Plasma processing apparatus and control method

Abstract

Provided are a plasma processing apparatus and a control method for ascertaining a state of plasma.　The plasma processing apparatus comprises: a plasma processing chamber; a base disposed in the plasma processing chamber; an electrostatic chuck disposed on an upper portion of the base and including a plurality of divided regions; an attraction electrode disposed in the electrostatic chuck; a heater electrode disposed below the attraction electrode for each of the plurality of divided regions; a heater power supply electrically connected to the heater electrode; a surface potential measurement device electrically connected to the attraction electrode and having a surface potential meter; and a control unit, wherein the control unit calculates a plasma state from a set value of power applied to the heater electrode from the heater power supply and a potential measured by the surface potential meter.

Description

Plasma processing apparatus and control method

[0001] The present disclosure relates to a base and a plasma processing apparatus.

[0002] Japanese Patent Application Laid-Open No. 2003-144222 discloses a plasma processing apparatus having a measuring device for measuring a self-bias voltage.

[0003] Japanese Patent Application Laid-Open No. 2019-40853

[0004] In one aspect, the present disclosure provides a plasma processing apparatus and a control method for grasping a plasma state.

[0005] In order to achieve the above object, according to one aspect, there is provided a plasma processing apparatus including: a plasma processing chamber; a base disposed within the plasma processing chamber; an electrostatic chuck disposed on an upper portion of the base and including a plurality of divided regions; an attraction electrode disposed within the electrostatic chuck; heater electrodes disposed below the attraction electrode for each of the plurality of divided regions; a heater power supply electrically connected to the heater electrode; a surface potential measuring device electrically connected to the attraction electrode and having a surface potential meter; and a controller, wherein the controller calculates a state of plasma from a set value of power applied from the heater power supply to the heater electrode and a potential measured by the surface potential meter.

[0006] According to one aspect, it is possible to provide a plasma processing apparatus and a control method for grasping the state of plasma.

[0007] An example of a diagram for explaining an example of the configuration of a plasma processing system. An example of a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. An example of a diagram schematically showing a cross section of an electrostatic chuck. An example of a diagram schematically showing a top view of an electrostatic chuck. An example of a flowchart showing a method for controlling a plasma processing system. An example of a graph showing trends in plasma state versus recipe parameters.

[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] [Plasma Processing System] FIG. 1 is an example diagram illustrating an example configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[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 (ECR) plasma, helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generating units may be used, including alternating current (AC) plasma generating units and direct current (DC) plasma generating units. 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. Therefore, AC signals include RF (Radio Frequency) 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 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, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 is realized by, for example, a computer 2a. The control unit 2 may include a processing unit 2a1, a memory unit 2a2, and a communication interface 2a3. The functions performed by the processing unit 2a1 described in this disclosure may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuitry, and / or combinations thereof, programmed to perform the described functions. A processor is considered to be a circuit or processing circuit including transistors and other circuitry. The processor may also be a programmed processor that executes a program stored in the memory unit 2a2. This program may be stored in the memory 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 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).In this disclosure, a circuit, unit, or means is hardware that is programmed to implement or configured to implement a described function. The hardware may be any hardware described in this disclosure or any hardware that is programmed to implement or known to implement the described function. If the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0012] [Plasma Processing Apparatus] A configuration example of a capacitively coupled plasma processing apparatus will be described below as an example of the plasma processing apparatus 1. Fig. 2 is an example of a diagram for explaining a configuration example of the capacitively coupled plasma processing apparatus (substrate processing apparatus) 1.

[0013] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The 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 may function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a, an electrostatic chuck electrode 1111b disposed within the ceramic member 1111a, and a heater electrode 1111c disposed within the ceramic member 1111a. The electrostatic chuck electrode 1111b is also referred to as a clamping electrode. In one embodiment, the electrostatic chuck electrode 1111b is electrically connected or coupled to a chuck power supply 80 (see FIG. 3 , which will be described later). The chuck power supply 80 may be a DC power supply or an AC power supply. Note that FIG. 3 , which will be described later, will be used to describe a case in which the chuck power supply 80 is a DC power supply.

[0016] The heater electrode 1111c is electrically connected or coupled to a heater power supply 60 (see FIG. 3, which will be described later). The heater electrode 1111c is disposed below the electrostatic chuck electrode 1111b. In other words, the electrostatic chuck electrode 1111b is disposed closer to the substrate support surface (central region 111a) than the heater electrode 1111c.

[0017] The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may also have the annular region 111b. 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 bias electrode electrically connected or coupled to the power source 31 and / or the power source 32 (described below) may be disposed within the ceramic member 1111a. In this case, the at least one bias electrode functions as a lower electrode. Furthermore, the conductive member of the base 1110 and the bias electrode within the ceramic member 1111a may function as multiple lower electrodes. In one embodiment, the first voltage generating unit 32a, which functions as a voltage pulse generating unit (described later), is electrically connected or coupled to a bias electrode in the ceramic member 1111a, and the first RF generating unit 31a, which will be described later, is electrically connected or coupled to a conductive member of the base 1110. Also, the electrostatic chuck electrode 1111b may function as a lower electrode. Thus, the substrate support 11 includes at least one lower electrode.

[0018] 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.

[0019] 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 W to a target temperature. The temperature adjustment module may include a heater (including a heater electrode 1111c), 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.

[0020] 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.

[0021] 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.

[0022] The power supply system 30 includes a power supply 31 electrically connected or coupled to the plasma processing chamber 10. In one embodiment, the power supply 31 is electrically connected or coupled to the plasma processing chamber 10 via at least one impedance matcher. The impedance matcher may be a mechanically controlled matcher or an electronically controlled matcher. The 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 plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the 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.

[0023] The power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is electrically connected or coupled to at least one lower electrode and / or at least one upper electrode and is configured to generate a source RF signal (source RF power) to generate plasma in the plasma processing space 10s. In one embodiment, the first RF generator 31a is electrically connected or coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matcher. 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 generator 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.

[0024] The second RF generator 31b is electrically connected or coupled to at least one lower electrode and configured to generate a bias RF signal (bias RF power). In one embodiment, the second RF generator 31b is electrically connected or coupled to at least one lower electrode via at least one impedance matcher. When the first RF generator 31a is electrically connected or coupled to a lower electrode, the second RF generator 31b may be electrically connected or coupled to the same lower electrode or to another lower electrode. 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.

[0025] The power supply system 30 may also include a power supply 32 electrically connected or coupled to the plasma processing chamber 10. The power supply 32 includes a first voltage generator 32a and a second voltage generator 32b. In one embodiment, the first voltage generator 32a is electrically connected or coupled to at least one lower electrode and configured to generate a first voltage signal. The generated first voltage signal is applied to the at least one lower electrode. In one embodiment, the second voltage generator 32b is electrically connected or coupled to at least one upper electrode and configured to generate a second voltage signal. The generated second voltage signal is applied to the at least one upper electrode.

[0026] In various embodiments, the first and / or second voltage signals may be pulsed. In this case, the first voltage generator 32a and / or the second voltage generator 32b function as a voltage pulse generator configured to generate a sequence of voltage pulses. Thus, the sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. In one embodiment, the sequence of voltage pulses includes multiple cycles, each cycle including a burst of voltage pulses during a first period and a constant reference voltage during a second period. That is, the bursts of voltage pulses are repeated in the sequence of voltage pulses. The absolute value of the voltage level of the voltage pulses is greater than the absolute value of the voltage level of the reference voltage. The voltage pulses may have an arbitrary waveform, such as a rectangular, trapezoidal, triangular, or combination thereof, and the arbitrary waveform may vary over time. The voltage pulses may have either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses within one cycle. The first and second voltage generating units 32a and 32b may be provided in addition to the power supply 31, or the first voltage generating unit 32a may be provided instead of the second RF generating unit 31b.

[0027] 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.

[0028] Next, the electrostatic chuck 1111 will be further described with reference to Fig. 3 and Fig. 4. Fig. 3 is an example of a diagram schematically showing a cross section of the electrostatic chuck 1111. Fig. 4 is an example of a diagram schematically showing a top view of the electrostatic chuck 1111.

[0029] The ceramic member 1111a of the electrostatic chuck 1111 includes a plurality of heater electrodes 1111c below the electrostatic chuck electrode 1111b. As shown in FIG. 4 , the top surface of the electrostatic chuck 1111 is divided into a plurality of divided regions (also referred to as zones) Z. A heater electrode 1111c is embedded in each divided region Z of the electrostatic chuck 1111. The heater electrodes 1111c individually control the temperatures of the divided regions Z. This improves the temperature uniformity of the substrate W on the electrostatic chuck 1111. A heater power supply 60 is connected to each heater electrode 1111c via wiring. The heater power supply 60 applies AC power to each heater electrode 1111c according to a set voltage, a set frequency, and a set duty ratio. Note that the heater electrode 1111c does not necessarily have to be divided into a plurality of regions. In this case, the heater electrode 1111c may be the same size as the electrostatic chuck electrode 1111b, or may be a different size.

[0030] The electrostatic chuck electrode 1111b is connected to a surface potential measuring device 70 via wiring. The surface potential measuring device 70 is configured to measure a self-bias voltage Vdc applied to the substrate W.

[0031] [Measurement of Self-Bias Voltage Vdc by Surface Potential Measuring Device 70] Here, the configuration for measuring the self-bias voltage Vdc by using the surface potential measuring device 70 will be further described with reference to FIG.

[0032] The electrostatic chuck electrode 1111b is connected to the surface potential measuring device 70 and the chuck power supply 80 via a relay box 81. The relay box 81 switches the connection destination of the electrostatic chuck electrode 1111b.

[0033] When the switch 81a of the relay box 81 is switched to the connected state (Close or On), the electrostatic chuck electrode 1111b is connected to the chuck power supply 80. This allows a DC voltage to be supplied from the chuck power supply 80 to the electrostatic chuck electrode 1111b, causing the substrate W to be attracted and held by the electrostatic chuck 1111. Note that when the switch 81a is in the connected state (Close or On), the electrostatic chuck electrode 1111b is connected to the surface potential measuring device 70. Note that when the switch 81a is in the connected state (Close or On), the electrostatic chuck electrode 1111b and the surface potential measuring device 70 do not necessarily have to be connected to each other.

[0034] When the switch 81a of the relay box 81 is switched to an open state (Open or Off), the electrostatic chuck electrode 1111b is disconnected from the chuck power supply 80 and connected to the surface potential measuring device 70. This causes the electrostatic chuck electrode 1111b to be in a floating state. The surface potential measuring device 70 measures a voltage V2, which will be described later. The control unit 2 calculates the self-bias voltage Vdc based on the measured voltage V2.

[0035] Here, an example of the configuration of the surface potential measuring device 70 will be described. The surface potential measuring device 70 has a filter 71, a copper disk 72, a copper plate 73, an acrylic plate 74, a probe 75, a surface potential meter 76, and a signal recording device 77. The probe 75 and the surface potential meter 76 constitute a potential measurement system 78.

[0036] The relay box 81 switches the connection of the electrostatic chuck electrode 1111b between the chuck power supply 80 and a capacitive member of the surface potential measuring device 70. The relay box 81 connects a switch 81a of the relay box 81 to the surface potential measuring device 70 (in other words, disconnects the electrode from the chuck power supply 80) when measuring the self-bias voltage Vdc. The relay box 81 is an example of a switching unit that switches the connection of the electrostatic chuck electrode 1111b, to which high-frequency power is applied, to a capacitive member. The member having the acrylic plate 74 sandwiched between the copper disk 72 and the copper plate 73 is an example of a capacitive member. The capacitive member is not limited to the copper disk 72, copper plate 73, and acrylic plate 74, but may be formed of an insulated conductor.

[0037] In the potential measurement system 78, the potential generated on the acrylic plate 74 between the copper disk 72 and the copper plate 73 is measured by a surface electrometer 76 using a probe 75 provided on the surface of the copper disk 72 without contacting it. The potential measurement system 78 is an example of a measurement unit that measures a value corresponding to the amount of charge accumulated in a member having capacitance. The probe 75 may be in contact with the copper disk 72 or may be non-contact, as long as it can measure the potential difference between the copper disk 72 and the copper plate 73.

[0038] A filter 71 that removes high-frequency power is provided between the relay box 81 and the member having capacitance to prevent the high-frequency power from propagating to the surface potential measuring device 70. When the switch 81 a of the relay box 81 is switched from the side connected to the chuck power supply 80 to the side connected to the member having capacitance of the surface potential measuring device 70 (in other words, the connection to the chuck power supply 80 is interrupted), it becomes possible to measure the voltage V2 generated in the member having capacitance, that is, the voltage V2 of the electrostatic chuck electrode 1111 b in the floating state.

[0039] Specifically, the copper plate 73 is grounded, and a potential measured by a surface electrometer 76 using a probe 75 provided in a non-contact manner on the surface of the copper disk 72 is the voltage V2 of the electrostatic chuck electrode 1111b in the floating state. The diameter of the copper disk 72 may be, for example, about 100 mm, but is not limited to this.

[0040] The voltage V2 measured by the surface electrometer 76 is stored in a signal recording device 77 connected to the surface electrometer 76. The measured voltage V2 recorded in the signal recording device 77 is transmitted to the control unit 2.

[0041] The control unit 2 calculates the self-bias voltage Vdc based on the potential (voltage V2) measured by the surface electrometer 76 using the probe 75. Let C1 be the capacitance between the electrostatic chuck electrode 1111b and the substrate W, C2 be the capacitance between the copper disk 72 and the copper plate 73 (ground), C3 be the capacitance of the filter 71, and V2 be the voltage between the copper disk 72 and the copper plate 73 measured by the surface electrometer 76 using the probe 75. The self-bias voltage Vdc is expressed by the following equation (1). The capacitances C1, C2, and C3 are fixed values ​​determined by design parameters: Vdc=V2×(C2+C3) / C1+V2 (1)

[0042] In addition, the control unit 2 may be configured to calculate the self-bias voltage Vdc as the potential difference between the potential (average value of the potential in the section not affected by noise) measured by the surface electrometer 76 using the probe 75 before generating plasma in the plasma processing chamber 10 (before supplying the source RF signal) and the potential (average value of the potential in the section not affected by noise) measured by the surface electrometer 76 using the probe 75 while generating plasma (while supplying the source RF signal).

[0043] [Control Method] Next, a control method for detecting the plasma state and adjusting recipe parameters to achieve a suitable plasma state will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of a control method for a plasma processing system. Here, the plasma electron temperature T ｅ and the plasma electron density n ｅ This section explains how to measure this.

[0044] First, the control unit 2 controls the transport device (not shown) to place the substrate W on the substrate support unit 11. Next, the control unit 2 sets the switch 81a of the relay box 81 to the connected state to supply a chucking voltage from the chuck power supply 80 to the electrostatic chuck electrode 1111b. As a result, the substrate W is attracted to and held by the electrostatic chuck 1111.

[0045] Next, the control unit 2 controls the gas supply unit 20 to supply the processing gas from the gas supply unit 20 to the plasma processing space 10s. The control unit 2 also controls the plasma generation unit 12 to generate plasma of the processing gas in the plasma processing space 10s.

[0046] In step S101, the control unit 2 acquires the set value of the heater power to be applied from the heater power supply 60 to the heater electrode 1111c.

[0047] Here, the control unit 2 detects the heat input from the plasma in each divided region Z. When the heat input from the plasma in each divided region Z increases, the control unit 2 determines the heater power setting value so as to reduce the duty ratio Duty of the power (voltage) applied from the heater power supply 60 to the heater electrode 1111c. Furthermore, when the heat input from the plasma in each divided region Z decreases, the control unit 2 determines the heater power setting value so as to increase the duty ratio Duty of the power (voltage) applied from the heater power supply 60 to the heater electrode 1111c. For example, the control unit 2 measures the temperature for each divided region Z of the electrostatic chuck 1111 and determines the heater power setting value so as to achieve a desired temperature. Note that the temperature for each divided region Z of the electrostatic chuck 1111 may be detected by a temperature sensor (not shown) provided inside the electrostatic chuck 1111 or may be determined from the resistance value of the heater electrode 1111c. The heater power supply 60 controls the heater power supplied to the heater electrode 1111c based on the set value of the heater power.

[0048] Here, the set value of the heater power is the peak voltage Vpp [V] of the AC power, the duty ratio Duty, and the electrical resistance value R of the heater electrode 1111c. ｈThe heater electrode 1111c is provided for each of the plurality of divided regions Z. Therefore, the control unit 2 obtains the heater power setting value for each divided region Z.

[0049] In step S102, the control unit 2 calculates the ion flow velocity Qi based on the acquired heater power setting value.

[0050] First, the control unit 2 calculates the time-average power P ａｖｅ Here, for each divided region Z, the time average power P is calculated based on the following equation (2): ａｖｅ Then, the time-averaged power P for each divided region Z is calculated. ａｖｅ is the heat flux Q [W / m ２ ]. P ａｖｅ (=Q)=(Vpp ２ / Rh)×Duty...(2)

[0051] The duty ratio Duty is the time (ON time) T during which AC power is applied to the heater electrode 1111c. ｏｎ and the time when it is not applied (off time) T ｏｆｆ is expressed by the following equation (3): Duty=T ｏｎ / (T ｏｎ +T ｏｆｆ ) ... (3)

[0052] Here, in the plasma processing, when the plasma processing conditions such as the type of processing gas used, pressure, and temperature are substantially the same, the heat flux Q from the heater electrode 1111c to the substrate W can be regarded as the ion flow rate Qi from the plasma to the substrate W. Therefore, the relationship of equation (4) is obtained. P ａｖｅ (=Q)=Qi...(4)

[0053] In this way, the control unit 2 calculates the ion flow velocity Qi for each divided region Z based on the set value of the heater power for each divided region Z.

[0054] In step S103, the control unit 2 measures the self-bias voltage Vdc [V] applied to the substrate W using the surface potential measuring device 70. Here, during plasma generation (during substrate processing using plasma), the control unit 2 sets the switch 81a of the relay box 81 to an open state, putting the electrostatic chuck electrode 1111b in a floating state, and measures the voltage V2 of the surface potential measuring device 70. Then, the control unit 2 calculates the self-bias voltage Vdc [V] based on the voltage V2 and equation (1).

[0055] In step S104, the control unit 2 calculates the plasma electron temperature T ｅ Calculate [K].

[0056] Here, the electron temperature T is calculated from the measured self-bias voltage Vdc using the Maxwell distribution relational expression of the following equation (5): ｅ [K] is calculated. In addition, since the ion energy is proportional to the product of the self-bias voltage Vdc and the ion charge, the total ion energy incident on the substrate W can also be calculated from equation (5). ｅ is the mass of the electron [kg], ν ｅ is the electron velocity [m / s], e is the electron charge [C], k ｂ represents the Boltzmann constant. Vdc = m ｅ ×ν ｅ ２ / 2e=8k ｂ ×T ｅ / eπ ... (5)

[0057] In step S105, the control unit 2 calculates the ion flow velocity Qi and the electron temperature T ｅ Based on this, the electron density of the plasma n ｅ Calculate.

[0058] Here, the ion flow velocity Qi calculated in step S102 and the electron temperature T calculated in step S104 are ｅ Based on this, the electron density n ｅ where Ji is the ion saturation current [A], S is the area of ​​the substrate W [m ２ ], Vp is the plasma potential [V], m ｉrepresents the mass of the ions [kg]. When the plasma processing conditions, such as the type of processing gas used, pressure, and temperature, are almost the same, the plasma potential Vp can be considered to be almost the same. Therefore, a preset value can be used as the plasma potential Vp. Qi = Ji × S × (Vp - Vdc) (6) Ji = 0.6e × n ｅ × (k ｂ ×T ｅ / m ｉ ) ０．５ ... (7)

[0059] As described above, the control unit 2 can calculate the electron temperature T with a simple configuration based on the voltage V2 measured by the surface potential measuring device 70 and the set value of the heater power applied to the heater electrode 1111c. ｅ and electron density n ｅ In other words, the plasma state can be calculated with a simple configuration, and the plasma state can be grasped. For example, the plasma state can be measured with a simple configuration without using a substrate-type temperature sensor that detects the heat flux to the substrate W, a Langmuir probe that detects the plasma density, or the like.

[0060] In addition, one heater electrode 1111c is embedded in each divided region Z. Therefore, the ion flow velocity Qi is calculated for each divided region Z, and the electron density n ｅ Therefore, the state of plasma can be calculated for each divided region Z, and the plasma distribution over the entire substrate W can be estimated.

[0061] In step S106, the control unit 2 calculates the calculated electron temperature T ｅ and electron density n ｅ Here, the control unit 2 adjusts the recipe parameters to suitable values ​​based on the plasma state. The control unit 2 also adjusts the recipe parameters to suitable values ​​based on the estimated plasma distribution.

[0062] 6 is an example of a graph showing the tendency of the plasma state with respect to recipe parameters. In this example, the power of the source RF signal (HF Power) will be used as an example of the recipe parameter. Also, the heat flux and ion energy will be used as examples of parameters indicating the plasma state. Note that the ion energy is related to the electron temperature T ｅ The heat flux is proportional to the electron temperature T ｅ and electron density n ｅ is proportional to.

[0063] The horizontal axis represents the power (HF power) of the source RF signal. The first vertical axis represents the heat flux, and the second vertical axis represents the ion energy. Reference numeral 601 represents the heat flux. Reference numeral 602 represents the ion energy.

[0064] In the example of Fig. 6, plasma is generated by changing the power (HF Power) of the source RF signal as an example of a recipe parameter, and the heat flux and ion energy at each power are detected by the processes shown in steps S101 to S105 of Fig. 5. In this example, increasing the power of the source RF signal shows a tendency for the heat flux to increase, and a tendency for the change in ion energy to be suppressed.

[0065] Similarly, plasma is generated while changing other recipe parameters (for example, the power of the bias RF signal), and the heat flux and ion energy for each recipe parameter are detected by the processes shown in steps S101 to S105 of FIG.

[0066] In this way, the tendency of the parameters indicating the plasma state when each recipe parameter is changed is detected and stored as a database in the memory unit 2a2 of the control unit 2. Based on the stored database, the control unit 2 adjusts the recipe parameters to suitable values ​​to achieve the desired plasma state.

[0067] Furthermore, the plasma state (electron temperature T ｅ and electron density nｅ By detecting the change in the temperature, it is possible to detect a change in the state (condition) of the plasma processing apparatus 1 (for example, the wear state of consumable parts in the plasma processing chamber 10, etc.).

[0068] 5, the recipe parameters can be adjusted depending on the wear state of consumable parts in the plasma processing chamber 10. This allows the operating time of the plasma processing apparatus 1 to be extended, and the maintenance interval to be extended. Furthermore, maintenance can be performed at an appropriate timing.

[0069] Although the description has been given of calculating the state of plasma using the self-bias voltage detected by the surface potential measurement device 70 connected to the electrostatic chuck electrode 1111b provided in the central region 111a of the electrostatic chuck 1111 and the set value of the heater power of the heater electrode 1111c, this is not limiting. For example, the state of plasma may be calculated using the self-bias voltage detected by the surface potential measurement device 70 connected to an annular electrostatic chuck electrode (not shown) for attracting an edge ring provided in the annular region 111b of the electrostatic chuck 1111 and the set value of the heater power of a heater electrode (not shown) for heating the edge ring. Alternatively, the state of plasma may be calculated using the self-bias voltage detected by the surface potential measurement device 70 connected to the electrostatic chuck electrode 1111b and the set value of the heater power of a heater electrode (not shown) for heating the edge ring.

[0070] The above describes embodiments of the plasma processing system, but the present disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure as described in the claims.

[0071] The embodiments disclosed above include, for example, the following: (Supplementary Note 1) A plasma processing apparatus comprising: a plasma processing chamber; a base disposed within the plasma processing chamber; an electrostatic chuck disposed on top of the base and including a plurality of divided regions; an attraction electrode disposed within the electrostatic chuck; heater electrodes disposed below the attraction electrode for each of the plurality of divided regions; a heater power supply electrically connected to the heater electrode; a surface potential measuring device electrically connected to the attraction electrode and having a surface electrometer; and a controller, wherein the controller calculates a state of plasma from a set value of power applied from the heater power supply to the heater electrode and a potential measured by the surface electrometer. (Supplementary Note 2) The plasma processing apparatus according to Supplementary Note 1, wherein the set value of power includes a peak voltage and a duty ratio of AC power supplied to the heater electrode by the heater power supply, and an electrical resistance value of the heater electrode. (Supplementary Note 3) The plasma processing apparatus according to Supplementary Note 1 or Supplementary Note 2, wherein the calculated state of plasma includes an electron temperature and / or an electron density of plasma. (Supplementary Note 4) The plasma processing apparatus according to Supplementary Note 3, wherein the control unit is configured to execute the following steps: acquiring a set value of power to be applied to the heater electrode from the heater power supply; calculating an ion flow rate based on the acquired set value of power; calculating a self-bias voltage based on a potential measured by the surface electrometer; calculating the electron temperature of the plasma based on the calculated self-bias voltage; and calculating the electron density of the plasma based on the calculated ion flow rate and the calculated electron temperature. (Supplementary Note 5) The plasma processing apparatus according to any of Supplementary Notes 1 to 4, wherein the control unit adjusts recipe parameters based on the calculated state of the plasma. (Supplementary Note 6) The plasma processing apparatus according to any of Supplementary Notes 1 to 5, wherein the control unit detects a wear state of a consumable part in the plasma processing chamber based on the calculated state of the plasma.(Supplementary Note 7) The plasma processing apparatus according to any one of Supplementary Note 1 to Supplementary Note 6, wherein the surface potential measuring device comprises: a member having a capacitance electrically connected to the chucking electrode; and the surface electrometer measuring a value corresponding to an amount of charge accumulated in the member having a capacitance. (Supplementary Note 8) The plasma processing apparatus according to Supplementary Note 7, further comprising: an chucking power supply; and a switching unit switching an electrical connection between the chucking electrode and the chucking power supply, wherein the surface electrometer measures the value corresponding to the amount of charge accumulated in the member having a capacitance in a state where the electrical connection between the chucking electrode and the chucking power supply is interrupted. (Supplementary Note 9) A method for controlling a plasma processing apparatus comprising: a plasma processing chamber; a base disposed within the plasma processing chamber; an electrostatic chuck disposed on top of the base and including a plurality of divided regions; an attraction electrode disposed within the electrostatic chuck; heater electrodes disposed below the attraction electrode for each of the plurality of divided regions; a heater power supply electrically connected to the heater electrode; and a surface potential measuring device electrically connected to the attraction electrode and having a surface electrometer, the method comprising: calculating a plasma state from a set value of power applied to the heater electrode from the heater power supply and a potential measured by the surface electrometer. (Supplementary Note 10) The control method according to Supplementary Note 9, wherein the set value of power includes a peak voltage and a duty ratio of AC power supplied to the heater electrode by the heater power supply, and an electrical resistance value of the heater electrode. (Supplementary Note 11) The control method according to Supplementary Note 9 or Supplementary Note 10, wherein the calculated plasma state includes a plasma electron temperature and / or a plasma electron density. (Supplementary Note 12) The control method according to Supplementary Note 11, comprising the steps of: acquiring a set value of power to be applied to the heater electrode from the heater power supply; calculating an ion flow velocity based on the acquired set value of power; calculating a self-bias voltage based on a potential measured by the surface electrometer; calculating the electron temperature of the plasma based on the calculated self-bias voltage; and calculating the electron density of the plasma based on the calculated ion flow velocity and the calculated electron temperature.(Supplementary Note 13) The control method according to any one of Supplementary Notes 9 to 12, further comprising: adjusting a recipe parameter based on the calculated plasma state. (Supplementary Note 14) The control method according to any one of Supplementary Notes 9 to 13, further comprising: detecting a wear state of a consumable part in the plasma processing chamber based on the calculated plasma state.

[0072] This application claims priority to U.S. patent application Ser. No. 63 / 673,274, filed July 19, 2024, the entire contents of which are incorporated herein by reference.

[0073] REFERENCE SIGNS LIST 1 Plasma processing apparatus 2 Control unit 10 Plasma processing chamber 11 Substrate support unit 60 Heater power supply 70 Surface potential measuring device 71 Filter 72 Copper disc 73 Copper plate 74 Acrylic plate 75 Probe 76 Surface potential meter 77 Signal recording device 78 Potential measurement system 80 Chuck power supply 81 Relay box (switching unit) 81a Switch 111 Main body 1110 Base 1111 Electrostatic chuck 1111a Ceramic member 1111b Electrostatic chuck electrode (attraction electrode) 1111c Heater electrode W Substrate Z Divided area

Claims

1. A plasma processing apparatus comprising: a plasma processing chamber; a base disposed within the plasma processing chamber; an electrostatic chuck disposed on top of the base and including a plurality of divided regions; an attraction electrode disposed within the electrostatic chuck; heater electrodes disposed below the attraction electrode for each of the plurality of divided regions; a heater power supply electrically connected to the heater electrode; a surface potential measuring device electrically connected to the attraction electrode and having a surface potential meter; and a control unit, wherein the control unit calculates a state of plasma from a set value of power applied from the heater power supply to the heater electrode and a potential measured by the surface potential meter.

2. The plasma processing apparatus according to claim 1, wherein the power setting value includes a peak voltage and a duty ratio of the AC power supplied from the heater power supply to the heater electrode, and an electrical resistance value of the heater electrode.

3. The plasma processing apparatus according to claim 1, wherein the calculated state of the plasma includes the plasma electron temperature and / or the plasma electron density.

4. The plasma processing apparatus of claim 3, wherein the control unit is configured to be able to execute the following steps: acquiring a set value of the power to be applied to the heater electrode from the heater power supply; calculating an ion flow velocity based on the acquired set value of the power; calculating a self-bias voltage based on the potential measured by the surface potential meter; calculating the electron temperature of the plasma based on the calculated self-bias voltage; and calculating the electron density of the plasma based on the calculated ion flow velocity and the calculated electron temperature.

5. The plasma processing apparatus according to claim 1, wherein the control unit adjusts recipe parameters based on the calculated state of the plasma.

6. The plasma processing apparatus according to claim 1, wherein the control unit detects a wear state of consumable parts in the plasma processing chamber based on the calculated state of the plasma.

7. The plasma processing apparatus according to claim 1, wherein the surface potential measuring device comprises: a member having a capacitance electrically connected to the chucking electrode; and the surface potential meter for measuring a value corresponding to the amount of charge accumulated in the member having a capacitance.

8. The plasma processing apparatus according to claim 7, further comprising: an adsorption power supply; and a switching unit that switches the electrical connection between the adsorption electrode and the adsorption power supply; wherein the surface potential measuring device measures a value corresponding to the amount of charge accumulated in the member having electrostatic capacity when the electrical connection between the adsorption electrode and the adsorption power supply is cut off.

9. A method for controlling a plasma processing apparatus comprising: a plasma processing chamber; a base disposed within the plasma processing chamber; an electrostatic chuck disposed on top of the base and including a plurality of divided regions; an attraction electrode disposed within the electrostatic chuck; heater electrodes disposed below the attraction electrode for each of the plurality of divided regions; a heater power supply electrically connected to the heater electrode; and a surface potential measuring device electrically connected to the attraction electrode and having a surface potential meter, wherein the method calculates a state of plasma from a set value of power applied to the heater electrode from the heater power supply and a potential measured by the surface potential meter.

10. The control method according to claim 9, wherein the power setting value includes a peak voltage and a duty ratio of the AC power supplied from the heater power supply to the heater electrode, and an electrical resistance value of the heater electrode.

11. The control method according to claim 9, wherein the calculated state of the plasma includes the plasma electron temperature and / or the plasma electron density.

12. The control method according to claim 11, comprising the steps of: acquiring a set value of the power to be applied to the heater electrode from the heater power supply; calculating an ion flow velocity based on the acquired set value of the power; calculating a self-bias voltage based on the potential measured by the surface electrometer; calculating the electron temperature of the plasma based on the calculated self-bias voltage; and calculating the electron density of the plasma based on the calculated ion flow velocity and the calculated electron temperature.

13. The control method according to claim 9, further comprising adjusting a recipe parameter based on the calculated plasma state.

14. The control method according to claim 9, further comprising detecting a wear state of a consumable part in the plasma processing chamber based on the calculated plasma state.

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