WO2024106257A1

WO2024106257A1 - Plasma processing apparatus and plasma processing method

Info

Publication number: WO2024106257A1
Application number: PCT/JP2023/039949
Authority: WO
Inventors: 地塩輿水; 友佑人上坂
Original assignee: 東京エレクトロン株式会社
Priority date: 2022-11-18
Filing date: 2023-11-06
Publication date: 2024-05-23

Abstract

The disclosed plasma processing apparatus comprises a chamber, a substrate support, and a high-frequency electric power supply. The substrate support is provided inside the chamber. The high-frequency electric power supply is configured to supply a source high-frequency electric power in a first partial period that includes a startup time of the source high-frequency electric power and a second partial period that follows the first partial period. The high-frequency electric power supply is configured to set a time series of a source frequency of the source high-frequency electric power in the first partial period to a frequency time series that increases gradually or in a stepwise manner from a first frequency to a second frequency that is higher than the first frequency without decreasing.

Description

Plasma processing apparatus and plasma processing method

An exemplary embodiment of the present disclosure relates to a plasma processing apparatus and a plasma processing method.

A plasma processing apparatus is used in plasma processing of a substrate. The plasma processing apparatus generates plasma from a gas in a chamber by supplying source radio frequency power. The plasma processing apparatus uses bias radio frequency power to attract ions from the plasma generated in the chamber to the substrate. The following Patent Document 1 discloses a technique for reducing the duty ratio of a pulse of the source radio frequency power from an initial value used simultaneously with the start of the process to a fixed value used after a predetermined time has elapsed.

JP 2013-122966 A

This disclosure provides a technology that quickly reduces the reflection of source high frequency power.

In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, and a radio frequency power source. The substrate support is disposed within the chamber. The radio frequency power source is electrically coupled to the chamber and configured to generate a source radio frequency power. The radio frequency power source is configured to supply the source radio frequency power during a first subperiod including a rise time of the source radio frequency power and a second subperiod following the first subperiod. The radio frequency power source is configured to set a time series of source frequencies of the source radio frequency power to a time series of frequencies that increase gradually or stepwise without decreasing from a first frequency to a second frequency higher than the first frequency during the first subperiod.

According to one exemplary embodiment, it is possible to rapidly reduce the reflection of source high frequency power.

FIG. 1 is a diagram for explaining a configuration example of a plasma processing system. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. Each of FIG. 4(a) and FIG. 4(b) is a diagram showing an example of the waveform of the electrical bias. 2 is an example timing chart relating to a plasma processing apparatus according to an exemplary embodiment. Each of FIGS. 6A to 6E is a diagram showing a change in source frequency over time in a plasma processing apparatus according to an example embodiment. Each of FIGS. 7A to 7E is a diagram showing a change in source frequency over time in a plasma processing apparatus according to an example embodiment. Each of FIGS. 8A to 8E is a diagram showing a change in source frequency over time in a plasma processing apparatus according to an example embodiment. 1 is a flow diagram of a plasma processing method according to an exemplary embodiment.

Various exemplary embodiments will be described in detail below with reference to the drawings. Note that the same reference numerals will be used to denote the same or equivalent parts in each drawing.

FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas 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 unit 11 is disposed in the plasma processing space, and has a substrate support surface for supporting a substrate.

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). In addition, various types of plasma generating units may be used, including an alternating current (AC) plasma generating unit and a direct current (DC) plasma generating unit.

The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various steps described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various steps described herein. In one embodiment, a part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a memory unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on a program stored in the memory unit 2a2. The memory unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), a SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

Below, an example of the configuration of a capacitively coupled plasma processing apparatus will be described as an example of the plasma processing apparatus 1. Each of Figures 2 and 3 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus.

The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support unit 11. The sidewall 10a is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W, and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a planar 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. In one embodiment, the main body 111 includes a base 111e and an electrostatic chuck 111c. The base 111e includes a conductive member. The conductive member of the base 111e functions as a lower electrode. The electrostatic chuck 111c is disposed on the base 111e. The upper surface of the electrostatic chuck 111c has a substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not shown, the substrate support 11 may include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 111c, the ring assembly 112, and the substrate W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The shower head 13 also includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. In addition to the shower head 13, the gas introduction unit may include one or more side gas injectors (SGI) attached to one or more openings formed in the side wall 10a.

The gas supply unit 20 may include one or more gas sources 21 and at least one or more flow controllers 22. In one embodiment, the gas supply unit 20 is configured to supply one or more process gases from respective gas sources 21 through respective flow controllers 22 to the showerhead 13. 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 one or more flow modulation devices to modulate or pulse the flow rate of one or more process gases.

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 adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

The plasma processing apparatus 1 further includes a power supply system 30. The power supply system 30 includes a high-frequency power supply 31 and a control unit 30c. The power supply system 30 may further include a bias power supply 32. The power supply system 30 may further include one or more sensors 31s.

The high frequency power source 31 is electrically coupled to the chamber (plasma processing chamber 10) and is configured to generate a source high frequency power HF to generate a plasma in the chamber. The source high frequency power HF has a source frequency _fS . The source frequency _fS is, for example, a frequency in the range of 13 MHz or more and 200 MHz or less. The source frequency _fS may be set to 27 MHz, 40.68 MHz, 60 MHz, or 100 MHz. The power level of the source high frequency power HF is, for example, 500 W or more and 20 kW or less.

In one embodiment, the high frequency power supply 31 may include a high frequency signal generator 31g and an amplifier 31a. The high frequency signal generator 31g generates a high frequency signal. The amplifier 31a generates a source high frequency power HF by amplifying the high frequency signal input from the high frequency signal generator 31g, and outputs the source high frequency power HF. The high frequency signal generator 31g may be composed of a programmable processor or a programmable logic device such as an FPGA. A D/A converter may be connected between the high frequency signal generator 31g and the amplifier 31a.

The high frequency power supply 31 is connected to the high frequency electrode via a matching device 31m. In one embodiment, the base 111e constitutes the high frequency electrode. In another embodiment, the high frequency electrode may be an electrode provided in the electrostatic chuck 111c. The high frequency electrode may be an electrode common to a bias electrode described later. Alternatively, the high frequency electrode may be an upper electrode. The matching device 31m includes a matching circuit. The matching circuit of the matching device 31m has a variable impedance. The matching circuit of the matching device 31m is controlled by the control unit 30c. The impedance of the matching circuit of the matching device 31m is adjusted so as to match the impedance of the load side to the output impedance of the high frequency power supply 31. In one embodiment, the impedance of the matching circuit of the matching device 31m when the source high frequency power HF is supplied is set so as to match the impedance of the load side to the output impedance of the high frequency power supply 31 when the plasma is in a steady state in a second partial period _SP2 described later, that is, when the reflection of the source high frequency power HF is suppressed or converged, to the output impedance of the high frequency power supply 31.

One or more sensors 31s may be connected between the high frequency power supply 31 and the matching device 31m. Alternatively, one or more sensors 31s may be connected between the bias electrode and a junction of an electrical path extending from the matching device 31m toward the bias electrode and the bias power supply 32 or an electrical path extending from the matching device 32m described below toward the bias electrode. Alternatively, one or more sensors 31s may be connected between the junction and the matching device 31m. Note that one or more sensors 31s may be a sensor separate from the matching device 31m, or may be part of the matching device 31m.

The one or more sensors 31s may include a directional coupler. The directional coupler is configured to detect the power level of the reflected wave of the source high frequency power HF returned from the load of the high frequency power source 31 and to notify the control unit 30c of the detected power level of the reflected wave.

The one or more sensors 31s may also include a VI sensor configured to detect a voltage _VHF and a current _IHF of the source high frequency power and to determine an impedance _ZL on the load side of the high frequency power supply 31 from the voltage _VHF and the current _IHF . The VI sensor may be configured to determine a phase difference between the voltage _VHF and the current _IHF .

The bias power supply 32 is electrically coupled to the bias electrode. In one embodiment, the base 111e constitutes the bias electrode. In another embodiment, the bias electrode may be an electrode disposed within the electrostatic chuck 111c. The bias power supply 32 is configured to provide an electrical bias EB (or bias energy) to the bias electrode.

Below, reference will be made to Figs. 1 to 3 as well as Figs. 4(a) and 4(b). Each of Figs. 4(a) and 4(b) is a diagram showing an example of an electric bias waveform. The bias power supply 32 is configured to periodically apply an electric bias EB having a waveform period CY to the bias electrode. That is, the electric bias EB is applied to the bias electrode in each of a plurality of waveform periods CY, which are repetitions of the waveform period CY. The waveform period CY is determined by the bias frequency. The bias frequency is, for example, a frequency not less than 50 kHz and not more than 27 MHz. The time length of the waveform period CY is the reciprocal of the bias frequency.

As shown in FIG. 4(a), the electric bias EB may be bias high frequency power LF having a bias frequency. That is, the electric bias EB may have a sinusoidal waveform whose frequency is the bias frequency. In this case, the bias power supply 32 is electrically connected to the bias electrode via a matching device 32m as shown in FIG. 2. The variable impedance of the matching device 32m is set to reduce the reflection of the bias high frequency power LF from the load.

Alternatively, as shown in FIG. 4B, the electric bias EB may include a voltage pulse VP. The voltage pulse VP is applied to the bias electrode within a waveform period CY. The voltage pulse VP is applied to the bias electrode periodically at a time interval the same as the time length of the waveform period CY. 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 to attract ions from the plasma to the substrate W. The voltage pulse VP may be a negative voltage pulse or a negative DC voltage pulse. When the electric bias EB is a voltage pulse VP, the plasma processing apparatus 1 does not include a matching unit 32m as shown in FIG. 3.

As shown in FIG. 2, the bias power supply 32 may include a signal generator 32g and an amplifier 32a. The signal generator 32g generates a signal for generating an electric bias EB from the signal generator 32g. The amplifier 32a generates the electric bias EB by amplifying the signal input from the signal generator 32g, and supplies the generated electric bias EB to the bias electrode. The signal generator 32g may be composed of a programmable processor or a programmable logic device such as an FPGA. A D/A converter may be connected between the signal generator 32g and the amplifier 32a.

When the electric bias EB includes a voltage pulse VP, the bias power supply 32 may include a DC power supply 32d and a switch 32s, as shown in FIG. 3. In this case, the bias power supply 32 generates the voltage pulse VP by switching between outputting and stopping the output of a DC voltage from the DC power supply 32d by opening and closing the switch 32s.

The bias power supply 32 is synchronized with the high frequency power supply 31. A synchronization signal used for this purpose may be provided from the bias power supply 32 to the high frequency power supply 31. Alternatively, the synchronization signal may be provided from the high frequency power supply 31 to the bias power supply 32. Alternatively, the synchronization signal may be provided to the high frequency power supply 31 and the bias power supply 32 from another device such as the control unit 30c.

In one embodiment, the high frequency power supply 31 may be configured to supply a pulse of source high frequency power HF to the high frequency electrode. The pulse of source high frequency power HF may be supplied periodically. The bias power supply 32 may be configured to supply a pulse of electric bias EB to the bias electrode. The pulse of electric bias EB may be supplied periodically. In this case, each of the high frequency power supply 31 and the bias power supply 32 may specify the pulse supply period by a signal provided from the pulse controller 34. The control unit 2 may function as the pulse controller 34. The pulse controller 34 may be part of the high frequency power supply 31.

The control unit 30c is configured to control the high frequency power supply 31. The control unit 30c may further control the bias power supply 32. The control unit 30c may be configured with a processor such as a CPU. The control unit 30c may be part of the matching device 31m, may be part of the high frequency power supply 31, or may be a control unit separated from the matching device 31m and the high frequency power supply 31. Alternatively, the control unit 2 may also function as the control unit 30c. The control unit 30c may also function as the pulse controller 34.

Refer to FIG. 5 below. FIG. 5 is an example timing chart related to a plasma processing apparatus according to an exemplary embodiment. FIG. 5 shows a timing chart of the source high frequency power HF and the electric bias EB. In FIG. 5, "ON" of the source high frequency power HF indicates that the source high frequency power HF is being supplied, and "OFF" of the source high frequency power HF indicates that the supply of the source high frequency power HF is stopped. In FIG. 5, "LOW" of the source high frequency power HF indicates that the power level of the source high frequency power HF is lower than the power level of the source high frequency power HF indicated by "HIGH". Also, in FIG. 5, "ON" of the electric bias EB indicates that the electric bias EB is being supplied, and "OFF" of the electric bias EB indicates that the supply of the electric bias EB is stopped.

As shown in FIG. 5, the high frequency power supply 31 is configured to supply source high frequency power HF in a first partial period _SP1 and a second partial period _SP2 . The first partial period _SP1 is a period including the rising time of the source high frequency power HF. The rising time of the source high frequency power HF is the start of the supply of the source high frequency power HF or the start of the supply of a pulse HFP of the source high frequency power HF described later. The second partial period _SP2 is a period following the first partial period _SP1 . The length of the first partial period _SP1 is shorter than the length of the second partial period _SP2 . The length of the first partial period _SP1 is the same as the time length of the waveform period CY or longer than the waveform period CY. The length of the first partial period _SP1 may be 10 μs or less.

In one embodiment, the high frequency power supply 31 may supply the source high frequency power HF (i.e., its pulse HFP) in a first period _P1 as shown in FIG. 5. The first period _P1 is a period including a first partial period _SP1 and a second partial period _SP2 . The high frequency power supply 31 may also stop supplying the source high frequency power HF in a second period _P2 alternating with the first period _P1 . Alternatively, the high frequency power supply 31 may set the power level of the source high frequency power HF in the second period _P2 to a level lower than the power level of the source high frequency power HF (pulse HFP) in the first period _P1 . In this way, the high frequency power supply 31 may periodically supply the pulse HFP of the source high frequency power HF.

In another embodiment, the high frequency power supply 31 may continuously supply the source high frequency power HF, i.e., the high frequency power supply 31 may continuously supply the source high frequency power HF in a single period including the first sub-period _SP1 and the second sub-period _SP2 .

In one embodiment, the bias power supply 32 may supply a pulse EBP of the electric bias EB to the substrate support 11 (i.e., the bias electrode) in the second period _P2 . That is, the bias power supply 32 may supply the pulse EBP periodically. During the period in which the pulse EBP is supplied, the waveform period CY is repeated. The supply of the pulse EBP may be started at or after the start of the second period _P2 . Alternatively, the supply of the pulse EBP may be started from a time between the start and end of the second partial period _SP2 .

As shown in (a) to (e) of Figure 6, (a) to (e) of Figure 7, and (a) to (e) of Figure 8, the high frequency power supply 31 changes the source frequency _fS of the source high frequency power HF in the first partial period _SP1 . Each of (a) to (e) of Figure 6, (a) to (e) of Figure 7, and (a) to (e) of Figure 8 is a diagram showing a time change of the source frequency in a plasma processing apparatus according to an example embodiment.

Specifically, as shown in (a) to (e) of Figures 6, (a) to (e) of Figures 7, and (a) to (e) of Figures 8, the high frequency power supply 31 sets the time series of the source frequency _fS to a time series of frequencies that gradually or stepwise increase from the first frequency _f1 to the second frequency _f2 _{during the frequency increase period P U} _in the first partial period _SP1 . The high frequency power supply 31 may gradually or stepwise increase the source frequency _fS from the first frequency _f1 to the second frequency _f2 without decreasing the source frequency _fS during the frequency increase period P U. The high frequency power supply 31 may obtain the time series of the source frequency _fS used during the frequency increase period P _U by interpolation using one or more straight lines or curves for the first frequency _f1 and the second frequency _f2 .

6A to 6E, the frequency increase period P _U may be the same as the first partial period SP _1. That is, the start point of the first partial period SP ₁ may be the same as the start point of the frequency increase period P _U , and the end point of the first partial period SP ₁ may be the same as the end point of the frequency increase period P _U. In this case, the source frequency f _S is set to the first frequency f ₁ at the start point of the first partial period SP ₁ and is increased to the second frequency f ₂ in the first partial period SP ₁ .

As shown in (a) to (e) of FIG. 7 and (a) to (e) of FIG. 8, the first partial period SP ₁ may include a start period P _S before the frequency increase period P _U. The start period P _S may include the start point of the first partial period SP _1. As shown in (a) to (e) of FIG. 7, the source frequency f _S may be maintained at a frequency f ₀ in the start period P _S. As shown in (a) to (e) of FIG. 8, the source frequency f _S may be decreased from a frequency f ₀ to a first frequency f ₁ in the start period P _S. The frequency f ₀ may be greater than the second frequency f _2. The frequency f ₀ may be a resonant frequency of the source high frequency power HF for the chamber 10 when no plasma is generated in the chamber 10. In this case, discharge is likely to occur in the start period P _S. It should be noted that, among the multiple first periods _P1 that are repetitions of the first period _P1 , only the first partial period _SP1 in the first first period _P1 may include the start period _PS , and the other first periods _P1 may include only the frequency increase period _PU .

In the examples shown in Fig. 6(a), Fig. 7(a), and Fig. 8(a), the time series of the source frequency _fS in the frequency increase period P _U is set by interpolation using one curve for the first frequency _f1 and the second frequency _f2 . In the examples shown in Fig. 6(b), Fig. 7(b), and Fig. 8(b), the time series of the source frequency _fS in the frequency increase period P _U is set by interpolation using two straight lines for the first frequency _f1 , the second frequency _f2 , and an intermediate frequency between the first frequency _f1 and the second frequency _f2 . In the examples shown in Fig. 6(c), Fig. 7(c), and Fig. 8(c), the time series of the source frequency _fS in the frequency increase period P _U is set by interpolation using one straight line for the first frequency _f1 and the second frequency _f2 . In the examples shown in each of FIGS. 6(d), 6(e), 7(d), 7(e), 8(d), and 8(e), the time series of the source frequency _fS in the frequency increase period _PU is set to a time series of frequencies that increase stepwise from a first frequency _f1 to a second frequency _f2 .

The time series of the source frequency _fS used in the first partial period _SP1 in each of the multiple first periods _P1 that are repetitions of the first period _P1 may be the same as the time series of the source frequency _fS used in the first partial period _SP1 in each of all other first periods _P1 . That is, in an embodiment in which the pulses HFP of the source high frequency power HF are periodically supplied, the same time series of the source _frequency _fS may be used in the first partial period _SP1 of each of the multiple first periods _P1 . Alternatively, the time series of the source frequency _fS used in the first partial period _SP1 in each of all first periods except the first first period among the multiple first periods P1 may be the same as the time series of the source frequency _fS used in the first partial period _SP1 in each of the other first periods among all first periods except the first first period. That is, the same time series of the source frequency f _{S may be used in the first partial periods SP 1 of all first periods P 1 except for the first first period among the multiple first periods P 1. Alternatively, the time series of the source frequency f S} _used _in _the _first partial periods SP _{1 in each of the multiple first periods P 1} _may be changed by inter-pulse feedback, which will be described later.

The high frequency power supply 31 may fix the source frequency _fS for at least a predetermined time from the start of the second partial period _SP2 . The high frequency power supply 31 may fix the source frequency _fS to the second frequency _f2 for at least a predetermined time from the start of the second partial period _SP2 . The high frequency power supply 31 may fix the source frequency _fS throughout the entire second partial period _SP2 . The high frequency power supply 31 may fix the source frequency _fS in the second partial period _SP2 to the second frequency _f2 .

The inter-pulse feedback will be described below. In the following description, the first sub-period _SP1 [n] represents the first sub-period _SP1 in the n _- th first period _P1 in the repetition of the first period _P1 , i.e., the repetition of the multiple first periods P1. Also, _αm represents a time point m hours after the start of the first sub-period _SP1 . Also, the source frequency _fS [ _SP1 [n], _αm ] represents the source frequency _fS used at time point _αm of the first sub-period _SP1 [n].

In the pulse-to-pulse feedback, the degree of reflection of the source high frequency power is utilized. The degree of reflection may be obtained as the power level of the reflected wave of the source high frequency power HF. The degree of reflection may be obtained as the value of 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 or the set output power level of the source high frequency power HF. Alternatively, the degree of reflection may be obtained as the deviation amount of the impedance _ZL with respect to the characteristic impedance (e.g., 50Ω) of the power line of the source high frequency power HF to the high frequency electrode. Alternatively, the degree of reflection may be obtained as the phase difference between the voltage _VHF and the current _IHF . Alternatively, the degree of reflection may be obtained as another quantity representing the degree of matching to the plasma at the source frequency _fS . In either case, the degree of reflection may be obtained by one or more sensors 31s or may be determined from measurements obtained by one or more sensors 31s.

In the pulse-to-pulse feedback, the control unit 30c sets the source frequency _fS [ _SP1 [n _] , _αm ] so as to suppress the degree of reflection of the source high frequency power HF at the time _αm in the first partial period _SP1 [n] in accordance with the change from the source frequency _fS [ _SP1 [n-q], _αm ] at the same time _αm in the first partial period _SP1 [n-q] to _fS [ _SP1 [n-p], αm] at the same time _αm in the first partial period _SP1 [n-p] and the change from the degree of reflection of the source high frequency power HF at the same time _αm in the first partial period _SP1 [n-q] to the degree of reflection of the source high frequency power HF at the same time _αm in the first partial period _SP1 [n-p]. Here, q and p are integers equal to or greater than 1, and q is greater than p. For example, q is 2 and p is 1.

In one example, if the change from the degree of reflection of the source high frequency power HF at time _αm in the first sub-period SP ₁ [n-q] to the degree of reflection of the source high frequency power HF at time _αm in the first sub-period SP ₁ [n-p] is a decrease in the degree of reflection, the control unit 30c sets the source frequency f _S [SP ₁ [n], α _m ] to a frequency that gives the source frequency f _S [SP ₁ [n-p], α _m ] a change in the same direction as the change from the source frequency f _S [SP ₁ [n-q], α _m ] to the source frequency f _S [SP ₁ [n-p], α _m ]. If the change from the degree of reflection of the source high frequency power HF at time _αm in the first partial period SP ₁ [n-q] to the degree of reflection of the source high frequency power HF at time _αm in the first partial period SP ₁ [n-p] is an increase in the degree of reflection, the control unit 30c sets the frequency obtained by giving the source frequency f _S [SP ₁ [n-p], α _m ] a change in the opposite direction to the change from the source frequency _f _S [SP ₁ [n-q], α _m ] to the source frequency f S [SP ₁ [n-p], α _m ] as the source frequency f _S [SP ₁ [n], α _m ].

As described above, in the plasma processing apparatus 1, the source frequency _fS is gradually or stepwise increased in the first partial period _SP1 . That is, in the first partial period _SP1 , a low source frequency _fS is initially used. The coupling efficiency of the source high frequency power HF having the low source frequency _fS to the plasma is high when the thickness of the plasma sheath is small. Therefore, in this case, it is possible to shorten the time from the rise of the source high frequency power HF to the reduction or convergence of the reflection of the source high frequency power HF.

Below, a plasma processing method according to one exemplary embodiment will be described with reference to FIG. 9. FIG. 9 is a flow chart of a plasma processing method according to one exemplary embodiment. The plasma processing method shown in FIG. 9 (hereinafter, referred to as "method MT") can be performed with a substrate placed on a substrate support 11. To perform each step of method MT, each part of the plasma processing apparatus 1 can be controlled by a controller 2.

The method MT starts with step STa. In step STa, a source high frequency power HF or a pulse HFP thereof is supplied to generate plasma from a gas in the chamber 10. As described above, the source high frequency power HF or a pulse HFP thereof is supplied in the first partial period _SP1 and the second partial period _SP2 . Note that a gas is supplied from the gas supply unit 20 into the chamber. Also, the pressure in the chamber 10 is adjusted by the exhaust system 40.

The process STb is performed in the first partial period SP _1. In the process STb, as described above, the time series of the source frequency f _S is set to a time series of frequencies that gradually or stepwise increase from the first frequency f ₁ to the second frequency f ₂ .

Then, the process STc is performed. In the process STc, the source frequency f _S in the second partial period _SP2 is set. As described above, the source frequency f _S may be fixed for at least a predetermined time from the start of the second partial period _SP2 . The source frequency f _S may be fixed to the second frequency f ₂ for at least a predetermined time from the start of the second partial period _SP2 . The source frequency f _S may be fixed throughout the entire second partial period _SP2 . The source frequency f _S in the second partial period _SP2 may be fixed to the second frequency f ₂ .

In one embodiment, as described above, the first period _P1 and the second period _P2 are alternately repeated. A pulse HFP is supplied in the first period _P1 . In this embodiment, the method MT further includes a step STd. In the step STd, a pulse EBP of the electric bias EB is supplied. The pulse EBP is supplied in the second period _P2 . As described above, the supply of the pulse EBP may be started at or after the start of the second period _P2 . Alternatively, the supply of the pulse EBP may be started from a time between the start and end of the second partial period _SP2 .

In one embodiment, the method MT further includes a step STJ. In the step STJ, it is determined whether a stop condition is satisfied. The stop condition is satisfied when the number of times that the first period _P1 and the second period _P2 are alternately repeated reaches a predetermined number. If the stop condition is not satisfied, the process from step STa is performed again. On the other hand, if the stop condition is satisfied, the method MT ends.

Various exemplary embodiments have been described above, but the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. In addition, elements in different embodiments can be combined to form other embodiments.

In another embodiment, 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 the plasma processing apparatuses, a source high frequency power HF is used to generate the plasma.

Various exemplary embodiments included in this disclosure are described below in [E1] to [E15].

[E1]
A chamber;
a substrate support disposed within the chamber;
a radio frequency power source electrically coupled to the chamber and configured to generate a source radio frequency power;
Equipped with
The high frequency power source is
supplying the source high frequency power in a first subperiod including a rising edge of the source high frequency power and a second subperiod following the first subperiod;
In the first partial period, a time series of source frequencies of the source high frequency power is set to a time series of frequencies that increase gradually or stepwise without decreasing from a first frequency to a second frequency higher than the first frequency.
The plasma processing apparatus is configured as follows.

[E2]
The plasma processing apparatus of claim E1, wherein the length of the first partial period is 10 μsec or less.

[E3]
The plasma processing apparatus of E1 or E2, wherein the source frequency is fixed at the second frequency during the second partial period.

[E4]
a bias power supply electrically coupled to the substrate support and configured to generate an electrical bias to attract ions to the substrate support;
The high frequency power source is
providing the source radio frequency power during a first period including the first period sub-period and the second period sub-period;
during second periods alternating with the first periods, supply of the source high frequency power is stopped or a power level of the source high frequency power is set to a level lower than a power level of the source high frequency power during the first periods,
periodically providing pulses of said source radio frequency power;
the bias power supply is configured to periodically supply pulses of the electrical bias to the substrate support by supplying the electrical bias to the substrate support during the second period of time.
The plasma processing apparatus according to any one of E1 to E3.

[E5]
The plasma processing apparatus of E4, wherein the time series of the source frequencies used in the first partial period in each of a plurality of first periods that are repetitions of the first period is identical to the time series of the source frequencies used in the first partial period in each of all other first periods among the plurality of first periods.

[E6]
The plasma processing apparatus described in E4, wherein the time series of the source frequency used in the first partial period in each of all first periods except for a first first period among a plurality of first periods that are repetitions of the first period is identical to the time series of the source frequency used in the first partial period in each of the other first periods among all the first periods except for the first first period.

[E7]
The plasma processing apparatus according to any one of claims E1 to E6, wherein the high frequency power supply is configured to obtain the time series of the source frequency used in the first partial period by interpolation using one or more straight lines or curves for the first frequency and the second frequency.

[E8]
A chamber;
a substrate support disposed within the chamber;
a radio frequency power source electrically coupled to the chamber and configured to generate a source radio frequency power;
Equipped with
The high frequency power source is
supplying the source high frequency power in a first subperiod including a rising edge of the source high frequency power and a second subperiod following the first subperiod;
During the first partial period, a time series of source frequencies of the source high frequency power is set to a time series of frequencies that gradually or stepwise increase from a first frequency to a second frequency higher than the first frequency;
during the second sub-period, fixing the source frequency at the second frequency for a predetermined time from a start of the second sub-period;
The plasma processing apparatus is configured as follows.

[E9]
The plasma processing apparatus of E8, wherein the length of the first sub-period is 10 μsec or less.

[E10]
The plasma processing apparatus of any one of E8 and E9, wherein the source frequency is fixed at the second frequency during the second sub-period.

[E11]
a bias power supply electrically coupled to the substrate support and configured to generate an electrical bias to attract ions to the substrate support;
The high frequency power source is
providing the source radio frequency power during a first period including the first period sub-period and the second period sub-period;
during second periods alternating with the first periods, supply of the source high frequency power is stopped or a power level of the source high frequency power is set to a level lower than a power level of the source high frequency power during the first periods,
periodically providing pulses of said source radio frequency power;
the bias power supply is configured to periodically supply pulses of the electrical bias to the substrate support by supplying the electrical bias to the substrate support during the second period of time.
The plasma processing apparatus according to any one of E8 to E10.

[E12]
The plasma processing apparatus of E11, wherein the time series of the source frequencies used in the first partial period in each of a plurality of first periods that are repetitions of the first period is identical to the time series of the source frequencies used in the first partial period in each of all other first periods among the plurality of first periods.

[E13]
The plasma processing apparatus described in E11, wherein the time series of the source frequency used in the first partial period in each of all first periods except for a first first period among a plurality of first periods that are repetitions of the first period is identical to the time series of the source frequency used in the first partial period in each of the other first periods among all the first periods except for the first first period.

[E14]
The plasma processing apparatus according to any one of E8 to E13, wherein the high frequency power supply is configured to obtain the time series of the source frequency used in the first partial period by interpolation using one or more straight lines or curves for the first frequency and the second frequency.

[E15]
(a) supplying source radio frequency power from a radio frequency power supply to generate plasma in a chamber of a plasma processing apparatus, the source radio frequency power being supplied during a first partial period including a rise time of the source radio frequency power and a second partial period subsequent to the first partial period;
(b) during the first partial period, setting a time series of source frequencies of the source high frequency power to a time series of frequencies that increase gradually or stepwise without decreasing from a first frequency to a second frequency higher than the first frequency;
A plasma processing method comprising:

From the foregoing, it will be understood that the 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.

1: Plasma processing device, 2: Control unit, 10: Plasma processing chamber, 11: Substrate support unit, 31: High frequency power supply, 32: Bias power supply.

Claims

A chamber;
a substrate support disposed within the chamber;
a radio frequency power source electrically coupled to the chamber and configured to generate a source radio frequency power;
Equipped with
The high frequency power source is
supplying the source high frequency power in a first subperiod including a rising edge of the source high frequency power and a second subperiod following the first subperiod;
In the first partial period, a time series of source frequencies of the source high frequency power is set to a time series of frequencies that increase gradually or stepwise without decreasing from a first frequency to a second frequency higher than the first frequency.
The plasma processing apparatus is configured as follows.
The plasma processing apparatus of claim 1, wherein the length of the first partial period is 10 μsec or less.
The plasma processing apparatus of claim 1, wherein the source frequency is fixed to the second frequency during the second partial period.
a bias power supply electrically coupled to the substrate support and configured to generate an electrical bias to attract ions to the substrate support;
The high frequency power source is
providing the source radio frequency power during a first period including the first period sub-period and the second period sub-period;
during second periods alternating with the first periods, supply of the source high frequency power is stopped or a power level of the source high frequency power is set to a level lower than a power level of the source high frequency power during the first periods,
providing periodic pulses of said source radio frequency power;
the bias power supply is configured to periodically supply pulses of the electrical bias to the substrate support by supplying the electrical bias to the substrate support during the second period of time.
The plasma processing apparatus according to any one of claims 1 to 3.
The plasma processing apparatus of claim 4, wherein the time series of the source frequency used in the first partial period in each of a plurality of first periods that are repetitions of the first period is the same as the time series of the source frequency used in the first partial period in each of all other first periods of the plurality of first periods.
The plasma processing apparatus according to claim 4, wherein the time series of the source frequency used in the first partial period in each of all first periods except for the first first period among the multiple first periods that are repetitions of the first period is the same as the time series of the source frequency used in the first partial period in each of the other first periods among all first periods except for the first first period.
The plasma processing apparatus according to any one of claims 1 to 3, wherein the high frequency power supply is configured to obtain the time series of the source frequency used in the first partial period by interpolation using one or more straight lines or curves for the first frequency and the second frequency.
A chamber;
a substrate support disposed within the chamber;
a radio frequency power source electrically coupled to the chamber and configured to generate a source radio frequency power;
Equipped with
The high frequency power source is
supplying the source high frequency power in a first subperiod including a rising edge of the source high frequency power and a second subperiod following the first subperiod;
During the first partial period, a time series of source frequencies of the source high frequency power is set to a time series of frequencies that gradually or stepwise increase from a first frequency to a second frequency higher than the first frequency;
during the second sub-period, fixing the source frequency at the second frequency for a predetermined time from a start of the second sub-period;
The plasma processing apparatus is configured as follows.
The plasma processing apparatus of claim 8, wherein the length of the first partial period is 10 μsec or less.
The plasma processing apparatus of claim 8, wherein the source frequency is fixed to the second frequency during the second partial period.
a bias power supply electrically coupled to the substrate support and configured to generate an electrical bias to attract ions to the substrate support;
The high frequency power source is
providing the source radio frequency power during a first period including the first period sub-period and the second period sub-period;
during second periods alternating with the first periods, supply of the source high frequency power is stopped or a power level of the source high frequency power is set to a level lower than a power level of the source high frequency power during the first periods,
periodically providing pulses of said source radio frequency power;
the bias power supply is configured to periodically supply pulses of the electrical bias to the substrate support by supplying the electrical bias to the substrate support during the second period of time.
The plasma processing apparatus according to any one of claims 8 to 10.
The plasma processing apparatus of claim 11, wherein the time series of the source frequency used in the first partial period in each of a plurality of first periods that are repetitions of the first period is the same as the time series of the source frequency used in the first partial period in each of all other first periods of the plurality of first periods.
The plasma processing apparatus according to claim 11, wherein the time series of the source frequency used in the first partial period in each of all first periods except for the first first period among the multiple first periods that are repetitions of the first period is the same as the time series of the source frequency used in the first partial period in each of the other first periods among all first periods except for the first first period.
The plasma processing apparatus according to any one of claims 8 to 10, wherein the high frequency power supply is configured to obtain the time series of the source frequency used in the first partial period by interpolation using one or more straight lines or curves for the first frequency and the second frequency.
(a) supplying source radio frequency power from a radio frequency power supply to generate plasma in a chamber of a plasma processing apparatus, the source radio frequency power being supplied during a first partial period including a rise time of the source radio frequency power and a second partial period following the first partial period;
(b) during the first partial period, setting a time series of source frequencies of the source radio frequency power to a time series of frequencies that increase gradually or stepwise without decreasing from a first frequency to a second frequency higher than the first frequency;
A plasma processing method comprising: