Plasma processing apparatus and method for controlling plasma processing apparatus

Abstract

Provided are a plasma processing apparatus that suppresses a change in plasma density resulting from consumption of a component, and a method for controlling the plasma processing apparatus.　A plasma processing apparatus comprising: a plasma processing chamber; a substrate support part that is provided within the plasma processing chamber and supports a substrate; a gas introduction part that introduces at least one processing gas into the plasma processing chamber; a power supply that supplies a high-frequency signal to an electrode; an edge ring; a bias power supply that supplies a bias signal to the edge ring; and a control unit, the plasma processing apparatus implementing plasma processing on the substrate, wherein the control unit implements plasma processing on one substrate by using the plasma processing apparatus, measures an electric element during the plasma processing, and, when implementing plasma processing on another substrate by using the plasma processing apparatus after the plasma processing implemented on the one substrate, controls the high-frequency power of the high-frequency signal on the basis of the measured electric element.

Description

Plasma Processing Apparatus and Control Method of Plasma Processing Apparatus

[0001] The present disclosure relates to a plasma processing apparatus and a control method of the plasma processing apparatus.

[0002] In Patent Document 1, there is disclosed a plasma processing apparatus including a plasma processing chamber, a substrate support portion provided in the plasma processing chamber for supporting a substrate, a gas introduction portion for introducing at least one processing gas into the plasma processing chamber, a power source for supplying a high-frequency signal to an electrode, and a control unit, the control unit performing plasma processing on one substrate with the plasma processing apparatus, measuring electrical elements during the plasma processing, and controlling the high-frequency power of the high-frequency signal based on the measured electrical elements when performing plasma processing on another substrate with the plasma processing apparatus after the plasma processing of the one substrate.

[0003] Japanese Patent Application Laid-Open No. 2024-53875

[0004] On one aspect, the present disclosure provides a plasma processing apparatus and a control method of the plasma processing apparatus that suppress a change in plasma density due to wear of components.

[0005] To solve the above problems, according to one aspect, there is provided a plasma processing apparatus including a plasma processing chamber, a substrate support portion provided in the plasma processing chamber for supporting a substrate, a gas introduction portion for introducing at least one processing gas into the plasma processing chamber, a power source for supplying a high-frequency signal to an electrode, an edge ring surrounding the substrate supported by the substrate support portion, a bias power source for supplying a bias signal to the edge ring, and a control unit, the control unit performing plasma processing on one substrate with the plasma processing apparatus, measuring electrical elements during the plasma processing, and controlling the high-frequency power of the high-frequency signal based on the measured electrical elements when performing plasma processing on another substrate with the plasma processing apparatus after the plasma processing of the one substrate.

[0006] In one aspect, it is possible to provide a plasma processing apparatus and a control method for the plasma processing apparatus that suppress changes in plasma density due to component wear.

[0007] An example of a diagram illustrating an example configuration of a plasma processing system. An example of a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus. An example of a diagram illustrating an example configuration for detecting electrical elements related to plasma density in a plasma processing system. An example of a graph showing the peak-to-peak voltage of a source RF signal in a plasma processing apparatus. An example of a graph showing the RF power and peak-to-peak voltage of a source RF signal. An example of a graph showing the RF power and peak-to-peak voltage of a source RF signal. An example of a graph showing the RF power and peak-to-peak voltage of a source RF signal in a plasma processing apparatus. An example of a schematic diagram illustrating the control concept of a plasma processing apparatus of one embodiment. An example of a flowchart illustrating the control of a plasma processing apparatus of one embodiment. An example of a graph showing the peak-to-peak voltage of a source RF signal. An example of a graph showing the peak-to-peak voltage of a source RF signal. An example of a graph showing the change in the peak-to-peak voltage of a source RF signal. An example of a schematic cross-sectional diagram showing the positions of the substrate support and the upper end of the sheath. An example of a schematic cross-sectional diagram showing the positions of the substrate support and the upper end of the sheath. Another example of a schematic cross-sectional diagram showing the positions of the substrate support and the upper end of the sheath.

[0008] The following describes embodiments for implementing this disclosure with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0009] [Plasma Processing System] Figure 1 is an example of a diagram illustrating an example of the 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 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 outlet for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20, which will be described later, and the gas outlet is connected to an exhaust system 40, which will be described later. The substrate support unit 11 is located in the plasma processing space and has a substrate support surface for supporting a substrate.

[0010] The plasma generation 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), ECR (Electron Cyclotron Resonance) plasma, helicon wave excited plasma (HWP), or surface wave plasma (SWP), etc. Various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC (Direct Current) plasma generation units, may also be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes an RF (Radio Frequency) signal and a microwave signal. 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 processes described herein. The control unit 2 may be configured to control the elements of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 is implemented, for example, by a computer 2a. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The functions realized by the processing unit 2a1 described herein may be implemented in a circuit or processing circuit, including a general-purpose processor, an application-specific processor, integrated circuits, ASICs (Application Specific Integrated Circuits), a CPU (Central Processing Unit), a conventional circuit, and / or a combination thereof, programmed to realize the described functions. The processor is considered to be a circuit or processing circuit, including transistors and other circuits. The processor may be a programmed processor that executes a program stored in the storage unit 2a2. This program may be pre-stored in the storage unit 2a2 or retrieved via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The storage unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), 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).In this disclosure, circuits, units, and means are hardware programmed to perform or configured to perform the functions described. Such hardware may be any hardware described in this disclosure, or any hardware known to be programmed to perform or execute the functions described. If such hardware is a processor that is considered to be a type of circuit, such circuit, means, or unit is a combination of hardware and software used to constitute such hardware and / or processor.

[0012] [Plasma Processing Equipment] Below, an example of the configuration of a capacitively coupled plasma processing equipment as an example of plasma processing equipment 1 will be described. Figure 2 is an example of a diagram illustrating the configuration of a capacitively coupled plasma processing equipment (substrate processing equipment) 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 unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is located inside the plasma processing chamber 10. The shower head 13 is located above the substrate support unit 11. In one embodiment, the shower head 13 constitutes 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 shower head 13, the side walls 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0014] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting the 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 portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is placed on the central region 111a of the main body portion 111, and the ring assembly 112 is placed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also called the substrate support surface for supporting the substrate W, and the annular region 111b is also called the ring support surface for supporting the ring assembly 112.

[0015] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is placed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic chuck electrode 1111b placed within the ceramic member 1111a. The electrostatic chuck electrode 1111b is also called a clamping electrode. In one embodiment, the electrostatic chuck electrode 1111b is electrically connected or coupled to a chuck power supply. The chuck power supply may be a DC power supply or an AC power supply. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Furthermore, other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have an annular region 111b. In this case, the ring assembly 112 may be placed on the annular electrostatic chuck or the annular insulating member, or it may be placed on both the electrostatic chuck 1111 and the annular insulating member. In addition, at least one bias electrode, which is electrically connected or coupled to the power supply 31 and / or power supply 32 described later, may be placed inside the ceramic member 1111a. In this case, at least one bias electrode functions as a lower electrode. Also, the conductive member of the base 1110 and the bias electrode inside the ceramic member 1111a may function as multiple lower electrodes. In one embodiment, the first voltage generation unit 32a, which functions as a voltage pulse generation unit described later, is electrically connected or coupled to the bias electrode inside the ceramic member 1111a, and the first RF generation unit 31a, described later, is electrically connected or coupled to the conductive member of the base 1110. Furthermore, the electrostatic chuck electrode 1111b may function as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

[0016] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one covering ring. The edge ring (also called a focus ring) is an annular member that surrounds the outer circumference of the substrate W supported by the substrate support portion 11. The edge ring is formed of a conductive material or an insulating material, and the covering ring is formed of an insulating material.

[0017] The substrate support section 11 may also include a temperature control 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 control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are arranged within the ceramic member 1111a of the electrostatic chuck 1111. The substrate support section 11 may also include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0018] The showerhead 13 is configured to introduce at least one processing 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 a plurality of gas inlet ports 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 through the plurality of gas inlet ports 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0019] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas to the shower head 13 from a corresponding gas source 21 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one processing gas.

[0020] The power supply system 30 includes a power supply 31 that is electrically connected to or coupled to the plasma processing chamber 10. In one embodiment, the power supply 31 is electrically connected to 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 part of the plasma generation unit 12. In addition, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and ionic components in the formed plasma can be drawn into the substrate W.

[0021] The power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 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 generation unit 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 generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. One or more generated source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0022] The second RF generation unit 31b is electrically connected to or coupled to at least one lower electrode and is configured to generate a bias RF signal (bias RF power). In one embodiment, the second RF generation unit 31b is electrically connected to or coupled to at least one lower electrode via at least one impedance matcher. When the first RF generation unit 31a is electrically connected to or coupled to a lower electrode, the second RF generation unit 31b may be electrically connected to or coupled to the same lower electrode, or it may be electrically connected to or coupled to a different 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 generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

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

[0024] In various embodiments, the first and / or second voltage signals may be pulsed. In this case, the first voltage generation unit 32a and / or the second voltage generation unit 32b function as voltage pulse generation units 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 has a plurality of cycles, each cycle including a burst of voltage pulses in a first period and a constant reference voltage in a second period. That is, in the sequence of voltage pulses, the burst of voltage pulses is repeated. The absolute value of the voltage level of the voltage pulse is greater than the absolute value of the voltage level of the reference voltage. The voltage pulse may have an arbitrary waveform having a rectangle, trapezoid, triangle, or a combination thereof, and the arbitrary waveform may change over time. The voltage pulse may have positive polarity or negative polarity. The sequence of voltage pulses may also include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The first and second voltage generation units 32a and 32b may be provided in addition to the power supply 31, and the first voltage generation unit 32a may be provided in place of the second RF generation unit 31b.

[0025] Furthermore, the plasma processing apparatus 1 may include a power supply (bias power supply) 35 that is electrically connected to or coupled to the plasma processing chamber 10. The power supply 35 may be included in the power supply system 30. The power supply 35 includes a third voltage generation unit 35a. In one embodiment, the third voltage generation unit 35a is electrically connected to or coupled to at least one annular member (edge ​​ring) of the ring assembly 112 and is configured to generate a third voltage signal (bias signal). The generated third voltage signal is applied to at least one annular member (edge ​​ring) of the ring assembly 112.

[0026] For example, by applying plasma treatment to the substrate W, the upper surface of the annular member (edge ​​ring) of the ring assembly 112 is worn down, and the height of the upper surface of the annular member (edge ​​ring) decreases. This reduces the height of the sheath above the annular member (edge ​​ring). When the height of the sheath above the annular member (edge ​​ring) becomes lower than the height of the sheath above the central region of the substrate W, the sheath tilts near the outer periphery of the substrate W such that the inside is higher and the outside is lower. This may cause the angle of incidence of ions near the outer periphery of the substrate W to change inward. To address this, a DC voltage (third voltage signal) is supplied to the annular member (edge ​​ring) to adjust the thickness of the sheath near the outer periphery of the substrate W, thereby adjusting the angle of incidence of ions near the outer periphery of the substrate W.

[0027] Furthermore, in various embodiments, the third voltage signal may be pulsed. In this case, the third voltage generation unit 35a functions as a voltage pulse generation unit configured to generate a sequence of voltage pulses. Thus, the sequence of voltage pulses is applied to at least one annular member (edge ​​ring) of the ring assembly 112. In one embodiment, the sequence of voltage pulses has a plurality of cycles, each cycle including a burst of voltage pulses in a third period and a constant reference voltage in the third period. That is, in the sequence of voltage pulses, the burst of voltage pulses is repeated. The absolute value of the voltage level of the voltage pulse is greater than the absolute value of the voltage level of the reference voltage. The voltage pulse may be an arbitrary waveform having a rectangular, trapezoidal, triangular, or a combination thereof, and the arbitrary waveform may change over time. The voltage pulse may have positive polarity or negative polarity. Also, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one cycle. Note that the third voltage generation unit 35a may be provided in addition to the power supply 35.

[0028] The exhaust system 40 may be connected to, for example, a gas outlet 10e located 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 regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0029] Next, the configuration of a plasma processing system for detecting electrical elements related to the plasma density generated in the plasma processing space 10s will be explained using Figure 3. Figure 3 is an example of a diagram illustrating an example of a configuration for detecting electrical elements related to plasma density in a plasma processing system. In the configuration example shown in Figure 3, the plasma processing apparatus 1 will be described using a configuration in which a source RF signal (source RF power) is supplied from the first RF generation unit 31a to the upper electrode and a bias RF signal (bias RF power) is supplied from the second RF generation unit 31b to the lower electrode.

[0030] The first RF generation unit 31a is coupled to the upper electrode via an impedance matching circuit 33 and is configured to generate a source RF signal for plasma generation. The impedance matching circuit 33 matches the impedance between the power supply 31 (first RF generation unit 31a) and the plasma load, thereby improving the efficiency of supplying the source RF signal.

[0031] The second RF generation unit 31b is coupled to the lower electrode via an impedance matching circuit 34 and is configured to generate a bias RF signal. The impedance matching circuit 33 matches the impedance between the power supply 31 (second RF generation unit 31b) and the plasma load, thereby improving the supply efficiency of the bias RF signal.

[0032] The impedance matching circuit 33 is provided between the power supply 31 (first RF generation unit 31a) and the upper electrode, and has an input terminal connected to the power supply 31 (first RF generation unit 31a) and an output terminal connected to the upper electrode. The impedance matching circuit 33 is also provided with a detection circuit 33a. The detection circuit 33a detects at least one of the output terminal voltage, output terminal current, and output terminal power of the impedance matching circuit 33 and outputs a detection signal to the control unit 2.

[0033] The impedance matching circuit 34 is provided between the power supply 31 (second RF generation unit 31b) and the lower electrode, and has an input terminal connected to the power supply 31 (second RF generation unit 31b) and an output terminal connected to the lower electrode. The impedance matching circuit 34 is also provided with a detection circuit 34a. The detection circuit 34a detects at least one of the output terminal voltage, output terminal current, and output terminal power of the impedance matching circuit 34 and outputs a detection signal to the control unit 2.

[0034] The control unit 2 includes a measuring unit 210, a storage unit 220, and a power supply control unit 230.

[0035] The measurement unit 210 measures electrical elements related to plasma density based on the detection signals from the detection circuits 33a and 34a. Here, the electrical elements related to plasma density are those that correlate with plasma density and are measured (calculated) by the measurement unit 210 based on the detection signals measured by the detection circuits 33a, 34a, etc. Specifically, the electrical elements related to plasma density measured by the measurement unit 210 include the peak-to-peak voltage of the source RF signal (hereinafter also referred to as "HF Vpp"). The peak-to-peak voltage of the source RF signal (HF Vpp) is measured (calculated) by the measurement unit 210 based on the detection signal of the output terminal voltage of the impedance matching circuit 33 detected by the detection circuit 33a.

[0036] Furthermore, the electrical elements related to plasma density may include at least one of the following: the peak-to-peak voltage of the source RF signal (HF Vpp), the self-bias voltage (hereinafter also referred to as "Vdc"), the peak-to-peak voltage of the bias RF signal (hereinafter also referred to as "LF Vpp"). For example, if the bias RF signal is involved in plasma generation and correlates with plasma density depending on the frequency of the bias RF power, the electrical elements related to plasma density measured by the measurement unit 210 may include at least one of the following: the peak-to-peak voltage of the bias RF signal (LF Vpp), the peak-to-peak voltage of the source RF signal (HF Vpp), and the self-bias voltage (Vdc).

[0037] The peak-to-peak voltage (LF Vpp) of the bias RF signal is measured (calculated) by the measurement unit 210 based on the detection signal of the output terminal voltage of the impedance matching circuit 33 detected by the detection circuit 33a. The self-bias voltage (Vdc) is also measured (calculated) by the measurement unit 210 based on the detection signal of the output terminal voltage of the impedance matching circuit 33 detected by the detection circuit 33a. Furthermore, the peak-to-peak voltage (HF Vpp) of the source RF signal and the peak-to-peak voltage (LF Vpp) of the bias RF signal may both be measured (calculated) by a PI probe installed inside the chamber. In the following description, the electrical element related to plasma density will be described as the peak-to-peak voltage (HF Vpp) of the source RF signal.

[0038] The memory unit 220 stores electrical elements related to the plasma density measured by the measurement unit 210. Here, it stores the peak-to-peak voltage (HF Vpp) of the source RF signal when the substrate W is subjected to plasma processing. The memory unit 220 also stores information showing the correspondence (for example, a correlation table), which will be described later. The information showing the correspondence stores information showing the relationship between the amount of change in the electrical elements related to the plasma density and the amount of adjustment of the power supply 31. Specifically, the information showing the correspondence stores information showing the correspondence between the amount of increase in the peak-to-peak voltage (HF Vpp) of the source RF signal and the amount of increase in the RF power (hereinafter also referred to as "HF Power") of the power supply 31 (first RF generation unit 31a) required to realize that increase. This information showing the correspondence may be stored in a correlation table, as a function, or in other forms.

[0039] The power control unit 230 controls the power supply 31. Specifically, the power control unit 230 controls the RF power (HF Power) of the source RF signal by controlling the power supply 31.

[0040] Here, changes in the peak-to-peak voltage (HF Vpp) of the source RF signal in the plasma processing apparatus 1 will be described with reference to FIG. 4. FIG. 4 is an example of a graph showing the peak-to-peak voltage (HF Vpp) of the source RF signal in the plasma processing apparatus 1. In the graph shown in FIG. 4, the horizontal axis represents the number of operating days (Date) of the plasma processing apparatus 1, and the vertical axis represents the peak-to-peak voltage (HF Vpp) of the source RF signal.

[0041] Here, in the example shown in FIG. 4, the power control unit 230 controls the RF power (HF Power) of the source RF signal to be constant.

[0042] By operating the plasma processing apparatus 1 for a long period of time, parts (for example, the edge ring of the ring assembly 112, the cover ring, the electrostatic chuck 1111, etc.) in the plasma processing chamber 10 exposed to the plasma are consumed.

[0043] In the plasma processing apparatus 1, replacement of the consumed parts and cleaning of the inside of the plasma processing chamber 10 are performed. In the example shown in FIG. 4, the plasma processing apparatus 1 performs "Mini Clean", "Full Clean", and "Swap kit".

[0044] In "Mini Clean", for example, replacement of the first group of parts among the parts in the plasma processing chamber 10 is performed, and cleaning of the inside of the plasma processing chamber 10 is performed.

[0045] In "Full Clean", for example, replacement of the first group and the second group of parts among the parts in the plasma processing chamber 10 is performed, and cleaning of the inside of the plasma processing chamber 10 is performed. That is, "Full Clean" includes replacement of the parts replaced in "Mini Clean".

[0046] In the "Swap kit", for example, parts in the first group and the third group among the parts in the plasma processing chamber 10 are replaced, and cleaning in the plasma processing chamber 10 is performed. That is, the "Swap kit" includes replacement of parts replaced in the "Mini Clean". Also, in the "Swap kit", replacement of parts in the second group among the parts in the plasma processing chamber 10 may further be performed. That is, the "Swap kit" may also include replacement of parts replaced in the "Full Clean".

[0047] Also, the parts in the first group are, for example, parts that are more likely to be consumed than the parts in the second group and the third group, and parts with a shorter replacement interval than the parts in the second group. The parts in the first group may be, for example, the edge ring of the ring assembly 112, the cover ring, etc.

[0048] The parts in the second group are, for example, parts that are more likely to be consumed than the parts in the third group, and parts with a shorter replacement interval than the parts in the third group. The parts in the second group may be, for example, the electrostatic chuck 1111, the Outer-CEL (not shown) disposed on the outer peripheral side of the upper electrode (CEL), etc.

[0049] The parts in the third group are parts with a longer replacement interval than the parts in the first group and the second group. The parts in the third group may be, for example, the dielectric part (Ins-B, not shown) at the outer edge of the electrostatic chuck 1111, the silicon-containing member (Si-GRD, not shown) at the outer edge of the upper electrode, etc.

[0050] As shown in Figure 4, as the operating time of the plasma processing apparatus 1 increases, the parts in the plasma processing chamber 10 wear out, causing the peak-to-peak voltage (HF Vpp) of the source RF signal to decrease. Furthermore, the decrease in the peak-to-peak voltage (HF Vpp) of the source RF signal reduces the plasma density of the plasma generated in the plasma processing space 10s. Then, by replacing the worn parts and cleaning the inside of the plasma processing chamber 10 as shown in "Mini Clean," "Full Clean," and "Swap kit," the peak-to-peak voltage (HF Vpp) of the source RF signal recovers, and the plasma density of the plasma generated in the plasma processing space 10s also recovers.

[0051] Thus, in a plasma processing apparatus 1 that controls the RF power (HF Power) of the source RF signal while keeping it constant, the peak-to-peak voltage (HF Vpp) of the source RF signal fluctuates by repeatedly decreasing and recovering. In addition, the plasma density of the plasma generated in the plasma processing space 10s also fluctuates by repeatedly decreasing and recovering. As a result, there is a risk that the characteristics of the product (e.g., semiconductor device) formed on the substrate W by plasma processing may change.

[0052] Figures 5A and 5B are examples of graphs showing the RF power (HF Power) and peak-to-peak voltage (HF Vpp) of the source RF signal. In the graphs shown in Figures 5A and 5B, the horizontal axis represents the RF application time since the part was replaced (Parts RFH). On the vertical axis, the RF power (HF Power) of the source RF signal is shown by a dashed line, and the peak-to-peak voltage (HF Vpp) of the source RF signal is shown by a solid line.

[0053] As shown in Figure 5A, when the RF power (HF Power) of the source RF signal, shown by the dashed line, is controlled to a constant value, the peak-to-peak voltage (HF Vpp) of the source RF signal, shown by the solid line, decreases over time due to wear and tear of parts. In other words, the plasma density of the plasma generated in the plasma processing space 10s decreases over time due to the application of RF.

[0054] In contrast, as shown in Figure 5B, if the RF power (HF Power) of the source RF signal, indicated by the dashed line, is controlled to increase with the passage of RF application time, fluctuations in the peak-to-peak voltage (HF Vpp) of the source RF signal, indicated by the solid line, can be suppressed. That is, fluctuations in the plasma density of the plasma generated in the plasma processing space 10s can be suppressed.

[0055] Further explanation will be given using Figure 6. Figure 6 is an example of a graph showing the RF power (HF Power) and peak-to-peak voltage (HF Vpp) of the source RF signal in the plasma processing apparatus 1. In the graph shown in Figure 6, the horizontal axis shows the RF application time (Parts RFH) since the replacement of parts. In the upper part of Figure 6, period 501 shows the interval of "Mini Clean". That is, the length of period 501 shows the usage period until the first group of parts is replaced. Period 502 shows the interval of "Full Clean". That is, the length of period 502 shows the usage period until the second group of parts is replaced. Period 503 shows the interval of "Swap kit". That is, the length of period 503 shows the usage period until the third group of parts is replaced. In the middle part of Figure 6, the RF power (HF Power) 510 of the source RF signal is shown. In the lower part of Figure 6, the peak-to-peak voltage (HF Vpp) 520 of the source RF signal is shown.

[0056] In the example shown in Figure 4, the power control unit 230 controls the RF power (HF Power) 510 of the source RF signal to increase from its initial value as the RF application time elapses, according to a predetermined recipe, within the interval of "Mini Clean" indicated by period 501. When a part is replaced, the RF power (HF Power) 510 of the source RF signal is returned to its initial value and controlled to increase from its initial value as the RF application time elapses, and this process is repeated.

[0057] This allows for the suppression of fluctuations in the peak-to-peak voltage (HF Vpp) 520 of the source RF signal by controlling the RF power (HF Power) 510 of the source RF signal to increase during each interval shown in period 501.

[0058] However, as shown in Figure 6, as the RF application time elapses by repeating period 501 multiple times, the peak-to-peak voltage (HF Vpp) 520 of the source RF signal decreases from its initial value. That is, the plasma density of the plasma generated in the plasma processing space 10s decreases. Therefore, over periods longer than period 501, the peak-to-peak voltage (HF Vpp) 520 of the source RF signal fluctuates, and the plasma density of the plasma generated in the plasma processing space 10s fluctuates.

[0059] <Control of Plasma Processing Apparatus 1 in One Embodiment> Next, the control of the plasma processing apparatus 1 in one embodiment will be explained using Figures 7 and 8. Figure 7 is an example of a schematic diagram illustrating the concept of control of the plasma processing apparatus 1 in one embodiment. Figure 8 is an example of a flowchart illustrating the control of the plasma processing apparatus 1 in one embodiment.

[0060] First, as shown by reference numeral 610, the plasma processing apparatus 1 undergoes a parts change (PM Parts Change). Here, for example, at least one part from the parts of the first to third groups is replaced. The plasma processing apparatus 1 may also be cleaned.

[0061] In step S100, the control unit 2 controls the power supply 35 (third voltage generation unit 35a) as a sheath controller to control the vertical position of the upper end of the sheath above the edge ring.

[0062] Here, the plasma processing apparatus 1 has a sheath controller. The sheath controller controls the vertical position of the upper end of the sheath above the edge ring. In the plasma processing apparatus 1 shown in Figure 1, the sheath controller has a power supply 35 that applies voltage to the edge ring. The sheath controller will be described later with reference to Figures 11A to 12B.

[0063] Next, in step S101, the control unit 2 performs plasma treatment on the target substrate and measures the electrical elements related to the plasma density during this process. Here, the peak-to-peak voltage (HF Vpp) of the source RF signal is measured as an electrical element related to the plasma density.

[0064] Here, as shown by reference numeral 620, the control unit 2 controls the plasma processing apparatus 1 to perform plasma processing on the target substrate (Target Wafer) according to the same recipe as for the manufacturing substrate described later. The RF power (HF Power) of the source RF signal uses the basic value (initial value) stored in the recipe. Here, the target substrate is a dummy wafer, and the plasma processing may be seasoning using a dummy wafer. Also, as shown by reference numeral 621, when performing plasma processing on the target substrate, the measurement unit 210 measures the peak-to-peak voltage (HF Vpp) of the source RF signal. The measurement unit 210 measures the peak-to-peak voltage (HF Vpp) of the source RF signal based on the detection signal of the detection circuit 33a. The measured peak-to-peak voltage (HF Vpp) of the source RF signal is then stored in the storage unit 220.

[0065] Next, in step S102, the control unit 2 adjusts the RF power of the RF signal based on the electrical elements related to the plasma density measured in step S101. Here, the control unit 2 adjusts the RF power (HF Power) of the source RF signal based on the peak-to-peak voltage (HF Vpp) of the source RF signal measured in step S101.

[0066] In the plasma processing, a target value for the peak-to-peak voltage (HF Vpp) of the source RF signal is predetermined. Based on the peak-to-peak voltage (HF Vpp) of the source RF signal measured in step S101, the control unit 2 adjusts the RF power (HF Power) of the source RF signal so that the peak-to-peak voltage (HF Vpp) of the source RF signal becomes the target value. Specifically, the power supply control unit 230 calculates the increase in the peak-to-peak voltage (HF Vpp) of the source RF signal from the difference between the peak-to-peak voltage (HF Vpp) of the source RF signal measured in step S101 and the target value. The storage unit 220 also stores information (for example, a correlation table) showing the correspondence between the increase in the peak-to-peak voltage (HF Vpp) of the source RF signal and the increase in the RF power (HF Power) of the source RF signal required to achieve that increase. The power control unit 230 calculates the increase in RF power (HF Power) of the source RF signal (offset amount) from information indicating the increase in peak-to-peak voltage (HF Vpp) of the source RF signal and its corresponding relationship. Then, the power control unit 230 corrects the RF power (HF Power) of the source RF signal (HF Power) by the calculated offset amount to the base value (initial value) stored in the recipe.

[0067] As shown in reference numeral 622, the control unit 2 adjusts the RF power (HF Power) of the source RF signal (HF Power Offset).

[0068] Next, in step S103, the control unit 2 performs plasma treatment on the manufacturing substrate and measures the electrical elements related to the plasma density during this process. Here, the peak-to-peak voltage (HF Vpp) of the source RF signal is measured as an electrical element related to the plasma density.

[0069] Here, as shown by reference numeral 630, the control unit 2 controls the plasma processing apparatus 1 to perform plasma processing on one lot of production substrates. In the plasma processing of the production substrates, as shown by reference numeral 622, the RF power (HF Power) of the source RF signal adjusted in step S102 is used. Also, as shown by reference numeral 631, when performing plasma processing on the production substrates, the measurement unit 210 measures the peak-to-peak voltage (HF Vpp) of the source RF signal. The measurement unit 210 measures the peak-to-peak voltage (HF Vpp) of the source RF signal based on the detection signal of the detection circuit 33a. The measured peak-to-peak voltage (HF Vpp) of the source RF signal is then stored in the storage unit 220.

[0070] Next, in step S104, the control unit 2 determines whether a predetermined number of processing steps has elapsed. The predetermined number of processing steps may be, for example, the number of substrates per lot, or for example, the number of substrates housed in a FOUP (Front Opening Unified Pod). If the predetermined number of processing steps has not elapsed (S104, NO), the control unit 2 returns to step S103. If the predetermined number of processing steps has elapsed (S104, YES), the control unit 2 proceeds to step S105.

[0071] Next, in step S105, the control unit 2 adjusts the RF power of the RF signal based on the electrical elements related to the plasma density measured in step S103. Here, the control unit 2 adjusts the RF power (HF Power) of the source RF signal based on the peak-to-peak voltage (HF Vpp) of the source RF signal measured in step S103.

[0072] Here, by repeating step S103, a predetermined number of manufacturing substrates (e.g., one lot) are plasma-treated, and the peak-to-peak voltages (HF Vpp) of multiple (determined number of) source RF signals are stored in the memory unit 220. Based on the peak-to-peak voltages (HF Vpp) of the multiple source RF signals measured in step S103, the control unit 2 adjusts the RF power (HF Power) of the source RF signal so that the peak-to-peak voltage (HF Vpp) of the source RF signal becomes the target value. Specifically, the power control unit 230 calculates the average value from the peak-to-peak voltages (HF Vpp) of the multiple source RF signals, and calculates the increase in the peak-to-peak voltage (HF Vpp) of the source RF signal from the difference between the average value and the target value. The power control unit 230 also calculates the increase in the RF power (HF Power) of the source RF signal (offset amount) from information (e.g., a correlation table) showing the increase in the peak-to-peak voltage (HF Vpp) of the source RF signal and its corresponding relationship. Then, the power control unit 230 corrects the RF power (HF Power) of the source RF signal by the offset amount calculated in step S105, using the current RF power of the source RF signal (in this example, the RF power including the base value (initial value) stored in the recipe plus the offset amount calculated in step S102).

[0073] As shown in reference numeral 632, the control unit 2 adjusts the RF power (HF Power) of the source RF signal (HF Power Offset).

[0074] Then, the control unit 2 returns to step S103, and the processing from step S103 to step S105 is repeated. As a result, the power supply control unit 230 sequentially corrects the RF power (HF Power) of the source RF signal by the offset amount calculated in step S105.

[0075] Here, as shown by reference numeral 640, the control unit 2 controls the plasma processing apparatus 1 to perform plasma processing on the next batch of production substrates. Also, as shown by reference numeral 632, the RF power (HF Power) of the source RF signal adjusted in step S105 is used. Also, as shown by reference numeral 641, when performing plasma processing on the production substrates, the measurement unit 210 measures the peak-to-peak voltage (HF Vpp) of the source RF signal. The measurement unit 210 measures the peak-to-peak voltage (HF Vpp) of the source RF signal based on the detection signal of the detection circuit 33a. The measured peak-to-peak voltage (HF Vpp) of the source RF signal is then stored in the storage unit 220. The process may be repeated in the same manner thereafter.

[0076] Thus, in the control of the plasma processing apparatus 1 according to one embodiment, the RF power (HF Power) of the source RF signal is controlled to maintain the stability of the peak-to-peak voltage (HF Vpp) of the source RF signal. Specifically, the peak-to-peak voltage (HF Vpp) of the source RF signal decreases as the parts in the plasma processing chamber 10 are consumed by the plasma. The control unit 2 performs plasma processing on one substrate with the plasma processing apparatus 1 and measures the electrical elements during plasma processing. Here, the peak-to-peak voltage (HF Vpp) of the source RF signal is measured as an electrical element. Then, after plasma processing on one substrate, when the plasma processing apparatus 1 performs plasma processing on another substrate, the control unit 2 controls the system to increase the high-frequency power of the high-frequency signal based on the measured electrical elements. Here, the RF power (HF Power) of the source RF signal is controlled to increase based on the peak-to-peak voltage (HF Vpp) of the source RF signal as a measured electrical element.

[0077] This makes it possible to suppress fluctuations in the plasma density of the plasma generated in the plasma processing space 10s. In addition, it is possible to stabilize the characteristics (e.g., processed shape, electrical characteristics, etc.) of the product (e.g., semiconductor device) formed on the substrate W by plasma processing.

[0078] In the flowchart shown in Figure 8, an example configuration is described in which the RF power (HF Power) of the source RF signal is adjusted based on the measured peak-to-peak voltage (HF Vpp) of the source RF signal each time a predetermined number of manufacturing substrates (e.g., one lot) are plasma-treated. However, the configuration is not limited to this example.

[0079] For example, the control unit 2 may be configured to determine whether the measured peak-to-peak voltage (HF Vpp) of the source RF signal is within a predetermined voltage range that includes a target value, and if it determines that it is not within the voltage range, it may adjust the RF power (HF Power) of the source RF signal based on the measured peak-to-peak voltage (HF Vpp) of the source RF signal.

[0080] For example, a predetermined voltage range including a target value has an upper threshold and a lower threshold. The control unit 2 may be configured to adjust the RF power of the source RF signal based on the measured peak-to-peak voltage (HF Vpp) of the source RF signal when it determines that the measured peak-to-peak voltage (HF Vpp) of the source RF signal is less than the lower threshold. Alternatively, the control unit 2 may be configured to adjust the RF power of the source RF signal based on the measured peak-to-peak voltage (HF Vpp) of the source RF signal when it determines that the measured peak-to-peak voltage (HF Vpp) of the source RF signal is greater than the upper threshold. Furthermore, the control unit 2 may be configured to maintain the RF power of the source RF signal when it determines that the measured peak-to-peak voltage (HF Vpp) of the source RF signal is within a predetermined voltage range including a target value (greater than or equal to the lower threshold and less than or equal to the upper threshold).

[0081] Alternatively, each time a predetermined number of manufacturing substrates (e.g., one lot) are plasma-treated, it may be possible to determine whether the average value of the measured peak-to-peak voltage (HF Vpp) of the source RF signal falls within a predetermined voltage range that includes a target value. If it is determined that the voltage is not within the range, the RF power (HF Power) of the source RF signal may be adjusted based on the measured peak-to-peak voltage (HF Vpp) of the source RF signal.

[0082] For example, a predetermined voltage range including a target value has an upper threshold and a lower threshold. The control unit 2 may be configured to adjust the RF power (HF Power) of the source RF signal based on the average value of the peak-to-peak voltage (HF Vpp) of the measured source RF signal each time a predetermined number of manufacturing substrates (e.g., one lot) are plasma-treated, if it determines that the average value of the peak-to-peak voltage (HF Vpp) of the measured source RF signal is less than the lower threshold. Alternatively, the control unit 2 may be configured to adjust the RF power (HF Power) of the source RF signal based on the average value of the peak-to-peak voltage (HF Vpp) of the measured source RF signal each time a predetermined number of manufacturing substrates (e.g., one lot) are plasma-treated, if it determines that the average value of the peak-to-peak voltage (HF Vpp) of the measured source RF signal is greater than the upper threshold. Furthermore, the control unit 2 may be configured to maintain the RF power (HF Power) of the source RF signal each time a predetermined number of manufacturing substrates (for example, one lot) are plasma-treated, if it determines that the average value of the peak-to-peak voltage (HF Vpp) of the measured source RF signal is within a predetermined voltage range including the target value (above a lower threshold and below an upper threshold; below a lower threshold of 802 and below an upper threshold of 801 in Figures 10A and 10B described later).

[0083] <Other Controls of Plasma Processing Apparatus 1 in One Embodiment> Figures 9A and 9B are examples of graphs showing the peak-to-peak voltage (HF Vpp) of the source RF signal. In the graphs shown in Figures 9A and 9B, the horizontal axis represents the RF application time (Parts RFH). The vertical axis shows the peak-to-peak voltage (HF Vpp) of the source RF signal as a solid line.

[0084] This document describes a control mechanism to suppress fluctuations in the peak-to-peak voltage (HF Vpp) of the source RF signal due to wear and tear of parts. Furthermore, wear on the upper surface of the edge ring of the ring assembly 112 reduces the height of the sheath above the edge ring. This can cause the ion incidence angle near the outer edge of the substrate W to change inward. To address this, a third voltage signal (bias signal, e.g., DC voltage) is supplied to the edge ring to adjust the thickness of the sheath above the edge ring, thereby adjusting the ion incidence angle near the edge of the substrate W. For example, by adjusting the third voltage signal supplied to the edge ring so that the height of the sheath above the substrate W is equal to the height of the sheath above the edge ring, the ion incidence angle near the outer edge of the substrate W is controlled to be perpendicular to the surface of the substrate W. This extends the lifespan of the edge ring.

[0085] In Figure 9A, the RF power (HF Power) of the source RF signal is controlled to increase with the elapsed RF application time (see Figure 5B). Here, supplying a third voltage signal to the edge ring affects the plasma density and thus affects the control of the peak-to-peak voltage (HF Vpp) of the source RF signal. As a result, fluctuations 701 may occur in the peak-to-peak voltage (HF Vpp) of the source RF signal.

[0086] Figure 9B demonstrates the simultaneous control of ion incidence angle (tilting control) and plasma density. This suppresses fluctuations in the peak-to-peak voltage (HF Vpp) of the source RF signal. In other words, it suppresses fluctuations in the plasma density of the plasma generated in the plasma processing space 10s.

[0087] Figures 10A and 10B are examples of graphs showing the change in the peak-to-peak voltage (HF Vpp) of the source RF signal. The horizontal axis represents the number of substrates W processed by the plasma processing apparatus 1. In other words, the horizontal axis corresponds to the operating time of the plasma processing apparatus 1 (e.g., RF application time). The vertical axis represents the peak-to-peak voltage (HF Vpp) of the source RF signal. FRDC is the voltage value of the third voltage signal supplied to the edge ring. In the example of Figures 10A and 10B, as the number of substrates W processed increases and a predetermined number of processing times are reached, the voltage value of the third voltage signal supplied to the edge ring is increased. This enables tilt control.

[0088] Here, the target value of 800 for the peak-to-peak voltage (HF Vpp) of the source RF signal is shown by a thin solid line. The upper limit threshold 801 for the dead zone of the peak-to-peak voltage (HF Vpp) of the source RF signal is shown by a dashed line. The lower limit threshold 802 for the dead zone of the peak-to-peak voltage (HF Vpp) of the source RF signal is also shown by a dashed line.

[0089] (Reference Example) In the example of Figure 10A, the actual value (measured value) 811 of the peak-to-peak voltage (HF Vpp) of the source RF signal measured by the measurement unit 210 is shown by a white circle and a thick solid line. The moving average value 812 of the peak-to-peak voltage (HF Vpp) of the source RF signal is shown by a black circle and a dashed line.

[0090] In the example shown in Figure 10A, the actual value 811 of the peak-to-peak voltage (HF Vpp) of the source RF signal is measured each time the substrate is processed (see step S103 in Figure 8). Also, the predetermined number of substrates processed in step S104 is set to one.

[0091] In step S105, the control unit 2 calculates a moving average value 812 from the actual peak-to-peak voltage (HF Vpp) values ​​811 of the source RF signal for the most recent three substrate processing cycles. Once the moving average value 812 is calculated, the control unit 2 determines the RF power (HF Power) of the source RF signal based on the calculated moving average value 812 and controls the system with the determined RF power (HF Power) of the source RF signal. In other words, the period during which the RF power (HF Power) of the source RF signal is changed (adjusted) is one substrate processing cycle.

[0092] In the example shown in Figure 10A, after changing the voltage value (FRDC) of the third voltage signal supplied to the edge ring to 500V, the actual value of the peak-to-peak voltage (HF Vpp) of the source RF signal, 811, oscillates significantly.

[0093] (Operation Example) In the example in Figure 10B, the actual value (measured value) 821 of the peak-to-peak voltage (HF Vpp) of the source RF signal measured by the measurement unit 210 is shown by a white circle and a thick solid line. The moving average value 822 of the peak-to-peak voltage (HF Vpp) of the source RF signal is shown by a black circle and a dashed line.

[0094] In the example shown in Figure 10B, the actual value 821 of the peak-to-peak voltage (HF Vpp) of the source RF signal is measured each time the substrate is processed (see step S103 in Figure 8). Also, the predetermined number of substrates processed in step S104 is set to 2.

[0095] In step S105, the control unit 2 calculates a moving average value 822 from the actual peak-to-peak voltage (HF Vpp) of the source RF signal for the two most recent substrate processing cycles 821. Once the moving average value 822 is calculated, the control unit 2 determines the RF power (HF Power) of the source RF signal based on the calculated moving average value 822 and controls the system with the determined RF power (HF Power) of the source RF signal. In other words, the period during which the RF power (HF Power) of the source RF signal is changed (adjusted) is two substrate processing cycles.

[0096] In the example in Figure 10B, after changing the voltage value (FRDC) of the third voltage signal supplied to the edge ring to 500V, the difference between the actual peak-to-peak voltage (HF Vpp) of the source RF signal (HF Vpp) of 811 and the target value of 800 becomes large, but the difference then decreases. In the example in Figure 10B, the fluctuation of the actual peak-to-peak voltage (HF Vpp) of the source RF signal (HF Vpp) of 821 can be suppressed compared to the example in Figure 10A.

[0097] In this way, by adjusting the number of data points used when calculating the moving average value 822 (three times in the example of Figure 10A, and two times in the example of Figure 10B) and the period during which the RF power (HF Power) of the source RF signal is changed (adjusted) (once in the example of Figure 10A, and twice in the example of Figure 10B), it is possible to achieve a control that is highly robust to large disturbances that affect plasma density, such as applying a voltage to the edge ring.

[0098] Therefore, even when a third voltage signal is supplied to the edge ring in response to wear of the edge ring, fluctuations in the RF power (HF Power) of the source RF signal can be suppressed. This makes it possible to suppress changes in plasma density.

[0099] Specifically, it is preferable to make the period during which the RF power (HF Power) of the source RF signal is changed (adjusted) (twice in the example of Figure 10B) equal to the number of data points used when calculating the moving average value 822 (twice in the example of Figure 10B). This makes it possible to suppress fluctuations in the actual value 821 of the peak-to-peak voltage (HF Vpp) of the source RF signal.

[0100] Furthermore, it is preferable that the period during which the RF power (HF Power) of the source RF signal is changed (adjusted) (the period for calculating the moving average value 822) be two or more times. For example, it is preferable that it be two times.

[0101] Furthermore, it is preferable that the number of data points used when calculating the moving average value 822 be at least two of the most recent substrate processing cycles. For example, two cycles is preferable.

[0102] (Sheath Adjuster) Next, an example of a sheath adjuster configured to adjust the vertical position of the upper end of the sheath above the edge ring will be further explained using Figures 11A and 11B. Figures 11A and 11B are examples of schematic cross-sectional diagrams showing the position of the substrate support portion 11 and the upper end of the sheath. In Figures 11A and 11B, the position of the upper end of the sheath is shown by a dashed line. The direction of incidence of ions incident on the substrate W is also indicated by an arrow.

[0103] The ring assembly 112 includes an edge ring 1121 and an insulating ring 1122.

[0104] Furthermore, the device includes a power supply 35 configured to apply a third voltage signal (bias signal) to the edge ring 1121 as a sheath adjuster.

[0105] As shown in Figure 11A, the upper surface of the edge ring 1121 is worn down by the plasma treatment of the substrate W. As the upper surface of the edge ring 1121 is worn down, its vertical position becomes lower. When the vertical position of the upper surface of the edge ring 1121 becomes lower, the upper end position of the sheath above the edge ring 1121 becomes lower than the upper end position of the sheath above the substrate W. As a result, the upper end of the sheath is tilted near the edge of the substrate W, and the direction of propagation of ions supplied to the edge of the substrate W becomes tilted with respect to the vertical direction.

[0106] The control unit 2 controls the power supply 35, which acts as a sheath adjuster, to apply a third voltage signal (bias signal) to the edge ring 1121. This adjusts the vertical position of the upper end of the sheath above the edge ring 1121, as shown in Figure 11B. As a result, the difference between the upper end position of the sheath above the edge ring 1121 and the upper end position of the sheath above the substrate W is eliminated or reduced. Consequently, the direction of ion propagation supplied to the edge of the substrate W can be brought closer to the vertical direction.

[0107] Next, another example of a sheath adjuster configured to adjust the vertical position of the upper end of the sheath above the edge ring will be further described with reference to Figures 12A and 12B. Figures 12A and 12B are another example of a schematic cross-sectional view showing the position of the substrate support 11 and the upper end of the sheath. In Figures 12A and 12B, the position of the upper end of the sheath is shown by a dashed line. The direction of incidence of ions incident on the substrate W is indicated by an arrow.

[0108] The ring assembly 112A includes an annular member 1121A, an edge ring 1121B, and an insulating ring 1122.

[0109] Furthermore, the sheath adjuster includes a lift pin 15 and a drive unit 16 configured to move the edge ring 1121B upward.

[0110] As shown in Figure 12A, the upper surface of the edge ring 1121B is worn down by the plasma treatment of the substrate W. As the upper surface of the edge ring 1121B is worn down, the vertical position of the upper surface of the edge ring 1121B becomes lower. When the vertical position of the upper surface of the edge ring 1121B becomes lower, the upper end position of the sheath above the edge ring 1121B becomes lower than the upper end position of the sheath above the substrate W. As a result, the upper end of the sheath is tilted near the edge of the substrate W, and the direction of propagation of ions supplied to the edge of the substrate W becomes tilted with respect to the vertical direction.

[0111] The control unit 2 controls the drive unit 16, which acts as a sheath adjuster, to raise the lift pin 15 and lift the edge ring 1121B upward. This adjusts the vertical position of the upper surface of the edge ring 1121B, and adjusts the vertical position of the upper end of the sheath above the edge ring 1121. As a result, the difference between the upper end position of the sheath above the edge ring 1121 and the upper end position of the sheath above the substrate W is eliminated or reduced. Consequently, the direction of ion propagation supplied to the edge of the substrate W can be brought closer to the vertical direction.

[0112] It should be noted that the present invention is not limited to the configurations shown in the above embodiments, including combinations with other elements. These aspects can be modified without departing from the spirit of the present invention and can be appropriately determined according to their application.

[0113] The embodiments disclosed above include, for example, the following aspects: (Note 1) A plasma processing apparatus comprising: a plasma processing chamber; a substrate support portion provided in the plasma processing chamber for supporting a substrate; a gas introduction portion for introducing at least one processing gas into the plasma processing chamber; a power supply for supplying a high-frequency signal to an electrode; an edge ring surrounding the substrate supported by the substrate support portion; a sheath adjuster configured to adjust the vertical position of the upper end of a sheath above the edge ring; and a control unit, wherein the control unit controls the sheath adjuster to adjust the vertical position of the upper end of the sheath; performs plasma processing on one substrate with the plasma processing apparatus, measures electrical elements during plasma processing; and, after plasma processing of the one substrate, controls the high-frequency power of the high-frequency signal based on the measured electrical elements when performing plasma processing on another substrate with the plasma processing apparatus. (Note 2) The plasma processing apparatus according to Note 1, wherein the sheath adjuster is configured to apply a voltage to the edge ring in order to adjust the vertical position of the upper end of the sheath. (Note 3) The plasma processing apparatus according to Note 1, wherein the sheath adjuster is configured to move the edge ring upward in order to adjust the position of the upper end of the sheath in the vertical direction. (Note 4) The plasma processing apparatus according to Note 1, wherein the control unit determines the high-frequency power of the high-frequency signal based on the measured moving average value of the electrical elements when the number of substrates that have been subjected to plasma processing has exceeded a predetermined number, and controls the determined high-frequency power of the high-frequency signal when the plasma processing apparatus is used to perform plasma processing on the other substrates. (Note 5) The plasma processing apparatus according to Note 4, wherein the predetermined number of substrates and the number of data used to calculate the moving average value are equal. (Note 6) The plasma processing apparatus according to any one of Notes 1 to 5, wherein the control unit controls the high-frequency power of the high-frequency signal to increase when the plasma processing apparatus is used to perform plasma processing on the other substrates.(Note 7) The plasma processing apparatus according to any one of Notes 1 to 6, wherein the electrical element is the peak-to-peak voltage of the high-frequency signal supplied to the electrode. (Note 8) The plasma processing apparatus according to any one of Notes 1 to 7, wherein the high-frequency signal supplied to the electrode includes a source high-frequency signal for plasma generation and a bias high-frequency signal having a lower frequency than the source high-frequency signal that generates a bias potential on the substrate, and the electrical element is the peak-to-peak voltage of the source high-frequency signal. (Note 9) The plasma processing apparatus according to Note 8, wherein the control unit controls the high-frequency power of the source high-frequency signal when the plasma processing apparatus performs plasma processing on the other substrate. (Note 10) The plasma processing apparatus according to any one of Notes 1 to 9, wherein the high-frequency power of the high-frequency signal is controlled based on the difference between the measured electrical element and the target value of the electrical element, and information showing the correspondence between the increase in the electrical element and the increase in the high-frequency power of the high-frequency signal. (Note 11) The plasma apparatus according to any one of Notes 1 to 10, wherein the control unit performs plasma processing on a plurality of substrates including the one substrate using the plasma apparatus, measures the electrical elements during the plasma processing, and after the plasma processing on the plurality of substrates including the one substrate, when performing plasma processing on the other substrates using the plasma apparatus, controls the high-frequency power of the high-frequency signal based on the electrical elements measured on the plurality of substrates including the one substrate. (Note 12) The plasma apparatus according to Note 11, wherein the control unit performs plasma processing on the other substrates using the plasma apparatus, controls the high-frequency power of the high-frequency signal based on the average value of the electrical elements measured on the plurality of substrates including the one substrate.(Note 13) The plasma processing apparatus according to any one of Notes 1 to 12, comprising: an impedance matching circuit provided between the power supply and the electrode, having an input terminal connected to the power supply and an output terminal connected to the electrode; and a detection circuit that detects at least one of the current, voltage, and power at the output terminal of the impedance matching circuit and outputs a detection signal, wherein the control unit measures the electrical elements based on the detection signal of the detection circuit. (Note 14) The plasma processing apparatus according to any one of Notes 1 to 13, wherein the gas introduction section includes a shower head disposed above the substrate support section, and the electrode has a lower electrode included in the substrate support section and an upper electrode included in the shower head. (Note 15) The plasma processing apparatus according to Note 14, wherein the high-frequency signal supplied to the electrode includes a source high-frequency signal for plasma generation and a bias high-frequency signal that generates a bias potential on the substrate and has a lower frequency than the source high-frequency signal, and the power supply supplies the source high-frequency signal to the upper electrode and the bias high-frequency signal to the lower electrode. (Note 16) A control method for a plasma processing apparatus that performs plasma processing on a substrate, comprising: a plasma processing chamber; a substrate support portion provided in the plasma processing chamber for supporting a substrate; a gas introduction portion for introducing at least one processing gas into the plasma processing chamber; a power supply for supplying a high-frequency signal to an electrode; an edge ring surrounding the substrate supported by the substrate support portion; and a sheath adjuster configured to adjust the vertical position of the upper end of the sheath above the edge ring, wherein the plasma processing apparatus controls the sheath adjuster to adjust the vertical position of the upper end of the sheath; performs plasma processing on one substrate with the plasma processing apparatus, measures the electrical elements during the plasma processing; and after the plasma processing on one substrate, when performing plasma processing on another substrate with the plasma processing apparatus, controls the high-frequency power of the high-frequency signal based on the measured electrical elements.(Note 17) The control method for a plasma processing apparatus according to Note 16, wherein the sheath adjuster is configured to apply a voltage to the edge ring in order to adjust the position of the upper end of the sheath in the vertical direction. (Note 18) The control method for a plasma processing apparatus according to Note 16, wherein the sheath adjuster is configured to move the edge ring upward in order to adjust the position of the upper end of the sheath in the vertical direction.

[0114] Furthermore, this application claims priority based on Japanese Patent Application No. 2025-016962, filed on February 4, 2025, and the entire contents of these Japanese Patent Applications are incorporated herein by reference.

[0115] W Substrate 1 Plasma processing apparatus 10 Plasma processing chamber 10s Plasma processing space 11 Substrate support section 112 Ring assembly (edge ​​ring) 12 Plasma generation section 13 Shower head (gas introduction section) 30 Power supply system 31 Power supply 31a First RF generation section 31b Second RF generation section 32 Power supply 33, 34 Impedance matching circuit 33a, 34a Detection circuit 35 Power supply (bias power supply) 35a Third voltage generation section 2 Control section 210 Measurement section 220 Storage section 230 Power supply control section

Claims

1. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support portion provided within the plasma processing chamber for supporting a substrate; a gas introduction portion for introducing at least one processing gas into the plasma processing chamber; a power supply for supplying a high-frequency signal to an electrode; an edge ring surrounding the substrate supported by the substrate support portion; a sheath adjuster configured to adjust the vertical position of the upper end of the sheath above the edge ring; and a control unit, wherein the control unit controls the sheath adjuster to adjust the vertical position of the upper end of the sheath; and the plasma processing apparatus performs plasma processing on one substrate, measures the electrical elements during plasma processing, and, after plasma processing on one substrate, controls the high-frequency power of the high-frequency signal based on the measured electrical elements when performing plasma processing on another substrate with the plasma processing apparatus.

2. The plasma processing apparatus according to claim 1, wherein the sheath adjuster is configured to apply a voltage to the edge ring in order to adjust the position of the upper end of the sheath in the vertical direction.

3. The plasma processing apparatus according to claim 1, wherein the sheath adjuster is configured to move the edge ring upward in order to adjust the position of the upper end of the sheath in the vertical direction.

4. The plasma processing apparatus according to claim 1, wherein the control unit determines the high-frequency power of the high-frequency signal based on the measured moving average value of the electrical elements when the number of substrates that have been subjected to plasma processing has exceeded a predetermined number, and controls the determined high-frequency power of the high-frequency signal when performing plasma processing on other substrates with the plasma processing apparatus.

5. The plasma processing apparatus according to claim 4, wherein the predetermined number of processing sheets is equal to the number of data points used to calculate the moving average value.

6. The plasma apparatus according to claim 1, wherein the control unit controls the plasma apparatus to increase the high-frequency power of the high-frequency signal when performing plasma processing on the other substrate with the plasma apparatus.

7. The plasma processing apparatus according to claim 6, wherein the electrical element is the peak-to-peak voltage of the high-frequency signal supplied to the electrode.

8. The plasma apparatus according to claim 7, wherein the high-frequency signal supplied to the electrode includes a source high-frequency signal for plasma generation and a bias high-frequency signal having a lower frequency than the source high-frequency signal for generating a bias potential on the substrate, and the electrical element is the peak-to-peak voltage of the source high-frequency signal.

9. The plasma apparatus according to claim 8, wherein the control unit controls the high-frequency power of the source high-frequency signal when the plasma apparatus performs plasma processing on the other substrate.

10. A plasma processing apparatus according to any one of claims 1 to 9, wherein the high-frequency power of the high-frequency signal is controlled based on the difference between the measured electrical element and the target value of the electrical element, and information showing the correspondence between the amount of increase in the electrical element and the amount of increase in the high-frequency power of the high-frequency signal.

11. The plasma apparatus according to any one of claims 1 to 9, wherein the control unit performs plasma processing on a plurality of substrates including the one substrate using the plasma apparatus, measures the electrical elements during the plasma processing, and after the plasma processing on the plurality of substrates including the one substrate, when performing plasma processing on the other substrates using the plasma apparatus, controls the high-frequency power of the high-frequency signal based on the electrical elements measured on the plurality of substrates including the one substrate.

12. The plasma apparatus according to claim 11, wherein the control unit controls the high-frequency power of the high-frequency signal based on the average value of the electrical elements measured on a plurality of substrates, including the one substrate, when the plasma apparatus performs plasma treatment on the other substrates.

13. The plasma processing apparatus according to any one of claims 1 to 9, comprising: an impedance matching circuit provided between the power supply and the electrode, having an input terminal connected to the power supply and an output terminal connected to the electrode; and a detection circuit that detects at least one of the current, voltage, and power at the output terminal of the impedance matching circuit and outputs a detection signal, wherein the control unit measures the electrical elements based on the detection signal of the detection circuit.

14. The plasma processing apparatus according to any one of claims 1 to 9, wherein the gas introduction section includes a shower head positioned above the substrate support section, and the electrode comprises a lower electrode included in the substrate support section and an upper electrode included in the shower head.

15. The plasma processing apparatus according to claim 14, wherein the high-frequency signal supplied to the electrode includes a source high-frequency signal for plasma generation and a bias high-frequency signal having a lower frequency than the source high-frequency signal that generates a bias potential on the substrate, and the power supply supplies the source high-frequency signal to the upper electrode and the bias high-frequency signal to the lower electrode.

16. A control method for a plasma processing apparatus comprising: a plasma processing chamber; a substrate support portion provided within the plasma processing chamber for supporting a substrate; a gas introduction portion for introducing at least one processing gas into the plasma processing chamber; a power supply for supplying a high-frequency signal to an electrode; an edge ring surrounding the substrate supported by the substrate support portion; and a sheath adjuster configured to adjust the vertical position of the upper end of a sheath above the edge ring, wherein the plasma processing apparatus performs plasma processing on a substrate, the control method for the sheath adjuster to adjust the vertical position of the upper end of the sheath; plasma processing of one substrate with the plasma processing apparatus, measuring the electrical elements during plasma processing; and, after plasma processing of the one substrate, controlling the high-frequency power of a high-frequency signal based on the measured electrical elements when plasma processing another substrate with the plasma processing apparatus.

17. The control method for a plasma processing apparatus according to claim 16, wherein the sheath adjuster is configured to apply a voltage to the edge ring in order to adjust the position of the upper end of the sheath in the vertical direction.

18. The control method for a plasma processing apparatus according to claim 16, wherein the sheath adjuster is configured to move the edge ring upward in order to adjust the position of the upper end of the sheath in the vertical direction.

Images