electric bias EB at the output of the bias power supply 42, the bias electrode, or the substrate W. When the electric bias EB includes a voltage pulse VP, the voltage amplitude of the electric bias EB is the amplitude of the voltage pulse VP. When the electric bias EB includes a voltage pulse VP, the voltage amplitude of the electric bias EB can be the absolute value of the voltage level of the voltage pulse VP with respect to a reference potential. The reference potential of the voltage pulse VP is set to a value within a waveform period C. Ｗ The voltage level of the electric bias EB during the period when the voltage pulse VP is not generated within the period is, for example, 0 V. When the electric bias EB is the bias high frequency power LF, the voltage amplitude of the electric bias EB is the peak-to-peak voltage (V ＰＰ )

[0037] In the plasma processing apparatus 1, the plasma processing period P Ｓ In this case, the source high frequency power HF having a relatively low power level is used. Therefore, according to the plasma processing apparatus 1, the high frequency power supply 41 can be made smaller and consume less power.

[0038] Furthermore, the plasma processing apparatus 1 uses an electric bias EB having a bias frequency of less than 400 kHz. The electric bias EB having a bias frequency of less than 400 kHz suppresses reflection of the source high frequency power HF from the load of the high frequency power supply 41 and promotes coupling of the source high frequency power HF to the plasma.

[0039] 6 will be referred to below. FIG. 6 is a diagram showing an example of the plasma and sheath in the chamber. In FIG. 6, the plasma PL when the electric bias EB has a negative peak voltage is shown by a solid line, and the plasma PL when the electric bias EB has a positive peak voltage is shown by a dashed line. Note that when the electric bias EB includes a voltage pulse VP, the negative peak voltage is ＷWhen the electric bias EB includes the voltage pulse VP, the positive peak voltage is the voltage of the voltage pulse VP during the period in which the voltage pulse VP is output within the waveform period C. Ｗ When the electric bias EB is the bias high frequency power LF, the negative peak voltage is Ｗ In addition, when the electric bias EB is the bias high frequency power LF, the positive peak voltage is Ｗ is the positive peak voltage of the bias high frequency power LF in the

[0040] As shown in Figure 6, when the electric bias EB has a relatively positive peak voltage, the thickness of the sheath SB (plasma sheath) between the plasma PL and the substrate W is small, and the sheath voltage is also small. On the other hand, when the electric bias EB has a negative peak voltage, the thickness of the sheath SA (plasma sheath) between the plasma PL and the substrate W is large, and the sheath voltage is also large. When the voltage of the electric bias EB switches from a positive peak voltage to a negative peak voltage, that is, when the sheath voltage (potential difference) between the plasma PL and the substrate W switches from minimum to maximum, many of the ions in the plasma PL that were present in the region VR of the sheath SA excluding the sheath SB region are accelerated by the relatively large sheath voltage and drawn into the substrate W. In the plasma processing apparatus 1, as described above, the plasma processing period P Ｓ Since the voltage amplitude of the electric bias EB is set to 3 kV or more during the plasma processing period P Ｓ The thickness of the region VR in the plasma processing apparatus 1 can be increased. Therefore, with the plasma processing apparatus 1, even if the density of the plasma PL is low, a large number of ions having high energy can be attracted to the substrate W. Therefore, with the plasma processing apparatus 1, it is possible to suppress a decrease in the etch rate. Furthermore, with the plasma processing apparatus 1, a source high frequency power of a low power level may be used, and even if a source high frequency power of a low power level is used, it is possible to suppress a decrease in the etch rate.

[0041] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ One or more control parameters of the plasma processing apparatus 1 may be changed over time. The one or more control parameters may include the voltage amplitude, bias frequency, waveform period C of the electric bias EB, and the like. Ｗ The control parameter includes at least one selected from the group consisting of the duty ratio (ON duty) of the voltage pulse VP in the chamber 10, the pressure in the chamber 10, the power level of the source high frequency power HF, the frequency of the source high frequency power HF, and the temperature of the substrate support 11.

[0042] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ The bias power supply 42 may be controlled so as to increase the voltage amplitude of the electric bias EB as time passes during the plasma processing period P Ｓ As a result, it becomes possible to supply ions to the bottom of a high aspect ratio recess of the substrate W.

[0043] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ The bias power supply 42 may be controlled to change the bias frequency as time passes during the plasma processing period P Ｓ When the bias frequency is decreased as time passes in the plasma processing period P Ｓ As a result, the charge on the substrate W is alleviated or eliminated, and the supply of ions to the bottom of the high aspect ratio recess of the substrate W is promoted. Ｓ When the bias frequency is increased over time in the etching process, charging of the substrate W suppresses the supply of low-energy ions to the bottom of the recessed portion of the substrate W. Furthermore, the number of times ions are incident increases, resulting in a higher etching rate.

[0044] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ As time passes, the waveform period C ＷIn this case, the time during which electrons are supplied to the bottom of the recess of the substrate W is equal to the plasma processing period P Ｓ As a result, the charge on the substrate W is alleviated or eliminated, and the supply of ions to the bottom of the high aspect ratio recess of the substrate W is promoted.

[0045] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ The exhaust system 40 may be controlled to reduce the pressure in the chamber 10 over time during the plasma processing period P. In this case, the mean free path of activated species such as ions and / or radicals is Ｓ As the time passes, the supply of activated species to the bottom of the high aspect ratio recess of the substrate W is promoted.

[0046] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ The high frequency power supply 41 may be controlled to change the power level of the source high frequency power HF over time in the process. The power level of the source high frequency power HF may be increased or decreased depending on the balance of ions and radicals at the bottom of the recess of the substrate W.

[0047] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ The high frequency power supply 41 may be controlled to change the frequency of the source high frequency power HF depending on the passage of time in the load of the high frequency power supply 41. The frequency of the source high frequency power HF may be changed to suppress reflection of the source high frequency power HF from the load of the high frequency power supply 41.

[0048] In one embodiment, the control unit 2 controls the plasma processing period P Ｓ The temperature adjustment mechanism may be controlled so as to decrease the temperature of the substrate support 11 as time passes during the plasma processing period P. The temperature adjustment mechanism may be the temperature adjustment module described above. The temperature adjustment mechanism controls, for example, the temperature of the heat transfer fluid supplied to the flow path 1110a. In this case, the adsorption coefficient of radicals on the surface defining the bottom of the recess of the substrate W is Ｓ It increases with time in

[0049] In the above embodiment, the controller 2 changes one or more control parameters of the plasma processing apparatus 1 as time passes during the plasma processing period PS. Alternatively, the controller 2 may change one or more control parameters of the plasma processing apparatus 1 as the depth or aspect ratio of a recess formed in the substrate W by etching increases. Alternatively, the controller 2 may change one or more control parameters of the plasma processing apparatus 1 in response to the amount of etching by-products measured by a sensor. The sensor may be, for example, an optical analyzer or a quadrupole mass spectrometer that analyzes the light emission or optical absorption of the by-products. Alternatively, the controller 2 may change one or more control parameters of the plasma processing apparatus 1 in response to a calculation result from one or more of the elapsed time during the plasma processing period PS, the depth of the recess, the aspect ratio of the recess, and the amount of etching by-products measured by the sensor.

[0050] A plasma processing method according to one exemplary embodiment will be described below with reference to FIG. 7 . FIG. 7 is a diagram illustrating a plasma processing method according to one exemplary embodiment. In the plasma processing method shown in FIG. 7 (hereinafter referred to as "method MT"), each part of a plasma processing apparatus 1 can be controlled by a controller 2. Method MT includes steps STa and STb. Method MT may further include step STp.

[0051] In the process STp, a substrate W is prepared in the chamber 10. The substrate W is placed on the substrate support 11. The processes STa and STb can be performed in a state in which the substrate W is placed on the substrate support 11.

[0052] In the process STa, the plasma processing period P Ｓ In order to generate plasma from the gas in the chamber 10, a source high frequency power HF is supplied from the high frequency power supply 41 to the high frequency electrode. The process STb is performed simultaneously with the process STa. In the process STb, during the plasma processing period P Ｓ An electrical bias EB is supplied to the substrate support 11 simultaneously and continuously with the supply of the source radio frequency power HF to attract ions from the plasma to the substrate W at .

[0053] Plasma processing period P Ｓ In the plasma processing period P, the power level of the source high frequency power HF is set to 3 kW or less, the bias frequency of the electric bias EB is set to less than 400 kHz, and the voltage amplitude of the electric bias EB is set to 3 kV or more. Ｓ In this case, one or more control parameters may be changed, as described above.

[0054] In the method MT, a silicon-containing film on the substrate W may be etched. The silicon-containing film may be a single-layer film including at least one film selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polycrystalline silicon film, or a multilayer film including two or more films selected from the group. In this case, the gas used to generate plasma in the step STa may contain hydrogen fluoride gas. This gas may further contain a phosphorus-containing gas. This gas may further contain an oxygen-containing gas and / or a rare gas.

[0055] An experiment conducted to evaluate the plasma processing apparatus 1 will now be described.

[0056] (First Experiment)

[0057] In the first experiment, the thickness ΔT of the region VR was measured by observing the plasma emission in the chamber 10 with a camera while changing the power level of the source high frequency power HF. In the first experiment, a voltage pulse VP was used as the electric bias EB. The bias frequency of the electric bias EB, the amplitude of the voltage pulse VP, and the duty ratio of the voltage pulse VP were 400 kHz, −5 kV, and 20%, respectively. FIG. 8 shows the results of the first experiment. In FIG. 8, the horizontal axis represents the power level of the source high frequency power HF, and the vertical axis represents the thickness ΔT. As shown in FIG. 8, the first experiment confirmed that the thickness ΔT increased when the power level of the source high frequency power HF was 3 kW or less.

[0058] (Second Experiment)

[0059] In the second experiment, the thickness ΔT of the region VR was measured by observing the plasma emission in the chamber 10 with a camera while changing the amplitude of the voltage pulse VP of the electric bias EB. In the second experiment, the bias frequency of the electric bias EB, the duty ratio of the voltage pulse VP, and the power level of the source high frequency power HF were 400 kHz, 20%, and 1 kW, respectively. FIG. 9 shows the results of the second experiment. In FIG. 9, the horizontal axis represents the amplitude of the voltage pulse VP, and the vertical axis represents the thickness ΔT. As shown in FIG. 9, the second experiment confirmed that the thickness ΔT increased when the amplitude of the voltage pulse VP was greater than 2 kV. It was also confirmed that the thickness ΔT increased significantly when the amplitude of the voltage pulse VP was greater than 3 kV.

[0060] (Third Experiment)

[0061] In the third experiment, three types of voltage pulses VP having the same ON time length were used as the electric bias EB, and the plasma processing period P Ｓ The reflectivity of the source high frequency power HF was measured. The reflectivity is the ratio of the power level of the reflected wave of the source high frequency power HF to the power level of the traveling wave of the source high frequency power HF. The bias frequency and duty ratio of the first voltage pulse of the three voltage pulses VP were 400 kHz and 20%, respectively. The bias frequency and duty ratio of the second voltage pulse of the three voltage pulses VP were 200 kHz and 10%, respectively. The bias frequency and duty ratio of the third voltage pulse of the three voltage pulses VP were 100 kHz and 5%, respectively. In the third experiment, the power level of the source high frequency power HF was 0.6 kW. The results of the third experiment showed that the reflectivities when the first to third voltage pulses were used were 34.4%, 23.4%, and 15.6%, respectively. The third experiment confirmed that the reflectivity can be significantly reduced by using an electrical bias EB with a bias frequency of less than 400 kHz.

[0062] 10 is a diagram showing a plasma processing apparatus 1A according to another exemplary embodiment. The plasma processing apparatus 1A will be described below from the viewpoint of differences from the plasma processing apparatus 1.

[0063] As shown in FIG. 10, in a plasma processing apparatus 1 A, a high frequency power supply 41 is electrically connected to a base 1110 of a substrate support 11 via a matching box 43 .

[0064] The substrate support 11 includes a first region R1 and a second region R2. In FIG. 10 , the boundary between the first region R1 and the second region R2 is indicated by a dashed line. The first region R1 is a region that intersects with the axis AX and has a generally disk shape. The axis AX is the central axis of the substrate support 11 and may coincide with the central axis of the chamber 10. The first region R1 includes the above-mentioned substrate support surface 111a as its upper surface. The second region R2 extends to surround the first region R1. The substrate W is placed on the substrate support surface 111a and is supported on the first region R1. The second region R2 is an annular region around the axis AX. The second region R2 includes the above-mentioned ring support surface 111b as its upper surface. The edge ring ER included in the ring assembly 112 is placed on the ring support surface 111b and supported on the second region R2. The substrate W is placed within the region surrounded by the edge ring ER.

[0065] The substrate support 11 includes a first electrode BE1 and a second electrode BE2 as bias electrodes. The first electrode BE1 extends below the substrate support surface 111a and is disposed within the first region R1. The first electrode BE1 may be a film formed from a conductive material. The first electrode BE1 may have a substantially circular planar shape. The first electrode BE1 may be disposed so that its center is located on the axis AX.

[0066] The second electrode BE2 extends below the ring support surface 111b and within the second region R2. The second electrode BE2 may be a film made of a conductive material. The second electrode BE2 may have a substantially annular planar shape. The second electrode BE2 may be disposed such that its center is located on the axis AX.

[0067] 10 , the electrostatic chuck 1111 may include a dielectric portion 1111d. The dielectric portion 1111d may be the ceramic member 1111a described above. A central portion of the dielectric portion 1111d may form a first region R1 and may have the substrate support surface 111a as its upper surface. A peripheral portion of the dielectric portion 1111d may form a second region R2 and may have the ring support surface 111b as its upper surface.

[0068] The electrostatic chuck 1111 may include a chuck electrode CE1 as part of the electrostatic electrode 1111b. The chuck electrode CE1 is disposed within the dielectric portion 1111d and within the first region R1. The chuck electrode CE1 may be a film formed of a conductive material. The chuck electrode CE1 may have a substantially circular planar shape. The chuck electrode CE1 may be disposed such that its center is located on the axis AX. The chuck electrode CE1 may extend between the substrate support surface 111a and the first electrode BE1.

[0069] The electrostatic chuck 1111 may also include chuck electrodes CE2 and CE3 as separate parts of the electrostatic electrode 1111b. Each of the chuck electrodes CE2 and CE3 is disposed within the dielectric portion 1111d and the second region R2. Each of the chuck electrodes CE2 and CE3 may be a film formed of a conductive material. Each of the chuck electrodes CE2 and CE3 may extend circumferentially around the axis AX or have a substantially annular planar shape. The chuck electrode CE2 is disposed inward relative to the chuck electrode CE3. That is, the radial distance between the chuck electrode CE2 and the axis AX is smaller than the radial distance between the chuck electrode CE3 and the axis AX. Each of the chuck electrodes CE2 and CE3 may also extend between the ring support surface 111b and the second electrode BE2.

[0070] The plasma processing apparatus 1A may further include a DC power supply 51p. The DC power supply 51p is electrically connected to the chuck electrode CE1 via a switch 51s. A filter 51f may further be connected between the DC power supply 51p and the chuck electrode CE1. The filter 51f is a low-pass filter configured to block or attenuate RF signals such as source high-frequency power HF. When a voltage from the DC power supply 51p is applied to the chuck electrode CE1, an electrostatic attraction force is generated between the electrostatic chuck 1111 and the substrate W. The generated electrostatic attraction force attracts the substrate W to the first region R1 and holds it there.

[0071] The plasma processing apparatus 1A may further include DC power supplies 52p and 53p. The DC power supply 52p is electrically connected to the chuck electrode CE2 via a switch 52s. A filter 52f may be further connected between the DC power supply 52p and the chuck electrode CE2. The filter 52f is a low-pass filter configured to block or attenuate RF signals such as the source high frequency power HF. The DC power supply 53p is electrically connected to the chuck electrode CE3 via a switch 53s. A filter 53f may be further connected between the DC power supply 53p and the chuck electrode CE3. The filter 53f is a low-pass filter configured to block or attenuate RF signals such as the source high frequency power HF. When voltages from the DC power supplies 52p and 53p are applied to the chuck electrodes CE2 and CE3, an electrostatic attraction force is generated between the electrostatic chuck 1111 and the edge ring ER. The edge ring ER is attracted to the second region R2 by the generated electrostatic force and held by the second region R2. Note that a voltage may be applied to the chuck electrodes CE2 and CE3 so as to generate a potential difference therebetween. That is, the second region R2 may constitute a bipolar electrostatic chuck.

[0072] In the plasma processing apparatus 1A, the bias power supply 42 is configured to supply an electric bias EB to both the first electrode BE1 and the second electrode BE2. The bias power supply 42 may be a single power supply configured to distribute the electric bias EB to both the first electrode BE1 and the second electrode BE2. The bias power supply 42 may include a first power supply 421 electrically connected to the first electrode BE1 and a second power supply 422 electrically connected to the second electrode BE2. The first power supply 421 supplies the electric bias EB to the first electrode BE1, and the second power supply 422 supplies the electric bias EB to the second electrode BE2.

[0073] In the plasma processing apparatus 1A, the control unit 2 may control the bias power supply 42 to increase the level of the electric bias EB supplied to the second electrode BE2 relative to the level of the electric bias EB supplied to the first electrode BE1 as the wear rate of the edge ring ER increases. When the electric bias EB includes a voltage pulse VP, the level of the electric bias EB is the amplitude of the voltage pulse VP. When the electric bias EB is a bias high-frequency power LF, the level of the electric bias EB is the power level of the bias high-frequency power LF. According to the plasma processing apparatus 1A, by adjusting the level of the electric bias EB supplied to the second electrode BE2 relative to the level of the electric bias EB supplied to the first electrode BE1, it is possible to reduce the difference between the upper end position of the sheath above the substrate W and the upper end position of the sheath above the edge ring ER. As a result, it is possible to correct the traveling direction of ions relative to the edge of the substrate W to a perpendicular direction.

[0074] The thickness of the sheath is inversely proportional to the 1 / 2 power of the plasma density. Ｓ Since the source high frequency power HF is continuously supplied in the plasma generation chamber 10, fluctuations in plasma density are small. Therefore, by continuously supplying the electric bias EB, the level of which is individually adjusted, to the first electrode BE1 and the second electrode BE2, it is possible to reduce the difference between the upper end position of the sheath above the substrate W and the upper end position of the sheath above the edge ring ER.

[0075] The following describes examples of processing circuits that can be used as one or more processing circuits in the plasma processing apparatuses 1 and 1A, such as the controller 2 and / or the controller of the power supply system 30S. FIG. 11 is a block diagram of a processing circuit for implementing the operations described herein on a computer. FIG. 11 illustrates a processing circuit 130 that can be used to control a control process on any computer. The descriptions or blocks in the flowcharts represent modules, segments, or portions of code that include one or more executable instructions for implementing specific logical functions or steps of the process. As will be understood by those skilled in the art, other examples having functions that can be performed in a different order than that shown or described, such as substantially simultaneously or in reverse order, depending on the functionality involved, are within the scope of the exemplary embodiments of the present disclosure. The various elements, features, and processes described herein may be used independently of each other or combined in various ways. All conceivable combinations and subcombinations are within the scope of the present disclosure.

[0076] In Figure 11, processing circuitry 130 includes a CPU 1200 that performs one or more of the control processes described above and / or below. Process data and instructions may be stored in memory 1202. These process data and instructions may be stored on a storage medium disk 1204, such as a hard disk drive (HDD) or a portable storage medium, or may be stored remotely. Furthermore, the present disclosure as claimed is not limited by the form of computer-readable medium on which instructions for processes according to the present invention are stored. For example, these instructions may be stored on a CD, DVD, flash memory, RAM, ROM, PROM, EPROM, EEPROM, hard disk, or any other information processing device, such as a server and / or computer, with which processing circuitry 130 communicates.

[0077] Furthermore, the claimed disclosure may be provided as a utility application, a background daemon, a component of an operating system, or a combination thereof, and may execute in conjunction with CPU 1200 and an operating system known to those skilled in the art, such as Microsoft Windows®, UNIX®, Solaris®, LINUX®, Apple MAC-OS, etc.

[0078] The hardware elements that make up the processing circuit 130 can be realized by various circuit elements. Furthermore, each function of the above-described embodiments can be implemented by a circuit including one or more processing circuits. As shown in FIG. 11 , the processing circuit includes a specifically programmed processing unit, such as a processing unit (CPU) 1200. The processing circuit also includes devices such as application specific integrated circuits (ASICs) or conventional circuit components configured to perform the described functions.

[0079] 11, the processing circuit 130 includes a CPU 1200 that performs the above-described processing. The processing circuit 130 may be a general-purpose computer or a specific dedicated machine. In one embodiment, when the processing device 1200 is programmed to control the plasma generating unit 12 and the gas supply unit 20 and / or to control the high frequency power supply 41 and the bias power supply 42, the processing circuit 130 functions as a specific dedicated machine.

[0080] Alternatively or additionally, CPU 1200 may be implemented on an FPGA, ASIC, PLD, or using discrete logic circuitry, as will be appreciated by those skilled in the art. Furthermore, CPU 1200 may be implemented as multiple processing units cooperating to perform in parallel the instructions of the processes of the present invention described above.

[0081] The processing circuitry 130 of Figure 11 also includes a network controller 1206, such as an Intel Ethernet PRO network interface card from Intel Corporation of America, for interfacing with a network 1228. As can be appreciated, the network 1228 may be a public network such as the Internet, a private network such as a LAN or WAN, or any combination thereof, and may also include sub-networks such as PSTN or ISDN. The network 1228 may also be wired, such as an Ethernet network, or wireless, such as a cellular network including EDGE, 3G, and 4G wireless cellular systems. The wireless network may also be Wi-Fi, Bluetooth, or any other known form of wireless communication.

[0082] The processing circuitry 130 further includes a display device controller 1208, such as a graphics card or graphics adapter, for interfacing with a display device 1210, such as a monitor. A general-purpose I / O interface 1212 interfaces with a keyboard and / or mouse 1214 and a touch panel 1216, which may be integral with or separate from the display device 1210. The general-purpose I / O interface also connects to various peripheral devices 1218, such as printers and scanners.

[0083] The storage controller 1224 is connected to the storage media disk 1204 via a communication bus 1226, such as ISA, EISA, VESA, PCI, etc., and all components of the processing circuit 130 are connected to each other. The display device 1210, keyboard and / or mouse 1214, and the general features and functions of the display device controller 1208, storage controller 1224, network controller 1206, audio controller 1220, and general purpose I / O interface 1212 are not described herein for the sake of brevity, as they are well known.

[0084] The exemplary circuit elements described in this disclosure may be substituted with other elements and may have different structures than the examples described herein. Furthermore, circuits configured to implement the features described herein may be implemented in multiple circuit units (e.g., chips), or these features may be combined into the circuitry of a single chipset.

[0085] The functions and features described herein may also be performed by various distributed components on a system. For example, one or more processing devices may perform the functions of these systems, where the processing devices are distributed across multiple components communicating within a network. Distributed components may include various human interface and communication devices (e.g., display monitors, smartphones, tablets, personal digital assistants (PDAs)), as well as one or more client and server machines that can share processing. The network may be a private network, such as a LAN or WAN, or a public network, such as the Internet. Input to the system may be received directly by a user or remotely in real time or as a batch process. Furthermore, portions of the embodiments may be implemented on modules or hardware other than those described above. Accordingly, other embodiments are within the scope of the claims.

[0086] 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.

[0087] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E17] below.

[0088] [E1] A plasma processing apparatus comprising: a chamber; a substrate support within the chamber; a radio frequency power supply configured to supply source radio frequency power to generate plasma from gas within the chamber; a bias power supply configured to supply an electric bias to the substrate support to attract ions from the plasma to a substrate on the substrate support; and a controller configured to control the radio frequency power supply and the bias power supply, wherein the controller is configured to control the radio frequency power supply and the bias power supply so as to continuously and simultaneously supply the source radio frequency power and the electric bias during a plasma processing period, and to set a power level of the source radio frequency power to 3 kW or less, a bias frequency which is the reciprocal of the time length of a waveform cycle of the electric bias to less than 400 kHz, and a voltage amplitude of the electric bias to 3 kV or more.

[0089] [E2] The plasma processing apparatus according to E1, wherein the control unit is configured to control the bias power supply so as to increase the voltage amplitude as time passes during the plasma processing period.

[0090] [E3] The plasma processing apparatus according to E1 or E2, wherein the control unit is configured to control the bias power supply so as to change the bias frequency as time passes during the plasma processing period.

[0091] [E4] The plasma processing apparatus according to any one of E1 to E3, wherein the electrical bias is a voltage pulse that is periodically supplied at a time interval of the waveform period, and the voltage amplitude is the amplitude of the voltage pulse.

[0092] [E5] The plasma processing apparatus according to E4, wherein the control unit is configured to control the bias power supply so as to decrease a duty ratio of the voltage pulse in the waveform cycle as time passes during the plasma processing period.

[0093] [E6] The plasma processing apparatus according to any one of E1 to E3, wherein the electrical bias is a bias high frequency power having the bias frequency, and the voltage amplitude is a peak-to-peak voltage of the bias high frequency power.

[0094] [E7] The plasma processing apparatus according to any one of E1 to E6, further comprising an exhaust system configured to exhaust gas from the chamber, wherein the control unit is configured to control the exhaust system to reduce the pressure in the chamber as time passes during the plasma processing period.

[0095] [E8] The plasma processing apparatus according to any one of E1 to E7, wherein the control unit is configured to control the high frequency power supply so as to change the power level of the source high frequency power as time passes during the plasma processing period.

[0096] [E9] The plasma processing apparatus according to any one of E1 to E8, further comprising a temperature adjustment mechanism configured to adjust the temperature of the substrate support part, wherein the control unit is configured to control the temperature adjustment mechanism so as to decrease the temperature of the substrate support part as time passes during the plasma processing period.

[0097] [E10] A power supply system comprising: a radio frequency power supply configured to supply source radio frequency power to generate plasma from gas in a chamber of a plasma processing apparatus; and a bias power supply configured to supply an electric bias to a substrate support in the chamber to attract ions from the plasma to a substrate on the substrate support in the chamber, wherein the radio frequency power supply and the bias power supply are configured to continuously and simultaneously supply the source radio frequency power and the electric bias, respectively, during a plasma processing period, the radio frequency power supply is configured to set a power level of the source radio frequency power to 3 kW or less during the plasma processing period, and the bias power supply is configured to set a bias frequency, which is the reciprocal of the time length of a waveform cycle of the electric bias, to less than 400 kHz and a voltage amplitude of the electric bias to 3 kV or more during the plasma processing period.

[0098] [E11] The power supply system of E10, wherein the bias power supply is configured to increase the voltage amplitude over time during the plasma processing period.

[0099] [E12] The power supply system of E10 or E11, wherein the bias power supply is configured to change the bias frequency over time during the plasma processing period.

[0100] [E13] The power supply system according to any one of E10 to E12, wherein the electrical bias is a voltage pulse that is periodically supplied at a time interval of the waveform period, and the voltage amplitude is the amplitude of the voltage pulse.

[0101] [E14] The power supply system according to E13, wherein the bias power supply is configured to decrease a duty ratio of the voltage pulse in the waveform period as time passes during the plasma processing period.

[0102] [E15] The power supply system according to any one of E10 to E12, wherein the electrical bias is a bias high frequency power having the bias frequency, and the voltage amplitude is a peak-to-peak voltage of the bias high frequency power.

[0103] [E16] The power supply system according to any one of E10 to E15, wherein the high frequency power supply is configured to change a power level of the source high frequency power over time during the plasma processing period.

[0104] [E17] A plasma processing method comprising: (a) a step of continuously supplying source radio frequency power to generate plasma from a gas in a chamber of a plasma processing apparatus during a plasma processing period; and (b) a step of continuously supplying an electric bias to the substrate support part simultaneously with the supply of the source radio frequency power in (a) to attract ions from the plasma to a substrate on a substrate support part in the chamber during the plasma processing period, wherein during the plasma processing period, the power level of the source radio frequency power is set to 3 kW or less, a bias frequency which is the reciprocal of the time length of a waveform cycle of the electric bias is set to less than 400 kHz, and a voltage amplitude of the electric bias is set to 3 kV or more.

[0105] 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.

[0106] 1... plasma processing apparatus, 2... control section, 10... chamber, 11... substrate support section, 41... high frequency power supply, 42... bias power supply

Claims

1. A plasma processing apparatus comprising: a chamber; a substrate support within the chamber; a radio frequency power supply configured to supply source radio frequency power to generate plasma from gas within the chamber; a bias power supply configured to supply an electric bias to the substrate support to attract ions from the plasma to a substrate on the substrate support; and a control unit configured to control the radio frequency power supply and the bias power supply, wherein the control unit is configured to control the radio frequency power supply and the bias power supply so as to continuously and simultaneously supply the source radio frequency power and the electric bias during a plasma processing period, and to set the power level of the source radio frequency power to 3 kW or less, a bias frequency which is the reciprocal of the time length of a waveform cycle of the electric bias to less than 400 kHz, and a voltage amplitude of the electric bias to 3 kV or more.

2. The plasma processing apparatus according to claim 1, wherein the control unit is configured to control the bias power supply so as to increase the voltage amplitude as time passes during the plasma processing period.

3. The plasma processing apparatus according to claim 1, wherein the control unit is configured to control the bias power supply so as to change the bias frequency as time passes during the plasma processing period.

4. A plasma processing apparatus according to any one of claims 1 to 3, wherein the electrical bias is a voltage pulse that is supplied periodically at a time interval of the waveform period, and the voltage amplitude is the amplitude of the voltage pulse.

5. The plasma processing apparatus according to claim 4, wherein the control unit is configured to control the bias power supply so as to decrease the duty ratio of the voltage pulse in the waveform period as time passes during the plasma processing period.

6. A plasma processing apparatus according to any one of claims 1 to 3, wherein the electrical bias is a bias high frequency power having the bias frequency, and the voltage amplitude is a peak-to-peak voltage of the bias high frequency power.

7. The plasma processing apparatus according to any one of claims 1 to 3, further comprising an exhaust system configured to exhaust gas from the chamber, and the control unit configured to control the exhaust system so as to reduce the pressure in the chamber as time passes during the plasma processing period.

8. A plasma processing apparatus according to any one of claims 1 to 3, wherein the control unit is configured to control the high frequency power supply so as to change the power level of the source high frequency power as time passes during the plasma processing period.

9. A plasma processing apparatus according to any one of claims 1 to 3, further comprising a temperature adjustment mechanism configured to adjust the temperature of the substrate support part, and the control unit configured to control the temperature adjustment mechanism so as to lower the temperature of the substrate support part as time passes during the plasma processing period.

10. A power supply system comprising: a radio frequency power supply configured to supply source radio frequency power to generate plasma from gas in a chamber of a plasma processing apparatus; and a bias power supply configured to supply an electric bias to a substrate support in the chamber to attract ions from the plasma to a substrate on the substrate support, wherein the radio frequency power supply and the bias power supply are configured to continuously and simultaneously supply the source radio frequency power and the electric bias, respectively, during a plasma processing period, the radio frequency power supply is configured to set a power level of the source radio frequency power to 3 kW or less during the plasma processing period, and the bias power supply is configured to set a bias frequency, which is the reciprocal of the time length of a waveform cycle of the electric bias, to less than 400 kHz and a voltage amplitude of the electric bias to 3 kV or more during the plasma processing period.

11. The power supply system of claim 10, wherein the bias power supply is configured to increase the voltage amplitude over time during the plasma processing period.

12. The power supply system of claim 10, wherein the bias power supply is configured to change the bias frequency over time during the plasma processing period.

13. A power supply system according to any one of claims 10 to 12, wherein the electrical bias is a voltage pulse supplied periodically at a time interval of the waveform period, and the voltage amplitude is the amplitude of the voltage pulse.

14. The power supply system of claim 13, wherein the bias power supply is configured to decrease the duty ratio of the voltage pulse in the waveform period as time passes during the plasma processing period.

15. A power supply system according to any one of claims 10 to 12, wherein the electrical bias is bias high frequency power having the bias frequency, and the voltage amplitude is the peak-to-peak voltage of the bias high frequency power.

16. A power supply system according to any one of claims 10 to 12, wherein the RF power supply is configured to vary the power level of the source RF power over time during the plasma processing period.

17. A plasma processing method comprising: (a) a step of continuously supplying source radio frequency power to generate plasma from a gas in a chamber of a plasma processing apparatus during a plasma processing period; and (b) a step of continuously supplying an electric bias to the substrate support member simultaneously with the supply of the source radio frequency power in (a) to attract ions from the plasma to a substrate on the substrate support member in the chamber during the plasma processing period, wherein during the plasma processing period, the power level of the source radio frequency power is set to 3 kW or less, a bias frequency which is the reciprocal of the time length of a waveform cycle of the electric bias is set to less than 400 kHz, and a voltage amplitude of the electric bias is set to 3 kV or more.

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